JP2005240923A - Front fork for two-wheel vehicle or the like - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a front fork for a two-wheel vehicle or the like, having bump rubber spring guide structure for providing a wide range of bump load and preventing obstruction of operation of a suspension spring and generation of abnormal noise caused by catching of the suspension spring. <P>SOLUTION: In the front fork 10 of a two-wheel vehicle or the like, an approximately columnar spring guide 26 made of synthetic resin is disposed to an inner periphery of a suspension spring 23, a recess part 71 is formed to one end of the spring guide 26 to house a base end part of a bump rubber 27, a contour 72 of an outer face of a longitudinal cross-section including a center axis of the spring guide 26 is an approximately circular arc, and outer diameters of both end parts of the spring guide 26 are smaller than an outer diameter of a center part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a front fork for a two-wheeled vehicle or the like used for a small displacement scooter or the like, and more particularly to a front fork for a two-wheeled vehicle or the like provided with a bump rubber that cushions at the time of maximum compression.

As described in Patent Document 1, as a front fork of a motorcycle or the like, an inner tube is formed through a sliding guide tube provided on the inner periphery of the outer tube on the vehicle body side and a piston provided on the outer periphery of the inner tube on the wheel side. An inner tube is slidably inserted into the inner tube, a suspension spring is interposed between the inner tube and the outer tube, and a bump rubber is provided on the inner periphery of the suspension spring. That is, the upper portion of the inner tube 5 is a small-diameter portion 6, and a stopper rubber 12 as a bump rubber is provided at the upper end of the small-diameter portion 6 of the inner tube 5. A cushion spring 13 is interposed between the stopper 4 on the outer tube 1 side.
Shokai 62-88696

The prior art of Patent Document 1 has the following problems.
The stopper rubber 12 absorbs the bump load only by the elastic characteristic of the rubber itself, and cannot absorb a wide range of bump load.

  In general, in such a front fork, the inner periphery of the outer tube and the outer tube between the bush (sliding guide tube) on the inner periphery of the opening of the outer tube and the outer periphery of the inner tube and the outer periphery of the tip of the inner tube. Grease is applied between the circumferences, and the inside of the outer tube and inner tube is made into an air chamber. For this reason, the outer tube and the inner tube do not have an oil chamber. As a result, the silencing effect of the oil chamber on the operating sound of the suspension spring cannot be obtained.

  Therefore, this front fork is provided with a relatively large gap between the suspension spring and the inner periphery of the outer tube in order to prevent the sound generated by the operation of the suspension spring. A cylindrical spring guide is provided on the inner circumference of the suspension spring to prevent contact with the circumference, but since the clearance of the suspension spring with respect to the inner circumference of the outer tube is large, the suspension spring buckles greatly, Snake.

  In addition, the cylindrical portion of this spring guide may be relatively long. When the suspension spring is caught on the outer periphery of this cylindrical portion, the suspension spring operation is hindered or the suspension spring is released. An unusual noise is generated.

  It is an object of the present invention to provide a bump rubber spring guide structure that can obtain a wide range of bump loads and that can prevent the suspension spring from operating or generate abnormal noise due to the suspension spring being caught. The object is to provide a front fork such as a provided motorcycle.

  According to the first aspect of the present invention, the inner tube is slidable in the outer tube via the sliding guide tube provided on the inner periphery of the outer tube on the vehicle body side and the piston provided on the outer periphery of the inner tube on the wheel side. Insert a suspension spring between the inner tube and the outer tube, and in a front fork such as a two-wheeled vehicle provided with a bump rubber on the inner periphery of the suspension spring, the inner periphery of the suspension spring is generally made of synthetic resin. A cylindrical spring guide is provided, and a concave portion for accommodating the base end portion of the bump rubber is formed at one end of the spring guide, and the outline of the outer surface of the longitudinal section including the central axis of the spring guide is substantially arcuate. In addition, the outer diameter of both ends of the spring guide is made smaller than the outer diameter of the central portion.

