WO2022201182A1

WO2022201182A1 - Compound braking system of a vehicle

Info

Publication number: WO2022201182A1
Application number: PCT/IN2022/050191
Authority: WO
Inventors: Shanmugam MOHAN; Karanam VENKATA MANGA RAJU
Original assignee: Tvs Motor Company Limited
Priority date: 2021-03-23
Filing date: 2022-03-03
Publication date: 2022-09-29

Abstract

The present invention relates to a compound braking system of a vehicle (100) comprising a master cylinder (300) including a primary piston (302), and a secondary piston (305). The primary piston (302), the primary piston (302) housed in a primary master cylinder bore (304); and the secondary piston (305), including a first protrusion (310). A rear brake cable (308) and the first protrusion (310) are configured to create a first connection (309). The compound braking system enables connection of the rear brake cable (308) of the rear brake to the front braking system directly, thereby actuating of both front braking and rear braking during the synchronous braking or combined braking without disturbing the independent functioning of the front brake actuation lever (208) during only front braking.

Description

COMPOUND BRAKING SYSTEM OF A VEHICLE

TECHNICAL FIELD

[0001] The present subject matter described herein generally relates to a vehicle, and particularly but not exclusively relates to a compound braking system of a vehicle.

BACKGROUND

[0002] In the last few decades, two-wheeler automobile industry has shown a remarkable growth and development, in terms of technology as well as usage. Due to consistent advancement in technology, two-wheeled vehicles, such as bicycles, motorcycles, scooters and light-weight scooters, have succeeded in maintaining their popularity among different sections of society. Different sections of society, based on their requirement, utilize the two-wheeled vehicles for various purposes, such as a recreational activity, a means of transportation, and for sports activities. As a result, it becomes pertinent for the two-wheeler automobile industry to constantly develop and design the components of the two wheeled vehicles to suit requirements of different riders.

[0003] Generally, two-wheeled vehicles are provided with a pair of mechanically operated drum brakes. However, with the advent of braking technology, hydraulically operated drum brakes and disc brakes have come to use. Also, in some applications disc brake is installed on both front and rear wheels. Typically, two-wheeled vehicles with disc brakes installed only on to front wheels are most commonly used. However, such a determination of whether to use two disc brakes or one disc brake is primarily based on the capacity of the vehicle and the maximum load capable of being carried by the vehicle. Generally, for lesser capacity vehicles that are not expected to reach very high speed levels, a single disc brake is provided, preferably, on to the front wheel of the vehicle.

[0004] In accordance with the aforementioned ideology, various types of braking systems have been developed for facilitating braking functionalities in the two-wheeled vehicles. Conventionally, braking systems that allow simultaneous actuation of a front brake and a rear brake upon application of a single brake lever have gained widespread popularity across the globe. Such, simultaneous actuation of the front wheel brake and the rear wheel brake is performed by a braking system.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The detailed description is described with reference to an embodiment of a saddle type two wheeled scooter along with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.

[0006] Figure 1 illustrates a side view of a vehicle, for example a two wheeled vehicle, when viewed from left hand side of the rider while the rider is in riding position.

[0007] Figure 2 illustrates a sectional view of a standard front master cylinder of a vehicle.

[0008] Figure 3a to Figure 3c illustrates a sectional view of a front master cylinder of a vehicle in a non-operative condition, in accordance with an embodiment of the present claimed subject matter.

[0009] Figure 4a to Figure 4c illustrates a sectional view of a front master cylinder of a vehicle during operation of only front braking by means of a front brake actuation lever, in accordance with an embodiment of the present claimed subject matter.

[00010] Figure 5a to Figure 5c illustrates a sectional view of a front master cylinder of a vehicle during operation of only rear braking by means of a rear brake control lever (not shown), in accordance with an embodiment of the present claimed subject matter. [00011] Figure 6a to Figure 6c illustrates a sectional view of a front master cylinder of a vehicle during operation of both front braking and rear braking by means of a rear brake control lever (not shown), in accordance with an embodiment of the present claimed subject matter.

[00012] Figure 7a to Figure 7b illustrates a sectional view of a secondary master cylinder bore of a front master cylinder of a vehicle, in accordance with an embodiment of the present claimed subject matter.

[00013] Figure 8a to Figure 8c illustrates a schematic sectional view of a secondary master cylinder bore of a front master cylinder of a vehicle, in accordance with an alternate embodiment of the present claimed subject matter.

DETAILED DESCRIPTION

[00014] Conventionally, two- wheeled vehicles, similar to any motor vehicles, are provided with a braking system for slowing or stopping the vehicle. The braking system, usually, includes at least one brake assembly, such as a front wheel brake assembly and a rear wheel brake assembly for a front wheel and a rear wheel, respectively. Such brake assemblies may include, but are not limited to a cam lever, a cam pin, and a pair of friction liners/brake shoes or a brake caliper with frictional pads, and a brake disc. Further, each of the front wheel brake assembly and the rear wheel brake assembly is connected to a brake lever for actuation. For example, the brake lever may be coupled to a pair of friction liners/brake shoes for applying friction to each wheel of the two- wheeled vehicle, as and when the brake lever is actuated.

[00015] The brake lever can be connected to the brake assembly in a variety of ways. For example, the brake lever can be connected to the brake assembly by means of a cable. In such a case, one end of the cable may be secured to the brake assembly, and the other end of the cable may be secured to the brake lever. In another case, the brake lever can be connected to the brake assembly through a hydraulic means. This is generally applicable for disc brakes. Consequently, actuation of the brake lever may result in actuation of the brake assembly and subsequently, the brake may be applied.

[00016] Generally, the front wheel and the rear wheel are provided with separate compound braking systems. Conventional two- wheeler and three-wheeler braking systems usually include either hand-operated brakes for both the wheels or include a combination of hand-operated and foot-operated brakes. In the latter case, generally, the front wheel brakes are hand-operated, and include a front brake lever mounted on a handle of the two-wheeled vehicle for actuation, whereas the rear wheel brakes can be foot-operated by a synchronous brake lever provided near a foot-rest of the rider.

[00017] Usually, during operation of the brakes, riders tend to apply the rear wheel brake alone. Such a practice stems from the fact that actuating both the brake levers at the same time may be inconvenient for the rider. In addition, when the front wheel brake is applied, with fewer loads on the front wheel prior to braking and sudden weight transfer towards the front wheel, it causes the front wheel to brake rapidly, and may result in a sudden jerk to the vehicle. The sudden jerk may affect the ride quality and may disturb the balance and stability of the vehicle leading to an accident. However, on the other hand, the braking force applied for braking the rear wheel may have to be limited, to prevent skidding of the vehicle. As a result, the deceleration experienced by the vehicle may also be limited and subsequently, the stopping distance of the vehicle may be significantly large.

[00018] Conventionally, in order to address the above-mentioned concerns, braking systems that allow simultaneous actuation of a front brake and a rear brake by application of a single brake lever have been developed. Such braking system are capable of uniting the braking operation of both the front wheel brake and the rear wheel brake with the help of a single brake lever, for example the synchronous brake lever. Accordingly, upon actuation of the single brake lever, such a braking system may allow distribution of braking force to the front wheel as well as the rear wheel of the vehicle. Therefore, the front wheel brake and the rear wheel brake can be simultaneously applied by actuating one brake lever, for example, the synchronous brake lever. In addition to being convenient for the rider, such braking systems may ensure that the deceleration of the vehicle can be increased and subsequently, the stopping distance may be reduced. Further, as would be understood, in two-wheeled vehicles with such braking systems, a front brake lever may also be provided to independently operate the front wheel brake.

[00019] Further, in such braking systems, each cable from each of the front brake lever and the synchronous brake lever may be connected to the front wheel brake assembly as the front wheel brake assembly is operated by application of either of the brake levers. Furthermore, in vehicles with front wheel brake assembly being a disc brake type, a hydraulic fluid dispensing member is mounted in the vicinity of the front brake lever for actuating a hydraulically operated disc brake. This enables the front brake lever to actuate the hydraulic fluid dispensing member for dispensing requisite amount of hydraulic fluid whenever front wheel brake is applied. Also, while actuating the front wheel brake by means of the synchronous brake lever in such braking systems, it is essential to actuate the hydraulic fluid dispensing member. Hence, in order to actuate the hydraulic fluid dispensing member when the synchronous brake lever is applied, a cable from the synchronous brake lever is connected to the hydraulic fluid dispensing member.

[00020] However, braking systems that allows simultaneous actuation of a front brake and a rear brake by application of a single brake lever having a front disc brake known in the prior art has several limitations.

[00021] Some such limitations include usage of plurality of levers, commonly called as knockers to actuate at least one end of the piston placed in a front brake master cylinder to actuate front braking while using synchronous braking. Synchronous braking allows actuation of both front and rear brakes simultaneously by means of a single lever, usually a rear brake lever. However, upon the application of the rear brake lever, the force is automatically transmitted to an additional knocker or a lever placed in close contact of the piston of the front brake master cylinder, in the vicinity of the front brake lever, thereby actuating the front braking. Usually, such additional levers or knockers are capable of being independently controlled.

[00022] Because of the presence of the additional lever in the vicinity of the front brake lever, in such brake systems, certain measures need to be taken to avoid the interaction of the synchronous braking with the independent functioning of the front brake lever.

[00023] Some known arts disclose about keeping the pivotal axis of the one or more additional levers or knockers used to actuate front brake during a synchronous braking, common to the front brake lever.

[00024] However, since the front lever is movable towards the rider when viewed from a rider’s perspective, providing of such additional levers or knockers often creates packaging constraints. Mostly because, ergonomically a minimum clearance is required to be provided to ensure easy stroking of the front brake lever. Therefore, providing of any additional lever or knocker in the clearance area, acts as a hindrance for the rider while stroking the front brake lever. Also, in many vehicles, the area near the front brake lever is more tightly packaged because of the additional switch controls provided on the front panel of the vehicle, near the handle bar assembly. Presence of such additional switch controls further ads up to the packaging constraints.

[00025] Other known arts disclose about shifting of the pivotal axis of the one or more additional levers or knockers, away from the pivotal axis of the front brake lever. But, in such scenarios, the one or more additional levers or knockers need to be placed parallel to the front brake lever, in order to apply optimum contact pressure on the piston. Therefore, the parallel placement of the additional levers or knockers further increases packaging constraint with respect to the front brake lever. [00026] Hence, there is a need of an improved and compact compound braking system of a vehicle that is capable of providing independent functioning of the synchronous braking by using rear brake lever, while eliminating the interference of the front brake lever. Also, there is a need of eliminating the one or more additional knockers or levers which are generally used to actuate the front braking during the application of the simultaneous braking, to ensure elimination of the packaging constraints posed by the usage of one or more additional knockers or levers.

[00027] Moreover, during synchronous braking the force applied on the rear brake lever is relayed to the piston of the front brake master cylinder, by means of an additional knocker or lever placed in the vicinity of the front brake lever. As a result, a considerable length of cable is required to connect the additional lever or knocker with the rear brake lever, usually following a complex cable routing, all across from the left-hand side of the vehicle to the right-hand side of the vehicle, where the additional lever or knocker is placed.

