Brake Control Apparatus

Field of the Invention:

This invention relates to brake control apparatus and more particularly for a motorcycle.

Background of be Invention:

Combined Brake systems are brake systems for two wheelers that operate both foundation brake systems (front and rear) through the actuation of only one lever (either rear or front or both). Combined brake system are generally passive systems that work on a fixed brake force distribution between the front and rear foundation brakes with a limiter to prevent wheel lock up.

If the wheel locks up, the rider is likely to lose control of the vehicle resulting in an accident. However different friction surfaces on the road and different loading conditions (solo/duals) demand different settings for the limiter to avoid wheel lock up.

Typically if the limiter is specifically set to avoid wheel lock up in worst situations like wet road, then it will be lead to non- optimal performance of the combined brake in other satiations.

Other known method for force distribution is use of active sensor systems to sense wheel lock up (similar to an antilock brake system) which increases the consumption of electrical energy, reduces fuel economy and increases cost significantly too.

Hence there is a need to develop a simple & cost effective solution that can change the settings of the limiter to prevent wheel lock up under various roads and load conditions.

Summary of the Invention:

An object of the present invention is to provide a brake control apparatus for combined brake system wherein the brake force distribution can be changed based on various road surface conditions like wet or dry roads.

Another object of the present invention is to provide a brake control apparatus for combined brake system wherein the brake force distribution is easy and quick.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Brief Description of the Drawings:

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein

Figure 1 shows a conventional motorcycle.

Figure 2 shows a brake control apparatus according to the present invention.

Detail Description of the Drawings:

The present invention now will be described more fully hereinafter with different embodiments. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather those embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the invention to those skilled in the art.

With reference to Figure 1 a motorcycle comprises of a frame (101), front fork (102) attached to a pivot tube (201) of the vehicle frame, a front wheel (103) attached to these front forks (102), a handle bar (104) connected to the front forks (102), a fuel tank (105) attached so as to straddle an upper part of the vehicle frame, a seat (106) attached to the upper rear portion of the vehicle frame, an engine unit (107) attached to the lower front section of the vehicle frame, a swing arm (108) attached to a lower rear section of the vehicle frame, suspended by a rear shock absorber (not shown) from the vehicle frame and a rear wheel attached to a rear end of swing arm (108). The intake system of the engine comprises of a fuel air metering device such as a carburetor (109), intake duct and an air cleaner. The exhaust system of the engine comprises of exhaust pipe and a mufflerv The motorcycle is also provided with a side cover for covering a side section of the vehicle frame, a seat cover for covering a rear section of the vehicle frame below the seat, a front fender (110) for covering an upper part of the front wheel (103), and a rear fender (111) for covering an upper part of the rear wheel (112). The drive from the engine (107) is transmitted from the engine to the driven wheel sprocket mounted on the rear wheel hub mounted on the rear wheel assembly.

According to the present invention and referring to Figure 2, a brake control apparatus in combined brake system for motorcycle comprises: a front master cylinder 201 hydraulically connected to the front brake calliper 202; a rear master cylinder 203 hydraulically connected to front 202 and rear brake calliper 204; a pressure control unit 205 hydraulically connected to front 201 and rear master cylinder 203; and a variable brake bias limiter 206 provided in the pressure control unit 205; wherein the variable brake bias limiter 206 is manually varied for different road surface conditions. The variable brake bias limiter 206 can be operated by solenoid 207 through an electrical switch 208.

The said pressure control unit 205 comprises: a control valve 209; a first passage 210 arranged between a front master cylinder 201 supplying brake fluid to a front brake calliper 202; a second passage 211 arranged between a rear master cylinder 203 supplying brake fluid to a rear brake calliper 204; wherein the control valve 209 moves due to the pressure difference created across the second passage 211 thereby pushing some brake fluid to front brake calliper 202; and wherein the variable brake bias limiter 206 arrest the movement of the control valve 209 to limit bias.

When front brake is applied oil flows in through opening 2 and flows through the passage 11 to the passage 10 and then through passage 4 to the front brake calliper applying the front brake.

When rear brake is applied oil flows through passage 1 to passage 9. This results in two actions:

- It allows some of the oil through passage 3 to the rear brake calliper 204 applying the rear brake.

- Due to difference in area on the left and right side in passage 9 the control valve 5 is forced to move to the left there by forcing the oil in passage 10 to move through passage 4 to the front brake calliper 202 applying the front brake too.

Thus the application of front brake will engage the front brake calliper 202 only but application of the rear brake will engage both the front and rear brake thus achieving a combined braking (CBS).

A hole is drilled on the screw 13 on the left hand side of pressure control valve housing 12. A threading operation is then carried out on this hole. Through this hole a variable brake bias limiter (hereinafter referred to as a stopper) 206 is screwed in and locked using a lock nut 15. The said stopper 206 will limit the movement of the control valve 209 to the left side thus preventing further operation of the CBS. The depth at which the stopper 15 is locked determines at what force the CBS stops functioning. Thus, the stopper 15 can be suitable positioned for different road and load conditions giving rise to different conditions of operation for the CBS

The said locking of the stopper 15 can also be done through an electric motor or solenoid 207 or pneumatic pump or similar mechanism to provide a power assisted adjustment to shift the CBS from one condition of operation to another.

Further this adjustment can also be automated using electronic controllers and sensors that judge the load and road surface conditions to shift from one condition of operation to another.

The first passage 210 according to the figure 2 include passage 2 and 11. The second passage 211 according to the figure include passage 1, 9 and 3.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims.

We Claim:

1. A brake control apparatus in combined brake system for motorcycle comprises:

a front master cylinder hydraulically connected to the front brake calliper;

a rear master cylinder hydraulically connected to front anfi rear brake calliper;

a pressure control unit hydraulically connected to front and rear master cylinder; and

a variable brake bias limiter provided in the pressure control unit;

wherein the variable brake bias limiter is manually varied for different road surface conditions.

2. The brake control apparatus as claimed in claim 1, wherein the variable brake bias limiter can be operated by solenoid through an electrical switch.

3. The brake control apparatus as claimed in claim 1, wherein the said pressure control unit comprises:

a control valve;

a first passage arranged between a front master cylinder supplying brake fluid to a front brake calliper;

a second passage arranged between a rear master cylinder supplying brake fluid to a rear brake calliper;

wherein the control valve moves due to the pressure difference created across the second passage thereby pushing some brake fluid to front brake calliper; and

wherein the variable brake bias limiter arrest the movement of the control valve to limit bias.

4. A brake control apparatus as substantially shown and described in the specification.