JP2005263000A - Front wheel suspension device for bicycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a shock absorbing characteristic not only in backward rocking but also in forward rocking of a rocking arm, in a front wheel suspension device for a bicycle. <P>SOLUTION: This front wheel suspension device 10 for the bicycle regulates rocking to the vehicle body rear side of the rocking arm 30 by arranging a rear stopper mechanism part 70 having an elastic body such as rubber between the rocking arm 30 and a bottom part of a front fork 20, and regulates rocking to the vehicle body front side of the rocking arm 30 by arranging a front stopper mechanism part 80 having an elastic body such as rubber between the rocking arm 30 and a front part of the front fork 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a front wheel suspension device for a bicycle.

  In Patent Documents 1 and 2, in a bicycle front wheel suspension device, left and right front forks are coupled to the lower end portion of a stem shaft that is pivotably supported in a head pipe at the front of a vehicle body, and the front ends of the left and right front forks. An elastic body that gives elastic force to the swing motion in the front-rear direction is interposed in each of the shaft support portions, and the swing arm is pivotally supported, and the front wheel is rotationally supported on the lower end portion of the left and right swing arms. In addition to supporting the axle, the front fork of the front fork is provided vertically above the axle.

  In [0020] and FIG. 7 of Patent Document 1, the housing 31 of the front fork 5 is provided with stopper portions 31a and 31a that serve as a rear stopper and a front stopper, and the swing arm 24 is brought into metal contact with the stopper portions 31a and 31a. The thing which controls rocking is disclosed. As shown in FIG. 12A, the buffering characteristic (torsional torque characteristic) imparted to the swing arm 24 is a characteristic that rises at a stroke after metal contact.

  In FIG. 18 of Patent Document 1, in FIG. 18, a stopper portion 231 b is provided on the inner periphery of the housing of the front fork 5, and front and rear convex portions 224 c are respectively provided at two positions sandwiching the stopper portion 231 b on the outer periphery of the swing arm 24. Is provided, and swinging is restricted by bringing the convex portions 224c and 224c of the swing arm 24 into metal contact with the stopper portion 231b. The buffering characteristic (torsional torque characteristic) imparted to the swing arm 24 is a characteristic that rises at a stroke after metal contact, as shown in FIG.

  In [0042] and FIG. 19 of Patent Document 1, it is considered that the front convex portion 324c provided on the outer periphery of the swing arm 324 discloses the front stopper, and the rear convex portion 324d discloses the rear stopper. However, since the elastic body 341 that exerts an elastic force in the rotational direction on the swing arm 324 in the swinging process of the swing arm 324 is used as a stopper rubber with which the convex portions 324c and 324d abut, As shown in FIG. 12B, the buffering characteristic generated by the protrusion 324c abutting against the elastic body 341 when the 324 swings forward depends on the rubber reaction force of the elastic body 341 itself. . Therefore, for example, even if an attempt is made to provide a progressive buffering characteristic that rises sharply in the latter half of the swing stroke of the swing arm 324, a reaction force greater than the rubber reaction force of the elastic body 341 itself cannot be generated, and the rubber reaction force The characteristics cannot be changed or controlled.

[0017] of Patent Document 2 discloses a structure in which a swing stopper 21 is provided with a rear stopper portion 31a including a rubber 31b. In this device, in addition to the main body (rubber portion) 41a of the elastic body 41 that exerts an elastic force in the rotational direction on the swing arm 21 in the swinging process of the swing arm 21, a stopper rubber 31b is separately provided. The buffering characteristics can be changed in the swing stroke region after 31 a comes into contact with the bottom surface 5 a of the front fork 5. For example, in the swing stroke region after the stopper portion 31a comes into contact with the bottom surface 5a of the front fork 5, the reaction force of the rubber 31b of the stopper portion 31a on the rubber reaction force of the main body (rubber portion) 41a of the elastic body 41 itself. In addition, a progressive composite buffer characteristic that rises sharply in the latter half of the swing stroke of the swing arm 21 can be exhibited, thereby improving the controllability of the vehicle body and stabilizing the vehicle behavior. However, since this does not include a float stopper mechanism that restricts the swinging of the swinging arm 21 forward, it is not possible to change or control the buffering characteristics when swinging forward. Therefore, ride comfort and handling stability cannot be controlled.
Patent 2598753 JP 11-278352 A

  An object of the present invention is to control a shock-absorbing characteristic not only when the swing arm swings backward, but also when swinging forward, in a bicycle front-wheel suspension system.

