Patent ID: 8863919

Claim:
An electric parking brake system comprising: a drum ( 1 ) that s rotated along with a vehicle wheel; first and second brake shoes ( 2 and 3 ) installed in both sides of the drum to apply brake force to the drum; an operating lever ( 5 ) that supports the two brake shoes and pushes the two brake shoes against an inner surface of the drum when a pivoting lever ( 8 ) is pulled; a motor ( 110 ) to generate drive power required to drive the pivoting lever; a cycloid speed reducer ( 120 ) connected to a rotating shaft ( 111 ) of the motor to amplify the drive power; a spindle member ( 130 ) rotatably connected to the cycloid speed reducer, the spindle member having a male screw portion ( 131 a ); and a nut member ( 140 ) having a coupling hole at one end thereof in which a female screw portion ( 141 a ) is screwed to the male screw portion of the spindle member in a rectilinear reciprocal manner and the other end of the nut member comes into contact with a lever pin and is provided with an inclined portion, wherein the nut member is moved in a longitudinal direction of the spindle member and supports an end of the pivoting lever, and the lever pin rotatably installed to the pivoting lever slides along the inclined portion.