DESC:TECHNICAL FIELD
[0001] The present subject matter generally relates to the field of braking systems, and more particularly, relates to braking systems that utilize link-ages or brake rods to transmit brake-generated loads from a brake assembly to a wheel of a vehicle.

BACKGROUND
[0002] Generally, two wheeled motor vehicles have either a drum brake system or a disk brake system or both. The drum brake system is essentially comprised in a wheel hub of a two wheeled motor vehicle. The wheel hub has a back plate. The back plate of the wheel hub is mounted on a drive shaft which rotates axially in response to engine output. Further, the wheel hub has one or more brake cylinders along with brake pads mounted on the back plate.
[0003] The wheel hub further has a brake drum, also known as a wheel hub drum. The brake drum encompasses the brake cylinders and the brake pads and is circumferentially mounted on the back plate. The brake drum has a circular contour and has a plurality of mounting holes along its periphery. The mounting holes of the brake drum correspond to mounting holes of a tyre rim. Accordingly, the tyre rim is detachably mounted on the brake drum. When brakes are applied, the brake pads mounted on the back plate frictionally engage with inner wall of the brake drum thereby slowing down and eventually stopping rotation of the wheel.
[0004] Typically, the rear wheel brake assembly in such two-wheeled motor vehicles further consists of a brake rod. One end of the brake rod is connected to a brake pedal attached to a footrest bracket. Here, the brake rod is connected to the brake pedal through a brake hinge. Thus, the brake hinge is used to connect the brake rod with the brake pedal. The other end of the brake rod is connected to a cam lever on the rear wheel. Once, the user applies a force on the brake pedal, the braking mechanism is initiated. The brake hinge transfers that force to the brake rod, which further transfers it to the cam lever to apply the brakes on the rear wheel.

BRIEF DESCRIPTION OF DRAWINGS
[0005] The detailed description is described with reference to the accompanying figures, which is related to a two-wheeled vehicle having a brake assembly being one embodiment of the present subject matter. However, the present subject matter is not limited to the depicted embodiment(s) and is applicable to all kinds of vehicle such as two-wheeled vehicle, three-wheeled vehicle, four-wheeled vehicle with any kind of drum brake assembly and the like. In the figures, the same or similar numbers are used throughout to reference features and components.
[0006] Fig. 1 depicts a typical right-side view of an exemplary vehicle in accordance with an embodiment of the present subject matter.
[0007] Fig. 2(a) illustrates a left side view of a brake rod in accordance with an embodiment of the present subject matter.
[0008] Fig. 2(b) illustrates a bottom view of the brake rod in accordance with an embodiment of the present subject matter.
[0009] Fig. 2(c) illustrates a sectional bottom view of the brake rod in accordance with an embodiment of the present subject matter.
[00010] Fig. 3(a) illustrates a front right top view of the brake rod in accordance with an embodiment of the present subject matter.
[00011] Fig. 3(b) illustrates a rear left top view of the brake rod in accordance with an embodiment of the present subject matter.
[00012] Fig. 4(a) illustrates a rear left top view of a brake hinge in accordance with an embodiment of the present subject matter.
[00013] Fig. 4(b) illustrates a sectional bottom view of the brake hinge in accordance with an embodiment of the present subject matter.
[00014] Fig. 5(a) illustrates a rear left top view of a rear bend portion of the brake rod in accordance with an embodiment of the present subject matter.
