Linear Motor Applications

The linear motor can be considered as a deformation of the rotary motor in terms of its structure. It can be regarded as a rotary motor along its radial section and then flattened and evolved. With the rapid development of automatic control technology and microcomputers, higher requirements are placed on the positioning accuracy of various types of automatic control systems. In this case, a traditional rotary electric machine is combined with a linear motion driven by a set of conversion mechanisms. The devices can no longer meet the requirements of modern control systems. For this reason, many countries in the world are researching, developing and applying linear motors, making the application of linear motors more and more widely.

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 add the rotary motion to a linear motion of the additional device, thus making the system itself greatly simplified structure, weight and size Decline; Second, high positioning accuracy, where linear motion is required, the linear motor can achieve direct transmission, which can eliminate the various positioning errors caused by the intermediate links, so positioning accuracy, such as the use of computer control, you can also Greatly improve the positioning accuracy of the entire system; the third is fast response, high sensitivity and good follow-up. The linear motor is easy to be supported by the magnetic levitation of its mover, so that a certain air gap is always maintained between the mover and the stator without contact, which eliminates contact frictional resistance between the stator and the mover, thereby greatly improving the system. The sensitivity, rapidity and follow-up; Fourth, work is safe and reliable, long life. The linear motor can realize the non-contact transmission force, and the mechanical friction loss is almost zero, so the failure is less and maintenance-free, so the work is safe and reliable, and the service life is long.

Linear motors are mainly used in three aspects: First, they are used in automatic control systems, and they are used in many applications; secondly, they are used as long-term continuous-running drive motors; and third, they are used to provide huge linear motion within a short time and within a short distance. In the device.

High-speed magnetic levitation train The magnetic levitation train is the most typical example of practical application of the linear motor. The United States, Britain, Japan, France, Germany, Canada and other countries are all developing straight-line suspension trains, of which Japan has made the fastest progress.

Linear motor-driven elevator The world's first elevator driven by a linear motor was installed in April 1990 at the Wanshi Building, Toshima District, Tokyo, Japan. The elevator has a load of 600kg, a speed of 105m/min, and a lift height of 22.9m. Since the elevator driven by the linear motor does not have a traction machine, the machine room at the top of the building can be omitted. If the height of a building increases to about 1000 meters, a steel wire rope elevator must be used. This type of elevator is driven by a high-temperature superconducting linear motor. The coil is installed in the hoistway. The car is equipped with a high-performance permanent magnetic material, such as magnetic levitation. Like a train, it uses radio waves or light control technology to control it.

When ultra high-speed motor rotates beyond a certain limit, the motor with rolling bearing will produce sintering and damage. A linear levitation motor (magnetic bearing) has been developed abroad, and the levitation technology makes the motor's mover suspended in the air, eliminating the need for The mechanical contact and frictional resistance between the mover and the stator can reach a rotational speed of 25000 to 100000 r/min or more. Therefore, they are widely used in high-speed motors and high-speed spindle components. For example, the 5-axis controlled, electromagnetic high-speed spindle for multi-process automatic CNC lathes newly developed by Yaskawa Corporation of Japan uses two radial electromagnetic bearings and one axial thrust electromagnetic bearing to withstand the load of the machine tool in any direction. In the middle of the shaft, besides the high-speed motor, there is a tool automatic exchange mechanism that is compatible with multi-process automatic CNC lathes.