ABSTRACT

As it is adopted in this book, the determination of a set of design parameters of a work gear is the starting point when designing a gear cutting tool.

21.1.1 Geometry of an Internal Gear

An example of an internal gear is illustrated in Figure 1.3. The location of the gear body with respect to the tooth surfaces is the major difference of the geometry of an internal gear from the geometry of an external gear (see Figure 1.4). Therefore, Equation (1.3)

b.g g g( , )

cos cos sin

sin s U V

r V U V

r V U =

+

λ in sin

tan sin

λ λ λ

V

r U−



 1

≤ ≤

≤ ≤

V V V

U U

[ ],0 (2.1.1)

is valid for the internal gear as well. The body of an external gear is located within the interior, which is bounded by the sur-

face G. In contrast, the body of an internal gear is located outside the surface G.