[00015] Fig. 5(b) illustrates a sectional bottom view of the rear bend portion of the brake rod in accordance with an embodiment of the present subject matter
DETAILED DESCRIPTION
[00016] Exemplary embodiments detailing features of a brake assembly in a two-wheeled vehicle, in accordance with the present subject matter will be described hereunder with reference to the accompanying drawings. Various aspects of different embodiments of the present invention will become discernible from the following description set out hereunder. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the present subject matter. Further, it is to be noted that terms “upper”, “lower”, “right”, “left”, “front”, “forward”, “rearward”, “downward”, “upward”, “top”, “bottom” and like terms are used herein based on the illustrated state or in a standing state of the two-wheeled vehicle with a driver riding thereon. Furthermore, a vehicle longitudinal axis refers to a front to rear axis relative to the two-wheeled vehicle, while a vehicle lateral axis refers to a side to side, or left to right axis relative to the two-wheeled vehicle. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
[00017] According to a preferred embodiment, a brake assembly in a two-wheeled vehicle is disclosed. However, the scope of the present subject matter is not limited to only two-wheeled vehicles. It is contemplated that the concepts of the present subject matter may be applied to other types of vehicles and other types of drum brake assemblies within the spirit and scope of this subject matter. Thus, it is also to be understood that the scope of the present invention is not limited to only brake assembly in a two-wheeled vehicle. The detailed explanation of the constitution of parts other than the present subject matter which constitutes an essential part has been omitted at suitable places.
[00018] Generally, in vehicles a brake system is used either to slow down or to stop the moving vehicle. In two-wheeled or three-wheeled vehicles, a drum brake system is used as at least one of the braking systems. The drum brake system is installed on either a front wheel or a rear wheel or on all the wheels of the vehicle. Conventionally, a rear wheel is installed with a drum brake system and the users are habituated to actuate the rear wheel brake. This makes the rear brake an essential active safety feature of the vehicle, which is the drum brake system.
[00019] Such drum brake includes a brake drum having inner wall that surrounds the brake shoes. The inner wall is the inner circumferential wall of the brake drum. When the brake is actuated, the liners of the brake shoes come in contact with the inner wall of the brake drum. Frictional forces acting between the brake shoes and the brake drum surface will slow down the rotation of the wheel and eventually bring the wheel to a stop. Typically, the brake shoes are provided with the frictional material that provides balance of friction characteristics and brake noise control.
[00020] Typically, every motorcycle with rear drum brake consists of a backing plate onto which the cam, brake shoes, springs, and the lever are fixed. The springs control the movement of brake shoes that are actuated by rotation of the cam on its own axis, which in turn is connected to the lever. The lever is connected with the foot brake pedal via a brake rod. The braking torque on a motorcycle with rear drum brake is absorbed by the mechanical link that is normally connected to the swing arm or the rigid frame of the motorcycle.
[00021] One end of the brake rod is connected to a brake pedal attached to a footrest bracket. Here, the brake rod is connected to the brake pedal through a brake hinge. Thus, the brake hinge is used to connect the brake rod with the brake pedal. The other end of the brake rod is connected to a cam lever on the rear wheel. Once, the user applies a force on the brake pedal, the braking mechanism is initiated. The brake hinge transfers that force to the brake rod, which further transfers it to the cam lever to apply the brakes on the rear wheel. Herein, the brake rod is a load bearing member as the force applied by the user of the two-wheeled vehicle is transmitted to the brake mechanism attached to the rear wheel.
[00022] The routing of brake rod is a major concern since it has to be routed from various different components such as silencer, swing arm and a muffler panel from the exhaust system of the vehicle. Such layout constraints necessitate the requirement to create bends in the brake rod instead of having a straight brake rod. Such bends are required to prevent rubbing of brake rod against such different components through which it is being routed.
[00023] Furthermore, it is not desirable to have a straight brake rod. Conventionally, brake rods should be parallel to the direction of the actuation having a lateral offset between a first imaginary plane across the hinge brake rod connected to the brake pedal and a second imaginary plane across the cam lever connected to the rear wheel. If the brake rod is straight, the lateral offset would be zero. Having zero lateral offset severely affects the braking performance of the entire brake assembly. Due to layout constraints, the hinge brake rod connected to the brake pedal and the cam lever do not have minimum lateral offset which results in poor braking performance of the brake assembly.
[00024] Therefore, in order to overcome the above-mentioned problems of layout constraints and having minimum lateral offset between the hinge brake rod connected to the brake pedal and the cam lever connected to the rear wheel, brake rods, typically, have a minimum of two bends, which is required for the brake rods to effectively connect the brake pedal to the cam lever. The first bend is at a front portion of the brake rod, near to the brake hinge. The second end is at a rear portion of the brake rod. The brake hinge brake and the brake rod are aligned along the same axis until the first bend in the brake rod. Having two bends in a single brake rod, results in decreased stiffness of the brake rod, thereby resulting in inaccurate application of brakes due to spongy feeling.
