Characteristics of trochoids and their application to determining gear teeth fillet shapes

Some interesting characteristics of trochoids are discussed in this paper and a new concept of virtual involute is introduced. These characteristics prove very useful in determining the exact tooth fillet shape generated by racks consisting of circular arcs and straight line segments. The fillet curves generated by racks with a protuberance or with a chamfered tip are discussed in detail. A numerical example is given to illustrate their application.