WO2023181351A1

WO2023181351A1 - Rear cushion unit

Info

Publication number: WO2023181351A1
Application number: PCT/JP2022/014399
Authority: WO
Inventors: 政信秋本
Original assignee: Ｋｙｂモーターサイクルサスペンション株式会社
Priority date: 2022-03-25
Filing date: 2022-03-25
Publication date: 2023-09-28
Also published as: TWI839029B; JP7356623B1; TW202338227A; JPWO2023181351A1

Abstract

This rear cushion unit (RCU) is interposed between a vehicle body (F) and a rear wheel (W) of a saddled vehicle (M), and comprises: a cylinder (1); a piston (2) which is movably inserted into the cylinder (1) and divides the inside of the cylinder (1) into an expansion-side chamber (R1) and a pressure-side chamber (R2) which are filled with a liquid; a piston rod (3) which is movably inserted into the cylinder (1) and is connected to the piston (2); a tank (4) for accommodating the liquid; a first passage (P1) and a second passage (P2) which connect the expansion-side chamber (R1) and the pressure-side chamber (R2) in parallel to each other; a third passage (P3) which connects the pressure-side chamber (R2) and the tank (4); an expansion-side damping force adjusting passage (P4) which is provided outside the cylinder (1) and connects the expansion-side chamber (R1) and the pressure-side chamber (R2); an expansion-side damping valve (5) which is provided to the first passage (P1) and applies resistance to flow of the liquid from the expansion-side chamber (R1) to the pressure-side chamber (R2); a pressure-side check valve (6) which is provided to the second passage (P2) and allows only the flow of the liquid from the pressure-side chamber (R2) to the expansion-side chamber (R1); and an expansion-side damping force adjusting valve (EV) which is provided to the expansion-side damping force adjusting passage (P4) and can change the flow passage area in response to an operation from the outside.

Description

rear cushion unit

The present invention relates to a rear cushion unit.

A shock absorber is used, for example, by being interposed between the vehicle body and wheels of a straddle-type vehicle, and suppresses vibrations of the vehicle body and wheels using damping force generated during expansion and contraction.

Such a shock absorber includes, for example, a cylinder, a piston that is movably inserted into the cylinder and divides the cylinder into a compression side chamber and a compression side chamber filled with hydraulic oil, and a piston that is movably inserted into the cylinder and divides the cylinder into a compression side chamber and a compression side chamber filled with hydraulic oil. A piston rod is connected to the piston, a pressure side check valve is provided on the piston and allows only the flow of hydraulic oil from the compression side chamber to the rebound side chamber, and a pressure side check valve is provided on the outer circumferential side of the cylinder and extends between the cylinder and the piston rod. A cylindrical body that forms an expansion side passage that communicates the side chamber and the compression side chamber, an outer tube that is provided on the outer periphery of the cylindrical body and forms a tank that stores hydraulic oil between the cylindrical body, the cylinder, the cylindrical body, and A bracket that closes the lower end of the outer tube, a rebound damping valve that is attached to the bracket and placed in the middle of the rebound passage, and a pressure side damping valve that is installed on the bracket and provides resistance to the flow of hydraulic oil from the pressure side chamber toward the tank. It includes a damping force adjustment valve and an expansion side check valve that is provided on the bracket and allows only the flow of hydraulic oil from the tank to the pressure side chamber (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2009-019715

In conventional shock absorbers, a large rebound damping valve with a leaf valve is installed on a bracket that closes off the lower end of the cylinder, so the bracket that accommodates the rebound damping valve becomes large and requires less space for installation. It is difficult to use it as a rear cushion unit installed between the body and rear wheels of saddle-type vehicles due to restrictions.

In addition, in conventional shock absorbers, the piston rod is cylindrical, and the inside of the piston rod is used as a passage for adjusting damping force that communicates the expansion side chamber and the compression side chamber, and the needle valve housed in the piston rod is operated. The flow area of the damping force adjustment passage is adjusted by operating from the tip side of the piston rod. Therefore, when trying to use a conventional shock absorber as a rear cushion unit, the operating part of the needle valve is placed at the lower end of the piston rod connected to the axle, making it difficult to operate the needle valve and Adjusting the damping force becomes complicated.

Therefore, an object of the present invention is to provide a rear cushion unit that can be easily mounted on the rear wheel side of a straddle-type vehicle and that can easily adjust the damping force during the extension operation.

The rear cushion unit is interposed between the body and the rear wheels of a saddle-ride type vehicle, and is divided into a cylinder, and a compression side chamber and a compression side chamber that are movably inserted into the cylinder and filled with liquid. a piston rod that is movably inserted into the cylinder and connected to the piston, a tank that stores liquid, and a first passage and a second passage that communicate in parallel with the expansion side chamber and the compression side chamber, respectively. a third passage communicating between the compression side chamber and the tank; a rebound damping force adjustment passage provided outside the cylinder and communicating the expansion side chamber and the compression side chamber; A rebound-side damping valve that provides resistance to the flow of liquid toward the compression-side chamber, a compression-side check valve that is provided in the second passage and allows only the flow of liquid from the compression-side chamber toward the expansion-side chamber, and a rebound-side damping force adjustment passage. A rebound damping force adjustment valve is provided and the flow path area can be changed by operating from the outside.

In a rear cushion unit configured in this way, the piston is equipped with a rebound damping valve, and a rebound damping force adjustment valve that is provided outside the cylinder is capable of changing the flow path area with a compact configuration. Therefore, it is possible to adjust the damping force during the extension operation while avoiding increasing the external size of the rear cushion unit.

The rebound damping force adjustment valve is provided in the rebound damping force adjustment passage provided on the outside of the cylinder, and is connected to the cylinder that is connected to the vehicle body when the rear cushion unit is installed on a saddle type vehicle. installed on the side. In this way, when the rear cushion unit is installed on a saddle-ride type vehicle, the cylinder is placed on the vehicle body side and the piston rod is placed on the rear wheel side, but the rebound damping force adjustment valve is placed on the cylinder side. The user can easily operate the rebound damping force adjustment valve.

FIG. 1 is a longitudinal sectional view of a rear cushion unit in one embodiment. FIG. 2 is a diagram showing a rear cushion unit attached to a straddle-type vehicle. FIG. 3 is a perspective view of a rear cushion unit in one embodiment. FIG. 4 is a plan view of the rear cushion unit in one embodiment. FIG. 5 is an enlarged cross-sectional view of the rebound damping force adjustment valve portion of the rear cushion unit in one embodiment. FIG. 6 is an enlarged sectional view of the valve unit portion of the rear cushion unit in one embodiment. FIG. 7 is an enlarged cross-sectional view of the rebound damping force adjustment valve portion of the rear cushion unit in one embodiment.

The present invention will be described below based on the embodiments shown in the figures. As shown in FIGS. 1 and 2, the rear cushion unit RCU in one embodiment includes a cylinder 1, a compression side chamber R1 that is movably inserted into the cylinder 1, and fills the cylinder 1 with liquid. A piston 2 partitioned into R2, a piston rod 3 movably inserted into the cylinder 1 and connected to the piston 2, a tank 4 for storing liquid, and a expansion side chamber R1 and a compression side chamber R2 are arranged in parallel. A first passage P1 and a second passage P2 that communicate with each other, a third passage P3 that communicates between the compression side chamber R2 and the tank 4, and a third passage P3 that is provided outside the cylinder 1 and communicates between the expansion side chamber R1 and the compression side chamber R2. a rebound damping force adjustment passage P4 that is provided in the first passage P1 and provides resistance to the flow of liquid from the growth side chamber R1 to the compression side chamber R2; A pressure side check valve 6 that only allows liquid to flow from the chamber R2 to the growth side chamber R1, and a growth side damping force adjustment that is provided in the growth side damping force adjustment passage P4 and allows the flow path area to be changed by operation from the outside. It is equipped with a valve EV.

As shown in FIG. 2, this rear cushion unit RCU is used by being interposed between a vehicle body F and a rear wheel W in a straddle-type vehicle M such as a motorcycle. Suppress vibration.

Hereinafter, each part of the rear cushion unit RCU will be explained in detail. As shown in FIG. 1, the rear cushion unit RCU of this embodiment includes an outer cylinder 15 that is disposed on the outer peripheral side of the cylinder 1 and covers the cylinder 1. An annular gap is provided between the cylinder 1 and the outer cylinder 15 to form a rebound damping force adjustment passage P4.

An upper cap 11 is attached to the upper ends of the cylinder 1 and the outer cylinder 15 in FIG. 1, and the openings at the upper ends of the cylinder 1 and the outer cylinder 15 are closed by the upper cap 11.

Furthermore, an annular rod guide 7 is fitted to the lower end of the cylinder 1 in FIG. The rod guide 7 includes an annular main body 7a that fits on the inner periphery of the outer cylinder 15, and a convex portion 7b that protrudes from the upper end of the main body 7a in FIG. 1 and fits on the inner periphery of the cylinder 1. Further, a groove 7c is formed in the rod guide 7 from the outer periphery of the convex portion 7b to the main body 7a. When the rod guide 7 is fitted to the outer cylinder 15 and the cylinder 1, the convex part 7b is fitted to the inner circumference of the cylinder 1, but the inside of the cylinder 1 is exposed to the extension formed between the cylinder 1 and the outer cylinder 15 through the groove 7c. It communicates with the side damping force adjustment passage P4.

