
Reference
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INTRODUCTION
18000 SERIVCE/MAINTENANCE MANUAL
1-34
Published 12-05-17, Control # 035-23
TRAVEL SYSTEM OPERATION
Travel System Components
See Figures
Each travel hydraulic pump drives two crawler system
motors and gearboxes. Each hydraulic pump and motor is
controlled with travel control handle movement and node
controllers. Travel control handles are inoperable when
travel park brake is applied. The gearbox for each crawler is
driven with a flexible shaft connected between the motor
output and drive gearbox input.
To ensure that crane travels in a straight line forward or
reverse direction, each travel drive system has shuttle valves
and pressure senders that monitor hydraulic pressure to
each closed-loop system. When traveling, node-3 controller
monitors information from pressure senders and adjusts
displacement of travel pumps to maintain equal pressure in
each travel drive system. This allows crane to track in a
controlled straight direction.
The source hydraulic pressure for releasing the travel brakes
and enabling motor servo systems is from high pressure
accessory pump system through a pressure reducing valve
at 500 psi (34 bar). Continuous changing of closed-loop fluid
occurs through leakage in pump, motor, and loop flushing
valves that removes 4 gallons per minute (15 L/min) of fluid
to when system pressure is above 200-psi (14 bar).
The travel pumps output can be programmed for 25% to
100% of rated volume. See “Speeds” screen in Crane
Diagnostics in Section 10 of the Service/Maintenance
Manual.
When either travel control handle is moved from off, an input
signal is sent to node-1 controller. Node-5 controller sends a
24 volt signal to enable the swing/travel alarm. When travel
control handle is moved to off, node-5 controller sends a 0
volt signal to disable the swing/travel alarm.
Travel Brakes
Hydraulic pressure required for releasing the travel brakes is
from high pressure accessory pump system through a
pressure reducing valve at 500 psi (34 bar). For travel brake
operation the system pressure must be above 200 psi (14
bar) for travel brakes to fully release from each travel motor
shaft. If system pressure is below 200-psi (14 bar), travel
brake could be partially applied and damage the brake. If
brake pressure or electrical power is lost when operating, the
travel brake is applied.
When travel brake switch is in on - park position, right and left
travel brakes are applied to hold crane in position. Travel
brake solenoid valve HS-35 is open to allow hydraulic flow
from the brake to tank.
When travel brake switch is in off - park position, an input
signal is sent to node-1 controller. Travel system circuit is
active, waiting for a travel control handle command. When
travel control handle is moved node-7 controller sends a 24
volt output to enable travel brake solenoid valve HS-35.
Brake solenoid valve shifts to block tank port and supplies
hydraulic charge pressure fluid from pump to hydraulically
release all four crawler brakes. If brake pressure or electrical
power is lost when operating, brakes apply.
Travel Forward and Reverse
Both travel closed-loop systems operate the same, except
fluid flow to motor ports is different to each track.
When a travel control handle is moved in
forward
direction,
an input voltage of 2.6 or more volts is sent to node-1
controller. Node-3 and/or node-5 controller sends a variable
zero to 24 volt output that is divided by a resistor and applied
to selected travel pump EDC. Travel brake solenoid valve
HS-35 is enabled to release both left and right crawler
brakes, before selected travel pump(s) strokes.
Travel pump EDC tilts pump swashplate in the
forward
direction. Hydraulic fluid flow is from pump ports of selected
travel pump through swivel to selected motor ports. Node-3
and/or node-5 controller input voltage to selected travel
pump EDC is relative to selected control handle movement.
When a travel control handle is moved in
reverse
direction,
an input voltage of 2.4 volts or less is sent to node-1
controller. Node-3 and/or node-5 controller sends a variable
zero to 24 volt output that is divided by a resistor and applied
to selected travel pump EDC. Node-7 controller sends a 24
volt output to enable travel brake solenoid valve HS-35.
Travel brake solenoid valve is enabled to release both left
and right crawler brakes, before selected travel pump
strokes.
The travel pump EDC tilts the motor swashplate in the
reverse direction. Hydraulic fluid flow is from pump ports of
selected travel pump through swivel to selected motor ports.
Node-3 and/or node-5 controller input voltage to selected
travel pump EDC is relative to selected control handle
movement.
Travel motors are variable displacement and shift internally
with an adjustable spring in each motor P/C (Pressure/
Compensator) valve, preset at 3,915 psi (270 bar). Travel
motors are in minimum displacement (low torque, high-
speed) position when starting. When crawler begins to
move, a high system pressure shifts the PCOR (Pressure
Compensated Over-Ride) spool placing travel motor in
maximum displacement (high torque, low speed) position for
breakaway torque.
Summary of Contents for 18000
Page 1: ...R e f e r e n c e O n l y Service Maintenance Manual Manitowoc 18000 ...
Page 2: ...R e f e r e n c e O n l y ...
Page 4: ...R e f e r e n c e O n l y THE ORIGINAL LANGUAGE OF THIS PUBLICATION IS ENGLISH ...
Page 210: ...R e f e r e n c e O n l y NOTES SKETCHES AND PHOTOGRAPHS ...
Page 315: ...R e f e r e n c e O n l y ...
Page 316: ...R e f e r e n c e O n l y ...