In a steering device of the present invention, an electric motor rotates a steering shaft through a reduction mechanism, and the reduction mechanism and a torque sensor are accommodated in an integrally-structured housing. With this, the present invention can provide a steering device that is capable of suppressing increase in size of the electric motor.

A power steering system includes a steering shaft, a linkage assembly, a first power assist assembly, and a second power assist assembly. The linkage assembly includes an input member drivingly connected to the steering shaft and an output member adapted to be drivingly connected to steerable wheels. The first power assist assembly is drivingly connected to the steering shaft and is arranged to apply a torque to the steering shaft to supplement a driver input force and change the direction of the steerable wheels. The second power assist assembly includes an electric motor drivingly connected to one of the steering shaft and the linkage assembly. The electric motor is arranged to apply torque to the steering shaft or the linkage assembly to change the direction of the steerable wheels with or without a presence of the driver input force to the steering shaft.

A power steering system includes a steering shaft, a linkage assembly, a first power assist assembly, and a second power assist assembly. The linkage assembly includes an input member drivingly connected to the steering shaft and an output member adapted to be drivingly connected to steerable wheels. The first power assist assembly is drivingly connected to the steering shaft and is arranged to apply a torque to the steering shaft to supplement a driver input force and change the direction of the steerable wheels. The second power assist assembly includes an electric motor drivingly connected to one of the steering shaft and the linkage assembly. The electric motor is arranged to apply torque to the steering shaft or the linkage assembly to change the direction of the steerable wheels with or without a presence of the driver input force to the steering shaft.

An improved steering shaft assembly is provided. The steering shaft assembly further includes an output shaft that is rotatable with respect to the input shaft. The output shaft includes a rotary valve portion and a longitudinal portion. The steering shaft assembly further includes a torsion bar coupled to the input shaft and coupled to the output shaft distal from the input shaft. The steering shaft assembly further includes a mid-coupler extending around about the longitudinal portion of the output shaft and adapted to cooperate with the rotary valve portion of the output shaft. The steering shaft assembly further includes a screw mechanism extending about the longitudinal portion of the output shaft and adapted to cooperate with the mid-coupler. The screw mechanism is adapted to move laterally relative to the output shaft to maintain transfer of power from between output shaft and the screw mechanism despite misalignments therebetween.

A work vehicle includes a hydraulic actuator, a control valve, a pressure sensing unit, a force imparting component, and a controller. The hydraulic actuator varies a steering angle. The control valve controls flow of fluid supplied to the hydraulic actuator. The operation member is configured to be operated by an operator and to control the control valve when varying the steering angle. The pressure sensing unit senses a pressure produced by the hydraulic actuator. The force imparting component imparts an assisting force or a counterforce to operation of the operation member. The controller controls the force imparting component so as to generate resistance to operation of the operation member based on a pressure value sensed by the pressure sensing unit.

A work vehicle includes a hydraulic actuator, a control valve, a pressure sensing unit, a force imparting component, and a controller. The hydraulic actuator varies a steering angle. The control valve controls flow of fluid supplied to the hydraulic actuator. The operation member is configured to be operated by an operator and to control the control valve when varying the steering angle. The pressure sensing unit senses a pressure produced by the hydraulic actuator. The force imparting component imparts an assisting force or a counterforce to operation of the operation member. The controller controls the force imparting component so as to generate resistance to operation of the operation member based on a pressure value sensed by the pressure sensing unit.

The present embodiments relates to a reducer of an electric power steering device. An embodiment of the present embodiments provides a reducer of an electric power steering device, including: a worm shaft having a first worm shaft bearing and a second worm shaft bearing coupled to one end portion, which is connected to a motor shaft, and to the other end portion, which is opposite thereto, respectively; a gear housing that contains the first worm shaft bearing, the second worm shaft bearing, and the worm shaft; and a support member coupled to the inner peripheral surface of the hear housing so as to support the outer race of the second worm shaft toward the worm wheel and filled with a viscoelastic fluid.

A work vehicle is articulated with a front frame and a rear frame linked to the front frame. The work vehicle includes a hydraulic actuator, a control valve, an operation member and a force imparting component. The hydraulic actuator is configured to be hydraulically driven to change a steering angle of the front frame with respect to the rear frame. The control valve is configured to control flow of fluid supplied to the hydraulic actuator. The operation member is linked to the control valve and configured to be operated by an operator. The force imparting component is configured to impart an assist force or a counterforce to an operation of the operation member.

A ball-nut steering system of a conventional vehicle includes a first and a second cylinder chamber for receiving a fluid, a first feed line for conducting fluid from a pump to the first cylinder chamber, and a device for damping and/or easing pulsations of the fluid. The device is arranged inside the first cylinder chamber and/or inside the first feed line. The first cylinder chamber has a smaller volume for receiving the fluid than the second cylinder chamber.

A ball-nut steering system of a conventional vehicle includes a first and a second cylinder chamber for receiving a fluid, a first feed line for conducting fluid from a pump to the first cylinder chamber, and a device for damping and/or easing pulsations of the fluid. The device is arranged inside the first cylinder chamber and/or inside the first feed line. The first cylinder chamber has a smaller volume for receiving the fluid than the second cylinder chamber.