Figure 29-15. Double-Reduction Dual-Ratio Drive Axle.
jackshaft through a spiral-bevel drive gear. Two helical
dual front wheels are used in addition to dual rear
pinions of different sizes and a two-way dog clutch are
wheels, a greater portion of the total load can be carried
mounted on the jackshaft. The two helical pinions are
by the front axle. This makes a greater payload possible
not fast to the jackshaft but rotate freely on it on
without increasing the overall length of the vehicle.
bearings. They are in constant mesh with two helical
Interwheel differentials also can be used for front dead
gears of correspondingly different sizes, both mounted
axles, live rear axles, tandem rear live axles, and trailer
rigidly on the differential case. The sliding dog clutch Is
dead axles to provide for the difference In distance
controlled by a hand lever and clutches either one of the
traveled by each of the pair of dual wheels in rounding
helical pinions fast to the jackshaft. The drive is from the
curves, and for the different rolling radius of each of the
propeller shaft to the drive pinion, to the bevel drive gear,
dual wheels caused by the crown of the road or ruts. It is
to the Jackshaft, to the right helical pinion, to the right
thought that a great saving In tire wear results because
helical gear, to the differential case, to the differential
of the elimination of the slippage that occurs when dual
pinions, to the differential side gears, to the axle shafts,
wheels are bolted together rigidly.
and then to the wheels. When the dog clutch is In the
Power Dlvlder(Fig. 29-16).
high-speed position (moved to the left), the drive Is the
same, except that It is through the other pair of helical
(1) The forward rear axle is of the full-floating,
double-reduction type having a spiral-bevel pinion and
/. Interwheel DIfferential.
One of the latest
gear for the first reduction, and a spur pinion and gear for
developments In front-wheel drives is dual wheels having
the second reduction. The spiral-bevel pinion is driven
an Interwheel differential that makes them easily
through a power divider, which also drives the rearward
steerable. Each wheel is equipped with Its own brake.
rear axle through a shaft that passes through the pinion
Vertical steering knuckle pivots are used.
differential is of the spur gear type, the pinions having a
tooth form that gives It the same action as the high-
traction differential described In paragraph 29-3. When