JP2017096453A - Buffer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a buffer capable of stabilizing attenuation force characteristics.SOLUTION: A buffer includes: a first valve body 41 through the inside of which a part of a passage 118 in which working fluid starts flowing with slide of a piston 16 penetrates; a first disc 42 installed so as to be able to sit on a first sheet 62 protrusively provided in the first valve body 41; a bottomed cylindrical second valve body 71 that has a cylindrical part 81 and a bottom part 82 and through the inside of which a part of the passage 118 penetrates; and a second disc 73 installed so as to be able to sit on a second sheet 93 protrusively provided in the second valve body 71. An outer peripheral side of the first valve body 41 and the cylindrical part 81 of the second valve body 71 are connected through a seal member 77.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a shock absorber.

  In order to provide the first valve and the second valve in series along the flow path of the working fluid in the piston body, there is a shock absorber in which the piston body is composed of two parts (see, for example, Patent Document 1).

JP-A-2015-132313

  In a shock absorber, in order to couple two parts while restricting leakage of a working fluid from a coupling part, the other part is pressed into one part. However, the press-fitting may cause distortion in parts, and the damping force characteristic may become unstable.

  Therefore, an object of the present invention is to provide a shock absorber that can stabilize the damping force characteristics.

  To achieve the above object, the present invention provides a first valve body in which a part of a passage through which a working fluid flows by sliding of a piston penetrates the inside, and a first seat projecting from the first valve body. A first disk that is seated on the bottom, a cylindrical second valve body that has a cylindrical portion and a bottom portion, and a portion of the passage passes through the inside of the first disk, and protrudes from the second valve main body A second disc mounted on the second seat so as to be seatable, and the outer peripheral side of the first valve body of the first valve body and the cylindrical portion of the second valve body serve as a sealing member. It was set as the structure fitted through.

  According to the present invention, the damping force characteristic can be stabilized.

It is sectional drawing which shows the buffer of 1st Embodiment which concerns on this invention. It is a fragmentary sectional view showing an important section of a buffer of a 1st embodiment concerning the present invention. It is a fragmentary sectional view showing an important section of a buffer of a 2nd embodiment concerning the present invention.

“First Embodiment”
1st Embodiment which concerns on this invention is described based on FIG. 1 and FIG. In the following, for convenience of explanation, the upper side in the drawing is referred to as “upper” and the lower side in the drawing is referred to as “lower”.

  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 liquid (not shown) as a working liquid is enclosed. The cylinder 2 has a cylindrical metal inner cylinder 3 and a bottomed cylindrical outer cylinder 4 that is concentrically provided so as to cover the inner cylinder 3 with a larger diameter than the inner cylinder 3. A reservoir chamber 6 is formed between the inner cylinder 3 and the outer cylinder 4.

  The outer cylinder 4 includes a cylindrical metal body member 11 and a metal bottom member 12 that closes a lower portion of the body member 11. A mounting eye 13 is fixed to the bottom member 12 on the outer side opposite to the body member 11.

  The shock absorber 1 includes a piston 16 slidably fitted in the inner cylinder 3 of the cylinder 2. The piston 16 provided in the inner cylinder 3 includes an upper chamber 17 (one side chamber) on one side in the axial direction of the piston 16 and a lower chamber 18 on the other side in the axial direction of the piston 16. It is divided into (other side rooms). Oil liquid as working fluid is sealed in the upper chamber 17 and the lower chamber 18 in the inner cylinder 3, and oil liquid and gas as working fluid are placed in the reservoir chamber 6 between the inner cylinder 3 and the outer cylinder 4. And are enclosed.

  The shock absorber 1 includes a metal piston rod 21 having one end disposed in the inner cylinder 3 of the cylinder 2 and connected to the piston 16 and the other end extending to the outside of the cylinder 2. The piston 16 and the piston rod 21 move together. In the expansion stroke in which the piston rod 21 increases the amount of protrusion from the cylinder 2, the piston 16 moves to the upper chamber 17 side. In the contraction stroke in which the piston rod 21 decreases the amount of protrusion from the cylinder 2, the piston 16 moves downward. It moves to the chamber 18 side.

  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 attached to the outer cylinder 4 on the upper side, which is the outer side of the cylinder 2, relative to the rod guide 22. Yes. Both the rod guide 22 and the seal member 23 are annular. The piston rod 21 is slidably inserted inside the rod guide 22 and the seal member 23, and extends outside the cylinder 2 via the rod guide 22 and the seal member 23. The upper chamber 17 is formed between the piston 16 in the inner cylinder 3 and the rod guide 22.

  Here, 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 the outer peripheral portion thereof, and is in sliding contact with the outer peripheral portion of the piston rod 21 that moves in the axial direction at the inner peripheral portion thereof. This prevents the high-pressure gas and oil liquid in the inner reservoir chamber 6 from leaking to the outside.

  The rod guide 22 has a step shape in which the outer peripheral portion has a larger diameter at the upper portion than the lower portion. The rod guide 22 is fitted to the inner peripheral portion at the upper end of the inner tube 3 at the lower portion of the small diameter, and the outer tube at the upper portion of the large diameter. 4 is fitted to the inner periphery of the upper part. A base valve 25 that defines a lower chamber 18 and a reservoir chamber 6 is installed on the bottom member 12 of the outer cylinder 4, and the inner peripheral portion of the lower end of the inner cylinder 3 is fitted to the base valve 25. ing. The upper end portion of the outer cylinder 4 is caulked inward in the radial direction to form a caulking portion 26, and the caulking portion 26 and the rod guide 22 sandwich the seal member 23. The lower chamber 18 is formed between the piston 16 in the inner cylinder 3 and the base valve 25.

  The piston rod 21 has a main shaft portion 31 and a mounting shaft portion 32 having a smaller diameter than the main shaft portion 31, and an end portion of the main shaft portion 31 on the mounting shaft portion 32 side is a shaft step portion 33 that extends in the direction perpendicular to the axis. ing. The attachment shaft portion 32 is disposed in the cylinder 2, and a male screw 34 is formed at the end opposite to the main shaft portion 31. The piston 16 is fastened to the mounting shaft portion 32 by a metal nut 35 screwed into the male screw 34. In other words, the piston rod 21 is fastened to the piston 16 by the nut 35.

  In the shock absorber 1, for example, a protruding portion of the piston rod 21 from the cylinder 2 is arranged at the upper part and supported by the vehicle body, and 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. When the wheels vibrate as the vehicle travels, the positions of the cylinder 2 and the piston rod 21 change relatively with the vibrations, but the change is suppressed by the fluid resistance of the flow path formed in the piston 16.

