Electric Machine Bell Rotor Bifilar Cooling
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Solution Overview
Problem
Existing electrical machines face challenges in achieving a compact and cost-effective design while ensuring efficient cooling to prevent demagnetization of permanent magnets and overheating of windings, which are critical for reliable operation.
Innovation Solution
The electrical machine incorporates a bifilar helical cooling channel system with a one-piece pot-shaped housing, featuring concentrically arranged outer and inner stators and a bell rotor, allowing for efficient cooling of both stators using a common cooling medium and reducing the risk of demagnetization and overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional cooling system is used for both stators, then the structure becomes complex and manufacturing becomes difficult, but the cooling function is insufficient
Solution Approach 1:
The patent combines the cooling systems for the inner stator and outer stator into a single integrated cooling device. The cooling device includes a cooling medium supply unit that supplies cooling medium to both stators, and a cooling medium discharge unit that discharges cooling medium from both stators, merging multiple cooling functions into one unified structure that reduces complexity while maintaining effective cooling.
Solution Approach 2:
The cooling device is designed as a multi-functional unit that simultaneously cools both the inner stator and outer stator. The cooling channels are configured to provide cooling medium to multiple stators through a single device, making the cooling system universal and eliminating the need for separate cooling systems for each stator.
2Reliability
If high coercive field strength permanent magnets are used, then demagnetization is prevented, but costs increase due to higher rare earth content
Solution Approach 1:
The patent applies preliminary anti-action by implementing a cooling system that prevents temperature rise before demagnetization can occur. The cooling channels are positioned to cool the permanent magnets in advance, preventing the temperature from reaching levels that would cause demagnetization, thereby allowing the use of lower-cost magnets with lower coercive field strength.
Solution Approach 2:
The patent changes the temperature parameter by implementing active cooling of the permanent magnets. By maintaining lower operating temperatures through the cooling medium flow, the magnets operate in a temperature range where lower coercive field strength materials remain stable and resistant to demagnetization.
3Volume of moving object
If compact cooling channels are used, then the machine size is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements cooling channels in the radial direction of the stators, utilizing the radial dimension to create compact cooling paths. The cooling channels extend radially through the stator structure, allowing efficient heat removal in a compact space without requiring excessively precise manufacturing tolerances.
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 design enhances the compactness and reliability of the electrical machine by effectively dissipating heat, enabling the use of lower-cost permanent magnets and preventing damage to windings, thus ensuring efficient operation as a motor or generator.
Implementation Method 1
a first cooling device for cooling the inner stator and a second cooling device for cooling the outer stator, the first cooling device having a helical cooling channel according to the invention
Implementation Method 2
the first cooling device having a helical cooling channel according to the invention, the first cooling device having in particular a bifilar shape
Data Source
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AI summary
The invention relates to an electric machine (1) comprising an outer stator (2), an inner stator (5) arranged concentrically to the outer stator (2) within the outer stator (2), a rotor (13) arranged concentrically to the outer stator (2) and the inner stator (5) between the outer stator (2) and the inner stator (5) and movable relative to the outer stator (2) and the inner stator (5), and a shaft (14) of a first cooling device (29) for cooling the inner stator (5) and a second cooling device (31) for cooling the outer stator (2). The first cooling device (29) has a helical cooling channel (32), wherein the first cooling device (29) in particular has a bifilar shape. In one method, the housing of such an electric machine (1) is produced by 3D printing.