Shift on the fly: cone clutch? dog engagement?

[nsmith40]

I'm looking at implementing a 2 speed gearbox after a belt driven CVT transmitting 15 HP max. The RPM from the CVT will max out at 5000 rpm and the low gear reduction is about 1.5 times the high gear reduction.

I would like to shift between the two gears on the fly, and I would like to avoid a disengaging clutch for simplicity reasons. I am currently looking for the best way to handle this. Would a dog engagement suit this situation well? Perhaps a cone clutch? Perhaps something I'm not thinking of just now?

Thanks for your thoughts!

 

[MikeHalloran]

Planetary reducer + bands.

Otherwise you need to remove the torque to make the shift.



Mike Halloran
Pembroke Pines, FL, USA

 

[pontiacjack]

If you aren't already committed to a particular gear-reduction scheme, I would investigate a planetary-drive. If configured correctly- a one-way sprag on one of the elements and a friction lock (like a band) on another element- it can be shifted on-the-fly by applying/releasing the friction lock (an over-center link works well to lock a band).
If on-the-fly means you would settle for letting off the throttle to shift one direction (like old car overdrives), a pawl could be substituted for the friction lock.

 

[pontiacjack]

Darn it, Mike! Although we apparently think alike, you must type faster than me!

 

[patprimmer]

Agree with both the above.

See "T" model ford for example.


Regards

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[RossABQ]

Laycock deNormanville O/D as used on several Euro cars in the '60's and up into the '80's would be just the ticket. It uses a hydraulically actuated cone clutch to engage a planetary gearset. Bolts onto the back of a standard trans with modified output shaft.

 

[evelrod]

Ross, the LdN O/D was fine, back in the day. Rather rare and parts are difficult to find at a reasonable cost. Also extremely heavy and a bit over engineered for a "15hp" input!
If weight is not the problem, GearVendor of San Diego makes several two speed conversions adaptable to a multitude of uses. At only 15hp, I think I would dig through the industrial gear vendors catalogs, or do a lot of Google.

Rod

 

[MikeHalloran]

I was thinking of hacking a junkyard Powerglide.



Mike Halloran
Pembroke Pines, FL, USA

 

[evelrod]

Yes, I like the "hacking a junkyard Powerglide" except for the "junkyard" part. I spend (waste?) a bit of time in Socal junkyards and I haven't seen a Powerglide tranny in many years. Many, many years. Seems all the hot rodders have used them up. My neighbor finally found one attached to a 283 and bought the 'package' for his '65 Impala. Rebuild was a 'piece of cake'! Since we are dealing with something difficult to find in the first place, my choice to "hack" would be a pre '50 Hydromatic...the one with the mechanical reverse and no 'park' position. Either would still be pretty 'beefy' for only a 15hp input.

If your looking for a tranny to "hack up" for any reason, try the local taxi company. Out here the Yellow Cab service yard in the LA area (I think it's Gardena) has about a zillion junked transmissions out back.

Rod

 

[IceStationZebra]

I can think of two other options.
1. A variable sheave set up with linkage that only allows two positions. (here is one vendor

http://www.lovejoy-inc.com/uploadedFiles/Catalogs/vsd.pdf

to give you an idea)
2. Some of the late belt drive Bobcat's had a two speed option. I believe that to engage high you energized a clutch, and low then spun on an over-running/sprag clutch. Of course you could use chain or a toothed belt, but the belt should allow for some slip during "gear changes".

ISZ