Shock absorber and method of manufacturing same

Abstract

A shock absorber (10) has a cylinder (40), a rod support member (50), a piston rod (60), a coil spring (15), and an actuator (70). The actuator (70) has: a first case (71) that is fixed to the rod support member (50) and seals oil; a second case (73) that is detachably provided to the first case (71) so as to extend the first case (71); and a coil (74) that is housed in the first case (71). The length (L1) from the bottom of the rod support member (50) to the tip of the first case (71) is shorter than the inner diameter (D1) of the coil spring (15).

Description

Shock absorber and method for manufacturing the same

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

[0002] Many saddle-riding type vehicles are provided with a shock absorber called a rear cushion. As a prior art related to shock absorbers, there is a technique disclosed in Patent Document 1.

[0003] As shown in Patent Document 1, the shock absorber includes a cylinder, a piston rod having a rod radial hole portion penetrating in the radial direction, a piston provided at the tip of the piston rod, a coil spring biasing the cylinder and the piston rod in a separating direction, a rod support member supporting the other end of the piston rod, a push rod displaceably provided inside the piston rod and capable of adjusting the opening degree of the rod radial hole portion, an actuator provided on the rod support member for adjusting the position of the push rod, and a conversion portion for transmitting the driving force of this actuator to the push rod.

[0004] By adjusting the opening degree of the rod radial hole portion, the damping force can be adjusted.

[0005] Japanese Patent Application Laid-Open No. 2013-242016

[0006] In the assembly of such a shock absorber, if the cylinder, piston rod, piston, and rod support member can be temporarily assembled and the coil spring can be assembled after sealing the oil, the assembly work becomes easy and is preferable. For example, when injecting oil after assembling the coil spring, it is necessary to inject the oil while receiving the biasing force of the coil spring, or to inject the oil while avoiding the coil spring. Or, when providing the coil spring in a state where the oil is not sealed, it is necessary to attach the coil spring while paying attention to oil leakage and the like.

[0007] However, when attempting to assemble in this way in the shock absorber disclosed in Patent Document 1, the length from the rod support member to the actuator is larger than the inner diameter of the coil spring, and the coil spring cannot be inserted in the temporarily assembled state.

[0008] The present invention aims to provide a shock absorber that is easy to assemble.

[0009] As a result of diligent research, the inventors have found that by making the length from the bottom of the rod support member to the tip of the first case shorter than the inner diameter of the coil spring, and by further attaching a second case for the required length, it is possible to provide a shock absorber that is easy to assemble. That is, by attaching the first case, the coil spring can be attached while preventing oil leakage, and the second case can be attached after the coil spring has been attached. The present invention was completed based on this finding.

[0010] The following describes this disclosure.

[0011] According to one of the present disclosures, a shock absorber is provided, comprising: a substantially cylindrical cylinder filled with oil; a rod support member provided to be displaceable relative to the cylinder; a piston rod supported by the rod support member and having its tip inserted into the cylinder; a coil spring biasing the piston rod toward the direction toward the retraction of the cylinder; and an actuator provided on the rod support member and having a pin that acts linearly toward a direction opposite to the axis of the cylinder, wherein the actuator comprises: a first case fixed to the rod support member and sealing the oil; a second case detachably provided on the first case so as to extend the first case; and a coil housed in the first case, wherein the length from the bottom of the rod support member to the tip of the first case is shorter than the inner diameter of the coil spring.

[0012] Furthermore, according to other aspects of this disclosure, a method for manufacturing a shock absorber is provided, comprising: a preparation step of preparing a cylinder, a rod support member, a piston rod, a coil spring, a first case, a second case, and a coil; a temporary assembly step of inserting the tip of the piston rod into the inside of the cylinder, supporting the other end of the piston rod with the rod support member, attaching the first case to the rod support member, and obtaining a temporary assembly; a coil spring mounting step of providing the coil spring along the outer circumference of the temporary assembly from the rod support member toward the cylinder; a second case mounting step of attaching the second case to the first case while the coil spring is attached to the outer circumference of the cylinder; and a coil mounting step of attaching the coil to the first case to which the second case is attached.

[0013] According to this disclosure, it is possible to provide a shock absorber that is easy to assemble.

[0014] This is a cross-sectional view of a shock absorber according to an embodiment. This is a perspective view of the piston rod, piston, rod support member, and valve shown in Figure 1. This is an enlarged view of the actuator and valve shown in Figure 1. This is a perspective view of the actuator shown in Figure 2 as seen from the conversion unit side. This is an enlarged view of the actuator shown in Figure 1. This is a diagram illustrating the operation of the actuator and valve shown in Figure 3. This is a diagram illustrating the temporary assembly of the shock absorber shown in Figure 1 before manufacturing. Figure 8A illustrates the coil spring mounting process, Figure 8B illustrates the second case mounting process, and Figure 8C illustrates the coil mounting process.

[0015] Embodiments of the present invention will be described below with reference to the attached drawings. However, the present invention is not limited to these embodiments.

[0016] Embodiments of the present invention will be described below with reference to the attached drawings. Note that the embodiments shown in the attached drawings are examples of the present invention, and the present invention is not limited to these embodiments.

[0017] <Example> Refer to Figure 1. Figure 1 shows a rear cushion as a shock absorber 10. The rear cushion is installed from the rear wheels to the body of a saddle-type vehicle and dampens energy such as vibrations received from the road surface.

[0018] Refer to Figure 2 as well. The shock absorber 10 includes a substantially cylindrical cylinder 40 connected to one member (for example, the vehicle body) and filled with oil, a rod support member 50 connected to the other member (for example, the rear wheel) and movable relative to the cylinder 40, a substantially cylindrical piston rod 60 with its tip (upper end) inserted into the inside of the cylinder 40, a piston 14 provided near the tip of the piston rod 60 and dividing the inside of the cylinder 40 into a first chamber R1 and a second chamber R2, a coil spring 15 that biases the piston rod 60 in the direction of retraction from the cylinder 40, and an actuator 70 provided on the rod support member 50.

[0019] Refer to Figures 3 and 4. The shock absorber 10 further includes a first transmission member 17 which is linearly displaced when the actuator 70 is operated, a conversion unit 80 which is in contact with the first transmission member 17 and rotatably mounted, a second transmission member 19 which is in contact with the conversion unit 80 and is linearly displaced when the actuator 70 is operated, a push rod 21 which is in contact with the second transmission member 19 and is displaceably mounted inside the piston rod 60, and a part provided at the tip of the push rod 21 that extends to the outside of the piston rod 60. The valve has a protruding member 22, a valve contact member 23 that abuts against the protruding member 22 and surrounds the outer circumference of the piston rod 60, a valve 24 that abuts against the valve contact member 23 and is provided to be displaceable relative to the piston rod 60, a receiving member support portion 25 fixed above the valve 24, a valve spring receiving member 26 fixed to the receiving member support portion 25, and a valve spring 27 with one end abutting against the valve spring receiving member 26 and the other end abutting against the valve 24.

[0020] Refer to Figure 1. The shock absorber 10 further includes a sub-tank 31 integrally formed with the cylinder 40 through which oil corresponding to the volume of the piston rod 60 flows when the piston rod 60 enters, a cylinder cover 32 that closes the lower end of the cylinder 40, a guide member 33 provided at the lower part of the cylinder 40 to guide the piston rod 60, a piston retaining nut 34 provided at the tip of the piston rod 60 to prevent the piston 14 from coming out, a tip receiving member 35 fixed to the outer circumference of the cylinder 40 to receive the tip of the coil spring 15, an end receiving member 36 fixed to the outer circumference of the rod support member 50 to receive the other end of the coil spring 15, a bump rubber 37 fixed to the end receiving member 36 to prevent contact between the cylinder 40 and the rod support member 50, and a rod retaining nut 38 that abuts against the rod support member 50 and prevents the piston rod 60 from coming out of the rod support member 50.

[0021] The cylinder 40 is formed in a bottomed cylindrical shape, and a cylinder mounting portion 41 for attachment to one of the members is integrally formed at its upper end. A male threaded portion 42 is formed on a part of the outer circumferential surface of the cylinder 40. A tip receiving member 35 is fastened to the cylinder threaded portion 42.

[0022] The upper end of the cylinder 40 is connected to the sub-tank 31. As the shock absorber 10 expands and contracts, oil in the first chamber R1 flows into the sub-tank 31, and oil in the sub-tank 31 flows into the first chamber R1.