Furthermore, an annular seal member 8 and an annular plate 9 are inserted into the inner periphery of the lower end of the outer cylinder 15 in FIG. 1 in a stacked state below the annular rod guide 7. The cylinder 1, rod guide 7, seal member 8, and plate 9 inserted into the outer cylinder 15 are held between the crimped portion 15a formed by crimping the lower end of the outer cylinder 15 and the upper cap 11. , are immovably fixed to the outer cylinder 15. Note that the design of the means for fixing the cylinder 1, rod guide 7, seal member 8, and plate 9 to the outer cylinder 15 can be changed as desired.

Furthermore, a piston rod 3 having a piston 2 attached to its upper end is movably inserted into the cylinder 1. The piston rod 3 is inserted into the cylinder 1 by being slidably inserted through the inner periphery of the seal member 8 and the inner periphery of the rod guide 7, and is guided to move in the axial direction by the rod guide 7. The seal member 8 is in sliding contact with the outer periphery of the piston rod 3 to seal the outer periphery of the piston rod 3 and thereby hermetically seal the inside of the cylinder 1 .

The inside of the cylinder 1 is divided by the piston 2 into a growth side chamber R1 and a compression side chamber R2 filled with liquid. Therefore, the growth side damping force adjustment passage P4 is communicated with the growth side chamber R1 through the groove 7c of the rod guide 7. Note that in this embodiment, the liquid is hydraulic oil, but other liquids such as water and an aqueous solution can also be used.

A bracket B1 is attached to the lower end of the piston rod 3 in FIG. 1, which can be connected to a swing arm SA that holds a rear wheel W in a saddle-ride type vehicle M, and a cylinder is attached to the outer periphery of the piston rod 3 near the lower end in FIG. A shaped bump cushion 14 is attached.

When the bump cushion 14 is compressed by coming into contact with the plate 9 fixed to the inner periphery of the lower end of the outer cylinder 15 when the rear cushion unit RCU is most compressed, it exerts an elastic force and the bump cushion 14 is compressed to the maximum of the rear cushion unit RCU. Alleviates the shock during contraction.

The piston 2 is provided with a first passage P1 and a second passage P2 that connect the expansion side chamber R1 and the compression side chamber R2 in parallel, respectively. Further, the piston 2 includes a rebound damping valve 5 that can open and close the first passage P1 and provides resistance to the flow of liquid from the growth side chamber R1 to the compression side chamber R2, and a second passage P2 that can open and close the second passage P2. A pressure side check valve 6 is provided that allows only the flow of liquid from the compression side chamber R2 toward the expansion side chamber R1.

The rebound-side damping valve 5 is a valve that can exert a damping force that provides resistance to the flow of hydraulic oil from the rebound-side chamber R1 toward the compression-side chamber R2 and prevents the rear cushion unit RCU from extending when the rear cushion unit RCU is extended. good. Specifically, the growth side damping valve 5 is constructed by laminating a plurality of annular plates on the upper end of the piston 2 in FIG. 1, and opens the first passage P1 when bent by the pressure of the growth side chamber R1. It may be a laminated leaf valve or the like.

Further, the compression side check valve 6 may be any valve that can only allow the flow of hydraulic oil from the compression side chamber R2 toward the expansion side chamber R1 without providing any significant resistance during the contraction operation of the rear cushion unit RCU. Specifically, the pressure side check valve 6 is composed of, for example, an annular plate stacked on the lower end of the piston 2 in FIG. 1, and a spring with a small spring constant that presses the annular plate. It may be a valve or the like that opens the two passages P2.

In this embodiment, the upper cap 11 includes a cap part 11a attached to the upper end of the cylinder 1 in FIG. 1, a tank holding part 11b holding the tank 4, and a tank holding part extending from the side of the cap part 11a. 11b, and a cylindrical first valve case forming a first valve hole h1 provided in the cap part 11a and accommodating the rebound damping force adjustment valve EV. 11d, and a cylindrical second valve case 11e forming a second valve hole h2 for accommodating the valve unit V provided in the middle of the third passage P3.

The cap portion 11a fits into the upper end of the cylinder 1 in FIG. 3 and is screwed to the outer periphery of the outer cylinder 15 to close the upper ends of the cylinder 1 and the outer cylinder 15, and is attached to the upper end of the cylinder 1 in FIG. A bracket B2 connectable to the vehicle body F at M is provided. Further, the connecting portion 11c protrudes from the side of the cap portion 11a, curves downward in FIG. 3, and is connected to the socket-shaped tank holding portion 11b. Note that a cylindrical spring receiver 16 is fitted between the cap portion 11a of the upper cap 11 and the outer periphery of the outer cylinder 15. A suspension spring S made of a coil spring is interposed between the spring receiver 16 and the bracket B1 at the lower end of the piston rod 3. The suspension spring S always biases the piston rod 3 in the direction of protruding from the cylinder 1, that is, in the direction of extending the rear cushion unit RCU, and connects the rear cushion unit RCU with the body F of the saddle type vehicle M. When interposed between the wheel W and the wheel W, the vehicle body F is supported elastically.

The tank holding part 11b has a capped cylindrical shape, the upper end is integrally connected to the lower end of the connecting part 11c, and the lower end is provided with a screw part 11b1 on the outer periphery. A cylindrical tank 4 is screwed onto a threaded portion 11b1 on the outer periphery of the lower end of the tank holding portion 11b.

In this embodiment, the tank 4 has a cylindrical shape and is screwed onto the tank holding part 11b. A diaphragm 12 is slidably inserted into the tank 4, and the inside of the tank 4 is divided by the diaphragm 12 into a liquid chamber L filled with liquid and an air chamber G filled with gas. There is. The air chamber G is filled with gas so that at least the pressure within the air chamber G is equal to or higher than atmospheric pressure when the rear cushion unit RCU is fully extended. Note that the liquid chamber L and the air chamber G in the tank 4 may be partitioned by using a free piston, a bladder, or the like instead of using the diaphragm 12.

The liquid chamber L in the tank 4 is communicated with the inside of the second valve case 11e via a port 11c1 provided inside the connecting portion 11c. Further, the inside of the second valve case 11e is communicated with the pressure side chamber R2 via a port 11a2 provided in the cap portion 11a. Therefore, the liquid chamber L is communicated with the pressure side chamber R2 via the port 11c1, the inside of the second valve case 11e, and the port 11a2.

The first valve case 11d and the second valve case 11e are provided on the sides of the cap portion 11a and on both sides of the connecting portion 11c with the connecting portion 11c in between. Specifically, as shown in FIG. 4, the first valve case 11d has a cylindrical shape, is disposed on the right side of the connecting portion 11c with respect to the cap portion 11a, and has its own axis L1 aligned with the axis of the cylinder 1. It is provided so as to be orthogonal to the LC. The second valve case 11e has a cylindrical shape and is disposed on the left side of the connecting portion 11c with respect to the cap portion 11a so that its axis L2 is orthogonal to the axis LC of the cylinder 1. . Note that the attachment positions of the first valve case 11d and the second valve case 11e to the cap portion 11a are not limited to the above-mentioned positions, and the design can be changed.

The first valve case 11d forms a first valve hole h1, and the second valve case 11e forms a second valve hole h2. In the rear cushion unit RCU of the present embodiment, the axis L1 of the first valve case 11d and the axis L2 of the second valve case 11e are orthogonal to the axis LC of the cylinder 1, so that the first valve hole h1 and The second valve holes h2 are arranged radially around the axis LC of the cylinder 1 with the connecting portion 11c in between.

Further, the cap portion 11a is provided with a port 11a1 that opens at the bottom of the first valve hole h1 and communicates with the pressure side chamber R2 in the cylinder 1. Furthermore, the side portion of the first valve hole h1 communicates with the growth side chamber R1 through the growth side damping force adjustment passage P4 between the cylinder 1 and the outer cylinder 15. Therefore, the growth side chamber R1 and the compression side chamber R2 are communicated by the growth side damping force adjustment passage P4 and the first valve hole h1, bypassing the first passage P1 and the second passage P2 provided in the piston 2. .

As described above, the cap portion 11a is provided with a port 11a2 that opens at the bottom of the second valve hole h2 and communicates with the pressure side chamber R2 in the cylinder 1. Furthermore, the side part of the second valve hole h2 is communicated with the tank 4 held by the tank holding part 11b through a port 11c1 formed in the connecting part 11c. In this way, in the rear cushion unit RCU of the present embodiment, the upper cap 11 has the third passage P3 formed by the port 11a2, the port 11c1, and the second valve hole h2, and which communicates the pressure side chamber R2 and the tank 4. It is equipped with

The upper cap 11 connects the cylinder 1 and the tank 4, and has a first valve hole h1 in which the rebound damping force adjustment valve EV is accommodated, and a second valve hole h1 in which the valve unit V is accommodated in the middle of the third passage P3. and a valve hole h2. The upper cap 11 includes a first valve case 11d forming a first valve hole h1 and a second valve case 11e forming a second valve hole h2 on the side of the cap part 11a that closes the upper end of the cylinder 1. A tank holding part 11b to which the tank 4 is attached is provided below the connecting part 11c. Therefore, by arranging the rebound damping force adjustment valve EV and the valve unit V on the side of the cylinder 1, it is possible to suppress the overall length of the rear cushion unit RCU from increasing. Note that the first valve hole h1 and the second valve hole h2 are formed by a first valve case 11d and a second valve case 11e that are arranged along the radial direction with respect to the cylinder 1, and their opening ends are opposite to the cylinder. Since it faces to the side, the rebound damping force adjustment valve EV and the valve unit V can be easily attached and detached from the side of the rear cushion unit RCU.

