Passive impact restraining vehicular steering column assembly

• US 5,082,311 A
• Filed: 10/01/1990
• Issued: 01/21/1992
• Est. Priority Date: 10/01/1990
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Motor Company
• Inventors: Melotik, Joseph J.
• Primary Examiner(s): Marmor, Charles A.
• Assistant Examiner(s): FERRITER, KARIN L
• Application Number:
  US07/591,178
• Time in Patent Office: 477 Days
• Field of Search: 280/777, 280/779, 280/780, 188/371, 188/374, 188/375, 188/376, 188/377, 74/492
• US Class Current: 280/777
• CPC Class Codes: B62D 1/195 Yieldable supports for the steering column

Abstract

A passive impact energy absorbing collapsible steering column assembly including a main support bracket fixed at its base to the steering column body and having side members extending in the direction of the steering column and disposed on opposite sides of the steering column. Each side member including a guide slot bifurcating the side member into separate side rail portions, one of which constitutes a guide rail and the other constituting an impact energy absorbing side rail. A bolt is passed through each guide slot to secure the main support bracket to a support structure and is of a diameter greater than the width of the guide slot thereby offering resistance through bending deformation of the energy absorbing side rail portion to the collapse of the steering column body throughout the period of sustained impact. Each side member including a tapered transition portion immediately adjacent the initial frictional clamping position of bolt which allows immediate release of any frictional clamping resistance upon initial collapse of the steering column body relative to the support structure and main support bracket. The bolt further providing an axis upon which the steering column body may be tilted in the event of sustaining impact load having a vertical force vector exceeding a predetermined magnitude.

Claims

1. A vehicle energy absorbing steering column assembly, comprising:

a steering column;

a steering shaft rotatably supported within said steering column and adapted to receive a steering wheel at one end and to engage a steering gear mechanism at its other end;

an energy absorbing main support member affixed to said steering column and adapted to support the steering column from a portion of the vehicle body;

said main support member providing means for (i) allowing said steering column to collapse forwardly along a fixed axial path in the event of an impact of predetermined magnitude upon the steering wheel in the direction of the front of the vehicle, and (ii) absorbing the energy of such impact solely by plastic deformation of said support member;

said main support member providing the sole support means for supporting said steering column beyond the point of any initial axial collapse of said steering column;

said main support member being frictionally clamped to the vehicle dashboard support structure by a fastening means located at two points dispose laterally from one another on opposite sides of said steering column;

said support member being released from frictional clamping engagement relative to the vehicle dashboard support structure substantially instantaneously upon receiving said impact of predetermined magnitude;

said fastening means including a guide portion for guiding said support member along said fixed axial path throughout the axial collapse of said steering column;

said fastening means providing an axis substantially perpendicular to said axial path and about which said support member may be plastically deformed to further absorb said impact;

said main support member comprising a bracket having a base portion and two side portions disposed on opposite ends of said base portion;

said base portion being disposed in a plane substantially perpendicular to the axis of said steering column and constituting a support for said steering column;

said side portions being disposed in a plane substantially perpendicular to said base portion;

each said side portion including a slot defined by oppositely disposed side rails;

said slot being sufficiently wide at the end nearest said base to allow a guide pin to pass therethrough, the remainder of said slot being of a width less than said guide pin;

one said side rail of each side portion being plastically deformable in said plane upon said steering column receiving an impact of predetermined magnitude sufficient to release said support member from the portion of the vehicle body supporting the steering column, whereby the energy of such impact may be absorbed in a controlled mode; and

the other said side rail of each side portion being sufficiently wide to withstand plastic deformation in said plane, thereby providing a guide plane engaging said guide pin and maintaining said steering column in said axis throughout the extent of any collapse of said steering column along said axis.

2. The invention of claim 1, wherein each said side portion includes a transition section at the end thereof nearest said base portion, said transition portion decreasing in thickness beginning about at said base and the forward end of said slot, said forward end constituting the point at which the guide pin passes through said slot to frictionally clamp the support member between the guide pin and the vehicle body, whereby upon the steering column receiving said impact of predetermined magnitude, the frictional engagement holding the support member will be released as said impact causes said steering column assembly to axially collapse a first incremental distance and any further axial collapse of the steering column assembly will result in the impact energy being absorbed substantially exclusively by plastic deformation of the support member side rail portions.

3. The invention of claim 2 wherein each said slot includes a rearward end defining the full limit of axially forward travel of said support member.

4. The invention of claim 3 wherein said transition portion constitutes a minor portion of the total length of each said side rail, and the remainder of each said side rail being of substantially uniform thickness.

5. The invention of claim 4 wherein the width of the one said side rail of each side portion is non-uniform thereby providing a variable energy absorption rate dependent upon the axial extent of the steering column assembly collapse relative to the portion of the vehicle body from which it is supported.

