PC340LC (NLC) - 7 UEN00262-00 Structure, Function & Maintenance Standard
PC340LC (NLC) - 7 UEN00262-00 Structure, Function & Maintenance Standard
PC340LC (NLC) - 7 UEN00262-00 Structure, Function & Maintenance Standard
PC340LC-7
PC340NLC-7
PC340-7 1
UEN00269-00 10 Structure, function and maintenance standard
2 PC340-7
10 Structure, function and maintenance standard UEN00269-00
Specifications
Radiator: Aluminum wave type, 4th row
Oil cooler: CF40-1
PC340-7 3
UEN00269-00
© 2006 KOMATSU
All Rights Reserved
Printed in Belgium 05-06 (00)
4
UEN00270-00
PC340LC-7
PC340NLC-7
PC340-7 1
UEN00270-00 10 Structure, function and maintenance standard
Power train 1
Power train 1
1. Idler
2. Center swivel joint
3. Control valve
4. Final drive
5. Travel motor (HMV160ADT-2)
6. Engine (SAA6D114E)
7. Hydraulic pump (HPV125+125)
8. Travel speed solenoid valve
9. Swing brake solenoid valve
10. Swing machinery
11. Swing motor (HMF230ABE-5)
12. Swing circle
2 PC340-7
10 Structure, function and maintenance standard UEN00270-00
PC340-7 3
UEN00270-00 10 Structure, function and maintenance standard
Final drive 1
Specifications
Reduction ratio: –((11+97)/11) x ((19+97)/19) = –59.943
4 PC340-7
10 Structure, function and maintenance standard UEN00270-00
Unit: mm
No. Check Item Criteria Remedy
Backlash between No. 1 sun gear Standard clearance Clearance limit
15 and No.1 planetary gear
0.12 – 0.44 0.9
Backlash between No. 1 planetary
16 gear and ring gear
0.18 – 0.62 1.2
PC340-7 5
UEN00270-00 10 Structure, function and maintenance standard
Sprocket 1
Unit: mm
No. Check Item Criteria Remedy
Standard size Repair limit
1 Wear of tooth tip
336.5 324.5
Build-up welding
2 Thickness of tooth root 20 14
for rebuilding or
3 Width of tooth 87 84 replace
Repair limit: 6 (measure with the full-size drawing of sprocket tooth
4 Wear of tooth shape shape)
6 PC340-7
10 Structure, function and maintenance standard UEN00270-00
a The above drawing is reduced to 62%. Enlarge it to 160% to return it to the full scale and make a copy
on an OHP sheet.
PC340-7 7
UEN00270-00 10 Structure, function and maintenance standard
Swing machinery 1
8 PC340-7
10 Structure, function and maintenance standard UEN00270-00
Specifications
Reduction ratio: ((19+68)/19) x ((24+68)/24) = 17.553
Unit: mm
No. Check Item Criteria Remedy
Backlash between swing motor Standard clearance Clearance limit
15 shaft and No. 1 sun gear
0.18 – 0.28 –
Backlash between No. 1 sun gear
16 and No.1 planetary gear
0.15 – 0.51 1.00
PC340-7 9
UEN00270-00 10 Structure, function and maintenance standard
Swing circle 1
Specifications
Reduction ratio: –90/13 = –6.923
Amount of grease: 33 l (G2-LI)
Unit: mm
No. Check Item Criteria Remedy
Axial clearance of bearing (when Standard clearance Clearance limit
4 mounted on chassis) Replace
0.5 – 1.6 3.2
10 PC340-7
10 Structure, function and maintenance standard UEN00270-00
PC340-7 11
UEN00270-00
© 2006 KOMATSU
All Rights Reserved
Printed in Belgium 05-06 (00)
12
UEN00271-00
PC340LC-7
PC340NLC-7
PC340-7 1
UEN00271-00 10 Structure, function and maintenance standard
2 PC340-7
10 Structure, function and maintenance standard UEN00271-00
Standard shoe
Models
PC340LC-7 PC340NLC-7
Item
Shoe width (triple shoe) (mm) 700 600
Link pitch (mm) 216 216
No. of shoes (one side) 48 48
Unit: mm
No. Check Item Criteria Remedy
Standard size Tolerance Repair limit
Track +2
Vertical width of idler 123 127
9 guide frame –1
Idler sup- Build-up welding
120 ±0.5 118 for rebuilding or
port
Track +3 replace
266 271
Horizontal width of idler frame –1
10 guide Idler sup-
261 — 259
port
Standard size Rapair limit
Free length x Installation Installation Installation
Free length
11 Recoil spring O.D. length load load Replace
173.3 kN 138.56 kN
794 x 241 648 —
{17,680 kg} {14,140 kg}
PC340-7 3
UEN00271-00 10 Structure, function and maintenance standard
Idler 1
4 PC340-7
10 Structure, function and maintenance standard UEN00271-00
Unit: mm
No. Check Item Criteria Remedy
Standard size Repair limit
1 Outside diameter of protrusion
635 —
2 Outside diameter of tread 590 578
Build-up welding for
3 Difference of tread 22.5 28.5 rebuilding or
4 Thickness of tread — — replace
PC340-7 5
UEN00271-00 10 Structure, function and maintenance standard
Carrier roller 1
Unit: mm
No. Check Item Criteria Remedy
Standard size Repair limit
1 Outside diameter of flange
179 —
2 Outside diameter of tread 152 138
3 Width of tread 50.3 —
4 Thickness of tread 32 25
5 Width of flange 19 —
Standard Tolerance Standard Clearance
Clearance between shaft and bush- size Shaft Hole clearance limit Replace
6 ing –0.250 +0.074 0.250 –
54 —
–0.280 +0.040 0.354
Standard Tolerance Standard Interference
Interference between roller and size Shaft Hole interference limit
7 bushing +0.117 +0.030 0.057 –
61 —
+0.087 +0.040 0.117
Standard clearance Clearance limit
8 Axial clearance of roller
0.5 – 0.7 —
6 PC340-7
10 Structure, function and maintenance standard UEN00271-00
Track roller 1
Unit: mm
No. Check Item Criteria Remedy
Standard size Repair limit
1 Outside diameter of outer flange
216 —
Outside diameter of inner flange
2 (Double flange)
210 —
PC340-7 7
UEN00271-00 10 Structure, function and maintenance standard
Track shoe 1
Unit: mm
No. Check Item Criteria Remedy
Standard size Repair limit
1 Link pitch
216.3 219.3 Reverse or
Standard size Reverse replace
2 Outside diameter of bushing
66.9 61.9
3 Thickness of bushing metal 10.8 5.8 Adjust or replace
Standard size Repair limit
4 Link height
116 107
Repair or replace
Thickness of link metal (bushing
5 press-fitting portion)
30.7 21.7
8 PC340-7
10 Structure, function and maintenance standard UEN00271-00
Unit: mm
No. Check Item Criteria Remedy
6 178.4
7 Shoe bolt pitch 140.4 Replace
8 76.2
Inside
9 width
102
Overall
10 Link width
47.8 Repair or replace
Tread
11 width
42.6
Tolerance
Standard size Standard clearance
Clearance between regular pin and Shaft Hole
23 bushing
+0.235 +0.915
44.6 0.180 – 0.830 Adjust or replace
+0.085 +0.415
Tolerance Standard interfer-
Standard size
24 Interference between master pin Shaft Hole ence
(*) and link +0.03 –0.188
44.6 0.188 – 0.280
+0.03 –0.250
Tolerance
Standard size Standard clearance
25 Clearance between master pin and Shaft Hole
(*) bushing +0.050 +0.915
44.3 0.365 – 0.965
–0.050 +0.415
PC340-7 9
UEN00271-00 10 Structure, function and maintenance standard
Unit: mm
No. Check Item Criteria Remedy
Standard size Repair limit
1 Height 36 24
(*) 30 18
2 Thickness 11
32
3
(*) 29
Length of base
26
4
(*) 24 Build-up welding
24 for rebuilding or
5 replace
(*) 22
18
6 Length at tip
(*) 16
18
7
(*) 22
Standard size Repair limit
8 Thickness 47 35
(*) 41 29
10 PC340-7
10 Structure, function and maintenance standard UEN00271-00
PC340-7 11
UEN00271-00
© 2006 KOMATSU
All Rights Reserved
Printed in Belgium 05-06 (00)
12
UEN00272-00
PC340LC-7
PC340NLC-7
PC340-7 1
UEN00272-00 10 Structure, function and maintenance standard
1. Bucket cylinder
2. Arm cylinder
3. Boom cylinder
4. Swing motor
5. Control valve
6. Oil cooler
7. Hydraulic filter
8. Hydraulic pump
9. L.H. travel motor
10. Hydraulic tank
11. Multi-pattern selector valve
12. L.H. PPC valve
13. Work equipment lock lever (electric type)
14. Center swivel joint
15. R.H. PPC valve
16. Travel PPC valve
17. Attachment circuit selector valve
18. Hydraulic drift prevention valve
19. Accumulator
20. Solenoid valve assembly
20A. PPC lock solenoid
20B. Travel junction solenoid
20C. Pump merge-divider solenoid
20D. Travel speed solenoid
20E. Swing brake solenoid
20F. Machine push-up solenoid
20G. 2-stage relief solenoid
2 PC340-7
10 Structure, function and maintenance standard UEN00272-00
PC340-7 3
UEN00272-00 10 Structure, function and maintenance standard
4 PC340-7
10 Structure, function and maintenance standard UEN00272-00
PC340-7 5
UEN00272-00 10 Structure, function and maintenance standard
Hydraulic pump 1
Type: HPV125+125
6 PC340-7
10 Structure, function and maintenance standard UEN00272-00
Outline
q This pump consists of 2 variable capacity
swash plate piston pumps, PC valve, LS valve,
EPC valve and variable volume valve.
1. Front pump
2. Rear pump
3. LS valve
4. PC valve
5. LS-EPC valve
6. PC-EPC valve
7. Variable volume valve
PC340-7 7
UEN00272-00 10 Structure, function and maintenance standard
8 PC340-7
10 Structure, function and maintenance standard UEN00272-00
Function
q The pump converts the engine rotation trans-
mitted to the shaft to oil pressure and delivers
pressurized oil corresponding to the load.
q It is possible to change the discharge amount
by changing the swash plate angle.
Structure
q Cylinder block (7) is supported to shaft (1) by q Piston (6) carries out relative movement in the
spline (14). axial direction inside each cylinder chamber of
q Shaft (1) is supported by front and rear bear- cylinder block (7).
ings (15). q Cylinder block (7) seals the pressurized oil to
q Tip of piston (6) is shaped as a concave ball valve plate (8) and carries out relative rotation.
and shoe (5) is caulked to it to form one unit. q This surface is designed so that the oil pres-
q Piston (6) and shoe (5) constitute the spherical sure balance is maintained at a suitable level.
bearing. q The oil inside each cylinder chamber of cylin-
q Rocker cam (4) has flat surface (A), and shoe der block (7) is suctioned and discharged
(5) is always pressed against this surface while through valve plate (8).
sliding in a circular movement.
q Rocker cam (4) conducts high pressure oil to
cylinder surface (B) with cradle (2), which is
secured to the case, and forms a static pres-
sure bearing when it slides.
