Conveyor design...

[Sandhill Crane]

After installing the new hydraulic motor and top drum it became obvious my three pillow block plan to align the new motor wasn't working out well. Two pillow blocks on one side worked on the work bench to align the motor. The two opposite sides of the drum however, are adjustable for belt tracking with a tube-in-tube arrangement. That doesn't work with three pillow blocks on the same shaft unless the double pair with the integral motor mount are mounted on some type of swivel. That could be done but adding the swivel would change the height of the drum unless the existing tube-in-tube mount for belt tracking is modified. Adding the swivel on the reese tube might work but there is not much room, and the adjustment push plate would need relocating somehow.
At this point I may put it back together as it was originally, with a solid coupling and cantilevered hydraulic motor, and see if the motor shaft shears again. Or rather, when...it shears again.
I guess I don't understand how it worked as long as it did, because any belt tracking adjustment would seem to mis-align the motor and drum shafts.
Going to head out and give it one more go with aligning the three pillow blocks before pulling the drum completely out again.
Any comments, or suggestions to try a new approach are very welcome...
Same for any photos of your conveyor hydraulic motor mount if you have one.

 

[dave_dj1]

Run the conveyor off a pulley? That would at least allow for some flexability.

 

[cantoo]

A bit of work but maybe change to a flange style bearing mounted on a thick plate welded to the tube or even cut off part of the tube? Hydraulic motor would then hang off end of shaft? A really crude drawing.

 

[Sandhill Crane]

dave-dj1: I have considered a chain drive. Although I think there is something about side loading a hydraulic motor that isn't good. Maybe direct drive to a jack shaft, and chain drive from there.

cantoo: You gave me an idea, which was already starring at me on the lower drum of the conveyor, and that is using a take-up bearing on the motor side. That would eliminate the side tilting present in the photos that the single pillow block allows, if the hydraulic motor mount could be added to the take-up bearing frame guides.
What you drew is pretty cool. Not sure how you did that. Also not sure how it is different from what is already there, unless it is a fixed bearing, unlike the pillow blocks bearing that self aligns on the shaft.

I did not mess with it today as planned, although I did stare at it for awhile while waiting for a customer to come and pick up a half cord just before dark. It may be possible what I have will work if I slot the pillow block mounting holes on the inboard side of the drive drum so that it 'floats' a bit, if the pillow blocks on either side of it are adjusted for belt travel.

 

[ChoppyChoppy]

I'll get photo of my setup before I leave the shop. Hopefully will be visible, kinda dark out there.

Is it possible to remove the adjusters and put them at the bottom of the belt? Would make it much easier not having to deal with the motor AND the adjusters.

If there is just 1 adjusters, how do you tension the belt?

 

[kevin j]

I would weld the motor mounting plate to the same sliding plate that supports your bearings so that the motor plate moves as you adjust to take up. If you have pillow blocks just put a flat bar with two bolt holes in it between the frame and the pillow block bearing so it would move with the bearing and shaft. I definitely would put a Lovejoy or Magnalloy flexible coupling between the motor and the conveyor shaft though

 

[Sandhill Crane]

I too will get more pictures today. Different angles of the top adjustment as is, and the lower adjustment. In the past, I have never adjusted the top end after it is set up and running. Two or three times a year I might adjust the lower take-up bearings a turn at most. Probably temperature related, just guessing. Early on when new I expect there was some belt stretch. I bought it almost new, as in used very little, but three years old.

The motor mount is on the same sliding unit the bearing is on. The adjustment is tube-in-tube, and that is a very sloppy fit and allows the side tip. The second picture shows the mount, and the fourth picture shows the bracket. The adjustment bolt pushes on the 1 1/4" x 1 1/4" tab welded near the motor mount. In the fifth picture, the rub spot for that adjustment bolt is round on that tab.

There are adjusters, take-up bearings, on the bottom drum. The reason for top drive, as I understand it, is that the top drum pulls the load up the conveyor. If the bottom drum was powered tension would be on the return side of the belt below the conveyor. The return side has many small idler rollers that do not have bearings. Tracking also would be harder to maintain, as the load is in some ways being pushed up hill, but not really. Many chain conveyors are bottom powered however.

More rain today so probably will not mess with it, but I'll get some better pictures if nothing else. I did find take-up bearings are $65. ea. at Grainger. The slide assembly for them is another $65. ea. If I go that route I'll probably just get one and use the pillow block on the other side, $9.00 ea.

 

[Stihl310]

Is the the setup that broke?

