In a steering device (PS1) according to the present embodiment, a preload applying mechanism (6) provides a rotation torque to one side in a rotation direction of a ball nut (4) by a reaction force generated by elastic abutment of a plunger (61) on a tooth tip of a first sector tooth (321) of a sector gear (32). Therefore, in the steering device (PS1), unlike conventional steering device, there is no need to provide a pressed portion to be pressed by the plunger (61) separately from the sector gear (32). Increase in size of a sector shaft (3) due to formation of the pressed portion can therefore be suppressed.

A control unit is provided for a vehicle with a steering device having a pump device, which has a pump and an electric motor, a transmission, and a valve. The control unit is designed to provide, in a preheating phase for heating the working medium, a motor signal to the electric motor for operating the electric motor of the steering device, and to provide a valve opening signal to the valve for opening the valve of the steering device.

A steering device includes: a steering shaft; a transmitting mechanism configured to transmit the rotation of the steering shaft to a steered wheel; a power cylinder; a rotary valve configured to selectively supply a hydraulic fluid to the pair of the fluid chambers in accordance with the rotation of the steering shaft; and an electric motor configured to provide a rotation force through a speed reduction device to the steering shaft, the steering shaft including a first shaft connected to the steering wheel, and a second shaft connected to the first shaft, and configured to output the rotation force inputted from the first shaft, to the transmitting mechanism side, and the electric motor being connected through the speed reduction device to the second shaft.

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.

A steering shaft 10 is constructed by an input shaft 11, an intermediate shaft 13 connected to the input shaft 11 through a first torsion bar 12 and an output shaft 15 connected to the intermediate shaft 13 through a second torsion bar 14, and around the input shaft 11, there is provided a first resolver 51 for detecting a rotation angle of the input shaft 11 and around the intermediate shaft 13, there is provided a second resolver 52 for detecting a rotation angle of the intermediate shaft 13, and the first and second resolvers 51 and 52 are arranged to constitute a torque sensor TS that detects a steering torque.

A steering system includes: a steering shaft to which a steering member is coupled; a worm wheel attached to the steering shaft so as to be rotatable integrally with the steering shaft; a housing that houses the worm wheel; an output shaft that is coaxial with the steering shaft and rotatable relative to the steering shaft and coupled to a steering operation mechanism; and a clutch mechanism that enables and disables transmission of power between the steering shaft and the output shaft. The clutch mechanism is housed and disposed in an internal space in the housing.

A steering system includes: a steering shaft to which a steering member is coupled; a worm wheel attached to the steering shaft so as to be rotatable integrally with the steering shaft; a housing that houses the worm wheel; an output shaft that is coaxial with the steering shaft and rotatable relative to the steering shaft and coupled to a steering operation mechanism; and a clutch mechanism that enables and disables transmission of power between the steering shaft and the output shaft. The clutch mechanism is housed and disposed in an internal space in the housing.

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 self-setting valve assembly includes a plug, a first plunger assembly, a second plunger assembly, and a biasing member. The plug has a first portion and a second portion. The first plunger assembly is movably disposed within the first portion. The second plunger assembly is movably disposed within the second portion. The biasing member is disposed between the first plunger assembly and the second plunger assembly. The biasing member is configured to bias each of the first plunger assembly and the second plunger assembly towards a closed position.