PC340-7 9
UEN00272-00 10 Structure, function and maintenance standard
Operation of pump
q Cylinder block (7) rotates together with shaft q As center line (X) of rocker cam (4) matches
(1), and shoe (5) slides on flat surface (A). the axial direction of cylinder block (7) (swash
q When this happens, rocker cam (4) moves plate angle (a) = 0), the difference between
along cylindrical surface (B), so angle (a) volumes (E) and (F) inside cylinder block (7)
between center line (X) of rocker cam (4) and becomes 0.
th e axi al d ir ec ti on o f cy lin de r bl oc k (7 ) q Suction and discharge of pressurized oil is not
changes. carried out in this state. Namely pumping
q (a) is named the swash plate angle. action is not performed. (Actually, however, the
swash plate angle is not set to 0)
10 PC340-7
10 Structure, function and maintenance standard UEN00272-00
PC340-7 11
UEN00272-00 10 Structure, function and maintenance standard
1. LS valve
12 PC340-7
10 Structure, function and maintenance standard UEN00272-00
Operation
q The LS valve is a 3-way selector valve, with q Spool (6) is pushed to the right, and port (C)
pressure (PLS) (LS pressure) from the outlet and port (D) will be connected.
port of the control valve brought to spring q Pump pressure (PP) is conducted to the larger
chamber (B), and main pump discharge pres- diameter end from the port (K).
sure (PP) brought to port (H) of sleeve (8). q The same pump pressure (PP) is conducted to
q Magnitude of the force resulting from this LS the smaller diameter end from the port (J).
pressure (PLS), force of spring (4) and the q According to the difference in the areas on
pump delivery pressure (self pressure) (PP) servo piston (12), the pressure moves in such
determine the position of spool (6). that the swash plate angle may be minimized.
q However, magnitude of the output pressure
(PSIG) (called the LS selector pressure) of the
EPC valve for the LS valve entering port (G)
also changes the position of spool (6). (Setting
force of the spring is changed)
q Before the engine is started, servo piston (12) is
pushed to the right. (See the figure)
q If the control lever is at the neutral position
when the engine is started, LS pressure (PLS)
will be set to 0 MPa {0 kg/cm 2}. (It is intercon-
nected to the drain circuit via the control valve
spool)
PC340-7 13
UEN00272-00 10 Structure, function and maintenance standard
q When the difference between the main pump q If the output pressure of the EPC valve for the
pressure (PP) and LS pressure (PLS), in other LS valve enters port (G), rightward force is
words , LS d iffe renti al p re ssur e ( EPLS) generated on piston (7).
becomes smaller (for example, when the area q If piston (7) is pushed to the right, setting force
of opening of the control valve becomes larger of spring (4) is weakened, changing the LS dif-
and pump pressure PP drops), spool (6) is ferential pressure (EPLS) [Difference between
pushed to the left by the combined force of LS oil pressures (PLS) and (PP)] when ports (D)
pressure (PLS) and the force of spring (4). and (E) of spool (6) are connected.
q When spool (6) moves, port (D) and port (E)
are interconnected and connected to the PC
valve.
q The PC valve is connected to the drain port, so
the pressure across circuits (D) and (K)
becomes drain pressure (PT). (The operation
of the PC valve is explained later.)
q The pressure at the large diameter end of
servo piston (12) becomes drain pressure
(PT), and pump pressure (PP) enters port (J)
at the small diameter end, so servo piston (12)
is pushed to the left side. Therefore, the swash
plate is moved in the direction to make the dis-
charge amount larger.
14 PC340-7
10 Structure, function and maintenance standard UEN00272-00
PC340-7 15
UEN00272-00 10 Structure, function and maintenance standard
q Let us take the area receiving the pressure at q Force of spring (4) is adjusted in such that the
the large diameter end of the piston as (A1), position of the balanced stop of this spool (6)
the area receiving the pressure at the small may be determined when (PP) – (PLS) = 2.45
diameter end as (A0), and the pressure flowing MPa {25 kg/cm 2} on the front pump side and
into the large diameter end of the piston as (PP) – (PLS) = 2.55 MPa {26 kg/cm2} on the
(PEN). rear pump side at the median of the specified
q If the main pump pressure (PP) of the LS valve value.
and the combined force of spring (4) and LS q If (PSIG) [Output pressure of LS-EPC valve, 0
pressure (PLS) are balanced, and the relation- to 2.9 MPa {0 to 30 kg/cm2}] is input to port (G),
ship is (A0) x (PP) = (A1) x (PEN), servo piston the position of the balanced stop is changed.
(12) will stop in that position. The front pump side will be moved in the range
q And the swash plate of the pump will be held in of (PP) –(PLS) = 2.45 to 0.98 MPa {25 to 0 kg/
an intermediate position. [Spool (6) will be cm 2} and the rear pump will be moved in the
stopped at a position where the distance of the range of (PP) – (PLS) = 2.55 to 1.08 MPa {26
opening from port (D) to port (E) and the dis- to 11 kg/cm 2} in proportion to (PSIG) pressure.
tance from port (C) to port (D) is almost the
same.]
q At this point, the relationship between the pres-
sure receiving areas across servo piston (12)
is (A0) : (A1) = 3 : 5, so the pressure applied
across the piston when it is balanced becomes
(PP) : (PEN) C 5 : 3.
16 PC340-7
10 Structure, function and maintenance standard UEN00272-00
2. PC valve
Function
q When the pump discharge pressure (PP1) q If the engine speed goes below the specified
(self-pressure) and (PP2) (other pump pres- value because of increased load, the controller
sure) are high, the PC valve controls the pump sends a command current to PC-EPC valve
so that the volume of oil beyond the discharge solenoid in order to reduce the slope angle in
pressure-based specific flowrate may not be proportion to reduction in the engine speed.
conducted however you may increase the con-
trol valve stroke. Namely it is intended at con-
trolling the horse power for the pumps so that it
may not exceed the engine hose power.
q If the pump discharge pressure increases due
to increased load during operation, this valve
decreases the pump delivery.
q And if the pump delivery pressure goes low, it
increases the pump delivery.
q In this case, relation between the mean dis-
charge pressure of the front and rear pumps
[(PP1) + (PP2)]/2 and the pump delivery (Q)
will becomes as shown in the diagram if the
relation is represented as the parameter the
current value (X) to be given to PC-EPC valve
solenoid.
q The controller continues counting the actual
engine speed.
q If the engine speed is slowed down due to
increased load, the controller reduces the
pump delivery to recover the speed.
PC340-7 17
UEN00272-00 10 Structure, function and maintenance standard
Operation
(1) When the load on the actuator is small and pump discharge pressures (PP1) and (PP2) are low
18 PC340-7
10 Structure, function and maintenance standard UEN00272-00
PC340-7 19
UEN00272-00 10 Structure, function and maintenance standard
Action of spring
q Load of springs (4) and (6) on the PC valve is q When pump pressures (PP1) and (PP2) are
determined by the swash plate position. small, spool (3) will be positioned in the left
q As servo piston (9) moves to right, spring (6) is side.
retracted. q Port (C) and (D) are connected, and the pres-
q If the servo piston moves further, it will be con- sure entering the LS valve becomes drain
tacted again seat (5) and spring (6) will be pressure (PT).
fixed. q If port (E) and port (G) of the LS valve are con-
q After that, spring (4) alone will operate. nected, the pressure entering the large diame-
q The spring load is changed by servo piston (9) ter end of the piston from port (J) becomes
as it extends or compresses springs (4) and drain pressure (PT), and servo piston (9)
(6). moves to the left side.
q If the command current (X) to PC-EPC valve q The pump delivery will be set to the increasing
solenoid (1) changes, so does the force push- trend.
ing piston (2). q Accompanied with move of servo piston (9),
q Spring load of springs (4) and (6) is also springs (4) and (6) will be expanded and the
affected by the command current (X) to PC- spring force becomes weaker.
EPC valve solenoid. q As the spring force is weakened, spool (3)
q Port (C) of the PC valve is connected to port moves to the right, the connecting between
(E) of the LS valve. port (C) and port (D) is shut off and the pump
q Self pressure (PP1) enters port (B) and the discharge pressure ports (B) and (C) are con-
small diameter end of servo piston (9), and nected.
other pump pressure (PP2) enters port (A).
20 PC340-7
10 Structure, function and maintenance standard UEN00272-00
PC340-7 21
UEN00272-00 10 Structure, function and maintenance standard
(2) When load on actuator is large and pump discharge pressure is high
Outline Operation
q When the load is large and pump discharge q When port (E) and port (G) of the LS valve are
pressures (PP1) and (PP2) are high, the force connected, this pressure from port (J) enters
pushing spool (3) to the right becomes larger the large diameter end of servo piston (9),
and spool (3) will be moved to the position stopping servo piston (9).
shown in above figure. q If main pump pressure (PP2) increases further
q Part of the pressure to be conducted from port and spool (3) moves further to the right, main
(C) to LS valve flows from port (B) to port (C) pump pressure (PP1) flows to port (C) and acts
and (D) via LS valve. At the end this flow, level to make the pump delivery the minimum.
of this pressure becomes approximately half of q When servo piston (9) moves to the right,
the main pump pressure (PP2). springs (4) and (6) are compressed and push
back spool (3).
q When spool (3) moves to the left, the opening
of port (C) and port (D) becomes larger.
q As a result, the pressure on port (C) (= J) is
decreased and the rightward move servo pis-
ton (9) is stopped.
q The position in which servo piston (9) stops at
this time is further to the right than the position
when pump pressures (PP1) and (PP2) are
low.
22 PC340-7
10 Structure, function and maintenance standard UEN00272-00
PC340-7 23
UEN00272-00 10 Structure, function and maintenance standard
2) As the emergency pump drive switch is turned on due to failure on the pump controller
q If there is a failure in the pump controller, the q Since the pressure on the small diameter end
emergency pump drive switch is turned on to of the piston large, servo piston (9) moves in
hand the control to the resistor side. the direction to make the discharge amount
q In this case, the power is directly supplied from larger.
the battery. The current, however, is too large
as is, so the resistor is set in between to con-
trol the current flowing to PC-EPC valve sole-
noid (1).
q The current becomes constant, so the force
pushing piston (2) is also constant.
q If the main pump pressures (PP1) and (PP2)
are low, the combined force of the pump pres-
sure and the PC-EPC valve solenoid (1) is
weaker than the spring set force, so spool (3)
is balanced at a position to the left.
q At this point, port (C) is connected to the drain
pressure of port (D), and the large diameter
end of the piston of servo piston (9) also
becomes the drain pressure (PT) through the
LS valve.
24 PC340-7
10 Structure, function and maintenance standard UEN00272-00
q If the emergency pump drive switch is turned q The curve resulting when the emergency pump
on In the same way as in above, the command drive switch is ON is situated further to the left
current (X) sent to PC-EPC valve solenoid (1) (B) than when the pump controller is normal
becomes constant. (A).
q For this reason, the force of piston (2) pushing
spool (3) is constant.
q If main pump pressures (PP1) and (PP2)
increase, spool (3) moves further to the right
than when the main pump load is light, and is
balanced at the position in the diagram above.
q In this case, the pressure from port (B) flows to
port (C), so servo piston (9) moves to the right
(smaller pump delivery) and stops at a position
to the further to the right then when the load on
the pump is light.
q When the emergency pump drive switch is
turned on, too, the pump pressure (PP) and
pump delivery (Q) have a relationship as
shown with the curve in the figure correspond-
ing to the current sent to the PC-EPC valve
solenoid through the resistor.
PC340-7 25
UEN00272-00 10 Structure, function and maintenance standard
3. LS(PC)-EPC Valve
C: To LS(PC) valve
P: From self pressure reducing valve
T: To tank
1. Connector
2. Coil
3. Body
4. Spring
5. Spool
6. Rod
7. Plunger
26 PC340-7
10 Structure, function and maintenance standard UEN00272-00
Function Operation
q The EPC valve consists of the proportional
solenoid portion and the hydraulic valve por- 1) When signal current is 0 (coil is deener-
tion. gized)
q When it receives signal current (i) from the q When there is no signal current flowing from
controller, it generates the EPC output pres- the controller to coil (2), coil (2) is deenergized.
sure in proportion to the size of the signal, and q Spool (5) is pushed to the left by spring (4).
outputs it to the LS (PC) valve. q Port (P) closes and the pressurized oil from the
self pressure reducing valve does not flow to
the LS (PC) valve.
q The pressurized oil from the LS (PC) valve is
drained to the tank via port (C) and port (T).
