in the maintenance carried out some exploration and attempts to obtain experience points.

Several grinder hydrostatic bearing repair experience
Author: Time :2008 -10-20 10:15:10

Rotary hydrostatic bearing its high accuracy, good rigidity, high capacity, no wear, high durability and is widely used M210, M131W, 3160A grinder and 2A710, FYT10 Diamond boring head. With the development of digital technology, hydrostatic bearings are also widely used in machining centers, CNC machine tool spindles. YTO AG first engine plant, there are many static pressure and static pressure diamond grinder boring head, in the maintenance carried out some exploration and attempts to obtain experience points.
1 hole restrictor
(A) outside the internal throttle to throttle, and to install the upper and lower chamber pressure gauge real-time display. So easy maintenance, in particular, can easily be cleaned regularly, this is an internal restrictor unmatched.
(2) throttling ratio. Throttling than the theoretical value of β is 1.2 to 1.5, and 1.25 based on years of experience with preferred. So that the maintenance, the need for geometric precision spindle, bearing around the geometric accuracy, concentricity, roundness and taper strictly controlled in order to ensure β values. According to the carrying capacity of the machine to determine the value of e (the geometric center of the spindle and bearing eccentricity), the β value best.
(3) is not installed in the oil chamber spindle, each column of oil out of the oil port must be consistent (observation), if not, should be taken to change the restrictor aperture methods to alter the flow. With 4 cavities, for example, generally lower, left and right chamber of the oil column at between 20 ~ 25mm, hole diameter of 0.25 ~ 0.4mm.
(2) Film feedback restrictor
Feedback throttling film bearing stiffness is great, but the machine in operation often appear hold tile, brushed, lost pressure and so on. The most critical is the feedback film film practice that locking bush, brushed the main reasons are: ① thin plastic deformation due; ② feedback slow. External load mutation, the film did not react when the axis and tile has been rubbed; ③ film fatigue. Film using a long time, fatigue deformation, the equivalent of changing the feedback parameters.

Increasing film thickness and use some of the fatigue resistance of the material, can receive good results. Generally rigid film, a pre-load, reserve gap approach. Specific approach is: the 1.4mm thick rigid 4mm thick film to film, the inferior vena pad 0.05mm thick aluminum foil, so that the spindle than the ideal position to adjust to the high position of 0.05mm. Purpose is force when the spindle (wheel weights, cutting force) after return exactly to the ideal center.

3 Fuel System Improvements

Hydrostatic Bearing test machine  oil supply system, in addition to the coarse filter, fine filter, the rest of the components have a protective effect on the hydrostatic bearing. On the basis of the original system, fuel system improvements.

(A) in the throttle plate after the oil pressure switch and pressure gauge connection port (the original in the accumulator in front), so that the operator can see the chamber pressure and the size of the inlet pressure. When the pressure is greater than a certain value, in order to immediately shut down, in order to avoid bearing locking. Such as: inlet pressure 2MPa, exit chamber pressure 1.2 ~ 1.6MPa, 1.2MPa below will shut down.

(2) increase the number detection device

Hydrostatic bearing between the shaft and the bearing gap of 0.04 ~ 0.05mm, during which the oil has a certain resistance value of the resistance variation detection, it can learn the size of the gap. With spindle pole, bush for another pole, measure the resistance change. After processing this signal sent to the photoelectric alarms and control system amplifier, controls the spindle motor start and stop, in order to avoid friction axis and tile.