JPH0989024A - Friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction material having excellent wear resisting performance (especially, in a high temperature and at a high speed) without generating any brake squeaking by arranging the center part of a friction member in a manner that the fiber portion of a fiber material is placed in a direction orthogonal to a friction surface and arranging parts other than the center part in a parallel direction. SOLUTION: A part 3 as the center part of a friction member 5 with the fiber portion 2 of a fiber material arranged in a horizontal direction is preliminarily formed by applying pressure from an upper side to a friction material composition uniformly mixed by a mixer. Then, a portion 4 other than the center part of the friction member 5 with the fiber portion of a fiber material arranged in a horizontal direction is preliminarily formed by horizontally positioning the preliminarily formed portion 3 in the center of the friction material and applying pressure from an upper side to a friction material composition in its periphery. Then, the preliminarily formed portions 3 and 4 in which the fiber portions 2 in a back metal 6, in the center part and the portion other than the center part are different from one another are inserted in a metallic mold, subjected to heating and pressurizing, calcined and then by polishing these after cooling, a disk brake pad is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material such as a disc brake pad and a brake lining used for braking an automobile.

[0002]

2. Description of the Related Art Disc brakes are used as braking devices for automobiles, and non-asbestos disc brake pads are used as the braking members. Currently, non-asbestos type disc brake pads are mainly used as reinforcing fibers such as steel fibers, brass fibers, metal fibers such as copper fibers, and aramid as disclosed in JP-B-59-4462 and JP-A-6-184525. Fibers, organic fibers such as acrylic fibers and phenol fibers, inorganic fibers such as alumina silica fibers, rock wool, potassium titanate fibers and carbon fibers are used.

However, the conventional non-asbestos type disc brake pad has a problem in the reinforcing effect of fibers and heat resistance, and the abrasion resistance tends to be inferior.

As a countermeasure against the above problem, it is conceivable to increase the compounding ratio of a solid lubricant such as graphite.
Increasing the blending ratio of the solid lubricant such as graphite causes problems such as a decrease in the friction coefficient and difficulty in preventing abnormal noise called brake squeal.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a friction material which is excellent in wear resistance (especially at high temperature and high speed) without deteriorating friction performance and does not cause brake squeal.

[0006]

The present invention provides a fibrous material,
A friction material including a friction modifier and a binder, in which the central portion of the friction member orients the fibrous substance of the fibrous substance in a direction orthogonal to the friction surface, and the other portions than the central portion are oriented in a parallel direction. .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, examples of the fibrous substance include organic fibers such as aramid fibers, acrylic fibers, phenol fibers, cellulose fibers, glass fibers and ceramic fibers similar to those used in conventional friction materials. Inorganic fibers such as rock wool, calcium silicate fibers and carbon fibers, and metal fibers such as steel fibers, copper fibers, brass fibers and bronze fibers, or a mixture of two or more kinds of fibers is used. The content of the fibrous substance is preferably in the range of 30 to 50% by weight based on the friction material composition.

Examples of the binder include phenol resin, urea resin, melamine resin, modified resins thereof, aromatic polyimide resin, polyacetal, NBR powder, and the like.
These 1 type or 2 types or more can be used.
The content of the binder is 9 to 18% by weight based on the friction material composition.
Is preferred.

Examples of the friction modifier include graphite, barium sulfate, friction dust, antimony trisulfide, ceramic powder, metal powder, and the like, or one or two of them.
More than one type can be used. The content of the friction modifier is preferably in the range of 40 to 60% by weight based on the friction material composition.

The ratio (ratio) between the central portion of the friction member and the portion other than the central portion in the present invention is not particularly limited, but a portion of about 50 to 70% by volume of the substantially central portion of the friction member is the central portion. It is preferable that the other portion, specifically, the portion surrounding the central portion is the portion other than the central portion.

