Description:TECHNICAL FIELD
[001] The present invention relates generally to brake pedals, and more specifically, to a variable ratio brake pedal assembly suitable for any vehicle.
BACKGROUND
[002] Vehicles, and in particular automotive vehicles, include a brake system for controlling the movement of the vehicle. Conventional brake systems include a brake pedal for transmitting a braking force from a vehicle operator to the wheels of the vehicle. The brake pedal is operatively coupled to a brake booster via a push rod. The brake booster is operatively connected to a master cylinder, and the master cylinder is operatively connected to a braking mechanism via brake lines. The braking mechanism is coupled to the wheel of the vehicle and applies the force to the wheel to slow down the rotational movement of the wheel. Various factors influence the overall efficiency of the brake system including the pedal lever ratio. In current design practice, pedal used in vehicles having fixed lever ratio.
[003] Pedal lever ratio refers to the geometric relationship between the levers that make up the brake pedal assembly. A typical brake pedal assembly includes a pedal arm, and an upper end of the pedal arm is pivotally mounted to a support bracket. The support bracket is fixedly mounted to the vehicle. A pedal pad is mounted to a lower end of the pedal arm for depression by the driver’s foot. The feel and effectiveness of the braking action experienced by the operator can be varied by changing the "pedal ratio". The "pedal ratio" is expressible as a ratio L1/L2, where "L1" is the distance between the pivot point for the pedal arm and the actuation point on the pedal pad, and "L2" is the distance between the pivot point and the booster rod attachment point. A high pedal ratio can be effective, but the long pedal travel results in a "spongy" feel to the brakes. Conversely, a low pedal ratio is the result of a shorter pedal travel, however, the shorter pedal travel results in an abrupt or sharp braking action.
[004] Therefore, there exists a need for a variable ratio brake pedal assembly suitable for any vehicle, which eliminates the aforementioned drawbacks.
OBJECTS
[005] The principal object of the embodiments disclosed herein is to provide a variable ratio brake pedal assembly suitable for any vehicle.
[006] Another object of the embodiments disclosed herein is to provide the variable ratio brake pedal assembly which provides variable pedal ratio with respect to pedal travel, thereby resulting in a reduced input pedal pressure.
[007] Yet another object of the embodiments disclosed herein is to provide the variable ratio brake pedal assembly which provides high deceleration with lower/lesser pedal effort.
[008] Still another object of the embodiments disclosed herein is to provide the variable ratio brake pedal assembly which includes a unique cam profile configured to actuate a booster push rod/ booster fork in a linear direction to generate a pressure to operate a vehicle braking system.
[009] Another object of the embodiments disclosed herein is to provide the variable ratio brake pedal assembly which includes an additional guiding mechanism for facilitating a linear movement of the booster push rod and thereby restricting an angular movement of the booster fork.
[0010] Still another object of the embodiment disclosed herein is to provide the variable ratio brake pedal assembly which is adapted to increase a booster input pressure with respect to variable lever ratio, provide a good initial brake bite, and deceleration with low pedal travel.
[0011] Still another object of the embodiment disclosed herein is to provide the variable ratio brake pedal assembly which is simple, easy to manufacture.
[0012] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF DRAWINGS
[0013] The embodiments herein are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0014] FIG. 1 depicts a front view of a conventional brake pedal assembly with a fixed lever ratio;
[0015] FIG. 2 is a perspective view of an embodiment of a variable ratio brake pedal assembly in accordance with the present invention;
[0016] FIG. 3a is an exploded view of an embodiment of the variable ratio brake pedal assembly in accordance with the present invention;
[0017] FIG. 3b is another exploded view of an embodiment of the variable ratio brake pedal assembly in accordance with the present invention;
[0018] FIG. 4 is a side view of an embodiment of the variable ratio brake pedal assembly in accordance with the present invention;
[0019] FIG. 5 is a top view of an embodiment of the variable ratio brake pedal assembly in accordance with the present invention;
[0020] FIG. 6 is another side view of the variable ratio brake pedal assembly depicting a direction of booster fork travel and a direction of rotation of a cam of the variable ratio brake pedal assembly, in accordance with the present invention; and
[0021] FIG. 7 depicts a closer perspective view of the cam engaging with a roller of the variable ratio brake pedal assembly, in accordance with the present invention.
DETAILED DESCRIPTION
[0022] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0023] The embodiments herein achieve a variable ratio brake pedal assembly suitable for any vehicle. Further, the embodiments herein achieve the variable ratio brake pedal assembly which provides variable pedal ratio with respect to pedal travel, thereby resulting in a reduced input pedal pressure. Furthermore, the embodiments herein achieve the variable ratio brake pedal assembly which provides high deceleration with lower/lesser pedal effort. Additionally, the embodiments herein achieve the variable ratio brake pedal assembly which includes a unique cam profile configured to actuate a booster push rod/ booster fork in a linear direction to generate a pressure to operate a vehicle braking system. Moreover, the embodiments herein achieve the variable ratio brake pedal assembly which is simple, easy to manufacture. Further, the embodiments herein achieve the variable ratio brake pedal assembly which includes an additional guiding mechanism for facilitating a linear movement of the booster push rod and thereby restricting an angular movement of the booster fork. Also, the embodiments herein achieve the variable ratio brake pedal assembly which is adapted to increase a booster input pressure with respect to variable lever ratio, provide a good initial brake bite, and deceleration with low pedal travel. Referring now to the drawings and more particularly to FIGS. 1 through FIG. 7, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0024] FIG. 1 depicts a front view of a conventional brake pedal assembly with a fixed lever ratio. Conventional brake systems include a brake pedal for transmitting a braking pressure from the vehicle operator to the wheels of the vehicle. The brake pedal is operatively coupled to a brake booster via a push rod. The brake booster is operatively connected to a master cylinder, and the master cylinder is operatively connected to a braking mechanism via brake lines. The braking mechanism is coupled to a wheel of the vehicle and applies the force to the wheel to slow down the rotational movement of the wheel. However, the conventional systems have a constant lever ratio which leads to lower initial brake bite, high pedal travel and booster input pressure increase linearly with input pedal pressure.
