Brushless Motor Stator Winding With Uniform Tooth Tip Gaps
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Solution Overview
Problem
The existing brushless motor technology faces challenges in uniformly winding coils around stator cores with non-uniformly spaced pole teeth, leading to instability and increased tension in magnet wire, which can result in wire breakage and reduced productivity due to the asymmetric shape of the tooth tips in laminated cores.
Innovation Solution
The solution involves forming auxiliary tooth tip sections on the stator core using materials like resin or rubber to create uniform gaps between the tooth tips, allowing for stable and uniform coil winding, even with asymmetric pole teeth, by integrating these sections through methods such as insert molding, coating, or bonding, which prevents the center former from rattling during the winding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the stator core uses asymmetric pole teeth to increase the number of pole teeth facing rotor magnets, then the holding torque is improved, but the coil winding process becomes unstable due to non-uniform gaps between tooth tips
Solution Approach 1:
The patent introduces a center former as an intermediary tool during the coil winding process. This center former is inserted into the stator core and extends beyond the tooth tips to provide a stable reference surface. The center former mediates between the asymmetric tooth tips and the winding machine, ensuring uniform gaps and stable coil winding despite the asymmetric pole tooth configuration that improves holding torque.
2Force
If asymmetric pole teeth are used to improve holding torque, then more pole teeth can face rotor magnets, but the magnet wire tension increases and wire breakage occurs
Solution Approach 1:
The center former acts as a mediator that distributes and stabilizes the mechanical interaction during coil winding. By providing a uniform reference surface beyond the asymmetric tooth tips, it prevents localized stress concentration that would otherwise cause magnet wire breakage, while still allowing the asymmetric pole teeth to function for improved holding torque.
Solution Approach 2:
The center former is pre-positioned in the stator core before the coil winding process begins. This preliminary action establishes uniform gaps and a stable geometric reference in advance, preventing wire tension issues and breakage during the subsequent winding operation.
3Force
If asymmetric pole teeth are used to improve holding torque, then cogging torque is enhanced, but productivity decreases due to increased wire breakage and slower winding speed
Solution Approach 1:
The center former serves as a mediator that enables high-speed automated winding by providing stable geometric reference. This allows the winding machine to operate at normal speeds without worrying about wire breakage, thus maintaining productivity while the asymmetric pole teeth enhance cogging torque.
Solution Approach 2:
By pre-installing the center former with uniform extensions beyond all tooth tips, the system prepares the winding path in advance. This eliminates the need for slow, careful manual winding and enables fast automated coil winding, thereby improving productivity while preserving the cogging torque benefits of asymmetric pole teeth.
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
A brushless motor that can uniformly wind a coil winding at a low cost even with a stator core in which intervals between tooth tips of a plurality of pole teeth provided in a circumferential direction of an annular section to protrude in a radial direction differ. An auxiliary tooth tip section (4c) is formed integrally on a tooth tip (4f) of a required pole tooth (4a) of a stator core (4) in which a plurality of pole teeth (4a) are provided in a circumferential direction of an annular section (4b) to protrude in a radial direction, and in which circumferential intervals between adjacent tooth tips (4f) are not uniform, and gaps (t) between the tooth tips (4f) of all the pole teeth (4a) of the stator core (4) are formed uniform.