[00025] Moreover, the bending angle corresponding to the minimum two bends in such brake rods needs to be within a predetermined range in order to avoid structural deformation of the brake rods as the brake rods are made of thin sheet metal due to packaging constraints.
[00026] Also, using a longer brake rod with more bending angle will result in elongation of the entire brake assembly, thereby resulting in increased length of the vehicle in the longitudinal direction of the vehicle when viewed from front-rear side.
[00027] Such bends in the brake rod results in low stiffness of the brake rod. This low stiffness ultimately leads to a spongy feel in the rear brake application. Attempts have been made in the past to solve the problem of stiffness of brake rod by increasing the diameter of such brake rod, however, it does not solve the problem of spongy feeling while the brakes are applied. Moreover, this increases the chances of structural deformation of the brake rod due to low stiffness of the brake rod. Further, brake rods with increased thickness and diameter results in increased weight of the vehicle, thereby ultimately increasing the entire cost of the vehicle which is not desirable.
[00028] Thus, the present subject matter aims to provide a light-weight, improved brake rod with increased section modulus that meets the layout constraints, thereby enhancing the stiffness of the brake assembly and eliminates the spongy feeling while the rear brakes are applied.
[00029] It is an aim of the present subject matter to provide an improved braking performance such that the braking rod has enhanced bending stiffness and improved area of cross section at the bends in the brake rod.
[00030] The present subject matter along with all the accompanying embodiments and their other advantages would be described in greater detail in conjunction with the figures in the following paragraphs.
[00031] According to a preferred embodiment of the present subject matter, a brake assembly in a two-wheeled vehicle is disclosed. The brake assembly comprises a brake hinge and a brake rod. A first end of the brake rod is inserted into the brake hinge. A second end of the brake rod is connected to a rear wheel of the two-wheeled vehicle. Further, the brake rod has a primary bend at a rear portion of the brake rod. This primary bend is enclosed by a sleeve. The brake hinge further has a secondary bend at one end of the brake hinge. Here, the primary bend and secondary bend is capable of increasing sectional modulus of the brake rod to provide increased stiffness to the brake rod at load-bearing portions of the brake rod.
[00032] In another embodiment, the primary bend in the brake rod is provided at a predetermined distance of 110mm-120mm from the second end of the brake rod.
[00033] In yet another embodiment, the sleeve is having a longitudinal length of 28mm-30mm.
[00034] In another embodiment, the sleeve is of cylindrical shape.
[00035] In an embodiment, the sleeve is made up of a metal.
[00036] In another embodiment, the secondary bend provides a predetermined angular offset (T) between an imaginary brake hinge axis passing through a center of the brake hinge and an imaginary brake rod axis passing through a center of the brake rod.
[00037] The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[00038] The brake assembly may be implemented in any type of vehicle. However, for the purpose of explanation and by no limitation, the brake assembly, and corresponding additional advantages and features are described through the following embodiments. Arrows wherever provided on top right corner of the figure represent direction with respect to vehicle. Arrow F represents forward direction, arrow R represents rearward direction, arrow UW represents upward direction and arrow DW represents downward direction.
[00039] Fig. 1 illustrates a right-side view of an exemplary two-wheeled vehicle 100. The two-wheeled vehicle 100 comprises a main frame 101 having a head tube 102. Towards front side, the two-wheeled vehicle 100 has one or more front suspensions 104 connected to a front wheel 106 which is further connected to a handlebar assembly 108, which forms a steering assembly of the two-wheeled vehicle 100. The steering assembly has a pair of rear-view mirrors 112a, 112b. The steering assembly is rotatably disposed about the head tube 102. The main frame 101 extends rearwardly downward from the head tube 102 and has a bent portion thereafter extending substantially in a longitudinal direction.
