Spur gears are one of the most popular types of precision cylindrical gears. These gears feature a simple design of straight, parallel teeth positioned around the circumference of a cylinder body with a central bore that fits over a shaft. In many variants, the gear is machined with a hub which thickens the gear body around the bore without changing the gear face. The central bore can also be broached as to allow the spur gear to fit onto a spline or keyed shaft.
Spur gears are used in mechanical applications to increase or decrease the speed of a device or multiply torque by transmitting motion and power from one shaft to another through a series of mated gears.
The design and construction of a spur gear significantly influence its performance. To do their jobs effectively and efficiently, they need to be fabricated from high-quality materials and to precise dimensions. The dimensional measurements of each feature are integral to how a specific gear functions. As such, when an industry professional requires a new spur gear design or a replacement spur gear, it is imperative that they are familiar with the terms for each gear part and their respective measurements to ensure clarity and accuracy in the production or purchase order.