JP6921201B2 - Buffer - Google Patents

Description

The present invention relates to a shock absorber.
The present application claims priority based on Japanese Patent Application No. 2017-154817 filed in Japan on August 9, 2017, the contents of which are incorporated herein by reference.

In the shock absorber, the disc is detached from the outer seat when the piston speed is in the medium speed range, and the disc is detached from the intermediate seat when the piston speed is in the high speed range, so that the damping force increases with respect to the increase in the piston speed. In some cases, the ratio of is lower in the high speed range than in the medium speed range (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2014-70658

There is a desire to reduce the ratio of the increase in damping force to the increase in piston speed.

The present invention provides a shock absorber capable of reducing the ratio of an increase in damping force to an increase in piston speed with a simple structure.

According to one aspect of the present invention, the shock absorber is connected to a cylinder in which a working fluid is sealed, a piston that is slidably inserted into the cylinder and defines the inside of the cylinder into two chambers, and the piston. A piston rod that extends to the outside of the cylinder, a passage through which the working fluid flows due to the sliding of the piston, and a damping force generating mechanism provided in the passage that controls the flow of the working fluid to generate a damping force. And. The damping force generating mechanism includes a valve body through which the passage penetrates, a substantially circular outer seat formed in the valve body so as to surround the opening of the passage, and the outer seat in the valve body. It is provided with an inner seat that is formed so as to project inward, and a disk-shaped disc valve that is seated on the outer seat and the inner seat and is seated on the outer peripheral seat at least by bending the outer peripheral side. The outer seat has at least one of an inner peripheral side taper portion in which the inner peripheral side expands toward the seat surface on which the disc valve is seated and an outer peripheral side tapered portion in which the outer peripheral side contracts. The disc valve has at least one of an inner protruding portion that is radially opposed to the inner tapered portion or an outer protruding portion that is radially opposed to the outer tapered portion in a closed state seated on the outer seat. After the disc valve is opened from the closed state, as the valve is opened, the inner protruding portion is between the portions facing the inner peripheral side tapered portion in the radial direction, or the outer protruding portion is the outer periphery. A state in which the flow path area formed between the side tapered portion and the portion facing in the radial direction is smaller than the flow path area formed in the gap between the disc valve and the top of the outer seat. become.

According to the above-mentioned shock absorber, the ratio of the increase in the damping force to the increase in the piston speed can be reduced by a simple configuration.

It is a front view which made a part of the shock absorber of the 1st Embodiment which concerns on this invention as a cross section. It is sectional drawing which shows the main part of the shock absorber of 1st Embodiment which concerns on this invention. It is an enlarged cross-sectional view which shows the main part of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is a top view which shows the contact disk of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is a figure explaining the state of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is a figure explaining the state of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is a figure explaining the state of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is a characteristic diagram which shows the relationship of the flow path area with respect to the valve opening height of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is an enlarged cross-sectional view which shows the main part of the modification 1 of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is an enlarged cross-sectional view which shows the main part of the modification 2 of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is an enlarged cross-sectional view which shows the main part of the modification 3 of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is an enlarged cross-sectional view which shows the main part of the modification 4 of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is an enlarged cross-sectional view which shows the main part of the modification 5 of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is an enlarged cross-sectional view which shows the main part of the modification 6 of the 1st damping force generation mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is an enlarged cross-sectional view which shows the main part of the 1st damping force generation mechanism of the shock absorber of the 2nd Embodiment which concerns on this invention.

[First Embodiment]
The first embodiment according to the present invention will be described below with reference to FIGS. 1 to 12.

The shock absorber 10 of the first embodiment is a fluid pressure shock absorber using a liquid or a gas as a working fluid. Specifically, the shock absorber 10 is a hydraulic shock absorber that uses an oil liquid as a working fluid. As shown in FIG. 1, the shock absorber 10 has a cylinder 11 in which a working fluid is 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.

A piston rod 13 is inserted into the cylinder 11. The piston 12 is connected 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 extends to the outside of the cylinder 11. The piston rod 13 having one end connected to the piston 12 has the other end side inserted into the rod guide 15 and the oil seal 16 mounted on the opening of the cylinder 11 and extend to the outside of the cylinder 11. The piston 12 has a first chamber 19 between the inside of the cylinder 11 and the free piston 18 on the bottom 17 side (lower side in FIG. 1) of the cylinder 11 and an opening side (in FIG. 1) on which the piston rod 13 extends. It is defined in two rooms, the second room 20 (upper side).

As shown in FIG. 2, the piston rod 13 has a spindle portion 25 and a mounting shaft portion 26 at the end of the piston rod 13 in the cylinder 11 and having a diameter smaller than that of the spindle portion 25.
As a result, the spindle portion 25 is formed with an end face 27 extending in the direction orthogonal to the axis at the end portion on the mounting shaft portion 26 side. The mounting shaft portion 26 is formed with a male screw 28 for screwing the female screw 30 of the nut 14 in a predetermined range on the opposite side of the main shaft portion 25.

The piston 12 has an annular piston body 31 (valve body) and an annular band-shaped sliding contact member 33 that is mounted on the outer peripheral surface of the piston body 31 and is in sliding contact with the inner peripheral surface of the cylinder 11. Therefore, the piston 12 including the piston body 31 and the sliding contact member 33 has an annular shape. The piston body 31 is made of metal. The piston body 31 is integrally molded by sintering. The sliding contact member 33 is made of synthetic resin. The central axis of the piston body 31 and the piston 12 to which the sliding contact member 33 is integrally mounted are aligned with each other. As a result, the piston body 31 and the piston 12 have the same axial direction along the central axis, the radial direction orthogonal to the central axis, and the circumferential direction around the central axis. do.

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 is formed with a first passage hole 41 and a second passage hole 42 extending in the axial direction of the piston body 31 at positions outside the insertion hole 35 in the radial direction.

The first passage hole 41 is arranged so that the first chamber 19 side is closer to the inner peripheral side of the piston body 31 in the radial direction than the second chamber 20 side. The second passage hole 42 is arranged so that the second chamber 20 side is closer to the inner peripheral side of the piston body 31 in the radial direction than the first chamber 19 side.

