Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

A BRAKE ASSEMBLY AND A BRAKE ROTOR THEREOF

APPLICANT:

TVS MOTOR COMPANY LIMITED, an Indian Company at: “Chaitanya”, No.12 Khader Nawaz Khan Road, Nungambakkam, Chennai 600 006.

The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD
[0001] The present subject matter relates generally to a brake assembly and a brake rotor. More particularly but not exclusively, the present subject matter relates to a brake assembly and a brake rotor of a vehicle.

BACKGROUND
[0002] Conventionally, various types of metals have been used for manufacturing brake rotor in vehicles by many manufacturers in the industry. Initially, for example, copper was used. But the braking effect of copper material was not that good because of durability issues. The industry moved towards the use of cast iron. Cast iron has good frictional properties, low cost, relatively easy to manufacture as compared to other materials available, and also exhibits good thermal stability. The drawback of using cast iron is that it is heavy thereby adding a lot of weight to the vehicle. Therefore, cast iron adversely affected the center of gravity, balancing, and consequent handling of the vehicle. The added weight due to use of the cast iron also affects fuel efficiency of the vehicle as more fuel is used for running of the vehicle.
[0003] One way of reducing the weight and still be able to use the cast iron is to reduce the thickness of the brake rotor, but this reduces the durability as well as life of the brake rotor, thus forcing a user of the vehicle to frequently change the brake rotor.
[0004] The existing materials used in the brake rotor exhibits delay in braking response due to lower coefficient of friction between the brake rotor and a brake pad.
[0005] Apart from this, higher peak temperature occurs at a braking surface of the brake rotor leading to abnormalities like thermal erosion, uneven wear, thermal distortion of the brake rotor and system seize (glazing). In addition to this, brake noises are generated due to the brake rotor wear, which is undesirable, leading to customer dissatisfaction. The erosion life of the brake rotor using known materials exhibits lower corrosion life (i.e. the material gets corroded very soon and early wear of the brake rotor happens) with respect to resistance to different environmental conditions.
[0006] In another known art, stainless steel is used for manufacturing the brake rotor. Existing design of steel brake rotor has a limitation in that it increases the hardness operating band due to risk of reduction in impact toughness which is crucial for braking function. Also, material of brake rotor having a substantial is not desirable at all because increases the weight of the vehicle.
[0007] Therefore, it is important to overcome the drawbacks in the prior art mentioned above and provide an improved brake system which is light weight, exhibits good thermal stability, highly durable, resistant to corrosion and possesses better frictional properties.

BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The details are described with reference to an embodiment of a brake assembly and a brake rotor along with the accompanying figures. The same numbers are used throughout the drawings to reference similar features and components.
[0009] Figure 1 illustrates a side perspective view of a brake assembly in one embodiment of the invention.
[0010] Figure 2 illustrates a side view of a brake rotor in one embodiment of the invention.
[0011] Figure 3 illustrates a sectional view of a brake rotor in one embodiment of the invention.

