JPH0694057A - Brake noise preventive material - Google Patents

Abstract

PURPOSE:To provide a brake noise preventer consisting of a rubber material, through which durability is improved and a brake noise preventive effect in a brake operation is effectuated. CONSTITUTION:In a brake noise preventer 20 to be inserted to prevent any noise being produced in time of brake operation, into an interval between a friction pad back plate 18, consisting of what a lining material 16 coming into contact with the surface of a disk rotor 24, and a pad pressing member 22 of a caliper 10 holding this pad back plate 18 and pressing it at the time of the brake operation, this noise preventer 20 is made up of a rubber material being comprised of a reinforced fiber consisting of a short fiber with heat resistance such as rock wool or the like and a filler of magnesium oxide or the like mixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake squeal prevention material, and more particularly, to a pad back plate formed by fixing a lining material abutting against a disc rotor surface during brake operation, and the pad back plate. The present invention relates to a brake squeal preventing material that is inserted between a pad pressing member that constitutes a caliper that is gripped and pressed to prevent a squeal that is generated during a brake operation.

[0002]

2. Description of the Related Art Disc brakes, as shown in FIG.
The pads 14, 14 arranged so as to sandwich the disk 24 rotating with the wheels are gripped by the caliper 10,
In addition, when the brake is operated, each pad back plate 18 is pressed by the claw portion 22 of the caliper 10 and the piston 12 so that the lining material 16 of each pad 14 contacts the disk surface. Since a squeal is generated during such a brake operation, a shim 20 as a brake squeal preventing material is inserted between the pad back plate 18 and the claw portion 22 of the caliper 10.

The shim 20 shown in FIG. 3, as shown in FIG.
The pad back plate 18 to which the lining material 16 is fixed is attached by locking pieces 21 and 23. As shown in FIG. 5, the shim 20 conventionally includes a sheet-like rubber material 1 made of rubber such as acrylonitrile-butadiene rubber (NBR) on both sides of a thin metal plate 102 made of metal such as stainless steel.
00 and 100 are attached.

[0004]

DISCLOSURE OF THE INVENTION In the conventional disc brake in which the shim 26 to which the sheet-like rubber materials 100, 100 are attached as shown in FIG. 5 is inserted, the squeal at the time of brake operation can be reduced. By the way, in the shim 20, the pressing member such as the claw portion 22 of the caliper 10 presses the substantially same portion of the shim 20 every time the brake is operated. May cause the thin metal plate 102 to be exposed. In such a situation, the squealing prevention effect is almost eliminated.
As described above, the durability of the rubber material against the pressing member of the caliper 10 is poor in the conventional sheet-shaped rubber materials 100, 100, and the speed at which the squealing prevention effect is eliminated is high. Therefore, it is an object of the present invention to provide a brake squeal prevention member made of a rubber material that has improved durability and exhibits a squeal prevention effect during brake operation.

[0005]

Means for Solving the Problems As a result of repeated studies to achieve the above-mentioned object, the present inventor has succeeded in preventing squeal by mixing rock wool and aramid short fibers, and further magnesium oxide and graphite in a rubber material. The present invention has been accomplished by finding that the durability of the rubber material can be improved while producing the effect. That is, according to the present invention, between the pad back plate formed by fixing the lining material that is in contact with the disc rotor surface during the brake operation, and the pad pressing member forming the caliper that grips and presses the pad back plate. In a squeal prevention material for a brake inserted to prevent squeal generated during brake operation, the squeal prevention material includes a reinforcing fiber made of heat-resistant short fibers such as rock wool and a filler such as magnesium oxide. It is characterized by being a mixed rubber material.

[0006]

According to the present invention, the rubber material can absorb the vibration generated in the pad back plate or the like during the brake operation, and can prevent the squeal that is generated by the vibration of the pad back plate or the like resonating. Also,
The durability of the rubber material is improved by the reinforcing short fibers composed of short fibers having excellent heat resistance such as rock wool oriented in the rubber material and the filler such as magnesium oxide. Furthermore, by mixing a filler such as magnesium oxide, the heat resistance of the rubber material is improved, and the filler such as magnesium oxide exhibits lubricity to the caliper pressing member, so that the caliper pressing member is pressed. At this time, a slip phenomenon occurs between the pressing member and the rubber material. Therefore, in combination with the improvement of the durability of the rubber material, the thinning speed of the rubber material due to the pressing of the pressing member forming the caliper can be slowed down.

[0007]

The rubber material used in the present invention may be a conventionally used rubber material, but rubber such as NBR, styrene-butadiene rubber (SBR) or ethylene-propylene rubber (EPDM) may be vulcanized. A rubber material obtained by applying is preferable. Such vulcanization can be performed while kneading the rubber and a vulcanizing agent such as sulfur, and the vulcanization rate can be improved by adding a vulcanization accelerator such as zinc oxide. Further, as the reinforcing fiber to be mixed with the rubber material, heat resistant short fiber can be adopted, and rock wool, aramid fiber,
Carbon fiber, potassium titanate fiber, ceramic fiber, vermiculite fiber and the like can be preferably used. Such short fibers can be used alone or in plural, and the fiber length is from 2 to 2.
Those having a diameter of 3 mm and a fiber diameter of about 8 to 15 μm are suitable.

Further, in the present invention, a filler such as magnesium oxide is used together. As this filler, in addition to magnesium oxide, barium sulfate, graphite or the like can be preferably used,
These fillers can be used alone or in combination. These reinforcing fibers and fillers can be dispersed and blended in the rubber material by adding and kneading at the time of kneading for vulcanizing the rubber material. A suitable compounding amount of such a compounding material is 15 to 25% by weight of rubber, 50 to 60% by weight of reinforcing fiber, 15 to 25% by weight of a filler, and 1.5 of a vulcanizing agent based on the rubber material finally obtained. ˜3 wt%, vulcanization accelerator 3.5˜7 wt%. If the amount is out of this range, the rubber material finally obtained tends to have insufficient durability improvement or insufficient squealing prevention effect.

