JP2967217B2 - Non-asbestos friction material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-asbestos-based friction material used as a disk pad for vehicles such as automobiles, brake linings, clutch facings, and the like. Medium used under load
The present invention relates to a non-asbestos-based friction material suitable as a disk pad or the like for a large vehicle.

[0002]

2. Description of the Related Art As is well known, a brake for a vehicle such as an automobile includes a drum brake which presses a brake against an inner surface of a brake drum to perform braking. There are two types of disc brakes, in which a brake pad is pressed against the side surface of a disk-shaped rotor to brake the disc.

[0003] In comparison with the drum brake, the above-mentioned disk brake allows heat to escape easily due to its structure.
Although there is an advantage that uniform braking can be easily obtained, a drum brake using a large brake is superior to a disk brake in terms of abrasion resistance. Therefore, when a disk brake is mounted on a medium-sized vehicle or a large vehicle and a brake pad made of a conventional general friction material is used for the disk brake, wear of the brake pad is severe, and It is said that the surface of the brake pad is cracked and cannot withstand long-term use. This is the reason why drum brakes have been generally used for medium and large vehicles and disk brakes have been used for small vehicles.

[0004] On the other hand, typical friction materials capable of withstanding high loads include C / C composites and sintered metals, and brake pads using these friction materials are used for medium-sized vehicles and large vehicles. Although it is conceivable that the disc brakes are formed, the C / C composite is excellent in braking performance at high speed, but has a disadvantage that the friction coefficient is low and the wear is large at low speed. On the other hand, one of the sintered metals has a problem that not only an unpleasant sound called squeal is easily generated, but also it is heavy in itself, and easily fired when the friction material becomes high temperature by braking.

[0005] The use of a mixture of hard ceramic fibers and ceramic powder with the friction material improves the wear resistance of the friction material itself. As a result, the striations (scoring) of the partner material such as the rotor become severe.

[0006] However, as described above, the disk
Compared with the drum brake, the key has the advantage that heat is easily released due to its structure, and it is easy to obtain uniform braking. Therefore, the friction that enables the mounting of the disk brake on medium and large vehicles The development of lumber was eagerly awaited.

The present invention is based on the background of the prior art described above, and has excellent wear resistance and stable performance not only under a low load but also under a high load such as when used in a medium or large vehicle. The main object of the present invention is to provide a non-asbestos-based friction material which exhibits a friction performance and can provide a brake pad for a disk brake or the like which has less face-to-face damage.

[0008]

In order to achieve the above object, the present invention employs a construction in which a reinforcing fiber other than asbestos and a binder and barium sulfate are filled with a thermosetting resin such as phenol resin. Non-asbestos-based friction material
It is characterized in that at least a part of the filler contains electrofused magnesia.

In the above configuration, the average particle size of the electrofused magnesia may be, for example, in the range of about 0.05 to about 1.0 mm, and the content of the electrofused magnesia may be, for example, friction. About 0.5 to the total amount of material
A range of about 20% by volume can be mentioned.

Hereinafter, the present invention will be described in detail.

The reinforcing fibers other than asbestos used in the present invention include, for example, organic fibers such as aramid fibers, acrylic fibers, phenol fibers, PVA fibers, and cellulose fibers; glass fibers, ceramic fibers, and carbon fibers. Inorganic fibers such as fibers, and a mixture containing one or more fibers of metal fibers such as steel fibers, copper fibers, and bronze fibers are used. These are used in conventional friction materials. It is the same as what was.

As the binder, for example, a thermosetting resin such as a phenol resin is used. As the filler, for example, barium sulfate, cash dust, calcium carbonate, etc. are used. Are also commonly used in ordinary friction materials.

Thus, the present invention is characterized in that at least a part of the filler contains electrofused magnesia.

The electrofused magnesia used in the present invention is obtained by arc-melting magnesium oxide having only a fine crystal form and then solidifying it to sufficiently develop crystals. Since this electrofused magnesia is obtained as a lump having advanced crystallization, in the present invention, it is pulverized, sieved, and adjusted to have an average particle diameter of about 0.05 to about 1.0 mm. Preferably, it is used.

Incidentally, the average particle size of the electrofused magnesia is about 0.3.
When the thickness is less than 05 mm, the electrofused magnesia is easily detached from the friction material, and the wear of the friction material is increased. On the contrary, the average particle diameter of the electrofused magnesia is about 1.
When it is 0 mm or more, the face-to-face aggression is deteriorated.

The content of electrofused magnesia is preferably about 0.5 to about 20% by volume based on the total amount of the friction material, and when the content of electrofused magnesia is about 0.5% by volume or less. Is not effective, and when the content of electrofused magnesia is about 20% by volume or more, the face-to-face aggressiveness increases,
The coefficient of friction becomes too high, which is not preferable.

The friction material of the present invention having the above structure can be formed into a friction material molded product such as a disk pad for a vehicle by a well-known method, similarly to the conventional product. It exhibits excellent functions not only at low load but also under high load.

Next, the present invention will be described in more detail with reference to examples.

[0019]

Examples 1-4 As electrofused magnesia, an average particle size of 0.
3mm those of (Tateho Chemical Ltd. A0-40) and other components shown in Table 1, also in the proportions shown in Table 1, the mixer - were uniformly mixed using a pressure 400 kg / cm ^2, at room temperature 1
Pre-molding for 600 minutes, then pressure 600kg / c
m ^2, after performing the compression molding for 15 minutes at a temperature 0.99 ° C.,
By performing heat treatment at 200 ° C. for 5 hours, Examples 1 to 4
A friction material for a disc pad was obtained.

[0020]

Comparative Examples 1 to 4 Comparative Examples 1 to 4 were repeated in the same manner as in Examples 1 to 4 except that a filler other than electrofused magnesia was used.
4 was obtained.

[0021]

[Friction test] With respect to the friction materials of Examples 1 to 4 and Comparative Examples 1 to 4, a friction test (JASO C406-82, Inertia 4) was performed using a full-size dynamo testing machine.
0 kgms ² ), and the wear of the friction material and the rotor after the test was measured. The results are shown in Table 1 below. In addition, the inertia of 40 kgms ² corresponds to a constant load state of a 4-ton to 5-ton vehicle.

[Table 1]

In Table 1, the numerical values of the composition are expressed by volume%,
The efficacy indicates the coefficient of friction at 0.4 g.

[0023]

As is clear from Table 1, when the friction material of the present invention is used, even when a high load is applied,
Excellent abrasion resistance, stable friction performance from low to high speed range, and low face-to-face damage.

On the other hand, when the friction material of the comparative example was used,
When a high load was applied, the abrasion resistance was poor, the friction performance was unstable, and the face-to-face damage was large.

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Claims (4)

(57) [Claims] A non-asbestos-based friction material comprising a reinforcing fiber other than asbestos, a binder made of a thermosetting resin such as phenol resin, and a filler such as barium sulfate, wherein at least a part of the filler is A non-asbestos-based friction material containing electrofused magnesia. 2. The non-asbestos-based friction material according to claim 1, wherein the fused magnesia has an average particle diameter of about 0.05 to about 1.0 mm. 3. The non-asbestos-based friction material according to claim 1, wherein the content of the electrofused magnesia is about 0.5 to about 20% by volume based on the total amount of the friction material. 4. A high-load non-asbestos-based friction material molded article comprising the friction material according to claim 1.