PDF Service Repair Manual Komatsu PC270-7 Hydraulic Excavator - 15 MB
The complete service and repair manual for the Komatsu PC270-7 Hydraulic Excavator provides all the information you need for maintenance and complex repairs.
This guide offers detailed, step-by-step instructions, schematics, and specifications.
It is an essential tool for any technician working on the PC270-7.
Keep your excavator performing at its best by following the manufacturer's prescribed service procedures.
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--- Page 1 ---
SEBM030406
MACHINE MODEL SERIAL NUMBER
PC270-7 10001 and up
• This shop manual may contain attachments and optional equipment that are not available in
your area. Please consult your local Komatsu distributor for those items you may require.
Materials and specifications are subject to change without notice.
• PC270-7 mount the SAA6D102E-2 engine.
For details of the engine, see the 102 Series Engine Shop Manual.
© 2005
All Rights Reserved
Printed in Japan 08-05 (01) 00-1
(6)
--- Page 3 ---
FOREWORD HOW TO READ THE SHOP MANUAL
HOW TO READ THE SHOP MANUAL REVISED EDITION MARK
VOLUMES When a manual is revised, an edition mark
Shop manuals are issued as a guide to carrying out ((1)(2)(3)....) is recorded on the bottom of the pages.
repairs. They are divided as follows:
Chassis volume: Issued for every machine model REVISIONS
Engine volume: Issued for each engine series
Each issued as one Revised pages are shown in the LIST OF REVISED
Electrical volume:
}
Attachments volume: · volume to cover all
models
PAGES next to the CONTENTS page.
SYMBOLS
These various volumes are designed to avoid dupli-
cating the same information. Therefore, to deal with So that the shop manual can be of ample practical
all repairs for any model , it is necessary that chas- use, important safety and quality portions are
sis, engine, electrical and attachment volumes be marked with the following symbols.
available.
DISTRIBUTION AND UPDATING
Any additions, amendments or other changes will be
sent to KOMATSU distributors. Get the most up-to- Symbol Item Remarks
date information before you start any work.
k
Special safety precautions
Safety are necessary when per-
forming the work.
FILING METHOD
1. See the page number on the bottom of the page. Special technical precau-
File the pages in correct order. tions or other precautions
2. Following examples show how to read the page a Caution for preserving standards
number. are necessary when per-
forming the work.
Example 1 (Chassis volume):
Weight of parts of sys-
10 - 3
4
tems. Caution necessary
Weight when selecting hoisting
Item number (10. Structure and wire, or when working pos-
Function) ture is important, etc.
Consecutive page number for each
3
Places that require special
item. Tightening
attention for the tightening
torque
torque during assembly.
Example 2 (Engine volume):
2
Places to be coated with
12 - 5 Coat adhesives and lubricants,
etc.
Unit number (1. Engine) Places where oil, water or
5
Item number (2. Testing and Adjust- Oil, water fuel must be added, and
ing) the capacity.
Consecutive page number for each
Places where oil or water
6
item.
Drain must be drained, and
quantity to be drained.
3. Additional pages: Additional pages are indicated
by a hyphen (-) and number after the page
number. File as in the example.
Example:
10-4 12-203
10-4-1 12-203-1
Added pages
10-4-2 12-203-2
10-5 12-204
00-6
--- Page 4 ---
FOREWORD CONVERSION TABLE
CONVERSION TABLE
METHOD OF USING THE CONVERSION TABLE
The Conversion Table in this section is provided to enable simple conversion of figures. For details of the
method of using the Conversion Table, see the example given below.
EXAMPLE
• Method of using the Conversion Table to convert from millimeters to inches
1. Convert 55 mm into inches.
(1) Locate the number 50 in the vertical column at the left side, take this as (A), then draw a horizontal line
from (A).
(2) Locate the number 5 in the row across the top, take this as (B), then draw a perpendicular line down
from (B).
(3) Take the point where the two lines cross as (C). This point (C) gives the value when converting from
millimeters to inches. Therefore, 55 mm = 2.165 inches.
2. Convert 550 mm into inches.
(1) The number 550 does not appear in the table, so divide by 10 (move the decimal point one place to the
left) to convert it to 55 mm.
