Steering Column Retaining Ring for Defined Breakaway Force

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Solution Overview

Problem

Existing steering column designs face challenges in reliably adjusting the breakaway force of the sliding capsule, which is often dependent on the tightening torque of screws, making it difficult to specify a defined breakaway force during assembly.

Innovation Solution

A steering column design that uses a retaining ring pressed onto a cylindrical section of the sliding capsule to provide a predetermined clamping force, allowing for independent adjustment of the breakaway force without relying on screw tightening torque, with a washer or spring element optionally used to enhance friction behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a screw fastening is used to fix the sliding capsule to the chassis, then the assembly process is simple, but the breakaway force cannot be reliably adjusted and depends on the tightening torque

Engineering Contradiction:
Improvebreakaway force definitionVSAvoidassembly process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the breakaway force adjustment function from the screw fastening system and relocates it to the retaining ring mechanism. The retaining ring is pressed onto the cylindrical section with a predetermined pressing force that directly determines the breakaway force, separating this critical function from the assembly process and making it reliably adjustable independent of screw tightening torque.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the parameter control mechanism from torque-dependent (screw tightening) to force-dependent (retaining ring pressing force). By controlling the pressing force applied to the retaining ring during assembly, a predetermined breakaway force is established, making the parameter adjustment reliable and independent of subsequent assembly variations.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the retaining ring is pressed onto the cylindrical section with a predetermined pressing force, then the breakaway force is reliably defined and independent of assembly process, but the device structure becomes more complex

Engineering Contradiction:
Improvebreakaway force consistencyVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention segments the sliding capsule into distinct functional portions: a cylindrical section for retaining ring engagement and a collar section for chassis connection. This segmentation allows the breakaway force mechanism (retaining ring on cylindrical section) to be independently controlled from the assembly fastening (screw on collar section), achieving reliable breakaway force definition with minimal structural complexity.

Inventive Principle:
Principle #1Segmentation

3Strength

If the sliding capsule is firmly fixed to the chassis with high tightening torque, then the connection strength is improved, but the breakaway force becomes unpredictable and dependent on assembly variations

Engineering Contradiction:
Improveconnection strengthVSAvoidbreakaway force precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The invention introduces the retaining ring as an intermediary element between the sliding capsule and the breakaway force requirement. The retaining ring, pressed onto the cylindrical section with controlled pressing force, mediates the breakaway force independently of the screw connection strength. This allows the screw to provide strong connection without influencing the precision of the breakaway force, which is controlled solely by the retaining ring pressing force.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The breakaway force is reliably defined and independent of the assembly process, ensuring consistent performance regardless of screw tightening torque, and the design decouples the breakaway force from the assembly situation, preventing unintentional jamming or increased contact pressure.

Implementation Method 1

a retaining ring (4) pressed onto the cylindrical section (30) with a predetermined pressing force, by means of which the assembly support (2) is held on the sliding capsule (3)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The mounting bracket, together with the additional components of the steering column accommodated thereon, is displaced along the open elongated holes in relation to the slide capsules which are firmly fixed to the chassis of the motor vehicle

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3122612B1Steering column for a motor vehicle
Publication Date: 2018.02.28 THYSSENKRUPP AG
  • EP3122612B1 patent drawingFigure 1~8
  • EP3122612B1 patent drawingFigure 4~7

AI summary

A steering column for a motor vehicle may include a mounting support with at least one open elongated hole and at least one sliding capsule arranged in the open elongated hole. The sliding capsule may be secured on a chassis of a motor vehicle and may retain the mounting support. The mounting support in a crash event can move relative to the sliding capsule secured on the chassis of the motor vehicle. The sliding capsule may include a cylindrical section that extends through the open elongated hole. The mounting support may be retained on the sliding capsule by a retaining ring pressed onto the cylindrical section.