JP3152124B2 - Hybrid brake pads - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a hybrid brake pad. The present invention can be used, for example, for a brake pad of a vehicle.

[0002]

2. Description of the Related Art In brake pads, there is a demand for a further reduction in brake "squeal" during braking. Further, besides "reduction of squeal", further improvement of "effect" by a brake is also demanded. By the way, as a hybrid brake pad with a structure combining multiple friction materials,
A structure in which a friction material having high wear resistance is arranged on the outer peripheral side and a friction material having low wear resistance is arranged on the inner peripheral side is known (Japanese Utility Model Application Laid-Open No. Sho 56-113241).

[0003]

However, the hybrid brake pad according to the above-mentioned publication is intended to equalize the amount of wear in the radial direction, and to reduce "squeal".
It is not intended. Furthermore, it is not intended to achieve both "reduction of squeal" and "effectiveness". The present invention has been made in view of the above-mentioned circumstances, and the subject of claim 1 is:
It is an object of the present invention to provide a hybrid brake pad having a structure which is advantageous for "reduction of squeal" and therefore easily achieves both "reduction of squeal" and "effectiveness".

[0004] Further in the challenge claim 2, in addition to the problems described above, mixed due to frictional drag, it is advantageous for suppressing the fluctuation in turn friction characteristics, to maintain good frictional properties for a long time Another object of the present invention is to provide a hybrid brake pad which is advantageous to the above.

[0005]

Means for Solving the Problems The inventor of the present invention has been diligently developing to solve the above-mentioned problems, and has shown that the brakes are effective.
A friction material with a good high friction coefficient is disadvantageous in terms of "reduction of squeal", while a friction material with low friction coefficient which is advantageous in terms of "reduction of squeal" is disadvantageous in terms of "effectiveness" We noticed that there is a tendency, and that "squeal" tends to occur when the brake pedal is lightly depressed. Further, it has been found that if the friction material having a low friction coefficient is made to preferentially rub against the other material at the time of light stepping, it is advantageous in terms of "reduction of squealing". The brake pad according to was completed.

Further, the inventor of the present invention has proposed that "the reduction of squeal" can be attained by making the compression elastic modulus of a friction material having a low friction coefficient projecting from other parts smaller than the compression elastic modulus of a friction material having a high friction coefficient.
Although it is advantageous in terms of the effect, it is easy to compress the friction material with a low coefficient of friction that is not necessarily sufficient in terms of the "effectiveness" at high stepping, so that the friction material with a high coefficient of friction that is advantageous in the "effectiveness" at high stepping Paying attention to the fact that friction with the mating material becomes easy, the brake pad according to claim 1 is completed.

Further, the present inventor can reduce the wear of the low friction coefficient friction material by setting the wear rate of the low friction coefficient friction material to be smaller than that of the high friction material. Focusing on the fact that the structure for projecting the material is easily maintained for a long period of time, the brake pad according to claim 1 was completed. That is, the hybrid brake pad according to claim 1, the phase
In contrast, a friction material with a low coefficient of friction
A hive composed of a combination of a friction material with a high friction coefficient
Lid brake pad with relatively low coefficient of friction
Friction material protrudes from other parts,
Low-friction materials have higher friction coefficients than friction materials.
Also has a low compression modulus and relatively low friction coefficient
Friction materials have a higher wear rate than friction materials with relatively high friction coefficients.
Is small .

[0008]

[0009] The hybrid brake pad according to 請 Motomeko 2, Oite to claim 1, relatively low friction coefficient of friction material, relatively friction coefficient is high friction material, distribution along the frictional sliding direction It is characterized by being provided.

[0010]

According to the first aspect of the present invention, since the friction material having a relatively low friction coefficient protrudes, the friction material having a low friction coefficient preferentially rubs against the counterpart material when the brake is lightly depressed. . This makes it easier to suppress "squeal" during light pedaling. In addition, when the brake pedal has a high pedaling force, the friction material having a high friction coefficient slides against the counterpart material, so that the "effectiveness" of the braking property is secured.

