WO2000008351A1

WO2000008351A1 - Closed circuit disc brake cooling device

Info

Publication number: WO2000008351A1
Application number: PCT/IB1999/001366
Authority: WO
Inventors: Pierino Pistis
Original assignee: Pierino Pistis
Priority date: 1998-08-05
Filing date: 1999-08-02
Publication date: 2000-02-17
Also published as: IT1305853B1; ITCA980016A1; AU4924299A

Abstract

Disc brake cooling system comprising a disc (2) through which a serpentine channel (9) is passing from the input (13) to the output (14), both ports connected to the engine cooling system of a motor vehicle.

Description

CLOSED CIRCUIT DISC BRAKE COOLING DEVICE

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This invention refers to a braking system, in particular of a rotating disc type.

The further object of this invention is a motor vehicle implementing this braking system.

As known, a braking system is designed to develop a resisting action (force or torsion

moment) such as to oppose the motion of a mechanism or of complete vehicle.

The system is generally of a type capable of absorbing a resisting work of a sign opposite

to that of the engine work, and of dissipating such work in the form of heat.

The use of brakes of a drum type or of a rotating disc type is particularly widespread.

As known, a drum brake comprises a drum attached to a wheel hub, and two brakeshoes

capable of exerting a pressure against the drum.

As known, a rotating disc brake is constituted by a cast iron disc attached to a wheel hub,

by one or more sectors made of a friction material glued or riveted on small metal plates,

and a fixed element, known as caliper, straddling the rotating disc.

When operating the brake, the friction sections, supported and guided by the caliper , are

pressed against the two faces of the disc, usually by hydraulic control.

The braking action develops heat causing a temperature increase of the components of

the braking system, meaning of the rotating disc and the friction sections, or of the

brakeshoes and the drum.

This heat is dissipated by circulating air; however, whenever the brakes are subjected to

frequent use, the brake temperature may reach a high level. In this situation the brake is subject to rapid wear, and the brake's braking capacity may

drop considerably. Moreover, when the temperatures in question rise excessively, the

brake linings and the friction sectors tend to crystallize, with a consequent reduction of the braking capacity even after the brakes revert to their normal operating temperatures.

A further problem experienced in the brakes is the fact that when they are still "cold" and

the disc is wet, for instance due to rain, the aqueous layer deposited on the rotating disc

or drum impedes an adequate friction action, until after the brakes have been repeatedly

operated.

The man task of this invention is to eliminate at least a part of the mentioned

shortcomings. This task is solved in accordance with the prescriptions of the independent claims 1 and 4.

Moreover, special embodiments of the invention may be created in accordance with the prescriptions of the subordinate claims.

The following is to describe a few possible embodiments of thre invention, with reference to the attached drawings in which:

- Figure 1 shows a partially sectionalized rotating disc,

- Figure 2 shows a cross-section of a rotaing disc brake,

- Figure 3 shows an enlarged detail of the brake in Figure 3,

- Figure 4 shows an alternative embodiment of the invention, in a longitudinal cross- section,

- Figure 5 shows the same brake of Figure 4 in a front view. With reference to the mentioned figures, the brake disc, shown in the overall by the

number 1 , includes a rotating disc 2 and a pair of friction sectors 3 actuated by a caliper

4.

The characteristic of the rotating brake disc is to provide for suitable means to keep the

temperature of the rotating disc in the range from 80°C to 90°C.

The expert in the trade will immediately grasp the following advantages: the water layer depositing on the braking components evaporates immediately, thus allowing the brake to operate in an ideal manner.

By keeping the rotating disc constantly in a temperature range between 80 and 95°C, the

brake can also be stressed on a continuous basis, without affecting its braking

performance.

Moreover, additional means are preferably provided so as to keep the friction sectors 3 at a temperature in the range between 80°C and 90°C.

The reader experiended in the trade will immediately grasp that this characteristic allows

avoiding the harmful phenomena of crystallizing the friction sectors.

Both the first and the second type of the mentioned means are constituded by liquid-

based heat exchangers.

By utilizing a disc brake on a vehicle braking system, the liquid regulating the

temperatures may advantageously be the same which already provides the vehicle's engine cooling.

In this case the rotating discs of the braking system will be hydraulically connected to the

engine's cooling system. The person experienced in the trade will immediately grasp the advantages of such a

solution, and in particular its simplicity and low production cost.

According to the embodiment shown, the rotating disc 2 is internally crossed by

serpentine channel 9 passing the water originating from the engine's cooling system (not

shown).

The channel 9 provides for an inlet 13 and an outlet 14 communicating by appropriate

fittings 10.

In order to allow the rotation of the disc 2, the fittings 10 are joined to the disc 2 by

appropriate gaskets 11 , fitted in the example shown by lip seals 11 , which ensure the

hydraulic coupling between the stationary fittings 10 and the rotating disc 2; some centering plates 13 are also provided.

A person experienced in the trade may of course provide other technically equivalent

solutions.

In order to reduce the encumbrance of the hydraulic connection with the hydraulic disc the

fittings 10 may be arranged at the same distance from the rotating axis of the disc 2, as

shown in the Figures 4 and 5.

The fittings 10 may be connected to the engine's cooling system by check valves 5, so as

to prevent the cooling liquid from escaping when effecting the maintenance of the braking

system.

The examples shown refer to a rotating disc braking system, a person experienced in the

trade will however not find it difficult to apply the principles of the patent also to other

braking systems, such as to drum brakes.

Claims

1. A braking system characterized by providing means capable of keeping the

temperature of the rotating part between 80┬░C and 95┬░C.

2. A braking system according to the claim 1 , characterized in that it provides means

capable of maintaining the temperature of the friction sectors in a range between 80┬░C

and 95┬░C.

3. A braking system according to the claim 1 or 2, in which said means capable of

maintaining the temperature of the rotating part and/or of the friction sectors in a range

between 80┬░C and 95┬░C are liquid-based heat exchangers.

4. A braking system according to one of the claims from 1 to 3, in which said means are a rotating disc brake.

5. A braking system for motor vehicles with a liquid-cooled engine, characterized in that

they comprise at least one disc brake according to one of the claims from 1 to 4.

6. A braking system according to the claim 5, characterized in that it is hydraulically

connected to the engine cooling system.