Front fork

Abstract

A front fork (1) is provided with: a fork body (2) comprising a tube member (3) that includes a vehicle body-side tube (3a) and an axle-side tube (3b), and a suspension spring (4) that biases the tube member (3) in a stretching direction; a cap (5) which has a cylindrical part (5a) and a lid part (5b) connected to the outer circumference of the cylindrical part (5a) and which seals an opening end of the vehicle body-side tube (3a); a washer (6) which supports the upper end of the suspension spring (4); an adjuster (7) which comprises a shaft part (7a) to be screwed together with the washer (6), a flange part (7b) provided to the rear end of the shaft part (7a), and an operating shaft part 7c extending from a side, opposite to the shaft part side, of the flange part (7b) and which is rotatably inserted into the cylindrical part 5a; and a stopper member (8) which is mounted on the inner circumference of the cylindrical part (5a) and prevents the adjuster (7) from falling off the cap (5).

Description

[Technical field]

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

[0002] Some front forks that support the front wheel of a saddle riding vehicle are interposed between the vehicle body and the front wheel axle of the saddle riding vehicle to exert a damping force. Such front forks are generally configured with a fork body that expands and contracts and includes a body-side tube that is connected to the vehicle body of the saddle riding vehicle and an axle-side tube that fits into the body-side tube and is connected to the front wheel axle, a damper cartridge that includes a cylinder and a rod and is housed in the fork body to exert a damping force as the fork body expands and contracts, and a suspension spring that biases the damper cartridge and the fork body to expand.

[0003] The above-mentioned front fork may be equipped with an adjuster for adjusting the support position of the upper end of the suspension spring on a cap that closes the upper end of the vehicle body side tube so that the vehicle height of the saddle-riding vehicle can be adjusted to the user's desired vehicle height (see, for example, Patent Document 1).

[0004] In this front fork, the cap has an annular lid portion that is screwed into a female screw portion formed on the inner circumference of the tube on the vehicle body side, and a lid Part The damper cartridge has a cylindrical portion that hangs down from its inner periphery and has an opening on one side. The lower end of the cylindrical portion is connected to the rod of the damper cartridge, and a screw portion is provided on the inner periphery of the cylindrical portion above the opening.

[0005] On the other hand, the adjuster has a male screw portion on its outer periphery from the tip to the center that screws into the female screw portion of the cylindrical portion, and moves in and out of the cylindrical portion like a feed screw when rotated by the user. A C-ring is also attached to the outer periphery of the tip of the adjuster, and when the adjuster moves upward and out of the cylindrical portion when rotated and retreats to its maximum extent from the cylindrical portion, the C-ring comes into contact with the lower end of the female screw portion, restricting the adjuster from retreating any further.

[0006] The cylindrical portion contains a spring bearing that includes a main body that is inserted into the cylindrical portion and a spring support that extends from the main body and protrudes out of the cylindrical portion through the opening of the cylindrical portion and supports the upper end of the suspension spring, and the lower end of the adjuster abuts against the main body of the spring bearing. Therefore, when the user rotates the adjuster, the adjuster moves up and down relative to the cap, and the spring bearing follows the up and down movement of the adjuster to change the support position for the upper end of the suspension spring, thereby adjusting the vehicle height of the saddle-riding vehicle.

[0007] In this conventional front fork, when the user rotates the adjuster, it is displaced vertically relative to the cap. Therefore, in a saddle-ride vehicle with a layout in which the handlebars, instruments, etc. are located directly above the front fork, there is a possibility that the adjuster will interfere with the handlebars, instruments, etc.

[0008] Therefore, it is desirable to adopt a structure in which a screw hole is provided in the main body of the spring bearing and the spring bearing is screwed into the male screw portion of the adjuster, and the spring bearing alone is moved up and down relative to the cap in the manner of a feed screw by rotating the adjuster.

[0009] In this case, a flange is provided on the outer periphery of the adjuster, and the cap is constructed from two parts, with one of the parts that make up the cap supporting the adjuster flange from above to prevent the adjuster from coming loose.

[0010] Specifically, as shown in Fig. 6, the cap 100 is composed of a cover member 101 including an outer tube 101a screwed to the inner circumference of the vehicle body side tube 50, an inner tube 101b having a male thread portion 101c on its outer circumference, and an annular plate 101d connecting the outer tube 101a and the inner tube 101b, and a tube member 102 screwed to the outer circumference of the inner tube 101b of the cover member 101 and connected to the upper end of the rod 51. The adjuster 103 has a flange 103b on the outer circumference of the middle part and above the male thread portion 103a, and is rotatably inserted into the inner tube 101b of the cover member 101. The flange 103b of the adjuster 103 abuts against a step portion 101e formed on the inner circumference of the inner tube 101b, and is maintained in abutment against the step portion 101e of the inner tube 101b by the elastic force of the suspension spring 52. A male screw portion 103a of the adjuster 103 has a screw hole and is screwed into a spring bearing 104 that supports the upper end of the suspension spring 52. When the adjuster 103 is rotated, the spring bearing 104 moves up and down.

[0011] In a front fork configured in this manner, the adjuster 103 does not move up and down relative to the cap 100, so it can be used without difficulty in saddle-ride vehicles with a layout in which the handlebars, instruments, etc. are located directly above the front fork. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Patent Publication No. 2012-112452 Summary of the Invention [Problem to be solved by the invention]

[0013] However, in the above-mentioned front fork, the cap 100 is composed of two parts, the cover member 101 and the tubular member 102, which are connected by screw fastening, so that an overlapping margin must be secured in the screw fastening portion between the tubular member 102 and the inner tube 101b of the cover member 101.

[0014] Furthermore, since the opening 102a provided in the tubular member 102 and through which the spring support portion 104a of the spring bearing 104 is inserted needs to be provided downwardly to avoid the screw portion 102b of the tubular member 102, the overall length of the tubular member 102 inevitably becomes longer and the support position of the suspension spring 52 of the spring bearing 104 also shifts downward by that amount.

