Technical field
[0001]
The present invention relates to a threaded joint.
BACKGROUND
[0002]
Oil wells, natural gas wells (hereinafter collectively referred to as "oil wells") in the casing, as OCTG such as tubing, sequentially linked steel tube is used with a screw joint.
[0003]
　In recent years, such as in particular shale wells have been underway mined by the horizontal digging emphasizes the efficiency of production. Such threaded joint for oil well pipes used in applications, it is required with high torque. To increase the torque performance of the threaded joint, for example, in US Patent 6,206,436 discloses or Kohyo 2013-507596, a thread shape is a wedge-shaped, gradually changing the screw width across threaded portion (e.g., at pin tip gradually decreases the width of the thread towards, the box, and vice versa) technology, which structure is disclosed. Further, as a similar technique to this, WO2015 / 083382A1, also discloses a technique for the thread shape and trapezoidal.
Summary of the Invention
[0004]
　In general, the threaded joint, at a predetermined torque range, various properties (hereinafter, take sealability example) determined is designed to be exhibited. In other words, even over torque beyond the proper range, the rather impair the sealing property.
[0005]
　Therefore, for example, in a threaded joint which high torque having a structure as in Patent Document 1 is required, it is designed to exert a proper sealing property when entered into high torque. In such a threaded joint, it is not expressed proper sealability be fastened at a low torque in reverse. Further, a trapezoidal screw thread such as in Patent Document 3, when fastened by the high torque, a force is applied in the direction in which the external thread and the internal thread away from each other, easily disengaged.
[0006]
　According to this embodiment, a range of torque predetermined performance can be obtained to provide a wide threaded joint.
[0007]
　According to this embodiment, a threaded joint is a threaded joint for connecting a tube comprises a pin having a wedge-shaped external thread comprising thread width variable portion, and a box with a wedge-shaped internal thread comprising thread width variable portion. External thread meshes with the female thread. The threaded joint, when the insertion plane and load flanks of the external thread is in contact with the insert surface and the load flanks of the internal thread, respectively, the shoulder provided on the pin is not in contact with the shoulder provided on the other member, further when rotated in the fastening direction, before the threaded portion breaks down, has a structure in which a shoulder provided on the pin can contact the shoulder provided on the other member.
[0008]
　In a threaded joint according to this embodiment can broaden the torque range in which a predetermined performance is obtained. Therefore, it can be widely applicable range of the threaded joint.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009]
[1] Figure 1 is a longitudinal sectional view of a threaded joint according to the first embodiment.
FIG. 2 is an enlarged longitudinal sectional view of the male screw and the female screw shown in FIG.
[Figure 2A] Figure 2A is an enlarged longitudinal sectional view of the screw constant width portion shown in FIG.
[Figure 2B] Figure 2B is an enlarged longitudinal sectional view of the screw-width variable region shown in Figure 2.
[Figure 2C] FIG 2C is an enlarged longitudinal sectional view when locked flank near shoulder shown in FIG.
FIG 2D] FIG 2D is an enlarged longitudinal sectional view of when rotated further in the fastening direction than when locked flank shoulder peripheral shown in FIG.
FIG. 3 is a graph showing the stab lead and load leads of the pin and box.
[4] FIG. 4 is a diagram showing a torque chart during fastening of the threaded joint shown in Figure 1.
FIG. 5 is a longitudinal sectional view of the vicinity of the leading end portion of the pin of a threaded joint is a diagram showing the deformation behavior of the pin with the progress of fastening.
[Figure 6A] Figure 6A is a diagram showing the relationship between the torque and the number of turns in without shoulder contact.
[Figure 6B] Figure 6B is a diagram showing the relationship between the torque and the number of turns in there shoulder contact.
[Figure 6C] Figure 6C is a graph showing the external thread of the processing time with and without threaded constant width portion.
[7] FIG. 7 is a longitudinal sectional view of a threaded joint according to a first modification of the first embodiment.
[8] FIG. 8 is a longitudinal sectional view of a threaded joint according to a second modification of the first embodiment.
[9] FIG. 9 is a longitudinal sectional view of a threaded joint according to a third modification of the first embodiment.
FIG 9A] FIG 9A is a longitudinal sectional view of an enlarged tip of the pin in the threaded joint according to a fourth modification of the first embodiment.
[10] FIG 10 is a longitudinal sectional view of a threaded joint according to the second embodiment.
[11] FIG 11 is a longitudinal sectional view of a threaded joint according to a first modification of the second embodiment.
[12] FIG 12 is a longitudinal sectional view of a threaded joint according to a second modification of the second embodiment.
[13] FIG 13 is a longitudinal sectional view of a threaded joint according to a third modification of the second embodiment.
[14] FIG 14 is a longitudinal sectional view of a threaded joint according to the third embodiment.
[Figure 15A] Figure 15A, in a threaded joint shown in FIG. 14 is a longitudinal sectional view of the intermediate shoulder are not in contact when the thread interference torque is obtained.
[FIG. 15B] FIG 15B, in a threaded joint shown in FIG. 14 is a longitudinal sectional view of the intermediate shoulder is in contact when the thread interference torque is obtained.
[16] FIG 16 is a longitudinal sectional view of a threaded joint according to a first modification of the third embodiment.
[17] FIG 17 is a longitudinal sectional view of a threaded joint according to a second modification of the third embodiment.
[18] FIG 18 is a longitudinal sectional view of a threaded joint according to a third modification of the third embodiment.
[19] FIG 19 is a longitudinal sectional view of a threaded joint according to the fourth embodiment.
[FIG. 20A] FIG 20A, in the threaded joint shown in FIG. 19 is a longitudinal sectional view of the shoulder is not in contact when the thread interference torque is obtained.
[FIG. 20B] FIG 20B, in a threaded joint shown in FIG. 19 is a longitudinal sectional view of the shoulder is in contact when the thread interference torque is obtained.
[21] FIG 21 is a longitudinal sectional view of a threaded joint according to a first modification of the fourth embodiment.
[22] FIG 22 is a longitudinal sectional view of a threaded joint according to a second modification of the fourth embodiment.
FIG. 23 is a longitudinal sectional view of a threaded joint according to a third modification of the fourth embodiment.
FIG. 24 is a longitudinal sectional view of a threaded joint according to the fifth embodiment.
[FIG. 25A] FIG 25A, in the threaded joint shown in FIG. 24 is a longitudinal sectional view of the shoulder is not in contact when the thread interference torque is obtained.
[FIG. 25B] FIG 25B, in a threaded joint shown in FIG. 24 is a longitudinal sectional view of the shoulder is in contact when the thread interference torque is obtained.
FIG. 26 is a longitudinal sectional view of a threaded joint according to a first modification of the fifth embodiment.
[27] FIG 27 is a longitudinal sectional view of a threaded joint according to a second modification of the fifth embodiment.
FIG. 28 is a longitudinal sectional view of a threaded joint according to a third modification of the fifth embodiment.
[29] FIG 29 is a longitudinal sectional view of a threaded joint according to the sixth embodiment.
FIG 30A] FIG 30A, in the threaded joint shown in FIG. 29 is a longitudinal sectional view of the shoulder is not in contact when the thread interference torque is obtained.
[Fig. 30B] FIG 30B, in a threaded joint shown in FIG. 29 is a longitudinal sectional view of the shoulder is in contact when the thread interference torque is obtained.
FIG. 31 is a longitudinal sectional view of a threaded joint according to a first modification of the sixth embodiment.
FIG. 32 is a longitudinal sectional view of a threaded joint according to a second modification of the sixth embodiment.
FIG. 33 is a longitudinal sectional view of a threaded joint according to a third modification of the sixth embodiment.
[34] FIG 34 is a longitudinal sectional view of a trapezoidal thread.
[Figure 35A] Figure 35A is a longitudinal sectional view of the screw width variable portion in the case of using the threaded joint showing the trapezoidal screw in Figure 1.
[Figure 35B] Figure 35B is a longitudinal sectional view of the screw constant width portion when used in a threaded joint showing the trapezoidal screw in Figure 1.
DESCRIPTION OF THE INVENTION
[0010]
　[Configuration 1]
　According to this embodiment, threaded joint, a threaded joint for connecting a pipe, and a box having a pin having a wedge-shaped external thread comprising thread width varying portions, the wedge-shaped internal thread comprising thread width variable portion equipped with a. External thread meshes with the female thread. The threaded joint, when the insertion plane and load flanks of the external thread is in contact with the insert surface and the load flanks of the internal thread, respectively, the shoulder provided on the pin is not in contact with the shoulder provided on the other member, further when rotated in the fastening direction, before the threaded portion breaks down, has a structure in which a shoulder provided on the pin can contact the shoulder provided on the other member.
[0011]
　According to Configuration 1, when both the insert surface and the load flanks of the external thread is in contact with the insert surface and the load flanks of the internal thread, respectively, the shoulder provided on the pin is not in contact with the shoulder provided on the other member also, by inserting surfaces and load flanks of the male thread from interfering with the insertion face and load flanks of the internal thread, respectively, the torque rises from the torque at the time locked flank to shouldering torque, when rotated further in the fastening direction, before threaded portion breaks down, the shoulder provided on the pin contacts the shoulder provided on the other member, the torque is further increased to more than shouldering torque. The insertion surface and load flanks of the male threads by contact with insert surfaces and load flanks of the internal thread, respectively, the sealing performance in the screw portion is ensured. Further, since the external thread and the internal thread are wedge-shaped, hardly disengaged external thread of the pin from the box of the female screw, the torque is liable to rise.
[0012]
　Accordingly, in a threaded joint according to this embodiment can broaden the range of torque given performance.
[0013]
　[Configuration 2]
　In the configuration 1, the thread width variable portion, the insertion surface of the external thread, the summit surfaces and loading surface, insertion surface of the internal thread, respectively, the valley in contact with the bottom surface and the load surface, thereby, the sealing properties of the threaded joint and it has a expression to the structure.
[0014]
　According to Configuration 2, it can ensure sealing performance in the threaded portion.
[0015]
　[Configuration 3]
　In the configuration 1 or 2, the threaded joint is to conclude with a coupling a pair of tubes. Pin is provided at the tube end of each tube of the pair of tubes, with a shoulder on the tip. Box is provided at both ends of the coupling. The threaded joint, when the insertion surface and the load flanks of the pin of the male screw of the pair of tubes is in contact with the insert surface and the load flanks of each box of the female screw, not in contact with the shoulder between the pin of the pair of tubes, when rotated further in the fastening direction, before the threaded portion breaks down, has a structure in which the shoulder between the pin of the pair of tubes may contact.
[0016]
　According to the configuration 3, when the insertion surface and the load flanks of the male thread of the pin provided on the pipe ends of a pair of tubes is in contact with the insert surface and the load flanks of each box of the female screw, insertion surface and load flanks of the male thread by interfering with the insertion face and load flanks of the internal thread, respectively, the torque rises from torque during locked flank to shouldering torque. Then, when rotated further in the fastening direction, before the threaded portion breaks down, the shoulder between the pin of the pair of tubes are in contact, torque is further increased to more than shouldering torque.
[0017]
　Therefore, the threaded joint of coupling type, can widen the range of torque given performance.
[0018]
　Configuration 4]
　In the structure 3, a pin on one of the pins of the pair of tubes further comprises an inner periphery which is formed in pin female sealing surface of the distal end portion. The other pin further comprises a pin male seal surface formed on the outer periphery of the distal end portion. Pin female sealing surface, the contact pins male sealing surface and the seal.
[0019]
　According to Configuration 4, a seal on pin male sealing surface and the pin female sealing surface mating contact between, high sealing performance than threaded joint sealing surface is not provided, to obtain a high sealing performance for particular pressure can.
[0020]
　Configuration 5]
　In the configuration 1 or 2, shoulder is provided at the tip of the pin. Shoulder corresponding to shoulder of the pin is provided on the box. The threaded joint, when the insertion plane and load flanks of the external thread is in contact with the insert surface and the load flanks of the internal thread, respectively, when the shoulder of the pin is not in contact with the shoulder of the box, which is further rotated in the fastening direction, before threaded portion breaks down, it has a structure in which the shoulder of the pin can contact the shoulder of the box.
[0021]
　According to Configuration 5, when the insertion surface and the load flanks of the pin external thread is in contact with the insert surface and the load flanks of the internal thread, respectively, by inserting surfaces and load flanks of the male thread from interfering with the insertion face and load flanks of the female thread, respectively , torque rises from the torque at the time of locked Frank to shouldering torque. Then, when rotated further in the fastening direction, before the threaded portion breaks down, when the shoulder of the pin contacts the shoulder of the box, the torque is further increased to more than shouldering torque.
[0022]
　Therefore, the threaded joint integral scheme, can widen the range of torque given performance.
[0023]
　Configuration 6]
　In the configuration 1 or 2, pin includes a plurality of stages of the external thread, and an intermediate shoulder provided between said plurality of stages of the external thread. Box has a plurality of stages of the internal thread, and an intermediate shoulder which is provided in correspondence with the intermediate shoulder of the pin between the plurality of stages of the internal thread. The threaded joint, when one of the stabbing flanks and the load flanks of the pin of the male thread provided on the tube ends of the tube of the pair of tubes is in contact with the insert surface and the load flanks of the internal thread, respectively, of the pin and the box intermediate shoulder each other not in contact, when rotated further in the fastening direction, before the threaded portion breaks down, having a structure intermediate the shoulder between the pin and the box may contact.
[0024]
　According to Configuration 6, when the insertion surface and a load surface of the pin of the male thread provided on the tube end of one pipe is in contact with the insert surface and the load flanks of the internal thread, respectively, the insertion plane and load flanks of the male thread, respectively the internal thread by interfering with the insertion face and load flanks, the torque rises from the torque at the time locked flank to shouldering torque, when further rotated in the fastening direction, before the threaded portion breaks down, the pin and box When the intermediate shoulder come into contact with each other, torque is further increased to more than shouldering torque.
[0025]
　Therefore, the threaded joint having a plurality of stages of screws, can be wider range of torque given performance.
[0026]
　Configuration 7]
　In the configuration 1 or 2, the distal end portion of the box shoulder is provided on the pin shoulder is provided corresponding to the shoulder of the box. The threaded joint, when the insertion plane and load flanks of the external thread is in contact with the insert surface and the load flanks of the internal thread, respectively, the shoulder between the box and pin are not in contact, when rotated further in the tightening direction, the screw before part breaks down, having a structure in which the shoulder between the box and pin may contact.
[0027]
　According to Configuration 7, when the insertion plane and load flanks of the external thread is in contact with the insert surface and the load flanks of the internal thread, respectively, by inserting surfaces and load flanks of the male thread from interfering with the insertion face and load flanks of the internal thread, respectively, the torque rises from the torque at the time locked flank to shouldering torque, when rotated further in the fastening direction, before the threaded portion breaks down, the shoulder between the box and the pin contact, by shoulder with each other to interfere , torque is further increased to more than shouldering torque.
[0028]
　Therefore, the threaded joint shoulder of the pin can contact the shoulder provided at the distal end of the box, can be wider range of torque given performance.
[0029]
　Configuration 8]
　In any of the configurations from the configuration 1 7, pin, in the tube axis direction, has a pin-side sealing surface located on the tube end side and / or the pipe main body side of the external thread, box pin side having box side sealing surface provided in correspondence with the sealing surface. Then, the pin-side sealing surface, the box side sealing surface and the sealing contact.
[0030]
　According to Configuration 8, the pin-side sealing surface and the box side sealing surface, with the screwing of the pin in contact with each other, in close contact with the fitting and on subsequent reaches the locked Frank, metal - form a seal by metal contact to.
[0031]
　Thus, in the threaded joint, the seals according to the pin-side sealing surface and the box side sealing surface mating contact between, it is possible to obtain a high sealing performance than threaded joint sealing surface is not provided.
[0032]
　Configuration 9]
　In any of the configurations from the configuration 1 8, the external thread and the internal thread further comprises a threaded constant width portion.
[0033]
　According to the structure 9, it can reduce the cycle time of the manufacture of the screw portion.
[0034]
　Moreover, the range of insertion surface and load flanks of the external thread is in contact with the insert surface and the load flanks of the internal thread, respectively, narrower than the threaded joint having only conventional thread width varying portions, the screw sealing performance due to an increase in screw lock surface pressure there is a possibility that can be improved.
[0035]
　It will be described in detail with reference to the drawings this embodiment. Incidentally, the description thereof will not be repeated like reference numerals denote the same or corresponding portions in the drawings.
[0036]
　[Embodiment 1]
　FIG. 1 is a longitudinal sectional view of a threaded joint according to the first embodiment. Incidentally, FIG. 1, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, the longitudinal sectional view shown in FIG. 1 to tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0037]
　Referring to FIG. 1, a threaded joint 10 according to the first embodiment includes a pin 1 and a box 3,4.
