FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 200|
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION A Svstem And Method Of Brake Dust Removal From Drum Brakes
APPLICANT
TATA MOTORS LIMITED, an Indian company
Having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Badal G Bisen , D.S. Kad
Both are Indian Nationals
of TATA MOTORS LIMITED,
An Indian company having its registered office
at Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention.

FIELD OF INVENTION
The present invention relates to a system and method of brake dust removal from drum brakes and more particularly addresses the dust accumulation issue in brake assembly enclosure in a unique way. The application describes making a groove on trailing shoe of brake assembly in a specific way that during normal running and braking accumulates the dust and throws out of the enclosure through groove. The process of accumulation and disposing off is continuous and helps to reduce brake noise and improves the performance.
BACKGROUND OF INVENTION
Drum brakes are designed to convert kinetic energy into heat energy via the process of friction. In the friction process friction material rubs against the rotating drum and generates heat and friction material dust. This heat is intended to be further transferred to atmosphere. Nevertheless due to the design, the drums traps brake dust and it cannot escape out. This brake dust can cause poor braking and noises.
The brake dust in drum brake is a chronic issue as there is no escape route for the dust in disc brake. On usage brake friction lining wears off and constitute a fine powder like material, this fine dust remains in the enclosure constituted by the brake drum and brake assembly. In dynamic condition, the accumulated dust rotates with moving drum and due to centrifugal force takes the course to extreme radius, which is the drum friction surface. In such situation, if brakes are being applied, brake dust gets trapped between friction lining and drum friction surface which causes noise, reduction in performance, etc.
The consequence of friction dust inside the brake drum may worsen the retardation achieved for given amount of input pressure. If water or any such fluid gets between the friction surfaces and the drum, it acts as a lubricant and reduces braking efficiency. Further this fine dust during brake application traps between

friction pair and give rise to abnormal brake noises like squeal, squeak and brushing.
There are ways to remove the brake dust by providing the hole in the brake drum and blowing compressed air at regular interval or by removing the brake drum and cleaning, but these process is cumbersome and requires lot of mechanical work. Again these processes not being continuous process can only be performed while doing maintenance of the brake assembly. So, consistency of braking is not seen in such arrangements.
OBJECTS OF THE INVENTION
The main object of this invention is to obviate the aforementioned drawbacks.
Another object of this invention is to provide a system and a method used for brake dust removal from drum brake.
SUMMARY OF THE INVENTION
The embodiments herein provide a system and method for removal of dust in drum brakes in vehicles. The system comprises at least one groove inclined at an angle provided in a brake shoe to accumulate the brake dust. The groove is provided on said trailing shoe across the width of the friction surface to accumulate the dust generated during braking. The said brake dust traverses in downward direction in said back plate and is thrown out of the brake plate. According to present invention, the inclination angle of said groove can be varied based on said brake drum design. The groove start and end points are situated in the forward direction of rotation of brake drum.
The method according to present invention comprises steps of accumulating the dust generated during braking and non braking events in a groove provided in a trailing shoe of said brake drum, collecting said accumulated dust in said back plate and disposing said accumulated dust from said back plate to atmosphere. The

accumulated dust in said groove automatically falls down in to said back plate due to vibration or jerks during vehicle running. The above method is used inleading and trailing type brake shoe arrangement. In leading type of brake assembly said groove position on the fiction lining will start from back-plate mounting side and ends to the drum mounting side. In trailing type of brake assembly, the groove start point is at top position to the drum mounting side and end point is at bottom position on the friction lining of back plate mounting side.
BRIEF DESCRIPTION
Fig. 1 shows the brake drum assembly.
Fig. 2 shows a position of groove on trailing shoe of drum brake assembly.
Fig. 3 shows a schematic diagram of groove on brake lining of drum brake
assembly.
Fig. 4 shows a diagram illustrating a leading-leading type brake assembly.
DETAILED DESCRIPTION
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same,
Design constraint of brake drum traps the dust generated due to friction in the event of braking. To remove the dust automatically from the drum brake system, a groove is provided on a trailing shoe across the width of the friction surface starting from wheel cylinder end with 45° inclination. The angle of inclination of the groove can be varied according to the design of brake drum, however the angle will be almost 45°.
The basic principle of the dust removal process is that the groove accumulates the dust in braking and non braking events and then accumulated dust automatically falls down in to the back plate due to vibration or jerks. The vibrations or jerks are

