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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