KR20190033698A - Electric brake system and method thereof - Google Patents

Abstract

An electronic brake system is disclosed. A first embodiment of the present invention provides the electronic brake system, which comprises: a master cylinder discharging oil according to force of a brake pedal; a pedal displacement sensor sensing a displacement of the brake pedal; an oil pressure supply device generating oil pressure using rotational force of a motor operated by electric signals outputted by the pedal displacement sensor; an oil pressure control unit transferring the oil pressure, discharged by the oil pressure supply device, a wheel cylinder arranged at each wheel; a plurality of pressure sensors measuring the oil pressure within the oil pressure control unit; and an electronic control unit controlling the motor and valves based on information on the oil pressure and the displacement of the brake pedal, wherein the electronic control unit determines that the valves are out of order if an error between the measured oil pressure and preset estimated oil pressure is a preset first threshold or more. The present invention determines failures within an oil circuit to prevent brake malfunction.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electronic brake system,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electronic brake system, and more particularly, to an electronic brake system for detecting a hydraulic circuit failure and preventing a malfunction through valve control in a hydraulic circuit and a control method thereof.

The vehicle is essentially equipped with a brake system for braking. Recently, various types of systems have been proposed to obtain a more powerful and stable braking force.

Examples of the brake system include an anti-lock brake system (ABS) that prevents slippage of the wheel during braking, a brake traction control system (BTCS: Brake) that prevents slippage of the drive wheels And an electronic stability control system (ESC) that stably maintains the running state of the vehicle by controlling the brake hydraulic pressure by combining an anti-lock brake system and traction control.

Generally, an electronic brake system includes a hydraulic pressure supply device that receives an electric signal of a driver's braking will from a pedal displacement sensor that senses displacement of a brake pedal when the driver depresses the brake pedal, and supplies pressure to the wheel cylinder.

The hydraulic pressure supply device is configured to generate a braking pressure by operating the motor in accordance with the pressing force of the brake pedal. At this time, the braking pressure is generated by converting the rotational force of the motor into a linear motion and pressing the piston.

In particular, when the hydraulic pressure is generated by the motor, the position of the piston in the chamber mounted on the wheel is adjusted by the motor to adjust the liquid amount by using a constant relation between the braking pressure generated in the caliper and the amount of liquid flowing into the caliper, Pressure can be controlled.

In addition, when ABS, ESC, and TCS control is performed, the torque of the motor may be adjusted and the wheel valve may be controlled to obtain a quick control response.

However, the presence of a plurality of valves in the hydraulic circuit makes it necessary to quickly check the occurrence of problems such as the failure of braking pressure to be acquired by the electronic control unit during brake control.

To solve such a problem, an embodiment of the present invention attempts to determine a failure in a hydraulic circuit so as to prevent a braking malfunction.

In addition, when the failure is judged in the hydraulic circuit, the control is stopped to prevent the accident quickly.

According to an embodiment of the present invention, there is provided a brake pedal system comprising: a master cylinder for discharging oil according to a stroke of a brake pedal; a pedal displacement sensor for sensing a displacement of the brake pedal;

A hydraulic pressure supply device for generating a hydraulic pressure by using a rotational force of a motor operated by an electrical signal outputted from the pedal displacement sensor, and a hydraulic pressure control device for transmitting hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided in each wheel And an electronic control unit for controlling the motor and the valves based on the hydraulic pressure information and the displacement information of the brake pedal, the electronic braking system comprising: The electronic control unit may be provided with an electronic brake system for determining that the valve malfunctions if an error between the measured hydraulic pressure and a preset estimated hydraulic pressure is equal to or greater than a preset first threshold value.

In addition, the electronic control unit may previously store the estimated fluid pressure information according to the driving time of the motor, the opening / closing of the valve, and the driving time of the valve.

In the electronic control unit, when the pressure of the brake pedal is applied and the change amount of the hydraulic pressure in the hydraulic control unit is smaller than a second predetermined threshold value at the time of the operation of the motor, .

In addition, the hydraulic control unit may further include an outlet valve for controlling the hydraulic pressure of the wheel cylinder to be released, and the electronic control unit is operable, when the outlet valve is opened, It can be further judged by the failure of the valve.

According to another embodiment of the present invention, there is provided a brake pedal system including a master cylinder for discharging oil according to a pressure of a brake pedal, a pedal displacement sensor for sensing a displacement of the brake pedal, A hydraulic pressure control unit for transmitting the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided in each wheel, and a hydraulic pressure control unit for controlling the hydraulic pressure in the hydraulic pressure control unit, And an electronic control unit for controlling the motor and the valves based on the pressure information, the displacement information of the brake pedal, the electronic control unit, the electronic control unit, and the electronic control unit, Is judged to be a failure of the valve if the error of the valve is greater than or equal to a first threshold value There is a method of controlling the brake system of a child can be provided.

In addition, the predetermined estimated hydraulic pressure may be determined according to the drive time of the motor, whether the valve is open or closed, and the drive time of the valve.

Further, when the pressing force of the brake pedal is applied and the change amount of the hydraulic pressure in the hydraulic pressure control unit is smaller than a second predetermined threshold value at the time of operation of the motor, the valve can be further judged as a failure.

Further, if the outlet valve for controlling the fluid pressure of the wheel cylinder is opened and the hydraulic pressure of the wheel cylinder is not decreased, it can be further determined that the outlet valve is out of order.

The embodiment of the present invention is intended to solve such a problem, and it is possible to determine a failure in the hydraulic circuit so as to prevent a braking malfunction in advance.

In addition, when the failure is judged in the hydraulic circuit, the control is stopped so that the accident can be prevented promptly.

1 is a hydraulic circuit diagram showing a non-synchronized state of an electronic braking system of a vehicle according to an embodiment of the present invention.
2 is a hydraulic circuit diagram for explaining the flow of hydraulic pressure during normal braking of an electronic brake system of a vehicle according to an embodiment of the present invention.
3 is a hydraulic circuit diagram showing a state in which the electronic brake system according to the embodiment of the present invention is statically braked.
4 is a schematic block diagram of an electronic braking system in accordance with an embodiment of the present invention.
5 is a flowchart illustrating a method of controlling an electronic brake system according to an embodiment of the present invention.
6 is a flowchart illustrating a method of controlling an electronic brake system according to an embodiment of the present invention.
7 is a flowchart illustrating a method of controlling an electronic brake system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided to fully convey the spirit of the present invention to a person having ordinary skill in the art to which the present invention belongs. The present invention is not limited to the embodiments shown herein but may be embodied in other forms. For the sake of clarity, the drawings are not drawn to scale, and the size of the elements may be slightly exaggerated to facilitate understanding.

1 is a hydraulic circuit diagram showing a state of the electromagnetic brake system 1 according to an embodiment of the present invention at the time of non-braking.

1, the electronic brake system 1 typically includes a master cylinder 20 for generating hydraulic pressure, a reservoir 30 coupled to the top of the master cylinder 20 for storing oil, a brake pedal (not shown) An input rod 12 which pressurizes the master cylinder 20 in accordance with the pressing force of the brake pedal 10 and a wheel cylinder 40 which transmits hydraulic pressure to brake the wheels RR, RL, FR and FL, A pedal displacement sensor 11 for detecting the displacement of the brake pedal 10 and a simulation device 50 for providing a reaction force in response to the power of the brake pedal 10.

The master cylinder 20 may be configured to include at least one chamber to generate hydraulic pressure. In one example, the master cylinder 20 is configured to have two chambers, each chamber being provided with a first piston 21a and a second piston 22a, the first piston 21a being connected to the input rod 12 ).

On the other hand, the master cylinder 20 has two chambers to ensure safety in case of failure. For example, one of the two chambers may be connected to the right front wheel FR and the left rear wheel RL of the vehicle, and the other chamber may be connected to the left front wheel FL and the right rear wheel RR. Alternatively, one of the two chambers may be connected to the two front wheels FR and FL and the other chamber to the two rear wheels RR and RL. Thus, by independently configuring the two chambers, it is possible to braking the vehicle even if one of the chambers fails.

To this end, the master cylinder 20 may be formed with first and second hydraulic ports 24a and 24b, respectively, through which fluid pressure is discharged from the two chambers.

A first spring 21b is provided between the first piston 21a and the second piston 22a of the master cylinder 20 and a second spring 21b is provided between the end of the master cylinder 20 and the second piston 22a. 2 spring 22b may be provided.

The first spring 21b and the second spring 22b are respectively provided in the two chambers and as the displacement of the brake pedal 10 changes, the first piston 21a and the second piston 22a are compressed, The elastic force is stored in the spring 21b and the second spring 22b. When the pushing force of the first piston 21a becomes smaller than the elastic force, the first and second pistons 21a and 22a are returned to the original state by using the elastic force stored in the first spring 21b and the second spring 22b .

On the other hand, the input rod 12 for pressing the first piston 21a of the master cylinder 20 can be brought into contact with the first piston 21a in close contact with each other. That is, a gap between the master cylinder 20 and the input rod 12 may not exist. Therefore, when the brake pedal 10 is depressed, the master cylinder 20 can be directly pressed without a pedal invalid stroke section.

The simulation apparatus 50 may be connected to a first backup passage 251 to be described later to provide a reaction force according to the pressing force of the brake pedal 10. The reaction force is provided as much as the driver's compensation is compensated for, so that the driver can finely adjust the braking force as intended.

1, the simulation apparatus 50 includes a simulation chamber 51 configured to store oil flowing out from the first hydraulic port 24a of the master cylinder 20 and a reaction force piston (not shown) provided in the simulation chamber 51 And a simulator valve 54 connected to the pedal simulator and the rear end of the simulation chamber 51. The simulator valve 54 is connected to the rear end of the simulation chamber 51,

The reaction force piston 52 and the reaction force spring 53 are installed so as to have a certain range of displacement in the simulation chamber 51 by the oil introduced into the simulation chamber 51.

On the other hand, the reaction force spring 53 shown in the drawing is only one embodiment capable of providing an elastic force to the reaction force piston 52, and may include various embodiments capable of storing the elastic force by deforming the shape. For example, it includes various members capable of storing an elastic force by being made of a material such as rubber or having a coil or a plate shape.

