Rotary Electric Machine Bearing Cooling With Insulated End Brackets
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Solution Overview
Problem
Existing rotary electric machines face challenges in reducing temperature rises of bearings due to heat transfer from internal air and heat conduction from the rotor core, leading to premature lubrication failure.
Innovation Solution
Incorporating a heat insulating layer in the end brackets of the rotary electric machine to prevent heat transfer from internal air and conduction from the rotor core, combined with an air cooling system that uses external air to cool the bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a fan and ventilation path are added to cool the bearing, then the cooling performance is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the bearing cooling function from the general ventilation system by providing a dedicated cooling air passage that introduces cooling air directly to the bearing location, separate from the coil cooling path. This targeted approach improves bearing cooling efficiency without requiring a separate fan or complex ventilation path modifications.
Solution Approach 2:
The patent introduces a heat insulating layer as an intermediary between the stator core and the bearing support structure. This heat insulating layer blocks heat conduction from the hot stator core to the bearing, effectively reducing bearing temperature without requiring active cooling mechanisms.
2Ease of manufacture
If the bracket does not have a heat insulating layer, then the structure is simple, but the bearing temperature rises due to heat conduction from the stator core
Solution Approach 1:
The patent introduces a heat insulating layer as an intermediary between the stator core and the bearing support structure. This heat insulating layer blocks heat conduction from the hot stator core to the bearing, effectively reducing bearing temperature without requiring active cooling mechanisms.
Solution Approach 2:
The heat insulating layer is applied locally only at the bearing support location within the bracket, rather than insulating the entire bracket structure. This localized approach provides the necessary thermal isolation while minimizing additional complexity and maintaining ease of manufacture.
3Duration of action of stationary object
If cooling air is introduced to cool the bearing, then the lubrication life is extended, but the device complexity increases
Solution Approach 1:
The patent makes the cooling air passage serve multiple functions: it cools the bearing and simultaneously acts as a structural component of the bracket assembly. The cooling air passage is integrated into the bracket structure itself, eliminating the need for separate cooling components and reducing overall device complexity.
Solution Approach 2:
The bearing cooling system utilizes the same cooling air source that cools the coils, making the cooling system self-sufficient. The cooling air is directed through different passages to serve both the coils and the bearing, eliminating the need for separate cooling systems for each component.
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
Effectively reduces temperature rises of bearings, thereby extending the lubrication life and improving cooling performance.
Implementation Method 1
one of the end brackets includes a heat insulating layer on an inner side or an outer side of the machine to prevent heat from flowing into the bearings
Implementation Method 2
various cooling methods are provided for rotary electric machines. As cooling methods for rotary electric machines, there are an open type that takes in cooling air from outside and cools respective parts inside a rotary electric machine
Data Source
AI summary
The present invention provides a rotary electric machine which suppresses a temperature rise of bearings by reducing heat transfer from internal air to the bearings and heat conduction from a rotor core, and improves the lubrication life of the bearings. A rotary electric machine of the present invention comprises a rotor including a shaft; a stator placed facing the rotor with a certain gap (an air gap) therebetween and supported by a stator frame; bearings which sustain the shaft; and end brackets which hold the bearings, wherein one of the end brackets includes a heat insulating layer on an inner side or an outer side of the machine to prevent heat from flowing into the bearings.