Electric Motor Stator Insulation via Plastic Extrusion Coating
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Solution Overview
Problem
Electric motors with plastic bearing seats tend to oscillate, leading to undesirable noise and requiring complex manufacturing processes, while also lacking effective electrical insulation and grounding connections.
Innovation Solution
A laminated stator core and metallic stator bushing are partially or fully surrounded by a plastic extrusion coating, forming a common insulation sheath that encapsulates the unit, reducing noise and improving electrical insulation, and allowing for a simple grounding connection through threaded post-like attachments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plastic bearing seat is used to insulate the rotor shaft from the stator core, then electrical insulation is provided, but the motor tends to oscillate and produce undesirable noise
Solution Approach 1:
The patent employs a composite structure combining metallic stator bushing (for structural stability and noise reduction) with plastic insulation components (for electrical insulation). The metallic bushing is pressed into the stator core and surrounded by insulating end plates with hollow-cylindrical end insulation shafts, creating a composite bearing seat that achieves both mechanical stability and electrical insulation without oscillation-induced noise.
2Reliability
If separate insulation components are used for the stator core and bearing seat, then electrical insulation is ensured, but the manufacturing process becomes complex
Solution Approach 1:
The patent merges multiple functions into integrated components: the insulating end plates are formed integrally with the bearing bushing guide attachments and end insulation shafts, creating a unified plastic bearing seat assembly. This integration reduces the number of separate parts and simplifies the manufacturing process while maintaining effective electrical insulation between the rotor shaft and stator core.
3Strength
If a metallic stator bushing is pressed into the stator core, then structural stability is improved, but electrical insulation between the bushing and stator core is compromised
Solution Approach 1:
The patent introduces insulating end plates and end insulation shafts as intermediary components between the metallic stator bushing and the stator core. These plastic insulation components surround the metallic bushing and contact the stator core, creating an electrical barrier that prevents direct conductive contact while allowing the metallic bushing to provide structural support and stability.
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 significantly reduces noise levels and enhances electrical insulation, enabling a robust attachment of the stator core to the metallic bushing, while allowing for easy grounding and eliminating the need for separate insulation of winding wires.
Implementation Method 1
a common sheath, in particular an extrusion coating, which is composed of plastic and forms the insulation
Implementation Method 2
a stator bushing which can be pressed into a central axial opening in the laminated stator core
Data Source
AI summary
The invention relates to a stator of an electric motor, comprising a laminated stator core (1) which is provided with electrical insulation (8) composed of plastic, and a stator bushing (3) which can be pressed into a central axial opening (2) in the laminated stator core (1), forms a bearing seat for a rotor shaft (10) and is composed of metal. In order to reduce the manufacturing complexity, with the aim at the same time to reduce the amount of noise developed and to improve the electrical insulation of the bearing seat, the invention proposes that the laminated stator core (1) and the metallic stator bushing (3) which is pressed into the laminated stator core (1) are at least partially surrounded by a extrusion coating (8), which is composed of plastic and forms the insulation (8).