  As shown in FIG. 2, the piston 16 is configured by stacking a regulating member 37, a contact disk 38, a small-diameter disk 39, and a plurality of single disks in order from the axial step 33 side in the axial direction. A valve disk 40, a piston body 41 (first valve body), a valve disk 42 (first disk) configured by stacking a plurality of single disks, and a stack of single disks. A small-diameter disk 43. The restriction member 37, the contact disk 38, the small diameter disk 39, the valve disk 40, the piston body 41, the valve disk 42, and the small diameter disk 43 are all made of metal. The piston 16 has an annular belt-shaped synthetic resin sliding contact member 44 attached to the outer peripheral surface of the piston body 41 and in sliding contact with the inner peripheral surface of the inner cylinder 3.

  The restricting member 37 has an annular shape, and the attachment shaft portion 32 is fitted on the inner peripheral side. The regulating member 37 has an outer diameter larger than the outer diameter of the shaft step portion 33. The restricting member 37 is thinner than the contact disk 38, the small diameter disk 39, the single disk constituting the valve disk 40, the single disk constituting the valve disk 42, and the single disk constituting the small diameter disk 43. It is thick and highly rigid.

  The contact disk 38 has an annular shape, and the mounting shaft portion 32 is fitted on the inner peripheral side. The contact disk 38 has an outer diameter larger than the outer diameter of the regulating member 37. The small-diameter disk 39 has an annular shape, and the attachment shaft portion 32 is fitted on the inner peripheral side. The small diameter disk 39 has an outer diameter smaller than the outer diameter of the regulating member 37.

  In the valve disk 40, all the single disks constituting the disk disk 40 have an annular shape, and the mounting shaft portion 32 is fitted to the inner peripheral side. The valve disk 40 has an outer diameter that increases toward the piston body 41 in the axial direction. The valve disc 40 has a maximum outer diameter, which is the outer diameter of the end portion on the piston body 41 side in the axial direction, larger than the outer diameter of the contact disc 38, and the end portion on the small diameter disc 39 side in the axial direction. The minimum outer diameter, which is the outer diameter, is larger than the outer diameter of the small-diameter disk 39.

  The piston body 41 is formed in an annular shape at the center in the radial direction so that a fitting hole 50 for fitting the mounting shaft portion 32 of the piston rod 21 penetrates in the axial direction. The piston body 41 has a linear passage 51 extending in the axial direction outside the radial fitting hole 50 and an axial direction extending outside the radial fitting hole 50. And a straight passage 52 is formed. A plurality of passages 51 are formed in the piston body 41 at equal intervals in the circumferential direction (only one is shown because of the cross-sectional view), and a plurality of passages 52 are also formed in the piston body 41 at equal intervals in the circumferential direction (drawings). Is shown only in one place because of its cross-sectional shape). The passages 51 and the passages 52 are alternately arranged in the circumferential direction of the piston body 41.

  Further, the piston body 41 has an annular passage 53 that forms a ring over the entire circumference of the piston body 41 so as to communicate with a plurality of passages 51 at the end on the valve disk 40 side in the axial direction, and an axial valve disk 42 side. An annular passage 54 having an annular shape over the entire circumference of the piston body 41 is formed so as to connect the plurality of passages 52 at the end of the piston body 41.

  By forming the annular passage 53, an annular inner seat 56 inside the annular passage 53 in the radial direction of the piston body 41 and the annular passage 53 are arranged at the end of the piston body 41 on the valve disk 40 side in the axial direction. Both outer annular outer sheets 57 are formed so as to protrude in the axial direction of the piston body 41. In other words, on the valve disc 40 side of the piston body 41, an annular outer seat 57 and an annular inner seat 56 radially inward of the outer seat 57 project in the axial direction. In the plurality of passages 52, the opening on the valve disk 40 side is located on the radially outer side than the opening on the valve disk 42 side, and is opened on the radially outer side than the outer seat 57.

  The valve disk 40 has a maximum outer diameter, which is the outer diameter of the end portion on the piston body 41 side in the axial direction, substantially the same as the outer diameter of the end surface of the outer seat 57 on the valve disk 40 side. Therefore, the valve disc 40 is placed so as to be seated on the inner seat 56 and the outer seat 57. The valve disc 40 can be detached from and seated on the outer seat 57. The abutting disk 38 abuts against and regulates a predetermined deformation or more when the valve disk 40 is separated from the outer seat 57. The valve disc 40 is formed with a fixed orifice 58 that allows the upper chamber 17 and the annular passage 53 to communicate with each other even in contact with the outer seat 57.

  By forming the annular passage 54, the end of the piston body 41 on the valve disk 42 side in the axial direction is more than the inner seat 61 and the annular passage 54 inside the annular passage 54 in the radial direction of the piston body 41. Both outer outer sheets 62 (first sheets) are provided so as to protrude in the axial direction of the piston body 41. In other words, on the valve disc 42 side of the piston body 41, an annular outer sheet 62 and an annular inner sheet 61 radially inward of the outer sheet 62 are projected in the axial direction.

  In the valve disc 42, all of the single discs constituting the valve disc 42 have an annular shape, and the mounting shaft portion 32 is fitted on the inner peripheral side. The valve disk 42 has an outer diameter that increases toward the piston body 41 in the axial direction. The valve disk 42 has a maximum outer diameter, which is the outer diameter of the end portion on the piston body 41 side in the axial direction, slightly larger than the outer diameter of the end surface of the outer seat 62 on the valve disc 42 side. The outer seat 62 is slidably mounted. The valve disc 42 can be seated on and off the outer seat 62. The valve disc 42 is formed with a fixed orifice 63 that allows the annular passage 54 to communicate with the outer side of the valve disc 42 even when the valve disc 42 is in contact with the outer seat 62. In the small-diameter disk 43, each of the single disks constituting the disk 43 has an annular shape, and the mounting shaft portion 32 is fitted on the inner peripheral side. The small diameter disk 43 has an outer diameter smaller than the minimum outer diameter that is the outer diameter of the end of the valve disk 42 on the small diameter disk 43 side.

  A mounting base portion 65 is formed on the outer periphery of the piston body 41 so as to be biased toward the valve disc 40 in the axial direction, and the sliding contact member 44 is mounted on the mounting base portion 65. A fitting portion 66 having a smaller diameter than the mounting base portion 65 is formed on the outer peripheral portion of the piston body 41 on the valve disk 42 side in the axial direction from the mounting base portion 65. The fitting portion 66 includes a cylindrical outer peripheral fitting surface 67 and an annular seal groove 68 that is recessed radially inward from the outer peripheral fitting surface 67. The fitting portion 66 is provided on the side of the inner sheet 61 and the outer sheet 62 in the axial direction of the piston body 41, and the outer peripheral fitting surface 67 is provided on the outer peripheral side of the radially outer sheet 62 of the piston body 41. ing. In the plurality of passages 51, the opening on the side opposite to the valve disk 40 is located radially outside the opening on the valve disk 40 side, and the mounting base portion 65 is located radially outside the outer seat 62. And a position between the fitting portion 66.

