222's TigerDrive
 

What has 68 individual parts, 2 speeds (Ball-Lock Shifting), 2 motors, is smaller than Kit of Parts (KOP) single speed transmission, and appears to shift like magic?

It's the Tigertrons 2006 TigerDrive Transmission!





Main Differences from the 2004 and 2005 222 Ball-lock transmissions:

MUCH smaller in size, even smaller than the single speed transmissions included in the kit of parts.
Two CIMS instead of just one per side.
Bearing added to allow for free rotation of the "Shifting Spool"
It has less gears but nearly the same ratios.
We went from having seven gears down to six, two of which are stem pinions on the CIM motors.
Weight of the transmission housing is much lighter.
Much more simple design.
Less custom fabricated parts.
Bearings throughout instead of bushings.
Easier to build/repair/inspect.

"It's small, it's light, it's genius, it's TigerDrive , and it puts the Roar To the Floor!"

2 CIM Motors
2 Speeds
2 Small

TigerDrive Dimensions

Re: 222's TigerDrive
 

Very nice, Any clip's of it shifting id be interested in seeing it in semi-action. Also what were the gear ratio's you used 1155 is looking to make our own shifting transmission in the preseason next year and was planning on using a similar motor to gear set up.

Re: 222's TigerDrive
 

I am realy impressed by how compact the design is. The placement of the cylinder is interesting, too. Looking at the 2004 and the 2005, I would have to say that the improvements are very noticeable. What's the gear reduction on this year's transmission?

Re: 222's TigerDrive
 

All I have to say is....that thing is sweettttttt!

Re: 222's TigerDrive
 

For some reason this looks very familiar ... Brad pointed this out to me last week. Great tranny team 222...

Re: 222's TigerDrive
 

Do you plan on releasing a white paper specific to this model of the TigerDrive, or is it similar enough to the 3 speed where it can be custom modified into a smaller, lighter 2 speed version (as shown here) without a PE in mechanical engineering?

Re: 222's TigerDrive
 

Gear reductions are as follows:

Transmission output in Low Gear is 10.9:1
Total output to wheels in Low Gear is 54:1 for slightly less than 4fps.

Transmission output in High Gear is 3.64:1
Total output to wheels in High Gear is 18:1 for 11fps.

We don't have a close up video of it shifting, but you can see how it performs by watching Match 70 from VCU

Re: 222's TigerDrive
 

Love 222's ball shifter. Nice refinement. Now if you could get it to shift with a servo that could free up a lot of weight for years when air is not needed. Also I've always looked at the round recess in the gears and wondered about the forces on the gears and balls when engaging and disengaging. Would a v slot work better?

Re: 222's TigerDrive
 

We went with the design that the Hodaka motorcycle had which was the ball shape. It hasn't given us a problem, ever, so why fix it if it isn't broken :p ?

As far as the cylinder vs. servo:
It has been discussed here on CD somewhere before but I still hold the KISS belief in mind. In. Out. No question. A servo can do it, but I personally don't want to risk a low back up battery costing the team a match. Plus with how much I shift out on the field, we would probably have to switch backup batteries every match. Thats just another thing to worry about when we don't have to.

Re: 222's TigerDrive
 

Niiiicccee! It's two times smaller than ours...lol

Re: 222's TigerDrive
 

Very, very nice transmission. The compact design is fabulous. The reversed direction pneumatic cylinder is a nice twist to save space. I do have some questions:

1. What made you switch from bushings to bearings?
2. Why use collar clamps on the CIM shafts as opposed to steel shaft clips (like the ones used on the Kit Transmission)?
3. Are the CIM gears pressed onto the CIM shafts?

This is definitely another outstanding design coming from the Tigertrons.

Way to go!!

Andy B.

Re: 222's TigerDrive
 

1. We switched from bushings to bearings for a couple reasons. The first reason was simply to increase efficiency. The second reason is because bearings worked out very well for our input cluster. Bushings were a simple and cost effective method for 2005, but were not the best way to do things on a high RPM gear cluster.

2&3. The gears on our CIM motors are not stem pinions. We had planned on stem pinions and using another bearing in the plate opposite the CIM motors, but decided we could save some weight and headaches by switching to a regular gear. the reason we have collars on the CIM gears is to 'pinch' the gear onto the shaft. We did this mainly because our team doesn't have any metric broaches and we didn't want to modify the CIM shaft. We have used this design previously in 2004 and it worked very well for us.

Thanks all for the kind compliments! Transmissions like this only happen when enthusiastic STUDENTS get involved in the design and build and constantly push the team to do better! Thanks Henry and Bunney you guys put in alot of time convincing the team we needed a dual motor drive and even more time machining your wishes. ;)

Re: 222's TigerDrive
 

Thanks Cliff for believing in us! ;)

Re: 222's TigerDrive
 

I thought somebody told me once that you were running 20 pitch 11 tooth pinions on the CIM motors and the reason for those clamping collars is that you cannot fit a keyway because the "wall thickness" between the root diameter and the bore diameter is so thin. I might be dreaming though. I can't remember.

Re: 222's TigerDrive
 

yup you are correct I just looked at the measurements last night.