Quote:
Originally Posted by Dr.Gusta
Was gone for most of the day today after posting this last night and was very shocked to see how popular this was. I am first going to 3D printing, all of that discussion was all for not because my team does not even have access to 3D printing and would be cheaper to mill one in house then to pay to have one printed. Now to asid61's questions
1. I currently do not know how to calculate weight in Inventor but I am sure after a quick google search I will figure it out and get back to you on that one. The plates are 0.25" alum if that helps.
2. We mount our electronics on the belly pan of our robot and constantly ran into issues because the motors were in the way. Also I started this team last year and a vast majority of the team is graduating this year including me. We are working to get a permanent workspace, machinery, etc. so we can establish a program that continues after the founding members leave. We want to create a robot this year that will set a standard for members that follow us that we strive for creativity (bevel drive) and quality custom. I know this can be done in an off season project, too much risk, etc but in the end it is our team and this is what the team wanted to do and that is what it comes down too. I know there are many reasons not to do it but think of what we will learn doing this! In the end it is not about a robot but what has been learned during the process of building the robot.
TL  R Nicer form factor and it is what the team wants to do
3. It does not, that is a BEAUTIFUL gearbox but it is not ours and this is the design fits much nicer in a drive base and works for us.
As for our issues with gear ratios what really stopped us from gearing it further down was I thought that 9fps was way to slow already but after being told that is pretty fast and we will have breaker trip issues I will play with the ratios more. I will shoot for 16fps High and 5fps Low. Also here is a link to a better picture of the bevel gear setup should answer some of your questions. The bevel on the CIM is bored and keyed for the CIM then just slides on but a retaining ring will be added but no thrust bearing. The other bevel has a bearing on its 0.75" hub but also has a 3/8" hex shaft that goes through its bore to the rest of the gears. Both don't have thrust bearings. Hope that all makes sense
http://i.imgur.com/Vbxs3Sb.jpg
There was a lot of questions and comments and I tried to cover them all but what I really want to hit on again is that this is what the team decided as best and we will be making one during the off season using in house CNC equipment. Please let me know if you have any more questions or comments.
EDIT:
The bevel gears are also lined up exactly to the manufacturer's specifications so they should mesh perfectly and are made of steel. |
Ah, that explains a lot. Thank you. You could move to 3/16" plate, but for bevel gears I'm not sure you can get a good fit on the side plates.
THAT BEVEL GEAR MOUNTING IS AMAZING!!! Tons of potential here. If you change the ratio of the bevel gears to 1:3 or 1:4 rather than 1:1, then you can eliminate the final stage of gearing. Then, because of the size of a 4:1 bevel gear, you can put the first set of shifting gears right next to the face of the big bevel gear and only require two plates. That would slim down the gearbox a ton and make the weight much lower. The width would increase though, but not by much. The output shaft could be a vex shifter shaft then too.
EDIT: sorry for being pushy, but I'm used to trying to optimize gearboxes. Many times when I see a team's bevel gear setup, they use 1:1 in favor of 1:3 or 1:4. Generally this is because the Vex bevel gears are 1:1, but in this case I don't see why not go for a larger ratio, as it would optimize many things.