KR20190061252A - Electric brake system and Control method thereof - Google Patents

Abstract

Disclosed is an electronic brake system. According to an embodiment of the present invention, the electronic brake system comprises: a master cylinder connected to a reservoir storing an oil and provided with a master chamber and a master piston arranged in the master chamber to discharge oil according to the force of a brake pedal; a pedal simulator providing a reaction force depending on the force of the brake pedal and connected to the master cylinder to have a simulator chamber accommodating the oil; a hydraulic control unit controlling the flow of a liquid pressure transmitted between the master cylinder and a wheel cylinder; a liquid pressure supply device actuated by an electric signal outputted corresponding to a displacement of the brake pedal to supply a liquid pressure to the hydraulic control unit; and a pressure boosting device boosting the liquid pressure transmitted from the master cylinder to the hydraulic control unit when the liquid supply device is abnormally operated. The present invention can provide a braking pressure to the wheel cylinder during an emergency.

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 a control method thereof, and more particularly, to an electronic brake system that generates a braking force by an electrical signal 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.

An electronic brake system equipped with such a hydraulic pressure supply device is disclosed in European Patent EP 2 520 473. According to the disclosed document, the hydraulic pressure supply device is configured to operate the motor in accordance with the power of the brake pedal to generate the braking pressure. At this time, the braking pressure is generated by converting the rotational force of the motor into a linear motion and pressing the piston.

On the other hand, in the conventional electronic brake system, when the hydraulic pressure supply device does not operate normally, a fall-back mode in which the hydraulic pressure of the master cylinder is directly transmitted to the wheel cylinder is operated, thereby assuring emergency braking. However, when the driver provides the same brake pedal depression force, there is a problem that the braking force in the fallback mode is smaller than the braking force when the hydraulic pressure supply apparatus normally operates, and more time is required to form the pressure.

In addition, when the hydraulic pressure supply device does not operate normally when the driver does not have a pedal input, such as ACC (Adaptive Cruse Control), TJA (Traffic Jam Assist), or AEB (Autonomous Emergency Braking) .

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

An embodiment of the present invention is to provide an electronic brake system capable of providing braking pressure to a wheel cylinder in an emergency.

According to an aspect of the present invention, there is provided a master cylinder comprising: a master cylinder connected to a reservoir for storing oil and having a master chamber and a master piston provided in the master chamber to discharge oil according to the pressure of the brake pedal; A pedal simulator for providing a reaction force in response to the power of the brake pedal, the pedal simulator being connected to the master cylinder and having a simulator chamber in which oil is received; A hydraulic control unit for controlling the flow of hydraulic pressure transmitted between the master cylinder and the wheel cylinder; A hydraulic pressure supply device that operates by an electrical signal outputted in response to displacement of the brake pedal to supply hydraulic pressure to the hydraulic control unit; And a boosting device for boosting a hydraulic pressure transmitted from the master cylinder to the hydraulic control unit when the hydraulic pressure supply device is operating abnormally.

The booster may be provided in a reservoir passage connecting the reservoir and the master cylinder.

The master cylinder further includes a first master piston directly pressurized by the brake pedal, a first master chamber in which the first master piston is accommodated, a second master piston, which is indirectly biased by the first master piston, And a second master chamber in which the second master piston is received, wherein the hydraulic control unit includes a first hydraulic circuit and a second hydraulic circuit for supplying hydraulic pressure to at least one wheel cylinder, The chamber communicates with the reservoir through a first reservoir passage and is connected to the first hydraulic circuit through a first backup channel. The second master chamber communicates with the reservoir through a second reservoir channel. And the booster may be provided in the second reservoir flow passage.

In addition, when the hydraulic pressure supply device operates abnormally, the hydraulic pressure of the first master chamber is transmitted to the first hydraulic circuit, and the hydraulic pressure of the second master chamber is added to the hydraulic pressure of the second master chamber, Can be delivered to the hydraulic circuit.

The first hydraulic circuit may include a wheel cylinder provided in either the front wheel or the rear wheel, and the second hydraulic circuit may include a wheel cylinder provided in the other of the front wheel and the rear wheel.

