Chief Delphi

Chief Delphi (http://www.chiefdelphi.com/forums/index.php)
-   Robot Showcase (http://www.chiefdelphi.com/forums/forumdisplay.php?f=58)
-   -   Team 1671: Off-season belt drive prototype (http://www.chiefdelphi.com/forums/showthread.php?t=87623)

steelerborn 24-11-2010 23:21

Team 1671: Off-season belt drive prototype
 
rev 1

rev 2

rev 3

Here is the prototype that the 1671 CAD team has put together.
It is driven by two standard tough box transmissions (for now).
The dimensions are 26.1 inches wide X 36.75 inches long, and only 5.46 inches tall.

It uses timing belts instead of chain to power the wheels.(sprockets and belts from sdp-si)
The system was inspired by team 1625's internal belt drive, and the tensioning system was modified from team 114's, the cool thing about it is the ability to tension the belt system externally.

We would love to hear what you guys think about the design.

Thanks :)

spacepenguine 25-11-2010 00:54

Re: Team 1671: Off-season belt drive prototype
 
Looks like a great drive base! We used a timing belt drive on our Lunacy robot and it was rock solid. We're still running it as a development and demonstration base. Ours actually doesn't have a tensioning system though.

steelerborn 25-11-2010 01:01

Re: Team 1671: Off-season belt drive prototype
 
Thanks, the team has worked really hard.
Really, that is great to hear. Yeah a lot of our mentors have been bringing up belts for a couple years now, and we wanted to take a different direction in 2011. They also save a lot of weight if your sprockets are good.

Eugene Fang 25-11-2010 01:15

Re: Team 1671: Off-season belt drive prototype
 
I'm not going to comment on the use of timing belt, as our team hasn't had experience with it. I do, however, have a few general questions and comments.

What size axles are you using? They look like 3/8", but I'd highly suggest 1/2" for cantilevered wheels. Also, What is the point of the diamond shaped bearing blocks? It would be much better for manufacturing if they were simpler.

Other than that, looks pretty cool. Good luck!

steelerborn 25-11-2010 01:25

Re: Team 1671: Off-season belt drive prototype
 
Yeah, all of the axles are 1/2" with cantilevered wheels 3/8" would be really bad. :eek:

As far as the diamond shape it was mainly for looks, team 114 used a simpler square sliding block, we may need to change this when we begin manufacturing, but we will definitely look into that.

Thanks

AdamHeard 25-11-2010 02:40

Re: Team 1671: Off-season belt drive prototype
 
Quote:

Originally Posted by steelerborn (Post 981908)
Yeah, all of the axles are 1/2" with cantilevered wheels 3/8" would be really bad. :eek:

As far as the diamond shape it was mainly for looks, team 114 used a simpler square sliding block, we may need to change this when we begin manufacturing, but we will definitely look into that.

Thanks

If it has no function, it shouldn't be there.

I'm with eugene, make them square.

I'd also say lose the pocketing on the crossmember and switch them to 1/16" wall. I can see why with teh slots you can't run 1/16" on the siderails, but I'd recommended losing the pocketing there as well. There is a lot of work invested in such pocketing, and without much gain.

Heavily pocketed 1/8" is actually weaker than solid 1/16", and often a bit heavier.

steelerborn 25-11-2010 13:27

Re: Team 1671: Off-season belt drive prototype
 
Yeah they have been modified to be square now, it was a really simple fix.
This is our first time using aluminum tubing (and welding) usually we are a 100% sheet metal design. I will definitely fix the tubing.

Do you know of any good sites to purchase square and rectangular tubing with a 1/16 inch thickness. I just got the ones on the bot from Mcmaster, but for 1/16 inch tubing they only have 1inch X 1inch.

Thanks

Chris is me 25-11-2010 13:30

Re: Team 1671: Off-season belt drive prototype
 
Shaker's working on a pretty similar prototype (but even shorter!). Insert your favorite variant of "great minds think alike" here.

I too think the lightening is a bit of a stretch. Taking material out of the sides (especially the sides perpendicular to forces in a box tubing scenario) weakens it a LOT. Considering you can cut a bunch of weight with square bearing blocks I would do that.

If you can think of a way to tension the blocks without using sliding bearing blocks, you can use unpocketed 1/8" tube to support your bearings. A lot of teams ran cantilevered wheels off of Toughbox Nanos last year which are made of the same stuff. This could save you a little weight and a lot of strength considering how aggressive your pocketing is around the bearing blocks.

