According to the embodiments, it is possible to mitigate noise by compensating for the clearance inside the bearing supporting the rotation of the ball nut and the clearance between the ball nut and the ball screw and prevent excessive friction between the ball nut and the ball screw and inside the bearing to thereby allow the driver a better steering feel.

According to embodiments of the present disclosure, it is possible to easily adjust the tension of the belt, and simplify the motor installation structure in the steering system, and share a motor between vehicle types.

A steering gear for a steer-by-wire steering system of a motor vehicle may include a coupling rod which is supported in a steering gear housing and on which a threaded spindle is formed, with the threaded spindle being surrounded by a spindle nut. The threaded spindle and the spindle nut may be part of a helical gearing, and the coupling rod is movable along a longitudinal axis by way of the helical gearing. The coupling rod is movably mounted in the steering gear housing along the longitudinal axis by way of a pressure piece having two bearing elements arranged on opposite sides of the coupling rod in a circumferential direction of the longitudinal axis.

A ball screw device includes a screw shaft, a plurality of balls, a nut, a pair of guide members, and a transmission member. The nut has a pair of large-diameter portions and a small-diameter part between the two large-diameter portions. The two guide members are attachable to and detachable from an outer circumferential surface of the small-diameter portion in a radial direction and are located with a certain gap in the outer circumferential direction of the small-diameter portion. A fitting portion of the transmission member fits over the two large-diameter portions such that the fitting portion covers the two guide members while restricting radially outward displacements thereof. The fitting portion works with the small-diameter portion and the two guide members to define a circulation passage through which the balls are circulated. The transmission member is coupled to the nut.

A steering device includes: a first steering mechanism including a first ball nut steering, and a first motor actuator, the first ball nut steering including a first output shaft, a first ball screw, and a first transmitting mechanism, the first motor actuator arranged to provide a rotation force to the first output shaft, a second steering mechanism including a second ball nut steering, and a second motor actuator, the second ball nut steering including a second output shaft, a second ball screw, and a second transmitting mechanism, the second motor actuator arranged to provide a rotation force to the second output shaft, a connection member arranged to connect the first transmitting mechanism and the second transmitting mechanism so as to interlock a movement of the first transmitting mechanism and a movement of the second transmitting mechanism.

A vehicle steering system, including: a steering actuator including an electric motor, a steering rod configured to steer a wheel by a steering amount, and a motion converting mechanism configured to convert a rotating motion of a motor rotation shaft into a motion of the steering rod; first and second motor rotation angle sensors configured to detect a motor rotation angle; a steering amount sensor configured to detect a motion amount of the steering rod as the steering amount; and a controller configured to execute a steering amount control and to perform detection-value inappropriateness determination in which it is determined that any one or two of a detection value of the first motor rotation angle sensor, a detection value of the second motor rotation angle sensor, and a detection value of the steering amount sensor are inappropriate based on comparison among the detection values.

An electric power steering apparatus includes left and right swing arm members, right and left tie rods pivotally connected at inner ends to arm portions of the swing arm members via a relay rod pivotally connected to the arm portions at both ends, a rack-and-pinion device in which one end of a rack bar is connected to the arm portion of one of the swing arm members, and a steering input transmission system that transmits a steering input to the rack-and-pinion device. An electric steering assist force applying device is connected to the arm portion of the other swing arm member, and applies a force to assist the other swing arm member to swing.

To provide a steering device capable of highly precisely controlling turning angles of steered wheels without changing a layout of members. Provided is a steering device (10A) including: a center arm (26) having one end portion configured to swing in a right-and-left direction with respect to a vehicle body (BD) in synchronism with rotation of a steering shaft (22); a rod member (40A), which is coupled to the one end of the center arm (26), and is configured to move in the right-and-left direction, to thereby change turning angles of steered wheels (WR and WL); and a rod-member drive device (50) configured to linearly move the rod member (40A) in the right-and-left direction through use of a driving force source. The rod member (40A) is supported such that movement of the rod member (40A) in the right-and-left direction of the vehicle body (BD) is allowed, but movement of the rod member (40A) in a front-and-rear direction and an up-and-down direction of the vehicle body (BD) is restricted. The one end portion the center arm (26) and the rod member (40A) are coupled so as to be relatively movable in the front-and-rear direction of the vehicle body (BD).

According to the present embodiments, it is possible to reduce components, e.g., pinion and support yoke, save costs by simplifying the shape and assembly process, reduce operation and reverse steering noise due to inter-gear friction, and driving friction, and enhance durability.

A steering system to steer wheels by a movement of a steering shaft, including: the steering shaft; an electric motor; a converter configured to convert a rotational motion of the motor into the movement of the steering shaft; a motor rotation angle obtainer configured to obtain a motor rotation angle from a zero point position; a movement-amount-related-amount obtainer configured to obtain a movement-amount-related amount that is a movement amount of the steering shaft from a neutral position or a physical amount in a one-to-one correspondence with the movement amount; and a controller including a malfunction detector configured to detect a presence or absence of a malfunction of the converter in a mode that differs depending on a temperature state of the steering system, based on the motor rotation angle from the zero point position obtained by the motor rotation angle obtainer and the movement-amount-related amount obtained by the movement-amount-related-amount obtainer.