Steering Column Leadscrew Sections for Rigidity and Fast Adjustment

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Solution Overview

Problem

Existing adjustment drives for steering columns face a conflict between achieving high rigidity for ergonomic steering and high adjustment speed for stowing, as high rigidity leads to high screwing resistance and energy consumption, while low rigidity results in slow adjustment.

Innovation Solution

The adjustment drive features a threaded spindle with distinct actuator and transition sections, where the actuator section has high screwing torque for rigidity and low thread play for ease of adjustment, and the transition section has reduced screwing torque for faster adjustment, allowing independent optimization of these sections without additional switching elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high screwing torque is used in the actuator section, then rigidity and precision are improved, but energy consumption increases

Engineering Contradiction:
ImproverigidityVSAvoidenergy consumption
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The threaded spindle is divided into two distinct sections: an actuator section with high screwing torque for rigidity and precision during manual steering, and a transition section with reduced screwing torque for energy-efficient adjustment movements. This segmentation allows each section to be optimized for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the threaded spindle are given different local qualities - the actuator section has high screwing torque characteristics for precision and rigidity, while the transition section has reduced screwing torque for energy efficiency. This local differentiation resolves the contradiction by applying the appropriate torque characteristic only where needed.

Inventive Principle:
Principle #3Local quality

2Speed

If high screwing torque is used for rigidity, then adjustment speed decreases, but if low screwing torque is used, then rigidity is reduced

Engineering Contradiction:
Improveadjustment speedVSAvoidrigidity
Core Design Contradiction:
SpeedVSStrength

Solution Approach 1:

The threaded spindle is segmented into an actuator section for precision positioning and a transition section for rapid movement. The transition section's reduced screwing torque enables faster adjustment speeds during stowing operations, while the actuator section maintains high rigidity for ergonomic steering performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between two operational modes depending on the position of the spindle nut: high-torque mode in the actuator section for precision and rigidity, and low-torque mode in the transition section for speed. This dynamic adaptation allows the system to optimize performance for the current operational requirement.

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 design enables efficient adjustment over the entire range with high rigidity in the operating area and high speed in the transition area, reducing energy consumption and maintaining precise, low-vibration operation.

Implementation Method 1

a threaded spindle (52) which engages with an external thread in a spindle nut (51), and a drive unit (55) which is coupled to the threaded spindle (52) or the spindle nut (51) in such a way that the threaded spindle (52) and the spindle nut (51) can be driven in rotation relative to one another

Methodology Applied
Scientific EffectScrew: Screw

Data Source

PatentEP4107049B1Adjustment drive for a steering column, and steering column for a motor vehicle
Publication Date: 2024.01.10 THYSSENKRUPP PRESTA AG
  • EP4107049B1 patent drawingFigure 1~2
  • EP4107049B1 patent drawingFigure 3~4
  • EP4107049B1 patent drawingFigure 5~6

AI summary

The present invention relates to an adjustment drive (5, 6) for a steering column (1) for a motor vehicle, comprising a leadscrew (52, 62), which engages by means of an external screw thread into a leadscrew nut (51, 61), and a drive unit (55, 65), which is coupled to the leadscrew (52, 62) or to the leadscrew nut (51, 61) in such a way that the leadscrew (52, 62) and the leadscrew nut (51, 61) can be driven rotationally relative to one another by overcoming a screw resistance. In order to permit an optimized adjustment over the entire adjustment range, the invention proposes that the leadscrew (52, 62) has at least one actuator section (A, C) and at least one transition section (B), wherein the transition section (B) is designed in such a way that the screw resistance of the leadscrew nut (51, 61) is lower in the transition section (B) than in the actuator section (A, C).