Doosan DX60R Shop Manual page 573

2. At High Speed
When you turn on the travel 2-speed switch, this will
actuate pilot pressure, which will move spools as shown
on the following figure. Then, pressurized oil will flow into
ports M1, M2, Pi1 and Pi2, having motor driving forces
(P1: high-pressure,
respective pistons controlling tilting plates. Consequently,
forces (Fp1 = Ap.p1, Fp2 = Ap.p2) which press tilting
plates will be created on the pistons controlling the tilting
plates.
At this time, l1, the sum of forces (F + Fs1), that, centering
on the rotational axis, influences the tilting plate, will be
less than l0, the sum of forces (Fpi + Fs2), that influences
those pistons, thus making the swash plate angle widest
and having the motor operate at high speed.
Figure 8
Travel Motor
P2: low-pressure) transfer to
SP001686
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