Shock absorption device and suspension device

Abstract

To provide a shock absorption device having a damping force generation unit capable of freely setting effectiveness of hydraulic cushioning action.SOLUTION: A shock absorption device 2 comprises a damping force generation unit 190 that is arranged on a second side with respect to a first piston part in a cylinder 11 and generates a damping force that suppresses movement of a rod 20 toward the second side. The damping force generation unit 190 has: a sliding member 110 that can slide against an inner peripheral surface of the cylinder 11; a holding member 130 that holds the sliding member 110 movably over a predetermined range in a center line direction; and an elastic member 120 that applies force to the sliding member 110 in a direction of moving it toward the second side. When the rod 20 moves toward the second side, the elastic member 120 is pressed by the sliding member 110 and deformed, to narrow a flow path of oil passing inside the sliding member 110, and the sliding member 110 has a notch 115 through which oil can flow even when the elastic member 120 is deformed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to shock absorbers and suspension systems. [Background technology]

[0002] Conventionally, a hydraulic shock absorber is provided with a hydraulic stopper mechanism that generates a hydraulic cushioning effect at the time of maximum extension. For example, the hydraulic shock absorber described in Patent Document 1 comprises a second cylinder fixedly provided inside the enlarged diameter portion of the inner cylinder and a second piston provided on the outer periphery of the piston rod, which constitutes a hydraulic stopper mechanism. The second piston has a stopper connected to the piston rod, a castle located above the stopper and integrated by being press-fitted into the inner fitting hole, and a piston ring attached to a ring groove formed by the castle and the castle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-128752 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the damping force generating section (the stopper mechanism in Patent Document 1), it is desirable to be able to freely set the effectiveness of the hydraulic cushioning action. An object of the present invention is to provide a shock absorber or the like having a damping force generating section that can freely set the effectiveness of hydraulic cushioning action. [Means for solving the problem]

[0005] The present invention, which was completed with the above object in mind, comprises a cylinder filled with fluid, a piston portion that is inserted into the cylinder so as to be movable in a center line direction and that partitions the interior of the cylinder, a rod that holds the piston portion on one side in the center line direction and has an end portion on the other side in the center line direction that protrudes outside the cylinder, a damping force generating portion that is disposed on the other side of the piston portion within the cylinder and generates a damping force that suppresses movement of the rod to the other side, and a damping force generating portion that is fixed to the rod and restricts movement of the damping force generating portion to the one side. and a regulating member, wherein the damping force generating portion has a sliding member that is slidable against the inner surface of the cylinder, a holding member that holds the sliding member so that it can move over a predetermined range in the center line direction, and an elastic member that applies a force to the sliding member in a direction that moves it toward the other side, wherein the elastic member is pushed by the sliding member and deforms when the rod moves to the other side, thereby narrowing the flow path of the fluid passing inside the sliding member, and an orifice is formed in the sliding member or the elastic member through which the fluid can flow even when the elastic member is deformed. Effect of the Invention

[0006] According to the present invention, it is possible to provide a shock absorber having a damping force generating section that can freely set the effectiveness of the hydraulic cushioning action. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a suspension device according to a first embodiment. [Diagram 2] 1 is a diagram showing an example of a partial cross section of a suspension device according to a first embodiment. [Diagram 3] 4A to 4C are diagrams illustrating an example of the appearance of a second piston portion according to the first embodiment. [Figure 4] 5A to 5C are diagrams showing an example of a state in which a second piston portion according to the first embodiment is assembled. [Diagram 5] 11A and 11B are diagrams illustrating an example of a state of a second piston portion during extension. [Figure 6]6A and 6B are diagrams illustrating an example of a state of a second piston portion during compression. [Figure 7] 13 is a diagram showing an example of a partial cross section of a damping force generating portion according to a second embodiment. FIG. [Figure 8] 13 is a diagram showing an example of the appearance of a second piston portion according to a second embodiment. FIG. [Figure 9] 13A and 13B are diagrams showing an example of a state in which a second piston portion according to a second embodiment is assembled. [Figure 10] 11A and 11B are diagrams illustrating an example of a state of a second piston portion during extension. [Figure 11] 6A and 6B are diagrams illustrating an example of a state of a second piston portion during compression. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First Embodiment FIG. 1 is a diagram showing an example of a schematic configuration of a suspension device 1 according to the first embodiment. FIG. 2 is a diagram showing an example of a partial cross section of the suspension device 1 according to the first embodiment. FIG. 3 is a diagram showing an example of the appearance of the second piston portion 100 according to the first embodiment. FIG. 4 is a diagram showing an example of a state in which the second piston portion 100 according to the first embodiment is assembled.

