Kubota M108S, Workshop Manual

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10-M3
M108S, WSM CABIN
[2] COMPRESSOR
The vane type compressor installed on this cabin is
composed of a cylinder (1) with an oval cross section and
a rotor (2) with five vanes (3). The vane type compressor
is provided with two suction ports and two discharge
ports respectively.
The five vanes (3) mounted on the rotor (2), rotating
along the inner wall of the cylinder (1), keeps air-
tightness using the centrifugal force of the rotor (2) and
the back pressure of the vanes (3) that grow in proportion
to the rotating speed of the rotor (2).
As a result, the volumes of the five cylinder chambers
separated with the cylinder (1) and the five vanes (3)
change.
For each rotation of the rotor (2), each of the cylinder
chambers performs two cycles of inhalation,
compression, and discharge.
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Operation
In proportion to the rotation of the rotor (3), a volume
of a cylinder chamber separated with the cylinder (1) and
the vanes (4) increases. The cylinder chamber inhales
refrigerant gas from the suction port (2).
As the rotor (3) rotates further, a volume of the
cylinder chamber separated with the cylinder (1) and the
vanes (4) decreases, and the refrigerant gas is
compressed. As the rotor (3) rotates even further, the
refrigerant gas is highly compressed and then presses
the discharge valve to open. The refrigerant gas is
discharged from the discharge port (5).
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Compressor Oil
The compressor oil dissolves in the refrigerant, circulates through the air-conditioning cycle, and functions to
lubricate the compressor. But the conventional compressor oil for R12 does not dissolve in R134a, so it does not
circulate through the cycle, and the lifespan of the compressor is considerably shortened.
It is still essential to ensure that the correct refrigerant oil is used. R12 systems were lubricated with mineral oil,
which is totally unsuitable for R134a systems. The letter require PAG oil, which mixes very well with the refrigerant
and provides ideal lubrication throughout the system.
*PAG : Polyalkyleneglycol (Synthetic oil)
(1) Cylinder
(2) Rotor (3) Vane
(1) Cylinder
(2) Suction Port
(3) Rotor
(4) Vane
(5) Discharge Port (A) Compression Process
(B) Discharge Process
(C) Suction Process
Quantity (Total) Brand Name
100 to 120 cc
0.106 to 0.127 U.S.qts.
0.088 to 0.106 Imp.qts.
ND-OIL 8 <PAG* oil>
KiSC issued 06, 2007 A