[0001]The present invention relates to a shock absorber.
This application claims priority based on Japanese Patent Application No. 2019-059207 filed in Japan on March 26, 2019, the contents of which are incorporated herein by reference.
Background technology
[0002]
　A shock absorber having two valves that open in the same stroke is disclosed (see, for example, Patent Documents 1 to 3).
Prior art literature
Patent documents
[0003]
Patent Document 1: Japanese Patent No. 5949789
Patent Document 2: Japanese Patent Application Laid-Open No. 2018-76920
Patent Document 3: Japanese Patent No. 6391512
Outline of the invention
Problems to be solved by the invention
[0004]
　There is a need for structural simplification in shock absorbers.
[0005]
　Therefore, an object of the present invention is to provide a shock absorber capable of simplifying the structure.
Means to solve problems
[0006]
　One aspect of the shock absorber of the present invention is provided in a first passage formed in a piston, and a first damping force generating mechanism for generating a damping force and a piston rod are inserted and arranged on one chamber side. The first passage has a second damping force generating mechanism provided in a second passage in parallel to generate a damping force, and the second damping force generating mechanism has a bottomed cylinder having a cylinder portion and a bottom portion. An annular first valve seat formed in the tubular portion of the case member, and an annular disc valve in which a detachable portion on the outer peripheral side is detachably arranged on the first valve seat of the case member. A second valve seat provided on the side opposite to the first valve seat of the disc valve and supporting the inside of the disc valve in the radial direction with respect to the detachable portion so as to be detachable, and the second passage. Is a chamber passage portion that communicates with a piston rod passage portion formed by notching or penetrating the piston rod and a chamber inner chamber between the piston rod passage portion and the bottom portion of the case member and the disc valve. In a region where the piston speed is low, the first damping force generation mechanism is closed and the second damping force generation mechanism is opened, and in a speed region where the piston speed is higher than the low speed. Both the first damping force generation mechanism and the second damping force generation mechanism open.
The invention's effect
[0007]
　According to the above shock absorber, it is possible to simplify the structure.
A brief description of the drawing
[0008]
FIG. 1 is a cross-sectional view showing a shock absorber according to the first embodiment of the present invention.
FIG. 2 is a partial cross-sectional view showing a main part of the shock absorber according to the first embodiment of the present invention.
FIG. 3 is a partial cross-sectional view showing the periphery of a disc valve of the shock absorber according to the first embodiment of the present invention.
FIG. 4 is a plan view showing a disc valve of the shock absorber according to the first embodiment of the present invention.
FIG. 5 is a plan view showing a modification 1 of the disc valve of the shock absorber according to the first embodiment of the present invention.
FIG. 6 is a plan view showing a modification 2 of the disc valve of the shock absorber according to the first embodiment of the present invention.
FIG. 7 is a plan view showing a modification 3 of the disc valve of the shock absorber according to the first embodiment of the present invention.
FIG. 8 is a plan view showing a modified example 4 of the disc valve of the shock absorber according to the first embodiment of the present invention.
FIG. 9 is a cross-sectional view showing a main part of the shock absorber of the second embodiment according to the present invention.
FIG. 10 is a cross-sectional view showing a main part of a shock absorber according to a third embodiment of the present invention.
FIG. 11 is a partial cross-sectional view showing the periphery of a disc valve of the shock absorber according to the third embodiment of the present invention.
FIG. 12 is a cross-sectional view showing a main part of a shock absorber according to a fourth embodiment of the present invention.
FIG. 13 is a cross-sectional view showing a main part of a shock absorber according to a fifth embodiment of the present invention.
Embodiment for carrying out the invention
[0009]
[First Embodiment] The first embodiment according to the
　present invention will be described with reference to FIGS. 1 to 8. In the following, for convenience of explanation, the upper side in FIGS. 1 to 3 and 9 to 13 will be referred to as “upper”, and the lower side in FIGS. 1 to 3 and 9 to 13 will be referred to as “lower”. ..
[0010]
　As shown in FIG. 1, the shock absorber 1 of the first embodiment is a so-called double-cylinder type hydraulic shock absorber, and includes a cylinder 2 in which an oil solution (not shown) as a working fluid is sealed. The cylinder 2 has a cylindrical inner cylinder 3 and a bottomed cylindrical outer cylinder 4 having a diameter larger than that of the inner cylinder 3 and provided concentrically so as to cover the inner cylinder 3. A reservoir chamber 6 is formed between the inner cylinder 3 and the outer cylinder 4.
[0011]
　The outer cylinder 4 includes a cylindrical body member 11 and a bottom member 12 that is fitted to the lower side of the body member 11 and fixed by welding to close the lower part of the body member 11. A mounting eye 13 is fixed to the bottom member 12 at an outer position opposite to the body member 11 by welding.
[0012]
　The shock absorber 1 includes a piston 18 slidably provided inside the inner cylinder 3 of the cylinder 2. The piston 18 defines two chambers in the inner cylinder 3, an upper chamber 19 which is an inner chamber of one cylinder and a lower chamber 20 which is an inner chamber of the other cylinder. In other words, the piston 18 is slidably provided in the cylinder 2 and divides the inside of the cylinder 2 into an upper chamber 19 on one side and a lower chamber 20 on the other side. An oil solution as a working fluid is sealed in the upper chamber 19 and the lower chamber 20 in the inner cylinder 3. An oil liquid and a gas as working fluids are sealed in the reservoir chamber 6 between the inner cylinder 3 and the outer cylinder 4.
[0013]
　The shock absorber 1 includes a piston rod 21 whose one end side portion in the axial direction is arranged inside the inner cylinder 3 of the cylinder 2 and is connected and fixed to the piston 18 and the other end side portion extends to the outside of the cylinder 2. ing. The piston rod 21 penetrates the upper chamber 19 and does not penetrate the lower chamber 20. Therefore, the upper chamber 19 is a rod side chamber through which the piston rod 21 penetrates, and the lower chamber 20 is a bottom side chamber on the bottom side of the cylinder 2.
[0014]
　The piston 18 and the piston rod 21 move integrally. The piston 18 moves toward the upper chamber 19 in the extension stroke of the shock absorber 1 in which the piston rod 21 increases the amount of protrusion from the cylinder 2. The piston 18 moves toward the lower chamber 20 in the contraction stroke of the shock absorber 1 in which the piston rod 21 reduces the amount of protrusion from the cylinder 2.
[0015]
　A rod guide 22 is fitted to the upper end opening side of the inner cylinder 3 and the outer cylinder 4, and a seal member 23 is fitted to the outer cylinder 4 on the upper side which is the outer side of the cylinder 2 with respect to the rod guide 22. ing. Both the rod guide 22 and the seal member 23 have an annular shape. The piston rod 21 is slidably inserted inside each of the rod guide 22 and the seal member 23, and extends from the inside of the cylinder 2 to the outside.
[0016]
　The rod guide 22 supports the piston rod 21 so as to be movable in the axial direction while restricting its radial movement, and guides the movement of the piston rod 21. The seal member 23 is in close contact with the outer cylinder 4 at its outer peripheral portion, and is in sliding contact with the outer peripheral portion of the piston rod 21 moving in the axial direction at its inner peripheral portion. As a result, the seal member 23 prevents the oil liquid in the inner cylinder 3 and the high-pressure gas and the oil liquid in the reservoir chamber 6 in the outer cylinder 4 from leaking to the outside.
[0017]
　The outer peripheral portion of the rod guide 22 has a stepped shape in which the upper portion has a larger diameter than the lower portion. The outer peripheral portion of the rod guide 22 is fitted to the inner peripheral portion of the upper end of the inner cylinder 3 at the lower portion of the small diameter, and is fitted to the inner peripheral portion of the upper portion of the outer cylinder 4 at the upper portion of the large diameter. A base valve 25 that defines the lower chamber 20 and the reservoir chamber 6 is installed on the bottom member 12 of the outer cylinder 4. The inner peripheral portion of the lower end of the inner cylinder 3 is fitted to the base valve 25. The upper end portion of the outer cylinder 4 is crimped inward in the radial direction to form a locking portion 26. The locking portion 26 and the rod guide 22 sandwich the seal member 23.
[0018]
　The piston rod 21 has a spindle portion 27, a mounting shaft portion 28 having a diameter smaller than that of the spindle portion 27, and a screw shaft portion 31 on the side opposite to the spindle portion 27 of the mounting shaft portion 28. The spindle portion 27 of the piston rod 21 is slidably fitted to the rod guide 22 and the seal member 23. The mounting shaft portion 28 and the screw shaft portion 31 of the piston rod 21 are arranged in the cylinder 2 and connected to the piston 18 and the like. The end portion of the spindle portion 27 on the mounting shaft portion 28 side is a shaft step portion 29 extending in the direction orthogonal to the axis.
On the outer peripheral portion of the mounting shaft portion 28, a passage notch 30 extending in the axial direction is formed at an intermediate position in the axial direction. The passage notch 30 is formed by, for example, notching the outer peripheral portion of the mounting shaft portion 28 in a plane parallel to the central axis of the mounting shaft portion 28. The passage cutout portion 30 can be formed into a so-called two-sided width shape formed by cutting out two positions of the mounting shaft portion 28, which differ by 180 degrees in the circumferential direction, in parallel in a plane. The mounting shaft portion 28 has a cylindrical surface except for the passage cutout portion 30. The screw shaft portion 31 is provided at the tip position inside the cylinder 2 on the piston rod 21. A male screw 32 is formed on the outer peripheral portion of the screw shaft portion 31.
[0019]
　In the shock absorber 1, for example, a protruding portion of the piston rod 21 from the cylinder 2 is arranged at an upper portion and supported by the vehicle body. In the shock absorber 1, the mounting eye 13 on the cylinder 2 side is arranged at the lower part and connected to the wheel side. On the contrary, the cylinder 2 side may be supported by the vehicle body and the piston rod 21 may be connected to the wheel side.
[0020]
　As shown in FIG. 2, the piston 18 is a composite of a metal piston body 35 connected to the piston rod 21 and an annular shape that is integrally mounted on the outer peripheral surface of the piston body 35 and slides in the inner cylinder 3. It is composed of a sliding member 36 made of resin.
[0021]
　The piston body 35 can communicate with a plurality of passage holes 37 capable of communicating the upper chamber 19 and the lower chamber 20 (only one place is shown in FIG. 2 due to the cross section), and the upper chamber 19 and the lower chamber 20 can communicate with each other. There are a plurality of passage holes 39 (only one is shown in FIG. 2 because of the cross section). The piston body 35 is a sintered product.