The simulator valve 54 may be provided in a flow path connecting the rear end of the simulation chamber 51 and the reservoir 30. [ The front end of the simulation chamber 51 is connected to the master cylinder 20 and the rear end of the simulation chamber 51 can be connected to the reservoir 30 through the simulator valve 54. Therefore, even when the reaction force piston 52 returns, oil in the reservoir 30 flows through the simulator valve 54, so that the entire interior of the simulation chamber 51 can be filled with the oil.

In the meantime, several reservoirs 30 are shown in the figure, and each reservoir 30 uses the same reference numerals. However, these reservoirs may be provided with the same parts or may be provided with different parts. For example, the reservoir 30 connected to the simulation apparatus 50 can store the oil separately from the reservoir 30 connected to the master cylinder 20, or to the reservoir 30 connected to the master cylinder 20 It can be a repository.

On the other hand, the simulator valve 54 may be constituted by a normally closed type solenoid valve that keeps the normally closed state. The simulator valve 54 can be opened when the driver applies pressure to the brake pedal 10 to deliver the brake fluid between the simulation chamber 51 and the reservoir 30. [

Further, a simulator check valve 55 may be provided between the pedal simulator and the reservoir 30 so as to be connected to the simulator valve 54 in parallel. The simulator check valve 55 allows the oil of the reservoir 30 to flow into the simulation chamber 51 while the oil of the simulation chamber 51 flows into the reservoir 30 through the flow path in which the check valve 55 is installed You can block things. A quick return of the pedal simulator pressure can be ensured since the oil can be supplied into the simulation chamber 51 through the simulator check valve 55 when the brake pedal 10 is depressed.

The simulating chamber 51 which pushes the reaction force spring 53 while compressing the reaction force piston 52 of the pedal simulator when the driver applies the pressing force to the brake pedal 10 will be described. Is delivered to the reservoir 30 through the simulator valve 54, in which the driver is provided with a feeling of a pedal. When the driver releases his / her foot to the brake pedal 10, the reaction force spring 52 pushes the reaction force piston 52 to return the reaction force piston 52 to its original state, and the oil of the reservoir 30 is returned to the simulator valve 54 may flow into the simulation chamber 51 through the flow path where the check valve 55 and the check valve 55 are installed, so that the oil can be filled in the simulation chamber 51.

Since the inside of the simulation chamber 51 is filled with oil at all times, friction of the reaction force piston 52 is minimized during operation of the simulation apparatus 50 to improve the durability of the simulation apparatus 50, Can be blocked.

An electronic brake system 1 according to an embodiment of the present invention includes a hydraulic pressure supply device 100 (hereinafter, referred to as " brake ") that receives mechanical signals of a driver's braking intent from a pedal displacement sensor 11 that senses displacement of a brake pedal 10, And first and second hydraulic circuits 201 and 202 for controlling the flow of hydraulic pressure transmitted to the wheel cylinders 40 provided in the two wheels RR, RL, FR and FL, respectively, A first cut valve 261 provided in a first backup passage 251 for connecting the first hydraulic pressure port 24a and the first hydraulic circuit 201 to control the flow of hydraulic pressure, A second cut valve 262 provided on a second backup passage 252 connecting the hydraulic port 24b and the second hydraulic circuit 202 to control the flow of the hydraulic pressure, An electronic control unit (ECU) 100 for controlling the supply device 100 and the valves 54, 221, 222, 223, 224, 231, 232, 241, 242, 261, 0).

The hydraulic pressure supply device 100 includes a pressure providing unit 110 that provides oil pressure to be transmitted to the wheel cylinder 40, a motor 120 that generates a rotational force by an electrical signal of the pedal displacement sensor 11, And a power converting unit 130 converting the rotational motion of the motor 120 into a linear motion and transmitting the linear motion to the pressure providing unit 110.

The pressure providing unit 110 includes a pressure chamber 111 in which a predetermined space is formed for storing and storing oil, a hydraulic piston 112 provided in the pressure chamber 111, a hydraulic piston 112 and a pressure chamber 111 And a hydraulic spring 122 for elastically supporting the hydraulic piston 112. As shown in FIG.

The pressure chamber 111 is connected to the reservoir 30 by the oil passage 114 and can receive and store the oil from the reservoir 30. The oil passage 114 may communicate with the first communication hole 111a formed at the inlet side of the pressure chamber 111. [ For example, the first communication hole 111a may be formed at the inlet side of the pressure chamber 111 where pressure is generated when the hydraulic piston 112 advances.

The oil passage 114 may be provided with a check valve 115 for preventing the pressure of the pressure chamber 111 from flowing backward. The check valve 115 prevents the oil in the pressure chamber 111 from being lost to the reservoir 30 through the oil passage 114 when the hydraulic piston 112 is advanced and prevents the oil pressure piston 112 from returning to the reservoir 30 is sucked and stored at the inlet side of the pressure chamber 111. [

The hydraulic pressure supply device 100 can also be configured to prevent the pressure in the pressure chamber 111 from being released to the atmospheric pressure in the process of returning the hydraulic piston 112 and absorbing the hydraulic pressure in the pressure chamber 111 . A second communication hole 111b is formed in the pressure chamber 111 and a second communication hole 111b and an oil passage 114 are formed between the outlet side of the pressure chamber 111 and the oil passage 114. [ A connecting flow passage 116 is formed. At this time, the second communication hole 111b is located at the initial position of the hydraulic piston 112 (i.e., when the hydraulic piston 112 retracts to the outlet side of the pressure chamber 111 and the pressure in the pressure chamber 111 is released) (I.e., the position of the hydraulic piston 112). Accordingly, the hydraulic piston 112 is returned, and the outlet side of the compression chamber 111 is automatically connected to the reservoir 30 through the connection passage 116, so that the pressure can be returned to the atmospheric pressure.

