Description:FORM 2

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

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

A BRAKE ASSMBLY FOR A VEHICLE AND AN ELASTIC MEMBER 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. More particularly but not exclusively, the present subject matter relates to a brake assembly of a vehicle with an elastic member.

BACKGROUND
[0002] Brake systems are crucial in any vehicular configuration. Brake systems are also hitherto known to be employed in no vehicular configurations with equal importance. In vehicles, there are two types of braking systems that are commonly known viz. the drum brake system and the disc brake system. Many vehicles use drum brake systems because of their longer life and cost-effectiveness. Drum brakes are used in most two-wheelers, cars, heavy-duty trucks, buses and other vehicular applications. The components of a drum brake system typically include backing plate, a rotating member, such as a brake drum, an arcuate member such as a brake shoe with liner material, cam member, an elastic member such as return springs and an anchor pin. The backing plate acts as a base for all the other components. It supports the housing and adds to the rigidity of the whole system. The brake drum is usually attached to a wheel and it rotates along with the wheel and the axle. The shoes are usually arcuate shaped and situated inside the brake drum and a liner material is provided on a surface of the shoes. The shoes are connected on one side by an anchor pin (which also acts as a pivot point) and separated by a cam on the other side. The return springs typically made of elastic material are connected to both the shoes. When the brake pedal is applied, the cam rotates which forces the shoes to pivot about the anchor pin. This in turn causes the liner (friction material) to come in contact with at least one surface of the brake drum. For example, if the brake shoe is installed inside the drum, the brake shoe liner will come in contact with the inner surface. Alternatively, it is also possible to construct a brake assembly where the brake shoe is installed near an outer surface of the rotating member like a brake drum and upon actuation of brakes, the brake liner comes in contact with an outer surface of the brake drum. Since the brake drum rotates with the wheel and the shoe is stationery, the resulting friction will provide the required deceleration in the drum and thereby the wheel and the vehicle. During this, there is an equilibrium between the applied force and the force of return springs acting in opposite directions. However, once the force on the pedal is released, the return springs forces the shoes to return to their original position. In the drum brake, the fluctuations in input force are transmitted through the retractor springs to the brake shoes causing them to produce a squeal noise. Further, during the cold and rainy weather noise frequency is very high as compared to summer. The noise produced by the brakes causes discomfort to the rider and surroundings.

BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The invention therefore pertains to providing a brake assembly of the vehicle to prevent/reduce the fluctuations caused by the conventional drum brake assembly in the vehicles.
[0004] The details are described with reference to an embodiment of a brake assembly along with the accompanying figures. The same numbers are used throughout the drawings to reference similar features and components.
[0005] Figure 1a, 1b and 1c illustrate the front, top and side views respectively of the conventional drum brake assembly in one embodiment of the invention.
[0006] Figures 2 illustrate an exploded view of the conventional drum brake assembly.
[0007] Figure 3a, 3b and 3c, illustrate the side perspective, front and exploded views, respectively of the modified drum brake assembly in one embodiment of the invention.
[0008] Figure 4a, 4b and 4c illustrate the top, front and side views, respectively of the elastic member with the dampening material of the brake assembly in one embodiment of the invention.
[0009] Figure 5a, 5b and 5c illustrate the top cut-sectional, front cut-sectional view and side cut-sectional views, respectively of the elastic member with a dampening material of the brake assembly in another embodiment of the invention.

DETAILED DESCRIPTION
[00010] In order to address the problems of the squealing noise during braking, there have been some attempts in the art. A higher grade of brake shoes or brake drum material have been used with better noise suppression but in such a case, a drop is observed in the braking performance and durability. Further, the higher-grade material can reduce the noise in specific scenario only like it can target a dry noise or wet noise. Moreover, the higher-grade materials also significantly increase the cost of the assembly. Therefore, higher grade alone may not serve an effective solution. Additionally, the brake shoes are having a limited life. Furthermore, the user tends to apply non uniform actuation force on the brake lever. The actuation force (jerk) in turn will be transferred to the brake shoes. When the brake shoe meets the drum, the unsmooth force further vibrates the brake shoe. Once this vibration reaches a particular frequency, the resonance creates further noise. In addition to that, pulsation is further amplified due to the mechanical linkages to connect the drum brake to a brake lever.