[0015] Then, if the support position of the suspension spring 52 on the spring bearing 104 is shifted downward, the axial length (storage length) of the space in which the suspension spring 52 is installed is shortened accordingly. If the storage length is shortened, the design freedom of the suspension spring 52 is accordingly reduced, which is a problem.

[0016] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a front fork which can shorten the overall length of the cap and improve the design freedom of the suspension spring. [Means for solving the problem]

[0017] In order to achieve the above object, the front fork of the present invention comprises a fork body having a tube member in which a vehicle body side tube and an axle side tube are slidably fitted together, and a suspension spring that biases the tube member in an extension direction, a tubular portion that is inserted into the vehicle body side tube and has an opening on the side of the tip end, and an annular lid portion that is connected to the outer periphery of the tubular portion and attached to the end of the vehicle body side tube, It consists of only one part, A cap that closes the open end of the tube on the vehicle body side; a ring-shaped cap that is inserted into the cylindrical portion and has a screw on the inner circumference groove a washer having an arm portion extending from the outer periphery of the nut portion and projecting out of the cylindrical portion through an opening and supporting an upper end of the suspension spring; a shaft portion having a screw groove formed on its outer periphery to be screwed into the nut portion; a flange portion provided at the rear end of the shaft portion; and an operating shaft portion extending from the opposite shaft portion side of the flange portion and having an operating portion at its tip, the adjuster being inserted into the cylindrical portion of the cap from the shaft portion side and rotatable in the circumferential direction relative to the cap, the operating portion projecting upward from the cylindrical portion; and the operating shaft portion, and the cylindrical portionand a stopper member that is attached to the inner periphery of the cap and abuts against the anti-shaft side of the flange portion to prevent the adjuster from coming off the cap.

[0018] In a front fork configured in this manner, the cap is made up of only one part instead of two parts, and there is no screw fastening part to screw the two parts together, so the position of the opening through which the arm of the washer is inserted can be positioned higher than in conventional front forks.

[0019] In this way, by positioning the opening in the cap upward, the support position of the upper end of the suspension spring supported by the arm portion of the washer can be shifted upward compared to conventional front forks, thereby shortening the overall length of the cap and increasing the storage length in the space within the front fork where the suspension spring is installed. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a vertical sectional view of a front fork in an embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged vertical cross-sectional view of an upper end of a front fork in the embodiment of the present invention. [Diagram 3] FIG. 3 is an enlarged vertical sectional view of an upper end of a front fork in a first modified example of the embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged vertical sectional view of an upper end of a front fork in a second modified example of the embodiment of the present invention. [Diagram 5] FIG. 5 is an enlarged vertical sectional view of an upper end of a front fork in a third modified example of the embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged vertical cross-sectional view of the upper end of a conventional front fork. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The present invention will be described below based on the embodiment shown in the drawings. As shown in Figures 1 and 2, a front fork 1 of the present invention is configured to include a fork body 2 including a tube member 3 in which a vehicle body side tube 3a and an axle side tube 3b are slidably fitted together and a suspension spring 4 that biases the tube member 3 in an extension direction, a cap 5 including a cylindrical portion 5a and a lid portion 5b that closes an open end 3a1 of the vehicle body side tube 3a, a washer 6 inserted into the cylindrical portion 5a, an adjuster 7 inserted into the cylindrical portion 5a and screwed onto the washer 6, and a stopper member 8 that prevents the adjuster 7 from coming off the cap 5.

[0022] Each part will be described below. As shown in FIG. 1, the fork body 2 includes a tube member 3 and a suspension spring 4, and a damper cartridge 10 that expands and contracts with the expansion and contraction of the tube member 3 to exert a damping force. The tube member 3 includes a vehicle body side tube 3a arranged on the upper side and connected to the vehicle body of a saddle riding vehicle (not shown), and an axle side tube 3b that has a smaller diameter than the vehicle body side tube 3a and is inserted into the vehicle body side tube 3a arranged on the lower side. The tube member 3 expands and contracts when the vehicle body side tube 3a and the axle side tube 3b move relatively in the axial direction. The upper end of the vehicle body side tube 3a is closed by a cap 5, and the lower end of the axle side tube 3b is closed by a bottom cap 11 that grips the axle of the front wheel of the saddle riding vehicle (not shown). Annular bearings 12 and 13 are provided between the vehicle body side tube 3a and the axle side tube 3b, allowing the vehicle body side tube 3a and the axle side tube 3b to move smoothly in the axial direction. Furthermore, an annular seal member 14 that slides against the outer periphery of the axle side tube 3b is provided on the inner periphery of the lower end of the vehicle body side tube 3a, and the internal space of the tube member 3 is sealed.

[0023] The damper cartridge 10 expands and contracts in accordance with the expansion and contraction of the tube member 3 to exert a damping force. The damper cartridge 10 includes a cylinder 10a fixed to a bottom cap 11 that closes the lower end opening of the axle-side tube 3b, a piston 10b slidably inserted into the cylinder 10a to divide the cylinder 10a into an expansion-side chamber R1 filled with liquid and a compression-side chamber R2, and a piston rod 10c connected to the piston 10b, inserted axially movably into the cylinder 10a, and connected to the cap 5 that closes the upper end opening of the vehicle-body-side tube 3a. The annular gap formed between the damper cartridge 10 and the tube member 3 is used as a reservoir R filled with liquid and gas, and the reservoir R communicates with the compression-side chamber R2 through a hole (not shown) provided in the cylinder 10a. Therefore, the volume of the liquid corresponding to the volume displaced within the cylinder 10a by the piston rod 10c moving in and out of the cylinder 10a during extension and contraction is exchanged between the inside of the cylinder 10a and the reservoir R, thereby compensating for the volume. Note that the liquid may be hydraulic oil or any liquid capable of exerting a damping force.

