Mitsubishi Fuso CANTER FE85DE6SLGP, Руководство по ремонту

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8. Balance Shafts
• The balance shaft RH and balance shaft LH are mounted in the upper crankcase on the right and left sides of the
crankshaft. The balance shafts reduce the vibration of the engine caused by the rotation of the crankshaft.
• The balance shaft RH and balance shaft LH are both driven by timing gears. Each balance shaft is held in the up-
per crankcase by way of three balance shaft bushings.
• The balance shaft LH has a locating hole to enable correct installation.
8.1 Reduction of vertical vibration
(secondary vibration element)
• When the piston moves up and down,
vertical vibrations are generated at the
top dead center (TDC) and bottom
dead center (BDC) due to inertia.
• The balance shaft LH and the balance
shaft RH rotate so that their weight
portions are at the bottom positions
when a piston is at TDC and at the top
positions when the piston is at BDC,
i.e., the weight portions are always on
the opposite side to the piston head.
• This creates centrifugal forces in the
balance shaft RH and balance shaft
LH, the total of which is equal in
amount to the inertia force that the pis-
ton creates when it is at TDC or BDC.
These centrifugal forces in the bal-
ance shafts cancel out the inertia forc-
es resulting from piston’s movements
and reduce the amount of vertical vi-
bration.
• The balance shafts also reduce the
moment created around the crank-
shaft (which constitutes secondary vi-
bration elements) when the engine is
running in the middle-to-high speed
range.
STRUCTURE AND OPERATION