Suspension device

Abstract

A suspension device (S) is provided with a first front fork (F1x) having an extension-side adjustment section (22x) which is provided on a first cover (5x) for closing the upper end of a first vehicle-body-side pipe (3x) and which is capable of adjusting the resistance applied by an extension-side damping force adjustment valve (21x) to the flow of liquid flowing through an extension-side damping force adjustment channel (20x), and a second front fork (F2y) having a compression-side adjustment section (25y) which is capable of adjusting the resistance applied by an extension-side damping force adjustment valve (21x) to the flow of liquid flowing through an extension-side damping force adjustment channel (20x). And a second cover (5y) for closing the upper end of the second vehicle-body-side pipe (3y), said second cover (5y) being capable of adjusting the resistance applied by the compression-side damping force adjustment valve (24y) to the flow of liquid flowing through the compression-side damping force adjustment passage (23y).

Description

Technical Field

[0001] The invention relates to a suspension device. Background Art

[0002] Conventionally, a suspension device interposed between a vehicle body and a front wheel of a suspension straddle-type vehicle is structured to include a pair of left and right front forks, each of which has a shock absorber built in.

[0003] More specifically, each front fork includes a fork body and a shock absorber housed in the fork body, wherein the fork body includes a body side tube, an axle side tube capable of axially moving relative to the body side tube, a cover for closing the upper end of the body side tube, and an axle bracket for closing the lower end of the axle side tube and holding the axle of the front wheel.

[0004] In addition, the shock absorber comprises: a cylinder whose lower end is fixed to the axle bracket; a piston rod connected to the cover at the upper end and inserted into the cylinder; a piston, which is mounted on the front end of the piston rod and can be freely slidably inserted into the cylinder to divide the interior of the cylinder into an extension side chamber and a compression side chamber; a valve disc, which is inserted into the lower part of the cylinder and separates the chamber connected to the liquid storage chamber outside the cylinder from the compression side chamber through a hole provided on the cylinder; an extension side port and a compression side port provided on the piston; an extension side leaf valve, which is used to control the extension of the liquid from the extension side port A switch to apply resistance to the flow of liquid from the extension side chamber to the compression side chamber; a compression side check valve, which is used to switch the compression side port to only allow liquid to flow from the compression side chamber to the extension side chamber; a compression side damping port and a suction port arranged on the valve disc; a compression side leaf valve, which is used to switch the compression side damping port to apply resistance to the flow of liquid from the compression side chamber to the liquid storage chamber; an extension side check valve, which is used to switch the suction port to only allow liquid to flow from the liquid storage chamber to the compression side chamber.

[0005] As disclosed in Japanese patent JPH11-201214A or JPH06-56532U, in a suspension device, in order to be able to adjust the damping force generated by the shock absorbers in the left and right front forks, the shock absorbers, in addition to the above-mentioned structure, also have: an extension side damping force adjustment channel that bypasses the extension side port on the piston rod and connects the extension side chamber and the compression side chamber; an extension side needle valve arranged in the middle of the extension side damping force adjustment channel; a compression side damping force adjustment channel arranged on the axle bracket for connecting the compression side chamber and the liquid storage chamber; a compression side needle valve arranged in the middle of the compression side damping force adjustment channel. In the suspension device constructed in this manner, the flow path area of ​​the extension-side needle valve can be adjusted by operating the extension-side adjuster set on the cover of the fork body to adjust the extension-side damping force when the shock absorber is extended. At the same time, the flow path area of ​​the compression-side needle valve can be adjusted by operating the compression-side adjuster set on the axle bracket to adjust the compression-side damping force when the shock absorber is contracted. Prior art literature Patent Literature

[0006] Patent Document 1: Japanese Patent JPH11-201214A Patent Document 2: Japanese Patent JPH06-56532U Summary of the invention Problems to be solved by the invention

[0007] In the conventional suspension device, the extension side damping force and the compression side damping force of the shock absorber on each front fork can be adjusted independently. Since the compression side adjuster is provided on the axle bracket at the lower end of the front fork, the user needs to get off the vehicle and bend over to operate the compression side adjuster in order to adjust the compression side damping force. Thus, in the conventional suspension device, the adjustment of the compression side damping force is a very troublesome task. Therefore, a suspension device is required in which not only the extension side damping force but also the compression side damping force can be adjusted on the upper end side of the front fork.

[0008] Furthermore, considering that the compression-side damping force is adjusted by the actuator, in the conventional suspension device, the actuator is arranged at a position close to the ground, and therefore, it is not appropriate to provide the actuator in the conventional suspension device.

[0009] Therefore, an object of the present invention is to provide a suspension device capable of adjusting the extension-side damping force and the compression-side damping force at the upper end side of a front fork. Solutions to Solve Problems

[0010] In order to solve the above problems, the suspension device of the present invention has a first front fork and a second front fork for suspending the front wheel of the suspension straddle type vehicle on the vehicle body. The first front fork has: a telescopic first fork body having a first vehicle body side tube, a first axle side tube that can move in the axial direction relative to the first vehicle body side tube, a first cover for closing the upper end of the first vehicle body side tube, and a first axle bracket for closing the lower end of the first axle side tube and for holding the axle of the front wheel; a first shock absorber having a first cylinder connected to the first axle bracket, a first piston rod that can be inserted into the first cylinder movably in the axial direction and whose upper end is connected to the first cover, and a first piston connected to the first piston rod and inserted into the first cylinder to divide the inside of the first cylinder into a first extension side chamber and a first compression side chamber, and the first shock absorber is extended and retracted with the extension and retraction of the first fork body, and generates a damping force for hindering the extension and retraction of the first fork body. A first liquid storage chamber for storing liquid is formed in the space between the first fork body and the first shock absorber. The second front fork includes: a telescopic second fork body having a second body side tube, a second axle side tube that can move in the axial direction relative to the second body side tube, a second cover for closing the upper end of the second body side tube, and a second axle bracket for closing the lower end of the second axle side tube and holding the axle of the front wheel; a second shock absorber having a second cylinder connected to the second axle bracket, a second piston rod that can be inserted into the second cylinder movably in the axial direction and whose upper end is connected to the second cover, and a second piston that is connected to the second piston rod and inserted into the second cylinder and divides the interior of the second cylinder into a second extension side chamber and a second compression side chamber, the second shock absorber is extended and retracted along with the extension and retraction of the second fork body to generate a damping force for hindering the extension and retraction of the second fork body. A second liquid storage chamber for storing liquid is formed in a space between the second fork body and the second shock absorber. The first shock absorber has an extension-side damping force adjustment passage for connecting the first extension-side chamber and the first compression-side chamber, an extension-side damping force adjustment valve disposed in the middle of the extension-side damping force adjustment passage, and an extension-side adjustment portion disposed on the first cover and capable of adjusting the resistance applied by the extension-side damping force adjustment valve to the flow of liquid flowing through the extension-side damping force adjustment passage. The second shock absorber has a compression-side damping force adjustment passage passing through the second piston rod and for connecting the second compression-side chamber and the second liquid storage chamber, a compression-side damping force adjustment valve disposed in the middle of the compression-side damping force adjustment passage, and a compression-side adjustment portion disposed on the second cover and capable of adjusting the resistance applied by the compression-side damping force adjustment valve to the flow of liquid flowing through the compression-side damping force adjustment passage. According to the suspension device thus constructed, the extension-side damping force and the compression-side damping force can be adjusted at the upper ends of the first front fork and the second front fork. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a front view of a suspension straddle-type vehicle to which a suspension device according to an embodiment of the present invention is applied. Figure 2 It is a cross-sectional view of a first front fork of a suspension device according to an embodiment of the present invention. Figure 3 It is a cross-sectional view of a second front fork of the suspension device according to one embodiment of the present invention. Figure 4 It is a cross-sectional view of a second front fork according to a modified example for accommodating the second shock absorber. DETAILED DESCRIPTION

[0012] The present invention will be described below based on the embodiments shown in the drawings. Figure 1 As shown, a suspension device S according to one embodiment includes a first front fork F1x and a second front fork F2y, and suspends a front wheel W on a vehicle body B of a suspended straddle-type vehicle V such as a motorcycle or a tricycle.

