Lubricating installation for rocking power transmission box

A lubrication installation for a tilting power box (13–17), intended to rotate at least a driven body (22) driven about an axis of rotation (A—A) that is itself designed to swivel about a tilting axis (B—B), more or less perpendicular to said axis of rotation (A—A) of said driven body (22), said power box including a tilting crankcase (23) mounted to tilt about said tilting axis (B—B) on a non-tilting rigid support (30), the installation comprising:

• at least one lubricating circuit (37a, 37b) under pressure for at least one device to be lubricated that is housed in the tilting crankcase (23), said lubricating circuit comprising a radial transfer stage (47a, 47b) for liquid lubricant under pressure, between two cylindrical journals (56, 57) facing each other, approximately coaxial about the tilting axis (B—B), and of which one is a fixed journal (56) arranged on a fixed part (31) integral with said non-tilting support (30), and the other is a swiveling journal (57) mounted on a swiveling part (58) integral with the tilting crankcase (23),
• said radial transfer stage (47a, 47b) comprising two annular seals (62a, 63a, 62b and 63b) having a prone U-shaped cross-section, with the concavity of each turned to face the other and spaced from one another along the tilting axis (B—B), so that an annular chamber (64a, 64b) of pressurized liquid lubricant is contained between said two annular seals (62a, 63a, 62b and 63b) and the two journals (56, 57), said annular chamber (64a, 64b) being fed with liquid lubricant under pressure by an inlet hole (70a, 70b) emerging in the fixed journal (56) between said two annular seals (62a, 63a, 62b and 63b) and with the downstream end of at least one supply duct (46e, 46b) integrated into said fixed part (31) and whose upstream end is connected to at least one source (34a, 34b) of pressurized lubricant, and also, feeding the tilting crankcase (23) in liquid lubricant under pressure through an outlet hole (71a, 71b) emerging in the swiveling journal (57) between said two annular seals (62a, 63a, 62b and 63b) and at the upstream end at least one distribution pipe (48a, 48b) extending into the swiveling part (58) and emerging in the tilting crankcase (23).