Buffer device, suspension device

Abstract

To provide a technology which can achieve an improvement of riding comfort in a high-speed region of a piston speed and an improvement of operation stability in a low-speed region at the same time.SOLUTION: A groove 39 which is annularly recessed from a first outer round part 37 is formed in a piston 31. A plurality of laminates which are arranged such that they are supported on the piston 31 at internal peripheral sides and their external peripheral sides are free ends, include a first laminate 101 seated on the first outside round part 37, a second laminate 102 arranged on a side opposite to the piston 31 with respect to the first laminate 101, and a third laminate 103 arranged on a side opposite to the second laminated 102. The second laminate 102 has a recess which is formed in an external peripheral part and partially warps the first laminate 101 when pressure in a second oil chamber is higher than a pressure in a first oil chamber, and a ring 142 which warps the third laminate 103 so that an external peripheral part is located on the side opposite to an internal peripheral part when there is no pressure difference occurring between the first oil chamber and the second oil chamber.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a shock absorber and a suspension device.

Background Art

[0002] For example, the valve structure of the shock absorber described in Patent Document 1 is configured as follows. That is, a partitioning member including a valve member formed of an annular elastic plate and supported on its inner peripheral side or outer peripheral side, and a valve seat that receives the free end side of the valve member partitions the inside of the cylinder into two oil chambers, and a damping flow path is formed by the deflection of the valve member according to the pressure difference between these two oil chambers, so that a damping force acts on the reciprocating motion of the piston rod with respect to the cylinder. And in this valve structure, the valve member is configured by stacking a sub-valve, an intermediate sheet, and a main valve that form an annular elastic plate with the same inner and outer diameters from the valve seat side, and the seat surface of the valve seat is made circular and abutted against the sub-valve. Further, the intermediate sheet is formed with a notch portion that is fan-shaped and opened at its free end side and partially deflects the sub-valve, and is characterized in that the sub-valve opens from a portion corresponding to the notch portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the shock absorber described in Patent Document 1, there is room for improvement in improving the ride comfort of the vehicle when the piston speed is in the high-speed region and improving the handling stability of the vehicle when the piston speed is in the low-speed region. An object of the present invention is to provide a shock absorber and the like that can achieve both an improvement in ride comfort in a high-speed region of the piston speed and an improvement in handling stability in a low-speed region. [Means for solving the problem]

[0005] The present invention, completed with the above objective, comprises a piston that divides an oil chamber in a cylinder containing hydraulic fluid into a first oil chamber and a second oil chamber, and a plurality of laminates arranged on the piston such that their inner circumference is supported and their outer circumference is a free end, and which are elastically deformable when the pressure in the second oil chamber becomes higher than the pressure in the first oil chamber, and which are stacked in the direction of the centerline of the cylinder, wherein the piston has an annular groove recessed from the seating surface on the first oil chamber side and a communication passage connecting the groove and the second oil chamber, and the plurality of laminates are the piston The shock absorber comprises a first laminate seating on the seating surface of a stone, a second laminate positioned on the opposite side of the piston from the first laminate, and a third laminate positioned on the opposite side of the second laminate, wherein the second laminate has a recess formed on its outer circumference that partially flexes the first laminate when the pressure in the second oil chamber becomes higher than the pressure in the first oil chamber, and a convex portion that flexes the third laminate so that its outer circumference is positioned on the opposite side of its inner circumference when there is no pressure difference between the first and second oil chambers. [Effects of the Invention]

[0006] According to the present invention, it is possible to achieve both improved ride comfort in the high-speed range and improved handling stability in the low-speed range. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example of a schematic configuration of a suspension system according to the first embodiment. [Figure 2] This is a diagram showing an example of the general configuration of the piston section. [Figure 3] This figure shows an example of the piston as viewed axially from the second side. [Figure 4] This figure shows an example of a piston viewed axially from the first side. [Figure 5]This figure shows an example of a partial perspective view of the components that make up the piston. [Figure 6] This is an example of a diagram showing the third valve in the axial direction. [Figure 7] This is an example of a diagram showing the fourth valve in the axial direction. [Figure 8] This figure shows an example of the damping force characteristics of a shock absorber. [Figure 9] This figure shows an example of a third valve relating to the first modified example. [Figure 10] This figure shows an example of a third valve relating to the second modified example. [Figure 11] This figure shows an example of a third valve relating to the third modified example. [Figure 12] This figure shows an example of the fourth valve according to the first modified example, viewed axially from the first side. [Figure 13] This figure shows an example of the fourth valve according to the second modified example, viewed axially from the first side. [Figure 14] This is a partial cross-sectional view showing an example of a fourth valve relating to the second modified example. [Figure 15] This figure shows an example of the schematic configuration of the second laminate of the extension-side damping valve group according to the second embodiment, as viewed axially from the first side. [Figure 16] This figure shows an example of a protrusion related to the first modified example. [Figure 17] This figure shows an example of a protrusion related to the second modified example. [Figure 18] This figure shows an example of a schematic configuration of the second laminate according to the third embodiment. [Figure 19] This figure shows an example of the schematic configuration of the second laminate according to the fourth embodiment, as viewed from the second side in the axial direction. [Figure 20] This figure shows an example of the schematic configuration of the second laminate according to the fifth embodiment, as viewed axially from the first side. [Figure 21] This figure shows an example of the schematic configuration of the second laminate according to the sixth embodiment, viewed axially from the first side, and a figure showing an example of the schematic configuration of the third valve, viewed axially.

Best Mode for Carrying Out the Invention

[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. The suspension device 1 is a strut type suspension used for a four-wheeled vehicle such as a passenger car. As shown in FIG. 1, it includes a hydraulic shock absorber 2 and a coil spring 3 disposed outside the shock absorber 2. Further, the suspension device 1 includes a lower spring seat 4 that supports an end portion of the coil spring 3 on the first side (lower side in FIG. 1) in the axial direction of a rod 20 described later, and an upper spring seat that supports an end portion of the coil spring 3 on the second side (upper side in FIG. 1) in the axial direction of the rod 20.

[0009] In addition, the suspension device 1 includes a vehicle body side bracket 6 attached to an end portion on the second side in the axial direction of the rod 20 for attaching the suspension device 1 to the vehicle, and a wheel side bracket 7 fixed to an end portion on the first side in the axial direction of the rod 20 in a cylinder portion 10 described later for attaching the suspension device 1 to a wheel. Further, the suspension device 1 includes a dust cover 8 that covers at least a part of the cylinder portion 10 and the rod 20.

[0010] Hereinafter, the axial direction of the rod 20 may be simply referred to as the "axial direction". The axial direction is also the center line direction of a cylindrical cylinder 11 described later. In the axial direction, the first side (lower side in FIG. 1) and the second side (upper side in FIG. 1) may be simply referred to as the "first side" and the "second side", respectively. Also, a direction intersecting the axial direction (for example, a perpendicular direction) is referred to as the "radial direction". In the radial direction, the side closer to 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 comprises a cylinder portion 10 that contains oil as an example of hydraulic fluid, and a rod 20 whose second end protrudes from the cylinder portion 10 and whose first end is slidably inserted into the cylinder portion 10. The shock absorber 2 also comprises a piston portion 30 provided at the first end of the rod 20 and a bottom portion 50 provided at the first end of the cylinder portion 10.

[0012] The cylinder section 10 includes a cylinder 11 for containing oil and an outer cylinder 12 provided on the outside of the cylinder 11. The cylinder section 10 also includes a rod guide section 14 for movably supporting the rod 20, a bump stopper cap 15 attached to the second end of the outer cylinder 12, and an oil seal 16 to prevent oil leakage from the cylinder section 10 and the entry of foreign matter into the cylinder section 10.