[00028] The present subject matter has been devised in view of the above circumstances as well as solving other problems of known art.

[00029] The present subject matter is a compound braking system of a vehicle, which is designed to enable connection of the control cable of the rear brake to the front braking system directly, thereby actuating both front braking and rear braking during the synchronous braking or combined braking without disturbing the independent functioning of the front brake actuation lever.

[00030] As per an aspect of the present subject matter, the present subject matter includes a compound braking system of a vehicle configured with a front master cylinder assembly (300) for a disc brake. The front master cylinder assembly comprises of a primary piston, a secondary piston, and a front brake actuating lever to actuate the front braking. The primary piston is enclosed within a primary space, for example, a primary master cylinder bore. The secondary piston includes a protruded part. A part of secondary piston is enclosed within the primary master cylinder bore and the protruded part of the secondary piston is enclosed within a secondary space, for example a secondary master cylinder bore. A cable being directly attached to a member further operably connected to the secondary piston and the cable pulls the secondary piston and actuates the braking system of the vehicle by an inward movement in a direction operably away from the front brake actuation lever of the braking system of the vehicle.

As per another aspect of the present embodiment, a method of application of front brake via actuation of a rear brake force for a compound combined braking system of a vehicle comprising a front disc brake, a rear drum brake. The method consisting of: actuating a rear brake lever in a direction towards a rider; relaying of actuated force from said rear brake lever to the protruded part of the secondary piston housed in the secondary space of a master cylinder assembly, through a cable attached to the secondary piston; pulling of the secondary piston and the primary piston housed in a primary space of a master cylinder assembly, inwardly in a direction operably away from a front brake actuation lever by means of the protruded part of the secondary piston housed in the secondary master cylinder bore, thereby creating a working clearance between the primary piston and the front brake actuation lever; creating a pressure difference between the primary space and the secondary space; transmitting of brake fluid through a brake caliper and a hose from the primary master cylinder bore to front wheel disc brake; and braking of a front wheel of a vehicle by means of the front wheel disc.

[00031] As per another aspect of the present embodiment, the primary piston being housed in a primary master cylinder bore and the secondary piston being partially housed in the primary master cylinder bore and partially housed in a secondary master cylinder bore.

[00032] As per another aspect of the present subject matter, the secondary piston extends as a first protrusion. The first protrusion is configured to create a first connection. [00033] As per another aspect of the present subject matter, the first connection is formed between the first protrusion of the secondary piston and the first coupling member in the secondary master cylinder bore by means of a locking or coupling means. The locking or coupling means include a collar pin or a lock pin.

[00034] As per another aspect of the present subject matter, a banjo joint is disposed on a lateral wall of the front master cylinder and a master cylinder return spring is wounded over the secondary piston. One end of the master cylinder return spring is connected to a secondary piston seal disposed at one end of a primary piston. The other end of the master cylinder return spring is connected to a tertiary piston seal disposed at one end of a primary master cylinder bore in the direction away from the primary piston.

[00035] As per another aspect of the present subject matter, the primary piston is sealed on both ends by means of a primary seal and a secondary seal.

[00036] As per an alternate embodiment of the present subject matter, the secondary piston is an extension of the primary piston, wherein the secondary piston is integrated to the primary piston.

[00037] As per an aspect of the present subject matter, the braking system of a vehicle is housed in a master cylinder housing.

[00038] As per an aspect of the present subject matter, the primary master cylinder bore and the secondary master cylinder bore has an area difference. This area difference aids in creation of pressure difference between the both the primary master cylinder bore and the secondary master cylinder bore.

[00039] As per an alternate embodiment of the present subject matter, the secondary piston is concentric with the secondary master cylinder bore.

[00040] As per an alternate embodiment of the present subject matter, the primary master cylinder bore is concentric with the secondary master cylinder bore. [00041] The nature and further characteristic features of the present invention will be made clearer from the following descriptions made with reference to the accompanying drawings.

[00042] Exemplary embodiments detailing features regarding the aforesaid and other advantages of 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 invention. Further, it is to be noted that terms “upper”, “down”, “right”, “left”, “front”, “forward”, “rearward”, “downward”, “upward”, “top”, “bottom”, “exterior”, “interior” 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, arrows wherever provided in the top right corner of figure(s) in the drawings depicts direction with respect to the vehicle, wherein an arrow F denotes front direction, an arrow R indicates rear direction, an arrow Up denotes upward direction, an arrow Dw denotes downward direction, an arrow RH denotes right side, and an arrow FH denotes left side. 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.

[00043] Figure 1 illustrates a side view of a vehicle (100), for example a two wheeled vehicle with certain interior parts shown for clarity, when viewed from left hand side of the rider while the rider is in riding position. The vehicle (100) is generally provided with a power assembly (not shown) that generates the power required to propel the vehicle forward. A frame assembly (102), which further includes a front frame (not shown), a central frame (not shown) and a rear frame (not shown) joined together to form the frame assembly (102). A power transmission assembly (106), which transfers the power generated by the power assembly (not shown) to the rear wheel (107), and a front wheel (108) at front portion of the vehicle below the front frame which is steerable by the rider, and a pair of handle bar assembly (109) comprising of a left handle bar grip (110) and a right handle bar grip (not shown) and a throttle assembly (not shown) which the rider can use to steer the front wheel (108) in the desired direction. A front suspension assembly (112) is used for smooth force transmission to the front wheel (108), and a rear suspension assembly (not shown for smooth force transmission to the rear wheel (107).

[00044] The front frame includes a head tube (not shown) and a down tube ( not shown); the head tube supports the front suspension assembly (112), which further supports the pair of handle bars as a handle bar assembly (109) in a steerable manner and the down tube extends rearward and downward of the head tube . The central frame has two tubes (not shown) on the left and right of the vehicle (100) extending away from each other in a rearward direction. The left and right tubes are connected by one or more cross frame (not shown) extending in vehicle width direction. These left and right tubes further extend rearward and upward to form the rear frame, which supports other assemblies of the vehicle at rear portion.

[00045] A front panel (116) is provided ahead of the head tube for covering the head tube when viewed from front of the vehicle (100). A rear panel (133), extending downwards from the head tube, covers the head tube and down tube from the rear side. A front fender (119) is provided above the front wheel (108), in the vicinity of the front suspension assembly (112), to prevent mud splashing onto the internal articles of the vehicle at the front portion. A handle bar rear panel (134), at least partly covers the pair of handle bars (109), from the rear side. A handle bar front panel (121) at least partly covers the pair of handle bars (109) from front side. A glove box (118) is mounted on the rear panel (135), below the handle bar rear panel (134) and above the floor board (124). A headlamp assembly (122) is disposed on the handle bar front panel (121) and pair of mirrors (123) is disposed on the handle bar assembly (109) through the handle bar front panel (121). An interfacing portion of the handle bar front panel (121) and the handle bar rear panel (134) has a cut-out zone (not shown) on left side and right side for projecting the left handle bar grip (110) and right handle bar grip (not shown) respectively. A floor board (124) as a leg resting panel is provided above the central frame to cover a top portion of the central frame and a bottom panel (125) is provided below the central frame to cover a bottom portion of the central frame.

[00046] On the rear side, a utility unit (126) is disposed, at the space between the left and right tubes at the rear portion of the vehicle (100) above the power unit (not shown, to store articles. The utility unit (126) is mounted onto the cross tube at the front portion and rear portion, thus getting supported by the rear frame. A seat unit (127) is provided, above the utility unit (126) and extending throughout the rear frame, for the rider to sit over and maneuver the vehicle (100). The seat unit (127) is mounted onto the vehicle through a hinge unit (128), provided on the utility unit (126), such that the seat can be opened by rotating it about the hinge unit (128) to provide access to the storage area (129) of the utility unit (126).

[00047] A side panel LH (130) is provided on the left side of the rear frame and a side panel RH (not shown) is provided on the right side of the rear frame so as to cover the internal components when viewed from left and right sides of the vehicle (100) respectively. A front cover (131) is disposed ahead of the utility unit (126) and below the seat unit (127) to cover the internal components, such as the power assembly (not shown), frame assembly (102) in a vehicle perspective view. A rear cover (132) is provided rearward to the rear frame and an opening, formed by assembling the rear cover (132) and the side panel assembly (130, 132), is used to place a tail lamp (117) on the rear side. A rear fender (120) is disposed above the rear wheel (107) to prevent mud splashing onto internal components while riding. A grab rail (111) is disposed in the vicinity of the seat unit (127), on the rear portion of the vehicle (100), to enable a pillion rider to grab for support.

[00048] Figure 2 illustrates a sectional view of a standard front master cylinder (200) of a vehicle (100) as per known art. A standard front master cylinder (200) of a vehicle (100) is located on a handle bar assembly (109). A front brake actuation lever (208) is pivotally connected to the standard front master cylinder

(200) on one end of the front brake actuation lever (208). The other end of the front brake actuation lever (208) is capable of free movement towards the rider, when viewed from a rider sitting on the vehicle (100) while driving. The standard front master cylinder (200) includes a master cylinder housing (210), and comprises of a piston (207) disposed in a master cylinder bore (204), a primary piston seal (205), a secondary piston seal (206) and a master cylinder return spring (203). Further, standard front master cylinder (200) includes a brake fluid reservoir

(201), disposed above the master cylinder bore (204). The brake fluid reservoir (201) stores the brake fluid. The brake fluid reservoir (201) is connected to the master cylinder bore (204) by means of a primary orifice (209a) and a secondary orifice (209b). The master cylinder bore (204) is further sealed and connected on the other end of the standard front master cylinder (200) to a brake caliper by means brake hose (212) through a banjo joint (202).

[00049] A master cylinder return spring (203) is connected on one end of the piston and the other end is connected to the cylinder bore of the master cylinder assembly. A hydraulic port (not labeled) is connected to the other end of the system, which hydraulically connects the brake hose (212). The piston (207) is further sealed on both ends by means of a pair of seals, i.e., a primary piston seal (205) and a secondary piston seal (206).

[00050] The front brake actuation lever (208) is actuated, i.e., pressed towards the rider in scenarios where braking is required by the rider while driving. Resultant to which the front brake actuation lever (208) pushes one end of a piston (207), towards the inside of master cylinder bore (204), which is subjected to hydraulic pressure because of the brake fluid present in the space in vicinity of the piston (207). Therefore, when the piston (207) is actuated by means of the front brake actuation lever (208), it compresses the hydraulic fluid present inside the front brake master cylinder (200), which results in force transfer to the brake caliper through the movement of the hydraulic fluid stored in the brake fluid reservoir (201) towards the master cylinder bore (204) by means of the primary orifice (209a), which is further pushed towards a brake hose (211) hydraulically connected to the front brake master cylinder (200) by means of the banjo joint (202).

[00051] Upon release of the front brake actuation lever (208), the master cylinder return spring (203) present in between the piston (207) and one end of the master cylinder bore (204), aids in return of the piston (207) back to its original position.

