Case CX17B Mini Excavator Service Manual

Table of Content (Service Manual)

1. Index
2. Specification
3. Maintenance
4. System
5. Disassembling
6. Troubleshooting
7. E/G

Manual Extract:
SLEW OPERATING CIRCUIT

Pilot oil hydraulic system with operating lever

22.3.4.1 Slew (left) Operating Circuit (1) Pilot Circuit

1. Slew Valve Spool Shifting
With operation for slew (left), the pilot secondary pressure oil is generated from the pilot valve (11), and led to the Pa1 port of control valve (2) to shift the slew valve spool.

(2) Main Circuit
1. Supply Circuit for Slewing Motor (3) The oil delivered from the P3 port on hydraulic oil pump (1) is supplied to the A port on slewing motor (3) through the P3 port on control valve (2) and slew valve to drive the slewing motor.
2. Slewing Motor (3)
a. The relief valve (304) relieves rapidly increased pressure at start and stop of the machine to ease shock.
b. The make-up valve (check valve) (305) has a function to replenish oil from the return oil circuit that is led to the tank [T2 port on control valve (2)] to the slewing motor, to prevent the slewing motor from the cavitation due to negative pressure generated in it because of inertia on the slewing mass.