JPS58193942A - Pad shim of disc brake - Google Patents

Abstract

PURPOSE:To prevent heat transmission to the piston side and improve radiation effect by constituting the pad shim from the layer of a good heat conductor making contact with the back surface of a pad and provided with a heat radiating part entending to the outer periphery of the pad and layer of a bad heat conductor making contact with a piston. CONSTITUTION:A friction pad 1 is constituted by a back metal 2, a pad lining 3, and a support 4 of the friction pad 1. On the back surface of the friction pad 1 is provided a pad shim comprising a first layer 6 made of a sheet of a good heat conductor such as a steel sheet or SUS which makes contact and engages with the back surface of the friction pad, and a second layer 8 made of a plate of a bad heat conductor such as a molded body of an asbestos system, a glass system or the like which makes contact and engages with the front surface of the piston 5. In the contact part between the first layer 7 and the second layer 8 is formed a partial outcot 7a for reducing the heat conductivity, and a large number of fins 7b are formed at the outer edge of the first layer 7, thus radiation of heat being carried out effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in pad shims used in disc brakes.

Generally speaking, it is known that disc brakes are superior to drum brakes in dissipating heat generated during brake operation.

However, since the rotor rotation is frictionally braked by applying friction knots to the rotor, it is inevitable that a considerable amount of heat will be generated, and depending on the brake operation conditions (for example, when the brakes are applied continuously), The contact area between the rotor and the friction rod becomes quite high temperature (more than 100 degrees Celsius), and if this is transmitted to the piston's hydraulic operating system, there is a possibility that it will cause a new vapor lock phenomenon, especially for JII friction rods. With the semi-metallic type brakes that are sometimes used, the risk of friction is greater because the rad itself is a good thermal conductor.For this reason, conventional disc brakes have been subject to abnormal noises during brake manufacture. It has also been proposed to use two pad shims arranged to prevent the generation of pistons (to prevent squealing), and to make these pad shims a thermally poor conductor to prevent heat transfer to the piston 911I.

However, even with this configuration, the thickness of the pad shim, which has thermal insulation properties, cannot be made too large without impairing its anti-squeal function, there are material limitations, and there is also a friction between the rotor and the pad shim. Since the heat generated at the frictional parts of the pads is not sufficiently dissipated, it is conceivable that heat builds up during continuous braking operations, leading to an increase in brake fluid temperature.

The present invention has been made in view of these points, and consists of a friction pad and a hydraulically actuated piston that applies a pressing force to the back surface of the friction pad. It has a two-layer laminate structure with a second layer consisting of a layer and a thermally poor conductor, and the first layer that comes into contact with the friction pad side forms a heat dissipation part to prevent heat transfer to the piston side. , which provides effective heat dissipation ability.

The present invention will be described below based on embodiments shown in the drawings.

Figures 1 to 3 show a first embodiment of the present invention, and in the figures, 1 is a friction pad, 2 is a nosepiece thereof,
3 is a pad lining.

The regret pad 1 is supported movably in the axial direction of the rotor by a support 4 disposed near the edge of the rotor (not shown).

5 is a piston that applies a pressing force in one direction to the rotor on the back surface of the umbrella pad 1, and the pressing force is generated by a hydraulic cylinder device (not shown).

Reference numeral 6 designates a pad shim of the present invention, which includes a first layer 7 made of a thin plate of a thermally good conductor (for example, a steel plate, 5US) that contacts and engages the back surface of the friction pad 1, and a thermally poor conductor that contacts and engages the front surface of the piston 5. 21-8, which is made of a plate of (for example, a molded body of BM thread or glass-based material).

Note that these 11-7 and second layer 8 can be easily attached with adhesive or the like, and the external shape of the second shield 8 only needs to transmit the entire pressing force from the piston to the friction pad 1. In this example, the second layer 8 is formed in the shape of a disk with a diameter slightly larger than the outer diameter of the piston 5, while the layer 11-7 has an outer shape that is a light amount larger in order to form a heat dissipation part to be described later. That's what I do. Furthermore, in this example, the contact portion of the first layer 7 with the 21m8 is partially cut out to reduce thermal conductivity.
In the pad shim 6 in this example, a large number of fins 7b, 7b, .
A heat dissipation section consisting of... is formed, thereby effectively dissipating the heat generated during braking into the air. In this example, the fins 7b, 7b... are bent at an angle of about 90 degrees with respect to the main body of the first layer 70 because they are bent at a right angle to the air flowing through the brake equipment when the vehicle is running. Increasing the area exposed to the air increases the heat dissipation effect.The installation of the brake device on the vehicle depends on the posture, but the brake device is usually set so that the top in Figure 1 is in the direction of vehicle travel. Considering that this is often the case, the configuration of this example is adopted.

4 to 6 show other embodiments of the present invention, in which the other configurations except for the shape of the first width 7' of the pad shim 6' are
Since it is similar to the figure, the same parts are given the same reference numerals and the explanation thereof is omitted.

In this example, the heat dissipation part 7b' formed by the outer edge portion in the left and right direction of the pad shim 6' in the figure 1117' is made as large as possible without colliding with other structural parts, and the heat dissipation area is increased. Therefore, a good heat dissipation effect can be obtained. In each of the above embodiments, the heat transmitted from the vc and l life pads 1 is efficiently dissipated into the air as shown by the arrows in FIG. 2 or 5. , the second layer 8.8' is on the piston 15 side.
It will be understood that the temperature of the brake M can be effectively prevented from increasing by acting as a heat insulator. According to experiments, even in a brake system in which a brake fluid temperature increase of approximately 105°C was observed when a conventional type pad shim, which is not the pad shim of the present invention, was installed,
It has been confirmed that when the pad shim of the present invention is worn on the skin, the liquid temperature only increases by 100° C. or less.

As stated above (1) The disc brake pad 7 according to the present invention has a relatively simple structure that suppresses the increase in brake fluid temperature that causes problems such as paper lock, and its usefulness is extremely high. It is.

[Brief explanation of drawings]

Drawings 1 to 3 are for explaining one embodiment of the pad shim of the present invention, in which Fig. 1 is a front view of the pad shim, Fig. 2 is a partially sectional plan view, and Fig. 3 is a side sectional view. Figures 4 to 6 illustrate pad shims of other embodiments, in which Figure 4 is a front view of the pad shim, Figure 5 is a plan view including a partial cross section, and Figure 6 is a side view of the pad shim. FIG. 1...Friction pad 2...Back metal 3...Pad lining 4...Support 5...Piston
6.6'...Pad shim 7.7'...1st layer
7a... Notch 7b... Fin 7b'
...Heat radiation part 8.8'...Second layer.

Claims (1)

[Claims] A pad shim is interposed between the rotor pressure contact friction pad of a disc brake and a hydraulically actuated piston that engages with the back surface of this friction pad to apply pressure contact force to the rotor. a first layer of a good thermal conductor,
The friction pad has a laminate structure consisting of a second layer of a thermally poor conductor that contacts and engages the piston, and the first layer has a heat dissipation portion extending outward from the rear contour of the friction pad. disc brake pad shim 0