Embodiments of the present invention will be described below in detail with reference to the drawings. 1A, 1B and 1C are perspective views showing a manufacturing state of a disc brake pad according to an embodiment of the present invention, and FIG. 1A shows a preform of a central portion,
(B) shows a preform obtained by orienting a fiber material having a different direction from that of the preform obtained in (a), and (c) shows a disc brake pad. FIG. 2 is a sectional view of a friction member of a disc brake pad according to an embodiment of the present invention. In FIGS. 1 and 2, 1 indicates the pressure direction, 2 is a fibrous material, 3 is a preform of the central portion of the friction member, 4 is a preform other than the central portion, 5 is a friction member, 6 is a back metal and 7 Is a friction surface.

In the friction material according to the present invention, for example, a disc brake pad, first, the fibrous substance of the fibrous substance in the friction material composition is oriented in a direction orthogonal to the friction surface to form a central portion of the friction member. Is preformed, and then the fiber material of the fibrous substance is oriented parallel to the friction surface around the preform to preform a portion other than the central portion of the friction member. It is obtained by molding the back metal and the above preform by a heat and pressure molding method.

[0013]

EXAMPLES Examples of the present invention will be described below. Example 1 The components shown in Table 1 were blended and uniformly mixed with a mixer to obtain a friction material composition. Next, as shown in FIG. 1 (a), the friction material composition obtained above is applied with pressure from above to form a central portion of the friction member in which the fibrous substance 2 of the fibrous substance is oriented in the lateral direction. Preforming, and then, as shown in FIG. 1B, the preform 3 at the center of the friction member obtained in FIG. A portion other than the central portion of the friction member in which the fibrous material 2 of the fibrous substance was oriented in the lateral direction was preformed by applying pressure from above.

Thereafter, the back metal 6 and the preforms in which the directions of the fibers 2 in the central portion and the portions other than the central portion are different from each other are inserted into the mold, and then 152.5 ± 2.5 ° C. and a pressure of 49 MPa. Heat and pressure molding for 5 minutes under the conditions, then 200
The disc brake pad was baked at 5 ° C. for 5 hours, cooled, and then polished to obtain a disc brake pad as shown in FIG. The proportion of the center portion of the friction member 5 of the obtained disc brake pad, specifically, the proportion of the fibers 2 in the center portion of FIG. 2 oriented in the direction orthogonal to the friction surface 7 was 60% by volume. .

Comparative Example 1 The friction material composition obtained in Example 1 was preformed into a disc brake pad shape without being divided into a central portion and portions other than the central portion. The disc brake pad was inserted after the same conditions and steps as in Example 1.

[0016]

[Table 1]

Next, the wear resistance performance of the disc brake pad according to the present invention (Example 1) and the disc brake pad not included in the present invention (Comparative Example 1) under the conditions shown in Table 2 was measured using an inertia dynamometer. It was measured. Regarding the squealing characteristics, an actual vehicle [vehicle weight: 1180 kg, brake type: collet type (cylinder area: 25 cm ² ), automatic vehicle] was run in the city (1000 km) and evaluated for sensitivity. Table 3 shows the results together.

[0018]

[Table 2]

[0019]

[Table 3]

As shown in Table 3, it can be seen that the disc brake pad according to the present invention has a small amount of wear and no brake squeal. On the other hand, the disc brake pad not included in the present invention has a drawback that a large amount of wear causes brake squeal.

[0021]

INDUSTRIAL APPLICABILITY The friction material according to the present invention is a friction material which is excellent in abrasion resistance without lowering friction performance and does not cause brake squeal.

[Brief description of drawings]

1 (a), (b) and (c) are perspective views showing a manufacturing state of a disc brake pad according to an embodiment of the present invention, (a) showing a preform in a central portion, b) shows a preform obtained by orienting a fiber material having a different direction from that of the preform around the preform obtained in (a), (c)
Indicates a disc brake pad.

FIG. 2 is a sectional view of a friction member of a disc brake pad according to an embodiment of the present invention.

[Explanation of symbols]

 1 pressure direction 2 fibrous material 3 preform of the central part of the friction member 4 preform other than the central part 5 friction member 6 back metal 7 friction surface

Claims (1)

[Claims] 1. In a friction material containing a fibrous substance, a friction modifier and a binder, the central part of the friction member is oriented in a direction orthogonal to the friction surface in the fibrous substance of the fibrous substance, and is parallel except for the central part. Friction material oriented in the same direction.