[00052] The primary orifice (209a) allows movement of the braking fluid into the master cylinder bore (204). There other opening that is, the secondary orifice (209b) provides lubrication to the members present in between the two seals, i.e., the primary piston seal (205) and a secondary piston seal (206), to prolong the wear and tear of the internal elements.

[00053] The primary piston seal (205), for example a cup seal, is usually subjected to high pressure because of the direct engagement with the brake fluid and most of the elements present in the master cylinder bore (204). However, the secondary piston seal (206) is used as a supporting element that aids in sealing the fluid to any avoid leakage. The two seals, i.e., the primary piston seal (205) and a secondary piston seal (206) together provide lateral sealing stability to the whole braking system.

[00054] In some known arts, where a synchronized braking system or combined braking system, is used along with independent front brake systems, usually additional lever or knocker (not shown) is used along with front lever. In such known arts during the application of the synchronized braking or compound braking system, the piston (207) is actuated by the front brake actuation lever (208) and the additional lever or knocker (not shown).

[00055] Figure 3a to Figure 3c illustrates a sectional view of a master cylinder (300) of a vehicle (100), for example a front master cylinder assembly (300), in non-operative condition (300), in accordance with an embodiment of the present claimed subject matter. The proposed compound master cylinder (300) for a disc brake system of a vehicle (100) comprises of a master cylinder assembly (300), for example a front master cylinder assembly (300) includes an actuation lever (208), for example, afront brake actuation lever (208). The front master cylinder (300) further includes a brake fluid reservoir (201), a primary piston (302), a secondary piston (305), a primary space (304), for example a primary master cylinder bore (304), a secondary space (303), for example, a secondary master cylinder bore (303), a lock pin (307) or a collar pin (314) (shown in Fig. 10a) and a first connection (309). The secondary master piston (305) is extended away from the primary cylinder in the secondary master cylinder bore (303) to form a first protrusion (310). Therefore, the secondary master piston (305) includes the first protrusion (310). The first protrusion (310) is configured with a first connection (309) between rear brake system and front brake system.

[00056] The primary piston (302) is pivotally connected on one end to a front brake actuation lever (208) and the other end of the primary piston (302) is extended as the secondary piston (305). As per an embodiment the secondary piston (305) is a separate part. As per another embodiment, the secondary piston (305) is integrated to the primary piston (302). Both the primary piston (302) and the secondary piston (305) are disposed in the primary master cylinder bore (304). The extended portion of the secondary piston (305) that is the first protrusion (310) is disposed in the secondary master cylinder bore (303).

[00057] The primary piston (302) is sealed on both ends by means of a primary seal (206) and a secondary seal (205). A master cylinder return spring (203) is wounded over the secondary piston (305), such that one end of the master cylinder return spring (203) abuts the secondary piston seal (206) disposed on one end of the primary piston (302). The other end of the master cylinder return spring (203) abuts a tertiary piston seal (301) disposed on one end of the primary master cylinder bore (304) in the direction away from the primary piston (302). As per an embodiment, at least one of the primary piston seal (205), the secondary piston seal (206), and/or the tertiary piston seal (301) is a cup seal type of seal.

[00058] The primary piston (302), the secondary piston (305) and the master cylinder return spring (203) together form a new hydraulic guiding means for the front master cylinder (300).

[00059] One end of the secondary piston (305), which is away from the primary piston (302), extends or protrudes out as a first protrusion (310) in a secondary master cylinder bore (303). The first protrusion (310) is opposite to front brake actuation lever (208), and beyond the front master cylinder (300) and the hydraulic guiding means. The first protrusion (310) is operably connected to the secondary master cylinder bore (303) by means of one or more locking or coupling means, for example, a lock pin (307).

[00060] A rear brake cable (308) of a rear brake control lever (not shown), is directly connected to a first coupling member (315), which is further connected to at least one end of the first protrusion (310) of the secondary piston (305), by means of a first connection (309). The banjo joint (202) of the brake caliper is disposed on a lateral wall of the front master cylinder (300).

[00061] Unlike the known arts, where during synchronous braking or combine braking, the piston (207) is actuated by the front brake actuation lever (208) and the additional lever or knocker (not shown), In the present subject matter, the piston (302) (herein a primary piston ) is pulled from the other side by means of the secondary piston (305) owing to the direct connection between the primary (302) and secondary pistons (305) and through a first connection (309), sheath (306)which is being actuated by means of the rear brake cable (308) of the rear brake lever. The secondary piston (305) being coupled by means of lock pin (307) via a first coupling member (315) to the rear brake cable (308). Thereby, during the synchronous braking or combine braking, in the present proposed subject matter, the front brake actuation lever (208) is not disturbed, keeping the front brake actuation lever (208) function intact, independent from the synchronous braking or combined braking.

[00062] The first connection (309) is shown by dotted circle in Fig. 3 b. During non-operable condition, a clearance of distance D3 is provided between at least an innermost part of the secondary master cylinder bore (303) and the first coupling member (315), which is further connected to at least one end of the first protrusion (310) of the secondary piston (305), by means of a first connection (309) of the front brake master cylinder (300).

[00063] In the present illustration (Fig. 3b), the length of the primary piston (302) is shown as Dl, the length of the secondary piston (305) is shown as D2. D4 is the length of the first protrusion (310) of the secondary piston (305).

[00064] Moreover, a first joint (211) aids in holding the front brake actuation lever (208) in position, even during the non-operable condition of the front master cylinder assembly (300) and creation of a clearance between the primary piston

(302) and the front brake actuation lever (208), because of the inside movement of the primary piston (302). Therefore, the first joint (211) holds the front brake actuation lever (208) in position, ensuring avoidance of any rattling noise.

[00065] Upon actuation of the primary piston (302) along with the secondary piston (305), the hydraulic guiding means of the front master cylinder (300) aids in guiding the first protrusion (310) of the secondary piston (305) across the front master cylinder (300) and seal the secondary master cylinder bore (303) from leakage against hydraulic pressure build inside the front master cylinder (300). Further, because of the area difference between the primary master cylinder bore

(303) and the secondary master cylinder bore (304) a pressure is created across the front master cylinder (300) of a vehicle (100), which further aids in movement of the braking fluid towards the brake hose (212) through the banjo joint (202).

[00066] As per an embodiment, the first connection (309) is formed between the first protrusion (310) of the secondary piston (305) and said first coupling member (315) in the secondary master cylinder bore (303). The secondary piston (305) and the first coupling member (315) are held together by means of the lock pin (307). In another embodiment, the secondary master cylinder bore (303) is accessible for servicing purposes by dismantling the lock-pin and detaching the brake cable parts (308, and 306).

[00067] Thereby, the method of application of braking system of a vehicle ( 100) comprises of actuating a rear brake lever (not shown) in a direction towards a rider; relaying of actuated force from the rear brake lever to the first coupling member (315) connected to the first protrusion (310) of the secondary piston (305) housed in the secondary master cylinder bore (303) or secondary space (303), through a rear brake cable (308) attached to the first coupling member (315) connected to the first protrusion (310) of the secondary piston (305); pulling of a primary piston (302) housed in a primary master cylinder bore (304) or a primary space (304), inwardly in a direction operably away from a front brake control lever (208) by means of the secondary piston (305) that includes the first protrusion (310), while creating a working clearance between the primary piston (302) and the front brake actuation lever (208); thereby creating a pressure difference between the primary master cylinder bore (304) and the secondary master cylinder bore (303); transmitting of brake fluid through a banjo joint (202) and a hose (212) from the primary master cylinder bore (304) to front wheel disc brake (not shown); and braking of a front wheel (108) of a vehicle (100) by means of the front wheel disc (not shown).

[00068] Therefore, the present illustration illustrates a compound master cylinder (300) for a disc brake system of a vehicle comprising, a primary piston (302); and a secondary piston (305). A rear brake cable (308) is directly attached to a first coupling member (315). The first coupling member (315) is operably connected to the secondary piston (305), and the rear brake cable (308) pulls the first coupling member (315) along with the secondary piston (305) and actuates the braking system of said vehicle (100) by an inwardly movement in a direction operatively away from the front brake actuation lever (208) of the braking system of the vehicle (100).

[00069] Figure 4a to Figure 4c illustrates a sectional view of a front master cylinder (300) of a vehicle (100) during operation of only front braking (300) by means of a front brake actuation lever (208), in accordance with an embodiment of the present claimed subject matter. During front braking operation, when the rider applies only front brakes by pulling the front brake actuation lever (208) as shown in Figure 4c, then like standard functioning of the front brake actuation lever (208) as described in Fig.2, the front brake actuation lever (208) pushes the primary piston (302) which creates a pressure difference between the primary master cylinder bore (304) and the secondary master cylinder bore (303). The created pressure difference further pushes the secondary piston (305), which further aids in movement of the lubrication fluid through the brake hose (212) and the banjo joint (202).

[00070] However, during the application of only front brake actuation lever (208), the functioning of the synchronized braking or combined braking is not affected because of the clearance D3 (shown in Figure 4b) provided between at least an innermost part of the secondary master cylinder bore (303) and the first coupling member (315), which is further connected to at least one end of the first protrusion (310) of the secondary piston (305), by means of a first connection (309) of the front brake master cylinder (300).

[00071] Figure 5a to Figure 5c illustrates a sectional view of a front master cylinder (300) of a vehicle (100) during operation of only rear braking (300) by means of a rear brake control lever (not shown), in accordance with an embodiment of the present claimed subject matter. Unlike the known arts, where during synchronous braking or compound braking or combined braking is done; the piston (305) is actuated by the front brake actuation lever (208) and the additional lever or knocker (not shown). In the present subject matter, the piston (herein a primary piston (302) and a secondary piston (305)) is pulled from inside by means of the direct connection, herein called as a first connection (309), of the cable (308) within the first protrusion (310) by means of lock pin (307). Thereby, during the synchronous braking or combine braking, in the present subject matter, the front brake actuation lever (208) is not disturbed, keeping the front brake actuation lever (208) function, independent from the synchronous braking or combine braking.

[00072] The first connection (309) is shown by dotted line in Fig. 3b. During non-operable condition, a clearance of D3 is provided between at least an innermost part of the secondary master cylinder bore (303) and the first coupling member (315), which is further connected to at least one end of the first protrusion (310) of the secondary piston (305), by means of a first connection (309) of the front brake master cylinder (300). In the present illustration (Fig. 3b), the length of the primary piston (302) is shown as Dl, the length of the secondary piston (305) is shown as D2.

[00073] Moreover, a first joint (211) aids in holding the front brake actuation lever (208) in position, even during creation of a clearance because of the inside movement of the primary piston (302). Therefore, the first joint (211) holds the front brake actuation lever (208) in position, ensuring avoidance of any rattling noise. As per an embodiment, the first joint (211) includes a spring-loaded joint which helps to retain actuation lever (208) in extended condition thereby eliminating rattling noise.