In addition, when the hydraulic pressure supply device operates abnormally and the driver provides the brake pedal with pressure, the hydraulic pressure provided by the pressure-increasing device is added to the hydraulic pressure of the master cylinder by the driver's power, .

In addition, when the hydraulic pressure supply device operates abnormally and the driver does not provide the brake pedal with pressure, the hydraulic pressure provided by the pressure increasing device can be transmitted to the wheel cylinder through the master cylinder.

The booster may include a pump unit provided in a second reservoir flow passage and a first booster valve provided in a third reservoir flow passage bypassing the second reservoir flow passage.

The booster further includes a second booster valve provided in a fourth reservoir passage bypassing the second and third reservoir flow paths. The first booster valve is provided with a bidirectional valve for controlling the flow in both directions And the second pressure-rising valve may be provided as a one-way valve that allows only the flow from the reservoir to the master cylinder.

The booster may further include a pressure sensor provided at a rear end of the reservoir flow path in which the second to fourth reservoir flow paths are merged.

The first reservoir passage is provided with a one-way valve which allows only the flow from the reservoir to the master cylinder, and a check valve which is provided in a bypass passage bypassing the first reservoir passage, And the booster may include a pump unit provided in the second reservoir flow passage and a booster valve provided in a third reservoir flow passage bypassing the second reservoir flow passage.

According to another embodiment of the present invention, there is provided a method of controlling the electronic brake system, comprising: determining whether the hydraulic pressure supply device is in a normal state; and operating the hydraulic pressure supply device A control method of an electronic brake system for generating a braking pressure of the wheel cylinder and generating the braking pressure of the wheel cylinder by operating the boosting device when the hydraulic pressure supply device is determined to be in an abnormal state can be provided.

Embodiments of the present invention seek to provide a desired braking pressure to a wheel cylinder using a boost device when the brake system that provides braking pressure is operating abnormally using a hydraulic pressure supply.

For example, in the event of emergency, when the driver provides the brake pedal pressure, the hydraulic pressure of the master cylinder is stepped up and provided to the wheel cylinder to generate a sufficient braking pressure as compared with normal operation.

Further, it is possible to provide the braking pressure to the wheel cylinder by using the booster device even in the event of an emergency in which the braking pressure should be applied in the state in which the driver does not input the pedal.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a hydraulic circuit diagram showing a non-synchronized state of an electronic brake system according to an embodiment of the present invention; FIG.
2 is an enlarged view of a booster according to an embodiment of the present invention.
3 is a graph showing the hydraulic pressure generated by the pressure-rising device according to the embodiment of the present invention in the input state of the brake pedal.
4 is a graph showing the hydraulic pressure generated by the booster according to the embodiment of the present invention when the brake pedal is not being input.
5 is a flowchart showing conditions under which the booster device operates.

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.

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

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. For example, the master cylinder 20 may include a first master chamber 20a and a second master chamber 20b.

The first master chamber 20a is provided with a first piston 21a connected to the input rod 12 and the second master chamber 20b is provided with a second piston 22a. The first master chamber 20a communicates with the first hydraulic port 24a and the oil flows in and out. The second master chamber 20b communicates with the second hydraulic port 24b to allow the oil to flow in and out. For example, the first hydraulic port 24a may be connected to the first backup channel 251, and the second hydraulic port 24b may be coupled to the second backup channel 252.

On the other hand, the master cylinder 20 has two master chambers 20a and 20b to ensure safety in case of failure. The master chamber 20a of one of the two master chambers 20a and 20b is connected to the right front wheel FR and the left rear wheel RL of the vehicle through the first backup channel 251, The chamber 20b may be connected to the left front wheel FL and the right rear wheel RR through the second backup oil passage 252. [ In this way, by independently configuring the two master chambers 20a and 20b, it is possible to braking the vehicle even if one of the master chambers fails.

Alternatively, the master chamber of one of the two master chambers may be connected to the two front wheels FR and FL, and the other master chamber may be connected to the two rear wheels RR and RL, as shown in the figure.

