Outer-Rotor BLDC Blower Assembly for Compact Power Tools
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power tool drive units face challenges in efficiently combining motor and blower assembly functionality, particularly in terms of rotor design, magnet configuration, and airflow management.
Innovation Solution
The drive unit incorporates a brushless direct current (BLDC) outer rotor motor with a rotor core formed from laminations, magnets coupled to the rotor core, and an overmold housing that secures the magnets. The blower assembly is integrated with the motor, featuring a blower fan with blades extending radially outward from the motor, optimized for airflow and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional motor and blower assembly configurations are used, then the device structure is simpler, but the rotation speed and torque output are lower
Solution Approach 1:
The patent combines the motor rotor and blower assembly into a single integrated rotor structure. The blower blades are directly formed as part of the rotor assembly, eliminating the need for separate motor and blower components. This merging achieves higher torque output and rotation speed while reducing overall device complexity through integration.
Solution Approach 2:
The rotor assembly serves multiple functions simultaneously: it acts as both the motor rotor for generating rotational force and the blower assembly for moving air. The magnets are positioned on the rotor to provide both motor function and blower function, making the structure multi-functional and improving power output without proportionally increasing complexity.
2Power
If multiple magnets per pole are used, then the torque output increases, but the manufacturing complexity increases
Solution Approach 1:
The patent merges multiple magnets into single pole assemblies where magnets of opposite polarity are positioned adjacent to each other on the rotor. This merging approach allows for increased torque output through multiple magnets per pole while simplifying the manufacturing process by treating each pole assembly as a single unit rather than managing individual magnets separately.
Solution Approach 2:
The rotor is segmented into multiple poles, with each pole containing multiple magnets. This segmentation allows for systematic arrangement of magnets to achieve desired torque characteristics while maintaining ease of manufacture through modular pole assembly construction.
3Productivity
If blower fan blades extend radially outward from motor, then aerodynamic efficiency improves, but the device volume increases
Solution Approach 1:
The blower fan blades are merged with the motor rotor structure, with blades extending radially outward from the rotor. This integration allows the blower assembly to share the same rotational space as the motor, improving aerodynamic efficiency for airflow generation while minimizing the overall volume of the drive unit by eliminating separate housing requirements.
Solution Approach 2:
The blower assembly is nested within the motor structure, with the blower blades positioned on the outer periphery of the rotor. This nesting arrangement allows the blower functional elements to be contained within the motor's rotational envelope, achieving efficient airflow generation without proportionally increasing the drive unit volume.
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 configuration enhances the power tool's performance by achieving higher rotation speed and torque output, while also improving aerodynamic efficiency and reducing noise and vibration, thus extending the drive unit's lifespan.
Implementation Method 1
The rotor is configured to be driven by the stator
Implementation Method 2
The rotor has a rotor core, a plurality of magnets, and an overmold housing that couples the plurality of magnets to the rotor core
Implementation Method 3
The blower assembly includes a plurality of blower fan blades. The blower assembly is configured to be driven by the motor
Data Source
AI summary
A drive unit for a power tool that includes a motor and a blower assembly. The motor includes a rotor shaft, a stator, and a rotor. The rotor shaft extends along an axis of rotation. The stator is mounted to the rotor shaft. The rotor at least partially surrounds the stator. The rotor has a rotor core, a plurality of magnets, and an overmold housing that couples the plurality of magnets to the rotor core to form poles having more than one magnet per pole. The blower assembly includes a plurality of blower fan blades. The blower assembly is configured to be driven by the motor.