CN110998130B

CN110998130B - Buffer device

Info

Publication number: CN110998130B
Application number: CN201880051425.1A
Authority: CN
Inventors: 岛崎聪; 山下干郎; 松村定知; 吉田豊
Original assignee: Hitachi Astemo Ltd
Current assignee: Hitachi Astemo Ltd
Priority date: 2017-08-09
Filing date: 2018-08-03
Publication date: 2022-04-26
Anticipated expiration: 2038-08-03
Also published as: CN110998130A; JPWO2019031405A1; WO2019031405A1; DE112018004049T5; JP6921201B2

Abstract

The damping force generation mechanism provided in the damper includes: a valve main body (31) through which a passage (76) through which the working fluid flows passes penetrates the valve main body (31); a substantially circular outer seat (61) formed on the valve body (31) so as to protrude so as to surround an opening (77) of the passage (76); an inner seat formed to protrude inward of the outer seat (61); a disk (115) seated on the outer seat (61) and the inner seat. The outer seat (61) has a gradually decreasing width section (65) whose radial width gradually decreases toward the disk (115). The disk (115) has a portion that is radially opposed to the gradually decreasing width portion (65) when seated on the outer seat (61). The flow path area between the disk (115) and the gradually decreasing width section (65) is larger when the disk (115) and the gradually decreasing width section (65) are not opposed to each other, compared to when the disk (115) and the gradually decreasing width section (65) are opposed to each other in the radial direction.

Description

Buffer device

Technical Field

The present invention relates to a buffer.

The present application claims priority based on application No. 2017-154817 filed in japan on 8, 9, 2017, the contents of which are incorporated herein by reference.

Background

There is a damper in which a rate of increase in damping force with respect to increase in piston speed is made lower in a high speed region than in a middle speed region by separating a disc from an outer seat when the piston speed is in the middle speed region and separating the disc from an intermediate seat when the piston speed is in the high speed region (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-70658

Disclosure of Invention

Problems to be solved by the invention

There is a desire to reduce the rate of increase in the damping force with respect to increase in the piston speed.

The invention provides a damper capable of reducing the proportion of the rise of a damping force to the increase of a piston speed by a simple structure.

Means for solving the problems

According to one aspect of the present invention, a buffer includes: a cylinder in which a working fluid is sealed; a piston slidably inserted into the cylinder and dividing the interior of the cylinder into two chambers; a piston rod coupled to the piston and extending to the outside of the cylinder; a passage through which a working fluid flows by sliding of the piston; a damping force generating mechanism provided in the passage and configured to control a flow of the working fluid to generate a damping force; the damping force generation mechanism includes: a valve body, the passage penetrating the interior of the valve body; a substantially circular outer seat formed in the valve main body so as to protrude so as to surround an opening of the passage; an inner seat formed on the valve main body to protrude inward of the outer seat; a disk-shaped disk valve that is seated on the outer seat and the inner seat, and that separates from and seats against at least the outer seat by flexing of the outer periphery side; the outer seat has at least one of an inner circumferential side tapered portion whose inner circumferential side expands or an outer circumferential side tapered portion whose outer circumferential side contracts toward a seat surface on which the disc valve is seated. The disc valve includes at least one of an inner protrusion radially facing the inner tapered portion or an outer protrusion radially facing the outer tapered portion in a closed valve state seated on the outer seat. After the disc valve starts to open from the closed state, as the disc valve opens, a flow passage area formed between the radially opposed portions of the inner protruding portion and the inner circumferential tapered portion or between the radially opposed portions of the outer protruding portion and the outer circumferential tapered portion is smaller than a flow passage area formed by a gap between the disc valve and a distal end of the outer seat, and the flow passage area is larger than a flow passage area formed by a gap between the disc valve and a distal end of the outer seat.

Effects of the invention

According to the damper, the proportion of the rise of the damping force to the increase of the piston speed can be reduced with a simple configuration.

Drawings

Fig. 1 is a front view showing a part of a buffer according to a first embodiment of the present invention.

Fig. 2 is a sectional view showing a main part of a shock absorber according to a first embodiment of the present invention.

Fig. 3 is an enlarged cross-sectional view showing a main part of a first damping force generating mechanism of a shock absorber according to a first embodiment of the present invention.

Fig. 4 is a plan view showing a contact pad of a first damping force generating mechanism of a shock absorber according to a first embodiment of the present invention.

Fig. 5A is a diagram illustrating a state of the first damping force generating mechanism of the shock absorber according to the first embodiment of the present invention.

Fig. 5B is a diagram illustrating a state of the first damping force generating mechanism of the shock absorber according to the first embodiment of the present invention.

Fig. 5C is a diagram illustrating a state of the first damping force generating mechanism of the shock absorber according to the first embodiment of the present invention.

Fig. 6 is a characteristic diagram showing a relationship between a flow passage area and a valve opening height of the first damping force generating mechanism of the shock absorber according to the first embodiment of the present invention.

Fig. 7 is an enlarged cross-sectional view showing a main part of a modification 1 of the first damping force generating mechanism of the shock absorber according to the first embodiment of the present invention.

Fig. 8 is an enlarged cross-sectional view showing a main part of a modification 2 of the first damping force generating mechanism of the shock absorber according to the first embodiment of the present invention.

Fig. 9 is an enlarged cross-sectional view showing a main part of modification 3 of the first damping force generating mechanism of the shock absorber according to the first embodiment of the present invention.

Fig. 10 is an enlarged cross-sectional view showing a main part of a modification 4 of the first damping force generating mechanism of the shock absorber according to the first embodiment of the present invention.

Fig. 11 is an enlarged cross-sectional view showing a main part of a modification 5 of the first damping force generating mechanism of the shock absorber according to the first embodiment of the present invention.

Fig. 12 is an enlarged cross-sectional view showing a main part of a modification 6 of the first damping force generating mechanism of the shock absorber according to the first embodiment of the present invention.

Fig. 13 is an enlarged cross-sectional view showing a main part of a first damping force generating mechanism of a shock absorber according to a second embodiment of the present invention.

Detailed Description

[ first embodiment ]

A first embodiment of the present invention will be described below with reference to fig. 1 to 12.

The shock absorber 10 of the first embodiment is a fluid pressure shock absorber using liquid or gas as a working fluid. Specifically, the shock absorber 10 is a hydraulic shock absorber using oil as a working fluid. As shown in fig. 1, the shock absorber 10 includes a cylinder 11 in which a working fluid is sealed. Although not shown, the cylinder 11 has a bottomed cylindrical shape with one end side (upper side in fig. 1) opened and the other end side (lower side in fig. 1) closed. A piston 12 is slidably inserted into the cylinder 11.

A piston rod 13 is inserted into the cylinder 11. The piston 12 is coupled to one end side (lower side in fig. 1) of the piston rod 13 by a nut 14.

