CNC milling machine spindle bearing assembly have? Knowledge is important - bearing rigidity

On the nc milling machine, CNC lathe spindle is one of the main machine tool rigidity and precision parts, main shaft quality depends on the layout of the internal bearing structure and installation method. For everyone to share, below the main shaft bearing arrangement and configuration and adjustment methods. A, angular contact ball bearing in the spindle configuration and preloaded on 1, angular contact ball bearings are usually decorate a form. There are three kinds of angular contact ball bearing arrangement: ( 1) Back-to-back arrangement, already wide-brimmed relatively. ( 2) Face-to-face arrangement, that is, relatively narrow side. ( 3) After synthetic back-to-back arrangement in pairs, i. e. , tied for pairs back to back. Back-to-back arrangement bearing of the line of contact Angle along the rotation axis diffusion, therefore, increases the radial and axial rigidity, resistance to deformation ability, is the most commonly used a form of bearing arrangement. 2, angular contact ball bearing preloaded. In order to make the configuration of angular contact ball bearing spindle improve accuracy, increase rigidity, must add to bearing the load. Advance of loading to slightly greater than or equal to work load. More commonly used is to use bearing liner width difference between inner and outer ring, under the action of nut, for bearing preload. For general equipment, as long as the main shaft flexible operation can be ensured and the temperature is low, and can satisfy the working need of rigid suitable for assembly. Repair, usually is based on the original liner width difference adjust appropriately. For high precision rotary spindle, the commonly used method is in the liner between the bearing inner and outer ring, inner bushing can be slightly inclined one, and then with both hands thumb and forefinger to eliminate all two bearing clearance, the other with a middle finger into the bearing hole, strike had partial lining set, check whether the resistance is similar to the bushing. Second, tapered roller bearing on the spindle configuration and adjust 1, tapered roller bearing in the spindle on the common decorate a form. Tapered roller bearing on the spindle usually has four kind of decorate a form: (1) before and after each put a bearing spindle structure. (2) the end of installation of two bearings in the form of back to back, put a cylindrical roller bearing the back-end. (3) form front to back to back to install two bearing spindle. The back-end to install a bearing, and a few spring pin its outer ring to eliminate the gap. Two bearings (4) end of installation, axial fixation. Backend to install two bearings, the outer ring axial movement is allowed. 2, tapered roller bearing adjustment in the assembly (1) strictly controlling bearing inner hole and shaft. Must make the bearing inner ring at the journal with neither loose and flexible to move along the axial direction. For inner and outer ring assembly, the shaft and bearing hole with both hands thumb just can push to cooperate as appropriate. (2) appropriate adjusting nut to make bearing preload, has the corresponding clearance with spindle maximum speed. Adjust, can tighten nut, while the spindle rotation. Have a little resistance make the spindle rotates, not too tight. Finally still must pass a test run, make the main shaft in the work can not only meet the accuracy requirement, bearing without fever, long-term operation does not exceed 70 ℃. (3) for shaft are installed on the tapered roller bearing clearance, may be adjusted through the bearing cover pad. Adjustment, the bearing cover first not padded, directly on the bearing cover with screw press, with proper clearance in the bearing, axis of rotation handle resistance should be small. Then use A feeler at A clearance, and according to the value of A padded. If the size of the mat is not appropriate, also can match the B mill bearing cover. Three, other types of bearing assembly adjusting characteristics (1) deep groove ball bearing is widely used, when installation should pay attention to choose suitable cooperate relationship. After assembling bearings between the ball and the raceway should no clearance or produce only a small amount of preload. (2) the thrust ball bearings or two-way thrust ball bearings when installation, pay attention to not make axis of bearing supporting surface is skewed. Thrust ball bearings are usually in pairs to decorate, mostly have the preload. Clamping force to big to appeared the maximum axial load, the load bearing of the elastic deformation, does not affect another bearing static ring in the case of not affected by load following rotation. Installation should also pay attention to the static and dynamic circle cannot be installed backwards. Moving coil for transition fit between hole and shaft, static circle between hole and shaft are 0. 20. 3 mm gap. Taper hole spherical roller bearings (3) on the main shaft is installed, make through nut bearing inner ring axial movement along the cone shaft neck do, bearing radial clearance adjustment. Adjusting nut should be used according to satisfy the spindle accuracy requirement, and the principle of bearing temperature rise is not high, you should check the spindle axis neck and taper error or replace new bearing.