  The piston 16 further includes a piston body 71 (second valve main body), a guide disk 72 formed by laminating a plurality of single disks, and a plurality of single disks in order from the axial step 33 side in the axial direction. A valve disk 73 (second disk) configured by stacking, a support disk 74 configured by stacking a plurality of single disks, and a contact disk 75 configured by stacking a plurality of single disks, And a regulating member 76. The piston body 71, the guide disk 72, the valve disk 73, the support disk 74, the contact disk 75, and the restriction member 76 are all made of metal. Each of the regulating members 76 is thicker than a single disk constituting the guide disk 72 made of a thin plate, a single disk constituting the valve disk 73, a single disk constituting the support disk 74, and a single disk constituting the contact disk 75. Is thick and highly rigid.

  Further, the piston 16 has a rubber seal member 77 interposed between the piston body 41 and the piston body 71.

  The piston body 71 has a bottomed cylindrical shape having a cylindrical cylindrical portion 81 and a bottom portion 82 provided on the radially inner side of one axial end of the cylindrical portion 81. The bottom portion 82 is provided so as to expand in the direction perpendicular to the axis of the cylindrical portion 81. Between the cylinder part 81 and the bottom part 82, an R chamfer 83 is provided at the inner corner position. The R chamfer 83 has a smaller diameter toward the bottom portion 82 side, and smoothly connects the tubular portion 81 and the bottom portion 82.

  In the piston body 71, a fitting hole 85 for fitting the mounting shaft portion 32 of the piston rod 21 is formed in the center of the bottom portion 82 which is the center in the radial direction so as to penetrate in the axial direction. In addition, a plurality of passages 86 are formed on the bottom portion 82 on the side of the tubular portion 81 in the axial direction so as to penetrate the inside of the bottom portion 82 in the axial direction outside the radial fitting hole 85 and inside the R chamfer 83. Has been. The plurality of passages 86 are formed in the bottom portion 82 at equal intervals in the circumferential direction. The plurality of passages 86 are provided with a tapered portion 87 whose diameter increases toward the cylindrical portion 81 side at the opening position on the axial cylindrical portion 81 side on the piston body 41 side, and is opposite to the axial cylindrical portion 81. The side is a constant inner diameter portion 88 having a constant inner diameter regardless of the axial position. An annular passage 91 having an annular shape is formed on the entire bottom surface of the piston body 71 on the side opposite to the cylindrical portion 81 in the axial direction so as to communicate the plurality of passages 86.

  By forming the annular passage 91, an annular inner sheet 92 inside the annular passage 91 in the radial direction of the piston body 71 is formed at the end of the piston body 71 opposite to the piston body 41 in the axial direction. An annular outer sheet 93 (second sheet) outside the annular passage 91 is formed so as to protrude in the axial direction of the piston body 71. In other words, on the opposite side of the piston body 71 from the piston body 41, an annular outer sheet 93 and an annular inner sheet 92 radially inward of the outer sheet 93 project in the axial direction.

  The piston body 71 is provided with a tapered portion 95 having a smaller diameter at the outer peripheral portion opposite to the bottom portion 82 of the cylindrical portion 81, and the outer peripheral portion of the bottom portion 82 is separated from the cylindrical portion 81. A tapered portion 96 having a small diameter is provided. In the piston body 71, the bottom portion 82 abuts against and regulates a predetermined deformation or more when the valve disk 42 is separated from the outer seat 62.

  In the guide disk 72, any single disk constituting the guide disk 72 has an annular shape, and the mounting shaft portion 32 is fitted to the inner peripheral side. In the guide disk 72, a plurality of notches 101 are formed in the outer peripheral portion at intervals in the circumferential direction. The maximum outer diameter of the guide disk 72 is larger than the outer diameter of the end face of the inner seat 92 on the guide disk 72 side, and smaller than the inner diameter of the end face of the outer seat 93 on the valve disk 73 side. In the support disk 74, any single disk constituting the support disk 74 has an annular shape, and the mounting shaft portion 32 is fitted to the inner peripheral side. The support disk 74 has an outer diameter larger than the maximum outer diameter of the guide disk 72.

  In the contact disk 75, all the single disks constituting the contact disk 75 have an annular shape, and the mounting shaft portion 32 is fitted to the inner peripheral side. The contact disk 75 has an outer diameter larger than the outer diameter of the support disk 74. The restricting member 76 has an annular shape, and the mounting shaft portion 32 is fitted to the inner peripheral side, and the outer diameter is larger than the outer diameter of the support disk 74 and smaller than the outer diameter of the contact disk 75. It has become.

  In the valve disk 73, each of the single disks constituting the valve disk 73 has an annular shape. The valve disk 73 has an inner diameter slightly larger than the maximum outer diameter of the guide disk 72 and smaller than the outer diameter of the support disk 74, and the outer diameter of the valve disk 73 is the outer sheet 93 of the piston body 71. The diameter is substantially the same as the outer diameter of the end face on the valve disc 73 side. The valve disc 73 is detachably mounted on the outer seat 93 and is mounted on the support disc 74 so as to be seated. The abutting disc 75 abuts against and regulates a predetermined deformation or more when the valve disc 73 is separated from the outer seat 93.

  When the piston 16 is assembled to the piston rod 21, the regulating member 37, the contact disk 38, the small-diameter disk 39, and the valve disk 40 are inserted into the piston rod 21 with the attachment shaft portions 32 inserted inside thereof. The piston body 41 provided with the sliding contact member 44 and the seal member 77, the valve disk 42, the small diameter disk 43, the piston body 71, and the guide disk 72 are stacked on the shaft step portion 33 in this order. . At that time, the cylinder portion 81 of the piston body 71 is fitted into the fitting portion 66 of the piston body 41 in a state where the seal member 77 is previously disposed in the seal groove 68.

  Further, the valve disk 73 is overlaid on the outer sheet 93 of the piston body 71 with the guide disk 72 inserted inside. Further, the support disk 74, the contact disk 75, and the regulating member 76 are overlaid on the guide disk 72 and the valve disk 73 in this order in a state where the attachment shaft portions 32 are inserted into the respective insides.

  With the components arranged in this manner, the nut 35 is screwed onto the male screw 34 of the mounting shaft portion 32 that protrudes beyond the regulating member 76. Thereby, the regulating member 37, the contact disk 38, the small diameter disk 39, the valve disk 40, the piston body 41 provided with the sliding contact member 44 and the seal member 77, the valve disk 42, and the small diameter disk 43 The piston body 71, the guide disk 72, the support disk 74, the abutting disk 75, and the regulating member 76 are respectively sandwiched between the shaft step portion 33 of the piston rod 21 and the nut 35 on the inner peripheral side. And is clamped in the axial direction. At that time, the valve disc 73 is not clamped in the axial direction. The nut 35 is a general-purpose hex nut.