However, unpocketed 1/8" tube for a whole rail is pretty hefty, so you may want to use 1/16"... but 1/16" of material is not a lot to hold a bearing with!

AdamHeard 25-11-2010 13:34

Re: Team 1671: Off-season belt drive prototype
 
Quote:

Originally Posted by steelerborn (Post 981919)
Yeah they have been modified to be square now, it was a really simple fix.
This is our first time using aluminum tubing (and welding) usually we are a 100% sheet metal design. I will definitely fix the tubing.

Do you know of any good sites to purchase square and rectangular tubing with a 1/16 inch thickness. I just got the ones on the bot from Mcmaster, but for 1/16 inch tubing they only have 1inch X 1inch.

Thanks

Coast aluminum, is great in California. We buy their sharp corner 6061 (NOT 6063!) square and rectangular. We also get a lot of round tubing from them.

There are other great metal suppliers in CA, but we've always been happy with Coast. Maybe ask 1323 what they use, they're much closer to you as you know.

AdamHeard 25-11-2010 13:35

Re: Team 1671: Off-season belt drive prototype
 
Quote:

Originally Posted by Chris is me (Post 981921)
I too think the lightening is a bit of a stretch. Taking material out of the sides (especially the sides perpendicular to forces in a box tubing scenario) weakens it a LOT. Considering you can cut a bunch of weight with square bearing blocks I would do that.

If you can think of a way to tension the blocks without using sliding bearing blocks, you can use unpocketed 1/8" tube to support your bearings. A lot of teams ran cantilevered wheels off of Toughbox Nanos last year which are made of the same stuff. This could save you a little weight and a lot of strength considering how aggressive your pocketing is around the bearing blocks.

I don't understand that part. We use sliding blocks in 1/8", what would the issue be?

In fact, we use 1/8" purely because of the sliding blocks, and it's usually the only 1/8" on our robot!

steelerborn 25-11-2010 13:38

Re: Team 1671: Off-season belt drive prototype
 
Thats cool that you guys are doing something similar, I hope you post it up.

Yeah I see what you are saying about the thickness, 1/8 without pocketing would weigh a considerable amount. But I need to make sure I can find a supplier for the tubing we need (2inch X 1inch, and 2inch X 1inch) that has those dimensions in 1/16inch thickness.

Chris is me 25-11-2010 13:45

Re: Team 1671: Off-season belt drive prototype
 
Quote:

Originally Posted by AdamHeard (Post 981924)
I don't understand that part. We use sliding blocks in 1/8", what would the issue be?

In fact, we use 1/8" purely because of the sliding blocks, and it's usually the only 1/8" on our robot!

I'm saying if one wanted to opt out of using bearing blocks, bearings would be adequately supported with 1/8" tube; otherwise you could step down to 1/16" tube without many problems.

steelerborn 25-11-2010 13:46

Re: Team 1671: Off-season belt drive prototype
 
I am not familiar with welding parts. Is it okay to use 1/8inch on the outside rails, and 1/16inch in the support bars?

AdamHeard 25-11-2010 14:21

Re: Team 1671: Off-season belt drive prototype
 
Quote:

Originally Posted by steelerborn (Post 981927)
I am not familiar with welding parts. Is it okay to use 1/8inch on the outside rails, and 1/16inch in the support bars?

Yup! and 2x1 is easily available in 1/16". You said 2x1 twice, what was the second size you meant?

I'm a big fan of efficiency. If you have to use 1/8" for the siderails, yes you *could* pocket it, but often that time and resources is better spent elsewhere. We compensate for this by extremely aggressive in parts that are easy to add pocketing to (all the plates that we get waterjetted, where pocketing is trivial to add). Although we get our framerails CNCd because we get a lot made, we have them designed such that they could be made on a manual.

Don't get me wrong, it's a good start, just trying to help you out.

Just curious, why have the double opening frame? You may want to close one end, if the game switches back to 06-09 bumper rules, you'll need some support there anyway. you may want to design in 6" segments on the intake side for that reason as well, and a bumper support system for the siderails. Never hurts to figure this stuff out a head of time so that it is well integrated into your design.

Cory 25-11-2010 14:28

Re: Team 1671: Off-season belt drive prototype
 
Quote:

Originally Posted by Chris is me (Post 981921)
Considering you can cut a bunch of weight with square bearing blocks I would do that.

How could you cut weight by adding more material? I don't think I'm quite understanding what you're saying.


All times are GMT -5. The time now is 23:45.

Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi