Patent ID: 8047339

Claim:
A caliper attaching type electrical parking brake in a vehicle, comprising: a main housing that contains a motor and power assembly; an electronic parking brake control unit that controls driving of the vehicle and generates a control signal for implementing parking by receiving a signal of an operation button; the motor being driven by a control signal of the electronic parking brake control unit; the power assembly comprising: a decelerator having a driving gear, a gear wheel, and a external ring gear, the external ring gear having a rotational axis that is parallel to a rotational axis of the gear wheel and a side surface that contacts a side surface of the gear wheel, the rotational axis of the gear wheel being parallel to a rotational axis of the driving gear and the side surface of the gear wheel contacts a side surface of the driving gear, and the driving gear receiving a rotation force of a motor rotating in a forward or reverse direction depending on a control of the electronic parking brake control unit, and an axial force generating gear assembly is arranged inside the external ring gear to penetrate the external ring gear in the rotational axis direction of the external ring gear, the axial force generating gear assembly including: an internal ring gear press-fit in the inside of the external ring gear, a planetary gear contacting an outer portion of the internal ring gear and arranged to penetrate the internal ring gear in a rotational axis direction of the internal ring gear, a fixed sun gear having one end fixed to the main housing so as not to rotate while contacting an outer portion of the planetary gear, an output sun gear generating output torque by rotating with the planetary gear, and a thrust bearing positioned at a front end of the planetary gear; the axial force generating gear assembly generating power in an axial direction to presses to press a pad toward a wheel disk; a linear movement unit having a screw shaft configured to move forward, backward, and linearly by receiving the output torque generated by the sun gear; and a caliper installed to cover the wheel disk mounted on a wheel and implementing a parking braking state of the vehicle as a piston presses the pad with a shaft-direction pressing force applied by the screw shaft and a nut of the linear movement unit to restrict the wheel disk.