Brushless Power Tool Motor Assembly for Heat Dissipation and Alignment
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Solution Overview
Problem
Existing power tools with electric motors face challenges in efficient heat dissipation and alignment during assembly, leading to potential misalignment and reduced manufacturability.
Innovation Solution
The design incorporates a brushless direct current (DC) electric motor with a heat sink positioned between the stator assembly and circuit board, and unique angular spacing of mounting legs, ribs, and tabs ensures proper alignment and secure coupling, enhancing heat dissipation through a molded fan and magnet retention structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat sink is positioned between the stator assembly and circuit board, then heat dissipation is improved, but device complexity increases
Solution Approach 1:
The heat sink is integrated directly into the stator assembly structure, merging the thermal management function with the existing structural component rather than adding a separate discrete heat dissipation device. This reduces overall device complexity while maintaining effective heat dissipation.
Solution Approach 2:
The stator assembly serves multiple functions: it provides structural support, magnetic flux path, and now also serves as a heat dissipation structure through the integrated heat sink. This multi-functionality eliminates the need for separate dedicated heat dissipation components.
2Manufacturing precision
If unique angular spacing of mounting legs, ribs, and tabs is used, then alignment precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The mounting legs, ribs, and tabs are positioned at unique angular spacings rather than symmetric intervals, creating an asymmetric pattern that provides inherent alignment features. This asymmetric configuration ensures precise alignment during assembly while the features remain simple geometric shapes suitable for standard manufacturing processes.
Solution Approach 2:
The mounting legs, ribs, and tabs are pre-positioned on the stator assembly during manufacturing, establishing alignment references before final assembly. This preliminary positioning of alignment features ensures that when components are assembled, proper alignment is achieved without requiring complex adjustment procedures.
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 improves heat dissipation and ensures proper alignment during assembly, enhancing the performance and manufacturability of power tools by preventing misalignment and improving thermal management.
Implementation Method 1
a heat sink positioned between the stator assembly and circuit board... in thermal contact with the circuit board
Implementation Method 2
enhancing heat dissipation through a molded fan
Implementation Method 3
windings wrapped about the stator body to form a plurality of coils... brushless direct current (DC) electric motor
Data Source
AI summary
An electric motor assembly includes a circuit board, a rotor assembly, and a stator assembly having a first end coupled to the circuit board and a second end opposite the first end. The stator assembly also includes an annular stator body having a plurality of inwardly projecting teeth. The stator assembly further includes windings wrapped about the stator body to form a plurality of coils. The stator assembly also includes a terminal coupled to an outer periphery of the stator body and extending longitudinally between the first end and the second end. The terminal is coupled to the circuit board at the first end and is coupled to the windings at the second end to electrically connect the windings to the circuit board. The terminal is molded to an attachment member, and the attachment member is molded to the outer periphery of the stator body.