Stator Winding Topology for Handheld Tool Motors
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Solution Overview
Problem
Existing electric motor designs for handheld tools face challenges in maximizing copper filling in stator coils due to limited wire diameter from pin winding processes, leading to reduced winding numbers and increased complexity with multiple layers of printed conductors for parallel coil connections.
Innovation Solution
A stator design with a multiplicity of stator coils connected in parallel, where winding wires are guided from one stator tooth to connecting terminals and back, reducing the need for soldering and allowing a simpler terminal configuration without molded plastic or multiple circuit board layers, using a delta connection with terminal pairs and an insulating piece for guiding the wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pin winding method is used with limited wire diameter, then copper filling is maximized, but winding number decreases
Solution Approach 1:
The patent divides the coil winding into multiple parallel circuits instead of using a single series winding. Each parallel circuit contains a subset of windings, allowing the total copper filling to be distributed across multiple paths. This segmentation enables both high copper filling (by using available wire diameter effectively) and high winding number (by creating multiple parallel pathways for current flow).
Solution Approach 2:
The patent transitions from a single-dimensional series connection to a multi-dimensional parallel connection structure. By organizing windings into multiple parallel branches with systematic connection patterns, the design adds a dimensional aspect to the wiring topology, enabling simultaneous optimization of copper utilization and winding count.
2Adaptability or versatility
If multiple layers of printed conductors are used for parallel coil connections, then connection complexity increases, but production cost and manufacturing complexity increase
Solution Approach 1:
The patent extracts the connection function from the printed circuit board and implements it directly through the winding structure itself. The parallel connections are achieved through the physical arrangement and termination of coil ends, eliminating the need for complex multi-layer PCB routing. This extraction of the connection function reduces device complexity while maintaining parallel connection capability.
Solution Approach 2:
The patent merges the winding structure with the connection structure. Instead of separating the coil windings from their connection paths, the design integrates both functions into a unified structure where the coil ends and their connections form the parallel circuit topology directly, eliminating the need for separate circuit board layers.
3Adaptability or versatility
If multiple layers of printed conductors are used, then connection capability is achieved, but manufacturing cost increases
Solution Approach 1:
The patent removes the expensive multi-layer printed circuit board component from the design and replaces it with a simpler direct connection approach. The connection capability is achieved through the inherent structure of the parallel-wound coils and their terminations, eliminating the need for costly multi-layer PCB fabrication and assembly processes.
Solution Approach 2:
The patent replaces expensive, complex multi-layer circuit boards with a simpler, more economical connection structure that can be implemented directly during the winding process. This substitution uses basic electrical connection techniques rather than expensive printed circuit technology, significantly reducing manufacturing costs.
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 design simplifies production, reduces costs, and achieves a more efficient coil winding topology by minimizing the number of wires to be soldered and eliminating the need for multiple printed conductor layers, while maintaining effective power and torque delivery.
Implementation Method 1
stator coils (18) wound on the stator teeth (12)
Data Source
AI summary
A stator is provided for a multiphase electric motor. The stator has a stator core having a multiplicity of stator teeth situated along a circumference of the stator core, coils wound on the stator teeth, and a multiplicity of connecting terminals for contacting the electric motor in a delta connection, with a parallel circuit of the coils per phase. Here, a respective winding wire of the coils is connected directly to the connecting terminal at each connecting terminal. In addition, a multiplicity of coils is connected in parallel to at least one of the connecting terminals, and the connecting terminals are provided for at least one of the phases in each case as a terminal pair made up of a main terminal and a secondary terminal connected to the main terminal by an electrically conductive connecting piece. In addition, an associated winding method is described.