JP2019163768A - Shock absorber - Google Patents

Abstract

To provide a shock absorber which can inhibit increase of damping force characteristics in a high speed area of a piston speed.SOLUTION: A damping force generation mechanism 100 includes: communication passages 41, 42 which are provided at a piston 12 and allow communication between one side chamber and the other side chamber; first seats 51 are provided arranged in a circumferential direction of the piston 12 on one surface of the piston 12 and respectively protrude so as to enclose inner passages 52 communicating with the communication passage 41; an annular second seat 61 which has portions spaced apart from the first seats 51 at an area closer to the radial center side of the piston 12 than the first seats 51 and protrudes with a center of the piston 12 set to its center at the outer side of an opening 42a of the communication passage 42; and a disc valve 84 seated on the first seats 51 and the second seat 61. Cutouts 97 allowing communication between the inner periphery side of the second seat 61 and the other side chamber 19 are provided between the disc valve 84 and the first seats 51 or the second seat 61.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a shock absorber.

  In some shock absorbers, a piston is provided with a plurality of valve seat portions arranged in the radial direction (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 1-288643

  In a shock absorber having a plurality of valve seats arranged in the radial direction on the piston, the working fluid flowing out from the inner periphery of the innermost valve seat passes through the valve seats toward the outer periphery. In particular, the damping force characteristic may be high particularly in the high speed region of the piston speed.

  Therefore, an object of the present invention is to provide a shock absorber that can suppress an increase in damping force characteristics in a high speed region of the piston speed.

  In order to achieve the above object, according to the present invention, there are provided a plurality of damping force generation mechanisms arranged in a piston, arranged in a circumferential direction of the piston on one surface of the piston. A first seat that protrudes so as to surround an inner passage that communicates with the communication passage, and a portion that is spaced apart from the first seat on the radial center side of the piston from the first seat. An annular second seat projecting around the center of the piston outside the opening of the communication passage, and a disc valve seated on the first seat and the second seat, the disc valve, A notch is provided between the first sheet or the second sheet to allow communication between the inner peripheral side of the second sheet and the other chamber.

  According to the present invention, an increase in damping force characteristics can be suppressed in a high speed region of the piston speed.

The principal part of the buffer of 1st Embodiment which concerns on this invention is shown, It is the fragmentary sectional view which made the piston body the cross section by the XX line shown in FIG. 2, FIG. It is the figure which looked at the piston body of the buffer of a 1st embodiment concerning the present invention from the axial direction one side. It is the figure which looked at the piston body of the buffer of a 1st embodiment concerning the present invention from the axial direction reverse side. It is a top view which shows the small diameter disc of 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 diagram which shows the damping force characteristic of 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 2nd embodiment concerning the present invention. It is a top view which shows the small diameter disc of the buffer of 2nd Embodiment which concerns on this invention. It is a fragmentary sectional view showing a buffer of a 3rd embodiment concerning the present invention. It is the figure which looked at the 2nd piston body of the buffer of a 3rd embodiment concerning the present invention from the opposite side to the 1st piston body. It is a fragmentary sectional view showing a buffer of a 4th embodiment concerning the present invention. It is the figure which looked at the 2nd piston body of the buffer of a 5th embodiment concerning the present invention from the opposite side to the 1st piston body.

“First Embodiment”
A shock absorber according to a first embodiment of the present invention will be described below with reference to FIGS.

  A shock absorber 10 according to the first embodiment shown in FIG. 1 is a fluid pressure shock absorber using a liquid or gas as a working fluid, and has a cylinder 11 in which the working fluid is sealed. Although not shown, the cylinder 11 has a bottomed cylindrical shape in which one end side (upper side in FIG. 1) is open and the other end side (lower side in FIG. 1) is closed. A piston 12 is slidably inserted into the cylinder 11.

  The other end side of the piston rod 13 whose one end side (the upper side in FIG. 1) extends to the outside of the cylinder 11 is inserted into the cylinder 11, and the piston 12 is connected to the other end portion of the piston rod 13 by a nut 14. It is connected. The piston rod 13 having the other end connected to the piston 12 in this manner is not shown in the drawing, but one end thereof is inserted into a rod guide and an oil seal attached to the opening of the cylinder 11 and extended to the outside. ing. The piston 12 includes a first chamber 19 on the bottom side (lower side in FIG. 1) of the cylinder 11 and a second chamber 20 on the side (upper side in FIG. 1) from which the piston rod 13 extends. And is defined.

  The piston rod 13 has a main shaft portion 25 and an attachment shaft portion 26 at the end in the cylinder 11 and having a diameter smaller than that of the main shaft portion 25, so that the main shaft portion 25 has a mounting shaft portion 26 side. A stepped portion 27 along the direction orthogonal to the axis is formed at the end. The attachment shaft portion 26 is formed with a male screw 28 for screwing the nut 14 into a predetermined range opposite to the main shaft portion 25.

  The piston 12 includes a substantially disc-shaped piston body 31 and an annular belt-shaped sliding contact member 33 that is attached to the outer peripheral surface of the piston body 31 and that is in sliding contact with the inner peripheral surface of the cylinder 11. The piston body 31 is integrally formed by sintering. The piston body 31 and the piston 12 on which the sliding contact member 33 is mounted have the same center axis, so that the piston body 31 and the piston 12 have the same axial direction and the same radial direction. , The circumferential direction matches.

  An insertion hole 35 through which the mounting shaft portion 26 of the piston rod 13 is inserted without a gap is formed in the center of the piston body 31 in the radial direction so as to penetrate in the axial direction. The piston body 31 has a first passage 41 (communication passage), a second passage 42 (communication passage), and a passage extending in the axial direction of the piston body 31 at positions outside the radial insertion hole 35. A third passage 43 is formed.

  The first passage 41, the second passage 42, and the third passage 43 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 at the same distance from the central axis in the radial direction of the piston body 31, and are positioned closer to the insertion hole 35 than the first passage 41 and the third passage 43. Two passages 42 are arranged. One flow passage cross-sectional area of the first passage 41 is larger than one flow passage cross-sectional area of the second passage 42 and smaller than one flow passage cross-sectional area of the third passage 43.

  As shown in FIGS. 2 and 3, a plurality of first passages 41, second passages 42, and third passages 43 are provided in each piston body 31, and the same number, specifically, four places are provided. Yes. The plurality of first passages 41 are arranged at the same distance from the central axis of the piston body 31, and the plurality of second passages 42 are also arranged at the same distance from the central axis of the piston body 31. The third passage 43 is also disposed at the same distance from the central axis of the piston body 31. The first passage 41 and the third passage 43 are alternately arranged at equal intervals in the circumferential direction of the piston body 31, and the second passage 42 matches the position of the piston body 31 in the circumferential direction with the first passage 41. ing.

  As shown in FIG. 2, a plurality of one side surfaces of the piston body 31 on the first chamber 19 side in the axial direction of the piston body 12 are arranged side by side in the circumferential direction of the piston body 31. Specifically, four frame-shaped first sheets 51 are provided. The plurality of first sheets 51 are independently formed at positions separated from each other in the piston body 31, are provided at equal intervals in the circumferential direction of the piston body 31, and are arranged in the axial direction of the piston body 31 as shown in FIG. 1. It protrudes toward the first chamber 19 which is the outside.

  As shown in FIG. 2, the plurality of first sheets 51 are individually provided so as to surround the opening 41 a on the first chamber 19 side of the corresponding one of the plurality of first passages 41. Specifically, each of the plurality of first sheets 51 is provided so as to surround the opening 41 a of one first passage 41. The openings 41a of the plurality of first passages 41 are arranged at the center position in the circumferential direction of the piston body 31 of the first seat 51 surrounding each of the first passages 41. An opening 41 a of the first passage 41 is opened in an inner passage 52 inside the first seat 51 provided by overlapping the axial positions of the first sheet 51 and the piston body 31. In other words, the first sheet 51 protrudes so as to surround the inner passage 52 communicating with the first passage 41. In addition, when the number of the 1st channel | paths 41 is doubled with respect to the 1st sheet | seat 51, for example, one of the 1st sheet | seats 51 surrounds the opening 41a of the 1st channel | path 41 of 2 places, and these opening 41a. Is opened in the inner passage 52. An opening 43 a on the first chamber 19 side of the third passage 43 is disposed at a central position between the first sheet 51 and the first sheet 51 adjacent in the circumferential direction of the piston body 31.

