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EP-4540534-B1 - BEARING ASSEMBLY LUBRICATED WITH GREASE, IN PARTICULAR FOR WIND TURBINES AND CABLE TRANSPORTATION SYSTEMS, COMPRISING A GREASE COLLECTION AND DISCHARGE SYSTEM

EP4540534B1EP 4540534 B1EP4540534 B1EP 4540534B1EP-4540534-B1

Inventors

  • BONOTTO, Nicola
  • BABUIN, Alessandro

Dates

Publication Date
20260506
Application Date
20230615

Claims (13)

  1. A bearing assembly grease-lubricated, in particular for wind turbines (2) and/or cable transportation systems, wherein the bearing assembly (1) is annular shaped around an axis (A) and comprises: - an outer ring (3); - an inner ring (4), wherein between the inner ring (4) and outer ring (3) an axial gap (5) is provided filled with lubrication grease and extending from a first side (7) to a second side (8) of the bearing assembly (1); - at least one rolling body (6) housed in the gap (5) to allow relative rotation of the rings (3, 4) around the axis (A); characterized in that the bearing assembly (1) also comprises: - a first hermetic seal (9) and a lip seal (10) respectively at the first side (7) and at the second side (8) of the gap (5) to allow grease to leave the gap (5) only at the second side (8) of the bearing assembly (1); - a third ring (11) connected to the outer ring (3) extending radially toward the axis (A) at the second side (8) so that it has a portion facing the inner ring (4) and the lip seal (10); - a second hermetic seal (12) connecting the third ring (11) to the inner ring (3) for creating a collection chamber (13) for grease leaking from the gap (5) through the lip seal (10) at the second side (8); - a discharge circuit obtained in the third ring (11) and facing the collection chamber (13) for discharging the grease collected in the collection chamber (13) outside the bearing assembly (1).
  2. The bearing assembly as claimed in claim 1, wherein the discharge circuit comprises an annular groove (14) obtained in the third ring (11), the annular groove (14) being on one side facing the collection chamber (13) and on another side connected to discharge openings obtained in the ring (11) facing the outside of the bearing assembly (1).
  3. The bearing assembly as claimed in claim 2, wherein a piston device (15) is provided movable in the groove (14) to force grease from the groove (14) of the collection chamber (13) to the discharge openings.
  4. The bearing assembly as claimed in claim 3, wherein the discharge openings are tangential to the groove (14).
  5. The bearing assembly as claimed in claim 4, wherein the piston device (15) comprises a piston (16) and two cables (17) connected by opposite parts of the piston (16) and extending outside the tangential discharge openings for manual actuation of grease discharge.
  6. The bearing assembly as claimed in claim 2, wherein the discharge openings (18) are radial and connected to radial discharge ducts (19) obtained in the third ring (11) and connected, in turn, to the groove (14).
  7. The bearing assembly as claimed in claim 6, in which deflectors (20') are provided in the gap (14) at the radial discharge ducts (19) to deflect grease to the radial discharge ducts (19).
  8. The bearing assembly as claimed in claim 6, in which partitions (21') are provided in the gap (14) to divide the gap (14) into sub-chambers in which each chamber is connected to at least a radial discharge duct (18).
  9. The bearing assembly as claimed in any of claims 6 to 8, where removable plugs are provided at the radial discharge openings (18).
  10. The bearing assembly as claimed in any one of claims 6 to 8, wherein movable plugs are provided in the gap (14) to selectively open and close the connection between the gap (14) and the radial discharge ducts (19).
  11. A wind turbine (20) comprising a first body and at least one second body extending along an axis (A) and coupled to the first body in a rotatable manner with respect to the axis (A); wherein the second body is coupled to the first body in a rotatable manner by a bearing assembly (1) as claimed in any one of the preceding claims wherein the second body and the first body are coupled by opposite portions of the bearing assembly (1) to the third ring (11) and the inner ring (3), respectively.
  12. The wind turbine (20) as claimed in claim 11, in which, respectively, the first body is a hub (21) and the second body is a blade (22) rotating around the axis (A) to change the wing area of the blade (22) to be exposed to the wind.
  13. A cable transport system comprising a hauling cable, at least one passenger transport unit coupled to the hauling cable, a pulley coupled to the cable to haul the cable rotatably around the A-axis, a pulley support structure; wherein the pulley is rotatably coupled to the support structure via a bearing assembly (1) as claimed in any one of the preceding claims 1 to 10; wherein the pulley and the support structure are coupled by opposite parts of the bearing (1) to the third ring (11) and the inner ring (3), respectively.

