Steering Column Release Load Adjustment via Low-Friction Coating

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Solution Overview

Problem

Existing steering column devices face challenges in adjusting the release load precisely and maintaining stability during secondary collisions, with existing solutions requiring strict dimensional precision and limiting the allowable range of tightening torque, which can lead to unstable fixation and increased risk of damage.

Innovation Solution

A steering column device with a release capsule that includes a sleeve, sliding plate, and lock member, where the sliding plate is coated with a low-friction synthetic resin film, allowing for adjustable release load through the tightening torque of the lock member, decoupling the release load from the tightening torque and reducing frictional forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bush is fitted to a notch groove and sandwiched by a collar and ring to form a capsule, then the vehicle body mounting bracket can be fixed to the vehicle body, but the release load becomes difficult to adjust precisely due to frictional forces and requires strict dimensional precision

Engineering Contradiction:
Improvefixation stabilityVSAvoiddimensional precision of bush
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention changes the physical-chemical parameter of the contact surface by coating the sliding plate with a low-friction synthetic resin film containing solid lubricant. This parameter change (reducing friction coefficient) allows the release load to be reduced and adjusted precisely without requiring strict dimensional precision of the bush, thereby resolving the contradiction between fixation stability and manufacturing precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The sliding plate acts as an intermediary element between the capsule and the vehicle body mounting bracket. By introducing this intermediate component with a low-friction coating, the invention mediates the interaction between the fixing structure and the release mechanism, enabling precise release load adjustment while maintaining reliable fixation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If a washer coated with synthetic resin film of low friction or sliding plate is used to reduce release load, then the release load can be reduced, but the fixing to the vehicle body becomes unstable and requires strict limitation of tightening torque

Engineering Contradiction:
Improverelease loadVSAvoidfixation stability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The invention optimizes the friction parameter by applying a low-friction synthetic resin film coating to the sliding plate. This parameter modification enables the system to achieve both low release load and stable fixation simultaneously, eliminating the need to strictly limit tightening torque while maintaining reliable vehicle body mounting

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the tightening torque of a bolt is strictly limited to maintain stable fixation, then the fixation can be stabilized, but the allowable range of tightening torque is reduced and increases the risk of damage

Engineering Contradiction:
Improvefixation stabilityVSAvoidallowable range of tightening torque
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

By changing the friction parameter through the low-friction coating on the sliding plate, the invention expands the allowable range of tightening torque. The coating reduces frictional interference, allowing broader torque specifications while maintaining stable fixation, thereby increasing adaptability and reducing damage risk

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 configuration allows for a low and consistent release load, preventing variations due to tightening torque changes and enhancing the stability of the vehicle body mounting bracket, thereby reducing the risk of damage during secondary collisions.

Implementation Method 1

the sliding plate is coated with a low-friction synthetic resin film, allowing for adjustable release load through the tightening torque of the lock member

Methodology Applied
Scientific EffectLow-friction synthetic resin film: Lubrication

Data Source

PatentEP3199424B1Steering column device
Publication Date: 2019.07.03 NSK LTD
  • EP3199424B1 patent drawingFigure 1
  • EP3199424B1 patent drawingFigure 2
  • EP3199424B1 patent drawingFigure 3

AI summary

Provided is a steering column device wherein a release load can be easily adjusted, a variation in the release load is small, and the steering column device has a release capsule which enables a vehicle body mounting bracket to be easily mounted to a vehicle body. A slide plate (9) is fixed to a flange (21) using a lock member (8), which engages with a sleeve (7) through threads, such that a release load is adjusted to a desired value in advance. An fixing bolt (10) fastens and fixes the sleeve (7) to a vehicle body (3) when fastening and fixing the flange (21) to the vehicle body (3). A release load at which an upper vehicle body mounting bracket (2) is released from the vehicle body (3) can be adjusted without changing tightening torque of the fixing bolt (10).