DESC:FIELD OF THE INVENTION
[001] Present invention relates to a brake drum of a vehicle. More particularly, the present invention relates to the brake drum for a heavy vehicle.

BACKGROUND OF THE INVENTION
[002] Typically, vehicles are provided with a brake drum which is a vital component of a braking assembly of the vehicle. The brake drum plays a crucial role in slowing down or stopping the vehicle. The brake drum is used in conjunction with brake shoes to generate friction and facilitate the deceleration or stopping of the vehicle.
[003] Typically, the brake drum is made from cast iron or aluminum alloys. The cast iron material is chosen because of its durability and ability to dissipate heat effectively, while aluminum alloys are chosen because of their light weight and improved heat dissipation contributing to overall brake system efficiency.
[004] One of the major drawbacks of the brake drum is the construction. An outer body of the brake drum and its opening are not always perpendicular to each other due to which, an improper contact between the brake shoes and brake pads of the brake drum takes place. This leads to inefficiencies like non-uniform wear of the brake shoes and the brake pads, inefficient braking during heavy loads and overall decreased life of the brake pads.
[005] In view of the above, there is a need for a brake drum that mitigates one or more limitations stated above.

BRIEF DESCRIPTION OF DRAWINGS
[006] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 is a cross-section view of a brake drum, in accordance with an embodiment of the present invention.
Figure 2 is a cross-section view of the brake drum mounted on an axle spindle and connected to a wheel hub of the vehicle, in accordance with an embodiment of the present invention.

SUMMARY OF THE INVENTION
[007] In one aspect, a brake drum for a vehicle is disclosed. The brake drum comprises a hollow cylindrical body having a first end and a second end. A flat circumferential portion is provided between the first end and the second end. The flat circumferential portion is aligned parallelly to a central axis of the hollow cylindrical body, wherein the flat circumferential portion is adapted to maintain perpendicularity with a rim portion of the hollow cylindrical body.
[008] In an embodiment, the flat circumferential portion comprises an inner surface. The inner surface is adapted to engage with a brake pad of a brake assembly of the vehicle, wherein the inner surface is adapted to maintain perpendicularity with a face of the rim portion.
[009] In an embodiment, the flat circumferential portion comprises an outer surface and an inner surface. The outer surface is adapted to taper outwardly from the inner surface at a draft angle.
[010] In an embodiment, the draft angle between the outer surface and the inner surface is 2.5 degrees to 3 degrees.
[011] In an embodiment, the perpendicularly maintained between the hollow cylindrical body and the rim portion is within 0.05mm.
[012] In an embodiment, the hollow cylindrical body is casted.

