JP2002048165A - Brake pad and method for preventing its generation - Google Patents

Abstract

(57) [Summary] [Problem] A brake pad capable of preventing generation of "unusual noise" at the time of braking without causing disadvantages such as an increase in manufacturing cost, a reduction in braking characteristics and durability, and a method of preventing the generation of the abnormal noise. I will provide a. According to a method for preventing abnormal noise, a lubricant block is disposed on a part of the surface of a friction material, and the abnormal noise at the time of braking is caused by the action of lubricant powder generated by friction with a surface to be braked. It is characterized by preventing occurrence. The brake pad, in which the friction material is attached to the base member, has a burial hole provided on the surface side of the friction material in a stipulated shape, and has a property that the inorganic lubricant is a main material and is worn together with the friction material. The lubrication material block is embedded. Graphite may be used as the inorganic lubricant. Further, it is preferable to use a rivet embedding hole for mounting a friction material as the embedding hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake pad and a method for preventing the generation of an unusual noise, in which the occurrence of unpleasant "unusual noise" at the time of braking can be eliminated by simple means.

[0002]

2. Description of the Related Art Various researches and developments have been made to prevent unpleasant abnormal noise, so-called "squeal", from occurring during braking operation of a brake pad of an automobile. For example, a method of forming a friction surface of a pad by appropriately combining a plurality of types of friction materials having different friction coefficients has been considered. Further, blending of an inorganic lubricant such as graphite with the friction material has also been performed.

[0003] Alternatively, as a prior art which is considered to be linked to a measure for preventing "abnormal noise" of a brake pad, a machine tool is mounted on a "graphite cast iron" base in which graphite pieces are mixed. A method of absorbing vibration energy of a machine into graphite pieces is known.

[0004]

However, when the friction surface is constructed by combining a plurality of types of friction materials, not only is the production of the friction material troublesome, but also due to differences in the degree of wear of each friction material, etc. It is highly possible that the braking characteristics of the pads change over time. Further, when an inorganic lubricant is blended into the friction material itself, even if "abnormal noise" hardly occurs, it has an adverse effect on essential braking characteristics, durability and the like.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a brake pad and a brake pad capable of preventing generation of "abnormal noise" at the time of braking without causing disadvantages such as an increase in manufacturing cost and a reduction in braking characteristics and durability. An object of the present invention is to provide a method for preventing abnormal noise.

[0006]

In order to achieve the above object, a method for preventing abnormal noise generation of a brake pad according to the present invention is provided by arranging a lubricant block on a part of the surface of a friction material and placing the block on a lubricant. It is characterized in that abnormal noise during braking is prevented by the action of the lubricant powder generated by friction with the braking surface. Then, it is preferable to use a molded body mainly composed of graphite for the lubricant block.

In a brake pad according to the present invention, a friction material is attached to a base member. In the brake pad, an inorganic lubricating material is used as a main material in a burial hole provided on the surface side of the friction material in a dot binding shape. It is characterized by burying a lubricating material block having the property of being worn together with the material. And it is good to use graphite as an inorganic lubricant. Alternatively, a rivet embedding hole provided in the friction material may be used as the embedding hole in order to attach the friction material to the base member.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The specific structure of the present invention will be described below with reference to the drawings. 1 to 3,
The brake pad A1 is shown as one embodiment of the present invention. The brake pad A1 is used for a disc brake of an automobile, and its basic structure is not particularly different from a well-known one.

That is, as shown in FIG. 2, a thick plate-like friction material 2 is adhered to the upper surface of a base-like base member 1 for attaching the brake pad A1 to its drive mechanism (not shown). And the like.

An embedding hole 4 for embedding the small cylindrical lubricating material block 3 shown in FIG.
Are formed at two positions near both ends of the friction material 2 in the longitudinal direction (the rotation direction of the braking surface).

The lubricating material block 3 of this embodiment is formed by molding a composition mainly composed of graphite having excellent lubricity and physical and chemical stability into a small cylindrical shape. The method of manufacturing the lubricant block 3 is, for example, the same as that for manufacturing a graphite electrode.

The outer peripheral surface of the lubricating material block 3 is preferably formed in a somewhat conical surface so that the lubricating material block 3 can be driven into the buried hole 4 in a retaining state by its wedge action. After driving the lubricating material block 3, as shown in FIG. 3 (a), the portion whose top is slightly protruded from the surface of the friction material 2 is ground to obtain a lubricating material as shown in FIG. 3 (b). Then, the surface is made flush with the surface of the friction material 2. Burial hole 4
It is preferable to apply an adhesive in advance.

Next, the operation of the brake pad A1 for preventing "abnormal noise" from occurring will be described. It has been sufficiently confirmed by a number of demonstration tests that the effect of preventing the generation of “unusual noise” can be remarkably obtained by embedding the lubricant block 3 on the friction surface of the friction material 2.

However, it is extremely difficult to theoretically analyze the effect of preventing the generation of "abnormal noise". Assuming this effect, it is as follows. Each time the friction material 2 of the brake pad A1 comes into pressure contact with the surface to be braked, it is slightly worn out. At the same time, the lubricant block 3 is also slightly worn away, and the finely divided graphite diffuses over the entire contact interface between the braking surface and the friction material 2.

The contact interface is not very smooth when viewed microscopically and is rather rough. Therefore, if braking is performed while the rotation speed of the braking surface is within a certain specific range, it is considered that a resonance phenomenon occurs due to the contact frictional force and "abnormal noise" occurs.

However, if graphite fine powder intervenes at the contact interface, it is presumed that even if the amount is very small, the excellent lubricating action prevents the occurrence of a resonance phenomenon. This guess seems to be almost appropriate when considered in conjunction with the vibration damping action of "graphite cast iron" mentioned in << Prior Art >>.

The graphite fine powder having a lubricating action is
There is a concern that the braking performance will be reduced by the presence of the braking interface. However, the amount of wear of the lubricating material block 3 is extremely small, and in reality, there is no adverse effect that causes a practical problem, but rather, a smoother braking feeling can be obtained.

Next, another embodiment of the brake pad of the present invention will be described with reference to FIGS. The brake pad A2 of this embodiment is for a drum brake mounted on a truck or a bus. The difference from the brake pad A1 is that the lubricant block 3
How to bury.

That is, the friction material 2 of the brake pad A2 is
As shown in FIG. 5, the base member 1 is
It is designed to be mounted on. Therefore, rivet embedding holes 6 are provided at a plurality of positions on the surface side of the friction material 2 as shown in FIG.

Therefore, in the case of the brake pad A2, the burying hole 4 of the lubricating block 3 does not need to be provided.
The rivet embedding hole 6 can be used as the embedding hole 4.

In this embodiment, as shown in FIG.
Of the rivet embedding holes 6 provided at two locations, two rivet embedding holes 6 located on one end side in the braking action direction of the friction material 2
Only the lubricating material block 3 is embedded. This is because if the total surface area of the lubricant block 3 with respect to the surface area of the friction material 2 is increased more than necessary, the essential braking performance may be adversely affected.

The function of the brake pad A2 is almost the same as that of the brake pad A1, and the description is omitted.

In the above embodiment, graphite is used as the material of the lubricating material block 3. However, an inorganic substance which is easily pulverized by contact frictional force with the surface to be braked and has good lubricating properties, for example, Well-known antimony sulfide, molybdenum sulfide, tungsten sulfide, etc. may be used alone or mixed as a main material or an auxiliary material. The shape of the lubricant block 3 is not limited to a cylindrical shape.

The use of the brake pad according to the present invention is not limited to the field of vehicles such as automobiles.

[0025]

As apparent from the above description, according to the brake pad and the method for preventing generation of abnormal noise according to the present invention, practically superior to the conventional products of the same type as listed below are obtained. The effect is obtained. (A) In the case of a drum brake, a sufficient "abnormal noise" preventing effect can be obtained only by driving a lubricating material block into the rivet embedding hole of the current brake pad. (B) In the case of a disc brake, a similar effect can be obtained only by driving a lubricating material block into each of the burial holes formed in a small number of portions of the friction material. (C) As for the friction material, a conventional product composed of a single material is sufficient,
Unlike the conventional products described at the beginning, there is no need for troublesome manufacturing such as combining a plurality of types of friction materials. (D) Since the lubricating material block is worn together with the friction material as its buried base, troublesome maintenance such as replacing only the lubricating material block at any time is not required. (E) The total area of the lubricant block is small compared to the surface area of the friction plate, and the amount of fine powder generated by wear of the lubricant is also small, so that the adverse effect on the braking performance can be ignored. (F) Generally speaking, it is possible to produce a brake pad which is more effective in preventing the generation of “unusual noise” and has a good braking feeling than conventional equivalent products at a lower cost.

[Brief description of the drawings]

FIG. 1 is a perspective view of a lubricant block according to an embodiment of the present invention.

FIG. 2 is a perspective view of the brake pad according to the first embodiment;

FIG. 3 is a longitudinal sectional view showing a state immediately after a lubricating material block is driven into an embedding hole and a state where a protruding portion of the lubricating material block has been ground.

FIG. 4 is a perspective view of a brake pad according to another embodiment of the present invention.

FIG. 5 is a partial vertical sectional view of FIG. 4;

[Explanation of symbols]

 A1, A2 Brake pad 1 Base member 2 Friction material 3 Lubricant block 4 Buried hole 5 Rivet 6 Buried hole

Claims (5)

[Claims] 1. A lubricating block is disposed on a part of the surface of a friction material to prevent abnormal noise during braking by the action of lubricating powder generated by friction with the surface to be braked. A method for preventing generation of abnormal noise in a brake pad. 2. The method as claimed in claim 1, wherein the lubricating block is made of a molded body mainly composed of graphite. 3. A base member having a friction material attached thereto, wherein a burial hole provided in a spot binding shape on the surface side of the friction material has a characteristic that it is made of an inorganic lubricant as a main material and is worn together with the friction material. Brake pad characterized by embedded lubricant block. 4. The brake pad according to claim 3, wherein the inorganic lubricant is graphite. 5. The brake pad according to claim 3, wherein a rivet embedding hole provided in the friction material is used as the embedding hole for attaching the friction material to the base member.