Steering Column Telescopic Restriction Impact Absorption
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Solution Overview
Problem
Conventional steering column devices detach the inner jacket from the outer jacket after absorbing impact energy, rendering steering operation impossible.
Innovation Solution
A steering column device with a telescopic-position restricting structure, including a restricting protrusion that engages with rear-end and front-end restricting walls, preventing detachment and allowing steering operation by absorbing impact energy through friction within the contraction rail part, eliminating the need for additional structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If shear pins are used to allow inner jacket movement for impact energy absorption, then impact energy absorption is improved, but steering operation becomes impossible after impact due to inner jacket detachment
Solution Approach 1:
The restricting protrusion is divided into two functional parts: a base portion that engages with the rear-end restricting wall to prevent detachment, and a stopper portion that fractures to enable impact energy absorption. This segmentation allows the structure to perform both functions separately.
Solution Approach 2:
The restricting protrusion is pre-configured with a fragile shear part that will fracture under impact load. The base portion is pre-positioned to engage with the rear-end restricting wall, establishing the prevention function before impact occurs.
2Reliability
If additional structures are added to prevent inner jacket detachment, then steering operation capability is improved, but device complexity increases
Solution Approach 1:
The restricting protrusion serves multiple functions: it prevents detachment through engagement with the rear-end restricting wall, absorbs impact energy through stopper fracture, and restricts telescopic position through engagement with front-end and rear-end restricting walls. This multi-functionality eliminates the need for separate structures.
Solution Approach 2:
The detachment prevention function and impact energy absorption function are merged into a single restricting protrusion structure, rather than using separate components for each function.
3Loss of energy
If inner jacket is allowed to move freely for impact absorption, then impact energy absorption is improved, but inner jacket rotates relative to outer jacket preventing steering operation
Solution Approach 1:
The restricting protrusion is segmented into a base portion for rotational constraint and a stopper portion for impact absorption, allowing simultaneous prevention of rotation and energy dissipation.
Solution Approach 2:
The base portion is pre-configured to engage with the rear-end restricting wall, establishing rotational constraint before impact occurs, while the stopper portion is pre-configured to fracture under impact load.
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
Ensures the inner jacket remains engaged with the outer jacket, enabling continuous steering functionality after impact energy absorption by utilizing the friction within the contraction rail part to absorb energy without additional components.
Implementation Method 1
the stopper comes into contact with the front-end restricting wall, fractures from the shear part, and is detached from the restricting protrusion
Implementation Method 2
upon application of a load of a set value or greater to the inner jacket in the axial direction, the restricting protrusion moves inside the telescopic rail part forward in the axial direction together with the inner jacket and the stopper comes into contact with the front-end restricting wall
Implementation Method 3
absorbing the impact energy through friction within the contraction rail part
Data Source
Figure 1
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Figure 3
AI summary
A steering column device (1) has a telescopic-position restricting structure (6). In adjustment of a telescopic position, a restricting protrusion (41) moves inside a telescopic rail part (33) between a front-end restricting wall (36) and a rear-end restricting wall (35). Upon application of a load of a set value or greater to an inner jacket (4) in its axial direction, the restricting protrusion (41) moves inside the telescopic rail part (33) forward in the axial direction together with the inner jacket (4) and a stopper (41b) comes into contact with the front-end restricting wall (36), fractures from a shear part (41c), and is detached from the restricting protrusion (41), thereby allowing the restricting protrusion (41) to move inside the contraction rail part (32) forward in the axial direction.