DESC:Field of the invention
[0001] The present invention relates to a pneumatic braking system of an automobile. More particularly, the present invention relates to an actuator for an anti-lock braking system (ABS).

Background of the invention
[0002] Vehicles are equipped with brakes, which enables decelerating and stopping of the vehicle whenever require. Nowadays, the speed and weight of the vehicles are also increasing. Therefore, considering the safety of driving and transportation and to avoid accidents, Anti-lock braking system (ABS) is provided. The ABS prevents the vehicle from skidding at higher speed and on slippery surfaces. This helps in avoiding many accidents.

[0003] The number of components in the present ABS is high, which makes the present ABS bulky. Generally, each brake chamber or an actuator and brake chamber needs modulator valve with pipe and relevant connectors. Also, as the number of components is higher, the response time of the ABS is more. Specifically, the time required for stopping the vehicle from the instance of pressing the brake lever is higher, which causes delay in stopping the vehicle. Moreover, current ABS valve is having one inlet and one outlet also it is equipped with two coils one with a normally closed (NC) and other with a normally open (NO) type and the entire valve is compact and single unit, which decreases the response time while braking. This delay may lead to misjudging the stopping distance after applying brakes, which may lead to accidents.

[0004] Therefore, there is a need to provide an actuator for anti-lock braking system, which will overcome all the drawbacks of the existing anti-lock braking system.

Objects of the invention

[0005] Object of the present invention is to provide an actuator for Anti-lock braking system (ABS) of vehicles.

[0006] Another object of the present invention is to provide an actuator for anti-lock braking system, which can be used with the existing anti-lock braking system.

[0007] Yet another object of the present invention is to provide an actuator for anti-lock braking system, which does not require changes in existing program of an electronic control unit (ECU) for its working.

[0008] Still another object of the present invention is to provide an actuator for anti-lock braking system, which requires lesser number of components.

[0009] Further object of the present invention is to provide an actuator for anti-lock braking system, which is more responsive and has lesser time lag.

[0010] One more object of the present invention is to provide an actuator for anti-lock braking system, which is economical in construction.

[0011] Further one object of the present invention is to provide an actuator for anti-lock braking system, which is robust in construction.

[0012] Another objective of this invention is to provide an actuator for anti-lock braking system, which is enabled to work with existing ABS without changing working logic of ECU.

Summary

[0013] According to the present invention there is provided an actuator for antilock braking system of a vehicle. The actuator comprises at least one first valve and at least one second valve. The at least one first valve and the at least one second valve is arranged over a brake chamber. Specifically, the at least one first valve and the second valve is arranged over a first connecting chamber and a second connecting chamber respectively of the brake chamber. The at least one first valve regulates the flow of pressure signals towards the brake chamber from a foot brake valve. The at least one second valve regulates the pressure signal inside the brake chamber by selectively holding and releasing the pressure signal therefrom.

[0014] Further, the at least one first valve and the at least one second valve are solenoid operated diaphragm valve. Specifically, the at least one first valve and the at least one second valve are normally open solenoid valve and normally closed solenoid valves respectively. Electronic control unit operates the at least one first valve and the at least one second valve. Also, at least one sensor is arranged inside the brake chamber to provide signals to the Electronic Control Unit to operate the at least one first valve and the at least one second valve.

Brief Description of drawings
[0015] The advantages and features of the present invention will become better understood with reference to the following detailed description taken in conjunction with the accompanying drawings, wherein like elements are identified with like symbols, and in which:

[0016] Figure 1 shows a front cross sectional view of an actuator for anti-lock braking system, and

[0017] Figure 2 shows another front cross sectional view of the actuator for anti-lock braking system of figure 1.

Detail description of the invention
[0018] An embodiment of this invention, illustrating its features, will now be described in detail. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items.

[0019] The terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

[0020] The disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms.

[0021] The present invention provides an actuator for anti-lock braking system (ABS) of vehicles. The actuator can be used with the existing anti-lock braking system. Further, the actuator does not require changes to be made in program of an electronic control unit (ECU) for its working. Furthermore, the actuator requires lesser number of components and is more responsive with lesser time lag. Moreover, the actuator is economical and robust in construction.

[0022] Referring now to figures 1 and 2, an actuator 100 for an anti-lock braking system (ABS) in accordance with the present invention is illustrated. The actuator 100 is arranged over a brake chamber 200. The actuator 100 and the brake chamber 200 is arranged on a rigid frame (not shown in the figure) of a vehicle. Further, the brake chamber 200 is mounted on a chassis along with a bracket and is connected to a brake adjuster and a cam shaft as a conventional mounting methods. The actuator 100 may also be mounted to a disc brake of known type. A modulating facility of the actuator 100 is placed in vicinity of service side of the actuator 100 and the brake chamber 200 of the present invention. Modulation is done as per signals or inputs received by an Electronic Control Unit, hereafter referred as ECU. The present invention also serves purpose of normal brake chamber 200 or actuator 100 and brake chamber 200 if non ABS vehicle is using the actuator 100.

[0023] Specifically, the actuator 100 of the present invention includes at least one first valve and at least one second valve. In the present embodiment, one first valve 110 and one second valve 120 is provided. The first valve 110 and the second valve 120 is arranged over the brake chamber 200. The actuator 100 works on the logic of modular valve and ECU logic of the ABS.

[0024] The first valve 110 regulates the flow of pressure signals towards the brake chamber 200 from a foot brake valve 210. The second valve 120 regulates the pressure signal inside the brake chamber 200 by selectively holding and releasing the pressure signal therefrom. The pressure signals are the pressurized air received from a foot brake valve 210 upon applying braking force on a brake pedal (not shown in the figure). Further, the first valve 110 is arranged over a first connecting chamber 130 arranged on the brake chamber 200. Similarly, the second valve 120 is arranged over a second connecting chamber 140 arranged on the brake chamber 200.

