JPH0337658B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for forming a mounting hole for a return spring in a friction pad for a disc brake.

Prior Art In a disc brake, a pair of friction pads is pressed against a disc rotor that rotates together with the wheel, and the rotation of the wheel is suppressed by the frictional force generated between them.

By the way, in such disc brakes,
In order to avoid the undesirable phenomenon of so-called dragging, in which the friction pad continues to slide against the disc rotor even after the brake is released, a return spring is attached to the pad to return it to a non-active position.

Problem to be Solved by the Invention However, the mounting hole for the return spring is usually formed by drilling a hole in the back metal of the friction pad, and this mounting hole has a small diameter and is relatively long. (If the pad is short, the amount of insertion at the end will be small, making it difficult for the pad to return smoothly), which requires time and effort to process, and the problem is that the tool is expensive because it can break or wear out. was occurring.

On the other hand, for example, 378~
Using the method of forming a hollow part using a core as described on page 379, place a pin with the same cross-sectional shape as the mounting hole on the flat fixed surface of the backing metal, and then It is thought that the above problem can be solved by fixing the friction material and burying the pin in the friction material, and then pulling out the pin to form the mounting hole.

However, when the pin is placed on the flat fixing surface of the backing metal as described above, the pressure applied when fixing the friction material to the fixing surface of the backing metal causes the pin to be placed in the radial direction of the pin. In addition, there is a risk of bending in the direction along the fixation surface, and if the mounting hole is formed in a tilted or bent state, the workability of installing the return spring into the mounting hole may be impaired, or the return spring may be damaged after installation. The return spring may not be able to maintain a suitable posture. In addition, the mounting hole is formed in the friction material on the fixed surface of the backing metal, and the rod-shaped end of the return spring is installed at a position that protrudes relatively largely from the fixed surface of the backing metal into the friction material. There is a problem in that it is difficult to obtain a sufficient wear tolerance and therefore a sufficient life span of the friction pad.

The present invention was made against the background of the above circumstances, and its purpose is to easily and quickly form a mounting hole without requiring drilling for drilling, and to It is possible to form the return spring without tilting or bending, ensuring a suitable installation workability and installation posture, and also suppressing the protrusion of the end of the return spring into the friction material, thereby extending the life of the friction pad. An object of the present invention is to provide a method for forming a return spring mounting hole in a friction pad for a disc brake, which can sufficiently ensure the following.

Means for Solving the Problems In order to achieve the above object, the present invention provides a friction pad that has a reinforcing back metal and a friction material fixed to the metal back and is pressed against a disc rotor. A method of forming a mounting hole for inserting and mounting a rod-shaped end of a return spring that urges the return spring toward a position, the method comprising: (a) attaching the friction material of the backing metal to the fixing surface to which the friction material is to be fixed; , forming by press working a longitudinal recess for accommodating a pin having a cross-sectional shape similar to that of the mounting hole so as not to be relatively movable in the radial direction of the pin and in the direction along the fixing surface; (b) arranging the pin in the recess of the backing metal, and (c) fixing the friction material to the fixing surface of the backing metal on which the pin is placed, and attaching one end of the pin to the friction pad. and (d) pulling out the pin embedded in the friction pad.

Operation and Effects of the Invention In this way, a pin having the same cross-sectional shape as the mounting hole is arranged in the longitudinal recess formed on the fixed surface of the backing metal, and the friction material is fixed to the fixed surface of the backing metal. After embedding one end of the pin in the friction pad, the pin is pulled out to form an attachment hole for attaching the return spring to the friction pad. In this case, since the recess is formed by press working, the mounting hole can be formed more easily and quickly compared to the case where the mounting hole is formed by drilling, reducing the processing cost. This means that the tool will not break like it would otherwise.

Moreover, since the pin is disposed in the recess of the backing metal in the radial direction of the pin and cannot be moved relative to the fixed surface, the pin will not bend when the friction material is fixed to the fixed surface of the backing metal. It is possible to suitably prevent the mounting hole from being formed in an inclined or crooked state,
Thereby, it is possible to suitably ensure the workability of attaching the return spring to the attachment hole and the posture of the return spring after attachment.

In addition, since the mounting hole is recessed into the fixed surface of the backing metal, the rod-shaped end of the return spring inserted into the mounting hole is prevented from protruding relatively largely from the fixed surface of the backing metal into the friction material. could,
The wear tolerance of the friction material and the life of the friction pad can be sufficiently ensured.

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

FIG. 1 shows a general-shaped friction pad and a spring mounting hole formed therein. The friction pad 10 is composed of a metal reinforcing back metal 12 and a friction material 14, and when the brake is applied, The friction material 14 is pressed against a disc rotor that rotates together with the wheel, and rotation of the wheel is suppressed based on the frictional force generated between the two at this time.

A pair of sliding parts 16 protruding in the same direction are formed at both ends of the back plate 12 in the disk rotor rotation direction (left and right direction in the figure), and are slidably supported by a support member (not shown). It is becoming more and more common. On the other hand, the friction material 14 is formed by molding asbestos, a friction modifier, a binder, etc. at a predetermined temperature and a predetermined pressure, and is irremovably fixed to the back metal 12.

Near both left and right ends of the friction pad 10, there are a pair of return spring mounting holes 18 extending to approximately the center of the friction pad 10 in the height direction.
4 and the back plate 12, and a rod-shaped end of a return spring for returning the pad 10 pressed against the rotor to a non-operating position is inserted here.

