ELECTRONIC BRAKE SYSTEM

An electronic brake system is disclosed. The electronic brake system according to the present embodiment comprises: a first block in which arranged is a mechanical part that is linked with a brake pedal to be mechanically operated; a second block in which arranged is an electronic part that is electronically operated and controlled by an electronic control unit; an emergency module which operates when the electronic part is inoperative, and secondarily provides a fluid pressure; and connection lines which hydraulically connect the first block and the second block and the emergency module, wherein the first block and the second block and the emergency module may be installed at positions spaced from each other in a vehicle, and thus the mountability of the brake system and the degree of freedom in designing a vehicle may be improved.

TECHNICAL FIELD

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

BACKGROUND ART

A brake system for performing braking is essentially installed on a vehicle, and various types of brake systems have been proposed for the safety of drivers and passengers.

In a conventional brake system, a method of supplying hydraulic pressure required for braking to wheel cylinders using a mechanically connected booster when a driver presses a brake pedal has been mainly used. However, as market demands to implement various braking functions in a detailed response to operation environments of vehicles increase, in recent years, an electronic brake system, which receives a driver's intention to brake as an electrical signal from a pedal displacement sensor that detects a displacement of a brake pedal when the driver presses the brake pedal and operates a hydraulic pressure supply device based on the electrical signal to supply hydraulic pressure required for braking to wheel cylinders, has been widely used.

In such an electronic brake system, an electrical signal is generated and provided when the driver operates the brake pedal in a normal operation mode, and based on the electrical signal, the hydraulic pressure supply device is electrically operated and controlled to generate hydraulic pressure required for braking and transmit the hydraulic pressure to the wheel cylinders. As such, although such an electronic brake system is electrically operated and controlled so that complex and various braking operations may be implemented, when a technical problem occurs in an electric component, hydraulic pressure required for braking may not be stably generated, and thus the safety of passengers may be threatened.

Accordingly, the electronic brake system enters an abnormal operation mode when a component fails or becomes out of control, and in this case, a mechanism is required in which the driver's operation of the brake pedal is directly linked to the wheel cylinders. That is, in the abnormal operation mode of the electronic brake system, as the driver applies a pedal force to the brake pedal, hydraulic pressure required for braking needs to be generated immediately and transmitted directly to the wheel cylinders.

Meanwhile, when an electronic brake system is mounted on a vehicle, a degree of design freedom of the vehicle is limited due to the limitations of the size and installation position of a system module. Accordingly, a method capable of efficiently installing a system module while maintaining braking performance of a vehicle is required.

DISCLOSURE

Technical Problem

The present invention is directed to providing an electronic brake system capable of effectively implementing braking in various operating situations.

The present invention is directed to providing an electronic brake system with improved performance and operational reliability.

The present invention is directed to providing an electronic brake system capable of providing a stable pedal feeling to a driver in various operating situations.

The present invention is directed to providing an electronic brake system capable of improving a degree of design freedom of a vehicle.

The present invention is directed to providing an electronic brake system capable of performing easily and efficiently installing and disposing in the vehicle.

Technical Solution

One aspect of the present invention provides an electronic brake system including a first block in which a mechanical unit linked with a brake pedal to be mechanically operated is disposed, a second block in which an electronic unit electronically operated and controlled by an electronic control unit is disposed and which is disposed to be spaced apart from the first block, an emergency module operating when the electronic unit is inoperative and secondarily providing hydraulic pressure to a wheel cylinder, and a connection line hydraulically connecting the first block, the second block, and the emergency module, wherein the mechanical unit may include an integrated master cylinder having a first master piston connected to the brake pedal, a first master chamber whose volume is variable by a displacement of the first master piston, a second master piston provided to be displaceable by the displacement of the first master piston, a second master chamber whose volume is variable by a displacement of the second master piston, and a pedal simulator provided between the first master piston and the second mater piston, the electronic unit may include a hydraulic pressure supply device generating a hydraulic pressure by operating a hydraulic piston by an electrical signal output in response to a displacement of the brake pedal or an electrical signal output from the electronic control unit and a hydraulic control unit having a plurality of flow paths and valves to control the hydraulic pressure transmitted from the hydraulic pressure supply device to the wheel cylinder, the emergency module may include a hydraulic pressure auxiliary device operating when the hydraulic pressure supply device is inoperative and providing hydraulic pressure to the wheel cylinder, and the connection line may include a first connection line having one end connected to the second master chamber and the other end connected to the hydraulic control unit.

The hydraulic control unit may include a first hydraulic circuit controlling hydraulic pressure transmitted to a first wheel cylinder and a second wheel cylinder and a second hydraulic circuit controlling hydraulic pressure transmitted to a third wheel cylinder and a fourth wheel cylinder, and the hydraulic pressure auxiliary device may be provided between the first and second wheel cylinders and the first hydraulic circuit.

The other end of the first connection line may be connected between the first hydraulic circuit and the hydraulic pressure auxiliary device.

The electronic unit may further include at least one cut value provided in the first connection line and controlling a flow of a pressurized medium.

The first hydraulic circuit may include a first inlet valve and a second inlet valve respectively controlling flows of the pressurized medium supplied to the first wheel cylinder and the second wheel cylinder, and the other end of the first connection line may be branched and connected to a downstream side of each of the first and second inlet valves.

The electronic unit may further include a sub-reservoir in which a pressurized medium is stored, a dump flow path connecting the second hydraulic circuit and the sub-reservoir, and a dump valve provided on the dump flow path and controlling a flow of the pressurized medium.

The second hydraulic circuit may include a third inlet valve and a fourth inlet valve respectively controlling flows of the pressurized medium supplied to the third wheel cylinder and the fourth wheel cylinder, and the dump flow path may have one end connected to the sub-reservoir and the other end connected to an upstream side of each of the third and fourth inlet valves.

The hydraulic pressure auxiliary device may include a first isolation valve and a second isolation valve respectively allowing and blocking flows of the pressurized medium transmitted from the integrated master cylinder and the hydraulic pressure supply device to the first wheel cylinder and the second wheel cylinder, a pump pressurizing the pressurized medium, a motor driving the pump, a first auxiliary hydraulic flow path transmitting the pressurized medium pressurized by the pump to the first wheel cylinder, and a second auxiliary hydraulic flow path transmitting the pressurized medium pressurized by the pump to the second wheel cylinder.

The hydraulic pressure auxiliary device may further include a first auxiliary dump flow path discharging the pressurized medium applied to the first wheel cylinder and a second auxiliary dump flow path discharging the pressurized medium applied to the second wheel cylinder.

The hydraulic pressure auxiliary device may further include a first support valve provided on the first auxiliary hydraulic flow path to control the flow of the pressurized medium, a second support valve provided on the second auxiliary hydraulic flow path to control the flow of the pressurized medium, a first discharge valve provided on the first auxiliary dump flow path to control the flow of the pressurized medium, and a second discharge valve provided on the second auxiliary dump flow path to control the flow of the pressurized medium.

The connection line may further include a second connection line having one end connected to a sub-reservoir and the other end connected to the hydraulic pressure auxiliary device, and the other end of the second connection line may be connected to an inlet end of the pump and the first and second auxiliary dump flow paths.

The mechanical unit may further include a main reservoir in which the pressurized medium is stored, and the connection line may further include a third connection line having one end connected to the main reservoir and the other end connected to the sub-reservoir.

