WO2024048059A1

WO2024048059A1 - Suspension device

Info

Publication number: WO2024048059A1
Application number: PCT/JP2023/024577
Authority: WO
Inventors: 修宮崎; 渓須崎
Original assignee: カヤバモーターサイクルサスペンション株式会社
Priority date: 2022-08-31
Filing date: 2023-07-03
Publication date: 2024-03-07
Also published as: JP2024033801A

Abstract

A suspension device (S) comprises a first front fork (F1x) and a second front fork (F2y). The first front fork (F1x) is provided with an extension-side adjustment part (22x), which is capable of adjusting a resistance applied to a flow of liquid passing through an extension-side damping force adjustment passage (20x) by an extension-side damping force adjustment valve (21x), on a first cap (5x) that seals the upper end of a first vehicle body-side tube (3x), and the second front fork (F2y) is provided with an pressure-side adjustment part (25y), which is capable of adjusting a resistance applied to a flow of liquid passing through a pressure-side damping force adjustment passage (23y) by a pressure-side damping force adjustment valve (24y), on a second cap (5y) that seals the upper end of a second vehicle body-side tube (3y).

Description

suspension system

The present invention relates to a suspension device.

Conventionally, a suspension system interposed between the body of a saddle-side vehicle and a front wheel is configured to include a pair of left and right front forks, and each front fork has a built-in damper.

More specifically, each front fork includes, for example, a vehicle-side tube, an axle-side tube that is movable relative to the vehicle-side tube in the axial direction, a cap that closes the upper end of the vehicle-side tube, and a lower end of the axle-side tube. The fork body includes an axle bracket that closes the front wheel and holds the axle of the front wheel, and a damper that is housed in the fork body.

The damper also includes a cylinder whose lower end is fixed to the axle bracket, a piston rod whose upper end is connected to the cap and inserted into the cylinder, and a cylinder which is attached to the tip of the piston rod and is slidable inside the cylinder. A piston that is inserted into the cylinder to divide the inside of the cylinder into a growth side chamber and a compression side chamber, and a piston that is inserted into the lower side of the cylinder and communicates with a reservoir outside the cylinder through a hole provided in the cylinder and a compression side chamber. The valve disk that partitions the space between the two, the expansion side port and the compression side port provided on the piston, the expansion side leaf valve that opens and closes the expansion side port and provides resistance to the flow of liquid from the expansion side chamber to the compression side chamber, and the compression side port. A pressure side check valve that opens and closes to allow only liquid to flow from the compression side chamber to the expansion side chamber, a compression side damping port and a suction port provided on the valve disk, and a pressure side check valve that opens and closes the compression side damping port to allow liquid to flow from the compression side chamber to the reservoir. The pressure side leaf valve provides resistance to the flow of liquid, and the expansion side check valve opens and closes the suction port to allow only the flow of liquid from the reservoir to the pressure side chamber.

As disclosed in JPH11-201214A or JPH06-56532U, in a suspension system, in order to enable adjustment of the damping force generated by the dampers in the left and right front forks, the dampers have a piston rod in addition to the above structure. A recovery side damping force adjustment passage that bypasses the recovery side port and communicates the recovery side chamber and the compression side chamber, a recovery side needle valve provided in the middle of the recovery side damping force adjustment passage, and a recovery side damping force adjustment passage provided in the axle bracket. The pressure side damping force adjustment passage communicates the compression side chamber and the reservoir, and the compression side needle valve is provided in the middle of the compression side damping force adjustment passage. In the suspension system configured in this way, the flow path area of the rebound needle valve can be adjusted by operating the rebound adjuster provided on the cap of the fork body, and the rebound damping force when the damper is extended can be adjusted. The pressure side damping force when the damper contracts can be adjusted by operating the pressure side adjuster provided on the axle bracket.

JPH11-201214A JPH06-56532U

In conventional suspension systems, the rebound damping force and compression damping force of the damper in each front fork can be adjusted independently, but since the compression side adjuster is provided on the axle bracket at the lower end of the front fork, the compression damping force can be adjusted independently. To make the adjustment, the user must get out of the vehicle, bend down, and operate the compression side adjuster. As described above, adjusting the compression damping force in conventional suspension systems is a troublesome task, and there is a need for a suspension system that can not only adjust the rebound damping force but also the compression damping force at the upper end of the front fork. has been done.

Furthermore, when considering the case where the compression side damping force is adjusted using an actuator, the conventional suspension system has a structure in which the actuator is placed close to the ground, so the conventional suspension system is not suitable for installing the actuator.

Therefore, an object of the present invention is to provide a suspension device that can adjust the rebound damping force and the compression damping force on the upper end side of the front fork.

In order to solve the above-mentioned problems, the suspension system of the present invention includes a first front fork and a second front fork that suspend the front wheels of a straddle-type vehicle on the vehicle body, and the first front fork is connected to a first vehicle body side tube. , a first axle-side tube that is movable in the axial direction with respect to the first vehicle-side tube; a first cap that closes the upper end of the first vehicle-side tube; and a first cap that closes the lower end of the first axle-side tube and that is a first fork body that is extendable and retractable and has a first axle bracket that holds an axle; a first cylinder that is connected to the first axle bracket; and a first cylinder that is movably inserted in the first cylinder in the axial direction; a first piston rod whose upper end is connected to the first cap; and a first piston rod which is connected to the first piston rod and inserted into the first cylinder to partition the inside of the first cylinder into a first expansion side chamber and a first pressure side chamber. a first piston, and a first damper that expands and contracts with the expansion and contraction of the first fork body to generate a damping force that prevents expansion and contraction of the first fork body; The second front fork includes a second body-side tube and a second axle-side tube that is movable in the axial direction with respect to the second body-side tube. a second fork body that is extendable and retractable, and includes a second cap that closes the upper end of the second vehicle body side tube; and a second axle bracket that closes the lower end of the second axle side tube and holds the axle of the front wheel; , a second cylinder coupled to the second axle bracket; a second piston rod inserted movably in the axial direction into the second cylinder and coupled at an upper end to the second cap; and coupled to the second piston rod. and a second piston that is inserted into the second cylinder and partitions the inside of the second cylinder into a second expansion side chamber and a second pressure side chamber, and expands and contracts as the second fork body expands and contracts. and a second damper that generates a damping force that prevents expansion and contraction of the second fork body, forming a second reservoir that stores liquid in a space between the second fork body and the second damper. The first damper includes a rebound damping force adjustment passage that communicates the first rebound chamber and the first compression chamber, a rebound damping force adjustment valve provided in the middle of the rebound damping force adjustment passage, and a first cap. The second damper has a second pressure side adjustment section that allows the second damper to adjust the resistance given to the flow of liquid passing through the second piston rod. A compression side damping force adjustment passage communicating with the chamber and the second reservoir, a compression side damping force adjustment valve provided in the middle of the compression side damping force adjustment passage, and a compression side damping force adjustment valve provided in the second cap communicating with the compression side damping force adjustment passage. and a pressure side adjustment section that can adjust the resistance given to the flow of liquid passing through the pressure side adjustment section. According to the suspension system configured in this way, the rebound damping force and the compression damping force can be adjusted at the upper end sides of the first front fork and the second front fork.

FIG. 1 is a front view of a straddle-type vehicle to which a suspension system according to an embodiment of the present invention is applied. FIG. 2 is a sectional view of a first front fork of a suspension system according to an embodiment of the present invention. FIG. 3 is a sectional view of the second front fork of the suspension system according to an embodiment of the present invention. FIG. 4 is a sectional view of a second front fork that accommodates a modified example of the second damper.

