Patent Description:
Description of this section only provides the background information of the present invention without configuring the related art.

An electric hydraulic brake generates hydraulic pressure using an electric motor and generates braking force at each wheel cylinder by transmitting the hydraulic pressure to the wheel cylinders. An electric hydraulic brake makes it easy to individually control braking force that is generated at each wheel brake, and accordingly, it is possible to easily implement functions such as an Electronic Stability Control (ESC) System or an Anti-Lock Brake System (ABS).

ESC is for keeping the posture of a vehicle stable when the posture of the vehicle becomes unstable during driving. Factors that make the posture of a vehicle unstable are a slippery road condition due to rain, snow, sand, etc., motion inertia such as rapid zigzag driving, etc. An ESC system keeps the posture of a vehicle stable by controlling a brake and engine torque when the posture of the vehicle is dangerous.

Redundancy design of a brake system is required to prevent danger due to malfunction of a brake system that is electronically operated. For example, when the brake system of a vehicle electronically malfunctions, a driver can directly generate braking force in person by depressing a pedal using foot force. Alternatively, it is possible to configure a brake system in a <NUM>-box type and generate braking force using another brake system when one brake system malfunctions.

However, when a brake system is configured in a <NUM>-box type, there is a problem in that it is physically limited in terms of space to install two brake systems in an engine room. Further, there is another problem in that additional space and parts are needed to connect two controllers through a pipe.

Document <CIT> and <CIT>, on which the twopart form is based, disclose an electronic brake system that generates a brake force using an electrical signal corresponding to a displacement of a brake pedal. <CIT> discloses an electronic brake device that can reduce the number of valve operations during a braking process.

According to at least one embodiment, the present invention provides an electric hydraulic brake according to claim <NUM>. Said electric hydraulic brake including: a plurality of wheel brakes configured to supply braking force to wheels of a vehicle; a reservoir storing brake oil; a master cylinder connected to the reservoir and configured to generate hydraulic pressure in cooperation with a motor; a hydraulic circuit configured to selectively transmit the hydraulic pressure to the plurality of wheel brakes, the hydraulic circuit including a front wheel hydraulic circuit to transmit the hydraulic pressure to a pair of front wheel brakes, a rear wheel hydraulic circuit to transmit the hydraulic pressure to a pair of rear wheel brakes, and a plurality of solenoid valves; a first controller configured to control the motor, the front and read wheel hydraulic circuits and a rear wheel right electronic parking brake in accordance with braking input; and a second controller configured to control the motor, the front wheel hydraulic circuit and a rear wheel left electronic parking brake, wherein a braking force is generated by using only the front wheel hydraulic circuit and the rear wheel left electronic parking brake when the first controller malfunctions. Preferred embodiments of the present invention are laid down in the dependent claims.

An electric hydraulic brake according to an embodiment variant of the present invention can implement redundancy of a brake system of a vehicle by dually designing only a controller in one mechanical package.

The objects of the present invention are not limited to the objects described above and other objects will be clearly understood by those skilled in the art from the following description.

Hereinafter, some embodiment variants of the present invention will be described in detail with reference to the accompanying drawings. In the following description, like reference numerals preferably designate like elements, although the elements are shown in different drawings. Further, in the following description of some embodiment variants, a detailed description of related known components and functions when considered to obscure the subject of the present invention will be omitted for the purpose of clarity and for brevity.

Additionally, alphanumeric codes such as first, second, i), ii), (a), (b), etc., in numbering components are used solely for the purpose of differentiating one component from the other but not to imply or suggest the substances, the order, or sequence of the components. Throughout this specification, when parts "include" or "comprise" a component, they are meant to further include other components, not excluding thereof unless there is a particular description contrary thereto. The terms such as 'unit,' 'module,' and the like refer to one or more units for processing at least one function or operation, which may be implemented by hardware, software, or a combination thereof.

<FIG> is a hydraulic circuit diagram of an electric hydraulic brake according to an embodiment variant of the present invention.

Referring to <FIG>, an electric hydraulic brake <NUM> according to an embodiment variant of the present invention may include all or some of a master cylinder <NUM>, a reservoir <NUM>, a hydraulic circuit, and a controller. The controller may be an Electronic Control Unit (ECU). The controller includes a first controller <NUM> and a second controller <NUM>.

The master cylinder <NUM> may include all or some of a motor <NUM>, a ball screw, a piston <NUM>, a first chamber <NUM>, and a second chamber <NUM>.

The master cylinder <NUM> generates hydraulic pressure in cooperation with the motor <NUM>. When a driver strokes a brake pedal, the motor <NUM> is rotated by an electrical signal and the ball screw and the piston <NUM> linked with the motor <NUM> are moved forward, so hydraulic pressure can be generated in the master cylinder. When the brake pedal is depressed, the master cylinder can supply the hydraulic pressure to a plurality of wheel brakes w1, w2, w3, and w4. In this case, a forward movement direction means that the piston <NUM> is moved toward the first chamber <NUM> and a backward movement direction means that the piston <NUM> is moved toward the second chamber <NUM>.

The master cylinder <NUM> may have a dual structure of which the inside is divided into the first chamber <NUM> and the second chamber by the piston <NUM>. The motor <NUM> has a dual winding structure, and the first controller <NUM> and the second controller <NUM> each may control <NUM>% of the motor <NUM> under the assumption that the performance of the motor <NUM> is <NUM>%.

The plurality of wheel brakes w1, w2, w3, and w4 includes a first wheel brake w1 that brakes the front left wheel of a vehicle, a second wheel brake w2 that brakes the front right wheel of the vehicle, a third wheel brake w3 that brakes the rear left wheel of the vehicle, and a fourth wheel brake w4 that brakes the rear right wheel of the vehicle. The first to fourth wheel brakes w1 to w4 are formally defined for the convenience of description and the positions of the first to fourth wheel brakes w1 to w4 are not limited to the positions defined above.

The hydraulic circuit of the electric hydraulic brake <NUM> includes a front wheel hydraulic circuit and a rear wheel hydraulic circuit. The front wheel hydraulic circuit is configured to transmit hydraulic pressure to a pair of front wheel brakes w1 and w2. The rear wheel hydraulic circuit is configured to transmit hydraulic pressure to a pair of rear wheel brakes w3 and w4.

The front wheel hydraulic circuit may include all or some of a first main control valve <NUM>, a first main flow path <NUM>, inlet valves <NUM> and <NUM>, an inlet flow path, outlet valves <NUM> and <NUM>, and an outlet flow path.

The first main flow path <NUM> may be connected to the first chamber <NUM> of the master cylinder <NUM> via the first main control valve <NUM>. When the piston <NUM> is moved forward in accordance with a braking request, brake oil can be transmitted to the plurality of wheel brakes w1 to w4 from the first chamber <NUM> through the first main flow path <NUM>. The first main control valve <NUM> can adjust the hydraulic pressure that is transmitted from the first chamber <NUM> to the plurality of wheel brakes w1 to w4. The first main control valve <NUM> may be a normal open type solenoid valve that is normally open and operates to close when receiving a closing signal from the controller (ECU).

The front wheel hydraulic circuit may include one or more inlet flow paths diverging from the first main flow path <NUM> to transmit hydraulic pressure to the front wheel brakes w1 and w2, respectively. The inlet valves <NUM> and <NUM> are installed in the inlet flow path and can control the hydraulic pressure, which is transmitted to the front wheel brakes w1 and w2, respectively, when braking is required.

The front wheel hydraulic circuit may include one or more outlet flow paths connecting the front wheel brakes w1 and w2 to the reservoir <NUM>, respectively. The outlet valves <NUM> and <NUM> are installed in the outlet flow path and can control the hydraulic pressure, which is discharged from the front wheel brakes w1 and w2, respectively, when braking is stopped.

The rear wheel hydraulic circuit may include all or some of a second main control valve <NUM>, a second main flow path <NUM>, inlet valves <NUM> and <NUM>, an inlet flow path, outlet valves <NUM> and <NUM>, and an outlet flow path.

The second main flow path <NUM> may be connected to the second chamber <NUM> of the master cylinder <NUM> via the second main control valve <NUM>. When the piston <NUM> is moved backward in accordance with a braking request, brake oil can be transmitted to the plurality of wheel brakes w1 to s4 from the second chamber <NUM> through the second main flow path <NUM>. The second main control valve <NUM> can adjust the hydraulic pressure that is transmitted from the second chamber <NUM> to the plurality of wheel brakes w1 to w4. The second main control valve <NUM> may be a normal open type solenoid valve that is normally open and operates to close when receiving a closing signal from a controller.