[0013] Figure 2 shows an example of the schematic configuration of the piston section 30. Figure 3 shows an example of the piston 31 as viewed axially from the second side. Figure 4 shows an example of the piston 31 as viewed axially from the first side. Figure 5 shows an example of a partial perspective view of the components that make up the piston section 30.

[0014] The piston section 30 moves axially as the rod 20 moves. The piston section 30 comprises a piston 31 having multiple oil passages (described later) that penetrate axially, a compression damping valve group 40 provided on the second side of the piston 31, and a rebound damping valve group 100 provided on the first side of the piston 31. The piston section 30 also comprises an annular member 44, a valve stopper 45, and a nut 46 located on the first side of the rebound damping valve group 100. The piston 31, compression damping valve group 40, rebound damping valve group 100, annular member 44, and valve stopper 45 are fastened to the rod 20 by the nut 46.

[0015] (Piston 31) The piston 31 divides the space inside the cylinder 11 into a first oil chamber Y1, which is the first space in the axial direction, and a second oil chamber Y2, which is the second space in the axial direction. The piston 31 has a through hole 31H on its inside, a compression side oil passage 311 on the outside of the through hole 31H, and an extension side oil passage 312 on the outside of the through hole 31H.

[0016] Furthermore, the piston 31 has a second inner round portion 32 provided on the inside of the second side and a second outer round portion 33 provided on the outside of the second side. In addition, the piston 31 has a second inclined portion 34 provided on the second side and an outer end portion 35 provided on the second side.

[0017] Furthermore, the piston 31 has a first inner round portion 36 provided on the first side, a first outer round portion 37 provided on the first side, and an annular projection portion 38 provided on the first side.

[0018] The through-hole 31H is formed in the axial direction of the piston 31. The first end of the rod 20 is inserted into the through-hole 31H. In this way, the piston 31 is attached to the first end of the rod 20. The pressure-side oil passage 311 is an oil passage that enables oil flow between the first oil chamber Y1 and the second oil chamber Y2 during the compression stroke of the buffer device 2. As shown in Figure 3, the pressure-side oil passage 311 is provided at multiple locations (four locations in this embodiment) at approximately equal intervals in the circumferential direction. The extension oil passage 312 is an oil passage that enables oil flow between the second oil chamber Y2 and the first oil chamber Y1 during the extension stroke of the buffer device 2. As shown in Figure 4, the extension oil passage 312 is provided at multiple locations (four locations in this embodiment) at approximately equal intervals in the circumferential direction.

[0019] The second inner round portion 32 is formed in a substantially annular shape and is provided on the outer circumference of the through hole 31H. The second inner round portion 32 protrudes axially toward the second side from the second end face 31A formed on the second side. In this embodiment, the second inner round portion 32 contacts the inner portion of the compression damping valve group 40.

[0020] The second outer round portion 33 is formed in a substantially annular shape and is located outside the pressure-side oil passage 311. The second outer round portion 33 protrudes axially from the second end face 31A toward the second side. The protruding height of the second outer round portion 33 is slightly higher than that of the second inner round portion 32.

[0021] The second outer round portion 33 is formed along a plane substantially perpendicular to the axial direction of the piston 31. The second outer round portion 33 is the most protruding part on the second side of the piston 31. The second outer round portion 33 forms a portion that contacts the outer part of the compression damping valve group 40.

[0022] The second inclined portion 34 is formed by a surface that is inclined with respect to the axial direction of the piston 31. The second inclined portion 34 is connected to the second outer rounded portion 33 and the outer end portion 35, respectively. The outer end portion 35 is located outside the second inclined portion 34. Furthermore, the outer end portion 35 is formed by a surface that is substantially perpendicular to the axial direction of the piston 31.

[0023] The first inner round portion 36 is formed in a substantially annular shape and is provided on the outer circumference of the through hole 31H. The first inner round portion 36 protrudes axially toward the first side from the first end face 31B formed on the first side. In this embodiment, the first inner round portion 36 contacts the inner portion of the extension damping valve group 100.

[0024] The first outer round portion 37 is formed in a substantially annular shape. The first outer round portion 37 is formed on the first side, outside the extension oil passage 312 and inside the compression oil passage 311. The first outer round portion 37 protrudes axially from the first end face 31B further toward the first side. The protruding height of the first outer round portion 37 is slightly higher than that of the first inner round portion 36. In this embodiment, the first outer round portion 37 protrudes toward the extension damping valve group 100 and functions as a seating surface on which the first valve 110 of the extension damping valve group 100, which will be described later, sits.

[0025] A first inner rounded portion 36 is provided on the inside of the first end face 31B, and a first outer rounded portion 37 is provided on the outside of the first end face 31B. As a result, an annular groove 39 is formed outside the first inner rounded portion 36 and inside the first outer rounded portion 37, recessed to the second side from the first outer rounded portion 37. The groove 39 communicates with the second oil chamber Y2 via the extension oil passage 312. In other words, the extension oil passage 312 functions as a communication passage connecting the groove 39 and the second oil chamber Y2.

[0026] The annular projection 38 is a portion formed in a substantially cylindrical shape. The annular projection 38 is provided on the outer part of the piston 31. The annular projection 38 protrudes more significantly toward the first side in the axial direction than the first outer round portion 37. In other words, the annular projection 38 protrudes axially even further toward the first side than the first outer round portion 37. In this embodiment, the piston 31 is formed, for example, by filling a mold having a predetermined shape with metal powder and sintering the filled metal powder.

[0027] (Compression damping valve group 40) As shown in Figure 2, the compression damping valve group 40 is composed of multiple annular plates made of, for example, metal. The compression damping valve group 40 has a through hole 41H formed on the inside through which the rod 20 passes. The compression damping valve group 40 is also formed to be larger than the outer diameter of the second outer round portion 33. The compression damping valve group 40 covers the second side of the compression oil passage 311 and keeps the second side of the extension oil passage 312 open at all times.

[0028] (Extension damping valve group 100) The rebound damping valve group 100 is constructed by stacking seven metal plates. More specifically, the rebound damping valve group 100 includes a first valve 110 seated on the first outer round portion 37 of the piston 31, a second valve 120 positioned adjacent to the first valve 110, a third valve 130 positioned adjacent to the second valve 120, and a fourth valve 140 positioned adjacent to the third valve 130. The rebound damping valve group 100 also includes a fifth valve 150 positioned adjacent to the fourth valve 140, a sixth valve 160 positioned adjacent to the fifth valve 150, and a seventh valve 170 positioned adjacent to the sixth valve 160. The first valve 110, second valve 120, third valve 130, fourth valve 140, fifth valve 150, sixth valve 160, and seventh valve 170 each have a through hole 105 formed inside for passing the rod 20, and are arranged sequentially around the rod 20 from the piston 31 toward the first side. The diameter of the through hole 105 is smaller than the diameter of the first inner round portion 36, and the inner circumference of the seven valves is fixed between the first inner round portion 36 and the annular member 44.

[0029] The first valve 110 has a circular outer circumference 111. The outer diameter of the first valve 110 is larger than the outer diameter of the first outer round portion 37 of the piston 31, and covers the first side of the groove 39 formed in the piston 31. The first valve 110 has multiple slits 112 formed in the circumferential direction, which are linearly cut out from the outer edge inward. The inner position of the slits 112 is located inside the first outer round portion 37 and outside the first inner round portion 36. Therefore, even when the first valve 110 is seated on the first outer round portion 37, the groove 39 and the first oil chamber Y1 are in communication through the slits 112. Thus, the slits 112 function as orifices that allow oil to flow from the second oil chamber Y2 to the first oil chamber Y1.