The other end side (upper side in fig. 1) of the piston rod 13 projects outward of the cylinder 11. The other end of the piston rod 13, one end of which is connected to the piston 12, is inserted through a rod guide 15 and an oil seal 16 attached to the opening of the cylinder 11 and projects outside the cylinder 11. The piston 12 divides the interior of the cylinder 11 into two chambers, a first chamber 19 between the free pistons 18 on the bottom 17 side (lower side in fig. 1) of the cylinder 11 and a second chamber 20 on the opening side (upper side in fig. 1) from which the piston rod 13 projects.

As shown in fig. 2, the piston rod 13 has a main shaft portion 25 and a mounting shaft portion 26, and the mounting shaft portion 26 is located at an end portion of the piston rod 13 in the cylinder 11 and is smaller in diameter than the main shaft portion 25.

Thus, an end face 27 extending in the direction orthogonal to the axis is formed at the end of the main shaft portion 25 on the side of the attachment shaft portion 26. A male screw 28 into which a female screw 30 of the nut 14 is screwed is formed in a predetermined range on the opposite side of the mounting shaft 26 from the main shaft 25.

The piston 12 includes an annular piston main body 31 (valve main body) and an annular belt-shaped sliding contact member 33 attached to an outer peripheral surface of the piston main body 31 and slidably contacting an inner peripheral surface of the cylinder 11. Thus, the piston 12 including the piston main body 31 and the sliding contact member 33 has an annular shape. The piston main body 31 is made of metal. The piston main body 31 is integrally molded by sintering. The sliding contact member 33 is made of synthetic resin. The center axes of the piston main body 31 and the piston 12 to which the sliding contact member 33 is integrally attached are made coincident with each other. Thus, the piston body 31 coincides with the axial direction, which is the direction along the center axis, coincides with the radial direction, which is the direction orthogonal to the center axis, and coincides with the circumferential direction, which is the direction around the center axis, of the piston 12.

An insertion hole 35 through which the attachment 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. A first passage hole 41 and a second passage hole 42, both extending in the axial direction of the piston main body 31, are formed in the piston main body 31 at positions outside the insertion hole 35 in the radial direction thereof.

The first passage hole 41 is disposed on the inner circumferential side in the radial direction of the piston main body 31 on the first chamber 19 side than on the second chamber 20 side. The second chamber 20 side of the second passage hole 42 is disposed on the radially inner peripheral side of the piston main body 31 with respect to the first chamber 19 side.

The piston main body 31 is provided with a plurality of first passage holes 41 (only one of which is shown in fig. 2 as a cross-sectional view). A plurality of second via holes 42 are also provided (only one is shown in fig. 2 as a cross-sectional view) similarly to the first via holes 41. The first passage holes 41 and the second passage holes 42 are alternately arranged in the circumferential direction of the piston main body 31.

An opening surface 52 is formed on the first chamber 19 side of the piston main body 31 to open the openings 51 of all the first passage holes 41 on the first chamber 19 side. An opening surface 54 is formed on the outer side of the opening surface 52 in the radial direction of the piston main body 31, to which the openings 53 on the first chamber 19 side of all the second passage holes 42 are opened.

The piston main body 31 has a first substantially circular outer seat 61 (outer seat) on the first chamber 19 side, which is formed to project from the opening surfaces 52, 54 in the axial direction of the piston main body 31 so as to surround all the openings 51 from the outside in the radial direction of the piston main body 31. The first outer seat 61 has an inner tapered surface 62, an outer tapered surface 63, and a front end surface 64. The radially inner side of the inner tapered surface 62 is larger in diameter (inner diameter is larger) toward the projecting tip side (toward the seat surface). The outer tapered surface 63 has a smaller diameter (reduced outer diameter) toward the radially outward projecting tip side (toward the seat surface). The distal end surface 64 is a flat surface extending in the orthogonal axis direction on the projecting distal end side. The protruding tip end side of the first outer holder 61 has these tapered

surfaces

62 and 63 and a tip end surface (seat surface) 64, and is a first gradually decreasing width portion 65 (gradually decreasing width portion) whose radial width gradually decreases toward the protruding tip end side. The opening surface 52 is disposed radially inward of the tapered surface 62. The opening surface 54 is disposed radially outward of the tapered surface 63.

The piston main body 31 is provided with a substantially circular first inner seat 71 (inner seat) on the first chamber 19 side. The first inner seat 71 is disposed radially inward of the first outer seat 61 with respect to the piston main body 31. The first inner seat 71 is formed to protrude in the axial direction of the piston main body 31 from the opening surface 52. In other words, the first inner seat 71 is formed in the piston main body 31 so as to protrude from the opening surface 52 inside the first outer seat 61. The first inner seat 71 has a tapered surface 72 and a front end surface 73. The tapered surface 72 has a smaller diameter toward the radially outward projecting tip side. The distal end surface 73 is a flat surface extending in the orthogonal axis direction on the projecting distal end side. The inner peripheral side of the first inner holder 71 is formed as an insertion hole 35. The outer diameter of the distal end surface 73 is substantially equal to the outer diameter of the end surface 27 of the piston rod 13.

The first annular passage 75 is formed between the first outer seat 61 and the first inner seat 71, that is, between the opening surface 52 and the

tapered surfaces

62 and 72, and communicates all of the first passage holes 41. All of the first passage holes 41 and the first annular passages 75 form first passages 76 (passages) that axially penetrate the piston 12. In the first passage 76, the working fluid flows by the sliding of the piston 12 relative to the cylinder 11.

A first opening 77 (opening) on the first chamber 19 side of the first passage 76 is formed between the front end surface 64 of the first outer holder 61 and the front end surface 73 of the first inner holder 71. Thus, the substantially circular first outer seat 61 is formed on the piston main body 31 so as to protrude from the opening surface 52 so as to surround the first opening 77 of the first passage 76. The first opening 77 of the first passage 76 is disposed between the first outer holder 61 and the first inner holder 71.

In the piston main body 31, an opening surface 82 is formed on the second chamber 20 side, on which the openings 81 on the second chamber 20 side of all the second passage holes 42 are opened. An opening surface 84 is formed on the radially outer side of the opening surface 82 with respect to the piston main body 31, and the openings 83 of all the first passage holes 41 on the second chamber 20 side are opened.