Or is this how you fixed it? I would get rid of the double pillow blocks. You're trying to line up too many holes with that and no matter how easy they slide in there you're still going to be side loading the input shaft to your head roll unless you go with a ground plate, which is way out of scope for something like this.

I know you have a love joy in that pic so if it's your fix it should help. In the first pics with the broken motor it looks like your pillow block bearing failed along with the motor shaft. The coupling used in that pic looks to be a straight shaft coupling that isn't good for misalignment.

Basically you need to make sure you're not side loading that pump shaft, any kind of breaks like that are typically from side load. Although you could be sending too much torque through it, but I'd say side load is what's happening.

We always tell new engineers "Only God can align three holes " [emoji4]

Sent from my iPhone using Tapatalk

 

[Sandhill Crane]

Stihl310: No that is not the photo of the original set-up. Post #1, photo #1 is the original set-up. Shaft is adjustable in/out (or length ways in relation to the belt) for belt tracking. Each side is independent of the other, and shaft alignment is self aligning with bearings via pillow blocks. Motor mount/pillow block mount is shown post #1, photo #4, two bolt holes for a single pillow block.
The double pillow block on one side solves one problem, vertical alignment of motor to drum shaft, but not the other issue which is horizontal alignment with the drum shaft. It also creates a third issue of aligning three pillow blocks and maintaining movement for belt adjustment.
Not sure how it ever worked for so long to begin with, with the solid coupling.
If I remove the inboard pillow block the weight of the motor tips the motor mount outwards at the top, as shown in post #1, photo #1. The only thing that aligned the motor to the drum shaft is the solid coupling. One inch of that shaft is still in the coupling.
The question is...how does the motor stay in alignment with the drum shaft.
I'm thinking the two sides need to be connected, with a pivot on each side. That way the motor mount is in line with the shaft regardless of adjustment of either side. Example: Set a ruler in front of you on the table cross ways. Place you index fingers at 1" and 11"s. Push with one finger. Everything is still in alignment, just shifted.
Another thought is a universal with a slip yoke.
And maybe just the love joy if I can support the motor from sagging.
I'm getting closer to just bolting it up and running it 'as is' until it needs fixed again. Not sure how much alignment a love joy will compensate for.

More pictures as promised:

 

[rancher2]

I am surprised that the motor will run slow enough that it was direct drive from the motor to the belt with no chain sprocket set up to slow it down. I think I would forget the love joy and go with a u joint set up that would slide on to the motor shaft and the other end on the drum shaft. That should help with breaking the shaft again. You will probably have to remake the motor mount a little and may have to cut the shaft off on the drum to get enough room to fit the u joint coupling in.

 

[kevin j]

-The pillow block needs to be closer to the drum to reduce bending stresses in the shaft
-The tube in tube slop allows the pillow block to tilt. That doesn‘t matter to the bearing, except if it takes the motor with it.
- I would cut off the tube in tube, and use a plate alongside a channel, with bolts and slots. Sort of like a chainsaw tensioner, you want the tensioner to move the bearings, but then tighten something up metal to metal and not have any clearances. With the slack, it will always tilt, and with the slop it will move around under loads and make it harder to train the belt.
-U joint, no. They take angular misalignment but don’t accommodate any axial or any offset misalignments, so it would still put side and axial loads on the motor shaft.

 

[Sandhill Crane]

It would need two universal joints to work, and the shortest I found for a 1" shaft is 5", x 2.
As for direct drive, it is a low speed/high torque motor. There is also an adjustable flow control near the valves for belt speed. I generally run it quite slow, or 1/3 of maximum flow, and the GX 160 at 3/4 throttle. Full flow is a pretty good clip and flings the wood. That just seems like unnecessary belt and component wear.
It may be several days before I can turn my full attention back to this.
As is the drum and shaft need to shift left 5/8-3/4 inch or so to center the drum and bring the drum shaft closer to the motor shaft.
The motor needs to be removed, to remove the love joy half coupling. Replace motor, align, pull motor and install love joy.
Then give it a try.

However, as I'm typing I'm beginning to think two universals may be the way to go, like a pto shaft. Eliminate the third pillow block which just shifts the stress to the drum shaft.
It would mean moving the motor mount out 8" or so, and could be done by bolting an extension to what is already there. Problem solved.
Universal joint at Surplus Center, about $30. ea.

