Stator Wire Crossover for Insulation Integrity
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Solution Overview
Problem
Conventional stators for electric rotating machines face insulation failures due to the peeling off of insulating layers from joints between electric wires, which interfere with the housing inner surface during assembly.
Innovation Solution
The stator design includes a crossover part in the lead portion of one electric wire that crosses over the axial end face from the radially inside to the outside, positioning the joint closer to the axial end face than the crossover part, preventing interference with the housing and ensuring the insulating layer remains intact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the joint between electric wires is positioned at the coil end part, then the electric wires can be joined together, but the insulating layer may be peeled off when the joint interferes with the housing inner surface
Solution Approach 1:
The patent changes the spatial arrangement by introducing a crossover part that extends in the radial direction, creating a three-dimensional configuration where the joint is positioned axially closer to the stator core while the crossover part occupies radial space. This dimensional repositioning prevents interference with the housing inner surface while maintaining manufacturing feasibility.
Solution Approach 2:
The crossover part is formed in advance during wire preparation, before the joining process. This preliminary formation of the crossover geometry allows the joint to be positioned optimally without requiring post-assembly adjustments, preventing insulating layer peeling from the outset.
2Reliability
If the insulating layer is applied after wire joining, then the joint is insulated, but the insulating layer is weaker and easier to peel off compared to the original insulating coats
Solution Approach 1:
The insulating coats are applied to the electric wires before the joining process, when the wires are still in their original strong state. This preliminary insulation application ensures that the base insulating layer is already in place and can better withstand subsequent processing and operational stresses.
Solution Approach 2:
The original insulating coats serve as a pre-applied protective layer that cushions and protects the wire structure before joining occurs. This beforehand protection ensures that even if the post-joining insulating layer is weaker, the underlying insulating coats provide sufficient insulation strength.
3Object-affected harmful factors
If the joint is positioned closer to the axial end face of the stator core, then interference with the housing is prevented, but the joint position must be precisely controlled
Solution Approach 1:
The crossover part provides a radial dimension buffer that allows the joint to be positioned axially closer to the stator core without causing interference. This radial extension creates spatial separation, reducing the stringency of axial position control requirements while preventing harmful interference.
Solution Approach 2:
The crossover part acts as an intermediary structure between the joint and the housing inner surface. It provides physical separation and prevents direct contact between the joint and the housing, thereby eliminating interference while allowing greater positioning flexibility.
Data Source
AI summary
A stator includes a stator coil formed of electric wires which include a joined pair of first and second electric wires. The first electric wire has a lead portion led out from the radially inner periphery of a first slot of a stator core and including a crossover part. The crossover part crosses over an axial end face of an end part of the stator coil from the radially inside to the radially outside of the axial end face; the end part protrudes from an axial end face of the stator core. The second electric wire has a lead portion led out from the radially outer periphery of a second slot of the stator core. The lead portions of the electric wires are joined together with a joint formed therebetween. The joint is positioned closer to the axial end face of the stator core than the crossover part is.