The piston body 31 is provided with a plurality of first passage holes 41 (only one is shown in FIG. 2 due to the cross section). The second passage holes 42 are also provided in the same number as the first passage holes 41 (only one place is shown in FIG. 2 due to the cross section). The first passage hole 41 and the second passage hole 42 are alternately arranged in the circumferential direction of the piston main body 31.

The piston body 31 is formed with an opening surface 52 on the first chamber 19 side through which the openings 51 on the first chamber 19 side of all the first passage holes 41 are opened. An opening surface 54 is formed outside the opening surface 52 in the radial direction of the piston body 31 so that the openings 53 on the first chamber 19 side of all the second passage holes 42 open.

The piston main body 31 is formed on the first chamber 19 side so as to project from the opening surfaces 52 and 54 in the axial direction of the piston main body 31 so as to surround all the openings 51 on the radial outside of the piston main body 31. It has a circular first outer sheet 61 (outer sheet). The first outer sheet 61 has an inner tapered surface 62, an outer tapered surface 63, and a tip surface 64. The inner tapered surface 62 has a larger diameter (the inner diameter increases) toward the protruding tip side (toward the seat surface) in the radial direction. The outer tapered surface 63 has a smaller diameter (the outer diameter is reduced) toward the protruding tip side (toward the seat surface) outward in the radial direction. The tip surface 64 is a flat surface extending in the direction orthogonal to the axis toward the protruding tip side. The protruding tip side of the first outer sheet 61 has these tapered surfaces 62 and 63 and the tip surface (seat surface) 64, and the first width gradually decreasing portion 65 (width) whose radial width gradually decreases toward the protruding tip side. It is a gradual decrease part). The opening surface 52 is arranged inside the tapered surface 62 in the radial direction. The opening surface 54 is arranged on the radial outer side of the tapered surface 63.

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

An annular first annular passage 75 that communicates all the first passage holes 41 between the first outer sheet 61 and the first inner sheet 71, that is, between the opening surface 52, the tapered surface 62, and the tapered surface 72. It has become. All the first passage holes 41 and the first annular passage 75 form a first passage 76 (passage) that penetrates the piston 12 in the axial direction. The working fluid flows through the first passage 76 due to the sliding of the piston 12 with respect to the cylinder 11.

Between the tip surface 64 of the first outer sheet 61 and the tip surface 73 of the first inner sheet 71 is a first opening 77 (opening) on the first chamber 19 side of the first passage 76. Therefore, the substantially circular first outer sheet 61 is formed on the piston main body 31 so as to surround the first opening 77 of the first passage 76 so as to project from the opening surface 52. Further, the first opening 77 of the first passage 76 is arranged between the first outer sheet 61 and the first inner sheet 71.

The piston body 31 is formed with an opening surface 82 on the second chamber 20 side through 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 outer side of the opening surface 82 in the radial direction of the piston body 31 so that the openings 83 on the second chamber 20 side of all the first passage holes 41 open.

The piston body 31 has a substantially circular second outer seat 91 on the second chamber 20 side. The second outer sheet 91 is formed so as to surround all the openings 81 with the radial outer side of the piston body 31. The second outer sheet 91 is formed so as to project in the axial direction of the piston body 31 from the opening surfaces 82 and 84. The second outer sheet 91 has a tapered surface 92, a tapered surface 93, and a tip surface 94. The tapered surface 92 has a larger diameter toward the tip side protruding inward in the radial direction. The tapered surface 93 has a smaller diameter toward the tip side protruding outward in the radial direction. The tip surface 94 is a flat surface extending in the direction orthogonal to the axis toward the protruding tip side. The protruding tip side of the second outer sheet 91 is a second width gradually reducing portion 95 having these tapered surfaces 92 and 93 and a tip surface 94, and the radial width gradually decreases toward the protruding tip side. The opening surface 82 is arranged inside the tapered surface 92 in the radial direction. The opening surface 84 is arranged on the radial outer side of the tapered surface 93.

The piston body 31 is provided with a substantially circular second inner sheet 101 on the second chamber 20 side. The 2 inner sheet 101 is arranged inside the piston body 31 in the radial direction with respect to the second outer sheet 91. 2 The inner sheet 101 is formed so as to project from the opening surface 82 in the axial direction of the piston body 31. The opening surface 82 and all the openings 81 are arranged between the second outer sheet 91 and the second inner sheet 101. The second inner sheet 101 has a tapered surface 102 and a tip surface 103. The tapered surface 102 has a smaller diameter toward the tip side protruding outward in the radial direction. The tip surface 103 is a flat surface extending in the direction orthogonal to the axis toward the protruding tip side. The inner peripheral side of the second inner sheet 101 has an insertion hole 35. The outer diameter of the tip surface 103 is substantially the same as the outer diameter of the end surface 27 of the piston rod 13.

An annular second annular passage 105 that communicates all the second passage holes 42 between the second outer sheet 91 and the second inner sheet 101, that is, between the opening surface 82, the tapered surface 92, and the tapered surface 102. It has become. All the second passage holes 42 and the second annular passage 105 form a second passage 106 that penetrates the piston 12 in the axial direction. The working fluid flows through the second passage 106 by sliding the piston 12 with respect to the cylinder 11.

The space between the tip surface 94 of the second outer sheet 91 and the tip surface 103 of the second inner sheet 101 is the second opening 107 on the second chamber 20 side of the second passage 106. Therefore, the substantially circular second outer sheet 91 is formed on the piston main body 31 so as to surround the second opening 107 of the second passage 106 so as to project from the opening surface 82. Further, the second opening 107 of the second passage 106 is arranged between the second outer sheet 91 and the second inner sheet 101.

The piston body 31 has a shape in which the front and back sides are indistinguishable. Therefore, even if the piston body 31 is turned upside down and attached to the piston rod 13, the above configuration is obtained.

