Electric Motor Can Structure for Asymmetric Pressure Deformation
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Solution Overview
Problem
The challenge in electric motor design is to increase power density while minimizing heat generation, magnetic losses, and material costs, while maintaining structural stability and efficiency, particularly in the context of liquid cooling systems where asymmetric loads and deformations affect the can's performance.
Innovation Solution
The introduction of asymmetric design elements, such as non-uniform fiber reinforcement and eccentric O-ring positioning, allows for advanced deformation simulation and production techniques to optimize the can's structure, reducing air gap size and magnetic losses, and enhancing buckling stability and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the can wall thickness is increased to improve buckling stability, then the buckling resistance improves, but the magnetic losses increase and efficiency decreases
Solution Approach 1:
The patent applies composite material construction for the can, combining materials with different properties to achieve both mechanical strength and electrical insulation. The composite structure provides high buckling resistance while maintaining thin wall thickness, thereby preventing excessive magnetic losses.
Solution Approach 2:
The patent implements local reinforcement strategies where the can wall thickness or material properties are varied in specific regions subjected to highest external pressure, rather than uniformly increasing thickness throughout. This localized approach maintains overall thin-wall design while providing targeted buckling resistance where needed.
2Stability of the object's composition
If the can wall thickness is increased to improve dimensional stability under external pressure, then the deformation resistance improves, but the magnetic losses increase
Solution Approach 1:
Composite material construction enables the can to maintain dimensional stability under hydrostatic pressure without requiring increased wall thickness. The composite structure's high strength-to-weight ratio allows thin walls that resist deformation while minimizing magnetic losses.
Solution Approach 2:
The patent employs local quality enhancement by reinforcing specific regions of the can where external pressure is highest, allowing the majority of the can structure to remain thin and electrically insulating, thus reducing overall magnetic losses while maintaining dimensional stability.
3Loss of energy
If the can is made thinner to reduce magnetic losses, then the efficiency improves, but the buckling stability decreases
Solution Approach 1:
The composite material construction provides high mechanical strength in a thin-walled structure, enabling the can to resist buckling under external pressure while maintaining minimal wall thickness. This resolves the contradiction by achieving both thin walls (low magnetic losses) and high buckling stability through material properties rather than geometry.
4Stability of the object's composition
If expensive ultrahigh-modulus carbon fibers are used to reduce air gap thickness, then the buckling stability improves, but the material costs become prohibitive
Solution Approach 1:
The patent applies local quality enhancement by using expensive ultrahigh-modulus carbon fibers only in specific regions of the can where buckling stress is highest, rather than throughout the entire structure. This localized reinforcement achieves the required buckling stability while significantly reducing material costs compared to uniform use of expensive fibers.
Solution Approach 2:
The can structure is segmented into different material zones, with expensive high-performance fibers concentrated in critical load-bearing regions and cheaper materials used in less stressed areas. This segmentation strategy maintains structural integrity while optimizing cost-effectiveness.
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 approach enables cost-effective, mass-producible cans with improved power density and reduced electrical losses, maintaining structural integrity and efficiency by accounting for asymmetric loads and deformations, thus prolonging the thermal service life and reducing material costs.
Implementation Method 1
Even better cooling of the critical stator windings can be achieved however with a can construction, in which a cooling liquid circulates on the inner side of the coils
Implementation Method 2
the circulating cooling liquid causes the load of an external pressure to act on the can. The compressive load deforms the can. The reason for the uneven pressure distribution is the hydrostatic liquid pressure
Implementation Method 3
loaded regions of the can are identified and their likely deformation with respect to the symmetrically formed can during operation can be calculated in advance, and at least one asymmetric design element counteracting this deformation is provided on the can
Implementation Method 4
To avoid frictional losses of the rotor in the liquid, it is essential to place in the air gap a so-called can, which separates the liquid from the rotor region
Implementation Method 5
The sealing region of the can in the air gap comprises a groove, which runs around the rotor region and in which the so-called O-rings are fitted, for the mounting and sealing of the can
Data Source
AI summary
Various embodiments of the teachings herein include a can for an electric rotating machine. An example can includes: a bearing seat; and an asymmetric element on the can and/or on the bearing seat. The asymmetric element counteracts an expected deformation in loaded regions of the can, the expected deformation identified by measurement data and/or deformation simulation calculated in advance.