Wheel assembly for drum brake

Field of the Invention:

The present invention relates to "Wheel assembly for drum brake" and more particularly to hub design for the wheel having arms.

Background of the Invention:

Brakes are important safety components. Both disc and drum brake work on the same principle: friction and heat. When resistance or friction is applied to a turning wheel, the vehicle's brake system causes the wheels to decelerate and finally stop. During this process heat is generated causing the brake temperature to rise. The factors, which determine the vehicle deceleration, are vehicle weight, braking force, coefficient of friction, and pressure distribution over the braking surface area. Apart from these, another important factor is how efficiently the brake system converts the wheel motion into heat and subsequently, how quickly this heat is dissipated from the brake components. Disc brake components are fully exposed to the atmosphere and hence heat removal is efficient. On the other hand, drum brake components are fully enclosed inside the brake assembly. This may result in comparatively higher temperature vis-a-vis disc brake system under same braking conditions. High temperature of the drum brake shoe may cause brake fade and eventually lose effectiveness. Fading is the result of too much heat build-up within the drum. Hence, the drum brakes can only operate as long they can absorb heat generated by kinetic energy lost due to decelerating the wheels. Once the brake components are themselves become saturated with heat, they lose the ability to stop a vehicle.

At high temperatures, other components of the brake system undergo higher thermal expansion. Since the geometry of the drum brake is more complicated than the disc brake, maintaining the component dimensions at high temperature within the desirable limit is very critical. Thermal expansion of a component beyond a certain limit may interfere with the other neighboring components. This may result in the thermal seizure or locking of the drum brake. This, in turn, can result in further rise in temperature of the system and consequently, it can trigger the failure of other components.

A high rate of heat generation inside the drum brakes and low dissipation of heat to the ambient air leads to failures like brake fading, squeal noise, ineffective brake, and reduce life of liner & drum.

Therefore the challenge is to design a brake system that would dissipate heat generated inside the drum as quickly as possible to the ambient.

Designs have been developed for brake drum to dissipate heat from it wherein they provide facial ribs or teeth like protrusions on the brake hub. In this kind of design, cross flow of air will not happen. Hence, cooling effectiveness of the facial ribs will be less. These ribs or teeth are connected to the hub only. Hence, conduction heat transfer will be ineffective.

Therefore, it is an object of the present invention to provide an improved wheel assembly for drum brake.
Summary of the Invention:

The present invention has been achieved in an effort to bring out a solution, which overcomes the above mentioned problems.

Accordingly, an object of the present invention is to provide drum brake with heat sink between the arms of wheels of a vehicle.

Another object of the present invention is to provide a heat sink for drum brake which connects the arms and hub.

Another object of the present invention is to provide a heat sink for drum brake which can also be used to mount disc brake.

Yet another object of the present invention is to provide a heat sink for drum brake which reduces the temperature of the brake liner by preferably 50 degree centigrade.

Further object of the present invention is to provide a heat sink for drum brake which increases the life of the drum brake.

Another object of the present invention is to provide a heat sink for a drum brake which drastically decreases the structural deformation at the arm root.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Brief Description of the Drawings:

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein Figure. 1 is a conventional two wheeled scooter type vehicle.

FIG. 2 shows isometric view of the heat sink with the wheel according to the present invention.

FIG. 3 shows the different views of the heat sink according to the present invention.

Detail description of the Drawings:

The present invention now will be described more fully hereinafter with different embodiments. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather those embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the invention to those skilled in the art.

The subject matter of present invention relates to heat sink for drum brake of a vehicle and more particularly for wheels designed with arms.

The present invention is illustrated with the help of a scooter type motorcycle. Referring to figure 1, a reference number 1 denotes a front wheel, 2 denotes a front fork, 3 denotes a front fender, 4 denotes a front cover, 5 denotes a leg shield made of resin or metal, 6 denotes a handle bar cover, 7 denotes a headlight, 8 denotes a handle bar, 17 denotes a rear fender and 18 denotes tail lamp.

The center of the body forms a low floor board 9 for functioning as a part for putting feet and a under cowl 10 which is located below the rider's seat and covers at least a part of the engine, The under cowl is made up of metal or resin. The under cowl is hinged to the seat 11. A utility box 12 opens from the rear end to hinged portion. The utility box 12 is provided under the seat extending longitudinally of a vehicle body and the inside of the utility box has a large capacity so that a large article can be housed. A main frame 14 extended along the center of the body before and behind and made of a metallic pipe and is provided under the floor board 9. A swing type power unit 13 is coupled to the rear end of the main frame 14.

A rear wheel 15 is supported on one side of the rear end of the swing type power unit 13. The swing type power unit 13 is suspended in the rear of a body frame.

The side covers 16 both on left and right sides, covers the utility box 12 and other parts of the vehicle, thereby providing a good appearance to the vehicle.

Referring to figure 2, according to one aspect of the present invention heat sink 201 is provided between the arms 202 of the wheels. The said heat sink 201 is designed in such a way that it connects the two arms 202 and brake hub 203. Referring to figure 3, at least one conductive face 201 (a) extending from the hub 203 and connecting at least one arm 202 and a plurality of convective faces 201 (b) extending from the said conductive faces 201 (a). Heat generated below the hub 203 i.e. inside the drum liner can quickly conduct to the arms via the conductive face 201 (a) attached to the hub 203. With increase in surface area of the heat sink 201 and appropriate connection with hub 203, both convection and conduction heat transfer becomes efficient. Further, since the said heat sink 201 connects the arms 202 of the wheel, it helps in reducing the structural deformation.

The surface connected the hub 203 conducts the heat from the hub 203 and transfers it to the surface connected to the arms 202. Arms 202 are generally at lower temperature than hub 203. Due to high temperature gradient between the hub 203 and arms 202, heat sinks 201 works efficiently for heat transfer.

In another aspect of the present invention, the heat sink 201 connects to at least one arm 202 of the wheel and the brake hub 203.

In another aspect of the present invention, the heat sink 201 design on the drum brake which connects the hub 203 and the arms 202 can serve as the mounting location for disc brake (shown in figure 3).

The shape and size of the heat sink can vary and can be of any shape and size. The said heat sink can connect the arm of the wheel at any location along its length.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims.

We Claim:

1. In a wheel assembly a heat sink for drum brake comprising:

a hub housing the drum brake;

a plurality of arms connecting the hub with a rim for supporting the tyre;

at least one conductive face extending from the hub and connecting at least one arm; and

a plurality of convective faces extending from the said conductive faces;

wherein the said conductive face of the heat sink can connect to the arm at any location along the arm's length.

2. The heat sink for drum brake as claimed in claim 1, wherein the said wheel is preferably alloy wheel.

3. The heat sink for drum brake as claimed in claim 1, wherein the said heat sink is also used to mount disc brake.