Front fork

Abstract

The present invention is provided with: a tube member (T) having a vehicle-body-side tube (1) and an axle-side tube (2) that is movable in the axial direction with respect to the vehicle-body-side tube (1); a suspension spring (S) housed in the tube member (T) and biasing the tube member (T) in the extension direction; a cam device (3) that is housed in the vehicle body-side tube (1), supports one end of the suspension spring (S), and has an annular cam member (31) that axially moves in stages by rotation in the circumferential direction; a shaft (4) which is inserted into the vehicle-body-side tube (1) so as to be rotatable in the circumferential direction, the lower end of which is connected to the cam member (31), and the upper end of which protrudes outside the vehicle-body-side tube (1); and a manually operable dial (5) provided on the upper end side of the shaft (4) and disposed outside the vehicle body side tube (1).

Description

TECHNICAL FIELD

[0001] The present application relates to a front fork. BACKGROUND

[0002] In the past, a front fork has been provided with: an extension member having a body side tube linked to a vehicle body in a vehicle and a axle side tube axially movable with respect to the body side tube linked to an axle of a front wheel; and a suspension spring housed in the extension member and applying a force in a direction separating the body side tube and the axle side tube, for suspending the front wheel of the vehicle.

[0003] In such a front fork, as disclosed in JP 2016-200257 A, a rod member is provided which is axially movably inserted into the extension member and supports one end of the suspension spring via a spring seat mounted to a lower end, and a bottomed cylindrical operation portion is screwed with a thread groove provided to an outer periphery of an upper end of the rod member, and by performing a rotational operation on the operation portion, the rod member is axially moved with the principle of feeding a thread to adjust an initial load of the suspension spring. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0004] Patent Document 1: JP 2016-200257 A SUMMARY PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] In the past, the operation portion of the front fork is screwed with the thread groove provided to the outer periphery of the upper end of the rod member, and thus a rotational operation on the operation portion using a tool is required. However, if the vehicle in which the front fork is mounted is a vehicle provided with a housing covering the entire upper end of the front fork, such as a scooter, it can not be possible to secure a space for operating the operation portion using a tool.

[0006] In addition, in the past, the rod member is axially moved with the principle of feeding a thread by screwing the operation portion with the thread groove provided to the outer periphery of the upper end of the rod member, and thus in order to set the initial load of the suspension spring to a desired size, the operator needs to know in advance how much to rotate the operation portion. However, as described above, in a state where the upper end of the front fork is covered by a housing or the like and the operation portion cannot be visually recognized, it is difficult to know in advance how much to rotate the operation portion, and it is difficult to adjust the initial load of the suspension spring to a desired size.

[0007] To address this, an object of the present application is to provide a front fork which can minimize a space required around an operation portion, and can easily adjust an initial load of a suspension spring to a desired size even in a state where the operation portion cannot be visually recognized. TECHNICAL MEANS FOR SOLVING THE PROBLEMS

[0008] To solve the foregoing problems, the front fork of the present application is characterized by comprising: an extension member having a vehicle body side tube and an axle side tube; a suspension spring housed in the extension member and applying a force in a direction separating the vehicle body side tube and the axle side tube; a cam device housed in the vehicle body side tube and supporting one end of the suspension spring, and having a ring-shaped cam member that moves axially in stages by rotation in a circumferential direction; a shaft rotatably inserted into the vehicle body side tube in the circumferential direction, with one end side coupled to the cam member; and a manually operable operation portion provided at the other end side of the shaft and disposed outside the vehicle body side tube. According to this configuration, since the manually operable operation portion that adjusts the initial load of the suspension spring is disposed at the upper portion of the front fork, the space around the operation portion required for operating the operation portion is only required to be large enough to allow the hand to be inserted. Further, the cam member is moved axially in stages by rotating the operation portion, and the initial load of the suspension spring can be adjusted in stages, so that the amount of adjustment of the initial load of the suspension spring can be grasped in steps, and when the step of the initial load of the suspension spring is switched, a clicking sensation is transmitted to the worker who rotates the operation portion through the shaft and the operation portion, and the worker can perceive that the step of the initial load of the suspension spring has been switched without looking at the operation portion. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a side view showing a part of a suspension straddle vehicle to which the front fork of the present embodiment is applied. Figure 2 is a front side cross-sectional view of the front fork of the present embodiment. Figure 3 is an enlarged partial cross-sectional view showing the upper portion of the front fork of the present embodiment. Figure 4 is an exploded perspective view of the adjuster and the cover in the front fork of the present embodiment. Figure 5 (A) is an expanded view of the cam device of the present embodiment and shows a first stage of the cam device, Figure 5 (B) is an expanded view of the cam device of the present embodiment and shows a second stage of the cam device, Figure 5 (C) is an expanded view of the cam device of the present embodiment and shows a third stage of the cam device. EMBODIMENT

[0010] Hereinafter, the front fork F of the present embodiment will be described with reference to the drawings. The same symbols are annotated in some of the drawings to indicate the same parts. In addition, unless otherwise specified, the up and down when the front fork F is mounted to a vehicle will be simply referred to as "up" and "down".

[0011] As Figure 1As shown in the drawing, the front fork F of the present embodiment is a suspension device of a suspension straddle vehicle V suspending a front wheel W. The suspension straddle vehicle refers to all vehicles of a type that are ridden in a posture straddling a saddle, including motorcycles, scooters, bicycles, and the like. The front fork F of the present invention can be mounted on any suspension straddle vehicle.

[0012] As shown in the drawing, the front fork F of the present embodiment is a suspension device of a suspension straddle vehicle V suspending a front wheel W. The suspension straddle vehicle refers to all vehicles of a type that are ridden in a posture straddling a saddle, including motorcycles, scooters, bicycles, and the like. The front fork F of the present invention can be mounted on any suspension straddle vehicle. Figure 2 As shown in the drawing, the front fork F of the present embodiment is provided with: a pipe member T as an extension member, having a vehicle body side pipe 1 and a vehicle axle side pipe 2 that is axially movable with respect to the vehicle body side pipe 1; a suspension spring S housed in the pipe member T and applying a force in a direction separating the vehicle body side pipe 1 and the vehicle axle side pipe 2; and an adjuster A provided at the vehicle body side (upper end) of the vehicle body side pipe 1 to support one end (upper end) of the suspension spring S, and adjustable to the initial load of the suspension spring S.

[0013] Next, the detailed structure of the front fork F of the present embodiment will be described. As shown in the drawing, the front fork F of the present embodiment is a suspension device of a suspension straddle vehicle V suspending a front wheel W. The suspension straddle vehicle refers to all vehicles of a type that are ridden in a posture straddling a saddle, including motorcycles, scooters, bicycles, and the like. The front fork F of the present invention can be mounted on any suspension straddle vehicle. Figure 2 As shown in the drawing, the front fork F of the present embodiment is a suspension device of a suspension straddle vehicle V suspending a front wheel W. The suspension straddle vehicle refers to all vehicles of a type that are ridden in a posture straddling a saddle, including motorcycles, scooters, bicycles, and the like. The front fork F of the present invention can be mounted on any suspension straddle vehicle. Figure 1 As shown in the drawing, the front fork F of the present embodiment is a suspension device of a suspension straddle vehicle V suspending a front wheel W. The suspension straddle vehicle refers to all vehicles of a type that are ridden in a posture straddling a saddle, including motorcycles, scooters, bicycles, and the like. The front fork F of the present invention can be mounted on any suspension straddle vehicle.

