Electromechanical brake and operation method thereof

An electromechanical brake comprising:

• a piston provided to be movable forward and backward to press a brake pad toward a brake disc rotating together with a wheel;
• a power conversion unit comprising a spindle provided to rotate by receiving a driving force from an actuator, and a nut connected to the spindle to move forward or backward by rotation of the spindle in a first direction or a second direction to move the piston forward and backward;
• a position adjusting unit comprising an adjusting screw provided on the outside of the nut to rotate together with the nut, a first screw thread formed on an outer circumferential surface of the adjusting screw, a second screw thread formed on an inner circumferential surface of the piston to be engaged with the first screw thread, and an adjuster provided between the spindle and the nut to rotate the nut and the adjusting screw in the first direction or the second direction by rotation of the spindle to move a relative position of the piston with respect to the power conversion unit forward or backward;
• and
• an electronic control unit provided to control an operation of the actuator,
• wherein the electronic control unit controls the actuator to adjust a distance d between the brake disc and the brake pad.