  In the piston 16 attached to the piston rod 21 in this way, the minimum axial distance between the support disk 74 and the outer seat 93 is shorter than the axial thickness of the valve disk 73. When there is no pressure difference between the annular passage 91 side and the lower chamber 18 side, the valve disc 73 abuts the support disc 74 on the inner circumference side with the set load and the outer seat on the outer circumference side with the set load. 93 abuts. Thereby, the communication between the annular passage 91 and the lower chamber 18 is blocked.

  When the pressure in the annular passage 91 exceeds the set load and becomes higher than the pressure in the lower chamber 18 from this state, the valve disc 73 bends with the outer peripheral corner of the support disc 74 on the valve disc 73 side as a fulcrum and the outer peripheral side is outside It leaves | separates from the sheet | seat 93 and the annular channel | path 91 and the lower chamber 18 are connected. At this time, the valve disk 73 is a guide disk in which a plurality of notches 101 are intermittently formed in the circumferential direction while the inner circumferential side is in contact with the outer circumferential corner of the support disk 74 over the entire circumference. It moves to the direction away from the support disk 74, being guided by the outer periphery of 72 and suppressing radial movement.

  Thus, the valve disc 73 has a simple support structure in which the inner peripheral side is supported by the support disc 74 only on one side without being clamped from both sides.

  The piston 16 attached to the piston rod 21 includes a fitting portion 66 having a cylindrical outer peripheral fitting surface 67 on the outer peripheral side of the outer sheet 62 of the piston body 41, and a cylindrical inner periphery of the piston body 71. A cylindrical portion 81 having a fitting surface 107 is fitted through a seal member 77. At this time, the outer peripheral fitting surface 67 of the fitting portion 66 and the inner peripheral fitting surface 107 of the cylindrical portion 81 are opposed to each other in the radial direction with the axial position overlapped, and the seal groove 68 of the fitting portion 66 is The inner peripheral fitting surface 107 of the cylindrical portion 81 crosses the entire length in the axial direction in the axial direction.

  Here, the inner diameter of the inner peripheral fitting surface 107 of the cylindrical portion 81 is larger than the outer diameter of the outer peripheral fitting surface 67 of the fitting portion 66, so that there is a gap between the cylindrical portion 81 and the fitting portion 66 in the radial direction. Can be fitted. Further, the inner diameter of the inner peripheral fitting surface 107 is smaller than the outer diameter of the seal member 77 disposed in the seal groove 68 before being fitted to the cylindrical portion 81, and thus is disposed in the seal groove 68. The seal member 77 is fitted into the cylindrical portion 81 with the outer diameter reduced. Thereby, the fitting part 66 and the cylinder part 81 are liquid-tightly fitted via the seal member 77. As a result, the internal intermediate passage 108 between the piston body 41 and the piston body 71 communicates with the lower chamber 18 through a gap for fitting between the fitting portion 66 and the cylindrical portion 81. regulate.

  Further, the piston 16 attached to the piston rod 21 has a cylindrical portion 81 of the piston body 71 that is spaced apart from the mounting base portion 65 of the piston body 41 in the axial direction, and a tapered portion 95 of the cylindrical portion 81 is It faces the direction of the plurality of passages 51.

  The plurality of passages 51 of the piston body 41 are opened such that the upper chamber 17 side in the axial direction of the piston body 41 is radially inward and the lower chamber 18 side in the axial direction is radially outward. An annular passage 53 is formed so as to connect the upper chamber 17 side of these passages 51. A damping force generating mechanism 111 includes an inner seat 56 and an outer seat 57 on both sides in the radial direction of the annular passage 53 and a valve disk 40 placed so as to be seated on the inner seat 56 and the outer seat 57 so as to close the annular passage 53. Is configured. The damping force generation mechanism 111 is disposed on the upper chamber 17 side, which is one end side of the piston body 41 in the axial direction, and is attached to the piston rod 21.

  The damping force generation mechanism 111 maintains a closed state with respect to the flow of oil from the upper chamber 17 to the lower chamber 18 via the annular passage 53 and the plurality of passages 51, while the plurality of passages 51 from the lower chamber 18. And the flow of the oil liquid to the upper chamber 17 side through the annular passage 53, and therefore, the plurality of passages 51 and the annular passage 53 are used when the piston rod 21 and the piston 16 move to the contraction side. It is a contraction-side passage through which the oil passes. That is, the plurality of passages 51 and the annular passage 53 serve as a contraction side passage 117 from which the oil liquid flows from the lower chamber 18 toward the upper chamber 17 by the movement of the piston 16 in the contraction stroke. The compression side passage 117 penetrates the inside of the piston body 41 in the axial direction. The damping force generation mechanism 111 provided for the contraction side passage 117 is a contraction side damping force generation mechanism that generates a damping force by suppressing the flow of oil in the contraction side passage 117.

  The plurality of passages 52 of the piston body 41 are open at the upper chamber 17 side in the axial direction of the piston body 41 on the radially outer side and on the intermediate passage 108 side in the axial direction on the radially inner side, respectively. An annular passage 54 is formed so as to connect the intermediate passage 108 side of these passages 52. Further, the plurality of passages 86 of the piston body 71 are opened in the intermediate passage 108, and the annular passage 91 connecting the plurality of passages 86 of the piston body 71 is disposed on the lower chamber 18 side.

  An inner seat 61 and an outer seat 62 on both sides in the radial direction of the annular passage 54 and a valve disc 42 mounted so as to be seated on the inner seat 61 and the outer seat 62 so as to close the annular passage 54 constitute a damping valve 113. The piston body 41 including the inner seat 61 and the outer seat 62 is a main body portion of the damping valve 113. The damping valve 113 is disposed on the intermediate passage 108 side, which is the other end side in the axial direction of the piston body 41, and is attached to the piston rod 21.

  An inner seat 92 and an outer seat 93 on both sides in the radial direction of the annular passage 91 and a valve disk 73 placed so as to be seated on the inner seat 92 and the outer seat 93 so as to close the annular passage 91 constitute a damping valve 114. The piston body 71 including the inner seat 92 and the outer seat 93 is a main body portion of the damping valve 114. The damping valve 114 is disposed on the lower chamber 18 side opposite to the piston body 41 in the axial direction of the piston body 71 and is attached to the piston rod 21.

  The damping valve 113 and the damping valve 114 constitute a damping force generating mechanism 115.