[0014] Thus, the front fork F configures the vehicle axle side pipe 2 toward the front wheel (wheel) W side, and configures the vehicle body side pipe 1 toward the vehicle body B side, thereby being interposed between the vehicle body B and the axle of the front wheel W. Moreover, when the suspension straddle vehicle V is running on a bumpy road or the like and the front wheel W is oscillated up and down, the vehicle body side pipe 1 is advanced and retracted in the vehicle axle side pipe 2, and the front fork F is extended and contracted. Furthermore, in the present embodiment, the description of the vehicle axle side bracket BW is omitted. Figure 2

[0015] In addition, the upper end opening of the vehicle body side pipe 1 is plugged by the following cover 6 and the adjuster A. On the other hand, the vehicle axle side pipe 2 is a bottomed cylindrical shape, and the lower end opening of the vehicle axle side pipe 2 is plugged by the bottom portion 2a thereof. Furthermore, the overlapping portion between the vehicle axle side pipe 2 and the vehicle body side pipe 1 is plugged by an oil seal 11 and a dust seal 12. Thus, the inside of the pipe member T becomes a closed space, and a liquid and a gas are enclosed in the pipe member T thereof.

[0016] Furthermore, in the bottom portion 2a of the vehicle axle side pipe 2, a cylinder 10 is coupled by a bolt 13. The cylinder 10 has a cylindrical portion 10a, and a ring-shaped valve housing portion 10b protruding radially outward from the upper end of the cylindrical portion 10a, and is inserted into the vehicle body side pipe 1 in a manner along the axial direction from the lower end of the vehicle axle side pipe 2.

[0017] ​The pipe member T is divided into a cylindrical liquid chamber L formed on the outer peripheral side of the cylinder 10 and a reservoir chamber R formed on the inner peripheral side of the cylinder 10. The liquid chamber L is filled with a liquid such as hydraulic oil. On the other hand, the reservoir chamber R stores the same liquid as the liquid chamber L and is sealed with a gas such as air above the liquid surface. Further, the liquid surface of the reservoir chamber R is always located on the upper side than the upper end of the cylinder 10 when the fork F is extended and contracted.

[0018] Further, a piston 15 that divides the liquid chamber L into an upper elongation-side chamber LI and a lower compression-side chamber L2 is provided at the lower end portion of the vehicle body side pipe 1. Specifically, the piston 15 has a housing 16 that is a top-hat-shaped cylinder having a hole (not shown) allowing the cylinder 10 to be inserted through the top (not shown), a second compression-side check valve 17 that is disposed on the inner peripheral side of the housing 16 and allows only the liquid to pass through the elongation-side chamber LI from the compression-side chamber L2, and a cylindrical lock housing 18 that abuts against the lower end of the housing 16 and supports the second compression-side check valve 17.

[0019] The vehicle body side pipe 1 has a small-diameter cylindrical portion la and a large-diameter cylindrical portion lb that is continuous with the lower end of the small-diameter cylindrical portion la and has a larger inner diameter than the small-diameter cylindrical portion la, and a step portion lc is formed at the boundary between the small-diameter cylindrical portion la and the large-diameter cylindrical portion lb. Further, in a state where the upper end of the piston 15 (the upper end of the housing 16) abuts against the step portion lc, the piston 15 is attached to the lower end portion of the vehicle body side pipe 1 by crimping the lower end of the vehicle body side pipe 1. Note that the piston 15 can be fixed to the vehicle body side pipe 1 by a method other than crimping.

[0020] Further, the piston 15 of the present embodiment is an example, and the piston 15 can be configured in any manner as long as the liquid chamber L is divided into the elongation-side chamber LI and the compression-side chamber L2.

[0021] Further, an extension spring 19 is stacked on the upper side of the piston 15. Further, the extension spring 19 is compressed between the piston 15 and the valve housing portion 10b when the fork F is most extended, and the impact at the time of the most extension is thereby mitigated. Further, the extension spring 19 is compressed between the piston 15 and the valve housing portion 10b when the fork F is most contracted, and the impact at the time of the most contraction is thereby mitigated. Figure 2 The extension spring 19 shown is a coil spring, but can be a spring other than a coil spring. Further, instead of the extension spring 19, a cushion rubber or the like can be provided and the impact at the time of the most extension of the fork F can be mitigated by the cushion rubber or the like.

[0022] Further, a cylindrical lock piece 20 is erected at the bottom 2a of the axle side pipe 2. Further, the lock piece 20 is inserted into the lock housing 18 when the fork F is most contracted. In this way, the pressure in the lock housing 18 rises and the hydraulic lock is activated, and the impact at the time of the most contraction of the fork F is thereby mitigated.

[0023] Further, as shown in FIG. 6, the lock piece 20 is provided with a hole 20a that is formed in the center of the lock piece 20 and allows the lock housing 18 to be inserted through the hole 20a. Further, the hole 20a is formed so as to be coaxial with the lock housing 18. Figure 2As shown, in the upper portion of the cylinder 10, throttle holes 10c, 10d that communicate between the inside and outside of the cylinder 10 are provided side by side in the up-down direction. Each of the throttle holes 10c, 10d is provided at a position opposite the elongation-side chamber LI in a state in which no load is applied to the fork F.

[0024] In addition, in the lower portion of the cylinder 10, a communication hole 10e that communicates between the compression-side chamber L2 and the liquid reservoir chamber R is provided. The communication hole 10e is formed to a size that allows liquid to pass therethrough without resistance, and thus liquid is able to flow freely between the compression-side chamber L2 and the liquid reservoir chamber R via the communication hole 10e.

[0025] In addition, on the outer periphery of the valve housing portion 10b, a first compression-side check valve 14 that is in sliding contact with the inner periphery of the vehicle body-side pipe 1 and that allows only liquid to pass from the liquid reservoir chamber R to the elongation-side chamber LI is installed.

[0026] According to the fork F configured in this way, when the fork F is elongated as the vehicle body-side pipe 1 is withdrawn from the axle-side pipe 2, the first compression-side check valve 14 closes and the piston 15 moves upward within the liquid chamber L, simultaneously reducing the elongation-side chamber LI and enlarging the compression-side chamber L2.

[0027] When the fork F is elongated, the first compression-side check valve 14 closes, the liquid of the elongation-side chamber LI moves to the liquid reservoir chamber R via the throttle holes 10c, 10d, and the enlarged volume of liquid of the compression-side chamber L2 is supplied from the liquid reservoir chamber R to the compression-side chamber L2 via the communication hole 10e. Thus, when the fork F is elongated, resistance is applied to the flow of liquid from the elongation-side chamber LI toward the liquid reservoir chamber R by the throttle holes 10c, 10d. Thus, when the fork F is elongated, the pressure of the elongation-side chamber LI rises, and an elongation-side damping force that hinders the elongation action of the fork F is generated.

[0028] In addition, when the fork F is further elongated, the second compression-side check valve 17 of the piston 15 moves upward of each of the throttle holes 10c, 10d, and the communication of each of the throttle holes 10c, 10d with the elongation-side chamber LI is sequentially interrupted from the lower throttle hole 10d.

