JP2024129779A - Damper and front fork - Google Patents

Abstract

To provide a front fork capable of restraining an attenuating force from being excessive even when it is stroked at high speed.SOLUTION: A front fork F comprises an expansion body 1 having a vehicle body side tube 2 and a wheel side tube 3, and a damper D housed in the expansion body 1. The damper D comprises: a cylinder 10; a shaft member 13 inserted in the cylinder 10; a leaf valve 14 fixed to the shaft member 13 and allowing axial flexion; and a valve seat member 15 mounted to the shaft member 13, blocking the cylinder 10 into two operation chambers (R2, L), and having a port 15e communicating the operation chambers (R2, L) with each other, and a seat part 15b opposed to an outer periphery of the leaf valve 14. The valve seat member 15 has an elastic seal ring 15c mounted to the outer periphery and tightly contacting an inner periphery of the cylinder 10.SELECTED DRAWING: Figure 2

Description

The present invention relates to a damper and a front fork.

Front forks are used in suspension devices that suspend the front wheel of a saddle-type vehicle such as a two-wheeled or three-wheeled vehicle from the vehicle body, and include, for example, a telescopic body having an outer tube and an inner tube that is axially slidably inserted into the outer tube, and a damper that is housed in the telescopic body and interposed between the outer tube and the inner tube to generate a damping force when telescopic. When such a front fork telescopically expands or contracts while traveling, the damper generates a damping force, suppressing vibrations of the vehicle body and improving the ride comfort of the vehicle.

In saddle-type vehicles, compared to four-wheeled vehicles, the front wheels are displaced significantly relative to the vehicle body when starting, braking, or driving on rough roads. This can cause the damper installed in the front fork to stroke at high speeds, which can increase the amount of hydraulic oil passing through the damping valve in the damper and result in excessive damping force.

Damping valves that can suppress excessive damping force while suppressing vibration of the vehicle body by increasing the damping coefficient when the stroke speed is low and decreasing the damping coefficient when the stroke speed is high are used in four-wheeled automobiles. For example, this damping valve is equipped with an annular leaf valve whose inner periphery is fixed to the piston rod and allows bending on the outer periphery, and an annular valve case fixed to the piston rod. The valve case is provided with a port that communicates with the main valve, and a cylindrical opposing seat that faces the outer periphery of the leaf valve without contacting it on its inner periphery, forming an annular gap between the port and the cylinder (see, for example, Patent Document 1).

When the stroke speed of the damper is in the low speed range, the leaf valve does not bend much and limits the flow area between the opposing seat to a minimum, so the damping force characteristic rises sharply in response to the stroke speed, whereas when the stroke speed becomes high, the leaf valve bends and increases the flow area, suppressing any further increase in damping force. Therefore, if such a damping valve used in a four-wheeled vehicle is used as a damping valve in a front fork damper, it is expected that the ride comfort of a saddle-type vehicle will be improved.

JP 2019-183918 A

As mentioned above, in front forks used in saddle-type vehicles, the damper strokes at high speed, so a large amount of hydraulic oil passes through the damping valve. This means that when the leaf valve bends and moves axially away from the opposing seat, it is necessary to increase the flow area.

However, conventional damping valves have a structure in which the cylindrical portion of the valve case, which is fixed to the piston rod, faces the cylinder with a sufficiently large gap so as not to interfere with the cylinder. Because the inner diameter of the opposing seat portion provided on the inner circumference of the cylindrical portion cannot be made large, it is difficult to ensure a large flow area when the leaf valve bends and moves axially away from the opposing seat portion.

Therefore, even if a conventional damping valve is applied directly to a front fork damper, excessive damping force is generated when the damper strokes at high speed, making it difficult to improve the ride comfort of saddle-type vehicles.

Therefore, the present invention aims to provide a damper and front fork that can prevent the damping force from becoming excessive even when stroking at high speeds.

In order to solve the above problems, the damper of the present invention comprises a cylinder, a shaft member inserted into the cylinder, a leaf valve that is annular and fixed on its inner periphery to the shaft member and allows axial deflection on its outer periphery, and a valve seat member that is annular and attached to the shaft member to divide the inside of the cylinder into two working chambers, and has a port that connects the working chambers, and an opposing seat on its inner periphery that faces the outer periphery of the leaf valve, and the valve seat member has an elastic seal ring attached to its outer periphery and in close contact with the inner periphery of the cylinder.

In order to solve the above problem, the front fork of the present invention includes a telescopic body having a vehicle body tube and a wheel side tube that is movable in the axial direction relative to the vehicle body tube, and a damper that is housed in the telescopic body and expands and contracts together with the telescopic body to generate a damping force. The damper includes a cylinder, a shaft member inserted into the cylinder, an annular leaf valve whose inner periphery is fixed to the shaft member and whose outer periphery is allowed to bend in the axial direction, and a valve seat member that is annular and attached to the shaft member to divide the inside of the cylinder into two working chambers, has a port that communicates between the working chambers, and has an opposing seat on its inner periphery that faces the outer periphery of the leaf valve. The valve seat member has an elastic seal ring that is attached to the outer periphery and in close contact with the inner periphery of the cylinder.

In a damper and front fork configured in this manner, the seal ring can seal between the valve seat member and the cylinder, allowing the inner diameter of the valve seat member and the outer diameter of the leaf valve to be large, ensuring a large flow area when the leaf valve flexes and shifts axially relative to the annular valve seat to open.

Furthermore, the outer diameter of the valve seat member in the front fork may be set to a diameter that allows the valve seat member to be displaced radially within the cylinder. In a front fork configured in this way, since there is radial play between the cylinder and the valve seat member, even if the valve seat member that is aligned with the shaft member is housed in the cylinder, the valve seat member does not receive a large load from the cylinder due to the fit other than the elastic force of the seal ring. Therefore, even if the inner diameter of the valve seat member and the outer diameter of the leaf valve are increased while sealing between the valve seat member and the cylinder with the seal ring, the leaf valve and the opposing seat portion do not become misaligned with the axis. In addition, since there is radial play between the cylinder and the valve seat member, the valve seat member does not bite into the inner circumference of the cylinder during the operation of inserting the shaft member into the cylinder, and good workability can be ensured.

In addition, in the front fork, the damper may include a piston rod that is axially inserted into the cylinder and connected to a vehicle body side tube, and a piston that is axially inserted into the cylinder and connected to the piston rod and divides the inside of the cylinder into an extension side chamber and a compression side chamber, the cylinder is connected to the wheel side tube, and the valve seat member divides the inside of the cylinder into two working chambers, the compression side chamber and a liquid chamber that is inside the extension body and communicates with a liquid reservoir chamber outside the cylinder.

With a front fork configured in this way, the leaf valve can be used as a valve for generating damping force when the front fork is retracted, and can also be used as a check valve when the front fork is extended, eliminating the need to install other valves, reducing manufacturing costs and making the front fork lighter.

