KR102421448B1 - Electric brake system and method thereof - Google Patents

Abstract

An electronic brake system is disclosed. The electronic brake system according to an embodiment of the present invention includes a master cylinder that discharges oil according to a pedal effort of a brake pedal, a reservoir connected to the master cylinder and storing oil, and an electrical signal output from a pedal position sensor. A hydraulic pressure supply device for generating hydraulic pressure using rotational force, a first hydraulic circuit for transferring hydraulic pressure discharged from the hydraulic pressure supply device to wheel cylinders provided on at least one wheel, and a hydraulic pressure supply device for supplying hydraulic pressure discharged from the hydraulic pressure supply device to at least one wheel In the electronic brake system comprising a; a second hydraulic circuit for transmitting to the provided wheel cylinder, the motor position sensor for measuring the position of the motor, the first pressure sensor for measuring the hydraulic pressure, and the motor position sensor values are discharged from the piston A control unit for estimating the flow rate used, estimating the flow rate flowing into the wheel based on the measured hydraulic pressure, and comparing the flow rate discharged from the piston with the flow rate flowing into the wheel to determine whether the electronic brake system has a leak further includes

Description

Electronic brake system and method thereof

The present invention relates to an electronic brake system, and more particularly, to an electronic brake system that generates a braking force using an electrical signal corresponding to a displacement of a brake pedal.

A vehicle is necessarily equipped with a brake system for braking. Recently, various types of systems for obtaining a more powerful and stable braking force have been proposed.

An example of the brake system is an anti-lock brake system (ABS) that prevents wheel slipping during braking, and a brake traction control system (BTCS: Brake) that prevents slipping of the driving wheels when the vehicle starts or accelerates rapidly. Traction Control System), and Electronic Stability Control System (ESC), which controls the brake fluid pressure by combining an anti-lock brake system and traction control to maintain a stable driving state of the vehicle.

In general, an electronic brake system includes a hydraulic pressure supply device for supplying pressure to wheel cylinders by receiving the driver's braking intention as an electrical signal from a pedal displacement sensor that senses the displacement of the brake pedal when the driver steps on the brake pedal.

The electronic brake system provided with the above hydraulic pressure supply device is disclosed in European Patent Registration No. EP 2 520 473. According to the disclosed document, the hydraulic pressure supply device is configured to generate a braking pressure by operating a motor according to a pedal force of a brake pedal. At this time, the braking pressure is generated by converting the rotational force of the motor into a linear motion and pressurizing the piston.

In addition, the brake system includes a pedal simulator that provides a feeling of pedaling to the driver by receiving hydraulic pressure according to the driver's pedal effort in order to measure the pedal effort.

Therefore, the electronic brake system provided with the hydraulic pressure supply device not only generates braking pressure based on the sensor value of the pedal position sensor obtained with respect to the pedal effort applied by the driver, but also operates the pedal simulator based on the pedal position sensor value. .

However, in the electronic brake system, research on a method for determining a case of leakage has been continuously conducted.

EP 2 520 473 A1 (Honda Motor Co., Ltd.) 2012. 11. 7.

An embodiment of the present invention is to provide an electronic brake system capable of determining a leak even when ABS is in operation.

According to one aspect of the present invention, there is provided a master cylinder for discharging oil according to a pedal effort of a brake pedal; a reservoir connected to the master cylinder and storing oil; a hydraulic pressure supply device for generating hydraulic pressure using a rotational force of the motor operated by an electrical signal output from the pedal position sensor; a first hydraulic circuit for transferring the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided on at least one wheel; and a second hydraulic circuit for transferring the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided on at least one wheel;

a first pressure sensor for measuring hydraulic pressure; and estimating the flow rate discharged from the piston based on the motor position sensor value, estimating the flow rate flowing into the wheel based on the measured hydraulic pressure, and comparing the flow rate discharged from the piston with the flow rate flowing into the wheel. The electronic brake system may further include a control unit that determines whether or not a leak occurs.

In addition, when the ratio of the flow rate discharged from the piston to the flow rate flowing into the wheel is greater than a first threshold value, it may be determined as a leak of the electronic brake system.

In addition, the control unit may determine that a leak has occurred in the electronic brake system, and if the slip value of the at least one or more wheels is smaller than a preset threshold value, it may be determined as the leak in the wheel.

In addition, the first hydraulic circuit further includes at least one or more inlet valves for adjusting the flow rate discharged from the hydraulic pressure supply device, and the second hydraulic circuit is for adjusting the flow rate discharged from the hydraulic pressure supply device. It may further include at least one inlet valve.

Also, the controller may determine a flow rate flowing into the wheel based on a current of the inlet valve and the measured hydraulic pressure.

According to another aspect of the present invention, there is provided a master cylinder for discharging oil according to a pedal effort of a brake pedal; a reservoir connected to the master cylinder and storing oil;

a hydraulic pressure supply device for generating hydraulic pressure using a rotational force of the motor operated by an electrical signal output from the pedal position sensor; a first hydraulic circuit for transferring the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided on at least one wheel; and a second hydraulic circuit for transferring the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided on at least one wheel; a pressure sensor measuring hydraulic pressure; and estimating the flow rate discharged from the piston based on the motor position sensor value, estimating the flow rate flowing into the wheel based on the measured hydraulic pressure, and comparing the flow rate discharged from the piston with the flow rate flowing into the wheel. There may be provided a method of controlling an electronic brake system including; determining whether a leak occurs in the electronic brake system.

