Abstract: Direct drive electromechanical rotary-to-linear actuators include one or more electric motors mounted in a housing. Each motor includes a stator and a rotor. The motor drives a planetary drive mechanism that includes an elongated central shaft having one or more helical threads on an external surface coupled to the rotor for conjoint rotation. A planetary nut having helical threads on an internal surface is disposed concentric to the shaft, and a plurality of planetary rollers are disposed concentrically between the shaft and the planetary nut. Each of the rollers has a helical thread on an external surface that is complementary to and in engagement with a thread of the shaft and a thread of the nut. Rotation of the rotor is converted with mechanical advantage into linear movement of the planetary nut. The actuators provide backlash-free operation, higher stiffnesses, slew rates and frequency responses, and better overall efficiency.

Abstract: Direct drive electromechanical rotary-to-linear actuators include one or more electric motors mounted in a housing. Each motor includes a stator and a rotor. The motor drives a planetary drive mechanism that includes an elongated central shaft having one or more helical threads on an external surface coupled to the rotor for conjoint rotation. A planetary nut having helical threads on an internal surface is disposed concentric to the shaft, and a plurality of planetary rollers are disposed concentrically between the shaft and the planetary nut. Each of the rollers has a helical thread on an external surface that is complementary to and in engagement with a thread of the shaft and a thread of the nut. Rotation of the rotor is converted with mechanical advantage into linear movement of the planetary nut. The actuators provide backlash-free operation, higher stiffnesses, slew rates and frequency responses, and better overall efficiency.

Abstract: An internal combustion engine includes(a) a pair of opposed cylinders and pistons reciprocating therein,(b) power and return rollers carried by each of the pistons to reciprocate therewith during piston travel,(c) a power output shaft having an integral and external driven cam located to be driven in rotation by the power rollers in response to power stroke travel of the pistons, the shaft having an axis of rotation,(d) a flange integral with the output shaft and having an internal cam track located to be engaged by the return rollers in response to return stroke travel of the pistons,(e) said power and return rollers having parallel axes of rotation, the return roller axes located closer to the shaft axis than the power roller axes.