We’re looking to use the mounting holes on the back of the neo housing to drive a sprocket. Does anyone know what lateral forces(forces orthogonal to the axis of rotation) the housing is rated for? I wasn’t able to find this anywhere in the documentation.
Interesting design choice. The housing is not meant to operate under load, which is probably why you can’t find any load rating for it.
Is there a reason you can’t attach a gearbox to the pinion end and attach a sprocket to the gearbox output?
Here is a resource for to performance for various motors.
https://motors.vex.com/
Sounds like there could be an X Y problem here.
What is the reason you are attempting to mount a sprocket in this manner?
There is a reason that we don’t want to attach a gearbox. This is a design for a robotics competition where the weight limit is is very small and this would save some weight. Also, are you sure that the motor isn’t designed to operate like this? The rev site says “Rotor housing compatible with REV Motion Pattern - Mount metal Gears, Sprockets, and Pulleys”.
So is this not for the FRC season?
I’m trying to find a way to direct drive a sprocket from the neo. I need the lightest solution possible as this is for a robotics competition with a very small weight limit. The sprocket attached to the housing would be a very light solution but of course I don’t expect the housing to be able to take much force so that’s why I’m asking.
I will caution against running a chain 1:1 off of a neo 550, generally a belt would be used in this application as chain really isn’t designed to run this fast.
Furthermore, for this competition, are you using the neo 550 because it is the best motor for the job or because it is what you are familiar with.
Frc alum have a nasty habit of applying FRC COTS to engineering challenges when there is other comparable hardware out there that may be cheaper or better suited.
3 Likes
Noted, thanks, I understand. We were also considering a belt and my question of force remains the same for a pully or sprocket.
Yes, it looks like you can attach a sprocket to the neo 550 housing. But just because you can, doesn’t mean you should. The housing may be able to take side loads, but output pinion on a motor is designed to take such loads much better.
The biggest issue I see is torque. The neo 550 outputs 1 Nm (0.7 ft lb). That’s at the center of rotation. if you add a sprocket, you need to divide by the radius of the sprocket. So a 1" diameter sprocket or pulley will drop your torque to 0.35 ft lb. That may be enough, might not, depending on what exactly you are trying accomplish. Also as Skyehawk mentioned, since you have no gearing, the output will be running very fast, which can cause its own problems.
If you are concerned about weight, I am sure there are other ways to cut down. Is weight you only requirement? What about the needed torque, or the loads it must sustain?
If you really need this kind of speed, you can throw a gearbox on these without any intermediate stages and end up with ah hex output, which will be far easier to work with. That would also take side loads much better.
Haha yeah, definitely using it because it’s what I’m familiar with. But also because it seems like the right one for the job. Any advice/resources for determining if there’s a better motor?
There is the jvn calculator, I’m not really a fan of it though.
You could start with the torque / speed requirements, then head over to motors.vex.com and go though the motors. Take a loot at where you operating conditions line on each motor curve (torque, speed, power draw, etc).
Ex, for the neo 550
https://motors.vex.com/other-motors/neo550
We can see at free speed it draws 1.1 amps, and spins at 11000 rpm or so, with 0 output torque.
On the other end, we can see the motor can output about 1Nm of torque when stalled, but draws over 100 amps, and will not turn.
If all your after is near free-speed rpm for a light weight battle bot I would look at 300 or 500 class 12V motors distributed by Banebots or a 550. Simple lightweight speed controllers, brushed, cheap motors up to 15 volts input for the motor, industry standard shaft sizing.
Sure it doesn’t have the stall torque of a neo 550, but it sounds like your application doesn’t need low end torque. Sure the motors are heavier, but the speed controllers should be simple and light as long as you don’t expect the motors to stall.
This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.