  Each of the plurality of first sheets 51 includes a pair of radial sheet portions 53 extending in the radial direction of the piston body 31, a first circumferential sheet portion 54 extending in the circumferential direction of the piston body 31, and a first circumferential sheet. The second circumferential seat portion 55 extends in the circumferential direction of the piston body 31 on the center side in the radial direction of the piston body 31 with respect to the portion 54. The first circumferential seat portion 54 connects the outer sides of the pair of radial seat portions 53 in the radial direction of the piston body 31, and the second circumferential seat portion 55 is the piston 12 of the pair of radial seat portions 53. The center sides in the radial direction are connected. In each of the plurality of first sheets 51, each first circumferential sheet portion 54 is arranged on the same circle centered on the central axis of the piston body 31, and each second circumferential sheet portion 55 is also a piston. They are arranged on the same circle centered on the central axis of the body 31. As shown in FIG. 1, each of the plurality of first sheets 51 has a front end surface 51 a that is a plane perpendicular to the central axis of the piston body 31, and the front end surfaces 51 a of all the first sheets 51 are They are arranged on the same plane.

  As shown in FIG. 2, on the one surface of the piston body 31 in the axial direction of the first chamber 19, the second sheet 61 is formed in an annular shape on the radial center side of the piston body 31 rather than the plurality of first sheets 51. However, the plurality of first sheets 51 are provided apart from each other. The second sheet 61 has a part that overlaps the position of the piston body 31 in the circumferential direction with respect to the first sheet 51 and is spaced apart in the radial direction of the piston body 31, and projects around the center of the piston body 31. It is a ring. Specifically, the second sheet 61 is formed so that the first sheet 51 and the second sheet 61 are separated over the entire circumference, and is formed in an annular shape centering on the center of the piston body 31. Yes. In other words, the second sheet 61 is separated from the first sheet 51 over 360 °. The second sheet 61 surrounds the openings 42a of the plurality of second passages 42 on the outer side in the radial direction of the piston body 31 with respect to the openings 42a on the first chamber 19 side of the plurality of second passages 42. The two passages 42 are provided away from the opening 42a. Specifically, the second sheets 61 are provided between the first sheets 51 and the openings 42a of all the second passages 42 so as to partition them.

  The second sheet 61 is formed in an annular shape centered on the central axis of the piston body 31. A groove 63 that is recessed in the axial direction of the piston body 31 is provided between the second circumferential sheet portion 55 and the second sheet 61 of each first sheet 51, in other words, a gap is provided. . As shown in FIG. 1, the second sheet 61 is provided so as to project toward the first chamber 19 side that is the outer side in the axial direction of the piston body 31, and the distal end surface 61 a on the projecting side is the central axis of the piston body 31. It becomes a plane orthogonal to.

  On one surface of the piston body 31 in the axial direction of the first chamber 19, as shown in FIG. 2, an annular center is formed on the radial center side of the piston body 31 with respect to the openings 42 a of the plurality of second passages 42. The sheet 66 is provided so as to be separated from the openings 42 a of the plurality of second passages 42. Specifically, the center seat 66 is provided on the inner side in the radial direction of the piston body 31 than the openings 42 a of all the second passages 42. The center sheet 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. As shown in FIG. 1, the center sheet 66 is provided so as to protrude toward the first chamber 19, which is the outer side in the axial direction of the piston body 31, and the tip end surface 66 a on the protruding side is in the center axis of the piston body 31. It is an orthogonal plane.

  Between the 2nd sheet | seat 61 and the center sheet | seat 66, it is the annular | circular shaped annular channel | path 67 in which all the opening 42a of the some 2nd channel | path 42 opens.

  The second sheet 61 projects lower than the first sheet 51, and the central sheet 66 projects in the same manner as the second sheet 61. In other words, the second sheet 61 is disposed such that the position of the leading end surface 61a on the protruding side is on the inner side in the protruding direction than the position of the leading end surface 51a on the protruding side of the first sheet 51. The position of the leading end surface 66a on the protruding side matches the position of the leading end surface 61a of the second sheet 61 in the protruding direction.

  The other surface on the second chamber 20 side in the axial direction of the piston body 31 constituting the other surface on the second chamber 20 side in the axial direction of the piston 12 is arranged in the circumferential direction of the piston body 31 as shown in FIG. A plurality of, specifically four, third sheets 71 are provided. The plurality of third sheets 71 are provided at equal intervals in the circumferential direction of the piston body 31 so as to protrude toward the second chamber 20 in the axial direction of the piston body 31 as shown in FIG.

  As shown in FIG. 3, the plurality of third sheets 71 are individually provided so as to surround the opening 43 b on the second chamber 20 side of the corresponding one of the plurality of third passages 43. Specifically, each of the plurality of third sheets 71 is provided so as to surround the opening 43 b of one third passage 43. The openings 43b of the plurality of third passages 43 are arranged at the center position in the circumferential direction of the piston body 31 of the third seat 71 surrounding each of the third passages 43. An opening 43b of the third passage 43 is opened in an inner passage 72 inside the third sheet 71 provided by overlapping the positions of the third sheet 71 and the piston body 31 in the axial direction. When the number of the third passages 43 is doubled with respect to the third sheet 71, for example, one of the third sheets 71 surrounds the openings 43b of the third passage 43 in a set of two places, and these openings 43b Is opened in the inner passage 72. The opening 41b of the first passage 41 on the second chamber 20 side and the second passage 42 on the second chamber 20 side at the center position between the third sheet 71 and the third sheet 71 adjacent in the circumferential direction of the piston body 31. An opening 42b is provided.

  Each of the plurality of third sheets 71 includes a pair of radial sheet portions 73 extending in the radial direction of the piston body 31 and a circumferential sheet portion 74 extending in the circumferential direction of the piston body 31. Common to all of the third seats 71, the central seat portion 75 is disposed closer to the center side in the radial direction of the piston body 31 than the circumferential seat portion 74. In the plurality of third sheets 71, the respective circumferential sheet portions 74 are arranged on the same circle centered on the central axis of the piston body 31. The circumferential seat portion 74 connects the outer sides in the radial direction of the piston body 31 of the pair of radial seat portions 73 that constitute the same third seat 71. The center seat portion 75 is provided so as to surround the entire circumference of the insertion hole 35 while connecting the center sides in the radial direction of the piston bodies 31 of the radial seat portions 73 of all the third seats 71. As shown in FIG. 1, the plurality of third sheets 71 including the common central seat portion 75 has a protruding end surface 71 a that is a plane perpendicular to the central axis of the piston body 31. The circumferential sheet portion 74 of the third sheet 71 is formed with a notch 76 that is recessed from the distal end surface 71 a and extends across the circumferential sheet portion 74 in the radial direction of the piston body 31.

  In the state where the mounting shaft portion 26 is inserted through the stepped portion 27 of the piston rod 13, the regulating member 81, the spacer disk 82, the disk valve 83, the piston 12, the disk valve 84, the spacer disk 85, The regulating member 86 is overlapped in this order, and in this state, the nut 14 is screwed to the male screw 28 protruding from the regulating member 86 of the mounting shaft portion 26. At this time, the piston 12 is in a posture in which the first sheet 51, the second sheet 61, and the center sheet 66 face the nut 14 side, and the third sheet 71 faces the stepped portion 27 side.

