attaching things to a motor shaft
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Posts: 46,084
hi,
I'm looking at buying wheelchair motors to use on a large robot,
but the motors I'm seeing usually have very short, smooth
cylindrical shafts. If they're just smooth cylinders, how can a
shaft extention be firmly attached to them? In general, when one
buys a motor, is it supposed to be hard to actually make use of the
motor?! (ie actually attach something to the spinning shaft). I
haven't built large robots before, so I'm kind of new to large
motors. Thanks for any help!
I'm looking at buying wheelchair motors to use on a large robot,
but the motors I'm seeing usually have very short, smooth
cylindrical shafts. If they're just smooth cylinders, how can a
shaft extention be firmly attached to them? In general, when one
buys a motor, is it supposed to be hard to actually make use of the
motor?! (ie actually attach something to the spinning shaft). I
haven't built large robots before, so I'm kind of new to large
motors. Thanks for any help!
Comments
clamp with a hex screw which tightens against a thread in the opposite
hemi-cylinder. A less secure type uses a set screw. To compensate for
shaft-to-shaft misalignment, there are flexible couplers, sometimes
called bellows, spider, or helical beam couplers. McMaster-Carr has a
good size selection. Catalog 109, page 1032, or www.mcmaster.com.
Dennis
Original Message
From: Sam [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=RGLd7rFP_LK1BwUXciPHH3tFa3WTpt9d9OVGEgRQgfq3D6d-o8yF8Xo-NIiE6lcWlqhINCNAAfwEjg]hard-on@t...[/url
Sent: Monday, November 17, 2003 3:11 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] attaching things to a motor shaft
hi,
I'm looking at buying wheelchair motors to use on a large robot,
but the motors I'm seeing usually have very short, smooth
cylindrical shafts. If they're just smooth cylinders, how can a
shaft extention be firmly attached to them? In general, when one
buys a motor, is it supposed to be hard to actually make use of the
motor?! (ie actually attach something to the spinning shaft). I
haven't built large robots before, so I'm kind of new to large
motors. Thanks for any help!
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> hi,
>
> I'm looking at buying wheelchair motors to use on a large robot,
> but the motors I'm seeing usually have very short, smooth
> cylindrical shafts. If they're just smooth cylinders, how can a
> shaft extention be firmly attached to them? In general, when one
> buys a motor, is it supposed to be hard to actually make use of the
> motor?! (ie actually attach something to the spinning shaft). I
> haven't built large robots before, so I'm kind of new to large
> motors. Thanks for any help!
Many of the better quality devices use pressure and friction to lock
things to the shaft. the shaft is not marked or nicked or any metal
sidplaced, just pressure to hold things together.
ever notice that drill bits are round on the end but you still manage
to work with them?
Flat spots are nice when one is using a serscrew, but is really
making up for the lack of a high quality shaft adapter.
in your case, feel free to file the shaft to make a place to use a
set screw.
Dave
>hi,
>
> I'm looking at buying wheelchair motors to use on a large robot,
>but the motors I'm seeing usually have very short, smooth
>cylindrical shafts. If they're just smooth cylinders, how can a
>shaft extention be firmly attached to them? In general, when one
>buys a motor, is it supposed to be hard to actually make use of the
>motor?! (ie actually attach something to the spinning shaft). I
>haven't built large robots before, so I'm kind of new to large
>motors. Thanks for any help!
Here is a resource for motor controllers that were designed for use with
wheelchairs: http://divelec.tripod.com/id1.html . On the same web site they
also offer wheelchair motors with threaded shafts and shaft keyways. Here is
the link for the motors:
http://members.tripod.com/~divelec/wcmotors/wcmotors.html .
I have dealt with this company and have always been quite satisfied.
Technical questions are always answered promptly. The prices are very
reasonable as well.
Bruce Bates
continuous) motor control, they work quite nicely. Now I have
two 'thor 885s' from the same company which can handle 24V and
120Amps continuous. They are popular with the battlebot crowd as
well (I think most of the 1st place teams use them). Thanks for the
advice on the motor shafts. I just thought it was a little weird
that one has to file them down to actually use them (in my case at
least).
--- In basicstamps@yahoogroups.com, Bruce Bates <bvbates@u...> wrote:
> At 11:11 PM 11/17/03 +0000, Sam wrote:
> >hi,
> >
> > I'm looking at buying wheelchair motors to use on a large
robot,
> >but the motors I'm seeing usually have very short, smooth
> >cylindrical shafts. If they're just smooth cylinders, how can a
> >shaft extention be firmly attached to them? In general, when one
> >buys a motor, is it supposed to be hard to actually make use of
the
> >motor?! (ie actually attach something to the spinning shaft). I
> >haven't built large robots before, so I'm kind of new to large
> >motors. Thanks for any help!
