Hitachi ZW180 Technical Manual page 355

Traveling Straight with the Same Resistances to
Left and Right Tires
In case resistances to the left and right tires are the
same, distances 'a' and 'b' from the differential pinion
gear center to the respective contact points of the left
and right side gears are the same. Therefore, as
the differential pinion gear and the left and right side
gears solidly rotate forward, the driving forces of the
left and right tires become the same.
Traveling on Soft Ground (Different Resistances
to Left and Right Tires)
In traveling on soft ground, if the left tire slips, the
side gear on the left tire receiving little resistance
tends to rotate more forward than the right side gear.
This rotation causes deviation of the contact points of
the differential pinion gear and the left and right side
gears in the torque proportioning differential.
In case the left side gear rotates slightly more for-
ward than the right side gear, distance 'a' of the con-
tact point of the differential pinion gear and the left
side gear is lengthened. Correlation of the forces at
this time is as follows. a×TA (force applied to the left
side gear) = b×TB (force applied to the right side
gear).
Until the difference of the ground resistances ex-
ceeds certain value, the differential pinion gear does
not roate, and the left and right side gears rotate at
the same speed solidly. As the left tire does not rotate
reduntantly, it does not slip. (Right tire can have drive
force larger than the left tire.) Therefore, tire lives are
prolonged and working efficiency is improved.
COMPONENT OPERATION / Axle
T3-10-7
Left Side Gear
Left Side Gear
Differential
Pinion Gear
Right Side Gear
T487-03-06-016
Differential
Pinion Gear
Right Side Gear
T487-03-06-017