WO2005042325A1

WO2005042325A1 - Brake system

Info

Publication number: WO2005042325A1
Application number: PCT/KR2003/002314
Authority: WO
Inventors: Jae-Ok Lee
Original assignee: Jae-Ok Lee
Priority date: 2003-10-31
Filing date: 2003-10-31
Publication date: 2005-05-12
Also published as: AU2003274795A1

Abstract

This utility model relates to a brake system for sensing a sudden deceleration due to manipulation for sudden brake, and then rendering the brake to be operated with two-stage, thereby minimizing a distance of brake and enhancing a safety sense upon taking a car. Specifically, the utility model comprises a nose-down sensing means sensing nose-down due to a sudden brake upon manipulating a brake pedal, an oil pressure control device controlling a break pressure supplied from a master cylinder to each wheel, and a controller controlling the oil pressure control device to release the brake operation according to a nose-down signal to be inputted through the nose-down sensing means, and then operating again the brake after a center of weight shifts to rear wheels by restitution force of suspension device of front wheels, thereby rendering the brake to be operated with two-stage.

Description

TITLE BRAKE SYSTEM

TECHNICAL FIELD This invention relates to a brake system, and more particularly to a brake system for sensing a sudden deceleration due to a driver's manipulation for sudden brake, and then rendering the brake to be operated with two-stage, wherein the brake is primarily operated together with the driver's manipulation for brake pedal, the brake operation is released upon a nose-down due to the primary brake operation so that a center of weight for a car body is shifted to a rear part of the car body, and then the brake is secondarily operated to render the same braking force to be generated in front wheels and rear wheels, thereby minimizing a distance of brake.

BACKGROUND ART Generally, a transportation vehicle, such as an automobile, provided with an engine and traveling by transferring a power generated from the engine to wheels is provided with a brake system for deceleration of traveling speed or stop. The brake system comprises a brake pedal converting a pedaling force to a mechanical force, a master cylinder changing the mechanical force of the brake pedal to a oil pressure operating force, a brake oil pressure line transferring the oil pressure generated from the master cylinder to the respective wheel, a wheel cylinder converting the supplied oil pressure operating force to a mechanical force through the brake oil pressure line, and a braked device decelerating the revolution of wheel by the mechanical force of the wheel cylinder. Here, the b rake d evice includes a disc coupled with the wheel a nd a brake pad frictionally contacted to the disc, or a drum coupled with the wheel and a brake shoe frictionally contacted to the drum. According to the prior brake system constituted as described above, if a driver steps a brake pedal to decelerate a speed of car or to stop during driving a car, the brake pedal changes the driver's pedaling force to the mechanical force, a master cylinder generates an oil pressure operating force by the mechanical force generated form the brake pedal, the oil pressure operating force generated by the master cylinder is transferred to a wheel cylinder through a brake oil pressure line, and then the wheel cylinder receiving the oil pressure operating force through t he brake o il p ressure I ine actuates a brake d evice s o t hat t he wheel cylinder decelerates the revolution rate of the wheels to stop the car. According to the prior brake system, however, if a driver steps a brake pedal to decelerate a speed of car or to stop during driving a car, as a result of a relative motion of a wheel having a decelerating revolution speed and a car body having an inertial motion, there has been occurred a phenomenon that a center of weight for the car body is shifted to the front wheel side, and a load is concentraively applied to the car body of the front wheel side, thereby the front wheels going down, and the rear wheels going up. Thus, if the brake is operated in the status that the rear wheels are lifted, there has been a problem that a brake distance is longer since the braking force is generated only by the front wheels. Further, as described above, if the front wheel side goes down, and the rear wheel side goes up upon operating the brake, there has been a problem that passengers feel uneasy about that.

