Steering Column Adjustment Drive With Parallel-Axis Gear Meshing

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Solution Overview

Problem

Existing steering column adjustment drives face challenges with complex assembly, space inefficiency, and impaired engagement between drive and driven wheels due to tolerances and wear, particularly when adjusting the length of the steering column.

Innovation Solution

The adjustment drive features a displaceable intermediate axis aligned parallel to the drive and spindle axes, allowing for optimal engagement between the drive and driven gears through a sliding guide or rocker arm, with a spring arrangement for resilient support, ensuring smooth running and minimizing wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an intermediate wheel is arranged between drive wheel and driven wheel with parallel axes, then the engagement between drive and driven wheels is improved, but the device complexity increases due to additional components

Engineering Contradiction:
Improveengagement between drive and driven wheelsVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The intermediate wheel is nested within the same housing as the drive and driven wheels, with all three wheels arranged in parallel within a compact configuration. This nesting approach improves engagement reliability while containing the increased component count within a space-efficient arrangement that does not proportionally increase overall device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Manufacturing precision

If the intermediate axis is made displaceable transversely to axial direction, then the gear meshing is optimized, but the device complexity increases due to sliding guide or rocker arm mechanism

Engineering Contradiction:
Improvegear meshing optimizationVSAvoidmechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The intermediate axis is designed with displacability in the transverse direction through a sliding guide or rocker arm mechanism, allowing dynamic adjustment of the intermediate wheel's position. This dynamic capability enables optimization of gear meshing under varying operating conditions while the mechanism itself is designed to be as simple as possible, using straightforward sliding or rocking motions rather than complex actuation systems.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If a spring arrangement is used for resilient support of intermediate axis, then the operation smoothness is improved, but the device complexity increases

Engineering Contradiction:
Improveoperation smoothnessVSAvoidcomponent count
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

A spring arrangement is incorporated to provide resilient support for the intermediate axis, cushioning variations in engagement forces before they can cause operational irregularities. This beforehand cushioning approach smooths operation by preemptively compensating for force variations, while the spring mechanism is designed to be integrated into the existing structure rather than added as a separate complex subsystem.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Area of stationary object

If the drive axle and spindle axis are arranged parallel, then the space efficiency is improved, but the engagement effectiveness may be impaired due to tolerances and wear

Engineering Contradiction:
Improveinstallation spaceVSAvoidengagement effectiveness
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

An intermediate wheel is arranged between the drive wheel and driven wheel, both with axes parallel to the drive axle and spindle axis. This intermediate element acts as a mediator that improves engagement effectiveness through better tooth contact geometry, while the parallel axis arrangement is maintained to preserve space efficiency. The intermediate wheel compensates for tolerance and wear effects that would otherwise impair engagement in a direct drive configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design achieves a compact, efficient, and simplified assembly with improved gear meshing, reducing wear and optimizing the use of installation space, leading to enhanced occupant safety and smoother operation.

Implementation Method 1

The intermediate axis is mounted so as to be displaceable transversely to the axial direction of the drive axle and spindle axis

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3700799B1Steering column for a motor vehicle
Publication Date: 2022.06.29 THYSSENKRUPP AG
  • EP3700799B1 patent drawingFigure 1~2
  • EP3700799B1 patent drawingFigure 3~4
  • EP3700799B1 patent drawingFigure 5~7

AI summary

The invention relates to a steering column (1) for a motor vehicle, comprising a supporting unit (2) that can be applied to a vehicle body and is used to support an adjusting unit (3) in which a steering shaft (32) is mounted such that it can rotate about a longitudinal axis (L), and an adjustment drive (5) which is arranged between the supporting unit (2) and the adjusting unit (3) and can be used to adjust the adjusting unit (3) in relation to the supporting unit (2), the adjustment drive (5) comprising a threaded spindle (52) with a spindle axis (G), which engages in a spindle nut (51), and the spindle nut (51) and the threaded spindle (52) can be rotatably driven in relation to each other by a servomotor (55), the servomotor (55) comprising a motor shaft (56) coupled to a drive wheel (71, 711) that can be rotated about a drive axis (M), said drive wheel being directly or indirectly operatively engaged with a driven wheel (70, 701) that can be rotated about the spindle axis (G) and is connected to the spindle nut (51) or the threaded spindle (52) for rotation therewith. The aim of the invention is to provide a steering column with an electromotive adjustment drive, at least for longitudinal adjustment, which is compact and easy to produce. To this end, the drive axis (M) and the spindle axis (G) are arranged substantially parallel to each other.