PC340-7 27
UEN00272-00 10 Structure, function and maintenance standard
2) When signal current is very small (coil is 3) When signal current is maximum (coil is
energized) energized)
q When a very small signal current flows to coil q As the signal current flows to coil (2), coil (2) is
(2), coil (2) is energized, and a propulsion force energized.
is generated on the right side of plunger (7). q When this happens, the signal current is at its
q Rod (6) pushes spool (5) to the right, and pres- maximum, so the propulsion force of plunger
surized oil flows from port (P) to port (C). (7) is also at its maximum.
q Pressures on port (C) increases and the force q Spool (5) is pushed toward right side by rod
to act on spool (5) surface and the spring load (6).
on spring (4) become larger than the propul- q The maximum volume of pressurized oil is
sion force of plunger (7). conducted from port (P) to port (C), increasing
q Spool (5) is pushed to the left, and port (P) is the circuit pressure across EPC valve and LS
shut off from port (C). (PC) valve to the maximum level.
q Port (C) and port (T) are connected. q Since port (T) is closed, pressurized oil does
q Spool (5) moves up and down so that the pro- not flow to the tank.
pulsion force of plunger (7) may be balance
with pressure of port (C) + spring load of spring
(4).
q The circuit pressure between the EPC valve
and the LS (PC) valve is controlled in propor-
tion to the size of the signal current.
28 PC340-7
10 Structure, function and maintenance standard UEN00272-00
Function
q The variable volume valve stabilizes the EPC
valve's output pressure.
Operation
q Output pressure from EPC valve is conducted
to port (C) and as the result propulsion force of
piston (3) is increased by the load of spring (4).
q Piston (3) is pushed to the left, and volume of
port (C) is increased.
q The propulsion force of piston (3) becomes
smaller than the load of spring (4).
q Piston (3) is pushed toward right, and volume
of port (C) is decreased.
PC340-7 29
UEN00272-00
© 2006 KOMATSU
All Rights Reserved
Printed in Belgium 05-06 (00)
30
UEN00273-00
PC340LC-7
PC340NLC-7
PC340-7 1
UEN00273-00 10 Structure, function and maintenance standard
2 PC340-7
10 Structure, function and maintenance standard UEN00273-00
General view
PC340-7 3
UEN00273-00 10 Structure, function and maintenance standard
Sectional view
(1/5)
4 PC340-7
10 Structure, function and maintenance standard UEN00273-00
Unit: mm
PC340-7 5
UEN00273-00 10 Structure, function and maintenance standard
(2/5)
6 PC340-7
10 Structure, function and maintenance standard UEN00273-00
Unit: mm
PC340-7 7
UEN00273-00 10 Structure, function and maintenance standard
(3/5)
8 PC340-7
10 Structure, function and maintenance standard UEN00273-00
1. Unload valve
2. Safety valve (Boom raise)
3. Main relief valve
4. Lift check valve
Arm valve
5. LS shuttle valve
6. Pressure compensation valve (IN)
7. Spool
8. Safety-suction valve (IN)
9. Regeneration circuit check valve
10. Safety-suction valve (OUT)
11. Pressure compensation valve (OUT)
Swing valve
18. LS select valve
19. Pressure compensation valve (R.H.)
20. Spool
21. Pressure compensation valve (L.H.)
Unit: mm
PC340-7 9
UEN00273-00 10 Structure, function and maintenance standard
(4/5)
10 PC340-7
10 Structure, function and maintenance standard UEN00273-00
1. Return spring
2. Merge-divide valve (for LS)
3. Valve (Sequence valve)
4. Spring (Sequence valve)
5. Merge-divide valve (Main)
6. Return spring
Boom valve
7. Drift prevention valve
8. LS shuttle valve
9. Pressure compensation valve (Lower)
10. Spool
11. 2-stage safety-suction valve (Lower)
12. Regeneration circuit check valve
13. Suction valve (Raise)
14. Pressure compensation valve (Raise)
Bucket valve
23. LS shuttle valve
24. Pressure compensation valve (Curl)
25. Spool
26. Safety-suction valve (Curl)
27. Safety-suction valve (Dump)
28. Pressure compensation valve (Dump)
Unit: mm
PC340-7 11
UEN00273-00 10 Structure, function and maintenance standard
(5/5)
12 PC340-7
10 Structure, function and maintenance standard UEN00273-00
Service valve 1
8. LS shuttle valve
9. Pressure compensation valve
10. Spool
11. 2-stage safety-suction valve
12. Safety-suction valve
Service valve 2
13. LS shuttle valve
14. Pressure compensation valve
15. Spool
16. Safety-suction valve
17. Unload valve
18. Main relief valve
19. LS bypass plug
PC340-7 13
UEN00273-00 10 Structure, function and maintenance standard
CLSS 1
Outline of CLSS
Features Configuration
CLSS stands for Closed center Load sensing Sys- q CLSS is configured with variable capacity pis-
tem, which has the following characteristics: ton pumps, control valves, and respective
actuators.
q Fine control not influenced by load q The hydraulic pump is configured with pump
q Controllability enabling digging even with fine body, PC valve and LS valve.
control
q Ease of compound operation ensured by flow
divider function using area of opening of spool
during compound operations
q Energy saving using variable pump control
14 PC340-7
10 Structure, function and maintenance standard UEN00273-00
Basic principle
1. Pump swash plate angle control
q The pump swash plate angle (pump delivery) q The pump swash plate angle shifts toward the
is controlled so that LS differential pressure maximum position if LS differential pressure
(EPLS) (the difference between pump pres- (EPLS) is lower than the set pressure of the
sure PP and control valve outlet port LS pres- LS valve (when the actuator load pressure is
sure PLS) (load pressure of actuator) is high).
constant. q If it becomes higher than the set pressure
q [LS differential pressure (EPLS) = Pump dis- (when the actuator load pressure is low), the
charge pressure (PP) – S pressure (PLS)] pump swash plate angle shifts toward the mini-
mum position.
PC340-7 15
UEN00273-00 10 Structure, function and maintenance standard
16 PC340-7
10 Structure, function and maintenance standard UEN00273-00
3. System diagram
PC340-7 17
UEN00273-00 10 Structure, function and maintenance standard
18 PC340-7
10 Structure, function and maintenance standard UEN00273-00
PC340-7 19
UEN00273-00 10 Structure, function and maintenance standard
Unload valve
1. When the unload valve is actuating
Function Operation
q Drains an oil discharge for the portion of the q Pressure of pump circuit (3) is received by the
minimum pump swash plate angle while all end of valve (2).
control valves are in the holding. q Since the control valve is in neutral position,
q The pump pressure will correspond to a set pressure of LS circuit (1) is 0 MPa{0 kg/cm2}.
load of spring (5) inside the valve (this pres- q Pressurized oil of pump circuit (3) stops at
sure will be P1). valve (2), and the pressure rises as no relief is
q Since LS pressure is drained from the LS available.
bypass valve, LS pressure C tank pressure C 0 q When this pressure becomes larger than the
MPa{0 kg/cm2}. force of spring (5), valve (2) moves to the left.
q Ports (b) and (c) are interconnected and the
pump pressure flows to tank circuit (4).
q The pressurized oil of LS circuit (1) passes
from orifice (a) via port (c) and is drained to the
tank circuit (4).
q When actuated, LS pressure C tank pressure.
q Since the pump discharge pressure - LS circuit
pressure during unloading is larger than the
pump LS control pressure, the signal is output
to minimize the pump swash plate angle.
20 PC340-7
10 Structure, function and maintenance standard UEN00273-00
PC340-7 21
UEN00273-00 10 Structure, function and maintenance standard
Introduction of LS pressure
1. Hydraulic pump
2. Main spool
3. Pressure compensation valve
4. Valve
5. Check valve
6. LS circuit
7. LS shuttle valve
Function
q Introduces the upstream pressure (down-
stream pressure of the spool meter-in) of pres-
sure compensation valve (3) and leads to LS
shuttle valve (7) as the LS pressure.
q Connected to actuator port (B) via valve (4),
and makes LS pressure C actuator load pres-
sure.
q Inlet pore (a) inside main spool (2) has a small
diameter concurrently serving as a throttle.
Operation
q When main spool (2) is operated, the pump
pressure enters port (c) via inlet pore (a) and is
led to the LS circuit.
q When the pump pressures rises to reach the
load pressure of port (B), check valve (5)
opens.
22 PC340-7
10 Structure, function and maintenance standard UEN00273-00
LS bypass valve
1. Hydraulic pump
2. Main spool
3. Pressure compensation valve
4. LS shuttle valve
5. LS bypass valve
6. LS circuit
Function
q Releases the residual pressure in LS pressure
circuit (6) from orifices (a) and (b).
q Slows down the rising rate of LS pressure to
prevent a sudden change of hydraulic pres-
sure.
q Bypass flow from LS bypass valve (5) causes
a pressure loss to be generated due to the cir-
cuit resistance between throttle (c) of main
spool (2) and LS shuttle valve (4).
q Effective LS differential pressure drops to
improve a dynamic stability of the actuator.
PC340-7 23
UEN00273-00 10 Structure, function and maintenance standard
(If the load pressure is higher than other work equipment during a combined operation)
24 PC340-7
10 Structure, function and maintenance standard UEN00273-00
2. When compensated
(If the load pressure is lower than other work equipment during a combined operation)
Function
q The pressure compensation valve closes
under LS pressure of port (D), and the spool
meter-in downstream pressure of port (B)
becomes equivalent to the maximum pressure
of other work equipment.
q Since the spool meter-in upstream pressure of
port (A) is the pump pressure, the spool meter-
in differential pressure [upstream pressure port
(A) pressure] - downstream pressure [port (B)
pressure] becomes equivalent to all the spools
in operation.
q Pump flow is divided according to the ratio of
the meter-in opening area.
Operation
q Spring chamber (E) is interconnected to port
(D).
q Piston (4) and valve (2) operate in the closing
direction (to the right) under the LS circuit pres-
sure from other work equipment of port (F).
q Valve upstream pressure (= spool meter-in
downstream pressure) of port (B) is controlled
with LS pressure.
PC340-7 25
UEN00273-00 10 Structure, function and maintenance standard
Function
q The state of division changes according to the
area ratio of pressure compensation portion
(A1) and (A2). Area ratio = (A2)/(A1)
q If area ratio = 1 : the spool meter-in down-
stream pressure will be equal to the maximum
load pressure, and the pressure will be divided
according to the opening area ratio.
q If area ratio = 1 or over : the spool meter-in
downstream pressure will be greater than the
maximum load pressure, and the pressure will
be divided smaller than the opening area ratio.
q If area ratio = 1 or under : the spool meter-in
downstream pressure will be smaller than the
maximum load pressure, and the pressure will
be divided greater than the opening area ratio.
26 PC340-7
10 Structure, function and maintenance standard UEN00273-00
1. Hydraulic pump
2. Valve
3. Pressure compensation valve inner shuttle
valve
4. Piston
Function
q Shuttle valve (3) is pushed to the right by port
(A) pressure and cuts off interconnection
between ports (A) and (C).
q Holding pressure at port (A) is led to the spring
chamber (B) to push piston (4) to the left so
that piston (4) and valve (2) will not be sepa-
rated.
PC340-7 27
UEN00273-00 10 Structure, function and maintenance standard
Outline
q Since no holding pressure is generated at port
(A) of the travel circuit, a pressure compensa-
tion valve without shuttle valve (3) is adopted.
