Accumulator Vessel Structure for Coaxial Thread and Tool Alignment

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Solution Overview

Problem

Conventional metal bellows accumulators in hydraulic circuits require complex assembly and welding, leading to difficulties in achieving coaxial accuracy between thread and tool engagement portions, increasing component count and manufacturing complexity.

Innovation Solution

The accumulator design features a pressure vessel with a first section including a thread portion and a second section formed by a single piece with a tool engagement portion, allowing for improved coaxial accuracy through mate fitting, reducing the number of components, and simplifying the manufacturing process by eliminating separate welding of internal and flange portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the pressure vessel is formed by joining multiple members by welding, then the accumulator can be assembled with separate components, but the coaxial accuracy between the thread portion and tool engagement portion deteriorates and manufacturing complexity increases

Engineering Contradiction:
Improvecomponent assemblyVSAvoidcoaxial accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent merges the first section (containing thread portion) and second section (containing tool engagement portion) into a single integrated pressure vessel formed by joining these sections. This integration ensures coaxial accuracy between the thread portion and tool engagement portion while still allowing separate manufacturing of sections that are subsequently joined, resolving the contradiction between ease of manufacture and manufacturing precision.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If the pressure vessel is formed by joining multiple members by welding, then component assembly is possible, but the number of components and manufacturing time increase

Engineering Contradiction:
Improvecomponent assemblyVSAvoidmanufacturing time
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The pressure vessel is segmented into a first section and a second section that can be manufactured separately and then joined together. This segmentation allows for parallel manufacturing of components, reducing overall manufacturing time while maintaining the ability to assemble complex structures, thus resolving the contradiction between ease of manufacture and productivity.

Inventive Principle:
Principle #1Segmentation

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 configuration enhances coaxial accuracy between the thread and tool engagement portions, reduces manufacturing costs, and simplifies the production process while minimizing the gas chamber volume and fluid sealed within it.

Implementation Method 1

a bellows mechanism including a bellows which is flexible in the longitudinal direction (axial direction) of the shell

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

pressure fluctuation in liquid flowing into the hydraulic circuit and the accumulator is buffered by the swell and shrink function of gas in the gas chamber in response to expansion and contraction of the bellows mechanism

Methodology Applied
Scientific EffectCompressibility:

Data Source

PatentEP3597932B1accumulator
Publication Date: 2021.08.04 NHK SPRING CO LTD
  • EP3597932B1 patent drawingFigure 1
  • EP3597932B1 patent drawingFigure 2
  • EP3597932B1 patent drawingFigure 3

AI summary

An accumulator includes a pressure vessel and a partition portion separating an interior space of the pressure vessel into a liquid chamber and a gas chamber so that a volume ratio between the liquid chamber and the gas chamber in the pressure vessel is variable. The pressure vessel includes a first section including a thread portion for fastening the accumulator to a support member and a second section joined to the first section and formed by a single piece including a tool engagement portion capable of engaging with a tool for rotating the accumulator. The first section and the second section are fitted together by mating portions coaxial with the thread portion and the tool engagement portion.