  According to a second aspect of the present invention, in addition to the first aspect of the invention, the bottom surface of the concave portion formed in the spring guide is substantially spherical.

(Claim 1)
a. The concave part of the spring guide prevents the bump rubber from expanding beyond a certain diameter at the time of maximum compression. As a result, a large bump load can be obtained.

  b. Since the spring guide is formed of synthetic resin and the outer periphery thereof is formed in a barrel shape, the friction exerted on the suspension spring can be reduced, and the suspension spring can be prevented from being caught.

(Claim 2)
c. By making the bottom surface of the concave portion of the spring guide spherical, the stress generated in the concave portion when the bump rubber is prevented from expanding beyond a certain diameter can be dispersed. As a result, the side wall portion of the concave portion can be prevented from cracking.

  1 is a front view showing the shock absorber partially broken, FIG. 2 is a cross-sectional view showing the suspension spring support structure of FIG. 1, FIG. 3 is a cross-sectional view showing the lower spring support, and FIG. FIG. 5 shows a lower spring receiver, (A) is a sectional view, (B) is a side view, FIG. 6 shows an upper spring receiver, (A) is a sectional view, (B) is a plan view, (C) is a side view, FIG. 7 is a sectional view showing the periphery of the sliding guide tube of FIG. 1, FIG. 8 is a perspective view of the sliding guide tube, FIG. 9 shows the sliding guide tube, and (A) is a front view. FIG. 10B is a cross-sectional view taken along line BB, FIG. 10C is a cross-sectional view taken along line CC, FIG. 10 is a longitudinal cross-sectional view showing a spring guide, and FIG. 11 is a side view showing a bump rubber. .

  A shock absorber 10 in FIG. 1 is used as a front fork such as a small displacement scooter, and an outer tube 11 on the vehicle body side is attached to a steering shaft 1 supported on the vehicle body side via upper and lower brackets 2 and 3. . The shock absorber 10 is provided with a sliding guide tube 13 made of a hard synthetic resin such as engineering plastic such as Duracon (trademark of Polyplastics) on the inner periphery of the opening of the outer tube 11, and the inner tube inserted into the outer tube 11. 12 is guided by the sliding guide tube 13.

  Further, as shown in FIG. 2, the shock absorber 10 is provided with a synthetic resin piston 14 that slides on the inner periphery of the outer tube 11 on the outer periphery of the upper end portion of the inner tube 12. 11, two air chambers 15A and 15B are defined above and below the piston 14.

  The shock absorber 10 includes a piston 14 provided on the outer periphery of the distal end portion of the inner tube 12, an inner periphery of the outer tube 11, an inner periphery of the sliding guide tube 13 provided on the outer tube 11, and an outer periphery of the inner tube 12. A grease damper filled with lubricating grease is formed between them. That is, the shock absorber 10 generates a damping force due to the friction between the outer periphery of the piston 14 and the inner periphery of the outer tube 11 and the friction between the inner tube 12 and the sliding guide cylinder 13, and the outer periphery of the piston 14 and the inner tube 11. The proper lubrication is maintained by the grease filled between the circumference and the inner tube 12 and the sliding guide tube 13.

  As shown in FIG. 7, the shock absorber 10 is configured such that the base end large diameter portion 13 </ b> A of the sliding guide cylinder 13 inserted and attached to the inner periphery of the opening portion of the outer tube 11 is the inner periphery of the opening end large diameter portion of the outer tube 11. The back-up ring 15 abutted against the step portion of the base end and seated on the end face of the base end large-diameter portion 13A is locked by a stopper ring 16 attached to the inner periphery of the large-diameter portion at the open end of the outer tube 11. The dust seal 17 is attached to the outer periphery of the open end large diameter portion of the outer tube 11, and the oil seal lip 17 </ b> A and the dust seal lip 17 </ b> B of the dust seal 17 are brought into close contact with the outer periphery of the inner tube 12.

  The shock absorber 10 is provided with cylindrical spring receivers 21 and 22 on the upper end portion of the inner tube 12 and the upper portion of the outer tube 11, respectively, and each end of the suspension spring 23 is arranged on the outer periphery of the spring receivers 21 and 22. Each part is wound and attached.

