JPH0146733B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drum brake in which a brake arm is fitted to the outer end of a camshaft.

Drum brakes commonly used in motorcycles are designed to use an adjustment nut to adjust the engagement position between the brake rod and brake arm when the brake lining becomes worn. To adjust beyond
It becomes necessary to perform this at the fitting connection portion between the brake arm and the camshaft. That is, the brake arm is fitted to the outer end of the camshaft, and is therefore unfitted, separated, and fitted again after adjusting the mutual fitting angle.

However, since the above-mentioned mating connection part is exposed to the outside of the drum, it may be contaminated with rust or mud, or may be deformed, so it is necessary to forcefully pull out or forcefully push the brake arm when uncoupling and re-coupling. There is. However, the camshaft sometimes moves in the axial direction, making it difficult to perform separation and fitting operations. This work is not easy, especially if the camshaft moves recessed when refitting the brake arm.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a drum brake that prevents the camshaft from shifting when it is separated and refitted, thereby facilitating these operations.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In the figure, 1 indicates the body of a motorcycle, 2 indicates a rear wheel, and 3 indicates a drum brake provided on the rear wheel 2. As shown in FIGS. 2 and 3, the drum brake 3 is installed in a space formed between a brake drum 4 that also serves as a rear wheel hub and a support plate 5 that closes an opening on one side of the drum 4. , a pair of brake shoes 6,
6 (only one is shown). These brake shoes 6, 6 are expanded by a brake cam 7, as is well known, and each brake shoe 6, 6 is expanded by a brake cam 7.
The brake lining 8 stretched over the outer peripheral surface of the drum 4 is brought into pressure contact with the inner peripheral surface of the drum 4.
This frictional resistance is used to apply braking. Note that 9 indicates a tension coil spring for returning each brake shoe 6, 6, and 10 indicates a pivot pin of the brake shoe 6, 6.

The cam 7 is integrally or integrally connected to a camshaft 11, and the camshaft 11 is rotatably supported through the support plate 5. camshaft 1
One end of the support plate 5 projects outward from the support plate 5, and this projecting portion is provided with a connecting portion 12 having serrations carved therein. One end of a brake arm 13 is detachably attached to this connecting portion 12. The brake arm 13 is constructed by folding sheet metal, and has a fitting hole 1 that fits into the connecting portion 12.
It has 4. In addition, the brake arm 13 is
By tightening with bolts 15 and nuts 16, the fitting hole 14 is reduced in diameter and fixed to the connecting portion 12. The other end of the brake arm 13 is connected to a brake rod 17. The brake rod 17 is adapted to adjust the engagement position of the brake arm 13 by means of an adjustment nut 18. Note that 19 is a compression coil spring. The brake rod 17 is connected to a brake pedal 20.

A protrusion 21 serving as a tool hook is integrally formed on the outer end surface of the camshaft 11.
This protrusion 21 can be held with pliers (not shown), which will be described later.

According to the above configuration, the brake pedal 2
0, the brake rod 17 is pulled, the brake arm 13 is rotated, and therefore the brake cam 7 is rotated via the camshaft 11. Therefore, as described above, the brake shoes 6, 6 are expanded and the brake linings 8, 8 are pressed against the drum 4, so that braking is applied.

However, when the brake lining 8 wears out,
Normally, the connecting position of the brake arm 13 to the brake rod 17 is adjusted by operating the adjusting nut 18. However, when the adjustment amount of the adjustment nut 18 reaches its maximum limit, the brake arm 13 is removed from the camshaft 11 and adjustment is performed at this connection. In this case, loosen the bolt 15 and nut 16, pull out the brake arm 13,
The mounting angle is adjusted and the connecting portion 12 is fitted into the fitting hole 14 again, and the bolt 15 and nut 16 are tightened. However, if the connecting parts are rusted, caked with mud, or deformed, the camshaft 1 may be pulled out or pushed in with strong force.
1 causes positional deviation in the axial direction. In such a case, if the camshaft 11 is supported by pinching the protrusion 21 formed on the outer end surface of the camshaft 11 with a tool such as pliers, the brake arm 13 can be pulled out and
Since the camshaft 11 does not move during pushing, attachment and detachment can be easily performed. In this embodiment, if the protrusion 21 is made longer than the width l of the fitting part of the brake arm 13, then when the brake arm 13 is to be fitted to the camshaft 11, the protrusion 21 will always be on the outside of the brake arm 13. Since it protrudes, the protrusion 21 can be easily held with a tool such as pliers.

In the above embodiment, the protrusion 21 is formed integrally with the camshaft 11 on the outer end surface of the camshaft 11. However, the present invention is not limited to this. For example, as shown in the modified example of FIG. , camshaft 1
A screw hole 40 may be formed in the outer end surface of 1. When installing and removing the brake arm 13, a bolt 41 is screwed into this screw hole 40.
It can be used by pinching it with a tool such as pliers. In this case, it is convenient to screw a bolt used elsewhere, such as the bolt 15, into the screw hole 40, since there is no need to separately prepare the bolt 41. Of course, if the bolt 41 does not get in the way, the bolt 41 may be left screwed in as is.

As detailed above, in the present invention, a tool hooking portion is formed on the outer end surface of the camshaft, so when the brake arm is attached to and detached from the camshaft, this hooking portion is supported with a tool such as pliers. This prevents the camshaft from sliding in the axial direction, and thus allows the brake arm to be separated and refitted easily and quickly. Moreover, this structure has the advantage that it can be easily implemented because the hook portion is simply formed on the outer end surface of the camshaft.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention, and FIG. 1 is a partially cutaway side view of a motorcycle;
FIG. 2 is a side view of the main part, FIG. 3 is a sectional view, and FIG. 4 is a sectional view of the main part showing a modification. 3...Drum brake, 11...Camshaft, 12
...Connection part, 13...Brake arm, 14...
Fitting hole, 21...Protrusion (tool hook part), 40...
...Screw hole (tool hook).

Claims (1)

[Scope of Claims] 1. A drum brake in which a brake arm is removably fitted and connected to the outer end of a camshaft, characterized in that a hook portion for a tool is formed on the outer end surface of the camshaft. . 2. The drum brake according to claim 1, wherein the hook portion of the tool is a projection integrally provided on the camshaft.