Braking Device With Interlaced Magnetic Poles
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Solution Overview
Problem
Conventional braking devices generate significant cogging torque and noise due to varying magnetic flux and gap reluctance, leading to adverse performance impacts, and existing solutions to minimize these issues increase manufacturing complexity and costs.
Innovation Solution
A braking device design featuring a round flywheel with a concave surface, a rotor with magnetic members, and a stator with interlaced large and small magnetic poles, along with a magnetic control unit and a rectifier with Δ-connected and Y-connected three-phase circuits to reduce cogging torque and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If plural permanent magnets and oblique slots are used to minimize cogging torque, then cogging torque and noise are reduced, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent changes the geometric parameters of the magnetic poles by providing different pole arc lengths for N-poles and S-poles. This parameter modification alters the magnetic flux distribution and eliminates the need for complex oblique slots and multiple permanent magnets, thereby reducing device complexity while maintaining low cogging torque
Solution Approach 2:
The patent introduces asymmetry in the magnetic pole design where N-poles and S-poles have different arc lengths. This asymmetric configuration creates a specific magnetic field distribution that reduces cogging torque without requiring the symmetric complex structure of conventional designs with multiple permanent magnets and oblique slots
2Object-generated harmful factors
If plural permanent magnets and oblique slots are used to minimize cogging torque, then cogging torque and noise are reduced, but manufacturing cost increases
Solution Approach 1:
By modifying the pole arc length parameter to be different for N and S poles, the patent achieves noise reduction through optimized magnetic field distribution while using simpler manufacturing processes that do not require precise oblique slot formation or multiple permanent magnet assemblies, thereby reducing manufacturing cost
Solution Approach 2:
The patent extracts and eliminates the need for complex components such as multiple permanent magnets and precisely angled oblique slots. The noise reduction is achieved through the simplified asymmetric pole design alone, removing unnecessary manufacturing steps and reducing overall production cost
3Device complexity
If conventional stator with uniform teeth is used, then device structure is simple, but cogging torque and noise are significant
Solution Approach 1:
The patent applies local quality by making different regions of the stator (N-poles and S-poles) have different properties through different arc lengths. This localized differentiation in pole geometry creates optimized magnetic flux distribution that reduces cogging torque, moving away from uniform tooth design while maintaining relative structural simplicity
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 interlaced magnetic pole arrangement and rectifier configuration significantly reduce cogging torque and noise, with average cogging torque decreased from 86.8 mN-m to 1.21 mN-m, improving operational performance while maintaining structural simplicity and reducing manufacturing costs.
Implementation Method 1
The magnetic control unit is mounted on a lateral of the brace near a rim of the flywheel and is configured to generate magnetism in response to electric currents generated by the coils
Implementation Method 2
The first and second magnetic poles are arranged into a ring in an interlaced manner... The rotor and the stator such configured can generate a deflecting magnetic field that serves to eliminate vibration and the noise caused by cogging torque
Implementation Method 3
a rectifier that is electrically connected to the magnetic control unit and includes a Δ-connected three-phase circuit and a Y-connected three-phase circuit. The Δ-connected three-phase circuit and the Y-connected three-phase circuit independently rectify currents
Data Source
AI summary
A braking device includes a flywheel rotatably mounted on a brace, a circular rotor deposited on the flywheel, and a stator fixed to the brace for combining with the rotor. The stator includes first and second magnetic poles. The first magnetic pole is larger than the second magnetic pole. The first and second magnetic poles are arranged into a ring in an interlaced manner. Each of the first and second magnetic poles has a coil. The braking device has a magnetic control unit mounted on a lateral of the brace near a rim of the flywheel and configured to generate magnetism in response to electric currents generated by the coils, so as to change a rotatory load of the flywheel. With the interlaced arrangement of the large and small magnetic poles, the braking device can have the rotor rotating with less cogging torque, and in turn reduced noise.