The piston main body 31 has a substantially circular second outer seat 91 on the second chamber 20 side. The second outer seat 91 is formed to surround the entire opening 81 from the outside in the radial direction of the piston main body 31. The second outer seat 91 is formed to protrude in the axial direction of the piston main body 31 from the opening surfaces 82 and 84. The second outer seat 91 has a tapered surface 92, a tapered surface 93, and a front end surface 94. The tapered surface 92 has a larger diameter at the radially inward projecting tip side. The tapered surface 93 has a smaller diameter toward the radially outward projecting tip side. The distal end surface 94 is a flat surface extending in the orthogonal axis direction on the projecting distal end side. The projecting tip of the second outer holder 91 has the tapered surfaces 92 and 93 and the tip surface 94, and is a second gradually decreasing width portion 95 whose radial width gradually decreases toward the projecting tip. The opening surface 82 is disposed radially inward of the tapered surface 92. The opening surface 84 is disposed radially outward of the tapered surface 93.

The piston main body 31 is provided with a substantially circular second inner seat 101 on the second chamber 20 side. The second inner seat 101 is disposed radially inward of the second outer seat 91 with respect to the piston main body 31. The second inner seat 101 is formed to protrude in the axial direction of the piston main body 31 from the opening surface 82. The opening surface 82 and all the openings 81 are disposed between the second outer holder 91 and the second inner holder 101. The second inner seat 101 has a tapered surface 102 and a front end surface 103. The tapered surface 102 has a smaller diameter toward the radially outward projecting tip side. The distal end surface 103 is a flat surface extending in the orthogonal axis direction on the protruding distal end side. The inner peripheral side of the second inner holder 101 is formed as an insertion hole 35. The outer diameter of the distal end surface 103 is substantially equal to the outer diameter of the end surface 27 of the piston rod 13.

The second annular passage 105 is formed between the second outer seat 91 and the second inner seat 101, that is, between the opening surface 82 and the tapered surface 92 and the tapered surface 102, and is annular so as to communicate with all of the second passage holes 42. All of the second passage holes 42 and the second annular passage 105 form a second passage 106 that axially penetrates the piston 12. In the middle, the working fluid flows through the second passage 106 by sliding of the piston 12 relative to the cylinder 11.

A second opening 107 on the second chamber 20 side of the second passage 106 is formed between the front end surface 94 of the second outer holder 91 and the front end surface 103 of the second inner holder 101. Thus, the second outer seat 91 having a substantially circular shape is formed on the piston main body 31 so as to protrude from the opening surface 82 so as to surround the second opening 107 of the second passage 106. The second opening 107 of the second passage 106 is disposed between the second outer holder 91 and the second inner holder 101.

The piston body 31 has a shape without distinction between the front and the back. Therefore, the piston main body 31 is configured as described above even when attached to the piston rod 13 in the forward and reverse directions.

On the end surface 27 of the main shaft portion 25 of the piston rod 13, a single annular restricting member 111, two small-diameter disks 112, a single large-diameter disk 113, a single abutting disk 114, the piston 12, a single abutting disk 115 (disk), two large-diameter disks 116, a single intermediate-diameter disk 117, a single intermediate-diameter disk 118, two small-diameter disks 119, and a single restricting member 120, which are all made of metal, are stacked in this order with the mounting shaft portion 26 fitted inside. In this state, the nut 14 is screwed to the female screw 30 on the male screw 28 protruding from the regulating member 120 of the attachment shaft portion 26.

By fastening the outer thread 28 of the nut 14, the one regulating member 111, the two small-diameter disks 112, the one large-diameter disk 113, the one abutment disk 114, the piston 12, the one abutment disk 115, the two large-diameter disks 116, the one intermediate-diameter disk 117, the one intermediate-diameter disk 118, the two small-diameter disks 119, and the one regulating member 120 are all laminated while being regulated in radial movement on the mounting shaft portion 26, and are sandwiched between the end face 27 of the piston rod 13 and the nut 14 in the laminated state. Thus, they are fixed at least to the inner peripheral side so as not to be movable in the axial direction with respect to the piston rod 13. As a result, the large diameter disc 113, the contact disc 114, the contact disc 115, the two large diameter discs 116, and the

intermediate diameter discs

117, 118 are clamped so as to be immovable in the axial direction with respect to the piston rod 13 only on the inner peripheral side.

The outer diameter of the restriction member 111 is larger than the outer diameter of the end surface 27 and the outer diameter of the distal end surface 103. The small-diameter disc 112 is flat and has the same outer diameter as the end surface 27. The large-diameter disc 113 is flat, has an outer diameter larger than that of the small-diameter disc 112, and is substantially equal to the outer diameter of the front end surface 94 of the second outer seat 91.

The contact disk 114 is flat and has the same outer diameter as the large diameter disk 113. The contact disc 114 is in contact with and seated on the front end surface 94 of the second outer seat 91 and the front end surface 103 of the second inner seat 101. The abutting disk 114 and the large diameter disk 113 constitute a disk valve 127. The disc valve 127 is axially clamped on the inner peripheral side by the small diameter disc 112 and the second inner seat 101, and a portion radially outward of the small diameter disc 112 is deformed so as to be separated from the piston main body 31 and separated from the distal end surface 94 of the second outer seat 91.

As shown in fig. 3, the contact disc 115 includes a base plate portion 131, an inner protruding plate portion 132, a front end plate portion 133, an outer protruding plate portion 134, and an outer end plate portion 135. The base plate portion 131 expands in the radial direction. The inner protruding plate portion 132 protrudes from the outer peripheral edge portion of the substrate portion 131 toward one side in the plate thickness direction. The distal end plate 133 extends radially outward from an end edge portion of the inner projecting plate 132 opposite to the base plate 131. The outer protruding plate portion 134 protrudes from the outer peripheral edge portion of the front plate portion 133 in the same direction as the protruding direction of the inner protruding plate portion 132 with respect to the front plate portion 133. The outer end plate 135 extends radially outward from an end edge of the outer protruding plate 134 opposite to the front end plate 133.

The base plate portion 131 is an annular flat plate extending radially outward from the inner end position of the contact pad 115. The outer end plate portion 135 is an annular flat plate located at the outer end in the radial direction of the contact disc 115. These substrate portion 131 and outer end plate portion 135 are disposed on the same plane. The inner protruding flange portion 132 has a tapered tubular shape with a larger diameter as it is axially separated from the base plate portion 131. The outer side flange portion 134 has a tapered tubular shape with a diameter that decreases as it moves away from the outer end plate portion 135 in the axial direction. In other words, the inner projecting plate portion 132 is expanded in diameter and projects from the base plate portion 131 and the outer end plate portion 135. The outer side protruding plate portion 134 is reduced in diameter from the base plate portion 131 and the outer end plate portion 135 and protrudes. The front end plate 133 is an annular flat plate and is disposed parallel to the base plate 131 and the outer end plate 135.

The inner side projecting plate portion 132, the front end plate portion 133, and the outer side projecting plate portion 134 constitute a projecting portion 136 projecting in the axial direction from the base plate portion 131 and the outer end plate portion 135 located on both sides in the radial direction thereof. As shown in fig. 4, the convex portion 136 (inner protruding portion) has an annular shape.

