Maintenance Of Oil Pump - Hitachi NEXT Series Service Manual

Oil-free screw compressor
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4.15 Maintenance of Oil Pump

4.15.1 Removal from the Gear Case
Remove the oil piping from the oil pump. Then, detach
the oil pump from the gear case. (When detaching the
oil pump, be careful not to damage the gear.)
Oil Piping
4.15.2 Disassembling
① Before disassembly, mark the matching positions on
the oil pump body and the bearing housing.
② Remove the gear support attached to the oil pump
③ Pull out the oil pump gear using the gear removing
tool shown in Fig. 3, and then remove the key.
Gear Support
(Removing procedure)
Fix the oil pump gear and
the gear removing tool with
M6 bolts, and remove the
gear using the axial force
of M10 bolt.
④ Loosen the bolts, and remove the bearing housing,
O-ring, outer rotor, inner rotor, and inner key in this
⑤ Remove the snap ring.
Oil Pump
Gear Case
Oil Pump body
Oil Pump Gear
Support Bolt, gear
M10 Bolt
M6 Bolt (2 places)
Confidential to Customer
Outer Rotor
Inner Rotor
Inner Key
Oil Pump body
⑥ Hit the rotor-side end of shaft with a plastic or
wooden hammer; do not use a steel hammer. Thus,
the assembly of shaft, bearings and oil seal can be
Oil Seal
⑦ Place the removed assembly in a vice vertically; its
rotor-side end must be downwards. Hit the shaft
with a plastic or wooden hammer to remove the
Ball Bearing
⑧ Remove the bush bearing from the bearing housing.
(Removing procedure)
Slide the hammer body to hit it strongly against the grip so
that the bearing will be removed by the impact.
Bush Bearing
Snap Ring
Bush Bearing
Bearing Puller Set
Hammer Body

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