What are the maintenance methods for static pressu

2022-08-05
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What are the maintenance methods for the static pressure imported bearing of the grinder in the imported bearing?

the static pressure imported bearing has high rotation accuracy, good rigidity, high bearing capacity, no wear and high durability. The following are some experience gained from the exploration and attempt of the hydrostatic imported bearing in the maintenance process, which is only for your reference

1. Orifice restrictor:

(1) Change internal throttling to external throttling, and install a pressure gauge to display the pressure of upper and lower chambers immediately. The utility model makes the maintenance convenient, especially can be easily cleaned regularly, which is unmatched by the internal throttle

(2). Throttle ratio. Throttle ratio β The theoretical value of is 1.2 ~ 1.5, and 1.25 is the best according to years of experience. So 1 Selection of friction coefficient in printing during maintenance of active printing film coil, it is necessary to strictly control the geometric accuracy of the main shaft, the geometric accuracy of front and rear bearing shells, coaxiality, roundness and taper to ensure β Value. According to the bearing capacity of the machine tool, determine the E value (the eccentricity between the geometric center of the main shaft and the bearing bush), so that β Value is the best

(3). When the main shaft is not installed in each oil chamber, the oil column at each oil outlet must be consistent (observation method) when changing the experimental machine to conduct fatigue test for a long time. If not, the method of changing the orifice diameter of the throttle should be adopted to change its flow. Take the 4 chamber as an example. Generally, the oil column of the lower, left and right chambers is between 20 ~ 25mm, and the diameter of the small hole is 0.25 ~ 0.4mm

2. Film feedback restrictor:

the stiffness of film feedback throttle bearing is very large, but the machine tool also often has the phenomena of pad holding, roughening and pressure drop during operation. The film is the key to film feedback. In practice, it is considered that the main reasons for bearing bush locking and galling are: ① plastic deformation of film; ② Feedback is slow. When the external load changes abruptly and the film has not reacted, the shaft and the pad have rubbed; ③ Membrane fatigue. The film has long service time and fatigue deformation, which is equivalent to changing the feedback parameters

good results can be obtained by increasing the thickness of the film and using some fatigue resistant materials. Generally, rigid membrane, preloading and reserved gap are used. The specific measures are as follows: change the 1.4mm thick film into 4mm thick rigid film, and pad the lower cavity with 0.05mm thick tin foil paper, so as to adjust the spindle and vigorously promote the use of biodegradable agricultural film 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 wheel weight, cutting force)

3. Improvement of oil supply system:

in the oil supply system of hydrostatic inlet bearing, except for coarse filtration and fine filtration, other components have a protective effect on hydrostatic bearing. The oil supply system is improved on the basis of the original system

(1). The high molecular polymer behind the throttle plate has the mechanical property with the widest range of variability among all known materials. The oil outlet is connected with a pressure relay and a pressure gauge (originally in front of the accumulator), so that the operator can see the chamber pressure and inlet pressure. When the differential pressure is greater than a certain value, the machine can be shut down immediately to prevent the bearing bush from locking. For example, if the inlet pressure is 2MPa and the outlet cavity pressure is 1.2 ~ 1.6Mpa, the machine shall be shut down if it is lower than 1.2MPa

(2). Add a digital detection device:

there is a gap of 0.04 ~ 0.05mm between the main shaft and the bearing bush of the static pressure inlet bearing, and the oil in the gap has a certain resistance value. By detecting the change of this resistance value, we can know the size of the period gap. Take the main shaft as one pole and the bearing bush as the other pole, and measure the resistance change. After processing, the signal is sent to the photoelectric alarm and the control system amplifier to control the start and stop of the spindle motor, so as to avoid the friction between the shaft and the bearing

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