CAD CAM EDM DRO - Yahoo Group Archive

Re: Belt tensioners on toothed belts

Posted by Chris Horne
on 2006-07-29 14:44:10 UTC
The error introduced is directly related to the slackness of the belt,
the diameter of the pullies and the screw pitch. For acme threads it
will be negligible and I don't think it is worth bothering with
tensioning at all, for ballscrews the error would be more significant.

IMHO a better solution than sprung idlers or moving the motor would
be adjustable, but non sprung idlers. A couple of bearings (depending
on the size of the belt, cheap skate bearings would do) on a sliding
mount would be my prefered method

Chris


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "caudlet" <thom@...> wrote:
>
> I just finished helping a customer with a servo driven plasma table
> and I was surprised to see spring loaded idler wheels on swing arms
> (like the old reel-to-reel tape drives) being used to tension the
> belts on the toothed pulleys. The tension mechanism was a coil spring
> and was not very taunt so that when the motors changed direction the
> belt would bow out or in, depending on the direction. Seems to me the
> flexing of the belt would introduce some errors. Do any of you have
> any experience with a design of this type? Seems like a way to move
> the motor to maintain belt tension would be a better approach. I
> guess if the belt tension was strong enough it might be a better
> solution (?)
>
> I do know that in this circumstance it ended in disaster. The pivot
> arm became loose and the arm got cocked at an angle. It was okay with
> the axis running in one direction but it acted almost as a brake in
> the other direction and since the motors were large it just ran until
> the fuse blew (about 30 msec after the servo drive blew!).
>
> Tom Caudle
>

Discussion Thread

caudlet 2006-07-29 14:24:35 UTC Belt tensioners on toothed belts turbulatordude 2006-07-29 14:42:14 UTC Re: Belt tensioners on toothed belts Chris Horne 2006-07-29 14:44:10 UTC Re: Belt tensioners on toothed belts Tony Smith 2006-07-30 00:39:11 UTC RE: [CAD_CAM_EDM_DRO] Belt tensioners on toothed belts Ken Campbell 2006-07-30 04:34:31 UTC Re: [CAD_CAM_EDM_DRO] Belt tensioners on toothed belts caudlet 2006-07-30 11:00:16 UTC Re: Belt tensioners on toothed belts Chris Horne 2006-07-30 11:24:49 UTC Re: Belt tensioners on toothed belts R Rogers 2006-07-30 11:48:07 UTC Re: [CAD_CAM_EDM_DRO] Re: Belt tensioners on toothed belts ballendo 2006-07-30 17:46:04 UTC Re: Belt tensioners on toothed belts ballendo 2006-07-30 17:46:07 UTC Re: Belt tensioners on toothed belts ballendo 2006-07-30 17:49:36 UTC Re: Belt tensioners on toothed belts caudlet 2006-07-30 20:34:10 UTC Re: Belt tensioners on toothed belts ballendo 2006-07-30 21:13:53 UTC Re: Belt tensioners on toothed belts tppjr 2006-07-31 17:08:01 UTC Re: [CAD_CAM_EDM_DRO] Re: Belt tensioners on toothed belts