Kuggparter

Kuggparter is a term used in Swedish gear technology referring to the pairs of gear teeth that mesh as gears rotate. Each kuggpar consists of a tooth on the driving gear and its mate on the driven gear that are in contact along the line of action during meshing. The interaction of kuggpar governs the transmission of torque and the distribution of contact forces between the gears.

The number of active kuggpar at a given moment is described by the contact ratio. A higher contact ratio means more tooth pairs share load, which improves smoothness and reduces noise and peak stresses. The geometry of the tooth profile (often involute), the module, number of teeth, pressure angle, and shaft alignment determine how many kuggpar engage and for how long during each rotation.

In practice, designers aim for a favorable balance: sufficient contact ratio to maintain continuous engagement (often >1), while avoiding interference in external gears or undercut in gears with few teeth. Helical gears and herringbone gears feature multiple kuggpar along a helical contact, distributing load over many teeth; planetary gear systems involve several simultaneous kuggpar across different gear meshes.

The term appears in Swedish engineering literature and is used mainly to discuss meshing behavior in spur, helical, and planetary gears. See also: gear, gear tooth, gear train, involute gear, contact ratio.