[0038]
　Threaded joint 10 is a threaded joint of the coupling type.
[0039]
　Pins 1 and 2 are provided in each of the tube ends of a pair of tubes 6, 7 to be connected.
[0040]
　Box 3 and 4, respectively, are provided on both sides of the tube axis CL direction of the coupling 5 for connecting a pair of tube 6,7.
[0041]
　Pin 1 includes, in order from the front end portion of the tube 6 has a shoulder 12 and external thread 11. Shoulder 12 is disposed at the distal end portion of the pin 1. External thread 11 is provided in a tapered shape between the shoulder 12 and the base 13 of the pin 1. Taper is, for example, 1/16. The external thread 11 has a chamfer surface 11c.
[0042]
　Pins 2, in order from the front end portion of the tube 7, having a shoulder 22 and externally threaded 21. Shoulder 22 is disposed at the distal end portion of the pin 2. Male thread 21 is provided in a tapered shape between the shoulder 22 and the base 23 of the pin 2. Taper is, for example, 1/16. The external thread 21 has a chamfer surface 21c.
[0043]
　Box 3 has an internal thread 31. Box 4 has an internal thread 41. Female thread 31 is provided in a tapered shape from the tip of the box 3 inward. Internal thread 41 is provided in a tapered shape from the tip of the box 4 toward the inside.
[0044]
　Internal thread 31 has a chamfer surface 31c corresponding to the chamfer surface 11c of the external thread 11. Internal thread 41 has a chamfer surface 41c corresponding to the chamfer surface 21c of the external thread 21.
[0045]
　Internal thread 41 of the internal thread 31, and the pin 2 male thread 21 and the box 4 of the external thread 11 and the box 3 of the pin 1 is fastened by screwed together.
[0046]
　During later be locked flanks, the tip of the pin 1 (shoulder 12) is not in contact with the tip of the pin 2 (shoulder 22). The addition of further rotated in the fastening direction from the state, the distal end portion of the pin 1 (shoulder 12) contacts the distal end of the pin 2 (shoulder 22) before the screw part (external thread 11 and internal thread 31) yields ( shown at right in FIG. 2 to be described later).
[0047]
　Shape of the tip portion of the pin 1 (shoulder 12) and pin 2 of the end portion (shoulder 22) is preferably perpendicular to the tube axis CL direction.
[0048]
　In this specification, the torque when the front end portion of the pin 1 (shoulder 12) is in contact with the tip of the pin 2 (shoulder 22), the distal end portion (shoulder 12) begins to interfere with the front end portion (shoulder 22) say shouldering torque.
[0049]
　Figure 2 is an enlarged longitudinal sectional view of the external thread 11 and internal thread 31 shown in FIG. Referring to FIG. 2, the external thread 11 and internal thread 31 has a threaded width variable portion 11A, and a screw constant width portion 11B. Screw width variable portion 11A is disposed on the shoulder 12 side of the pin 1. Screw constant width portion 11B is disposed on the base 13 side of the pin 1. The length in the tube axis CL direction of the screw-width variable portion 11A is equal to the length in the tube axis CL direction of the screw the constant width portion 11B. The length in the tube axis CL direction of the screw-width variable portion 11A may be different from the length in the tube axis CL direction of the screw the constant width portion 11B.
[0050]
　Screw constant width portion 11B, for example, counted from the front end portion of the pin 1 is started from the position of 5 crest eyes.
[0051]
　In the external thread 11, threaded constant width portion 11B is a region with a constant thread root width. Screw width variable portion 11A is a region having a progressively larger thread root width toward be more than thread root width of the thread constant width portion 11B from the threaded constant width section 11B on the tip of the pin 1. On the other hand, in the internal thread 31, threaded constant width portion 11B is a region with a constant thread width. Screw width variable portion 11A is gradually larger thread width toward a the thread width or more screws constant width portion 11B (the portion corresponding to the pin 1 tip) middle box 4 from the screw constant width section 11B it is a region with a. That is, in the screw-width variable portion 11A, stab lead dS insertion surface 111 is different from the load lead dL of load surface 112. In contrast, in the screw constant width portion 11B, stab lead dS insertion face 111 is the same as the load lead dL of load surface 112. For more information on the stub lead dS and load lead dL, it will be described later.
[0052]
　In thread width variable portion 11A, the insertion face 111 and the load surface 112 of the external thread 11, respectively, faces the insertion face 311 and the load surface 312 of the internal thread 31, thread crest surface 113 of the external thread 11, the internal thread 31 It faces the thread root bottom surface 313.
[0053]
　Then, when locked flank, insertion face 111 and the load surface 112 of the external thread 11, respectively, in contact with the insert surface 311 and load flanks 312 of the internal thread 31, thread crest surface 113 of the external thread 11, the internal thread 31 in contact with the thread root bottom surface 313. Thus, when locked flank, the external thread 11 of the screw-width variable portion 11A has no gap between the internal thread 31, in contact with the internal thread 31. With such a structure, it is possible to ensure the sealing performance in the threaded portion.
[0054]
　Also in threaded constant width portion 11B, insertion surface 111 and load flanks 112 of the external thread 11, respectively, face the insertion face 311 and the load surface 312 of the internal thread 31, thread crest surface 113 of the male thread, thread root bottom surface of the internal thread 31 It is 313 and the counter.
[0055]
　Then, when locked flank, insertion face 111 of the male thread 11, a gap 20 between the stabbing flanks 311 of the female screw 31, the load surface 112 of the external thread 11 contacts the load surface 312 of the internal thread 31, screw crest surface 113 of the external thread 11 is in contact with the thread root bottom surface 311 of the internal thread 31. Thus, when locked flank, the external thread 11 of the screw constant width portion 11B has a gap 20 between the internal thread 31 in the insertion surface 111 side.
[0056]
　In this structure, the threaded joint 10, (also referred to as "thread lock range".) Range insert surface 111 and load flanks 112 contacts the respective insertion surface 311 and load flanks 312, conventional threaded width variable portion less than a threaded joint having only. Therefore, compared to a threaded joint having only thread width varying portions, a large surface pressure applied to the screw locking range. Thus, there is a possibility that the sealing performance at the screw portion is improved.
[0057]
　Further, the screw joint 10, because it has a threaded width variable portion 11A and threaded constant width portion 11B, than a threaded joint having only thread width variable portion can be reduced cycle time during manufacturing. Also, because it has a threaded width variable portion 11B and threaded constant width portion 11B, than a threaded joint having only thread width variable portion, the difference between the minimum of the thread width and the maximum thread width of the external thread portion and the female threaded portion It becomes smaller. Therefore, the external thread portion and the internal thread portion, shear fracture at the root of the thread is less likely to occur with a minimum thread width.
[0058]
　In thread width variable portion 11A and threaded constant width portion 11B, flank angle and flank angle of the load flanks 112 of the insert surface 111 is a negative angle, i.e., a wedge screw. The flank angle is an angle formed between the vertical perpendicular plane to the tube axis CL direction flank of the insert surface 111 (or flank of the load face 112). Flank angle of the insert surface 111 is a counterclockwise direction is positive, the flank angle of the load surface 112 is clockwise positive. The negative angle is set to, for example, -1 ° ~ -10 °. Incidentally, the flank angle of the insertion face 111 may be the same as the flank angle of the load flanks 112, may be different.
[0059]
　In thread width variable portion 11A and threaded constant width portion 11B, the screw trough bottom 313 of the thread crest surface 113 and the internally threaded 31 of the external thread 11 has a shape composed of a surface corresponding to a cylindrical surface centered axis tube axis CL. Alternatively, thread root bottom surface 313 of the thread crest surface 113 and the internally threaded 31 of the external thread 11 may have a shape composed of a surface corresponding to the peripheral surface of the truncated cone having a central axis tube axis CL.
[0060]
　External thread 11 is preferably provided with a chamfer surface 11c. Chamfer surface 11c is an inclined surface connecting the valley bottom of the insertion face 111 and the external thread 11. Female thread 31 is preferably provided with a chamfer surface 31c corresponding to the chamfer surface 11c of the external thread 11.
[0061]
　In thread width variable portion 11A, at the time locked flank, chamfer surfaces 11c of the external thread 11 contacts the chamfer surface 31c of the internal thread 31. In contrast, in the screw constant width portion 11B, at the time locked flank, chamfer surfaces 11c of the external thread 11 does not contact the chamfer surface 31c of the internal thread 31.
[0062]
　By providing the chamfer surface, the insertion of the pin is facilitated, sealability in the screw portion is improved. Angle of chamfer surfaces 11c is suitably the range of 30 ° ~ 60 ° with respect to the valley bottom of the external thread 11.
[0063]
　Incidentally, the internal thread 41 of the external thread 21 and the box 4 of the pin 2 are made of the same structure as the internal thread 31 of the external thread 11 and the box 3 of the pin 1.
[0064]
　Figure 3 is a graph showing the stab lead and load leads of the pin and box. In the graph shown in FIG. 3, the vertical axis represents the read size and the horizontal axis is the thread number counted from the center of the pin tip or box.
[0065]
　Here, stab lead pins, as shown in FIGS. 2A and B, the distance in the tube axis CL direction between the insertion face 111 adjacent the external thread 11. Pin load lead, as shown in FIGS. 2A and B, the distance in the tube axis CL direction between the load surface 112 adjacent the external thread 11. Box stab lead is the distance in the tube axis CL direction between the insertion surface 311 adjoining the internal thread 31. Box load lead is the distance in the tube axis CL direction between the load surface 312 adjacent the internal thread 31.
[0066]
　As shown in FIG. 3, the tip portion of the pin 1, i.e. a screw width variable portion 11A of the male thread 11 (FIG. 2B), the larger the load lead than stab lead. Similarly, the central portion of the box, i.e. thread width variable portion of the internal thread 31 in (part corresponding to the screw-width variable portion 11A of the male thread 11), it is larger in the load lead than stab lead.
[0067]
　In the proximal portion of the pin 1, i.e. a screw constant width portion 11B of the male thread 11 (FIG. 2A), it is equal to the stab lead and load leads. Similarly, the ends of the box 3, i.e. threaded constant width portion of the internal thread 31 in the (screw width portion corresponding to the constant portion 11B of the external thread 11), it is equal to the stab lead and load leads.
[0068]
　Each load lead pin and box is constant over the entire threaded portion. However, in both of the pin and box, the stab lead changes. That is, in both the pin and box, stab lead is increased when switching from the threaded width variations at threaded constant width portion.
[0069]
　As can be seen from FIG. 3, the position of the screw-width variable portion is switched to the screw constant width portion at pin thread width variable section does not exactly match the position for switching the screw constant width portion at box. If completely matched the position between the pin and the box, it is because it is difficult to screw the pin into the box.
[0070]
　Figure 4 is a diagram showing a torque chart during fastening of the threaded joint 10 shown in FIG. 4, the vertical axis represents torque, and the horizontal axis represents the turn (rpm).
[0071]
　In FIG. 4, the external thread 21 of the pin 2 is screwed into the female screw 41 of the box 4, the assumption that the tip of the pin 2 (shoulder 22) is located in central coupling 5 in the tube axis CL direction , a description will be given of torque chart at the time of the conclusion of the screw joint 10.
[0072]
　Referring to FIG. 4, the clamping of the tube (makeup) proceeds, first, the internal thread 31 of the external thread 11 and the box 3 of the pin 1 are in contact with each other, the torque is gradually increased along a straight line k1. Then, the threaded width variable portion 11A of the pin 1, when the insertion face 111 and the load surface 112 of the external thread 11 is in contact with the insert surface 311 and load flanks 312 of the internal thread 31 of each box 3, torque, when locked flanks to reach the torque T_Lf.
[0073]
　In this specification, it locked and Frank time refers to when the insertion face 111 and the load surface 112 of the external thread 11 of the pin 1 is respectively in contact with the insert surface 311 and load flanks 312 of the internal thread 31 of the box 3.
[0074]
　When tightening of the tube (makeup) further proceeds from the time-locked flanks, external thread 11 interferes with the female screw 31, the torque is rapidly increased along a straight line k2.
[0075]
　Here, in the threaded joint structure tip of the pin does not contact the distal end portion of the other pins, torque, torque T_y when the threaded portion is breakdown (hereinafter, also referred to as "yield torque".) Is reached when , the threaded portion begins to surrender.
[0076]
　However, the screw joint 10, before the torque reaches the yield torque T_y, tip of the pin 1 (shoulder 12) in contact with the tip of the pin 2 (shoulder 22), the distal end tip portion (shoulder 12) part (shoulder 22) and starts to interfere (i.e., torque reaches the shouldering torque T_sh). After that, when advancing the clamping tube (makeup), torque is further rapidly increased along the curve k3.
[0077]
　In a threaded joint 10, the torque is in the region REG1 from the torque T_Lf when locked flank to shouldering torque T_sh, in threaded width variable portion 11A, by the external thread 11 of the pin 1 interferes with the internal thread 31 of the box 3 elevated, the shouldering torque T_sh more regions REG2, the pin 1 of the tip before the threaded portion (male thread 11 and internal thread 31) yields (shoulder 12) from interfering with the tip of the pin 2 (shoulder 22) It increased by.
[0078]
　Therefore, a threaded joint 10, the screw portion the pin 1 of the tip before the (external thread 11 and internal thread 31) breaks down into contact with (shoulder 12) tip of the pin 2 in (shoulder 22), the pin 1 tip ( by interfering shoulders 12) tip of the pin 2 and (shoulder 22), it realizes a high torque performance.
[0079]
　Then, as described above, since the shape of the tip portion of the pin 1 (shoulder 12) and pin 2 of the end portion (shoulder 22) is perpendicular to the tube axis CL direction, the leading end portion of the pin 1 (the shoulder 12 ) it is well interfere with the tip of the pin 2 (shoulder 22), can achieve high torque performance.
[0080]
　In the following, refers to a torque in the region REG1 as "thread interference torque", the torque in the region REG2 also referred to as a "shoulder interference torque".
[0081]
　Figure 5 is a longitudinal sectional view of the vicinity of the leading end portion of the pin 1 and 2 of the threaded joint 10 is a diagram showing the deformation behavior of the pin 1 and 2 with the progress of fastening. Referring to the upper part of FIG. 5, when the torque is present in the region REG1 shown in FIG. 4, the threaded joint 10, the distal end portion of the pin 1 (shoulder 12), the tip of the pin 2 in (shoulder 22) not in contact. Torque, caused by the external thread 11 of the pin 1 interferes with the internal thread 31 of the box 3. At this time, the tip portion of the pin 1 and 2, contracts downward by thread interference (see figure upper part of FIG. 5).
[0082]
　Further advancing the clamping, after the pin 1 is in contact with the pin 2, i.e., when torque is present in the region REG2 shown in FIG. 4, a torque, in addition to the external thread 11 of the pin 1 interferes with the internal thread 31 of the box 3 , caused by the tip portion of the pin 1 (shoulder 12) interferes tip of the pin 2 and (shoulder 22). At this time, the interference between the shoulder 12 and 22, reaction force is generated on the contraction in the downward direction by the thread interference (see figure middle of FIG. 5).
[0083]
　Furthermore, when advancing the clamping shoulder 22 of the shoulder 12 and pin 2 of the pin 1, it yields the shoulder compression (see figure lower part of FIG. 5). Depending on the structure of the threaded joint, before the shoulder 12 and 22 to yield, sometimes threaded portion breaks down.
[0084]
　Incidentally, as inferred from Fig. 6A and B, high if order to obtain a torque, male screw and the pin 1 of the tip portion from the torque becomes as large as possible due to interference of the internal thread (shoulder 12) of the pin 2 tip preferably, a structure in contact with (shoulder 22). For example, when used as a threaded joint for oil well pipes having an outer diameter of 5-1 / 2 inches, pin 1 of the tip when it reaches the torque T_Lf when locked flanks (shoulder 12) and the pin 2 tip preferably set the distance d between (shoulder 22) in the range of 1.15 mm ~ 1.55 mm.
[0085]

　Here, the structure shown in FIG. 1 with the steel pipe, i.e., locked in the flank when not in contact tips of pins further the addition of rotary screw portion of the pin prior to surrender structure tip contact each other (hereinafter, referred to as "pin-contact") to prototype threaded joint were measured torque and number of turns of the relationship at the time of fastening. For comparison, by slightly shortening the tip of the pin, before the threaded portion to yield a structure where the tip ends of the pin does not contact (hereinafter, referred to as "no pin contact") to prototype threaded joint, It was subjected to the same measurement. The results are shown in Figure 6A and B.