  The damping valve 113 of the damping force generating mechanism 115 maintains a closed state with respect to the flow of the oil liquid from the intermediate passage 108 to the upper chamber 17 side via the annular passage 54 and the plurality of passages 52, while from the upper chamber 17. It opens with respect to the flow of the oil to the intermediate passage 108 side via the plurality of passages 52 and the annular passage 54. The damping valve 114 opens with respect to the flow of oil from the intermediate passage 108 to the lower chamber 18 via the plurality of passages 86 and the annular passage 91. Therefore, the plurality of passages 52, the annular passage 54, the intermediate passage 108, the plurality of passages 86, and the annular passage 91 become an extension side passage through which the oil liquid passes when the piston rod 21 and the piston 16 move to the extension side. ing. In other words, the plurality of passages 52, the annular passage 54, the intermediate passage 108, the plurality of passages 86, and the annular passage 91 are extended so that the oil liquid flows from the upper chamber 17 toward the lower chamber 18 by the movement of the piston 16 during the extension stroke. A side passage 118 (passage) is formed. The extension side passage 118 passes through the inside of the piston bodies 41 and 71 in the axial direction. The damping force generation mechanism 115 provided for the extension side passage 118 is an extension side damping force generation mechanism that generates a damping force by suppressing the flow of the oil liquid in the extension side passage 118.

  The plurality of contraction-side passages 117 and the extension-side passages 118 are all passages through which oil, which is a working fluid, flows by sliding within the inner cylinder 3 of the piston 16, and these contraction-side passages 117 and extension-side passages 118. A damping force generation mechanism 115 that suppresses the flow of the oil liquid in the extension side passage 118 and generates a damping force is provided in the extension side passage 118 that is a part of the extension side passage 118. The piston body 41 is formed with a plurality of passages 51 and an annular passage 53 that are part of the extension side passage 118 in the axial direction. The piston body 71 has a part of the extension side passage 118. A plurality of passages 86 and an annular passage 91 are formed so as to penetrate the inside in the axial direction. A damping valve 113 and a damping valve 114 are provided in series in the extension side passage 118 through which the oil in the upper chamber 17 flows toward the lower chamber 18.

  As shown in FIG. 1, the above-described 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 131 that partitions the lower chamber 18 and the reservoir chamber 6, a damping valve 132 provided on the lower side of the base valve member 131, that is, the reservoir chamber 6 side, and an upper side of the base valve member 131. That is, it has a suction valve 133 provided on the lower chamber 18 side and a mounting pin 134 for attaching the damping valve 132 and the suction valve 133 to the base valve member 131.

  The base valve member 131 has an annular shape, and a mounting pin 134 is fitted on the inner peripheral side. The base valve member 131 includes a plurality of passages 135 through which oil is circulated between the lower chamber 18 and the reservoir chamber 6 and between the lower chamber 18 and the reservoir chamber 6 outside the passage 135 in the radial direction. And a plurality of passages 136 through which the oil liquid is circulated. The damping valve 132 on the reservoir chamber 6 side allows the flow of oil from the lower chamber 18 to the reservoir chamber 6 through the passage 135, while allowing the flow of oil from the reservoir chamber 6 to the lower chamber 18 through the passage 135. Suppress. The suction valve 133 allows the flow of oil from the reservoir chamber 6 to the lower chamber 18 via the passage 136, while suppressing the flow of oil from the lower chamber 18 to the reservoir chamber 6 through the passage 136.

  The damping valve 132 opens in the contraction stroke of the shock absorber 1 to flow the oil from the lower chamber 18 to the reservoir chamber 6 and generate a damping force. The suction valve 133 is opened during the expansion stroke of the shock absorber 1 to flow oil from the reservoir chamber 6 into the lower chamber 18. The suction valve 133 allows the liquid to flow from the reservoir chamber 6 to the lower chamber 18 without substantially generating a damping force so as to compensate for the shortage of the liquid mainly caused by the extension of the piston rod 21 from the inner cylinder 3. Fulfills the function.

  In the shock absorber 1 of the first embodiment, in the expansion stroke, the pressure of the upper chamber 17 is increased and the pressure of the lower chamber 18 is decreased due to the movement of the piston 16, and the oil in the upper chamber 17 passes through the expansion side passage 118. Through the lower chamber 18 side. When the piston speed, which is the moving speed of the piston 16, is extremely low, the oil liquid in the upper chamber 17 moves from the plurality of passages 52 constituting the extension side passage 118 and the annular passage 54 to the valve disc 42 constituting the damping valve 113. While being in contact with the outer seat 62, it flows through the fixed orifice 63 formed in the valve disk 42, and flows through the intermediate passage 108, the plurality of passages 86 and the annular passage 91 that constitute the extension side passage 118, and thereby the damping valve. The valve disc 73 constituting 114 flows into the lower chamber 18 through a gap between the valve disc 73 and the outer seat 93 while being separated from the outer seat 93. As a result, the valve disc 73 and the outer seat 93 of the damping valve 114 suppress the flow of the oil liquid in the extension side passage 118 and generate a damping force of the valve characteristic. At this time, the valve disc 73 bends with the outer peripheral corner portion of the support disc 74 on the valve disc 73 side as a fulcrum, and the outer peripheral side is separated from the outer sheet 93. The inner peripheral edge portion is guided by the outer peripheral portion of the guide disk 72 and is moved away from the support disk 74 while the radial movement is suppressed.

  Further, when the piston speed becomes faster than the above, the oil in the upper chamber 17 is separated from the valve disc 42 while the valve disc 42 constituting the damping valve 113 is separated from the outer seat 62 from the plurality of passages 52 and the annular passage 54. The valve disc 73 constituting the damping valve 114 is separated from the outer seat 93 via the intermediate passage 108, the plurality of passages 86, and the annular passage 91, while passing through the gap with the outer seat 62. It flows into the lower chamber 18 through a gap between the disk 73 and the outer sheet 93. Accordingly, the valve disc 42 and the outer seat 62 of the damping valve 113 and the valve disc 73 and the outer seat 93 of the damping valve 114 suppress the flow of the oil liquid in the expansion side passage 118 to generate a damping force of the valve characteristic. .

  In the contraction stroke, the pressure of the lower chamber 18 increases and the pressure of the upper chamber 17 decreases due to the movement of the piston 16, and the oil in the lower chamber 18 flows to the upper chamber 17 side via the contraction side passage 117. When the piston speed is low, the oil in the lower chamber 18 is formed on the valve disc 40 while the valve disc 40 constituting the damping force generation mechanism 111 is in contact with the outer seat 57 from the compression side passage 117. The fixed orifice 58 of the damping force generation mechanism 111 suppresses the flow of the oil liquid in the contraction side passage 117 and generates a damping force having an orifice characteristic. Further, when the piston speed increases, the oil introduced from the lower chamber 18 into the contraction side passage 117 flows between the valve disk 40 and the outer seat 57 while opening the valve disk 40 and is attenuated. The valve disc 40 and the outer seat 57 of the force generation mechanism 111 suppress the flow of the oil liquid in the contraction side passage 117 and generate a damping force of the valve characteristic.

