Toro Groundsmaster 5900 Series Service Manual page 132

PTO Mow Circuit Cutting Deck Blade Braking (continued)
Hydraulic System: Hydraulic Flow Diagrams
1.5 CID
PTO SWITCH OFF
LC1, RV AND LC2 SHIFTED
g287725
The inertia of the rotating cutting blades, however, effectively turns the deck
motor into a pump causing an increase in pressure as the flow from the motor
comes up against the closed logic cartridge (LC2). When this pressure builds
to approximately 41 bar (600 PSI), relief valve (RV) opens which allows a small
amount of hydraulic flow to return to tank through a manifold sensing line
45). This flow causes a pressure increase that shifts logic cartridge LC2 to once
again allow oil flow from the motor
below 41 bar (600 PSI), relief valve (RV) reseats and causes LC2 to close again
blocking return flow from the deck motor to further slow the cutting blades. This
action of the brake relief valve opening and the logic cartridge shifting occurs
several times in a very short time frame as the blades finally come to a stop.
Once the blades have stopped, logic cartridge LC2 remains in the unshifted
position to keep the deck motor from rotating.
M1
OR2 .025"
SQ
110 PSI RV
PRV
600 PSI
10 PSI
M2
LC2
OR1
.063"
LEFT DECK
V NOT ENERGIZED
Figure 46
(Figure 46). When return pressure drops
Page 5–32
G1
P1
PUMP
FLOW
10 PSI LC1
3000 PSI
P2
CD
RETURN
Groundsmaster ®
16227SL Rev B
(Figure
5900 & 5910