Helical Gear Theory
The Helical Gear model is defined as a rigid body. A finite stiffness for the gear mesh (or gear tooth) can be specified in the Gear Pair node while connecting to other gears. Similar to the rigid domain, the helical gear is a material model, which is mutually exclusive to all other material models. The only material property needed is the mass density.
Figure 3-4: Sketch of an external helical gear, showing the tooth cross section and various parameters such as center of rotation, gear axis, pitch radius, pressure angle, and helix angle.
Figure 3-5: Sketch of an internal helical gear, showing the tooth cross section and various parameters such as center of rotation, gear axis, pitch radius, pressure angle, and helix angle.
For details about the theory of a rigid body, see the Rigid Domain Material Model section in the Structural Mechanics Module User’s Guide.
The following section is an addition to the Spur Gear Theory section, which is also applicable for the helical gear.
Gear properties
The additional parameter helix angle (β) is required to define a helical gear. The positive helix angle is interpreted as right handed and the negative helix angle is interpreted as left handed.
The normal module of the gear is defined as: