Cordless BLDC Power Tool Architecture for High Current Output
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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, particularly in hand-held cordless tools, where balancing motor control electronics, power source requirements, and motor capabilities to achieve desired performance and operational characteristics is difficult.
Innovation Solution
A cordless, hand-held power tool incorporating a brushless direct current (BLDC) motor, electronics for controlling and monitoring operation, and a removable battery pack, designed to balance the capabilities of the motor, battery pack, and electronics to provide high-performance power output without failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If brushless-type motors are used in power tools, then power output and efficiency are improved, but cost and design complexity increase
Solution Approach 1:
The patent divides the power tool system into modular components: the BLDC motor as a separate module, the battery pack as a removable module, and the tool housing as a separate module. This segmentation allows each component to be optimized independently while maintaining overall system performance, reducing the design complexity burden on any single component.
Solution Approach 2:
The patent employs parameter optimization in the BLDC motor design, including winding configurations, magnet arrangements, and controller parameters, to achieve high power output within compact dimensions. By carefully adjusting these parameters, the motor delivers superior performance without proportionally increasing size or complexity.
2Power
If brushless-type motors are used in hand-held power tools, then performance is improved, but integration of motor control electronics and power source becomes more difficult
Solution Approach 1:
The control electronics are integrated into the motor assembly as a separate module, while the battery pack remains a removable component. This segmentation simplifies the integration challenge by isolating the electronic control system from the power source, allowing each to be optimized and tested independently before final assembly.
Solution Approach 2:
The battery pack is designed as a universal, removable module that can be used across different hand-held power tools. This multi-functionality approach standardizes the power source interface and control electronics, reducing integration complexity while maintaining high performance across multiple tool applications.
3Power
If high power output is achieved in hand-held power tools, then instantaneous power increases, but thermal management and durability challenges arise
Solution Approach 1:
The patent incorporates thermal management features directly into the high-power BLDC motor design, converting the heat generated by high instantaneous power into a manageable parameter through integrated cooling channels and thermally conductive materials. This approach transforms the harmful thermal effect into a controlled design parameter.
Solution Approach 2:
The patent optimizes multiple parameters including winding resistance, magnet strength, and controller duty cycles to maximize instantaneous power output while maintaining thermal performance within acceptable limits. By adjusting these parameters, the system achieves high power bursts without compromising durability or requiring excessive cooling infrastructure.
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 hand-held power tool achieves high instantaneous and continuous power outputs in a compact, lightweight design, exceeding previous cordless tools, with sustained power of at least 300 Watts and short-duration power of up to 700 Watts, while maintaining durability and 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, a 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 a 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).