SUMMARY OF THE INVENTION
[0012] The present subject matter relates generally to a brake assembly and a brake rotor. The brake rotor is provided with a double layer coating. The first layer is disposed on the plurality of brake engagement surfaces of the brake rotor. The second layer is disposed on the first layer. The second layer is more porous than the first layer.
DETAILED DESCRIPTION
[0013] In order to achieve one or more of the above-mentioned objectives and overcome the related problems, the present invention provides a brake rotor and a brake assembly comprising said rotor among other novel and inventive features.
[0014] As per one embodiment of the invention, the brake rotor is configured to rotate in conjunction with a rotation of a rotating member around an axis (X-X’). The rotating member includes but not limited to a wheel of a vehicle. The brake rotor comprises at least one axial side, a plurality of brake engagement surfaces, a first layer, and a second layer. The first and second layers can be of same or different materials. The plurality of brake engagement surfaces are provided on a portion of the at least one axial side of the brake rotor. The plurality of brake engagement surfaces are configured for frictional engagement with at least one pair of brake pads upon an actuation of the brake-assembly. The first layer is disposed on the plurality of brake engagement surfaces. The second layer is disposed on the first layer. The second layer is more porous than the first layer.
[0015] The first layer and the second layer are configured to decrease the wear and increase the life of the brake rotor. The multi-layered coating is done only at the plurality of brake engagement surfaces and not at entire axial side of the brake rotor in order to prevent any unnecessary increase in the weight of the brake rotor. The second layer, which is in contact with the brake pad has higher porosity. Therefore, the porous second layer facilitates in cooling of the brake rotor by quick dissipation of heat in function and preventing any deformational damage from frictional heat during operation of the brake assembly. High porosity of the second layer also contributes to enhancement of the frictional property of the plurality of brake engagement surfaces thereby improving the brake response and reduction in noise during brake engagement.
[0016] On the other hand, the first layer has low porosity in comparison to second layer. Due to this, the first layer has high thermal conductivity. The first layer improves the hardness, durability, and offers better wear resistance. This layer acts as a thermal barrier and not as a conductor. Thus, first layer contributes to preventing the transfer of heat from second layer to the substrate layer and protecting the substrate layer from any deformational damage from frictional heat or mechanical wear and tear.
[0017] As per one embodiment of the invention, the plurality of brake engagement surfaces are provided on a periphery of the at least one axial side of the brake rotor. The multi-layered coating is done only on the peripheral surfaces, at the entire circumference and not at entire axial side of brake rotor in order to prevent any unnecessary increase in weight of the rotor.
[0018] As per one embodiment of the invention, the brake rotor is in a shape of a disc.
[0019] As per one embodiment of the invention, the brake rotor is made of a substrate material. The substrate material is selected from a group consisting of metals including aluminum, magnesium, non-metallic substances, metal alloys including non-metallic substances, metal alloys excluding non-metallic substances, or a combination thereof.
[0020] As per one embodiment of the invention, the brake rotor is made of a substrate material. The first layer and the second layer are made of chemical compounds which are made using the very substrate material of the brake rotor.
[0021] As per one embodiment of the invention, the substrate includes a metal. The first layer and the second layer are made using an oxide of the metal of the substrate of the rotor. The oxide composition of the first layer and the second layer prevents the substrate metal from corrosion and and higher wear resistance is achieved. The oxide composition ensures that coating is uniform and prevents coating peel-off after few cycles of operation.
[0022] As per one embodiment of the invention, the brake rotor is made of aluminium. The first layer is an oxide of aluminium and the second layer is also an oxide of aluminium. Aluminium exhibits good thermal conductivity and is light in weight. Use of aluminium does not add substantial weight to the vehicle and also does not affect the center of gravity, balancing, and handling of the vehicle. This also helps in reduction of fuel consumption and enhancing mileage. Currently, stainless steel used to manufacture the brake rotor has density of 7.8g/cc. But with the proposed invention, the density of oxidized brake rotor is 2.7 g/cc. So, around 60% of weight saving has been achieved through this design.
[0023] As per one embodiment of the invention, the brake rotor is made of wrought aluminium.
[0024] As per one embodiment of the invention, a thickness of the first layer is in the range of 15 Micron-30 Micron.
