Koyo Seiko Company, Ltd.

Koyo Jidoki Kabushiki Kaisha

Koyo Auto-mech. Co., Ltd.

Osamu Sano

Hirofumi Matsuoka

Toshihiko Daido

Kunihiro Oka

Shigetaka Kinme

Masahide Nakamura

Masanori Kobayashi

Hiroto Sasaki

Shigehisa Matsushita

Ryuichi Komine

Yasuhiro Ishii

Kazuhiro Watanabe

Yoshitomo Tokumoto

Mitsuhiko Nishimoto

Akihiko Shiina

Hirokazu Arai

Toshiaki Oya

Susumu Imagaki

Takatoshi Sakata

Takehiro Saruwatari

Kensaku Nakamura

Hideo Matsubara

Takeo Iino

Atsuya Miyata

Yoshimi Kotake

Yasuhiro Kamatani

Tatsuhiro Yamamoto

Yoshio Ito

Tatsuo Otsuka

Yoshikazu Ikegi

Ryouichi Tokioka

Takashi Ohata

Hiroji Ueda

Katsuyuki Oguchi

Masayoshi Ashitaka

Tomoyuki Takei

Koichi Natsunari

An electric power steering apparatus in which steering assistance is achieved by transmitting a rotary motion of an electric motor for steering assistance to a steering shaft on which a worm wheel is mounted through a worm shaft on which a worm is mounted, wherein the worm shaft is deflectable toward the worm wheel and equipped with a biasing member biasing the worm shaft in the deflective direction thereof, or alternatively, the worm wheel is deflectable toward the worm shaft and equipped with a biasing member biasing the worm wheel in the deflective direction thereof.

Electric power steering apparatus

The present invention provides a hydraulic control valve and a power steering apparatus using the same in which chamfer portions are provided only on throttle portions between oil supply chambers and first oil feed chambers and between the oil supply chambers and second oil feed chambers, or only throttle portions between oil discharge chambersand the first oil feed chambers and between the oil discharge chambersand the second oil feed chambers. With this design, even if six or more oil grooves of each of a valve body and a valve spool are disposed at equal distances from one another, when the minimum flow rate to be controlled is reduced as small as possible, a distribution amount for one portion where the flow rate is controlled can be doubled as compared with a conventional structure, it is possible to stabilize the hydraulic characteristics in a region where the flow rate to be controlled is minimum, and to eliminate the discontinuity of the hydraulic characteristics.

Hydraulic control valve and power steering apparatus using the same

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

In a vehicle steering apparatus, a rotating cylinder supported by a rack housing is threadingly engaged via rolling elements with a screw shaft integrated with a rack which meshes with a pinion which rotates by steering operation. The rotating cylinder is driven by a motor. All of the rolling elements are arranged between a rack support member which supports the rack in the position where the rack is meshed with the pinion, and a support body that is arranged in the movement range of the screw shaft and is capable of supporting the outer circumference of the screw shaft. Loads acting on the rack from the road surface are received by the support body and the rack support member.

Vehicle steering apparatus

A steering assist system which transmits the rotation of an electric motor to a steering shaft via a worm shaft and a worm wheel meshed with a worm of the worm shaft, where an output shaft of the electric motor and the worm shaft are interconnected via a joint. The joint includes a cylindrical first transmission member mounted on the output shaft, a cylindrical second transmission member to which the worm shaft is mounted, and a cylindrical elastic body interposed between the first and second transmission members. The joint may further include a torque limiter including a spring which is interposed between an end surface of the second transmission member and a spring seat formed at an end surface of a third transmission member in opposed relation with the end surface of the second transmission member for inhibiting relative rotation between the second and third transmission members.

Joint and a steering assist system using the same

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.

An electric power steering apparatus in which a shaft of a worm interlocking with rotation of a motor for steering assistance is movable in a radial direction, a pressing body for pressing the worm toward a worm wheel is provided, and the pressing body is provided with a V-shaped contact portion to abut in two circumferential positions of the shaft and an annular elastic body for restricting movement of the pressing body in a direction crossing the radial direction.