  According to the first aspect of the present invention, the left and right front forks are coupled to the lower end portion of the stem shaft pivotally supported in the head pipe at the front of the vehicle body, and the front and rear direction forks of the left and right front forks are respectively connected in the front-rear direction. An elastic body that gives elastic force to the swinging motion is interposed to pivotally support the swinging arm. The lower end of the left and right swinging arm supports the axle that supports the front wheel and the front fork. In a bicycle front wheel suspension apparatus in which the tip shaft support is provided vertically above the axle, a rear stopper mechanism having an elastic body such as rubber is provided between the swing arm and the bottom of the front fork, and the swing A front stopper mechanism having an elastic body such as rubber is provided between the swing arm and the front fork to restrict the swing of the moving arm toward the rear side of the vehicle body. It is obtained by restricting the swinging of the vehicle body front side of the arm.

  According to a second aspect of the present invention, in the first aspect of the present invention, a support portion that is offset forward is provided on each of the tip shaft support portions of the left and right front forks, and the elastic shaft is supported on the outer periphery of the support shaft supported by the support portion. A boss portion of the oscillating arm is pivotally supported with a body interposed therebetween, and the rear stopper mechanism portion is a rear arm provided radially at the rear portion of the outer periphery of the boss portion, and a rear stopper provided at the bottom portion of the front fork. And a rear stopper rubber provided on the rear stopper portion or the rear arm, and the front stopper mechanism portion extends radially in front of the outer periphery of the boss portion, and the support portion. A front stopper portion formed on the upper portion and a front stopper rubber provided on the front stopper portion or the front arm.

  According to a third aspect of the invention, in the second aspect of the invention, a brake mounting arm is integrally formed on an upper portion of a support portion provided on the front fork, and the front stopper portion is formed on a front surface of the brake mounting arm. Is.

  According to a fourth aspect of the present invention, in the second or third aspect of the present invention, the rear stopper rubber and / or the front stopper portion is formed with a recess for restricting the diameter of the rear stopper rubber or the front stopper rubber. is there.

(Claim 1)
(a) In addition to the rear stopper mechanism having the rear stopper rubber, the front stopper mechanism having the front stopper rubber is provided, so that not only when the swinging arm swings backward, but also when swinging forward. By simply changing (replacing) the stopper rubber, it is possible to change the buffering characteristics in the swing stroke area after the stopper rubbers have been engaged. Therefore, ride comfort and handling stability can be controlled.

  (b) Since the annular elastic body itself that exerts an elastic force in the rotational direction on the swinging arm in the swinging process of the swinging arm has no damping force, the rear stopper is moved after the swinging arm swings backward. The reaction force of the rubber causes the swing arm to swing back. In this case, the front stopper rubber can buffer or restrict the swing back to the front.

(Claim 2)
(c) A rear arm is formed at the rear of the boss of the swing arm in the radial direction, a rear stopper is formed at the bottom of the front fork, and the front arm is positioned at the front of the boss of the swing arm in the radial direction. The front stopper is formed on the upper part of the support provided on the front fork. As a result, the swing axis of each arm coincides with the axis of each stopper, and the swing radius of each arm can be reduced, so that each stopper mechanism can have a compact structure.

(Claim 3)
(d) Since the brake mounting arm is provided on the upper part of the support provided on the front fork and the front stopper is formed on the front surface of this brake mounting arm, no special members are required to form the front stopper, and the manufacturing cost Can be lowered.

(Claim 4)
(e) Since the recess for restricting the diameter expansion of the stopper rubber is formed in each of the rear stopper portion and the front stopper portion, the stopper rubber can be prevented from protruding outward in the radial direction.