[00011] The above conventional technologies were based on the reactive approach i.e., if noise is generated how to suppress the same by damping the noise and excitation during the contact. Further, any misalignment in the brake system due to geometric variation or wear and tear can also cause or amplify the noise. Furthermore, the structural stiffness of the housing (where a brake shoe is mounted) can be improved. However, again the manufacturing variation leads to noise variation beyond tunned range.
[00012] Therefore, there is a need for an improved brake assembly so that this transmission of fluctuation is prevented so that brake application can feel smoother to the rider. There is a need for a forwarded proactive approach that suppresses the noise at the root level itself and preventing or substantially reducing the excitation.
[00013] Accordingly, the present invention provides a novel brake assembly including an improved elastic member.
[00014] In one embodiment of the invention, a brake assembly is disclosed. The brake assembly comprises a rotating member being configured to be decelerated by said brake assembly upon application of a braking force. In one embodiment, said rotating member can be a brake drum. The assembly further includes at least one arcuate member being retractably installed with said rotating member. The arcuate member has an arcuate surface being configured to contact with a rotating surface of the rotating member when a braking force is applied on the arcuate member, thereby decelerating the rotating member. The brake assembly also comprises of at least one elastic member which is attached to the arcuate member. Further, a dampening material is being provided which is configured to cover at least a portion of the elastic member. The fluctuations in the input brake force which are easily transmitted through the elastic members to the arcuate members, are responsible for causing excitation of the arcuate members which lead to the vibration and squealing noise produced in the brake assembly which often irritates the user and also reduces the life of the brake assembly. The noise also causes disturbances in surroundings. The dampening material on the elastic member, wherein dampening material having predetermined geometrical parameters dampens this brake force fluctuations in the elastic member thereby significantly preventing noise and vibration that occurs while applying the braking force to the brake assembly.
[00015] In another embodiment of the invention, in the brake assembly, the arcuate member is a brake shoe and the arcuate surface of the arcuate member including a frictional liner which is being disposed on the arcuate surface.
[00016] In another embodiment of the invention, the elastic member is being configured to provide a retracting force to the arcuate member when the braking force ceases to act on the arcuate member.
[00017] In another embodiment of the invention, in the brake assembly, the dampening material is including an elastomeric material.
[00018] In another embodiment of the invention, in the brake assembly, the dampening material is applied as a coated layer to the portion of the elastic member. The coated layer of the dampening material is given a predetermined thickness and the coated layer can be accordingly thickened in order to meet the manufacturing requirement.
[00019] The dampening material in the present invention provides dampening characteristics to the elastic members by embedding into the retracting elastic member such that it becomes a single part. This modified elastic member has stiffness, dampening as well as the requisite elastic properties. This is achieved by providing fixed pre-load to the material, which pulls back the arcuate members shoes when brakes are disengaged by the user of the vehicle. The proposed solution decouples the retractor elastic members and the arcuate members from the otherwise mechanically coupled systems. This decoupling results in prevention of noise during the contact between the frictional liners (on arcuate surface of the arcuate members) and the rotating surface of the rotating member. In one aspect of the invention, the rotating surface can be an outer surface of the rotating member. This dampening material dampens the fluctuations in the applied input brake force, due to its viscoelastic nature. Since the vibration and the squeal noise of the arcuate members is dependent on the brake force, the dampening thereby prevents the fluctuations. The dampening material contributes to handling the twin responsibilities of returning the arcuate members to their original position and to dampen the input force fluctuations.
[00020] In another embodiment of the invention, in the brake assembly, the elastic member is a spring.