A plurality of, specifically, two notch portions 138 are formed at equal intervals in the circumferential direction on the contact disk 115. The notch 138 penetrates in the plate thickness direction, and a portion of the distal end plate 133 on the side of the inner projecting plate 132 passes through the outer projecting plate 134 and the outer end plate 135 to pass radially outward.

The contact disk 115 is formed by press forming a flat plate-like metal plate having a constant thickness. As a result, as shown in fig. 3, the inner projecting plate portion 132, the front end plate portion 133, and the outer projecting plate portion 134, which form the projecting portion 136 of the contact disc 115, have a thickness substantially equal to the thickness of the base plate portion 131 and the outer end plate portion 135.

The outer diameter of the portion of the abutment disc 115 other than the notch portion 138 of the outer end plate portion 135 is equal to the outer diameter of the front end surface 64 of the first outer seat 61. Further, the outer diameter of the end of the outer end plate portion 135 side of the outer peripheral surface 140 of the outer projecting plate portion 134 of the contact disc 115 is slightly smaller than the inner diameter of the front end surface 64 of the first outer seat 61. The outer peripheral surface 140 of the outer flange 134 is tapered in the same manner as the tapered surface 62 of the first gradually decreasing width portion 65 of the first outer seat 61.

Further, one of the outer peripheral surface 140 and the tapered surface 62 may be made larger in taper than the other, or conversely, the other may be made larger in taper than the one.

The abutting disc 115 is in a state in which the protruding portions 136 protrude from the base plate portion 131 and the outer end plate portion 135 located on both sides in the radial direction toward the piston 12, the outer end plate portion 135 abuts against and is seated on the front end surface 64 of the first outer seat 61 with the piston 12 side facing surface 141 facing each other, and the base plate portion 131 abuts against and is seated on the front end surface 73 of the first inner seat 71 shown in fig. 2.

In this state, as shown in fig. 3, the front end surface 142 of the front end plate portion 133 of the contact disc 115 is positioned closer to the opening surface 52 than the front end surface 64 of the first outer holder 61. The notch 138 of the contact disc 115 forms a fixed orifice that allows the first passage 76 to communicate with the first chamber 19 even when the contact disc 115 is seated on the front end surface 64 of the first outer seat 61 on the facing surface 141 of the outer end plate portion 135. Instead of forming the notch 138 in the contact disk 115, a fixed orifice may be formed by providing a notch radially penetrating the first outer seat 61 from the front end surface 64 so as to be recessed. That is, the contact disk 115 forms an inner protruding portion by the front end surface 142, which is a thick wall portion protruding toward the piston 12 side surface as the valve main body.

In a state where the contact disc 115 is seated on the front end surface 64 of the first outer seat 61 of the piston main body 31 on the facing surface 141 of the outer end plate portion 135 (the valve lift amount is 0), the annular protrusion 136 enters the radial inner side of the annular first width gradually decreasing portion 65 of the first outer seat 61.

At this time, the tapered surface 62 of the first width gradually decreasing portion 65 inclined in an equal taper shape and the outer peripheral surface 140 of the outer projecting plate portion 134 overlap at a position in the axial direction and are opposed to each other with some gap in the radial direction.

In other words, in a state where the contact disc 115 is seated on the distal end surface 64 of the first outer seat 61 in the outer end plate portion 135, the annular convex portion 136 and the annular first gradually decreasing width portion 65 of the piston main body 31 overlap each other in the axial direction and radially face each other. The first gradually decreasing width portion 65 of the first outer seat 61 gradually decreases in radial width toward the abutment disk 115.

As shown in fig. 3, the large-diameter disk 116 is flat and has an outer diameter equal to that of a portion other than the notch 138 of the outer end plate portion 135 of the abutting disk 115. The intermediate diameter disc 117 is a flat plate, and has a smaller outer diameter than the large diameter disc 116. As shown in fig. 2, the intermediate diameter disk 118 is a flat plate, and has an outer diameter smaller than that of the intermediate diameter disk 117. The small diameter disc 119 is flat, has an outer diameter smaller than that of the intermediate diameter disc 118, and is substantially equal to the outer diameter of the front end surface 73 of the first inner seat 71. The small diameter disc 119 is a member shared with the small diameter disc 112. The restriction member 120 has an outer diameter larger than that of the small diameter disc 119. The regulating member 120 is a member common to the regulating member 111.

The abutment disc 115, the large diameter disc 116, the intermediate diameter disc 117, and the intermediate diameter disc 118 constitute a disc valve 144. The disc valve 144 is axially clamped on the inner peripheral side by the small diameter disc 119 and the first inner seat 71, and a portion outside the small diameter disc 119 is deformed so as to be apart from the front end surface 64 of the first outer seat 61.

The disc valve 144, and the first outer seat 61 and the first inner seat 71 on which the disc valve is seated, constitute a first damping force generating mechanism 145 (damping force generating mechanism) provided in the first passage 76 to control the flow of the working fluid and generate a damping force. The first damping force generation mechanism 145 controls the damping force by controlling the flow path area (hereinafter, simply referred to as the flow path area) that is the smallest in the first passage 76. The flow passage area is an area of a gap between the first outer seat 61 and the disc valve 144. Further, the opening 53 of the second passage 106 is disposed radially outward of the disc valve 144, and the second passage 106 is not closed by the disc valve 144.

The disk valve 127 and the second outer seat 91 and the second inner seat 101 on which the disk valve is seated constitute a second damping force generation mechanism 148 provided in the second passage 106 to control the flow of the working fluid and generate a damping force. The second damping force generation mechanism 148 controls the flow passage area of the second passage 106 to control the damping force. The flow passage area is an area of a gap between the second outer seat 91 and the disc valve 127. Further, the opening 83 of the first passage 76 is disposed radially outward of the disc valve 127, and the first passage 76 is not closed by the disc valve 127.

The rigidity of the piston main body 31, the regulating member 111, and the regulating member 120 is higher than the rigidity of each of the large-diameter disc 113, the contact disc 114, the contact disc 115, the large-diameter disc 116, the intermediate-diameter disc 117, and the intermediate-diameter disc 118. The regulating member 111 suppresses further deformation of the disk valve 127 in a state where the deformed disk valve 127 is in contact with. The regulating member 120 suppresses further deformation of the disk valve 144 in a state where the deformed disk valve 144 abuts.

In the shock absorber 10, in the extension stroke in which the piston rod 13 moves to the extension side with respect to the cylinder 11, the pressure of the second chamber 20 is higher than the pressure of the first chamber 19 by the piston 12 moving integrally with the piston rod 13. Thereby, the working fluid in the second chamber 20 is introduced from the opening portions 83, which are always open, into the plurality of first passage holes 41 of the first passage 76. The working fluid introduced from the opening 83 flows out from the opening 51 to the first annular passage 75, merges, and acts on the disk valve 144 closing the first opening 77.

