System for gearing

1. A system for gearing, the system comprising a toothed wheel mounted on a shaft, the wheel being pierced by channels fed with lubricant, each channel opening out to the toothed periphery of the wheel,

wherein said wheel is mounted on an end portion of the shaft, so as to be capable of being rotated by said shaft,

wherein said end portion is hollow so as to present an inside chamber, said chamber opening out to the outside of the shaft, via an orifice situated at an end of the shaft, and

wherein said channels communicate with said chamber,

the system including an injector for injecting lubricant into the chamber, the injector being situated outside the chamber, not being in contact with the shaft, and facing said orifice in such a manner as to inject the lubricant through said orifice, the lubricant penetrating into and flowing along the channels to the toothed periphery of the wheel under the effect of centrifugal force associated with rotation of the shaft,

wherein the end portion of the shaft is provided with a rim which extends radially relative to an axis of rotation of the shaft and surrounds said orifice, the chamber being defined by the rim which serves to retain lubricant fluid in the chamber, and

wherein the shaft is adapted to rotate around an axis of rotation, wherein each channel communicates with the chamber via an inlet orifice situated in a side wall of the chamber, and wherein said injector has an injection axis passing through the orifice and being inclined relative to the axis of rotation of the shaft towards said side wall in such a manner that the lubricant comes directly into contact with the side wall.

2. A system for gearing according to claim 1 , wherein the shaft is adapted to rotate around an axis of rotation, said orifice being centered on the axis of rotation.

3. A system for gearing according to claim 1 , wherein each channel opens out between two successive teeth of the wheel.

4. A system for gearing according to claim 1 , wherein the wheel presents at least one circular groove in its toothed periphery, with the channels opening out into the groove, the channels and the groove having axial widths such that the axial width of said groove is greater than the axial width of the channels.

5. A system for gearing according to claim 1 , wherein nozzles are mounted in the channels at the toothed periphery of the wheel, these nozzles presenting a fluid flow section that is smaller than that of the channels.

6. A system for gearing according to claim 1 , wherein the channels are rectilinear.

7. A system for gearing according to claim 1 , wherein the channels extend radially relative to the axis of rotation of the shaft.

8. Gearing including the system of claim 1 and at least one other toothed element meshing with the wheel of the system.

9. A turbomachine including the gearing of claim 8 .

10. A system for gearing according to claim 1 , wherein the shaft has an end face, said orifice being situation in the end face of the shaft.

11. A system for gearing according to claim 1 further comprising a casing which surrounds the wheel and the end of the shaft, the shaft passing through a first wall of the casing, wherein the injector is mounted through a second wall of the casing.