A cage for a ball bearing comprising a body of generally annular shape and clamps, the body comprising a heel of substantially annular shape and a substantially axial portion being connected to the heel and wherein recesses are arranged for the balls, the substantially axial portion supporting said clamps on the side axially opposite to the heel, the cage comprising an axial partition placed between the recesses and extending axially from the end of the heel opposite to the clamps toward the clamps while radially delimiting external free spaces and internal free spaces situated radially on either side of said partition.