Drive Clutch Operation - Toro Workman MD Service Manual

Drive Clutch Operation

The operation of the drive clutch is affected by engine
shaft speed. When the engine is off and not turning, the
drive belt rests low within the drive clutch sheaves as the
clutch sheaves are spaced apart. As the engine is
started and increases in speed, the clutch weights move
outward as they spin about the engine drive shaft. The
outward movement of the weights against the spider as-
sembly forces the moveable sheave closer to the fixed
sheave. This inward movement of the moveable sheave
engages the drive belt which begins to rotate.
With increasing engine speed, the moveable sheave
continues to move inward. This sheave movement
forces the drive belt to ride towards the outer diameter
of the drive clutch sheaves which increases the drive
belt speed.
When engine speed is decreased, the weights exert
less force on the moveable sheave. The reduced force
causes the moveable sheave to shift away from the fixed
sheave and slows the drive belt speed. As engine speed
continues to decrease, the drive belt disengages from
the clutch sheaves.
The drive clutch used on vehicles with serial numbers
below 310000000 (Fig. 2) includes three (3) rollers,
three (3) cam weights and a spring to control operation
of the moveable sheave.
The drive clutch used on vehicles with serial numbers
above 310000000 (Fig. 3) controls moveable sheave
operation with six (6) weighted rollers and ramp sur-
faces in the moveable sheave.
Drive Train
1
6
1. Fixed sheave
2. Moveable sheave
3. Spider assembly
4. Cover
1. Fixed sheave
2. Moveable sheave
3. Spider assembly
Rev. A
Page 5 - - 4
2
Figure 2
5. Spring
6. Cam weight (3 used)
7. Roller (3 used)
1
5
2
Figure 3
4. Cover
5. Roller (6 used)
Workman MD/MDX
3
4
5
7
4
3