In addition, in the front fork, the passage that connects the compression side chamber and the liquid reservoir chamber via the port of the valve seat member may be opened and closed only by the leaf valve. With a front fork configured in this way, there is no valve in series with the leaf valve for the passage, so even when the front fork contracts at a very high speed, such as when a saddle-type vehicle to which the front fork is applied runs over a large step while traveling on unpaved roads (off-road) called gravel or dirt, the leaf valve bends and opens significantly, ensuring a large flow area in the passage, and the damper does not generate excessive damping force, so the front fork contracts quickly, absorbing impact and improving the ride comfort of the vehicle.

Furthermore, in the front fork, the mounting portion of the seal ring on the valve seat member may be offset in the axial direction from the opposing seat portion of the valve seat member. With a front fork configured in this way, the valve seat member can be provided with a portion for forming the opposing seat portion that axially avoids the mounting portion that must be thickened to face the cylinder in order to mount the seal ring on the outer periphery. This makes it easier to ensure a flow area between the leaf valve and the opposing seat portion by increasing the inner diameter of the opposing seat portion compared to when the opposing seat portion is provided on the inner periphery of the mounting portion.

In addition, in the front fork, the mounting portion of the seal ring on the valve seat member may be shifted axially toward the compression side chamber with respect to the opposing seat portion of the valve seat member. In a front fork configured in this manner, when the valve seat member divides the compression side chamber and the liquid chamber within the cylinder, the leaf valve bends toward the liquid chamber side opposite the mounting portion, which must be thickened to mount the seal ring on the outer periphery, when the damper contracts, so the leaf valve does not interfere with the mounting portion. Therefore, with a front fork configured in this manner, the leaf valve is not interfered with by the mounting portion during contraction, making it easier to ensure a large flow area between the leaf valve and the opposing seat portion.

In the front fork, the valve seat member is cylindrical and faces the outer periphery of the cylinder, has an opposing seat on its inner periphery, and has a seal ring attached to its outer periphery, and is annular and has a partition wall that fits around the outer periphery of the shaft member, is connected to the inner periphery of the cylindrical part, and has a port, and the partition wall may be offset axially toward the compression side chamber from the opposing seat wall. In a front fork configured in this way, when the valve seat member divides the compression side chamber and the liquid chamber in the cylinder, when the damper contracts, the leaf valve bends toward the liquid chamber side opposite the partition wall that is disposed between the compression side chamber and the liquid chamber, so that the leaf valve does not interfere with the partition wall. Therefore, with a front fork configured in this way, the leaf valve is not interfered with by the partition wall during contraction, making it easier to ensure a large flow passage area between the leaf valve and the opposing seat wall.

The damper and front fork of the present invention can prevent the damping force from becoming excessive even during high-speed strokes.

1 is a vertical cross-sectional view of a damper and a front fork according to an embodiment of the present invention; 2 is a partially enlarged cross-sectional view of the damper and the front fork according to the embodiment of the present invention. FIG. 5 is a diagram showing damping force characteristics in a damper and a front fork according to an embodiment of the present invention. FIG.

The present invention will be described below based on the embodiment shown in the drawings. As shown in FIG. 1, the front fork F in one embodiment is configured with a telescopic body 1 having a vehicle body side tube 2 and a wheel side tube 3 and capable of expanding and contracting, and a damper D housed within the telescopic body 1 and interposed between the vehicle body side tube 2 and the wheel side tube 3. Although not shown, the damper D is interposed between the vehicle body and the front wheel of a saddle-type vehicle such as a two-wheeled vehicle or a three-wheeled vehicle to suppress vibration between the vehicle body and the front wheel.

As described above, the front fork F includes the telescopic body 1 and the damper D housed within the telescopic body. The telescopic body 1 includes the vehicle body side tube 2 and the wheel side tube 3 that is movable in the axial direction relative to the vehicle body side tube 2, and is therefore telescopic. The telescopic body 1 also includes a cap 4 that closes the upper end of the vehicle body side tube 2, and an axle bracket 5 that closes the lower end of the wheel side tube 3 and holds the axle of the front wheel, and the inside of the telescopic body 1 is sealed.

The wheel side tube 3 is inserted into the vehicle body side tube 2 from below, and can move axially relative to the vehicle body side tube 2. An annular bush 7 and an annular seal member 8 are provided on the inner circumference of the lower end of the vehicle body side tube 2, which slide against the outer circumference of the wheel side tube 3, and an annular bush 9 is attached to the outer circumference of the upper end of the wheel side tube 3. The bushes 7 and 9 allow the vehicle body side tube 2 and the wheel side tube 3 to move axially without axial wobble.

A cap 4 is screwed to the inner circumference of the upper end of the vehicle body side tube 2, and the upper end of the vehicle body side tube 2 is closed by the cap 4. The cap 4 is cylindrical and has a large diameter portion 4a that is screwed to the inner circumference of the opening at the upper end of the vehicle body side tube 2, and a small diameter portion 4b that extends downward from the lower end of the large diameter portion 4a in FIG. 1 and has an outer diameter smaller than that of the large diameter portion 4a. An adjuster 6 is screwed to the inner circumference of the large diameter portion 4a of the cap 4. When the adjuster 6 is rotated relative to the cap 4, it can move up and down in FIG. 1 relative to the cap 4.

The lower end of the wheel side tube 3 is closed by an axle bracket 5 that holds the axle of the front wheel (not shown), and the telescopic body 1 is connected to the front wheel by the axle bracket 5. The inside of the telescopic body 1 configured in this way is a space sealed from the outside by a seal member 8. The axle bracket 5 has a cylindrical portion 5a that is screwed to the outer periphery of the lower end of the wheel side tube 3, a hole 5b that is connected to the side of the cylindrical portion 5a and through which the axle (not shown) is inserted, and a step portion 5c and an annular protrusion 5d that are provided on the inner periphery of the cylindrical portion 5a with an axial gap. Although not shown, the axle bracket 5 may be provided with an attachment portion that allows the attachment of a brake caliper or the like. A screw groove is formed above the step portion 5c on the upper side of the cylindrical portion 5a in FIG. 1, and the outer periphery of the lower end of the wheel side tube 3 is screwed into the screw groove to fasten the axle bracket 5 and the wheel side tube 3.

In the front fork F of this embodiment, the telescopic body 1 is configured as an inverted type in which the wheel side tube 3 is inserted into the vehicle body side tube 2, but it may also be configured as an upright type in which the vehicle body side tube 2 is inserted into the wheel side tube 3.