  Hereinafter, (A) an air vent structure for the upper air chamber 15A of the outer tube 11, (B) a grease circulation structure of the sliding guide cylinder 13, and (C) a bump rubber / spring guide structure will be described.

(A) Air vent structure for the upper air chamber 15A of the outer tube 11 As shown in FIG. 3, the shock absorber 10 forms an air vent passage 31 in the lower spring receiver 21 at the upper end portion of the inner tube 12, and the piston 14 The upper air chamber 15 </ b> A communicates with the outside through the air vent passage 31 and the inner tube 12.

  As shown in FIG. 5, the spring receiver 21 inserts the lower fitting shaft 33 of the annular flange 32 into the upper end inner diameter portion of the inner tube 12, abuts the flange 32 against the upper end surface of the inner tube 12, and the flange 32. The lower end portion of the suspension spring 23 is wound around a spiral groove 34A provided in a part in the circumferential direction of the upper spring winding portion 34 (two arc portions opposed in the diameter direction).

  The spring receiver 21 forms a hollow portion 31A extending over the entire length of the fitting shaft 33 to the spring winding portion 34, and communicates the inner and outer circumferences with the upper end surface of the fitting shaft 33 facing the upper air chamber 15A of the outer tube 11. A groove-like communication part 31B (or a hole-like communication part is acceptable) is formed, and the air vent passage 31 is formed by the hollow part 31A and the communication part 31B. The upper air chamber 15 </ b> A of the outer tube 11 is connected to an air vent passage 31 (hollow portion 31 </ b> A, communication portion 31 </ b> B) of the spring receiver 21, a drain hole 12 </ b> A provided in the inner tube 12, and a lower portion of the inner tube 12. Communicate to the outside.

  In addition, 12B is a guide stay of a brake wire, 12C is a stay for protector attachment, 12D is a brake stopper, and each is fixed to the outer periphery of the lower part of the inner tube 12 by welding.

  A metal collar 24 having a smaller outer diameter than the inner periphery of the outer tube 11 is attached to the upper outer periphery of the inner tube 12, and the fitting shaft 33 of the spring receiver 21 inserted into the upper end inner diameter portion of the inner tube 12, and the inner A fixing pin 25 is inserted like a skewer into a through hole provided in each of the tube 12 and the collar 24. The spring receiver 21 is fixed in both the axial direction and the rotational direction by the fixing pin 25 with the flange 32 abutted against the upper end surface of the inner tube 12. The piston 14 is fitted on the outer periphery of the upper end portion of the inner tube 12 and is sandwiched between the flange 32 of the spring receiver 21 and the collar 24. An annular recess into which the flange 32 is fitted is formed on the upper end surface of the piston 14, and the lower end surface of the piston 14 is seated on the upper end surface of the collar 24.

  A bump rubber 27 is provided on the upper end surface of the spring receiver 21 via a spring guide 26 made of synthetic resin. The bump rubber 27 abuts on the end surface of the upper spring receiver 22 and makes it possible to regulate the maximum compression stroke of the outer tube 11 and the inner tube 12.

  As shown in FIG. 4, the shock absorber 10 has the outer periphery of the cap 28 fixed to the upper end portion of the outer tube 11 by welding, and the upper spring receiver 22 on the upper portion of the outer tube 11 is supported on the back surface of the cap 28. An air vent passage 41 is formed between the upper spring receiver 22 and the cap 28, and the upper air chamber 15 </ b> A of the outer tube 11 communicates with the outside through the air vent passage 41.

  As shown in FIG. 6, the spring receiver 22 includes a protrusion 43 </ b> A provided on a part of the outer periphery of the head 43 by inserting the upper head 43 of the annular flange 42 into the inner diameter of the cap 28 via a gap 41 </ b> A. Is engaged with an anti-rotation recess 28A (not shown) provided on the inner periphery of the cap 28 to prevent the rotation. Further, the spring receiver 22 has a circumferential portion of the spring winding portion 44 at the lower portion of the flange 42 (two arc portions opposed in the diameter direction) in a state where the flange 42 is abutted against the lower end surface of the cap 28. The upper end portion of the suspension spring 23 is wound around the provided spiral groove 44A.

