Operation; Input System; Operation Input System; Speed Reduction System - Toro 20330 - Low Wheel Walk Power Mower Service Manual

OPERATION

Input System:

Power is transferred from the engine to the transmission
by a belt. The self-propel pulley at the engine is keyed
to the crankshaft. The pulley on top of the transmission
is supported by a ball bearing and drives a pinion
gear inside the transmission. Tensioning of the belt is
accomplished by pivoting the transmission. When the
operator squeezes the control bar toward the handle,
a control cable tilts the transmission backward and
tensions the belt. When the control bar is released,
gravity pivots the transmission forward to loosen the belt.
Belt guides at the engine pulley and atop the
transmission ensure disengagement by forcing the belt
to loop around the engine pulley (Fig. 115).
WPM Drive Systems Manual
Fig 115 3428-0196
THREE SPEED TRANSMISSION

Speed Reduction System:

Speed reduction is accomplished by two sets of gears
– one set on the intermediate shaft and the other set on
the output shaft. The gears on the intermediate shaft
are powdered metal and ride on a hexagonal shaft
supported on each end by oil impregnated bushings.
These gears are driven by the pinion at the bottom of the
input shaft. The driven bevel gear turns the shaft so that
all three gears on the intermediate shaft have the same
rotational velocity (Fig. 116).
E E
A. Intermediate shaft
& gears
B. Bevel gear
A A
B B
C C
D D
Fig 116 3428-0058
C. Shift key
D. Gear sleeve
E. Output shaft & gears
4-3