Pillowblock Bearing question

[woodlandfarms]

I am working on this whacky idea. It is on paper only at the moment....

Here is the question. Can a pillowblock bearing be put on its side and operate safely. the idea I have involves a shaft that is rotating horizontally with some (100lbs) of weight on it, then tilts vertically, onto its side...

Any thoughts?

 

[scgargoyle]

I'd find out from the manufacturer. Some pillow blocks are designed for significant thrust loads, some aren't. Any decent bearing should have specs available. 100 lbs. isn't a real lot, depending on the size of the bearing. Building your own Tilt-A-Whirl?

 

[KYErik]

Depends on the speed of rotation as well. If that 100 lbs was rotating at 3000 rpm and then the assembly was tilted quikly- there would be lots of gyroscopic force involved and significantly more bearing stress.

For 100 lbs, I am thinking that you need at least a 1'' shaft/bearing if its going to do over 100 rpms.

 

[GinNB]

I'd say yes, but it'd depend on the length of the shaft you have the 100lbs on, the size of the shaft, the rpm of the shaft, and how fast you want to elevate it. Also, most pillowblocks allow the bearing to pivot in the block, so if you want to rotate the block and have the shaft follow the block then you'll need two pillowblocks on the shaft and rotate the plate they're mounted to. Do you just want to use the amount of play that's available in the block? I mean by mounting the block solid and tilting the shaft (and bearing) a bit? Even if you use two blocks and rotate the plate from horizontal to vertical, the entire 100lbs on the shaft with be suspended on the 4 set screws (two per block), so you have to take that into account if the shaft is belt/chain-driven as well as the side loads on the pillowblock bearings. If it's not belt or chain driven, then the vertical load on the set screws will be shared with however the shaft is mounted on the motor. In other words, it's not just the sideloads on the pillowblock bearings you have to worry about. Care to share more details of what you're trying to do?

 

[woodlandfarms]

I have a PT, so think of it as a Bobcat type of tractor....

I am mulling over making my own stump grinder. One that has a few tricks up its sleeve. My tractor is all hydraulic. I am planning on a 300 to 500 rpm motor direct driving the grinder head.

The tricks would be that the head could be rotated (manually, by removing bolts) in 3 different directions. Forward, like a normal chipper, sideways like this chipper Stump Grinders/Stump Cutters, and horizontaly with the motor on top. This would serve as a brush cutter, small stump grinder.

The disc would be around 24" of 1/2" steel and cutting teeth. I really guessed on the weight issue.

Initially my design was to have this wheel attached and supported only by the motor, but the more I studied other designs it began to look to me like that it would be a lot of stress on the motor...

Again, I am about 3 months away from even thinking of trying this project...

 

[Mickey_Fx]

Pillow blocks come in several designs and how much laterial load they can support will depend upon the design and how the shaft is retained on the bearing.

Many pillow block bearing housings take std ball bearings with a spherical OD. Also common is the shaft is locked to the shaft with a rotating collar held in place by a set screw.

For a stump grinder there will be applied side loads so you need a design that can handle larger loads than just the weight.

Bearing capacity will depend upon bearing size and design. Some BB's are designed to handle higher side loads and the typ BB (see pics). I'm also thinking it is going to take better support than a twist lock collar with a set screw to handle the side loads.

 

[Danno1]

.

They won't last very long. There will be a lot of shock loading.

You need angular roller brgs as in the disk brake rotors in a car.

.

 

[woodlandfarms]

Cool.. Now I see what you are talking about.

Of course today I saw a dead grinder. Motor was conked but the hydraulics solid. May be a $400 purchase and just rig it to the PT...

But, keep the ideas coming. I am not the only one hunting on craigslist.

 

[Highbeam]

Just buy a brush hog gearbox and utilize the output shaft to mount your blade, input to the hydro motor, and support from flange.

 

[woodlandfarms]

Just buy a brush hog gearbox and utilize the output shaft to mount your blade, input to the hydro motor, and support from flange.

OK. This is an excellent idea I have been mulling over. My only question is why do I need the gearbox? Isn't it just an added expense when I can get a hydraulic motor to go at any speed I want?

I hope this does not come off strongly, not my intent. I am just trying to take in your idea (or actual result?) and fold it into my plan.

Gearboxes I have seen are fairly expensive. Any sources you might recommend?