Transcript Motion Transmission Systems

Motion Transmission Systems
1.
2.
the mechanical fxn of relaying
motion from 1 part to another
without altering the nature of
the motion
a set of components that
perform the fxn of transmitting
motion
Characteristics of Motion
Transmission Systems
All the systems transmit rotational motion.
1) The direction of rotation is sometimes
identical throughout and sometimes different
e.g. clockwise versus counterclockwise.
2) Reversing the sys may not always be possible.
5 Systems
1) Gear Trains
2) Chain and Sprocket
3) Worm and Worm Gear
4) Friction Gear
5) Belt and Pulley
Gear Trains
1) Direction alternates from 1 gear to next.
2) Reversible.
Elements to consider when
building a Gear Train
At least 2 gears.
Used to transmit motion btw 2 or more
closely positioned parts.
All teeth must be identical = same shape and
spacing.
Straight Gears when axes are parallel.
Bevelled Gears when axes are perpendicular.
The higher the number of teeth/the larger the
diameter = the slower the speed.
Gear Train Animation
• http://www.youtube.com/watch?v=CgXCFw39
Gkw&feature=player_detailpage
Chain and Sprocket Systems
Identical rotation for sprockets touching same
side of chain.
The 2 or more gears DO NOT mesh; they are
connected by a chain.
Used to transmit motion btw distant parts.
The teeth on the sprockets must be identical.
The chain links mesh with the sprocket teeth.
Frequent lubrication necessary.
The smaller a sprocket the faster it turns.
Chain and Sprocket
http://www.youtube.com/watch?v=_GVq9O9m
FCs&feature=player_detailpage
Worm and Worm Gear
Direction of Rotation varies with the threads
on the worm screw shaft.
Not reversible!
Single worm (endless screw) whose rotational
motion is transmitted to one or more worm
gears.
The groove of the worm must fit the gear
teeth.
The driver is the worm.
Worm and Worm Gear Animation
http://www.youtube.com/watch?v=mNI0TwHK
Ni4&feature=player_detailpage
Friction Gear Systems
Direction alternates from 1 gear to next.
Reversible.
No teeth.
Friction btw gears.
Closely placed parts.
More economical and less complicated.
Less efficient because gears can slip.
Straight, Bevelled and Spherical gears.
Belt and Pulley Systems
Identical direction for pulleys touching on the
same side of the belt.
Toothless gears are referred to as pulleys
connected by a belt.
Btw 2 or more distant parts.
Pulleys must contain a smooth groove where
the belt can fit.
The belt must adhere to the pulley to avoid
slipping.
The smaller the pulley the faster it turns.
Belt and Pulley Systems
http://www.youtube.com/watch?v=OqrsEUVNA
Js&feature=player_detailpage