[0009] The suspension system 1 is a suspension used in four-wheeled vehicles such as passenger automobiles, and as shown in Fig. 1, includes a hydraulic shock absorber 2 and a coil spring 3 arranged on the outside of the shock absorber 2. The suspension system 1 also includes a lower spring sheet 4 that supports an end of the coil spring 3 on a first axial side (lower side in Fig. 1) of a rod 20 described below, and an upper spring sheet 5 that supports an end of the coil spring 3 on a second axial side (upper side in Fig. 1) of the rod 20.

[0010] The suspension device 1 also includes a vehicle body side bracket 6 for mounting the suspension device 1 to a vehicle, a wheel side bracket 7 for mounting the suspension device 1 to a wheel, and a dust cover 8 that covers at least a portion of the cylinder portion 10 and the rod 20. Hereinafter, the axial direction of the rod 20 may be simply referred to as the "axial direction." Since the rod 20 moves in the direction of the center line of the cylinder 11 described later, the axial direction is also the direction of the center line of the cylinder 11. Also, the first side in the axial direction (lower side in FIG. 1) and the second side in the axial direction (upper side in FIG. 1) may be simply referred to as the "first side" and the "second side," respectively. Also, the direction intersecting the axial direction (for example, the perpendicular direction) may be simply referred to as the "radial direction." In the radial direction, the side of the center line of the cylinder 11 may be simply referred to as the "inner side," and the side away from the center line may be simply referred to as the "outer side."

[0011] The shock absorber 2 will be described in detail below. The shock absorber 2 includes a cylinder portion 10 that contains oil, and a rod 20 whose second end protrudes from the cylinder portion 10 and whose first end is inserted into the cylinder portion 10. The shock absorber 2 also includes a first piston portion 30 that is provided at the first end of the rod 20, and a bottom portion 40 that is provided at the first end of the cylinder portion 10. The shock absorber 2 also includes a second piston portion 100 that absorbs impact when the rod 20 extends, and a spring 170 that holds the second piston portion 100.

[0012] The cylinder portion 10 has a cylinder 11 that contains oil, and an outer cylinder body 12 that is provided on the outside of the cylinder 11. The cylinder portion 10 also includes a rod guide portion 60 that movably supports the rod 20, a bump stopper cap 15 that is attached to the second end of the outer cylinder body 12, and an oil seal 16 that prevents oil from leaking from within the cylinder portion 10 and prevents foreign matter from entering the cylinder portion 10. In the cylinder portion 10, an outer circumferential surface of the cylinder 11 and an inner circumferential surface of the outer cylinder body 12 form a reservoir chamber R.

[0013] The cylinder 11 is formed with a groove 11g shown in FIG. 2. When viewed in the axial direction, the groove 11g is formed in an arc shape, and the cross-sectional area in a cross section cut along a plane perpendicular to the axial direction gradually decreases toward the second axial side. The manner in which the cross-sectional area is changed is not particularly limited. For example, the radial size (in other words, depth) of the groove 11g may be changed, or the circumferential size (in other words, width) of the groove 11g may be changed. In addition, the radial size of the groove 11g and the circumferential size of the groove 11g may be changed. Note that a plurality of grooves 11g may be formed in the circumferential direction, or there may be only one groove 11g.

[0014] The rod 20 is a rod-shaped member that extends long in the axial direction. The rod 20 holds the first piston portion 30 on a first side. The rod 20 is connected to, for example, a vehicle body via a vehicle body-side bracket 6 on a second side. The rod 20 also has a fixed member 25 fixed to the rod 20, and a cylindrical rebound rubber 26. The fixed member 25 is made of iron, and is fixed to the rod 20 by welding or the like. The fixed member 25 has a cylindrical portion that covers the periphery of the rod 20, and a disk-shaped portion that protrudes outward from the end of the cylindrical portion on the second side. The rebound rubber 26 is an elastic member made of rubber or the like, and is disposed on the second side of the disk-shaped portion of the fixed member 25.

[0015] The first piston portion 30 includes a piston 31, a valve group 32 that blocks first ends of some of the oil passages formed in the piston 31, and a valve group 33 that blocks second ends of some of the oil passages formed in the piston 31. The piston 31 contacts the inner surface of the cylinder 11 via a sealing member provided on its outer surface, and divides the space inside the cylinder 11 filled with oil into a first chamber Y1 on the first side of the piston 31 and a second chamber Y2 on the second side of the piston 31.

