Motor Vehicle Roller Blind Shaft With Axial Length Compensation
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Solution Overview
Problem
Roller blind arrangements for motor vehicle sunroofs face issues with stress and wear due to temperature and humidity fluctuations, leading to increased actuation forces and potential wedging of the lateral guiding mechanism, as well as ripples and crinkles in the roller blind web.
Innovation Solution
A roller blind arrangement with a hollow tube winding shaft featuring axial sliding connections between the middle tube and bearing bushes, allowing for length compensation without introducing excessive stress, and incorporating a coupling element for co-rotation and torsion transmission, along with guiding elements for secure positioning and length adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the hollow tube arrangement is made from a plastic tube, then it provides flexibility and ease of manufacture, but temperature and humidity fluctuations cause length changes that introduce stress and damage connections
Solution Approach 1:
The bearing bushes are designed to be axially displaceable relative to the middle tube, allowing the system to dynamically adjust to length changes of the plastic tube caused by temperature and humidity fluctuations. This dynamic adjustment prevents stress buildup and connection damage while maintaining the ease of manufacture benefits of using a plastic tube.
Solution Approach 2:
The patent changes the positional parameter of the bearing bushes along the axial direction, allowing them to move to different positions relative to the middle tube. This parameter change enables the system to accommodate length variations of the plastic tube without introducing excessive stress, thereby maintaining connection reliability.
2Productivity
If the winding spring pre-loads the bearing sleeve and middle tube, then the roller blind web is automatically wound onto the winding shaft, but this causes ripples and crinkles in the roller blind web and excessive one-sided wear
Solution Approach 1:
The axially displaceable bearing bushes allow the pre-loading force from the winding spring to be distributed more evenly along the axial direction. As the bearing bushes can move axially, they adjust to accommodate the rolling motion of the blind web, preventing concentration of stress at single points that would cause ripples and crinkles, while still maintaining automatic winding functionality.
3Device complexity
If the bearing bushes are fixed to the middle tube, then structural simplicity is maintained, but temperature-induced length changes cause excessive stress and potential wedging of the lateral guiding mechanism
Solution Approach 1:
The bearing bushes are designed with axial displacability while maintaining rotational connection through the coupling element. This dynamic design allows the system to accommodate thermal expansion and contraction of the plastic middle tube without requiring complex adjustment mechanisms, thus managing stress levels while preserving relatively simple structure.
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 minimizes stress-related issues by compensating for length changes in the hollow tube due to temperature and humidity fluctuations, ensuring smooth operation and reducing wear on the roller blind web.
Implementation Method 1
Fluctuations in temperature and/or humidity may cause the length of the hollow tube arrangement to change
Implementation Method 2
Fluctuations in temperature and/or humidity may cause the length of the hollow tube arrangement to change
Data Source
AI summary
A roller blind arrangement for a motor vehicle may have a roller blind web which has guiding tapes on its lateral edges on either side of a longitudinal center plane of the roller blind, a winding shaft onto which the roller blind web can be wound or from which the roller blind web can be unwound and which comprises a flexible hollow tube arrangement penetrated by a vehicle-attached mounting beam and comprising a flexible middle tube which is provided with bearing bushes in a co-rotating manner on both ends, each guiding tape of the roller blind web being attached to one bearing bush. At least one of the bearing bushes can shift relative to the middle tube in the longitudinal direction of the hollow tube.