  The spring receiver 22 extends radially outward from the outer peripheral side of the head 43 at a plurality of circumferential positions (for example, three positions) on the upper surface of the flange 42, and on the outer periphery of the flange 42 facing the inner periphery of the outer tube 11. A vent groove 41B is provided. The spring receiver 22 forms an air vent passage 41 by the gap 41A and the ventilation groove 41B. The upper air chamber 15A of the outer tube 11 communicates with the outside through an air vent passage 41 (gap 41A, ventilation groove 41B) of the spring receiver 22.

  A fixing screw 4 inserted through the upper bracket 2 is screwed from the head 43 of the spring receiver 22 to the center of the spring winding portion 44, and the upper bracket 2 is fixed to the upper end surface of the cap 28 of the outer tube 11. Is done.

  In addition, the mounting tube 11A is welded and fixed to a part (intermediate portion) of the outer tube 11 in the axial direction, and the lower bracket 3 is welded and fixed to the intermediate portion of the outer periphery of the mounting tube 11A. The presence of the attachment tube 11 </ b> A prevents welding distortion for attaching the lower bracket 3 to the outer tube 11 on the inner periphery of the outer tube 11 on which the piston 14 slides.

  The suspension spring 23 wound around each of the lower spring receiver 21 and the upper spring receiver 22 functions as a rebound spring that regulates the maximum extension stroke of the outer tube 11 and the inner tube 12, and at the time of maximum extension, the sliding guide cylinder. 13 prevents the upper end surface of 13 from colliding with the lower end surface of the spring guide 26.

Therefore, according to the present embodiment, the following operational effects can be obtained.
a. “By forming an air vent passage 31 in the spring receiver 21 at the upper end of the inner tube 12 and allowing the upper air chamber 15A of the piston 14 to communicate with the outside via the air vent passage 31 and the inner tube 12” When the inner tube 12 is retracted from the outer tube 11 when the shock absorber 10 is extended, the upper air chamber 15A of the piston 14 in the outer tube 11 expands and depressurizes. Outside air is replenished to the upper air chamber 15 </ b> A in the outer tube 11 through the air vent passage 31 of the spring receiver 21 from the gap of the axle mounting portion at the tip.

  As a result, the upper and lower air chambers 15 and 15B of the piston 14 in the outer tube 11 are not depressurized, and mud or the like is formed on the inner peripheral surface of the sliding guide cylinder 13 provided on the inner periphery of the open end of the outer tube 11. No longer inhale.

  b. Since the air vent passage 31 is formed by the hollow portion 31A and the communication portion 31B of the spring receiver 21, the pressure reduction in the shock absorber 10 can be achieved with a simple structure in which the hollow portion 31A and the communication portion 31B are formed in the spring receiver 21. Can be prevented. In addition, since the cylindrical spring receiver 21 is formed by zinc die casting, it does not require additional processing man-hours, and the cost can be reduced by reducing the amount of material used. Become.

  c. By “the upper air chamber 15A of the piston 14 is made to reach the outside through the drain hole 12A provided in the lower part of the inner tube 12”, the water accumulated in the inner tube 12 due to condensation in the inner tube 12 or the like. Since the air vent passage 31 is formed using the existing drain hole 12A for discharging, it is not necessary to process the air vent passage 31 separately. Therefore, the air vent passage 31 can be formed at a low cost without causing an increase in cost.

  d. “Bump rubber 27 is provided on the spring receiver 21 at the upper end of the inner tube 12 via a spring guide 26 made of synthetic resin, and this bump rubber 27 is abutted against the end face of the spring receiver 21 provided on the upper portion of the outer tube 11. As a result, the bump rubber 27 abuts against the end face of the spring receiver 22 on the outer tube 11 side to provide a buffer at the time of maximum compression. The spring guide 26 made of synthetic resin defines an air vent passage 31 between the upper end surface of the spring receiver 21 on the inner tube 12 side and also serves as a guide for the suspension spring 23.