A power steering apparatus comprises a rotary cylinder supported with its movement in the axial direction restrained and rotated coaxially with the steering shaft by the force a transmitted from the motor for assisting steering, a plurality of feed rings held eccentrically in said rotary cylinder with their axial centers in parallel, and an engaging groove formed spirally around the outer circumference of the steering shaft for engaging with the projections provided circumferentially on the inner surfaces of the respective feed rings. With this arrangement, it becomes possible to convert the rotation of the motor into the movement in the axial direction of the steering shaft. Thus, this power steering apparatus has a low noise power transmission mechanism with a simple structure.

Power steering apparatus

Two of the three feed rings to beheld in a rotating cylinder are fitted into respective mounting holes, which are formed on both end of the rotating cylinder so as to have circular openings, and are fixed by locking rings so as not to slip off. The center feed ring is fitted into a mounting portion, which is formed at a predetermined position on a circumferential wall of the rotating cylinder so as to have a slit-shaped opening, and is engaged with a thread groove formed on a rack shaft which pierces through an axial center of the rotating cylinder. Moreover, a bearing is fitted inside the rotating cylinder. The bearing is brought into contact with a circumference of the rack shaft so as to stand a radial load applied to the rack shaft. Such a structure realizes firm engagement between the feed rings and moving shaft, and thus a movement transforming device, which has a simple and compact structure capable of secure movement transformation between rotational movement and linear movement.

Movement transforming device and power steering apparatus

The hydraulic pump has a rotor which rotates together with an input shaft linked with an automobile's engine, and generates a hydraulic pressure to be applied to a hydraulic actuating apparatus on the automobile. The hydraulic pump also has a transmission unit provided between a rotating shaft of the rotor and the input shaft so as to change a transmission ratio therebetween, and a hydraulic clutch which changes the transmission unit by means of the hydraulic pressure generated at a discharge side of a pump main body so as to apply the pressure to the apparatus. Therefore, the transmission according to an operating state of the apparatus and a rotational speed of the engine can be realized with a simple constitution and no requirement for a sensor for detecting a running state and a controller for controlling according to the detection.

Hydraulic pump

A servo valve for a power assisted steering gear for producing an auxiliary steering force corresponding to twist between an input member and an output member which are connected to each other by a torsion bar is disclosed. There is provided a sleeve member surrounding a torsion bar and having first and second ends. The first end is prevented from being rotated with respect to the torsion bar. The second end is provided with an opening extending along the radius of the sleeve member. A plunger-containing hole extending in the radial direction is formed in an intermediate part between opposite ends of the torsion bar, and plungers are contained in the containing hole which are movable forward and backward. The plungers are urged forward by a helical compression spring interposed between the plungers. Each of the urged plungers is engaged with an edge of the opening serving as a holding arrangement, to increase the torsional rigidity of the torsion bar at the time when the valve is neutral.

Servo valve for power assisted steering gear

A stepless speed changing apparatus is disclosed that has movable bodies to move in the radial direction of an input shaft, wherein stepless speed reduction is achieved with a simple configuration by converting the movement of the movable bodies into the movement of a speed change ring, and is capable of setting an appropriate mode of changing output, rotational speed and providing such a characteristic that the output rotational speed changes in the reverse manner to the change of the input rotational speed.

Stepless speed changing apparatus

A drive train of a steering apparatus for rear wheels of a vehicle transmits a driving force of a rotary motor to a steering shaft of rear wheels that is shiftable in the axial direction. The drive train comprises a reduction mechanism driven by the motor and a converting mechanism driven by the reduction mechanism for converting rotational motion of the motor to a linear motion for steering the rear wheels. The reduction mechanism includes a worm driven by the motor and a worm wheel driven by the worm. The converting mechanism comprises a trapezoidally-threaded screw mechanism including a trapezoidally-threaded female screw member and trapezoidally-threaded male screw member. One of the trapezoidally-threaded male and female screw members is driven by the worm wheel, and the other fixed to the steering shaft of rear wheels. A transmission efficiency of an input from the steering shaft of rear wheels to the trapezoidally-threaded screw mechanism is set to be zero. It is preferable to provide a backlash adjusting mechanism for adjusting a backlash of the trapezoidally-threaded screw mechanism.

Drive train used in a steering apparatus for rear wheels of a vehicle

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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Kashihara, Japan

Osamu Sano