The motor 120 is a device that generates a rotational force by a signal output from the electronic control unit 1000 and can generate a rotational force in a forward or reverse direction. The rotational angular velocity and rotational angle of the motor 120 can be precisely controlled. Since the motor 120 is a well-known technology, its detailed description will be omitted.

On the other hand, the electronic control unit 1000 controls the valves included in the electronic brake system 1 of the present invention, including the motor 120, to be described later. The operation in which a plurality of valves are controlled according to the displacement of the brake pedal 10 will be described later.

The driving force of the motor 120 causes the displacement of the hydraulic piston 112 through the power conversion unit 130 and the hydraulic pressure generated by the sliding movement of the hydraulic piston 112 in the pressure chamber 111, RL, FR, FL through the two hydraulic oil passages 211, 212. The wheel cylinders 40,

The power converting unit 130 is a device for converting the rotational force into a linear motion. The power converting unit 130 may include a worm shaft 131, a worm wheel 132, and a drive shaft 133, for example.

The worm shaft 131 may be formed integrally with the rotation shaft of the motor 120, and is formed with a worm on the outer circumferential surface thereof to be engaged with the worm wheel 132 to rotate the worm wheel 132. The worm wheel 132 is connected to the drive shaft 133 to linearly move the drive shaft 133 and the drive shaft 133 is connected to the piston 111 to slide the piston 111 in the pressure chamber 111 .

A signal sensed by the pedal displacement sensor 11 is transmitted to the electronic control unit 1000 and the electronic control unit 1000 is controlled by the motor 120. [ The worm shaft 131 is rotated in one direction. The rotational force of the worm shaft 131 is transmitted to the drive shaft 133 via the worm wheel 132 and the hydraulic piston 112 connected to the drive shaft 133 moves to generate a hydraulic pressure in the pressure chamber 111.

On the contrary, when the brake pedal 10 is depressed, the electronic control unit 1000 drives the motor 120 in the opposite direction, and the worm shaft 131 rotates in the opposite direction. Accordingly, the worm wheel 132 also rotates in the opposite direction and the hydraulic piston 112 connected to the drive shaft 133 returns. At this time, the hydraulic spring 113 can quickly suck the hydraulic pressure in the pressure chamber 111 by providing an elastic force to the hydraulic piston 112.

The hydraulic pressure supply device 100 transfers the hydraulic pressure to the wheel cylinder 40 or sucks the hydraulic pressure to the reservoir 30 according to the rotational direction of the rotational force generated from the motor 120.

Alternatively, although not shown in the drawings, the power conversion unit 130 may be constituted by a ball screw nut assembly. For example, a screw formed integrally with the rotating shaft of the motor 120 or connected to rotate as the rotating shaft of the motor 120, and a ball nut screwed with the screw in a limited rotation state and linearly moving according to the rotation of the screw . The hydraulic pressure piston 112 is connected to the ball nut of the power converting unit 130 to press the pressure chamber 111 by the linear movement of the ball nut, And serves to return the piston 112 to its original position. The structure of such a ball screw nut assembly is a device that converts rotational motion into linear motion and is a well-known technique that has been well known in the art, and thus a detailed description thereof will be omitted.

In addition, it should be understood that the power converting unit 130 according to the embodiment of the present invention can adopt any structure as long as it can convert rotational motion into linear motion in addition to the structure of the ball screw nut assembly.

Next, the hydraulic control unit 200 according to an embodiment of the present invention will be described with reference to FIG.

The hydraulic control unit 200 may include a first hydraulic circuit 201 and a second hydraulic circuit 202, each of which receives hydraulic pressure and controls two wheels, respectively. For example, the first hydraulic circuit 201 controls the right front wheel FR and the left rear wheel RL, and the second hydraulic circuit 202 can control the left front wheel FL and the right rear wheel RR . The wheel cylinders 40 are provided on the respective wheels FR, FL, RR, and RL to supply hydraulic pressure to perform braking.

The hydraulic control unit 200 includes a first hydraulic oil path 211 connecting the first hydraulic circuit 201 and the hydraulic pressure supply device 100 and a second hydraulic oil path 211 connected to the second hydraulic circuit 202, 212 to receive the hydraulic pressure from the hydraulic pressure supply device 100. At this time, the second hydraulic oil path 212 may be connected to the branch path 214 branched from the first hydraulic fluid path 211.

The first and second hydraulic oil passages 211 and 212 are connected to each other via the branch passage 214 and receive hydraulic pressure from the hydraulic pressure supply device 100 to be connected to the wheel cylinders 40 of the hydraulic circuits 201 and 202 . At this time, each of the hydraulic circuits 201 and 202 may have a plurality of inlet valves 221 to control the flow of hydraulic pressure.

