JPH0130015B2 - - Google Patents

Description

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

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

However, since the rotor rotation is controlled frictionally by pressing a friction pad against the rotor,
It is unavoidable that a considerable amount of heat is 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 pad can reach a considerable temperature (over 100℃), which can cause the piston to heat up. If this is transmitted to the hydraulic actuation system, there is a risk of causing the so-called vapor lock phenomenon, and in particular, semi-metallic friction pads that are sometimes used as friction pads are susceptible to the above-mentioned danger because the friction pads themselves are good thermal conductors. becomes a big thing. For this reason, we use pad shims, which are placed to prevent abnormal noises (so-called squeal prevention) when the brakes are activated in conventional disc brakes, and these pad shims are made of a thermally poor conductor to prevent heat transfer to the piston side. A similar method has also been proposed.

However, even with this configuration, the thickness of the pad shim, which has heat insulating properties, cannot be increased too much so as not to impair its anti-squeal function, there are also material limitations, and there are also Since the heat generated at the frictional parts does not escape sufficiently, it is conceivable that heat accumulates during continuous braking operations, leading to an increase in brake fluid temperature.

The present invention has been made in view of these points, and includes a pad shim interposed between a friction pad and a hydraulically actuated piston that applies a pressing force to the back surface of the pad shim, which is made of a first layer made of a good thermal conductor and a heat conductor. The second layer has a two-layer laminate structure made of a 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 and effectively. It is designed to provide excellent heat dissipation ability.

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

1 to 3 show a first embodiment of the present invention. In the figures, 1 is a friction pad, and 2 is a friction pad.
is the secret money, and 3 is the pats lining. The friction 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).

Reference numeral 5 denotes a piston that applies a pressing force toward the rotor on the back surface of the friction pad 1, and the pressing force is generated by a hydraulic cylinder device (not shown).

6 is a pad shim of the present invention, and friction pad 1
A good thermal conductor (e.g. steel plate,
A first layer 7 made of a thin plate of SUS) and a piston 5
A second layer 8 is made of a plate of a thermally poor conductor (for example, an asbestos-based or glass-based molded body) that contacts and engages the front surface of the holder.

The first layer 7 and the second layer 8 may be attached with adhesive or the like, and the outer shape of the second layer 8 may be such that it transmits the pressing force from the piston to the friction pad 1. In this example, the second layer 8 is formed into a disk shape with a diameter slightly larger than the outer diameter of the piston 5,
On the other hand, the first layer 7 is designed to have a sufficiently large external shape for forming a heat dissipation section to be described later. Furthermore, in this example, the contact portion of the first layer 7 with the second layer 8 has partial notches 7a, 7b, . . . formed in order to reduce thermal conductivity.

In the pad shim 6 in this example, a heat dissipation section consisting of a large number of fins 7a, 7b, etc. is formed at the outer edge of the first layer 7 (left and right edges in the figure), thereby reducing heat generation during braking. It effectively dissipates heat into the air. Note that the fin 7 in this example
The reason why a, 7b... are bent at approximately 90 degrees with respect to the main body of the first layer 7 is to increase the area that comes into contact with the air at right angles to the air that flows through the brake equipment part when the vehicle is running. This is to enhance the heat dissipation effect, and it depends on the mounting position of the brake device on the vehicle, but considering that the brake device is usually set so that the upper side of Fig. 1 is in the direction of vehicle travel. The configuration of this example is adopted.

4 to 6 show other embodiments of the present invention, and the other configurations are the same as in FIG. 1 except for the shape of the first layer 7' of the pad shim 6'. The same reference numerals are given and the explanation thereof is omitted.

In this example, the heat dissipation part 7b' formed by the outer edge portion of the first layer 7' of the pad shim 6' in the left-right direction in the figure is made as large as possible within a range that does not conflict with other structural parts, and the heat dissipation area is increased. By increasing the size, a good heat dissipation effect can be obtained.

In each of the above embodiments, as shown by the arrows in FIG. 2 or 5, the heat transmitted from the friction pad 1 is efficiently radiated into the air, and the second layer 8, 8' is disposed on the piston 5 side. It will be understood that the brake fluid has a heat insulating effect and can effectively prevent a rise in brake fluid temperature. According to experiments, even in a brake system in which a brake fluid temperature increase of approximately 105°C was observed when a conventional pad shim other than the pad shim of the present invention was installed, the fluid temperature only increased by 100 °C or less when the pad shim of the present invention was installed. This has been confirmed.

As described above, the disc brake pad shim according to the present invention has a relatively simple structure that suppresses the increase in brake fluid temperature that causes problems such as vapor lock, and is extremely useful.

[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. It is a diagram. 4 to 6 illustrate pad shims of other embodiments, FIG. 4 is a front view of the pad shim, FIG. 5 is a plan view including a partial cross section,
FIG. 6 is a side sectional view. 1... Friction pad, 2... Back metal, 3... Pad lining, 4... Support, 5... Piston,
6, 6'...pad sim, 7, 7'...first layer, 7
a... Notch, 7b... Fin, 7b'... Heat dissipation part, 8, 8'... Second layer.

Claims (1)

[Claims] 1. A pad shim that is interposed between a rotor pressure contact friction pad of a disc brake and a hydraulically actuated piston that engages with the back surface of this friction pad and applies pressure contact force to the rotor, and contacts and engages with the pad back surface. It has a laminated structure consisting of a first layer of a thermally good conductor and 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. A disc brake pad shim that is characterized by: