Motor Rotor Blade Part Cooling Hole Pressure Difference
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Solution Overview
Problem
Conventional motor cooling technologies face inefficiencies due to low pressure differences across the rotor, leading to reduced cooling medium flow rates and insufficient cooling, especially in motors with rare-earth magnets, which experience temperature rises that degrade magnetic forces and increase heat emission.
Innovation Solution
The motor design incorporates a rotor with a rotor core, permanent magnets, and end plates featuring a blade part that creates a pressure difference by acting as a centrifugal fan, increasing the flow rate of the cooling medium through cooling holes and enhancing rotor coolability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cooling medium is fed through a heat transfer member inserted in the rotor shaft direction, then the rotor is cooled down from inside, but the flow rate of the cooling medium decreases when pressure difference between both ends of the rotor is small
Solution Approach 1:
The rotor structure is segmented into multiple functional components: rotor core, end plates, and heat transfer members positioned at both ends. This segmentation allows the cooling medium to be introduced from both ends simultaneously, effectively dividing the cooling flow path and increasing the total flow rate while maintaining efficient heat transfer from the rotor core.
Solution Approach 2:
The cooling approach transitions from a single-directional cooling medium flow (through one end) to a two-directional flow (through both ends of the rotor). By utilizing both ends of the rotor for cooling medium introduction, the system effectively adds a dimensional aspect to the cooling flow path, thereby increasing the total flow rate and cooling capacity.
2Quantity of substance
If the pressure difference between both ends of the rotor is small, then the cooling structure is simple, but the inflow of cooling medium into the heat transfer member decreases
Solution Approach 1:
The cooling structure is divided into independent modules: two end plates with cooling holes, heat transfer members at each end, and a rotor core. This modular segmentation allows each component to perform its specific function independently, increasing cooling medium inflow through distributed entry points while keeping each individual component relatively simple in design.
Solution Approach 2:
The end plates serve multiple functions: they provide structural support for the rotor, act as barriers to contain the cooling medium within the rotor, and serve as entry points for the cooling medium through integrated cooling holes. This multi-functionality increases cooling medium inflow without proportionally increasing overall structural complexity.
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 design significantly increases the rotor's coolability by enhancing the pressure difference and flow rate of the cooling medium, effectively addressing the inefficiencies in conventional cooling methods and maintaining magnetic performance in high-temperature conditions.
Implementation Method 1
when the rotor rotates in a state in which a cooling medium exists in the motor, negative pressure is caused on a part of the first end plate in the vicinity of the rotary shaft by the blade part provided on the first end plate and the pressure difference between both ends of the rotor in a direction of the rotary shaft increases
Data Source
AI summary
A motor comprises a rotor including: a rotor core to rotate on a rotary shaft; a permanent magnet inserted in a magnet insertion hole formed in the rotor core; first and second end plates provided on both end faces of the rotor core respectively in a direction of the rotary shaft; and a blade part provided on a surface of the first end plate to surround the rotary shaft. The rotor includes a cooling hole having an opening between the blade part of the first end plate and the rotary shaft and passing through the rotor core and the second end plate.