Quote:
Originally Posted by Joe G.
- Any particular reason the ball shifters are up so high?
- The hole pattern on the flanges looks irregular and uneven in parts. One of the greatest things about sheet metal is the ability to standardize things like this, so you can mount parts readily. My team does a 1/2" spaced 5/32" hole pattern, which allows parts stamped with it to be used for #8 through holes, #10 tap holes, or 5/32" rivets, without any additional drilling.
- What thickness is used?
|
I left the ball shifters high so the inner and outer channels could be non-unique to try and cut down on manufacturing time.
...but I didn't think about the higher CoG, that's a great point. I'd rather increase manufacturing time (which isn't much anyways) than sacrifice performance.
The hole pattern is actually consistent, for some reason the render removed random holes. On the front/back channel has .192" holes spaced out 1" for 3/16 rivets. While the side channel alternates between .192" and .257" spaced out 1". That way we have the option of 3/16 rivets, 10-32 or 1/4-20 bolts.
And the entire chassis is made of .100" aluminum. The reason being that our machining sponsor has that readily available. And our drivers have always played aggressive defense when needed so I don't mind using thicker metal
Quote:
Originally Posted by DampRobot
Also, are you doing exact c-c with the wheel chains?
|
Yes the chain is all center-center distance, and I planned to use idler sprockets as tensioners to make up for stretching. But the idea to use the cross bracing as tesioners would be much more efficient. I'll re-design and add cross-bracing tensioners.
Quote:
Originally Posted by nathan_hui
Are your center wheels dropped?
Is there a particular reason for the non-direct drive design choice? You now have a single point of failure in the chain going from the gearbox to your first wheel. Remember that when you use master links, you need to design for a FOS of at least 6.
Does the chassis need to that thick? Having the wheels in a well is good for aesthetics, but when it comes time to maintain the drivetrain, that's just a hassle. As you make the chassis thinner, you reduce the amount of chain you need (thus removing a lot of steel from the drivetrain). You also reduce CG, and increase the amount of vertical volume for the rest of the robot.
|
Yes the center wheel is dropped .100"
I chose not to direct-drive one of the wheels because my target top speed was between 16fps and 14fps and directing driving the wheels would have a calculated adjusted speed of 20.5fps! Way to fast for our driver to handle!
Could you explain more about the thickness of the chassis? I'm not quite sure what you mean. and I'm unfamiliar with the term FOS, what does that mean?
Thanks everyone for your help so far!!