Cordless BLDC Power Tool Architecture for High Torque Without Overheating
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Solution Overview
Problem
Brushless-type motors have not been widely used in power tools due to high cost and design challenges related to motor control electronics, power source requirements, and achieving desired performance and operational characteristics, particularly in hand-held cordless tools where size, weight, and performance limitations are magnified.
Innovation Solution
A cordless hand-held power tool incorporating a brushless direct current (BLDC) motor, a removable battery pack, and advanced electronics that balance motor, battery, and electronics capabilities to deliver high-power and high-torque performance without thermal failure, using a switching array and controller to manage power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If brushless-type motors are used in power tools, then performance and operational characteristics are improved, but cost and design complexity increase
Solution Approach 1:
The motor control system is segmented into distinct functional modules: a controller for high-level decision making, a motor controller for intermediate control signals, and a switching array for final power delivery. This segmentation distributes complexity across multiple manageable components rather than concentrating it in a single complex unit.
Solution Approach 2:
The patent introduces intermediary control components between the power source and the motor. The controller and motor controller act as intermediaries that manage the complex power electronics functions, simplifying the overall system architecture by breaking down the control task into manageable stages.
2Power
If hand-held power tools are designed for high power output, then performance is improved, but size and weight increase
Solution Approach 1:
The patent employs parameter changes in the motor design, specifically using brushless direct current (BLDC) motor technology with optimized magnetic fields and winding configurations. These parameter changes enable higher power density, allowing the motor to deliver more power in a smaller, lighter package compared to conventional brushed motors.
Solution Approach 2:
The patent replaces the mechanical brush-and-commutator system with an electronic switching system. This substitution eliminates the need for physical contact components, reducing mechanical friction and wear while enabling more efficient power transfer, which contributes to higher power output in a compact design.
3Power
If hand-held power tools are designed for high power output, then performance is improved, but the tool becomes less portable
Solution Approach 1:
The patent utilizes parameter changes in battery technology and motor efficiency to improve power density. By optimizing these parameters, the system delivers high power output while minimizing the size and weight of the power source and motor, thereby maintaining portability and ease of operation.
Solution Approach 2:
The replacement of mechanical brush components with electronic switching reduces the overall mechanical complexity and weight of the motor assembly. This substitution contributes to a lighter tool that is easier to handle and more portable, while still delivering high power performance.
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 tool achieves high instantaneous and continuous power outputs in a compact, lightweight design, exceeding previous hand-held power tools in performance capabilities while preventing thermal failure.
Implementation Method 1
a brushless direct current (BLDC) motor
Data Source
AI summary
A cordless, hand-held power tool, such as a hammer drill/driver, an impact driver, an impact wrench, etc., that includes a brushless direct current (“BLDC”) motor. Each of the hand-held power tool includes a removable and rechargeable battery pack, electronics, and a BLDC motor that have been designed and balanced to produce high-performance-capable (e.g., high-power, high-current, high-torque) hand-held power tool. The hand-held power tool is capable of delivering high instantaneous (i.e., short duration) current to the BLDC motor for short-duration high power operation and high continuous (i.e., long duration) current to the BLDC motor for long duration high power operation. Additionally, the short and long duration power is capable of being provided in a smaller (in size) and lighter (in weight) power tool.