3 - 2
Brake Valve
During Travel - Brake Released
During travel, pressurised oil is fed into port
A
to open valve
127
and supply oil via port
C
to traction motor
M
. The
pressurised oil also enters chamber
b
through drilling
a
of
spool
123
. The pressure build-up in chamber
b
causes spool
123
to move to the left to connect motor return port
D
to
port
B
.
The result is unrestricted oil flow and, therefore, rotation of
the motor. The movement of spool
123
also allows
pressurised oil to flow through port
P
into piston
112
of the
parking brake, overcoming the parking brake spring to
release the brake pressure.
Travel Stopped - Brake Activated
When travel is de-selected, there is no pressure at port
A
.
Spool
123
is no longer under the influence of pressurised oil
(as described above) and returns to its neutral position under
the influence of the two springs
128
. This spool position
completely shuts off ports
A
and
B
from the motor feed and
return ports
C
and
D
.
The inertia of motor
M
immediately following de-selection of
travel causes a build-up of pressurised oil in port
D
. This
pressurised oil passes through the drilling of valve
201B
into
chamber
f
and thence chamber
g
. The pressure moves
piston
213
up to force oil into chamber
h
. The pressure
build-up in port
D
opens valve
201B
to allow the oil to flow
from port
D
to port
C
to prevent cavitation.
When piston
213
reaches the end of its pressure induced
stroke, the pressure in chamber
f
and
g
increases and the
valve
201B
closes again, allowing a further increase in
pressure in port
D
. This causes valve
201A
to open, passing
the oil in port
D
(at a higher pressure than that of the
machine main relief valve) into port
C
. The pressure in port
D
is thereby controlled in two steps to provide smooth braking
to a standstill.
Section F
Transmission
9803/6410
Section F
3 - 2
Issue 1
Operation
JS01630
JS01640
Summary of Contents for JS130
Page 65: ...Section 3 Section 3 9803 6410 Issue 1 9 1 9 1 Routine Maintenance Component Location Diagram...
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Page 119: ...3 1 Section C Electrics 9803 6410 Section C 3 1 Issue 1 Layout Operator s Cab...
Page 142: ...5 3 Section C Electrics 9803 6410 Section C 5 3 Issue 1 Pump Control FLOW CHART...
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Page 210: ...3 4 Section E Hydraulics 9803 6410 Section E 3 4 Issue 2 Schematics Shuttle Block...
Page 532: ...Contents Page No Technical Data 1 1 i Engine 9803 6410 i Issue 1 Section K Section K...