AU2003203515A1 - Fluid cooled brake pad - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: Stan NOWAK Unit 3, 75 Erindale Road Balcatta, Western Australia, 6021 Australia Griffith Hack, Patent and Trade Mark Attorneys, 6th Floor, 256 Adelaide Terrace, Perth, Western Australia, 6000.

Standard Complete Specification for the invention entitled: FLUID COOLED BRAKE PAD The following is a full description of this invention, including the best method of performing it known to me:- Fluid Cooled Brake Pad Field of the Invention [0001] The present invention relates to a fluid cooled brake pad and, to a cooling element which may be retrofitted to a brake pad to form a fluid cooled brake pad.

Background of the Invention [0002] It is well known that the performance of brakes which comprise a brake lining bearing against a moving surface deteriorates as temperature of the brake increases. It is therefore desirable to cool brakes and brake pads to provide optimum performance. One well known way of cooling disc brake systems is to ventilate the surface (eg a disc brake rotor) against which the brake pads are applied. This can be achieved, for example in a disc brake system, by drilling a plurality of holes through the disc.

[0003] US patent No. 6,321,880 B2 (Nakamura) describes a detachable fluid cooling system for a bicycle (ie pushbike) disc brake. One of the problems according to Nakamura with prior art disc brake systems for bicycles is overheating of the actuating fluid causing vapour locks which can result in the brake actuating even though a brake lever is in a release position. To overcome this problem, Nakamura proposes a fluid cooling system which can be attached to a bicycle disc brake calliper. This system includes an attachment portion which detachably couples to an external surface of the brake calliper and a cooling portion coupled to the attachment portion forming a cooling unit to transfer heat from the brake calliper.

[0004] Throughout this specification the term "brake pad" is used generically to include a disc brake pad and a brake shoe, for example of the type incorporated in conventional vehicle drum brakes.

Object of the Invention [0005] It is an object of the present invention to provide an alternate arrangement and method for cooling a brake.

Summary of the Invention [0006] According to the present invention there is provided a cooling element for a brake pad provided with a brake lining and a backing plate supporting said brake lining, said cooling element including: a body having a first side configured for abutment with a surface of said backing plate opposite said brake lining; a fluid inlet; a fluid outlet; and, a fluid flow path providing fluid communication between said fluid inlet and said fluid outlet; whereby, in use, when said cooling element is coupled to said backing plate with said first side in abutment with said surface of said backing plate and a fluid supply is coupled to said fluid inlet, fluid flows into said body via said fluid inlet, through said fluid flow path and out by said fluid outlet, to cool said brake pad.

[0007] Preferably said fluid flow path opens onto said first side whereby fluid flowing through said fluid flow path is in direct contact with said backing plate.

[0008] Preferably said fluid flow path includes at least one channel or groove extending between said fluid inlet and said fluid outlet.

[0009] Preferably said fluid flow path includes a plurality of parallel connected channels or grooves extending between said fluid inlet and said fluid outlet.

[0010] Preferably said first side has a peripheral surface which extends about the first side and bounds a central region through which said fluid flow path extends, said peripheral surface configured to abut and seal against said surface of said backing plate.

[0011] In an alternate embodiment, said fluid flow path is formed internally of said body.

[0012] According to the present invention there is provided a fluid cooled brake pad assembly including: a brake lining; and, a backing element, said backing element having a first surface supporting said brake lining, a fluid inlet, a fluid outlet and a fluid flow path internal of said backing element providing fluid communication between said fluid inlet and said fluid outlet; whereby, in use, when a fluid supply is coupled to said fluid inlet, fluid flows into said backing element via said fluid inlet, through said fluid flow path and out via said fluid outlet, to cool said brake pad assembly.

[0013] According to the present invention there is provided a method for cooling a brake pad having a brake lining and a backing plate supporting said brake lining, said method including the steps of: attaching a body to a surface of said backing plate opposite said brake lining; providing a fluid flow path in or on said body; and, passing fluid through said fluid flow path.