  Patent Document 1 described above describes a shock absorber in which a piston body is composed of two parts in order to provide a first valve and a second valve in series along a flow path of a working fluid in the piston body. In this shock absorber, since it is necessary to regulate the leakage of the working fluid from the joining part of the two parts, it is necessary to press-fit the other part into one part so that no gap is generated. However, the press-fitting may cause distortion in the parts, and the damping force characteristics may become unstable due to deformation of the seat portions of the first valve and the second valve.

  On the other hand, the shock absorber 1 of the first embodiment is used when the piston 16 is fastened to the piston rod 21 with an axial force by the shaft step portion 33 of the piston rod 21 and the nut 35 screwed to the piston rod 21. Since the fitting portion 66 on the outer peripheral side of the outer sheet 62 of the piston body 41 and the cylinder portion 81 of the piston body 71 are fitted via the seal member 77, the piston body 41 and the piston body 71 are press-fitted. Without any gaps. Therefore, it is possible to suppress distortion generated in the inner sheets 56 and 61 and the outer sheets 57 and 62 projecting from the piston body 41 and the inner sheet 92 and the outer sheet 93 projecting from the piston body 71. As a result, the valve disc 40 can be stably seated on the inner seat 56 and the outer seat 57 of the piston body 41, and the valve disc 42 can be seated stably on the inner seat 61 and the outer seat 62 of the piston body 41. The valve disc 73 can be stably seated on the outer seat 93 of the piston body 71. Therefore, the damping force characteristic can be stabilized.

  Moreover, if there is a press-fit portion, the fastening axial force may be lost by the press-fit portion when the piston 16 is fastened by the shaft step portion 33 of the piston rod 21 and the nut 35, but such a situation is eliminated. The piston 16 can be fastened to the piston rod 21 with a prescribed fastening axial force.

  Further, a tapered portion 95 having a smaller diameter as it is farther from the bottom portion 82 is provided on the outer peripheral portion of the piston body 71 opposite to the bottom portion 82, and this tapered portion 95 faces the direction of the plurality of passages 51. Therefore, it is possible to mitigate sudden pressure fluctuations when the oil liquid flows into the plurality of passages 51 from the radially outer side of the piston body 71 during the contraction stroke. Therefore, the generation of abnormal noise can be suppressed.

  Moreover, since the taper part 87 is provided in the piston body 41 side of the some channel | path 86 which penetrates the inside of the piston body 71, ie, the upstream of the flow of an oil liquid, the pressure loss which arises in the some channel | path 86 is suppressed. Can do. Therefore, the responsiveness is improved.

  Further, since the R chamfer 83 is provided at the inner angle position between the cylinder portion 81 and the bottom portion 82 of the piston body 71, pressure loss generated in the intermediate passage 108 between the piston body 71 and the piston body 41 is suppressed. be able to. Therefore, the responsiveness is improved.

  Here, in the first embodiment, contrary to the above, an annular seal groove that is recessed radially outward from the inner peripheral fitting surface 107 is formed in the cylindrical portion 81 of the piston body 71, and a seal member is formed in the seal groove. May be arranged, and the fitting portion 66 without the seal groove of the piston body 41 may be fitted thereto.

“Second Embodiment”
Next, the second embodiment will be described mainly on the basis of FIG. 3 with a focus on differences from the first embodiment. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

  As shown in FIG. 3, in the second embodiment, the piston 16A is partially different from the piston 16 of the first embodiment. The piston 16 </ b> A has a metal piston body 41 </ b> A and a piston body 41 </ b> B (first valve main body), each of which has a shape obtained by substantially dividing the piston body 41 of the first embodiment into two parts. That is, the piston 16A has a piston body 41A, a piston body 41B, and a piston body 71 similar to that of the first embodiment.

  The piston 16A has the same restricting member 37, contact disk 38, small-diameter disk 39 and valve disk 40 as in the first embodiment. The piston body 41A is superimposed on the valve disk 40, and the piston body 41A A piston body 41 </ b> B is superimposed on the side opposite to the valve disk 40.

  The piston body 41A is formed in an annular shape at the center in the radial direction so that a fitting hole 50A for fitting the mounting shaft portion 32 of the piston rod 21 penetrates in the axial direction. Further, the piston body 41A has a bent passage 51A extending in the axial direction outside the radial fitting hole 50A, and extending in the axial direction outside the radial fitting hole 50A. A bent-shaped passage 52A is formed. Although only one location is shown in FIG. 3 because of the cross-section, the passage 51A and the passage 52A are both formed in the piston body 41A in the circumferential direction and are alternately arranged in the circumferential direction of the piston body 41A. Has been.

  Further, the piston body 41A has an annular passage 53 similar to that of the first embodiment in which a plurality of passages 51A are communicated with an end portion on the valve disc 40 side in the axial direction, an inner seat 56 on the radially inner side, and an annular shape. An outer sheet 57 radially outside the passage 53 is formed. In the plurality of passages 52 </ b> A, the opening on the valve disk 40 side is located on the radially outer side than the opening on the side opposite to the valve disk 40, and is opened on the radially outer side than the outer seat 57.

  The piston body 41A is formed with an annular passage 54A having an annular shape over the entire circumference of the piston body 41A so as to connect the plurality of passages 52A at the end opposite to the axial valve disc 40. By forming the annular passage 54A, an inner contact portion 61A on the inner side of the annular passage 54A in the radial direction of the piston body 41A is formed at the end of the piston body 41A opposite to the valve disc 40 in the axial direction. Both outer contact portions 62A outside the annular passage 54A are provided so as to protrude in the axial direction of the piston body 41A. In the plurality of passages 51A, the opening on the side opposite to the valve disc 40 is located radially outside the opening on the valve disc 40 side, and is opened radially outside the outer contact portion 62A. Yes.

  The piston body 41A is formed by sintering and has the same shape on both sides with respect to the center in the axial direction, so that there is no distinction between the front and the back. That is, it can be attached to the piston rod 21 in any axial direction.

  The piston body 41B is formed in an annular shape so that a fitting hole 50B for fitting the mounting shaft portion 32 of the piston rod 21 penetrates in the axial direction at the center in the radial direction. The piston body 41B is formed with a plurality of passages 51B extending in the axial direction outside the radial fitting holes 50B at equal intervals in the circumferential direction.

  The piston body 41B is formed with an annular passage 53B that forms a ring over the entire circumference of the piston body 41B so as to connect the plurality of passages 51B at the end of the piston body 41A in the axial direction. By forming the annular passage 53B, the inner abutting portion 56B and the annular passage 53B inside the annular passage 53B in the radial direction of the piston body 41B are provided at the end of the piston body 41B on the piston body 41A side in the axial direction. An outer abutting portion 57B is provided on the outer side.

  The piston body 41B has an annular passage 54 similar to that of the first embodiment in which a plurality of passages 51B are communicated with an end portion on the opposite side to the axial piston body 41A, and an inner sheet 61 on the radially inner side thereof. And the outer sheet | seat 62 of the radial direction outer side of the annular channel | path 54 is formed.

  The piston body 41A has a mounting base portion 65 similar to that of the first embodiment in which the sliding contact member 44 is mounted on the outer peripheral portion thereof, and the piston body 41B has an outer peripheral fitting on the outer peripheral portion thereof. A fitting portion 66 similar to that of the first embodiment having the surface 67 and a seal groove 68 that is recessed radially inward from the outer peripheral fitting surface 67 is formed. As for the fitting part 66, the outer periphery fitting surface 67 is provided in the outer peripheral side rather than the outer sheet | seat 62 in the radial direction of piston body 41B. A seal member 77 similar to that of the first embodiment is disposed in the seal groove 68 of the fitting portion 66.

  The piston 16A has the same valve disc 42, small diameter disc 43, piston body 71, guide disc 72, valve disc 73, support disc 74, contact disc 75, and restricting member 76 as in the first embodiment. .

  When the piston 16A is assembled to the piston rod 21, the regulating member 37, the contact disk 38, the small-diameter disk 39, and the valve disk 40 are inserted into the piston rod 21 with the mounting shaft portions 32 inserted into the piston rods 21 respectively. The piston body 41A provided with the sliding contact member 44, the piston body 41B provided with the seal member 77, the valve disk 42, the small diameter disk 43, the piston body 71, and the guide disk 72 in this order. The shaft step 33 is overlaid. At that time, the piston body 41A and the piston body 41B abut the inner abutting portion 61A and the inner abutting portion 56B over the entire circumference, and contact the outer abutting portion 62A and the outer abutting portion 57B over the entire circumference. Will be in contact. In this state, the annular passage 54A and the annular passage 53B communicate with each other. In this state, the cylinder portion 81 of the piston body 71 is fitted into the fitting portion 66 of the piston body 41B in a state where the seal member 77 is previously disposed in the seal groove 68.

  Further, the valve disk 73 is overlaid on the outer sheet 93 of the piston body 71 with the guide disk 72 inserted inside. Further, the support disk 74, the contact disk 75, and the regulating member 76 are overlaid on the guide disk 72 and the valve disk 73 in this order in a state where the mounting shaft portion 32 is inserted inside each of them.

  With the components arranged in this manner, the nut 35 is screwed onto the male screw 34 of the mounting shaft portion 32 that protrudes beyond the regulating member 76. Accordingly, the regulating member 37, the contact disk 38, the small diameter disk 39, the valve disk 40, the piston body 41A provided with the sliding contact member 44, the piston body 41B provided with the seal member 77, and the valve The disk 42, the small-diameter disk 43, the piston body 71, the guide disk 72, the support disk 74, the contact disk 75, and the regulating member 76 are each the inner peripheral side or the shaft step portion of the piston rod 21. 33 and the nut 35 to be clamped in the axial direction. At that time, the valve disc 73 is not clamped in the axial direction.

  By being clamped in the axial direction in this way, the piston body 41A and the piston body 41B have the inner contact portion 61A and the inner contact portion 56B in close contact with each other without any gap, and the outer contact portion 62A and the outer contact portion 62B. The contact portion 57B is in close contact with the entire circumference without any gap. In other words, the space between the inner contact portion 61A and the inner contact portion 56B is sealed over the entire periphery, and the space between the outer contact portion 62A and the outer contact portion 57B is sealed over the entire periphery. That is, the leakage of the oil from the annular passages 54A and 53B of the piston body 41A and the piston body 41B is restricted.

  In the piston 16 </ b> A attached to the piston rod 21 in this way, the fitting portion 66 and the cylindrical portion 81 are fluid-tightly fitted via the seal member 77, and the fitting portion 66 and the cylindrical portion 81 are fitted. The intermediate passage 108 between the piston body 41 </ b> B and the piston body 71 is restricted from communicating with the lower chamber 18 through the gap. Moreover, the taper part 95 of the cylinder part 81 of the piston body 71 faces the direction of the plurality of passages 51A of the piston body 41A.

  The plurality of passages 51A and the annular passage 53 of the piston body 41A serve as a compression-side passage 117A through which the oil liquid passes when the piston rod 21 and the piston 16 move to the contraction side. A damping force is applied to the compression-side passage 117A. A generation mechanism 111 is provided.

  When the plurality of passages 52A, the annular passage 54A, the annular passage 53B, the plurality of passages 51B, the annular passage 54, the intermediate passage 108, the plurality of passages 86, and the annular passage 91 move to the expansion side. It is an extension side passage 118A (passage) through which the oil liquid passes, and a damping force generation mechanism 115 is provided in the extension side passage 118A.

  The piston body 41A is formed with a plurality of passages 52A and an annular passage 54A that are part of the extension side passage 118A in the axial direction, and the piston body 41B has one of the extension side passages 118A. An annular passage 53B, a plurality of passages 51B, and an annular passage 54, which are parts, are formed so as to penetrate the inside thereof in the axial direction.

  Also in the second embodiment, in the extension stroke, when the piston speed is extremely low, the oil liquid in the upper chamber 17 causes the plurality of passages 52A, the annular passages 54A, the annular passages 53B, and the plurality of passages 51B constituting the extension side passage 118A. The intermediate passage 108 constituting the fixed orifice 63 and the extension side passage 118A formed in the valve disc 42 while the valve disc 42 constituting the damping valve 113 is in contact with the outer seat 62 from the annular passage 54, It flows through the plurality of passages 86 and the annular passage 91, and flows into the lower chamber 18 through a gap between the valve disc 73 and the outer seat 93 while separating the valve disc 73 constituting the damping valve 114 from the outer seat 93. As a result, the valve disc 73 and the outer seat 93 of the damping valve 114 suppress the flow of the oil liquid in the extension side passage 118A and generate a damping force of the valve characteristic.