Next, a specific method for forming the spring mounting hole 18 in the friction pad 10 will be described.

First, as shown in FIG. 2, a longitudinal recess 20 having a substantially semicircular cross section is formed on the friction material fixing surface side of the backing metal 12, which is formed into a predetermined shape, from the upper end of the backing metal 12 to the radius of the disc rotor. It is formed with a predetermined length toward the diagonally downward direction in FIG. 1, that is, toward the center of rotation of the disk rotor. This recess 20 can be easily formed by coining.
Next, as shown in FIG. 3, a pin 22, which is a metal bar member, is placed on the back metal 12 with approximately half of the pin 22 in the radial direction inserted into the recess 20 of the back metal 12. At this time, the pin 22 is accommodated in the recess 20 so as to be immovable relative to the pin 22 in its radial direction and in the direction along the fixed surface of the back metal 12. For example, as shown in FIG. 6, this pin 22 is molded with a rod-shaped portion 28 formed to have approximately the same diameter as the rod-shaped end of the return spring and a length equal to or longer than the required length of the mounting hole. A base 26 is provided with a groove 24 to facilitate the operation of pulling out the pin after molding.

Then, the pin 22 is heated under a predetermined pressure, at an appropriate temperature, and for a period of time so that the rod-shaped portion 28 of the pin 22, which is set half way into the recess 20 of the back metal 12, is embedded in the friction material 14. Friction material 14
While forming the friction material 1 and adhering it to the back metal 12.
4 to the back metal 12. Note that this friction material 14
The molding and bonding temperatures are generally selected within the range of 130 to 200°C, and the molding time is appropriately selected within the range of 5 to 30 minutes. FIG. 4 shows this process.

After the molding of the friction material 14 and the adhesion to the back metal 12 are completed, the pin 2 embedded in the friction pad 10 is removed.
2, a hollow hole remains as shown in FIG. 5, and this hollow hole becomes the return spring mounting hole 18 as it is.

In this way, the longitudinal recess 20 of the back metal 12
The return spring mounting hole is formed by simply placing the rod-shaped member 22 in the recess when molding the friction material 14 and adhering it to the back metal 12, and then pulling out the rod-shaped member. This eliminates the need for machining to form mounting holes after forming the friction pad, and eliminates wear and tear on tools such as drills, resulting in improved productivity and reduced processing costs.

In addition, since the pin 22 is disposed in the recess 20 of the back metal 12 in the radial direction of the pin 22 and in the direction along the fixed surface of the friction material 12 so that it cannot move relative to the pin 22, the friction against the fixed surface of the back metal 12 is prevented. When material 14 is fixed, pin 2
It is possible to suitably prevent the mounting hole 18 from being formed in a tilted or bent state due to the bending of the return spring 2, thereby improving the workability of installing the return spring into the mounting hole 18 and the return spring after installation. It is possible to maintain a suitable posture.

Furthermore, since the mounting hole 18 is recessed into the fixed surface of the backing metal 12, the rod-shaped end of the return spring inserted into the mounting hole 18 is prevented from protruding relatively largely from the fixed surface of the backing metal 12. As a result, the wear tolerance of the friction material 14 and the life of the friction pad 10 can be sufficiently ensured.

Note that the above description is merely an example of the present invention, and the present invention is also applicable to other aspects.

For example, the longitudinal recess 2 formed in the back metal 12
After extracting the pin 22 by increasing the radial depth of the recess so that the pin 22 is completely embedded within this recess, the mounting hole 18 is formed as shown in FIG. Good too.

Further, the direction in which the elongated recesses 20 are formed is not limited to the radial direction of the disc rotor, but may be parallel to each other or in directions that are spaced apart from each other as they approach the center of rotation of the disc rotor.

Further, the cross-sectional shape of the rod-shaped portion 28 of the pin 22 can be modified into a polygon or the like as necessary.

[Brief explanation of the drawing]

FIG. 1 is a front view of a friction pad formed by an example of the mounting hole forming method to which the present invention is applied. FIGS. 2 to 5 are plan views of essential parts showing each process for forming a mounting hole in the pad shown in FIG. 1. FIG. 6 is a front view of the pin used in the example of FIG. 1. FIG. 7 is a plan view of essential parts of a friction pad formed according to another application example of the present invention. 10: Friction pad, 12: Reinforcement back metal, 14: Friction material, 18: Spring mounting hole, 20: Recess, 2
2: Pin.

Claims (1)

[Claims] 1. A rod-shaped end of a return spring that urges a friction pad that has an auxiliary backing metal and a friction material fixed thereto and is pressed against a disc rotor toward a non-acting position. A method of forming a mounting hole for attaching the return spring by inserting a part into the fixing surface of the back metal to which the friction material is to be fixed,
forming, by press working, a longitudinal recess for accommodating a pin having a cross-sectional shape similar to that of the mounting hole so as not to be relatively movable in the radial direction of the pin and in the direction along the fixing surface; arranging the pin in a recess of the backing metal; fixing the friction material to the fixing surface of the backing metal on which the pin is placed, and embedding one end of the pin in the friction pad; A method for forming a return spring mounting hole in a friction pad for a disc brake, the method comprising the step of pulling out a pin embedded in the friction pad.