Steering Column Recess Clamping Dynamics
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Solution Overview
Problem
Mechanically adjustable steering columns face a technical conflict between easy adjustment and rigid fixation, exacerbated by the need to absorb impact energy and limited installation space, with previous solutions like plastic injection between jacket pipes being unsuitable.
Innovation Solution
The outer jacket tube features a recess with a variable hollow cross-section, enabled by a clamping device, allowing easy longitudinal adjustment and secure rigid fixation, along with a force transmission element like a clamping plate to enhance clamping forces and absorb accident-related forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the clamping device is released to allow easy adjustment of the inner jacket tube, then the adjustment force is reduced and adjustment becomes comfortable, but the rigidity and natural frequency of the steering column deteriorates
Solution Approach 1:
The hollow cross-section of the outer jacket tube is made dynamically changeable through a recess that can be opened or closed by the clamping device. When the clamping device is released, the recess opens to reduce adjustment force; when clamped, the recess closes to maximize rigidity. This dynamic structural change allows the same structure to serve both adjustment and rigidity requirements.
2Ease of operation
If the hollow cross section of the outer jacket tube is enlarged to facilitate adjustment, then adjustment ease improves, but the rigidity and impact energy absorption capability deteriorates
Solution Approach 1:
The recess in the outer jacket tube enables dynamic modification of the hollow cross-section. During adjustment, the recess is open to reduce friction and enable smooth movement. During normal operation and impact events, the clamping device closes the recess to restore full structural rigidity and impact energy absorption capability, thus resolving the contradiction between adjustment ease and structural strength.
3Strength
If the clamping device provides strong clamping force to ensure rigid fixation, then the rigidity improves, but the adjustment force required increases making adjustment difficult
Solution Approach 1:
The recess is extracted from the outer jacket tube structure, creating a localized area where material is removed to form a cavity. This extracted portion allows the clamping device to apply clamping force in a controlled manner - strong enough for rigid fixation when engaged, but allowing easy release when the clamping mechanism is disengaged, thus resolving the contradiction between strong fixation and easy adjustment.
4Manufacturing precision
If plastic injection is provided between jacket pipes to compensate for tolerances, then the fixation precision improves, but the device complexity and installation space requirements increase
Solution Approach 1:
The recess in the outer jacket tube enables the clamping device to self-adjust and compensate for manufacturing tolerances between the inner and outer jacket tubes. The flexible clamping mechanism can adapt to tolerance variations without requiring additional tolerance compensation components like plastic injections, thus achieving precise fixation while maintaining structural simplicity.
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 achieves a high degree of rigidity and natural frequency while ensuring easy adjustment and secure fixation, eliminating the need for additional tolerance compensation, thus optimizing the steering column's performance in both adjustment and impact absorption.
Implementation Method 1
the required sliding fit between the inner and the outer casing tube is as rigid as possible by means of the clamping device
Implementation Method 2
a force transmission element, in particular a clamping plate, is provided between a clamping element of the clamping device and the outer jacket tube
Data Source
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AI summary
The invention relates to a steering column for a motor vehicle, with an inner casing tube (14) receiving a steering spindle (16), which inner casing tube is received so as to be adjustable longitudinally in an outer casing tube (12) having a hollow cross-section and retained on a steering console, and with a clamping device (22), by means of which the inner casing tube (14) can be detachably fixed in its adjusted longitudinal position relative to the outer casing tube (12), wherein the outer casing tube (12) has a cutout (26) at least over one longitudinal region, whereby the hollow cross-section of the outer casing tube can be changed by means of the clamping device (22).