Bearingless motors, which do not use ball bearings and plain bearings, can support the shaft with magnetic force in a non-contact state and simultaneously apply a rotational force. On May 28, 2008, MotorSolution (headquarters: Noda City, Chiba Prefecture), a venture company dedicated to the practical use of bearingless motors, was announced. The company will first put into operation an ultrapure water pump motor used in a semiconductor manufacturing plant, bringing sales to about 1 million yen. The company is a venture company founded by the University to produce a "Consequent-Pole" bearingless motor developed by Chiba, who is a professor of electrical and electronic information engineering at the Tokyo University of Science and Technology. The chairman of the board of directors is Professor Chung-Hsien Hsing, who studied together with Professor Chiba's students, and Chiba is a specialist director. Yang Zhongqing is still providing motor drive inverter circuit commissioned the development of Myway Technology Research Chairman. MotorSolution's registered capital is 14 million yen and is provided by people who have worked with Chiba for many years. The new company's goal is to achieve 100 million yen in total sales of the development, manufacture and sales of bearingless motors and the entrusted services of ordinary motors in the third year after its operation. Bearingless motor because there is no need to slide, so has the following features: (1) almost no dust; (2) can rotate at high speed (3) It is able to withstand environments where it is difficult to use lubricants such as very low temperature and vacuum. (4) small noise; (5) basically no friction loss. Therefore, it has always been a hot spot for research. In the past, although there was a precedent of separately installing a magnetic bearing on a motor, as the size of the motor increased, there was a need to supply the floating power at any time irrespective of whether the motor was running or not. In this regard, researchers have developed a way of rotating the shaft while leveraging the flexibility of utilizing the driving mechanism of motor rotation. However, this method generally has the problems of less buoyancy and much lower torque than ordinary motors. Professor Chiba in the study found that alternating polar structure is extremely suitable for bearingless motor structure. Buoyancy can reach more than 30 times the previous bearingless motor, torque is only about 10% lower than the average motor. The structure of the alternating pole type is as follows: the permanent magnets embedded in the rotor are all along the same direction (for example, the N poles are all outward), and an iron core is arranged between the magnets and the magnets. In this way, the magnetic flux from the north pole of the rotor will first enter the opposite stator and then turn around, the stator will enter the core of the rotor (that is, the core becomes the S pole and becomes the "alternating pole"), and finally returns to the S pole of the magnet to form Magnetic circuit. Originally developed by British researchers, the purpose of alternating polar structures was to reduce the number of magnets to reduce the cost of the motor. When the above rotor is used, demagnetization does not occur even if the thickness of the permanent magnet is increased since the magnetic flux of the supporting shaft passes through the iron core of the rotor entirely, and stable shaft supporting force can be produced regardless of the angle of the rotor. No encoder-like angular position sensor and its corresponding high-speed control are required. The application of ultra-pure water pump is a 5-axis control of the bearingless motor. A total of 5 axial directions can be controlled on the radial shaft difference (two dimensional), the axial difference of the motor, and the axial deviation (two dimensional) of the shaft along the radial direction. Motor diameter less than 200mm, remove the protruding part of the shaft, the motor length of less than 200mm. With the highest speed 6000rpm, power 1.2kW, the maximum torque of about 2N · m performance. The axial load is about 100N. In addition, the control of the axis position using? U flow sensor. The difficulty in developing this motor is that it is necessary to expand the gap between the rotor and the stator to 5 mm. Because the pump is a hermetically sealed pump, the coil is partly hermetically sealed and can be used in water, with the impeller and the motor directly in the water. In other words, both the rotor and the stator are covered by the resin, water is supplied between them, and a certain gap needs to be additionally provided to reduce the resistance to water. For this reason, this time, the company set a 2 mm resin layer around the rotor and the stator and provided a 1 mm gap between the resin layers. "The gap of an ordinary motor is about 0.5mm, and the design process is very tough in order to expand this distance ten times and make it work efficiently without bearings" (Professor Chiba). Because when the gap is small, two-dimensional electromagnetic field analysis can be consistent with the experimental results, if you expand the gap, the design needs to use three-dimensional electromagnetic field analysis. Levitronics products are 2-axis controlled and when the water pressure suddenly changes, the shaft tilts, causing the rotor to collide with the stator. This time, MotorSolution will grab ahead of the Levitronics 5-axis control of ultra-pure water pump, in addition to the use of harsh environments, but also will make the best use of the advantages of mechanical bearings to the shaft can be rotated at high speed slow displacement And other special purpose to enter.
Motor Solution's competitor is Levitronics, headquartered in Zurich, Switzerland.