FR3066792A1 - BEARING LUBRICATION DEVICE - Google Patents

Abstract

The invention relates to a bearing for rolling elements comprising a wall with a cylindrical outer surface and a cavity intended to contain a lubricating fluid, said cavity opening outwards through at least one opening allowing the lubricating fluid to be admitted into the cavity. , said bearing further comprising a device for circulating a fluid putting in fluid communication the cavity and the outside thereof to ensure the distribution of a film of fluid on the outer surface of the bearing wall, characterized in the circulation device comprises at least one hollow insert passing through the cavity and extending substantially diametrically therein, said hollow insert having an outlet orifice at the outer surface of the bearing wall and at least one intake hole in the vicinity of the bottom of the cavity opposite this outlet and thus communicating said bottom of the cavity and the outside of the landing.

Description

BEARING LUBRICATION DEVICE

GENERAL TECHNICAL FIELD AND PRIOR ART The invention relates generally to the bearings, and more particularly to their lubrication. The invention advantageously finds application for gear trains, for example planetary trains, in particular on planetary gear satellites.

It also relates to turbomachines equipped with such gear trains or such bearings. The invention can also find its application on a rolling bearing.

A planetary train conventionally comprises, as illustrated in FIG. 1, a first planetary 1, a satellite 2 mounted in rotation on a satellite carrier 3, and a second planetary 4 (or crown in this precise case). The reduction (or multiplication) ratio of the rotation speeds depends on the observed elements and the fixed elements among the planets and the satellite carrier.

The mobile elements are generally assembled on the fixed elements or having a different speed of rotation by interposing between them bearings 5, an example of which is shown in FIG. 2, making it possible to limit the friction between the satellite carrier 3 and the satellite 2.

This reduction in friction limits the energy losses in the mechanism and improves the overall mechanical efficiency of the gear train.

In order to further reduce friction, these bearings can be lubricated, or include a device 6 for circulating a lubrication fluid.

With reference to FIG. 3, a flow of lubrication fluid therefore conventionally circulates from a cavity 7 situated inside the bearing 5 towards its outer surface 8 by following pipes 9 produced through the wall 10 of the bearing 5.

In some cases, the circulation of the lubrication fluid is ensured by a pumping system.

When the pump encounters an anomaly, the fluid circulation system is no longer supplied normally. It is necessary to provide lubrication of the various elements for a fixed period, corresponding for example to an emergency stop of the gear train, the ignition of an auxiliary pumping system or the restarting of the main pumping system to avoid degradation of the bearings.

During this period, only the fluid present in the gear train at the time of the pumping system failure makes it possible to ensure the lubrication function of the bearings.

In order to maximize this quantity of fluid, it is known to produce bearings 5 comprising chambers serving as oil reservoir 11 ensuring emergency lubrication in the event of an anomaly in the main lubrication system.

The circulation of this fluid is ensured, in this operating case concerning a satellite bearing of a planetary gear train, by centrifugal effect. Indeed, in the case where the planet carrier is rotating, the fluid contained in the bearing of the satellite is subjected to a centrifugal force due to the eccentricity of the satellite relative to the axis of rotation of the planet carrier.

The fluid is therefore found held against a wall of the chamber located on the side opposite the axis of rotation of the planet carrier.

This centrifugal force allows the fluid to pass through the main pipes 9 so as to ensure the lubrication function of the bearing.

It is known to produce secondary pipes 12, which allow a lower fluid injection rate than that of the main pipe 9.

In order to increase the autonomy of the fluid reserve in the event of a breakdown of the pumping system, it is known to adopt a certain configuration of the various pipes so as to prevent the fluid from passing unnecessarily through the main pipe 9 .

The main pipe 9 is generally produced by a hole extending between the external surface 8 of the bearing and one of the eccentric holes 15 made on a partition 14 of the oil tank 11.

Thus, when the oil level is below the level of the eccentric bore 15 comprising a mouth 17 of the main line 9, the oil can only pass through the secondary lines 12, the oil being projected against the wall on the opposite side drilling 15 by centrifugal effect.

The holes 15 made on the partition 14 are produced by inserting the tools into the internal cavities 7 passing through their lateral opening 16, having a diameter smaller than the internal cavity 7.

It is therefore impracticable in these embodiments to maximize the fluid reserve by drilling through the partition 14 at the lowest level of the internal cavity 7.

