Motor Vehicle Functional Part Drive with Wrap Springs for Play-Free Motion
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Solution Overview
Problem
Existing drive arrangements for motor vehicle functional parts, such as rear spoilers, experience play due to gear mechanisms, which is perceived as a quality issue by users.
Innovation Solution
A compact wrap spring arrangement is integrated on the gear mechanism output side, with two wrap spring members acting in opposite directions, one wrapping around the adjusting shaft and the other around a stationary housing part, eliminating play by supporting torque and allowing rotational transitions between positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a gear mechanism arrangement is used to transfer rotational motion from the drive motor to the adjusting member, then the drive arrangement can achieve mechanical advantage and controlled motion, but play is introduced into the system which is perceived as disruptive by the user
Solution Approach 1:
A wrap spring arrangement is introduced as an intermediary element between the drive shaft and the adjusting member. This wrap spring arrangement comprises a first wrap spring member and a second wrap spring member that act in opposite directions, engaging with the drive shaft and the adjusting member respectively. The wrap spring arrangement eliminates play while preserving the mechanical advantage provided by the gear mechanism, thereby resolving the contradiction between power transmission and play-free operation.
2Ease of operation
If wrap spring members are arranged on the drive shaft to provide rotational direction locking, then locking in one direction and freewheeling in the other direction is achieved, but the arrangement becomes less compact and more complex
Solution Approach 1:
The wrap spring arrangement is merged with the existing drive shaft structure. The first wrap spring member engages with the drive shaft while the second wrap spring member engages with the adjusting member, combining the locking function with the existing compact drive arrangement. This integration maintains the rotational direction locking functionality while minimizing additional complexity and preserving compactness.
3Reliability
If a compact wrap spring arrangement is integrated on the gear mechanism output side, then play is eliminated and operational feel is enhanced, but the device complexity increases
Solution Approach 1:
The wrap spring members are arranged in a nested configuration around the drive shaft and adjusting member. The first wrap spring member is positioned to engage with the drive shaft, while the second wrap spring member is positioned to engage with the adjusting member, with both members nested within the existing housing structure. This nesting approach eliminates play while minimizing the increase in device complexity by utilizing the existing spatial envelope.
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 solution provides a compact and play-free drive arrangement that enhances the operational feel of motor vehicle functional parts by ensuring smooth transitions between closed and open positions without user-perceived disruptions.
Implementation Method 1
a wrap spring arrangement comprising two wrap spring members, which act in opposite directions
Data Source
AI summary
A drive arrangement for a motor vehicle functional part includes: a housing, in which a drive motor, a gear mechanism and an adjustor are provided at least partially; a drive shaft configured to transfer the adjustor via the gear mechanism from a closed position into an open position and vice versa; and a wrap spring arrangement comprising two wrap spring members, which act in opposite directions. The wrap spring arrangement is arranged on a gear mechanism output side, in a region of the adjustor.