Stator Lamination Pin Press-Fit for Precise Rotor Alignment
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Solution Overview
Problem
Existing methods for aligning stators with rotors in electric machines, such as thermal fit or press fit operations and fastener-based methods, are costly and time-consuming, and there is a need for enhanced methods to ensure proper alignment.
Innovation Solution
A method involving the use of pins pressed into holes of the lamination stack to secure and align the stator within a housing, with the pin being held by a support that ensures proper alignment and reduces the need for precise housing crafting and minimizes misalignment issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal fit or press fit operations are used to align stator with housing, then alignment precision is improved, but manufacturing cost increases
Solution Approach 1:
The pin is pre-installed into the stator lamination stack before final assembly with the housing. This preliminary alignment action ensures that when the stator is subsequently installed in the housing, the alignment is already established, eliminating the need for costly thermal fit or press fit operations to achieve precise alignment.
Solution Approach 2:
The pin serves as an intermediary alignment element between the stator lamination stack and the housing. By installing the pin into the stator first, it acts as a reference feature that guides and constrains the stator's position relative to the housing, simplifying the overall alignment process and reducing manufacturing costs.
2Reliability
If fastener based method is used to secure lamination extensions, then alignment reliability is improved, but production time increases
Solution Approach 1:
The pin is installed into the stator lamination stack during the winding or assembly process, before final housing installation. This preliminary securing action establishes reliable alignment early in the manufacturing sequence, eliminating the need for subsequent fastener operations and reducing overall production time while maintaining alignment reliability.
Solution Approach 2:
The invention extracts the alignment function from the final assembly step and performs it separately during the winding or intermediate assembly process. By taking out the alignment action and completing it earlier with the pin, the need for time-consuming fastener operations in the final assembly is eliminated.
3Reliability
If pin diameter is increased to improve insertion reliability, then buckling resistance is improved, but alignment precision worsens due to increased clearance
Solution Approach 1:
The invention optimizes the pin diameter to a specific range (0.030 to 0.060 inches) that balances two competing requirements: sufficient diameter to resist buckling during press fit insertion, while maintaining small enough diameter relative to the hole size to minimize clearance and achieve precise alignment. This parameter optimization resolves the contradiction between insertion reliability and alignment precision.
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 method ensures precise alignment of the stator with the rotor, reduces the cost and time associated with traditional alignment methods, and enhances the reliability of the pin insertion process by optimizing the pin diameter and lamination hole length ratio.
Implementation Method 1
press fitting the pin into the opening
Data Source
AI summary
A method for securing a stator, including aligning a pin with an opening in a lamination stack, holding the pin with a support, the support having a surface thereof that is located at a distance from the lamination stack of at least 40 percent of a length of the pin that is exposed outside the lamination stack, and press fitting the pin into the opening. An electric machine, including a stator including a lamination stack having a first end and a second end and an ear depending from the stack, the ear including an opening, and a pin disposed, in press fit relationship, with the stator, the pin extending beyond the first and the second ends of the stator.