Motor Stator Cooling Hole Layout for Balanced Coil-End Refrigerant Flow
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Solution Overview
Problem
In motors, the injection velocity of refrigerant through holes in the stator core varies, leading to insufficient cooling at certain positions, particularly the lower holes due to gravity-induced velocity components, which affects the overall cooling efficiency.
Innovation Solution
The motor design includes a first annular member with a plurality of holes of varying sizes, where the smaller holes have a smaller opening area than larger holes, ensuring higher injection velocities at lower holes to compensate for gravity-induced velocity reductions, and medium holes with gradually decreasing areas to adjust cooling effects, thereby ensuring consistent cooling across all holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant is injected through holes of uniform size in the stator core, then the structure is simple and manufacturing is easy, but the injection velocity varies at different positions leading to insufficient cooling at certain holes
Solution Approach 1:
The patent applies local quality by making each hole's opening area correspond to its vertical position in the stator core. Holes at different heights have different opening areas to compensate for gravity-induced velocity variations, ensuring uniform cooling effectiveness across all positions without requiring complex additional components.
2Reliability
If the opening area of lower holes is increased to compensate for gravity-induced velocity reduction, then cooling effectiveness at lower holes improves, but the overall refrigerant flow increases before normal operation
Solution Approach 1:
The patent changes the parameter of hole opening area based on vertical position within the stator core. By systematically adjusting the opening area parameter for each hole according to its height, the design compensates for gravity effects while controlling overall refrigerant flow quantity, preventing excessive flow before normal operation state is reached.
3Reliability
If refrigerant injection velocity is increased through smaller holes, then cooling effectiveness improves, but pressure loss increases
Solution Approach 1:
The patent applies local quality by optimizing each hole's opening area according to its specific vertical position and flow requirements. This localized optimization ensures that pressure loss is minimized at each position while maintaining adequate injection velocity for effective cooling, rather than uniformly increasing velocity across all holes which would cause excessive overall pressure loss.
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 ensures sufficient cooling at all holes, reduces refrigerant flow before the motor reaches normal operation state, and maintains overall cooling balance without increasing pressure, enhancing the motor's operational efficiency.
Implementation Method 1
injection holes at different velocities depending on positions of the injection holes in a vertical direction, pressure gradient of the refrigerant
Implementation Method 2
injection velocities may not be sufficient enough to cool a coil end... The refrigerant injected through a vertically lower hole has a larger velocity component in a direction opposite to the gravity direction
Implementation Method 3
Refrigerant is injected toward a coil end through each of the injection holes
Implementation Method 4
cooling oil... to cool the coil end
Data Source
AI summary
A motor may include a rotor; a stator comprising a stator core and a coil; a housing that houses the rotor and the stator; and a first annular member that provides a seal between a first end face of the stator core in an axial direction of the stator core and an inner wall surface of the housing. The first annular member may include a plurality of first holes through which refrigerant is injected toward a first coil end of the coil protruding from the first end face of the stator core. The plurality of first holes may include a first large hole and a first small hole, and the first small hole may have an opening area smaller than an opening area of the first large hole.