Description

Cross-Reference to Related Applications This Patent Application claims priority from Italian Patent Application No. 102022000012773 filed on June 16, 2022 Technical Field The technical field of this invention concerns heavy mechanics systems, such as, preferably, wind turbines and cable transportation systems, but also earthmoving machines, cranes, lifters, etc., wherein there are rotating elements connected to fixed parts by means of special bearings. In the details of this invention, such bearings are lubricated with grease and, in this context, this invention will deal with the issue of how to optimise the periodic steps for replacing the lubrication grease of these components. State of the Art In the context of heavy mechanics, as in wind turbine and cable transportation systems, it is known to use bearings lubricated with grease to connect moveable parts to fixed parts. To retain the grease in the coupling portions and to be able to, in any case, replace it when necessary, it is known to provide the above-mentioned bearings with special seals. Referring to the axis of the ring-shaped bearing, the grease is housed in the axial gap between the inner and outer rings and, at the opposite sides of this in the gap, there is a hermetic seal on one side and a lip seal on the other. As known, the lip seal is configured so that the grease leaks out in a controlled way during normal operation of the bearing, as well as during the steps of topping up or changing the grease. Obviously, the used-up grease that has leaked out of the lip seal must be removed periodically to avoid the grease penetrating the other points of the bearing from here. In large mechanic systems, such as, for example, a cable car system and a wind turbine, these cleaning operations for the used-up leaked grease, as described above, are not very convenient to perform given also the height at which one must operate and, sometimes, it also requires the dismantling of some components. Obviously, said operation involves high costs and long maintenance times. There is, therefore, the need today to have a new and inventive solution to the problem of removing the used-up, leaked grease as described above in the bearing. DE102013200356 discloses a bearing assembly grease-lubricated according to the preamble of claim 1. Description of the Invention The purpose of this invention is, thus, to provide a bearing assembly that reduces the drawback of the prior art described in the preceding chapter regarding the problem of removing the used-up grease. This invention provides, as a starting point, a known configuration of a grease-lubricated bearing, in particular for wind turbines or cable transportation systems, wherein this bearing is annular shaped around an axis A and comprises: an outer ring;an inner ring, wherein between the inner ring and outer ring an axial gap is provided filled with lubrication grease and extending from a first side to a second side of the bearing assembly;at least one rolling body housed in the gap to allow relative rotation of the rings around the axis A;a first hermetic seal and a lip seal respectively at the first and second side of the gap to allow grease to leak out the gap only at the second side of the bearing assembly. The configuration described up to here corresponds to the current state of the art (that is also represented in Figure 2) and, thus, the person skilled in the art does not require other details to fully understand the implementation thereof. Starting from this known configuration, this invention proposes, in an inventive way, to provide the bearing assembly with an additional element in the form of a sealing-holding ring (claimed as the third ring 11), which will define, with a specific seal, a closed collection chamber for grease downstream of the lip seal. In addition, this third ring is provided with a series of channels, ducts, openings, and grooves for creating a discharge circuit configured to carry, in a controlled manner, the grease from the collection chamber outside the bearing assembly. In detail, the new elements that this invention thus involves are: the above-mentioned third ring connected to the outer ring of the bearing wherein this third ring has a radial extension towards the axis A at the second side of the bearing to create a portion overhanging and facing (spaced) the inner ring and the lip seal;a second hermetic seal (extending basically axially) that connects the third ring to the inner ring so as to create a collection chamber for the grease leaked from the gap through the lip seal at the second side; thus, the collection chamber is delimited by a radial face of the inner ring, the second hermetic seal, the radial face of the third ring facing the inner ring, the portion of the axial face of the outer ring that extends axially beyond the inner ring and the lip seal in the mouth of the gap;a discharge circuit obtained in the third ring with at least one inlet facing the collection cham