The Advantages of a Hydrostatic Transmission are: Ease of use. There are no levers to shift, no clutches to depress.
Infinitely variable. You can change have any variation of forward speed between 0 and Full. Compact size. Since there is no dependence on gear sets to multiply torque or change directions, the transmission is much smaller. A hydrostatic transmission applies torque smoothly and efficiently. Here are the key components to a Hydrostatic Transmission Transmission Case The case holds all of components in place and has passageways to move oil from the pump to motor and back again in a closed circuit.
Charge Pump The charge pump provides initial case oil pressure and fills the case and circuits with oil. Input Shaft The input shaft takes power from the engine and rotates the charge pump and the axial piston pump in the transmission.
Axial Piston Pump This pump is the heart of your hydrostatic transmission. Pressure Relief Valves The pressure relief valves offer an alternative path for oil to flow when the oil pressure reaches a predetermined amount. Axial Piston Motor This motor is what drives the output shaft as a result of oil flowing through it. Swash Plate The swash plate changes the displacement of the piston pump.
Check Valves Check valves keeps oil in the closed circuit loop between the pump and motor. See illustration The oil begins in the reservoir which is the rear differential case on the Cub Cadet Garden Tractor.
Thank you for saving the tractors, - Norman, iSaveTractors Sep 7th Facebook Email Print Twitter Pinterest. Recent Posts. Sep 10th iSaveTractors. The ability to detect, observe, and measure electricity is crucial when trying to understand how a ….
The engine is the heart of your garden tractor. When performing heart surgery on your tractor, be aw …. Glide shift transmission is exclusive to Kubota tractors. Kubota DT tractor models have a standard gear drive that includes eight forward gears and eight reverse gears. This transmission type forces you to use the clutch to switch between forward and reverse and to move through the eight gears. If you plan to use your Kubota tractor for jobs that involve a lot of forward and reverse movements, the requirement to use the clutch a lot in this transmission type could become annoying.
However, Kubota DT gear drive transmissions are fantastic for pulling loads. There is no need to hold down a pedal to keep the tractor moving, so they are great for traveling long distances. The learning curve is a little steeper, but if you are already familiar with gear drive transmission machines, this tractor type could be right for you.
To find out more about the various Kubota transmission types, contact Bobby Ford Tractor and Equipment today. Our tractor experts can help you find a Kubota that perfectly suits your needs. Click to Learn More. The greater the tilt of the swashplate, the greater the stroke of the pistons and the larger the flow from the pump - also, the more hp it takes to turn it, of course. The motor works the same as the pump, except that the fluid coming into it is spinning the block, instead of the other way around.
Also, in most HST transmissions, the swashplate in the pump can be pivoted over center in either direction. One way, the tractor goes forward - the other way, flow is reversed and it goes backward. Usually, the motor's swashplate angle is fixed at an angle about half-way between its maximum and minimum angles. At least one CUT has a "high torque" mode that forces the motor to maximum displacement maximum swashplate angle. On my EF-5, both the pump and the motor have completely variable swashplate angles - which gives it almost as great a speed range as a CUT without any mechanical gearbox or "range selector".
Picture the pump turning with a very small swashplate angle - very little flow will be produced, and the motor turning with a very high swashplate angle - maximum flow is required to turn the motor, which results in a very low "gear" with very low speed and very high torque. On the other hand, if the pump is turning with maximum swashplate angle, producing the most flow it's capable of, and the motor is set to minimum swashplate angle, requiring very little flow to cause it to spin, you have the equivalent of a very high "gear", with high speed but with low torque.
There is also an override on the EF-5 that forces the motor into highest-displacement high torque mode. So why don't all CUTs use variable displacement motors and do away with the range selectors?
Cost is one factor. Also, motors aren't equally efficient at all swashplate angles so, while they can produce almost as great a speed variation as tractors with 3 ranges, they're not as efficient throughout the entire range.
There's no free lunch. Personally, so far, I think I prefer the variable displacement motor to the gear range selector, because I never have to stop to shift, it's always in the right "range" depending on how fast the engine is turning and how much work I'm making the machine do, e.
One other disadvantage of the purely hydraulic approach is that you don't usually get quite as much range - my EF-5 has a top speed of 13 mph measured , whereas the L would go 16 mph.
Now that I've totally confused you, you can probably appreciate the links MossRoad posted a lot more. Jan 13, Thread Starter 6. Jan 13, 7. Harv - Glad you got something out of it. Back when we used to have "HST vs. I guess one of the things that most amazes me about it is that I don't think it would ever have occurred to me to generate force in that way.
A really radical concept. As you said, pure genius. Jan 13, 8. TresCrows Elite Member. Here is a pic of a turbine engine hydro pump with variable displacement. Imagine two pumps, one fixed output and another variable driven as a motor from the fixed, then you have tractor HST.
Jan 13, 9. Another pic of hydro pumps, one fixed and the other variable.
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