28 PC340-7
10 Structure, function and maintenance standard UEN00273-00
1. Hydraulic pump
2. Boom spool
3. Pressure compensation valve
4. Safety-suction valve
5. Suction valve
6. Check valve
7. LS shuttle valve
Function Operation
q Provides the regeneration circuit from the cyl- q If the cylinder head pressure is lower than the
inder bottom to the cylinder head when the bottom pressure, pressurized oil (A) from the
boom is lowered and increases flow to the cyl- cylinder bottom flows to drain circuit (B) from
inder bottom. the notch of boom spool (2).
q On the other hand, remaining oil flows to
regeneration circuit (C), opens check valve (6)
and flows to the cylinder head via circuit (D).
q Flow from regeneration circuit (C) and pump
(1) merges in circuit (E).
PC340-7 29
UEN00273-00 10 Structure, function and maintenance standard
2. If the cylinder head pressure is higher than the bottom pressure (digging work, etc.)
Function
q Check valve (6) provided to regeneration cir-
cuit (C) closes to shut off the flow from the cyl-
inder bottom to the head.
30 PC340-7
10 Structure, function and maintenance standard UEN00273-00
1. Hydraulic pump
2. Arm spool
3. Pressure compensation valve
4. Safety-suction valve
5. Suction valve
6. Check valve
7. LS shuttle valve
Function Operation
q During arm digging, regeneration circuit pro- q If the cylinder head pressure is lower than the
vided from the cylinder head to the bottom bottom pressure, pressurized oil (A) from the
increases the cylinder speed as the cylinder cylinder bottom flows to drain circuit (B) from
flow involves the pump delivery plus regener- the notch of arm spool (2).
ated flow. q On the other hand, remaining oil flows to
regeneration circuit (C), opens check valve (6)
and flows to the cylinder head via circuit (D).
q Flow from regeneration circuit (C) and pump
(1) merges in circuit (E).
PC340-7 31
UEN00273-00 10 Structure, function and maintenance standard
Function
q Check valve (6) provided to regeneration cir-
cuit (C) closes to shut off the flow from the cyl-
inder bottom to the head.
32 PC340-7
10 Structure, function and maintenance standard UEN00273-00
Merge-divider valve 1
1. When flows from the pumps merge [if pilot pressure (PS) is OFF]
Function Operation
q Merges pressurized oil (P1) and (P2) dis- q Since pilot pressure (PS) is OFF, output pres-
charged from the two pumps or divides (to sure from PPC valve is 0 kg/cm2.
respective control valve group). q Main spool (1) is pressed to the right by spring
q Merges and divides LS circuit pressure. (2) and ports (E) and (F) are interconnected.
q Merges pressurized oil (P1) and (P2) dis-
charged from the two pumps at ports (E) and
(F) and sends to necessary control valve.
q Since pilot pressure (PS) is OFF for LS spool
(3), it is pressed to the right by spring (4), and
ports (A) - (D) and ports (B) - (C) are intercon-
nected.
q Forwards LS pressure led from respective con-
trol valve spools to LS circuits (5), (6), (7) and
(8) to all the pressure compensation valves.
PC340-7 33
UEN00273-00 10 Structure, function and maintenance standard
2. When flows from the pumps are divided [if pilot pressure (PS) is ON]
Operation
q Pilot pressure (PS) turns ON, and output pres-
sure from the PPC valve shifts main spool (1)
to the left, and ports (E) and (F) are divided.
q Pressurized oil discharged from the two pumps
are sent to respective control valves.
34 PC340-7
10 Structure, function and maintenance standard UEN00273-00
LS select valve
Function Operation
q Prevents high LS pressure from the swinging 1. If pilot pressure (BP) is OFF
from entering the LS circuit of work valves q Since pilot pressure (BP) is OFF, piston (3) is
while the swinging and work equipment are in pressed to the left by spring (2).
combined operation. q When swing-operated, swing LS pressure (P1)
q Prevents high pressure generated during enters port (A) after passing swing spool (5).
swing drive and improves operability of work q Valve (1) is pressed to the left and ports (A)
equipment. and (B) are interconnected.
q Swing LS pressure (P1) flows to LS shuttle
valve (8).
1. Valve
2. Spring
3. Piston
4. Piston
5. Swing spool
6. L.H. travel spool
7. Arm spool
8. LS shuttle valve
9. LS circuit
PC340-7 35
UEN00273-00 10 Structure, function and maintenance standard
Function
q Reduces the discharge pressure of the main
pump and supplies it as control pressure for
the solenoid valves, EPC valves, etc.
Operation
1. While engine is stopped
q Poppet (11) is pressed by spring (12) against
the seat and port (PR) is not connected to
(TS).
q Valve (14) is pressed by spring (13) against the
left side and port (P2) is connected to (TS).
q Valve (7) is pressed by spring (8) against the
left side and port (P2) is closed to (A2).
36 PC340-7
10 Structure, function and maintenance standard UEN00273-00
2. During neutral and when load pressure (P2) 3. When load pressure (P2) is high
is low q Load pressure (A2) increases with the opera-
a When load pressure (A2) is lower than self tion of digging, etc., and the pump discharge
pressure reducing valve output pressure (PR) increases accordingly.
q Pressure (P2) increases to [( d area x P2 pres-
q Valve (7) is pressed to the closing direction of sure) = force of spring (8) + ( d area x PR pres-
circuit between ports (P2) and (A2) by spring sure)]., and valve (7) moves to the right to the
(8) and under pressure (PR) (which is 0 MPa stroke end.
{0 kg/cm2}). q As a result, opening between ports (P2) and
q When pressurized oil flows in from port (P2), a (A2) increases, and the pass resistance
balance is reached due to [( d area x P2 pres- reduces, reducing the engine horsepower loss.
sure) = force of spring (8) + ( d area x PR pres- q When pressure (PR) rises above the set pres-
sure)]. sure, poppet (11) opens.
q Adjusts valve (7) opening to keep pressure q Pressurized oil flows from port (PR) to orifice
(P2) at a constant level over pressure (PR). (a) in spool (14), then flows to seal drain port
q When pressure (PR) rises above the set pres- (TS) from poppet (11) opening.
sure, poppet (11) opens. q Differential pressure is generated before and
q Pressurized oil flows from port (PR) to orifice after orifice (a) in spool (14) and then spool
(a) in spool (14), then flows to seal drain port (14) moves to close the pass between ports
(TS) from poppet (11) opening. (P2) and (PR).
q Differential pressure is generated before and q Pressure (P2) is reduced by the opening at this
after orifice (a) in spool (14) and then spool time and adjusted to a constant pressure (the
(14) moves to close the pass between ports set pressure) and supplied as pressure (PR).
(P2) and (PR).
q Pressure (P2) is reduced by the opening at this
time and adjusted to a constant pressure (the
set pressure) and supplied as pressure (PR).
PC340-7 37
UEN00273-00 10 Structure, function and maintenance standard
38 PC340-7
10 Structure, function and maintenance standard UEN00273-00
Function Operation
q This valve connects the L.H. and R.H. travel q Pilot pressure from the travel junction solenoid
circuits via travel junction valve so that the valve contracts spring (1), and travel junction
hydraulic oil will be supplied evenly to both spool (2) moves to the left to the stroke end.
travel motors to improve machine's straight q Junction circuit between port (PTL) (L.H. travel
travel performance. circuit) and port (PTR) (R.H. travel circuit) is
q When the machine is steered, outside pilot closed.
pressure (PST) closes the travel junction valve
to improve steering performance.
PC340-7 39
UEN00273-00 10 Structure, function and maintenance standard
Operation
q If pilot pressure (PST) from the solenoid valve q If the oil flow rates to the L.H. and R.H. travel
is 0, travel junction spool (2) is pressed by the motors become different from each other, the
force of spring (1) against the right side and oil flows through the route between port (PTL),
the pass between ports (PTL) and (PTR) is travel junction spool (2), and port (PTR) so that
open. the oil flow rates to both motors will be equal-
ized again.
40 PC340-7
10 Structure, function and maintenance standard UEN00273-00
Function Operation
q Regulates flow to each cylinder by controlling q The oil in stroke regulation signal chamber (a)
the stroke of each spool of the boom, arm, and is drained through orifices (5) and (6) of pis-
bucket using the pilot pressure of travel PPC tons (3) and (4) in the travel spring case and
valve while climbing a steep grade, raising the the travel PPC valve.
boom, digging with arm, dumping, bucket-dig- q When operated for boom raising (or arm dig-
ging or operating dump. ging, dumping, bucket digging, dumping),
q When controlling the stroke of the boom, arm spool (1) moves to the left until it makes con-
and/or bucket, pilot pressure of travel PPC tact with the end face of spring casing (2) (st0).
valve passes through the circuit inside the con-
trol valves to actuate the system.
PC340-7 41
UEN00273-00 10 Structure, function and maintenance standard
2. When traveling
Operation
q If the right travel lever is set in the reverse (or q Maximum stroke of the spool is limited to (st1)
forward) direction, pilot pressure from the PPC for the amount of movement (st2) of piston (8)
valve presses spool (7) to the left (or right). to the right.
q Spool (7) pushes piston (3) to close orifice (5)
and shut off stroke regulation signal chamber
(a) and the drain circuit of the travel PPC
valve.
q At this time, the right travel reverse (or forward)
lever is set, PPC pressure is applied through
orifice (6) of piston (4) to the left end of piston
(8) to push piston (8) to the right.
q When operated for boom raising (or arm IN,
OUT, bucket CURL, DUMP), spool (1) moves
to the left.
42 PC340-7
10 Structure, function and maintenance standard UEN00273-00
Function
q When arm OUT, large volume of oil returns
from the cylinder bottom.
q Reduces this pressure loss.
Operation
q When the arm OUT is operated, pilot spool (1) increases by the sum of the pressure receiving
is pushed under the pilot pressure from the force of pressure receiving portion[ d1 area
PPC valve. (S1)] on the chamber (b) side of valve (2) and
q Pressurized oil in chamber (b) inside the valve the spring force.
is drained via orifice (c). q Or ( d2 pressure receiving force > d1 pres-
q Pressurized oil of the arm bottom side flows to sure receiving force + spring force)
orifice (a) o chamber (b) o orifice (c) o drain q Valve (2) is pressed to the left and pressurized
(T), and the pressure in chamber (b) lowers. oil is led from port (A) to (B).
q If the pressure of chamber (b) drops lower than q From port (B), pressurized oil is drained
that of port (A), pressure receiving force of the directly to the tank.
pressure receiving portion [ d2 area (S2) (seat
di a me t er ar e a) ] on t he si d e o f p o rt (A )
PC340-7 43
UEN00273-00 10 Structure, function and maintenance standard
Operation
q Returning the lever to neutral reduces the pilot
pressure from the PPC valve to 0 kg/cm2.
q The pressurized oil that has flowed and been
drained through orifice (a) in valve (2) is closed
by pilot piston (1).
q The holding pressure on the arm bottom side
works on the difference between areas (S2)
and (S1) of valve (2) to the right.
q Valve (2) is closed by the total of this force and
the force of spring (3), so ports (A) and (B) are
shut off.
44 PC340-7
10 Structure, function and maintenance standard UEN00273-00
PC340-7 45
UEN00273-00 10 Structure, function and maintenance standard
1. Spring
2. Poppet
Function Operation
q Set pressure of the relief valve is in two stages. q The set pressure of relief valve is determined
q When power is needed, pilot pressure (P) is by spring (1) installed load. (1st stage)
turned ON and the set pressure becomes q Respective setting is not required for both the
higher. 1st and 2nd stages. Setting the 1st stage com-
pletes the setting of the 2nd stage.
