Tenningkurve

Tenningkurve, literally meaning “toothing curve,” is the curve that defines the profile of a gear tooth. In contemporary gear design the most common form is the involute of a circle, a shape that supports a constant velocity ratio during meshing and simplifies transmission geometry.

Generation and geometry: An involute is generated by unwinding a taut string from a base circle; the end point traces the involute curve, which becomes the flank of each tooth when mirrored for the opposite side. The pitch circle, base circle, addendum and dedendum together determine tooth spacing, height and overall geometry. The base circle radius is a key reference in defining the involute profile.

Line of action and contact: Meshing gears interact along the line of action, a straight line tangent to both base circles. The path of contact along this line begins where the driving gear’s addendum intersects the line of action and ends where the driven gear’s addendum ends. The involute profile ensures a favorable contact ratio and smooth force transmission over much of the rotation.

Variants and manufacturing: While involute profiles dominate modern gear sets, other tooth forms (such as cycloidal profiles in specific applications) exist. The tenningkurve guides manufacturing operations, with hobbers, gear shapers or milling cutters designed to generate the intended curve accurately.

Importance: The tenningkurve underpins gear performance, influencing load distribution, efficiency, noise, and manufacturability. It is a foundational concept in mechanical power transmission and gear design. See also gear, involute of a circle, line of action, base circle, addendum and dedendum.