The present invention will be described below based on the embodiments shown in the figures. As shown in FIG. 1, the suspension system S in one embodiment includes a first front fork F1x and a second front fork F2y, and is attached to a front wheel W of a body B of a saddle type vehicle V such as a motorcycle or a trike. is suspended.

Hereinafter, each part of the suspension system S will be explained in detail. Note that the first front fork F1x and the second front fork F2y have some members in common with each other, and when explaining each part of the first front fork F1x and the second front fork F2y, the names of the members will be used in this manual. When "first" and "second" are not added in front, unless otherwise specified, both the first front fork F1x and the second front fork F2y are shown. Additionally, in this book, if the code attached to a member has an x at the end, it indicates that it is a part of the first front fork F1x, and if the code attached to a member has a y at the end, it indicates that it is a part of the first front fork F1x. This indicates that it is a part of front fork F2y.

As shown in FIG. 1, the suspension system S includes a first front fork F1x, a second front fork F2y, and a pair of upper and lower brackets 1, 2 that grip the upper ends of the first front fork F1x and the second front fork F2y. It is equipped with The brackets 1 and 2 are attached to a steering shaft that is rotatably inserted into a head pipe P provided at the tip of a vehicle body B of a saddle-type vehicle V, and are attached to a steering shaft that is rotatably inserted into a head pipe P provided at the tip of a vehicle body B of a straddle-type vehicle V. Rotatably connected. The first front fork F1x and the second front fork F2 are held at their upper ends by brackets 1 and 2 that are rotatably connected to the vehicle body B in the circumferential direction of the head pipe P, and at their lower ends are the axle Ws of the front wheel W. are connected. In this way, the suspension system S suspends the front wheel W from the body B of the straddle-type vehicle V using the pair of left and right front forks F1x, F2y.

As shown in FIG. 2, the first front fork F1x includes a first body-side tube 3x, a first axle-side tube 4x that is movable in the axial direction with respect to the first body-side tube 3x, and a first body-side tube 4x. The first fork body Fx is extendable and has a first cap 5x that closes the upper end of the first axle tube 3x, and a first axle bracket 6x that closes the lower end of the first axle side tube 3x and holds the axle Ws of the front wheel W. and a first damper Dx housed within the first fork body Fx. Further, as shown in FIG. 3, the second front fork F2y includes a second body side tube 3y, a second axle side tube 4y that is movable in the axial direction with respect to the second body side tube 3y, and a second body side tube 4y. An extendable second fork that includes a second cap 5y that closes the upper end of the side tube 3y, and a second axle bracket 6y that closes the lower end of the second axle side tube 4y and holds the axle Ws of the front wheel W. It includes a main body Fy and a second damper Dy housed within the second fork main body Fy.

As shown in FIGS. 2 and 3,

caps

5x and 5y are attached to the open ends of the upper ends of the vehicle

body side tubes

3x and 3y, and the upper ends of the vehicle

body side tubes

3x and 3y are closed by the

caps

5x and 5y. ing. The

caps

5x, 5y have annular outer ring parts 5ax, 5ay that are screwed onto the inner peripheries of the upper ends of the vehicle

body side tubes

3x, 3y, and project downward in the figure from the inner peripheries of the outer ring parts 5ax, 5ay. The

piston rods

11x, 11y have inner cylinder portions 5bx, 5by screwed onto the upper ends of the

piston rods

11x, 11y. Moreover, a pair of elongated holes 5cx, 5cy are provided in the inner cylinder parts 5bx, 5by of the

caps

5x, 5y, which face each other in the radial direction and extend along the axial direction of the inner cylinder parts 5bx, 5by.

The

axle side tubes

4x, 4y are inserted into the

body side tubes

3x, 3y from below the

body side tubes

3x, 3y, and can move relative to the

body side tubes

3x, 3y in the axial direction. Note that

annular bushes

7x, 7y and

annular seal members

8x, 8y are provided on the inner peripheries of the lower ends of the vehicle

body side tubes

3x, 3y, and are in sliding contact with the outer peripheries of the

axle side tubes

4x, 4y.

Annular bushes

9x, 9y are attached to the outer peripheries of the upper ends of the

tubes

4x, 4y, and are in sliding contact with the inner peripheries of the vehicle

body side tubes

3x, 3y. Therefore, the vehicle

body side tubes

3x, 3y and the

axle side tubes

4x, 4y can be moved in the axial direction without any axial deviation due to the

bushes

7x, 7y, 9x, 9y.

The lower ends of the

axle side tubes

4x, 4y are closed by

axle brackets

6x, 6y that grip the axle Ws of the front wheel W, and the fork bodies Fx, Fy are connected to the front wheel W by the

axle brackets

6x, 6y. The interiors of the fork bodies Fx and Fy configured in this manner are spaces sealed from the outside by

seal members

8x and 8y. The

axle brackets

6x, 6y have bottomed cylindrical portions 6ax, 6ay which are cylindrical and are screwed to the outer peripheries of the lower ends of the

axle side tubes

4x, 4y, and the

axle brackets

6x, 6y are connected to the bottoms of the cylindrical portions 6ax, 6ay. It includes gripping parts 6bx and 6by for gripping Ws. Although not shown in the drawings, the

axle brackets

6x and 6y are provided with attachment portions to which brake calipers, fenders, and the like can be attached.

The first damper Dx includes a first cylinder 10x connected to a first axle bracket 6x, and a first piston that is inserted movably in the axial direction into the first cylinder 10x and whose upper end is connected to the first cap 5x. a rod 11x, and a first piston rod connected to the first piston rod 11x and inserted into the first cylinder 10x to partition the first cylinder 10x into a first expansion side chamber R1x and a first pressure side chamber R2x filled with liquid. 1 piston 12x, and expands and contracts with the expansion and contraction of the first fork body Fx to generate a damping force that prevents the expansion and contraction of the first fork body Fx. When the first damper Dx is accommodated in the first fork body Fx in this manner, a reservoir Rx in which liquid is stored is formed outside the first damper Dx and inside the first fork body Fx. Furthermore, the first damper Dx includes a rebound damping force adjustment passage 20x that communicates the first growth side chamber R1x and the first pressure side chamber R2x, and a rebound damping force adjustment valve provided in the middle of the rebound damping force adjustment passage 20x. 21x, and a rebound adjuster 22x, which is provided in the first cap 5x and serves as a rebound adjustment section capable of adjusting the resistance that the rebound damping force adjustment valve 21x gives to the flow of liquid passing through the rebound damping force adjustment passage 20x. It is equipped with

The second damper Dy also includes a second cylinder 10y connected to the second axle bracket 6y, and a second cylinder 10y that is inserted movably in the axial direction into the second cylinder 10y and whose upper end is connected to the second cap 5y. The second piston rod 11y is connected to the second piston rod 11y and inserted into the second cylinder 10y, dividing the second cylinder 10y into a second expansion side chamber R1y and a second pressure side chamber R2y, which are filled with liquid. The second piston 12y expands and contracts with the expansion and contraction of the second fork body Fy, and generates a damping force that prevents the expansion and contraction of the second fork body Fy. When the second damper Dy is accommodated in the second fork body Fy in this manner, a second reservoir Ry in which liquid is stored is formed outside the second damper Dy and inside the second fork body Fy. Furthermore, the second damper Dy has a compression side damping force adjustment passage 23y that communicates with the second pressure side chamber R2y and the second fork body Fy to the outside of the second cylinder 10y through the second piston rod 11y. A compression side damping force adjustment valve 24y provided in the middle of the damping force adjustment passage 23y and a compression side damping force adjustment valve 24y provided on the second cap 5y adjust the resistance given to the flow of liquid passing through the compression side damping force adjustment passage 23y. The pressure side adjuster 25y is provided as a possible pressure side adjustment section.

