Brushless Power Tool Motor With Angled Stator 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, and a non-conductive terminal mount for efficient power distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If brushed DC motors are used in power tools, then ease of manufacture and low cost are achieved, but brush wear reduces longevity and electrical sparking causes noise and reliability issues

Engineering Contradiction:

Improveease of manufactureVSAvoidlongevity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the mechanical brush contact system with an electronic commutation system using Hall effect sensors and electronic switches. This substitution eliminates physical wear while maintaining the motor's rotational control functionality, thereby improving longevity without significantly complicating manufacturing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces Hall effect sensors as intermediary components that detect rotor position and provide feedback to the electronic control system. This intermediary mechanism enables brushless operation by allowing electronic commutation based on precise positional information, resolving the contradiction between manufacturing simplicity and reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If brushed DC motors are used in power tools, then ease of manufacture and low cost are achieved, but electrical sparking from brushes creates noise and reduces reliability

Engineering Contradiction:

Improveease of manufactureVSAvoidelectrical noise

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent converts the harmful electrical sparking into beneficial controlled electronic switching. By using electronic switches driven by Hall effect sensor feedback, the system achieves precise commutation without sparks, transforming the problematic electrical contact into a clean, controlled electronic process that reduces noise and improves reliability

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If brushless DC motors with electronically controlled switches are used, then longevity and reliability are improved, but device complexity increases

Engineering Contradiction:

ImprovelongevityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates multiple functions into the controller component, which handles electronic commutation, speed control, and protection functions. This multi-functionality consolidates the complexity into a single manageable unit rather than distributing it across multiple separate components, making the system more maintainable and easier to manufacture as a complete assembly

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the electronic control circuitry, Hall effect sensor processing, and motor drive functions into an integrated controller assembly. This merging of functions reduces the number of discrete components and interconnections, thereby managing device complexity while maintaining the reliability benefits of brushless operation

Inventive Principle:

Principle #5Merging (Combining)

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 solution 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

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The controller is configured to selectively apply power to the coils based on input from Hall effect sensors

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS20240063679A1Brushless motor for a power tool

Publication Date: 2024.02.22 MILWAUKEE ELECTRIC TOOL CORP

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.