The master chamber of one of the two master chambers may be connected to the left front wheel FL and the left rear wheel RL and the other master chamber may be connected to the right rear wheel RR and the right front wheel FR. That is, the positions of the wheels connected to the master chambers of the master cylinder 20 can be variously configured.

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. That is, the first piston 21b is accommodated in the first master chamber 20a, and the second piston 22b is accommodated in the second master chamber 20b.

The first spring 21b and the second spring 22b are compressed by the first piston 21a and the second piston 22a which move as the displacement of the brake pedal 10 changes. When the pushing force of the first piston 21a becomes smaller than the elastic force, the first and second pistons 21a and 22a are pushed back by using the restoring 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 first master chamber 20a is connected to the reservoir 30 through the first reservoir passage 61 and the second master chamber 20b is connected to the reservoir 30 through the second reservoir passage 62 .

The master cylinder 20 may include two sealing members disposed on the front and rear sides of the first reservoir passage 61 and two sealing members disposed on the front and rear sides of the second reservoir passage 62. [ The sealing member may be in the shape of a ring protruding from the inner wall of the master cylinder 20 or the outer peripheral surface of the pistons 21a and 22a.

The flow of the oil flowing into the reservoir 30 from the first master chamber 20a while allowing the flow of oil flowing from the reservoir 30 to the first master chamber 20a is allowed to flow into the first reservoir passage 61, A check valve 67 may be provided. The check valve 67 may be provided to allow only one directional fluid flow.

The front and rear of the check valve 67 of the first reservoir passage may be connected by a bypass passage 66. A check valve 60 may be provided in the bypass flow path 66.

The check valve 60 may be provided as a bidirectional control valve for controlling the flow of oil between the reservoir 30 and the master cylinder 20. The check valve 60 may be provided as a normally open type solenoid valve which is normally open and operates to close the valve when receiving a close signal from the electronic control unit.

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 front end of the simulation chamber 51. The simulator valve 54 is a pedal simulator.

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 first backup channel 251 and the simulation chamber 51. The front end of the simulation chamber 51 may be connected to the master cylinder 20 via the simulator valve 54 and the first backup flow path 251 and the rear end of the simulation chamber 51 may be connected to the reservoir 30.

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 oil in the simulation chamber 51 to the reservoir 30.

Further, when the reaction force piston 52 is returned while the simulator valve 54 is opened, the oil of the reservoir 30 may be introduced and the entire interior of the simulation chamber 51 may be filled with oil.

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 in the simulation chamber 51 to flow into the first master chamber 20a while the oil in the first master chamber 20a is simulated through the flow path in which the check valve 55 is installed. It is possible to shut off the flow to the chamber 51. Therefore, a quick return of the pedal simulator pressure can be ensured because the oil in the simulation chamber 51 can escape through the simulator check valve 55 when the brake pedal 10 is released.

The operation of the pedal simulation apparatus 50 will now be described. When the driver gives a pressing force to the brake pedal 10, the oil introduced through the open simulator valve 54 presses the reaction force piston 52 of the pedal simulator And the oil in the simulation chamber 51 pushing the reaction force piston 52 while compressing the reaction force spring 53 is transmitted to the reservoir 30. In this process, the driver is provided with a pedal feel.

On the contrary, when the driver releases his or her foot to the brake pedal 10, the reaction force piston 52 whose pressure has been released returns to its original position by the elastic force of the reaction force spring 53, The oil can be filled into the simulation chamber 51 while being introduced into the simulation chamber 51. The oil filled in the front end of the reaction force piston 52 in the simulation chamber 51 is returned to the master cylinder 20 through the flow path in which the simulator valve 54 is installed and the check valve 55 is installed .

As described above, since the inside of the simulation chamber 51 is always filled with oil in the braking state and the releasing state, the friction of the reaction force piston 52 is minimized during the operation of the simulation apparatus 50, so that the durability of the simulation apparatus 50 As well as the inflow of foreign matter from the outside 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, And an electronic control unit (ECU) (not shown) for controlling the supply device 100 and the valves.

