Study On The Structure And Transmission Characteristics Of Cylindrical Reluctance Permanent Magnetic Gear

Reluctance Permanent Magnetic Gear(RPMG)is a kind of permanent magnetic gear,which follows the principle of minimum reluctance to realize the movement and torque transmission.RPMG has not only the advantages of the common permanent magnetic gear,such as non mechanical contact between the input and output,fundamentally eliminate the problems like friction,mechanical gear wear,noise,vibration and leaking,and it has the overload protection function.RPMG is convenient for manufacturing,low for installation accuracy,and almost maintenance free.Moreover,the permanent magnet used is greatly reduced,so it is not only cost down,resources saving,but also flexible for structure design.RPMG has a wide application prospect.At present,the study on RPMG is lack in the world.In order to resolve the problem RPMG which can not work continuous and stable,the topological structure of Cylindrical Reluctance Permanent Magnetic Gear(CRPMG)was proposed.According to the mutual position relationship of the magnetic poles,the coupling states between the active and stator poles were divided into three modes which are M1,M2 and M0.The action modes between the active and stator poles,the stator and the driven salient pole were analyzed.It was proved that the suggested structure of CRPMG can realize continuous and stable transmission.The calculation formulas of coupling length between active and stator poles,driven salient pole and stator pole were deduced.The static characteristics of the CRPMG were simulated using COMSOL software.It was proved that when the driven rotor is stationary and the active rotor rotates 45 degrees start from the rest position,the output torque is a smooth sine curve.And the output torque is maximum when the rotation angle is 11.25 degrees,which direction is opposite to the rotation direction of active rotor.It is confirmed that the transmission ratio formula of CRPMG is same as the Magnetic Field Modulation Permanent Magnetic Gear.The quasi-dynamic simulation analysis on CRPMG was carried out,and result shows that the input and output torque are stable.The maximum fluctuation of the input and output torque are about 5.6% and less than 3% respectively,so it was proved that CRPMG can work with certain transmission ratio,and transmission velocity and torque continuously and stablely.When the number of active and driven poles is coprime,the torque fluctuation is small,and it has better transmission stability.Whether the active pole width is increase or decrease,it is always working stability with the determined gear ratio.For the width of the driven pole,when it is equal to the gap between poles,the output torque is the largest and torque fluctuation is small.The increase or decrease of the stator width does not affect the smoothness of the output torque.When the width of stator pole reduced,the output torque is higher,but the torque magnification is substantially constant.