Ball screw actuator including a compliant ball screw stop

摘要

An actuator includes a ball nut, a ball screw, and a ball screw stop. The ball nut is adapted to receive an input torque and in response rotates and supplies a drive force. The ball screw extends through the ball nut and has a first end and a second end. The ball screw receives the drive force from the ball nut and in response selectively translates between a retract position and a extend position. The ball screw stop is mounted on the ball screw proximate the first end to translate therewith. The ball screw stop engages the ball nut when the ball screw is in the extend position, translates, with compliance, a predetermined distance toward the first end upon engaging the ball nut, and prevents further rotation of the ball screw upon translating the predetermined distance.

主权项

1. A method of establishing a relationship between motor current and reaction force for an electromechanical actuator (EMA) that is driven by a motor, wherein the EMA is a ball screw actuator that includes a ball nut and a ball screw, the method comprising the steps of:
providing a stop mechanism in the EMA that exhibits a predetermined force versus displacement characteristic; supplying current to the motor so that the stop mechanism is engaged and is displaced a predetermined distance thereby supplying a reaction force; measuring motor current while the stop mechanism is engaged; and determining the relationship between motor current and reaction force, wherein the step of providing the stop mechanism comprises:
mounting a ball screw stop on the ball screw proximate a first end thereof, and that is configured to:
(i) engage the ball nut when the ball screw is in an extend position,(ii) translate, with compliance, a predetermined distance toward the first end upon engaging the ball nut, and(iii) prevent further rotation of the ball screw upon translating the predetermined distance.