With respect to a linear motion shaft in which a rack shaft part and a ball screw shaft part are joined to each other by friction welding, coaxiality of a portion having a rack shaft part and a portion having a ball screw shaft part is improved. In a state where a gripped portion 56 formed on the screw shaft part 29 is gripped by a first gripping tool 57 for centering, and a rack shaft part 28 is gripped by a second gripping tool 58 for centering, end portions in the axial direction of the rack shaft part 28 and the screw shaft part 29 are abutted to each other while the screw shaft part 29 and the rack shaft part 28 are relatively rotated by rotating the first gripping tool 57, so that the rack shaft part 28 and the screw shaft part 29 are joined to each other by friction welding.

A method for manufacturing a linear motion shaft includes: manufacturing a first shaft portion, and connecting the first shaft portion and a second shaft portion by friction welding. A first input section is formed in a material for the first shaft portion to obtain the first shaft portion and then a gripped section for centering is formed on the outer peripheral surface of an axially end portion of the first shaft portion on the side connected to the second shaft portion based on the first input section. The friction welding is performed by abutting the axially end portions of the first shaft portion and the second shaft portion in a state where the gripped section is gripped by a first gripping tool for centering, the first shaft portion is rotated with the first gripping tool, and the second shaft portion remains without rotating.

A ball screw device includes: a screw shaft that has a first screw groove on an outer circumferential surface thereof; a cylindrical nut member that has a second screw groove on an inner circumferential surface thereof; plural rolling elements that can roll in a rolling path formed between the first screw groove and the second screw groove; and a lubricant applied to the rolling path, wherein the lubricant has a loss tangent tanδ larger than 0.11, which is measured by dynamic viscoelasticity measurement performed at a temperature of 25° C., an angular frequency of 10 rad/s, and an amount of strain of 0.01%.

An electric power steering apparatus includes: a ball nut, which is coupled to a rack bar therein, slides the rack bar, and has a first coupling portion formed to protrude in radial directions from one side of an external circumferential surface such that a fastening member is coupled to the first coupling portion; a nut pulley having a second coupling portion, which is formed to protrude in radial directions from an internal circumferential surface having a hollow therein and which comes in contact with the first coupling portion and to which the fastening member is coupled, and having an external circumferential surface to which the belt is connected and rotates the ball nut; and a deformation preventing member coupled to an opposite end of a portion of the nut pulley in which the second coupling portion is formed.

An electric powered recirculating ball assembly includes a steering rack. The electric powered recirculating ball assembly also includes a steering gear housing. The electric powered recirculating ball assembly further includes a plurality of rolling elements operatively coupled to the steering rack and in contact with mating geometry of a component operatively coupled to, or integrally formed with, the steering gear housing.

A holding ring for the axial fixing of a rotary bearing of a steering apparatus for motor vehicles on a rotatable component with a cylindrical outer surface onto which an inner bearing shell of the rotary bearing is mounted, wherein the holding ring includes at least one spring tongue which lies in an axial direction resiliently against the inner bearing shell, is improved with regard to a simple design and assembly process in that the holding ring comprises radially inwardly projecting elastic fixing tongues which, in the relaxed state, extend into the radial region of the rotatable component such that, when the holding ring is pushed onto the cylindrical outer surface of the rotatable component, the fixing tongues are deflected elastically in an axial direction opposite to the pushing-on direction and lie with a radial preload force against the outer surface of the rotatable component.

A steering system for steering a wheel of a vehicle includes a track rod for deflecting the wheel, a rack which, by axial movement, leads to control of the track rod, and a housing. The rack is at least partially arranged within the housing. The rack has a convex and/or concave cross-sectional portion. The housing-mounted complementary geometry includes a complementary concave and/or convex shaping, as a result of which a form-fitting connection is produced for realizing the twist prevention.

An electronic power steering apparatus, according to one embodiment of the present invention, comprises: an output shaft rotated by means of a reduction gear connected to a driving motor; a ball screw having an upper end coupled to a lower end of the output shaft, and having outer circumferential screw grooves formed on an outer circumferential surface thereof to rotate in conjunction with the output shaft; a ball nut having gear teeth formed on an outer circumferential surface thereof and inner circumferential screw grooves corresponding to the outer circumferential screw grooves formed on an inner circumferential surface thereof, the ball nut being coupled to the ball screw via a ball and sliding in an axial direction; and a sector shaft, coupled to the gear teeth of the ball nut, for operating a pitman arm while rotating during the axial sliding of the ball nut.

A reaction force generating device for a steering device includes a steering shaft connected to a steering member on which a steering operation is to be performed by a driver, a direct drive motor connected to the steering shaft and configured to generate reaction torque, an electromagnetic brake configured to generate friction torque and including a first friction portion configured to integrally rotate with the steering shaft, a second friction portion provided to face the first friction portion and to be non-rotatable, and an electromagnetic unit configured to press the second friction portion against the first friction portion.

A method for manufacturing a steering shaft of a steering device includes: a reduced-diameter section forming process in which a second-phase member is formed from a first-phase member by forming a reduced-diameter section in the first-phase member; and a ball screw groove forming process in which a third-phase member is formed from the second-phase member by forming a ball screw groove in the second-phase member by rolling.