At this time, if the movement speed of the piston 12, that is, the piston speed, is low, the disc valve 144 of the first damping force generation mechanism 145 is not separated from the first outer seat 61 by the working fluid in the first passage 76. That is, as shown in fig. 3, the contact state between the facing surface 141 of the outer end plate portion 135 of the contact tray 115 and the front end surface 64 of the first outer holder 61 is maintained. Then, the working fluid in the second chamber 20 flows from the first passage 76 to the first chamber 19 through the cutout portion 138, which is a fixed orifice, of the contact disc 115 of the disc valve 144. Accordingly, since the flow passage area of the first passage 76 is constant, a damping force of the orifice characteristic (the damping force is substantially proportional to the square of the piston speed) is generated.

When the piston speed increases, the working fluid in the first passage 76 separates the disc valve 144 including the contact disc 115 of the first damping force generation mechanism 145 from the first outer seat 61.

At this time, a damping force of a valve characteristic (damping force is substantially proportional to the piston speed) corresponding to the flow passage area between the disc valve 144, which is the flow passage area of the first passage 76, and the first outer seat 61 is generated.

The disc valve 144 is separated from the first outside seat 61 by a differential pressure generated between the upstream side and the downstream side thereof. The valve opening height, which is the distance between the facing surface 141 of the outer end plate portion 135 of the contact disc 115 and the front end surface 64 of the first outer seat 61, is proportional to the differential pressure.

In the first embodiment, the contact disc 115 is provided with the convex portion 136, the convex portion 136 includes the outer h projecting plate portion 134, and the outer projecting plate portion 134 is opposed to the first gradually decreasing width portion 65 of the first outer seat 61 with a slight gap in the radial direction in a small state including a valve-closed state in which the valve-opening height is 0. Thus, the ratio of the increase in the flow passage area to the increase in the piston speed changes between the low speed region and the high speed region, and the ratio of the increase in the damping force to the increase in the piston speed changes between the low speed region and the high speed region.

The ratio of increase in the flow passage area to increase in the piston speed and the ratio of increase in the damping force to increase in the piston speed in the first embodiment will be described in more detail with reference to fig. 5A to 6. Fig. 5A to 5C are views for explaining the state of the first damping force generating mechanism of the shock absorber according to the first embodiment. Fig. 5A is a closed valve state in which the first width gradually decreasing portion 65 contacts the contact disc 115 and the valve-opening height is 0. FIG. 5B shows the first gradually decreasing width portion 65 being spaced apart from the contact pad 115 by a predetermined distance h_bA diagram of the state of (1). FIG. 5C shows the first gradually decreasing width portion 65 being spaced apart from the contact pad 115 by a predetermined distance h_cA diagram of the state of (1). As described above, the distance between the contact disc 115 and the first gradually decreasing width portion 65 indicates the valve opening height.

Fig. 6 is a characteristic diagram showing a relationship between the flow path area and the valve opening height. In fig. 6, the horizontal axis h represents the valve opening height. The vertical axis S represents the flow path area. The point a shown in fig. 6 corresponds to the state of fig. 5A. The point B shown in fig. 6 corresponds to the state of fig. 5B. The point C shown in fig. 6 corresponds to the state of fig. 5C.

That is, fig. 5A shows a closed state in which the valve opening height is 0. In the sections a to B from the valve-closed state to the predetermined height shown in fig. 5B, as shown in fig. 6, the flow path area S_abProportionally increases with respect to the increase of the valve opening height h. The sections a to b include ranges in which the contact disc 115 and the first gradually decreasing width portion 65 having the inner tapered surface 62 (having an enlarged inner diameter) overlap each other in the valve opening height direction and radially face each other. In the sections B to C from the predetermined height shown in FIG. 5B to the further increase of the valve opening height h as shown in FIG. 5C, the flow path area S is as shown in FIG. 6_bcThe valve opening height h is increased in proportion to a ratio higher than the intervals a to b. Is formed byThe flow path area ratio S of the gap formed by the first outer seat 61, which is the tip of the outer seat, and the contact disk 115, which is the disk valve_abAfter that, the sections a to b continue this state. Then, the flow path area S between the sections b to c_bcIs larger than a gap formed by the first outer seat 61 as the tip of the outer seat and the abutting disk 115 as the disk valve. That is, the flow path area of the gap formed between the contact pad 115 and the distal end of the first outer holder 61 is smaller than the flow path area of the gap.

As shown in fig. 5A, the radius of the inner peripheral edge of the front end surface 64 of the first outer holder 61 is defined as r₁R represents the radius of the outer peripheral edge of the front end surface 142 of the contact disk 115₂The height from the facing surface 141 of the contact tray 115 to the distal end surface 142 is H. As shown in fig. 5B, the inclination angle of the tapered surface 62 of the first outer holder 61 with respect to the center axis is θ₁The inclination angle of the outer peripheral surface 140 of the abutment disk 115 with respect to the central axis is set to θ₂The height of the sections a to b from the facing surface 141 of the contact plate 115 to the front end surface 64 of the first outer holder 61 is h_b. As shown in fig. 5C, the height of the sections b to C from the facing surface 141 of the contact plate 115 to the front end surface 64 of the first outer holder 61 is h_c。

The flow path area S of the sections a to b_abCan be obtained by the following formula (1).

S_ab≒2πr₁ h_b cosθ₂···(1)

Here, 0 < h_b＜H+h_b cos²θ₂。

The flow path area S of the sections b to c_bcCan be obtained by the following formula (2).

S_bc≒2πr₁sqrt{(r₁－r₂)²+(h_c－h_b)²}···(2)

Here, h_b＝H+h_b cos²θ₂When S is present_ab＝S_bc。

With the above, if the valve opening height exceeds S_ab＝S_bcOpen valve height h of_bWhen the valve is in the closed state, the flow path area increases more than the valve opening height_ab＝S_bcOpen valve height h of_bThe increasing ratio of the interval of (a). Thus, if the valve opening height exceeds S_ab＝S_bcOpen valve height h of_bWhen the valve is closed, the pressure reaches S_ab＝S_bcOpen valve height h of_bThe rate of increase of the damping force of the first damping force generation mechanism 145 to increase of the piston speed can be suppressed as compared with the section(s) of (a). As described above, the valve is closed to S_ab＝S_bcOpen valve height h of_bThe sections a to b include ranges in which the contact disc 115 and the first gradually decreasing width portion 65 overlap each other in the valve opening height direction and radially face each other.

Thus, the rate of increase in the damping force with respect to the increase in the piston speed is lower in the speed range in which the piston speed is high in the sections b to c than in the speed range in which the piston speed is low in the sections a to b.