[0086]
　6A and B are diagrams showing the relationship between the torque and the number of turns due to the presence or absence of the shoulder contact. In FIG. 6A and B, the vertical axis represents torque, and the horizontal axis represents the number of turns.
[0087]
　6A shows a relationship between the torque and the number of turns in the joint without pin contact according to Comparative Example 1. Further, FIG. 6B shows a relationship between the torque and the number of turns in the pin contact has a joint according to the first embodiment.
[0088]
　If no pin contact, torque of the threaded joint were sharply elevated so than there is a number of turns value. More becomes large number of turns, the increase in the degree of torque was reduced (see FIG. 6A).
[0089]
　On the other hand, in the case of there pin contact, the torque of the threaded joint, as in FIG. 6A, abruptly elevated so than there is a number of turns value, further comprising a number number of turns, the increase in the degree of torque was reduced. Torque when the degree of increase of the torque starts to decrease, than without the pin contact was more than 2-fold (see FIG. 6B).
[0090]
　
　also performed machining of the external thread 11 in the threaded joint shown in Figure 1, and measures the processing time. The threaded joint according to the second embodiment, as the external thread 11, to form a thread width variable portion 11A and threaded constant width portion 11B. Tube axis direction of the length of the thread width variable portion 11A and threaded constant width portion 11B are equal. That is half screw constant width portion 111 of the external thread 11. As a result, the external thread 11, the maximum screw Tanihaba became twice the minimum thread root width.
[0091]
　Machining of the external thread 11 was performed using the cutting tool of a size appropriate to the minimum thread root width. As described above, in the external thread 11, the maximum screw Tanihaba is twice the minimum thread root width. Therefore, as one of the cutting path number in the tube axis direction of the screw trough having a minimum thread root width, cutting the number of passes in the tube axis direction of the screw trough having a maximum thread root width (maximum cutting pass number) it became 2. The total cutting pass count in the tube axis direction became 14.
[0092]
　For comparison, we performed processing of the different male thread, and measure the processing time. The threaded joint according to Comparative Example 2, as a male thread, forming only thread width variable portion, did not form a threaded constant width portion. Tube axis direction of the length of the male screw of Comparative Example 2 is substantially equal to the length of the tube axis direction of the external thread 11 according to the second embodiment. Rate of change of the thread root width of the male screw of Comparative Example 2 was also substantially the same as the rate of change of thread root width of the thread width variable portion 11A according to the second embodiment. As a result, the external thread, the maximum screw Tanihaba became 4 times the minimum thread root width.
[0093]
　Processing of external thread was carried out using a cutting tool of a size appropriate to the smallest screw valley width. In male thread, since the maximum screw Tanihaba is four times the minimum thread root width, maximum cutting pass count became 4. The total cutting pass count in the tube axis direction became 28.
[0094]
　(Evaluation)
　FIG. 6C, it shows a graph of machining time according to Example 2 and Comparative Example 2 each of the threaded joint. Maximum cutting pass number and total cutting pass number of the external thread 11 in the second embodiment, respectively, is a half of the maximum cutting pass number and total cutting pass number of the external thread according to Comparative Example 2. Accordingly, as shown in FIG. 7, also the processing time of the external thread 11 according to the second embodiment, which is approximately half of the processing time of the external thread according to Comparative Example 2.
[0095]
　As described above, by providing a threaded constant width section 11B on the external thread 11, as compared to the male screw without the screw constant width portion, it was confirmed that can shorten the processing time of the external thread. For internal thread 31 having a corresponding configuration as the external thread 11 can also be expected a similar effect.
[0096]
　Figure 7 is a longitudinal sectional view of a threaded joint according to a first modification of the first embodiment. Incidentally, FIG. 7, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, the longitudinal sectional view shown in FIG. 7 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0097]
　Referring to FIG. 7, a threaded joint 10A according to a first modification of the first embodiment includes a pin 1A, and 2A, box 3A, and 4A.
[0098]
　Pins 1A, a pair of tubes 6A to be connected, among 7A, is provided in the pipe end portion of one pipe 6A. Pins 2A, a pair of tubes 6A, among 7A, is provided in the pipe end portion of the other pipe 7A.
[0099]
　Box 3A is provided on one end side of the coupling 5A for connecting a pair of tube 6A, the 7A, box 4A is provided at the other end of the coupling 5A.
[0100]
　Pin 1A consists added structural sealing surface 15 (pin side sealing surface) to the pin 1. Sealing surface 15 is disposed between the male thread 11 and the shoulder 12. The seal surface 15 is provided in a tapered shape. Strictly speaking, the sealing surface 15 is obtained by rotating shape composed of a surface corresponding to the peripheral surface of the truncated cone (straight line in longitudinal section diagram shown in FIG. 7), a curve such as an arc around the tube axis CL consists surface corresponding to the peripheral surface of the rotating body shape (in the drawing longitudinal section curve), or have a shape combining them.
[0101]
　Pins 2A consists added structure sealing surface 25 on the pin 2. Sealing surface 25 is disposed between the male thread 21 and the shoulder 22. The sealing surface 25 is provided in a tapered shape. Strictly speaking, the sealing surface 25 is formed of a surface corresponding to the peripheral surface of the rotary body obtained by rotating shape composed of a surface corresponding to the peripheral surface of the truncated cone, a curve such as an arc around the tube axis CL shape, or it has a shape of a combination of these.
[0102]
　Box 3A consists sealing surface 32 corresponds to the sealing surface 15 of the pin 1A (the box side sealing surface) from the additional structure in the box 3. Sealing surface 32 is arranged inside the coupling 5A than the internal thread 31. Sealing surface 32 is provided in a tapered shape. Strictly speaking, the sealing surface 32 is formed of a surface corresponding to the peripheral surface of the rotary body obtained by rotating shape composed of a surface corresponding to the peripheral surface of the truncated cone, a curve such as an arc around the tube axis CL shape, or it has a shape of a combination of these. The shape of the box side sealing surface 32 may be the same shape as the pin side sealing surface 15, may have different shapes. As described above, since the shape of the pin side sealing surface 15 and the box side sealing surface 32 is respectively are three, the combination is nine patterns.
[0103]
　Box 4A consists added structure in correspondence with the sealing surface 25 of the pin 2A the sealing surface 42 in the box 4. Sealing surface 42 is arranged inside the coupling 5A than the internal thread 41. Sealing surface 42 is provided in a tapered shape. Strictly speaking, the sealing surface 42 is formed of a surface corresponding to the peripheral surface of the rotary body obtained by rotating shape composed of a surface corresponding to the peripheral surface of the truncated cone, a curve such as an arc around the tube axis CL shape, or it has a shape of a combination of these. The shape of the box side sealing surface 42 may be the same shape as the pin-side sealing surface 25, may have different shapes. As described above, since the shape of the pin-side sealing surface 25 and the box side sealing surface 42 is respectively are three, the combination is nine patterns.
[0104]
　Sealing surface 15 and 32, along with the screwing of the pin 1A in contact with each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0105]
　Moreover, sealing surfaces 25,42 can, with the screwing of the pin 2A in contact with each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0106]
　Threaded joint 10A also, when the insertion face 111 and the load surface 112 of the external thread 11 of the pin 1A is in contact with the insert surface 311 and load flanks 312 of the internal thread 31 of each box 3A, shoulder 12 (tip) of the pin 1A pin 2A the shoulder 22 not in contact with the (tip), when rotated further in the fastening direction, the shoulder 12 (tip) of the pin 1A before thread (external thread 11 and internal thread 31) is breakdown of pin 2A It has a structure that could be brought into contact with the shoulder 22 (tip).
[0107]
　Accordingly, even in the screw joint 10A, the torque chart shown in FIG. 4 is obtained.
[0108]
　Threaded joint 10A, compared to a threaded joint 10, high sealing performance is obtained by providing the sealing portion. Further, therefore, the sealing performance at the screw portion may be lower than the threaded joint 10.
[0109]
　On the other hand, a threaded joint 10A, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 10, the screw portion is broader possibilities stable torque range performance.
[0110]
　Figure 8 is a longitudinal sectional view of a threaded joint according to a second modification of the first embodiment. Incidentally, FIG. 8, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 8 to the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0111]
　Referring to FIG. 8, a threaded joint 10B according to the second modification of the first embodiment includes a pin 1B, and 2B, box 3B, and 4B.
[0112]
　Pin 1B, a pair of tubes 6B to be connected, among 7B, is provided in the tube end of one pipe 6B. Pin 2B, a pair of tubes 6B, among 7B, is provided in the pipe end portion of the other pipe 7B.
[0113]
　Box 3B is provided on one end side of the coupling 5B for connecting the pair of tube 6B, the 7B, box 4B is provided at the other end of the coupling 5B.
[0114]
　Pin 1B consists added structural sealing surface 16 (pin side sealing surface) to the pin 1. Sealing surface 16 is disposed between the male thread 11 and the base 13. The sealing surface 16 is provided in a tapered shape. Strictly speaking, the sealing surface 16 is formed of a surface corresponding to the peripheral surface of the rotary body obtained by rotating shape composed of a surface corresponding to the peripheral surface of the truncated cone, a curve such as an arc around the tube axis CL shape, or it has a shape of a combination of these.
[0115]
　Pin 2B consists added structural sealing surfaces 26 on the pin 2. Sealing surface 26 is disposed between the male thread 21 and the base 23. The sealing surface 26 is provided in a tapered shape. Strictly speaking, the sealing surface 26 is formed of a surface corresponding to the peripheral surface of the rotary body obtained by rotating shape composed of a surface corresponding to the peripheral surface of the truncated cone, a curve such as an arc around the tube axis CL shape, or it has a shape of a combination of these.
[0116]
　Box 3B consists sealing surface 33 corresponds to the sealing surface 16 of the pin 1B (the box side sealing surface) from the additional structure in the box 3. Sealing surface 33 is disposed on the distal end side of the box 3B than the internal thread 31. Sealing surface 33 is provided in a tapered shape. Strictly speaking, the sealing surface 33 is formed of a surface corresponding to the peripheral surface of the rotary body obtained by rotating shape composed of a surface corresponding to the peripheral surface of the truncated cone, a curve such as an arc around the tube axis CL shape, or it has a shape of a combination of these. The shape of the box side sealing surface 33 may be the same shape as the pin-side sealing surface 16, may have different shapes. As described above, since the shape of the pin-side sealing surface 16 and the box side sealing surface 33 is respectively are three, the combination is nine patterns.
[0117]
　Box 4B consists added structure in correspondence with the sealing surface 26 of the pin 2B the seal surface 43 in the box 4. Sealing surface 43 is disposed on the distal end side of the box 4B than the internal thread 41. Sealing surface 43 is provided in a tapered shape. Strictly speaking, the sealing surface 43 is formed of a surface corresponding to the peripheral surface of the rotary body obtained by rotating shape composed of a surface corresponding to the peripheral surface of the truncated cone, a curve such as an arc around the tube axis CL shape, or it has a shape of a combination of these. The shape of the box side sealing surface 43 may be the same shape as the pin side sealing surface 26, may have different shapes. As described above, since the shape of the pin side sealing surface 26 and the box side sealing surface 43 is respectively are three, the combination is nine patterns.
[0118]
　Sealing surface 16 and 33, along with the screwing of the pin 1B in contact with each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0119]
　Moreover, sealing surfaces 26,43 can, with the threaded pin 2B contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0120]
　Threaded joint 10B also, when the insertion face 111 and the load surface 112 of the external thread 11 of the pin 1B is in contact with the insert surface 311 and load flanks 312 of the internal thread 31 of each box 3B, a shoulder 12 (tip) of the pin 1B pin 2B the shoulder 22 not in contact with the (tip), when rotated further in the fastening direction, the shoulder 12 (tip) of the pin 1B before thread (external thread 11 and internal thread 31) is breakdown of the pin 2B It has a structure that could be brought into contact with the shoulder 22 (tip).
[0121]
　Accordingly, even in the screw joint 10B, the torque chart shown in FIG. 4 is obtained.
[0122]
　Threaded joint 10B as compared to the threaded joint 10, high sealing performance is obtained by providing the sealing portion. Further, therefore, the sealing performance at the screw portion may be lower than the threaded joint 10.
[0123]
　On the other hand, a threaded joint 10B, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 10, the screw portion is broader possibilities stable torque range performance.
[0124]
　Figure 9 is a longitudinal sectional view of a threaded joint according to a third modification of the first embodiment. Incidentally, FIG. 9, of the longitudinal section at the junction of the pair of tubes, shows a longitudinal section view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 9 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0125]
　Referring to FIG. 9, a threaded joint 10C according to a third modification of the first embodiment includes a pin 1C, and 2C, Box 3C, and 4C.
[0126]
　Pin 1C, a pair of tubes 6C coupled, among 7C, provided on the tube end of one pipe 6C. Pins 2C, a pair of tubes 6C, among 7C, provided on the tube end of the other pipe 7C.
[0127]
　Box 3C is provided on one end side of the coupling 5C which connects the pair of tubes 6C, a 7C, Box 4C is provided at the other end of the coupling 5C.
[0128]
　Pin 1C consists added structural sealing surfaces 15 and 16 described above (the pin side sealing surface) to the pin 1.
[0129]
　Pins 2C consists added structural sealing surfaces 25 and 26 as described above to pin 2.
[0130]
　Box 3C consists added structural sealing surface 32, 33 described above (the box side sealing surface) in the box 3.
[0131]
　Box 4C consists added structural sealing surfaces 42, 43 described above in the box 4.
[0132]
　Sealing surface 15 and 32, along with the screwing of the pin 1C contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact. Sealing surfaces 16 and 33 may, in accordance with the screwing of the pin 1C contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0133]
　Moreover, sealing surfaces 25,42 can, with the threaded pin 2C in contact with each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact. Sealing surfaces 26,43 are also in accordance with the screwing of the pin 2C in contact with each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0134]
　Threaded joint 10C also, when the insertion face 111 and the load surface 112 of the external thread 11 of the pin 1C is in contact with the insert surface 311 and load flanks 312 of the internal thread 31 of each box 3C, shoulder 12 (tip) of the pin 1C pin 2C the shoulder 22 not in contact with the (tip), when rotated further in the fastening direction, the shoulder 12 (tip) of the pin 1C before thread (external thread 11 and internal thread 31) is breakdown of the pins 2C It has a structure that could be brought into contact with the shoulder 22 (tip).
[0135]
　Accordingly, even in the threaded joint 10C, the torque chart shown in FIG. 4 is obtained.
[0136]
　Threaded joint 10C, as compared to a threaded joint 10, high sealing performance is obtained by the sealing portion comprises two. Therefore, sealing performance of a screw portion may be lower than the threaded joint 10.
[0137]
　On the other hand, a threaded joint 10C, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 10, the screw portion is broader possibilities stable torque range performance.
[0138]
　Figure 9A is a longitudinal sectional view of an enlarged tip of the pin of a threaded joint according to a fourth modification of the first embodiment. Modification of the fourth, the structure of the distal end portion of the two pins is well different from the first embodiment shown in FIG. 1, the basic structure is the same as in the first embodiment. Also, FIG. 9A shows the stage before engagement completion.
[0139]
　Referring to FIG. 9A, the threaded joint 10D according to a fourth modification of the first embodiment, one of the pins. 1D, the pin female sealing surface 17D formed in the inner circumference of the tip, formed at the tip portion have been and a shoulder 12D. Other pin 2D includes a pin male sealing surface 27D formed on the outer periphery of the distal end portion, and a shoulder surface 22D formed at the tip portion.
[0140]
　More specifically, the pin 1D has a protrusion 19 which extends in the axial direction of the tube than the shoulder 12D. Pin female sealing surface 17D is formed on the inner peripheral surface of the projecting portion 19. Pin female sealing surface 17D is provided in a tapered shape. Strictly speaking, the pin female sealing surface 17D is formed of a surface corresponding to the peripheral surface of the rotary body obtained by rotating shape composed of a surface corresponding to the peripheral surface of the truncated cone, a curve such as an arc around the tube axis CL shape, or has a shape of a combination of these.
[0141]
　On the other hand, the pin 2D, pin male sealing surface 27D is disposed between the male thread 21 and the shoulder 22D. Pin male sealing surface 27D is provided in a tapered shape. Strictly speaking, the pin male sealing surface 27D is formed of a surface corresponding to the peripheral surface of the rotary body obtained by rotating shape composed of a surface corresponding to the peripheral surface of the truncated cone, a curve such as an arc around the tube axis CL shape, or has a shape of a combination of these. As described above, since the shape of the pin female sealing surface 17D and the pin male sealing surface 27D are each in triplicate, the combination is nine patterns.
