Topics: Gear, Gears, Pinion Pages: 12 (3938 words) Published: March 2, 2011

Submitted To:
Miss Analyn P. Apsay, MAEd

Submitted By:
Jojie B. Gallo BSME3


Topic Outline1.

(Gear terminologies, definitions and identifying the parts)
(Identifying the types of gears)
(Gear applications or uses)2.

(History of gears)
(Gear calculations or formula)
(Materials for manufacturing gears)3.

(Advantages of gears in the industry)
(Advantages of gears compare to other drive mechanism)4.


Thesis Statement:Gears are important in the mechanical fields and industries

I. Introduction

A. Definition of gear and its principal parts

B. Identifying the types of gears

C. Gear applications

II. History of Gear

A. The beginning of gears in human works

B. Law of gearing and calculations

C. Materials in manufacturing gear

III. Conclusion

A. Advantages of gear technology

B. Comparison with other drive mechanisms

I. Introduction
Gears are the most common means of transmitting power in mechanical engineering. There are tiny gears for devices like wrist watches and there are large gears that some of you might have noticed in the movie like Titanic. Gears from vital elements of mechanisms in many machines such as vehicles, metal tooling machine tools, rolling mills, hoisting and transmitting machinery, marine engines, and the like. Toothed gears are used to change the speed, power, and direction between an input and output shaft. Gears have existed since the invention of rotating machinery. Because of their force-multiplying properties, early engineers used them for hoisting heavy loads such as building materials.

Gears are composed of different parts that play an important role or purposes In order to operate from its work. This are: addendum which is the height of tooth above pitch circle or the distance between the pitch circle and the top of the tooth. The circle that bounds the outer ends of the teeth is called addendum circle or outside circle. Arc of action is the arc of the pitch circle through which a tooth travels from the first point of contact with the mating tooth to the point where the contact ceases. In a pair of gears, the axial plane is the plane that contains the two axes, in a single gear; it may be any plane containing the axis and the given point. Backlash is the amount by which the width of a tooth space exceeds the thickness of the engaging tooth on the pitch circles. The base circle is the circle from which an involute tooth is generated or developed. Base helix angle can be found at the base cylinder if an involute gear, that the tooth makes with the gear axis. In an involute gear, the base pitch is found on the base circle or along the line of action. The normal base pitch is the base pitch in the axial plane. The center distance is found between the parallel axes of the spur gears and parallel helical gears, or between the crossed axes of helical gears and worm gears. It is also the distance between the centers of the pitch circles.

Circular pitch is the length of the arc of the pitch circle between the centers or other corresponding points of adjacent teeth while the normal circular pitch is the circular pitch in the normal plane. The length of the arc between the two sides of a gear tooth is the circular thickness while the normal circular thickness is the circular thickness in the normal plane. The clearance is the radial distance between the top of a tooth and the bottoms of the mating tooth space. The smallest diameter on a gear tooth with which the mating gear makes contact is the central diameter. The contact ratio is the ratio of the arc of action to the circular pitch. It is sometimes thought of as the average number of teeth in contact. The curved formed by the path of a point on a circle as it rolls along a straight line is called cycloid. The dedendum is the depth of tooth space...
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