A steering device includes: a steering shaft; a transmitting mechanism configured to transmit the rotation of the steering shaft to a steered wheel; a power cylinder; a rotary valve configured to selectively supply a hydraulic fluid to the pair of the fluid chambers in accordance with the rotation of the steering shaft; and an electric motor configured to provide a rotation force through a speed reduction device to the steering shaft, the steering shaft including a first shaft connected to the steering wheel, and a second shaft connected to the first shaft, and configured to output the rotation force inputted from the first shaft, to the transmitting mechanism side, and the electric motor being connected through the speed reduction device to the second shaft.

The invention relates to a power steering assembly for a hydraulic power steering system of motor vehicles, comprising at least one hydraulic servo valve with a control member (3) for controlling the steering assistance in accordance with a relative rotation of an input shaft with respect to an output shaft (2), and at least one actuator (9) for the relative adjustment of the control member (3) with respect to the input shaft or output shaft (2) in order to influence the steering assistance characteristic. Further, the power steering assembly comprises a summation gearing having a first rotatable drive member (4) that is in operative engagement with the control member (3), and a second rotatable drive member (5) that is in operative engagement with an output element (8) of the actuator (9), and an output member (6). The summation gearing superposes a rotation of the first drive member (4) with a rotation of the second drive member (5) and drives, via the output member (6), an epicyclic gearing with at least one planetary gear (11), which is in operative engagement together with both the input shaft or output shaft (2) and with the control member (3) and can be rotated both about a planetary axis (14) fixed with respect to the frame and about its own axis of rotation (12) orbiting about the planetary axis (14), in such a way that a rotation of the first drive member (4) causes a rotation of the own axis of rotation (12) of the planetary gear (11) orbiting about the planetary axis (14) in such a way that no rotation of the planetary gear (11) about its own axis of rotation (12) occurs as a consequence, but a rotation of the second drive member (5) causes a rotation of the planetary gear (11) about its own axis of rotation (12), wherein the rotation of the planetary gear (11) about its own axis of rotation (12) causes a relative rotation of the input shaft or output shaft (2) with respect to the control member (3).

A control assembly (20) for overcoming a rotational resistance required to activate supplementary steering force associated with conventional power steering systems. The control assembly (20) includes a shaft (26) subject to rotational resistance via a torsion bar (62). A valve assembly (22) has a first hydraulic circuit (76) that is interchangeable from an unassisted condition (36) to an assisted condition (34) for providing supplementary steering force to a steering gear after the rotational resistance of the torsion bar (22) is overcome by rotating the shaft (26). An actuator (38) includes a second hydraulic circuit (86) interchangeable from an unengaged condition (42) to an engaged condition (40) applying circumferential force on the shaft (26) to overcome the rotational resistance of the torsion bar (62) and rotate the shaft (26) from a non-rotated position thereby activating the supplementary force of the first hydraulic circuit (76).

A control assembly (20) for overcoming a rotational resistance required to activate supplementary steering force associated with conventional power steering systems. The control assembly (20) includes a shaft (26) subject to rotational resistance via a torsion bar (62). A valve assembly (22) has a first hydraulic circuit (76) that is interchangeable from an unassisted condition (36) to an assisted condition (34) for providing supplementary steering force to a steering gear after the rotational resistance of the torsion bar (22) is overcome by rotating the shaft (26). An actuator (38) includes a second hydraulic circuit (86) interchangeable from an unengaged condition (42) to an engaged condition (40) applying circumferential force on the shaft (26) to overcome the rotational resistance of the torsion bar (62) and rotate the shaft (26) from a non-rotated position thereby activating the supplementary force of the first hydraulic circuit (76).

A steering device includes: a steering mechanism including a steering shaft, and a transmitting mechanism; and a controller including a first hydraulic passage state judging section, a first electric motor control section, and a second electric motor control section; the first hydraulic passage state judging section configured to judge a state of the hydraulic fluid in a first hydraulic passage in which the hydraulic fluid discharged from the first pump flows, the first electric motor control section configured to control and drive the first electric motor based on a driving state of a vehicle, and the second electric motor control section configured to increase a rotation number of the second electric motor when the first hydraulic passage state judging section judges that a supply of the hydraulic fluid in the first hydraulic passage is deficient.

A steering device includes: a steering mechanism including a steering shaft, and a transmitting mechanism; and a controller including a first hydraulic passage state judging section, a first electric motor control section, and a second electric motor control section; the first hydraulic passage state judging section configured to judge a state of the hydraulic fluid in a first hydraulic passage in which the hydraulic fluid discharged from the first pump flows, the first electric motor control section configured to control and drive the first electric motor based on a driving state of a vehicle, and the second electric motor control section configured to increase a rotation number of the second electric motor when the first hydraulic passage state judging section judges that a supply of the hydraulic fluid in the first hydraulic passage is deficient.

A steering device includes a control unit that includes a hydraulic abnormality determiner. The hydraulic abnormality determiner is configured to determine a hydraulic abnormality to be present in a pair of liquid chambers of a power cylinder of the steering device, in response to satisfaction of a condition that a total torque of a steering torque measured by a torque sensor and a motor assist torque provided by an electric motor is greater than a predetermined threshold torque. The control unit is configured to increase the motor assist torque in response to satisfaction of a condition that the hydraulic abnormality determiner determines the hydraulic abnormality to be present.

A steering device includes a control unit that includes a hydraulic abnormality determiner. The hydraulic abnormality determiner is configured to determine a hydraulic abnormality to be present in a pair of liquid chambers of a power cylinder of the steering device, in response to satisfaction of a condition that a total torque of a steering torque measured by a torque sensor and a motor assist torque provided by an electric motor is greater than a predetermined threshold torque. The control unit is configured to increase the motor assist torque in response to satisfaction of a condition that the hydraulic abnormality determiner determines the hydraulic abnormality to be present.

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.