JPWO2019044522A1 - Shock absorber - Google Patents

Abstract

A first seat (51) provided so as to surround one or more of the openings (41a) of the first passage (41) and spaced apart in the piston circumferential direction, and an opening of the second passage (42) ( 42a) is provided so as to surround the first seat (51) and is spaced inward in the piston radial direction from the first seat (51), and is lower than the first seat (51). A second seat (61), a large-diameter first disk valve (95) that is seatably mounted on the first seat (51), and a small-diameter first disk valve (95) that is seatably mounted on the second seat (61). A second disc valve (92), and the first seat (51) is such that the seat width of the outer seat portion (54) on the piston radial outer side is the seat width of the inner seat portion (55) on the piston radial inner side. Greater than width.

Description

The present invention relates to a shock absorber.
The present application claims priority based on Japanese Patent Application No. 2017-164360 filed in Japan on Aug. 29, 2017, the contents of which are incorporated herein by reference.

  There is a shock absorber capable of independently setting a valve characteristic in a low speed range and a valve characteristic in a high speed range, which is a moving speed of a piston (for example, refer to Patent Document 1). Further, there is a shock absorber in which the damping force characteristic from the low speed region to the medium speed region of the piston speed is made substantially linear by a damping valve (for example, refer to Patent Document 2).

JP-A-6-185562 JP 2000-283207 A

  In the shock absorber, an inner sheet that surrounds a passage formed inside with respect to the piston radial direction and an outer sheet that surrounds a passage formed outside is formed with a step. At this time, if the diameter of the inner seat is increased to increase the pressure receiving area of the valve seated on the inner seat, the pressure receiving area of the valve seated on the outer seat is correspondingly reduced.

  The present invention provides a shock absorber capable of suppressing a decrease in pressure receiving area of a valve seated on an outer seat.

  According to an aspect of the present invention, a shock absorber includes a cylinder in which a working fluid is sealed, a valve body provided in the cylinder, and a plurality of first passages that open to an outer peripheral side of one end surface of the valve body, A plurality of first seats provided so as to surround one or more of the openings of the first passage and spaced apart in the circumferential direction of the valve body, and an arc-shaped outer side that constitutes the first seats. The seat portion and the inner seat portion, the plurality of second passages that open to the inner peripheral side of the inner seat portion of the one end surface of the valve body, and the plurality of first seats are seatably mounted so as to be closed. A large-diameter first disc valve whose inner peripheral side is clamped and which is separated from the outer peripheral seat portion and the inner peripheral seat portion in this order when the valve is opened. The seat width of the outer seat portion is larger than the seat width of the inner seat portion.

  According to the above-mentioned shock absorber, it is possible to prevent the pressure receiving area of the valve seated on the outer seat from being reduced.

It is the front view which made a part a section which shows a shock absorber concerning one embodiment of the present invention. FIG. 4 is a sectional view taken along the line I-I of FIG. 3 showing a main part of the shock absorber according to the embodiment of the present invention. FIG. 3 is a cross-sectional view orthogonal to the axis showing the main part of the shock absorber according to the embodiment of the present invention. It is a bottom view which shows the piston main body of the shock absorber which concerns on one Embodiment of this invention. FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 4, showing the piston body of the shock absorber according to the embodiment of the present invention. It is a top view which shows the piston main body of the shock absorber which concerns on one Embodiment of this invention. FIG. 3 is a partially enlarged bottom view showing the piston body of the shock absorber according to the embodiment of the present invention. It is a characteristic diagram which shows the relationship between the piston speed and damping force of the shock absorber which concerns on one Embodiment of this invention. The horizontal axis (Vp) represents the piston speed. The vertical axis (Fd) represents the damping force.

  A shock absorber according to an embodiment of the present invention will be described below with reference to the drawings.

  The shock absorber 10 of the present embodiment is a fluid pressure shock absorber that uses a liquid or a gas as a working fluid. Specifically, it is a hydraulic shock absorber using an oil liquid as a working fluid. As shown in FIG. 1, the shock absorber 10 has a cylinder 11 in which a working fluid is enclosed. Although not shown, the cylinder 11 has a bottomed cylindrical shape with one end side (upper side in FIGS. 1 and 2) opened and the other end side (lower side in FIGS. 1 and 2) closed. A piston 12 as a valve body is slidably inserted into the cylinder 11.

  A piston rod 13 is inserted in the cylinder 11. The piston 12 is connected to one end of the piston rod 13 by a nut 14 shown in FIGS. The other end (upper side in FIGS. 1 and 2) of the piston rod 13 extends to the outside of the cylinder 11. In this way, the piston rod 13 whose one end side is connected to the piston 12 is inserted at the other end side into a rod guide and an oil seal (not shown) attached to the opening of the cylinder 11 and extends to the outside of the cylinder 11. There is. The piston 12 has a first chamber 19 inside the cylinder 11 on the bottom side (lower side in FIGS. 1 and 2) of the cylinder 11 (not shown) and an opening side (FIGS. 1 and 2) from which the piston rod 13 extends. To the second chamber 20).

  As shown in FIG. 2, the piston rod 13 has a main shaft portion 25 and a mounting shaft portion 26 at an end portion inside the cylinder 11 and having a smaller diameter than the main shaft portion 25. As a result, the main shaft portion 25 has an end surface 27 formed along the axis orthogonal direction at the end portion on the mounting shaft portion 26 side. The mounting shaft portion 26 is formed with a male screw 28 into which a female screw 30 of the nut 14 described above is screwed in a predetermined range on the side opposite to the main shaft portion 25.

  The piston 12 as a valve main body has an annular piston main body 31 and an annular belt-shaped sliding contact member 33 that is mounted on the outer peripheral surface of the piston main body 31 and is in sliding contact with the inner peripheral surface of the cylinder 11. Therefore, the piston 12 including the piston body 31 and the sliding contact member 33 has an annular shape.

  The piston body 31 is made of metal. The piston body 31 is integrally formed by sintering. The sliding contact member 33 is made of synthetic resin. The central axes of the piston main body 31 and the piston 12 integrally formed with the sliding contact member 33 are aligned. As a result, the piston body 31 and the piston 12 have the same axial direction along the central axis, the radial direction orthogonal to the central axis, and the circumferential direction around the central axis. To do. Hereinafter, the central axes of the piston body 31 and the piston 12 are referred to as the piston axis. The axial direction of the piston body 31 and the piston 12 is referred to as the piston axial direction. The radial direction of the piston body 31 and the piston 12 is referred to as the piston radial direction. The circumferential direction of the piston body 31 and the piston 12 is referred to as the piston circumferential direction.

  One end surface 31A of the piston main body 31 on the first chamber 19 side in the axial direction mainly constitutes the one end surface 12A of the piston 12 on the first chamber 19 side in the axial direction. The other end surface 31B of the piston body 31 on the second chamber 20 side in the axial direction mainly constitutes the other end surface 12B of the piston 12 on the second chamber 20 side in the axial direction.

