Steering Column Friction Plate Width Movement Restriction

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Solution Overview

Problem

Conventional steering column devices face issues with the movement of telescopic friction plates in the width direction due to bending or warping, which affects the stability of the steering wheel's adjusted position, as the cam device's unlocking mechanism does not adequately restrict the movement of these plates.

Innovation Solution

The steering column device incorporates a hook portion with a cantilever beam structure and a restricting projection that limits the movement of the friction plate in the width direction, ensuring the plate remains stable and securely engaged, even when the cam device is unclamped.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the cam device is unlocked to allow adjustment of the steering wheel position, then the adjustability and ease of operation are improved, but the friction plate may move excessively in the width direction due to bending or warping, worsening the stability and reliability of the adjusted position

Engineering Contradiction:

Improveadjustability of steering wheel positionVSAvoidstability of adjusted position

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The friction plate is designed with different functional zones: a first region that contacts the adjusting rod for frictional engagement, and a second region with a curved outer side surface that provides structural stability. This local differentiation allows the plate to maintain its position reliably while still allowing adjustment when unlocked.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The outer side surface of the friction plate features an asymmetric curved shape rather than a symmetric flat surface. This asymmetric curvature is specifically designed to prevent excessive movement in the width direction while maintaining the necessary friction engagement with the adjusting rod, thus improving reliability without sacrificing adjustability.

Inventive Principle:

Principle #4Asymmetry

2Reliability

If the friction plate is made more rigid to prevent bending and warping, then the stability and reliability are improved, but the ability to accommodate adjustment movements and maintain friction engagement may be reduced, worsening the ease of operation

Engineering Contradiction:

Improvestability of adjusted positionVSAvoidadjustability of steering wheel position

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The friction plate incorporates a curved outer side surface that can dynamically accommodate small deformations and movements during adjustment. This dynamic geometry allows the plate to maintain contact with the adjusting rod while preventing excessive movement, thus preserving both adjustability and stability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The curvature parameter of the outer side surface is specifically optimized to balance rigidity and flexibility. The curved shape provides sufficient structural stability to prevent warping while maintaining the geometric characteristics needed for friction engagement during adjustment movements.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If the hook portion structure is simplified to reduce device complexity, then the ease of manufacture is improved, but the ability to restrict movement of the friction plate may be insufficient, worsening the reliability

Engineering Contradiction:

Improvesimplicity of hook portion structureVSAvoidrestriction of friction plate movement

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The movement restriction function is extracted and concentrated in the curved outer side surface region of the friction plate itself, rather than requiring a complex hook portion structure. This extraction allows for a simpler overall design while maintaining reliable movement restriction through the geometric characteristics of the curved surface.

Inventive Principle:

Principle #2Taking out (Extraction)

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 configuration effectively restricts the movement of the friction plate, maintaining the steering wheel's adjusted position and preventing the hook margin from becoming too small, thereby enhancing the stability and reliability of the steering column device.

Implementation Method 1

a friction plate having a long hole extending in a direction in which a position of a steering wheel should be adjustable and through which the adjusting rod is inserted

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

The steering column device incorporates a hook portion with a cantilever beam structure and a restricting projection that limits the movement of the friction plate in the width direction

Methodology Applied

Scientific EffectCantilever beam structure:

Data Source

PatentUS11970205B2Steering column device

Publication Date: 2024.04.30 NSK LTD

AI summary

A steering column device includes a friction plate having a long hole though which an adjusting rod is inserted and a mounting hole, and sandwiched at least one of a portion between one of inner-side surfaces of a pair of support plate portions and an outer-side surface of a column-side bracket of a steering column, and a portion between one of outer-side surfaces of the pair of support plate portions and one of inner-side surfaces of a pair of pressing portions. The steering column device includes a hook portion having a cantilever beam structure that is inserted through the mounting hole in the width direction, and the hook portion has a restricting projection for restricting movement in the width direction of the friction plate.