JPH0526268A - Brake disc and manufacture thereof - Google Patents

Abstract

PURPOSE:To reduce weight and to provide excellent wear resistance. CONSTITUTION:A brake disc itself is manufactured by effecting high pressure casting by using an aluminum alloy. Friction plates 16 are joined and coupled with respective tapered surfaces 27 and 28 on both sides through a friction welding method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a brake disc for a vehicle disc brake and a method for manufacturing the same.

[0002]

2. Description of the Related Art Disc brakes have a brake disc fixed to a wheel, and the friction surfaces of the brake disc are strongly clamped from both sides by piston brake pads held by calipers to generate a friction force. The brake is applied.

Such disc brakes have a stable braking force, and there is little reduction in the braking force due to braking from high speed and repeated braking, and are widely used especially for front brakes of passenger cars and light trucks.

[0004]

The conventional brake discs of such disc brakes use ordinary cast iron or ductile cast iron having good wear resistance. A brake disc made of such a material is heavy in weight and poor in thermal conductivity,
As the unsprung load increases, there is a problem in heat dissipation.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a brake disc which is lighter in weight and excellent in heat dissipation and a method for manufacturing the same. .

[0006]

A first aspect of the present invention is a friction plate made of cast alloy, which is made of a light alloy and is attached to a pressure contact surface with a brake pad.

A second aspect of the present invention is to manufacture a main body by solidifying molten metal of a light alloy under pressure, and connecting a cast iron friction plate to a pressure contact surface of a brake pad by a friction pressure welding method. .

[0008]

According to the first aspect of the invention, the brake disc is made of a light alloy having a friction plate made of cast iron attached to the pressure contact surface, and is provided at the tip of the piston of the brake cylinder of the caliper. The pad is pressed against the friction plate so as to be sandwiched from both sides, thereby generating a braking force.

According to the second aspect of the invention, the friction plate made of cast iron is joined to the body made of light alloy manufactured by pressure casting by the method of friction welding, whereby the friction plate is attached to the body. Will be available.

[0010]

1 and 2 show a brake disc according to a first embodiment of the present invention, which relates to a ventilated type brake disc 10. That is, the brake disc 10 has a structure in which two plate-shaped bodies are opposed to each other with a space 11 in between, and the plate-shaped bodies on both sides are separated by a plurality of radiation fins 12 radially extending in the space 11. It is structured so that it can be combined.

The brake disc 10 is provided with a cup-shaped hub 13 in the center thereof, and a circular center hole 14 is formed in the hub 13. Further, four to six bolt insertion holes 15 are formed in the hub 13 as needed, and the brake disc 10 is formed by bolts penetrating the bolt insertion holes 15.
Is fixed to the wheel. Further, friction plates 16 are attached to the end faces on both sides of the brake disc 10 on the outer peripheral side thereof. The friction plate 16 is firmly attached to the brake disc 10 by a friction welding method.

FIG. 1 shows a disc brake comprising such a brake disc 10, and a caliper 19 is arranged on the fixed side. And the caliper 19 has brake cylinders 20 on both sides thereof,
A piston 21 is slidably held in the brake cylinder 20. A pad 22 is fixed to the front end side of the piston 21, and the pad 22 presses the friction plate 16 of the brake disc 10 to generate a braking force.

The brake disc 10 according to this embodiment is
The body part is made of aluminum alloy, for example JISAC
8A is used to perform high pressure casting under a pressure of 500 to 1000 kgf / cm ² . The temperature during casting of the molten metal was set to 770 ° C., for example. The aluminum alloy disc is used to reduce the weight and improve the heat dissipation. Moreover, the pressure contact surface with the brake pad is made by joining friction plates of ordinary cast iron, ductile cast iron, or Ni-based austenitic cast iron (Niresist cast iron) to the end faces on both sides of the brake disc 10 by friction welding. The friction plate 16 on the disc 1
I am trying to bind to 0. Therefore, with such a structure, it is possible to obtain a strong bonding force and good thermal conductivity.

By using such a brake disc 10, it is possible to improve the braking performance and reduce the weight by 30% or more as compared with the conventional one.
Unsprung load is reduced. As a result, the dynamic performance of the vehicle is improved, and steering stability and fuel consumption can be reduced. Moreover, since the friction plate 16 is metallurgically bonded to the brake disc 10 by the friction welding method, a strong bonding force can be obtained.

FIG. 3 shows a method of joining the friction plate 16 to the brake disc 10 by friction welding, in which the chuck 25 holds the brake disc 10 which is cast under high pressure with an aluminum alloy.
In this case, the chuck 25 holds the hub 13 so as to receive it, and the taper surface 27 on the side opposite to the hub 13 is held.
Then, the friction plate 16 is gently pressed from right to left in the axial direction. At this time, the brake disc 10 is rotated at high speed by the chuck 25. Then the friction plate 1 that does not rotate
The friction surface becomes hot due to the friction between 6 and the tapered surface 27 of the rotating brake disc 10. Then, when the temperature becomes high, the pressing force is further increased and the upset is performed. The pressure of such an upset is 6-8kg.
/ Mm ² value.