  By restricting the nut 14 to the male screw 28, the restricting member 81, the spacer disc 82, the disc valve 83, the piston 12, the disc valve 84, the spacer disc 85, and the restricting member 86 are all regulated in the radial direction by the mounting shaft portion 26. In this laminated state, the stepped portion 27 of the piston rod 13 and the nut 14 are sandwiched. Then, at least the inner peripheral side of these is fixed so as not to move in the axial direction with respect to the piston rod 13. Each of the disk valve 83 and the disk valve 84 is clamped such that only the inner peripheral side is not movable in the axial direction with respect to the piston rod 13.

  The restricting member 81 has an annular shape, and the attachment shaft portion 26 is fitted on the inner peripheral side. The regulating member 81 has an outer diameter larger than the outer diameter of the stepped portion 27. The spacer disk 82 has an annular shape, and the mounting shaft portion 26 is fitted to the inner peripheral side. The outer diameter of the spacer disk 82 is smaller than the outer diameter of the regulating member 81 and slightly larger than the outer diameter of the stepped portion 27. Large diameter.

  The disk valve 83 is configured by laminating a plurality of single disks 91 having the same outer diameter. Each of the plurality of single disks 91 has an annular shape, and the mounting shaft portion 26 is fitted to the inner peripheral side. These single disks 91 have leading ends on the protruding side of the third sheets 71 having a plurality of outer diameters. The diameter of the surface 71a is larger than twice the maximum distance from the central axis of the piston 12. Of the plurality of single disks 91, the single disk 91 arranged closest to the piston 12 comes into contact with the leading end surface 71 a of the third sheet 71, and this single disk 91 is in contact with the leading end surface 71 a of the third sheet 71. The disc valve 83 closes the second chamber 20 side of the inner passage 72 that communicates with the third passage 43.

  Here, the notch 76 formed in the third seat 71 of the piston 12 allows the inner periphery side and the outer periphery side of the third seat 71 to be separated even when the disc valve 83 is in contact with the front end surface 71a of the third seat 71. The second passage 20 and the inner passage 72 and the third passage 43 are communicated with each other. That is, the notch 76 forms a fixed orifice with the disc valve 83 in the closed state.

  The opening 41 b on the second chamber 20 side of the first passage 41 and the opening 42 b on the second chamber 20 side of the second passage 42 are not closed by the disc valve 83 and are always in communication with the second chamber 20. .

  The restricting member 81 is thicker and more rigid than the single disk 91 constituting the disk valve 83, and when the disk valve 83 is deformed in a direction away from the third seat 71, the restriction member 81 is the third sheet. 71 abuts against a single disk 91 on the opposite side to 71 and restricts deformation beyond a predetermined level.

  The disk valve 84 includes a single small-diameter disk 95 having the shape shown in FIG. 4 and a plurality of large-diameter disks, specifically three large-diameter disks as shown in FIG. 96 is laminated. In the disk valve 84, the small diameter disk 95 is disposed closest to the piston 12 in the axial direction of the piston 12, and a plurality of large diameter disks 96 are stacked opposite to the piston 12 of the small diameter disk 95.

  The small-diameter disk 95 has an annular shape, and the mounting shaft portion 26 is fitted on the inner peripheral side. The outer diameter is larger than the outer diameter of the front end surface 61 a of the second sheet 61, and the first sheet 51. The tip surface 51a has a smaller diameter than twice the minimum distance from the central axis of the piston 12. As a result, the small-diameter disk 95 comes into contact with the front end surface 61 a of the second sheet 61 and the front end surface 66 a of the central sheet 66. The small-diameter disk 95 is clamped on the central sheet 66 side in the radial direction and is always in contact with the central sheet 66, while the second sheet 61 side in the radial direction is separated from the second sheet 61. The small-diameter disk 95 closes the first chamber 19 side of the second passage 42 and the annular passage 67 while being seated on the second seat 61.

  The small-diameter disk 95 is formed with a notch 97 extending on the outer peripheral side so as to straddle the front end surface 61 a of the second sheet 61 in the radial direction of the piston 12. As shown in FIG. 4, the notch 97 is U-shaped and extends out of the outer periphery of the small-diameter disk 95, and penetrates the small-diameter disk 95 in the plate thickness direction. In the small-diameter disk 95, a plurality of such notches 97 are formed at equal intervals in the circumferential direction, specifically, four places. As shown in FIG. 5, the notch 97 connects the inner peripheral side and the outer peripheral side of the second sheet 61 even when the small-diameter disk 95 is in contact with the leading end surface 61a of the second sheet 61, thereby The second passage 42 and the annular passage 67 on the inner peripheral side of 61 and the first chamber 19 on the outer peripheral side of the second sheet 61 are communicated with each other through a gap between the first sheet 51 and the first sheet 51. That is, the notch 97 forms a fixed orifice with the second sheet 61. In addition, without providing the notch 97 in the small diameter disc 95, the second sheet 61 is cut so that the inner peripheral side and the outer peripheral side communicate with each other even when the small diameter disc 95 is in contact with the front end surface 61a of the second sheet 61. A notch may be provided, and both the notch of the second sheet 61 and the notch 97 of the small diameter disk 95 may be provided.

  Here, the difference in the axial distance of the piston 12 between the front end surface 51a of the first sheet 51, the front end surface 61a of the second sheet 61, and the front end surface 66a of the center sheet 66 is equal to the thickness of the small diameter disk 95. It has become.

  The plurality of large-diameter disks 96 are common parts having the same size, and have an annular shape with the attachment shaft portion 26 fitted on the inner peripheral side. The plurality of large-diameter disks 96 have an outer diameter larger than twice the maximum distance from the central axis of the piston 12 of the front end surface 51a of the first sheet 51. The large-diameter disk 96 closest to the small-diameter disk 95 comes into contact with the front end surface 51a and is seated on the first sheet 51. In this state, the first chamber 41 side of the first passage 41 and the inner passage 52 is closed. . The first sheet 51 and the large-diameter disk 96 are not formed with notches that allow the first passage 41 and the inner passage 52 to communicate with the first chamber 19 at all times.

  Therefore, the disk valve 84 including the small-diameter disk 95 and the plurality of large-diameter disks 96 is seated on the plurality of first seats 51 and one annular second seat 61. As shown in FIG. 1, the opening 43 a on the first chamber 19 side of the third passage 43 is not closed by the disk valve 84 and is always in communication with the first chamber 19.

  The spacer disk 85 has an annular shape, and the mounting shaft portion 26 is fitted on the inner peripheral side. The outer diameter of the spacer disk 85 is slightly larger than the outer diameter of the front end surface 66a of the central sheet 66, and the second sheet. The diameter is smaller than the inner diameter of the front end surface 61 a of 61. The restricting member 86 has an annular shape, and the attachment shaft portion 26 is fitted on the inner peripheral side. The restricting member 86 has a larger diameter than the outer diameter of the front end surface 61 a of the second sheet 61. The spacer disks 82 and 85 are common parts, and the regulation members 81 and 86 are also common parts.

  In the shock absorber 10, in the extension stroke in which the piston rod 13 moves to the extension side that increases the amount of protrusion from the cylinder 11, the pressure in the second chamber 20 is higher than the pressure in the first chamber 19 by the piston 12 that moves together with the piston rod 13. On the other hand, the working fluid in the second chamber 20 is introduced into the plurality of first passages 41 from the respective openings 41b that are always open, exits from the openings 41a to the inner passage 52, and enters the large-diameter disc 96 of the disc valve 84. Works. On the other hand, the working fluid in the second chamber 20 is introduced into the plurality of second passages 42 from the respective open openings 42b and exits from the openings 42a to the annular passage 67. It acts on the disk 96.

