shock absorber

Abstract

The present application provides a technology capable of improving the characteristics of the rise of the damping force of a vane valve of a shock absorber. In the shock absorber, a piston is reciprocally fitted to the inner wall of a cylinder. The piston has a damping force generating valve that generates a damping force corresponding to the speed of the piston. A ring-shaped vane valve allows flexing to both sides of the axial direction of the piston with one of the outer periphery and the inner periphery as a free end. Ring-shaped opposing portions are provided with a gap between the free end of the vane valve. The vane valve has a first vane, a second vane stacked on one side in the axial direction of the first vane, and a third vane stacked on the other side in the axial direction of the first vane. The second vane and the third vane each have a notch portion at the free end.

Description

Technical Field

[0001] This invention relates to a shock absorber. Background Technology

[0002] Patent Document 1 discloses a shock absorber with a non-seated vane valve having a stacked structure. In this vane valve, at least one set of two adjacent vanes are axially spaced apart by a gap forming member that is either separate from or integrally formed with one of the two adjacent vanes.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-076920 Summary of the Invention

[0004] Typically, in vane valves, the vane valve remains closed until its end face is raised relative to the opposing portion by the thickness of the vane valve. However, if it opens, the fluid flow rate changes drastically, causing the increase in damping force in the low-speed region to become discontinuous. As a result, high-frequency vibrations may be generated on the vehicle's springs, leading to a deterioration in ride comfort.

[0005] The purpose of this invention is to provide a technique for improving the characteristics of damping force rise in the vane valve of a shock absorber.

[0006] To address the aforementioned issues, a shock absorber according to one embodiment of the present invention comprises: a cylinder; and a piston reciprocally fitted into the inner wall of the cylinder. The piston has a damping force generating valve that generates a damping force corresponding to the piston's velocity. The damping force generating valve comprises: an annular vane valve, allowing flexure to both sides of the piston's axial direction with one of its outer and inner circumferences as free ends; and an annular opposing portion, spaced apart from the free ends of the vane valve. The vane valve comprises: a first vane; a second vane stacked on one axial side of the first vane; and a third vane stacked on the other axial side of the first vane. The second and third vanes each have a notch at their free ends.

[0007] Invention Effects

[0008] According to the present invention, a technique is provided that can improve the characteristics of damping force rise in the vane valve of a shock absorber. Attached Figure Description

[0009] Figure 1 This is a cross-sectional view of the shock absorber in the embodiment.

[0010] Figure 2 (a) is an enlarged representation. Figure 1 A cross-sectional view of a portion of the valve that generates damping force at low speeds. Figure 2 (b) is a top view of the vane valve.

[0011] Figure 3 (a) ~ Figure 3 (d) is used to explain Figure 2 The diagram shows how the damping force causes the valve to move.

[0012] Figure 4 (a) ~ Figure 4 (c) is a diagram used to illustrate the operation of the damping force generating valve in the comparative example.

[0013] Figure 5 This is a diagram showing the characteristics of the damping force generating valve in the implementation method and comparative example.

[0014] Figure 6 of (a) Figure 6 (b) is a cross-sectional view of a portion of the damping force generating valve in the modified example. Figure 6 (c) Figure 6 (d) is a top view of the second blade of the modified example.

[0015] Figure 7 of (a) Figure 7 (b) is a cross-sectional view of a portion of the damping force generating valve in the modified example. Detailed Implementation

[0016] Hereinafter, identical or equivalent components and parts shown in the figures will be labeled with the same symbols, and appropriate repetitions of explanation will be omitted. Furthermore, for ease of understanding, the dimensions of the parts in each figure will be shown at appropriate scales. Also, in each figure, parts of components that are not important in explaining the embodiments will be omitted.

[0017] Figure 1 This is a cross-sectional view of the shock absorber 10 according to the embodiment. Specifically, Figure 1 This is a cross-sectional view showing the overall structure of the piston 18 disposed within the cylinder block 12 of the shock absorber 10. As an example, the shock absorber 10 is mounted on a vehicle.

