CNC milling machine spindle bearing assembly have? Rigidity is important

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 planning of internal bearing structure and installation method. For everyone to share, below the main shaft bearing arrangement and configuration and adjusting method. A, angular contact ball bearing in the spindle on the configuration and preloaded, angular contact ball bearings usually arrangement. 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, thus, increase the radial and axial rigidity, resistance to deformation would, however, is the most commonly used one kind of the bearing arrangement. 2, angular contact ball bearing preloaded. In order to make the configuration of angular contact ball bearing spindle progress, strengthen rigidity, precision required to load bearing additive. Advance of loading to slightly greater than or equal to work load. To use more is to use ordinary bearing liner width difference between inner and outer ring, under the action of nut, for bearing preload. On average equipment, just sensitive spindle operation can be ensured and the temperature is low, and can meet the job requirements of rigidity is suitable for assembly. Repair, are usually based on the width of the original liner is poor at appropriate stop adjustment. About high precision rotary spindle, the commonly used method is in the liner between the bearing inner and outer ring, inner bushing can slightly oblique, 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 the resistance can be similar to outer sleeve. Second, tapered roller bearing on the spindle configuration and adjust 1, tapered roller bearing in the spindle on the common arrangement. Tapered roller bearing on the spindle usually has four arrangement: (1) put a bearing spindle before and after the construction. (2) the front-end device in back-to-back way two bearing spindle and put a cylindrical roller bearing the back-end. (3) front-end device in back-to-back way two bearing spindle. A backend device bearing, and a few spring down the outer ring to eliminate clearance. (4) the front-end device two bearing spindle in axial fixation. Backend device two bearings, the outer ring allows the axial moving. 2, tapered roller bearing adjustment in the assembly (1) strict control bearing inner hole and shaft. Must make the bearing inner ring cooperate neither loose in the journal, and the axial moving nimbly. Request the inner and outer ring assembly, in the journal and bearing hole with both hands thumb just can push to cooperate as appropriate. (2) adjusting nut to bearing the proper preload, has the corresponding clearance with spindle maximum speed. Adjustment, to tighten the nut side, the side of the spindle rotation. Have a little resistance make the spindle rotates, not too tight. Finally also required after test run, make the main shaft in the work can meet the precision request, bearing without fever, long-term operation does not exceed 70 ℃. (3) on the device in the axis of the tapered roller bearing clearance, can be adjusted through bearing cover pad to stop. Adjustment, the bearing cover first not padded, directly on the bearing cover with screw press, with appropriate clearance in the bearing, axis of rotation handle resistance should be small. Then use A feeler gauge measurement at A clearance, and on the basis of A value add pad. 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 has been widely applied, unit should pay attention to when choosing appropriate cooperate relationship. After assembling bearings between the ball and the raceway should no clearance or produce only a small amount of preload. (2) thrust ball bearing or bidirectional thrust ball bearing assembly, pay attention to not make the axis is tilted to bearing supporting surface. Thrust ball bearings are usually in pairs to decorate, mostly have the preload. Clamping force to present the maximum axial load, the larger the load bearing of the elastic deformation, does not affect another bearing static ring in load under the condition of not with rotation. Device should also pay attention to the static ring and the moving coil 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 device, through the nut to make bearing inner ring axial moving along the cone shaft neck do, complete bearing radial clearance adjustment. Adjusting nut should satisfy the spindle using precision request, and stop the control, the criterion of bearing temperature rise is not high, you should check the spindle axis neck and taper error or change a new bearing.