Bellows Accumulator Cap Structure for Fast Stay Separation

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Solution Overview

Problem

Conventional accumulators face difficulties in prompt separation of the bellows cap from the stay due to reduced elastic restorability of rubber at low temperatures, leading to delayed separation and potential damage from pressure imbalances.

Innovation Solution

The accumulator design incorporates an elastic abutment part with an annular sealing part and a buffering part on the radially inner side, featuring communication passages that ensure a push-up force acts instantaneously and evenly on the bellows cap during pressure boosts, facilitating smooth separation from the stay without unbalanced loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the annular projecting part of the rubber is crushed up to seal the through hole, then the sealing part is protected from pressure imbalance, but the separation of the bellows cap from the stay is delayed due to reduced elastic restorability at low temperatures

Engineering Contradiction:
Improvesealing protectionVSAvoidseparation speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The annular projecting part is divided into two functional segments: a sealing part (flat part) and a buffering part (oblique side part). The buffering part remains in contact with the stay to provide protection, while the sealing part can separate when needed, resolving the contradiction between maintaining protective contact and enabling rapid separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the annular projecting part are given different properties: the sealing part has a flat surface for sealing, while the buffering part has an oblique side that maintains contact with the stay. This local differentiation allows the buffering part to provide continuous protection while the sealing part can separate rapidly under pressure.

Inventive Principle:
Principle #3Local quality

2Strength

If the bellows cap is pressed against the stay to maintain length, then the metal bellows is protected from damage, but the liquid chamber cannot be fully pressurized due to pressure loss through the stay's through hole

Engineering Contradiction:
Improvebellows protectionVSAvoidliquid chamber pressure
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

A valve mechanism is introduced as an intermediary between the liquid chamber and the outside environment. The valve controls fluid communication, allowing pressure to be maintained when closed and enabling controlled discharge when opened, thus resolving the contradiction between maintaining protective contact and achieving full pressurization.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the annular projecting part has only a flat sealing surface, then the structure is simple, but the sealing part deteriorates rapidly due to repeated deformation without buffering protection

Engineering Contradiction:
Improveseal structure simplicityVSAvoidsealing part durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The annular projecting part is segmented into a sealing part and a buffering part. The buffering part absorbs repeated deformation through its oblique side contact with the stay, protecting the sealing part from deterioration while maintaining structural simplicity through integration into a single rubber component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The buffering part is designed to absorb and cushion the repetitive deformation forces before they reach the sealing part. This beforehand cushioning protects the critical sealing surface from wear and deterioration, extending its service life without complicating the overall structure.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 enhances the prompt separation of the bellows cap from the stay, reduces the pressure required for separation, and prevents mechanical damage by distributing the force evenly, improving operational efficiency and reliability, especially in low-temperature environments.

Implementation Method 1

the cap is moved toward the stay by the gas pressure

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Implementation Method 2

liquid pressure acts from the inner side

Methodology Applied
Scientific EffectLiquid pressure: Pressure Increase

Implementation Method 3

a push-up force acts instantaneously and evenly on the bellows cap during pressure boosts

Methodology Applied
Scientific EffectPressure distribution: Pascal's Law

Data Source

PatentEP3404271B1accumulator
Publication Date: 2021.01.27 EAGLE INDS
  • EP3404271B1 patent drawingFigure 1
  • EP3404271B1 patent drawingFigure 2
  • EP3404271B1 patent drawingFigure 3

AI summary

To provide an accumulator having a buffering action for protecting a sealing part from a stay, in which a bellows cap can be promptly separated from the stay at the time of a pressure boost in a pressure pipe. In a pressure container (2), a tubular bellows (6), a bellows cap (10) divisionally defining a liquid chamber (M) and a gas chamber (G) in cooperation with the bellows, and a through hole (33) are provided, and a stay (30) partitioning the liquid chamber (M) into a closed liquid chamber (Mc) on a side of the bellows (6) and an open liquid chamber (Mo) on a side of the liquid pressure port is provided, the bellows cap (10) includes an elastic abutment part (23) provided with an annular sealing part (25) positioned around the through hole (33) to face the through hole, and a buffering part (26) positioned on a radially inner side of the sealing part (25), and communication passages (27A) always communicating with the through hole (33) are formed in the buffering part of the elastic abutment part (23).