Photos would be handy here. John -----Original Message----- From: Chris Albertson [mailto:albertson.ch...@gmail.com] Sent: June 26, 2023 9:59 AM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Drilling holes in the back of a stepper motor
I�m working on the same kind of thing. I want to add an encoder to a BLDC drone motor and we don�t have much shaft length at all. The design �secret� is to realize that you do NOT need a plate or any material at all between the motor and the encoder. You can support the encoder from the rear. Make a 5-sided box housing that fits over the end of the motor and the encoder attaches to the inside of the box and also to the extended shaft. he encoder does not even need to touch the motor housing. Or maybe you only use locator pins in very shallow holes in the motor. 3D printers and CAD software make this made of complex parts easy. It is easy to p3d print blind threaded holes to mount the encoder from the inside of the enclosure, then you screw the enclosure box with mounted encoder to the back of the motor. Finally to tighten the set scre to the motor shaft. (Leave a hole for a hex wrench. Then a pan head screw closes the access hole. In my case I have the motor mounted inside two parts that assemble like a clamshell. Parts go into the shells then you assemble the shells. > On Jun 26, 2023, at 12:28 AM, John Dammeyer <jo...@autoartisans.com> wrote: > > Unfortunately access to the assembly is required to center things and then > tighten screws. Nice as an enclosure might be it wouldn't solve the problem > > What I have done, since I don't have the press in type screws, is with a > countersunk 4-40 flat head I used my little DB200 lathe to remove some of the > countersink taper. I think gluing this into a 0.055" thick mounting plate > will prevent them from turning and also then fit the 4 mount locations along > with holding down the encoder. > > Photo shows the screws and screen capture the plate I drew up. I'll use 4x > 3mm screws to go into the 4 corners of the motor. The two 4-40 threaded > studs (in effect) will come up through the other two holes. If the corner > holes are large enough there should be enough play to be able to center the > disk in the encoder. > > The down side is I've totally forgotten how to use my tool height setter and > touch probe to run the G-Code I've now created for profiling the plate. > Should have written myself better directions. > > Sigh... > John > > > -----Original Message----- > From: Gregg Eshelman via Emc-users [mailto:emc-users@lists.sourceforge.net] > Sent: June 25, 2023 11:22 PM > To: Enhanced Machine Controller (EMC) > Cc: Gregg Eshelman > Subject: Re: [Emc-users] Drilling holes in the back of a stepper motor > > Make covers that fit over and hold the encoder. Snap the encoder into the > inside of the cover, and the corners of the cover have holes to put screws > into the existing holes in the motor end cap. This would have the benefit of > protecting the encoder and the end of the motor shaft. > > > On Sunday, June 25, 2023 at 03:33:26 AM MDT, John Dammeyer > <jo...@autoartisans.com> wrote: > > The problem is the rear shaft isn't that long.? > > I went through the process of considering an adaptor plate that fastened to > the 4 holes.? ? There may be a fancy way of making a thick plate with a > thinned area just for the encoder mount.? But it would have to have a stud > protruding away from the back and then a nut.? The plate can't be thick > enough to hold both the encoder and threads for screws and still have the > encoder disk mount to the back shaft. > > The alternative would be to press fit on a shaft extension and then use the > stepper motor to turn the extension to be symmetrical with the axis of the > motor shaft.? Then I could use a thicker mounting plate. > > Or, given that the motor drives a 25:1 planetary gear and I'm really only > interested in tracking motor revolutions and detecting stall conditions > (hence quadrature) I could likely get away with a custom disk and some > slotted sensors too.? Also more complicated to build.? > > Trying to keep it simple and the easiest is to have the encoder screw > directly to the back of the motor.? However with StepperOnline motor by the > time it's here in Cdn $ it's over $100.? So I can take the risk and drill > holes in the back.? Or get creative with other approaches. > John > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > <ModifiedScrews.jpg><ProfilingMountingPlate.jpg>_______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