On the end surface 27 of the main shaft portion 25 of the piston rod 13, one regulating member 111, two small diameter discs 112, one large diameter disc 113, and one, which are all made of metal and form an annular shape, are formed. Contact disk 114, piston 12, one contact disk 115 (disk), two large diameter disks 116, one intermediate diameter disk 117, one intermediate diameter disk 118, Two small-diameter disks 119 and one regulating member 120 are stacked in this order with the mounting shaft portion 26 fitted inside each of them. In this state, the nut 14 is screwed into the male screw 28 protruding from the regulation member 120 of the mounting shaft portion 26 with the female screw 30.

By fastening the nut 14 to the male screw 28, one regulating member 111, two small diameter discs 112, one large diameter disc 113, one contact disc 114, a piston 12, and one contact disc 115. , Two large-diameter discs 116, one intermediate-diameter disc 117, one intermediate-diameter disc 118, two small-diameter discs 119, and one regulating member 120 are all in the radial direction at the mounting shaft portion 26. The movement is restricted and laminated, and in this laminated state, the piston rod 13 is sandwiched between the end face 27 and the nut 14. Then, at least the inner peripheral side of these is fixed to the piston rod 13 so as not to move in the axial direction. As a result, only the inner peripheral side of the large-diameter disc 113, the abutting disc 114, the abutting disc 115, the two large-diameter discs 116, and the intermediate-diameter discs 117 and 118 cannot move in the axial direction with respect to the piston rod 13. Clamped to.

The outer diameter of the regulating member 111 is larger than the outer diameter of the end surface 27 and the outer diameter of the tip surface 103. The small diameter disc 112 has a flat plate shape, and the outer diameter is the same as the outer diameter of the end face 27. The large-diameter disc 113 has a flat plate shape, and the outer diameter is larger than the outer diameter of the small-diameter disc 112, which is substantially the same as the outer diameter of the tip surface 94 of the second outer sheet 91.

The abutting disc 114 has a flat plate shape, and its outer diameter is the same as that of the large diameter disc 113. The contact disk 114 is seated in contact with the tip surface 94 of the second outer sheet 91 and the tip surface 103 of the second inner sheet 101. The abutting disc 114 and the large diameter disc 113 constitute the disc 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 is deformed so that the portion radially outer of the small diameter disc 112 is separated from the piston body 31, and the second outer seat 91. The seat is separated from the tip surface 94 of the.

As shown in FIG. 3, the contact disk 115 has a substrate portion 131, an inner protruding plate portion 132, a tip plate portion 133, an outer protruding plate portion 134, and an outer end plate portion 135. .. The substrate portion 131 expands in the radial direction. The inner protruding plate portion 132 projects from the outer peripheral edge portion of the substrate portion 131 to one side in the plate thickness direction. The tip plate portion 133 extends radially outward from the end edge portion of the inner protruding plate portion 132 opposite to the substrate portion 131. The outer protruding plate portion 134 projects from the outer peripheral edge portion of the tip plate portion 133 in the same direction as the protruding direction of the inner protruding plate portion 132 with respect to the tip plate portion 133. The outer end plate portion 135 extends radially outward from the end edge portion of the outer protruding plate portion 134 opposite to the tip plate portion 133.

The substrate portion 131 is an annular flat plate extending radially outward from the inner end position of the contact disk 115. The outer end plate portion 135 is an annular flat plate located at the outer end position in the radial direction of the contact disk 115. The substrate portion 131 and the outer end plate portion 135 are arranged on the same plane. The inner protruding plate portion 132 has a tapered tubular shape whose diameter increases as the distance from the substrate portion 131 in the axial direction increases. The outer protruding plate portion 134 has a tapered tubular shape whose diameter becomes smaller as the distance from the outer end plate portion 135 in the axial direction increases. In other words, the inner protruding plate portion 132 projects from the substrate portion 131 and the outer end plate portion 135 while increasing the diameter. The outer protruding plate portion 134 projects from the substrate portion 131 and the outer end plate portion 135 while reducing the diameter. The tip plate portion 133 is an annular flat plate, and is arranged in parallel with the substrate portion 131 and the outer end plate portion 135.

The inner protruding plate portion 132, the tip plate portion 133, and the outer protruding plate portion 134 form a convex portion 136 that protrudes in the axial direction from the substrate portion 131 and the outer end plate portion 135 on both sides in the radial direction. As shown in FIG. 4, the convex portion 136 (inner protruding portion) has an annular shape.

The contact disk 115 is formed with a plurality of notches 138, specifically, two notches, at equal intervals in the circumferential direction. The cutout portion 138 penetrates in the plate thickness direction and exits from the portion on the inner protruding plate portion 132 side of the tip plate portion 133 to the outer side in the radial direction through the outer protruding plate portion 134 and the outer end plate portion 135.

The abutting disk 115 is formed into the above shape by press molding from a flat metal plate having a constant plate thickness. Therefore, as shown in FIG. 3, the inner protruding plate portion 132, the tip plate portion 133, and the outer protruding plate portion 134 forming the convex portion 136 of the contact disk 115 are substantially the same as the substrate portion 131 and the outer end plate portion 135. It is the thickness of.

The outer diameter of the abutting disk 115 excluding the cutout portion 138 of the outer end plate portion 135 is the same as the outer diameter of the tip surface 64 of the first outer sheet 61. Further, in the contact disk 115, the outer diameter of the end portion of the outer peripheral surface 140 of the outer protruding plate portion 134 on the outer end plate portion 135 side is slightly smaller than the inner diameter of the tip surface 64 of the first outer sheet 61. There is. The outer peripheral surface 140 of the outer protruding plate portion 134 has a taper equivalent to the tapered surface 62 of the first width tapering portion 65 of the first outer sheet 61.
It is also possible to make one taper of the outer peripheral surface 140 and the tapered surface 62 larger than the other taper, and conversely, make the other taper larger than the one taper.

The contact disk 115 is in a state in which the convex portions 136 project from the substrate portion 131 and the outer end plate portion 135 on both sides in the radial direction toward the piston 12, and the outer end plate portion 135 is the facing surface 141 on the piston 12 side. The substrate portion 131 faces the tip surface 64 of the first outer sheet 61 and sits in contact with the tip surface 73 of the first inner sheet 71 shown in FIG.

