System Operation; Normal Operation - Komatsu 730E Operation & Maintenance Manual

Maintenance - Section 42
Page 42-6

SYSTEM OPERATION

Normal Operation

Refer to Figure 42-5 and 42-6:
1. During truck operation, lubrication cycle timer
(1, Figure 42-6) will energize the system at a
preset time interval.
2. The lubrication cycle timer provides a 24VDC
signal through normally closed relay board (12)
used to energize pump solenoid valve (3, Fig-
ure 42-5), allowing hydraulic oil provided by the
truck steering pump circuit to flow to the pump
motor and initiate a pumping cycle.
3. The hydraulic oil pressure from the steering cir-
cuit is reduced to 2 240 to 2 413 kPa (325 to
350 psi) by pressure reducing valve (4, Figure
42-5) before entering the motor. In addition, the
amount of oil supplied to the pump is limited by
flow control valve (6). Pump pressure can be
read using pressure gauge (5) mounted on the
manifold.
4. With oil flowing into the hydraulic motor, the
grease pump will operate, pumping grease from
the reservoir to vent valve (11) and then to
injectors (13). Pressure switch (9) prevents over
pressurization.
5. During this period, the injectors will meter the
appropriate amount of grease to each lubrica-
tion point.
1. Hydraulic Oil Return
2. Hydraulic Oil Supply
3. Pump Solenoid Valve
4. Pressure Reducing Valve
5. Pressure Gauge
10. During the normal lubrication cycle, if grease
FIGURE 42-5. HYDRAULIC SCHEMATIC
6. Flow Control Valve
7. Hydraulic Motor
8. Grease Pump
9. Pressure Switch (NO)
10. Unloader Valve
Automatic Lubrication System
6. When 20 685 kPa (3,000 psi) grease pressure
reaches pressure switch (4, Figure 42-6) set-
ting, the switch contacts will close and energize
relay K1 (12), removing power from grease
pump solenoid valve (5) and the pump will stop.
The relay will remain energized until grease
pressure drops and the pressure switch opens
again or until the timer turns off.
7. After the pump solenoid valve is de-energized,
hydraulic pressure in the manifold drops and
vent valve (11, Figure 42-5) will open, releasing
grease pressure in the lines to the injector
banks. When this occurs, the injectors are then
able to recharge for the next lubrication cycle.
8. Unloader valve (10) prevents excessive grease
pressure if the pressure switch fails to close and
shut off the hydraulic supply to the pump. The
unloader will open at approximately 27 580 kPa
(4,000 psi).
9. The system will remain at rest until the lubrica-
tion cycle timer turns on and initiates a new
grease cycle.
pressure fails to reach 13 790 kPa (2,000 psi) at
the pressure switch located on the rear axle
housing, an amber indicator light will illuminate
on the overhead panel.
11. Vent Valve
12. Orifice
13. Injector Bank
07/09 0M4211