JP2001221267A - Brake pad structure for disc brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple structure preventing noise generating from a brake pad in a disc brake for an automobile or the like. SOLUTION: Fixation of the brake pad with a mounting part is performed by a heat resistant adhesive including an adhesive having damping property for preventing the generation of noise by a heat resistant adhesive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device and, more particularly, to a structure used in an automobile or the like to prevent noise generated by the operation of a brake.

[0002]

2. Description of the Related Art A disk brake A (partial disk brake) as shown in FIG. 10 is used as a brake used in a conventional automobile or the like. In such a disc brake A, noise is generated when the brake is operated.
As shown in FIG. 2, a structure called a noise shim 30 having a structure in which both sides of a thin rubber are sandwiched between two thin steel plates, and a friction material is referred to as a reinforcing steel plate 3 (hereinafter referred to as Back Plate,
/ P) with a roller or a press to prevent noise. For example, an example widely used as an automobile noise shim is a thin (50 μm to 200 μm) material such as butadiene rubber (BR) having excellent damping properties.
μ) There is a structure in which rubber is pressed against a thin steel plate (200 μ to 500 μ) with a roller or a press. There is a structure in which a so-called rubber-coated steel plate is punched out by a press in accordance with the shape of a pad to be used, and is mechanically attached to the B / P side of the pad using a nail or the like and integrated.

The effect of the conventional noise shim is that a rubber-coated steel plate is mounted on the B / P side to absorb (attenuate) vibration generated during braking and reduce vibration energy (sound pressure). It is attached to most pads.

[0004] The problems of the conventional noise shim are as follows: performance degradation due to heat, performance degradation due to pressure, cause of brake noise, and influence on the driver.

[0005] Deterioration of performance due to heat The temperature rises by about 2
When the temperature exceeds 00 ° C., the rubber is thermally deteriorated and gradually loses its effect. At a temperature higher than the temperature, the rubber is thermally decomposed and hardly functions. Once the rubber has been thermally degraded or decomposed, it does not exhibit its function even when cooled.

[0006] Deterioration of performance due to pressure In long-term use (vehicle inspection period), the noise shim is repeatedly pressed against the same portion, and the portion is pressed down to be hard and thin. In some cases, the rubber portion is cut off due to extreme pressure and high temperature, and B / P may be exposed. In this case, it is not only impossible to absorb the vibration at all, but also noise may be generated frequently.

In fact, since the temperature and the pressure are repeatedly applied to the noise shim, the noise shim deteriorates considerably faster than the case where the noise shim is used alone, and can be used without replacement during a normal inspection period (first three years, thereafter every two years). It is not as durable, and is currently replaced by regular inspections.

Cause of Brake Noise and Effect on Driver Pads, which are friction materials, are pressed against the rotating rotor by the brake, and the tangential force generated at that time is controlled to decelerate or stop the vehicle. Function is brake. Vibration due to friction generated when the pad and rotor are not in contact with the original brake function (friction vibration) occurs. If the frequency of the vibration is within the audible range (about 50 to 15,000 cycles), it will be heard as unpleasant noise. come.

This unpleasant sound (brake noise) is usually
Generated frequency is higher than 1000 cycles and can be roughly divided into 2000-4000 cycles, which can be heard by the ear, and 5000-9000 cycles, which is higher than that. The human ear responds sensitively to key sounds with a frequency of 2,000 to 4,000 cycles, so it sounds more unpleasant and unpleasant. The vibration energy of the noise is negligible and does not cause any problem in driving, but it is an undesirable phenomenon because it not only makes the driver uncomfortable but also gives the driver an impression like a sign of a car breakdown and makes the driver uneasy.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above problems of the conventional noise shim, namely, performance degradation due to heat, performance degradation due to pressure, the problem of the cause of brake noise generation and the influence on the driver. A pad integrated structure that eliminates the need for a noise shim to suppress the generation of brake noise by interposing a heat-resistant adhesive with high damping properties as an adhesive between the friction material and the reinforcing material to reduce noise generated when braking the friction material. It is an object of the present invention to obtain a structure having a low manufacturing cost.

