| |
TM 10-3930-671-24
SECTION I - CONSTRUCTION AND OPERATION
Figure 1.0
A.
COMPONENTS AND FUNCTIONS
It is necessary to become familiar with the function of the
main components to understand the basic operating
principles of the Roosa Master Model DB2 pump. See
cutaway view (Figure 1.0) for construction details.
MAIN COMPONENTS
1.
Drive Shaft
2.
Housing
3.
Metering Valve
4.
Hydraulic Head Assembly
5.
Transfer Pump Blades
6.
Pressure Regulator Assembly
7.
Distributor Rotor
8.
Internal Cam Ring
9.
Automatic Advance (Optional)
10.
Pumping Plungers
11.
Governor
The main rotating components are the drive shaft (1),
transfer pump blades (5), distributor rotor (7), and
governor (11).
With reference to Figure 1.0, the drive shaft engages the
distributor rotor in the hydraulic head. The drive end of
the DB2 rotor incorporates two pumping plungers.
The
plungers
are
actuated
toward
each
other
simultaneously by an internal cam ring through rollers
and shoes which are carried in slots at the drive end of
the rotor. The number of cam lobes normally equals the
number of engine cylinders.
The transfer pump at the rear of the rotor is of the
positive-displacement, vane-type and is enclosed in the
end cap. The end cap also houses the fuel inlet strainer
and transfer pump pressure regulator. The face of the
regulator assembly is compressed against the liner and
distributor rotor and forms an end seal for the transfer
pump. The injection pump is designed so that end thrust
is against the face of the transfer pump pressure
regulator. The distributor rotor incorporates two charging
ports and a single axial bore with one discharge port to
service all head outlets to the injection lines.
The hydraulic head contains the bore in which the rotor
revolves, the metering valve bore, the charging ports and
the head discharge fittings. The high-pressure injection
lines to the nozzles are fastened to these discharge
fittings.
F-214
|