  At this time, when the speed of the piston 12 is low, the working fluid in the inner passage 52 does not separate the large-diameter disc 96 of the disc valve 84 from the first seat 51, and the working fluid in the annular passage 67 does not move away from the disc valve. The small-diameter disk 95 of 84 passes through the notch 97 formed in the small-diameter disk 95 of the disk valve 84 without flowing away from the second seat 61 and flows into the first chamber 19. Thereby, since the cross-sectional area of the flow path becomes constant, a damping force having an orifice characteristic (a damping force is approximately proportional to the square of the piston speed) is generated. At this time, the working fluid that flows out from the second passage 42 through the notch 97 flows as shown by an arrow A in FIG. 5, and is outside the second seat 61 in the radial direction of the piston 12. It flows into the first chamber 19 through a gap between the first sheet 51 and the first sheet 51 that are provided apart in the circumferential direction.

  When the speed of the piston 12 is higher than the above, the working fluid in the inner passage 52 opens the large-diameter disc 96 of the disc valve 84 away from the first seat 51, and the working fluid in the annular passage 67 is opened. The small diameter disk 95 of the valve 84 is separated from the second seat 61 and opened. Thereby, the working fluid flows from the second chamber 20 to the first chamber 19 through the plurality of first passages 41 at a flow rate corresponding to the valve opening amounts of the large-diameter disc 96 and the plurality of first seats 51, The working fluid flows through the plurality of second passages 42 with a flow path cross-sectional area corresponding to the valve opening amount of the small-diameter disk 95 and the annular second seat 61. For this reason, a damping force having a valve characteristic (a damping force is substantially proportional to the piston speed) is generated. At this time, a part of the working fluid flowing out from the plurality of second passages 42 through the gaps between the small-diameter disk 95 and the annular second sheet 61 is located outside the second sheet 61 in the radial direction of the piston 12. Flows in the first chamber 19 through a gap between the first sheet 51 and the first sheet 51 that are spaced apart in the circumferential direction.

  In other words, when the piston rod 13 moves to the extending side and the piston 12 slides in the cylinder 11 integrally with the first passage 41 and the second passage 42, the working fluid flows into the first passage 41 and the second passage 42 due to the sliding. It flows from the two chambers 20 toward the first chamber 19. The plurality of first passages 41, the plurality of inner passages 52, the plurality of second passages 42, and the annular passage 67 of the piston 12, and the plurality of first seats 51 and the annular second seat 61 of the piston 12 are seated on these. The disc valve 84 constitutes an extension-side damping force generation mechanism 100 that is provided in the piston 12 and generates a damping force by controlling the flow of the working fluid. The damping force generation mechanism 100 is disposed on the first chamber 19 side of the piston 12.

  In the above extension stroke, in addition to the above, the working fluid flows from the second chamber 20 to the first chamber 19 through the notch 76, the inner passage 72, and the third passage 43 of the third sheet 71.

  On the other hand, in the contraction stroke in which the piston rod 13 moves to the contraction side to increase the amount of entry into the cylinder 11, the pressure in the first chamber 19 is increased more than the pressure in the second chamber 20 by the piston 12 that moves together with the piston rod 13. The working fluid in the first chamber 19 is introduced into the plurality of third passages 43 from the respective openings 43a that are normally open, exits from the openings 43b to the corresponding inner passages 72, and acts on the disk valve 83.

  At this time, when the speed of the piston 12 is low, the working fluid in the inner passage 72 passes through the notch 76 formed in the third seat 71 without causing the disc valve 83 to be separated from the third seat 71. It flows into the second chamber 20. Thereby, since the cross-sectional area of the flow path becomes constant, a damping force having an orifice characteristic (a damping force is approximately proportional to the square of the piston speed) is generated.

  When the speed of the piston 12 is higher than the above, the working fluid in the inner passage 72 opens the disc valve 83 away from the third seat 71. As a result, the flow passage according to the valve opening amounts of the disk valve 83 and the plurality of third seats 71 from the first chamber 19 to the second chamber 20 via the plurality of third passages 43 and the plurality of inner passages 72 is cut off. The working fluid flows in the area. For this reason, a damping force having a valve characteristic (a damping force is substantially proportional to the piston speed) is generated.

  That is, 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 the third passage 43, the working fluid is moved from the first chamber 19 to the second chamber by this sliding. It will flow towards 20. A plurality of third passages 43 and a plurality of inner passages 72 of the piston 12, a plurality of third seats 71 of the piston 12, and a disk valve 83 seated on these are provided in the piston 12 to control the flow of working fluid. Thus, a contraction-side damping force generation mechanism 101 that generates damping force is configured. The damping force generation mechanism 101 is disposed on the second chamber 20 side of the piston 12.

  In the above-described contraction stroke, in addition to the above, the working fluid is transferred from the first chamber 19 to the second chamber 20 through the notch 97 of the small-diameter disk 95 of the disk valve 84, the annular passage 67 and the second passage 42. Flowing.

  Patent Document 1 described above discloses a shock absorber in which a piston is provided with a plurality of valve seat portions arranged in the radial direction. In the shock absorber having such a configuration, the working fluid flowing out from the inner periphery of the innermost peripheral valve seat portion passes through the plurality of valve seat portions toward the outer peripheral side. Even when it is desired to suppress the inclination of the damping force with respect to the piston speed in the valve characteristics caused by the opening of the disc valve, this may not be suppressed as low as desired. That is, the damping force characteristic may be high particularly in the high speed region of the piston speed.

  On the other hand, the shock absorber 10 of the first embodiment is provided with a plurality of first sheets 51 protruding in a circumferential direction of the piston 12 so as to surround the inner passage 52 communicating with the first passage 41. The first seat 51 is located closer to the center of the piston 12 in the radial direction than the first seat 51, and has a portion that is spaced apart from the first seat 51 and protrudes around the center of the piston 12 outside the opening 42 a of the second passage 42. Two sheets 61 are provided. Therefore, when the disc valve 84 is opened, the gap between the first seat 51 and the first seat 51 spaced apart from the opening 42a of the second passage 42 on the inner peripheral side of the second seat 61 in the circumferential direction of the piston 12 is provided. Since the working fluid can flow smoothly to the first chamber 19, the influence of the working fluid flowing from the first passage 41 to the first chamber 19 on the working fluid flowing from the second passage 42 to the first chamber 19 is suppressed. Can do. Therefore, the inclination of the damping force with respect to the piston speed in the valve characteristics can be kept low. For example, as compared with the conventional shock absorber indicated by the broken line Y1 in FIG. 6, the shock absorber 10 of the first embodiment indicated by the solid line Y2 in FIG. 6 can suppress the inclination of the damping force with respect to the piston speed in the valve characteristic to be low. It becomes possible. Therefore, an increase in the damping force characteristic can be suppressed in the high speed region of the piston speed.

  Moreover, the above-described Patent Document 1 discloses a shock absorber in which a plurality of valve seat portions are provided on a piston side by side in the circumferential direction. In the shock absorber having such a configuration, if a notch for the fixed orifice is provided on the disk valve side, positioning of the disk valve in the circumferential direction becomes necessary.

  In contrast, the shock absorber 10 of the first embodiment is provided with a plurality of first sheets 51 protruding so as to surround the opening 41a of the first passage 41 in the circumferential direction of the piston 12, and these first sheets An annular second sheet 61 protruding so as to surround the opening 42a of the second passage 42 is provided on the radial center side of the piston 12 with respect to 51, and a notch 97 for a fixed orifice is provided on the second sheet 61 side. Provided. At that time, the disk valve 84 includes a large-diameter disk 96 seated on a plurality of first seats 51 arranged side by side in the circumferential direction of the piston 12 and a small-diameter disk 95 seated on an annular second seat 61. Thus, a notch 97 is provided on the second sheet 61 side. Thereby, even if the piston 12 is provided with a plurality of first sheets 51 arranged in the circumferential direction, positioning of the disc valve 84 in the circumferential direction can be made unnecessary. Accordingly, the positioning work is not required, so that the mounting is easy, and the positioning structure is also unnecessary, so that the structure is simplified.

