Magnetic coupling & permanent magnet
Magnetic coupling & permanent magnetMagnetic coupling belongs to non-contact coupling, which is generally composed of two magnets, and an isolation cover is set in the middle to separate the two magnets. The internal magnet is interconnected with the transmission parts, while the external magnet is effectively connected with the power parts, and the power is transmitted through the NS pole coupling interaction of magnetic field.The magnetic coupling has the function of buffering and absorbing vibration. In addition, it adopts the new magnetic coupling principle to realize the transfer of force and torque between the driving shaft and the driven shaft without direct contact, and can change the dynamic seal into static seal to realize zero leakage.Therefore, it is widely used in situations with special requirements for leakage.
- Application field introduction
Permanent magnet used in magnetic coupling
Coupling is an important part of mechanical transmission,which transmits torque through the coupling between the driving shaft and driven shaft. Magnetic coupling belongs to non-contact coupling, which is generally composed of two magnets, and an isolation cover is set in the middle to separate the two magnets. The internal magnet is interconnected with the transmission parts, while the external magnet is effectively connected with the power parts, and the power is transmitted through the NS pole coupling interaction of magnetic field.The magnetic coupling has the function of buffering and absorbing vibration. In addition, it adopts the new magnetic coupling principle to realize the transfer of force and torque between the driving shaft and the driven shaft without direct contact, and can change the dynamic seal into static seal to realize zero leakage.Therefore, it is widely used in situations with special requirements for leakage. Classification of magnetic couplings: Common magnetic drive includes synchronous drive, hysteresis drive and eddy drive, which are applied in different fields due to their respective characteristics.Synchronous transmission refers to the synchronous output and input. The common synchronous couplings are planar magnetic couplings and coaxial magnetic couplings.
1. Planar magnetic coupling Structure: Two disks of the same diameter, with magnets arranged in the manner of NS poles crossing.When in use, install the two disks on the driving shaft and the driven shaft respectively with a certain air gap between them. Principle: Since the N pole of "A" magnet attracts the S pole of the opposite "B"magnet and repels the N pole on both sides of "B" magnet, the driven axis and the driving axis can keep synchronous rotation within "A" certain torque range.2. Coaxial magnetic coupling
Coaxial magnetic coupling is the most widely used synchronous actuator, the typical application is magnetic pump.
Structure: The coaxial magnetic coupling is composed of an outer rotor, an inner rotor, an isolation cover and a bearing system. The outer circumference part of the inner rotor and the inner circumference part of the outer rotor are equipped with magnets. The magnets are of an even number of poles and arranged in a circular manner according to NS cross mode.Align the working faces of the magnets of the inner and outer rotors, automatic coupling.Isolation cover and bearing system are mainly used in magnetic drive sealing structures.
3. Hysteresis coupling
Hysteresis transmission, is the application of hysteresis principle for transmission mode.Common hysteresis actuators are generally coaxial structures similar to synchronous actuators.The difference is that the internal and external rotors use different magnetic materials.In general, the inner rotor (drive shaft) uses a material with high coercivity and high remanence, such as NdFeb.The outer rotor (driven shaft) is made of a magnetic material with low coercivity, such as Alnico.The magnets on the driving shaft are arranged in a cross arrangement of NS poles.When the load is not greater than the rated torque, the driven shaft and the drive shaft rotate synchronously;When the load exceeds the rating, the inner and outer rotors slip and only the rated torque is transferred to the driven shaft.Excess energy is released in the form of heat in the process of charging and demagnetization of the inner magnet and the outer magnet.
The invention and development of magnetic couplings are closely related to the continuous progress of NdFeB permanent magnet materials.
NdFeB has high magnetic energy, low demand, good machining performance, cutting and drilling, high yield, so it can reduce the size of magnetic couplings, reduce costs, improve efficiency, has been widely used in magnetic drive couplings.