46 PC340-7
10 Structure, function and maintenance standard UEN00273-00
PC340-7 47
UEN00273-00 10 Structure, function and maintenance standard
1. Spring
2. Piston
3. Spring
4. Holder
Function Operation
q Enables to provide the safety valve set pres- q The safety set pressure is determined by
sure in two stages, and make the low-pressure spring (1) installed load.
setting smaller.
q Enables to relieve a load without lever opera- 1. If pilot pressure is OFF (high-pressure set-
tion if high load is applied to the cylinder. ting)
q Improves work efficiency and reduces machine q Since pilot pressure (P) is OFF, piston (2) is
body vibration. pressed to the left by spring (3). [Spring (1)
installed load < spring (3) installed load]
q Spring (1) installed load becomes maximum
and the set pressure rises.
q Passage (B) is interconnected to the drain cir-
cuit via passage (C) and chamber (D).
48 PC340-7
10 Structure, function and maintenance standard UEN00273-00
PC340-7 49
UEN00273-00 10 Structure, function and maintenance standard
50 PC340-7
10 Structure, function and maintenance standard UEN00273-00
Operation when jointly operated with a high- q If the difference between the pump discharge
load work equipment (such as the boom rais- pressure (P) and cylinder port pressure (B) is
ing) larger than the force of spring (5), poppet (4) is
pressed to the right.
q Both of the pump discharge pressure (P) and
q Pump discharge pressure (P) flows to orifice
LS pressures are determined by other equip-
(a) and chamber (g) and is interconnected to
ment's pressure, while cylinder port pressure
cylinder port via passages (b) and (c).
causes the attachment to operate.
q Differential pressure is generated between the
q If the difference between the pump discharge
upstream and downstream of orifice (a), which
pressure (P) and cylinder pressure is smaller
reduces the pressure force in chamber (g).
than the force of spring (5), the balance of
q Force that presses valve (1) to the left is
forces applying to valve (1) may be expressed
reduced.
with the following equation:
q A state is reached where the area ratio has
become smaller.
P x A1 = P x A2 + LS(A2 – 1) + F
q Valve (1) moves to the right, and the flow
increases from the pump to the cylinder.
A1: Area of d1
A2: Area of d2
F: Force of spring
P: Pump discharge oil pressure
PC340-7 51
UEN00273-00 10 Structure, function and maintenance standard
Unit: mm
52 PC340-7
10 Structure, function and maintenance standard UEN00273-00
Function
q When a breaker is installed, the return oil from
the breaker does not pass through the main
valve, but returns directly to the hydraulic tank.
q When other attachments (crusher, etc.) are
installed, the attachment and the main valve
are interconnected.
Operation
1. When attachment other than breaker is 2. When breaker is installed
installed q Pilot pressure from the attachment circuit
q Spool (1) is pressed to the left by the force of selector solenoid valve contracts spring (2),
spring (2). and spool (1) moves to the right to the stroke
q Ports (ATT) and (V) are interconnected and end.
ports (ATT) and (T) are shut off. Attachment is q Ports (ATT) and (V) are shut off and ports
thus interconnected to the control valve. (ATT) and (T) are interconnected.
q Pressurized oil returning from the breaker
returns directly to the hydraulic tank via port (T)
without passing through the control valve.
PC340-7 53
UEN00273-00 10 Structure, function and maintenance standard
54 PC340-7
10 Structure, function and maintenance standard UEN00273-00
1. Pilot spool
2. Spool (1st stage spool)
3. Spring (2nd stage spool)
4. Safety valve
5. Check valve
6. Spring
Unit: mm
PC340-7 55
UEN00273-00 10 Structure, function and maintenance standard
Function
q Prevents the pressurized oil from reversing
from the work equipment cylinder and the latter
from a su dde n d rop if th e pipi ng bur sts
between the control valve and the work equip-
ment cylinder.
Operation
1. When the work equipment lever is in neutral
56 PC340-7
10 Structure, function and maintenance standard UEN00273-00
2. When pressurized oil flows from the main valve to the cylinder
PC340-7 57
UEN00273-00 10 Structure, function and maintenance standard
3. When returning pressurized oil to the main valve from the work equipment cylinder
58 PC340-7
10 Structure, function and maintenance standard UEN00273-00
PC340-7 59
UEN00273-00
© 2006 KOMATSU
All Rights Reserved
Printed in Belgium 05-06 (00)
60
UEN00274-00
PC340LC-7
PC340NLC-7
PC340-7 1
UEN00274-00 10 Structure, function and maintenance standard
2 PC340-7
10 Structure, function and maintenance standard UEN00274-00
PC340-7 3
UEN00274-00 10 Structure, function and maintenance standard
PPC valve 1
Work equipment and swing PPC valve
4 PC340-7
10 Structure, function and maintenance standard UEN00274-00
1. Spool 7. Joint
2. Metering spring 8. Plate
3. Centering spring 9. Retainer
4. Piston 10. Body
5. Disc 11. Filter
6. Nut (for lever connection)
Unit: mm
PC340-7 5
UEN00274-00 10 Structure, function and maintenance standard
Operation
1. When in neutral q The relationship of the position of spool (1) and
q Ports (A) and (B) of the control valve and ports body (10) [fine control hole (f) is in the middle
(P1) and (P2) of the PPC valve are connected between drain chamber (D) and pump pres-
to drain chamber (D) via fine control hole (f) in sure chamber (PP)] does not change until
spool (1). retainer (9) contacts spool (1).
q Metering spring (2) contracts in proportion to
the stroke of the control lever.
q Pressure at port (P1) also rises in proportion to
the stroke of the control lever.
q In this way, the control valve spool moves to a
position where the pressure of chamber (A)
(same as pressure at port (P1)) and the force
of the return spring of the control valve spool
are balanced.
6 PC340-7
10 Structure, function and maintenance standard UEN00274-00
PC340-7 7
UEN00274-00 10 Structure, function and maintenance standard
8 PC340-7
10 Structure, function and maintenance standard UEN00274-00
PC340-7 9
UEN00274-00 10 Structure, function and maintenance standard
10 PC340-7
10 Structure, function and maintenance standard UEN00274-00
1. Plate
2. Body
3. Piston
4. Collar
5. Centering spring
6. Metering spring
7. Valve
8. Dumper
9. Steering signal spool
10. Steering signal spool spring
Unit: mm
PC340-7 11
UEN00274-00 10 Structure, function and maintenance standard
12 PC340-7
10 Structure, function and maintenance standard UEN00274-00
3) During fine control q Therefore, the pilot pressure oil from the self
(When control lever is returned) pressure reducing valve passes through fine
q When lever (5) starts to be returned, spool (1) control hole (f) and flows to chamber (A) from
is pushed up by the force of centering spring port (P1) to push the control valve spool.
(3) and pressure at port (P1). q The oil returning from chamber (B) passes
q Because of this, fine control hole (f) is con- from port (P2) through fine control hole (f') and
nected to drain chamber (D), and the pressur- flows to drain chamber (D).
ized oil at port (P1) is released.
q If the pressure of port (P1) is lowered exces-
sively, spool (1) is pushed down by metering
spring (2).
q Fine control hole (f) is shut off from drain
chamber (D), and it is almost simultaneously
interconnected to pump pressure chamber
(PP).
q Pump pressure is supplied until the pressure at
port (P1) recovers to the level equivalent to the
lever position.
q When the spool of the control valve returns,
the oil in drain chamber (D) flows in from fine
control hole (f') in the valve on the side that is
not working. The oil passes through port (P2)
and enters chamber (B) to replenish the cham-
ber with pressurized oil.
Steering signal
q If the operation quantities of both levers are dif-
ferent from each other as in the steering opera-
ti o n, t h e h i gh e r o n e o f t h e P P C o u t pu t
pressures of both sides is output as the steer-
ing signal.
q Any signal is not output from port (P6) while
the machine is travelling straight (forward or
reverse) or in neutral.
4) At full stroke
q Accordingly, whether the machine is being
q Lever (5) pushes down piston (4), and retainer
steered is judged by the signal of port (P6).
(9) pushes down spool (1).
q Fine control hole (f) is shut off from drain
chamber (D), and is interconnected to pump
pressure chamber (PP).
PC340-7 13
UEN00274-00 10 Structure, function and maintenance standard
Operation
1) When in neutral
14 PC340-7
10 Structure, function and maintenance standard UEN00274-00
PC340-7 15
UEN00274-00 10 Structure, function and maintenance standard
a The Illustration shows the circuit for left forward (slow) and right forward (fast) operation.
q If the operation quantities of both levers are dif- q Port (P4) pressure of the L.H. or R.H. PPC
ferent from each other as in the steering opera- valves, whichever having a higher output pres-
tion (if the difference of the pilot pressure sure, is output to port (P6) as the steering sig-
between both sides is higher than a certain nal.
level), the pilot pressure is output as the steer-
ing signal.
q The pressure in left spring chamber (k) of
steering signal spool (j) is (P2).
q The pressure in right spring chamber (l) is
(P4).
q When the pressure state reaches [(P4 - P2) x
(Spool section) > Spring set load], the spool is
switched to the direction of the arrow.
16 PC340-7
10 Structure, function and maintenance standard UEN00274-00
4) When counter-rotated
a The illustration shows the circuit for travelling left reverse and right forward.
PC340-7 17
UEN00274-00 10 Structure, function and maintenance standard
a For the details of operation, see the paragraph of “Work equipment swing PPC valve.“
18 PC340-7
10 Structure, function and maintenance standard UEN00274-00
Unit: mm
PC340-7 19
UEN00274-00 10 Structure, function and maintenance standard
Solenoid valve 1
PPC lock, travel junction, merge-divider, travel speed, swing brake, machine push-up and 2-stage
relief solenoid valves
20 PC340-7
10 Structure, function and maintenance standard UEN00274-00
1. Connector 4. Spool
2. Moving core 5. Block
3. Coil 6. Spring
Operation
When solenoid is deenergized When solenoid is energized
q Since the signal current does not flow from the q The signal current flows from the controller to
controller, solenoid (3) is deenergized. For this solenoid (3), and the latter is energized.
reason, spool (4) is pushed to the left by spring Accordingly, spool (4) is pressed against to the
(6). By this operation, the pass from port (P) to right side. By this operation, the pressurized oil
port (A) is closed and the pressurized oil from from the main pump flows through port (P) and
the main pump does not flow into the actuator. spool (4) to port (A), then flows into the actua-
At this time, the oil from the actuator is drained tor. At the same time, port (T) closes and stops
through ports (A) and (T) into the tank. the oil from flowing to the tank.
PC340-7 21
UEN00274-00 10 Structure, function and maintenance standard
PPC accumulator 1
1. Gas plug
2. Shell
3. Poppet
4. Holder
5. Bladder
6. Oil port
Specifications
Gas capacity: 300 cc (for PPC)
22 PC340-7
10 Structure, function and maintenance standard UEN00274-00
For breaker
PC340-7 23
UEN00274-00 10 Structure, function and maintenance standard
Unit: mm
No. Check item Criteria Remedy
Clearance between rotor and Standard size Standard clearance Clearance limit
6 shaft
Replace
80 — —
24 PC340-7
10 Structure, function and maintenance standard UEN00274-00
Travel motor 1
Type: HMV160ADT-3
PC340-7 25
UEN00274-00 10 Structure, function and maintenance standard
26 PC340-7
10 Structure, function and maintenance standard UEN00274-00
1. Output shaft
2. Motor case
3. Rocker cam
4. Piston
5. Cylinder block
6. Valve plate
7. End cover
8. Slow return valve
9. Brake spring
10. Brake piston
11. Plate
12. Disc
13. Regulator piston
14. Check valve
15. Counter balance valve
16. Safety valve
17. Ball
18. Regulator valve
19. Spring
Unit: mm
No. Check item Criteria Remedy
Standard size Repair limit
Free length x Installation Installed Installed
Free length
20 Spool return spring Outside diameter length load load
427 N 341 N
58.43 x 30.0 42.0 —
{43.5 kg} {34.8 kg} If damaged or
1.27 N 0.98 N deformed, replace
21 Check valve spring 33.0 x 13.8 23.0
{0.13 kg}
—
{0.10 kg} spring.