For example, the first hydraulic circuit 201 may be provided with two inlet valves 221 connected to the first hydraulic oil path 211 and controlling the hydraulic pressures transmitted to the two wheel cylinders 40, respectively. The second hydraulic circuit 202 may be provided with two inlet valves 221 connected to the second hydraulic oil path 212 and controlling the hydraulic pressures transmitted to the wheel cylinders 40, respectively.

The plurality of inlet valves 221 are disposed on the upstream side of the wheel cylinders 40 and are normally open. Normally open type solenoid valves (not shown) operate to close the valves when receiving a closing signal from the electronic control unit 1000 .

The hydraulic control unit 200 may further include a plurality of outlet valves 222 connected to the reservoir 30 for improving the braking performance. The outlet valve 222 is connected to the wheel cylinder 40 to control the hydraulic pressure from the wheels RR, RL, FR and FL, respectively. That is, the outlet valve 222 senses the braking pressure of each of the wheels RR, RL, FR and FL and is selectively opened to control the pressure when the pressure reduction braking is required.

And the outlet valve 222 may be provided as a solenoid valve of a normal closed type which is normally closed and operates to open the valve when receiving an open signal from the electronic control unit 1000.

The electromagnetic brake system 1 according to the embodiment of the present invention includes a first switching valve 231 provided in the first hydraulic fluid path 211 and a second switching valve 231 provided in the second hydraulic fluid path 212, (232).

The first and second switching valves 231 and 232 may be independently controlled, and may be a normally closed type (normally closed type) solenoid valve which is normally closed and operates to open the valve when an open signal is received. The first and second switching valves 231 and 232 are selectively opened and closed according to the required pressure to control the flow of the hydraulic pressure transmitted to the wheel cylinder 40. For example, when hydraulic pressure is to be supplied only to the wheel cylinders 40 provided in the first hydraulic circuit 201, only the first switching valve 231 is opened so that the hydraulic pressure discharged through the hydraulic pressure supply device 100 is supplied to the second hydraulic circuit 202 to the first hydraulic circuit 201 without being transmitted to the first hydraulic circuit 201. The operation structure of the first and second switching valves 231 and 232 will be described below again.

The electromagnetic brake system 1 according to an embodiment of the present invention may include a release valve 233 for controlling the brake pedal 10 to follow a target pressure value when a pressure of the brake pedal 10 is higher than a set target pressure value, ).

The release valve 233 may be provided in a flow path connecting the branch passage 214 connecting the two hydraulic circuits 201 and 202 to the valve 30. That is, the release valve 233 may be provided between the first and second switching valves 231 and 232 and the hydraulic pressure supply device 100. The release valve 233 may be a normally closed type (normally closed type) solenoid valve that is normally closed and operates to open the valve when an open signal is received.

The electromagnetic brake system 1 according to the embodiment of the present invention includes first and second backup oil passages 251 and 252 capable of supplying the oil discharged from the master cylinder 20 to the wheel cylinder 40 when the oil brake system is operating abnormally, 252).

A first cut valve 261 for controlling the flow of oil is provided in the first backup passage 251 and a second cut valve 262 for controlling the flow of oil is provided in the second backup passage 252 have. The first backup hydraulic passage 251 connects the first hydraulic pressure port 24a and the first hydraulic pressure circuit 201 and the second backup hydraulic passage 252 connects the second hydraulic pressure port 25b and the second hydraulic circuit 202 can be connected.

The first and second cut valves 261 and 262 are normally open type solenoid valves that are opened in a normal state and operated to close a valve when the electronic control unit 1000 receives a close signal . The operation structure of the first and second cut valves 261 and 262 will be described below again.

Reference numeral " PS11 " is a first hydraulic oil pressure sensor for sensing the hydraulic pressure of the first hydraulic circuit 201, "PS12" is a second hydraulic oil for sensing the hydraulic pressure of the second hydraulic circuit 202, Quot; PS2 "is a back-up hydraulic pressure sensor for measuring the oil pressure of the master cylinder 20. [ And "MPS" is a motor control sensor for controlling the rotation angle of the motor 120 or the current of the motor.

Hereinafter, the operation of the electronic brake system 1 according to the embodiment of the present invention will be described in detail.

2 is a hydraulic circuit diagram showing a state in which the electronic brake system 1 according to the embodiment of the present invention is normally braked and operated.

Referring to FIG. 2, when the braking by the driver is started, the amount of brake demand of the driver can be sensed through the pedal displacement sensor 11 through information such as the pressure of the brake pedal 10 depressed by the driver. The electronic control unit 1000 receives the electric signal output from the pedal displacement sensor 11 and drives the motor 120. [

The electronic control unit 1000 further includes a backup hydraulic pressure sensor PS2 provided at the outlet side of the master cylinder 20 and first and second hydraulic oil pressure sensors provided in the first and second hydraulic circuits 201, (PS11, PS12), and calculates the magnitude of the friction damping amount according to the difference between the demand braking amount and the regenerating braking amount of the driver to determine the magnitude of the pressure increase or the pressure decrease of the wheel cylinder (40) .

Specifically, when the driver depresses the brake pedal 10 at the beginning of the braking operation, the motor 120 is actuated. The rotational force of the motor 120 is transmitted to the pressure providing unit 110 by the power transmitting portion 130, The hydraulic pressure discharged from the providing unit 110 is transmitted to the first hydraulic oil path 211 and the second hydraulic oil path 212. [

On the other hand, when hydraulic pressure is generated in the hydraulic pressure supply device 100, the first and second hydraulic oil passages 251 and 252 connected to the first and second hydraulic ports 24a and 24b of the master cylinder 20, The second cut valves 261 and 262 are closed so that the hydraulic pressure discharged from the master cylinder 20 is not transmitted to the wheel cylinder 40.

