Motor Cooling Structure Using Rotating Cryogenic Refrigerant Flow
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Solution Overview
Problem
Electric motors in vehicles generate significant heat due to electrical resistance, which can lead to reduced efficiency and potential damage, and existing cooling methods may not adequately address this issue, especially in compact designs requiring high power density.
Innovation Solution
A motor cooling structure that incorporates a rotating pipe through which a cryogenic refrigerant, such as liquid hydrogen or nitrogen, flows to cool the coil, enhancing cooling efficiency and reducing motor size by utilizing the refrigerant's low temperature and centrifugal spray mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional cooling method is used for the motor coil, then the motor structure remains simple, but the cooling efficiency is insufficient and the motor size cannot be reduced
Solution Approach 1:
The patent uses a refrigerant fluid flowing through a cooling pipe to cool the coil, applying hydraulic cooling principles. The refrigerant circulates through the pipe inserted into the shaft, absorbing heat from the coil directly, which significantly improves cooling efficiency compared to conventional air cooling methods.
Solution Approach 2:
The cooling pipe is inserted into the shaft, and the shaft rotates with the rotor. This nested structure allows the cooling system to be integrated within the existing motor components without increasing overall size, while still achieving effective cooling of the coil.
2Productivity
If the motor is designed for high power density with compact size, then the motor becomes more efficient, but heat dissipation becomes more difficult
Solution Approach 1:
The hydraulic cooling system with refrigerant circulation provides high-heat-flux removal capability, enabling the motor to maintain high power density while effectively dissipating the increased heat generation from compact, high-power design.
Solution Approach 2:
The rotating shaft itself serves as the cooling medium delivery system. The shaft rotates integrally with the rotor and carries the cooling pipe, eliminating the need for separate cooling mechanisms and allowing the motor structure to serve its own cooling needs.
3Ease of operation
If a separate pressure pump is added to the cooling system, then the refrigerant flow can be controlled, but the device complexity increases
Solution Approach 1:
The system uses the rotational motion of the motor shaft itself to drive the refrigerant circulation. The shaft rotation provides centrifugal force and pressure differential that naturally circulates the refrigerant through the cooling pipe, eliminating the need for an external pressure pump and reducing system complexity.
Solution Approach 2:
The cooling system transitions from a static pump-driven flow to a dynamic rotation-driven flow. The refrigerant circulation is coupled with the motor operation, where the rotating shaft automatically generates the necessary flow dynamics during motor operation.
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 proposed cooling structure effectively reduces heat generation, improves motor efficiency, and allows for a more compact design with increased power density, ensuring stable and continuous operation without the need for a separate pressure pump.
Implementation Method 1
a pipe which may be at least partially inserted into the shaft and through which a refrigerant for cooling the coil may flow
Implementation Method 2
utilizing the refrigerant's low temperature and centrifugal spray mechanism
Data Source
AI summary
A motor may include a stator with a coil disposed on an inner side thereof, a rotor at least partially surrounded by the coil and having an accommodation space in which a refrigerant for cooling the coil may be accommodated, a shaft connected to the rotor to rotate integrally with the rotor, and a pipe communicating with the accommodation space so that the refrigerant may be introduced from an external source and the refrigerant flows into the accommodation space therethrough.