>
> Here is a resource for motor controllers that were designed for
use with
> wheelchairs: http://divelec.tripod.com/id1.html . On the same web
site they
> also offer wheelchair motors with threaded shafts and shaft
keyways. Here is
> the link for the motors:
>
http://members.tripod.com/~divelec/wcmotors/wcmotors.html .
>
> I have dealt with this company and have always been quite
satisfied.
> Technical questions are always answered promptly. The prices are
very
> reasonable as well.
>
> Bruce Bates
> hi,
>
> I'm looking at buying wheelchair motors to use on a large robot,
> but the motors I'm seeing usually have very short, smooth
> cylindrical shafts. If they're just smooth cylinders, how can a
> shaft extention be firmly attached to them? In general, when one
> buys a motor, is it supposed to be hard to actually make use of the
> motor?! (ie actually attach something to the spinning shaft). I
> haven't built large robots before, so I'm kind of new to large
> motors. Thanks for any help!
Hi:
The best way to connect to a motor shaft is using a compression type
of Power Transmission Coupling. Since you have a round shaft you
don't have much choice anyway. I do not recommend that you take a
file and attempt to put a flat on the shaft.
A compression coupling has a split collar integral to the coupling.
They come in one or two screw varieties. As the screw(s) is (are)
tightened it compresses the collar(s) on the motor shaft. I recommend
a flexible design which will provide forgiveness for and mis-
allignment.
Look in the yellow pages under ''Power Transmission'' and give a PT
shop in your area a call. Make sure you have exact diameters of the
two shafts and also the gap between the shaft ends. You should also
know max shaft speed and max (starting) torque.
If you are not concerned with position accuracy, you can select an
inexpensive type with a rubber insert. However, if position accuracy
is important, you should stay away from the insert type because they
have backlash and the lost motion will drive a servo nuts. You should
then look for a servo type of coupling.
Good luck.
Stancamp in Cincinnati
Do a web search for 'torque hubs'. Or 'torque mounting hubs'. I am not in my
office and cant remember the company that makes them. They are for mounting
gears and gearboxes to round motor shafts.
Im on a slow hotel Internet connection or I would search for them.
WM Berg Company has them and Stock Drive Components also.
Maybe try Small Parts Inc.
Hope this helps,
Alan Bradford
Plasma Technologies
In a message dated 11/17/2003 7:38:19 PM Eastern Standard Time,
hard-on@t... writes:
hi,
I'm looking at buying wheelchair motors to use on a large robot,
but the motors I'm seeing usually have very short, smooth
cylindrical shafts. If they're just smooth cylinders, how can a
shaft extention be firmly attached to them? In general, when one
buys a motor, is it supposed to be hard to actually make use of the
motor?! (ie actually attach something to the spinning shaft). I
haven't built large robots before, so I'm kind of new to large
motors. Thanks for any help!
[noparse][[/noparse]Non-text portions of this message have been removed]
has a short round shaft, that is what is required for that particular motor.
The shaft may have been specified by the original customer to drive a wheel
by friction gaining a torque advantage in that particular application. It
is not unusual in industry to adapt motors for a certain application by
grinding a flat or drilling the shaft for a set screw, drilling and pinning
to a coupler, or even splining the shaft or milling for a key if necessary.
Easiest coupler for the home hobbiest to make would probably be to find some
metal tubing that fits snugly over the shaft, drill it and the shaft at the
same time and insert a pin or bolt through the hole. The gear, pulley or
coupler would be attached to the tubing. The strength of the coupling is
determined by the shear strength of the pin or bolt used. Or, grind a flat
on the shaft for the set screw(s) of a pulley. A fine hand flat file will
work if you don't have a grinder. With a little ingenuity, and a big enough
hammer, you can make anything fit!
jim
http://www.geocities.com/jimforkin2003/
Original Message
From: Sam [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=RHfdabW03TYuM94Ikbckcna2fXPoB7yX4aSVMiSY0Me27DSEscadxtpdAcMG2FL8wD649_ntTjkianot]hard-on@t...[/url
Sent: Monday, November 17, 2003 6:11 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] attaching things to a motor shaft
hi,
I'm looking at buying wheelchair motors to use on a large robot,
but the motors I'm seeing usually have very short, smooth
cylindrical shafts. If they're just smooth cylinders, how can a
shaft extention be firmly attached to them? In general, when one
buys a motor, is it supposed to be hard to actually make use of the
motor?! (ie actually attach something to the spinning shaft). I
haven't built large robots before, so I'm kind of new to large
motors. Thanks for any help!
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hubs and lots of other things.
--
Regards
Dave Evartt
American Hovercraft