In addition, when the ratio of the flow rate discharged from the piston to the flow rate flowing into the wheel is greater than a first threshold value, determining the leakage of the electronic brake system; may further include.

The method may further include a step of determining that a leak has occurred in the electronic brake system, and when the slip value of the at least one or more wheels is less than a preset threshold value, determining the leak in the wheel.

In the embodiment of the present invention, it may be possible to determine a leak even when ABS is in operation.

1 is a hydraulic circuit diagram illustrating a non-braking state of an electronic brake system according to an embodiment of the present invention.
2 and 3 show a state in which the ABS is operated in the electronic brake system according to an embodiment, FIG. 2 shows a situation in which the hydraulic piston selectively brakes while moving forward, and FIG. 3 shows the hydraulic piston selectively while moving backward. It is a hydraulic circuit diagram showing the braking situation.
4 is a configuration diagram illustrating an electronic brake system according to an exemplary embodiment.
5 is an internal block diagram of an electronic brake system according to an exemplary embodiment.
6 is a flowchart illustrating a control method of an electronic brake system according to an exemplary embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are presented in order to sufficiently convey the spirit of the present invention to those of ordinary skill in the art to which the present invention pertains. The present invention is not limited to the embodiments presented herein, and may be embodied in other forms. The drawings may omit the illustration of parts irrelevant to the description in order to clarify the present invention, and may slightly exaggerate the size of the components to help understanding.

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

Referring to FIG. 1 , the electronic brake system 1 typically includes a master cylinder 20 for generating hydraulic pressure, a reservoir 30 coupled to the upper portion of the master cylinder 20 to store oil, and a brake pedal ( 10), the input rod 12 pressurizes the master cylinder 20 according to the pedal force, the wheel cylinder 40 for braking each wheel RR, RL, FR, and FL by transmitting hydraulic pressure, and a brake pedal A pedal displacement sensor 11 for detecting the displacement of (10) and a simulation device 50 for providing a reaction force according to the pedal effort of the brake pedal 10 are provided.

The master cylinder 20 may be configured to include at least one chamber to generate hydraulic pressure. For example, the master cylinder 20 may include a first master chamber 20a and a second master chamber 20b.

Referring to FIG. 1 , the simulation device 50 includes a simulation chamber 51 provided to store oil flowing out from the first hydraulic port 24a of the master cylinder 20 and a reaction force piston provided in the simulation chamber 51 ( 52) and a pedal simulator having a reaction force spring 53 elastically supporting it, and a simulator valve 54 connected to the rear end of the simulation chamber 51.

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

On the other hand, the reaction 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 shape deformation. For example, it includes various members that can store elastic force by being provided with a material such as rubber, or having a coil or 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 may be connected to the master cylinder 20 , and the rear end of the simulation chamber 51 may be connected to the reservoir 30 through the simulator valve 54 . Accordingly, even when the reaction force piston 52 returns, the oil in the reservoir 30 flows in through the simulator valve 54 so that the entire interior of the simulation chamber 51 can be filled with oil.

On the other hand, several reservoirs 30 are shown in the drawing, and each of the reservoirs 30 uses the same reference numerals. However, these reservoirs may be provided with the same part or may be provided with different parts. For example, the reservoir 30 connected to the simulation device 50 may be the same as the reservoir 30 connected to the master cylinder 20 , or may store oil separately from the reservoir 30 connected to the master cylinder 20 . It can be a repository in

Meanwhile, the simulator valve 54 may be configured as a normally closed solenoid valve that maintains a normally closed state. The simulator valve 54 may be opened when the driver applies a pedal force to the brake pedal 10 to deliver oil in the simulation chamber 51 to the reservoir 30 .

Also, a simulator check valve 55 may be installed between the pedal simulator and the reservoir 30 to be connected in parallel with the simulator valve 54 . The simulator check valve 55 allows the oil of the reservoir 30 to flow into the simulation chamber 51 , but the oil in the simulation chamber 51 flows into the reservoir 30 through the flow path in which the check valve 55 is installed. can block it Since oil can be supplied into the simulation chamber 51 through the simulator check valve 55 when the pedal pressure of the brake pedal 10 is released, a quick return of the pedal simulator pressure can be ensured.

The operation of the pedal simulation device 50 will be described. When the driver provides a pedal force to the brake pedal 10 , the reaction force piston 52 of the pedal simulator pushes the reaction force spring 53 while compressing the simulation chamber 51 . The oil inside is delivered to the reservoir 30 through the simulator valve 54, and in this process, the driver is provided with a feeling of pedal. And when the driver releases the pedaling force on the brake pedal 10, the reaction force spring 53 pushes the reaction force piston 52, and the reaction force piston 52 returns to its original state, and the oil in the reservoir 30 moves to the simulator valve ( The oil may be filled in the simulation chamber 51 as it flows into the simulation chamber 51 through the passage in which 54 is installed and the passage in which the check valve 55 is installed.

As such, since the inside of the simulation chamber 51 is always filled with oil, friction of the reaction force piston 52 is minimized when the simulation device 50 is operated, so that the durability of the simulation device 50 is improved, as well as foreign substances from the outside. inflow may be blocked.