  e. “The air vent passage 41 is provided between the spring receiver 22 on the outer tube 11 side and the cap 28 provided at the upper end portion of the outer tube 11”, whereby the inner circumference of the upper end portion of the spring receiver 22 and the outer tube 11 is provided. A gap 41A is provided between the cap 28 and the cap 28, and the gap 41A is added as an air vent passage 41, so that the pressure reducing effect of the air chambers 15A and 15B in the outer tube 11 can be increased.

(B) Grease circulation structure of the sliding guide tube 13 As shown in FIG. 7, the shock absorber 10 allows the inner tube 12 to slide freely on the sliding guide tube 13 provided on the inner periphery of the opening of the outer tube 11. invite.

  As shown in FIGS. 8 and 9, the sliding guide tube 13 is provided with a grease reservoir hole 51 communicating with the inner and outer circumferences in the axial intermediate portion, and the grease loaded in the grease reservoir hole 51 is disposed on the outer periphery of the inner tube 12. Adhere. On the inner periphery of both the upper and lower ends in the axial direction of the sliding guide tube 13, there are provided upper and lower annular seal members 60 slidably contacting the outer periphery of the inner tube 12, for example, O-rings, and the outer tube 11 and the inner tube 12. During the expansion / contraction stroke, the grease adhering to the outer periphery of the inner tube 12 is scraped off by the seal member 60. The grease on the inner side in the axial direction of the seal member 60 scraped off by the upper and lower seal members 60 passes through the outer periphery of the sliding guide cylinder 13 through the upper and lower circulation paths 53 as shown by arrows in FIG. 51 is communicated.

  Specifically, the sliding guide tube 13 is formed with upper and lower inner peripheral grooves 52 and 52 into which the upper and lower seal members 60 are fitted on the inner periphery of the upper and lower ends in the axial direction. The grease on the inner side in the axial direction of the sealing member 60 is accumulated in the inner circumferential grooves 52. The sliding guide cylinder 13 is formed with upper and lower circulation holes 53A communicating with the inner and outer circumferences of the sliding guide cylinder 13 in the axially inner portion of the seal member 60 in each inner circumferential groove 52, and each circulation hole 53A. The upper and lower circulation grooves 53 </ b> B extending in the axial direction so as to communicate with the grease reservoir hole 51 are formed on the outer periphery of the sliding guide cylinder 13. A circulation path 53 is constituted by the circulation hole 53A and the circulation groove 53B.

  Furthermore, the sliding guide tube 13 forms a wide annular outer peripheral groove 54 in which the grease reservoir hole 51 is opened on the outer periphery of the intermediate portion in the axial direction. A plurality of circulation holes 53 </ b> A communicating the inner and outer circumferences of the sliding guide cylinder 13 are formed in the inner peripheral grooves 52 at both the upper and lower ends of the sliding guide cylinder 13. A plurality of circulation grooves 53B that communicate the plurality of circulation holes 53A with the annular outer circumferential groove 54 are formed in the axial direction.

Therefore, according to the present embodiment, the following operational effects can be obtained.
a. “An annular seal member 60 slidably contacting the outer periphery of the inner tube 12 is provided on the inner periphery of both end portions in the axial direction of the sliding guide tube 13, and grease on the inner side in the axial direction of the seal member 60 is applied to the sliding guide tube 13. The circulation path 53 communicating with the grease reservoir hole 51 is formed via the outer periphery of the sliding guide cylinder 13 ”, whereby the grease adhering to the outer periphery of the inner tube 12 is scraped off by the annular seal member 60, Leakage to the outside of the moving guide cylinder 13 in the axial direction is prevented. Further, the scraped grease passes through the hole 53A of the circulation path 53 formed on the inner side in the axial direction of the seal member 60, is pushed out to the outer peripheral side, and further passes through the outer periphery of the sliding guide tube 13 to be grease. Return to the pool hole 51. That is, the grease circulates through the circulation path 53 of the sliding guide cylinder 13 to the grease reservoir hole 51 and prevents the grease from leaking outside as much as possible.

