Steering Column Spindle Locking for Defined Adjustment Modes

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Solution Overview

Problem

The existing motor-adjustable steering column adjustment drives have limited adjustment paths due to the length of the threaded spindle, leading to undefined operating modes and inconsistent haptic and acoustic feedback, which affects the ergonomic experience and design freedom, especially in luxury vehicles.

Innovation Solution

A locking device is introduced that can be switched between two positions to clearly define the activation of either the first or second spindle drive, ensuring consistent operation and independent transmission ratios, allowing for defined adjustment modes and improved ergonomics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a multi-stage adjustment drive with telescopically nested spindle drives is used to achieve larger adjustment ranges, then the adjustment path is extended, but the operating mode becomes undefined and haptic/acoustic feedback becomes inconsistent

Engineering Contradiction:
Improveadjustment pathVSAvoidoperating mode definition
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The locking device is designed to be switchable between two positions, allowing the system to dynamically transition between different operating modes. In the first position, the external threaded spindle is locked to the spindle nut for the first spindle drive; in the second position, it is locked to the internal threaded spindle for the second spindle drive. This dynamic switching ensures defined operating modes while achieving extended adjustment ranges.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking device acts as an intermediary mechanism that selectively couples the external threaded spindle to either the spindle nut or the internal threaded spindle. This intermediary component ensures that only one spindle drive is active at a time, providing consistent haptic and acoustic feedback while enabling multi-stage adjustment for extended paths.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If both spindle drives have the same transmission properties to enable multi-stage adjustment, then the adjustment mechanism is simplified, but design freedom is limited

Engineering Contradiction:
Improvespindle drive configurationVSAvoiddesign freedom
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The switchable locking device enables the system to operate in different configurations: either with both spindle drives having the same transmission properties for simplified manufacturing, or with different transmission properties for enhanced design freedom. The locking mechanism allows selective engagement of different spindle drives, providing adaptability in transmission ratios while maintaining ease of manufacture through standardized components.

Inventive Principle:
Principle #15Dynamics

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 solution provides a clear and consistent adjustment behavior, enhancing the haptic and acoustic properties and design freedom by ensuring only one spindle drive is active at a time, allowing for tailored adjustment characteristics in different modes.

Implementation Method 1

an external threaded spindle (62) having an external thread (620) into which a spindle nut (63) engages, and having an internal thread (621) into which an internal threaded spindle (61) engages

Methodology Applied
Scientific EffectThreaded engagement: Screw

Data Source

PatentEP4175865B1Steering column for a motor vehicle
Publication Date: 2024.05.01 THYSSENKRUPP PRESTA AG
  • EP4175865B1 patent drawingFigure 1~2
  • EP4175865B1 patent drawingFigure 3~4
  • EP4175865B1 patent drawingFigure 5~6

AI summary

The present invention relates to an adjusting drive (6) for a power-adjustable steering column (1) for a motor vehicle, comprising an externally threaded spindle (62) which has an external thread (620) engaging a spindle nut (63) and which has an internal thread (621) in which an internally threaded spindle engaes, wherein the spindle nut (63), the externally threaded spindle (62) and the internally threaded spindle (61) can be driven in rotation relative to one another about an axis (G) by a motor drive unit (64). In order to improve the adjustment behaviour, in particular with regard to haptics and acoustics, and to increase the freedom of design, the invention proposes that a locking device (7) which is switchable between a first position and a second position is provided. In the first position the externally-threaded spindle (62) is locked in a rotationally fixed manner to the spindle nut (63), and in the second position the externally threaded spindle (62) is locked in a rotationally fixed manner to the internally threaded spindle (61).