Preparation of textile preforms for brake discs in composite material

A method of manufacturing a composite material braking assembly comprising a central rotor brake disk having a core portion and two friction portions adjacent to the core portion on either side thereof and each having a friction face, and two stator disks coaxially arranged with said rotor disk on either side thereof, each stator disk having a core portion and one friction portion adjacent to the core portion and having a friction face facing a respective friction face of the rotor disk, said disks being in a composite material having a fiber reinforcement densified by a matrix, said method comprising the steps of:

• preparing four substantially identical fiber preforms, each by forming a first fiber preform portion that is to constitute the fiber reinforcement of at least a part of a core portion of a disk by superposing and bonding together by needling fiber layers comprising structural layers formed at least in part out of continuous filaments, and by forming a second fiber preform portion that is to constitute a fiber reinforcement of a friction portion of a disk, said second preform portion being constituted by at least one felt layer bonded to the first fiber preform portion by needling,
• densifying the four fiber preforms with a matrix,
• putting two of the densified fiber preforms together via their first preform portions so as to obtain a densified preform for a rotor disk having two friction portions, and machining said two densified preforms to the final dimensions of a rotor disk, and
• machining each of the two other densified preforms to the final dimensions of a stator disk,
• whereby a braking assembly is obtained with a rotor disk and two stator disks each having a fiber reinforcement including structural layers in its core portion and having a fiber reinforcement constituted by felt adjacent the friction face of its friction portion(s).