There is nevertheless a need to increase the reserve of fluid 13 available in the event of a breakdown of the lubrication fluid pumping system.

OVERVIEW OF THE INVENTION

An object of the invention is to increase the reserve of fluid in the bearing in the event of a breakdown of the pumping system.

Another object is to simplify the internal structure of the bearing, and indirectly its manufacturing process and its cost.

Another aim is to lighten the landing.

Another aim is to improve the performance of the lubrication system.

According to one aspect, the invention provides a bearing comprising a wall with a cylindrical external surface and a cavity intended to contain a lubrication fluid, said cavity opening to the outside by at least one opening allowing the admission of the lubrication fluid into the cavity, said bearing further comprising a device for circulating a fluid placing the cavity and the exterior of said cavity in fluid communication to ensure the distribution of a film of fluid on the external surface of the wall of the bearing, characterized in that the circulation device comprises at least one hollow insert passing through the cavity, extending substantially diametrically inside the latter, said hollow insert having an outlet orifice at the level of the external surface of the bearing wall and at least one inlet hole in the vicinity of the bottom of the cavity opposite this outlet orifice and thus putting said bottom of the cavity into communication with the outside interior of the bearing. The insertion of at least one hollow insert into the bearing cavity makes it possible to increase the reserve of fluid in the event of a breakdown while reducing the mass of the bearing and simplifying its manufacturing process.

Indeed, the presence of a hollow insert makes it possible to eliminate the partition partition present in the prior art.

This elimination allows, with equal external dimensions of the bearing, larger internal cavities and therefore an increase in the fluid reserve.

The structure is also lightened.

Also, the use of an insert makes it possible to fetch the fluid in the vicinity of the bottom of the bearing, and without it being necessary to make holes from an intake opening.

The quantity of fluid present in the cavity which serves as a reserve in the event of a breakdown (quantity of fluid beyond the level of the intake hole) is increased.

In addition, during the manufacture of the bearing, the cavity can be produced from a single intake opening, which simplifies manufacture.

Such a device is advantageously supplemented by the following different characteristics taken alone or in combination: - The cavity has a single intake opening; - The bearing is a plain bearing; - The wall of the bearing comprises at least one bore which constitutes a secondary pipe through which fluid is discharged towards the outside, including in configurations where the inlet hole of the insert is no longer supplied; - The drilling opens at the level of the external surface of the bearing in a zone opposite to the inlet hole of the insert; - The bearing has at least two inserts distributed over the length of the cavity; - The insert is held by shrinking on the wall of the bearing; - The wall of the bearing comprises an internal blind bore in which the end of the insert opposite the outlet orifice is received, as well as a through bore which is diametrically opposite to said blind bore and is coaxial therewith; - The insert comprises a stop portion engaged in the blind bore, a centering portion extending in the through bore, the stop portion and the centering portion having a wall thickness greater than the thickness of wall of the portion of the insert extending between said stop portion and said centering portion.

According to another aspect, the invention also proposes a manufacturing method for producing such a bearing, in which, when the bearing is with a single intake opening, the internal surfaces of the cavity are machined from the single lateral opening.

According to another aspect, the invention proposes an epicyclic train comprising such a satellite bearing.

According to another aspect, the invention proposes a turbomachine comprising such a planetary gear train.

PRESENTATION OF THE FIGURES Other characteristics and advantages of the invention will emerge further from the description which follows, which is purely illustrative and not limiting, and must be read with reference to the appended figures in which: - Figure 1 is a 3D representation isometric of a conventional planetary gear train; - Figure 2 is a schematic representation of a sectional profile view of the implementation of a bearing on a satellite carrier; - Figure 3 is a schematic representation of a sectional profile view of a bearing of the prior art; - Figure 4 is a sectional side view of an embodiment of a bearing fitted with inserts according to the invention; - Figure 5 is a schematic representation of a sectional profile view of an insert; - Figure 6 is a sectional side view of another embodiment of a bearing fitted with inserts according to the invention.

DESCRIPTION OF ONE OR MORE MODES OF IMPLEMENTATION AND IMPLEMENTATION

The embodiments described below relate to the case of a bearing 5 of axis X, represented in FIG. 4. The example given is however not intended to be in any way limiting, insofar as the bearing could have various geometrical specifications.