As shown in FIG. 1, the obtained rubber material is formed into sheet-like bodies 30 and 30 and attached to both sides of a metal thin plate 28 made of stainless steel to form a shim 20. The sheet-shaped body 30 may be attached to the thin metal plate 28 by using a heat-resistant adhesive or baking. It is also possible to directly coat the thin metal plate 28. The shim 20 to which the sheet-like body 30 is attached in this way
Is attached to the pad back plate 18 to which the lining material 16 is fixed, as shown in FIG. Then, the pad on which the shim 20 is mounted is mounted on the caliper 10 as shown in FIG. Although the shim 20 shown in FIG. 3 is mounted on the claw portion 22 side of the caliper 10, it may be mounted on the piston 12 side or both sides of the claw portion 22 side and the piston 12 side.

Further, as shown in FIG. 2, the sheet-like body 30 may be directly attached to the pad back plate 18 without forming the shim 20, and the claw portion 22 of the caliper 10 and the pad of the piston 12 may be formed. The sheet-like body 30 may be directly attached to the pressing surface side that presses the back plate 18. As described above, the sheet-like body 30 molded from the rubber material formed by mixing the reinforcing fiber made of heat-resistant short fibers and the filler such as magnesium oxide absorbs the vibration generated in the pad back plate during the brake operation. However, it is possible to prevent the squeal that occurs when the vibration of the pad back plate resonates. Further, the sheet-like body 30 has improved durability as compared with the conventional sheet-like body made of only vulcanized rubber, and slips between the pressing member of the caliper 10 due to the compounded filler. The phenomenon occurs. Therefore, even if the pressing member of the caliper 10 repeatedly presses the same portion of the sheet-shaped body 30, the sheet-shaped body 3
The degree of thinning of 0 can be remarkably delayed as compared with the conventional sheet-like body, and the time during which the squealing prevention effect at the time of brake operation can be exerted can be extended. In the present invention, the claw portion 22 of the caliper 10 that presses the pad back plate 18
A rubber material may be embedded in the pressing surface such as without being molded into a sheet-shaped body.

[0011]

The present invention will be described in more detail with reference to the following examples. Example A rubber material was prepared by heating and vulcanizing while mixing the following materials. Rubber: NBR 20% by weight Reinforcing fiber: Aramid fiber 10% by weight Rockwool 40% by weight Filler: Graphite 5% by weight Magnesium oxide 15% by weight Vulcanizing agent: Sulfur 1.5% by weight Vulcanization accelerator: Zinc oxide 3. 5% by weight Next, the obtained rubber material is molded into a sheet-like body 30 having a thickness of 0.5 to 0.8 mm, and the sheet-like body 30 made of stainless steel is attached to both sides by baking to obtain the shim 20 shown in FIG. Was formed. Attach this shim 20 to the pad back plate 18,
As shown in FIG. 3, a pad 14 was attached to the caliper 10. The mileage of an automobile equipped with this caliper 10 is 1
When it reached 5000 km, a brake squeal test was carried out, and it was still possible to prevent squeal. Furthermore, when the sheet-like body 30 of the shim 20 was inspected, the caliper 1
Although there are some pressure marks due to the claw portion 22 of 0, the sheet-shaped body 30 still has a sufficient thickness even in the part where the pressure marks remain.

Comparative Example In the examples, rubber (NBR), vulcanizing agent (sulfur),
A rubber material was prepared in the same manner as in Example except that the rubber material was prepared by heating and vulcanizing while mixing only the vulcanization accelerator (zinc oxide). The prepared rubber material is used as the sheet-shaped body 30 of the embodiment.
Was formed into a sheet-shaped body having the same thickness as in Example 1 to form a shim. Caliper 1 with a pad attached to this shim
0 is mounted on a car. When a brake squeal test was conducted at the time when the automobile traveled the same distance as in the example, it was found that the squeal was considerably large. Furthermore, when the shim was inspected, the caliper 10
There was a deep pressing trace due to the claw portion 22 of the above, and the metal thin plate was exposed at a part of the pressing trace.

[0013]

According to the present invention, the durability of the rubber material pressed by the pressing member of the caliper can be improved, so that the brake squeal can be prevented for a long time during the brake operation. Further, since the durability of the rubber material is improved by the compounding material mixed with the rubber material,
An increase in the cost of the disc brake and the like can be avoided as much as possible without increasing the number of members constituting the shim or the like.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a shim using a rubber material adopted in the present invention.

FIG. 2 is a cross-sectional view showing a state in which a molded body obtained by molding a rubber material used in the present invention is directly attached to a pad back plate.

FIG. 3 is a partial cross-sectional view showing the structure of a caliper.

FIG. 4 is an assembly diagram showing an assembled state of the shim and the pad.

FIG. 5 is a partial cross-sectional view of a shim using a conventional rubber material.

[Explanation of symbols]

 10 Calipers 12 Pistons 14 Pads 16 Lining Materials 18 Pad Back Plates 20 Shims 22 Claws 24 Disc Rotors 28 Metal Thin Plates 30 Sheets

Claims (1)

[Claims] 1. A pad back plate formed by fixing a lining material that is in contact with a disc rotor surface during a brake operation, and a pad pressing member that constitutes a caliper that grips and presses the pad back plate. A squeal preventive material for a brake that is inserted to prevent squeal generated during brake operation, wherein the squeal preventive material is a mixture of reinforcing fibers made of heat-resistant short fibers such as rock wool and a filler such as magnesium oxide. A squeal prevention material for brakes, which is a rubber material formed by