Optimization Design And Transmission Performance Analysis Of Coaxial Magnetic Gear

The traditional mechanical gears transmitted torque by meshing the gear teeth with each other,which led to a series of problems such as loss,vibration,friction and noise during transmission,and needed regular maintenance and replacement,which made it difficult to meet the requirements in some harsh working environments.To solve this series of problems,magnetic gears were born,which work by transmitting torque through the mutual coupling between permanent magnets.Magnetic gears have become a hot topic of concern for researchers in recent years due to their advantages such as no direct contact between teeth during the transmission process,overload protection,and high efficiency.At present,the main purpose of coaxial magnetic gears is to increase torque and change speed by connecting the transmission shaft to the motor;Alternatively,it can be embedded outside a regular permanent magnet motor to form a permanent magnet composite motor,which can be used in fields such as electric vehicles and wind power generation.In previous studies,the main focus was on the relevant theories and structural design of magnetic gears,while there was limited research on optimizing their parameters and transmission performance,which restricted the development and application of magnetic gears.Therefore,this article conducts research on the optimization design and transmission performance analysis of coaxial magnetic gears.Introduced the basic theoretical research of magnetic gears: analyzed the basic structure,working principle,and other aspects of magnetic gears.Theoretical analysis and finite element simulation verification were conducted on the air gap magnetic density of magnetic gears with and without adjustable magnetic rings,and further explained the mechanism of the adjustable magnetic ring.The calculation method for the transmission efficiency and no-load magnetic leakage coefficient of magnetic gears was explained.The important factor whether the magnetic gear can stably output torque is the size of its cogging torque.In order to reduce the cogging torque,this paper uses methods such as modifying the magnetic gear regulating ring and changing the slotting angle of the magnetic gear regulating ring to optimize;The particle swarm optimization algorithm is used to establish the response surface regression model,and the cogging torque of the magnetic gear is optimized using the data obtained from the simulation of Ansys software for many times.The comparison of the cogging torque before and after the optimization verifies that the optimization method can effectively reduce the cogging torque.The relevant theories of magnetic gear transmission performance were explained,and the waveforms of quasi dynamic torque and static torque were obtained through Ansys software.The relationship between the air gap length,axial length,rotor permanent magnet thickness,magnetic ring thickness,rotor yoke thickness,and torque was studied,and the variation pattern of torque with these five parameters was obtained.Analyze the relationship between the noload magnetic leakage coefficient of the magnetic gear and the length of the air gap and the inner rotor permanent magnet,and optimize the no-load magnetic leakage coefficient to obtain a set of optimized structural parameters.Analyze the losses generated by the magnetic gear and obtain specific loss values through Ansys finite element simulation to calculate its transmission efficiency.Finally,a permanent magnet composite motor applied to automotive wheels was proposed,and its structure,transmission performance,air gap magnetic density distribution,static torque,cogging torque,no-load back electromotive force,transmission efficiency,etc.were analyzed.