Komatsu HD785-7 Service Manual
GROSS HORSEPOWER
895 kW
1,200 HP
NET HORSEPOWER
879 kW
1,178 HP
RATED GVW
163780 kg
Photos may include optional equipment.
HD
785
HD785-7
OFF-HIGHWAY TRUCK
W
ALK
-A
ROUND
HD785-7 O FF-HIGHWAY T R UCK
Productivity and Economy Features
● High performance Komatsu SAA12V140E-3 engine
Net horsepower
879kW 1,178HP
● Mode selection system with Variable HorsePower Control (VHPC)
● Two-speed selective reverse gears of RH and RL
● Anti-pitching 4-wheel oil-cooled multiple-disc retarder (AP-FOUR)
Retarder capacity
1092kW 1,464HP (Continuous descent)
● Automatic retard speed control (ARSC) as standard
Harmony with Environment
● Komatsu SAA12V140E-3 engine
(EPA Tier 2 emission certified)
● Lead-free radiator
● Low operation noise
● Low fuel consumption
HD785
-7
OFF-HIGHWAY TRUCK
32
GROSS HORSEPOWER
895 kW 1,200 HP/1900 min
-1
NET HORSEPOWER
879 kW 1,178 HP/1900 min
-1
RATED GVW
163780 kg
Operator Environment and Safety
● Spacious cab with excellent visibility
● Ergonomically designed cab
● Easy-to-see instrument panel
● Synchronous control of engine and transmission
● Advanced K-ATOMiCS with “Skip-shift” function
● Viscous cab mounts
● Electronic hoist control system
● Built-in ROPS/FOPS cab
● Parking brakes on 4-wheels
● Supplementary steering
● Pedal-operated secondary brake
● Three-mode automatic hydropneumatic
suspension (Option)
Reliability Features
● Flat face-to-face O-ring seals
● Sealed DT connectors
Easy Maintenance
● Oil-cooled multiple-disc brakes
and fully hydraulic controlled
braking system
● Extended oil change interval
● Disc wheels (flange type rims)
● Electric circuit breakers
● KOMTRAX Plus
Automatic selection Selection with the switch
700
800
900
kW
P
E
Power
mode
Economy
mode
895kW
(1200HP)
809kW
(1085HP)
750kW
(1005HP)
698kW
(936HP)
4
P
RODUCTIVITY &
E
CONOMY
F
EATURES
HD785-7 O FF-HIGHWAY T R UCK
Mode Selection System with VHPC
The system allows selection of the appropriate engine output mode <Power mode > or <Economy mode>, according
to the working condition. The mode is easily selected with
the switch in the operator’s cab. When the key switch is
turned on, Economy mode is selected automatically. Power
mode can be selected by using the switch when needed.
High Performance Komatsu SAA12V140E-3
Engine
This engine delivers faster acceleration and higher travel
speeds with high horsepower per ton. Advanced technologies, such as High Pressure Common Rail injection system
(HPCR), air-to-air aftercooler and efficient turbo-charger
enables the engine to be EPA Tier 2 emission certified.
High torque at low speed, impressive acceleration, and low
fuel consumption ensure maximum productivity.
Drive downhill
at a constant
speed
UP
SET
DOWN
CANCEL
AUTO RETARD
SPEED CONTROL
HD785-5
HD785-7
(AP-FOUR)
R : Retarder
( 2-Wheel )
F, R : Retarder
( 4-Wheel )
F7-R2 (RH/RL) Fully Automatic Transmission
The transmission is configured with 7 forward and 2
reverse gears. Fully automatic control is applied to all forward gears and an optimum gear is automatically selected
according to the travel speed
and engine speed. The shifting point is automatically
selected depending on the
acceleration of the machine
to reduce excessive fuel
consumption.
Variable HorsePower Control (VHPC)
Both in Power and Economy modes, the VHPC system
detects whether the machine is loaded or unloaded and
selects the optimum horsepower setting mode, providing
both high production and low fuel consumption.
Power mode: Makes best use of the horsepower to
attain optimal production. This mode is suitable for operations including uphill travel loaded where throughput is the
top priority.
Economy mode: Sets the maximum horsepower at a
lower level to reduce fuel consumption. The machine maintains sufficient power for normal operation in this mode.
Two-speed Selective Reverse Gears (RH/RL)
In order to meet various operating conditions, two reverse
gears are provided. The switch on the panel allows the
operator to usually select the appropriate gear for the application, RH or RL depending on the job site conditions.
Furthermore, the reverse gear is equipped with a lockup
clutch, just like forward gears, allowing the operator to
reverse the machine without concern of overheating.
RH
Suitable for normal operation. Thanks to the lockup clutch,
the machine can be reversed at higher speed.
RL
Suitable for operation where steep grades are existing.
5
HM350-1
ARTICULATED DUMP TRUCK
HD785
-7
OFF-HIGHWAY TRUCK
Anti-pitching 4-wheel Oil-cooled Multiple Disc
Retarder (AP-FOUR)
The machine is equipped with 4-wheel retarder AP-FOUR
that applies retarding force on all four wheels. With this
retarder, the retarding force is shared between four wheels.
This reduces the possibility of tire-lock and enables effective use of retarder capacity, allowing stable downhill travel.
The machine descends slopes smoothly and comfortably
without machine body pitching since retarding force on
front and rear wheels is controlled independently.
Auto Retard Speed Control (ARSC)
ARSC allows the operator to simply set the downhill travel
speed and descend grades at a constant speed. This
allows the operator to concentrate on steering. The speed
can be set at increments of
1 km/h per click (within ±5
km/h
) to match the optimum speed for the slope. The
retarder cooling oil temperature is constantly monitored and
the descent speed is automatically reduced, if necessary.
Drive downhill
at a constant
speed
UP
SET
DOWN
CANCEL
AUTO RETARD
SPEED CONTROL
HD785-5
HD785-7
(AP-FOUR)
R : Retarder
( 2-Wheel )
F, R : Retarder
( 4-Wheel )
• Retarder absorbing capacity
1092 kW 1,464 HP (continuous descent)
• Brake surface area
Front total :
37467 cm
2
Rear total : 72414 cm
2
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