TUBE JOINT TECHNICAL FIELD

[0001] The present invention relates to a tube joint used to connect a deformable tube body such as a hose or a tube which is flexible and which is formed of a soft material such as a synthetic resin or rubber.

BACKGROUND ART

[0002] Examples of a conventional tube joint of this type include a tube joint including: a joint main body with, a recessed annular groove which is formed on one side of the joint main body and into which an end of a connection tube can be impacted so that an end surface of an outer wall of the recessed annular groove forms an inward-facing inclined surface, while an inner wall side of the recessed annular groove is extended to form an inner tube, the inner tube including a large number of locking grooves circumferentially formed in an outer circumference surface of the inner tube; a cap nut having a back-side surface forming a reverse inclined surface corresponding to the inclined surface of the joint main body; and a wedge ring that has inclined surfaces formed at opposite ends of the wedge ring and conforming to the inclined surface of the tube main body and the reverse inclined surface of the cap nut, and a dividing groove formed in a penetrating manner and inclined at a given angle to an axial direction, wherein, after an end of the connection tube is inserted into the recessed annular groove, the cap nut is engaged with and tightened on a threaded part of the joint main body in a threadable manner to press the wedge ring between the inclined surface of the joint main body and the opposite reverse inclined surface of the cap nut, so that the wedge ring is contracted inside the dividing groove and a large number of teeth formed on an inner circumference surface of the wedge ring in a protruding manner cut into an outer circumference surface of the connection tube, while an inner circumference surface of the compressed connection tube is impacted into the locking groove in die inner tube (see, for example, Patent Document 1).

[0003] Patent Document 1: Japanese Utility Model Application Publication No. S57-182691

DISCLOSURE OF THE INVENTION

[0004] In such a conventional tube joint, the opposite inclined surfaces move to approach each other to deform the wedge ring by contraction of diameter, bringing the inner circumference surface of the wedge ring into pressure contact with the outer circumference surface of the connection tube. However, when the connection tube is, for example, a hose or a tube made of a synthetic resin and a creep (permanent deformation) phenomenon occurs in the pressure contact part between the connection tube and the wedge ring as a result of temporal changes in the hose or tube to reduce the thickness dimension of the pressure contact part, disadvantageous^, not only the tube body becomes likely to slip out but also a fluid becomes likely to leak from between the connection tube and the wedge ring. To solve these problems, an elastically deformable annular seal member may be provided on the outer circumference surface of the inner tube opposite to the inner circumference surface of the connection tube so that a tip of the annular seal member cuts into the inner circumference surface of the connection tube. However, in this case, the thickness dimension of the inner tube increases by an amount equal to the thickness of the seal member. This disadvantageously reduces the flow through the inner tube and causes contamination due to sludge collected on a step formed between the inner tube and the inner circumference surface of the connection tube.

[0005] An object of the present invention is to solve the problems and to, for example, keep slip-out strength high even if a creep phenomenon occurs in the tube body.

[0006] To achieve the objects, the present invention provides a tube joint including a nipple provided along an inserting space for a flexible tube body, a tubular member provided opposite an outer circumference surface of the nipple across the inserting space for the tube body in a radial direction, and having a first inclined surface formed to have an inside diameter gradually decreasing in an inserting direction of the tube body; a clamping member located opposite the outer circumference surface of the nipple across the inserting space for the tube body in the radial direction and opposite the first inclined surface in the inserting direction of the tube body, and provided to be able to make reciprocate movement in the inserting direction of the tube body relative to the first inclined surface, the clamping member having a second inclined surface having an inside diameter gradually decreasing in a direction opposite to the inserting direction of the tube body; and a sleeve located opposite the outer circumference surface of the nipple across the inserting space for the tube body in the radial direction and provided between the first inclined surface and the second inclined surface so as to be able to make reciprocal movement in the inserting direction of the tube body and to be elastically deformable in the radial direction,

the sleeve being formed so as to be deformed by contraction of diameter as the first inclined surface and the second inclined surface move to approach each other relatively, wherein the first inclined surface of the tubular member has a recessed stopper abutted by a back-side end of the sleeve in the inserting direction of the tube body when the first inclined surface and the second inclined surface move to approach each other relatively, and the back-side end of the sleeve has a step part formed to have a thickness larger than an amount by which the stopper is recessed and to protrude from an inner circumference surface of the tubular member toward the outer circumference surface of the nipple when the back-side end abuts against the stopper, and an annular recessed part is formed in the inner circumference surface of the tubular member which is located further toward me back than the step part in the inserting direction of the tube body, the annular recessed part being formed opposite the inserting space for the tube body in the radial direction so as to communicate with the inserting space, and the annular recessed part is formed to have a diameter larger than an inside diameter of the sleeve during diameter contraction and to annularly deform an outer circumference area of a tip of the tube body in a swelling manner to impact the outer circumference surface area into the annular recessed part as the sleeve is deformed by contraction of diameter.

[0007] According to the present invention characterized as described above, with the tube body inserted in the inserting space for the tube body formed along the outer circumference surface of the nipple, the first inclined surface and the second inclined surface move to approach each other relatively to deform the sleeve by contraction of diameter. Thus, the inner circumference surface of the sleeve partly compressively deforms the outer surface of the tube body, while the outer circumference area of the tip of the tube body is deformed toward the annular recessed part in a swelling manner by an amount equal to the capacity of the compressive deformation and impacted into the annular recessed part.

The outer circumference area of the tip of the tube body deformed in a swelling manner is caught on the step part to hold the tube body as a whole so that the tube body is immovable in the inserting direction U and the opposite direction N. Therefore, slip-out strength can be kept high even if a creep phenomenon occurs in the tube body. As a result, compared to a conventional configuration in which opposite inclined surfaces move to approach each other to deform a wedge ring by contraction of diameter, bringing an inner circumference surface of the wedge ring into pressure contact with an outer circumference surface of a connection tube, the present configuration allows possible slip-out of the tube body to be prevented over a long period regardless of a creep phenomenon, improving safety.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Fig. 1 is a vertical cross sectional view showing a tube joint according to an embodiment of the present invention; Fig. 1(a) shows a first inclined surface and a second inclined surface which have not been moved yet, and Fig. 1(b) is a partly enlarged view showing the first inclined surface and second inclined surface having been moved to approach each other.

Fig. 2 is a perspective view of the tube joint according to the embodiment of the present invention;

Fig. 2(a) is an exploded view of the whole tube joint, and Fig. 2(b) is a perspective view only of a sleeve as seen in an opposite direction.

Fig. 3 is a vertical front view showing a tube joint according to another embodiment of the present invention; Fig. 3(a) shows a first inclined surface and a second inclined surface which have not been moved yet, and Fig. 3(b) is a partly enlarged view showing the first inclined surface and second inclined surface having been moved to approach each other.