As shown in FIG. 5, a threaded portion 11d1 is formed on the inner periphery of the open end of the first valve case 11d, and a plurality of grooves 11d2 are formed in the axial direction inside the threaded portion 11d1 in the circumferential direction. They are provided along the axial direction at equal intervals.

The expansion side damping force adjustment valve EV is accommodated in the first valve hole h1 formed by the first valve case 11d. The expansion side damping force adjustment valve EV is screwed to an annular valve seat 50, a valve body 51 which is shaft-shaped and has a valve head 51b at its tip that can be moved toward and away from the annular valve seat 50, and a threaded portion 11d1. It includes a cylindrical case 52 in which the valve body 51 is attached to the first valve case 11d. The valve body 51 is housed in the first valve case 11d so as to be movable in the axial direction.

The annular valve seat 50 is formed around the port 11a1 of the cap portion 11a that forms the bottom of the first valve hole h1. As shown in FIG. 5, the valve body 51 includes a cylindrical body 51a, a valve head 51b protruding in the axial direction from the tip of the body 51a, and a body 51a extending in the axial direction from the rear end of the body 51a. A small diameter portion 51c having a smaller outer diameter is provided.

The body portion 51a is attached to a screw portion 51a1 provided on the outer periphery, a through hole 51a2 that penetrates the body portion 51a in the radial direction, and an annular groove 51a3 provided on the outer periphery on the distal end side of the through hole 51a2. and a seal ring 51a4. When the valve body 51 is inserted into the first valve hole h1 formed in the first valve case 11d, the body portion 51a fits into the inner circumference of the first valve case 11d, and the seal ring 51a4 fits into the first valve case 11d. The first valve hole h1 is sealed by slidingly contacting the inner periphery of the first valve hole h1. Moreover, even if the valve body 51 moves in the axial direction into the first valve case 11d, the body portion 51a is located closer to the atmosphere than the opening of the expansion side damping force adjustment passage P4 with respect to the first valve hole h1. It is always placed on the middle left side and does not block the opening.

The valve head 51b includes a cylindrical shaft portion 51b1 extending in the axial direction from the body portion 51a, and a conical shaft portion 51b1 that is provided at the tip of the shaft portion 51b1 and can enter the inner circumference of the annular valve seat 50, that is, the port 11a1. The needle 51b2 is provided. The shape of the needle 51b2 may be a shape other than a conical shape as long as the tip thereof is tapered and the flow path area can be adjusted by movement in the axial direction with respect to the annular valve seat 50.

The outer diameter of the shaft portion 51b1 is larger than the diameter of the port 11a1, and the outer circumference of the end surface of the shaft portion 51b1 faces the annular valve seat 50 in the axial direction, and the outer diameter of the base end of the needle 51b2 is larger than that of the port 11a1. has a larger diameter than the diameter of the port 11a1. Therefore, when the valve body 51 is moved in the direction of penetrating the deepest part into the first valve case 11d, the side surface of the needle 51b2 is seated on the inner edge of the annular valve seat 50, thereby blocking the port 11a1. Further, when the side surface of the needle 51b2 is separated from the annular valve seat 50, a gap is created between the needle 51b2 and the inner edge of the annular valve seat 50, and the port 11a1 is opened, and as the valve body 51 moves in the axial direction, By increasing or decreasing the gap, the resistance given to the flow of liquid passing through the port 11a1 can be adjusted in magnitude. Note that the outer diameter of the proximal end of the needle 51b2 may be made smaller than the diameter of the port 11a1, and the right end of the shaft portion 51b1 may be brought into contact with the annular valve seat 50 to block the port 11a1. Further, the small diameter portion 51c extends in the axial direction from the rear end of the body portion 51a, and is provided with a groove 51c1 at the rear end to enable operation from the outside.

The case 52 is cylindrical and has a small inner diameter on the atmosphere side, and can be provided with a stepped portion 52a on the inner periphery, and a threaded portion 52b on the outer periphery and on the side opposite to the atmosphere of the stepped portion 52a on the inner periphery. It is provided with a threaded portion 52c.

The valve body 51 is inserted into the case 52, and the threaded portion 51a1 of the body portion 51a is screwed into the threaded portion 52c on the inner periphery of the case 52. The outer diameter of the small diameter portion 51c is set to be a diameter that can fit into the inner diameter of the case 52 on the atmospheric side, and the seal ring 51c2 attached to the outer periphery of the small diameter portion 51c is in close contact with the inner periphery of the case 52 to close the valve body. 51 and the case 52 are sealed.

Then, the case 52 with the valve body 51 screwed onto the inner circumferential side is inserted into the first valve case 11d, and the outer circumferential threaded portion 52b is screwed into the threaded portion 11d1 to form the first valve case 11d. Fixed. When the valve body 51 and the case 52 are attached to the first valve case 11d in this way, the valve body 51 and the case 52 form a feed screw mechanism, so that the user can insert a tool such as a screwdriver into the groove of the small diameter portion 51c. 51c1 and rotates the valve body 51, the valve body 51 moves in the axial direction within the first valve hole h1. Since the valve body 51 is movable in the axial direction within the first valve hole h1 in this way, the valve head 51b can move closer and closer to the annular valve seat 50 to open and close the port 11a1, and the needle 51b2 and the annular valve seat By adjusting the gap between the port 50 and the port 11a1, the resistance given to the flow of liquid passing through the port 11a1 can be adjusted.

Note that two balls 53 and 54 and a spring 55 disposed between the balls 53 and 54 are inserted into a through hole 51a2 provided in the body 51a of the valve body 51, and the valve body 51 is inserted into the through hole 51a2. When inserted into the first valve case 11d, the through hole 51a2 faces the groove 11d2 formed on the inner circumference of the first valve case 11d. The balls 53, 54 are urged by a spring 55 in a direction to protrude outward from the through hole 51a2, and the first valve case 11d, the balls 53, 54, and the spring 55 form a detent mechanism. Therefore, when the balls 53 and 54 enter the groove 11d2 facing each other, rotation of the valve body 51 in the circumferential direction with respect to the first valve case 11d can be restricted as long as the valve body 51 is not rotated with a torque greater than the detent torque. Since the positional relationship between the valve body 51 and the annular valve seat 50 is maintained by the detent mechanism in this way, the flow path area of the rebound damping force adjustment valve EV can be prevented from changing arbitrarily while the straddle-type vehicle M is running. can be prevented.

As shown in FIGS. 1 and 7, in the rebound damping force adjustment valve EV configured in this way, the valve head 51b is located between the cylinder 1 and the outer cylinder 15 when viewed from the axial direction. located in the range between. Therefore, the rebound damping force adjustment valve EV can be arranged as close as possible to the axis LC of the cylinder 1 while being located close to the ends of the cylinder 1 and the outer cylinder 15. Even if the rear cushion unit RCU is provided, the overall length of the rear cushion unit RCU does not increase and the size of the rear cushion unit RCU does not increase in the radial direction.

In the rear cushion unit RCU of this embodiment, the valve unit V provided in the middle of the third passage P3 is accommodated in the second valve hole h2 formed by the second valve case 11e. The valve unit V is removably housed in a second valve case 11e that forms a second valve hole h2 of the upper cap 11.

As shown in FIG. 6, the valve unit V includes a pressure side damping passage PV1, a pressure side relief passage PV2, a suction passage PV3, a compression side damping force adjustment passage PV4, and a pressure side damping passage PV1, which are connected in parallel in the middle of the third passage P3. A pressure side damping valve V1 is provided in the pressure side relief passage PV2 and is arranged in parallel with the pressure side damping valve V1 to provide resistance to the flow of liquid from the pressure side chamber R2 toward the tank 4. a pressure side relief valve that opens when the pressure difference between the pressure in the pressure side chamber R2 and the pressure in the tank 4 reaches a valve opening pressure, and allows liquid to flow from the pressure side chamber R2 toward the tank 4; V2, an expansion side check valve V3 provided in the suction passage PV3 and arranged in parallel with the pressure side damping valve V1 to allow only the flow of liquid from the tank 4 toward the pressure side chamber R2, and an expansion side check valve V3 provided in the pressure side damping force adjustment passage PV4. The needle valve V4 is arranged in parallel with the pressure side damping valve V1 to provide resistance to the flow of liquid passing between the tank 4 and the pressure side chamber R2, and the resistance can be adjusted by external operation.

Specifically, the valve unit V includes a cylindrical valve holding shaft 21 inserted into the second valve hole h2 in the upper cap 11, a needle 22 inserted into the valve holding shaft 21, and a valve holding shaft 21. a collar 24 attached to the outer periphery of the valve holding shaft 21; an annular spacer 25 fitted to the outer periphery of the collar 24 so as to be movable in the axial direction; an annular plate 26; The plate 27, a disc spring 28 which is also arranged on the outer periphery of the collar 24 and urges the spacer 25, the annular plate 26, and the annular plate 27 toward the valve disk 23, hold the valve disk 23 and the collar 24 together. It includes a nut 29 fixed to the shaft 21, a valve body 30 and a spring 31 housed in the needle 22, and a cylindrical case 32 attached to the inner periphery of the proximal opening of the valve holding shaft 21. .