The first connection line may be provided as a pipe having rigidity, and the second connection line and the third connection line may be provided as hoses having elasticity.

The electronic unit may be provided further including a dump control unit provided between the sub-reservoir and the hydraulic pressure supply device to control the flow of a pressurized medium.

The second hydraulic circuit may further include a first outlet valve and a second outlet valve respectively controlling flows of the pressurized medium discharged from the third wheel cylinder and the fourth wheel cylinder to the sub-reservoir.

Advantageous Effects

An electronic brake system according to the present embodiment can stably and effectively implement braking in various operating situations of a vehicle.

An electronic brake system according to the present embodiment can improve performance and operational reliability of the product.

An electronic brake system according to the present embodiment can stably provide a braking pressure even when a component fails.

An electronic brake system according to the present embodiment can improve a degree of design freedom of the vehicle.

An electronic brake system according to the present embodiment can easily and efficiently perform installing and disposing in the vehicle.

An electronic brake system according to the present embodiment can provide a stable pedal feeling to a driver in various operating situations.

MODES OF THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided to fully convey the spirit of the present invention to a person having ordinary skill in the art to which the present invention belongs. The present invention is not limited to the embodiments shown herein but may be embodied in other forms. The drawings may omit the illustration of parts not related to the description in order to clarify the present invention, and slightly exaggerate the size of the components to help understanding.

FIG.1is a hydraulic circuit diagram illustrating an electronic brake system1according to an embodiment of the present invention.

Referring toFIG.1, the electronic brake system1according to the embodiment of the present invention may include a first block100in which a mechanical unit mechanically operated is disposed, a second block200in which an electronic unit electronically operated and controlled is disposed, an emergency module300which operates when the electronic unit is inoperative, and secondarily provides hydraulic pressure, and a plurality of connection lines400hydraulically connecting the first block100, the second block200, and the emergency module300.

In the first block100, the mechanical unit mechanically operated by being connected and linked with a brake pedal10is disposed, and in the second block200, the electronic unit electronically operated and controlled is disposed such as a valve, a sensor, and the like whose operation is controlled by an electronic control unit (not shown). The first block100and the second block200may be disposed to be spaced apart from each other in a vehicle, while hydraulically connected by the plurality of connection lines400, and thus mountability of the electronic brake system1on the vehicle may be improved and furthermore a degree of design freedom of the vehicle may be improved so that efficient space arrangement may be possible. In addition, the emergency module300may be disposed in the second block200or disposed to be spaced apart from the second block200in the vehicle.

The mechanical unit may include components performing mechanical operations linked with the brake pedal10irrespective of a control signal of the electronic control unit and may be disposed in the first block100.

The mechanical unit may include a main reservoir1100ain which a pressurized medium such as brake oil or the like is stored, an integrated master cylinder1200that provides a reaction force according to a pedal force of the brake pedal10to a driver and pressurizes and discharges the pressurized medium such as brake oil or the like accommodated therein, and main reservoir flow paths1110aand1120aconnecting the main reservoir1100aand the integrated master cylinder1200.

The integrated master cylinder1200is provided to, when the driver applies a pedal force to the brake pedal10for braking operation, provide a reaction force thereagainst to the driver to provide a stable pedal feeling, and at the same time pressurize and discharge the pressurized medium accommodated therein by the operation of the brake pedal10.

In the integrated master cylinder1200, a simulation unit providing a pedal feeling to the driver and a master cylinder unit pressurizing and discharging the pressurized medium accommodated therein by a pedal force of the brake pedal may be disposed coaxially in a cylinder body1210.

Specifically, the integrated master cylinder1200may include the cylinder body1210having a chamber formed therein, a first master chamber1220aformed on an inlet side of the cylinder body1210to which the brake pedal10is connected, a first master piston1220provided in the first master chamber1220aand connected to the brake pedal10to be displaceable by the operation of the brake pedal10, a second master chamber1230aformed on an inner or front side (left side ofFIG.1) of the first master chamber1220aon the cylinder body1210, a second master piston1230provided in the second master chamber1230aand provided to be displaceable by a displacement of the first master piston1220or hydraulic pressure of the pressurized medium accommodated in the first master chamber1220a, and a pedal simulator1240disposed between the first master piston1220and the second master piston1230to provide a pedal feeling through an elastic restoring force generated during compression.

The first master chamber1220aand the second master chamber1230amay be sequentially formed toward the inside (left side ofFIG.1) from the brake pedal10(right side ofFIG.1) on the cylinder body1210of the integrated master cylinder1200. Also, the first master piston1220and the second master piston1230may be provided in the first master chamber1220aand the second master chamber1230a, respectively, to generate hydraulic pressure or generate negative pressure by the pressurized medium accommodated in the respective chambers depending on forward or backward movement.

The cylinder body1210may include a large diameter portion1211with the first master chamber1220aformed therein and an inner diameter formed to be relatively large and a small diameter portion1212with the second master chamber1230aformed therein and an inner diameter formed to be smaller than the large diameter portion1211. The large diameter portion1211and the small diameter portion1212of the cylinder body1210may be integrally formed.

The first master chamber1220amay be formed at an inner side of the large diameter portion1211, that is, on an inlet side or rear side (right side ofFIG.1) of the cylinder body1210, and the first master piston1220connected to the brake pedal10via an input rod12may be accommodated in the first master chamber1220ato be reciprocally movable.

The pressurized medium may be introduced into and discharged from the first master chamber1220athrough a first hydraulic port1280aand a second hydraulic port1280b. The first hydraulic port1280ais connected to an auxiliary reservoir flow path1130a, which will be described below, so that the pressurized medium may be introduced into the first master chamber1220afrom the main reservoir1100a, and the second hydraulic port1280bis connected to a first main reservoir flow path1110a, which will be described below, so that the pressurized medium may be introduced into the first master chamber1220afrom the main reservoir1100a, or conversely, the pressurized medium may be discharged into the main reservoir1100afrom the first master chamber1220a.

A pair of sealing members may be provided in front and rear of the first hydraulic port1280a. The pair of sealing members may allow the flow of the pressurized medium from the main reservoir1100atoward the first master chamber1220aand block the flow of the pressurized medium discharged from the first master chamber1220ato the auxiliary reservoir flow path1130a.

The first master piston1220may be accommodated and provided in the first master chamber1220a, and may generate hydraulic pressure by pressurizing the pressurized medium accommodated in the first master chamber1220aby moving forward (left direction ofFIG.1) or pressurize the pedal simulator1240to be described below, and generate negative pressure inside the first master chamber1220aby moving backward (right direction ofFIG.1). The first master piston1220may include a first body1221formed in a cylindrical shape to be in close contact with an inner-circumferential surface of the first master chamber1220aand a first flange1222formed by extending in a radial direction at a rear end (right end portion ofFIG.1) of the first body1221and to which the input rod12is connected. The first master piston1220may be elastically supported by a first piston spring1220b, and the first piston spring1220bmay be provided with one end supported by a front surface (left surface ofFIG.1) of the first flange1222and the other end supported by an outer surface of the cylinder body1210.

The second master chamber1230amay be formed on an inner side of the small diameter portion1212, that is, on the inner side or front side (left side ofFIG.1) of the cylinder body1210, and the second master piston1230may be accommodated in the second master chamber1230ato be reciprocally movable.