[00021] In another embodiment of the invention, in the brake assembly, the dampening material is configured to cover an inner surface of the elastic member. In this embodiment, the inner surface of the elastic member is filled with the dampening material. In another embodiments, a hollow structure made of the dampening material can also be placed on the outer circumferential surface of the elastic member.
[00022] In another embodiment of the invention, in the brake assembly, the elastic member has an inner hollow portion. The inner hollow portion of the elastic member is filled by the dampening material up to a predetermined level along the length of the elastic member.
[00023] In another embodiment of the invention, in the brake assembly, the predetermined level ranges from Lc to Lc/2, wherein the L is the total length of the elastic member that is to be dampened.
[00024] In another embodiment of the invention, in the brake assembly, the rotating member is a brake drum installed on a wheel of a vehicle.
[00025] In another embodiment of the invention, in the brake assembly, the brake assembly includes two arcuate members which are retractably installed inside the brake drum. Both of the arcuate members are connected by two elastic members at two predefined locations.
[00026] In another embodiment of the invention, in the brake assembly, the dampening material covers the portion of the two elastic members.
[00027] In another embodiment of the invention, in the brake assembly, the elastomeric material is selected from a group consisting of natural rubbers, styrene-butadiene block copolymers, polyisoprene, polybutadiene, ethylene propylene rubber, ethylene propylene diene rubber, silicone elastomers, fluoro-elastomers, polyurethane elastomers, and nitrile rubbers.
[00028] In another embodiment of the invention, in the brake assembly, the elastic member is being substantially made of a solid coil. The elastic member has a median diameter Ds and the coil has a diameter Dw. The dampening material conforms to the profile and configuration of the elastic member wherein said dampening member has an inner diameter Di and an outer diameter Do. In this case, the inner diameter Di ranges from 0 to (Ds – 4Dw) and the outer diameter Do ranges from (Ds + 0.5Dw) to (Ds+ 4Dw).
[00029] In yet another embodiment of the invention, a brake assembly for a vehicle is disclosed. The brake assembly comprises at least one backplate; at least one anchor member being attached to the backplate; at least one cam member being rotatably mounted on the backplate. The cam member being connected to at least one brake actuator. The cam member is being configured to be rotated by a braking force transmitted from the brake actuator. The brake assembly also comprises at least one arcuate member being configured to be retractably mounted on the backplate. The arcuate member is also configured to be pushed by the cam member upon application of the braking force. The brake assembly comprises of at least one frictional liner which is disposed on the arcuate surface of the arcuate member. An at least one elastic member is being attached to the arcuate member. The elastic member is configured to provide retracting force upon application of the braking force. The dampening material is configured to cover at least a portion of the elastic member.
[00030] In yet another embodiment of the invention, an elastic member for a brake assembly is disclosed. The elastic member comprises of a body portion which is configured to provide retractable force upon compression and decompression. The elastic member has an at least one end portion which is configured to be anchored to a part of the brake assembly. A dampening material is being configured to cover at least a part of said body portion of the elastic member.
[00031] In yet another embodiment of the invention, a vehicle is disclosed. The vehicle comprises at least one or more rotary parts which are configured to move the vehicle. The vehicle includes the brake assembly as disclosed herein above.
[00032] The embodiments of the present invention will now be described in detail with reference to an embodiment in a brake assembly along with the accompanying drawings. However, the disclosed invention is not limited to the present embodiments.