Fig. 4 is a vertical front view showing a tube joint according to another embodiment of the present invention; Fig. 4(a) shows a first inclined surface and a second inclined surface which have not been moved yet, and Fig. 4(b) is a partly enlarged view showing the first inclined surface and second inclined surface having been moved to approach each other.

Fig. 5 is a vertical front view showing a tube joint according to another embodiment of the present invention; Fig. 5(a) shows a first inclined surface and a second inclined surface which have not been moved yet, and Fig. 5(b) is a partly enlarged view showing the first inclined surface and second inclined surface having been moved to approach each other. Fig. 6 is a perspective view of the tube joint according to the embodiment of the present invention shown in Fig. 5;

Fig. 6(a) is an exploded view of the whole tube joint, and Fig. 6(b) is a perspective view only of a sleeve as seen in an opposite direction.

PREFERRED EMBODIMENT OF THE INVENTION

[0009] Embodiments of the present surface will be described below in detail based on the drawings. As shown in Figs. 1 to 6, a tube joint A according to the embodiments of the present invention includes, as main components, a nipple 1 provided along an inserting space S for a flexible tube body B, a tubular member 20 provided opposite an outer circumference surface la of the nipple 1 across an inserting space S of the tube body B in a radial direction, a clamping member 30 located opposite the outer circumference surface la of the nipple 1 across the inserting space S for the tube body B in the radial direction and provided so as to be able to make reciprocal movement relative to a first inclined surface 2 in an axial direction of the nipple 1, and a sleeve 4 located opposite the outer circumference surface la of the nipple 1 in the radial direction and provided between the first inclined surface 2 and a second inclined surface 3 so as to be able to make reciprocal movement in the axial direction of the nipple 1 and to be elastically deformable in the radial direction. The tubular member 20 has the first inclined surface 2 formed to have an inside diameter gradually decreasing in the axial direction of the nipple 1.The clamping member 30 has the second inclined surface 3 formed to have an inside diameter gradually decreasing in a direction opposite to the direction in which the inside diameter of the first inclined surface 2 decreases.

[0010] As shown in Fig. 1(a), with the first inclined surface 2 of the tubular member 20 and the second inclined surface 3 of the clamping member 30 spaced from each other in the axial direction of the nipple 1, a connection end Ba located at one end of the tube body B is inserted toward the inserting space S for the tube body B formed like a cylinder along the outer circumference surface la of the nipple 1. Then, as shown in Fig. 1(b), the first inclined surface 2 of the tubular member 20 and the second inclined surface 3 of the clamping member 30 are moved to approach each other relatively to deform the sleeve 4 between the first inclined surface 2 and the second inclined surface 3 by contraction of diameter. In conjunction with this, an inner circumference surface of the sleeve 4 is brought into pressure contact with an outer surface B2 of the connection end Ba of the tube body B inserted in the inserting space S for the tube body B and partly deformed by contraction of diameter. At the same time, an outer circumference area B3 of a tip of the connection end Ba of the tube body B is deformed in a swelling manner to keep the tube body B connected so as to preclude the tube body B from being pulled out in the direction U opposite to the inserting direction N.

[0011] The nipple 1 is formed of, for example, metal such as brass or a hard material such as a hard synthetic resin and shaped like a cylinder having an outside diameter approximately the same as or slightly larger or smaller than the inside diameter of the tube body B described below. Alternatively, the nipple 1 is shaped like a thin cylinder having an outside diameter approximately the same as or slightly larger or smaller than the inside diameter of the tube body B by, for example, molding a plate material formed of a deformable rigid material such as stainless steel by pressing or the like. Moreover, the nipple 1 preferably includes a retaining recessed and protruding part lb formed on the outer circumference surface la and located opposite an inner surface Bl of the connection end Ba of the tube body B and a abutting part lc also formed on the outer circumference surface la near a back-side end in the inserting direction N of the tube body B (hereinafter referred to as the "tube inserting direction N"), the abutting part lc lying opposite a tip surface B4 of the connection end Ba. In illustrated examples, the retaining recessed and protruding part lb is formed like bamboo shoots at an axially intermediate position on the outer circumference surface la of the nipple 1 so that annular recessed parts and an annular protruding parts are arranged alternately and sequentially. Furthermore, although not shown in the drawings, the outer circumference surface la of the nipple 1 may alternatively be formed into a smooth surface.

[0012] The tubular member 20 is shaped like a cylinder having an inside diameter larger than the outside diameter of the tube body B described below and formed outside and integrally with trie nipple 1 so as to provide a double cylinder and thus arranged so as to be immovable in the tube inserting direction N. Alternatively, the tubular member 20 formed separately from the nipple 1 is installed outside the nipple 1 in an inserted manner so as to provide a double cylinder and thus mounted integrally with the nipple 1 so as to be immovable in the tube inserting direction N. The tubular member 20 includes the first inclined surface 2 formed on an inner circumference surface of the tubular member 20 opposite the outer circumference surface la of the nipple 1 and having an inside diameter gradually decreasing in the tube inserting direction N.

[0013] The clamping member 30 is formed of, for example, a rust-resistant metal material such as stainless steel or another rigid material and shaped generally like a cylinder partly having, in an axial direction of the clamping member 30, an inside diameter larger than the outside diameter of the sleeve 4 described below. The clamping member 30 is arranged so as to be able to make reciprocal movement via slide means 31 relative to the nipple 1 side in the tube inserting direction N and a tube slip-out direction U. The slide means 31 is formed over the clamping member 30 and the nipple 1 or the tubular member 20 to support the clamping member 30 so that the clamping member 30 can make reciprocal movement in the tube inserting direction N and tube slip-out direction U with respect to the nipple 1. The clamping member 30 includes, on an inner circumference surface thereof, the second inclined surface 3 that is opposite the first inclined surface 2 in the direction U opposite to the tube inserting direction N (hereinafter referred to as the "tube slip-out direction U") and that has an inside diameter gradually decreasing in the tube slip-out direction U, the second inclined surface 3 being formed so as to oppose the outer circumference surface la of the nipple 1.

Alternatively, the second inclined surface 3 is formed integrally with an inner circumference surface of another member impacted in the inner circumference surface of the clamping member 30 in an inserted manner. Preferably, the second inclined surface 3 has approximately the same inclination angle as that of the first inclined surface 2 formed on the inner circumference surface of the tubular member 20 so as to make that the first inclined surface 2 and the second inclined surface 3 surface-symmetric in the tube inserting direction N and so as to have an inverted V-shaped cross section. Furthermore, in another example, the inclination angle of the first inclined surface 2 may be smaller than the inclination angle of the second inclined surface 3 so that the first inclined surface 2 is substantially parallel to the outer circumference surface la of the nipple 1. Moreover, preferably, the outer circumference surface of the clamping member 30 includes, as a tool engagement part 32 for rotating operation, for example, a plurality of planar parts formed at appropriated intervals in a circumferential direction and with which a tool or the like is engaged or recessed parts and protrusion parts formed by knurling.

[0014] The sleeve 4 is formed generally like a cylinder using an elastically deformable material, for example, a polyacetal resin or any other synthetic resin that is excellent in sliding property and heat resistance. The sleeve 4 is arranged opposite the outer circumference surface la of the nipple 1 across the inserting space S for the tube body B in the radial direction and between the first inclined surface 2 and the second inclined surface 3 so as to be able to make reciprocal movement in the tube inserting direction N and the tube slip-out direction U. Moreover, die sleeve 4 has an elastic deformation part 4a that elastically deforms the sleeve 4 in the radial direction by extension and contraction of diameter, and has an inside diameter set to be approximately the same as or larger than the outside diameter of die tube body B when the diameter of the tube body B is extended and to be smaller than the outside diameter of the tube body B when the diameter of the tube body B is contracted. The sleeve 4 includes, on an outer circumference surface thereof, a first tapered surface 4b located opposite the first inclined surface 2 and having a diameter gradually decreasing in the tube inserting direction N and a second tapered surface 4c located opposite and substantially parallel to the second inclined surface 3 and having a diameter gradually decreasing in die tube slip-out direction U. Preferably, the sleeve 4 as a whole is shaped symmetrically in the tube inserting direction N and the tube slip-out direction U by setting the tube inserting direction N length and inclination angle of the first tapered surface 4b the same as the tube slip-out direction U length and inclination angle of the second tapered surface 4c. Furthermore, in another example, the sleeve 4 as a whole may be shaped asymmetrically in the tube inserting direction N and the tube slip-out direction U by setting the inclination angle of the first tapered surface 4b smaller man the inclination angle of the second tapered surface 4c.

[0015] A specific example of die elastic deformation part 4a is configured such that a cutout part 4al such as a slit or a recess is formed in a part of the sleeve 4 in the axial direction to allow the sleeve 4 to be deformed in a telescopic manner to smoothly extend or contract the diameter of the sleeve 4. With the tapered surface 4b in contact with the first inclined surface 2 and with the reverse tapered surface 4c concurrently in contact with the second inclined surface 3, the first inclined surface 2 and the second inclined surface 3 are moved to approach each other relatively to slide the tapered surface 4b and the reverse tapered surface 4c along the first inclined surface 2 and the second inclined surface 3, respectively, deforming the sleeve 4 as a whole by contraction of diameter. In the illustrated examples, a plurality of slits extending from axial ends of the sleeve 4 in the axial direction is cut out in the sleeve 4 in a staggered manner in the circumferential direction to enable the sleeve 4 to be smoothly deformed all over the axial length of the sleeve 4 by extension and contraction of diameter. Furthermore, although not shown in the drawings, in anotiier example, a plurality of slits extending from one end of the sleeve 4 in the axial direction may be cut out in the sleeve 4 in the circumferential direction, one slit may be cut out in the sleeve 4 so as to extend all over die axial length of the sleeve 4, or a slit shaped like a curve or the like which extends nonlinearly may be formed.

[0016] The sleeve 4 includes, on the inner circumference surface thereof, a projection part 4d having an annular shape or a shape similar to the annular shape which extends in the circumferential direction and protruding toward the outer circumference surface la of the nipple 1 and die inserting space S for the tube body B, and an annular seal member 6 having an inner circumference end 6a protruding beyond a tip of the projection part 4d toward the outer circumference surface la of the nipple 1 and the inserting space S for the tube body B. This preferably allows the projection part 4d and die seal member 6 to cut into the outer surface B2 of me tube body B as the sleeve 4 is deformed by contraction of diameter. Specifically, the first inclined surface 2 of the tubular member 20 and die second inclined surface 3 of the clamping member 30 are moved to approach each odier relatively to deform die sleeve 4 by contraction of diameter to push the projection part 4d and the seal member 6 against the outer surface B2 of the tube body B so mat projection part 4d and the seal member 6 cut into the outer surface B2 of the tube body B. Preferably, a plurality of the projection parts 4d is formed at intervals so as to protrude in the tube inserting direction N and the tube slip-out direction U. In this case, die plurality of projection parts 4d is partly brought into pressure contact with die outer surface B2 of die tube body B and thus compressively deformed as the sleeve 4 as a whole is deformed by contraction of diameter.

Thus, an area of the outer surface B2 of the tube body B deformed in a swelling manner is sandwiched between the projection parts 4d to hold the area in pressure contact with the sleeve 4 even if a creep (permanent deformation) phenomenon occurs in the tube body B. This allows sealability to be kept high. As shown in Fig. 2(a), the seal member 6 is formed like a ring using a compressively deformable material, for example, rubber. The seal member 6 is immovably arranged by impacting an outer circumference part of the seal member 6 into a mounting recessed part 4e formed in the inner circumference surface of the sleeve 4, and is thus positioned such that an inner circumference end 6a of the seal member 6 protrudes toward the outer surface B2 of the tube body B. Moreover, preferably, the inner circumference surface of the seal member 6 is curved to have a cross section shaped generally like a circular arc, and the seal member 6 includes a recessed groove part 6b formed on a surface of the seal member 6 and into which, when the seal member 6 is compressively deformed, the part of the seal member 6 deformed in a swelling manner is placed. In the illustrated examples, a plurality of projection parts 4d is formed on the inner circumference surface of the sleeve 4 so as to protrude in the axial direction of the sleeve 4.

The annular mounting recessed part 4e is formed at an intermediate position of the projection part 4d in the axial direction. An elastically deformable seal member 6, for example, an O ring, is impacted into the annular mounting recessed part 4e to hold the sleeve 4 so that the sleeve 4 is immovable in the axial direction. Furthermore, although not shown in the drawings, in another example, one or both of the projection part 4d and the seal member 6 may be omitted from the inner circumference surface of the sleeve 4 to allow a part or all of the inner circumference surface of the sleeve 4 in the axial direction to be made smooth.

