Best way to mount a trunion Hydraulic cylinder??

[Nutz4sand]

OK been trying to get to my bender stand when I can to work on it (Will post some pics soon of the frmaework.) But I am at a point where I have some ideas but am looking for maybe better ones.

I am using a trunion mount hydraulic cylinder on my PT-105 bender and looking for advice and ideas that may be better and easier than what I have come up with. I will wait to see whats said first.

Basically I will be mounting this cylinder and looking for ideas on how to attach to the trunion pins on the cylinder. Should I just put them in greased polished steel holes? Get bronze or brass bushings? Find Tapered bearings that fit (if I can) and make holes in the mounting steel for the tapered races?  What say you? How do you think would be best to mount this cylinder to allow it to pivot and not gall it up under bending loads? It will only be pivoting about 15 to 20 degrees max.

I took pics with flash and not so it could be seen as best as possible.  Thanx Bill

[artie on edge]

Hi Bill, talking without knowledge of the item in question so please take this with a grain of salt.

Im unsure of the actual loads applied to the trunnion when bending, do you think a roller bearing would take it?

Thinking of the KISS principle , as it will see limited rotation for limited periods, I cant see why steel on steel greased would be a problem.

IMO   

[fabr]

steel on steel with a well placed zerk.

[Nutz4sand]

Im unsure of the actual loads applied to the trunnion when bending, do you think a roller bearing would take it?

Thinking of the KISS principle , as it will see limited rotation for limited periods, I cant see why steel on steel greased would be a problem.

IMO   

I am thinking simple too. But not sure if a bushing would be a good idea or just steel on steel.

As for the bearing I would not use a roller bearing (to me thats a round ball bearing. Nice for low friction but not a major load bearing usually (unless HUGE!))
But I was thinking a tapered roller bearing. The tapered rollers are longer and have MUCH more surface area than regular roller (ball) bearings at a cost of a bit more friction (not a problem here)

Tapered roller bearings hold the front tires on cars and big heavy cars that weigh 2 to 3 tons. Toss in cornering loads and potholes and jumps (cause you have seen cars jumped!!) the tapered roller bearings can deal with some SERIOUS loads.

 I could only imagine how many tons of force a full size Chevy Caprice or Truck bombing across curbs and what not puts on those bearings.

I am guessing the tubing I will be bending will never get near those loads. My hydraulic system will not get past three tons. But with smaller mini buggy tubing I do not see that as an issue.

Worse comes to worse I can add length (via an attachment) to the moving bender arm for bigger thicker tubing.

Steel with a grease zerk is likely. But a bushing may find its way. Not sure waht bushing material would be best. Still looking into that and thought maybe someone had insight already?

Thanx Artie and Fabr for the replies so far.   

[fabr]

Ball,roller,needle bearings will not be a good idea since the bender will be doing only an oscillating motion .That will lead to brinnelling of the race since the rollers will only travel in short arcs.Stay with the steel on steel with zerk.If you cab;t position a zerk where it will inject grease on the load side of the trunion then utilize an annular groove to channel it there. 

[artie on edge]

Ball,roller,needle bearings will not be a good idea since the bender will be doing only an oscillating motion .That will lead to brinnelling of the race since the rollers will only travel in short arcs.Stay with the steel on steel with zerk.If you cab;t position a zerk where it will inject grease on the load side of the trunion then utilize an annular groove to channel it there.

+1 Tapered roller bearing used in the steering pivots of most 4wd (ie landcruisers) wear very quickly into a groove patern, design to roll not oscillate.

[BDKW1]

This is what I did a few years back. Bushings are highly over rated.
 

[Nutz4sand]

BDKW1 How does that pivot? Its a tad dark and I cannot tell just what pivots where or whats what so much.
Got a pic from the top maybe? That might help. Thanx Bill

[fabr]

This is what I did a few years back. Bushings are highly over rated.
 

What are you saying?

[Rick S.]

Use oilite bronze flange bushings. If anything wears you need it to be the bearing. Not your cylinder's trunnion shafts or the trunnion blocks.
The bearings can easily be replaced. I have designed using large trunnion mounted cylinders for years. I've never seen it done any other way on production assembly equipment.
This device installs the rear combine wheels. (Trunnion mounted rotate cyls with oilite bushings.)