[0030] The second valve 120 has a circular outer circumference 121, and its outer diameter is the same as that of the first valve 110. The second valve 120 serves to reinforce the first valve 110 and increase its rigidity. By providing the second valve 120, excessive displacement and deformation of the first valve 110 can be suppressed without increasing the rigidity of the first valve 110 itself. Note that if sufficient rigidity can be ensured by the first valve 110 alone, it is not necessarily required to provide the second valve 120. Hereinafter, the first valve 110 and the second valve 120 may be referred to as the first laminate 101.

[0031] Figure 6 is an example of a view of the third valve 130 in the axial direction. The third valve 130 has a cross-shaped outer circumference 131. In other words, when viewed in the axial direction, the shape of the third valve 130 is a square with its four corners fanned out. That is, the outer circumference 131 of the third valve 130 has a pair of first sides 132 extending in the left-right direction in Figure 6, and a pair of second sides 133 extending in the up-down direction in Figure 6, in other words, in a direction perpendicular to the first sides 132. The distance between the pair of first sides 132 and the distance between the pair of second sides 133 are the same and are the same as the outer diameter of the second valve 120. The third valve 130 also has four arcs 134 connecting the ends of the first sides 132 and the ends of the second sides 133. The size of all four arcs 134 is the same, and when the four arcs 134 are combined, they form a virtual circle. Furthermore, the four arcs 134 are arranged at equal intervals (every 90 degrees) around the through hole 105. In the third valve 130 configured as described above, the portion enclosed by the outer circumference 131 and the through hole 105 contacts the first laminate 101. The portion of the third valve 130 outside the arc 134 becomes a recess 135 that does not contact the first laminate 101. Furthermore, the point on the outer circumference 131 that is furthest from the center of the through hole 105 (for example, the connection point between the first side 132 and the arc 134, and the connection point between the second side 133 and the arc 134) may be the same as the radius of the second valve 120.

[0032] Figure 7 is an example of a view of the fourth valve 140 in the axial direction. The fourth valve 140 has a circular disc 141 with a circular outer circumference 141a and a cylindrical ring 142 provided on the outer circumference 141a of the first side surface of the disc 141. The outer diameter of the disc 141 is the same as the outer diameter of the first valve 110. The outer diameter of the ring 142 is the same as the outer diameter of the disc 141, and the inner diameter of the ring 142 is larger than the inner diameter of the disc 141 (in other words, the diameter of the through hole 105). For example, the inner diameter of the ring 142 can be exemplified as 9 / 10 of the outer diameter of the ring 142. Also, the thickness of the ring 142 (in other words, its axial size) can be exemplified as being between 1 and 1.5 times the thickness of the disc 141.

[0033] The ring 142 is joined to the disc 141 by welding. For example, the welding may be applied spot at multiple locations around the circumference of the ring 142. The method is not limited to welding; the disc 141 and the ring 142 may also be joined by adhesive or welding. As described above, the fourth valve 140 has a ring 142 with a thickness greater than or equal to the thickness of the disc 141 joined to a disc 141, which is an example of a thin circular plate. Therefore, the axial size (in other words, the size in the direction of the centerline) of the outer circumference of the fourth valve 140 is greater than the axial size of the inner circumference.

[0034] Hereinafter, the third valve 130 and the fourth valve 140 may be referred to as the second laminate 102. As described above, the second laminate 102 includes a third valve 130 (an example of a non-circular member) which is positioned adjacent to the first laminate 101 and has a non-circular outer circumference 131, and a fourth valve 140 (an example of a circular member) which is positioned on the opposite side of the piston 31 from the third valve 130 and has a circular outer circumference 141a and is provided with a ring 142.

[0035] The fifth valve 150 has a circular outer circumference 151, and the outer diameter of the fifth valve 150 is the same as the outer diameter of the first valve 110. The sixth valve 160 has a circular outer circumference 161, and its outer diameter is the same as that of the first valve 110. The sixth valve 160 reinforces the fifth valve 150 and increases its rigidity. By providing the sixth valve 160, excessive displacement and deformation of the fifth valve 150 can be suppressed without increasing the rigidity of the fifth valve 150 itself. However, if sufficient rigidity can be ensured by the fifth valve 150 alone, it is not necessarily required to provide the sixth valve 160.

[0036] The seventh valve 170 has a circular outer circumference 171, and its outer diameter is smaller than that of the sixth valve 160. For example, the outer diameter of the seventh valve 170 can be exemplified as 2 / 3 of the outer diameter of the sixth valve 160. The seventh valve 170 reinforces the inner circumference of the fifth valve 150 and the sixth valve 160, thereby increasing the rigidity of the fifth valve 150 and the sixth valve 160. By providing the seventh valve 170, excessive displacement and deformation of the fifth valve 150 and the sixth valve 160 can be suppressed without increasing the rigidity of the fifth valve 150 and the sixth valve 160 themselves. However, if sufficient rigidity can be ensured by the fifth valve 150 and the sixth valve 160, it is not necessarily required to provide the seventh valve 170.

[0037] In the following, the fifth valve 150, the sixth valve 160, and the seventh valve 170 may be referred to as the third laminate 103.

[0038] The annular member 44 described above has an outer diameter smaller than the outer diameter of the seventh valve 170. The valve stopper 45 has an outer diameter smaller than the outer diameter of the seventh valve 170 and larger than the outer diameter of the annular member 44. The thickness of the valve stopper 45 is set to be approximately the same as the thickness of the third laminate 103, for example. The first laminate 101, the second laminate 102, and the third laminate 103 are fixed between the annular member 44 and the valve stopper 45 and the piston 31 by nuts 46. As a result, the inner circumference of the first laminate 101, the second laminate 102, and the third laminate 103 becomes the fixed end side and the outer circumference becomes the free end side, and they flex starting from the outer circumference of the annular member 44. The valve stopper 45 then suppresses excessive deformation of the first laminate 101, the second laminate 102, and the third laminate 103.

[0039] As described above, the extension damping valve group 100 includes a first laminate 101 that seats on the first outer round portion 37, which is an example of the end face of the piston 31; a second laminate 102 positioned on the first side opposite to the piston 31 relative to the first laminate 101; and a third laminate 103 positioned on the first side relative to the second laminate 102. The first laminate 101, the second laminate 102, and the third laminate 103 are attached to the rod 20 by nuts 46 via an annular member 44 and a valve stopper 45. As a result, the inner circumference of the third laminate 103 is pressed by the annular member 44, causing the inner circumference of the first laminate 101 to come into contact with the inner circumference of the second laminate 102, and the inner circumference of the second laminate 102 to come into contact with the inner circumference of the third laminate 103.

[0040] Furthermore, because the fourth valve 140 of the second laminate 102 has a structure in which a ring 142 is joined to the outer circumference 141a of the disc 141, the second side surface of the third laminate 103 is pressed by the ring 142, causing the outer circumference of the third laminate 103 to bend so that it is located on the first side relative to the inner circumference. In other words, the second laminate 102 has a ring 142 (an example of a protrusion) that causes the third laminate 103 to bend so that its outer circumference is located on the opposite side from the piston 31 (in other words, the first side) relative to the inner circumference, even when there is no pressure difference between the two oil chambers, the first oil chamber Y1 and the second oil chamber Y2. As a result, a force acts on the ring 142 to cause the third laminate 103 to return to its original shape, and an initial load acts on the first laminate 101 and the second laminate 102 in the direction toward the piston 31.

