Straight
bevel gears is a gear, shaped like
a right circular cone where the axes of
the two shafts intersect. Straight
bevel gears are mounted on shafts
that are 90 degrees apart, and designed
to work at other angles as well. The gears
that pitch angles less than 90 degree is
called external as the gears teeth point
outward and the one that makes angle more
than 90 degree called internal as it point
inward bevel
gears. The teeth on
straight bevel gears can be straight,
spiral and hypoid.
The straight bevel gears
are the simplest form of bevel gears and
have no helix angle. The teeth are parallel
and straight to the generators. It reassembles
the spur gears in conical shape rather than
cylindrical shape. Straight bevel
gears are used in the floodgate
pictures. In straight each tooth engages
with the corresponding tooth and simply
curving the gear teeth can solve the problem.
Spiral bevel gears have
spiral angles which improve their performance
and have teeth formed along spiral lines.
They engage more gradually than straight
bevel gears and analogously to
the way helical gear teeth. The contact
of teeth starts at one end of the gear and
then spreads across the whole tooth in spiral.
In both the bevel types of gears the shaft
must be perpendicular to each other and
be in the same plane.
The hypoid bevel gears
engage the axes in different plane. It is
used in cars. The hypoid gears are used
in the ring gears of the differential and
the input pinion.
The applications of straight bevel
gears find in locomotives, marine
applications, automobiles, printing presses,
cooling towers, power plants, steel plants
and defence . Straight bevel gears
change the operating angle.
|
