Electronic brake device
The present disclosure provides an electronic hydraulic brake system that can appropriately provide redundancy braking force, that is, an electronic hydraulic brake system that provides a so-called redundancy function, in the situation in which a driver does not drive or gives less attention to driving such as autonomous driving or smart cruise control and a main braking device malfunctions.
1 . An electronic brake configured to generate a braking pressure for braking a vehicle electronically, without master cylinder hydraulics, the electronic brake comprising:
a plurality of wheel brake units configured to supply a braking force to a plurality of wheels of a vehicle;
a main braking device comprising a main electronic braking motor configured to generate a first brake oil pressure;
a secondary braking device comprising a secondary electronic braking motor configured to generate a second brake oil pressure;
a hydraulic circuit valve device configured to receive the first brake oil pressure from the main braking device and the second oil pressure from the secondary braking device and to selectively transmit, to the plurality of wheel brake units, the first or second brake oil pressure;
a main controller configured to control the main braking motor based on a braking input indicated by a braking signal; and
an assistant controller configured to:
control the secondary braking motor based on the braking input indicated by the braking signal; and
control the hydraulic circuit valve device to transmit the second brake oil pressure to a portion of the plurality of wheel brake units when the main controller or the main braking device malfunctions,
wherein:
the electronic brake further comprises a pedal simulator connected to a brake pedal that is configured to generate the braking signal based on a magnitude of a driver's force used to press the brake pedal of the vehicle, and
the pedal simulator and the pedal are separated from hydraulics of the electronic brake,
the main braking device has a double-acting piston-piston structure including a piston disposed in an internal space of the main braking device and two hydraulic pressure chambers separated by the piston,
the secondary braking device comprises an oil pump,
a second main braking valve is disposed on a hydraulic path between a reservoir and a forward chamber of the two hydraulic pressure chambers, the forward chamber being positioned in front of the piston of the main braking device,
the second main braking valve is configured to selectively transmit a working fluid from the secondary braking device to the portion of the plurality of wheel brake units depending on whether the second main braking valve is open or closed, and
when the hydraulic pressure at the plurality of wheel brake units is decreased and the second main braking valve is opened, the working fluid is transmitted from the forward chamber to the reservoir via the secondary braking device.
2 . The electronic brake of claim 1 , wherein, when one of the main controller and the main braking device malfunctions:
the secondary braking motor is configured to operate based on a second motor control signal generated by the assistant controller,
the secondary braking device is configured to transmit a hydraulic pressure to one or more wheel brake units of a first portion of the plurality of wheel brake units, and
the assistant controller is configured to control, using an electronic parking brake coupled to one or more wheel brake units of a second portion of the plurality of wheel brake units, a braking force provided to the wheel brake units of the second portion.
3 . The electronic brake of claim 1 , further comprising first and second assistant braking valves disposed in parallel with each other between the second main braking valve and the reservoir and configured to adjust the hydraulic pressure at the portion of the plurality of wheel brake units.