  Even if the notch 97 is provided in the small-diameter disk 95, it is seated on the annular second sheet 61, so that positioning in the circumferential direction can be made unnecessary. In addition, when it is desired to change the size of the notch 97, only the small-diameter disk 95 can be changed. Therefore, since it is not necessary to change the piston 12, the damping force characteristic can be easily tuned without increasing the types of the piston 12.

  In addition, the groove 63 is provided between the second sheet 61 and the second circumferential sheet 55 on the center side in the radial direction of the piston 12 relative to the first circumferential sheet 54 of the first sheet 51. The disc valve 84 can be easily separated from the first seat 51 and the second seat 61.

  Further, since the first sheet 51 and the second sheet 61 are separated over the entire circumference, the first sheet 51 is separated from the opening 42a of the second passage 42 in the circumferential direction of the piston 12 when the disc valve 84 is opened. The working fluid can flow more smoothly into the first chamber 19 through the gap between the sheet 51 and the first sheet 51. Therefore, the influence of the working fluid flowing from the first passage 41 to the first chamber 19 on the working fluid flowing from the second passage 42 to the first chamber 19 can be further suppressed. Therefore, the inclination of the damping force with respect to the piston speed in the valve characteristics can be further suppressed.

  In the first embodiment, the disc valve 83, the piston 12 and the disc valve 84 are collectively arranged and reversed in the axial direction of the piston rod 13, so that the damping force generating mechanism 100 is compressed on the contraction side. The damping force generation mechanism 101 may be the extension-side damping force generation mechanism 101. In this case, when the piston 12 moves to the contraction side, the working fluid is introduced from the first chamber 19 into the first passage 41 and the second passage 42, and the working fluid introduced into the second passage 42 is The working fluid that flows into the second chamber 20 through a notch 97 formed in the small-diameter disk 95 of the disk valve 84 or introduced into the second passage 42 passes through the gap between the small-diameter disk 95 and the second seat 61. The working fluid that flows into the second chamber 20 and is introduced into the first passage 41 flows into the second chamber 20 through a gap between the large-diameter disk 96 and the first sheet 51.

“Second Embodiment”
Next, the second embodiment will be described mainly based on FIGS. 7 to 8 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.

  In the second embodiment, as shown in FIG. 7, the distance in the axial direction of the piston 12 between the front end surface 51 a of the first sheet 51 of the piston 12 and the front end surface 61 a of the second sheet 61 is greater than that of the first embodiment. The leading end surface 66a of the central sheet 66 is lower in the protruding direction than the leading end surface 61a of the second sheet 61. In the disk valve 84 of the second embodiment, a plurality of, specifically, four small-diameter disks 95A to 95D are sequentially stacked on the front end surface 66a of the central sheet 66, and a plurality of these, specifically, four A large-diameter disk 96 similar to that of the first embodiment is laminated.

  A small-diameter disk 95 </ b> A (blocking disk) placed on the front end surface 66 a of the central sheet 66 has an annular shape, and the mounting shaft portion 26 is fitted on the inner peripheral side, and the outer diameter is the second sheet 61. The diameter is smaller than the inner diameter of the front end surface 61 a and larger than the outer diameter of the front end surface 66 a of the center sheet 66.

  A small diameter disk 95B (notched disk) adjacent to the large diameter disk 96 side of the small diameter disk 95A has an annular shape and the mounting shaft portion 26 is fitted on the inner peripheral side, and the outer diameter is smaller than that of the small diameter disk 95A. Is larger than the outer diameter of the front end surface 61a of the second sheet 61 and smaller than twice the minimum distance of the front end surface 51a of the first sheet 51 from the central axis of the piston 12. It has become. The small-diameter disk 95B comes into contact with the front end surface 61a and is seated on the second seat 61, and in this state, the second passage 42 and the annular passage 67 close the first chamber 19 side. As shown in FIG. 8, a plurality of, specifically, four notches 97 similar to those in the first embodiment are formed on the outer peripheral side of the small-diameter disk 95B.

  The small-diameter disk 95B has a first opening 95Ba penetrating in the thickness direction on the inner peripheral side of the radial intermediate position. The first opening 95Ba has an arc shape along the inner peripheral edge of the small-diameter disk 95B, and a plurality, specifically two, are formed side by side in the circumferential direction of the small-diameter disk 95B. As shown in FIG. 7, the small diameter disk 95 </ b> B is in a state of being seated on the second sheet 61, and the notch 97 communicates the inner peripheral side and the outer peripheral side of the second sheet 61.

  A small-diameter disk 95C (first communication disk) adjacent to the small-diameter disk 95B on the opposite side of the small-diameter disk 95A has the same outer diameter as the small-diameter disk 95B. As shown in FIG. A plurality of second openings 95Ca similar to the opening 95Ba are formed. When the small-diameter disk 95C is overlaid on the small-diameter disk 95B, the outer peripheral side covers the notch 97 and the inner peripheral second opening 95Ca communicates with the first opening 95Ba regardless of the positional relationship in the circumferential direction.

  As shown in FIG. 7, the small-diameter disk 95D (second communication disk) adjacent to the small-diameter disk 95C on the opposite side of the small-diameter disk 95B and adjacent to the large-diameter disk 96 has the same outer diameter as the small-diameter disks 95B and 95C. As shown in FIG. 8, a third opening 95 </ b> Da penetrating in the plate thickness direction is provided on the inner peripheral side of the radial intermediate position. The third opening 95Da has an arc shape along the inner peripheral edge of the small-diameter disk 95D, and is formed in a plurality, specifically three, along the circumferential direction of the small-diameter disk 95D. Further, the small diameter disk 95D is formed with a radial passage 95Db extending from each of the plurality of third openings 95Da to the outer peripheral end of the small diameter disk 95D. When the small-diameter disk 95D is superimposed on the small-diameter disk 95C, the second opening 95Ca and the third opening 95Da communicate with each other regardless of the positional relationship in the circumferential direction. The large-diameter disk 96 is overlaid on the small-diameter disk 95D, whereby the large-diameter disk 96 closes the side opposite to the small-diameter disk 95C of the plurality of third openings 95Da and the plurality of radial passages 95Db. The radial passage 95Db and the third opening 95Da through which the small-diameter disk 95D passes outwardly communicates the first chamber 19 with the second opening 95Ca of the small-diameter disk 95C and the first opening 95Ba of the small-diameter disk 95B.

  The small-diameter disk 95A provided on the opposite side of the small-diameter disk 95B to the small-diameter disk 95C closes the small-diameter disk 95A side of the first opening 95Ba when it is superimposed on the small-diameter disk 95B. However, the small diameter disk 95A does not overlap the notch 97 of the small diameter disk 95B. As shown by arrow B in FIG. 7, the small-diameter disk 95 </ b> A is configured so that the working fluid flows from the second passage 42 of the piston 12 to the first chamber 19 through the annular passage 67 and the notch 97. The opening 95Ba is closed. Further, as shown by an arrow C in FIG. 7, the small-diameter disc 95A has an annular passage 67 and a second passage from the first chamber 19 through the radial passage 95Db, the third opening 95Da, the second opening 95Ca, and the first opening 95Ba. When the working fluid is about to flow through the passage 42, the first opening 95Ba is communicated with the annular passage 67 and the second passage 42 apart from the small-diameter disk 95B to allow this flow. The small diameter disk 95A is thinner and less rigid than the small diameter disks 95B to 95D, and functions as a check valve that is easy to open.

  The large-diameter disk 96 superimposed on the small-diameter disk 95D is seated on the first seat 51 as in the first embodiment.