[00040] The motor vehicle 100 further has an internal combustion (IC) engine 120. In the present embodiment, the IC engine 120 is swingably connected to the main frame 101. Towards rear side, the two-wheeled vehicle 100 has a rear wheel assembly 124 connected to one or more rear suspensions 122. The rear wheel assembly 124 has a rear wheel 110 mounted on a wheel rim 126. The two-wheeled vehicle 100 also has an exhaust system 130 extending rearwards from the IC engine 120. In addition, the vehicle 100 has a rear fender 132 covering at least a portion of the rear wheel 110 and is positioned upwardly of the rear wheel 110.
[00041] Further, the two-wheeled vehicle 100 has a seat assembly 135 supported by the main frame 101. The seat assembly 135 is hingedly openable. The two-wheeled vehicle 100 has a floorboard 137 wherein a rider can operate the two-wheeled vehicle 100 in a seated position by resting feet on the floorboard 137. Further, the floorboard 137 is capable of carrying loads. In addition, a utility box is disposed below the seat assembly 135 and is supported by the main frame 101. A fuel tank (not shown) is disposed adjacent to the utility box. Furthermore, the two-wheeled vehicle 100 comprises of plurality of electrical and electronic components including a headlight assembly (not shown), a taillight assembly (not shown), a transistor-controlled ignition (TCI) unit (not shown), an alternator (not shown), a starter motor (not shown). The two-wheeled vehicle 100 is thus made to stay in a riding ready position over a center stand (not shown).
[00042] For brevity purposes, Fig.2(a), 2(b) and 2(c) will be explained together. Fig. 2(a) illustrates a left side view of a brake rod in accordance with an embodiment of the present subject matter. Fig. 2(b) illustrates a bottom view of the brake rod in accordance with an embodiment of the present subject matter. Fig. 2(c) illustrates a sectional bottom view of the brake rod in accordance with an embodiment of the present subject matter. A brake rod assembly 200 having a brake hinge 205 connected to a brake rod 210 is disclosed. The brake rod has a first end which is inserted into the brake hinge 205 and a second end connected to a rear wheel 110 of the two-wheeled vehicle 100. The brake hinge 205 is attached to a brake pedal where the user of the two-wheeled vehicle 100 applies force to initiate the braking action. Further, the brake rod 210 has a primary bend 215 (as shown in Fig. 2(c)) at a rear portion of the brake rod 210. This primary bend 215 is enclosed by the metal sleeve 220, preferably made of aluminium. The brake hinge 205 includes a secondary bend 225 at one end of the brake hinge 205.
[00043] Here, the primary bend 215 and secondary bend 225 together achieves increased sectional modulus of the brake rod 210 to provide increased stiffness to the brake rod 210 at load-bearing portions of the brake rod 210.
[00044] Referring to Fig. 2(c), Fig. 3(a), Fig. 3(b) Fig. 4(a) and Fig. 4(b), a secondary bend 225 is incorporated in one end of the brake hinge 205 where the brake rod 210 is inserted into the brake hinge 205. A predetermined angular offset T equal to ~8° between an imaginary brake hinge axis XX passing through a center of said brake hinge 205 and an imaginary brake rod axis YY passing through a center of said brake rod 210 is achieved, which helps in eliminating an additional bend in the brake rod 210. Herein, a bend is provided in the brake hinge 205 instead of having two bends in the brake rod as disclosed in the existing art.
[00045] Herein, the brake hinge 205 is a hollow member. Having the secondary bend 225 in the brake hinge 205 provides increased section modulus to the hollow brake hinge 205 as compared to a solid brake hinge 205. Therefore, the brake hinge 205 is capable of bearing load applied by the user of the vehicle 100 and thus prevents structural deformation of the brake assembly 200. Thus, the secondary bend 225 also provides increased stiffness to the brake assembly 200.
[00046] Thus, the present subject-matter disclosing the brake rod 210 has a single primary bend 215 as compared to the existing state-of the-art that comprises of two bends in the brake rod. Therefore, elimination of one bend in the brake rod, results in significant increase in stiffness of the brake rod 210.
