Bellows Fold Geometry to Prevent Adhesion Under Compression
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Solution Overview
Problem
Existing bellows designs face issues with fold walls adhering or sticking together during high compression and rotational loading, which compromises their elasticity and functionality.
Innovation Solution
The bellows design features alternating outer fold diameters and coordinated convex-concave shaping of fold walls to prevent contact between adjacent folds, even under maximum compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bellows is highly compressed to achieve greater elasticity and protection, then the protective function is improved, but the fold walls come into contact and adhere to each other, compromising functionality
Solution Approach 1:
The fold walls are pre-shaped with specific curvatures (convex and concave shapes) to ensure that during compression, the curved surfaces guide the folds past each other without flat contact. This curvature design prevents adhesion by eliminating large contact areas between adjacent folds, allowing the bellows to achieve high compression (up to 75%) while maintaining functionality.
2Force
If the fold walls are made rectilinear or pre-shaped to achieve preferred force direction, then the force action is improved, but the risk of contact and adhesion increases under high compression
Solution Approach 1:
Different regions of the fold wall are given different curvatures: some regions are convex while adjacent regions are concave. This local variation in geometry ensures that force can be directed as needed while simultaneously preventing contact between folds during compression, as the alternating curvatures create clearance between adjacent fold surfaces.
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 allows for high compression of up to 75% without fold wall contact, enhancing the bellows' elasticity and preventing adhesion, ensuring reliable protection against dirt and moisture.
Implementation Method 1
The bellows is formed from an elastic material, for example a rubber mixture, and has a cylinder jacket as the basic shape... The bellows is therefore designed to be correspondingly highly elastic in the working direction because of the expansion or closing of the folds.
Implementation Method 2
The fold wall of the one fold with the smaller second fold diameter is pre-shaped convexly, i.e., curved outward. By contrast, the fold wall of the adjacent fold with the larger third fold diameter is pre-shaped concavely, i.e. curved inward, at least in the overlapping region... the two fold walls are preferably shaped in such a manner that, even in the maximally compressed state, the convex fold wall still remains free from contact or at maximum with punctiform contact.
Data Source
AI summary
A bellows formed from an elastic material with a cylinder jacket as a basic shape, a cylinder axis corresponding to a working direction, and a jacket surface shaped into a plurality of folds transversely with respect to the working direction. Each fold has a first fold diameter perpendicular to the working direction and spaced apart therefrom in the working direction, a second fold diameter differing from the first fold diameter and spaced apart therefrom in the working direction, against the first fold diameter, and a fold wall formed integrally therewith. Consecutive folds in the working direction each have the same inner fold diameter, but alternating different outer fold diameters.