Archive through July 15, 2014

[elamott]

I was wondering if I could tap some of the great knowledge that is on this sight and clear up something for me. I have included a picture if the rotor bearing assembly of my QA42 snow blower/thrower. The picture shows the rotor sprocket and shaft, a bushing, the collar that holds the bearing on bushing and the bearing.
My question is. The bearing collar is held on the bushing by a set screw but there is nothing that holds the bushing to the shaft. When I took the rotor off of the housing, the bearing, collar and bushing was loose and could be moved easily. I am not sure if this is good, bad or makes no difference.
Any comments appreciated.
Earl LaMott

 

[jpatchett]

Earl,
I think you are describing the bearings at each the end of the auger that are fixed to the housing. These are eccentric bearings that have locking collars. The principle behind their function is hard to explain. The set screw locks the collar to keep it from rotating and the collar locks the inner race of the bearing on the shaft.

https://www.youtube.com/watch?v=LPFn_AVz-e0

I would skip the first minute and I don't torque the set screws
The video is of a shaft and two pillow block bearings, but it is the same principle. The gray painted cast blocks in the video serve the same purpose as each end of the thrower housing. The video states the locking collars need to rotate in the same direction as the normal rotation of the shaft (auger). I am not sure I agree with this.

Jim

 

[rrschmitt]

Earl,

I don't believe there should be a bushing between the shaft and bearing. Either your rotor/auger shaft has been turned down in the past and the bushing added to compensate or the PO couldn't get the correct size bearing and added the bushing to fill the gap. With the correct size bearing, the locking collar will lock the bearing to the shaft. If your shaft was previously turned down the only way to keep the bushing from moving would be weld the bushing to the shaft at the end with several short welds.

 

[joligschlaeger]

Thanks Kraig McConaughey. I knew I had seen a chart some time ago but couldn't seem to find it last night, just kept falling asleep.

 

[elamott]

Ron:
Your idea that there should not be a bushing makes sense to me. I will have to check on the shaft size of a new bearing and then decide what to do. The tack welding the bushing sounds like a good idea if I need it. I don't like the whole assembly moving like it was.
Thanks for the idea.
Earl

 

[hydroharry]

Earl L - something doesn't seem quite right in your picture. What Jim P was saying about the locations of the bearings is correct - the bearings should be located on the outside ends of the auger shaft - which is outside the chain sprocket. If I'm viewing your picture correctly your showing the bearing on the inside of the chain sprocket. The bearing used on the QA snow throwers is the same bearing used on the PTO clutch - which fits a 1" diameter shaft (same as the engine crankshaft). I can't figure out what your bearing is on in the picture - it looks like a long shaft which I don't understand. I've overhauled and installed bearings in several of these units and I don't recall ever seeing a bushing - and if the locking collar is locked to the bushing then the sprocket shaft is just going to turn inside the bushing and the bearing wouldn't do anything. Something is just not right here. Also, my Parts book doesn't show or mention anything about a bushing - it does call out a sprocket assembly tho.

Here's a pic of the sprocket assembly (stolen from Charlies's site). This sure looks to me like it has a 1" shaft - so I have to think someone changed your sprocket and used so small a shaft. Even if you weld that bushing to the shaft I wonder how long it will hold up.

 

[hydroharry]

Here's the pic of the sprocket assembly I mentioned in the post below.

 

[hydroharry]

I must'a broke this thing again last nite.

Charlie - saw your note in "purple print" just below those colorful boxes above and sent something yesterday.

 

[hydroharry]

I guess this thing is really broke. Maybe those storms in the Midwest are reaking havoc on it. It's been 18 hours since anyone, other than me, posted a message.

 

[kmcconaughey]

Hydro, I'm here, lurking.