OC60-E2, OC95-E2, WSM
ENGINE
M-5
[3] OIL PUMP
The oil pump in this engine is a trochoid pump.
Inside the pump body, the 4 lobe inner rotor (3) is
eccentrically engaged with the 5 lobe outer rotor (4).
The inner rotor (3) is driven by the governor gear shaft
via gears, which in turn rotate the outer rotor (4).
When the inner rotor (3) rotates, the outer rotor (4)
also rotates in the same direction.
The two rotors have differences in lobe number and
center, which generates space between lobes as shown
in the figure.
At position (A), there is little space between lobes in
the inlet port (1). As the rotor rotates towards position
(B), the space between the lobes becomes larger,
creating a negative pressure which sucks in oil.
Outside the inlet port (1), as shown in position (C), the
space between the lobes becomes gradually smaller,
and oil pressure increases. At position (D), oil is
discharged from the outlet port.
[4] OIL PRESSURE SWITCH
The oil pressure switch is mounted on the side cover,
to warn the operator that the lubricating oil pressure is
poor.
If the oil pressure falls below 49 kPa (0.5
, 7
psi), the oil warning lamp will light up, warning the
operator. In this case, stop the engine immediately and
check the cause of pressure drop.
(1)
Inlet Port
(3)
Inner Rotor
(2)
Outlet Port
(4)
Outer Rotor
0000009139E
(1)
Terminal
[A]
At Oil Pressures of
(2)
Insulator
49 kPa (0.5
,
(3)
Spring
7 psi) or Less
(4)
Diaphragm
[B]
At Proper Oil Pressure
(5)
Contact Rivet
(6)
Contact
(7)
Oil Switch Body
0000009142E