[0013] Next, each part of the suspension device S will be described in detail. In addition, the first front fork F1x and the second front fork F2y have a plurality of common parts, and when describing each part of the first front fork F1x and the second front fork F2y, in this specification, when "first" and "second" are not marked before the name of the component, unless otherwise specified, all of them refer to the components of both the first front fork F1x and the second front fork F2y. In addition, in this specification, if x is marked at the end of the symbol of a component, it means that it is a component of the first front fork F1x, and if y is marked at the end of the symbol of a component, it means that it is a component of the second front fork F2y.

[0014] like Figure 1 As shown, the suspension device S includes a first front fork F1x, a second front fork F2y, and a pair of upper and lower brackets 1 and 2 for holding the upper ends of the first front fork F1x and the second front fork F2y. The brackets 1 and 2 are mounted on a steering shaft that is rotatably inserted into a head pipe P provided at the front end of a vehicle body B of a suspension straddle type vehicle V, and are rotatably connected to the vehicle body B along the circumferential direction of the head pipe P. The upper end sides of the first front fork F1x and the second front fork F2 are held by the brackets 1 and 2 that are rotatably connected to the head pipe P relative to the vehicle body B, and the axle Ws of the front wheel W is connected to the lower end. In this way, the suspension device S suspends the front wheel W relative to the vehicle body B of the suspension straddle type vehicle V through the pair of left and right front forks F1x and F2y.

[0015] like Figure 2As shown, the first front fork F1x includes a telescopic first fork body Fx and a first shock absorber Dx housed in the first fork body Fx, wherein the telescopic first fork body Fx includes a first vehicle body side tube 3x, a first axle side tube 4x that can move in the axial direction relative to the first vehicle body side tube 3x, a first cover 5x for closing the upper end of the first vehicle body side tube 3x, and a first axle bracket 6x for closing the lower end of the first axle side tube 3x and holding the axle Ws of the front wheel W. In addition, as shown Figure 3 As shown, the second front fork F2y has a telescopic second fork body Fy and a second shock absorber Dy housed in the second fork body Fy, wherein the second fork body Fy has a second body side tube 3y, a second axle side tube 4y capable of axially moving relative to the second body side tube 3y, a second cover 5y for closing the upper end of the second body side tube 3y, and a second axle bracket 6y for closing the lower end of the second axle side tube 4y and holding the axle Ws of the front wheel W.

[0016] like Figure 2 and Figure 3 As shown in the figure, a cover 5x, 5y is mounted on the open end of the upper end of the body side tube 3x, 3y, and the upper end of the body side tube 3x, 3y is closed by the cover 5x, 5y. The cover 5x, 5y has an annular outer ring portion 5ax, 5ay screwed with the inner circumference of the upper end of the body side tube 3x, 3y, and an inner cylinder portion 5bx, 5by protruding downward from the inner circumference of the outer ring portion 5ax, 5ay and screwed with the upper end of the piston rod 11x, 11y described later. In addition, a pair of long holes 5cx, 5cy are provided on the inner cylinder portion 5bx, 5by of the cover 5x, 5y, which are radially opposed to each other and along the axial direction of the inner cylinder portion 5bx, 5by.

[0017] The axle side tubes 4x and 4y are inserted into the body side tubes 3x and 3y from below and can move relative to the body side tubes 3x and 3y in the axial direction. In addition, annular sleeves 7x and 7y and annular sealing members 8x and 8y are provided on the inner periphery of the lower end of the body side tubes 3x and 3y so as to be in sliding contact with the outer periphery of the axle side tubes 4x and 4y, and annular sleeves 9x and 9y are installed on the outer periphery of the upper end of the axle side tubes 4x and 4y so as to be in sliding contact with the inner periphery of the body side tubes 3x and 3y. Therefore, the body side tubes 3x and 3y and the axle side tubes 4x and 4y can move relative to each other in the axial direction without axial vibration through the sleeves 7x, 7y, 9x and 9y.

[0018] The lower ends of the axle side tubes 4x and 4y are closed by axle brackets 6x and 6y that hold the axle Ws of the front wheel W, and the fork bodies Fx and Fy are connected to the front wheel W through the axle brackets 6x and 6y. And the interior of the fork bodies Fx and Fy thus constructed becomes a space that is sealed from the outside by the sealing components 8x and 8y. The axle brackets 6x and 6y have a cylindrical portion 6ax and 6ay that is cylindrical and threadedly connected to the outer periphery of the lower ends of the axle side tubes 4x and 4y, and a gripping portion 6bx and 6by that is connected to the bottom of the cylindrical portion 6ax and 6ay and holds the axle Ws. In addition, although not shown in the figure, a mounting portion that can mount a brake caliper, a fender, etc. is provided on the axle brackets 6x and 6y.

[0019] The first shock absorber Dx includes a first cylinder 10x connected to the first axle bracket 6x, a first piston rod 11x inserted into the first cylinder 10x movably in the axial direction and connected to the first cover 5x at its upper end, and a first piston 12x connected to the first piston rod 11x and inserted into the first cylinder 10x, dividing the interior of the first cylinder 10x into a first expansion side chamber R1x and a first compression side chamber R2x filled with liquid. The first shock absorber expands and contracts with the expansion and contraction of the first fork body Fx, and generates a damping force for hindering the expansion and contraction of the first fork body Fx. In this way, when the first shock absorber Dx is accommodated in the first fork body Fx, a liquid storage chamber Rx for storing liquid is formed outside the first shock absorber Dx and inside the first fork body Fx. Furthermore, the first shock absorber Dx has an extension side damping force adjustment channel 20x for connecting the first extension side chamber R1x and the first compression side chamber R2x, an extension side damping force adjustment valve 21x arranged in the middle of the extension side damping force adjustment channel 20x, and an extension side adjuster 22x arranged on the first cover 5x and serving as an extension side adjustment part capable of adjusting the resistance applied by the extension side damping force adjustment valve 21x to the flow of liquid flowing through the extension side damping force adjustment channel 20x.

[0020] The second shock absorber Dy includes a second cylinder 10y connected to the second axle bracket 6y, a second piston rod 11y inserted into the second cylinder 10y in an axially movable manner and connected to the second cover 5y at its upper end, and a second piston 12y connected to the second piston rod 11y and inserted into the second cylinder 10y to divide the interior of the second cylinder 10y into a second expansion side chamber R1y filled with liquid and a second compression side chamber R2y. The second shock absorber Dy contracts and expands as the second fork body Fy expands and contracts, and generates a damping force that hinders the expansion and contraction of the second fork body Fy. In this way, when the second shock absorber Dy is accommodated in the second fork body Fy, a second liquid storage chamber Ry for storing liquid is formed outside the second shock absorber Dy and inside the second fork body Fy. Furthermore, the second shock absorber Dy has: a compression side damping force adjusting channel 23y, which passes through the second piston rod 11y and is located in the second compression side chamber R2y and the second fork body Fy and is connected to the outside of the second cylinder 10y; a compression side damping force adjusting valve 24y, which is arranged in the middle of the compression side damping force adjusting channel 23y; a compression side adjuster 25y, which serves as a compression side adjusting part and is arranged in the second cover 5y, and can adjust the resistance applied by the compression side damping force adjusting valve 24y to the flow of liquid flowing through the compression side damping force adjusting channel 23y.

