Build Your Own Combat Robot

The power transmitting capability of a V-belt is dependent on the belt tension
and the angle of wrap around the sheave. The greater the belt tension, the greater
the torque transmitting capability. As with synchronous belts, V-belts are available
only in fixed lengths. To determine which size of V-belt to use, you should
consult the belt specification datasheets from the belt manufacturer.
For combat robots, V-belts could be used for drive belts in the power transmission
and for speed reduction applications. But the most common use for V-belts is
for driving weapons. As with flat belts, using V-belts in this way will allow the belt
to slip if the weapon is stalled. With V-belts, more torque can be transmitted from
the motor to the weapons, thus making them more effective than regular flat belts.
The belt slippage when the weapon has stalled may be desirable in this situation
because the drive motors are protected from complete stall and possible burnout.
G earboxes
FIGURE 6-10
A worm gearbox
attached to an
electric motor.
Note the screwtype
gear in
the center of
the gearbox.
Chapter 6: Power Transmission: Getting Power to Your Wheels 121
The compact form of a power transmission is to use a gearbox between your motors
and wheels. Earlier, we talked about using gearmotors for robots. A
gearmotor consists of a gearbox mounted to an electric motor. Inside the gearbox
are gears, shafts, bearings, oil/grease, and a rigid case. A gearbox consists of precisely
designed components. Within a gearbox there are various configurations of
gears to obtain the speed reduction. The common methods consists of spurs gears,
planetary gears, helical gears, worm gears (shown in Figure 6-10), or some combination
of these gears.