Skewed Lamination Pack with Bent Conductor Bar Locking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electromagnetic machine rotors face challenges in minimizing magnetic locking and cogging, leading to inefficiencies and noise during operation, particularly due to inertial forces on conductor bars and shorting elements.
Innovation Solution
A method of forming a lamination pack by inserting conductor bars into a lamination stack, skewing the stack, and applying a retaining force to compress the laminations, followed by bending the bar ends to create a locking angle, which prevents axial and radial movement and enhances vibration resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conductor bars are inserted into rotor slots and skewing is applied to reduce magnetic locking and cogging, then magnetic locking and cogging are reduced, but the conductor bars are subject to inertial forces that cause axial and radial movement during operation
Solution Approach 1:
The bar ends are bent at a locking angle greater than the skew angle before operation to pre-establish the locking configuration. This preliminary action ensures that when inertial forces occur during operation, the bars are already constrained by the bent ends exerting compressive axial locking force, preventing axial and radial movement while maintaining the skewing configuration that reduces magnetic locking and cogging
Solution Approach 2:
The bent bar ends act as an intermediary locking mechanism between the conductor bars and the lamination stack. The bar ends are bent to a locking angle to create a mechanical interference fit that mediates the forces between the inertial loads and the lamination stack, preventing movement while allowing the skewing to maintain its beneficial electromagnetic properties
2Productivity
If the lamination stack is compressed to maintain density and packing ratio, then power density consistency is improved, but the complexity of the manufacturing process increases due to the multi-step forming method
Solution Approach 1:
The method merges multiple functions into a single integrated forming process. The retaining force application and bar end bending are combined in one operation, and the skewing is performed as part of the same process sequence. This integration achieves compression, locking, and skewing in a unified manufacturing step, reducing overall process complexity while maintaining density and power density consistency
Solution Approach 2:
The bent bar ends serve themselves as both the locking mechanism and the compression force source. When the bar ends are bent to the locking angle, they automatically exert compressive axial locking force on the lamination stack, maintaining density without requiring separate compression devices or ongoing adjustment mechanisms, thereby simplifying the manufacturing process
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 solution effectively reduces magnetic locking and cogging, maintains power density, and resists high-frequency vibrations, ensuring consistent performance and reduced noise in electromagnetic machines.
Implementation Method 1
the bent bar ends exert a compressive axial locking force on the lamination stack such that the lamination pack resists high frequency vibration
Implementation Method 2
The conductor bars are skewed relative to the axis along the periphery to reduce magnetic locking or cogging between the stator and rotor
Implementation Method 3
the lamination pack resists high frequency vibration of the conductor bars in the stack during operation of the rotor in a motor
Data Source
AI summary
A lamination pack for a motor and method of forming the lamination pack is provided. The method includes inserting a plurality of conductor bars into a plurality of rotor slots defined by a lamination stack such that opposing bar ends of the conductor bars extend from opposing end faces of the lamination stack, skewing the lamination stack and the conductor bars to a skew angle relative to a rotation axis of the lamination stack, and subsequently bending the bar ends of the conductor bars in opposing radial directions to a locking angle greater than the skew angle, to lock each of the conductor bars in its respective rotor slot. The bent bar ends exert a compressive axial locking force on the lamination stack to prevent axial and radial movement of the laminations in the lamination stack and to prevent axial movement of the conductor bars relative to the lamination stack.