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Abstract

The shock absorber (10; 10A; 10B) includes a cylinder (17), a piston (30), a piston portion spring (25) biasing the flow passage (31a) of the piston (30) in a direction to close the flow passage (31a), and a slide spring receiving member (40; 40A; 40B) disposed between the piston portion spring (25) and the piston (30) so as to be displaceable in a direction along the axis (CL). The piston (30) includes a piston body (31) and a stacked valve (33). The slide spring receiving member (40; 40A; 40B) includes an abutment surface (42a; 42Aa; 42Ba) against which the stacked valve (33) can abut. An imaginary plane (S1; S3) formed by connecting the portion of the abutment surface (42a; 42Aa; 42Ba) closest to the axis (CL) to the radially outer end is inclined with respect to a vertical plane (S2) extending radially from the axis (CL).

Description

[Technical field]

[0001] The present invention relates to a shock absorber. [Background technology]

[0002] For example, many vehicles such as motorcycles are provided with shock absorbers to attenuate vibrations from the road surface. Patent Document 1 discloses a conventional technique related to shock absorbers.

[0003] The shock absorber disclosed in Patent Document 1 includes a cylindrical cylinder, a piston provided inside the cylinder, a spring biasing the piston in a direction to close the flow path, and a sliding spring support member provided between the piston and the spring so as to be displaceable in the axial direction and which transmits the biasing force of the spring to the piston.

[0004] The shock absorber disclosed in Patent Document 1 can provide characteristics that increase the rise of the damping force at low speeds and make the damping force as gentle as possible at high speeds. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Utility Model Application Publication No. 63-180751 Summary of the Invention [Problem to be solved by the invention]

[0006] It is known that the damping force characteristics affect the ride comfort of a vehicle. If more arbitrary damping force characteristics can be generated, the ride comfort of the vehicle can be improved, which is preferable. An object of the present invention is to provide a shock absorber that can generate more arbitrary damping force characteristics. [Means for solving the problem]

[0007] As a result of intensive research, the inventors have found that by tilting the contact surface of the slide spring receiving member with which the laminated valve can come into contact with respect to a vertical surface extending in the radial direction from the axis line as the center, the amount of displacement of the laminated valve can be adjusted more finely, and more arbitrary damping force characteristics can be generated. The present invention was completed based on this finding.

[0008] The present disclosure will be described below.

[0009] According to the present disclosure, there is provided a shock absorber comprising: a cylinder having a generally cylindrical shape and filled with a working fluid; a piston provided inside the cylinder and dividing the interior of the cylinder into a first chamber and a second chamber; a piston spring which is formed inside the piston and biases a flow path through which the working fluid flows in a direction to close; and a slide spring support member which is provided between the piston spring and the piston and is displaceable in a direction along the axis of the cylinder and transmits the biasing force of the piston spring to the piston, wherein the piston comprises a piston body having a flow path therein through which the working fluid can pass, and a stacked valve which biases one end of the flow path in a direction to close the flow path and is formed by stacking a plurality of plate-shaped valves, the slide spring support member including an abutment surface against which the stacked valve can abut, and when a plane formed by connecting a portion of the abutment surface closest to the axis to an end portion on the radially outer side is taken as a virtual plane, the virtual plane is inclined with respect to a vertical plane extending in the radial direction about the axis. Effect of the Invention

[0010] According to the present invention, it is possible to provide a shock absorber capable of generating more arbitrary damping force characteristics. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view of a main portion of a shock absorber according to a first embodiment of the present invention. [Diagram 2] 2 is an enlarged view of a piston and a spring receiving member shown in FIG. 1. [Diagram 3]FIG. 3 is an enlarged view of the laminated valve shown in FIG. 2 in a deformed state. [Figure 4] 2 is a diagram illustrating the damping force characteristics of the shock absorber shown in FIG. 1. [Diagram 5] FIG. 6 is an enlarged view of a main portion of a shock absorber according to a second embodiment of the present invention. [Figure 6] 6 is a diagram illustrating the damping force characteristics of the shock absorber shown in FIG. 5. FIG. [Figure 7] FIG. 11 is an enlarged view of a main portion of a shock absorber according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Note that the embodiments shown in the accompanying drawings are merely examples of the present invention, and the present invention is not limited to these embodiments.

[0013] <Example 1> Please refer to Fig. 1. Fig. 1 shows a shock absorber 10 that constitutes a main part of a front fork. The front fork is provided at the front of a saddle-ride type vehicle and suppresses the transmission of vibrations received from the road surface to the vehicle body.

[0014] The shock absorber 10 is used by bridging the vicinity of the head pipe of a motorcycle to the front wheel. When a motorcycle is traveling, vibrations are input from the front wheel due to the influence of unevenness of the road surface, etc. At that time, the shock absorber 10 compresses and expands, generating a damping force.

[0015] The shock absorber 10 has as its main components a cylindrical outer tube 11 extending downward from the head pipe of the motorcycle toward the front wheel, a cylindrical inner tube 12 extending upward from the front wheel toward the head pipe with its tip inserted inside the outer tube 11, and a coil spring 13 that biases the outer tube 11 and inner tube 12 in directions separating them from each other.

[0016] The space enclosed by the outer tube 11 and the inner tube 12 is filled with oil as a working fluid. In addition, seals 14 and 15 are provided between the inner circumferential surface of the tip of the outer tube 11 and the outer circumferential surface of the inner tube 12 to prevent the oil from leaking out to the outside.

[0017] The shock absorber 10 has an outer tube lid portion 16 that closes the upper end (terminal end) of the outer tube 11, and a cylindrical cylinder 17 that is disposed inside the outer tube 11 on the coaxial line CL.

[0018] The shock absorber 10 also has an axle holder closing the lower end (terminal end) of the inner tube 12, a piston rod 22 extending from the axle holder along the axis CL, and a piston 30 provided at the tip of the piston rod 22 and through which oil can pass during compression and extension. The tip of the piston rod 22 and the piston 30 are inserted inside the cylinder 17. When the shock absorber 10 expands and contracts, the piston rod 22 and the piston 30 are displaced relative to the cylinder 17. When displaced, oil flows inside the piston 30, generating a damping force.

[0019] Refer to Fig. 2. On the outer periphery of the tip of the piston rod 22, there are provided a piston spring 25 which biases the piston 30 in the closing direction, a cylindrical collar 26, a slide spring receiving member 40 which is slidable on the outer periphery of this collar 26 and transmits the biasing force of the piston spring 25 to the piston 30, a nut 28 which prevents the piston 30 from coming out, and a washer 29 which is sandwiched between this nut 28 and the piston 30.

[0020] Please refer to Fig. 1. The piston 30 divides the inside of the cylinder 17 into a first chamber R1 and a second chamber R2.

[0021] Please refer to FIG. 2. The piston rod 22 has a hole along the axis, allowing oil to pass through. The piston rod 22 has a rod-side spring receiving portion 22a and a stopper portion 22b formed at a portion where the outer diameter changes. The rod-side spring receiving portion 22a and the stopper portion 22b each expand in the radial direction about the axis CL and have a substantially O-shape. The rod-side spring receiving portion 22a receives an end of the piston portion spring 25. The stopper portion 22b receives an end of the collar 26 and restricts movement when the slide spring receiving member 40 comes into contact with it.

[0022] The portion between the rod-side spring receiving portion 22a and the stopper portion 22b of the piston rod 22 is a spring guide portion 22c that guides the piston spring 25 and prevents it from falling. The outer diameter of the spring guide portion 22c is set to be slightly smaller than the inner diameter of the piston spring 25.

[0023] The tip of the piston rod 22 is formed into a male thread, and a nut 28 is fastened to it.

[0024] The piston 30 has a piston body 31 having a flow path 31a therein through which the working fluid can pass, a seal 32 fixed to the outer peripheral surface of the piston body 31 and whose outer peripheral surface abuts the inner peripheral surface of the cylinder 17 (see Figure 1), a compression side laminated valve 33 (laminate valve 33) that is biased in a direction to close an end (one end) of the flow path 31a and opens during a compression stroke, and an extension side laminated valve 34 that is biased in a direction to close a tip (other end) of the flow path 31a and opens during an extension stroke.