The rear wheel hydraulic circuit may include one or more inlet flow paths diverging from the second main flow path <NUM> to transmit hydraulic pressure to the rear wheel brakes w3 and w4, respectively. The inlet valves <NUM> and <NUM> are installed in the inlet flow path and can control the hydraulic pressure, which is transmitted to the front wheel brakes w3 and w4, respectively, when braking is required.

The rear wheel hydraulic circuit may include one or more outlet flow paths connecting the front wheel brakes w3 and w4 to the reservoir <NUM>, respectively. The outlet valves <NUM> and <NUM> are installed in the outlet flow path and can control the hydraulic pressure, which is discharged from the front wheel brakes w3 and w4, respectively, when braking is stopped.

The inlet valves <NUM> to <NUM> are disposed at the upstream side of the wheel brakes w1 to w4 and may be normal open type solenoid valves that are normally open and operate to close when receiving a closing signal from a controller. The outlet valves <NUM> to <NUM> are disposed at the downstream side of the inlet valves <NUM> to <NUM> and may be normal closed type solenoid valves that are normally closed and operate to open when receiving an opening signal from a controller.

The electric hydraulic brake <NUM> according to an embodiment variant of the present invention may further include a fixing valve <NUM>, a mixing flow path, and a recovery valve <NUM>.

The mixing valve <NUM> may be installed in a mixing flow path connecting the front wheel hydraulic circuit and the rear wheel hydraulic circuit. The mixing valve <NUM> can control hydraulic pressure that is transmitted between the front wheel hydraulic circuit and the rear wheel hydraulic circuit. The mixing valve <NUM> may be a Low pressure Switching Valve (LSV). The mixing valve <NUM> may be a normal closed type solenoid valve that is normally closed and operates to open when receiving an opening signal.

The electric hydraulic brake <NUM> according to an embodiment variant of the present invention may implement redundancy by dually configuring the first controller <NUM> and the second controller <NUM>. That is, by dually installing only controller in one mechanical package, even if one controller malfunctions, the other controller can secure braking force of the electric hydraulic brake <NUM>.

The first controller <NUM> and the second controller <NUM> each may include a <NUM>-pin connector and a Micro Controller Unit (MCU). A plurality of solenoid valves of the front wheel hydraulic circuit may be connected with the first controller <NUM> and the second controller <NUM>. That is, even if the first controller <NUM> malfunctions, the front wheel hydraulic circuit can perform control using the second controller <NUM>. A plurality of solenoid valves of the rear wheel hydraulic circuit may be connected with the first controller <NUM>.

In a normal state, the first controller <NUM> and the second controller <NUM> can control the electric hydraulic brake <NUM> by cooperating with each other. When the first controller <NUM> malfunctions, the second controller <NUM> can control a Conventional Brake System (CBS). When the second controller <NUM> malfunctions, the first controller <NUM> can control an Electronic Parking Brake (EPB).

<FIG> is a table showing a control relationship between first and second controllers and a plurality of solenoid valves of the electric hydraulic brake according to an embodiment variant of the present invention.

Referring to <FIG>, the first controller <NUM> controls the front wheel hydraulic circuit and the rear wheel hydraulic circuit. The first controller <NUM> can control the first main controller <NUM>, the second main controller <NUM>, the inlet valves <NUM> to <NUM>, the outlet valve <NUM> to <NUM>, the mixing valve <NUM>, the recovery valve <NUM>, the motor <NUM>, the pedal sensor <NUM>, and the rear wheel right EPB.

The second controller <NUM> controls the front wheel hydraulic circuit. The second controller <NUM> can control the first main controller <NUM>, the front wheel inlet valves <NUM> and <NUM>, the front wheel outlet valve <NUM> and <NUM>, the motor <NUM>, the pedal sensor <NUM>, and the rear wheel left EPB. The first controller <NUM> and the second controller <NUM> can control the hydraulic circuits by cooperating with each other through communication in real time.

The pedal sensor <NUM> may include two channels and can communicate with the first controller <NUM> and the second controller <NUM>. The pedal sensor <NUM> may be positioned in the front wheel hydraulic circuit. However, the position of the pedal sensor <NUM> is not limited to the position described above as an embodiment variant.

The first main controller <NUM>, the front wheel inlet valves <NUM> and <NUM>, and the front wheel outlet valve <NUM> and <NUM> that are connected with the second controller <NUM> can be controlled using the second controller <NUM> even if the first controller <NUM> malfunctions. A control method when the first controller <NUM> or the second controller <NUM> malfunctions.

<FIG> is a hydraulic circuit diagram showing the flow of brake oil in a normal state of an electric hydraulic brake according to an embodiment variant of the present invention.

Referring to <FIG>, when the motor <NUM> and the ball screw of the master cylinder <NUM> malfunction, the electric hydraulic brake <NUM> can use the auxiliary actuator <NUM>. The auxiliary actuator <NUM> can generate hydraulic pressure using the pump unit by operating the second motor <NUM>.

When a braking request is generated, the first controller <NUM> and the second controller <NUM> rotate the motor <NUM>, and the ball screw and the piston <NUM> that are linked with the motor <NUM> are moved forward, so hydraulic pressure is generated in the master cylinder <NUM>. When the piston <NUM> is moved forward, the hydraulic pressure generated in the master cylinder <NUM> can be transmitted to the plurality of wheel brakes w1, w2, w3, and w4 via the first main control valve <NUM>, the plurality of inlet valves <NUM> to <NUM>, and the mixing valve <NUM>.

When a braking request is generated, the first controller <NUM> can control the second main control valve <NUM> and the mixing valve <NUM>. The first controller <NUM> can close the second main control valve <NUM> by transmitting a closing signal to the second main control valve <NUM>. The first controller <NUM> can open the mixing valve <NUM> by transmitting an opening signal to the mixing valve <NUM>.

Referring to <FIG>, when the electric hydraulic brake <NUM> does not malfunction, the first controller <NUM> can control the second main control valve <NUM> with the brake pedal released. The first controller <NUM> can remove residual pressure by opening and then closing again the second main control valve <NUM>. Hydraulic pressure can be transmitted to the reservoir <NUM> through the outlet flow path with the brake pedal released.

<FIG> is a hydraulic circuit diagram showing the flow of brake oil when there is malfunction in a rear wheel hydraulic circuit of the electric hydraulic brake according to an embodiment variant of the present invention.

When the rear wheel hydraulic circuit malfunctions, the first controller <NUM> can the mixing valve <NUM>. The first controller <NUM> can close the mixing valve <NUM> by transmitting a closing signal to the mixing valve <NUM>.

Referring to <FIG>, when the rear wheel hydraulic circuit malfunctions, the electric hydraulic brake <NUM> can generate braking force using only the front wheel hydraulic circuit by closing the mixing valve <NUM>. Further, the first controller <NUM> and the second controller <NUM> can remove residual pressure by controlling the front wheel outlet valves <NUM> and <NUM> with the brake pedal released.

When the rear wheel hydraulic circuit malfunctions, the electric hydraulic brake <NUM> can generate braking force using only the front wheel hydraulic circuit and the EPB. Accordingly, the electric hydraulic brake <NUM> can show performance of about <NUM>% in comparison the normal state. The functions of an Electronic Stability Control System (ESC) and an Anti-Lock Brake System (ABS) of the electric hydraulic brake <NUM> can be converted into a degraded mode in comparison to the normal state. Further, it is possible to perform cooperative control with steering to secure stability of a vehicle.

<FIG> is a hydraulic circuit diagram showing the flow of brake oil when there is malfunction in a front wheel hydraulic circuit of the electric hydraulic brake according to an embodiment variant of the present invention.

When the front wheel hydraulic circuit malfunctions, the first controller <NUM> can control the first main control valve <NUM> and the second main control valve <NUM>. The first controller <NUM> can close the first main control valve <NUM> by transmitting a closing signal to the first main control valve <NUM>. The first controller <NUM> can open the second main control valve <NUM> by transmitting an opening signal to the second main control valve <NUM>.

Referring to <FIG>, when the front wheel hydraulic circuit malfunctions, the electric hydraulic brake <NUM> can generate braking force using only the rear wheel hydraulic circuit by closing the first main control valve <NUM> and opening the second main control valve <NUM>. Further, the first controller <NUM> can remove residual pressure by controlling the recovery valve <NUM> with the brake pedal released.

