Nissan Motor Company Limited

Megumu Higuchi

Tokiyoshi Yanai

Hirotsugu Yamaguchi

Koichi Takahashi

Yutaka Aoyama

Moritsune Nakata

Masafumi Nakayama

Yasuji Shibahata

Kunihiko Morikawa

Minoru Watanabe

In order to simplify the construction of a power steering system and simultaneously allow for unassisted steering in the event that the motor or the like of the system malfunctions, the differential gear which establishes the drive connection between the auxiliary motor, the steering input shaft and the steering output shaft is such that when the element of the differential gear which is connected to a variable speed motor is not driven by the motor, an essentially 1:1 drive is established between the steering input and output shafts while at this time the motor driven element is braked only by the friction and other natural resistances which occur in the system. Further, the differential gear is such as to have a relatively low responsiveness to the rotational speed of the motor and thus eliminates the need for a reduction gear between the motor and the differential gear.

Steering system for automotive vehicle or the like

An input shaft and an output shaft can rotate relative to each other. Pressure supplied to a pressure-responsive actuator depends on the axial position of a movable valve member. A transmission arrangement serves to move the valve member only in the axial direction as the input and output shafts rotate relative to each other. The valve member and each of the input and output shafts are wholly outside one another.

Power steering system

In a vehicle the steering system includes a steering gear housing transversely mounted relative to the vehicle body by means of a plurality of gear housing mount insulators. Each of the gear housing mount insulators elastically supports the gear housing in such a manner as to allow transverse displacement of the gear housing with respect to the vehicle body. A damper is provided to restrain the transverse displacement allowed by the gear housing mount insulators.

Steering system controlling transverse displacement of a gear housing

In a method of manufacturing a rack for a variable ratio rack and pinion steering gear, having a preforming process for preparing a rack blank having a plurality of teeth which are formed to a shape corresponding approximately to the shape desired in the finished rack and a finishing process for converting the teeth to the finished shape by cold forming in a die having a shape which is the exact counterpart of the finished shape, the preformed rack teeth are shaped to have top lands which are level with those in the finished shape and bottom lands that are deeper than those of same. The rack teeth in the preformed shape are all wider at the top areas than in the finished shape, and the ratio of the widths at the root areas of the rack teeth in the preformed shape to those in the finished shape varies in proportion to the variation of the steering ratio such that a rack tooth for a higher steering ratio is given the above-mentioned ratio that is larger.

Method of manufacturing racks for variable ratio steering gears

In accordance with the present invention, there is provided a novel and improved varibale ratio rack and pinion steering gear wherein the pinion has teeth of variable shape and size and the rack has teeth of variable shape and size. The teeth of the pinion are correctly meshable with a uniformly shaped rack profile and adapted to provide variable pitch circles. The teeth of the rack are generated by using the profile of the pinion teeth in a manner to provide a varying gear ratio even when the steering angle is larger than 180.degree..

Variable ratio rack and pinion steering gear

An operating valve assembly for a power steering unit comprises inner and outer sleeves in sliding contact with each other and relatively rotatable in response to the twisting of a torsion bar corresponding to a steering load. The outer sleeve is formed in its inner circumferential surface with a plurality of recesses circumferentially spaced apart and having circular opening edges, which recesses are alternately connected to a pump and a drain chamber. The inner sleeve is formed in its outer circumferential surface with grooves establishing communication between adjacent ones of the aforesaid recesses. The outer sleeve is formed with apertures opening into the respective grooves, with the apertures being alternately connected to one or the other of the power cylinder chambers. The operating valve assembly is inexpensive and easy to manufacture.

Operating valve assembly for a power steering

A rotary-motion directional fluid-flow control valve comprising an inner valve element rotatable about an axis therethrough and formed with concavities in its outer peripheral wall, an outer valve body rotatable about an axis aligned with the axis of rotation of the valve element and circumferentially slidable on the outer peripheral surface of the valve element, and plug members which are closely fitting in radial holes formed in the valve body and including a first plug member solid in its entirety and a second plug member formed with an axial bore, the first and second plug members being in registry with the concavities in the valve element in radial directions of the valve body depending upon the relative angular positions of the valve body and element. The valve may be advantageously use in a power-assisted steering system of an automotive vehicle.

Growing community of inventors

Tokyo, Japan

Megumu Higuchi