Electronic disc brake

Abstract

Disclosed is an electronic disc brake. The electronic disc brake includes a disc configured to rotate with vehicle wheels, a caliper housing configured to operate pad plates installed at both sides of the disc, and an actuator having a piston provided inside the caliper housing to press the pad plates to adhere the pad plates to the disc, a spindle rotatably installed at the caliper housing to reciprocate the piston, an electric motor configured to rotate the spindle, and a decelerator configured to transmit a rotational force of the electric motor to the spindle. The decelerator includes a power connection unit connected to the electric motor, planetary gear units configured to connect the power connection unit to the spindle, and a center pin configured to pass through the power connection unit and the planetary gear units. The power connection unit includes a driving gear provided at a shaft of the electric motor and a driven gear connected to the planetary gear units. The planetary gear units each include a sun gear, a plurality of planetary gears engaged to an outer portion of the sun gear, a ring gear which is an internal gear configured to accommodate the planetary gears, a carrier installed to rotatably support the planetary gears and coaxially rotate with the sun gear and configured to and to output a rotational power, and an output shaft provided on the carrier and coupled to the spindle. The center pin has one end press-fitted and fixed to the output shaft.