Pressure shock
Insufficient
thrust or
lowered
motion speed
Overlarge cushion clearance
Reduce cushion clearance
Bent piston rod results in intense fric�on
Piston rod to be straightened
Oversize or undersize fit clearance
between bore and piston, broken or too
�ght seals result in inner leakage or large
moving resistance
Repair or replace part with wrong size and
accuracy. Seals to be re-assembled,
adjusted or replaced
manufacture errors or poor assembly of
moving parts results in decentra�on or
intense fric�on on one side
Repair parts with errors, or re-assemble
Scratch on bore results in blocked piston, or
poorly processed bore
bore honing, repair or replace cylinder
tube
Contaminated oil by too much foreign
par�cles makes piston or piston rod blocked
Clean hydraulic circuit, and replace
hydraulic oil
One-way valve/thro�le valve to be repaired
Diameter of oil return pipe to be enlarged, turn
down the pressure of back pressure valve
Overlarge pressure in cushion chamber due
to undersized volume
Diameter and length of cushion chamber
to be increased
Too high oil temperature results in more
leakage
Insufficient oil supply of power pack
Power pack to be repaired or replaced
One-way valve/thro�le valve failure in
cushion device
Find out the reason of oil temperature
rising and amend seal structure to lower
down oil temperature
Too high oil return resistance in hydraulic
return line
Too low se�ng pressure or regula�ng
failure of pressure relief valve
Turn up se�ng pressure, or fix pressure
relief valve
Trouble
Possible causes
Solutions
Jerky motion of
piston rod
Aerated oil
Air to be eliminate by exhaust
Inlet oil pipe to be replaced
Piston and rod to be aligned
Serious cylinder leakage
Replace seals or increase pump flow
Overlarge minimum stable flow of flow
valve
Flow valve with small minimum stable flow
to be employed
Flexible hose employed between cylinder
and flow valve
Replaced by nonflexible hose
Fric�onal resistance increases due to
abrasive par�cles in oil
Clean hydraulic elements, and replace
hydraulic oil and filter
Reduce fric�onal resistance by lubrica�on
Fric�onal resistance is too high or changes
due to improper fabrica�on or assembly
of parts with rela�ve mo�on
Poor lubrica�on between surfaces of
moving parts
Poor seals alignment of cylinder piston
and rod
9.2
Hydraulic cylinder
34
AL
2525 &
AL
2625
USER MANUAL