[0022]
　The plurality of passage holes 37 are formed at equal pitches with one passage hole 39 sandwiched between them in the circumferential direction of the piston body 35. The plurality of passage holes 37 constitute half of the passage holes 37 and 39. The plurality of passage holes 37 have a crank shape having two bending points. In the plurality of passage holes 37, one side in the axial direction of the piston 18 (upper side in FIG. 2) is outside in the radial direction of the piston 18, and the other side in the axial direction of the piston 18 (lower side in FIG. 2) is a piston rather than one side. It is open inward in the radial direction of 18. The piston body 35 is formed with an annular groove 55 on the lower chamber 20 side in the axial direction, which allows a plurality of passage holes 37 to communicate with each other.
[0023]
　On the lower chamber 20 side of the annular groove 55, a first damping force generation mechanism 41 for opening and closing the passages in the annular groove 55 and the plurality of passage holes 37 to generate a damping force is provided. By arranging the first damping force generation mechanism 41 on the lower chamber 20 side, the passages in the plurality of passage holes 37 and the annular groove 55 move to the upper chamber 19 side of the piston 18, that is, upstream in the extension stroke. It is a passage on the extension side where the oil liquid flows from the upper chamber 19 on the side to the lower chamber 20 on the downstream side. The first damping force generating mechanism 41 provided for the passages in the plurality of passage holes 37 and the annular groove 55 is from the passages in the plurality of passage holes 37 on the extension side and the passages in the annular groove 55 to the lower chamber 20. It is a damping force generation mechanism on the extension side that suppresses the flow of oil and liquid and generates damping force.
[0024]
　The passage holes 39 constituting the other half of the passage holes 37 and 39 are formed at equal pitches with one passage hole 37 sandwiched between them in the circumferential direction of the piston main body 35.
The plurality of passage holes 39 have a crank shape having two bending points. In the plurality of passage holes 39, the other side in the axial direction of the piston 18 (lower side in FIG. 2) is outside in the radial direction of the piston 18, and one side in the axial direction of the piston 18 (upper side in FIG. 2) is the piston than the other side. It is open inward in the radial direction of 18. The piston body 35 is formed with an annular groove 56 that allows a plurality of passage holes 39 to communicate with each other on the upper chamber 19 side in the axial direction.
[0025]
　On the upper chamber 19 side of the annular groove 56, a first damping force generation mechanism 42 for opening and closing the passages in the plurality of passage holes 39 and the annular groove 56 to generate a damping force is provided. By arranging the first damping force generation mechanism 42 on the upper chamber 19 side, the passages in the plurality of passage holes 39 and the annular groove 56 move to the lower chamber 20 side of the piston 18, that is, upstream in the contraction stroke. It is a passage on the contraction side where the oil liquid flows from the lower chamber 20 on the side to the upper chamber 19 on the downstream side. The first damping force generating mechanism 42 provided for the passages in the plurality of passage holes 39 and the annular groove 56 is from the passages in the plurality of passage holes 39 on the contraction side and the passages in the annular groove 56 to the upper chamber 19. It is a damping force generation mechanism on the contraction side that suppresses the flow of oil and liquid and generates damping force.
[0026]
　The piston body 35 has a substantially disk shape. At the center of the piston body 35 in the radial direction, an insertion hole 44 into which the mounting shaft portion 28 of the piston rod 21 is inserted is formed so as to penetrate in the axial direction. The insertion hole 44 has a small diameter hole portion 45 on one side in the axial direction for fitting the mounting shaft portion 28 of the piston rod 21, and a large diameter hole portion 46 on the other side in the axial direction having a larger diameter than the small diameter hole portion 45. is doing.
[0027]
　At the end of the piston body 35 on the lower chamber 20 side in the axial direction, an annular inner seat portion 47 is formed inside the piston body 35 in the radial direction from the opening on the lower chamber 20 side of the annular groove 55. There is. At the end of the piston body 35 on the lower chamber 20 side in the axial direction, a part of the first damping force generating mechanism 41 is located outside the piston body 35 in the radial direction from the opening on the lower chamber 20 side of the annular groove 55. The annular valve seat portion 48 constituting the above is formed.
[0028]
　At the end of the piston body 35 on the upper chamber 19 side in the axial direction, an annular inner sheet portion 49 is formed inside the piston body 35 in the radial direction from the opening on the upper chamber 19 side of the annular groove 56. .. At the end of the piston body 35 on the upper chamber 19 side in the axial direction, a part of the first damping force generating mechanism 42 is located outside the piston body 35 in the radial direction from the opening on the upper chamber 19 side of the annular groove 56. The annular valve seat portion 50 constituting the above is formed.
[0029]
　The insertion hole 44 of the piston body 35 is provided with a large-diameter hole portion 46 on the inner sheet portion 47 side in the axial direction with respect to the small-diameter hole portion 45. The passage in the large-diameter hole portion 46 of the piston body 35 overlaps the position in the axial direction with the piston rod passage portion 51 in the passage notch 30 of the piston rod 21 and is always communicated with the passage.
[0030]
　In the piston body 35, the radial outer side of the valve seat portion 48 has a stepped shape having a lower axial height than the valve seat portion 48. An opening on the lower chamber 20 side of the passage hole 39 on the contraction side is arranged in this stepped portion. Similarly, in the piston main body 35, the radial outer side of the valve seat portion 50 has a stepped shape having a lower axial height than the valve seat portion 50. An opening on the upper chamber 19 side of the passage hole 37 on the extension side is arranged in this stepped portion.
[0031]
　The first damping force generation mechanism 42 on the contraction side includes the valve seat portion 50 of the piston 18. The first damping force generating mechanism 42 on the contraction side includes one disk 62, and a plurality of (specifically four) disks 63 having the same inner diameter and the same outer diameter, in order from the piston 18 side in the axial direction. It has a plurality of discs (specifically, two discs) having the same inner diameter and the same outer diameter. At a position of the disc 64 opposite to the disc 63, one disc 65, one disc 66, and one annular member 67 are provided in this order from the disc 64 side. The annular member 67 is in contact with the shaft step portion 29 of the piston rod 21. The discs 62 to 66 and the annular member 67 are made of metal. The discs 62 to 66 and the annular member 67 each have a perforated circular flat plate shape having a constant thickness to which the mounting shaft portion 28 of the piston rod 21 can be fitted.
[0032]
　The disk 62 has an outer diameter larger than the outer diameter of the inner seat portion 49 of the piston 18 and smaller than the inner diameter of the valve seat portion 50. The disk 62 is always in contact with the inner sheet portion 49. The plurality of discs 63 have an outer diameter substantially equal to the outer diameter of the valve seat portion 50 of the piston 18. The plurality of discs 63 can be seated on the valve seat portion 50.
[0033]
　The plurality of discs 64 have an outer diameter smaller than the outer diameter of the disc 63. The disc 65 has an outer diameter smaller than the outer diameter of the disc 64 and a smaller diameter than the outer diameter of the inner seat portion 49 of the piston 18. The disc 66 has an outer diameter larger than the outer diameter of the disc 64 and a smaller diameter than the outer diameter of the disc 63. The annular member 67 has an outer diameter smaller than the outer diameter of the disc 66 and a larger diameter than the outer diameter of the shaft step portion 29 of the piston rod 21. The annular member 67 is thicker and more rigid than the discs 62 to 66.
[0034]
　A plurality of discs 63 and a plurality of discs 64 made of a thin metal plate constitute a contraction-side main valve 71 that is flexible and can be taken off and seated on the valve seat portion 50. By separating the main valve 71 from the valve seat portion 50, the passages in the annular groove 56 and the plurality of passage holes 39 are communicated with the upper chamber 19, and the oil liquid flows between the main valve 71 and the valve seat portion 50. Suppresses and generates damping force. The annular member 67, together with the disc 66, regulates the deformation of the main valve 71 in the opening direction beyond the specified value.
[0035]
　The passage between the main valve 71 and the valve seat portion 50 that appears at the time of valve opening and the passage in the annular groove 56 and in the plurality of passage holes 39 move into the cylinder 2 due to the movement of the piston 18 toward the lower chamber 20 side. The first passage 72 on the contraction side through which the oil liquid flows from the lower chamber 20 on the upstream side to the upper chamber 19 on the downstream side is configured. Therefore, the first passage 72 is formed in the piston 18.
[0036]
　The first damping force generation mechanism 42 on the contraction side that generates damping force includes a main valve 71 and a valve seat portion 50. Therefore, the first damping force generation mechanism 42 on the contraction side is provided in the first passage 72. The first passage 72 is provided in the piston 18 including the valve seat portion 50, and the oil liquid passes through when the piston rod 21 and the piston 18 move to the contraction side.
[0037]
　The first damping force generating mechanism 42 on the contraction side allows both the valve seat portion 50 and the main valve 71 in contact with the valve seat portion 50 to communicate the upper chamber 19 and the lower chamber 20 even when they are in contact with each other. No fixed orifice is formed. That is, the first damping force generation mechanism 42 on the contraction side does not allow the upper chamber 19 and the lower chamber 20 to communicate with each other if the valve seat portion 50 and the main valve 71 are in contact with each other over the entire circumference. In other words, the first passage 72 is not formed with a fixed orifice that always communicates the upper chamber 19 and the lower chamber 20, and is not a passage that always communicates the upper chamber 19 and the lower chamber 20.
[0038]
　The extension-side first damping force generation mechanism 41 includes a valve seat portion 48 of the piston 18. The first damping force generation mechanism 41 on the extension side includes one disk 82 and a plurality of (specifically five) disks 83 having the same inner diameter and the same outer diameter in order from the piston 18 side in the axial direction. Have. On the opposite side of the disc 83 from the disc 82, a plurality of (specifically, two) discs 84 having the same inner diameter and the same outer diameter are provided. The discs 82 to 84 are made of metal and each have a perforated circular flat plate shape having a constant thickness to which the mounting shaft portion 28 of the piston rod 21 can be fitted.
[0039]
　The disk 82 has an outer diameter larger than the outer diameter of the inner seat portion 47 of the piston 18 and smaller than the inner diameter of the valve seat portion 48. The disk 82 is always in contact with the inner sheet portion 47. As shown in FIG. 3, the disk 82 is formed with a notch 88 from an intermediate position outside the inner sheet portion 47 in the radial direction to an inner peripheral edge portion. The notch 88 constantly communicates the passage in the annular groove 55 and the plurality of passage holes 37 to the passage in the large diameter hole 46 of the piston 18 and the piston rod passage 51 in the passage notch 30 of the piston rod 21. Let me. The notch 88 is formed during press molding of the disc 82.
