Knorr-bremse Steering System Japan Ltd.

Tatsuo Matsumura

Masaki Watanabe

Power steering device has steering mechanismpower cylinderhaving a pair of hydraulic chambersdivided by pistonand providing steering force to steering mechanism, torque sensordetecting steering torque Tr of steering mechanism, rotary valveselectively supplying working fluid supplied from pumpto the pair of hydraulic chambers according to relative rotation between input and output shafts, hollow shaft motorproviding steering force to input shaft, control unitin which microcomputer is mounted, and torque command signal operating sectionprovided in control unit and configured to calculate torque command signal Tm* for driving and controlling electric motoron 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.

Power steering apparatus

A power steering apparatus includes a steering shaftincluding an input shaft, an intermediate shaftconnected through a first torsion barto the input shaft, and an output shaftconnected through a second torsion barto the intermediate shaft; a hollow motorto provide a rotational force to the intermediate shaft; and a control deviceincluding a microcomputer, and including an output shaft rotation angle presuming sectionto presume an output shaft rotation angle &#x3b8;g based on signals of an input shaft rotation angle &#x3b8;h and an intermediate shaft rotation angle &#x3b8;m, a torsion spring constant gand gof the first and second torsion bars; and a motor drive control sectionto control the hollow motor based on the output shaft rotation angle.

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.

Growing community of inventors

Higashimatsuyama, Japan

Tatsuo Matsumura