The static pressure imported bearing has high rotation precision, good steel property, high bearing capacity, no wear and high durability. The following are some of the experiences of static pressure imported bearings in the process of repair and try to obtain, for your reference only. 1. Small orifice restrictor: (1). Change the internal throttling to external throttling, and add a pressure gauge to instantly display the upper and lower chamber pressure. It is easy to maintain, especially it can be cleaned regularly, which is unmatched by the internal throttle. (2). Throttling ratio. The theoretical value of the throttle ratio β is between 1.2 and 1.5, and 1.25 is preferred based on years of experience. In this way, in the maintenance, the geometric accuracy of the main shaft, the geometrical accuracy of the front and rear bearing pads, the coaxiality, the roundness and the taper need to be strictly controlled to ensure the β value. The e value (the eccentricity of the main axis and the geometric center of the bearing bush) is determined according to the load carrying capacity of the machine tool to optimize the β value. (3). When the oil chamber is not equipped with the main shaft, the oil column of each oil outlet must be the same (observation method). If it is inconsistent, the flow rate should be changed by changing the orifice diameter of the throttle. Taking 4 chambers as an example, the oil column of the lower, left and right chambers is generally between 20 and 25 mm, and the diameter of the small holes is 0.25 to 0.4 mm. 2. Thin film feedback throttle: The stiffness of the film feedback throttling bearing is very large, but the phenomenon of holding the tile, pulling the hair, and dropping the pressure often occurs during the operation of the machine tool. The most critical of the film feedback is the film. In practice, the main reasons for the bearing lock and pulling are: 1 plastic deformation of the film; 2 slow feedback. When the external load is abrupt, the shaft and the tile have already rubbed when the film has not reacted; 3 the film is fatigued. The film is used for a long time and fatigue deformation, which is equivalent to changing the feedback parameters. Increasing the thickness of the film and switching to some fatigue-resistant materials can give good results. Generally, a rigid film, a preload, and a gap are reserved. The specific method is: change the 1.4mm thick film to a 4mm thick rigid film, and place a 0.05mm thick tin foil in the lower cavity to adjust the spindle to a position 0.05mm higher than the ideal position. The purpose is to return to the ideal center just after the spindle is stressed (grinding weight, cutting force). 3. Improvement of the oil supply system: In the static pressure inlet bearing oil supply system, except for the coarse filter and the fine filter, the other components have a protective effect on the hydrostatic bearing. The fuel supply system is improved on the basis of the original system. (1). Connect the pressure relay and pressure gauge (originally in front of the accumulator) at the oil outlet behind the throttle plate so that the operator can see the pressure of the chamber and the inlet pressure. When the pressure difference is greater than a certain value, in order to stop immediately, so as to avoid the axle lock. Such as: the inlet pressure 2MPa, the oral pressure 1.2 ~ 1.6MPa, less than 1.2MPa will stop. (2). Add digital detection device: There is a gap of 0.04~0.05mm between the main shaft of the static pressure imported bearing and the bearing bush. The oil in the process has a certain resistance value. When the change of the resistance value is detected, the gap of the period can be known. Take the main shaft as one pole and the bearing bush as the other pole, and measure its resistance change. This signal is processed and sent to the photoelectric alarm and control system amplifier to control the start and stop of the spindle motor to avoid the friction between the shaft and the tile. Indoor Growing Lights,Pendant Lighting,Motion Lights Indoor,Solar Lamps Indoor Foshan Nanhai Pinming Electrical Appliance Co.,Ltd , https://www.mavcadonf.com
Maintenance method for static bearing of imported grinding machine in imported bearing