MOTOR TRUCK SERVICE MANUAL
AXLES-REAR I
the spider clutch teeth and the corresponding cams (see Fig.
5).
The driving clutch teeth of the spider transmit the driving force
to the driven clutchmember, which in turn drives the right hand
(inside) wheel constantly at ring gear speed, thus propelling
the vehicle. The left hand (outside) wheel covers a greater arc
than the right hand (inside) wheel and driven by the traction of
the road, must turn faster than ring gear speed. Likewise, the
left hand driven clutch member must turn faster than the
spider. In other words, it permits differences in wheel speeds
or differential action. Fig.
6 illustrates how this is
accomplished.
The right hand row of cams on the center cam member are
meshed securely with the cams on the right hand driven clutch
member. With the center cam thus locked in this position so
that it cannot rotate with respect to the spider, its came on the
Fig. 4 Straight Forward Driving
left hand side serve as ramps upon which the mating cams on
the left hand driven clutch member can rise enabling that
shifts the driving force to the opposite set of driving faces on
driven clutch member to disengage from the spider. The
the mating clutch teeth. Again we have the assembly
ramps on the center cam are high enough to permit the clutch
operating as a unit with each wheel being forced to rotate at
teeth on the driven clutch member to clear the teeth on the
ring gear speed.
spider and when the crest of the ramp is passed, the teeth of
the driven clutch member are forced back by spring pressure
Right Hand Turn--Forward Direction
into full engagement with the clutch teeth of the spider.
When making a turn, differential action is required in order to
permit the outside wheel to travel a greater distance, and
faster, than the inside wheel.
Fig. 6 Forward Right Hand Turn
(Cross Sectional View)
This engagement and disengagement or indexing operation
continues throughout the turn with a rapidity that is in direct
Fig. 5 Right Hand Turn--Forward Direction
relation to the speed of the overrunning wheel.
A conventional bevel gear type differential permits the outside
As the vehicle completes the turn and is again driven in a
wheel to turn faster than ring gear speed while the inside
straight forward direction, differential action no longer being
wheel turns slower than ring gear speed. The NoSPIN
required, both driven clutch members become fully engaged
differential allows either wheel to turn faster than the ring gear
with the clutch teeth of the spider, then the operation, as
speed but does not permit either wheel to turn slower than the
described in "Straight Forward Driving" is resumed
ring gear speed when power is applied.
.
When negotiating a right hand turn in a forward direction, the
right hand driven clutch member remains fully engaged with
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