Tread with reduced road noise

A tire for a heavy goods vehicle axle, comprising a tread of which a tread surface is designed to come into contact with a roadway, this tread comprising a plurality of circumferential grooves delimiting intermediate ribs and two edge ribs, the intermediate ribs having no transverse grooves opening into two circumferential grooves, each rib having a minimum width Ln and comprising two lateral walls and a contact face designed to come into contact with a roadway, each circumferential groove comprising a plurality of protuberances formed as a protrusion on at least one lateral wall delimiting this groove in order to partly obstruct the cross section of the circumferential groove in question, this tread comprising:

• facing each protuberance, on the adjacent rib delimiting the groove in question, a half-closed notch having an axial length La at most equal to 60% of the minimum width Ln of this rib, this half-closed notch with a width Le at most equal to the width Lr of the groove being oriented so as to make an average angle B at least equal to 10 degrees with the main direction of the protuberance with which this notch interacts,
• wherein protuberance closes the section of the groove in which it is formed over at least 30% and at most 75% of the surface of the said section,
• and wherein a functional clearance (J1, J2) is arranged between the protuberance and the walls delimiting the half-closed notch with which this protuberance is designed to interact, in order to allow the passage of fluid, notably when running on a water-covered roadway, and
• each protuberance extends to an opening of a corresponding half-closed notch.