Steering Column Stop Body for Crash Energy Absorption
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Solution Overview
Problem
Existing adjustable steering columns face issues with energy absorption during crashes due to elastic springback and unintended clamping, which limits the displacement travel and can lead to uncontrolled energy absorption.
Innovation Solution
A steering column design featuring a stop body with a stop face that moves relative to the fixing element pivot axis, allowing for increased spacing in the released position to limit adjustability and ensuring energy absorption in the locked position, preventing clamping and maintaining displacement travel during crashes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rigid stops are used to limit adjusting range, then the adjusting range is limited, but elastic springback occurs leading to unintended clamping and limited displacement travel in crash
Solution Approach 1:
The stop body is designed to change its position dynamically based on the fixing element's state. In the released position, the stop body is spaced from the casing unit to allow full adjusting range. In the locked position, the stop body moves to engage with the casing unit to provide a hard stop, preventing unintended clamping while maintaining controlled displacement travel during crash.
Solution Approach 2:
The spacing between the stop face and the fixing element pivot axis is changed based on the fixing element's position. When the fixing element is in the released position, the spacing is increased to allow full adjusting range. When locked, the spacing is reduced to engage the stop, thereby changing the mechanical parameter of displacement travel to prevent clamping while maintaining crash safety.
2Manufacturing precision
If the stop body is spaced closer to the fixing element pivot axis, then adjusting range is limited, but displacement travel for energy absorption is restricted in crash
Solution Approach 1:
The stop body's position is made dynamic rather than fixed. During normal adjustment operations, the stop body is positioned to limit the adjusting range. During crash, when the casing unit experiences extreme forces, the stop body's design allows it to engage at the appropriate moment to provide the hard stop needed for energy absorption, ensuring the displacement travel is sufficient for safety.
Solution Approach 2:
The stop body is pre-positioned at a specific spacing from the fixing element pivot axis that allows full adjusting range during normal operation. This preliminary positioning ensures that during crash, the stop body will engage at the correct moment to provide the necessary hard stop for energy absorption, without restricting the adjusting range during normal use.
3Ease of operation
If the stop body is spaced farther from the fixing element pivot axis, then full adjusting range is maintained, but unintended clamping occurs due to elastic springback
Solution Approach 1:
The key parameter of spacing between the stop face and fixing element pivot axis is changed based on the operating state. During adjustment operations, the spacing is maintained at a value that allows full adjusting range. When the fixing element transitions to the locked position, the spacing is reduced to engage the stop body, preventing elastic springback and unintended clamping while maintaining full adjusting range during normal operation.
Solution Approach 2:
The stop body acts as an intermediary element between the fixing element and the casing unit. By positioning the stop body at an appropriate spacing from the fixing element pivot axis, it mediates the interaction between these components, allowing full adjusting range during normal operation while preventing unintended clamping by engaging to provide a hard stop when needed.
4Reliability
If the stop body is positioned to engage the casing unit, then displacement travel is limited, but adjusting range is restricted during normal operation
Solution Approach 1:
The stop body's engagement with the casing unit is made dynamic rather than continuous. During normal adjustment operations, the stop body is positioned to remain spaced from the casing unit, allowing full adjusting range. When the fixing element is in the locked position, the stop body engages with the casing unit to provide a hard stop, preventing clamping while maintaining full adjusting range during normal operation.
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
The design ensures reliable energy absorption and maintains full operability during crashes by preventing clamping and ensuring the correct displacement travel, enhancing safety and operational reliability.
Implementation Method 1
a prestressing element, which prestresses the stop body in such a way that the stop body can be transferred
Data Source
AI summary
A steering column may include a casing unit with a steering spindle that is rotatable about a longitudinal axis and a bracket unit that is fixable on the motor vehicle. The casing unit may be secured to the bracket unit such that the casing unit is adjustable in at least one direction. The casing unit may be fixable in different positions by a fixing mechanism. The fixing mechanism may have a fixing element that is rotatable about a pivot axis. The casing unit may be fixed in position in or on the bracket unit in a locked position of the fixing element, and adjusted relative to the bracket unit in a released position of the fixing element. A movably mounted stop body may interact with the fixing element and, in the released position of the fixing element, is disposed in a first position where it limits adjustability of the casing unit relative to the bracket unit. In the locked position of the fixing element, the stop body may be disposed in a second position where it disengages with the casing unit. The stop body may include a stop face, the spacing of which from the pivot axis is greater in the released position than in the locked position.