One-Piece Metallic Bellows for Pressure Pulsation Damping

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Solution Overview

Problem

Existing accumulators for damping pressure pulsations have complex production processes due to segmented bellows that require welding, leading to uneven flexural rigidity, potential leaks, and reduced service life.

Innovation Solution

A one-piece metallic bellows with a thickness of 0.1 to 0.3 mm, made from materials like stainless steel, eliminates the need for welding and ensures homogeneous flexural rigidity, preventing leaks and allowing for cost-effective, long-lasting operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the bellows is made of segmented parts that are welded together, then the production process becomes complex and time-consuming, but the structural integrity and sealing performance deteriorate due to weld seams causing uneven flexural rigidity and potential leaks

Engineering Contradiction:
Improveproduction processVSAvoidsealing performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies the merging principle by transitioning from a segmented bellows structure with multiple weld seams to a one-piece bellows structure. The entire bellows is formed as a single continuous metallic component, eliminating all weld joints. This merging of segments into one unified structure simultaneously simplifies production (by removing welding steps) and improves reliability (by eliminating leak paths at weld seams), directly resolving the technical contradiction.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If the bellows is made of segmented parts requiring welding, then the manufacturing time increases, but the service life decreases due to uneven stress distribution at weld seams

Engineering Contradiction:
Improvemanufacturing timeVSAvoidservice life
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The one-piece construction merges all bellows segments into a single continuous metallic component, eliminating the need for welding operations. This not only reduces manufacturing time and increases productivity but also ensures uniform stress distribution throughout the structure during operation, preventing premature failure at weld joints and significantly extending the service life of the bellows.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If weld seams are made as identical as possible to ensure symmetrical deformation, then the manufacturing precision requirements increase and production complexity increases, but the flexural rigidity becomes non-uniform due to welding variations

Engineering Contradiction:
Improveweld seam uniformityVSAvoidflexural rigidity uniformity
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

By merging the bellows into a one-piece structure, the patent eliminates all weld seams and the associated manufacturing precision challenges. The uniform flexural rigidity is achieved inherently through the continuous metallic construction, where material properties and geometry can be controlled consistently throughout the entire bellows without the variability introduced by welding processes.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If the bellows is made from thinner material to allow easier deformation, then the deformability improves, but the pressure resistance decreases

Engineering Contradiction:
ImprovedeformabilityVSAvoidpressure resistance
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies parameter changes by optimizing the metallic layer thickness to a specific range (0.1 to 0.3 mm) that balances deformability and pressure resistance. Additionally, the one-piece construction method fundamentally changes the structural parameters, creating a uniform geometry that distributes stresses evenly throughout the bellows, allowing thinner material to achieve both high deformability and adequate pressure resistance simultaneously.

Inventive Principle:
Principle #35Parameter changes

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

The one-piece bellows design provides reliable, long-lasting damping of pressure pulsations with reduced material stress and improved durability, suitable for direct injection systems in vehicles, enhancing engine performance and reducing noise.

Implementation Method 1

the bellows is made of a metallic layer which has a thickness of 0.1 to 0.3 mm... allows the gas volume within the bellows to expand without any problems after it has been compressed

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the bellows delimiting a second volume which can be changed by deformation of the bellows

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP1918626B1Accumulator for damping pressure pulsations
Publication Date: 2010.03.03 CARL FREUDENBERG KG
  • EP1918626B1 patent drawingFigure 1
  • EP1918626B1 patent drawingFigure 2

AI summary

The accumulator has a housing (1). The housing defined a volume (2), which is absorbed within its bellows (3). The bellows defined another volume (4), which is changed by distortion the bellows. The bellows is formed a piece. The bellows is manufactured from a metallic coating, which has thickness from 0.1 to 0.3 millimeter.