JPS63654B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for fixing friction pads of a friction pad assembly used for brakes, clutches, etc. of vehicles, machines, etc. to a backing plate.

For example, in the conventional friction pad assembly for disc brakes, as shown in Figure 1, adhesive is applied to the surface of a bucking plate made by punching out a metal plate such as an iron plate, and the surface is coated with asbestos or other friction base material. Usually, a mixture of a binder such as a resin is sintered and molded by pressing while heating. However, when a brake is used, the bonded portion becomes high in temperature due to frictional heat, and furthermore, shearing force due to the braking force acting on the surface of the friction pad is applied, resulting in the disadvantage that the bonded portion may peel off. On the other hand, forming holes or recesses in the bucking plate and inserting friction material into the holes has been done, but although this is effective against shearing forces, it is not very effective against peeling. . There is also a method of fixing a pre-formed friction pad to the backing plate using rivets as shown in Figure 2, but as you can see from the drawing, the friction pad needs a hole through which the head of the rivet passes. The braking area is reduced by the cross-sectional area of this hole, and the life of the friction pad is shortened by the reduction in the volume of the friction pad. For example, in US Pat. No. 3,767,018 (October 23, 1973), a rivet having a head larger than the cross section of the shaft is fixed so that the backing plate and the head are spaced apart, and a friction material and a resin are bonded thereon. A method of press sintering a mixture of agents while heating is shown. However, with this method, it is difficult for the material to reach the area between the rivet head and the backing plate, and the press pressure is blocked by the head and insufficient pressure is applied to that area. The part does not become a sintered body with sufficient density, so the strength is weak and the part is damaged by vibration and shearing force during use, weakening the rivet's adhesion to the friction pad and causing the friction pad to peel off. There are drawbacks. In addition, when using rivets, the friction pad will wear out due to use, and if the head of the rivet comes into contact with the disk, abnormal wear of the disk will occur, so the thick part of the friction pad from the surface of the backing plate to the head of the rivet cannot be used. This has the disadvantage that the life of the friction pad is shortened accordingly.

The purpose of the present invention is to obtain a friction pad assembly in which the adhesion between the friction pad and the bucking plate is strengthened through the same process as the conventional heating sintering method by using a bucking plate with a special shape. It is something.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the external shape of a friction pad assembly for a disc brake according to an embodiment of the present invention, where 1 is a bucking plate and 2 is a friction pad. The backing plate used in the present invention has a large number of needle-like pins 3 on the surface of the backing plate, as shown in FIG. The needle-shaped pin 3 preferably has a root portion of about 0.5 to 1.0 millimeters, and one pin per 2 cm ² of pad area is sufficient, and it is preferable that it has a tapered shape.

The length of the pin used here needs to be as long as possible, especially the length that is longer than the remaining thickness when the friction material is worn down by the effective friction width. If the bucking plate is uneven, as is conventionally known, and the ratio of pin length/pin diameter is small, sufficient shear strength in the friction direction can be obtained between the friction material and the bucking plate during use. cannot obtain enough force to peel off the friction material and bucking plate. Therefore, the ratio of pin length/pin diameter must be 4 or more.

As mentioned above, when the length of the pin is long, when the friction material wears out, the pin inevitably comes into contact with the friction material. Therefore, it is essential that the pin does not damage the mating material when it comes into contact with the mating material. The occurrence of scratches caused by pins on the mating material is determined by the material and thickness of the pins.
In this case, it is a matter of course that the material of the pin must be softer than the mating material in order to prevent scratches.If it is softer than the mating material, it can be made of brass, etc., but it can be made of soft steel, which is the same as the bucking plate. But that's fine. However, in reality, when the mating material is cast iron (EC20), damage to the pin's mating material cannot be avoided even if a much softer brass pin is used.
The present inventors have discovered that when the same material is used, a larger pin diameter causes greater damage to the mating material, but a smaller pin diameter significantly reduces the degree of damage to the mating material. This is because abrasion particles are generated from the friction material during braking and are present at the friction interface between the mating material and the pin.If the diameter of the pin is small, the abrasion powder will spread to the contact surface between the mating material and the pin. If there is little direct contact between the two and the diameter of the pin is large, the abrasion powder will not be sufficiently diffused over the entire frictional interface and the direct metal contact between the mating material and the pin will increase, damaging the mating material. That is, the smaller the diameter of the pin, the better; as the diameter of the pin increases, the amount of abrasion powder per cross-sectional area of the pin decreases, reducing the ability to alleviate metal contact and damaging the mating material. In this case, the cross section of the pin is not necessarily limited to a circular shape, but mainly refers to the size (diameter) in the friction direction, but if this diameter exceeds approximately 1.5 mm, damage to the mating material will occur rapidly. growing.

The material of the pin should be soft such as brass, but it can also be made of mild steel like the bucking plate. A dense friction pad can be obtained by applying an adhesive to this backing plate, placing a mixture of friction base material and resin on it, heating it from above, and press-sintering it in the same manner as in the conventional method. In the friction pad assembly thus obtained, the surfaces of the pins on the bucking plate also contribute to adhesion, so the friction pads have a wider adhesion area and are much more strongly adhered than conventional ones, and the shearing force is absorbed by the pins. There is no possibility of peeling. In addition, even if the friction pad is worn and the tip of the pin comes into contact with the disk, the tip of the pin has a small cross-sectional area and the material of the pin is softer than the friction material, so it will not damage the friction material such as the disk. It can be used until the friction pad becomes thin and has a long life. Figure 3 shows the case of a friction pad assembly for a disc brake. In this case, since the disc is circular, if the pins are arranged horizontally in a straight line as shown, all the pins will be connected to the disc. The contact position is slightly shifted in the radial direction of the disk, which has the advantage of uniformly contacting the surface of the disk.

As can be seen from the above description, the present invention can be used not only for disc brakes but also for other friction members.
In this case, it is preferable to arrange the center of the pin on an inclined line so that when the friction member wears out and comes into contact with the brake plate, clutch plate, etc., the tip of the pin uniformly contacts the surfaces of those plates.

As explained in detail above, since the friction pad assembly of the present invention uses a bucking plate with needle-like pins on its surface, the friction pad and bucking plate will not separate from each other.
Moreover, it can be manufactured using the same method as conventional methods, and it has the characteristics that it can be used until the friction pad becomes thin.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a friction pad assembly for disc brakes, Figure 2 is a sectional view of a conventional friction pad assembly using rivets, and Figure 3 is a friction pad assembly used in the friction pad assembly of the present invention. It is a drawing showing an example of a backing plate. 1: Bucking plate, 2: Friction pad,
3: Needle pin.

Claims (1)

[Scope of Claims] 1. In a friction pad assembly, on the surface: (a) A material softer than the friction partner material and having a diameter of 1.0 mmφ or less on the surface where the friction material is worn by the effective amount (b) The effective amount of the friction pad A friction material is heat-pressed and sintered integrally with a backing plate having a large number of needle-shaped pins having a length of 4 or more and a pin length/pin diameter ratio of 4 or more. Friction butt assembly.