Air Spring Connector Structure for Low-Force Flanging
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Solution Overview
Problem
Existing air spring designs face challenges in efficiently and cost-effectively flanging the lid edge of flanged plates, particularly as the size of the air spring increases, due to disproportionate forces required and potential damage to corrosion protection layers, as well as increased production costs from cutting radial slots.
Innovation Solution
A two-part design for the connecting part with a flanged plate and a cover insert, featuring a centrally arranged circular opening and an axially offset annular disk-shaped heel edge, allowing for a consistently small wall thickness and reduced forming and holding forces during assembly, while maintaining stability and sealing integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the cover edge is flanged inwards with sharp-edged retaining grooves, then the flanging process can be performed, but the corrosion protection layer is damaged
Solution Approach 1:
A retaining bead is introduced as an intermediary element between the flanging tool and the cover edge. This rounded bead distributes the forming forces over a larger area and prevents direct contact between sharp tool edges and the corrosion protection layer, thereby enabling the flanging process while preserving the corrosion protection.
Solution Approach 2:
The geometry of the retaining feature is changed from a sharp-edged groove to a rounded bead with specific radius (0.5-2mm). This parameter change in the shape and dimensions of the retaining feature allows the flanging process to proceed with reduced stress concentration and without damaging the corrosion protection layer.
2Force
If radial slots are cut in the lid edge to reduce flanging forces, then the flanging process is simplified, but production costs and manufacturing complexity increase
Solution Approach 1:
The problematic radial slots are completely removed from the design. Instead, the invention uses the inherent geometry of the cover edge with a rounded retaining bead that naturally distributes forming forces during flanging, eliminating the need for additional cutting operations and associated costs.
Solution Approach 2:
The lid edge geometry is modified by adding a rounded retaining bead with specific dimensions (radius 0.5-2mm, height 1-3mm) rather than cutting slots. This parameter change in the edge geometry achieves force distribution during flanging without requiring additional manufacturing steps.
3Stability of the object's composition
If the flanged plate wall thickness is increased to ensure stability against bulging, then structural stability is improved, but the forces required for flanging increase disproportionately
Solution Approach 1:
The cover edge is given special local quality through the rounded retaining bead geometry, which concentrates the forming action in a controlled manner. This localized geometric feature allows thin-walled plates to be flanged successfully by distributing forces appropriately at the critical edge region without requiring overall thickness increase.
Solution Approach 2:
The geometry of the cover edge is changed to include a rounded retaining bead with specific radius (0.5-2mm) and height (1-3mm). This parameter change in the edge geometry enables effective flanging of thin-walled plates by controlling stress distribution during the forming process.
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
Enables easy and inexpensive production of air springs with low forming and holding forces, suitable for various sizes, including larger diameters, without compromising stability or sealing, and avoids material flow issues during flanging.
Implementation Method 1
the cover insert (30, 42, 54) is inserted into the opening (26, 26') of the cover base (18, 18') of the flanged plate (16, 16') in the assembled state with a form-fitting connection
Implementation Method 2
a circular, circumferential sealing lip (12, 12') is formed on the inner wall (10, 10') of the end section (6, 6') of the bellows (4, 4') which is pressed against the axial inner wall (40, 52, 64) of the shoulder edge (36, 48, 60) of the cover insert (30, 42, 54) under elastic and/or plastic deformation
Implementation Method 3
a circular, circumferential sealing lip (12, 12') is formed on the inner wall (10, 10') of the end section (6, 6') of the bellows (4, 4') which is pressed against the axial inner wall (40, 52, 64) of the shoulder edge (36, 48, 60) of the cover insert (30, 42, 54) under elastic and/or plastic deformation
Data Source
Figure 1a~1c
Figure 1d
Figure 2a~2c
AI summary
The invention relates to an air spring (2) with a tubular bellows (4) made of an elastomeric material, which is pressure-tightly attached at its upper end section (6) to an upper connection part (14) and at its lower end section to a lower connection part, wherein at least one of the connection parts (14) is designed as a cup-shaped flange plate (16) made of sheet metal prior to assembly, which has a flat cover bottom (18) and a cover rim (20) formed radially outside and bent radially inwards, wherein the cover rim (20) is toroidally flanged inwards during assembly of the air spring (2) by including an end-side annular bead (8) of the bellows (4) and pressing the end section (6) against a sealing surface (40) of the connection part (14).It is provided that the flange plate (16) has a centrally arranged circular opening (26) in its cover base (18), that a circular disc-shaped cover insert (30) has a radially outwardly formed and axially inwardly offset annular disc-shaped shoulder edge (36), and that the cover insert is inserted into the opening (26) of the flange plate (16) from the axial inside with its shoulder edge (36) bearing against the axial inner wall (24) of the cover base (18) in a form-fitting manner.