JP2596531Y2 - Bicycle hub brake - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for improving the effectiveness of a hub brake for a bicycle and performing a good braking operation.

[0002]

2. Description of the Related Art Conventionally, as a bicycle hub brake, as shown in FIG. 7, a brake drum 1 rotating integrally with a wheel hub, a brake shoe 2 pressed against the brake drum 1, and this brake shoe 2 A plurality of rollers 3 for pressing the brake shoes, a brake operation cam 4 for pressing the brake shoes 2 against the brake drum 1 by pressing the rollers 3, and the brake shoes 2, the rollers 3, and the brake operation. There is known a roller-type one equipped with a cam 4. That is, the cam 4 is rotated around the axle 7 in the direction of arrow a via the cam lever 5, and the roller 3 is pushed outward by the inclined surface 4 a of the cam 4 so that the brake shoe 2 is moved to the inner surface of the drum 1. It presses against each other to generate a braking force.

[0003]

In the above structure, the drum 1 rotates in the direction of the arrow c as the bicycle advances, and the direction of rotation of the cam 4 is opposite to that of the cam 4. For this reason, the direction of movement of the roller 3 due to the rotation component of the brake shoe 2 with the drum 1 due to the generation of the braking force is the direction in which the roller 3 climbs the inclined surface 4a of the cam 4, and the braking force changes even with a slight brake operation. There was a tendency that it was relatively large and that it was difficult to finely adjust the braking force. An object of the present invention is to improve braking operability by obtaining a braking force suitable for a braking operation, improving the usability of a hub brake having excellent braking efficiency in an actual use area.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a brake drum which rotates integrally with a wheel hub, a brake body which presses the brake drum, and an intermediate member which presses the brake body against the brake drum. A brake operating cam for pressing the intermediate member against the brake drum by pressing the intermediate member, and a brake hub for a bicycle having a braking member, an intermediate member, and a holding member for holding the brake operating cam. As the brake operation cam rotates in the rotation direction of the brake drum with respect to the intermediate member, the pressing force of the brake body against the brake drum increases, and the brake body moves against the brake operation cam. Inclined cam surface that reduces the pressing force of the brake body against the brake drum by rotating in the rotation direction of the brake drum A mounting portion for forming the holding member and mounting the holding member near the tip of the wheel fork is connected to the holding member, and the holding member is rotatably provided around the axis of the wheel hub to provide a reaction force during a brake operation. Is configured to be received by a wheel fork via a mounting portion, an elastic body is interposed between the holding member and the wheel fork, and the braking force is reduced by elastic deformation of the elastic body. It is characterized by the following. Further, the wheel hub may be a front wheel hub, and the wheel fork may be a front wheel fork.

[0005]

According to a first aspect of the present invention, the rotational operation direction of the cam is set to be the same as the rotational direction of the drum, and the holding member is attached to the wheel fork via an elastic body.
Referring to FIG. 7, the drum 1 is rotating in the direction of arrow b as a precondition,
Rotates in the direction of arrow a. Then, the roller 3 as an intermediate member is extruded in the outer diameter direction to press the brake shoe 2 against the inner surface of the drum 1, but the direction in which the brake shoe 2 tries to rotate with the drum 1, that is, the roller 3 moves The direction in which the movement is to be performed is a direction going down the inclined surface 4a of the cam 4, and a negative self-servo action occurs. This effect is further enhanced by the interposition of the elastic body.

In the prior art, the brake force was naturally increased even when the brake lever was slightly operated by slightly operating the brake lever, whereas in the present invention, the brake lever was slightly operated. In this case, only a braking force corresponding to the operation stroke is generated. In other words, the generated braking force for the input matches the operation feeling, and fine adjustment of the braking force is facilitated.

[0007]

[Effect of the Invention] As a result, it has been possible to provide a hub brake with improved ease of handling and usability in actual use conditions and further improved braking operability.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings when applied to a front wheel of a bicycle. FIG. 1 is a side view of a front wheel hub brake B, and FIG. 5 is a cross-sectional view thereof. Reference numeral 1 denotes a brake drum integrally formed with a wheel hub 16, 2 denotes a brake shoe (corresponding to a brake body),
Reference numeral 3 denotes a roller (corresponding to an intermediate member), 4 denotes a brake operation cam, and 5 denotes a cam lever, and a brake frame (corresponding to a holding member) 6 for holding the brake shoe 2, the roller 3, and the brake operation cam 4 is connected to a front axle 7 To fit into and
An arm portion (corresponding to an attachment portion) 6A is mounted on the fork 8 to prevent rotation, and receives a brake reaction force (torque). 1a is a grease pool, 24 is a ball, 2
5 is a ball push, and the brake frame 6 is a bush 2
6 is rotatably fitted to the outside.

As shown in FIGS. 4 and 6, there are six cylindrical rollers 3, and six operation cam surfaces 4a of the corresponding brake operation cams 4 are formed.
Are three rollers having a length straddling the two rollers 3 and 3 and are fitted in the outer circumferential grooves of these brake shoes 2.
A ring-shaped pressing spring 27 urges and presses in the inner diameter direction. A holder 9 for holding the six rollers 3 at equal intervals penetrates a pin 10 planted in one of the six holder portions 9a into an elongated hole 11 formed in the brake frame 6. And waterproof cap 1
A return spring 18 is applied to the protruding portion penetrating through 7.

The waterproof cap 1 is provided on the brake operation cam 4.
Cam lever 5 extending to the outside through the notch 7
The cam lever 5 is pressed and urged in the brake releasing direction by a return spring 23 provided between the waterproof cap 17 and the decorative cap 22 mounted on the outside thereof. . The distal end of the cam lever 5 is connected to an inner wire 21a of a brake cable 21 via a wire receiver 20, and the outer wire 21b is supported by a receiving portion 19 of a spring receiver 12 described later.

[0011] Explaining the braking action of the hub brake B,
When the inner wire 21a is pulled by gripping the front wheel brake lever (not shown), the brake operation cam 4 is moved via the cam lever 5 in the direction of arrow a in the same direction as the drum 1 rotating in the direction of arrow b as shown in FIG. By rotating the roller 3 on the inclined operation cam surface 4a, the brake shoe 2 is pushed out in the outer diameter direction and pressed against the drum 1 to generate a braking force. At this time, the holder 9
Slightly rotates, but by the action of the return spring 18,
When the brake is released, the cam lever 5 returns to the original position, and the cam lever 5 also returns to the original position by the action of the return spring 23. The direction of rotation of the brake operation cam 4 is the same as the direction of rotation of the drum 1 due to the advancing wheel, and the roller 3 causes the operation cam surface 4a to rotate along with the rotation of the brake shoe 2 with the drum 1 due to the generation of braking force. It will push in the downward direction, causing a negative self-servo effect. For this reason, the more the braking operation is performed, the stronger the negative self-servo action becomes, and the self-lock phenomenon is prevented from occurring mechanically.

In short, when the brake operation cam 4 rotates on the operation cam surface 4a relative to the roller 3 in the rotation direction of the drum 1, the pressing force of the brake shoe 2 against the drum 1 increases, and the brake shoe 2 The brake shoe 2 is formed on an inclined cam surface in which the pressing force of the brake shoe 2 against the drum 1 is reduced by rotating the drum 1 with respect to the operation cam 4 in the rotation direction.

As shown in FIGS. 1 to 4, an arm portion 6A for stopping rotation of the hub brake and a fork 8 are connected via an automatic braking force reduction device A. That is, an open-top box-shaped spring receiving body 12 is mounted on the back side of the fork 8, and an action portion 6a bent at the tip of the arm portion 6A is formed.
, An automatic braking force reduction mechanism A is provided with an elastic mechanism S interposed therebetween. The elastic mechanism S includes four large and small compression wound springs (corresponding to elastic bodies) 13, 13, 14, and 14,
Large springs 13 having a large diameter are vertically arranged in parallel.
Small springs 14 are arranged in the insides 3 and 13. The bifurcated guide member 15 is attached so as to pass through the center side space of the upper and lower small springs 14 and to extend between the action portion 6 a and the spring receiving body 12.

The operation of the braking force automatic lowering device A is such that when the hub brake B is actuated, the brake frame 6 as a support thereof tries to rotate in the same direction as the rotation direction of the front wheels, that is, in the direction of arrow b in FIG. The point is that the tensile force of the inner wire 21a is reduced by the compressive deformation of the elastic mechanism S. That is, as the braking force increases, the elastic mechanism S undergoes compressive deformation, and the rate of increase of the actually generated braking force becomes lower than before the elastic mechanism S undergoes compressive deformation. As a result, advantages such as prevention of wheel lock and stabilization of the vehicle body posture during braking are obtained.

[Alternative Embodiment] The roller 3 may have a hollow cylindrical shape or a spherical shape, and these are generically defined as an "intermediate member".
The hub brake may be applied as a braking device for the rear wheels, or may be directly fixed to the fork 8 without interposing the automatic braking force reduction mechanism A.

In the claims of the utility model registration, reference numerals are written for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

FIG. 1 is a side view of a front wheel hub brake.

FIG. 2 is a rear view of a front wheel hub brake.

FIG. 3 is a cross-sectional view of an automatic braking force reduction mechanism.

FIG. 4 is a side view of the hub brake with a decorative cap removed.

FIG. 5 is a sectional view of a hub brake.

FIG. 6 is a cross-sectional side view of a braking force generating portion of the hub brake.

FIG. 7 is an operation diagram of a braking force generating portion showing a braking operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake drum 2 Braking body 3 Intermediate member 4 Brake operation cam 4a Operation cam surface 6 Holding member 6a Attachment part 8 Wheel fork 13, 14 Elastic body

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B62L 1/00

Claims (2)

(57) [Scope of request for utility model registration] 1. A brake drum (1) that rotates integrally with a wheel hub (16), a brake (2) that presses against the brake drum (1), and the brake (2) is attached to the brake drum (1). An intermediate member (3) that is pressed against the brake member, and a brake operation cam (4) that presses the brake body (2) against the brake drum (1) by pressing the intermediate member (3). A bicycle hub brake having a body (2), the intermediate member (3), and a holding member (6) for holding the brake operation cam (4), wherein an operation cam surface of the brake operation cam (4). (4a)
The brake drum (1) when the brake operation cam (4) moves forward with respect to the intermediate member (3) when the bicycle advances.
When the brake body (2) rotates in the rotation direction, the pressure contact force of the brake body (2) against the brake drum (1) increases, and the brake body (2) moves against the brake operation cam (4).
The brake member (2) is formed on an inclined cam surface in which the pressing force of the brake body (2) against the brake drum (1) is reduced by rotating in the rotation direction of the brake drum (1) when the bicycle advances , and the holding member ( 6) near the tip of the wheel fork (8)
Connecting the mounting portion (6a) to the holding member (6).
And the holding member (6) is connected to a shaft of a wheel hub.
Rotationally installed around the core to reduce the reaction force during brake operation
The wheel fork (8) through the mounting portion (6a)
The holding member (6) and the vehicle
Elastic body (13), (14) between wheel fork (8)
And elastic deformation of the elastic bodies (13) and (14)
Therefore, a bicycle configured to reduce braking force
For hub brake. 2. A bicycle hub brake according to claim 2, wherein said wheel hub (16) is a front wheel hub, and said wheel fork (8) is a front wheel fork.