Re: [CAD_CAM_EDM_DRO] Ballscrew end mounts was Re: Doesnt ANYONE have this drawn up???

Wow, now thats data.! You probably did say DXF but I spaced it.
I'll check it out. Thanks Les! Your spoiling me.. :)

Vince

----- Original Message -----
From: "Leslie M. Watts" <leswatts@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Sunday, August 17, 2003 5:53 AM
Subject: RE: [CAD_CAM_EDM_DRO] Ballscrew end mounts was Re: Doesnt ANYONE
have this drawn up???


> Vince,
>
> I think you may have the wrong one....
> The file name is endbearing.DXF.
>
> It is not highly detailed but is to scale. I have
> dimensioning turned off.
>
> The main purpose with this is just to show exactly how
> the commercial units are constructed. This one is 17mm
> bore, but others might be different depending on ballscrew
> size.
>
> In this design (as is typical) steel bearing retaining rings
> also serve as replaceable seal mating surfaces. Locknut torque
> is not terribly critical because the bearings are universal flush
> ground for a light (5%) preload. This simply means that the bearing
> inner rings are actually very slightly recessed compared to the
> outer ones. When the locknut is tightened the inner rings
> of the pair deflect until they come in contact. The deflection is just
> the proper amount to give that specified preload. Further
> tightening of the nut does not increase the preload any further.
>
> One has to hunt up bearing fit tables for the exact housing
> bore and shaft diameter dimensions.
>
> Here are numbers for 7203 from the MRC bearing engineering
> handbook:
>
> shaft: 0.0000"-0.0007" interference in bore ABEC-1
> 0.0000"-0.00035" ABEC-7
>
> housing:
> 0.0000"-0.0011" loose ABEC-1
> 0.0000"-0.00055" loose ABEC-7
>
> I find ABEC-1 is fine for most ballscrew setups.
>
> Bearing contact angle can be 15-40 degrees depending
> on load requirements. Many even use deep groove bearings
> with a higher than normal radial clearance. This causes them
> to actually operate as angulars with a few degrees contact angle.
> Several machines in my shop use this as an economy measure,
> but shims or spacers must be used since deep grooves are not
> normally supplied with universal flush face grinding. I prefer
> 40 degree angulars for ballscrews though.
>
> A final note: for this size range it is reccomended that
> the bearing bore/shaft interference be limited to 0.0002"
> to facilitate assembly and disasembly without possible
> damage to the expensive ballscrew. The upper ranges of
> the fit tables don't really consider this, and the bearings
> can be almost impossible to remove without damage in
> this kind of assembly.
>
> Les
>
> Leslie M.Watts
> L M Watts Furniture
> Tiger Georgia USA
> http://home.alltel.net/leswatts/wf.html
> Engineering page:
> http://home.alltel.net/leswatts/shop.html
> CNC surplus for sale:
> http://home.alltel.net/leswatts/forsale.html
> CNC carved signs:
> http://home.alltel.net/leswatts/signwp.html
>
>
>
>
> -----Original Message-----
> From: Vince Negrete [mailto:vnegrete@...]
> Sent: Sunday, August 17, 2003 12:30 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] Ballscrew end mounts was Re: Doesnt
> ANYONE have this drawn up???
>
>
> Oh that one? Here lemme copy name here...
>
> Simple Shaft Bearing Mount.JPG
> An easy way for mounting and adjusting shaft bearing supports
>
> Is this the right one?
>
>
>
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