The electronic brake system 1 according to the embodiment of the present invention is a hydraulic pressure supply device 100 that receives the driver's braking intention as an electrical signal from the pedal displacement sensor 11 that detects the displacement of the brake pedal 10 and operates mechanically. ) and first and second hydraulic circuits 201 and 202 for controlling the flow of hydraulic pressure delivered to the wheel cylinders 40 provided on the two wheels RR, RL, FR, and FL, respectively. 200, a first cut valve 261 provided in the first backup flow path 251 connecting the first hydraulic port 24a and the first hydraulic circuit 201 to control the flow of hydraulic pressure, and the second A second cut valve 262 provided in the second backup flow path 252 connecting the hydraulic port 24b and the second hydraulic circuit 202 to control the flow of hydraulic pressure, and hydraulic pressure information and pedal displacement information based on hydraulic pressure information An electronic control unit (ECU, not shown) for controlling the supply device 100 and the valves 54, 60, 221a, 221b, 221c, 221d, 222a, 222b, 222c, 222d, 233, 235, 236, 243 may include

The hydraulic pressure supply device 100 includes a hydraulic pressure supply unit 110 that provides oil pressure transferred to the wheel cylinder 40 , a motor 120 that generates a rotational force by an electrical signal from the pedal displacement sensor 11 , and a motor It may include a power conversion unit 130 that converts the rotational motion of the 120 into a linear motion and transmits it to the hydraulic pressure providing unit 110 . Alternatively, the hydraulic pressure providing unit 110 may operate by the pressure provided from the high-pressure accumulator instead of the driving force supplied from the motor 120 .

Next, the flow paths 211, 212, 213, 214, 215, 216, 217 and the valves 231, 232, 233, 234, which are connected to the first pressure chamber 112 and the second pressure chamber 113, 235, 236, 241, 242, 243) will be described.

The second hydraulic oil passage 212 may communicate with the first hydraulic circuit 201 , and the third hydraulic oil passage 213 may communicate with the second hydraulic circuit 202 . Accordingly, hydraulic pressure may be transmitted to the first hydraulic circuit 201 and the second hydraulic circuit 202 by the advance of the hydraulic piston 114 .

In addition, the electromagnetic brake system 1 according to the embodiment of the present invention is provided in the second and third hydraulic oil passages 212 and 213, respectively, to control the flow of oil. A first control valve 231 and a second control valve ( 232) may be included.

And the first and second control valves 231 and 232 allow only the oil flow in the direction from the first pressure chamber 112 to the first or second hydraulic circuit 201 or 202, and the oil flow in the opposite direction. may be provided as a check valve to shut off. That is, the first or second control valves 231 and 232 allow the hydraulic pressure of the first pressure chamber 112 to be transmitted to the first or second hydraulic circuits 201 and 202 while allowing the first or second hydraulic pressure to be transferred. It is possible to prevent the hydraulic pressure of the circuits 201 and 202 from leaking into the first pressure chamber 112 through the second or third hydraulic passages 212 and 213 .

On the other hand, the fourth hydraulic oil passage 213 may be branched into a fifth hydraulic oil passage 215 and a sixth hydraulic oil passage 216 on the way to communicate with both the first hydraulic circuit 201 and the second hydraulic circuit 202 . . For example, the fifth hydraulic oil passage 215 branching from the fourth hydraulic oil passage 214 communicates with the first hydraulic circuit 201 , and the sixth hydraulic oil passage 216 branching from the fourth hydraulic oil passage 214 is It may communicate with the second hydraulic circuit 202 . Accordingly, hydraulic pressure may be transmitted to both the first hydraulic circuit 201 and the second hydraulic circuit 202 by the backward movement of the hydraulic piston 114 .

In addition, the electromagnetic brake system 1 according to the embodiment of the present invention is provided in the fifth hydraulic flow path 215 and provided in the third control valve 233 and the sixth hydraulic flow path 216 for controlling the flow of oil. It may include a fourth control valve 234 for controlling the flow.

The third control valve 233 may be provided as a bidirectional control valve for controlling the oil flow between the second pressure chamber 113 and the first hydraulic circuit 201 . In addition, the third control valve 233 may be provided as a normally closed solenoid valve that is normally closed and operates to open when an open signal is received from the electronic control unit.

And the fourth control valve 234 may be provided as a check valve that allows only the oil flow in the direction from the second pressure chamber 113 to the second hydraulic circuit 202, and blocks the oil flow in the opposite direction. . That is, the fourth control valve 234 prevents the hydraulic pressure of the second hydraulic circuit 202 from leaking to the second pressure chamber 113 through the sixth hydraulic passage 216 and the fourth hydraulic passage 214 . can

In addition, the electromagnetic brake system 1 according to the embodiment of the present invention is provided in the seventh hydraulic oil passage 217 connecting the second hydraulic oil passage 212 and the third hydraulic oil passage 213 to control the flow of oil. A fifth control valve 235 and a sixth control valve 236 provided in the eighth hydraulic oil passage 218 connecting the second hydraulic oil passage 212 and the seventh hydraulic oil passage 217 to control the flow of oil is included. can do. And the 5th control valve 235 and the 6th control valve 236 are normally closed solenoid valves of a normally closed type that operate to open when an open signal is received from the electronic control unit 2000. can be provided.

When an abnormality occurs in the first control valve 231 or the second control valve 232 , the fifth control valve 235 and the sixth control valve 236 operate to open the first pressure chamber 112 . The hydraulic pressure may be transmitted to both the first hydraulic circuit 201 and the second hydraulic circuit 202 .

In addition, the fifth control valve 235 and the sixth control valve 236 may operate to open when the hydraulic pressure of the wheel cylinder 40 is taken out and sent to the first pressure chamber 112 . This is because the first control valve 231 and the second control valve 232 provided in the second hydraulic passage 212 and the third hydraulic passage 213 are provided as check valves allowing only one-way oil flow.

