Steering Column Movable Lug Axial Adjustment

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Solution Overview

Problem

Existing steering column systems have a slow and inefficient retraction mechanism for the steering wheel, which hinders quick access and egress, especially when the retraction stroke is greater than the adjustment stroke, leading to significant execution time.

Innovation Solution

The steering column design incorporates a movable bracket and axial adjustment gearmotor, combined with a tiltable column and vertical adjustment gearmotor, actuated by a control device, allowing simultaneous operation of these motors to increase retraction speed and flexibility, with features like sliding tubes and guide systems to reduce friction and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the axial adjustment function is used for retraction, then the steering wheel can be retracted, but the retraction speed is slow and execution time is significant

Engineering Contradiction:
Improveretraction speedVSAvoidexecution time
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The system dynamically switches between two operational modes: axial adjustment mode for precise positioning and retraction mode for rapid retraction. The retraction mode engages a dedicated retraction gearmotor that provides high-speed retraction movement, while the axial adjustment gearmotor handles precise positioning. This dynamic mode switching resolves the contradiction by providing both speed (during retraction) and precision (during positioning).

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The steering column system is segmented into two independent adjustment mechanisms: an axial adjustment mechanism with its own gearmotor for precise depth control, and a retraction mechanism with a dedicated retraction gearmotor for rapid retraction. This segmentation allows each mechanism to be optimized for its specific function, with the retraction gearmotor providing high-speed operation without compromising the precision of the axial adjustment mechanism.

Inventive Principle:
Principle #1Segmentation

2Length of moving object

If the retraction stroke is greater than the adjustment stroke, then more space is freed for driver access, but the execution time increases significantly

Engineering Contradiction:
Improveretraction strokeVSAvoidexecution time
Core Design Contradiction:
Length of moving objectVSLoss of time

Solution Approach 1:

The system changes the speed parameter during retraction by engaging the retraction gearmotor, which operates at a higher speed than the axial adjustment gearmotor. This parameter change allows the system to cover longer retraction strokes without proportionally increasing execution time, as the high-speed retraction mechanism compensates for the extended distance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The retraction mechanism enables continuous high-speed retraction movement over the entire retraction stroke length. Unlike the axial adjustment mechanism that operates slowly throughout its range, the retraction gearmotor maintains high speed throughout the retraction stroke, ensuring that even long retraction distances are covered efficiently without interruptions or speed reductions.

Inventive Principle:
Principle #20Continuity of useful action

3Length of moving object

If a movable bracket is added to increase retraction length, then the retraction stroke is extended, but the device complexity increases

Engineering Contradiction:
Improveretraction strokeVSAvoidstructure complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The bracket is designed with multi-functionality: it serves as both a structural support element and a movable component that extends the retraction stroke. The bracket is actuated by the retraction gearmotor to provide additional retraction movement beyond what the outer tube alone could achieve. This universal design allows the bracket to contribute to both structural integrity and extended retraction capability without requiring entirely separate mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The retraction function merges the movement of the bracket with the movement of the outer tube. Both components move axially in coordination under the control of the retraction gearmotor, combining their individual travel distances to achieve the total extended retraction stroke. This merging approach allows the system to achieve longer retraction without proportionally increasing complexity, as the components work together in a coordinated manner.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances the retraction speed and flexibility of the steering wheel, improving access and egress by combining the movements of the bracket, outer tube, and column tilt, reducing execution time and enhancing ergonomic positioning.

Implementation Method 1

the axial adjustment geared motor is connected to the outer tube by a threaded shaft. The threaded axle allows fine adjustment of the steering wheel by the driver.

Methodology Applied
Scientific EffectThreaded shaft mechanism: Screw

Implementation Method 2

the sliding of the outer tube on the inner tube takes place with a sheath. This makes it possible to limit friction forces and noise during the axial adjustment of the steering wheel.

Methodology Applied
Scientific EffectFriction reduction: Friction

Implementation Method 3

the tab slides inside the cap by means of a guide system composed of rails and balls. This gives the same advantages as with the sheath for retracting the steering wheel and this also avoids play between the parts in order to have high stiffness.

Methodology Applied
Scientific EffectBall bearing guidance: Ball Bearing

Data Source

PatentEP2956349B1Device for stowing a steering column
Publication Date: 2018.12.12 ROBERT BOSCH AUTOMOTIVE STEERING VENDOME SAS
  • EP2956349B1 patent drawingFigure 1
  • EP2956349B1 patent drawingFigure 2
  • EP2956349B1 patent drawingFigure 3

AI summary

The steering column (1) according to the invention includes a lug (3), a casing (2), an inner tube (4), an outer tube (5), a steering wheel end-piece (6), and at least one adjustment gear motor, (7, 8) characterized in that the lug (3) is axially movable and in that the column (1) includes a gear motor (9) controlling the lug (3). Having a movable lug (3) makes it possible to increase the stowing length of the steering wheel. Indeed, the range of movement is the sum of the movements of the lug (3) and the adjustment gear motor (7, 8) whereas, in the prior art, only the outer tube (5) is translatably or vertically movable.