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

Simple driveline torque measurement method ? Horsepower also.

Simple driveline torque measurement method ? Horsepower also.

(OP)
If the torque output of the differential output shafts is always the same - then if one shaft is locked in a simple scale/lever device (to measure the shafts torque at zero rpm) and the other shaft is connected to a load and allowed to rotate - then the torques will be the same.

Also -by measuring the rpm of the rotating shaft the horsepower can be calculated.

Anybody see any problems with this?

This must have been done a hundred years ago!

RE: Simple driveline torque measurement method ? Horsepower also.

vibratory effects may make your calculations more difficult, but it ought to (roughly) work.

RE: Simple driveline torque measurement method ? Horsepower also.

I do not believe that the torque will be shared equally between the two shafts.
Usually if you lock up one shaft, the speed of the other shaft will increase.

Ron Volmershausen
Brunkerville Engineering
Newcastle Australia
http://www.aussieweb.com.au/email.aspx?id=1194181

RE: Simple driveline torque measurement method ? Horsepower also.

Gearcutter is correct; the free shaft will run at double speed. ... and half torque. ... well, less than half torque because of friction within the diff.

Worse, the typical bevel differential gears don't have real bearings or effective cooling, so they'll overheat and fail pretty quickly when used in the way described.

The usual lowbuck (sort of) tactic is to instrument the engine mounts to estimate torque developed.

Mike Halloran
Pembroke Pines, FL, USA

RE: Simple driveline torque measurement method ? Horsepower also.

uh, you sure about that? I'm guessing you mean "half of the total input torque" not "half of the torque measured on the other (fixed) shaft?"

RE: Simple driveline torque measurement method ? Horsepower also.

The basic premise is sound. The aftermarket can provide roller-element bearings of some popular differentials. I've built such 9" Ford differentials, since my pulling tractor needed an efficient/rugged fully "open" differential to allow steering via independent rear brakes. Needle bearing spider gears and needle bearing thrusts for the side gears can be sourced.

RE: Simple driveline torque measurement method ? Horsepower also.

That's basically an inertia dyno and it is fraught with difficulty because of that, and because a diff typically has a lot of friction and hence is not especially accurate at providing each shaft with equal torque.

The oil temp will change rapidly during the test which will alos affect the results.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Simple driveline torque measurement method ? Horsepower also.

The original poster talked of applying load, measuring RPM, and calculating power; this implies "brake" dyno operation, not "inertia" type. As for high differential friction, see my 28 March post.

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