A steering apparatus includes a steering shaft; a steered shaft; a ball screw mechanism; and a motor. A plurality of rolling elements includes large-diameter rolling elements and small-diameter rolling elements. A prescribed diameter difference is set such that when a magnitude of power transmitted between a first screw groove and a second screw groove is a prescribed value or less, only the large-diameter rolling elements transmit the power between the first screw groove and the second screw groove, and when the magnitude of the power transmitted between the first screw groove and the second screw groove exceeds the prescribed value, both the large-diameter rolling elements and the small-diameter rolling elements transmit the power.

A ball screw device includes: a screw shaft the outer peripheral surface of which has a first thread groove; a nut the inner peripheral surface of which is provided with a second thread groove that matches the first thread groove, and the outer peripheral surface of which is provided with a through hole; a plurality of balls that roll between the first thread groove and the second thread groove; a circulation component including a main body part and a pair of leg parts provided on both ends of the main body part, and that is provided on the nut; and a pin component that fixes the circulation component to the nut. Each of the leg parts is inserted into the through hole, the pin component is provided on the leg part in an overlapping manner, and the leg part is retained in the through hole by the pin component.

A ball screw device includes a plurality of ball screw devices. In one ball screw device, a recirculation member is larger than the recirculation member in another ball screw device in terms of one mounting dimension of two mounting dimensions selected from a circumferential length of a part at a side of a pick-up opening portion in each pick-up portion, a circumferential length of a part at a side opposite to the pick-up opening portion in each pick-up portion, a circumferential length of a connection passage portion and an axial length of the connection passage portion, and the recirculation member is smaller than the recirculation member in the other ball screw device in terms of another mounting dimension of the two mounting dimensions, the other ball screw device being different in a diameter of a screw shaft from the one ball screw device.

An attachment for oscillating a bed and a bed oscillating device including a support portion supporting the bed and a driving unit that linearly reciprocates the support portion such that the bed is oscillated. A conversion mechanism of the driving unit is a screw device including a screw shaft, a nut, a plurality of balls, and a circulation member that endlessly circulates the plurality of balls between a first spiral groove of the screw shaft and a second spiral groove of the nut. One of the screw shaft and the nut includes a rotating member configured to rotate in accordance with the rotational motion of the motor, and the other of the screw shaft and the nut includes a reciprocating member configured to be linearly reciprocated via the balls in accordance a rotation of the rotating member.

An electric clutch actuator having an electric motor, a spindle and a gear mechanism which is arranged between the electric motor and the spindle, wherein the gear mechanism is mounted on a base plate which is received in the housing.

An open nut and a ball screw assembly having the open nut are provided. The ball screw assembly includes a guider, an open nut, and a ball circulating assembly. The open nut includes an axial cylinder, an open shield, and two circulators. The two circulators are respectively disposed on a first axial wall and a second axial wall of the axial cylinder with an axial opening. Each of the circulators includes an inner member and an outer member. The inner member and the outer member are assembled to each other and are respectively in communication with an inner ball race between the guider and the open nut and an outer ball race of the open nut. Therefore, the inner ball race, ball races of the two circulators, and the outer ball race form a ball circulating race, and the ball circulating assembly rolls in the ball circulating race.

A ball screw assembly is disclosed herein. The assembly includes a nut having an outer raceway, and at least one notch. A spindle extends inside of the nut, and the spindle defines an inner raceway. A ball-spring assembly includes a plurality of balls supported between the outer raceway and the inner raceway, and at least one reset spring engaged against at least one ball of the plurality of balls At least one end-stop component is engaged against a terminal end of the ball-spring assembly and positioned within the at least one notch. A radially inner side of the at least one end-stop component abuts the spindle. A method of forming the nut for a ball screw assembly is also disclosed herein.

A ballscrew assembly includes a nut having a first helical groove formed on a radially inner surface and defining an axis, a screw disposed along the axis (X) and within the nut and that includes a second helical groove formed on a radially outer surface and opposed to the first helical groove so as to form a helical raceway. The assembly also includes a plurality of balls disposed in the helical raceway and an annular seal disposed radially between the nut and the screw. The seal includes a resilient body and a layer formed of PTFE and disposed radially between the resilient body and the screw and configured to contact the radially outer surface of the screw. An optional annular scraper is disposed axially adjacent to the seal and is configured to receive fluid at one axial end and expel fluid at a second axial end.

In a screw device where a shim is disposed between two nuts, a screw device that can detect preload is provided. The preload detectable screw device includes: two nuts; a shim sandwiched and compressed between the two nuts; a coupling portion configured to couple the two nuts in such a manner as to be incapable of relative rotation to each other; and a force sensor for detecting preload. A contact surface of at least one of the two nuts with the shim is provided with a recess, spaced apart from the coupling portion, in such a manner as to reduce the contact area. The force sensor is attached near the recess on an outer surface of the shim.

An electric actuator for a steering system is adapted to control an angle of steered wheels on a vehicle to adjust a direction of travel of the vehicle. The electric actuator includes a housing assembly, an electric motor, and an actuation unit. The housing assembly is arranged around the electric motor and the electric motor is coupled with the actuation unit and configured to cause an actuator rod of the actuation unit to move relative to the housing assembly.