[0029] Furthermore, when the fork F is most elongated and the second compression-side check valve 17 of the piston 15 moves to the upper side of the upper throttle hole 10c, the communication of the elongation-side chamber LI with the liquid reservoir chamber R is completely interrupted, and thus the elongation-side chamber LI is sealed and the hydraulic lock takes effect. Thus, in this embodiment, the impact at the time when the fork F is most elongated is mitigated by the elastic force of the aforementioned extension spring 19 and the aforementioned hydraulic lock. Furthermore, when the impact at the time when the fork F is most elongated can be sufficiently mitigated by the aforementioned hydraulic lock, the extension spring 19 can be omitted.

[0030] In addition, as described above, the throttle holes 10c, 10d of the present embodiment are arranged in parallel on the upper portion of the cylinder 10, and are sequentially cut off from the lower throttle hole 10d as the fork F extends. Therefore, near the end of stroke of the extension operation of the fork F, the damping force on the extension side gradually increases. Therefore, when the fork F extends, the damping force on the extension side can be suppressed from increasing sharply to deteriorate the ride comfort. Further, the number of the throttle holes 10c, 10d is not limited to two, and can be one or more than three.

[0031] On the contrary, when the fork F contracts as the vehicle body side pipe 1 intrudes into the axle side pipe 2, the vehicle body side pipe 1 intrudes into the liquid chamber L between the axle side pipe 2 and the cylinder 10, and the piston 15 moves downward in the liquid chamber L to enlarge the extension side chamber Ll while reducing the compression side chamber L2.

[0032] When the fork F contracts, the liquid of the compression side chamber L2 moves to the liquid storage chamber R through the communication hole 10e. Further, when the fork F contracts, the first compression side check valve 14 opens, the liquid of the liquid storage chamber R is supplied to the extension side chamber Ll, and the second compression side check valve 17 opens to supply the liquid of the compression side chamber L2 to the extension side chamber Ll.

[0033] When the fork F contracts, the liquid of the compression side chamber L2 moves to the liquid storage chamber R through the communication hole 10e almost without resistance, and therefore the damping force on the compression side that hinders the contraction operation of the fork F is not generated or becomes extremely small. However, the damping force on the compression side can be generated, for example, by providing a damping valve between the compression side chamber L2 and the liquid storage chamber R.

[0034] Further, in the present embodiment, when the fork F contracts, the first compression side check valve 14 and the second compression side check valve 17 open to supply the liquid from both the liquid storage chamber R and the compression side chamber L2 to the enlarged extension side chamber Ll, and therefore the liquid deficiency of the extension side chamber Ll can be surely prevented to make the extension side chamber Ll into a negative pressure. However, in the case where the liquid is not deficient in the extension side chamber Ll when the liquid is supplied from only either the liquid storage chamber R or the compression side chamber L2, either of the first compression side check valve 14 and the second compression side check valve 17 can be omitted. Further, the structure inside the fork F described above is an example, and is not limited to the above structure.

[0035] Returning to Figure 2 As shown, a suspension spring S is laminated on the upper side of the valve housing portion 10b, and the upper end of the suspension spring S is supported by an adjuster A provided on the upper end of the vehicle body side pipe 1. Therefore, when the vehicle body side pipe 1 intrudes into the axle side pipe 2 to contract the fork F, the compression amount of the suspension spring S increases, and the elastic force of the suspension spring S that resists the compression increases. Thus, the suspension spring S exerts the elastic force corresponding to the compression amount thereof, and elastically supports the vehicle body B by applying the force to the fork F in the extension direction.

[0036] As shown in Figure 3 , the adjuster A of the present embodiment is provided with: a ring-shaped cam follower member 30 fixedly housed in the vehicle body side pipe 1; a cam member 31 rotatably and axially movably housed in the vehicle body side pipe 1 and interposed between the upper end of the suspension spring S and the cam follower member 30; a shaft 4 rotatably inserted into the vehicle body side pipe 1 and having a lower end (one end) coupled to the cam member 31 and an upper end (the other end) protruding outside the vehicle body side pipe 1 through the cam follower member 30; and a dial 5 as an operation portion provided on the upper end side of the shaft 4 and disposed outside the vehicle body side pipe 1.

[0037] In detail, the adjuster A is provided at the upper end of the vehicle body side pipe 1 via a cylindrical cover 6 that closes the upper end opening of the vehicle body side pipe 1. The cover 6 is made of metal, as shown in Figure 3 , Figure 4 , has a cylindrical cover body 60 inserted with one side in sliding contact with the inner periphery of the vehicle body side pipe 1 and a ring-shaped flange portion 61 provided at the upper end of the cover body 60 and having an outer diameter substantially the same as the outer diameter of the vehicle body side pipe 1 and a lower surface in abutment with the upper end of the vehicle body side pipe 1. In addition, the gap between the outer periphery of the cover body 60 and the inner periphery of the vehicle body side pipe 1 is sealed by a ring-shaped outer peripheral seal 62 mounted to a ring-shaped groove (not shown) formed in the outer periphery of the upper end of the cover body 60. Further, the cover 6 is fixed to the inner periphery of the vehicle body side pipe 1 by screwing. However, the method of fixing the cover 6 to the vehicle body side pipe 1 is not limited to screwing, and for example, the cover 6 can be fixed to the vehicle body side pipe 1 by crimping the upper end outer periphery of the vehicle body side pipe 1 in a state where the cover body 60 is inserted into the inner periphery of the vehicle body side pipe 1. Furthermore, in Figure 4 , the threaded portion provided on the outer periphery of the cover body 60 is omitted.

[0038] In addition, as shown in Figure 3 , Figure 4 , the shaft 4 is provided with: a protruding shaft portion 40 protruding outside the vehicle body side pipe 1 in a state of being inserted into the vehicle body side pipe 1; a first mounting shaft portion 41 connected to the lower end of the protruding shaft portion 40 and having a larger diameter than the protruding shaft portion 40; and a second mounting shaft portion 42 connected to the lower end of the first mounting shaft portion 41.

[0039] Further, the cover 6 is clamped by split rings 43 and 44 respectively mounted to the outer peripheries of the upper end and the lower end of the first mounting shaft portion 41 of the shaft 4. Thus, the shaft 4 is held so as to be relatively rotatable while restricting axial movement of the cover 6. Therefore, as shown in Figure 2 , Figure 3 , when the cover 6 is fixed to the vehicle body side pipe 1, the shaft 4 is in a state of being rotatably inserted in the circumferential direction with respect to the vehicle body side pipe 1.

[0040] Further, an annular inner periphery seal 64 is attached to an annular groove (not shown) formed in the inner periphery of the cover body 60, and the inner periphery seal 64 is in sliding contact with the outer periphery of the shaft 4 inserted into the cover 6, thereby sealing the gap between the cover 6 and the shaft 4.

[0041] Further, a dial 5 is provided as a manually operable operation portion on the protruding shaft portion 40 of the shaft 4, and the dial 5 functions as a handle when the shaft 4 is rotated in the circumferential direction.