The hydraulic pressure discharged from the hydraulic pressure supply device 100 is transmitted to the wheel cylinders 40 provided on the respective wheels RR, RL, FR and FL as the inlet valve 221 is opened to generate the braking force. At this time, when the pressure transmitted to the first and second hydraulic circuits 201 and 202 is measured to be higher than the target pressure value corresponding to the leg power of the brake pedal 10, the release valve 233 is opened to follow the target pressure value .

The pressure generated by the pressing force of the master cylinder 20 according to the pressing force of the brake pedal 10 is transmitted to the simulation apparatus 50 connected to the master cylinder 20. At this time, the normally closed simulator valve 54 disposed at the rear end of the simulation chamber 51 is opened, and the oil filled in the simulation chamber 51 through the simulator valve 54 is transferred to the reservoir 30. Further, a pressure corresponding to the load of the reaction force spring 53, in which the reaction force piston 52 is moved and which supports the reaction force piston 52, is formed in the simulation chamber 51 to provide an appropriate pedal feeling to the driver.

Next, the case of releasing the braking force in the braking state in the normal operation of the electromagnetic brake system 1 according to the embodiment of the present invention will be described. 3 is a hydraulic circuit diagram showing a state in which the electronic brake system 1 according to the embodiment of the present invention is normally released.

3, when the pedal applied to the brake pedal 10 is released, the motor 120 generates a rotational force in a direction opposite to the braking direction and transmits the rotational force to the power converting unit 130, The shaft 131, the worm wheel 132, and the drive shaft 133 rotate in the direction opposite to the braking direction to release the pressure of the pressure providing unit 110 by moving the hydraulic piston 112 back to its original position. The pressure providing unit 110 receives the hydraulic pressure discharged from the wheel cylinder 40 through the first and second hydraulic oil passages 211 and 212 and transmits the hydraulic pressure to the reservoir 30.

On the other hand, the inlet valve 221, the outlet valve 222, the first and second switching valves 231 and 232, the release valve 233, and the first and second cut valves 261 and 262 Closing operation state as in the braking operation. That is, the outlet valve 222, the release valve 233 and the first and second cut valves 261 and 262 are closed and the inlet valve 221 and the first and second switching valves 231 and 232 Is opened. The hydraulic pressure discharged from the wheel cylinders 40 of the first and second hydraulic circuits 201 and 202 is transmitted into the pressure chambers 111 through the first and second hydraulic oil passages 211 and 212.

The simulation apparatus 50 is configured such that the oil in the simulation chamber 51 is transferred to the master cylinder 20 as the reaction force piston 52 is returned to the home position by the elastic force of the reaction force spring 53, A quick return of the pedal simulator pressure is ensured by refilling the oil into the simulation chamber 51 through the connected simulator valve 54 and simulator check valve 55.

The oil flow in the pressure chamber 111 when the hydraulic piston 112 moves through the hydraulic pressure supply device 100 can be controlled through the oil passage 114 and the connecting passage 116 connected to the reservoir 30 .

The electronic brake system 1 according to the embodiment of the present invention is also applicable to the wheel cylinders 40 provided in the respective wheels RR, RL, FR, FL of the two hydraulic circuits 201, It is possible to specify and control the control range by controlling the valves 221 and 222 provided in the hydraulic control unit 200.

4 is a schematic block diagram of an electronic braking system in accordance with an embodiment of the present invention.

4, the electronic brake system 1 of the vehicle includes a pressure measurement unit 35 for sensing the fluid pressure in the hydraulic system, a pedal input unit 36 for sensing the pedal input of the driver, An electronic control unit 1000 and a plurality of valves 1100 and a motor 120 in a hydraulic circuit driven in accordance with a control signal calculated in the electronic control unit 1000. [

The pressure measuring section 35 includes a plurality of pressure sensors. Specifically, a pressure sensor (not shown) included in each of the wheels FR, FL, RR, and RL and a first hydraulic oil pressure sensor 31 for detecting the hydraulic pressure of the first hydraulic circuit 201 by the PS 11 shown in Figs. A second hydraulic oil pressure sensor PS12 for sensing the hydraulic pressure of the second hydraulic circuit 202 and a backup hydraulic pressure sensor PS2 for measuring the oil pressure of the master cylinder 20. [

Therefore, the pressure measured by the plurality of pressure sensors included in the pressure measuring section 35 can be transmitted to the electronic control unit 1000. [

Next, the pedal input unit 36 detects the pedal input of the driver. Specifically, the amount of brake demand by the driver can be sensed through the pedal displacement sensor 11 shown in FIG. 1, based on information such as the pressure of the brake pedal 10 depressed by the driver.

Therefore, the pressure measured by the pedal displacement sensor included in the pedal input section 36 can be transmitted to the electronic control unit 1000. [

Next, the electronic control unit 1000 collectively controls the electronic brake system 1 of the vehicle according to the present invention.