6. The invention of claim 1 wherein said steering shaft comprises an upper portion, an intermediate portion and a lower portion;

said lower portion being adapted to be coupled to the steering gear mechanism;

said upper portion extending from the steering wheel through a forward end of said steering column and being coupled to said intermediate portion; and

said intermediate portion having an inner steering shaft concentrically and telescopically received within an outer steering shaft, said inner steering shaft collapsing within said intermediate portion as said steering column axially collapses relative to the portion of the vehicle body to which it is supported.

7. A vehicle energy absorbing steering column assembly, comprising:

a steering column;

a steering shaft rotatably supported within said steering column and adapted to receive a steering wheel at one end and to engage a steering gear mechanism at its other end;

an energy absorbing main support member affixed to said steering column and adapted to support the steering column from a portion of the vehicle body;

said main support member providing means for (i) allowing said steering column to collapse forwardly along a fixed axial path in the event of an impact of predetermined magnitude upon the steering wheel in the direction of the front of the vehicle, and (ii) absorbing the energy of such impact solely by plastic deformation of said support member;

said main support member providing the sole support means for supporting said steering column beyond the point of any initial axial collapse of said steering column;

said main support member being frictionally clamped to the vehicle dashboard support structure by a fastening means;

said support member being released from frictional clamping engagement relative to the vehicle dashboard support structure as provided by said fastening means substantially instantaneously upon receiving said impact of predetermined magnitude;

said fastening means including a guide portion for guiding said support member along said fixed axial path throughout the axial collapse of said steering column; and

said fastening means providing an axis substantially perpendicular to said axial path and about which said support member may be plastically deformed to further absorb said impact.

8. The invention of claim 7 wherein said fastening means further includes a pair of shear clips laterally disposed on opposite sides of said steering column and fixed to said steering column body and clamp means extending through said shear clips and secured to the portion of the vehicle from which it is supported.

9. The invention of claim 7 wherein said main support member comprises a bracket having a base portion disposed in a plane substantially perpendicular to the axis of said steering column and constituting a support for said steering column;

an adjoining portion being disposed in a plane substantially perpendicular to said base portion;

said adjoining portion including a slot defined by oppositely disposed side rails;

said guide portion of said fastening means including a guide pin;

said slot being sufficiently wide at the end nearest said base portion to allow said guide pin to pass therethrough, the remainder of said slot being of a width less than said guide pin;

at least one said side rail of said adjoining portion being plastically deformable in said plane upon said steering column receiving an impact of predetermined magnitude sufficient to release said support member from the vehicle structure supporting the steering column, whereby the energy of such impact may be absorbed in a controlled mode.

10. In a vehicle steering column assembly, a support member for affixing a steering column in the vehicle structure, said support member comprising a generally U-shaped bracket, having a base portion and two side portions disposed on opposite ends of said base;

said base portion being disposed in a plane substantially perpendicular to the axis of said steering column and constituting a support for said steering column;

said side portions being disposed in a plane substantially perpendicular to said base portion;

each said side portion including a slot defined by oppositely disposed side rails;

said slot being sufficiently wide at the end nearest portion to allow a guide pin to pass therethrough, the remainder of said slot being of a width less than said pin;

one said side rail of each side portion being plastically deformable in said plane upon said steering column receiving an impact of predetermined magnitude sufficient to release said support member from the vehicle structure supporting the steering column, whereby the energy of such impact may be absorbed in a controlled mode; and

the other said side rail of each side portion being sufficiently wide to withstand plastic deformation in said plane, thereby providing a guide plane engaging said guide pin and maintaining said steering column in said axis throughout the extent of any collapse of said steering column along said axis.

11. The invention of claim 10 wherein each said side portion includes a transition section at the end thereof nearest said base portion, said transition portion decreasing in thickness beginning about at said base and the forward end of said slot, said forward end constituting the point at which the guide pin passes through said slot to frictionally clamp the support member between the guide pin and the vehicle structure, whereby upon the steering column receiving said impact of predetermined magnitude, the frictional engagement holding the support member will be released as said impact causes said steering column assembly to axially collapse a first incremental distance and any further axial collapse of the steering column will result in the impact energy being absorbed substantially exclusively by plastic deformation of the support member side rail portions.

12. The invention of claim 11 wherein each said slot includes a rearward end defining the full limit of axially forward travel of said support member.

13. The invention of claim 12 wherein said transition portion constitutes a minor portion of the total length of each said side rail, and the remainder of each said side rail being of substantially uniform thickness.

14. The invention of claim 13 wherein the width of the one said side rail of each side portion is non-uniform thereby providing a variable energy absorption rate dependent upon the axial extent of the steering column assembly collapse relative to the support structure.