Permanent magnet bridge crane

The mechanism of the bridge crane is generally driven and braked by a motor, a reducer, and a brake. The motor speed is high, and the direct output torque is small, so the motor and the working mechanism are generally connected through a reducer. Its function can be summarized as "reducer torque increase", that is, reduce the speed and increase the output torque through the reducer, so as to meet the working requirements of the mechanism. What is a gearless crane now?

There are now two types of European-style cranes on the market: one is a highly integrated electric hoist. Compared with the traditional CD and MD hoist, its layout has been greatly changed. In the European style, the format is usually straight, while the electric hoist is mostly C-shaped. The main structure of the lifting mechanism is higher than the walking mechanism, which greatly saves space. In the European-style general electric hoist adopts a pole-changing motor, which can achieve two-stage hoisting. The deceleration plate is mainly hard tooth surface. The walking wheel is cylindrical, not on the I-steel track, but directly covered under the box girder.

Gearless bridge cranes use permanent magnet brushless motors, which replace the traditional form of motor acceleration and deceleration. The permanent magnet is connected to the rotor of the permanent magnet motor, which can maintain the magnetic field without additional energy, while the magnetic field of the ordinary motor needs to be energized. PMSM can realize low-speed operation, obtain larger torque, and meet the working requirements of the mechanism. However, due to the high price of rare earth and other products, the crane drive mechanism using permanent magnet motors is expensive, which resulted in permanent magnet motors not being widely used in the past. However, with the maturity of technology and the decline in the price of rare earth products, the price of bridge cranes driven by permanent magnet motors is basically the same as that of frequency conversion bridge cranes with traditional motor accelerometers.

The other is the winch structure of a European-style crane. Compared with the traditional lifting crane, its structure is almost unchanged. The main reason is that the accuracy requirements of various transmission parts have been improved, and the use of high-quality accessories to replace the original low-end accessories. If the reducer is changed to a three-pivot hard tooth surface, the drum is made of steel plate, the hook is made of alloy forgings, the pulley is made of double-row rolling pulleys, and the wheels are also made of alloy forging. After improvement, the weight of the whole machine is reduced, the service life is prolonged, the failure rate is low, and the structure is compact.

In fact, permanent magnet bridge cranes have the characteristics of low noise and low noise, especially in low-speed and large-torque mechanisms, long service life and maintenance-free. It can also be combined with more European-style design crane methods on the market to further reduce the weight of the crane and contribute to energy saving and emission reduction.

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