[0025] FIG. 2 is a perspective view of an embodiment of a variable ratio brake pedal assembly in accordance with the present invention. In an embodiment, the variable ratio brake pedal assembly (100) includes a brake booster input element (or booster push rod) (102) as shown in FIG. 2, a foot operated brake pedal lever (104) having a first end (104a) and a second end (104b), a foot pad (106), a brake booster (112) unlike any other brake pedal assembly. Further, the present invention (100) includes a cam (108), an input connector (110), a cam engaging surface (110s), at least two guide bracket (114), a pair of booster forks (116), a plunger (118), a roller (120), a pair of hollow guide bars (122), and a yoke (124).
[0026] FIG. 3a is an exploded view of an embodiment of the variable ratio brake pedal assembly in accordance with the present invention. FIG. 3b is another exploded view of an embodiment of the variable ratio brake pedal assembly in accordance with the present invention. The variable ratio brake pedal assembly (100) includes the brake pedal lever (104) which is fabricated to have the cam profile (108) towards the first end of the pedal lever (104). The brake pedal includes the foot pad (106) which is provided at the opposite (or second) end (104b) of the brake pedal lever (104). The foot pad (106) is operated by a user to apply pressure for actuating a braking system (not system). The foot pad (106) is operated by the user to move the brake pedal lever (104) from between a brake release position and a full brake position. In an embodiment, the cam (108) is constructed to apply an increasing variable pressure on the brake system of the vehicle, thereby providing a variable pedal ratio, when the brake pedal lever (104) is actuated from said brake release position to said full brake position. In another embodiment, the cam (108) is being constructed for translating an angular displacement of the pedal lever (104) to a linear displacement of the input connector (110). The cam (108) is adapted to rotate in a clockwise direction in a first arc shape, when the brake pedal lever (104) is actuated from the brake release position to the full brake position as shown in FIG. 6. Also, the cam (108) is adapted to rotate in anti-clockwise direction in a second arc shape, when the brake pedal lever (104) is released from the full brake position to the brake release position. In an embodiment, the cam (108) is a variable ratio cam having a profile such that the cam (108) has a tangential contact with the brake fork (116) during pedal actuation. The cam (108) of the pedal lever (104) defines an opening at a predetermined position towards the first end (104a) of the pedal lever (104), such that the opening receives a pin to pivotally secure the first end (104a) of the brake pedal lever (104) to a frame (not shown) of the vehicle.
[0027] FIG. 4 is a side view of an embodiment of the variable ratio brake pedal assembly in accordance with the present invention. FIG. 5 is a top view of an embodiment of the variable ratio brake pedal assembly in accordance with the present invention. The variable ratio brake pedal assembly (100) includes a guide mechanism (not shown) which is provided to support linear travel of the input connector (110) and thereby eliminating an angular moment of the input connector (110). In an embodiment, the guide mechanism includes the at least two guide bracket (114) which is engaged with said input connector (110). Each of the guide bracket (114) defines a slot S of predetermined shape. Further, the guide mechanism includes the pair of booster forks (116) disposed towards an inner side of the guide brackets (114). The booster forks (116) are provided in the assembly (100) so as to transmit the pressure of the brake pedal lever (104) to the brake booster (112). Furthermore, the guiding mechanism includes the pair of hollow guide bars (122) which are adapted to receive the corresponding pair of booster forks (116). The pair of hollow guide bars (122) are fabricated such that the pair of booster forks (116) slide inside the hollow guide bars (122). The pair of guide bars (122) are supported on a base towards said brake booster. The guiding mechanism further includes the plunger (118) which is provided transverse to the pair of booster forks (116). The plunger (118) is provided such that the plunger (118) slides within the slot S formed in the guide bracket (114).
[0028] FIG. 7 depicts a closer perspective view of the cam engaging with a roller of the variable ratio brake pedal assembly, in accordance with the present invention. The variable ratio brake pedal assembly (100) includes the input connector (110) connected between the brake booster input element (102) and said cam (108) of said pedal lever (104), said input connector (110) having a cam engaging surface (110s) and adapted to move axially to actuate a brake system. In an embodiment, the input connector (110) includes the roller (120) which is engaged to the cam (108). The roller (120) is designed such that the roller provides a surface contact which is a tangential contact to the cam (108). The angular movement of the brake pedal lever (104) is transmitted initially to the roller (120), whereby the roller (120) transmits the movement of the brake pedal lever (104) to a linear movement of the brake booster input element (or booster push rod) (102). Further, the input connector (110) includes the yoke (124) which connects the roller (120) and the booster input element (102). The yoke (124) further includes a first member (not shown) engaged to the roller (120) and a second member (not shown) engaged to the booster input element (102). The first member and the second member of the yoke are connected through a shaft (not shown) of predetermined diameter.
[0029] The technical advantages disclosed by the embodiments herein are reduced input pedal force, high deceleration with lower/lesser pedal effort, is simple, easy to manufacture, and linear movement of the booster push rod and thereby restricting an angular movement of the booster fork.
[0030] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
, Claims:We claim,
1. A variable ratio brake pedal assembly (100) in a vehicle to operate a brake booster input element (or booster push rod) (102), said brake pedal assembly (100) having a foot operated brake pedal lever (104), said pedal lever (104) having a first end (104a) pivotally supported to a frame for angular displacement and a second end (104b) having a foot pad (106), said brake pedal lever (104) operable between a brake release position and a full brake position, said assembly (100) comprising;
a cam (108) of predetermined shape defined at said first end (104a) of said pedal lever (104);
an input connector (110) connected between the brake booster input element (102) and said cam (108) of said pedal lever (104), said input connector (110) having a cam engaging surface (110s) and adapted to move axially to actuate a brake system;
a guiding mechanism disposed between said cam (108) and a brake booster (112) of said vehicle,
wherein,
said cam (108) is constructed to apply an increasing variable pressure on said brake system, thereby providing a variable pedal ratio, upon actuation of said brake pedal lever (104) from said brake release position to said full brake position; and
said guiding mechanism is provided to support linear travel of said input connector (110) and thereby eliminating an angular moment of the input connector (110).

2. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein said guiding mechanism includes:
at least two guide bracket (114) engaged to said input connector (110), each of said guide bracket (114) having a slot S of predetermined shape;
a pair of booster forks (116) disposed towards inner side of said guide brackets (114);
a pair of hollow guide bars (122) adapted to receive said corresponding pair of booster forks (116); and
a plunger (118) disposed transverse to each of said booster forks (116), said plunger (118) adapted to slide within said slot S of corresponding guide brackets (114).

3. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein said input connector (110) includes:
a roller (120) engaged to said cam (108), said roller having a surface contact with said cam (108); and
a yoke (124) connecting said roller (120) to said booster input element (102).

4. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein said cam (108) being constructed for translating an angular displacement of said pedal lever (104) to a linear displacement of said input connector (110), said cam (108) adapted to rotate clockwise in a first arc shape, when said brake pedal lever (104) is actuated from said brake release position to said full brake position, said cam (108) adapted to rotate anti-clockwise in a second arc shape, when said brake pedal lever (104) is released from said full brake position to said brake release position.

5. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein said pair of guide bars (122) are supported on a base towards said brake booster.

6. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein said cam (108) is a variable ratio cam having a profile such that said cam (108) has a tangential contact with said brake fork (116) during pedal actuation.

7. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein said cam (108) of said pedal lever (104) defines an opening at a predetermined position, such that said opening receives a pin to pivotally secure said first end (104a) of said brake pedal lever (104) to said frame of said vehicle.