[0040]
　As shown in FIG. 2, the plurality of discs 83 have an outer diameter substantially equal to the outer diameter of the valve seat portion 48 of the piston 18. The plurality of discs 83 can be seated on the valve seat portion 48. The disk 84 has an outer diameter smaller than the outer diameter of the disk 83 and smaller than the outer diameter of the inner seat portion 47 of the piston 18.
[0041]
　A plurality of discs 83 made of a thin metal plate constitute a main valve 91 on the extension side that is flexible and can be taken off and seated on the valve seat portion 48. By separating the main valve 91 from the valve seat portion 48, the passages in the annular groove 55 and the plurality of passage holes 37 are communicated with the lower chamber 20, and the flow of oil and liquid between the main valve 91 and the valve seat portion 48. Suppresses and generates damping force.
[0042]
　The passage between the main valve 91 and the valve seat portion 48 that appears at the time of valve opening and the passage in the annular groove 55 and in the plurality of passage holes 37 move into the cylinder 2 due to the movement of the piston 18 toward the upper chamber 19. The first passage 92 on the extension side through which the oil liquid flows out from the upper chamber 19 on the upstream side to the lower chamber 20 on the downstream side is configured. Therefore, the first passage 92 is formed in the piston 18.
[0043]
　The extension-side first damping force generation mechanism 41 that generates a damping force includes a main valve 91 and a valve seat portion 48. Therefore, the extension-side first damping force generation mechanism 41 is provided in the first passage 92. The first passage 92 is provided in the piston 18 including the valve seat portion 48, and the oil liquid passes through when the piston rod 21 and the piston 18 move to the extension side.
[0044]
　A fixed orifice that communicates the upper chamber 19 and the lower chamber 20 even when they are in contact with each of the valve seat portion 48 and the main valve 91 that abuts on the valve seat portion 48 has a first damping force generation mechanism on the extension side. It is not formed in 41. That is, the first damping force generating mechanism 41 on the extension side does not allow the upper chamber 19 and the lower chamber 20 to communicate with each other if the valve seat portion 48 and the main valve 91 are in contact with each other over the entire circumference. In other words, the first passage 92 is not formed with a fixed orifice that always communicates the upper chamber 19 and the lower chamber 20, and is not a passage that always communicates the upper chamber 19 and the lower chamber 20.
[0045]
　On the side opposite to the piston 18 of the main valve 91 on the extension side, in order from the main valve 91 side, the above-mentioned plurality of discs 84, one disc 101, one disc 102, and one disc The 103, one disc 104, one disc valve 105, a plurality of discs 106 (specifically, two discs) having the same inner diameter and the same outer diameter, and one case member 107 form a piston rod. The mounting shaft portion 28 of 21 is provided so as to be fitted inside each of them.
[0046]
　A screw shaft portion 31 is formed on the piston rod 21 at a portion of the mounting shaft portion 28 opposite to the main shaft portion 27 and protruding from the case member 107 to the side opposite to the piston 18. A nut 108 is screwed into the male screw 32 of the screw shaft portion 31. The nut 108 is in contact with the case member 107. The screw shaft portion 31 has a male screw 32 which is a complete screw portion screwed to the nut 108, and an incomplete screw portion 109 at the end portion on the mounting shaft portion 28 side. The case member 107 covers the incompletely threaded portion 109.
[0047]
　The discs 101 to 104, the disc valve 105, the disc 106, and the case member 107 are all made of metal. The discs 101 to 104, the disc valve 105, and the disc 106 all have a perforated circular flat plate shape having a constant thickness to which the mounting shaft portion 28 of the piston rod 21 can be fitted inside. The case member 107 has an annular shape inside which the mounting shaft portion 28 of the piston rod 21 can be fitted.
[0048]
　The case member 107 is a bottomed tubular integrally molded product. The case member 107 includes a perforated disk-shaped bottom portion 111, an annular outer tubular portion 112 (cylindrical portion) projecting from the outer peripheral edge portion of the bottom portion 111 to one side in the axial direction of the bottom portion 111, and an inner portion of the bottom portion 111. It has an annular inner cylinder portion 113 protruding from the peripheral portion to the same side as the outer cylinder portion 112. The outer cylinder portion 112 and the inner cylinder portion 113 are arranged coaxially. The outer tubular portion 112 has a longer axial length than the inner tubular portion 113. The case member 107 is arranged so that the bottom portion 111 is located on the side opposite to the piston 18 with respect to the outer cylinder portion 112 and the inner cylinder portion 113. The case member 107 fits into the mounting shaft portion 28 at the inner peripheral portion of the bottom portion 111 and covers the incompletely threaded portion 109.
[0049]
　The outer tubular portion 112 forms a continuous annular shape over the entire circumference. The inner peripheral surface of the outer tubular portion 112 is a tapered surface whose diameter increases as the distance from the bottom portion 111 in the axial direction increases. The outer peripheral surface of the outer tubular portion 112 constitutes the same cylindrical surface as the outer peripheral surface of the bottom portion 111. The tip surface of the outer cylinder portion 112 on the side opposite to the bottom portion 111 in the axial direction is a plane orthogonal to the central axis of the case member 107.
[0050]
　The angular edge portion on the boundary side between the distal end surface and the inner peripheral surface of the outer tubular portion 112 forms an annular shape. It is the first valve seat 115 on which the disc valve 105 takes off and sits. Therefore, the first valve seat 115 is formed in an annular shape on the outer tubular portion 112 of the case member 107.
[0051]
　The inner cylinder portion 113 has a tapered surface whose outer peripheral surface becomes smaller in diameter as the outer peripheral surface is separated from the bottom portion 111 in the axial direction. The tip surface opposite to the bottom 111 in the axial direction is a plane orthogonal to the central axis of the case member 107. A plurality of passage grooves 121 that open in the tip surface and penetrate in the radial direction are formed in the inner cylinder portion 113 at intervals in the circumferential direction. Therefore, the inner cylinder portion 113 is not formed continuously over the entire circumference, but is formed intermittently in the circumferential direction.
[0052]
　The case member 107 has an insertion hole 125 formed in the center in the radial direction thereof so as to penetrate the bottom portion 111 and the inner cylinder portion 113 in the axial direction and to insert the mounting shaft portion 28 and the screw shaft portion 31 of the piston rod 21. ing. The insertion hole 125 has a small diameter hole portion 126 on one side in the axial direction that fits the mounting shaft portion 28 of the piston rod 21 and covers the incomplete screw portion 109 of the screw shaft portion 31, and has a larger diameter than the small diameter hole portion 126. It has a large-diameter hole portion 127 on the other side in the axial direction. The large-diameter hole portion 127 is formed through the inner cylinder portion 113 to the inner cylinder portion 113 in the axial direction of the bottom portion 111, and the small-diameter hole portion 126 is formed with the inner cylinder portion 113 in the axial direction of the bottom portion 111. It is formed on the opposite side. Therefore, a plurality of passage grooves 121 are all open on the inner peripheral surface of the large-diameter hole portion 127.
[0053]
　The passage in the large-diameter hole portion 127 is always communicated with the piston rod passage portion 51 in the passage notch 30 of the piston rod 21 so as to overlap the axial position. The chamber passage portion 131 in the passage groove 121 of the inner cylinder portion 113 always communicates with the passage in the large diameter hole portion 127.
[0054]
　The incomplete threaded portion 109 is arranged within the axial range of the bottom portion 111 of the case member 107. Within the axial range of the bottom 111 of the case member 107, the mounting shaft portions 28 and the male screw 32 on both sides of the bottom 111 of the case member 107 in the axial direction are arranged. The case member 107 is positioned in the radial direction with the bottom portion 111 fitted to the mounting shaft portion 28 in the small diameter hole portion 126.
[0055]
　The disc 101 has an outer diameter larger than the outer diameter of the disc 84, and is thicker than the disc 84. The disc 102 has an outer diameter larger than the outer diameter of the disc 101, and is thinner than the disc 101. The disc 103 has an outer diameter larger than the outer diameter of the disc 102, and is thinner than the disc 101 and thicker than the disc 102. The disc 104 has an outer diameter larger than the outer diameter of the disc 103, and is thinner than the disc 103. Therefore, the outer diameters of the discs 101 to 104 become larger as they are closer to the bottom 111 of the case member 107 in the axial direction.
[0056]
　The outer diameter of the disk 104 is smaller than the inner diameter of the tip end surface of the outer cylinder portion 112 of the case member 107, in other words, the inner diameter of the first valve seat 115. The end surface of the disk 104 on the bottom 111 side is closer to the bottom 111 in the axial direction than the tip surface of the outer cylinder 112 of the case member 107, in other words, the end surface of the first valve seat 115 opposite to the bottom 111. Have been placed.
[0057]
　The disc valve 105 is detached and seated on the outer peripheral portion of the annular shape of the disc 104 on the case member 107 side in the axial direction. The disc 104, together with the discs 101 to 103 laminated on the disc 104, constitutes a second valve seat 135 on which the disc valve 105 is taken off and seated. In other words, the second valve seat 135 supports the disc valve 105 when seated. The second valve seat 135 composed of the disks 101 to 104 has the piston rod 21 inserted inward in the radial direction.
[0058]
　The second valve seat 135 is arranged radially inward with respect to the first valve seat 115 of the case member 107, and is located on the bottom 111 side in the axial direction. The outer diameter of the disks 101 to 104 becomes smaller as the distance from the case member 107 in the axial direction increases. Since the discs 101 to 104 are made of a thin metal plate, the second valve seat 135 made of the discs 101 to 104 has a flexible configuration. On the other hand, the first valve seat 115 of the case member 107 has higher rigidity than the second valve seat 135 and basically does not bend. The support rigidity of the disc valve 105 can be adjusted by changing the thickness and outer diameter of each of the discs 101 to 104, the number of the second valve seat 135, and the like.
[0059]
　The disc 106 has an outer diameter smaller than the outer diameter of the disc 104. The disc 106 has an outer diameter equivalent to the outer diameter of the disc 84. The outer diameter of the disk 106 is the same as the outer diameter of the tip surface on the side opposite to the bottom 111 of the inner cylinder portion 113 of the case member 107.
[0060]
　The disc valve 105 is made of a thin metal plate and is flexible. The disc valve 105 has a flat plate shape as a whole in a natural state before being incorporated into the shock absorber 1. As shown in FIG. 4, the disc valve 105 in the natural state has a perforated circular flat plate-shaped outer annular portion 141 and an outer diameter smaller than the inner diameter of the outer annular portion 141, and has a diameter of the outer annular portion 141. It has a perforated circular flat plate-shaped inner annular portion 142 arranged inside in the direction, and a plurality of, specifically, two support portions 143 connecting the outer annular portion 141 and the inner annular portion 142. There is a space between the outer annular portion 141 and the inner annular portion 142 except for the two support portions 143. The disc valve 105 has a mirror-symmetrical shape.
[0061]
　The outer peripheral surface and the inner peripheral surface of the outer annular portion 141 are both circular and concentrically arranged, in other words, the outer annular portion 141 has an annular shape having a constant radial width. The inner peripheral surface and the inner peripheral surface of the inner annular portion 142 are both circular and concentrically arranged, in other words, they form an annular shape having a constant radial width. The two support portions 143 are arranged between the inner annular portion 142 and the outer annular portion 141. The two support portions 143 support the outer annular portion 141 concentrically with the inner annular portion 142.
[0062]
　As shown in FIG. 3, the inner annular portion 142 is inserted with the mounting shaft portion 28 of the piston rod 21 inside. The inner diameter of the inner annular portion 142 is such that the mounting shaft portion 28 of the piston rod 21 can be fitted, and the outer diameter is smaller than the outer diameter of the disk 104, that is, the outer diameter of the second valve seat 135. The outer diameter of the inner annular portion 142 is the same as the outer diameter of the tip surface of the inner tubular portion 113 of the case member 107 and the outer diameter of the disk 106. Therefore, in the disc valve 105, the inner annular portion 142 is clamped in the axial direction by the disc 84 and the disc 106 together with the discs 101 to 104.
[0063]
　The inner diameter of the outer annular portion 141 is smaller than the outer diameter of the disc 104, that is, the outer diameter of the second valve seat 135. The outer diameter of the outer annular portion 141 is larger than the inner diameter of the tip surface of the outer tubular portion 112 of the case member 107, that is, the diameter of the first valve seat 115. The outer diameter of the outer annular portion 141, that is, the outer diameter of the disc valve 105 is larger than the outer diameter of the main valve 91.
[0064]
　The outer annular portion 141 is capable of detaching from the first valve seat 115 of the case member 107 with the outer peripheral side separating portion 151 (disconnecting portion) on the outer peripheral side. When the outer peripheral side detaching portion 151 sits on the first valve seat 115 over the entire circumference of the outer annular portion 141, the gap between the outer annular portion 141 and the first valve seat 115 is closed. When the outer annular portion 141 is seated away from the first valve seat 115, the gap between the outer annular portion 141 and the first valve seat 115 is opened.
[0065]
　In the outer annular portion 141, the inner peripheral side separating portion 152 on the inner peripheral side can be detached from the second valve seat 135 of the disk 104. When the inner peripheral side contacting portion 152 sits on the second valve seat 135 over the entire circumference of the outer annular portion 141, the outer annular portion 141 closes the gap with the second valve seat 135. When the outer annular portion 141 is separated from the second valve seat 135, the gap between the outer annular portion 141 and the second valve seat 135 is opened. When the outer annular portion 141 is seated on the second valve seat 135, the disc 104 closes the gap between the outer annular portion 141 and the inner annular portion 142 of the disc valve 105.
[0066]
　Therefore, in the disc valve 105, the outer peripheral side separating portion 151 on the outer peripheral side is arranged so as to be detachable from the first valve seat 115 of the case member 107. The second valve seat 135 is provided on the side opposite to the first valve seat 115 in the axial direction of the disc valve 105, and the inner peripheral side contact portion 152 radially inside the outer peripheral side disconnection portion 151 of the disc valve 105. Is supported so that it can be detached.
[0067]
　As shown in FIG. 4, the two support portions 143 have two outer connecting portions 161, two inner connecting portions 162, and two connecting arm portions 163.
[0068]
　The two outer connecting portions 161 are arranged on the same side of the center in the radial direction of the disc valve 105 at intervals in the circumferential direction of the disc valve 105, and are connected to the outer annular portion 141. .. Both of the two outer connecting portions 161 project radially inward from the inner peripheral edge portion of the outer annular portion 141 to the outer annular portion 141.
[0069]
　The two inner connecting portions 162 are spaced apart from the center in the radial direction of the disc valve 105, that is, on the opposite side of the two outer connecting portions 161 in the circumferential direction of the disc valve 105. Is arranged and connected to the inner annular portion 142. Both of the two inner connecting portions 162 project from the outer peripheral edge portion of the inner annular portion 142 to the radial outer side of the inner annular portion 142.
[0070]
　The distance between the two inner connecting portions 162 is wider than the distance between the two outer connecting portions 161. The straight line connecting the two inner connecting portions 162 and the straight line connecting the two outer connecting portions 161 are parallel to each other. Therefore, the straight line connecting the midpoint of the straight line connecting the two inner connecting portions 162 and the midpoint of the straight line connecting the two outer connecting portions 161 is the center of the inner annular portion 142 and the outer annular portion 141. That is, it passes through the center of the disc valve 105. On the one hand, the distance between the outer connection portion 161 and the inner connection portion 162 that are close in the circumferential direction of the disc valve 105 is equal to the distance between the outer connection portion 161 and the inner connection portion 162 that are close in the circumferential direction of the disc valve 105. ing. This distance is longer than the distance connecting the two inner connecting portions 162 and longer than the distance connecting the two outer connecting portions 161.
[0071]
　The two connecting arm portions 163 are provided so as to connect the outer connecting portion 161 and the inner connecting portion 162, each of which is close to the circumferential direction of the disc valve 105. That is, one connecting arm portion 163 connects one outer connecting portion 161 and one inner connecting portion 162, which are close to each other in the circumferential direction of the disc valve 105. The outer connection portion 161 and the inner connection portion 162 constitute one support portion 143. The other connecting arm portion 163 connects the other outer connecting portion 161 and the other inner connecting portion 162, which are close to each other in the circumferential direction of the disc valve 105. The outer connection portion 161 and the inner connection portion 162 form the other support portion 143.
[0072]
　The two connecting arm portions 163 extend in an arc shape along the inner peripheral surface of the outer annular portion 141 and the outer peripheral surface of the inner annular portion 142, and are concentric with the outer annular portion 141 and the inner annular portion 142. It is placed on top. The two connecting arm portions 163 have the same radial distance from the inner peripheral surface of the outer annular portion 141 and the radial distance from the outer peripheral surface of the inner annular portion 142.
[0073]
　As shown in FIG. 3, when the outer annular portion 141 of the disc valve 105 is seated on the second valve seat 135 at the inner peripheral side detaching portion 152 on the inner peripheral side, the disc 104 constituting the second valve seat 135 becomes It shuts off between the outer annular portion 141 and the inner annular portion 142 of the disc valve 105. In other words, the second valve seat 135 is provided so as to be able to cut off between the outer annular portion 141 and the inner annular portion 142 of the disc valve 105.
[0074]
　The disc valve 105, the plurality of discs 106, and the case member 107 form a case inner chamber 165 inside them. In the case member 107, a predetermined range on the side opposite to the outer cylinder portion 112 and the inner cylinder portion 113 in the axial direction of the bottom portion 111 covers the incompletely threaded portion 109 of the piston rod 21. In the case member 107, this range is the washer portion 166. In the case member 107, the outer cylinder portion 112, the inner cylinder portion 113, and the predetermined range on the outer cylinder portion 112 and the inner cylinder portion 113 side in the axial direction of the bottom portion 111 form the chamber passage portion 131 and the case inner chamber 165. It is a case part 167. In other words, the case member 107 is integrally molded including the case portion 167 forming the chamber passage portion 131 and the case inner chamber 165, and the washer portion 166 covering the incompletely threaded portion 109 of the piston rod 21.
[0075]
　The incomplete threaded portion 109 is arranged within the axial range of the washer portion 166. Within the axial range of the washer portion 166, the mounting shaft portions 28 and the male screw 32 on both sides of the washer portion 166 in the axial direction are arranged. The case member 107 is positioned in the radial direction with the washer portion 166 fitted to the mounting shaft portion 28. By covering the incompletely threaded portion 109 with the washer portion 166, the disc 106 or the like can be properly fitted by completely superimposing the mounting shaft portion 28 and the axial position. The nut 108 can be properly screwed by completely superimposing the axial position on the male screw 32 which is a completely threaded portion. The washer portion 166 also serves to stabilize and balance the fastening axial force of the nut 108.
[0076]
　The case inner chamber 165 is constantly communicated with the passage in the large-diameter hole portion 127 and the piston rod passage portion 51 in the passage notch 30 via the chamber passage portion 131 in the passage groove 121 of the inner cylinder portion 113. .. In other words, the chamber passage portion 131 communicates from the piston rod passage portion 51 to the case inner chamber 165 between the bottom portion 111 and the disc valve 105. Therefore, the case inner chamber 165 includes a chamber passage portion 131 in the passage groove 121, a passage in the large-diameter hole portion 127 of the case member 107, and a piston rod passage portion 51 in the passage cutout portion 30 of the piston rod 21. As shown in FIG. 2, the passage in the large-diameter hole portion 46 of the piston 18, the passage in the notch 88 of the disk 82, and the passage in the annular groove 55 of the piston 18 and in the plurality of passage holes 37. It is always connected to the upper room 19.
[0077]
　The inner peripheral side including the inner peripheral side separating portion 152 of the outer annular portion 141 of the disc valve 105 constitutes a sub-valve 171 that can be detached and seated on the second valve seat 135. The sub valve 171 is provided on the lower chamber 20 side of the upper chamber 19 and the lower chamber 20. The sub valve 171 is provided on the case inner chamber 165 side of the lower chamber 20 and the case inner chamber 165.
[0078]
　By separating the sub valve 171 from the second valve seat 135, the lower chamber 20 passes through the gap between the second valve seat 135 and the passage between the outer annular portion 141 and the inner annular portion 142 of the disc valve 105. And the case inner chamber 165 are communicated with each other. Therefore, the sub valve 171 communicates the lower chamber 20 with the upper chamber 19. At this time, the sub-valve 171 suppresses the flow of the oil liquid between the sub-valve 171 and the second valve seat 135 to generate a damping force. The sub-valve 171 is an inflow valve that opens when oil liquid flows into the case inner chamber 165 from the lower chamber 20 through a gap with the second valve seat 135. The sub-valve 171 is a check valve that regulates the outflow of oil liquid from the case inner chamber 165 to the lower chamber 20 through the gap with the second valve seat 135.
[0079]
　The passage between the sub-valve 171 and the second valve seat 135 that appears at the time of valve opening, the passage between the outer annular portion 141 and the inner annular portion 142 of the disc valve 105, the case inner chamber 165, and the passage groove of the case member 107. The passage in the chamber passage portion 131 and the large-diameter hole portion 127 in 121, the piston rod passage portion 51 in the passage notch 30 of the piston rod 21, the passage in the large-diameter hole portion 46 of the piston 18, and the disk 82. The passage in the notch 88 and the passage in the annular groove 55 and in the plurality of passage holes 37 are on the downstream side from the lower chamber 20 which becomes the upstream side in the cylinder 2 due to the movement of the piston 18 to the lower chamber 20 side. A second passage 172 through which the oil liquid flows out is configured in the upper chamber 19. The second passage 172 is a passage on the contraction side where the oil liquid flows from the lower chamber 20 on the upstream side to the upper chamber 19 on the downstream side in the movement toward the lower chamber 20 side of the piston 18, that is, in the contraction stroke.
[0080] [0080]
　The second passage 172 includes the piston rod passage portion 51 in the passage notch 30 formed by cutting the piston rod 21. In other words, a part of the second passage 172 is formed by cutting out the piston rod 21. In addition to forming the piston rod 21 by cutting out, one end is opened in the passage in the large-diameter hole portion 127 of the case member 107, and the other end is opened in the passage in the large-diameter hole portion 46 of the piston 18. The piston rod passage portion 51 may be formed by penetrating the inside of the piston rod 21 in a hole shape. Therefore, the second passage 172 is a case between the piston rod passage portion 51 formed by notching or penetrating the piston rod 21 and the bottom portion 111 of the case member 107 from the piston rod passage portion 51 and the disc valve 105. It has a chamber passage portion 131 that communicates with the inner chamber 165.
[0081]
　The sub-valve 171 and the second valve seat 135 are provided in the second passage 172 on the contraction side. The second passage 172 is opened and closed to form a contraction-side second damping force generation mechanism 173 that suppresses the flow of oil liquid from the second passage 172 to the upper chamber 19 to generate a damping force. The sub-valve 171 constituting the second damping force generation mechanism 173 on the contraction side is a sub-valve on the contraction side. The second damping force generation mechanism 173 including the sub-valve 171 and the second valve seat 135 allows the piston rod 21 to be inserted inward in the radial direction. The second damping force generation mechanism 173 is arranged on the lower chamber 20 side of one of the two upper chambers 19 and the lower chamber 20.
[0082]
　In the second passage 172, when the second damping force generation mechanism 173 is in the open state, the passage in the notch 88 of the disk 82 shown in FIG. 3 has the narrowest passage cross-sectional area among the fixed portions. It is squeezed more than before and after. As a result, the passage in the notch 88 of the disk 82 becomes the orifice 175 in the second passage 172. The orifice 175 is arranged on the downstream side of the sub valve 171 of the oil liquid flow when the sub valve 171 is opened and the oil liquid flows in the second passage 172. In other words, as shown in FIG. 2, the orifice 175 is arranged on the upper chamber 19 side of the sub valve 171 in the second passage 172.
[0083]
　The second damping force generation mechanism 173 on the contraction side is fixed to both the second valve seat 135 and the sub-valve 171 in contact with the second valve seat 135 so as to communicate the upper chamber 19 and the lower chamber 20 even when they are in contact with each other. No orifice is formed. That is, the second damping force generation mechanism 173 on the contraction side does not allow the upper chamber 19 and the lower chamber 20 to communicate with each other if the second valve seat 135 and the sub valve 171 are in contact with each other over the entire circumference. In other words, the second passage 172 does not form a fixed orifice that always communicates the upper chamber 19 and the lower chamber 20, and is not a passage that always communicates the upper chamber 19 and the lower chamber 20.
[0084]
　The contraction-side second passage 172 that can communicate the upper chamber 19 and the lower chamber 20 is parallel to the first passage 72 that is the contraction-side passage that also allows the upper chamber 19 and the lower chamber 20 to communicate with each other. A first damping force generation mechanism 42 is provided in the first passage 72, and a second damping force generation mechanism 173 is provided in the second passage 172. Therefore, the first damping force generation mechanism 42 and the second damping force generation mechanism 173 on the contraction side are arranged in parallel.
[0085]
　The outer peripheral side including the outer peripheral side separating portion 151 of the outer annular portion 141 of the disc valve 105 constitutes a sub-valve 181 that can be detached and seated on the first valve seat 115. The sub valve 181 is provided on the lower chamber 20 side of the upper chamber 19 and the lower chamber 20. The sub valve 181 is provided on the lower chamber 20 side of the lower chamber 20 and the case inner chamber 165.
[0086]
　The sub-valve 181 makes the upper chamber 19 into the lower chamber 20 by allowing the case inner chamber 165 and the lower chamber 20 to communicate with each other through a gap between the sub-valve 181 and the first valve seat 115. Communicate. At this time, the sub-valve 181 suppresses the flow of the oil liquid between the sub-valve 181 and the first valve seat 115 to generate a damping force. The sub-valve 181 is a discharge valve that opens when the oil liquid is discharged from the inside of the case inner chamber 165 to the lower chamber 20 through the gap with the first valve seat 115. The sub-valve 181 is a check valve that regulates the inflow of oil liquid from the lower chamber 20 into the case inner chamber 165 through a gap between the first valve seat 115 and the lower chamber 20.
[0087]
　The passage in the plurality of passage holes 37 of the piston 18, the passage in the annular groove 55, the passage in the notch 88 of the disk 82, the passage in the large diameter hole 46 of the piston 18, and the passage notch 30 of the piston rod 21. The piston rod passage portion 51 inside, the passage inside the large-diameter hole portion 127 of the case member 107, the chamber passage portion 131 in the passage groove 121, the case inner chamber 165, and the sub-valve 181 and the first valve that appear when the valve is opened. The passage between the seats 115 constitutes a second passage 182 in which the oil liquid flows out from the upper chamber 19 on the upstream side in the cylinder 2 to the lower chamber 20 on the downstream side due to the movement of the piston 18 to the upper chamber 19 side. is doing. The second passage 182 is a passage on the extension side in which the oil liquid flows from the upper chamber 19 on the upstream side to the lower chamber 20 on the downstream side in the movement toward the upper chamber 19 side of the piston 18, that is, in the extension stroke.
[0088]
　The second passage 182 includes the piston rod passage portion 51 in the passage notch 30 formed by cutting the piston rod 21. In other words, a part thereof is formed by cutting out the piston rod 21. In addition to forming the piston rod 21 by cutting it out, the piston rod passage portion 51 may be formed by penetrating the inside of the piston rod 21 in a hole shape as described above. Therefore, the second passage 182 is a case between the piston rod passage portion 51 formed by notching or penetrating the piston rod 21 and the bottom portion 111 of the case member 107 from the piston rod passage portion 51 and the disc valve 105. It has a chamber passage portion 131 that communicates with the inner chamber 165.
[0089]
　The sub-valve 181 and the annular first valve seat 115 formed on the outer tubular portion 112 of the case member 107 are provided in the second passage 182 on the extension side. The second passage 182 is opened and closed to form a second damping force generation mechanism 183 on the extension side that suppresses the flow of oil liquid from the second passage 182 to the lower chamber 20 to generate a damping force. In other words, in the second damping force generation mechanism 183, the first valve seat 115 is provided on the case member 107. The sub-valve 181 constituting the extension-side second damping force generation mechanism 183 is an extension-side sub-valve. The second damping force generating mechanism 183 including the sub-valve 181 and the first valve seat 115 has the piston rod 21 inserted radially inward, and the lower chamber 20 of the two upper chambers 19 and the lower chamber 20 is inserted. It is placed on the side.
[0090]
　In the second passage 182, when the second damping force generation mechanism 183 is in the open state, the passage in the notch 88 of the disk 82 shown in FIG. 3 has the narrowest passage cross-sectional area among the fixed portions. It is squeezed more than before and after. The passage in the notch 88 of the disk 82 also serves as an orifice 175 in the second passage 182. The orifice 175 is common to the second passages 172 and 182. The orifice 175 is arranged on the upstream side of the sub valve 181 of the oil liquid flow when the sub valve 181 is opened and the oil liquid flows in the second passage 182. In other words, as shown in FIG. 2, the orifice 175 is arranged on the upper chamber 19 side of the sub valve 181 in the second passage 182. The orifice 175 is formed by cutting out a disk 82 that abuts on the piston 18 among the parts constituting the first damping force generation mechanism 41.
[0091]
　The second damping force generation mechanism 183 on the extension side is fixed to both the first valve seat 115 and the sub-valve 181 in contact with the first valve seat 115 so as to communicate the upper chamber 19 and the lower chamber 20 even when they are in contact with each other. No orifice is formed. That is, the second damping force generation mechanism 183 on the extension side does not allow the upper chamber 19 and the lower chamber 20 to communicate with each other if the first valve seat 115 and the sub valve 181 are in contact with each other over the entire circumference. In other words, the second passage 182 is not formed with a fixed orifice that always communicates the upper chamber 19 and the lower chamber 20. The second passage 182 is not a passage that always communicates the upper chamber 19 and the lower chamber 20.
[0092]
　In the shock absorber 1, the upper chamber 19 and the lower chamber 20 have the first damping force generating mechanism 41, 42 and the second damping force generating mechanism 1733 as the flow for passing the oil liquid in the piston 18 in the axial direction at least. Communication is possible only via 183. Therefore, the shock absorber 1 is not provided with a fixed orifice that allows the upper chamber 19 and the lower chamber 20 to always communicate with each other, at least on the passage of the oil liquid that passes in the piston 18 in the axial direction.
[0093]
　The extension-side second passage 182 that can communicate the upper chamber 19 and the lower chamber 20 is the extension-side passage 92 that also allows the upper chamber 19 and the lower chamber 20 to communicate with each other, and the upper chamber 19 side. Except for the passages in the plurality of passage holes 37 and the annular groove 55, the passages are arranged in parallel. In the parallel portion, a first damping force generation mechanism 41 is provided in the first passage 92, and a second damping force generation mechanism 183 is provided in the second passage 182. Therefore, the first damping force generation mechanism 41 and the second damping force generation mechanism 183 on the extension side are arranged in parallel.
[0094]
　As described above, the second damping force generation mechanism 173, 183 is the first annular shape formed on the outer cylinder portion 112 of the bottomed tubular case member 107 having the bottom portion 111, the outer cylinder portion 112, and the inner cylinder portion 113. What is the valve seat 115, the annular disc valve 105 in which the outer peripheral side separating portion 151 on the outer peripheral side is arranged so as to be detachable from the first valve seat 115 of the case member 107, and the first valve seat 115 of the disc valve 105? A second valve seat 135, which is provided on the opposite side and supports the inner peripheral side contacting portion 152 radially inside the outer peripheral side separating portion 151 of the disc valve 105 so as to be detachable, is provided. The second damping force generation mechanism 173 is provided at the end position of the second passage 172. The second damping force generation mechanism 183 is provided at the end position of the second passage 182.
[0095]
　As shown in FIG. 1, the above-mentioned base valve 25 is provided between the bottom member 12 of the outer cylinder 4 and the inner cylinder 3. The base valve 25 includes a base valve member 191 that separates the lower chamber 20 and the reservoir chamber 6, a disk 192 provided on the lower side of the base valve member 191, that is, on the reservoir chamber 6 side, and an upper side, that is, a lower side of the base valve member 191. It has a disc 193 provided on the chamber 20 side, and a mounting pin 194 for mounting the disc 192 and the disc 193 to the base valve member 191.
[0096]
　The base valve member 191 has an annular shape, and the mounting pin 194 is inserted in the center in the radial direction. The base valve member 191 has a plurality of passage holes 195 through which oil and liquid can flow between the lower chamber 20 and the reservoir chamber 6, and is below the passage holes 195 on the radial outside of the base valve member 191. A plurality of passage holes 196 through which oil liquid can flow are formed between the chamber 20 and the reservoir chamber 6. The disk 192 on the reservoir chamber 6 side allows the flow of oil liquid from the lower chamber 20 to the reservoir chamber 6 through the passage hole 195, while allowing the oil liquid to flow from the reservoir chamber 6 to the lower chamber 20 through the passage hole 195. Suppress the flow. The disk 193 allows the flow of oil liquid from the reservoir chamber 6 to the lower chamber 20 through the passage hole 196, while suppressing the flow of the oil liquid from the lower chamber 20 through the passage hole 196 to the reservoir chamber 6.
[0097]
　The disk 192 and the base valve member 191 form a compression valve mechanism 197 on the contraction side that opens a valve in the contraction stroke of the shock absorber 1 to allow oil and liquid to flow from the lower chamber 20 to the reservoir chamber 6 and generate a damping force. ing. The disk 193 constitutes a suction valve mechanism 198 that is opened by the base valve member 191 in the extension stroke of the shock absorber 1 to allow oil liquid to flow from the reservoir chamber 6 into the lower chamber 20. The suction valve mechanism 198 applies oil and liquid from the reservoir chamber 6 to the lower chamber 20 without substantially generating damping force so as to make up for the shortage of the liquid mainly caused by the extension of the piston rod 21 from the cylinder 2. It fulfills the function of flowing.
[0098]
　As shown in FIG. 2, when assembling the piston 18 or the like to the piston rod 21, the annular member 67 and the disc 66 are inserted into the shaft step portion 29 while inserting the screw shaft portion 31 and the mounting shaft portion 28 of the piston rod 21. , Disc 65, a plurality of discs 64, a plurality of discs 63, a disc 62, and a piston 18 are stacked in this order. At this time, the piston 18 is oriented so that the small diameter hole portion 45 is located closer to the shaft step portion 29 than the large diameter hole portion 46. In addition, while inserting the screw shaft portion 31 and the mounting shaft portion 28, the disc 82, the plurality of discs 83, the plurality of discs 84, the disc 101, the disc 102, and the disc 103 are inserted into the piston 18. , The disc 104, the disc valve 105, the plurality of discs 106, and the case member 107 are stacked in this order. At this time, the case member 107 is oriented so that the outer cylinder portion 112 and the inner cylinder portion 113 are located closer to the piston 18 than the bottom portion 111. The case member 107 abuts on the disc 106 at the inner cylinder 113 and the outer annular portion 141 of the disc valve 105 at the outer cylinder 112.
[0099]
　In this state, the nut 108 is screwed into the male screw 32 of the screw shaft portion 31 of the piston rod 21 protruding from the case member 107, and the nut 108 and the shaft step portion 29 are axially oriented on the inner peripheral side thereof. Clamp.
[0100]
　In this state, the inner peripheral side of the main valve 71 is clamped to the inner seat portion 49 of the piston 18 and the disc 65 via the disc 62. At the same time, the main valve 71 abuts on the valve seat portion 50 of the piston 18 over the entire circumference. In this state, the inner peripheral side of the main valve 91 is clamped to the inner seat portion 47 of the piston 18 and the disc 84 via the disc 82. At the same time, the main valve 91 comes into contact with the valve seat portion 48 of the piston 18 over the entire circumference.
[0101]
　In this state, the discs 101 to 104 constituting the second valve seat 135 and the disc valve 105 are clamped to the disc 84 and the disc 106 on the inner peripheral side.
At this time, the disc valve 105 is clamped at the inner annular portion 142. The support portion 143 and the outer annular portion 141 shown in FIG. 4 are not clamped. At the same time, as shown in FIG. 2, the sub-valve 171 of the outer annular portion 141 of the disc valve 105 abuts on the second valve seat 135 at the inner peripheral side separating portion 152 from the side opposite to the piston 18 over the entire circumference. The sub-valve 181 of the outer annular portion 141 abuts on the first valve seat 115 at the outer peripheral side detaching portion 151 from the piston 18 side over the entire circumference.
[0102]
　As described above, the second valve seat 135 is located on the axial bottom 111 side, that is, on the side opposite to the piston 18 with respect to the first valve seat 115. Therefore, the outer annular portion 141 that abuts on the first valve seat 115 and the second valve seat 135 at the same time is deformed in a tapered shape so as to be separated from the piston 18 in the axial direction toward the inner side in the radial direction. In other words, in the outer annular portion 141, the outer peripheral side contacting portion 151 on the first valve seat 115 side is located on the piston 18 side in the axial direction with respect to the inner peripheral side separating portion 152 on the second valve seat 135 side. It deforms in a tapered shape.
[0103]
　Of the first damping force generation mechanism 41 and the second damping force generation mechanism 183 on the extension side, the main valve 91 of the first damping force generation mechanism 41 is configured by stacking a plurality of disks 83. Therefore, the rigidity is higher and the valve opening pressure is higher than that of the sub valve 181 of the second damping force generation mechanism 183 composed of one disc valve 105. Therefore, in the extension stroke, in the extremely low speed region where the piston speed is lower than the predetermined value, the second damping force generation mechanism 183 opens with the first damping force generating mechanism 41 closed. In the normal speed region where the piston speed is equal to or higher than this predetermined value, both the first damping force generation mechanism 41 and the second damping force generation mechanism 183 open. The sub-valve 181 is an extremely low-speed valve that opens in a region where the piston speed is extremely low and generates a damping force.
[0104]
　That is, in the extension stroke, the piston 18 moves to the upper chamber 19 side, so that the pressure in the upper chamber 19 increases and the pressure in the lower chamber 20 decreases. However, since neither the first damping force generating mechanism 41, 42 nor the second damping force generating mechanism 173, 183 has a fixed orifice, the oil liquid does not flow until the second damping force generating mechanism 183 is opened. Therefore, in the extension stroke when the piston speed is less than the first predetermined value v1, the damping force rises sharply. The piston speed is a region higher than the first predetermined value v1 opened by the second damping force generation mechanism 183, and is a very low speed region lower than the second predetermined value v2 faster than the first predetermined value v1. In (v1 or more and less than v2), the second damping force generation mechanism 183 opens with the first damping force generating mechanism 41 closed.
[0105]
　That is, the sub-valve 181 is separated from the first valve seat 115, and the upper chamber 19 and the lower chamber 20 are communicated with each other by the second passage 182 on the extension side. Therefore, the oil liquid in the upper chamber 19 flows into the passages in the plurality of passage holes 37 and the annular groove 55 of the piston 18, the passage 175, the passage in the large diameter hole portion 46 of the piston 18, and the passage of the piston rod 21. The piston rod passage portion 51 in the notch 30, the passage in the large-diameter hole portion 127 of the case member 107, the chamber passage portion 131 in the passage groove 121, the case inner chamber 165, the sub valve 181 and the first valve seat 115. It flows to the lower chamber 20 through the passage between them. As a result, even in an extremely low speed region (v1 or more and less than v2) in which the piston speed is lower than the second predetermined value v2, the damping force of the valve characteristic (the characteristic in which the damping force is substantially proportional to the piston speed) can be obtained.
[0106]
　In the extension stroke, in the normal speed region where the piston speed is the second predetermined value v2 or more, the first damping force generating mechanism 41 opens while the second damping force generating mechanism 183 remains open. That is, the sub-valve 181 is separated from the first valve seat 115, and the oil liquid flows from the upper chamber 19 to the lower chamber 20 in the second passage 182 on the extension side. At this time, the flow of the oil liquid is throttled by the orifice 175 provided on the downstream side of the main valve 91 in the second passage 182, so that the pressure applied to the main valve 91 increases and the differential pressure increases. The main valve 91 is separated from the valve seat portion 48, and the oil liquid flows from the upper chamber 19 to the lower chamber 20 in the first passage 92 on the extension side. Therefore, the oil liquid in the upper chamber 19 flows into the lower chamber 20 via the passage in the plurality of passage holes 37 and the annular groove 55 and the passage between the main valve 91 and the valve seat portion 48.
[0107]
　In the extension stroke, in the normal speed region where the piston speed is the second predetermined value v2 or more, the differential pressure between the upper chamber 19 and the lower chamber 20 is larger than the low speed region of the first predetermined value v1 or more and less than the second predetermined value v2. However, since the first passage 92 does not have a throttle due to the orifice, the oil liquid can be flowed through the first passage 92 at a large flow rate by opening the main valve 91. By this and by narrowing the second passage 182 with the orifice 175, it is possible to suppress the deformation of the outer annular portion 141 on the sub valve 181 side.
[0108]
　At this time, pressure in opposite directions is applied to the closed sub-valve 171 from the lower chamber 20 and the case inner chamber 165. Even if the differential pressure between the upper chamber 19 and the lower chamber 20 becomes large, the lower chamber 20 and the case inner chamber 165 communicate with each other by opening the sub valve 181. Since the orifice 175 is formed on the upstream side of the sub valve 171 in the second passage 182, the pressure rise in the case inner chamber 165 becomes gentle with respect to the pressure rise in the upper chamber 19, and the case inner chamber 165 and the lower chamber 20 are formed. Suppresses the increase in pressure difference with. Therefore, it is possible to prevent the pressure difference between the case inner chamber 165 and the lower chamber 20 received by the closed sub-valve 171 side of the outer annular portion 141 from becoming large. Therefore, it is possible to suppress the application of a large back pressure from the case inner chamber 165 side to the lower chamber 20 side to the sub valve 171 side of the outer annular portion 141. Therefore, the deformation of the outer annular portion 141 on the sub valve 171 side can be suppressed.
[0109]
　The shock absorber 1 is provided with a flow path for flowing oil liquid from the upper chamber 19 to the lower chamber 20 in parallel in the extension stroke of the first passage 92 and the second passage 182, and the main valve 91 and the sub valve 181 are provided in parallel. There is. The orifice 175 is connected in series with the sub valve 181.
[0110]
　As described above, in the extension stroke, in the normal speed region where the piston speed is the second predetermined value v2 or more, the main valve 91 is opened so that the oil liquid can flow at a large flow rate through the first passage 92. .. As a result, the flow rate flowing through the passage between the sub valve 181 and the first valve seat 115 is reduced. Therefore, the valve rigidity of the sub valve 181 can be reduced. Therefore, for example, it is possible to reduce the rate of increase in the damping force with respect to the increase in the piston speed in the normal speed region (v2 or more). In other words, the slope of the increase rate of the damping force on the extension side with respect to the increase in the piston speed in the normal speed region (v2 or more) can be laid down more than in the extremely low speed region (less than v2). As a result, the degree of freedom in design can be expanded.
[0111]
　Of the first damping force generation mechanism 42 and the second damping force generation mechanism 173 on the contraction side, the main valve 71 of the first damping force generation mechanism 42 is configured by stacking a plurality of disks 63 and 64. Therefore, the rigidity is higher and the valve opening pressure is higher than that of the sub valve 171 of the second damping force generation mechanism 173 composed of one disc valve 105. Therefore, in the contraction stroke, in the extremely low speed region where the piston speed is lower than the predetermined value, the second damping force generation mechanism 173 opens with the first damping force generating mechanism 42 closed, and the piston speed is the predetermined value. In the above normal speed region, both the first damping force generation mechanism 42 and the second damping force generation mechanism 173 open.
The sub valve 171 is an extremely low speed valve that opens in a region where the piston speed is extremely low and generates a damping force.
[0112]
　That is, in the contraction stroke, the piston 18 moves to the lower chamber 20 side, so that the pressure in the lower chamber 20 increases and the pressure in the upper chamber 19 decreases. Since neither the first damping force generating mechanism 41, 42 nor the second damping force generating mechanism 173, 183 has a fixed orifice, the oil liquid does not flow until the second damping force generating mechanism 173 is opened. Therefore, the damping force rises sharply. In the region where the piston speed is higher than the third predetermined value at which the second damping force generation mechanism 173 opens, and in the extremely low speed region where the piston speed is faster than the third predetermined value and lower than the fourth predetermined value. The second damping force generation mechanism 173 opens with the first damping force generation mechanism 42 closed.
[0113]
　That is, the sub-valve 171 is separated from the second valve seat 135, and the lower chamber 20 and the upper chamber 19 are communicated with each other through the second passage 172 on the contraction side. Therefore, the oil liquid in the lower chamber 20 is the passage between the sub valve 171 and the second valve seat 135, the passage between the outer annular portion 141 and the inner annular portion 142 of the disc valve 105, the case inner chamber 165, and the case. The passage in the chamber passage portion 131 and the large-diameter hole portion 127 in the passage groove 121 of the member 107, the piston rod passage portion 51 in the passage notch 30 of the piston rod 21, and the large-diameter hole portion 46 of the piston 18. It flows into the upper chamber 19 through the passage, the orifice 175, and the passage in the annular groove 55 of the piston 18 and in the plurality of passage holes 37. As a result, the damping force of the valve characteristic (the characteristic in which the damping force is substantially proportional to the piston speed) can be obtained even in the extremely low speed region where the piston speed is lower than the fourth predetermined value.
[0114]
　In the contraction stroke, in the normal speed region where the piston speed is equal to or higher than the fourth predetermined value, the first damping force generating mechanism 42 opens while the second damping force generating mechanism 173 remains open. That is, the sub-valve 171 is separated from the second valve seat 135, and the oil liquid flows from the lower chamber 20 to the upper chamber 19 in the second passage 172 on the contraction side. At this time, since the flow rate of the oil liquid is throttled by the orifice 175 in the second passage 172, the differential pressure generated in the main valve 71 becomes large. The main valve 71 is separated from the valve seat portion 50, and the oil liquid flows from the lower chamber 20 to the upper chamber 19 in the first passage 72 on the contraction side. Therefore, the oil liquid in the lower chamber 20 flows through the passages in the plurality of passage holes 39 and the annular groove 56, and the passages between the main valve 71 and the valve seat portion 50. As a result, a damping force having valve characteristics (damping force is substantially proportional to the piston speed) can be obtained even in a normal speed region in which the piston speed is equal to or higher than the fourth predetermined value. The rate of increase in the damping force on the contraction side with respect to the increase in the piston speed in the normal speed region is lower than the rate of increase in the damping force on the contraction side with respect to the increase in the piston speed in the extremely low speed region. In other words, the slope of the rate of increase in the damping force on the contraction side with respect to the increase in piston speed in the normal speed region can be laid down more than in the extremely low speed region.
[0115]
　In the contraction stroke, in the normal speed region where the piston speed is equal to or higher than the fourth predetermined value, the differential pressure between the lower chamber 20 and the upper chamber 19 becomes larger than in the low speed region. Since the first passage 72 is not throttled by the orifice, the oil liquid can be flowed through the first passage 72 at a large flow rate by opening the main valve 71. As a result, the flow rate flowing through the sub valve 171 becomes small, so that the valve rigidity of the sub valve 171 can be reduced. Therefore, the piston speed can reduce the damping force in the normal speed region, and the degree of freedom in design can be expanded.
[0116]
　At this time (when the piston speed is high), the differential pressure between the lower chamber 20 and the upper chamber 19 becomes large, but by narrowing the second passage 172 with the orifice 175, the upper chamber 19 is communicated with the upper chamber 19 via the orifice 175. Since the pressure in the inner chamber 165 is the pressure between the lower chamber 20 and the upper chamber 19, it is possible to prevent the differential pressure from the lower chamber 20 from becoming too large. By opening the main valve 71 and allowing the oil liquid to flow at a large flow rate through the first passage 72, it is possible to suppress the deformation of the outer annular portion 141 on the sub valve 171 side.
[0117]
　At this time, pressure in opposite directions is applied to the closed sub-valve 181 from the lower chamber 20 and the case inner chamber 165. Although the differential pressure between the lower chamber 20 and the upper chamber 19 is large, the lower chamber 20 and the case inner chamber 165 communicate with each other by opening the sub valve 171 and an orifice between the case inner chamber 165 and the upper chamber 19. 175 is provided. Therefore, it is possible to prevent the pressure in the case inner chamber 165 from dropping too much, and it is possible to raise the pressure in the case inner chamber 165 as the pressure in the lower chamber 20 rises. Therefore, the differential pressure generated on the upstream side and downstream side surfaces of the sub valve 181 is small, and it is possible to suppress the application of a large back pressure from the lower chamber 20 side to the case inner chamber 165 side on the sub valve 181 side of the outer annular portion 141. ..
[0118]
　In the above shock absorber 1, a flow path for flowing oil liquid from the lower chamber 20 to the upper chamber 19 is provided in parallel between the first passage 72 and the second passage 172 in the contraction stroke, and the main valve 71 and the sub valve 171 are arranged in parallel. It is provided. The orifice 175 is connected in series with the sub valve 171 in the second passage 172.
[0119]
　In the contraction stroke, the damping force characteristic by the damping valve mechanism 197 is also combined.
[0120]
　In the extension stroke, the differential pressure between the upper chamber 19 and the lower chamber 20 becomes large in the normal speed region where the piston speed is equal to or higher than the second predetermined value. The lower chamber 20 and the case inner chamber 165 are communicated with each other by opening the sub valve 181 and the pressure increase of the case inner chamber 165 can be suppressed by the orifice 175 formed on the upstream side of the sub valve 171. Therefore, it is possible to suppress the deformation of the outer annular portion 141 due to the back pressure on the sub valve 171 side. In the contraction stroke, the differential pressure between the lower chamber 20 and the upper chamber 19 becomes larger in the normal speed region where the piston speed is equal to or higher than the fourth predetermined value than in the low speed region. Deformation of the sub-valve 171 can be suppressed by flowing the oil liquid at a large flow rate in the first passage 72 and by narrowing the downstream side of the sub-valve 171 of the second passage 172 with the orifice 175. Therefore, the durability of the sub valve 171 can be improved.
[0121]
　In the extension stroke, the differential pressure between the upper chamber 19 and the lower chamber 20 becomes larger in the normal speed region where the piston speed is equal to or higher than the second predetermined value than in the low speed region. Deformation of the outer annular portion 141 on the sub-valve 181 side can be suppressed by flowing the oil liquid at a large flow rate in the first passage 92 and by narrowing the second passage 182 with the orifice 175. In the contraction stroke, the differential pressure between the lower chamber 20 and the upper chamber 19 becomes large in the normal speed region where the piston speed is equal to or higher than the fourth predetermined value. The lower chamber 20 and the case inner chamber 165 are communicated with each other by opening the sub valve 171. Moreover, the case inner chamber 165 is an orifice 175 provided between the upper chamber 19 and the flow of oil liquid to the upper chamber 19. Is squeezed. Therefore, the differential pressure between the lower chamber 20 and the case inner chamber 165 is small, and deformation of the outer annular portion 141 due to the back pressure on the sub valve 181 side can be suppressed. Therefore, the durability of the sub valve 181 can be improved.
[0122]
　Since the second damping force generation mechanism 173, 183 that is independent in the contraction stroke and the expansion stroke is provided, the degree of freedom in setting the damping force characteristic is increased.
[0123]
　The above-mentioned Patent Documents 1 to 3 describe a shock absorber having two valves that open in the same stroke. Having two valves that open in the same stroke has problems such as a complicated structure, an increase in the number of parts, and an increase in the axial length. In such a shock absorber, simplification of the structure is required.
[0124]
　The shock absorber 1 of the first embodiment has two first damping force generation mechanisms 41 and a second damping force generation mechanism 183 that open the valve in the extension stroke. The shock absorber 1 of the first embodiment has two first damping force generation mechanisms 42 and a second damping force generation mechanism 173 that open the valve in the contraction stroke. Even with such a configuration, the second damping force generation mechanism 173, 183 is an annular number formed on the outer cylinder portion 112 of the bottomed tubular case member 107 having the bottom portion 111 and the outer cylinder portion 112. The 1-valve seat 115, the annular disc valve 105 in which the outer peripheral side separating portion 151 on the outer peripheral side is arranged so as to be detachable from the first valve seat 115 of the case member 107, and the first valve seat 115 of the disc valve 105. Is provided on the opposite side, and has a structure including a second valve seat 135 that supports the inner peripheral side contacting portion 152 radially inside the outer peripheral side separating portion 151 of the disc valve 105 so as to be detachable. There is.
