JP2000220678A - Frictional member with slits and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frictional material capable of preventing a back plate from being corroded even when slits are formed up in order to prevent break squeal and one sided abrasion, and even when a porosity is increased as a counter-measure against break squeal. SOLUTION: In a frictional member 10 with slits wherein frictional material 12 is stuck on a back plate 11 so as to be formed with the slits 13 over the surface of the frictional material, a water proofing layer 14 is formed up at least in the bottom surface of each slit 13. The provision of the slits 13 over the frictional member thereby prevents break squeal and one sided abrasion. In addition, even moisture ingresses in the slits 13, the provision of the waterproofing layer 14 prevents mosture from penetrating therein, and effectively prevents the back plate from being corroded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction member used for a brake pad, a brake lining, a clutch facing and the like of an automobile, and more particularly, to a friction member which is in contact with a friction material of a back plate to which the friction material is attached. Prevention of rust.

[0002]

2. Description of the Related Art Friction members used for automobile brake pads, brake linings, clutch facings, etc. are friction materials formed by pressurizing and heating a powdery raw material obtained by mixing a fibrous material, a filler, a binder and the like. Usually, the friction material is bonded to a steel back plate to be formed. However, there is also a drum brake lining in which the friction material alone is not adhered to the back plate and becomes a component and is fixed to a metal substrate such as a brake shoe when used.

As the characteristics of the friction material, there are various friction characteristics represented by a friction coefficient. In addition, characteristics such as squealing, uneven wear, and face-to-face aggression when used as a brake are important.

[0004] Among these characteristics, brake squeal and
As a countermeasure against uneven wear, as shown in FIG. 3, it is known to form a slit 3 on the surface of the friction material 1 in a friction member in which the friction material 1 and the back plate 2 are integrally bonded. By forming such a slit 3, brake squeal and uneven wear can be prevented,
Further, there is an effect that a streak is hardly formed on the surface of the friction material.

On the other hand, it is known that when the porosity of the friction material is 10% or more, especially 15% or more, brake squeal is greatly reduced. In recent friction materials, the porosity is about 10% to 30%. It has come to be set.

[0006]

However, according to the study of the present inventor, the following facts have been found. FIG. 4 is a diagram showing the relationship between the porosity and the rust of the back plate. This involves making friction materials of various porosity, attaching them to the same steel back plate, and after the same period of time under the same conditions, peeling the friction material from the back plate and removing the rust on the back plate. Measure the area of
The value obtained by dividing by the bonded area to obtain% is plotted on the figure. The porosity is plotted on the horizontal axis of the diagram, and the percentage of the area where rust is generated is displayed on the vertical axis.

[0007] From the above diagram, it was found that when the porosity was increased, rust was easily generated. Specifically, when the porosity is about 7%, the rust rate is 50%, when the porosity is about 10%, the rust rate is about 60%, and when the porosity is about 15%, the rust rate is about 80%.
Has also reached. This is presumably because the friction material having a high porosity easily penetrates moisture and easily reaches the surface of the back plate. When rust is generated, the bonding force between the back plate and the friction material is reduced, and the friction material is easily peeled. Also, if a slit is formed in the friction material,
It is believed that because the distance between the bottom of the slit and the back plate is short, water is more likely to penetrate, and the portion of the back plate facing the slit is particularly susceptible to rust.

That is, countermeasures for suppressing brake squeal (making slits or increasing porosity)
It was found that this was not compatible with measures to prevent rust on the back plate.

Although such a thing may be considered unrelated to a friction member composed of a friction material alone without a back plate, such as a lining of a drum brake,
Since such a lining is used in a state of being stuck and fixed to a metal plate such as a brake shoe, rust is generated on the brake shoe or the like instead of the back plate, and it can be said that the same problem occurs.

The present invention has been conceived in view of the above facts. Even when a slit is formed to prevent brake squeal or uneven wear, or when the porosity is increased to prevent brake squeal, the back plate It is an object of the present invention to provide a friction material that can prevent rust from being generated on the like.

[0011]

In order to achieve the above object, the present invention provides a friction member having a slit formed on a surface of a friction material, wherein a waterproof layer is formed on at least a bottom surface of the slit. It is characterized by.

A structure in which the friction material is attached to a back plate, a structure in which a waterproof layer is formed on the entire surface of the slit, a structure in which the waterproof layer is a coating film, or a structure in which the friction material has a porosity It can be configured to be 7% or more.

Further, according to the method of manufacturing a friction member of the present invention, in the method of manufacturing a friction member having a slit in which a slit is formed on a surface of a friction material, after forming the slit, a waterproof layer is formed on at least a bottom surface of the slit. It is characterized by doing.

The friction material may be attached to a back plate, or a paint may be sprayed on the slit, and the paint adhered to the surface of the friction material after drying may be polished and removed.

[0015]

Embodiments of the present invention will be described below. FIG. 1 shows a first example of a friction member with a slit according to the present invention.
FIG. 4 is an enlarged cross-sectional view of a slit portion in the embodiment. The friction member 10 is manufactured in the same manner as the conventional one, but the method of manufacturing the friction member 10 is not particularly limited. For example, a back plate is placed on the bottom of a mold of a press device (not shown), a powdery friction material material is put in the mold, and the material is pressed and heated by a press machine. A method of forming the attached friction member may be used. Alternatively, a friction member may be formed by forming only a friction material portion from a powdery material by pressurizing and heating.
After that, the U-shaped slit 13 is excavated with a grindstone cutter or the like.

