well this is my first post here so hello
(if there are any spelling or grammar mistakes im sorry lol)
im looking for a way to design sheilds for the motors on the mk4 and mk4i swerve drives.
the shields need to connect to the chassis and need to protect the motors from any harm from impact with other objects/robots.
mk4:
the mk4 motor shields that i have in mind are just big aluminium L pieces that are about 50x50x2 mm. the problem with this desing is that its too strong and last year it was on my teams robot and our chassis got a huge disformation on its side.
mk4i:
i have no idead on how to design these motor sheilds. from what i know they need to cover up the bottom part of the Falcon 500 motors (that are positioned really close to the floor) and protect them from any objects that may be on the floor. i wanna say that it would be logical to make these shields more roundish to spread the impact evenly but i am really in the dark here.
it would be really awsome if ill get some help with this because im lost and dont really have anyone to ask about this because no one on my team really know how to tackle this topic.
if you have any idea on how to design one of these motor shields or any questions regarding the topic feel free to contact me via discord (doggercow) or start a discussion in the comments.
What manufacturing capabilities do you have? The recommendations are going to be different if you have a CNC router (or not), or if you have complex-and-precise sheet metal working capabilities (or not).
What are some examples of situations you’d like to protect the motors from?
In the first case – MK4 protectors – what were the chassis rails that bent made of? (material and dimensions) Many teams discovered that 2 x 1 x 1/16" wall aluminum tubing (or REV MAXtube) was not sufficiently strong for use as chassis rails.
I do have access to a cnc and i can use it if i want to. it was my plan to use it no matter what because i figured that the protectors would be with some heavy weight reduction and there is no other way to do so.
the chassis rails that bent where 20x40x2 mm but the new chassis that will be built along with these protectors will be 20x40x3 mm rectanguler. But that chassis also had some 10mm holes in its sides for bumper screws and the chassis bent mostly at that point.
Wow, yeah, 10mm holes through 20mm tubes are a bit much, and 2mm is fairly close to the 1/16" that people were having problems with.
Back to the original question: what are some situations you’d like to protect the motors from?
Are you just looking to contain grease and shield the gears from debris? Or are you trying to prevent the motors from getting damaged by robots, field element, game pieces, etc…?
im trying to prevent the motors from getting damaged by outside object like the ones you mentioned.
these are the shields we had last year. they were too hard and wouldn’t budge and because of that the energy transfer disformed our chassis. (the big purple L)
We haven’t had much of a need to protect our motors with MK4i’s the SDS midplate does a pretty good job of doing that, we found other parts will break before any impact force affects our motors. We have created covers to keep grease in and aluminum shavings out:
It’s an engineering problem; the energy from the collision has to go somewhere. In this case, the energy went into deforming your chassis. You could make the shields less strong, but then they might not protect the motors.
Regarding manufacturing, it looks like your 2023 guards are made of sheet metal?
Could you provide more information about how your chassis bent last year? It may not be that your motor guards were too strong, but that your chassis was not strong enough. Again, the difference between 2mm and 3mm wall thickness is substantial.
The tubing you described – 40mm x 20mm x 3mm – it’s smaller than the typical inch tubing available in the US (2" x 1" x 1/8") – that would be roughly 50mm x 25mm x 3mm. If you have the option to use slightly larger tubing, it might help.
last year our tubing was 20x40x2 and im desinging a chassis that is much stronger with some reinforcments on the inside.
the bent in the chassis was surrounding the bumper screw hole (that was way too big 10mm~) and the chassis that im desinging is using 20x40x3 tubing and is much stronger, so i can use last years shields as a last resort but i want to desing something more elastic for small impact and that would disform to not transef the energy from a big hit
i think something like what 5990 did this year would work fine with some adjustments.
thanks for the mk4i top covers, they are really useful
the problem here is that the midplate in my chassis will be way higher and wont provide a lot of coverage for the motors. its because we are shortening the corner spacers to fit our 20x40x3 mm tubing instead of the 1x2x1/8 inch.
beacause its now a lot shorter the motors are exposed and the gap between the chassis and the floor is 10~ mm higher, meaning that something as big as 10~ mm + the original gap can damage the motors without being moved by the chassis
You can add CNC’d alluminum spacers above your 40mm tube so the L bracket clamps down on 2in worth of material, 254 did something like this in 2022 to get closer ground clearance but you could use a similar idea
now you see the problem with this is that for some reason the guy that’s incharge of our lathe just took the spacer’s already and now they are 40 mm long. i think we have a box of spare parts but i dont know if there are spare spacers. ill check on sunday.