The pressurized medium may be introduced into and discharged from the second master chamber1230athrough a third hydraulic port1280cand a fourth hydraulic port1280d. The third hydraulic port1280cis connected to a second main reservoir flow path1120a, which will be described below, so that the pressurized medium may be introduced into the second master chamber1230afrom the main reservoir1100a, and the fourth hydraulic port1280dis connected to a first connection line, which will be described below, so that the pressurized medium accommodated in the second master chamber1230amay be discharged to the first connection line410, or conversely, the pressurized medium may be introduced into the second master chamber1230afrom the first connection line410.

A pair of sealing members may be provided in front and rear of the third hydraulic port1280c. The pair of sealing members may allow the flow of the pressurized medium introduced into the second master chamber1230afrom the main reservoir1100avia the second main reservoir flow path1120aand block the flow of the pressurized medium discharged from the second master chamber1230ato the second reservoir flow path1120a.

The second master piston1230may be accommodated and provided in the second master chamber1230a, and may generate hydraulic pressure of the pressurized medium accommodated in the second master chamber1230aby moving forward and generate negative pressure in the second master chamber1230aby moving backward. The second master piston1230may include a second body1231formed in a cylindrical shape to be in close contact with an inner-circumferential surface of the second master chamber1230aand a second flange1232formed by extending in a radial direction at a rear end portion (right end portion ofFIG.1) of the second body1231and disposed on an inner side of the first master chamber1220a. A diameter of the second flange1232may be formed to be larger than a diameter of the inner-circumferential surface of the second master chamber1230a. The second master piston1230may be elastically supported by a second piston spring1230b, and the second piston spring1230bmay be provided with one end supported by a front surface (left surface ofFIG.1) of the second body1231and the other end supported by an inner surface of the cylinder body1210.

The pedal simulator1240may be provided between the first master piston1220and the second master piston1230and provide a pedal feeling of the brake pedal10to the driver by its own elastic restoring force. Specifically, the pedal simulator1240may be interposed between the front surface of the first master piston1220and the rear surface of the second master piston1230and made of an elastic material such as compressible and expandable rubber or the like.

The pedal simulator1240may include a tapered portion1241at least partially inserted into and supported by the front surface of the first master piston1220and having a diameter gradually increasing in a forward direction (left side ofFIG.1) and a body portion1242with a cylindrical shape in contact with the rear surface of the second master piston1230or at least partially inserted into and supported by the rear surface. As both ends of the pedal simulator1240are inserted into or supported by the first master piston1220and the second master piston1230, respectively, the pedal simulator1240may be stably modified. Furthermore, as the tapered portion1241changes the elastic restoring force according to a pedal force of the brake pedal10, a stable and familiar pedal feeling may be provided to the driver.

When describing a pedal simulation operation by the integrated master cylinder1200, when the driver operates the brake pedal10in the normal operation mode, a cut valve411provided in the first connection line410, which will be described below, is closed simultaneously. As the operation of the brake pedal10progresses, the first master piston1220moves forward, but the second master chamber1230ais sealed by a closing operation of the cut valve411, so that a displacement of the second master piston1230is not generated. At this time, by the closing operation of the cut valve411, the pressurized medium accommodated in the first master chamber1220ais introduced into the main reservoir1100athrough the first main reservoir flow path1110a. The second master piston1230is unable to move forward, while the first master piston1220continuously moves forward to compress the pedal simulator1240, so that the elastic restoring force of the pedal simulator1240may be provided to the driver as a pedal feeling. Next, when the driver releases the pedal force of the brake pedal10, the first master piston1220and the pedal simulator1240may return to the original shape and position thereof by the first and second piston springs1220band1230band the elastic restoring force of the pedal simulator1240, and the first master chamber1220amay be filled with the pressurized medium supplied from the main reservoir1100athrough the first main reservoir flow path1110a.

Thus, because the insides of the first master chamber1220aand the second master chamber1230are always filled with the pressurized medium, when the pedal simulation is operated, friction of the first master piston1220and the second master piston1230is minimized, so that the durability of the integrated master cylinder1200may be improved, and the inflow of foreign substances from the outside may be blocked.

Meanwhile, the operation of the integrated master cylinder1200when the electronic brake system1operates abnormally, that is, in the operating state of a fallback mode will be described below with reference toFIGS.6and7.

The main reservoir1100amay accommodate and store the pressurized medium therein. The main reservoir1100amay be connected to each component such as the integrated master cylinder1200, a third connection line430, which will be described below, and the like, and supply or receive the pressurized medium.

The main reservoir1100amay be provided by being divided into a plurality of chambers by partition walls1105a. The main reservoir1100amay include a plurality of main reservoir chambers1101a,1102a, and1103a, and the plurality of main reservoir chambers1101a,1102a, and1103amay be disposed side by side in a single row. Specifically, the main reservoir1100amay be distinguished into a first main reservoir chamber1101adisposed at the center, a second main reservoir chamber1102adisposed at one side, and a third main reservoir chamber1103adisposed at the other side.

Each of the partition walls1105amay be provided between adjacent main reservoir chambers, and each of the partition walls1105amay be provided with at least a part of an upper end open. Thus, the adjacent main reservoir chambers1101a,1102a, and1103amay communicate with each other so that the pressurized medium may move. As an example, when a large amount of pressurized medium is introduced into the first main reservoir chamber1101a, the pressurized medium may pass over the upper end of the partition walls1105aand be transmitted to the second main reservoir chamber1102aor the third main reservoir chamber1103a.

The first main reservoir chamber1101amay be connected to the third connection line430, which will be described below, and supply the pressurized medium to a sub-reservoir1100bor receive the pressurized medium from the sub-reservoir1100b. In addition, the second main reservoir chamber1102amay be connected to the first main reservoir flow path1110aand the third main reservoir chamber1103amay be connected to the second main reservoir flow path1120aso that the second main reservoir chamber1102aand the third main reservoir chamber1103amay supply or receive the pressurized medium to or from the integrated master cylinder1200.

Thus, as the main reservoir1100ais provided by being divided into the first to third main reservoir chambers1101a,1102a, and1103a, stable operation of the electronic brake system1may be promoted. As an example, when the main reservoir1100ais formed as a single chamber and the capacity of the pressurized medium is not sufficient, the pressurized medium may not be stably supplied not only to the sub-reservoir1100bbut also to the integrated master cylinder1200. Accordingly, as the main reservoir1100ais provided by being divided into the first main reservoir chamber1101aconnected to the sub-reservoir1100bof the electronic unit and the second and third main reservoir chambers1102aand1103aconnected to the integrated master cylinder1200, even when the pressurized medium is not supplied to any one component, braking of the vehicle may be implemented by supplying the pressurized medium to another component.

A main reservoir flow path is provided to hydraulically connect the integrated master cylinder1200and the main reservoir1100a.

A reservoir flow path may include the first main reservoir flow path1110aconnecting the first master chamber1220aand the second reservoir chamber of the main reservoir1100aand the second reservoir flow path1120aconnecting the second master chamber1230aand the third reservoir chamber1103aof the main reservoir1100a. To this end, one end of the first main reservoir flow path1110amay communicate with the first master chamber1220aof the integrated master cylinder1200and the other end may communicate with the second main reservoir chamber1102aof the main reservoir1100a, and one end of the second main reservoir flow path1120amay communicate with the second master chamber1230aof the integrated master cylinder1200and the other end may communicate with the third reservoir chamber1103aof the main reservoir1100a.

The electronic unit may include components electronically operated and controlled by a control signal of an electronic control unit (ECU, not shown) and be disposed in the second block200.

