10.4 GEARCALC/ page 4

10.4.1 Center distance

The standard center distance C{a} is dependent upon ratio, tooth pitch, and pressure angle. Standard Center Distance:

A pair of gears may operate on modified or standard center distance. The standard center distance is given by:

For gears that operate on standard centers:

C = C_STD

Modified Center Distance:

For gears that operate on modified centers, the center distance modification is:

ΔC=C-C_STD

10.4.2 Pitch diameter pinion

The value for the pitch diameter of the pinion is normally calculated and entered here. The value can be directly entered by checking the box by the side of the field.

10.4.3 Net face width

The net contacting face width F{b} excludes any face width that is non-contacting because of chamfers or radii at the ends of the teeth. For double-helical gears the net face width equals the total face width minus the gap between the helices.

10.4.4 Normal diametral pitch

The normal diametral pitch is shown if US customary units are selected as a default (see 1.3.3). For metric units also the normal module can be shown instead.

The normal diametral pitch defines the size of a tooth. It is π divided by the normal pitch P_nd = π∕p. So the tooth thickness increases with a decreasing normal diametral pitch. The value can be directly entered by checking the box by the side of the field. So you have the possibility to select a standard value.

10.4.5 Normal module

The normal module m_n is only shown if metric units are selected (see 1.3.3). For US customary units you see the normal diametral pitch instead.

The normal diametral pitch defines the size of a tooth. It is the normal pitch divided by π m_n = p∕π. So the tooth thickness increases with an increasing module. The value can be directly entered by checking the box by the side of the field. So you have the possibility to select a standard value (with are normally given in millimeters).