Kubota D1803-CR-E4, Workshop Manual

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2.10.3 Function of connecting rod
The connecting rod connects the piston and crankshaft
and transfers the combustion pressure received by the
piston to the crankshaft.
The part that connects to the crankshaft is called the
big end and the part that connects to the piston pin is
called the small end.
The big end is provided with bearing metal.
The small end is provided with a bushing.
Oil is supplied between it and the shafts at both ends to
reduce friction resistance and enable smooth rotation.
2.11 Crankshaft
2.11.1 Outline of crankshaft
The crankshaft converts the reciprocating motion
obtained from combustion to rotational motion via the
connecting rod.
2.11.2 Structure of crankshaft
The crankshaft is formed with the crank arms and
crankpins integrated.
(1) Crank arm
(2) Crankpin (3) Crank journal
(4) Balance weight
2.11.3 Function of crankshaft
The crankshaft converts the reciprocating motion
obtained from combustion to rotational motion via the
connecting rod.
The part of the shaft supported in the main bearing
case and that rotates is called the crank journal, the
part connected to the connecting rod is called a
crankpin, and the part that connects both of these is
called the crank arm.
While conducting continuous power to outside the
engine, this also causes each of the intake,
compression, combustion, and exhaust strokes to be
performed.
2.11.4 Specification of crankshaft
Crankpin (Undersize)
0.20 mm
0.0079 in.
0.40 mm
0.016 in.
Crankshaft journal (Undersize)
0.20 mm
0.0079 in.
0.40 mm
0.016 in.
2.12 Main bearing case
2.12.1 Outline of main bearing case
The main bearing case is a bearing that supports the
crankshaft.
2.12.2 Structure of main bearing case
The main bearing case is holds the crankshaft.
(1) Main bearing case
(2) Screw (3) Bearing metal
2.12.3 Function of main bearing case
The main bearing case supports the crankshaft and
also fulfills the role as a passage for supplying oil to the
crankshaft.
The main bearing case is provided with bearing metal.
Oil is supplied between this metal and the crankshaft to
reduce friction resistance and enable smooth rotation.
4. ENGINE
MECHANISM
2. Engine body
4-8
D1803-CR-E4,D1803-CR-TE4,D1803-CR-TIE4,V2403-CR-E4,V2403-CR-TE4,V2403-CR-TE4BG,V2403-CR-TIE4
KiSC issued 12, 2018 A