Steering System Shock Absorbing Slide Mechanism

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Solution Overview

Problem

Existing steering systems fail to adequately absorb shock loads during secondary collisions due to insufficient vibration rigidity, leading to decreased operability and protection for drivers.

Innovation Solution

A steering system with a shock absorbing mechanism that includes a slide member which frictionally slides relative to both the upper and lower jackets and the support member, featuring a transmitting portion that contacts both the lower jacket and support member at a position closer to the fixed portion, improving vibration rigidity without adding new components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a slide member is interposed between the lower jacket and the support member to generate frictional resistance force during secondary collision, then the shock absorption capability is improved, but the vibration rigidity decreases due to transmission through the low-rigidity support member portion

Engineering Contradiction:
Improveshock absorption capabilityVSAvoidvibration rigidity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The slide member is divided into two distinct functional portions: a sandwiched portion that contacts the support member (for shock absorption) and a transmitting portion that contacts the lower jacket (for vibration transmission). This segmentation allows each portion to be optimized for its specific function, resolving the contradiction between shock absorption and vibration rigidity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The transmitting portion of the slide member acts as an intermediary element that creates a new vibration transmission path through the lower jacket, bypassing the low-rigidity support member portion. This intermediary structure enables vibration to be transmitted through a higher rigidity path while the sandwiched portion continues to provide shock absorption through friction.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If the slide member is positioned to interpose between the lower jacket and the relatively low-rigidity part of the support member to ensure sufficient frictional resistance force, then the shock absorption is improved, but the vibration is transmitted through the low-rigidity path causing upper jacket vibration

Engineering Contradiction:
Improvefrictional resistance forceVSAvoidvibration transmission
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The slide member is segmented into a sandwiched portion for generating frictional resistance force against the support member and a transmitting portion for transmitting vibration to the lower jacket. This segmentation allows the force-generating function and vibration-transmission function to be spatially separated, enabling optimization of both functions simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the slide member are assigned different functions: the sandwiched portion is positioned to contact the support member for shock absorption, while the transmitting portion is positioned to contact the lower jacket for vibration transmission. This local differentiation of quality allows each region to perform its specific function effectively.

Inventive Principle:
Principle #3Local quality

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 system effectively absorbs shock loads and improves vibration rigidity, ensuring better protection and operability during secondary collisions by transmitting vibrations through a higher rigidity path, while maintaining a simple structure.

Implementation Method 1

the shock absorbing mechanism includes a slide member configured to move together with the upper jacket, and to frictionally slide relative to the lower jacket and the support member upon the secondary collision

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The transmitting portion is formed integrally with the sandwiched portion, and is brought into contact with both of the lower jacket and the support member at a position closer to the fixed portion than the sandwiched portion

Methodology Applied
Scientific EffectVibration transmission: Vibration

Data Source

PatentEP3360756B1Steering system
Publication Date: 2019.12.18 JTEKT CORP
  • EP3360756B1 patent drawingFigure 1
  • EP3360756B1 patent drawingFigure 2
  • EP3360756B1 patent drawingFigure 3~4

AI summary

Provided is a steering system that is configured to absorb a shock load of a secondary collision by a frictional slide between a slide member configured to move together with an upper jacket and each of a lower jacket and a support member, and is high in vibration rigidity with a simple structure. A lower jacket (8) is externally fitted to an upper jacket (7) in a slidable manner. A support member (17) that supports the lower jacket (8) includes a fixed portion (24) that is fixed to a vehicle body (13). A shock of a secondary collision is absorbed by a shock absorbing mechanism (SA). The shock absorbing mechanism (SA) includes second slide members (50) configured to move together with the upper jacket (7), and to frictionally slide relative to the support member (17) upon a secondary collision. The second slide member (50) includes a sandwiched portion (53) that is sandwiched between the support member (17) and the lower jacket (8), and a transmitting portion (54) that is brought into contact with both of the lower jacket (8) and the support member (17) at a position closer to the fixed portion (24) than the sandwiched portion (53).