[0021] Next, the components constituting the first shock absorber Dx and the second shock absorber Dy are described. The cylinders 10x and 10y are connected to the axle brackets 6x and 6y through the bottom valve assemblies 13x and 13y fixed to the axle brackets 6x and 6y of the fork bodies Fx and Fy. The cylinders 10x and 10y have through holes 10ax and 10ay that are opened at the side of the lower end and communicate with the inside of the cylinders 10x and 10y and the reservoirs Rx and Ry. In addition, annular rod guides 15x and 15y are attached to the upper open ends of the cylinders 10x and 10y. The rod guides 15x and 15y are annular and screwed with the inner circumference of the upper end of the cylinder 10x and 10y to be inserted into the inner circumference and slide in contact with the outer circumference of the piston rod 11x and 11y, and cylindrical housing parts 15bx and 15by protruding upward from the upper end of the guide parts 15ax and 15ay. In the suspension device S of the present embodiment, the liquid filled in the cylinder 10x and 10y and the reservoir Rx and Ry is hydraulic oil, but it may be a liquid other than hydraulic oil.

[0022] The bottom valve assembly 13x, 13y includes: an annular partition 13ax, 13ay, which is embedded in the upper side of the through hole 10ax, 10ay of the cylinder 10x, 10y; a retaining component 13bx, 13by, which is fixed to the axle bracket 6x, 6y by bolts 14x, 14y that pass through the bottom of the cylindrical portion 6ax, 6ay of the axle bracket 6x, 6y, and is threaded with the lower end of the cylinder 10x, 10y to retain the partition 13ax, 13ay. The holding members 13bx and 13by have a closing portion 13b1x and 13b1y which is screwed on the inner circumference of the lower end of the cylinder 10x and 10y below the through holes 10ax and 10ay to close the lower end of the cylinder 10x and 10y, and a shaft portion 13b2x and 13b2y which protrudes upward from the closing portion 13b1x and 13b1y and has a partition 13ax and 13ay installed on the outer circumference. In this way, the space between the partition 13ax and 13ay and the closing portion 13b1x and 13b1y in the cylinder 10x and 10y is connected to the liquid storage chamber Rx and Ry through the through holes 10ax and 10ay, and the partition 13ax and 13ay divide the inside of the cylinder 10x and 10y into the compression side chamber R2x and R2y and the space connected to the liquid storage chamber Rx and Ry.

[0023] In addition, the partition bodies 13ax and 13ay are provided with compression side damping passages 13a1x and 13a1y and suction passages 13a2x and 13a2y for connecting the compression side chambers R2x and R2y with the space. Moreover, the compression side damping passages 13a1x and 13a1y are provided with compression side damping valves 32x and 32y for applying resistance to the flow of liquid from the compression side chambers R2x and R2y to the liquid storage chambers Rx and Ry. The suction passages 13a2x and 13a2y are provided with extension side check valves 33x and 33y for allowing only the liquid to flow from the liquid storage chambers Rx and Ry to the compression side chambers R2x and R2y.

[0024] The piston rods 11x and 11y have a cylindrical piston rod body 11ax and 11ay and a cylindrical center rod 11bx and 11by connected to the lower end of the piston rod body 11ax and 11ay and used to hold the piston 12x and 12y. In addition, the upper ends of the piston rods 11x and 11y are connected to the inner cylinders 5bx and 5by of the caps 5x and 5y by screwing, and the lower ends are inserted into the cylinders 10x and 10y through the inner circumference of the rod guides 15x and 15y. The piston rods 11x and 11y can move relative to the pistons 12x and 12y in the axial direction (up and down direction in the figure) while being restricted from moving radially relative to the cylinders 10x and 10y by the rod guides 15x and 15y and the pistons 12x and 12y.

[0025] like Figure 2As shown, the center rod 11bx of the first piston rod 11x is cylindrical and has: a large diameter portion 11b1x, which is screwed with the outer periphery of the lower end of the piston rod body 11ax; a small diameter portion 11b2x, whose outer diameter is smaller than that of the large diameter portion 11b1x and on which the piston 12x is mounted; a port 11b3x, which is provided at the large diameter portion 11b1x and penetrates the large diameter portion 11b1x in the radial direction; and an extension side annular valve seat 11b4x, which is formed by a step portion provided on the inner periphery closer to the small diameter portion 11b2x side than the port 11b3x. An annular locking block 31x is provided on the outer periphery of the piston rod body 11ax, which enters into the housing portion 15bx of the rod guide 15x when the first shock absorber Dx is contracted to the limit. When the locking block 31x enters into the housing portion 15bx, the pressure in the housing portion 15bx is increased to suppress further contraction of the first shock absorber Dx.

[0026] In addition, the center rod 11bx is cylindrical, and since the opening at the front end of the center rod 11bx faces the first compression side chamber R2x, the first extension side chamber R1x and the first compression side chamber R2x are connected through the interior of the center rod 11bx and the port 11b3x. In this way, an extension side damping force adjustment channel 20x is formed inside the piston rod 11x.

[0027] The first piston 12x has an annular expansion-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, and is fitted to the outer periphery of the small-diameter portion 11b2x of the center rod 11bx.

[0028] An annular extension-side damping valve 16x is provided on the first compression-side chamber R2x side of the first piston 12x, which is used to open or close the extension-side damping passage 12ax and to apply resistance to the flow of liquid passing through the extension-side damping passage 12ax from the first extension-side chamber R1x to the first compression-side chamber R2x. In the present embodiment, the extension-side damping valve 16x is a leaf valve whose inner periphery is fixed to the center rod 11bx and whose outer periphery is allowed to bend, but it may also be a valve other than a leaf valve, and the design of the number of lamination layers of the leaf valve may also be changed.

[0029] An annular compression-side check valve 17x is overlapped on the first extension-side chamber R1x side of the first piston 12x. The compression-side check valve only allows the flow of liquid from the first compression-side chamber R2x to the first extension-side chamber R1x through the compression-side passage 12bx while opening or closing the compression-side passage 12bx. In the present embodiment, the compression-side check valve 17x is composed of an annular valve body that can move axially relative to the piston 12x and a spring that applies force to the valve body in the direction of the piston 12x, but it may also be a valve of other structures.

[0030] Next, an extension side damping force regulating valve 21x is provided on the extension side damping force regulating passage 20x provided in the piston rod 11x, and the extension side damping force regulating valve comprises: an extension side needle 21ax which is inserted into the piston rod 11x movably along the axial direction and can be seated on the extension side annular valve seat 11b4x; a spring 21bx which applies a force to the extension side needle 21ax in a direction to make it leave the extension side annular valve seat 11b4x. The extension side needle 21ax comprises: a large diameter guide portion 21a1x which is in sliding contact with the inner periphery of the lower end of the piston rod body 11ax; a conical valve head 21a2x which extends downward from the guide portion 21a1x and can be seated on the extension side annular valve seat 11b4x; and a sealing ring 21a3x which is mounted on the outer periphery of the guide portion 21a1x and is in sliding contact with the inner periphery of the piston rod body 11ax. Therefore, the extension needle 21ax can be guided by the guide portion 21a1x in the piston rod 11x and can move in the axial direction without axial vibration, and the seal ring 21a3x prevents the liquid from passing over the guide portion 21a1x and moving upward in the piston rod 11x.

