GB2321627A

GB2321627A - Vehicle steering column

Info

Publication number: GB2321627A
Application number: GB9701823A
Authority: GB
Inventors: Laurence George Herbert Barton; Michael Thomas Hancock
Original assignee: Nastech Europe Ltd
Current assignee: Nastech Europe Ltd
Priority date: 1997-01-29
Filing date: 1997-01-29
Publication date: 1998-08-05
Anticipated expiration: 2017-01-29
Also published as: DE19803200B4; GB2321627B; DE19803200A1; GB9701823D0; FR2758782A1

Abstract

A vehicle steering column includes an elongate inner shaft or tube (3) supported by angular contact ball bearings (7A, 7B) in an outer tube (4). To take up system tolerances in the steering column assembly and pre-load the bearings with minimum pre-load, a wedge mechanism (2) is provided between a yoke (1) and the inner shaft or tube adjacent one of the bearings (7A), the wedge mechanism (2) having two wedge faces (2B, 2C) each provided with an arcuate array of radially extending serrated teeth (9), the wedge faces being inclined in a common plane out of right angles to the longitudinal axis of the inner member (3). To pre-load the bearings, the wedge mechanism (2) is ratcheted into an expanded mode.

Description

1 VEHICLE STEERWG COLUMN 2321627 This invention relates to a vehicle

steering column.

is A typical steering column comprises an inner elongate member (shaft or tube) and an outer elongate member in the form of a tube surrounding the inner member, there being bearings supporting the outer tube on the inner shaft or tube. Such an arrangement ordinarily comprises an upper steering column portion.

When using two angular contact ball bearings, the bearings are springloaded in order to pre-load the bearings to hold the inner tube or shaft in position but at the same time to keep the bearing force as low as possible so that the bearing friction is at a minimum. However, this arrangement can allow the steering shaft to be moved by the driver when the steering wheel is pulled. Such movement of the steering wheel is not normally desirable.

According to the present invention, there is provided a vehicle steering column having an inner elongate member and an outer elongate member surrounding the inner member with bearings supporting the inner member in the outer member, the bearings being loaded by a wedge mechanism incorporated in the steering column.

The wedge mechanism can comprise two opposed, contacting wedge face portions which are mounted about an axis of the inner member so as to be relatively rotatable to one another to expand the wedge mechanism to load the bearings.

is The contacting wedge faces of the portions can be serrated so as positively to lock the wedge mechanism when the faces are relatively rotated in a direction to load the bearings of the wedge face portions, the serrations extending substantially radially around at least part of an arc of a circle concentric with the axis of the inner member.

The wedge faces of the wedge face portions can each be formed on the end face of a respective nut, by which means the wedge faces can be relatively rotated.

Each wedge face can comprise two wedge face regions; alternatively, each wedge face can comprise three wedge face regions equi-spaced around an arc of a circle.

The wedge mechanism can be located adjacent a steering column yoke and a lower end of the inner elongate member remote from the steering wheel, one wedge face portion being joined to the inner elongate member and the other wedge face portion can be joined to a portion of the yoke.

The invention also extends to a vehicle incorporating a steering column as defined above.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in Which:- Figure 1 is a diagrammatic sectional side view of a vehicle steering column incorporating means to load mounting bearings, Figure 2 is a diagrammatic side view illustrating the loading means in the form of a wedge mechanism and an adjacent portion of the steering column in a pre-adjusted or pre-bearing-loaded position, is Figure 3 is a view similar to Figure 2 but showing the wedge mechanism in an adjusted or bearing-loaded position, Figure 4 is an end view of part of the wedge mechanism viewed along the line IV-1V of Figure 2, and Figure 5 is an end view of the part of the wedge mechanism shown in Figure 5 as viewed along line V-V of Figure 3.

Referring to the drawings, an upper end of a vehicle steering column is shown, which includes, proceeding from a lower end to an upper end thereof, a yoke 1, which is joined to a wedge mechanism 2, which itself is joined to a lower end of an elongate member in the form of an inner shaft 3, upon an upper end 3A of which is provided a means for connection of a steering wheel (not shown). Coaxially surrounding the greater length of the inner shaft 3 is an outer tube 4 which is secured in use to upper and lower fixing brackets 5, 6, respectively.

The inner shaft 3 is rotatably mounted within the outer tube 4 through the intermediary of angular contact ball bearings 7A and 7B. The axially uppermost end of the bearing 7B abuts a circlip 8 fitted about the inner shaft 3. The axially lowermost end of the inner shaft 3, beyond the adjacent end of the outer tube 4, is joined to a first wedge face portion 2A of the wedge mechanism, the first wedge face portion 2A having an end wedge face 2B, which 4 itself is in facing contact with a wedge face portion 2C of a second wedge face portion 2D.

The two wedge faces 2B and 2C are each provided with an arcuate array of radially-extending serrated teeth 9. As seen best in Figure 1, the two wedge faces 2B and 2C are inclined in a common plane out of right angles to the longitudinal axis of the inner shaft 3.

is The wedge face portions 2A, 2D are each formed as a nut, by which means the wedge faces 2B, 2C can be relatively rotated.