Regulator piston 221 N 177 N
22 spring 61.1 x 23.2 43.9
{22.5 kg}
—
{18.0 kg}
Regulator valve 98.1 N 78.5 N
23 spring 29.6 x 9.0 26.0
{10.0 kg}
—
{8.0 kg}
PC340-7 27
UEN00274-00 10 Structure, function and maintenance standard
Operation of motor
1) At slow speed (motor swash plate angle at maximum)
q As the solenoid valve is deenergized, the pilot q The combined force of the piston propulsion
pressurized oil from the self pressure reducing forces works as the moment of inclining rocker
valve does not flow to port (P). cam (3) toward the maximum swash plate
q Regulator valve (21) is pushed to the right by angle.
spring (22). q The pressurized oil at regulator piston (13)
q Pressurized oil being conducted from the con- passes through orifice (c) of regulator valve
trol valve to end cover (7) by pressing slow (21) and is drained to the motor case.
return valve (8) is shut off by regulator valve q Rocker cam (3) is inclined in the maximum
(21). swash plate angle direction. The motor capac-
q Fulcrum (a) of rocker cam (3) is eccentric to ity becomes maximum, turning on the low
the working point (b) of the combined force of speed travel.
the propulsion force of cylinder (5).
28 PC340-7
10 Structure, function and maintenance standard UEN00274-00
PC340-7 29
UEN00274-00 10 Structure, function and maintenance standard
30 PC340-7
10 Structure, function and maintenance standard UEN00274-00
PC340-7 31
UEN00274-00 10 Structure, function and maintenance standard
32 PC340-7
10 Structure, function and maintenance standard UEN00274-00
PC340-7 33
UEN00274-00 10 Structure, function and maintenance standard
2. Safety valve
(bidirectional 2-stage set safety valve)
Bidirectional action
1) When pressure in chamber (MB) has
become high (when rotating clockwise)
q As long as the machine travel is stopped (or it
is travelling downhill), the check valve of coun-
terbalance valve closes chamber (MB) of the
outlet port circuit.
q The motor tries to continue rotation resorting to
inertial force, thus pressure on the outlet port
(MB) is increased.
34 PC340-7
10 Structure, function and maintenance standard UEN00274-00
2) When pressure in chamber (MA) has Operation of mechanism for varying set pres-
become high (when rotating counterclock- sure
wise) 1) When starting travel (high-pressure setting)
q As long as the machine travel is stopped (or it q As the travel lever is operated, the pressurized
is travelling downhill), the check valve of coun- oil from the pump moves spool (19) toward
terbalance valve closes chamber (MA) of the right.
outlet port circuit. q Above opens the pilot circuit to the safety
q The motor tries to continue rotation resorting to valve, conducting the pressurized oil to cham-
inertial force, thus pressure on the outlet port ber (J) via chamber (G) and passage (H).
(MA) is increased. q Piston (3) is pushed rightward, spring (2) is
compressed and the set load is increased.
q High pressure is turned on the safety valve,
providing a large tractional force to the valve.
PC340-7 35
UEN00274-00 10 Structure, function and maintenance standard
36 PC340-7
10 Structure, function and maintenance standard UEN00274-00
Swing motor 1
Type: KMF230ABE-5
PC340-7 37
UEN00274-00 10 Structure, function and maintenance standard
38 PC340-7
10 Structure, function and maintenance standard UEN00274-00
1. Brake spring
2. Drive shaft
3. Spacer
4. Case
5. Disc
6. Plate
7. Brake piston
8. Housing
9. Piston
10. Cylinder block
11. Valve plate
12. Center shaft
13. Center spring
14. Check valve
15. Check valve spring
16. Shuttle valve
17. Shuttle valve spring
Unit: mm
No. Check item Criteria Remedy
Standard size Repair limit
Free length x Installed Installed Installed
Free length
18 Check valve spring Outside diameter length load load If damaged or
6.96 N 5.59 N deformed, replace
66.5 x 25.6 45.0 — spring.
{0.71 kg} {0.57 kg}
7.45 N 5.98 N
19 Shuttle valve spring 24.5 x 11.6 14.5
{0.76 kg}
—
{0.61 kg}
PC340-7 39
UEN00274-00 10 Structure, function and maintenance standard
Operation Operation
q As the swing holding brake is deenergized, the q As the swing brake solenoid valve is ener-
pressurized oil from the self pressure reducing gized, the valve is switched.
valve is shut off. q The pressurized oil from the self pressure
q Port (B) is connected to tank circuit (T). reducing valve is conducted brake chamber (a)
q Brake piston (7) is pushed down by brake via port (B).
spring (1). q After entering chamber (a), the pressurized oil
q Disc (5) and plate (6) are pushed together, and compresses brake spring (1) and pushes
the brake is applied. brake piston (7) up.
q Disc (5) is separated from plate (6), releasing
the brake.
40 PC340-7
10 Structure, function and maintenance standard UEN00274-00
PC340-7 41
UEN00274-00 10 Structure, function and maintenance standard
42 PC340-7
10 Structure, function and maintenance standard UEN00274-00
1. Valve body
2. Spool (MA side)
3. Spring (MA side)
4. Plug (MA side)
5. Spool (MB side)
6. Spring (MB side)
7. Plug (MB side)
PC340-7 43
UEN00274-00 10 Structure, function and maintenance standard
44 PC340-7
10 Structure, function and maintenance standard UEN00274-00
PC340-7 45
UEN00274-00 10 Structure, function and maintenance standard
Hydraulic cylinder 1
Boom cylinder
Arm cylinder
46 PC340-7
10 Structure, function and maintenance standard UEN00274-00
Bucket cylinder
Unit: mm
No. Check item Criteria Remedy
Standard Tolerance Standard Clearance
Cylinder
size Shaft Hole clearance limit
-0.036 +0.035 0.041 –
Boom 100 0.412
Clearance between -0.091 +0.005 0.126
1 piston rod and bushing
Replace bushing
-0.036 +0.261 0.083 –
Arm 110 0.412
-0.091 +0.047 0.352
-0.036 +0.261 0.083 –
Bucket * 110 0.447
-0.091 +0.047 0.352
-0.036 +0.190 0.106 –
Boom 100 —
-0.090 +0.070 0.261
Clearance between
-0.036 +0.190 0.106 –
2 piston rod support Arm 100
-0.090 +0.070 0.280
—
shaft and bushing
-0.036 +0.190 0.106 –
Bucket * 90 —
-0.090 +0.070 0.280 Replace pin or
-0.036 +0.190 0.0106 – bushing
Boom 90 —
-0.090 +0.070 0.280
Clearance between
-0.036 +0.190 0.106 –
3 cylinder bottom support Arm 100
-0.090 +0.070 0.280
—
shaft and bushing
-0.036 +0.190 0.106 –
Bucket * 90 —
-0.090 +0.070 0.280
PC340-7 47
UEN00274-00
© 2006 KOMATSU
All Rights Reserved
Printed in Belgium 05-06 (00)
48
UEN00275-00
PC340LC-7
PC340NLC-7
PC340-7 1
UEN00275-00 10 Structure, function and maintenance standard
Work equipment 1
Work equipment 1
2 PC340-7
10 Structure, function and maintenance standard UEN00275-00
Unit: mm
No. Check item Criteria Remedy
Standard Tolerance Standard Clearance
Clearance between pin connecting size clearance limit
Shaft Hole
1 boom and revolving frame and
bushing –0.036 +0.144 0.110 –
110 1.0
–0.090 +0.074 0.234
Clearance between pin connecting –0.036 +0.148 0.116 –
2 boom and arm and bushing 110
–0.090 +0.080 0.238
1.0
PC340-7 3
UEN00275-00 10 Structure, function and maintenance standard
Dimensions of components 1
1. Dimension of arm
4 PC340-7
10 Structure, function and maintenance standard UEN00275-00
Unit: mm
PC340-7
No. Measuring position Standard Tolerance
size Shaft Hole
–0.036 +0.1
1 – 100
–0.090 0
+1.5
Arm side 119.3
2 0
Cylinder head side 116 ±1.2
+0.5
Boom side 320
0
3
–0.3
Arm side 316
–0.8
–0.036 +0.1
4 – 110
–0.090 0
5 – 423.7 ±1
6 – 277.9 ±0.5
7 – 1037.4 ±1
8 – 2535 ±3
9 – 2986.4 ±1
10 – 476 ±1
11 – 731.0 ±0.2
12 – 728.0 ±0.5
13 – 513.6 –
14 – 1670 –
–0.036 +0.2
15 – 90
–0.090 0
16 – 345.0 ±0.5
–0.036 +0.2
17 – 90
–0.090 0
0
Arm itself 330
18 –0.5
When press fitting bushing 345 –
Min. 1870 ±2.5
19
Max. 3155 –
PC340-7 5
UEN00275-00 10 Structure, function and maintenance standard
2. Dimension of bucket
6 PC340-7
10 Structure, function and maintenance standard UEN00275-00
Unit: mm
PC340LC / NLC -7
No. Measuring position Standard
Tolerance
size
1 – 512.2 ±0.5
2 – 37.9 ±0.5
3 – 94°19' –
4 – 513.6 –
5 – 1658 –
6 – 193 –
7 – – –
8 – 50° –
+0.2
9 – 90
+0.0
+1
10 – 346
0
11 – 68 –
12 – 138 –
+0.5
13 – 525.5
–0.5
14 – 26 –
A – 165 –
15
B – 150 –
16 – 200 –
17 – 146.1 –
18 – 138.2 –
19 – R115 –
20 – R100 –
+2
21 – 370
0
22 – 60 –
PC340-7 7
UEN00275-00
© 2006 KOMATSU
All Rights Reserved
Printed in Belgium 05-06 (00)
8
UEN00276-00
PC340LC-7
PC340NLC-7
PC340-7 1
UEN00276-00 10 Structure, function and maintenance standard
2 PC340-7
10 Structure, function and maintenance standard UEN00276-00
PC340-7 3
UEN00276-00
© 2006 KOMATSU
All Rights Reserved
Printed in Belgium 05-06 (00)
4
UEN00277-00
PC340LC-7
PC340NLC-7
PC340-7 1
UEN00277-00 10 Structure, function and maintenance standard
Electrical system 1
Engine control 1
2 PC340-7
10 Structure, function and maintenance standard UEN00277-00
Operation of system
Starting engine Stopping engine
q When the starting switch is turned to the q When detecting that the starting switch is set to
START position, the starting signal flows to the the “STOP” position, the engine controller cuts
starting motor. Then, the starting motor turns to the fuel injection to stop the engine.
start the engine.
PC340-7 3
UEN00277-00 10 Structure, function and maintenance standard
Component
1. Knob 4. Ball
2. Dial 5. Potentiometer
3. Spring 6. Connector
Function
q A potentiometer is installed under the knob. As
the knob is turned, the potentiometer shaft is
turned.
q As the potentiometer shaft is turned, the resis-
tance of the variable resistor in potentiometer
(5) changes and a throttle signal is sent to the
engine controller.
q The hatched area in the graph shown at right is
the abnormality detection area.
