ELECTROMECHANICAL DISC BRAKE APPARATUS

1 . An electromechanical disc brake apparatus in which a pair of frictional pads presses a circular plate shaped disc that is rotated along with a vehicle wheel for braking, the apparatus comprising:

a carrier secured to a vehicle body, wherein a pair of frictional pads, which are configured to come into frictional contact with the disc, is reciprocally mounted to the carrier;

a caliper housing having a guide rod to slidably couple the caliper housing to the carrier and a cylinder in which a piston to press any one of the pair of frictional pads against the disc is installed;

a drive unit secured to the carrier, wherein the drive unit includes a motor and a decelerator to generate drive force; and

a power conversion unit installed to the caliper housing to convert the drive force transmitted from the drive unit into rectilinear reciprocation of the piston.

2 . The apparatus according to claim 1 , wherein the power conversion unit includes a screw-shaft having a predetermined length, the screw-shaft being provided at an outer peripheral surface of one end portion thereof with threads so as to be fastened to the piston.

3 . The apparatus according to claim 2 , wherein the decelerator includes:

a first gear installed to a drive shaft of the motor; and

a second gear engaged with the first gear, a center portion of the second gear being connected to the other end portion of the screw-shaft to transmit power generated from the drive shaft to the screw-shaft after reducing revolutions per minute of the drive shaft.

4 . The apparatus according to claim 3 , wherein the first gear and the second gear are kept in an engaged state even if axial displacement occurs.

5 . The apparatus according to claim 4 , wherein any one of the first and second gears has a greater thickness.

6 . The apparatus according to any one of claims 1 to 5 , further comprising a fastening member to secure the drive unit to the carrier.