Re: 90 Degree Gearbox?
 

Resurrecting a "dead" thread, but between the 192 90 degree gearbox and the 971 simply-put-motors-in-opposite-direction solution, which is more viable? I can pick this up as a project for my team and work on it this semester. I'd like to look into ways to keep the CIM from pointing directly into the middle of the robot. Being a former Head of Electrical, you can imagine I know how cramped it gets in the middle

Re: 90 Degree Gearbox?
 

The method 971 employed is easier as it's still just spur gears.

Re: 90 Degree Gearbox?
 

Alright. Are there other methods of reducing the footprint of a CIM motor besides the ones mentioned? (90 degree gearbox and flipping the direction the motor points) There are the various swerve modules that cut down on the footprint but I'd rather leave the complexity of making wheel pods out for now. I'm sure I'll get to that eventually, but not at this moment. One of our mentors mentioned running the motors via shafts, ie the same method cars use for their drive (albeit without the ackerson drive). Any thoughts on something of that nature?

Re: 90 Degree Gearbox?
 

This is certainly an "out there" suggestion, but you could theoretically mount the wheels such that they rotate around the CIMs, as if the CIMs were a dead shaft. I'm sure the next person on the thread will have the link, but I remember seeing pictures a few months back of a swerve drive setup that did just that.

I really don't think you should worry too much about the footprint of the CIMs inside the robot. It's a lot more simple to re-arrange electronics to fit around CIMs than to design and spend lots of time machining a fancy transmission to save a bit of space. I saw 192 at SVR, and they really didn't use the extra space that they got with that type of gearbox. That said, if it's absolutely critical to not have the motors sticking into the frame, I would recommend the 971 approach.

Re: 90 Degree Gearbox?
 

You know, I was thinking the same thing a few hours ago too but decided it was a little impractical.

Re: 90 Degree Gearbox?
 

3298's ran their swerve like how you describe. I've looked into it and decided it was a bit much for solutions. Though it'd does beg more thought for doing it but sans swerve...

It's not that I'm incredibly worried about the footprint of motors, but it's a nice thing to eliminate.

I'm taking what is basically an independent study for robotics for ~2 hours a day this semester so I figured that the next 5 months would be a great time to invest into some of the "out there, but do able, and has pay off value" ideas we never do during season. PM me for more details or if you have suggestions on other projects

Re: 90 Degree Gearbox?
 

There is no rule that says the drive chains have to be on the inside of the wheels. Toothed belts can also be used to change direction on drive components without the loss in other methods.

Re: 90 Degree Gearbox?
 

It really is shameful how under utilized the space was used this year. That gearbox stemmed from previous years of gearboxes practically meeting in the middle of the robot and my taking to making things take up less space. It would have been perfect for a double pick up or ball storage low down.

Re: 90 Degree Gearbox?
 

Back to the original topic, I remember seeing a 90 degree drivetrain that was built by 1075.

I don't remember the specifics, but the CIMs were completely captive within the drivetrain side rails. It was very elegant and space-efficient.

Does anyone recall, or have more information on what they did?

Re: 90 Degree Gearbox?
 

Attached is a picture of 1075 from our Facebook page. It would appear their CIMs are mounted vertically to assist with interfacing to their swerve module.

Re: 90 Degree Gearbox?
 

Sorry, I should have mentioned that this was a few years ago - prior to 1075's recent swerve drives. I want to say it was at least 3 years ago?

I recall having a student talk about them in great detail... and when I asked him where the motors were mounted, he showed me that they were embedded longitudinally within the siderails themselves.

Re: 90 Degree Gearbox?
 

1075 has been doing swerve since 2009, so it must have been 2008 or prior. Sorry for the confusion.

Re: 90 Degree Gearbox?
 

In 2005 we installed our CIM inside of our drive wheels. It saved space but required allot of time for design and trouble shooting. We did find the solutions to our problems but it really came down to having the money to do it correctly.

The project we are working on now also requires a right angle connection (as discussed in the earlier threads) from the CIM to the drives. I am looking at a "face gear" which seems difficult to find with out spending allot of money. I was hoping to use the standard pion gear on the CIM and get a 2.5 - 2.75 face gear which would attach to a belt drive sprocket and then to the drive wheel. . Is anybody familiar with face gearing? Any input would help greatly. I wished Andy mark had a ready to use right angle gear box (other than the worm box).

Re: 90 Degree Gearbox?
 

I would probably go with a metric bevel gear off the CIM rather than a face gear. Just make sure it has a keyway rather than a set screw.

In any case, as I've described before on this thread, space saving measures are not really worth fighting all that hard for. They're great if they come from the geometry of your gearbox, but I wouldn't stress it in other circumstances. If you really need the space for something, there are better options than a face gear, as described in this thread.