The electronic unit may include the electronic control unit, a sub-reservoir1100bsecondarily storing the pressurized medium therein, a hydraulic pressure supply device1300receiving a driver's intention to brake as an electrical signal from a pedal displacement sensor11, which detects a displacement of the brake pedal10, and generating hydraulic pressure of the pressurized medium through a mechanical operation, a hydraulic control unit1400controlling hydraulic pressure provided from the hydraulic pressure supply device1300and hydraulic pressure transmitted to first to fourth wheel cylinders21,22,23and24, a dump flow path1800connecting the third and fourth wheel cylinders23and24and the sub-reservoir1100band a dump valve1810provided thereon to control a flow of the pressurized medium, a dump control unit1900hydraulically connecting the sub-reservoir1100band the hydraulic pressure supply device1300and controlling a flow of the pressurized medium therebetween, and a cut valve411provided in the first connection line410to control a flow of the pressurized medium.

The sub-reservoir1100bmay be disposed in the second block200and secondarily store the pressurized medium. As the pressurized medium is secondarily stored by the sub-reservoir1100bin the electronic unit, the pressurized medium may also be smoothly supplied and transmitted within the electronic unit such as the hydraulic pressure supply device1300, the dump control unit1900, first and second hydraulic circuits1510and1520, and the like.

The sub-reservoir1100bmay be connected to a hydraulic pressure auxiliary device1600of the emergency module300by a second connection line420, which will be described below, and connected to the main reservoir1100aof the electronic unit by the third connection line430. Besides, the sub-reservoir1100bmay be connected to pressure chambers1330and1340of the hydraulic pressure supply device1300through the dump control unit1900by a sub-reservoir flow path1110band connected to the second hydraulic circuit1520by the dump flow path1800which will be described below.

The sub-reservoir1100bmay be provided by being divided into a plurality of chambers by partition walls1105b. The sub-reservoir1100bmay include a plurality of sub-reservoir chambers1101b,1102b, and1103b, and the plurality of sub-reservoir chambers1101b,1102b, and1103bmay be disposed side by side in a single row. Specifically, the sub-reservoir1100bmay be distinguished into a first sub-reservoir chamber1101bdisposed at the center, a second sub-reservoir chamber1102bdisposed at one side, and a third sub-reservoir chamber1103bdisposed at the other side.

Each of the partition walls1105bmay be provided between adjacent sub-reservoir chambers, and each of the partition walls1105bmay be provided with at least a part of an upper end open. Thus, the adjacent sub-reservoir chambers1101b,1102b, and1103bmay communicate with each other so that the pressurized medium may move. As an example, when a large amount of pressurized medium is introduced into the first sub-reservoir chamber1101b, the pressurized medium may pass over the upper end of the partition walls1105band be transmitted to the second sub-reservoir chamber1102bor the third sub-reservoir chamber1103b.

The first sub-reservoir chamber1101band the second sub-reservoir chamber1102bmay be connected to the dump control unit1900by the sub-reservoir flow path1110bcommunicating therewith, which will be described below, and the second sub-reservoir chamber may supply the pressurized medium to the main reservoir1100aor receive the pressurized medium from the main reservoir1100aby being connected to the third connection line430, which will be described below. In addition, the third sub-reservoir chamber1103bmay be connected to the dump flow path1800, which will be described below, and a downstream side of each of first and second outlet valves1522aand1522bof the second hydraulic circuit1520, so that the pressurized medium may be transmitted thereto.

Thus, as the sub-reservoir1100bis provided by being divided into the first to third sub-reservoir chambers1101b,1102b, and1103b, the stable operation of the electronic brake system1may be promoted. As an example, when the sub-reservoir1100bis formed as a single chamber and the capacity of the pressurized medium is not sufficient, the pressurized medium may not be stably supplied not only to the main reservoir1100abut also to the dump control unit1900and the hydraulic pressure supply device1300. Accordingly, as the sub-reservoir1100bis provided by being divided into the first and second sub-reservoir chambers1101band1102bconnected to the dump control unit1900and the hydraulic pressure supply device1300, the second sub-reservoir chamber1102bconnected to the main reservoir1100aof the mechanical unit, and the third sub-reservoir chamber1103bconnected to the dump flow path1800and the outlet valves1522aand1522b, even when the pressurized medium is not supplied to any one component, braking of the vehicle may be implemented by supplying the pressurized medium to another component.

The hydraulic pressure supply device1300is provided to receive a driver's intention to brake as an electrical signal from the pedal displacement sensor11, which detects a displacement of the brake pedal10, implement reciprocating movement of a hydraulic piston1320, and thus generate hydraulic pressure of the pressurized medium.

The hydraulic pressure supply device1300may include a hydraulic pressure supply unit supplying a pressure of the pressurized medium transmitted to a wheel cylinder and a power supply unit (not shown) generating power of the hydraulic piston1320based on the electrical signal of the pedal displacement sensor11.

The hydraulic pressure supply unit includes a cylinder block1310provided to be capable of accommodating the pressurized medium, the hydraulic piston1320accommodated in the cylinder block1310, and a sealing member provided between the hydraulic piston1320and the cylinder block1310to seal a pressure chamber.

The pressure chamber may include a first pressure chamber1330located in front side of the hydraulic piston1320(left side of the hydraulic piston1320inFIG.1) and a second pressure chamber1340located in the rear side of the hydraulic piston1320(right side of the hydraulic piston1320inFIG.1). That is, the first pressure chamber1330is provided to be partitioned by the cylinder block1310and a front surface of the hydraulic piston1320so that a volume thereof changes according to a movement of the hydraulic piston1320, and the second pressure chamber1340is provided to be partitioned by the cylinder block1310and a rear surface of the hydraulic piston1320so that a volume thereof changes according to the movement of the hydraulic piston1320.

The first pressure chamber1330may be hydraulically connected to the hydraulic control unit1400, which will be described below, by a hydraulic flow path, and the second pressure chamber1340may also be hydraulically connected to the hydraulic control unit1400by a hydraulic flow path.

The sealing member includes a piston sealing member1351provided between the hydraulic piston1320and the cylinder block1310to seal between the first pressure chamber1330and the second pressure chamber1340, and a drive shaft sealing member1352provided between the power supply unit and the cylinder block1310to seal between the second pressure chamber1340and an opening of the cylinder block1310. Hydraulic pressure or negative pressure of the first pressure chamber1330and the second pressure chamber1340generated by the forward or backward movement of the hydraulic piston1320may not leak by being sealed by the piston sealing member1351and the drive shaft sealing member1352and may be transmitted to each of the hydraulic flow paths.

The power supply unit may generate and supply power of the hydraulic piston1320by an electrical signal. As an example, the power supply unit may include a motor (not shown) generating a rotational force and a power conversion unit (not shown) converting the rotational force of the motor into a translational movement of the hydraulic piston1320, but is not limited the corresponding structure and device.

The dump control unit1900may be provided between the hydraulic pressure supply device1300and the sub-reservoir1100bto control a flow of the pressurized medium, and to this end, include a plurality of flow paths and various types of solenoid valves. One end of the dump control unit1900may be connected to the first pressure chamber1330and the second pressure chamber1340of the hydraulic pressure supply device1300, and the other end may be connected to the first sub-reservoir chamber1101bof the sub-reservoir1100bby the sub-reservoir flow path1110a. The plurality of solenoid valves provided in the dump control unit1900are electrically operated and controlled by an electronic control unit.