Therefore, the life of the shock absorber can be extended with a simple and inexpensive configuration.
b. “An annular inner circumferential groove 52 into which the annular sealing member 60 is fitted is formed at both ends of the sliding guide tube 13, and the sliding is performed on the axially inner side of the sealing member 60 in the inner circumferential groove 52. A circulation hole 53A that connects the inner and outer circumferences of the guide cylinder 13 is formed, and a circulation groove 53B that communicates the circulation hole 53A with the grease reservoir hole 51 is formed on the outer periphery of the sliding guide cylinder 13, and the circulation hole 53A and the circulation groove 53B are formed. The grease on the outer periphery of the inner tube 12 scraped off by the seal member 60 is accumulated in the annular inner peripheral groove 52 and further from the circulation hole 53A on the axially inner side of the seal member 60 to the outer peripheral side. To the grease reservoir hole 51 through the circulation groove 53B on the outer periphery.

  As a result, the grease can be held also in the inner circumferential groove 52, so that the seal member 60 is lubricated and a plurality of lubrication points are provided, so that the slidability is increased. Also, grease circulation is ensured.

  c. “On the outer periphery of the sliding guide tube 13, an annular outer peripheral groove 54 in which the grease retaining hole 51 is opened is formed, and a plurality of circulation holes 53 </ b> A communicating the inner and outer periphery of the sliding guide tube 13 with the inner peripheral grooves 52 at both ends. The inner tube scraped off by the seal member 60 is formed on the outer periphery of the sliding guide tube 13 and the plurality of circulation grooves 53B are formed in the axial direction to communicate the plurality of circulation holes 53A with the annular outer periphery groove 54 ". The outer circumferential grease 12 is formed in the inner circumferential grooves 52 at both ends, passes through the plurality of circulation holes 53A, and further circulates through the plurality of circulation grooves 53B to the annular outer circumferential groove 54 where the grease reservoir hole 51 is opened. .

  As a result, the total cross-sectional area of the circulation path 53 is increased, and the grease can be smoothly circulated.

  d. By making the seal member 60 an O-ring, the seal member 60 can be made inexpensive.

(C) Bump Rubber / Spring Guide Structure As shown in FIGS. 1 to 3, the shock absorber 10 is provided with a bump rubber 27 on the upper end surface of the spring receiver 21 at the upper end portion of the inner tube 12 via a spring guide 26. The spring guide 26 and the bump rubber 27 are provided on the inner periphery of the suspension spring 23. The spring guide 26 guides the suspension spring 23 through a slight annular gap on the inner periphery of the suspension spring 23. The bump rubber 27 is supported on the upper surface of the spring guide 26 and abuts with the end surface of the upper spring receiver 22 to restrict the maximum compression stroke of the outer tube 11 and the inner tube 12.

  The bump rubber 27 is made of rubber or the like, and has a generally oval shape as shown in FIG. 11. The base end portion 27A seated on the spring guide 26 and the tip end portion 27B abutting on the upper spring receiver 22 have a substantially spherical convex surface. To do.

  The spring guide 26 is made of a synthetic resin and has a substantially cylindrical shape as shown in FIG. 10. The lower surface seated on the spring receiver 21 is a flat surface, and the upper surface on which the base end portion 27A of the bump rubber 27 is received and seated is a concave portion. 71. The concave portion 71 of the spring guide 26 has a bottom portion 71A on which the bottom surface of the base end portion 27A of the bump rubber 27 is seated without a gap, and a side wall portion 71B on the outer peripheral surface of the base end portion 27A of the bump rubber 27 with a gap therebetween. The bottom surface of the bottom portion 71A is substantially spherical, the inner surface of the side wall portion 71B is a tapered surface that expands outward, and the bottom surface of the bottom portion 71A and the inner surface of the side wall portion 71B are smoothly connected by an arc surface. When the diameter of the bump rubber 27 is increased by contact with the upper spring receiver 22, the bump rubber 27 is restrained in contact with the inner surface of the side wall 71 </ b> B of the concave portion 71 of the spring guide 26, thereby preventing further expansion of the diameter.

