Pump bearing design
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There was a domestically produced pump on site; due to its high flow rate and large impeller, and because the medium involved was sulfuric acid, there was no mechanism for balancing axial forces, which resulted in excessive axial force on the pump. The pump’s bearings are 6314 types: one at the impeller end and two at the coupling end; both axial ends are restrained only by the bearing caps. The current situation is that significant noise appears around one week after the start of use of the front bearing, which eventually leads to its damage. It is currently speculated that during operation, the shaft moves forward together with the bearings, and the axial force is supported only by the front bearing, resulting in rapid damage to the bearings. I would like to ask everyone: since there is also an overfit between the outer ring of the bearing and the bearing hole, and knocking is required during installation, can the axial force push the bearing forward within the bearing housing? Anything else? How is the bearing of pumps generally designed to be appropriate?
The bearings for the pump should be 6314 or 7314; one 6314 bearing should be used at the impeller end, while a pair of 7314 thrust bearings should be installed at the coupling end. This will resolve the problem you mentioned. The 6314 bearing is a centrifugal bearing and cannot be used as a thrust bearing at the coupling end; even if you install 10 of them, it won’t solve the issue.
This post was last edited by 276495457 on 2011-5-31 11:53. It involves a pair of thrust bearings and one radial bearing; I’ve done this before with a pair of 6310 bearings – I replaced the two thrust bearings and adjusted the clearance as needed
At the coupling end, there are 7314BDB bearings (1 set, 40° contact angle, mounted on the back side), and lock nuts are used to secure these bearings to the pump shaft in order to withstand axial forces. At the impeller end, there are cylindrical roller bearings NU314, which are used to withstand radial forces.
Reply to 1# strong1125: Create a few balance holes on the impeller to counteract most of the axial force; the remaining axial force can then be handled by angular contact ball bearings.