pitch circle

noun

, Machinery.

1. an imaginary circle within the profiles of the teeth of a gear, such that it rotates against a similar circle rotating at the same rate on a meshing gear.

pitch circle

noun

1. an imaginary circle passing through the teeth of a gearwheel, concentric with the gearwheel, and having a radius that would enable it to be in contact with a similar circle around a mating gearwheel

Word History and Origins

Origin of pitch circle¹

First recorded in 1810–20

Example Sentences

Another plan is to employ two or three cutters, one having the correct curve for the inner diameter, and of the correct thickness for that diameter, another having the correct curve for the pitch circle, and another having the correct curve at the largest diameter of the teeth.

From Project Gutenberg

From 1 to 6 are points of equal division on the pitch circle, and d to i are arc locations for the centre of the generating circle.

From Project Gutenberg

Then from 1 to 6 are points of equal division on the pitch circle, and from d to i are the corresponding locations for the centres of the generating circle.

From Project Gutenberg

Draw the radial line l, meeting the pitch circle at a.

From Project Gutenberg

It is obvious that by reason of this taper each wheel is larger in diameter on one side than on the other, hence to preserve the true curves to the teeth the pitch circle is made correspondingly smaller.

From Project Gutenberg