JPH033810B2 - - Google Patents

Description

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

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

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.

The mounting hole for the return spring has conventionally been formed by drilling into the backing metal of the pad, but this mounting hole has a small diameter and is relatively long (if it is short, it is difficult to insert the end of the spring). Because the amount is small, it is difficult for the pad to return smoothly), which requires time and effort to process, and the tools can break or wear out, resulting in the problem of expensive tools.

The present invention was developed against the background of the above circumstances, and its purpose is to eliminate the need for machining and tools for drilling holes,
Another 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 allows the mounting hole to be easily formed.

In order to achieve this object, the present invention includes a rod-shaped member on the fixing surface side of the backing metal that maintains its mechanical shape when the friction material is fixed to the backing metal and melts after reaching a predetermined temperature. , the rod-shaped member is arranged so that one end thereof is exposed to the outside, and in this state, the friction material is fixed to the backing metal, thereby embedding the rod-shaped member in the pad, and then firing the pad. The present invention is characterized in that a hollow hole is formed by melting the rod-shaped member, and the hollow hole is used as a mounting hole for the spring.

In this way, during the process of forming the friction pad, the mounting hole for mounting the return spring is formed at the same time, so that the effort of drilling after the friction pad is formed can be saved. Therefore, since no drilling tool is used, the cost required for the tool is reduced, the working time is shortened, and the machining cost is also reduced.

In order to further clarify such characteristics of the present invention, one application example thereof will be explained in detail below based on the drawings.

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

A pair of sliding parts 16 protruding in the same direction are formed at both ends of the back metal 12 in the rotor rotation direction (left and right directions in the figure), and are slidably supported by a support member (not shown) here. It's becoming like that. On the other hand, the friction material 14 is formed by molding asbestos, a friction modifier, a binder, etc. at a predetermined temperature and 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 spring mounting holes 18 that extend to approximately the center of the pad 10 in the height direction.
The rod-shaped end of the return spring for returning the pad 10 pressed against the rotor to the non-operating position is inserted therein.

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

First, as shown in FIG. 2, a longitudinal recess 20 with a substantially semicircular cross section is formed on the friction material fixing surface side of the backing metal 12 formed into a predetermined shape, from the upper end of the backing metal 12 diagonally downward in the figure. It is formed to a predetermined length toward the end. This recess 20 can be easily formed by coining. Next, this back metal 12 is set in a mold cavity for molding the friction material with its fixed surface side, that is, the side where the recess 20 is formed, facing upward. Then, within this elongated recess 20,
As shown in FIG. 3, a rod-shaped member 22 made of synthetic resin
is placed on the back metal 12 with approximately half of the radial direction inserted therein. This rod-shaped member 22 is thicker than the rod-shaped end of the return spring, and has a length equal to or longer than the required length of its mounting hole.

When the rod-shaped member 22 is set in the recess 20 of the back metal 12, the preformed friction material is filled into the mold cavity, and then the friction material 14 is molded and bonded to the back metal 12 at the same time under a predetermined pressure. (state shown in Figure 4). At this time, the recess 2 of the back metal 12
The rod-shaped member 22 set half way into the friction material 14 has the remaining half buried in the friction material 14. The molding and bonding temperature of this friction material 14 is generally in the range of 130 to 200°C, and the molding time is selected to be an appropriate temperature and time in the range of 5 to 30 minutes. The rod-shaped member 22 will not melt. A resin material that can withstand such conditions is selected in advance.

After forming and adhering the friction material 14 and embedding the rod-shaped member 22, it is fired at a predetermined temperature. The firing temperature is higher than the molding temperature of the friction material 14, and is appropriately selected in the range of 150 to 300°C. In addition, the firing time is generally between numbers, and at this point, the resin rod-shaped member 2 embedded in the pad 10
2 is melted. In other words, the rod-shaped member 22 is made of a material selected in advance that does not melt when the friction material 14 is molded or bonded, but only melts during the firing process under severe conditions. Therefore, the resin material is selected depending on the conditions of molding, adhesion, and firing, but in general, trifluoride resins, polyamide resins, polycarbonate resins, etc. can be used.

When the rod-shaped member 22 made of resin is melted and removed from the pad 10, a hollow hole remains there, and this hollow hole serves as the mounting hole 18 for mounting the return spring.

In this way, according to the above method, the longitudinal recess 20 is formed in the back metal 12, and the friction material 14 is formed.
By simply placing the rod-shaped member 22 in the recess 20 when bonding it to the back metal 12, the pad 1 that is subsequently formed
If 0 is fired, the rod-shaped member 22 will come out of the pad 10 at this stage and a hollow hole will be created there as a spring mounting hole, so there is no need for machining to form the mounting hole 18 after the pad is formed. This saves time and effort, and there is no wear and tear on tools such as drills, so productivity can be improved and machining costs can be reduced. In addition, the above-mentioned rod-shaped member is formed at the stage of forming and adhering the friction material.
It is possible to embed it within the pad in various ways different from those described above.

For example, the longitudinal recess 2 formed in the back metal 12
It is also possible to increase the depth in the radial direction of 0 so that the rod-shaped member 22 is completely embedded in this recess, or it is also possible to insert the friction material into the surface of the back metal 12 without forming any recess. By placing the rod-shaped member 22 on the fixed surface of the back metal 12 when molding and adhering the friction material 14, it is also possible to embed the entire rod member 22 in the friction material 14 at the same time as the molding and adhesion of the friction material 14. be.

When the rod-shaped member 22 is melted and removed during the pad firing stage, in the former case, the mounting hole 18 is formed on the side of the back metal 12, as shown in FIG. As shown in FIG. 7, it is formed on the side of the friction material 14. The former has the advantage that the rod-shaped member 22 is reliably positioned at a predetermined position when the friction material 14 is molded and bonded, and the latter has the advantage of eliminating the trouble of forming a recess in the back metal 12, making it easier to form holes. This has the advantage of further reducing the number of man-hours required.

In addition to resin, the above-mentioned rod-shaped member may be made of a low-melting point metal or other material that maintains its mechanical shape when the friction material is molded and bonded, and then melts during the firing of the pad.

Furthermore, in the above embodiment, a case was described in which the molding of the friction material and the adhesion to the backing metal were performed at the same time.
It is also possible to adhere the rod-shaped member to the friction pad and embed the rod-shaped member in the friction pad during the adhesion. However, in this case, it is necessary to form a recess into which a portion of the rod-shaped member is to be fitted during molding of the friction material, or to embed the rod-shaped member in the friction material during molding. In the latter case, by fixing the friction material in which the rod-shaped member is embedded to the back metal, the rod-shaped member is embedded in the pad.

[Brief explanation of the drawing]

FIG. 1 is a front view of a friction pad formed by an application example of the mounting hole forming method according to the present invention, and FIG.
5 through 5 are principal part plan views showing one process of forming the pad and attachment hole shown in FIG. 1. FIGS. 6 and 7 are plan views of main parts showing friction pads and mounting holes formed according to another application example of the present invention. 10: Friction pad, 12: Reinforcement back metal, 14: Friction material, 18: Spring mounting hole, 22: Rod-shaped member.

Claims (1)

[Scope of Claims] 1. A friction pad having a reinforcing back metal and a friction material fixed thereto and pressed against a disc rotor during braking, and a rod-shaped end of a return spring for returning the pad to a non-acting position. A method of forming a mounting hole for attaching the spring by inserting the friction material into the fixing surface side of the backing metal, while maintaining the mechanical shape and reaching a predetermined temperature when fixing the friction material to the backing metal. A rod-shaped member which is then melted is arranged so that one end of the rod-shaped member is exposed to the outside, and in this state, the friction material is fixed to the back metal, thereby embedding the rod-shaped member in the pad. Then, when firing the pad, a hollow hole is formed by melting the rod-shaped member, and the hollow hole is used as a mounting hole for the spring. How to form the return spring mounting hole.