The damper D is housed in the telescopic body 1. The damper D in this embodiment includes a cylinder 10 connected to the wheel side tube 3 via an axle bracket 5, a piston 11 inserted axially into the cylinder 10 and dividing the cylinder 10 into an extension side chamber R1 and a compression side chamber R2 filled with liquid, a piston rod 12 inserted axially into the cylinder 10 and connected at its upper end to the vehicle body side tube 2 via a cap 4 and at its lower end to the piston 11, a bottom cap 13 as an axial member inserted into the cylinder 10 from the lower end in FIG. 1 which is the wheel side tube end of the cylinder 10, and a leaf valve 14 and a valve seat member 15 attached to the bottom cap 13.

The space outside the damper D is filled with liquid and gas, and this space serves as a liquid reservoir R for storing the liquid.

The following describes each part of the damper D. The cylinder 10 is screwed to the bottom cap 13, which is an axial member fixed to the axle bracket 5 of the telescopic body 1, and is connected to the axle bracket 5 via the bottom cap 13. The cylinder 10 has a through hole 10a that opens to the side of the lower end and communicates the inside of the cylinder 10 with the liquid reservoir chamber R. In addition, an annular rod guide 20 is attached to the upper open end of the cylinder 10. The rod guide 20 is annular and has a guide portion 20a that slides against the outer periphery of the piston rod 12 that is screwed into the inner periphery of the upper end of the cylinder 10 and inserted into the inner periphery, and a cylindrical case portion 20b that protrudes upward from the upper end of the guide portion 20a. The liquid filled in the cylinder 10 and the liquid reservoir chamber R is, for example, hydraulic oil, but may be a liquid other than hydraulic oil.

A suspension spring 21 is interposed between the upper end of the case portion 20b of the rod guide 20 in FIG. 1 and the cap 4. The suspension spring 21 biases the vehicle body side tube 2 and the wheel side tube 3 in the axial direction away from each other, that is, in the direction of extending the telescopic body 1, and elastically supports the vehicle body, which is interposed between the vehicle body and the front wheel of the saddle-type vehicle with the front fork F.

The piston rod 12 comprises a cylindrical piston rod body 22 and a cylindrical piston retaining rod 23 that is connected to the lower end of the piston rod body 22 and holds the piston 11. The upper end of the piston rod 12 is connected to the inner circumference of the small diameter portion 4b of the cap 4 by screw connection, and the lower end side is inserted into the cylinder 10 through the inner circumference of the rod guide 20. The piston rod 12 can move relatively in the up and down direction in FIG. 1, which is the axial direction, together with the piston 11, with radial movement of the piston rod 12 restricted by the rod guide 20 and the piston 11 with respect to the cylinder 10.

As shown in FIG. 1, the piston retaining rod 23 in the piston rod 12 is cylindrical and has a large diameter cylindrical section 23a with a large outer diameter that is screwed to the outer periphery of the lower end of the piston rod main body 22, and a small diameter cylindrical section 23b with a small outer diameter to which the piston 11 is attached. The piston retaining rod 23 also has a hole 23c that communicates the inside and outside of the large diameter cylindrical section 23a, and forms a damping force adjustment passage DP that communicates the inside with the expansion side chamber R1 and the compression side chamber R2 through the hole 23c. Furthermore, a needle 24 that is movable in the vertical direction and changes the flow area of the damping force adjustment passage DP as it moves in the vertical direction is housed in the piston retaining rod 23.

A control rod 25 is inserted into the piston rod body 22 so as to be movable in the axial direction between the adjuster 6 screwed into the cap 4 and the needle 24. Therefore, when the adjuster 6 is rotated and displaced in the vertical direction in FIG. 1, the displacement of the adjuster 6 is transmitted to the needle 24 via the control rod 25, and the needle 24 is moved in the vertical direction in FIG. 1 within the piston holding rod 23, thereby adjusting the flow area of the damping force adjustment passage DP.

The outer periphery of the piston rod body 22 is provided with an annular lock piece 26 that enters the case portion 20b of the rod guide 20 when the damper D is fully contracted. The case portion 20b and the lock piece 26 form a hydraulic cushion device, and when the lock piece 26 enters the case portion 20b, the hydraulic cushion device increases the pressure inside the case portion 20b to suppress further contraction of the damper D.

The piston 11 is annular and fits around the outer periphery of the small diameter cylindrical portion 23b provided at the tip of the piston holding rod 23 of the piston rod 12, which is located at the lower end in FIG. 1, and is fixed to the small diameter cylindrical portion 23b by being clamped between the lower end of the large diameter cylindrical portion 23a and a piston nut 27 that is screwed to the lower end of the small diameter cylindrical portion 23b in FIG. 1. The piston 11 also contacts the inner periphery of the cylinder 10, and divides the inside of the cylinder 10 into an extension side chamber R1 and a compression side chamber R2, each of which is filled with liquid. Furthermore, the piston 11 has an extension side damping passage 11a and a compression side passage 11b that communicate in parallel between the extension side chamber R1 and the compression side chamber R2.

1, which is the compression side chamber end of the piston 11, is overlapped with an extension side damping valve 16 that opens and closes the outlet end of the extension side damping passage 11a and allows only the flow of liquid passing through the extension side damping passage 11a from the extension side chamber R1 to the compression side chamber R2 while providing resistance to the flow. The extension side damping valve 16 is a laminated leaf valve formed by laminating multiple annular plates, and its inner periphery is sandwiched between the small diameter cylindrical portion 23b and the piston nut 27 together with the piston 11 and fixed to the small diameter cylindrical portion 23b, allowing deflection on the outer periphery side. Therefore, when the extension side damping valve 16 deflects under the pressure of the extension side chamber R1 acting through the extension side damping passage 11a, it opens the extension side damping passage 11a and provides resistance to the flow of liquid passing through, while when its outer periphery is in contact with the piston 11, it closes the extension side damping passage 11a. Therefore, the extension side damping valve 16 sets the extension side damping passage 11a as a one-way passage that only allows the flow of liquid from the extension side chamber R1 to the compression side chamber R2.

1, which is the end of the extension side chamber of the piston 11, is provided with a compression side check valve 17 that opens and closes the outlet end of the compression side passage 11b and allows only the flow of liquid through the compression side passage 11b from the compression side chamber R2 to the extension side chamber R1. The compression side check valve 17 is configured with an annular plate that is axially movable on the outer periphery of the small diameter cylindrical portion 23b of the piston holding rod 23, and a spring that biases the annular plate toward the piston 11, and can move toward and away from the piston 11. The compression side check valve 17 opens the compression side passage 11b when it separates from the piston 11, and closes the compression side passage 11b when it is seated on the piston 11. Therefore, the compression side check valve 17 sets the compression side passage 11b as a one-way passage that allows only the flow of liquid from the compression side chamber R2 to the extension side chamber R1. In the above description, the compression side valve is the compression side check valve 17, but it may also be a damping valve that provides resistance to the flow of liquid passing through.