[0042] Specifically, as shown in Figure 3 , Figure 4 the dial 5 has a top cylinder-shaped fitting portion 50, an annular flange portion 51 protruding radially from the lower end of the fitting portion 50, and a plurality of ridge portions 52 provided at intervals in the circumferential direction of the fitting portion 50 and standing up from the upper end of the flange portion 51. The interval between the adjacent ridge portions 52, 52 is set to a size that can accommodate a finger, and thus when the dial 5 is operated by an operator, the operator can insert a finger between the ridge portions 52, 52, and the operator can easily hold the dial 5.

[0043] Further, although not shown, the protruding shaft portion 40 has a shape in which two portions opposed in the radial direction of a cylinder are cut in the axial direction, and on the other hand, the inner periphery shape of the fitting portion 50 is a shape that matches the outer periphery shape of the protruding shaft portion 40. Therefore, when the fitting portion 50 of the dial 5 is fitted to the upper end of the protruding shaft portion 40, the dial 5 is stopped from rotating relative to the protruding shaft portion 40. Further, the outer periphery shape of the protruding shaft portion 40 and the inner periphery shape of the fitting portion 50 are not necessarily a perfect circle, and for example, can be a D shape or a quadrangular shape.

[0044] Further, by fitting the fitting portion 50 of the dial 5 to the protruding shaft portion 40, in a state in which a hole provided at the top (not shown) of the fitting portion 50 is opposed to a threaded hole (not shown) opened at the upper portion of the protruding shaft portion 40, a bolt 53 is screwed into the threaded hole, and thus the dial 5 is fixed in a state in which relative rotation with respect to the upper end of the shaft 4 is prevented.

[0045] However, the method of fixing the dial 5 to the shaft 4 is an example, and is not limited to the above-described method, and for example, the dial 5 can be fixed to the shaft 4 by adhesion or welding. Further, the shape of the dial 5 described above is an example, and the shape of the dial 5 is not limited to the above-described configuration.

[0046] Further, at the lower end of the cover body 60, an annular cam follower member 30 that is annular and allows the insertion and circumferential direction rotation of the shaft 4 is non-rotatably linked, and the cam follower member 30 is fixedly housed in the vehicle body side pipe 1.

[0047] Specifically, as shown in Figure 4As shown, at the lower end of the cover body 60, there is provided a fitting portion 63 formed by axially cutting away the outer circumference of two radially opposing portions of the cover body 60 to form opposite sides. Furthermore, at the upper end of the cam follower 30, there is provided a pair of plate-shaped anti-rotation pieces 33 that can be respectively fitted into the two fitting portions 63. By fitting each anti-rotation piece 33 into each fitting portion 63, the cam follower 30 and the cover body 60 are connected so as to be non-rotatable relative to each other.

[0048] Furthermore, an annular cam member 31 is coupled to the lower end of the shaft 4, i.e., the outer periphery of the second mounting shaft portion 42, so as to be non-rotatable relative to the second mounting shaft portion 42 and axially movable along the second mounting shaft portion 42. Furthermore, the upper end of the suspension spring S abuts against the lower end of the cam member 31, and the cam member 31 supports the upper end of the suspension spring S.

[0049] Specifically, if Figure 4 As shown, the second mounting shaft portion 42 of the shaft 4 is formed by cutting away two radially opposing portions of the cylinder in the axial direction. Furthermore, the inner circumference of the cam member 31 conforms to the outer circumference of the second mounting shaft portion 42. Furthermore, by inserting the second mounting shaft portion 42 through the inner circumference of the cam member 31 and attaching the cam member 31 to the outer circumference of the second mounting shaft portion 42, the cam member 31 is connected to the shaft 4 in a manner that restricts relative rotation thereof but allows axial movement thereof.

[0050] However, the inner circumferential shape of the cam member 31 and the outer circumferential shape of the second mounting shaft portion 42 may not be a perfect circle, and may be, for example, a D shape or a square. Furthermore, the method for preventing the cam member 31 from rotating relative to the second mounting shaft portion 42 is not limited to the above method.

[0051] The cam follower 30 and the cam member 31 are each formed of a synthetic resin, and constitute the cam device 3 capable of changing the axial position of the upper end of the suspension spring S in steps.

[0052] Specifically, if Figure 5 As shown, two protrusion groups 31A and 31B are continuously provided along the circumferential direction at the upper end of the cam member 31. The protrusion groups 31A and 31B have a plurality of protrusions 31a, 31b, and 31c with different axial heights in the circumferential direction. However, the protrusion groups 31A and 31B may be arranged spaced apart in the circumferential direction.

[0053] If numbered sequentially from the highest protrusion in each protrusion group 31A, 31B, each protrusion group 31A, 31B includes a first protrusion 31a, a second protrusion 31b having a lower axial height than the first protrusion 31a, and a third protrusion 31c having a lower axial height than the second protrusion 31b. The protrusions 31a, 31b, and 31c are arranged in this order clockwise as viewed from the dial 5. In other words, in this embodiment, the plurality of protrusions 31a, 31b, and 31c are arranged so that their axial height gradually decreases in a clockwise direction as viewed from the dial 5.

[0054] On the other hand, Figure 5 As shown, two recess groups 30A and 30B are continuously provided along the circumferential direction at the lower end of the cam follower 30. These recess groups 30A and 30B include a plurality of recesses 30a, 30b, and 30c having different axial heights in the circumferential direction. However, the recess groups 30A and 30B may also be spaced apart in the circumferential direction.

[0055] Numbering the recesses in each recess group 30A or 30B starting from the lowest recess, each recess group 30A or 30B includes a first recess 30a, a second recess 30b having a higher axial height than the first recess 30a, and a third recess 30c having a higher axial height than the second recess 30b. The recesses 30a, 30b, and 30c are arranged in this order clockwise as viewed from the dial 5. That is, in this embodiment, the recesses 30a, 30b, and 30c are arranged so that their axial height increases in a stepwise manner as viewed from the dial 5.

[0056] Moreover, if Figure 5 As shown in Figure 1, the recesses 30a, 30b, and 30c provided at the lower end of the cam follower 30 engage with the protrusions 31a, 31b, and 31c provided at the upper end of the cam member 31. In other words, the recess groups 30A and 30B of the cam follower 30 and the protrusion groups 31A and 31B of the cam member 31 have conforming shapes. Furthermore, the number of protrusion groups 31A and 31B and recess groups 30A and 30B is not limited to two; it can be one or three or more.

[0057] Next, a detailed description will be given of a method for operating the adjuster A. In this embodiment, the adjuster A can adjust the initial load of the suspension spring S in three stages.

[0058] In the first stage of the cam device 3, the initial load of the suspension spring S is minimum, as shown in FIG. Figure 5(A) shown, the first protrusion 31a of the cam member 31 is engaged with the first recess 30a of the cam follower member 30, the second protrusion 31b of the cam member 31 is engaged with the second recess 30b of the cam follower member 30, and the third protrusion 31c of the cam member 31 is engaged with the third recess 30c of the cam follower member 30.

[0059] Here, the protrusion groups 31A, 31B and the recess groups 30A, 30B are respectively continuously arranged in the circumferential direction, so as to be Figure 5 (A) shown, the first protrusion 31a of the cam member 31 is engaged with the first recess 30a of the cam follower member 30, the second protrusion 31b of the cam member 31 is engaged with the second recess 30b of the cam follower member 30, and the third protrusion 31c of the cam member 31 is engaged with the third recess 30c of the cam follower member 30.