[0024] The piston 10b is annular and includes an expansion-side port 10b1 and a compression-side port 10b2 that communicate between the expansion-side chamber R1 and the compression-side chamber R2. An annular expansion-side leaf valve 10d that opens and closes the expansion-side port 10b1 is stacked at the lower end of the piston 10b in FIG. 1, and an annular compression-side leaf valve 10e that opens and closes the compression-side port 10b2 is stacked at the upper end of the piston 10b in FIG. 1. The piston 10b, the expansion-side leaf valve 10d, and the compression-side leaf valve 10e are all mounted on the outer periphery of a piston connecting member 10f that is connected to the lower end of the piston rod 10c in FIG. 1. The inner periphery of the expansion-side leaf valve 10d and the compression-side leaf valve 10e are fixed to the piston rod 10c, and when the outer periphery of the expansion-side leaf valve 10d and the compression-side leaf valve 10e are bent and separated from the piston 10b, they open the corresponding expansion-side port 10b1 and the compression-side port 10b2.

[0025] The piston rod 10c is cylindrical, and the upper end in FIG. 1 is connected to the cap 5 by screw fastening. The piston connecting member 10f connected to the lower end in FIG. 1 is cylindrical, and the piston 10b, the expansion-side leaf valve 10d, and the contraction-side leaf valve 10e are attached to the outer periphery. In addition, a bypass path B is formed through the inner periphery to communicate the expansion-side chamber R1 and the contraction-side chamber R2 by bypassing the expansion-side port 10b1 and the contraction-side port 10b2. A needle valve 10g is inserted inside the piston connecting member 10f so as to be movable in the axial direction. When the needle valve 10g moves in the axial direction inside the piston connecting member 10f, it increases or decreases the flow path area of ​​the bypass path B.

[0026] A cylindrical rod guide 10h, into which the piston rod 10c is slidably inserted, is attached to the inner periphery of the upper end of the cylinder 10a. In addition to guiding the axial movement of the piston rod 10c, the rod guide 10h also functions as a spring bearing that supports the lower end of the suspension spring 4, and as an oil lock case that prevents further contraction of the damper cartridge 10 and fork body 2 by the entry of an oil lock piece 10i provided on the outer periphery midway along the piston rod 10c.

[0027] Furthermore, an adjustment rod 15 is inserted into the piston rod 10c so as to be freely movable in the axial direction. The lower end of the adjustment rod 15 contacts the upper end of a needle valve 10g as shown in Fig. 1, and moving the adjustment rod 15 up and down also moves the needle valve 10g up and down, thereby adjusting the flow path area in the bypass path B. Note that the valve provided in the bypass path B is not limited to the needle valve 10g, and a variable damping valve that is displaced by the adjustment rod 15 in the bypass path B to vary the flow path area or the valve opening pressure can be used.

[0028] In the front fork 1 configured as above, when the fork body 2 extends, the damper cartridge 10 also extends, and the expansion-side chamber R1 is compressed by the piston 10b. When the extension speed of the fork body 2 is low and the pressure in the expansion-side chamber R1 is not enough to open the expansion-side leaf valve 10d, the liquid in the expansion-side chamber R1 moves to the compression-side chamber R2 through the bypass path B while the needle valve 10g is open. Since the needle valve 10g provides resistance to the flow of this liquid, a difference in pressure occurs between the expansion-side chamber R1 and the compression-side chamber R2, and the front fork 1 exerts a damping force that suppresses the expansion operation. When the extension speed of the fork body 2 becomes high and the expansion-side leaf valve 10d opens due to the action of the pressure in the expansion-side chamber R1, and the needle valve 10g is open, the liquid in the expansion-side chamber R1 moves to the compression-side chamber R2 through not only the bypass path B but also the expansion-side port 10b1. The needle valve 10g and the expansion-side leaf valve 10d provide resistance to this flow of fluid, which creates a difference in pressure between the expansion-side chamber R1 and the compression-side chamber R2, causing the front fork 1 to exert a damping force that suppresses the expansion action.

[0029] Here, since the valve opening of the needle valve 10g can be changed by moving the adjustment rod 15 in the axial direction, the damping force characteristics on the extension side of the front fork 1 (the damping force characteristics relative to the extension / retraction speed) can be adjusted.

[0030] When the fork body 2 contracts, the damper cartridge 10 also contracts, and the compression side chamber R2 is compressed by the piston 10b. When the contraction speed of the fork body 2 is low and the pressure in the compression side chamber R2 does not reach the valve opening pressure of the compression side leaf valve 10e, the liquid in the compression side chamber R2 moves to the expansion side chamber R1 through the bypass path B when the needle valve 10g is open. Since the needle valve 10g provides resistance to the flow of this liquid, a difference in pressure occurs between the compression side chamber R2 and the expansion side chamber R1, and the front fork 1 exerts a damping force that suppresses the contraction operation. When the contraction speed of the fork body 2 becomes high and the pressure in the compression side chamber R2 reaches the valve opening pressure of the compression side leaf valve 10e, the liquid in the compression side chamber R2 moves to the expansion side chamber R1 through not only the bypass path B but also the compression side port 10b2 when the needle valve 10g is open. Since the needle valve 10g and the compression-side leaf valve 10e provide resistance to this flow of fluid, a difference in pressure occurs between the compression-side chamber R2 and the expansion-side chamber R1, and the front fork 1 exerts a damping force that suppresses the contraction operation.

[0031] Also, when the front fork 1 is being compressed, the flow passage area of ​​the bypass passage B can be increased or decreased by adjusting the displacement of the needle valve 10g with the adjustment rod 15, thereby adjusting the damping force on the compression side of the front fork 1.

[0032] Next, a detailed description will be given of the cap 5, the washer 6, the adjuster 7, and the stopper member 8 attached to the cap 5. As shown in Fig. 2, the cap 5 has a cylindrical portion 5a which is inserted into the vehicle body side tube 3a and has an opening on the side of the tip side, and an annular lid portion 5b which is connected to the outer periphery of the cylindrical portion 5a and is attached to the end of the vehicle body side tube 3a.

