Design And Simulation Of A Rotary-linear Permanent Magnet Motor

In recent years, scholars in and abroad have carried out some research works on a kind of rotary-linear motor which can rotate and move in straight line synchronously. Moreover, what scholars had mainly concerned on was induction rotary-linear motor. However, there is no systematic exposition for this two-degree-of-freedom motor until now. As there are widely potential applications of the rotary-linear motor in processing and manufacturing areas, it is necessary to research this two-degree-of-freedom motor.When permanent magnet motor has the advantage of compact form, high efficiency and small size, the paper designed a rotary-linear permanent magnet electromotor from the perspective of motor ontology design. Meanwhile, a finite element software was introduced to help to analysis the characteristics of the magnet flux. The main research results of this paper are as following:1,Based on current researches, this paper designed a cylinder-type rotary-linear permanent magnet motor. The principle and the basic structure of this electromotor were established: two sets of windings of which one is for rotation and the other is for linear motion are pressed in the stator slot, the magnetic circuit of the motor is protruding surface structure and the permanent magnetic poles are staggered distributed in space which contributes to the formation of electromagnetic force in the interaction of two kinds of air gap magnetic field, and then the length of the rotor is longer than stator length in axial direction.2,In this paper, some parameters were designed or selected referred to the current design methods of permanent magnet electromotor. What had design include rated data and technical requirements, the pole number, gap length, magnet thickness, two sets of stator windings and the stator slot. After the design, the maximum torque was calculated according to the designed data and the torque formula of the rotary-linear motor. The maximum torque value and tractive force indicate that the design parameters are reasonable and the torque and force can accord with the requirements presented.3,In order to investigate the magnetic flux distribution of the rotary-linear permanent magnet motor and analysis the characteristics of torque and force after, this paper made finite element model for this new electromotor. Because the number of the gridding was too much and the model was symmetrical, finite element model of a quarter was built finally. In the simulation, the models in three kinds of condition including no-load, applying torque current and applying force current were solved, and the magnetic flux density was imported and plotted in the post-processing. The inside magnetic field was complex for there were both rotating magnetic field and travelling magnetic field within the motor. As a result, the boundary of the axial ends was too complex to make certain. So parallel boundary condition and vertical boundary condition were applied to the motor and solved separately to distinguish.