JPH0547298Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to disc brakes, and particularly relates to a technique for preventing brake pad squeal.

``Prior art'' Brake pads installed on disc brakes exert braking force through frictional engagement force when clamping the disc, so during braking,
A noise called brake squeal occurs due to the vibration caused by the friction.

To deal with this brake squeal, conventionally, a shim plate such as a rubber plate was installed at the attachment point to the caliper on the back metal that makes up the brake pad together with the friction material that comes in contact with the disc, as a buffer material to restrict vibration transmission between the two. Alternatively, several combinations of measures have been taken to dampen the vibrations that cause squeal, such as forming slits or chamfering the friction material to lower the natural frequency of the brake pad.

``Problems to be solved by the invention'' However, the above countermeasures cannot be implemented without special dimensions or materials, such as cutting out a portion of the shim plate against the pressing surface of the hydraulic piston or claw when using a shim plate. Since components such as shim plates and rubber plates are required, and processing such as forming slits and chamfering is required in the friction material, an increase in cost is unavoidable. Furthermore, from the viewpoint of maintainability of the brake, it is desirable that consumable parts such as brake pads be as versatile as possible and do not require special processing.

This idea was proposed in view of the above circumstances.
By concentrating countermeasures such as those mentioned above on the brake pads as much as possible, and by using them alone or in combination with the above countermeasures without making the brake pads have a special shape, it is possible to effectively prevent squeal. The purpose of this invention is to obtain a disc brake that can achieve the desired performance.

``Means for Solving the Problems'' In order to achieve the above object, the present invention arranges friction materials fixed to the backing plate facing each other with a disk in between, and connects them to one leg of the caliper. In the disc brake, in which a braking force is applied to the disc by bringing the hydraulic piston and a pawl formed on the other leg of the caliper close to each other, a part of the friction material is attached to the back metal. There are four molded holes each for fitting, and these molded holes are arranged radially inward and outward of an arc whose center is the rotation center of the disk and whose radius is the distance to the center of the hydraulic piston. The two molded holes, which are distributed in halves and formed in the back metal of the friction material on the hydraulic piston side, are placed in positions where some of them overlap the pressing surface of the hydraulic piston, The four mold holes formed in the back metal of the friction material are arranged so that a portion thereof overlaps with the pressing surface of the claw portion.

``Function'' With the above configuration, simply by providing a molded hole in both the inner side (hydraulic piston side) backing metal and the outer side (caliper side) backing metal, the rigidity of both backing metals is reduced and the overall Therefore, it is recommended to provide a shim plate such as a rubber plate as a cushioning material on the backing plate where there is no mold hole as shown in the conventional technology, or to form slits or chamfer the friction material. Shows similar vibration damping effect.

In addition, since the positions of the mold holes provided in the pressing parts of the respective backing metals that are directly pressurized by the hydraulic piston and the pawl are different, the backing metals are deformed due to the reaction force during braking on the inner and outer sides. The conditions are different, and as a result, the vibration periods of the two backing metals are different and they interfere with each other.

Furthermore, the positions of the mold holes in the pressing parts of the inner backing metal and the outer backing metal are different, and
Because the structure is such that a part of the pressing surface overlaps the mold hole on both the inner and outer sides, the distribution of the pressing force applied to the friction material during braking becomes uneven, and unlike conventional notches, It can perform the same anti-squeal effect as a shim.

"Embodiment" Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

Reference numeral 1 is a caliper. A hydraulic piston 2 is provided on the inner side of the caliper 1 so as to be movable in the axial direction, and is operated by pressure applied to a hydraulic chamber 3. The sliding surface of the piston 2 is a ring. 4 and a sealing material 5 to seal the liquid. A back metal 7A of a brake pad 6A is attached to the tip of the piston 2 via a shim 8, and a friction material 9A is further attached to the back metal 7A. Further, on the opposite leg of the caliper 1 on which the piston 2 is provided, a claw portion 10 is provided facing the brake pad 6B made of a friction material 9B and a back metal 7B. Therefore, when the hydraulic piston 2 is pressurized, the friction material 9A is displaced toward the brake pad 6B that faces the brake pad 6B across the brake disc 11 and comes into contact with the brake pad 6B. Displaced in the opposite direction, the friction material 9B comes into contact with the disc 10, and the frictional force generated between these friction materials 9A, 9B and the brake disc 11 exerts a braking force.

There are four mold holes 12 in which the materials constituting the friction materials 9A and 9B are molded into, respectively, on the surfaces of the backing metals 7A and 7B constituting the brake pads 6A and 6B that are fixed to the friction materials 9A and 9B. They are formed at almost the same location on each.