The bottom cap 13 that fixes the cylinder 10 to the axle bracket 5 functions as an axial member and is cylindrical. It has a small diameter portion 13a that holds the leaf valve 14 and the valve seat member 15 from the top end side in FIG. 2, which is the tip side, a medium diameter portion 13b that is connected to the bottom end of the small diameter portion 13a in FIG. 2 and has a larger outer diameter than the small diameter portion 13a, a large diameter portion 13c that is connected to the bottom end of the medium diameter portion 13b in FIG. 2 and has a larger outer diameter than the medium diameter portion 13b, and a flange portion 13d provided on the outer periphery of the bottom end of the large diameter portion 13c in FIG. 2.

The bottom cap 13 is inserted into the axle bracket 5 from the lower open end side of the tubular portion 5a of the axle bracket 5. When the bottom cap 13 is fully inserted into the axle bracket 5, the large diameter portion 13c fits into the inner circumference of the annular protrusion 5d provided on the inner circumference of the lower end of the tubular portion 5a of the axle bracket 5, and the flange portion 13d abuts against the annular protrusion 5d in the axial direction.

A threaded portion 13a1 is formed on the outer periphery of the tip side of the small diameter portion 13a, and a threaded portion 13c1 is also formed on the outer periphery of the upper end of the large diameter portion 13c in FIG. 2. The upper end side of the large diameter portion 13c is inserted into the inner periphery of the lower end of the cylinder 10, and the inner periphery of the lower end of the cylinder 10 is screwed to the threaded portion 13c1 of the large diameter portion 13c. When the cylinder 10 is screwed to the threaded portion 13c1 of the large diameter portion 13c, the small diameter portion 13a, the medium diameter portion 13b, and the upper end of the large diameter portion 13c of the bottom cap 13 are accommodated in the cylinder 10, and the lower end of the cylinder 10 and the flange portion 13d of the bottom cap 13 clamp the annular protrusion 5d of the axle bracket 5, so that the cylinder 10 and the bottom cap 13 are fixed to the axle bracket 5 and connected to the wheel side tube 3.

The medium diameter portion 13b is provided with a through hole 13b1 that communicates between the inside and outside of the medium diameter portion 13b and is also connected to a through hole 10a provided in the cylinder 10. The pressure side chamber R2 is connected to the liquid reservoir chamber R outside the cylinder 10 through the inside of the bottom cap 13, the through hole 13b1, and the through hole 10a of the cylinder 10. A needle 18 with a conical valve body at its tip is screwed to the inner circumference of the bottom cap 13. The needle 18 can be moved axially within the bottom cap 13 by rotating it, and the size of the flow passage area between the needle 18 and the annular valve seat 13e provided on the inner circumference of the bottom cap 13 can be adjusted by moving it closer to or farther from the annular valve seat 13e.

The annular valve stopper 30, annular spacer 31, annular leaf valve 14, annular spacer 32, and annular valve seat member 15 are assembled in order on the outer circumference of the small diameter portion 13a of the bottom cap 13, which is inserted into the cylinder 10. The valve stopper 30, spacer 31, leaf valve 14, spacer 32, and valve seat member 15 are fixed to the bottom cap 13 by being sandwiched between a nut 33 screwed into the threaded portion 13a1 of the small diameter portion 13a and a step portion formed at the boundary between the small diameter portion 13a and the medium diameter portion 13b of the bottom cap 13. In this way, the bottom cap 13 is inserted into the cylinder 10 and functions as an axial member that holds the leaf valve 14 and the valve seat member 15.

As shown in FIG. 2, the leaf valve 14 is annular, and the inner periphery is sandwiched between spacers 31 and 32 and is fixedly attached to the outer periphery of the small diameter portion 13a of the bottom cap 13. The inner periphery is the fixed end and the outer periphery is the free end, and the outer periphery is allowed to bend. The leaf valve 14 in this embodiment is composed of three elastic annular plates 14a, 14b, and 14c stacked together, and the outer diameter of the central annular plate 14b among the annular plates 14a, 14b, and 14c is larger than the outer diameters of the annular plates 14a and 14c located at both the upper and lower ends and is slightly smaller than the inner diameter of the annular opposing seat portion 15b of the valve seat member 15. The number of annular plates constituting the leaf valve 14 can be set arbitrarily according to the damping force desired to be obtained by the damper D, and may be a single number instead of a plurality of plates.

Annular spacers 31, 32 are stacked on the top and bottom of the leaf valve 14 in FIG. 2, and are immovably attached to the outer periphery of the small diameter portion 13a of the bottom cap 13. In this embodiment, the leaf valve 14 has an inner periphery sandwiched between spacers 31, 32 having a diameter smaller than the outer diameter of each annular plate 14a, 14b, 14c of the leaf valve 14, so that the outer periphery can bend elastically in the vertical direction in FIG. 2 with the outer periphery of the spacers 31, 32 as a fulcrum. Note that although the spacer 31 is made of a single annular plate, it may be made of multiple annular plates, and although the spacer 32 is made of multiple annular plates as shown in the figure, it may be made of a single ring.

The outer diameter of the valve stopper 30, which is disposed on the counter-pressure chamber side of the spacer 31, is larger than the outer diameter of the spacer 31 and smaller than the outer diameter of the lowermost annular plate 14c in FIG. 2 among the annular plates 14a, 14b, and 14c of the leaf valve 14. When the leaf valve 14 bends downward in FIG. 2 by more than a predetermined amount, the valve stopper 30 comes into contact with the leaf valve 14 to restrict the bending of the leaf valve 14.

The valve seat member 15 is cylindrical and has a cylindrical portion 15a that faces the outer periphery of the cylinder 10, has an opposing seat portion 15b on its inner periphery, and has a seal ring 15c attached to its outer periphery, and a partition wall portion 15d that is annular and fits onto the outer periphery of the small diameter portion 13a, is connected to the inner periphery of the cylindrical portion 15a, and has a port 15e. The valve seat member 15 is attached to the outer periphery of the small diameter portion 13a in the bottom cap 13 as an axial member, and the seal ring 15c attached to the outer periphery of the cylindrical portion 15a is in close contact with the inner periphery of the cylinder 10 and above the through hole 10a in FIG. 2, dividing the inside of the cylinder 10 into a pressure side chamber R2 as an operating chamber and a liquid chamber L as an operating chamber that is below the pressure side chamber R2 in FIG. 2 and communicates with the liquid reservoir chamber R via the through hole 10a.

The cylindrical portion 15a is provided with a thick portion 15f having an annular groove 15g on the outer periphery of which a seal ring 15c is fitted, a thin portion 15h having a thickness thinner than that of the thick portion 15f and an outer periphery flush with the outer periphery of the thick portion 15f, and an annular opposing seat portion 15b protruding radially inward from the inner periphery of the thin portion 15h. The seal ring 15c inserted in the annular groove 15g on the outer periphery of the cylindrical portion 15a has an outer diameter larger than the inner diameter of the cylinder 10, and when the valve seat member 15 is inserted into the cylinder 10, it is reduced in diameter and comes into close contact with the cylinder 10 to seal between the cylinder 10 and the cylindrical portion 15a. In addition, the outer diameter of the cylindrical portion 15a is slightly smaller than the inner diameter of the cylinder 10, and there is radial play between the valve seat member 15 and the cylinder 10, so when the valve seat member 15 is inserted into the cylinder 10, the valve seat member 15 can be displaced radially relative to the cylinder 10 by the amount of play. In this way, the outer diameter of the valve seat member 15 is set to a diameter that allows the valve seat member 15 to be displaced radially within the cylinder 10.

As described above, the opposing seat 15b in the cylindrical portion 15a of the valve seat member 15 and the mounting portion of the seal ring 15c relative to the cylindrical portion 15a are offset in the axial direction, so that even if the seal ring 15c is mounted on the cylindrical portion 15a, the inner diameter of the opposing seat 15b can be kept large, and the installation of the seal ring 15c can prevent the inner diameter of the opposing seat 15b from becoming smaller. In this embodiment, the mounting portion of the seal ring 15c relative to the opposing seat 15b in the cylindrical portion 15a of the valve seat member 15 is offset in the axial direction toward the compression side chamber R2.

The partition wall 15d is connected to the inner circumference of the end of the thick portion 15f of the cylindrical portion 15a on the side of the thin portion 15h, and the opposing seat portion 15b is provided on the inner circumference of the end of the thin portion 15h on the side opposite to the thick portion. The partition wall 15d has a port 15e that connects the pressure side chamber R2 to the liquid chamber L. Therefore, the pressure side chamber R2 is connected to the liquid reservoir chamber R via the port 15e, the liquid chamber L, and the through hole 10a. In this way, a passage A is provided that connects the pressure side chamber R2 to the liquid reservoir chamber R via the port 15e.

When the valve seat member 15 is configured as described above, there is no member that faces the outer periphery of the leaf valve 14 in the axial direction on the liquid chamber L side, which is the side opposite the partition wall of the leaf valve 14, and the leaf valve 14 can flex freely except for the restriction by the valve stopper 30. Furthermore, when the valve seat member 15 is configured in this manner, the opposing seat portion 15b and the partition wall portion 15d are positioned in an axially offset manner sufficient to ensure at least enough space for the leaf valve 14 to flex sufficiently, so that even if the leaf valve 14 flexes toward the partition wall portion 15d, the flexure is not hindered by the partition wall portion 15d. In addition, when the partition wall portion 15d is connected to the inner circumference of the end of the thick portion 15f on the thin portion 15h side of the cylindrical portion 15a, the nut 33 screwed to the small diameter portion 13a can be accommodated on the inner circumference of the thick portion 15f, so the overall length of the valve assembly in which the leaf valve 14, the valve seat member 15, the valve stopper 30, the spacers 31, 32, and the small diameter portion 13a are assembled can be shortened compared to when the partition wall portion 15d is connected to the inner circumference of the end of the thick portion 15f on the opposite side to the thin portion of the cylindrical portion 15a. However, the structure of the valve seat member 15 can be appropriately modified in design as long as the partition wall portion 15d is connected to the cylindrical portion 15a so as not to hinder the deflection of the leaf valve 14 relative to the opposing seat portion 15b, and is not limited to the structure shown in the figure.

When the valve seat member 15, together with the leaf valve 14, the valve stopper 30, and the spacers 31, 32, is assembled to the outer periphery of the small diameter portion 13a of the bottom cap 13, the leaf valve 14 faces the inner periphery of the opposing seat portion 15b of the valve seat member 15 with the outer periphery of the free end of the annular plate 14b in the axial center directly facing the inner periphery of the opposing seat portion 15b of the valve seat member 15 with a small predetermined annular gap P between them.

When the damper D is at rest and not expanding or contracting, the leaf valve 14 faces the inner peripheral surface of the facing seat 15b with the outer peripheral surface of the annular plate 14b facing the inner peripheral surface of the facing seat 15b without bending, with a predetermined annular gap P between them. In the damper D of this embodiment, the annular gap P between the opposing annular plate 14b and the facing seat 15b is very narrow. In this way, when the outer peripheral surface of the annular plate 14b faces the inner peripheral surface of the facing seat 15b without bending, the leaf valve 14 closes and minimizes the flow path area of the port 15e.

On the other hand, when the damper D starts to move (expands and contracts), the leaf valve 14 bends, and the amount of bending of the leaf valve 14 increases with the increase in the expansion/contraction speed. When the expansion speed of the damper D is close to 0 (zero), such as when the damper D starts to move, the amount of bending of the leaf valve 14 is very small, and the leaf valve 14 bends to such an extent that it cannot face the inner surface of the opposing seat 15b between the very low speed range and the low speed range, and the leaf valve 14 opens. Furthermore, when the expansion speed of the damper D is in the low speed range or the high speed range, the outer periphery of the leaf valve 14 bends significantly upward with the outer periphery of the spacer 32 as the fulcrum of bending. On the other hand, when the contraction speed of the damper D is in the low speed range or the high speed range, the outer periphery of the leaf valve 14 bends significantly downward with the outer periphery of the spacer 31 as the fulcrum of bending, and opens away from the opposing seat 15b. In this embodiment, passage A, which connects the pressure side chamber R2 and the liquid reservoir chamber R via port 15e, is opened and closed only by leaf valve 14.

If the annular gap P is set to approximately zero when the annular plate 14b faces the inner peripheral surface of the opposing seat 15b, a pressure difference will be generated between the compression side chamber R2 and the liquid chamber L as soon as the damper D starts to move, allowing the damper D to generate a damping force quickly when switching between expansion and contraction.

In addition, when the flow rate of the liquid flowing through the port 15e increases during the contraction operation of the damper D and the leaf valve 14 bends significantly, the valve stopper 30 located below the leaf valve 14 abuts against the lower end of the annular plate 14c in FIG. 2, restricting further bending of the leaf valve 14 downward in FIG. 2 and protecting the leaf valve 14.

The front fork F of this embodiment is configured as described above, and the operation of the front fork F will be described below. When the front fork F extends, the damper D also extends with the extension of the telescopic body 1. When the damper D extends, the piston 11 moves upward in FIG. 1 in the cylinder 10, contracting the extension side chamber R1 and expanding the compression side chamber R2. The liquid in the contracted extension side chamber R1 pushes open the extension side damping valve 16 and moves to the expanded compression side chamber R2 through the extension side damping passage 11a. Then, since the extension side damping valve 16 provides resistance to the flow of the liquid, the pressure in the extension side chamber R1 becomes higher than the pressure in the compression side chamber R2, and the damper D generates an extension side damping force that hinders the extension of the telescopic body 1. In the front fork F in this embodiment, a needle 24 is provided in the damping force adjustment passage DP that bypasses the extension side damping passage 11a and communicates between the extension side chamber R1 and the compression side chamber R2, and when the needle 24 opens the damping force adjustment passage DP, the liquid in the extension side chamber R1 passes through the damping force adjustment passage DP as well as the extension side damping passage 11a and moves to the compression side chamber R2 during the extension operation of the damper D. Therefore, by changing the flow area of the damping force adjustment passage DP, the damping force generated by the damper D during the extension operation can be adjusted. Also, during the extension operation of the front fork F, the piston rod 12 retreats from the cylinder 10 and there is a shortage of liquid in the compression side chamber R2, so the leaf valve 14 bends upward in FIG. 2 and opens, and the shortage of liquid is supplied from the liquid reservoir chamber R to the compression side chamber R2.

