Robotics Parts General

This is a place to talk about any parts commonly used for robots, that could be used by us.

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My example of their parts failing was a lot because of heavy use in not entirely optimized designs.

Stuff like gearboxes, and the versachassis can be a real pain if you are not experts in assembly and design around them. Pretty easy to mess up with them is my point.

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You are gonna love this, my friend is making a robot and I got him to use mostly skate parts :joy:


I for one want to see a CVT like the ones used in FRC. It doesn’t look like it should be too difficult to incorporate into a motor mount, but it’s going to need some custom machined parts, particularly the split motor pulley and a servo mount. Also idk how well V-belts do under high loads, but then again those robots aren’t light either.



They would probably need to be under a lot of tension to have decent torque transfer. And if thats true, then you can kiss your freeroll goodbye.

Other than that, I like the idea alot.

@Savage1 whad’ya say bud? Up for a challenge?

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CVT’s are not meant for long term use, you’d need the whole assembly in a gearbox to keep road dirt from ruining the grip between the motor side pulley and v belt, and those parts will just generally get hot and wear down fast. You can push a decent amount of power through them if you design it right though


I’m so glad I wasn’t the only one thinking about this. Its unfortunate CVTs are stupid inefficient.

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Agreed, but even a simplified version might still be cool. Instead of having it controlled via servo, just have multiple fixed positions that could be adjusted manually, so you could have manually adjustable fixed gear ratios depending on whether speed or torque is needed, without having to switch pulleys.

Honestly I would rather have a 2 or 4 speed fixed ratio transmission with clutch plates (I think a derailleur would end up larger), either hydraulic/fly by wire manual control or actuator automatic control

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Yeah that sounds a little too large and complex with two drives (especially with syncing), unless you’re going for a single motor with a diff to split torque to the two wheels which would be an interesting build too.

Probably the easiest is a 2 speed fixed ratio with a fuzzy momentary shift. The motor has a spline output with the mating axle having 2 conical features with a shared base, and the 2 motor gears have the inverse conical feature on the inside, so if you push the secondary axle towards the motor it engages one set of gears and if you pull it away you engage the other set of gears, and I personally think the best way to do it is to have it spring loaded to bias towards the high gear with a manual trigger for low gear (equivalent to starting in 1st gear or downshifting on a hard acceleration), so the remote has a secondary button (I like thumb wheels so the wheel is the motor power and the trigger is the shift, or if you use triggers the other way around) and the more you push/pull the more the servo pushes the secondary shaft and that changing time is probably enough for the motor to match speed since we use current control not duty cycle control

In terms of implementation it would look like a double wide gearbox (wheel, case cover, low gear, shifter, high gear, motor mount, motor) with an extra block on the opposite side of the motor, and to use it you would start with the shift all the way in, start ramping up, and ease off the shift so it kicks up a gear, and keep accelerating to full speed

Edit: actually a better way to make this would be to have the double cone on the motor axle with a
diaphragm and spring between the motor mount and motor face so all the extra bulk is guarded by the gearbox, and you can sit the servo between the motor and hanger (servo is belt driving a course thread stubby turnbuckle so as it rotates a half turn the motor gets displaced but not rotated, and the spring is a rotary spring that spins the turnbuckle back to the high gear position)

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You can order those pulleys from a company called Torque Trans. I still get their emails. I designed a swerve module that could of had those dropped in if we wanted to test them. Never tested that module much at all.

Yeah having a convenient to shift gearbox would be awesome. I think to start the relatively simple ball shifters used in FRC robots is what we should use.
For a true off road board jumping around with shifting gearboxes would suck so maybe a street board is where they would be useful. Top speed is really only ever needed there anyways.

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@Savage1 whad’ya say bud? Up for a challenge?

:thinking: maybe, but no time right now though


The NEO motor has a 2in/50mm bolt pattern vs 44mm for 6374

Shaft is also longer so you would need to cut down the first block, if you cut it a lot then the shaft as well. No keyway so press and glue.

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I finally got a NEO motor to mess with.

Seems to be like a flipsky 5045 but ~500KV

The outside shell takes heat from the stator well, reduced impacts at the cost of airflow to the stator. The Falcon 500 motor has holes to allow airflow in this outer can.