As shown in FIG. 6, the valve holding shaft 21 has a cylindrical shape, and has a large diameter portion 21a having the largest inner and outer diameters at the base end, a small diameter portion 21b having the smallest inner and outer diameters at the tip, the large diameter portion 21a, and the small diameter portion. 21b is provided with a medium diameter portion 21c whose inner and outer diameters are intermediate between the large diameter portion 21a and the small diameter portion 21b. Further, the valve holding shaft 21 includes a flange 21d provided on the outer periphery of the large diameter portion 21a and in the middle in the axial direction, and a hole 21e that communicates between the inside and outside of the medium diameter portion 21c.

Further, the valve holding shaft 21 is provided with an annular groove 21f and a threaded portion 21g on the outer periphery of the large diameter portion 21a and on the distal end side of the flange 21d. The upper cap 11 is fixed to the upper cap 11 by being screwed to a threaded portion 11e1 on the inner periphery of the opening end. The outer circumferential shape of the large diameter portion 21a on the proximal end side of the flange 21d has a hexagonal shape that enables gripping of a tool, and the valve holding shaft 21 can be easily screwed into the second valve case 11e by using the tool. Can be combined.

Further, a seal ring 21i is attached to the outer periphery of the annular groove 21f of the large diameter portion 21a, and when the valve holding shaft 21 is inserted into the second valve case 11e, the seal ring 21i is attached to the inside of the second valve case 11e. A seal is formed between the valve holding shaft 21 and the second valve case 11e by closely contacting the periphery thereof. A valve disc 23 that fits on the inner periphery of the second valve case 11e is attached to the outer periphery of the small diameter portion 21b of the valve holding shaft 21, and the flange 21d of the valve holding shaft 21 is attached to the end surface of the second valve case 11e. When inserted into the second valve hole h2 formed by the second valve case 11e of the upper cap 11 until they abut, the inside of the second valve hole h2 becomes a chamber A communicating with the pressure side chamber R2 via the port 11a2 by the valve disc 23. , and a chamber B that communicates with the tank 4 via the port 11c1. The inside of the valve holding shaft 21 is communicated with the pressure side chamber R2 via the chamber A in the second valve hole h2 and the port 11a2, and is provided in the hole 21e, the chamber B in the second valve hole h2, and the connecting part 11c. The liquid chamber L in the tank 4 is communicated with the liquid chamber L through the port 11c1.

Further, the inner periphery of the large diameter portion 21a of the valve holding shaft 21 is reduced in diameter at the tip end, and a threaded portion 21h is provided on the reduced diameter inner periphery. A stepped portion is formed on the inner peripheral side of the valve holding shaft 21 at the boundary between the medium diameter portion 21c and the small diameter portion 21b. In this way, the stepped portion formed on the inner periphery of the valve holding shaft 21 forms the annular valve seat 33 in the needle valve V4.

The needle 22 includes a head 22a and an operating barrel 22b connected to the head 22a, and is inserted into the valve holding shaft 21 so as to be movable in the axial direction in the left-right direction in FIG.

The head 22a has a cylindrical shape, and includes a needle portion 22a1 that is provided on the outer periphery of the tip at the right end in FIG. The flange 22a2 is provided with a flange 22a2 that can be moved to and from the seat. The needle portion 22a1 has a shape that becomes tapered toward the tip, and can be inserted into the small diameter portion 21b of the valve holding shaft 21. Further, the outer diameter of the proximal end of the needle portion 22a1 is slightly smaller than the inner diameter of the annular valve seat 33, and when the needle 22 moves in the axial direction within the valve holding shaft 21, the needle portion 22a1 and the annular valve The size of the flow path area formed by the gap between the inner edge of the seat 33 and the inner edge of the seat 33 can be adjusted. In this way, the needle 22 and the annular valve seat 33 form a needle valve V4 within the valve holding shaft 21 that communicates the pressure side chamber R2 and the tank 4. By adjusting the axial position with respect to 21, the flow area of the compression side damping force adjustment passage PV4 formed within the valve holding shaft 21 can be adjusted in size. The shape of the needle portion 22a1 may be a shape other than a conical shape as long as the tip is tapered and the flow path area can be adjusted by movement in the axial direction with respect to the annular valve seat 33. .

Further, the flange 22a2 faces the annular valve seat 33 in the axial direction, and when the needle 22 moves to the right side in FIG. Communication between the inside of the small diameter portion 21b and the inside of the medium diameter portion 21c of the valve holding shaft 21 can be cut off. On the contrary, when the flange 22a2 is spaced apart from the annular valve seat 33, the inside of the small diameter part 21b and the inside of the medium diameter part 21c of the valve holding shaft 21 communicate with each other.

The operating tube 22b has a cylindrical shape with a bottom and includes a cylindrical portion 22b1 and a bottom portion 22b2 having a larger outer diameter than the cylindrical portion 22b1. groove 22b3, and a through hole 22b4 that is formed in the side of the cylindrical portion 22b1 and communicates between the inside and outside of the cylindrical portion 22b1. A rear end 22a3 of the head 22a on the rear side than the flange 22a2 is press-fitted into the cylindrical portion 22b1 of the operating barrel 22b, so that the operating barrel 22b and the head 22a are integrally connected.

The bottom portion 22b2 of the operating barrel 22b has a blind hole 22b5 that opens from the side, and a threaded portion 21h formed on the inner periphery of the large diameter portion 21a of the valve holding shaft 21 on the outer periphery and on the distal end side of the blind hole 22b5. A screw portion 22b6 for screwing is provided. Further, a seal ring 22b7 is attached to the outer periphery of the cylinder portion 22b1 of the operation cylinder 22b.

Then, the needle 22 is inserted into the valve holding shaft 21 and is attached to the valve holding shaft 21 by screwing the threaded portion 22b6 into the threaded portion 21h. When the needle 22 is inserted into the valve holding shaft 21, the seal ring 22b7 comes into sliding contact with the inner periphery of the middle diameter portion 21c of the valve holding shaft 21, and the space between the needle 22 and the valve holding shaft 21 is sealed.

Further, since the threaded part 22b6 of the needle 22 is screwed into the threaded part 21h, when a tool such as a screwdriver (not shown) is inserted into the groove 22b3 at the rear end of the operating barrel 22b and the needle 22 is rotated, the needle 22 is rotated. , moves within the valve holding shaft 21 in the axial direction that is the left-right direction in FIG.

When the needle 22 is accommodated in the valve holding shaft 21 as described above, an annular gap is formed between the outer circumference of the bottom portion 22b2 of the operating barrel 22b of the needle 22 and the inner circumference of the large diameter portion 21a of the valve holding shaft 21. Ru. After inserting the needle 22 into the valve holding shaft 21, when the case 32 is press-fitted into the inner circumference of the large diameter portion 21a of the valve holding shaft 21, the bottom 22b2 of the operation tube 22b and the large diameter portion 21a of the valve holding shaft 21 are connected to each other. The gap between the two is closed. The case 32 is cylindrical and allows the rear end of the bottom 22b2 of the operating barrel 22b to be inserted through the case 32, so that it does not interfere with insertion of the screwdriver into the groove 22b3 in the operating barrel 22b, and the needle relative to the valve holding shaft 21 does not get in the way. 22 is also allowed to move in the axial direction.

The case 32 is provided with grooves 32a along the axial direction at equal intervals in the circumferential direction on the right end side in FIG. 6, which is the tip side of the inner circumference. When the case 32 is press-fitted into the large diameter portion 21a of the valve holding shaft 21 and fixed, the groove 32a faces the blind hole 22b5 of the operation tube 22b. A ball 34 and a spring 35 that biases the ball 34 in a direction to push the ball 34 out of the blind hole 22b5 are inserted into the blind hole 22b5. The case 32, the ball 34, and the spring 35 form a detent mechanism, and when the ball 34 enters the groove 32a oppositely, the valve holding shaft 21 of the needle 22 is rotated as long as the needle 22 is not rotated with a torque greater than the detent torque. rotation in the circumferential direction can be restricted. Since the positional relationship between the needle 22 and the annular valve seat 33 is maintained by the detent mechanism in this way, it is possible to prevent the flow path area of the needle valve V4 from changing arbitrarily while the straddle-type vehicle M is running.

Further, a valve body 30 and a spring 31 are housed within the needle 22. Specifically, the valve body 30 is a spherical body, and the annular rear end of the head 22a of the needle 22 serves as a relief valve valve seat 36, and the valve body 30 is relieved by moving in the axial direction within the cylindrical portion 22b1 of the operation cylinder 22b. The valve seat 36 can be moved into and out of the valve seat 36. Further, a spring 31 made of a coil spring is interposed between the valve body 30 and the bottom portion 22b2 of the operating cylinder 22b, and biases the valve body 30 toward the relief valve valve seat 36.

The diameter of the valve body 30 is larger than the inner peripheral diameter of the rear end of the head 22a, and when seated on the relief valve seat 36, it cuts off communication between the inside of the needle part 22a1 and the inside of the operation cylinder 22b. When separated from the relief valve seat 36, the inside of the needle portion 22a1 and the inside of the operating cylinder 22b are communicated with each other.

Since the cylindrical portion 22b1 of the operating barrel 22b of the needle 22 is provided with a through hole 22b4, the inside of the operating barrel 22b communicates with the inside of the medium diameter portion 21c of the valve holding shaft 21 through the through hole 22b4. The inside of the medium diameter portion 21c of the valve holding shaft 21 is communicated with the tank 4 via the hole 21e and the chamber B, so the inside of the operating cylinder 22b is communicated with the tank 4. Further, the inside of the operation cylinder 22b communicates with the inside of the small diameter portion 21b of the valve holding shaft 21 through the inside of the head 22a of the needle 22. The inside of the small diameter portion 21b of the valve holding shaft 21 is communicated with the pressure side chamber R2 via the chamber A and the port 11a2, so the inside of the operating cylinder 22b is also communicated with the pressure side chamber R2. In this way, the inside of the needle 22 forms a pressure side relief passage PV2 arranged in parallel to the compression side damping force adjustment passage PV4 formed within the valve holding shaft 21, and the valve body 30, A pressure side relief valve V2 composed of a spring 31 and a relief valve seat 36 is provided.

The pressure side relief valve V2 is in a closed state in which the valve body 30 continues to contact the relief valve seat 36 by the spring 31 until the differential pressure between the pressure in the pressure side chamber R2 and the pressure in the tank 4 reaches the valve opening pressure. maintained. In addition, in the pressure side relief valve V2, when the differential pressure between the pressure in the pressure side chamber R2 and the pressure in the tank 4 becomes the valve opening pressure, the valve body 30 is pushed by the pressure in the pressure side chamber R2 and compresses the spring 31. The relief valve is separated from the valve seat 36 to open the pressure side relief passage PV2. The opening pressure at which the pressure side relief valve V2 opens is set to be lower than the maximum pressure that the seal member 8 that seals the outer periphery of the piston rod 3 can withstand.

Note that when the needle valve V4 is abolished, the rear end of the valve holding shaft 21 is closed with a cap instead of the needle 22, and the valve body 30 and the spring 31 disposed between the valve body 30 and the cap are closed. The pressure side relief valve V2 may be constructed by housing it in the valve holding shaft 21 and using the stepped portion between the small diameter portion 21b and the medium diameter portion 21c as a relief valve seat.

On the outer periphery of the small diameter portion 21b of the valve holding shaft 21, a nut is screwed into which the valve disc 23 and the collar 24 are screwed onto the stepped portion on the outer periphery of the small diameter portion 21b and the medium diameter portion 21c and the outer periphery of the tip of the small diameter portion 21b. 29 and fixed. Furthermore, an annular spacer 25 , an annular plate 26 , an annular plate 27 , and an annular disc spring 28 are fitted around the outer periphery of the collar 24 .

The valve disk 23 is annular and has a plurality of ports 23a arranged on the same circumference and passing through the wall thickness of the valve disk 23 in the axial direction, and a plurality of ports 23a provided at the right end in FIG. 6 and communicating with each port 23a. An annular window 23b formed by an annular recess, an annular valve seat 23c that protrudes in the axial direction from the right end in FIG. A seal ring 23e is attached thereto. As described above, when the valve disc 23 is attached to the outer periphery of the small diameter portion 21b of the valve holding shaft 21 and inserted into the second valve hole h2, it fits into the inner periphery of the second valve case 11e and is inserted into the second valve hole h2. The interior of the two-valve hole h2 is divided into a chamber A and a chamber B. A seal ring 23e provided on the outer periphery of the valve disc 23 is in close contact with the inner periphery of the second valve case 11e to seal between the valve disc 23 and the second valve case 11e. This prevents chambers A and B from communicating through the valve case 11e.

The port 23a communicates the chamber A communicating with the pressure side chamber R2 and the chamber B communicating with the tank 4, and functions as the pressure side damping passage PV1 and the suction passage PV3 in the rear cushion unit RCU of this embodiment.

The collar 24 has a cylindrical shape, and includes a fitting cylindrical portion 24a in which a spacer 25, an annular plate 26, an annular plate 27, and an annular disc spring 28 are fitted on the outer periphery, and a fitting cylindrical portion 24a shown in FIG. The fitting cylinder portion 24a has a flange 24b provided at the right end, and is stacked on the valve disk 23 with the left end in FIG. 6 of the fitting cylinder portion 24a in contact with the inner circumference of the right end of the valve disk 23 in FIG.

As described above, the valve disc 23 and the collar 24 are sandwiched between the stepped portion on the outer periphery of the valve holding shaft 21 and the nut 29 in an overlapping state, and are immovably fixed to the valve holding shaft 21.

The spacer 25 is a small-diameter annular plate, and is slidably fitted to the outer periphery of the fitting cylindrical portion 24a of the collar 24, and is movable in the axial direction relative to the valve disc 23. 23 can be viewed from near and far. Note that the outer diameter of the spacer 25 is small so as not to block the port 23a.

The annular plate 26 is an annular plate that is slidably fitted to the outer periphery of the fitting cylindrical portion 24a of the collar 24 and stacked on the spacer 25 on the side opposite to the valve disk. It can move in the axial direction relative to the valve disk 23, and can move near and far from the valve disk 23. Note that the outer diameter of the annular plate 26 is smaller than the inner diameter of the valve seat 23c, and since the annular window 23b is provided in the valve disc 23, deflection toward the outer peripheral side of the valve disc 23 is allowed. .

The annular plate 27 is an annular plate that is slidably fitted to the outer periphery of the fitting cylindrical portion 24a of the collar 24 and stacked on the annular plate 26 on the side opposite to the valve disk. It can move in the axial direction relative to the valve disk 23, and can move near and far from the valve disk 23. The outer diameter of the annular plate 27 is slightly larger than the outer diameter of the valve seat 23c so that it can be moved into and out of the valve seat 23c of the valve disc 23. Further, the annular plate 27 includes a plurality of holes 27a arranged on the same circumference and passing through the annular plate 27 in the axial direction. The diameter of the circumscribed circle of each hole 27a is less than the diameter of the annular plate 26, and when the annular plate 26 is in contact with the annular plate 27, the hole 27a in the annular plate 27 is closed, and the outer circumference of the annular plate 26 is closed. When the valve is bent toward the valve disk 23 and separated from the annular plate 27, the hole 27a is opened. Therefore, when the annular plate 27 is seated on the valve seat 23c with the annular plate 26 in contact with the annular plate 27, the port 23a is closed and the communication between the chambers A and B is cut off. Even when seated on the seat 23c, when the annular plate 26 bends toward the valve disk 23 and separates from the annular plate 27, the hole 27a is opened and the chambers A and B are communicated with each other. Further, when the outer periphery of the annular plate 27 bends toward the side opposite to the valve disk, or when the annular plate 27 moves on the collar 24 in a direction away from the valve disk 23, the port 23a is opened and the chambers A and B are communicated with each other. Ru.

The disc spring 28 is fitted onto the outer periphery of the fitting cylindrical portion 24a of the collar 24, and is interposed between the flange 24b and the annular plate 27 in a state in which initial deflection is applied, and the spacer is always provided. 25, the annular plate 26 and the annular plate 27 are urged toward the valve disk 23 side.

With respect to the flow of liquid passing through the port 23a from the pressure side chamber R2 toward the tank 4, the annular plate 27 is seated on the valve seat 23c under the pressure of the pressure side chamber R2 and the biasing force of the disc spring 28, and the port is closed. However, the annular plate 26 receives the pressure of the pressure side chamber R2 through the hole 27a, bends around the outer edge of the spacer 25 as a fulcrum, and separates from the annular plate 27 to open the port 23a, allowing the tank to flow from the pressure side chamber R2. It allows the liquid to flow towards the 4th direction and provides resistance to this liquid flow. Note that the spacer 25 determines the fulcrum of deflection of the annular plate 26, and by setting the outer diameter of the spacer 25, the amount of resistance that the annular plate 26 gives to the flow of liquid can be adjusted. In this way, the annular plate 26 functions as a valve body in the compression side damping valve V1, the annular plate 27 functions as a valve seat, and the annular plate 26 and the annular plate 27 form the compression side damping valve V1. ing. Note that when the inner periphery of the annular plate 26 is directly supported by the valve disk 23, the spacer 25 may be omitted, or a plurality of annular plates may be stacked to form the valve body of the compression side damping valve V1. Good too.

On the other hand, with respect to the flow of liquid passing through the port 23a from the tank 4 toward the pressure side chamber R2, the annular plate 27 bends under the pressure of the tank 4 and separates from the valve seat 23c, or is moved by a disc spring. 28 is compressed to separate it from the valve disk 23 and open the port 23a, allowing the liquid to flow from the tank 4 toward the pressure side chamber R2 without providing much resistance. In this case, the annular plate 26 receives pressure from the tank 4 side, comes into contact with the annular plate 27, and bends together with the annular plate 27, or moves on the collar 24 and moves away from the valve disk 23. In this way, the annular plate 26 and the annular plate 27 function as a valve body in the expansion side check valve V3, and the valve disc 23 functions as a valve seat in the expansion side check valve V3. 26, annular plate 27, disc spring 28, and collar 24 form an expansion side check valve V3.

Further, in this embodiment, the compression side damping valve V1 and the expansion side check valve V3 are arranged in parallel with the port 23a of the valve disk 23, and the port 23a allows the flow of liquid from the pressure side chamber R2 toward the tank 4. It functions as a pressure side damping passage PV1 and a suction passage PV3 that allows liquid to flow from the tank 4 toward the pressure side chamber R2.

In addition, the valve disk 23 is provided with a port corresponding to the pressure side damping passage PV1, a port corresponding to the suction passage PV3, a pressure side damping valve V1 for opening and closing the port corresponding to the pressure side damping passage PV1, and a port corresponding to the suction passage PV3. You may provide the expansion side check valve V3 which opens and closes the port corresponding to .

Further, the compression side damping valve V1 is configured as described above, and is a valve that can provide resistance to the flow of liquid from the pressure side chamber R2 toward the tank 4 and generate a damping force when the rear cushion unit RCU is contracted. As long as it is sufficient, the design of the valve structure can be changed as appropriate.

Furthermore, although the expansion side check valve V3 is configured as described above, it may be any valve that can only allow the flow of liquid from the tank 4 toward the pressure side chamber R2, so the structure of the valve can be appropriately designed to that extent. Can be changed.

Note that valves having the same configuration as the compression side damping valve V1 and the expansion side check valve V3 may be used as the expansion side damping valve 5 and the compression side check valve 6 in the piston 2.

The specifically configured valve unit V includes a compression side damping passage PV1, a compression side relief passage PV2, a suction passage PV3, and a compression side damping force adjustment passage PV4 that are arranged in parallel with each other, and includes a compression side damping valve V1, a compression side relief valve V2, and a compression side damping force adjustment passage PV4. A check valve V3 and a needle valve V4 are provided in parallel. Therefore, when the valve unit V is inserted into the second valve hole h2 of the upper cap 11, the compression side damping valve V1, the compression side relief valve V2, the rebound side check valve V3, and the needle valve V4 are arranged in parallel with each other in the middle of the third passage P3. It can be installed in

An example of how to assemble the valve unit V configured as described above will be described below. First, the disc spring 28, the annular plate 27, the annular plate 26, and the spacer 25 are fitted to the outer periphery of the fitting cylindrical part 24a of the collar 24 in this order. and assemble. Next, the valve disc 23 and the collar 24, on which the disc spring 28, the annular plate 27, the annular plate 26, and the spacer 25 are assembled, are fitted in order onto the outer periphery of the small diameter portion 21b of the valve holding shaft 21. After attaching, the nut 29 is screwed onto the outer periphery of the tip of the small diameter portion 21b. Then, the valve disk 23 and the collar 24, to which the disc spring 28, the annular plate 27, the annular plate 26, and the spacer 25 are assembled, are fixed to the outer periphery of the small diameter portion 21b of the valve holding shaft 21 by nuts 29.

Next, the spring 31 and the valve body 30 are sequentially inserted into the operating barrel 22b of the needle 22, and the rear end 22a3 of the head 22a is press-fitted into the open end of the operating barrel 22b. and assemble the pressure side relief valve V2 and needle 22. Continuing, after inserting the spring 35 and the ball 34 in order into the blind hole 22b5 opened on the side of the bottom 22b2 of the operation tube 22b of the needle 22, while inserting the needle 22 into the valve holding shaft 21, The threaded portion 22b6 on the outer periphery of the bottom portion 22b2 is screwed into the threaded portion 21h of the valve holding shaft 21.

When the needle 22 is screwed and housed in the valve holding shaft 21, the groove 32a side is inserted into the annular gap between the inner periphery of the large diameter portion 21a of the valve holding shaft 21 and the outer periphery of the operating barrel 22b. 21, and press-fit the case 32 to the inner periphery of the large diameter portion 21a. Then, the case 32 is fixed to the valve holding shaft 21 and prevents the needle 22 from coming off from the valve holding shaft 21.

In this way, when the valve disc 23, collar 24, spacer 25, annular plate 26, annular plate 27, disc spring 28, needle 22 housing the pressure side relief valve V2, and case 32 are assembled to the valve holding shaft 21, Assembly of valve unit V is completed. The completed valve unit V is one unit including a compression side damping valve V1, a compression side relief valve V2, a rebound side check valve V3, and a needle valve V4. Then, the valve unit V is inserted into the second valve case 11e of the upper cap 11, and the threaded part 11e1 is screwed into the threaded part 21g on the outer periphery of the large diameter part 21a of the valve holding shaft 21. It is accommodated in the two valve holes h2 and fixed to the upper cap 11. Since the valve unit V is screwed to the upper cap 11, it can be easily attached to and removed from the upper cap 11. Note that any fastening means other than screw fastening may be used as long as the fastening means allows the valve unit V to be attached to and removed from the upper cap 11.

The rear cushion unit RCU is configured as described above, and its operation will be explained below. In the extension stroke of the rear cushion unit RCU in which the piston 2 moves downward in FIG. The liquid moves to chamber R2. In this extension stroke, the rear cushion unit RCU applies resistance to the flow of liquid passing through the first passage P1 using the extension damping valve 5, and provides resistance to the flow of liquid passing through the extension damping force adjustment passage P4. The side damping force adjustment valve EV provides resistance and generates a damping force on the extension side that prevents extension.

In addition, during the extension stroke of the rear cushion unit RCU, the piston rod 3 withdraws from the cylinder 1, so there is a shortage of liquid in the pressure side chamber R2 by the volume of the piston rod 3 withdrawn from the cylinder 1. The diaphragm 12 expands to expand the air chamber G, and the liquid is supplied from the liquid chamber L of the tank 4 to the pressure side chamber R2 via the expansion side check valve V3. Specifically, the annular plate 27 is separated from the valve seat 23c in response to the pressure of the tank 4, and the expansion side check valve V3 is opened, so that the liquid passes through the port 23a and moves from the tank 4 to the pressure side chamber R2. .

During the extension stroke of the rear cushion unit RCU, the flow path area of the rebound damping force adjustment valve EV can be adjusted by external operation, and the resistance that the rebound damping force adjustment valve EV gives to the flow of liquid can be changed. , the rear cushion unit RCU can adjust the damping force on the rebound side. Further, the rebound damping force adjustment passage P4 communicates the growth side chamber R1 and the compression side chamber R2, and is not structured so that the liquid that has passed through the rebound damping force adjustment passage P4 is directly discharged to the tank 4. . Therefore, the flow rate of the liquid passing through the expansion side check valve V3 does not exceed the volume at which the piston rod 3 withdraws from the cylinder 1, so that it is possible to prevent a situation in which the liquid in the cylinder 1 becomes insufficient and becomes negative pressure.

On the other hand, in the contraction stroke of the rear cushion unit RCU in which the piston 2 moves upward in FIG. It moves to the expansion side chamber R1 via the second passage P2. In addition, during the contraction stroke of the rear cushion unit RCU, the piston rod 3 enters into the cylinder 1, so the amount of liquid in the cylinder 1 corresponding to the volume of the piston rod 3 entering into the cylinder 1 becomes excessive. The liquid is discharged to the liquid chamber L in the tank 4 through the pressure side damping valve V1, and the diaphragm 12 contracts to reduce the air chamber G. In this way, during the contraction stroke of the rear cushion unit RCU, the pressure side damping valve V1 and the needle valve V4 provide resistance to the flow of liquid from the pressure side chamber R2 toward the tank 4. In this way, during the contraction stroke of the rear cushion unit RCU, the second passage P2 is opened, so that the expansion side chamber R1 and the compression side chamber R2 in the cylinder 1 are in communication, and the compression side damping valve V1 and the needle valve V4 are connected to the compression side. Provides resistance to the flow of liquid from chamber R2 to tank 4. Therefore, in the contraction stroke of the rear cushion unit RCU, the pressures in both the expansion side chamber R1 and the compression side chamber R2 increase to become approximately the same pressure. In the rear cushion unit RCU of this embodiment, the area of the piston 2 facing the expansion side chamber R1 is smaller than the area of the piston 2 facing the compression side chamber R2 by the area of the piston rod 3, so that the contraction operation is performed. The rear cushion unit RCU exerts a damping force equal to the pressure inside the cylinder 1 multiplied by the area of the piston rod 3 in a direction that prevents the contraction operation. That is, in the case of the rear cushion unit RCU set as a single rod type in which the piston rod 3 is present only on one side of the piston 2 described above, a damping force proportional to the cross-sectional area of the piston rod 3 is generated during the contraction operation.

Note that in the rear cushion unit RCU of this embodiment, the valve unit V includes the needle valve V4, so the resistance that the needle valve V4 gives to the flow of liquid can be changed by adjusting the flow path area in the needle valve V4. , the rear cushion unit RCU is capable of adjusting the damping force on the compression side.

In addition, during the contraction stroke of the rear cushion unit RCU, when the differential pressure between the pressure in the pressure side chamber R2 and the pressure in the tank 4 reaches the opening pressure of the pressure side relief valve V2, the ball 34 retreats from the relief valve seat 36. Since the pressure side relief valve V2 is opened, the pressure side chamber R2 and the tank 4 are communicated with each other through the pressure side relief passage PV2. By opening the pressure side relief passage PV2, the liquid in the cylinder 1 escapes to the tank 4, and the pressure in the cylinder 1 is adjusted so as not to exceed the opening pressure of the pressure side relief valve V2.

