Telescopic Steering Shaft Bearing Layout for Stroke and Stiffness
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Solution Overview
Problem
Steering devices face challenges in achieving desired vibrational stiffness while maintaining adequate stroke amounts during telescopic operation and secondary collapse, as existing configurations often result in interference and reduced stability.
Innovation Solution
The steering device incorporates an outer and inner shaft with specific bearing configurations, including a non-insertable region with a predetermined bearing interval, to prevent interference and enhance stability, allowing for improved vibrational stiffness and stroke security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the inner shaft is rotatably supported in the outer column positioned on the front side of the vehicle body, and the outer shaft is rotatably supported in the inner column positioned on the rear side of the vehicle body, then the mounting member can be disposed on the movement trajectory, but interference occurs between the inner column or inner shaft and the mounting member during telescopic operation, reducing the stroke amount
Solution Approach 1:
The patent inverts the conventional support configuration by positioning the outer shaft in the outer column on the front side and the inner shaft in the inner column on the rear side, opposite to the traditional arrangement. This inversion eliminates interference between the inner column/shaft and mounting members during telescopic operation, securing the stroke amount while maintaining mounting member accessibility.
2Device complexity
If a single bearing is used to support the inner shaft, then the structure is simple, but the vibrational stiffness is insufficient
Solution Approach 1:
The patent segments the bearing support system into multiple bearings (first bearing and second bearing) distributed along the axial direction of the inner shaft. This segmentation provides multiple support points that enhance vibrational stiffness and stability while maintaining reasonable structural complexity.
Solution Approach 2:
The patent enhances stiffness by distributing bearings along the axial dimension rather than concentrating support at a single location. This dimensional distribution of support points creates a more rigid structure that resists vibrations while allowing telescopic movement.
3Volume of moving object
If the bearing is positioned in the insertable region, then the structure is compact, but interference occurs between the bearing and outer shaft during telescopic operation or secondary collapse
Solution Approach 1:
The patent extracts the bearing from the insertable region and relocates it to the non-insertable region. This extraction eliminates interference between the bearing and outer shaft during telescopic operation and secondary collapse, ensuring reliable operation while maintaining compact overall structure.
Data Source
AI summary
A steering device according to an aspect of the present invention includes an outer shaft, an inner shaft, an outer column, and an inner column. The inner shaft has a sliding portion configured to be capable of being inserted into the outer shaft, and a bearing-mounting portion that is connected to the sliding portion in an axial direction thereof and is configured not to be capable of being inserted into the outer shaft. In the bearing-mounting portion, rear bearings are disposed with an interval therebetween in the axial direction.