Insulated Rotor Shaft Assembly for Verifiable Tool Isolation
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Solution Overview
Problem
Handheld electric tools face challenges in ensuring electrical safety due to complex designs with multiple insulators of varying dimensions, making compliance with safety standards difficult, and wear can compromise safety features.
Innovation Solution
A rotor shaft assembly with an electrical insulator connected to the rotor shaft, extending outside the stator assembly, provides electrical insulation to connected tools or accessories, allowing for easy verification of safety compliance and protection against electrical shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple insulators of varying dimensions are used in the electric motor design, then electrical safety is improved, but device complexity increases and verification of compliance becomes difficult
Solution Approach 1:
The patent combines multiple insulating functions into a single integrated electrical insulator that is connected to the rotor shaft assembly. This insulator simultaneously provides insulation between the rotor shaft and stator assembly, and between connected tools or accessories and the electric motor, replacing what would traditionally require multiple separate insulators of varying dimensions.
Solution Approach 2:
The electrical insulator is designed to perform multiple safety functions: it insulates the rotor shaft assembly from the stator assembly, and also insulates any tool or accessory connected to the rotor shaft assembly from the electric motor. This multi-functional design simplifies the overall structure while maintaining comprehensive electrical safety.
2Reliability
If multiple insulators with variable dimensions are used, then electrical safety is improved, but ease of verification of compliance deteriorates
Solution Approach 1:
By consolidating multiple insulating elements into a single electrical insulator with defined dimensions, the patent makes it easier to verify compliance with safety standards. The insulator's specific dimensions (first dimension along the rotor shaft, second dimension radially) can be clearly measured and verified, replacing the complexity of verifying multiple insulators with varying dimensions.
3Ease of manufacture
If traditional insulation design is used, then manufacturing is complex, but electrical safety is maintained; with the new design, ease of manufacture is improved but structural complexity changes
Solution Approach 1:
The electrical insulator is designed with a segmented structure that includes a first portion connected to the rotor shaft assembly and a second portion configured to connect to the tool or accessory. This segmentation allows the insulator to be manufactured as a modular component with specific dimensional requirements, simplifying the manufacturing process while maintaining the necessary insulation properties.
Data Source
AI summary
There is provided a solution for electrical insulation for an output shaft, tool and/or accessory driven by an electric motor, and the presence of the electrical insulation is also easy to verify. A rotor shaft assembly for an electric motor includes at least one section that is configured to extend in an axial direction of the rotor shaft assembly outside of a stator assembly of the electric motor, when the rotor shaft assembly is rotatably mounted inside the stator assembly. An electrical insulator is connected to the at least one section and the electrical insulator is configured to connect to an output shaft for connecting with a tool and/or accessory, or configured to connect directly to a tool and/or accessory to be driven by the electric motor.