Here, in a rear cushion unit used in a relatively lightweight straddle-type vehicle M, the outer diameter of the piston rod may be made thinner because there is no problem in terms of strength and the weight of the rear cushion unit can be reduced. The damping force generated when the rear cushion unit is retracted is proportional to the cross-sectional area of the piston rod, as described above. Therefore, if such a rear cushion unit is to exhibit a large damping force during contraction while reducing the outer diameter of the piston rod, the pressure inside the cylinder must be high. In order to make the pressure inside the cylinder high during the contraction operation, it is sufficient to increase the resistance that the pressure-side damping valve V1 gives to the flow of liquid. However, if the rear cushion unit RCU is contracted at high speed during the contraction operation, The pressure may become so great that it exceeds the withstand pressure of the seal member that seals the outer periphery of the piston rod. However, in the rear cushion unit RCU of the present embodiment, as described above, the valve unit V includes the compression side relief valve V2 arranged in parallel to the compression side damping valve V1. Therefore, even if the contraction speed of the rear cushion unit RCU becomes high during the contraction operation of the rear cushion unit RCU, the pressure side relief valve V2 can be prevented from opening and the pressure inside the cylinder 1 will be prevented from becoming excessive, and the piston rod It is possible to protect the seal member 8 that seals the outer periphery of the piston rod 3 and prevent leakage of liquid from between the piston rod 3 and the seal member 8.

Further, when the valve unit V is removed from the upper cap 11 and the opening of the second valve case 11e is closed with a cap (not shown), the pressure side chamber R2 and the tank 4 are communicated with each other without any valve, so the rear cushion unit The RCU generates damping force only during extension operation and does not generate damping force during retraction operation. In this way, by installing the valve unit V, the rear cushion unit RCU can exert damping force both during the extension operation and during the contraction operation, but if the valve unit V is removed from the rear cushion unit RCU, the damping force will be exerted during the extension operation. This is the only rear cushion unit that generates damping force.

As described above, the rear cushion unit RCU of the present embodiment is interposed between the body F and the rear wheel W of the straddle-type vehicle M, and is movably inserted into the cylinder 1 and inside the cylinder 1. A piston 2 that divides the cylinder into a expansion side chamber R1 and a compression side chamber R2 filled with liquid, a piston rod 3 that is movably inserted into the cylinder 1 and connected to the piston 2, and a tank 4 that stores liquid. , a first passage P1 and a second passage P2 that connect the expansion side chamber R1 and the compression side chamber R2 in parallel, respectively, a third passage P3 that communicates the compression side chamber R2 and the tank 4, and are provided outside the cylinder 1. a rebound-side damping force adjustment passage P4 that connects the growth-side chamber R1 and the compression-side chamber R2; and a rebound-side damping valve that is provided in the first passage P1 and provides resistance to the flow of liquid from the growth-side chamber R1 to the compression-side chamber R2. 5, a compression side check valve 6 which is provided in the second passage P2 and allows only the flow of liquid from the compression side chamber R2 toward the rebound side chamber R1, and a compression side check valve 6 which is provided in the rebound side damping force adjustment passage P4 and allows the flow of liquid from the compression side chamber R2 to the rebound side chamber R1, and which is provided in the rebound side damping force adjustment passage P4 and allows the liquid to flow from the compression side chamber R2 to the rebound side chamber R1. It is equipped with an expansion side damping force adjustment valve EV that can change the flow path area.

In the rear cushion unit RCU configured as described above, the piston 2 is equipped with a rebound damping valve 5, and a rebound damping valve 5 provided outside the cylinder 1 is a rebound damping valve that can change the flow path area with a compact configuration. Since it is a force adjustment valve EV, it is possible to adjust the damping force during the extension operation while avoiding increasing the external size of the rear cushion unit RCU.

Further, the rebound damping force adjustment valve EV is provided in the rebound damping force adjustment passage P4 provided outside the cylinder 1, and when the rear cushion unit RCU is attached to the saddle type vehicle M, the rebound damping force adjustment valve EV is It is installed on the cylinder 1 side that is connected to the side. In this way, when the rear cushion unit RCU is attached to the saddle type vehicle M, the cylinder 1 is placed on the vehicle body F side and the piston rod 3 is placed on the rear wheel W side, but the rebound side damping force adjustment valve EV is placed on the cylinder side. Since it is disposed on the first side, the user can easily operate the rebound damping force adjustment valve EV.

As described above, according to the rear cushion unit RCU of the present embodiment, even if it is provided with the rebound damping force adjustment valve EV, it is possible to avoid increasing the size, and therefore it is possible to improve the ease of mounting on the rear wheel side of the saddle type vehicle M. At the same time, it is possible to easily adjust the damping force during the extension operation.

Furthermore, the rear cushion unit RCU of this embodiment includes an outer cylinder 15 that covers the cylinder 1 and forms a rebound damping force adjustment passage P4 between the cylinder 1 and the outer cylinder 15, and is attached to the upper end of the cylinder 1 and the outer cylinder 15. The upper cap 11 is provided with a bracket B1 that holds the tank 4 and is connectable to the vehicle body F, and a rebound damping force adjustment valve EV is provided on the upper cap 11. According to the rear cushion unit RCU configured in this way, by providing the outer cylinder 15, the rebound damping force adjustment passage P4 can be installed outside the cylinder 1 with a simple structure, and the rebound damping force adjustment valve EV can be installed. Since it is provided in the upper cap 11, the rebound damping force adjustment valve EV can be arranged at the upper end of the rear cushion unit RCU. Therefore, according to the rear cushion unit RCU, since the rebound damping force adjustment valve EV is disposed at the upper end, the user can operate the rebound damping force adjustment valve EV without being obstructed by the muffler or the like of the straddle-type vehicle M. .

In the rear cushion unit RCU of the present embodiment, the rebound side damping force adjustment valve EV has an annular valve seat 50 and a valve head 51b that is axially shaped and can move toward and away from the annular valve seat 50 at its tip. The valve head 51b is arranged in a range between the cylinder 1 and the outer cylinder 15 when the cylinder 1 and the outer cylinder 15 are viewed from the axial direction. According to the rear cushion unit RCU configured in this way, the rebound damping force adjustment valve EV is located as close as possible to the axis LC of the cylinder 1 while being located close to the ends of the cylinder 1 and the outer cylinder 15. Therefore, even if the rebound damping force adjustment valve EV is provided, the overall length of the rear cushion unit RCU does not increase and the size of the rear cushion unit RCU does not increase in the radial direction.

Further, the rear cushion unit RCU of the present embodiment includes a valve unit V provided in the middle of the third passage P3, and the valve unit V is configured on the pressure side to provide resistance to the flow of liquid from the pressure side chamber R2 toward the tank 4. The damping valve V1 is arranged in parallel with the pressure side damping valve V1, and when the valve is closed, the communication between the pressure side chamber R2 and the tank 4 is cut off, and the differential pressure between the pressure in the pressure side chamber R2 and the pressure in the tank 4 reaches the valve opening pressure. Then, a pressure-side relief valve V2 opens and allows liquid to flow from the pressure-side chamber R2 to the tank 4, and an expansion valve V2, which is arranged in parallel with the pressure-side damping valve V1 and only allows liquid to flow from the tank 4 to the pressure-side chamber R2, opens. It is provided with a side check valve V3 and a needle valve V4 which is arranged in parallel with the pressure side damping valve V1, provides resistance to the flow of liquid from the pressure side chamber R2 toward the tank 4, and is capable of adjusting the flow path area.

According to the rear cushion unit RCU configured in this way, the valve unit V, which includes the compression side damping valve V1, the compression side relief valve V2, and the expansion side check valve V3 in parallel, connects the compression side chamber R2 and the tank 4. Since it is removably provided in the middle of the three passages P3, it is possible to exert a damping force not only during the extension operation but also during the contraction operation, and it is also possible to adjust the damping force during the contraction operation. Furthermore, according to the rear cushion unit RCU configured as described above, since the valve unit V is provided with the pressure side relief valve V2, the contraction speed of the rear cushion unit RCU is high when the rear cushion unit RCU is compressed. Even if this happens, the pressure inside the cylinder 1 can be prevented from becoming excessive.

In the rear cushion unit RCU of this embodiment, depending on the presence or absence of the valve unit V, the rear cushion unit RCU can be divided into a rear cushion unit that generates a damping force during both extension and contraction operations, and a rear cushion unit that generates damping force during extension operation. Can be set to either one with the rear cushion unit that only generates damping force. The manufacturer of the rear cushion unit RCU can assemble the rear cushion unit RCU other than the valve unit V with the same parts on the same line, and can assemble the rear cushion unit RCU by determining whether or not the valve unit V is included according to the user's request. Can be manufactured. Therefore, the manufacturer can reduce the manufacturing cost of the rear cushion unit RCU.

Further, in the rear cushion unit RCU of the present embodiment, the upper cap 11 includes a cap portion 11a attached to the upper ends of the cylinder 1 and the outer cylinder 15, a tank holding portion 11b that holds the tank 4, and a cap portion 11a. A connection part 11c extends from the side of the tank holding part 11b and forms a third passage P3, and the extension side damping force adjustment valve EV and the valve unit V are connected to the cap part 11a at the connection part 11c. They are arranged on both sides of 11c.

