Variable Capacity Compressor Check Valve Noise Reduction

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Solution Overview

Problem

Check valves in variable capacity compressors face challenges in minimizing valve noise due to back pressure, as the spool valve does not maintain tight contact with the valve case, leading to increased frictional resistance and vibration.

Innovation Solution

The design includes a valve seat with refrigerant guide recesses and asymmetrically arranged refrigerant discharge holes, where the spool valve is inclined to minimize contact areas and features a third discharge hole positioned higher than the second, ensuring the spool valve tightly contacts the valve case, reducing frictional resistance and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the spool valve is designed to maintain tight contact with the valve case under back pressure, then frictional resistance increases causing valve noise and vibration, but if contact is reduced, then sealing performance deteriorates

Engineering Contradiction:

Improvevalve noiseVSAvoidsealing performance

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The valve case is segmented into multiple functional zones: a sealing surface for tight contact, a friction reduction surface with reduced contact, and discharge holes positioned at different heights. This segmentation allows different portions of the spool valve to have different contact characteristics - tight sealing at one interface while minimizing frictional contact in another zone, thereby reducing noise without compromising sealing performance

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the spool valve and valve case are given different local qualities: the sealing surface maintains high contact pressure for reliable sealing, while the friction reduction surface has reduced contact area and pressure. The asymmetric discharge holes are strategically positioned to manage refrigerant flow locally, creating beneficial pressure distributions that reduce vibration and noise in specific areas without affecting overall sealing

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If the spool valve contacts the valve case to prevent lateral movement, then frictional resistance increases causing noise, but without contact, lateral stability is reduced

Engineering Contradiction:

Improvespool valve stabilityVSAvoidfrictional resistance

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The valve case incorporates asymmetric discharge holes positioned at different heights and locations. This asymmetric configuration creates unbalanced refrigerant pressure forces that actively stabilize the spool valve in its intended position, reducing lateral movement tendencies. The asymmetry allows the valve to maintain stability through fluid pressure rather than relying solely on frictional contact, thereby reducing noise while preserving stability

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The invention utilizes refrigerant pressure forces generated through the asymmetric discharge hole configuration to provide stabilizing effects on the spool valve. The high-pressure refrigerant flow creates pressure differentials that push the valve into stable positions, replacing mechanical friction-based stability with fluid-pressure-based stability, thus reducing frictional resistance and associated noise

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 decreases valve noise by minimizing frictional resistance and preventing spool valve vibration, ensuring stable operation even under varying refrigerant pressures.

Implementation Method 1

an elastic member disposed between the valve case and the spool valve

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a spool valve disposed within the valve case to selectively open and close the refrigerant introduction hole and the first and second refrigerant discharge holes

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS9004099B2Check valve for variable capacity compressor of vehicle

Publication Date: 2015.04.14 LTC CO LTD

AI summary

Disclosed is a check valve for a variable capacity compressor of a vehicle, which includes a valve seat including a refrigerant introduction hole, a valve case disposed above the valve seat, and including refrigerant discharge holes along a circumferential surface of a cylindrical body thereof, a spool valve disposed within the valve case to selectively open and close the refrigerant introduction hole and the refrigerant discharge holes, and an elastic member disposed between the valve case and the spool valve.