[0033] The cylindrical portion 5a is a cylindrical portion with a bottom, and includes a small diameter portion 5a2 at the lower end, the inner diameter of which is smaller than that of the intermediate portion 5a1, and a large diameter portion 5a3 at the upper end, the inner diameter of which is larger than that of the intermediate portion 5a1. A screw groove is formed on the inner periphery of the small diameter portion 5a2, and a screw groove provided on the outer periphery of the upper end of the piston rod 10c in the damper cartridge 10 is screwed into the screw groove on the outer periphery of the upper end of the piston rod 10c and abuts against the lower end of the cylindrical portion 5a. The small diameter portion 5a2 and the nut 18 are fastened to each other to prevent loosening, and the fastening between the cylindrical portion 5a and the piston rod 10c is made strong.

[0034] The large diameter portion 5a3 has a hexagonal gripping portion 5a4 on the outer periphery of the upper end to enable gripping with a tool, and has an annular groove 5a5 on the inner periphery along the circumferential direction. Furthermore, the intermediate portion 5a1 of the cylindrical portion 5a is provided with a pair of rectangular openings 5a6 facing each other with a phase difference of 180 degrees.

[0035] The lid portion 5b protrudes from the side near the upper end of the cylindrical portion 5a toward the outer periphery in a flange shape, and has a screw portion 5b1 on the outer periphery. The lid portion 5b is connected to the vehicle body side tube 3a by screwing the screw portion 5b1 on the outer periphery into the screw portion 3a2 formed on the inner periphery of the open end 3a1 at the upper end of the vehicle body side tube 3a. A seal ring 17 that is in close contact with the inner periphery of the vehicle body side tube 3a is attached to the outer periphery of the lid portion 5b above the screw portion 5b1, thereby sealing the gap between the cap 5 and the vehicle body side tube 3a.

[0036] The washer 6 includes an annular nut portion 6a having a screw groove 6a1 on its inner circumference, and a pair of arms 6b extending from the outer circumference of the nut portion 6a and protruding out of the tubular portion 5a through an opening 5a6 in the tubular portion 5a. The washer 6 is vertically movable relative to the cap 5 within a range in which the arms 6b can move vertically within the opening 5a6 in the tubular portion 5a. The arms 6b of the washer 6 are slidably inserted into the opening 5a6 of the tubular portion 5a, and the washer 6 can move vertically within the tubular portion 5a, but is restricted from rotating in the circumferential direction around the nut portion 6a.

[0037] A cylindrical spacer 19 that fits onto the upper end of the suspension spring 4 is disposed on the outer periphery of the cylindrical portion 5a, and a spacer 20 is stacked on the upper end of the spacer 19 so as to be rotatable relative to the spacer 19. The arm portion 6b of the washer 6 abuts against the upper end of the spacer 20, and supports the upper end of the suspension spring 4 via the spacer 19 and the spacer 20. The suspension spring 4 is interposed in a compressed state between the rod guide 10h of the damper cartridge 10 and the washer 6.

[0038] The adjuster 7 is cylindrical overall and has a lower shaft portion 7a, a flange portion 7b provided on the outer periphery of the upper end (FIG. 2) which is the rear end of the shaft portion 7a, and an operating shaft portion 7c provided above the flange portion 7b, and is inserted into the cylindrical portion 5a of the cap 5 so as to be rotatable in the circumferential direction.

[0039] The shaft portion 7a has a screw groove 7a1 formed on its outer periphery to be screwed into the nut portion 6a of the washer 6. The flange portion 7b is provided from the upper end of the shaft portion 7a in FIG. 2 toward the outer periphery, and has an annular groove 7b1 on its outer periphery along the circumferential direction in which a seal ring 21 is housed. An end face 7b2 on the upper side in FIG. 2, which is the side opposite the shaft portion of the flange portion 7b, is a smooth perpendicular surface perpendicular to the axis of the adjuster 7. When the adjuster 7 is inserted into the appropriate position within the cylindrical portion 5a, the seal ring 21 comes into sliding contact with the inner circumferential surface above the opening 5a6 of the middle portion 5a1 of the cylindrical portion 5a, to seal between the adjuster 7 and the cylindrical portion 5a.

[0040] 2, which is the opposite end of the flange portion 7b, and has an operating portion 7c1 at its tip that can be gripped with a tool. When the adjuster 7 is inserted into the tubular portion 5a at an appropriate position, the operating portion 7c1 protrudes from the tubular portion 5a and is exposed to the outside of the front fork.

[0041] The adjuster 7 configured in this manner is inserted into the cylindrical portion 5a of the cap 5 from the shaft portion 7a side, and can rotate in the circumferential direction relative to the cap 5. Therefore, a user can use a tool to grasp the operating portion 7c1 and easily rotate the adjuster 7. The outer peripheral shape of the operating portion 7c1 is hexagonal, but it may be any shape other than hexagonal that is suitable for gripping with a tool.

[0042] The adjuster 7 has a screw groove 7d on its inner circumference. An operator 22, which abuts against the upper end of the adjustment rod 15 in FIG. 2, is rotatably inserted into the inner circumference of the adjuster 7. The operator 22 has a screw portion 22a on the outer circumference of the lower end in FIG. 2 that screws into the screw groove 7d. When the operator 22 is rotated by operating a tool inserted into a groove 22b provided in the head, the operator 22 moves in the vertical direction, which is the axial direction, relative to the adjuster 7. By rotating the operator 22 relative to the adjuster 7 in this way, the opening of the needle valve 10g can be adjusted via the adjustment rod 15, and the damping force generated by the damper cartridge 10 can be adjusted. The gap between the operator 22 and the adjuster 7 is sealed by a seal ring 23 attached to the outer circumference of the operator 22.

[0043] Next, the stopper member 8 is attached to the inner periphery of the large diameter portion 5a3 of the cylindrical portion 5a of the cap 5, and abuts against the end face 7b2 on the anti-shaft side of the flange portion 7b of the adjuster 7 to prevent the adjuster 7 from coming off the cap 5. In this manner, the stopper member 8 is attached to the inner periphery of the upper opening end of the cylindrical portion 5a of the cap 5.