[0041] The following describes the effects during the extension process. Figure 8 shows an example of the damping force characteristics of the shock absorber 2. In the extension damping valve group 100 configured as described above, first, when the piston speed is low, oil moves from the second oil chamber Y2 to the first oil chamber Y1 through the slit 112 formed in the first valve 110. Also, a ring 142 is joined to the disc 141 of the fourth valve 140, and an initial load acts on the first laminate 101 and the second laminate 102 in the direction toward the piston 31. As a result, in the region where the piston speed is low, the rate of increase in damping force with respect to increase in piston speed is larger than when the slit 112 is not formed or when no initial load is applied. In other words, the slope of the damping force curve shown in Figure 8 becomes steeper.

[0042] As the piston speed approaches the medium speed range, the hydraulic pressure in the second oil chamber Y2 increases, causing the portion of the first stack 101 located outside the arc 134 of the third valve 130 (in other words, the portion facing the recess 135) to flex starting from the arc 134, and the first stack 101 begins to open. As a result, the damping force curve becomes smooth without generating an inflection point in the region enclosed by the dotted circle in Figure 8. In other words, compared to, for example, the case where the outer circumference of the valve adjacent to the first stack 101 is circular, the first stack 101 begins to open partially, and the hydraulic pressure in the second oil chamber Y2 at the point of opening decreases, so the slope of the damping force curve becomes gentler at an earlier stage as the piston speed approaches the medium speed range.

[0043] As the piston speed increases to a high-speed range, the oil pressure in the second oil chamber Y2 increases, causing the entire extension damping valve group 100 to begin opening. At this time, an annular groove 39 is formed in the piston 31 adjacent to the first valve 110, communicating with the second oil chamber Y2 via the extension oil passage 312. Compared to the case where the groove is not annular, the ratio of the increase in damping force to the increase in piston speed becomes smaller. In other words, the slope of the damping force curve shown in Figure 8 becomes smaller.

[0044] In other words, with the extension damping valve group 100, as shown in the damping force curve in Figure 8, the damping force increases linearly and with a large slope in the low piston speed range, resulting in improved handling stability. On the other hand, in the high piston speed range, the slope becomes smaller, resulting in a better ride comfort. In addition, in the medium piston speed range, the movement becomes smooth without the occurrence of inflection points, which suppresses abrupt changes in the movement of the rod 20 and reduces the generation of abnormal noise inside the vehicle.

[0045] Furthermore, with the extension damping valve group 100, the initial load can be adjusted by adjusting the initial deflection amount of the third laminate 103 by the difference between the thickness of the disc 141 and the thickness of the ring 142 of the fourth valve 140, making it possible to adjust the hydraulic pressure when the entire first laminate 101 begins to open.

[0046] Furthermore, with the extension damping valve group 100, the hydraulic pressure when the first laminate 101 begins to partially open changes depending on the shape of the outer circumference 131 of the third valve 130. Therefore, it is possible to adjust the damping force characteristics by changing the shape of the third valve 130. In addition, it becomes easier to understand the correlation between the shape of the outer circumference 131 of the third valve 130 and the damping force.

[0047] Furthermore, by providing an annular disc with a smaller outer diameter than the first valve 110 between the first laminate 101 and the piston 31, and by changing the number and / or thickness of these discs, it becomes possible to adjust the initial load acting on the first laminate 101.

[0048] The following describes a modified shape of the outer circumference 131 of the third valve 130. (First modified example of the shape of the outer circumference 131 of the third valve 130) Figure 9 shows an example of the third valve 180 according to the first modified example. The third valve 180 according to the first modified example has a different outer circumference 181 shape from that of the third valve 130. When viewed in the axial direction, the shape is a rectangle with four corners cut out in a fan shape. That is, the outer circumference 181 has a pair of first sides 182 extending in the left-right direction in Figure 9, and a pair of second sides 183 extending in the up-down direction in Figure 9, in other words, in a direction perpendicular to the first sides 182. The distance between the pair of second sides 183 is greater than the distance between the pair of first sides 182, the distance between the pair of second sides 183 is the same as the outer diameter of the second valve 120, and the distance between the pair of first sides 182 is smaller than the outer diameter of the second valve 120. The third valve 180 also has four arcs 184 connecting the ends of the first sides 182 and the ends of the second sides 183. All four arcs 184 are the same size.

[0049] In the third valve 180, the portion enclosed by the outer circumference 181 and the through hole 105 contacts the first laminate 101. The portion of the third valve 180 outside the arc 184 becomes a recess 185 that does not contact the first laminate 101.

[0050] With the third valve 180 configured as described above, unlike the third valve 130, the four arcs 184 that serve as the starting points for the first laminate 101 to flex are not uniform, and there are parts that flex more easily than when the first laminate 101 flexes starting from the arc 134. As a result, the flexing characteristics in the damping force curve shown in Figure 8 are further mitigated.

[0051] (Second modified example of the shape of the outer circumference 131 of the third valve 130) Figure 10 shows an example of the third valve 190 according to the second modified example. The third valve 190 according to the second modified example has an outer circumference 191 that is formed by cutting out the left-right ends in Figure 10 from a circle 192 with the same outer diameter as the second valve 120. In other words, the outer circumference 191 has a pair of sides 193 that extend in the vertical direction in Figure 10. In the third valve 190, the portion enclosed by the outer circumference 191 and the through hole 105 contacts the first laminate 101. The portion of the third valve 190 that is outside the pair of sides 193 becomes a recess 194 that does not contact the first laminate 101.

[0052] With the third valve 190 configured as described above, the portion of the first laminate 101 located outside the edge 193 of the third valve 190 according to the second modified example (in other words, the portion facing the recess 194) flexes starting from the edge 193, causing the first laminate 101 to begin opening. As a result, the damping force curve becomes smooth without generating an inflection point in the region enclosed by the dotted circle in Figure 8.

[0053] (Third modified example of the shape of the outer circumference 131 of the third valve 130) Figure 11 shows an example of the third valve 195 according to the third modified example. In the third modified example, the third valve 195 has an elliptical shape in which the outer circumference 196 has the same outer diameter as the outer diameter of the second valve 120. In the third valve 195, the portion enclosed by the outer circumference 196 and the through hole 105 contacts the first laminate 101. The portion of the third valve 195 outside the outer circumference 196 becomes a recess 197 that does not contact the first laminate 101.

[0054] With the third valve 195 configured as described above, the portion of the first laminate 101 located outside the outer circumference 196 of the third valve 195 according to the third modified example (in other words, the portion facing the recess 197) flexes starting from the outer circumference 196, causing the first laminate 101 to begin opening. As a result, the damping force curve becomes smooth without generating an inflection point in the region enclosed by the dotted circle in Figure 8.

[0055] (First modification of valve 140, part 4) Figure 12 shows an example of the fourth valve 145 according to the first modified example, viewed axially from the first side. The fourth valve 145, according to the first modified example, differs from the fourth valve 140 in that it has a circular disc 146 whose center is offset from the center of the circle of the outer circumference 146a, and a ring 142 joined to the outer circumference 146a of the disc 146. Furthermore, the distance from the center of the through hole 105 to the furthest point on the outer circumference 146a is the same as the radius of the second valve 120, and the distance from the center of the through hole 105 to the closest point on the outer circumference 146a is set to be smaller than the radius of the second valve 120.

