Pinion Gear Replacement Procedure - Hitachi NEXT Series Service Manual

4.21 Pinion Gear Replacement Procedure

4.21.1 Removing the Air End
Remove the air end.
( see p. 43 "4.17 Oil Pump motor and Airend
removal" 4.17.2 Airend removal)
4.21.2 Pulling Out the Pinion Gear
Attach the pinion gear pull-out tool. When attaching
the tool, ensuring that the O-ring is not stuck. Then
increase the oil pressure slowly and gradually using a
high-pressure pump to check for oil leak.
Shaft
Recommended equipment : SKF Oil injector 226400 series
4.21.3 Shrink-Fitting the Pinion Gear
Shrink-fit the pinion gear. Be sure to fully insert the
component until it comes in contact with the stepped
section of the motor. The temperature of shrink fitting
must be approximately 392℉ (200℃).
(1) O-Ring (2) O-Ring
Pinion Gear
Pull-Out Tool
Confidential to Customer
Air End Shaft Dia.
φ 1.17 inch
1st-stage
( φ 29.8mm)
φ 0.976 inch
2nd-stage
( φ 24.8mm)
Pump connecting port
(PS1/4)
52
Max Oil Pressure
Required
21750 psi
(150MPa)
20300 psi
(140MPa)
To Pump