Damper and front fork

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

[Technical field]

[0001] The present invention relates to a damper and a front fork. [Background technology]

[0002] 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 inserted axially slidably into the outer tube, and a damper 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 extends or retracts during travel, the damper generates a damping force to suppress vibrations of the vehicle body and improve the ride comfort of the vehicle.

[0003] In saddle-type vehicles, compared to four-wheeled automobiles, the front wheels are displaced significantly relative to the vehicle body when starting, braking, or driving on rough roads, which can cause the damper installed in the front fork to stroke at high speed, resulting in a large amount of hydraulic oil passing through the damping valve in the damper and resulting in excessive damping force.

[0004] There is a damping valve that is used in four-wheeled automobiles, which is capable of suppressing vibration of the vehicle body while suppressing excessive damping force by increasing the damping coefficient when the stroke speed is low and decreasing the damping coefficient when the stroke speed is high. This damping valve, for example, has an annular leaf valve whose inner periphery is fixed to a piston rod and is allowed to bend on the outer periphery, and an annular valve case fixed to the piston rod, and 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 valve case and the cylinder rising from the outer periphery of the port (for example, see Patent Document 1).

[0005] The above-mentioned damping valve exerts a damping force characteristic in which, 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 that the damping force rises sharply according 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 the 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. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-183918 A Summary of the Invention [Problem to be solved by the invention]

[0007] 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 makes it necessary to increase the flow path area when the leaf valve bends and moves axially away from the opposing seat.

[0008] However, conventional damping valves have a structure in which the cylindrical portion of the valve case fixed to the piston rod faces the cylinder with a sufficiently large gap so as not to interfere with the cylinder, and since 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 path area when the leaf valve bends and moves axially away from the opposing seat portion.

[0009] Therefore, even if a conventional damping valve is applied as it is to a front fork damper, an excessive damping force is generated when the damper strokes at high speed, making it difficult to improve the riding comfort of a saddle-type vehicle.

[0010] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a damper and a front fork that can prevent the damping force from becoming excessive even when stroking at high speed. [Means for solving the problem]

[0011] In order to solve the above problems, the damper of the present invention comprises a cylinder, a shaft member inserted into the cylinder, a ring-shaped leaf valve whose inner circumference is fixed to the shaft member and whose outer circumference is allowed to deflect in the axial direction, and a ring-shaped valve seat member attached to the shaft member to divide the inside of the cylinder into two working chambers and having a port connecting the working chambers and an opposing seat on its inner circumference that faces the outer circumference of the leaf valve, and the valve seat member has an elastic seal ring attached to the outer circumference and in close contact with the inner circumference of the cylinder.

[0012] Furthermore, in order to solve the above problems, the front fork of the present invention comprises a telescopic body having a vehicle body side tube and a wheel side tube that is movable in the axial direction relative to the vehicle body side tube, and a damper that is housed within the telescopic body and expands and contracts together with the telescopic body to generate a damping force, the damper comprising a cylinder, a shaft member inserted into the cylinder, a ring-shaped leaf valve whose inner periphery is fixed to the shaft member and whose outer periphery is allowed to deflect in the axial direction, and a valve seat member that is ring-shaped and attached to the shaft member, dividing the inside of the cylinder into two working chambers, and has a port that communicates between the working chambers, and a valve seat member on its inner periphery that faces the outer periphery of the leaf valve, and the valve seat member has an elastic seal ring that is attached to the outer periphery and comes into close contact with the inner periphery of the cylinder.

[0013] In the damper and front fork configured in this manner, the seal ring can seal between the valve seat member and the cylinder, so that the inner diameter of the valve seat member and the outer diameter of the leaf valve can be made large, ensuring a large flow path area when the leaf valve flexes and shifts axially relative to the annular valve seat to open.

[0014] 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 inside the cylinder. In the front fork configured in this manner, since there is a radial play between the cylinder and the valve seat member, even if the valve seat member that is aligned with the shaft member is accommodated in the cylinder, the valve seat member does not receive a large load from the cylinder due to the fitting 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. Furthermore, since there is a 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.

