JPH03282026A - Drum type brake - Google Patents

Abstract

PURPOSE:To prevent vibration and to effectively prevent squeak without bad influence on brake performance with a simple constitution by attaching a brake lining to a brake shoe via a thin tabular damping material. CONSTITUTION:A thin tabular damping material 11 is fixed with rivets 12 to the outer periphery of the rim 6c of a brake shoe 6 made of steel and having a web 6d fixed to the rim 6c, and a brake lining 13 is jointed to the outer periphery of the damping material 11 with adhesive agent. Therefore, it is possible to damp vibration of the brake shoe 6 with simple constitution and to effectively prevent squeaking without bad influence on brake performance.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a drum type brake, and more particularly to a drum type brake that suppresses vibration of brake shoes during braking to prevent brake squeal.

BACKGROUND OF THE INVENTION A conventional braking device 1, as shown in FIG. 5, is manufactured by fixing a brake lining 3 to a rim 2a of a brake shoe 2 with a rivet 4, which is an example of a fastening member. By pressing the brake lining 3 against the inner peripheral surface of a brake drum (not shown), a wheel (not shown) is pressed.
It is configured to apply braking force to.

The brake lining 3 is usually made of asbestos, resin, metal, etc., as it is required to have a suitable coefficient of friction, be resistant to wear, and withstand the fading phenomenon caused by frictional heat. When pressed against the brake drum during braking, the brake lining 3 may generate minute vibrations together with the brake shoes 2 due to friction with the brake drum, resulting in so-called brake squeal phenomenon. To effectively prevent this brake squeal. has traditionally been considered extremely difficult.

One way to prevent this brake squeal phenomenon is to conduct vibration analysis experiments and increase the rigidity of parts that are presumed to be the cause of the squeal, such as the brake shoes 2. However, this solution is not always possible. This problem has not been solved theoretically and is largely a result of trial and error, so it is expected that more man-hours will be required to solve it. Another prevention method is to improve the friction characteristics by changing the material or composition of the brake lining 3, but the factors contributing to brake squeal are the friction coefficient and resistance required for the brake lining 3. It often conflicts with performance such as magical wear resistance,
It has been extremely difficult to improve brake squeal without deteriorating these performances.

Purpose The present invention has been made in order to eliminate the problems of the prior art described above, and its purpose is to reduce the vibration of the brake shoes by fixing the brake lining to the brake shoes via a damping material. The purpose of this invention is to attenuate brake shoe noise and thereby effectively prevent brake shoe squeal with a simple configuration.

Another objective is to make it possible to use materials with the highest performance required for brake linings without considering brake squeal, thereby improving brake performance without adversely affecting braking performance. The purpose is to prevent squealing.

Configuration In short, the present invention provides a drum type brake that applies braking force to a wheel by pressing a brake lining attached to a brake shoe against the inner peripheral surface of a brake drum, in which a thin plate-like damping material is attached to the brake shoe. The brake lining is attached to the brake shoe to prevent vibration of the brake shoe.

The present invention will be explained below based on embodiments shown in the drawings. As shown in FIG. 1, a drum type brake 5 according to the present invention has a pair of brake shoes 6 disposed facing each other, and one end 6a of each brake shoe 6 is fixed to a spider 7 (not shown). It is pivotally attached to the anchor pin 8 so as to be freely rotatable. The other end 6b is disposed opposite to the operating cam 9, and the operating cam is rotatably connected to the shaft 10, and the outer circumferential surface has a gradually increasing distance from the center of the shaft 10. For example, cam surfaces 9a formed in an involute curve shape are formed at two locations. The operating cam is configured to rotate around a shaft 10 by operating a brake pedal (not shown), thereby moving the other ends 6b of the brake shoes 6 that are in contact with the cam surface 9a in a direction in which they are separated from each other. .

Also, with reference to FIGS. 2 and 3, the brake shoe 6
is made of iron, for example, and has a T-shaped cross section with a web 6d fixed at right angles to a rim 6C formed in an arc shape. On the outer periphery of the rim 6C, a thin plate-like damping material 11 is arranged in the circumferential direction with a plurality of rivets 1, which are an example of a fastening member.
2, and a brake lining 13 is further bonded to the outer periphery of the damping material 11 with an adhesive or the like.

During braking, when the brake lining 13 is pressed against the inner peripheral surface of the brake drum, a large force acts on the damping material 11;
The thickness of the damping material 11 is determined according to the material of the damping material so that it does not buckle due to the force applied during braking, and is set to, for example, 2fi to 5m4.

Function The present invention is constructed as described above, and its function will be explained below. In FIG. 1, when the driver depresses the brake pedal (not shown), pressure oil with a pressure proportional to the amount of the brake pedal is pressed into the mask cylinder (not shown) is delivered to the operating cam via the wheel cylinder (not shown). 9 is rotated around an axis 10. The cam surface 9a of the operating cam 9 is rotated to the other end 6b of the brake shoe 6 according to the rotation.
The pair of brake shoes 6 are rotated clockwise and counterclockwise about their respective anchor pins 8, and the pair of brake shoes 6 are moved in the direction of separating them from each other.
The brake lining 13 is pressed against the inner peripheral surface of a brake drum (not shown) formed to surround the wheel, and braking force is applied to the wheel (not shown).

At this time, due to the friction between the brake drum and the brake lining 13, the brake drum and the brake lining 13 become high in temperature and vibrate, and the frequency of the vibration increases to the natural dynamic frequency (for example, 3000 Hz) of the brake shoe 6.
height until it matches.

Then, the brake shoe 6 vibrates violently at the frequency 1 and generates a sound at the frequency, resulting in what is called brake η.
Referring also to FIG. 3 and FIG. 3, the drum type brake 5 of the present invention has a damping material 11 arranged between the brake shoes 6 and the brake lining 3.
The vibration to the brake shoe 6 is weakened and
The vibration → is also damped by the energy absorption effect of the damping material 11, and brake squeal is significantly reduced.

Relationship G between the thickness of the damping material 11 and brake squeal: As a result of testing, as shown in FIG.
When the thickness of the brake is 5fi, the brake noise is approximately 1
A reduction of 5 dB was confirmed.

In addition, tests have confirmed that when the thickness of the damping material 11 is 2fi to 5m, it will buckle due to the force acting on the damping material during braking. It is possible to use materials with excellent performance, such as having the appropriate coefficient of friction required for braking without causing friction, being resistant to wear, and not causing fade, thereby eliminating brake squeal while maintaining high braking performance. can be prevented.

Effects In the present invention, as described above, the brake lining is fixed to the brake shoes via the damping material, so the vibration of the brake shoes can be damped, and as a result, the squeal of the brake shoes can be effectively suppressed with a simple configuration. The effect of preventing this can be obtained.

In addition, since it is possible to use materials with the highest performance originally required for brake linings without considering brake squeal, it is possible to prevent brake squeal without adversely affecting braking performance. be.

[Brief explanation of drawings]

1 to 4 relate to an embodiment of the present invention, in which FIG. 1 is a front view showing the entire drum type brake, FIG. 2 is a lateral end view taken along arrow nn in FIG. 1, and FIG. 4 is an explanatory diagram showing the relationship between the thickness of the damping material and brake squeal. FIG. 5 is an enlarged longitudinal sectional view of the main part of a conventional drum brake. It is.

Claims (1)

[Claims] In a drum type brake that applies braking force to a wheel by pressing a brake lining attached to a brake shoe against the inner peripheral surface of a brake drum, the brake lining is attached to the brake shoe via a thin plate-like damping material. A drum type brake, characterized in that the brake shoe is configured to prevent vibration.