[0016] As shown in FIG. 1, the bottom portion 40 includes a valve body 41 having a plurality of oil passages penetrating in the axial direction, a valve 42 provided on a first side of the valve body 41, and a valve 43 provided on a second side of the valve body 41. The valve body 41 of the bottom portion 40 separates the first chamber Y1 and the reservoir chamber R.

[0017] The rod guide portion 60 includes a thin-walled cylindrical guide 61 disposed inside, and a guide case 70 that holds the guide 61 inside. The guide 61 is made of a material that is more wear-resistant than the guide case 70 .

[0018] The guide case 70 has a cylindrical inner cylindrical portion 71 provided on the inside, and a cylindrical outer cylindrical portion 72 provided on the outside of the inner cylindrical portion 71. The inner cylindrical portion 71 and the outer cylindrical portion 72 are integrally molded such that the outer peripheral surface of the second side portion of the inner cylindrical portion 71 and the inner peripheral surface of the first side portion of the outer cylindrical portion 72 are continuous.

[0019] The guide 61 is fitted inside the inner cylindrical portion 71. The outer diameter of the inner cylindrical portion 71 is formed to be smaller than the inner diameter of the cylinder 11, and the inner cylindrical portion 71 is disposed inside the cylinder 11. The outer cylindrical portion 72 is disposed between the rod 20 and the outer cylinder body 12 on the second side of the cylinder 11. The outer diameter of the outer cylindrical portion 72 is smaller than the inner diameter of the end of the outer cylinder body 12 on the second side.

[0020] The inner cylindrical portion 71 has a protruding portion 711 that protrudes cylindrically from the end face of the first side at an inner portion. The inner diameter of the protruding portion 711 is larger than the outer diameter of the guide 61. The outer diameter of the protruding portion 711 is larger than the inner diameter of the spring 170, and the protruding portion 711 is press-fitted into the inside of the spring 170. The guide case 70 has the protruding portion 711 inserted into the inside of the spring 170 until the end face of the second side of the inner cylindrical portion 71 contacts the end of the second side of the spring 170. The axial length of the protruding portion 711 is larger than the length of a second end turn portion 172 of the spring 170, which will be described later. In this manner, the guide case 70 holds the end of the second side of the spring 170.

[0021] Spring 170 is a coil spring and has a first winding seat portion 171 which is a winding seat portion formed at an end on a first side, a second winding seat portion 172 which is a winding seat portion formed at an end on a second side, and an expansion / contraction portion 173 which is provided between first winding seat portion 171 and second winding seat portion 172 and which expands and contracts.

[0022] [Second piston portion 100] The second piston portion 100 includes a sliding member 110 that is slidable against the inner circumferential surface of the cylinder 11, an elastic member 120 that is elastically deformable upon receiving a force from the sliding member 110, and a holding member 130 that holds the sliding member 110 and the elastic member 120. For example, the sliding member 110 and the holding member 130 are molded from a metal or a resin, and the elastic member 120 is molded from a metal.

[0023] The sliding member 110 is an annular member having a rectangular cross-sectional shape when cut along a plane parallel to the axial direction, and has a first surface 111 which is a surface on the first side, a second surface 112 which is a surface on the second side, an outer peripheral surface 113, and an inner peripheral surface 114. The first surface 111 and the second surface 112 are surfaces perpendicular to the axial direction, and the outer peripheral surface 113 and the inner peripheral surface 114 are surfaces parallel to the axial direction. The diameter of the outer peripheral surface 113 is the same as the inner diameter of the cylinder 11, making it difficult for oil to flow between the outer peripheral surface 113 and the inner peripheral surface of the cylinder 11. The radius of the inner peripheral surface 114 is greater than the distance to the deepest part of a recess 155 in the holding member 130, which will be described later.

[0024] When the outer peripheral surface 113 comes into contact with the inner peripheral surface of the cylinder 11, the second piston portion 100 divides the second chamber Y2 into a third chamber Y3 on the first side of the sliding member 110 and a fourth chamber Y4 on the second side of the sliding member 110. A notch 115 recessed toward the second side is formed in a part of the circumferential direction over the entire radial area from the first surface 111 in the sliding member 110. A plurality of notches 115 may be formed in the circumferential direction, or there may be only one notch 115.

[0025] The elastic member 120 can be, for example, a disk spring formed into a cone shape. The inner diameter of the elastic member 120 is larger than the outer diameter of a second cylindrical portion 152 (described later) in the holding member 130, and the outer diameter is smaller than the inner diameter of the cylinder 11. The elastic member 120 is disposed so that the diameter gradually increases from the first side to the second side.

