 FREEDGUY wrote:
Thanks Lonn, those are not quite what I expected a "bearing" to look like LOL!! |
That's exactly why they're referred to as 'water pump' bearings... it's not a typical sealed cartridge, or pillow block, flange, or needle roller bearing.
Water pump bearings are primarily used in a housing where one end is on the fanbelt sheave, the other end is on the impeller. In doing so, there's really only one machining process for making the centrifugal pump work... bore the axis from the volute through the casting nose, and it's done, and the only 'fancy' part, is the cutting head on the boring tool... alignment is perfect in one shot. Combine the unitized pump bearing with a mechanical seal and a cup, you've got an entire rebuild kit in one nice little box.
The fact that it's a unitized assembly (bearing with shaft) has some other advantages... the shaft is actually the running surface for the rollers, so the total assembly is much more compact, and there's no need to worry about clearances and bearing preload, just push the cartridge in and be done.
It is for the reason of compact simplicity, that water-pump bearings get used for all sorts of 'other' tasks. When the world of CNC appeared, manufacturers realized that they could drill a hole in the shaft end, and thread it for a bolt or stud, and use the water pump bearing cartridge as a high capacity precision roller guide, or as a 'cam follower', hence it now is used for all sorts of things... and for that reason, production volume is much higher, which makes commensurate costs LOWER, and that is reflected at by lower price across the sales counter. Handy things, they are...
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