Brushless Motor 6-Slot 2-Pole Rotor Noise Reduction
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Solution Overview
Problem
Traditional brushless motors experience high electromagnetic noise and unbalanced magnetic forces at high rotational speeds, leading to reduced user experience and bearing life.
Innovation Solution
A brushless motor design featuring a stator with concentrated windings and a rotor with semicircular magnets and a single bearing device closer to one end of the motor shaft, along with a balancing ring, to reduce noise and vibrations, and enhance heat dissipation and assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional brushless motor structure is used, then high rotational speed is achieved, but electromagnetic noise increases and user experience deteriorates
Solution Approach 1:
The patent applies asymmetry by using semicircular magnets instead of traditional circular magnets. The semicircular shape creates a more balanced magnetic field distribution that reduces electromagnetic noise while maintaining high rotational speed capability. This asymmetric geometry modifies the magnetic flux pattern to eliminate the sharp noise characteristics associated with traditional designs.
Solution Approach 2:
The patent changes key geometric parameters of the magnetic circuit, specifically the magnet shape from circular to semicircular, and optimizes the stator slot geometry. These parameter changes fundamentally alter the magnetic field distribution and reduce the electromagnetic noise generated at high speeds, while preserving the motor's speed performance.
2Speed
If traditional rotor structure is used, then high output speed is achieved, but unbalanced magnetic force increases and bearing life reduces
Solution Approach 1:
The patent implements a counterbalancing mechanism by strategically positioning and shaping the semicircular magnets to create balanced magnetic forces. The asymmetric semicircular geometry, when properly arranged, generates counteracting magnetic forces that offset unbalanced pull, thereby reducing the load on bearings and extending their operational life while maintaining high output speed.
Solution Approach 2:
The patent employs composite construction in the rotor assembly, combining semicircular magnets with specifically designed stator structures. This composite approach creates a balanced magnetic circuit that reduces unbalanced forces and improves overall system reliability, including bearing life, while preserving high-speed performance.
3Temperature
If concentrated windings are used, then heat dissipation is improved, but manufacturing complexity increases
Solution Approach 1:
The patent divides the stator into multiple slots with concentrated windings arranged in each slot. This segmentation allows for improved heat dissipation through better air flow paths and reduced heat concentration in any single area. The modular slot structure also facilitates easier manufacturing and assembly compared to traditional distributed windings.
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 design significantly reduces operational noise and extends motor life by minimizing iron loss and unbalanced pull, while allowing higher rotational speeds and improved heat dissipation, resulting in enhanced user experience and longer tool usage.
Implementation Method 1
a stator (26), and a rotor. The rotor is placed at a center of the motor and is adapted to rotate relative to the stator (26). The rotor includes a motor shaft (20)... There are windings (not shown in Fig. 1) wounded on each of these teeth (28) in concentrated manner
Implementation Method 2
adjacent to the other end of the motor shaft (20), there are arranged magnets (22) on the motor shaft (20)... Two or more magnets (22) may be arranged along the longitudinal direction, which are separated by an isolating ring (not shown in Fig. 3)
Implementation Method 3
The rotor includes a motor shaft (20) and a plurality of magnets (22) configured on the shaft (20)... there are arranged magnets (22) on the motor shaft (20)... which are separated by an isolating ring (not shown in Fig. 3)
Implementation Method 4
adjacent to the other end of the motor shaft (20), there are arranged magnets (22) on the motor shaft (20)... Two or more magnets (22) may be arranged along the longitudinal direction
Implementation Method 5
The rotor is supported by a single bearing device (142) which is closer to one end of the motor shaft (120) than to the other end along a longitudinal direction of the motor shaft (120)
Implementation Method 6
Two or more magnets (22) may be arranged along the longitudinal direction, which are separated by an isolating ring (not shown in Fig. 3)
Data Source
Figure 1~2
Figure 3
AI summary
A brushless motor includes a stator (26) having six slots (30), and a rotor having two poles. The rotor is adapted to rotate with respect to the stator. By adopting a 6-slots-2-poles structure, the brushless motor effectively reduces operational noise due to iron loss and unbalanced pull. As a result, the working life of the motor can be improved.