Another object of the present invention is to solve the above problems and to simultaneously fix the brake pad and the mounting portion.

[0012]

In order to solve the above-mentioned problems, the present invention provides a brake pad portion and a mounting portion of a disc brake sandwiching a brake disk, and bonding and fixing the pad portion and the mounting portion. In an integrated adhesive layer, and in a brake pad of a disc brake such as a vehicle including a brake piston, the adhesive layer in which the brake pad portion and the mounting portion are bonded and integrated is made of a material having excellent damping properties. A brake pad structure of a disc brake comprising a component of a heat-resistant adhesive containing the adhesive layer. The adhesive layer has a dual function of fixing members by adhesion and preventing generation of noise.

Further, the component constituting the adhesive layer is a viscoelastic heat-resistant adhesive composed of a combination of a damping rubber component and a heat-resistant thermosetting resin such as phenol or epoxy. Component.

The thickness of the adhesive layer is set to 30 to 150 μm from the characteristics of both vibration damping property and heat resistant adhesive strength.
This makes it possible to set the range in terms of both the vibration damping property and the heat resistant adhesive strength in a practically preferable range.

The compounding ratio of the thermosetting resin of the adhesive in the adhesive layer is 50% to 85%, and the compounding ratio of the rubber for damping vibration is about 15% to 60%. In addition, a composition that balances the noise generation rate and the adhesive strength can be selected.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings. As shown in FIG. 1, the brake principle of the disc brake (partial disc brake) is transmitted to the caliper 7 by hydraulic pressure from a hydraulic device (not shown) according to the principle of Pascal, as is well known. The piston 5 is pressed, and the pads 2, 2 made of a friction material are pressed against the brake disk 6 (or the rotor) by the operating force to convert the kinetic energy of the vehicle into thermal energy by the frictional action. ,
It takes away the kinetic energy of the car.

FIG. 3 shows a brake pad 1 of a disk brake according to an embodiment of the present invention. Pad portions 2 are provided on both sides of a brake disk 6 (or rotor) made of a friction material. Have been. The attachment portion 3 is a reinforcing steel plate to which the pad portions 2 and 2 are attached. Pad part 2, 2
Is the reinforced steel plate (abbreviated BACK PLATE, B /
P (hereinafter referred to as P), and an adhesive layer 20 is formed. A piston 5 is provided below the reinforcing plate, which is the mounting portion 3, and presses the pad portions 2, 2 against the brake disk 6 by hydraulic pressure.

In the present invention, the adhesive of the adhesive layer 20 is mainly composed of two components, and focuses on a rubber-based adhesive which is optimal for attenuating the generation of noise. To prevent the occurrence of adhesion and noise. Other components include solvents and the like. It is noted that the position where the adhesive layer 20 is provided is provided between the pad portion 2 and the mounting portion 3 so that vibration causing noise can be more effectively prevented.

As a heat-resistant adhesive, it is needless to say that those skilled in the art can employ well-known adhesives such as phenol, epoxy-modified fettle, melamine, and cyanate. In particular, if a phenolic adhesive, which is a thermosetting resin with excellent adhesive strength and heat resistance at high temperatures, is added and compounded,
It can be a more preferred embodiment, and by changing the compounding ratio in accordance with each required item, a high heat resistant adhesive layer with less noise is formed. For example,
Phenolic adhesives, which are thermosetting resins, have excellent adhesive strength and excellent heat resistance. Rubber adhesives are partially softened and are ideal for attenuating generated noise by attenuating vibration. Since it is an adhesive, it can be appropriately compounded and used according to the required functions and use conditions. In addition, if a thermosetting resin is used as the adhesive, there is an advantage that the adhesive can be easily adhered and fixed by heating in production.

FIG. 4 shows an example in which the pad of the present invention is compared with a conventional product which has been conventionally used (the conventional product is a test material made of an epoxy-modified phenol which is generally used as an automobile pad). As shown, the noise test results when the number of brakes was set to 200 under the test conditions clearly show that the pads of the present invention have reduced noise generation. It was confirmed that the performance deterioration due to the heat generated from the brake was cleared compared to the conventional product.

