Common Damage Forms of Shaft Parts - Diesel Generator
by Starlight Generator dieselgeneratortechMany diesel generator
shaft parts, such as crankshaft, camshaft, drive shaft and so on. The common
damage forms of shaft parts are bending, wear and fracture.
1. Bending Test
The axis of the
shaft-like part must be in line with its axis of rotation, otherwise the shaft
is bent and deformed. As shown in FIGS. 2-9, the axis before the shaft 1 is not
bent is AA, and the axis after bending is BB. When the bending degree of the shaft
is checked, the contact of the differential table 2 is generally used against
the central part of the shaft 1 (if the crankshaft or the camshaft journal is
singular, the intermediate journal can be measured; if the journal is double,
the middle two journals should be measured and the maximum value is taken), and
when the rotating shaft is rotated, The difference between the maximum reading
indicated by the long pointer of the differential table and the minimum
reading, that is, the amount of run out of the shaft on the radial circle.
For some simple shafts,
they can be rolled directly on the flat plate. When rolling, the light leakage
between the shaft and the plate can be observed, according to which the bending
of this kind of parts can be judged.
2.
Examination of Wear
The shape of
shaft-shaped parts is more complicated, some are curved crank (such as
crankshaft), some are tubular (such as half shaft sleeve), some are rod shape
(such as steering pin), and the parts of wear and tear are axle neck.
Figure 2-10 measures
wear of crankshaft connecting rod journal. One half of the maximum value of the
difference measured on the same cross-section is roundness, and one half of the
maximum value of the difference measured on the same longitudinal section is
the cylindrical degree.
The length of the
journal and radius of the circle should also be checked when one or both ends
of the journal have shoulder face bearing thrust.
In order to improve the
inspection efficiency, the wear quantity of axle neck can be measured by
various special limit gauges in the repair unit with single model and large
production scale.
3. Fracture Test
It can be checked by
inspection method and detection method.
Causes of failure of bearing bush of diesel generator
With the expansion of
diesel generator application scope, more and more customers begin to use diesel
generator, followed by more and more problems arising from improper operation.
Here is a brief introduction of diesel generator bearing failure reasons:
1. The lubricating oil
in the oil pan is insufficient or the oil line is not smooth, the engine oil
pump can not supply oil normally or the lubricating oil pressure is too low,
which leads to poor lubrication.
2. The grade of
lubricating oil does not meet the requirements, the lubricating oil is spoiled,
too dirty; the waterproof rubber seal ring of the cylinder liner fails,
resulting in the leakage of cooling water to the oil pan.
3. The clearance between
the journal and the bearing is not up to standard. The gap affects the
formation of lubricating oil film; if the gap is too small, the lubricating oil
is not easy to enter the friction surface of the journal and the bearing, and
can not form the lubricating oil film; if the gap is too large, the vibration
and impact between the journal and the bearing are increased, resulting in the
film rupture of the lubricating oil.
4. When the diesel
generator has just started, especially in winter, when the lubricating oil has
not been fully lubricated, it should work at a very high speed and full load,
or start frequently, run at idle speed for a long time, etc.
5. The diesel engine is
overloaded for a long time and overrotating speed: the temperature of the body
is high, the viscosity of lubricating oil is decreased, the normal lubricating
oil film is not easy to form, the alternating load and the working cycle exceed
the material limit of the bearing liner; Load fluctuation or increase in
fluctuation, resulting in oil bubble rupture.
6. Improper maintenance
and assembly, flange on the journal surface, and uncleaned assembly.
While troubleshooting
the parts themselves, special attention should be paid to finding out and
analyzing the causes of the failure, such as whether the failure of the bearing
bush is due to low lubricating oil pressure, lack of lubricating oil, or dirty
blockage of the oil channel and poor flow of oil, etc. Only when the ultimate
cause of the fault is found and eliminated, can the diesel generator set work
reliably, so as to avoid the similar faults occurring again after the
replacement of the bearing bush.
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Created on Feb 26th 2019 21:29. Viewed 293 times.