According to the present invention , a friction material having a relatively low friction coefficient has a smaller compression modulus than a friction material having a relatively high friction coefficient, and is softer than a friction material having a higher friction coefficient. Yes, it is compressed by the mating material and easily retracted. Therefore, even when a friction material having a low friction coefficient protrudes in a normal state, at the time of high pedaling force, the share of the compressive load of the friction material having a high friction coefficient is increased, and the "effectiveness" of the brake is secured.

Further, since a friction material having a low friction coefficient is compressed by a mating material and is easily retracted, the frictional material having a low compression load share and a low friction friction coefficient tends to be suppressed. Therefore, the protrusion structure of the friction material having a low friction coefficient is easily maintained. Further, according to the present invention , a friction material having a relatively low friction coefficient has a smaller wear rate than a friction material having a relatively high friction coefficient, and therefore has a smaller wear amount than a member having a higher friction coefficient. When the brake is released, the friction material having a low friction coefficient is more likely to protrude than the friction material having a high friction coefficient. That is, the protrusion structure of the friction material having a low friction coefficient is easily maintained.

According to the second aspect, the friction material having a low friction coefficient and the friction material having a high friction coefficient are arranged along the friction sliding direction, so that the hybrid brake pad frictionally slides with the mating material. Even in such a case, it is possible to prevent a friction material having a low friction coefficient and a friction material having a high friction coefficient from being mixed due to drag of the friction material. The friction material having the above-described characteristics can be constituted by appropriately changing the types and the mixing ratios of the base material, the friction and wear modifier, and the binder.

As the substrate, an organic substrate composed of organic fibers and the like and an inorganic substrate composed of inorganic fibers and the like can be appropriately selected. Aramid fibers (para-based), rayon, polyamide fibers, acrylic fibers, and the like can be used as the organic fibers, and steel fibers, copper wires, and the like can be used as the inorganic fibers. Rubber, cashew, baryta, calcium carbonate, graphite, molybdenum disulfide, alumina, silica, and the like can be appropriately selected as the friction and wear adjusting agent. As the binder, a phenol resin, a melamine resin, an epoxy resin, or the like can be employed.

[0015]

【Example】

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described. This embodiment is applied to a disc brake pad of a vehicle. FIG. 1 shows a state in which a brake pad 1 is mounted on a back metal 2, and FIG. 2 shows a cross section taken along line AA in FIG. B indicates the rotation center of the disc brake rotor.

The brake pad 1 has a first friction coefficient which is low.
It is configured by combining a friction material 3 and a second friction material 4 having a high friction coefficient. In FIG. 1, the area of the first friction material 3 having a low friction coefficient is indicated by oblique lines, and has a large radius of curvature having a predetermined width M along the friction sliding direction, that is, the rotation center B of the disc brake rotor. Arrow B as center
It is arranged substantially coaxially in an arcuate band in three directions. The remaining area of the brake pad 1 is a second area having a high friction coefficient.
The friction material 4 is provided.

The exposed area of the second friction material 4 is larger than the exposed area of the first friction material 3. According to the present embodiment, in a normal state, as shown in FIG. 2, the first friction material 3 having a low friction coefficient protrudes by ΔL1 from the second friction material 4 having a high friction coefficient. Note that ΔL1 can be appropriately selected according to the type of the brake pad 1, the use conditions, the demand for the brake feeling, and the like.
In particular, it can be set to 0.3 mm or less, but is not limited to this. Depending on the type of the brake pad, it can be set to about 1 mm depending on the case. When ΔL1 becomes excessive, the brake feeling generally decreases.