The first pressure chamber1330and the second pressure chamber1340may be connected to the sub-reservoir1100bvia the dump control unit1900. Through the dump control unit1900, the first pressure chamber1330and the second pressure chamber1340may receive the pressurized medium from the sub-reservoir1100b, and conversely, transmit the pressurized medium accommodated in the first pressure chamber1330and the second pressure chamber1340to the sub-reservoir1100b.

The hydraulic control unit1400is provided between the hydraulic supply device1300and the wheel cylinder, and an operation thereof is controlled by the electronic control unit so that the hydraulic pressure transmitted to the wheel cylinders21,22,23, and24may be adjusted.

The hydraulic control unit1400may have the first hydraulic circuit1510controlling a flow of the hydraulic pressure transmitted to the first and second wheel cylinders21and22among the four wheel cylinders21,22,23, and24and the second hydraulic circuit1520controlling a flow of the hydraulic pressure transmitted to the third and fourth wheel cylinders23and24, and includes a plurality of hydraulic flow paths and solenoid valves to control the hydraulic pressure transmitted from the integrated master cylinder1200and the hydraulic pressure supply device1300to the wheel cylinders.

The first and second hydraulic circuits1510and1520may include first to fourth inlet valves1511a,1511b,1521a, and1521brespectively controlling flows of the pressurized medium toward the first to fourth wheel cylinders21,22,23, and24. The first to fourth inlet valves1511a,1511b,1521a, and1521bmay be disposed at upstream sides of the first to fourth wheel cylinders21,22,23, and24, respectively, and provided as normal open type solenoid valves that operate to be closed when receiving an electrical signal from the electronic control unit in a normally opened state.

The first and second hydraulic circuits1510and1520may include first to fourth check valves1513a,1513b,1523a, and1523bprovided to be connected in parallel with respect to the first to fourth inlet valves1511a,1511b,1521a, and1521b. The first to fourth check valves1513a,1513b,1523a, and1523bmay be provided on bypass flow paths that connect front sides and rear sides of the first to fourth inlet valves1511a,1511b,1521a, and1521bon the first and second hydraulic circuits1510and1520, and may allow only the flow of the pressurized medium discharged from each of the wheel cylinders and block the flow of the pressurized medium from the hydraulic pressure supply device1300to the wheel cylinders. By the first to fourth check valves1513a,1513b,1523a, and1523b, the hydraulic pressure of the pressurized medium applied to each of the wheel cylinders may be quickly released, and even when the first to fourth inlet valves1511a,1511b,1521a, and1521bdo not operate normally, the hydraulic pressure of the pressurized medium applied to the wheel cylinders may be smoothly discharged.

The second hydraulic circuit1520may include the first and second outlet valves1522aand1522bcontrolling discharge of the pressurized medium to improve performance when braking of the third and fourth wheel cylinders23and24is released. The first and second outlet valves1522aand1522bmay detect braking pressure of each of the third and fourth wheel cylinders23and24and be selectively opened when decompression braking is required such as in an ABS dump mode or the like to discharge the pressurized medium applied to the third and fourth wheel cylinders23and24to the sub-reservoir1100b. The first and second outlet valves1522aand1522bmay be provided as normal closed type solenoid valves that operate to be opened when receiving an electrical signal from the electronic control unit in a normally closed state

Meanwhile, the electronic brake system1according to the present embodiment includes a first fallback mode, in which the hydraulic pressure auxiliary device1600of the emergency module300, which will be described below, intervenes when the electronic unit such as the hydraulic pressure supply device1300and the like is inoperative, and a second fallback mode in which the pressurized medium is directly transmitted from the integrated master cylinder1200to the first and second wheel cylinders21and22to perform braking when both the electronic unit and the hydraulic pressure auxiliary device1600are inoperative. Herein, in a state in which the hydraulic pressure of the pressurized medium is applied from the hydraulic pressure supply device1300to the third and fourth wheel cylinders23and24, when switched to the first fallback mode or the second fallback mode, the hydraulic pressures applied to each wheel cylinder may be different so that behavior control of the vehicle may be difficult. Accordingly, in the first fallback mode or the second fallback mode, the hydraulic pressure applied to the third and fourth wheel cylinders23and24should be removed. To this end, the electronic unit includes the dump flow path1800connecting the second hydraulic circuit1520, in which the hydraulic pressure auxiliary device1600is not installed, and the sub-reservoir1100b.

Specifically, one end of the dump flow path1800may be connected to the third reservoir chamber1103aof the sub-reservoir1100b, and the other end may be connected to a front end or upstream side of each of the third and fourth inlet valves1521aand1521bin the second hydraulic circuit1520, and in the dump flow path1800, the dump valve1810controlling a flow of the pressurized medium may be provided. The dump valve1810may be provided as a normal open type solenoid valve that operates to be closed when receiving an electrical signal from the electronic control unit in a normally opened state

As the dump valve1810is controlled to a closed state in a normal operation mode, the hydraulic pressure provided by the hydraulic pressure supply device1300may not leak into the sub-reservoir1100bbut be supplied to the third and fourth wheel cylinders23and24through the second hydraulic circuit1520. However, when the electronic brake system1enters the first fallback mode or the second fallback mode, the dump valve1810may be switched to an opened state so that the pressurized medium applied to the third and fourth wheel cylinders23and24may be discharged to the sub-reservoir1100band thus the behavior of the vehicle may be stably controlled.

The electronic unit may include at least one cut value411provided in the first connection line410, which will be described below, and controlling the flow of the pressurized medium. A detailed description thereabout will be presented below.

The electronic brake system1according to the present embodiment further include a plurality of pressure sensors P disposed in a variety of flow paths to detect the hydraulic pressure of the pressurized medium. InFIG.1, the pressure sensors P are illustrated as being disposed on each of the second master chamber1230a, the second hydraulic circuit1520, and the hydraulic pressure auxiliary device1600, but are not limited to the corresponding positions and may include a case of being provided in various positions to detect the hydraulic pressure of the pressurized medium.

Meanwhile, when, in the electronic unit, the hydraulic pressure supply device1300is inoperative such as a failure or the hydraulic control unit1400is uncontrollable, the hydraulic pressure is not transmitted to the wheel cylinders21,22,23, and24, and thus there is a problem that active braking of the vehicle becomes difficult. Accordingly, the electronic brake system1according to the present embodiment is provided with the emergency module300that operates and intervene to secondarily supply the hydraulic pressure of the pressurized medium when the electronic unit is inoperative due to the failure of the hydraulic pressure supply device1300or the like.

The emergency module300includes the hydraulic pressure auxiliary device1600, which operates and intervenes when the electronic unit such as the hydraulic pressure supply device1300or the like is inoperative, and may be mounted and installed in the vehicle by being disposed together in the second block200, in which the electronic unit is disposed, or spaced apart from the second block200.

The hydraulic pressure auxiliary device1600may be provided at the first and second wheel cylinders21and22of the first hydraulic circuit1510and operate when the hydraulic pressure supply device1300is inoperative due to the failure or the like to generate and provide hydraulic pressure required for braking of the first and second wheel cylinders21and22. A mode, in which the hydraulic pressure auxiliary device1600operates due to inoperativeness of the hydraulic pressure supply device1300, is referred to as the first fallback mode.

