Failure of the Karit Ehara high-speed pump
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This post was last edited by Worker @ on 2017-5-26 07:17. The most recent maintenance involved adjusting and reducing the intermediate speed shaft, as well as the axial adjustment shims for the high speed shaft. The reinstallation of the turning gear is too tight, causing significant vibration when it is in operation, with a value of 11 mm/s. It was in use for a few days when suddenly there was no flow; the pump did not vibrate, so I suspect the shaft is broken. Upon disassembly, it was found that the gear had been worn flat and the rolling bearing of the medium-speed shaft was damaged. This is a rather serious fault, and the cause has not been identified yet. There is time to upload pictures.
Let everyone participate in the analysis to learn together and improve.
First, the bearing failed, but it wasn’t detected in time; subsequently, the center distance between the gear shafts was disrupted as a result of this failed bearing
During the adjustment process, the meshing clearance between the two gears was not taken into account, which led to tight turning of the disk; this shows that the maintenance personnel were careless
Agree with the view from floor 5; the order of damage should be bearings first, followed by gears. I believe the cause of the damage is related to the owner’s most recent maintenance work. The owner mentioned that during that maintenance, the axial shims between the medium-speed shaft and the high-speed shaft were reduced, which resulted in the shafts being tightened too much. This shows that the medium-speed shaft and the high-speed shaft are fitted too tightly; the gears not only have to bear the weight of their own shafts but also additional shear stresses resulting from the tight fit between the two shafts, which ultimately leads to gear overload and failure. After the gear failed due to overload, the speed of the medium-speed shaft decreased, resulting in the grinding flat of the gear. It would be best for the poster to also provide an orthogonal cross-sectional view of the pump, as this will help with a more accurate analysis. The above are purely personal opinions; please don’t criticize if you disagree!
If the turning gear is tight and there is significant vibration, the machine must be stopped to find out the cause. Driving forcefully brings consequences. Now, the majority of the equipment is scrapped. . .
The medium-speed shaft and high-speed shaft axial adjustment shims – do they reduce the distance between the centers of the two shafts?
It’s better to return it to the factory, or buy original parts to replace it
Everyone believes that it was an overly small axial clearance that caused the bearing damage