[0060] Furthermore, if the operator rotates the dial 5 in the clockwise direction to rotate the cam member 31 in the clockwise direction via the shaft 4 before the first protrusion 31a and the second protrusion 31b of the cam member 31 are respectively engaged with the second recess 30b and the third recess 30c of the cam follower member 30, as Figure 5 (B) shown, the cam device 3 is switched from the first stage to the second stage.

[0061] At this time, in the state where the cam member 31 is pressed against the cam follower member 30 by the suspension spring S, the first protrusion 31a and the second protrusion 31b are respectively engaged with the second recess 30b and the third recess 30c, so the click feeling due to the vibration at the time of engagement is transmitted to the operator through the shaft 4 and the dial 5. Therefore, the operator can perceive that the cam device 3 is switched from the first stage to the second stage by the click feeling.

[0062] Thus, when the cam device 3 becomes the second stage, the cam member 31 moves downward (the suspension spring S side) along the shaft 4 by the difference in the axial height of the first recess 30a and the second recess 30b of the cam follower member 30, so the suspension spring S is compressed, and the initial load of the suspension spring S is greater than that of the first stage of the cam device 3.

[0063] Next, if the operator rotates the dial 5 in the clockwise direction to rotate the cam member 31 in the clockwise direction via the shaft 4 before the first protrusion 31a of the cam member 31 is engaged with the third recess 30c of the cam follower member 30, as Figure 5 (C) shown, the cam device 3 is switched from the second stage to the third stage.

[0064] At this time, while the cam member 31 is pressed against the cam follower 30 by the suspension spring S, the first protrusion 31a and the third recess 30c engage with each other. Therefore, a click sensation caused by the vibration during engagement is transmitted to the operator via the shaft 4 and the dial 5. Therefore, the operator can sense that the cam device 3 has switched from the second stage to the third stage through the click sensation.

[0065] When the cam device 3 enters the third stage, the cam member 31 moves downward along the shaft 4 by the difference in axial height between the second recess 30b and the third recess 30c of the cam follower 30, thereby further compressing the suspension spring S and maximizing the initial load of the suspension spring S.

[0066] Here, if Figure 3 、 Figure 4 As shown, a stopper ring 45 serving as a stopper is provided on the outer periphery of the lower side of the second mounting shaft portion 42 of the shaft 4, which abuts against the suspension spring S side end of the cam component 31 to limit the movement of the cam component 31 downward (to the suspension spring S side) until the cam component 31 is spaced apart from the cam follower component 30 to the maximum extent possible when the first protrusion 31a with the highest axial height is engaged with the third recess 30c with the highest axial height.

[0067] The state in which the cam component 31 is maximally spaced apart from the cam follower component 30 mentioned here means that when the cam component 31 is further rotated clockwise from the state in which the first protrusion 31a is engaged with the third recess 30c, the first protrusion 31a moves along the side of the third recess 30c and the first protrusion 31a presses over the front end portion 30c1 of the side of the third recess 30c.

[0068] In this way, if the cam component 31 is spaced apart from the cam follower component 30 to the maximum extent in the state in which the first protrusion 31a is engaged with the third recess 30c, the block ring 45 is used to abut against the suspension spring S side end of the cam component 31 to limit the cam component 31 from moving downward (to the suspension spring S side), the engaging object of the first protrusion 31a with the highest axial height in the cam component 31 is pressed from the third recess 30c with the highest axial height in the cam follower 30 over the front end portion 30c1 of the third recess 30c and switched to the first recess 30a with the lowest axial height, thereby preventing a large impact from occurring.

[0069] Furthermore, when the initial load of the suspension spring S is reduced, the operating dial 5 is rotated counterclockwise to rotate the shaft 4 counterclockwise, thereby rotating the cam member 31 counterclockwise.

[0070] Thus, in the adjuster A of the present embodiment, by rotating the dial 5 in the circumferential direction, the cam member 31 is rotated in the circumferential direction and axially moved in stages, and it is possible to adjust the magnitude of the initial load of the suspension spring S in stages.

[0071] Further, in the present embodiment, the number of stages of the initial load of the suspension spring S that can be adjusted is set to three stages, but is not particularly limited, and can be set to any number of stages as long as it is two or more. In this case, the number of the protrusions 31a, 31b, 31c provided to the cam member 31 and the recesses 30a, 30b, 30c provided to the cam follower member 30 can be appropriately increased or decreased according to the number of stages of the initial load of the suspension spring S that can be adjusted.

[0072] Further, in the present embodiment, the dial 5, which is a manually operable operation portion that adjusts the initial load of the suspension spring S, is disposed at the upper portion of the front fork F. Thus, the space around the dial 5 required for operating the dial 5 is sufficient as long as it is a size in which a hand can be inserted, and thus it is possible to minimize the space required around the dial 5.

[0073] Thus, for example as shown in Figure 1 , the front fork F of the present embodiment is mounted on a scooter that has a housing C that covers the entire upper end of the front fork F, and even if the space around the dial 5 is narrow, as long as there is a space in which a hand can be inserted between the housing C and the dial 5, the worker can adjust the initial load of the suspension spring S by inserting a hand into the gap between the housing C and the dial 5 and rotating and operating the dial 5.

[0074] Further, in the front fork F of the present embodiment, by rotating and operating the dial 5, it is possible to axially move the cam member 31 in stages and adjust the magnitude of the initial load of the suspension spring S in stages, and thus it is possible to grasp the adjustment amount of the initial load of the suspension spring S in stages.

[0075] Further, when switching the number of stages of the initial load of the suspension spring S, a click feeling is transmitted to the worker who rotates and operates the dial 5 by the shaft 4 and the dial 5, and thus the worker can perceive that the number of stages of the initial load of the suspension spring S has been switched without looking at the dial 5.

[0076] Thus, the front fork F, as shown in Figure 1 , even in a state in which the upper end of the front fork F is covered by the housing C and the worker cannot visually recognize the dial 5, it is easy to grasp the adjustment amount of the initial load of the suspension spring S, and thus it is possible to easily adjust the initial load of the suspension spring S to the desired magnitude.

[0077] Further, in the present embodiment, the operation section provided at the upper end of the front fork F is a dial 5, but the operation section is not particularly limited as long as it can be manually operated by a worker, and for example, a rod that protrudes in the radial direction can be provided. If such a rod is provided, since the distance from the center of rotation of the shaft 4 to the force point becomes large, the shaft 4 can be rotated with a smaller force.

[0078] Further, in the present embodiment, both the cam member 31 and the cam follower member 30 that constitute the cam device 3 are formed of synthetic resin, but either one or both of the cam member 31 and the cam follower member 30 can be formed of a material other than synthetic resin, such as metal. However, in the case where the cam member 31 and the cam follower member 30 are formed of metal, when the cam member 31 is rotated in the circumferential direction, the cam member 31 and the cam follower member 30 rub against each other to generate metal powder. In this case, since the cam device 3 is housed in the front fork F, the metal powder is mixed in the liquid housed in the front fork F, and can attack the oil seal 11 or the dust seal 12 that seals the gap between the vehicle body side tube 1 and the axle side tube 2.