In this state, as shown in FIG. 3, the tip surface 142 of the tip plate portion 133 of the contact disk 115 is located closer to the opening surface 52 than the tip surface 64 of the first outer sheet 61. The notch 138 of the contact disk 115 makes the first passage 76 into the first chamber 19 even when the contact disk 115 is seated on the tip surface 64 of the first outer sheet 61 on the facing surface 141 of the outer end plate portion 135. Form a fixed orifice to communicate. Instead of forming the notch 138 in the contact disk 115, the first outer sheet 61 may be provided with a notch penetrating the notch in the radial direction so as to be recessed from the tip surface 64 to form a fixed orifice. good. That is, the contact disk 115 forms an inner protruding portion by the tip surface 142 as a thick portion protruding on the surface on the piston 12 side as the valve body.

The abutting disk 115 has an annular convex portion 136 seated on the tip surface 64 of the first outer seat 61 of the piston body 31 on the facing surface 141 of the outer end plate portion 135 (valve lift amount = 0). , Enters the radial inside of the annular first width tapering portion 65 of the first outer sheet 61.
At that time, the tapered surface 62 of the first width tapering portion 65 inclined with the same taper and the outer peripheral surface 140 of the outer protruding plate portion 134 overlap each other in the axial direction and face each other with a slight gap in the radial direction. ..

In other words, in the contact disk 115, the annular convex portion 136 is the annular first width tapering portion of the piston body 31 in a state where the contact disk 115 is seated on the tip surface 64 of the first outer sheet 61 at the outer end plate portion 135. The positions of 65 and the axial direction are overlapped and face each other in the radial direction. The width of the first width gradually decreasing portion 65 of the first outer sheet 61 gradually decreases toward the contact disk 115.

As shown in FIG. 3, the large-diameter disc 116 has a flat plate shape, and the outer diameter is the same as the outer diameter of the portion of the outer end plate portion 135 of the contact disc 115 excluding the cutout portion 138. The intermediate diameter disc 117 has a flat plate shape, and the outer diameter is smaller than the outer diameter of the large diameter disc 116. As shown in FIG. 2, the intermediate diameter disc 118 has a flat plate shape, and the outer diameter is smaller than the outer diameter of the intermediate diameter disc 117. The small diameter disc 119 has a flat plate shape, and the outer diameter is smaller than the outer diameter of the intermediate diameter disc 118, and is substantially the same as the outer diameter of the tip surface 73 of the first inner sheet 71. The small-diameter disk 119 is a common component with the small-diameter disk 112. The outer diameter of the regulating member 120 is larger than the outer diameter of the small diameter disk 119. The regulating member 120 is a common component with the regulating member 111.

The abutting disc 115, the large diameter disc 116, the intermediate diameter disc 117 and the intermediate diameter disc 118 constitute the 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 is deformed so that the portion outside the small diameter disc 119 is separated from the piston body 31 and the tip of the first outer seat 61. Leave the surface 64.

A first damping force generating mechanism in which a disc valve 144 and a first outer seat 61 and a first inner seat 71 on which the disc valve 144 is seated are provided in the first passage 76 to control the flow of working fluid and generate a damping force. It constitutes 145 (damping force generation mechanism). The first damping force generation mechanism 145 controls the damping force by controlling the minimum flow path area (hereinafter, simply referred to as the flow path area) in the first passage 76. This flow path area is the area of the gap between the first outer seat 61 and the disc valve 144. The opening 53 of the second passage 106 is arranged radially outside the disc valve 144, and the second passage 106 is not blocked by the disc valve 144.

A second damping force generating mechanism in which the disc valve 127 and the second outer seat 91 and the second inner seat 101 on which the disc valve 127 is seated are provided in the second passage 106 to control the flow of the working fluid and generate a damping force. It constitutes 148. The second damping force generation mechanism 148 controls the flow path area of the second passage 106 to control the damping force. This flow path area is the area of the gap between the second outer seat 91 and the disc valve 127. The opening 83 of the first passage 76 is arranged radially outside the disc valve 127, and the first passage 76 is not blocked by the disc valve 127.

The piston body 31, the regulating member 111, and the regulating member 120 have higher rigidity than 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, respectively. ing. The regulating member 111 suppresses further deformation of the disc valve 127 when the deformed disc valve 127 is in contact with the regulating member 111. The regulating member 120 suppresses further deformation of the disc valve 144 when the deformed disc valve 144 is in contact with the regulating member 120.

In the extension stroke in which the piston rod 13 moves to the extension side with respect to the cylinder 11 in the shock absorber 10, the pressure in the second chamber 20 is higher than the pressure in the first chamber 19 due to the piston 12 moving integrally with the piston rod 13. Cylinder. As a result, the working fluid of the second chamber 20 is introduced into the plurality of first passage holes 41 of the first passage 76 from the openings 83 of the respective constant openings. The working fluid introduced from the opening 83 exits from the opening 51 into the first annular passage 75 and joins to act on the disc valve 144 closing the first opening 77.

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 does not separate the disc valve 144 of the first damping force generating mechanism 145 from the first outer seat 61. 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 disk 115 and the tip surface 64 of the first outer sheet 61 is maintained. Then, the working fluid of the second chamber 20 flows from the first passage 76 to the first chamber 19 through the notch 138 as a fixed orifice of the contact disk 115 of the disc valve 144. As a result, the flow path area of the first passage 76 becomes constant, so that a damping force having an orifice characteristic (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 disengages the disc valve 144 including the contact disk 115 of the first damping force generating mechanism 145 from the first outer seat 61.
At this time, a damping force having valve characteristics (damping force is substantially proportional to the piston speed) is generated according to the flow path area between the disc valve 144 and the first outer seat 61, which is the flow path area of the first passage 76. do.

The disc valve 144 is separated from the first outer seat 61 by the 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 abutting disk 115 and the tip surface 64 of the first outer sheet 61, is proportional to this differential pressure.