[0026] The holding member 130 has a first member 140 disposed on a first side, and a second member 150 disposed on a second side and connected to the first member 140. The first member 140 is an annular member having a rectangular cross-sectional shape when cut along a plane parallel to the axial direction. The inner portion of the first member 140 has a tapered portion 142 whose diameter gradually increases from the diameter of the inner peripheral surface 141 as it moves from the second side to the first side. The outer diameter of the first member 140 is smaller than the inner diameter of the cylinder 11 and the diameter of the outer peripheral surface 113 of the sliding member 110. The first member 140 has a recess 143 recessed inward from the outer peripheral surface formed in a part of the circumferential direction. Five recesses 143 are formed at equal intervals in the circumferential direction. However, the number of recesses 143 is not limited to five. When viewed in the axial direction, the recess 143 can be exemplified as being semicircular.

[0027] The second member 150 is a member in which four cylindrical portions, a first cylindrical portion 151, a second cylindrical portion 152, a third cylindrical portion 153, and a fourth cylindrical portion 154, are arranged in the axial direction from the first side to the second side. The first cylindrical portion 151 is inclined with respect to the axial direction so that the outer surface thereof follows the inner surface of the tapered portion 142 of the first member 140. The first cylindrical portion 151 is formed so as to follow the inner surface of the tapered portion 142 by applying force to the cylindrical portion.

[0028] The second cylindrical portion 152, the third cylindrical portion 153, and the fourth cylindrical portion 154 are cylindrical portions having the same inner diameter but different outer diameters. The inner diameter is larger than the outer diameter of the rod 20, and the outer diameters are larger in the order of the third cylindrical portion 153, the second cylindrical portion 152, and the fourth cylindrical portion 154. The outer diameter of the second cylindrical portion 152 is larger than the diameter of the inner circumferential surface 141 of the first member 140, and the end face on the first side of the second cylindrical portion 152 is in contact with the end face on the second side of the first member 140. In addition, the outer diameter of the second cylindrical portion 152 is smaller than the diameter of the inner circumferential surface 114 of the sliding member 110.

[0029] The outer diameter of the third cylindrical portion 153 is smaller than the inner diameter of the cylinder 11 and the diameter of the outer peripheral surface 113 of the sliding member 110. The third cylindrical portion 153 has recesses 155 recessed inward from the outer peripheral surface formed in a part of the circumferential direction. In the example shown in FIG. 3, five recesses 155 are formed at equal intervals in the circumferential direction. However, the number of recesses 155 is not limited to five. When viewed in the axial direction, the recesses 155 are semicircular, and the distance from the center line to the deepest part 156 from the outer peripheral surface is smaller than the radius of the inner peripheral surface 114 of the sliding member 110.

[0030] The outer diameter of the fourth cylindrical portion 154 is larger than the inner diameter of the spring 170, and the fourth cylindrical portion 154 is press-fitted into the inside of the spring 170. The holding member 130 has the fourth cylindrical portion 154 inserted into the inside of the spring 170 until the end face on the second side of the third cylindrical portion 153 comes into contact with the end of the first side of the spring 170. The axial length of the fourth cylindrical portion 154 is larger than the length of the first end turn portion 171 of the spring 170. In this manner, the holding member 130 is held at the end of the spring 170 on the first side.

[0031] 4, the second piston portion 100 is connected to the first member 140 by crimping the second member 150. That is, the first tubular portion 151 of the second member 150 is cylindrical before being crimped, and after the second tubular portion 152 of the second member 150 is passed through the inside of the sliding member 110 and the elastic member 120 and the first tubular portion 151 is passed through the inside of the first member 140, a force is applied to the cylindrical portion, so that the cylindrical portion is deformed to fit along the inner surface of the tapered portion 142 of the first member 140. As a result, the first member 140, the second member 150, the sliding member 110, and the elastic member 120 are integrated. The first member 140 and the second member 150 are crimped so that the circumferential position of the recess 143 of the first member 140 and the circumferential position of the recess 155 of the second member 150 coincide with each other.

[0032] The second piston portion 100 moves in the axial direction relative to the cylinder 11. Moreover, the axial size between the first member 140 and the third cylindrical portion 153 of the second member 150 is larger than the axial size of the sliding member 110 and the elastic member 120. Therefore, the sliding member 110 and the elastic member 120 are held by the first member 140 and the second member 150 so as to be movable over a predetermined range between the first member 140 and the third cylindrical portion 153 of the second member 150.