[0023] Refer to Figure 5. The rod support member 50 has a support member mounting portion 51 for attachment to the other member, a storage hole portion 52 which is a bottomed hole housing the actuator 70, the first transmission member 17, the conversion portion 80, and the second transmission member 19, and a support member female thread portion 53 which is female threaded and to which the other end of the piston rod 60 is fastened.

[0024] The storage hole 52 has a larger inner diameter at its tip and a smaller inner diameter near the bottom. The side of the storage hole 52 and the bottom of the female threaded portion 53 of the support member are connected, and the base end of the push rod 21 faces the storage hole 52. The oil filling the inside of the cylinder 40 extends to the inside of both the storage hole 52 and the female threaded portion 53 of the support member.

[0025] Refer to Figure 3. The piston rod 60 has a first rod portion 61 located inside the cylinder 40 and extending across the first chamber R1 (see Figure 1) and the second chamber R2, and a second rod portion 62 fastened to the first rod portion 61 and extending from the second chamber R2 to the rod support member 50.

[0026] The first rod portion 61 includes a first axial hole portion 61a, which is a bottomed hole opened from the tip along the axis CL1 of the cylinder 40; a plurality of rod radial hole portions 61b, which penetrate radially from the first axial hole portion 61a; a second rod fastening portion 61c, which is formed in the shape of an internal screw and through which the second rod portion 62 is fastened; and a plurality of protruding member through-hole portions 61d, which are holes opened radially at a position facing the tip of the push rod 21 and through which the protruding member 22 passes.

[0027] The tip of the first axial hole 61a faces the first chamber R1 (see Figure 1). On the other hand, the rod radial hole 61b is located within the second chamber R2. When the actuator 70 is not energized, the rod radial hole 61b is closed by the valve 24.

[0028] The second rod portion 62 has a push rod storage hole portion 62a that penetrates axially. The push rod storage hole portion 62a is formed along the axis CL1 of the cylinder 40 and houses the push rod 21. The outer circumferential surface of the tip (one end) of the second rod portion 62 has a male threaded first rod fastening portion 62b which is fastened to the second rod fastening portion 61c. The outer circumferential surface of the base (other end) of the second rod portion 62 has a male threaded support member fastening portion 62c which is fastened to the support member female threaded portion 53. The other end of the second rod portion 62 is provided with a second rod seal member 62d which is in close contact with the rod support member 50 and suppresses oil leakage.

[0029] Refer to Figure 1. A well-known piston can be used for the piston 14. The piston 14 has multiple holes through which oil can pass during compression and extension, and a damping force is generated as the oil passes through each hole. The volumes of the first chamber R1 and the second chamber R2 change depending on the position of the piston 14.

[0030] Refer to Figure 5. The actuator 70 is, for example, a solenoid actuator that operates by energizing. The actuator 70 includes a first case 71 that forms the bottom, a pin unit 72 housed in the first case 71 and including a pin 72b whose tip abuts against the first transmission member 17, a substantially cylindrical second case 73 fastened to the first case 71, a coil 74 provided inside the first case 71 and the second case 73, a power supply unit 75 connected to an external power source that energizes the coil 74, and a C-shaped ring provided on the inner circumference of the first case 71, which is a retaining ring 76 that restricts the displacement of the pin unit 72 toward the coil 74. When the actuator 70 is not energized, the actuator 70 is located on one side (left side in the drawing) of the axis CL1 of the cylinder 40.

[0031] The first case 71 has a bottom plate portion 71a that constitutes the bottom plate, and a roughly cylindrical first case body portion 71b that rises from the bottom plate portion 71a. The first case body portion 71b forms a magnetic circuit and is made of a magnetic material.

[0032] The outer circumferential surface of the lower part of the first case body 71b is formed in a male thread shape and fastened to the storage hole 52. The outer circumferential surface of the tip of the first case body 71b is also formed in a male thread shape and fastened to the second case 73. Between the outer circumferential surface of the first case body 71b (the side surface of the first case 71) and the inner circumferential surface of the storage hole 52, a first case seal member 71c is provided to suppress oil leakage from the storage hole 52. The length L1 from the case 71 of the first case to the rod support member 50 is smaller than the inner diameter D1 of the coil spring 15.