[0079] In contrast, as shown in the present embodiment, if the cam member 31 and the cam follower member 30 are formed of synthetic resin, metal powder is not generated even if the cam member 31 and the cam follower member 30 rub against each other, and thus the seal member is not attacked.

[0080] Further, synthetic resin is lighter than metal, and thus if the cam member 31 and the cam follower member 30 are formed of synthetic resin, the front fork F can be made lightweight. Further, synthetic resin is easier to process than metal, and thus if the cam member 31 and the cam follower member 30 are formed of synthetic resin, it is easy to provide the protrusions 31a, 31b, 31c and the recesses 30a, 30b, 30c to the cam member 31 and the cam follower member 30, respectively.

[0081] Further, synthetic resin has a smaller coefficient of friction than metal, and thus if the cam member 31 and the cam follower member 30 are formed of synthetic resin, the force required for the step switching of the cam device 3 becomes small, and thus the operability of the dial 5 is improved.

[0082] Further, in the present embodiment, the cover 6 and the cam follower member 30 are separate bodies, and thus the cover 6 can be made of metal and the cam follower member 30 can be made of synthetic resin, that is, the cover 6 and the cam follower member 30 can be made of different materials. However, if the cam follower member 30 is made of metal, the cam follower member 30 can be integrally provided at the lower end of the cover 6.

[0083] Furthermore, in this embodiment, the cam member 31 is non-rotatably coupled to the lower end of the shaft 4, i.e., the outer circumference of the second mounting shaft portion 42, but axially movable along the second mounting shaft portion 42. However, the cam member 31 may alternatively be fixedly coupled to the lower end of the shaft 4 so as to allow the shaft 4 to move axially relative to the cover 6. However, if the cam member 31 is fixedly coupled to the lower end of the shaft 4, the shaft 4 will also move axially along with the cam member 31 as the cam member 31 rotates circumferentially and moves axially. This could potentially cause problems such as the upper end of the shaft 4 interfering with the vehicle body B.

[0084] In contrast, in this embodiment, the cam member 31 is coupled to the outer periphery of the second mounting shaft portion 42 of the shaft 4 so as to be non-rotatable relative to the outer periphery and axially movable along the second mounting shaft portion 42. Therefore, when the cam member 31 rotates circumferentially and moves axially, the cam member 31 moves on the second mounting shaft portion 42. Therefore, the shaft 4 does not move axially, and there is no risk of the upper end of the shaft 4 interfering with the vehicle body B.

[0085] Next, the method for assembling the adjuster A and cover 6 to the upper end of the vehicle body side tube 1 will be described in detail. First, a snap ring 44 is attached to the outer periphery of the lower end of the first mounting shaft portion 41 of the shaft 4. The first mounting shaft portion 41 is then inserted from the lower side of the cover 6 toward the inner side of the cover 6, and the cover 6 is attached to the outer periphery of the first mounting shaft portion 41. Subsequently, a snap ring 43 is attached to the outer periphery of the upper end of the first mounting shaft portion 41 of the shaft 4. This retains the cover 6 rotatably relative to the shaft 4 while restricting axial movement.

[0086] Here, if Figure 3 、 Figure 4 As shown, the first mounting shaft portion 41 of the shaft 4 has a large-diameter portion 41a that is continuous with the upper end of the second mounting shaft portion 42, and a small-diameter portion 41b that is continuous with the upper end of the large-diameter portion 41a and has an outer diameter smaller than that of the large-diameter portion. Furthermore, when the cover 6 is mounted on the outer periphery of the first mounting shaft portion 41, the inner peripheral seal 64 mounted on the inner periphery of the cover body 60 is in sliding contact with the outer periphery of the large-diameter portion 41a of the first mounting shaft portion 41.

[0087] Therefore, in this embodiment, as described above, when the first mounting shaft portion 41 is inserted from the lower side of the cover 6 to the inner side of the cover 6, the inner peripheral seal 64 installed on the inner periphery of the cover body 60 does not contact the inner periphery of the small diameter portion 41b of the first mounting shaft portion 41, or even if the inner peripheral seal 64 contacts the inner periphery of the small diameter portion 41b of the first mounting shaft portion 41, the friction is small.

[0088] Therefore, when the cover 6 is mounted on the first mounting shaft portion 41 , the distance over which the inner seal 64 rubs against the outer periphery of the first mounting shaft portion 41 can be shortened, thereby suppressing degradation of the inner seal 64 and facilitating assembly of the cover 6 to the first mounting shaft portion 41 .

[0089] Next, the lower end of the shaft 4 is inserted from the upper side of the cam follower member 30 to the inner side of the cam follower member 30, the rotation-preventing piece 33 provided at the upper end of the cam follower member 30 is fitted to the fitting portion 63 provided at the lower end of the cover body 60, and the cam follower member 30 and the lower end of the cover body 60 are non-rotatably connected.

[0090] Thereafter, the second mounting shaft portion 42 of the shaft 4 is inserted from the upper side of the cam member 31 to the inner side of the cam member 31, the stopper ring 45 is mounted to the outer periphery of the lower end of the second mounting shaft portion 42, and the cam member 31 is prevented from being detached from the shaft 4.

[0091] Finally, the dial 5 is fixed to the upper end of the shaft 4, that is, the protruding shaft portion 40, and the adjuster A having the shaft 4, the dial 5, the cam follower member 30, and the cam member 31, and the cover 6 are assembled, and thus the assembly is completed.

[0092] Further, if the adjuster A and the cover 6 are assembled in this manner, the cover 6 of the assembly is simply screwed to the upper end inner periphery of the vehicle body side pipe 1, and thus the adjuster A can be provided at the upper end of the vehicle body side pipe 1.

[0093] Further, the above-described method of assembling the adjuster A and the cover 6 at the upper end of the vehicle body side pipe 1 is an example, and is not limited to the above-described method.

[0094] As described above, the front fork F of the present embodiment includes the pipe member T as the extension member, the vehicle body side pipe 1 and the vehicle axle side pipe 2 which is axially movable with respect to the vehicle body side pipe 1, the suspension spring S which is housed in the pipe member T and which applies a force in a direction in which the vehicle body side pipe 1 and the vehicle axle side pipe 2 are separated, the cam device 3 which is housed in the vehicle body side pipe 1 and which supports one end of the suspension spring S, and which has the annular cam member 31 which is axially moved in stages by rotation in the circumferential direction, the shaft 4 which is rotatably inserted into the vehicle body side pipe 1 in the circumferential direction and which is connected to the cam member 31 at one end side, and the dial 5 as the manually operable operation portion which is provided at the other end side of the shaft 4 and which is disposed outside the vehicle body side pipe 1.

[0095] According to the above-described configuration, the dial 5 as the manually operable operation portion which adjusts the initial load of the suspension spring S is disposed at the upper portion of the front fork F. Therefore, the space around the dial 5 required for operating the dial 5 is sufficient as long as the size in which a hand can be put in, and thus the space required around the dial 5 can be minimized.

