What kind of motors and gearboxes would people recommend for jobs like intake wheels. We have many smaller motors like the window and fisher price motors and full size cims but nothing in between. What kind of motors and gearboxes would be a good buy for most medium power operations like intake wheels. Thanks for any assistance that you provide.
VersaPlanetary + BAG or MiniCIM gives a lot of flexibility in speed/ torque and mounting.
For most teams I’d recommend using the versaplanetaries. Reasoning:
- Able to quickly swap ratios from 3:1 to whatever. (Use load rating guide for your application )
- Available with multiple output shafts.
- Direct drive wheels
- Easy to integrate with pulleys and sprockets.
- Most flexible option imo out of any cots gearbox available.
- This is what citrus does
Any 550 or 775 motor and versa planetary will work fairly well, however we’ve been switching over to bag motors for intakes because of their increased thermal mass that helps increase the margin for error when stalled.
I would consider a minicim overkill for an intake, especially considering the weight of the motor.
With the Banebot motors now illegal, I would recommend the AM 9015 or the VP BAG motors as the motors of choice for an intake.
Planetary gearboxes are great for this application, either the VP Versaplanetary or the Banebots P60. I’ve used both with great success.
If you do have the ability to make a custom gearbox, you do have the opportunity to save a bit of weight and efficiency with a small 3:1 or 4:1 spur reduction. Planetaries are great for getting a big reduction in a small space, but intakes are generally a high speed application. A great way to do this is to use 32DP pinion gears available from AM or WCP directly on the motor and using some of the aluminum gears that are targeted towards FTC: https://www.servocity.com/html/32_pitch_aluminum_hub_gears__1.html#.VmegwbgrJD8, and bolting them directly to the wheel.
That’s how we roll.
Versa Planetary and a hex broach, far you will roll.
One of the mistakes teams commonly make is under powering intakes. If you’ve got an intake or conveyor belt, you want to put as much power on it as you can get away with.
Yes, the Mini CIM might be overkill – but can you put a “price” on having a “Touch-It, Own-It” intake?
When I designed my first ever intake+conveyor mechanism in 2009, I asked one of my wiser friends for advice. He just told me: “The only trick as far as I can tell, is to throw power at it.” I’ve never looked back…
I also agree that using a modular planetary gearbox is a good idea for this application. I can’t count the number of times I’ve screwed up a gear ratio (“wow… this seems really slow!” or “hmmm… is it supposed to stall this easily?”) and been saved by adjusting the planetary used in the design. This versatility will allow you to swap in different ratios (or motors) to tweak your design.
Your Mileage May Vary,
Another reason for over powering mechanisms is that the smaller motors (BAG,9015) will require more reduction than the larger motors(CIM,Mini-CIM) due to a higher free speed. This year instead of using a small motor with a VP on our intakes we could get the same output speed at the same weight by using a Mini-CIM with a single reduction. Giving us more power with less cost, weight and complexity.
Anyone have any pictures of Mini-CIM intakes?
254 in 2013. though they started changing motors around. i forgot what they settled on for champs.
They aren’t great photos but:
Here is our intake without wheels.
And a side view with wheels
1114’s intakes also use CIMs
I can’t agree more; that approach definitely paid off for us in 2010. Our pincher intake that year was powered by a full-size CIM with a heavily torqued friction clutch (to avoid completely stalling the motor). There was sufficient current draw that we used current measurement to determine whether or not we had the ball–it consumed over 30A when it had the ball! It was hard on our batteries, but it was worth it; there were several times we simply yanked the ball out of other robot’s intakes, even on Einstein (definitely “touch-it, own-it”!).
Please note that fisher price motors have been illegal for a few years now… I would of recommend removing them from the shop so they don’t accidentally end up on your robot!
Another tip for intake wheels when it comes to selecting the right gear ratio and motors: Your “intake velocity” aka the linear speed of your intake wheels should be greater than the max speed of your drivetrain. This makes it easier for you to intake a game piece while driving at it full speed.
The MiniCIM/CIM for Versaplanetary seems like a great way to go to get more power - except for a major factor (IMO). How do we accurately and cleanly cut the CIM/MiniCIM output shaft down to 3/8"? We once made a prototype with a MiniCIM/Versaplanetary, but wound up using standoffs from the adapter because the kids weren’t able to figure it out at the time.
Our 2014 robot had a mini-cim intake (it’s hiding under the duct tape).
Not exactly useful for every team because it requires a lathe but… we had an interesting solution.
We clamped down our CIM motor inside the lathe and then, instead of turning the lathe itself, we powered the motor directly from a battery. Lathes are not designed to be used on a shaft that’s spinning quite that fast so it generated a lot of heat (make sure to oil it up). In the end it worked perfectly with the small caveat that the CIM shaft had burn marks on it.
We wrap the CIM/MiniCIM in pool noodles then clamp it in our table vise. We use visegrips on the end of the shaft that is going to be cut off, then just hack saw through the shaft. We sand down the end to clean up any sharp edges after we are done.
We clamped the motor in a vise. Held the shaft with vice grips and cut off the shaft with a dremel. Cut as straight as possible. My student took his time but really just eyeballed it. He then jsut filed the edges to remove any burrs. Didn’t have any issues with it last year.
You can run the versa planetary without modifying the CIM output shaft. I talked with Aren at vexpro, and the original intent for the CIM adapter was to leave the shaft unmodified. I do not remember the reason for them suggesting the modified shaft for normal usage, but we ran mostly unmodified CIM shafts with the adapters as shown below.
You have to leave all the stages in the gearbox for shaft clearance. We did have to shave off the end of the output shaft around .010"-.020" with a file to remove a minor interference.
We had zero issues with the setup for the 2015 season.