[0044] In detail, the stopper member 8 includes a C-shaped ring 8a which is inserted into annular groove 5a5 provided on the inner circumference of the large diameter portion 5a3 of the tubular portion 5a, and a ring-shaped stopper 8b which is inserted between the tubular portion 5a and the operating shaft portion 7c and whose upward movement relative to the tubular portion 5a is restricted by the ring 8a and which abuts against the end face 7b2 on the anti-shaft side of the flange portion 7b.

[0045] The outer diameter of ring 8a is set to be greater than or equal to the diameter at the bottom of annular groove 5a5 of tubular portion 5a, and when the outer diameter is reduced, it can be inserted into tubular portion 5a. After being reduced in diameter, when it is inserted into annular groove 5a5, the restoring force tends to expand its outer diameter, causing it to become fixed in annular groove 5a5.

[0046] The stopper 8b is an annular part having a rectangular cross section, and can be inserted into the annular gap between the large diameter portion 5a3 of the cylindrical portion 5a and the operating shaft portion 7c of the adjuster 7, and is in sliding contact with both the large diameter portion 5a3 and the operating shaft portion 7c. The stopper 8b also has an annular recess 8b1 that accommodates the ring 8a on its outer periphery. Furthermore, the axial length of the stopper 8b is shorter than the axial length of the large diameter portion 5a3. In the front fork 1 of this embodiment, the annular recess 8b1 includes a first groove portion 8b11 whose inner diameter is smaller than the inner diameter of the ring 8a and whose depth is equal to or greater than the wire diameter of the ring 8a, and a second groove portion 8b12 adjacent to the lower side of the first groove portion 8b11 and whose depth is less than the wire diameter of the ring 8a. Furthermore, the first groove portion 8b11 has an axial width equal to or greater than the wire diameter of the ring 8a, and can completely accommodate the ring 8a. The axial width of the second groove portion 8b12 is preferably set to a width equal to or greater than half the wire diameter of the ring 8a. If the axial width of the second groove portion 8b12 is set to a width equal to or greater than half the wire diameter of the ring 8a, the outermost circumference of the ring 8a can be supported by the bottom of the second groove portion 8b12 even if an external force that reduces the diameter of the ring 8a acts, and reduction in the diameter of the ring 8a can be effectively suppressed.

[0047] The stopper 8b is fitted in the annular groove 5a5 of the large diameter portion 5a3 of the cylindrical portion 5a, and is prevented from coming off from the cylindrical portion 5a by the ring 8a disposed in the second groove portion 8b12 of the annular recess 8b1.

[0048] The lower end surface of stopper 8b is a smooth perpendicular surface perpendicular to the axis of adjuster 7, and when it abuts against the end face 7b2 on the anti-axis side of flange portion 7b, it supports flange portion 7b while allowing adjuster 7 to rotate smoothly, thereby preventing adjuster 7 from coming off tubular portion 5a.

[0049] To attach the stopper member 8 to the cylindrical portion 5a of the cap 5, first, the washer 6 is inserted into the cylindrical portion 5a, and then the adjuster 7 is inserted into the cylindrical portion 5a so that the shaft portion 7a is screwed into the nut portion 6a of the washer 6. At this time, the operating element 22 is preliminarily assembled to the inner periphery of the adjuster 7, and is inserted into the cylindrical portion 5a together with the adjuster 7 when the adjuster 7 is inserted into the cylindrical portion 5a.

[0050] Then, the slit of the ring 8a is widened to expand its diameter, and the ring 8a is brought into opposition to the first groove portion 8b11 in the annular recess 8b1 of the stopper 8b, and then the diameter is reduced. Then, the ring 8a is completely housed in the first groove portion 8b11 of the stopper 8b.

[0051] The stopper member 8 in the above state is inserted into the annular gap between the cylindrical portion 5a of the cap 5 and the operating shaft portion 7c of the adjuster 7. When the ring 8a is inserted into the large diameter portion 5a3 of the cylindrical portion 5a together with the stopper 8b, the ring 8a is prevented from expanding in diameter by the inner periphery of the large diameter portion 5a3 until it faces the annular groove 5a5, and therefore the ring 8a is inserted into the large diameter portion 5a3 together with the stopper 8b in a reduced diameter state.

[0052] The stopper 8b is inserted into the large diameter portion 5a3, and the degree of insertion into the large diameter portion 5a3 of the stopper 8b progresses. When the ring 8a faces the annular groove 5a5, the ring 8a expands in diameter, enters the annular groove 5a5, and is fixed to the tubular portion 5a. When the ring 8a is inserted into the annular groove 5a5, the ring 8a abuts against the side surface of the first groove portion 8b11 on the upper side in FIG. 2, and the stopper 8b cannot be pushed further into the tubular portion 5a. Note that there are cases where the stopper 8b and the flange portion 7b abut against each other when the stopper member 8 is inserted into the annular gap between the tubular portion 5a and the adjuster 7. Since the adjuster 7 supports the upper end of the suspension spring 4 together with the washer 6, the suspension spring 4 compresses depending on the degree to which the stopper member 8 penetrates into the tubular portion 5a, so that even if the stopper 8b and the flange portion 7b abut, the stopper member 8 can be inserted into the tubular portion 5a together with the adjuster 7.

[0053] 2 of the first groove portion 8b11 and it becomes impossible to further push the stopper 8b into the cylindrical portion 5a, and then the pushing of the stopper 8b is stopped, the biasing force of the suspension spring 4 pushes the stopper 8b together with the adjuster 7 upward relative to the cylindrical portion 5a, and the ring 8a is inserted into the second groove portion 8b12 in the annular recess 8b1. Since the depth of the second groove portion 8b12 is less than the wire diameter of the ring 8a, when the ring 8a is inserted into the second groove portion 8b12, the inner circumference of the ring 8a comes into contact with the bottom of the second groove portion 8b12, restricting the reduction in diameter of the ring 8a, and the outer circumference of the ring 8a is maintained in a state of protruding radially beyond the outer circumference of the stopper 8b.

