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Donor Mower

After several months of researching and searching on Craigslist/eBay etc, I finally found a suitable donor for the mini mining truck build.

Jacobsen Greens King Kubota Diesel D662

That is a Jacobsen Greens King IV Plus Reel Mower. The reasons I selected this mower are:

-Kubota D662-EB 3 cylinder  diesel (19 hp/26 ft-lbs)
-Hydraulic Steering
-Hydraulic Drive

The engine is a good size. It's a lot narrower and shorter in length than a typical horizontal V-twin gas engine. However, it is a lot taller so I'll lose some ground clearance but I can deal with that. It's also liquid cooled so I'll have to deal with a radiator and fan. I still don't care. That diesel is going to sound cool.

The drive system is a little different than I am used to. It does not use a typical piston type hydrostatic pump (like I used on the dozer). It is actually a 5 section, fixed displacement, gear type hydraulic pump that is directly driven by the engine (3,400 rpm).
The first section is for the wheel motors. It is larger than the rest of the sections at 0.59 in^3/rev. The flow is regulated by a "traction metering valve" that is connected to the foot pedal. So it still "drives" like a hydrostatic pump. Direction is set via a valve which includes reverse, neutral, forward 1 and forward 2. Forward 2 will be explained below.

The remaining sections are all 0.38 in^3/rev.

Section 2, 3 and 4 each drive one of the reel hydraulic motors (the mower I purchased was missing the reels). Section 2 also operates the lift cylinders for the reels. Section 4, when not being utilized by the reel, is fed to the valve for the drive system. When put into speed 2 (called transport mode), the flow from section 4 is combined with the flow from section 1 which increases the speed of the mower. So basically it has a "2 speed" transmission. 3.7mph and 6.6mph respectively.

The final section is for the hydraulic steering.

I am most likely going remove pump section 3 and 4. I'll keep section 2 to power the lift cylinders for the dump bed as well as the second speed. I'll also remove the 3 reel motor control valves since I won't be needing those. I plan to do this while the mower is still together so I know everything works. Luckily, Jacobsen has a ton of documentation available for this mower.

The original hydraulic schematic is shown below (Source)

The modified hydraulic schematic should look something like this.
Also, due to the larger tire diameter I plan to use, the current wheel motors will need to be replaced. The have a displacement of 11.9 in^3/rev. I'll have to use something around 19 in^3/rev to keep it at a safe speed. I'll gain more torque because of this so that is a plus. And in case you are wondering, the wheel motors are in parallel so they act like an open differential while going around corners.

Once I'm done modifying the hydraulics, I will need to disassemble the mower so I can get the dimensions I need to continue the design.

That is all for now. I hope to start making more frequent updates soon.


*Source of hydraulic schematic courtesy of Jacobsen (Link)