U-Shaped Magnetic Yoke Motor Torque and Power Optimization
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Solution Overview
Problem
Existing electric toothbrush motors face challenges in providing sufficient torque and magnetic flux due to the design of mountain-shaped iron-core yokes, which results in inadequate driving power and torque transmission.
Innovation Solution
A U-shaped magnetic yoke with coils on its support legs, combined with four centrosymmetrically disposed permanent magnets and a second magnetic yoke, generates alternating magnetic poles to drive a rotary output component, enhancing torque and magnetic flux while minimizing magnetic leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a mountain-shaped iron-core magnet yoke is used in the electric toothbrush motor, then the magnetic flux distribution is achieved, but the torque transmission is insufficient and the driving power is inadequate
Solution Approach 1:
The patent divides the single mountain-shaped iron-core magnet yoke into a U-shaped magnet yoke with two separate support legs (first support leg and second support leg). Each support leg is independently wound with coils and can generate independent magnetic fields. This segmentation allows for improved magnetic flux distribution and enhanced torque transmission capability, directly resolving the insufficient torque problem while maintaining adequate driving power.
Solution Approach 2:
The patent introduces permanent magnets at specific locations (first and second permanent magnets on opposite sides of the rotary output component) to create localized magnetic field enhancements. This local quality improvement ensures that magnetic flux is concentrated where needed for optimal torque generation, addressing the inadequate driving power issue while maintaining balanced magnetic flux distribution across the motor structure.
2Force
If the magnetic flux of the middle support of the mountain-shaped iron-core yoke is large, then the magnetic circuit is established, but the magnetic flux of the two ends is small resulting in small permanent magnet force
Solution Approach 1:
By segmenting the single support structure into two separate support legs with independent coil windings, the patent enables independent control and optimization of magnetic flux at each location. This allows sufficient magnetic flux to be delivered to both end regions where permanent magnets are positioned, ensuring strong permanent magnet force without compromising the overall magnetic circuit integrity.
3Force
If spring resonance is used to guarantee torque transmission, then sufficient torque is achieved, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the spring resonance mechanism from the torque transmission system. Instead of relying on complex spring-based resonance to guarantee torque transmission, the design achieves sufficient torque through the improved U-shaped magnet yoke structure with optimized magnetic flux distribution, thereby reducing device complexity while maintaining effective torque transmission.
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 increases torque and reduces driving power requirements, providing a more efficient reciprocating rotational motion for the electric toothbrush, ensuring effective torque transmission and ergonomic convenience.
Implementation Method 1
An electric motor is an electromagnetic device that converts electrical energy into mechanical energy based on the law of electromagnetic induction
Implementation Method 2
the permanent magnet drives the rotary output component to reciprocatively rotate under the action of a coil mounted on the mountain-shaped iron-core yoke
Data Source
AI summary
Provided are an electric toothbrush and its drive motor, which comprises a U-shaped magnetic yoke, a rotary output component, a second magnetic yoke and four permanent magnets. The two support legs of the U-shaped yoke are respectively wound with coils, enabling the two leg end faces to generate alternating magnetic poles under the control of circuit. The four permanent magnets are centrosymmetrically disposed about a rotatory central line, the first and the fourth magnet are of the same polarity, the second and the third magnet are of the same polarity; the first and the second magnet are of the opposite polarity, disposed corresponding to the first leg; the third and the fourth magnet are of the opposite polarity, disposed corresponding to the second leg. Under the control of circuit, the driving permanent magnets drive the second yoke and the rotary output component to reciprocatively rotate about the rotatory central line.