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QUESTION:The application is a homebuilt skid steer, therefore there is
flexibilty of design. If I understood you right, the pump and engine
shafts would be parallel/side by side linked together with the roller
chain. I just thought it would be helpful to have the option of
disengaging the engine from the pump instantly via the clutch in an
emergency but perhaps it is not standard practice nor is it necessary.
How about the thought of a direct link between the crankshaft, either
from the flywheel end or the crank snout, and the pump input shaft? A
hard link or a flexible link as suggested previously? If a disengaging
mechanism is not needed, then a weldable spline adapter to a plate
bolted onto the flywheel would be feasible? I do have a small vertical
mill and lathe. I want the simplest most direct coupling in keeping
with the KISS principle if that is possible. Some pictures as you
suggest would be great!
ANSWER: The hydraulic motor has a GPM flow rating of 60. I have a Husco 3
spool valve rated @ 40 GPM I am thinking about using in a closed center
configuration. Not quite matched but I think the flow might be
adequate for the speeds I intend to operate this machine at -- about 7
miles per hour max I would think. Of course I would still have to look
at the circuit closer once I figure out the specs on the Sunstrand
pump. Upon closer visual examination of the pump, I was mistaken in
stating that the two hydraulic hoses originating from the control
valves piggybacked on the pump connect to the small gear pump at the
tail. In fact, those hoses communicate with ports at the lower portion
of the piston pump close to the base. Some sort of control for the
swash plate of the piston pump I'm thinkin'. If tha'ts the case, then
the small gear pump can probably be used to run my double action
cylinders therefore simplifying the circuitry into two separate
systems, main pump for the drive in a closed center configuration as
suggested previously, and the gear pump for the cylinders in an open
center type control. Your suggestions on the sizing of the control
valves and cooling for the fluid are highly valid and appreciated, they
will be incorporated in the final design.
With reguard to the power source, depending on the GPM flow of the
pump, your point on the use of a transmission intermediate to the pump
may be necessary indeed. If the pump flows 40 GPM, a guesstimate on my
part, my engine would have output at least 80 HP at 1800 RPM roughly,
allowing for inefficiencies. I have the formula somewhere but have not
done the calculations on that yet. Can my 283 CI V-8 engine meet this
need, I'd have to just try and go at it, dyno testing is out of the
question on this low budget project. If not, I'd have to use a
transmission to obtain gear reduction.
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