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The cylinder does not work
The cylinder works but
not properly
SOLUTION OF THE ABOVE PROBLEMS
Note: See also drawing at pages 28-29-30.
This is the most serious damage thet can occur to the cylinder;
1
it means that the rotating part of the hydraulic manifold (body) is
jammed in the fixed part (manifold ring). This situation occurs when
the oil in the cylinder is not perfectly clean or has some metallic
particles or foreign parts inside and can be caused when:
- The oil fliters are insufficient of damaged
- The circuit and the hydraulic tubes are not perfeclty clean.
For other possible reasons, please see pos. 2 to 5; for possible solu-
tions, please see pos. 6 and 7.
Use of improper oil. An oil with too high a viscosity causes alocalited
2
high heating, when working at high speed with cold oil. It can also
cause overheating in normal conditions.
3
The cylinder has been rotated without oil pressure.
The fittings used have conical or too long threads, that cause the
4
deformation of the manifold ring.
The oil feeding or the oil drain tubes or the stop fork heve been
5
mounted in such a way to apply an axial stress on the manifold ring,
damaging the bearings.
If there is only a slight seizure, it is recommended to disassemble the
6
manifold ring, remove the seizure by an abrasive stone and replace
the bearings. Carefully clean before reassembling.
If the seizure is more serious, it becomes very difficult to dismantle
7
and repair the cylinder. In this case, it is recommended to send the
cylinder to one of the "Autoblok " Service Centers, for the repair or
the replacement of the cylinder.
8
Check that there is no alarm signal in the operation system of the
machine that could hinder the operation of the controls. Carefully
check the electric circuit and the buttons.
9
Check to the hydraulic circuit controlling the cylinder stroke is in
good working conditions and gives the requested pressure; check
the following:
A)
the oil level in the tank
B)
the proper working of the pump
C)
the filters must not be clogged
D)
the solenoid valves must not be jammed
E)
the tubes must be properly connected.
10
Be careful not to reduce the pressure to 1/3 (or less) in one move, as
regards to the starting pressure: this would prevent the working of
the safety valves, hence, the piston stroke.
It is recommended to reduce the pressure gradually, making every
time a movement of opening / closing.
11
One of the two safety valves jammed into its seat, due to different
reasons (dirty oil, overpressure, water hammering, changes in
10
TROUBLE SHOOTING GUIDE FOR SIN- CYLINDER
The r otating part is jammed
to the xed manifold
The cylinder piston is jammed and
does not make the axial stroke
The cylinder leaks from the front and/or rear side of the
manifold ring (between the xed and rotanting part
The cylinder leaks between the body and/or the
front cover and the piston rod (front or rear side)
The cylinder makes the axial stroke, but moves too slowly
The cylinder does not make the whole axial stroke
The temperature in the cylinder has reached 70 °C
There is a noise when the cylinder makes an axial stroke
The cylinder is noisy when rotating
Vibrations during rotation
temperature, wear of the internal components of the valves).
Keeping the power unit without pressure, carefully unscrew the 2
drain screws A and B (see page 28-29-30). Be careful that one of the
cylinder chambers is still under pressure. By loosing these screws, a
certain quantity of oil willl come out from one of them, resetting the
valve control. Reassemble and tighten the screws, then, operate the
cylinder. If the piston does still not move, it is necessary to change 1
or 2 safety valves (see instructions).
12
Check that the draw tube for the connection to the chuck is not too
long (or too short), causing a mechanical axial stop, hindering the
piston stroke.
13
The oil seal between the front and rear parts of the oil manifold is
made by means of rotating rubber seals (see drawing page 28-29-30).
A)
If the leakage is in the rear is it is only necessary to remove the rear
cover 6B and change the rear seal 37B.
B)
If the leakage from the front, it is necesary to dismantle the complete
oil manifold group and change the front seal 37B. In this case our
suggestion is to also change the rear seal and the bearings 46B and
47B which could have been damaged during the dismanlting opera-
tions.
If the leakage is in the front side between the body 1 and the piston
14
rod 3A it is necessary to change the rubber seal 26.
If the leakage is in the rear, between the distribution flange 2 and the
piston rod 3A, it is necessary to change the rubber seal 25.
15
Let's suppose that the machine tool manufacturer dimensioned the
power unit considering the real needs of oil capacity. If the power
unit is well dimensioned, there can be two kinds of problems:
- in the hydraulic circuit
- in the cylinder
16
Problems in the hydraulic circuit:
A)
The filters are clogged and do not allow the regular flow of the pump
capacity: in this case, clean the filters and, if necessary, replace
them.
NOTE: Be careful that the delivery filter must be a paper
filter with 10µ aperture size and must be replaced every 6 - 8
months.
B)
The pump is worn and does not guarantee the regular delivery.
Measure the delivery in l/min. and, if it is not enough, replace the
pump.
C)
The solenoid valves do not make the whole stroke and reduce the
room for the oil flow. It can be caused by wear of the valves or by the
entry of dirty oil between the pistons.
17
Problems in the hydraulic cylinder:
To be sure if the problem is in the hydraulic circuit or in the cylinder,
mount 2 gauges in the drain holes A and B, using 2 suitable fittings
(see page 28-29-30).
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5
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24
3
4
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25
26
5
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