Thanks for the feedback!
A. The gearbox with motors and all except for the wheel is 7.21 lbs. I am not a fan of the 8t pinions as they are not true 20DP tooth profile, 12t is the smallest gear with the true profile. The 3rd stage is what allows us to change wheel size easily. For 4" wheels the ratio is 1:1, for 6" wheels the ratio is 1.5:1, and for 8" wheels the ratio is 2:1. The first large cluster gear is the size it is to be able to space the motors out far enough so that they don’t hit each other. Then we are somewhat limited on shifting stages. There was a lot of consideration behind what gears to use for each stage to try and hit our 3 target speeds. We are able to swap out our shifting stages to achieve top speeds of 6.5, 12, and 17 ft/s. This allows us to decide for each game what options we want and be able to change our minds mid way through the season and only have to swap out two gears. So we order a full set of gears to work for any game and we don’t have to worry about gears being in stock or shipping delays (this burned us really bad a couple years ago).
B. The style of our team is to have a strong drive so that we can play defense well and move other robots on the field, similar to 217 this year. We select the highest COF wheels we can every year (within reason) this usually ends up being AM plaction wheels with blue tread. We have been using 3 mini cims for the last few years, and have been very happy. We had the debate about 2 vs 3 when they came out, but the design was originally started with NEOs and then slightly modified for the Falcon so we left the option for 3 based on the fact that they are still way lighter than what we had been using in the past.
C. Our team doesn’t meet on weekends and are somewhat limited in our capacity as a team, so having one less thing to really worry about every year will be a huge help for us. We use 4, 6, or 8 inch plaction wheels with tread depending on desired ground clearance or 8" Pneumatic wheels if the game requires. We also determined that we will only want a combination of a pushing gear, a 12ft/s gear for mostly half field games, and 17 ft/s for full field games. This also allows us to have parts stocked for our gearbox before we have made any decisions and just have to make a new set of mounting plates and spacers and we are off and running very quickly.
D. Our intent was to build the chassis and gearbox during the off season and then make a final design with a little bit of light weighting, but we didn’t get a chance to build them. Also, all three of the plates combined are only 1.64lb so we won’t be able to save much weight.
E. The belly pan is currently 5.47lb, we could go a little thinner with our spacing between the diamonds, but this design was mostly about the gearbox. We are also going to be adding mounting features for our electronics on the bellypan, so it is also not final. Also, going back to our play style, the more rigid our base is the better.
Overall, the design does not meet the needs of every team, but based on our goals for the gearbox design and the needs of our team this design is what we need.
-It gives us flexibility for wheel size
-flexibility for robot speed
-gives us shifting in a more compact package than anything I could find from Vex or WCP
-it is relatively easy to assembly and service with all of the bolts being accessible and going the same direction