Flow path area S_bcThe flow passage area between the contact disc 115 and the first gradually-decreasing width portion 65 when the contact disc 115 does not radially face the first gradually-decreasing width portion 65 is larger than the flow passage area S, which is the flow passage area between the contact disc 115 and the first gradually-decreasing width portion 65 when the contact disc 115 radially faces the first gradually-decreasing width portion 65_ab. In other words, the flow passage area of the first passage 76 determined by the distance relationship between the contact disc 115 and the first gradually-decreasing width portion 65 when not radially opposed to the first gradually-decreasing width portion 65 is larger than the flow passage area of the first passage 76 determined by the distance relationship between the contact disc 115 and the first gradually-decreasing width portion 65 when radially opposed to the first gradually-decreasing width portion 65. In other words, when the piston speed enters the high speed region from the low speed region and the valve opening height of the contact disc 115 exceeds a predetermined value, the ratio of the increase in the flow passage area to the increase in the valve opening height is larger than before, and the ratio of the increase in the damping force to the increase in the piston speed is suppressed to be lower than before.

In a contraction stroke in which the piston rod 13 moves toward the contraction side with respect to the cylinder 11 shown in fig. 2, the pressure of the first chamber 19 is higher than the pressure of the second chamber 20 by the piston 12 moving integrally with the piston rod 13. Thereby, the working fluid in the first chamber 19 is introduced from the opening portions 53, which are always open, into the plurality of second passage holes 42 of the second passage 106. The working fluid introduced from the opening 53 flows out from the opening 81 to the second annular passage 105, merges, and acts on the disk valve 127 of the second damping force generation mechanism 148 that closes the second opening 107.

Then, the working fluid in the second passage 106 opens the disc valve 127 away from the second outer seat 91. Thereby, the working fluid flows from the first chamber 19 to the second chamber 20 through the second passage 106 with a flow path area corresponding to the valve opening amount of the disk valve 127 and the second outer seat 91. Therefore, a damping force of the valve characteristic is generated.

Patent document 1 describes the following damper: when the piston speed is in the middle speed range, the disk is separated from the outer seat, and when the piston speed is in the high speed range, the disk is separated from the middle seat, so that the ratio of the rise of the damping force to the increase of the piston speed is lower in the high speed range than in the middle speed range. In this shock absorber, since the working fluid flows out from between the intermediate seat and the disc, which have a smaller diameter than the outer seat, in a high speed region of the piston speed, the flow passage area may not be sufficiently enlarged, and the rate of increase in the damping force with respect to the increase in the piston speed may not be sufficiently reduced.

In contrast, in the first damping force generating mechanism 145 of the shock absorber 10 according to the first embodiment, the first width gradually decreasing portion 65 of the first outer seat 61 is opposed to the convex portion 136 in the radial direction in a state where the contact pad 115 is in contact with the first outer seat 61. Thus, the flow passage area between the contact disc 115 and the first gradually-decreasing width portion 65 when not radially opposed to the first gradually-decreasing width portion 65 is increased as compared with the flow passage area between the contact disc 115 and the first gradually-decreasing width portion 65 when radially opposed to the first gradually-decreasing width portion 65, and the ratio of the rise of the damping force to the increase of the piston speed is made lower in the high speed region than in the medium speed region of the piston speed. Accordingly, the working fluid flows out from between the first outer seat 61 and the contact disc 115 even in the high speed region of the piston speed, as in the medium speed region of the piston speed, and therefore the flow passage area can be sufficiently enlarged, and the ratio of the rise of the damping force to the increase of the piston speed can be sufficiently reduced.

Further, the increase in the flow passage area in the initial stage of opening the valve of the first damping force generation mechanism 145 can be smoothed, and the generation of sound due to a rapid pressure change can be suppressed.

Further, since the convex portion 136 may be provided so as to radially face the first gradually decreasing width portion 65 in a state where the first outer seat 61 is in contact with the contact disc 115 and so as not to radially face the first gradually decreasing width portion 65 when the first outer seat 61 is separated by more than a predetermined amount, the ratio of the rise of the damping force to the increase of the piston speed can be made lower in the high speed region than in the middle speed region of the piston speed with a simple structure.

In addition, on the abutment disk 115 formed by press forming, a convex portion 136 is formed at the time of press forming. Therefore, an increase in the number of components can be suppressed, and an increase in cost can be suppressed.

In addition, although the convex portion 136 is formed in the contact disc 115 as described above, the contact disc 115 may be configured by a main disc 151 made of a flat plate and a diametrically opposed disc 152 made of a flat plate as in modification 1 shown in fig. 7. The main body disk 151 has an opposing surface 141 that is seated on the front end surface 64 of the first outer seat 61. The radially opposed disk 152 has an outer peripheral surface 140 and a distal end surface 142 which are arranged radially inward of the first outer seat 61 in a state where the main body disk 151 is seated on the distal end surface 64 of the first outer seat 61 on the opposed surface 141, and which are radially opposed to each other so as to overlap the first gradually decreasing width portion 65 in the axial direction.

As described above, instead of forming the convex portion 136 of the contact pad 115 with the inner projecting plate portion 132, the front end plate portion 133, and the outer projecting plate portion 134 having the same thickness as the base plate portion 131 and the outer end plate portion 135, the contact pad 115 may be made of, for example, a synthetic resin, as in modification 2 shown in fig. 8, so that a thick portion 155 having a thickness larger than that of the base plate portion 131 and the outer end plate portion 135 is formed between the base plate portion 131 and the outer end plate portion 135, and the convex portion 136 projecting from the base plate portion 131 and the outer end plate portion 135 may be formed by the thick portion 155. In this case, the base plate portion 131, the outer end plate portion 135, and the convex portion 136 can be formed by integral molding of resin.

As in modification 3 shown in fig. 9, the contact pad 115 may be configured by a pad main body 161 made of a flat metal plate and another member 162 made of synthetic resin provided on the outer peripheral side of the pad main body 161. The other member 162 has: a main portion 163 which is formed with a convex portion 136 having an outer peripheral surface 140 and a front end surface 142 and an opposite surface 141 and is in close contact with the disc main body 161; a covering portion 164 which is in close contact with the outer peripheral surface of the disc main body 161; and a mounting portion 165 closely contacting the disc main body 161 on the side opposite to the main portion 163. The covering portion 164 connects the outer peripheral edge of the main portion 163 and the outer peripheral edge of the mounting portion 165. In this case, the following manufacturing can be performed: the disc main body 161 is provided in a mold in which a cavity having the shape of the other member 162 is formed, and the synthetic resin material is poured into the cavity, and the other member 162 is formed on the outer peripheral portion of the disc main body 161.

