Brushless Power Tool Motor With Angled Terminal Mount
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Solution Overview
Problem
Brushed DC motors in power tools face issues such as reduced longevity due to worn-out brushes and electrical noise from sparking, which affects the tool's performance and reliability.
Innovation Solution
The implementation of a brushless DC motor with electronically controlled switches that selectively apply power to the motor coils, eliminating the need for brushes and reducing electrical noise, integrated within a power tool housing with a controller, stator, and rotor assemblies, along with a non-conductive terminal mount and angled terminals for efficient power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brushed DC motors are used in power tools, then ease of manufacture and low cost are achieved, but brush wear reduces longevity and sparking causes electrical noise
Solution Approach 1:
The patent replaces the mechanical brush contact system with an electronic commutation system using Hall effect sensors and electronically controlled switches. This substitution eliminates the mechanical wear of brushes while maintaining the motor's rotational function, directly resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The patent changes the operational parameters of the motor from mechanical contact-based commutation to electronic field-based commutation. By altering the fundamental operating mechanism from physical brush contact to electronic switching controlled by sensor feedback, the system achieves wear-free operation while managing complexity through electronic control.
2Reliability
If brushed DC motors are used in power tools, then low cost and ease of manufacture are achieved, but sparking from brush contact generates electrical noise
Solution Approach 1:
The patent replaces the mechanical brush contact system with an electronic commutation system using Hall effect sensors and electronically controlled switches. This substitution eliminates the mechanical wear of brushes while maintaining the motor's rotational function, directly resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The patent converts the harmful sparking effect into a beneficial sensorless detection mechanism by utilizing the back-EMF generated during commutation. This approach transforms the previously harmful electrical noise into useful feedback signals for determining rotor position, eliminating the need for physical brushes while maintaining cost-effectiveness.
3Duration of action of moving object
If brushless DC motors with electronically controlled switches are used, then brush wear is eliminated and longevity is improved, but device complexity increases
Solution Approach 1:
The patent implements a sensorless control system that uses the motor's own back-EMF signals to determine rotor position and control commutation timing. This self-service approach eliminates the need for external sensors while maintaining precise electronic control, reducing the complexity increase associated with brushless operation.
Solution Approach 2:
The patent incorporates feedback control mechanisms where the controller monitors current consumption and voltage signals to determine optimal commutation timing. This feedback system enables precise motor control without mechanical brushes, extending lifespan while managing complexity through intelligent control algorithms rather than additional mechanical components.
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 brushless DC motor design enhances the longevity and reliability of power tools by eliminating brush wear and electrical noise, providing a more efficient and quieter operation.
Implementation Method 1
A brushless DC motor uses electronically controlled switches to selectively apply power to coils of a motor to drive a rotor
Data Source
AI summary
Power tools described herein include a housing, a brushless direct current (DC) motor, a non-conductive terminal mount, and a plurality of terminals. The housing has a motor housing portion, a handle portion, and a battery pack interface. The brushless DC motor is located within the motor housing portion and has a rotor and a stator. The non-conductive terminal mount is located on an outer peripheral surface of the stator and includes an angled surface. The angled surface is not substantially parallel to a longitudinal axis of the motor. The plurality of terminals is mounted on the angled surface of the terminal mount. Each of the terminals is angled in a first direction such that the terminals are not substantially parallel to the longitudinal axis of the motor.