A hydraulic steering unit (1) is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path (2) and a tank port (T) connected to a tank flow path (3), a working port arrangement having a left working port (L) connected to a left working flow path (4) and a right working port (R) connected to a right working flow path (5), a bridge arrangement (7) of variable orifices having a first left orifice (A2L) connected to the main flow path (2) and to the left working flow path (4), a first right orifice (A2R) connected to the main flow path (2) and to the right working flow path (5), a second left orifice (A3L) connected to the left working flow path (4) and to the tank flow path (3), and a second right orifice (A3R) connected to the right working flow path (5) and to the tank flow path (3). Such a hydraulic steering unit should not have a self-alignment but a comfortable feeling for the driver. To this end a variable diagonal orifice A11_12 1 a variable diagonal orifice (A11_12) is connected to the main flow path (2) and to the tank flow path (3), wherein the orifices of the bridge arrangement (7) are closed in neutral position and the diagonal orifice (A11_12) is open in neutral position.

A hydraulic steering unit (1) is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path (2) and a tank port (T) connected to a tank flow path (3), a working port arrangement having a left working port (L) connected to a left working flow path (4) and a right working port (R) connected to a right working flow path (5), a bridge arrangement (7) of variable orifices having a first left orifice (A2L) connected to the main flow path (2) and to the left working flow path (4), a first right orifice (A2R) connected to the main flow path (2) and to the right working flow path (5), a second left orifice (A3L) connected to the left working flow path (4) and to the tank flow path (3), and a second right orifice (A3R) connected to the right working flow path (5) and to the tank flow path (3). Such a hydraulic steering unit should not have a self-alignment but a comfortable feeling for the driver. To this end a variable diagonal orifice A11_12 1 a variable diagonal orifice (A11_12) is connected to the main flow path (2) and to the tank flow path (3), wherein the orifices of the bridge arrangement (7) are closed in neutral position and the diagonal orifice (A11_12) is open in neutral position.

The present invention is to provide a vehicle-mounted apparatus having a biasing structure using a coil spring capable of reducing a lateral force of a coil spring that is applied to a biasing target member. When N1, n1, N0, and n0 represent the number of effective turns when the relief valve spring 37 is set in a valve hole 34 of a spool 29 in a compressed state, a value of an integer of N1, the number of effective turns when a length of the relief valve spring 37 is a natural length, and a value of an integer of N0, respectively, the spring 37 satisfies an equation 1: 0N1n10.25 or an equation 2: 0.75N1n1<1.

A steering device for a steerable machine, particularly a construction machine, comprising a steering element for manual input of steering commands, a steering actuator for driving a steering adjustment of a travel unit of the construction machine, and a transmission device, which is arranged between the steering element and the steering actuator, the transmission device including an actuator orbitrol for driving the steering actuator. Furthermore, the invention relates to a construction machine having such a steering device, as well as to a method for steering a steerable machine, particularly a construction machine.

A steering device for a steerable machine, particularly a construction machine, comprising a steering element for manual input of steering commands, a steering actuator for driving a steering adjustment of a travel unit of the construction machine, and a transmission device, which is arranged between the steering element and the steering actuator, the transmission device including an actuator orbitrol for driving the steering actuator. Furthermore, the invention relates to a construction machine having such a steering device, as well as to a method for steering a steerable machine, particularly a construction machine.

An articulated work vehicle with linked front and rear frames includes a joystick lever, a force imparting component, and a controller. The joystick lever can be moved to an inside or an outside with respect to an operator's seat by being operated by an operator, to change a steering angle of the front frame with respect to the rear frame. The force imparting component is configured to impart an assist force or a counterforce to an operation of the joystick lever by the operator. The controller controls the force imparting component so that an operating force required to move the joystick lever to the outside is different from an operating force required to move the joystick lever to the inside.

An articulated work vehicle with linked front and rear frames includes a joystick lever, a force imparting component, and a controller. The joystick lever can be moved to an inside or an outside with respect to an operator's seat by being operated by an operator, to change a steering angle of the front frame with respect to the rear frame. The force imparting component is configured to impart an assist force or a counterforce to an operation of the joystick lever by the operator. The controller controls the force imparting component so that an operating force required to move the joystick lever to the outside is different from an operating force required to move the joystick lever to the inside.

A vehicle steering assist system, including an engine pump, a flow-rate restricting mechanism, a motor pump, a motor-pump controller, and a steering-force assist device, wherein the steering assist system is configured to restrict an engine-pump ejection flow rate to be lower than a required receiving flow rate to be received by the assist device when the engine pump is operated by being driven by an engine rotating at an idling speed, the engine-pump ejection flow rate being a flow rate of a working fluid ejected from the engine pump to the assist device via the restricting mechanism, and wherein the motor-pump controller is configured to control a motor-pump ejection flow rate such that an insufficient flow rate of the working fluid is covered by the motor-pump ejection flow rate, the insufficient flow rate being a shortage in the required receiving flow rate not covered by the engine-pump ejection flow rate.

A vehicle steering assist system, including an engine pump, a flow-rate restricting mechanism, a motor pump, a motor-pump controller, and a steering-force assist device, wherein the steering assist system is configured to restrict an engine-pump ejection flow rate to be lower than a required receiving flow rate to be received by the assist device when the engine pump is operated by being driven by an engine rotating at an idling speed, the engine-pump ejection flow rate being a flow rate of a working fluid ejected from the engine pump to the assist device via the restricting mechanism, and wherein the motor-pump controller is configured to control a motor-pump ejection flow rate such that an insufficient flow rate of the working fluid is covered by the motor-pump ejection flow rate, the insufficient flow rate being a shortage in the required receiving flow rate not covered by the engine-pump ejection flow rate.

A steering assist system for a hybrid vehicle capable of being driven by both of an engine and a drive motor, including a first assist portion and a second assist portion configured to assist a steering force respectively utilizing the engine and an electric motor each as a drive source, wherein the steering force is assisted only by the second assist portion in a motor-driven state in which the vehicle is driven only by the drive motor, and wherein the steering assist system is configured to, upon occurrence of a failure of the second assist portion in the motor-driven state, drive the engine, execute assist switching from an assist by the second assist portion to an assist by the first assist portion, and gradually increase, in the assist switching, an assist force by the first assist portion up to a set assist force when the vehicle is being steered.