4 PC340-7
10 Structure, function and maintenance standard UEN00277-00
PC340-7 5
UEN00277-00 10 Structure, function and maintenance standard
Engine controller
6 PC340-7
10 Structure, function and maintenance standard UEN00277-00
CN-CE01 CN-CE02
Input/ Input/
Pin No. Signal name Pin No. Signal name
output output
28 NC(*) – 13 NC(*) B
29 NC(*) – 14 NC(*) B
30 NC(*) – 15 NC(*) B
31 NC(*) D 16 NC(*) B
32 NC(*) C 17 NC(*) B
33 GND A 18 NC(*) B
34 NC(*) – 19 NC(*) B
35 NC(*) A 20 NC(*) E
36 NC(*) – 21 NC(*) A
37 NC(*) A 22 Fuel control dial (+5V) A
38 NC(*) C 23 Fuel control dial (–) C
39 Key switch (ACC) – 24 NC(*) B
40 Electrical intake air heater relay drive – 25 NC(*) B
41 NC(*) – 26 NC(*) B
42 Electrical intake air heater relay return C 27 NC(*) B
43 NC(*) – 28 NC(*) B
44 Boost pressure sensor B 29 NC(*) C
45 Injector #1 (+) D 30 NC(*) B
46 Injector #5 (+) D 31 NC(*) B
47 sensor GND C 32 NC(*) C
48 Ne sensor (–) C 33 GND C
49 NC(*) – 34 NC(*) C
50 NC(*) – 35 NC(*) B
51 Injector #2 (–) C 36 NC(*) B
52 Injector #3 (–) C 37 NC(*) C
53 Injector #1 (–) C 38 NC(*) D
54 Injector #2 (+) D 39 Key switch (ACC) A
55 Injector #3 (+) D 40 Electrical intake air heater relay drive D
56 Injector #4 (+) D 41 NC(*) D
57 Injector #6 (+) D 42 Electrical intake air heater relay return C
58 Injector #4 (–) C 43 NC(*) D
59 Injector #6 (–) C 44 NC(*) D
60 Injector #5 (–) C 45 NC(*) –
*: Never connect to NC or malfunctions or failures will 46 CAN(+) E
occur. 47 CAN(–) E
48 NC(*) D
CN-CE02 49 PWM OUTPUT D
Input/ 50 NC(*) D
Pin No. Signal name
output *: Never connect to NC or malfunctions or failures will
1 NC(*) B occur.
2 NC(*) B
3 NC(*) B CN-CE03
4 NC(*) B Input/
Pin No. Signal name
5 NC(*) B output
6 NC(*) B 1 GND C
7 NC(*) B 2 NC(*) C
8 NC(*) B Electric power supply (+24V con-
3 A
9 Fuel control dial (+) B stantly)
10 NC(*) B 4 NC(*) A
11 NC(*) B *: Never connect to NC or malfunctions or failures will
12 NC(*) B occur.
*: Never connect to NC or malfunctions or failures will
occur.
PC340-7 7
UEN00277-00 10 Structure, function and maintenance standard
1. Connector
2. Sensor
3. O-ring
1. Connector
2. Sensor
3. O-ring
8 PC340-7
10 Structure, function and maintenance standard UEN00277-00
Rotation sensor
1. Connector
2. Sensor
3. O-ring
1. Connector
2. Sensor
3. O-ring
PC340-7 9
UEN00277-00 10 Structure, function and maintenance standard
1. Connector
2. Tube
3. Sensor
4. O-ring
1. Connector
2. Bracket
3. Float
4. Switch
10 PC340-7
10 Structure, function and maintenance standard UEN00277-00
Control function
1
Auto-deceleration function
8
Attachment flow control and circuit selector function
(if equipped)
Self-diagnosis function
PC340-7 11
UEN00277-00 10 Structure, function and maintenance standard
12 PC340-7
10 Structure, function and maintenance standard UEN00277-00
PC340-7 13
UEN00277-00 10 Structure, function and maintenance standard
14 PC340-7
10 Structure, function and maintenance standard UEN00277-00
PC340-7 15
UEN00277-00 10 Structure, function and maintenance standard
B and L modes
16 PC340-7
10 Structure, function and maintenance standard UEN00277-00
2) Function to control pump during travel 3) Function to control when emergency pump
q Traveling the machine in E or B mode drive switch is turned on
leaves the working mode unchanged, but q Even if any abnormality occurs in the controller
raises the pump absorption torque and or sensor, setting emergency pump drive
engine speed (N) to values same as those switch (10) to the “ON” position activates the
in P mode. machine with an absorption torque approxi-
q If the machine travels in L mode, the work- mately equivalent to that in E mode.
ing mode and engine speed (N) do not In this case, a constant current flows from the
change, but the pump absorption torque is battery to the EPC valve for PC and therefore,
increased. the oil pressure is sensed by only the EPC
valve for PC.
PC340-7 17
UEN00277-00 10 Structure, function and maintenance standard
Function
q The machine is matched to various types of
work properly with the 2-stage relief function to
increase the digging force, etc.
18 PC340-7
10 Structure, function and maintenance standard UEN00277-00
2) Cut-off function
q This function increases PC-EPC current
(J) to reduce the flow rate in the relief
state, improving fuel consumption.
PC340-7 19
UEN00277-00 10 Structure, function and maintenance standard
Function
q The power maximizing function allows the
operator to increase power for a certain time
by operating the left knob switch.
q The machine push-up function allows the oper-
ator to increase the boom pushing force by
operating the machine push-up switch.
20 PC340-7
10 Structure, function and maintenance standard UEN00277-00
PC340-7 21
UEN00277-00 10 Structure, function and maintenance standard
4. Auto-deceleration function
Function
q The auto-deceleration function automatically
reduces the engine speed to its medium speed
range when the all control levers are set in
NEUTRAL while waiting for a dump truck or
work to reduce the fuel consumption and
noise.
q If any lever is operated, the engine speed
instantly returns to the speed set with the fuel
control dial.
Operation
When control levers are set in neutral
q If all the control levers are kept to NEUTRAL
for 4 sec. during operation at a engine speed
above a decelerator operation level (approxi-
mately 1,400 rpm), this function lowers the
engine speed to the deceleration operation
level (approximately 1,400 rpm) and keeps it
until you operate any lever.
When any control lever is operated
q If you operate any control lever while the
engine speed is kept at the deceleration opera-
tion level, the engine speed instantly rises to
the level set with the fuel control dial.
22 PC340-7
10 Structure, function and maintenance standard UEN00277-00
Function
q The engine automatic warm-up function
increases the engine speed to warm up the
engine if coolant temperature is too low after
the engine starts.
q The overheat prevention function reduces the
pump load when coolant or hydraulic oil tem-
perature is too high during operation to protect
the engine from overheating.
PC340-7 23
UEN00277-00 10 Structure, function and maintenance standard
1) Auto-warm-up function
q After the engine is started, if the engine coolant temperature is low, the engine speed is raised auto-
matically to warm up the engine.
24 PC340-7
10 Structure, function and maintenance standard UEN00277-00
PC340-7 25
UEN00277-00 10 Structure, function and maintenance standard
Function
The swing lock and swing holding brake function
are provided as a swing control function.
26 PC340-7
10 Structure, function and maintenance standard UEN00277-00
1) Swing lock and swing holding brake func- 2) Quick hydraulic oil warm-up function when
tion swing lock switch is turned on
q The swing lock function (manual) is used q If swing lock switch (4) is turned on, the
to lock machine from swinging at any posi- pump cut-off function is cancelled and the
tion. The swing holding brake function relief pressure rises from 34.8 MPa {355
(automatic) is used to prevent hydraulic kg/cm 2} to 37.2 MPa {380 kg/cm 2}. If the
drift after the machine stops swinging. work equipment is relieved under this con-
q Operation of swing lock switch and swing dition, the hydraulic oil temperature rises
lock/holding brake quickly and the warm-up time can be
shortened.
Lock Lock Func-
Operation
switch lamp tion
If swing lever is set in
neutral, swing brake
Swing operates in about 7 sec.
OFF OFF holding If swing lever is oper-
brake ated, brake is released
and machine can swing
freely.
Swing lock operates and
machine is locked from
swinging.
Swing
ON ON Even if swing lever is
lock
operated, swing lock is
not reset and machine
does not swing.
Swing
holding ON OFF
brake (when controller has (when controller is nor-
release trouble) maly)
switch
Swing lock
ON OFF ON OFF
switch
Swing
Swing lock Swing lock Swing lock
Swing holding
is turned is can- is turned
brake brake is
on. celed. on.
turned on.
PC340-7 27
UEN00277-00 10 Structure, function and maintenance standard
Function
q The machine is provided with a function that
ensures travel performance best fit to the type
of work and jobsite by controlling pumps during
travel or allowing operator to change travel
speed automatically or manually.
28 PC340-7
10 Structure, function and maintenance standard UEN00277-00
PC340-7 29
UEN00277-00 10 Structure, function and maintenance standard
Function
q This function is available only with the attach-
ment specification.
q The function acts as follows according to the
flow command and working mode from the
monitor.
1) It throttles the attachment PPC pressure
and controls the flow when the pedal is
depressed fully.
2) In B mode and the other modes, it
switches to attachment single acting (B) or
double acting (other modes).
30 PC340-7
10 Structure, function and maintenance standard UEN00277-00
PC340-7 31
UEN00277-00 10 Structure, function and maintenance standard
1. Plug
2. Switch
3. Connector
Specifications
Type of contacts: Normally open contacts
Operating (ON) pressure:
0.5 ± 0.1 MPa {5.0 ± 1.0 kg/cm2}
Resetting (OFF) pressure:
0.3 ± 0.05 MPa {3.0 ± 0.5 kg/cm2}
Function
q The junction block has 6 PPC oil pressure
switches.
q This sensor detects the operating condition of
each actuator by the PPC pressure and trans-
mit it to the pump controller.
32 PC340-7
10 Structure, function and maintenance standard UEN00277-00
1. Sensor
2. Connector
Operation
q The oil pressure is applied to the diaphragm of
the oil pressure sensor from the pressure
intake part, the diaphragm is deformed.
q The deformation in the diaphragm causes the
resistance of the gauge to change. This
causes a change in the output voltage, which
is transmitted to the amplifier (voltage ampli-
fier).
PC340-7 33
UEN00277-00 10 Structure, function and maintenance standard
1. Sensor
2. Connector
Operation
q The relationship between the pressure applied
to sensors (P) and output voltage (E) is shown
in the figure below.
34 PC340-7
10 Structure, function and maintenance standard UEN00277-00
4) Pump controller
PC340-7 35
UEN00277-00 10 Structure, function and maintenance standard
CN-CP01 CN-CP02
Input/ Input/
Pin No. Signal name Pin No. Signal name
output output
1 NC(*) Input 1 NC(*) output
2 R pump pressure sensor Input 2 Emergency swing parking switch Input
3 NC(*) Input 3 NC(*) Input
4 NC(*) – 4 232C_RXD Input
5 NC(*) Input 5 NC(*) Input
6 NC(*) Input 6 NC(*) Input
7 NC(*) Input 7 Machine select 4 (ATT) Input
8 F pump pressure sensor Input 8 Service circuit SOL signal output
9 NC(*) Input 9 NC(*) output
10 GND (SIG) – 10 NC(*) Input
11 Knob switch Input 11 NC(*) output
12 NC(*) Input 12 CAN_SH –
13 Bucket digging pressure sensor Input 13 Machine select 5 (ATT) Input
14 NC(*) Input 14 232C_TXD output
15 NC(*) Input 15 NC(*) Input
16 NC(*) output 16 Travel steering signal Input
17 Key switch (C-terminal) Input 17 Machine select 3 Input
18 NC(*) Input 18 NC(*) output
19 Arm digging pressure sensor Input 19 NC(*) output
20 NC(*) Input 20 NC(*) Input
21 NC(*) – Input/
21 NC(*)
22 POT-PWR output output
23 Key switch (ACC-terminal) Input Input/
22 CANO_L
24 NC(*) Input output
*: Never connect to NC or malfunctions or failures will Input/
23 NC(*)
occur. output
24 FWE_switch Input
25 NC(*) Input
26 NC(*) Input
27 Machine select 2 Input
28 NC(*) Input
29 NC(*) –
30 NC(*) Input
31 NC(*) –
Input/
32 CANO_H
output
Input/
33 NC(*)
output
34 GND (232C GND) –
35 Service pressure switch Input
36 NC(*) Input
37 Machine select 1 Input
38 Swing prorix switch Input
39 NC(*) –
40 NC(*) Input
*: Never connect to NC or malfunctions or failures will
occur.
