Expansion Valve Vibration-Proof Spring for Stable Shaft Sliding

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Solution Overview

Problem

Existing expansion valves face challenges in preventing vibration of actuating members due to refrigerant pressure fluctuations, leading to noise issues, with existing vibration-proof springs either being too large or having low rigidity, which affects their effectiveness in stabilizing the valve element.

Innovation Solution

A vibration-proof spring with a hollow tube shape and a spring part integrally formed with the side wall, where the spring part is warped to provide sliding friction and sufficient elasticity, allowing the actuating rod to slide stably, while maintaining a compact size by positioning the spring part along or slightly outward from the spring body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the annular section is made larger to accommodate the vibration-proof spring, then the spring can provide sufficient biasing force, but the overall size of the expansion valve increases

Engineering Contradiction:
Improvebiasing forceVSAvoidsize of expansion valve
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The vibration-proof spring is nested inside the actuating rod, with the spring body positioned within the hollow cylindrical section of the actuating rod. This nesting arrangement allows the spring to provide sufficient biasing force while maintaining a compact overall size, as the spring occupies space within the existing actuating rod structure rather than requiring additional external space

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The spring is oriented radially inward, with its biasing force applied in a radial direction rather than axially. This dimensional change allows the spring to exert sufficient force on the actuating rod while maintaining a compact axial length, effectively utilizing the radial dimension to achieve the required force without increasing the overall valve size

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If the wire is bent to form the vibration-proof spring, then the spring can be compact, but the rigidity is low and the spring bends along the axis line

Engineering Contradiction:
Improvesize of springVSAvoidrigidity
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The spring body is formed with a curved or arc-shaped cross-section rather than a simple bent wire configuration. This curved geometry provides inherent rigidity while maintaining a compact form factor, preventing the spring from bending along the axis line under load while still achieving the required compact size

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The spring is constructed using a composite structure combining a rigid outer shell with an elastic inner core, or using a specially formulated elastic alloy that provides both rigidity and flexibility. This composite approach enables the spring to maintain its shape and provide sufficient rigidity while remaining compact in size

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 solution effectively inhibits valve element vibration, providing appropriate sliding friction and sufficient sliding load, thus stabilizing the actuating rod and maintaining a reduced and compact spring size, addressing the limitations of previous designs.

Implementation Method 1

configured to develop a sliding friction by biasing the actuating rod

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the spring part is warped such that the spring part is coplanar with the side wall of the spring body or the spring part is warped outwardly from the spring body and an elastically reactive force resulting from the warped spring part

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2667118B1Expansion valve comprising a vibration-proof spring
Publication Date: 2020.04.01 TGK CO LTD
  • EP2667118B1 patent drawingFigure 1
  • EP2667118B1 patent drawingFigure 2A~2F
  • EP2667118B1 patent drawingFigure 3A~3E

AI summary

An expansion valve (1) according to one embodiment includes a shaft (33) for transmitting the drive force of a drive section (3) to a valve element (18) and a vibration-proof spring (50, 250, 350, 450, 550), set between the body (2) and the shaft (33), which generates the sliding friction by biasing the shaft (33). The vibration-proof spring (50, 250, 350, 450, 550) includes a body (52, 252, 352, 452, 552), of a hollow tube shape (cylindrical shape), inside which the shaft (33) is insertable, a spring part (54, 454, 554), which is integrally formed with a side wall of the body (52, 252, 352, 452, 552) and which is supported by the body (52, 252, 352, 452, 552), and a bulging portion (56, 556) formed on the spring part (54, 454, 554) in a protruding manner such that the tip of the bulging portion (56, 556) is placed opposite to a part of the shaft (33) corresponding to the spring part (54, 454, 554). When the bulging portion (56, 556) abuts against the shaft (33) inserted to the vibration-proof spring (50, 250, 350, 450, 550), the spring part (54, 454, 554) is placed in a position along the body (52, 252, 352, 452, 552) or is warped outwardly from the body (52, 252, 352, 452, 552), so that the elastically reactive force resulting from the warped spring part (54, 454, 554) allows the shaft (33) to slide in a stabilized manner.