[0031] If the extension side damping force regulating valve 21x makes the extension side needle 21ax sit on the extension side annular valve seat 11b4x, the extension side damping force regulating channel 20x can be cut off, and when the extension side needle 21ax is withdrawn from the extension side annular valve seat 11b4x, the extension side damping force regulating channel 20x is opened, and by adjusting the size of the gap (flow path area) between the extension side needle 21ax and the extension side annular valve seat 11b4x, the resistance applied to the flow of liquid flowing through the extension side damping force regulating channel 20x can be adjusted.

[0032] The flow path area of ​​the extension-side damping force regulating valve 21x can be adjusted by operating the extension-side adjuster 22x housed in the inner circumference of the first cover 5x. The extension-side adjuster 22x has a threaded portion on the outer circumference, and is rotatably inserted into the inner circumference of a cylindrical spring adjuster 26x in the circumferential direction. The spring adjuster is rotatably installed in the inner cylinder portion 5bx of the first cover 5x in the circumferential direction. The feed screw mechanism is formed by the extension-side adjuster 22x and the spring adjuster 26x. If the extension-side adjuster 22x is rotated relative to the spring adjuster 26x, the extension-side adjuster 22x is rotated in the first cover 5x. Figure 2 Between the extension side adjuster 22x and the extension side needle 21ax, the cylindrical extension side control rod 27x is axially ( Figure 2The extension side adjuster 22x is inserted into the piston rod body 11ax movably (in the vertical direction in the extension side), and the vertical displacement of the extension side adjuster 22x is transmitted to the extension side needle 21ax through the extension side control rod 27x. In this way, by operating the extension side adjuster 22x provided on the first cover 5x at the upper end of the first front fork F1x, the size of the flow path area of ​​the extension side damping force regulating valve 21x can be changed.

[0033] In addition, 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 installed on the threaded portion of the outer periphery of the spring adjuster 26x. The nut 28x has a spring seat 28ax that protrudes toward the outer periphery of the inner cylinder portion 5bx through the long hole 5cx of the inner cylinder portion 5bx of the first cover 5x. Moreover, a suspension spring 29x is sandwiched between the spring seat 28ax and the upper end of the shell portion 15bx of the rod guide 15x, and the suspension spring 29x applies force in a manner to extend the first fork body Fx, thereby elastically supporting the body B of the suspension straddle type vehicle V. When the spring adjuster 26x is rotated, since the nut 28x is restricted from rotating by the inner cylinder portion 5bx, the nut 28x is rotated. Figure 2 The vertical movement causes the support position of the suspension spring 29x of the spring seat 28ax to be displaced in the vertical direction, so that the vehicle height of the suspension straddle type vehicle V can be adjusted.

[0034] On the other hand, Figure 3 As shown, the piston rod body 11ay of the second piston rod 11y has a transverse hole 11a1y. Although the piston rod body 11ax of the first piston rod 11x does not have a transverse hole, the piston rod body 11ay of the second piston rod 11y has a transverse hole 11a1y. In this respect, the structures of the piston rod body 11ax and the piston rod body 11ay are different. Even if the second shock absorber Dy is contracted to the maximum limit and the piston rod 11y enters the cylinder 10y to the maximum extent, the transverse hole 11a1y is located above the housing portion 15by and is connected to the second fluid storage chamber Ry. In this way, the transverse hole 11a1y is always connected to the second fluid storage chamber Ry. Furthermore, even if the second shock absorber Dy is extended to the limit and the piston rod 11y is extended to the maximum extent from the cylinder 10y Figure 3 The horizontal hole 11a1y can also always be moved upward and downward, and is set at a position lower than the liquid level Oy of the liquid stored in the second liquid storage chamber Ry.

[0035] In addition, an annular locking block 31y is provided on the outer periphery of the piston rod body 11ay and at a position lower than the transverse hole 11a1y. The locking block 31y enters into the housing portion 15by of the rod guide 15y when the second shock absorber Dy contracts to the limit. When the locking block 31y enters into the housing portion 15by, the pressure in the housing portion 15by increases to suppress further contraction of the second shock absorber Dy.

[0036] In addition, the center rod 11by of the second piston rod 11y is cylindrical and has: a large diameter portion 11b1y, which is screwed with the outer periphery of the lower end of the piston rod body 11ay; a small diameter portion 11b2y, whose outer diameter is smaller than that of the large diameter portion 11b1y and on which the piston 12y is installed; and a compression side annular valve seat 11b3y, which is formed by a step portion provided on the inner periphery. Although the center rod 11bx of the first piston rod 11x has a port 11b3x, the center rod 11by of the second piston rod 11y does not have a port, and in this respect, the structures of the center rod 11bx and the center rod 11by are different.

[0037] In addition, the piston rod body 11ay and the center rod 11by are cylindrical, and since the opening at the front end of the center rod 11by faces the second compression side chamber R2y, the second compression side chamber R2y is connected to the liquid storage chamber Ry through the inside of the second piston rod 11y and the transverse hole 11a1y. In this way, by making the second piston rod 11y cylindrical and forming a vertical hole that connects the transverse hole 11a1y and the second compression side chamber R2y, a compression side damping force adjustment channel 23y is formed inside the second piston rod 11y.

[0038] The second piston 12y has an annular expansion-side damping passage 12ay and a compression-side passage 12by which connect the second expansion-side chamber R1y and the second compression-side chamber R2y in parallel, and is fitted to the outer periphery of the small-diameter portion 11b2y of the center rod 11by.

[0039] An annular extension side damping valve 16y is provided on the second compression side chamber R2y side of the second piston 12y for opening or closing the extension side damping passage 12ay and applying resistance to the flow of the liquid flowing from the second extension side chamber R1y to the second compression side chamber R2y through the extension side damping passage 12ay. In the present embodiment, the extension 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 also be a valve other than a leaf valve, and the design of the number of lamination layers of the leaf valve may also be changed.

[0040] An annular compression side check valve 17y is overlapped on the second extension side chamber R1y side of the second piston 12y. The compression side check valve can only allow liquid to flow from the second compression side chamber R2y to the second extension side chamber R1y through the compression side channel 12by while opening or closing the compression side channel 12by. In the present embodiment, the compression side check valve 17y is composed of an annular valve body that can move axially relative to the piston 12y and a spring that urges the valve body toward the piston 12y, but it can also be a valve of other structures.

[0041] Next, a compression side damping force regulating valve 24y is provided on the compression side damping force regulating passage 23y provided in the piston rod 11y, and the compression side damping force regulating valve includes: a compression side needle 24ay which is inserted into the piston rod 11y movably along the axial direction and can be seated on the compression side annular valve seat 11b3y; and a spring 24by which applies a force to the compression side needle 24ay in a direction to make it leave the compression side annular valve seat 11b3y. The compression side needle 24ay includes: a large diameter guide portion 24a1y which is in sliding contact with the inner periphery of the lower end of the piston rod body 11ay; and a conical valve head 24a2y which extends downward from the guide portion 24a1y and can be seated on the compression side annular valve seat 11b3y. Therefore, the compression side needle 24ay can be guided by the guide portion 24a1y in the piston rod 11y and can move in the axial direction without axial vibration.

[0042] The compression side damping force regulating valve 24y can cut off the compression side damping force regulating passage 23y when the compression side needle 24ay is seated on the compression side annular valve seat 11b3y, and when the compression side needle 24ay is withdrawn from the compression side annular valve seat 11b3y, the compression side damping force regulating passage 23y is opened, and by adjusting the size of the gap (flow path area) between the compression side needle 24ay and the compression side annular valve seat 11b3y, the resistance applied to the flow of the liquid flowing through the compression side damping force regulating passage 23y can be adjusted. In addition, a notch 24a3y is provided on the outer periphery of the guide portion 24a1y, and since the guide portion 24a1y does not close the compression side damping force regulating passage 23y, when the compression side damping force regulating valve 24y is opened, the communication between the second compression side chamber R2y and the second liquid storage chamber Ry is ensured through the compression side damping force regulating passage 23y.

