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Honda VTX 1300 & 1800 Cruiser
Champion Honda VTX proprietary differential is a custom-built, left-hand
component of the rear end...as opposed to the way at least a few of our
competitors handle the VTX drive-train, by simply turning their
"regular" differential upside down.
The key advantages
to Champion's approach are:
1) Champion's proprietary pinion gear
drives the ring on the pressure face (rather than on the coasting face
as in an upside down differential) of the ring gear teeth, as dictated
by conventional differential gear design;
2) Champion's proprietary
arrangement keeps the two pinion shaft bearings partially submerged in
lubricating oil as dictated by conventional differential design, when
the oil level is properly maintained. This may not always be the case in
an upside down differential;
The third Champion
advantage requires a bit of a tutorial on differential lubrication
strategy:
A. In differential design, there is
an oil "supply channel" cast into the upper portion of the casing which
accepts oil "slung" up and forward by the ring gear and drains it into
the cavity between the two pinion shaft bearings. This provides
approximately equal amounts of oil to the two pinion shaft bearings;
B. Oil which lubricates
the rear bearing returns directly to the differential "sump";
C.
Oil which lubricates the forward
bearing passes through the bearing into the cavity between that
bearing and the pinion seal and is returned to the differential sump
through a smaller (than the supply channel) "return channel" which is
cast into the lower portion of the casing;
D.
In an upside down differential, in which
the "sump" is above the pinion/ring gear interface, the ring gear will
sling oil up and forward into the return channel. IF that pumping action
is sufficient to move oil "backwards" through the return channel it will
discharge the oil into the cavity between the forward pinion shaft
bearing and the pinion seal. Since there is no return path from this
cavity to the sump, this could over-pressurize the pinion seal. This
arrangement could also leave the rear pinion shaft bearing without
an adequate supply of oil.
E. In short, the third significant
advantage of Champion's custom-built left-hand drive VTX differential is
that it preserves the the proven gear lubrication strategy
in conventional differential design and avoids the potential lubrication
challenges associated with the upside down rear end approach taken by
some other VTX trike manufacturers. |