[0018] The shock absorber 10 includes: a cylinder 12 extending along an axis 11; and a piston 18 reciprocatingly fitted into the inner wall of the cylinder 12 along the axis 11, forming an upper cylinder chamber 14 and a lower cylinder chamber 16 within the cylinder 12. The upper cylinder chamber 14 and the lower cylinder chamber 16 are filled with oil 19 as a working fluid. The piston 18 has a rod portion 18R extending along the axis 11 and a piston body 18M mounted on the lower end of the rod portion 18R.

[0019] Although not shown, the upper and lower ends of the cylinder block 12 are closed by end caps, and the rod portion 18R extends through the upper end cap to the outside of the cylinder block 12. The upper end of the rod portion 18R is connected to the vehicle body, and the lower end of the cylinder block 12 is connected to the lower spring component of the vehicle. Furthermore, a free piston is disposed between the piston body 18M and the lower end cap inside the cylinder block 12. The free piston and the lower end cap together form an air chamber, separating the air chamber from the lower chamber 16 of the cylinder block. As the shock absorber 10 extends and retracts, the volume of the rod portion 18R within the cylinder block 12 changes, and the air chamber absorbs this volume change.

[0020] The piston body 18M has a damping force generating valve 20 for extended stroke, a damping force generating valve 22 for shortened stroke, and a damping force generating valve 24 for low-speed operation. These damping force generating valves 20, 22, and 24 are configured to generate a damping force corresponding to the piston speed of the piston 18. The low-speed damping force generating valve 24 generates a suitable damping force when the piston speed is in the low-speed region. The low-speed region refers to the extremely low speed region where the piston speed is very low, such as during the starting of the piston 18, and the piston speed is close to zero. The piston body 18M includes a main body 18MM and a secondary body 18MS. These damping force generating valves 20, 22, and 24, the main body 18MM, and the secondary body 18MS are mounted to the lower end of the rod 18R by means of nuts 28 that engage with external threads 26 provided at the lower end of the rod 18R, clamped between support rings 30.

[0021] A resin sealing component 32 is installed on the outer periphery of the main body 18mm, and the sealing component 32 slides freely in contact with the inner wall of the cylinder 12. The sub-body 18MS has an outer diameter smaller than the inner wall of the cylinder 12, and is fixed to the lower end of the main body 18mm by pressing, forming an intermediate chamber 34 together with the main body 18mm. An extension stroke passage 36 and a shortening stroke passage 38 are formed in the main body 18mm, and multiple passages 40 shared by the extension stroke and shortening stroke are formed in the sub-body 18MS.

[0022] The passage 36 is always connected to the arcuate groove 42 and the annular groove 44 formed on the upper and lower surfaces of the main body 18 mm apart, respectively, and the arcuate groove 42 and the annular groove 44 extend along the axis 11. The arcuate groove 42 is always connected to the upper chamber 14 of the cylinder block via the notch 46 formed on the radially outer boss portion, regardless of whether the damping force generating valve 22 is in the closed valve state. The annular groove 44 is always connected to the intermediate chamber 34 via the notch 45 formed on the radially outer boss portion, even when the damping force generating valve 20 is in the closed valve state.

[0023] The passage 38 is always connected at its upper end to the arcuate groove 48 formed on the upper surface of the main body 18 mm and extending along the axis 11, and at its lower end to the intermediate chamber 34. Even when the damping force generating valve 22 is in the closed state, the arcuate groove 48 is always connected to the upper chamber 14 of the cylinder block via a notch 49 formed on its radially outer boss portion. The passage 40 is always connected at its upper end to the intermediate chamber 34, and at its lower end to the annular groove 41. As described in detail later, the annular groove 41 is always connected to the lower chamber 16 of the cylinder block via the low-speed damping force generating valve 24. In addition, in Figure 1 The diagram shows one passage 36 and one passage 38, but multiple passages can also be set up with each other spaced apart around axis 11.

