JPH11132271A - Brake pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve friction properties of a brake pad using a metallic pad. SOLUTION: A brake pad 5 is used for a disc brake 1 to brake a disc 2, and it is provided with back plates 6, frictional materials 7 and carbon 8. Each frictional material 7 is fixed to one surface of the back plate 6 and faces the disc 2. The friction materials 7 are made of a metallic material. Carbon 8 is arranged on the front surface of the friction materials 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a brake pad,
In particular, it relates to a brake pad used for a disk brake of a vehicle.

[0002]

2. Description of the Related Art Disc brakes are used to generate a braking force by pressing pads on both surfaces of a disc that rotates together with wheels. The disc brake includes a caliper, a piston supported by the caliper, and a brake pad driven by the piston and biased on both surfaces of the disc.

[0003] The disk pad is composed of a back plate and a friction material fixed to the back plate. As the material of the friction material, an organic type (resin mold), a semimetal (semi-metallic), an inorganic type (metallic), or the like is used. In general, resin molds are used, but they are faster to wear than other materials and lack moisture resistance. Semi-metallics include those based on steel fibers and those based on inorganic fibers such as glass and carbon. In both cases, the binder is phenolic resin. Semi-metallics tend to transfer heat, so brake fluids tend to be hot. Metallic is made of a sintered alloy by powder metallurgy and has the highest performance.

[0004] The main component of the metallic friction material is copper powder, and the additives are tin, lead, graphite and the like. The metallic friction material made of a metallic material is manufactured by heating and sintering a material mixed with the above-mentioned materials and sintering the material on a back plate. Further, as a metallic friction material, a ceramic metallic pad using ceramic has been developed.

[0005]

The above-mentioned conventional brake pad using a metallic friction material has high performance at a high temperature, little wear under severe conditions, and good water recoverability. However, on the other hand, there is a problem that the squeal and the aggressive material aggressiveness are inferior, and chatter vibration is easily generated. .

It is an object of the present invention to improve the friction characteristics of a brake pad using a metallic friction material.

[0007]

According to a first aspect of the present invention, there is provided a brake pad for use in a disk brake for braking a disk, comprising a back plate, a metallic friction material, and carbon. The metallic friction material is fixed to one surface of the pack plate and faces the disk. Carbon is arranged on the surface of the metallic friction material.

When the brake pad is pressed against the disk, friction causes the surface of the metallic friction material to wear, and at this time, carbon also wears. The worn carbon adheres to the disc and further to the surface of the metallic friction material of the brake pad. By the carbon adhered to the friction surface in this way, for example, a decrease in the friction coefficient at a high temperature is suppressed. In addition, problems such as squeal and chatter vibration during operation hardly occur.

According to a second aspect of the present invention, in the brake pad according to the first aspect, the carbon has a block shape arranged in a concave portion formed in the metallic friction material. According to a third aspect of the present invention, in the brake pad according to the second aspect, a plurality of carbons are arranged.

[0010]

FIG. 1 shows a disc brake 1 as an embodiment of the present invention. This disc brake 1
Is a fixed caliper type. The brake 1 mainly includes a disk 2, a caliper 3, a cylinder 13, and a brake pad 5.

The disk 2 rotates integrally with the vehicle wheel. The caliper 3 is fixed to another member.
The caliper 3 has receiving portions 3a arranged on both sides of the disk 2 in the axial direction. The cylinders 13 are arranged in the receiving portions 3a, respectively. The cylinder 13 includes a hydraulic chamber 11 formed in each receiving portion 3a and the piston 4 disposed therein. The hydraulic chamber 11 communicates with a master cylinder (not shown) via an oil passage 12. The piston 4 is arranged in the hydraulic chamber 11 so as to be movable in the disk axial direction and not to rotate relatively. Between the piston 4 and the disk axial surface 11a of the hydraulic chamber 11,
A spring 9 (coil spring) is arranged. Also,
A seal 10 for sealing the hydraulic chamber 11 is disposed between the outer peripheral surface 4a of the piston 4 and the peripheral wall surface 11b of the hydraulic chamber 11.

