Page 247 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Power Transmission Gears 229

probably the hypoid since it is the main drive gear in an automotive dif-
ferential.
Worm gears and straight bevel gears have limited application due to
size limits on bevels and sliding velocity limits on worm gears. Spur
gearing is also limited since, for a given situation, it must be much larger
than helical gearing to transmit the required horsepower, and in addition,
it is not well suited for higher speed applications. Spur gears are very
common for high torque low speed drives such as kilns, ball mills, and
sugar mills.

STRAIGHT BEVEL SKEW BEVEL
GEARS GEARS
Figure 6-4. Drawing illustrating straight and skew bevel gear sets.

SPIRAL BEVEL ZEROL BEVEL
GEARS GEARS
F~ure 6-5. Spiral and Zero1 bevel gears and pinions.