Koyo Seiko Company, Ltd.

Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Yoshimi Kotake

Kazuhiro Watanabe

Akihiko Shiina

Osamu Sano

Toshiaki Oya

Yasuhiro Kamatani

Takashi Ohata

Ryouichi Tokioka

Tatsuro Motoyama

Masayoshi Ashitaka

Katsuyuki Ooguchi

Takashi Oohata

Hiroji Ueda

Katsuyuki Oguchi

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

A control valve controls hydraulic pressure of oil supplied to a hydraulic actuator for generating steering assist power, based on elastic relative rotation between input and output shafts. A restricting device restricts relative rotation between input and output shafts based on a driving condition of the vehicle, and adjusts the hydraulic pressure for pressing the input shaft via a plunger inserted into a guide bore formed in the output shaft, based on the driving condition of the vehicle by the hydraulic pressure adjustment mechanism. The plunger is guided by the inner circumference of the guide bore along the direction that the plunger approaches to and goes away from the output shaft when the input and output shafts relatively rotate. A friction reducing element is interposed between the inner circumference of the guide bore and the outer circumference of the plunger.

A device comprising a cylinder and a piston slidably fitted therein and having a metal piston ring attached to its outer periphery. The cylinder has a recess in each of a plurality of portions thereof dividing the inner periphery of the cylinder circumferentially thereof and opposed to the piston ring when the piston is brought close to each of its opposite stroke ends, the recess having a width smaller than the width of fit of the piston to the cylinder. The piston has a recess corresponding to the recess in the cylinder inner periphery and formed in each of a plurality of portions of the piston in the vicinity of the piston ring and diving the outer periphery of the piston circumferentially thereof. The cylinder has two oil chambers formed on the respective opposite sides of the piston and adapted to communicate with each other through the cylinder recess and the piston recess upon the piston being brought close to each stroke end.

Hydraulic power steering device

Growing community of inventors

Kashiba, Japan

Yoshimi Kotake