Hereinafter, the low friction coefficient used in the present embodiment will be described.
The characteristics of the first friction material 3 and the second friction material 4 having a high friction coefficient will be described.
I will tell. (A) First friction material 3 having low coefficient of friction 3 Friction coefficient μ_L: 0.25 compression modulus E_L: 10 [kg / mm^Two] (Brake pressure:
10 kg / cm^Two]) Wear rate W_L: 0.9 × 10^-Four[Kgf ・ m ・ s^Two(B) Second friction material 4 with high friction coefficient Friction coefficient μ_H: 0.4 Compression modulus E_H: 110 kg / mm^Two〕(brake
Pressure: 10 [kg / cm^Two]) Wear rate W_H: 2.4 × 10^-Four~ 2.5 × 10^-Four[Kgf
・ M ・ s^TwoHere, (Wear rate W of second friction material 4)_H/ Of the first friction material 3
Wear rate W_L) Is about 2.8. Also the first friction material
The area of 3 is A_LAnd the area of the second friction material 4 is A _HTo be
And A_H/ A_L= 2.8.

The coefficient of friction was determined by a test method in accordance with JASO C406 (test method for passenger car brake tynamometer). The compression modulus is determined by compressing a friction material (thickness t, area A) in a thickness direction at a predetermined pressure F, measuring a compression amount δ, and calculating a compression modulus E = (F / A) / (δ / t). I asked. The wear rate is decelerated at a deceleration of 0.2 G by a brake from a vehicle speed of 50 km / h and stopped. This is repeated a predetermined number of times, and the average value of the decrease in the thickness of the friction material is taken as the wear amount, and the wear rate is measured therefrom. did.

Table 1 shows the basic compositions of the first friction material 3 having a low friction coefficient and the second friction material 4 having a high friction coefficient according to this embodiment.

[0021]

[Table 1] Note that rubber dust can contribute to a reduction in compression modulus. Steel fibers can contribute to securing the coefficient of friction.

As can be understood from the above description, the present embodiment
According to the friction coefficient μ of the first friction material 3, _LIs the second friction material 4
Friction coefficient μ_HSmaller than (μ_L<Μ_H).
Also, the compression elastic modulus E of the first friction material 3_LIs the pressure of the second friction material 4
Shrink modulus E_H(E_L<E_H).
Also, the wear rate W of the first friction material 3_LIs the wear rate of the second friction material 4
W_H(W_L<W_H), First friction
The material 3 is hard to wear.

According to this embodiment having the above configuration, FIG.
As can be understood from FIG. 2, the first friction material 3 having a low friction coefficient protrudes from the second friction material 4. Therefore, at the time of the light pedaling force of the brake, the first friction material 3 having a small friction coefficient and effective for “reduction of squealing” firstly rubs against the disk brake rotor, that is, the mating material 6. Thereby, the problem of "squeal" at the time of the light pedaling force of the brake is reduced and avoided.

At the time of high pedaling force with increased brake depression, as can be understood from FIG. 3, the first frictional member 3 is compressed, and the second frictional member 4 having a high friction coefficient μ _H and strong in “effectiveness”.
Also rub against the mating material 6. Therefore, when the pedaling force is high, the "effectiveness" of the brake is also ensured. Further, according to the present embodiment, since the compression elastic modulus E _L of the first friction material 3 is small, the first friction material 3 is softer than the second friction material 4 and has a characteristic of being easily compressed and retracted by the mating material 6. Thus, at the time of Koto force increased depression of the brake, compression modulus E _L is the smaller first friction material 3 compressed proceeds. Therefore, the second friction material 4 having a high friction coefficient μ _{H and} having a strong “effectiveness” is more easily rubbed against the counterpart material 6. This is advantageous for improving the "effectiveness" of the brake when the pedaling force is high.

Furthermore, according to this embodiment, the first friction material 3
Since the wear rate W _L less than the wear rate W _H of the second friction member 4, the wear of the first friction member 3 is relatively small compared to the second friction member 4. Therefore, when the depression of the brake is released, the first friction member 3 having a low friction coefficient is more likely to protrude than the second friction member 4 having a high friction coefficient. as a result,
The protruding structure of the first friction material 3 shown in FIG. 2 is easily maintained.