The mold holes of the back metals 7A and 7B (labeled a to d. In the drawing, a and c are the holes on the outer side,
b, d indicate the holes on the inner side, a, c
The holes b and d also exist on the inner side, and the holes b and d also exist on the outer side. ) is the dashed line A in Figure 2.
Distributed inside and outside the effective radius of the brake disc 11 (distance from the center of rotation of the brake disc 11 to the center of the hydraulic piston 2) shown by
That is, two each of a and b are placed on the inside, and two of c and d are placed on the outside. Furthermore, in the back metal 7A of one brake pad 6A,
The inner mold holes a and b are aligned with the pressing surface of the hydraulic piston 2 (the part that presses directly in the thickness direction of the back metal), like the mold hole b shown in the right half of Fig. 2. On the back plate 7B of the other brake pad 6B, as shown in the mold holes a and c shown in the left half of FIG. It is arranged so that a part of it rests on the part that is directly pressed.

In both brake pads 6A and 6B of the disc brake configured as described above, the presence of the molded hole 12 lowers the rigidity of the back metals 7A and 7B compared to the case where the molded hole 12 does not exist. As a result, the natural frequency decreases.
In addition, since the manner in which the forces from the pressing surfaces of the piston 2 and the claw portion 10 act on the mold hole 12 on the inner and outer sides is different, there is a difference in the frequency of vibrations generated in the brake pads 6A and 6B on the inner and outer sides. In fact, they interfere with each other, and brake squeal is suppressed more than if the vibration periods were the same.

In addition, since the mold holes 12 are distributed on the inside and outside around the effective radius of the disk, the reaction force during braking is distributed and applied to these and deformed, so that the back plate 7A, The natural frequency of 7B can be lowered. Furthermore, since the portions of the mold hole 12 that are directly pressurized by the hydraulic piston 2 and the claw portion 10 are different on the inner side and the outer side, the back metal 7 due to the reaction force during braking on the inner side and the outer side
The deformed states of A and 7B are different. Furthermore, the pressing surface of the hydraulic piston is formed in the mold hole 12.
Since only a part of the pressing surface overlaps the mold hole 10 on both the hydraulic piston 2 side and the pawl part 10 side, the pressing force of the brake pads 9A and 9B becomes uneven, and the conventional cutting method It has the same anti-squeal effect as a shim with a chip.

In addition to the disc brake of the above embodiment that uses brake pads with molded holes arranged in a specific manner, the conventional method of preventing squeal using a shim with a cushioning material or a shim with a notch can be used. Of course, other measures may be used in combination.

"Effects of the Invention" As is clear from the above explanation, the present invention has the following effects.

Just by having a molded hole in both the inner side (hydraulic piston side) backing metal and the outer side (caliper side) backing metal, the rigidity of both backing metals decreases and the overall natural frequency decreases. , it exhibits a vibration damping effect similar to that shown in the prior art, in which a shim plate such as a rubber plate is provided as a cushioning material on a back metal without a mold hole, or in which a slit is formed or a chamfer is applied to a friction material.

Since the positions of the mold holes in the pressing parts of the respective backing metals that are directly pressurized by the hydraulic piston and the pawl are different, the deformation of the backing metals due to the reaction force during braking on the inner and outer sides is different. This makes it possible to make the vibration cycles of the two backing metals different and cause them to interfere.

The positions of the mold holes in the pressing parts of the inner and outer backing metals are different, and a part of the pressing surface overlaps the molding hole on both the inner and outer sides, which reduces friction during braking. The distribution of the pressing force applied to the material is non-uniform, making it possible to achieve the same squeal prevention effect as conventional shims with notches.

In general disc brakes, the parts that directly press the brake pad are different between the hydraulic piston and the pawl, so in actual use, you can simply use brake pads with the same planar arrangement of mold holes. The molded holes on the inner and outer sides are set in a predetermined positional relationship, making it possible to prevent squeal while preserving compatibility of the brake pads. This can be easily implemented by simply using a brake pad with molded holes in a specific arrangement, without requiring any new components or new assembly steps.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a longitudinal sectional view of a disc brake, and FIG. 2 is a front view of the right half taken in section from the disc surface. 1...Caliper, 2...Hydraulic piston, 6A,
6B...brake pads, 7A, 7B...back money,
9A, 9B...Friction material, 10...Claw portion, 11...
Brake disc, 12a, b, c, d...mold hole.

Claims (1)

[Scope of utility model registration request] Frictional materials fixed to the back metal are placed facing each other with the disk in between, and these are moved by a hydraulic piston provided on one leg of the caliper and a pawl formed on the other leg of the caliper. In the disc brake, in which a braking force is applied to the discs by bringing them close to each other, the back metal is provided with four molded holes each into which a part of the friction material is fitted, and these molded holes are They are arranged half inwardly and half outwardly in the radial direction of an arc whose radius is the center of rotation of the disk and the distance to the center of the hydraulic piston, and on the back plate of the friction material on the side of the hydraulic piston. The two molded holes formed are placed in positions that partially overlap the pressing surface of the hydraulic piston, and the four molded holes formed in the back metal of the friction material on the claw side are placed in positions that partially overlap the pressing surface of the hydraulic piston. A disc brake characterized by being placed in a position where a portion thereof overlaps the pressing surface.