Actuator assembly with preloaded ball screws

摘要

An actuator assembly includes a first motor having a first transmission mechanism, a second motor having a second transmission mechanism, and a drive shaft operatively coupled to the first transmission mechanism of the first motor and the second transmission mechanism of the second motor. The actuator assembly includes a torque application system disposed in operative communication with the first motor and the second motor, the torque application system configured to direct an application of a translation torque and a preload torque between the first motor and the first transmission mechanism and between the second motor and the second transmission mechanism.

主权项

1. An actuator assembly that generates an axial force between a sprung mass and an unsprung mass, comprising:
a threaded drive shaft that lies along a longitudinal axis and has first and second ends, the first end connected to one of the sprung mass and the unsprung mass; a housing that is connected to the other of the sprung mass and the unsprung mass, where the second end of the shaft is located within the interior of the housing such that the housing extends beyond the second end of the shaft; a first rotary motor that is carried within the housing; a first transmission mechanism comprising a first ball nut with a set of balls that are engaged with a first threaded portion of the drive shaft, the first ball nut configured to be rotated by the first motor in first and second rotational directions about the drive shaft longitudinal axis and thereby cause relative translation of the shaft and the housing in first and second translational directions along the longitudinal axis, wherein rotation of the first ball nut in the first rotational direction causes relative translation in the first translational direction, and rotation of the first ball nut in the second rotational direction causes relative translation in the second translational direction; a second rotary motor that is carried within the housing; a second transmission mechanism comprising a second ball nut that is spaced from the first ball nut and that has a set of balls that are engaged with a second threaded portion of the drive shaft, the second ball nut configured to be rotated by the second motor in the first and second rotational directions and thereby cause relative translation of the shaft and the housing in the first and second translational directions, wherein rotation of the second ball nut in the second rotational direction causes relative translation in the first translational direction, and rotation of the second ball nut in the first rotational direction causes relative translation in the second translational direction; and a torque application system disposed in operative communication with the first motor and the second motor, the torque application system configured to direct an application of a translation torque and a ball nut preload torque between the first transmission mechanism and the drive shaft and between the second transmission mechanism and the drive shaft; wherein the torque application system is configured to independently rotate the first and second motors in both rotational directions to direct the translational torques and the ball nut preload torques between the first and second transmission mechanisms and the drive shaft; wherein rotation of the motors in opposite directions causes relative translation of the shaft and the housing in a single translational direction; wherein rotation of the motors in the same direction causes ball nut preload torques with translational forces in opposite translational directions; wherein the torque application system comprises a controller disposed in electrical communication with the first motor and with the second motor, the controller configured to:
(i) generate a first drive signal as a sum of a translation torque control signal and a preload torque control signal;(ii) generate a second drive signal as a difference between the translation torque control signal and the preload torque control signal, the second drive signal distinct from the first drive signal;(iii) transmit the first drive signal to the first motor to generate at least one of the translation torque and the preload torque between the first transmission mechanism and the drive shaft; and(iv) transmit the second drive signal to the second motor to generate at least one of the translation torque and the preload torque between the second transmission mechanism and the drive shaft.