Slotless Motor Medium Pathway Nesting
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Solution Overview
Problem
Existing brushless slotless motors for dental handpieces face challenges in downsizing and performance enhancement due to ineffective regions on the magnetic circuit caused by pathways for water, air, and electric wires, which occupy space without contributing to motor output.
Innovation Solution
The motor employs a non-lap winding configuration with medium pathways embedded between adjacent coils, eliminating excessive stress on coils and allowing for reduced motor case diameter while maintaining a larger outer diameter for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If pathways for water, air, and electric wires are disposed at the outside of the stator core, then the motor case diameter can be reduced, but the effective length of the magnetic circuit is shortened and performance is reduced
Solution Approach 1:
The patent embeds the medium pathways inside the stator core by nesting them within the coil structure. The pathways are positioned to pass through the interior of the coils, allowing the magnetic circuit to extend over the entire length of the coils while accommodating water, air, and electric wire pathways within the same spatial envelope, thus eliminating the trade-off between compactness and performance.
Solution Approach 2:
The patent repositions the pathways from the radial dimension (outside the stator core) to the axial dimension (inside the coils along the axis). This dimensional change allows the pathways to be integrated within the coil length without reducing the effective magnetic circuit length, enabling both compact motor case diameter and full performance utilization.
2Device complexity
If lap winding is used to integrate pathways within coils, then the pathways can be embedded in the coil structure, but excessive stress is applied to the coils and production cost increases
Solution Approach 1:
The patent segments the pathways from the coil winding structure itself. Instead of integrating pathways into the coil ends through complex lapping, the pathways are positioned as separate entities within the interior space of the coils, allowing the coil winding to maintain its structural integrity and avoid excessive stress while still achieving integration of multiple functions within the same space.
3Device complexity
If lap winding with protruding coil ends is used, then pathways can be integrated, but the effective length of the motor is reduced due to inactive coil end regions
Solution Approach 1:
Instead of having coils protrude beyond the stator core to accommodate pathways (which creates inactive regions), the patent inverts the approach by having the pathways pass through the interior of the coils while the coils extend fully along the stator core. This ensures that the entire length of the coils contributes to the magnetic circuit, eliminating inactive regions while still integrating the pathways.
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 enables further downsizing and performance enhancement by utilizing previously ineffective regions for motor output, improving torque output and reducing production costs while maintaining high-quality coil production.
Implementation Method 1
A plurality of coils 31 to 33 are disposed on the outer circumference of the holder member 34. Each of the plurality of coils 31 to 33 is disposed inside the stator core 301 along the rotation direction of the rotor 2.
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
Provided are an electric motor that enables to promote a further downsizing and performance enhancement, and a dental device that includes the electric motor. A brushless slotless electric motor 10 includes: a stator 3 that includes a stator core 301 and a plurality of coils 31 to 33, the plurality of coils 31 to 33 being disposed at an inside of the stator core 301; a rotor 2 that includes a shaft 21, the rotor 2 being rotated around the shaft 21 with respect to the stator 3; and a medium pathway 40 through which a medium passes, the medium being supplied for actualizing a function of a dental handpiece 9A to which the electric motor 10 is applied. The plurality of coils 31 to 33 are adjacent to each other in a rotation direction of the rotor 2 so as not to lap mutually. The medium pathway 40 is disposed between the adjacent coils 31 to 33.