Research On The Rotary-Linear Motion Magnetic Gear

In several advanced industrial applications,both rotary and linear movements are required. Usually, the mechanical couplings are driven by rotary motors to complete rotary-to-linear motion for these applications. While, several disadvantages cannot be avoided, such as the complex mechanics, great space requirement, frequent mechanical adjustments, high manufacturing and maintenance costs, low reliability, etc. Aiming to all kinds of structure shortcomings of multiple transmissions mentioned above, the thesis focuses on the research of new constructions of magnetic gears in the transmission forms of coaxial and linear to rotation with simple structure, high efficiency, low cost, and noncontact, etc.Firstly, the basic structure, characteristic and operation principle of rotary-linear motion permanent magnet gear are analyzed, based on the principle of the linear-rotating reluctance Motor. It consists of two main parts, one is a translator with linear motion, and the other one is a rotor with rotational motion, which can convert rotation to linear motion through magnetic fields.Two-dimensional (2D) and three-dimensional (3D) Finite Element equivalent model are made for magnet gear by ANSYS.The relation curve between pullout magnetic force and magnetic pole position is obtained through static simulations of the magnetic flux distribution. The Fourier function is set forth for calculating the transient force of the device, which is based on equivalent current method and magnetic equivalent current method. The theoretical results are compared with those of FEM approach with good agreement by MATLAB.To obtain the oscillation rule of the force, the transient performance of the magnetic gear is test quantitatively.In addition, by the method of analysis of model, design size of the magnetic gear and several design parameters impacting gear performance are discussed. Relative curves are plotted about the relationship between the parameters and pullout force, such as the pole-arc coefficient, the thickness of air gap and the comb teeth. Considering of the actual process of the project level, the parameters of the permanent magnetic gear structure is optimized. The magnetic hysteresis loss and eddy-current loss is discussed, based on the design rules of motor.In order to improve the influence of the magnetic fluctuations from the structure, the improvement of the magnetic gear structure is mentioned, including magnetic poles on rotor and the comb teeth in transmission drum. There are two kinds of improvement on magnetic structure, two-layer magnets on rotor are arranged in parallel rows or staggered 30 degree. To increase the number of iron teeth or arrange them as helix can also make the transmission drum move better. The simulations in terms of the improved structure have been done resprctively. The results confirm the optimization.