As in modification 4 shown in fig. 10, the contact disk 115 may be formed by bonding a protrusion 136 as another member having an outer peripheral surface 140 and a distal end surface 142 to a disk main body 168 formed of a flat plate and forming the facing surface 141. In this case, the disc main body 168 may be made of metal, and the projection 136 may be made of synthetic resin. In this case, the following production can be performed: the disc main body 168 is provided in a mold in which a cavity having the shape of the convex portion 136 is formed, and the synthetic resin material is poured into the cavity, thereby forming the convex portion 136 in the disc main body 168.

In addition, although the outer peripheral surface 140 of the convex portion 136 of the contact disc 115 is tapered to be equal to the tapered surface 62 of the first outer seat 61 and opposed to each other with a slight gap in the radial direction as described above, the tapered surface 62 of the first outer seat 61 may be made larger than the tapered surface 140 of the convex portion 136 as in modification 5 shown in fig. 11, and the tapered surface 62 may be brought into contact with the end portion on the distal end surface 142 side of the outer peripheral surface 140. In contrast, as in modification 6 shown in fig. 12, the taper of the tapered surface 62 of the first outer holder 61 may be made smaller than the taper of the outer peripheral surface 140 of the projection 136, and the end portion of the tapered surface 62 on the distal end surface 64 side may be brought into contact with the outer peripheral surface 140.

Although not shown, in modifications 1 to 6, the fixed orifice is also configured by providing the contact pad 115 with a cutout 138 or by providing the first outer seat 61 with a cutout that penetrates in the radial direction so as to be recessed from the front end surface 64.

[ second embodiment ]

Next, a second embodiment will be described centering on a part different from the first embodiment, mainly with reference to fig. 13. The same reference numerals and the same names are used for the same portions as those in the first embodiment.

As shown in fig. 13, in the second embodiment, the abutment disk 115A is partially different from the abutment disk 115 of the first embodiment. The contact pad 115A includes a base plate portion 131A and a protruding plate portion 171 (protruding portion, outer protruding portion). The base plate portion 131A extends radially outward from the radially inner end position of the contact pad 115A. The protruding plate portion 171 protrudes from the outer peripheral edge of the substrate portion 131A toward one side in the plate thickness direction. The protruding plate portion 171 is located at the outer end position in the radial direction of the abutting disc 115A. That is, the protruding plate portion 171 is formed with an outer protruding portion by being bent toward the valve main body side. Further, the protruding plate portion may be formed inside the first outer holder 61 to form an inner protruding portion.

The substrate portion 131A is a disc-shaped flat plate. The protruding plate portion 171 has a tapered cylindrical shape with a larger diameter as it is axially separated from the base plate portion 131A. In other words, the protruding plate portion 171 is expanded in diameter and protrudes from the base plate portion 131A. The contact pad 115A has a notch 138A penetrating in the plate thickness direction and passing through the protruding plate 171 side of the base plate 131A to the outside in the radial direction through the protruding plate 171. The contact disk 115A is formed by press forming a flat plate-like metal plate having a constant thickness into the above-described shape. Thus, the base plate portion 131A and the protruding plate portion 171 of the contact pad 115A have the same thickness.

The outer diameter of the base plate portion 131A of the abutment disk 115A is substantially equal to the outer diameter of the front end surface 64 of the first outer holder 61. The inner peripheral surface 172 of the protruding plate portion 171 is tapered in the same manner as the radially outer tapered surface 63 of the first gradually decreasing width portion 65 of the first outer holder 61. The contact disc 115A is in a state in which the projecting plate portion 171 projects from the base plate portion 131A located radially inward toward the piston 12 side, and the base plate portion 131A is seated on the front end surface 64 of the first outer seat 61 and the front end surface 73 of the first inner seat 71 with the piston 12 side facing surface 141A (see fig. 2).

In this state, the tip end portion of the protruding plate portion 171 of the contact pad 115A is positioned closer to the opening surface 52 than the tip end surface 64 of the first outer holder 61. The notch 138A of the contact disc 115A constitutes a fixed orifice that allows the first passage 76 to communicate with the first chamber 19 even in a state where the contact disc 115A is seated on the front end surface 64 of the first outer seat 61. Further, the first outer seat 61 may be provided with a notch portion recessed from the front end surface 64 and penetrating in the radial direction to constitute a fixed orifice.

In the contact disc 115A, the annular projecting plate portion 171 is inserted radially inward into the annular first width gradually decreasing portion 65 of the first outer seat 61 in a state where the base plate portion 131A is seated on the front end surface 64 of the first outer seat 61 of the piston main body 31. At this time, the tapered surface 63 of the first width gradually decreasing portion 65 inclined in the same taper shape and the inner peripheral surface 172 of the protruding plate portion 171 overlap each other at an axial position and are opposed to each other with a slight gap in the radial direction.

In other words, in the contact disc 115A, in a state where the base plate portion 131A is seated on the distal end surface 64 of the first outer seat 61, the annular projecting plate portion 171 and the annular first gradually decreasing width portion 65 of the piston main body 31 overlap in the axial direction and radially face each other. The flow passage area of the first passage 76 in the protruding plate portion 171, which is determined by the distance relationship between the first gradually decreasing width portions 65 and the contact disc 115A when not radially opposed to the first gradually decreasing width portions 65, is larger than the flow passage area of the first passage 76 in the protruding plate portion 171, which is determined by the distance relationship between the first gradually decreasing width portions 65 and the contact disc 115A when radially opposed to the first gradually decreasing width portions 65.

In the second embodiment, the contact disc 115A, the large diameter disc 116, the intermediate diameter disc 117, and the intermediate diameter disc 118 (see fig. 2) constitute a disc valve 144A. The disc valve 144A, and the first outer seat 61 and the first inner seat 71 (see fig. 2) on which the disc valve is seated, constitute a first damping force generating mechanism 145A (damping force generating mechanism).

During the extension stroke, the working fluid in the second chamber 20 (see fig. 2) acts on the disc valve 144A from the first passage 76. At this time, if the piston speed, which is the moving speed of the piston 12, is low, the working fluid in the first passage 76 flows into the first chamber 19 through the notch 138A, which is a fixed orifice, of the contact disc 115A without separating the disc valve 144A of the first damping force generating mechanism 145A from the first outer seat 61, and generates a damping force of the orifice characteristic.

In a speed region where the piston speed is higher than this, the working fluid in the first passage 76 causes the disc valve 144A of the first damping force generation mechanism 145A to move away from the first outer seat 61. The contact disc 115A of the disc valve 144A is provided with a protruding plate portion 171 that faces the first gradually decreasing width portion 65 of the first outer seat 61 with a slight gap in the radial direction when the valve opening height is small. Therefore, the ratio of the increase in the flow passage area to the increase in the piston speed changes between the low speed region and the high speed region, and the ratio of the increase in the damping force to the increase in the piston speed changes between the low speed region and the high speed region.

