双排球式回转支承有三个座圈，钢球和隔离块可直接排入上下滚道，根据受力状况，安排 了上下两排直径不同的钢球。这种形式装配很方便，上下圆弧滚道路的承载角都为90度。能承受很大的轴向力和倾翻力矩。当径向力大于0.1倍的轴向力时，滚道须特殊设计。双排异径球式回转支承的轴向，径向尺寸都比较大，结构紧固。特别适用于要求中等以上直径的塔式起重机，汽车起重机等装卸机械上。

The double volleyball type slewing support has three seat rings, and the steel balls and isolation blocks can be directly arranged into the upper and lower raceways. According to the force conditions, two rows of steel balls with different diameters are arranged on the upper and lower raceways. This form of assembly is very convenient, with a bearing angle of 90 degrees for both the upper and lower arc rolling roads. Capable of withstanding significant axial forces and overturning moments. When the radial force is greater than 0.1 times the axial force, the raceway must be specially designed. The axial and radial dimensions of the double row differential diameter ball type rotary bearing are relatively large, and the structure is tight. Especially suitable for loading and unloading machinery such as tower cranes and truck cranes that require a diameter of medium or above.