Definition of pitch circle in English:

pitch circle

noun

Mechanics
  • An imaginary circle concentric to a toothed wheel, along which the pitch of the teeth is measured.

    • ‘The hypoid gears used in conventional axles do not have a true pitch circle since both sliding and rolling occurs at the teeth and the gears could not be replaced with frictional disks.’
    • ‘The velocity ratio is equal to the inverse ratio of the diameters of pitch circles.’