[00074] Upon actuation of the primary piston (302) along with the secondary piston (305), the hydraulic guiding means of the front master cylinder (300) aids in guiding the secondary piston (305) across the front master cylinder (300) and seal the secondary master cylinder bore (303) via tertiary seal (301) from leakage against hydraulic pressure build inside the front master cylinder (300). Further, because of the area difference between the primary master cylinder bore (303) and the secondary master cylinder bore (304) a pressure is created across the front master cylinder (300) of a vehicle (100), which further aids in movement of the braking fluid towards the brake hose (212) through the banjo bolt (202).

[00075] As per an embodiment, the first connection (309) is formed between the first protrusion (310) of the secondary piston (305) placed inside the secondary master cylinder bore (303) and a first coupling member (315) in the secondary master cylinder bore (303). The secondary piston (305) and the first coupling member (315) are held together by means of the lock pin (307).

[00076] Figure 6a to Figure 6c illustrates a sectional view of a front master cylinder (300) of a vehicle (100) during operation of both front braking by front brake lever (208) and rear braking by means of a rear brake control lever (not shown), in accordance with an embodiment of the present claimed subject matter. Because of the simultaneous actuation of both the front brake actuation lever (208) and the rear brake control lever (not shown), the primary piston (302) is pulled from inside by means of the direct connection, herein called as a first connection (309), through force exerted by cable 308 inside the cable sheath (306) by means of the lock pin (307), and at the same time the front brake actuation lever (208) moves in the direction of the primary piston (302). However, because of the clearance created in between the primary piston (302) and the front brake actuation lever (208), the front brake actuation lever (208) is able to apply reduced pressure on the primary piston (302), ensuring avoidance of any hard braking experience during the operation. Thereby, during the synchronous braking or combine braking, along with the front braking, rider safety is additionally ensured due to avoidance of any hard braking.

[00077] Figure 7a to Figure 7b illustrates a schematic sectional view of a secondary master cylinder bore (303) of a front master cylinder (300) of a vehicle (100), in accordance with an embodiment of the present claimed subject matter. Figure 7a shows a side sectional view of the secondary master cylinder bore (303) during non-operable condition and the Figure 7b shows a side sectional view of the secondary master cylinder bore (303) during operable condition. [00078] A first connection (309) is formed between the first coupling member (315) and at least one end of the first protrusion (310) of the secondary piston (305) of the front brake master cylinder (300)first coupling member. The first connection (309) is established by means of a lock pin (307). As per an embodiment, at least one of the first protrusion (310) or the first coupling member (315) includes an elongated provision (313), to enable sliding movement of the lock pin (307) within the elongated provision (313).

[00079] Figure 8a to Figure 8c illustrates a sectional view of a secondary master cylinder bore (303) of a front master cylinder (300) of a vehicle (100), in accordance with an alternate embodiment of the present claimed subject matter.

[00080] Figure 8a shows a side sectional view of the secondary master cylinder bore (303) during non-operable condition. Figure 8b shows a side sectional view of the secondary master cylinder bore (303) during front brake actuation lever operation (208). Figure 8c shows a side sectional view of the secondary master cylinder bore (303) during rear brake control lever operation (not shown) during synchronized or combined braking.

[00081] A first connection (309) is formed between the first coupling member (315) and at least one end of the first protrusion (310) of the secondary piston (305) of the front brake master cylinder (300). first coupling member The first connection (309) is established by means of a collar pin (314).

[00082] As per an embodiment, in order to function, the secondary piston (305) is required to be concentric with the secondary master cylinder bore (303).

[00083] As per an alternate embodiment, in order to function, the primary master cylinder bore (304) is required to be concentric with the secondary master cylinder bore (303).

[00084] As per an aspect, the present subject matter is applicable to all three wheelers and two wheelers having a front disc brake system.

[00085] As per an aspect, the present subject matter is applicable to all three wheelers or two wheelers having a front disc brake and rear drum brake system. [00086] As per an aspect, the present subject matter is applicable to all three wheelers or two wheelers having a front disc brake and rear drum brake system including combined braking with a foot operated system.

[00087] As per an aspect, the present subject matter is applicable to all three wheelers or two wheelers having a front disc brake and rear drum brake including a combined braking or antilock braking system configuration with hand operated system or foot operated system.

[00088] Many modifications and variations of the present subject matter are possible in the light of above disclosure. Therefore, within the scope of claims of the present subject matter, the present disclosure may be practiced other than as specifically described.

LIST OF REFERENCE NUMERALS

100: Vehicle 25 126: Utility unit 102: Frame assembly 127: Seat unit 106: Power transmission assembly 128: Hinge unit 107: Rear wheel 129: Storage area utility assembly 108: Front wheel 130: Side panel LH

109: Handle bar assembly 30 131: Front cover 110: Left handle bar grip 132: Rear cover 111: Grab rail 133: Rear panel

112: Front suspension assembly 134: Handle bar rear panel 116: Front panel 200: Standard Front master cylinder 35 assembly 117: Tail lamp

201: Brake fluid reservoir 118: Glove box

202: Banjo joint 119: Front fender

203 : Master cylinder return spring 120: Rear fender 204: Master cylinder bore 121: Handle bar front panel 40 205 : Primary piston seal 122: Head light 206: Secondary piston seal 123: Mirror unit

207: Piston 124: Floor board 125: Bottom panel 208: Actuation lever or Front brake 306: Sheath307: Lock pin actuation lever

308: Cable

209a: Primary Orifice

20 309: First connection

209b: Secondary Orifice

310: First protrusion

210: Master cylinder housing

313: Elongated provision 211: First joint

314: Collar pin

212: Brake hose

315: First coupling member

300: Front master cylinder assembly

25 300: Front master cylinder assembly

301: Tertiary piston seal 302: Primary piston 303: Secondary space 304: Primary space

305: Secondary piston

Claims

I/We Claim:

1. A compound braking system of a vehicle (100) configured with: a front master cylinder assembly (300) for a disc brake wherein said front master cylinder assembly (300) comprises of a primary piston (302); and a secondary piston (305); and a front brake actuation lever (208) to actuate the front braking wherein, a rear brake cable (308) being directly attached to a first coupling member (315); wherein, said first coupling member (315) being operably connected to said secondary piston (305), and wherein, said rear brake cable (308) pulls said first coupling member (315) along with said secondary piston (305) and actuates said braking system of said vehicle (100) by an inwardly movement in a direction operatively away from said front brake actuation lever (208) of said braking system of said vehicle (100).

