An electromechanical dual steering system for a utility vehicle includes two steering systems, each having a drive unit for actuating one steering linkage each for wheels of the utility vehicle. Each drive unit has an electric motor. The dual steering system has a main power supply for supplying the electric motors with energy. The electromechanical dual steering system is characterized in that the dual steering system has at least one emergency power supply for supplying at least one electric motor with energy in the event that the main power supply fails.

A method includes determining whether a multiphase electric machine is unstable. The method also includes, in response to a determination that the multiphase electric machine is unstable, setting a gate voltage of a first three terminal semiconductor switch to zero. The method also includes, in response to a determination that the multiphase electric machine is stable, setting the gate voltage of the first three terminal semiconductor switch to nonzero. The method also includes, in response to the first three terminal semiconductor switch being set to zero, increasing electrical conduction from one phase of the multiphase electric machine to another phase of the multiphase electric machine. The method includes, in response to the first three terminal semiconductor switch being set to nonzero, increasing electrical resistance from the one phase of the multiphase electric machine to the another phase of the multiphase electric machine.

A steering system for a trailing axle of a motor vehicle includes an electric motor, a hydraulic pump, a first valve, and a working cylinder. The electric motor is configured to drive the hydraulic pump. The working cylinder has a central bore and a piston positioned in the working cylinder. The first valve is fluidically connected to the pump such that the first valve is configured to block flow between the central bore and the pump in response to pressure generated by the pump, and to release the flow in response to a non-pressurized state of the pump in order to divert hydraulic fluid from the working cylinder through the central bore via an adhesion-driven movement of the piston into a central position in the central bore. A method includes operating a steering system for a trailing axle of a motor vehicle of this type.

A self-centering double ended hydraulic steering cylinder that uses no electronics and a method of making the same. The self-centering double ended hydraulic steering cylinder has an elongated housing having end caps at opposing ends of the housing, wherein first and second rod portions are slidably disposed through the end caps. A piston is slidably disposed within the housing, the first and second rod portions extending from the piston, the piston defining first and second hydraulic fluid chambers within the housing. On each opposing end cap is a coiled spring for urging the piston toward a neutral position with the housing. A miniscule passage is formed into the piston so that hydraulic fluid flow through the piston that allows the springs to push the piston back to the neutral position.

An electrical method for centering telehandler rear wheels preferably includes an electronic control module (ECM), a rear steering cylinder, a pair of rear centering valves, a front steering cylinder, a steer mode valve, at least one steering position sensor, a steering control unit and a mode selection switch. The front and rear steering cylinders are connected to the steer mode valve. The steering control unit directs hydraulic fluid from a hydraulic pump to flow into the front and rear steering cylinders to turn the wheels. A 2W steering mode requires that the rear wheels be straight before going from a 4W steering mode into the 2W steering mode. The ECM monitors a position of the rear wheels through the at least one steering position sensor. If the wheels are not straight, the ECM will open a centering valve to straighten the rear wheels, before going into the 2W steering mode.

Provided is an electric power steering device including: a front-wheel steering mechanism, which is provided to front wheels of a vehicle, and includes a front-wheel steering motor as a drive source; and a rear-wheel steering mechanism, which is provided to rear wheels of the vehicle, and includes a rear-wheel steering motor as a drive source, wherein the rear-wheel steering motor is configured to be a double-inverter three-phase duplex motor, the double-inverter three-phase duplex motor including two three-phase windings and two inverters each configured to individually drive one of the two three-phase windings. Therefore, the electric power steering device is capable of, even when a failure has occurred in the steering motor of the rear-wheel steering mechanism, maintaining a function of the rear-wheel steering mechanism to secure behavior stability of the vehicle.

A technology of mechanically classifying a switching operation between a traveling mode and a special moving mode is provided to prevent a mode switching misoperation. A traveling mode switching mechanism of a four-wheel independent steering type vehicle includes a shift gate which is disposed by forming a moving path of a shift lever, and grouping a traveling mode and a special moving mode. Additionally, a mode switching differentiation devices differentiates a mode switching operation of a driver by configuring so that an operation of the shift lever switched between the traveling mode and the special moving mode is physically different from an operation of the shift lever switched between the traveling modes or between the special moving modes.

A steering system for a trailing or leading axle of a vehicle includes a steering angle sensor for measuring a steering angle of wheels of a front axle of the vehicle, a driving speed sensor for measuring a driving speed of the vehicle, an electric motor that drives a hydraulic pump, and a working cylinder connected to the hydraulic pump for steering the wheels of the trailing axle. The system also includes a control device that determines a trailing angle of wheels on the trailing axle of the vehicle and actuates the electric motor in a corresponding manner. The working cylinder has a center position borehole via which hydraulic fluid is released from the working cylinder. A piston closes the center position borehole in the straight-ahead position of the wheels of the trailing axle. The center position borehole can only be closed by a piston seal of the piston.

A steering system for a steerable vehicle includes at least two steerable wheels, to each of which an electrically operable steering actuator to enable the steering actuator to adjust the steering angle of the particular steerable wheel by application of a steering torque. The at least two steering actuators can be mechanically coupled to each other so that, in the event of a failure or a malfunction of the one steering actuator, the steering torque provided by the other steering actuator can be transferred to the one steering actuator, to enable the steering angle of the steerable wheel assigned to the failed steering actuator to still be changed via the other steering actuator. The at least two steering actuators can be mechanically coupled to each other via a bendable shaft or via a universal joint shaft which includes at least two rigid shafts hingedly connected via a universal joint.

A method for operating a steering mechanism (12) of a motor vehicle, wherein a steering rod (27) can be held or displaced along its longitudinal axis (a) by an electric motor (22) so that the wheel steering angle (8, 9) of at least one wheel (5, 6) on at least one vehicle axle (1) can be maintained or changed. When a force (F.sub.ext) acts essentially axially on the steering rod (27), displacement of the steering rod (27) is at least inhibited by a detent torque (RM) of the electric motor (22) and/or by a self-induced torque (M.sub.sip) of the electric motor. The invention also relates to a device for carrying out the method and to a steering mechanism, which is preferably in the form of a steer-by-wire steering system. A control unit is provided for carrying out the method.