7.
SWING OPERATION ARM CYLINDER BUCKET CYLINDER BOOM CYLINDER SWING MOTOR SH SH DB DB PG PG M M PB PA A(CW) B(CCW) PB PA A(CW) B(CCW) TRAVEL MOTOR pa5 pc1 pa9 pa11 pb8 pa8 A7 pb3 pb7 pa7 B7 pc7 TURNING JOINT pc6 A6 B6 RCV PEDAL P T TRAVEL pa6 pb6 pb1 pa1 (4) (1) (2) (3) A1 A2 SWING ARM BUCKET BOOM P T P T Dr#, dr# FRONT PUMP REAR PUMP PILOT PUMP (4) (1) (2) (3) (4) (1) (2) (3) A5 Pk (T/Joint) A1 A2 A3 PH (MCV) a b d e f g h j c d1 h1 PS PS PS h2 P3 P2 P4 PP(MCV) PG (S/Motor) pb5 pa2 pb2 pa9 pb8 pa8 pa7 pb7 T(dr1) P1 HYDRAULIC TANK RELIEF VALVE LINE FILTER 900L3HC16 When the LH control lever is pushed left or right, the swing spool in the main control valve is moved to the left or right swing position by the pilot oil pressure from the remote control valve.
The oil from the A1 pump flows into the main control valve and then goes to the swing motor. At the same time, the return oil from the swing motor returns to the hydraulic oil tank through the swing spool in the main control valve. When this happens, the upper structure swings to the left or right. The swing parking brake, make up valve and the motor brake valve are provided in the swing motor. The cavitation which will happen to the swing motor is also prevented by the make up valve in the swing motor itself.
3-18 ps1 T3 T1 pa11 T2 T4 ps2 pa10 D p B5 A5 pb pb5 p B B A A D p p R1 c1 9 ARM1 a5 PO B4 A4 1 OPTION 1 R7 c7 A3 B3 b3 B9 A9 pb9 ARM2 B8 A8 BUCKET DR2 pc2 p B2 pa3 BOOM2 A2 pb2 SWING DR3 pa2 pc6 B1 A1 pp ab 11 TRAVEL-LH pr1 P1 PSPT PP PA P SH PS