Steering Column Adjustability via Independent Support Force

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Solution Overview

Problem

Existing steering column adjustment mechanisms suffer from stick-slip and rattling noises due to uneven sliding behavior between clamping and sliding surfaces, leading to suboptimal adjustability and noise generation during steering wheel position adjustments.

Innovation Solution

A support device generates a supporting force that is greater than or equal to the weight force of the actuating unit, ensuring the jacket pipe is held in position when the clamping device is released, and adjusts frictional forces independently of the clamping force by pressing the sliding surface against the casing tube with a defined contact pressure, reducing tilting and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the clamping device is released to allow adjustment of the actuating unit, then the adjustability is improved, but the jacket pipe tilts and generates rattling noises due to play between the outside of the tube and the clamping surface

Engineering Contradiction:
ImproveadjustabilityVSAvoidrattling noises
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The support unit is segmented into two distinct functional surfaces: a clamping surface for securing the jacket pipe during normal operation, and a separate sliding surface for supporting the jacket pipe during adjustment. This segmentation allows each surface to be optimized for its specific function, preventing the jacket pipe from tilting and rattling during adjustment while maintaining secure clamping during operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sliding surface acts as an intermediary element between the clamping surface and the jacket pipe during adjustment. When the clamping device is released, the sliding surface provides continuous support to the jacket pipe, preventing it from tilting or generating rattling noises. This intermediary surface enables smooth adjustment motion while maintaining positional stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If sliding surfaces are designed to bear against the outside of the steering column tube with minimal play, then tilting is reduced and operating feel is improved, but stick-slip effects occur between the sliding surfaces and the tube

Engineering Contradiction:
Improveoperating feelVSAvoidstick-slip effects
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The support force pressing the sliding surface against the jacket pipe can be adjusted independently of the clamping force. By optimizing this support force parameter, the system achieves minimal play to prevent tilting while avoiding excessive friction that would cause stick-slip effects. The sliding surface may also be designed with specific geometric parameters (such as curvature or surface finish) to reduce friction and eliminate stick-slip phenomena.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the support force is increased to hold the jacket pipe firmly on the sliding surface, then tilting and noise are reduced, but the frictional forces increase and may impede smooth sliding

Engineering Contradiction:
Improveposition stabilityVSAvoidfrictional forces
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The support force is optimized to a specific range that provides sufficient holding capability to prevent tilting and noise during adjustment, while remaining low enough to allow smooth sliding motion. This parameter optimization balances position stability with ease of adjustment, ensuring the jacket pipe remains stable during motion without creating excessive friction.

Inventive Principle:
Principle #35Parameter changes

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 enhances adjustability and reduces noise by maintaining the jacket pipe's position and controlling frictional forces, resulting in smooth and even sliding behavior during steering column adjustments.

Implementation Method 1

a support device (5) which presses the sliding surface (51) against the outer tube (21) with a support force (S) that can be predetermined independently of the clamping force

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the clamping device (4), which, in the fixing position, clamps the clamping surface (35) against the outer tube (21) with a clamping force (K) to fix the actuating unit (2) relative to the support unit (6)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3408159B1Steering column for a motor vehicle
Publication Date: 2021.03.03 THYSSENKRUPP PRESTA AG
  • EP3408159B1 patent drawingFigure 1~2
  • EP3408159B1 patent drawingFigure 3~5
  • EP3408159B1 patent drawingFigure 6

AI summary

The invention relates to a steering column (1) for a motor vehicle, comprising an adjusting unit (2) with a steering spindle (22) mounted in a casing pipe (21) in a rotatable manner about the longitudinal axis (23) of the steering spindle, a support unit (3) which can be connected to the body of the motor vehicle, in which the casing pipe (21) can be received, and which has at least one clamping surface (35) facing the casing pipe (21), and a clamping device (4) which clamps the clamping surface (35) against the casing pipe (21) with a clamping force (K) in a fixing position in order to fix the adjusting unit (2) relative to the support unit (3) at least in the longitudinal direction and which releases the clamping surface (35) from the casing pipe (21) in a release position and releases an adjustment of the adjusting unit (2) relative to the support unit (3) at least in the longitudinal direction. The support unit (3) has at least one sliding surface (51) which faces the casing pipe (21) and along which the casing pipe (21) can be moved in the longitudinal direction in the release position. The aim of the invention is to provide a steering column (1) with an improved adjustability. According to the invention, this is achieved in that the sliding surface (51) is arranged on a support device (5) which presses the sliding surface (51) against the casing pipe (21) with a supporting force (S) which can be specified independently of the clamping force (K).