A turning system is configured to move a turning shaft to turn a left wheel and a right wheel of a vehicle. The turning shaft is configured to couple the left wheel and the right wheel to each other. A torsion bar is engaged with the turning shaft via a steering gear box. The turning system includes: a turning mechanism including (i) an electric turning mechanism including an electric motor configured to rotate a portion of the torsion bar which is located upstream of the steering gear box and (ii) a hydraulic turning mechanism configured to apply a moving force to the turning shaft in an axial direction, the moving force being produced by a hydraulic pressure; and an electric-motor controller configured to control the electric motor based on a frictional force in the turning mechanism and a road-surface reaction force that acts between (a) a tire on the left wheel and a tire on the right wheel and (b) a road surface.

A steering gear apparatus (2) for a motor vehicle (1), comprising a hydraulic steering gear (11) and an electromechanical actuator (7) which is configured to actuate a working valve (10) of the hydraulic steering gear, it being possible for hydraulic fluid to be conducted out of a fluid reservoir (14) selectively into one of at least two working spaces (12) of the hydraulic steering gear (11) in a manner which is dependent on a position of the working valve (10), the steering gear apparatus (1) having a fallback device (16) which is configured, in particular in emergency operation of the steering gear apparatus (2), to selectively conduct hydraulic fluid into one of the at least two working spaces (12) independently of the position of the working valve (10).

Provided is a working vehicle capable of increasing lifting operation speed of a working device without increasing cost, even when provided with a circuit configuration that prioritizes a steering operation over a working device operation. A wheel loader 1 comprises a priority valve 451 configured to allow hydraulic oil discharged from a hydraulic pump 41 to flow into a steering drive circuit 43 preferentially over a working device drive circuit 44, and further comprises: an electric steering lever 30; a pair of solenoid control valves 34A, 34B configured to control a steering directional control valve 33; and a controller 5. The controller 5 is configured to control the pair of solenoid control valves 34A, 34B so as to limit operation speed of a steering 3 when determining that an engine 40 is in a low idle state and a lift arm 21 is performing a lifting operation.

A steering system for controlling a direction of travel of a work machine includes a steering device controllable by an operator of the work machine. The steering device is coupled to an axle of the work machine for controlling an angular orientation of the wheels. A brake is coupled to the steering device and is controllably applied to apply a first amount of resistance to the steering device. A motor is coupled to the steering device and is controllably activated to apply a second amount of resistance to the steering device. A controller controls the steering system of the work machine in at least a first operating mode and a second operating mode. In the first operating mode, the controller controls the brake between an applied position and an unapplied position, whereas in the second operating mode, the controller controls the motor between an active position and a de-activated position.

A hydraulic steering system, comprising a steering pump and a plurality of digital steering cylinder assemblies Each digital steering cylinder assembly includes a steering cylinder and a digital hydraulic valve configured to selectively communicate a rodless cavity of the steering cylinder with one of the steering pump and a return oil circuit, and communicate a rod cavity of the steering cylinder with the other of the steering pump and the return oil circuit.A controller can be configured to emit a digital pulse signal to a motorand cause the digital hydraulic valve to move towards a first working position or a second working position andA mechanical feedback structure can be configured to be driven by a piston rod of the steering cylinder when the valve core of the digital hydraulic valve moves towards the first working position or the second working position, so as to drive the digital hydraulic valve to return to a neutral position. The system can improve the control precision and the response speed of the steering system.

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.

A valve system includes a valve configured to adjust a flow rate of hydraulic fluid in order to steer a work machine, and a control section configured to determine a command signal sent to the valve. The command signal determines a command flow rate of the hydraulic fluid based on a target flow rate corresponding to an input operation command and a change amount in the target flow rate. The control section is configured to control the change amount according to a magnitude of a reversal operation command when receiving the reversal operation command in order to operate the work machine in a direction opposite to a direction in which steering is operating. A work machine includes the valve system, a front frame, a rear frame, an articulate mechanism rotatably connecting the front frame to the rear frame, and a hydraulic actuator.

In a steering assistance device 1, a steering control unit 74 causes a first auxiliary unit 14 to generate torque with reducing by a predetermined amount and causes a second auxiliary unit 20 to generate torque equal to or less than the decreased predetermined amount, in a case where the first auxiliary unit 14 is able to generate a steering assistance force such that a steering angle of a vehicle can reach a target steering angle determined according to curvature so as to make the vehicle travel in the center of a lane.

A steering system for an agricultural vehicle that includes a steering wheel, a steering wheel sensor operably connected to the steering wheel, a drive selector having a forward position, a neutral position, and a reverse position, an actuating device configured for being operably connected to the steerable wheels of the agricultural vehicle, and an electronic control unit operably connected to the steering wheel sensor, the drive selector, and the actuating device. The electronic control unit is configured for selectively preventing a rotation of the steering wheel from steering the steerable wheels in the neutral position of the drive selector.

A method for operating a steering system for a motor vehicle, wherein the steering system has at least one steering lever and at least one electric motor for shifting the steering lever so as to cause a steering movement in the presence of a steering input, and wherein the electric motor is electrically connected to a current source via cabling. In doing so, it is provided that the electric motor is actuated and an electric current flowing between the current source and the electric motor is measured in order to check an electrical connection between the current source and the electric motor under the condition that there is no steering input present.