A work machine includes a vehicle body, a traveling wheel supported by the vehicle body, an actuator to change a steering angle of the traveling wheel from a neutral angle to left or right, a first steering member, and a controller. The first steering member is operable between a left steering range, a right steering range, and a neutral range. The controller controls the actuator so that the steering angle of the traveling wheel is changed to the left and right at speeds that correspond to operating amounts of the first steering member when the first steering member is positioned in the left and right steering ranges, respectively. The controller controls the actuator so that the steering angle returns to the neutral angle when the first steering member is positioned in the neutral range.

The invention relates to a hydraulic steering device that hydraulically connects a steering cylinder to a supply system, whereby the supply system is hydraulically operatively connectable to the steering cylinder via a steering valve to form a main flow connection and the supply system is hydraulically operatively connectable to the steering cylinder via a flow regulation valve arrangement to form a branch flow connection that circumvents the main flow connection, whereby the flow regulation valve arrangement is triggerable by an electric control unit and the flow regulation valve arrangement comprises valve groups that are triggerable individually, which are respectively connected in the forward flow and return flow of the branch flow connection and a release-shutoff valve is assigned to the flow regulation valve arrangement. It is provided that the release-shutoff valve is connected between the flow regulation valve arrangement and the steering cylinder.

A steer-by-wire assembly includes a steering wheel, a steering column coupled to the steering wheel, and a fluid-flow control mechanism coupled to the steering column, wherein the fluid-flow control mechanism is configured to adjust a torque on the steering column. The fluid-flow control mechanism includes a housing defining a cavity, and a flow control valve in fluid communication with the cavity of the housing. The flow control valve is configured to control a flow of a fluid in the cavity of the housing to adjust the torque on the steering wheel. The fluid-flow control mechanism includes a shaft and a piston coupled to the shaft such that translation of the piston causes the shaft to rotate.

The present invention provides a work machine including a steering device that is very responsive to switching operations. The work machine includes: a proportional solenoid valve for outputting a first pilot pressure oil with a pressure responding to a steering signal; a solenoid valve for outputting a second pilot pressure oil with a predetermined pressure while the steering signal is outputted from the steering device; a switching valve capable of switching to a first state of outputting the first pilot pressure oil to a directional control valve and a second state of outputting the second pilot pressure oil to the directional control valve, while the first pilot pressure oil is outputted from the proportional solenoid valve and the second pilot pressure oil is outputted from the solenoid valve in parallel; and a controller to switch the switching valve from the first state to the second state in a case where a malfunction is detected in a main circuit ranging from the steering device to the directional control valve via the proportional solenoid valve and the switching valve of the first state.

An articulated work vehicle in which front and rear frames are linked includes a joystick lever configured to be operated by an operator, a hydraulic actuator driven by hydraulic pressure, a control valve, a force imparting component, and a controller. The joystick lever is usable to set a target steering angle. The hydraulic actuator performs an articulation to change an actual steering angle of the front frame with respect to the rear frame in response to operation of the joystick lever. The control valve controls flow of fluid supplied to the hydraulic actuator so as to make the actual steering angle coincide with the target steering angle. The force imparting component applies an assisting force or a counterforce to operation of the joystick lever. The controller controls the force imparting component so as to generate resistance to operation of the joystick lever based on a start timing of an articulation.

In one embodiment, a steering system for a harvesting machine, the steering system comprising: a steer-by-wire system, comprising: a first steering mechanism enabling manual steering control of a machine by an operator; a controller configured by instructions to receive signals based on operator movement of the first steering mechanism and, based on the signals, cause a valve of a hydraulic circuit to control a steering cylinder; and a backup mechanical steering system, comprising: a second steering mechanism enabling manual steering control of the machine by the operator, the second steering mechanism mechanically coupled to the valve, the second steering mechanism configured to replace the first steering mechanism based on operator intervention.

A steering system and method is described for a vehicle having steerable front and rear wheels, and a steering input device for receiving manual steering input. Front and rear hydraulic steering devices may be coupled, respectively, to the front and rear wheels. Front and rear valve assemblies may be configured, respectively, to steer the front and rear wheels. In a manual steering mode, the front valve assembly may be disabled with respect to the front steering device, and the front hydraulic steering device may steer the front wheels based upon the manual steering input. In a rear steering assist mode, a rear steering command may be determined based upon the manual steering input, and the rear wheels steered based upon the rear steering command. In an automated steering mode, the front and rear wheels may be automatically steered based upon a target path of travel for the vehicle.

An articulated work vehicle includes a hydraulic actuator, a control valve, a joystick lever, and a first link mechanism. A front frame is linked to a rear frame. The hydraulic actuator is configured to be driven by hydraulic pressure and configured 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 joystick lever is disposed in a cab provided on the rear frame. The joystick lever is configured to be operated by an operator. The first link mechanism is disposed below the cab. The first link mechanism is configured to transmit an operation of the joystick lever to the control valve.

A steering system and method are described for a vehicle having steerable front and rear wheels. A rear hydraulic steering device may be coupled to one or more of the rear wheels. A rear valve assembly may hydraulically control the rear hydraulic steering device to steer the rear wheels based upon a rear steering command. In a rear steering assist mode, the rear steering command may be determined based upon a manual steering input received at a steering input device. In an automated steering mode, the rear steering command may be determined based upon a target path of the agricultural vehicle that is determined independently of the manual steering input.

A hydraulic steering device which hydraulically connects a steering cylinder to a supply system. The supply system is hydraulically operatively connectable to the steering cylinder via a steering assembly for the purposes of forming a main flow connection, and the supply system is furthermore hydraulically operatively connectable to the steering cylinder via a flow regulating valve arrangement, such that a secondary flow connection can be formed which bypasses the main flow connection and via which at least one first working chamber and one second working chamber of the steering cylinder can be supplied independently of one another with hydraulic fluid.