Electronic control brake system with piezoelectric actuator
The present invention relates to an electronic control brake system. The present invention is directed to an electronic control brake system in which an oil pressure created in a master cylinder is transferred to a wheel brake to apply a braking force thereto in response to the pedal depression or control of an electronic control unit. The electronic control brake system comprises a normal open solenoid valve for selectively switching on or off the oil pressure created in the master cylinder, and a piezoelectric actuator for regulating a magnitude of the oil pressure applied to the wheel brake through the solenoid valve. Thus, the electronic control brake system of the present invention can have a simplified structure enough to be easily manufactured, have a compact shape and perform the creation/removal of oil pressure in the wheel brake and the resultant precise braking force control only by adjusting the amount of electricity to be supplied thereto. Therefore, since a variety of functions ABS, TCS, ESP, EHB and EPB in which a precise braking control is required can be performed without additional components, there is an advantage in that the present invention has excellent applicability.
1 . An electronic control brake system in which an oil pressure created in a master cylinder is transferred to a wheel brake to apply a braking force thereto in response to pedal depression or control of an electronic control unit, said system comprising:
a normal open solenoid valve for selectively switching on or off the oil pressure created in the master cylinder; and
a piezoelectric actuator for regulating a magnitude of the oil pressure applied to the wheel brake through the solenoid valve.
2 . The electronic control brake system as claimed in claim 1 , wherein the piezoelectric actuator comprises:
a hollow cylinder connected to the normal open solenoid valve;
a piezoelectric element expanded or contracted as electricity is intermittently supplied thereto selectively according to a control of the electronic control unit; and
a piston moving upward and downward due to the expansion/contraction of the piezoelectric actuator to exert or remove the oil pressure on or from the interior of the cylinder.