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Applications Note – Gears
Mike Priebe
November 7, 2008
Executive Summary
The general purpose of a gear is to transfer motion from one object to
another in a mechanism. The important design considerations for the design of
gears in a mechanism are the gear ratio, which determines the proper number of
teeth to use, and also the type of gear to use, which depends on the application.
An example of gears being designed for a mechanism is in the design of the PI
Engineering Ship Simulator. In this project, gears were used to transfer the
rotational motion of the steering wheel to a hydraulic motor. The methods
outlined in this applications note were utilized in the design process.
Keywords
1. Gear - a component within a transmission device that transmits rotational
force to another gear or device.
2. Teeth – linkages on a gear that mesh with other gear teeth, allowing force
to be fully transferred without slippage.
3. Gear Ratio - the relationship between the number of teeth on two gears
that are meshed.
Introduction
Gears have many uses in mechanics; a gear’s most general purpose is to
transfer rotational motion from one shaft to another. Linear motion can also be
obtained through a rack and pinion system. There are many different types of
gears, including spur gears, bevel gears, crown gears, and worm gears. The
type and size of gear chosen for a given application depends on the desired
output specifications. For example, if more torque is required on the output shaft,
then a larger gear would need to be placed on the output shaft relative to the
input shaft, thus producing mechanical advantage. The following is an aide in
the use of gears in the design of a mechanism.