The hydraulic pressure supply 100 provides the oil pressure delivered to the wheel cylinders 40. The hydraulic pressure supply device 100 may be variously provided. For example, a piston (not shown) driven by the driving force of a motor (not shown) may push the oil in the chamber and transmit the hydraulic pressure to the wheel cylinder 40. Alternatively, the hydraulic pressure supply device 100 may be provided in a motor-driven pump or a high-pressure accumulator.

More specifically, when the driver presses the brake pedal 10, an electric signal is transmitted from the pedal displacement sensor 11 as the displacement of the brake pedal 10 changes, and the motor operates by this signal. Between the motor and the piston, a power converting unit for converting a rotational motion of the motor into a linear motion may be provided. The power converting unit may include a worm, a worm gear, and / or a rack and pinion gear.

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 an inlet valve (not shown) provided at the front end of each wheel cylinder 40 for controlling the hydraulic pressure and an outlet valve 32 connected to the reservoir 30, And may include a valve (not shown).

Next, the connection relation between the reservoir 30 and the hydraulic circuit according to the embodiment of the present invention will be described.

The reservoir 30 according to an embodiment of the present invention may include three reservoir chambers 31, 32, 33. In one example, the three reservoir chambers 31, 32, 33 may be arranged side by side in a row.

Adjacent reservoir chambers 31, 32, 33 may be separated by a partition wall. For example, the first reservoir chamber 31 and the second reservoir chamber 33 may be divided into first partition walls, and the second reservoir chamber 33 and the third reservoir chamber 21 may be divided into second partition walls have.

The first and third reservoir chambers 31, 32, and 33 may communicate with each other. Accordingly, the pressures of the first to third reservoir chambers 31, 32, and 33 may be equal to each other. In one example, the pressures of the first to third reservoir chambers 31, 32, and 33 may be equal to atmospheric pressure.

The first reservoir chamber 31 may be connected to the first master chamber 20a of the master cylinder 20, the wheel cylinder 40, and the simulation apparatus 50. The first reservoir chamber 31 may be connected to the first master chamber 20a through the first reservoir passage 61. [ The first reservoir chamber 31 may be connected to two wheel cylinders of the four wheel cylinders 40, for example, a wheel cylinder 40 provided on the right front wheel FR and the left rear wheel RL.

The connection between the first reservoir chamber 31 and the first master chamber 20a can be controlled by the check valve 67 and the check valve 60 and the connection between the first reservoir chamber 31 and the simulation apparatus 50, The connection of the first reservoir chamber 31 and the wheel cylinder 40 can be controlled by the simulator valve 54 and the simulator check valve 55 via the outlet valve (not shown) provided in the hydraulic control unit 200 Not shown).

The second reservoir chamber 32 may be connected to the second master chamber 20b of the master cylinder 20 and the wheel cylinder 40. [ The second reservoir chamber 32 may be connected to the second master chamber 20b through the second reservoir 30 flow path 62. The second reservoir chamber 32 may be connected to the other two wheel cylinders of the four wheel cylinders 40, for example, the wheel cylinders 40 provided on the right rear wheel RR and the left front wheel FL.

And the connection of the second reservoir chamber 32 and the second master chamber 20b can be controlled by the first control valve 330 or the second control valve 340 shown in FIG. The connection between the wheel cylinder 32 and the wheel cylinder 40 can be controlled by an outlet valve (not shown) provided in the hydraulic control unit 200.

In addition, the third reservoir chamber 33 may be connected to the hydraulic pressure supply device 100. Or the third reservoir chamber 33 may be connected to various hydraulic pressure supply devices. As an example, it can be connected to a pump.

The reservoir 30 includes a third reservoir chamber 33 connected to the hydraulic pressure supply device 100 and first and second reservoir chambers 31 and 32 connected to the first and second master chambers 20a and 20b Can be separately provided. If the reservoir chamber for supplying oil to the hydraulic pressure supply device 100 and the reservoir chamber for supplying oil to the master chambers 20a and 20b are provided in the same manner, The reservoir 30 can not properly supply the oil to the master chambers 20a and 20b.

