Provided is a power steering device capable of causing control that uses a pump device and control that uses an electric motor on an input shaft to cooperate with each other. The power steering device includes a power cylinder including a pair of hydraulic chambers partitioned by a piston and configured to generate a steering assist force for a steered wheel, a pump device configured to be driven through control by a first electric motor and configured to discharge working fluid, a rotary valve configured to selectively supply the working fluid supplied from the pump device to the pair of hydraulic chambers in accordance with relative rotation between the input shaft and the output shaft, a second electric motor provided so as to surround at least a part in an axial direction of the input shaft and configured to control the rotation of the input shaft, and a second electric motor control part installed in a control device and configured to output a control signal for controlling driving of the second electric motor based on a revolution number signal of the first electric motor.

Provided is a power steering device capable of causing control that uses a pump device and control that uses an electric motor on an input shaft to cooperate with each other. The power steering device includes a power cylinder including a pair of hydraulic chambers partitioned by a piston and configured to generate a steering assist force for a steered wheel, a pump device configured to be driven through control by a first electric motor and configured to discharge working fluid, a rotary valve configured to selectively supply the working fluid supplied from the pump device to the pair of hydraulic chambers in accordance with relative rotation between the input shaft and the output shaft, a second electric motor provided so as to surround at least a part in an axial direction of the input shaft and configured to control the rotation of the input shaft, and a second electric motor control part installed in a control device and configured to output a control signal for controlling driving of the second electric motor based on a revolution number signal of the first electric motor.

Technical solutions for compensating for lash in a steering system are described. An example method includes determining a rack pressure value based on a driver torque value and a differential pressure across a rack of the steering system. The method also includes determining a compensation friction value based on a position of a handwheel of the steering system and a speed of a vehicle equipped with the steering system. The method also includes computing a pressure value based on the rack pressure value and the compensation friction value. The method also includes generating a torque command using the pressure value, the torque command being added to the driver assist torque for the steering system.

Power steering device has steering mechanism 2, power cylinder 29 having a pair of hydraulic chambers 29a, 29b divided by piston 31 and providing steering force to steering mechanism, torque sensor 11 detecting steering torque Tr of steering mechanism, rotary valve 30 selectively supplying working fluid supplied from pump 9 to the pair of hydraulic chambers according to relative rotation between input and output shafts, hollow shaft motor 10 providing steering force to input shaft, control unit 13 in which microcomputer is mounted, and torque command signal operating section 61 provided in control unit and configured to calculate torque command signal Tm* for driving and controlling electric motor 10 on the basis of the steering torque Tr and vehicle speed Vs and when vehicle speed is a predetermined vehicle speed or greater, set torque command signal to 0. With this, physical size of power steering device can be decreased.

The invention relates to a method for compensating a stick-slip effect in the case of a recirculating ball steering system (20) having a steering housing (22), in which a steering piston (24) is supported between a first working chamber (34) and a second working chamber (36), wherein the steering piston (24) has a toothed region (26) on the steering-piston outer wall of the steering position, with which toothed region teeth (28) of a segment shaft (30) mesh, the steering piston (24) can be moved along a longitudinal axis X-X, the working chambers (34, 36) are connected to a control valve (39) by means of pressure-medium lines in order to provide steering assistance, the control valve (39) is connected to a processor unit (40), by means of which valves of the control valve (39) can be actuated, and the processor unit (40) is connected to a sensor (42), which determines rotation of the steering column both in a first direction of rotation and in a second, opposite direction of rotation. When a rotational motion of the steering column in a first direction occurs and thereafter the rotational motion in said direction nearly or completely stops, the valves of the control valve (39) are opened by the processor unit (40) in such a way that the pressure in the working chamber (34, 36) of the steering piston (24) facing away from the direction of motion of the steering piston (24) is reduced and immediately thereafter the pressure in the same working chamber (34, 36) is increased again.

A fluid controller (1), in particular as part of a hydraulic steering unit, is described, said controller (1) comprising a housing (2) having a supply port arrangement, a sleeve (4) arranged rotatably in a bore of the housing (2), a spool (3) arranged rotatably in the sleeve (4), and a measuring motor, wherein the measuring motor comprises a plurality of working chambers, each working chamber being connected to the bore, wherein the sleeve (4) comprises a commutation geometry (7) having a number of pairs of commutation grooves (12, 13) and controlling together with a housing geometry (5) of the housing (2) a flow of hydraulic fluid into and out of the working chambers and the spool (3) comprises a spool geometry controlling together with a valve geometry of the sleeve (4) a flow of hydraulic fluid between the supply port arrangement and the commutation geometry. Such a fluid controller should have a stable control behaviour. To this end at least one of the commutation grooves (12, 13) comprise a closed bottom and at least one of the commutation grooves (12, 13) comprise a throughgoing opening (10, 11) forming part of the valve geometry.

A method for determining a driver torque of a power steering assembly for an electrohydraulic power steering system of motor vehicles, includes an input shaft for introduction of a driver torque, an output shaft for driving a steering linkage and a torsion bar between the input shaft and the output shaft for actuation of a rotary slide valve, an electric drive for electrical steering assistance, and a control unit for controlling the electric drive. The power steering assembly has a sensor arrangement on the torsion bar for actuation of the rotary slide valve. An actual torque is determined with the aid of the sensor arrangement. The control unit determines a driver torque with the aid of the actual torque.

A method for determining a driver torque of a power steering assembly for an electrohydraulic power steering system of motor vehicles, includes an input shaft for introduction of a driver torque, an output shaft for driving a steering linkage and a torsion bar between the input shaft and the output shaft for actuation of a rotary slide valve, an electric drive for electrical steering assistance, and a control unit for controlling the electric drive. The power steering assembly has a sensor arrangement on the torsion bar for actuation of the rotary slide valve. An actual torque is determined with the aid of the sensor arrangement. The control unit determines a driver torque with the aid of the actual torque.

This power steering valve (1) includes a sleeve (40), a spool (60) held in such a way as to be able to rotate within the housing (40), to which an input shaft U of a steering wheel S is coupled, a gerotor (30) fixed to the sleeve (10) and configured to be driven by hydraulic fluid which flows out from the predetermined opening of the sleeve (40), and a drive shaft (80) meshing with an inner rotor (32) of the gerotor (30) and pivotally supported in a swingable manner by the sleeve (40) with use of a pin (81), wherein an overall length Ld of the drive shaft (80) is formed to have a dimension defined by (?).Math.Ls?Ld?(?).Math.Ls relative to an overall length Ls of the sleeve (40), and the pin (81) is arranged at a position nearer the gerotor (30) in an axial direction than a middle position in the sleeve (40).

This power steering valve (1) includes a sleeve (40), a spool (60) held in such a way as to be able to rotate within the housing (40), to which an input shaft U of a steering wheel S is coupled, a gerotor (30) fixed to the sleeve (10) and configured to be driven by hydraulic fluid which flows out from the predetermined opening of the sleeve (40), and a drive shaft (80) meshing with an inner rotor (32) of the gerotor (30) and pivotally supported in a swingable manner by the sleeve (40) with use of a pin (81), wherein an overall length Ld of the drive shaft (80) is formed to have a dimension defined by (?).Math.Ls?Ld?(?).Math.Ls relative to an overall length Ls of the sleeve (40), and the pin (81) is arranged at a position nearer the gerotor (30) in an axial direction than a middle position in the sleeve (40).