Brushless Motor PCB Delta Coil Vibration Resistance
Solution Overview
Problem
Existing brushless motors face challenges in maintaining firm connections between coils due to the use of smaller diameter wires and additional wires connected in parallel, which are inconvenient and prone to vibration-induced breakage during operation of power tools like electric drills and hammers.
Innovation Solution
A brushless motor design featuring a stator core with 3M teeth, a rotor, and a printed circuit board (PCB) that connects 3M coils in delta configuration with three-phase windings, where each coil is wound around individual teeth and connected via the PCB, with semicircular connection wires and apertures for secure electrical connections, reducing the need for spot welding and enhancing resistance to vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If wire of relatively greater diameter is used to make the coils, then the current carrying capacity is improved, but it becomes difficult for common winding machines to wind the coils and the bobbin and insulating layer are easily damaged
Solution Approach 1:
The patent divides the coil structure into multiple parallel wires instead of using a single thick wire. Each phase winding consists of multiple coils connected in parallel, where each coil is made of thinner wire that is easier to wind. This segmentation allows the use of standard winding machines while achieving the required current carrying capacity through parallel connections.
2Ease of manufacture
If wire of relatively lesser diameter is used to produce the coils, then the coil winding becomes easier, but additional wires must be employed to connect corresponding coils in parallel by spot welding which is inconvenient and time-consuming
Solution Approach 1:
The patent replaces the mechanical spot welding process with a PCB-based electrical connection system. The PCB provides pre-fabricated connection terminals that accept wire ends through insertion and fixation, eliminating the need for time-consuming spot welding operations. This substitution significantly reduces assembly time and improves manufacturing efficiency.
3Quantity of substance
If additional wires are used to connect corresponding coils in parallel, then the current distribution is improved, but the additional wire vibrates intensely during operation which easily breaks the connection between the coil and additional wire
Solution Approach 1:
The patent introduces the PCB as an intermediary connection structure between the coils and external circuits. The PCB provides a rigid, stable mounting platform with dedicated connection terminals that securely hold the wire ends. This intermediary structure eliminates the vibration and movement issues associated with direct wire-to-wire connections, ensuring reliable electrical connections during motor operation.
Solution Approach 2:
The patent uses the PCB as a flexible yet stable substrate that provides both mechanical support and electrical connection. The PCB's structure allows for secure fixation of wire ends through apertures and connection terminals, while the overall rigid structure resists vibration. This combination provides both the electrical parallel connection capability and the mechanical stability needed for reliable operation.
4Reliability
If spot welding is used to connect additional wires to coils, then the electrical connection is achieved, but the process is inconvenient and time-consuming
Solution Approach 1:
The patent replaces the spot welding process with a mechanical insertion and fixation system using the PCB. Connection terminals on the PCB accept wire ends through simple insertion, followed by fixation using connection wires or clips. This mechanical system is much faster and more convenient than spot welding, significantly improving assembly speed and productivity while maintaining reliable electrical connections.
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 solution provides robust and efficient connections between coils, making it easier to assemble and operate power tools by eliminating the need for time-consuming spot welding and reducing the risk of connection breakage due to vibration, while allowing for efficient control of currents using power transistors on the PCB.
Implementation Method 1
a printed circuit board (PCB) fixed to the stator core and electrically connected to the 3M coils such that the 3M coils are connected in delta and correspond to three phase windings
Implementation Method 2
3M coils respectively wound around the 3M teeth; and a rotor received in the stator core
Data Source
AI summary
A brushless motor includes a stator core having 3M teeth, with M being an integer not less than 2, a rotor received in the stator core, 3M coils respectively wound around the 3M teeth, and a printed circuit board (PCB) fixed to the stator core and electrically connected to the 3M coils such that the 3M coils are connected in delta and correspond to three phase windings. Each phase includes at least two coils connected in parallel.