Fibrous preform of a friction part

1 . A fibrous preform for forming a fibrous reinforcement of a friction part made of composite material, comprising a woven helical fibrous texture defining a superposition of fibrous layers, said texture being needled and defining:

a first portion and a second portion each intended to define a distinct rubbing face of the friction part and each comprising at least one fibrous layer comprising ceramic particles, the ceramic particles are discontinuously present on a surface of the fibrous layers of the first and second portions with an alternation along a circumferential direction of the fibrous layers between areas comprising the ceramic particles and areas devoid of ceramic particles at the rubbing faces, fibers of the fibrous layers of the first and second portions being present into the areas devoid of ceramic particles, and

an intermediate portion between the first portion and the second portion and comprising at least one fibrous layer, said intermediate portion being devoid of ceramic particles,

wherein the first and second portions each comprise a first fibrous layer having first areas in which the ceramic particles are present, and a second fibrous layer, superimposed on the first fibrous layer, having second areas in which the ceramic particles are present, the second areas not covering the first areas, and wherein the second fibrous layer comprises additional areas devoid of ceramic particles with an alternation along the circumferential direction between the second areas and said additional areas, and

wherein, in said alternation, the first areas of the first fibrous layer in which the ceramic particles are present are superimposed with the additional areas of the second fibrous layer that are devoid of ceramic particles.

2 . The fibrous preform according to claim 1 , wherein the ceramic particles are present in areas extending along a radial direction of the fibrous layers of the first and second portions.

3 . The friction part made of composite material comprising a fibrous preform according to claim 1 , and a matrix present in the porosity of the fibrous preform.

4 . The friction part according to claim 3 , wherein the friction part is a brake disc.

5 . The fibrous preform according to claim 1 , wherein the first and second portions each comprise a third fibrous layer, superimposed on the first and second fibrous layers, having third areas in which the ceramic particles are present, the third areas not covering the first and second areas, and wherein the third fibrous layer comprises supplemental areas devoid of ceramic particles with an alternation along the circumferential direction between the third areas and said supplemental areas.

6 . The fibrous preform according to claim 1 , wherein the areas devoid of ceramic particles comprise solely fibers from the fibrous layers of the first and second portions.

7 . A manufacturing method of a fibrous preform according to claim 1 , comprising:

needling a first part of a woven helical fibrous web to form the first portion of the fibrous texture, wherein ceramic particles are distributed on said first part during said needling,

needling an intermediate part of the woven helical fibrous web to form the intermediate portion of the fibrous texture, said intermediate part being superimposed on the first part and the distribution of the ceramic particles being interrupted during said needling, and

needling a second part of the woven helical fibrous web to form the second portion of the fibrous texture, said second part being superimposed on the intermediate part and ceramic particles being distributed on said second part during said needling,

the ceramic particles being discontinuously distributed on a surface of the fibrous layers of the first and second portions of the woven helical fibrous web with an alternation along the circumferential direction of the fibrous layers between areas comprising the ceramic particles and areas devoid of ceramic particles at the rubbing faces,

wherein when needling each of the first and second portions of the woven helical fibrous web, the following is carried out:

needling the first fibrous layer during which ceramic particles are discontinuously deposited in the first areas on the surface of the first fibrous layer, and

needling the second fibrous layer, superimposed on the first fibrous layer, during which the ceramic particles are discontinuously deposited in the second areas on the surface of the second fibrous layer, the second areas not covering the first areas, wherein the second fibrous layer comprises the additional areas devoid of ceramic particles with the alternation along the circumferential direction between the second areas and said additional areas, and wherein, in said alternation, the first areas of the first fibrous layer in which the ceramic particles are present are superimposed with the additional areas of the second fibrous layer that are devoid of ceramic particles.

8 . The method according to claim 7 , wherein the ceramic particles are distributed by a distribution system moving along a radial direction of the fibrous layers of the first and second portions.