[0054] Therefore, when the ring 8a is inserted into the second groove portion 8b12, even if an external force is applied to the ring 8a in a direction that causes the ring 8a to contract in diameter, the ring 8a protrudes radially beyond the outer periphery of the stopper 8b and is maintained in a state inserted into the annular groove 5a5, preventing the ring 8a from falling off from the annular groove 5a5. Therefore, the stopper member 8 is prevented from falling off from the cylindrical portion 5a, and the adjuster 7 can be prevented from coming off.

[0055] When the ring 8a faces the annular groove 5a5, the ring 8a expands in diameter and makes a striking sound as it enters the annular groove 5a5, so that the assembly worker can recognize the completion of the fitting of the ring 8a in the annular groove 5a5 by the presence or absence of the striking sound when fitting the stopper member 8 to the cylindrical portion 5a. However, if the stopper 8b is inserted into the large diameter portion 5a3 until it cannot be pushed any further into the cylindrical portion 5a, the stopper 8b will enter beyond the position where the ring 8a faces the annular groove 5a5, so that the ring 8a can be prevented from being left out of the fitting into the annular groove 5a5.

[0056] When the ring 8a is inserted into the annular groove 5a5 and the second groove portion 8b12 of the stopper 8b, the height of the upper end surface of the stopper 8b in Fig. 2 and the upper end surface of the cylindrical portion 5a become exactly the same, and the upper end surface of the stopper 8b and the upper end surface of the cylindrical portion 5a become flush with each other. In this way, when the ring 8a is inserted into the annular groove 5a5 and the second groove portion 8b12, the upper end surface of the stopper 8b in Fig. 2 and the upper end surface of the cylindrical portion 5a are set to be flush with each other, and the assembly worker can determine whether the ring 8a is properly attached to the cylindrical portion 5a and the stopper 8b according to the state of the position of the upper end surface of the stopper 8b in Fig. 2 and the position of the upper end surface of the cylindrical portion 5a. Therefore, when the ring 8a is inserted into the annular groove 5a5 and the second groove portion 8b12, and the upper end surface of the stopper 8b in Figure 2 is set to be flush with the upper end surface of the tubular portion 5a, the presence or absence of a defective assembly of the stopper member 8 can be determined from the outside by checking the height between the stopper 8b and the tubular portion 5a.

[0057] When the stopper member 8 is attached to the tubular portion 5a, the adjuster 7 is positioned in the axial direction by the stopper member 8 at a position where the lower end surface of the stopper 8b abuts against the end surface 7b2 of the flange portion 7b of the adjuster 7 on the counter-shaft side. In this way, the position at which the adjuster 7 is positioned relative to the tubular portion 5a of the cap 5 by the stopper member 8 becomes the appropriate position of the adjuster 7 relative to the tubular portion 5a. Since the lower end surface of the stopper 8b and the end surface 7b2 of the counter-shaft side of the flange portion 7b of the adjuster 7 form an orthogonal plane that is orthogonal to the axis of the adjuster 7, the adjuster 7 can rotate smoothly in the circumferential direction at the positioned position, and the stopper member 8 prevents the adjuster 7 from coming off the tubular portion 5a.

[0058] The first groove portion 8b11 in the annular recess 8b1 of the stopper 8b in the stopper member 8 may be formed up to the upper end of the stopper 8b, in which case an annular pocket is formed between the inner circumference of the large diameter portion 5a3 of the cylindrical portion 5a and the outer circumference of the stopper 8b. In this case, it is preferable to provide an annular lid that covers the pocket and prevents dust and the like from accumulating in the pocket.

[0059] Next, the suspension spring 4 is interposed between the rod guide 10h of the damper cartridge 10 and the washer 6, and constantly biases the vehicle body side tube 3a and the axle side tube 3b in a direction separating them in the axial direction. Therefore, the tube member 3 is biased in a direction in which it expands due to the elastic force of the suspension spring 4.

[0060] When a user of the front fork 1 grips the operating portion 7c1 of the adjuster 7 with a tool and rotates it, the washer 6 screwed onto the outer periphery of the shaft portion 7a is displaced in the vertical direction, which is the axial direction, in the manner of a feed screw, because its rotation is restricted by the cylindrical portion 5a. In this way, when the washer 6 moves in the vertical direction relative to the cylindrical portion 5a of the cap 5 by rotating the adjuster 7, the support position of the upper end of the suspension spring 4 also changes with the displacement of the washer 6, so that the vehicle height of a saddle-riding vehicle to which the front fork 1 is applied can be adjusted.

[0061] As described above, the front fork 1 comprises the fork body 2 having the tube member 3 in which the vehicle body side tube 3a and the axle side tube 3b are slidably fitted together, the suspension spring 4 which biases the tube member 3 in the extension direction, the cap 5 which has a tubular portion 5a which is inserted into the vehicle body side tube 3a and has an opening 5a6 on the side of the tip end thereof, and an annular lid portion 5b which is connected to the outer periphery of the tubular portion 5a and is attached to the end of the vehicle body side tube 3a, thereby closing the open end of the vehicle body side tube 3a, and the annular lid portion 5b which is inserted into the tubular portion 5a and has a screw threaded on the inner periphery thereof. groovean adjuster 7 having a nut portion 6a having a threaded hole 6a1, an arm portion 6b extending from the outer periphery of the nut portion 6a and protruding outside the cylindrical portion 5a through an opening 5a6 and supporting the upper end of the suspension spring 4, a shaft portion 7a having a screw groove 7a1 formed on its outer periphery to be screwed into the nut portion 6a, a flange portion 7b provided at the rear end of the shaft portion 7a, and an operating shaft portion 7c extending from the anti-shaft side of the flange portion 7b and having an operating portion 7c1 at its tip, the adjuster 7 being inserted into the cylindrical portion 5a of the cap 5 from the shaft side and rotatable in the circumferential direction relative to the cap 5, with the operating portion 7c1 protruding upward from the cylindrical portion 5a, and a stopper member 8 attached to the inner periphery of the cylindrical portion 5a of the cap 5 and abutting against the anti-shaft side of the flange portion 7b to prevent the adjuster 7 from coming off the cap 5.