In addition, the electromagnetic brake system 1 according to the embodiment of the present invention is provided in the first and second dump flow passages 116 and 117, respectively, and a first dump valve 241 and a second dump valve 241 and second dump valves ( 242) may be further included. The dump valves 241 and 242 may be check valves that open only a direction from the reservoir 30 to the first or second pressure chambers 112 and 113 and close in the opposite direction. That is, the first dump valve 241 allows oil to flow from the reservoir 30 to the first pressure chamber 112 , but blocks the flow of oil from the first pressure chamber 112 to the reservoir 30 . It may be a check valve, and the second dump valve 242 allows oil to flow from the reservoir 30 to the second pressure chamber 113 , but the oil flows from the second pressure chamber 113 to the reservoir 30 . The flow may be a shut-off check valve.

In addition, the second dump flow path 117 may include a bypass flow path, and the bypass flow path includes a third dump valve 243 for controlling the oil flow between the second pressure chamber 113 and the reservoir 30 . can be installed.

The third dump valve 243 may be provided as a solenoid valve capable of controlling the flow in both directions, and is opened in a normal state and operates to close the valve when a closing signal is received from the electronic control unit (Normal Open). type) solenoid valve.

The hydraulic pressure providing unit 110 of the electromagnetic brake system 1 according to the embodiment of the present invention may operate in a double acting type. That is, the hydraulic pressure generated in the first pressure chamber 112 while the hydraulic piston 114 moves forward is transmitted to the first hydraulic circuit 201 through the first hydraulic oil passage 211 and the second hydraulic oil passage 212 to the right side. The wheel cylinder 40 installed on the front wheel FR and the left rear wheel LR can act, and it is transmitted to the second hydraulic circuit 202 through the first hydraulic oil passage 211 and the third hydraulic oil passage 213 . and the wheel cylinder 40 installed on the right rear wheel RR and the left front wheel FL can act.

Similarly, the hydraulic pressure generated in the second pressure chamber 113 as the hydraulic piston 114 moves backward is transmitted to the first hydraulic circuit 201 through the fourth hydraulic flow path 214 and the fifth hydraulic flow path 215 to the right side. The wheel cylinder 40 installed on the front wheel FR and the left rear wheel LR can act, and it is transmitted to the second hydraulic circuit 202 through the fourth hydraulic oil passage 214 and the sixth hydraulic oil passage 216 . and the wheel cylinder 40 installed on the right rear wheel RR and the left front wheel FL can act.

In addition, the negative pressure generated in the first pressure chamber 112 while the hydraulic piston 114 is retracted sucks the oil of the wheel cylinder 40 installed in the right front wheel FR and the left rear wheel LR, and the first hydraulic circuit 201 , the second hydraulic passage 212 , and the first hydraulic passage 211 through the first pressure chamber 112 , and the wheels installed on the right rear wheel RR and the left front wheel FL The oil in the cylinder 40 may be sucked and transferred to the first pressure chamber 112 through the second hydraulic circuit 202 , the third hydraulic passage 213 , and the first hydraulic passage 211 .

Next, the motor 120 and the power conversion unit 130 of the hydraulic pressure supply device 100 will be described.

The motor 120 is a device for generating a rotational force according to a signal output from the electronic control unit 2000 , and may generate a rotational force in a forward or reverse direction. The rotation angular speed and rotation angle of the motor 120 may be precisely controlled. Since the motor 120 is a well-known technology, a detailed description thereof will be omitted.

On the other hand, the electronic control unit includes the motor 120 and the valves 54, 60, 221a, 221b, 221c, 221d, 222a, 222b, 222c, 222d, 233, 235, 236, 243). An operation in which the 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 generates displacement of the hydraulic piston 114 through the power conversion unit 130, and the hydraulic pressure generated while the hydraulic piston 114 slides within the pressure chamber is transferred to the first and second hydraulic flow paths. It is transmitted to the wheel cylinder 40 installed in each wheel (RR, RL, FR, FL) through (211, 212).

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

The worm shaft 131 may be integrally formed with the rotation shaft of the motor 120 , and a worm is formed on the outer circumferential surface to engage the worm wheel 132 to rotate the worm wheel 132 . The worm wheel 132 is connected to engage the drive shaft 133 to linearly move the drive shaft 133 , and the drive shaft 133 is connected to the hydraulic piston 114 to slide the hydraulic piston 114 in the cylinder block 111 . move it

When the above operations are described again, a signal sensed by the pedal displacement sensor 11 is transmitted to the electronic control unit 2000 while displacement occurs in the brake pedal 10 , and the electronic control unit operates the motor 120 in one direction. to rotate the worm shaft 131 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 114 connected to the drive shaft 133 moves forward to generate hydraulic pressure in the first pressure chamber 112 .

Conversely, when the pedal force is removed from the brake pedal 10 , the electronic control unit drives the motor 120 in the opposite direction to rotate the worm shaft 131 in the opposite direction. Accordingly, the worm wheel 132 also rotates in the opposite direction and the hydraulic piston 114 connected to the drive shaft 133 returns (moves backward) to generate negative pressure in the first pressure chamber 112 .

On the other hand, the generation of hydraulic pressure and negative pressure is also possible in the direction opposite to the above. That is, while displacement occurs in the brake pedal 10 , the signal sensed by the pedal displacement sensor 11 is transmitted to an electronic control unit (ECU, not shown), and the electronic control unit drives the motor 120 in the opposite direction. to rotate the worm shaft 131 in the opposite 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 114 connected to the drive shaft 133 moves backward to generate hydraulic pressure in the second pressure chamber 113 .