Hereinafter, the members constituting the first damper Dx and the second damper Dy will be explained. The

cylinders

10x, 10y are connected to the

axle brackets

6x, 6y via

base valve assemblies

13x, 13y that are fixed to the

axle brackets

6x, 6y in the fork bodies Fx, Fy. The

cylinders

10x, 10y are provided with through holes 10ax, 10ay that open from the sides of the lower ends and communicate the insides of the

cylinders

10x, 10y with the reservoirs Rx, Ry. Further, annular rod guides 15x, 15y are attached to the upper open ends of the

cylinders

10x, 10y. The rod guides 15x, 15y have annular guide portions 15ax, 15ay that are in sliding contact with the outer peripheries of the

piston rods

11x, 11y that are screwed onto the inner peripheries of the upper ends of the

cylinders

10x, 10y and are inserted into the inner peripheries, and guide portions 15ay. It includes cylindrical case parts 15bx and 15by that protrude upward from the upper ends of 15ax and 15ay. Although the liquid filled in the

cylinders

10x, 10y and the reservoirs Rx, Ry is hydraulic oil in the suspension system S of this embodiment, it may be a liquid other than hydraulic oil.

The

base valve assemblies

13x, 13y include annular partitions 13ax, 13ay that fit above the through holes 10ax, 10ay of the

cylinders

10x, 10y, and bottoms of the cylindrical portions 6ax, 6ay of the

axle brackets

6x, 6y. The holding members 13bx, 13by are fixed to the

axle brackets

6x, 6y by penetrating

bolts

14x, 14y, are screwed into the lower ends of the

cylinders

10x, 10y, and hold the partition bodies 13ax, 13ay. The holding members 13bx, 13by include closing portions 13b1x, 13b1y which are the lower ends of the

cylinders

10x, 10y and which are screwed into the inner peripheries below the through holes 10ax, 10ay to close the lower ends of the

cylinders

10x, 10y; It includes shaft portions 13b2x, 13b2y that protrude upward from the shaft portions 13b1x, 13b1y, and have the partition walls 13ax, 13ay attached to their outer peripheries. In this way, the spaces within the

cylinders

10x, 10y between the partitions 13ax, 13ay and the closing parts 13b1x, 13b1y are communicated with the reservoirs Rx, Ry via the through holes 10ax, 10ay, and the partitions 13ax and 13ay partition the inside of the

cylinders

10x and 10y into pressure side chambers R2x and R2y and spaces communicating with reservoirs Rx and Ry.

Further, the partition bodies 13ax, 13ay are provided with pressure side damping passages 13a1x, 13a1y and suction passages 13a2x, 13a2y that communicate the pressure side chambers R2x, R2y with the space. The pressure side damping passages 13a1x, 13a1y are provided with pressure

side damping valves

32x, 32y that provide resistance to the flow of liquid from the pressure side chambers R2x, R2y toward the reservoirs Rx, Ry, and the suction passages 13a2x, 13a2y are provided with Extension

side check valves

33x, 33y are provided that allow only the flow of liquid from the reservoirs Rx, Ry to the pressure side chambers R2x, R2y.

The

piston rods

11x, 11y include cylindrical piston rod bodies 11ax, 11ay, and cylindrical center rods 11bx, 11by that are connected to the lower ends of the piston rod bodies 11ax, 11ay and hold the

pistons

12x, 12y. . The

piston rods

11x, 11y have their upper ends connected to the inner cylindrical parts 5bx, 5by of the

caps

5x, 5y by screwing, and their lower ends inserted into the

cylinders

10x, 10y through the inner circumferences of the rod guides 15x, 15y. ing. The

piston rods

11x, 11y move along with the

pistons

12x, 12y in the axial direction, in the vertical direction in the figure, while their radial movement with respect to the

cylinders

10x, 10y is restricted by the rod guides 15x, 15y and the

pistons

12x, 12y. Can move relatively.

As shown in FIG. 2, the center rod 11bx of the first piston rod 11x has a cylindrical shape, and includes a large diameter portion 11b1x that is threaded onto the outer periphery of the lower end of the piston rod body 11ax, and an outer diameter larger than the large diameter portion 11b1x. A small diameter portion 11b2x having a small diameter and having a piston 12x attached to its outer periphery, a port 11b3x provided in the large diameter portion 11b1x and penetrating the large diameter portion 11b1x in the radial direction, and a smaller diameter portion 11b2x on the inner periphery than the port 11b3x. The extension side annular valve seat 11b4x is formed by a step provided on the side. An annular lock piece 31x that enters the case portion 15bx of the rod guide 15x when the first damper Dx is fully contracted is provided on the outer periphery of the piston rod body 11ax. When it enters, the pressure within the case portion 15bx is increased to suppress further contraction of the first damper Dx.

Note that the center rod 11bx has a cylindrical shape, and the opening at the tip of the center rod 11bx faces the first compression side chamber R2x, so that the inside of the center rod 11bx communicates with the port 11b3x and the first expansion side chamber R1x. It is in communication with the first pressure side chamber R2x. In this way, the extension damping force adjustment passage 20x is formed inside the piston rod 11x.

The first piston 12x is annular and includes a compression side damping passage 12ax and a compression side passage 12bx that communicate the first expansion side chamber R1x and the first compression side chamber R2x in parallel. It is fitted around the outer periphery.

A growth side damping passage 12ax is opened and closed on the first pressure side chamber R2x side of the first piston 12x, and a flow of liquid passing through the growth side damping passage 12ax from the first growth side chamber R1x toward the first pressure side chamber R2x is controlled. An annular extension damping valve 16x is provided to provide resistance. In the case of the present embodiment, the expansion side damping valve 16x is a leaf valve whose inner circumference is fixed to the center rod 11bx and whose outer circumference is allowed to bend, but it may be a valve other than a leaf valve. Additionally, the number of stacked leaf valves can also be changed in design.

On the first expansion side chamber R1x side of the first piston 12x, there is an annular pressure side that opens and closes the pressure side passage 12bx and allows only the flow of liquid passing through the pressure side passage 12bx from the first pressure side chamber R2x toward the first expansion side chamber R1x. Check valves 17x are stacked one on top of the other. In the case of the present embodiment, the pressure side check valve 17x includes a valve body that is annular and movable in the axial direction with respect to the piston 12x, and a spring that biases the valve body toward the piston 12x. However, valves with other structures may also be used.

Continuing, a growth-side damping force adjustment passage 20x provided in the piston rod 11x has a growth-side needle 21ax that is inserted movably in the axial direction into the piston rod 11x and can be seated on and removed from the growth-side annular valve seat 11b4x. and a spring 21bx that biases the growth side needle 21ax in the direction of separating it from the growth side annular valve seat 11b4x. The expansion-side needle 21ax includes a large-diameter guide portion 21a1x that slides on the inner periphery of the lower end of the piston rod body 11ax, and a conical valve head 21a2x that extends downward from the guide portion 21a1x and seats on and off the expansion-side annular valve seat 11b4x. and a seal ring 21a3x that is attached to the outer periphery of the guide portion 21a1x and comes into sliding contact with the inner periphery of the piston rod body 11ax. Therefore, the extension needle 21ax is guided by the guide portion 21a1x within the piston rod 11x and can move in the axial direction without axial wobbling, and the seal ring 21a3x allows the liquid to overcome the guide portion 21a1x and move upward within the piston rod 11x. It prevents you from doing so.