[0142]
　Sealing surfaces 17D and 27D are in accordance with the screwing of the pin 1D and pin 2D in contact with each other, the pin 1D and pin 2D is a later reached at locked flanks each metal in close contact with each other - to form a seal by metal contact.
[0143]
　Threaded joint 10D according to a fourth modification also, when the insertion face 111 and the load surface 112 of the pin 1D of the external thread 11 is in contact with the insert surface 311 and load flanks 312 of the internal thread 31 of each box 3D, the pin 1D shoulder 12D There does not contact the pin 2D of the shoulder 22D, further when rotating the fastening direction, the shoulder 12D of the pin 1D is brought into contact with the pin 2D of the shoulder 22D before thread (external thread 11 and internal thread 31) yields having obtained structure.
[0144]
　Accordingly, even in the threaded joint 10D, the torque chart shown in FIG. 4 is obtained.
[0145]
　Shoulder angle α of the shoulder 22D is set to, for example, 0 ° ~ -20 °. Correspondingly, the shoulder angle α of the shoulder 12D is set to 0 ° ~ + 20 °. The shoulder angle alpha, perpendicular vertical plane to the tube axis CL direction, the angle between the shoulder surface forming a shoulder. Shoulder angle, when the vertical plane passing through the upper end of the shoulder surface (end of the pin outside diameter side), if the lower end of the shoulder surfaces to the vertical plane (the end of the pin inner diameter side) is positioned at the front end side of the pin positive , and the case which is located on the rear end side of the pin (the distal end of the pin opposite) is negative. Shoulder 22D, it is preferable that the slightly become a negative angle. Write shoulder 22D is a negative angle, rather than a right angle (shoulder angle = 0 °), thereby improving the sealing property at the sealing surface.
[0146]
　[Second Embodiment]
　FIG. 10 is a longitudinal sectional view of a threaded joint according to the second embodiment. Incidentally, FIG. 10, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, the longitudinal sectional view shown in FIG. 10 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0147]
　Referring to FIG. 10, the threaded joint 100 according to the second embodiment includes a pin 1, box 3D, and 4D.
[0148]
　Threaded joint 100 is a threaded joint of the coupling type.
[0149]
　For pins 1 and 2 are as described above.
[0150]
　Box 3D is provided on one end side of the coupling 5D connecting a pair of tube 6, Box 4D is provided at the other end of the coupling 5D.
[0151]
　Box 3D consists added structure a shoulder 34 on the box 3. Box 4D consists added structure a shoulder 44 in the box 4.
[0152]
　Shoulder 34 is provided inside the coupling 5D than the internal thread 31. Shoulder 44 is provided inside the coupling 5D than the internal thread 41.
[0153]
　The shape of the shoulder 34, 44 is preferably perpendicular to the tube axis CL direction.
[0154]
　When reached at the time locked flanked by screwing of the pin 1, the distal end portion of the pin 1 (shoulder 12) is not in contact with the shoulder 34 of the box 3D. The addition of further rotated in the fastening direction from the state, the distal end portion of the pin 1 (shoulder 12) contacts the shoulder 34 of the box 3D before thread (external thread 11 and internal thread 31) breaks down.
[0155]
　That is, the tip of the pin 1 (shoulder 12) when the torque is present in the region REG1 shown in FIG. 4, not in contact with the shoulder 34 of the box 3D, when the torque is present in the region REG2 shown in FIG. 4 , in contact with the shoulder 44 of the box 3D.
[0156]
　Thus, the threaded joint 100, the tip portion of the pin 1 when the torque is present in the region REG2 shown in FIG. 4 (shoulder 12) of the pin 2 in a threaded joint 10 the member contacting the distal end portion (shoulder 22) consisting of a structure that was changed to the shoulder 34 of the box 3D from.
[0157]
　Accordingly, even in the threaded joint 100, the torque chart shown in FIG. 4 is obtained.
[0158]
　Incidentally, when reached during locked flanked by screwing of the pin 2, the tip portion of the pin 2 (shoulder 22) is not in contact with the shoulder 44 of the box 4D, adding further rotated in the fastening direction from the time-locked flanks When the tip of the pin 2 (shoulder 22), threaded portion (male thread 21 and internal thread 41) is in contact with the shoulder 44 of the box 4D before breakdown. Thus, the pin 2 and the box 4D constitute a joint having the same structure as the pin 1 and the box 3D.
[0159]
　Figure 11 is a longitudinal sectional view of a threaded joint according to a first modification of the second embodiment. Incidentally, FIG. 11, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 11 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0160]
　Referring to FIG. 11, a threaded joint 100A according to a first modification of the second embodiment is provided with pins 1A, and 2A, box 3E, and 4E.
[0161]
　Pins 1A, for 2A, is as described in FIG.
[0162]
　Box 3E consists added structure sealing surface 32 in the box 3D described in FIG. 10. Sealing surface 32 are provided to correspond to the seal surface 15 of the pin 1A. The sealing surface 32 is provided between the internal thread 31 and the shoulder 34. As a result, box 3E, in order from the one pipe end side of the coupling 5E, consisting female screw 31, placed a sealing surface 32 and shoulder 34 structure.
[0163]
　Box 4E consists added structure sealing surface 42 in the box 4D described in FIG. 10. Sealing surface 42 is provided corresponding to the sealing surface 25 of the pin 2A. The sealing surface 42 is provided between the internal thread 41 and the shoulder 44. As a result, box 4E, in order from the other pipe end of the coupling 5E, consisting female screw 41, placed a sealing surface 42 and the shoulder 44 structure.
[0164]
　The shape of the seal surface 32 and 42, is as described in FIG.
[0165]
　Sealing surface 15 and 32, along with the screwing of the pin 1A in contact with each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0166]
　Moreover, sealing surfaces 25,42 can, with the screwing of the pin 2A in contact with each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0167]
　Shoulder, negative angle slightly (e.g., -5 ° ~ -20 °) preferably forms an. In the form in which there is a sealing surface in the vicinity of the shoulder, is better shoulder is a negative angle, than at right angles, thereby improving the sealing property at the sealing surface.
[0168]
　Threaded joint 100A also when the insertion face 111 and the load surface 112 of the external thread 11 of the pin 1A is in contact with the insert surface 311 and load flanks 312 of the internal thread 31 of each box 3E, the distal end portion of the pin 1A (shoulder 12) is box 3E of not in contact with the shoulder 34, when rotated further in the fastening direction, contacts the threaded portion (male thread 11 and female thread 31) tip of the pin 1A before to yield (shoulder 12) is a shoulder 34 of the box 3E having a can structure.
[0169]
　Accordingly, even in the threaded joint 100A, the torque chart shown in FIG. 4 is obtained.
[0170]
　Threaded joint 100A, compared with the threaded joint 100, high sealing performance is obtained by providing the sealing portion. Further, therefore, the sealing performance at the screw portion may be lower than the threaded joint 100.
[0171]
　On the other hand, a threaded joint 100A, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 100, threaded portion is broader possibilities stable torque range performance.
[0172]
　Incidentally, when reached during locked flanked by screwing the pin 2A, the distal end portion of the pin 2A (shoulder 22) is not in contact with the shoulder 44 of the box 4E, adding further rotated in the fastening direction from the time-locked flanks When the tip of the pin 2A (shoulder 22), threaded portion (male thread 21 and internal thread 41) is in contact with the shoulder 44 of the box 4E before breakdown. Thus, the pin 2A and the box 4E constitute a threaded joint made of the same structure as the threaded joint 100A.
[0173]
　Figure 12 is a longitudinal sectional view of a threaded joint according to a second modification of the second embodiment. Incidentally, FIG. 12, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, the longitudinal sectional view shown in FIG. 12 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0174]
　Referring to FIG. 12, a threaded joint 100B according to a second modification of the second embodiment is provided with pin 1B, and 2B, box 3F, and 4F.
[0175]
　Pin 1B, for 2B, is as described in FIG.
[0176]
　Box 3F is formed by corresponding to the sealing surface 16 of the pin 1B of the sealing surface 33 (box side sealing surface) from the additional structure box 3D described in FIG. 10. Sealing surface 33 is provided corresponding to the sealing surface 16 of the pin 1B. A sealing surface 33 is provided on one pipe end side of the coupling 5F than the internal thread 31. As a result, box 3F includes, in order from one pipe end side of the coupling 5F, made from the sealing surface 33 were arranged internal thread 31 and the shoulder 34 structure.
[0177]
　Box 4F consists sealing surface 43 corresponds to the sealing surface 26 of the pin 2B (the box side sealing surface) from the additional structure in the box 4D described in FIG. 10. Sealing surface 43 is provided corresponding to the sealing surface 26 of the pin 2B. The sealing surface 43 is provided on the other pipe end side of the coupling 5F than the internal thread 41. As a result, box 4F, in order from the other pipe end of the coupling 5F, made from the sealing surface 43 were arranged internal thread 41 and the shoulder 44 structure.
[0178]
　The shape of the seal surface 33 and 43 is as described in FIG.
[0179]
　Sealing surface 16 and 33, along with the screwing of the pin 1B in contact with each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0180]
　Moreover, sealing surfaces 26,43 can, with the threaded pin 2B contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0181]
　Threaded joint 100B also, when the insertion face 111 and the load surface 112 of the external thread 11 of the pin 1B is in contact with the insert surface 311 and load flanks 312 of the internal thread 31 of each box 3F, the distal end portion of the pin 1B (shoulder 12) is box 3F of not in contact with the shoulder 34, when rotated further in the fastening direction, contacts the threaded portion (male thread 11 and female thread 31) tip of the pin 1B before to yield (shoulder 12) is a shoulder 34 of the box 3F having a can structure.
[0182]
　Accordingly, even in the threaded joint 100B, the torque chart shown in FIG. 4 is obtained.
[0183]
　Threaded joint 100B, as compared to threaded joint 100, high sealing performance is obtained by providing the sealing portion. Further, therefore, the sealing performance at the screw portion may be lower than the threaded joint 100.
[0184]
　On the other hand, a threaded joint 100B, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 100, threaded portion is broader possibilities stable torque range performance.
[0185]
　Incidentally, when reached during locked flanked by screwing pin 2B, the distal end portion of the pin 2B (shoulder 22) is not in contact with the shoulder 44 of the box 4F, adding further rotated in the fastening direction from the time-locked flanks When the tip of the pin 2B (shoulder 22), threaded portion (male thread 21 and internal thread 41) is in contact with the shoulder 44 of the box 4F before breakdown. Thus, the pin 2B and box 4F constitute a threaded joint made of the same structure as the threaded joint 100B.
[0186]
　Figure 13 is a longitudinal sectional view of a threaded joint according to a third modification of the second embodiment. Incidentally, FIG. 13, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, the longitudinal sectional view shown in FIG. 13 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0187]
　Referring to FIG. 13, a threaded joint 100C according to a third modification of the second embodiment is provided with a pin 1C, and 2C, boxes 3G, and the 4G.
[0188]
　Pin 1C, for 2C, is as described in FIG.
[0189]
　Box 3G consists added sealing surface 32, 33 in correspondence with the sealing surfaces 15 and 16 of the pin 1C (the box side sealing surface) in the box 3D described in FIG. 10 structure. Sealing surface 32 is provided between the internal thread 31 and the shoulder 34, sealing surface 33 is provided on one pipe end side of the coupling 5G than the internal thread 31. As a result, box 3G, in order from the one pipe end side of the coupling 5G, consists of sealing surface 33, the internal thread 31, arranged a sealing surface 32 and shoulder 34 structure.
[0190]
　Box 4G consists added sealing surface 42, 43 in correspondence with the sealing surfaces 25 and 26 of the pin 2C (the box side sealing surface) in the box 3D described in FIG. 10 structure. Sealing surface 42 is provided between the internal thread 41 and the shoulder 44, sealing surface 43 is provided on the other pipe end side of the coupling 5G. As a result, box 4G, in order from the other pipe end of the coupling 5G, consists of sealing surface 43, the internal thread 41, is arranged a sealing surface 42 and the shoulder 44 structure.
[0191]
　Sealing surface 15 and 32, along with the screwing of the pin 1C contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact. Sealing surfaces 16 and 33 may, in accordance with the screwing of the pin 1C contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0192]
　Moreover, sealing surfaces 25,42 can, with the threaded pin 2C in contact with each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact. Sealing surfaces 26,43 are also in accordance with the screwing of the pin 2C in contact with each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0193]
　Shoulder, negative angle slightly (e.g., -5 ° ~ -20 °) preferably forms an. In the form in which there is a sealing surface in the vicinity of the shoulder, is better shoulder is a negative angle, thereby improving the sealing property at the sealing surface.
[0194]
　Threaded joint 100C also, when the insertion face 111 and the load surface 112 of the external thread 11 of the pin 1C is in contact with the insert surface 311 and load flanks 312 of the internal thread 31 of each box 3G, the tip of the pin 1C (shoulder 12) is box 3G not in contact with the shoulder 34, further when rotating the fastening direction, contacts the threaded portion (male thread 11 and female thread 31) tip of the pin 1C before to yield (shoulder 12) of the box 3G shoulder 34 having a can structure.
[0195]
　Accordingly, even in the threaded joint 100C, the torque chart shown in FIG. 4 is obtained.
[0196]
　Threaded joint 100C, compared with the threaded joint 100, high sealing performance is obtained by the sealing portion comprises two. Therefore, sealing performance of a screw portion may be lower than the threaded joint 100.
[0197]
　On the other hand, a threaded joint 100C, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 100, threaded portion is broader possibilities stable torque range performance.
[0198]
　Incidentally, when reached during locked flanked by screwing the pins 2C, the distal end portion of the pin 2C (shoulder 22) is not in contact with the shoulder 44 of the box 4G, adding further rotated in the fastening direction from the time-locked flanks When the tip of the pin 2C (shoulder 22), threaded portion (male thread 21 and internal thread 41) is in contact with the shoulder 44 of the box 4G before breakdown. Thus, the pin 2C and boxes 4G constitute a threaded joint made of the same structure as the threaded joint 100C.
[0199]
　[Embodiment 3]
　FIG. 14 is a longitudinal sectional view of a threaded joint according to the third embodiment. Incidentally, FIG. 14, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, the longitudinal sectional view shown in FIG. 14 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0200]
　Referring to FIG. 14, a threaded joint 200 according to the third embodiment includes a pin 201, 202, and boxes 203 and 204.
[0201]
　Pin 201, a pair of tubes 210 and 220 to be connected, is provided on the tube end of one pipe 210.
[0202]
　Pin 202, a pair of tubes 210, 220 are provided in the pipe end portion of the other tube 220.
[0203]
　Box 203 is provided on one end side of the coupling 205 which connects the pair of tubes 210 and 220, box 204 is provided at the other end of the coupling 205.
[0204]
　Pin 201 includes, in order from the tip, has an external thread 211, an intermediate shoulder 213, and the external thread 212.
[0205]
　Male screw 211 in the tube axis CL direction, is provided in a tapered shape at the tip end of the pin 201 than the middle shoulder 213 of the pin 201. Male screw 212 in the tube axis CL direction, is provided in a tapered shape between the intermediate shoulder 213 and the base 216. The male screw 211 is provided in a small radius tapered surface than tapered surface external thread 212 is provided.
[0206]
　Intermediate shoulder 213 in the tube axis CL direction, is disposed between the male thread 211 and external thread 212.
[0207]
　Thus, the pin 201 has a screw structure of the two-stage.
[0208]
　Incidentally, the pin 202 has the same structure as the pin 201.
[0209]
　Box 203 includes in order from the inside of the coupling 205, the female screw 231, an intermediate shoulder 233, and the female screw 232. Internal thread 231 is provided corresponding to the external thread 211 of the pin 201. Internal thread 232 is provided corresponding to the external thread 212 of the pin 201. Intermediate shoulder 233 is provided corresponding to the middle shoulder 213 of the pin 201.
[0210]
　Thus, box 203, corresponding to the screw structure of the pin 201 has a screw structure of the two-stage.
[0211]
　Note that box 204 has the same structure as the box 203.
[0212]
　Each of the external thread 211 and 212 of pin 201 has the same structure as the male thread 11 described above. Thus, each of the external thread 211 and 212, and a threaded width variable portion 11A and threaded constant width portion B, having the shape of a wedge screw (see FIG. 2).
[0213]
　Each internal thread 231 of the box 203 has the same structure as the internal thread 31 described above.
[0214]
　In a threaded joint 200, the external thread 211 has a chamfer surface 211c, the male screw 212 has a chamfer surface 212c, the internal thread 231 has a chamfer surface 231c, the internal thread 232 have a chamfer surface 232c preferable. Chamfer surface 211c, 212c is the same as chamfer surface 11c as described above, chamfer surfaces 231c, 232c is the same as the chamfer surface 31c as described above. By providing the chamfer surface, the insertion of the pin is facilitated, sealability in the screw portion is improved.