  According to the second embodiment, in the extension-side damping force generation mechanism 100, in the extension stroke in which the piston rod 13 and the piston 12 move to the extension side, the damping force is generated as in the first embodiment. become. On the other hand, in the contraction stroke in which the piston rod 13 and the piston 12 move to the contraction side, the working fluid in the first chamber 19 flows through the gap between the notch 97 and the second sheet 61 (opposite to the arrow B in FIG. 7). In addition to the flow in the direction, as indicated by an arrow C in FIG. 7, the radial passage 95Db and the third opening 95Da of the small-diameter disk 95D, the second opening 95Ca of the small-diameter disk 95C, and the first opening 95Ba of the small-diameter disk 95B The small-diameter disk 95A is opened through the flow from the annular passage 67 and the second passage 42 to the second chamber 20.

  As a result, in the damping force generation mechanism 100 on the extension side, the fixed orifice that was the flow path cross-sectional area of the gap between the notch 97 and the second sheet 61 in the extension stroke becomes the flow path cross-sectional area in the contraction stroke. The flow passage cross-sectional area of the flow path for opening the small-diameter disk 95A is added and changed through the radial passage 95Db and the third opening 95Da of the small-diameter disk 95D, the second opening 95Ca of the small-diameter disk 95C, and the first opening 95Ba of the small-diameter disk 95B. . Thus, the flow path cross-sectional area of the fixed orifice of the damping force generation mechanism 100 can be changed between the extension stroke and the contraction stroke.

  Further, since the small-diameter disk 95A has a smaller plate thickness and lower rigidity than the small-diameter disks 95B to 95D, the small-diameter disk 95A can be easily opened in the contraction stroke.

  Also in the second embodiment, the piston 12 and the disk valve 84 may be integrated and reversed in the axial direction of the piston rod 13. In this case, the small-diameter disk 95A has a first opening 95Ba of the small-diameter disk 95B when the working fluid flows from the first chamber 19 to the second chamber 20 via the second passage 42 and the annular passage 67 of the piston 12 in the contraction stroke. Block. In the extension stroke, the small diameter disc 95A is removed from the second chamber 20 through the radial passage 95Db and the third opening 95Da of the small diameter disc 95D, the second opening 95Ca of the small diameter disc 95C, and the first opening 95Ba of the small diameter disc 95B. When the working fluid is about to flow from the annular passage 67 and the second passage 42 to the first chamber 19 by the opening flow, the small-diameter disk 95A is separated from the small-diameter disk 95B and the first opening 95Ba is separated from the annular passage 67 and the second passage 95. This flow is allowed in communication with the passage 42.

“Third Embodiment”
Next, the third embodiment will be described mainly based on FIGS. 9 and 10 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.

  In the third embodiment, the piston body 31 has a substantially disc shape and a first piston body 31A in which the sliding contact member 33 is mounted on the outer peripheral portion, and a substantially disc shape having a thickness smaller than that of the first piston body 31A. The second piston body 31B is disposed on the first chamber 19 side in the axial direction of the first piston body 31A. The first piston body 31A and the second piston body 31B are each formed by sintering.

  The first piston body 31A is formed with an insertion hole 35A through which the piston rod 13 is inserted in the center in the radial direction so as to penetrate in the axial direction, and the opening on the second piston body 31B side of the insertion hole 35A. A positioning recess 121 that is recessed in the axial direction and the radial direction is partially formed in the circumferential direction. The first piston body 31A is provided with a central seat portion 75, a third sheet 71, and an inner passage 72 inside the third seat 71 on the side opposite to the second piston body 31B. A third passage 43 penetrating in the axial direction is provided. A disk valve 83 is provided on the opposite side of the first piston body 31A from the second piston body 31B.

  Further, the first piston body 31A is formed with a common passage 125 that opens on the opposite side to the second piston body 31B on the outer side in the radial direction than the third seat 71 and penetrates in the axial direction. The common passage 125 is formed at a plurality of locations (only one location is shown in FIG. 9 because of the cross-section in FIG. 9) at intervals in the circumferential direction of the first piston body 31A, and between the third passage 43 and the first piston body 31A. Alternatingly arranged in the circumferential direction.

  The second piston body 31B is formed with an insertion hole 35B through which the piston rod 13 is inserted in the center in the radial direction so as to penetrate in the axial direction. The opening of the insertion hole 35B on the first piston body 31A side is formed. On the outer side in the radial direction of the part, a positioning convex part 131 protruding in the axial direction is partially formed in the circumferential direction. The second piston body 31B has a passage notch 132 recessed in the axial direction on the first piston body 31A side so as to come out from the position between the insertion hole 35B and the outer periphery to the outer periphery. A plurality of openings are formed (in FIG. 9, only one is shown because of the cross section). Further, in the second piston body 31B, on the first piston body 31A side, there are a plurality of passage recesses 133 that are recessed in the axial direction between the insertion hole 35B and the outer peripheral portion at intervals in the circumferential direction (in FIG. In this relation, only one location is shown). The passage notches 132 and the passage recesses 133 are alternately arranged in the circumferential direction of the second piston body 31B.

  By fitting the positioning convex portion 131 to the positioning concave portion 121 of the first piston body 31A, the second piston body 31B is positioned in the circumferential direction with respect to the first piston body 31A. The positions of the passage notch 132 and the third passage 43 in the circumferential direction of the piston 12 are matched, and the positions of the passage recess 133 and the common passage 125 in the circumferential direction of the piston 12 are matched. The third passage 43 is always in communication with the first chamber 19 via the passage notch 132, and the first chamber 19 and the second chamber 20 can be communicated with each other.

  In the second piston body 31B, a first passage 41 and a second passage 42 both extending in the axial direction of the second piston body 31B are formed at the position of the passage recess 133. The opening 41 b on the second chamber 20 side of the first passage 41 and the opening 42 b on the second chamber 20 side of the second passage 42 are open to the passage recess 133. Therefore, the first passage 41 and the second passage 42 are always in communication with the second chamber 20 via the passage recess 133 and the common passage 125, and the first chamber 19 and the second chamber 20 are in communication with each other. Is possible. The second passage 42 is arranged at a position closer to the insertion hole 35 </ b> B than the first passage 41.

  As shown in FIG. 10, a plurality of first passages 41 and a plurality of second passages 42 are provided, and the same number, specifically, five places are provided. The flow passage cross-sectional area of the second passage 42 is larger than the flow passage cross-sectional area of the first passage 41. The first passage 41 and the second passage 42 are aligned with each other in the circumferential direction of the second piston body 31B.

  As shown in FIG. 9, the second piston body 31B is similar to the first embodiment in which the extension-side damping force generation mechanism 100 is configured on the outer peripheral side of one surface opposite to the first piston body 31A in the axial direction. As shown in FIG. 10, a plurality of, specifically five, sheets 1 are provided in the circumferential direction of the second piston body 31B. Further, as shown in FIG. 9, an extension side damping force is generated on the one surface opposite to the first piston body 31A in the axial direction of the second piston body 31B at an intermediate position in the radial direction of the second piston body 31B. A second sheet 61 similar to that of the first embodiment constituting the mechanism 100 is provided. Further, a central seat 66 similar to that of the first embodiment is provided on one surface of the second piston body 31B opposite to the first piston body 31A in the axial direction on the central axis line side in the radial direction of the second piston body 31B. Is provided.

  As shown in FIG. 10, the second sheet 61 has a front end surface 61 a of the second sheet 61 at a central position between the first sheet 51 and the first sheet 51 adjacent to each other in the circumferential direction of the second piston body 31 </ b> B. A notch 141 is formed which is recessed from the inside and communicates between the inner peripheral side and the outer peripheral side of the second sheet 61. The notch 141 is formed by coining, for example.

  As shown in FIG. 9, the first sheet 51, the second sheet 61, and the center sheet 66 protrude equally, in other words, the protruding end surface 51 a of the first sheet 51 and the protrusion of the second sheet 61. The position of the piston 12 in the axial direction coincides with the front end surface 61a on the side and the front end surface 66a on the protruding side of the central sheet 66.