[0043] The flow path area of ​​the compression side damping force regulating valve 24y can be adjusted by operating the compression side adjuster 25y housed in the inner circumference of the second cover 5y. The compression side adjuster 25y has a threaded portion on the outer circumference, and is rotatably inserted into the inner circumference of a cylindrical spring adjuster 26y in the circumferential direction. The spring adjuster is rotatably installed in the inner cylinder portion 5by of the second cover 5y in the circumferential direction. The feed thread mechanism is formed by the compression side adjuster 25y and the spring adjuster 26y. If the compression side adjuster 25y is rotated relative to the spring adjuster 26y, the compression side adjuster 25y is rotated in the second cover 5y. Figure 3 Between the compression side adjuster 25y and the compression side needle 24ay, the cylindrical compression side control rod 30y moves in the axial direction ( Figure 3The compression side adjuster 25y is inserted into the piston rod body 11ay movably (in the vertical direction in the compression side), and the vertical displacement of the compression side adjuster 25y is transmitted to the compression side needle 24ay through the compression side control rod 30y. In this way, if the compression side adjuster 25y provided on the second cover 5y at the upper end of the second front fork F2y is operated, the size of the flow path area of ​​the compression side damping force regulating valve 24y can be changed.

[0044] In addition, 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 installed on the threaded portion of the outer periphery of the spring adjuster 26y. The nut 28y has a spring seat 28ay that protrudes toward the outer periphery of the inner cylinder portion 5by through the long hole 5cy of the inner cylinder portion 5by of the second cover 5y. Moreover, a suspension spring 29y is sandwiched between the spring seat 28ay and the upper end of the shell portion 15by of the rod guide 15y, and the suspension spring 29y applies force in a manner to extend the second fork body Fy, thereby elastically supporting the body B of the suspension straddle type vehicle V. When the spring adjuster 26y is rotated, the nut 28y is restricted from rotating by the inner cylinder portion 5by, so that the nut 28y is rotated. Figure 3 The vertical movement causes the support position of the suspension spring 29y of the spring seat 28ay to be displaced in the vertical direction, so that the vehicle height of the suspension straddle type vehicle V can be adjusted.

[0045] The structure of the suspension device S is described above, and the operation of the suspension device S is described below. First, when the first front fork F1x and the second front fork F2y in the suspension device S are extended, the first shock absorber Dx and the second shock absorber Dy are also extended. When the first shock absorber Dx and the second shock absorber Dy are extended, the pistons 12x and 12y move upward in the figure in the cylinders 10x and 10y, shrinking the extension side chambers R1x and R1y and expanding the compression side chambers R2x and R2y. Therefore, the liquid pushes open the extension side damping valves 16x and 16y of the pistons 12x and 12y, flows through the extension side damping passages 12ax and 12ay, and moves from the extension side chambers R1x and R1y to the compression side chambers R2x and R2y. Since the expansion-side damping valves 16x, 16y provide resistance to the flow of the liquid flowing through the expansion-side damping passages 12ax, 12ay, the pressure in the expansion-side chambers R1x, R1y rises.

[0046] In the first shock absorber Dx, the extension-side damping force adjustment channel 20x and the extension-side damping force adjustment channel 12ax are connected to the first extension-side chamber R1x and the first compression-side chamber R2x in parallel. Moreover, the extension-side damping force adjustment valve 21x is provided on the extension-side damping force adjustment channel 20x. Therefore, when the extension-side damping force adjustment valve 21x is opened, the liquid in the first extension-side chamber R1x flows not only through the extension-side damping channel 12ax but also through the extension-side damping force adjustment channel 20x to move to the first compression-side chamber R2x. Therefore, by operating the extension side adjuster 22x, the flow path area between the extension side needle 21ax and the extension side annular valve seat 11b4x in the extension side damping force regulating valve 21x can be adjusted, and then the resistance applied to the flow of liquid flowing through the extension side damping force regulating channel 20x can be adjusted. Therefore, the pressure in the first extension side chamber R1x when the first shock absorber Dx is extended can be adjusted.

[0047] On the other hand, as the piston rods 11x and 11y withdraw from the cylinders 10x and 10y, a shortage of liquid is generated in the expanded compression side chambers R2x and R2y, and the amount thereof is equal to the volume of the piston rods 11x and 11y withdrawn from the cylinders 10x and 10y. The shortage of liquid flows from the liquid storage chambers Rx and Ry through the suction passages 13a2x and 13a2y and is supplied to the compression side chambers R2x and R2y due to the opening of the extension side check valves 33x and 33y. Therefore, the pressure in the compression side chambers R2x and R2y is substantially equal to the pressure in the liquid storage chambers Rx and Ry.

[0048] In this way, when the suspension device S is extended, the pressure in the extension side chambers R1x and R1y rises to a level higher than the pressure in the compression side chambers R2x and R2y, and acts on the pistons 12x and 12y, so that the first shock absorber Dx generates an extension side damping force that hinders the extension of the first front fork F1x, and the second shock absorber Dy generates an extension side damping force that hinders the extension of the second front fork F2y.

[0049] Furthermore, in the first shock absorber Dx, the extension-side damping force regulating valve 21x can adjust the extension-side damping force by adjusting the resistance applied to the flow of the liquid flowing from the first extension-side chamber R1x to the first compression-side chamber R2x through the extension-side damping force regulating passage 20x. When the entire suspension device S is extended, the damping force that hinders the extension is the sum of the damping forces generated by the first shock absorber Dx and the second shock absorber Dy. Therefore, by adjusting the extension-side damping force of the first shock absorber Dx in the first front fork F1x, the extension-side damping force when the suspension device S is extended can be adjusted.

[0050] Next, when the first front fork F1x and the second front fork F2y in the suspension device S are contracted, the first shock absorber Dx and the second shock absorber Dy are also contracted. When the first shock absorber Dx and the second shock absorber Dy are contracted, the pistons 12x and 12y move downward in the figure in the cylinders 10x and 10y, shrinking the compression side chambers R2x and R2y and expanding the extension side chambers R1x and R1y. Therefore, the liquid pushes open the compression side check valves 17x and 17y of the pistons 12x and 12y, flows through the compression side passages 12bx and 12by, and moves from the compression side chambers R2x and R2y to the extension side chambers R1x and R1y. In addition, since the piston rods 11x and 11y enter the cylinders 10x and 10y, an excess of liquid is generated in the cylinders 10x and 10y, and the amount thereof is equal to the volume amount of the piston rods 11x and 11y entering the cylinders 10x and 10y. The excess liquid pushes the compression side damping valves 32x and 32y open, flows through the compression side damping passages 13a1x and 13a1y, and moves from the compression side chambers R2x and R2y to the liquid storage chambers Rx and Ry. The compression side check valves 17x and 17y hardly apply resistance to the flow of liquid, so that the pressure in the extension side chambers R1x and R1y is substantially equal to the pressure in the compression side chambers R2x and R2y. On the other hand, since the compression side damping valves 32x and 32y apply resistance to the flow of liquid flowing through the compression side damping passages 13a1x and 13a1y, the pressure in the cylinders 10x and 10y rises.

