Hydraulic Flow Diagrams (5610-D); Traction Circuit (5610-D) - Toro Reelmaster 5410 Series Service Manual

Hydraulic Flow Diagrams (5610-D)

Traction Circuit (5610-D)

Forward Direction
Reverse Direction
Hydraulic System: Hydraulic Flow Diagrams (5610-D)
The hydraulic traction circuit consists of a variable displacement piston pump
(P5) connected in a closed loop, parallel circuit to 4 orbital roller vane wheel
motors. The traction pump input shaft is rotated by a driveshaft that is driven
from the engine flywheel.
The forward traction circuit pressure can be measured at the test port located in
the hydraulic tube that connects the front wheel motors. The reverse traction
circuit pressure can be measured at the test ports in the crosstrax manifold
(Figure 72).
Pressing the top of traction pedal, angles the traction pump swash plate to
create a flow of fluid. This fluid flow is directed to the wheel motors via hydraulic
hoses and tubes to drive the wheels in forward direction. The traction pump
flow is directed to the front wheel motors and then to the opposite rear wheel
motors to maximize the traction. To reduce the tire scuffing when turning, the
traction system pressure is equalized in the crosstrax manifold with an orifice
and a bi-directional relief valve. The bi-directional relief valve in the crosstrax
manifold allow rear wheel motors to over-run during tight turns. The forward
traction pressure is limited to 25,000 kPa (3,625 psi) by the forward traction relief
valve (R3) located in the traction pump.
The fluid flowing from the wheel motors returns to the variable displacement
pump and is continuously pumped through the traction circuit as long as the
traction pedal is pressed.
The angle of the swash plate determines pump flow and ultimately traction
speed. When the traction pedal is pressed a small amount, a small swash plate
rotation results in low pump output and lower traction speed. When the traction
pedal is pressed fully, the pump swash plate rotates fully to provide maximum
pump output and traction speed.
The gear pump section (P3) supplies fluid flow for the steering circuit and also
provides a constant supply of charge fluid to the closed loop traction circuit.
This charge fluid provides lubrication for traction circuit components and also
replenishes traction circuit fluid that is lost due to internal leakage in the traction
circuit.
The gear pump section (P3) takes its suction from the hydraulic reservoir. The
charge pump flow is directed to the low pressure side of the closed loop traction
circuit. Charge relief valve (R5) located in the traction pump limits the charge
relief pressure to 1,400 kPa (200 psi).
The piston pump is equipped with a case drain to allow internal leakage to be
removed from the pump. The case drain is connected to the gear pump inlet.
The piston pump (P5) includes a flushing valve that bleeds off a small amount of
hydraulic fluid for cooling of the closed loop traction circuit. The charge system
replenishes fluid that is bled from the traction circuit by the flushing valve.
The traction circuit operates essentially the same in reverse as it does in the
forward direction. However, in the reverse direction the rear wheel motors
are bypassed from the circuit to prevent rear wheel spin and improve steering
control. Pressing the bottom of the traction pedal, rotates the traction pump
swash plate to create a flow of fluid. The fluid flow is directed to the crosstrax
Page 6–32 Reelmaster ® 5410/5510/5610 Series
15216SL Rev C