Therefore, the structure can be simplified, the number of parts can be reduced, and the length in the axial direction can be suppressed.
[0125]
　The disc valve 105 constituting the second damping force generation mechanism 173, 183 has an outer annular portion 141 that is detachably arranged on the first valve seat 115 and the second valve seat 135, and an inner annular portion through which the piston rod 21 is inserted. It has a portion 142 and a support portion 143 connecting them. Therefore, while the inner annular portion 142 and the support portion 143 suppress the positional deviation in the radial direction of the outer annular portion 141 that opens and closes in contact with the first valve seat 115 and the second valve seat 135, the outer annular portion 141 is used. It is possible to operate in almost the same way as a free valve that is not connected to the part of.
[0126]
　The two support portions 143 have two outer connecting portions 161 arranged on the same side of the center in the radial direction of the disc valve 105 at intervals in the circumferential direction of the disc valve 105. Connected to 141. The two support portions 143 have two inner connecting portions 162 arranged at intervals in the circumferential direction of the disc valve 105 on the same opposite side of the center in the radial direction of the disc valve 105. Connected to 142. Two connecting arm portions 163 are provided so as to connect the outer connecting portion 161 near the circumferential direction of the disc valve 105 and the inner connecting portion 162. Moreover, the distance between the two inner connecting portions 162 is wider than the distance between the two outer connecting portions 161. Therefore, the support portion 143 operates the outer annular portion 141 in the same manner as the free valve while appropriately suppressing the positional deviation of the outer annular portion 141 with respect to the inner annular portion 142, that is, the piston rod 21 and the case member 107 in the radial direction. Can be done well.
[0127]
　Since the second valve seat 135 that supports the disc valve 105 has a flexible configuration, the rigidity of the support point of the disc valve 105 can be changed, and the disc valve 105 is supported by the second valve seat 135. The degree of freedom in tuning of the second damping force generation mechanism 183 that opens at is increased.
[0128]
　The case member 107 has a case portion 167 that forms a chamber passage portion 131 and a case inner chamber 165, and a washer portion 166 that covers an incompletely threaded portion 109 of the piston rod 21. Therefore, the number of parts can be further reduced as compared with the case where these are separated.
[0129]
　An orifice 175 is arranged on the upstream side of the sub-valve 181 of the flow during the extension stroke when the sub-valve 181 of the second passage 182 is opened. As a result, the orifice 175 throttles the flow of the oil liquid flowing from the lower chamber 20 into the case inner chamber 165 and flowing to the upper chamber 19 by opening the sub valve 171 from the lower chamber 20 during the contraction stroke. Therefore, the differential pressure between the case inner chamber 165 and the lower chamber 20 becomes smaller, and the closed sub-valve 181 that receives the back pressure from the lower chamber 20 receives the same pressure as the lower chamber 20 from the case inner chamber 165. Therefore, the back pressure (differential pressure) received is suppressed. Therefore, the durability of the sub valve 181 can be improved.
[0130]
　The second passages 172 and 182 are not always communicating passages and do not have a always communicating fixed orifice. Therefore, the effect of suppressing the back pressure received by the sub valve 181 is high.
[0131]
　The orifice 175 is formed by cutting out the disk 82 that abuts on the piston 18 in the first damping force generating mechanism 41 on the extension side. Therefore, the orifice 175 can be easily formed.
[0132]
　A part of each of the second passages 172 and 182 is formed by cutting out the piston rod 21. Therefore, the second passages 172 and 182 can be easily formed.
[0133]
　The differential pressure between the case inner chamber 165 and the lower chamber 20 does not increase in both expansion and contraction strokes. Therefore, it becomes possible to use a thin pressed part as the disc valve 105, which is advantageous in terms of manufacturability and weight reduction of the disc valve 105.
[0134]
　Instead of the disc valve 105, for example, the disc valve 105a of the modification 1 as shown in FIG. 5 may be used. The disc valve 105a has an outer annular portion 141 and an inner annular portion 142 similar to the disc valve 105, and has two support portions 143a that are partially different from the support portion 143.
[0135]
　The two support portions 143a have two outer connection portions 161a arranged on the same straight line passing through the center of the disc valve 105a. These outer connecting portions 161a are connected to the outer annular portion 141. The two outer connecting portions 161a are arranged so as to be 180 degrees out of phase with each other in the circumferential direction of the outer annular portion 141. Both of the two outer connecting portions 161a project radially inward from the inner peripheral edge portion of the outer annular portion 141 to the outer annular portion 141.
[0136]
　The two support portions 143a have two inner connecting portions 162a arranged on the same straight line passing through the center of the disc valve 105a. These inner connecting portions 162a are connected to the inner annular portion 142. The two inner connecting portions 162a are arranged so as to be 180 degrees out of phase with each other in the circumferential direction of the inner annular portion 142. Both of the two inner connecting portions 162a project from the outer peripheral edge portion of the inner annular portion 142 to the radial outer side of the inner annular portion 142. The distance between the two outer connecting portions 161a and one of the two inner connecting portions 162a in the circumferential direction is closer than that of the other. In other words, the distance between the two inner connecting portions 162a and one of the two outer connecting portions 161a in the circumferential direction is closer than that of the other.
[0137]
　On the one hand, the distance between the outer connection portion 161a far away in the circumferential direction of the disc valve 105a and the inner connection portion 162a is equivalent to the distance between the outer connection portion 161a far away in the circumferential direction of the disc valve 105a and the inner connection portion 162a. ing.
[0138]
　Further, the two support portions 143a are provided with two connecting arm portions 163a so as to connect the outer connecting portion 161a and the inner connecting portion 162a which are distant in the circumferential direction of the disc valve 105a. That is, the disc valve 105a is provided with one connecting arm portion 163a for connecting the one outer connecting portion 161a and the one inner connecting portion 162a, which are distant in the circumferential direction of the disc valve 105a. The outer connecting portion 161a, the inner connecting portion 162a, and the connecting arm portion 163a form one of the supporting portions 143a. The disc valve 105a is provided with the other connecting arm portion 163a that connects the other outer connecting portion 161a and the other inner connecting portion 162a, which are distant in the circumferential direction of the disc valve 105a. The outer connecting portion 161a, the inner connecting portion 162a, and the connecting arm portion 163a form the other support portion 143a.
[0139]
　The two connecting arm portions 163a extend in an arc shape along the inner peripheral surface of the outer annular portion 141 and the outer peripheral surface of the inner annular portion 142. It is arranged on the same circle concentrically with the outer annular portion 141 and the inner annular portion 142. The two connecting arm portions 163a have the same radial distance from the inner peripheral surface of the outer annular portion 141 and the radial distance from the outer peripheral surface of the inner annular portion 142.

WE CLAIMS

[Claim 1]A cylinder in which a working fluid is sealed, a piston
　slidably provided in the cylinder and dividing the inside of the cylinder into two chambers,
　and a piston rod connected to the piston and extended to the outside of the cylinder. ,
　The first passage and the second passage through which the working fluid flows out from the chamber on the upstream side in the cylinder to the chamber on the downstream side due to the movement of the piston, and the first passage
　formed on the piston. , A first damping force generating mechanism that generates a damping force and a
　piston rod are inserted and arranged on the chamber side of one of the two chambers, and are provided in the second passage parallel to the first passage. The second damping force generation mechanism has a
　second damping force generation mechanism that generates a damping force , and the second damping force generation mechanism is
　an annular shape formed in the cylinder portion of a bottomed tubular case member having a cylinder portion and a bottom portion. The first valve seat of the
　case member, the annular disc valve in which the detachable portion on the outer peripheral side is arranged so as to be detachable from the first valve seat of the case member, and the side of the disc valve
　opposite to the first valve seat. A second valve seat that is provided in the disk valve and supports the inside of the disc valve in a radial direction so as to be detachable, and
　the second passage
　cuts out or penetrates the piston rod. A piston rod passage portion to be formed,
　a chamber passage portion communicating from the piston rod passage portion to the case inner chamber between the bottom portion of the case member and the disc valve, and a chamber passage portion.
In
　a region where the piston speed is low, the first damping force generation mechanism is closed and the second damping force generation mechanism is opened. In a
　speed region where the piston speed is higher than the low speed , the first damping force generation mechanism is opened . A shock absorber in which both the 1 damping force generation mechanism and the 2nd damping force generation mechanism open.
[Claim 2]
　The disc valve connects
　an outer annular portion that is detachably arranged on the first valve seat of the case member,
　an inner annular portion through which the piston rod is inserted, and the
　outer annular portion and the inner annular portion.
　The second valve seat is provided with a support portion, and the second valve seat is provided so as to be able to cut off between the outer annular portion and the inner annular portion by inserting the piston rod. Shock absorber.
[Claim 3]
　Two
　support portions of the
　disc valve are provided, and the support portions are arranged on the same side of the center in the radial direction of the disc valve and at intervals in the circumferential direction of the disc valve. The outer connection portion of the place is connected to the outer annular portion, and
　two inner connections are arranged on the same opposite side of the center in the radial direction of the disc valve and spaced apart from each other in the circumferential direction of the disc valve. The portions are connected to the inner annular portion, and
　two connecting arm portions are provided so as to connect the outer connection portion near the circumferential direction of the disc valve and the inner connection portion, and the two inner portions are provided. The shock absorber according to claim 2, wherein the distance between the connections is wider than the distance between the two outer connections.
[Claim 4]
　Two
　support portions of the
　disc valve are provided, and in the support portion, two outer connection portions arranged on the same straight line passing through the center of the disc valve are connected to the outer annular portion, and the
　disc is connected. Two inner connecting portions arranged on the same straight line passing through the center of the valve are connected to the inner annular portion, and the
　outer connecting portion and the inner connecting portion far from the circumferential direction of the disc valve are connected to each other. The shock absorber according to claim 2, wherein the shock absorber is provided with two connecting arms.
[Claim 5]
　The shock absorber according to any one of claims 1 to 4, wherein the second valve seat supporting the disc valve has a flexible configuration.
[Claim 6]
　The
　one according to any one of claims 1 to 5, wherein the case member has a chamber passage portion, a case portion forming the case inner chamber, and a washer portion covering an incompletely threaded portion of the piston rod. Shock absorber.
[Claim 7]
　The shock absorber according to claim 6, wherein the case portion and the washer portion are formed separately.
[Claim 8]
　The shock absorber according to any one of claims 1 to 6, wherein the tubular portion is provided with a restricting portion that regulates the radial movement of the disc valve.