DICI Linear motor can be regarded as a kind of structural deformation of rotating motor, which can be regarded as a rotating motor that is split along its radial direction and then flattened. With the rapid development of automatic control technology and microcomputers, higher requirements have been put forward for the positioning accuracy of various automatic control systems. In this case, the linear motion drive device composed of traditional rotating motors and a set of transformation mechanisms is far from meeting the requirements of modern control systems. Therefore, many countries in the world are studying, developing and applying linear motors, It makes the application of linear motor more and more extensive.
DICI Compared with the rotary motor, the linear motor has the following characteristics: First, the structure is simple. Because the linear motor does not need to change the rotary motion into an additional device of linear motion, the structure of the system itself is greatly simplified, and the weight and volume are greatly reduced; Second, the positioning accuracy is high. Where linear motion is required, the linear motor can realize direct transmission, thus eliminating various positioning errors caused by intermediate links. Therefore, the positioning accuracy is high. If microcomputer control is adopted, the positioning accuracy of the whole system can be greatly improved; Third, the reaction speed is fast, the sensitivity is high, and the follow-up is good. Linear motor is easy to use magnetic suspension to support its mover, so that there is always a certain air gap between the mover and the stator without contact, which eliminates the contact friction resistance between the stator and the mover, thus greatly improving the sensitivity, rapidity and follow-up of the system; Fourth, the work is safe and reliable, and the service life is long. The linear motor can realize non-contact transmission of force, and the mechanical friction loss is almost zero, so there are few failures and maintenance free, so the work is safe and reliable, and the service life is long.
Linear motor is mainly used in three aspects: First, it is used in automatic control systems, which are more common; Second, as a long-term continuous operation of the drive motor; Third, it is applied to devices that need to provide huge linear motion energy in a short time and a short distance.
High speed magnetic levitation train The magnetic levitation train is the most typical example of the practical application of linear motor. The United States, Britain, Japan, France, Germany, Canada and other countries are developing linear levitation trains, of which Japan has the fastest progress.
Elevator driven by linear motor The first elevator driven by linear motor in the world was installed in Wanshi Building, Toyoda District, Tokyo, Japan in April 1990. The load of the elevator is 600kg, the speed is 105m/min, and the lifting height is 22.9m. Since the elevator driven by linear motor has no traction unit, the machine room on the top of the building can be omitted. If the height of the building increases to about 1000 meters, the elevator without wire rope must be used. This elevator is driven by a linear motor with high-temperature superconducting technology. The coil is installed in the shaft, and the car is equipped with high-performance permanent magnetic materials. Like the maglev train, it is controlled by radio waves or optical control technology.
When the super high speed motor rotates beyond a certain limit, the motor with rolling bearing will be sintered and damaged. A linear suspension motor (electromagnetic bearing) has been developed abroad. The suspension technology is used to suspend the motor rotor in the air, eliminating the mechanical contact and friction resistance between the rotor and the stator, and its speed can reach more than 25000~100000r/min, Therefore, it is widely used in high-speed motors and high-speed spindle components. For example, the 5-axis controllable electromagnetic high-speed spindle for multi process automatic CNC lathe newly developed by Yaskawa Company of Japan adopts two radial magnetic bearings and one axial thrust magnetic bearing, which can bear the load of the machine tool in any direction. In the middle of the shaft, in addition to the high-speed motor, there is also an automatic tool exchange mechanism suitable for the multi process automatic CNC lathe.