The adhesive strength is considered to be slightly lower because the rubber-based adhesive component is included, but the energy required for peeling the pad is multiplied by the force required for peeling and the distance required for peeling. In the experiment, the energy of destruction is almost the same, or the value in the present invention is slightly larger than that of the conventional current product as shown in FIG.

Further, as a result of the experiment, it has been found that, in the present invention, when the mixing ratio of the rubber-based adhesive and the heat-resistant adhesive is changed with respect to the current product, the noise generation rate increases or decreases. Although a phenolic resin of a thermosetting resin is used as the heat-resistant adhesive, as shown in FIG. 6, when the amount of rubber is increased, that is, when the amount of phenolic resin is reduced, noise generation is reduced. I understand. However, in practice, sufficient adhesive strength is required to withstand long-time use of the pad portions 2 and 2 of the brake pad 1, and the generation of unpleasant noise that satisfies comfortable driving is reduced. 2
One of the conditions must be satisfied.

Further, as shown in FIG. 7, it is known that changing the mixing ratio of the rubber-based adhesive and the heat-resistant adhesive (thermosetting resin: phenol-based adhesive) affects the adhesive strength as shown in FIG. Was done. As the amount of rubber increases, the noise generation rate decreases. On the contrary, as shown in FIG. 7, the adhesive strength gradually decreases.

From the relationship between FIG. 6 and FIG. 7, the mixing ratio of the adhesive in the adhesive layer is 50% based on the characteristics of both the noise generation rate and the adhesive strength.
85%, the compounding ratio of rubber that dampens vibration is 15%
It is about 60%. Phenolic resins have different physical properties depending on the melting point (° C.), gel time (sec), flow (mm), and the like, and there are considerable differences because the characteristics and performance of the products of each manufacturer are not standardized.

Since the noise generation rate (attenuation) is also an important factor related to the thickness of the adhesive layer, the relationship between the thickness of the adhesive layer and the adhesive force is shown in FIG. FIG. 9 shows the relationship with the ratio. Conventionally, it is empirically known that the relationship between the thickness of the adhesive layer and the adhesive strength generally tends to be higher when the adhesive layer is thinner. That is,
As shown in FIG. 8, the adhesive force decreases as the thickness increases. The adhesive strength is preferably such that the thickness of the adhesive layer is small.
0 to 30 μm was good. When it exceeds 120 μm, the adhesive strength starts to gradually decrease. Also, it has been found from experiments that when the thickness exceeds 150 μm, the stroke of the brake petal increases in the actual vehicle, and the petal feeling deteriorates.

Further, it has been known that the noise generation rate decreases as the number of adhesive layers increases, as shown in FIG. It is known that the more adhesive layers, the better the damping property. However, when the thickness of the layer is 10 to 20 μm, the effect of reducing noise is not recognized or is small.

As described above, if the number of adhesive layers increases, the adhesive force gradually decreases, and the noise generation rate decreases. Therefore, in practice, it is necessary to maintain the adhesive force and reduce the noise generation rate. . The thickness of the adhesive layer is 10 to 20 μm
Then, the effect of reducing the noise generation rate is not recognized or the effect is small. On the other hand, when the thickness is 10 to 30 μm, the adhesive strength is conversely good. Therefore, the thickness of the adhesive layer is preferably in the range of 30 to 150 μm in consideration of both in a practical range.

[0028]

As described above, the present invention provides a brake for a disc brake provided with an adhesive layer formed by adding a rubber-based adhesive having excellent damping properties to a heat-resistant adhesive and bonding and fixing the rubber-based adhesive. Because of the use of the pad, a brake pad for a disc brake with extremely little noise over a long period of time under high load use, which was difficult to achieve by itself, compared to the conventional one, was obtained.

Further, unlike a conventional brake pad of a disc brake, an independent noise shim is not required, and a reinforcing steel plate and a pad portion, which is a mounting portion, are integrated with an adhesive to form an integral structure. , And the two effects of reducing the noise generation rate can be simultaneously achieved.

