Double row ball slewing bearing is mainly used for wind turbine electrical equipment and concrete transportation pump trucks. In wind power equipment, the bearing is installed at the root of the propeller to act as a side propeller. The clearance is required to be zero or negative, and the starting friction torque is very large and with high rotation accuracy. In terms of its own characteristics, this bearing has a compact structure, which effectively saves the center diameter of the inner and outer ring mounting holes and improves the load-bearing capacity.
1. Wind turbine
The material of the yaw and pitch bearing ring is 42CrMo, the heat treatment adopts the overall quenching and tempering treatment, and the raceway surface is quenched. The force of yaw and pitch bearings is complex, and the impact and vibration are relatively large. Therefore, the bearing is required to withstand both impact and large load. The life of the wind turbine main engine is 20 years, and the cost of bearing installation is relatively high. Therefore, the life of the yaw and pitch bearings must also reach 20 years. The hardness of the bearing ring matrix is 240-280HB, which can withstand impact without plastic deformation. At the same time, the surface quenching hardness of the raceway reaches 55-62HRC, which can increase the contact fatigue life and ensure the long life of the bearing.
2. Marine cranes
Marine cranes generally use double-row reducing balls, four-point contact balls, and three-row roller internal gear slewing bearings. Depending on the load capacity, three-row roller slewing bearings are usually used for heavy-duty cranes. Contact ball slewing and double-row reducing ball slewing bearings are used for light cranes. Since cranes work in an environment of -20°C—+45°C, this type of bearing requires high mechanical properties of the material.
3. Offshore platform cranes
According to different load capacity requirements, offshore platform cranes usually use four-point contact ball turntable and three-row roller internal gear turntable bearings. The slewing bearing used on the offshore platform crane has special material requirements. The mechanical properties of the material must ensure the safety factor under the limit load. The Charpy impact test of the forging sample can reach the average value of 42J@-20°C or 27J@-40 °C. Finished bearings must be certified by classification societies.
4. Port mobile cranes
Port cranes usually use internal or external toothed three-row roller slewing bearings with a diameter of 4 meters to withstand high overturning moments.
The turntable bearings used for stacker-reclaimer usually adopt ball-column combined type, three-row roller type and cross roller type, and the diameter is mostly over 3 meters. Due to the harsh working environment and heavy dust, this type of bearing has the characteristics of high load carrying capacity, long life and good sealing performance.
6. Ferris wheel
The four-point contact ball slewing bearing used on the Ferris wheel, the outer diameter is 4100mm, the thickness is 85mm
7. Ship unloaders
The slewing bearings used in ship unloaders usually adopt the structure of three-row rollers with external teeth, with a diameter of about 4 meters.
8. Tower crane
The slewing bearing for the tower crane usually adopts a small size four-point contact ball slewing bearing or a double-row ball slewing table with a diameter of no more than 2 meters.
Tianda Short-wave antennas generally use three-row roller structure slewing bearings, which rotate slowly.
10. Shield tunneling machine
The diameter of the slewing bearing for shield tunneling machine ranges from 2.5 meters to 6 meters, and some have larger diameters. This type of bearing works under very harsh conditions, with large bearing loads, strong corrosion resistance and short life. .
11. Ladle turntable
The turntable bearing for ladle turntable usually adopts three-row roller structure. Because it works under harsh conditions with dust and high temperature, it has high requirements for retainers, grease and sealing strips.
12. Construction machinery
The slewing bearing for construction machinery usually adopts small size four-point contact ball slewing bearing with a diameter of no more than 2 meters.