[0033] In the shock absorber 2 configured as above, when the rod 20 extends and the amount of protrusion from the cylinder portion 10 increases, the fixed member 25 comes into contact with the rebound rubber 26 and the first member 140 of the second piston portion 100 comes into contact with the rebound rubber 26. When the amount of protrusion of the rod 20 from the cylinder portion 10 increases further, the spring 170 contracts. The contraction of the rebound rubber 26 and the spring 170 absorbs the impact when, for example, there is a dent in the road surface on which the vehicle is traveling and the amount of protrusion of the rod 20 suddenly increases.

[0034] In the shock absorber 2, the above-mentioned cylinder 11, the second piston portion 100, etc. constitute a damping force generating portion 190 that generates a damping force so as to reduce the impact during extension. The operation of the damping force generating portion 190 will be described below. (When extended) FIG. 5 is a diagram showing an example of a state of the second piston portion 100 during extension. When the amount of protrusion of the rod 20 from the cylinder portion 10 increases, as shown in FIG. 5, the pressure in the fourth chamber Y4 becomes higher than the pressure in the third chamber Y3, and the sliding member 110 moves to the first side relative to the holding member 130, elastically deforming the elastic member 120. As a result, the adhesion force between the sliding member 110 and the elastic member 120 and the adhesion force between the elastic member 120 and the first member 140 increases, and the oil becomes less likely to flow from the fourth chamber Y4 to the third chamber Y3 through the gap formed between the inner circumferential surface 114 of the sliding member 110 and the outer circumferential surface of the second cylindrical portion 152 of the holding member 130. At this time, the oil flows out to the third chamber Y3 through the notch 115 formed in the sliding member 110. This generates a damping force.

[0035] Furthermore, when the amount of protrusion of the rod 20 from the cylinder portion 10 increases and the pressure in the fourth chamber Y4 becomes higher than the pressure in the third chamber Y3, the oil flows out into the third chamber Y3 through the groove 11g formed in the cylinder 11. This generates a damping force. The cross-sectional area, in other words, the flow path area, of the groove 11g decreases toward the second axial side, so that the damping force by the groove 11g increases as the amount of protrusion of the rod 20 from the cylinder portion 10 increases.

[0036] (When compressed) FIG. 6 is a diagram showing an example of a state of the second piston portion 100 during compression. During compression, when the amount of protrusion of the rod 20 from the cylinder portion 10 decreases from the contracted state of the spring 170, the spring 170 expands, moving the second piston portion 100 to the first side. When the amount of protrusion of the rod 20 from the cylinder portion 10 decreases and the pressure in the fourth chamber Y4 becomes lower than the pressure in the third chamber Y3, the sliding member 110 moves to the second side relative to the holding member 130, and oil flows from the third chamber Y3 to the fourth chamber Y4 through the gap between the sliding member 110 and the elastic member 120 or the gap between the elastic member 120 and the first member 140, the gap between the inner peripheral surface 114 of the sliding member 110 and the outer peripheral surface of the second cylindrical portion 152 of the holding member 130, and the recess 155 of the third cylindrical portion 153.

[0037] As described above, the shock absorber 2 includes the cylinder 11 filled with oil as an example of a fluid, and the first piston portion 30 inserted movably in the center line direction (in other words, the axial direction) of the cylinder 11 and partitioning the inside of the cylinder 11. The shock absorber 2 also includes a rod 20 that holds the first piston portion 30 on a first side in the axial direction (an example of one side in the center line direction) and has an end portion on a second side in the axial direction (an example of the other side in the center line direction) protruding out of the cylinder 11. The shock absorber 2 also includes a damping force generating portion 190 that is disposed on the second side of the first piston portion 30 in the cylinder 11 and generates a damping force that suppresses movement of the rod 20 toward the second side, and a fixed member 25 that is fixed to the rod 20 and serves as an example of a restricting member that restricts movement of the damping force generating portion 190 toward the first side. The damping force generating unit 190 includes a sliding member 110 that is slidable against the inner circumferential surface of the cylinder 11, a holding member 130 that holds the sliding member 110 movably over a predetermined range in the axial direction, and an elastic member 120 that applies a force to the sliding member 110 in a direction that moves the sliding member 110 toward the second side. When the rod 20 moves toward the second side, the elastic member 120 is pressed by the sliding member 110 and deforms, thereby narrowing the flow path of the fluid passing inside the sliding member 110. The sliding member 110 is formed with a notch 115 as an example of an orifice through which oil flows even when the elastic member 120 is deformed.

