A bearing screw transfer device which converts a rotational motion of a screw shaft into a linear motion by the medium of a bearing is disclosed. The bearing screw transfer device has a first driving bearing and a second bearing which run along a screw groove of a rotating screw shaft, thereby converting a rotational force of the screw shaft into a translational force of an operating plate disposed on an upper portion of the screw shaft, wherein a two-surface screw groove is formed on the screw shaft, and an outer ring of the first driving bearing runs in contact with one surface of the two-surface screw groove, and an outer ring of the second driving bearing runs in contact with the other surface of the screw groove.

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.

A ball screw assembly includes a guider, an open nut, open shields, a first circulator, a second circulator, and ball circulating assemblies. The open nut is slidably fitted over the guider and includes an axial cylinder having an axial opening. Inner spiral channels of the axial cylinder and spiral channels of the guider form inner ball races. The open shields are coaxially fitted over the axial cylinder. An inner peripheral wall of each of the open shields 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 corresponding to the open shields. The inner ball races, first curves of the first circulator, the outer ball races, and second curves of the second circulator form ball circulating races, and the ball circulating assemblies roll in the ball circulating races.

An electric actuator comprises a housing and an output shaft reciprocatingly received by the housing. There is a screw assembly disposed within the housing and coupled to the output shaft. The screw assembly includes a plurality of annular rollers and a central screw received by the annular rollers. The annular rollers are rotatable about the central screw. There is a motor which includes a stator and a rotor. The rotor has an inner bore which engages the annular rollers. Rotation of the rotor causes the central screw to translate axially relative to the rotor and the output shaft to reciprocate relative to the housing.

A steering device includes a rolling-element bearing that rotationally supports a rotating member in a housing. The rolling-element bearing includes an inner ring, an outer ring, first rolling elements, and second rolling elements. The first rolling elements and second rolling elements are disposed in parallel in the axial direction between the inner ring and the outer ring. The inner ring includes a first split race having a first inner peripheral track surface and a second split race having a second inner peripheral track surface. The steering device further includes a fixing structure configured to fix the rolling-element bearing to the outer periphery of the rotating member in a state where a load is applied to the first split race, the first rolling element, the outer ring, the second rolling element, and the second split race.

An actuation device (1) comprising a threaded shaft (2) connected at one end to driving means adapted to allow the threaded shaft (2) to rotate about its longitudinal axis (a). A movable element (3) is provided with a cylindrical cavity (30) adapted to receive the threaded shaft (2), and configured so that a rotation of the threaded shaft (2) corresponds to a translation the movable element (3) along the longitudinal axis (a). The device (1) has two guiding rods (4,4) coupled to the movable element (3) and adapted to constrain the translation of the latter along a direction parallel to the longitudinal axis (a). Element (3) comprises a first (31) and a second (32) element constrained to each other, wherein the first element (31) is coupled to the threaded shaft (2) and the second element (32) is coupled to the two guiding rods (4,4).

An electric actuator comprises a housing and an output shaft reciprocatingly received by the housing. There is a screw assembly disposed within the housing and coupled to the output shaft. The screw assembly includes a plurality of annular rollers and a central screw received by the annular rollers. The annular rollers are rotatable about the central screw. There is a motor which includes a stator and a rotor. The rotor has an inner bore which engages the annular rollers. Rotation of the rotor causes the central screw to translate axially relative to the rotor and the output shaft to reciprocate relative to the housing.

A bearing screw transfer device which converts a rotational motion of a screw shaft into a linear motion by the medium of a bearing is disclosed. The bearing screw transfer device has a first driving bearing and a second bearing which run along a screw groove of a rotating screw shaft, thereby converting a rotational force of the screw shaft into a translational force of an operating plate disposed on an upper portion of the screw shaft, wherein a two-surface screw groove is formed on the screw shaft, and an outer ring of the first driving bearing runs in contact with one surface of the two-surface screw groove, and an outer ring of the second driving bearing runs in contact with the other surface of the screw groove.

An electric actuator comprises a housing and an output shaft reciprocatingly received by the housing. There is a screw assembly disposed within the housing and coupled to the output shaft. The screw assembly includes a plurality of annular rollers and a central screw received by the annular rollers. The annular rollers are rotatable about the central screw. There is a motor which includes a stator and a rotor. The rotor has an inner bore which engages the annular rollers. Rotation of the rotor causes the central screw to translate axially relative to the rotor and the output shaft to reciprocate relative to the housing.