Hello! I was hoping for help with a pair of 12v motors with a PG45 gearbox and any assistance is appreciated.
I’ve got a pair of somewhat sizeable motors (They’re discontinued from Lynxmotion but similar specifications here: http://lynxmotion.com/images/jpg/rb-wtc-01-dimensions.jpg )
I’m trying to find the best motor mount and beyond that, some kind of cradle or additional support.
The application is a relatively simple robot with 2 drive wheels and a swiveling support wheel
My concern is that if I use a bracket like this (Not the correct size it’s just for illustration) that the motor/gearbox assembly will be putting a lot of strain on it just by sitting around. If there’s a way to further support the assembly farther from the axle side that would be ideal. I’ve used smaller versions of a round mounting bracket with a tightening screw but those were for motors ~15mm in diameter
I’ve tried a couple large stepper motor brackets but the screws weren’t quite lined up and there’s the raised circle around the shaft on the gearbox doesn’t match the one on say, a NEMA 17
Googling PG45 brackets brings up a lot of cad drawings or 3d printing models and I don’t currently have the equipment to fabricate my own here. That, or it returns Amazon results for brackets for smaller motors.
Is there a good bracket for this PG45 gearbox with a motor?
Is there a method of additional support for a motor with a diameter of 45 mm?
Again, thank you for any help
@brendanh Welcome to the RobotShop Community. The 90 degree mounting bracket is as the name intends - to mount the gear motor at 90 degrees, when otherwise it would need to be mounted to the face of the gearbox. In terms of the strain, the only real way of knowing is to do a finite element analysis of the setup based on material properties, actual loads etc. If the load on the shaft is away from the bracket, then yes, it will flex, but what exactly the flex will be based on the load again required FEA.
In terms of dimensioning, it’s close with four equally spaced holes on a 38mm diameter circle, whereas the motor you linked to has four equally spaced holes on a 37.5mm diameter circle. The drawing for the gear motor doesn’t show the diameter of the “lip” where the bearing is installed, and the drawing of the bracket doesn’t show the diameter of the opening. It looks large enough though, but cannot verify.
The only other method I’m aware of would be a pair of 45mm diameter clamping mounts, though the largest I’m aware of is 37mm as opposed to 45mm.
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Thanks for the information, and thanks for the welcome!
For strain on things, I think you’re right in that I’ll just need to try it with the actual components to see if it’s acceptable. Otherwise I’ll need to drop around $6000 on simulation software!
It looks like these clamping mounts are a hair too small for these big PG45’s / the motor they’re attached to, as you thought. However the name “clamping mount” is useful (just getting the name of the thing can be so tricky, since I’m a terrible novice)
As for the metal bracket to attach to the front of the motors looks like I’m going to need to keep looking for something built for 45mm. the 37mm is close, but, I’ve already got several “pretty close but no cigar” mounts here. (Maybe I could finally justify a drill press and just modify these!)
Again thanks for the info!
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Don’t know how much load you plan to put on the motors, but keep in mind that the shaft protruding from the gearbox is likely only supported at the end by one ball bearing, which means it’s not great when it comes to radial loads.
In terms of mounting if you take inspiration from the Actobotics clamping mount, design a beefed-up variation to 3D print in plastic it might work well. Metal’s always best, but not everyone has access to inexpensive machining / prototyping.
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Yeah given the heft of these motors a metal bracket seems best, plus the clamping mount farther back. Since I lack a 3d printer or lathe I ended up “cheating” and getting a 57mm bracket and will use a friend’s drill press to modify it properly. Perhaps that’s excessive but I was getting frustrated. I have no idea why the 45mm brackets exist only as 3d printable models!
Thanks for the heads up on the radial load issue!
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