In addition, according to this embodiment, as can be understood from FIG. 1, the first friction material 3 having a low friction coefficient and the second friction material 4 having a high friction coefficient are arranged substantially coaxially, and both are frictionally slidable. They are arranged along the moving direction, that is, along the direction of arrow B3. Therefore, when the hybrid brake pad 1 and the mating member 6 are frictionally slid, the disadvantage that the first friction material 3 and the second friction material 4 are mixed due to the drag phenomenon of the friction material is as follows.
Is suppressed. Therefore, even if the hybrid brake pad 1 is used for a long period of time, it is possible to suppress a change in the friction characteristics of the hybrid brake pad 1.

In addition, according to the present embodiment, the first friction material 3 having a low friction coefficient preferentially rubs against the mating material 6, so that the first friction material 3 has a low friction coefficient.
If the friction coefficient μ _L of the friction material 3 is made extremely small, the wear of the mating material 6 can be made extremely small, which is advantageous for reducing and avoiding uneven wear of the mating material 6. Therefore, it is advantageous in reducing and avoiding abnormal vibration caused by uneven wear of the counterpart material 6. As another example, a pad having a structure in which the friction material 3 having a low friction coefficient does not protrude in a normal state and is on the same surface as the friction material 4 having a high friction coefficient can be used. In this case, the frictional material 4 (having a high coefficient of friction), which is a portion having a large compressive modulus, is more likely to share the compressive load than the friction material 3, which is a portion having a small compression modulus, and therefore the friction coefficient is high. The "effectiveness" of the brake is secured.

(Embodiment 2) FIG. 4 shows Embodiment 2 according to the present invention.
Shown in This example has basically the same configuration as that of the first exemplary embodiment, and has the same operation and effect. However, in this example, a soft cushion portion 7 is provided on the first friction material 3 having a low friction coefficient. Therefore, it is advantageous to reduce the compression elastic modulus E _L of the first friction material 3. Therefore, in this example, when compressed by the mating member 6, the first friction material 3 is easily pulled in. The cushion portion 7 may be provided between the first friction material 3 and the back metal 2, or may be embedded inside the first friction material 3. In the example shown in FIG. 4, the cushion portion 7 is in a lump shape, but is not limited thereto and may be in a granular shape.

(Embodiment 3) FIG. 5 shows Embodiment 3 according to the present invention.
And FIG. This example has basically the same configuration as that of the first embodiment, and has the same operation and effect. In this example, the brake pad 1 is substantially coaxial with a first friction material 3 having a low friction coefficient, a second friction material 4 having a high friction coefficient, and a boundary area between the first friction material 3 and the second friction material 4. It is configured in combination with the arranged arc-shaped third friction material 8.

In this embodiment, the friction coefficient μ _L of the first friction material 3 is the same as the friction coefficient μ of the second friction material 4 as in the first embodiment.
It is smaller than _{H (μ L <μ H)} . The compression elastic modulus E _L of the first friction material 3 is equal to the compression elastic modulus E _L of the second friction material 4.
_H (E _L <E _H ). The wear rate W _L of the first friction member 3 is smaller than the wear rate W _H of the second friction member _{4 (W L <W H)} .

Further, as described above, the friction coefficient of the third friction material 8
μ_MIs the friction coefficient μ of the first friction material 3 _LAnd the second friction material 4
Friction coefficient μ_HIt is in between. (Μ_L<Μ_M<Μ
_H). Also, the compression elastic modulus E of the third friction material 8_MIs the first friction
Compressive modulus E of material 3_LAnd the compression modulus E of the second friction material 4_H
(E_L<E_M<E_H). Also
Wear rate W of third friction material 8_MIs the wear rate W of the first friction material 3
_LAnd the wear rate W of the second friction material 4_HIt is in between.
(W_L<W_M<W_H).

According to this embodiment, as shown in FIG.
The first friction material 3 having a low friction coefficient projects ΔL1 more than the second friction material 4 and the third friction material 8 having a high friction coefficient. Further, as shown in FIG. 6B, the third friction material 8 may project from the second friction material 4 by ΔL2, and the first friction material 3 may project from the second friction material 4 by ΔL1. it can. In this case, ΔL2 is smaller than ΔL1 (ΔL2 <ΔL
1).