The first damping force generating mechanism 145A of the second embodiment is configured such that the protruding plate portion 171 and the first gradually decreasing width portion 65 of the first outer holder 61 are opposed to each other in the radial direction in a state where the contact pad 115A is in contact with the first outer holder 61. In this way, the flow passage area between the contact disc 115A and the first gradually decreasing width portion 65, which is not the case where the protruding plate portion 171 and the first gradually decreasing width portion 65 are opposed in the radial direction, is increased as compared to the flow passage area between the contact disc 115A and the first gradually decreasing width portion 65, which is the case where the protruding plate portion 171 and the first gradually decreasing width portion 65 are opposed in the radial direction, and the ratio of the increase in the damping force to the increase in the piston speed is made lower in the high speed region than in the medium speed region of the piston speed.

In this case, the projection plate portion 171 may be provided so as to radially face the first gradually decreasing width portion 65 in a state where the contact pad 115A is placed in contact with the first outer holder 61, and so as not to radially face the first gradually decreasing width portion when the contact pad is separated from the first outer holder 61 by more than a predetermined amount. Further, since the protruding plate portion 171 is formed at the time of press forming on the abutment disk 115A formed by press forming, an increase in the number of components can be suppressed, and an increase in cost can be suppressed.

According to the first aspect of the above-described embodiments, the buffer includes: a cylinder in which a working fluid is sealed; a piston slidably inserted into the cylinder and dividing the interior of the cylinder into two chambers; a piston rod coupled to the piston and extending to the outside of the cylinder; a passage through which a working fluid flows by sliding of the piston; a damping force generating mechanism provided in the passage and configured to control a flow of the working fluid to generate a damping force; the damping force generation mechanism includes: a valve body, the passage penetrating the interior of the valve body; a substantially circular outer seat formed in the valve main body so as to protrude so as to surround an opening of the passage; an inner seat formed on the valve main body to protrude inward of the outer seat; a disk-shaped disk valve that is seated on the outer seat and the inner seat, and that separates from and seats against at least the outer seat by flexing of the outer periphery side; the outer seat has at least one of an inner circumferential side tapered portion whose inner circumferential side expands or an outer circumferential side tapered portion whose outer circumferential side contracts as it moves toward a seat surface on which the disc valve is seated, the disc valve has at least one of an inner protrusion portion radially opposed to the inner tapered portion or an outer protrusion portion radially opposed to the outer tapered portion in a closed valve state seated on the outer seat, after the disc valve starts to open from the closed state, as the disc valve opens, a flow passage area formed between the radially opposed portions of the inner protruding portion and the inner circumferential tapered portion or between the radially opposed portions of the outer protruding portion and the outer circumferential tapered portion is smaller than a flow passage area formed by a gap between the disc valve and a distal end of the outer seat, and the flow passage area is larger than a flow passage area formed by a gap between the disc valve and a distal end of the outer seat.

A second aspect is the disk valve of the first aspect, wherein immediately after the disk valve is opened from the closed state, a flow passage area formed between a portion where the inner protruding portion and the inner circumferential side tapered portion are opposed in the radial direction or a flow passage area formed between a portion where the outer protruding portion and the outer circumferential side tapered portion are opposed in the radial direction is larger than a flow passage area formed in a gap between the disk valve and a tip end of the outer seat.

A third aspect is the disc valve of the first aspect, wherein the disc valve is bent toward the valve main body to form the inner protrusion or the outer protrusion.

A fourth aspect is the disk valve of the first aspect, wherein the inner protrusion or the outer protrusion is formed by a thick portion protruding toward the valve main body side surface.

A fifth aspect is the fourth aspect, wherein the thick portion is formed by attaching another member to a disk closest to the main body.

A sixth aspect is the disc valve according to the first aspect, wherein the disc valve is formed of a plurality of discs, the disc closest to the main body side is a valve having a smaller diameter than the inner tapered portion, and an outer peripheral portion of the valve having the smaller diameter is the inner protruding portion.

Industrial applicability of the invention

Description of the reference numerals

10 buffer

11 cylinder body

12 piston

13 piston rod

19 first chamber

20 second chamber

31 piston body (valve body)

61 first outer seat (outer seat)

65 first width gradually decreasing part (width gradually decreasing part)

71 first inner base (inner base)

76 first pass (pass)

77 first opening part (opening part)

115. 115A butting disk (dish)

136 convex part

145. 145A first damping force generating mechanism (damping force generating mechanism)

171 projecting plate part (convex part)

Claims

1. A shock absorber is characterized by comprising:

a cylinder in which a working fluid is sealed;

a piston slidably inserted into the cylinder and dividing the interior of the cylinder into two chambers;

a piston rod coupled to the piston and extending to the outside of the cylinder;

a passage through which a working fluid flows by sliding of the piston;

a damping force generating mechanism provided in the passage and configured to control a flow of the working fluid to generate a damping force;

the damping force generation mechanism includes:

a valve body, the passage penetrating the interior of the valve body;

a substantially circular outer seat formed in the valve main body so as to protrude so as to surround an opening of the passage;

an inner seat formed on the valve main body to protrude inward of the outer seat;

a disk-shaped disk valve that is seated on the outer seat and the inner seat, and that separates from and seats against at least the outer seat by flexing of an outer peripheral side;

the outer seat has at least one of an inner circumferential side tapered portion whose inner circumferential side expands or an outer circumferential side tapered portion whose outer circumferential side contracts as it moves toward a seat surface on which the disc valve is seated,

the disc valve has a protruding portion that is disposed on a side closer to the valve main body than an opposing surface of the outer seat in a valve-closed state seated on the outer seat and that protrudes so as to approach or abut at least one of the inner peripheral side tapered portion and the outer peripheral side tapered portion,

the increase rate of the flow path area with respect to the increase in the valve opening height is larger in a section from the first valve opening height to a second valve opening height that is further opened than the first valve opening height than in a section in which the valve opening height of the disk valve is increased from the valve closed state to the first valve opening height after the valve opening is started.

2. The buffer of claim 1,

the disc valve forms an inner protrusion or an outer protrusion by being bent toward one side of the valve body.

3. The buffer of claim 1,

the disk valve has an inner protrusion or an outer protrusion formed by a wall thickness portion protruding toward one surface of the valve body.

4. The buffer of claim 3,

the thickness portion is constituted by mounting another member on the disk on the side closest to the valve main body.

5. The buffer of claim 1,

the disc valve is formed of a plurality of discs, and the disc closest to the valve body is a valve having a smaller diameter than the inner circumferential tapered portion, and the outer circumferential portion of the valve having the smaller diameter is an inner protruding portion.