DISCLOSURE OF THE INVENTION Therefore, in order to resolve the above problems, an object of the invention is to provide a brake system for sensing a sudden deceleration due to a driver's manipulation for sudden brake, and then rendering the brake to be operated with two-stage, wherein the brake is primarily operated together with the driver's manipulation for brake pedal, the brake operation is released upon a nose-down due to the primary brake operation so that a center of weight for a car body is shifted to a rear part of the car body, and then the brake is secondarily operated to render the same braking force to be generated in front wheels and rear wheels, thereby minimizing a distance of brake.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawing, in which:

Fig. 1 is a main constitutional view for showing an embodiment according to the invention; Fig. 2 is a detailed constitutional view of an embodiment according to the invention; Fig. 3 is a block constitutional view for showing an embodiment of a controller according to the invention; Fig. 4 is a block constitutional view for showing the other embodiment of a controller according to the invention; Fig. 5 is a main constitutional view for showing the other embodiment according to the invention; Fig. 6 is a detailed constitutional view of the other embodiment according to the invention; and Fig. 7 is a view of braking process according to the invention.

BEST MODE FOR CARRYING OUT THE INVENTION According to a brake system of the invention, after a center of weight shifted to a front wheel side is dispersed and shifted to a rear wheel side according to a deceleration generated by a driver's manipulation for a brake, the brake is again operated, thereby a distance of brake being minimized. The brake system comprises a nose-down sensing means sensing nose-down due to a sudden brake upon manipulating a brake pedal 140; an oil pressure control device controlling a oil pressure supplied from a master cylinder 110 to each wheel; and a controller 210 controlling the oil pressure control device to release the brake operation according to a nose-down signal to be inputted through the nose-down sensing means, and then operating again the brake after a center of weight shifts to rear wheels by restitution force of suspension device of front wheels, thereby rendering the brake to be operated with two-stage. Here, the nose down sensing means is fixed to a chassis of the front wheels side, and the means has a shock-absorber sensing sensor 260 for sensing up and down freely moving amount of the shock absorber 130. When the nose-down occurs due to a sudden brake, the nose down sensing means senses the nose-down due to a sudden deceleration through the shock-absorber sensing sensor 260, and then generates a nose-down signal. If the nose-down is restored, the nose down sensing means senses such a status, and then outputs a restoration signal. As a result, the controller 210 makes a secondary brake operation. Further, a nose-down sensing means according to the other embodiment of the invention includes a pedal sensor sensing the brake manipulation, a car speed sensing sensor 240 sensing the speed of car, and a car speed comparison output section 220 comparing and determining a deceleration ratio of the car speed sensing sensor into which a signal from the pedal sensing sensor 230 is inputted, and outputting the nose-down signal by determining a sudden deceleration when the speed of car is rapidly reduced by 10 to 30Km/h per second. When the driver manipulates the brake, the car speed comparison output section 220 receives the brake manipulation signal of the driver from the pedal-sensing sensor 230. Then, the car speed comparison output section 220 receives a speed of car through the car speed-sensing sensor 240 after the brake manipulation signal is inputted. If the car speed comparison output section 220 determines a sudden deceleration when the speed of car is rapidly reduced by 10 to 30Km/h per second, it outputs the nose down signal. Then, the controller 210 controls the oil pressure control device by the inputted signal, thereby rendering the brake operation to be released. After a predetermined time (0.1 to 0.5 second), the car speed comparison output section 220 outputs a restoration signal, and then the controller 210 controls the oil pressure control device, thereby operating again the brake. Meanwhile, the oil pressure control device comprises an oil pressure control section controlling an oil flow from the master cylinder 110 to a wheel cylinder 120, and an oil pressure generating section operating the brake by supplying an oil pressure having a predetermined pressure u pon the second brake operation after releasing the brake due to the nose-down. Here, the oil pressure control section 400 includes a valve body 410 formed with oil pressure tubing and a valve room for controlling oil pressure flow to render oil pressure from the master cylinder 110 and the oil pressure generating section to serve as a wheel cylinder, a valve load 420 rendering the wheel cylinder to be opened to any one in the master cylinder 110 or the oil pressure generating section according to the frequent motion by coupling with the valve room to be elastically projected via an elastic means such as a spring, and a valve solenoid 430 for rendering the valve load to make a frequent motion according to the control of the controller 210. Further, the oil pressure generating section includes a master shut-off valve 316 installed within the master cylinder 110 and the oil pressure control section 400 to release the oil pressure operated into the wheel cylinder 120 upon the nose-down, the master shut-off valve closing the passage from the master cylinder 110 to the oil pressure control section 400, and opening the passage from the master cylinder 110 to an auxiliary oil tank 312 when the nose-down signal is inputted according to the control of the controller 210, an oil pressure pump 400 pumping an oil from the auxiliary oil tank 312 according to the control of the controller 210 to maintain a constant oil pressure within a pressurization tank 313 connected to the oil pressure control section 400, an oil pressure sensor 315 for controlling the operation of the oil pressure pump 