The hydraulic pressure auxiliary device1600includes a first isolation valve1651controlling a flow of the pressurized medium transmitted from at least any one of the integrated master cylinder1200or the hydraulic pressure supply device1300to the first wheel cylinder21, a second isolation valve1652controlling a flow of the pressurized medium transmitted from at least any one of the integrated master cylinder1200or the hydraulic pressure supply device1300to the second wheel cylinder22, a pair of pumps1620pressurizing the pressurized medium, a motor1610driving the pair of pumps1620, a first auxiliary hydraulic flow path1631transmitting the pressurized medium pressurized by the pumps1620to the first wheel cylinder21, a second auxiliary hydraulic flow path1632transmitting the pressurized medium pressurized by the pumps1620to the second wheel cylinder22, a first support valve1631aprovided in the first auxiliary hydraulic flow path1631to control the flow of the pressurized medium, a second support valve1632aprovided in the second auxiliary hydraulic flow path1632to control the flow of the pressurized medium, a first auxiliary dump flow path1641discharging the pressurized medium applied to the first wheel cylinder21, a second auxiliary dump flow path1642discharging the pressurized medium applied to the second wheel cylinder22, a first discharge valve1641aprovided in the first auxiliary dump flow path1641to control the flow of the pressurized medium, and a second discharge valve1642aprovided in the second auxiliary dump flow path1642to control the flow of the pressurized medium.

The first and second isolation valves1651and1652are provided to allow or block a hydraulic connection between any one of the integrated master cylinder1200and the hydraulic pressure supply device1300and the first and second wheel cylinders21and22, respectively.

When the hydraulic pressure of the pressurized medium generated by the pumps1620leaks into the hydraulic pressure supply device1300when the hydraulic pressure auxiliary device1600operates, a level of braking required by the driver is different from a braking force actually generated in each of the first and second wheel cylinders21and22so that there is a risk of a safety accident. In addition, when the hydraulic pressure generated and provided by the hydraulic pressure auxiliary device1600is not wholly transmitted to the first and second wheel cylinders21and22but leaks into a component on the other side, there is a problem that quick braking of the wheel cylinders is not implemented.

Accordingly, the first and second isolation valves1651and1652may allow the hydraulic connection of the integrated master cylinder1200and the hydraulic pressure supply device1300to the first and second wheel cylinders21and22in the normal operation mode and the second fallback mode and block the hydraulic connection of the integrated master cylinder1200and the hydraulic pressure supply device1300to the first and second wheel cylinders21and22in the first fallback mode.

The first isolation valve1651may be provided between the first wheel cylinder21and the downstream side of the first inlet valve1511aand provided to allow and block the flow of the pressurized medium. The first isolation valve1651may be provided as a normal open type solenoid valve that operates to be opened when receiving an electrical signal from the electronic control unit in a normally opened state.

The second isolation valve1652may be provided between the second wheel cylinder22and the downstream side of the second inlet valve1512aand provided to allow and block the flow of the pressurized medium. The second isolation valve1652may be provided as a normal open type solenoid valve that operates to be opened when receiving an electrical signal from the electronic control unit in a normally opened state.

When it is determined that the hydraulic pressure supply device1300is inoperative due to a failure or the like, the electronic control unit may switch to the first fallback mode to close the first and second isolation valves1651and1652and operate the motor1610. The motor1610may be operated by receiving a driver's intention to brake as an electrical signal from the pedal displacement sensor11that detects a displacement of the brake pedal10. The motor1610may operate the pair of pumps1620by receiving power from a battery or the like.

The pair of pumps1620may pressurize the pressurized medium according to reciprocating movement of a piston (not shown) provided in the motor1610. The pumps1620receive the pressurized medium from the second connection line420connected to the sub-reservoir1100band pressurize the pressurized medium by operation of the motor1610to a hydraulic pressure level required for braking.

The pressurized medium whose hydraulic pressure is generated by any one pump1620of the pair of pumps1620may be transmitted to the first wheel cylinder21by the first auxiliary hydraulic flow path1631provided as a discharge side flow path of the pump1620. To this end, an inlet side end portion of the first auxiliary hydraulic flow path1631may be connected to the discharge side of the pump1620, and an outlet side end portion may be connected to the first wheel cylinder21, and the first support valve1631acontrolling the flow of the pressurized medium transmitted from the pump1620to the first wheel cylinder21is provided on the first auxiliary hydraulic flow path1631. The first support valve1631amay be provided as a normal closed type solenoid valve that operates to be opened when receiving an electrical signal from the electronic control unit in a normally closed state. When switched to the first fallback mode, the electronic control unit may open the first support valve1631aso that the hydraulic pressure of the pressurized medium discharged from the pump1620may be provided to the first wheel cylinder21.

The pressurized medium whose hydraulic pressure is generated by the other pump1620of the pair of pumps1620may be transmitted to the second wheel cylinder22by the second auxiliary hydraulic flow path1632provided as a discharge side flow path of the pump1620. To this end, an inlet side end portion of the second auxiliary hydraulic flow path1632may be connected to the discharge side of the pump1620, and an outlet side end portion may be connected to the second wheel cylinder22, and the second support valve1632acontrolling the flow of the pressurized medium transmitted from the pump1620to the second wheel cylinder22is provided on the second auxiliary hydraulic flow path1632. Like the first support valve1631a, the second support valve1632amay be provided as a normal closed type solenoid valve that operates to be opened when receiving an electrical signal from the electronic control unit in a normally closed state. When switched to the first fallback mode, the electronic control unit may open the second support valve1632aso that the hydraulic pressure of the pressurized medium discharged from the pump1620may be provided to the second wheel cylinder22.

The pressurized medium applied to the first wheel cylinder21may be discharged through the first auxiliary dump flow path1641. To this end, one side end portion of the first auxiliary dump flow path1641may be connected to the first wheel cylinder21or a downstream side of the first support valve1631aof the first auxiliary hydraulic flow path1631, and the other side end portion may be connected to the sub-reservoir1100bor connected to an inlet end side of the pump1620through the second connection line420, which will be described below. The first discharge valve1641acontrolling the flow of the pressurized medium discharged from the first wheel cylinder23is provided on the first auxiliary dump flow path1641. The first discharge valve1641amay be provided as a normal closed type solenoid valve that operates to be opened when receiving an electrical signal from the electronic control unit in a normally closed state.

The pressurized medium applied to the second wheel cylinder22may be discharged through the second auxiliary dump flow path1642. To this end, one side end portion of the second auxiliary dump flow path1642may be connected to the second wheel cylinder21or a downstream side of the second support valve1632aof the second auxiliary hydraulic flow path1632, and the other side end portion may be connected to the sub-reservoir1100bor connected to the inlet end side of the pump1620through the second connection line420, which will be described below. The second discharge valve1642acontrolling the flow of the pressurized medium discharged from the second wheel cylinder22is provided on the second auxiliary dump flow path1642. Like the first discharge valve1641a, the second discharge valve1642amay be provided as a normal closed type solenoid valve that operates to be opened when receiving an electrical signal from the electronic control unit in a normally closed state.

The connection line400is provided to hydraulically connect the first block100of the mechanical unit, the second block200of the electronic unit, and the emergency module300, which are disposed to be spaced apart from each other.

The connection line400may include the first connection line410connecting the integrated master cylinder1200of the mechanical unit and the first hydraulic circuit1510of the hydraulic control unit1400, the second connection line420connecting the hydraulic pressure auxiliary device1600of the emergency module300and the sub-reservoir1100bof the electronic unit, and the third connection line430connecting the main reservoir1100aof the mechanical unit and the sub-reservoir1100bof the electronic unit.