The wedge mechanism 2 therefore replaces the previously-known spring loading of the bearings by providing two serrated wedge adjusters (2A, 2D) that can be rotated relatively to each other in notched increments. The arrangement will take up system tolerances in the steering column assembly and pre-load the bearings 7A, 7B with no end play or excessive internal force (minimun pre-load). Accordingly, when a driver applies a force to the steering wheel, there should be no detectable movement. At least two wedge faces can be provided; in the drawings, three wedge faces on each wedge portion are shown.

To assemble the components, the wedge portions 2A and 2D of the wedge mechanism 2 are fitted on the inner shaft 3 in a minimum adjustment position. The inner shaf t 3 is then passed through the angular contact ball bearings 7A and 7B and then the circlip 8 is fitted to retain the inner shaft 3 in position. By using the nuts of the wedge portions 2A and 2D, the serrated wedge mechanism 2 is ratcheted into an expanded mode until it pre-loads the bearings 7A, 7B. The steering column system is then loaded and this condition is retained by the serrated teeth 9. The wedge mechanism 2 or parts thereof, can be of plastics material or metal.

Claims

CLAIMS:

1. A vehicle steering column having an inner elongate member and an outer elongate member surrounding the inner member with bearings supporting the inner member in the outer member, the bearings being loaded by a wedge mechanism incorporated in the steering column.

2. A vehicle steering column according to claim wherein the wedge mechanism comprises two opposed, contacting wedge face portions which are mounted about an axis of the inner member so as to be relatively rotatable to one another to expand the wedge mechanism to load the bearings.

3. A vehicle steering column according to claim 2, wherein the contacting wedge faces of the portions are serrated so as positively to lock the wedge mechanism when the faces are relatively rotated in a direction to load the bearings of the wedge face portions, the serrations extending substantially radially around at least part of an arc of a circle concentric with the axis of the inner member.

4. A vehicle steering column according to claim 2 or 3, wherein the wedge faces of the wedge face portions are each formed on the end face of a respective nut, by which means the wedge faces can be relatively rotated.

5. A vehicle steering column according to claim 2, 3 or 4, wherein each wedge face comprises two wedge face regions.

7

6. A vehicle steering column according to claim 2, 3 or 4, wherein each wedge face comprises three wedge face regions equi-spaced around an are of a circle.

7. A vehicle steering column according to any one of claims 2 to 6, wherein wedge faces of the two wedge face portions are inclined in a common plane out of right angles to an axis of the inner elongate member.

8. A vehicle steering column according to any one of the preceding claims, wherein the wedge mechanism is located adjacent a steering column yoke of the steering column member and a lower end of the inner elongate member which is, in use, remote from a steering wheel.

9. A vehicle steering column according to claim 8, wherein one wedge face portion is joined to the inner elongate member and the other wedge face portion is joined to a portion of the yoke.

10. A vehicle incorporating a vehicle steering column according to any one of the preceding claims.

10. A vehicle steering column according to any one of the preceding claims, wherein the bearings are angular contact ball bearings.

11. A vehicle steering column, substantially as hereinbefore described with reference to the accompanying drawings.

12. A vehicle incorporating a vehicle steering column according to any one of the preceding claims.

9 Amendments to the claims have been filed as follows is 1. A vehicle steering column having an inner elongate member and an outer elongate member surrounding the inner member with bearings supporting the inner member in the outer member, the bearings being loaded by a wedge mechanism incorporated in the steering column, the wedge mechanism comprising two opposed, contacting wedge face portions which are mounted about an axis of the inner member so as to be relatively rotatable to one another to expand the wedge mechanism to load the bearings, and the contacting wedge faces of the portions are serrated so as positively to lock the wedge mechanism when the faces are relatively rotated in a direction to load the bearings of the wedge face portions, the serrations extending substantially radially around at least part of an arc of a circle concentric with the axis of the inner member.

2. A vehicle steering column according to claim 1, wherein the wedge faces of the wedge face portions are each formed on the end face of a respective nut, by which means the wedge faces can be relatively rotated.

3. A vehicle steering column according to claim 1 or 2, wherein each wedge face comprises two wedge face regions.

4. A vehicle steering column according to claim 1, 2 or 3, wherein each wedge face comprises three wedge face regions equi-spaced around an arc of a circle.

5. A vehicle steering column according to any one of the preceding claims, wherein wedge faces of the two wedge face portions are inclined in a common plane out of right angles to an axis of the inner elongate member.

61 6. A vehicle steering collunn according to any one of the preceding claims, wherein the wedge mechanism is located adjacent a steering column yoke of the steering column member and a lower end of the inner elongate member which is, in use, remote from a steering wheel.

7. A vehicle steering column according to claim 6, wherein one wedge face portion is joined to the inner elongate member and the other wedge face portion is joined to a portion of the yoke.

8. A vehicle steering column according to any one of the preceding claims, wherein the bearings are ang-ular contact ball bearings.

is 9. A vehicle steering column, substantially as hereinbefore described with reference to the accompanying drawings.