GB1578924A

GB1578924A - Vehicle steering system

Info

Publication number: GB1578924A
Application number: GB975176A
Authority: GB
Original assignee: TRW Steering Systems Ltd
Current assignee: TRW Steering Systems Ltd
Priority date: 1977-02-22
Filing date: 1977-02-22
Publication date: 1980-11-12

Description

(54) A VEHICLE STEERING SYSTEM (71) We, CAM GEARS LIMITED, a British Company, of Wilbury Way, Hitchin, Hertfordshire SG4 OTU, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a vehicle steering system, and is a modification of the invention described in our co-pending Patent No. 1,409,367, hereinafter referred to as the main Patent.

Claim 1 of the main Patent is directed to a vehicle steering system comprising a pinion rotatable by a steering column, a toothed sector engaged with and rotatable by the pinion, and a steering linkage for effecting movement of steerable road wheels, the steering linkage including a first member pivotally connected to the sector at some chosen radius from the axis of rotation of the sector and pivotally connected to a subsequent member borne for substantially translational motion in response to rotation of the sector.

According to the present invention there is provided a vehicle steering system as claimed in claim 1 of the main Patent, and wherein the subsequent member is coupled to two spaced levers which are themselves each coupled to a tie rod of a respective steerable road wheel, whereby said substantially translational motion of the subsequent member effects rotation of both levers to move the steerable road wheels through the tie rods.

Preferably each lever is coupled to the subsequent member and the respective tie rod on opposite sides of its pivot axis. However, alternatively, both the tie rod and the subsequent member may be coupled on the same side of each lever, for example with the subsequent member coupled between the tie rod coupling and the pivot axis of an elongate lever. Conveniently, the pivot axis of each lever will extend vertically.

One embodiment of a vehicle steering system in accordance with the invention will now be described by way of example only, with reference to the accompanying drawing which is a schematic plan view of the system.

Referring to the drawing, a vehicle steering system comprises a toothed sector 2 in engagement with a pinion 4 mounted on one end of a vehicle steering column 6. A transverse coupling rod 8 is connected through a ball joint to the sector at a chosen radius from its axis of rotation. The rod 8 constitutes part of the vehicle steering linkage and is pivotally connected at its other end to a track rod 22 extending generally laterally of the vehicle whereby rotation of the vehicle steering wheel moves the coupling rod 8 to effect translational movement of the track rod 22. The rod 8 is shown coupled to the central region of the track rod 22. At each end, the track rod 22 is coupled to a respective one of two idler levers 18 pivotally mounted at their central regions one on either side of a central vehicle engine block (shown in chain-dotted lines) which lies between the steerable road wheels 16. Each idler lever 18 is pivotally connected at one end to the track rod 22 and at its other end to its respective tie rod 20. Each tie rod 20 is connected through wheel levers 14 to a respective vehicle steerable road wheel 16.

In operation, rotation of the vehicle steering wheel produces a corresponding rotation of the sector 2 causing mainly translational movement of the intermediate track rod 22 through the coupling rod 8 to pivot the idler levers 18 thereby turning the steerable road wheels 16. The tie rods 20 are connected to the idler levers 18 on or near the common axis of the steerable road wheels 16 in the straight-ahead condition. Further, the pivotal coupling of the coupling rod 8 and the track rod 22 is conveniently centrally of the vehicle (i.e. on the longitudinal centrc line thereof) when the stecrable road wheels 16 are in the straight-ahead condition.

Although the idler levers 18 are shown as operating in a horizontal plane, these levers could be arranged to operate in, for example, a vertical plane. Similarly, the sector 2 could be inclined from the illustrated vcrti cal plane to lie, for example, in a plane normal to the steering column 6.

WHAT WE CLAIM IS: in claim 1 of the main Patent, and wherein the subsequent member is coupled to two spaced levers which are themselves each coupled to a tie rod of a respective steerable road wheel, whereby said substantially translational motion of the subsequent member effects rotation of both levers to move the steerable road wheels through the tie rods.

2. A vehicle steering system as claimed l. A vehicle steering system as claimed in claim 1 in which each lever is coupled to the subsequent member and the respective tie rod on opposite sides of its pivot axis.

3. A vehicle steering system as claimed in claim l or claim 2 in which the pivot axis of each lever extends vertically.

4. A vehicle steering system substantially as herein described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

the vehicle (i.e. on the longitudinal centrc line thereof) when the stecrable road wheels

16 are in the straight-ahead condition.

Although the idler levers 18 are shown as operating in a horizontal plane, these levers could be arranged to operate in, for example, a vertical plane. Similarly, the sector 2 could be inclined from the illustrated vcrti cal plane to lie, for example, in a plane normal to the steering column 6.

WHAT WE CLAIM IS: in claim 1 of the main Patent, and wherein the subsequent member is coupled to two spaced levers which are themselves each coupled to a tie rod of a respective steerable road wheel, whereby said substantially translational motion of the subsequent member effects rotation of both levers to move the steerable road wheels through the tie rods.
2. A vehicle steering system as claimed l. A vehicle steering system as claimed in claim 1 in which each lever is coupled to the subsequent member and the respective tie rod on opposite sides of its pivot axis.
3. A vehicle steering system as claimed in claim l or claim 2 in which the pivot axis of each lever extends vertically.
4. A vehicle steering system substantially as herein described with reference to the accompanying drawing.