GB2304865A

GB2304865A - An adjustable steering column for a vehicle

Info

Publication number: GB2304865A
Application number: GB9518190A
Authority: GB
Inventors: Martin James Holly
Original assignee: MG Rover Group Ltd
Current assignee: MG Rover Group Ltd
Priority date: 1995-09-07
Filing date: 1995-09-07
Publication date: 1997-03-26
Anticipated expiration: 2015-09-07
Also published as: GB2304865B; GB9518190D0

Abstract

The adjustable steering column 1 comprises a first section 4 which is pivotable for adjustment of rake and a second section 3 which is telescopable for adjustment of reach. A motor 15 can transmit drive through a first or a second cone clutch 20 or 22. The cone clutch 20 drives a worm gear 26 which meshes with an arcuate toothed segment 6 on the first section 4. The cone clutch 22 drives a screw-threaded shaft 32 which is operatively engaged within a screw-threaded sleeve 34 on a fixed part 2 of the steering column. The motor 15 and cone clutches 20, 22 form part of an adjustment mechanism 14 which is carried by the second section 3 of the steering column. By selecting the appropriate clutch 20, 22, the motor 15 will adjust the rake or reach of the steering column 1.

Description

AN ADJUSTABLE STEERING COLUMN FOR A VEHICLE This invention relates to a steering column for a vehicle which is adjustable for both rake and reach.

The position of the steering column and hence the steering wheel of a motor vehicle is preferably adjustable to enable different drivers to achieve a comfortable driving position.

Some known steering columns are rotatable about a pivot.

Others have a telescopable portion to enable them to be adjusted for reach. Further known steering columns are independently adjustable for both for rake and reach. In these different types of adjustable steering columns, adjustment may be manually effected or may be motorised.

In the case of motorised adjustment for both rake and reach, known steering columns have an adjustment mechanism comprising two separate motors, one of the motors operating a tilting mechanism and the other moving the steering column in and out relative to the driving seat. Such a mechanism is heavy, bulky and expensive and an object of this invention is to provide an improved adjustable steering column.

According to this invention we provide an adjustable steering column for a vehicle comprising a first section displaceable for adjustment of rake, a second section displaceable for adjustment of reach, a motor, first and second clutches operatively connected to the motor, the first clutch having a driven member for displacing the first section and the second clutch having a driven member for displacing the second section, whereby at any instant either the first clutch or the second clutch may be engaged to enable the required adjustment to be made.

The first section of the steering column is preferably a pivotal section of the steering column and operation of the first clutch pivots the first section to enable the rake to be adjusted.

The second section of the steering column is preferably a telescopable section of the steering column and operation of the second clutch effects telescoping movement thereof to enable the reach to be adjusted.

The driven member associated with the first clutch may drive the first section through gearing. The driven member associated with the second clutch may drive the second section through a screw threaded member. The gearing associated with the first clutch may be arranged to drive a toothed member of the first section about the said pivot. The screw-threaded member associated with the second clutch preferably cooperates with a member attached to a fixed part of the steering column, the screw-threaded member and second clutch being carried by the second section so that operation of the second clutch causes a telescoping movement of the column via the screw thread.

The two clutches are preferably coaxial and may be connected to opposite end faces of a drive element. The drive element may be actuated by the motor via a transmission such as a drive belt.

A gearbox may be provided either in a common casing with the motor or between the motor and the drive element.

Only one gearbox would be required, whereas in a mechanism incorporating two motors, two gearboxes would be needed.

An adjustable steering column in accordance with the invention will now be described by way of example and with reference to the accompanying drawing, which is a side elevation of part of the steering column partially in cross-section.

A steering column 1 has a fixed outer tube 2 and a telescopable inner tube 3. The inner tube 3 has a yoke 4 connected thereto by means of a pivot pin 5 to enable the yoke to be pivoted vertically relative to the inner tube 3. The yoke 4 (constituting the aforesaid first section of the steering column) is formed with an arcuate toothed segment 6 having a centre of curvature corresponding to the axis of pivot pin 5.

A steering shaft indicated generally at 7 comprises an upper section 8 formed with splines 9 for receiving a steering wheel 10 shown in broken outline. The upper section 8 is connected to a telescopable intermediate section 12 via a universal coupling 11 which has a centre of pivoting on the axis of the pivot pin 5. The intermediate section 12 is slidable within a lower section 13 which, at its lower end (not shown), is drivably connected to a steering mechanism such as a rack and pinion of known kind. The intermediate section 12 is suitably splined to the lower section 13 so that rotary movement of the steering wheel 10 will be transmitted to the steering mechanism.