[0015] Also, in the front fork, the damper may include a piston rod movably inserted into the cylinder in the axial direction and connected to a vehicle body side tube, and a piston movably inserted into the cylinder and connected to the piston rod, dividing the inside of the cylinder into an extension side chamber and a compression side chamber, the cylinder being connected to the wheel side tube, and the valve seat member may divide the inside of the cylinder into two working chambers, the compression side chamber and a liquid chamber inside the extension / contraction body and connected to a liquid reservoir chamber outside the cylinder.

[0016] With a front fork configured in this manner, 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 any other valves, reducing manufacturing costs and making the front fork lighter.

[0017] Furthermore, in the front fork, the passage that communicates 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 manner, since there is no valve in series with the leaf valve for the passage, 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 an unpaved road (off-road) called gravel or dirt, the leaf valve bends significantly and opens, ensuring a large flow passage area in the passage, and the damper does not generate excessive damping force, so that the front fork contracts quickly to absorb shock and improve the ride comfort of the vehicle.

[0018] 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 this front fork configured as above, the valve seat member can be provided with a portion for forming the opposing seat portion that is axially avoided from the mounting portion that faces the cylinder and must be thickened in order to mount the seal ring on its outer periphery, so that it is 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 a case in which the opposing seat portion is provided on the inner periphery of the mounting portion.

[0019] In the front fork, the mounting portion of the seal ring on the valve seat member may be shifted toward the compression side chamber in the axial direction 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 that must be thickened to face the cylinder in order to mount the seal ring on its outer periphery when the damper is contracted, so that 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 path area between the leaf valve and the opposing seat portion.

[0020] In the front fork, the valve seat member includes a cylindrical portion that faces the outer periphery of the cylinder, has an opposing seat portion on its inner periphery, and has a seal ring attached to its outer periphery, and a partition portion that is annular, fits onto the outer periphery of the shaft member, is connected to the inner periphery of the cylindrical portion, and has a port, and the partition portion may be shifted axially toward the compression side chamber from the opposing seat portion. In the front fork configured in this manner, 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 portion disposed between the compression side chamber and the liquid chamber, so that the leaf valve does not interfere with the partition portion. Therefore, with the front fork configured in this manner, the leaf valve is not interfered with by the partition portion during contraction, so that it is easy to ensure a large flow passage area between the leaf valve and the opposing seat portion. Effect of the Invention

[0021] According to the damper and front fork of the present invention, the damping force can be prevented from becoming excessive even when stroking at high speed. [Brief description of the drawings]

[0022] [Figure 1] 1 is a vertical cross-sectional view of a damper and a front fork according to an embodiment of the present invention; [Diagram 2] 2 is a partially enlarged cross-sectional view of the damper and the front fork according to the embodiment of the present invention. FIG. [Diagram 3] 5 is a diagram showing damping force characteristics in a damper and a front fork according to an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention will be described below based on the embodiment shown in the drawings. As shown in Fig. 1, a front fork F in one embodiment is configured to include a telescopic body 1 having a vehicle body side tube 2 and a wheel side tube 3 and capable of extending and retracting, and a damper D housed in 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.

[0024] 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 capable of telescopic movement. 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.

[0025] The wheel side tube 3 is inserted into the vehicle body side tube 2 from below the vehicle body side tube 2, and can move in the axial direction relative to the vehicle body side tube 2. An annular bush 7 and an annular seal member 8 are provided on the inner periphery of the lower end of the vehicle body side tube 2, which come into sliding contact with the outer periphery of the wheel side tube 3, and an annular bush 9 is attached to the outer periphery of the upper end of the wheel side tube 3, which comes into sliding contact with the inner periphery of the vehicle body side tube 2. The bushes 7 and 9 therefore allow the vehicle body side tube 2 and the wheel side tube 3 to move in the axial direction without any axial wobble relative to each other.

[0026] 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.

[0027] The lower end of the wheel side tube 3 is closed by an axle bracket 5 (not shown) that holds the axle of the front wheel, and the telescopic body 1 is connected to the front wheel by the axle bracket 5. The interior of the telescopic body 1 configured in this manner is a space sealed from the outside by a seal member 8. The axle bracket 5 includes a tubular 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 tubular 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 tubular portion 5a with an axial gap therebetween. 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 on the tubular portion 5a of the axle bracket 5 above the step portion 5c on the upper side 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.

[0028] 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.

