JPH0334502Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an adjuster cam support device for a drum brake, which is frequently used as a braking means for automobiles.

<Prior Art> In order to adjust the shoe clearance, an adjuster cam is often pivotally attached to a brake spider that supports the brake shoe.

By the way, since such an adjuster cam is located under the spring, it is easy for muddy water etc. to adhere to it.Furthermore, since the shoe clearance is adjusted infrequently by the adjuster cam, the shaft supporting surface of the shaft that supports the cam corrodes, causing damage to the brake spider. may become stuck, making it impossible to adjust the shoe clearance.

In order to eliminate such problems, in recent years, grease has been applied to the sliding surface (rotating surface) between the brake spider and the shaft, or
As seen in Japanese Patent Publication No. 2003-121016, some brakes are equipped with an O-ring to improve the sealing performance between the shaft and the brake spider.

<Problem that the invention attempts to solve> However, applying grease in this way,
Alternatively, even if a sealing structure using an O-ring or the like is adopted, it is not always possible to accurately prevent the adjuster cam from sticking because the grease or O-ring deteriorates due to muddy water.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a support device for an adjuster cam with excellent durability that can prevent the adjuster cam from sticking over a long period of time.

<Means for Solving the Problems> In order to achieve the above object, the present invention interposes between the brake spider and the adjuster cam a bush made of a rust-free material and having a length approximately equal to the thickness of the brake spider. There is. The end face of the bushing is sandwiched between a stepped portion formed on the shaft and having a diameter larger than the bushing and a washer inserted and held by the shaft and having a larger diameter than the bushing.

<Function> In the drum brake adjuster cam support device configured as described above, since a bush made of a rust-free material is interposed between the shaft of the adjuster cam and the brake spider, the adjuster cam and brake spider are Will not rust. In addition, since the bushing is sandwiched between the stepped part of the shaft and the washer inserted and held by the shaft, there is no need to provide a flange part on the bushing to prevent it from falling off, or there is no need to prevent the bushing from falling off. Since it can be protected by the stepped portion and washer, stable support can be achieved over a long period of time.

<Example> An example of the present invention will be described below in detail based on the accompanying drawings.

In the figure, a brake spider 2 supporting a brake shoe 1 that slides on the inner circumferential surface of a brake drum (not shown) is equipped with a wheel cylinder 3 for expanding and narrowing the brake shoe 1. 4 is a brake lining, 5 is a return spring, and 6 is an oil pipe.

On the other hand, the brake spider 2 has an adjuster cam 7 for adjusting the shoe clearance.
is attached to the shaft. When the adjuster cam 7 is attached to the brake spider 2, a bush 8 made of a rust-proof material such as phosphor bronze is interposed between the brake spider 2 and the shaft 9 of the adjuster cam 7. Butsuyu 8
Grease is applied to the sliding surface between the shaft 9 and the shaft 9.

Therefore, even if the shaft 9 becomes rusted due to muddy water etc. scattered from the road surface as the vehicle travels, at least the shaft 9 will not be stuck to the brake spider 2.

Incidentally, by forming an oil reservoir of an appropriate volume on the inner circumferential surface of the bush 8, that is, the sliding surface with the shaft 9, the grease can be stored for a long period of time. Furthermore, by providing the shaft 9 with a stepped portion 10 having a larger diameter than the bush 8 and inserting and holding a washer 11 in the shaft 9, a washer 11 having a larger diameter than the bush 8 is inserted and held in the shaft 9. Button 8 is inserted.
Therefore, there is no need to provide a flange or the like on the bush 8 to prevent it from falling off the brake spider 2, and even if it is formed into a simple cylindrical shape, it will not fall off from the brake spider 2. Furthermore, since the end face of the bush 8 can be protected by the covering action of the stepped portion 10 and the washer 11, there is a low possibility that the bush 8 will come into direct contact with muddy water that has entered from the outside, and abnormal wear of the bush 8 can be prevented. A stable supporting effect can be achieved over a long period of time.

<Effects of the invention> As explained above, according to the invention, even if the shaft becomes rusted due to adhesion of muddy water, at least the shaft will not be stuck to the brake spider, so the shoe clearance can be reduced. Even if the adjustment interval becomes long, the adjuster cam will not become stuck as in the conventional case. In addition, the indentation of the bushing can be used to retain grease (lubricating oil) for a long period of time, and since the bushing that does not deteriorate easily with the O-ring is used, rusting of the adjuster cam can be reliably avoided. can do. Furthermore, since the bushing is sandwiched between the stepped portion formed on the shaft of the adjuster cam and the washer inserted and held on the shaft, even if the bushing is formed into a simple cylindrical shape, it will not fall off from the brake spider. Moreover, since the end face of the bushing can be protected by the covering action of the step portion and the washer, a stable supporting action can be performed over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of a drum brake equipped with the present invention, and FIG. 2 is an enlarged sectional view of the main parts. 1...Brake shoe, 2...Brake spider, 7...Adjuster cam, 8...Button shoe, 9
...Shaft.

Claims (1)

[Scope of utility model registration request] In a brake drum in which an adjuster cam for adjusting shoe clearance is attached to a brake spider supporting the brake shoe, a length approximately equal to the thickness of the brake spider made of a rust-free material is provided between the brake spider and the shaft of the adjuster cam. A drum is characterized in that a bush is interposed therebetween, and the end face of the bush is sandwiched between a stepped portion formed on the shaft and having a diameter larger than the bush and a washer that is inserted and held by the shaft and has a diameter larger than the bush. Brake adjuster cam support device.