311 by sensing the oil pressure of the pressurized tank 313 through the oil pressure pump 311 , and a bypass valve 314 bypassing the oil the sucking passage of the oil pressure pump 311 when the oil pressure applied to the pressurization tank 313 is more than a predetermined oil pressure. When a transportation vehicle is moved, an oil pressure within the pressurization tank 313 by the oil pressure pump 311 controlled by the controller 210 is maintained with a constant oil pressure. When the oil pressure is maintained as described above, If the nose down signal is inputted to the controller 210, the controller 210 controls the master shut-off valve 316, thereby closing a flow from the master cylinder 110 to the oil pressure control section 400. The oil pressure operated into the wheel cylinder 120 is released into the auxiliary oil tank 312, thereby releasing the operation of the brake. Then, if, after a predetermined time, a secondary brake operation signal is inputted to the controller 210, the controller 210 controls the oil pressure control section 400. As a result, a passage from the pressurization tank 313 to the wheel cylinder 120 is opened, thereby the secondary brake being operated by the oil pressure of the pressurization tank 313. Further, the oil pressure generating section according to the other embodiment of the invention includes an auxiliary cylinder 321 connected to the oil pressure control section 400, and a cylinder driving section 322 driving the auxiliary cylinder 321 according to the control of the controller 210. The cylinder driving section 322 includes a moveable control motor controlled by the controller 210, and a driving cam 323 rotated by the moveable control motor for operating a cylinder of the auxiliary cylinder. In the process of operation of the transportation vehicle, if the nose down signal is inputted to the controller 210, the controller 210 controls the oil pressure control section 400, thereby closing a passage from the master cylinder 110 to the wheel cylinder 120, and opening a passage from the master cylinder 110 to the auxiliary cylinder 120. Then, the oil pressure operated into the wheel cylinder 120 is released into the auxiliary oil tank 312. If, after a predetermined time, a secondary brake operation signal is inputted to the controller 210, the controller 210 controls the cylinder driving section 322. As a result, the oil pressure generated by the auxiliary cylinder 321 is supplied to the wheel cylinder 120, thereby operating the secondary brake. Meanwhile, the brake system further may comprises a wheel sensor 250 for sensing a rolling rate of the wheel to prevent a slippage resulted from exceeding the yield friction limit between the wheel and the ground surface due to a deviation between the rolling rate of the wheel and the speed of the car when a secondary brake is operated by the control of the controller 210, and for rendering the controller 210 to control the oil pressure supply from the oil pressure generation section to the wheel cylinder 120 in order to render the deviation between the rolling rate of the wheel and the speed of the car to make a brake within the yield friction limit between the wheel and the ground surface. The wheel sensor 250 may be provided to the respective wheel. The wheel sensor independently has the oil pressure section 400 supplying the wheel cylinder with the oil pressure from the oil pressure generating section between the wheel cylinder 120 of a left front wheel and the wheel cylinder of a right front wheel, and also between the rear wheels. As a result, when the secondary brake is operated, the slippage of the wheels is prevented, thereby the brake being made with the wheel and the ground surface maintaining the maximum friction force. As described above, the brake system according to the invention comprises a nose-down sensing means sensing nose-down due to a sudden brake upon manipulating a brake pedal 140; an oil pressure control device controlling a oil pressure supplied from a master cylinder 110 to each wheel; and a controller 210 controlling the oil pressure control device to release the brake operation according to a nose-down signal to be inputted through the nose-down sensing means, and then operating again the brake after a center of weight shifts to rear wheels by restitution force of suspension device of front wheels, thereby rendering the brake to be operated with two-stage. Upon operating the transportation vehicle, such as a car, if the nose down sensing means outputs the nose down signal due to a sudden brake manipulation, the controller 210 receiving the nose down signal shuts off a flow of oil pressure from the master cylinder to the wheel cylinder 120, and releases the oil pressure operated to the wheel cylinder 120, thereby releasing the brake operation. As described above, if the brake operation is released, the car body with nose-down is lifted by restitution force of a suspension device, and then a center of weight is shitted to the rear side of the car body by inertia. At this time, if the controller 210 operates an oil pressure for the secondary brake operation by controlling the oil pressure generating section, an inertial flow due to a deceleration is generated. However, since the inertial flow due to a deceleration is almost lost, a load of the car body is uniformly dispersed to the front wheel and the rear wheel, thereby the braking force being uniformly made. As a result, a distance of brake is reduced, and passengers feel a safety sense even upon a sudden brake by keeping the car body horizontally. Meanwhile, in case that the respective wheel is provided with the wheel sensor 250 like the other embodiment of the invention, if the slippage for losing the friction force between the wheel and the ground surface is about to be generated since the deviation between a rolling speed of the wheel and a speed of car is largely generated upon a secondary brake operation, a secondary oil pressure operated to the wheel cylinder is released. Then, if a rolling speed of the wheel is restored, a secondary oil pressure is again operated to the wheel cylinder, thereby the brake being made with maintaining the maximum friction force between the wheel and the ground surface until the car is stopped.

