JPS62127531A - Disc braking device - Google Patents

Abstract

PURPOSE:To prevent a temperature rise in working fluid due to braking heat in a disc from occurring, by setting a brake pad pressing surface of a piston down to a blocking surface, while thermally spraying zirconia ceramics to an upper surface of an undercoating material for this blocking surface, and forming a covered layer thereon. CONSTITUTION:A piston 4 is of cup-shaped piston whose front part 4a opens, a cap 13 is insert in an opening part 4a, an undercoat 14 of heat resisting metallic material is thermally sprayed to a pressing surface 13a of a pad liner 7 of the cap 13, and a top coat 15, to which zirconia ceramics is thermally sprayed, is solidly formed on an upper surface of an undercoat 14. Since the zirconia ceramics is more excellent in a heat insulating effect than alumina- ceramics, braking heat produced in a disc 2 is intercepted by this covered layer whereby it is in no case transmitted to a hydraulic chamber 5, thus a temperature rise in working fluid is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a disc brake device used in a braking device for a vehicle or the like.

[Conventional technology]

In a disc brake device, the braking heat generated by the disc during the braking action is conducted to the piston, and in order to prevent the temperature of the hydraulic fluid from rising, the I! An insulator with low thermal conductivity is interposed as a heat insulating material between the pad @ plate of the Jim pad and the inner wall of the caliper and the piston, but in recent years, ceramics with excellent heat insulation properties have been used on the back of the pad back plate and on the piston. Some have a coating on the opposite side to increase the heat insulation effect.

[Problems to be solved by the invention] However, alumina-based ceramics are the mainstream of conventionally used ceramics, but alumina-based ceramics are relatively weak against thermal shock, and also suffer from thermal expansion with the base material of pistons, etc. There are differences in rates.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a disc brake device using ceramics that is resistant to thermal shock, has physical properties close to those of metal, and has excellent heat insulation properties.

[Means for solving problems]

In order to achieve the above object, the present invention disposes a pair of brake pads on both sides of a brake disc that rotates together with the wheel, and pushes the brake pads with a piston of a caliper to clamp the brake disc and perform fli11 operation. In a disc brake device for use, the brake pad pressing surface of the piston is formed as a closed surface, a heat-resistant base material is thermally sprayed on the closed surface, and zirconia-based ceramics are sprayed on the upper surface of the base material. It is characterized in that the covering layer is integrally formed.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

The caliper body 1 is made up of an action part 1a, a reaction part 1b, and a bridge part 1C that connects them.The bridge part 1C straddles the brake disc 2, and the caliper body 1 is provided in a bracket part so as to be movable in the disc axial direction by an opening pin. .

A cylinder 3 which is open on the brake disc 2 side is formed in the action portion 1a, and a piston 4 is fitted into the cylinder 3 in a fluid-tight and movable manner, thereby defining a hydraulic pressure chamber 5.

On the front surface of the piston 4, a brake pad 8 consisting of a pad back plate 7 to which a friction pad 6 is fixed is suspended by a hanger pin 9 so as to be movable in the disc axial direction, and a hanger pin 9 is attached to the reaction part 1b side of the caliper 1. A brake pad 12 consisting of a pad back plate 11 to which a friction pad 10 is fixedly attached to a friction pad 10 suspended from the brake pad 12 is arranged to clamp the brake disc 2 to perform a braking action.

The piston 4 is a screw-shaped screw with an open front surface 4a, and a cap 13 that closes the opening 4a is fitted into the opening 4a.
3a is thermally sprayed with an undercoat 14 made of a heat-resistant metal material that can withstand temperatures of, for example, 500°C.
A top coat 15 formed by thermally spraying zirconia ceramics is integrally formed on the upper surface of 4.

FIG. 2 shows another embodiment of the present invention, in which the piston 16 has an open side on the cylinder 3 side and a pad back plate pressing surface 16a.
An undercoat 14 made of a heat-resistant metal material is thermally sprayed on the pressing surface 16a in the same manner as in the above embodiment, and a topcoat 15 formed by thermally spraying zirconia ceramics on the upper surface of this undercoat 14 is integrally formed. It is formed.

FIG. 3 shows yet another embodiment, in which the piston 17 has a cross section H
A cap 18 serving as a closing surface is fitted onto the pad pressing surface, and an undercoat 14 and a topcoat 15 are thermally sprayed onto the cap 18.

A comparison between the zirconia ceramics used in the present invention and the conventionally used alumina ceramics is as follows.

In this way, the present invention forms a coating layer of zirconia ceramics which has a better heat insulating effect than alumina ceramics, so the braking heat generated in the disc 2 is blocked by the coating layer and transmitted to the hydraulic chamber 5. First, it prevents the temperature of the hydraulic fluid from rising.

〔Effect of the invention〕

As described above, the present invention provides a pair of brake pads on both sides of a brake disc that rotates together with the wheel, and presses the brake disc by pushing the brake pads with a piston of a caliper to perform a braking action. In the disc brake device, the brake pad pressing surface of the piston is formed as a closed surface, a heat-resistant base material is thermally sprayed on the closed surface, and a coating layer is formed by spraying zirconia-based ceramics on the upper surface of the base material. Since it is integrally formed, the surface area of the piston is increased, blood pressure is dispersed, and it is resistant to thermal shock.
In addition, a disc brake device can be obtained in which ceramics, which have physical properties similar to metals and have low thermal conductivity, is used as a heat insulating material.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a disc brake device to which an embodiment of the present invention is applied, Fig. 2 is a partially sectional perspective view showing another embodiment of the piston, and Fig. 3 is a sectional view of yet another embodiment of the piston. It is a partially sectional perspective view shown.

Claims (1)

[Claims] 1. A disc brake device in which a pair of brake pads are arranged on both sides of a brake disc that rotates together with the wheel, and the brake pads are pushed by a piston of a caliper to clamp the brake disc and perform a braking action, forming a brake pad pressing surface of the piston into a closed surface;
A disc brake device characterized in that a heat-resistant base material is thermally sprayed on the closed surface, and a coating layer formed by thermally spraying zirconia ceramics is integrally formed on the upper surface of the base material.