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BEH 41103
MECHATRONIC MECHANISM
DR DIRMAN HANAFI BURHANNUDDIN
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GEAR SYSTEMS
A gear is a component within a transmission device that
transmits rotational force to another gear or device
http://en.wikipedia.org/wiki/Rotationhttp://en.wikipedia.org/wiki/Rotation -
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GEAR CLASSIFICATION
A. PARALLEL
Gears for connecting parallel shafts
1. Spur Gear
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EXTERNAL AND INTERNAL SPUR GEAR
APPLICATIONS OF SPUR GEAR
Electric screwdriver, dancing monster, oscillating sprinkler, windup alarm
clock, washing machine and clothes dryer
http://www.howstuffworks.com/inside-sd.htmhttp://www.howstuffworks.com/dancing-monster.htmhttp://www.howstuffworks.com/sprinkler.htmhttp://www.howstuffworks.com/inside-clock.htmhttp://www.howstuffworks.com/inside-clock.htmhttp://www.howstuffworks.com/washer.htmhttp://www.howstuffworks.com/dryer.htmhttp://www.howstuffworks.com/dryer.htmhttp://www.howstuffworks.com/washer.htmhttp://www.howstuffworks.com/inside-clock.htmhttp://www.howstuffworks.com/inside-clock.htmhttp://www.howstuffworks.com/sprinkler.htmhttp://www.howstuffworks.com/dancing-monster.htmhttp://www.howstuffworks.com/inside-sd.htm -
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2. Parallel Helical Gear
CROSSED HELICAL GEAR
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Herringbone gears
Herringbone gears (or double-helical gears)
Applications of Herringbone Gears
The most common application is in power transmission. They
utilize curved teeth for efficient, high capacity powertransmission. This offers reduced pulsation due to which they are
highly used for extrusion and polymerization. Herringbone gears
are mostly used on heavy machinery.
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3. Rack and pinion
RACK AND PINION
Rack and pinion gears are used to convert rotation (From thepinion) into linear motion (of the rack). A perfect example of
this is the steering system on many cars.
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B. GEARS FOR CONNECTING INTERSECTING SHAFTS
1. Straight Bevel Gear
BEVEL GEAR SPIRAL BEVEL GEAR
The bevel gear has many diverse applications such as
locomotives, marine applications, automobiles, printing presses,
cooling towers, power plants, steel plants, railway track inspection
machines, etc.
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C. NON-INTERSECTING AND NON-PARALLEL
1. WORM AND WORM GEAR
WORM AND WORM GEAR
Worm gears are used when large gear reductions are needed. It
is common for worm gears to have reductions of 20:1, and even up to300:1 or greater.
Application: Worm gears are used widely in material handling and
transportation machinery, machine tools, automobiles etc.
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NOMENCLATURE OF SPUR GEARS
NOMENCLATURE OF SPUR GEAR
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1. Pitch surface: The surface of the imaginary rolling cylinder(cone, etc.) that the toothed gear may be considered to replace.
2. Pitch circle: A right section of the pitch surface.3. Addendum circle: A circle bounding the ends of the teeth, in aright section of the gear.
4. Root (or dedendum) circle: The circle bounding the spacesbetween the teeth, in a right section of the gear.
5. Addendum: The radial distance between the pitch circle and
the addendum circle.6. Dedendum: The radial distance between the pitch circle and
the root circle.
7. Clearance: The difference between the dedendum of one gearand the addendum of the mating gear.
8. Face of a tooth: That part of the tooth surface lying outside thepitch surface.
9. Flank of a tooth: The part of the tooth surface lying inside thepitch surface.
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10. Tooth space: pitch diameter The distance between adjacentteeth measured on the pitch circle.
11. Backlash: The difference between the circle thickness of onegear and the tooth space of the mating gear.12. Circular pitch (Pc) : The width of a tooth and a space,
measured on the pitch circle.
13. Diametral pitch (Pd): The number of teeth of a gear unit pitchdiameter. A toothed gear must have an integral number of teeth.
The circular pitch, therefore, equals the pitch circumference
divided by the number of teeth.
14. Fillet: The small radius that connects the profile of a tooth to theroot circle.
15. Pinion: The smaller of any pair of mating gears. The larger of
the pair is called simply the gear.16. Velocity ratio: The ratio of the number of revolutions of the
driving (or input) gear to the number of revolutions of the driven
(or output) gear, in a unit of time.
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17. Pitch point: The point of tangency of the pitch circles of a pair
of mating gears.18. Common tangent: The line tangent to the pitch circle at the
pitch point.
19. Line of action: A line normal to a pair of mating tooth profilesat their point of contact.
20. Path of contact: The path traced by the contact point of apair of tooth profiles.
21. Pressure angle ( ): The angle between the common normalat the point of tooth contact and the common tangent to the
pitch circles. It is also the angle between the line of action and
the common tangent.22. Base circle: An imaginary circle used in involute gearing to
generate the involutes that form the tooth profiles.
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VELOCITY RATIO OF GEAR DRIVE