INDUSTRIAL APPLICABILITY From the foregoing, a brake system according to the invention renders the brake to be operated with two-stage by supplying a wheel cylinder with an oil pressure generated from an oil pressure generating section controlled by a controller, thereby a load concentrated upon a front wheel upon the brake operation being dispersed to a rear wheel, and a distance of brake being innovatively minimized. Further, since a braking force is uniformly generated in the front and rear wheels by evenly dispersing a load of car body to the front and rear wheels, the car body is entirely settled down, thereby passengers feeling a safety sense.

Claims

1. A brake system comprising: a nose-down sensing means sensing nose-down due to a sudden brake upon manipulating a brake pedal 140; an oil pressure control device controlling a oil pressure supplied from a master cylinder 110 to each wheel; and a controller 210 controlling the oil pressure control device to release the brake operation according to a nose-down signal to be inputted through the nose-down sensing means, and then operating again the brake after a center of weight s hifts to rear wheels by restitution force of s uspension d evice of front wheels, thereby rendering the brake to be operated with two-stage, wherein the oil pressure control device includes an oil pressure control section controlling an oil flow from the master cylinder 110 to a wheel cylinder 120, and an oil pressure generating section operating the brake by supplying an oil pressure having a predetermined pressure upon the second brake operation after releasing the brake due to the nose-down.

2. The brake system according to claim 1 , wherein the nose down sensing means is fixed to a chassis of the front wheels side, the means having a shock-absorber sensing sensor 260 for sensing up and down freely moving amount of the shock-absorber 130.

3. The brake system according to claim 1 , wherein the nose-down sensing means includes a pedal sensor sensing the brake manipulation, a car speed sensing sensor 240 sensing the speed of car, and a car speed comparison output section 220 comparing and determining a deceleration ratio of the car speed sensing sensor into which a signal from the pedal sensing sensor 230 is inputted, and outputting the nose-down signal by determining a sudden deceleration when the speed of car is rapidly reduced by 10 to 30Km/h per second.