  At the center of the piston 12 in the radial direction, that is, at the center of the piston body 31 in the radial direction, an insertion hole 35 for inserting the mounting shaft portion 26 of the piston rod 13 without a gap is formed so as to penetrate in the piston axial direction. The insertion hole 35 is formed inside the radially inner side inner peripheral portion of the piston 12.

  The piston body 31 has a first passage 41, a second passage 42, and a third passage 43 that extend linearly in the piston axial direction at positions outside the radial insertion hole 35. The first passage 41, the second passage 42, and the third passage 43 are all formed parallel to the piston axial direction.

  The first passage 41, the second passage 42, and the third passage 43, which are provided in the piston body 31, penetrate the piston 12 in the axial direction and allow the first chamber 19 and the second chamber 20 to communicate with each other. Is possible. The first passage 41 and the third passage 43 are arranged on the outer peripheral side in the radial direction of the piston body 31. The second passage 42 is arranged on the radially inner side of the piston body 31. Therefore, in the piston body 31, the second passage 42 is arranged at a position closer to the insertion hole 35 than the first passage 41 and the third passage 43.

As shown in FIG. 4, a plurality of first passages 41, second passages 42, and third passages 43 are provided in the piston body 31, respectively. The first passages 41, the second passages 42, and the third passages 43 are provided in the same number, specifically, four places each.
The first passage 41 and the third passage 43 have substantially the same distance from the piston axis. The first passages 41 and the third passages 43 are alternately arranged at equal intervals in the circumferential direction of the piston body 31. Each of the second passages 42 is aligned with the first passage 41 at a position in the circumferential direction of the piston.

  The plurality of first passages 41 have the same shape and are arranged at positions equidistant from the piston axis. The first passage 41 has an elongated hole shape in which the width in the circumferential direction of the piston is larger than the width in the radial direction of the piston. The first passage 41 is curved in an arc shape around the piston axis. As shown in FIG. 2, the first passage 41 has an opening 41a on the first chamber 19 side and an opening 41b on the second chamber 20 side. The opening 41a is open to the outer peripheral side of the one end surface 31A of the piston body 31 on the first chamber 19 side, and to the outer peripheral side of the one end surface 12A of the piston 12 on the first chamber 19 side. The opening 41b is opened on the outer peripheral side of the other end surface 31B of the piston body 31 on the second chamber 20 side, and is opened on the outer peripheral side of the other end surface 12B of the piston 12 on the second chamber 20 side. As shown in FIGS. 4 and 6, the openings 41a and 41b also have a width in the circumferential direction of the piston larger than the width in the radial direction of the piston, and are curved in an arc shape centered on the piston axis.

  The plurality of second passages 42 have the same shape and are arranged at positions equidistant from the piston axis. The second passage 42 has an elongated hole shape in which the width in the circumferential direction of the piston is larger than the width in the radial direction of the piston. The second passage 42 is curved in an arc shape centered on the piston axis. As shown in FIG. 2, the second passage 42 has an opening 42a on the first chamber 19 side and an opening 42b on the second chamber 20 side. The opening 42a is opened on the inner peripheral side of the one end surface 31A of the piston body 31, and is opened on the inner peripheral side of the one end surface 12A of the piston 12. The opening 42b is opened on the inner peripheral side of the other end surface 31B of the piston body 31, and is opened on the inner peripheral side of the other end surface 12B of the piston 12. The opening 42a is open to the inner circumference side of the piston body 31 from the opening 41a on the one end surface 31A, and the opening 42b is open to the inner circumference side of the piston body 31 from the opening 41b on the other end surface 31B. As shown in FIGS. 4 and 6, the openings 42a and 42b also have a width in the circumferential direction of the piston larger than the width in the radial direction of the piston, and are curved in an arc shape centered on the piston axis.

  The plurality of third passages 43 have the same shape and are arranged at positions equidistant from the piston axis. The third passage 43 is curved in an arc shape around the piston axis. As shown in FIG. 2, the third passage 43 has an opening 43a on the first chamber 19 side and an opening 43b on the second chamber 20 side. The opening 43a is opened on the outer peripheral side of the one end surface 31A of the piston body 31, and is opened on the outer peripheral side of the one end surface 12A of the piston 12. The opening 43b is opened on the outer peripheral side of the other end surface 31B of the piston body 31, and is opened on the outer peripheral side of the other end surface 12B of the piston 12. As shown in FIGS. 4 and 6, the openings 43a and 43b are also curved in an arc shape centered on the piston axis.

  As shown in FIG. 4, one end surface 31A of the piston body 31 is provided with a plurality of, specifically four, first sheets 51 of the same shape, which are arranged in the circumferential direction of the piston. The plurality of first sheets 51 are independently formed at positions separated from each other in the piston body 31. The plurality of first seats 51 are provided at equal intervals in the circumferential direction of the piston. The plurality of first sheets 51 are so-called irregularly shaped sheets that are not circular (annular).

  The plurality of first seats 51 are provided so as to protrude outward in the piston axial direction from an end surface portion 31a of one end surface 31A of the piston body 31 that surrounds the outer periphery of the first seat 51, as shown in FIG. . That is, the plurality of first sheets 51 are provided so as to project toward the first chamber 19 side that is the side opposite to the other end surface 31B. As shown in FIG. 4, the plurality of first sheets 51 each have a frame-shaped sheet main body 52 at the tip end on the protruding side.

  Each of the plurality of first seats 51 is provided so as to surround the opening 41a of the corresponding one of the plurality of first passages 41 on the side of the first chamber 19 with the seat main body 52 over the entire circumference. Specifically, each of the seat main body portions 52 of the plurality of first seats 51 is provided so as to surround the opening 41a of the one first passage 41 over the entire circumference. Similarly to the opening 41a, the seat body 52 in which the opening 41a of the first passage 41 is formed inside has a width in the piston circumferential direction larger than the width in the piston radial direction, and has an arc shape centered on the piston axis. It is curved.

  When the number of the first passages 41 is, for example, twice as large as that of the first sheets 51, one of the first sheets 51 is arranged so as to surround the entire opening 41a of the pair of first passages 41 in two places. That is, the first sheet 51 is provided so as to surround one or a plurality of the openings 41 a of the first passage 41, and a plurality of the first sheets 51 are arranged in the piston circumferential direction with a space therebetween.

  The third passage 43 is arranged at a central position between the first seats 51 adjacent to each other in the circumferential direction of the piston body 31.

  The seat body parts 52 of the plurality of first seats 51 each include a pair of radial seat parts 53, an outer seat part 54, and an inner seat part 55. The pair of radial seat portions 53 extends linearly in the radial direction of the piston body 31. The outer seat portion 54 extends in an arc shape in the circumferential direction of the piston body 31. The inner seat portion 55 extends in an arc shape in the circumferential direction of the piston body 31 on the piston axial center side in the radial direction of the piston body 31 with respect to the outer seat portion 54.