36 PC340-7
10 Structure, function and maintenance standard UEN00277-00
CN-CP02
Input/
Pin No. Signal name
output
1 VB (Controller PWR) Input
2 VIS (Solenoid PWR) Input
3 SOL_COM (SOL. COM. GND) –
4 Battery relay drive signal output
5 NC(*) output
6 LS-EPC output
7 Travel junction solenoid output
8 NC(*) output
9 (Bucket digging pressure switch) Input
10 Boom rise pressure switch Input
11 VB (Controller PWR) Input
12 VIS (Solenoid PWR) Input
13 SOL_COM (SOL. COM. GND) –
14 KEY_SIG Input
15 NC(*) output
16 PC-EPC output
17 Merge divider solenoid output
18 NC(*) output
19 Bucket dump pressure switch Input
20 Boom down pressure switch Input
21 GND (Controller GND) –
22 NC(*) Input
23 SOL_COM (SOL. COM. GND) –
24 KEY_SIG Input
25 NC(*) output
26 ATT currented output
27 Travel speed solenoid output
28 2-stage relief solenoid output
29 Swing pressure switch Input
30 (Arm digging pressure switch) Input
31 GND (Controller GND) –
32 GND (Controller GND) –
33 GND (Controller GND) –
34 NC(*) –
35 NC(*) output
36 NC(*) output
37 Swing parking brake SOL output
38 NC(*) output
39 Travel pressure switch Input
40 Arm dump pressure switch Input
*: Never connect to NC or malfunctions or failures will
occur.
PC340-7 37
UEN00277-00 10 Structure, function and maintenance standard
Monitor system 1
38 PC340-7
10 Structure, function and maintenance standard UEN00277-00
Machine monitor
Outline
q The machine monitor has the functions to dis-
play various items and the functions to select
modes and electric parts.
q The machine monitor has a CPU (Central Pro-
cessing Unit) in it to process, display, and out-
put the information.
q The monitor display employs an LCD (Liquid
Crystal Display). The switches are flat sheet
switches.
PC340-7 39
UEN00277-00 10 Structure, function and maintenance standard
CN-1 CN-3
Input/ Input/
Pin No. Signal name Pin No. Signal name
output output
1 Key ON Input 1 NC (*) Input
2 Key ON Input 2 NC (*) Input
3 Window washer motor output output 3 NC (*) Input
4 Starting signal Input 4 NC (*) Input
5 Limit switch (W) Input 5 NC (*) Input
6 GND – 6 NC (*) Input
7 GND – 7 RS230C CTS Input
8 VB+ Input 8 RS230C RXD Input
9 Wiper motor (+) output Input/
9 RS230C RXD
10 Wiper motor (–) output output
11 Buzzer ON signal Input Input/
10 RS230C RXD
12 Limit switch (P) Input output
11 BOOTSW Input
12 NC (*) Input
CN-2
13 GND –
Input/
Pin No. Signal name 14 CAN (SHIELD) Input
output
15 CAN (+) Input
1 Engine coolant temperature Input
16 CAN (–) Input
2 Fuel level Input
*: Never connect to NC or malfunctions or failures will
3 Radiator coolant level Input
occur.
4 (Hydraulic oil level) Input
5 Air cleaner clogging Input
6 NC (*) Input
7 Engine oil pressure Input
8 Engine oil level Input
Input/
9 Network signal
output
Input/
10 Network signal
output
11 Charge amount Input
12 Hydraulic oil temperature (analog) Input
13 GND (for analog signal) –
14 Buzzer drive Input
15 Limit switch (window) Input
16 Buzzer cancel Input
17 Swing lock Input
18 Preheating Input
19 Light switch Input
20 Network GND –
*: Never connect to NC or malfunctions or failures will
occur.
40 PC340-7
10 Structure, function and maintenance standard UEN00277-00
1. Wiper monitor
2. Preheating monitor
3. Swing lock monitor
4. Engine coolant temperature monitor
5. Hydraulic oil temperature gauge
6. Engine coolant temperature gauge
7. Working mode monitor
8. Service monitor
9. Travel speed monitor
10. Fuel gauge
11. Fuel level monitor
12. Hydraulic oil temperature monitor
13. Power maximizing monitor
14. Auto-deceleration monitor
15. Engine oil pressure monitor
16. Charge level monitor
17. Radiator coolant level monitor
18. Engine oil level monitor
19. Air cleaner clogging monitor
20. Maintenance time warning monitor
PC340-7 41
UEN00277-00 10 Structure, function and maintenance standard
Engine coolant
temperature
Hydraulic oil
See gauge display on the next page
temperature
Fuel level
42 PC340-7
10 Structure, function and maintenance standard UEN00277-00
Temperature or
Gauge Range Indicator Buzzer sound
volume
A1 105 Red Q
A2 102 Red
Engine coolant tem- A3 100 Green
perature (°C) A4 80 Green
A5 60 Green
A6 30 White
B1 105 Red
B2 102 Red
Hydraulic oil temper- B3 100 Green
ature (°C) B4 80 Green
B5 40 Green
B6 20 White
C1 417 Green
C2 347.5 Green
Fuel level C3 277.5 Green
(l) C4 139 Green
C5 100 Green
C6 62 Red
PC340-7 43
UEN00277-00 10 Structure, function and maintenance standard
Checks before starting (all symbols light up), when maintenance interval is exceeded.
If the checks before starting or maintenance interval is exceeded items light up, the display of the hydraulic
oil temperature gauge and the hydraulic oil temperature monitor disappear and the following symbols are
displayed.
When abnormal,
Engine oil pressure — lights up and buzzer
sounds
Lights up when
Battery charge —
abnormal
When abnormal,
Radiator coolant Lights up when
lights up and buzzer
level abnormal
sounds
Lights up when
Engine oil level —
abnormal
Lights up when
Air cleaner clogging —
abnormal
44 PC340-7
10 Structure, function and maintenance standard UEN00277-00
Displays set
Working mode
mode
Monitor
Displays set
Travel speed
speed
Lights up when
Service meter
Service meter When service meter is working service meter is
indicator
working
PC340-7 45
UEN00277-00 10 Structure, function and maintenance standard
Switches
46 PC340-7
10 Structure, function and maintenance standard UEN00277-00
Auto-deceleration switch
The auto-deceleration switch toggles the auto-
deceleration function on and off. When the working
mode is switched, it is automatically set to ON.
When it is set to ON, the auto-deceleration monitor
appears.
PC340-7 47
UEN00277-00 10 Structure, function and maintenance standard
Method of use
a Carry out the setting on the normal screen
P mode, E mode
1) Press select switch (1).
4) After completing the level selection, press
input confirmation switch (3). The selec-
tion flow level is confirmed and the screen
moves to the normal screen. When input
confirmation switch (3) is pressed, the
attachment flow is updated. The relation-
ship between the flow level and the flow is
shown in the table below.
Flow level Flow (l/min) Remarks
8 530 Default
7 430
6 370
5 300
4 230
2) When the screen changed as below,
select "01" by operating switch (2), and 3 165
press input confirmation switch (3). 2 100
1 30
a Flow level is not changed until the
input confirmation switch is pressed.
It is, therefore, possible not to change
the flow level by pressing return
switch (4) to return to the normal
screen.
48 PC340-7
10 Structure, function and maintenance standard UEN00277-00
7) Select one of the three flow levels by mov- Control switch Actuation
ing the cursor with operation switch (2) or Flow level bar graph
entering the relevant number (01, 02 or extends to the right
03) with the 10-key pad. Flow level bar graph
retracts to the left
03 150
a Flow level is not finalized until input
confirmation switch (3) is pressed.
8) Pressing input confirmation switch (3) Returning to the normal screen by
after selecting the flow level finalizes the pressing return switch (4) will leave
selection. the flow level setting unchanged.
a Flow level is not finalized until the
input confirmation switch is pressed.
Returning to the normal screen by
pressing return switch (4) will leave
the flow level setting unchanged.
PC340-7 49
UEN00277-00 10 Structure, function and maintenance standard
11) Check the set value with the working 3) The setting value adjusting screen shown
mode monitor. The relationship between below is displayed. Operate operation
the display level and the set value is switch (2) to select the setting value.
shown in the table below. Relationship between fuel mileage and
work rate for each of the setting values is
Display level Set value (l/min.)
as follows.
8 250 or 260 E0: Initial Setting Value
7 230 or 240 (highest priority is placed on work
6 210 or 220 rate.)
E1: Economy Adjusting 1
5 190 or 200
(Priority is placed on work rate.)
4 170 or 180 E2: Economy Adjusting 2
3 150 or 160 (Priority is placed on fuel mileage.)
2 130 or 140 E3: Economy Adjusting 3
(highest priority is placed on fuel mile-
1 120
age.)
50 PC340-7
10 Structure, function and maintenance standard UEN00277-00
PC340-7 51
UEN00277-00 10 Structure, function and maintenance standard
52 PC340-7
10 Structure, function and maintenance standard UEN00277-00
01 Contrast
02 Brightness
PC340-7 53
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54 PC340-7
10 Structure, function and maintenance standard UEN00277-00
User code display function q If there are more than one service or failure
q If there is any problem in operating the codes, they are displayed in turn every 2 sec-
machine, the user code is displayed on the onds.
monitor to advise the operator of the steps to q Any service codes/failure codes that are not
take. This code appears on the normal screen. related to the displayed user code is displayed
q On the normal screen, the user code is dis- with this function.
played on the portion for the hydraulic oil tem-
perature gauge in the center of the screen.
PC340-7 55
UEN00277-00 10 Structure, function and maintenance standard
Sensor 1
q The signals from the sensors are input to the
monitor panel directly.
q Either side of a sensor of contact type is
always connected to the chassis ground.
Type of When When
Sensor name
sensor normal abnormal
ON OFF
Hydraulic oil level Contact
(Closed) (Open)
Hydraulic oil Resis-
– –
temperature tance
Resis-
Coolant temperature – –
tance
Resis-
Fuel level – –
tance
OFF ON
Air cleaner clogging Contact
(Closed) (Open)
1. Connector
2. Bracket
3. Float
4. Switch
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10 Structure, function and maintenance standard UEN00277-00
1. Thermistor 4. Tube
2. Body 5. Wire
3. Tube 6. Connector
1. Float 3. Cover
2. Connector 4. Variable resistor
PC340-7 57
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58 PC340-7
10 Structure, function and maintenance standard UEN00277-00
PC340-7 59
UEN00277-00 10 Structure, function and maintenance standard
KOMTRAX terminal 1
1. DRC connector connection (40 poles) q The KOMTRAX terminal obtains various kinds
2. (Do not connect any cable) of machine information from the network sig-
3. GPS antenna connection nals and input signals in the machine and
4. Film antenna connection transmits them via the wireless communication
antenna. It contains a CPU (Central Process-
ing Unit) and has wireless communication
function and GPS function.
q This terminal has an LED lamp unit and a 7-
segment display lamp unit used for inspection
and troubleshooting.
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10 Structure, function and maintenance standard UEN00277-00
PC340-7 61
UEN00277-00
© 2006 KOMATSU
All Rights Reserved
Printed in Belgium 05-06 (00)
62