Wacker Neuson 38Z3, Руководство по обслуживанию

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SERV-HB 38Z3 EN – Edition 2.1 * 38z3s510.fm
The
carriage rotation, boom swivel or stick retraction is carried out.
The pilot control pressure at the SH input causes the piston in the brake release valve to
shift to active state (brake release). This directs the pilot control pressure at the PG input
to the brake cylinder and releases the brake.
•
Movement: upper carriage rotation, boom swivel or stick retraction
•
Pilot control pressure is present at the SH input
•
The piston of the brake release valve moves to work position
•
Pilot control pressure is directed to the brake piston
•
Brake is released
The shuttle valve causes the pilot control pressure to drop and the SH input is
unpressurised upon termination of upper carriage rotation, boom swivel or stick retraction.
The piston in the brake release valve switches to home position (brake) if there is no
pressure at the SH input. The pressure in the brake cylinder escapes via the brake release
valve to the leak oil system. This enables the brake with some delay (depending on oil
viscosity and brake valve leakage).
•
End of movement: upper carriage rotation, boom swivel or stick retraction
•
The pilot control pressure at the SH input drops
•
The piston of the brake release valve moves to home position
•
No more pilot control pressure on the brake piston
•
The oil in the brake piston flows to the tank via a throttle orifice
•
The brake is enabled
Fig. 3: Shuttle valve
5-27
Hydraulic system
Parking brake/multidisc brake function
Opening the brake
shuttle valve
e ( Fig. 3 ) directs the pilot control pressure to the SH input if upper
Closing the brake
Time for releasin g the brake: 3.7 sec ± 1.2 at 50 °C (122°F) oil temperatu re