  The outer seat portion 54 is curved in an arc shape centered on the piston axis. The outer seat portion 54 connects the ends of the pair of radial seat portions 53 opposite to the piston axial center in the radial direction of the piston body 31. The inner seat portion 55 is curved in an arc shape centered on the piston axis. The inner seat portion 55 connects the end portions of the pair of radial seat portions 53 on the piston axial center side in the piston radial direction. In the plurality of first seats 51, all outer seat portions 54 are arranged on the same circle centered on the piston axis. All the inner seat portions 55 are also arranged on the same circle centered on the piston axis. In the seat body portions 52 of the plurality of first seats 51, the seat surfaces 52a, which are the tip surfaces on the protruding side, are flat surfaces that are orthogonal to the piston axis, as shown in FIG. The seat surfaces 52a of all the first seats 51 are arranged on the same plane.

  As shown in FIG. 7, in the first seat 51, the seat width w1 of the outer seat portion 54 on the piston radial direction outer side is larger than the seat width w2 of the inner seat portion 55 on the piston radial direction inner side in the piston radial direction. Is also big. The seat width w3 of the radial seat portion 53 in the piston circumferential direction is equal to the seat width w1 of the outer seat portion 54 in the piston radial direction, and larger than the seat width w2 of the inner seat portion 55 in the piston radial direction. The seat width w1 is the width in the piston radial direction of the seat surface portion 54a provided on the outer seat portion 54 of the seat surface 52a of the seat body portion 52. The seat width w2 is the width in the piston radial direction of the seat surface portion 55a provided on the inner seat portion 55 of the seat surface 52a. The seat width w3 is the width of the seat surface portion 53a of the seat surface 52a provided on the radial seat portion 53 in the piston circumferential direction.

  Here, showing the positional relationship between the second passage 42 and the first seat 51, the second passage 42 is arranged on the inner peripheral side of the inner seat portion 55 in the piston radial direction. That is, the plurality of openings 42a on the first chamber 19 side are arranged on the inner peripheral side of the inner seat portion 55 in the piston radial direction.

As shown in FIG. 4, on one end surface 31A of the piston body 31, a second seat 61 having an annular shape is provided on the piston axial center side in the piston radial direction with respect to the plurality of first seats 51. And are separated from each other. In the piston body 31, the second seat 61 includes an end surface portion 31a of the one end surface 31A surrounding the plurality of first seats 51 and the second seat 61 and an end surface portion 31b closer to the piston shaft than the second seat 61. As shown in, the piston is provided so as to project outward in the axial direction. That is, the second sheet 61 is provided so as to project toward the first chamber 19 side, which is the side opposite to the other end surface 31B.
In other words, the second sheet 61 is provided so as to project outward in the piston axial direction from the end surface portion 31a that surrounds the outer periphery and the end surface portion 31b that surrounds the inner periphery.

  As shown in FIG. 4, since the second seat 61 produces a damping force in the high speed region of the piston speed, and therefore the set load is applied to the first disc valve described later, the second seat 61 is different from the variant of the first seat 51. It has an annular shape centered on the piston axis. That is, the second seat 61 is separated from the first seat 51 inward in the piston radial direction over 360 ° in the piston circumferential direction. Since the first seat 51 is discontinuously arranged in the piston circumferential direction, the annular second seat 61 is a portion that overlaps the first seat 51 in the piston circumferential direction and is separated in the piston radial direction. have.

  On one end surface 31A of the piston main body 31, all the openings 42a of the second passage 42 are opened on the end surface portion 31b adjacent to the second seat 61 on the inner side in the piston radial direction. The second seat 61 is located outside the openings 42a of all the second passages 42 in the piston radial direction so as to surround the openings 42a of all the second passages 42. They are spaced apart in the radial direction. Specifically, the second sheet 61 is provided between all the first sheets 51 and the openings 42 a of all the second passages 42 so as to be partitioned between them.

  As described above, the second seat 61 is formed in an annular shape centered on the piston axis. As shown in FIG. 5, a groove 63 that is recessed in the piston axial direction is provided between each inner seat portion 55 of all the first seats 51 and the second seat 61. In other words, gaps are provided between the inner sheet portions 55 of all the first sheets 51 and the second sheets 61. The bottom surface of the groove 63 constitutes the end surface portion 31a. In the second seat 61, the seat surface 61a, which is the tip end surface on the protruding side, is a flat surface orthogonal to the piston axis.

  The second sheet 61 is provided so as to surround the opening 42 a of the second passage 42. The second seat 61 is arranged inside the first seat 51 in the piston radial direction and is spaced apart from the first seat 51 in the piston radial direction. As shown in FIG. 7, in the first seat 51, the seat width w2 in the piston radial direction of the inner seat portion 55 inside the piston radial direction is larger than the seat width w1 in the piston radial direction of the outer seat portion 54 outside the piston radial direction. Is also getting smaller. As described above, the second seat 61 can be arranged on the outer side in the radial direction of the piston by the amount that the seat width w2 of the inner seat portion 55 is reduced. In addition, the degree of freedom of the flow passage cross-sectional area of the second passage 42 is increased by increasing the flow passage cross-sectional area of the second passage 42, and the tunability is also increased.

  As shown in FIG. 5, the height of the second sheet 61 in the protruding direction is lower than the height of the first sheet 51 in the protruding direction. In other words, the protruding position of the seat surface 52a of the first seat 51 in the piston axial direction is defined as a positive direction rather than the seat surface 61a of the second seat 61 in the piston axial direction. If you do it is low. In other words, in the plurality of first seats 51 on the outer side in the radial direction of the piston body 31, the position of the seat surface 52a, which is the front end surface on the protruding side, is the front end surface of the second seat 61 on the inner side in the radial direction. It is located inward of the certain seat surface 61a in the protruding direction.

As shown in FIG. 4, the one end surface 31A of the piston body 31 has an annular central seat 66 on the piston axial center side in the piston radial direction with respect to the openings 42a of the plurality of second passages 42. It is provided separately from the opening 42a of the passage 42. In other words, the central seat 66 is provided on the inner side in the piston radial direction than the openings 42a of all the second passages 42.
The central seat 66 extends in the circumferential direction of the piston body 31 so as to surround the entire circumference of the insertion hole 35, and has an annular shape centered on the piston axis. As shown in FIG. 2, the central seat 66 is provided so as to project toward the first chamber 19 side, which is the outer side in the piston axial direction, that is, the side opposite to the other end surface 31B, than the end surface portion 31b on the outer side in the piston circumferential direction. There is. As shown in FIG. 5, the protruding end surface 66a of the central sheet 66 is a plane orthogonal to the piston axis.

  Between the second seat 61 and the central seat 66, there is an annular passage 67 that is recessed in the piston axial direction from the seat surface 61a and the front end surface 66a. As shown in FIG. 4, the annular passage 67 has an annular shape centered on the piston axis. The openings 42 a of all the second passages 42 are opened on the bottom surface of the annular passage 67.

