Jidosha Kiki Co., Ltd.

Bosch Braking Systems Co. Ltd.

Unisia Jkc Steering Systems Co., Ltd.

Hirotetsu Sonoda

Tatsuya Fukushima

Yasuyoshi Emori

Naosuke Masuda

Tatsuya Harada

Seiichi Kojima

Naosuka Masuda

A steering damper has a pair of damper portions each including a variable throttle valve for restricting inflow from a power cylinder into a flow passage change-over valve, the variable throttle valve provided on the way to each cylinder passage and a first check valve for permitting inflow from the flow passage change-over valve into the power cylinder, the check valve connected in parallel with the variable throttle valve. The steering damper has a second check valve in communication to a tank between the first check valve and left and right chambers of the power cylinder.

Steering damper

A steering damper has a flow passage control valve for switching and connecting among a pump, a tank and left and right chambers in a power cylinder in correspondence to a steering operation, and left and right cylinder passages ( ) for connecting to the left and right chambers. The steering damper is provided with left and right damper portions ( A, B) having variable throttle valves ( ) arranged in the middle of the respective cylinder passages and limiting an inflow to the flow passage control valve from the power cylinder and pilot operated check valves ( ) connected thereto in parallel and allowing an inflow from the flow passage control valve to the power cylinder. A pilot plunger ( ) arranging them at positions close to the respective passages and sliding between the left and right damper portions is provided. Respective end portions of the pilot plunger are set to a pressure receiving surface for receiving the respective fluid pressure by being faced within the left and right cylinder passages and an operating surface for opening the pilot operated check valve in another passage by being operated by the fluid pressure within one cylinder passage.

In a power steering device, a pump supplies a pressure fluid. A power cylinder has left and right chambers and is driven in accordance with a pressure difference between a pressure fluid supplied to the left chamber and that to the right chamber. A flow channel selector valve selectively switches a supply direction of the pressure fluid from the pump to the chambers of the power cylinder in response to steering operation of a steering wheel. Fluid paths connect the flow channel selector valve and the corresponding chambers of the power cylinder to each other. Variable restrictors are disposed in the fluid paths, respectively, to control flow rate of the pressure fluid from the power cylinder to the flow channel selector valve. Check valves are respectively connected to the fluid paths in parallel to the corresponding variable restrictors to prevent a flow of the pressure fluid from the power cylinder to the flow channel selector valve. First and second check valves are opened when the fluid pressure in the right and let fluid paths, respectively, is high.

Power steering device

A rack-pinion type power steering apparatus includes a cylindrical stub shaft, a torsion bar, a pinion shaft, a rotor, and a sleeve. The stub shaft rotates in a steering body upon a steering operation. The torsion bar has one end fixed at one end of the stub shaft and extends toward the other end of the stub shaft. The pinion shaft is pivotally connected to the other end of the torsion bar and has pinion teeth that mesh with a rack of a steering wheel. The rotor is arranged to cover the torsion bar from the stub shaft along an extending direction of the torsion bar. The sleeve has one end integrally connected to the pinion shaft, extends from the pinion shaft along the stub shaft, and is arranged around the rotor to constitute a rotary type channel selector valve between the rotor and the sleeve. At least two ends of an inner circumferential portion of the sleeve integrally connected to the pinion shaft have slidable contact surfaces that slidably support the rotor integrally connected to the stub shaft. A bearing is arranged at either one of the two ends of the sleeve.

Rack-pinion type power steering apparatus

A ball bearing includes a rotary member, an outer ring, and a plurality of balls. Part of the rotary member serves as an inner ring. The outer ring is fitted on an outer circumferential portion of the inner ring. The plurality of balls are incorporated in ball holding grooves between the inner and outer rings. At least one of the inner and outer rings has a stepped portion in a circumferential surface thereof close to the ball holding grooves. The stepped portion prevents positional shift of the balls incorporated through a gap between the inner ring and the outer ring set eccentric with respect to the inner ring. A method of assembling a ball bearing is also disclosed.

Ball bearing and method of assembling the same

A rack-pinion type power steering apparatus includes a cylindrical stub shaft, a torsion bar, a pinion shaft, a rotor, and a sleeve. The stub shaft rotates in a steering body upon a steering operation. The torsion bar has one end fixed at one end of the stub shaft and extends through the stub shaft toward the other end of the stub shaft. The pinion shaft is pivotally connected to the other end of the torsion bar. The rotor is arranged to cover the torsion bar from the stub shaft along an extending direction of the torsion bar. The sleeve has one end integrally connected to the pinion shaft, extends from the pinion shaft along the stub shaft, and is arranged around the rotor to constitute a rotary type channel selector valve between the rotor and the sleeve. The pinion shaft is axially supported by the steering body at two end portions of the sleeve.

A hydraulic reaction force apparatus for a power steering system includes input and output shafts, guide holes, balls, a reaction force reception portion, a hydraulic reaction force chamber, and a reaction force piston. The output shaft is coaxial with the input shaft, the output shaft and the input shaft being rotatable relative to each other. The guide holes axially extend through a flange formed on one of the input and output shafts. The balls are axially slidable in the guide holes, respectively. The reaction force reception portion is formed on the other one of the input and output shafts so as to oppose one major surface of the flange. The reaction force reception portion is adapted to receive the balls. The hydraulic reaction force chamber is formed on the other major surface of the flange which opposes its one major surface. The reaction force piston is slidably coaxial with the input and output shafts in the hydraulic reaction force chamber. The reaction force piston is adapted to urge the balls against the reaction force reception portion to generate a restriction force corresponding to a reaction force hydraulic pressure between the input and output shafts.

Hydraulic reaction force apparatus for power steering system

A power steering device having a fluid pressure cylinder of a single rod type providing like output characteristics for steering both rightwardly and leftwardly. A rod-side chamber and a head-side chamber of the fluid pressure cylinder have different pressure receiving areas. A control valve controls the changeover of a flow path among a pump, a tank and the rod-side and head-side chambers in accordance with the movement of a steering wheel such that the rod-side chamber is connected to the pump and the tank is connected to the head-side chamber when the piston is to be moved toward the head-side chamber, and the pump is connected to both the head-side chamber and the rod-side chamber when the piston is to be moved toward the rod-side chamber.

Growing community of inventors

Saitama, Japan

Hirotetsu Sonoda