Some Problems in Application of Flat Line Motor
time£º2017/5/17 click£º7468
The stator of the flat plate linear motor has strong magnetism itself, so there will be some specific problems in the application. Reasonable solution of these problems will become the key to successful application. The specific application needs to pay attention to the following aspects:
1. Ensure the assembly size between the mover and the stator. The gap between the linear motor and the stator is an important parameter. The small change can cause a great change in the motor performance. The gap will directly affect the output of the linear motor. The small gap may cause damage to the motor due to magnetic adsorption debris. Therefore, the installation must be strictly controlled to ensure the normal use of the motor.
2. Reduce magnetic attraction. The stator of a linear motor has a strong magnetization ability to ferromagnetic materials. The experiments show that the normal magnetic attraction of the permanent magnet stator of a linear motor is about 10 times that of the motor that can provide continuous thrust, and the magnetic suction of the stator has nothing to do with the power of the motor moving element. Magnetic suction exists between the stator and the mover and between the stator and the installer. The arrangement of a single motor usually uses a method parallel to the guide rail of the part. At this time, the magnetic suction greatly increases the bearing capacity of the straight rail, resulting in greater deformation, affecting the machining accuracy of the CNC machine tool, and also increasing the pressure between the guide rail and the slide block., Then the friction force of the sliding block is increased, which may cause thrust fluctuation and affect the dynamic performance of the machine tool. Therefore, it will be an outstanding problem to reasonably reduce the magnetic suction of the motor.
3. Pay attention to anti-magnetic and anti-interference. Since the magnetic field of the linear motor is open, magnetic materials such as metal dust and chip powder are easily absorbed by the magnetic field of the motor, which hinders normal work and even damages the motor. Therefore, magnetic isolation should be performed on the motor. In addition, it is necessary to consider the protection of machine cooling fluids, lubricants, cables, etc., signal line shielding, load interference and system control issues. Since the linear motor drive system does not have an intermediate drive link, interference such as the change of workpiece quality and cutting force directly acts on the motor. At the same time, the edge effect of the linear motor also increases the difficulty of system control. Therefore, the controller needs to have strong anti-interference ability. And stability is good.
4. Need to solve the fever problem. In the operating state of a linear motor, due to the energy loss of the coil work, a large amount of heat will be generated. If the space of the drive part is small, the temperature of the motor moving element will increase dramatically, and the driver is generally located near the machine guide rail. Excessive heat will cause too much temperature change of the machine guide rail, resulting in thermal deformation of the guide rail, which will affect the accuracy of the machine tool. At the same time, the temperature rise of the mover will cause an increase in the resistance value of the internal coil winding. If the system needs to maintain the same output, it will necessarily require a larger current, and the increase in the current will be accompanied by more energy losses, making the temperature higher., thus forming a vicious circle. Therefore, effective cooling measures must be taken to control the temperature within a reasonable range to ensure the normal use of the motor.
Linear motor