  As shown in FIG. 5, the height of the central sheet 66 in the protruding direction is lower than the height of the second sheet 61 in the protruding direction. In other words, the protrusion position of the tip surface 66a of the central seat 66 in the piston axial direction is set to be the positive direction rather than the seat surface 61a of the second sheet 61 in the piston axial direction. If it is low. Further, in other words, the central sheet 66 is arranged such that the position of the leading end surface 66a on the protruding side is inside the position of the seat surface 61a, which is the leading end surface on the protruding side of the second sheet 61, in the protruding direction.

  As shown in FIG. 6, the other end surface 31B of the piston body 31 is provided with a plurality of, specifically, four third seats 71 of the same shape arranged in the circumferential direction of the piston. The plurality of third seats 71 are provided at equal intervals in the circumferential direction of the piston body 31. The plurality of third seats 71 are provided in the piston body 31 so as to project from the end surface portion 31c of the other end surface 31B that surrounds the outer periphery of the third seat 71 to the outside in the piston axial direction as shown in FIG. . That is, the plurality of third sheets 71 are provided so as to project toward the second chamber 20 side that is the side opposite to the one end surface 31A.

  As shown in FIG. 6, each of the plurality of third sheets 71 is provided so as to individually surround the opening 43b of the corresponding one of the plurality of third passages 43 over the entire circumference. Specifically, each of the plurality of third sheets 71 is provided so as to surround the opening 43b of the single third passage 43 over the entire circumference.

  When the number of the third passages 43 is, for example, twice that of the third seat 71, one of the third seats 71 is arranged so as to surround the entire opening 43b of the pair of the third passages 43 in two places. It An opening 41b of the first passage 41 and an opening 42b of the second passage 42 are arranged at a central position between the third seat 71 and the third seat 71 that are adjacent to each other in the circumferential direction of the piston body 31.

  Each of the plurality of third seats 71 has a pair of radial seat portions 73 extending in the piston radial direction and a circumferential seat portion 74 extending in the piston circumferential direction. The plurality of third seats 71 have a central seat portion 75, which is common to all the third seats 71, and is arranged closer to the piston axial center side in the piston radial direction than the radial seat portion 73. In the plurality of third seats 71, all the circumferential seat portions 74 are arranged on the same circle centered on the piston axis. The circumferential seat portion 74 connects the outer ends in the piston radial direction of the pair of radial seat portions 73 forming the same third seat 71. The central seat portion 75 is provided so as to surround the entire circumference of the insertion hole 35 while connecting the end portions of the radial seat portions 73 of all the third seats 71 on the piston axial center side in the piston radial direction. In all the third seats 71 including the common central seat portion 75, the seat surfaces 71a that are the front end surfaces on the protruding side are arranged on the same plane and are connected in the piston circumferential direction. The seat surfaces 71a of all the third seats 71 are one flat surface orthogonal to the piston axis.

  As shown in FIG. 2, the end surface 27 of the main shaft portion 25 of the piston rod 13 has a ring-shaped restricting member 81 and a restricting member 81, both of which are annular with the mounting shaft portion 26 inserted. Disc 82, one small-diameter disc 83, disc valve 84, piston 12, one small-diameter disc 91, disc valve 92 (second disc valve), one small-diameter disc 93, and a plurality of discs The intervening disc 94, the disc valve 95 (first disc valve), one small-diameter disc 96, one regulating disc 97, and one regulating member 98 are stacked in this order, In this state, the nut 14 is screwed to the male screw 28 protruding from the regulating member 98 of the mounting shaft portion 26 at the female screw 30. At this time, the piston 12 is attached so that the first seat 51, the second seat 61, and the central seat 66 face the nut 14 side, and the third seat 71 faces the end face 27 side.

  By fastening the nut 14 to the male screw 28, the regulating member 81, the regulating disc 82, the small-diameter disc 83, the disc valve 84, the piston 12, the small-diameter disc 91, the disc valve 92, the small-diameter disc 93, the interposed disc 94, the disc valve 95, The small-diameter disc 96, the regulation disc 97, and the regulation member 98 are all laminated in such a manner that their movement in the radial direction is regulated by the mounting shaft portion 26, and are sandwiched between the end surface 27 of the piston rod 13 and the nut 14 in this laminated state. Then, at least the inner peripheral side of these is fixed to the piston rod 13 so as not to move in the axial direction. As a result, the disc valves 84, 92, and 95 are clamped such that only the inner peripheral side thereof cannot move axially with respect to the piston rod 13.

  The regulation member 81 has an annular shape. The restricting member 81 fits the mounting shaft portion 26 on the inner peripheral side. The outer diameter of the regulating member 81 is larger than the outer diameter of the end surface 27. The regulation disc 82 has an annular shape and the mounting shaft portion 26 is fitted to the inner peripheral side. The outer diameter of the regulation disk 82 is larger than the outer diameter of the regulation member 81. The small-diameter disk 83 has an annular shape and the mounting shaft portion 26 is fitted to the inner peripheral side. The outer diameter of the small-diameter disk 83 is smaller than the outer diameter of the regulating member 81, and is substantially the same as the outer diameter of the end surface 27.

  The disc valve 84 includes, in order from the small diameter disc 83 side, one single disc 101, one single disc 102, a plurality of discs, specifically, two single discs 103 having the same outer diameter, and a plurality of discs. Specifically, it is configured by laminating two single disks 104 having the same outer diameter.

  Each of the single discs 101 to 104 has an annular shape and the mounting shaft portion 26 is fitted to the inner peripheral side. The outer diameter of the single disc 101 is smaller than the outer diameter of the regulating member 81 and larger than the outer diameter of the small disc 83. The outer diameter of the single disc 102 is larger than that of the single disc 101. The outer diameter of the single discs 103 is larger than that of the single discs 102. The outer diameter of the plurality of single discs 104 is larger than that of the single disc 103. Therefore, in the disc valve 84, the outer diameter of the single disc 101 is the smallest and the outer diameter of the plurality of single discs 104 is the largest.

  In the disc valve 84, the outer diameters of the plurality of single discs 104 having the largest diameter are larger than twice the maximum distance from the piston axis of the seat surface 71a, which is the protruding end surface of the third seats 71. It has a large diameter. Of the plurality of single discs 104, the single disc 104 arranged closest to the piston 12 contacts the seat surface 71 a of the third seat 71. The disc valve 84 closes the second chamber 20 side of the third passage 43 in a state where the unit disc 104 is in contact with the seat surface 71a of the third seat 71.

  The opening 41b of the first passage 41 on the second chamber 20 side and the opening 42b of the second passage 42 on the second chamber 20 side are not closed by the disc valve 84 and are always communicated with the second chamber 20. .

  The regulating member 81 is thicker than one of the single discs 101 to 104, and has higher rigidity than the disc valve 84 constituted by these. Further, the regulation member 81 is thicker than the regulation disc 82 and has high rigidity. When the disc valve 84 is deformed in the direction away from the third seat 71, the regulation disc 82 contacts the disc valve 84 and suppresses the deformation of the disc valve 84. The restriction member 81 restricts the deformation of the restriction disc 82 by a predetermined amount or more.

