Motor thermal sleeve

Motor thermal sleeve

  The motor manufacturing industry provides power generation equipment for the power industry, as well as power machinery for various other industries, transportation and agricultural production. The motor assembly process is the main process of motor production. In the motor stator and rotor assembly, the hot-sleeve process is widely used in the maintenance and installation process of the motor factory, such as the assembly of the rotor and impeller of the steam turbine, the assembly of the motor stator, the assembly of the coupling and the assembly of the bearing.

Hot sleeve process

  The full name of the hot sleeve is the heating device. The hot sleeve process is completed at a high temperature. It is necessary to ensure that the temperature during the sleeve is higher than the temperature of the workpiece, that is, the hot sleeve process is suitable for the connection of the workpiece at a lower temperature. In the hot sleeve matching of the rotor of small and medium-sized motors, generally, the cast aluminum of the rotor is used to reheat the rotor for hot sleeve. The hot sleeve process can save cold pressing equipment. At the same time, the combination of the rotor core and the shaft is more reliable. Because the thermal sleeve uses the principle of thermal expansion and contraction to heat and expand the containing member and then cool it, the hole of the containing member shrinks and wraps the contained member, which ensures sufficient interference and high reliability. In order to make the hot-sleeve process go smoothly, it is necessary to determine the heating temperature required for the cast aluminum rotor to be loosely sleeved on the shaft. Generally, the jacket should be heated first during the hot-sleeve process. The heating method is based on the material and size of the assembly workpiece. , Work environment, and the amount of interference. The hot-sleeve processing technology must ensure safety and the suit cannot be jammed, causing economic losses and prolonged production cycles; it must also ensure that the rotor insulation and parts are not damaged or reduce the service life or even damage, and at the same time reduce the process cost, so the hot-sleeve technology It has always been one of the key technologies and difficulties in motor manufacturing.

Motor electromagnetic induction heating jacket technology

  With the gradual improvement of people's awareness of environmental protection and energy conservation, high-efficiency and environmentally-friendly high-tech is more and more popular. High-efficiency and energy-saving motor electromagnetic induction heating jacket technology is more and more widely used in the motor manufacturing production process, related research materials are also endless, and enterprises have also obtained corresponding economic benefits from it. Motor electromagnetic induction heating jacket technology is a new technology with high efficiency and energy saving in motor manufacturing.

  The basic principle of induction heating is to use the law of electromagnetic induction and the principle of Joule heating effect. When alternating current passes through the coil, an alternating magnetic field is generated. If a charged conductor is placed in this coil, eddy currents will be induced. Since the electrical conductor is made of resistive material and the resistance value is small, the generated eddy current is very large. When the eddy current passes through, it will generate Joule heat, which will increase the temperature of the surrounding environment. The induction heat treatment equipment can heat the work piece of electrical conductor material to a very high temperature in a short time.

  Because the electromagnetic induction heating sleeve workpiece and the induction coil of the motor transfer energy through the magnetic field, reducing the loss of heat energy transfer through the air, the electromagnetic induction heating sleeve process has the advantages of low heat loss and high thermal efficiency, and the thermal efficiency is very high, reaching 85%. The above is 2-3 times higher than the resistance wire heating method". With the reduction of heat loss, the heat radiated into the air is also greatly reduced, which greatly reduces the ambient temperature", which reflects the concept of energy saving and high efficiency.

  Electromagnetic induction heating devices for motors generally use coils and semiconductor devices, which have a long service life and greatly reduce maintenance costs. Electromagnetic induction heating sleeve workpiece and motor stator and rotor resistance are very low, very low induced electromotive force can generate strong induced current, and its thermal efficiency is very high, so the heating sleeve workpiece heats up very quickly. Compared with the heating time of the resistance wire, the temperature rise time is greatly shortened, which greatly improves the production efficiency.

  The motor electromagnetic induction heating jacket technology has the advantages of high thermal efficiency, fast temperature rise, and easy automation. It is currently the most energy-saving and environmentally friendly heat treatment process. The comprehensive promotion of electromagnetic induction heating technology is an inevitable trend to transform my country's traditional industries.

Current status and solutions of electromagnetic induction heating jacket technology

  At present, the motor assembly electromagnetic induction heating jacket technology has replaced the high energy consumption and low efficiency resistance furnace heating technology and the infrared halogen lamp heating technology. However, during the use of the electromagnetic induction heating jacket technology of the motor, when the batches of the workpieces are different, the size difference causes differences in the electromagnetic induction power percentage and heating time parameter settings. Improper parameter settings will cause the workpiece to be heated to a temperature that is too high or too low. , The heating temperature is too high to cause the surface of the product shell to burn, and unnecessary high temperature also increases the energy consumption; the uneven heating temperature causes the jacket to fail and the heating jacket fails. In this way, secondary heating is necessary or the product may be scrapped, which greatly affects the production quality and production schedule of the motor. In this situation, in order to reduce the scrap rate of batch products, companies can only do a lot of experiments on each batch of products before production, and measure a lot of data: product material, wall thickness, structure (is it uniform wall thickness or step changes) Wall thickness), the length of the silicon steel sheet of the product, find out the maximum tolerance and minimum tolerance, find a compromise point of electromagnetic induction heating parameters, and conduct experiments one by one to see if the hot sleeve process is feasible, until it can meet the process production requirements of the maximum tolerance product So far, then mass production of this batch is carried out according to the experimental results. Under this situation, the production of electromagnetic induction heating jackets for motors is not suitable for heating with many varieties and small batches. It is only suitable for heating with small varieties and large batches. Moreover, a large number of experiments before mass production also lead to the scrapping of some products. At the same time, the experiment The staff also wasted a lot of time and energy.