One end of the first connection line410may be connected to the second master chamber1230aof the integrated master cylinder1200, and the other end may be connected to the downstream or rear end sides of the first and second inlet valves1511aand1512aof the first hydraulic circuit1510.

The cut valve411is provided in the first connection line410so that the pressurized medium flow between the second master chamber1220aand1230aof the integrated master cylinder1200and the first hydraulic circuit1510may be controlled. The other end of the first connection line410may be branched to be connected between the rear end or downstream side of the first inlet valve1511aand the second inlet valve1512aand a front end of the hydraulic pressure auxiliary device1600, respectively.

The cut valve411may be provided as a normal open type solenoid valve that operates to be normally opened and to be closed when receiving a close signal from the electronic control unit.

As the cut valve411is controlled to a closed state in a normal operation mode that is a usual braking situation, the pressurized medium accommodated in the second master chamber1230ais not transmitted to the first hydraulic circuit1510despite a pedal force of the brake pedal10. In addition, as the cut valve411is controlled to the closed state in the normal operation mode, the hydraulic pressure of the pressurized medium provided from the hydraulic pressure supply device1300may not leak into the integrated master cylinder1200along the first connection line but be stably supplied toward the wheel cylinders21,22,23, and24.

However, as the cut valve411is put into an opened state in the second fallback mode that is switched on when the electronic unit and the emergency module are inoperative, the pressurized medium discharged from the first master chamber1220aand the second master chamber1230aof the integrated master cylinder1200may be supplied to the first and second wheel cylinders21and22through the first connection line410so that braking may be implemented.

The second connection line420is provided with one end connected to the sub-reservoir1100band the other end connected to the hydraulic pressure auxiliary device1600of the emergency module300. Specifically, as the other end of the second connection line420is connected to the inlet end of the pumps1620and the first and second auxiliary dump flow paths1641and1642, the pressurized medium may be supplied from the sub-reservoir1100bto the inlet end side of the pumps1620, or the pressurized medium may be discharged from the first and second auxiliary dump flow paths1641and1642to the sub-reservoir1100b.

The third connection line430may be provided with one end communicating with the main reservoir1100aand the other end communicating with the sub-reservoir1100b. When there is too much or too little pressurized medium in a reservoir on one side, the third connection line430may allow transmission of the pressurized medium between reservoirs and thus promote smooth supply of the pressurized medium to each component.

The first connection line410may be provided as a pipe having a predetermined strength, and the second connection line420and the third connection line430may be provided as hoses having elasticity. As the pressurized medium whose hydraulic pressure is generated from the second master chamber1230ais transmitted in the first connection line410, the first connection line410may be provided as a pipe with a strength capable of enduring the hydraulic pressure to promote the durability and performance of the product. Meanwhile, as the second connection line420and the third connection line430are provided to be connected to the main reservoir1100aor the sub-reservoir1100bhaving an internal pressure at an atmospheric pressure level, the pressurized medium without hydraulic pressure formed is transmitted. Accordingly, the second connection line420and the third connection line430may be provided as hoses having elasticity so that ease of installation may be promoted according to disposing positions of the first block100, the second block200, and the emergency module300. The first connection line410may be installed in a vehicle body by a fastening member (not shown) with a predetermined restoring force so that connectivity may be maintained despite an impact such as an accident of the vehicle or the like.

Hereinafter, an operation of the electronic brake system1according to the embodiment of the present invention will be described.

The operation of the electronic brake system1according to the embodiment of the present invention may be implemented in the normal operation mode in which the electronic brake system1normally operates without failure or abnormality of various devices and valves, in the first fallback mode in which the hydraulic pressure auxiliary device1600intervenes in an inoperative state of the hydraulic pressure supply device1300, and in the second fallback mode in which both the hydraulic supply device1300and the hydraulic pressure auxiliary device1600are inoperative.

First, the normal operation mode of the electronic brake system1according to the embodiment of the present invention will be described.

FIG.2is a hydraulic circuit diagram illustrating a state in which the normal operation mode of the electronic brake system1according to the embodiment of the present invention is performed. Referring toFIG.2, when the driver applies a pedal force to the brake pedal10for braking of the vehicle, the electronic control unit operates the motor of the hydraulic pressure supply device1300in one direction based on displacement information of the brake pedal10detected by the pedal displacement sensor11. A rotational force of the motor is transmitted to the hydraulic pressure supply unit by the power conversion unit, and the hydraulic piston1320of the hydraulic pressure supply unit operates to generate hydraulic pressure in the first pressure chamber1330or the second pressure chamber1340. The hydraulic pressure generated in the first pressure chamber1330or the second pressure chamber1340is transmitted to each of the first to fourth wheel cylinders21,22,23, and24through the hydraulic control unit1400, the first hydraulic circuit1510, and the second hydraulic circuit1520to generate a braking force.

In the normal operation mode, as the cut valve411provided in the first connection line410is switched to be closed, the pressurized medium of the integrated master cylinder1200is prevented from being transmitted to the wheel cylinders. In addition, the dump valve1810provided on the dump flow path1800is also switched to be closed. As the cut valve411and the dump valve1810are switched to be closed, the hydraulic pressure provided by the hydraulic pressure supply device1300is prevented from leaking into the integrated master cylinder1200and the sub-reservoir1100b, so that quick braking may be implemented.

In the normal operation mode, as the first to fourth inlet valves1511a,1511b,1521a, and1521bmaintain the opened state, the hydraulic pressure provided by the hydraulic pressure supply device1300may be smoothly transmitted to the first to fourth wheel cylinders21,22,23, and24, and as the first and second outlet valves1522aand1522bmaintain the closed state, the pressurized medium may be prevented from leaking into the sub-reservoir1100b.

Meanwhile, in the normal operation mode, when the driver applies a pedal force to the brake pedal10, as the cut valve411is closed, the second master chamber1230ais sealed. Accordingly, as the driver presses the brake pedal10, the first master piston1220moves forward and thus a displacement is generated, while the second master piston1230does not generate a displacement and thus compress the pedal simulator1240, so that an elastic restoring force by the compression of the pedal simulator1240may be provided to the driver as a pedal feeling. At this time, the pressurized medium accommodated in the first master chamber1220ais discharged to the main reservoir1100athrough the first main reservoir flow path1110a.

Since the normal operation mode is a state in which the hydraulic pressure supply device1300normally operates, the hydraulic pressure auxiliary device1600does not intervene, and the first and second isolation valves1651and1652maintain the opened state so that the hydraulic pressure of the pressurized medium supplied from the hydraulic pressure supply device1300may be smoothly provided to the first to fourth wheel cylinders21,22,23, and24.

Hereinafter, release of the normal operation mode of the electronic brake system1according to the embodiment of the present invention will be described.

FIG.3is a hydraulic circuit diagram illustrating a state in which the electronic brake system1according to the embodiment of the present invention releases the normal operation mode, and referring toFIG.3, when a pedal force applied to the brake pedal10is released, the electronic control unit operates the motor in the other direction based on displacement information of the brake pedal10detected by the pedal displacement sensor11. A rotational force of the motor is transmitted to the hydraulic pressure supply unit by the power conversion unit, and the hydraulic piston1320of the hydraulic pressure supply unit is operated. Thus, negative pressure may be generated in the first pressure chamber1330or the second pressure chamber1340, and the pressurized medium applied to the first to fourth wheel cylinders201,22,23, and24may be returned to the first pressure chamber1330or the second pressure chamber1340so that braking may be released.