 

[H-Ranch]

If you do use u-joints make sure they are "in phase" (the cross should be mounted parallel on the driveshaft, not perpendicular.) Also you should not perfectly align the two shafts - u-joints need a slight angle so the needles will rotate. Not a problem on a car since it is constantly changing over the road surface, but fixed machinery may not change as it is used. The shafts should be parallel but not on the same line.

 

[ChoppyChoppy]

I am surprised that the motor will run slow enough that it was direct drive from the motor to the belt with no chain sprocket set up to slow it down. I think I would forget the love joy and go with a u joint set up that would slide on to the motor shaft and the other end on the drum shaft. That should help with breaking the shaft again. You will probably have to remake the motor mount a little and may have to cut the shaft off on the drum to get enough room to fit the u joint coupling in.

Low flow pump or large motor, or combo of both.

 

[ChoppyChoppy]

Looking at those pics, I think I'd chain drive it.

Weld the motor bracket onto something that isn't adjusting, sprocket and chain setup. That will allow the drum to be adjusted on the other side and any twist will be fine, chain isn't that precise. A lovejoy will self destruct fairly quickly with running at an angle. They aren't meant for that. Granted in a low rpm deal like that might be ok for a while.

U joints will work, but you'll have the motor hanging way out.

Seems that a chain and paddle conveyor is much easy to deal with.

Other option is go with the solid coupler and just the motor float. Just need a tab for it to catch to keep it from spinning.
Mine has a plate the motor is bolted to, that plate loosley keys into a slot. Seems to work ok, have about 1300hrs on it. Have had the coupler come loose and shear the key, that's about it.

 

[T. Mainus]

Took some pictures of the top end of our Automated Biomass conveyor for you.

 

[Sandhill Crane]

H-Ranch:
The U-joints arrived yesterday. Each yoke is the same. Using two with the spline lined up, the cross would be "in phase". So I think this may work. But then it seems the same as a single U-joint.
No photos because the phone memory is full. Crap!
Edit: I thought I'd use a short splined connector and let one side float. The two U-jounts together are 10" long. 1" of shaft on each end pushes the motor out 8-8 1/2". I could reduce that by eliminating the out board pillow block and shortening the drum shaft several inches.
For now, still being pulled in other directions, helping our son.

 

[H-Ranch]

Sorry my description was poor. The joints should be lined up like this:

If you have a commercially built shaft it should be correct already. Good luck with your modification.

 

[kevin j]

If you use U joints, they need to have a designed in offset of about 3 degrees minimum, so the internal needles roll back and forth about one circumference. If it is closer to straight, the needles rock back and forth and don’t develope a lube film and will brinnell little tiny channels in the races.
U joints sure make it long and moved out, and I don’t understand the goal.

I think you are over thinking it with the u joints and shaft. Look at any industrial conveyor and the normal practices are:
1. Hollow shaft motor directly on the head pulley shaft, with a torque arm. I know you already have the motor so this is out.
2. Motor with rigid coupling, like you had before, but motor floating and a long torque arm to resist the motion. Longer torque arm is better than short, for less side load on the bearings in motor.
3. Most common by far, motor on bracket mounted to the plate the bearing is on, with single flex coupler between them.
4. Takeup is usually at the idler end, as it appears you have in the pics. So you only need a very small amount of adjustment, probably less than an inch, at the head end, only for belt training. You can probably get that on the side opposite the motor.

The original fatigue failure was due to rigid coupling, too many bearings, and too much slop in the mounts which allowed torque loads to side load the motor and shaft.

 

[muddstopper]

Any hyd motor I have ever seen that had any amount of side load, usually have very good bearing or are mounted on a OHLA type adapter. http://www.surpluscenter.com/Power-Transmission/Bearings/Overhung-Load-Adapters/ The motor shaft slips into the adapter shaft which is supported with heavy bearings. I have seen hyd motors mounted this way that have ran for several years, day in and day out and never fail from leaking seals or broken shafts. Now that I think about it, I can only remember one of the adapters failing in over 40 years and the bolt holes broke out on that one, and that was because it was ran loose. Those little 5/8 or 3/4 inch shafts on those rotor motors aint going to hold up long with any side loading. Heck I have broken the shafts trying to knock the coupling off and I wasnt beating on it with no sledge, more like tapping with a claw hammer. After looking at how the motor is mounted on the conveyor, I think I would very much consider paying the price for the OHLA, it will mount in place of the motor bolt holes and the motor would mount into it, no cutting, welding or drilling, and you would eliminate any side loading on the motor. You probably would never have to replace another motor in your life time.