[0056] According to the fourth valve 145 of the first modified example configured as described above, unlike the fourth valve 140, the initial load acting on the first laminate 101 is not uniform in the circumferential direction, and there are parts of the first laminate 101 that are more prone to deflection than when the initial load is applied by the fourth valve 140. As a result, the bending characteristics in the damping force curve shown in Figure 8 are further mitigated. Furthermore, the fourth valve 145 in the first modification may also be applied when the third valve 180 in the first modification, the third valve 190 in the second modification, or the third valve 195 in the third modification is used instead of the third valve 130.

[0057] (Second variation of the 4th valve 140) Figure 13 shows an example of the fourth valve 147 according to the second modified example, viewed axially from the first side. Figure 14 is a partial cross-sectional view showing an example of the fourth valve 147 according to the second modified example. The fourth valve 147 in the second modification is circular in shape with an outer diameter identical to that of the first valve 110. Furthermore, the fourth valve 147 has a protrusion 148 that extends to the first side formed on its entire outer circumference by press working. In other words, the fourth valve 147 in the second modification differs from the fourth valve 140 in that, instead of having a ring 142 on the first side of the disc 141, a protrusion 148 is formed by press working.

[0058] In the fourth valve 147 configured as described above, the second side surface of the third laminate 103 is pushed by the convex portion 148, causing the outer circumference of the third laminate 103 to bend so that it is positioned on the first side relative to the inner circumference. As a result, a force acts on the convex portion 148 to cause the third laminate 103 to return to its original shape, and an initial load acts on the first laminate 101 in the direction toward the piston 31. Consequently, in the region where the piston speed is low, the ratio of the increase in damping force to the increase in piston speed can be made larger compared to the case where no initial load is acting.

[0059] Furthermore, the fourth valve 147 according to the second modification may also be applied when the third valve 180 according to the first modification, the third valve 190 according to the second modification, or the third valve 195 according to the third modification is used instead of the third valve 130. Also, in the fourth valve 147 according to the second modification, the center of the through hole 105 through which the rod 20 passes may be offset from the center of the outer circumference, as in the fourth valve 145 according to the first modification.

[0060] <Second Embodiment> The extension-side damping valve group 200 according to the second embodiment differs from the extension-side damping valve group 100 according to the first embodiment in that the second laminated body 202, which corresponds to the second laminated body 102, is different. The differences from the first embodiment will be described below. The same reference numerals are used for the same parts in the first and second embodiments, and their detailed descriptions will be omitted.

[0061] Figure 15 shows an example of the schematic configuration of the second laminate 202 of the extension damping valve group 200 according to the second embodiment, as viewed axially from the first side. The second laminate 202 differs from the second laminate 102 according to the first embodiment in that it does not have a third valve 130 and does not protrude to the first side around its entire circumference like the ring 142 of the fourth valve 140.

[0062] More specifically, the second laminate 202 has a circular disc 240 with an outer peripheral portion 241, and a protrusion 242 provided on the outer peripheral portion 241 of the disc 240 that protrudes toward the first side. The disc 240 has the same shape as the disc 141 according to the first embodiment.

[0063] The protrusion 242 has an arc shape and comprises a first protrusion 251 and a second protrusion 252. The first protrusion 251 differs from the ring 142 according to the first embodiment only in its circumferential size. The circumferential size of the first protrusion 251 can be exemplified as, for example, 1 / 6 to 1 / 4 of that of the ring 142. The second protrusion 252 has the same shape as the first protrusion 251, and the first protrusion 251 and the second protrusion 252 are arranged symmetrically with respect to the center of the disc 240.

[0064] The first protrusion 251 and the second protrusion 252 can be exemplified as being joined to the disc 240 by welding, similar to the ring 142. However, the method is not limited to welding; the first protrusion 251 and the second protrusion 252 and the disc 240 may be joined by adhesive or welding.

[0065] As described above, the second laminate 202 has a convex portion 242 with a thickness greater than or equal to the thickness of the disc 240 joined to a disc 240, which is an example of a thin circular plate. Therefore, the axial size (in other words, the direction of the centerline) of the outer circumference of the second laminate 202 where the convex portion 242 is joined is larger than the axial size of the inner circumference. Furthermore, in the second laminate 202, the protrusion 242 contacts the third laminate 103. The portion between the first protrusion 251 and the second protrusion 252 in the circumferential direction becomes a recess 255 that does not contact the third laminate 103.

[0066] In the extension damping valve group 200 configured as described above, the second side surface of the third laminate 103 is pushed by the convex portion 242 of the second laminate 202, causing the outer circumference of the third laminate 103 to bend so that it is positioned on the first side relative to the inner circumference. As a result, a force acts on the convex portion 242 to cause the third laminate 103 to return to its original shape, and an initial load acts on the first laminate 101 in the direction toward the piston 31.

[0067] However, in the circumferential direction of the second laminate 202, the magnitude of the initial load differs between the areas where the protrusions 242 are provided and the areas where the protrusions 242 are not provided (in other words, the areas facing the recesses 255). Therefore, the initial load acting on the first laminate 101 is greater in the areas where the protrusions 242 are provided than in the areas where the protrusions 242 are not provided.

[0068] Therefore, as the piston speed approaches the medium speed range and the hydraulic pressure in the second oil chamber Y2 increases, the portion of the first stack 101 facing the part of the second stack 202 where the protrusion 242 is not provided (in other words, the portion facing the recess 255) begins to open earlier than the portion corresponding to the part where the protrusion 242 is provided. As a result, the damping force curve becomes smooth without generating an inflection point in the region enclosed by the dotted circle in Figure 8. In other words, unlike, for example, the case where the entire circumference of the second stack 202 is provided with protrusions projecting toward the first side, the first stack 101 begins to open partially, and the hydraulic pressure in the second oil chamber Y2 that begins to open decreases, so the slope of the damping force curve becomes gentler at an early stage as the piston speed approaches the medium speed range.

[0069] As a result, with the extension damping valve group 200, similar to the extension damping valve group 100 according to the first embodiment, as shown in the damping force curve in Figure 8, the slope is large and the damping force increases linearly in the low piston speed range, thus improving handling stability. On the other hand, in the high piston speed range, the slope becomes smaller, improving the ride comfort of the vehicle. In addition, in the medium piston speed range, the movement becomes smooth without the occurrence of inflection points, which suppresses abrupt changes in the movement of the rod 20 and suppresses the generation of abnormal noise inside the vehicle.

[0070] Furthermore, the extension damping valve group 200 allows for adjustment of the initial load by adjusting the initial deflection amount of the third laminate 103 using the difference between the thickness of the disc 240 and the thickness of the protrusion 242 of the second laminate 202. This makes it possible to adjust the hydraulic pressure when the entire first laminate 101 begins to open.

[0071] Furthermore, with respect to the extension damping valve group 200, the hydraulic pressure when the first laminate 101 begins to partially open changes depending on the shape of the protrusion 242 of the second laminate 202. Therefore, it is possible to adjust the damping force characteristics by changing the shape of the protrusion 242. In addition, it becomes easier to understand the correlation between the shape of the protrusion 242 and the damping force. A modified example of the protrusion 242 is described below.

[0072] (First modified example of the protrusion 242) Figure 16 shows an example of the protrusion 262 according to the first modified example. The protrusion 262 in the first modified example differs in that it is positioned asymmetrically with respect to the center of the disc 240 with respect to the protrusion 242.