On the other hand, when the front fork F is contracted, the damper D is also contracted in accordance with the contraction of the telescopic body 1. When the damper D is contracted, the piston 11 moves downward in FIG. 1 in the cylinder 10, contracting the compression side chamber R2 and expanding the extension side chamber R1. The liquid in the contracted compression side chamber R2 pushes open the compression side check valve 17 and moves to the expanded extension side chamber R1 through the compression side passage 11b. Therefore, since the compression side check valve 17 provides almost no resistance to the flow of liquid, the pressure in the extension side chamber R1 and the pressure in the compression side chamber R2 become almost equal when the damper D is contracted. Also, when the front fork F is contracted, the piston rod 12 enters the cylinder 10 and the liquid becomes excessive in the cylinder 10, so the leaf valve 14 is bent downward in FIG. 2 and opens, and the excess liquid is discharged from the compression side chamber R2 to the liquid reservoir chamber R through the liquid chamber L. The leaf valve 14 provides resistance to the flow of liquid from the compression side chamber R2 to the liquid reservoir chamber R, so the pressure in the expansion side chamber R1 and the pressure in the expansion side chamber R2 both rise while remaining approximately equal. Because the pressure-receiving area on the compression side chamber R2 side of the piston 11 is larger than the pressure-receiving area on the expansion side chamber R1 side, the damper D generates a compression side damping force that prevents the contraction of the telescopic body 1 when the pressure in the expansion side chamber R1 and the pressure in the compression side chamber R2 rise.

When the piston speed of the damper D is in the very low speed range close to 0 during the contraction of the front fork F, the pressure in the compression side chamber R2 rises due to the piston rod 12 entering the cylinder 10, but the pressure difference with the pressure in the liquid chamber L does not reach the opening pressure of the leaf valve 14, so even if the leaf valve 14 bends, it faces the outer periphery within the axial width range of the inner circumference of the opposing seat 15b and is in a closed state, so the flow area of the annular gap P between the leaf valve 14 and the opposing seat 15b is kept extremely small. Furthermore, while the piston speed during the contraction of the damper D increases and changes from the very low speed range to the low speed range, the pressure difference between the pressure in the compression side chamber R2 and the pressure in the liquid chamber L exceeds the opening pressure of the leaf valve 14, so the leaf valve 14 bends and opens by moving its outer periphery downward in FIG. 2 from the axial width range of the inner circumference of the opposing seat 15b, increasing the flow area of the annular gap P between the leaf valve 14 and the opposing seat 15b.

Therefore, when the front fork F is contracted, the damping force characteristic of the damper D, which is the damping force characteristic generated by the damper D according to the piston speed, is such that the damping coefficient increases significantly as the piston speed increases, as shown in FIG. 3. After that, when the piston speed increases to a low speed range, the leaf valve 14 opens, and the damping force characteristic of the damper D becomes such that the damping coefficient becomes small. Furthermore, the piston speed during the contraction operation of the damper D increases to a medium speed range, and the flow rate of the liquid passing through the port 15e from the compression side chamber R2 to the liquid reservoir chamber R increases, but the leaf valve 14 bends downward significantly to further increase the flow area of the annular gap P, so that the damping force characteristic of the damper D becomes such that the damping coefficient remains small, as shown in FIG. 3. Furthermore, when the piston speed during the contraction operation of the damper D increases and reaches a high speed range, the leaf valve 14 bends significantly and abuts against the valve stopper 30, preventing further downward bending, so that the damping force characteristics of the damper D become characteristics that increase the damping coefficient, as shown in FIG. 3.

In the front fork F of this embodiment, the compression side chamber R2 and the liquid chamber L are connected through the bottom cap 13 without going through the port 15e, bypassing the passage A through the port 15e. A needle 18 that changes the flow path area is provided in the bottom cap 13. When the needle 18 opens the passage in the bottom cap 13, the liquid in the compression side chamber R2 moves to the liquid chamber L through the bottom cap 13 in addition to the port 15e when the damper D is contracted. Therefore, by changing the flow path area in the bottom cap 13, the damping force generated by the damper D when it is contracted can be adjusted.

As described above, the damper D of this embodiment includes a cylinder 10, a bottom cap (shaft member) 13 inserted into the cylinder 10, a leaf valve 14 that is annular and fixed at its inner periphery to the bottom cap (shaft member) 13, and is allowed to bend in the axial direction at its outer periphery, and a valve seat member 15 that is annular and attached to the bottom cap (shaft member) 13 to divide the inside of the cylinder 10 into a pressure side chamber (operating chamber) R2 and a liquid chamber (operating chamber) L, and has a port 15e that connects the pressure side chamber (operating chamber) R2 and the liquid chamber (operating chamber) L, and an opposing seat portion 15b on its inner periphery that faces the outer periphery of the leaf valve 14. The valve seat member 15 has an elastic seal ring 15c attached to its outer periphery and in close contact with the inner periphery of the cylinder 10.

The front fork F of this embodiment includes a telescopic body 1 having a vehicle body side tube 2 and a wheel side tube 3 that can move in the axial direction relative to the vehicle body side tube 2, and a damper D that is housed in the telescopic body 1 and expands and contracts together with the telescopic body 1 to generate a damping force. The damper D includes a cylinder 10, a bottom cap (shaft member) 13 inserted into the cylinder 10, a leaf valve 14 that is annular and fixed on the bottom cap (shaft member) 13 at its inner periphery to allow axial deflection on the outer periphery, a port 15e that is annular and attached to the bottom cap (shaft member) 13 to divide the inside of the cylinder 10 into a compression side chamber (operating chamber) R2 and a liquid chamber (operating chamber) L, and a valve seat member 15 that has an opposing seat portion 15b on its inner periphery that faces the outer periphery of the leaf valve 14, and the valve seat member 15 has an elastic seal ring 15c that is attached to its outer periphery and is in close contact with the inner periphery of the cylinder 10.

In the damper D and front fork F configured in this manner, the seal ring 15c can seal between the valve seat member 15 and the cylinder 10, so the inner diameter of the valve seat member 15 and the outer diameter of the leaf valve 14 can be made large, ensuring a large flow area when the leaf valve 14 flexes and shifts axially relative to the opposing seat portion 15b to open.

In this way, even with a damper D that cannot have a large cylinder diameter, or a front fork F that cannot structurally have a large cylinder 10 diameter because the damper D is housed in a small space inside the telescopic body 1, a large flow area can be secured between the leaf valve 14 and the opposing seat 15b, so that even if the damper D strokes at high speed and the flow rate of liquid passing between the leaf valve 14 and the opposing seat 15b increases, the resistance provided by the leaf valve 14 can be prevented from becoming excessive. Therefore, with the damper D and front fork F of this embodiment, it is possible to prevent the damping force from becoming excessive even when stroking at high speed, and the ride comfort of the saddle-type vehicle can be improved.

In addition, the valve seat member 15 may have the outer circumference other than the seal ring 15c abutted against the inner circumference of the cylinder 10, but in the front fork F of this embodiment, the outer diameter of the valve seat member 15 is set to a diameter that allows the valve seat member 15 to be displaced radially within the cylinder 10. In the front fork F configured in this manner, since there is radial play between the cylinder 10 and the valve seat member 15, even if the valve seat member 15, which is aligned with the bottom cap (shaft member) 13, is accommodated in the cylinder 10, the valve seat member 15 does not receive a large load from the cylinder 10 due to the fit other than receiving the elastic force of the seal ring 15c. Therefore, even if the inner diameter of the valve seat member 15 and the outer diameter of the leaf valve 14 are increased while sealing between the valve seat member 15 and the cylinder 10 with the seal ring 15c, the leaf valve 14 and the opposing seat portion 15b do not become axially misaligned. In addition, because there is radial play between the cylinder 10 and the valve seat member 15, when inserting the bottom cap (shaft member) 13 into the cylinder 10, the valve seat member 15 does not bite into the inner circumference of the cylinder 10, ensuring good workability.

Furthermore, in the front fork F of this embodiment, the damper D is provided with a piston rod 12 that is axially inserted into the cylinder 10 and connected to the vehicle body side tube 2, and a piston 11 that is axially inserted into the cylinder 10 and connected to the piston rod 12 and divides the inside of the cylinder 10 into an extension side chamber R1 and a compression side chamber R2. The cylinder 10 is connected to the wheel side tube 3, and the valve seat member 15 divides the inside of the cylinder 10 into two working chambers, the compression side chamber R2 and a liquid chamber L that is connected to the liquid reservoir chamber R inside the extension body 1 and outside the cylinder 10.

In the front fork F configured as above, when the damper D is contracted, the leaf valve 14 provides resistance when the liquid passes from the compression side chamber R2 to the liquid reservoir chamber R via the liquid chamber L. When the front fork F is contracted at high speed, the piston rod 12 enters the cylinder 10 and a large flow rate of liquid passes between the leaf valve 14 and the opposing seat 15b. However, since a large flow area can be secured between the leaf valve 14 and the opposing seat 15b, the compression side damping force is prevented from becoming excessive, and a good riding comfort can be achieved without the rider of the saddle-type vehicle perceiving a rough feeling. In addition, in the front fork F of this embodiment, the leaf valve 14 can bend in both axial directions relative to the opposing seat 15b, so that even when the front fork F is extended, the leaf valve 14 bends toward the compression side chamber R2 and opens, and the volume of liquid that the piston rod 12 withdraws from the cylinder 10 can be supplied from the liquid reservoir chamber R to the compression side chamber R2. The leaf valve 14 faces the opposing seat 15b without contacting it, and when it bends and shifts significantly in the axial direction from the opposing seat 15b, it can increase the flow passage area and reduce the resistance to the flow of liquid passing through it compared to a valve that directly sits on the valve seat, so it can also be used as a check valve that allows the flow of liquid from the liquid reservoir chamber R to the compression side chamber R2 when the front fork F is extended. Therefore, with the front fork F configured in this way, the leaf valve 14 can be used as a valve for generating damping force when the front fork F is contracted, and can also be used as a check valve when the front fork F is extended, so there is no need to install another valve, which reduces manufacturing costs and makes the front fork F lighter.

Furthermore, in the front fork F of this embodiment, the passage A that communicates the compression side chamber R2 and the liquid reservoir chamber R through the port 15e of the valve seat member 15 is opened and closed only by the leaf valve 14. With the front fork F configured in this manner, there is no valve in series with the leaf valve 14 for passage A. Therefore, even when the front fork F contracts at a very high speed, such as when a saddle-type vehicle (not shown) to which the front fork F is applied runs over a large step while traveling on an unpaved road (off-road) called gravel or dirt, the leaf valve 14 bends and opens significantly, ensuring a large flow area in passage A. This prevents the damper D from generating excessive damping force, and the front fork F contracts quickly to absorb the impact and improve the ride comfort of the vehicle.

In the front fork F of this embodiment, a valve stopper 30 is provided to restrict the deflection of the leaf valve 14 toward the liquid chamber L. This provides a damping force characteristic that restricts the deflection of the leaf valve 14 and increases the damping coefficient when the piston speed during the contraction operation of the damper D reaches a high speed range, thereby preventing bottoming out due to maximum contraction of the front fork F and protecting the leaf valve 14. However, if not required, the valve stopper 30 may be omitted.

In the front fork F of this embodiment, the valve seat member 15 divides the working chamber into a compression side chamber R2 and a liquid chamber L, and the leaf valve 14 provides resistance to the flow of liquid that exchanges between the compression side chamber R2 and the liquid chamber L. However, the leaf valve 14 and the valve seat member 15 may be attached to the piston rod 12 together with the piston 11 or instead of the piston 11 to form the working chamber into an expansion side chamber R1 and a compression side chamber R2, and the leaf valve 14 may provide resistance to the flow of liquid that exchanges between the expansion side chamber R1 and the compression side chamber R2. In this case, the inner diameter of the opposing seat portion 15b in the valve seat member 15 and the outer diameter of the leaf valve 14 can be increased to ensure a large flow area between the opposing seat portion 15b and the leaf valve 14, so that excessive damping force can be suppressed even when stroking at high speed, and the riding comfort of the saddle-type vehicle can be improved. In this case, the piston rod 12 inserted into the cylinder 10 serves as an axial member to hold the leaf valve 14 and the valve seat member 15.

In addition, in the front fork F of this embodiment, the cylinder 10 is connected to the wheel side tube 3 and the piston rod 12 is connected to the vehicle body side tube 2, but the cylinder 10 may be connected to the vehicle body side tube 2 and the piston rod 12 may be connected to the wheel side tube 3.

Furthermore, in the front fork F of this embodiment, the mounting portion of the seal ring 15c on the valve seat member 15 is offset in the axial direction from the opposing seat portion 15b on the valve seat member 15. With the front fork F configured in this manner, the valve seat member 15 has a portion (thin portion 15h on the cylindrical portion 15a) that axially avoids the mounting portion (thick portion 15f on the cylindrical portion 15a) that must be thickened to face the cylinder 10 in order to mount the seal ring 15c on the outer periphery. This makes it easier to ensure a flow area between the leaf valve 14 and the opposing seat portion 15b by increasing the inner diameter of the opposing seat portion 15b compared to when the opposing seat portion 15b is provided on the inner periphery of the mounting portion (thick portion 15f on the cylindrical portion 15a).

