Structure and performance characteristics of fag bearing

• The contact angle of thrust angular contact ball bearing is generally 60 °. The commonly used thrust angular contact ball bearing is generally a two-way thrust angular contact ball bearing, which is mainly used for the spindle of precision machine tools. It is generally used together with double row cylindrical roller bearing, and can bear two-way axial load. It has the advantages of high precision, good rigidity, low temperature rise, high speed, convenient assembly and disassembly, etc.

Deep groove ball bearing in fag bearing

• Structurally, each ring of deep groove ball bearing has a continuous groove raceway with a cross-section of about one-third of the circumference of the equatorial circle of the ball. Deep groove ball bearing is mainly used to bear radial load and certain axial load. When the radial clearance of the bearing increases, it has the property of angular contact ball bearing and can bear the alternating axial load in two directions. Compared with other types of bearings with the same size, this kind of bearing has small friction coefficient, high limit speed and high precision. It is the preferred bearing type for user selection. Deep groove ball bearing has simple structure and convenient use. It is a kind of fag bearing with large production volume and wide application range.
• Thrust tapered roller bearing in fag bearing
• Because the rolling element in the thrust tapered roller bearing is a tapered roller, the rolling bus and the raceway bus of the washer meet at a certain point on the axis line of the bearing in structure, so the rolling surface can form pure rolling, and the limit speed is higher than that of the thrust cylindrical roller bearing. Features: thrust tapered roller bearing can bear unidirectional axial load. The type code of thrust tapered roller bearing is 90000.

Structure and performance characteristics of double row tapered roller bearing in fag bearing

• There are many structures of double row tapered roller bearings, a large number of which are 35000 type. There is a double raceway outer ring and two inner rings. There is a spacer between the two inner rings. The clearance can be adjusted by changing the thickness of the spacer. This kind of bearing can bear both radial load and bidirectional axial load, and can limit the axial displacement of shaft and shell within the range of axial clearance of bearing. Structural characteristics of tapered roller bearing. The type code of tapered roller bearing is 30000, and the tapered roller bearing is a separate bearing. Tapered roller bearings are mainly used to bear the combined radial and axial load dominated by radial load. Compared with the ball bearing, the bearing speed and bearing angle are large. Tapered roller bearing can bear axial load in one direction and limit axial displacement of shaft or shell in one direction.
• Hydrostatic NSK bearing has high rotation accuracy, good rigidity, high bearing capacity, no wear and high durability. The following are some experience gained in the exploration and attempt of hydrostatic NSK bearing in the maintenance process, which is for your reference only.

Orifice restrictor:fag bearing

• Change the internal throttling into external throttling, and install a pressure gauge to display the pressure of the upper and lower chambers immediately. It makes the maintenance convenient, especially it can be easily cleaned regularly, which is unmatched by the internal throttle.
• Throttle ratio. Throttle ratio β The theoretical value of is 1.2 ~ 1.5, and 1.25 is better according to many years of experience. In this way, during maintenance, it is necessary to strictly control the geometric accuracy of the main shaft, the geometric accuracy of the front and rear bearing shells, coaxiality, roundness and taper, so as to ensure β Value. Determine the E value according to the bearing capacity of the machine tool (the eccentricity of the geometric center of the main shaft and bearing bush) β Value.
• If the orifice diameter of each oil column is not the same, the orifice diameter of each oil column must be observed. If the orifice diameter of each oil column is not the same, the orifice diameter must be changed. Take 4 cavities as an example. Generally, the oil column of the lower, left and right cavities is between 20 ~ 25mm, and the diameter of the small hole is 0.25 ~ 0.4mm.

Film feedback restrictor:fag bearing

• The stiffness of thin film feedback throttling bearing is very large, but the phenomena such as pad holding, roughening and pressure drop often occur in the operation of machine tools. The key of film feedback is film. In practice, it is considered that the main reasons for bearing bush locking and galling are: 
•  plastic deformation of film; ② Feedback is slow. When the external load changes suddenly and the film has not reacted, the shaft and pad have been rubbed; ③ Film 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 adopted. The specific method is: change the 1.4mm thick film into 4mm thick rigid film, pad 0.05mm thick tin foil paper in the lower cavity, and 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 wheel weight, cutting force).

Improvement of oil supply system:fag bearing

• In the oil supply system of hydrostatic NSK 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.
• The oil outlet behind the throttle plate is connected with a pressure relay and a pressure gauge (originally in front of the accumulator), so that the operator can see the cavity pressure and NSK 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, NSK pressure is 2MPa, outlet cavity pressure is 1.2 ~ 1.6Mpa, and shutdown is required if it is lower than 1.2MPa.
• Add digital detection device:
• There is a gap of 0.04 ~ 0.05mm between the main shaft and bearing bush of hydrostatic NSK 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 phase 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 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.