[0024] The extension stroke damping force generating valve 20 is formed of a stack of multiple elastically deformable annular plate-shaped blades 21 and is disposed within the intermediate chamber 34. The damping force generating valve 20 is cantilevered, with its inner edge in the radial direction of the piston 18 sandwiched between the main body 18mm and the secondary body 18ms along with the spacer 43. The shortening stroke damping force generating valve 22 is also formed of a stack of multiple elastically deformable annular plate-shaped blades 23 and is disposed within the upper chamber 14 of the cylinder block. The damping force generating valve 22 is cantilevered, with its inner edge in the radial direction of the piston 18 sandwiched between the support ring 30 and the main body 18mm along with the spacer 47. Various known structures can be used for the piston 18 and the damping force generating valves 20 and 22.

[0025] The low-speed damping force generating valve 24 is a non-seated damping force generating valve with a double-opening structure, comprising a valve section 50 and an opposing section 52.

[0026] The valve section 50 is constructed by stacking an annular plate-shaped vane valve 54 and two annular plate-shaped auxiliary vane valves 56, 56 along the axial direction of the piston 18. One auxiliary vane valve 56 is stacked on one side of the vane valve 54 along its axial direction. The other auxiliary vane valve 56 is stacked on the other side of the vane valve 54 along its axial direction. The outer diameter of the vane valve 54 is larger than the outer diameter of each of the auxiliary vane valves 56, 56. The valve section 50 is configured to elastically deform due to the pressure difference between the upper chamber 14 and the lower chamber 16 of the cylinder. Various known structures can be used for the auxiliary vane valves 56, 56.

[0027] Figure 2 (a) is an enlarged representation. Figure 1 A cross-sectional view of a portion of valve 24, which generates low-speed damping force. Figure 2 (b) is a top view of the vane valve 54. Figure 2 The cross section of the vane valve 54 in (a) is along Figure 2 (b) The cross section of line A-A'.

[0028] The vane valve 54 has a first vane 2a in the shape of an annular plate, a second vane 2b in the shape of a generally annular plate stacked on one side of the axial direction of the first vane 2a, and a third vane 2c in the shape of a generally annular plate stacked on the other side of the axial direction of the first vane 2a. The outer diameters of the first vane 2a, the second vane 2b, and the third vane 2c are all equal. The first vane 2a, the second vane 2b, and the third vane 2c are elastic.

[0029] like Figure 2 As shown in (b), the second blade 2b is shaped based on a circular plate and has four notches 4b on its radially outer edge, i.e., the free end 55. The notches 4b are formed in a predetermined shape, such as a generally quadrilateral shape, at predetermined intervals, for example, 90°, in the circumferential direction of the piston 18. The width of the notches 4b is set to w.

[0030] The third blade 2c has the same shape as the second blade 2b, and has four notches 4c on the outer edge in the radial direction, i.e., the free end 55.

[0031] Viewed axially, the notch 4b of the second blade 2b overlaps with the notch 4c of the third blade 2c. The radial length of the notch 4b is equal to the radial length of the notch 4c. The width of the notch 4b is equal to the width of the notch 4c. Alternatively, the radial length of the notch 4b can differ from the radial length of the notch 4c. The width of the notch 4b can also differ from the width of the notch 4c. By making the dimensions of the notch 4b and the notch 4c different, the damping force characteristics can be set independently during the shortening stroke and the extension stroke.

[0032] like Figure 1 As shown, the first blade 2a, second blade 2b, third blade 2c of the vane valve 54, and the auxiliary vane valves 56, 56 are cantilevered by the piston 18 at their inner edges in the radial direction. These first blades 2a, etc., are cantilevered at their inner edges in a manner that, together with a plurality of spacers 58, are sandwiched between the auxiliary body 18MS and the nut 28. Being further outward than the spacers 58 in the valve section 50, they allow for axial deflection to the upper and lower sides of the piston 18. Thus, in this embodiment, the inner periphery of the vane valve 54 is a fixed end, and the outer periphery is a free end 55.

[0033] As will be described later, during the extension stroke of the shock absorber 10, the vane valve 54 moves towards the lower end of the cylinder 12. Figure 1 , Figure 2 The lower side of (a) flexes. Conversely, during the shortening stroke of the shock absorber 10, the vane valve 54 deflects towards the upper end of the cylinder 12. Figure 1 , Figure 2 The upper side of (a) is flexed.

[0034] like Figure 1As shown, the secondary body 18MS of the piston 18 has a cylindrical portion that protrudes downward and an annular opposing portion 52 that protrudes radially inward from the lower end of the cylindrical portion.