[0033] The pin unit 72 includes a pin case 72a which is generally housed inside the first case 71, a round bar-shaped pin 72b which is provided in the pin case 72a so as to be able to move back and forth and whose tip abuts against the first transmission member 17, and a pin guide portion 72c which abuts against the outer circumferential surface of the pin 72b and also abuts against the inner circumferential surface of the pin case 72a.

[0034] A pin case sealing member 72d is provided on the outer circumferential surface of the base end of the pin case 72a, which abuts against the inner circumferential surface of the first case 71.

[0035] The pin 72b is positioned such that its axis CL2 intersects the axis CL1 of the cylinder 40 approximately perpendicularly.

[0036] The pin guide portion 72c is fixed to the outer circumference of the pin 72b and displaces together with the pin 72b.

[0037] The second case 73 has an inner circumferential surface formed in the shape of an internal screw on the outer circumference of the first case 71, and is fastened to the first case 71. The second case 73 forms a magnetic path and is made of a magnetic material.

[0038] The second case 73 has a rotation prevention part formed therein to prevent the power supply unit 75 from rotating. The rotation prevention part is made up of a slit formed on the edge of the second case 73, and a locking part extending from the power supply unit 75 is engaged with this slit, thereby preventing the power supply unit 75 from rotating.

[0039] The coil 74 has a coil support portion 74a that abuts the outer surface of the pin case 72a, and a coil body 74b formed by winding copper wire around the coil support portion 74a. One end of the coil body 74b is connected to a power supply unit 75, and power can be supplied through the power supply unit 75. It is preferable that the coil 74 and the power supply unit 75 are unitized. If they are unitized, installation becomes easier.

[0040] The power supply unit 75 includes a connector that can be connected to an externally provided power source.

[0041] Refer to Figure 4 as well. The base end of the first transmission member 17 abuts against the tip of the pin 72b. The tip of the first transmission member 17 has a larger outer diameter than the base end. A groove 17a is formed at the tip of the first transmission member 17, recessed in a roughly U-shape toward the pin 72b so as to pass through the axis CL2 of the pin 72b. The groove 17a clamps the other end of the conversion unit 80. The portion corresponding to the bottom of the groove 17a is formed in an arc-shaped cross-section, with the central part bulging the most toward the conversion unit 80 (see also Figure 5). The first transmission member 17 is displaced linearly, while the conversion unit 80 is provided to swing. Because the bottom of the groove 17a is formed in an arc shape, the other end of the conversion unit 80 can be brought into contact with the first transmission member 17 more reliably.

[0042] The conversion unit 80 has a rotating shaft portion 81 fixed to the storage hole portion 52, and a substantially V-shaped conversion unit body 82 rotatably mounted on the rotating shaft portion 81. With respect to the axis CL1 of the cylinder 40, the conversion unit 80 is almost entirely located on the other side (right side in the drawing) of the axis CL1. One end of the conversion unit body 82 is slightly located on one side of the axis CL1, but excluding that portion, it is located on the other side. In other words, it can be said that the actuator 70t0 and the conversion unit 80 are provided so as to straddle the axis CL1.

[0043] The rotating shaft portion 81 is constituted by a round bar. The rotating shaft portion 81 may be provided so as to be displaceable with respect to the housing hole portion 52 via a position adjusting mechanism. When the position of the rotating shaft portion 81 can be adjusted, the contact position between the first transmission member 17 and the conversion portion 80 and the contact position between the second transmission member 19 and the conversion portion 80 can be adjusted. As a result, the displacement amount of the push rod 21 with respect to the protruding amount of the pin 72b can be changed.

[0044] The conversion unit main body 82 has a receiving portion 82a that abuts against the groove portion 17a and receives the driving force of the actuator 70, a transmission portion 82b that abuts against the second transmission member 19 and transmits the driving force of the actuator 70, and a bent portion 82c that is located between the receiving portion 82a and the transmission portion 82b and is bent. A rotating shaft portion 81 is provided at the center of the bent portion 82c.