[0025] As per one embodiment of the invention, the first layer is a non-porous layer.
[0026] As per one embodiment of the invention, a thickness of the second layer is in the range of 30 microns-50 microns. The second layer is subjected to a higher mechanical wear and tear in comparison to first layer because it is in direct contact with the at least one pair of brake pads. Therefore, the thickness of the second layer is greater than first layer in order to compensate the higher mechanical wear experienced by second layer. Thus, frequent replacement of brake rotor is not required as durability of brake rotor is significantly improved due to greater thickness of the second layer.
[0027] As per one embodiment of the invention, the second layer is a porous layer and a porosity of second layer is in the range of 40-70%.
[0028] As per another embodiment of the invention, a brake assembly is disclosed which comprises at least one brake rotor, at least one pair of brake pads, a plurality of brake engagement surfaces, a first layer and a second layer. The at least one brake rotor is configured to rotate in conjunction with a rotation of the rotating member around an axis (X-X’) of rotation. The rotating member includes but not limited to a wheel of a vehicle. The at least one pair of brake pads are disposed on at least one axial side of the at least one brake rotor around at least a portion of a periphery of the at least one axial side of the of the brake rotor. The plurality of brake engagement surfaces are provided on a portion of the at least one axial side of the at least one brake rotor. The plurality of brake engagement surfaces are configured for frictional engagement with at least one pair of brake pads upon an actuation of the brake-assembly. The first layer is disposed on the plurality of brake engagement surfaces. The second layer is disposed on the first layer. A porosity of the second layer is more than a porosity of the first layer.
[0029] As per another embodiment of the invention, the plurality of brake engagement surfaces of the brake assembly are provided on a periphery of the at least one axial side of the brake rotor.
[0030] As per another embodiment of the invention, the brake rotor of the brake assembly is made of a substrate material. The substrate material is selected from a group consisting of metals including aluminum, magnesium, non-metallic substances, metal alloys including non-metallic substances, metal alloys excluding non-metallic substances, or a combination thereof.
[0031] As per another embodiment of the invention, the brake rotor is made of a substrate material. The first layer and the second layer are made of a chemical compound made using the substrate material.
[0032] As per another embodiment of the invention, the brake rotor is made of aluminium. The first layer and the second layer are made of aluminium oxide.
[0033] As per another embodiment of the invention, a thickness of the first layer is in the range of 15 Microns-30 Microns.
[0034] As per another embodiment of the invention, the first layer is a non-porous layer.
[0035] As per another embodiment of the invention, a thickness of the second layer is in the range of 30 Microns-50 Microns.
[0036] As per another embodiment of the invention, a porosity of the second layer is in the range of 40-70%.
[0037] As per yet another embodiment, the invention includes a vehicle which comprises at least one rotating member and a brake assembly. The at least one rotatable member is configured to rotatably support a movement of the vehicle. The rotating member includes but not limited to a wheel of a vehicle. The rotating member can also include drive chain, gears or other rotating parts of a machine or apparatus that is optionally or necessarily required to be decelerated or stopped. For example, in case of wind turbines, generators, hydro-generators, etc. emergency brakes are required to be applied. A skilled person can apply the teachings of the present invention to various fields apart from automobiles and the present inventio is not limited to the embodiments shown herein. The brake assembly is configured to decelerate a rotation of the at least one such rotating member. The brake assembly comprises at least one brake rotor, at least one pair of brake pads, a plurality of brake engagement surfaces, a first layer and a second layer. The at least one brake rotor is configured to rotate in conjunction with a rotation of the rotating member around an axis (X-X’) of rotation. The at least one pair of brake pads are disposed on the at least one axial side of the at least one brake rotor around at least a portion of a periphery of the at least one axial side of the of the brake rotor. The plurality of brake engagement surfaces are provided on a portion of the at least one axial side of the at least one brake rotor. The plurality of brake engagement surfaces are configured for frictional engagement with at least one pair of brake pads upon an actuation of the brake-assembly. The first layer is disposed on the plurality of brake engagement surfaces. The second layer is disposed on the first layer. A porosity of the second layer is more than a porosity of the first layer.