Specifically, the electronic control unit 1000 stores a main processor 15 for detecting the driver's braking effort and braking amount from the pedal input unit 36 and calculating the braking pressure corresponding to the driver's requested braking pressure, And a memory 25 for storing the data.

The main processor 31 in the electronic control unit 1000 can control the operation of the plurality of valves 1100 and the motor 120 included in the electronic brake system 1. [

Specifically, the main processor 15 drives the plurality of valves 1100 in order to operate the motor 120 to generate a braking pressure corresponding to the braking will of the driver when the pedaling force of the driver is applied from the pedal input unit 36 do.

At this time, it is possible to receive a pressure value measured in real time from a plurality of pressure sensors included in the pressure measuring section 35. [

For example, when the pedaling force of the driver is applied from the pedal input section 36, the motor 120 is operated and the hydraulic pressure of the master cylinder must increase or decrease as the plurality of valves 1100 operate. Therefore, at this time, if the pressure change amount of the master cylinder is smaller than a preset threshold value, it can be determined that a leak of the valve has occurred.

 However, it is not possible to specify a valve in which a leak occurs in the plurality of valves 1100.

In addition, for example, when the driver's pedal pressure is applied from the pedal input portion 36 and the plurality of outlet valves 222 shown in Fig. 1 are opened when the braking is performed, each wheel is connected to the wheel cylinder 40, RR, RL, FR, FL). That is, the outlet valve 222 senses the braking pressure of each of the wheels RR, RL, FR and FL and is selectively opened to control the pressure when the pressure reduction braking is required.

However, if the measured wheel pressure does not decrease even though the outlet valve 222 is open, it can be determined that a stuck phenomenon occurs in the outlet valve 222.

In addition, the hydraulic pressure of the hydraulic circuit can be changed under the control of the main processor 15. [ Specifically, the hydraulic pressure can be estimated according to the drive duty control of the motor 120, the drive time of the motor, the drive signal (On / Off) of the plurality of valves 1100, and the drive time of each valve.

For example, when the duty ratio of the motor 120 is sampled by 1% to 100% in units of 10%, and the number of the plurality of valves 1100 included in the hydraulic circuit shown in FIG. 1 is 15, Is 2 ¹⁵ * 10, and 327680 kinds of hydraulic pressure estimation values can be data.

Accordingly, the main processor 15 can control the driving duty of the motor 120, the driving time of the motor, the driving signals (On / Off) of the plurality of valves 1100, When the error between the previously stored estimated hydraulic pressure and the actual measured hydraulic pressure is greater than a predetermined threshold value during braking according to the actual electronic brake system 1 according to the present invention, It can be judged as a failure.

Next, the memory 25 in the electronic control unit 1000 is followed by a nonvolatile memory such as a S-RAM or a D-RAM, as well as a flash memory, a ROM (Read Only Memory) A non-volatile memory such as an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or the like.

The non-volatile memory may semi-permanently store a control program and control data for controlling the operation of the electronic brake system 1, and the volatile memory may temporarily store control programs and control data from the non-volatile memory, Sensor information and various control signals output from the main processor can be temporarily stored.

The configuration of the electromagnetic brake system 1 according to the present invention has been described above.

5 to 7 are flowcharts of a control method of the electronic brake system 1 according to the present invention.

5, when the driver depresses the brake pedal 10, the electronic control unit 1000 detects the driver's pedal input based on the pedal stroke detected through the pedal displacement sensor 11 S10)

Accordingly, the electronic brake system 1 operates the motor 120 to output braking pressure corresponding to the braking will of the driver (S20). In addition to the operation of the motor 120, the electronic control unit 1000 drives the plurality of valves 110 included in the electronic brake system 1 to perform braking control.

At this time, the pressure measurement unit 35 in the electronic brake system 1 measures the pressure in the hydraulic circuit (S30). Specifically, the pressure measuring section 35 includes a pressure sensor (not shown) included in each of the wheels FR, FL, RR, RL to measure the pressure of each wheel, The PS 11 senses the hydraulic pressure of the first hydraulic circuit 201 or the PS 12 senses the hydraulic pressure of the second hydraulic circuit 202 and the PS 2 can measure the oil pressure of the master cylinder 20.

If the pressure change amount of the master cylinder is smaller than the predetermined first threshold value although the hydraulic pressure of the master cylinder must increase or decrease as the plurality of valves 1100 of the electromagnetic brake system 1 operate S40), it is determined that the valve has failed (S50). The driver can be warned by detecting an error in the electronic brake system 1 (S60).

However, it is not possible to specify a valve in which a failure has occurred among a plurality of valves 1100.

 6, when the driver depresses the brake pedal 10, the electronic control unit 1000 detects the driver's pedal input based on the pedal stroke detected through the pedal displacement sensor 11 (S11)

Accordingly, the electronic brake system 1 operates the motor 120 to output braking pressure corresponding to the braking will of the driver (S21). In addition to the operation of the motor 120, the electronic control unit 1000 drives the plurality of valves 110 included in the electronic brake system 1 to perform braking control.

At this time, the pressure measurement unit 35 in the electronic brake system 1 measures the pressure in the hydraulic circuit (S31). Specifically, the pressure measuring section 35 includes a pressure sensor (not shown) included in each of the wheels FR, FL, RR, RL to measure the pressure of each wheel, The PS 11 senses the hydraulic pressure of the first hydraulic circuit 201 or the PS 12 senses the hydraulic pressure of the second hydraulic circuit 202 and the PS 2 can measure the oil pressure of the master cylinder 20.