Conversely, when the pedal force is removed from the brake pedal 10 , the electronic control unit drives the motor 120 in one direction to rotate the worm shaft 131 in one direction. Accordingly, the worm wheel 132 also rotates in the opposite direction and the hydraulic piston 114 connected to the drive shaft 133 returns (moves forward) to generate a negative pressure in the second pressure chamber 113 .

As such, the hydraulic pressure supply device 100 serves to transmit the hydraulic pressure to the wheel cylinder 40 or suck the hydraulic pressure to the reservoir 30 according to the rotational direction of the rotational force generated from the motor 120 .

On the other hand, when the motor 120 rotates in one direction, hydraulic pressure may be generated in the first pressure chamber 112 or negative pressure may be generated in the second pressure chamber 113 . Whether to brake using hydraulic pressure, or negative pressure Whether to release the brake by using the valves 54 , 60 , 221a , 221b , 221c , 221d , 222a , 222b , 222c , 222d , 233 , 235 , 236 , 243 may be determined by controlling the valves. This will be described in detail later.

Although not shown in the drawings, the power conversion unit 130 may be configured as a ball screw nut assembly. For example, it consists of a screw formed integrally with the rotation shaft of the motor 120 or connected to rotate with the rotation shaft of the motor 120, and a ball nut that is screwed with the screw in a state of limited rotation and moves linearly according to the rotation of the screw. can be The hydraulic piston 114 is connected to the ball nut of the power conversion unit 130 to pressurize the pressure chamber by the linear motion of the ball nut. Since the structure of such a ball screw nut assembly is a well-known technique as a device for converting a rotational motion into a linear motion, a detailed description thereof will be omitted.

And it should be understood that the power conversion unit 130 according to the embodiment of the present invention can be employed in any structure as long as it can convert rotational motion into linear motion other than the structure of the ball screw nut assembly.

In addition, the electronic brake system 1 according to the embodiment of the present invention is a system capable of directly supplying the oil discharged from the master cylinder 20 to the wheel cylinders 40 when operating abnormally (fallback mode). The first and second backup passages 251 and 252 may be further included.

A first cut valve 261 for controlling the flow of oil may be provided in the first backup passage 251 , and a second cut valve 262 for controlling the flow of oil may be provided in the second backup passage 252 . have. In addition, the first backup passage 251 connects the first hydraulic port 24a and the first hydraulic circuit 201, and the second backup passage 252 is connected to the second hydraulic port 24b and the second hydraulic circuit ( 202) can be connected.

In addition, the first and second cut valves 261 and 262 may be provided as a solenoid valve of a normal open type that is opened in a normal state and operates to close the valve when a closing signal is received from the electronic control unit. have.

Next, the hydraulic control unit 200 according to the embodiment of the present invention will be described with reference to FIG. 1 .

The hydraulic control unit 200 may include a first hydraulic circuit 201 and a second hydraulic circuit 202 that receive hydraulic pressure to control two wheels, respectively. For example, the first hydraulic circuit 201 may control the right front wheel FR and the left rear wheel RL, and the second hydraulic circuit 202 may control the left front wheel FL and the right rear wheel RR. . In addition, a wheel cylinder 40 is installed on each of the wheels FR, FL, RR, and RL to receive hydraulic pressure to perform braking.

The first hydraulic circuit 201 is connected to the first hydraulic passage 211 and the second hydraulic passage 212 to receive hydraulic pressure from the hydraulic pressure supply device 100 , and the second hydraulic passage 212 is connected to the right front wheel FR ) and the left rear wheel (RL). Similarly, the second hydraulic circuit 202 is connected to the first hydraulic passage 211 and the third hydraulic passage 213 to receive hydraulic pressure from the hydraulic pressure supply device 100 , and the third hydraulic passage 213 is the left front wheel. It branches into two flow paths connected to (FL) and the right rear wheel (RR).

The hydraulic circuits 201 and 202 may include a plurality of inlet valves 221 (221a, 221b, 221c, 221d) to control the flow of hydraulic pressure. For example, the first hydraulic circuit 201 may be provided with two inlet valves 221a and 221b connected to the first hydraulic flow path 211 to respectively control the hydraulic pressure transmitted to the two wheel cylinders 40 . . In addition, the second hydraulic circuit 202 may be provided with two inlet valves 221c and 221d that are connected to the second hydraulic flow path 212 to respectively control the hydraulic pressure transmitted to the wheel cylinder 40 .

In addition, the inlet valve 221 is disposed on the upstream side of the wheel cylinder 40, is open in a normal state, and is a normally open type solenoid valve that operates to close the valve when a closing signal is received from the electronic control unit. can be provided with

In addition, the hydraulic circuits 201 and 202 may include check valves 223a, 223b, 223c, 223d provided in the bypass flow path connecting the front and rear of each of the inlet valves 221a, 221b, 221c, and 221d. can The check valves 223a, 223b, 223c, and 223d allow only the flow of oil from the wheel cylinder 40 to the hydraulic pressure providing unit 110 in the direction, and from the hydraulic pressure providing unit 110 to the wheel cylinder 40 direction. The flow of may be provided to limit. The check valves 223a, 223b, 223c, and 223d can quickly release the braking pressure of the wheel cylinder 40, and when the inlet valves 221a, 221b, 221c, and 221d do not operate normally, the wheel cylinder The hydraulic pressure of ( 40 ) may be introduced into the hydraulic pressure providing unit ( 110 ).

In addition, the hydraulic circuits 201 and 202 may further include a plurality of outlet valves 222 (222a, 222b, 222c, 222d) connected to the reservoir 30 to improve performance when braking is released. The outlet valves 222 are respectively connected to the wheel cylinders 40 to control the hydraulic pressure to escape from the respective wheels RR, RL, FR, and FL. That is, the outlet valve 222 detects the braking pressure of each wheel RR, RL, FR, and FL, and is selectively opened when pressure reduction braking is required to control the pressure.

In addition, the outlet valve 222 may be provided as a normally closed solenoid valve that is normally closed and operates to open the valve when an open signal is received from the electronic control unit.

In addition, the hydraulic control unit 200 may be connected to the backup flow passages 251 and 252 . For example, the first hydraulic circuit 201 is connected to the first backup passage 251 to receive hydraulic pressure from the master cylinder 20 , and the second hydraulic circuit 202 is connected to the second backup passage 252 , Hydraulic pressure may be provided from the master cylinder 20 .

At this time, the first backup flow path 251 may join the first hydraulic circuit 201 upstream of the first and second inlet valves 221a and 221b. Similarly, the second backup flow path 252 may join the second hydraulic circuit 202 upstream of the third and fourth inlet valves 221c and 221d. Therefore, when the first and second cut valves 261 and 262 are closed, the hydraulic pressure provided from the hydraulic pressure supply device 100 is supplied to the wheel cylinder 40 through the first and second hydraulic circuits 201 and 202. When the first and second cut valves 261 and 262 are opened, the hydraulic pressure provided from the master cylinder 20 is supplied to the wheel cylinder 40 through the first and second backup passages 251 and 252. can At this time, since the plurality of inlet valves 221a, 221b, 221c, and 221d are in an open state, it is not necessary to change the operating state.

On the other hand, the unexplained reference numeral "PS11" is a first hydraulic oil pressure sensor for detecting the hydraulic pressure of the first hydraulic circuit 201, and "PS12" is a second hydraulic oil for detecting the hydraulic pressure of the second hydraulic circuit 202 . It is a low pressure sensor, and "PS2" is a backup flow path pressure sensor that measures the oil pressure of the master cylinder 20 . And “MPS” is a motor control sensor that controls 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.

The hydraulic pressure supply device 100 may be used in a low pressure mode and a high pressure mode separately. The low pressure mode and the high pressure mode may be changed by different operations of the hydraulic control unit 200 . The hydraulic pressure supply device 100 may generate a high hydraulic pressure without increasing the output of the motor 120 by using the high pressure mode. Therefore, it is possible to guarantee stable braking power while lowering the price and weight of the brake system.

In more detail, the hydraulic piston 114 generates hydraulic pressure in the first pressure chamber 112 while advancing. As the hydraulic piston 114 advances from the initial state, that is, as the stroke of the hydraulic piston 114 increases, the amount of oil transferred from the first pressure chamber 112 to the wheel cylinder 40 increases and the braking pressure decreases. rises However, since there is an effective stroke of the hydraulic piston 114 there is a maximum pressure due to the advance of the hydraulic piston 114 .

At this time, the maximum pressure in the low pressure mode is smaller than the maximum pressure in the high pressure mode. However, in the high pressure mode, the pressure increase rate per stroke of the hydraulic piston 114 is small compared to the low pressure mode. This is because, not all of the oil pushed out from the first pressure chamber 112 flows into the wheel cylinder 40 , but a part flows into the second pressure chamber 113 . This will be described in detail with reference to FIG. 5 .

Therefore, the low-pressure mode with a large pressure increase rate per stroke can be used in the early stage of braking when braking response is important, and the high-pressure mode with a large return pressure can be used in the late stage of braking when the maximum braking force is important.

When braking by the driver is started, the amount of braking required by the driver may be detected through information such as the pressure of the brake pedal 10 that the driver steps through the pedal displacement sensor 11 . The electronic control unit 2000 receives the electrical signal output from the pedal displacement sensor 11 to drive the motor 120 .

In addition, the electronic control unit receives the input of the amount of regenerative braking through the backup flow path pressure sensor PS2 provided on the outlet side of the master cylinder 20 and the hydraulic flow path pressure sensor PS1 provided on the second hydraulic circuit 202. , the magnitude of the friction braking amount may be calculated according to the difference between the driver's required braking amount and the regenerative braking amount to determine the pressure increase or pressure reduction of the wheel cylinder 40 .

2 and 3 show a state in which the ABS is operated in the electronic brake system 1 according to an embodiment of the present invention. FIG. 2 shows a situation in which the hydraulic piston 114 selectively brakes while moving forward, It is a hydraulic circuit diagram showing a situation in which the hydraulic piston 114 selectively brakes while moving backward.

When the motor 120 operates according to the pedaling force of the brake pedal 10 , the rotational force of the motor 120 is transmitted to the hydraulic pressure providing unit 110 through the power transmitting unit 130 to generate hydraulic pressure. At this time, the first and 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 .

Referring to FIG. 2 , the hydraulic piston 114 moves forward to generate hydraulic pressure in the first pressure chamber 112 , and the fourth inlet valve 221d is provided in an open state to provide the first hydraulic oil passage 211 and the third hydraulic oil. Hydraulic pressure transmitted through the furnace 213 operates the wheel cylinder 40 located on the left front wheel FL to generate braking force.

