Drive System Description - Cub Cadet 6X4 Shop Handbook

5.

DRIVE SYSTEM DESCRIPTION

• A belt-type CVT (Continuously Variable Trans-
mission) system carries power from the engine
crankshaft to the transfer case.
See Figure 1.10.
CVT belt
Figure 1.10
• The CVT range provides strong torque and
acceleration, limiting speed to 25 MPH (40
KPH).
• The driving clutch on the engine crankshaft uses
centrifugal force to operate a mechanism that
pulls the sheaves closer together.
The faster the engine spins, the closer the
sheaves get.
As the sheaves close-down on the belt, the belt
is forced outward.
As the belt is forced outward, the drive ratio
decreases so that fewer crankshaft revolutions
equate to more input shaft revolutions at the
input shaft of the transfer case.
NOTE: A lower numeric ratio results is fre-
quently referred to as a "steeper" or "taller" drive
ratio, yielding in increased top speed.
• As the effective diameter of the driving pulley
increases, the belt has less available length to
reach the driven pulley.
The sheaves of the driven pulley is spring-
loaded so that it can absorb the additional ten-
sion.
An additional effect is that the belt is drawn
deeper into the sheaves, reducing the effective
diameter of the driven pulley.
Reducing the diameter of the driven pulley fur-
ther reduces the drive ratio.
CVT driven
element
CVT driving element
• The transfer case is mounted adjacent to the
engine, with the input shaft running fore-and-aft
in the frame. See Figure 1.11.
Transfer
case
• The transfer case contains two forward ratios,
neutral, and reveres.
• Gear selection is controlled by rods and a selec-
tor lever sourced from Hurst®.
Drive shafts with Hooke/Spicer type universal joints
extend fore and aft from the output shafts of the trans-
fer case to drive the front and rear differentials.
The rear differential has a cast iron housing and a
cable-actuated locking feature. See Figure 1.12.
Differential lock
actuator
Rear differential
5
Chapter 1: Introduction
Figure 1.11
Figure 1.12