[0035] like Figure 1 , Figure 2 As shown in (a), the opposing portion 52 is configured to face the free end 55 of the vane valve 54 radially outward, and a gap G1 is formed between it and the free end 55. That is, the opposing portion 52 protrudes toward the free end 55 of the outer peripheral surface of the vane valve 54 in its unflexed state, and its inner peripheral surface becomes the opposing surface facing the outer peripheral surface of the vane valve 54. In addition, "unflexed state" refers to the state under no load. The gap G1 functions as a throttling orifice. The annular groove 41 is always in communication with the lower chamber 16 of the cylinder block via this gap G1.

[0036] As explained above, notch 46, arc groove 42, passage 36, annular groove 44, notch 45, intermediate chamber 34, passage 40, and annular groove 41 correspond to the extension stroke connecting the upper cylinder chamber 14 and the lower cylinder chamber 16. Annular groove 41, passage 40, intermediate chamber 34, passage 38, arc groove 48, and notch 49 correspond to the shortening stroke connecting the upper cylinder chamber 14 and the lower cylinder chamber 16. Gap G1 is part of both the extension stroke and shortening stroke connecting paths.

[0037] Next, the operation of the shock absorber 10 based on the above structure will be explained. During the extension stroke of the shock absorber 10, the pressure in the upper cylinder chamber 14 is higher than the pressure in the lower cylinder chamber 16. Therefore, the oil 19 in the upper cylinder chamber 14 intends to flow to the lower cylinder chamber 16 via the aforementioned connection path during the extension stroke. As a result, the vane valve 54 of the valve 24 elastically deforms due to the damping force at a low speed, and flows towards... Figure 1 , Figure 2 The lower side of (a) is flexed.

[0038] In contrast, during the shortened stroke of the shock absorber 10, the pressure in the lower cylinder chamber 16 is higher than the pressure in the upper cylinder chamber 14. Therefore, the oil 19 in the lower cylinder chamber 16 intends to flow to the upper cylinder chamber 14 via the aforementioned connection path during the shortened stroke. As a result, the vane valve 54 elastically deforms and flows towards... Figure 1 , Figure 2 The upper side of (a) is flexed.

[0039] If the piston speed increases during the extension and retraction of the shock absorber 10, the pressure difference between the upper chamber 14 and the lower chamber 16 of the cylinder increases. The low-speed damping force generating valve 24 is configured to open at a piston speed lower than the piston speed when the damping force generating valves 20 and 22 are open, i.e., at a pressure difference smaller than the pressure difference when the damping force generating valves 20 and 22 are open. This structure can be achieved by adjusting parameters affecting valve rigidity, such as the material and thickness of the valve.

[0040] Figure 3 (a) ~ Figure 3 (d) is used to explain Figure 2 The diagram shows the operation of the damping force generating valve 24. The following explanation describes the operation of the shock absorber 10 during the shortening stroke, but the same applies to the extending stroke. In the low-speed damping force generating valve 24, the elastic deformation of the vane valve 54 increases with the higher the piston speed, i.e., the greater the pressure difference.

[0041] Figure 3 (a) indicates the state when the shock absorber 10 begins to shorten. The piston speed of the shock absorber 10 is zero. The vane valve 54 is not deflected. When the shock absorber 10 begins to shorten, the upper side of the vane valve 54 becomes low pressure and the lower side becomes high pressure.

[0042] The range within which the upper end of the free end 55 of the first blade 2a is at or above the lower surface of the opposing portion 52, and the lower end of the free end 55 of the first blade 2a is at or below the upper surface of the opposing portion 52, is defined as the range of elastic deformation. When the elastic deformation of the blade valve 54 is within the defined range, the shortest distance between the free end 55 of the first blade 2a and the inner circumferential surface of the opposing portion 52 is substantially independent of the elastic deformation and remains constant. Therefore, when the elastic deformation of the blade valve 54 is within the defined range, the opening area of ​​the throttling orifice and the effective passage cross-sectional area are substantially independent of the elastic deformation of the blade valve 54 and remain constant.

