JPH02240419A - Back plate for drum brake - Google Patents

Abstract

PURPOSE:To reduce a braking noise while improving suppression of vibration, when a brake is applied, by connecting a reinforce plate to a back plate body by a connecting member interposed in an air gap in the vicinity of a supporting member. CONSTITUTION:Between a back plate body 2, welding and securing a reinforce plate 3, and its peripheral part, an air gap 0 is formed, and a shoe holding pin 4, supporting a brake shoe 5, is fixedly provided in the peripheral part of the reinforce plate 3. Further the back plate body 2 secures to its through hole 2a a nut member 10 screwing a bolt 11 forcing its point end part to come into press contact with a base end part 4b of the shoe holding pin 4. Accordingly, a braking noise can be reduced by suppressing vibration, generated at the time of braking, with quality possible to improve by simplified structure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a back plate for a drum brake.

(Prior Art) As a conventional drum brake back plate, there is one disclosed in, for example, Japanese Utility Model Application Publication No. 59-43735.This back plate has a reinforcing rain on a disc-shaped back plate main body. A force plate is fixed, a gap is formed between the back plate main body and the outer periphery of the reinforcement plate, and a shoe hold pin as a support member for supporting the web of the brake shoe is fixed to the reinforcement plate.

Therefore, both sides of the web of the brake shoe are supported by shoe hold pins fixed to the thick reinforcement plate, and there is no contact with the hack plate.
The structure eliminates brake noise caused by direct sliding with the thin back plate.

[Problem to be solved by the invention]

However, in such conventional drum brake back plates, the vibrations generated when the brake shoes slide against the brake drum during braking are transmitted to the reinforcement plate via the shoe hold pins, causing the brake shoes and the rain Not only does the force plate vibrate, but the outer periphery of the free end of the back plate body, which forms a gap with the reinforcement plate, is violently vibrated, producing unpleasant braking noise, resulting in poor quality as a brake device. This created a new problem: inferior performance.

In addition, in a drum brake in which the reinforcement plate is provided with a support member that supports the web of the brake shoe, and the brake shoe slides on the ledge surface of the back plate, the brake shoe slides on the brake drum during braking. Vibration caused by contact is transmitted directly to the back plate body, which tends to cause brake noise.
Poor quality as a brake device.

(Means for solving !Ii!ll!) This invention
This was made in view of such conventional technical problems, and its configuration is such that a reinforcing reinforcement plate is fixed to the back plate main body, and the back plate main body and the outer periphery of the reinforcement plate are connected to each other. In a back plate for a drum brake in which a gap is formed and a support member for supporting a web of a brake shoe is fixed to the reinforcement plate, a cough reinforcement plate and the back plate main body are installed in the gap near the support member. This is a back plate for a drum brake that has a connecting member interposed therebetween.

[Effect]

Therefore, during a braking operation in which the brake shoes slide into contact with the brake drum, the vibrations of the brake shoes are transmitted to the reinforcement plate either directly to the back plate main body or via a support member or the like, and vibrate the back plate main body.

However, since a connecting member that connects the reinforcement plate and the back plate body is interposed in the gap formed between the back plate body and the outer periphery of the reinforcement plate, the outer periphery of the back plate body It is difficult to form an orderly vibration mode, and as a result, the vibration of the back plate body is suppressed, and generation of unpleasant brake noise is effectively suppressed. Since the reinforcement plate and the brake shoe are connected by the support member, by arranging the connection member near the support member, a good vibration damping effect can be obtained for the brake shoe and the reinforcement plate.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment in which the present invention is applied to a back plate for a drum brake equipped with a shoe hold pin. In FIG. It is constructed by welding and fixing a thick reinforcement plate 3 for reinforcement to a thin back plate body 2 which is molded into a substantially disk shape, and between the outer periphery of the reinforcement plate 3 and the back plate body 2. A void ○ is formed in the space.

A shoe hold pin 4 that is a support member that supports the brake shoe 5 is provided on the outer periphery of the reinforcement plate 3.
will be permanently installed. The shoe hold pin 4 has a stepped portion 4a.
and the crushed base end 4b, the reinforcement plate 3
The tip 4C, which is fixed to the outer periphery of the brake shoe 5 and has a male thread, is inserted through a long hole 5b formed in the web 5a of the brake shoe 5, and a slotted nut 6 with a flange screwed onto the tip 4C is inserted. By positioning with the bin 7 and supporting the upper surface of the web 5a, the brake shoe 5 is
This suppresses the lifting of the surface. A pair of brake shoes 5 are arranged facing each other on the back plate l so as to be able to freely slide on the ledge surface 2b of the back plate main body 2, and the lining 5C faces the inner circumferential surface of the brake drum 8 that rotates together with the wheel, and its end A wheel cylinder 9, which is an expanding means, is interposed in the section.

Then, a bolt 11 serving as a connecting member is attached to a nut member 10 welded and fixed around the through hole 2a of the back plate main body 2.
are screwed together from the back side, and the tip of the bolt 11 is pressed into contact with the base end 4b of the shoe hold pin 4, so that the reinforcement plate 3 and the back It is connected to the plate main body 2. This bolt 11 can be provided with a locking mechanism.

Next, the operation of the first embodiment will be explained. According to the drum brake back plate having such a structure, when pressure fluid is supplied to the wheel cylinder 9 and the brake shoes 5 are expanded, the lining 5c comes into sliding contact with the brake drum 8 and braking force is obtained.

At this time, the brake shoe 5 slides on the ledge surface 2b, the shoe hold pin 4 moves within the elongated hole 5b of the web 5a and expands, and the slotted nut 6 prevents the web 5a from lifting up. Ru. If you release the brake,
The brake shoe 5 returns to its original position by the action of a return spring (not shown).

During this braking operation, the vibration of the brake shoe 5 is transmitted from the ledge surface 2b directly to the back plate main body 2 or via the wheel cylinder 9 or shoe hold pin 4 to the reinforcement plate 3, thereby exciting the back plate main body 2. . However, the outer peripheral part of the back plate main body 2 is connected to the thick reinforcement plate 3 by a pole 11 that presses against the base end 4b of the shoe hold pin 4 that is integrated with the reinforcement plate 3, so it is not neatly connected to the thick reinforcement plate 3. Therefore, the outer peripheral portion of the back plate main body 2 is damped, and generation of unpleasant brake noise is suppressed. In addition, the reinforcement plate 3 and the brake shoe 5 are connected to each other so that vibrations are transmitted by the shoe hold pin 4.
By press-contacting them, the vibration damping effect of the reinforcement plate 3 and the brake shoe 5 can be obtained simultaneously.

FIG. 2 shows a second embodiment in which the present invention is applied to a drum brake back plate equipped with a squareness holding pin, and the same parts as in FIG. . In this embodiment, a squareness holding pin 12, which is a support member that supports the brake shoe 5, is fixed to the reinforcing reinforcement plate 3. The squareness holding bottle 12 is in the shape of a bolt with a male thread, and is inserted through the through hole 2a of the back plate main body 2 and the through hole 3a on the outer periphery of the reinforcement plate 3, and is connected to the nut member 13 and the head 12a. It is fixed to the back plate main body 2 and has nut members 14 on both sides of the reinforcement plate 3.
．． 15 are screwed together and fixed to the reinforcement plate 3. Therefore, the lower portion 12b of the squareness holding bin 12 than the reinforcement plate 3 in the figure functions as a connecting member, and the reinforcement The upper portion 12c functions as a support member that connects the plate 3 and the back plate main body 2 and supports the brake shoe 5.

That is, the tip of the squareness holding pin 12 slidably contacts one side of the web 5a of the brake shoe 5, and maintains the squareness of the web 5a of the brake shoe 5. In addition, each of the socket members 13, 14 and 15 can be provided with a locking mechanism.

Next, the operation of the second embodiment will be explained. According to the drum brake back plate having such a structure, tilting of the brake shoe 5 during braking is suppressed by the squareness holding pin 12, and braking force can be obtained without causing the brake shoe 5 to locally contact the brake drum 8. At the same time, the outer peripheral part of the back plate main body 2 is attached to the thick reinforcement plate 3 by the lower part 12b of the squareness holding bin 12.
Since the structure is such that it is difficult to form an orderly vibration mode, the vibration of the outer circumference of the hack plate body 2 during braking operation is suppressed, and the generation of unpleasant brake noise is well suppressed. be done. Further, the reinforcement plate 3 and the brake shoe 5 are connected to each other by the upper portion 12c of the squareness holding pin 12 so that vibrations are transmitted, but the back plate main body 2 and the reinforcement plate 3 are held at a squareness. Lower part 1 of pin 12
2b, the vibration damping effect of the reinforcement plate 3 and the brake shoe 5 can be obtained simultaneously.

Table 1 shows the results of testing the back plate 1 of the second example using a dynamometer.

That is, the hack plate I and the conventional back plate P were attached to a dynamometer, a test was conducted while changing the temperature of the lining 5c, and the generated sound pressure of 1.5 Kl (z) was measured as noise.

Table 1 As can be seen from Table 1, the conventional back plate P has a temperature of 109°C in a wide temperature range of 60 to 150°C.
~118 dB(A) of noise was generated, but according to the back plate l shown in Figure 2, only 90 dB(A) of noise was generated at a temperature of 150°C, indicating that a good damping effect was obtained. It can be seen that In addition, the hack plate I shown in FIG. 2 had good noise evaluation based on sensation.

By the way, in the first embodiment, the tip of the connecting member Pol II is pressed against the base end 4b of the shoe hold pin 4, but the tip of the bolt 11 is connected to the shoe hole 1 pin 4. reinforcement plate 3 near the base end 4b of
If the connecting member is pressed into contact with the surface angle holding pin, substantially the same effect can be obtained regarding vibration damping of the hack plate main body 2, the reinforcement plate 3, or the brake shoe 5. 12, but the connecting member is formed separately from the surface angle holding pin 12, and the connecting member is placed near the surface angle holding pin 12, so that the reinforcement plate 3 and the hunk plate zero body 2 can be connected to each other. Even if they are connected, substantially the same effect of 1p can be obtained regarding the vibration damping described above. Furthermore, it goes without saying that the present invention can be similarly applied to a drum brake hack plate having a structure in which the Brasen Sony 5 is not in contact with the back plate main body 2 and is supported by a shoe hold bin 4 which is a supporting member. It is.

[Effects of the Invention] As can be understood from the above explanation, according to the present invention, the vibration generated when the brake shoe comes into sliding contact with the brake 1 ram during braking and is transmitted to the back plate etc. can be effectively suppressed. Since unpleasant brake noise due to vibration is significantly reduced, the simple structure has the practical effect of improving the quality of the brake device.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a main part of a drum brake back plate according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a main part of a drum brake back plate according to a second embodiment of the present invention. In the cross-sectional view, 1: Back plate 2: Hack plate body 3; Reinforce plate 4: Hold pin (supporting member), 5 Brake shoe, 5
a: web 8 brakes) ram 11: bolt (connecting member), 12: surface angle holding pin (supporting member and connecting member), O: gap. Agent Patent Attorney Mae 1) Hiroshi 1st figure 2nd figure

Claims (1)

[Claims] (1) A reinforcing reinforcement plate is fixed to the back plate body, a gap is formed between the back plate body and the outer periphery of the reinforcement plate, and the web of the brake shoe is supported on the reinforcement plate. A drum brake back plate having a support member fixed thereto, characterized in that a connecting member connecting the reinforcement plate and the back plate main body is interposed in the gap near the support member. back plate.