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Selection of Bearing and Mainshaft Bearing Is Crucial to Machine Tool Turntable

Submitted by Tianli on Wed, 09/16/2015 - 18:54

Mainshaft serves as the critical component of machine tool. There are many types of mainshaft such as cylindrical roller. Therefore, its performance can directly affect the machine tool’s running precision, rotate speed, rigidity, temperature rise, noise and other parameters, which in turn affects the machining quality of workpiece. The precision of bearing which is used in mesh machine tool’s mainshaft shall be ISOP5 or above (P5 and P4 are the precision classes of ISO), while the precision of mainshaft bearing which is used in high speed and high precision machine tools such as numerically-controlled machine tool and machining center shall be ISOP4 or above. The mainshaft contains angular contact ball, tapered roller and other types of bearings. For example, if the dimensional precision of deep groove ball is P4 (generally P0 is the highest), it must match with a high-performance mainshaft. How to select rolling mill bearing and turntable bearing which are used in the mainshaft for a machine tool?

    Mainshaft carrier roller

     As the S-type spherical plain thrust bearing goes along with the upgrading of industrial structure, the proportion of numerically-controlled bearing machine tool is rising gradually. Heavy machine tool mainly serves state energy (thermal power, hydropower, nuclear power, wind power generation), shipbuilding, engineering machinery, metallurgy, spaceflight, communication and transportation (railroad, automobile) and other major pillar industries, as well we national key projects. The proportion of high-end numerically-controlled machine tool is also rising constantly. And the machine tool industry represents the trend of the upgrading of industrial structure. National key projects offer a broad market for bearings.

     Machine tool industry is the important part of the bulldozer carrier roller industry. In order to satisfy the machining of the structural components discussed above, the machining workload undertaken by machine tool accounts for about 40%~60% of total manufacturing workload. Modern machine tool is developing toward the direction of “high speed, precision, composition and intelligence”. According to some statistics, the development level of machine tool industry generally marks the industrial development level of a country. The increasing development of modern manufacturing industry brings more and more challenges to the machining ability of machine tool. Therefore, machine tool plays a pivotal role during the development of general machine manufacturing and the entire national economy. At present, new material, new technology and new equipment come forth continuously, thus the customers are more and more demanding on bearing industry.

     Precise Angular Contact Ball

     The contact angle of angular contact pillow block bearing is just the contact angle of the all-purpose paired precise angular contact ball bearing we often refer to. Because the preloaded linear selection has a significant influence on the application of precise angular contact ball bearing, currently, the radial spherical plain bearing of the relatively popular F-series of single fractured outer ring has 15 quill rollers. Generally, preload falls into three categories: light, medium and heavy. It can save a lot of time in installation on some high-rotation-speed and high-precision application occations. At present, several top manufacturers around the world universally provide the preloaded bearing with pre-grinded bearing face. In our model selection at early stage, light preload is more common. Generally, such bearing relieves customers of preload adjustment. But please pay attention to select the preload that is suitable to linear motion.

Among the above bearings, select the most suitable bearing to satisfy customers’ demand that the machine tool product shall not have outer ring flange, because its contact form is point contact. And the precise angular contact ball thrust roller bearing is used most widely. On some superspeed mainshaft application occations, the mixed bearing with ceramic ball (it is generally the Si3N4 or Al2O3) is also used. We all know that the rolling element of angular contact boll is the boll. Compared with traditional full quenching steel ball, ceramic ball’s own characteristics give ceramic ball bearing high rigidity, high rotation speed, high temperature resistance and long service life, thus it can offer higher rotation speed with less heat and higher rotational precision.