Steering Apparatus Bifurcated Arm Linking Structure
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Solution Overview
Problem
Conventional steering apparatuses with tilt/telescopic adjustment mechanisms face interference issues during telescopic adjustments, leading to reduced rigidity and potential disturbances in the movement of the lower shaft and universal joint, particularly when the lower shaft on the vehicle's front side extends and contracts.
Innovation Solution
The design incorporates bifurcated arm-shaped portions with first and second linking portions that protrude in an up-down direction, where the second linking portion protrudes more than the first, forming circular arc shapes with different radii of curvature, allowing the lower shaft, upper shaft, and universal joint to move without interference during telescopic adjustments, enhancing the rigidity and assembly of the steering apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single linking portion is provided between the arm-shaped pieces of the bifurcated arm-shaped portion, then the structure is simple, but the lower shaft and universal joint may interfere with the linking portion during telescopic adjustment, disturbing the movement operation
Solution Approach 1:
The single linking portion is divided into two separate linking portions: a first linking portion and a second linking portion. This segmentation allows the lower shaft and universal joint to pass through the space between them during telescopic adjustment, preventing interference while maintaining structural integrity. The bifurcated arm-shaped portion now has two distinct linking regions that work together to accommodate the moving components.
Solution Approach 2:
The two linking portions are positioned at different locations along the axial direction of the outer column, creating a spatial arrangement that provides clearance for the lower shaft and universal joint. By distributing the linking functions across different positions, the design creates a three-dimensional pathway that allows movement without interference.
2Strength
If the bifurcated arm-shaped portion is designed with high rigidity, then the structural strength is improved, but the lower shaft and universal joint may interfere with the arm-shaped pieces during telescopic adjustment
Solution Approach 1:
The rigid bifurcated arm-shaped portion is segmented into two separate linking portions that are spaced apart. This segmentation maintains the overall rigidity of the arm-shaped pieces while creating a clearance zone between the linking portions through which the lower shaft and universal joint can move during telescopic adjustment.
Solution Approach 2:
The space between the first and second linking portions acts as an intermediary zone that accommodates the lower shaft and universal joint during movement. This intermediate space allows the rigid arm-shaped structure to coexist with the moving components without interference.
3Adaptability or versatility
If the lower shaft is allowed to extend and contract during telescopic adjustment, then the telescopic function is achieved, but the universal joint moves greatly in the axial direction, causing potential interference with the linking portion
Solution Approach 1:
The linking structure is segmented into two separate portions that create a clearance zone. This segmentation allows the universal joint and lower shaft to move axially during telescopic adjustment without interfering with the linking portions, as the two linking portions are positioned to accommodate the range of motion.
Solution Approach 2:
The linking portions are arranged in the axial direction at different positions, creating a three-dimensional pathway that accommodates the axial movement of the universal joint and lower shaft during telescopic adjustment.
Data Source
AI summary
A steering apparatus includes: a fixed bracket; an outer column; an arm portion; a column pipe; a steering shaft A including an upper shaft rotatably attached to the column pipe and a lower shaft which is connected by an universal joint and in which a male shaft and a female shaft engage with each other so as to freely extend and contract; and a fastening tool. The arm portion includes: bifurcated arm-shaped portions that extend from a front side in the axial direction of the outer column toward an outer side in the axial direction; a first linking portion formed between the arm-shaped portions so as to protrude upward from upper edges of the arm-shaped portions; and a second linking portion that protrudes downward from lower edges of the arm-shaped portions, and the second linking portion protrudes from the arm-shaped portions by a larger amount than the first linking portion.