[0025] For example, when a motorcycle runs over a step, a compressive force is applied to the shock absorber 10, and the piston 30 is displaced as shown by the outline arrow 51. This causes oil to flow into the flow passage 31a as shown by the arrow 52, ​​displacing the compression side laminated valve 33 and / or the slide spring support member 40. At this time, a damping force is generated.

[0026] After the shock absorber 10 is compressed, the force of the coil spring 13 (see FIG. 1) acts on the shock absorber 10 in the expanding direction, displacing the piston 30 as shown by the outlined arrow 53. This causes oil to flow into the flow passage 31a as shown by the arrow 54, displacing the compression side laminated valve 33 and / or the slide spring support member 40. At this time, a damping force is generated.

[0027] The compression side laminated valve 33 and the expansion side laminated valve 34 may be well-known laminated valves, each of which is formed by laminating a plurality of metal plate valves that are elastically deformable in the axial direction. The forces required for the compression side laminated valve 33 and the expansion side laminated valve 34 to open the flow passage 31a may be set to be the same or different.

[0028] For example, a compression coil spring is used as the piston spring 25. The biasing force of the piston spring 25 may be set so that the compression side laminated valve 33 is displaced before the slide spring support member 40, or the slide spring support member 40 is displaced before the compression side laminated valve 33.

[0029] The collar 26 is formed of, for example, a resin cylinder. The collar 26 is sandwiched and fixed between the stopper portion 22b and the piston body 31. In addition to the slide spring receiving member 40, the compression side laminated valve 33 is provided on the outer periphery of the collar 26. In other words, the compression side laminated valve 33 and the slide spring receiving member 40 are provided slidably on the outer periphery of the collar 26.

[0030] The slide spring receiving member 40 has a spring receiving tubular portion 41 formed in a cylindrical shape so as to surround the collar 26, and a flange portion 42 extending radially from the tip of the spring receiving tubular portion 41.

[0031] The outer diameter of the spring receiving tubular portion 41 is approximately the same as the outer diameter of the spring guide portion 22c, and is slightly smaller than the inner diameter of the piston spring 25. The spring receiving tubular portion 41 guides the piston spring 25 and prevents it from falling over.

[0032] One surface of the flange portion 42 is a contact surface 42a with which the compression side laminated valve 33 can come into contact, and the other surface is a slider side spring receiving portion 42b that receives the piston portion spring 25.

[0033] The contact surface 42a is configured by an inclined surface that continues radially outward from the axis CL and moves away from the piston body 31. In other words, the contact surface 42a includes a tapered portion that is inclined with respect to the vertical plane S2. In other words, when a plane formed by connecting the portion of the contact surface 42a closest to the axis CL to the radially outer end is defined as a virtual plane S1 (in the shock absorber 10, the virtual plane S1 coincides with the contact surface 42a), the virtual plane S1 can be said to be inclined with respect to the vertical plane S2 that spreads in the radial direction with the axis CL as the center. The reason will be described later.

[0034] The contact surface 42a may be inclined in the opposite direction. That is, the contact surface 42a may be inclined so as to approach the piston body 31 as it moves away radially outward from the axis CL. The contact surface 42a may also be a curved surface whose inclination changes continuously or a stepped surface whose inclination changes stepwise, and is not limited to a flat surface. Furthermore, these shapes may be combined, and any shape may be used according to the characteristics of the damping force to be generated.

[0035] The operation of the shock absorber 10 will now be described.

[0036] For example, when the piston 30 rises inside the cylinder 17 (see FIG. 1), oil flows in the flow passage 31a as shown by the arrow 52. A downward force is applied to the compression side laminated valve 33 by the hydraulic pressure of this oil.

[0037] Please refer to Fig. 3. Fig. 3 shows the contraction side laminated valve 33 in a state of elastic deformation due to hydraulic pressure. When the biasing force of the piston portion spring 25 is set so that the contraction side laminated valve 33 is displaced before the slide spring support member 40, the slide spring support member 40 is displaced by further application of hydraulic pressure.

