NSK bearing static pressure with its high rotary precision, good rigidity, high bearing capacity, no wear and high durability. NSK bearings here is static pressure in the repair process to explore and try to get some experience, is only for your reference.
1 hole choke:
(1). Change the internal throttling to external throttling, and equipped with pressure gauge pressure inferior vena instantly. Make maintenance convenient, especially can easily be regular cleaning, this is an internal choke.
(2). The throttling ratio. Throttle than the theoretical value is between 1.2 ~ 1.5 beta, and according to many years of experience in 1.25 is preferred. In maintenance, so need to before and after the geometrical precision of the spindle, the geometry precision of bearing bush, alignment, roundness and taper of strict control, in order to ensure the beta. Determined according to bearing capacity of the machine tool for e (eccentricity) to the center of the main shaft and bearing shell geometry, the beta value is the best.
(3). The oil cavity when don't put the spindle, the oil outlet of oil column must agree (observation), if inconsistent, should be taken to change the choke aperture method, to change its flow. 4 cavity, for example, generally, left, right cavity under the oil column, between 20 to 25 mm hole diameter is 0.25 ~ 0.4 mm SKF Bearing Static Load Rating http://www.skf-bearings-lb.com/.
2. The film feedback choke:
Film feedback throttle bearing stiffness is very big, but our machine also often appear in running watts, the phenomenon such as hair, off pressure. Thin-film feedback is the most critical, practice that bearing lock, hair, the main reason is: (1) thin film caused by plastic deformation; (2) feedback slowly. External load mutation, film also have no reaction, shaft and tile has been friction; (3) thin film fatigue. Film with long time, fatigue deformation, equivalent to change the feedback parameters.
Increasing the thickness of the film and use some fatigue resistant material, all can get good result. Usually adopt rigid film, preload lotus, reserved aperture method. Specific practice is: will be 1.4 mm thick film instead of 4 mm thick membrane rigidity, in inferior vena pad is 0.05 mm thick foil paper, make the main shaft to adjust to than the ideal place to the location of the 0.05 mm high. Purpose is when the main shaft bearing (after grinding wheel weight, cutting force), just returned to the ideal center.
In fact, under ideal conditions, the so-called permanent INA bearing life is possible.