Tractor with two wet clutches PTO and transmission.

JC-jetro · Feb 26, 2008

Howdy all,

I'm thinking out loud here.. does anyone know any compact utility geared tractor that has independent pto, with two separate hydraulically activated multi disk wet clutch. I was thinking, if one can design a tractor to eliminate splitting of tractor for clutch change and few other advantages. Please look at the sketch I made below. You'd have a different (probably more stout) clutch housing that only houses a heavy flywheel, main drive shaft thru couple of layshaft and gearing to provide rotational torque to two separate hydraulically actuated wet disk. You'd be able to remove the clutch pack from top or side of the housing for replacement. Tractor splitting would not be necessary as you would have splined coupling that would slide on both driving and driven shaft (clutch input and output shaft) with set screw if needed. In other word one could drop the clutch in the housing with the couplers slid to the opposite direction, once the housing is secured then you slide the coupling in place and tie it down with set screws if needed. Has anyone seen anything like that? I know on some big AG tractors the main clutch are wet multi disk for shear robustness and long life. With a setup like that maintenance of non-hydro tractor can be quite a bit easier. Please give me you opinion.. I may be going off the deep end here but the question been bothering me for a while.

Thanks,
JC,

P.S , Obviously nothing scales out and there are many parts missing. the sketch below is at best diagrammatic to explain and show my idea.

JB4310 · Feb 26, 2008

Hey JC,
I'm not gonna touch that one as it is over my head, but just wanted to say hello and keep up the progressive thinking.

John,

JC-jetro · Feb 26, 2008

Hi John,

Glad you looked at my thread. Man... I'm not getting any bites at all. May need to chum the water to attract some big fish.

I know they are out there

JC

DuaneW · Feb 28, 2008

Dont know about a compact utility, but OLIVER tractors have their PTO clutchs on the back of the tractor, and are a live PTO. This is accomplished buy running TWO drive shafts from the motor, an inner shaft and an outer (hollow) shaft. The innershaft runs the Hydraulic pump and the pto, the outer shaft is the transmission shaft and uses a clutch mounted on the back of the motor. You can change either set of clutches with out haveing to break the tractor in half, but you do have to pull the motor to change the transmission clutch. Have been told that once youve pulled a motor on one of the Olivers, the second one you can have on the ground in under 2 hrs.

DuaneW.

BobG_in_VA · Feb 28, 2008

I kinda think you're trying to come up with an answer to a question that hasn't been asked yet....Your "thesis" sounds just like a motorcycle clutch (wet multidisc, etc) pack. Most well built tractors can/will go over 6000-10000 hours (read also as from 15-50 years on the original clutch) using it hard...Motorcycle clutches were designed to be able to actuate using very little force/mechanical advantage-- "weak springs" and multi plates(ie. your hand power). The mechanical advantage of large/HD multi-spring pressure plates is required for the shock loads found on tractors (weight of the tractor/PTO loads etc). Yeah it might be easier to change out a side mounted clutch pack, but you'd be doing it about every month vs. every 3 or 4 decades...just my $.02 worth...good try though... BobG in VA

BobG_in_VA · Feb 28, 2008

Oh, just an aside, but check out the clutch set ups on the old John Deere 2 cyl engines (A's and B's, etc). Dry clutch on the side that you could change out relatively easily...only problem was it was a hand clutch. Don't know it you ever ran one but both feet and both hands were used to operate them. One brake on each side for your feet, right hand for the the clutch and the throttle, and left hand to steer...one of your hands to change gears, oh and the starter was actuaed by your foot as well. But,,,,the clutch was relatively easy to change out. BobG in VA

Soundguy · Feb 28, 2008

Bob.. i remember the day when i got my JD-B.. boy I was stomping hard on that left brake as i was pulling into the barn... glad i remembered the hand clutch!

As tot he original question... So far.. looks like you want a 'wet' main clutch, and a wet pto clutch.

I see lots of dry mains/wet pto's.. as another poster stated.. with proper care and feeding.. both should last a LONG time. My 5000's a 75 model.. it's seen alot of work. main and wet clutch are starting to show wear... probably a few more years down the road and she will need work...

soundguy

Farmwithjunk · Feb 28, 2008

The average life expectancy of a tractor clutch would probably out weight the need for a "cheaper-simpler" clutch replacement procedure. A completely new, differnt design concept would add to the bottom line of any new tractor. Add that increase to the initial purchase price, vs. spending it on splitting the tractor for a new clutch 10, 15, even 20 years into the tractors life, that increase would DECREASE sales of that new tractor. Manufacturers are not likely to want to go that route.

A new "clean slate" design might have some chance of incorporating a different type of clutch. But then again, will that new design price out in line with current "typical" tractor power train concepts? Tractor builders surely want a low maintenance cost as a selling point, but not at the expense of a much higher initial price.

It's an interesting thought, but the practicality and cost to incorperate the design into a production tractor would have to be in line with current accepted practice before it'll be taken seriously.

JC-jetro · Feb 28, 2008

Gentlemen,

Thanks for all the good replies. I knew there were some big fish out there after all to take a bite

. Points are all well taken. I know what I proposed comes at quite a bit of initial cost and retooling for manufacturer but things always start from an idea. sometime they take a life of their own and more than not they fizzle to nothing. I thought with the concept I tried to portray along with couple of hydraulic master cylinder and power assist would make clutching much easier hence giving more value to gear design rather than HST. I have seen people damage clutch housing due to overworking their FEL. Although, sub frame mounted fel would keep the system from twisting and damage a clutch housing that was intended for a flywheel only can be cast differently and more stout than normal clutch housing with a relatively thin casing. I think I was reading literature on some Kubotas (+100 hp jobbies) and they were boasting on their design of multi disk main clutch. I need to go back and verify that, might have been pto ...not totally sure. On my little tractor after 30 years of use (not heavy use) and 1000 hrs the clutch disk looks as thick as original OEM. I have got nothing against the old design.. as they say " if it ain't broke, don't fix it".

Again, Thanks for all the responses. Appreciate it.

JC,