[0215]
　Female thread 231 of the male thread 211 and the box 203 of the pin 201 is fastened by screwed together. Also, internal thread 232 of the male thread 212 and the box 203 of the pin 201 is fastened by screwed together.
[0216]
　External thread 211 is screwed into the female screw 231, when the external thread 212 is screwed into the female screw 232, an intermediate shoulder 213 of the pin 201, when locked flanks, not in contact with the intermediate shoulder 233 of the box 203. The addition of rotating further fastening direction from the state, the intermediate shoulder 213 of the pin 201 is threaded portion (male thread 211, 212 and internal thread 231, 232) is in contact with the intermediate shoulder 233 of the box 203 prior to breakdown.
[0217]
　Shape of the intermediate shoulder 233 of the intermediate shoulder 213 and box 203 of the pin 201 is preferably perpendicular to the tube axis CL direction.
[0218]
　15A and B are vertical cross-sectional view of the threaded joint 200 shown in Figure 14 when the thread interference torque and shoulder interference torque is obtained.
[0219]
　Referring to FIG. 15A, when the thread interference torque is obtained, i.e., when the insertion face 111 and the load surface 212 of the male thread 211 and 212 in contact with the insert surface 311 and load flanks 312 of the internal thread 231 and 232 respectively Box 203 in a threaded joint 200, an intermediate shoulder 213 of the pin 201 is not in contact with the intermediate shoulder 233 of the box 203. The distance between the intermediate shoulder 213 and the intermediate shoulder 233 is a d described above. In this case, the tip portion of the pin 201 is not in contact with the tip of the pin 202.
[0220]
　On the other hand, referring to FIG. 15B, when the shoulder interference torque is obtained, the threaded joint 200, an intermediate shoulder 213 of the pin 201, box before threaded portion (male thread 211, 212 and internal thread 231, 232) breaks down 203 It is in contact with the intermediate shoulder 233. Again, the tip portion of the pin 201 is not in contact with the tip of the pin 202.
[0221]
　Therefore, a threaded joint 200, when the insertion face 111 and the load surface 112 of the external thread 211 and 212 of the pin 201 is in contact with the insert surface 311 and load flanks 312 of the internal thread 231 and 232 respectively box 203, the pin 201 intermediate the shoulder 213 box, is not in contact with the intermediate shoulder 233 of the box 203, when rotated further in the fastening direction, an intermediate shoulder 213 of the pin 201 before the threaded portion (male thread 211, 212 and internal thread 231, 232) is breakdown having a structure capable of contact with the intermediate shoulder 233 of 203.
[0222]
　As a result, even in the threaded joint 200, the torque chart shown in FIG. 4 is obtained.
[0223]
　Thus interfere, in a threaded joint 200, torque, in the region REG1 from the torque T_Lf when locked flank to shouldering torque T_sh, external thread 211 of the pin 201 and the internal thread 231 and 232 respectively Box 203 elevated, the shouldering torque T_sh more regions REG2, an intermediate shoulder 213 of the pin 201 interferes with the intermediate shoulder 233 of the box 203 prior to threaded portion (male thread 211, 212 and internal thread 231, 232) breaks down by It increased by.
[0224]
　Therefore, a threaded joint 200, an intermediate shoulder 213 of the pin 201 before the threaded portion (male thread 211, 212 and internal thread 231, 232) breaks down in contact with the intermediate shoulder 233 of the box 203, an intermediate shoulder 213 of the pin 201 box by interfering with the intermediate shoulder 233 of 203 realizes a high torque performance.
[0225]
　Then, as described above, the shape of the intermediate shoulder 233 of the intermediate shoulder 213 and box 203 of the pin 201 are the right angles to the tube axis CL direction, an intermediate shoulder 213 of the pin 201 is in the middle shoulder 233 of the box 203 well interference, it is possible to easily realize the high torque performance.
[0226]
　Incidentally, the pin 202 is also when screwed into the box 204, thread interference torque and shoulder interference torques as if the pin 201 is screwed into the box 203 is obtained.
[0227]
　Figure 16 is a longitudinal sectional view of a threaded joint according to a first modification of the third embodiment. Incidentally, FIG. 16, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, the longitudinal sectional view shown in FIG. 16 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0228]
　Referring to FIG. 16, a threaded joint 200A according to a first modification of the third embodiment includes a pin 201A, and 202A, Box 203A, and 204A.
[0229]
　Pins 201A, a pair of tubes 210A to be connected, out of the 220A, is provided in the pipe end portion of one pipe 210A.
[0230]
　Pins 202A, a pair of tubes 210A to be connected, out of the 220A, is provided in the pipe end portion of the other pipe 220A.
[0231]
　Box 203A, a pair of tubes 210A, provided on one end side of the coupling 205A for connecting 220A, Box 204A is provided at the other end of the coupling 205A.
[0232]
　Pin 201A is made of sealing surface 217 (pin side sealing surface) from the additional structure to the pin 201. Sealing surface 217 is disposed on the distal end side of the pin 201A than the male screw 211. The sealing surface 217 is provided in a tapered shape. Strictly speaking, the sealing surface 217 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0233]
　It should be noted that the pin 202A has the same structure as the pin 201A.
[0234]
　Box 203A consists sealing surface 234 corresponding to the sealing surface 217 of the pin 201A (the box side sealing surface) from the additional structure to box 203. Sealing surface 234 is disposed inside the coupling 205A than the internal thread 231. The sealing surface 234 is provided in a tapered shape. Strictly speaking, the sealing surface 234 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0235]
　It should be noted that the box 204A has the same structure as the box 203A.
[0236]
　Sealing surface 217,234, along with the screwing of the pin 201A contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0237]
　Threaded joint 200A also in threaded width variable portion 11A of the pin 201A, when the insertion face 111 and the load surface 112 of the male thread 211 and 212 in contact with the insert surface 311 and load flanks 312 of the internal thread 231 and 232 respectively box 203A, the pin intermediate shoulder 213 of 201A is not in contact with the intermediate shoulder 233 of the box 203A, when rotated further in the fastening direction, the intermediate pin 201A before threaded portion (male thread 211, 212 and internal thread 231, 232) is to surrender It has a structure in which shoulder 213 may contact the intermediate shoulder 233 of the box 203A.
[0238]
　Note that in the screw-width variable portion 11A of the pin 202A, when the insertion face 111 and the load surface 112 of the male thread 211 and 212 in contact with the insert surface 311 and load flanks 312 of the internal thread 231 and 232 respectively box 204A, the pins 202A intermediate shoulder 213 is not in contact with the intermediate shoulder 233 of the box 204A, when rotated further in the fastening direction, an intermediate shoulder 213 of pin 202A before threaded portion (male thread 211, 212 and internal thread 231, 232) is breakdown having a structure capable of contact with the intermediate shoulder 233 of the box 204A.
[0239]
　Accordingly, even in the threaded joint 200A, the torque chart shown in FIG. 4 is obtained.
[0240]
　Threaded joint 200A, compared with the threaded joint 200, high sealing performance is obtained by providing the sealing portion. Further, therefore, the sealing performance at the screw portion may be lower than the threaded joint 200.
[0241]
　On the other hand, a threaded joint 200A, when proceed with tightening, there is the seal portion breaks down before the screw portion or the intermediate shoulder portion breaks down. Therefore, towards the threaded joint 200, threaded portion is broader possibilities stable torque range performance.
[0242]
　Figure 17 is a longitudinal sectional view of a threaded joint according to a second modification of the third embodiment. Incidentally, FIG. 17, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, the longitudinal sectional view shown in FIG. 17 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0243]
　Referring to FIG. 17, a threaded joint 200B according to a second modification of the third embodiment includes a pin 201B, and 202B, Box 203B, and 204B.
[0244]
　Pin 201B has a pair of tubes 210B to be connected, of the 220B, it is provided on the tube end of one pipe 210B.
[0245]
　Box 203B, a pair of tubes 210B, provided on one end side of the coupling 205B for connecting 220B.
[0246]
　Pin 201B consists sealing surface 218 (pin side sealing surface) from the additional structure to the pin 201. Sealing surface 218 is disposed between the base 216 of the male screw 212 and the pin 201B. The sealing surface 218 is provided in a tapered shape. Strictly speaking, the sealing surface 218 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0247]
　It should be noted that the pin 202B has the same structure as the pin 201B.
[0248]
　Box 203B consists sealing surface 235 corresponding to the sealing surface 218 of the pin 201B (the box side sealing surface) from the additional structure to box 203. Sealing surface 235 is disposed on one end side of the coupling 205B than the internal thread 232. The sealing surface 235 is provided in a tapered shape. Strictly speaking, the sealing surface 235 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0249]
　It should be noted that, box 204B has the same structure as the box 203B.
[0250]
　Sealing surface 218,235, along with the screwing of the pin 201B contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0251]
　Threaded joint 200B also in threaded width variable portion 11A of the pin 201B, when the insertion face 111 and the load surface 112 of the male thread 211 and 212 in contact with the insert surface 311 and load flanks 312 of the internal thread 231 and 232 respectively box 203B, pin intermediate shoulder 213 of 201B is not in contact with the intermediate shoulder 233 of the box 203B, when rotated further in the fastening direction, the intermediate pin 201B before threaded portion (male thread 211, 212 and internal thread 231, 232) is to surrender It has a structure in which shoulder 213 may contact the intermediate shoulder 233 of the box 203B.
[0252]
　Note that in the screw-width variable portion 11A of the pin 202B, when the insertion face 111 and the load surface 112 of the male thread 211 and 212 in contact with the insert surface 311 and load flanks 312 of the internal thread 231 and 232 respectively box 204B, the pin 202B intermediate shoulder 213 is not in contact with the intermediate shoulder 233 of the box 204B, when rotated further in the fastening direction, an intermediate shoulder 213 of the pin 202B before threaded portion (male thread 211, 212 and internal thread 231, 232) is breakdown having a structure capable of contact with the intermediate shoulder 233 of the box 204B.
[0253]
　Accordingly, even in the threaded joint 200B, the torque chart shown in FIG. 4 is obtained.
[0254]
　Threaded joint 200B, as compared to threaded joint 200, high sealing performance is obtained by providing the sealing portion. Further, therefore, the sealing performance at the screw portion may be lower than the threaded joint 200.
[0255]
　On the other hand, a threaded joint 200B, when proceed with tightening, there is the seal portion breaks down before the screw portion or the intermediate shoulder portion breaks down. Therefore, towards the threaded joint 200, threaded portion is broader possibilities stable torque range performance.
[0256]
　Figure 18 is a longitudinal sectional view of a threaded joint according to a third modification of the third embodiment. Incidentally, FIG. 18, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, the longitudinal sectional view shown in FIG. 18 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0257]
　Referring to FIG. 18, a threaded joint 200C according to a third modification of the third embodiment includes a pin 201C, and 202C, Box 203C, and 204C.
[0258]
　Pin 201C has a pair of tubes 210C coupled, of 220C, is provided in the tube end of one pipe 210C.
[0259]
　Box 203C, a pair of tubes 210C, provided on one end side of the coupling 205C for connecting 220C.
[0260]
　Pin 201C consists added structural sealing surface 217 and 218 described above (pin side sealing surface) to the pin 201. It should be noted that the pin 202C has the same structure as the pin 201C.
[0261]
　Box 203C consists added structural sealing surface 234 and 235 have been described above (box side sealing surface) in the box 203. It should be noted that the box 204C has the same structure as the box 203C.
[0262]
　Sealing surface 217,234, along with the screwing of the pin 201C contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact. Sealing surfaces 218,235 also with the screwing of the pin 201C contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0263]
　Threaded joint 200C is also in threaded width variable portion 11A of the pin 201C, when the insertion face 111 and the load surface 112 of the male thread 211 and 212 in contact with the insert surface 311 and load flanks 312 of the internal thread 231 and 232 respectively box 203C, the pin intermediate shoulder 213 of 201C is not in contact with the intermediate shoulder 233 of the box 203C, when rotated further in the fastening direction, the intermediate pin 201C before threaded portion (male thread 211, 212 and internal thread 231, 232) is to surrender It has a structure in which shoulder 213 may contact the intermediate shoulder 233 of the box 203C.
[0264]
　Note that in the screw-width variable portion 11A of the pin 202C, when the insertion face 111 and the load surface 112 of the male thread 211 and 212 in contact with the insert surface 311 and load flanks 312 of the internal thread 231 and 232 respectively box 204C, the pin 202C intermediate shoulder 213 is not in contact with the intermediate shoulder 233 of the box 204C, when rotated further in the fastening direction, an intermediate shoulder 213 of the pin 202C before threaded portion (male thread 211, 212 and internal thread 231, 232) is breakdown having a structure capable of contact with the intermediate shoulder 233 of the box 204C.
[0265]
　Accordingly, even in the threaded joint 200C, the torque chart shown in FIG. 4 is obtained.
[0266]
　Threaded joint 200C, as compared to the threaded joint 200, high sealing performance is obtained by the sealing portion comprises two. Therefore, sealing performance of a screw portion may be lower than the threaded joint 200.
[0267]
　On the other hand, a threaded joint 200C, when proceed with tightening, there is the seal portion breaks down before the screw portion or the intermediate shoulder portion breaks down. Therefore, towards the threaded joint 200, threaded portion is broader possibilities stable torque range performance.
[0268]
　Screw joint according to the third embodiment, the screw stage of the pin and box may be three or more. In this case, the pin and the box has two or more intermediate shoulder. When the thread interference torque is obtained, i.e., when the insertion surface and the load flanks of the pin external thread is in contact with the insert surface and the load flanks of each box of the female screw, all of the two or more intermediate shoulder pins in any not in contact also of two or more intermediate shoulder box, when the shoulder interference torque is obtained, at least one of the two or more intermediate shoulder of the pin before the threaded portion to yield two or more boxes it may be a structure in contact with at least one intermediate shoulder.
[0269]
　Also, threaded joint according to the third embodiment, in addition to the structure screw stage of the pin and the box is three or more, threaded joint 200A from the screw joint 200 described above, 200B, the same changes and changes to either 200C it may be decorated with a threaded joint.
[0270]
　Fourth Embodiment
　FIG. 19 is a longitudinal sectional view of a threaded joint according to the fourth embodiment. Incidentally, FIG. 19, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 19 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0271]
　Referring to FIG. 19, a threaded joint 300 according to the fourth embodiment includes a pin 301 and a box 302.
[0272]
　Threaded joint 300 is a threaded joint integral scheme.
[0273]
　Pin 301, a pair of tubes 310 and 320 to be connected, is provided on the tube end of one pipe 310. Box 302 of the pair of tubes 310 and 320 are provided in the pipe end portion of the other tube 320.
[0274]
　Pin 301 includes, in order from the distal end side, has a shoulder 3011 and the male screw 3012. Shoulder 3011 is arranged in the distal end portion of the pin 301. Male screw 3012 is provided in a tapered shape between the shoulder 3011 and the base 3013 of the pin 301.
[0275]
　Box 302, in order from the main body of the tube 320 has a shoulder 3021 and the internally threaded 3022. Shoulder 3021 is provided corresponding to the shoulder 3011 of the pin 301. Internal thread 3022 is provided in a tapered shape on the tip portion side of the box 302 than shoulder 3021.
[0276]
　Internal thread 3022 of the external thread 3012 and the box 302 of the pin 301 is fastened by screwed together.
[0277]
　When thread interference torque is obtained, the shoulder 3011 (tip) of the pin 301 is not in contact with the shoulder 3021 of the box 302. Further, when the shoulder interference torque is obtained, the shoulder 3011 (tip) of the pin 301 is threaded portion (male thread 3012 and the internally threaded 3022) contacts the shoulder 3021 of the box 302 prior to breakdown.
[0278]
　The shape of the shoulder 3021 of the shoulder 3011 and the box 302 of the pin 301 is preferably perpendicular to the tube axis CL direction.
[0279]
　Male screw 3012 is composed of the same structure as the male thread 11 described above, the internal thread 3022 has the same structure as the internal thread 31 described above (see FIG. 2).
[0280]
　Thus, the external thread 3012 and the internally threaded 3022, has a screw width variable portion 11A and threaded constant width portion 11B, consists of a screw shape of the wedge.
[0281]
　In a threaded joint 300, the external thread 3012 includes a chamfer surface 3012 c, female screw 3022 preferably has a chamfer surface 3022C. Chamfer surface 3012c is the same as the chamfer surface 11c as described above, the chamfer surface 3022c is the same as the chamfer surface 31c as described above. By providing the chamfer surface, the insertion of the pin is facilitated, sealability in the screw portion is improved.
