electromechanical dry brake caliper

An electromechanical dry brake caliper; a planetary roller lead screw assembly is installed within a cylinder bore of the brake caliper assembly, and a motor and a reduction gear are connected to the planetary roller lead screw assembly; the planetary roller lead screw assembly comprises a lead screw, a nut, and rollers mounted between the lead screw and nut, the rollers are installed on a cage positioned between the lead screw and nut, with a torsion spring installed between the cage and nut; the nut has a first anti-rotation projection, and the cage has a second anti-rotation projection matching the first anti-rotation projection, elastic force of the torsion spring causes a side of the first anti-rotation projection on the nut to be in contact with a side of the second anti-rotation projection on the cage, at which time the rollers and the cage are in their initial positions.