Resolver Rotor Crimping via Shaft Segmentation
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Solution Overview
Problem
Existing methods for fixing a resolver rotor to a motor rotor, such as crimping or using resilient rings, can affect the detection accuracy of the resolver due to deformation of metal parts or increased component count, leading to higher costs and potential errors in electrical signals.
Innovation Solution
A motor rotor design with a shaft featuring a first and second stepped portion and a recess, where the shaft is crimped to form a crimping protrusion that presses the resolver rotor, minimizing radial expansion and using a manufacturing method that avoids additional components, allowing for low-cost crimping without compromising detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the shaft is crimped using conventional methods, then the resolver rotor is fixed to the shaft, but the metal flow causes radial expansion deforming the resolver rotor and reducing detection accuracy
Solution Approach 1:
The shaft is divided into multiple crimping portions (first, second, third crimping portions) positioned at different angular locations. This segmentation distributes the crimping force across multiple discrete points rather than applying continuous radial pressure, thereby fixing the resolver rotor securely while minimizing overall radial expansion and deformation of the resolver rotor structure.
Solution Approach 2:
The crimping operation is applied locally at specific discrete portions of the shaft rather than uniformly around the entire circumference. Each crimping portion creates localized deformation that provides strong fixing at that specific location while leaving other areas of the resolver rotor unaffected, thus maintaining detection accuracy in non-crimped regions.
2Manufacturing precision
If additional components such as resilient rings or pressing rings are used to fix the resolver rotor, then detection accuracy is maintained, but the number of components and manufacturing complexity increase
Solution Approach 1:
The fixing function is merged into the shaft itself by forming crimping portions directly on the shaft structure. The shaft simultaneously serves as both the rotating component and the fixing mechanism, eliminating the need for separate resilient rings, pressing rings, or other auxiliary fixing components. This integration maintains detection accuracy through precise crimping while significantly reducing component count and assembly complexity.
Solution Approach 2:
The shaft is designed to perform multiple functions: it serves as the rotating shaft, the structural support, and the fixing mechanism through its crimping portions. This multi-functionality eliminates the need for dedicated fixing components, reducing overall device complexity while maintaining the precision required for accurate resolver detection.
3Ease of manufacture
If the shaft is crimped to fix the resolver rotor, then assembly is simplified, but deformation of metal parts may cause errors in electrical signals
Solution Approach 1:
The crimping is segmented into discrete portions rather than continuous deformation. This segmentation allows the shaft to be formed with multiple localized crimping features that provide reliable fixing while distributing the deformation stress, thereby maintaining the structural integrity and electrical signal accuracy of the resolver rotor.
Solution Approach 2:
Deformation is applied locally at specific crimping portions rather than uniformly across the entire shaft-resolver interface. This localized approach ensures reliable mechanical fixing at crimped points while preserving the geometric precision and electrical signal quality in non-crimped regions of the resolver rotor.
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 reduces the risk of deformation-related errors in resolver detection accuracy and lowers production costs by minimizing metal flow and component count, while maintaining effective crimping of the resolver rotor to the shaft.
Implementation Method 1
a first stepped portion to be deformed by a punch abutting thereon during crimping... when the shaft is crimped to the resolver rotor, the first stepped portion of the shaft is buckled in a middle of a recess by a punch, forming a crimping protrusion deformed and protruding from the first stepped portion
Data Source
AI summary
A motor rotor and a method for manufacturing a motor rotor, enabling crimping of the resolver rotor at low cost with less influence on the detection accuracy. A motor rotor includes a resolver rotor and a rotor shaft to which the resolver rotor is affixed by crimping. The rotor shaft includes a first stepped section with which a crimping punch makes contact to deform the first stepped section, a second stepped section with which an end surface of the resolver rotor makes contact, and a cutout groove formed in a surface which is located near the first stepped section and with which an inner peripheral hole section of the resolver rotor makes contact. In the crimping operation, the first stepped section of the rotor shaft is bent within the cutout groove to form a crimping protrusion which presses the end surface of the resolver rotor.