Rotor Shaft Heat Sink Insert for Motor Cooling Flow Control
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Solution Overview
Problem
Existing electric motor designs face challenges in effectively cooling the rotor shaft, which can lead to overheating and reduced efficiency.
Innovation Solution
Incorporating a heat sink insert into the rotor shaft with a first flow passage and multiple second flow passages, along with optional flow interruption grooves, to enhance coolant circulation and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple hollow rotor shaft design is used, then the device complexity is reduced, but the cooling efficiency deteriorates leading to overheating
Solution Approach 1:
The rotor shaft is segmented into multiple functional zones with different cooling mechanisms: a central first flow passage for primary coolant flow, multiple radial second flow passages for secondary cooling, and flow interruption grooves for flow distribution. This segmentation allows each zone to address specific cooling needs, improving overall thermal management without excessive complexity.
Solution Approach 2:
Different regions of the rotor shaft are equipped with tailored cooling features: the first flow passage provides axial cooling at the core, while second flow passages provide radial cooling at the periphery. Flow interruption grooves create localized turbulence zones that enhance heat transfer where needed. This local differentiation optimizes cooling efficiency for each thermal hotspot.
2Temperature
If coolant flow is increased to improve cooling efficiency, then temperature control improves, but fluid flow patterns become laminar reducing heat transfer
Solution Approach 1:
Flow interruption grooves are strategically placed to create controlled turbulence and flow disruption in the coolant streams. This mechanical disturbance breaks up laminar flow patterns, enhancing convective heat transfer coefficients. The grooves act as passive turbulence generators that maintain effective heat transfer without requiring additional energy input or complex active control systems.
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
Improves cooling efficiency by breaking up laminar flow and increasing heat transfer, thereby maintaining motor performance and reducing the risk of overheating.
Implementation Method 1
a coolant fluid is pumped into the inlet end of the feed tube as the hollow shaft rotates. Fluid that exits the outlet end of the feed tube flows between the feed tube and the inside circumferential surface of the hollow shaft
Implementation Method 2
The support member causes the coolant fluid to flow circumferentially about the feed tube as the coolant fluid travels in an axial direction back toward the inlet end of the feed tube
Implementation Method 3
The flow interruption groove is formed through the outer insert surface and intersects at least a portion of the second flow passages... breaking up laminar flow and increasing heat transfer
Data Source
AI summary
A motor drive system has a rotor assembly that is rotatable about an axis and includes a hollow shaft, a tube, and one or more fin sets. The tube is received in the shaft and defines a first passage. The fin sets are disposed about the tube and are engaged to the shaft. Each fin set defines a plurality of circumferentially spaced apart fins that are coupled to the shaft and the tube. The first passage is configured to discharge fluid communicated therethrough into a return chamber that is formed in the rotor assembly. A plurality of second passages are formed between the shaft and fins and are in fluid communication with the return chamber.