(2) Carry out the same procedure as above to convert 55 mm to 2.165 inches.
(3) The original value (550 mm) was divided by 10, so multiply 2.165 inches by 10 (move the decimal point
one place to the right) to return to the original value. This gives 550 mm = 21.65 inches.
(B)
Millimeters to inches
1 mm = 0.03937 in
0 1 2 3 4 5 6 7 8 9
0 0 0.039 0.079 0.118 0.157 0.197 0.236 0.276 0.315 0.354
10 0.394 0.433 0.472 0.512 0.551 0.591 0.630 0.669 0.709 0.748
20 0.787 0.827 0.866 0.906 0.945 0.984 1.024 1.063 1.102 1.142
30 1.181 1.220 1.260 1.299 1.339 1.378 1.417 1.457 1.496 1.536
40 1.575 1.614 1.654 1.693 1.732 1.772 1.811 1.850 1.890 1.929
(C)
(A) 50 1.969 2.008 2.047 2.087 2.126 2.165 2.205 2.244 2.283 2.323
60 2.362 2.402 2.441 2.480 2.520 2.559 2.598 2.638 2.677 2.717
70 2.756 2.795 2.835 2.874 2.913 2.953 2.992 3.032 3.071 3.110
80 3.150 3.189 3.228 3.268 3.307 3.346 3.386 3.425 3.465 3.504
90 3.543 3.583 3.622 3.661 3.701 3.740 3.780 3.819 3.858 3.898
00-16
--- Page 5 ---
GENERAL SPECIFICATIONS
SPECIFICATIONS
Machine model PC270-7
Serial Number 10001 and up
Bucket capacity m³ 1.26
Operating weight kg 26,900
Max. digging depth mm 6,460
Working ranges
Max. vertical wall depth mm 5,650
Max. digging reach mm 10,100
Max. reach at ground level mm 9,900
Max. digging height mm 10,000
Max. dumping height mm 7,035
Max. digging force kN {kg} 184 {18,700}
Performance
(using power max. function) (198.1 {20,197})
Swing speed rpm 10.5
Swing max. slope angle deg. 20
Travel speed km/h Lo: 3.0 ( 2.8) Mi: 4.1 ( 3.3)
Hi: 5.5 ( 4.5)
Gradeability deg. 35
Ground pressure kPa {kg/cm²} 54.9 {0.56}
[standard shoe width] [mm] [600]
Overall length (for transport) mm 9,790
Overall width mm 3,190
Overall width of track mm 3,190
Overall height (for transport) mm 3,210
Overall height to chassis mm 3,100
Dimensions
Ground clearance to bottom of upper structure mm 1,186
Min. ground clearance mm 498
Tail swing radius mm 2,940
Min. swing radius of work equipment mm 3,430
Height of work equipment at min. swing radius mm 8,150
Length of track on ground mm 3,700
Track gauge mm 2,590
Height of machine cab mm 2,560
: With optional heavy duty travel motor.
01-4 PC270-7
--- Page 6 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD FINAL DRIVE
12
1. Level plug
2. Drain plug
3. No. 1 planetary gear (No. of teeth: 46)
4. No. 1 sun gear (No. of teeth: 11)
5. No. 2 sun gear (No. of teeth: 19)
6. No. 1 planetary carrier
7. No. 2 planetary carrier
8. Cover
9. Ring gear (No. of teeth: 97)
10. Hub
11. Sprocket
12. Floating seal
13. Travel motor
14. No. 2 planetary gear (No. of teeth: 38)
SPECIFICATIONS
Reduction ratio:
11 + 106 19 + 97
¤ ----------------------- × ------------------- + 1 ¤ 63.938
11 19
Unit: mm
No. Check item Criteria Remedy
Backlash between No. 1 sun gear and Standard clearance Clearance limit Replace
15
No. 1 planetary gear 0.12 ~ 0.44 0.90
Backlash between No. 1 planetary gear
16 0.18 ~ 0.62 1.20
and ring gear
Backlash between No. 2 planetary car-
17 0.06 ~ 0.25 —
rier and motor
Backlash between No. 2 sun gear and
18 0.15 ~ 0.51 1.00
No. 2 planetary gear
Backlash between No. 2 planetary gear
19 0.19 ~ 0.66 1.30
and ring gear
Backlash between No. 2 planetary car-
20 0.39 ~ 0.80 1.60
rier and No. 2 sun gear
21 Amount of wear on sprocket tooth Repair limit: 6
Rebuild or
Standard size Repair limit
22 Width of sprocket tooth replace
87 84
PC270-7 10-7
--- Page 7 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD TRACK SHOE
12
TRACK SHOE
★ P portion shows the link of bushing press fitting end.
