FR2503072A1 - Rack operated steering for motor vehicle - has parallel links between rack and steering ball joint - Google Patents

Abstract

The rack operated steering is for a car suspension with a telescopic support leg (1) between the stub axle support (12) and the vehicle body and a lower arm (8). Each end of the rack (24) is lengthened axially by a lever (23), rigidly fixed to it. This carries two pivots (21,22) of thrust rods (19,19'), fixed at different levels to a control arm (16) of the steering lever (14) of the stub axle support. The pivots (17,18) on this control arm are each aligned with the suspension ball joint (15).

Description

Rack steering system
The invention relates to a rack-and-pinion steering device in which a rack and pinion is driven by a pinion secured to the steering shaft and is connected to the wheel control rods.

The invention relates more particularly to the mode of installation of a rack-and-pinion steering device of the aforementioned type in an area which usually requires the use of specific steering members intended to avoid any contact with the peripheral elements of the chassis during geometric modifications of the direction and suspension drawings.

The invention also relates to a rack-and-pinion steering device of the type comprising a rack housing, a rack movable axially in said housing, a set of control rods arranged axially at the ends of the rack, functionally connected to the steering wheel stub axles.

According to the invention, each end of the rack is extended axially by a lever rigidly connected to the latter and which carries two articulations of substantially parallel thrust rods secured at different levels of a control arm of the orientation lever of the wheel stub axle whose joints on said control arm are respectively aligned with the ball joint of the arm to the orientation lever.

The steering device thus produced is particularly suitable for the front axles of motor vehicles which have a telescopic strut disposed between the stub axle and the vehicle body and a lower suspension arm.

Other characteristics and advantages will emerge from the appended drawing in which the figure is a perspective view of a half-train with telescopic strut disposed between the stub axle and the bodywork.

Referring to the figure, it can be seen that the train comprises a telescopic strut 1 constituted by the shock absorber, articulated at its upper part on the body by a flexible articulation not shown and at its lower part on a triangulated arm 8, which carries an elastic articulation 9 movable around a horizontal axis 11.

The suspension function is ensured, in the case of figure, by a helical spring 2 bearing on the body and on a cup fixed to the strut 1, but could also be by a torsion bar blocked on the axis It solidarisant the lower arm 8 and the body, or any other suspension element.

The connection of the wheel to the half-train is effected by means of a wallet 12 of which a branch 6 is rigidly fixed to the body of the shock absorber serving as a strut 1. The stub axle 12 also carries an arm guide 7 to which the tail of a suspension ball joint 5 is connected, the housing of which is connected to the transverse suspension arm 8.

The stub axle 12 also carries an orientation lever 14 of the wheel as is well known.

The orientation lever 14 carries a steering ball joint 15 which links the steering knuckle 12 to the steering mechanism on which a control arm i6 is articulated and which is aligned with two elastic articulations 17, 18.

The control arm 16 carries at two different levels elastic joints 17, 18 of two thrust rods 19, 19 'one end of which is secured by means of equally elastic joints 22, 21 of a lever 23 rigidly linked to the rack 24 and having no relative movement relative to the latter.

It can thus be seen that the rack 24 can be placed without any particular difficulty at a level compatible with the arrangement of the various members of the chassis and that all the members 23, 19, 19 ′ and 16 replace a very long steering rod whose movements could be hindered by certain parts of the vehicle
It is further noted that the deflections of the transverse lower arm and of the strut have no influence on the position of the rack.

Another advantage of the device lies in the fact that it is possible to easily define the law of variation of pinching or opening of the wheel.

 It should be noted that the description only describes half of the telescopic strut train. The invention relates of course to the arrangement of a set of two levers such as 23 which extend axially each end of the rack and which are rigidly connected thereto.

Claims (1)

CLAIM 1. rack-and-pinion steering device, in particular for the front axle of a motor vehicle which comprises a telescopic strut (1 'arranged between the knuckle (12) and the vehicle body and an inner arm (8), characterized by the fact that each end of the rack (24) is extended axially by a lever (23) rigidly connected thereto which carries two articulations (21, 22) of thrust rods (19, 19 '), integral at different levels d 'a control arm (16) of the orientation lever' 4 'of the wheel stub axle (12), whose articulations (17, 18) on said control arm (16) are respectively aligned with the suspension ball joint (15).