[0282]
　20A and B are vertical cross-sectional view of the threaded joint 300 shown in Figure 19 when the thread interference torque and shoulder interference torque is obtained.
[0283]
　Referring to FIG. 20A, when the thread interference torque is obtained, i.e., the thread width variable portion 11A of the pin 301, insertion face 311 and the load of the internal thread 3022 of the insertion face 111 and load flanks 212 each box 302 of external thread 3012 when in contact with surface 312, the shoulder 3011 of the pin 301 is not in contact with the shoulder 3021 of the box 302. The distance between the shoulder 3021 of the shoulder 3011 and the box 302 of the pin 301 is d described above.
[0284]
　On the other hand, referring to FIG. 20B, when the shoulder interference torque is obtained, the shoulder 3011 of the pin 301 is threaded portion (male thread 3012 and the internally threaded 3022) is in contact with shoulder 3021 of the box 302 prior to breakdown.
[0285]
　Therefore, a threaded joint 300, when the insertion face 111 and the load surface 112 of the male screw 3012 of the pin 301 is in contact with the insert surface 311 and load flanks 312 of the female screw 3022 of each box 302, the shoulder 3011 of the pin 301 is box 302 shoulder 3021 not in contact with, when rotated further in the fastening direction has a structure in which the shoulder 3011 of the pin 301 may contact a shoulder 3021 of the box 302 prior to threaded portion (male thread 3012 and the internally threaded 3022) breaks down.
[0286]
　Therefore, also in the screw joint 300 in the integral scheme, the torque chart shown in FIG. 4 is obtained.
[0287]
　Figure 21 is a longitudinal sectional view of a threaded joint according to a first modification of the fourth embodiment. Incidentally, FIG. 21, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 21 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0288]
　Referring to FIG. 21, a threaded joint 300A according to a first modification of the fourth embodiment includes a pin 301A, and a box 302A.
[0289]
　Pins 301A, a pair of tubes 310A to be connected, out of the 320A, is provided in the pipe end portion of one pipe 310A.
[0290]
　Box 302A, a pair of tubes 310A, among the 320A, is provided in the pipe end portion of the other pipe 320A.
[0291]
　Pin 301A is made of sealing surface 3014 (pin side sealing surface) from the additional structure to the pin 301. Sealing surface 3014 is provided between the shoulder 3011 and the male screw 3012. The seal surface 3014 is provided in a tapered shape. Strictly speaking, the sealing surface 3014 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0292]
　Box 302A consists sealing surfaces 3024 corresponding to the sealing surface 3014 of the pin 301A (the box side sealing surface) from the additional structure to box 302. Sealing surface 3024 is provided between the internal thread 3022 and the shoulder 3021. Sealing surface 3024 is provided in a tapered shape. Strictly speaking, the sealing surface 3024 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0293]
　Sealing surface 3014,3024, along with the screwing of the pin 301A contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0294]
　Shoulder, negative angle slightly (e.g., -5 ° ~ -20 °) preferably forms an. In the form in which there is a sealing surface in the vicinity of the shoulder, is better shoulder is a negative angle, thereby improving the sealing property at the sealing surface.
[0295]
　Threaded joint 300A also in threaded width variable portion 11A of the pin 301A, when the insertion face 111 and the load surface 112 of the male screw 3012 is in contact with the insert surface 311 and load flanks 312 of the female screw 3022 of each box 302A, the pins 301A shoulder 3011 There does not contact the shoulder 3021 of the box 302A, when rotated further in the fastening direction, the shoulder 3011 of the pin 301A before threaded portion (male thread 3012 and the internally threaded 3022) breaks down comes into contact with the shoulder 3021 of the box 302A having obtained structure.
[0296]
　Accordingly, even in the threaded joint 300A, the torque chart shown in FIG. 4 is obtained.
[0297]
　Threaded joint 300A, compared with the threaded joint 300, high sealing performance is obtained by providing the sealing portion. The seal performance at Therefore threaded portion may be lower than the threaded joint 300.
[0298]
　On the other hand, a threaded joint 300A, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 300, threaded portion is broader possibilities stable torque range performance.
[0299]
　Figure 22 is a longitudinal sectional view of a threaded joint according to a second modification of the fourth embodiment. Incidentally, FIG. 22, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 22 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0300]
　Referring to FIG. 22, a threaded joint 300B according to a second modification of the fourth embodiment includes a pin 301B, and a box 302B.
[0301]
　Pin 301B has a pair of tubes 310B to be connected, of the 320B, are provided on the tube end of one pipe 310B.
[0302]
　Box 302B, a pair of tubes 310B, among 320B, are provided on the pipe end portion of the other pipe 320B.
[0303]
　Pin 301B consists sealing surface 3015 (pin side sealing surface) from the additional structure to the pin 301. Sealing surface 3015 is provided between the external thread 3012 and the base 3013. The seal surface 3015 is provided in a tapered shape. Strictly speaking, the sealing surface 3015 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0304]
　Box 302B consists sealing surfaces 3025 corresponding to the sealing surface 3015 of the pin 301B (the box side sealing surface) from the additional structure to box 302. Sealing surface 3025 is disposed on the distal end side of the box 302B than the internal thread 3022. Sealing surface 3025 is provided in a tapered shape. Strictly speaking, the sealing surface 3025 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0305]
　Sealing surface 3015,3025, along with the screwing of the pin 301B contact each other, and later reached when locked flanks metal in close contact with each other - to form a seal by metal contact.
[0306]
　Threaded joint 300B also in threaded width variable portion 11A of the pin 301B, when the insertion face 111 and the load surface 112 of the male screw 3012 is in contact with the insert surface 311 and load flanks 312 of the female screw 3022 of each box 302B, the pin 301B shoulder 3011 There does not contact the shoulder 3021 of the box 302B, when rotated further in the fastening direction, the shoulder 3011 of the pin 301B before threaded portion (male thread 3012 and the internally threaded 3022) breaks down comes into contact with the shoulder 3021 of the box 302B having obtained structure.
[0307]
　Accordingly, even in the threaded joint 300B, the torque chart shown in FIG. 4 is obtained.
[0308]
　Threaded joint 300B, as compared to threaded joint 300, high sealing performance is obtained by providing the sealing portion. The seal performance at Therefore threaded portion may be lower than the threaded joint 300.
[0309]
　On the other hand, a threaded joint 300B, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 300, threaded portion is broader possibilities stable torque range performance.
[0310]
　Figure 23 is a longitudinal sectional view of a threaded joint according to a third modification of the fourth embodiment. Incidentally, FIG. 23, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 23 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0311]
　Referring to FIG. 23, a threaded joint 300C according to a third modification of the fourth embodiment includes a pin 301C, and a box 302C.
[0312]
　Pin 301C has a pair of tubes 310C coupled, of 320C, is provided in the tube end of one pipe 310C.
[0313]
　Box 302C, a pair of tubes 310C, of ​​320C, is provided in the pipe end portion of the other pipe 320C.
[0314]
　Pin 301C consists added structural sealing surface 3014 and 3015 as described above (pin side sealing surface) to the pin 301.
[0315]
　Box 302C consists added structural sealing surface 3024,3025 described above (the box side sealing surface) in the box 302.
[0316]
　Sealing surface 3014,3024, along with the screwing of the pin 301C contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact. Sealing surfaces 3015,3025 may, with the screwing of the pin 301C contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0317]
　Shoulder, negative angle slightly (e.g., -5 ° ~ -20 °) preferably forms an. In the form in which there is a sealing surface in the vicinity of the shoulder, is better shoulder is a negative angle, thereby improving the sealing property at the sealing surface.
[0318]
　Threaded joint 300C is also in threaded width variable portion 11A of the pin 301C, when the insertion face 111 and the load surface 112 of the male screw 3012 is in contact with the insert surface 311 and load flanks 312 of the female screw 3022 of each box 302C, the pin 301C shoulder 3011 There does not contact the shoulder 3021 of the box 302C, when rotated further in the fastening direction, the shoulder 3011 of the pin 301C before threaded portion (male thread 3012 and the internally threaded 3022) breaks down comes into contact with the shoulder 3021 of the box 302C having obtained structure.
[0319]
　Accordingly, even in the threaded joint 300C, the torque chart shown in FIG. 4 is obtained.
[0320]
　Threaded joint 300C, as compared to the threaded joint 300, high sealing performance is obtained by the sealing portion comprises two. Therefore, sealing performance of a screw portion may be lower than the threaded joint 300.
[0321]
　On the other hand, a threaded joint 300C, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 300, threaded portion is broader possibilities stable torque range performance.
[0322]
　[Embodiment 5]
　FIG. 24 is a longitudinal sectional view of a threaded joint according to the fifth embodiment. Incidentally, FIG. 24, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 24 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0323]
　Referring to FIG. 24, a threaded joint 400 according to the fifth embodiment includes a pin 401 and a box 402.
[0324]
　Threaded joint 400 is a threaded joint integral scheme.
[0325]
　Pin 401, a pair of tubes 410, 420 being connected, is provided on the tube end of one pipe 410. Box 402 of the pair of tubes 410 and 420 are provided in the pipe end portion of the other tube 420.
[0326]
　Pin 401 includes, in order from the distal end side, has an external thread 4012 and a shoulder 4013. Male screw 4012 is provided in a tapered shape between the shoulder 4013 and the distal end portion of the pin 401. Shoulder 4013 is arranged on the body side of the tube 410 than the male screw 4012.
[0327]
　Box 402, in order from the main body of the tube 420, having a female screw 4022 and the shoulder 4023. Internal thread 4022 is provided in a tapered shape between the base 4021 and the shoulder 4023 of the box 402. Shoulder 4023 is provided on the tip portion of the box 402 in response to the shoulder 4013 of the pin 401.
[0328]
　Internal thread 4022 of the external thread 4012 and the box 402 of the pin 401 is fastened by screwed together.
[0329]
　When the screw interference torque is obtained, the shoulder 4013 of the pin 401 is not in contact with the shoulder 4023 of the box 402. Further, when the shoulder interference torque is obtained, the shoulder 4013 of the pin 401 is threaded portion (male thread 4012 and the internally threaded 4022) contacts the shoulder 4023 of the box 402 prior to breakdown.
[0330]
　The shape of the shoulder 4023 of the shoulder 4013 and the box 402 of the pin 401 is preferably perpendicular to the tube axis CL direction.
[0331]
　Male screw 4012 is composed of the same structure as the male thread 11 described above, the internal thread 4022 has the same structure as the internal thread 31 described above (see FIG. 2).
[0332]
　Thus, the external thread 4012 and the internally threaded 4022, has a screw width variable portion 11A and threaded constant width portion 11B, consists of a screw shape of the wedge.
[0333]
　In a threaded joint 400, the external thread 4012 includes a chamfer surface 4012C, female screw 4022 preferably has a chamfer surface 4022C. Chamfer surface 4012c is the same as the chamfer surface 11c as described above, the chamfer surface 4022c is the same as the chamfer surface 31c as described above. By providing the chamfer surface, the insertion of the pin is facilitated, sealability in the screw portion is improved.
[0334]
　25A and B are vertical cross-sectional view of the threaded joint 400 shown in Figure 24 when the thread interference torque and shoulder interference torque is obtained.
[0335]
　Referring to FIG. 25A, when the thread interference torque is obtained, i.e., the thread width variable portion 11A of the pin 401, insertion face 311 and the load of the internal thread 4022 of the insertion face 111 and the load surface 212 of the male screw 4012 each box 402 when in contact with surface 312, the shoulder 4013 of the pin 301 is not in contact with the shoulder 4023 of the box 402. The distance between the shoulder 4023 of the shoulder 4013 and the box 402 of the pin 401 is d described above.
[0336]
　On the other hand, referring to FIG. 25B, when the shoulder interference torque is obtained, the shoulder 4013 of the pin 401 is in contact with shoulder 4023 of the box 402 prior to threaded portion (male thread 4012 and the internally threaded 4022) breaks down.
[0337]
　Therefore, a threaded joint 400, when the insertion face 111 and the load surface 112 of the male screw 4012 of the pin 401 is in contact with the insert surface 311 and load flanks 312 of the female screw 4022 of each box 402, the shoulder 4013 of the pin 401 is box 402 shoulder 4023 not in contact with, when rotated further in the fastening direction has a structure in which the shoulder 4013 of the pin 401 may contact a shoulder 4023 of the box 402 prior to threaded portion (male thread 4012 and the internally threaded 4022) breaks down.
[0338]
　Therefore, also in the screw joint 400 in the integral scheme, the torque chart shown in FIG. 4 is obtained.
[0339]
　Figure 26 is a longitudinal sectional view of a threaded joint according to a first modification of the fifth embodiment. Incidentally, FIG. 26, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 26 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0340]
　Referring to FIG. 26, a threaded joint 400A according to a first modification of the fifth embodiment is provided with the pin 401A, and a box 402A.
[0341]
　Pins 401A, a pair of tubes 410A to be connected, out of the 420A, is provided in the pipe end portion of one pipe 410A.
[0342]
　Box 402A, a pair of tubes 410A, among the 420A, is provided in the pipe end portion of the other pipe 420A.
[0343]
　Pin 401A is made of sealing surface 4014 (pin side sealing surface) from the additional structure to the pin 401. Sealing surface 4014 is provided between the tip portion and the male screw 4012 of the pin 401A. The seal surface 4014 is provided in a tapered shape. Strictly speaking, the sealing surface 4014 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0344]
　Box 402A consists sealing surfaces 4024 corresponding to the sealing surface 4014 of the pin 401A (the box side sealing surface) from the additional structure to box 402. Sealing surface 4024 is provided between the base portion 4021 of the female screw 4022 and the box 402A. Sealing surface 4024 is provided in a tapered shape. Strictly speaking, the sealing surface 4024 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0345]
　Sealing surface 4014,4024, along with the screwing of the pin 401A contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0346]
　Threaded joint 400A also in threaded width variable portion 11A of the pin 401A, when the insertion face 111 and the load surface 112 of the male screw 4012 is in contact with the insert surface 311 and load flanks 312 of the female screw 4022 of each box 402A, the pins 401A shoulder 4013 There does not contact the shoulder 4023 of the box 402A, further when rotating the fastening direction, the shoulder 4013 of the pin 401A contacts the shoulder 4023 of the box 402A before threaded portion (male thread 4012 and the internally threaded 4022) breaks down having obtained structure.
[0347]
　Accordingly, even in the threaded joint 400A, the torque chart shown in FIG. 4 is obtained.
[0348]
　Threaded joint 400A, compared with the threaded joint 400, high sealing performance is obtained by providing the sealing portion. The seal performance at Therefore threaded portion may be lower than the threaded joint 400.
[0349]
　On the other hand, a threaded joint 400A, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 400, threaded portion is broader possibilities stable torque range performance.
[0350]
　Figure 27 is a longitudinal sectional view of a threaded joint according to a second modification of the fifth embodiment. Incidentally, FIG. 27, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, the longitudinal sectional view shown in FIG. 27 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0351]
　Referring to FIG. 27, a threaded joint 400B according to a second modification of the fifth embodiment is provided with pins 401B, and a box 402B.
[0352]
　Pin 401B has a pair of tubes 410B to be connected, of the 420B, it is provided on the tube end of one pipe 410B.
[0353]
　Box 402B, a pair of tubes 410B, among 420B, are provided on the pipe end portion of the other pipe 420B.
[0354]
　Pin 401B consists sealing surface 4015 (pin side sealing surface) from the additional structure to the pin 401. Sealing surface 4015 is provided on the theme manner between the external thread 4012 and the shoulder 4013. Strictly speaking, the sealing surface 4015 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0355]
　Box 402B consists sealing surfaces 4025 corresponding to the sealing surface 4015 of the pin 401B (the box side sealing surface) from the additional structure to box 402. Sealing surface 4025 is provided in a tapered shape between the female screw 4022 and the shoulder 4023. Strictly speaking, the sealing surface 4025 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0356]
　Sealing surface 4015,4025, along with the screwing of the pin 401B contact each other, and later reached when locked flanks metal in close contact with each other - to form a seal by metal contact.
[0357]
　Shoulder, negative angle slightly (e.g., -5 ° ~ -20 °) preferably forms an. In the form in which there is a sealing surface in the vicinity of the shoulder, is better shoulder is a negative angle, thereby improving the sealing property at the sealing surface.