  1 is a perspective view showing a front wheel suspension device, FIG. 2 is a side view showing the front wheel suspension device, FIG. 3 is a front view showing the front wheel suspension device, FIG. 4 is a rear view showing the front wheel suspension device, and FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5, FIG. 7 is a front shaft support portion of the front fork, (A) is a cross-sectional view, and (B) is B- in (A). FIG. 8 is a cross-sectional view taken along line B, FIG. 8C is an enlarged view of a main part of FIG. 8A, FIG. 8 is a cross-sectional view showing a modification of the front end shaft support portion of the front fork, and FIG. FIG. 10 is a cross-sectional view showing a modified example of the front shaft support portion of the front fork, FIG. 11 is a diagram showing the buffer characteristic of the front fork, and FIG. 12 is a diagram showing the buffer characteristic of the conventional front fork. .

  As shown in FIGS. 1 to 4, the front wheel suspension device 10 for a bicycle has left and right front forks 20 and 20 coupled to a lower end portion of a stem shaft 12 pivotally supported in a head pipe 11 at the front portion of a vehicle body. doing.

  Each of the left and right front forks 20 and 20 is provided with a support portion (holder portion) 22 that is offset forward (forward along the traveling direction of the vehicle body) from the center axis C that extends straightly at each of the front end shaft support portions 21. A boss portion 31 of the swing arm 30 is pivotally supported on a support shaft 23 fixed to the left and right support portions 22. The swing arm 30 is supported by the support shaft 23 with an elastic body 40 that applies elastic force (reaction force) to the swing arm 30 with respect to the swing motion in the front-rear direction.

  The front shaft support portion 21 of the front fork 20 is inserted into the shaft hole 32 provided in the boss portion 31 of the swing arm 30 by inserting the support shaft 23 supported in a fixed state on the support portion 22, on the outer periphery of the support shaft 23. The shaft hole 32 of the swing arm 30 is pivotally supported with the elastic body 40 interposed.

  An axle 34 that rotatably supports the front wheel is fixedly supported in the mounting groove 33 at the lower end of the left and right swing arms 30. When an impact from the road surface does not act on the front wheel, the swing arm 30 stands vertically, the front end shaft support portion 21 (support shaft 23) of the front fork 20 is positioned vertically above the axle 34, and the axle 34 is located on the support shaft 30. Positioned vertically below.

Therefore, the buffering action by the front wheel suspension device 10 is performed as follows.
(1) When the bicycle is traveling on a flat road surface, there is no impact on the front wheels, so the swing arm 30 is kept in a vertical position and does not have a buffering action.

  (2) When the bicycle rides over the bumps on the road surface, the front wheel is impacted from directly below and from the front. The swing arm 30 that supports the axle 34 that supports the front wheel swings around the support shaft 23 backward while twisting the elastic body 40 to swing the front wheel rearward, and the impact from the front is rearward. And let the impact from right below escape upward. As a result, the impact from directly below and the impact from the front are buffered.

  (3) When the front wheel gets over the protrusion, the front wheel swings backward according to the above (2), and then swings in the opposite direction due to the torsional reaction of the elastic body 40 and returns to the front. As a result, the energy stored in the elastic body 40 by swinging the front wheel is returned to the rotation of the front wheel, and the loss of travel energy is greatly reduced.

  (4) When braking is applied to the front wheel, the front wheel is subjected to an impact from the front in the same manner as when overcoming the protrusion. This impact is released backward by the front wheels swinging in the same manner as in (2) above.

  However, in the front wheel suspension device 10, (A) a structure for restricting the twisting motion of the axle 34 supported by the swing arm 30, (B) a buffer structure for swinging the swing arm 30, and (c) the stem shaft 12. Each of the non-offset structures of the front fork 20 is provided as follows.

(A) Structure for restricting the twisting motion of the axle 34 supported by the swing arm 30 The front wheel suspension device 10 swings around the outer periphery of the support shaft 23 of the support portion 22 in each of the tip shaft support portions 21 of the left and right front forks 20. Between the inner periphery of the shaft hole 32 of the arm 30, at least one end side of the elastic body 40, in this embodiment, the outer end side (outside the vehicle width direction of the both ends in the axial direction of the elastic body 40 in the vehicle width direction). An annular ring 50 is fitted on the outer end (the inner end is the outer end and the inner end is the inner end). By the annular ring 50 on the left front fork 20 side and the annular ring 50 on the right front fork 20 side, the movement of the axle 34 that pivotally supports the front wheel (the twisting movement) is restricted. The twisting motion is a tilting motion in which both ends of the axle 34 in the vehicle width direction are alternately lowered in a vertical plane around the center point of the axle 34 in the vehicle width direction upon receiving a dancing input when the bicycle is dancing. Say.

  As shown in FIG. 7, the elastic body 40 includes an outer cylinder (collar) 41, an inner cylinder 42 having a wider width (axial width) at both ends than the outer cylinder 41, an inner periphery of the outer cylinder 41, and an inner cylinder 42. The elastic member assembly 40A includes an elastic member 43 such as rubber that is baked and bonded to each of the outer circumferences. The elastic member 43 gives an elastic force to the swinging motion of the swinging arm 30 in the front-rear direction. In the elastic member assembly 40A, the hexagonal inner periphery of the inner cylinder 42 is deformed into the hexagonal outer periphery of the support shaft 23 of the front fork 20 (FIG. 7B), and the shaft hole 32 of the swing arm 30 is inserted. The outer periphery of the outer cylinder 41 is press-fitted into the inner periphery of the support shaft 23 and interposed between the support shaft 23 and the shaft hole 32. The elastic member assembly 40 </ b> A has a hexagonal inner periphery of the inner cylinder 42 deformed into the hexagonal outer periphery of the support shaft 23 of the front fork 20, and the inner periphery of the shaft hole 32 of the swing arm 30. A rubber between the support shaft 23 and the shaft hole 32 is obtained by fitting the outer periphery of the outer cylinder 41 in a deformed shape such as a hexagon or by detachably fitting it in the axial direction via a detent means such as a key. The elastic member assembly 40A including the elastic member 43 having different characteristics may be replaceable.

  The annular ring 50 is disposed on the side of the outer end side of the elastic member 43 in the annular gap between the inner periphery of the outer cylinder 41 and the outer periphery of the inner cylinder 42 constituting the elastic member assembly 40A. Are respectively fitted to the outer cylinder 41 and the inner cylinder 42 so as to be rotatable relative to the outer cylinder 41 and the inner cylinder 42. However, the annular ring 50 may have a slight gap between the inner periphery of the outer cylinder 41 and the outer periphery of the inner cylinder 42.

  A center screw shaft 61 of the cap 60 is screwed onto the free end side of the support shaft 23 of the front fork 20 in which the elastic member assembly 40A is fitted. The side surface of the cap 60 is brought into contact with the end surface of the inner cylinder 42 of the elastic member assembly 40A, and is fastened to the support shaft 23 of the front fork 20 with a predetermined torque. Accordingly, the annular ring 50 is fitted between the elastic member 43 and the cap 60 without receiving the tightening load of the cap 60 and being fixed in the axial direction around the inner cylinder 42. Thereby, the side surface around the screw shaft 61 of the cap 60 is fixed by sandwiching the inner cylinder 42 of the elastic member assembly 40 </ b> A between the side surface around the support shaft 23 in the support portion 22 of the front fork 20 and elastic. The annular ring 50 arranged near the outer end side of the member 43 is prevented from coming off.

  When the annular ring 50 is fitted on the outer end side of the elastic body 40 (elastic member 43), an annular gap formed on the outer end side of the outer cylinder 41 in the annular ring 50 as shown in FIG. (The gap between the inner circumference of the outer cylinder 41 and the outer circumference of the annular ring 50 and the gap between the side face of the annular ring 50 and the side face of the cap 60) are closed to prevent the outside dust from entering the outer cylinder 41.

  The annular ring 50 is preferably made of a synthetic resin, and more preferably made of polytetrafluoroethylene. However, the annular ring 50 may be made of metal.

  In the modified example of FIG. 8, a support shaft 35 (corresponding to the support shaft 23 of the front fork 20) is fixed to the base end portion of the swing arm 30, and the support shaft 35 is supported by the tip shaft support portion 21 of the front fork 20. 22 is inserted into a shaft hole 24 (corresponding to the shaft hole 32 of the swing arm 30), and an elastic body 40 (elastic member assembly 40A) is interposed between the support shaft 35 and the shaft hole 24. The cap 60 is screwed onto the support shaft 35, and the annular ring 50 is prevented from coming off on the side surface of the cap 60. Further, the inner cylinder 42 of the elastic member assembly 40A is sandwiched and fixed between the side surface around the support shaft 35 of the swing arm 30 and the side surface around the screw shaft 61 of the cap 60, and the annular ring 50 is elastically fixed. The ring 43 is fitted on the outer end side of the member 43 to prevent the annular ring 50 from coming off on the side surface of the cap 60.

  In the modification of FIG. 9, annular rings 50 and 50 are fitted to both ends of the elastic body 40 (elastic member assembly 40 </ b> A) in each of the front end shaft support portions 21 of the left and right front forks 20. However, in the shaft support portions 21 of the left and right front forks 20, the annular ring 50 is fitted only on the outer end side of the elastic body 40 (elastic member assembly 40A) (FIGS. 6 and 7) or the elastic body 40 ( It may be fitted only on the inner end side of the elastic member assembly 40A). Further, in the front end shaft support portion 21 of the left and right front forks 20, the annular ring 50 is fitted only on the outer end side of the elastic body 40 (elastic member assembly 40A), and the front end shaft support portion 21 of the left and right front fork 20 is provided. Then, the annular ring 50 may be fitted only on the inner end side of the elastic body 40 (elastic member assembly 40A). In any of these examples, the twisting motion of the axle 34 supported by the swing arm 30 can be restricted.

  10 does not use the elastic member assembly 40A having the outer cylinder 41 and the inner cylinder 42 as the elastic body 40, but the outer periphery of the support shaft 23 of the front fork 20 and the shaft hole 32 of the swing arm 30. An elastic member 43 such as rubber is directly baked and bonded to the inner periphery.

  Examples of the elastic body 40 (elastic member assembly 40A) include spline teeth formed on the inner periphery of the elastic member 43 such as rubber baked and bonded to the inner periphery of the outer cylinder 41, rubber baked and bonded to the outer periphery of the inner cylinder 42, and the like. The spline teeth formed on the outer periphery of the elastic member 43 may be engaged with each other so as to generate a compression force (elastic force) in the rotation direction.

  The support shaft 23 provided on the support portion 22 of the front shaft support portion 21 of the front fork 20 or the support shaft 35 provided on the base end portion of the swing arm 30 is provided with bolts that are separate from the support portion 22 and the swing arm 30. It may be formed by coupling to the support portion 22 or the swing arm 30.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) During bicycle dancing, the axle 34 is squeezed in a vertical plane around the center point in the axial width direction of the axle 34 (movement in which both ends of the axle 34 are moved downward alternately upon receiving pedaling input). Even in this case, the annular rings 50 of the left and right front forks 20 are arranged on both sides of the center point of the axle 34 (both sides of the front wheel), so that the twisting movement of the axle 34 is restricted. In addition, when the steering wheel is suddenly turned, the twisting movement in the horizontal plane is restricted.

  (b) Since the main body (rubber part) of the elastic body 40 is not sandwiched between the convex part of the support shaft 23 and the convex part of the lid as in the prior art, the rotation direction of the main body (rubber part) depends on the amount of pinching. The elastic force in the rotational direction of the elastic body 40 can be maintained constant, and the characteristics in the rotational direction of the elastic body 40 (rubber portion) can be stabilized.

  (c) Since the annular ring 50 receives an input at the time of pedaling acting in the vertical direction of the elastic body 40, the loss of the input at the time of pedaling can be reduced.

  (d) Between the shaft hole 32 and the support shaft 23, it is only necessary to fit a pair of left and right annular rings 50 sandwiching the front wheel on at least one end side of the elastic body 40. 23 (left and right front forks 20) does not need to be provided with a convex portion 24C and the lid 44 is not provided with a convex portion 44b, so that the structure is simple and the manufacturing cost can be reduced.

  (e) Since the elastic member assembly 40A in which the elastic member 43 such as rubber is provided between the inner cylinder 42 and the outer cylinder 41 in advance is prepared as the elastic body 40, the elastic member 40 is provided between the shaft hole 32 and the support shaft 23. The assembling property of the elastic body 40 is improved.

  (f) Since the annular ring 50 is prevented from coming off at the tip of the cap 60 or the left and right front forks 20, the side surface of the swing arm 30, or the side surface of the cap 60, the annular ring 50 does not fall off in the axial direction.

  (g) Since the annular ring 50 is fitted to both end sides of the elastic body 40, it is possible to reliably suppress the twisting motion and pedaling input.

  (h) Since the annular ring 50 is provided only on the outer end side or the inner end side of the elastic body 40, the number of parts can be reduced as compared with the case where it is provided on both end sides, and the cost is reduced.

  (i) Since the annular ring 50 closes the annular gap formed on the outer end side of the outer cylinder 41, it is possible to suppress the entry of dust and the like into the outer cylinders 41 from the outside.

  (j) Since the annular ring 50 made of synthetic resin is used, no contact sound or the like is generated compared to the case where the annular ring 50 made of metal is used.

  (k) Since the annular ring 50 is made of polytetrafluoroethylene, the friction coefficient is reduced, and the generation of friction accompanying the swing of the swing arm 30 can be reduced.

(B) Shock Absorbing Structure for Swinging of Swing Arm 30 As shown in FIGS. 1 to 5, the front-wheel suspension device 10 includes a swing arm 30 and a front fork 20 at each of the front end shaft support portions 21 of the left and right front forks 20. A rear stopper mechanism portion 70 having an elastic body such as rubber (a rear stopper rubber 73 described later) is provided between the bottom portion and the swinging arm 30 to restrict the swinging of the swinging arm 30 toward the rear side of the vehicle body. At the same time, a front stopper mechanism portion 80 having an elastic body such as rubber (a front stopper rubber 83 described later) is provided between the swing arm 30 and the front portion of the front fork 20, and the swing arm 30 toward the front side of the vehicle body. The swing of the is regulated.

  The rear stopper mechanism part 70 is provided at the rear part of the outer periphery of the boss part 31 of the swing arm 30 and on the rear arm 71 extending in the radial direction and on the bottom part of the front fork 20 (the front end surface on the central axis of the front fork 20). The rear stopper 72 and a rear stopper rubber 73 fixed to the rear arm 71 are included. A recess 72 </ b> A that restricts the diameter of the rear stopper rubber 73 is formed in the rear stopper 72. Around the swing axis (support shaft 23) of the swing arm 30, the recess 72A of the rear stopper 72 and the rear stopper rubber 73 are provided at the same radial position.

  The front stopper mechanism 80 includes a front arm 81 extending in the radial direction at a front portion of the outer periphery of the boss 31 of the swing arm 30, and a front stopper 82 formed on the support 22 of the front fork 20. The front stopper rubber 83 is fixed to the front arm 81. The front stopper portion 82 forms a recess 82 </ b> A that restricts the diameter of the front stopper rubber 83. Around the swing shaft (support shaft 23) of the swing arm 30, the recess 82A of the front stopper portion 82 and the front stopper rubber 83 are provided at the same radial position.

  The front wheel suspension device 10 has a brake mounting arm 25 integrally formed on an upper portion of a support portion 22 provided on the front fork 20, and a front stopper portion 82 of a front stopper mechanism portion 80 is formed on the front surface of the brake mounting arm 25. is there.

  The rear stopper mechanism unit 70 is configured so that a vertical line L connecting the support shaft 23 and the axle 34 when the swing arm 30 stands vertically when the rear stopper rubber 73 of the rear arm 71 abuts the recess 72A of the rear stopper unit 72, Allow to swing about 30 degrees backward. The front stopper mechanism 80 allows the above-described vertical line L to swing forward about 15 degrees when the front stopper rubber 83 of the front arm 81 abuts the recess 82A of the front stopper 82.

  According to the front wheel suspension device 10, the elastic body 40 (the elastic member assembly 43) is in the backward swing stroke region after the rear stopper rubber 73 of the rear stopper mechanism portion 70 contacts the recess 72 </ b> A of the rear stopper portion 72. The reaction force of the rear stopper rubber 73 is added to the rubber reaction force, and a progressive composite buffering characteristic that rises sharply in the latter half of the backward swing stroke of the swing arm 30 is exhibited. Further, in the forward swing stroke region after the front stopper rubber 83 of the front stopper mechanism 80 abuts the recess 82A of the front stopper 82, the rubber reaction force of the elastic body 40 (elastic member assembly 43) is affected. Further, the reaction force of the front stopper rubber 83 is applied, and a progressive composite buffer characteristic that rises sharply in the latter half of the forward swing stroke of the swing arm 30 is exhibited. As a result, as shown in FIG. 11, not only when the swing arm 30 swings backward, but also when the forward swinging is controlled, the vehicle body behavior can be stabilized. Therefore, riding comfort and steering stability can be controlled.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) Since the front stopper mechanism portion 80 having the front stopper rubber 83 is provided in addition to the rear stopper mechanism portion 70 having the rear stopper rubber 73, not only when the swing arm 30 swings backward but also forward. Even when the stopper rubbers 73 and 83 are swung, only the stopper rubbers 73 and 83 are changed (replaced), so that the buffering characteristics in the swing stroke region after the stopper rubbers 73 and 83 abut can be made variable. Therefore, ride comfort and handling stability can be controlled.

  (b) Since the annular elastic body 40 itself that exerts an elastic force in the rotational direction on the swing arm 30 in the swinging process of the swing arm 30 has no damping force, the swing arm 30 swings backward. Thereafter, the swinging arm 30 swings back due to the reaction force of the rear stopper rubber 73. In this case, the front stopper rubber 83 can buffer or restrict the swing back to the front.

  (c) A rear arm 71 is formed on the rear portion of the boss portion 31 of the swing arm 30 so as to extend in the radial direction, a rear stopper portion 72 is formed on the bottom portion of the front fork 20, and the front of the boss portion 31 of the swing arm 30 is formed. A front arm 81 is formed extending in the radial direction at the portion, and a front stopper portion 82 is formed on the upper portion of the support portion 22 provided on the front fork 20. As a result, the pivot axis of each arm 71, 81 and the axis of each stopper part 72, 82 coincide, and the pivot radius of each arm 71, 81 can be reduced, so that each stopper mechanism part 70, 80 can have a compact structure.

  (d) Since the brake mounting arm 25 is provided on the upper portion of the support portion 22 provided on the front fork 20, and the front stopper portion 82 is formed on the front surface of the brake mounting arm 25, a special member is used when forming the front stopper portion 82. This is not necessary and the production cost can be reduced.

  (e) Since the concave portions 72A and 82A for restricting the diameter expansion of the stopper rubbers 73 and 83 are formed in the rear stopper portion 72 and the front stopper portion 82, respectively, radially outwards centering on the shaft holes of the stopper rubbers 73 and 83. Can prevent overhang.

(C) Non-offset structure of the front fork 20 with respect to the stem shaft 12 The front wheel suspension device 10 couples the left and right front forks 20 to the stem shaft 12 without being offset in the longitudinal direction of the vehicle body. That is, the center axis C of the left and right front forks 20 is straight, and the center axes of both front forks 20 are positioned in a plane in the vehicle width direction including the extension line of the center axis of the stem shaft 12.

  The swinging trajectory of the axle 34 when the axle 34 supported in the mounting groove 33 of the swinging arm 30 swings from the vertically lower side with respect to the tip shaft support portion 21 of the front fork 20 to the rear of the vehicle body is substantially the same as that of the stem shaft 12. The swing arm 30 is offset forward from the center axis C of the front fork 20 so as to be positioned on the extension (on the extension area A of the diameter of the stem shaft 12), and is pivotally supported on the front end pivot portion 21 of the front fork 20. (FIGS. 2 and 5).

  Note that, as described above, the front wheel suspension device 10 is provided with a support portion 22 that is offset forward on each of the front end shaft support portions 21 of the left and right front forks 20, and an elastic body on the outer periphery of the support shaft 23 supported by the support portion 22. 40 (elastic member assembly 40A) is interposed to support the boss portion 31 of the swing arm 30, and a rear arm 71 is provided extending radially in the rear portion of the outer periphery of the boss portion 31. A rear stopper 72 is provided at the bottom, a rear stopper rubber 73 is provided on the rear arm 71, and a recess 72A in which the rear stopper rubber 73 abuts is provided in the rear stopper 72.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) Since the trajectory of the axle 34 with respect to the road surface input from the front is always on the extension of the diameter of the stem shaft 12 and the front fork 20 is not offset to the stem shaft 12, the input from the road surface is the front fork 20 Is efficiently transmitted to the stem shaft 12 through the rider, increasing the rider's sense of security.

  (b) The rear stopper rubber 73 is provided on the rear stopper 72 provided on the bottom of the front fork 20 or the rear arm 71 provided on the swing arm 30, and the front fork 20 is not offset to the stem shaft 12. Therefore, the bump load when the swing arm 30 swings backward is efficiently transmitted to the stem shaft 12 via the front fork 20 and the rider's feeling of security increases.

  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 perspective view showing a front wheel suspension device. FIG. 2 is a side view showing the front wheel suspension device. FIG. 3 is a front view showing the front wheel suspension device. FIG. 4 is a rear view showing the front wheel suspension device. FIG. 5 is an enlarged view of a main part of the front wheel suspension device. 6 is a cross-sectional view taken along line VI-VI in FIG. 7A and 7B show the front shaft support portion of the front fork, in which FIG. 7A is a cross-sectional view, FIG. 7B is a cross-sectional view taken along line BB in FIG. . FIG. 8 is a cross-sectional view showing a modification of the front end shaft support portion of the front fork. FIG. 9 is a cross-sectional view showing a modification of the front end shaft support portion of the front fork. FIG. 10 is a cross-sectional view showing a modification of the front end shaft support portion of the front fork. FIG. 11 is a diagram showing the buffer characteristics of the front fork. FIG. 12 is a diagram showing the buffer characteristics of a conventional front fork.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Front wheel suspension apparatus 11 Head pipe 12 Stem shaft 20 Front fork 21 Front end shaft support part 22 Support part 23 Support shaft 25 Brake mounting arm 30 Swing arm 31 Boss part 32 Shaft hole 34 Axle 40 Elastic body 70 Rear stopper mechanism part 71 Rear arm 72 Rear stopper Part 72A Concave part 73 Rear stopper rubber 80 Front stopper mechanism part 81 Front arm 82 Front stopper part 82A Concave part 83 Front stopper rubber

Claims (4)

The left and right front forks are connected to the lower end of the stem shaft pivotally supported in the head pipe at the front of the vehicle body,
The swing arm is pivotally supported by interposing an elastic body that gives elastic force to the swing motion in the front-rear direction on each of the front shaft support portions of the left and right front forks.
In the front wheel suspension device for a bicycle, the lower end of the left and right swing arm supports an axle that supports the front wheel as a rotational axis, and the front end fork of the front fork is provided vertically above the axle.
Between the swing arm and the bottom of the front fork, a rear stopper mechanism having an elastic body such as rubber is provided to restrict swing of the swing arm toward the rear of the vehicle body,
A front stopper mechanism having an elastic body such as rubber is provided between the swing arm and the front portion of the front fork to restrict swing of the swing arm toward the front side of the vehicle body. Front wheel suspension system for bicycles. A support portion offset forward is provided on each of the front end shaft support portions of the left and right front forks, and the boss portion of the swing arm is supported on the outer periphery of the support shaft supported by the support portion with the elastic body interposed therebetween. And
The rear stopper mechanism is
A rear arm extending radially in the rear part of the outer periphery of the boss part;
A rear stopper provided at the bottom of the front fork,
It consists of a rear stopper rubber provided on the rear stopper part or the rear arm,
The front stopper mechanism is
A front arm extending radially in front of the outer periphery of the boss,
A front stopper portion formed on the upper portion of the support portion;
The front wheel suspension device for a bicycle according to claim 1, comprising the front stopper portion or a front stopper rubber provided on the front arm.   The bicycle front wheel suspension apparatus according to claim 2, wherein a brake mounting arm is integrally formed on an upper portion of a support portion provided on the front fork, and the front stopper portion is formed on a front surface of the brake mounting arm.   The front wheel suspension device for a bicycle according to claim 2 or 3, wherein the rear stopper portion and / or the front stopper portion is formed with a recess for restricting the diameter of the rear stopper rubber or the front stopper rubber.

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