Expansion Valve Contact Geometry for Vibration Noise Suppression

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Solution Overview

Problem

Conventional expansion valves experience vibration and noise issues due to the instability of the ball valve at small opening degrees, which complicates assembly and introduces additional components like anti-vibration springs that increase complexity and flow resistance.

Innovation Solution

The expansion valve incorporates a contact structure between the actuating bar and valve body with convex curved surfaces, and an engagement structure between the actuating bar and drive unit with eccentric convex curved surfaces, eliminating the need for anti-vibration springs by applying lateral loads to suppress vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an anti-vibration spring is provided in the actuating bar to suppress valve body vibration, then valve vibration is suppressed, but the number of parts increases and assembly time increases

Engineering Contradiction:
Improvevalve vibration suppressionVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the anti-vibration spring from the system by redesigning the contact surfaces. The convex curved surface on the actuating bar and the corresponding concave curved surface on the valve body create a self-stabilizing mechanism that suppresses vibration without requiring the additional spring component.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of adding a spring to suppress vibration, the invention inverts the approach by using the geometric shape of the contact surfaces themselves to provide stabilization. The convex-concave surface pairing creates inherent stability through its geometry rather than through elastic deformation of a spring.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If an anti-vibration spring is provided to suppress valve body vibration, then valve vibration is suppressed, but assembly work becomes more complicated and manhours increase

Engineering Contradiction:
Improvevalve vibration suppressionVSAvoidassembly work
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention removes the anti-vibration spring from the assembly process. The convex curved surface on the actuating bar and the concave curved surface on the valve body are integrated into the basic components, eliminating the need for separate spring installation steps and reducing assembly complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If an anti-vibration spring is provided in the valve chamber to suppress valve body vibration, then valve body vibration is suppressed, but the structure within the valve chamber becomes complicated and assembly work is complicated

Engineering Contradiction:
Improvevalve body vibration suppressionVSAvoidstructure within valve chamber
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the anti-vibration spring from the valve chamber entirely. By transferring the vibration suppression function to the contact surfaces between the actuating bar and valve body, the valve chamber structure remains simple and free of additional components.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If an anti-vibration spring is provided in the valve chamber, then valve body vibration is suppressed, but the anti-vibration spring becomes a flow resistance for the refrigerant and may itself vibrate causing abnormal noise

Engineering Contradiction:
Improvevalve body vibration suppressionVSAvoidflow resistance and abnormal noise
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention removes the anti-vibration spring from the refrigerant flow path. The vibration suppression function is achieved through the contact surfaces of the actuating bar and valve body, which do not interfere with refrigerant flow and do not generate additional noise.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution effectively reduces valve vibration and noise without additional components, simplifying assembly and minimizing flow resistance, thereby enhancing the operational stability and quietness of the expansion valve.

Implementation Method 1

the actuating bar 21 and the valve body 18 are adapted to come into contact with each other on spherical surfaces... a lateral load is applied to the actuating bar 21... It has been found that the lateral load applied to the actuating bar 21 suppresses a vibration of the valve body 18

Methodology Applied
Scientific EffectLateral load application through convex curved surface contact:

Data Source

PatentEP4080139A1Expansion valve
Publication Date: 2022.10.26 FUJIKOKI CORP
  • EP4080139A1 patent drawingFigure 1
  • EP4080139A1 patent drawingFigure 2~3
  • EP4080139A1 patent drawingFigure 4~5

AI summary

To suppress generation of a valve vibration sound without any another member such as an anti-vibration spring. In an expansion valve including a valve main body (12) having a valve chamber (16) which is communicated with a refrigerant inflow channel (13) and a refrigerant outflow channel (14), a valve body (18) which is arranged within the valve chamber, and changes a flow rate of the refrigerant by moving forward and backward with respect to a valve seat (17), a biasing member (20) which biases the valve body toward the valve seat, an actuating bar (21) which comes into contact with the valve body and moves the valve body in a valve opening direction against a biasing force generated by the biasing member, and a drive unit (24) which drives the actuating bar, the valve body is adapted to include a convex curved surface (for example, a spherical body), a leading end surface (21a) of the actuating bar is formed into a convex curved surface (for example, a spherical surface), and the leading end surface is brought into contact with the convex curved surface of the valve body.