JPS6212918Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a friction pad for a disc brake, and particularly to a friction pad that can reduce heat fade during braking.

In disk brakes, friction pads are pressed against the disk rotor that rotates together with the wheel, and the rotation of the disk rotor is suppressed by the friction between the disk rotor and the friction pads. In such disk brakes, under harsh operating conditions such as high-speed braking or frequent braking, the temperature of the friction surfaces of the disk rotor and the friction pads generally rises, and the friction between them may be significantly reduced. This is called heat fade, and various preventive measures have been taken in the past. For example, the friction pads and disk rotor are made larger to increase the heat capacity of the friction parts, and a ventilated disk rotor is provided to increase the cooling capacity.

However, those disc brakes are
As the parts become larger and the structure becomes more complex,
In particular, there was a problem in that sufficient effects could not be obtained against rapid heat fade during high-speed braking.

The inventors of the present invention have conducted various studies based on the above circumstances, and have found that the decrease in the coefficient of friction between the disc rotor and the friction pad when the friction surfaces of the disc rotor and friction pad reach high temperatures is caused by the decomposition of the friction material. One of the major causes is the presence of high pressure between the disc rotor and the friction pad, and we have discovered that heat fade can be significantly reduced if the decomposed gas is properly removed. The present invention was made based on the above findings.

That is, the gist of the present invention is to provide a disk that rotates together with a wheel, comprising a backing metal in which a mold hole is formed, and a friction material that is fixed to the backing metal in a state that reaches the back surface of the backing metal through the molding hole. In a friction pad for a disc brake that suppresses the rotation of the disc rotor by pressing the rotor, the pad passes through the mold hole from the pressing surface of the friction material against the disc rotor to the back surface of the backing metal. This is because an exhaust hole is formed to exhaust gas generated between the friction material and the disc rotor.

Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

In FIG. 1, reference numeral 2 denotes a disc rotor that rotates together with a wheel (not shown), and on both sides there are friction pads 6, 8 supported by a torque member 4 so as to be movable in a direction parallel to the rotation axis of the disc rotor 2.
is installed.

The caliper 10 includes a cylinder part 12 and a reaction part 14 that face each other, and a bridge part 16 that connects them on one side. It is supported by the torque member 4 so as to be movable in a direction parallel to .

The cylinder portion 12 is provided with a cylinder bore 18 that opens toward the disk rotor 2 side.
0 is smoothed together. Therefore, as braking fluid pressure is supplied into the cylinder bore 18, the piston 20 is pushed out, and the friction pad 8 is pressed against one friction surface of the disc rotor 2, and the reaction force causes the caliper 10 to move. The friction pad 6 is pressed against the other friction surface of the disc rotor 2 by the reaction portion 14. Note that 22 is a seal ring with which the piston 20 performs a retracting action.

Here, the friction pads 6 and 8 are the disc rotor 2.
Friction materials 24 and 26 that come into sliding contact with the friction material 2
The friction pads 6, 8 are provided with plate-shaped backing metals 28, 30 to which the friction materials 24, 26 and the backing metals 28, 30 are fixed, respectively, and an exhaust hole 32 penetrating through the friction materials 24, 26 and the backing metals 28, 30 extends substantially over the entire friction surface of the friction pads 6, 8. They are formed so that they are located at an even density. That is, Figures 2 and 3
As shown in the figure, for example, in the friction pad 6, the friction material 24 is fixed to the backing metal 28 with a portion reaching the back surface of the backing metal 28 through six mold holes 34 formed in the backing metal 28. An exhaust hole 32 having a diameter smaller than the diameter of the mold hole 34 is formed at the center of each mold hole 34 so as to penetrate from the pressing surface of the friction material 24 to the back surface of the back metal 28.

Such exhaust holes 32 can be easily formed by machining after molding the friction material 24, but there is an advantage that they can be easily formed using a mold at the same time as molding the friction material 24. And such exhaust hole 3
In order to form the friction pad 2, there is no need to change any other parts and the conventional back metal having mold holes can be used as is, so the friction pad can be manufactured at low cost.

The effects of this embodiment will be explained below.

As the brake is operated and brake fluid pressure is supplied into the cylinder bore 18, the friction pads 6,
8 is pressed against the disc rotor 2 by the reaction section 14 and the piston 20. As a result, the rotational kinetic energy is consumed as thermal energy by the friction between the friction pads 6, 8 and the disc rotor 2, and the rotation of the disc rotor 2 is suppressed.

