Connecting hydraulic motor shaft to another shaft

[rolo9898]

Hello,

What is the best method to connect a hyd motor shaft to turn another shaft about 1' away when both shafts are pointing downwards?

I was thinking of using a chain and sprockets, but was unsure if the chain could take 9,000 inch pounds of torque the hyd motor could put out. The sprocket on the other shaft would be welded. Felt a belt and pulley wouldn't hold up and installing three gears to get the same direction of rotation was a bit difficult to plan.

Thank you,

 

[rolo9898]

Should of mentioned the rpm's on the hyd motor is about 180-320 max. Gear ratio is 1-1 for the hyd motor and the right side shaft.

The problem is the hyd motor in/out load is about 1,000 #'s. If I transfer that load to the side I can use the right side shaft to get more weight. The side (I think its called radial load) rating on the hyd motor is about 4,000 lbs.

 

[Philrock]

At 9,000 in-lb and 320 rpm, your hyd motor is putting out about 46 h.p. At this rpm, #120 roller chain on 18 tooth sprockets is rated about 62 h.p. Chain pull would be about 2,100 lb.

You said, "The problem is the hyd motor in/out load is about 1,000 #'s." Could you explain this in more detail?

 

[rolo9898]

Thank you for the reply.

The way I understand it is if you have a hydraulic motor shaft pointing down the maximum amount of weight that can hang on that shaft cannot exceed 1,000 #'s. Same with if the motor shaft was facing up wards. Still cannot add 1,000 pounds of weight on the shaft. Gather if you hang much more than 1,000"s on the shaft it will pull out of the motor casing and if you add more than 1,000 #'s to the shaft it will break the back side of the motor case.

BTW: Is there a formula for figuring out chain and sprocket sizes? For instance the size needed for chain and sprocket in the same configuration with 5,000 inch #'s of torque.

and..... is there a problem running a chain on it's side versus straight up and down like a bicycle has?

Thank you,

 

[Philrock]

You need to confirm with the manufacturer that your interpretation of the shaft load rating is correct. You may need to know both side and thrust load ratings. In your application, the chain pull is a side load, and any weight hanging on the shaft is a negative thrust load.

Running a chain on vertical shafts is not ideal but is widely done nonetheless. With chain on vertical shafts, it's even more important to have good lubrication and keep chain slack within recommended limits.

Equations:

T = F*D/2
P = T*N/63025

where -

T = torque, in-lb
P = power, h.p.
F = chain pull, lb
D = sprocket diameter, in.
N = sprocket speed, rpm


To select the proper chain, you need to know power and rpm of the smaller sprocket, then use chain power rating tables, which are widely available on the Internet (search on "ANSI standard roller chain") and in catalogs. Apply an adequate safety factor. Do not use sprockets with less than 18 teeth - in fact, 20 or more teeth would be better.

 

[rolo9898]

Thanks, I've been able to figure out the chain size and sprocket with the info. you provided. Now I'm working on how to secure the 2nd shaft with bearings. Since it has both a side load and up/down loads it looks like it needs both a thrust bearing for the up and down weight load and roller bearings for the side load coming from the hyd motor.

It is amazing what is required to transfer a load!

The drawing is a home built hydraulic powered drilling rig. I needed to transfer the weight from pull down forces off it so I came up with the idea of transfering the carrying loads to the side shaft. It also allowed the removal of a "T" water swivel between the hyd motor and the drill pipe. By shifting the load I can put a live water swivel at the very top of the new shaft and get it out of load carrying. The rig has already drilled hundreds of feet with no problem with torque at 5,000 inch pounds, but felt the carrying load was pushing the limit.

 

[PeterCharles]

"..it looks like it needs both a thrust bearing for the up and down weight load and roller bearings for the side load.."

With a bit of luck you may be able to use simple single row deep groove ball bearings to handle both the axial and radial loads. You just need to work out the numbers.

 

[rolo9898]

Thank you,

I looked at the deep roller bearings and the specs did mention both high radial and thrust load capability.

I like the 4 bolt flange bearings since they have such a large mount area and appears they may be the deep groove. type. I will have to research them in depth because though finding the right bearings is important they still have to be mounted.