TRUCK SERVICE MANUAL
The basic functions having been designated, let's
To transmit required loads, the driveshaft must
possess high strength. Forged steel, or high strength cast
yokes are generally used to provide necessary strength and
the rigidity required to maintain bearing alignment under
torque loads and during high speed operation. Special high-
strength tubing is used to provide maximum torque carrying
capacity at minimum practical weight. This tubing must be
securely welded to its end members, to provide the necessary
High quality anti-friction bearings are used to
withstand required loads while oscillating at high speeds.
These bearings on the journal cross carry vary high loads for
their size. The full complement, roller-type (needle) bearings
are generally used because of their high capacity in a limited
space. Bearings are individually sealed to provide retention of
required lubricants as well as to prevent the entry of foreign
material. If lubricants become contaminated with water or
abrasive material, needle bearing life is seriously affected.
Abrasive material is a major problem where a vehicle
operates under conditions of extreme moisture and dirt. Off-
highway installations are especially critical in this respect.
Military trucks represent the extreme in this direction and were
the first to show the shortcomings in the conventional cork
seals used in universal joint bearings. It was found that an
improved seal was required for this type of operation.
Synthetic rubber-type seals were developed for these
installations. These seals have been in use for many years on
military vehicles and are now used in most commercial
installations. The improved sealing shows increased life and
a less critical re-lubrication cycle.
The sliding splines between slip joint and permanent
joint must support the driveshaft and be capable of sliding
under full torque loads. To provide adequate strength and
wear resistance, hardened and ground splines are used.
These splines are phosphate coated to resist galling and to
reduce sliding friction.
CTS-2730 Page 5
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