The alignment of a nut and a nut-side pulley is performed by: a nut insertion step of inserting the nut into the nut-side pulley; a temporary tightening step of, after the nut insertion step, inserting a shaft portion of a fastening bolt in a fastening bolt insertion hole of the nut-side pulley, with the shaft portion being inserted through a spring washer, and then, tightening the shaft portion into an internal thread of the nut until a dimension of the spring washer becomes shorter than a free length and longer than a fully compressed length; an axis deviation adjusting step of adjusting a position of the nut-side pulley relative to the nut to decrease a deviation of the nut-side pulley relative to a rotation axis of the nut after the temporary tightening step; and a final tightening step of further tightening the fastening bolt after the axis deviation adjusting step.

The present invention provides a rack assist type electric power steering apparatus. The power steering apparatus includes: a ball nut coupled to a rack bar via balls to be rotated, and configured to cause the rack bar to slide; a bearing mounted on an outer peripheral surface of the ball nut so as to support rotation of the ball nut; and a support member coupled to at least one of a space between one side of an outer race of the bearing and a housing and a space between the other side of the outer race of the bearing and the housing so as to support the bearing.

A machine tool (10) for machining workpieces (18) has a main spindle (12) which carries a tool holder (14) at its end and is mounted in such a way that it can rotate about an axis of rotation (22) and can move along the axis of rotation (22). A preferably electromagnetic feed device (32) is also provided, which exerts a force (FZ) acting along the axis of rotation s on the main spindle (12). A screw gear (52), which connects a drive (20) for driving the main spindle to the main spindle (12), drives the main spindle (12) in rotation and simultaneously moves it along the axis of rotation (22). The screw-and-nut gearing (52) has a thread (64, 66a, 66b) formed on a first component (54) and a cam (70a, 70b) formed on a second component (12) that cooperates with the thread (64, 66a, 66b). One of the two components (54) is rotated by the drive (20) via a drive gear (57) and is immovably mounted along the axis of rotation (22). The other of the two components is the main spindle (12).

A ball screw nut includes a nut part and a pulley part integrally molded with the nut part on the outer peripheral side of the nut part and having external teeth. The pulley part has a cylindrical portion extending in an axial direction and facing the nut part in a radial direction, and an extended portion extending radially inward from the cylindrical portion and facing the nut part in the axial direction. A restriction part for restricting relative rotation of the nut part and the pulley part is provided between a facing surface of the extended portion facing the nut part and a facing surface of the nut part facing the extended portion.

The disclosure relates to a planetary roller screw drive comprising a threaded spindle nut, a horizontal threaded spindled, a plurality of planetary rolling elements having a planetary rolling element profile, and at least two planetary guide rings. The threaded spindle is arranged concentrically in the planetary guide rings and the spindle nut. The planetary guide rings can be rotated relative to the threaded spindle and the planetary rolling elements are mounted so as to be rotatable about their associated planetary rolling element axis in the planetary guide rings and inside the spindle nut. The planetary rolling element profile of the planetary rolling elements meshes with the threaded spindle. The planetary guide rings are connected to a housing case for conjoint rotation, and the housing case has a housing case lateral surface on which a toothing is formed for coupling in a geared manner to with a continuous traction mechanism.

A power transmission device including a housing and a ball screw device including a nut, a screw shaft, and a plurality of balls. The device includes a pulley device including a driving pulley configured to be driven by receiving power transmitted from a power source, a driven pulley fixed to the nut, and a belt wound around outer peripheral surfaces of the driving pulley and the driven pulley. The device also includes a first bearing and a second bearing disposed between the housing and the nut in a center axis direction parallel with a center axis of the nut; and a preload applying member configured to apply preloads to the first bearing and the second bearing. The first bearing and the second bearing are respectively disposed on both sides of the driven pulley to be a face-to-face combination, and each of the first bearing and the second bearing includes an outer ring engaged with the housing.

A planetary roller screw drive for an actuator of a rear-axle steering system of a motor vehicle, including a planetary roller support which accommodates the planetary rollers and is connected to a drive sleeve for rotation therewith, which drive sleeve is driven rotatably about the screw spindle and is mounted rotatably on a machine part by an axial angular contact roller bearing which is arranged coaxially with respect to the drive sleeve and of which the rollers are in rolling contact with angled-bearing raceways which are inclined with respect to a plane arranged transversely with respect to the axis of rotation of the drive sleeve.

This extendable device includes: a base member; a first ball screw that is provided to the base member and that rotates according to a driving force supplied from a drive source; a first movable member that is coupled to the base member via the first ball screw and that moves relative to the base member as the first ball screw rotates; a second ball screw that is provided to the first movable member and that rotates as the first movable member moves; a third ball screw that is provided to the first movable member; a transmission mechanism that transmits the rotation of the second ball screw to the third ball screw; and a second movable member that is coupled to the first movable member via the third ball screw and that moves relative to the first movable member as the third ball screw rotates.

A ball screw device includes a screw shaft having a first screw groove formed on an outer circumference thereof, a ball screw nut having a second screw groove formed on an inner circumference thereof, and a plurality of balls disposed in a spiral ball raceway wherein the first screw groove and the second screw groove face each other. A circulation member is attached to an attachment hole radially penetrating the ball screw nut and a circulation path is formed, the circulation path allowing endless circulation of each of the balls rolling in the ball raceway by short-circuiting between two points of the ball raceway.

A linear drive system has an actuator (10), which can be moved in a translatory manner by an electric drive (12) and which is coupled to a mechanical energy storage (16) in the form of a spring (32). In the event of a loss of energy at the electric drive (12) or in an emergency operation, the actuator (10) travels to a predeterminable position and in so doing exerts an actuating force. One free end of the spring (32) is supported at the free end of the spindle housing (20), and the other free end of the spring (32) is supported at a closing part (36) of the actuator (10) or at the actuator (10) itself and is tensioned in every travel position of the actuator (10).