A ball screw assembly includes a guider, an open nut, an open shield, a first circulator, a second circulator, and a ball circulating assembly. The open nut is slidably fitted over the guider and includes an axial cylinder having an axial opening. An inner spiral channel of the axial cylinder and a spiral channel of the guider form an inner ball race. The open shield is coaxially fitted over the axial cylinder. An inner peripheral wall of the open shield and an outer annular wall of the axial cylinder form an outer ball race. The first circulator and the second circulator are disposed on the axial cylinder. The inner ball race, a first curve of the first circulator, the outer ball race, and a second curve of the second circulator form a ball circulating race, and the ball circulating assembly rolls in the ball circulating race.

A ball screw assembly includes a guider, an open nut, an open shield, a first circulator, a second circulator, and a ball circulating assembly. The open nut is slidably fitted over the guider and includes an axial cylinder having an axial opening. An inner spiral channel of the axial cylinder and a spiral channel of the guider form an inner ball race. The open shield is coaxially fitted over the axial cylinder. An inner peripheral wall of the open shield and an outer annular wall of the axial cylinder form an outer spiral ball race. The first circulator and the second circulator are disposed on the axial cylinder. The inner ball race, a first curve of the first circulator, the outer spiral ball race, and a second curve of the second circulator form a ball circulating race, and the ball circulating assembly rolls in the ball circulating race.

Provided is a power steering apparatus capable of improving accuracy of relative positions of a first circulation member and a second circulation member. A tube 23 includes a first first-tube-side abutment portion 40 and a second second-tube-side abutment portion 51, and a second first-tube-side abutment portion 41 and a first second-tube-side abutment portion 51, which are configured to restrict relative positions of a first tube 31 and a second tube 32 in a circumferential direction relative to a nut 8.

An actuator includes a drive assembly, a ball screw, and a ball nut. The ball nut may include a first nut member, a second nut member; and first arm extending from the first nut member. The first arm may include a first portion and a second portion. The first portion may extend radially outward from the first nut member. The second portion may extend substantially axially from the first portion such that at least some of the second portion is disposed radially outward of the second nut member. A second arm may extend from the second nut member, and the second arm may include a first portion and a second portion. In embodiments, at least part of the second portion of the first arm is disposed radially outward of at least a part of the second portion of the second arm.

Linear actuators driven by everted ball screw assemblies are described herein. In some examples, the everted ball screw assembly includes a hollow screw shaft with internal threads, a ball cylinder concentrically positioned therein and having external threads, and a plurality of balls sized to fit in a substantially contiguous series along a working pathway that is defined by the space between the internal and external threads. One or more limiters prevent the ball cylinder from rotating. A motor rotates the hollow screw shaft, thereby driving the balls along the pathway and imparting linear motion to the ball cylinder, which is coupled to a connecting rod for actuating a load. The ball cylinder in some examples includes an internal return path with scoop elements that are sized and shaped to guide the balls into the internal return path and then back onto the working pathway.

Linear actuators are described herein, In particular embodiments, a linear actuator includes an everted ball screw assembly comprising a hollow screw shaft with internal threads, a ball cylinder concentrically positioned therein and having external threads, and a plurality of bearing balls sized to fit in a substantially contiguous series along a working pathway defined by the space between the internal and external threads. The linear actuator may include a support bearing for rotatably supporting the screw shaft in a housing. The ball cylinder in particular embodiments includes an internal return path along which the balls return to the working pathway. The everted ball screw assembly may include a lash reduction assembly and one or more scoop inserts that are sized and shaped to guide the balls into the internal return path and back onto the working pathway.

The present disclosure provides an actuator assembly having a ball nut comprising a helical track and a ball screw. The ball screw of the actuator assembly includes a first translation bearing track having a first diameter, wherein the helical track and the first translation bearing track form a first translation bearing raceway in which a first translation bearing ball is disposed. The ball screw further includes a second translation bearing track having a second diameter, wherein the helical track and the second translation bearing track form a second translation bearing raceway in which a second translation bearing ball is disposed. The first diameter and the second diameter are not equal.

Provided is an electric actuator, including: a motor part; a motion conversion mechanism part; an operation part; and a terminal part, wherein a hollow rotary shaft configured to support a rotor core of the motor part is supported by a rolling bearing so as to be rotatable, wherein the motion conversion mechanism part is coupled to the hollow rotary shaft, and includes a ball screw, wherein a ball screw nut of the ball screw is arranged inside the hollow rotary shaft, wherein the operation part is coupled to the motion conversion mechanism part, and wherein an inner raceway surface of the rolling bearing is formed on the hollow rotary shaft.

A re-circulating ballscrew assembly comprises a plurality of balls. A ballnut has a ballnut body with a radially inner surface and a helical ballnut groove formed on the radially inner surface. A ballscrew is disposed within the ballnut, the ballscrew comprising a radially outer surface and a ballscrew groove formed on the outer surface, the ballscrew groove cooperating with the ballnut groove to define a helical raceway for the plurality of balls, the helical raceway having a start point and an end point. The ballscrew assembly comprises a return track for the plurality of balls, the return track disposed radially outward of the radially inner surface of the ballnut and connecting the start point and the end point of the helical raceway. The return track extends at least in part through an annular lubricant bath.

A linear electromechanical actuator comprises an electric motor, a ball screw shaft driven by the electric motor and a tubular output shaft receiving the ball screw shaft and rotationally coupled thereto. The ball screw shaft has at least one helical groove formed on a radially outer surface thereof and the output shaft has at least one helical groove formed in a radially inner surface thereof. A plurality of ball elements is received within the grooves for rotationally coupling the ball screw shaft to the output shaft. The ball screw shaft further comprises a ball recirculation element mounted in the radially outer surface of the ball screw shaft. The ball recirculation element interrupts the helical groove in the ball screw shaft and has one or more ball recirculating passages. Each ball recirculating passage comprises an inlet portion a recirculation portion and an outlet portion.