Tube Joint Structure for Thick-Wall Microflow Tube Assembly

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Solution Overview

Problem

Existing tube pumps face challenges in durability due to the high rigidity of tubes with sufficient thickness, and in micro-flow applications, the small inner diameter of the tube makes it difficult to insert a joint structure without visually recognizing the channel.

Innovation Solution

A joint unit comprising a resin-made tube with a liquid transferring channel and a joint structure that includes a protrusion with a shaft shape, which forms an insertion groove with the tubular part, allowing the tube to be inserted elastically deformed, without requiring visual recognition of the channel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the tube thickness is increased to obtain sufficient durability against pressing force from roller parts, then the durability is improved, but the rigidity of the tube becomes comparatively high, making it difficult to elastically deform the tube and insert the joint part

Engineering Contradiction:
ImprovedurabilityVSAvoidease of insertion
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The joint structure is divided into distinct functional components: a holding portion that secures the tube externally, and a protrusion that penetrates the tube wall. This segmentation allows the tube to maintain its thickness for durability while the joint structure adapts to insert without requiring excessive deformation of the entire tube.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The protrusion is designed with a tip portion having a smaller outer diameter than the base, creating a localized quality variation. This tapered geometry concentrates the deformation requirement at the tip region, allowing insertion while the rest of the tube maintains its structural integrity and rigidity.

Inventive Principle:
Principle #3Local quality

2Productivity

If the inner diameter of the channel is reduced to achieve extremely micro flow rate (e.g., 0.01 ml/min to 1 ml/min), then the flow rate control is improved, but the operation of inserting the joint part becomes difficult without visual recognition of the channel

Engineering Contradiction:
Improveflow rate controlVSAvoidease of insertion
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The protrusion's tapered geometry enables the joint structure to self-align and self-insert into the tube channel without requiring visual guidance. The decreasing outer diameter from base to tip creates a natural guiding mechanism that facilitates automatic positioning and insertion, even in tubes with extremely small inner diameters.

Inventive Principle:
Principle #25Self-service

3Reliability

If the tube thickness is increased to obtain sufficient durability, then the durability is improved, but the inner diameter of the channel becomes smaller relative to the tube thickness, making insertion more difficult

Engineering Contradiction:
ImprovedurabilityVSAvoidinsertion precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The holding portion is designed to first secure the tube in place before the protrusion attempts to penetrate the tube wall. This preliminary action of external holding stabilizes the tube position and reduces insertion precision requirements, allowing the protrusion to subsequently penetrate the tube wall at the correct location without requiring high precision alignment.

Inventive Principle:
Principle #10Preliminary action

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 joint structure enables easy insertion of the protrusion into the liquid transferring channel, ensuring secure holding and facilitating the assembly process, even in micro-flow applications with small channel diameters.

Implementation Method 1

upon the insertion of the protrusion in the liquid transferring channel, the liquid transferring channel is elastically deformed so that the inner diameter of the liquid transferring channel increases up to a size of the outer diameter of the protrusion

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the outer peripheral surface of the resin-made tube is held by the inner peripheral surface of the tubular part

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3800353B1Joint structure, joint unit and assembly method of joint unit
Publication Date: 2025.04.30 SURPASS IND
  • EP3800353B1 patent drawingFigure 1
  • EP3800353B1 patent drawingFigure 2
  • EP3800353B1 patent drawingFigure 3

AI summary

Provided is a joint structure 100 comprising a main body 110, a tubular part 120 that is formed in a tubular shape to protrude from the main body 110 along an axis X and holds an outer peripheral surface of the resin-made tube 200, and a protrusion 130 that is formed in a shaft shape to protrude from the main body 110 along the axis X and forms, between the protrusion and the tubular part 120, an insertion groove 133 in which the resin-made tube 200 is inserted, the main body 110 and the protrusion 130 are formed with a coupling channel 100a extending along the axis X and coupling a liquid transferring channel 210 and another channel, and a tip of the protrusion 130 is disposed at a position closer to the main body 110 than a tip of the tubular part 120.