(Test Example) As a test example, the characteristics of the friction coefficient μ were tested using the hybrid brake pad according to Example 1 described above. In this test example, the braking speed was 2
0 km / h, 50 km / h and 100 km / h. The test was performed according to JASO C406 (dynamometer test method). This test is a test for evaluating the service brake performance by simulating the actual use condition with a dynamometer using the same brake device as the actual vehicle.

FIG. 7 shows the test results. As can be understood from the characteristic line of FIG.
/ Cm ² ) has a low coefficient of friction. At the time of high pedal effort, that is, at the time of high load, the friction coefficient is set to be high.
It is apparent from this characteristic line that the first friction material 3 having a low friction coefficient mainly functions at the time of light pedaling force, and the second friction material 4 having a high friction coefficient mainly functions at the time of high pedaling force.

(Other Examples) According to the above-described embodiments, the first friction material 3, the second friction material 4, and the third friction material are divided. It is also possible to adopt a form that is continuously changed.

[0036]

According to the brake pad of the first aspect, at the time of light pedaling, the friction material having a small friction coefficient and advantageous for "reduction of squealing" preferentially rubs against the partner material. It is advantageous for “reduction”. Further, at the time of a high pedaling force in which the depression of the brake is increased, the friction material having a high friction coefficient comes to rub against the partner material, so that the "effectiveness" of the brake is secured. Therefore, it is possible to provide a structure that can easily achieve both “reduction of squeal” and “effectiveness”.

Further, according to the brake pad of the first aspect ,
A friction material having a small coefficient of friction has a small compression modulus and is easily pulled in at a high pedaling force. Therefore, at the time of high pedaling force, the friction material having a high friction coefficient easily rubs against the partner material. Therefore, it is possible to provide a structure that can more easily achieve both “reduction of squeal” at the time of light pedaling and “effectiveness” at the time of high pedaling. Furthermore, according to the brake pad of the first aspect , since the friction material having a low friction coefficient has a small wear rate, it is easy to maintain a structure in which the friction material having a low friction coefficient protrudes. Therefore, it is easier to achieve both "reduction of squeal" and "effectiveness".

Further, according to the brake pad of the second aspect ,
This is advantageous for reducing and avoiding the mixture of friction materials caused by drag due to friction. Therefore, it is advantageous for suppressing the fluctuation of the friction characteristics and can contribute to maintaining good friction characteristics for a long period of time.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a brake pad.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view of a state where the member is rubbing with a counterpart material.

FIG. 4 is a sectional view according to a second embodiment.

FIG. 5 is a configuration diagram of a brake pad according to a third embodiment.

FIG. 6 is a sectional view of a brake pad according to a third embodiment.

FIG. 7 is a graph showing a coefficient of friction.

[Explanation of symbols]

In the figure, 1 indicates a brake pad, 2 indicates a backing metal, 3 indicates a first friction material, and 4 indicates a second friction material.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-113039 (JP, A) JP-A-61-184232 (JP, A) JP-A-63-152734 (JP, A) 55525 (JP, U) Japanese Utility Model 63-66633 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16D 69/00 F16D 65/092

Claims (2)

(57) [Claims] 1. A friction material having a relatively low friction coefficient.
And a friction material with a relatively high friction coefficient.
A hybrid brake pad that has a relatively low friction coefficient protruding from other parts.
Therefore, a friction material with a relatively low friction coefficient has a relatively low friction coefficient.
A friction material having a smaller compression elastic modulus than a high friction material and a relatively low friction coefficient has a relatively low friction coefficient.
A hybrid brake pad characterized by a lower wear rate than high friction materials . 2. The hybrid according to claim 1, wherein the friction material having a relatively low friction coefficient and the friction material having a relatively high friction coefficient are arranged along the friction sliding direction. Brake pads.