10-18 PC270-7
--- Page 8 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD HYDRAULIC PUMP
12
Operation
1) Operation of pump
i Cylinder block (7) rotates together with
shaft (1), and shoe (5) slides on flat surface
A.
When this happens, rocker cam (4) moves
along cylindrical surface B , so angle α
between center line X of rocker cam (4) and
the axial direction of cylinder block (7)
changes. (Angle α is called the swash plate
angle.)
ii Center line X of rocker cam (4) maintains
swash plate angle α in relation to the axial
direction of cylinder block (7), and flat sur-
face A moves as a cam in relation to shoe
(5).
In this way, piston (6) slides on the inside of
cylinder block (7), so a difference between
volumes E and F is created inside cylinder
block (7). The suction and discharge is car-
ried out by this difference F - E.
E
In other words, when cylinder block (7)
rotates and the volume of chamber E
becomes smaller, the oil is discharged dur-
ing that stroke. On the other hand, the vol-
ume of chamber F becomes larger, and as
the volume becomes bigger, the oil is
sucked in.
iii If center line X of rocker cam (4) is in line
with the axial direction of cylinder block (7)
(swash plate angle = 0), the difference
between volumes E and F inside cylinder
block (7) becomes 0, so the pump does not
carry out any suction or discharge of oil.
(In actual fact, the swash plate angle never
becomes 0.)
10-28 PC270-7
--- Page 9 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD HYDRAULIC PUMP
12
• Port C of the PC valve is connected to port E
of the LS valve (see (1) LS valve). Self pres-
sure PP1 enters port B and the small diameter
end of servo piston (9), and other pump pres-
sure PP2 enters port A.
• When pump pressures PP1 and PP2 are
small, spool (3) is on the left. At this point,
port C and D are connected, and the pressure
entering the LS valve becomes drain pressure
PT.
PT If port E and port G of the LS valve are
connected (see (1) LS valve), the pressure
entering the large diameter end of the piston
from port J becomes drain pressure PT, PT and
servo piston (9) moves to the right. In this
way, the pump discharge amount moves in
the direction of increase.
• As servo piston (9) moves further, springs (4)
and (6) expand and the spring force becomes
weaker. When the spring force becomes
weaker, spool (3) moves to the right, so the
connection between port C and port D is cut,
and the pump discharge pressure ports B and
C are connected. As a result, the pressure at
port C rises, and the pressure at the large
diameter end of the piston also rises, so the
movement of piston (9) to the right is
stopped.
• In other words, the stop position for piston (9)
(= pump discharge amount) is decided at the
point where the force of springs (4) and (6)
and the pushing force from the PC-EPC valve
solenoid and the pushing force created by the
pressures PP1 and PP2 acting on the spool (3)
are in balance.
