Re: [CAD_CAM_EDM_DRO] Re: Bearing mounting revisited

My two bits...

I would have thought that using the ballscrew/leadscrew to take up the axial
load along it's length would be open to all sorts of problems.

Unless the machine is quite small, you're going to get some neat effects
with thermal change, as the screw would be "clamped" between the two end
mounts, and attempt to bow the bed when it was hot/cold depending on the
different materials needed. Given that typically the difference between
preloaded and stalled for a bearing is .002-.010" or so it'd not take much
over a 1 yard screw for example... Hence the reason many designs use a
simple bearing support at one end to allow some movement.

Cheers, Chris.

* Design engineer, Assembly worker, Cleaner.
* Ohmark Electronics. PO Box 5302, Christchurch, New Zealand.
* http://www.ohmark.co.nz

----- Original Message -----
From: Smoke <Smoke@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Saturday, October 28, 2000 10:31 AM
Subject: Re: [CAD_CAM_EDM_DRO] Re: Bearing mounting revisited


> Yes and no...depends on the type of bearings you use. If you use non
separable bearings, you won't need the extra retainer...the inner race is
stopped by the step on the bearing shaft (assuming the opposite end of the
shaft can't move lengthwise)...the outer race is stopped by the retainer as
drawn. If you use bearings where the races will come apart...like Timken
bearings, then you would have to add a retainer for the outer race. This
retainer could be identical to the other retainer (depends on bearing
design). In any case, all fittiing can be done on the one part.
>
> By the way....as some one pointed out...its a good idea to fix the bearing
assembly so it can't move up, down or sideways after installation. This can
be done using dowel pins thru the housing/retainers at assembly.
>
> Smoke
> -----Original Message-----
> From: Hugh Currin <currinh@...>
> To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
> Date: Friday, October 27, 2000 1:14 PM
> Subject: [CAD_CAM_EDM_DRO] Re: Bearing mounting revisited
>