  The spring guide 26 has a contour 72 on the outer surface of a longitudinal section (FIG. 10) including the central axis (cylindrical central axis C) that is generally arcuate (in this embodiment, an arc having a radius of curvature of 216 mm), and both ends of the spring guide 26. The outer diameter of the lower surface portion and the upper surface portion is smaller than the outer diameter of the central portion (the outer diameter of the central portion of the spring guide 26 is through a slight annular gap on the inner periphery of the suspension spring 23). In other words, the outer periphery of the spring guide 26 forms a barrel shape.

Therefore, according to the present embodiment, the following operational effects can be obtained.
a. The concave portion 71 of the spring guide 26 prevents the bump rubber 27 from expanding beyond a certain diameter at the time of maximum compression. As a result, a large bump load can be obtained.

  b. Since the spring guide 26 is formed of synthetic resin and the outer periphery 72 thereof is formed in a barrel shape, the friction exerted on the suspension spring 23 can be reduced, and the suspension spring 23 can be prevented from being caught. .

  c. By making the bottom surface 71 </ b> A of the concave portion 71 of the spring guide 26 spherical, it is possible to disperse the stress generated in the concave portion 71 when preventing the bump rubber 27 from expanding beyond a certain diameter. As a result, the side wall 71B of the concave portion 71 can be prevented from cracking.

  When a corner is formed on the bottom surface of the bottom 71A of the concave portion 71 of the spring guide 26, stress is concentrated on the corner, and the side wall 71B is easily broken from the corner.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention.

FIG. 1 is a front view of the shock absorber partially cut away. FIG. 2 is a cross-sectional view showing the suspension spring support structure of FIG. FIG. 3 is a cross-sectional view showing the lower spring support. FIG. 4 is a cross-sectional view showing the periphery of the upper spring bearing. 5A and 5B show a lower spring receiver, where FIG. 5A is a sectional view and FIG. 5B is a side view. 6A and 6B show an upper spring support, FIG. 6A is a sectional view, FIG. 6B is a plan view, and FIG. 6C is a side view. FIG. 7 is a sectional view showing the periphery of the sliding guide cylinder of FIG. FIG. 8 is a perspective view showing a sliding guide tube. 9A and 9B show a sliding guide tube, where FIG. 9A is a front view, FIG. 9B is a cross-sectional view taken along line BB, and FIG. 9C is a cross-sectional view taken along line CC. FIG. 10 is a longitudinal sectional view showing the spring guide. FIG. 11 is a side view showing the bump rubber.

Explanation of symbols

10 Shock absorber (front fork)
11 Outer tube 12 Inner tube 13 Sliding guide tube 14 Piston 23 Suspension spring 26 Spring guide 27 Bump rubber 71 Concave portion 72 Outline

Claims (2)

The inner tube is slidably inserted into the outer tube via a sliding guide tube provided on the inner periphery of the outer tube on the vehicle body side and a piston provided on the outer periphery of the inner tube on the wheel side. In a front fork such as a two-wheeled vehicle with a suspension spring interposed between the tube and a bump rubber provided on the inner periphery of the suspension spring,
A substantially cylindrical spring guide made of synthetic resin is provided on the inner periphery of the suspension spring,
At one end of the spring guide, a concave portion that accommodates the base end portion of the bump rubber is formed, and
A front fork for a two-wheeled vehicle or the like, characterized in that the outer surface of the longitudinal section including the central axis of the spring guide has a generally circular arc shape and the outer diameters of both ends of the spring guide are smaller than the outer diameter of the central part. .   The front fork of a motorcycle or the like according to claim 1, wherein the bottom surface of the concave portion formed in the spring guide is substantially spherical.

Images