[0073] The protrusion 262 has an arc shape and comprises a first protrusion 271 and a second protrusion 272. The circumferential size of the first protrusion 271 is larger than the circumferential size of the second protrusion 272. The circumferential size of the first protrusion 271 is larger than the circumferential size of the first protrusion 251, for example, it can be exemplified as 1 / 4 to 1 / 3 of the ring 142. The circumferential size of the second protrusion 272 is smaller than the circumferential size of the second protrusion 252, for example, it can be exemplified as 1 / 10 to 1 / 12 of the ring 142. The circumferential central portion of the first protrusion 271 and the circumferential central portion of the second protrusion 272 are arranged symmetrically with respect to the center of the disk 240.

[0074] With the above configuration, the protrusion 262 contacts the third laminate 103, and the portion between the first protrusion 271 and the second protrusion 272 in the circumferential direction becomes a recess 275 that does not contact the third laminate 103. With the protrusion 262 according to the first modified example configured as described above, unlike the protrusion 242, the parts of the first laminate 101 that are prone to bending are not evenly spaced in the circumferential direction, so the bending characteristics in the damping force curve shown in Figure 8 are further mitigated.

[0075] (Second modified example of protrusion 242) Figure 17 shows an example of the protrusion 282 according to the second modified example. The protrusion 282 in the second modified example has a first protrusion 291, a second protrusion 292, and a third protrusion 293, all of which are arc-shaped. The circumferential sizes of the first protrusion 291 and the second protrusion 292 are the same as the circumferential sizes of the first protrusion 271 and the second protrusion 272 in the first modified example, respectively. The circumferential size of the third protrusion 293 is smaller than the circumferential size of the second protrusion 292, and can be exemplified as being, for example, 1 / 12 to 1 / 24 of the ring 142. The circumferential central portions of the first protrusion 291, the second protrusion 292, and the third protrusion 293 are arranged symmetrically with respect to the center of the disc 240.

[0076] With the above configuration, the protrusion 282 contacts the third laminate 103, and the portion between the first protrusion 291 and the second protrusion 292 in the circumferential direction, and the portion between the second protrusion 292 and the third protrusion 293 become recesses 295 that do not contact the third laminate 103. With the convex portion 282 according to the second modified example configured as described above, unlike the convex portion 242, the parts of the first laminate 101 that are prone to bending are no longer equally spaced in the circumferential direction, so the bending characteristics in the damping force curve shown in Figure 8 are further mitigated.

[0077] <Third Embodiment> Figure 18 shows an example of the schematic configuration of the second laminate 302 according to the third embodiment. The second laminate 302 according to the third embodiment differs from the second laminate 202 according to the second embodiment in that the disc 340 corresponding to the disc 240 is different, and that it does not have a protrusion 242 joined to the disc 240. The differences from the second embodiment will be described below. The same reference numerals are used for the same parts in the second and third embodiments, and their detailed descriptions will be omitted.

[0078] The disc 340 according to the third embodiment is circular in shape with an outer diameter identical to that of the first valve 110. The disc 340 has a protrusion 341 that projects toward the first side formed on its outer circumference by press working.

[0079] The protrusion 341 has an arc shape and comprises a first protrusion 351 and a second protrusion 352. The circumferential size and position of the first protrusion 351 and the second protrusion 352 are the same as the size and position of the first protrusion 251 and the second protrusion 252 in the second embodiment. In other words, the second laminate 302 according to the third embodiment differs from the second laminate 202 according to the second embodiment in that the protrusion 242 is joined to the disc 240, whereas the protrusion 341 is formed on the disc 340 by press working.

[0080] As described above, the second laminate 302 according to the third embodiment operates in the same manner as the second laminate 202 according to the second embodiment, and therefore can achieve the same effects as the second laminate 202 described above.

[0081] Furthermore, the protrusion 341 may have two protrusions, the same circumferential size and position as the first protrusion 271 and second protrusion 272 of the protrusion 262 in the first modified example described above. This makes it possible to make the parts of the first laminate 101 that are prone to bending not equally spaced in the circumferential direction, thus further mitigating the bending characteristics in the damping force curve shown in Figure 8.

[0082] Furthermore, the protrusion 341 may have three protrusions, the same circumferential size and position as the first protrusion 291, second protrusion 292, and third protrusion 293 of the protrusion 282 in the second modified example described above. This makes it possible to make the parts of the first laminate 101 that are prone to bending not equally spaced in the circumferential direction, thus further mitigating the bending characteristics in the damping force curve shown in Figure 8.

[0083] <Fourth Embodiment> The extension-side damping valve group 400 according to the fourth embodiment differs from the extension-side damping valve group 100 according to the first embodiment in that the second laminate 402, which corresponds to the second laminate 102, is different. The differences from the first embodiment will be described below. The same reference numerals are used for the same parts in the first and fourth embodiments, and their detailed descriptions will be omitted.

[0084] Figure 19 shows an example of the schematic configuration of the second laminate 402 according to the fourth embodiment, as viewed axially from the second side. The second laminate 402 differs from the second laminate 102 according to the first embodiment in that it does not have a third valve 130 and has a projection 443 that protrudes to the second side from the disc 141 of the fourth valve 140.

[0085] More specifically, the second laminate 402 has a disc 141, a ring 142 (see Figure 7), and a projection 443 that is joined to the second side surface of the disc 141 and protrudes toward the second side. It can be illustrated that the projection 443 has the same shape and size as the convex portion 242 of the second laminate 202 according to the second embodiment, although the direction of protrusion is different. In other words, the projection 443 has a first projection 451 and a second projection 452, which correspond to the first convex portion 251 and the second convex portion 252, and are arranged symmetrically with respect to the center of the disc 141.

[0086] The first projection 451 and the second projection 452 can be exemplified as being joined to the disc 141 by welding, similar to the ring 142. However, the first projection 451 and the second projection 452 and the disc 141 may be joined by adhesive or welding, not limited to welding. In the second laminate 402 described above, the protrusion 443 is in contact with the first laminate 101. The portion between the first protrusion 451 and the second protrusion 452 in the circumferential direction becomes a recess 455 that does not come into contact with the first laminate 101.

[0087] In the extension damping valve group 400 configured as described above, the following occurs: As the piston speed approaches the medium speed range, the hydraulic pressure in the second oil chamber Y2 increases, and the portion of the first stack 101 that is not in contact with the first projection 451 and the second projection 452 of the second stack 402 (in other words, the portion facing the recess 455) flexes earlier than the portion that is in contact with the first projection 451 and the second projection 452, causing the first stack 101 to begin to open. As a result, the damping force curve becomes smooth without generating an inflection point in the region enclosed by the dotted circle in Figure 8. In other words, compared to the case where, for example, all the circular valves adjacent to the first stack 101 are in contact with the first stack 101, the first stack 101 begins to partially open, and the hydraulic pressure in the second oil chamber Y2 at which it begins to open is lower, so the slope of the damping force curve becomes gentler at an earlier stage as the piston speed approaches the medium speed range.

[0088] As a result, with the extension damping valve group 400, similar to the extension damping valve group 100 according to the first embodiment, as shown in the damping force curve in Figure 8, the slope is large and the damping force increases linearly in the low piston speed range, thus improving handling stability. On the other hand, in the high piston speed range, the slope becomes smaller, improving the ride comfort of the vehicle. In addition, in the medium piston speed range, the movement becomes smooth without the occurrence of inflection points, which suppresses abrupt changes in the movement of the rod 20 and suppresses the generation of abnormal noise inside the vehicle.

[0089] Furthermore, the projection 443 may have two projections, the same circumferential size and position as the first and second projections 271 and 272 of the projection 262 in the first modified example described above. This makes it possible to make the parts of the first laminate 101 that are prone to bending not equally spaced in the circumferential direction, thus further mitigating the bending characteristics in the damping force curve shown in Figure 8.

