Manitowoc Grove YB5515-2, Руководство по обслуживанию и ремонту

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GROVE
Published 1-20-2017, Control# 483-02
4-9
CD5515-2/YB5515-2 SERVICE MANUAL HYDRAULIC SYSTEM
4
function regardless of differences in their load and
regardless of the pump flow. The flow relationships specified
between functions are maintained over the full range of the
pump.
Figure 4-2 illustrates the interrelationship of the load sense
shuttle (1), the compensator (2), the directional spool or
variable orifice (3), combined with the variable displacement
load sense pump (4).
After the spool is activated the work port load pressure is
transmitted to the bridge (5). The load sense shuttle (1), in
turn, transmits the highest work port pressure to the load
sense port of the pump (4) and all compensators (2) within
the valve assembly. Pump (4) responds to the load sense
signal with load sense pressure plus pump margin or
differential pressure. It is this margin or differential pressure
that overcomes the compensators (2) and permits flow to
bridge (5) and work port A (16) or B (17). This system
establishes a constant pressure differential across a variable
orifice spool (3). At full stroke of spool (3) the maximum
orifice can be determined, thus creating spool flow ranges
(i.e. 76, 114, 151 Lpm [20, 30, 40 gpm]) at a predetermined
p r e s s u r e d i ff e r e n t i a l a t s p o o l ( 3 ) . I t i s t h e w o r k i n g
combination of the components that sets up the flow dividing
principle.
Inlet Section
The inlet section (Figure 4-2) is connected to the pressure
side of the variable displacement load sense pump by a
hydraulic hose. There is a load sense relief valve installed in
the inlet section.
Working Valve Sections
There are four working sections (Figure 4-2) of the main
control valve that receive hydraulic oil from the variable
displacement load sense pump. These sections control the
hoist, telescope, lift and swing functions. They are closed-
center sections, blocking any return of oil back to tank until
the valve spool is actuated to operate a function. Flow is then
directed through the return core (14, Figure 4-2) to the outlet
port of the inlet/outlet section and then to tank.
HYDRAULIC SWIVEL
General
The hydraulic swivel is at the center of rotation of the mast.
The purpose of the hydraulic swivel is to permit the flow of oil
between the hydraulic components on mast and boom and
the components on the lower structure during any rotation of
the mast.
The hydraulic swivel has seven passages Figure 4-3.
Grooves and ports in the shaft align with ports in the housing.
Seals between the grooves of the shaft prevent leakage
between the passages. The seals fit tightly against the
FIGURE 4-2
Item Description Item Description
1 Load Sense Shuttle 14 Return Core (To Tank/Outlet)
2 Compensator 15 Bias Spring
3 Spool 16 Work Port A
4 Pump 17 Work Port B
5 Work Port Feeder Core (Bridge) 21 Section Load Sense Line
8 Pump Supply (Form Inlet Port) 22 Load Sense & Compensator Signal
Line
9 Pump Supply After Spool to
Compensator 23 Load Sense Shuttle Signal Line
From Work Port Feeder Core
(Bridge)
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Reference Only