Steering System Energy Absorbing Unit Layout
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Solution Overview
Problem
Steering systems with energy absorbing units, such as those described in U.S. Pat. No. 8,375,822, have a low degree of freedom in layout due to the overlapping arrangement of energy absorbing straps and locking cams, which limits the effective use of space around the energy absorbing unit.
Innovation Solution
A steering system design that includes a steering shaft, a column jacket, tooth defining members, and energy absorbing units with separate fold-back portions and coupling mechanisms, allowing the energy absorbing portions to deform and absorb impact energy while effectively utilizing space by guiding the movement of the second tooth defining member between facing edges of the energy absorbing portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the energy absorbing strap and locking cam are arranged to overlap with teeth in meshing engagement, then the energy absorbing function is achieved, but the layout degree of freedom is reduced and space utilization is limited
Solution Approach 1:
The energy absorbing portion is divided into multiple separate portions (first energy absorbing portion and second energy absorbing portion) that are arranged side by side rather than overlapping. Each portion has its own fold-back section and can deform independently, maintaining the energy absorbing function while increasing layout flexibility and space utilization.
Solution Approach 2:
Instead of arranging components in an overlapping configuration (one dimension), the patent utilizes a side-by-side arrangement in the orthogonal direction, effectively using another spatial dimension to resolve the layout constraint and improve space utilization.
2Reliability
If the energy absorbing strap is deformed to absorb impact energy, then the energy absorbing capacity is improved, but the layout space requirement increases
Solution Approach 1:
The energy absorbing function is distributed across multiple separate portions arranged compactly side by side. This segmentation allows each portion to deform independently within a smaller overall footprint, maintaining high energy absorbing capacity while reducing the total layout space required.
Solution Approach 2:
The fold-back sections of the energy absorbing portions are arranged to nest within or adjacent to each other during deformation, allowing the components to absorb impact energy while occupying minimal space in the retracted state.
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 design enhances the energy absorbing capacity by allowing even deformation of energy absorbing portions and stabilizes the orientation of the second tooth defining member, effectively utilizing space and increasing the degree of freedom in the layout of the energy absorbing unit.
Implementation Method 1
each including a restraining portion restrained in a column axial direction by the lower jacket, a first portion extending upward from the restraining portion in the column axial direction, a fold-back portion, and a second portion formed by folding back the energy absorbing portion at the fold-back portion
Implementation Method 2
a second tooth defining member that has second teeth configured to come into meshing engagement with the first teeth
Data Source
AI summary
A steering system includes a second tooth defining member and an energy absorbing unit. The energy absorbing unit includes energy absorbing portions each including a first portion extending upward in a column axial direction from a restraining portion restrained in the column axial direction and a second portion formed by folding back the energy absorbing portion at a fold-back portion, the energy absorbing portions being separated from each other in a first orthogonal direction, and a coupling portion that couples the second portions together and moves together with the second tooth defining member at the time of the secondary collision. At the time of the secondary collision, the energy absorbing portions allow the fold-back portions to move downward in the column axial direction to absorb impact energy while guiding downward movement of the second tooth defining member in the column axial direction between facing edges of the energy absorbing portions.