[00033] Figure 1a, 1b, 1c, and Figure 2 have been taken together for discussion. The embodiment shown in Figure 1a illustrates a front view of a conventional drum brake assembly 100 for a vehicle (not shown). In this embodiment, the brake assembly 100 comprises of at least a backplate (not shown), at least one anchor member (not shown) being attached to the backplate. A cam member (not shown) being rotatably mounted on the backplate is connected to a brake actuator (not shown). Upon application of the brake by a user of the vehicle, the cam member (not shown) is rotated to transmit the applied force. The conventional drum brake assembly also includes a rotating member such as a brake drum (not shown) which is mounted on a rotary part of the vehicle, such as a wheel. The brake assembly 100 has a pair of arcuate members 101 which are retractably installed with the brake drum of the brake assembly 100. The arcuate members 101 such as a brake shoe have an arcuate surface 101ot (shown in Figure 2) which is configured to contact a rotating surface of the brake drum when a braking force is applied on the arcuate members 101 to decelerate the rotary part of the vehicle. The brake assembly 100 further comprises a pair of elastic members 102a, 102b which are attached to the arcuate members 101. The pair of elastic members 102a, 102b are configured to provide retracting force to the arcuate members 101 when the braking force is applied on the arcuate members 101. In this embodiment, the elastic members 102 are conventional springs simply anchored to the brake assembly 100. In this embodiment, the arcuate surface 101ot of the arcuate member 101 is an outer surface which includes a frictional liner 104 (also shown in Figure 2) being disposed on the arcuate surface 101ot. The frictional liner 104 is responsible for getting in contact with the rotating member of the vehicle when braking force is applied. The contact of these frictional liners 104 with the rotating member of the brake assembly causes friction thereby helping in deceleration of the rotary parts such as the wheels of the vehicle. Figure 1c showing the side view of the brake assembly 101 in one embodiment depicting the two arcuate members 101 facing opposite to each other in their orientation. The discontinuous arcuate portion 101 is made of two substantially semi-circular arcuate portions 101. However, there is no limit to having fixed number of arcuate portions 101 or their orientations. The embodiment shown in Figure 2 shows a side exploded of the conventional drum brake assembly 100 of the vehicle. The frictional liners 104 are shown to have been disposed on the arcuate surface 101ot which in this case is an outer surface of the arcuate members 101. The elastic members 102 are shown that provide retracting force upon application of the braking force.
[00034] Figure 3 illustrates an improved brake assembly 200 in accordance with one embodiment of the present invention. This brake assembly can be installed in a vehicle or for non-vehicular applications requiring a brake assembly. The brake assembly 200 possess similarity to the conventional brake assembly 100 in many features like backplate, anchor member, cam member, arcuate member, frictional liners, elastic members, outer surface of the arcuate member. The basic contents made out in the immediately preceding paragraph are reiterated and not repeated for the sake of brevity. However, the invention discloses the modified brake assembly 200 having a dampening material 103 being used to cover at least a portion of the elastic members 102. In one embodiment of the invention the dampening material 103 is at least partly made using an elastomeric material. In another aspect of the invention the dampening member 103 can be entirely made from an elastomeric material. The dampening material 103 used is said to have a predetermined thickness. The elastomeric material can be one or more of natural rubbers, styrene-butadiene block copolymers, polyisoprene, polybutadiene, ethylene propylene rubber, ethylene propylene diene rubber, silicone elastomers, fluoroelastomers, polyurethane elastomers, and nitrile rubbers.