In the normal operation mode, as the first to fourth inlet valves1511a,1511b,1521a, and1521bmaintain the opened state, the pressurized medium provided to the first to fourth wheel cylinders21,22,23, and24may be smoothly recovered to the hydraulic pressure supply device1300through the hydraulic control unit1400. In addition, in the normal operation mode, as the cut valve411and the dump valve1810are closed, the pressurized medium applied to the first to fourth wheel cylinders21,22,23, and24does not leak into the integrated master cylinder1200or the sub-reservoir1100bbut may be wholly recovered to the first pressure chamber1330or the second pressure chamber1340of the hydraulic pressure supply device1300. Meanwhile, the first and second outlet valves1522aand1522bmaintain the closed state, and when quicker removal of the pressurized medium applied to the third and fourth wheel cylinders23and24is required, the first and second outlet valves1522aand1522bmay be selectively opened.

Meanwhile, when the driver removes the pedal force on the brake pedal10, the first master piston1220is returned to an original position by the first piston spring1220band an elastic restoring force of the pedal simulator1240. As the volume of the first master chamber1220aincreases due to the return of the first master piston1220to the original position, the pressurized medium is supplied from the main reservoir1100ato the first master chamber1220athrough the main reservoir flow path1110aso that the inside of the first master chamber1220amay be filled with the pressurized medium again.

The electronic brake system1according to the embodiment of the present invention may be switched to the first fallback mode illustrated inFIGS.4and5when the hydraulic pressure supply device1300corresponds to an inoperative state such as a failure, a leakage of the pressurized medium, or the like.

FIG.4is a hydraulic circuit diagram illustrating a state in which the first fallback mode is performed when the hydraulic pressure supply device1300of the electronic brake system1according to the embodiment of the present invention is stopped. Referring toFIG.4, the electronic control unit is switched to the first fallback mode when it is determined that the hydraulic pressure supply device1300is inoperative due to a failure or the like.

In the first fallback mode, when the driver applies a pedal force to the brake pedal10, the electronic control unit operates the hydraulic pressure auxiliary device1600based on displacement information of the pedal brake pedal10detected by the pedal displacement sensor11. When entering the first fallback mode, the electronic control unit hydraulically isolates the first and second wheel cylinders21and22from the hydraulic pressure supply device1300by operating the first isolation valve1651and the second isolation valve1652to be closed.

The electronic control unit may operate the motor1610of the hydraulic pressure auxiliary device1600based on the displacement information of the pedal, and the pair of pumps1620may generate hydraulic pressure of the pressurized medium by the operation of the motor1610. The pressurized medium whose hydraulic pressure is generated by the pumps1620may be transmitted to the first and second wheel cylinders21and22through the first and second auxiliary hydraulic flow paths1631and1632, respectively, and at this time, the first and second support valves1631aand1632aprovided on the first and second auxiliary hydraulic flow paths1631and1632, respectively, are operated in the opened state. In addition, as the first and second discharge valves1641aand1642aprovided on the first and second auxiliary dump flow paths1641and1642, respectively, are controlled to the closed state, the hydraulic pressure of the pressurized medium generated by the pumps1620may be prevented from leaking the sub-reservoir1100bthrough the second connection line420. Besides, the electronic control unit may open the dump valve1810to stably control the behavior of the vehicle in the first fallback mode and thus discharge the pressurized medium applied to the third and fourth wheel cylinders23and24to the sub-reservoir1100bthrough the dump flow path1800.

Meanwhile, since the integrated master cylinder1200and the pedal simulation operation in the first fallback mode are the same as the above-described operation of the normal operation mode, in order to prevent redundant description, a description thereof will be omitted.

Hereinafter, release of the first fallback mode of the electronic brake system1according to the embodiment of the present invention will be described.

FIG.5is a hydraulic circuit diagram illustrating a state in which the electronic brake system1according to the embodiment of the present invention releases the first fallback mode, and referring toFIG.5, when the pedal displacement sensor11detects that the pedal force of the brake pedal10is released, the electronic control unit may switch the first and second support valves1631aand1632aprovided on the first and second auxiliary hydraulic flow paths1631and1632, respectively, to the closed state and thus prevent the pressurized medium from being transmitted from the motor1610and the pumps1620to the first and second wheel cylinders21and22. At the same time, as the first and second discharge valves1641aand1642aprovided on the first and second auxiliary dump flow paths1641and1642, respectively, are switched to the opened state, the pressurized medium applied to the first and second wheel cylinders21and22may be transmitted to the second connection line420and discharged to the sub-reservoir1100bor discharged to the inlet end side of the pumps1620, so that braking of the first and second wheel cylinders21and22may be released.

Herein, as the first and second isolation valves1651and1652still maintain the closed state, the pressurized medium applied to the first and second wheel cylinders21and22may be prevented from being introduced to the hydraulic pressure supply device1300.

Meanwhile, since the integrated master cylinder1200and the pedal simulation operation when the first fallback mode is released are the same as the above-described operation of the normal operation mode, in order to prevent redundant description, a description thereof will be omitted.

The electronic brake system1according to the embodiment of the present invention may be switched to the second fallback mode illustrated inFIGS.6and7when not only the hydraulic pressure supply device1300but also the hydraulic pressure auxiliary device1600corresponds to an inoperative state such as a failure, a leakage of the pressurized medium, or the like.

FIG.6is a hydraulic circuit diagram illustrating a state in which the second fallback mode is performed when the hydraulic pressure supply device1300and the hydraulic pressure auxiliary device1600of the electronic brake system1according to the embodiment of the present invention are stopped. Referring toFIG.6, the electronic control unit is switched to the second fallback mode when it is determined that the hydraulic pressure supply device1300and the hydraulic pressure auxiliary device1600are inoperative due to a failure or the like.

In the second fallback mode, each valve is controlled to an inoperative state. Herein, when the driver applies a pedal force to the brake pedal10, the first master piston1220connected to the brake pedal10moves forward so that a displacement is generated. In the inoperative state, as the cut valve411is provided in the opened state, the second master piston1230may also move forward due to the forward movement of the first master piston1220, and thus the pressurized medium accommodated in the second master chamber1230amay be transmitted to the first wheel cylinder21and the second wheel cylinder22of the first hydraulic circuit1510along the first connection line410to implement braking of the vehicle.

In the inoperative state, as the first and second isolation valves1651and1652of the hydraulic pressure auxiliary device1600maintain the opened state, the hydraulic pressure of the pressurized medium transmitted along the first connection line410in the second fallback mode may be stably transmitted toward the first and second wheel cylinders21and22.

Hereinafter, an operation of releasing the second fallback mode by the electronic brake system1according to the embodiment of the present invention will be described.

FIG.7is a hydraulic circuit diagram illustrating a state in which the electronic brake system1according to the embodiment of the present invention releases the second fallback mode, and referring toFIG.7, when the driver releases the pedal force applied to the brake pedal10, the first and second master pistons1220and1230, which have moved forward, are returned to the original positions by the first and second piston springs1220band1230band the elastic restoring force of the pedal simulator120. As the first and second master pistons1220and1230are returned to the original positions, negative pressure may be generated in each of the first and second master chambers1220aand1230a, and the pressurized medium applied to the first and second wheel cylinders21and22may be recovered to the second master chamber1230aalong the first connection line410, so that braking of the first and second wheel cylinders21and22may be released.