[0090] Furthermore, the projection 443 may have three projections, the same circumferential size and position as the first projection 291, second projection 292, and third projection 293 of the protrusion 282 in the second modified example described above. This makes it possible to make the parts of the first laminate 101 that are prone to bending not equally spaced in the circumferential direction, thus further mitigating the bending characteristics in the damping force curve shown in Figure 8.

[0091] <Fifth Embodiment> The extension-side damping valve group 500 according to the fifth embodiment differs from the extension-side damping valve group 100 according to the first embodiment in that the second laminated body 502, which corresponds to the second laminated body 102, is different. The differences from the first embodiment will be described below. The same reference numerals are used for the same parts in the first and fifth embodiments, and their detailed descriptions will be omitted.

[0092] Figure 20 shows an example of the schematic configuration of the second laminate 502 according to the fifth embodiment, as viewed axially from the first side. The second laminate 502 differs from the second laminate 102 in the first embodiment in that it does not have the disc 141 of the fourth valve 140, and a ring 142 is joined to the first side surface of the third valve 130. More specifically, the second laminate 502 has a third valve 130 and a ring 142. The ring 142 is spot-welded to the outer circumference 131 of the third valve 130 at the portion between a pair of first sides 132 (see Figure 6) and at the portion between a pair of second sides 133 (see Figure 6).

[0093] In the extension damping valve group 500 configured as described above, as the piston speed approaches the medium speed range, the hydraulic pressure in the second oil chamber Y2 increases, causing the portion of the first stack 101 corresponding to the area outside the arc 134 of the third valve 130 to flex starting from the arc 134, and the first stack 101 to begin to open. As a result, the damping force curve becomes smooth without generating an inflection point in the area enclosed by the dotted circle in Figure 8. In other words, compared to, for example, the case where the outer circumference of the valve adjacent to the first stack 101 is circular, the first stack 101 begins to partially open, and the hydraulic pressure in the second oil chamber Y2 at the point of opening decreases, so the slope of the damping force curve becomes gentler at an earlier stage as the piston speed approaches the medium speed range.

[0094] As a result, with the extension damping valve group 500, similar to the extension damping valve group 100 according to the first embodiment, as shown in the damping force curve in Figure 8, the slope is large and the damping force increases linearly in the low piston speed range, thus improving handling stability. On the other hand, in the high piston speed range, the slope becomes smaller, improving the ride comfort of the vehicle. In addition, in the medium piston speed range, the movement becomes smooth without the occurrence of inflection points, which suppresses abrupt changes in the movement of the rod 20 and suppresses the generation of abnormal noise inside the vehicle.

[0095] Furthermore, since the second laminate 502 does not include the disc 141 of the second laminate 102 according to the first embodiment, the number of parts can be reduced, and the rigidity can be reduced, thereby reducing the damping force.

[0096] Furthermore, the second laminate 502 may be a third valve 180 according to the first modification, a third valve 190 according to the second modification, or a third valve 195 according to the third modification, with the ring 142 joined to it, instead of the third valve 130.

[0097] <Sixth Embodiment> The extension-side damping valve group 600 according to the sixth embodiment differs from the extension-side damping valve group 100 according to the first embodiment in that the second laminated body 602, which corresponds to the second laminated body 102, is different. The differences from the first embodiment will be described below. The same reference numerals are used for the same parts in the first and sixth embodiments, and their detailed descriptions will be omitted.

[0098] Figure 21 shows an example of the schematic configuration of the second laminate 602 according to the sixth embodiment, viewed axially from the first side, and an example of the schematic configuration of the third valve 630, viewed axially. The second laminate 602 includes a third valve 630 corresponding to the third valve 130 and a ring 142 for the fourth valve 140. Unlike the second laminate 102 in the first embodiment, the second laminate 602 does not include the disc 141 for the fourth valve 140. In the second laminate 602, the ring 142 is fitted onto the third valve 630.

[0099] The third valve 630 has radial portions 636 that project radially from the center of each of the four arcs 134 relative to the third valve 130 according to the first embodiment. The radial portions 636 can be exemplified as being a rectangle in which the radial direction is the longitudinal direction and the direction perpendicular to the radial direction is the short direction.

[0100] The third valve 630, configured as described above, is bent so that the tips 637 of the four radial portions 636 are located on the first side of the ring 142, with the pair of first sides 132 and the pair of second sides 133 positioned on the second side of the ring 142. The ring 142 is then held in place by the force of the four radial portions 636 returning to their original shape.

[0101] Furthermore, the distance from the center of the through hole 105 to the tip 637 of the radial portion 636 is set such that, with the ring 142 fitted into the third valve 630, the tip 637 is outside the inner circumferential surface of the ring 142 and inside the outer circumferential surface of the ring 142.

[0102] In the extension damping valve group 600 configured as described above, as the piston speed approaches the medium speed range, the oil pressure in the second oil chamber Y2 increases, causing the portion of the first stack 101 corresponding to the area outside the arc 134 of the third valve 630 to flex starting from the arc 134, and the first stack 101 to begin to open. As a result, the damping force curve becomes smooth without generating an inflection point in the area enclosed by the dotted circle in Figure 8. In other words, compared to, for example, the case where the outer circumference of the valve adjacent to the first stack 101 is circular, the first stack 101 begins to partially open, and the oil pressure in the second oil chamber Y2 at which it begins to open decreases, so the slope of the damping force curve becomes gentler at an earlier stage as the piston speed approaches the medium speed range.

[0103] As a result, with the extension damping valve group 600, similar to the extension damping valve group 100 according to the first embodiment, as shown in the damping force curve in Figure 8, the slope is large and the damping force increases linearly in the low piston speed range, thus improving handling stability. On the other hand, in the high piston speed range, the slope becomes smaller, improving the ride comfort of the vehicle. In addition, in the medium piston speed range, the movement becomes smooth without the occurrence of inflection points, which suppresses abrupt changes in the movement of the rod 20 and suppresses the generation of abnormal noise inside the vehicle.

[0104] Furthermore, since the second laminate 602 does not have the disc 141 of the second laminate 102 in the first embodiment, the number of parts can be reduced, and the rigidity can be reduced, thereby reducing the damping force. Also, unlike the second laminate 502 in the fifth embodiment in which the ring 142 is joined to the third valve 130, the ring 142 of the second laminate 602 is not joined to the third valve 630, so it can be manufactured easily.

[0105] Furthermore, the connection between the end of the first side 132 and the end of the second side 133 of the third valve 630 may not be the arc 134, but rather a curvature greater than the curvature of the arc 134. This allows the base end of the radial portion 636 to bend closer to the through hole 105, making the radial portion 636 more flexible.

[0106] (Variation of piston 31) The shape of the piston 31 to which the extension damping valve group 100 to the extension damping valve group 600 according to the first embodiment to the sixth embodiment described above is not particularly limited. For example, the second inner round portion 32 and the second outer round portion 33 of the piston 31, which are in contact with the compression-side damping valve group 40, do not form annular seating surfaces, but rather non-circular, and may form independent seating surfaces for each compression-side oil passage 311.