DETAILED DESCRIPTION OF THE INVENTION
[013] Present invention relates to a brake drum of a vehicle. More particularly the present invention relates to the brake drum for a heavy vehicle. The brake drum is capable of being mounted on an axle of the vehicle through an axle spindle. The brake drum comprises a hollow cylindrical member having a first bore positioned towards a centre of the axle and a second bore oriented away from the axle. The brake drum is capable of accommodating a brake shoe topped with a brake pad liner. The brake pad liner on the brake shoe is capable of engaging with an internal surface of the brake drum, for braking of the vehicle. The brake drum is cast and machined such that, perpendicularity is maintained between an internal diameter of the first bore and face of the second bore. In an embodiment, the perpendicularity between the internal diameter of the first bore and the face of the second bore is within 0.05 mm. Such a construction ensures uniform contact of the brake shoe or the brake liner, thereby providing uniform and effective braking of the vehicle. Additionally, a draft angle or tapering is provided from the second bore to the first bore in order to increase thickness and consequently strength of the brake drum. In an embodiment, the draft angle of the brake drum is about 2.5 degrees to 3 degrees.
[014] Figure 1 is a cross-section view of a brake drum 100, in accordance with an embodiment of the present invention. The brake drum 100 in the present embodiment is provided for a vehicle (not shown), such as a trailer or a semi-trailer. The brake drum 100 comprises a hollow cylindrical body 102 having a first end 102a and a second end 102b. The first end 102a is provided with a first bore 104, while the second end 102b is provided with a second bore 106. The first bore 104 and the second bore 106 are concentric with one another along a central axis A-A’ of the hollow cylindrical body 102. In the present embodiment, the first bore 104 is provided with a bore of a larger diameter than that of the second bore 106.
[015] Referring to Figure 2 in conjunction with Figure 1, the brake drum 100 mounted on an axle spindle 132 and connected to a wheel hub 110 of the vehicle is depicted. Around circumference of the second bore 106, a rim portion 112 is provided. The rim portion 112 is oriented perpendicularly to the central axis A-A’ of the hollow cylindrical body 102. The rim portion 112 is provided with plurality of holes 114. The plurality of holes 114 are adapted to align with holes (not shown) provided to a flange 112 of the wheel hub 110. The plurality of holes 114 (shown in Figure 1) and the holes provided to the flange 112 are fastened through a fastener 116 (shown in Figure 2), thereby mounting the brake drum 100 to the wheel hub 110. As such, the brake drum 100 is adapted to rotate along with the wheel hub 110 during riding of the vehicle. In an embodiment, the brake drum 100 is mounted to the wheel hub 110 such that, the first bore 104 is positioned towards a centre of the axle 108 (or inboard side of vehicle) and the second bore 106 is positioned away from the axle 108 of the vehicle (or outboard side of vehicle).
[016] Further, a flat circumferential portion 102c extends from the rim portion 112 through an intermittent connecting portion 124. The intermittent connecting portion 124 may be provided with a contoured surface with one or more curved surfaces. The flat circumferential portion 102c is aligned parallelly to the central axis A-A’. In an embodiment, the thickness of the flat circumferential portion 102c increases or tapers from the first side 102a to the second side 102b. In other words, a draft angle 126 is provided to the flat circumferential portion 102c of the hollow cylindrical body 102. The tapering or the draft angle 126 increases thickness of the brake drum 100, thereby enhancing strength of the brake drum (100). In an embodiment, the draft angle 126 is 2.5 degrees to about 3 degrees.
[017] Furthermore, the hollow cylindrical body 102 is adapted to enclose a brake assembly (not shown) of the vehicle. The brake assembly comprises a brake liner 118 over which a brake pad 120 is provided. In the present embodiment, the brake liner 118 and the brake pad 120 are positioned to engage an inner surface 122 of the flat circumferential portion 102c of the hollow cylindrical body 102. The brake liner 118 is operable through a brake pedal (not shown) for enabling engagement between the brake pad 118 and an inner surface 122 of the hollow cylindrical body 102.
[018] In an embodiment, a perpendicularity is maintained between the inner surface 122 and a face 128 of the rim portion 112. In other words, perpendicularly is maintained between an inner surface 122 of the flat circumferential portion 102c and face 128 of the second bore 106. In an embodiment, the perpendicularity is within 0.05 mm. Such a construction ensures uniform contact of the brake shoe or brake liner, thereby providing uniform and effective braking of the vehicle.
[019] Advantageously, due to perpendicularity of the brake drum, the contact of the brake pad with the inner surface of the brake drum is uniform and effective braking thereby leading to a longer life of the brake pads. Further, due to the draft angle, the wall of the brake drum is thicker which adds to the strength of the brake drum thereby the heat generated while braking under heavy load has less effect on the brake drum.
[020] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since the modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to the person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.

Reference numerals
100 – Brake drum
102 – Hollow cylindrical body
102a – First end
102b – Second end
102c – Flat circumferential portion
104 – First bore
106 – Second bore
108 – Axle
110 – Wheel hub
112 – Rim portion
114 – Plurality of holes
116 – Fastener
118 – Brake liner
120 – Brake pad
122 – Inner surface
124 – Intermittent connecting portion
126 – Draft angle
128 – face
130 – Outer surface of the flat circumferential portion
132 – Axle Spindle
,CLAIMS:WE CLAIM
1. A brake drum (100) for a vehicle, the brake drum (100) comprising:
a hollow cylindrical body (102) having a first end (102a) and a second end (102b); and
a flat circumferential portion (102c) provided between the first end (102a) and the second end (102b), the flat circumferential portion (102c) aligned parallelly to a central axis (A-A’) of the hollow cylindrical body (102),
wherein the flat circumferential portion (102c) being adapted to maintain perpendicularity with a rim portion (112) of the hollow cylindrical body (102).

2. The brake drum (100) as claimed in claim 1, wherein the flat circumferential portion (102c) comprises an inner surface (122), the inner surface (122) being adapted to engage with a brake pad (120) of a brake assembly of the vehicle,
wherein the inner surface (122) adapted to maintain perpendicularity with a face (128) of the rim portion (112).

3. The brake drum (100) as claimed in claim 1, wherein the flat circumferential portion (102c) comprises an outer surface (130) and an inner surface (122), the outer surface (130) being adapted to taper outwardly from the inner surface (122) at a draft angle (126).

4. The brake drum (100) as claimed in claim 3, wherein the draft angle between the outer surface (130) and the inner surface (122) is 2.5 degrees to 3 degrees.

5. The brake drum (100) as claimed in claim 1, wherein the perpendicularly maintained between the hollow cylindrical body (102) and the rim portion (112) is within 0.05mm.

6. The brake drum (100) as claimed in claim 1, wherein the hollow cylindrical body (102) is casted.

Dated this 8th day of February 2024.
RAMKRISHNA FORGINGS LIMITED
By their Agent & Attorney

(Adheesh Nargolkar)
of Khaitan & Co
Reg No IN/PA-1086