The inner tube 3 (constituting the aforesaid second section of the steering column) carries an adjustment mechanism 14 for the steering column. The adjustment mechanism comprises a single electric motor 15 which drives a pulley 16 via a gearbox 17. The pulley 16 is connected to a drive roller 18 by a belt 19. The drive roller 18 is associated with first and second cone clutches 20, 22. The cone clutch 20 comprises a driving member 23 in the form of a cone coaxial with and operatively connected to the drive roller 18 and a driven member in the form of a cup 24 drivably connected to a worm gear 26. The worm gear 26 meshes with the arcuate toothed segment 6. The cone clutch 22 is of similar construction to the cone clutch 20, having a cone 28 and a cup 30. The cup 30 is drivably connected to a screwthreaded shaft 32.The screw-threaded shaft 32 is operatively engaged within a threaded sleeve 34 fixed to the outer tube 2.

The adjustment mechanism 14 on the inner tube 3 is contained within a housing 35.

To engage the cone clutch 20, the drive roller 18 is shifted upwardly to interengage the cone 23 and cup 24.

To engage the cone clutch 22, the drive roller 18 is moved downwardly to disengage the clutch 20 and interengage the cone 28 and cup 30. It will be appreciated that the first and second clutches 20, 22 are arranged so that either but not both can be engaged at any time. A suitable selector (not shown) is provided for shifting the drive roller 18 to engage one or other of the clutches 20, 22. The same selector is arranged to switch on the motor 15 to transmit drive through the selected clutch.

On engagement of clutch 20, the selector will switch on the motor 15 so as to drive the clutch 20 in one direction or the other depending on the selector position and thereby pivot the steering wheel 10 up or down to adjust rake.

On engagement of clutch 22, the selector will switch on the motor 15 so as to drive the clutch 28 in one direction or the other depending on the selector position and thereby displace the adjustment mechanism and hence the inner tube 3 by rotating the screw threaded shaft 32 in the sleeve 34. Reach is thereby appropriately adjusted.

The invention enables the reach and rake of the steering column to be separately and independently adjusted using a single motor 15.

Claims

CLAIMS:

1. An adjustable steering column for a vehicle comprising a first section displaceable for adjustment of rake, a second section displaceable for adjustment of reach, a motor, first and second clutches operatively connected to the motor, the first clutch having a driven member for displacing the first section and the second clutch having a driven member for displacing the second section, whereby at any instant either the first clutch or the second clutch may be engaged to enable the required adjustment to be made.

2. An adjustable steering column according to claim 1 in which the first section of the steering column is a pivotal section of the steering column and operation of the first clutch pivots the first section to enable the rake to be adjusted.

3. An adjustable steering column according to claim 1 or 2 in which the driven member associated with the first clutch drives the first section through gearing.

4. An adjustable steering column according to claim 3 when appendant to claim 2 in which the gearing comprises a worm gear drivable by the first clutch and a meshing gear drivably connected to the pivotable first section of the steering column.

5. An adjustable steering column according to any preceding claim in which the second section of the steering column is a telescopable section of the steering column and operation of the second clutch effects telescoping movement thereof to enable the reach to be adjusted.

6. An adjustable steering column according to any preceding claim in which the driven member associated with the second clutch drives the second section through a screw-threaded member.

7. An adjustable steering column according to claim 6 when appendant to claim 5 in which the screw-threaded member co-operates with a member attached to a fixed part of the steering column, the screw threaded member and the second clutch being carried by the second section so that operation of the second clutch causes a telescoping movement of the second section via the screw thread.

8. An adjustable steering column according to any preceding claim in which the first and second clutches are coaxial.

9. An adjustable steering column according to any preceding claim in which the first clutch is a cone clutch.

10. An adjustable steering column according to any preceding claim in which the second clutch is a cone clutch.

11. An adjustable steering column according to any preceding claim in which the two clutches are connected to opposite end faces of a drive element drivable by the motor.

12. An adjustable steering column according to claim 11 in which the drive element is driven by the motor via a transmission.

13. An adjustable steering column according to any preceding claim in which the drive element is movable so as to engage either the first or second clutch.

14. An adjustable steering column for a vehicle constructed and arranged substantially as described herein with reference to the accompanying drawing.