In the vertical turning equipment, the rotary table is one of the core structures that reflects the overall functions of the machine tool and completes the processing accuracy of the workpiece. We require it to work at high speed and withstand heavier workpieces, have accurate running accuracy and very high anti-overturning moment ability, and the large turntable bearing supporting the workbench is the key to accomplish this important mission. Previously, most of the domestic workbenches used thrust bearings and radial bearings in cooperation. This arrangement method has a complicated structure and uses more materials. Especially when large box parts are installed, the space of the entire machine tool is larger. It is also difficult to adjust the device and preload of large slewing bearings, the alignment is even more difficult to guarantee, and it is difficult to improve the overall accuracy of the workbench.
Therefore, more plans are now beginning to choose interleaved roller bearings with a more compact structure, which not only saves data costs, but also simplifies the planning scheme, higher limit speed, better operation accuracy and stability, and stronger load-bearing ability and rigidity. This article introduces Ru'an's use of interspersed roller bearings on vertical lathes to complete its perfect engineering function.
1. Runout accuracy
Bearing run-out can be divided into synchronous run-out and asynchronous run-out. The influence of synchronous run-out on the overall run-out of the worktable can be greatly reduced by grinding the work surface, but the impact of asynchronous run-out cannot be eliminated in this link. Mainly determined by the roller outer diameter tolerance and roundness. Therefore, the better the asynchronous runout control of the bearing, the smaller the final radial and axial runout of the worktable, that is, the higher the working accuracy. When selecting bearing brands and accuracy grades, it is recommended not to focus only on the beating of the bearing device, but to deepen the understanding of the accuracy standards that affect the asynchronous beating of the bearing.
2. Bearing cooperation
When selecting bearings, it is recommended that the inner ring and the shaft, and the outer ring and the gear ring be in close cooperation. Since the outer ring is a rotating part, the tight fitting amount should be slightly larger. The inner ring will be pressed down by the end cap and adjusted to a certain pre-tightening amount, so the tight fitting amount should be slightly smaller. However, if the inner ring is considered to be the stopping part, and the inner ring and the shaft are planned to be loose, there is a radial gap between the inner ring and the shaft, it is possible that the inner ring may be deflected when the inner ring of the device, the inner ring is locked, or the bearing is loaded. Oblique, migraine occurs. This kind of misalignment will cause stress concentration in the gap between the contact area of the roller and the raceway, resulting in serious scratches, craters and spalling, and end the life of the bearing earlier.