[0038] Please also refer to FIG. 4. FIG. 4 shows a graph showing the relationship between piston speed and damping force. The horizontal axis represents piston speed, and the vertical axis represents damping force. Since the cross-sectional area of ​​flow path 31a (see FIG. 2) inside piston 30 is constant, it can also be said that the graph shows the relationship between oil flow rate and damping force. According to shock absorber 10, the damping force is increased significantly in the region where piston 30 starts to move, and thereafter, the damping force also increases in proportion to the increase in piston speed.

[0039] By making the contact surface 42a a tapered surface that is spaced apart from the piston body 31 (see FIG. 2), the amount of displacement of the compression side laminated valve 33 can be made larger than when the contact surface 42a is a surface perpendicular to the axis (see the perpendicular surface S2). The change in the amount of displacement of the compression side laminated valve 33 changes the characteristics of the damping force. In other words, the damping force can be adjusted by changing the shape of the contact surface 42a.

[0040] In addition, the characteristics of the damping force can also be changed by setting the biasing force of the piston portion spring 25 so that the slide spring receiving member 40 is displaced before the compression side laminated valve 33 .

[0041] <Example 2> Next, a second embodiment will be described with reference to the drawings.

[0042] Please refer to Fig. 5. In the shock absorber 10A according to the second embodiment, the shape of the flange portion 42A of the slide spring receiving member 40A is different from the shape of the flange portion 42 shown in Fig. 3. The other basic configuration is common to the shock absorber 10 (see Fig. 2). For the configuration common to the shock absorber 10, the reference numerals are used and detailed description is omitted as appropriate.

[0043] The contact surface 42Aa in contact with the compression side laminated valve 33 has an outermost portion protruding toward the piston body 31 (see FIG. 2). In other words, the contact surface 42Aa includes a portion P2 that protrudes to a portion closer to the piston body 31 than the portion closest to the axis line CL (see FIG. 2).

[0044] If a plane formed by connecting the portion of the contact surface 42Aa closest to the axis line CL to the radially outer end is defined as a virtual plane S3, it can be said that the virtual plane S3 is inclined with respect to a vertical plane S2 extending in the radial direction about the axis line CL.

[0045] Of the compression side laminated valve 33, the valve abutting against the protruding portion P2 has its displacement restricted as compared with the case where the abutment surface 42a is formed on the vertical surface S2.

[0046] As described above, the contact surface 42Aa may be provided with a plurality of protruding portions P2 so as to have a stepped shape that gradually approaches the piston body 31.

[0047] Please also refer to Fig. 6. Fig. 6 shows a graph showing the relationship between piston speed and damping force. According to the shock absorber 10A, the change in damping force relative to the change in piston speed is large in the slow and fast piston speed regions, and the change in damping force relative to the change in piston speed is small in the region between these two.

[0048] <Example 3> Next, a third embodiment will be described with reference to the drawings.

[0049] Please refer to Fig. 7. In the shock absorber 10B according to the third embodiment, the shape of the flange portion 42B of the slide spring receiving member 40B differs from the shape of the flange portion 42 shown in Fig. 2 and the flange portion 42A shown in Fig. 5. The other basic configuration is common to the shock absorbers 10 (see Fig. 2) and 10A (see Fig. 5). The same reference numerals will be used for the configuration common to the shock absorbers 10 and 10A, and detailed explanations will be omitted as appropriate.

[0050] The contact surface 42Ba that contacts the compression side laminated valve 33 is configured with a tapered portion P1 and a protruding portion P2. This makes it possible to generate a damping force characteristic different from the above-mentioned damping force characteristic.

[0051] The shock absorbers 10, 10A, and 10B described above will be summarized below.

[0052] Referring to Fig. 1, first, the shock absorber 10 has a cylinder 17 that is substantially cylindrical and filled with a working fluid, and a piston 30 that is provided inside the cylinder 17 and divides the inside of the cylinder 17 into a first chamber R1 and a second chamber R2.