usually generated automatically during vehicle running. Further this dust traverse from back plate surface to atmosphere. This back plate is basics structural part houses brake shoes, auto-adjuster mechanism, return & holding spring.
Now referring to FIG, \, the drum brake assembly comprises; brake drum which rotates with the wheel, a brake shoe 2 is mounted on a stationary brake plate 1. The brake shoes is pivoted at one end 3 and connected to the actuator 5 at the other end. When the brakes are applied, the pressurized break fluid acts on the pistons in the actuator (wheel cylinder) to push the brake shoes 2 outward against the drum. The friction linings are bonded on the brake shoe. The friction between the friction material on brake shoes and the brake drum creates a braking torque which slows down the vehicle. The return spring 4 pulls back the brake shoes away from the surface of the brake drum when the brakes are released.
Referring FIG. 2. The brake assembly back plate 1 anchors the brake shoe 2. The brake shoe lining has groove as shown in figure. The groove can have an inclination of 20° to 45 °. The groove shown in an embodiment is inclined at 45° angle. The groove is of 3mm width and 3 mm height. The width and height of the groove may vary according to the design of brake drum. The direction of rotation of drum is marked as forward. The groove accumulates the brake dust and throws away in to the back plate 1. which eventually falls down to the atmosphere.
Refereeing FIG. 3. The brake assembly back plate 1 anchors the brake shoe 2. The Brake shoe lining has at least one groove 3. The groove 3 accumulates the brake dust generated during braking due to friction and this dust traverse in the downward direction as shown as 4 in to the back plate 1.
The system can be used for leading/trailing type of brake shoe arrangement in the brake assembly. For leading type of brake assembly (FIG. 2), the groove position on the fiction lining will start from back-plate mounting side (bottom portion) and ends to the drum mounting side (top portion). The groove start and end points are situated in the forward direction of rotation of brake drum.

The system can be used for trailing type of brake shoe arrangement in the brake assembly. For trailing type of brake assembly (FIG. 3), the groove start point is at top position and end point is at bottom position. The bottom position is on the fiction lining is at back-plate mounting side and top position to the drum mounting side. The system can be used for brake assemblies having bonded lining on brake shoes.
Advantages of the present application are:
- Providing a system and a method for brake dust removal from drum brake.
- The system according to present invention is less expensive and can be manufactured easily.
- To operate the system and adopting such method there is no need of any external agent.
- The process of dust accumulation and disposing off is continuous and helps to reduce brake noise and improves the performance.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

WE CLAIM
1. A method for removal of dust in drum brakes in vehicles, comprising steps of;
accumulating the dust generated during braking and non braking events in a
groove provided in a trailing shoe of said drum brake;
collecting said accumulated dust in said back plate; and
disposing said accumulated dust from said back plate to atmosphere;
2. The method according to claim 1, wherein said accumulated dust in said groove automatically falls down in to said back plate due to vibration or jerks during vehicle running.
3. The method according to claim 1, wherein said is used for leading and trailing type brake shoe arrangement..
4. The method according to claim 3, wherein in leading type of brake assembly said groove position on the fiction lining will start from back-plate mounting side and ends to the drum mounting side.
5. The method according to claim 3, wherein in trailing type of brake assembly, the groove start point is at top position to the drum mounting side and end point is at bottom position on the friction lining of back plate mounting side.
6. A system for removal of dust in drum brakes, comprising;
at least one groove inclined at an angle provided in a brake shoe to accumulate brake dust; said brake dust traverses in downward direction in a back plate to dispose the accumulate dust to atmosphere.
7. The system according to claim 6, wherein in said groove is provided on said
trailing shoe across the width of the friction surface to accumulate the dust
generated during braking.

8. The system according to claim 6, wherein inclination angle of said groove can be varied based on said brake drum design.
9. The system according to claim 6, wherin the groove start and end points are situated in the forward direction of rotation of brake drum.