[0045] Note that the shape of the conversion unit main body 82 is not limited to a substantially V shape. For example, it may be in the shape of C, I, J, L, M, N, S, T, U, W, Z, or any other arbitrary shape. Also, the distances from the rotating shaft portion 81 to the receiving portion 82a and the transmission portion 82b may be the same or different as shown in the figure. For example, the length from the rotating shaft portion 81 to the receiving portion 82a may be made longer or shorter than the length from the rotating shaft portion 81 to the transmission portion 82b.

[0046] The second transmission member 19 is constituted by a plate-like member having a long hole opened at the center. Both ends of the second transmission member 19 are respectively formed in a concave shape and have a first contact concave portion 19a where the transmission portion 82b abuts and a second contact concave portion 19b where the base end of the push rod 21 abuts. Also, between the first contact concave portion 19a and the second contact concave portion 19b, there is a bypass portion 19c formed by a long hole so as to avoid the orbit of the pin 72b. A part of the second transmission member 19 is provided on the orbit of the pin 72b, while the portion overlapping the orbit of the pin 72b is a long hole-shaped bypass portion 19c, so that the second transmission member 19 does not interfere with the pin 72b.

[0047] Refer to FIG. 3. The push rod 21 is generally formed in a round bar shape, and its tip is formed with a small diameter. The tip portion formed with a small diameter penetrates the protruding member 22 and supports the protruding member 22 by a step formed by being formed with a small diameter. The axis of the push rod 21 coincides with the axis CL1 of the cylinder 40 and can be displaced along the axis CL1 of the cylinder 40.

[0048] The protruding member 22 protrudes from a plurality of locations in the radial direction from the axis CL1 of the cylinder 40. The tip of the protruding member 22 abuts against the valve contact member 23. When the push rod 21 rises, the protruding member 22 raises the valve contact member 23.

[0049] Refer to FIG. 2 together. The valve contact member 23 has a disk portion 23a that abuts against the protruding member 22 and is formed in a donut plate shape along the outer periphery of the piston rod 60, and a contact member cylinder portion 23b that extends vertically in the circumferential direction from the tip of the disk portion 23a.

[0050] The upper surface of the disk portion 23a abuts against the valve 24. Also, the tip of the contact member cylinder portion 23b surrounds the tip of the valve 24. Note that the disk portion 23a may not abut against the valve 24 and the contact member cylinder portion 23b may abut against the valve 24.

[0051] Refer to only FIG. 3. The valve 24 is formed in a substantially cylindrical shape along the outer peripheral surface of the piston rod 6 around the entire circumference, and has a closing portion 24a that closes the rod radial hole portion 61b, an opening portion formed intermittently in a notch shape at a position corresponding to the rod radial hole portion 61b to open the rod radial hole portion 61b, and a spring receiving portion 24c that is located between these closing portion 24a and opening portion 24b and receives the other end of the valve spring 27. The spring receiving portion 24c protrudes radially more than the closing portion 24a. [[ID=)13]]

[0052] The valve spring receiving member 26 is fastened to a receiving member support portion 25 whose inner peripheral surface is formed in a female screw shape and whose outer peripheral surface is formed in a male screw shape.

[0053] The valve spring 27 is formed by a coil spring. The valve spring 27 biases the valve 24 in a downward direction. This biasing force acts in a downward direction on the push rod 21 via the valve contact member 23 and the protruding member 22.

[0054] Refer to Figure 1. The cylinder cover portion 32 has a cover portion hole 32a that penetrates radially.

[0055] The guide member 33 is fixed inside the cylinder 40. The outer circumferential surface of the guide member 33 is provided with a guide member seal portion 33a to suppress oil leakage from inside the cylinder 40. Because the guide member seal portion 33a is provided, the oil inside the cylinder 40 does not flow into the cylinder lid portion 32.

[0056] The tip receiving member 35 is formed in a cylindrical shape, and its inner circumferential surface is formed in a female thread shape. The tip receiving member 35 is fastened to the cylinder's male thread portion 42.

[0057] The other end receiving member 36 is formed in a roughly C-shape. The other end receiving member 36 can be attached by pressing it against the outer surface of the rod support member 50 while spreading both ends of the C shape.

[0058] Next, I will explain the function of the buffer 10.

[0059] Refer to Figure 6. When current is applied to the coil 74, a magnetic force is generated, and the pin 72b is pushed out of the pin case 72a and moves forward. The forward-moving pin 72b pushes the first transmission member 17, causing the conversion unit body 82 to rotate and the second transmission member 19 to rise. The rising second transmission member 19 causes the push rod 21, the protruding member 22, the valve contact member 23, and the valve 24 to rise. In other words, the second transmission member 19 pushes up the valve 24 against the biasing force of the valve spring 27. As the valve 24 rises, the opening portion 24b moves to the outer circumference of the rod radial hole portion 61b. This state is called the open mode.

[0060] Refer to Figure 1 as well. In the open mode and during the compression stroke, some of the oil flows from the first chamber R1 to the first axial hole 61a and through the rod radial hole 61b. The oil that has passed through the rod radial hole 61b can flow into the second chamber R2. On the other hand, in the open mode and during the extension stroke, some of the oil flows from the second chamber R2 through the rod radial hole 61b and into the rod radial hole 61b. The oil that has flowed into the rod radial hole 61b flows into the first chamber R1.

[0061] When oil flows through the first rod portion 61, the flow rate of oil passing through the piston 14 decreases compared to when oil does not flow through the first rod portion 61. As a result, the damping force generated when the shock absorber 10 expands and contracts becomes smaller.

[0062] Refer to Figures 3 and 6. When the current is turned off to the coil 74 from the open mode, the magnetic force is no longer applied to the pin 72b. As a result, the valve 24 is pushed down by the biasing force of the valve spring 27, and the rod radial hole 61b is closed by the closing part 24a. The valve 24 also pushes down the valve contact member 23, which in turn pushes down the protruding member 22, the push rod 21, and the second transmission member 19. As the second transmission member 19 moves, the conversion unit body 82 rotates, the first transmission member 17 moves, and the pin 72b retracts toward the pin case 72a. This state is called the closed mode.

[0063] Refer only to Figure 3. In closed mode, the flow of oil from the second chamber R2 to the inside of the first rod, and the flow of oil from the inside of the first rod to the second chamber R2 are blocked. In closed mode, the flow rate of oil passing through the piston 14 increases compared to open mode. As a result, the damping force generated when the shock absorber 10 expands and contracts becomes larger.

[0064] Next, a description of the manufacturing method for the shock absorber 10 will be provided.

[0065] Refer to Figure 1. First, prepare the cylinder 40, the rod support member 50, the piston rod 60, the piston 14, the coil spring 15, the first case 71, the second case 73, the coil 74, and the circuit board 75a (see Figure 8C), which is a control board that forms part of the power supply unit 75 and controls the supply of power to the coil 74 (preparation step).

[0066] Refer to Figure 7. Next, the piston 14 is fixed to the tip of the piston rod 60, the piston 14 and the tip of the piston rod 60 are inserted into the cylinder 40, the other end of the piston rod 60 is supported by the rod support member 50, the first case 71 is attached to the rod support member 50, oil is filled into the cylinder 40, and a temporary assembly 10A is obtained (temporary assembly step).

[0067] Each step in the preliminary assembly process can be performed in any order. For example, the rod support member 50 may be attached to the piston rod 60 after the piston 14 and piston rod 60 have been inserted into the cylinder 40, or the piston 14 and piston rod 60 may be inserted into the cylinder 40 after the rod support member 50 has been attached to the piston rod 60.

[0068] Alternatively, the first case 71 may be attached with the piston rod 60 attached to the rod support member 50, or the piston rod 60 may be attached to the rod support member 50 with the first case 71 attached to the rod support member 50.

[0069] Furthermore, it is also possible to attach the cylinder 40 to the first rod portion 61 and insert it into the piston 14, attach the rod support member 50 to the other end of the second rod portion 62, and then connect the first rod portion 61 and the second rod portion 62.

[0070] On the other hand, it is preferable to fill the oil after attaching the piston 14 and piston rod 60 to the cylinder 40, attaching the rod support member 50 to the piston rod 60, and attaching the first case 71 to the rod support member 50. This allows subsequent work to be carried out while suppressing oil leakage.

[0071] Refer to Figure 1. Other components such as the cylinder cover 32, the front end receiving member 35, the other end receiving member 36, and the bump rubber 37 may be installed before or after the preparation and preliminary assembly processes. They may also be installed during the preparation and preliminary assembly processes. If a roughly C-shaped member like the other end receiving member 36 is used for the front end receiving member 35, it can be installed after the coil spring 15 is attached.

