Flange bearing question??

[tinkerer]

I am building a generator using a surplus center Yanmar engine. I have a short stub shaft that will be attached to the flywheel that I plan on putting a love-joy type coupler on and then driving a shaft either supported by pillow bearings or one large flange type bearing that will be attached to the engine itself. I'm not sure how to explain myself, but I'll try to make it clear. I plan on having some standoffs coming off the rear of the engine that will mount to a flat plate that the flange bearing will be attached too that holds the shaft that is driven by the stub shaft on the engine. Now my question is: Is there a flange bearing that can hold a shaft by itself and handle a sideload from a belt? If so, what is it called? I would rather go this route to save a little room. I would also think that one bearing would be more efficient than two.
Ben

[Frank S]

It sounds to me like you are attempting to make an overhung load adapter but plan on isolating any minor eccentricity of the shafts. and mounting an outboard pulley. If so NO! you are thinking of an "E" piloted flange bearing but 1 bearing of any type or design will never do the job as well as 2 and any flanged bearing that  I know of unless the housing contains 2 bearings, is going to allow the shaft to wobble about its axis limited only by the fit of the love joy coupling.
you should either machine a bell housing to fit the engine then machine a piloted bearing housing to accept 2 bearing with some spacing between them  making sure to dial indicate "0" center and dowel the bell housing to the engine if possible or if you want only 1 bearing you still need to do the above but lose the coupling and make fit over shaft extension. You will still be transmitting some lateral forces through the main bearings of the engine but your bell housing will take the brunt of the side loading.   

[Frank S]

here is an example of a bearing housing I made for a different application but the principal will be similar

[tinkerer]

Thanks for the reply! So, with your input, I've got another idea. My stub shaft that bolts to my flywheel is about 8 inches long. I was planning on cutting it off shorter and attaching the love-joy type coupler on it. But, how about leaving it long and building a bell housing of some sort that supports the stub shaft with a flange bearing and then attaching my pulley to the end of the shaft. I think you described something similiar to this in your post. I hope I have described it in a way that can be understood. A little force would be asserted on the engine bearings but not as much.
Ben

[tinkerer]

Here is a link to something like I was originally planning on doing. I knew they made such a thing but didn't know what they were called.

http://www.hayescouplings.com/index.php/products/original_bearing_supports

Of course, its a little out of my budget...

[Frank S]

That Hayes unit is exactly what you need If you note it has 2 bearings in the housing but hte stub shaft is connected to the flywheel VIA a flex plate with a spline this totally isolates any main bearing loading.
you didn't mention which model your Yanmar is if it is a 3 or 4 cylinder model then I will have a SAE #5 flywheel housing. I really don't care for a rigid mount IE single bearing plated to a bell housing with the stub sticking outboard even though I did mention the possibility. as the engine ages there will be wear in the main bearings and the side loading can cause crankshaft to fail. but if it is well engineered and perfectly doweled to center then you could expect a reasonably good life cycle.
mounting a bearing outboard of  a pulley if troublesome at best when the time comes for belt replacement.
Floating the pulley on its own bearings  with an outboard flex plate connecting it to the shaft
I just now drew this one up I did not bother with the unknowns like shaft size this is for reference only 

[Frank S]

If you require a scaled drawing just email me some pictures of your engine with exact measurements best if right on the pictures and I can design what ever you require
I do recommend you forget about a flanged or pillow block bearing though spending a little up front for machining if you do not own a lathe will pay for itself in the long run 

[tinkerer]

Frank, thanks for your input. My engine is a Yanmar 2TNV70. I'll try to get you some pictures and measurements and see what you think. By they way, your "pictures" that you drew up are fantastic! I assume your using some kind of CAD program? I'm guessing you have some experience in machining and engineering. Thanks again for your help!
Ben

[mobile_bob]

another option for your drive

remove the stub shaft assembly

make up an adapter plate to mate to the flywheel and attach one half of the love joy to it
(press fit, and weld) leaving the lovejoy half center bore open...

into that centerbore fit a bronze bushing

now make up a shaft , machine a step on the end to fit into this bushing
and slide the other half of the lovejoy and its spider into position,

what you have now is a lovejoy with your extension shaft going through the outer lovejoy half, through
the center of the spider, and into the bushing of the inner lovejoy.

now you can use a standard flange mount single brg unit to support the other end.

the inner bushing/shaft interface do not turn against each other, they rotate together so there is no wear
the bushing just supports and centers the inside of the shaft nearest the engine, and the outer flange supports the outer end of the shaft.

the fit between the bushing and the step on the shaft should be a slip fit, no need to be any tighter than that of a pilot bushing used in the end of a crankshaft with a standard transmission as used in a car.

you are going to buy a lovejoy/spider anyway, so the only added expense is for the bushing and some machine work for the step on the shaft

even the machining can be avoided if you pick one half of the love joy to be a larger shaft size, allowing a bushing to be used to fit a stock piece of cold rolled steel.

bob g

[Frank S]

