Motor Cooling Structure with Equal-Length Oil Passages
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Solution Overview
Problem
The existing motor cooling circuits experience non-uniform oil flow rates due to varying distances from the inlet to radial oil passages, leading to increased cooling variations and performance degradation of the motor.
Innovation Solution
A motor cooling structure with a cooling medium supply passage extending axially through the shaft and branching into multiple passages that eject oil uniformly from both ends of the rotor core, ensuring equal distances from the inlet to each ejection hole, thereby equalizing pressure losses and flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cooling medium supply passage extends axially through the shaft and branches into multiple passages, then uniform cooling is achieved, but the device complexity increases
Solution Approach 1:
The cooling medium supply passage is segmented into multiple independent cooling passages (first cooling passage, second cooling passage, third cooling passage) that are distributed symmetrically around the shaft. Each passage independently supplies cooling medium to different regions, ensuring uniform cooling distribution while maintaining manageable structural complexity through modular design
Solution Approach 2:
The patent employs symmetric arrangement of cooling passages around the shaft axis, where passages are positioned at equal angular intervals (e.g., 90 degrees apart). This symmetric configuration ensures that all cooling passages have equal lengths from the inlet to their respective ejection holes, achieving uniform cooling without requiring complex asymmetric adjustments
2Temperature
If multiple cooling passages are used to cool different regions, then cooling coverage is improved, but the flow rate distribution becomes non-uniform
Solution Approach 1:
All cooling passages are designed with equal lengths from the common inlet to their respective ejection holes, creating equipotential flow conditions. The symmetric arrangement ensures that pressure losses are equalized across all passages, resulting in uniform flow rate distribution and preventing any single passage from dominating the flow
Solution Approach 2:
Each cooling passage is specifically configured with identical dimensions and routing characteristics tailored to its position, ensuring that local flow conditions are optimized for uniform distribution. The passages are designed with equal cross-sectional areas and equal lengths, guaranteeing that each region receives an equal share of the cooling medium
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 configuration effectively suppresses cooling variations across the motor components, reducing local heating and performance degradation, and optimizes energy consumption by maintaining consistent oil flow rates.
Implementation Method 1
a cooling medium supply passage that extends to an inside of the shaft in an axial direction of the shaft and passes the cooling medium through the cooling medium supply passage
Implementation Method 2
a plurality of cooling medium passages that are branched from the cooling medium supply passage to cool the rotor core while flowing the cooling medium
Implementation Method 3
generates heat by Joule heating of a coil included in a stator, an eddy current loss and a hysteresis loss generated in a rotor core
Implementation Method 4
generates heat by Joule heating of a coil included in a stator, an eddy current loss and a hysteresis loss generated in a rotor core
Implementation Method 5
generates heat by Joule heating of a coil included in a stator, an eddy current loss and a hysteresis loss generated in a rotor core
Data Source
AI summary
A motor cooling structure for cooling a motor, which includes a shaft transmitting power and a rotor core attached to an outside of the shaft, by a cooling medium, includes: a cooling medium supply passage that extends to an inside of the shaft in an axial direction of the shaft and passes the cooling medium through the cooling medium supply passage; and a plurality of cooling medium passages that are branched from the cooling medium supply passage to cool the rotor core while flowing the cooling medium without branching the cooling medium in the axial direction and then eject the cooling medium from a plurality of ejection holes opened to a surface of the rotor core, wherein distances from a cooling medium inlet, through which the cooling medium flows into the cooling medium supply passage, to the respective ejection holes are equal between the plurality of cooling medium passages.