[0051] In the second shock absorber Dy, the compression side damping force adjustment channel 23y and the compression side damping channel 13a1y are connected in parallel to the second compression side chamber R2y and the second liquid storage chamber Ry. In addition, a compression side damping force adjustment valve 24y is provided on the compression side damping force adjustment channel 23y. Therefore, when the compression side damping force adjustment valve 24y is opened, the liquid in the second compression side chamber R2y flows not only through the compression side damping channel 13a1y but also through the compression side damping force adjustment channel 23y to move to the second liquid storage chamber Ry. Therefore, by operating the compression side adjuster 25y, 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 is adjusted, and the resistance applied to the flow of the liquid flowing through the compression side damping force adjustment channel 23y can be adjusted, so that the magnitude of the pressure in the cylinder 10y when the second shock absorber Dy is contracted can be adjusted.

[0052] In this way, when the suspension device S contracts, the pressure in the extension side chamber R1x, R1y and the pressure in the compression side chamber R2x, R2y rise by basically the same amount, the pressure in the extension side chamber R1x, R1y acts on the upper surface of the pistons 12x, 12y, and the pressure in the compression side chamber R2x, R2y acts on the lower surface of the pistons 12x, 12y, but because the pistons 12x, 12y are connected to the piston rods 11x, 11y, the pressure area of ​​the lower surface of the pistons 12x, 12y is larger than the pressure area of ​​the upper surface, thereby the first shock absorber Dx generates a compression side damping force that hinders the contraction of the first front fork F1x, and the second shock absorber Dy generates a compression side damping force that hinders the contraction of the second front fork F2y.

[0053] Furthermore, in the second shock absorber Dy, the compression side damping force regulating valve 24y can adjust the compression side damping force by adjusting the resistance applied to the flow of the liquid flowing from the second compression side chamber R2y to the second liquid storage chamber Ry through the compression side damping force regulating passage 23y. Since the damping force that hinders the contraction when the entire suspension device S contracts is the sum of the damping forces generated by the first shock absorber Dx and the second shock absorber Dy, the compression side damping force when the suspension device S contracts can be adjusted by adjusting the compression side damping force of the second shock absorber Dy in the second front fork F2y.

[0054] Therefore, in the suspension device S of this embodiment, the extension side damping force can be adjusted by operating the extension side adjuster 22x installed on the first cover 5x installed on 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 installed on the second cover 5y installed on the upper end of the second front fork F2y.

[0055] As described above, the suspension device S of the present embodiment includes a first front fork F1x and a second front fork F2y for suspending the front wheel W of the straddle-type vehicle V on the vehicle body B, wherein the first front fork F1x includes: a telescopic first fork body Fx including a first vehicle body side tube 3x, a first axle side tube 4x that is movable in the axial direction relative to the first vehicle body side tube 3x, a first cover 5x for closing the upper end of the first vehicle body side tube 3x, a first axle bracket 6x for closing the lower end of the first axle side tube 3x and for holding the axle Ws of the front wheel W; a first shock absorber Dx including a first axle bracket 6x connected to the first axle bracket 6x; A cylinder 10x, a first piston rod 11x which can be movably inserted into the first cylinder 10x along the axial direction and the upper end of which is connected to the first cover 5x, and a first piston 12x which is connected to the first piston rod 11x and inserted into the first cylinder 10x and divides the interior of the first cylinder 10x into a first extension side chamber R1x and a first compression side chamber R2x filled with liquid. The first shock absorber expands and contracts along with the expansion and contraction of the first fork body Fx to generate a damping force for hindering the expansion and contraction of the first fork body Fx; a first liquid storage chamber Rx for storing liquid is formed in the space between the first fork body Fx and the first shock absorber Dx. The second front fork F2y includes: a telescopic second fork body Fy, which includes a second body side tube 3y, a second axle side tube 4y that can move in the axial direction relative to the second body side tube 3y, a second cover 5y for closing the upper end of the second body side tube 3y, and a second axle bracket 6y for closing the lower end of the second axle side tube 4y and for holding the axle Ws of the front wheel W; a second shock absorber Dy, which includes a second cylinder 10y connected to the second axle bracket 6y, and a second cylinder 10y that can be inserted into the second cylinder 10y movably in the axial direction. A second piston rod 11y is provided inside the second fork body 5y and the upper end of the second piston is connected to the second cover 5y, and a second piston 12y is connected to the second piston rod 11y and inserted into the second cylinder 10y to divide the interior of the second cylinder 10y into a second extension side chamber R1y and a second compression side chamber R2y. The second shock absorber expands and contracts along with the expansion and contraction of the second fork body Fy, thereby generating a damping force for hindering the expansion and contraction of the second fork body Fy. A second liquid storage chamber Ry for storing liquid is formed in the space between the second fork body Fy and the second shock absorber Dy. The first shock absorber Dx has an extension side damping force adjustment channel 20x for connecting the first extension side chamber R1x and the first compression side chamber R2x, an extension side damping force adjustment valve 21x arranged in the middle of the extension side damping force adjustment channel 20x, and an extension side adjuster (extension side adjustment part) 22x arranged on the first cover 5x and capable of adjusting the resistance applied by the extension side damping force adjustment valve 21x to the flow of liquid flowing through the extension side damping force adjustment channel 20x.The second shock absorber Dy has a compression side damping force adjusting channel 23y that passes through the inside of the second piston rod 11y and is used to connect the second compression side chamber R2y and the second liquid storage chamber Ry, a compression side damping force adjusting valve 24y arranged in the middle of the compression side damping force adjusting channel 23y, and a compression side adjuster (compression side adjusting part) 25y that is arranged on the second cover 5y and can adjust the resistance applied by the compression side damping force adjusting valve 24y to the flow of liquid flowing through the compression side damping force adjusting channel 23y.

[0056] In the suspension device S constructed in this way, the first shock absorber Dx in the first front fork F1x can generate damping force when extending and contracting, and the extension-side damping force of the first shock absorber Dx can be adjusted by the extension-side adjuster (extension-side adjusting part) for operating the extension-side damping force adjusting valve 21x, and the second shock absorber Dy in the second front fork F2y can generate damping force when extending and contracting, and the compression-side damping force of the second shock absorber Dy can be adjusted by the compression-side adjuster (compression-side adjusting part) 25y for operating the compression-side damping force adjusting valve 24y. Moreover, in the suspension device S constructed in this way, the extension-side adjuster (extension-side adjusting part) 22x for operating the extension-side damping force adjusting valve 21x is mounted on the first cover 5x at the upper end of the first front fork F1x, and the compression-side adjuster (compression-side adjusting part) 25y for operating the compression-side damping force adjusting valve 24y is mounted on the second cover 5y at the upper end of the second front fork F2y. Therefore, according to the suspension device S of the present embodiment, the extension-side damping force and the compression-side damping force can be adjusted at the upper end sides of the first front fork F1x and the second front fork F2y.

[0057] In the suspension device S of the present embodiment, the extension-side adjustment part is an extension-side adjuster 22x that can be manually operated by the user, and the compression-side adjustment part is a compression-side adjuster 25y that can be manually operated by the user. The user of the suspension device S can adjust the extension-side damping force by operating the extension-side adjuster 22x at the upper end of the first front fork F1x, and can adjust the compression-side damping force by operating the compression-side adjuster 25y at the upper end of the second front fork F2y while riding on the suspension straddle-type vehicle V. In addition, in the suspension device S of the present embodiment, since it is not necessary to get off the vehicle and bend over to adjust the extension-side damping force and the compression-side damping force, the extension-side damping force and the compression-side damping force can be adjusted more easily.