[0025] Referring again to figures 1 and 2, the first connecting chamber 130 and the second connecting chamber 140 are interconnected and allow free passage of pressurized air there between. Further, the first valve 110 and the second valve 120 are solenoid valves. Specifically, the first valve 110 and the second valve 120 are solenoid operated diaphragm valves. Further, the first valve 110 is a normally open solenoid valve and the second valve 120 is a normally closed solenoid valve. Also, the first valve 110 and the second valve 120 are two-way solenoid valves. In an alternate embodiment, the second valve 120 is a pressure relief valve. It may be obvious to a person skilled in the art to configure the first valve 110 and the second valve 120 with any other valves performing similar functions. The first valve 110 and the second valve 120 with different sizes and shapes can be used in the present invention without affecting the working of the diaphragm 112 and 114 present inside the respective valves.

Specifically, the first valve 110 is a normally opened two-way solenoid valve and the second valve 120 is a normally closed two-way solenoid valve. Which means the diaphragm 112 inside the first valve 110 always allows the passage of air towards the brake chamber 200, when the first valve 110 is in “OFF” position. The diaphragm 114 inside the second valve 120 always hold the air inside the brake chamber 200 when the second valve 120 is in “OFF” position. Further, at least one sensor is arranged outside the brake chamber 200 and adjacent to the wheels. The sensor sends signal to the Electronic Control Unit to operate the first valve 110 and the second valve 120. The sensor may be selected from a wheel speed sensor, and accelerometers. It may be obvious to a person skilled in the art to select and use any other sensors to operate the Electronic Control Unit.
[0026] Further, the diaphragm 114 of the second valve 120 is connected to an opening (not shown in the figure). The ECU operates the second valve 120 for releasing the pressurized air to the atmosphere through the opening for lowering the pressure inside the brake chamber 200.

[0027] Function of the ABS is achieved by hold and release of the brakes to avoid skidding of the wheels on road using the actuator 100 of the present invention. Upon applying brakes, the pressurized air is passed through the foot brake valve 210 to the first valve 110. The diaphragm 112 inside the first valve 110 allows the pressurized air to pass to the brake chamber 200. During normal braking, the pressurized air applies pressure on brake pad and stops the rotation of vehicle wheels. When the rotation of the wheel is stopped, the pressurized air releases through the foot brake valve 210.

[0028] Further, the ECU continuously monitors the speed of the wheels using a wheel speed sensor (not shown). When the wheel speed sensor detects a condition indicative to wheel lock,, the wheel speed sensor sends signal to the ECU and the ECU operates the first valve 110 and the second valve 120 to control the pressure inside the brake chamber 200. In this condition, the ECU controls the first valve 110 by switching the first valve 110 to ON position. In the ON position, the diaphragm 112 inside the first valve 110 blocks the further passage of pressurized air from the foot brake valve 210. Now the pressurized air inside the brake chamber applies pressure to the brake pad. This condition is maintained for very short time. Thereafter, the second valve 120 is operated to the ON position by the ECU, to release the pressurized air from the brake chamber 200.

[0029] Again when the pressure decreases inside the brake chamber 200, the ECU operates the first valve 110 to the OFF position, thereby opening the diaphragm 112 and allowing the pressurized air to move inside the brake chamber 200. The diaphragm 112 inside the first valve 110 always allows the passage of air towards the brake chamber 200, when the first valve 110 is in “OFF” position. The pressurized air applies pressure on the brake pad to lower the speed of the wheel. Now the first valve 110 closes and opens the second valve 120 and releases the pressurized air to the atmosphere through the opening connected to the diaphragm 114 of the second valve 120. Again, pressurised air is allowed to flow through the foot brake valve 210. This cycle is continued to achieve ABS function until the brakes are released or if the wheels are not locking. Once the brakes are released, the pressurized air is exhausted through the foot brake valve 210.

[0030] .

[0031] Therefore, the present invention has an advantage of providing an actuator for anti-lock braking system (ABS) of vehicles. The actuator can be used with the existing anti-lock braking system. Further, the actuator does not require changes to be made in program of an electronic control unit (ECU) for working. Furthermore, the actuator requires lesser number of components and is more responsive with lesser time lag. Moreover, the actuator is economical and robust in construction.

[0032] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.
,CLAIMS:We Claim:
1. An actuator for antilock braking system of a vehicle, the actuator comprising:
At least one first valve arranged over a brake chamber for regulating the flow of pressure signals towards the brake chamber from a foot brake valve; and
At least one second valve arranged over the brake chamber for regulating the pressure signal inside the brake chamber by selectively holding and releasing the pressure signal therefrom.

2. An actuator as claimed in claim 1, wherein the at least one first valve is arranged over a first connecting chamber arranged on the brake chamber.

3. An actuator as claimed in claim 1, wherein the at least one second valve is arranged over a second connecting chamber arranged on the brake chamber.

4. The actuator as claimed in claim 1, wherein the at least one first valve and the second valve are solenoid valves.

5. The actuator as claimed in claim 1, wherein the at least one first valve and the at least one second valve are solenoid operated diaphragm valves.

6. The actuator as claimed in claim 1, wherein the at least one first valve is a normally open solenoid valve and the at least one second valve is a normally closed solenoid valve.

7. The actuator as claimed in claim 1, wherein the at least one first valve and the at least one second valve are operated by an electronic control unit.

8. The actuator as claimed in claim 1, further comprising at least one sensor for sending signal to the electronic control unit to operate the at least one first valve and the at least one second valve.

9. The actuator as claimed in claim 1, wherein the at least one second valve is a pressure relief valve.