Steering Column Spindle Thread Zoning for Stiffness and Speed

Solution Overview

Problem

Existing steering column adjusting drives face a conflict between achieving high stiffness for ergonomic positioning and high adjusting speed for rapid stowage/deployment, as high screw resistance leads to heavy, bulky, and energy-intensive systems with limited adjustability in the transition region.

Innovation Solution

The adjusting drive features a threaded spindle with distinct actuator and transition portions, where the actuator portion has high screw resistance for stiffness and low clearance, and the transition portion has reduced screw resistance for increased adjustability, allowing for optimized adjustment across the entire adjusting region without additional switching elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high screw resistance is used in the threaded spindle to achieve high stiffness for ergonomic positioning, then positioning accuracy is improved, but adjusting speed decreases and power consumption increases

Engineering Contradiction:

Improvepositioning accuracyVSAvoidadjusting speed

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The threaded spindle is divided into multiple threaded sections along its axial direction, each with different screw resistances. The first threaded section has a first screw resistance optimized for positioning accuracy, while the second threaded section has a second screw resistance optimized for adjusting speed. This segmentation allows the system to achieve both high positioning accuracy and high adjusting speed by using different thread characteristics in different regions.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If high screw resistance is used in the threaded spindle to achieve high stiffness, then positioning accuracy is improved, but the drive unit becomes heavier and more energy-intensive

Engineering Contradiction:

Improvepositioning accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The threaded spindle is divided into multiple threaded sections along its axial direction, each with different screw resistances. The first threaded section has a first screw resistance optimized for positioning accuracy, while the second threaded section has a second screw resistance optimized for adjusting speed. This segmentation allows the system to achieve both high positioning accuracy and high adjusting speed by using different thread characteristics in different regions.

Inventive Principle:

Principle #1Segmentation

3Stability of the object's composition

If high screw resistance is used throughout the threaded spindle, then stiffness is improved, but adjustability in the transition region is limited

Engineering Contradiction:

ImprovestiffnessVSAvoidadjustability in transition region

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The threaded spindle is divided into multiple threaded sections along its axial direction, each with different screw resistances. The first threaded section has a first screw resistance optimized for positioning accuracy, while the second threaded section has a second screw resistance optimized for adjusting speed. This segmentation allows the system to achieve both high positioning accuracy and high adjusting speed by using different thread characteristics in different regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the threaded spindle are given different local properties. The first threaded section has high screw resistance for stiffness and positioning accuracy, while the second threaded section has lower screw resistance for fast adjustment in the transition region. Each section is optimized for its specific function, allowing the overall system to achieve both stiffness and adaptability.

Inventive Principle:

Principle #3Local quality

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 a higher linear adjusting speed with the same drive power or lower power consumption, resolving the conflict between stiffness and speed requirements, and allows for easier adaptation to different steering column designs with minimal effort.

Implementation Method 1

a threaded spindle (52) which engages with an external thread in a spindle nut (51)

Methodology Applied

Scientific EffectScrew: Screw

Data Source

PatentUS12091076B2Adjustment drive for a steering column, and steering column for a motor vehicle

Publication Date: 2024.09.17 THYSSENKRUPP PRESTA AG

AI summary

An adjusting drive for a steering column for a motor vehicle may include a threaded spindle with an external thread that engages in a spindle nut and a drive unit that is coupled to the threaded spindle or the spindle nut such that the threaded spindle and the spindle nut are able to be rotatably driven relative to one another by overcoming a screw resistance. To permit an optimized adjustment over the entire adjusting region, the threaded spindle includes at least one actuator portion and at least one transition portion. The transition portion is configured such that the screw resistance of the spindle nut is lower in the transition portion than in the actuator portion.