Gross HP vs PTO HP - HST vs Gear

[art]

Look at the posts here, this is not complicated. I thought there was some confusing information here from some of the posts. The point of this whole post before going off on designs and losses was Gear vs Hydro, gross horsepower vs pto horsepower. The hydro is less pto horsepwoer because it runs another hydralic pump for the hydro drive unit. The hydro units are bolted to the front of the rear differental on tractors instead of a normal multi speed gearbox. The hydro has different areas that it is more effective to operate in then the gear drive even with two horsepower less on the pto then it's matching gear drive. They both have people that like one style over the other. In the big tractor world they are trying to replicate the hydro features again to further enhance the productivity in farming.

 

[jrlichina]

Hmm, I thought that I had made that pretty clear in my previous posts..../forums/images/graemlins/crazy.gif

 

[Soundguy]

It is a dedicated unit.. possibly JD.. but could be ditch witch, or another similar company. It is a small tractor used for working roadside swales, and ditches. backhoe for trenching.. etc. keep in mind, this sin't farm equipment... I'm not speaking from any farm tractor hydro experience.. just heavy equipment. All my farm tractor stuff is gear.

HAs full hyd drive, on all 4 wheels.. engine drive shaft runs to the rear of the tractor and powers a large hydrostat pump.. that pump in turn powers everything else on the tractor.. steering, drive wheels, and a pto, which is obviously nothing more than a hyd motor...has a fluid in , and fluid out.. etc.

We've got lots of heavy equipment like that. At least one of our front end loaders.. a volvo ( go figure ) had a hyd pto on the rear.. and was full hydro drive.. computer controlled at that. One day the computer died on the job, and it wouldn't even move. Technician had to tell us on the phone about a manual diverter block on the tranny that could be screwed in , as a bypass, so that we would have hyd power to the wheels to get it on the transport.. etc... a real POS .. we sold it at auction after fixing it... I called it 'Lilly', as it was larger, heavier, more expensive and weaker than our JD loaders. Can't remember the model number.. but size wise, it was a tad bigger than a 544E

Soundguy

 

[art]

AS much as the shaft goes into the hydro's on the front it is probably just like those used on the compacts and the shaft also goes right thru the housing and connects to the PTO on the other side of the housing or uses a series of idlers off that shaft to transfer the power to the PTO unit.

 

[yellowsocks93]

The new John Deeres are nice with the IVT transmission. Still has a clutch and turning brakes but it's a hydro. I would rather have gears though as all of my tractors have been geared.

 

[Soundguy]

On the trencher it is hard to tell.. but the only connection between the engine and thee back of the machine is a drive shaft to a charge pump and master pump..( charge pump is belt driven off pulley(s) on driveshaft to master pump.) no other belts in the rear. There are belts in the front for a fan /alternator belt and powersteering.

On the reclaimer /miller tractor.. the pto is literally a hyd motor on back of the machine... we've removed it before to have it rebuilt. Hard to say about the others without a parts breakdown.. not saying it isn't.. but from the way the controlls and 'look' of the machine.. really looks like independent hyd pto setups.

Soundguy