The reservoir 30 is provided separately from the third reservoir chamber 33 and the first and second reservoir chambers 31 and 32 so that the reservoir 30 Can normally supply oil to the first and second master chambers 20a and 20b so that emergency braking can be performed.

Likewise, the reservoir 30 may separately provide a first reservoir chamber 32 connected to the first master chamber 20a and a second reservoir chamber 32 connected to the second master chamber 20b. If the reservoir chamber for supplying the oil to the first master chamber 20a and the reservoir chamber for supplying the oil to the second master chamber 20b are provided in the same manner, the reservoir 30 is provided in the first master chamber 20a If the oil can not be properly supplied, the reservoir 30 can not supply oil to the second master chamber 20b properly.

The reservoir 30 is provided separately from the first reservoir chamber 31 and the third reservoir chamber 33 so that when the reservoir 30 fails to properly supply oil to the first master chamber 20a, The braking pressure can be formed on the two wheel cylinders 40 of the four wheel cylinders 40 by normally supplying the oil to the master chamber 20b.

The reservoir 30 separates an oil line (not shown) connected to the reservoir 30 from the hydraulic pressure supply device 100 and a dump line (not shown) connected to the reservoir 30 from the wheel cylinder 40 . Therefore, it is possible to prevent bubbles, which may occur in the dump line at the ABS braking, from flowing into the chamber of the hydraulic pressure supply device 100, thereby preventing the ABS performance from deteriorating.

Reference numeral " PS1 " is a hydraulic pressure sensor for sensing the hydraulic pressure of the hydraulic circuits 201 and 202, and PS2 is a backup hydraulic pressure sensor for measuring the oil pressure of the master cylinder 20. [

Next, the booster 300 according to the embodiment of the present invention will be described with reference to FIG. 2 to FIG.

2 is an enlarged view showing a booster 300 according to an embodiment of the present invention.

The booster 300 is provided to boost the hydraulic pressure generated in the master cylinder 20 in an emergency and to transmit the boosted hydraulic pressure to the wheel cylinder 40. Here, when the hydraulic pressure supply apparatus 100 is in an emergency state, it means that the hydraulic pressure supply apparatus 100 does not normally operate.

The cut valves 261 and 262 are switched to the closed state and the hydraulic pressure of the master cylinder 20 is not transmitted to the wheel cylinder 40 in the normal state when the driver supplies the brake pedal 10 with pressure, The hydraulic pressure is supplied to the wheel cylinder 40 by the hydraulic pressure supply device 100 operated by the signal of the unit to perform braking. At this time, the electronic control unit controls the hydraulic pressure supply device 100 so that the driver can provide the braking force of a desired size at a pressure increase ratio desired by the driver.

On the other hand, when the hydraulic pressure supply device 100 does not normally operate, the cut valves 261 and 262 are kept open even if the driver applies pressure to the brake pedal 10. Accordingly, the pressure provided by the master cylinder 20 is transmitted to the wheel cylinder 40 through the first and second backup channels 251 and 252.

However, since the size of the master cylinder 20 is limited, the limit value of the hydraulic pressure provided by the master cylinder 20 becomes smaller than the hydraulic pressure provided by the hydraulic pressure supply device 100. [ That is, when the vehicle is in an emergency, the driver does not provide the desired braking force or the driver can not provide the required pressure increase ratio.

To solve this problem, the electronic brake system according to the embodiment of the present invention further includes a boosting device 300 that can boost the hydraulic pressure generated in the master cylinder 20 in an emergency and deliver it to the wheel cylinder 40.

Referring to FIG. 2, the booster 300 may be provided between the reservoir 30 and the master cylinder 20. For example, in a second reservoir passage 62 connecting the second reservoir chamber 32 and the second master chamber 20b.

