pic: Nah, We just have a set for the Alpha bot and the beta Bot

Our first year with a real machine shop sponsor. We’re finally able to play a bit with designs. What a bear it was to assemble with keys and shafts in bearings. With the welded sides we had to be quite creative to key the bevel gears and one hub per wheel and still put a bearing on the other side of the wheel and the outside of the module itself. Next time we’ll not weld the sides, we’ll bold them on.

Might be a dumb question, but are you using 2 wheels per module? By the looks of the housing, the width seems to be quite large. :confused:

It’s actually another method of crab to do that. You can run the drive shaft straight down to the miter gears, which removes the need for either chain or spur gears to drive the wheels. It makes for a less complex swerve module, but at the expense of a hefty amount of (horizontal) space.

I’m guessing that’s what they’ve got going here.

Not to mention the fact that there are twice as many wheels as modules.

It might be a combination of the simpler swerve module idea and two wheels per module. The bevel gears could be between the two wheels in the module.

Spares buddy. :wink:

But Craig, wouldn’t it be kinda sorta pointless to have more than 1 wheel per module? Don’t you actually lose traction since its greater weight distribution? And of course, this is all assuming that they actually are using 2 wheels.

My Guess Based on the title of the pic: “Nah, We just have a set for the Alpha bot and the beta Bot”
2 Robots
Spare set of wheels for each bot or 2 wheeled modules for each bot

Should be fun either way :slight_smile:

I think theres two wheels per module with the drive shaft going down between the two. The second wheel on each module could be to spread the weight out so that the wheels wear slower…

thefro526, you hit it on the head. We have two bots and two wheels on each module. We went with the two wheels only because the drive shaft leading down to the bevel gear comes down on the side of the wheel and creates unnecessary stress on the horizontal shaft. By sandwiching the bevel gear we equalize the downward force.
As for the traction, it’s simple physics. We neither gain nor lose traction. We especially like that they swap out easily and will bring the 4 beta bot spares to the competitions–hopefully unnecessarily.

So awesome. I love when I’m right.

Thats an awesome way to build a crab though. I really like the amount of forethought that you’ve put into this. I wish you all the best! Whats the projected weight on the whole thing? It seems like it may get heavy pretty fast with the extra wheels though.

Can you guys post a picture of a completed module when you have one done?

Are you using custom hubs or AM ones on the wheels?

To answer three of the above questions;

  1. Yes, I’ll post pics of the hubs completed and installed, I left the camera in the shop or I would have done it this evening.
  2. The weight is heavy–about 4.7 lbs for the complete module. We were going to put some “speed” holes in it but just haven’t gotten around to it yet. We will, however, if we’re close on weight overall. We just installed them on the bot this week and used .078 thick thrust bearings in a delrin sandwich. OHHHH baby!
  3. Yes, they are AM hubs, half are milled down to fit (We don’t want to take advantage of our sponsors by having them make that which we can get elsewhere).