When the front wheel hydraulic circuit malfunctions, the electric hydraulic brake <NUM> can generate braking force using only the rear wheel hydraulic circuit and the EPB. Accordingly, the electric hydraulic brake <NUM> can show performance of about <NUM> % in comparison the normal state. The functions of the electric hydraulic brake <NUM>, such as an ESC and an ABS, can also be converted into a degraded mode in comparison to the normal state. Further, it is possible to perform cooperative control with steering to secure stability of a vehicle.

<FIG> is a hydraulic circuit diagram showing the flow of brake oil when there is malfunction in a second controller of the electric hydraulic brake according to an embodiment variant of the present invention.

Referring to <FIG>, even if the second controller <NUM> malfunctions, it is possible to transmit hydraulic pressure to the plurality of wheel brakes w1, w2, w3, and w4 in the same way as the normal state(Referring to <FIG>).

When a braking request is generated, the first controller <NUM> rotates the first motor <NUM>, and the ball screw and the piston <NUM> that are linked with the first motor <NUM> are moved forward, so hydraulic pressure is generated in the master cylinder <NUM>. When the piston <NUM> is moved forward, the hydraulic pressure generated in the master cylinder <NUM> can be transmitted to the plurality of wheel brakes w1, w2, w3, and w4 via the first main control valve <NUM>, the plurality of inlet valves <NUM> to <NUM>, and the mixing valve <NUM>.

When a braking request is generated, the first controller <NUM> can control the second main control valve <NUM> and the mixing valve <NUM>. The first controller <NUM> can close the second main control valve <NUM> by transmitting a closing signal to the second main control valve <NUM>. The first controller <NUM> can open the mixing valve <NUM> by transmitting an opening signal to the mixing valve <NUM>. The situation in which the brake pedal is released in the same as the case of <FIG>. That is, even if the second controller <NUM> malfunctions, it is possible to control a plurality of solenoid valves using the first controller <NUM> in the same was as the normal state.

When the second controller <NUM> malfunctions, the rear wheel left EPB that is controlled by the second controller <NUM> cannot be used. Further, since the first controller <NUM> and the second controller <NUM> control the motor <NUM> in the ratio of <NUM>:<NUM>, the output of the first motor <NUM> may be limited to <NUM>% of the normal state.

<FIG> is a hydraulic circuit diagram showing the flow of brake oil when there is malfunction in a first controller of the electric hydraulic brake according to an embodiment variant of the present invention.

Referring to <FIG>, according to the present invention, when the first controller <NUM> malfunctions, the electric hydraulic brake <NUM> generates braking force using only the front wheel hydraulic circuit.

Furthermore according to the present invention, when the first controller <NUM> malfunctions, the electric hydraulic brake <NUM> generates braking force using only the front wheel hydraulic circuit and the rear wheel left EPB. Accordingly, the electric hydraulic brake <NUM> can show performance of about <NUM>% in comparison the normal state. The functions of the electric hydraulic brake <NUM>, such as an ESC and an ABS, can also be converted into a degraded mode in comparison to the normal state. Further, it is possible to perform cooperative control with steering to secure stability of a vehicle.

Claim 1:
An electric hydraulic brake (<NUM>) comprising:
a plurality of wheel brakes (w1, w2, w3, w4) configured to supply braking force to wheels of a vehicle;
a reservoir (<NUM>) storing brake oil;
a master cylinder (<NUM>) connected to the reservoir (<NUM>) and configured to generate hydraulic pressure in cooperation with a motor (<NUM>);
a hydraulic circuit configured to selectively transmit the hydraulic pressure to the plurality of wheel brakes (w1, w2, w3, w4), the hydraulic circuit including a front wheel hydraulic circuit to transmit the hydraulic pressure to a pair of front wheel brakes (w1, w2), a rear wheel hydraulic circuit to transmit the hydraulic pressure to a pair of rear wheel brakes (w3, w4), and a plurality of solenoid valves;
a first controller (<NUM>) configured to control the motor (<NUM>), the front and rear wheel hydraulic circuits and a rear wheel right electronic parking brake in accordance with braking input;
and
a second controller (<NUM>) configured to control the motor (<NUM>), the front wheel hydraulic circuit and a rear wheel left electronic parking brake, when the first controller (<NUM>) malfunctions, characterized in that the second controller is configured such that a braking force is generated by using only the front wheel hydraulic circuit and the rear wheel left electronic parking brake when the first controller (<NUM>) malfunctions.