A brake pad 5 is arranged between the disk 2 and the piston 4. The brake pad 5
As is clear from FIG. 2 and FIG. 3, it is a plate-like member extending in one direction. The brake pad 5 mainly includes a back plate 6 and a friction material 7 fixed to the back plate 6. The back plate 6 is arranged on the tip side of the piston 4. The friction material 7 is fixed to the main surface of the back plate 6 and faces the disk 2 side. The friction material 7 is made of a ceramic metallic sintered material,
It is fixed to the back plate 6 by sintering. A groove 1 extending in the radial direction is provided at the center of the friction material 7 in the disk radial direction.
4 are formed.

A plurality of carbons 8 are arranged on the friction material 7. The carbon 8 is exposed on the surface of the friction material 7. The carbon 8 has a columnar shape as a whole, and the exposed surface is a circle. The carbon 8 has a single lump or block shape, is fitted in a hole formed in the friction material 7, and is in contact with the back plate 6 in the hole. More specifically, the carbon 8 is arranged at four locations in the circumferential direction. A pair of carbons 8 on both sides in the circumferential direction are arranged radially inward, and a pair of carbons 8 in the middle in the circumferential direction.
Are arranged radially outward.

In the brake pad 5, at both ends of the back plate 6, engagement portions 15 each formed of two projections or notches projecting in the disk circumferential direction are formed.
The engaging portion 15 is engaged with the caliper 3, whereby the brake pad 5 rotates integrally with the caliper 3. When hydraulic oil is supplied from a master cylinder (not shown) to the cylinder 13 via the oil passage 12, a pair of pistons 4 arranged on both sides of the caliper 3
Urges the pair of brake pads 5 toward the other side. As a result, the disk 2 is sandwiched between the two brake pads 5, and a braking force acts on the disk 2.

The surface of the brake pad 5, that is, the friction 7, is worn by sliding with the disk 2. At this time, the carbon 8 wears together with the friction material 7 and becomes powdery, and adheres to the disk 2 which is a mating member. Further, the carbon adhered to the disk 2 adheres to the surface of the friction material 7. The following effects can be obtained by attaching carbon to the friction surface of each member as described above.

1) By improving lubricity, squeal and judder are reduced. Furthermore, the opponent's attack amount is reduced. 2) A decrease in friction coefficient at high temperatures is suppressed. The best friction characteristics can be obtained when the ratio of the carbon surface area to the friction material surface area is about 30 to 50%. [Other Embodiments] The exposed surface of the carbon 16 shown in FIG. 4 is triangular. That is, each carbon 16 has a triangular prism shape. Thus, the shape of the exposed carbon is not limited and may be any shape.

In the brake pad 5 shown in FIG. 5, the carbon 17 is disposed in a groove formed in the friction material 7.
Specifically, the three carbons 17 extend substantially linearly in the radial direction. Also in this case, each carbon 17 has an elongated block shape extending in one direction. The shapes of the groove and the carbon are not limited to those shown in FIG. In the brake pad 5 shown in FIG. 6, the hole formed in the friction material 7 does not reach the back plate 6, and as a result, the carbon 18 does not reach the back plate 6.

The brake pad according to the present invention is not limited to one used for a caliper fixed type disc brake. Can be adopted for caliper immovable type.

[0019]

In the brake pad according to the present invention, carbon powder generated by wear adheres to the friction surface between the brake pad and the disk. As a result, for example, a decrease in the friction coefficient at a high temperature is suppressed. In addition, problems such as squeal and chatter vibration during operation hardly occur.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a brake to which an embodiment of the present invention is applied.

FIG. 2 is a plan view of a brake pad as one embodiment of the present invention.

FIG. 3 is a view taken in the direction of arrow III in FIG. 2;

FIG. 4 is a view corresponding to FIG. 2 in another embodiment.

FIG. 5 is a diagram corresponding to FIG. 2 in another embodiment.

FIG. 6 is a view corresponding to FIG. 3 in another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake 2 Disk 3 Caliper 4 Cylinder 5 Brake pad 6 Plate 7 Friction material 8, 16, 17, 18 Carbon

Claims (3)

[Claims] 1. A brake pad used for a disc brake for braking a disc, comprising: a back plate; a metallic friction material fixed to one surface of the back plate and facing the disc; and a surface of the metallic friction material. Brake pads with carbon and 2. The brake pad according to claim 1, wherein said carbon has a block shape arranged in a concave portion formed in said metallic friction material. 3. The brake pad according to claim 2, wherein a plurality of said carbons are arranged.