[00035] Figure 4a, 4b, 4c, 5a, 5b and 5c have been taken together for the discussion. Figure 4a, Figure 4b and Figure 4c illustrate top view, front view and side view of the elastic member 102 of the brake assembly 200 (not shown) along with the dampening member 103. Further, the Figure 5a, Figure 5b and Figure 5c illustrate top cut-sectional view, front cut-sectional view and side cut-sectional view of the elastic member 102 with the dampening member 103 of the brake assembly 200 (not shown). The elastic member 102 comprises of a body portion 102bp and a pair of end portion 102ep. The body portion 102bp is configured to provide retractable force upon compression and decompression caused by the application of the breaking force applied by the user of the vehicle, while the end portions 102ep are attached to at least one arcuate member 101. In another embodiment, the elastic member 102 can be attached to two arcuate members 101 on either end portion 102ep. The dampening material 103 is configured to cover at least a part of the body portion 102bp. In this embodiment, the elastic member 102 is a spring having an inner surface 102ns and an outer surface 102os. The dampening member 103, being made of said elastomeric material, can be configured to be coated as a layer on the inner surface 102s. Similarly, the dampening member 103 can also or alternatively be applied to the outer surface 102s of said elastic member 102. In another embodiment (not shown), the dampening material 103 can be filled inside the cavity of the elastic member 102. The dampening member 103 is configured to cover a predetermined portion of the elastic member 102. If the length of the elastic member is Lc, the dampening member 103 can cover a portion ranging in length from Lc/2 to Lc. Further, in this embodiment, due to cylindric profile of the elastic member 102 i.e., the spring, the dampening material 103 also has a cylindrical profile. The elastic member 102 is being made of a solid coil having a median diameter Ds and said coil having a diameter Dw. Since, the dampening material 103 has a predetermined thickness, the dampening material 103 has an inner diameter Di and an outer diameter Do. In this embodiment, the inner diameter Di ranges from 0 to (Ds – 4Dw) and the outer diameter (Do), ranges from (Ds + 0.5Dw) to (Ds+ 4Dw).
[00036] The embodiments of this invention are not limited to particularly described clutch actuators or systems and/or vehicles as the embodiments can vary and will be understood by skilled artisans to be implementing the single inventive concept. It is further to be understood that all terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting in any manner or scope. 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.
[00037] 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.
[00038] 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:

100 Brake assembly
101 Arcuate member
101a, 101b Two of the arcuate members
101ot arcuate surface
102
102ns
102os Elastic member
Inner surface of elastic member
Outer surface of elastic member
102a, 102b Two of the elastic members
103 Dampening material
102bp Body portion
102ep End portion
104 Frictional liner
Lc Length of the elastic member
Ds Median diameter of coil
Dw Diameter of coil

 
, C , Claims:We Claim:
1. A brake assembly (100) comprising:
a rotating member, said rotating member being configured to be decelerated by said brake assembly (100) upon application of a braking force,
at least one arcuate member (101), said at least one arcuate member (101) being retractably installed with said rotating member and said at least one arcuate member (101) having an arcuate surface (101ot), said arcuate surface (101ot) of said at least one arcuate member (101) being configured to contact a rotating surface of said rotating member upon application of said braking force on said at least one arcuate member (101),
at least one elastic member (102), said at least one elastic member (102) being attached to said at least one arcuate member (101),
a dampening material (103), said dampening material (103) being configured to cover at least a portion of said at least one elastic member (102).
2. The brake assembly (100) as claimed in claim 1, wherein said at least one arcuate member (101) being a brake shoe and wherein said arcuate member (101) including a frictional liner (104) being disposed on said arcuate surface (101ot).
3. The brake assembly (100) as claimed in claim 1, wherein said at least one elastic member (102) being configured to provide a retracting force to said at least one arcuate member (101) when said braking force ceases to act on said at least one arcuate member (101).
4. The brake assembly (100) as claimed in claim 1, wherein said dampening material (103) includes an elastomeric material.
5. The brake assembly (100) as claimed in claim 1, wherein said dampening material (103) being applied as a coated layer to said at least a portion of the elastic member (102), said coated layer having a predetermined thickness.
6. The brake assembly (100) as claimed in claim 1, wherein said at least one elastic member (102) being a spring.
7. The brake assembly (100) as claimed in claim 1, wherein said elastic member (102) includes an inner surface (102ns) and said dampening material (103) covering at least a portion of said inner surface (102ns).
8. The brake assembly (100) as claimed in claim 1, wherein said at least one elastic member (102) has an inner hollow portion, said inner hollow portion being filled by said dampening material (103) upto a predetermined level along a length of said at least one elastic member (102).
9. The brake assembly (100) as claimed in claim 8, wherein said predetermined level ranges from Lc to Lc/2, wherein said Lc is the total length of said at least one elastic member (102).