[0062] In the front fork 1 configured in this manner, the cap 5 is composed of only one part instead of two parts, and a stopper member 8 that prevents the adjuster 7 from coming off the cap 5 is attached to the inner periphery of the tubular portion 5a of the cap 5 and abuts against the anti-shaft side of the flange portion 7b. Therefore, the cap 5 is not composed of two parts that are screwed together, but is composed of one part and there is no screw fastening portion that screw fastens the two parts together, so the position of the opening 5a6 through which the arm portion 6b of the washer 6 is inserted can be positioned higher compared to conventional front forks.

[0063] In this way, by locating the position of the opening 5a6 in the cap 5 upward, the support position on the upper side of the suspension spring 4 supported by the arm portion 6b of the washer 6 can be shifted upward compared to the conventional front fork, so that the overall length of the cap 5 can be shortened accordingly, and the axial length (storage length) of the space in which the suspension spring 4 is installed in the front fork 1 can be increased. Since the storage length of the suspension spring 4 can be increased in this way, the degree of freedom in setting design parameters of the suspension spring 4, such as the wire diameter, natural length, pitch, etc., of the suspension spring 4, is improved. As described above, according to the front fork 1 of this embodiment, the overall length of the cap 5 can be shortened, and the degree of freedom in design of the suspension spring 4 can be improved.

[0064] Furthermore, according to the front fork 1 configured in this manner, the overall length of the cap 5 can be shortened to reduce the weight of the cap 5, and therefore the weight of the front fork 1 can be reduced.

[0065] In the front fork 1 of this embodiment, the stopper member 8 is attached to the inner circumference of the open end of the tubular portion 5a. With the front fork 1 configured in this manner, the adjuster 7 can be disposed above the tubular portion 5a, so that the overall length of the cap 5 can be further shortened and the design freedom of the suspension spring 4 can be further improved.

[0066] In the front fork 1 of this embodiment, the stopper member 8 includes a ring 8a inserted into the annular groove 5a5 provided on the inner circumference of the tubular portion 5a, and a stopper 8b that is annular and inserted between the tubular portion 5a and the operating shaft portion 7c, and the ring 8a restricts the upward movement of the stopper member 8 relative to the tubular portion 5a, and abuts against the counter-shaft side of the flange portion 7b. According to the front fork 1 configured in this manner, the end face 7b2 on the counter-shaft side of the flange portion 7b of the adjuster 7 and the end face on the tube body side of the stopper 8b are in surface contact with each other, so that the adjuster 7 can be rotated smoothly when it is rotated. Note that the stopper member 8 may be composed of only the C-shaped ring 8a, as long as it is attached to the inner circumference of the tubular portion 5a and prevents the adjuster 7 from coming off the tubular portion 5a. However, the resistance when rotating the adjuster 7 will be larger than when the stopper 8b is in surface contact with the flange portion 7b.

[0067] In addition, in the front fork 1 of this embodiment, the stopper 8b has an annular recess 8b1 that accommodates the ring 8a on its outer periphery, and the annular recess 8b1 has a first groove portion 8b11 whose inner diameter is smaller than the inner diameter of the ring 8a and has a depth equal to or greater than the wire diameter of the ring 8a, and a second groove portion 8b12 that is adjacent to and below the first groove portion 8b11 and has a depth less than the wire diameter of the ring 8a.

[0068] According to the front fork 1 configured in this manner, when the stopper member 8 is inserted into the annular gap between the cylindrical portion 5a and the operating shaft portion 7c, the ring 8a can be accommodated in the first groove portion 8b11 so as not to interfere with the insertion of the stopper 8b into the annular gap. Furthermore, according to the front fork 1 configured in this manner, after the ring 8a is attached to the annular groove 5a5, the ring 8a is inserted into the second groove portion 8b12 to restrain the ring 8a so that the outer diameter of the ring 8a does not become equal to or smaller than the inner diameter of the large diameter portion 5a3, thereby preventing the ring 8a from falling off the annular groove 5a5.

[0069] Furthermore, in the front fork 1 of this embodiment, the inner periphery of the stopper 8b is in sliding contact with the outer periphery of the operating shaft portion 7c, and the outer periphery of the stopper 8b is in sliding contact with the inner periphery of the tubular portion 5a. With the front fork 1 configured in this manner, the annular gap between the tubular portion 5a and the adjuster 7 can be filled with the stopper 8b, improving the appearance around the adjuster 7 and preventing the intrusion of dust and the like into the annular gap.

[0070] In the front fork 1 of this embodiment, the upper end surface of the stopper 8b and the upper end surface of the tubular portion 5a are flush with each other when the ring 8a is inserted into the annular groove 5a5. With the front fork 1 configured in this manner, after the stopper member 8 is attached to the cap 5, it can be confirmed whether the position of the upper end surface of the stopper 8b and the position of the upper end surface of the tubular portion 5a are flush with each other, and whether or not the stopper member 8 is improperly assembled can be determined from the outside.