[0043] The upper limit of the piston speed within the elastic deformation range of the vane valve 54 during the shortening stroke of the shock absorber 10 is set as a predetermined speed. This predetermined speed is a slightly low speed where the piston speed is close to zero. In the low-speed region where the piston speed is below the predetermined speed, the elastic deformation of the vane valve 54 is within the predetermined range, and the damping force generating valve 22 for shortening the stroke is closed. That is, in this low-speed region, the slightly low-speed damping force generating valve 24 generates a damping force corresponding to the piston speed, and thus the damping force is adjusted by the operation of the damping force generating valve 24. Moreover, in this low-speed region, the oil 19 passes through a throttling orifice with a very small opening area, so the damping force increases sharply with the increase of the piston speed.

[0044] Figure 3 (b) indicates the piston speed ratio of the shock absorber 10. Figure 3(a) is a high state. The piston speed is greater than the specified speed. Before the vane valve 54 raises its thickness, the notch 4c becomes a flow path and the flow rate of oil 19 increases. Arrow P1 indicates the path of oil 19 through the notch 4c. That is, if the elastic deformation of the vane valve 54 exceeds the specified range, and the lower end of the free end 55 of the first vane 2a is higher than the upper surface of the opposing part 52, then the notch 4c becomes a flow path. If the axial distance between the lower end of the free end 55 of the first vane 2a and the upper surface of the opposing part 52 is set as x, and the number of notches 4c is set as n, then the opening area is approximately "nwx".

[0045] Thus, the free end 55 of the vane valve 54 has the following shape: if the free end 55 is subjected to pressure and deflects in the axial direction beyond a specified range, the opening area between the free end 55 and the opposing part 52 is increased compared with the free end 55 when it is not deflected.

[0046] Figure 3 (c) indicates the piston speed ratio of shock absorber 10. Figure 3 (b) is a high state. If the vane valve 54 raises its thickness, the flow rate will increase further.

[0047] Figure 3 (d) indicates the piston speed ratio of shock absorber 10. Figure 3 The state of (c) is a high state. Since the opening area increases with the amount of lifting, the flow rate also increases accordingly.

[0048] In the speed region where the piston speed is higher than the specified speed and the damping force generating valve 22 for shortening the stroke is still closed, the flow rate of oil 19 through the damping force generating valve 24 increases with the increase of piston speed. As a result, the damping force increases with the increase of piston speed at a lower rate than in the aforementioned low-speed region.

[0049] Figure 4 (a) ~ Figure 4 (c) is a diagram illustrating the operation of the damping force generating valve 24X in the comparative example. In the comparative example, unlike the embodiment, the vane valve 54X consists of a single vane and does not have a notch. That is, in the embodiment, after replacing the single vane of the comparative example with multiple thin-walled vanes, notches are provided on the vanes on both sides of the axial direction.

[0050] Figure 4 (a) indicates the state when the shock absorber begins to shorten. The piston speed of shock absorber 10 is zero. The vane valve 54X is not deflected.

[0051] Figure 4 (b) indicates the piston speed ratio of the shock absorber. Figure 4(a) is the high state. The lower end of the free end 55X of the vane valve 54X is at the same height as the upper surface of the opposing part 52. Before the vane valve 54X raises its thickness, the opening area between the free end 55X of the vane valve 54X and the opposing part 52 remains substantially unchanged. Oil 19 passes through the throttling orifice. Therefore, from Figure 4 The state of (a) to Figure 4 Up to state (b), the damping force increases sharply with the increase of piston speed.

[0052] Figure 4 (c) indicates the piston speed ratio of the shock absorber. Figure 4 (b) is the higher state. The vane valve 54X is raised more than its thickness. At this time, if the axial distance between the lower end of the free end 55X and the upper surface of the opposing part 52 is set as x, and the outer diameter of the vane valve 54X is set as r, then the opening area is approximately "2πrx". Since the opening area increases with the amount of raising, the flow rate also increases with it.

[0053] Figure 5 The characteristics of the damping force generating valve 24 of the embodiment and the damping force generating valve 24X of the comparative example are shown in a general way. Figure 5 The horizontal axis of the graph represents the flow rate Q of oil 19 through the damping force generating valve 24, and the vertical axis represents the pressure difference ΔP. The flow rate Q corresponds to the piston speed. The pressure difference ΔP corresponds to the damping force. The characteristics of the damping force generating valve 24 of the embodiment are represented by solid lines, and the characteristics of the damping force generating valve 24X of the comparative example are represented by dashed lines.

[0054] In the implementation, Figure 3 The state of (a) is equivalent to Figure 5 The characteristic of point C1. Figure 3 The state of (b) is equivalent to Figure 5 The flow rate Q is slightly larger than point C2 in the characteristic. The specified speed is equivalent to the piston speed at point C2. Figure 3 The state of (c) is equivalent to Figure 5 The characteristic is near point C3. Figure 3 The state of (d) is equivalent to Figure 5 The characteristic is near point C4.

[0055] In the comparative example, Figure 4 The state of (a) is equivalent to Figure 5 The characteristic of point C1. Figure 4 The state of (b) is equivalent to Figure 5 The characteristic is near point C2X. Figure 4 The state of (c) is equivalent to Figure 5 The characteristic is near point C4.

[0056] In the comparative example, as described above, in Figure 5Within the flow rate Q from point C1 to point C2X, the damping force increases sharply with increasing piston speed because the orifice opening area is constant. Beyond point C2X, the increase in damping force relative to piston speed decreases significantly because the orifice area increases with lifting. Thus, with point C2X as the boundary, the slope of the characteristic curve changes drastically, and the increase in damping force becomes discontinuous. As a result, high-frequency vibrations may be generated in the vehicle's springs, potentially leading to a deterioration in ride comfort.

[0057] On the other hand, in the vane valve 54 with notches 4b and 4c in the embodiment, after the vane valve 54 is raised beyond a predetermined range, it has an opening area of ​​"nwx" before the vane valve 54 raises its thickness. That is, in the embodiment, in Figure 5 Within the flow rate Q from point C2 to point C3, the opening area is larger than that of the comparative example. Therefore, the damping force changes before the blade valve 54 lifts its thickness, thus improving the discontinuity and making the rise of the damping force relatively smooth.

[0058] Thus, according to the embodiment, the notches 4b and 4c on the second blade 2b and the third blade 2c on both axial sides of the vane valve 54 gradually increase in opening area as the flow rate increases. Therefore, the damping force in the low-speed region can rise relatively smoothly relative to the increase in piston speed. That is, the characteristics of the damping force increase can be improved. Therefore, high-frequency vibrations generated on the vehicle's springs can be suppressed, and the vehicle's ride comfort can be improved.

[0059] Furthermore, by using a single-blade valve 54X, which is composed of multiple blades and has thinner walls for each blade, tensile stress can be reduced, thereby improving durability while maintaining rigidity.

[0060] Furthermore, by adjusting the size and number of notches 4b and 4c in the second blade 2b and the third blade 2c, the damping force characteristics on both the elongation side and the compression side can be changed respectively, thus improving the adjustability of the damping force.

[0061] Next, other structural examples of the damping force generating valve 24 will be described. Hereinafter, in conjunction with... Figure 2 The explanation will focus on the structural differences of the damping force generating valve 24 in (a).

[0062] Figure 6(a) is a cross-sectional view of a portion of the damping force generating valve 24 of the first variation of the embodiment. The vane valve 54 is composed of five vanes stacked together. The vane valve 54 also has a generally annular plate-shaped fourth vane 2d stacked on one side of the axial direction of the second vane 2b and a generally annular plate-shaped fifth vane 2e stacked on the other side of the axial direction of the third vane 2c. The outer diameters of the first vane 2a, the second vane 2b, the third vane 2c, the fourth vane 2d, and the fifth vane 2e are all equal.

[0063] The fourth blade 2d has a shape based on a circular annular plate and has multiple notches 4d at its free end 55. The fifth blade 2e has a shape based on a circular annular plate and has multiple notches 4e at its free end 55. When viewed axially, the notches 4d of the fourth blade 2d are positioned to overlap with the notches 4b of the second blade 2b. When viewed axially, the notches 4e of the fifth blade 2e are positioned to overlap with the notches 4c of the third blade 2c.

[0064] Thus, in the first modification, by stacking multiple blades to form the blade valve 54, and by providing notches on each blade, the number of stages that reduce the sharp rise in damping force corresponding to the number of stacked blades can be increased. Therefore, the degree of freedom in adjusting the damping force characteristics can be improved.

[0065] The width of the notch 4d of the fourth blade 2d is greater than the width of the notch 4b of the second blade 2b. The width of the notch 4e of the fifth blade 2e is greater than the width of the notch 4c of the third blade 2c. Thus, it is preferable that the notch width is larger the further outward the blade is in the axial direction. This is because when the width of the notch 4d of the fourth blade 2d on the outer side in the axial direction is smaller than the width of the notch 4b of the second blade 2b on the inner side in the axial direction, and when the width of the notch 4e of the fifth blade 2e is smaller than the width of the notch 4c of the third blade 2c, the flow path is restricted when the blade valve 54 flexes.

[0066] Furthermore, the radial length of the notch 4c of the third blade 2c is longer than the radial length of the notch 4b of the second blade 2b. The radial length of the notch 4e of the fifth blade 2e is longer than the radial length of the notch 4d of the fourth blade 2d. Therefore, the damping force characteristics can be set independently during the shortening and extending strokes.

[0067] Figure 6 (b) is a cross-sectional view of a portion of the damping force generating valve 24 of the second modified example. The vane valve 54 also has a fourth vane 2d in the shape of an annular plate stacked on one side of the axial direction of the second vane 2b and a fifth vane 2e in the shape of an annular plate stacked on the other side of the axial direction of the third vane 2c.

[0068] The outer diameters of blades 2a, 2b, and 2c are all equal. The outer diameters of blades 2d and 2e are different and smaller than the outer diameter of blade 2a. Blades 2d and 2e do not have notches. When viewed axially, blade 2d does not overlap with the notch 4b of blade 2b. When viewed axially, blade 2e does not overlap with the notch 4c of blade 2c.

[0069] In this way, the damping force characteristics can be adjusted by making the outer diameters of multiple blades different. This also increases the degree of freedom in adjusting the damping force characteristics.

[0070] Figure 6 (c) is a top view of the second blade 2b in the third variation. Figure 6 As shown in (c), the number of notches 4b can be set to be greater than that of other notches. Figure 2 The structure of (b) is complex, and the radial length of the notch 4b can also be set to be greater than that of the other two. Figure 2 The structure of (b) is long.

[0071] Figure 6 (d) is a top view of the second blade 2b in the fourth variation. For example... Figure 6 As shown in (d), the number of notches 4b can be set to be greater than that of other notches. Figure 2 The structure of (b) is less complex, and the radial length of the notch 4b can also be set to be greater than that of the other two. Figure 2 The structure of (b) is long.

[0072] The number, radial length, and width of the notches 4b and 4c can be appropriately determined through experimentation or simulation to obtain the desired damping force characteristics. The same applies to the notches 4d and 4e. Thus, by changing the number and shape of the notches 4b, 4c, 4d, and 4e, the damping force characteristics can be adjusted.

[0073] Figure 7 (a) is a cross-sectional view of a portion of the damping force generating valve 24 in the fifth variation of the embodiment. The vane valve 54 has a plurality of inclined surfaces at its free end 55. The plurality of inclined surfaces are formed at predetermined intervals in the circumferential direction of the piston 18. The inclined surfaces are inclined radially inward and axially downward. In this example, it has the effect of suppressing a sharp rise in damping force during a shortened stroke. Thus, by deforming the shape of a portion of the free end 55 of the vane valve 54, the rise in damping force can be suppressed in the same way as in the embodiment.

[0074] Alternatively, the inclined surface can also be inclined radially inward and upward. In this case, it has the effect of suppressing a sharp increase in damping force during the extension stroke. The free end 55 of the vane valve 54 can have both of these inclined surfaces simultaneously. Furthermore, the free end 55 as a whole can also be an inclined surface.