[0038] In the shock absorber 2 configured as described above, when the rod 20 is extended and the amount of protrusion from the cylinder portion 10 increases, a damping force is generated by oil flowing from the fourth chamber Y4 to the third chamber Y3 through the notches 115 formed in the sliding member 110. By changing the size and number of the notches 115, the flow path area of ​​the oil flowing through the notches 115 can be changed, so that the damping force can be freely set.

[0039] In the shock absorber 2, a groove 11g is formed in the cylinder 11, which extends in the center line direction and protrudes outward from the inner circumferential surface. Therefore, when the amount of protrusion of the rod 20 from the cylinder portion 10 increases and the pressure in the fourth chamber Y4 becomes higher than the pressure in the third chamber Y3, oil flows from the fourth chamber Y4 to the third chamber Y3 through the groove 11g, generating a damping force. By changing the size and number of the groove 11g, the flow path area of ​​the oil flowing through the groove 11g can be changed, so that the damping force can be freely set.

[0040] The shock absorber 2 further includes a rod guide portion 60 (an example of a support member) that is fitted into the end portion on the second side in the axial direction of the cylinder 11 and supports the rod 20, and a coil spring 170 that has one end supported by the holding member 130 and the other end supported by the rod guide portion 60. Therefore, as the spring 170 contracts, the amount of protrusion of the rod 20 increases, and the second piston portion 100 moves to the first side during compression after the rod 20 is compressed, so that a damping force can be generated with high certainty during the subsequent extension. The spring 170 can also reduce rebound shock.

[0041] The holding member 130 is cylindrical, and has a second cylindrical portion 152 recessed from the outer circumferential surface all around in a predetermined range (in other words, a range corresponding to the axial size of the second cylindrical portion 152), and the sliding member 110 is fitted into the recess. As a result, the holding member 130 holds the sliding member 110 movably over a predetermined range in the axial direction.

[0042] A recess 155 recessed from the outer circumferential surface is formed in a part of the circumferential direction on the second side of the second cylindrical portion 152 of the holding member 130 so that the distance from the center line is smaller than the radius of the inner circumferential surface 114 of the sliding member 110. This makes it possible to ensure a flow path for oil to flow from the third chamber Y3 to the fourth chamber Y4 even if the second surface 112 of the sliding member 110 contacts the third cylindrical portion 153 of the holding member 130 during compression.

[0043] The elastic member 120 is not limited to a disc spring, and may be a wave washer, a spring washer, or an annular leaf spring with legs. In the above-described embodiment, even when the elastic member 120 is deformed by being pushed by the sliding member 110 during extension, the notch 115 of the sliding member 110 functions as an orifice that generates a damping force, but the functioning as an orifice is not limited to the notch 115 of the sliding member 110. Instead of forming the notch 115 in the sliding member 110, or in addition to forming the notch 115 in the sliding member 110, for example, a through hole or a slit formed in the elastic member 120 may function as an orifice. In addition, when the elastic member 120 is a spring washer, a gap between one end and the other end of the spring washer may function as an orifice.

[0044] <Second embodiment> FIG. 7 is a diagram showing an example of a partial cross section of a damping force generating section 290 according to the second embodiment. FIG. 8 is a diagram showing an example of the appearance of the second piston portion 200 according to the second embodiment. FIG. 9 is a diagram showing an example of a state in which the second piston portion 200 according to the second embodiment is assembled. A damping force generating section 290 according to the second embodiment differs from the damping force generating section 190 according to the first embodiment in that it has a second piston section 200 that corresponds to the second piston section 100. The second piston section 200 differs from the second piston section 100 in that it has an elastic member 220 that corresponds to the elastic member 120 and a retaining member 230 that corresponds to the retaining member 130. The following describes the differences from the first embodiment. The same reference numerals are used for the same parts in the first and second embodiments, and detailed descriptions thereof will be omitted.

[0045] The holding member 230 is different from the holding member 130 in that a first member 240 corresponds to the first member 140 . The first member 240 differs from the first member 140 in that a circularly recessed recess 242 is formed in the second surface 241, which is the end surface on the second side, and in that the first member 240 has a cylindrical protrusion 243 protruding from the recess 242 on the outer periphery. The diameter of the outer periphery of the second surface 241 is the same as the outer diameter of the second cylindrical portion 152 of the second member 150, and the second surface 241 is formed in an area facing the first end face of the second cylindrical portion 152. The recess 242 is formed on the outer side of the second surface 241 . The cross section of the protruding portion 243 taken along a plane parallel to the axial direction is rectangular. The axial size of the protruding portion 243 from the bottom surface of the recessed portion 242 is half the axial size from the bottom surface of the recessed portion 242 to the second surface 241, and the axial size of the protruding portion 243 and the radial size of the protruding portion 243 are equal to each other.

