Compensation Spool - Kubota KX080-3 Workshop Manual

WSM KX080-3 Service

5) Compensation spool

1. The compensation spool moves based on a balance between the PC pressure and the load pres-
sure. However, the symptom depends on the position in which a stick occurs.
2. If a stick occurs in the stroke-0 position, i.e. in a state of the so-called under lap, the cylinder speed
decreases, since the opening in the spool is small. The speed is almost the same as that obtained
when other sections are relieved and manipulated simultaneously.
(The simultaneous manipulation must be in the horsepower control area.)
3. If the compensation spool gets stuck in the full open position during the simultaneous manipulation
under light and heavy loads, the pump flow is apt to be directed to the light load side when the
compensation spool on the light load side gets stuck in the full open position, making it difficult to
control the heavy load side.
4. If a stick occurs in the intermediate stroke position, it is difficult to control the heavy load side up to
the stick position of the compensation spool.
In the operation conditions beyond the stick position, the cylinder speed is lower than normal.
5. What will happen if the compensation spool is misassembled?
In a state of the under lap, compare the cylinder speed with a normal machine.
The cylinder speed decreases with decreasing under lap opening area.
6. If the compensation spool gets stuck as shown above, disassemble and clean the spool. Elimi-
nate the cause of trouble completely and reassemble the spool. Replace parts if necessary. In
some cases, replace the section assembly.
IV-S-11
Hydraulic system