3-15
GROUP 4 SINGLE OPERATION
When the right control lever is pulled back, the boom spools in the main control valve are moved to
the up position by the pilot oil pressure from the remote control valve.
The oil from the A1 and A2 pump flows into the main control valve and then goes to the large
chamber of boom cylinders. At the same time, the oil from the small chamber of boom cylinders
returns to the hydraulic oil tank through the boom 1 spool in the main control valve. When this
happens, the boom goes up. The excessive pressure in the boom cylinder head side is prevented
by relief valve. When the boom is up and the control lever is returned to neutral position, the circuit
for the holding pressure at the head side of the boom cylinder is closed by the boom holding valve.
This prevents the hydraulic drift of boom cylinder.
1. BOOM UP OPERATION
LEFT
Pd41
B2
A2
Pb1
A1
B1
Pa1
T1
V3
Pd2
Pc2
Pc1
P0
DR0
Pd1
Ai
B4
B5
A5
Pa5
Pb5
Pa4
Pb4
C5
D5
Pc41
Rs
DR4
P03
Patt
P02
Pn2
Pn1
Po5
Puo
P04
DR2
Pc3
Pb21
Pb20
Pa20
DR1
DR5
DR3
Pc40
Pd40
PS
PS
Pi1(Pump)
Pi2(Pump)
BUCKET
CYLINDER
BOOM
CYLINDER
A1
PUMP
A2
PUMP
PILOT
PUMP
HYDRAULIC TANK
Pd41
Pb3
Pc42
Pc40
Pc41
C6
D6
ARM
CYLINDER
DOZER
CYLINDER
TURNING
JOINT
TRAVEL MOTOR
SWING MOTOR
D2
C2
D1
C1
D4
C4
Pa21
Pa20
P04
Pc5
Pd5
Pd6
Pc6
TRAVEL
STRAIGHT
TRAVEL
RIGHT
TRAVEL
BOOM 1
SWING
BOOM 2
ARM 1
OPTION B
OPTION C
(DOZER)
ARM
BUCKET
ARM 2
REGEN
Pu
P1
P2
P3
Pd0
BOOM
HOLDING
VALVE
RELIEF
VALVE
140L3HC10
Summary of Contents for HX140L
Page 12: ...SECTION 1 GENERAL SECTION 1 GENERAL Group 1 Safety Hints 1 1 Group 2 Specifications 1 10...
Page 209: ...4 5 MEMORANDUM...
Page 694: ...8 68 125LCR8TM30 Turn casing 1 upside down and remove oil seal 3 using jig 29...
Page 734: ...8 108 Assemble plug 2 Plug NPT1 16 11 EA 17 21078TM68 21078TM69 21078TM70 21078TM71...
Page 756: ...8 130 Remove lock nut 22 and then boot 23 14 36078RL14 2507ARL10...