The bearing 5 comprises an internal cavity 7, an external surface 8 and an internal surface 17, a wall 10 and an inlet opening 16 at one of its ends.

In certain embodiments, a toric groove 18 is produced on each of the ends of the bearing 5 so as to increase the flexibility of the bearing 5 and to facilitate assembly.

The grooves 18 make it possible to limit the deformation of the useful surface of the bearing 5, this useful surface being the external surface 8.

In the event of a significant force which can cause a deformation of the bearing, the deformation takes place at the level of the groove 18, the surface of the bearing 5 thus remaining cylindrical.

This behavior also makes it possible not to transmit misalignments to the toothing, when an misalignment of the axes occurs between the planet carrier and the satellite for example.

During normal operation, a lubrication fluid pressurized by a pumping system circulates in the internal cavity 7 passing through the intake opening 16.

This lubrication fluid is directed towards the external surface 8 from the internal cavity 7 by outlet orifices 33 of inserts 19 forming the main pipes 9.

In the embodiment presented in FIG. 5, the inserts 19 have a cylindrical body 22 of variable diameter, and have a hole coaxial 23 to the body 22 or longitudinal and a hole orthogonal 24 to the body 22 or transverse.

The longitudinal bore 23 opens into the transverse bore 24, the transverse bore 24 passing through the insert 19 diametrically and thus producing an inlet hole 32 for fluid.

Additional thicknesses can be produced at the portions of the inserts 19 in contact with the bearing 5, in particular a centering portion 25 and a stop portion 26, a central portion 27 extending between the centering portion 25 and the portion d stop 26.

The centering 25 and stop 26 portions have a wall thickness greater than the central portion 27.

To facilitate their mounting in the bearing 5, the inserts 19 have chamfers 28 at the diameter change zones.

The longitudinal bore 23 may have at its end a conical mouth 29 making it possible to produce a thread in order to cooperate with a tool during a step of dismantling the insert 19, when the insert 19 is damaged or that a an accident during assembly involves dismantling the insert 19, thereby preserving the bearing 5.

In an embodiment shown in FIG. 6, holes are drilled in the wall of the bearing 5 so as to produce secondary pipes 12.

These secondary pipes 12 allow the lubrication fluid to flow from the cavity 7 to the external surface 8 of the bearing 5 when the pumping system fails.

The secondary pipes 12 have in certain embodiments a smaller section than the section of the main pipes 9.

The secondary pipes 12 are generally located in a zone diametrically opposite the inlet holes.

In this way, when the quantity of fluid present in the cavity decreases under the effect of a failure of the pumping system, the fluid no longer passes through the main pipes 9 when the level of fluid no longer reaches the level intake holes.

It therefore borrows only the secondary pipes 12 which have a reduced diameter and therefore limit the circulation of fluid to allow to maintain degraded operation as long as possible.

The relative positioning of the secondary pipes 12 with respect to the intake holes thus makes it possible to maximize the fluid reserve 11. The use of inserts 19 to produce the main pipes 9 also makes it possible to simplify the internal structure of the bearing 5.

Indeed, it is no longer necessary to make the main pipes 9 in the partition, which can therefore be deleted. Consequently, the manufacturing process is reduced, allowing all the internal surfaces to be produced from a single lateral opening 16 of the bearing 5.

The elimination of the central wall 14 also makes it possible to reduce the weight of the bearing 5 in addition to offering a significant gain in volume making it possible to increase the reserve of fluid 11.

The transverse drilling 24 does not need to be carried out in the central wall, it can be positioned as close as possible to the internal surface 17 of the cavity, thus maximizing the oil reserve in the event of damage in the system of pumping.

This change in structure also makes it possible to produce several main pipes 9 so as to provide a better distribution of the lubrication fluid on the external surface 8 of the bearing 5.

Indeed, a pipe made in a wall would involve making several walls in the cavity 7, which would decrease the fluid reserve and increase the mass of the bearing.

In the illustrated embodiment, the bearing 5 comprises two inserts 19 parallel to each other implanted radially in the bearing 5, thus allowing a better distribution of the lubrication fluid on the outer surface 8.

Solutions comprising a single insert 19 or more than two inserts 19 can be envisaged, arranged in a geometry different from the geometry illustrated.