[0038] The embodiments of the present invention will now be described in detail with reference to an embodiment in brake rotor and brake assembly along with the accompanying drawings. However, the disclosed invention is not limited to the present embodiments.
[0039] The embodiments shown in Figure 1 illustrates a side perspective view of a brake assembly (200) for a rotating member (not shown). The brake assembly (200) is configured to decelerate a rotation of the rotating member (not shown). The brake assembly (200) comprises at least one brake rotor (201) and at least one pair of brake pads (202a, 202b). The at least one brake rotor (201) is configured to rotate in conjunction with a rotation of the rotating member around an axis (not shown) of rotation. The at least one pair of brake pads (202a, 202b) is disposed on the at least one axial side (201a, 201b) of the at least one brake rotor (201) around at least a portion of a periphery of the at least one axial side (201a, 201b) of the of the brake rotor (201). The plurality of brake engagement surfaces (S1, S2) are provided on a portion of the at least one axial side (201a, 201b) of the at least one brake rotor (201). The plurality of brake engagement surfaces (S1, S2) is configured for frictional engagement with the at least one pair of brake pads (202a, 202b) upon an actuation of the brake-assembly (200). The plurality of brake engagement surfaces (S1, S2) are provided on a periphery of the at least one axial side (201a, 201b) of the brake rotor (201). As shown in this embodiment of the invention, the brake rotor (201) is in a shape of a disc which typically referred as a brake disc.
[0040] The embodiments shown in Figure 2 and Figure 3 are taken together for discussion. The embodiment shown in Figure 3 illustrates a side view of a brake rotor (201) for a brake assembly (shown in Figure 1). The embodiments shown in Figure 3 illustrates a sectional view of a brake rotor (201). The brake rotor (201) is configured to rotate in conjunction with a rotation of a rotating member (not shown) around an axis (X-X’). The brake rotor (201) is provided with a double layer coating at the plurality of brake engagement surfaces (S1, S2). As can be seen in this embodiment, the brake rotor (201) is in a shape of the disc. The brake rotor (201) is made of a substrate material. A first layer (L1) is disposed on the plurality of brake engagement surfaces (S1, S2) of the brake rotor (201). A second layer (L2) is disposed on the first layer (L1). The second layer (L2) is more porous than the first layer (L1). The substrate with which the brake rotor (201) can be made includes a metal. The first layer (L1) and second layer (L2) are made using an oxide of the metal of the substrate. As per one of the embodiments, the substrate is made of aluminium, while the first layer (L1) and the second layer (L2) is made of aluminium oxide. A thickness of the first layer (L1) is in the range of 15 Micron-30 Micron while a thickness of the second layer (L2) is in the range of 30 Micron-50 Micron. The first layer (L1) is a non-porous layer. The second layer (L2) is a porous layer and a porosity of second layer (L2) is in the range of 40-70%. The plurality of brake engagement surfaces (S1, S2) of the brake rotor (201) are oxidized in a controlled atmosphere by following the process of PEO (Plasma Electrolytic Oxidation) or MAO (Micro Arc Oxidation) for creating the first layer (L1) and second layer (L2) of different thickness and porosity. In another embodiment, the plurality of brake engagement surfaces (S1, S2) of the brake rotor (201) can be oxidized in a controlled atmosphere by any other similar methods already known in the art.
[0041] The proposed invention enhances the performances of the vehicle by improving the brake response. Improved braking facilitates the reduction of fuel consumption, enhancing mileage. The durability and life of the brake rotor (201) is increased due to the coating of multi layered oxide. Improved thermal conductivity by the use of aluminum material with multiple layers facilitates in cooling of the brake rotor (201). Reduced brake noise ensures comfort for the user of the vehicle. The multi layered oxidized coating is done only at the plurality of brake engagement surfaces (S1, S2) of the brake rotor (201) to avoid any unnecessary increase of weight.
[0042] The embodiments of this invention are not limited to particularly vehicle and can cover any type of application involving the rotating member. For example, as used in this specification and the appended claims, the singular forms “a,” “an” and ““they”” can include plural referents unless the content clearly indicates otherwise. Further, when introducing elements/components/etc. of the assembly/system described and/or illustrated herein, the articles “a”, “an”, “the”, and “said” are intended to mean that there is one or more of the element(s)/component(s)/etc. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional element(s)/component(s)/etc. other than the listed element(s)/component(s)/etc.
[0043] This written description uses examples to provide details on the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
[0044] It is to be understood that the aspects of the embodiments are not necessarily limited to the features described herein. Many modifications and variations of the present subject matter are possible in the light of above disclosure.

