Steering Device Axial Movement Guide
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Solution Overview
Problem
Conventional steering devices face limitations in impact absorption capacity during secondary collisions, particularly when the collision load direction intersects the axial direction of the inner column, leading to restricted movement due to friction between the inner and outer columns.
Innovation Solution
The steering device incorporates a guide portion with a support face and a regulation face, where the distance from the axis to the regulation face is longer than to the support face, allowing smooth axial movement of the inner member relative to the outer member, and includes a slit mechanism for adjusting the sliding resistance to optimize impact absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner column is allowed to move freely in the axial direction to improve impact absorption, then the impact absorption capacity is improved, but the inner column rotates and presses against the outer column causing friction that prevents movement
Solution Approach 1:
A guide portion with a guide surface is introduced as an intermediary between the inner column and outer column. The guide surface extends in the axial direction and contacts the outer circumferential surface of the inner column, guiding its movement while preventing rotation. This mediator allows the inner column to move axially for impact absorption without rotating and pressing against the outer column, thus resolving the contradiction between movement freedom and movement smoothness.
2Ease of operation
If the contact area between inner column and outer column is increased to reduce friction, then movement smoothness is improved, but the device volume and weight increase
Solution Approach 1:
Instead of increasing the overall contact area between inner and outer columns, the guide surface is designed with specific local characteristics - it extends in the axial direction and is positioned to contact only the outer circumferential surface of the inner column. This localized guide surface provides sufficient guidance and friction reduction without requiring a large contact area, thus avoiding increased device volume and weight while maintaining movement smoothness.
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 enhances the impact absorption capacity by ensuring desired axial movement during secondary collisions, reducing twisting and excessive sliding resistance, and allows for adaptable collision load absorption without significant design changes, thereby improving safety and reducing the device's volume and weight.
Implementation Method 1
the inner member moves in the axial direction relative to the outer member while sliding on the support face
Implementation Method 2
the inner member contacts the regulation face when the inner member is inclined in the radial direction due to a collision load so that an inclination of the inner member in the radial direction is regulated
Data Source
AI summary
A steering device includes an inner column and an outer column which has a guide cylinder portion supporting the inner column to be movable in an axial direction and a holding cylinder portion located at a rear side in the axial direction in relation to the guide cylinder portion and having a slit extending in the axial direction. The guide cylinder portion has a support face which slidably supports an outer circumferential face of the inner column and a regulation face which is located at a front side in the axial direction in relation to the support face and regulates a movement of the inner column in a radial direction. The guide cylinder portion is formed so that a distance from an axis to the regulation face in the radial direction is longer than a distance from the axis to the support face.