According to the rear cushion unit RCU configured in this way, the rebound damping force adjustment valve EV and the valve unit V are provided in the upper cap 11 at the upper end of the rear cushion unit RCU, which is easily accessible to the user. Further, the rear cushion unit RCU is normally installed in the saddle type vehicle M with the tank 4 facing either the front or the rear of the saddle type vehicle M, but in any case, the rebound damping force adjustment Since the valve EV and the valve unit V are arranged on both sides sandwiching the connection part 11c connected to the tank holding part 11b in the circumferential direction, both the rebound damping force adjustment valve EV and the valve unit V are located inside the vehicle body F. This will prevent you from being in a situation where you are faced with the situation. Therefore, with the rear cushion unit RCU configured in this manner, even if the mounting position on the straddle-type vehicle M changes depending on the specifications of the straddle-type vehicle M, the user can easily adjust the rebound damping force adjustment valve EV and the valve. Easy to operate with Unit V.

Further, the rebound damping force adjustment valve EV and the valve unit V may be disposed at positions offset from the tank 4 in the circumferential direction when the upper cap 11 is viewed from the axial direction. Even if the rear cushion unit RCU is installed in the straddle-type vehicle M in a posture facing either the front or the rear, it is also possible to have both the rebound damping valve EV and the valve unit V facing the outside of the vehicle body F. . According to the rear cushion unit RCU configured in this way, even if the mounting position on the saddle type vehicle M changes depending on the specifications of the saddle type vehicle M, the user can easily adjust the rebound damping force adjustment valve EV and the valve unit V. Easy to operate.

Furthermore, in the rear cushion unit RCU of the present embodiment, the upper cap 11 includes a first valve hole h1 that accommodates the rebound damping force adjustment valve EV, and a second valve hole h2 that accommodates the valve unit V. The first valve hole h1 and the second valve hole h2 are arranged radially around the axis LC of the cylinder 1. In the rear cushion unit RCU configured in this way, the first valve hole h1 and the second valve hole h2 are arranged radially around the axis LC of the cylinder 1, so that the rebound damping force adjustment valve EV and the valve The units V are similarly attached radially to the upper cap 11. In a layout in which the rebound damping force adjustment valve EV and the valve unit V are arranged in parallel, the rebound damping force adjusting valve EV and the valve unit V protrude to the side of the upper cap 11. When the damping force adjustment valve EV and the valve unit V are attached radially to the upper cap 11, the amount of lateral protrusion can be reduced. Therefore, in the rear cushion unit RCU configured in this way, even if it is provided with the rebound damping force adjustment valve EV and the valve unit V, the amount of overhang in the radial direction can be reduced and the size can be reduced. Easily mounted on M.

In the rear cushion unit RCU of this embodiment, the needle valve V4 includes an annular valve seat 33 and a needle 22 that can be moved closer to or closer to the annular valve seat 33, and the pressure side relief valve V2 is housed in the needle 22. There is. According to the rear cushion unit RCU configured in this way, the pressure side relief valve V2 is accommodated in the needle 22, so that the entire valve unit V can be downsized. In addition, since the pressure side relief valve V2 is accommodated in the needle 22, the opening pressure of the pressure side relief valve V2 can be kept constant regardless of the position of the needle 22.

Furthermore, in the rear cushion unit RCU of the present embodiment, the needle 22 is cylindrical and is provided at an intermediate portion between the outer periphery and the needle portion 22a1 that is provided on the outer periphery of the tip and can be inserted into the inside of the annular valve seat 33. The head 22a has a flange 22a2 that can be seated on and taken off from the annular valve seat 33, and the inside and outside communicate with a groove (operation part) 22b3, which has a bottomed cylindrical shape and is formed in the bottom part 22b2 and allows operation from the outside. The pressure side relief valve V2 has an annular rear end 22a3 of the head 22a as an annular relief valve seat 36. , a valve body 30 that can be attached to and detached from the relief valve seat 36 and is housed in the operation tube 22b, and a valve body 30 that is interposed between the valve body 30 and the operation tube 22b and housed in the operation tube 22b. It has a spring 31 that urges the valve body 30 toward the relief valve seat 36, and when the valve body 30 is separated from the relief valve seat 36, the inside of the head 22a and the through hole 22b4 are communicated. There is.

According to the rear cushion unit RCU configured in this way, a space is provided in the head 22a of the needle 22 and a space for accommodating the valve body 30 and the spring 31 in the operation tube 22b, so that the head 22a constituting the needle 22 is By using it as the relief valve seat 36, the pressure side relief valve V2 can be easily housed within the needle 22. Therefore, according to the rear cushion unit RCU configured in this way, the pressure side relief valve V2 and the needle 22 can be further downsized.

Furthermore, the rear cushion unit RCU of the present embodiment includes a seal member 8 that slides on the outer periphery of the piston rod 3 to seal the outer periphery of the piston rod 3. The pressure is set below the maximum pressure that can be withstood. According to the rear cushion unit RCU configured in this way, since the pressure inside the cylinder 1 does not exceed the maximum pressure that the seal member 8 can withstand, protection of the seal member 8 and protection from the gap between the piston rod 3 and the seal member 8 are avoided. can prevent liquid leakage.

Although the preferred embodiments of the present invention have been described in detail above, modifications, variations, and changes are possible without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Piston, 3... Piston rod, 4... Tank, 5... Rebound side damping valve, 6... Compression side check valve, 11... Upper cap, 11a ... Cap part, 11b... Tank holding part, 11c... Connection part, 15... Outer cylinder, 50... Annular valve seat, 51... Valve body, 51b... Valve head, B1, B2...Bracket, EV...Rebound damping force adjustment valve, F...Vehicle body, LC...Cylinder axis, M...Saddle type vehicle, h1...First valve hole, h2 ...Second valve hole, P1...First passage, P2...Second passage, P3...Third passage, P4...Rebound damping force adjustment passage, R1...Rebound side chamber, R2...Compression side chamber, RCU...Rear cushion unit, V...Valve unit, V1...Valve unit, V2...Compression side relief valve, V3...Rebound side check valve, V4... Needle valve, W...rear wheel

Claims

A rear cushion unit interposed between a body and a rear wheel of a straddle-type vehicle,
cylinder and
a piston that is movably inserted into the cylinder and divides the cylinder into a growth side chamber and a pressure side chamber filled with liquid;
a piston rod movably inserted into the cylinder and connected to the piston;
A tank for storing liquid,
a first passage and a second passage that connect the expansion side chamber and the compression side chamber in parallel, respectively;
a third passage communicating the pressure side chamber and the tank;
a rebound damping force adjustment passage provided outside the cylinder and communicating the rebound chamber and the compression chamber;
a growth-side damping valve that is provided in the first passage and provides resistance to the flow of liquid from the growth-side chamber toward the compression-side chamber;
a pressure side check valve that is provided in the second passage and allows only the flow of liquid from the pressure side chamber toward the expansion side chamber;
A rear cushion unit comprising: a rebound damping force adjustment valve that is provided in the rebound damping force adjustment passage and whose flow path area can be changed by operating from the outside.
an outer cylinder that covers the cylinder and forms the rebound damping force adjustment passage between the cylinder and the cylinder;
an upper cap having a bracket attached to the upper ends of the cylinder and the outer cylinder to hold the tank and connectable to the vehicle body;
The rear cushion unit according to claim 1, wherein the rebound damping force adjustment valve is provided in the upper cap.
The expansion side damping force adjustment valve has an annular valve seat, and a valve body that is shaft-shaped and has a valve head at its tip that can be moved toward and away from the annular valve seat,
The rear cushion unit according to claim 2, wherein the valve head is arranged in a range between the cylinder and the outer cylinder when the cylinder and the outer cylinder are viewed from the axial direction.
comprising a valve unit provided in the middle of the third passage,
The valve unit includes:
a pressure-side damping valve that provides resistance to the flow of liquid from the pressure-side chamber toward the tank;
A valve is disposed in parallel with the pressure side damping valve, and cuts off communication between the pressure side chamber and the tank when the valve is closed, and opens the valve when the differential pressure between the pressure in the pressure side chamber and the pressure in the tank reaches a valve opening pressure. a pressure side relief valve that allows liquid to flow from the pressure side chamber toward the tank;
an expansion side check valve that is arranged in parallel with the compression side damping valve and allows only the flow of liquid from the tank to the compression side chamber;
The rear cushion according to claim 2, further comprising a needle valve arranged in parallel with the pressure side damping valve to provide resistance to the flow of liquid from the pressure side chamber to the tank and to be able to adjust a flow path area. unit.
The upper cap is
a cap portion attached to the upper ends of the cylinder and the outer tube;
a tank holding part that holds the tank;
a connecting portion that extends from a side of the cap portion, is connected to the tank holding portion, and forms the third passage, and the rebound damping force adjustment valve and the valve unit are connected to the cap portion. The rear cushion unit according to claim 4, wherein the rear cushion unit is arranged on both sides of the connecting portion.
The upper cap is
a first valve hole that accommodates the expansion side damping force adjustment valve;
a second valve hole that accommodates the valve unit;
The rear cushion unit according to claim 4, wherein the first valve hole and the second valve hole are arranged radially around the axis of the cylinder.