The electronic control unit 1000 is connected to the wheel cylinders 40 and outputs hydraulic pressure from the respective wheels RR, RL, FR, FL to the wheel cylinders 40 when the plurality of outlet valves 222 are opened (S41) Can be controlled.

However, if the wheel pressure is reduced (S51) even though the plurality of outlet valves 222 are open, it can be determined that the valve has failed (S61). Specifically, the electronic main processor 15 can determine that a stuck phenomenon of the outlet valve has occurred.

 The driver can be warned by detecting an error in the electronic brake system 1 (S71).

7, when the driver depresses the brake pedal 10, the electronic control unit 1000 detects the driver's pedal input based on the pedal stroke detected through the pedal displacement sensor 11 (S12)

Accordingly, the electronic brake system 1 operates the motor 120 to output the braking pressure corresponding to the braking will of the driver (S22). In addition to the operation of the motor 120, the electronic control unit 1000 drives the plurality of valves 110 included in the electronic brake system 1 to perform braking control.

At this time, the pressure measurement unit 35 in the electronic brake system 1 measures the pressure in the hydraulic circuit (S32). Specifically, the pressure measuring section 35 includes a pressure sensor (not shown) included in each of the wheels FR, FL, RR, RL to measure the pressure of each wheel, The PS 11 senses the hydraulic pressure of the first hydraulic circuit 201 or the PS 12 senses the hydraulic pressure of the second hydraulic circuit 202 and the PS 2 can measure the oil pressure of the master cylinder 20.

Although not shown, the electronic control unit 1000 controls the drive duty of the motor 120, the drive time of the motor, the drive signals (On / Off) of the plurality of valves 1100, The hydraulic pressure can be estimated according to the time, and the estimated hydraulic pressure according to each situation can be stored in the memory 25. [

Therefore, when the error between the pressure value measured by the pressure measuring section 35 and the previously-stored estimated pressure value is larger than the second threshold value (YES in S42), the electronic control unit 1000) is judged to be a valve failure (S52). The driver can be warned by detecting an error in the electronic brake system 1 (S62).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limited to the embodiments set forth herein; It will be understood that various modifications may be made without departing from the spirit and scope of the invention.

Claims (8)

A master cylinder for discharging oil according to an urging force of the brake pedal;
A pedal displacement sensor for sensing a displacement of the brake pedal;
A hydraulic pressure supply device for generating a hydraulic pressure using a rotational force of a motor operated by an electrical signal output from the pedal displacement sensor;
A hydraulic pressure control unit for transmitting hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided in each wheel;
A plurality of pressure sensors for measuring the hydraulic pressure in the hydraulic control unit;
And an electronic control unit for controlling the motor and the valves based on the hydraulic pressure information and the displacement information of the brake pedal, the electronic braking system comprising:
Wherein the electronic control unit determines that the valve malfunctions if an error between the measured hydraulic pressure and a predetermined estimated hydraulic pressure is equal to or greater than a first threshold value set in advance. The method according to claim 1,
Wherein the electronic control unit stores in advance the estimated hydraulic pressure information according to the drive time of the motor, whether the valve is open or closed, and the drive time of the valve. 3. The method of claim 2,
Wherein the electronic control unit is further operable to determine that the valve is in failure when the pressure of the brake pedal is applied and the amount of change in the hydraulic pressure in the hydraulic control unit is smaller than a second predetermined threshold, system. The method of claim 3,
The hydraulic control unit
Further comprising an outlet valve for controlling the fluid pressure of the wheel cylinder to escape,
Wherein the electronic control unit further determines that the outlet valve fails if the hydraulic pressure of the wheel cylinder does not decrease when the outlet valve is opened. A master cylinder for discharging oil according to an urging force of the brake pedal;
A pedal displacement sensor for sensing a displacement of the brake pedal;
A hydraulic pressure supply device for generating a hydraulic pressure using a rotational force of a motor operated by an electrical signal output from the pedal displacement sensor;
A hydraulic pressure control unit for transmitting hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided in each wheel;
A plurality of pressure sensors for measuring the hydraulic pressure in the hydraulic control unit;
And an electronic control unit for controlling the motor and the valves based on the hydraulic pressure information and the displacement information of the brake pedal, the electronic braking system comprising:
Wherein the electronic control unit determines that the valve is in failure if the error between the measured hydraulic pressure and a predetermined estimated hydraulic pressure is equal to or greater than a first threshold value set in advance. 6. The method of claim 5,
Wherein the predetermined estimated hydraulic pressure is determined according to a driving time of the motor, whether or not the valve is opened and closed, and a driving time of the valve. The method according to claim 6,
Wherein when the pressure of the brake pedal is applied and the change amount of the hydraulic pressure in the hydraulic pressure control unit is smaller than a second threshold value set in advance when the motor is in operation, the valve is further determined as a failure. 8. The method of claim 7,
Wherein an outlet valve for controlling the fluid pressure of the wheel cylinder is opened and the hydraulic pressure of the wheel cylinder is not decreased, the outlet valve is further determined as a failure.

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