  A disk valve 84 constituting the damping force generation mechanism 100 is disposed on the opposite side of the second piston body 31B from the first piston body 31A. The disk valve 84 of the third embodiment includes a plurality of large diameter disks 142, a plurality of intermediate diameter disks 143 having a smaller outer diameter than the large diameter disk 142, and an outer diameter smaller than the intermediate diameter disk 143. A plurality of small-diameter disks 144 are laminated, and a plurality of intermediate-diameter disks 143 are arranged on the opposite side of the plurality of large-diameter disks 142 from the second piston body 31B. A plurality of small-diameter disks 144 are arranged on the opposite side of the large-diameter disk 142.

  The outer diameter of the large-diameter disk 142 is larger than twice the maximum distance from the central axis of the piston 12 of the tip surface 51a of the first sheet 51, and the first sheet 51, the second sheet 61, and Contact the center sheet 66. The intermediate diameter disk 143 has the same outer diameter as the outer diameter of the front end surface 61 a of the second sheet 61. The small diameter disk 144 has an outer diameter larger than the outer diameter of the spacer disk 85.

  The disk valve 84 is seated on the plurality of first sheets 51 and the annular second sheet 61 on the large-diameter disk 142, the inner passage 52 inside the first sheet 51, the second sheet 61, the center sheet 66, The annular passage 67 between them is closed. The notch 141 of the second sheet 61 allows the inner side and the outer side of the second sheet 61 to communicate with each other even when the disc valve 84 is in contact with the front end surface 61 a of the second sheet 61. The annular passage 67 and the second passage 42 on the inner peripheral side of the second seat 61 are communicated with the first chamber 19 on the outer peripheral side of the second seat 61. That is, the notch 141 forms a fixed orifice with the disc valve 84.

  In the third embodiment, since the notch 141 as a fixed orifice is provided in the annular second sheet 61, the disc valve 84 can be attached without being positioned in the circumferential direction. Accordingly, the positioning operation of the disc valve 84 is not required, so that the mounting is easy, and the positioning structure is also unnecessary, so that the structure is simplified.

“Fourth Embodiment”
Next, the fourth embodiment will be described mainly based on FIG. 11 with a focus on differences from the third embodiment. In addition, about the site | part which is common in 3rd Embodiment, it represents with the same name and the same code | symbol.

  In the fourth embodiment, the second sheet 61 of the second piston body 31 </ b> B protrudes lower than the first sheet 51, and the center sheet 66 protrudes in the same manner as the second sheet 61. In other words, in the second sheet 61, the position of the protruding end surface 61a is lower in the protruding direction than the position of the protruding end surface 51a of the first sheet 51, and the central sheet 66 is positioned on the protruding side. The position of the leading end surface 66 a of the second sheet 61 coincides with the position of the leading end surface 61 a of the second sheet 61. Further, the notch 141 of the third embodiment is not provided in the second piston body 31B. It is also possible to provide a notch 141 in the second piston body 31B.

  The disc valve 84 constituting the damping force generating mechanism 100 is provided with a small-diameter disc 95 which is different from the first embodiment in that the notch 97 is not provided. Similarly to the third embodiment, even when the notch 141 of the second sheet 61 is in contact with the front end surface 61a of the second sheet 61 with the small-diameter disk 95, the inner side and the outer side of the second sheet 61 are separated. The annular passage 67 and the second passage 42 and the first chamber 19 are communicated with each other.

  The disk valve 84 is opposite to the plurality of large-diameter disks 142 similar to the third embodiment and the small-diameter disk 95 of the large-diameter disk 142 that are stacked on the opposite side of the small-diameter disk 95 from the second piston body 31B. The contact disk 151 stacked on the side, the inclined disk 152 stacked on the opposite side of the large-diameter disk 142 of the contact disk 151, and a plurality of attached disks stacked on the opposite side of the contact disk 151 of the inclined disk 152. Force disk 153.

  The contact disk 151, the inclined disk 152, and the biasing disk 153 have the same outer diameter as that of the small-diameter disk 95. The inclined disk 152 has a protrusion 155 protruding in the plate thickness direction on the outer peripheral side. The protrusion 155 is brought into contact with the contact disk 151 and the inner peripheral side is clamped in the axial direction, thereby The side is inclined so as to be away from the contact disk 151. The urging disk 153 that contacts the contact disk 151 is also inclined so that the outer peripheral side is separated from the contact disk 151 along the contact disk 151. Therefore, the contact disk 151, the inclined disk 152, and the biasing disk 153 bias the small diameter disk 95 so as to press the front end surface 61 a of the second sheet 61 through the large diameter disk 142.

“Fifth Embodiment”
Next, the fifth embodiment will be described mainly based on FIG. 12 with a focus on differences from the third embodiment. In addition, about the site | part which is common in 3rd Embodiment, it represents with the same name and the same code | symbol.

  In 5th Embodiment, the connection sheet | seat 161 which connects the 2nd sheet | seat 61 and each of the several 1st sheet | seat 51 separately is provided in the 2nd piston body 31B of 3rd Embodiment. One connecting sheet 161 is provided for each of the first sheets 51. The connection sheet 161 extends along the radial direction of the second piston body 31B, and is disposed at the center position in the circumferential direction of the second piston body 31B of the first sheet 51 to be connected. The second sheet 61 of the fifth embodiment is not separated from the first sheet 51 by 360 °, but most of the second sheet 61 is separated.

  And the notch 141 extended along the connection sheet 161 and recessed rather than the front end surface 161a of the protrusion direction of the connection sheet 161 is formed in the center position of the connection sheet 161 in the circumferential direction of the second piston body 31B. Yes. One notch 141 is provided for each of the connection sheets 161. The notch 141 communicates the inner peripheral side and the outer peripheral side of the second sheet 61, as in the third embodiment, and the radial direction of the second piston body 31 </ b> B of the second circumferential seat portion 55 of the first sheet 51. The inside and outside are communicated. That is, in the fifth embodiment, the notch 141 communicates the inner passage 52 inside the first sheet 51 and the annular passage 67 on the center side in the radial direction of the second piston body 31B of the second sheet 61. Yes.

  The second sheet 61 of the fifth embodiment has an arc shape centered on the center of the piston body 31 that overlaps the first sheet 51 in the circumferential direction of the piston body 31 and is spaced apart in the radial direction of the piston body 31. The arcuate portion 171 is located closer to the center side in the radial direction of the piston body 31 than the first seat 51.

  In the fifth embodiment, the width β in the circumferential direction of the second piston body 31B of the front end surface 161a of the connecting sheet 161 is subtracted from the width α in the circumferential direction of the second piston body 31B of the front end surface 51a of the first sheet 51. The value is larger than the width β of the tip surface 161a. That is, a relationship of α−β> β and a relationship of α> 2β are established. In other words, the full width α-β of the portion of the tip surface 51a that faces the tip surface 61a without passing through the tip surface 161a is larger than the width β of the tip surface 161a of the connecting sheet 161.

  In addition, the first circumferential sheet portion 54 located outside the second circumferential sheet portion 55 of the first sheet 51 in the radial direction of the second piston body 31 </ b> B is cut away from the front end surface 51 a of the first sheet 51. A notch 162 is provided.

  According to the fifth embodiment, the notch 141 is provided by communicating the inner passage 52 inside the first seat 51 with the annular passage 67 on the center side in the radial direction of the second piston body 31B of the second seat 61, A cutout 162 is provided in the first sheet 51. Thereby, the circumferential positioning of the disk valve 84 can be made unnecessary.

  Here, in the first to fifth embodiments, the plurality of second passages 42 are provided in the piston 12, but it is sufficient that at least one second passage 42 is provided.