10-38 PC270-7
--- Page 10 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD CONTROL VALVE
12
(2/9)
10-48 PC270-7
--- Page 11 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD CONTROL VALVE
Unit: mm
No. Check item Criteria Remedy
Standard size Repair limit
Free length x Installed Installed Free Installed
17 Valve spring Outside diameter length load length load
3.1 N 2.5 N
10.45 x 7 4.8 —
{0.32 kg} {0.26 kg}
70.6 N 56.4 N
18 Unload spring 31.5 x 10.2 26.8 —
{7.2 kg} {5.8 kg}
1.5 N 1.2 N
19 Check valve spring 11.5 x 4.6 8.5 —
{0.15 kg} {0.12 kg} If damaged or
156.8 N 125.5 N deformed, replace
20 Spool return spring 46.6 x 21.8 3.3 —
{16.0 kg} {12.8 kg} spring
177.5 N 142.0 N
21 Spool return spring 64.5 x 32.3 63 —
{18.1 kg} {14.5 kg}
199.8 N 160.0 N
22 Sequence valve spring 70.9 x 18.0 59 —
{20.4 kg} {16.3 kg}
10.4 N 8.3 N
23 Spool return spring 29.9 x 11.0 10.7 —
{1.1 kg} {0.8 kg}
430.2 N 344.2 N
24 Relief spring 34.7 x 10.4 32.3 —
{43.9 kg) {35.1 kg}
PC270-7 10-59
--- Page 12 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD SWING MOTOR
12
1. Brake spring 8. Housing 15. Safety valve
2. Drive shaft 9. Piston 16. Check valve
3. Spacer 10. Cylinder block 17. Check valve spring
4. Case 11. Valve plate 18. Shuttle valve
5. Disc 12. Reverse prevention valve 19. Shuttle valve spring
6. Plate 13. Center shaft
7. Brake piston 14. Center spring
PC270-7 10-69
--- Page 13 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD TRAVEL MOTOR
OPERATION OF MOTOR
1) At low speed (motor swash plate angle at
maximum)
• The solenoid valve is deactivated, so the pilot • At the same time, the pressurized oil at regu-
pressure oil from the main pump does not lator piston (13) passes through orifice c in
flow to port P. regulator valve (21) and is drained to the
For this reason, regulator valve (21) is pushed motor case.
to the right by spring (22). • As a result, rocker cam (3) moves in the maxi-
• Because of this, it pushes slow return valve mum swash plate angle direction, the motor
(8), and the main pressure oil from the control capacity becomes maximum, and the system
valve going to end cover (7) is shut off by reg- is set to low speed.
ulator valve (21).
• Fulcrum a of rocker cam (3) is eccentric to
point of force b of the combined force of the
propulsion force of cylinder (5), so the com-
bined force of the piston propulsion force acts
as a moment to angle rocker cam (3) in the
direction of the maximum swash plate angle.
10-80 PC270-7
--- Page 14 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD TRAVEL PPC SHUTTLE VALVE
12
2. When travel lever is operated
• If the right travel lever is set in the reverse (or • At this time, the right travel reverse (or for-
forward) direction, the right travel reverse (or ward) PPC pressure is applied through orifice
forward) PPC pressure pushes spool (7) to the (6) of piston (4) to the left end of piston (8) to
left (or right). push piston (8) to the right.
• Spool (7) pushes piston (3) to close orifice (5) • When boom RAISE, arm IN, OUT, bucket
and shut off stroke regulation signal chamber CURL, DUMP are operated, spool (1) moves
"a" from the drain circuit of the travel PPC to the left, but the maximum stroke of the
valve. spool is limited to st1, the amount of move-
ment (st2) of piston (8).
10-90 PC270-7
--- Page 15 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD TRAVEL PPC VALVE
12
3) Fine control (control lever returned)
When lever (5) starts to be returned, spool
(1) is pushed up by the force of centering
spring (3) and the pressure at port P1.
P1
Because of this, fine control hole f is con-
nected to drain chamber D, and the pressur-
ized oil at port P1 is released.
If the pressure at port P1 drops too much,
spool (1) is pushed up by metering spring
(2), so fine control hole f is shut off from
drain chamber D. At almost the same time,
it is connected to pump pressure chamber
PP,
PP so the pressure at port P1 supplies the
pump pressure until the pressure recovers
to a pressure equivalent to the position of
the lever.
When the control valve returns, oil in drain
chamber D flows in from fine control hole f’
of the valve on the side that is not moving.
It passes through port P2 and goes to cham-
ber B to charge the oil. (Fig. 3)
4) At full stroke
Lever (5) pushes down piston (4), and
retainer (9) pushes down on spool (1). Fine
control hole f is shut off from drain chamber
D, and is connected to pump pressure
chamber PP.