The secondary pipes 12 can be located in a plane different from the plane of the main pipes 9. Despite the slight decrease in the fluid reserve 11 that this arrangement implies, a mouth 30 of the secondary pipe 12 slightly eccentric at the internal surface 17 of the bearing 5 makes it possible to prevent impurities heavier than the fluid from clogging the secondary pipes 12.

The distribution of the inserts 19 forming the main pipes 9 and the holes forming the secondary pipes 12 is chosen to best distribute the oil pressure over the length of the external surface 8, avoiding excessive flow at the ends of the bearing 5. This prevents the fluid from flowing directly to the outside, which would reduce the lubrication effect.

The inserts 19 are assembled to the bearing 5 in through holes 20 made through the wall 10 of the bearing, these holes 20 being extended by blind holes 21 coaxial with the through holes 20, the blind holes 21 being made on the internal surface 17 of the level 5.

The stop portion 26 of the inserts 19 is therefore located in the blind holes 21, the centering portion 25 extending in the through holes 20.

In some embodiments, the inserts 19 are mounted in the blind holes 21 and the through holes 20 by shrinking.

One embodiment proposes a hooping when hot, the withdrawal of the material from the bearing 5 when cold ensuring the clamping force performing the assembly between the insert 19 and the bearing 5.

It is however conceivable to use other assembly methods, such as brazing, bonding, threaded assembly, or any technical solution allowing a fixed connection to be obtained between the inserts 19 and the bearing 5.

The assembly method by hot shrinking involves significant pressure levels in the inserts 19. The thickness of the wall of the insert 19 at the stop portion 26 and at the centering portion 25 is therefore sized to limit the internal pressure levels in the inserts 19 due to the shrinking pressure.

Claims (12)

1. Bearing (5) comprising a wall (10) with external cylindrical surface (8) and a cavity (7) intended to contain a lubrication fluid, said cavity (7) opening to the outside through at least one opening (16 ) authorizing the admission of the lubrication fluid into the cavity (7), said bearing further comprising a circulation device (6) of a fluid placing the cavity (7) in fluid communication with the outside of the bearing to ensure the distribution of a film of fluid on the external surface (8) of the wall (10) of the bearing, characterized in that the circulation device (6) comprises at least one hollow insert (19) passing through the cavity (7) in extending substantially diametrically inside thereof, said hollow insert (19) having an outlet orifice (33) at the level of the external surface (8) of the wall (10) of the bearing and at least one hole intake (32) near the bottom of the cavity (7) opposite this outlet (33) and thus putting if in communication said bottom of the cavity (7) and the outside of the bearing. 2. Bearing according to claim 1, characterized in that the cavity (7) has a single intake opening (16). 3. Bearing according to one of the preceding claims, characterized in that said bearing (5) is a smooth bearing. 4. Bearing according to one of the preceding claims, characterized in that the wall (10) of the bearing comprises at least one secondary pipe (12) through which the fluid is discharged towards the outside including in configurations where the hole inlet (32) of the insert (19) is no longer supplied. 5. Bearing according to one of the preceding claims, characterized in that the secondary pipe (12) opens at the external surface (8) of the bearing in a zone opposite to the intake hole (32) of the insert ( 19). 6. Bearing according to one of the preceding claims, characterized in that the bearing comprises at least two inserts (19) distributed over the length of the cavity (7). 7. Bearing according to one of the preceding claims, characterized in that the insert (19) is held by shrinking on the wall (10) of the bearing. 8. Bearing according to one of the preceding claims, characterized in that the wall (10) of the bearing comprises a blind bore (21) inside which is received the end of the insert (19) opposite the orifice outlet (33), as well as a through hole (20) which is diametrically opposite to said blind hole (21) and is coaxial with it. 9. Bearing according to the preceding claim, characterized in that the insert (19) comprises a stop portion (26) engaged in the blind bore (21), a centering portion (25) extending in the through bore (20), the stop portion (26) and the centering portion (25) having a wall thickness greater than the wall thickness of the portion of the insert extending between said stop portion ( 26) and said centering portion (25). 10. Manufacturing process for producing a device according to one of claims 2 to 9, characterized in that all the internal surfaces of the cavity (7) are produced from the single lateral opening (16). 11. planetary gear train comprising at least one bearing (5) according to one of claims 1 to 9. 12. Turbomachine comprising a planetary gear train according to claim 11.