[0014] Preferably said method includes a step of forming said fluid flow path to open onto a surface of said body in abutment with said surface of said backing plate so that fluid flowing through said fluid flow path is in direct contact with said backing plate.

Brief Description of the Drawines [0015] An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a plan view of a cooling element in accordance with the present invention; and, Figure 2 is a section view of a fluid cooled brake pad incorporating the element depicted in Figure 1.

Detailed Description of Preferred Embodiment [0016] Figure 1 depicts a cooling element 10 for a brake pad 12 depicted in Figure 2.

When the cooling element 10 is attached to the brake pad 12 the combination can be considered as a fluid cooled brake pad assembly 14. The brake pad 12 is of generally conventional construction and includes a brake lining 16 supported on a, typically metallic, backing plate 18. In the illustrated embodiment, the brake lining 16 is provided with a plurality of spiroidal grooves 20 which extend across the brake lining and open onto braking surface 22 of the brake pad 12. When incorporated in a wet brake system such grooves may provide additional cooling. However, embodiments of the present invention may be applied to any form of brake pad with or without surface grooves in the lining 16.

[0017] The cooling element 10 includes a body 24 having a first side 26 (which is shown face up in Figure 1) configured for abutment with a surface 28 of the backing plate 18 opposite the brake lining 16. The body 24 also includes a first fluid port which constitutes a fluid inlet and a second fluid port which forms a fluid outlet 32. A fluid flow path 34 is formed in the body 24 providing fluid communication between the fluid inlet 30 and the fluid outlet 32.

[0018] In this particular embodiment, the fluid flow path 34 is open on side 26 of the body 24. Accordingly, when the cooling element 10 is attached to the brake pad 12 with the side 26 in abutment with the surface 28, fluid flowing through the flow path 24 is in direct contact with the backing plate 18 and in thermal contact with the brake pad 12.

[0019] The fluid flow path 34 is in the form of a plurality of channels or grooves 36a- 36f (hereafter referred to collectively as "grooves 36") machined, cut or otherwise formed in the body 24. A peripheral surface 38 is provided on the first side 26 and bounds a central region 40 through which the fluid flow path 34 extends. When the cooling element 10 is coupled to the brake pad 12, it is the surface 38 which contacts the surface 28 and forms a seal to prevent the escape of fluid between the body 24 and the backing plate 18.

[0020] The grooves 36a-36d are connected in parallel in terms of fluid flow by groove 36e which extends from the fluid inlet 30, and by the groove 36f which extends from the fluid outlet 32. Thus, as fluid enters via the inlet 30, it is distributed via groove 36e into the grooves 36a-36d and then collected in groove 36f leading to the fluid outlet 32. In this way, there are four parallel flows of fluid across the brake pad 12.

[0021] A plurality of holes 42 are formed about the periphery of the body 24 passing through the surface 38. The holes 42 receive screws (not shown) for fastening the body 24 to the backing plate 18.

[0022] When the cooling element 10 is in use, a fluid circuit (not shown) is coupled to the inlet 30 and outlet 32. The circuit would include a reservoir of a cooling fluid (such as water or oil), a conduit extending from the reservoir to the fluid inlet 30, and a further conduit extending from the fluid outlet back to the reservoir. If desired, a radiator or other heat exchanger may be provided in the circuit. A pump is included in the circuit to circulate the fluid through the element 10 and reservoir/heat exchanger.

[0023] As the cooling element 10 is coupled directly to the brake pad 12, cooling is achieved at the very source of the heat generated in a braking system. This assists in maintaining a substantially constant co-efficient of friction. It also substantially prevents excessive heat transfer to the hydraulic fluid used for operating the brakes per se. This assists in reducing consumption of hydraulic brake fluid therefore avoiding the need to replenish brake fluid levels.

