Disassembly / Reassembly Of Bearings And Shims - Pratissoli KF Serie Manual De Reparación

2.1.4

Disassembly / Reassembly of bearings and shims

The type of bearings (taper roller) ensures the absence of
axial clearance on the bend shaft. The shims are defined to
meet this necessity. For disassembly / reassembly and for any
replacements, carefully observe the following directions:
A) Disassembly / Reassembly of the bend shaft without
replacement of the bearings
After having removed the side covers as indicated in par. 2.1.1,
check the conditions of the rollers and their relative tracks. If
all parts are in good condition, clean the components carefully
with a degreaser and redistribute lubricant oil uniformly.
The previous shims can be reused, taking care to insert them
only under the indicator side cover.
Once the complete unit is mounted (Indicator side flange +
shaft + motor side flange), check that the rotation torque of
the shaft - with the con-rod disconnected - is a minimum 4
Nm, Max 7 Nm.
To transition the two side covers closer to the casing, it is
possible to use 3 M6x40 screws for the first positioning
phase as indicated in Fig. 8 and the screws provided for final
fastening.
Shaft rotation torque (with the con-rod connected) should not
exceed 8 Nm.
B) Disassembly / Reassembly of the bend shaft with
replacement of the bearings
After having removed the side covers as indicated in par. 2.1.1,
remove the outer ring nut of the bearings from the relative
covers and the inner ring nut with the remaining part of the
bearing from the two ends of the shaft by means of a normal
"pin punch" or a similar tool as indicated in Fig. 8 and Fig. 9.
The new bearings can be mounted cold with a press or rocker,
supporting it on the lateral surface of the ring nuts involved
in press fitting with the rings. The press fitting operation can
be facilitated by heating the involved parts to a temperature
between 120°C - 150°C (250°F - 300°F), ensuring that the ring
nuts fit fully into their seats.
Never exchange the parts of the two bearings.
Determining the shim pack:
Perform the operation while the piston/con-rod guide units
are assembled, the con-rod caps are disconnected and the
con-rods are pushed downwards. Insert the pump shaft
without tab into the casing, making sure the PTO shank comes
out of the correct side.
Secure the PTO side flange to the casing, taking care with the
lip seal as described previously and tighten the fixing screws
to the recommended torque.
Then feed the flange on the indicator side without shims in
the carter and start to move it closer, manually screwing the
M6x40 service screws in equally, with small rotations such as
to move the cover in slowly and correctly.
At the same time, check that the shaft rotates freely by turning
it manually.
Continuing the procedure in this way, a sudden increase in
hardness during shaft rotation will soon be experienced.
At this point, halt the forward movement of the cover and
loosen the fixing screws completely.
With the aid of a feeler gauge, measure the clearance between
Fig. 12
the side cover and pump casing (see Fig. 14).
Fig. 12/a
19
Fig. 13
Fig. 14