4. The brake system according to claim 1 , wherein the oil pressure control section 400 includes a valve body 410 formed with oil pressure tubing and a valve room for controlling oil pressure flow to render oil pressure from the master cylinder 110 and the oil pressure generating section to serve as a wheel cylinder, a valve load 420 rendering the wheel cylinder to be opened to any one in the master cylinder 110 or the oil pressure generating section according to the frequent motion by coupling with the valve room to be elastically projected via an elastic means such as a spring, and a valve solenoid 430 for rendering the valve load to make a frequent motion according to the control of the controller 210, wherein the oil pressure generating section includes a master shut-off valve 316 installed within the master cylinder 110 and the oil pressure control section 400 to release the oil pressure operated into the wheel cylinder 120 upon the nose-down, the master shut-off valve closing the passage from the master cylinder 110 to the oil pressure control section 400, and opening the passage from the master cylinder 110 to an auxiliary oil tank 312 when the nose-down signal is inputted according to the control of the controller 210, an oil pressure pump 400 pumping an oil from the auxiliary oil tank 312 according to the control of the controller 210 to maintain a constant oil pressure within a pressurization tank 313 connected to the oil pressure control section 400, an oil pressure sensor 315 for controlling the operation of the oil pressure pump 311 by sensing the oil pressure of the pressurized tank 313 through the oil pressure pump 311 , and a bypass valve 314 bypassing the oil the sucking passage of the oil pressure pump 311 when the oil pressure applied to the pressurization tank 313 is more than a predetermined oil pressure.

5. The brake system according to claim 1 , wherein the oil pressure control section 400 includes a valve body 410 formed with oil pressure tubing and a valve room for controlling oil pressure flow to render oil pressure from the master cylinder 110 and the oil pressure generating section to serve as a wheel cylinder, a valve load 420 rendering the wheel cylinder to be opened to any one in the master cylinder 110 or the oil pressure generating section according to the frequent motion by coupling with the valve room to be elastically projected via an elastic means such as a spring, and a valve solenoid 430 for rendering the valve load to make a frequent motion according to the control of the controller 210, wherein the oil pressure generating section includes an auxiliary cylinder 321 connected to t he o il p ressure control section 400, and a cylinder d riving section 322 driving the auxiliary cylinder 321 according to the control of the controller 210.

6. The brake system according to any one of claims 1 to 5, wherein the brake system further comprises a wheel sensor 250 for sensing a rolling rate of the wheel to prevent a slippage resulted from exceeding the yield friction limit between the wheel and the ground surface due to a deviation between the rolling rate of the wheel and the speed of the car when a secondary brake is operated by the control of the controller 210, and for rendering the controller 210 to control the oil p ressure s upply f rom t he o il p ressure g eneration s ection t o t he w heel cylinder 120 in order to render the deviation between the rolling rate of the wheel and the speed of the car to make a brake within the yield friction limit between the wheel and the ground surface.

7. The brake system according to any one of claims 1 to 5, wherein the brake system further comprises a wheel sensor 250 for sensing a rolling rate of the wheel to prevent a slippage resulted from exceeding the yield friction limit between the wheel and the ground surface due to a deviation between the rolling rate of the wheel and the speed of the car when a secondary brake is operated by the control of the controller 210, and for rendering the controller 210 to control the oil p ressure s upply from the o il p ressure g eneration section to t he wheel cylinder 120 in order to render the deviation between the rolling rate of the wheel and the speed of the car to make a brake within the yield friction limit between the wheel and the ground surface, wherein the wheel sensor 250 is provided to the respective wheel, the wheel sensor independently having the oil pressure section 400 supplying the wheel cylinder with the oil pressure from the oil pressure generating section between the wheel cylinder 120 of a left front wheel and the wheel cylinder of a right front wheel, and also between the rear wheels.