An object of the present invention is to provide a ball screw having a structure in which a screw shaft and a nut satisfy required performance and having improved durability, a method for manufacturing the ball screw, a power steering device, and a method for manufacturing the power steering device.

A ball screw according to the present invention includes: a nut made of a steel substrate having an inner peripheral surface on which a female screw is formed; a screw shaft that is combined with the nut and is made of a steel substrate having an outer peripheral surface on which a male screw facing the female screw is formed; and a plurality of balls arranged between the female screw and the male screw. A surface of the nut in contact with the ball and a surface of the screw shaft in contact with the ball each have carburized layers. A carbon concentration in the carburized layer of the nut is higher than a carbon concentration in the carburized layer of the screw shaft.

A modular electric power steering system is disclosed. The system includes a tubular neck which guides a universal joint. The tubular neck has a certain bend angle. The system further includes a drive assembly that has an electric motor which is controlled by a control unit. The system additionally includes a gearbox assembly having a torque sensor and a gearbox. The system also includes a steering rod that has a shortenable tube. Further, the system includes a gearbox housing that houses the gearbox assembly. In addition, the system includes two tubular toothed rack housing halves that are shortenable. The gearbox housing is disposed between the two toothed rack housing halves. The system also includes two feet which are disposed at the respective outer end of the two toothed rack housing halves. The feet serve to fasten the power steering system to the vehicle. And the feet include a bushing for guiding the toothed rack.

A steering system includes a steering rod mounted for longitudinal axial sliding in a housing and a steering motor acting on the steering rod via a ball screw drive, for which the steering rod forms a ball recirculation screw thread, which interacts with a transmission nut that can be driven by the steering motor. A transmission wheel of a flexible transmission, by means of which driving power of the steering motor is transmitted to the transmission nut, is untiltably connected to an inner ring of a rotary bearing. The transmission nut is pivotably mounted on the transmission wheel about an arbitrary pivot axis, which is oriented perpendicularly to the longitudinal axis of the steering rod. The transmission nut, which is pivoted as a result of a flexural load on the steering rod, can be decoupled from the rotary bearing and from a tensile load on the transmission wheel.

A steering device for detecting an error of a road wheel actuator according to an exemplary embodiment of the present disclosure includes an electronic control unit and a road wheel actuator. The electronic control unit may be electrically connected with a steering wheel of a vehicle, and the road wheel actuator may be electrically connected with the electronic control unit. When the vehicle starts, the electronic control unit may rotate the steering wheel in one direction or an opposite direction to the one direction by driving the road wheel actuator and measure data of the road wheel actuator. A method of determining an error of a road wheel actuator according to another exemplary embodiment of the present disclosure includes a first operation, a second operation, and a third operation.

The present embodiments may provide a steering control method and a steering control device capable of compensating for shimmy even when the torque sensor fails and removing only shimmy components without affecting the steering feel by compensating for shimmy using the road wheel actuator-side rack force signal, rather than the steering feedback actuator-side torque signal.

An electric actuator for a steering system is adapted to control an angle of steered wheels on a vehicle to adjust a direction of travel of the vehicle. The electric actuator includes a housing assembly, an electric motor, and an actuation unit. The housing assembly is arranged around the electric motor and the electric motor is coupled with the actuation unit and configured to cause an actuator rod of the actuation unit to move relative to the housing assembly.

A steering system has a steering rod longitudinally displaceable in a housing and a steering motor acting on the steering rod via a ball screw drive. The steering rod has a recirculating ball thread interacting via spherical transmission elements with a transmission nut driven by the steering motor and that is rotatably mounted by a bearing arrangement with a pivot bearing having an inner ring to which a mechanism wheel is fixedly attached. The transmission nut is pivotably mounted on the mechanism wheel about a pivot axis oriented perpendicularly to the longitudinal axis of the steering rod, and has a curved joint section which interacts with a curved joint section of the mechanism wheel to form a pivoting bearing. In order to realize low-friction movement capability of the pivoting bearing, at least one of the joint sections has a sliding coating, and/or a lubricant is arranged between the joint sections.

A steering system has a steering rod longitudinally displaceable in a housing and a steering motor acting on the steering rod via a ball screw drive. The steering rod has a recirculating ball thread interacting via spherical transmission elements with a transmission nut driven by the steering motor and that is rotatably mounted by a bearing arrangement with a pivot bearing having an inner ring to which a mechanism wheel is fixedly attached. The transmission nut is pivotably mounted on the mechanism wheel about a pivot axis oriented perpendicularly to the longitudinal axis of the steering rod, and has a curved joint section which interacts with a curved joint section of the mechanism wheel to form a pivoting bearing. An elastically deformed spring ring arranged between the joint sections provides freedom from play of the pivoting joint.

An apparatus for use in turning steerable vehicle wheels includes a steering member connected to at least one steerable vehicle wheel. The steering member moves axially to effect turning movement of the at least one steerable vehicle wheel. The steering member has an externally threaded portion. A ball nut assembly is connected with the externally threaded portion of the steering member. The ball nut assembly is rotatable relative to the steering member to axially move the steering member. A first gear member is rotatable in response to rotation of a steering wheel. A second gear member disposed in meshing engagement with the first gear member rotates in response to rotation of the first gear member. The ball nut assembly rotates relative to the steering member in response to rotation of the second gear member.

An actuator (1) for a rear axle steering system of a vehicle includes a thrust rod (2) which is longitudinally displaceable within a housing (3). The thrust rod (2) has a rotation lock (4) having a guide element (5) which is guided in the axial direction in a single-part or multi-part slide rail (6) arranged on the housing (3). An elastomer ring (7) is arranged between the slide rail (6) and the housing (3).