[0072] Refer to Figure 8A as well. Once the temporary assembly 10A is assembled, the coil spring 15 is installed along the outer circumference of the temporary assembly 10A, from the rod support member 50 toward the cylinder 40 (coil spring installation step). The diameter of the circle shown by the dashed line in Figure 8A is smaller than the inner diameter of the coil spring 15. Therefore, the coil spring 15 can be passed from the rod support member 50 toward the cylinder 40.

[0073] In this embodiment, the length from the tip of the pin unit 72 to the bottom of the rod support member 50 is also smaller than the inner diameter of the coil spring 15. In such cases, a pin mounting step may be performed to attach the pin unit 72 (pin 72b) to the first case 71 prior to the preliminary assembly step.

[0074] Furthermore, it is preferable that the corners of the bottom of the rod support member 50 are formed as a cut-off portion 54 to avoid the coil spring 15. This allows the use of a coil spring 15 with a smaller inner diameter, contributing to the miniaturization of the shock absorber 10.

[0075] Refer to Figures 1 and 8B. Next, with the coil spring 15 attached to the outer circumference of the cylinder 40, the second case 73 is attached to the first case 71 (second case attachment step).

[0076] Refer to Figures 1 and 8C. Next, the coil 74, which has the power supply unit 75 (substrate 75a) integrated into it, is attached to the first case 71 to which the second case 73 is attached (coil attachment step).

[0077] Alternatively, the coil 74 and the substrate 75a may be provided separately, and the substrate 75a (power supply unit 75) may be connected to the coil 74 attached to the rod support member 50 after the coil mounting process.

[0078] The buffer 10 described above is summarized below.

[0079] Refer to Figure 1. Firstly, the shock absorber 10 includes a substantially cylindrical cylinder 40 filled with oil, a rod support member 50 provided so as to be displaceable relative to the cylinder 40, a piston rod 60 supported by the rod support member 50 and with its tip inserted into the inside of the cylinder 40, and a coil spring 15 that biases the piston rod 60 in the direction of retraction from the cylinder 40.

[0080] Refer to Figure 5. The shock absorber 10 further includes an actuator 70 provided on the rod support member 50, which has a pin 72b that acts linearly in a direction different from the axis CL1 of the cylinder 40. The actuator 70 includes a first case 71 fixed to the rod support member 50 and sealing oil, a second case 73 detachably provided on the first case 71 so as to extend the first case 71, and a coil 74 housed in the first case 71. The length L1 from the bottom of the rod support member 50 to the tip of the first case 71 is shorter than the inner diameter D1 of the coil spring 15.

[0081] Refer to Figure 7. This allows the temporary assembly 10A to be assembled and the coil spring 15 (see Figure 5) to be installed from the outer circumference of the rod support member 50 toward the cylinder 40 while the oil remains sealed. This provides a shock absorber 10 that is easy to assemble.

[0082] Refer to Figure 3. Secondly, the first buffer 10 is formed of a magnetic material, with the first case 71 and the second case 73 forming a magnetic path. This ensures ease of assembly while providing sufficient driving force to the pin 72b.

[0083] Thirdly, in the second buffer 10, the second case 73 is cylindrical, and the inner diameter of the second case 73 is larger than the outer diameter of the coil 74. The coil 74 can be installed after the second case 73 has been installed. This increases the degree of freedom in assembly and is preferable.

[0084] Fourth, in either the second or third buffer 10, the inner circumferential surface of the first case 71 faces the outer circumferential surface of the coil 74. By positioning the first case 71 close to the coil 74, the first case 71 can be used more reliably as a magnetic path.

[0085] Fifth, in any of the second to fourth buffers 10, the tip of the second case 73 overlaps the outer surface of the first case 71. By overlapping a portion of them, the function as a magnetic path can be performed more reliably.

[0086] Sixth, in any of the first to fifth buffers 10, a first case seal member 71c is provided between the rod support member 50 and the first case 71 to seal the space between them. This makes it possible to more reliably suppress the leakage of oil filled in the rod support member 50 to the actuator 70 side.