The growth side damping force adjustment valve 21x can block the growth side damping force adjustment passage 20x when the growth side needle 21ax is seated on the growth side annular valve seat 11b4x, and also causes the growth side needle 21ax to retreat from the growth side annular valve seat 11b4x. and the expansion side damping force adjustment passage 20x are opened, and the gap size (flow path area) between the expansion side needle 21ax and the expansion side annular valve seat 11b4x is adjusted to pass through the expansion side damping force adjustment passage 20x. Adjustable resistance to liquid flow.

The flow path area in the expansion side damping force adjustment valve 21x is adjusted by operating the expansion side adjuster 22x housed in the inner periphery of the first cap 5x. The expansion side adjuster 22x has a threaded portion on its outer periphery, and rotates in the circumferential direction on the inner periphery of a cylindrical spring adjuster 26x that is rotatably mounted in the circumferential direction within the inner cylinder portion 5bx of the first cap 5x. Possibly inserted. A feed screw mechanism is formed by the expansion side adjuster 22x and the spring adjuster 26x, and when the expansion side adjuster 22x is rotated with respect to the spring adjuster 26x, the expansion side adjuster 22x moves in the vertical direction in FIG. 2 within the first cap 5x. Move to. A cylindrical growth-side control rod 27x is inserted between the growth-side adjuster 22x and the growth-side needle 21ax and into the piston rod main body 11ax so as to be movable in the axial direction in the vertical direction in FIG. The vertical displacement of the growth side adjuster 22x is transmitted to the growth side needle 21ax via the growth side control rod 27x. In this way, by operating the growth side adjuster 22x provided on the first cap 5x at the upper end of the first front fork F1x, the flow path area of the growth side damping force adjustment valve 21x can be changed in size.

Note that a threaded portion (not shown) is also formed on the outer periphery of the lower end of the spring adjuster 26x, and a nut 28x is attached to the threaded portion on the outer periphery of the spring adjuster 26x. The nut 28x includes a spring receiver 28ax that protrudes toward the outer circumferential side of the inner cylindrical portion 5bx through the elongated hole 5cx of the inner cylindrical portion 5bx of the first cap 5x. A suspension spring 29x is interposed between the spring receiver 28ax and the upper end of the case portion 15bx of the rod guide 15x, and the suspension spring 29x biases the first fork body Fx to extend. A body B of a straddle-type vehicle V is elastically supported. When the spring adjuster 26x is rotated, the rotation of the nut 28x is restricted by the inner cylindrical portion 5bx, so the nut 28x moves in the vertical direction in FIG. 2, displacing the support position of the suspension spring 29x of the spring receiver 28ax in the vertical direction. The height of the straddle-type vehicle V can be adjusted.

On the other hand, as shown in FIG. 3, the piston rod main body 11ay of the second piston rod 11y is provided with a horizontal hole 11a1y. The piston rod body 11ax in the first piston rod 11x does not have a horizontal hole, but the piston rod body 11ay in the second piston rod 11y has a horizontal hole 11a1y, and in this point, the piston rod body 11ax and the piston rod body The structure is different from 11ay. The horizontal hole 11a1y is located above the case portion 15by and communicates with the second reservoir Ry even when the second damper Dy is most contracted and the piston rod 11y enters the cylinder 10y to the maximum extent. In this way, the horizontal hole 11a1y is always communicated with the second reservoir Ry. Furthermore, even if the second damper Dy is extended to the maximum and the piston rod 11y is moved from the cylinder 10y upward in FIG. It is located in a position that is always lower than the

Furthermore, on the outer periphery of the piston rod main body 11ay and below the horizontal hole 11a1y, there is provided an annular lock piece 31y that enters into the case portion 15by of the rod guide 15y when the second damper Dy is fully contracted. When the lock piece 31y enters the case portion 15by, the pressure within the case portion 15by is increased to suppress further contraction of the second damper Dy.

The center rod 11by of the second piston rod 11y has a cylindrical shape, and includes a large diameter portion 11b1y that is screwed to the lower end outer periphery of the piston rod main body 11ay, and a smaller outer diameter than the large diameter portion 11b1y, and an outer periphery. A small diameter portion 11b2y on which the piston 12y is mounted, and a pressure side annular valve seat 11b3y formed by a stepped portion provided on the inner periphery. The center rod 11bx in the first piston rod 11x is equipped with a port 11b3x, but the center rod 11by in the second piston rod 11y is not equipped with a port, and in this point, the center rod 11bx and the center rod 11by have different structures. It's different.

The piston rod main body 11ay and the center rod 11by are cylindrical, and the opening at the tip of the center rod 11by faces the second pressure side chamber R2y, so that there is no connection between the inside of the second piston rod 11y and the horizontal hole 11a1y. The second pressure side chamber R2y is communicated with the reservoir Ry through the second pressure side chamber R2y. In this way, by making the second piston rod 11y cylindrical, a vertical hole is formed that communicates the horizontal hole 11a1y with the second pressure side chamber R2y, and a compression side damping force adjustment passage is formed inside the second piston rod 11y. 23y is formed.

The second piston 12y is annular and includes a growth side damping passage 12ay and a compression side passage 12by that communicate the second growth side chamber R1y and the second pressure side chamber R2y in parallel. It is fitted around the outer periphery.

A rebound damping passage 12ay is opened and closed on the second pressure side chamber R2y side of the second piston 12y, and the flow of liquid passing through the rebound damping passage 12ay from the second growth side chamber R1y toward the second pressure side chamber R2y is controlled. An annular extension damping valve 16y is provided to provide resistance. In the case of the present embodiment, the expansion side damping valve 16y is a leaf valve whose inner periphery is fixed to the center rod 11by and whose outer periphery is allowed to bend, but it may be a valve other than a leaf valve. Additionally, the number of stacked leaf valves can also be changed in design.

On the second expansion side chamber R1y side of the second piston 12y, there is an annular pressure side that opens and closes the pressure side passage 12by and allows only the flow of liquid passing through the pressure side passage 12by from the second pressure side chamber R2y toward the second expansion side chamber R1y. The check valves 17y are stacked one on top of the other. In this embodiment, the pressure side check valve 17y is composed of a valve body that is annular and movable in the axial direction with respect to the piston 12y, and a spring that biases the valve body toward the piston 12y. However, valves of other structures may also be used.

Continuing, the compression side damping force adjustment passage 23y provided in the piston rod 11y includes a compression side needle 24ay that is movably inserted into the piston rod 11y in the axial direction and can be seated and removed from the compression side annular valve seat 11b3y, and a compression side damping force adjustment passage 23y provided in the piston rod 11y. A compression-side damping force adjustment valve 24y is provided with a spring 24by that urges the needle 24ay in a direction to move away from the compression-side annular valve seat 11b3y. The compression needle 24ay includes a large diameter guide portion 24a1y that slides on the inner periphery of the lower end of the piston rod body 11ay, and a conical valve head 24a2y that extends downward from the guide portion 24a1y and seats on and off the compression side annular valve seat 11b3y. We are prepared. Therefore, the pressure side needle 24ay is guided by the guide portion 24a1y within the piston rod 11y and can move in the axial direction without axial wobbling.

