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Mechanisms Design MECN 4110. Professor: Dr. Omar E. Meza Castillo omeza@bayamon.inter.edu http://facultad.bayamon.inter.edu/omeza Department of Mechanical Engineering Inter American University of Puerto Rico Bayamon Campus. Tentative Lectures Schedule.
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Mechanisms Design MECN 4110 Professor: Dr. Omar E. Meza Castillo omeza@bayamon.inter.edu http://facultad.bayamon.inter.edu/omeza Department of Mechanical Engineering Inter American University of Puerto Rico Bayamon Campus
One thing you learn in science is that there is no perfect answer, no perfect measure. A. O. Beckman Topic: Gears
Mechanical Transmissions Belts Chains Gears
Spur Gears Pinion Gear
Spur Gears - Types External Set: Opposite Movement Internal Set: Movement in the same direction
The angular velocity ratio between the gears of a gearset remains constant throughout the mesh. The angular velocity ratio (mV) is equal to the ratio of the radius of the input gear to that of the output gear The torque ratio (mT) The Fundamental Law of Gearing
The cycloid and the involute: curve characteristics The involute is a curve which can be generated by unwrapping a taut string from a cylinder (called the evolute). Features of this involute curve: The Involute Tooth Form
The Involute Tooth Form • The string is always tangent to the cylinder. • The center of the curvature of the involute is always at the point of tangency of the string with the cylinder. • A tangent to the involute is then always normal to the string, the length os which is the instantaneous radius of curvature of the involute curve.
Contact Ratio If mp is 1, then one tooth is leaving contact just as the next is beginning contact. Spur gears [1-2]. The minimum contact ratio for a smooth operation is 1.2. A minimum contact ratio of 1.4 is preferred and larger is better. Most spur gearsets will have contact ratios between 1.4 to 2.