[0358]
　Threaded joint 400B also in threaded width variable portion 11A of the pin 401B, when the insertion face 111 and the load surface 112 of the male screw 4012 is in contact with the insert surface 311 and load flanks 312 of the female screw 4022 of each box 402B, the pin 401B shoulder 4013 There does not contact the shoulder 4023 of the box 402B, further when rotating the fastening direction, the shoulder 4013 of the pin 401B is in contact with shoulder 4023 of the box 402B before threaded portion (male thread 4012 and the internally threaded 4022) breaks down having obtained structure.
[0359]
　Accordingly, even in the threaded joint 400B, the torque chart shown in FIG. 4 is obtained.
[0360]
　Threaded joint 400B, as compared to threaded joint 400, high sealing performance is obtained by providing the sealing portion. Further, therefore, the sealing performance at the screw portion may be lower than the threaded joint 400.
[0361]
　On the other hand, a threaded joint 400B, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 400, threaded portion is broader possibilities stable torque range performance.
[0362]
　Figure 28 is a longitudinal sectional view of a threaded joint according to a third modification of the fifth embodiment. Incidentally, FIG. 28, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 28 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0363]
　Referring to FIG. 28, a threaded joint 400C according to a third modification of the fifth embodiment includes a pin 401C, and a box 402C.
[0364]
　Pin 401C has a pair of tubes 410C coupled, of 420C, is provided in the tube end of one pipe 410C.
[0365]
　Box 402C, a pair of tubes 410C, of ​​420C, is provided in the pipe end portion of the other pipe 420C.
[0366]
　Pin 401C consists added structural sealing surface 4014 and 4015 as described above (pin side sealing surface) to the pin 401.
[0367]
　Box 402C consists added structural sealing surface 4024,4025 described above (the box side sealing surface) in the box 402.
[0368]
　Sealing surface 4014,4024, along with the screwing of the pin 301C contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact. Sealing surfaces 4015,4025 may, with the screwing of the pin 401C contact each other, and later has been reached during locked Frank metal in close contact with each other - to form a seal by metal contact.
[0369]
　Shoulder, negative angle slightly (e.g., -5 ° ~ -20 °) preferably forms an. In the form in which there is a sealing surface in the vicinity of the shoulder, is better shoulder is a negative angle, thereby improving the sealing property at the sealing surface.
[0370]
　Threaded joint 400C is also in threaded width variable portion 11A of the pin 401C, when the insertion face 111 and the load surface 112 of the male screw 4012 is in contact with the insert surface 311 and load flanks 312 of the female screw 4022 of each box 402C, the pin 401C shoulder 4013 There does not contact the shoulder 4023 of the box 402C, further when rotating the fastening direction, the shoulder 4013 of the pin 401C is in contact with shoulder 4023 of the box 402C before threaded portion (male thread 4012 and the internally threaded 4022) breaks down having obtained structure.
[0371]
　Accordingly, even in the threaded joint 400C, the torque chart shown in FIG. 4 is obtained.
[0372]
　Threaded joint 400C, as compared to the threaded joint 400, high sealing performance is obtained by the sealing portion comprises two. Therefore, sealing performance of a screw portion may be lower than the threaded joint 400.
[0373]
　On the other hand, a threaded joint 400C, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 400, threaded portion is broader possibilities stable torque range performance.
[0374]
　Sixth Embodiment
　FIG. 29 is a longitudinal sectional view of a threaded joint according to the sixth embodiment. Incidentally, FIG. 29, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 29 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0375]
　Referring to FIG. 29, a threaded joint 500 according to the sixth embodiment includes a pin 501 and a box 502.
[0376]
　Threaded joint 500 is a threaded joint integral scheme.
[0377]
　Pin 501, a pair of tubes 510 and 520 are connected, is provided in the tube end of one pipe 510.
[0378]
　Box 502, of the pair of tubes 510 and 520 are provided in the pipe end portion of the other tube 520.
[0379]
　Pin 501 includes, in order from the front end portion, having a male screw 5012, an intermediate shoulder 5013 and the male screw 5014.
[0380]
　Male screw 5012 is provided in a tapered shape between the tip portion and the intermediate shoulder 5013 of the pin 501. Intermediate shoulder 5013 is provided between the external thread 5012 and the male screw 5014. Male screw 5014 is provided in a tapered shape between the base 5015 of the intermediate shoulder 5013 and the pin 501.
[0381]
　Thus, the pin 501 is comprised of a screw structure of two stages.
[0382]
　Box 502, in order from the main body of the tube 520 has an internal thread 5022, the intermediate shoulder 5023 and the internally threaded 5024. Internal thread 5022 is provided in a tapered shape between the base 5021 and the intermediate shoulder 5023 of the box 502 corresponds to the male screw 5012 of the pin 501. Intermediate shoulder 5023 is provided between the internal thread 5022 and the female screw 5024 in response to an intermediate shoulder 5013 of the pin 501. Internal thread 5024 is provided in a tapered shape between the tip portion of the intermediate shoulder 5023 and the box 502.
[0383]
　Thus, box 502 is composed of a screw structure of the two-stage corresponds to the screw structure of the pin 501.
[0384]
　Internal thread 5022 of the external thread 5012 and the box 502 of the pin 501 is fastened by screwed together.
[0385]
　Internal thread 5024 of the external thread 5014 and the box 502 of the pin 501 is fastened by screwed together.
[0386]
　Male screw 5012 is screwed into the female screw 5022, when the male screw 5014 is screwed into the female screw 5024, an intermediate shoulder 5013 of the pin 501, when the thread interference torque is obtained, without contact with the intermediate shoulder 5023 of box 502, the shoulder interference torques when the obtained screw portion (male thread 5012,5014 and internal thread 5022,5024) is in contact with the intermediate shoulder 5023 of the box 502 prior to breakdown.
[0387]
　Shape of the intermediate shoulder 5023 of the intermediate shoulder 5013 and box 502 of the pin 501 is preferably perpendicular to the tube axis CL direction.
[0388]
　Even when any of the torque of the thread interference torque and shoulder interference torque is obtained, not the distal end portion of the pin 501 contacts the base 5021 of the box 502, the base 5015 of the pin 501 contacts to the free end portion of the box 502 nor does it.
[0389]
　Each external thread 5012,5014 are made of the same structure as the male thread 11 described above, each of the female screw 5022,5024 it has the same structure as the internal thread 31 described above (see FIG. 2).
[0390]
　Thus, each of the external thread 5012,5014 and the internally threaded 5022,5024 has a threaded width variable portion 11A and threaded constant width portion 11B. Each of the external thread 5012,5014 and the internally threaded 5022,5024 consists thread shape of wedge.
[0391]
　In a threaded joint 500, the external thread 5012 includes a chamfer surface 5012C, male screw 5014 has a chamfer surface 5014C, female screw 5022 has a chamfer surface 5022C, female screw 5024 preferably has a chamfer 5024c . Chamfer surface 5012c, 5014c are the same as chamfer surface 11c as described above, chamfer surfaces 5022c, 5024c are the same as chamfer surface 31c as described above.
[0392]
　By providing the chamfer surface, the insertion of the pin is facilitated, sealability in the screw portion is improved.
[0393]
　30A and B are vertical cross-sectional view of the threaded joint 500 shown in Figure 29 when the thread interference torque or shoulder interference torque is obtained.
[0394]
　Referring to FIG. 30A, when the thread interference torque is obtained, i.e., the thread variable portion 11A, the insertion face 311 and the load surface of the female screw 5022,5024 insertion surface 111 and load flanks 212 each box 502 of external thread 5012,5014 when in contact with 312, an intermediate shoulder 5013 of the pin 501 is not in contact with the intermediate shoulder 5023 of the box 502. The distance between the intermediate shoulder 5023 of the intermediate shoulder 5013 and the box 502 of the pin 501 is d described above.
[0395]
　On the other hand, referring to FIG. 30B, when the shoulder interference torque is obtained, the intermediate shoulder 5013 of the pin 501, the intermediate shoulder 5023 of the box 502 prior to threaded portion (male thread 5012,5014 and internal thread 5022,5024) breaks down We are in contact with each other.
[0396]
　Therefore, a threaded joint 500, when the insertion face 111 and the load surface 112 of the male screw 5012,5014 pin 501 is in contact with the insert surface 311 and load flanks 312 of the female screw 5022,5024 each box 502, the pin 501 intermediate the shoulder 5013 box, is not in contact with the intermediate shoulder 5023 of the box 502, when rotated further in the fastening direction, an intermediate shoulder 5013 of the pin 501 before the threaded portion (male thread 5012,5014 and internal thread 5022,5024) is breakdown having a structure capable of contact with the intermediate shoulder 5023 of 502.
[0397]
　Therefore, also in the screw joint 500 in the integral scheme, the torque chart shown in FIG. 4 is obtained.
[0398]
　Figure 31 is a longitudinal sectional view of a threaded joint according to a first modification of the sixth embodiment. Incidentally, FIG. 31, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 31 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0399]
　Referring to FIG. 31, a threaded joint 500A according to a first modification of the sixth embodiment is provided with the pin 501A, and a box 502A.
[0400]
　Pins 501A, a pair of tubes 510A to be connected, out of the 520A, is provided in the pipe end portion of one pipe 510A.
[0401]
　Box 502A, a pair of tubes 510A, among the 520A, is provided in the pipe end portion of the other pipe 520A.
[0402]
　Pin 501A is made of sealing surface 5016 (pin side sealing surface) from the additional structure to the pin 501. Sealing surface 5016 is provided between the tip portion and the male screw 5012 of the pin 501A. The seal surface 5016 is provided in a tapered shape. Strictly speaking, the sealing surface 5016 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0403]
　Box 502A consists sealing surfaces 5026 corresponding to the sealing surface 5016 of the pin 501A (the box side sealing surface) from the additional structure to box 502. Sealing surface 5026 is provided between the base 5021 and the female screw 5022 of the box 502A. Sealing surface 5026 is provided in a tapered shape. Strictly speaking, the sealing surface 5026 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0404]
　Sealing surface 5016,5026, along with the screwing of the pin 501A contact each other, and later has been reached during locked flanks metal in close contact with each other - to form a seal by metal contact.
[0405]
　Threaded joint 500A also in threaded width variable portion 11A of the pin 501A, when the insertion face 111 and the load surface 112 of the male thread 5012,5014 is in contact with the insert surface 311 and load flanks 312 of the female screw 5022,5024 each box 502A, the pin intermediate shoulder 5013 of 501A is not in contact with the intermediate shoulder 5023 of box 502A, when rotated further in the fastening direction, the intermediate pin 501A before threaded portion (male thread 5012,5014 and internal thread 5022,5024) breaks down It has a structure in which the shoulder 5013 may contact the intermediate shoulder 5023 of box 502A.
[0406]
　Accordingly, even in the threaded joint 500A, the torque chart shown in FIG. 4 is obtained.
[0407]
　Threaded joint 500A, compared with the threaded joint 500, high sealing performance is obtained by providing the sealing portion. The seal performance at Therefore threaded portion may be lower than the threaded joint 500.
[0408]
　On the other hand, a threaded joint 500A, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 500, threaded portion is broader possibilities stable torque range performance.
[0409]
　Figure 32 is a longitudinal sectional view of a threaded joint according to a second modification of the sixth embodiment. Incidentally, FIG. 32, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, the longitudinal sectional view shown in FIG. 32 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0410]
　Referring to FIG. 32, a threaded joint 500B according to a second modification of the sixth embodiment is provided with pins 501B, and a box 502B.
[0411]
　Pin 501B has a pair of tubes 510B to be connected, of the 520B, it is provided on the tube end of one pipe 510B.
[0412]
　Box 502B, a pair of tubes 510B, among 520B, are provided on the pipe end portion of the other pipe 520B.
[0413]
　Pin 501B consists sealing surface 5017 (pin side sealing surface) from the additional structure to the pin 501. Sealing surface 5017 is provided between the base portion 5015 of the male screw 5014 and pin 501B. The seal surface 5017 is provided in a tapered shape. Strictly speaking, the sealing surface 5017 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0414]
　Box 502B consists sealing surfaces 5027 corresponding to the sealing surface 5017 of the pin 501B (the box side sealing surface) from the additional structure to box 502. Sealing surface 5027 is disposed between the tip portion of the female screw 5024 and the box 502B. Sealing surface 5027 is provided in a tapered shape. Strictly speaking, the sealing surface 5027 is rotated shape consisting of a surface corresponding to a peripheral surface of a truncated cone as the distal end side diameter is reduced, or a truncated cone circumferential surface thereof, a curve such as an arc around the tube axis CL They are combined to form a corresponding surface on the peripheral surface of the rotary body obtained Te.
[0415]
　Sealing surface 5017,5027, along with the screwing of the pin 501B contact each other, and later reached when locked flanks metal in close contact with each other - to form a seal by metal contact.
[0416]
　Threaded joint 500B also in threaded width variable portion 11A, when the insertion face 111 and the load surface 112 of the male screw 5012,5014 pin 501B is in contact with the insert surface 311 and load flanks 312 of the female screw 5022,5024 each box 502B, pin intermediate shoulder 5013 of 501B is not in contact with the intermediate shoulder 5023 of box 502B, when rotated further in the fastening direction, the intermediate pin 501B before threaded portion (male thread 5012,5014 and internal thread 5022,5024) breaks down It has a structure in which the shoulder 5013 may contact the intermediate shoulder 5023 of box 502B.
[0417]
　Accordingly, even in the threaded joint 500B, the torque chart shown in FIG. 4 is obtained.
[0418]
　Threaded joint 500B, as compared to threaded joint 500, high sealing performance is obtained by providing the sealing portion. The seal performance at Therefore threaded portion may be lower than the threaded joint 500.
[0419]
　On the other hand, a threaded joint 500B, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 500, threaded portion is broader possibilities stable torque range performance.
[0420]
　Figure 33 is a longitudinal sectional view of a threaded joint according to a third modification of the sixth embodiment. Incidentally, FIG. 33, of the longitudinal section at the junction of the pair of tubes, is a longitudinal sectional view of the upper to the tube axis CL, in fact, a longitudinal sectional view shown in FIG. 33 in the tube axis CL longitudinal sectional view of moving symmetrically against are also present on the lower side of the tube axis CL.
[0421]
　Referring to FIG. 33, a threaded joint 500C according to a third modification of the sixth embodiment includes a pin 501C, and a box 502C.
[0422]
　Pin 501C has a pair of tubes 510C coupled, of 520C, is provided in the tube end of one pipe 510C.
[0423]
　Box 502C, a pair of tubes 510C, of ​​520C, is provided in the pipe end portion of the other pipe 520C.
[0424]
　Pin 501C consists added structural sealing surface 5016,5017 described above (the pin side sealing surface) to the pin 501.
[0425]
　Box 502C consists added structural sealing surface 5026,5027 described above (the box side sealing surface) in the box 502.
[0426]
　Sealing surface 5016,5026, along with the screwing of the pin 501C contact each other, and later reached when locked flanks metal in close contact with each other - to form a seal by metal contact. Sealing surfaces 5017,5027 may, with the screwing of the pin 501C contact each other, and later reached when locked flanks metal in close contact with each other - to form a seal by metal contact.
[0427]
　Threaded joint 500C is also in threaded width variable portion 11A, when the insertion face 111 and the load surface 112 of the male screw 5012,5014 pin 501C is in contact with the insert surface 311 and load flanks 312 of the female screw 5022,5024 each box 502C, the pin intermediate shoulder 5013 of 501C is not in contact with the intermediate shoulder 5023 of the box 502C, when rotated further in the fastening direction, the intermediate pin 501C before threaded portion (male thread 5012,5014 and internal thread 5022,5024) breaks down It has a structure in which the shoulder 5013 may contact the intermediate shoulder 5023 of the box 502C.
[0428]
　Accordingly, even in the threaded joint 500C, the torque chart shown in FIG. 4 is obtained.
[0429]
　Threaded joint 500C, as compared to the threaded joint 500, high sealing performance is obtained by the sealing portion comprises two. Therefore, sealing performance of a screw portion may be lower than the threaded joint 500.
[0430]
　On the other hand, a threaded joint 500C, when proceed with tightening, there is the seal portion breaks down before the screw portion or the shoulder portion breaks down. Therefore, towards the threaded joint 500, threaded portion is broader possibilities stable torque range performance.
[0431]
　Screw joint according to the sixth embodiment, the screw stage of the pin and box may be three or more. In this case, the pin and the box has two or more intermediate shoulder. When the thread interference torque is obtained, i.e., it is inserted surface and the load flanks of the pin external thread is in contact with the insert surface and the load flanks of each box of the female screw, all of the two or more intermediate shoulder pins box not be in contact with any of the two or more intermediate shoulder, when the shoulder interference torque is obtained, when is further rotated in the fastening direction, at least two or more intermediate shoulder of the pin before the threaded portion to yield one need only be a structure in contact with at least one of the two or more intermediate shoulder box.
