Koyo Seiko Company, Ltd.

Gates Unitta Asia Company

Jtekt Corporation

Hiroto Sasaki

Kunihiro Oka

Takehiro Saruwatari

Kensaku Nakamura

Akihiro Hironaka

Kazuaki Nagamatsu

Hiroshi Murataka

Atsuya Miyata

Osamu Sano

Tetsuya Murakami

Yasuhiro Tomago

Masanobu Inoue

An electric power steering apparatus includes a speed reducing mechanism for decelerating the rotation of a rotatable shaft in an electric motor and a converting mechanism for converting the output rotation of the speed reducing mechanism into the axial movement of a steering shaft extending toward the right and left sides of a vehicle. The speed reducing mechanism includes an input pulley driven by the electric motor, an output pulley arranged with the steering shaft enclosed thereby, a belt for connecting the input pulley and the output pulley to each other, and a belt tension adjuster.

Electric power steering apparatus

An electric power steering apparatus includes a speed reducing mechanism for decelerating the rotation of a rotatable shaft in an electric motor and a converting mechanism for converting the output rotation of the speed reducing mechanism into the axial movement of a steering shaft extending toward the right and left sides of a vehicle. The speed reducing mechanism includes an input pulley driven by the electric motor, an output pulley arranged with the steering shaft enclosed thereby, a belt for connecting the input pulley and the output pulley to each other and a belt tension adjuster.

An electric power steering apparatus includes a rolling bearing for supporting rotatably a worm that is rotated by a steering assisting electric motor ; a first resilient portion which is disposed in contact with the inner circumference of an inner ring of the rolling bearing and held on the worm so that it is extendable by a force in an axial direction applied to the worm ; and two resilient members and , held in contact with both ends of the inner ring , for restraining the movement of the worm in the axial direction. Even when the electric power steering apparatus has a single rolling bearing, the worm is moved in the axial direction by a steering force transmitted to the worm from a worm wheel in a steering range in which the motor is not driven, and the steering load in the steering range in which the motor is not driven is decreased.

A screw member is screwed into a spool which is axially movably inserted into a housing. The opening of the throttling portion of a variable throttle valve is varied according to the axial shifting of the spool according to the rotation of the screw member. The centerline of the screw member is eccentric to the centerline of the spool. The eccentricity prevents the spool from rotating together with the screw member.

Variable throttle valve with eccentric members, for use in hydraulic

The hydraulic control valve 30 of a hydraulic actuator 20 for generating steering assist force comprises a first valve member 31 and a second valve member 32, both of which are rotatable relative to each other in response to steering resistance. Throttling portions are formed of spaces between axially extending edges defined by slots of the first valve member and axially extending edges defined by slots of the second valve member. The first hydraulic oil outlet slot 51b is located between a right turn slot 50a and a left turn slot 50b. The second hydraulic oil outlet slot 51c is located between communication slots 50c. Hydraulic oil feed slots 51a are located between a right turn slot 50a and a communication slot 50c and between a left turn slot 50b and a communication slot 50c. A closing angle of at least one type of second group throttling portions A', B', C' and D' is set larger than a closing angle of each of a first group throttling portions A, B, C and D. A variable throttle valve 60, capable of varying the flow area of its own throttling portion in response to driving conditions, is disposed between the second group throttling portions A', B', C' and D' and the tank 71.

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Nara, Japan

Hiroto Sasaki