Inter-shaft bearing for multibody turbojet engines with damping by a film of oil

A bearing for multibody turbomachines of the type supporting in rotation a first shaft (2) defining a line journal of a high pressure body in relation to a second shaft (3) defining the line journal of a low pressure body and comprising a roller bearing (4) with rollers (5) inserted between an inside bushing (6) mounted on the first shaft (2) and an outer bushing (7) contained in a box (10), itself mounted on the second shaft (3), and a lock nut (12) maintaining the inner bushing (6) on said first shaft, said nut (12) having on its internal face an annular recess (16), supplied with oil by the centrifugal effect from an inlet (17) located on the second shaft (3), wherein from the recess (16) of the nut (12), oil is distributed on the one hand over the inner track (8) of the roller bearing (4) toward the rollers (5) to ensure the lubrication and cooling of the bearing, and on the other, to the outer bushing (7), wherein a radial clearance (18) provided between the outer bushing (7) and the box (10) of the roller bearing constitutes a space (19), where a film of oil is introduced under pressure, to ensure the damping of vibrations generated on the second shaft (3) and wherein the entirety of the oil distributed is returned for recycling by way of the outside of the box (10) of the roller bearing characterized in that:

• the recess (16) of the nut (12) constitutes a first chamber comprising means to assure the accurate division of the flows of oil distributed on the one hand over the inner bushing and on the other, over the outer bushing,
• the box (10) of the outer bushing (7) comprises an annular collector (21) constituting a second chamber entrained in rotation by the second shaft (3) and receiving the oil centrifuged from the recess (16) of the nut (12), constituting the first chamber, entrained in rotation at a different velocity by the first shaft (2), said collector (21) supplying oil under pressure to the film formed in the space (19) provided between the outer bushing (7) and the box (10) and having a predetermined radial height such as to obtain a satisfactory pressure and oil flow of the film,
• return of the oil being effected, at each end of the box (10) of the roller bearing, by means of an upstream circuit (42) and a downstream circuit (44), comprising internal means to ensure the balancing of the flows and pressures of the oil in both circuits, in a manner so as to maintain the correct centering of the bearing,
• the shafts (2) and (3) including centering means to guide the shafts (2) and (3), during installation, within each other, without the radial clearance (18) provided between the outer bushing (7) and the box (10) leading to harmful contact between the shafts.