- [Instructor] There are many different types
of mechanical gears in use today.
This lesson will provide a quick overview
of some of the more common types
of gears and their applications.
Straight spur gears have teeth that are parallel
to the axis of rotation.
This is the most common type of gear
due to its low cost of manufacturer.
These gears can be used to transfer rotation
from one parallel axis to another.
Helical spur gears have teeth
that are cut at an angle across the face of the gear.
These gears can mesh in both parallel
and crossed orientations where the axis
of rotation is perpendicular to one another.
Helical spur gears tend to run smoother
and quieter than straight spur gears,
but they can create a thrust load
on the axis of rotation
and sometimes requires special
thrust bearings to counteract.
A double helical gear, like the one shown here,
is used to counteract the issue of axial thrust
seen with regular helical gears.
The left and the right halves of the gear
develop a thrust force that cancels each other out.
This enables them to be used
for higher load applications than helical spur gears.
It can be found in gas turbines
and marine ship compressors.
Beveled gears are cone-shaped gears
use to transmit rotational motion
between two axis that are not parallel to one another.
They're commonly found in hand drills
and differential drives.
A miter gear is simply a beveled gear
where the angle between the two axis
of rotation is set to 90 degrees.
A spiral beveled gear has helical teeth
like the helical spur gear.
They tend to produce less noise and vibration
than their straight tooth counterpart.
They are commonly found in rotorcraft differentials.
Worm gears are used to obtain large speed reductions
between shafts that are 90 degrees from one another.
These gears provide excellent mechanical advantage
and are self-locking
if the input load is removed from the system.
They are often found in lifting mechanisms,
such as elevators and cranes.