[0096] Therefore, for example, as Figure 1As shown, the front fork F of the present embodiment is mounted on a scooter provided with a housing C that covers the entire upper end of the front fork F, and even if the space around the dial 5 narrows, as long as there is a space between the housing C and the dial 5 into which a hand can be inserted, the worker can adjust the initial load of the suspension spring S by inserting a hand into the gap between the housing C and the dial 5 and rotating the dial 5.

[0097] In addition, in the front fork F of the present embodiment, by rotating the dial 5, the cam member 31 is axially moved in stages to adjust the size of the initial load of the suspension spring S in stages, and thus the amount of adjustment of the initial load of the suspension spring S can be grasped in steps.

[0098] Further, when the step of the initial load of the suspension spring S is switched, a click feeling is transmitted to the worker who rotates the dial 5 through the shaft 4 and the dial 5, and thus the worker can perceive that the step of the initial load of the suspension spring S has been switched without looking at the dial 5.

[0099] Therefore, according to the above configuration, the front fork F as shown, even in a state where the upper end of the front fork F is covered by the housing C and the worker cannot visually recognize the dial 5, the amount of adjustment of the initial load of the suspension spring S is easily grasped, and thus the initial load of the suspension spring S can be easily adjusted to the desired size. Figure 1

[0100] Further, in the present embodiment, the operation portion provided on the upper portion of the front fork F is the dial 5, but the operation portion is not particularly limited as long as it can be manually operated by the worker, and for example, a rod that protrudes in the radial direction can be provided. If such a rod is provided, since the distance from the rotation center of the shaft 4 to the force point becomes large, the shaft 4 can be rotated with a smaller force. However, if the operation portion is the dial 5, the size in the radial direction can be made compact compared to the case where the rod is provided, and thus the space required around the operation portion can be further reduced.

[0101] In addition, in the front fork F of the present embodiment, the cam device 3 has a ring-shaped cam follower member 30 housed in the vehicle body side tube 1, and a cam member 31 interposed between the cam follower member 30 and the suspension spring S, the cam member 31 has a plurality of protrusions 31a, 31b, 31c that differ in axial height in the circumferential direction, and the cam follower member 30 has a plurality of recesses 30a, 30b, 30c that differ in axial height in the circumferential direction and can be engaged with the protrusions 31a, 31b, 31c.

[0102] ​According to this configuration, in the cam device 3, the plurality of protrusions 31a, 31b, 31c and the plurality of recesses 30a, 30b, 30c are engaged at a plurality of positions, respectively, and thus the contact area of the cam member 31 and the cam follower member 30 becomes large. Therefore, the pressure acting on the cam member 31 and the cam follower member 30 can be reduced by the spring force of the suspension spring S.

[0103] In addition, in the front fork F of the present embodiment, the cam member 31 has a plurality of protrusion groups 31A, 31B having a plurality of protrusions 31a, 31b, 31c and arranged in the circumferential direction, the cam follower member 30 has a plurality of recess groups 30A, 30B having a plurality of recesses 30a, 30b, 30c and arranged at positions respectively facing the protrusion groups 31A, 31B in the axial direction, and among the plurality of protrusion groups 31A, 31B and the plurality of recess groups 30A, 30B, one protrusion group 31A and one recess group 30A and the other protrusion group 31B and the other recess group 30B are engaged with the same number of protrusions 31a, 31b, 31c and recesses 30a, 30b, 30c, respectively.

[0104] According to this configuration, according to the number of the protrusion groups 31A, 31B and the recess groups 30A, 30B, the number of the engagement of the protrusions 31a, 31b, 31c and the recesses 30a, 30b, 30c increases, and thus the contact area of the cam member 31 and the cam follower member 30 becomes larger. Therefore, the pressure acting on the cam member 31 and the cam follower member 30 can be further reduced by the spring force of the suspension spring S. However, the number of the protrusion groups 31A, 31B and the recess groups 30A, 30B is not particularly limited, and can be one.

[0105] Further, in the present embodiment, the cam device 3 is configured by the cam member 31 having a plurality of protrusions 31a, 31b, 31c having different axial heights at the upper end and the cam follower member 30 having a plurality of recesses 30a, 30b, 30c having different axial heights at the lower end, but the above-described configuration of the cam device 3 is an example, and the configuration of the cam device 3 is not limited as long as the cam member 31 can move the cam member 31 in the axial direction in stages when the cam member 31 rotates in the circumferential direction.

[0106] For example, instead of the plurality of protrusions 31a, 31b, 31c, only one protrusion that can be fitted into the recesses 30a, 30b, 30c can be provided at the upper end of the cam member 31, and the cam member 31 is rotated in the circumferential direction, and when the protrusion is fitted into any one of the plurality of recesses 30a, 30b, 30c provided at the cam follower member 30 at different axial heights, the cam member 31 is axially moved in stages according to the axial height of the recess. Alternatively, one protrusion can be provided at the lower end of the cam follower member 30, and a plurality of recesses at different axial heights in the circumferential direction can be provided at the upper end of the cam member 31, and when the protrusion of the cam follower member 30 is fitted into any one of the recesses of the cam member 31, the cam member 31 is axially moved in stages according to the axial height of the recess.

[0107] In addition, in the front fork F of the present embodiment, the cam device 3 is formed of synthetic resin. According to this configuration, when the cam member 31 is rotated in the circumferential direction, metal powder is not generated even if the cam member 31 rubs against the cam follower member 30. Therefore, metal powder mixed in the liquid contained in the front fork F does not attack the oil seal 11 or the dust seal 12 that seals the gap between the vehicle body side tube 1 and the axle side tube 2.

[0108] In addition, if both the cam member 31 and the cam follower member 30 of the cam device 3 are formed of synthetic resin, the front fork F can be made lighter compared to a case where one or both of the cam member 31 and the cam follower member 30 are formed of a material other than synthetic resin, such as metal.

[0109] In addition, synthetic resin has a smaller coefficient of friction compared to metal, and therefore if the cam member 31 and the cam follower member 30 are formed of synthetic resin, the force required for the cam device 3 to switch the number of stages is smaller, and therefore the operability of the dial 5 is improved.

[0110] In addition, synthetic resin is easier to process compared to metal, and therefore if both the cam member 31 and the cam follower member 30 are formed of synthetic resin, it is easy to provide the protrusions 31a, 31b, 31c and the recesses 30a, 30b, 30c at the cam member 31 and the cam follower member 30, respectively. However, one or both of the cam member 31 and the cam follower member 30 of the cam device 3 can be formed of a material other than synthetic resin, such as metal.

[0111] Further, in the front fork F of the present embodiment, the plurality of protrusions 31a, 31b, 31c provided to the cam member 31 are arranged so that the axial height is lowered in stages in the clockwise direction as viewed from the side of the dial 5 which is one direction in the circumferential direction, and the plurality of recesses 30a, 30b, 30c of the cam follower member 30 are arranged so that the axial height is raised in stages in the clockwise direction as viewed from the side of the dial 5 which is one direction in the circumferential direction, and a stopper ring 45 as a stopper is provided to the outer periphery of the shaft 4, which abuts against the suspension spring S side end of the cam member 31 to restrict the movement of the cam member 31 to the suspension spring S side, and the cam member 31 is maximally spaced apart from the cam follower member 30 in a state in which the first protrusion 31a having the highest axial height is engaged with the third recess 30c having the highest axial height.

[0112] According to this configuration, by the engagement target of the first protrusion 31a having the highest axial height in the cam member 31 being pressed over the front end portion 30c1 of the third recess 30c having the highest axial height in the cam follower member 30 and being switched to the first recess 30a having the lowest axial height, it is possible to prevent a large impact from occurring.

[0113] Further, in the present embodiment, the stopper which restricts the movement of the cam member 31 to the suspension spring S side is provided as the annular stopper ring 45, but the stopper is not particularly limited as long as it is able to restrict the movement of the cam member 31 to the suspension spring S side, and for example, it can be a protrusion which protrudes in the radial direction from the second mounting shaft portion 42 of the shaft 4.

[0114] Further, the stopper which restricts the movement of the cam member 31 to the suspension spring S side can be provided to other than the shaft 4, and for example, it can be provided to the inner periphery of the vehicle body side tube 1.

[0115] Further, in the present embodiment, by rotating the dial 5 in the clockwise direction to rotate the cam member 31 in the clockwise direction via the shaft 4, it is possible to increase the initial load of the suspension spring S, but it is also possible to increase the initial load of the suspension spring S by rotating the dial 5 in the counterclockwise direction. In this case, the plurality of protrusions 31a, 31b, 31c provided to the upper end of the cam member 31 can be arranged so that the axial height is lowered in stages in the counterclockwise direction as viewed from the side of the dial 5, and the plurality of recesses 30a, 30b, 30c provided to the lower end of the cam follower member 30 can be arranged so that the axial height is raised in stages in the counterclockwise direction as viewed from the side of the dial 5.

[0116] Further, in the present embodiment, the front fork F is provided with a cylindrical cover 6 that is inserted into the vehicle body side tube 1 and closes the vehicle body side opening of the vehicle body side tube 1, the shaft 4 restricts the axial movement of the cover 6 and is relatively rotatably held, and the cam device 3 has a cam follower member 30 that is fixedly coupled to one end of the cover 6 so as to be relatively non-rotatable and accommodated in the vehicle body side tube 1, and a cam member 31 that is interposed between the cam follower member 30 and the suspension spring S, and in a state in which the shaft 4 is inserted into the inside of the cover 6 and the cam follower member 30 and the cam member 31, a stopper ring 45 that is a stopper to prevent the cam member 31 from falling off the shaft 4 is provided on the outer periphery of the shaft 4.

[0117] According to this configuration, the cover 6 and the cam follower member 30 and the cam member 31 can be assembled on the outer periphery of the shaft 4 and modularized. Further, the shaft 4 is relatively rotatably held in a state in which the axial movement of the cover 6 with respect to the shaft 4 is restricted, so that the cover 6 and the cam follower member 30 and the cam member 31 only need to be assembled on the outer periphery of the shaft 4 and modularized, and then the cover 6 is installed in the vehicle body side opening of the vehicle body side tube 1, so that the adjuster A can be provided at the upper end of the vehicle body side tube 1. Therefore, according to the above-described configuration, the assembly of the front fork F is easier.

[0118] Further, in the present embodiment, the stopper to prevent the cam member 31 from falling off the shaft 4 is provided as the annular stopper ring 45, but the stopper is not particularly limited as long as it can prevent the cam member 31 from falling off the shaft 4, and for example, it can be a protrusion that protrudes radially from the second mounting shaft portion 42 of the shaft 4.

[0119] Further, in the present embodiment, the stopper ring 45 has both the functions of the stopper that restricts the movement of the cam member 31 to the side of the suspension spring S by an amount greater than the maximum, and the stopper that prevents the cam member 31 from falling off the shaft 4, but it can have only one of the functions.

[0120] Further, in the present embodiment, the shaft 4 restricts the axial movement of the cover 6 and is relatively rotatably held by clamping the cover 6 with the snap rings 43 and 44 that are respectively mounted on the outer periphery of the upper end and the lower end of the first mounting shaft portion 41, but the cover 6 can be relatively rotatably held with respect to the shaft 4 by restricting the axial movement of the cover 6 by other methods.

[0121] The above-described preferred embodiments of the present application have been described in detail, but modifications, variations, and changes can be made without departing from the scope of the application. Symbol Explanation

[0122] 1 Vehicle body side tube 2 Axle side tube 3 Cam device 4 Shaft 5 Dial (operation portion) 6 Cover 30 Cam follower member 30A, 30B recess groups 30a, 30b, 30c recesses 31 cam member 31A, 31B protrusion groups 31a, 31b, 31c protrusions 45 stopper ring (stopper) S suspension spring T pipe member (telescopic member)

Claims

1. A front fork comprising: a telescopic member having a body side tube and an axle side tube axially movable relative to the body side tube; a suspension spring accommodated in the telescopic member and urging the vehicle body side tube and the axle side tube in a direction to separate them; a cam device housed in the vehicle body side tube to support one end of the suspension spring and having an annular cam member that moves axially in stages by rotating in the circumferential direction; a shaft inserted into the vehicle body side tube so as to be rotatable in the circumferential direction and having one end connected to the cam member; and A manually operable operating portion is provided on the other end side of the shaft and is arranged outside the vehicle body side tube.

2. The front fork according to claim 1, wherein: The cam device includes an annular cam follower fixedly accommodated in the vehicle body side tube, and the cam member interposed between the cam follower and the suspension spring. The cam component has a plurality of protrusions with different axial heights in the circumferential direction. The cam follower has a plurality of recesses having different axial heights in the circumferential direction and capable of fitting with the protrusions.

3. The front fork according to claim 2, wherein: The cam member has a plurality of protrusion groups, which have the plurality of protrusions and are arranged along the circumferential direction. The cam follower has the same number of recess groups as the protrusion groups, and the cam follower has the plurality of recesses and is arranged at positions facing the respective protrusion groups in the axial direction. Among the plurality of protrusion groups and the plurality of recess groups, one protrusion group and one recess group and another protrusion group and another recess group have the same number of protrusions and recesses fitted with each other.

4. The front fork according to claim 1, wherein: The cam device is formed of synthetic resin.

5. The front fork according to claim 2, wherein The plurality of protrusions are arranged such that their axial height gradually decreases in one circumferential direction when viewed from the operating portion. The plurality of recesses are arranged such that their axial height increases stepwise in the one circumferential direction when viewed from the operating portion. A stopper is provided on the outer periphery of the shaft or the inner periphery of the vehicle body side tube, and the stopper abuts against the suspension spring side end of the cam component to restrict the cam component from moving toward the suspension spring side during a period from when the protrusion with the highest axial height is engaged with the recess with the highest axial height to when the cam component is spaced apart from the cam follower component to the maximum extent.

6. The front fork according to claim 1, wherein: The front fork includes a cylindrical cover that is inserted into the vehicle body side tube and closes the vehicle body side opening of the vehicle body side tube. The shaft restricts the axial movement of the cover and holds the cover in a relatively rotatable manner. The cam device includes a cam follower member fixedly accommodated in the vehicle body side tube and connected to one end of the cover in a relatively non-rotatable manner, and the cam member interposed between the cam follower member and the suspension spring. A stopper is provided on the outer periphery of the shaft, and the stopper prevents the cam member from falling off the shaft when the shaft is inserted through the cover, the cam follower, and the cam member.

Images