Helical Rack Theory
The Helical Rack is defined as a rigid body. A finite stiffness for the rack mesh (or rack tooth) can be specified in the Rack and Pinion node while connecting to a pinion. Similar to the rigid domain, the helical rack is a material model, which is mutually exclusive to all other material models. The only material property needed is the mass density.
Figure 3-9: Sketch of a helical rack, showing the tooth cross-section and various parameters such as center of rotation, rack axis, pitch, radial offset, tangential offset, 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 Rack Theory section, which is also applicable for the helical rack.
Rack properties
The additional parameter helix angle (β) is required to define a helical rack.
The normal pitch of the rack is defined as: