Toro Workman MD, Service Manual

Page: 59 / 210

Rev. A
Workman MD/MDX Drive Train Page 5 -- 5
Driven Clutch Operation
The operation of the driven clutch is affected by trans-
axle load. When the vehicle is stopped, the drive belt is
held at the outer diameter of the driven clutch sheaves
from the pressure of the spring pushing the moveable
sheave against the fixed sheave and away from the
fixed cam.
Once the drive belt starts rotating, the driven clutch also
starts to rotate. With increasing speed of the drive
clutch, the drive belt begins to climb to the outer diame-
ter of the drive clutch sheaves. This increases the ten-
sion on the drive belt, and forces the moveable sheave
of the driven clutch to move away from the fixed sheave
against the pressure of the spring. As the belt tightens
and the sheaves open up, the drive belt rides lower in the
driven clutch sheaves.
With increased load to the transaxle, the fixed cam re-
sists forward movement relative to the moveable
sheave and drive belt. Torque from the drive belt and
spring pressure moves the moveable sheave up the
ramp of the fixed cam. The drive belt becomes posi-
tioned closer to the outer diameter of the driven clutch
sheaves.
On vehicles with a serial number below 310000000,
three (3) sets of buttons on the driven clutch moveable
sheave provide a low friction surface on which the move-
able sheave can slide on the ramp of the fixed cam (Fig.
4).
On vehicles with a serial number above 310000000, a
fixed cam on the driven clutch moveable sheave rotates
on a pair of rollers in the fixed sheave base to allow low
friction movement of the moveable sheave (Fig. 5).
1. Moveable sheave
2. Ramp (fixed cam)
3. Button
4. Fixed sheave
5. Spring
Figure 4
2
1
4
3
5
1. Moveable sheave
2. Fixed sheave
3. Spring
Figure 5
2
1
3
Drive
Train