[CAD_CAM_EDM_DRO] rack & pinion refinements
Posted by
ptengin@a...
on 2001-07-02 23:27:37 UTC
In a message dated 07/02/2001 4:17:18 AM Hawaiian Standard Time,
peteryco@... writes:
I just wanted to point out that a helical cut rack gets rid of most of the
speed oscillation. If you use a herringbone gear setup, there is no end
thrust problems as with plain helicals. You will still have the backlash
problem but that can be solved with tandem drive gears on each rack. Perhaps
a HPT belt driving two jackshafts, the center distance being adjusted to give
a slight preload. Note that this would not be to save cost over a
ballscrew/nut setup but to allow for extremely long and accurate travel.
[Non-text portions of this message have been removed]
peteryco@... writes:
> Like when you have a chain drive with small sprockets the polygonSven & group,
> effect makes that the chain gets tensioned end loose.
> The rack and pinion construction will have a speed oscillation which
> becomes worse as smaller the the pinion is.
>
>
I just wanted to point out that a helical cut rack gets rid of most of the
speed oscillation. If you use a herringbone gear setup, there is no end
thrust problems as with plain helicals. You will still have the backlash
problem but that can be solved with tandem drive gears on each rack. Perhaps
a HPT belt driving two jackshafts, the center distance being adjusted to give
a slight preload. Note that this would not be to save cost over a
ballscrew/nut setup but to allow for extremely long and accurate travel.
[Non-text portions of this message have been removed]