[0017] An annular recessed part 5 is formed at a position further toward the back than the sleeve 4 in the tube inserting direction N so as to lie opposite the inserting space S for the tube body B via a step part 5a in the radial direction and to communicate with the inserting space S for the tube body B. Specifically, the step part 5a is contiguously provided at a back-side end of the sleeve 4 in the tube inserting direction N to form the annular recessed part 5 between the step part 5a and the first inclined surface 2 located further toward the back than the sleeve 4 in the tube inserting direction N, or the step part 5a and the annular recessed part 5 are formed at a back-side end of the first inclined surface 2 in the tube inserting direction N so as to lie contiguously in the tube inserting direction N. The annular recessed part 5 is formed to so as to lie, across the inserting space S for the tube body B, opposite an area of the outer circumference surface la of the nipple 1 located further toward the back than a position opposite to the sleeve 4 in the tube inserting direction N, and so as to communicate with the inserting space S for the tube body B via the step portion 5a.

The annular recessed part 5 is formed to have a diameter larger than the maximum inside diameter of the inner circumference surface during contraction of the diameter of the sleeve 4 or the minimum inside diameter of the first inclined surface 2. An inner side surface of the annular recessed part 5 in the tube slip-out direction U is formed into the step part 5a, which is contiguous with an inner bottom surface of the annular recessed part 5 so that the step part 5a crosses the inner bottom surface generally at right angles. Moreover, the annular recessed part 5 is configured to annularly deform, in a swelling manner, an outer circumference area B3 of a tip of the connection end Ba of the tube body B described below to impact the outer circumference area B3 into the annular recessed part 5 as the sleeve 4 is deformed by contraction of diameter while the first inclined surface 2 of the tubular member 20 and the second inclined surface 3 of the clamping member 30 are moving to approach each other relatively.

[0018] On the other hand, preferably, the tube body B is, for example, a hose or a tube molded using, for example, a soft synthetic resin such as vinyl chloride or a soft material such as silicone rubber or any other rubber, and the inner surface Bl and outer surface B2 of the tube body B are flat. As a specific example of the tube body B, a hose of a single layer structure is used in the illustrated examples. Furthermore, although not shown in the drawings, in another example of the tube body B, many types of tube bodies with different structures may be used as an intermediate layer between a transparent or opaque outer layer and a transparent or opaque inner layer: a laminated hose (blade hose) in which a single or a plurality of synthetic resin blades (reinforced threads) are spirally embedded, a spiral reinforced hose (Fohlen hose) in which a band-like reinforcement material formed of synthetic resin or metal and having a rectangular cross section and a linear reinforcement material with a circular cross section are integrated together by being spirally rolled, and a spiral reinforced hose with a metal wire or a synthetic resin wire is spirally embedded therein.

[0019] The tube joint A according to the embodiments of the present invention operates as follows. As shown in Fig. 1(a), the connection end Ba of the tube body B is inserted into the inserting space S for the tube body B formed along the outer circumference surface la of the nipple 1 until the tip surface B4 of the connection end Ba reaches an area located further toward the back than the fust inclined surface 2 in the tube inserting direction N. Then, as shown in Fig. 1(b), for example, the clamping member 30 is moved in the tube inserting direction N by the slide means 31 to move the first inclined surface 2 and the second inclined surface 3 so that the first inclined surface 2 and the second inclined surface 3 approach each other relatively. Then, the tapered surface 4b and the reverse tapered surface 4c slide on the respective inclined surfaces to gradually deform the sleeve 4 as a whole by contraction of diameter.

[0020] Thus, the inner circumference surface of the sleeve 4 comes into pressure contact with the outer surface B2 of the tube body B to partly compressively deform the outer surface B2 of the tube body B, thus allowing the inner circumference surface of the sleeve 4 to cut into the outer surface B2 of the tube body B. At the same time, the outer circumference area B3 of the tip of the tube body B is deformed toward the annular recessed part 5 in a swelling manner by an amount equal to the capacity of the compressive deformation and thus impacted into the annular recessed part 5. The outer circumference area B3 of the tip deformed in a swelling manner is caught on the step part 5a in die tube slip-out direction U to hold the tube body B as a whole so that the tube body B is immovable in the tube slip-out direction U. Therefore, even if a creep phenomenon results from temporal changes to reduce the thickness dimension of the pressure contact part between the tube body B and the sleeve 4, the outer circumference area B3 of the tip of the tube body B deformed in a swelling manner continues to be caught on the step part 5a, allowing the slip-out strength of me tube body B to be kept high.

[0021] In particular, when the annular seal member 6 is provided on me inner circumference surface of the sleeve 4 so that the inner circumference end 6a protrudes toward the inserting space S for the tube body B, the sleeve 4 is deformed by contraction of diameter as the first inclined surface 2 and me second inclined surface 3 move to approach each other relatively. Thus, the inner circumference end 6a of die seal member 6 protruding from me inner circumference surface of the sleeve 4 cuts into and adheres to the outer surface B2 of the tube body B. Thus, even if a creep phenomenon occurs in the tube body B to reduce the thickness dimension of the pressure contact part between the tube body B and the sleeve 4, sealability can be kept high.

As a result, compared to a conventional configuration in which opposite inclined surfaces move to approach each other to deform a wedge ring by contraction of diameter, bringing an inner circumference surface of the wedge ring into pressure contact with an outer circumference surface of a connection tube, the present configuration allows the joint tube to be held on the tube body B in a closed manner over a long period regardless of a creep phenomenon, improving safety. Moreover, compared to a configuration in which an annular seal member is embedded in the outer circumference surface la of the nipple 1 opposite to the inner surface Bl of the tube body B, the present configuration allows me thickness dimension of the nipple 1 to be reduced to prevent a decrease in flow through the nipple 1. This also precludes a large step from being formed between the nipple 1 and the inner surface B1 of the tube body B, preventing possible contamination resulting from collection of sludge to maintain hygiene over a long period.

[0022] Moreover, when a plurality of the projection parts 4d protruding toward the inserting space S for the tube body B is arranged on the inner circumference surface of the sleeve 4 in the inserting direction N of the tube body B (tube inserting direction) at predetermined intervals, an area B2a of the outer surface B of the tube body B sandwiched between the projection parts 4d is deformed in a swelling manner as the sleeve 4 as a whole is deformed by contraction of diameter while the fust inclined surface 2 and the second inclined surface 3 are moving to approach each other relatively. The area B2a deformed in a swelling manner is sandwiched between the projection parts 4d to prevent the tube body B from moving in the tube slip-out direction U. Furthermore, the pressure contact area between the tube body B and the sleeve 4 is held even if a creep (permanent deformation) phenomenon occurs in the tube body B. Therefore, even if a creep phenomenon occurs in the tube body B, sealability can be kept high. As a result, the tube body B can be prevented from slipping out for a long period regardless of a creep phenomenon, and high sealability can be maintained. Thus, safety can further be improved.

[0023] Furthermore, in a case where the first tapered surface 4b opposite to the first inclined surface 2 and the second tapered surface 4c opposite to the second inclined surface 3 are formed on the outer circumference surface of the sleeve 4 so as to be symmetric in the inserting direction N of the tube body B (tube inserting direction) and the opposite direction (tube slip-out direction) U, if trie sleeve 4 is arranged between the first inclined surface 2 of the tubular member 20 and the second inclined surface 3 of the clamp member 30, the sleeve 4 is deformed by contraction of diameter when the first inclined surface 2 and the second inclined surface 3 move to approach each other relatively regardless of whether the first tapered surface 4b and the second tapered surface 4c are arranged in a forward orientation or a backward orientation. Therefore, the sleeve 4 can be assembled either in the forward orientation or in the backward orientation. This facilitates assembly of the sleeve 4, enabling a reduction in assembly errors. Now, the embodiments of the present invention will be described based on the drawings.

[Embodiment 1]

[0024] Embodiment 1 illustrates a case where the annular recessed part 5 is formed, via the step part 5a, at the back-side end of the sleeve 4 in the tube inserting direction N as shown in Fig. 1(a), Fig. 1(b), and Fig. 2. Specifically, the back-side end surface of the sleeve 4 in the tube inserting direction N is formed into the step part 5a, and the annular recessed part 5 is formed over the tubular member 20 with the first inclined surface 2 adjacent to the step part 5a. As the sleeve 4 is deformed by contraction of diameter, the inner circumference surface of the sleeve 4 is allowed to cut into the outer surface B2 of the tube body B. Then, the outer surface B2 of the compressively deformed tube body B is deformed along the step part 5a corresponding to the back-side end surface of the sleeve 4 so that the resulting diameter of the outer surface B2 is larger than the maximum inside diameter of the inner circumference surface of the inner circumference surface of the sleeve 4 during contraction of diameter.

[0025] Moreover, according to Embodiment 1, threaded parts engaged with each other in a threadable manner are used as the slide means 31 allowing the clamping member 30 to move in the axial direction relative to the nipple 1. In examples illustrated in Fig. 1(a), Fig. 1(b), and Fig. 2, the clamping member 30 forming the second inclined surface 3 is a nut with an internal thread part engraved as the slide means 31. The internal thread part is engaged with an external thread part 21 engraved on an outer circumference surface of the tubular member 20 to mount the clamping member 30 on the nipple 1 side so that the clamping member 30 can make reciprocal movement in the axial direction. The clamping member 30 is rotationally operated to move the second inclined surface 3 closer to the first inclined surface 2 of the tubular member 20 to approximately evenly deform the first tapered surface 4b and second tapered surface 4c of the sleeve 4 by contraction of diameter.

If metal threaded parts engaged with each other in a threadable manner are used as the slide means 31, when both threaded parts are engaged with each other in a threadable manner in conjunction with clamping, heat is generated in the threaded parts as a result of friction. The frictional heat expands both threaded parts, which may then adhere to each other and are inhibited from moving. That is, "galling" may occur. To prevent this, either the internal thread part or the external thread part is preferably formed of nonmetal so as to prevent possible frictional heat in the threaded parts during clamping. In the illustrated examples, the tubular member 20 with the first inclined surface 2 provided thereon is located outside and opposite the nipple 1 across the inserting space S for the tube body B in the radial direction and integrally with the nipple 1 so as to form a double cylinder.

[0026] Moreover, in the examples illustrated in Fig. 1(a) and Fig. 1(b), a protruding part slightly protruding from the outer circumference surface la of the nipple 1 is formed as an abutting part lc opposite to the tip surface B4 of the tube body B. A space in which the tip surface B4 of the tube body B can be deformed is formed outside the protruding part. Furthermore, although not shown in the drawings, in another example, the abutting part lc may be formed to protrude perpendicularly from the outer circumference surface la of the nipple 1 so that the entire tip surface B4 abuts against the abutting part lc when the tube body B is inserted. In Embodiment 1, the mounting recessed part 4e in which the seal member 6 is mounted is integrally formed in the center of the inner circumference surface of the sleeve 4 in the tube inserting direction N and the tube slip-out direction U. A plurality of (two) projection parts 4d is integrally molded on the tube inserting direction N side and on the tube slip-out direction U side across the mounting recessed part 4e. Thus, the sleeve 4 as a whole is shaped symmetrically in the tube inserting direction N and the tube slip-out direction U.

[0027] Moreover, the nipple 1 includes a joint main body 10 formed on the back side of the nipple 1 in the tube inserting direction N. In Embodiment 1, the joint main body 10 includes a threaded part 10a formed integrally with the nipple 1 and via which the tube joint A is connected to a tube connection port (not shown in the drawings) of another device and a tool engagement part 10b formed integrally with the nipple 1 and with which a tool, for example, a spanner or a wrench (not shown in the drawings) is engaged. The threaded part 10a is engaged, in a threadable manner, with a tirreaded part (not shown in the drawings) formed in another line to detachably connect to the tube joint to the device. When an internal thread is engraved in an inner circumference surface of the tube connection port of the device (not shown in the drawings) connected to the tube joint A, the threaded part 10a includes an external thread engaged thereon and corresponding to the internal thread. When an external thread is engraved in an outer circumference surface of the tube connection port of the device, the threaded part 10a includes an internal thread engaged thereon and corresponding to the external thread. In the illustrated examples, an external thread is engraved as the threaded part 10a. As the tool engagement part 10b, a hexagon nut having a larger diameter than a hexagon nut partly formed as a tool engagement part 32 for rotating operation is formed at an axial end of an outer circumference surface of the clamping member 30. Furthermore, although not shown in the drawings, in another example, the direaded part 10a and the tool engagement part 10b may be formed as the joint main body 10 separately from the nipple 1 and detachably mounted over the nipple 1.

[0028] According to the tube joint A according to Embodiment 1 of the present invention, as in the examples illustrated in Fig. 1(a), Fig. 1(b), and Fig. 2, the clamping member 30 is moved in the tube inserting direction N for clamping during threadable engagement in which the clamping member 30 serves as the slide means 31, and the second inclined surface 3 is thus moved to approach the first inclined surface 2 to deform the sleeve 4 by contraction of diameter. Then, the inner circumference surface (the projection part 4d and the seal member 6) of the sleeve 4 is brought into pressure contact with the outer surface B2 of the tube body B to cut into the outer surface B2 of the tube body B while partly compressively deforming the outer surface B2.

At the same time, the inner circumference surface of the sleeve 4 is deformed in a swelling manner along the step part 5a toward the annular recessed part 5 by an amount equal to the capacity of the compressive deformation so that the resulting diameter of the sleeve 4 is larger than the maximum inside diameter of the inner circumference surface during contraction of the diameter of the sleeve 4. Thus, the outer circumference area B3 of the tip of the tube body B deformed in a swelling manner is caught on the step part 5a in the tube slip-out direction U. The tube body B as a whole is then held so as to be immovable in the tube slip-out direction U. Therefore, advantageously, the embodiment can keep slip-out strength high in association with a creep phenomenon of the tube body B in spite of the simple structure of the embodiment.

[0029] Moreover, as in the illustrated examples, if a protruding part protruding slightly from the outer circumference surface la of the nipple 1 is formed as the abutting part lc opposite to the tip surface B4 of the tube body B, when the inner circumference surface of the sleeve 4 cuts into the outer surface B2 of the tube body B, the tip surface B4 of the tube body B is deformed, in a swelling manner, toward the back side in the tube inserting direction N, of the protruding part serving as the abutting part lc. Thus, advantageously, the inner circumference surface of the sleeve 4 can further be clamped against the outer surface B2 of the tube body B to cut more deeply into the outer surface B2.

[Embodiment 2]

[0030] As shown in Fig. 3(a) and Fig. 3(b), Embodiment 2 is different from Embodiment 1 illustrated in Fig. 1(a), Fig. 1(b), and Fig. 2 in that the annular recessed part 5 is formed, via the step part 5a, at the back-side end of the first inclined surface 2 of the tubular member 20 in the tube inserting direction N, and is the same as Embodiment 1 illustrated in Fig. 1(a), Fig. 1(b), and Fig. 2 in regard to the remaining part of the configuration. Specifically, the step part 5a and the annular recessed part 5 are formed in the tubular member 20 contiguously with the back-side end of the first inclined surface 2. The inner circumference surface of the sleeve 4 is brought into pressure contact with the outer surface B2 of the tube body B as the sleeve 4 is deformed by contraction of diameter. Then, the outer surface B2 of the compressively deformed tube body B is deformed, in a swelling manner, along the step part 5a corresponding to the back-side end of the first inclined surface 2 so that the resulting diameter of the outer surface B2 is larger than the minimum inside diameter of the first inclined surface 2.

[0031] In examples illustrated in Fig. 3(a) and Fig. 3(b), inside the tubular member 20 formed outside and integrally with the nipple 1, a separately formed cylindrical member 22 is fitted in an inserted manner so as to be immovable in the tube inserting direction N. Thus, the first inclined surface 2 formed on an inner circumference surface of the cylindrical member 22 is arranged opposite the outer circumference surface la of the nipple 1 across the inserting space S for the tube body B in the radial direction.

[0032] According to the tube joint A according to Embodiment 2 of the present invention, as in the examples illustrated in Fig. 3(a) and Fig. 3(b), the clamping member 30 is moved in the tube inserting direction N for clamping during threadable engagement in which the clamping member 30 serves as the slide means 31, and the second inclined surface 3 is thus moved to approach the fust inclined surface 2 to deform the sleeve 4 by contraction of diameter. Then, the inner circumference surface (the projection part 4d and the seal member 6) of the sleeve 4 is brought into pressure contact with the outer surface B2 of the tube body B to cut into the outer surface B2 of the tube body B, thus partly compressively deforming the outer surface B2. At the same time, the inner circumference surface of the sleeve 4 is deformed in a swelling manner along the step part 5a toward the annular recessed part 5 by an amount equal to the capacity of the compressive deformation so that the resulting diameter of the sleeve 4 is larger than the maximum inside diameter of the first inclined surface 2.

Thus, the outer circumference area B3 of the tip of the tube body B deformed in a swelling manner is caught on the step part 5a in the tube slip-out direction U. The tube body B as a whole is then held so as to be immovable in the tube slip-out direction U. Thus, compared to Embodiment 1 shown in Fig. 1(a), Fig. 1(b), and Fig. 2, Embodiment 2 advantageously allows the outer circumference area B3 of the tip of the tube body B fitted in the annular recessed part 5 to be deformed in a swelling manner by a constant amount regardless of the amount by which the inner circumference surface (the projection part 4d and the seal member 6) of the sleeve 4 cuts into the outer surface B2 of the tube body B. This allows slip-out strength to be kept high in association with a creep phenomenon of the tube body B.

[Embodiment 3]

[0033] As shown in Fig. 4(a) and Fig. 4(b), Embodiment 3 is different from Embodiment 1 shown in Fig. 1(a), Fig. 1(b), and Fig. 2 and Embodiment 2 shown in Fig. 3(a) and Fig. 3(b) in that the first inclined surface 2 is provided with a stopper 2a against which a back-side end 4f of the sleeve 4 in the inserting direction (tube inserting direction) N of the tube body B abuts when the first inclined surface 2 and the second inclined surface 3 move to approach each other relatively so that the stopper 2a of the first inclined surface 2 and the back-side end 4f of the sleeve 4 are allowed to abut against each other when the first inclined surface 2 and the second inclined surface 3 are moved by the clamping member 30 so as to approach each other relatively and so that the second tapered surface 4c opposite to the second inclined surface 3 is deformed by contraction of diameter most significantly in the sleeve 4. Embodiment 3 is the same as Embodiment 1 shown in Fig. 1(a), Fig. 1(b), and Fig. 2 and Embodiment 2 shown in Fig. 3(a) and Fig. 3(b) in regard to the remaining part of the configuration.

Specifically, the stopper 2a opposite to the back-side end 4f of the sleeve 4 in the tube inserting direction N is formed as a recess near the back-side end of the first inclined surface 2 in the tube inserting direction N. As the clamping member 30 is operated to relatively move the first inclined surface 2 and the second inclined surface 3 closer to each other, first, the sleeve 4 is deformed by contraction of diameter, while moving in the tube inserting direction N. Then, the back-side end 4f of the sleeve 4 in the tube inserting direction N abuts against the stopper 2a. Subsequently, with the back-side end 4f of the sleeve 4 in the tube inserting direction N abutting against the stopper 2a, the clamping member 30 is further operated to move the second inclined surface 3 closer to the fust inclined surface 2 of the tubular member 20 so that the second inclined surface 3 mainly deforms the second tapered surface 4c most significantly in the sleeve 4.

[0034] In examples illustrated in Fig. 4(a) and Fig. 4(b), the sleeve 4 is used which is formed to make the first tapered surface 4b and the second tapered surface 4c are symmetric in the tube inserting direction N and the tube slip-out direction U. The clamping member 30 is rotationally operated to move the second inclined surface 3 closer to the first inclined surface 2, first, the sleeve 4 is deformed by contraction of diameter, while moving in the tube inserting direction N, with the back-side end 4f of the sleeve 4 in the tube inserting direction N abutting against the stopper 2a as shown in Fig. 4(b). Subsequently, when the clamping member 30 is rotationally operated to move the second inclined surface 3 closer to the first inclined surface 2, the second inclined surface 3 presses not only the second tapered surface 4c of the sleeve 4 but also the entire sleeve 4 other than the first tapered surface 4b, that is, approximately the entire outer circumference surface of the elastic deformation part 4a so as to incline the second tapered surface 4c and the outer circumference surface in a straight line along the second inclined surface 3. In other words, the second inclined surface 3 is deformed by contraction of diameter more significantly than the first tapered surface 4b of the sleeve 4, and the inner circumference part of the second tapered surface 4c and the annular seal member 6 are deformed by contraction of diameter most significantly.

Thus, the inner circumference area of the second tapered surface 4c comes into pressure contact with the outer surface B2 of the tube body B to cut into the outer surface B2 most deeply in the sleeve 4. The outer surface B2 of the tube body B clamps, in a concentrative manner, the inner circumference area of the second tapered surface 4c and an area of the second tapered surface 4c which comes into contact with the annular seal member 6. Furthermore, although not shown in the drawings, in another example, the sleeve 4 may also be used which is formed to be asymmetric in the tube inserting direction N and the tube slip-out direction U, wherein the inclination angle of the first inclined surface 2 is set smaller than the inclination angle of the second inclined surface 3 so as to make the first inclined surface 2 approximately parallel to the outer circumference surface la of the nipple 1 and the inclination angle of the first tapered surface 4b is smaller than the inclination angle of the second tapered surface 4c.

[0035] Moreover, in the examples illustrated in Fig. 4(a) and Fig. 4(b), a transparent window 2b is provided on an area of the tubular member 20 which corresponds, in the radial direction, to the abutting part lc formed on the outer circumference surface la of the nipple 1 to allow visual check of whether or not the tip surface B4 of the tube body B has reliably abutted against the abutting part lc formed on the outer circumference surface la of the nipple 1. When the slide means (internal thread part) 31 of the clamping member 30 is engaged with the external thread part 21 of the tubular member 20 in a threadable manner to clamp the tubular member 20, the transparent window 2b is covered with the clamping member 30 and prevented from being exposed as shown in Fig. 4(b). Furthermore, in the examples illustrated in Fig. 4(a) and Fig. (b), the retaining recessed and protruding part lb is arranged at a position on the nipple 1 opposite to the inner circumference area of the second tapered surface 4c and the annular seal member 6.

[0036] According to the tube joint A according to Embodiment 3 of the present invention, when the first inclined surface 2 and the second inclined surface 3 are moved by the clamping member 30 to approach each other relatively, the back-side end 4f of the sleeve 4 in the tube inserting direction N is allowed to abut against the stopper 2a, inhibiting the sleeve 4 from further moving. As the second inclined surface 3 subsequently moves to approach the first inclined surface 2, the second tapered surface 4c opposite to the second inclined surface 3 is deformed by contraction of diameter most significantly in the sleeve 4, with the inner circumference area of the second tapered surface 4c coming into pressure contact with the outer surface B2 of the tube body B to cut into the outer surface B2 most deeply in the sleeve 4. This enables a reduction in the area of the sleeve 4 clamped by the clamping member 30.

As a result, compared to a configuration in which the first tapered surface 4b and second tapered surface 4c of the sleeve 4 are approximately evenly deformed by contraction of diameter as the first inclined surface 2 and the second inclined surface 3 are moved by the clamping member 30 to approach each other relatively as in the examples illustrated in Fig. 1(a), Fig. 1(b), Fig. 2, Fig. 3(a), and Fig. 3(b), Embodiment 3 enables a reduction in clamping torque applied to the sleeve 4 by the clamping member 30 for many types of tube bodies B with different structures. Thus, advantageously, even with a change in the structure of the tube body B, the tube can be easily connected, while high sealability can be maintained. Moreover, when the retaining recessed and protruding part lb is arranged on the nipple 1 opposite the inner circumference area of the second tapered surface 4c and the annular seal member 6 as in the examples illustrated in Fig. 4(a) and Fig. 4(b), a high seal effect and a high retaining effect can advantageously be achieved.

[Embodiment 4]

[0037] As shown in Fig. 5(a), Fig. 5(b), and Fig. 6, Embodiment 4 is different from Embodiment 1 shown in Fig. 1(a), Fig. 1(b), and Fig. 2, Embodiment 2 shown in Fig. 3(a) and Fig. 3(b), and Embodiment 3 shown in Fig. 4(a) and Fig. 4(b) in that the sleeve 4 includes, on the inner circumference surface thereof, a contact pressure part 4g which is smooth along the inserting space S for the tube body B and which is prevented from protruding beyond the projection part 4d and in that the contact pressure part 4g is located opposite an opening end Id of the nipple 1 when the sleeve 4 is deformed by contraction of diameter. Embodiment 4 is the same as Embodiment 1 shown in Fig. 1(a), Fig. 1(b), and Fig. 2, Embodiment 2 shown in Fig. 3(a) and Fig. 3(b), and Embodiment 3 shown in Fig. 4(a) and Fig. 4(b) in regard to the remaining part of the configuration.

[0038] In examples illustrated in Fig. 5(a), Fig. 5(b), and Fig. 6, the mounting recessed part 4e in which the seal member 6 is mounted is integrally formed in the center of the inner circumference surface of the sleeve 4 in the tube inserting direction N and the tube slip-out direction U. One projection part 4d is arranged on the tube inserting direction N side and on the tube slip-out direction U side across the mounting recessed part 4e. A smooth part 2g is integrally molded at each of the opposite ends of the inner circumference surface. Thus, the sleeve 4 as a whole is configured to be symmetric in the tube inserting direction N and the tube slip-out direction U. In the example illustrated in Fig. 6, a plurality of recessed parts 4h is formed as recesses in the tapered surface 4b and in the reverse tapered surface 4c of the sleeve 4 to reduce the area in which the first inclined surface 2 of the tubular member 20 contacts the second inclined surface 3 of the clamping member 30. Thus, the sleeve 4 as a whole is smoothly deformed by contraction of diameter as the first inclined surface 2 and the second inclined surface 3 move to approach each other relatively. Furthermore, although not shown in the drawings, in another example, the tapered surface 4b and reverse tapered surface 4c of the sleeve 4 may be formed to include no recessed part 4h but to be smooth inner circumference surfaces as shown in Embodiment 1, Embodiment 2, and Embodiment 3.

[0039] Moreover, in Embodiment 4, a flange part 10c is integrally formed on the back side of the nipple 1 in the tube inserting direction N as the joint main body 10. The flange part 10c is detachably connected to another device (not shown in the drawings) for connection to the tube joint A by being joined to a flange part (not shown in the drawings) formed in the device and having the same shape as that of the flange part 10c and installing an annular coupling member (not shown in the drawings) over the flange parts. In the illustrated examples, the flange part 10c includes an annular groove lOd formed in a connection end surface of the flange part 10c as a recess and into which an annular seal member such as an O ring (not shown in die drawings) is fitted. Furthermore, although not shown in the drawings, in another example, the flange part 10c may be formed separately from the nipple 1 as the joint main body 10 and detachably mounted on the nipple 1.

[0040] According to the tube joint A according to Embodiment 4 of the present invention, as the sleeve 4 as a whole is deformed by contraction of diameter while the first inclined surface 2 and the second inclined surface 3 are moving to approach each other relatively, the smooth contact pressure part 4g comes into surface contact with the outer surface B2 of the tube body B opposite the opening end Id of the nipple 1. Thus, even when the projection part 4d is placed near the opening end Id of the nipple 1, the inner surface Bl of the tube body B is prevented from being deformed inward of the inner circumference surface le of the nipple 1 in a swelling manner. Therefore, a fluid flowing through the tube body B and the nipple 1 can pass through smoothly without any resistance. This advantageously allows prevention of a pressure loss caused by a decrease in the fluid flowing through the tube body B and die nipple 1.

[0041] In the illustrated case in Embodiment 1, Embodiment 2, and Embodiment 3 described above, the threaded part 10a and the tool engagement part 10b are formed on the back side of the nipple 1 in the tube inserting direction N as the joint main body 10. However, the present invention is not limited to this case, and instead of the threaded part 10a and the tool engagement part 10b, the flange part 10c may be formed as the joint main body 10 as in Embodiment 4 described above. In contrast, in the illustrated case in Embodiment 4, the flange part 10c is formed on the back side of the nipple 1 in the tube inserting direction N as the joint main body 10.

However, the present invention is not limited to this case, and instead of the flange part 10c, the threaded part 10a and the tool engagement part 10b may be formed as in Embodiment 1 and the like. Moreover, in the illustrated examples, the internal thread part and the external thread part 21, engaged with each other in a threadable manner, is formed as the slide means 31 moving the clamping member 30 in the axial direction relative to the nipple 1. However, the present invention is not limited to this, a structure other than the thread may be used provided that the structure allows the clamping member 30 to move in the axial direction relative to the sleeve 4. Furthermore, in the description, a hose of a single layer structure is used as the tube body B, and alternatively, a laminated hose or a spiral reinforced hose may be used. However, the present invention is not limited to this, and a tube or the like may be used instead of the hose.

EXPLANATION OF REFERENCE NUMERALS

[0042]

1 Nipple la Outer circumference surface Id Opening end 20 Tubular member
2 First inclined surface
2a Stopper 30 Clamping member
3 Second inclined surface
4 Sleeve
4b First tapered surface 4c Second tapered surface 4d Projection part 4f Back-side end of sleeve 4g Contact pressure part
5 Annular recessed part 5a Step part
6 Seal member
6a Inner circumference end
B Tube body
Bl Inner surface
B3 Outer circumference area of tip
S Inserting space for tube body
N Inserting direction of tube body (tube inserting direction)
U Direction opposite to inserting direction of tube body (tube slip-out direction)

CLAIMS

What is claimed is:

1. A tube joint comprising: a nipple provided along an inserting space for a flexible tube body; a tubular member provided opposite an outer circumference surface of said nipple across said inserting space for said tube body in a radial direction, and having a first inclined surface formed to have an inside diameter gradually decreasing in an inserting direction of said tube body; a clamping member located opposite said outer circumference surface of said nipple across the inserting space for said tube body in die radial direction and opposite said first inclined surface in said inserting direction of said tube body, and provided to be able to make reciprocate movement in said inserting direction of said tube body relative to said first inclined surface, said clamping member having a second inclined surface formed to have an inside diameter gradually decreasing in a direction opposite to said inserting direction of said tube body; and a sleeve located opposite said outer circumference surface of said nipple across said inserting space for said tube body in the radial direction and provided between said first inclined surface and said second inclined surface so as to be able to make reciprocal movement in said inserting direction of said tube body and to be elastically deformable in the radial direction, said sleeve being formed so as to be deformed by contraction of diameter as said first inclined surface and said second inclined surface move to approach each other relatively,

wherein said first inclined surface of said tubular member includes a recessed stopper abutted by a back-side end of said sleeve in said inserting direction of said tube body when said first inclined surface and said second inclined surface move to approach each other relatively, and said back-side end of said sleeve includes a step part formed to have a thickness larger than an amount by which said stopper is recessed and protruding from an inner circumference surface of said tubular member toward said outer circumference surface of said nipple when said back-side end abuts against said stopper, and an annular recessed part is formed in said inner circumference surface of said tubular member which is located further toward the back than said step part in said inserting direction of said tube body, said annular recessed part being formed opposite said inserting space for said tube body in the radial direction so as to communicate with said inserting space, and said annular recessed part is formed to have a diameter larger than an inside diameter of said sleeve during diameter contraction and to annularly deform an outer circumference area of a tip of said tube body in a swelling manner to impact the outer circumference surface area into said annular recessed part as said sleeve is deformed by contraction of diameter.

2. The tube joint according to Claim 1, wherein an annular seal member is provided on an inner circumference surface of said sleeve so that an inner circumference end of the seal member protrudes toward said inserting space for the tube body.

3. The tube joint according to Claim 1 or Claim 2, wherein a plurality of projection parts protruding toward said inserting space for the tube body is arranged on an inner circumference surface of said sleeve at predetermined intervals in said inserting direction of said tube body.

4. The tube joint according to Claim 1, Claim 2, or Claim 3, wherein a first tapered surface opposite to said first inclined surface and a second tapered surface opposite to said second inclined surface are formed on an outer circumference surface of said sleeve so as to be shaped symmetrically in said inserting direction of said tube body and in said opposite direction.

5. The tube joint according to Claim 1, Claim 2, Claim 3, or Claim 4, wherein said sleeve includes a first tapered surface opposite to said first inclined surface and a second tapered surface opposite to said second inclined surface, and as said first inclined surface and said second inclined surface are moved by said clamping member to approach each other relatively, said second tapered surface is deformed by contraction of diameter more significantly than said first tapered surface so that said back-side end of said sleeve abuts against said stopper and is inclined along said second inclined surface, and a part of said tube body is compressively deformed and partly clamped between an inner circumference area of said second tapered surface and said outer circumference surface of said nipple.

6. The tube joint according to Claim 5, wherein an inner circumference surface of said sleeve is provided with a projection part protruding toward said inserting space for said tube body and a contact pressure part which is smooth along said inserting space for said tube body and which is prevented from protruding beyond said projection part, and said contact pressure part is arranged to oppose an opening end of said nipple when said sleeve is deformed by contraction of diameter.

7. (Deleted)