How does the permanent magnetic coupling achieve leakage-free and efficient transmission?

In the field of industrial transmission, the coupling is a key component connecting the prime mover and the working machine, and its performance directly affects the stability and reliability of the entire transmission system. Traditional couplings, such as rigid couplings and flexible couplings, often have problems such as difficult sealing, easy leakage, and large vibration while transmitting torque. The emergence of permanent magnetic couplings provides new ideas and methods to solve these problems. So, how does the permanent magnetic coupling achieve leakage-free transmission and efficient operation?

The permanent magnetic coupling is a new type of coupling that connects the prime mover and the working machine through the magnetic force of the permanent magnet. It does not require direct mechanical connection, but uses the interaction between rare earth permanent magnets and relies on the magnetic lines of force generated between two groups of permanent magnets to connect with each other. Since the magnetic field can penetrate materials and a certain spatial distance, it can transmit power.

Specifically, the permanent magnetic coupling is usually composed of an outer rotor, an inner rotor and an isolation sleeve. Magnets are installed on the outer circumference of the inner rotor and the inner circumference of the outer rotor. The magnets have an even number of poles and are arranged circumferentially in a NS cross pattern. Align the working surfaces of the magnets of the inner and outer rotors, that is, automatic coupling. When the prime mover drives the inner rotor to rotate, the magnetic field generated by the permanent magnet on the inner rotor is transmitted to the permanent magnet on the outer rotor through the isolation sleeve, thereby driving the outer rotor to rotate synchronously and realizing power transmission.

The permanent magnetic disk is the core part of the permanent magnetic coupling and is composed of high-performance permanent magnetic materials, such as rare earth neodymium iron boron and rare earth cobalt permanent magnetic materials. After special treatment, these permanent magnetic materials have the characteristics of high magnetic energy product, high stability, and low attenuation. The permanent magnetic disk transmits torque through the interaction force of magnetic force, and its performance directly affects the transmission capacity and stability of the permanent magnetic coupling.

The material of the conductor disk is usually metal copper, which has good thermal conductivity and electrical conductivity. In the permanent magnetic coupling, the conductor disk mainly plays the role of conducting magnetic field and current, and cooperates with the permanent magnetic disk to realize power transmission.

The input shaft is the input part of the permanent magnetic coupling, and the output shaft is the output part. They are usually made of carbon steel or alloy steel. The function of the input shaft is to connect the active shaft and the conductor disk of the permanent magnetic coupling to transmit torque, and the function of the output shaft is to connect the output shaft and the permanent magnetic disk of the permanent magnetic coupling to transmit torque.

The permanent magnetic coupling realizes the transformation of dynamic seal into static seal, which completely solves the leakage problem of dynamic seal in some mechanical devices. Since there is no direct connection between the two half couplings of the permanent magnetic coupling, but through magnetic lines of force, there is no need for shaft sealing, and the variable seal is static seal, which can achieve leakage-free or absolute sealing. This feature makes permanent magnetic couplings widely used in sealed transmission machinery in chemical, electroplating, papermaking, pharmaceutical, food, vacuum and other industries.

The permanent magnetic coupling has certain buffering and vibration reduction performance, which can reduce vibration and impact in the transmission system. At the same time, it also has good axial (Ax), radial (Ay), and angular (Aα) compensation performance, which can adapt to the relative displacement between the two shafts and ensure the stability of transmission.

Permanent magnetic coupling can limit torque transmission and realize overload protection. When the load in the transmission system exceeds the set value, the permanent magnetic coupling will automatically slip to avoid motor damage and play the role of a safety coupling.

The permanent magnetic coupling has a simple structure, does not require lubrication, is easy to assemble and disassemble, and is easy to maintain. It does not require working medium, does not have leakage problems, does not pollute the environment, and reduces the cost of use and the difficulty of maintenance.

The permanent magnetic coupling has a high transmission efficiency and can efficiently transmit the power of the prime mover to the working machine. It does not pollute the power grid, does not generate harmonics, and ensures the stable operation of the power system.

According to different application requirements, permanent magnetic couplings can be divided into standard permanent magnetic couplings, torque-limited permanent magnetic couplings, clutch-type permanent magnetic couplings, and synchronous permanent magnetic couplings. Standard permanent magnetic coupling is designed for the equipment with the largest transmission torque, suitable for large crushers, coal crushers, belt conveyors, water pumps and other equipment; torque-limited permanent magnetic coupling is used in equipment with limited torque, and can limit the maximum load torque to protect the motor under high starting inertia/torque load, pulse and periodic vibration load; clutch permanent magnetic coupling can achieve heavy-load start and no-load start, suitable for belt conveyors, air preheaters and other equipment; synchronous permanent magnetic coupling is suitable for equipment with constant torque, low speed and high torque, and high inertia speed synchronization.

Pump equipment: Permanent magnetic coupling is still a new type of coupling in China. It is currently only used in centrifugal pumps and is called magnetic drive centrifugal pump, referred to as magnetic pump. It uses the good sealing performance of permanent magnetic coupling to solve the shortcomings of running, bubbling, dripping and leakage that are difficult to solve with mechanical seals. In addition, permanent magnetic coupling can also be applied to various types of pumps such as screw pumps and gear pumps to achieve sealless pumps and prevent damage caused by corrosive liquid media through shaft seals.
Mixer: In the transmission of the mixer, the permanent magnetic coupling can prevent the leakage of harmful substances, protect the environment and production safety.
Electric diving equipment: Permanent magnetic coupling can be applied to electric diving equipment, such as submersible pumps, to improve the reliability and service life of the equipment.
Vacuum technology and deep-sea oil drilling rigs: Permanent magnetic couplings can also be applied to various vacuum technologies and deep-sea oil drilling rigs to meet their transmission needs in special environments.