Pilot valve and switching valve

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Solution Overview

Problem

The insecure connection between the inlet pipe and the valve body in brazing processes of pilot valves is due to the welding ring expanding and causing solder to be positioned far from the connection, leading to instability.

Innovation Solution

A snap-fit part, specifically an annular snap groove, is formed on the valve body or inlet pipe to facilitate the snapping of a welding ring, ensuring it remains in place during brazing, thereby allowing solder to flow into the connection, enhancing stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the welding ring is melted during brazing, then the solder can flow and form a joint, but the welding ring expands under stress causing the solder to be positioned far from the connection, resulting in an insecure connection

Engineering Contradiction:
Improveconnection strengthVSAvoidsolder position accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The snap-fit part is designed to preliminarily position the welding ring at the correct location before brazing occurs. This preliminary positioning ensures that when the welding ring is melted and expands, the solder still flows to the correct connection point, resolving the contradiction between allowing expansion and maintaining position accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The snap-fit part acts as an intermediary structure between the welding ring and the connection point. It provides a mechanical constraint that guides the welding ring's position while allowing controlled expansion, ensuring solder flows to the correct location despite thermal expansion during brazing

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the welding ring is constrained to prevent expansion, then solder position accuracy improves, but the brazing process becomes more difficult and the connection may become insecure due to stress

Engineering Contradiction:
Improvesolder position accuracyVSAvoidbrazing process ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The snap-fit part is designed with specific dimensional parameters that allow controlled constraint. The fit tolerance and geometry are optimized to provide enough constraint for positioning accuracy while maintaining ease of assembly and brazing, transforming the constraint from overly restrictive to optimally controlled

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If a complex positioning structure is used to maintain welding ring position, then connection stability improves, but the device complexity increases

Engineering Contradiction:
Improveconnection stabilityVSAvoidvalve body structure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

Instead of making the entire valve body complex, the snap-fit part introduces a localized feature only where needed for welding ring positioning. This local quality approach maintains overall structural simplicity while providing the necessary stability at the critical connection point

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The snap-fit part may combine different material properties or structural characteristics (such as elastic deformation capability combined with mechanical constraint) to achieve stable positioning without requiring a complex overall structure, resolving the contradiction between stability and simplicity

Inventive Principle:
Principle #40Composite materials

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 snap-fit design improves the connection stability by increasing the contact area and preventing deformation of the welding ring, ensuring a secure and stable joint between the inlet pipe and valve body.

Implementation Method 1

A snap-fit part is formed on either or both of the valve body and the inlet pipe and located at a plug-in position between the inlet pipe and the valve body. The snap-fit part is configured for allowing a welding ring to be snapped into.

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Fastener

Implementation Method 2

When the welding ring is melted, the welding ring expands under stress, causing melted solder to be positioned relatively far from a connection between the inlet pipe and the valve body

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

since each of the annular snap groove and the welding ring has an annular shape, the contact area therebetween can be increased. This results in a superior restraining effect of the annular snap groove on the welding ring.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4696910A1Pilot valve and switching valve
Publication Date: 2026.02.18 ZHEJIANG DUNAN ARTIFICIAL ENVIRONMENT CO LTD
  • EP4696910A1 patent drawingFigure 1~2
  • EP4696910A1 patent drawingFigure 3~4
  • EP4696910A1 patent drawing

AI summary

A pilot valve and a switching valve. The pilot valve includes a valve body (1) and an inlet pipe (2) having an end plugged into the valve body (1). A snap-fit part is formed on either or both of the valve body (1) and the inlet pipe (2) and located at a plug-in position between the inlet pipe (2) and the valve body (1), and the snap-fit part is configured for allowing a welding ring (3) to be snapped into.