Steering Column Impact Absorption for Secondary Collision Loads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing steering column devices with impact absorbing mechanisms do not effectively increase the absorbed amount of impact load applied to the steering wheel during a secondary collision, as described in WO2016/114034.
Innovation Solution
The steering column device incorporates an inner column, outer column, vehicle-body-side bracket, adjusting rod, pressing portions, telescopic friction plate, support bracket, and an impact absorbing member made of wire material with a base portion, folded portion, and extending portion, which are designed to absorb and distribute impact loads by allowing the inner column to displace forward during a secondary collision, thereby increasing the absorbed impact load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shear pin made of synthetic resin is used to join the inner-column bracket to the inner column, then the impact load is absorbed when the shear pin is sheared, but the absorbed amount of impact load is insufficient
Solution Approach 1:
The impact absorbing mechanism is divided into multiple segments: the telescopic friction plate that detaches from the outer column, and the shear pin that joins the inner-column bracket to the inner column. This segmentation allows the impact load to be absorbed in stages, first by the telescopic friction plate detachment and then by the shear pin shearing, thereby increasing the total absorbed amount of impact load.
Solution Approach 2:
The telescopic friction plate is pre-positioned between the inner column and outer column to provide initial cushioning. When impact occurs, the telescopic friction plate detaches first, absorbing part of the impact energy before the shear pin shears. This beforehand cushioning increases the total absorbed amount of impact load.
2Object-affected harmful factors
If the steering wheel position is fixed, then the steering column structure is simple, but the driver's body is subjected to large impact load during secondary collision
Solution Approach 1:
The steering column is designed with dynamic characteristics through the telescopic friction plate that can detach and the shear pin that can shear under impact load. This allows the steering wheel to move forward during secondary collision, converting the static structure into a dynamic one that absorbs impact energy, thereby reducing the impact load on the driver's body.
Solution Approach 2:
The telescopic friction plate acts as an intermediary element between the inner column and outer column. During normal operation, it maintains the steering wheel position. During impact, it serves as a mediator that detaches to allow controlled movement, absorbing impact energy and protecting the driver's body from excessive impact load.
3Reliability
If the telescopic friction plate is firmly fixed to the outer column, then the steering wheel position is stable, but the impact load cannot be effectively absorbed during secondary collision
Solution Approach 1:
The telescopic friction plate is pre-positioned and firmly fixed to the outer column during normal operation to maintain steering wheel position stability. However, the design incorporates a detachment mechanism that activates under impact conditions. This preliminary positioning followed by controlled detachment allows both position stability during normal use and impact load absorption during secondary collision.
Solution Approach 2:
The fixing strength of the telescopic friction plate to the outer column is designed to change under different conditions. During normal operation, the plate is firmly fixed to maintain position stability. During impact, the fixing strength is reduced through the detachment mechanism, allowing the plate to separate and absorb impact energy, thus changing the parameter of fixing strength based on operational conditions.
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 significantly enhances the absorbed impact load on the steering wheel during a secondary collision compared to previous designs, ensuring better protection for the driver by allowing the steering wheel to displace forward and alleviating impact loads effectively.
Implementation Method 1
a telescopic friction plate, and a support bracket... The telescopic friction plate is sandwiched in at least any of a portion between an inside surface of the pair of support plate portions and an outside surface of the pair of sandwiched portions
Implementation Method 2
an impact absorbing member made of wire material with a base portion, folded portion, and extending portion, which are designed to absorb and distribute impact loads
Implementation Method 3
The base portion is attached to (fixed to or engaged with) the inner column so as to displace together with the inner column when the inner column displaces forward
Data Source
AI summary
A support bracket is arranged inside a slit of an outer column and joined to the inner column so as to be able to detach due to an impact load applied to the inner column at the time of a secondary collision. A base portion of an impact absorbing member is attached to the inner column so as to displace together with the inner column when the inner column displaces toward the front, and a folded portion of the impact absorbing member is made to face a jerking portion of the support bracket in the front-rear direction.