[0029] The damper D is housed in the telescopic body 1. The damper D of this embodiment includes a cylinder 10 connected to the wheel-side tube 3 via an axle bracket 5, a piston 11 inserted axially movably 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 movably into the cylinder 10 and having an upper end connected to the vehicle-body-side tube 2 via the cap 4 and a lower side connected to the piston 11, a bottom cap 13 as a shaft member inserted into the cylinder 10 from the lower end in FIG. 1 which is the wheel-side tube side end of the cylinder 10, and a leaf valve 14 and a valve seat member 15 attached to the bottom cap 13.

[0030] The space outside the damper D is filled with liquid and gas, and serves as a liquid reservoir chamber R for storing the liquid.

[0031] Each part of the damper D will be described below. The cylinder 10 is screwed to a bottom cap 13 as 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. An annular rod guide 20 is attached to the upper open end of the cylinder 10. The rod guide 20 has a guide portion 20a that is annular and 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.

[0032] 1 of the case portion 20b of the rod guide 20 and the cap 4. The suspension spring 21 biases the vehicle body side tube 2 and the wheel side tube 3 in a direction that separates them from each other in the axial direction, that is, in a direction that extends the telescopic body 1, and elastically supports the vehicle body, which is interposed between the vehicle body and the front wheel of the saddle-ride type vehicle with the front fork F.

[0033] The piston rod 12 includes a cylindrical piston rod main body 22 and a cylindrical piston retaining rod 23 connected to the lower end of the piston rod main body 22 to retain the piston 11. The upper end of the piston rod 12 is connected to the inner periphery 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 periphery of the rod guide 20. The piston rod 12 can move relatively together with the piston 11 in the up and down direction in FIG. 1, which is the axial direction, with its radial movement restricted by the rod guide 20 and the piston 11.

[0034] 1, the piston rod 12 includes a large-diameter cylindrical portion 23a having a large outer diameter, which is screwed to the outer periphery of the lower end of the piston rod body 22, and a small-diameter cylindrical portion 23b having a small outer diameter, to which the piston 11 is attached. The piston rod 23 includes a hole 23c that communicates the inside and outside of the large-diameter cylindrical portion 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. The piston rod 23 further includes 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.

[0035] A control rod 25 interposed between the adjuster 6 screwed into the cap 4 and the needle 24 is inserted into the piston rod body 22 so as to be movable in the axial direction. 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.

[0036] In addition, an annular lock piece 26 is provided on the outer periphery of the piston rod body 22, which 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.

[0037] The piston 11 is annular and is fitted to 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 sandwiched 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 is in contact with the inner periphery of the cylinder 10, and divides the inside of the cylinder 10 into an expansion side chamber R1 and a compression side chamber R2, each of which is filled with liquid. The piston 11 further includes an expansion side damping passage 11a and a compression side passage 11b that communicate the expansion side chamber R1 and the compression side chamber R2 in parallel.

[0038] 1, which is the compression side chamber side 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 a plurality of 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 bending on the outer periphery side. Therefore, when the extension side damping valve 16 is bent by receiving 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 expansion side damping valve 16 sets the expansion side damping passage 11a as a one-way passage that allows only the flow of liquid from the expansion side chamber R1 to the compression side chamber R2.

[0039] 1, which is the end of the piston 11 on the side of the expansion side chamber, 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 expansion side chamber R1. The compression side check valve 17 is configured with an annular plate that is axially movably attached to 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. When the compression side check valve 17 is separated from the piston 11, it opens the compression side passage 11b, and when it is seated on the piston 11, it closes the compression side passage 11b. 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 expansion side chamber R1. Although the pressure-side valve is described above as pressure-side check valve 17, it may be a damping valve that provides resistance to the flow of liquid passing through.

[0040] The bottom cap 13 that fixes the cylinder 10 to the axle bracket 5 functions as an axial member and is cylindrical. It is equipped with a small diameter portion 13a that holds the leaf valve 14 and the valve seat member 15 from the upper end side in FIG. 2, which is the tip side, a medium diameter portion 13b that is connected to the lower end of the small diameter portion 13a in FIG. 2 and has an outer diameter larger than that of the small diameter portion 13a, a large diameter portion 13c that is connected to the lower end of the medium diameter portion 13b in FIG. 2 and has an outer diameter larger than that of the medium diameter portion 13b, and a flange portion 13d provided on the outer periphery of the lower end of the large diameter portion 13c in FIG. 2.

[0041] 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 periphery of the annular protrusion 5d provided on the inner periphery 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.

[0042] 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 hold the annular protrusion 5d of the axle bracket 5 between them, 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.

[0043] 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 communicates with a through hole 10a provided in the cylinder 10, and the pressure side chamber R2 communicates with 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 having a conical valve body at its tip is screwed to the inner periphery of the bottom cap 13. The needle 18 can be moved in the axial direction within the bottom cap 13 by a rotating operation, and can be moved toward or away from an annular valve seat 13e provided on the inner periphery of the bottom cap 13 to adjust the size of the flow path area between the annular valve seat 13e.

[0044] An annular valve stopper 30, an annular spacer 31, an annular leaf valve 14, an annular spacer 32, and an annular valve seat member 15 are assembled in this order onto the outer periphery of the small diameter portion 13a of the bottom cap 13 that is inserted into the cylinder 10, and the valve stopper 30, the spacer 31, the leaf valve 14, the spacer 32, and the valve seat member 15 are clamped between a nut 33 that is screwed onto 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, and are fixed to the bottom cap 13. In this way, the bottom cap 13 is inserted into the cylinder 10 and functions as a shaft member that holds the leaf valve 14 and the valve seat member 15.

[0045] As shown in Fig. 2, the leaf valve 14 is annular, and its 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 a fixed end and the outer periphery is a free end, and the outer periphery, which is the free end, is allowed to bend. The leaf valve 14 of this embodiment is configured by stacking three elastic annular plates 14a, 14b, and 14c, 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 to be obtained by the damper D, and may be a single number instead of a plurality of plates.

[0046] Annular spacers 31, 32 are stacked above and below 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 the spacers 31, 32 having a diameter smaller than the outer diameters of the annular plates 14a, 14b, 14c of the leaf valve 14, so that the outer periphery can be elastically deformed and bent 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 one 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 one ring.

[0047] In addition, the outer diameter of the valve stopper 30 disposed on the counter-pressure side 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, 14c of the leaf valve 14. Then, the valve stopper 30 comes into contact with the leaf valve 14 to regulate the bending of the leaf valve 14 when the leaf valve 14 bends downward in Fig. 2 by more than a predetermined amount.

[0048] 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 of the bottom cap 13 as a shaft 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 a working chamber and a liquid chamber L as a working 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.

[0049] The cylindrical portion 15a is provided with a thick portion 15f having a thick wall on the pressure side chamber side at the top in Fig. 2 and an annular groove 15g on the outer periphery of which a seal ring 15c is fitted, a thin portion 15h having a thinner wall than 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, since 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, when the valve seat member 15 is inserted into the cylinder 10, the valve seat member 15 can be displaced in the radial direction 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 in the radial direction within the cylinder 10.

[0050] As described above, the opposed seat portion 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 shifted in the axial direction, and even if the seal ring 15c is mounted on the cylindrical portion 15a, the inner diameter of the opposed seat portion 15b can be secured to be large, and the installation of the seal ring 15c can prevent the inner diameter of the opposed seat portion 15b from becoming smaller. In this embodiment, the mounting portion of the seal ring 15c relative to the opposed seat portion 15b in the cylindrical portion 15a of the valve seat member 15 is shifted toward the compression side chamber R2 in the axial direction.

[0051] The partition wall portion 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 opposite to the thick portion. The partition wall portion 15d has a port 15e that communicates the pressure side chamber R2 with the liquid chamber L. Therefore, the pressure side chamber R2 communicates with 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 communicates the pressure side chamber R2 with the liquid reservoir chamber R via the port 15e.

[0052] 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 being restricted by the valve stopper 30. Furthermore, when the valve seat member 15 is configured in this manner, the facing seat portion 15b and the partition wall portion 15d are positioned so as to ensure at least a space that allows the leaf valve 14 to flex sufficiently in the axial direction, so that even if the leaf valve 14 flexes towards the partition wall portion 15d, the flexure is not hindered by the partition wall portion 15d. When the partition wall portion 15d is connected to the inner periphery of the end of the thick-walled portion 15f on the thin-walled portion 15h side of the cylindrical portion 15a, the nut 33 screwed onto the small diameter portion 13a can be accommodated on the inner periphery of the thick-walled portion 15f, so that the overall length of the valve assembly in which the leaf valve 14, the valve seat member 15, the valve stopper 30, and the spacers 31, 32 are assembled to the small diameter portion 13a can be shortened compared to the case in which the partition wall portion 15d is connected to the inner periphery of the end of the thick-walled portion 15f on the opposite side to the thin-walled 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 bending of the leaf valve 14 relative to the opposing seat portion 15b, and is not limited to the structure shown in the figures.

