Electronic disc brake

An electronic disc brake comprising:

• a disc configured to be rotated with a wheel;
• a caliper housing configured to operate pad plates installed at both sides of the disc;
• and
• an actuator including:
• a piston disposed in the caliper housing and configured to press the pad plates to bring the pad plates into contact with the disc;
• a spindle rotatably installed in the caliper housing to move the piston forward and backward;
• a motor configured to rotate the spindle;
• and
• a speed reduction apparatus configured to transmit a rotational force of the motor to the spindle,
• wherein the speed reduction apparatus includes:
• a power connecting unit connected to the motor;
• a bracket disposed above the motor and configured to support the power connecting unit;
• a speed reduction gear unit having gear teeth and configured to sequentially connect the power connecting unit and the spindle;
• and
• a housing configured to accommodate the motor, and
• wherein the housing includes a speed reduction gear installation portion therein having gear teeth to be engaged with the gear teeth of the speed reduction gear unit,
• wherein the power connecting unit includes:
• a slave helical gear disposed at a first end of the power connecting unit and engaged with a master helical gear of the motor;
• a worm shaft gear connected to the speed reduction gear unit;
• and
• a bearing disposed at a second end of the power connecting unit, the bearing configured to support the power connecting unit and to reduce vibration.