[0058] In addition, in the suspension device S of the present embodiment, since both the first shock absorber Dx and the second shock absorber Dy generate damping force when they are extended and retracted, the first shock absorber Dx generates damping force only when it is extended, and the maximum pressure in the cylinders 10x and 10y can be reduced compared to the case where the second shock absorber Dy generates damping force only when it is retracted. Therefore, according to the suspension device S of the present embodiment, the weight of the components constituting the first shock absorber Dx and the second shock absorber Dy can be reduced, and the cost can be reduced.

[0059] In addition, in the above case, the suspension device S has an extension-side adjuster 22x as an extension-side adjustment part to adjust the flow path area of ​​the extension-side damping force adjustment valve 21x, and has a compression-side adjuster 25y as a compression-side adjustment part to adjust the flow path area of ​​the compression-side damping force adjustment valve 24y, but the extension-side adjustment part and the compression-side adjustment part may be a linear actuator having a solenoid, or a linear actuator composed of a rotary motor and a feed screw mechanism that converts the rotation of the motor rotor into a linear motion, etc. In the suspension device S having such a structure, the linear actuator does not need to be arranged at the position closest 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, and the protection of the linear actuator and the handling of the wiring of the linear actuator are also made very easy.

[0060] Furthermore, in the suspension device S of the present embodiment, as described above, the extension damping force regulating valve 21x is a needle valve, but it may be a valve with a gate that opens or closes the port 11b3x provided on the piston rod 11x by displacement in the axial direction or displacement in the circumferential direction. Further, in the suspension device S of the present embodiment, as described above, the compression damping force regulating valve 24y is a needle valve, but it may be a valve with a gate that opens or closes the horizontal hole 11a1y provided on the piston rod 11y by displacement in the axial direction or displacement in the circumferential direction. The extension damping force regulating valve 21x and the compression damping force regulating valve 24y are composed of a valve body that can be seated on the annular valve seat 11b4x, 11b3y and a spring that urges the valve body to seat on the annular valve seat 11b4x, 11b3y. In this case, the spring force can be adjusted by the extension side adjuster 22x, the valve opening pressure of the extension side damping force adjusting valve 21x can be changed, and the resistance applied to the flow of the liquid flowing through the extension side damping force adjusting passage 20x can be adjusted. The spring force can be adjusted by the compression side adjuster 25y, the valve opening pressure of the compression side damping force adjusting valve 24y can be changed, and the resistance applied to the flow of the liquid flowing through the compression side damping force adjusting passage 23y can be adjusted. In this way, even if the extension side damping force adjusting valve 21x and the compression side damping force adjusting valve 24y are changed to valves other than needle valves, the extension side adjusting unit and the compression side adjusting unit can be used as linear actuators instead of the adjusters 22x and 25y.

[0061] In the suspension device S of the present embodiment, the compression side damping force adjustment passage 23y is formed by a horizontal hole 11a1y opened from the side of the second piston rod 11y and always facing the second liquid storage chamber Ry, and a vertical hole provided in the second piston rod 11y so as to communicate the second compression side chamber R2y with the horizontal hole 11a1y, and the horizontal hole 11a1y is arranged below the liquid level Oy of the liquid in the second liquid storage chamber Ry. According to the suspension device S configured in this manner, even when the second front fork F2y is not extended or retracted for a long time, the horizontal hole 11a1y is always arranged below the liquid level Oy regardless of the extension or retraction state of the second shock absorber Dy, so that the liquid level in the compression side damping force adjustment passage 23y does not drop to a position below the compression side damping force adjustment valve 24y. Assuming that the liquid level in the compression side damping force adjustment passage 23y drops to a position below the compression side damping force adjustment valve 24y, the second front fork F2y performs several extension and contraction operations, and the compression side damping force cannot be adjusted until the liquid level in the compression side damping force adjustment passage 23y rises to the compression side damping force adjustment valve 24y. In contrast, according to the configuration of the above-mentioned suspension system S, the compression side damping force adjustment valve 24y is always arranged in the liquid, and the liquid level in the compression side damping force adjustment passage 23y does not drop to a position below the compression side damping force adjustment valve 24y, and the compression side damping force adjustment function of the compression side damping force adjustment valve 24y is not impaired when the second shock absorber Dy contracts. In addition, even if the horizontal hole 11a1y is not usually arranged below the liquid level Oy, the effect of the present invention that the extension side damping force and the compression side damping force can be easily adjusted does not disappear.

[0062] Furthermore, in the suspension device 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 regulating valve 21x has an extension-side needle 21ax inserted into the first piston rod 11x movably along the axial direction and an extension-side annular valve seat 11b4x provided on the inner periphery of the first piston rod 11x. The compression-side damping force regulating valve 24y has a compression-side needle 24ay inserted into the second piston rod 11y movably along the axial direction and a compression-side annular valve seat 11b3y provided on the inner periphery of the second piston rod 11y. The first shock absorber Dx has an extension-side control rod 27x, which is inserted into the first piston rod 11x and transmits the axial movement of the extension-side adjuster (extension-side adjusting portion) 22x to the extension-side needle. The second shock absorber Dy has a compression side control rod 30y, which is inserted into the second piston rod 11y, and the axial movement of the compression side adjuster (compression side adjustment part) 25y is transmitted to the compression side needle 24ay. The first shock absorber Dx and the second shock absorber Dy have the same components except for the first piston rod 11x, the second piston rod 11y, the extension side needle 22ax, the compression side needle 24ay, the extension side control rod 27x and the compression side control rod 30y. The suspension device S constructed in this way is composed of the same components as the first shock absorber Dx and the second shock absorber Dy. Therefore, when manufacturing the first shock absorber Dx and the second shock absorber Dy, the number of components can be kept to a minimum, and the manufacturing cost of the suspension device S can be reduced. Furthermore, in the suspension device S of the present embodiment, since the first fork main body Fx and the second fork main body Fy are also formed of the same member, the manufacturing cost of the suspension device S can be further reduced.

[0063] In addition, in the second front fork F2y in the suspension device S of the above-mentioned embodiment, the horizontal hole 11a1y is arranged so as to be always arranged below the liquid level Oy of the liquid in the second liquid storage chamber Ry with respect to the second piston rod 11y, so that when the second shock absorber Dy switches from extension to contraction, the generation of the damping force will not be delayed, and the second shock absorber Dy can also be configured as follows: Figure 4 The second shock absorber D1y in a modified example shown is generally provided with a check valve 34y in the compression side damping force regulating channel 23y, which only allows liquid to flow from the second compression side chamber R2y to the second storage chamber Ry, and the check valve and the compression side damping force regulating valve 24y are always arranged in series at a position lower than the liquid level Oy of the liquid in the second storage chamber Ry.

[0064] The check valve 34y has: a cylindrical valve seat 34ay with a flange; a spherical valve body 34by that can be seated on the valve seat 34ay; a housing 34cy that is a bottomed cylindrical shape installed on the outer periphery of the cylindrical portion of the valve seat 34ay and has holes on the side and bottom; and a spring 34dy that is sandwiched between the housing 34cy and the valve body 34by to apply force so that the valve body 34by is seated on the valve seat 34ay. In this way, the check valve 34y is modularized and accommodated in the large diameter portion 11b1y of the center rod 11by for holding the piston 12y. In addition, the flange of the valve seat 34ay of the check valve 34y is clamped by the front end of the piston rod body 11ay and the step portion between the large diameter portion 11b1y and the small diameter portion 11b2y of the center rod 11by, and is fixed in the piston rod 11y. In this way, if the check valve 34y is modularized, it is easier to set it in the piston rod 11y. In addition, in the second shock absorber D1y, since the check valve 34y is housed in the center rod 11by, Figure 4 As shown, a compression-side damping force regulating valve 24y is provided in the inner cylinder portion 5by of the second cover 5y, and a passage 40y for communicating the second reservoir chamber Ry with the interior of the piston rod 11y is provided on the second cover 5y.