[0024] Now that an embodiment of the present invention has been described in detail, it will be apparent to those skilled in the relevant arts that numerous modifications and variations may be made without departing from the basic inventive concepts. For example, to assist in sealing of the element 10 to the backing plate 18, a gasket or sealing compound can be provided between the surfaces 28 and 38. Also, the fluid flow path 34 is depicted as being in the form of a plurality of parallel connected grooves or channels. However a single groove or channel may be provided in a variety of shapes and configurations including a serpentine or zig zag configuration between the fluid inlet 30 and outlet 32. In addition, while the fluid flow path described and depicted as opening onto the side 26 of the body 24 it may be disposed within the body 24. This can be achieved for example by drilling a plurality of parallel holes through the body and providing a manifold at opposite ends to provide fluid communication between the holes and the respective fluid inlet and outlet. Alternately, a sealing plate (not shown) can be fastened to side 26 to seal the fluid flow path 34 providing a modified cooling element in which a fluid flow path is disposed internally of the body. In embodiments where the fluid flow path is internal of the body 24, the resulting element can be considered as a backing element with an internal fluid flow path which can itself directly support a brake lining and therefore simultaneously act as a backing plate. Also while in the illustrated embodiment the brake pad 12 is represented in the form of a disc brake pad. The invention may be applied to brake shoes and other brake elements which comprise a brake lining and a supporting backing.

[0025] All such modification and variations are deemed to be within the scope of the present invention the nature of which is to be determined from the above description and the appended claims.

-8- Dated this 8 th day of April 2003 SAFE EFFECT PTY LTD By Its Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia

Claims (11)

1. A cooling element for a brake pad provided with a brake lining and a backing plate supporting said brake lining, said cooling element including: a body having a first side configured for abutment with a surface of said backing plate opposite said brake lining; a fluid inlet; a fluid outlet; and, a fluid flow path providing fluid communication between said fluid inlet and said fluid outlet; where, in use, when said cooling element is coupled to said backing plate with said first side in abutment with said surface of said backing plate and a fluid supply is coupled to said fluid inlet, fluid flows into said body via said fluid inlet, through said fluid flow path and out by said fluid outlet, to cool said brake pad.

2. The cooling element according to claim 1 wherein said fluid flow path is open on said first side whereby fluid flowing through said fluid flow path is in direct contact with backing plate.

3. The cooling element according to claim 1 or 2 wherein said fluid flow path includes at least one channel or groove extending between said fluid inlet and said fluid outlet.

4. The cooling element according to claim 1 or 2 wherein said fluid flow path includes a plurality of parallel connected channels or grooves extending between said fluid inlet and said fluid outlet.

The cooling element according to an one of claims 1-4 wherein said first side has a peripheral surface which extends about the first side and bounds a central region through which said fluid flow path extends, said peripheral surface configured to abut and seal against said surface of said backing plate.

6. The cooling element according to claim 1 wherein said fluid flow path is formed internally of said body.

7. A fluid cooled brake pad assembly including: a brake lining; and, a backing element, said backing element having a first surface supporting said brake lining, a fluid inlet, a fluid outlet and a fluid flow path internal of said backing element providing fluid communication between said fluid inlet and said fluid outlet; whereby, in use, when a fluid supply is coupled to said fluid inlet, fluid flows into said backing element via said fluid inlet, through said fluid flow path and out via said fluid outlet, to cool said brake pad assembly.

8. A method of cooling a brake pad having a brake lining and a backing plate supporting said brake lining, said method including the steps of: attaching a body to a surface of said backing plate opposite said brake lining; providing a fluid flow path in or on said body; and, passing fluid through said fluid flow path. -11-

9. The method according to claim 8 including a step of forming said fluid flow path to open onto a surface of said body in abutment with said surface of said backing plate so that fluid flowing through said fluid flow path is in direct contact with said backing plate.

A cooling element for a brake pad, said element substantially as herein described with reference to and as illustrated by the accompanying drawings.

11. A method of cooling a brake pad said method substantially as herein described with reference to and as illustrated by the accompanying drawings.