Variable Wall Thickness Metal Winding Shaft for Roller Blind Systems
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Solution Overview
Problem
The production of conically widened plastic winding shafts for roller blind systems in vehicles is costly and lacks stability, with existing solutions often using cylindrical base bodies and overmoulding, which do not effectively address manufacturing complexity and functional properties.
Innovation Solution
A metal hollow winding shaft with a cone section shape, featuring a variable wall thickness and conical outer and inner surfaces, is produced using a forming process like hot forming or hammering, resulting in improved stability, vibration behavior, and reduced mass, with the option of incorporating a winding spring offset towards the larger diameter side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conically widened plastic winding shafts are produced, then the desired curved movement direction is achieved, but production costs are high and stability is insufficient
Solution Approach 1:
The invention uses a metal hollow shaft (aluminum or steel) instead of plastic to achieve the conical shape, combining the advantages of metal strength and stability with the desired conical geometry for curved fabric movement
Solution Approach 2:
The invention changes the material parameter from plastic to metal and modifies the geometric parameters by creating a hollow conical structure with variable wall thickness, transforming the winding shaft into a more stable component while maintaining the conical shape
2Reliability
If a metal hollow winding shaft with conical shape is produced, then stability and vibration behavior are improved, but manufacturing complexity increases
Solution Approach 1:
The invention employs hot forming or radial hammering processes that directly transform a cylindrical metal tube into a conical hollow shaft with variable wall thickness in one operation, avoiding complex multi-step manufacturing while achieving the desired geometry and structural properties
Solution Approach 2:
The invention replaces traditional mechanical machining processes with thermal-forming or impact-forming processes, substituting complex mechanical operations with more efficient thermomechanical or impact-based shaping methods
3Strength
If wall thickness is increased in areas with smaller outside diameter, then torsional rigidity is improved, but mass distribution becomes unbalanced
Solution Approach 1:
The invention applies variable wall thickness along the conical shaft, with increased thickness at the smaller diameter end to provide localized torsional reinforcement where it is most needed, while maintaining thinner walls elsewhere to balance the overall mass distribution
Solution Approach 2:
The invention continuously varies the wall thickness parameter along the shaft length, creating a gradient structure that optimizes both local strength requirements and global mass distribution for balanced rotational dynamics
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 approach reduces production costs, enhances stability and vibration performance, and achieves a balanced mass distribution, while minimizing machining steps and allowing for efficient mass production of winding shafts with increased torsional rigidity.
Implementation Method 1
The cylindrical metal tube is tapered by impacts effected radially in the direction of the central axis, these impacts, which are preferably automatically generated by a tool, being distributed circumferentially over the cylindrical metal tube. For this purpose, the cylindrical metal tube is preferably rotated during its processing and the concomitant narrowing and, in particular, preferably continuously or stepwise moved further axially.
Data Source
Figure 1~2
AI summary
The winding shaft (20) has a main body (22) formed as a cone-shaped hollow metal part along a winding shaft axis (2), where the main body is provided for receiving a coiled removable sheet (30,30a) of the winding shaft. The wall thickness of the main body is varied along the direction of the winding shaft axis. The wall thickness is enlarged from an end (22a) of the main body with a larger outer diameter towards another end (22b) of the main body with a smaller diameter. The main body is made of aluminum or aluminum alloy. Independent claims are included for the following: (1) a roller blind system with a coil spring received by the winding shaft; and (2) a method for manufacturing winding shaft for a roller blind system.