Re: Fine-pitch allthread? Harmonic gears

Posted by turbulatordude

on 2003-07-04 07:59:40 UTC

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jeff Demand <jdemand@a...>
wrote:

> Marv,
>
> Very correct but I wasn't suggesting multi start threads. After

seeing all

> sorts of other distractions the best explanations I found was at
>

http://www.dewtronics.com/tutorials/lasers/leot/course06_mod02/mod06-
02.html

> Have to scroll down a bit and ignore the fact that this example

uses 40

> and 30 TPI threads ;-)
>
> Jeff

The explanation seemed very simple, and I immeadiatly thought of
using a larger OD screw with a taped bore so the unit would be more
compact.

A 28 and 20 tpi combination will yield a movement of 0.01428 and a
40tp will yield a movement of .025, so the combo offers a finer
thread but it also offers much more strenght.

They make a gear reduction that works in a similar way. a pair of
internal toothed gears that have different teeth. the drive gear
rotates, rotating the small internal spur gears that in-turn rotate
the drive gear.

super high gear ratios of over 10,000:1 are possible. could offer
possible use in high power, low speed devices.
http://www.harmonic-drive.com/gearcomp.html

I can't remember the NASA technology transfer paper I read that in.

Dave

>
>
>
>
>
> -
> Jeff Demand
> Modeling Solutions
> http://www.aztec-net.com/~jdemand
> -

Discussion Thread