Internal Protector Mounting in Hermetic Compressor Stator

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Solution Overview

Problem

The existing installation method for internal protectors in hermetic electric compressors, which involves tying a mechanical protector to the stator winding wire using a cord, results in high production costs and increased assembly workload due to insufficient ease-of-assembly.

Innovation Solution

The internal protector is latched between the inner and outer circumferential flanges of plastic insulating bobbins fitted around the stator winding wire, using hooks or latching holes and retainer plates, to simplify the installation process and reduce assembly complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the internal protector is tied and fixed with a tying cord to the stator winding wire, then the internal protector can be securely installed, but the production cost increases and assembly workload increases due to insufficient ease-of-assembly

Engineering Contradiction:
Improvesecure installation of internal protectorVSAvoidease-of-assembly
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the internal protector with the insulating bobbin structure by providing a clamping groove on the bobbin that receives and secures the protector. This merging of functions eliminates the need for separate tying cords and complex assembly operations, while maintaining secure installation through the integrated clamping mechanism

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The insulating bobbin acts as an intermediary element that facilitates the secure installation of the internal protector. The bobbin's clamping groove structure serves as a mediator between the protector and the stator winding wire, providing a simple yet effective mounting solution that improves ease-of-assembly while ensuring reliable fixation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the internal protector is tied and fixed with a tying cord to the stator winding wire, then the internal protector can be securely installed, but the production cost increases due to additional materials and assembly steps

Engineering Contradiction:
Improvesecure installation of internal protectorVSAvoidinstallation structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the mounting function into the insulating bobbin structure itself by incorporating a clamping groove. This integration eliminates the need for separate tying cords and complex installation structures, reducing both device complexity and production costs while maintaining secure protector installation

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The insulating bobbin is designed with multi-functionality: it provides electrical insulation, structural support for the stator winding wire, and a mounting mechanism for the internal protector through its clamping groove. This universal design reduces the need for additional components, simplifying the overall installation structure and reducing production costs

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2631483B1Hermetically sealed electric motor compressor
Publication Date: 2020.04.15 MITSUBISHI HEAVY IND THERMAL SYST
  • EP2631483B1 patent drawingFigure 1
  • EP2631483B1 patent drawingFigure 2(A)~2(B)
  • EP2631483B1 patent drawingFigure 3(A)~3(B)

AI summary

An object is to provide a hermetic electric compressor that can simplify the installation structure of an internal protector and improve the ease-of-assembly thereof. In a hermetic electric compressor having a compressor and an electric motor (10) built into a sealed housing (2), the electric motor (10) includes a stator (8) to which plastic insulating bobbins (30) having flanges (30B, 30C) on an inner and outer circumferences of a plurality of tooth parts of a stator core are fitted and around which a stator winding wire (8A) is wound in concentrated winding around the plastic insulating bobbins (30), and an internal protector (29) for electric-motor protection is latched between the inner and outer circumferential flanges (30B, 30C) of the plastic insulating bobbins (30) by being urged against the stator winding wire (8A).