The compression side damping force adjustment valve 24y can block the compression side damping force adjustment passage 23y when the compression side needle 24ay is seated on the compression side annular valve seat 11b3y, and when the compression side damping force adjustment valve 24y is moved back from the compression side annular valve seat 11b3y. 23y and by adjusting the size of the gap (flow path area) between the pressure side needle 24ay and the pressure side annular valve seat 11b3y, the resistance given to the flow of liquid passing through the pressure side damping force adjustment passage 23y can be adjusted. The outer periphery of the guide portion 24a1y is provided with a notch 24a3y, and since the guide portion 24a1y does not block the compression side damping force adjustment passage 23y, when the compression side damping force adjustment valve 24y is opened, the second Communication between the pressure side chamber R2y and the second reservoir Ry is ensured.

The flow path area in the pressure side damping force adjustment valve 24y is adjusted by operating the pressure side adjuster 25y housed in the inner periphery of the second cap 5y. The compression side adjuster 25y has a threaded portion on the outer periphery, and is rotatable in the circumferential direction on the inner periphery of the cylindrical spring adjuster 26y, which is rotatably mounted in the circumferential direction within the inner cylinder portion 5by of the second cap 5y. is inserted into. A feed screw mechanism is formed by the compression side adjuster 25y and the spring adjuster 26y, and when the compression side adjuster 25y is rotated with respect to the spring adjuster 26y, the compression side adjuster 25y moves in the vertical direction in FIG. 3 within the second cap 5y. . A cylindrical pressure-side control rod 30y is inserted between the compression-side adjuster 25y and the compression-side needle 24ay into the piston rod body 11ay so as to be movable in the axial direction in the vertical direction in FIG. 30y, vertical displacement of the compression side adjuster 25y is transmitted to the compression side needle 24ay. In this way, by operating the pressure side adjuster 25y provided on the second cap 5y at the upper end of the second front fork F2y, the flow path area of the compression side damping force adjustment valve 24y can be changed in size.

A threaded portion (not shown) is also formed on the outer periphery of the lower end of the spring adjuster 26y, and a nut 28y is attached to the threaded portion on the outer periphery of the spring adjuster 26y. The nut 28y includes a spring receiver 28ay that protrudes toward the outer circumferential side of the inner cylinder part 5by through the elongated hole 5cy of the inner cylinder part 5by of the second cap 5y. A suspension spring 29y is interposed between the spring receiver 28ay and the upper end of the case portion 15by of the rod guide 15y, and the suspension spring 29y biases the second fork body Fy to extend. A body B of a straddle-type vehicle V is elastically supported. When the spring adjuster 26y is rotated, the rotation of the nut 28y is restricted by the inner cylindrical portion 5by and moves in the vertical direction in FIG. 3, displacing the support position of the suspension spring 29y of the spring receiver 28ay in the vertical direction. The height of the straddle-type vehicle V can be adjusted.

The suspension system S is configured as described above, and the operation of the suspension system S will be explained below. First, when the first front fork F1x and the second front fork F2y in the suspension system S extend, the first damper Dx and the second damper Dy also extend. When the first damper Dx and the second damper Dy are expanded, the

pistons

12x and 12y move upward in the figure in the

cylinders

10x and 10y, reducing the expansion side chambers R1x and R1y and expanding the compression side chambers R2x and R2y. . Then, the liquid pushes open the expansion

side damping valves

16x, 16y of the

pistons

12x, 12y, passes through the expansion side damping passages 12ax, 12ay, and moves from the expansion side chambers R1x, R1y to the compression side chambers R2x, R2y. Since the growth

side damping valves

16x, 16y provide resistance to the flow of liquid passing through the growth side damping passages 12ax, 12ay, the pressure in the growth side chambers R1x, R1y increases.

In the first damper Dx, the growth-side damping force adjustment passage 20x is parallel to the growth-side damping passage 12ax and communicates the first growth-side chamber R1x with the first pressure-side chamber R2x. A growth-side damping force adjustment valve 21x is provided in the growth-side damping force adjustment passage 20x. Therefore, when the rebound damping force adjustment valve 21x is open, the liquid in the first rebound chamber R1x flows not only through the rebound damping passage 12ax but also through the rebound damping force adjustment passage 20x to the first pressure chamber R2x. Move to. Therefore, by adjusting the flow path area between the growth side damping force adjustment valve 21x and the growth side annular valve seat 11b4x in the growth side damping force adjustment valve 21x by operating the growth side adjuster 22x, the liquid passing through the growth side damping force adjustment passage 20x can be adjusted. The resistance given to the flow of the damper Dx can be adjusted, thereby making it possible to adjust the pressure within the first expansion side chamber R1x when the first damper Dx is expanded.

On the other hand, since the

piston rods

11x, 11y exit from the

cylinders

10x, 10y, there is a shortage of liquid in the expanding pressure side chambers R2x, R2y corresponding to the volume of the

piston rods

11x, 11y exiting from the

cylinders

10x, 10y. The expansion

side check valves

33x, 33y are opened and the liquid is supplied from the reservoirs Rx, Ry to the pressure side chambers R2x, R2y via the suction passages 13a2x, 13a2y. Therefore, the pressure in the pressure side chambers R2x, R2y becomes approximately equal to the pressure in the reservoirs Rx, Ry.

In this way, when the suspension system S is extended, the pressure in the extension side chambers R1x, R1y increases and becomes higher than the pressure in the compression side chambers R2x, R2y, which acts on the

pistons

12x, 12y, and the first damper Dx The second damper Dy generates a rebound damping force that prevents extension of the first front fork F1x, and the second damper Dy generates a rebound damping force that prevents extension of the second front fork F2y.

In the first damper Dx, the growth side damping force adjustment valve 21x adjusts the resistance given to the flow of liquid through the growth side damping force adjustment passage 20x from the first growth side chamber R1x to the first pressure side chamber R2x. It is possible to adjust the rebound damping force. Since the damping force that prevents the extension of the entire suspension system S is the sum of the damping forces generated by the first damper Dx and the second damper Dy, the first damper Dx in the first front fork F1x By adjusting the rebound damping force, the rebound damping force when the suspension system S is extended can be adjusted.

Continuing, when the first front fork F1x and the second front fork F2y in the suspension system S contract, the first damper Dx and the second damper Dy also contract. When the first damper Dx and the second damper Dy contract, the

pistons

12x, 12y move downward in the figure in the

cylinders

10x, 10y to contract the compression side chambers R2x, R2y and expand the expansion side chambers R1x, R1y. . Then, the liquid pushes open the pressure

side check valves

17x, 17y of the

pistons

12x, 12y, passes through the pressure side passages 12bx, 12by, and moves from the compression side chambers R2x, R2y to the growth side chambers R1x, R1y. Furthermore, since the

piston rods

11x and 11y enter the

cylinders

10x and 10y, the volume of liquid that the

piston rods

11x and 11y enter into the

cylinders

10x and 10y becomes excessive, and this excess liquid pushes open the

compression damping valves

32x, 32y and moves from the compression chambers R2x, R2y to the reservoirs Rx, Ry through the compression damping passages 13a1x, 13a1y. The pressure

side check valves

17x, 17y provide almost no resistance to the flow of liquid and make the pressure in the expansion side chambers R1x, R1y substantially equal to the pressure in the pressure side chambers R2x, R2y, while the compression

side damping valves

32x, 32y provide almost no resistance to the flow of liquid. Since resistance is provided to the flow of liquid passing through the damping passages 13a1x, 13a1y, the pressure within the

cylinders

10x, 10y increases.

