Combined PCB Layout for Brushless Power Tool Wiring and Cooling

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Solution Overview

Problem

The complex wiring situation within brushless power tools due to numerous interconnections between components leads to space constraints, weight issues, and increased assembly complexity, hindering the development of compact and efficient designs.

Innovation Solution

The implementation of a combined printed circuit board (PCB) that integrates Hall sensors, power switching elements, and a motor control unit, along with a heat sink and fan for thermal management, reduces wiring complexity and allows for a more compact layout by positioning the PCB between the motor and output unit, enabling improved air flow and flexibility in design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If separate PCBs are used for Hall sensors, power switching elements, and motor control unit, then each component can be independently designed and manufactured, but the wiring complexity increases and space consumption increases within the power tool housing

Engineering Contradiction:

ImproveIndependent component manufacturingVSAvoidWiring complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines the Hall sensor PCB, power switching element PCB, and motor control unit PCB into a single integrated PCB assembly. This merging eliminates the need for multiple separate wiring connections between components, reducing wiring complexity while maintaining the functional independence of each component through separate circuit regions on the same PCB.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of manufacture

If separate PCBs are used for Hall sensors, power switching elements, and motor control unit, then each component can be independently designed and manufactured, but the overall device size and weight increase

Engineering Contradiction:

ImproveIndependent component manufacturingVSAvoidPower tool housing space

Core Design Contradiction:

Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent integrates multiple functional PCBs into a single compact PCB structure, significantly reducing the volume occupied by electronic components in the power tool housing. The combined PCB serves as a single structural unit that houses all necessary electronic components, eliminating the space required for multiple separate PCB assemblies and their interconnecting wiring.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If complex wiring is used to connect multiple components, then each component can be independently positioned, but assembly complexity increases

Engineering Contradiction:

ImproveComponent positioning flexibilityVSAvoidAssembly complexity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple components onto a single PCB, which inherently positions all components relative to each other in a predetermined arrangement. This eliminates the need for complex wiring connections and simplifies assembly, as the PCB can be installed as a single unit with all components already in their correct positions and electrically connected.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If multiple separate PCBs are used, then functional separation is maintained, but thermal management becomes more difficult due to limited space for heat sinks and air flow

Engineering Contradiction:

ImproveFunctional separationVSAvoidThermal management

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent designs the combined PCB with dedicated thermal management regions and heat dissipation pathways for different functional areas. Power switching elements, which generate the most heat, are positioned with adequate spacing and thermal vias, while Hall sensors and control circuits are positioned in cooler regions. The PCB layout incorporates local thermal management features such as heat sinks, thermal pads, and air flow channels tailored to each component's thermal requirements.

Inventive Principle:

Principle #3Local quality

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

This solution results in a more compact, lightweight, and efficiently designed brushless power tool with reduced assembly complexity, enhanced thermal management, and increased flexibility in handle and body dimensions, allowing for higher torque output and improved user experience.

Implementation Method 1

a heat sink secured to an end of the brushless DC motor and a combined printed circuit board (PCB) secured to the heat sink

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

along with a heat sink and fan for thermal management, reduces wiring complexity and allows for a more compact layout by positioning the PCB between the motor and output unit, enabling improved air flow

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS20240204615A1Brushless DC motor power tool with combined PCB design

Publication Date: 2024.06.20 MILWAUKEE ELECTRIC TOOL CORP

AI summary

A power tool with a combined printed circuit board (PCB) that reduces internal wiring of the power tool and provides a large amount of air flow to internal components. In some instances, the combined PCB has a surfboard shape and includes a motor control unit and power switching elements (Field Effect Transistors or FETs). The combined surfboard PCB is located above the trigger, but below the motor and drive mechanism. In other instances, the combined PCB has a doughnut shape and is located coaxially with a motor shaft. The combined PCB may be positioned between a doughnut-shaped control PCB and the motor.