Calculating leadscrew efficiency?

[roozle]

I am trying to find out the efficiency of a leadscrew assembly.

I am using a acme thread with an outside diameter of 0.67" and a pitch of 0.1575". The leadscrew material is AISI 416se and the nut is Phosphur bronze PB2. I have load of 1200N.

Can anybody shed any light on this??

Thanks,
Roozle

 

[ecampos]

Should be
e=FL/2PiT F-linear force
T-Torque applied
L-Lead (tan alpha=L/Pid
alpha= thread angle
d= mean diameter of screw
This is from "Mechanical Engineering Design" Shigley and Mitchell [ISBN 0-07-056888-X}

Hope it helps.

Edson Campos
edsoncampos@earthlink.net

 

[GregLocock]

That's the effort, not the efficiency!

I'd start by looking at the likely coefficient of friction, and the load on the thread, and the sliding speed. This would give the power consumed in friction. You knwo the power going in, torque times rotational speed in approriate units, so you can work out the efficiency.

Finding the coefficient of friction might be the hardest bit, but it isn't impossible to measure it.

Cheers

Greg Locock