Hydrostac Drive

Dale in Nw wa · Jan 25, 2014

I dont have a Hydrostatic drive lawn tractor but I have a Question Are they driven by a belt or is there as pump that is hooked to the motor. I looked up some of the axles and they have a belt pulley on them. So KNOW I AM TOTALY CORNFUSED LOL Dale

Tom Arnold · Jan 25, 2014

Most of the lawn tractors use a vertical shaft engine that belt drives the trans-axle UNIT. Inside that trans-axle unit is a hydrostatic pump that pushes oil into a drive motor which in turn, applies rotary power to the differential gears.

These are self-contained units. There are some garden tractors with horizontal shaft engines that use a shaft to apply power to the hydrostatic trans-axle.

Hydrostatic pumps also have what is called a "charge pump" that keeps a constant flow of oil passing through the hydro pump to keep it full of oil as well as to provide cooler oil. On certain models of hydro trans-axles, there are ports leading to the charge pump and those ports can be used to provide hydraulic power for cylinders to raise/lower attachments, make a snow blade pivot right and left or allow power steering to be added.

You normally do not see this feature on lawn tractors but it is not unusual to find it on garden tractors.

Whether a belt or a drive shaft is used to connect the engine to the trans-axle, both are spinning the hydro-static pump.

Hopefully, the above will clear up your confusion.

jeffcat · Jan 26, 2014

Let us confuse him a little more. You understand direct drive."drive shaft" Then you have belt drive. "This is used on a he--l of a lot of lawn tractors. Hydrostatic is usually self contained in a housing as you described. The last is Hydrive. This is used on VERY heavy duty garden tractors. It is a BIG motor with a true hydraulc pump bolted to the engine shaft. Hoses go to a control valve and then to a true hydralic motor on a transmission. Look at any of the Case or Uingersoll Rand garden tractors. I have a 224 and it is a very interesting beast. Any more quesrions? Jeffcat

Tom Arnold · Jan 27, 2014

With all due respect..... your post tends to confuse things unnecessarily.

The Hy drive system which is employed exclusively on Colt, Case and Ingersoll garden tractors, is entirely different to "hydrostatic"drive systems. While both systems use oil to transfer engine power to the rear wheels, the design of the pumps are vastly different. Hydrostatic drives are a closed system whereas hydraulic drives are an open system. Both have their pro's and con's.

The question was entirely about hydrostatic drive systems. Injecting hydraulic drive into the discussion does little to answer the OP's original query, IMO. Secondly, the Ingersoll tractor company has no relationship to the other company known as Ingersoll-Rand. Yes, there is a similarity in name but that is the extent of it. However, that is a very common mistake that is made all too often.

My only purpose with the above post is to set the record straight so that anyone else reading this thread will not conclude that Ingersoll tractors were ever made by the Ingersoll-Rand corporation.

MNGB · Jan 27, 2014

Thanks Tom I agree 100%

Hydrostac Drive

Dale in Nw wa

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Tom Arnold

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jeffcat

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Tom Arnold

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MNGB

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