Ben does your engine actually have a flywheel housing or just the starter mount plate
I am seeing that most of the engines like yours just have the flywheel with the stub shaft mounted And from what I have been reading the engines really do not like any side loading of the shaft which would be true of almost all engines except those have a crank shaft specifically made with for pulleys. even those would benefit from a PTO adapter.
Hayes makes a complete line of engine adapters
I read on this forum where you could possibly get away with a serpentine pulley mounted directly to the stub shaft. But my experience tell me to tell you not to unless you mount a bearing outboard of the pulley similar to what you originally asked
Keep in mind that rigidity and centering is of top importance. this would however be cheaper than machining an adapter like  I posted a mock up of That picture is in no way to be considered a final design as the shaft  to pulley coupling needs to have away  to isolate any vibration. IE a rubber torque spider or bushings to absorb shock loads.
Is your stub-shaft welded to the mounting plate or that of a 1 piece machined construction. The ones I saw while searching were all welded and looked very dodgy to me.
you asked about my cad program I am still using solidworks 2011 because I want to build 2 new computers with I core7, twin 1 terabyte HDD 128 GB ram and duel 2 GB multi monitor graphs cards these will cost me about 5 grand in parts to assemble Plus another several grand in software before I am finished the ones I have now can only handle 8 Gb of DDR2 ram but I am running 2  32" monitors on both of them I want to go to 3 32" & 1 72 " on my new computers.
And OH yes I have been designing and machine / fabricating things since 1965 100% self educated but in many ways dumb as a box of hammers with broken handles.  
   

[Tom Reed]

Another simple way to do it would be to mount an automotive u-joint from a drive shaft to the crank and mount the flange/pillow bearing on the outboard side. That would tolerate a lot of slop.

[Frank S]

Another simple way to do it would be to mount an automotive u-joint from a drive shaft to the crank and mount the flange/pillow bearing on the outboard side. That would tolerate a lot of slop.

TOm your way would be similar to using a flex plate or a bushed spline setup yes that would be superior to a rigidly mounted stub shaft the stub shaft is not meant to take loads other than inline connections just like hooking an electric motor up to a pump
without a factory technical data sheet spelling out available overhung loads it is a best guess scenario

[SteveU.]

Hmm More and more systems being KISS built up, assembled and put in service using the 180 degree opposing Alt's/gen-heads being "V" belt driven off of a crankshaft/flywheel mounted stub shaft.
FrankS is correct. Use a large pulley (better for belt life) and shaft tapered bushing mount it so the pulley edge rests against the flywheel for support.

Bet the cost savings in precision machining and bought parts will buy the extra pulley and belt pairs.
This way with gen-head failure you will always have at least half power.
Easy to set up spares for a triple redundancy also.

Regards
Steve Unruh

[Frank S]

Hmm More and more systems being KISS built up, assembled and put in service using the 180 degree opposing Alt's/gen-heads being "V" belt driven off of a crankshaft/flywheel mounted stub shaft.
FrankS is correct. Use a large pulley (better for belt life) and shaft tapered bushing mount it so the pulley edge rests against the flywheel for support.

Bet the cost savings in precision machining and bought parts will buy the extra pulley and belt pairs.
This way with gen-head failure you will always have at least half power.
Easy to set up spares for a triple redundancy also.

Regards
Steve Unruh

Steve most engines are not designed for full HP overhung loads excepting for engines like Lister Changa or other clones
Small engines like Briggs, Honda, Kohlor, Robbin. and the likes I consider as throwaway engines are used every day with pulleys mounted on them And yes even engines like the Yanmar & Kubota are used with pulleys direct mounted ,
But when was the last time anyone can remember a full HP side loading drive directly mounted to the flywheel of a Cummins or Detroit, or caterpillar, Volvo , Deutch, John Deer, Ford, or any other large engine?
A data sheet signed off by a factory engineer stating % of longevity of full HP side loading versus inline coupling is the only way I would sign off on mounting a pulley on the stub-shaft of my own equipment let alone give someone advice who I do not even know. I like to design things that will outlast the prime mover. I have truck ramps for RGN trailers that are now mounted on their fourth generation semi tractors

[SteveU.]

Hi FrankS.
Maybe you did not realize the purpose of dual opposing load take off was to balance out side thrusts??

This engine is ~15-20 horsepower, yes?
In answer to your posed question about Cummins, Detriots, Caterpillars, Deutch, John Deere and Ford large engine pulley belted side thrust load take offs . . . open hoods and look at the other end. Almost every over the road application IS taking off pulley side thrusted loads in the order of 15-20 horsepower in the cumulative alternator, power steering, air conditioning and air compressor and even a vacuum pump loads. All, mostly pulling upwards. With some attempt to balance side to side.

This dual opposing concept is being used on a Kubota DG972 three cylinder and was ran by and approved by the factory Kubota Applications Engineer. Single side load take off for full power was not.

FrankS there is as much to learn by just going out in the world and look and seeing what IS, Has and HAS NOT worked on common engineering power drive applications. KISS, as long as it proves out with the hours and varied usage, rules in the end.

Regards
Steve Unruh