Electric valve and assembly method thereof

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Solution Overview

Problem

The existing electric valve assembly methods face challenges in maintaining coaxiality and assembly accuracy due to the phenomenon of melted brazing material rising along the outer periphery of the valve seat, leading to reduced yield and controllability.

Innovation Solution

The method involves forming a constricted portion, such as a triangular groove or convex portion, on the outer peripheral surface of the valve seat to prevent the brazing material from rising, allowing for improved positioning and alignment of components during assembly, ensuring enhanced coaxiality and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the valve seat is soldered to the valve main body in an upside down state, then the valve seat can be fixed to the valve main body, but the melted brazing material rises along the outer periphery of the valve seat causing positioning inaccuracy

Engineering Contradiction:
Improvebonding strengthVSAvoidpositioning accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

A constricted portion is formed on the outer peripheral surface of the valve seat before the soldering process. This preliminary structural modification prevents the brazing material from rising along the outer periphery during the upside-down soldering operation, thereby maintaining positioning accuracy while still achieving proper bonding.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The constricted portion creates a localized variation in the outer peripheral surface of the valve seat. This local structural change restricts the flow of brazing material to specific areas while allowing proper bonding in other regions, thus resolving the conflict between bonding strength and positioning accuracy.

Inventive Principle:
Principle #3Local quality

2Strength

If the brazing material is allowed to rise and cure in an upward raised state, then complete bonding is achieved, but the positioning reference cannot be ensured and assembly accuracy is deteriorated

Engineering Contradiction:
Improvebonding completenessVSAvoidassembly accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The constricted portion is prepared in advance on the valve seat outer periphery. During the soldering process, this pre-formed structure guides the brazing material to cure in a controlled manner, ensuring both complete bonding and accurate positioning reference for subsequent assembly steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The constricted portion creates a localized barrier that controls where the brazing material can rise and cure. This local restriction ensures that the brazing material forms a proper bond while maintaining a clean, accurate outer periphery that serves as a reliable positioning reference.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the valve seat is fixed by a jig after soldering, then the assembly can proceed, but the positioning reference is compromised due to brazing material rise

Engineering Contradiction:
Improveassembly feasibilityVSAvoidpositioning reference accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The constricted portion is formed before assembly, preparing the valve seat to maintain its positioning reference integrity throughout the soldering and assembly process. This preliminary structural feature ensures that when the valve seat is fixed by the jig, accurate positioning is maintained.

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

This configuration effectively restricts the rise of brazing material, enhancing the assembly accuracy and controllability of the electric valve, leading to improved durability and yield by ensuring accurate alignment of the valve shaft and seat components.

Implementation Method 1

a melted brazing material rises along the outer periphery of the valve seat by a phenomenon such as surface tension

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP3315835B1Electric valve and assembly method thereof
Publication Date: 2020.03.18 FUJIKOKI CORP
  • EP3315835B1 patent drawingFigure 1A~1B
  • EP3315835B1 patent drawingFigure 2~4
  • EP3315835B1 patent drawingFigure 5

AI summary

[Object] To provide an electric valve capable of restricting a phenomenon in which a melted brazing material rises along an outer periphery of a valve seat and an assembly method thereof. [Solving Means] An electric valve includes: a valve shaft provided with a valve body; a valve seat provided with a valve seat portion with which the valve body comes into contact and from which the valve body separates; a valve main body having the valve seat fixed thereto by soldering; and a stepping motor with a rotor and a stator for elevating the valve shaft, in which a constricted portion is provided at an outer peripheral surface of a side surface of the valve seat.