In addition, in the front fork F of this embodiment, the mounting portion of the seal ring 15c in the valve seat member 15 (thick portion 15f in the tubular portion 15a) is shifted toward the compression side chamber R2 side in the axial direction with respect to the opposing seat portion 15b in the valve seat member 15. In the front fork F configured in this manner, when the valve seat member 15 divides the compression side chamber R2 and the liquid chamber L in the cylinder 10, the leaf valve 14 bends toward the liquid chamber L side opposite the mounting portion (thick portion 15f in the tubular portion 15a) that must be thickened to face the cylinder 10 in order to mount the seal ring 15c on the outer periphery when the damper D contracts, so that the leaf valve 14 does not interfere with the mounting portion (thick portion 15f in the tubular portion 15a). Therefore, according to the front fork F configured in this manner, the leaf valve 14 is not interfered with by the mounting portion (thick portion 15f in the tubular portion 15a) during the contraction operation, so that it is easy to ensure a large flow passage area between the leaf valve 14 and the opposing seat portion 15b.

In the front fork F of this embodiment, the valve seat member 15 is cylindrical and faces the outer periphery of the cylinder 10. The valve seat member 15 is provided with a cylindrical portion 15a having an opposing seat portion 15b on its inner periphery and a seal ring 15c attached to its outer periphery, and a partition portion 15d having an annular shape, which is fitted to the outer periphery of the bottom cap (shaft member) 13, is connected to the inner periphery of the cylindrical portion 15a, and has a port 15e. The partition portion 15d is shifted toward the compression side chamber R2 in the axial direction relative to the opposing seat portion 15b. In the front fork F configured in this manner, when the valve seat member 15 divides the compression side chamber R2 and the liquid chamber L in the cylinder 10, when the damper D contracts, the leaf valve 14 bends toward the liquid chamber L on the opposite side to the partition portion 15d disposed between the compression side chamber R2 and the liquid chamber L, so that the leaf valve 14 does not interfere with the partition portion 15d. Therefore, with a front fork F configured in this manner, the leaf valve 14 is not interfered with by the partition wall 15d during contraction, making it easier to ensure a large flow area between the leaf valve 14 and the opposing seat 15b.

In the front fork F of this embodiment, the shaft member is the bottom cap 13, but as described above, the shaft member may be the piston rod 12 to which the leaf valve 14 and the valve seat member 15 are attached, or the shaft member may be a separate part from the bottom cap 13 that closes the end of the cylinder 10 and attached to the bottom cap 13, or may be provided separately from the bottom cap 13. In other words, the shaft member may be a member that is inserted into the cylinder 10 and to which the leaf valve 14 and the valve seat member 15 are attached.

The specific configuration of the damper D described above is an example, and the design can be modified as appropriate without departing from the scope of the claims. Furthermore, in explaining the damping force characteristics of the damper D in the front fork F of this embodiment, the piston speed is divided into a very low speed range, a low speed range, a medium speed range, and a high speed range, but the speeds that divide the speed ranges can be set arbitrarily by the designer.

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

1: Telescopic body, 2: Vehicle body side tube, 3: Wheel side tube, 10: Cylinder, 11: Piston, 12: Piston rod, 13: Bottom cap (shaft member), 14: Leaf valve, 15: Valve seat member, 15a: Cylinder portion, 15b: Opposing seat portion, 15c: Seal ring, 15d: Partition portion, 15e: Port, 15f: Thick portion (mounting portion),
F: front fork, D: damper, L: fluid chamber (operating chamber), R: fluid reservoir chamber, R2: compression side chamber (operating chamber)

Claims (8)

A cylinder;
A shaft member that is inserted into the cylinder;
a leaf valve having an annular shape, an inner circumferential side of which is fixed to the shaft member and an outer circumferential side of which is allowed to bend in the axial direction;
a valve seat member having an annular shape, attached to the shaft member to divide the inside of the cylinder into two working chambers, the valve seat member having a port communicating between the working chambers and an opposing seat portion on an inner periphery thereof facing an outer periphery of the leaf valve,
The damper, wherein the valve seat member has an elastic seal ring attached to an outer periphery thereof and in close contact with an inner periphery of the cylinder. a telescopic body having a vehicle body side tube and a wheel side tube that is axially movable relative to the vehicle body side tube;
a damper that is housed in the telescopic body and expands and contracts together with the telescopic body to generate a damping force,
the damper comprises a cylinder, a shaft member inserted into the cylinder, a leaf valve having an annular shape and an inner circumferential side fixed to the shaft member and allowing an outer circumferential side to bend in the axial direction, and a valve seat member having an annular shape attached to the shaft member to divide the inside of the cylinder into two working chambers, the valve seat member having a port communicating between the working chambers and an opposing seat portion on an inner circumferential side opposing an outer circumferential side of the leaf valve,
The front fork, wherein the valve seat member has an elastic seal ring attached to an outer periphery of the cylinder and in close contact with an inner periphery of the cylinder. 3. The front fork according to claim 2, wherein an outer diameter of the valve seat member is set to a diameter that allows radial displacement of the valve seat member within the cylinder. The damper is
a piston rod that is inserted into the cylinder so as to be axially movable and that is connected to the vehicle body side tube;
a piston that is movably inserted into the cylinder and connected to the piston rod and divides the inside of the cylinder into an extension-side chamber and a compression-side chamber,
The cylinder is connected to the wheel side tube,
3. The front fork according to claim 2, wherein the valve seat member divides the inside of the cylinder into two working chambers, namely, the compression side chamber and a fluid chamber that is in the telescopic body and communicates with a fluid reservoir chamber outside the cylinder. 5. The front fork according to claim 4, wherein a passage that communicates between the compression side chamber and the fluid reservoir chamber via the port of the valve seat member is opened and closed only by the leaf valve. 6. The front fork according to claim 2, wherein a mounting portion of the valve seat member, to which the seal ring is attached, is shifted in the axial direction with respect to the opposing seat portion of the valve seat member. 6. The front fork according to claim 4, wherein a mounting portion of the valve seat member, to which the seal ring is attached, is shifted toward the compression side chamber in the axial direction with respect to the opposing seat portion of the valve seat member. The valve seat member is
a cylindrical portion having an inner periphery on which the opposing seat portion is provided and on which the seal ring is attached;
a partition wall portion having the port and an annular shape and fitted to an outer periphery of the shaft member and connected to an inner periphery of the cylindrical portion,
The front fork according to claim 4 or 5, wherein the partition portion is offset toward the compression side chamber in the axial direction with respect to the opposing seat portion.

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