New Holland CX720 Repair Manual page 2787

TRAVELLING - 2WD-4WD SYSTEM Hydrostatic
Motor - Static description (D.14.E.28 - C.30.A.20)
Wheel Motor Operation
To start the drive cycle, hydraulic fluid under high pressure is delivered from the hydrostatic pump through the E-T II
valve and supplied equally to the high pressure port (1) of each motor. The hydraulic fluid is diverted through passage
(2) in the distributor block (3) and port (4) in the cylinder block (5).
The hydraulic fluid passage (2) and port (4) are partially aligned allowing oil to begin entering the cavity behind the
piston (6). The high pressure pushes the piston outwards causing roller to make contact with cam (7) just after the
peak (highest point) of the lobe. This contact causes the cylinder block (5), to start rotating.
1
20013707
Full Supply Position -
As a piston (and roller) (1) moves towards the bottom (valley) (2) of two cam lobes, the MAXIMUM (full) supply of
hydraulic fluid momentarily is directed through the aligned ports (3) of distributor (4) (remaining stationary) and cylinder
block (5) (rotating) with continuation on to the piston (1). The hydraulic fluid supply then begins to taper off as the
piston approaches the bottom of two cam lobes (2) towards a neutral (no power drive) position.
2 4/7/2006
D.14.E / 33