Precision bearings according to ISO grading standards are divided into: P0, P6, P5, P4, P2. Rank higher in turn, where P0 is the general accuracy, other grades are precision level. Of course, different classification standards, different types of bearings, their classification method somewhat different, but the meaning is to the. The use of performance requirements of precision bearings rotating body with high runout accuracy, high-speed rotation and small changes in friction and friction.
2013年8月22日星期四
Film feedback restrictor
Feedback throttling film Precision 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 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.
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