TB Nano Encoder Spacing

[daltore]

We got two Toughbox Nano's this year for our mechanum drive, and tonight we started mounting encoders. But there seems to be a problem - the entire drive shaft wiggles axially by about 1mm on one and 1.5mm on the other. Since the encoder disks mount directly to this shaft, we're worried that this may cause the disk to get out of focus, or even possibly crash. Has anybody else noticed this issue, and what's your opinion of the wiggle room on the encoders?

[Alan Anderson]

The E4P encoders are remarkably tolerant of slop in the shaft. I'd still look closely to see if there's a place you ought to install a spacer in the gearbox.

(It sounds like you might be trying to do mecanum drive with only two gearboxes. I hope I'm reading that wrong.)

[daltore]

I'm not sure it's going to be that easy to install a spacer. We definitely could, it should just be a large washer, but we'd have to take the E-clip off, and then the whole gearbox would fall apart. But it's good to know US Digital knows what they're doing. I am still worried about the whole millimeter and a half, though, but I guess we'll just have to give it a go and see how it turns out.

[Dad1279]

We put an extra washer in the output shaft and removed the endplay. I believe the students put it on the 'encoder' side of the shaft.

We used a screwdriver, modified by bending the tip 90 degrees, to pull out the c-clip and the output shaft pulls right out.

[daltore]

Thanks, we'll try that if we encounter any problems. They've already got the encoders mounted, so for right now we'll just see how it goes. I'll keep you posted.

[Dale]

We also installed a nylon washer on that shaft. It's hard to imagine the encoders would work well with that kind of play in the axle. Even if they did, you'd have to be careful when installing the encoder to do it in such a way that the disk wouldn't run into the housing/sensor when the axle is at one end or another of it's travel.