How do RPM,pedal and gear relate

[Mickey_Fx]

Thanks all for your input. Still not sure how HST pedal, gear shift and hand throttle interrelate. Mike: Appreciate your safety tips. I will use the brake now that I almost had the ck roll over my foot on a very slight incline. Also, I now dismount on left only as on two occasions I have accidentally turned off the key while getting off on right side

Jay

Will try and answer your question. My comments are general in nature so may not be 100% accurate for any specific model.

An HST is a hydralic transmission, there are no gears. How a typ HST works is they have a variable displacement pump and a fixed displacement motor. Your foot/speed control changes the displacement of the pump. For any given engine speed, changing the displacement will change the speed of the hyd motor. The output shaft of the hst pump is the input to the rest of the trans/differential. You have several gear choices in this section of the trans.

Typ when you "gear" down you increase the torque at the output. But with a HST and it being hydralic, it has an over pressure relief valve. No mater where the speed-control/foot-control is, once the max presssure is reached, oil flow gets diverted through the relief valve. Backing off on the speed control will not automatically result in being able up the tractor load.

To sum it up, engine speed will vary the output speed of the trans, changing the speed control on the HST will change the outpt speed of the HST and changing the range will change the speed of the tractor and vary the max torque at the output of the trans. Peak torque will be limited by the relief valve in the HST.

As to the pto shaft, I'm not sure how it is driven but I would suspect it isn't driven through the HST's pump.

 

[RedRocker]

Redrocker, when you say to really dig or push go to low range. Are you talking about when you use a backhoe to dig or the bucket to dig with.

Bucket, I'm backhoeless myself.