[0053] 2, the shock absorber 10 further includes a piston spring 25 that is formed inside the piston 30 and biases the flow path 31a, through which the working fluid flows, in a direction to close the flow path, and a slide spring receiving member 40 that is disposed between the piston spring 25 and the piston 30 so as to be displaceable in a direction along the axis CL of the cylinder 17 and transmits the biasing force of the piston spring 25 to the piston 30.

[0054] The piston 30 has a piston body 31 having a flow path 31a therein through which the working fluid can pass, and a compression side laminated valve 33 which is biased in a direction to close one end of the flow path 31a and which is made up of multiple plate-shaped valves stacked on top of each other.

[0055] The slide spring receiving member 40 includes a contact surface 42a against which the compression side laminated valve 33 can come into contact. When a plane formed by connecting a portion of the contact surface 42a closest to the axis line CL to an end portion on the radially outer side is defined as a virtual plane S1, the virtual plane S1 is inclined with respect to a vertical plane S2 extending in the radial direction about the axis line CL.

[0056] The imaginary plane S1 is inclined with respect to the vertical plane S2 extending in the radial direction around the axis CL. This allows the displacement amount of the compression side laminated valve 33 to be set more freely than when the contact surface 42a is along the vertical plane S2. The generated damping force can be adjusted by controlling the displacement amount of the compression side laminated valve 33. Specifically, the compression side laminated valve 33 is formed by stacking a plurality of plate-shaped valves having a large diameter on a plate-shaped valve having a small diameter that contacts the slide spring receiving member 40. By adjusting the size of the plate-shaped valve having a small diameter and the contact position with the contact surface 42a, a complex damping force characteristic can be obtained compared to when a single plate-shaped valve is used. The imaginary plane S1 of the contact surface 42a is inclined with respect to the vertical plane S2 extending in the radial direction around the axis CL, allowing the displacement amount of the compression side laminated valve 33 to be adjusted more freely. Furthermore, since the contact surface 42a is provided on the slide spring receiving member 40, the slide spring receiving member 40 can slide while maintaining a large displacement amount of the compression side laminated valve 33. The synergistic effect of these effects makes it possible to generate more arbitrary damping force characteristics. It is possible to provide a shock absorber that can generate more arbitrary damping force characteristics. The same applies to shock absorber 10A (see FIG. 5) and shock absorber 10B (see FIG. 7).

[0057] Secondly, the first shock absorber 10 has a stopper portion 22b that is provided so as to be able to come into contact with the slide spring receiving member 40 and that restricts the displacement of the slide spring receiving member 40 by the slide spring receiving member 40 coming into contact therewith.

[0058] The amount of displacement of the slide spring receiving member 40 can be set as desired by changing the position of the stopper portion 22b. This makes it possible to generate more desired damping force characteristics. The same applies to the shock absorber 10A (see FIG. 5) and the shock absorber 10B (see FIG. 7).

[0059] Thirdly, in the first or second shock absorber 10, the contact surface 42a includes a tapered portion that is inclined with respect to the vertical plane S2. For the tapered portion, a proportional damping force characteristic is obtained.

[0060] See Fig. 5. Fourthly, in any of the first to third shock absorbers 10A, the contact surface 42Aa includes a portion P2 that protrudes to a portion closer to the piston body 31 (see Fig. 2) than the portion closest to the axis CL. This suppresses the amount of opening of the compression side stacked valve 33, thereby obtaining a characteristic that makes it easier for the damping force to increase (progressive characteristic).

[0061] See FIG. 2. Fifth, in any one of the first to fourth shock absorbers 10, the biasing force of the piston spring 25 is set so that the compression side laminated valve 33 is displaced before the slide spring support member 40. As a result, the compression side laminated valve 33 opens in the low piston speed range, so that the damping force characteristics in the low piston speed range can be made smooth, and such needs can be met. Also, in the high speed range, the slide spring support member 40 is displaced while maintaining the displacement of the compression side laminated valve 33, so that the damping force characteristics can be linked to the damping force characteristics in the low speed range. The same applies to the shock absorber 10A (see FIG. 5) and the shock absorber 10B (see FIG. 7).

[0062] Sixth, in any one of the first to fourth shock absorbers 10, the biasing force of the piston spring 25 is set so that the slide spring support member 40 is displaced before the compression side laminated valve 33. As a result, the slide spring support member 40 is displaced in the low piston speed range, so that the damping force characteristic in the low piston speed range can be a single damping force characteristic. In the high piston speed range, the compression side laminated valve 33 is displaced, so that a smooth damping force characteristic can be obtained, and such needs can be met. The same applies to the shock absorber 10A (see FIG. 5) and the shock absorber 10B (see FIG. 7).

[0063] Seventh, in any of the first to sixth shock absorbers 10, the slide spring receiving member 40 includes a spring receiving tubular portion 41 formed in a cylindrical shape so as to surround the axis line CL. The spring receiving tubular portion 41 extends along the inside of the piston spring 25.

[0064] Since the slide spring receiving member 40 can be displaced along the axis line CL more reliably, the set damping force characteristics can be generated more reliably. Also, the piston portion spring 25 can be prevented from falling. The same applies to the shock absorber 10A (see FIG. 5) and the shock absorber 10B (see FIG. 7).

[0065] Although the shock absorber according to the present invention has been described as being applied to an inverted front fork of a motorcycle, it can also be applied to an upright front fork or rear cushion. In addition, the vehicle on which it is mounted is not limited to motorcycles, but can also be applied to saddle-type vehicles such as three-wheeled vehicles and other vehicles.

[0066] Furthermore, the cylinder is not limited to being provided inside the inner tube. That is, the outer tube or the inner tube may be the cylinder of the present invention as long as it is a cylindrical body with a piston in contact with its inner peripheral surface.

[0067] In addition, the piston has been described as being movable axially inside the cylinder, but it may be fixed inside the cylinder, such as a piston provided at the end of a front fork or a piston used in the damping force generating part of a rear cushion.

[0068] In other words, the present invention is not limited to the examples as long as the functions and effects of the present invention are achieved. [Industrial Applicability]

[0069] The shock absorber of the present invention is suitable for use in the front fork of a two-wheeled vehicle. [Explanation of symbols]

[0070] 10; 10A; 10B... shock absorber, 17... cylinder, 22b... stopper portion, 25... piston portion spring, 30... piston, 31... piston body, 31a... flow path, 33... compression side laminated valve (laminated valve), 40; 40A; 40B... slide spring receiving member, 42a; 42Aa; 42Ba... abutment surface, R1... first chamber, R2... second chamber, S1; S3... imaginary surface, S2... vertical surface, P1... tapered portion, P2... protruding portion, CL... axis

Claims

1. A cylinder having a generally cylindrical shape and filled with a working fluid; a piston provided inside the cylinder and dividing the interior of the cylinder into a first chamber and a second chamber; a piston spring that biases a flow path formed inside the piston in a direction to close the flow path through which the working fluid flows; a slide spring receiving member disposed between the piston spring and the piston so as to be displaceable in a direction along the axis of the cylinder and transmitting the biasing force of the piston spring to the piston, The piston is A piston body having a flow passage therein through which the working fluid can pass; a laminated valve configured by stacking a plurality of plate-shaped valves, the laminated valve being biased in a direction to close one end of the flow path; the slide spring receiving member includes an abutment surface against which the stacked valve can abut, when a surface formed by connecting a portion of the contact surface closest to the axis to an end portion on the radially outer side is defined as a virtual surface, the virtual surface is inclined with respect to a vertical plane extending in a radial direction about the axis, The contact surface includes a portion that protrudes to a portion closer to the piston body than a portion closest to the axis.

2. 2. The shock absorber according to claim 1, The slide spring receiving member has a stopper portion that is capable of contacting the slide spring receiving member and that restricts the displacement of the slide spring receiving member by the slide spring receiving member contacting the stopper portion.

3. 2. The shock absorber according to claim 1, The biasing force of the piston spring is set so that the laminated valve is displaced before the slide spring receiving member.

4. 2. The shock absorber according to claim 1, The slide spring receiving member includes a spring receiving tubular portion formed in a tubular shape so as to surround the axis, The spring receiving tubular portion extends along the inside of the piston spring.