What are the functions of slewing ring bearing in CNC vertical lathes?
What are the functions of slewing ring bearing in CNC vertical lathes?
In the CNC vertical lathe equipment, the rotary table is an important component. Its high-speed operation and the requirement of carrying heavy workpieces make it have high-precision operation and anti-overturning moment. This article introduces the function of the single-row cross roller slewing bearing in the CNC vertical lathe, and how to realize its engineering function.
The role of slewing ring bearing in CNC vertical lathes
1. Supporting worktable
The large slewing ring bearings that support the table play a key role in this important mission. In the past, most workbenches used a combination of thrust bearings and radial bearings. This kind of structure is complex and requires more materials. Especially when placing large box parts, the space volume of the entire machine tool is even larger. It is also difficult to install and adjust the preload of the large slewing ring bearing, and it is even more difficult to ensure the centering, and it is difficult to improve the overall precision of the worktable.
2. Runout accuracy
Bearing runout is divided into synchronous runout and asynchronous runout. Synchronous runout can be reduced to a large extent by grinding the table surface, but the influence of asynchronous runout cannot be eliminated, which is mainly determined by the outer diameter tolerance and roundness of the roller. Therefore, the better the asynchronous runout of the bearing is controlled, the smaller the radial and axial runout of the table, that is, the higher the working accuracy. When choosing a bearing brand and accuracy grade, you should not only pay attention to the runout of the bearing device, but should have a deep understanding of the accuracy standards that affect the asynchronous runout of the bearing.
3. Bearing fit
When selecting bearings, it is recommended that the inner ring and the shaft, and the outer ring and the ring gear be tightly fitted. Since the outer ring is a rotating part, the tightening amount should be slightly larger than that of the inner ring, so that the inner ring is pressed by the end cover and moves downward, and adjusted to a certain pre-tightening amount. However, if the inner ring is considered to be a stop part and the inner ring and the shaft are planned as a loose fit, the inner ring may deflect when the inner ring is installed, locked, or the bearing is loaded, that is, deflection occurs. This deflection can cause stress concentrations in the contact area between the rollers and the raceway, leading to severe scoring.
Therefore, more and more design schemes now adopt more compact interspersed roller bearings. The role of slewing bearings in CNC vertical lathes increases the limit speed, and at the same time, the running accuracy and stability are better, and the carrying capacity and rigidity are also stronger. At the same time It can not only save material cost, but also simplify the design scheme. The above is the introduction of the slewing bearing manufacturer.
