Komatsu PC150-6K, PC150LC-6K Excavator Service Manual

Table of Contents

01 GENERAL ……………………………………01-1
10 STRUCTURE AND FUNCTION ……………………..10-1
20 TESTING, ADJUSTING AND TROUBLESHOOTING ……… 20-1
30 DISASSEMBLY AND ASSEMBLY …………………… 30-1
40 MAINTENANCE STANDARD ……………………… 40-I

GENERAL
This section lists the general machine dimensions, performance specifications, component weights, and fuel, coolant and lubricant specification charts.

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
This section explains the structure and function of each component. It serves not only to give an understanding of the structure, but also serves as reference material for troubleshooting.

TESTING, ADJUSTING AND TROUBLESHOOTING
This section explains checks to be made before and after performing repairs, as well as adjustments to be made at completion of the checks and repairs. Troubleshooting charts correlating Problems to Causes are also mention in this section.

DISASSEMBLY AND ASSEMBLY KOMATSU Excavator PC150-6K, PC150LC-6K

This section explains the order to be followed when removing, installing, disassembling or assembling each component, as well as precautions to be taken for these operations.

Operation of brake when traveling downhill Travel control . 2)
If the machine tries to run away when traveling downhill, the motor will turn under no load, so the pressure at the motor inlet port will drop, and the pressure in chamber Sl through offices El and E2 will also drop.
When the pressure in chamber Sl drops below the spool switching pressure, spool (19) is returned to the left in the direction of the arrow by spring (20), and outlet port MB is throttled.
(Fig.4) E2

As a result, the pressure at the outlet port side rises, resistance is generated to the rotation of the motor, and this prevents the machine form running away.
In other words, the spool moves to a position where the pressure at outlet port MB balances the pressure at the inlet port and the force generated by the weight of the machine. It throttles the outlet port circuit and controls the travel speed according to the amount of oil discharged from the pump. (Fig. 4)