In particular, a high-strength, heat-resistant resin having excellent heat-resistant adhesive strength is used as a heat-resistant adhesive, and a rubber-based adhesive having excellent damping properties is added to the heat-curable resin to bond and fix the adhesive layer. When formed, a brake pad for a disc brake having higher heat resistance and a lower noise generation rate can be obtained.

Further, the conventional noise shim has a structure in which a rubber-coated steel plate is attached to the reinforcing steel plate to absorb (attenuate) the vibration generated during braking, so that it is necessary to separately manufacture and attach a member, which requires a work process. Although the manufacturing cost is high in many cases, according to the present invention, the brake pad of the disc brake can be obtained at a reduced cost because it is only formed integrally with the adhesive.

Further, the conventional noise shim has a structure in which a separate rubber-coated steel plate is attached to the reinforcing steel plate. However, in the present invention, the weight can be reduced because only the adhesive layer is provided.

The human ear reacts sensitively to the conventionally generated key sound having a frequency of 2,000 to 4,000 cycles, so that the sound is heard as a more unpleasant and unpleasant sound. Has no problem,
This is an undesirable phenomenon that not only makes the driver uncomfortable, but also gives the driver an impression like a sign of car breakdown, and makes the driver uneasy.However, the present invention guarantees comfortable driving due to the reduced noise generation rate. It became a thing.

[Brief description of the drawings]

FIG. 1 is a principle diagram for explaining the principle of a conventional disc brake.

FIG. 2 shows an example of a brake pad in a conventional disc brake.

FIG. 3 shows an embodiment of a brake pad of a disc brake according to the present invention.

FIG. 4 shows a comparison test result of a noise generation rate after a heat history in an example of the present invention with a current product.

FIG. 5 shows the results of a comparison test of the adhesive peel energy between the brake pad of the disc brake according to the embodiment of the present invention and a current product.

FIG. 6 shows a test result of the noise generation rate and the adhesive component ratio of the brake pad of the disc brake according to the embodiment of the present invention.

FIG. 7 shows test results of the adhesive force and the adhesive component ratio of the pad portion of the brake pad of the disc brake according to the embodiment of the present invention.

FIG. 8 shows a test result of a thickness and an adhesive strength of an adhesive layer of a pad portion of a brake pad of a disc brake according to an embodiment of the present invention.

FIG. 9 shows test results showing the relationship between the thickness of the adhesive layer at the pad portion of the brake pad of the disc brake according to the embodiment of the present invention and the noise generation rate.

FIG. 10 is an overall view showing the appearance of a conventional disc brake.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake pad 2 Pad part 20 Adhesive layer 3 Mounting part (reinforced steel plate) 30 Noise shim 5 Piston 6 Brake disk (or rotor) 7 Caliper

Claims (4)

[Claims] 1. A disk brake for a vehicle or the like, comprising: a brake pad portion sandwiching a brake disk, a mounting portion, an adhesive layer integrally bonding and fixing the pad portion and the mounting portion, and a brake piston. In the brake pad, the adhesive layer in which the pad portion and the mounting portion are bonded and integrated,
A brake pad structure for a disc brake, comprising a component of a heat-resistant adhesive containing a material having excellent damping properties. 2. The heat-resistant adhesive layer has a viscoelastic heat-resistant composition composed of a combination of a damping rubber-based component and a heat-resistant thermosetting resin such as phenol or epoxy. The brake pad structure for a disc brake according to claim 1, wherein the brake pad structure is a conductive adhesive. 3. A brake pad structure for a disc brake according to claim 1, wherein said adhesive layer has a thickness of 30 to 150 μm in view of characteristics of both vibration damping property and heat resistant adhesive strength. 4. The compounding ratio of the adhesive in the adhesive layer is as follows:
From the characteristics of both the noise generation rate and the adhesive strength, thermosetting resin is 50% to 85%, and rubber for damping vibration is 15% to
4. The method according to claim 1, wherein the amount is about 60%.
The brake pad structure of the disc brake described.