Conical Rotor Cooling Ducts for Electric Machine Heat Dissipation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric vehicle traction motors face significant heating issues, leading to performance limitations, and traditional liquid cooling methods using water or transmission oil are inefficient due to complex sealing requirements and rapid oil degradation at high temperatures.
Innovation Solution
An electric machine with a conically configured cooling duct system within the rotor shaft allows for effective coolant flow and circulation, using transmission oil as a coolant without the need for complex sealing, thereby preventing oil degradation and enhancing heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water is used as coolant and pumped through the rotor shaft under pressure, then cooling efficiency is improved, but sealing complexity increases and power loss increases
Solution Approach 1:
The patent replaces the mechanical pumping system with a passive convection-based cooling system. The conical cooling ducts utilize natural convection currents generated by temperature differences to circulate coolant, eliminating the need for mechanical pumps and complex sealing arrangements while maintaining effective cooling.
Solution Approach 2:
The cooling system is designed to be self-regulating through natural convection. The conical duct geometry automatically generates circulation currents as coolant is heated by the rotor, causing it to rise and flow back without external intervention, making the system self-service and eliminating complex control mechanisms.
2Device complexity
If transmission oil is used as coolant, then sealing complexity is reduced, but oil degradation accelerates at high temperatures
Solution Approach 1:
The patent modifies the thermal parameters within the cooling system by using conical ducts that create more efficient heat distribution and lower peak temperatures. This parameter change reduces the thermal stress on the transmission oil, slowing degradation while maintaining the sealing advantages of oil-based cooling.
Solution Approach 2:
The conical cooling ducts create localized cooling zones with optimized temperature distribution. By shaping the ducts to converge toward the rotor center, the system achieves more uniform heat extraction, preventing localized overheating that would accelerate oil degradation.
3Ease of manufacture
If conventional cylindrical cooling ducts are used, then manufacturing is simpler, but coolant circulation is insufficient
Solution Approach 1:
The patent employs asymmetric conical duct geometry instead of symmetric cylindrical ducts. The conical shape creates asymmetric flow paths that enhance natural convection currents, improving coolant circulation efficiency while remaining manufacturable through standard machining processes.
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 conical cooling duct system actively conveys coolant, effectively discharging heat and preventing oil degradation, allowing for reliable and efficient cooling of the electric machine, reducing power loss, and extending maintenance intervals.
Implementation Method 1
the cooling duct is configured so as to run conically at least in sections in the longitudinal direction of the rotor shaft, with the result that the coolant can be conveyed in the direction of an increasing duct diameter by way of a rotational movement of the rotor shaft
Data Source
AI summary
An electric machine, in particular for an electric vehicle. The machine includes a rotor which can be rotated with respect to a stator and has at least one rotor shaft. The machine includes a duct system for cooling the machine, through which duct system a coolant can flow. The duct system runs at least in sections within the rotor shaft. Here, the duct system includes a cooling duct. The cooling duct is configured so as to run conically at least in sections in the longitudinal direction of the rotor shaft, such that the coolant can be conveyed in the direction of an increasing duct diameter by way of a rotational movement of the rotor shaft.