LIST OF REFERENCE NUMERALS

200 Brake Assembly
201
201a, 201b Brake rotor
At least one Axial side of brake rotor
202a, 202b
S1, S2
L1
L2 At least one pair of Brake Pads
Plurality of Brake Engagement Surfaces
First Layer
Second Layer
X-X’ Axis of rotation of the brake rotor

, Claims:We Claim:
1. A brake rotor (201) for a brake assembly (200), the brake rotor (201) being configured to rotate in conjunction with a rotation of a rotating member around an axis (X-X’), the brake rotor (201) comprising:
at least one axial side (201a, 201b);
a plurality of brake engagement surfaces (S1, S2), the plurality of brake engagement surfaces (S1, S2) being provided on a portion of the at least one axial side (201a, 201b) of the brake rotor (201) and the plurality of brake engagement surfaces (S1, S2) being configured for frictional engagement with at least one pair of brake pads (202a, 202b) upon an actuation of the brake-assembly (200);
a first layer (L1), the first layer (L1) being disposed on the plurality of brake engagement surfaces (S1, S2);
a second layer (L2), the second layer (L2) being disposed on the first layer (L1); and
the second layer (L2) being more porous than the first layer (L1).
2. The brake rotor (201) for the brake assembly (200) as claimed in claim 1, wherein the plurality of brake engagement surfaces (S1, S2) being provided on a periphery of the at least one axial side (201a, 201b) of the brake rotor (201).
3. The brake rotor (201) for the brake assembly (200) as claimed in claim 1, wherein the brake rotor (201) being in a shape of a disc.
4. The brake rotor (201) for the brake assembly (200) as claimed in claim 1, wherein the brake rotor (201) being made of a substrate material, the substrate material being selected from a group consisting of metals including aluminium, magnesium, non-metallic substances, metal alloys including non-metallic substances, metal alloys excluding non-metallic substances, or a combination thereof.
5. The brake rotor (201) for the brake assembly (200) as claimed in claim 1, wherein the brake rotor (201) being made of a substrate material, and the first layer (L1) and the second layer (L2) being a made of a chemical compound made from the substrate material.
6. The brake rotor (201) for the brake assembly (200) as claimed in claim 4 wherein the substrate includes a metal, the first layer (L1) and the second layer L2 being made using an oxide of the metal.
7. The brake rotor (201) for the brake assembly (200) as claimed in claim 1 wherein the brake rotor (201) being made of aluminium, the first layer (L1) and the second layer (L2) being made of aluminium oxide.
8. The brake rotor (201) for the brake assembly (200) as claimed in claim 1, wherein a thickness of the first layer (L1) being in the range of 15 Micron-30 Micron.
9. The brake rotor (201) for the brake assembly (200) as claimed in claim 1, wherein the first layer (L1) being a non-porous layer.
10. The brake rotor (201) for the brake assembly (200) as claimed in claim 1, wherein a thickness of the second layer (L2) being in the range of 30 Micron-50 Micron.
11. The brake rotor (201) for the brake assembly (200) as claimed in claim 1, wherein a porosity of second layer (L2) being in the range of 40-70%.
12. A brake assembly (200) for a rotating member, the brake assembly (200) comprising:
at least one brake rotor (201), the at least one brake rotor (201) being configured to rotate in conjunction with a rotation of the rotating member around an axis (X-X’) of rotation;
at least one pair of brake pads (202a, 202b), the at least one pair of brake pads (202a, 202b) being disposed on at least one axial side (201a, 201b) of the at least one brake rotor (201) around at least a portion of a periphery of the at least one axial side (201a, 201b) of the of the brake rotor (201);
a plurality of brake engagement surfaces (S1, S2), the plurality of brake engagement surfaces (S1, S2) being provided on a portion of the at least one axial side (201a, 201b) of the at least one brake rotor (201) and the plurality of brake engagement surfaces (S1, S2) being configured for frictional engagement with the at least one pair of brake pads (202a, 202b) upon an actuation of the brake-assembly (200); and
a first layer (L1), the first layer (L1) being disposed on the plurality of brake engagement surfaces (S1, S2);
a second layer (L2), the second layer (L2) being disposed on the first layer (L1);
and the second layer (L2) being more porous than the first layer (L1).
13. The brake assembly (200) for the rotating member as claimed in claim 12, wherein the plurality of brake engagement surfaces (S1, S2) being provided on a periphery of the at least one axial side (201a, 201b) of the brake rotor (201).
14. The brake assembly (200) for the rotating member as claimed in claim 12, the brake rotor (201) being made of a substrate material, the substrate material being selected from a group consisting of aluminium, magnesium, , metal alloys including non-metallic substances or a combination thereof.
15. The brake assembly (200) for the rotating member as claimed in claim 12, wherein the brake rotor (201) being made of a substrate material, and the first layer (L1) and the second layer (L2) being made of a chemical compound made using the substrate material.
16. The brake assembly (200) for the rotating member as claimed in claim 12, wherein the brake rotor (201) being made of aluminium and the first layer (L1) and the second layer (L2) being made of aluminium oxide.
17. The brake assembly (200) for the rotating member as claimed in claim 12, wherein a thickness of the first layer (L1) being in the range of 15 Microns-30 Microns.
18. The brake assembly (200) for the rotating member as claimed in claim 12, wherein the first layer (L1) being a non-porous layer.
19. The brake assembly (200) for the rotating member as claimed in claim 12, wherein a thickness of the second layer (L2) being in the range of 30 Micron-50 Micron.
20. The brake assembly (200) for the rotating member as claimed in claim 14, wherein a porosity of the second layer (L2) being in the range of 40-70%.
21. A vehicle, the vehicle comprising:
at least one rotating member, the at least one rotatable member being configured to rotatably support a movement of the vehicle; and
a brake assembly (200), the brake assembly (200) being configured to decelerate a rotation of the at least one rotating member, the brake assembly (200) comprising
at least one brake rotor (201), the at least one brake rotor (201) being configured to rotate in conjunction with a rotation of the rotating member around an axis (X-X’) of rotation,
at least one pair of brake pads (202a, 202b), the at least one pair of brake pads (202a, 202b) being disposed on at least one axial side (201a,201b) of the at least one brake rotor (201) around at least a portion of a periphery of the brake rotor (201),
a plurality of brake engagement surfaces (S1, S2), the plurality of brake engagement surfaces (S1, S2) being provided on a portion of the at least one axial side (201a, 201b) of the at least one brake rotor (201) and the plurality of brake engagement surfaces (S1, S2) being configured for frictional engagement with the at least one pair of brake pads (202a, 202b) upon an actuation of the brake-assembly (200),
a first layer (L1), the first layer (L1) being disposed on the plurality of brake engagement surfaces (S1, S2),
a second layer (L2), the second layer (L2) being disposed on the first layer (L1), and the second layer (L2) being more porous than the first layer (L1).
Dated this 8th day of June, 2023
(Digitally Signed)
Sudarshan Singh Shekhawat
IN/PA-1611
Agent for the Applicant