INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Gearbox Wind-Up Torque/Force

Gearbox Wind-Up Torque/Force

(OP)
On a gearbox for a pump, the torque should be higher on the low speed side (the pump shaft) than the high speed side (the motor). I'm sure this is true for a steady state system. On startup, shutdown, or anytime the system undergoes a transient response (say the pump shaft is quickly torqued while the pump is not running, is this still true? Take for instance the following example:

-Pump is not running. There is an anti-reversing clutch mounted on the motor shaft to prevent the motor from spinning backwards and damaging components.
-Something quickly torques the shaft in the reverse direction.
-Before the clutch will stop the reverse motion, all the free play in the gearbox must be removed, so the pump has the chance to speed up for a short time.
-Finally, after all slop in the system is gone, the clutch starts seeing torque and stops the pump from rotating.

If the clutch was mounted directly on the pump shaft, is it possible that the torque would be lower because there is not as much slop in the system that would allow the pump to accelerate?

RE: Gearbox Wind-Up Torque/Force

When you say 'the torque', you have to be specific about which torque you're discussing.

If you put a no-back clutch on the output shaft, then the motor would see little or no torque under circumstances that would engage the clutch. ... but the torque involved would be larger by the gearbox ratio, and you would need a proportionately larger clutch. ... which might engage more slowly because of its mass.

The _exact_ answer to your hypothetical question requires consideration of a lot of information that is not available to us, but that was probably available to, and considered by, the gearbox engineer.

Do you have an actual gearbox with a problem, or are you just ruminating?

Mike Halloran
Pembroke Pines, FL, USA

RE: Gearbox Wind-Up Torque/Force

(OP)

Quote (MikeHalloran)

Do you have an actual gearbox with a problem, or are you just ruminating?

The discussion was a theoretical discussion on whether a no-back clutch (such as a Ringspann clutch) would see the highest loading if mounted on the output shaft, an intermediate shaft within the gearbox, or the motor shaft. I looked through the Ringspann article and it clearly is a complex problem that is often miscalculated. At this point I'm not trying to calculate actual peak loads, but just understand whether it is likely that the torque would be higher on the output shaft, or somewhere else in the system. I suppose it depends on a lot of factors, including gear ratios, stiffness of the components, clearances between gear teeth, and the profile of the load applied.

RE: Gearbox Wind-Up Torque/Force

Hi

I would say the maximum torque (peak) would occur at the point of loading, so lets say the pump impeller jammed instantaneously, then the motor via the gearbox would try to keep the pump turning and down stream from the pump impeller all the mechanical components like shafts and gears would suffer wind up until such time the brake or cutout/ slipping clutch kicked in.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close