Grinding machine static SKF bearing several experiences of maintenance - bearing knowledge

Static pressure SKF bearing, with its high rotary precision, good rigidity, high bearing capacity, no wear, high durability and is widely used in M210, M131W, 3160 a grinding machine, and 2 a710, FYT10 kong boring head. With the development of numerical control technology, static pressure SKF bearing is widely used in machining center and other CNC machine tool spindle. The first engine plant yituo co. LTD. , has a lot of static pressure grinding machine and the static pressure kong boring head, made some exploration and attempt in the maintenance, several experiences have been obtained. 1. Small 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 beta theoretical value is 1. 2 to 1. Based on years of experience between 5 and 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 value (e The center of the spindle and bearing shell geometric eccentricity) Best, make the beta. ( 3) Fit in the oil chamber not spindle, the oil outlet oil column must be consistent ( Observation) , if not consistent, should be taken to change the choke aperture method, to change its flow. 4 cavity, for example, general, left, right cavity under the oil column of between 20 ~ 25 mm, pore diameter of 0. 25 ~ 0. 4mm。 2. Film feedback choke film throttling SKF 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 approach is: 1. 4 mm thick film instead of 4 mm thick membrane rigidity, the inferior vena pad 0. 5 mm thick foil paper, make the spindle adjusting to higher than the ideal position 0. The location of the 5 mm. Purpose is when the main shaft bearing ( Grinding wheel weight, cutting force) Later, just return to the ideal center. 3. Fuel supply system to improve the static pressure SKF bearing oil supply system, in addition to the coarse and fine filter, the rest of the various components of static pressure SKF bearing plays a protective role. On the basis of the original system to improve the oil supply system. ( 1) After the throttle plate of oil outlet pressure relay and pressure gauge, Originally in front of the accumulator) So that can make the operator to see the size of the cavity pressure and the inlet pressure. When the differential pressure is greater than a certain value, in order to stop immediately, to avoid bearing lock. Such as: inlet pressure 2 mpa, the oral cavity pressure 1. 2 to 1. 6 mpa, less than 1. 2 mpa will stop. ( 2) Increased digital detection device between static pressure of SKF bearing spindle and bearing shell is 0. 04 ~ 0. 5 mm gap, during which the oil has a certain resistance, testing the resistance change, can be learned that period gap size. For spindle, bearings for other, measuring the resistance change. To the signal processing of backwardness to photoelectric amplifier alarm and control system, control of the spindle motor start-stop, to avoid friction shaft with tile.