JPH09286370A - Bicycle suspension fork and bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce play in rotary direction in a connecting area between first and second fork stems during handlebar operation by disposing plate springs having projections on the inside cylindrical surface of the second fork stem, and a planar member extending in the same direction as the plate springs and having a hole in a position corresponding to the projections on the plate springs. SOLUTION: A key 51 for preventing rotation of a connecting area is passed through the circumference of the middle portion of a pipe portion 42a of a second fork stem 42. The key 51 comprises a pair of plate springs 81 sandwiching a plate member 82. Each of the paired plate springs 81 is formed with a projection 81a. The plate member 82 is formed with a hole 82a in a position corresponding to the projection 81a. The raised portion 81a is made to engage with the hole 82a. Thus, play is reduced during handlebar operation the rotary direction in the connecting area 45 between the first fork stem 41 and the second fork stem 42.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bicycle suspension fork rotatably supported by a bicycle head and a bicycle equipped with the suspension fork.

[0002]

2. Description of the Related Art For example, it is known that a mountain fork that can be run on an off-road road or a bicycle that runs in an urban area is equipped with a suspension fork instead of a rigid fork for absorbing shocks during running. This type of front wheel suspension fork is generally classified into a fork type in which two suspensions are mounted instead of fork legs, and a head mounted type in which a suspension is arranged between a handle post and a fork stem. is there.

Fork type suspension forks are
Similar to the one used for motorcycles, two suspensions are arranged with the front wheel sandwiched between them, which causes a large number of parts and an increase in weight and price. On the other hand, in the head-mounted suspension fork, since one suspension may be arranged on the handle post, the number of parts can be reduced, the weight can be reduced, and the price can be suppressed. As this type of head-mounted suspension fork, a head shock (trademark) manufactured by Canondale, Inc. in the United States is known.

This head-mounted suspension fork has a fork portion for supporting a front wheel, a cylindrical first fork stem integrally formed with a handle post and rotatably supported by the head portion, and a first fork. A second fork stem whose tip side is arranged inside the stem and is fixed to the fork portion, an elastic member for urging the two fork stems in directions away from each other, a first fork stem and a second fork stem. And a connecting means composed of a needle bearing that is connected so as to be relatively movable in the axial direction and not relatively rotatable. The elastic members include those using urethane rubber and those using hydraulic / pneumatic cylinders. The needle bearing is arranged between the lower inner peripheral surface of the first fork stem and the upper outer peripheral surface of the second fork stem.

In this suspension fork, when an impact is applied to the front wheel, the second fork stem is guided by the needle bearing inside the first fork stem and moves upward against the biasing force of the elastic member to absorb the impact. To do. Further, when the handle is operated, the first fork stem rotates together with the handle, and the second fork stem is rotated through the needle bearing.
The fork stem rotates. As a result, the front wheels can be steered and bent in a desired direction.

[0006]

In the above-mentioned conventional suspension fork, since the connecting means for connecting the first fork stem and the second fork stem is composed of an expensive needle bearing, the cost of the connecting means becomes high, Suspension fork price increases. Therefore, such a suspension fork can be mounted only on a high-priced expensive mountain bike.

In order to reduce the drawbacks of this connecting means, it is conceivable to construct the connecting means with a key and a key hole for engaging the key. In this case, the price of the connecting means is reduced, and the price of the suspension fork is reduced. However, when the connecting means is composed of a key and a key hole, the first
In order to smoothly and relatively move the fork stem and the second fork stem in the axial direction, it is necessary to precisely control the dimensions of the key and the key hole. In addition, since the width of the key hole needs to be made larger than the width of the key to some extent, rattling easily occurs in the rotational direction at the connecting portion between the first fork stem and the second fork stem when the handle is operated.

An object of the present invention is to provide a suspension fork having a simple structure which can be mounted even on an inexpensive popular bicycle, and there is little need to control the dimensions of the key and the key hole constituting the connecting means, and the handle can be operated. An object of the present invention is to provide a suspension fork with less rattling in the rotational direction at the connecting portion between the first fork stem and the second fork stem during operation.

[0009]

A bicycle suspension fork according to a first aspect of the present invention is rotatably supported by a head portion of a bicycle, the fork portion, a tubular first fork stem, and a tubular body. A second fork stem, a biasing member, and a connecting means. The fork part supports the front wheel. The first fork stem is formed integrally with the handle post and is rotatably supported by the head portion. The second fork stem extends from the fork portion to the inside of the first fork stem and is supported relative to the inner peripheral portion of the first fork stem so as to be freely movable. The urging member is for urging the two fork stems in directions away from each other. The connecting means is a means including a key for connecting the first fork stem and the second fork stem so as to be relatively movable in the axial direction and not relatively rotatable, and a key hole for engaging with the key. The key is composed of a leaf spring and a plate-shaped member extending in the same direction as the leaf spring, and is engaged with the key hole by the leaf spring.
The leaf spring forming the key has a convex portion on the inner side of the second fork stem. The plate-shaped member that constitutes the key is
It has a concave portion or a hole at a position corresponding to the convex portion of the leaf spring. The keyhole has a width narrower than the free width of the key.

When a shock is applied to the wheel of a bicycle equipped with this suspension fork from the road surface, the second fork stem goes into the first fork stem against the biasing force of the biasing member and absorbs the shock. At this time, the key including the leaf spring is guided to the key hole, so that the second fork stem moves smoothly only in the axial direction of the first fork stem. On the other hand, when the handle attached to the handle post is operated, the first fork stem rotates with the operation, and the second fork stem non-rotatably connected to the first fork stem by the connecting means also rotates.

In this case, since the key includes the leaf spring, the clearance between the key and the key hole can be filled, so that rattling at the time of operating the handle is reduced. Further, by selecting the characteristics of the leaf spring, it is possible to adjust the sliding resistance when the suspension slides in the axial direction. Further, since the leaf spring substantially absorbs the dimensional error of the width of the key and the key hole, it becomes less necessary to precisely control the dimensions of the key and the key hole.

Further, since the leaf spring and the plate-shaped member forming the key are fitted in the convex portion and the concave portion or the convex portion and the hole, it is possible to prevent the plate-shaped member from falling out of the key. A bicycle suspension fork according to claim 2 is the bicycle suspension fork according to claim 1.
In the fork described in the above paragraph, the key hole is formed in the circumferential surface of the first fork stem along the axial direction, and the leaf spring constituting the key penetrates the second fork stem along the diameter thereof. At the same time, it has a bent portion projecting from the outer peripheral surface and bent outwardly at both ends.

A bicycle suspension fork according to claim 3 is the fork according to claim 1 or 2, wherein
The leaf spring that constitutes the key has a pawl that engages with the inner peripheral surface of the second fork stem. As a result, the key does not fall out of the second fork stem, and its position with respect to the fork stem is maintained. A bicycle suspension fork according to a fourth aspect is the fork according to the first to third aspects, wherein a pair of the leaf springs is provided.
The plate member is arranged so as to be sandwiched by a pair of plate springs.

The bicycle according to claim 5 is a bicycle according to claims 1 to 4.
The bicycle suspension fork described in any one of 1 to 3 is attached to the head portion of the frame body. This suspension fork has less rattling when the handle is operated,
In addition, the suspension slides smoothly due to an appropriate sliding resistance generated by adjusting the characteristics of the leaf spring.

[0015]

FIG. 1 shows a bicycle 1 equipped with a suspension fork according to an embodiment of the present invention. The bicycle 1 includes a frame 2 including a suspension fork 10, a steering unit 3 including a handle 11 fixed to an upper end of the suspension fork 10, a drive unit 4 arranged from a central portion to a rear portion of the frame 2, and a frame 2 of the frame 2. A traveling unit 5 including front and rear wheels 12 and 13 arranged at the front and rear, and a front and rear brake 1 for braking the front and rear wheels 12 and 13.
And a braking unit 6 including 4 and 15.

The frame 2 is a suspension fork 1
0, a main frame 20, a head portion 21, a back fork 22, and a seat support portion 23 are mainly provided. The front portion of the main frame 20 is bent and extends upward, and a head portion 21 is formed at the tip thereof. The head portion 21 is obliquely arranged along the rotation axis X whose upper portion is slightly inclined rearward.

The head portion 21 is the suspension fork 1
0 is rotatably supported around the rotation axis X. Head part 2
As shown in an enlarged scale in FIG. 2, 1 is a head pipe 31 that is welded to the front portion of the main frame 20, and a suspension fork 10 that is arranged vertically with the head pipe 31 interposed therebetween to rotate the suspension fork 10 around the rotation axis X. It has upper and lower bearing portions 32 and 33 that support it so as to be freely movable. As shown in FIG. 3, the suspension fork 10 includes an inverted U-shaped fork portion 40, a first fork stem 41 rotatably supported by the head portion 21, and an axial direction inside the first fork stem 41. Second fork stem 42 movably arranged
A coil spring 43, which is a biasing member disposed inside the first fork stem 41, and a load adjusting bolt 44, which is a hexagon socket head cap bolt for adjusting the initial load of the coil spring 43 to adjust the hardness of the suspension. A connecting portion 45 for connecting the first and second fork stems 41, 42 so as to be relatively movable in the axial direction and non-rotatably, and a lower end bumper 46 for softening the impact on the extension side (lower end) of the suspension fork 10. Have

The fork portion 40 supports the front wheel 12 at its lower end and, in the middle, a cantilever type front brake 14
Rotatably supported. The first fork stem 41 is a tubular member integrally formed with a normal handle post to which the handle 11 is fixed. First fork stem 41
Has a first pipe part 55 and a second pipe part 56 fitted to the outer periphery of the first pipe part so as to be arranged inside the head part 21.

The second fork stem 42 includes the fork portion 4
The base end is fixed to the upper end of 0 and extends upward from there to the inside of the first fork stem 41. The second fork stem 42 includes a tubular pipe portion 42a and a pipe portion 42a.
Has a ring-shaped spring receiving portion 42b that closes the upper end of the. The outer diameter of the pipe portion 42a is equal to the first fork stem 41.
The size is slidable on the inner peripheral surface of the first pipe portion 55.

The coil spring 43 includes the first fork stem 4
1 is a biasing member for biasing the first and second fork stems 42 in a direction in which they are separated from each other, and a spring bearing portion 42b at the upper end of the second fork stem 42 and a spring bearing plate disposed at the lower ends of the load adjusting bolts 44. It is arranged in a compressed state with 65. The initial load of the coil spring 43 is the load adjusting bolt 4
By changing the screwing amount of No. 4 and changing the initial length, it can be freely adjusted within a predetermined range.

The lower part of the first fork stem 41 is shown in FIG.
As shown in FIG. 5, an elliptical slit groove 52 that serves as a key hole of the connecting portion 45 is formed along the axial direction. The width of the slit groove 52 is slightly narrower than the width of the detent key 51 including the leaf springs forming the connecting portion 45 in the free state and slightly larger than the width of the compressed state. At the intermediate portion of the pipe portion 42a of the second fork stem 42, the rotation preventing key 5 of the connecting portion 45 is provided.
1 penetrates the outer peripheral surface. The rotation stop key 51 is shown in FIG.
As shown in, the pipe portion 42a is arranged on the diameter thereof, and both ends of the pipe portion 42a project outward so as to be flush with the outer peripheral surface of the first fork stem 41.

As shown in FIG. 5, the detent key 51 is composed of a pair of leaf springs 81 and a plate-shaped member 82. The pair of leaf springs 81 are arranged so as to sandwich the plate-shaped member 82. ing. The leaf spring 81 has a convex portion 81a on the inner side of the inner peripheral surface of the pipe portion 42a, and further has a bent portion 81b bent outward to a protruding portion from the outer peripheral surface of the pipe portion 42a, It has claws 81c that engage with the inner peripheral surface of the pipe portion 42a at both ends.

The plate member 82 has a hole 82a at a position corresponding to the convex portion of the plate spring 81. By fitting the convex portion 81a of the leaf spring 81 into the hole 82a, it is possible to prevent the plate-shaped member 82 from coming off. In addition, the leaf spring 81
The bent portion 81b can fill the gap between the width of the slit groove 52 and the compressed width of the detent key 51. As a result, the slit groove 52 and the rotation stopping key 5
The need for precise dimensional control of the plate thickness of 1 is reduced, and the cost is reduced.

Further, the claw 81c of the leaf spring 81 can prevent the detent key 51 from falling off the pipe portion 42a. Pipe part 42 of the second fork stem 42
A stopper 62 made of urethane rubber, which constitutes the lower bumper 46, is attached to the inside of the upper end of a. Further, as shown in FIG. 2, an oval escape hole 63 for inserting the stop pin 61 is formed along the axial direction on the upper peripheral surface of the pipe portion 42a. This stop pin 61,
By the stopper 62 and the escape hole 63, the lower end bumper 46
Is configured. The stop pin 61 is arranged so that the detent key 51 abuts the stopper 62 at a position slightly before the lower end of the slit groove 52.

Next, the shock absorbing operation of the suspension fork 10 of the above embodiment will be described. When the bicycle rides on a curb or a step on the sidewalk while traveling on the road surface and an upward impact load is applied to the front wheels 12, the impact force is transmitted to the second fork stem 42 via the fork portion 40. Then, in the second fork stem 42, the detent key 51 is guided by the slit groove 52, moves upward in the first fork stem 41 against the biasing force of the coil spring 43, and compresses the coil spring 43. As a result, the second fork stem 4
The shock transmitted to 2 is absorbed by the coil spring 43. When the shock is absorbed, no force acts on the coil spring 43.
Move downward. Then, before the rotation preventing key 51 reaches the lower end of the slit groove 52, the stop pin 61 is
The peripheral surface of the stopper contacts the stopper 62, the stopper 62 is dented, and the shock is absorbed. As a result, the downward movement of the second fork stem 42 is restricted. For this reason,
It becomes difficult for the rotation preventing key 51 to come into contact with the lower end of the slit groove 52, and the hammering noise and the impact noise between the metals generated at the time of contacting are hardly generated.

When these suspensions slide, the detent key 51 and the slit groove 52 are engaged by the leaf spring 81 of the detent key 51, so that a sliding resistance is generated. This sliding resistance can be adjusted by selecting the characteristics of the leaf spring. With this sliding resistance,
The suspension slides smoothly. Further, when the handle attached to the handle post is operated, the first fork stem 41 rotates in accordance with the operation, and the second fork stem 42 non-rotatably connected to the first fork stem 41 by the connecting portion 45 also rotates. To do. Here, since the detent key 51 and the slit groove 52 are engaged with each other by the leaf spring 81 of the detent key 51 of the connecting portion 45, the clearance between the key 51 and the slit groove 52 can be filled, and the handle is operated. Rattling is reduced.

[0027]

In the bicycle suspension fork according to the present invention, since the key forming the connecting means includes the leaf spring, there is almost no clearance between the key and the key hole, and the rotation at the connecting portion when the handle is operated. Rattling in the direction is reduced. Further, since the leaf spring substantially absorbs the dimensional error of the width of the key and the key hole, it becomes less necessary to precisely control the dimensions of the key and the key hole. Further, when the suspension slides, the leaf springs forming the keys engage with the key holes to generate sliding resistance, so that the sliding becomes smooth. By selecting the characteristics of the leaf spring, the sliding resistance during axial sliding of the suspension can be adjusted.

[Brief description of drawings]

FIG. 1 is a partial side sectional view of a bicycle adopting an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a head portion.

FIG. 3 is a vertical sectional view of a suspension fork.

FIG. 4 is a cross-sectional view of a connecting portion between a first fork stem and a second fork stem that are connected by a key.

FIG. 5 is a sectional view of the key in a free state.

[Explanation of symbols]

 1 Bicycle 10 Suspension Fork 12 Front Wheel 21 Head Part 40 Fork Part 41 First Fork Stem 42 Second Fork Stem 43 Coil Spring 45 Connection Part 51 Lock Key 52 Slit Groove 81 Leaf Spring 82 Plate Member

Claims (5)

[Claims] 1. A bicycle suspension fork rotatably supported by a head portion of a bicycle, the fork portion for supporting a front wheel and a handle post being integrally formed, and rotatably supported by the head portion. A tubular first fork stem, and a tubular second fork stem extending from the fork portion to the inside of the first fork stem and movably supported on an inner peripheral portion of the first fork stem. A biasing member for biasing the two fork stems away from each other, a key including a leaf spring, and a key hole having a width narrower than a width of the key in a free state and engaging with the key. And a connecting means for connecting the first fork stem and the second fork stem so as to be relatively movable in the axial direction and non-rotatable relative to each other. A leaf spring having both ends protruding from the outer peripheral surface of the second fork stem and penetrating through the stem along its diameter, and having a convex portion provided on the inner peripheral portion of the second fork stem, and in the same direction as the leaf spring. A bicycle suspension fork, comprising: a plate-shaped member that extends and has a recess or a hole provided at a position corresponding to the protrusion of the plate spring. 2. The key hole is formed along an axial direction on a peripheral surface of the first fork stem, and a leaf spring constituting the key penetrates the second fork stem along a diameter thereof. The bicycle suspension fork according to claim 1, wherein the suspension fork according to claim 1 has bent portions that protrude from the outer peripheral surface and are bent outward. 3. The bicycle suspension fork according to claim 1 or 2, wherein the leaf spring has a claw that engages with an inner peripheral surface of the second fork stem. 4. The bicycle suspension fork according to claim 1, wherein a pair of the leaf springs is provided, and the plate-shaped member is arranged so as to be sandwiched by the pair of leaf springs. 5. A bicycle in which the bicycle suspension fork according to any one of claims 1 to 4 is mounted on a head portion of a frame body.