Brushless Motor Double Insulation for Low-Profile Power Tools
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Solution Overview
Problem
Electrically powered random orbital sanders have a higher profile and weight compared to pneumatic sanders, leading to increased user fatigue and wobble due to the height and weight of mechanically commutated motors, making them less ergonomic and more tiring to use.
Innovation Solution
A low-profile power tool with a brushless motor featuring a rotor with permanent magnets and a stator with laminations and windings, incorporating double insulation and a serpentine path for electrical components to minimize height and weight, and an ergonomic design for improved grip and reduced wobble.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a mechanically commutated motor is used in an electrically powered random orbital sander, then the motor can provide sufficient power, but the height and weight of the tool increase, leading to user fatigue and wobble
Solution Approach 1:
The patent replaces the mechanically commutated motor with an electronically commutated brushless motor. This substitution eliminates the need for a mechanical commutator and brushes, allowing for a more compact motor design that reduces both the height and weight of the overall tool while maintaining sufficient power output for sanding applications
2Power
If a mechanically commutated motor is used in an electrically powered random orbital sander, then the motor can provide sufficient power, but the height of the tool increases, leading to user fatigue and wobble
Solution Approach 1:
The patent replaces the mechanically commutated motor with an electronically commutated brushless motor. This substitution eliminates the need for a mechanical commutator and brushes, allowing for a more compact motor design that reduces both the height and weight of the overall tool while maintaining sufficient power output for sanding applications
3Reliability
If double insulation is implemented with a serpentine path for electrical components, then electrical safety is improved, but the device complexity increases
Solution Approach 1:
The patent combines the double insulation requirements with the motor housing structure itself. The housing serves as both the structural enclosure and the insulating barrier, integrating safety functions into the existing design rather than adding separate insulation components. This reduces overall complexity while maintaining electrical safety
Solution Approach 2:
The patent introduces an insulating barrier or serpentine path as an intermediary element between live electrical components and the user-accessible portions of the tool. This intermediary structure provides the required electrical isolation while being integrated into the motor assembly, minimizing additional complexity
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 low-profile design reduces user fatigue and wobble, allowing for a more comfortable and efficient sanding experience by distributing weight optimally and minimizing the motor's height, while maintaining sufficient power and performance.
Implementation Method 1
an electronically commutated motor disposed therein. The motor has a rotor and a stator. The rotor has permanent magnets disposed around a periphery of the rotor and a shaft. The stator has a lamination stack and windings wound therein
Implementation Method 2
The rotor has permanent magnets disposed around a periphery of the rotor and a shaft
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A power tool has a housing having an electronically commutated motor disposed therein. The motor has a rotor and a stator. The rotor has permanent magnets. The stator has a lamination stack and windings wound therein. Features are provided to provide double insulation.