A ball screw in a steering system has a groove between the inner peripheral surface of a cylindrical ball nut through which a steered shaft extends and the outer peripheral surface of the steered shaft, and balls are accommodated in the groove. The balls rolling and flowing in the groove are returned from downstream to upstream via deflectors and a return passage member disposed in the ball nut. The return passage member has a first connection portion curved to connect one end of a linear portion of the return passage member to the first deflector, and a second connection portion curved to connect the other end of the linear portion to the second deflector. Each connection portion has an opening that opens in the return passage member longitudinal end face and an opening that opens in the return passage member outer periphery of toward the centerline of the ball nut.

A steering system includes a motor, a rack shaft, and a nut that is screw-thread on the rack shaft via a plurality of balls. The steering system further includes a reduction mechanism having a driving pulley, a driven pulley, a belt, and an idler pulley that applies tension to the belt. The steering system further includes a housing that houses the motor, the rack shaft, the nut, and the reduction mechanism. Compressive rigidity in an axial direction is set to vary between a near-end area and a far-end area of the housing. The idler pulley is provided so as to contact a portion of the belt which is loosened when end contact occurs at an axial end of the housing where the compressive rigidity is set to a larger value.

A sensor device for a steering actuator, the sensor device may include: a pinion shaft mounted on a housing part; a first pinion gear integrated with the pinion shaft by injection molding; and a sensor unit coupled to the first pinion gear.

A steering system includes a rack housing in which a rack shaft is housed, rack ends fitted to respective end portions of the rack shaft and coupled to respective steered wheels, and shock-absorbing members provided between the rack housing and the respective rack ends. When the rack shaft moves in a direction in which an end face of the rack end approaches a restricting surface of the rack housing and thus the rack shaft reaches a position after the shock-absorbing member is compressed by a compression amount, a control unit creates a normal input end through electronic stopper control of reducing an assisting force to be generated by a motor. This restricts movement of the rack shaft in a direction in which the end face approaches the restricting surface.

A motor is contained in a motor container space. A controller is contained in a controller container space. The motor container space and the controller container space are arranged in series in a direction of a rotation axis of a motor shaft, while interposing a partition wall therebetween. The motor shaft is inserted in a motor shaft through-hole of the partition wall. A magnet is disposed at an end of the motor shaft, in the controller container space. A rotation sensor is disposed in the controller container space oppositely to the magnet, for monitoring a rotational position of the motor shaft on the basis of variation in magnetic field due to rotation of the magnet. A cover made of nonmagnetic metal is disposed between the magnet and the rotation sensor so as to cover the motor shaft through-hole.

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 steering assembly includes a rack assembly coupled to a road wheel. The rack assembly includes a housing, a ball screw, a bearing, and a retainer. The housing defines an injection port. The ball screw is at least partially received within the housing. The bearing is received within the housing and rotatably supports the ball screw. The retainer is received within the housing and includes a first retainer portion and a second retainer portion. The first retainer portion cooperates with the housing. The second retainer portion extends from the first retainer portion and is spaced apart from the housing. The second retainer portion defines a channel. The channel, the second retainer portion, and a surface of the housing defines an injection pocket.

According to embodiments, there may be provided a rack-driven steering device, comprising a ball nut coupled with a ball screw via balls and rotating to slide the ball screw, a ball nut gear provided on an outer circumferential surface of the ball nut, a motor gear provided on a shaft of a motor providing driving force to the ball nut and disposed in parallel with the ball screw, and a middle gear coupled between the ball nut gear and the motor gear and transferring the driving force from the motor.

A steering system for an autonomous vehicle or a steer-by-wire vehicle is simpler than a rack and pinion mechanism. The pinion is replaced by a roller and the toothed portion of the rack is replaced by a flat section. The bar, which replaces the rack is translated along its axis by an electric actuator such as a ball screw. The roller and a yoke prevent out of axis movement and prevent rotation about the axis.

A ball screw device includes a screw shaft having a first thread groove on an outer peripheral surface and a nut having a second thread groove provided on an inner peripheral surface, a notch provided on an end face, and a return hole provided on a bottom surface of the notch orthogonal to an axial direction of the screw shaft and passing through in the axial direction. An end deflector fits into the notch. The nut includes a curved surface portion at a position of a lateral surface of the notch between the second thread groove and the return hole. In a first section, the curved surface portion includes a portion that draws an arc centered at a point positioned outside the second thread groove in a radial direction around a rotation axis of the nut.