2. A method of application of front brake via actuation of a rear brake force for a compound combined braking system of a vehicle (100) comprising a front disc brake, a rear drum brake assembly (not shown): wherein said method consists of actuating a rear brake lever in a direction towards a rider; relaying of actuated force from said rear brake lever to a first coupling member (315) operably connected to a first protrusion (310) of a secondary piston (305) housed in a secondary space (303) of a front master cylinder assembly (300), through a rear brake cable (308) attached to said secondary piston (305); pulling of a primary piston (302) housed in a primary master cylinder bore (304), inwardly in a direction operatively away from a front brake actuation lever (208) by means of said secondary piston (305), thereby creating a working clearance between said primary piston (302) and said front brake actuation lever (208); creating a pressure difference between said primary master space (304) and said secondary space (303); transmitting of brake fluid through a banjo bolt joint (202) and a hose (212) from said primary master cylinder bore (304) to front wheel disc brake; and braking of a front wheel (108) of a vehicle (100) by means of said front wheel disc.

3. A compound master cylinder (300) for a disc brake system of a vehicle comprising: a primary piston (302); and a secondary piston (305); wherein, a rear brake cable (308) being directly attached to a first coupling member (315); wherein, said first coupling member (315) being operably connected to said secondary piston (305), and wherein, said rear brake cable (308) pulls said first coupling member (315) along with said secondary piston (305) and actuates said braking system of said vehicle (100) by an inwardly movement in a direction operatively away from said front brake actuation lever (208) of said braking system of said vehicle (100).

4. The braking system of a vehicle (100) as claimed in claim 2, wherein said primary space (304) and the secondary space (303) are configured with an area difference.

5. The braking system of a vehicle (100) as claimed in claim 1, wherein said secondary piston (305) protrudes as a first protrusion (310) in a secondary space (303), wherein said first protrusion (310) being configured with a first connection (309) between rear brake system and front brake system.

6. The braking system of a vehicle (100) as claimed in claim 1, wherein said actuation lever (208) is a front brake actuation lever (208).

7. The braking system of a vehicle (100) as claimed in claim 2, wherein said secondary space (303) includes a first coupling member (315).

8. The braking system of a vehicle (100) as claimed in claim 5, wherein said first compound connection (309) being formed between said first protrusion (310) of said secondary piston (305) and a first coupling member (315) by means of a locking or coupling means.

9. The braking system of a vehicle (100) as claimed in claim 8, wherein said locking or coupling means include a lock pin (307) and said first coupling member (315).

10. The braking system of a vehicle (100) as claimed in claim 8, wherein said first coupling member (315) includes an elongated provision (313).

11. The braking system of a vehicle (100) as claimed in claim 1, wherein said secondary piston (305) is concentric with a secondary space (303).

12. The braking system of a vehicle (100) as claimed in claim 1, wherein said primary space (304) is concentric with said secondary space (303).

13. The braking system of a vehicle (100) as claimed in claim 1, wherein said secondary space (303) is accessible for service by dismantling the coupling provision (309).

14. The braking system of a vehicle (100) as claimed in claim 1 wherein a clearance of D3 is provided in between at least an innermost part of the secondary master cylinder bore (303) and a first coupling member (315), which is further connected to at least one end of said first protrusion (310) of said secondary piston (305), by means of a first connection (309) of said front brake master cylinder (300).

15. The braking system of a vehicle (100) as claimed in claim 1, wherein a banjo bolt joint (202) is disposed on a lateral wall of said front master cylinder (300).

16. The braking system of a vehicle (100) as claimed in claim 1, wherein a first joint (211) holds said front brake actuation lever (208) in position,

17. The braking system of a vehicle (100) as claimed in claim 1, wherein said front brake master cylinder (300) of said vehicle (100) includes a brake fluid reservoir (201).

18. The braking system of a vehicle (100) as claimed in claim 1 wherein said primary piston (302) is connected on one end to a front brake actuation lever (208) and another end of said primary piston (302) is extended as said secondary piston (305).

19. The braking system of a vehicle (100) as claimed in claim 1, wherein said primary piston (302) is sealed on both ends by means of a primary seal (206) and a secondary seal (205).

20. The braking system of a vehicle (100) as claimed in claim 1, wherein a master cylinder return spring (203) is wounded over the secondary piston (305).

21. The braking system of a vehicle (100) as claimed in claim 20, wherein one end of said master cylinder return spring (203) abuts a secondary piston seal (205) disposed one end of a primary piston (302), wherein other end of said master cylinder return spring (203) abuts a tertiary piston seal (301) disposed on one end of a primary master cylinder bore (304) in the direction away from said primary piston (302).

22. The braking system of a vehicle (100) as claimed in claim 21, wherein at least one of a primary piston seal (205), said secondary piston seal (206), and said tertiary piston seal (301) is a cup seal type of seal.

23. The braking system of a vehicle (100) as claimed in claim 1, wherein, said secondary piston (305) is an extension of said primary piston (302), wherein said secondary piston (305) is integrated to said primary piston (302)