In the second damper Dy, the compression side damping force adjustment passage 23y is parallel to the compression side damping passage 13a1y and communicates the second pressure side chamber R2y with the second reservoir Ry. A compression side damping force adjustment valve 24y is provided in the compression side damping force adjustment passage 23y. Therefore, in the state where the compression side damping force adjustment valve 24y is open, the liquid in the second pressure side chamber R2y moves to the second reservoir Ry not only through the compression side damping force adjustment passage 13a1y but also through the compression side damping force adjustment passage 23y. Therefore, by adjusting the flow path area between the compression side needle 24ay and the compression side annular valve seat 11b3y in the compression side damping force adjustment valve 24y by operating the compression side damping force adjustment valve 25y, the resistance given to the flow of liquid passing through the compression side damping force adjustment passage 23y can be reduced. can be adjusted, thereby making it possible to adjust the pressure inside the cylinder 10y when the second damper Dy is contracted.

In this way, when the suspension system S is contracted, the pressure in the expansion side chambers R1x, R1y and the pressure in the compression side chambers R2x, R2y rise approximately equally, and the pressure in the expansion side chambers R1x, R1y increases to the upper surface of the

pistons

12x, 12y. The pressure in the pressure side chambers R2x, R2y acts on the lower surfaces of the

pistons

12x, 12y, but since the

pistons

12x, 12y are connected to the

piston rods

11x, 11y, the pressure receiving area of the upper surfaces of the

pistons

12x, 12y Since the pressure-receiving area on the lower surface is larger, the first damper Dx generates a compression-side damping force that prevents the contraction of the first front fork F1x, and the second damper Dy generates a compression-side damping force that prevents the contraction of the second front fork F2y. occurs.

In the second damper Dy, the pressure-side damping force adjustment valve 24y adjusts the resistance that the pressure-side damping force adjustment passage 23y gives to the flow of liquid from the second pressure-side chamber R2y to the second reservoir Ry to generate a compression-side damping force. can be adjusted. Since the damping force that prevents the contraction of the entire suspension system S is the sum of the damping forces generated by the first damper Dx and the second damper Dy, the second damper Dy in the second front fork F2y By adjusting the compression side damping force, the compression side damping force when the suspension system S is contracted can be adjusted.

Therefore, in the suspension system S in this embodiment, the rebound damping force can be adjusted by operating the rebound adjuster 22x attached to the first cap 5x at the upper end of the first front fork F1x, and The compression side damping force can be adjusted by operating the compression side adjuster 25y attached to the second cap 5y at the upper end of the fork F2y.

As described above, the suspension system S of the present embodiment includes the first front fork F1x and the second front fork F2y that suspend the front wheel W of the straddle-type vehicle V from the vehicle body B, and the first front fork F1x is connected to the first vehicle body. A side tube 3x, a first axle side tube 4x that is movable in the axial direction with respect to the first vehicle body side tube 3x, a first cap 5x that closes the upper end of the first vehicle body side tube 3x, and a first axle side tube. a first fork body Fx that is extendable and retractable and has a first axle bracket 6x that closes the lower end of the front wheel 3x and holds the axle Ws of the front wheel W; a first cylinder 10x that is connected to the first axle bracket 6x; A first piston rod 11x that is inserted movably in the axial direction into the first cylinder 10x and whose upper end is connected to the first cap 5x; and a first piston rod 11x that is connected to the first piston rod 11x and inserted into the first cylinder 10x. It has a first piston 12x that divides the inside of the first cylinder 10x into a first expansion side chamber R1x filled with liquid and a first pressure side chamber R2x, and expands and contracts with the expansion and contraction of the first fork body Fx. and a first damper Dx that generates a damping force that prevents expansion and contraction of the first fork body Fx, and forms a first reservoir Rx that stores liquid in a space between the first fork body Fx and the first damper Dx. The second front fork F2y closes the upper end of the second body-side tube 3y, the second axle-side tube 4y that is movable in the axial direction with respect to the second body-side tube 3y, and the second body-side tube 3y. a second fork body Fy that is extendable and retractable, and a second axle bracket 6y that closes the lower end of the second axle side tube 4y and holds the axle Ws of the front wheel W; A second cylinder 10y connected to the bracket 6y, a second piston rod 11y inserted movably in the axial direction into the second cylinder 10y and connected at its upper end to the second cap 5y, and a second piston rod 11y. The second fork body Fy has a second piston 12y connected to the second cylinder 10y and inserted into the second cylinder 10y to partition the inside of the second cylinder 10y into a second expansion side chamber R1y and a second pressure side chamber R2y. and a second damper Dy that expands and contracts with the expansion and contraction of the second fork body Fy to generate a damping force that prevents the expansion and contraction of the second fork body Fy. The first damper Dx forms a second reservoir Ry for storage, and the first damper Dx connects a rebound damping force adjustment passage 20x that communicates the first rebound side chamber R1x and the first compression side chamber R2x, and a rebound side damping force adjustment passage 20x. The expansion side damping force adjustment valve 21x provided in the middle and the expansion side damping force adjustment valve 21x provided on the first cap 5x are expansion side damping force adjustment valves 21x that can adjust the resistance given to the flow of liquid passing through the expansion side damping force adjustment passage 20x. The second damper Dy has a compression side damping force adjustment passage 23y that communicates with the second compression side chamber R2y and the second reservoir Ry through the second piston rod 11y, and a compression side damping force adjustment passage 23y that communicates with the second compression side chamber R2y and the second reservoir Ry through the second piston rod 11y. The compression side damping force adjustment valve 24y provided in the middle of the force adjustment passage 23y and the compression side damping force adjustment valve 24y provided on the second cap 5y can adjust the resistance given to the flow of liquid passing through the compression side damping force adjustment passage 23y. It has a pressure side adjuster (compression side adjustment part) 25y.

In the suspension system S configured in this way, the first damper Dx of the first front fork F1x is capable of generating a damping force during expansion and contraction, and the expansion side adjuster (rebound side adjustment) that operates the expansion side damping force adjustment valve 21x ) can adjust the rebound damping force of the first damper Dx, and the second damper Dy in the second front fork F2y can generate damping force during expansion and contraction, and operates the compression damping force adjustment valve 24y. The compression side damping force of the second damper Dy can be adjusted by the compression side adjuster (compression side adjustment section) 25y. In the suspension system S configured in this way, a rebound adjuster (rebound adjustment section) 22x that operates the rebound damping force adjustment valve 21x is attached to the first cap 5x at the upper end of the first front fork F1x. A compression side adjuster (compression side adjustment section) 25y that operates the compression side damping force adjustment valve 24y is attached to the second cap 5y at the upper end of the second front fork F2y. Therefore, according to the suspension system S of this embodiment, the rebound damping force and the compression damping force can be adjusted at the upper ends of the first front fork F1x and the second front fork F2y.

In addition, in the suspension system S of this embodiment, the expansion side adjustment section is the expansion side adjuster 22x that can be manually operated by the user, and the compression side adjustment section is the compression side adjuster 25y that can be manually operated by the user. The user of the suspension system S can adjust the rebound damping force of the second front fork F2y by operating the rebound adjuster 22x at the upper end of the first front fork F1x while riding on the saddle type vehicle V. The compression side damping force can be adjusted by operating the compression side adjuster 25y at the upper end. Furthermore, in the suspension system S of this embodiment, the user does not have to take the trouble to get off the vehicle and bend down to adjust the rebound damping force and the compression damping force. Adjustment with damping force can be made easily.

In addition, in the suspension system S of the present embodiment, the first damper Dx and the second damper Dy both generate damping force when expanding and contracting, so the first damper Dx generates damping force only when expanding and contracting, and the first damper Dx generates a damping force only when expanding and contracting. The maximum pressure within the

cylinders

10x and 10y can be reduced compared to the case where the two dampers Dy generate damping force only during contraction. Therefore, according to the suspension system S of this embodiment, it is possible to reduce the weight of the parts that constitute the first damper Dx and the second damper Dy, and also to reduce costs.

