Overmolded Compressor Cylinder Head Sealing

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Solution Overview

Problem

Hermetic compressors in refrigerators face efficiency and performance issues due to deformation of the plastic cylinder head under high temperature, leading to gaps between the cylinder head and valve table, causing refrigerant and heat leakage.

Innovation Solution

The compressor employs an overmolding method to integrate the plastic cylinder head with the metal valve table, ensuring complete contact and preventing separation, along with additional features like flanges and suction mufflers to enhance leak-proofing and assembly ease.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the cylinder head is produced from plastic material, then manufacturing cost and ease of manufacture are improved, but the cylinder head deforms under high temperature causing gaps and refrigerant leakage

Engineering Contradiction:
Improveease of manufactureVSAvoidsealing reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent merges the cylinder head and valve table into a single integrated component produced by injection molding. The valve table is formed as an integral part of the cylinder head, eliminating the gap that would exist between separate components. This integration ensures reliable sealing while maintaining the manufacturing advantages of plastic injection molding.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs composite construction by embedding a metal framework (aluminum or copper alloy) within the plastic cylinder head. This metal reinforcement provides thermal stability and structural strength to prevent deformation under high temperature conditions, while the plastic material maintains ease of manufacture and cost-effectiveness.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If the cylinder head is fixed on the valve table by screwing, then assembly is simplified, but gaps occur between the components allowing refrigerant and heat passage

Engineering Contradiction:
Improveease of assemblyVSAvoidheat loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The cylinder head and valve table are merged into a single injection-molded component, eliminating the need for separate assembly operations like screwing. This integration ensures complete contact between surfaces and prevents gaps, thereby preventing heat loss and refrigerant leakage while maintaining ease of manufacture.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If the cylinder head is produced as a separate component, then manufacturing flexibility is improved, but assembly complexity and potential for gaps increase

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidassembly complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cylinder head and valve table are combined into a single integrated component produced through injection molding. This merger eliminates assembly complexity and potential gaps while maintaining manufacturing flexibility through the versatility of injection molding processes. The integrated design allows for easy production of different configurations by modifying the mold.

Inventive Principle:
Principle #5Merging (Combining)

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 integration prevents refrigerant and heat leakage, improves compressor efficiency, and simplifies assembly by eliminating gaps between the cylinder head and valve table, while also reducing noise through the suction muffler.

Implementation Method 1

the cylinder head is formed on the valve table by overmolding method. The valve table is placed into the mould after being produced. Plastic is injected over the valve table placed into the mould and the cylinder head is produced on the valve table

Methodology Applied
Scientific EffectOvermolding:

Implementation Method 2

at least one suction muffler, having a hollow, closed volume which provides attenuation of the noise generated during pumping of the refrigerant fluid

Methodology Applied
Scientific EffectSound attenuation: Acoustic Absorption

Data Source

PatentEP2859236B1A compressor comprising a cylinder head
Publication Date: 2018.08.08 ARCELIK AS
  • EP2859236B1 patent drawingFigure 1
  • EP2859236B1 patent drawingFigure 2~3
  • EP2859236B1 patent drawingFigure 4

AI summary

A compressor (1) comprising: a casing (2) carrying the components therein, a cylinder (3) wherein the compression process is performed, a cylinder head (4) disposed on the cylinder (3), and a valve plate (5) situated between the cylinder (3) and the cylinder head (4). The cylinder head (3) is formed on the valve plate (5) by overmolding method, thereby forming a single piece.