Hi all, I was trying to through and eliminate as many potential sources of friction as possible when using motors with the blue (600rpm) cartridges on a drivetrain prototype. One thing I noticed was that the smallest amount of flexing of the structure could create a significant increase in load on the motor (e.g. going from 5% to 15%+ torque when unloaded). Long story short, one of the issues seems to be the metal insert (pictured).
These are almost a perfect fit inside the plastic housing and what seems to be happening is when drive shaft is not completely perpendicular to the motor, for whatever reason, you can get rubbing of the insert against the housing.
For a low torque / high rpm application like this it seems the insert is really not providing any real benefit?
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yeah uhm dont put those metal inserts into the motor carts. you dont need them almost no one uses them on motors. the motors already have a recesse for ls shaft and it is plenty sufficent.
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Another option if you are trying to get better engagement between a motor and a low-strength (1/8" shaft) is to use one of the ‘High Strength Shaft Adapter’ pieces (https://www.vexrobotics.com/hs-hardware.html
These are the same adapters that come with the 12-tooth high-strength pinion gears.
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Oh lol, i never thought about putting one of those in the motor directly. Makes perfect sense, thanks.
Also, don’t forget that you can simply file the edges of the insert to make it smaller.
It is perfectly legal to modify most of the non-electrical parts, according to R16.
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Yeah, that’s an option for sure. I’m trying to figure out how to get our middle school teams to do a minimum amount of part mods as possible (even cutting c-channels). We had been using individual 2 or 4 motor drivetrains up until now, but trying to get geared drivetrains to support 6 wheel configurations has been challenging from the precision needed. Anyway, working on a more lengthy post about all these options - not quite ready yet.
Thanks
Nick
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