In addition, as described above, the suspension system S includes the growth side adjuster 22x as a growth side adjustment section for adjusting the flow path area of the growth side damping force adjustment valve 21x, and the flow path area of the compression side damping force adjustment valve 24y. A compression-side adjuster 25y is provided as a compression-side adjustment section for adjustment of the rotation of the motor. A linear actuator or the like configured with a converting feed screw mechanism may also be used. In the suspension system S configured in this way, there is no need to place the linear actuator very close to the ground, and the linear actuator can be mounted on the upper ends of the first front fork F1x and the second front fork F2y. Wiring to the actuator can also be routed easily.

Furthermore, in the suspension system S of the present embodiment, as described above, the extension side damping force adjustment valve 21x is a needle valve, but it is provided on the piston rod 11x by displacement in the axial direction or in the circumferential direction. It may be a valve equipped with a shutter that opens and closes the port 11b3x. Furthermore, in the suspension system S of this embodiment, as described above, the compression side damping force adjustment valve 24y is a needle valve, but by displacement in the axial direction or in the circumferential direction, the horizontal damping force adjustment valve 24y provided on the piston rod 11y It may be a valve equipped with a shutter that opens and closes the hole 11a1y. The rebound side damping force adjustment valve 21x and the compression side damping force adjustment valve 24y include a valve body that can be seated on and off the annular valve seats 11b4x and 11b3y, and a spring that urges the valve body to sit on the annular valve seats 11b4x and 11b3y. It may be composed of. In this case, adjust the biasing force of the spring with the expansion side adjuster 22x, change the opening pressure of the expansion side damping force adjustment valve 21x, and adjust the resistance given to the flow of liquid passing through the expansion side damping force adjustment passage 20x. By adjusting the biasing force of the spring with the compression side adjuster 25y and changing the opening pressure of the compression side damping force adjustment valve 24y, it is possible to adjust the resistance given to the flow of liquid passing through the compression side damping force adjustment passage 23y. In this way, even if the rebound side damping force adjustment valve 21x and the compression side damping force adjustment valve 24y are changed to valves other than needle valves, the expansion side adjustment section and the compression side adjustment section can be replaced with the

adjusters

22x and 25y and used as linear actuators. good.

In addition, in the suspension system S of this embodiment, the compression side damping force adjustment passage 23y opens from the side of the second piston rod 11y and is connected to the horizontal hole 11a1y always facing the second reservoir Ry and the second piston rod 11y. It is formed by a vertical hole provided to communicate the second pressure side chamber R2y and the horizontal hole 11a1y, and the horizontal hole 11a1y is arranged below the liquid level Oy of the liquid in the second reservoir Ry. According to the suspension system S configured in this way, even if the second front fork F2y does not extend or contract for a long time, the horizontal hole 11a1y is always kept lower than the liquid level Oy regardless of the extension or contraction state of the second damper Dy. Since the damping force adjustment valve 24y is also arranged below, the liquid level within the compression damping force adjustment passage 23y does not fall below the compression side damping force adjustment valve 24y. If the liquid level in the compression side damping force adjustment passage 23y falls below the compression side damping force adjustment valve 24y, the second front fork F2y will exhibit an expansion and contraction action several times and the liquid level will decrease in the compression side damping force adjustment passage 23y. The compression side damping force cannot be adjusted until the liquid level rises and reaches the compression side damping force adjustment valve 24y. On the other hand, according to the suspension system S configured as described above, the compression side damping force adjustment valve 24y is always disposed in the liquid, and the liquid level in the compression side damping force adjustment passage 23y is lower than the pressure side damping force adjustment valve 24y. Therefore, the adjustment function of the compression damping force by the compression damping force adjustment valve 24y is not impaired when the second damper Dy is contracted. Note that even if the horizontal hole 11a1y is not always arranged below the liquid level Oy, the effect of the present invention of being able to easily adjust the rebound damping force and the compression damping force is not lost.

Furthermore, in the suspension system S of the present embodiment, the first piston rod 11x and the second piston rod 11y are both cylindrical, and the extension side damping force adjustment valve 21x is inserted into the first piston rod 11x in the axial direction. The compression side damping force adjustment valve 24y has a growth side needle 21ax that is movably inserted and a growth side annular valve seat 11b4x provided on the inner periphery of the first piston rod 11x, and the compression side damping force adjustment valve 24y is arranged in the second piston rod 11y in the axial direction. The first damper Dx is inserted into the first piston rod 11x and has a compression side annular valve seat 11b3y provided on the inner periphery of the second piston rod 11y. It has a growth side control rod 27x that transmits the movement of the adjuster (growth side adjustment part) 22x in the axial direction to the growth side needle, and the second damper Dy is inserted into the second piston rod 11y and the compression side adjuster ( It has a compression side control rod 30y that transmits the movement of the compression side adjustment section) 25y in the axial direction to the compression side needle 24ay, and the first damper Dx and the second damper Dy are connected to the first piston rod 11x, the second piston rod 11y, and the The components are the same except for the side needle 22ax, the compression side needle 24ay, the expansion side control rod 27x, and the compression side control rod 30y. According to the suspension system S configured in this way, the first damper Dx and the second damper Dy are the first piston rod 11x, the second piston rod 11y, the extension needle 22ax, the compression needle 24ay, and the extension control rod. 27x and the compression side control rod 30y, the number of parts can be kept to a minimum when manufacturing the first damper Dx and the second damper Dy, and the manufacturing cost of the suspension system S can be reduced. Furthermore, in the suspension system S of this embodiment, the first fork body Fx and the second fork body Fy are also made of the same parts, so that the manufacturing cost of the suspension system S can be further reduced.

In addition, in the second front fork F2y in the suspension system S of the embodiment described above, the horizontal hole 11a1y is always arranged below the liquid level Oy of the liquid in the second reservoir Ry with respect to the second piston rod 11y. The second damper Dy is installed in such a manner that there is no delay in the generation of damping force when the second damper Dy switches from extension to contraction. A check valve 34y that only allows the flow of liquid from the second pressure side chamber R2y toward the second reservoir Ry is installed in the middle of the compression side damping force adjustment passage 23y in series with the compression side damping force adjustment valve 24y to always keep the liquid in the second reservoir Ry. It may be installed so that it is arranged below the surface Oy.

The check valve 34y includes a flanged cylindrical valve seat 34ay, a spherical valve body 34by that can be seated on and off the valve seat 34ay, and a bottomed cylindrical shape attached to the outer periphery of the cylindrical portion of the valve seat 34ay. The valve body 34 includes a case 34cy having holes in the top and bottom, and a spring 34dy that is interposed between the case 34cy and the valve body 34by and urges the valve body 34by to sit on the valve seat 34ay. In this way, the check valve 34y is made into a cartridge, and is accommodated in the large diameter portion 11b1y of the center rod 11by that holds the piston 12y. The check valve 34y is fixed within the piston rod 11y by having the flange of the valve seat 34ay sandwiched between the tip of the piston rod body 11ay and the step between the large diameter portion 11b1y and the small diameter portion 11b2y of the center rod 11by. has been done. If the check valve 34y is made into a cartridge in this way, it can be easily installed inside the piston rod 11y. In addition, in this second damper D1y, since the check valve 34y is housed in the center rod 11by, as shown in FIG. , the second cap 5y is provided with a passage 40y that communicates between the second reservoir Ry and the inside of the piston rod 11y.

