Rotary Electrical Machine Casing With Non-Branching Cooling Passages
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Solution Overview
Problem
Conventional rotary electrical machines, particularly those used in fuel cell vehicles, face significant temperature rise due to internal heat generation and external heat sources like compressed hot air, with existing cooling structures failing to adequately suppress this increase, especially affecting bearings and stators.
Innovation Solution
A rotary electrical machine design featuring a casing with integrated first and second cooling passage portions that extend from inlet to outlet without branching, where the second passage portion within the housing parts acts as a thermal insulation member, dissipating heat from both the outer peripheral side and the bearing side, maintaining stable thermal insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional cooling structure is used that only cools the outer peripheral side of the stator, then the cooling system is simple, but the bearing temperature rises significantly due to lack of cooling on the bearing side
Solution Approach 1:
The cooling structure is segmented into two distinct cooling passages: a first cooling passage for cooling the stator outer peripheral side, and a second cooling passage for cooling the bearing side. This segmentation allows each passage to be optimized for its specific cooling target, effectively reducing bearing temperature while maintaining reasonable structural complexity
Solution Approach 2:
Different cooling strategies are applied to different locations: the first cooling passage provides cooling at the stator outer periphery, while the second cooling passage provides dedicated cooling at the bearing location. This local quality approach ensures that each critical component receives appropriate cooling without over-cooling other areas
2Temperature
If a cooling passage branches off in the middle, then multiple areas can be cooled simultaneously, but the cooling medium flow rate becomes unstable and thermal insulation properties deteriorate
Solution Approach 1:
The cooling passages are designed to extend continuously from the inlet to the outlet without branching, ensuring that the cooling medium flows through the entire passage length before discharge. This preliminary action of establishing continuous flow paths maintains stable flow rates and consistent thermal insulation properties throughout the cooling process
3Power
If the housing parts are exposed to hot compressed air, then the compressor can achieve high compression ratio, but the housing parts and internal components overheat
Solution Approach 1:
The second cooling passage acts as an intermediary cooling path that intercepts heat from the housing parts before it can transfer to internal components. The cooling medium flows through this passage to absorb heat from the housing parts that are exposed to hot compressed air, thereby maintaining the compression function while preventing overheating of internal components
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 temperature rise by maintaining consistent cooling medium flow rates, ensuring high thermal insulation and heat dissipation performance, thereby preventing overheating of the rotor, stator, and bearings, and extending their lifespan.
Implementation Method 1
a cooling structure that releases the heat generated by power supply to the outside
Implementation Method 2
making water flow through the water-cooling jacket
Data Source
AI summary
Provided is a technology that can sufficiently suppress the temperature rise of a rotary electrical machine. A rotary electrical machine includes a main body part 10 including a rotator and a stator, and a casing part 20 that houses the main body part 10. The casing part 20 includes a first housing part 5 that surrounds the main body part 10 from a peripheral direction, and a second housing part 6 that houses a bearing for rotatably supporting a rotating shaft 2. The casing part 20 is formed with a cooling passage R extending from an inlet Rs for cooling medium to an outlet Re for cooling medium and not branching off in the middle. The cooling passage R includes a first cooling passage portion R1 that passes through the inside of the first housing part 5 and a second cooling passage portion R2 that passes through the inside of the second housing part 6.