Under severe braking conditions, thermal energy is rapidly generated due to such friction, and the temperature of the pressing surfaces of the friction pads 6 and 8 and the friction surface of the disc rotor 2 rises sharply. So-called heat fade, in which the coefficient of friction between 6 and 8 and the disc rotor 2 is significantly reduced, is likely to occur.
Such heat fade is noticeable during high-speed braking, and according to the present inventor's experiments with conventional pads under such conditions, as shown in Figure 4, gas due to high temperature is caused by the pressing surface of the friction pad. It is recognized that a high pressure exists between the friction surface of the disc rotor and the friction surface of the disc rotor, and this lowers the coefficient of friction.

However, according to the friction pads 6 and 8 of this embodiment, even if decomposition gas is generated, it can be easily eliminated, so that heat fade can be largely eliminated.
That is, gas is thought to be generated between the pressing surfaces of the friction materials 24 and 26 and the friction surface of the disc rotor 2 due to the decomposition of the friction materials 24 and 26 due to high heat. Since a plurality of gases are arranged at approximately equal density on the friction surface of the friction pads 26 and the exhaust path is formed in the shortest possible length, the gas is immediately exhausted to the back surface of the back metals 28 and 30, and the pressure of the gas is significantly reduced. , 8 and the disc rotor 2 is maintained above a certain value. According to experiments conducted by the present inventor, as shown by the two-dot chain line in FIG. 5, results were obtained in which the line pressure was significantly lower than that of the conventional method (solid line). Here, the line pressure is the brake fluid pressure (Kg/cm ² ) required to obtain a constant braking effect (0.5G).

As described above, according to this embodiment, the gas generated between the friction pads 6, 8 and the disc rotor 2 is easily removed by the exhaust holes 32 formed in the friction pads 6, 8. Heat fade on disc brakes is largely eliminated. Therefore, even under severe braking conditions, the feeling of braking operation is maintained, and the safety of the vehicle can be improved. Since the exhaust hole 32 is formed through the mold hole 34, it can be formed very easily at the same time as the friction materials 24 and 26 are molded or by processing after molding. can be used as is.

Next, another embodiment of the present invention will be described.

In FIG. 6, the friction pad 35 has three exhaust holes 38, respectively, located inside the six mold holes 36 formed in the same manner as in the previous embodiment. It is formed to penetrate the friction material 40. In FIG. 7, the friction pad 42 has five exhaust holes 46 formed through the friction material 48 so as to be located inside the six mold holes 44, as described above. .

Therefore, according to these embodiments, the gas generated between the pressing surfaces of the friction pads 35 and 42 and the friction surface of the disc rotor 2 is discharged through the exhaust hole 38 or 4.
6, the air is more easily evacuated and heat fade is further improved. For example, with the friction pad 42 shown in FIG. 7, heat fade can be further eliminated as shown by the chain line in FIG.

Although the embodiments of the present invention have been described above based on the drawings, the present invention can also be applied to other aspects.

For example, the exhaust holes and the mold holes may be unevenly formed in positions of the friction pad where gas is likely to be generated.

Further, the friction pads having exhaust holes do not necessarily have to be used on both sides of the disc rotor, but may be used on one side where heat fade is more likely to occur.

As detailed above, according to the friction pad of the present invention, the gas generated between the friction pad and the disc rotor is easily removed through the exhaust hole formed in the friction pad, so that the heat fade of the disc brake is reduced. This will be largely eliminated. Furthermore, since the exhaust hole is formed through a mold hole, it can be formed very easily, and since a conventional back metal having a mold hole can be used, the friction pad can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing a disc brake including an embodiment of the present invention. 2 and 3 are a front view and a horizontal sectional view showing the embodiment of FIG. 1. FIG. FIG. 4 is a diagram showing the state of gas generation. FIG. 5 is a diagram illustrating the effect of the embodiment shown in FIG. 1. 6 and 7 are views corresponding to FIG. 2 showing other embodiments of the present invention, respectively. 2: Disc rotor, 6, 8, 35, 42: Friction pad, 24, 26: Friction material, 28, 30: Back metal, 32, 38, 46: Exhaust hole, 34, 36, 4
4: Mold hole.

Claims (1)

[Claims for Utility Model Registration] A vehicle comprising a back metal with a mold hole formed therein and a friction material fixed to the back metal while reaching the back surface of the back metal through the mold hole, and presses a disc rotor that rotates together with the wheel. In a friction pad for a disc brake that suppresses rotation of the disc rotor by A friction pad for a disc brake, characterized in that an exhaust hole is formed to exhaust gas generated between the pad and the disc rotor.