Electro-hydraulic brake system

1. An electro-hydraulic brake system comprising:

a master cylinder to transmit brake oil;

a high-pressure accumulator to transmit brake oil independently of the master cylinder;

a first circuit connected to the master cylinder and the high-pressure accumulator;

a second circuit connected to the master cylinder and the first circuit;

a first wheel to be braked by the first circuit; and

a second wheel to be braked by the second circuit,

wherein the first circuit includes a first flow-rate control valve to control a flow rate of the brake oil transmitted from the high-pressure accumulator into the first circuit, and the second circuit includes a second flow-rate control valve to control a flow rate of the brake oil introduced into the second circuit,

wherein the first and second flow-rate control valves are arranged such that a flow path extending from an outlet of the first flow-rate control valve to an inlet of the second flow-rate control valve excludes the high-pressure accumulator.

2. The system according to claim 1 , further comprising:

a first backup path connecting the master cylinder and the first circuit to each other;

a second backup path connecting the master cylinder and the second circuit to each other;

a first mode switching valve to control connection between the first backup path and the master cylinder; and

a second mode switching valve to control connection between the second backup path and the master cylinder.

3. The system according to claim 2 , wherein the first mode switching valve, the second mode switching valve, the first flow-rate control valve and the second flow-rate control valve are arranged in a row, to control transmission of the brake oil to the wheels.

4. The system according to claim 3 , wherein:

during normal braking, the first mode switching valve and the second mode switching valve are kept in a closed state, and the first flow-rate control valve and the second flow-rate control valve transmit hydraulic pressure generated in the high-pressure accumulator to the first circuit and the second circuit; and

during emergency braking, the first mode switching valve and the second mode switching valve are kept in an open state, to transmit hydraulic pressure generated in the master cylinder to the first circuit and the second circuit.

5. The system according to claim 2 , further comprising a pressure sensor provided at an entrance side of the first mode switching valve to measure brake pedal pressure.

6. The system according to claim 1 , further comprising:

a first inlet path provided with the first flow-rate control valve and connecting the high- pressure accumulator and the first circuit to each other; and

a second inlet path provided with the second flow-rate control valve and connecting the first circuit and the second circuit to each other.

7. The system according to claim 6 , further comprising:

a first pressure sensor provided at an exit side of the first flow-rate control valve to measure pressure of oil introduced into the first circuit; and

a second pressure sensor provided at an exit side of the second flow-rate control valve to measure pressure of oil introduced into the second circuit.

8. The system according to claim 1 , wherein each of the first and second flow-rate control valves are two-way valves.

9. The system according to claim 1 , wherein the first circuit further includes a first inlet valve fluidly arranged between the first flow-rate control valve and the first wheel, and the second circuit further includes a second inlet valve fluidly arranged between the second flow-rate control valve and the second wheel.