"West Coast" drive?

[MrForbes]

Great! lets get going on them...

[GUI]

My plan (once i get a model done, I'll post in on the open source chassis thread) is basically this in 6wd form with a supershifter directly driving the center wheel. All that would be needed to make it would be a saw, a drill, and tin snips (though the sheet metal shear makes that part much easier).

[sdcantrell56]

Mine is very similar to that although with shorter frame rails and all the bearings are mounted in laser cut 1/4" thick aluminum brackets since I'm worried about the bearing holes enlarging in the wood.

[MrForbes]

I think with a hardwood, the bearing holes might be ok. This is something that would need to be tested, of course! also thin plywood might be better for the "belly pan", as it's easier to buy locally, and to cut to size, and to attach firmly (glued and screwed).

oops! we sure hijacked this thread

[roboticWanderor]

Team 418's "Wood Coast" drive train was a basic west coast style created using nothing more than common woodworking tools. It is achievable to make these designs using nothing more than a saw and drill press. going down from sliding bearing blocks, multi-speed transmissions, and direct axle drive can really simplify a design, and rid your team of the need for a mill, or other machine work. I hate to say this, but the "west coast" drive trains used by team's such as 254 are overly complex, and require a lot of machining compared to equivalent designs. Many teams (who win a lot too) go without expensive options such as direct drive gearboxes, such as 1114, or 330.


PS: sorry for ragging on your robots guys, i just wanted to make the point that these types of designs are possible without the use of expensive machines or parts.

[sdcantrell56]

I know this isn't exactly rookie friendly but I am throwing around the idea of making a west coast style drivetrain from laser cut pieces of 1/2" thick meranti or baltic birch plywood. For all cross members and side rails, I would epoxy 2 pieces together to form a 1" thick piece, and then the base plate would just be the 1/2" thick material. The base plate would provide a huge amount of stiffness with a relatively low amount of weight since its wood. Also if it's not strong enough we could always lay up one layer of fiberglass. I would think that epoxying 2 pieces of plywood together with a few screws would be super strong. I will try to post up a cad rendition I have in a little bit.

[AdamHeard]

Originally Posted by roboticWanderor

Team 418's "Wood Coast" drive train was a basic west coast style created using nothing more than common woodworking tools. It is achievable to make these designs using nothing more than a saw and drill press. going down from sliding bearing blocks, multi-speed transmissions, and direct axle drive can really simplify a design, and rid your team of the need for a mill, or other machine work. I hate to say this, but the "west coast" drive trains used by team's such as 254 are overly complex, and require a lot of machining compared to equivalent designs. Many teams (who win a lot too) go without expensive options such as direct drive gearboxes, such as 1114, or 330.


PS: sorry for ragging on your robots guys, i just wanted to make the point that these types of designs are possible without the use of expensive machines or parts.

254/968's iteration is the simplest West Coast Drives I've ever seen. They took some liberties and cut a lot of weight by increasing the machining complexity, but they have the resources to do it. A CNC doesn't care if it's cutting a curve or a straight line. They could very easily scale back the design to be "easier" to make and it would still be the simplest West Coast Drive.

Also, separate issue; a West Coast Drive is center wheel direct driven, cantilevered wheels in 2x1 extrusion, #25 chain from gearbox to outer wheels on the inside of the frame. Any similar bases are just similar, not West Coast Drives.

[MrForbes]

You need to get one of those little circles with an R in it after the phrase West Coast Drive

[ajlapp]

All the files for the Universal Chassis are open source and downloadable from my website. www.team221.com

We took the major concepts from 254/968 and team 60 and made them production friendly. All components are made from stock sizes, they have no complex machining and every part is bolt together.

I made the first production batches in my home shop with a standard Bridgeport. A band saw, belt sander, scroll saw and drill press would suffice.

[waialua359]

Cory,
Its time for a post with a history lesson on teams 60, 254 and 968. We definitely remember Glenn and his contributions to many teams today with that drivetrain.
What's more impressive is that all of you from teams 100, 115, etc. are now the new engineering "crew" continuing the traditional West Coast dominance.

[Andy Baker]

Originally Posted by waialua359

Cory,
Its time for a post with a history lesson on teams 60, 254 and 968. We definitely remember Glenn and his contributions to many teams today with that drivetrain.

Yes, I agree. The history behind this would be great. I think that it is was a development between design leaders Glenn Thoroughmann (60) and Steve Kyramarios (254), with their teams' help, but I am not sure.

Andy B.

[Travis Covington]

Team 60/Glenn had the directly driven cantilevered wheel way back in 2000 (in 99 they actually ran belts!). The cantilevered/directly driven idea is what I have always felt was the heart of the system, and what made it unique, elegant and ahead of its time.

The 6wd iteration used in 2004 was just the expected evolution of an already proven and well developed concept.


And as far as complexity is concerned, you are correct to a point. There can be much simpler ways of doing this same concept, but the way it is done now eliminates a lot of parts, increases reliability, eases in maintainability and has far fewer frictional losses than doing it pretty much any other way. Since we do have the resources to manufacture these parts, these other benefits I just mentioned create an advantage (in our eyes) over alternative methods and "simpler" designs.

[pogenwurst]

Oh dear, look at what I've gotten myself into now -- I should stay in programming where I belong.

In all seriousness though, thanks a bunch guys, this clears things up quite a bit.

Just to verify my understanding: the term "cantilevered" has come up quite a few times in reference to wheels; that just means that the shaft that the wheel is on isn't supported on the end, right?

My apologies for replying so late; I was out sick from school for almost a whole week and subsequently quite swamped.

[EricH]

Originally Posted by pogenwurst

Just to verify my understanding: the term "cantilevered" has come up quite a few times in reference to wheels; that just means that the shaft that the wheel is on isn't supported on the end, right?

Correct; it can be used for almost anything where only one end is supported and the other end has a load on it. In this specific instance, the wheel is on the cantilevered end.

[pogenwurst]

Originally Posted by EricH

Correct; it can be used for almost anything where only one end is supported and the other end has a load on it. In this specific instance, the wheel is on the cantilevered end.

Thanks. Is the only advantage of such a setup easy maintenance / wheel swapping, or are there others?