Hydraulic Flow Diagrams; Traction Forward And Reverse - Toro Greensmaster 3200 Service Manual

Hydraulic Flow Diagrams

Traction Forward and Reverse

Forward
The hydrostat is driven directly by the engine. The trac-
tion circuit of the hydraulic system acts essentially as a
closed loop. Taking its suction directly from the return
side of the wheel motors of the traction circuit, the hy-
drostat supplies oil flow to the wheel motors through the
supply side of the traction circuit.
With the engine running and traction pedal in the neutral
position, the hydrostat supplies no flow to the wheel mo-
tors. When the traction pedal is pressed to the forward
position, the linkage from the pedal positions the swash
plate in the hydrostat so oil flows out the bottom port of
the pump. Oil flow out of the bottom port goes to the
wheel motors and turns them in the forward direction.
Oil flowing out of the wheel motors returns to the top port
of the hydrostat and is continuously pumped out the bot-
tom port.
Hydraulic oil is supplied to the traction circuit from the
gear pump (P2) though the steering control valve and
back through the charge circuit check valves. This oil re-
places oil losses from flow through the case drains and
small amounts of leakage.
Hydraulic System
Reverse
The traction circuit operates essentially the same in re-
verse as it does in the forward direction. However, the
flow through the circuit is reversed.
With the engine running and traction pedal in the neutral
position, the hydrostat supplies no flow to the wheel mo-
tors. When the traction pedal is pressed to the reverse
position, the linkage from the pedal positions the swash
plate in the hydrostat so oil flows out the top port of the
pump. Oil flow out of the top port goes to the wheel mo-
tors and turns them in the reverse direction.
Oil flowing out of the wheel motors returns to the bottom
port of the hydrostat and is continuously pumped out the
bottom port.
The charge circuit functions the same in reverse as it did
in the forward direction.
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