In the first embodiment, the contact disk 115 faces the first width tapering portion 65 of the first outer sheet 61 with a slight gap in the radial direction in a small state including a valve closed state where the valve opening height is 0. A convex portion 136 including an outer protruding plate portion 134 is provided. As a result, the ratio of the increase in the flow path area to the increase in the piston speed changes in 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 in the low speed region and the high speed region.

The ratio of the increase in the flow path area to the increase in the piston speed and the ratio of the increase in the damping force in the first embodiment will be described in more detail with reference to FIGS. 5A to 6. 5A to 5C are diagrams for explaining the state of the first damping force generating mechanism of the shock absorber of the first embodiment. FIG. 5A shows a valve closed state in which the first width tapering portion 65 is in contact with the contact disk 115 and the valve opening height is 0. FIG. 5B is a diagram showing a state in which the first width tapering portion 65 is separated from the contact disk 115 by a predetermined distance h _b. Figure 5C with respect to the contact disk 115 is a diagram illustrating a state in which the first width gradually decreasing portion 65 is spaced by a predetermined distance h _c. As described above, the distance between the contact disk 115 and the first width tapering portion 65 represents the valve opening height.
FIG. 6 is a characteristic diagram showing the relationship of the flow path area with respect to 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. Point a shown in FIG. 6 corresponds to the state of FIG. 5A. Point b shown in FIG. 6 corresponds to the state of FIG. 5B. Point c shown in FIG. 6 corresponds to the state of FIG. 5C.
That is, FIG. 5A shows a valve closed state in which the valve opening height is 0. In the section a~b up to a predetermined height as shown in FIG. 5B, starting from the closed state, as shown in FIG. 6, the flow passage area S _ab increases proportionately with an increase in the valve opening height h. The sections a to b include a range in which the contact disk 115 and the first width tapering portion 65 having the inner tapered surface 62 (in which the inner diameter is expanded) overlap the positions in the valve opening height direction and face each other in the radial direction. Includes. Then, in the sections b to c from the predetermined height shown in FIG. 5B to the further increase in the valve opening height h as shown in FIG. 5C, as shown in FIG. 6, the valve opening height h increases. On the other hand, the flow path area S _bc increases proportionally at a higher rate than the sections a to b. Passage area formed in the gap formed by the abutment disc 115 as a first outer sheet 61 and the disc valve is a top of the outer sheet is less than S _ab, then section a~b also the condition Continues. After that, the flow path area S _bc between the sections b to c is larger than the gap formed by the first outer seat 61 which is the top of the outer seat and the abutting disc 115 as a disc valve. That is, the area changes from smaller to larger than the flow path area formed in the gap between the contact disk 115 and the top of the first outer sheet 61.

As shown in FIG. 5A, the radius of the inner peripheral edge of the tip surface 64 of the first outer sheet 61 is r ₁ , the radius of the outer peripheral edge of the tip surface 142 of the contact disk 115 is r ₂ , and the contact disk 115. Let H be the height from the facing surface 141 to the tip surface 142. Further, as shown in FIG. 5B, the inclination angle of the tapered surface 62 of the first outer sheet 61 with respect to the central axis is set to θ _1, and the inclination angle of the outer peripheral surface 140 of the contact disk 115 with respect to the central axis is set to θ _{2. Let h b be} the height from the facing surface 141 of the contact disk 115 to the tip surface 64 of the first outer sheet 61. Further, as shown in FIG. 5C, the height from the facing surface 141 of the contact disk 115 to the tip surface 64 of the first outer sheet 61 in the sections _b to c is defined as h c.

Then, the flow path area Sab in the sections a to _b can be obtained by the following equation (1).
S _ab ≈ 2πr ₁ h _b cos θ ₂ ... (1)
Here, 0 <h _b <H + h _b cos ² θ ₂ .

Further, the flow path area S _bc in the sections b to c can be obtained by the following equation (2).
S _bc ≈ 2πr ₁ square {(r ₁ − r ₂ ) ² + (h _{c −} h _b ) ² } ··· (2)
here, When h _b = H + h _b cos ² θ ₂ , _Sub = S _bc .

By the above, the valve opening height _is greater than S ab _{= S bc} become open height _{h b,} the rate of increase in flow area for the valve opening height, the _S ab _{= S bc} from the closed state It is larger than the rate of increase in the section up to the valve opening height h _b. Therefore, the valve opening height _exceeds the valve opening height _{h b} of the S ab _{= S bc,} compared to sections from the closed state to the _S ab _{= S bc} become open height _{h b,} the 1. The ratio of the increase in the damping force to the increase in the piston speed of the damping force generation mechanism 145 can be suppressed. _{As described above, in the sections a to b} from the valve closed state to the valve opening height h _{b where S ab} = S _bc , the contact disk 115 and the first width tapering portion 65 are positioned in the valve opening height direction. Are overlapped and include a range facing each other in the radial direction.

As a result, the ratio of the increase in the damping force to the increase in the piston speed is lower in the speed range in which the piston speed in the sections b to c is faster than in the speed range in which the piston speed in the sections a to b is slow.

The flow path area S _bc is the flow path area between the contact disk 115 and the first width gradual reduction portion 65 when it does not face the first width gradual reduction portion 65 in the radial direction, and the diameter of the first width gradual reduction portion 65. It is larger than the _{flow path area Sab,} which is the flow path area between the contact disk 115 and the first width tapering portion 65 when facing each other in the direction. In other words, the first width is compared with the flow path area of the first passage 76 determined by the distance relationship between the contact disk 115 and the first width gradually decreasing portion 65 when facing the first width gradually decreasing portion 65 in the radial direction. The flow path area of the first passage 76, which is determined by the distance relationship between the contact disk 115 and the first width tapering portion 65 when the tapering portion 65 does not face in the radial direction, is larger. In other words, when the piston speed enters the high speed range from the low speed range and the valve opening height of the contact disk 115 exceeds a predetermined value, the ratio of the increase in the flow path area to the increase in the valve opening height becomes higher than before. Also increases, and the rate of increase in damping force with respect to the increase in piston speed is suppressed to a lower rate than before.

In the contraction stroke in which the piston rod 13 shown in FIG. 2 moves to the contraction side with respect to the cylinder 11, the pressure in the first chamber 19 is higher than the pressure in the second chamber 20 by the piston 12 that moves integrally with the piston rod 13. As a result, the working fluid of the first chamber 19 is introduced into the plurality of second passage holes 42 of the second passage 106 from the openings 53 of the respective constant openings. The working fluid introduced from the opening 53 exits from the opening 81 into the second annular passage 105 and joins, and acts on the disc valve 127 of the second damping force generating mechanism 148 that closes the second opening 107.

Then, the working fluid of the second passage 106 separates the disc valve 127 from the second outer seat 91 to open the valve. As a result, the working fluid flows from the first chamber 19 to the second chamber 20 through the second passage 106 in a flow path area corresponding to the valve opening amount between the disc valve 127 and the second outer seat 91. Therefore, the damping force of the valve characteristic is generated.

In Patent Document 1 described above, the disc is detached from the outer seat when the piston speed is in the medium speed range, and the disc is detached from the intermediate seat when the piston speed is in the high speed range. A shock absorber that reduces the rate of increase in damping force in the high speed range rather than in the medium speed range is described. In the high speed range of piston speed, this shock absorber allows the working fluid to flow from between the intermediate sheet and the disk, which have a smaller diameter than the outer sheet, so that the flow path area cannot be sufficiently widened and damping with increasing piston speed. It may not be possible to reduce the rate of force increase sufficiently.

On the other hand, in the first damping force generating mechanism 145 of the shock absorber 10 of the first embodiment, the first width of the first outer sheet 61 is in a state where the contact disk 115 is in contact with the first outer sheet 61. It faces the tapering portion 65 in the radial direction at the convex portion 136. As a result, the first width gradual reduction portion 65 is radially opposed to the flow path area between the contact disk 115 and the first width gradual reduction portion 65 when facing the first width gradual reduction portion 65 in the radial direction. By increasing the flow path area between the contact disk 115 and the first width gradual reduction portion 65 when not facing each other, the ratio of the increase in damping force to the increase in piston speed can be increased from the medium speed range of piston speed. Also lower in the high speed range. Therefore, as in the medium speed range of the piston speed, the working fluid flows from between the first outer sheet 61 and the contact disk 115 even in the high speed range of the piston speed, so that the flow path area can be sufficiently widened and the piston speed can be increased. The ratio of the increase in damping force to the increase in is sufficiently small.

Further, the increase in the flow path area at the initial stage of valve opening of the first damping force generating mechanism 145 can be moderated, the sudden pressure change can be suppressed, and the generation of sound caused by the sudden pressure change can be suppressed.

Further, when the contact disk 115 is in contact with the first outer sheet 61 and faces the first width tapering portion 65 in the radial direction and is separated from the first outer sheet 61 by more than a predetermined amount, the first width tapering portion is formed. Since the convex portion 136 may be provided so as not to face the 65 in the radial direction, the ratio of the increase in the damping force to the increase in the piston speed is made lower in the high speed range than in the medium speed range of the piston speed with a simple structure. be able to.

Further, a convex portion 136 is formed on the contact disk 115 formed by press molding during press molding. Therefore, an increase in the number of parts can be suppressed, and an increase in cost can be suppressed.

In the above, the convex portion 136 is formed on the abutting disk 115, but as in the modified example 1 shown in FIG. 7, the abutting disk 115 is a main body disk 151 made of a flat plate and a radially opposed disk made of a flat plate. It may be configured with 152. The main body disk 151 has an facing surface 141 seated on the tip surface 64 of the first outer seat 61. The radial facing disk 152 is arranged inside the first outer sheet 61 in the radial direction in a state where the main body disk 151 is seated on the tip surface 64 of the first outer sheet 61 on the facing surface 141, and the first width gradually decreasing portion 65. It has an outer peripheral surface 140 and a tip surface 142 facing each other in the radial direction by superimposing positions in the axial direction.

Further, as described above, the convex portion 136 of the contact disk 115 is formed by the inner protruding plate portion 132, the tip plate portion 133, and the outer protruding plate portion 134 having the same thickness as the substrate portion 131 and the outer end plate portion 135. Instead, as shown in the second modification shown in FIG. 8, the contact disk 115 is made of, for example, a synthetic resin, so that the thickness between the substrate portion 131 and the outer end plate portion 135 is thicker than these. A thick thick portion 155 may be formed, and the thick portion 155 may form a convex portion 136 protruding from the substrate portion 131 and the outer end plate portion 135. In this case, the substrate portion 131, the outer end plate portion 135, and the convex portion 136 can be formed by integrally molding the resin.

Further, as in the modified example 3 shown in FIG. 9, the contact disk 115 is composed of a disk body 161 made of a metal flat plate and a separate member 162 made of synthetic resin provided on the outer peripheral side of the disk body 161. Is also good. The separate member 162 includes a main portion 163 in which a convex portion 136 having an outer peripheral surface 140 and a tip surface 142 and a facing surface 141 are formed and are in close contact with the disc main body 161 and a covering portion 164 in close contact with the outer peripheral surface of the disc main body 161. The disc body 161 has a mounting portion 165 that is in close contact with the main portion 163 on the opposite side. The covering portion 164 connects the outer peripheral edge portion of the main portion 163 and the outer peripheral edge portion of the mounting portion 165. In this case, it is possible to manufacture the disc body 161 by installing the disc body 161 in a mold in which a cavity having the shape of the separate member 162 is formed, pouring a synthetic resin material into the cavity, and forming the separate member 162 on the outer peripheral portion of the disc body 161. Become.

Further, as in the modified example 4 shown in FIG. 10, the contact disk 115 is formed of a flat plate and the disk body 168 forming the facing surface 141 has a convex portion 136 as a separate member having an outer peripheral surface 140 and a tip surface 142. May be glued. In this case, the disk body 168 can be made of metal and the convex portion 136 can be made of synthetic resin. Also in this case, it is possible to manufacture the disk body 168 by installing the disk body 168 in the mold in which the cavity having the shape of the convex portion 136 is formed and pouring the synthetic resin material into the cavity to form the convex portion 136 in the disk body 168.

Further, in the above, the outer peripheral surface 140 of the convex portion 136 of the contact disk 115 is made to have a taper equivalent to the tapered surface 62 of the first outer sheet 61, and these are opposed to each other with a slight gap in the radial direction. As in the modified example 5 shown in 11, the taper of the tapered surface 62 of the first outer sheet 61 is made larger than the taper of the outer peripheral surface 140 of the convex portion 136, and the tapered surface 62 is on the tip surface 142 side of the outer peripheral surface 140. It may be brought into contact with the end portion of the. On the contrary, as in the modified example 6 shown in FIG. 12, the taper of the tapered surface 62 of the first outer sheet 61 is made smaller than the taper of the outer peripheral surface 140 of the convex portion 136, and the tip of the tapered surface 62 is formed. The end portion on the surface 64 side may be brought into contact with the outer peripheral surface 140.

Although not shown, in the modified examples 1 to 6, the contact disk 115 is provided with a notch 138, or the first outer sheet 61 is provided with a notch recessed from the tip surface 64 and penetrating in the radial direction. Consists of a fixed orifice.

[Second Embodiment]
Next, the second embodiment will be described mainly based on FIG. 13, focusing on the differences from the first embodiment. The parts common to the first embodiment are represented by the same title and the same reference numerals.

As shown in FIG. 13, in the second embodiment, the contact disk 115A is partially different from the contact disk 115 of the first embodiment. The contact disk 115A has a substrate portion 131A and a protruding plate portion 171 (convex portion, outward protruding portion). The substrate portion 131A extends radially outward from the radial inner end position of the contact disk 115A. The protruding plate portion 171 projects from the outer peripheral edge portion of the substrate portion 131A to one side in the plate thickness direction. The projecting plate portion 171 is located at the outer end position in the radial direction of the contact disk 115A. That is, the protruding plate portion 171 forms an outer protruding portion by being curved toward the valve body side. The protruding plate portion may be formed inside the first outer sheet 61 to form the inner protruding portion.

The substrate portion 131A is a disk-shaped flat plate. The protruding plate portion 171 has a tapered tubular shape whose diameter increases as the distance from the substrate portion 131A in the axial direction increases. In other words, the protruding plate portion 171 protrudes from the substrate portion 131A while expanding its diameter. The contact disk 115A is formed with a notch portion 138A that penetrates in the plate thickness direction and exits from the projecting plate portion 171 side of the substrate portion 131A through the protruding plate portion 171 to the outside in the radial direction. The abutting disk 115A is formed into the above shape by press molding from a flat metal plate having a constant plate thickness. Therefore, the substrate portion 131A and the protruding plate portion 171 of the contact disk 115A have the same thickness.

In the contact disk 115A, the outer diameter of the substrate portion 131A is substantially the same as the outer diameter of the tip surface 64 of the first outer sheet 61. The inner peripheral surface 172 of the protruding plate portion 171 has a taper equivalent to that of the tapered surface 63 on the radial outer side of the first width tapering portion 65 of the first outer sheet 61. The contact disk 115A is in a state in which the protruding plate portion 171 projects toward the piston 12 from the substrate portion 131A on the inner side in the radial direction thereof, and the substrate portion 131A is a facing surface 141A on the piston 12 side of the first outer sheet 61. It is seated on the tip surface 64 and the tip surface 73 (see FIG. 2) of the first inner sheet 71.

In this state, the tip of the protruding plate portion 171 of the contact disk 115A is located closer to the opening surface 52 than the tip surface 64 of the first outer sheet 61. The notch 138A of the abutting disk 115A constitutes a fixed orifice that allows the first passage 76 to communicate with the first chamber 19 even when the abutting disk 115A is seated on the tip surface 64 of the first outer sheet 61. The first outer sheet 61 may be provided with a notch that is recessed from the tip surface 64 and penetrates in the radial direction to form a fixed orifice.

In the abutting disk 115A, the annular protruding plate portion 171 is seated on the tip surface 64 of the first outer sheet 61 of the piston body 31 in the substrate portion 131A, and the annular protruding plate portion 171 is the first annular portion of the first outer sheet 61. The width tapering portion 65 is inserted inside in the radial direction. At that time, the tapered surface 63 of the first width tapering portion 65 inclined with the same taper and the inner peripheral surface 172 of the protruding plate portion 171 overlap the axial positions and face each other with a slight gap in the radial direction. ..

In other words, in the contact disk 115A, the annular protruding plate portion 171 is seated on the tip surface 64 of the first outer sheet 61 in the substrate portion 131A, and the annular protruding plate portion 171 is the annular first width tapering portion 65 of the piston body 31. And the axial position are overlapped and face each other in the radial direction. In the protruding plate portion 171, the protrusion is compared with the flow path area of the first passage 76 determined by the distance relationship between the contact disk 115A and the first width gradually decreasing portion 65 when facing the first width gradually decreasing portion 65 in the radial direction. The flow path area of the first passage 76 determined by the distance relationship between the contact disk 115A and the first width gradual reduction portion 65 when the plate portion 171 does not face the first width gradual reduction portion 65 in the radial direction is larger.

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 the 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 144A is seated constitute a first damping force generating mechanism 145A (damping force generating mechanism).

In the extension stroke, the working fluid of 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 does not separate the disc valve 144A of the first damping force generating mechanism 145A from the first outer seat 61. It flows into the first chamber 19 through the notch 138A as the fixed orifice of the abutting disk 115A, and the damping force of the orifice characteristic is generated.

Further, in a speed range in which the piston speed is higher than this, the working fluid in the first passage 76 separates the disc valve 144A of the first damping force generating mechanism 145A 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 width tapering 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 path area to the increase in the piston speed changes in 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 in the low speed region and the high speed region.

In the first damping force generating mechanism 145A of the second embodiment, in a state where the contact disk 115A is in contact with the first outer sheet 61, the protruding plate portion 171 is attached to the first width tapering portion 65 of the first outer sheet 61. Facing in the radial direction. As described above, the first width gradually decreases as compared with the flow path area between the contact disk 115A and the first width gradually decreasing portion 65 when the protrusion plate portion 171 faces the first width gradually decreasing portion 65 in the radial direction. By increasing the flow path area between the contact disk 115A and the first width gradual reduction portion 65 when the protruding plate portion 171 does not face the portion 65 in the radial direction, the damping force increases with respect to the increase in piston speed. The ratio of is lower in the high speed range than in the medium speed range of the piston speed.

