6. SWING PARKING BRAKE RELEASE 6.
SWING PARKING BRAKE RELEASE ARM CYLINDER BUCKET CYLINDER BOOM CYLINDER PG AU AU PG DR DR MB MU MA MB MU MA ps1 ps2 T3 T1 T2 T4 VA(CCW) VB(CW) VA(CCW) VB(CW) (Td#) TRAVEL MOTOR A SWING PARKING SOLENOID VALVE T P [Td#] TRAVEL P T pb6 pa1 pb1 pa6 (2) (1) (4) (3) BOOM P T BUCKET ARM P T SWING T1 PUMP A1 PUMP A2 P T T2 T3 dr# PILOT PUMP (2) (1) (3) (4) (2) (3) (1) (4) A D E F G H J B PH (MCV) F (T/JOINT) a b d e f g h j pa2 pb2 PS c h1 j1 PS PS d1 f1 g1 PS PS PS e2 PS A1 A2 A5 P3 P4 Pi(D/C VALVE) P(2-EPPR) PP(MCV) Td# P pb9 pb5 T A B C (Td#) P2 P1 HYDRAULIC TANK pa9 pc1 pa5 pa8 pa11 pb8 pc6 pb3 pb7 pc2 pa7 pa3 LINE FILTER 480A3HC07 When the swing control lever is tilted, the swing solenoid valve is shifted to the down ward by the MCU that senses the pilot pressure of the swing control lever.
The discharged oil from pilot pump flows to swing motor PG port through the swing solenoid valve. This pressure is applied to swing motor disc, thus the brake is released. When the swing control lever is set in the neutral position, the swing solenoid valve is shifted to the up ward, oil in the swing motor disc cylinder is drained through the the swing solenoid valve, thus the brake is applied. 3-12 A5 pb5 ARM 1 pa5 B4 A4 pb4 pa4 OPTION A3 B3 pb3 B2 pa3 BOOM 2 A2 (RH) TRAVEL(LH TRAVEL STRAIGHT A6 pb6 pa6 ) P3 P2 CRO P1 P2 P3