Sizing Shaft Diameter 1

[amarks]

Looking for some help on sizing the shaft diameter for a winch drum. I've worked the equation attached from Shigley and Mischke Mech Eng Design, but the shaft size seems pretty large for the application.

Anybody have any experience designing drive shafts for winches and/or know other calculations to follow?

Thanks

 

[desertfox]

Hi amarks
Can you provide details of your shaft you are trying to size, giving us a blank formula and saying it appears to give a much larger shaft than expected doesn’t give us any information to help you.

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[dvd]

Recommend following methodology from ASME B106.1.

 

[CraneEng87]

Blodgett Design of Weldments has some good (yet old) drum design examples. We use it in the crane industry on the occasion.

 

[amarks]

desertfox - sorry about that. Attached is a picture of the excel spreadsheet I put together to calculate this. Let me know your thougths.

 

[BEMPE16524]

Are you considering anything to be attached to the shaft? Such as gearbox, bearing, etc.?
What is the purpose of your winch?
It's quite odd to have a solid shaft for that quite big winch.

R.Efendy

 

[dvd]

Not going to do any of your work, but it looks like you want to make a welded drum where the shaft welds to the end disks. You are probably going about this wrong and are going to replace or repair an expensive drum. Take a look at the attached paper for a little guidance. If you insist on proceeding, make sure you understand the ramifications of welding your (apparently) higher carbon steel shaft to the disks. You guys need to hire some expertise.

edit - your drum weight and cable weight will affect your moment calculation

 

[amarks]

BEMPE16524 - Yes, there will be drum bearings attached to the end plates on the drum and pillow block bearings attached to the frame for the drum shaft to spin on. The drum is going to be chain driven by chain and sprockets connected to a planetary gearbox. Purpose of the winch is to pull conductor lines through towers and poles.

dvd - We won't be welding the shaft to the drum. Thanks for the paper, has some good information. We've built a lot of drums, just not to this scale.

 

[desertfox]

Hi amarks

Just having a Quick Look at your calcs and they seem okay to me. I will study it in more detail and shout up if I see anything. Thanks for the update

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[dvd]

We won't be welding the shaft to the drum.

be aware of shaft locking devices and bending moments - Ringfeder for bending loads

 

[dgeesaman]

B106.1 is a good method when loading is somewhat predictable.

When loads are variable it can get conservative using worst-case loads but for a winch drum I wouldn't get leaner until I was really, really sure how it will hold up.

 

[amarks]

dvd - I noticed in that previous document you sent, that could be an issue and they actually machine a raised journal on the shaft where the locking device sits to reduce these stress concentrations. Thank you for that information.

 

[dvd]

amarks - that paper was written before the advances in Ringfeder design and knowledge. I recommend a call and discussion with Ringfeder. They know their products and understand the applications.

 

[DAVIDSTECKER]

The way I see this you're applying the entire 30,000# directly to the mid-point of the shaft and using a moment arm of 45".
The drum should carry the force out to the flanges, then to shaft.
Best case loading is mid-point of the drum, 30,000 / 2= 15,000#
Worst case, all 30,000# one end, up against the flange.
Take the moment from the flange to the end of the shaft and see what you get.

 

[drawoh]

Amarks,

The last time I designed a drive shaft was very long ago. My shaft diameter wound up being controlled by the two keys needed to transmit torque from a worm gear.

--
JHG