The booster 300 includes pump units 310 and 320 provided in the third reservoir flow path 63 connected to the middle of the second reservoir flow path 62. The pump unit may include a motor 320 operated by an instruction of a boost control unit (not shown) and a pump 310 operating by a driving force of the motor 320 to boost the hydraulic pressure. Here, the step-up control unit may be provided integrally with or separate from the electronic control unit for issuing a command to the hydraulic pressure supply device 100. [ In the case where the voltage-up control apparatus is provided separately from the electronic control unit, even when the hydraulic pressure supply apparatus 100 is not normally operated due to a failure of the electronic control unit, the voltage-up control apparatus can issue a command to the voltage- It is advantageous.

First and second check valves 311 and 312 may be provided at the front end and the rear end of the pump 310, respectively. The first and second check valves 311 and 312 are configured to transfer oil only in the direction of the master cylinder 20 from the reservoir 30 and not to transmit oil in the opposite direction. Or a check valve may be provided only at either the front end or the rear end of the pump 310, unlike the drawing.

The booster 300 includes a first control valve 330 provided in a fourth reservoir flow path 64 provided in parallel with the third reservoir flow path 63 and third and fourth reservoir flow paths 63 and 64 And a second control valve 340 provided in a fifth reservoir passage 65 provided in parallel.

The first control valve 330 may be provided as a solenoid valve for controlling the bidirectional oil flow between the reservoir 30 and the master cylinder 20. Specifically, the first control valve 330 may be provided with a normally open type solenoid valve that is normally open and operates to close the valve when receiving a close signal from the boost control unit.

The second control valve 340 may be provided as a check valve that transmits oil only in the direction of the master cylinder 20 from the reservoir 30 and does not transmit oil in the opposite direction.

When it is not necessary to increase the hydraulic pressure of the master cylinder 20, the first control valve 330 can be opened. The oil of the reservoir 30 may be filled into the master cylinder 20 through the first control valve 330 and the oil of the master cylinder 20 may return to the reservoir 30.

Conversely, when it is necessary to increase the hydraulic pressure of the master cylinder 20, the first control valve 330 can be switched to the closed state. Therefore, the oil in the reservoir 30 flows into the third reservoir flow path 63, is increased in pressure through the pump 310, and is transferred to the master cylinder 20.

The second control valve 340 can deliver the oil of the reservoir 30 to the master cylinder 20 so that emergency braking is possible even when the first control valve 330 is not opened.

On the other hand, the first control valve 330 can also be used as a diagnostic valve in the inspection mode. The inspection mode is a mode for checking whether a pressure is lost by generating a hydraulic pressure in the hydraulic pressure supply device 100 to check whether the simulator valve 54 is leaking. If the hydraulic pressure discharged from the hydraulic pressure supply device 100 flows into the reservoir 30 and pressure loss occurs, it is difficult to know whether or not the simulator valve 54 has leaked.

Therefore, in the inspection mode, the hydraulic circuit connected to the hydraulic pressure supply device 100 by closing the first control valve 330 can be constituted by a closed circuit. That is, by closing the first control valve 330, the simulator valve 54, and the outlet valve (not shown), the flow path connecting the hydraulic pressure supply device 100 and the reservoir 30 can be shut off to constitute a closed circuit.

The booster 300 further includes a booster sensor 350 installed at the lower end of the pump 310 to measure the hydraulic pressure. The boost sensor 350 measures the hydraulic pressure discharged from the pump 310 and the boost control unit can increase the rotation speed of the motor 320 when the magnitude of the hydraulic pressure discharged from the pressure sensor 350 is small . Specifically, when the driver depresses the brake pedal 10, the target pressure required by the driver is estimated based on the pedal information including the pedal stroke and the pedal pressure, and feedback control is performed through the pressure sensor 350 .

The brake system according to the embodiment of the present invention is different from that of the first embodiment in that a first hydraulic circuit 201 is connected to a wheel cylinder 40 provided on the front wheels FR and FL, May be connected to a wheel cylinder 40 provided in the wheel cylinders RR, RL. That is, the first master chamber 20a transmits hydraulic pressure to the wheel cylinders 40 provided on the front wheels FR and FL through the first backup hydraulic oil line 251 and the first hydraulic oil circuit 201, The chamber 20b transfers the hydraulic pressure to the wheel cylinders 40 provided on the rear wheels RR and RL through the second backup hydraulic line 252 and the second hydraulic circuit 202. [

Further, when braking the front wheels, the opening degree of the first control valve 330 is controlled to match the target braking pressure and the pressure rising speed, and pressure is generated by using the pump units 310 and 320. [ When the pressure reduction is requested, the first control valve 330 is controlled to release the hydraulic pressure of the master cylinder 20.

