Molded Motor Metal Cover for Bearing Corrosion and Fire Containment

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Solution Overview

Problem

Existing mold motors face issues with electrolytic corrosion in bearings and fire risk due to excessive current flow through the coil, requiring complex configurations with multiple connection members and fire protection measures.

Innovation Solution

A mold motor design that uses a metal cover to cover the coil ends and insulators, with a conductive member connecting metal brackets to suppress electrolytic corrosion and prevent fire leakage, utilizing a simple configuration with a metal cover and conductive member to equalize potentials and block fire or smoke.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fire protection measures with inner and outer metallic covers are used, then fire leakage is prevented, but device complexity increases

Engineering Contradiction:
Improvefire protectionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the fire protection function and electrolytic corrosion prevention function into a single metal cover structure. The metal cover serves dual purposes: it acts as a fire barrier to prevent fire leakage from the coil area, and simultaneously serves as the conductive member to equalize potentials and prevent electrolytic corrosion of bearings. This merging of functions reduces the number of components from the conventional inner and outer metallic covers to a single integrated metal cover.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The metal cover is designed as a multi-functional component that simultaneously provides fire protection and electrolytic corrosion prevention. By making the metal cover serve multiple functions, the patent eliminates the need for separate fire protection structures and separate conductive connection structures, thereby simplifying the overall device configuration while maintaining both fire safety and bearing protection.

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

2Reliability

If multiple connection members and complex processing devices are used to connect metal brackets, then electrolytic corrosion is suppressed, but device complexity increases

Engineering Contradiction:
Improveelectrolytic corrosion preventionVSAvoidconnection structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the metal cover with the conductive member function, so that the metal cover itself serves as the conductive path for equalizing potentials between the first metal bracket and the second metal bracket. This eliminates the need for separate connection members such as conduction pins or electric wires that would otherwise be required to prevent electrolytic corrosion.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The metal cover is designed to simultaneously provide structural support, fire protection, and electrical conduction for electrolytic corrosion prevention. This multi-functionality eliminates the need for additional dedicated connection members and processing devices, thereby simplifying both the device structure and the manufacturing process.

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

3Reliability

If conventional fire protection measures with inner and outer metallic covers are used, then fire leakage is prevented, but manufacturing complexity increases

Engineering Contradiction:
Improvefire protectionVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the fire protection function and electrolytic corrosion prevention function into a single metal cover structure. The metal cover serves dual purposes: it acts as a fire barrier to prevent fire leakage from the coil area, and simultaneously serves as the conductive member to equalize potentials and prevent electrolytic corrosion of bearings. This merging of functions reduces the number of components from the conventional inner and outer metallic covers to a single integrated metal cover.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The metal cover is designed as a multi-functional component that simultaneously provides fire protection and electrolytic corrosion prevention. By making the metal cover serve multiple functions, the patent eliminates the need for separate fire protection structures and separate conductive connection structures, thereby simplifying the overall device configuration while maintaining both fire safety and bearing protection.

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

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

The design effectively suppresses electrolytic corrosion and prevents fire leakage with a simplified structure, enhancing motor reliability and longevity by equalizing bearing potentials and blocking external fire and smoke.

Implementation Method 1

a mold motor provided with fire protection measures for preventing leakage of fire to the outside of the motor even if an excessive current flows through a coil in a stator while preventing electrolytic corrosion of a bearing

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4002651B1Molded motor
Publication Date: 2025.12.17 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP4002651B1 patent drawingFigure 1
  • EP4002651B1 patent drawingFigure 2
  • EP4002651B1 patent drawingFigure 3

AI summary

The mold motor includes a rotor, a stator, a pair of bearings, a pair of metal brackets, a mold resin portion, and a metal cover. The mold motor further includes a conductive member. The rotor includes a rotating body fixed to a rotating shaft. The stator faces the rotor, and includes a stator core having a plurality of salient poles and a plurality of coils respectively wound around the salient poles of the stator core via insulators. The pair of bearings are respectively fixed to the pair of metal brackets, and rotatably support the rotor. The mold resin covers the stator. The conductive member electrically connects a first metal bracket among the pair of metal brackets with the metal cover. The pair of metal brackets are electrically connected via the metal cover and the conductive member.