[0053] 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 is opposed to 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 axially central annular plate 14b facing directly against the inner periphery of the opposing seat portion 15b with a predetermined small annular gap P therebetween.

[0054] When the damper D is at rest and not expanding or contracting, the leaf valve 14 faces the facing seat 15b with the outer circumferential surface of the annular plate 14b facing the inner circumferential surface of the facing seat 15b without bending, with a predetermined annular gap P between the facing seat 15b and the annular plate 14b. In the damper D of this embodiment, the annular gap P between the facing annular plate 14b and the facing seat 15b is very narrow. In this way, when the outer circumferential surface of the annular plate 14b faces the inner circumferential surface of the facing seat 15b without bending, the leaf valve 14 closes and minimizes the flow path area of ​​the port 15e.

[0055] 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 an 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 circumferential surface of the facing 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 moves away from the facing seat 15b to open. In this embodiment, the passage A that communicates between the pressure-side chamber R2 and the liquid reservoir chamber R via the port 15e is opened and closed by the leaf valve 14 alone.

[0056] Furthermore, if the annular gap P is made approximately zero when the annular plate 14b is directly facing the inner surface of the opposing seat portion 15b, a pressure difference will be generated between the compression side chamber R2 and the liquid chamber L immediately after the damper D starts to move, allowing the damper D to quickly generate a damping force when switching between expansion and contraction.

[0057] In addition, when the flow rate of liquid flowing through port 15e increases during the contraction operation of 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 to restrict further bending of the leaf valve 14 downward in FIG. 2 and protect the leaf valve 14.

[0058] 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, the extension side damping valve 16 provides resistance to the flow of the liquid, so that 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 for changing the flow path area 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. 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 path 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 the liquid in the compression side chamber R2 becomes insufficient, so the leaf valve 14 bends upward in FIG. 2 and opens, and the insufficient liquid is supplied from the liquid reservoir chamber R to the compression side chamber R2.

[0059] On the other hand, when the front fork F is contracted, the damper D is also contracted 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, the compression side check valve 17 hardly resists the flow of liquid, so that 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 that 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. Since the leaf valve 14 applies resistance to the flow of liquid from the compression-side chamber R2 to the liquid reservoir chamber R, the pressures in the expansion-side chamber R1 and the compression-side chamber R2 rise while maintaining a substantially equal state. Since 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 expandable body 1 when the pressures in the expansion-side chamber R1 and the compression-side chamber R2 rise.

[0060] When the piston speed of the damper D is in a 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 entry of the piston rod 12 into the cylinder 10, but the pressure difference with the pressure in the liquid chamber L does not reach the valve opening pressure of the leaf valve 14, so even if the leaf valve 14 bends, the outer circumferential surface faces the range of the axial width of the inner circumference of the facing seat 15b, and the leaf valve 14 is in a closed state, and the flow passage area of ​​the annular gap P between the leaf valve 14 and the facing 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 valve opening pressure of the leaf valve 14, so the leaf valve 14 bends and opens by moving the outer circumferential surface out of the range of the axial width of the inner circumference of the facing seat 15b downward in FIG. 2, and the flow passage area of ​​the annular gap P between the leaf valve 14 and the facing seat 15b is increased.

[0061] Therefore, when the front fork F is contracted, and the piston speed of the damper D during the contraction operation is near 0, the damping force characteristic, which is the characteristic of the damping force generated by the damper D according to the piston speed, becomes a characteristic in which the damping coefficient rises 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 a characteristic in which the damping coefficient becomes small. Furthermore, the piston speed during the contraction operation of the damper D increases to reach 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 path area of ​​the annular gap P, so that the damping force characteristic of the damper D becomes a characteristic in which the damping coefficient remains small, as shown in Fig. 3. Furthermore, when the piston speed during the contraction operation of 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. As a result, the damping force characteristic of damper D becomes a characteristic that increases the damping coefficient, as shown in FIG. 3.

[0062] In the front fork F of this embodiment, the compression side chamber R2 and the liquid chamber L are communicated through the bottom cap 13 without passing through the port 15e, bypassing the passage A via the port 15e, and a needle 18 for changing 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 contracting. Therefore, by changing the flow path area in the bottom cap 13, the damping force generated by the damper D when it is contracting can be adjusted.

[0063] 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 has its inner periphery fixed to the bottom cap (shaft member) 13 so as to be allowed to bend in the axial direction on 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 (working chamber) R2 and a liquid chamber (working chamber) L, and has a port 15e that connects the pressure side chamber (working chamber) R2 and the liquid chamber (working chamber) L, and 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 comes into close contact with the inner periphery of the cylinder 10.

[0064] 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 has an inner periphery fixed to the bottom cap (shaft member) 13 and is allowed to bend in the axial direction 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 having 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 the outer periphery and is in close contact with the inner periphery of the cylinder 10.

[0065] In the damper D and front fork F thus configured, the seal ring 15c can seal between the valve seat member 15 and the cylinder 10, so that the inner diameter of the valve seat member 15 and the outer diameter of the leaf valve 14 can be made large, and a large flow path area can be secured when the leaf valve 14 flexes and shifts axially relative to the opposing seat portion 15b to open.

[0066] In this way, even with the damper D whose cylinder diameter cannot be made large, or the front fork F whose cylinder 10 cannot be made large structurally because the damper D is housed in a narrow space inside the telescopic body 1, a large flow path area between the leaf valve 14 and the opposing seat 15b can be ensured, 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. Thus, with the damper D and front fork F of this embodiment, the damping force can be prevented from becoming excessive even when the damper strokes at high speed, and the ride comfort of the saddle-ride type vehicle can be improved.

[0067] The valve seat member 15 may have the outer circumference other than the seal ring 15c in contact with the inner circumference of the cylinder 10. However, 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 inside the cylinder 10. In the front fork F configured in this manner, since there is a 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 fitting, except for 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, since 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.

[0068] 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 telescopic body 1 and outside the cylinder 10.

[0069] 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 amount 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 riding 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 liquid of the volume of the piston rod 12 withdrawn 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 portion 15b without making contact with it, and when it bends and becomes significantly displaced in the axial direction from the opposing seat portion 15b, the flow passage area can be increased and the resistance to the flow of liquid passing through can be reduced compared to a valve that directly sits on the valve seat, so that 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 during the extension operation of the front fork F. Therefore, with the front fork F configured in this manner, the leaf valve 14 can be used as a valve for generating a damping force during the contraction operation of the front fork F and can also be used as a check valve during the extension operation of the front fork F, so there is no need to install any other valves, which allows the manufacturing costs to be reduced and the weight of the front fork F to be reduced.

[0070] 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 that is connected in series with the leaf valve 14 for the 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 significantly to open, thereby ensuring a large flow passage area in the passage A, and the damper D does not generate an excessive damping force, and the front fork F contracts quickly to absorb the impact and improve the ride comfort of the vehicle.

[0071] In the front fork F of this embodiment, a valve stopper 30 is provided to restrict the deflection of the leaf valve 14 towards 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 making it possible to prevent bottoming out due to maximum contraction of the front fork F and to protect the leaf valve 14. However, if not required, the valve stopper 30 may be omitted.

[0072] 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 communicates 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 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 communicates between the expansion side chamber R1 and the compression side chamber R2. In this case, too, the inner diameter of the opposing seat portion 15b of the valve seat member 15 and the outer diameter of the leaf valve 14 can be increased to ensure a large flow passage 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 a shaft member to hold the leaf valve 14 and the valve seat member 15.

[0073] 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.

[0074] Furthermore, in the front fork F of this embodiment, the mounting portion of the seal ring 15c in the valve seat member 15 is shifted in the axial direction with respect to the opposing seat portion 15b in the valve seat member 15. According to the front fork F configured in this manner, in the valve seat member 15, a portion (thin portion 15h in the cylindrical portion 15a) for forming the opposing seat portion 15b can be provided axially avoiding the mounting portion (thick portion 15f in 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. Therefore, compared to the case where the opposing seat portion 15b is provided on the inner periphery of the mounting portion (thick portion 15f in the cylindrical portion 15a), it is easier to ensure a flow passage area between the leaf valve 14 and the opposing seat portion 15b by increasing the inner diameter of the opposing seat portion 15b.

