A ball return tube for connecting openings of a ball nut to circulate balls comprises tube end portions for being coupled to the openings of the ball nut, and a tube body connecting the tube end portions so that the balls can pass through the tube body. The ball return tube is constructed in first and second tube portions fixedly joined together by structures included in a first projection protruding from a first surface of the tube body. The ball return tube further comprises one or more of a second projection protruding from a second surface of the tube body in a direction toward the ball nut, a third projection protruding from a lateral side surface of the tube body, and a fourth projection protruding from the tube open end portions so that the projections can be coupled to corresponding recesses of the ball nut.

The present invention provides a power steering apparatus capable of improving a noise/vibration characteristic derived from a pitch difference. Assuming that a belt pitch refers to a pitch between a plurality of belt tooth portions, the belt pitch in a first state refers to the belt pitch when the power steering apparatus is in an unloaded state that no electric power is supplied to an electric motor, the belt pitch in a second state refers to the belt pitch on one side pulled by a motor pulley when electric power is supplied to the electric motor, and a first pulley pitch refers to a pitch between a plurality of tooth portions of a first pulley, which is one of the motor pulley and a nut pulley that is a pulley on a smaller diameter side, a power steering apparatus satisfies

the belt pitch in the first state<the first pulley pitch, (1)

and

an absolute value of (the first pulley pitchthe belt pitch in the second state)<the first pulley pitchthe belt pitch in the first state. (2)

A turning device includes a turning shaft having a first ball screw groove as one of a left screw and a right screw and a second ball screw groove as the other of the left screw and the right screw and turning wheels to be turned by moving in an axial direction, a first electric motor generating a first driving force, a second electric motor operating independently of the first electric motor and generating a second driving force, a first ball screw nut transmitting the first driving force generated by the first electric motor to the first ball screw groove, a second ball screw nut transmitting the second driving force generated by the second electric motor to the second ball screw groove, and a rotation regulating part regulating relative rotation of the turning shaft around an axis with respect to a housing.

A rack housing and a reduction drive housing accommodate a ball screw mechanism and a reduction drive. Within the rack housing and the reduction drive housing, a gap is provided between the left end of a nut and the rack housing, and a gap is provided between the right end of the nut and the rack housing. A groove serving as a communication path in communication with the gaps on both axial sides of the nut is provided in the outer circumferential surface of the nut. The groove is provided so as to avoid a recirculation path provided in the nut. The groove is provided axially and rectilinearly from the end of the nut that is located on the side opposite to a flange, to the flange and is provided along the flange.

A steering system equipped with a linear electric actuator includes: a casing, a shaft slidably coupled to the casing with respect to a sliding axis and provided with an end that protrudes externally from said casing, an electric motor, which is housed in the casing and provided with a stator and a rotor that is axially hollow and coaxial with the shaft, in which the rotor is operable in rotation with respect to an axis of rotation parallel to the sliding axis, a nut screw integrated in rotation with the rotor of the motor and provided with an internal thread, the nut screw includes a first cylindrical portion and a second cylindrical portion, axially arranged side by side, a joint adapted to make the first cylindrical portion and the second cylindrical portion integrated in rotation, and a helical groove surface integrated with the shaft and coupled to the internal thread.

A steering apparatus includes a steered shaft; a rack housing; a ball screw nut; a bearing disposed between an inner peripheral surface of the rack housing and an outer peripheral surface of the ball screw nut, the bearing supporting the ball screw nut such that the ball screw nut is rotatable with respect to the rack housing; and a tubular rack boot covering an axial end portion of the rack housing. The rack housing includes a partition wall protruding radially inward from a cylindrical inner peripheral surface of the rack housing and separating a ball screw chamber housing the ball screw nut and an inner chamber of the rack boot. The partition wall has a through-hole through which the steered shaft extends, and a drain passage provided vertically below the through-hole and providing communication between the ball screw chamber and the inner chamber of the rack boot.

Provided is a ball screw device in which a deflector can securely be prevented from falling into a nut when the deflector is attached. A ball screw device includes a ball screw shaft, a nut, rolling elements, a ball recirculation path, and a deflector. An attachment hole has a pair of first faces. The deflector has a pair of second faces that respectively face the pair of first faces in a state in which the deflector is housed in the attachment hole. The first faces of the attachment hole and the second faces of the deflector have a locking structure in which the first faces and the second faces respectively lock each other in an improper state in which a part of the deflector is inserted into the attachment hole in a posture different from a posture of the deflector housed in the attachment hole.

A rack-parallel steering system that prevents entry of abrasion powder into a rolling bearing is provided. A steering system includes a steered shaft, a rolling element screw portion, a rolling element nut, and a ball screw device. The steering system includes: a motor including an output shaft offset from the steered shaft; a drive force transfer mechanism including a toothed drive pulley, a toothed driven pulley, and a toothed belt; and a rolling bearing supporting a ball screw nut to be rotatable relative to a housing. A first seal member that contacts an outer ring and an inner ring is provided on a side surface of the rolling bearing on the driven pulley side. A second seal member that does not contact the inner ring is provided on a side surface of the ball bearing on the side opposite to the side surface on the driven pulley side.

A steering assembly includes a steering member and an adjustment assembly. The steering member has a first side, a second side adjacent the first side, a third side adjacent the second side and disposed opposite the first side, and a fourth side adjacent the third side and disposed opposite the second side. The adjustment assembly includes a first adjustment member and a second adjustment member. The first adjustment member is arranged to apply a first biasing force to the first side and a second biasing force to the second side. The second adjustment member is arranged to engage the third side and the fourth side.

A rack bar blank for a steering system is provided. The rack bar blank includes a first region having a circular cross-section. The rack bar blank also includes a second region having a flattened surface along a length thereof, the flattened surface present prior to formation of teeth.