A turbomachine combustion chamber in which a chamber end wall presents an opening for receiving a pre-vaporization bowl, and including a device for injecting air and fuel mounted on the axis thereof, the bowl being floatingly mounted relative to the chamber end wall to move in a predetermined radial direction and flaring downstream so as to form a collar, a deflector forming a thermal shield being made integrally with the bowl beside the chamber end wall so that the floating movement of the bowl-and-deflector assembly takes place in a sliding plane situated between the deflector and the chamber end wall.