PP Therefore, the pilot pressure oil
from the main pump passes through fine
control hole f and flows to chamber A from
port P1 to push the control valve spool. The
return oil from chamber B passes from port
P2 through fine control hole f’ and flows to
drain chamber D . (Fig. 4)
10-100 PC270-7
--- Page 16 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD PPC ACCUMULATOR
PPC ACCUMULATOR
1 1. Gas plug
2. Shell
3. Poppet
4. Holder
5. Bladder
2
6. Oil port
SPECIFICATIONS
3
Gas capacity:300 cc (for PPC)
4
5
6
SBP00290
10-110 PC270-7
--- Page 17 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD WORK EQUIPMENT
WORK EQUIPMENT
10-120 PC270-7
--- Page 18 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD ENGINE CONTROL
Governor motor
1. Potentiometer • A potentiometer for feedback is installed to
2. Cover monitor the operation of the motor.
3. Shaft • Revolution of the motor is transmitted
4. Dust seal through the gear to the potentiometer.
5. Bearing
6. Motor Operation
7. Gear While motor is stopped
8. Connector
• Electric power is applied to both phases A
and B of the motor.
Function
• The motor is turned according to the drive
While motor is running
signal from the engine throttle and pump
controller to control the governor lever of the • The engine throttle and pump controller sup-
fuel injection pump. plies a pulse current to phases A and B, and
the motor revolves, synchronizing to the
This motor used as the motive power source
pulse.
is a stepping motor.
10-130 PC270-7
--- Page 19 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD ELECTRONIC CONTROL SYSTEM
12
2) Function to control pump during travel
• When the travel is operated in A operation,
or E or B working mode, the working mode
stays as it is, and the pump absorption
torque and engine speed rise to A travel
mode.
• If the machine travels in mode L, the work-
ing mode and engine speed do not change,
but the pump absorption torque is
increased.
3) Function to control when emergency
pump drive switch is turned ON
• Even if the controller or a sensor has a
trouble, the functions of the machine can
be secured with pump absorption torque
almost equivalent to mode E by turning on
emergency pump drive switch (10).
In this case, a constant current flows from
the battery to the EPC valve for PC and the
oil pressure is sensed by only the EPC
valve for PC.
4) Function of engine drive switch when
emergency occurs
• If there is a failure in the controller or any
problem in the chassis wiring or relays,
and the engine cannot be started because
the engine stop solenoid cannot drive, turn
the switch ON for approx. 5 seconds before
the starting signal comes ON. This makes it
possible to drive the solenoid forcibly.
(However, if current flows through this
solenoid continuously for more than 30
seconds, there is danger that it will burn
out, so correctly control the time that the
current flows.)
10-142 PC270-7
--- Page 20 ---
STRUCTURE, FUNCTION, & MAINTENANCE STANDARD ELECTRONIC CONTROL SYSTEM
12
1) Swing lock and swing holding brake func-
tions 2) Quick hydraulic oil warm-up function when
• The swing lock function (manual) is used to swing lock switch is turned on
lock machine from swinging at any position. • If swing lock switch (4) is turned on, the
The swing holding brake function (automatic) pump-cut function is cancelled and the relief
is used to prevent hydraulic drift after the pressure rises from 34.8 MPa {355 kg/cm²} to
machine stops swinging. 37.2 MPa {380 kg/cm²}. If the work equipment
• Swing lock switch and swing lock/holding is relieved under this condition, the hydraulic
brake oil temperature rises quickly and the warm-up
time can be shortened.
Lock Lock
Function Operation
switch lamp
If swing lever is set in neutral,
Swing swing brake operates in
OFF OFF holding about 5 sec. If swing lever is
brake operated, brake is released
and machine can swing freely.
Swing lock operates and
machine is locked from
Swing swinging. Even if swing lever
ON ON
lock is operated, swing lock is not
reset and machine does not
swing.
Operation of swing holding brake release
switch
• If the controller, etc. has a problem, the swing
holding brake does not work normally, and
the machine cannot swing, the swing lock can
be reset with the swing holding brake release
switch.
Swing hold- ON OFF
ing brake (When control has (When controller is nor-
release switch trouble) mal)
Swing lock
ON OFF ON OFF
switch
Swing Swing Swing lock Swing hold-
Swing brake lock is lock is is turned ing brake is
turned on. canceled. on. turned on.
★ Even if the swing holding brake release