When the rear wheels are braked, the booster 300 can be used together with EPB (Electric Parking Brake) control. For example, it is possible to perform pressure control by feeding back the braking pressure from the EPB sensor mounted on the EPB.

3 is a graph showing the hydraulic pressure generated by the booster 300 according to the embodiment of the present invention in the input state of the brake pedal 10.

In the two graphs, A represents the hydraulic pressure generated by the booster 300 according to the embodiment of the present invention, and B represents the hydraulic pressure generated in the comparative example. The comparative example is a case where the booster 300 is not provided.

In the comparative example, the wheel cylinder 40 is operated only by the hydraulic pressure generated in the master cylinder 20 in an emergency in which the hydraulic pressure supply device 100 does not normally operate. Therefore, a sufficient braking pressure desired by the driver is not provided, and the braking pressure is not generated at a speed desired by the driver.

However, in the embodiment of the present invention, the hydraulic pressure generated by the booster 300 is added to the hydraulic pressure of the master cylinder 20 in an emergency, so that the wheel cylinder 40 is operated. Therefore, And the driver can quickly generate the braking pressure at a desired speed.

4 is a graph showing the hydraulic pressure generated by the booster 300 according to the embodiment of the present invention in a non-input state of the brake pedal 10.

In the two graphs, C represents the hydraulic pressure generated by the booster 300 according to the embodiment of the present invention, and D represents the hydraulic pressure generated in the comparative example. The comparative example is a case where the booster 300 is not provided.

Even when the driver does not apply pressure to the brake pedal 10, the braking force may be required. For example, in a situation where an ACC (Adaptive Cruse Control), a Traffic Jam Assist (TJA), or an AEB (Autonomous Emergency Braking) operation is performed, the driver does not need to step on the brake pedal 10 or the driver's brake pedal 10 input The hydraulic pressure supply device 100 may need to be operated to generate the braking pressure.

D, it can be seen that, in the comparative example, when the hydraulic pressure supply device 100 does not operate normally, it is impossible to generate the braking pressure.

However, in the embodiment of the present invention, when it is determined that the vehicle is in an emergency, the boost control device can operate the booster 300 to generate the hydraulic pressure.

5 is a flowchart showing conditions under which the booster 300 operates.

The boost control device (not shown) determines whether it is in an abnormal state (410). In the abnormal state, when an abnormality occurs in the hydraulic pressure supply apparatus 100 itself, when an abnormality occurs in a valve or the like in the hydraulic control unit 200, or when a sufficient hydraulic pressure is not generated due to a leak in the simulator valve 54, A case where an abnormality occurs in the control unit, and the like.

If it is determined that the vehicle is in a normal state, the electronic control unit operates the hydraulic pressure supply apparatus 100 to generate a braking pressure (430). If it is determined that the hydraulic pressure in the master cylinder 30 is abnormal, the booster control device operates the booster 300 to boost the hydraulic pressure of the master cylinder 30 (420).

10: Brake pedal 11: Pedal displacement sensor
20: master cylinder 30: reservoir
40: Wheel cylinder 50: Simulation device
54: simulator valve 60: check valve
61: first reservoir flow path 62: second reservoir flow path
63: third reservoir flow path 64: fourth reservoir flow path
65: Fourth reservoir flow path 66: Bypass flow path
67: check valve 100: hydraulic pressure supply device
200: Hydraulic control unit 201: First hydraulic circuit
202: second hydraulic circuit 211: first hydraulic oil
212: second hydraulic oil passage 251: first backup oil passage
252: second backup passage 261: first cut valve
262: second cut valve
300: booster 310: pump unit
311: first check valve 312: second check valve
320: motor 330: first control valve
340: second control valve 350: step-up sensor