  The small-diameter disc 91 has an annular shape and the mounting shaft portion 26 is fitted to the inner peripheral side. The outer diameter of the small-diameter disk 91 is larger than the outer diameter of the front end surface 66a of the central seat 66 and smaller than twice the minimum distance from the piston axis of the seat surface 61a of the second seat 61. There is. As a result, the small-diameter disk 91 comes into contact with the front end surface 66a of the central sheet 66.

  The disc valve 92 constitutes a second disc valve. The disc valve 92 has, in order from the piston 12 side, one single disc 111 and a plurality of, specifically, two single discs 112 having the same outer diameter. That is, the second disc valve is configured by laminating one single disc 112 and a plurality of single discs 112 having the same outer diameter.

Each of the unit disks 111 and 112 has an annular shape, and the mounting shaft portion 26 is fitted to the inner peripheral side. The single disc 111 has a larger outer diameter than the small-diameter disc 91.
The outer diameter of the plurality of single discs 112 is equal to the maximum outer diameter of the single disc 111.

  The single disc 111 has a maximum outer diameter larger than the outer diameter of the seat surface 61 a of the second seat 61 and smaller than twice the minimum distance from the piston axis of the first seat 51. As a result, the single disc 111 abuts on the seat surface 61a of the second seat 61 and the front end surface 66a of the central seat 66, but does not contact the first seat 51 and the piston diameter between the unit disk 111 and the first seat 51. There is a gap in the direction. The single disc 111 is clamped on the inner side in the radial direction and always abuts on the small-diameter disc 91, while the outer side in the radial direction is seated on and away from the second seat 61. The single disc 111 closes the second passage 42 and the annular passage 67 on the side of the first chamber 19 while being seated on the second seat 61. The disc valve 92 including the unit disc 111 is provided so as to be overlapped with the disc valve 95 on the piston 12 side, and the outer periphery thereof is mounted so as to be seated on the second seat 61.

  As described above, since the seat width w2 of the inner seat portion 55 of the first seat 51 is smaller than the seat width w1 of the outer seat portion 54, the second seat 61 can be arranged outside in the piston radial direction. Accordingly, the seating position of the disc valve 92 on the second seat 61 can be arranged on the outer side in the radial direction of the piston, and as a result, the rigidity of the disc valve 92 decreases and the disc seat 92 is easily separated from the second seat 61.

  The unit disk 111 is formed with a cutout 121 on the outer peripheral side that extends across the seat surface 61a of the second seat 61 in the piston radial direction. The notch 121 is U-shaped and has a shape that extends to the outer periphery of the single disk 111. The notch 121 penetrates the single disc 111 in the plate thickness direction. A plurality of such cutouts 121 are formed in the unit disk 111 at equal intervals in the circumferential direction. The cutout portion 121 allows the inner peripheral side and the outer peripheral side of the second sheet 61 to communicate with each other even when the single disc 111 is in contact with the seat surface 61a of the second sheet 61, so that the inner peripheral side of the second seat 61 is provided. The second passage 42 and the annular passage 67 are communicated with the first chamber 19 on the outer peripheral side of the second seat 61 via the gap between the first seats 51. In other words, the cutout 121 constitutes a fixed orifice that allows the first chamber 19 and the second chamber 20 to communicate with each other by the second sheet 61 and the single disk 112 closest to the single disk 111. It should be noted that, without providing the cutout portion 121 in the single disc 111, a cutout that allows the inner peripheral side and the outer peripheral side of the second sheet 61 to communicate with each other even when the single disc 111 is in contact with the seat surface 61a of the second sheet 61. A part may be provided, and both the cutout part of the second sheet 61 and the cutout part 121 of the single disk 111 may be provided.

  The small-diameter disk 93 has an annular shape and the mounting shaft portion 26 is fitted to the inner peripheral side. The outer diameter of the small-diameter disk 93 is smaller than that of the small-diameter disk 91, and is equal to the front end surface 66a of the central sheet 66.

  The plurality of interposed disks 94 are arranged between the small-diameter disk 93 and the disk valve 95 as a small-diameter annular member. The plurality of interposed disks 94 have the same outer diameter. The plurality of interposer disks 94 have an annular shape and the mounting shaft portion 26 is fitted to the inner peripheral side. The outer diameter of the interposed disc 94 is equal to the outer diameter of the single disc 112 of the disc valve 92.

  Here, the distance between the seat surface 52a of the first seat 51 and the seat surface 61a of the second seat 61 in the piston axial direction is determined by the total thickness of the disk valve 92, the small-diameter disk 93, and the plurality of interposed disks 94. Is equivalent to. That is, according to the distance between the seat surface 52a of the first seat 51 and the seat surface 61a of the second seat 61 in the piston axial direction, the number of the plurality of interposer disks 94 is increased or decreased to obtain the seat of the first seat 51. It is possible to adjust the distance between the surface 52a and the seat surface 61a of the second seat 61 in the piston axial direction to be equal to the total thickness of the disk valve 92, the small diameter disk 93, and the plurality of interposed disks 94. it can.

  The disc valve 95 constitutes a first disc valve, and is constituted by laminating a plurality of, specifically, six single discs 125 having the same outer diameter. Each of these unit disks 125 has an annular shape and the mounting shaft portion 26 is fitted to the inner peripheral side. That is, the first disc valve is configured by laminating a plurality of single discs 125 having the same outer diameter. The outer diameters of the plurality of single discs 125 are larger than twice the maximum distance of the seat surface 52a of the first seat 51 from the piston axis. The single disk 125 closest to the disk valve 92 of the disk valve 95 abuts on the seat surface 52a and is seated on the seat body 52 of the first seat 51. In this state, the single disk 125 closes the first passage 41 on the first chamber 19 side. The single disc 125 closest to the disc valve 92 of the first seat 51 and the disc valve 95 is not formed with a cutout portion that always communicates the first passage 41 with the first chamber 19. The second seat 61 arranged on the inner peripheral side of the inner seat portion 55 is formed in an annular shape substantially concentric with the disc valve 95.

  The disc valve 95 is mounted on the first seat 51 so that it can be seated. The diameter of the disc valve 95 at the seating position on the first seat 51 is larger than the diameter of the disc valve 92 at the seating position on the second seat 61. Therefore, the disc valve 95 has lower rigidity than the disc valve 92 and is easy to open. Therefore, when the valve is opened, the outer seat portion 54 and the inner seat portion 55 are opened so as to be separated in this order. Further, as described above, since the seat width w1 of the outer seat portion 54 of the first seat 51 is made larger than the seat width w2 of the inner seat portion 55, the contact area between the disc valve 95 and the outer seat portion 54 is reduced. This can be ensured and the reduction of the pressure receiving area of the valve seated on the outer seat can be suppressed. Further, it is possible to prevent the working fluid from leaking from the space between the first seat 51 and the disc valve 95 before the disc valve 95 is opened.

