Question on hydrostats

[Texasmark]

Seems like a popular topic today is Hydrostatic transmissions. I have them on my ZT lawnmowers and they work great so I'd agree on their functionality.

Question is speed/flow control. With my ZTs I move the handle and hold it with my hands/arms to control the flow. No big deal. On my current tractor I have a regular geared transmission, a shuttle shifter for fast F-R work, and a hand operated throttle to control the speed once I get setup where I want to be.

With a Hydro, do you have to keep your foot in one place to hold your speed, or do you have linkage from the foot control to a hand operated lever that is friction set to stay where you put it?

Just thought of another question: Since the foot control apparently controls the flow rate what about engine rpms? Do you set the throttle at PTO rpms and leave it for the duration?

Just curious.
Mark

 

[k0ua]

Seems like a popular topic today is Hydrostatic transmissions. I have them on my ZT lawnmowers and they work great so I'd agree on their functionality.

Question is speed/flow control. With my ZTs I move the handle and hold it with my hands/arms to control the flow. No big deal. On my current tractor I have a regular geared transmission, a shuttle shifter for fast F-R work, and a hand operated throttle to control the speed once I get setup where I want to be.

With a Hydro, do you have to keep your foot in one place to hold your speed, or do you have linkage from the foot control to a hand operated lever that is friction set to stay where you put it?

Just thought of another question: Since the foot control apparently controls the flow rate what about engine rpms? Do you set the throttle at PTO rpms and leave it for the duration?

Just curious.
Mark

Lets see, you can operate the hydro pedel entirely by your foot, or if that gets tiresome as when you are running at the same ground speed for a period of time, as in mowing or going down the road, you can engage the "cruise control". Some work just as you described a friction lever, and some are electrical/magnetic. In other words a big magnetic coil that holds the pedal down at the preset position. This is how my Kioti works. As for RPM's many of the later generation hydro units can have an "auto-throttle" application that when you press the hydro pedal it automatically spools up the RPM's on the engine and then lets it go back to a preset position when you back off of the pedal. Not all have this, but generally you can set the throttle from 1500 to Wide Open as you see fit and still operate the hydro. Obviously when you need more power/torque, then bump up the throttle, and if you need less you can lower it. If you are mowing and need to run the mower at the 540 PTO position, then that is where you would set it. For a good understanding of the many features of the Kubota HST+ transmission and increasingly more manufactures are following, you can click on the URL below.

Kubota HST-Plus Transmission - YouTube

 

[SSdoxie]

The foot pedal on the HST tractor works same as 1 lever on your ZTR, father you push it faster you go. The throttle is independent, not connected to your foot control so set that at whatever RPM you wish to run at. Best not operate at real low RPM so the charge pump as sufficient flow to keep hydro pump under full charge pressure. I haven't a hydro tractor with a hand operated travel control but may be some out there. Mine has a mechanical "cruise control" that can pull up and lock the pedal in place after I step on it to hold the speed when want. I use when bush hogging the pasture sometimes.

 

[lt190b]

Here is another question. Is anyone other than kubota making a 3 speed,hi/lo split, hydrostat? lt190b

 

[lutt]

Here is another question. Is anyone other than kubota making a 3 speed,hi/lo split, hydrostat? lt190b

that's a good question, I havnt looked at new tractors in a while, my 2001 model 4200 deere has H/M/ and low ranges and it's a hydro. It stays in the medium range 95% of the time. If I were buying a new one, I would want all 3 ranges again. LUTT

 

[k0ua]

Here is another question. Is anyone other than kubota making a 3 speed,hi/lo split, hydrostat? lt190b

I believe some of the Shibaura build New Hollands had a turtle/rabbit switch with a 3 range hydrostat.

 

[lt190b]

I believe some of the Shibaura build New Hollands had a turtle/rabbit switch with a 3 range hydrostat.

kOua, the pre CVT tractors have a 2 speed with hi/lo. Is there newer ones that have a 3 speed with hi/lo? what model? hp? lt190b

 

[k0ua]

kOua, the pre CVT tractors have a 2 speed with hi/lo. Is there newer ones that have a 3 speed with hi/lo? what model? hp? lt190b

I was thinking the TC45DA had a 3 speed hydro with the turtle/rabbit.

I dont think any of the modern NH tractors do.

 

[RaydaKub]

Lets see, you can operate the hydro pedel entirely by your foot, or if that gets tiresome as when you are running at the same ground speed for a period of time, as in mowing or going down the road, you can engage the "cruise control". Some work just as you described a friction lever, and some are electrical/magnetic. In other words a big magnetic coil that holds the pedal down at the preset position.

My BX (2004 vintage) has 2 sets of saw teeth, one fixed, the other on the pedal linkage. When you engage the cruise, the sets of teeth are pressed together. When you press the pedal farther (and there will always be a "farther" because the teeth hook and slide backwards to engage) the tension on the rod relaxes and the teeth fall apart.

 

[Texasmark]

Ok guys, thanks for the info.

Mark