Abstract: 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.

Abstract: 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.

Abstract: A power steering unit capable of finely controlling the steering assistance power generated by a hydraulic actuator in accordance with the steering direction and driving condition without requiring a complex structure is provided at low cost. The right steering assistance power generating state or the left steering assistance power generating state can be alternatively selected by switching the flow path of hydraulic fluid to the hydraulic actuator 10 for generating the steering assistance power with a motor-operated switching valve 23. The switching valve 23 is controlled so that the steering assistance power acts in accordance with the determined steering direction, and an electric motor 22 for driving a pump 21 is controlled so that the pressure of the hydraulic fluid discharged from the pump 21 is varied in accordance with the determined driving condition.

Abstract: 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.

Abstract: The control valve of the hydraulic power steering apparatus controls hydraulic pressure of the oil supplied to the hydraulic actuator for generating steering assist power, in accordance with the amount of elastic relative rotation between the input and output shafts. The restricting device restricting the relative rotation between the input and output shafts in accordance with a driving condition of the vehicle adjusts the hydraulic pressure for pressing one of the input and output shaft via the plunger inserted into the guide bore formed in the other of the input and output shaft, in accordance with the driving condition of the vehicle by means of the hydraulic pressure adjustment mechanism. The plunger is guided by the inner circumference of the guide bore to the direction in which the plunger approaches to and goes away from the other of the input and output shaft when the input and output shafts relatively rotate.

Abstract: 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.

Abstract: A power steering apparatus includes a motor 5 connected through a clutch 6 and a worm gear mechanism 50,51 with a steering column 12. A multi-lead strap 46 is wound around the steering column within a first cylindrical housing 23 for electrically connecting a torque sensor 4 to terminals disposed outside the steering column. The worm gear mechanism includes a worm wheel 50 fitted on the steering column in the first housing, and a worm shaft 51 in mesh with the worm wheel and disposed in a second cylindrical housing 54 adjacent the first housing. The second housing has one end closed and the other end open. The worm shaft is rotatably supported at one end by a first bearing 52 press fitted in the closed end of the second housing and at its other end, which is connected with the clutch, by a second bearing 53 fixedly mounted thereon, such that the worm shaft can be axially removed from the second housing through its open end.