As an important part of mechanical equipment industry, machine tool industry plays an important role in the development of the whole national economy.With deepening of China's industrial structure, the numerical control machine tools and heavy machine tools has become the important pillar of national industry, will also promote the vigorous development of the bearing industry, in the general machinery manufacturing, machine tool processing workload accounted for about 40% of the total manufacturing workload / 60%, therefore, the development of machine tool industry level is often a symbol of national industrial development level.With the continuous development of modern manufacturing industry, customers put forward higher and higher requirements for industrial machine tools.At present, the continuous emergence of new materials, new technology and new equipment has brought many challenges to the processing capacity of machine tools.In order to meet the processing requirements of the structural parts, modern machine tools are developing towards the direction of "high speed, precision, composite, intelligent".
So how do you choose mechanical bearings?Here are two types of guidance:
Machine spindle bearing
As a key part of the machine tool, the performance of the spindle directly affects the machine tool's rotation precision, speed, stiffness, temperature rise and noise, and then affects the processing quality of the workpiece, such as the dimensional precision of the parts.Surface roughness and other indicators.Therefore, in order to maintain good machine processing capacity, must be equipped with high performance bearing. Precision machine tool spindle bearing should be ISO 5 or above (P5 or P4 is the accuracy level of the ISO, usually from low to high as P0, P6, P5, P4, P2), for high speed, high precision machine tools, such as CNC machine tools and machining center spindle bearing, you need to choose the ISO 4 or higher accuracy;Spindle bearings include and other types.
Precision angular contact ball bearings
Of the bearings mentioned above, the precision angular contact ball bearings are the most widely used. We all know that the drum is a ball, because it is a point contact (different from the linear contact of roller bearings), it provides higher speed, less heat generation, and higher rotation accuracy.In some ultra-high speed spindle applications, hybrid bearings with ceramic balls (typically Si3N4 or Al2O3) are also used.Compared with the traditional fully hardened steel ball, the ceramic ball bearing itself has the characteristics of large stiffness, fast speed, high temperature resistance, long life and so on, which meets the requirements of high-end users for machine tool bearing products.
As for the contact Angle of angular contact ball bearing, the contact Angle of 15 and 25 degrees is generally used at present.Generally, the contact Angle of 15 degrees has higher rotational speed performance, while the contact Angle of 25 degrees has higher axial bearing capacity.Because the choice of preload has a great impact on the application of precision, such as in the case of high load and high stiffness, usually choose medium or heavy bearing.For some high-speed, high-precision applications, in the early selection of bearings, it is necessary to pay attention to the selection of appropriate preload, generally lighter preload is more common.