A vehicular steering device includes a turning shaft, a housing storing therein the turning shaft, a stopper provided at a shaft end of the turning shaft, and an annular elastic body. An opening of the housing is formed in a U-shaped cross-sectional shape and in an annular shape opened toward the stopper by an external cylinder portion and an internal cylinder portion. The elastic body includes a first elastic portion and a second elastic portion. The first elastic portion is supported by an inner circumferential surface of the external cylinder portion and the bottom surface, and is provided with a first clearance from an outer circumferential surface of the internal cylinder portion. The second elastic portion extends toward the stopper from the first elastic portion, and is provided with a second clearance larger than the first clearance from the inner circumferential surface of the external cylinder portion.

A ball screw device is provided, including a retainer that can properly retain balls. The difference between a diameter being the pitch circle diameter of the ball screw device and the outside diameter of the rack shaft is set to be equal to or larger than the difference between the bore diameter of a ball screw nut and the diameter. The thickness center diameter of the retainer is set to be smaller than the diameter. Even when the inclination angle is reduced, the clearance between the inclined surfaces of each retainer groove on the radial inside can be easily set to be smaller than the diameter of the balls because the bore diameter of the retainer is set to be smaller. Thus, even when the inclination angle of the inclined surfaces is set to be smaller, the balls can be properly retained.

A ball screw device and a steering system that include a retainer having more uniform stiffness are provided. Between a rack shaft and a ball screw nut, a cylindrical retainer having a plurality of retainer grooves that retain balls in a rollable manner is provided. Each retainer groove has two short inner surfaces that intersect the extending direction of the retainer groove and two long inner surfaces that intersect these short inner surfaces and extend along the extending direction of the retainer groove. In each of interior-angle portions where the short inner surfaces and the long inner surfaces intersect, a corner round surface is formed. The radius of the corner round surface is set to be smaller than one half of the width of the retainer groove.

A ball screw mechanism that allows a reduction in contact and friction between a retainer and a nut is provided. In a ball screw mechanism, a nut is threadedly engaged with a screw groove of a rack shaft through balls retained in a retainer groove of a retainer, and an axial force is applied to the rack shaft in accordance with rotation of the nut. The nut includes a uniform diameter portion having a uniform inside diameter and enlarged diameter portions each having an inside diameter larger than that of the uniform diameter portion. The enlarged diameter portions are provided at opposite axial ends of a region on an inner circumferential surface of the nut. The region faces the retainer groove and retainer ends adjoining to opposite axial ends of the retainer groove.

Disclosed herein is a bearing assembly for a vehicle steering apparatus, which includes a bearing including an inner ring fastened to a rack bar, an outer ring disposed outside the inner ring with a ball interposed therebetween, and a sealing member provided between the inner ring and the outer ring, and an elastic clip including a body pressed against an outer peripheral surface of the outer ring, fastening portions bent toward sides of the outer ring from both ends of the body, and elastic portions extending from respective ends of the fastening portions and protruding laterally of the outer ring to each have a curvature.

A motive power transmission mechanism includes a motor, a drive pulley, a driven pulley, a belt, a housing, and a cap. The motor includes an output shaft and a motor main body. The drive pulley is configured to rotate together with the output shaft. The belt is wound across the drive pulley and the driven pulley to transmit torque from the drive pulley to the driven pulley. The housing accommodates the drive pulley, the belt, and the driven pulley. The housing includes a work window which faces the belt and through which the belt undergoes work from outside of the housing. The cap is configured to close the work window when the work is not performed. The cap includes a porous portion having air-permeability and water-impermeability.

A steering gear for a steer-by-wire steering system of a motor vehicle may include a coupling rod mounted in a steering gear housing. A threaded spindle may be formed on the coupling rod and surrounded by a spindle nut as part of a spiral gear. The coupling rod may be displaceable along a longitudinal axis by way of the spiral gear. The coupling rod can be mounted in the steering gear housing by way of a plain bearing so as to be displaceable along the longitudinal axis. The plain bearing is configured to compensate for thermal expansions between the steering gear housing and the spindle nut.

A power steering apparatus and a control circuit for a power steering apparatus are provided. The power steering apparatus detects an abnormality in the power steering apparatus based on whether there is a periodic change within a predetermined frequency range with respect to the number of rotations of an electric motor, a steering velocity, or a steering torque.

A vehicle steering device includes a turning shaft held in a housing so as to be movable in the axial direction, a ball screw transmitting drive force produced by an electric motor to the turning shaft, a bearing supporting a nut, which is a component of the ball screw, so as to be rotatable relative to the housing, and annular elastic members that support side faces of the bearing in the axial direction of the turning shaft across the entire circumference, and are formed of an elastic material. The elastic members include respective first elastic portions having a first load characteristic that gently increases the ratio of compression load per a unit compression amount deforming in the axial direction of the turning shaft, and respective second elastic portions having a second load characteristic that keenly increases the ratio in comparison with the first load characteristic.

An electric power steering apparatus is configured to provide steering assistance as rotary torque of a driving toothed-pulley fixedly fitted to a rotary shaft of an electric motor is transmitted through a toothed belt to a driven toothed-pulley that rotates together with a ball screw nut in an integrated manner. The electric power steering apparatus is configured such that the amount of axial travel of a rack shaft is limited when a rack end and a housing come into contact with each other in the axial direction. The electric power steering apparatus includes a tilt allowing portion configured to cause the ball screw nut to tilt relative to a ball screw shaft such that the distance between the center of rotation of the driven toothed-pulley and that of the driving toothed-pulley increases when the rack end and the housing come into contact with each other in the axial direction.