Two-Part Rolling Piston With Integrated Axial Buffer Support

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Solution Overview

Problem

Existing rolling pistons for air springs either weigh too much and are expensive due to heavy sheet steel construction or lack comfort due to insufficient usable air volume in lightweight plastic designs without an integrated end stop.

Innovation Solution

A two-part rolling piston with an integrated axial support system, where the upper and lower parts are connected airtight and feature tubular support parts with rib-like stiffening elements, allowing for efficient force absorption and reduced material usage, particularly in plastic materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If heavy sheet steel construction is used for the rolling piston, then the end stop (buffer support) and structural strength are ensured, but the weight and manufacturing cost increase significantly

Engineering Contradiction:
Improvestructural strengthVSAvoidpiston weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The rolling piston is divided into multiple functional segments: the hollow piston body for air volume, the integrated buffer support for end-stop function, and the sealing elements. This segmentation allows each part to be optimized independently - the piston body can be lightweight plastic while maintaining strength through its hollow structure and strategic material placement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of making the entire piston from heavy sheet steel, the invention applies material and structural properties locally - the hollow piston body provides air volume and basic strength, while the buffer support area receives specialized reinforcement and geometry to handle axial loads. This local quality approach ensures strength where needed without unnecessary weight elsewhere.

Inventive Principle:
Principle #3Local quality

2Weight of moving object

If lightweight one-piece plastic piston is used, then the weight and manufacturing cost are reduced, but the usable piston air volume is lost and comfort decreases

Engineering Contradiction:
Improvepiston weightVSAvoidusable piston air volume
Core Design Contradiction:
Weight of moving objectVSVolume of moving object

Solution Approach 1:

The buffer support is nested within the hollow piston body structure, with the buffer support positioned inside the piston's internal volume. This nesting arrangement allows the buffer support to occupy only the necessary space for its function while the remaining hollow volume is fully available for air storage, maximizing the usable air volume while maintaining structural integrity.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Weight of moving object

If two-piece plastic piston without buffer support is used, then the weight is reduced and manufacturing is simplified, but the end stop function is missing reducing comfort

Engineering Contradiction:
Improvepiston weightVSAvoidend stop function
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The buffer support function is merged with the piston structure by integrating the buffer support into the piston body. This integration ensures the end-stop function is reliably provided as part of the piston assembly, eliminating the need for separate buffer components while maintaining the lightweight plastic construction and simplified manufacturing advantages.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2704912B1Rolling piston for an air spring rolling bellows
Publication Date: 2018.11.07 CONTITECH LUFTEDERSYSTEME GMBH
  • EP2704912B1 patent drawingFigure 1
  • EP2704912B1 patent drawingFigure 2
  • EP2704912B1 patent drawingFigure 3

AI summary

A rolling piston (1) for an air spring rolling bellows, the interior (2) of which is connected to the interior of the air spring and which consists of at least two parts, namely a cup-shaped piston lower part (4) and a piston upper part (5) connected in an air-tight manner to the piston lower part, wherein a support (11) for a stop buffer is integrated in the rolling piston, the support consisting of two interacting parts, of which one part (13) is designed as part of the piston upper part and the other part (14) is designed as part of the cup-shaped piston lower part and as emerging from the base thereof, and both support parts interact in order to absorb forces acting substantially axially.