Thus, the conventional friction member with a slit is completed. The friction member of the present invention is the same as the conventional one up to now, but thereafter, the waterproof layer 14
Is characterized by the fact that This waterproof layer 14
Any material such as a synthetic resin film may be used as long as it is waterproof. This embodiment is formed by a coating film coated with a paint. Usually, since the width W of the slit 12 is narrow, it is not easy to form such a coating film. However, it can be formed, for example, by applying using a thin brush.

As the type of paint, water-based, oil-based, high solid, photocurable, powder (electrodeposition) paint and the like can be used.
Of these, oil properties are advantageous in terms of heat resistance and weather resistance, but water-based and powder coatings are desirable in terms of environmental friendliness.

The raw materials of the paint include acrylic, polyester, epoxy, polyurethane, urea, phenol,
Alkyd, fluorine, polyacrylsiloxane, polyimide, polyparaxylene, silicone resin and the like can be used. In particular, acrylic, polyester, epoxy and the like are preferable in terms of corrosion resistance, heat resistance, and price, and acrylic paint is particularly preferable.

However, ordinary paints, whether oily or water-based, are waterproof as long as they are dried, so that they are paints, and are not particularly limited. What is necessary is just to select from the above-mentioned economy and heat resistance.

The friction member 10 of this embodiment has a slit 13
Is formed, the same effect as in the related art can be obtained in preventing brake squeal and uneven wear. In addition, since the waterproof layer 14 is formed at the bottom of the slit 13 where water is most likely to penetrate, even if water enters the slit 13, it cannot easily penetrate into the back plate 11. 11 can be effectively prevented.

FIG. 2 shows a second embodiment of the present invention. In the first embodiment, the waterproof layer 14 is formed only on the bottom surface of the slit 13. However, after a long period of time, water enters from the side surface of the slit 13 and reaches the back plate 11 to generate rust. Is also conceivable. So, this embodiment
The waterproof layer is formed not only on the bottom surface of the slit 13 but also on the entire surface including both side surfaces.

As shown in FIG. 2A, after the slit 13 is formed, a waterproof layer 15 is formed thereon by spraying or the like. Because of the spray coating, the paint scatters over a wide area, and the waterproof layer 15 is also formed on the surface of the friction material 12 on both sides of the slit 13 as shown by 15a. If the surface of the friction material 12 has the coating film 15a as described above, the friction coefficient of this portion decreases, and problems such as deterioration of the braking effect and increase in slip of the clutch occur. Therefore, in the second embodiment, after forming the waterproof layer 15, the slit 1
The portions of the waterproof layer 15a on both sides of No. 3 are removed by shaving off with an abrasive such as a grindstone or paper, and as shown in FIG. 2 (b). In the second embodiment, spray coating can be adopted.
Although it is necessary to peel off the portion 15a later, the waterproof layer 15 can be formed efficiently.

Alternatively, if easy-to-peel papers are attached to the portion 15a in FIG. 2 and the papers are peeled off after spray coating, there is no need to remove them with an abrasive.

In the second embodiment, the waterproof layer 15 is formed not only on the bottom surface of the slit 13 but also on the entire surface of the slit including both side surfaces.
Is formed, so that the back plate 11
It is possible to more reliably prevent water from penetrating into the water than in the first embodiment.

Although the second embodiment employs spray coating, it is also possible to apply a brush to form a waterproof layer 15 as shown in FIG. 2B from the beginning. In both the first embodiment and the second embodiment, the effect is particularly large when the porosity of the friction material 12 is 7% or more, and more particularly when the porosity is 10% or more. .

[0026]

As described above, the friction member with a slit according to the present invention has a structure in which the waterproof layer is formed on at least the bottom surface of the slit, so that water can effectively be prevented from entering the back plate or the like. Rust on the back plate and the like can be reduced and prevented. Therefore, both the conventional brake squeal measure and the rust prevention measure can be performed without contradiction.

When the waterproof layer is formed on the entire surface of the slit, it is possible to more reliably prevent water from entering the back plate and the like, and to prevent rust on the back plate and the like.

If the waterproof layer is a coating film, there is no need to use a special material. When the friction material has a porosity of 7% or more, brake squeal can be further reduced, which is effective.

[Brief description of the drawings]

FIG. 1 is a view of a friction member with a slit according to a first embodiment of the present invention, and is an enlarged sectional view of a portion of the slit.

FIG. 2 is a view of a friction member with a slit according to a second embodiment of the present invention, and is an enlarged sectional view of a portion of the slit.

FIG. 3 is a perspective view of a conventional friction member with a slit.

FIG. 4 is a diagram showing a relationship between porosity and rust of a friction material.

[Explanation of symbols]

 Reference Signs List 10 friction member 11 back plate 12 friction material 13 slit 14, 15 waterproof layer

Claims (6)

[Claims] 1. A slit-type friction member having a slit formed on a surface of a friction material, wherein a waterproof layer is formed on at least a bottom surface of the slit. 2. The friction member with a slit according to claim 1, wherein the waterproof layer is formed on the entire surface of the slit. 3. The friction member with a slit according to claim 1, wherein the waterproof layer is a coating film. 4. The friction member with a slit according to claim 1, wherein the friction material has a porosity of 7% or more. 5. A method of manufacturing a friction member with a slit, wherein a slit is formed on a surface of the friction material, wherein the slit is formed, and then a waterproof layer is formed on at least a bottom surface of the slit. Manufacturing method. 6. The method of manufacturing a friction member with a slit according to claim 5, wherein a paint is spray-coated on the slit, and after drying, the paint adhered to the surface of the friction material is removed by polishing.