Vehicle Steering Column Tube Weight Reduction via Nested Material Design
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Solution Overview
Problem
Existing steering devices for vehicles face challenges in reducing weight and saving space due to the need for high specific gravity materials in both inner and outer tubes to support and rotate the steering shaft, making it difficult to absorb energy and adjust the steering wheel position effectively.
Innovation Solution
A steering device with a telescopic mechanism that includes an outer tube made of metal and an inner tube made of a low specific gravity material like aluminum alloy, where the inner tube is accommodated within the outer tube, and a holding member and driving mechanism allow relative movement of the outer tube with respect to the inner tube when a load is applied, enabling energy absorption and adjustment of the steering wheel position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If both the inner tube and outer tube are made of high specific gravity materials like iron to ensure rigidity and support the steering shaft, then the required rigidity and support function are achieved, but the weight of the steering device increases significantly
Solution Approach 1:
The patent applies different material properties to different parts: the outer tube uses high specific gravity material (iron) for rigidity, while the inner tube uses low specific gravity material (aluminum alloy) for weight reduction. This local differentiation of material quality resolves the contradiction between overall rigidity and weight reduction.
Solution Approach 2:
The patent creates a composite structure by combining two different materials (iron outer tube and aluminum alloy inner tube) into a single functional assembly. This composite approach allows the system to achieve both the rigidity of iron and the lightness of aluminum alloy simultaneously.
2Stability of the object's composition
If both tubes are made of high specific gravity materials to ensure structural integrity, then the steering shaft is properly supported, but the space occupied by the steering device increases
Solution Approach 1:
The patent applies different material properties to different parts: the outer tube uses high specific gravity material (iron) for rigidity, while the inner tube uses low specific gravity material (aluminum alloy) for weight reduction. This local differentiation of material quality resolves the contradiction between overall rigidity and weight reduction.
Solution Approach 2:
The patent places the inner tube inside the outer tube, creating a nested structure. This nesting arrangement reduces the overall volume and space occupation of the steering device while maintaining the structural integrity provided by the iron outer tube.
3Weight of moving object
If the inner tube is made of low specific gravity material like aluminum alloy to reduce weight, then the weight of the steering device decreases, but the rigidity and support capability may be insufficient
Solution Approach 1:
The patent applies different material properties to different parts: the outer tube uses high specific gravity material (iron) for rigidity, while the inner tube uses low specific gravity material (aluminum alloy) for weight reduction. This local differentiation of material quality resolves the contradiction between overall rigidity and weight reduction.
Solution Approach 2:
The patent creates a composite structure by combining two different materials (iron outer tube and aluminum alloy inner tube) into a single functional assembly. This composite approach allows the system to achieve both the rigidity of iron and the lightness of aluminum alloy simultaneously.
4Ease of manufacture
If the outer tube is made of weldable iron to ensure manufacturability and structural strength, then the ease of manufacture and strength are improved, but the weight and space increase
Solution Approach 1:
The patent applies different material properties to different parts: the outer tube uses high specific gravity material (iron) for rigidity, while the inner tube uses low specific gravity material (aluminum alloy) for weight reduction. This local differentiation of material quality resolves the contradiction between overall rigidity and weight reduction.
Data Source
AI summary
A steering device of a vehicle includes: a column housing supported on a vehicle body; a column tube supported to be movable in an axial direction with respect to the column housing and configured to accommodate a steering shaft; and a telescopic mechanism configured to drive the column tube with respect to the column housing in the axial direction. The column tube includes outer and inner tubes, and is configured to allow a relative movement of the outer tube with respect to the inner tube in the axial direction when a load equal to or larger than a predetermined value is applied to the steering shaft. The telescopic mechanism includes a holding member, and a driving mechanism, and is configured to drive the inner and outer tubes with respect to the column housing in the axial direction by the driving mechanism.