[0087] Seventh, in any of the first to sixth shock absorbers 10, the pin 72b is displaced in a direction substantially perpendicular to the axis CL1 of the cylinder 40. The shock absorber 10 can be made compact with reference to the direction along the axis CL1 of the cylinder 40.

[0088] Refer to Figures 7 and 8. Eighth, the method for manufacturing the shock absorber 10 includes a preparation step of preparing a cylinder 40, a piston rod 60, a coil spring 15, a rod support member 50, a first case 71, a second case 73, and a coil 74; a temporary assembly step of inserting the tip of the piston rod 60 into the inside of the cylinder 40, supporting the other end of the piston rod 60 with the rod support member 50, attaching the first case 71 to the rod support member 50, and obtaining a temporary assembly 10A; a coil spring attachment step of providing the coil spring 15 along the outer circumference of the temporary assembly 10A from the rod support member 50 toward the cylinder 40; a second case attachment step of attaching the second case 73 to the first case 71 while the coil spring 15 is attached to the outer circumference of the cylinder 40; and a coil attachment step of attaching the coil 74 to the first case 71 to which the second case 73 is attached.

[0089] The temporary assembly 10A can be assembled, and the coil spring 15 (see Figure 5) can be installed from the outer circumference of the rod support member 50 toward the cylinder 40 while the oil is still sealed. This provides a shock absorber 10 that is easy to assemble.

[0090] Ninthly, in the eighth method for manufacturing a shock absorber, in the preparation step, the substrate 75a is connected to the coil 74. The coil mounting step can be easily performed.

[0091] Furthermore, the present invention is not limited to the examples provided, provided that it achieves the functions and effects of the present invention.

[0092] The shock absorber of the present invention is suitable for use as a rear cushion in a saddle-type vehicle.

[0093] 10... Shock absorber 15... Coil spring 40... Cylinder 50... Rod support member 60... Piston rod 70... Actuator 71... First case, 71c... First case seal member 72b... Pin 73... Second case 74... Coil 75a... Circuit board 10A... Temporary assembly L1... Length from the case of the first case to the rod support member D1... Inner diameter of the coil spring CL1... Axis of the cylinder

Claims

1. A shock absorber comprising: a substantially cylindrical cylinder filled with oil; a rod support member provided to be displaceable relative to the cylinder; a piston rod supported by the rod support member and having its tip inserted into the cylinder; a coil spring biasing the piston rod toward the direction toward the retraction of the cylinder; and an actuator provided on the rod support member and having a pin that acts linearly toward a direction different from the axis of the cylinder, wherein the actuator comprises: a first case fixed to the rod support member and sealing the oil; a second case detachably provided on the first case so as to extend the first case; and a coil housed in the first case, wherein the length from the bottom of the rod support member to the tip of the first case is shorter than the inner diameter of the coil spring.

2. The buffer according to claim 1, wherein the first case and the second case are formed of a magnetic material, and a magnetic path is formed by the first case and the second case.

3. The buffer according to claim 2, wherein the second case is cylindrical, and the inner diameter of the second case is larger than the outer diameter of the coil.

4. The buffer according to claim 2, wherein the inner circumferential surface of the first case faces the outer circumferential surface of the coil.

5. The buffer according to claim 2, wherein the tip of the second case overlaps the outer circumferential surface of the first case.

6. The shock absorber according to claim 1, wherein a first case sealing member is provided between the rod support member and the first case to seal the space between them.

7. The shock absorber according to claim 1, wherein the pin is displaced in a direction substantially perpendicular to the axis of the cylinder.

8. A method for manufacturing a shock absorber, comprising: a preparation step of preparing a cylinder, a rod support member, a piston rod, a coil spring, a first case, a second case, and a coil; a temporary assembly step of inserting the tip of the piston rod into the inside of the cylinder, supporting the other end of the piston rod with the rod support member, attaching the first case to the rod support member, and obtaining a temporary assembly; a coil spring attachment step of providing the coil spring along the outer circumference of the temporary assembly from the rod support member toward the cylinder; a second case attachment step of attaching the second case to the first case while the coil spring is attached to the outer circumference of the cylinder; and a coil attachment step of attaching the coil to the first case to which the second case is attached.

9. The method for manufacturing a buffer according to claim 8, wherein a substrate is connected to the coil in the preparation step.

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