In the second damper Dy1 configured in this way, since the check valve 34y is disposed below the liquid level Oy, the check valve 34y prevents the liquid in the compression side damping force adjustment passage 23y from descending, and the pressure side damping is always maintained. The force adjustment valve 24y is now in the liquid. Therefore, according to the suspension system S in which the second damper Dy1 of the first modification is accommodated in the second front fork F2y, the adjustment function of the compression side damping force by the compression side damping force adjustment valve 24y is impaired when the second damper Dy1 is contracted. It never happens.

Regarding the arrangement of the compression side damping force adjustment valve 24y and the check valve 34y with respect to the compression side damping force adjustment passage 23y, in order to prevent a delay in the generation of damping force in the second damper Dy1, the compression side damping force adjustment valve 24y and the check valve 34y are are arranged in series, and it is sufficient that the check valve 34y is always arranged below the liquid level Oy of the second reservoir Ry.As long as these conditions are satisfied, the pressure side damping force adjustment valve 24y and the check valve 34y are arranged in series. The arrangement with the check valve 34y can be arbitrarily determined. Therefore, as shown in FIG. 4, a compression side damping force adjustment valve 24y is provided in the inner cylinder part 5by of the second cap 5y, and a structure is provided in which the second reservoir Ry and the inside of the piston rod 11y are communicated with the second cap 5y. Alternatively, as shown in FIG. 3, a compression side damping force adjustment valve 24y may be provided within the piston rod 11y. In addition, by housing the check valve 34y in the large diameter portion 11b1y that can secure space within the center rod 11by, the check valve 34y can be easily installed on the piston rod 11y, and even when the second damper D1y makes a full stroke. Since it does not come out of the cylinder 10y, the check valve 34y can be reliably placed below the liquid level Oy. Furthermore, if the check valve 34y is made into a cartridge as described above, it will be easier to install it in the second damper D1y, but the structure can be freely changed in design as long as it functions as a check valve.

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

3x...first vehicle body side tube, 3y...second vehicle body side tube, 4x...first axle side tube, 4y...second axle side tube, 5x...first cap, 5y... ...Second cap, 6x...First axle bracket, 6y...Second axle bracket, 10x...First cylinder, 10y...Second cylinder, 11x...First piston rod, 11b4x ...Rebound side annular valve seat, 11y...Second piston rod, 11a1y...Horizontal hole, 11b3y...Compression side annular valve seat, 12x...First piston, 12y...Second piston, 20x... Rebound damping amount adjustment passage, 21x... Rebound damping force adjustment valve, 21ax... Rebound side needle, 22x... Rebound side adjuster (growth side adjustment part), 23y... Compression side damping Force adjustment passage, 24y...Compression side damping force adjustment valve, 24ay...Compression side needle, 25y...Compression side adjuster (compression side adjustment part), 27x...Rebound side control rod, 30y...Compression side control rod, 34y...Check valve, B...Vehicle body, Dx...First damper, Dy, D1y...Second damper, F1x...First front fork, F2y...Second front fork, Fx ...First fork body, Fy...Second fork main body, O...Liquid level, S...Suspension device, Rx...First reservoir, Ry...Second reservoir, R1x...・First growth side chamber, R1y...Second growth side chamber, R2x...First pressure side chamber, R2y...Second pressure side chamber, V...Saddle type vehicle, W...Front wheel, Ws... ··axle

Claims

A suspension system having a first front fork and a second front fork for suspending a front wheel of a saddle type vehicle on a vehicle body,
The first front fork is
a first vehicle-side tube; a first axle-side tube that is movable in the axial direction with respect to the first vehicle-side tube; a first cap that closes an upper end of the first vehicle-side tube; an extendable first fork body having a first axle bracket that closes the lower end of the tube and holds the axle of the front wheel;
a first cylinder connected to the first axle bracket; a first piston rod that is movably inserted in the first cylinder in the axial direction and whose upper end is connected to the first cap; and the first piston. a first piston connected to the rod and inserted into the first cylinder to partition the inside of the first cylinder into a first expansion side chamber and a first compression side chamber; a first damper that expands and contracts as the first fork body expands and contracts to generate a damping force that prevents expansion and contraction of the first fork body;
A first reservoir for storing liquid is formed in a space between the first fork body and the first damper,
The second front fork is
a second vehicle-side tube; a second axle-side tube that is movable in the axial direction with respect to the second vehicle-side tube; a second cap that closes an upper end of the second vehicle-side tube; and a second cap that closes the upper end of the second vehicle-side tube; an extendable second fork body having a second axle bracket that closes the lower end of the tube and holds the axle of the front wheel;
a second cylinder connected to the second axle bracket; a second piston rod that is movably inserted into the second cylinder in the axial direction and whose upper end is connected to the second cap; and the second piston. a second piston connected to the rod and inserted into the second cylinder to partition the inside of the second cylinder into a second expansion side chamber and a second pressure side chamber; a second damper that generates a damping force that expands and contracts with the movement of the second fork body and prevents expansion and contraction of the second fork body;
A second reservoir for storing liquid is formed in a space between the second fork body and the second damper,
The first damper includes a growth side damping force adjustment passage that communicates the first growth side chamber and the first compression side chamber, a growth side damping force adjustment valve provided in the middle of the growth side damping force adjustment passage; a rebound adjustment section provided in the first cap and capable of adjusting the resistance that the rebound damping force adjustment valve gives to the flow of liquid passing through the rebound damping force adjustment passage;
The second damper includes a compression damping force adjustment passage that communicates with the second pressure chamber and the second reservoir through the second piston rod, and a compression damping force adjustment valve provided in the middle of the compression damping force adjustment passage. , a compression side adjustment part provided in the second cap and capable of adjusting the resistance that the compression side damping force adjustment valve gives to the flow of liquid passing through the compression side damping force adjustment passage.
The suspension device according to claim 1,
The compression side damping force adjustment passage includes a horizontal hole that opens from the side of the second piston rod and always faces the second reservoir, and a horizontal hole that is provided in the second piston rod and that connects the second pressure side chamber and the horizontal hole. It is formed by a vertical hole that communicates with the
The horizontal hole is arranged below the liquid level of the liquid in the second reservoir.
The suspension device according to claim 1,
The compression side damping force adjustment passage includes a horizontal hole that opens from the side of the second piston rod and always faces the second reservoir, and a horizontal hole that is provided in the second piston rod and that connects the second pressure side chamber and the horizontal hole. It is formed by a vertical hole that communicates with the
The second damper includes a check valve that is provided in series with the compression damping force adjustment valve in the middle of the compression damping force adjustment passage and allows only the flow of liquid from the second pressure side chamber toward the second reservoir. death,
The check valve is disposed below the liquid level of the liquid in the second reservoir.
The suspension device according to claim 1,
The first piston rod and the second piston rod are both cylindrical,
The expansion side damping force adjustment valve has a growth side needle that is movably inserted in the first piston rod in the axial direction, and a growth side annular valve seat provided on the inner periphery of the first piston rod,
The compression side damping force adjustment valve has a compression side needle that is movably inserted in the second piston rod in the axial direction, and a compression side annular valve seat provided on the inner periphery of the second piston rod,
The first damper has a growth side control rod that is inserted into the first piston rod and transmits the power of the growth side adjustment section to the growth side needle,
The second damper includes a pressure side control rod that is inserted into the second piston rod and transmits the power of the pressure side adjustment section to the compression side needle,
The first damper and the second damper have common components except for the first piston rod, the second piston rod, the extension needle, the compression needle, the extension control rod, and the compression control rod. Has a suspension system.