  Of the outer sheet portion 54 and the inner sheet portion 55 of the first sheet 51, the inner sheet portion 55 having a low degree of contribution to the leakage suppression is the sheet width w1 of the outer sheet portion 54 having a high degree of contribution to the leakage suppression. The seat width w2 is reduced, and the second seat 61 is arranged outside the piston in the radial direction by that amount. By disposing the second seat 61 on the outer side in the piston radial direction, the seating position of the disc valve 92 on the second seat 61 is on the outer side in the piston radial direction, the rigidity of the disc valve 92 decreases, and the disc seat 92 is separated from the second seat 61. It becomes easier to sit down. Further, since the second seat 61 is arranged on the outer side in the radial direction of the piston, the flow passage cross-sectional area of the second passage 42 can be increased.

  As shown in FIG. 2, the opening 43a of the third passage 43 on the side of the first chamber 19 is not closed by the disc valves 92 and 95 and is always communicated with the first chamber 19.

  The small-diameter disk 96 has an annular shape and the mounting shaft portion 26 is fitted to the inner peripheral side. The outer diameter of the small-diameter disk 96 is slightly smaller than the outer diameter of the front end surface 66a of the central sheet 66. The regulation disc 97 has an annular shape and the mounting shaft portion 26 is fitted to the inner peripheral side. The regulation disc 97 has an outer diameter larger than that of the small-diameter disc 96. The restriction member 98 has an annular shape. The restricting member 98 fits the mounting shaft portion 26 on the inner peripheral side. The regulating member 98 has an outer diameter smaller than that of the regulating disc 97 and larger than that of the small-diameter disc 96.

  The regulating member 98 is thicker than one of the single discs 125, and has higher rigidity than the disc valve 95 composed of these. Further, the regulation member 98 is thicker than the regulation disc 97 and has high rigidity. When the disc valve 95 is deformed in the direction away from the first seat 51, the regulation disc 97 contacts the disc valve 95 and suppresses the deformation of the disc valve 95. The regulation member 98 regulates the deformation of the disc valve 95 beyond a predetermined amount.

  A plurality of first passages 41 of the piston 12, a plurality of second passages 42 and an annular passage 67, a plurality of first seats 51 of the piston 12 and an annular second seat 61, and a plurality of first seats 51 can be seated. A large-diameter disk valve 95 to be mounted and a small-diameter disk valve 92 to be seated on the second seat 61 are provided in the piston 12 to suppress the flow of the working fluid and generate a damping force. . When the piston rod 13 moves to the extension side that increases the amount of protrusion from the cylinder 11 and the piston 12 moves to the second chamber 20 side, the flow of the working fluid flowing from the second chamber 20 toward the first chamber 19 is changed. Suppress and generate a damping force on the extension side. Therefore, the plurality of first passages 41 and the plurality of second passages 42 are formed in parallel.

  A plurality of third passages 43 of the piston 12, a plurality of third seats 71 of the piston 12, and a disc valve 84 seated on these third seats 71 are provided in the piston 12 to control the flow of the working fluid and attenuate the same. Generate force. When the piston rod 13 moves to the compression side to increase the amount of entry into the cylinder 11 and the piston 12 moves to the first chamber 19 side, the flow of the working fluid flowing from the first chamber 19 to the second chamber 20 is changed. Suppress and generate damping force on the contraction side.

  In the shock absorber 10, in the extension stroke in which the piston rod 13 moves toward the extension side with respect to the cylinder 11, the pressure of the second chamber 20 is made higher than the pressure of the first chamber 19 by the piston 12 that moves together with the piston rod 13. Thereby, on the other hand, the working fluid in the second chamber 20 is introduced into the plurality of first passages 41 through the openings 41b which are always open, and acts on the disc valve 95 through the openings 41a. On the other hand, the working fluid in the second chamber 20 is introduced into the plurality of second passages 42 through the respective openings 42b which are always open, flows out from the openings 42a into the annular passage 67, and acts on the disc valve 92.

  At this time, if the piston speed, which is the moving speed of the piston 12, is extremely low, the working fluid in the plurality of first passages 41 does not cause the disc valve 95 to separate from the first seat 51, and the plurality of second passages 42 are not formed. Also, the working fluid in the annular passage 67 does not cause the disc valve 92 to separate from the second seat 61. Then, the working fluid in the second chamber 20 flows from the plurality of second passages 42 and the annular passage 67 into the first chamber 19 via the notch 121 of the single disc 111 of the disc valve 92. As a result, since the flow passage cross-sectional area becomes constant, a damping force having an orifice characteristic (the damping force is substantially proportional to the square of the piston speed) is generated.

Here, since the disc valve 95 opens and closes the plurality of first passages 41 having the openings 41a on the outer peripheral side of the one end surface 12A of the piston 12, the first valve provided so as to surround the opening 41a of the first passage 41. The seating position on the seat 51 is on the outside of the piston 12 in the radial direction of the piston. Further, the disc valve 95 has low rigidity. Therefore, the disc valve 95 is easily separated from the first seat 51. That is, the first disc valve opens before the second disc valve. Moreover, since the disc valve 95 is seated on the plurality of first seats 51, which are arranged in the circumferential direction of the piston and are spaced apart from each other, each having a short circumference, that is, a deformed seat, the pressure applied even if the flow rate is small. Is easy to rise. Therefore, the disc valve 95 is easier to open. Therefore, the disc valve 95 opens even in the low speed range where the piston speed is low (range less than v1 in FIG. 8), particularly from the very low speed range where the piston speed is low.
That is, in the low speed range where the piston speed is low, particularly from the very low speed range where the piston speed is low, the working fluid in the first passage 41 separates the disc valve 95 from the first seat 51 to open the valve. As a result, the working fluid flows from the second chamber 20 to the first chamber 19 via the plurality of first passages 41 at a flow rate according to the valve opening amount of the disc valve 95 and the plurality of first seats 51. Therefore, as shown by a portion a1 of the solid line X1 in FIG. 8, a damping force having valve characteristics (the damping force is substantially proportional to the piston speed) is generated.

  In the first sheet 51, although the seat width w2 of the inner sheet portion 55 having a low degree of contribution to leakage suppression is reduced, the sheet width w1 of the outer sheet portion 54 having a high degree of contribution to leakage suppression is set to the inner sheet portion. It is made larger than the sheet width w2 of 55. Therefore, the contact area between the disc valve 95 and the outer seat portion 54 can be secured, and the leakage of the working fluid until the disc valve 95 is opened can be suppressed.

  FIG. 8 shows a characteristic diagram showing the relationship between the piston speed and the damping force of the shock absorber according to this embodiment. In FIG. 8, the horizontal axis (Vp) represents the piston speed. The vertical axis (Fd) represents the damping force. As shown in FIG. 8, in the medium to high speed range (the range of v1 or more in FIG. 8) higher than the low speed range, the second chamber 20 to the first chamber 19, the plurality of first passages 41 to the disc valves 95, and the like. If only the working fluid flows between the plurality of first seats 51, the damping force depends on the rigidity of the disc valve 95 and remains a substantially linear characteristic, as shown by the chain double-dashed line X2 in FIG. , Rises with increasing piston speed.

