Flow Path Switch Valve Geometry for Beam Rigidity

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Solution Overview

Problem

The existing flow channel switching valves face a rigidity issue due to thinner beam parts caused by resin flow meeting at the corner portion between the vertical and transverse holes during injection molding, leading to weld lines and reduced structural integrity.

Innovation Solution

The flow channel switching valve design features a valve member with a polygonal vertical hole, such as triangular, quadrangular, or hexagonal shapes, where the corner portions are shifted from the beam part between the transverse and vertical holes, and the valve member is resin-molded with a gate mark only on the outer surface, avoiding thinner beam parts and simplifying the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the vertical through hole has a corner portion at the beam part between the vertical through hole and the transverse hole, then the valve member can be manufactured by injection molding, but the beam part becomes thinner and resin flows meet, generating weld lines and decreasing rigidity

Engineering Contradiction:
Improveinjection molding feasibilityVSAvoidbeam part rigidity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent applies local quality by making the vertical hole have a polygonal shape (triangle, quadrangle, hexagon, or octagon) with corner portions positioned away from the beam parts. This local geometric modification ensures that resin flows do not meet at the beam parts during injection molding, preventing weld line formation and maintaining beam rigidity, while still allowing successful injection molding of the valve member.

Inventive Principle:
Principle #3Local quality

2Device complexity

If the corner portion of the vertical through hole is disposed in the beam part, then the valve member structure is simple, but weld lines are generated and rigidity decreases

Engineering Contradiction:
Improvevalve member structureVSAvoidbeam part integrity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies asymmetry by positioning the corner portions of the polygonal vertical hole away from the beam parts, creating an asymmetric distribution of hole corners relative to the beam structures. This asymmetric positioning prevents resin flow convergence at critical beam areas, eliminating weld lines and maintaining structural integrity while preserving overall design simplicity.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3922889B1Flow path switch valve
Publication Date: 2024.10.23 FUJIKOKI CORP
  • EP3922889B1 patent drawingFigure 1
  • EP3922889B1 patent drawingFigure 2
  • EP3922889B1 patent drawingFigure 3

AI summary

[Object] To provide a flow channel switching valve that can effectively suppress decreasing the rigidity of a beam part of a valve member. [Solution] In a flow channel switching valve 1, a ball valve member 20 has a first opening 21, a second opening 22, and a third opening 23 in communication with a switching flow channel 25 formed in the ball valve member 20, and a valve shaft insertion hole 24 in which a valve shaft 50 is inserted. The valve shaft insertion hole 24 has outward convex corner portions 24a, and the corner portions 24a are shifted from a beam part 26a between the first opening 21 and the valve shaft insertion hole 24, a beam part 26b between the second opening 22 and the valve shaft insertion hole 24, and a beam part 26c between the third opening 23 and the valve shaft insertion hole 24.