[0432]
　Also, threaded joint according to the sixth embodiment, in addition to the structure screw stage of the pin and the box is three or more, threaded joint 500A from the screw joint 500 described above, 500B, the same changes and changes to either 500C it may be decorated with a threaded joint.
[0433]
　Figure 34 is a longitudinal sectional view of a trapezoidal thread. Referring to FIG. 34, the external thread 51 has the shape of a trapezoidal thread. The external thread 51 has an insertion face 511 and the load surface 512.
[0434]
　Flank angle θ1 of the insert surface 511 is conformal, flank angle θ2 of the load surface 512 is a negative angle.
[0435]
　Thus, in the trapezoidal threads, the flank angle θ1 of the insert surface 511 is conformal, flank angle θ2 of the load surface 512 is a negative angle. The flank angle θ1 is in the range of 5 ° ~ 30 °, the flank angle θ2 is in the range of 0 ° ~ -15 °. It should be noted that the flank angle θ1 may be the same as the flank angle θ2, may be different.
[0436]
　Figure 35A and B is a longitudinal sectional view of the screw-width variable and threaded constant width portion when used in a threaded joint 10 showing a trapezoidal thread in FIG. Figure 35A shows a longitudinal sectional view of the screw-width variable portion 11A, FIG. 35B shows a longitudinal sectional view of the screw the constant width portion 11B.
[0437]
　In this embodiment, the external thread and internal thread having the shape of a trapezoidal thread may be applied to the threaded portion of each pin 1 and the box 3, 4 of the screw joint 10.
[0438]
　In thread width variable portion 11A, the insertion face 511 and the load surface 512 of the external thread 51, respectively, faces the insertion face 711 and the load surface 712 of the female thread 71, thread crest surface 513 of the external thread 51, the internal thread 71 It faces the thread root bottom surface 713.
[0439]
　Then, when locked flank, insertion face 511 and the load surface 512 of the external thread 51, respectively, in contact with the insert surface 711 and load flanks 712 of the internal thread 71, thread crest surface 513 of the external thread 51, the internal thread 71 in contact with the thread root bottom surface 713. Thus, also in the trapezoidal threads, during locked flank, the external thread 51 of the screw-width variable portion 11A has no gap between the internal thread 71, in contact with the internal thread 71.
[0440]
　In the thread width variable portion 11A, stab lead dS insertion surface 111 is different from the load lead dL of load surface 112.
[0441]
　Also in threaded constant width portion 11B, insertion surface 511 and load flanks 512 of the external thread 51, respectively, face the insertion face 711 and the load surface 712 of the female thread 71, thread crest surface 513 of the external thread 51, thread root of the internal thread 71 and it faces the surface 713.
[0442]
　Then, when locked flank, insertion face 511 of the male thread 51, a gap 60 between the stabbing flanks 711 of the female screw 71, the load surface 512 of the external thread 51 is in contact with the load surface 712 of the internal thread 71, screw crest surface 513 of the external thread 51 is in contact with the thread root bottom surface 713 of the internal thread 71. Thus, also in the trapezoidal threads, during locked flank, the external thread 51 of the screw constant width portion 11B has a gap 60 between the internal thread 71 at the insertion face 511 side.
[0443]
　In the thread width constant portion 11B, stab lead dS insertion face 511 is the same as the load lead dL of load surface 512.
[0444]
　In thread width variable portion 11A and threaded constant width portion 11B, the screw trough bottom 713 of the thread crest surface 513 and the internally threaded 71 of the external thread 51 has a shape composed of a surface corresponding to a cylindrical surface centered axis tube axis CL. Alternatively, thread root bottom surface 713 of the thread crest surface 513 and the internally threaded 71 of the external thread 51 may have a shape composed of a surface corresponding to the peripheral surface of the truncated cone having a central axis tube axis CL.
[0445]
　External thread 51 is preferably provided with a chamfer surface 511c. Chamfer surface 511c is an inclined surface which connects the valley bottom of the insertion face 511 and the male screw 51. Female thread 71 is preferably provided with a chamfer surface 711c corresponding to the chamfer surface 511c of the external thread 51.
[0446]
　In thread width variable portion 11A, at the time locked flank chamfer surface 511c of the external thread 51 is in contact with the chamfer surface 711c of the female screw 71 ((a) refer). In contrast, in the screw constant width portion 11B, at the time locked flank chamfer surface 511c of the external thread 51 does not contact the chamfer surface 711c of the internal thread 71.
[0447]
　By providing the chamfer surface, the insertion of the pin is facilitated, sealability in the screw portion is improved. Angle of chamfer surface 511c is suitably the range of 30 ° ~ 60 ° with respect to the valley bottom of the external thread 51.
[0448]
　As described above, even when using the external thread 51 and internal thread 71 has the shape of a trapezoidal thread, when locked flank, insertion face 511 and load flanks 512 female thread 71 of the respective box of the threaded width variable portion 11A of the male screw 51 contacts the insertion surface and the load surface.
[0449]
　Therefore, when applying respectively a male screw 51 and the female thread 71 has the shape of a trapezoidal thread in the external thread 11 and the internal thread 31 of the threaded joint 10, the threaded joint 10, the insertion surface 511 and load flanks 512 each box 3 of the male thread 51 female thread when in contact with the insertion face and load flanks 71, the pin 1 shoulder 12 (tip) is not in contact with the shoulder 22 of the pin 2 (tip), when rotated further in the tightening direction, the screw portion ( has the structure of pin 1 shoulder 12 (tip portion) which may contact the shoulder 22 (tip) pin 2 before the external thread 51 and internal thread 71) breaks down.
[0450]
　As a result, even when applying respectively the external thread 51 and internal thread 71 has the shape of a trapezoidal thread in the external thread 11 and the internal thread 31 of the threaded joint 10, the threaded joint 10, the torque chart shown in FIG. 4 is obtained.
[0451]
　Further, in this embodiment, a threaded joint 10A an external thread 51 and internal thread 71 has the shape of a trapezoidal thread, 10B, 10C, 100,100A, 100B, 100C, 200,200A, 200B, 200C, 300,300A, 300B , 300C, 400,400A, 400B, 400C, 500,500A, 500B, may be applied to either 500C.
[0452]
　In this case, threaded joints 10A, 10B, 10C, 100,100A, 100B, 100C, 200,200A, 200B, 200C, 300,300A, 300B, 300C, 400,400A, 400B, 400C, 500,500A, 500B, 500C in each, the torque chart shown in FIG. 4 is obtained.
[0453]
　Accordingly, in this embodiment, the external thread and the internal thread may be either of the wedge screw and trapezoidal screw.
[0454]
　Further, in the screw joint 10, external thread 11 described above, it may consist of only a screw width variable portion 11A. Even when no thread constant width portion 11B is provided, torque, with insertion face 111 and the load surface 112 of the male thread 11 is raised by interfering with the insertion face 311 and the load surface 312 of the internal thread 31, respectively, further fastening direction when rotating, further increased by the tip of the pin 1 before thread (external thread 11 and internal thread 31) is yielding interferes with the tip portion of the pin 2, and can obtain a torque in a wide range of it is. Therefore, male thread 11 need only include at least the thread width variable portion 11A. For the same reason, the screw joint 10A, 10B, 10C, 100,100A, 100B, 100C, 200,200A, 200B, 200C, 300,300A, 300B, 300C, 400,400A, 400B, 400C, 500,500A, 500B , in 500C, the external thread 11 need only include at least the thread width variable portion 11A.
[0455]
　In the first embodiment described above, the threaded joint of the coupling type, when the insertion face 111 and the load surface 112 of the external thread 11 of the pin 1 is in contact with the insert surface 311 and load flanks 312 of the internal thread 31 of each box 3, pin shoulder 12 (tip) of 1 is not in contact with the shoulder 22 (tip) pin 2, when rotated further in the fastening direction, before screw portion (male thread 11 adversely internal thread 31) yields shoulder 12 of the pin 1 (tip) has been described threaded joint 10 having a structure that could be brought into contact with the shoulder 22 (tip) pin 2.
[0456]
　In the second embodiment described above, the threaded joint of the coupling type, insertion face 111 and the load surface 112 of the external thread 11 of the pin 1 is in contact with the insert surface 311 and load flanks 312 of the internal thread 31 of each box 3D when, not the pin 1 shoulder 12 (tip) is in contact with the shoulder 34 of the box 3D, when rotated further in the fastening direction, the pin before thread (external thread 11 adversely internal thread 31) breaks down 1 shoulder 12 (tip) has been described threaded joint 100 having a structure may contact the shoulder 34 of the box 3D.
[0457]
　Further, in the third embodiment described above, the threaded joint of the coupling type, insertion face 311 and the load surface of the internal thread 231 of the insert surface 111 and load flanks 112 each box 203 of the external thread 211 and 212 of the pin 201 when in contact with 312, when the intermediate shoulder 213 of the pin 201 is not in contact with the intermediate shoulder 233 of the box 203, which is further rotated in the fastening direction, the screw portion (external thread 211, 212 and internal thread 231, 232) the yield intermediate shoulder 213 of the pin 201 has been described threaded joint 200 having a structure capable of contact with the intermediate shoulder 233 of the box 203 prior to.
[0458]
　Further, in the fourth embodiment described above, the threaded joint integral scheme, insertion face 111 and the load surface 112 of the male screw 3012 of the pin 301 is in contact with the insert surface 311 and load flanks 312 of the female screw 3022 of each box 302 when, when the shoulder 3011 of the pin 301 is not in contact with the shoulder 3021 of the box 302, which is further rotated in the fastening direction, the shoulder 3011 of the pin 301 before the threaded portion (male thread 3012 and the internally threaded 3022) is breakdown box been described threaded joint 300 having a structure may contact the shoulder 3021 of 302.
[0459]
　Further, in the fifth embodiment described above, the threaded joint integral scheme, insertion face 111 and the load surface 112 of the male screw 4012 of the pin 401 is in contact with the insert surface 311 and load flanks 312 of the female screw 4022 of each box 402 when, when the shoulder 4013 of the pin 401 is not in contact with the shoulder 4023 of the box 402, which is further rotated in the fastening direction, the shoulder 4013 of the pin 401 before the threaded portion (male thread 4012 and the internally threaded 4022) is breakdown box been described threaded joint 400 having a structure may contact the 402 shoulder 4023.
[0460]
　Further, in the sixth embodiment described above, the threaded joint integral scheme, insertion face 311 and the load surface of the female screw 5022,50024 insertion face 111 and the load surface 112 of the male screw 5012,5014 pins 501, each box 502 when in contact with 312, when intermediate shoulder 5013 of the pin 501 is not in contact with the intermediate shoulder 5023 of box 502, which is further rotated in the fastening direction, the screw portion (male thread 5012,5014 and internal thread 5022,5024) the yield intermediate shoulder 5013 of the pin 501 has been described threaded joint 500 having a structure capable of contact with the intermediate shoulder 5023 of box 502 before.
[0461]
　Then, the threaded width variable portion 11A, the insertion face 111 and the load surface 112, such as a male screw 11 is in contact with the insert surface 311 and load flanks 312, such as the internal thread 31 of 3 such boxes respectively.
[0462]
　Accordingly, threaded joints according to the present embodiment, a threaded joint for connecting a pipe, comprising a pin having a male thread comprising a thread width variable portion, and a box having a female thread comprising thread width variable portion, male threads, female threads and meshing, when the insertion plane and load flanks of the external thread is in contact with the insert surface and the load flanks of the internal thread, respectively, the shoulder provided on the pin is not in contact with the shoulder provided on the other member, the further fastening direction when rotating, before the threaded portion breaks down, it may have a structure in which a shoulder provided on the pin can contact the shoulder provided on the other member.
[0463]
　If the screw joint has such a structure, when the insertion plane and load flanks of the external thread is in contact with the insert surface and the load flanks of the internal thread, respectively, the shoulder provided on the pin is provided on the other member shoulder not be in contact with also by inserting plane and load flanks of the male thread from interfering with the insertion face and load flanks of the internal thread, respectively, rises along a straight line k2 torque is shown in FIG. 4, it is further rotated in the fastening direction when in, the shoulder provided on the pin before the threaded portion to breakdown into contact with the shoulder provided on the other member, by a shoulder provided on the pin interferes with the shoulder provided on the other member, torque is further increased according to curve k3 shown in FIG. The insertion surface and load flanks of the male threads by contact with insert surfaces and load flanks of the internal thread, respectively, the sealing performance in the screw portion is ensured. As a result, screw joint is because it wider range of torque given performance.
[0464]
　The embodiments disclosed herein are to be considered as not restrictive but illustrative in all respects. The scope of the invention being indicated by the appended claims rather than the description above, and is intended to include all modifications within the meaning and range of equivalency of the claims.
Industrial Applicability
[0465]
　The present invention is applied to a threaded joint.

The scope of the claims
[Requested item 1]
　A threaded joint for connecting a pipe,
　the pin having a wedge-shaped external thread comprising thread width variable portion,
　and a box having a wedge-shaped internal thread comprising thread width variable portion,
　the external thread meshes with the female screw,
　insertion of the external thread when the surface and the load surface is in contact with the insert surface and the load flanks of each said female screw, when the shoulder provided on the pin is not in contact with the shoulder provided on the other member, which is further rotated in the fastening direction , before the threaded portion breaks down, has a structure in which a shoulder provided on the pin can contact the shoulder provided on the other member, a threaded joint.
[Requested item 2]
　In the thread width variable portion, the insertion surface of the external thread, the crest surface and the load surface, the insertion surface of each of said internal thread, in contact with the valley bottom and the load surface, whereby a structure expressing a sealing of the threaded joint and that the screw joint according to claim 1.
[Requested item 3]
　The threaded joint is intended for fastening with a coupling a pair of tubes,
　the pin is provided on the tube end of each tube of the pair of tubes has a shoulder at the distal end,
　the box is provided at both ends of the coupling,
　when the insertion surface and the load flanks of the pin external thread of the pair of tubes is in contact with the insert surface and the load flanks of the internal thread of each of said box, said pair of tubes It not in contact shoulder between the pin is, when rotated further in the fastening direction, before the threaded portion breaks down, has a structure in which the shoulder between the pin of the pair of tubes may contact, according to claim 1 or screw joint according to claim 2.
[Requested item 4]
　Pin one of the pin of the pair of tubes further comprises a pin female sealing surface formed on an inner periphery of the distal end portion, the other pin, the pin male seal surface formed on the outer periphery of the distal end portion further comprising,
　the pin female sealing surface, said pin male sealing surface and the sealing contact, a threaded joint according to claim 3.
[Requested item 5]
　Wherein the distal end of the pin shoulder is provided,
　the box shoulder corresponding to shoulder of the pin is provided on,
　when the insertion surface and the load flanks of the external thread is in contact with the insert surface and the load flanks of each of the female thread , no shoulder of the pin is in contact with the shoulder of the box, when rotated further in the fastening direction, before the threaded portion breaks down, has a structure in which the shoulder of the pin can contact the shoulder of the box , claim 1 or threaded joint according to claim 2.
[Requested item 6]
　It said pin includes a plurality of stages external thread, and an intermediate shoulder which is provided between the external thread of the plurality of stages,
　wherein the box comprises a plurality of stages internal thread, of the pin between the plurality of stages of the internal thread intermediate and an intermediate shoulder which is provided in correspondence with the shoulder,
　the insertion surfaces of the pair of one said external thread of pins provided on the tube end of the tube of the insertion plane and load flanks, respectively the internal thread of the tube and when in contact with the load surface, the intermediate shoulder ends of the pin and the box are not in contact, when rotated further in the fastening direction, before the threaded portion breaks down, an intermediate shoulder between the pin and the box having a structure capable of contacting, threaded joint according to claim 1 or claim 2.
[Requested item 7]
　Shoulder is provided at the distal end portion of the box,
　the pin shoulder corresponding to shoulder of the box is provided on,
　when the insertion surface and the load flanks of the external thread is in contact with the insert surface and the load flanks of each of the female thread , shoulder between the box and the pin is not in contact, when rotated further in the fastening direction, before the threaded portion breaks down, has a structure in which a shoulder between the box and the pin may contact, wherein a threaded joint according to claim 1 or claim 2.
[Requested item 8]
　It said pins, in the tube axis direction, has a pin-side sealing surface located on the tube end side and / or the pipe main body side of the external thread,
　box the box, provided in correspondence with the pin side sealing surface having a side sealing surface,
　the pin-side sealing surface, the contact box side sealing surface and the seal, threaded joint according to any one of claims 1 to 7.
[Requested item 9]
　It said external thread and said internal thread further comprises a threaded constant width portion, a threaded joint according to any one of claims 1 to 8.