[0065] In the second shock absorber Dy1 constructed in this manner, 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 falling, and the compression-side damping force adjustment valve 24y is always in the liquid state. In addition, according to the suspension device S in which the second shock absorber Dy1 of the first modified example is accommodated in the second front fork F2y, when the second shock absorber Dy1 is contracted, the compression-side damping force adjustment function of the compression-side damping force adjustment valve 24y is not impaired.

[0066] In addition, regarding the configuration of the compression side damping force regulating valve 24y and the check valve 34y relative to the compression side damping force regulating passage 23y, in order to prevent the generation of the damping force in the second shock absorber Dy1 from being delayed, the compression side damping force regulating valve 24y and the check valve 34y are configured in series, and the check valve 34y is always configured at a position lower than the liquid level Oy of the liquid in the second liquid storage chamber Ry. Therefore, as long as these conditions are met, the configuration of the compression side damping force regulating valve 24y and the check valve 34y can be arbitrarily determined. Therefore, as Figure 4 As shown, the compression side damping force regulating valve 24y is provided in the inner cylinder portion 5by of the second cover 5y, and a structure can also be adopted to make the second liquid storage chamber Ry and the piston rod 11y communicate with the second cover 5y, such as Figure 3As shown, the compression side damping force regulating valve 24y may be provided in the piston rod 11y. In addition, by accommodating the check valve 34y in the large diameter portion 11b1y where space can be secured in the center rod 11by, the check valve 34y can be easily provided on the piston rod 11y, and even if the second shock absorber D1y moves the full stroke, it will not leave the cylinder 10y, so the check valve 34y can be reliably arranged below the liquid surface Oy. In addition, if the check valve 34y is modularized as described above, it is easier to provide it on the second shock absorber D1y, and as long as it functions as a check valve, the structure can be freely changed in design.

[0067] Although the preferred embodiments of the present invention have been described in detail above, modifications, variations and changes may be made without departing from the scope of the claims. Explanation of symbols

[0068] 3x First Body Side Tubes 3y Second body side pipe 4x 1st axle side tube 4y Second axle side tube 5x First Cover 5y Second Cover 6x First axle bracket 6y Second axle bracket 10x First Cylinder 10y Second cylinder 11x First piston rod 11b4x Extension side annular seat 11y Second piston rod 11a1y Horizontal hole 11b3y Compression side annular seat 12x First Piston 12y Second piston 20x extension side damping force adjustment channels 21x Extension side damping force adjustment valve 21ax Extended side needle 22x Extension side adjuster (Extension side adjustment part) 23y Compression side damping force adjustment channel 24y Compression side damping force adjustment valve 24ay compression side needle 25y Compression side adjuster (compression side adjustment part) 27x Extended side levers 30y Compression side lever 34y Check valve B Body Dx first shock absorber Dy, D1y Second shock absorber F1x first fork F2y Second Fork Fx First Fork Body Fy Second fork body O Liquid level S suspension Rx First Reservoir Ry Second liquid storage chamber R1x First elongated side chamber R1y Second elongated side chamber R2x First compression side chamber R2y Second compression side chamber V-suspension straddle-type vehicle W Front wheel Ws Axle

Claims

1. A suspension device comprising a first front fork and a second front fork for suspending a front wheel of a suspension straddle-type vehicle on a vehicle body, wherein: The first front fork has: a telescopic first fork body having a first vehicle body side tube, a first axle side tube movable in the axial direction relative to the first vehicle body side tube, a first cover for closing the upper end of the first vehicle body side tube, and a first axle bracket for closing the lower end of the first axle side tube and holding the axle of the front wheel, The first shock absorber includes a first cylinder connected to the first axle bracket, a first piston rod inserted into the first cylinder in an axially movable manner and connected to the first cover at an upper end, and a first piston connected to the first piston rod and inserted into the first cylinder to divide the interior of the first cylinder into a first extension side chamber and a first compression side chamber. The first shock absorber expands and contracts with the expansion and contraction of the first fork body to generate a damping force that hinders the expansion and contraction of the first fork body. forming a first liquid storage chamber for storing liquid in a space between the first fork body and the first shock absorber; The second front fork has: a telescopic second fork body having a second body side tube, a second axle side tube movable in the axial direction relative to the second body side tube, a second cover for closing the upper end of the second body side tube, and a second axle bracket for closing the lower end of the second axle side tube and holding the axle of the front wheel, The second shock absorber includes a second cylinder connected to the second axle bracket, a second piston rod inserted into the second cylinder in an axially movable manner and having an upper end connected to the second cover, and a second piston connected to the second piston rod and inserted into the second cylinder to divide the interior of the second cylinder into a second extension side chamber and a second compression side chamber. The second shock absorber expands and contracts as the second fork body expands and contracts to generate a damping force that hinders the expansion and contraction of the second fork body. forming a second liquid storage chamber for storing liquid in a space between the second fork body and the second shock absorber; The first shock absorber comprises an extension-side damping force adjustment passage for connecting the first extension-side chamber and the first compression-side chamber, an extension-side damping force adjustment valve provided in the middle of the extension-side damping force adjustment passage, and an extension-side adjustment portion provided on the first cover and capable of adjusting the resistance applied by the extension-side damping force adjustment valve to the flow of liquid flowing through the extension-side damping force adjustment passage, The second shock absorber includes a compression side damping force adjustment channel that connects the second compression side chamber and the second liquid storage chamber through the inside of the second piston rod, a compression side damping force adjustment valve arranged in the middle of the compression side damping force adjustment channel, and a compression side adjustment part that is arranged on the second cover and can adjust the resistance applied by the compression side damping force adjustment valve to the flow of liquid flowing through the compression side damping force adjustment channel.

2. The suspension device according to claim 1, wherein: The compression side damping force adjustment channel is formed by a transverse hole and a vertical hole, wherein the transverse hole opens from the side of the second piston rod and is always opposite to the second liquid storage chamber, and the vertical hole is arranged on the second piston rod and is used to connect the second compression side chamber and the transverse hole; The horizontal hole is arranged below the liquid level of the liquid in the second liquid storage chamber.

3. The suspension device according to claim 1, wherein: The compression side damping force adjustment channel is formed by a transverse hole and a vertical hole, wherein the transverse hole opens from the side of the second piston rod and is always opposite to the second liquid storage chamber, and the vertical hole is arranged on the second piston rod and is used to connect the second compression side chamber and the transverse hole; The second shock absorber has a check valve, which is arranged in series with the compression side damping force regulating valve on the way of the compression side damping force regulating channel, and only allows liquid to flow from the second compression side chamber to the second liquid storage chamber; The check valve is disposed below a liquid level of the liquid in the second liquid storage chamber.

4. The suspension device according to claim 1, wherein: The first piston rod and the second piston rod are both cylindrical. The extension-side damping force regulating valve comprises an extension-side needle inserted into the first piston rod so as to be movable in the axial direction and an extension-side annular valve seat provided on the inner periphery of the first piston rod; The compression side damping force regulating valve comprises a compression side needle inserted into the second piston rod so as to be movable in the axial direction and a compression side annular valve seat provided on the inner periphery of the second piston rod; The first shock absorber has an extension side control rod, which is inserted into the first piston rod and transmits the power of the extension side adjustment part to the extension side needle; The second shock absorber has a compression side control rod, which is inserted into the second piston rod and transmits the power of the compression side adjustment part to the compression side needle; The first shock absorber and the second shock absorber have the same components except for the first piston rod, the second piston rod, the extension side needle, the compression side needle, the extension side control rod and the compression side control rod.

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