[0046] The elastic member 220 is an annular leaf spring. The inner diameter of the elastic member 220 is equal to the inner diameter of the second surface 241 of the first member 240, and the outer diameter of the elastic member 220 is equal to the diameter of the outer circumferential surface of the first member 240. The elastic member 220 is assembled in a state in which an inner portion is sandwiched between the second surface 241 of the first member 240 and the end surface of the first side of the second cylindrical portion 152 of the second member 150. As a result, the inner portion of the elastic member 220 functions as a fixed end, and the outer portion functions as a working end. Further, in the elastic member 220, a cylindrical through hole 221 is formed in a part in the circumferential direction outside the inner part sandwiched between the first member 240 and the second member 150. For example, a plurality of through holes 221 are formed in the circumferential direction.

[0047] The operation of the damping force generating section 290 will be described below. (When extended) FIG. 10 is a diagram showing an example of a state of the second piston portion 200 during extension. When the amount of protrusion of the rod 20 from the cylinder portion 10 increases, the pressure in the fourth chamber Y4 becomes higher than the pressure in the third chamber Y3, and the sliding member 110 moves to the first side relative to the holding member 230, elastically deforming the elastic member 220, and the outer periphery of the elastic member 220 comes into contact with the protruding portion 243 of the first member 240 of the holding member 230. As a result, the adhesion force between the sliding member 110 and the elastic member 220 and the adhesion force between the elastic member 220 and the first member 240 increases, and the oil becomes less likely to flow from the fourth chamber Y4 to the third chamber Y3 through the gap formed between the inner circumferential surface 114 of the sliding member 110 and the outer circumferential surface of the second cylindrical portion 152 of the holding member 230. At this time, the oil flows out to the third chamber Y3 through the notch 115 formed in the sliding member 110. This generates a damping force. Also, as in the first embodiment, when the amount of protrusion of the rod 20 from the cylinder portion 10 increases and the pressure in the fourth chamber Y4 becomes higher than the pressure in the third chamber Y3, a damping force is generated by the oil passing through the groove 11g formed in the cylinder 11.

[0048] (When compressed) FIG. 11 is a diagram showing an example of a state of the second piston portion 200 during compression. When the amount of protrusion of the rod 20 from the cylinder portion 10 decreases from the contracted state of the spring 170, the spring 170 expands, moving the second piston portion 200 to the first side. When the amount of protrusion of the rod 20 from the cylinder portion 10 decreases and the pressure in the fourth chamber Y4 becomes lower than the pressure in the third chamber Y3, the sliding member 110 moves to the second side relative to the holding member 230, and oil flows from the third chamber Y3 to the fourth chamber Y4 through the gap between the inner circumferential surface 114 of the sliding member 110 and the outer circumferential surface of the second cylindrical portion 152 of the holding member 230. 11, the oil flows from the third chamber Y3 to the fourth chamber Y4 through the gap between the elastic member 220 and the first member 240, the through hole 221 of the elastic member 220, the gap between the inner circumferential surface 114 of the sliding member 110 and the outer circumferential surface of the second cylindrical portion 152 of the holding member 230, and the recessed portion 155 of the third cylindrical portion 153. Alternatively, the oil flows from the third chamber Y3 to the fourth chamber Y4 through the gap between the sliding member 110 and the elastic member 220, the gap between the inner circumferential surface 114 of the sliding member 110 and the outer circumferential surface of the second cylindrical portion 152 of the holding member 230, and the recessed portion 155 of the third cylindrical portion 153.

[0049] Thus, in the second piston portion 200, when the rod 20 moves to the second side (when extended), the sliding member 110 moves to the first side to elastically deform the elastic member 220 and close the flow path of oil passing through the gap between the elastic member 220 and the first member 240 of the holding member 230. On the other hand, when the rod 20 moves to the first side (when compressed), the sliding member 110 moves to the second side to allow the elastic member 220 to return from elastic deformation and open the flow path of oil passing through the gap between the elastic member 220 and the first member 240 of the holding member 230. In other words, the second piston portion 200 has a check valve mechanism composed of the sliding member 110, the elastic member 220, and the holding member 230.

