A work vehicle includes steerable left and right front wheels and steerable left and right rear wheels and a manually operated steering input for steering the wheels through a hydraulic steering circuit connected to left and right front hydraulic actuators configured to steer the left and right front wheels. In order to perform a rear wheel alignment operation, the hydraulic steering circuit is bypassed so that the steering wheel can be used as an input device to steer each of the rear wheels in a steer by wire arrangement for alignment, without steering the front wheels during the alignment process.

The present disclosure is directed to an agricultural tractor. In an agricultural tractor according to the present disclosure, a steering unit is coupled to a coupling target in a power supply room. According to the present disclosure, the efficiency of the assembly of a cabin and a transmission is maintained, and also vibration and noise are reduced in a boarding space.

A hybrid steering system for a vehicle includes a mechanical linkage, configured to connect a steering wheel of the vehicle to steerable wheels of the vehicle; a steering assister, connected to the mechanical linkage and configured to apply a first torque to the mechanical linkage to assist steering of the steerable wheels; a hydraulic system, distinct from the steering assister, connected to the mechanical linkage and commutable between an activated configuration, in which the hydraulic system applies a second torque to the mechanical linkage to assist steering of the steerable wheels, and a disabled configuration, in which the hydraulic system does not apply the second torque to the mechanical linkage; and a pneumatic system, connected to the hydraulic system and configured to pressurize the hydraulic system when the hydraulic system is in the disabled configuration.

A hybrid steering system for a vehicle includes a mechanical linkage, configured to connect a steering wheel of the vehicle to steerable wheels of the vehicle; a steering assister, connected to the mechanical linkage and configured to apply a first torque to the mechanical linkage to assist steering of the steerable wheels; a hydraulic system, distinct from the steering assister, connected to the mechanical linkage and commutable between an activated configuration, in which the hydraulic system applies a second torque to the mechanical linkage to assist steering of the steerable wheels, and a disabled configuration, in which the hydraulic system does not apply the second torque to the mechanical linkage; and a pneumatic system, connected to the hydraulic system and configured to pressurize the hydraulic system when the hydraulic system is in the disabled configuration.

A power steering system has a power steering control system configured to control the power steering system, a first power steering pump configured to be driven by a propulsion source of the vehicle, a second power steering pump configured to be driven by the rotation of the wheels of the vehicle. The first power steering pump is a controllable pump operatively connected to the power steering control system and the power steering control system is configured to control said first power steering pump. The first and second power steering pump are connected to a common power steering fluid circuit such that said first and second power steering pump can operate in parallel to simultaneously provide power steering assistance.

A power steering system has a power steering control system configured to control the power steering system, a first power steering pump configured to be driven by a propulsion source of the vehicle, a second power steering pump configured to be driven by the rotation of the wheels of the vehicle. The first power steering pump is a controllable pump operatively connected to the power steering control system and the power steering control system is configured to control said first power steering pump. The first and second power steering pump are connected to a common power steering fluid circuit such that said first and second power steering pump can operate in parallel to simultaneously provide power steering assistance.

A method for operating a steering unit for a commercial vehicle includes a step of transfer or operation of a regulator unit of the steering unit of the commercial vehicle in an inactive operating mode if it is recognized that a driver is not giving a steering requirement and if a vehicle velocity of the commercial vehicle is lower than a predefined threshold value. The method further includes a step of activation of the regulator unit of the steering unit in an active operating mode if it is recognized that the driver is giving a steering requirement or if a vehicle velocity of the commercial vehicle exceeds the predefined threshold value.

A method for operating a steering unit for a commercial vehicle includes a step of transfer or operation of a regulator unit of the steering unit of the commercial vehicle in an inactive operating mode if it is recognized that a driver is not giving a steering requirement and if a vehicle velocity of the commercial vehicle is lower than a predefined threshold value. The method further includes a step of activation of the regulator unit of the steering unit in an active operating mode if it is recognized that the driver is giving a steering requirement or if a vehicle velocity of the commercial vehicle exceeds the predefined threshold value.