[0107] Furthermore, the piston 31 may not be glass-shaped with an annular projection 38 on its outer circumference, but rather composed of two pistons divided in the axial direction. Preferably, one of the two pistons has a compression-side oil passage, and the other piston has an extension-side oil passage. This allows the compression-side oil passage and the extension-side oil passage to be the same size, and also allows for the formation of seating surfaces of the same size. Additionally, the compression-side damping valve group 40 may have the same structure as the extension-side damping valve group 100 to the extension-side damping valve group 600 according to the first embodiment. This makes it possible to achieve the same damping force characteristics on the compression side as on the extension side, as shown in Figure 8. Furthermore, by providing an annular disc with a smaller outer diameter than the main valve between the piston, which has a pressure-side oil passage formed therein, and the main valve that seats on this piston, and by changing the number and / or thickness of this disc, it becomes possible to adjust the initial load acting on the main valve. [Explanation of symbols]

[0108] 1...Suspension device, 2...Buffing device, 3...Coil spring, 11...Cylinder, 20...Rod, 30...Piston section, 31...Piston, 37...First outer round section (example of seating surface), 39...Groove, 100, 200, 400, 500, 600...Extension damping valve group, 101...First laminate, 102, 202, 302, 402, 502, 602...Second laminate, 103...Third laminate, 110...First valve (example of valve), 112...Slit, 120...Second Valves, 130, 630... Third valve (example of a non-circular member), 135, 185, 194, 197, 255, 275, 295, 455... Recesses, 140... Fourth valve (example of a circular member), 141... Disc (example of a thin plate), 142... Ring (example of a convex part), 240... Disc (example of a circular member), 242, 262, 282... Convex parts (example of an arc-shaped member), 312... Extension oil passage, 443... Projection (example of an arc-shaped member), Y1... First oil chamber, Y2... Second oil chamber

Claims

1. A piston that divides the oil chamber inside the cylinder containing the hydraulic fluid into a first oil chamber and a second oil chamber, The piston is positioned such that its inner circumference is supported and its outer circumference is a free end, and it is elastically deformable when the pressure in the second oil chamber becomes higher than the pressure in the first oil chamber, and a plurality of laminates are stacked in the direction of the centerline of the cylinder, Equipped with, The piston has a groove that is recessed in an annular shape from the seating surface on the first oil chamber side, and a communication passage that connects the groove and the second oil chamber. The plurality of laminates comprises a first laminate seated on the seating surface of the piston, a second laminate positioned on the opposite side of the piston from the first laminate, and a third laminate positioned on the opposite side of the second laminate. The second laminate has a recess formed on its outer circumference that partially flexes the first laminate when the pressure in the second oil chamber becomes higher than the pressure in the first oil chamber, and a protrusion that flexes the third laminate so that the outer circumference is located on the opposite side from the inner circumference when there is no pressure difference between the first oil chamber and the second oil chamber. The second laminate comprises a non-circular member disposed adjacent to the first laminate and having a non-circular outer periphery, and a circular member disposed on the opposite side from the non-circular member, having a circular outer periphery and being provided with the convex portion. Buffer device.

2. The protrusion of the second laminate protrudes toward the opposite side. The shock absorber according to claim 1.

3. The first laminate has a valve that sits on the seating surface of the piston and has a slit formed on its outer circumference that connects the groove and the first oil chamber. The shock absorber according to claim 1.

4. The circular member has a larger size in the direction of the centerline at the outer circumference than at the inner circumference. The shock absorber according to claim 1.

5. The circular member is formed by joining a thin circular plate to a ring having a thickness greater than or equal to the thickness of the thin plate. The shock absorber according to claim 4.

6. The circular member is formed by press-forming the outer circumference of a thin circular plate, thereby creating the protrusion. The shock absorber according to claim 4.

7. The non-circular member has a rectangular outer periphery when viewed in the direction of the center line, with the four corners cut out in a fan shape. The shock absorber according to claim 1.

8. The non-circular member has a shape in which the outer circumference, when viewed in the direction of the centerline, is cut out so that the ends of the circle are parallel. The shock absorber according to claim 1.

9. The non-circular member has an elliptical shape at its outer circumference when viewed in the direction of the centerline. The shock absorber according to claim 1.

10. The aforementioned circular member has a discrepancy between the center of the circle on its outer circumference and the center of the through hole formed on its inner side. The shock absorber according to claim 1.

11. A piston that divides the oil chamber in a cylinder containing hydraulic fluid into a first oil chamber and a second oil chamber, The piston is positioned such that its inner circumference is supported and its outer circumference is a free end, and it is elastically deformable when the pressure in the second oil chamber becomes higher than the pressure in the first oil chamber, and a plurality of laminates are stacked in the direction of the centerline of the cylinder, Equipped with, The piston has a groove that is recessed in an annular shape from the seating surface on the first oil chamber side, and a communication passage that connects the groove and the second oil chamber. The plurality of laminates comprises a first laminate seated on the seating surface of the piston, a second laminate positioned on the opposite side of the piston from the first laminate, and a third laminate positioned on the opposite side of the second laminate. The second laminate has a recess formed on its outer circumference that partially flexes the first laminate when the pressure in the second oil chamber becomes higher than the pressure in the first oil chamber, and a protrusion that flexes the third laminate so that the outer circumference is located on the opposite side from the inner circumference when there is no pressure difference between the first oil chamber and the second oil chamber. The second laminate comprises a non-circular member disposed adjacent to the first laminate and having a non-circular outer periphery, and a ring joined to the opposite outer periphery of the non-circular member. Buffer device.

12. A piston that divides the oil chamber in a cylinder containing hydraulic fluid into a first oil chamber and a second oil chamber, The piston is positioned such that its inner circumference is supported and its outer circumference is a free end, and it is elastically deformable when the pressure in the second oil chamber becomes higher than the pressure in the first oil chamber, and a plurality of laminates are stacked in the direction of the centerline of the cylinder, Equipped with, The piston has a groove that is recessed in an annular shape from the seating surface on the first oil chamber side, and a communication passage that connects the groove and the second oil chamber. The plurality of laminates comprises a first laminate seated on the seating surface of the piston, a second laminate positioned on the opposite side of the piston from the first laminate, and a third laminate positioned on the opposite side of the second laminate. The second laminate has a recess formed on its outer circumference that partially flexes the first laminate when the pressure in the second oil chamber becomes higher than the pressure in the first oil chamber, and a protrusion that flexes the third laminate so that the outer circumference is located on the opposite side from the inner circumference when there is no pressure difference between the first oil chamber and the second oil chamber. The second laminate has a circular member with a circular outer periphery and a plurality of arc-shaped members joined to the outer periphery of the circular member. Buffer device.

13. A piston that divides the oil chamber in a cylinder containing hydraulic fluid into a first oil chamber and a second oil chamber, The piston is positioned such that its inner circumference is supported and its outer circumference is a free end, and it is elastically deformable when the pressure in the second oil chamber becomes higher than the pressure in the first oil chamber, and a plurality of laminates are stacked in the direction of the centerline of the cylinder, Equipped with, The piston has a groove that is recessed in an annular shape from the seating surface on the first oil chamber side, and a communication passage that connects the groove and the second oil chamber. The plurality of laminates comprises a first laminate seated on the seating surface of the piston, a second laminate positioned on the opposite side of the piston from the first laminate, and a third laminate positioned on the opposite side of the second laminate. The second laminate has a recess formed on its outer circumference that partially flexes the first laminate when the pressure in the second oil chamber becomes higher than the pressure in the first oil chamber, and a protrusion that flexes the third laminate so that the outer circumference is located on the opposite side from the inner circumference when there is no pressure difference between the first oil chamber and the second oil chamber. The second laminate comprises a circular member having a circular outer circumference, a plurality of arc-shaped members joined to the piston-side surface of the circular member, and a ring joined to the opposite side of the circular member. Buffer device.

14. A buffer device according to any one of claims 1 to 13, A coil spring arranged around the aforementioned shock absorber, A suspension system equipped with [a specific feature].

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