[0050] In the damping force generating section 290 configured as above, the flow path area of ​​the oil flowing through the notches 115 can be changed by changing the size and number of the notches 115, so that the damping force can be set freely. Also, the flow path area of ​​the oil flowing through the grooves 11g can be changed by changing the size and number of the grooves 11g of the cylinder 11, so that the damping force can be set freely.

[0051] In the second piston portion 200, the retaining member 230 has a first member 240 arranged on the first side and a second member 150 arranged on the second side and connected to the first member 240, and the elastic member 220 is fixed by having its inner periphery sandwiched between the first member 240 and the second member 150. This makes it possible to realize a check valve mechanism with a simple configuration. [Explanation of symbols]

[0052] Reference Signs List 1...suspension device, 2...shock absorber, 3...coil spring, 10...cylinder portion, 11...cylinder, 11g...groove, 20...rod, 25...fixing member (an example of a restricting member), 26...rebound rubber, 30...first piston portion (an example of a piston portion), 60...rod guide portion (an example of a supporting member), 100, 200...second piston portion, 170...spring, 110...sliding member, 115...notch (an example of an orifice), 120, 220...elastic member, 130, 230...holding member, 190, 290...damping force generating portion

Claims

1. A cylinder containing a fluid; a piston portion that is inserted movably in a center line direction of the cylinder and that defines an interior of the cylinder; a rod that holds the piston portion on one side in the center line direction and has an end on the other side in the center line direction protruding outside the cylinder; a damping force generating section that is disposed on the other side of the piston portion in the cylinder and generates a damping force that suppresses movement of the rod toward the other side; a restricting member fixed to the rod and configured to restrict movement of the damping force generating portion to the one side; Equipped with The damping force generating unit has a sliding member that is slidable against the inner circumferential surface of the cylinder, a holding member that holds the sliding member movably over a predetermined range in the center line direction, and an elastic member that applies a force to the sliding member in a direction in which it moves to the other side, and when the rod moves to the other side, the elastic member is pressed by the sliding member and deforms to narrow the flow path of the fluid passing through the inside of the sliding member, and an orifice through which the fluid flows even when the elastic member is deformed is formed in the sliding member or the elastic member. Buffer device.

2. The cylinder has a groove formed therein, the groove protruding outward from the inner circumferential surface and extending in the direction of the center line. The shock absorber according to claim 1 .

3. The groove has a cross-sectional area, when cut along a plane perpendicular to the center line direction, that changes in the center line direction. The shock absorber according to claim 2.

4. a support member fitted into the other end of the cylinder and supporting the rod; a coil spring having one end supported by the holding member and the other end supported by the support member; The shock absorber of claim 1 .

5. The orifice is a notch formed in a portion of the sliding member facing the elastic member. The shock absorber according to claim 1 .

6. The elastic member is a disc spring or a wave washer. The shock absorber according to claim 1 .

7. the elastic member is a spring washer, The orifice is a gap in the spring washer. The shock absorber according to claim 1 .

8. A cylinder containing a fluid; a piston portion that is inserted movably in a center line direction of the cylinder and that defines an interior of the cylinder; a rod that holds the piston portion on one side in the center line direction and has an end on the other side in the center line direction protruding outside the cylinder; a damping force generating section that is disposed on the other side of the piston portion in the cylinder and generates a damping force that suppresses movement of the rod toward the other side; a restricting member fixed to the rod and configured to restrict movement of the damping force generating portion to the one side; Equipped with The damping force generating section includes a sliding member that is slidable against an inner peripheral surface of the cylinder, a holding member that holds the sliding member movably over a predetermined range in the center line direction, and an elastic member that is pushed by the sliding member moving to one side when the rod moves to the other side, deforms to close the flow path of the fluid passing inside the sliding member, and returns to its original shape to open the flow path when the rod moves to the one side. Buffer device.

9. The cylinder has a groove formed therein, the groove protruding outward from the inner circumferential surface and extending in the direction of the center line. The shock absorber according to claim 8.

10. The groove has a cross-sectional area, when cut along a plane perpendicular to the center line direction, that changes in the center line direction. The shock absorber according to claim 9.

11. a support member fitted into the other end of the cylinder and supporting the rod; a coil spring having one end supported by the holding member and the other end supported by the support member; The shock absorber of claim 8 .

12. The elastic member is an annular leaf spring. The shock absorber according to claim 8.

13. A shock absorber according to any one of claims 1 to 12; A coil spring disposed around the shock absorber; A suspension device comprising:

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