Study On Characteristic And Design Of Permanent Magnet Roller For Belt Conveyor

The belt conveyor is widely used in various fields due to its simple structure,wide variety of materials to be transported and strong conveying capacity.It has become the main transport equipment for bulk materials.In order to meet the production needs and respond to the call for national energy saving,long distance,large volume and energy saving are the inevitable trends in the development of belt conveyor.With the development of large-scale belt conveyor,problems such as large rotational resistance and large energy consumption caused by the roller have become more prominent.Studies have shown that about 70% of the energy consumption in the conveyor is related to the roller,while the frictional resistance of the mechanical bearing accounts for 80%-90% of the rotational resistance of the roller.Moreover,due to the instability of the conveying capacity,the belt conveyor is often in a light load or no-load state,causing a lot of energy waste.Therefore,the friction problem of the roller is solved,the conveying amount of the belt conveyor is detected in real time,and the belt speed is adjusted reasonably,which can reduce energy consumption and improve energy utilization effectively,thereby achieving the purpose of energy saving.In this paper,the permanent magnet bearing,which has the advantages of low energy consumption?no mechanical contact and simple structure,was applied in the roller.Firstly,a permanent magnet roller was designed,supported by radial permanent magnetic bearing,but the axial force was supported by thrust ball bearing.The load of the permanent magnet roller was analyzed and calculated.The mathematical model of single pair of permanent magnet bearing was established combined with the equivalent magnetic charge method.The finite element method was used to optimize the structural parameters of the permanent magnet bearings,and the results of equivalent magnetic charge method and finite element method were compared and analyzed to indicate the reliability of finite element analysis.The supporting characteristic of the permanent magnet bearing was analyzed by the finite element method,and combined with its supporting characteristic,the optimal configuration of the inner and outer magnetic rings in the permanent magnet roller was determined.Secondly,the axial forces of the permanent magnet bearing,with different axial relative positions of the inner and outer magnetic rings,were tested by experiment.Compared with the results of simulation and experiment,to verify the accuracy of the finite element simulation analysis.The rotational resistance of the permanent magnet roller was studied by coal standard method.And the changes of the rotational resistance were analyzed,for the case of whether or not a seal was included and different axial relative positions of the inner and outer magnetic rings.The results showed that adjusting the axial relative position of the magnetic rings could reduce the rotational resistance of the roller,the seal and its installation accuracy also could affect the rotational resistance.Compared the rotational resistance of the same type of mechanical roller,it showed that the rotational resistance of the permanent magnet roller was smaller than the mechanical roller.It showed that replacing the mechanical roller with the permanent magnet roller could reduce the rotation resistance and reduce the energy consumption of the conveyor system.Finally,combined with non-contact characteristic and supporting characteristic of the permanent magnet roller,a method for detecting the conveying capacity of the belt conveyor by detecting the radial offset of the permanent magnet roller was proposed.The relationship between the load and the radial offset of the permanent magnet roller was obtained by experiment test,which provided the basis for the detection of the conveying capacity.