[0075] Figure 7 (b) is a cross-sectional view of a portion of the damping force generating valve 24 in the sixth variation of the embodiment. The opposing portion 52 has multiple inclined surfaces on its end face. The multiple inclined surfaces are formed at predetermined intervals in the circumferential direction of the piston 18. That is, the opposing portion 52 is provided with the same shape as the free end 55 of the vane valve 54 in the fifth variation. The inclined surfaces are inclined radially outward and axially downward. In the illustrated example, it has the effect of suppressing a sharp rise in damping force during the extension stroke. The same effect as in the embodiment can also be obtained in the structure of the sixth variation.

[0076] Alternatively, the inclined surface can also be inclined radially outward and upward. In this case, it has the effect of suppressing the sharp rise of damping force during shortened stroke. The end face of the opposing portion 52 can have both of these inclined surfaces simultaneously. Furthermore, the entire end face of the opposing portion 52 can also be an inclined surface.

[0077] Although not shown in the figure, the shape of the free end 55 of the blade valve 54 in the embodiments, the first and the second variations can also be provided in the opposing part 52.

[0078] The present invention has been described above according to embodiments. The embodiments are merely illustrative, and various modifications and variations in the combination of the constituent elements or processing flows are also within the scope of the present invention, as will be understood by those skilled in the art.

[0079] For example, the damping force generating valve 24 of the embodiment has a structure in which the inner edges of multiple blades in the radial direction of the piston 18 are cantilevered by the piston 18. Not limited to this structure, the damping force generating valve 24 may also have a structure in which the outer edges of multiple blades in the radial direction of the piston 18 are cantilevered by the piston. That is, the blade valve 54 only needs to allow deflection to both sides of the piston 18 axially, with one of its outer and inner circumferences as a free end.

[0080] Furthermore, in the embodiment, the shock absorber 10 is a single-tube shock absorber, but the damping force generating valve 24 can also be applied to a double-tube shock absorber.

[0081] Symbol Explanation

[0082] 2a-First blade, 2b-Second blade, 2c-Third blade, 2d-Fourth blade, 2e-Fifth blade, 4b, 4c, 4d, 4e-Notch section, 10-Shock absorber, 12-Cylinder block, 18-Piston, 20-Damping force generating valve, 24-Damping force generating valve, 52-Opposing part, 54-Leaf valve, 55-Free end, G1-Clearance.

Claims

1. A shock absorber, characterized in that, include: Cylinder block; and A piston, which reciprocates and fits into the inner wall of the cylinder. The piston has a damping force generating valve that generates a damping force corresponding to the piston's velocity. The damping force generating valve has: An annular vane valve, which allows axial deflection of the piston to both sides with one of its outer and inner circumferences as a free end; and An annular opposing portion is provided, spaced apart from the free end of the blade valve. The vane valve has: First blade; The second blade is stacked on one side of the axial direction of the first blade; and The third blade is stacked on the opposite side of the axial direction of the first blade. The second blade and the third blade each have a notch at their free ends.

2. The shock absorber according to claim 1, characterized in that, The second blade and the third blade each have multiple notches at their free ends.

3. The shock absorber according to claim 1 or 2, characterized in that, The vane valve also has: The fourth blade is stacked on one side of the axial direction of the second blade; and The fifth blade is stacked on the opposite side of the axial direction of the third blade. The fourth and fifth blades each have a notch at their free ends. The notch of the fourth blade is positioned to overlap with the notch of the second blade. The notch of the fifth blade is positioned to overlap with the notch of the third blade.

4. The shock absorber according to claim 3, characterized in that, The width of the notch in the fourth blade is greater than the width of the notch in the second blade. The width of the notch in the fifth blade is greater than the width of the notch in the third blade.

5. The shock absorber according to claim 1 or 2, characterized in that, The outer periphery of the leaf valve is the free end. The vane valve also has: The fourth blade is stacked on one side of the axial direction of the second blade; and The fifth blade is stacked on the opposite side of the axial direction of the third blade. The first blade, the second blade, and the third blade all have the same outer diameter. The outer diameters of the fourth and fifth blades are each smaller than the outer diameter of the first blade. When viewed from the axial direction, the fourth blade does not overlap with the notch of the second blade. When viewed from the axial direction, the fifth blade does not overlap with the notch of the third blade.

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