Telescopic Steering Device Shock Absorbing Protuberances
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Solution Overview
Problem
Existing telescopic steering apparatuses face challenges in stably maintaining the inner column radially inside the outer column and effectively absorbing shock loads during collisions at a low cost, due to complex manufacturing processes and increased costs associated with separate energy absorption members.
Innovation Solution
A telescopic steering apparatus with an outer column having an enlargeable and reducable inner diameter, featuring a supporting portion and shock absorbing protuberances formed by expansion processes like hydroforming, which integrates the supporting and shock absorbing functions, reducing the need for separate components and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate energy absorption members are added to absorb shock loads during collisions, then shock absorption performance is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the shock absorption function with the outer column structure by forming shock absorbing protuberances directly on the inner peripheral surface of the outer column. This integration eliminates the need for separate energy absorption members, reducing device complexity while maintaining shock absorption performance during collisions
Solution Approach 2:
The outer column is designed to serve multiple functions: structural support, shock absorption, and radial positioning of the inner column. The shock absorbing protuberances are formed as integral features of the outer column, allowing it to absorb shock loads during collisions without requiring additional dedicated components
2Reliability
If multiple protuberances are provided on the outer column for shock absorption, then shock absorption performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The hydroforming process automatically forms multiple shock absorbing protuberances on the inner peripheral surface of the outer column through controlled plastic deformation. The process self-regulates the formation of protuberances at multiple locations without requiring high-precision manual positioning or assembly, reducing manufacturing precision requirements while ensuring consistent shock absorption performance
3Stability of the object's composition
If the inner column is fitted to the outer column over the entire circumference, then radial stability is improved, but manufacturing cost increases due to extensive cutting work
Solution Approach 1:
Instead of requiring the inner column to fit the outer column over the entire circumference, the patent segments the contact interface by providing shock absorbing protuberances at specific locations on the inner peripheral surface. These localized protuberances create discrete contact points that provide sufficient radial stability while reducing the extent of precision cutting work required on the inner column
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 solution enables stable radial support of the inner column within the outer column and effective shock absorption during secondary collisions at reduced processing, component management, and assembly costs, while maintaining high stiffness and energy absorption performance.
Implementation Method 1
the outer column 12 has an inner peripheral surface provided with shock absorbing protuberances 41, 41 that are formed by plastic deformation
Implementation Method 2
The outer column 12, including the supporting portion 36 and the shock absorbing portion 40, is formed by expanding a hollow pipe radially outwards
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
In the present invention, a telescopic steering device is provided with a steering column having an outer column and an inner column. The inner peripheral surface of the outer column has a support section that supports the inner column. The inner peripheral surface of the outer column further has a shock-absorbing section, located further to one side in the axial direction than one end face of the inner column in the axial direction, the diameter of an inscribed circle of which is smaller than the outer diameter of the inner column. The outer column, including the support section and the shock-absorbing section, and a movable-side bracket are formed integrally by expansion molding.