Involute gears: how to measure them

Today we talk about the measurement of gears, a very important topic to allow us to avoid having non-conformities.

Let us specifically analyze the case of the gear with an involute profile, whose peculiarity is that the motion transmission takes place between two conjugated profiles which exchange normal forces, except for small friction components. In a much less technical way, it means that the side of the tooth is rounded, because a curve is described by a point of a straight line which rolls without slipping on a circumference called the base circumference. So, if we had to translate this process in a simplistic way, we could represent it with two wheels in whose meeting point an imaginary inclined straight line passes which forms an angle. The latter rests on the straight line that intersects the two wheels at their meeting point and also determines the formal characteristics of the tooth.

Why is the involute gear used?

Certainly, the reasons are many, first of all the strength of the teeth remains constant in the direction. Also, if the distance between the centers of the two wheels changes, they continue to engage and maintain the same gear ratio. Another really important advantage is that the involute profile gears can be cut with a straight profile tool. This is because the teeth can be made by envelope, i.e. with a mutual movement between the tool and the gear, very similar to that of meshing.

How to check the involute

The technology supports the control of the involute profile, in fact we use the involute gauge. However, it is necessary to support his work with a graph containing multiple measurements of the tooth. The machine measures the entire involute profile of the tooth and collects the data which is then processed and the control card created.

Did you know all the advantages of the involute profile?