
ASSEMBLY OF MOTOR AND PUMP UNIT
Low noise bell-housing will help to attenuate the transmission of vibrations and the emission of noise generated by the system.
Self-evidently, however, the mere adoption of a low noise bell-housing will achieve little unless the motor and pump are correctly installed on the machine
or on the tank of the hydraulic power unit.
Should be followed in order to achieve best possible results and correct installation:
1
MOTOR AND PUMP UNIT MOUNTED
HORIZONTALLY ON OIL TANK LID
- The suction pipe attached to the pump must be rigid and tted using a resilient
bulkhead flange of the FTA series, which helps to cushion the vibrations
propagated between the pipe and the tank lid.
If pipes need to be bent, the radius of curvature must be at least 3 times the
pipe diameter.
Do not use elbow ttings, as these will signicantly increase pressure losses.
- The pressure pipeline of the pump must be flexible and long enough to
include bends with the minimum radius of curvature recommended by the
manufacturer for the specied operating pressure.
- The return pipeline running from the service to the lter must be exible.
Where oil is returned directly to the tank of the hydraulic power unit through
a rigid pipe, it is advisable to use a resilient bulkhead ange of the FTR series,
which helps to cushion the vibrations propagated between the pipe and
the tank lid.
- Anti-vibration devices (resilient mounts or damping rods) must be located
under the feet of the electric motor or the PDM foot brackets, depending on
the mounting position of the motor.
- The lids of hydraulic oil tanks must be sturdy enough to support the load
they carry.
2
MOTOR AND PUMP UNIT MOUNTED
HORIZONTALLY ON MACHINE
- As a matter of good practice, the oil tank and motor-pump unit should be
mounted on a single supporting frame of strength sufcient to support the load.
- If the hydraulic system is tted with a side-mounted lter, the suction pipeline
to the pump must be flexible and long enough to include bends with the
minimum radius of curvature recommended by the manufacturer.
- If the suction filter is not side mounted, the pipeline should be rigid and
installed in conjunction with a compensating coupling.
- The pressure pipeline of the pump must be exible, and long enough to include
bends with the minimum radius of curvature recommended by the manufacturer
for the specied operating pressure.
- The return pipeline running from the service to the lter must be exible.
Where oil is returned directly to the tank of the hydraulic power unit through
a rigid pipe, it is advisable to use a resilient bulkhead ange of the FTR series,
which helps to cushion the vibrations propagated between the pipe
and the tank lid.
- Anti-vibration devices (resilient mounts or damping rods) must be located
under the feet of the electric motor or the PDM foot brackets, depending
on the mounting position of the motor.
FINAL CONSIDERATION
For best results, in any event, the motor-and-pump unit should be incorporated into the hydraulic system in such a way that no one component is rigidly associated
with another, resulting in the propagation of vibration, and consequently noise.
RECOMMENDED TIGHTENING TORQUES FOR MOTOR/PUMP FIXING ON THE BELL-HOUSING
M6
M8
M10
M12
M14
M16
M18
M20
M22
M24
10 N∙m
15 N∙m
50 N∙m
84 N∙m
135 N∙m
205 N∙m
280 N∙m
400 N∙m
530 N∙m
690 N∙m
Note: The above guidelines are indicative only and subordinate to the solutions adopted ultimately by design engineers.
Bell-Housing
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