Compressor Muffler Cover Sealing for Pressure Pulsation Noise

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Solution Overview

Problem

Existing compressors face challenges in effectively reducing vibration and noise caused by pressure pulsation of compressed refrigerant due to gaps between the muffler cover and the boss portion, leading to insufficient noise reduction.

Innovation Solution

The compressor design includes a muffler cover with conical side surfaces that form sealed contacts with the front head boss portion, utilizing multiple contact points to prevent refrigerant leakage and noise, and symmetric sound sources to suppress vibration and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a clearance is provided between the muffler cover opening and the boss portion, then assembly ease is improved, but vibration and noise reduction effectiveness deteriorates due to refrigerant leakage through the gap

Engineering Contradiction:
Improveassembly easeVSAvoidvibration and noise
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The contact surface on the boss portion is divided into an oblique surface and a perpendicular surface, creating a multi-stage sealing structure. The oblique surface provides initial contact and guidance, while the perpendicular surface ensures tight sealing, preventing refrigerant leakage through the gap between the muffler cover and boss portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the contact interface have different geometric properties optimized for specific functions. The oblique surface area is designed with a specific angle range (15°-45°) to facilitate assembly and initial sealing, while the perpendicular surface provides the primary sealing contact. This local differentiation of geometric quality ensures both easy assembly and effective noise reduction.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If the gap between the muffler cover and boss portion is reduced to prevent refrigerant leakage, then vibration and noise reduction is improved, but assembly difficulty increases

Engineering Contradiction:
Improvevibration and noiseVSAvoidassembly difficulty
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The oblique surface is designed to provide preliminary contact and guidance during the assembly process. This inclined surface allows the muffler cover to be guided onto the boss portion at an angle, preventing misalignment and facilitating easy assembly while ensuring that the perpendicular sealing surface makes proper contact from the beginning.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The contact surfaces utilize angular geometries (oblique and perpendicular surfaces) that create a conical interface. This angular contact geometry provides stable surface contact between the muffler cover and boss portion, ensuring consistent sealing while maintaining ease of assembly through self-alignment properties.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If dimensional tolerances are tight to ensure sealing, then refrigerant leakage prevention is improved, but manufacturing cost and difficulty increase

Engineering Contradiction:
Improvesealing effectivenessVSAvoiddimensional tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The sealing mechanism transitions from relying on tight radial clearance to utilizing surface contact geometry. By changing the contact interface from a simple cylindrical gap to a conical surface contact with specific angle ranges, the design achieves reliable sealing through geometric constraint rather than tight dimensional tolerances, thereby reducing manufacturing difficulty and cost.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The oblique and perpendicular surfaces act as intermediary elements that mediate between the muffler cover and boss portion. These intermediate contact surfaces distribute the sealing function across a larger area with favorable geometry, reducing the impact of dimensional variations and ensuring consistent sealing effectiveness without requiring extremely tight tolerances.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4353973B1compressor
Publication Date: 2026.02.04 DAIKIN INDUSTRIES LTD
  • EP4353973B1 patent drawingFigure 1
  • EP4353973B1 patent drawingFigure 2
  • EP4353973B1 patent drawingFigure 3

AI summary

A compressor is proposed, which suppresses the vibration and noise caused by pressure pulsation of a compressed fluid. The compressor includes a compression mechanism. The compression mechanism includes a front head including a boss portion and a muffler cover attached to the front head. The front head includes a first contact surface that is part of a conical side surface on an outer peripheral surface of the boss portion. The muffler cover includes a first surface having a circular first opening formed therein, into which the boss portion is inserted. A first end portion of the first surface forming the first opening is in contact with the first contact surface in a state where the muffler cover is attached to the front head.