The limit pressure of relief valve has been set to 12MPa.Therefore,when the stop
The limit pressure of relief valve has been set to 12MPa.Therefore,when the stop
valve is completely closed,the preeure gauge indicates its setting preesure.
valve is completely closed,the preeure gauge indicates its setting preesure.
If
If
the
the
hyd
hyd
rau
rau
lic
lic
pre
pre
ssu
ssu
re
re
exc
exc
eed
eed
s
s
12M
12M
Pa,
Pa,
thi
thi
s
s
ind
ind
ica
ica
tes
tes
tha
tha
t
t
the
the
rel
rel
ief
ief
val
val
ve
ve
mal
mal
fun
fun
cti
cti
ons
ons
.If
.If
the
the
hyd
hyd
rau
rau
lic
lic
pre
pre
ssu
ssu
re
re
is
is
too
too
low
low
,th
,th
is
is
ind
ind
ica
ica
tes
tes
tha
tha
t
t
the
the
oil
oil
pum
pum
p
p
malfunctions or the relief valve spring has been broken.In this case be careful not to keep
malfunctions or the relief valve spring has been broken.In this case be careful not to keep
the stop valve close
the stop valve close
d for more than 15 seconds.
d for more than 15 seconds.
Caution:The pump supplies the hydraulic oil to actuate the power cylinder.Its work
Caution:The pump supplies the hydraulic oil to actuate the power cylinder.Its work
must be considered from two different aspects,namely pressure and flow rate.
must be considered from two different aspects,namely pressure and flow rate.
Pressure is designated to give thrust to the cylinder whereas flow rate relates to the
Pressure is designated to give thrust to the cylinder whereas flow rate relates to the
kinetic speed of the cylinder.
kinetic speed of the cylinder.
Therefore,even when the hydraulic pressure is
Therefore,even when the hydraulic pressure is
normal,say 12MPa,the power steering
normal,say 12MPa,the power steering
cannot work normally if flow rate is insufficient.This results in heavy steering.Since the
cannot work normally if flow rate is insufficient.This results in heavy steering.Since the
flow valve and relief valve have been properly adjusted according to capacity and use
flow valve and relief valve have been properly adjusted according to capacity and use
conditions of the power steering,it is necessary put the match mark in the set position or
conditions of the power steering,it is necessary put the match mark in the set position or
measure the distance to the screw head if disassembly of valve is needed.
measure the distance to the screw head if disassembly of valve is needed.
6.3 Troubleshooting Guide
6.3 Troubleshooting Guide
Possible cause
Possible cause
Flow control valve spool stuck
Flow control valve spool stuck
Flow control valve spool worn
Flow control valve spool worn
Relief valve stuck open
Relief valve stuck open
Relief valve stuck closed
Relief valve stuck closed
Relief valve vibrating
Relief valve vibrating
Relief valve stuck closed
Relief valve stuck closed
Relief valve stuck open
Relief valve stuck open
Flow control valve spool stuck
Flow control valve spool stuck
Flow control valve spool worn
Flow control valve spool worn
Relief valve vibrating
Relief valve vibrating
Flow control valve spool stuck
Flow control valve spool stuck
Flow control valve spool worn
Flow control valve spool worn
Relief valve stuck open
Relief valve stuck open
Flow control valve spool stuck
Flow control valve spool stuck
Flow control valve spool worn
Flow control valve spool worn
Remedy
Remedy
Disassemble,r
Disassemble,r
epair or
epair or
replace
replace
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Disassemble and repair or replace
Disassemble and repair or replace
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Replace as assembly
Disassemble and repair or replace
Disassemble and repair or replace
Replace as assembly
Replace as assembly
Problem
Problem
Steering wheel is caught
Steering wheel is caught
when rapidly turned
when rapidly turned
Oil pressure does not rise
Oil pressure does not rise
Oil pressure higher than
Oil pressure higher than
relief set pressure
relief set pressure
Noisy relief valve
Noisy relief valve
Too high oil temperature
Too high oil temperature
Hard steering operation
Hard steering operation
while idling
while idling
Varying steering force
Varying steering force
Hard steering operation
Hard steering operation
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