  The embodiment described above includes a cylinder filled with a working fluid, a piston that is slidably inserted into the cylinder and defines the inside of the cylinder as one side chamber and another side chamber, and is connected to the piston. A piston rod extending to the outside of the cylinder; and a damping force generation mechanism that is provided on the piston and generates a damping force by controlling a flow of a working fluid. The damping force generation mechanism is provided on the piston. And a plurality of communication passages that connect the one-side chamber and the other-side chamber, and a plurality of the passages that are arranged on one surface of the piston along the circumferential direction of the piston, each projecting to surround an inner passage that communicates with the communication passage. A first sheet, and a portion spaced apart from the first sheet on the radial center side of the piston from the first sheet, and centered on the piston center outside the opening of the communication path An annular second seat to be ejected, and a disc valve seated on the first seat and the second seat, and the disc valve and the first seat or the second seat are provided between the first seat and the second seat. A notch for communicating the inner peripheral side of the two sheets with the other side chamber is provided. Therefore, since the working fluid can smoothly flow from the inner peripheral side of the second seat to the other side chamber when the disc valve is opened, an increase in the damping force characteristic can be suppressed in the high speed region of the piston speed.

  The second seat protrudes lower than the first seat, and the disc valve is disposed so as to overlap with the small-diameter disc that is seated on the second seat and has a larger diameter than the small-diameter disc. And a large-diameter disk seated on the first sheet, wherein the notch is provided in the small-diameter disk or the second sheet. As described above, a plurality of first sheets protruding so as to surround the opening of the first passage are provided side by side in the circumferential direction of the piston, and the opening of the second passage is located closer to the center side in the radial direction of the piston than these first sheets. An annular second sheet protruding so as to surround the second sheet is provided, and a notch is provided on the second sheet side. This eliminates the need for circumferential positioning of the disk valve.

  The small-diameter disk is composed of a plurality of disks, is seated on the second sheet, is provided with the notch on the outer peripheral side, and has a first opening penetrating in the thickness direction on the inner peripheral side. And a first communication disk having a second opening that covers the notch on the outer peripheral side and communicates with the first opening on the inner peripheral side, one of the one-side chamber and the other-side chamber on the outer peripheral side, and the first A second communication disk having a radial passage communicating with the second opening of the communication disk; and a notch disk provided on the opposite side of the first communication disk, from the communication path to the one side chamber and the other When the working fluid flows into any one of the side chambers, the first opening of the notch disk is closed, and when the working fluid flows from any one of the one side chamber and the other side chamber to the communication path, the notch And having a closing disc for communicating with said communication path of said first opening of click, the. As a result, when the piston moves to one side, the fixed orifice, which is the flow area of the gap between the notch and the second sheet, moves between the notch and the second sheet when the piston moves to the opposite side. The flow path area of the flow path for opening the closed disk is changed through the radial passage of the second communication disk, the second opening of the first communication disk, and the first opening of the notch disk in addition to the flow area of the gap. . Thus, the flow path area of the fixed orifice of the disc valve can be changed between the expansion stroke and the contraction stroke.

  Further, the blocking disk has a thickness smaller than that of the notch disk, the first communication disk, and the second communication disk. Thereby, the closing disk can be easily opened.

  The first seat includes a pair of radial seat portions extending in the radial direction of the piston, a first circumferential seat portion extending in the circumferential direction of the piston, and the piston more than the first circumferential seat portion. And a second circumferential sheet portion on the center side in the radial direction, wherein a groove is provided between the second circumferential sheet portion and the second sheet. Thus, since the groove is provided between the second circumferential seat portion and the second seat, the disc valve can be easily separated.

  The notch communicates the inside of the first sheet with the center side of the second sheet in the radial direction of the piston. This eliminates the need for circumferential positioning of the disk valve.

  The communication passage includes a plurality of first passages and at least one second passage which are provided in the piston and communicate with the one-side chamber and the other-side chamber, and the first seat includes the first seat The second sheet is provided so as to protrude so as to surround the opening of the corresponding one of the passages, and the second sheet is provided so as to surround the opening of the second path.

  In addition, the first sheet and the second sheet are separated over the entire circumference. Since the working fluid can flow more smoothly from the inner peripheral side of the second seat to the other side chamber when the disc valve is opened, the inclination of the damping force with respect to the piston speed in the valve characteristics can be further suppressed.

DESCRIPTION OF SYMBOLS 10 Shock absorber 11 Cylinder 12 Piston 13 Piston rod 19 1st chamber 20 2nd chamber 41 1st channel | path (communication channel)
41a Opening 42 Second passage (communication passage)
42a Opening 51 First seat 52 Inner passage 53 Radial seat portion 54 First circumferential seat portion 55 Second circumferential seat portion 61 Second seat 63 Groove 84 Disc valve 95 Small diameter disc 95A Small diameter disc (blocking disc)
95B Small-diameter disc (notched disc)
95Ba 1st opening 95C Small diameter disk (1st communication disk)
95Ca 2nd opening 95D Small diameter disk (2nd communication disk)
95 Da 3rd opening 95 Db Radial passage 96 Large diameter disk 97, 141 Notch 100 Damping force generating mechanism 171 Arc-shaped part

Claims (8)

A cylinder filled with a working fluid;
A piston that is slidably inserted into the cylinder and defines the inside of the cylinder into one side chamber and another side chamber;
A piston rod connected to the piston and extending to the outside of the cylinder;
A damping force generating mechanism that is provided in the piston and generates a damping force by controlling the flow of the working fluid;
With
The damping force generation mechanism is
A communication path provided in the piston for communicating the one-side chamber and the other-side chamber;
A plurality of first seats arranged side by side in the circumferential direction of the piston, each projecting so as to surround an inner passage communicating with the communication passage;
An annular second sheet that has a portion that is spaced apart from the first sheet on the center side in the radial direction of the piston relative to the first sheet, and that protrudes around the center of the piston outside the opening of the communication path; ,
A disc valve seated on the first seat and the second seat;
With
A shock absorber characterized in that a notch is provided between the disk valve and the first seat or the second seat so that the inner peripheral side of the second seat communicates with the other side chamber. . The second sheet protrudes lower than the first sheet;
The disc valve is
A small diameter disk seated on the second seat;
A large-diameter disk that has a larger diameter than the small-diameter disk and is placed on the small-diameter disk and is seated on the first seat,
The shock absorber according to claim 1, wherein the notch is provided in the small-diameter disk or the second sheet. The small diameter disk is composed of a plurality of disks,
A notch disk seated on the second sheet, the notch provided on the outer peripheral side and having a first opening penetrating in the thickness direction on the inner peripheral side;
A first communication disk having an outer peripheral side covering the notch and having a second opening communicating with the first opening on the inner peripheral side;
A second communication disk having a radial passage that communicates either one of the one-side chamber and the other-side chamber and the second opening of the first communication disk on an outer peripheral side;
The notch disc is provided on the opposite side of the first communication disc, and the first opening of the notch disc is formed when a working fluid flows from the communication path to one of the one side chamber and the other side chamber. A closing disk that closes and communicates the first opening of the notch disk with the communication path when a working fluid flows into the communication path from one of the one side chamber and the other side chamber;
The shock absorber according to claim 2, comprising:   4. The shock absorber according to claim 3, wherein the blocking disk is thinner than the notch disk, the first communication disk, and the second communication disk. 5. The first sheet is
A pair of radial seat portions extending in the radial direction of the piston;
A first circumferential sheet portion extending in a circumferential direction of the piston;
A second circumferential seat portion on the center side in the radial direction of the piston from the first circumferential seat portion;
Consists of
The shock absorber according to any one of claims 1 to 4, wherein a groove is provided between the second circumferential sheet portion and the second sheet.   The shock absorber according to claim 5, wherein the notch communicates the inside of the first sheet and the center side of the second sheet in the radial direction of the piston. The communication path includes a plurality of first paths and at least one second path that are provided in the piston and allow the one-side chamber and the other-side chamber to communicate with each other.
The first sheet is provided to protrude so as to surround an opening of a corresponding one of the first passages,
The shock absorber according to any one of claims 1 to 6, wherein the second sheet is provided so as to protrude from an opening of the second passage.   The shock absorber according to any one of claims 1 to 7, wherein the first sheet and the second sheet are spaced apart over the entire circumference.

Images