  Further, when the piston speed becomes faster than the above, the oil liquid in the upper chamber 17 causes the valve disk constituting the damping valve 113 from the plurality of passages 52A, the annular passage 54A, the annular passage 53B, the plurality of passages 51B, and the annular passage 54. The valve 42 forms the damping valve 114 from the intermediate passage 108, the plurality of passages 86, and the annular passage 91 through the gap between the valve disc 42 and the outer seat 62 while being spaced apart from the outer seat 62. The disc 73 flows from the outer seat 93 to the lower chamber 18 through a gap between the valve disc 73 and the outer seat 93 while being separated from the outer seat 93. As a result, the valve disc 42 and the outer seat 62 of the damping valve 113 and the valve disc 73 and the outer seat 93 of the damping valve 114 suppress the flow of the oil liquid in the extension side passage 118A and generate a damping force of the valve characteristics.

  In the contraction stroke, the oil in the lower chamber 18 flows to the upper chamber 17 side through the contraction side passage 117A. When the piston speed is low, the oil in the lower chamber 18 is formed on the valve disc 40 while the valve disc 40 constituting the damping force generation mechanism 111 is in contact with the outer seat 57 from the contraction side passage 117A. The fixed orifice 58 of the damping force generating mechanism 111 suppresses the flow of the oil liquid in the contraction side passage 117A and generates the damping force of the orifice characteristic. Further, when the piston speed increases, the oil introduced from the lower chamber 18 to the contraction side passage 117A flows between the valve disk 40 and the outer seat 57 while opening the valve disk 40, and is attenuated. The valve disc 40 and the outer seat 57 of the force generation mechanism 111 suppress the flow of the oil liquid in the contraction side passage 117A and generate a damping force of the valve characteristic.

  In the second embodiment, the same effects as in the first embodiment can be obtained, and in addition, only one piston body 41B is replaced with another piston body 41B having a different cross-sectional area of the passage 51B. Thus, the damping force characteristic by the damping valve 114 can be changed, and the piston body 41A can be shared even when the damping force characteristic is changed.

  Also in the second embodiment, contrary to the above, an annular seal groove that is recessed radially outward from the inner peripheral fitting surface 107 is formed in the cylindrical portion 81 of the piston body 71, and a seal member is provided in the seal groove. They may be arranged and fitted with the fitting portion 66 without the seal groove of the piston body 41B.

  In the above embodiment, an example in which the present invention is applied to a double cylinder type hydraulic shock absorber has been shown. You may use for the monotube type hydraulic shock absorber which forms a gas chamber with a division body, and can use it for all shock absorbers. Of course, it is possible to apply the present invention to the above-described contraction-side damping force generating mechanism 111 or to apply the present invention to the above-described base valve 25. The present invention is also applicable to the case where an oil passage communicating with the inside of the cylinder 2 is provided outside the cylinder 2 and a damping force generating mechanism is provided in the oil passage. Moreover, in the said embodiment, although the hydraulic shock absorber was shown as an example, water and air can also be used as a fluid.

  In the embodiment described above, a cylinder in which a working fluid is sealed, a piston that is slidably provided in the cylinder, and that divides the cylinder into one side chamber and another side chamber, and is connected to the piston. A piston rod extending to the outside of the cylinder; a passage through which the working fluid flows by sliding of the piston; and a damping force generator that is provided in a part of the passage and suppresses the flow of the working fluid to generate a damping force The damping force generating mechanism includes a first valve body in which a part of the passage passes through the first valve body, an annular first seat projecting from the first valve body, and the first A first disk mounted on a seat so as to be seated; and a cylindrical portion and a bottom portion that are fitted to the outer peripheral side of the first seat of the first valve body, and a part of the passage passes through the inside. Bottomed cylindrical A valve main body, an annular second seat projecting from the second valve main body, and a second disk placed so as to be seated on the second seat, the first valve body including the first disc The outer peripheral side of the seat and the cylindrical portion of the second valve body are fitted via a seal member. As a result, the outer peripheral side of the first seat of the first valve body and the cylindrical portion of the second valve body are fitted via the seal member, so that the first valve body and the second valve body are not press-fitted. Can be joined without gaps. Therefore, the distortion which arises in the 1st sheet | seat protrudingly provided by the 1st valve body and the 2nd sheet | seat protrudingly provided by the 2nd valve body can be suppressed. As a result, the first disk can be stably seated on the first seat of the first valve body, and the second disk can be stably seated on the second seat of the second valve body. Therefore, the damping force characteristic can be stabilized.

  Moreover, since the taper part is provided in the outer peripheral part on the opposite side to the said bottom part of the said 2nd valve main body, along the outer peripheral part on the opposite side to the bottom part of the 2nd valve main body. Sudden pressure fluctuations of the flowing working fluid can be suppressed.

  Moreover, since the taper part is provided in the said 1st valve main body side of the said channel | path of the said 2nd valve main body, the pressure loss which arises in the channel | path which penetrates the inside of a 2nd valve main body can be suppressed.

  In addition, since an R chamfer is provided at the inner angle position between the cylindrical portion and the bottom portion of the second valve body, pressure loss generated in the passage between the first valve body and the second valve body is suppressed. can do.

1 shock absorber 2 cylinder 16 piston 17 upper chamber (one side chamber)
18 Lower room (other room)
21 Piston rod 41, 41B Piston body (first valve body)
42 Valve disc (first disc)
62 Outer sheet (first sheet)
71 Piston body (second valve body)
73 Valve disc (second disc)
77 Seal member 81 Cylindrical portion 82 Bottom portion 83 R chamfer 87 Tapered portion 95 Tapered portion 115 Damping force generating mechanism 118, 118A Extension side passage (passage)

Claims (4)

A cylinder filled with a working fluid;
A piston that is slidably provided in the cylinder and divides the cylinder into a one-side chamber and another-side chamber;
A piston rod connected to the piston and extending outside the cylinder;
A passage through which the working fluid flows by sliding of the piston;
A damping force generating mechanism that is provided in a part of the passage and suppresses the flow of the working fluid to generate a damping force;
The damping force generation mechanism is
A first valve body in which a part of the passage penetrates the interior;
An annular first seat protruding from the first valve body;
A first disk placed so as to be seated on the first seat;
A bottomed cylindrical second valve body having a cylindrical portion and a bottom portion that are fitted to the outer peripheral side of the first seat of the first valve body, and a part of the passage penetrates the inside thereof;
An annular second seat protruding from the second valve body;
A second disk placed on the second seat so as to be seatable,
The shock absorber, wherein an outer peripheral side of the first valve body from the first seat and the cylindrical portion of the second valve body are fitted via a seal member.   The shock absorber according to claim 1, wherein a taper portion is provided on an outer peripheral portion of the second valve body opposite to the bottom portion of the cylindrical portion.   The shock absorber according to claim 1 or 2, wherein a taper portion is provided on the first valve body side of the passage of the second valve body.   The shock absorber according to any one of claims 1 to 3, wherein an R chamfer is provided at an inner angle position between the cylindrical portion and the bottom portion of the second valve main body.

Images