Also in this case, the contact disk 115A faces the first outer sheet 61 in the radial direction while being in contact with the first outer sheet 61, and when separated from the first outer sheet 61 by a predetermined amount in the radial direction. Since the protruding plate portion 171 may be provided so as not to face each other, the structure is simple. Moreover, since the protruding plate portion 171 is formed on the contact disk 115A formed by press forming during press forming, an increase in the number of parts can be suppressed, and an increase in cost can be suppressed.

According to the first aspect of the embodiment described above, the shock absorber includes a cylinder in which the working fluid is sealed and a piston that is slidably inserted into the cylinder and defines the inside of the cylinder into two chambers. A piston rod connected to the piston and extending to the outside of the cylinder, a passage through which the working fluid flows due to the sliding of the piston, and a passage provided in the passage to control the flow of the working fluid to control the damping force. It is provided with a damping force generating mechanism for generating. The damping force generating mechanism includes a valve body through which the passage penetrates, a substantially circular outer seat formed in the valve body so as to surround the opening of the passage, and the outer seat in the valve body. It is provided with an inner seat that is formed so as to project inward, and a disk-shaped disc valve that is seated on the outer seat and the inner seat and is seated on the outer peripheral seat at least by bending the outer peripheral side. The outer seat has at least one of an inner peripheral side taper portion in which the inner peripheral side expands toward the seat surface on which the disc valve is seated and an outer peripheral side tapered portion in which the outer peripheral side contracts. The disc valve has at least one of an inner protruding portion that is radially opposed to the inner tapered portion or an outer protruding portion that is radially opposed to the outer tapered portion in a closed state seated on the outer seat. After the disc valve is opened from the closed state, as the valve is opened, the inner protruding portion is between the portions facing the inner peripheral side tapered portion in the radial direction, or the outer protruding portion is the outer periphery. A state in which the flow path area formed between the side tapered portion and the portion facing in the radial direction is smaller than the flow path area formed in the gap between the disc valve and the top of the outer seat. It is characterized by becoming.

In the second aspect, in the first aspect, immediately after the disc valve is closed and the valve opening is started, the inner protruding portion is between the portions facing the inner peripheral side tapered portion in the radial direction, or immediately after the valve opening is started. , The flow path area formed between the portion where the outer protruding portion faces the outer peripheral side tapered portion in the radial direction is formed in the gap between the disc valve and the top of the outer seat. It will be larger than the road area.

In the third aspect, in the first aspect, the disc valve is curved toward the valve body side to form the inner protrusion or the outer protrusion.

In the fourth aspect, in the first aspect, in the disc valve, the inner protruding portion or the outer protruding portion is formed by a thick portion protruding from the surface on the valve body side.

In the fifth aspect, in the fourth aspect, the thick portion is configured by attaching another member to the disc closest to the main body.

In the sixth aspect, in the first aspect, the disc valve is formed of a plurality of discs, and the disc on the main body side is a valve having a diameter smaller than that of the inner tapered portion. Is the inner protruding portion.

According to the above-mentioned shock absorber, the ratio of the increase in the damping force to the increase in the piston speed can be reduced by a simple configuration.

10 Shock absorber 11 Cylinder 12 Piston 13 Piston rod 19 1st chamber 20 2nd chamber 31 Piston body (valve body)
61 First outer sheet (outer sheet)
65 1st width gradual decrease part (width gradual decrease part)
71 First inner sheet (inner sheet)
76 First passage (passage)
77 First opening (opening)
115, 115A Contact disc (disc)
136 Convex part 145, 145A 1st damping force generation mechanism (damping force generation mechanism)
171 protruding plate part (convex part)

Claims (5)

Cylinder in which working fluid is sealed and
A piston that is slidably inserted into the cylinder and defines the inside of the cylinder into two chambers.
A piston rod that is connected to the piston and extends to the outside of the cylinder,
The passage through which the working fluid flows due to the sliding of the piston,
A damping force generating mechanism provided in the passage to control the flow of the working fluid to generate a damping force.
With
The damping force generation mechanism is
The valve body through which the passage penetrates and
A substantially circular outer seat formed on the valve body so as to surround the opening of the passage.
An inner seat formed on the valve body so as to project inside the outer seat,
A disc-shaped disc valve that sits on the outer seat and the inner seat and bends on the outer peripheral side to at least take off and seat on the outer seat.
With
The outer seat has at least one of an inner peripheral side taper portion in which the inner peripheral side expands toward the seat surface on which the disc valve is seated and an outer peripheral side tapered portion in which the outer peripheral side contracts.
The disc valve is arranged so as to be closer to the valve main body than the seating surface of the outer peripheral seat in the closed state when seated on the outer seat, and is close to or abutting the inner tapered portion or at least one of the outer tapered portions. have a collision detecting portion which protrudes so as to be in contact,
The first opening is higher than the rate of increase in the flow rate area with respect to the increase in the valve opening height in the section where the valve opening height of the disc valve increases from the valve closed state to the first valve opening height after the valve opening is started. A shock absorber in which the rate of increase in the flow rate area with respect to the increase in the valve opening height in the section increasing from the valve height to the valve opening second valve opening height is larger than the first valve opening height . The shock absorber according to claim 1, wherein the disc valve has a protruding portion formed by bending toward the valve body side. The shock absorber according to claim 1, wherein the disc valve has a protruding portion formed by a thick portion protruding from a surface on the valve body side. The shock absorber according to claim 3 , wherein the thick portion is formed by attaching another member to the disk closest to the valve body. The disc valve is formed of a plurality of discs, and the disc on the valve body side is a valve having a smaller diameter than the inner peripheral side tapered portion, and the outer peripheral portion of the valve having the smaller diameter is the protruding portion. The shock absorber according to claim 1.

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