GEAR DRIVES Flashcards
??? play a crucial role in the functioning of
agricultural machinery, providing the necessary power
transmission and torque conversion mechanisms for various
operations.
Gear drives
??? are machine elements that transmit motion by means of
successively engaging teeth. The gear teeth act like small
levers.
Gears
Types of Gears
- Spur Gears
- Helical Gears
- Bevel Gears
- Rack and Pinion Gears
- Miter Gears
- Worm and Worm Gear
???, which have
teeth shaped in cylindrical
blanks parallel to the shaft
axis, are used to join parallel
shafts. They can be used to
transfer power and motion in
the same direction or in the
opposite way between two
shafts. Moreover, they are
useful for communicating
linear motion
Spur gear
??? can be used
in transmitting motion and
power between two shafts in
the same or in opposite
directions. They can also be
used in transmitting linear
motion. ??? are used
for higher speed applications
due to more quiet operation.
Helical Gears
Gears which are used
to transmit motion and
power to shafts having
intersecting axes.
(For this topic, only straight
??? with a shaft
angle of 90° will be
discussed)
Bevel Gears
Each of the projecting
parts of a gear which are intended
to ensure, by contact with the
teeth of another gear, that one of
the other gears turns the other
Gear Tooth
– It is the diameter
of the pitch circle.
Pitch Diameter
the line of
intersection of the pitch cylinder
by a plane perpendicular to the
axis of the gear.
Pitch Circle
It is the ratio of the pitch diameter to the number of
teeth. The unit of the module is millimeters. Below is a diagram
showing the relative size of teeth machined in a rack with
module ranging from module values of 0.5 mm to 6 mm
Module
the radial distance
between the addendum circle and
the pitch circle
Addendum
the circle that
bounds the outer ends of the teeth
Addendum Circle
the radial distance
between the dedendum circle and
the pitch circle
Dedendum
the line of intersection of the dedendum
cylinder by a plane perpendicular to the axis of the gear.
Dedendum Circle –
the amount by which
the dedendum in a given gear
exceeds the addendum of its
meshing gear
Clearance
the
radial distance between the
addendum circle and the
dedendum circle
Tooth Depth (Whole Depth)
the width over the toothed part of a gear, measured
along a straight line generator of the reference cylinder
Face width
the tooth space minus
the tooth thickness
Backlash
the portion of the
surface of a tooth lying between
the tip surface and the root surface
Tooth Flank
the space between
teeth measured along the pitch
circle
Tooth Space
angle at the point
where the profile cuts the pitch
circle
Pressure angle
the line of
intersection of a tooth flank with
any defined surface cutting the
reference
Tooth Profile
the line of
intersection of a flank with the
reference surface
Tooth trace
cylindrical gear of which every
usable tooth profile is an arc of an
involute to a circle.
Involute cylindrical gear
