Koyo Seiko Company, Ltd.

Masayoshi Ashitaka

Kazuhiro Watanabe

Osamu Sano

Akihiko Shiina

Toshiaki Oya

Yasuhiro Kamatani

Yoshimi Kotake

Takashi Ohata

Ryouichi Tokioka

Katsuyuki Oguchi

Hiroji Ueda

In a hydraulic power steering apparatus, when the relative rotation between input and output shafts which are connected by a torsion bar is converted into the relative rotation between an outer valve element and an inner valve element, the ratio of the relative rotation angle of the latter to the relative rotation angle of the former is varied in accordance with an operating condition of a vehicle. The hydraulic pressure to generate steering assist force is controlled in accordance with the relative rotation angles between both valve elements. The outer valve element is capable of relative coaxial rotation to the input and output shafts, and the inner valve element is formed integrally with the input shaft. A swinging member is supported by first, second and third supporting parts which respectively rotate together with the input shaft, the output shaft or the outer valve element. One of the first, second and third supporting parts is displaced in the axial direction by a certain distance in accordance with the operating condition of the vehicle.

Hydraulic power steering apparatus

Growing community of inventors

Katuragi, Japan

Masayoshi Ashitaka