Roller screw system

An electromechanical brake apparatus, comprising:

• a housing defining a mechanism cavity;
• a roller screw located at least partially within the mechanism cavity, the roller screw including
• a spindle including a helically threaded portion and defining a longitudinal axis about which the spindle rotates,
• a nut at least partially radially surrounding the helically threaded portion of the spindle, the nut including a helical thread on an interior lumen wall thereof, the nut being configured for longitudinal motion selectively in a first direction and in a second direction, opposite the first direction, with respect to the spindle,
• at least one non-helically grooved roller, interposed radially between the spindle and the nut, and
• a cage maintaining the at least one roller in position radially between the spindle and the nut, the cage supporting the at least one roller for rotational motion about a longitudinal axis of the at least one roller, the at least one roller maintaining a substantially constant longitudinal position with respect to the cage during operation of the roller screw system, the cage being configured to urge the spindle toward a radially centered position within the nut;
• and
• a brake pad, operatively connected to the nut for longitudinal driving thereby, the nut being moved, and responsively moving the brake pad, in the first and second directions in a duty cycle responsive to transmission of rotational motion from the spindle to the at least one roller, and transformation of rotational motion of the at least one roller to longitudinal motion of the nut;
• and
• a motor, operatively connected to the spindle to provide rotational motion thereto.