Re: New AndyMark Gearbox
 

I have to agree, it's really a shame Andymark doesn't make better use of polycarbonate or other materials in their gearboxes for weight reduction. Our team has made several polycarbonate frame gearboxes over the years and after using them for 3+ years a piece we find the gears wear out long before the frame does (Yes, they were greased).

Unfortunately custom gearboxes can be extremely resource intensive to build and so the past few years we've been using Andymark gearboxes (which don't get me wrong, work great, but are heavier than they really need to be IMO). =/

Re: New AndyMark Gearbox
 

This is the 17 tooth gear used in the sonic shifter. It is used on the cim motor.

Re: New AndyMark Gearbox
 

The first stage would become 35:17 instead of 40:12. Knowing that the second stage can be either 28:35 or 35:28, and the third stage can be either 48:17 or 45:20, you should be able to figure out the closest overal gear ratio to the range you're looking for. Play with some gear ratio numbers - it's fun.

Re: New AndyMark Gearbox
 

Perhaps I'm the only one that ever worries about this, but CIMs can and do overheat when they are run in back to back final matches with polycarbonate (or ABS for that matter) gearbox plates. We had problems with overheating in plastic gearboxes in our 2008 and 2010 robots. To this day, I'm still mildly surprised that so many teams ran the VP ball shifters with minimal overheating issues this year.

Re: New AndyMark Gearbox
 

A can of compressed air turned upside-down solves this problem relatively easily.

Re: New AndyMark Gearbox
 

You're not the only one. CIMs that get hot take a while to cool down again. Many people are surprised to learn that a CIM that is only warm to the touch on its surface can be really hot on the inside. A while ago I posted some data from fairly extreme testing of a CIM on one of my dynamometers. During that testing the CIM was mounted on wooden blocks, so that not much thermal conduction was available to cool it and no forced convection; during the test we maintained the dynamometer loading near the peak of the motor's power curve.

It is a very good thing that FRC events include mandatory time outs before and during the final matches -- these motors can take a lot of abuse, but they DO need time to cool off after being driven hard. And I really love seeing them driven hard. This year my team put three CIMs on each side of our drive train, and our coach told the driver to drive the wheels off the 'bot. Which he did. :)

Re: New AndyMark Gearbox
 

From someone who used Ball Shifters and other various Vexpro products this season and was left with a very sour taste, I'll suck up the slight weight difference to use them and not worry about my gearboxes possibly failing during elimination rounds.

Looks good AM, can't wait to use these!

Re: New AndyMark Gearbox
 

I wish it was a little more competitive with the Vex pro ball shifter price and weight but It looks good for the teams that stick to AM. It would be a good thing to spend the 450$ KOP coupon on.

Re: New AndyMark Gearbox
 

(emphasis mine)

I'm pretty sure AndyMark is capable of making a much lighter version of the sonic shifter--but not at this price+durability. Likely the bulk of the orders they get will be from teams that don't have particularly tight specs for drivetrain weight, or maybe don't spec drivetrain weight at all.

This type of talk is good, though. Hopefully all students leave FIRST thinking they can do a better job with design/build than (insert product here)!

Re: New AndyMark Gearbox
 

We've had bad luck with aluminum and polycarbonate. In a world of over-zealous students who don't understand tolerances and alignment, I'd much rather have something that's over-engineered and pretty much bullet proof. In fact, we replaced the front of every polycarbonate toughbox with aluminum because students over-tightened the fronts and shattered them.

Yeah, yeah, I know, our students should learn better. They usually do, after they mess up once. We joke that if we're within 1/16" of an inch then that's pretty darn good. AndyMark products can tolerate that and then some, which is why we love them.

Re: New AndyMark Gearbox
 

On another note, I love the milled down top and bottom plates, however that rules out drilling and tapping into those for bottom mounting. So, I really hope AndyMark offers a bracket like VexPro does to mount these. right now, the only 'easy' mounting method I see is face mounting for a west coast style drive.

Re: New AndyMark Gearbox
 

Or you could mount it like we always have.

See post 20! ;)

Re: New AndyMark Gearbox
 

For those of you concerned about the weight of the Sonic Shifter, There are some very 'easy' ways to pull some weight out - depending on which gear ratios you go with. Hypothetically, if you were to swap out the larger gears to their Aluminum Equivalents from WCP - specifically the 40T Cluster Gear, 48 or 45T Final Stage gear, and the 48T Output gear - you'd save yourself an 'easy' ~.5lbs per transmission. If you wanted to go deeper into the transmission, you can swap out the output shaft with an aluminum version and save yourself another .2lbs or so and the list goes on. There's also the possibility of being able to swap out both the upper and lower plates for a simple round spacer to save another few tenths of a pound, but without knowing the exact measurements, it's hard to say (IIRC, on the Super Shifter, swapping the 'case' out for (4) spacers saved something like .5lbs)....

In any case, the point here is that this transmission really isn't that heavy when compared to the VexPro Ball Shifter, which weighs in at 3.05lbs versus 3.50 for AM's sonic shifter pre-lightening. The bonus with AM's shifter is that with it being an AM product, many of it's internal parts are the same as what's found in their transmissions over the last 4-5 years, so in the off chance that you need a spare or want to play around with ratios, you've probably got what you need to make it happen.