The reason why the frictional pressure contact surface of the brake disc 10 is the tapered surface 27 is as follows. When the friction plate 16 is gently brought into contact with the brake disc 10, frictional heat is generated between the two. At this time, there is a difference in peripheral speed between the center side and the outer peripheral side, the peripheral side has a lower peripheral speed, and therefore the temperature becomes lower, and the outer peripheral side has a sharp temperature increase due to friction. Therefore, a temperature gradient is generated in the radial direction.

In order to eliminate such a temperature gradient, the pressure contact surface is tapered so that a large pressure is generated on the center side and a small pressure is generated on the outer peripheral side when the friction plate 16 is pressurized. To The difference in the pressing force offsets the difference in the peripheral speed. That is, since the peripheral speed is low on the center side, a high pressure is applied to generate a frictional force, while on the outer peripheral side, the applied pressure is weakened to generate a large amount of heat mainly due to the peripheral speed. Almost the same frictional heat is generated in the directions, and uniform pressure contact is performed. The angle of the tapered surface 27 with respect to the vertical surface may be 5 degrees or less, and is preferably set in the range of 3 to 0.2 degrees.

When the friction plate 16 is pressed against one taper surface 27, this brake disk 10 is then chucked by another chuck 26 as shown in FIG. 4, and the same taper surface 28 on the hub 13 side is attached. Friction plate 16 by method
Pressure contact. That is, while rotating the brake disc 10 by the chuck 26, the friction plate 16 is gently moved from the right side to the left side in the axial direction, and pressed against the tapered surface 28.
Finally, set up and press firmly. As a result, the brake disc 1 as shown in FIGS.
0 is produced.

As described above, according to the method shown in FIGS. 3 and 4, the gradient of the tapered surfaces 27 and 28 is utilized, and the difference in the peripheral speed in the radial direction is determined by the difference in the pressing force generated by the tapered surfaces 27 and 28. By canceling each other, the heating temperature is made to have a substantially uniform value along the radial direction, whereby the friction plate 16
Are more completely pressed and joined together. Therefore, the friction plate 16 will not fall off the tapered surfaces 27, 28.

In particular, the use of Ni-resist cast iron as the friction plate 16 improves wear resistance and corrosion resistance as compared with other cast irons. Further, such a Ni-resist friction plate 16 improves the thermal conductivity and improves the braking performance. Further, such a Niresist cast iron friction plate 16
Since the coefficient of thermal expansion is close to that of an aluminum alloy, it is possible to reduce the decrease in shearing force under pressure welding conditions and during use.

Next, the brake disc of the second embodiment will be described with reference to FIGS. This brake disc is a solid type without a space and a heat radiation fin in the middle, and the brake disc 1
The outer peripheral portion of 0 has an empty structure. Moreover, friction plates 16 are joined to both sides of the brake disc 10 by friction welding in the same manner as in the first embodiment.

Also in such a brake disc 10, as shown in FIG. 5, when the pistons 21 slidably held by the brake cylinders 20 on both sides of the caliper 19 are pressed by hydraulic pressure, the pads 22 are pushed from both sides. It comes to press-contact with the friction plate 16, and the braking force can be obtained by the frictional force at this time.

Although the present invention has been described above with reference to the illustrated embodiments, the present invention is not limited to these embodiments and various modifications can be made based on the technical idea of the present invention. For example, in the above-described embodiment, the brake disc 10 is formed by high pressure casting with an aluminum alloy, but instead of the aluminum alloy, another light alloy such as a magnesium alloy is used, and the high pressure casting is performed with such a light alloy. Then, the brake disc 10 may be manufactured.

[0024]

According to the first aspect of the present invention, the brake disc itself is made lighter because it is made of a light alloy and the friction plate made of cast iron is attached to the pressure contact surface with the brake pad. The unsprung load of the vehicle using such a large brake disc is reduced. Further, since the pressure contact surface with the brake pad is composed of a friction plate made of cast iron, it is possible to provide a brake disc having excellent wear resistance.

A second aspect of the invention is that a light alloy melt is solidified under pressure to manufacture a main body, and a friction plate made of cast iron is joined to a pressure contact surface with a brake pad by a friction pressure welding method. is there. Therefore, it is possible to obtain high strength with the main body solidified under pressure, and it is possible to firmly bond the friction plate made of cast iron to the main body by the friction welding method, and surely prevent the friction plate from falling off. Will be done.

[Brief description of drawings]

FIG. 1 is a side view in which a part of a brake disc of a first embodiment is cut away.

FIG. 2 is a front view in which a part of a brake disc is cut away.

FIG. 3 is a vertical sectional view showing pressure contact of a friction plate.

FIG. 4 is a vertical cross-sectional view showing pressure contact of a friction plate.

FIG. 5 is a side view in which a part of the brake disc of the second embodiment is cut away.

FIG. 6 is a front view of the brake disc.

[Explanation of symbols] 10 brake disc 11 space 12 radiation fins 13 hubs 14 Center hole 15 bolt insertion hole 16 friction plate 19 calipers 20 brake cylinder 21 pistons 22 pads 25,26 chuck 27, 28 Tapered surface

Claims (2)

[Claims] 1. A brake disc comprising a light alloy, and a friction plate made of cast iron is attached to a pressure contact surface with the brake pad. 2. A brake disc characterized in that a melt of light alloy is solidified under pressure to manufacture a main body, and a friction plate made of cast iron is coupled to a pressure contact surface of a brake pad by a friction pressure welding method. Production method.