Claims (12)

A master cylinder connected to a reservoir in which oil is stored and having a master chamber and a master piston provided in the master chamber to discharge the oil according to the pressure of the brake pedal;
A pedal simulator for providing a reaction force in response to the power of the brake pedal, the pedal simulator being connected to the master cylinder and having a simulator chamber in which oil is received;
A hydraulic control unit for controlling the flow of hydraulic pressure transmitted between the master cylinder and the wheel cylinder;
A hydraulic pressure supply device that operates by an electrical signal outputted in response to displacement of the brake pedal to supply hydraulic pressure to the hydraulic control unit; And
And a boosting device for boosting a hydraulic pressure delivered from the master cylinder to the hydraulic control unit when the hydraulic pressure supply device is operating abnormally. The method according to claim 1,
Wherein the booster is provided in a reservoir passage connecting the reservoir and the master cylinder. 3. The method of claim 2,
The master cylinder includes a first master piston directly pressurized by the brake pedal, a first master chamber in which the first master piston is accommodated, a second master piston indirectly urged by the first master piston, And a second master chamber in which the second master piston is received,
The hydraulic control unit includes a first hydraulic circuit and a second hydraulic circuit that supply hydraulic pressure to at least one wheel cylinder, respectively,
The first master chamber communicates with the reservoir through a first reservoir passage and is connected to the first hydraulic circuit through a first backup passage,
The second master chamber communicates with the reservoir through a second reservoir passage and is connected to the second hydraulic circuit through a second backup passage,
Wherein the booster is provided in the second reservoir channel. The method of claim 3,
Wherein a hydraulic pressure of the first master chamber is transmitted to the first hydraulic circuit when the hydraulic pressure supply device operates abnormally and a hydraulic pressure discharged from the booster is added to the hydraulic pressure of the second master chamber, To the electronic brake system. 5. The method of claim 4,
Wherein the first hydraulic circuit includes a wheel cylinder provided on one of a front wheel and a rear wheel and the second hydraulic circuit includes a wheel cylinder provided on the other of the front wheel and the rear wheel. The method according to claim 1,
When the hydraulic pressure supply device is operating abnormally and the driver provides the brake pedal with pressure,
Wherein the hydraulic pressure provided by the booster is added to the hydraulic pressure of the master cylinder by the driver's power and is transmitted to the wheel cylinder. The method according to claim 1,
When the hydraulic pressure supply device is operating abnormally and the driver does not provide the brake pedal with power,
Wherein the hydraulic pressure provided by the booster is transmitted to the wheel cylinder through the master cylinder. 3. The method of claim 2,
Wherein the booster includes a pump unit provided in a second reservoir flow passage and a first booster valve provided in a third reservoir flow passage bypassing the second reservoir flow passage. 9. The method of claim 8,
Wherein the booster further comprises a second booster valve provided in a fourth reservoir flow path for bypassing the second and third reservoir flow paths,
Wherein the first pressure-rising valve is provided with a bidirectional valve for controlling the flow in both directions,
Wherein the second pressure-rising valve is provided as a one-way valve allowing only flow from the reservoir to the master cylinder. 10. The method of claim 9,
Wherein the booster further includes a pressure sensor provided at a rear end of the reservoir flow path in which the second to fourth reservoir flow paths are merged. The method of claim 3,
A one-way valve provided in the first reservoir passage and allowing only the flow from the reservoir to the master cylinder,
Further comprising a check valve provided in a bypass flow path for bypassing the first reservoir flow path and controlling flow in both directions,
Wherein the booster includes a pump unit provided in a second reservoir flow passage and a booster valve provided in a third reservoir flow passage bypassing the second reservoir flow passage. A method for controlling an electronic brake system according to claim 1,
Determines whether the hydraulic pressure supply device is in a normal state,
Wherein when the hydraulic pressure supply device is determined to be in a normal state, the hydraulic pressure supply device is operated to generate a braking pressure of the wheel cylinder,
And when the hydraulic pressure supply device is determined to be in an abnormal state, operates the booster to generate the braking pressure of the wheel cylinder.

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