WHY HAVE A CHAINCASE ANYMORE?POLARIS FIGURED IT OUT

[rtx moose]

love the concept also

 

[srx700lt]

http://www.freevalve.com/

 

[chris189]

Yes we have done a few trips in the west and I can say those PRO 800's are amazing. NO....they do not all make it down the hill. Between electrical issues and belt drive issues. Yes we left one for sure half way down the mountain in Revy that had either broken driveshaft or......The rental place said...Oh....not another one.

 

[OVR4D]

SRX700lt posted a link to a pneumatic variable valve timing system, but what caught my attention was the video that followed. This is a link to a new type of CVT system, which could eliminate the need for drive (primary) and driven (secondary) clutches, a jackshaft and a chaincase. Given the current PTO design configuration of snowmobile engines, the motor would have to be transverse mounted in order to couple with the inventor's "D-Drive" transmission, but that would be relatively easy to do in a sled.

 

[srx700lt]

I missed that one, as I see it the CVT is the next logical step in the evolution of sleds. Combining the freevalve system with this cvt solution would give a much lighter 4-stroke engine without the limitations in rpm's in today's cvt systems.
Imagine the R1 engine in an apex replacement without the gear reduction. I think that would be interesting.

 

[Sasquatch]

SRX700lt posted a link to a pneumatic variable valve timing system, but what caught my attention was the video that followed. This is a link to a new type of CVT system, which could eliminate the need for drive (primary) and driven (secondary) clutches, a jackshaft and a chaincase. Given the current PTO design configuration of snowmobile engines, the motor would have to be transverse mounted in order to couple with the inventor's "D-Drive" transmission, but that would be relatively easy to do in a sled.

Nice! Guy is a mechanical genius. You do realize if you mount transversely that is the way the motor is mounted now, right! So I'll expand on that thought. The limiting factor is in the bulk of the transmission when assembled. ie how compact can it be say for a snowmobile installation. The prototype is for display purposes and does not need to be anywhere near that overall length. Move the motor over to the right (oil tank side a smidgen maybe) bolt the new trans to the engine where the gear reduction now resides and use either a belt, chain or gear drive direct to the drive-shaft. Drive clutches gone jack shaft gone and chain-case gone.

 

[meskie]

Simple planetary setup in the belt drive somewhere could achieve reverse without to much complexity. Kinda.

 

[OVR4D]

You do realize if you mount transversely that is the way the motor is mounted now, right!

Good Catch Sasquatch ... I know I wrote transverse, but I was thinking longitudinal. Just one of those brain fart moments. Anyway, I was noticing that one of the electric motors driving one of worm gear shafts in the prototype was mounted perpendicular to the transmission, and so my thought was you'd need to couple the motor in the same way. But as you point out, the transmission does not need to be anywhere near as big as the prototype, and there are a variety of ways to couple a motor to it.

This transmission prototype does have some flaws though. For one, it seems to require a way of varying the speed of one of the gear shafts in order to shift from reverse to neutral to forward. In the prototype, the inventor is using a variable speed electric motor to do this. But how would you do this with an internal combustion engine? Another thing is that it looks like the rotation of some of the larger gears would create a balancing issue. They move like planetary gears, but not really (not sure how to explain it any better ... I'm no mechanical engineer). The inventor sure seems like a bright guy, and I'm guessing he's thought through the things I'm pointing out ... and probably has answers for them.

 

[Sasquatch]

Good Catch Sasquatch ... I know I wrote transverse, but I was thinking longitudinal. Just one of those brain fart moments. Anyway, I was noticing that one of the electric motors driving one of worm gear shafts in the prototype was mounted perpendicular to the transmission, and so my thought was you'd need to couple the motor in the same way. But as you point out, the transmission does not need to be anywhere near as big as the prototype, and there are a variety of ways to couple a motor to it.

This transmission prototype does have some flaws though. For one, it seems to require a way of varying the speed of one of the gear shafts in order to shift from reverse to neutral to forward. In the prototype, the inventor is using a variable speed electric motor to do this. But how would you do this with an internal combustion engine? Another thing is that it looks like the rotation of some of the larger gears would create a balancing issue. They move like planetary gears, but not really (not sure how to explain it any better ... I'm no mechanical engineer). The inventor sure seems like a bright guy, and I'm guessing he's thought through the things I'm pointing out ... and probably has answers for them.

Problem with longitudinal is you then need a 90 drive and you still need a jack shaft to get the power from the middle to the outside to drive the driveshaft.

As for the motors (two of them one for reverse and one to control speed) to drive the transmission shafts they can be electric and small as they don't take any load from the engine. Although taxing the stator could be an issue. He mentions hydrolic or electric over hydrolic which would work in a car (think powersteering pump) but not so much in a sled.

They have used planetary gears in auto transmissions since the beginning of them, no balance issues I know of.

I would think that the system could have a speed issue and spinning it at 13,000 rpm with 180hp load (we want the full potential of the R1 motor right) would be a test indeed. For large earth moving or industrial machines this could work well, for automotive it allows smaller engines to remain in their powerband and fuel efficiency range. Like it or not as I read somewhere the future even for sleds could wind up being small turbo deisels, needing CVT type transmissions to work properly.

Amazing prototype he has designed I hope it makes it into a practical application.

 

[GT Mills]

Came across this old thread, and trust me a cog belt is nowhere near as good as a Hy-Vo chain for one very simple reason: Vibration. Cog belts create horrible harmonics, whereas "silent chain" was so named because it is so smooth - in fact far smoother than even gears!!! let alone crappy cog belt junk. Be thankful that Yamaha uses not just silent chain, but actually the very best silent chain available.

 

[Mills]

SRX700lt posted a link to a pneumatic variable valve timing system, but what caught my attention was the video that followed. This is a link to a new type of CVT system, which could eliminate the need for drive (primary) and driven (secondary) clutches, a jackshaft and a chaincase. Given the current PTO design configuration of snowmobile engines, the motor would have to be transverse mounted in order to couple with the inventor's "D-Drive" transmission, but that would be relatively easy to do in a sled.

The link says the video is unavailable. Was it taken down?

 

[paradise]

I’m sure it was taking down if it was something that they didn’t want us to see.

 

[Sasquatch]

 

[STAIN]

Very interesting…….

 

[rtx moose]

The link says the video is unavailable. Was it taken down?

Yamaha just patened a such drive!!!!