  On the other hand, in the medium and high speed regions, the working fluid in the plurality of first passages 41 causes the disc valve 95 to separate from the first seat 51 to open the valve, and the plurality of second passages 42 and the annular shape. The working fluid in the passage 67 separates the disc valve 92 from the second seat 61 having a long circumferential length to open the disc valve 92. As a result, the working fluid flows from the second chamber 20 to the first chamber 19 from the plurality of first passages 41 via the disc valve 95 and the plurality of first seats 51, and at the same time, the plurality of second passages 42. And from the annular passage 67 between the disc valve 92 and one second seat 61 having a long circumferential length. At that time, the working fluid in the plurality of second passages 42 and the annular passage 67 opens the disc valve 92 by separating it from the second seat 61 at a relatively low piston speed in the medium and high speed range. A large amount of working fluid flows from the second chamber 20 to the first chamber 19 from the plurality of second passages 42 and the annular passage 67 via the disc valve 92 and the second seat 61. Therefore, as shown by the portion a2 of the solid line X1 in FIG. 8, the damping force characteristic is a saturation characteristic that suppresses the increase of the damping force with respect to the increase of the piston speed from the relatively low piston speed in the medium and high speed range. In other words, in the medium and high speed range, the damping force characteristic is a saturation characteristic that gradually increases without increasing sharply with increasing piston speed.

  At this time, as described above, by making the seat width w2 of the inner seat portion 55 of the first seat 51 smaller than the seat width w1 of the outer seat portion 54, the seating position of the disc valve 92 on the second seat 61 is set to the piston. Since the disc valve 92 can be disposed on the outer side in the radial direction, the rigidity of the disc valve 92 is reduced and the disc valve 92 is easily separated from the second seat 61. In addition, the seat width w2 of the inner seat portion 55 of the first seat 51 is made smaller than the seat width w1 of the outer seat portion 54, so that the second seat 61 can be disposed on the outer side in the piston radial direction, and the circumference of the second seat 61 can be reduced. The length is long. Further, since the second seat 61 is arranged on the outer side in the piston radial direction, the flow passage cross-sectional area of the second passage 42 can be increased. For these reasons, the working fluid in the plurality of second passages 42 and the annular passage 67 opens the disc valve 92 by separating it from the second seat 61 from the state where the piston speed is lower. Moreover, in the valve open state, the working fluid from the plurality of second passages 42 and the annular passage 67 flows more between the disc valve 92 and the second seat 61. That is, the damping force characteristic is a saturation characteristic that suppresses the increase of the damping force with respect to the increase of the piston speed.

  As described above, when the piston rod 13 moves to the extension side in the plurality of first passages 41 and the plurality of second passages 42, and the piston 12 slides in the cylinder 11 integrally with this, the working fluid is generated by this sliding. Flows from the second chamber 20 to the first chamber 19. Thereby, the flow of the working fluid is controlled to generate the damping force.

  On the other hand, in the compression stroke in which the piston rod 13 moves toward the compression side with respect to the cylinder 11, the pressure in the first chamber 19 is raised above the pressure in the second chamber 20 by the piston 12 moving together with the piston rod 13. Of the working fluid is introduced into the plurality of third passages 43 through the respective openings 43a that are always open, and acts on the disc valve 84 through the openings 43b.

  At this time, when the piston speed is low, the working fluid in the third passage 43 does not separate the disc valve 84 from the third seat 71. The working fluid in the first chamber 19 flows from the first chamber 19 to the second chamber 20 via the notch 121 of the single disc 111 of the disc valve 92, the annular passage 67 and the plurality of second passages 42. As a result, since the flow passage cross-sectional area becomes constant, a damping force having an orifice characteristic (the damping force is approximately proportional to the square of the piston speed) is generated, as shown by a portion b1 of the solid line X3 in FIG.

  In the medium-high speed range where the piston speed is higher than the low speed range, the working fluid in the third passage 43 separates the disc valve 84 from the third seat 71 to open the valve. As a result, the working fluid flows from the first chamber 19 to the second chamber 20 through the plurality of third passages 43 in a flow passage cross-sectional area corresponding to the valve opening amounts of the disc valve 84 and the plurality of third seats 71. . Therefore, as shown by the portion b2 of the solid line X3 in FIG. 8, a damping force having a valve characteristic (the damping force is substantially proportional to the piston speed) is generated.

  As described above, when the piston rod 13 moves to the contraction side in the plurality of third passages 43 and the piston 12 slides in the cylinder 11 integrally with this, the working fluid moves from the first chamber 19 to the second chamber 19 by the sliding. It flows toward the chamber 20. As a result, the flow of the working fluid is suppressed and a damping force is generated.

  The above-mentioned Patent Document 1 describes a shock absorber capable of independently setting the valve characteristic in the low speed region and the valve characteristic in the high speed region of the piston speed. Further, Patent Document 2 describes a shock absorber in which the damping force characteristic from the low speed region to the medium speed region of the piston speed is made substantially linear by a damping valve.

In the shock absorber 10 of the first embodiment, a plurality of first seats 51 are arranged on the piston 12 so as to be spaced apart from each other in the piston circumferential direction, and the first seats 51 are arranged inside the first seats 51 in the piston radial direction. And a second seat 61 that is spaced apart in the piston radial direction and is lower than the first seat 51, and further has a large-diameter disk valve 95 that can be seated on the plurality of first seats 51, A small-diameter disk valve 92 that can be seated on the seat 61 is provided.
Then, since the disc valve 95 opens and closes the plurality of first passages 41 having the openings 41a on the outer peripheral side of the one end surface 12A of the piston 12, the disc valve 95 has a seating position on the first seat 51, The outer side is in the radial direction, and the rigidity is low, and it is easy to separate from the first seat 51. Moreover, the disc valve 95 is provided so as to surround the opening 41a of the first passage 41, and is seated on a plurality of first seats 51 each having a short circumferential length and spaced apart in the piston circumferential direction. Therefore, the applied pressure is likely to rise, and the disc valve 95 is even easier to open. Therefore, the disc valve 95 opens from the low speed region where the piston speed is low, and causes the working fluid to flow from the second chamber 20 to the first chamber 19 via the plurality of first seats 51. Therefore, a substantially linear damping force is generated from the low speed region where the piston speed is low.

  Moreover, in the first seat 51, although the seat width w2 of the inner seat portion 55 on the piston radial direction inner side, which has a low degree of contribution to leakage suppression, is reduced, the outer seat portion on the piston radial direction outer side, which has a high degree of contribution to leakage suppression. The seat width w1 of 54 is larger than the seat width w2 of the inner seat portion 55. Therefore, it is possible to suppress the leakage of the working fluid in the very low speed region until the disc valve 95 opens.

  Further, in the medium to high speed range that is higher than the low speed range, the working fluid flows from the second chamber 20 to the first chamber 19 from the plurality of first passages 41 to the disk valve 95 and the plurality of first seats 51. And a plurality of second passages 42 and the annular passage 67 through the disc valve 92 and one second seat 61 having a long circumferential length. Therefore, in the medium to high speed range, the damping force characteristic is a saturation characteristic that suppresses the increase of the damping force with respect to the increase of the piston velocity from the state where the piston velocity is low.

  At this time, as described above, by making the seat width w2 of the inner seat portion 55 of the first seat 51 smaller than the seat width w1 of the outer seat portion 54, the seating position of the disc valve 92 on the second seat 61 is set to the piston. Since the disc valve 92 can be disposed on the outer side in the radial direction, the rigidity of the disc valve 92 is reduced and the disc valve 92 is easily separated from the second seat 61. Further, since the seat width w2 of the inner seat portion 55 of the first seat 51 is made smaller than the seat width w1 of the outer seat portion 54, the second seat 61 can be arranged on the outer side in the radial direction of the piston, and the circumferential length can be increased. There is. Further, since the second seat 61 is arranged on the outer side in the piston radial direction, the flow passage cross-sectional area of the second passage 42 can be increased. From these things, from the state where the piston speed is lower, the working fluid in the plurality of second passages 42 and the annular passage 67 makes the disc valve 92 separate from the second seat 61 to open the valve. In the valve open state, the working fluid from the plurality of second passages 42 and the annular passage 67 flows more between the disc valve 92 and the second seat 61. Therefore, in the medium to high speed range, the damping force characteristic becomes a saturation characteristic that suppresses the increase of the damping force with respect to the increase of the piston speed from the state where the piston speed is lower.

Further, by disposing the interposed disc 94, which is a small-diameter annular member, between the small-diameter disc 93 and the disc valve 95, the piston between the seat surface 52a of the first seat 51 and the seat surface 61a of the second seat 61. Depending on the axial distance, the number of the plurality of interposed disks 94 is increased or decreased so that the distance between the seat surface 52a of the first seat 51 and the seat surface 61a of the second seat 61 in the piston axial direction is the disk valve. It can be adjusted so as to be equal to the total thickness of 92, the small-diameter disk 93, and the plurality of interposed disks 94. With the above configuration, the number of stacked interposing discs 94 can be changed, and the number of individual discs 112 of the disc valve 92 can be increased or decreased. In this case, the damping force generated by the working fluid from the plurality of second passages 42 and the annular passage 67 flowing between the disc valve 92 and the second seat 61 is adjusted according to the disc valve 92. be able to.
That is, tunability can be secured.

  Here, making the seat width w2 of the inner seat portion 55 of the first seat 51 smaller than the seat width w1 of the outer seat portion 54 exerts a high effect particularly in the case of the shock absorber 10 in which the outer diameter of the piston 12 is small. To do. Specifically, it is particularly effective in the case of the shock absorber 10 having the piston 12 whose outer diameter is smaller than φ35 mm.

  In the above embodiments, the configuration of the present invention is applied to the side that generates the damping force on the extension side, but it may be applied to the side that generates the damping force on the contraction side. May be applied to both.

  According to the first aspect of the above-described embodiment, the shock absorber includes a cylinder in which a working fluid is sealed, a valve body provided in the cylinder, and a plurality of openings open to the outer peripheral side of one end surface of the valve body. And a plurality of first seats that are provided so as to surround one or more of the openings of the first passage and are spaced apart in the circumferential direction of the valve body, and constitute the first seat. So as to close the arc-shaped outer seat portion, the inner seat portion, the plurality of second passages that open to the inner peripheral side of the inner seat portion of the one end surface of the valve body, and the plurality of first seats. And a large-diameter first disc valve whose inner peripheral side is clamped and which is placed so that it can be seated and which is separated from the outer seat portion and the inner seat portion in this order when the valve is opened. The seat width of the outer seat portion is larger than the seat width of the inner seat portion. This can prevent the pressure receiving area of the valve seated on the outer seat from becoming small.

  According to a second aspect, in the first aspect, a second seat is formed on the inner peripheral side of the inner seat portion in an annular shape that is substantially concentric with the first disc valve and surrounds the plurality of second passages. It is characterized by having. As a result, in the medium-high speed range, the damping force characteristic has a saturation characteristic that gradually increases without increasing sharply with increasing piston speed.

  According to a third aspect, in the first or second aspect, the valve body is a piston. As a result, the movement of the piston rod controls the flow of the working fluid to generate a damping force.

  According to a fourth aspect, in any one of the first to third aspects, the second seat is formed lower than the first seat protruding with respect to the piston, and the valve body of the first disc valve is provided. It is characterized in that an annular second disc valve is provided so as to be overlapped with the side so that the outer periphery is seated on the second seat. As a result, the damping force characteristic is a saturation characteristic that suppresses the increase of the damping force with respect to the increase of the piston speed.

  According to a fifth aspect, in any one of the first to fourth aspects, the first disc valve is opened before the second disc valve. As a result, the damping force of the valve characteristic is generated even in the low speed range where the piston speed is low.

  According to a sixth aspect, in any one of the first to fifth aspects, an annular member having a smaller diameter than the second disc valve is provided between the first disc valve and the second disc valve. Is characterized by. Thereby, tunability can be secured.

  According to the above-mentioned shock absorber, it is possible to prevent the pressure receiving area of the valve seated on the outer seat from being reduced.

10 Shock Absorber 11 Cylinder 12 Piston 12A One End Surface 13 Piston Rod 19 First Chamber 20 Second Chamber 41 First Passage 41a Open 42 Second Passage 42a Open 51 First Seat 54 Outer Seat 55 55 Inner Seat 61 Second Seat 92 Disc valve (second disc valve)
95 disc valve (first disc valve)
w1, w2 sheet width

Claims (6)

A cylinder in which the working fluid is enclosed,
A valve body provided in the cylinder,
A plurality of first passages opening to the outer peripheral side of the one end surface of the valve body,
A plurality of first seats that are provided so as to surround one or more of the openings of the first passage and that are spaced apart in the circumferential direction of the valve body;
An arc-shaped outer seat portion, an inner seat portion, which constitutes the first seat,
A plurality of second passages that open to the inner peripheral side of the inner seat portion on one end surface of the valve body;
A large-diameter first disk valve that is mounted so as to be seatable so as to close the plurality of first seats, and has an annular inner peripheral side clamped so that the outer seat portion and the inner seat portion are separated in this order when the valve is opened; Has,
A shock absorber in which the seat width of the outer seat portion is larger than the seat width of the inner seat portion. The shock absorber according to claim 1, further comprising a second seat, which is formed in an annular shape substantially concentric with the first disc valve and surrounds the plurality of second passages, on the inner peripheral side of the inner seat portion. The shock absorber according to claim 1, wherein the valve body is a piston. The second seat is formed lower than the first seat projecting with respect to the piston, and is overlapped with the valve body side of the first disc valve so that the outer periphery of the second seat is annular. The shock absorber according to any one of claims 1 to 3, further comprising a disc valve. The shock absorber according to claim 1, wherein the first disc valve opens before the second disc valve. The shock absorber according to any one of claims 1 to 5, wherein an annular member having a diameter smaller than that of the second disc valve is provided between the first disc valve and the second disc valve.

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