Provided is a power steering device capable of causing control that uses a pump device and control that uses an electric motor on an input shaft to cooperate with each other. The power steering device includes a power cylinder including a pair of hydraulic chambers partitioned by a piston and configured to generate a steering assist force for a steered wheel, a pump device configured to be driven through control by a first electric motor and configured to discharge working fluid, a rotary valve configured to selectively supply the working fluid supplied from the pump device to the pair of hydraulic chambers in accordance with relative rotation between the input shaft and the output shaft, a second electric motor provided so as to surround at least a part in an axial direction of the input shaft and configured to control the rotation of the input shaft, and a second electric motor control part installed in a control device and configured to output a control signal for controlling driving of the second electric motor based on a revolution number signal of the first electric motor.

Provided is a power steering device capable of causing control that uses a pump device and control that uses an electric motor on an input shaft to cooperate with each other. The power steering device includes a power cylinder including a pair of hydraulic chambers partitioned by a piston and configured to generate a steering assist force for a steered wheel, a pump device configured to be driven through control by a first electric motor and configured to discharge working fluid, a rotary valve configured to selectively supply the working fluid supplied from the pump device to the pair of hydraulic chambers in accordance with relative rotation between the input shaft and the output shaft, a second electric motor provided so as to surround at least a part in an axial direction of the input shaft and configured to control the rotation of the input shaft, and a second electric motor control part installed in a control device and configured to output a control signal for controlling driving of the second electric motor based on a revolution number signal of the first electric motor.

A control system and method for a hydraulic-power steering system of a vehicle including magnetic torque overlay (MTO) is provided. The control system and method minimize undesirable vibration in a handwheel of the vehicle as a result of disturbance in its front road wheels (e.g., road-wheel imbalance). In the control system and method, a base torque command is determined or generated. At least the base torque command is passed to a disturbance-rejection module. The disturbance-rejection module modifies the base torque command to minimize the vibration.

Technical solutions for compensating for lash in a steering system are described. An example method includes determining a rack pressure value based on a driver torque value and a differential pressure across a rack of the steering system. The method also includes determining a compensation friction value based on a position of a handwheel of the steering system and a speed of a vehicle equipped with the steering system. The method also includes computing a pressure value based on the rack pressure value and the compensation friction value. The method also includes generating a torque command using the pressure value, the torque command being added to the driver assist torque for the steering system.

In one aspect of the invention, a torsion bar assembly is provided. The assembly includes a first shaft having a first bore, a second shaft having a second bore, the second shaft operatively coupled to the first shaft, and a torsion bar positioned within the first and second bores. The torsion bar includes a splined first end having a first diameter extending to a first end face having a diameter generally the same as the first diameter, a splined second end having a second diameter extending to a second end face having a diameter generally the same as the second diameter, and an active diameter extending between the splined first end and the splined second end. The torsion bar is fabricated from a material having a hardness greater than 45 Rockwell C-Scale.

A steering shaft component (10) comprises a first and a second steering shaft section (12, 14) and at least a first bending section (28x) extending between the first and the second steering shaft sections (12, 14). The first bending section (28x) is formed integrally with at least one of the steering shaft sections (12, 14), but has a different cross section from this steering shaft section (12, 14). Furthermore, a mechanical stop for limiting the maximum angle of rotation of the two steering shaft sections relative to each other is provided.

A steering shaft for a motor vehicle steering system may be used in connection with a variety of power assistance mechanisms. The steering shaft may comprise a first shaft part and a second shaft part that are rotationally-elastically coupled by way of a torsion bar. In order to transmit torque, the torsion bar may be received in a bore of the first shaft part and coupled to both the first and second shaft parts. In many cases, a first end of the torsion bar is coupled to the first shaft part, and a second end of the torsion bar is coupled to the second shaft part. The torsion bar may be mounted in the bore such that it can be rotated with respect to the first shaft part via a bearing element. In some examples, the bearing element comprises a prestressing element.

A power steering assist system includes a hydraulic assist power steering assembly configured to couple to a vehicle steering gear, and a hydraulic pump having an electric motor, the hydraulic pump configured to supply pressurized hydraulic fluid to the hydraulic assist power steering assembly.

A power steering assist system includes a hydraulic assist power steering assembly configured to couple to a vehicle steering gear, and a hydraulic pump having an electric motor, the hydraulic pump configured to supply pressurized hydraulic fluid to the hydraulic assist power steering assembly.

A steering device includes a control unit that includes a hydraulic abnormality determiner. The hydraulic abnormality determiner is configured to determine a hydraulic abnormality to be present in a pair of liquid chambers of a power cylinder of the steering device, in response to satisfaction of a condition that a total torque of a steering torque measured by a torque sensor and a motor assist torque provided by an electric motor is greater than a predetermined threshold torque. The control unit is configured to increase the motor assist torque in response to satisfaction of a condition that the hydraulic abnormality determiner determines the hydraulic abnormality to be present.