Adjustable Steering Columns

• US 20170203780A1
• Filed: 07/22/2015
• Published: 07/20/2017
• Est. Priority Date: 07/22/2014
• Status: Active Grant

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Davies, Niclas, Appleyard, Michael
• Granted Patent: US 10,442,456 B2
• Time in Patent Office: Days
• CPC Class Codes: B62D 1/184 Mechanisms for locking columns at selected positions
• CPC Class Codes: B62D 1/185 adjustable by axial displacement, e.g. telescopically B62D1/183, B62D1/187, B62D1/19 take precedence
• CPC Class Codes: B62D 1/195 Yieldable supports for the steering column

Abstract

An adjustable steering column assembly which includes an adjustable shroud that supports a steering column shaft, a support bracket that is fixed in position in the vehicle, and a clamp mechanism that selectively secures the shroud to the support bracket, the clamp mechanism comprising a fixed rack that is secured to the shroud or the bracket, and a moving rack that is movable towards and away from the fixed rack during operation of the clamp mechanism, in which the fixed rack comprises a support portion and at least one row of teeth which are carried by the support portion arranged spaced apart from one another, and the moving rack comprises a support portion and at least one row of teeth which are carried by the support portion. One or both of the support portion and teeth of the fixed rack are resiliently flexible so that in the event of moving from the first to the second position where a tooth-on-tooth situation arises the teeth of the moving block displace the teeth of the fixed block in the direction of movement of the moving rack so that the teeth of the moving rack can occupy the region that would otherwise be occupied by the teeth of the fixed rack teeth.

Claims

1. An adjustable steering column assembly which includes an adjustable shroud that supports a steering column shaft, a support bracket that is fixed in position in the vehicle, and a clamp mechanism that selectively secures the shroud to the support bracket, the clamp mechanism comprising a fixed rack that is secured to the shroud or the bracket, and a moving rack that is movable towards and away from the fixed rack during operation of the clamp mechanism, in which in a first unclamped position the teeth of the moving rack are spaced apart from the teeth of the fixed rack, and on moving to a second clamped position the teeth of the moving rack are moved towards the fixed rack so that in a normal non tooth-on-tooth condition the teeth of the fixed rack engage the teeth of the moving rack, thereby to selectively permit an amount of relative movement between the shroud and bracket that is required during reach and/or rake adjustment of the steering column assembly, in which:

the fixed rack comprises a support portion and at least one row of teeth which are carried by the support portion arranged spaced apart from one another,

the moving rack comprises a support portion and at least one row of teeth which are carried by the support portion;

and characterised in that one or both of the support portion and teeth of the fixed rack are resiliently flexible so that in the event of moving from the first to the second position where a tooth-on-tooth situation arises the teeth of the moving block displace the teeth of the fixed block in the direction of movement of the moving rack so that the teeth of the moving rack can occupy the region that would otherwise be occupied by the teeth of the fixed rack teeth, the teeth of the fixed rack being retained in that position until subsequent displacement of the shroud relative to the bracket at which time the teeth of the fixed rack clear the teeth of the moving rack and move into engagement with the teeth of the moving rack.

2. An adjustable steering column assembly according to claim 1 in which the fixed rack is supported on a base plate which is fixed to the shroud or bracket and the fixed rack comprises a support portion that engages the base plate and an engaging part that carries the rack of teeth.

3. An adjustable steering column assembly according to claim 2 in which the base plate includes a locating feature that securely locates a part of the fixed rack relative to the base plate.

4. An adjustable steering column assembly according to any preceding claim in which the fixed rack comprises a support portion that is connected to at least one row of teeth through one or more flexible arms, the flexibility of the fixed rack being primarily provided by the flexibility of the arm or each of the arms.

5. An adjustable steering column assembly according to claim 4 in which each arm functions as a leaf spring, storing energy as it flexes which will subsequently be released to cause the fixed and moving racks to interengage as the shroud moves away from the tooth-on-tooth condition, for instance in the event of a crash.

6. An adjustable steering column assembly according to any preceding claim when dependent from claim 2, in which the support portion, engaging portion and teeth of the fixed rack are formed from a single component with the teeth at rest being spaced apart from the backing part and able to deflect resiliently towards the backing part.

7. An adjustable steering column assembly according to any preceding claim when dependent from claim 2, in which the base plate has a generally flat surface, and the fixed rack supports the teeth of the fixed rack in a position spaced apart from the base plate when the clamp mechanism is in the first position.

8. An adjustable steering column assembly according to any preceding claim when dependent from claim 2, in which the base plate is non-planar, for example bowed, to provide a spacing between the base plate and the teeth of the fixed rack.

9. An adjustable steering column assembly according to any preceding claim in which the fixed rack and the moving rack each comprise two elongate rows of teeth that are spaced apart, preferably running parallel to one another, in which an elongate slot is provided between the two rows, and the clamp mechanism includes a clamp pin that passes through the slot.

10. An adjustable steering column assembly according to claim 9 in which the moving rack is free to move longitudinally relative to the axis of the clamp pin.

11. An adjustable steering column assembly according to claim 9 or 10 in which the two rows of teeth of the fixed rack are interconnected by two flexible arms, one at each end of the rows, the slot where provided being located between the rows and the arms.

12. An adjustable steering column assembly according to claim 11 in which the arms are bowed with a central portion midway between the rows being fixed to the base plate of the support bracket or shroud so that the teeth are held spaced apart from the base plate.

13. An adjustable steering column assembly substantially as described herein with reference to and as illustrated in the accompanying drawings.