[0075] In the front fork F of this embodiment, the mounting portion (thick portion 15f in the tubular portion 15a) of the seal ring 15c in the valve seat member 15 is shifted toward the compression side chamber R2 side in the axial direction with respect to the opposing seat portion 15b of 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 to 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.

[0076] In the front fork F of this embodiment, the valve seat member 15 includes a cylindrical portion 15a that is cylindrical and 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 into 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, and the partition wall 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, the leaf valve 14 bends toward the liquid chamber L on the opposite side to the partition wall portion 15d disposed between the compression side chamber R2 and the liquid chamber L when the damper D contracts, so that the leaf valve 14 does not interfere with the partition wall portion 15d. Therefore, according to the front fork F configured in this manner, the leaf valve 14 is not interfered with by the partition portion 15d during the contracting operation, making it easier to ensure a large flow passage area between the leaf valve 14 and the opposing seat portion 15b.

[0077] 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 and the leaf valve 14 and the valve seat member 15 may be attached to the piston rod 12, 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 the shaft member may be provided separately from the bottom cap 13. In other words, the shaft member may be any member that is inserted into the cylinder 10 and onto which the leaf valve 14 and the valve seat member 15 are attached.

[0078] Moreover, the specific configuration of the damper D described above is merely an example, and the design can be appropriately modified 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 dividing the speed ranges can be set arbitrarily by the designer.

[0079] Although the preferred embodiment of the present invention has been described in detail above, modifications, variations and changes can be made without departing from the scope of the appended claims. [Explanation of symbols]

[0080] 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... cylindrical 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 (working chamber), R···Fluid reservoir chamber, R2···Pressure side chamber (working chamber)

Claims

1. A cylinder; a shaft member 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 interior 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 that faces an outer periphery of the leaf valve; The leaf valve opens when it is bent until it is no longer facing the opposing seat portion, The valve seat member has an elastic seal ring attached to the outer periphery thereof and tightly contacting the inner periphery of the cylinder. A damper characterized by:

2. an expandable 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, 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 an annular valve seat member attached to the shaft member to divide the interior 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 its inner periphery that faces the outer periphery of the leaf valve; The leaf valve opens when it is bent until it is no longer facing the opposing seat portion, The valve seat member has an elastic seal ring attached to the outer periphery thereof and tightly contacting the inner periphery of the cylinder. A front fork characterized by:

3. The outer diameter of the valve seat member is set to a diameter that allows the valve seat member to be displaced radially within the cylinder.

3. The front fork according to claim 2.

4. The damper is a piston rod inserted into the cylinder so as to be axially movable and connected to the vehicle body tube; a piston that is movably inserted into the cylinder and connected to the piston rod, and that divides the interior of the cylinder into an extension-side chamber and a compression-side chamber, The cylinder is connected to the wheel side tube, The valve seat member divides the inside of the cylinder into two working chambers, namely, the compression side chamber and a liquid chamber that is in the expansion and contraction body and communicates with a liquid reservoir chamber outside the cylinder.

3. The front fork according to claim 2.

5. The passage that communicates the pressure-side chamber and the liquid reservoir chamber via the port of the valve seat member is opened and closed only by the leaf valve.

5. The front fork according to claim 4.

6. The mounting portion of the seal ring on the valve seat member 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 2, wherein the front fork is a front fork with a spring.

7. The mounting portion of the seal ring on the valve seat member is shifted toward the compression-side chamber in the axial direction with respect to the opposing seat portion of the valve seat member.

6. The front fork according to claim 4 or 5.

8. The valve seat member is a cylindrical portion that is tubular and faces the inner periphery of the cylinder, has the opposing seat portion on its inner periphery, and has the seal ring attached to its outer periphery; a partition wall portion having the port and an annular shape, the partition wall portion being fitted onto an outer periphery of the shaft member and connected to an inner periphery of the cylindrical portion; The partition wall portion is offset toward the compression-side chamber in the axial direction with respect to the opposing seat portion.

6. The front fork according to claim 4 or 5.

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