GearBox built in Chassis frame

[tomer]

We thought about creating our gerbox frame into our chassis frame. Any experience? What do you guys think?

We are currently leaning towards shifters, possibly with PTO.

[Joe Johnson]

Originally Posted by tomer

We thought about creating our gerbox frame into our chassis frame. Any experience? What do you guys think?

We are currently leaning towards shifters, possibly with PTO.

This can be a disaster or it can be your ticket to Einstein. It depends.

In general, you need a reason to do this beyond just that it can be done. For most teams, building custom gearboxes at all is probably the wrong answer. There are so many awesome COTS gearboxes and transmission there really isn't the need. You can build a great competitive robot without it.

So why?
Well, sometimes you just want to roll your own gearbox because gearboxes are cool and it is inspiring to get into the mud with involutes, addendums, dedendums, pressure angles, center distances, ...

Other times, you have a really great concept that just can't be done without the special something that a custom gearbox brings to the party.

But whatever the reason, it is going to be harder and, unless you know what you are doing, probably not as robust as buying a COTS gearbox. Oh, and if you need a spare (and you should probably plan on it) then you need to build it yourself. And if it is built into the chassis, it probably isn't as simple as loosening a few screw and swapping the thing out.

I design gears and gear boxes for a living. I am HAPPY to write a check and have a solution in mailed to me.

YMMV.

Dr. Joe J.

[Roboshant]

Going of off what Dr. Joe said it would definitely be much wiser to stick with a COTS gearbox, especially if you have not made one before. You can easily get a WCP dog shifter gearbox on vex pro and buy the PTO add on kit.

[Lireal]

Originally Posted by Roboshant

Going of off what Dr. Joe said it would definitely be much wiser to stick with a COTS gearbox, especially if you have not made one before. You can easily get a WCP dog shifter gearbox on vex pro and buy the PTO add on kit.

Can that attachment be used with the 2 CIM WCP shifter? On the page you linked it says it is intended for the 3 CIM version.

[R.C.]

Originally Posted by Lireal

Can that attachment be used with the 2 CIM WCP shifter? On the page you linked it says it is intended for the 3 CIM version.

We (WCP) are releasing a robot reveil Monday that shows integration of a WestCoast drive, pto, intake and hanger.

But to answer your question you can use it with 2 CIM or 3 CIM.

[Chak]

Originally Posted by Lireal

Can that attachment be used with the 2 CIM WCP shifter? On the page you linked it says it is intended for the 3 CIM version.

Take out a motor and it will become a 2 CIM shifting gearbox with PTO.

[philso]

Looking through this forum, you will find many gearbox designs that people have posted over the years. These have had different features and have been the result of many different design decisions. Many of them go through multiple iterations as design flaws are found or the demands on the gearbox change. The one thing that they have in common is that they are all stand-alone gearboxes that can be fully assembled outside the chassis and are attached to a chassis as a sub-assembly. It is not too difficult to swap out a gearbox sub-assembly if the design is found to be inadequate. It would be much more difficult to change the gearbox design if it is an integral part of the chassis.

It is probably only worth considering a gearbox that is integral to the chassis in instances where the manufacturing volume is very high, the target cost must be very low and there is adequate time to build and test multiple iterations of the design. Dr. Joe might be able to confirm this.

[Tom Ore]

We put the gears inside our frame last year - you can see info about it in the "Behind the Design" book. Page 69 shows the assembly drawing of the frame.

[Joe Johnson]

Originally Posted by Tom Ore

We put the gears inside our frame last year - you can see info about it in the "Behind the Design" book. Page 69 shows the assembly drawing of the frame.

I know of a lot of teams that do this. For example, I think HOT (#67) has done this to great success in the past.

It is not a terrible idea. It is not a great idea. It's what I call an idea for consenting adults. Don't do this unless you're ready as a team.

Cheers,
Dr. Joe J.

[tomer]

Thanks a lot for the detailed responses!

It is probably not wise for us to go custom this year..

Any recomandation on good shifter + PTO gearboxes?

I have looked over the WCP 3 cim gearbox before, but its quite pricey, is it worth it? Are there any good alternatives?

[TikiTech]

I personally love our West Coast Products 3cim dog shifting transmission.
Was a wonderful addition to our drivetrain and was the sole reason our robot was such a great defensive threat during Arial Assist. We were the assaulting robot for the first time for our program and it was a nice change.


We do not have the PTO option but are considering it for this year.
Since we went ahead and bought a bit more transmission than we really needed for that year (3cim versus 2cim) we have the ability to add it easily.

I have run the transmission in 2 and 3 CIM configuration with no issues.

As mentioned, having a transmission module easily swappable can make or break a season. Plus you can easily modify gear ratios to get the perfect speeds / torque you require during prototyping.

We will be using them again this year and will be looking forward to doing some serious breaching!

Any question feel free to message me and I can video or Cads of our robot with the WCP WCD 3CIM transmission setup.

Good luck with this, and the season ahead.

Aloha!