At this time, the first to third inlet valves 221a, 221b, and 221c are switched to a closed state, and the first to fourth outlet valves 222a, 222b, 222c, and 222d remain closed. And the third dump valve 243 is provided in an open state to fill the second pressure chamber 113 with oil from the reservoir 30 .

Referring to FIG. 3 , the hydraulic piston 114 moves backward to generate hydraulic pressure in the second pressure chamber 113 , and the first inlet valve 221a is opened to provide a fourth hydraulic flow path 214 and a second hydraulic oil. Hydraulic pressure transmitted through the furnace 212 operates the wheel cylinder 40 located on the right front wheel FR to generate braking force.

At this time, the second to fourth inlet valves 221b, 221c, and 221d are switched to a closed state, and the first to fourth outlet valves 222a, 222b, 222c, and 222d remain closed.

That is, the electronic brake system 1 according to the embodiment of the present invention includes a motor 120 and each of the valves 54, 60, 221a, 221b, 221c, 221d, 222a, 222b, 222c, 222d, 233, 235, By independently controlling the operations of 236 and 243, hydraulic pressure can be selectively transmitted or discharged to the wheel cylinder 40 of each wheel (RL, RR, FL, FR) according to the required pressure, enabling precise pressure control do.

Next, FIG. 4 is an internal block diagram of the electronic brake system 1 according to an embodiment of the present invention, and the electronic control unit 2000 and the electronic brake system 1 that collectively control the electronic brake system 1 ) is a block diagram showing a state connected to the brake device 1000 included in the ), and FIG. 5 is a detailed block diagram.

Referring to FIG. 5 , the electronic control unit 2000 of the electronic brake system 1 according to an embodiment of the present invention includes an input unit 102 , a determination unit 104 , and a calculation unit 106 and a control unit 108 . include

The input unit 102 receives operation signals from the motor position sensor 121 , the brake pedal 10 , the motor 120 , the piston 114 , the pressure sensor ps1 , and the inlet valve 221 of the brake device 1000 . receive input

Here, the brake device 1000 may be an IDB (Integrated Dynamic Brake) that generates a boosting pressure and a braking pressure with a single motor 121 , and may be any brake means that generates a braking pressure with a motor. That is, the electronic brake system 1 shown in FIG. 1 may correspond to this.

Although not shown, the motor 121 may be a permanent magnet synchronous motor (not shown), and the permanent magnet synchronous motor (not shown) includes an embedded permanent magnet synchronous motor (not shown) and a surface mounted permanent magnet synchronous motor. (not shown) may be at least one.

The determination unit 104 determines whether the leakage failure state in the electronic brake system 1 is based on the motor position sensed value input to the input unit 102 under the control of the control unit 108 to be stated later.

The calculation unit 106 calculates the movement distance of the piston based on the motor position sensor value obtained from the input unit 102 . In addition, the calculator 106 calculates the pump discharge flow rate based on the movement distance of the piston and the cross-sectional area information of the pump of the electromagnetic brake system 1 . That is, the pump discharge flow rate may be calculated as the product of the moving distance of the piston and the cross-sectional area of the pump.

In addition, the calculator 106 estimates the flow rate flowing into the cylinder 40 of each wheel (FR, FL, RR, RL). That is, when fluid flows into the wheel cylinder through the wheel inlet valve 221, the flow rate flowing into the wheel cylinder is estimated. The circuit pressure value obtained by the input unit 102 from the pressure sensor PS, and the inlet valve ( 221) can be used to estimate the flow rate.

Specifically, the flow rate flowing into the wheel cylinder can be calculated by [Equation 1].

[Equation 1]

In this case, V denotes the flow rate flowing into the wheel cylinder, C _d denotes the amount of current of the inlet valve, A _orifice denotes the cross-sectional area, ρ denotes a constant, and P supply denotes the pump hydraulic pressure calculated by the calculator 106 . and P wheel means the circuit pressure flowing into the wheel cylinder.

Accordingly, the calculator 106 may estimate the flow rate flowing into the wheel cylinder based on [Equation 1].

Next, as shown in FIGS. 2 and 3 , the controller 108 controls the ratio of the flow rate discharged from the pump to the estimated flow rate flowing into the wheel cylinder through the inlet valve when the electronic brake system 1 is in the ABS operation. is calculated and compared with a preset threshold value, and when the threshold value is exceeded, it is determined that a leak has occurred.

Thereafter, when the determination unit 104 determines that the leakage has occurred under the control of the control unit 108 , the determination unit 104 acquires the slip amount of each wheel in order to determine which wheel of the at least one wheel has the leakage.

Specifically, when the input unit 102 obtains a value for detecting the slip of each wheel, the determination unit 104 determines whether the wheel slip is continuously maintained within a preset threshold value (second threshold value). to be judged as

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

Hereinafter, a method of controlling the electronic brake system 1 according to the present invention will be described. Specifically, FIG. 6 is a flowchart illustrating a control method of the electronic brake system 1 according to an exemplary embodiment.

First, the electronic brake system 1 calculates the flow rate V1 discharged from the piston based on the motor position sensor value (600, 610, 620). That is, the calculation unit 106 in the electronic brake system 1 calculates the movement distance of the piston based on the motor position sensor value obtained from the input unit 102 (610), and calculates the pump discharge flow rate (v1). have.

Also, the electronic brake system 1 obtains a pressure sensor value from a plurality of pressure sensors PS included in the brake device 1000 and obtains an amount of valve current that drives the inlet valve 221 of the wheel ( 640 ). . Thereafter, the electronic brake system 1 estimates the flow rate v2 flowing into the wheel cylinders based on the above-mentioned [Equation 1].

However, steps 600 , 610 and 630 in the electronic brake system 1 may be performed in parallel.

Thereafter, the control unit of the electronic brake system 1 compares the flow rate discharged from the piston with the flow rate flowing into the wheel cylinder. Specifically, the control unit 108 may perform a comparison with a ratio value set as the first threshold value in the electronic brake system 1 set in advance ( 660 ). Therefore, if the ratio of the flow rate discharged from the piston and the flow rate flowing into the wheel cylinder, which can be expressed as (V1/V2), is greater than the first threshold value, it is determined that the leak occurs during ABS progress ( 670 ).

Accordingly, the control unit 108 additionally monitors the slip amounts of FR, FL, RR, and RL in order to determine which wheel of each wheel has a leak ( 680 ).

For example, as shown in 690 of FIG. 6 , in the case where the first slip occurs in at least one of FR, Fl, RR, and Rl, if the first slip is maintained less than a preset second threshold, (Yes in 690), it is determined as a leak of the wheel in which the first slip has occurred (700)

In the above, one embodiment of the disclosed invention has been illustrated and described, but the disclosed invention is not limited to the specific embodiments described above, and those of ordinary skill in the art to which the disclosed invention belongs without departing from the gist of the claims Various modifications are possible, of course, and these modifications cannot be individually understood from the disclosed invention.

10: brake pedal 11: pedal displacement sensor
20: master cylinder 30: reservoir
40: wheel cylinder 50: simulation device
54: simulator valve 60: inspection valve
100: hydraulic pressure supply unit 110: hydraulic pressure supply unit
120: motor 130: power conversion unit
200: hydraulic control unit 201: first hydraulic circuit
202: second hydraulic circuit 211: first hydraulic flow path
212: second hydraulic flow path 213: third hydraulic flow path
214: fourth hydraulic flow path 215: fifth hydraulic flow path
216: 6th hydraulic flow path 217: 7th hydraulic flow path
218: eighth hydraulic flow path 221: inlet valve
222: outlet valve 223: check valve
231: first control valve 232: second control valve
233: third control valve 234: fourth control valve
235: fifth control valve 236: sixth control valve
241: first dump valve 242: second dump valve
243: third dump valve 251: first backup flow path
252: second backup flow path 261: first cut valve
262: second cut valve

Claims (8)

a master cylinder that discharges oil according to the pedal effort;
a reservoir connected to the master cylinder and storing oil;
a hydraulic pressure supply device for generating hydraulic pressure using a rotational force of a motor operated by an electrical signal output from the pedal position sensor;
a first hydraulic circuit for transferring the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided on at least one wheel; and
In the electromagnetic brake system comprising a; a second hydraulic circuit for transmitting the hydraulic pressure discharged from the hydraulic pressure supply device to the wheel cylinder provided on at least one or more wheels,
a motor position sensor that measures the position of the motor;
a first pressure sensor for measuring hydraulic pressure; and
estimating the flow rate discharged from the piston based on the motor position sensor value, estimating the flow rate flowing into the wheel based on the measured hydraulic pressure, and comparing the flow rate discharged from the piston with the flow rate flowing into the wheel. The electronic brake system further comprising a; a control unit for determining whether a leak occurs in the electronic brake system. According to claim 1,
When the ratio of the flow rate discharged from the piston to the flow rate flowing into the wheel is greater than a first threshold value, the electronic brake system determines that the electronic brake system is leaking. 3. The method of claim 2,
The control unit may determine that a leak has occurred in the electronic brake system, and if the slip value of the at least one or more wheels is less than a preset threshold value, the electronic brake system determines that the leak has occurred in the wheel. 4. The method of claim 3,
The first hydraulic circuit further includes at least one inlet valve for adjusting the flow rate discharged from the hydraulic pressure supply device,
The second hydraulic circuit may further include at least one inlet valve for controlling a flow rate discharged from the hydraulic pressure supply device. 5. The method of claim 4,
The control unit may be configured to determine a flow rate flowing into the wheel based on a current of the inlet valve and the measured hydraulic pressure. a master cylinder that discharges oil according to the pedal effort;
a reservoir connected to the master cylinder and storing oil;
a hydraulic pressure supply device for generating hydraulic pressure using a rotational force of a motor operated by an electrical signal output from the pedal position sensor;
a first hydraulic circuit for transferring the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided on at least one wheel; and
In the electromagnetic brake system comprising a; a second hydraulic circuit for transmitting the hydraulic pressure discharged from the hydraulic pressure supply device to the wheel cylinder provided on at least one or more wheels,
A motor position sensor measuring the position of the motor;
a pressure sensor measuring hydraulic pressure; and
estimating the flow rate discharged from the piston based on the motor position sensor value, estimating the flow rate flowing into the wheel based on the measured hydraulic pressure, and comparing the flow rate discharged from the piston with the flow rate flowing into the wheel. A control method of an electronic brake system including a; determining whether a leak occurs in the electronic brake system. 7. The method of claim 6,
When the ratio of the flow rate discharged from the piston to the flow rate flowing into the wheel is greater than a first threshold value, determining the leakage of the electronic brake system; 8. The method of claim 7,
and determining that a leak has occurred in the electronic brake system, and when the slip value of the at least one or more wheels is smaller than a preset threshold value, determining the leak in the wheel.

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