![background image](http://html1.mh-extra.com/html/takeuchi/tl150/tl150_workshop-manual_3333853218.webp)
IV-72
HYDRAULIC UNITS
PILOT VALVE
OPERATION
The pilot valve casing contains a vertical shaft hole
with a reducing valve incorporated into it. When
the handle is tilted, the push rod and spring seat
are pushed down changing the secondary pressure
spring
·
s pressure.
The casing also contains an inlet port for hydrau-
lic oil port P (primary pressure) and an outlet port,
port T (tank) and secondary pressure is taken from 4
ports, port 1, port 2, port 3 and port 4, on the bottom
of the vertical shaft hole.
When the Handle is in Neutral
In this case, the force of the secondary pressure set-
ting spring, which determines the pilot valve
·
s out-
put pressure (secondary pressure), is not transmitted
to the spool. Therefore, the spool is pushed up by
the return spring and is in the output port C position
shown above, with oil not flowing between port P
and the output port C but flowing between the T port
and output port C.
When the Handle is Tilted
When the handle (1) is tilted and the push rod is
pushed, the spool moves downward and port P and
port A are joined. The oil in the pilot valve pump
flows out to port A, generating pressure.
a. When the pressure in port A is the same as the
set force of the spring (set pressure), there is a
balance between the hydraulic pressure and the
spring force.
b. When the pressure in port A is greater than the set
pressure, port A and port P close and port A and
port T open.
c. When the pressure at port A is lower than the set
pressure, port A and port P open and port A and
port T close.
In this way, the secondary pressure is kept constant.
Summary of Contents for TL150
Page 1: ...TL150 Track Loader BOOK No CT7E901 WORKSHOP MANUAL Serial No 21500004...
Page 4: ...0 4...
Page 5: ...I 1 I GENERAL...
Page 18: ...I 14 GENERAL...
Page 19: ...II 1 II SPECIFICATIONS...
Page 44: ...III 1 III MACHINE CONFIGURATION...
Page 94: ...III 51 MACHINE CONFIGURATION ELECTRICAL SYSTEM ELECTRICAL SYSTEM ELECTRICAL WIRING DIAGRAM...
Page 122: ...III 79...
Page 146: ...MACHINE CONFIGURATION III 103...
Page 147: ...IV 1 IV HYDRAULIC UNITS...
Page 152: ...IV 6 HYDRAULIC UNITS HST PUMP 1 Plug 2 Plug 3 Plug 4 Screw 5 Seal Nut 6 Plug Pump Assembly 4 4...
Page 189: ...IV 43 HYDRAULIC UNITS GEAR PUMP INSPECTION AND ADJUSTMENT IV 36 38 TROUBLESHOOTING IV 39...
Page 230: ...IV 84 HYDRAULIC UNITS PILOT VALVE INSPECTION AND ADJUSTMENT IV 79 TROUBLESHOOTING IV 80...
Page 261: ...IV 115 HYDRAULIC UNITS TRAVEL MOTOR DISASSEMBLY AND ASSEMBLY Special tools...
Page 263: ...IV 117 HYDRAULIC UNITS TRAVEL MOTOR...
Page 282: ...IV 136 HYDRAULIC UNITS TRAVEL MOTOR...
Page 283: ...V 1 V TROUBLESHOOTING...