Bearing bore and outside diameter of shaft, bearing installation and when is important when combined with loose shell the mating surfaces will have a relative slide known as creep. Creeping wear combined with surface damage once the shaft or casing wear powder could penetrate and SKF bearings, vibration caused by internal heating and damage. When interference is too large can cause circles within the outer ring outside diameter smaller or larger diameter reduces the bearing internal clearance. -Select application designed to consider the nature, size, temperature of the bearing load conditions, the outer ring of the inner ring rotation-like conditions
Bearing quality is better, but always be bad, here are four kinds of bearings for use in the common cause of damage to some of the recommendations, if we strictly in accordance with the following requirements, bearings can be used for a long time.
First, the weary (about 34%) fatigue damage is a common way to damage the bearing. Common causes of fatigue damage might be: long-term overload operation of bearings; not timely maintenance; improper maintenance; ageing of the equipment. Suggest that you select the appropriate type of bearing, scheduled to replace the tired bearings.
Second, the poor lubrication (about 36%) according to the survey, poor lubrication is one of the major causes of premature bearing damage. Major causes include: no lubrication or lubricant in a timely manner; lubricants or lubricant is not filling the place; selection of lubricants or lubricant improper; lubrication method is inaccurate, and so on. Recommends that you select the exact lubricant or lubricant, using the exact notation lubrication.
Third, the improper installation (about 16%) installation using brute force, directly with a hammer hitting bearings FAG bearings damage the largest are a major cause of deformation. Installation is not in place, install a biased or that do not have bearing, causing the bearing clearance is too small. Inner and outer rings are not in uniform rotation of the Central, resulting in different hearts. Suggest that you select the proper bearing installation tool or professional, installed using special instruments detect.
Four, pollution (about 14%) pollution will result in premature bearing damage, pollution is dust, scrap metal into the bearing. Major causes include: prematurely opened bearing package before use, pollution; installation work environment is clean, pollution; bearing's working environment is clean, medium pollution. Suggested packaging before use it is best not to open bearings; maintaining a clean installation environment during installation, to be used to wash the bearings; enhanced bearing sealing device.
For clearance not adjustment of bearing, due to its radial clearance in manufacturing Shi on has by standard determines good has, cannot for adjustment, this class bearing mounted in axis trail Shang or bearing block hole within zhihou, actual of radial clearance called Assembly radial clearance, Assembly Shi to makes Assembly radial clearance of size just can in running in the caused necessary of work radial clearance, to guarantee bearing flexible turn. When this type of NSK bearings, due to elongation of shaft in the heat when the temperature of the seat relative displacement occurs, so that the radial clearance of bearings to reduce, or even rolling stuck in between inside and outside the ring. If double bearing in rolling bearing of a bearing (in another fixed to the shaft and the bearing housings) and allow axial clearance between the side cover to avoid these phenomena.
Symptoms:
1) when engine running stable under normal circumstances there is no sound, dull when an abrupt change in engine speed to "boring boring" knocking, accompanied by vibration phenomena.
2) engine load changes, the sound clear. Speed, the higher the sound bigger.
3) single cylinder "cutoff" feel any change when, while in the adjacent cylinder sound cutoff at the same time will be significantly reduced.
Reason:
1) crank shaft and axle clearance is too large.
2) the crankshaft with the axial clearance is too large.
3) crankshaft bearing cap bolts are loose.
4) crankshaft bearings and axle ablated particles poor lubrication bearing alloy rings.
5) bending deformation of crankshafts, crankshaft Out-of-round.
6) crankshaft bearing and the bearing seat relative rotation.
Diagnosis:
1) sound from the lower portion of the cylinder close to the crank case. Significant drop in oil pressure. Jitter under the engine in low and medium speed throttle, sounds an obvious and dull drum accompanied by engine vibration.
2) high-speed running engine, larger airframe vibration and oil pressure dropped significantly, then the gap too large or for bearing and axle journal bearing alloy ablation shedding.
3) single cylinder experimental noise cutoff changed little, and two adjacent cylinders cut noise decreased significantly or disappear when the fire, or between the two cylinders crankshaft bearings.
4) high speed large airframe vibration, oscillating shaking phenomenon, also issued heavy and large "bang bang" knocking the crankshaft.
5) sound but increased with temperature, high speed noise becomes cluttered, may be the crankshaft.



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