[00047] Referring to Fig. 5(a) and Fig. 5(b), the brake rod 210 has the sleeve 220 which is of a cylindrical shape before it is assembled to the brake rod 210. This sleeve 220 is then inserted into the brake rod 210 and welded after fixing it in the required position. Then the brake rod 210 is bent along with the sleeve 220 to provide the required intended bending in brake rod 210. The addition of sleeve 220 around the primary bend 215 in the brake rod 210 provides added stiffness around the primary bend 215. This helps the brake rod 210 in retaining the adequate stiffness in order to perform the required braking function. Also, the placement of the sleeve 220 does not disturb the layout constraints in the vehicle 100.
[00048] Herein, the sleeve 220 improves the section modulus of the brake rod 210, thereby increasing the bending stiffness of the brake rod 210. Since the brake rod 210 has increased bending stiffness, this results in eliminating the problem of structural deformity of the brake rod 210 due to excessive load on the brake assembly 200, without increasing the weight of the brake rod 210. It has been observed that the present subject matter increases the stiffness of the brake rod by 14-15% due to presence of the sleeve and bend in the brake hinge 205.
[00049] Thus, the proposed subject matter eliminates one bend out of two bends from the existing brake rod design which caused the spongy brake feel problem. The addition of sleeve also provides the added stiffness around the only bend. It improves sectional modulus locally wherever bending load acting. These two factors combined together eliminate the spongy brake feel issue without disturbing the layout constraints.
[00050] It provides a cost-effective brake rod with minimum weight due to utilization of aluminum sleeves that serves a dual purpose of increasing the stiffness of the brake rod, without increasing the thickness of the brake rod. Since, the thickness of brake rod remains the same, the brake rod is lighter in weight. Such brake rod also meets the lateral offset requirements to provide minimum operating clearance to the brake assembly to operate without rubbing the other parts of the vehicle. This results in easy actuation of th brake assembly and thereby improves the braking performance of the vehicle.
[00051] While certain features of the claimed subject matter have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the claimed subject matter.


List of reference signs:
100 two-wheeled vehicle
101 main frame
102 head tube
104 front suspensions
106 front wheel
108 handle bar assembly
110 rear wheel
112a, 112b rear view mirrors
120 internal combustion engine
122 rear suspensions
124 rear wheel assembly
126 wheel rim
130 exhaust system
132 rear fender
135 seat assembly
137 floorboard
200 brake assembly
205 brake hinge
210 brake rod
215 primary bend
220 sleeve
225 secondary bend
XX Imaginary hinge axis
YY Imaginary brake rod axis
T Angular offset
,CLAIMS:We claim:
1. A brake assembly (200) in a two-wheeled vehicle (100), said brake assembly (200) comprising:
a brake hinge (205); and
a brake rod (210), wherein a first end of said brake rod (210) being inserted into said brake hinge (205) and a second end of said brake rod (210) being coupled to a rear wheel (110) of said two-wheeled vehicle (100);
wherein said brake rod (210) includes a primary bend (215) at a rear portion of said brake rod (210), said primary bend (215) being enclosed by a sleeve (220); and
wherein said brake hinge (205) includes a secondary bend (225) at one end of said brake hinge (205);
wherein said primary bend (215) and secondary bend (225) being capable of increasing sectional modulus of said brake rod (210) to provide increased stiffness to said brake rod (210) at load-bearing portions of said brake rod (210).

2. The brake assembly as claimed in Claim 1, wherein said primary bend (215) in said brake rod (210) being provided at a predetermined distance of 110mm to 120mm from said second end of said brake rod (210).

3. The brake assembly as claimed in Claim 1, wherein said sleeve (220) having a longitudinal length of 28mm to 30mm.

4. The brake assembly as claimed in Claim 1, wherein said sleeve (220) being of cylindrical shape.

5. The brake assembly as claimed in Claim 1, wherein said sleeve (220) being of a metal.

6. The brake assembly as claimed in Claim 1, wherein said secondary bend (225) provides a predetermined angular offset (T) between an imaginary brake hinge axis (XX) passing through a center of said brake hinge (205) and an imaginary brake rod axis (YY) passing through a center of said brake rod (210).