[0071] In the above, when the ring 8a is inserted into the annular groove 5a5, the upper end surface of the stopper 8b is flush with the upper end surface of the tubular portion 5a. However, as shown in FIG. 3, the upper end of the stopper 8b may protrude upward from the tubular portion 5a. In this case, a tapered chamfered portion 8b2 is provided on the outer periphery of the upper end of the stopper 8b, and when the ring 8a is inserted into the annular groove 5a5, the position of the lower end of the chamfered portion 8b2 is at the same height as the position of the upper end surface of the tubular portion 5a. Therefore, according to the front fork 1 configured in this manner, after the stopper member 8 is attached to the cap 5, it is possible to check whether the position of the lower end surface of the chamfered portion 8b2 of the stopper 8b is the same as the position of the upper end surface of the tubular portion 5a, and to judge from the outside whether the stopper member 8 is assembled incorrectly. Therefore, in order to be able to judge from the outside whether the stopper member 8 is assembled incorrectly, a position recognition means for visually checking the axial position of the stopper 8b with respect to the tubular portion 5a may be provided. In the example shown in FIG. 3, the position recognition means is configured by a chamfered portion 8b2 provided on the outer periphery of the upper end of the stopper 8b, but if the upper end of the stopper 8b protrudes upward from the tubular portion 5a, a mark may be provided on the outer periphery of the stopper 8b by engraving, cutting, or painting. Even in the case of a mark, if the position of the mark on the stopper 8b and the position of the upper end of the tubular portion 5a are at the same height, it can be confirmed that the ring 8a is inserted into the annular groove 5a5. Therefore, if a position recognition means is provided that can visually confirm the axial position of the stopper 8b relative to the tubular portion 5a, the presence or absence of an assembly defect of the stopper member 8 can be determined by checking the height of the stopper 8b and the tubular portion 5a from the outside.

[0072] Instead of using the ring 8a, the stopper member 8 may be fixed to the tubular portion 5a by press-fitting the stopper member 81, which is an annular part with a rectangular cross section, into the inner circumference of the large diameter portion 5a3 of the tubular portion 5a, as shown in Fig. 4, or the stopper member 82 may be an annular part with a rectangular cross section, which is provided with a threaded portion on the outer circumference, and which is also provided with a threaded portion on the inner circumference of the large diameter portion 5a3 of the tubular portion 5a, so that the stopper member 82 is screwed to the tubular portion 5a, as shown in Fig. 5. When the stopper member 82 is screwed to the tubular portion 5a, it is advisable to provide a part that prevents the stopper member 82 from rotating relative to the tubular portion 5a.

[0073] Furthermore, in the front fork 1 of this embodiment, the cap 5 has a large diameter portion 5a3 at the upper end of the tubular portion 5a, which has a large inner diameter, but the inner diameter from the middle portion upward may be made the same and the large diameter portion 5a3 may be omitted. However, if the large diameter portion 5a3 is provided, the seal ring 21 attached to the outer periphery of the flange portion 7b of the adjuster 7 does not come into contact with the large diameter portion 5a3 when the adjuster 7 is inserted into the tubular portion 5a, making it easier to insert the adjuster 7 into the tubular portion 5a.

[0074] 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]

[0075] DESCRIPTION OF SYMBOLS 1 front fork, 2 fork body, 3 tube member, 3a body side tube, 3b axle side tube, 4 suspension spring, 5 cap, 5a cylinder portion, 5a5 annular groove, 5a6 opening, 5b cover portion, 6 washer, 6a nut portion, 6b arm portion, 7 adjuster, 7a shaft portion, 7a1 screw groove, 7b flange portion, 7c operating shaft portion, 7c1 operating portion, 8, 81, 82 stopper member, 8a ring, 8b stopper, 8b1 annular recess, 8b11 first groove portion, 8b12 second groove portion

Claims

1. A front fork, a fork body including a tube member in which a vehicle body side tube and an axle side tube are slidably fitted together, and a suspension spring that biases the tube member in an extension direction; a cap that is formed of only one component and that includes a tubular portion that is inserted into the vehicle body side tube and has an opening on a side portion on the tip side, and an annular lid portion that is connected to the outer periphery of the tubular portion and is attached to the end portion of the vehicle body side tube, and that closes the open end of the vehicle body side tube; a washer including: a nut portion having an annular shape and inserted into the cylindrical portion and having a screw groove on an inner circumference; and an arm portion extending from an outer circumference of the nut portion, protruding outside the cylindrical portion through the opening, and supporting an upper end of the suspension spring; an adjuster having a shaft portion having a screw groove formed on an outer periphery thereof to be screwed into the nut portion, a flange portion provided at a rear end of the shaft portion, and an operating shaft portion extending from a side opposite to the shaft portion of the flange portion and having an operating portion at a tip thereof, the adjuster being inserted into the cylindrical portion of the cap from the shaft portion side and rotatable in a circumferential direction relative to the cap, the operating portion protruding upward from the cylindrical portion; a stopper member that is inserted between the cylindrical portion of the cap and the operating shaft portion and is attached to an inner periphery of the cylindrical portion so as to abut against the anti-shaft portion side of the flange portion to prevent the adjuster from coming off the cap. A front fork characterized by:

2. The stopper member is attached to the inner periphery of the open end of the cylindrical portion.

2. The front fork according to claim 1 .

3. The stopper member is a ring inserted into an annular groove provided on an inner periphery of the cylindrical portion; a stopper that is annular and is inserted between the cylindrical portion and the operating shaft portion, the stopper restricting the upward movement of the operating shaft portion relative to the cylindrical portion by the ring and abutting against the opposite shaft portion of the flange portion; 2. The front fork according to claim 1 .

4. The stopper has an annular recess on an outer periphery thereof for receiving the ring, The annular recess has an inner diameter smaller than the inner diameter of the ring and a depth equal to or greater than the wire diameter of the ring; a second groove portion adjacent to and below the first groove portion and having a depth less than the wire diameter of the ring; 4. The front fork according to claim 3.

5. The inner periphery of the stopper is in sliding contact with the outer periphery of the operating shaft portion, The outer periphery of the stopper is in sliding contact with the inner periphery of the cylindrical portion.

5. The front fork according to claim 3 or 4.

6. A position recognition function that visually recognizes an axial position of the stopper relative to the cylindrical portion. Equipped with the means 5. The front fork according to claim 3 or 4.

7. When the ring is inserted into the annular groove, the upper end surface of the stopper and the upper end surface of the cylindrical portion are flush with each other.

6. The front fork according to claim 5.

8. The stopper is pushed up by the biasing force of the suspension spring, so that the upper end surface of the stopper and the cylindrical portion become flush with each other.

8. The front fork according to claim 7.

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