10. The brake assembly (100) as claimed in claim 1, wherein said rotating member being a brake drum, said brake drum being installed on a vehicle.
11. The brake assembly (100) as claimed in claim 2, wherein said brake assembly (100) includes two of said arcuate members (101a, 101b), said arcuate members (101a, 101b) being connected by two elastic members (102a, 102b) at predefined locations.
12. The brake assembly (100) as claimed in claim 11, wherein said dampening material (103) covering said at least a portion of said two elastic members (102a, 102b).
13. The brake assembly (100) as claimed in claim 3 wherein the elastomeric material is selected from a group consisting of natural rubbers, styrene-butadiene block copolymers, polyisoprene, polybutadiene, ethylene propylene rubber, ethylene propylene diene rubber, silicone elastomers, fluoroelastomers, polyurethane elastomers, and nitrile rubbers.
14. The brake assembly (100) as claimed in claim 1 wherein said at least one elastic member (102) being substantially made of a solid coil, said at least one elastic member (102) having a median diameter Ds and said coil having a diameter Dw; and
said dampening material (103) conforming to the configuration of said elastic member (102), and at least a portion of said dampening material (103) having predetermined parameters.
15. The brake assembly (100) for a vehicle, said predetermined parameters includes a first set of values, said first set of values includes an inner diameter Di and an outer diameter Do; wherein
said inner diameter Di ranges from 0 to (Ds – 4Dw) and
said outer diameter (Do), ranges from (Ds + 0.5Dw) to (Ds+ 4Dw).
16. A brake assembly (100) for a vehicle, said brake assembly (100) comprising:
at least one backplate;
at least one anchor member, said anchor member being attached to said backplate;
at least one cam member, said cam member being rotatably mounted on said backplate and said cam member being connected to at least one brake actuator and said cam member being configured to be rotated by a braking force transmitted from said brake actuator;
at least one arcuate member (101), said at least one arcuate member (101) being configured to be retractably mounted on said backplate and being configured to be pushed by said cam member upon application of said braking force;
at least one frictional liner (104), said frictional liner (104) being disposed on an arcuate surface (101ot) of said at least one arcuate member (101);
at least one elastic member (102), said at least one elastic member (102) being attached to said at least one arcuate member (101) and said at least one elastic member (102) ; and
a dampening material (103), said dampening material (103) being configured to cover said at least a portion of said at least one elastic member (102).
17. An elastic member (102) for a brake assembly (100), said elastic member (102) comprising:
a body portion (102bp), said body portion (102bp) being configured to provide retractable force upon compression and decompression,
at least one end portion (102ep), said end portion (102ep) being configured to be anchored to a part of said brake assembly (100),
a dampening material (103), said dampening material (103) being configured to cover at least a part of said body portion (102bp).
18. A vehicle comprising:
at least one or more rotary parts, said at least one or more rotary parts being configured to move said vehicle;
a brake assembly (100) being installed on said rotary part of the vehicle, said brake assembly (100) including
a rotating member, said rotating member configured to be decelerated by said brake assembly upon application of a braking force, thereby decelerating said vehicle,
at least one arcuate member (101), said at least one arcuate member (101) being retractably installed with said rotating member and said at least one arcuate member (101) having an arcuate surface (101ot), said arcuate surface (101ot) of said at least one arcuate member (101) being configured to contact a rotating surface of said rotating member upon application of said braking force on said at least one arcuate member (101),
at least one elastic member (102), said at least one elastic member (102) being attached to said at least one arcuate member (101),
a dampening material (103), said dampening material (103) being configured to cover at least a portion of said at least one elastic member (102) such that said dampening material (103) controls at least one of a vehicle operating parameter value(s).
19. The vehicle as claimed in claim 18, said vehicle operating parameter value(s) includes braking performance, vehicle range/mileage, reduction in squeal noise.
Dated this the 5th day of January 2023
(Digitally Signed)
Sudarshan Singh Shekhawat
IN/PA-1611
Agent for the Applicant