Improved sealing device for rotating machinery.

Abstract

Improved sealing device for rotating machinery. Rotating machinery (1) comprising a first movable assembly (10) and a second movable assembly (20), in which an interface between the first assembly (10) and the second assembly (20) comprises a housing (4) provided with a first sealing element (40), in which a second sealing element (6) is positioned at an interface between the first assembly (10) and the second assembly (20), adapted to allow oil to pass from the internal volume (2) to the housing (4) when the pressure difference between the internal volume (2) and the housing (4) is less than a pressure threshold value, and to prevent oil from passing from the internal volume (2) to the housing (4) when the pressure difference between the internal volume (2) and the housing (4) exceeds said pressure threshold value.characterized in that a through conduit (50) is formed in the first assembly (10) or in the second assembly (20) so as to connect the housing (4) to the internal volume (2) or to the external environment, said through conduit (50) being closed by a plug (52). Figure for the abbreviation: Fig. 2.

Description

Title of the invention: Improved sealing device for rotating machine. Technical field

[0001] The present disclosure relates to an improved sealing device for a rotating machine, and more specifically to a sealing protection device against pressure peaks. Prior art

[0002] The use of rotating machines in different environments poses problems in terms of sealing. Indeed, a recurring problem is to prevent the admission of impurities into an internal volume of the casing of the rotating machine.

[0003] Different sealing structures have been proposed to ensure good sealing between the internal volume of the rotating machine and the external environment. However, the known solutions remain problematic in terms of reliability, particularly over time.

[0004] A first assembly consists of placing a single sealing element ensuring insulation between the ambient environment and the internal volume of the casing. However, in the event of a rise in pressure in the casing, the sealing element may be expelled from its housing, or destroyed, for example by tearing or by seizure of the surfaces in sliding contact in the case of metal seals because the bearing force between two sliding parts increases. This results in high friction and a loss of efficiency in the case of metal seals. Such rises in casing pressure are due, for example, to the start-up of a cold rotating machine.Pressurized oil enters the machine housing through the usual internal leaks in these machines, while the crankcase oil cannot easily escape through the crankcase drain pipe, which is still filled with cold oil and therefore generates very high pressure losses due to the high viscosity of the cold oil. Such operations quickly destroy the sealing element. In particular, if the pressure rises in the machine housing, the contact force between sliding parts of the sealing element increases, and seizure or extrusion may follow in the case of a soft sealing element, which destroys the sealing element. Components of the sealing element can also be destroyed by the pressure.

[0005] Alternatively, the anti-pollution sealing elements providing insulation between the ambient environment and the internal volume of the casing can be arranged in dedicated housings, these housings themselves being isolated from the internal volume of the casing comprising the rotating machine, for example a rotating machine, by a casing seal commonly referred to as absolute sealing, combining a dynamic sealing element such as a lip seal with a dynamic sealing element resistant to possible pressure peaks, for example an O-ring coupled to an annular element. However, such an assembly thus defines a closed chamber between the axial sealing elements and the casing sealing elements. However, such a closed chamber poses a problem in terms of lubrication. Indeed, the housing comprising the axial sealing elements being totally isolated from the internal volume of the casing by the casing seal, this housing is not continuously lubricated, particularly in the event of loss of lubricant over time, or deterioration of its characteristics, and also during the first commissioning of the rotating machine.However, a lack of lubrication can lead to rapid destruction of the sealing elements, particularly due to seizure or extrusion due to lack of oil. The commonly proposed solutions consist of inserting a predetermined volume of oil into this housing, this volume of oil must necessarily be replaced at regular intervals. The housing must also have sufficient volume, which makes the rotating machine less compact. However, it is understood that such solutions are highly restrictive and require dedicated maintenance operations.

[0006] This presentation thus aims to respond at least partially to these problems. Statement of the invention

[0007] To this end, the present disclosure relates to a rotating machine comprising a first assembly and a second assembly movable in rotation relative to each other along an axis of rotation, said rotating machine comprising a casing defining an internal volume, in which an interface between the first assembly and the second assembly comprises a housing provided with a first dynamic sealing element ensuring the sealing of the internal volume with respect to the external environment, wherein a second dynamic sealing element is positioned at an interface between the first assembly and the second assembly, between the internal volume and the housing, said second sealing element being adapted to allow passage of oil from the internal volume to the housing when the pressure difference between the internal volume and the housing is less than a pressure threshold value so as to allow lubrication of the first sealing element by the fluid coming from the internal volume, and not to allow passage of oil from the internal volume to the housing when the pressure difference between the internal volume and the housing exceeds the threshold value is greater than said pressure threshold value, characterized in that a through conduit is formed in the first assembly or in the second assembly so as to connect the housing to the internal volume or to the external environment, said through conduit being closed by a plug.

[0008] According to one example, the through conduit is formed in a casing of the rotating machine or in a shaft of the rotating machine.

[0009] According to one example, the rotating machine comprises a second through conduit formed in the first assembly or in the second assembly so as to connect the housing to the internal volume or to the external environment, said through conduit being closed by a plug.

[0010] According to one example, the second sealing element comprises a passage adapted to close when the pressure difference between the internal volume and the housing exceeds the threshold value, for example when the pressure difference between the internal volume and the housing exceeds a threshold value, typically 0.1, 0.2 or 0.5 bar.

[0011] According to one example, the second sealing element is adapted to, when the pressure difference between the internal volume and the housing is less than or equal to the pressure threshold value, allow oil to pass from the housing to the internal volume, and when the pressure difference between the internal volume and the housing is greater than the pressure threshold value, isolate the housing from the internal volume.

[0012] According to one example, the first sealing element is an axial seal comprising a first metal ring, a second metal ring, a first elastomer ring and a second elastomer ring, the first metal ring and the second metal ring being mounted to bear against each other in an axial direction defined by the axis of rotation, the first elastomer ring being interposed between the first metal ring and a wall of the first assembly, and the second elastomer ring being interposed between the second metal ring and a wall of the second assembly.

[0013] According to one example, the second sealing element comprises an O-ring.

[0014] The second sealing element then typically comprises a ring on which the O-ring is mounted.

[0015] The ring then typically comprises a bore, adapted to allow fluid to pass when the pressure difference between the internal volume and the housing e is less than or equal to said pressure threshold value, and not to allow fluid to pass when the pressure difference between the internal volume and the housing is greater than said pressure threshold value.

[0016] According to one example, the second sealing element is positioned between two rolling elements providing the relative rotational movement between the first assembly and the second assembly.

[0017] According to one example, the second sealing element is made in a single piece.

[0018] According to one example, the second sealing element is interposed between two surfaces facing in the axial direction defined by the axis of rotation.

[0019] According to one example, the second sealing element is interposed between two surfaces facing each other in the radial direction relative to the axis of rotation.

[0020] According to one example, the pressure threshold value is equal to 0.5 bar, or 0.2 bar, or even 0.1 bar.

[0021] The rotating machine is for example a hydraulic machine comprising a cylinder block provided with a plurality of housings extending radially relative to the axis of rotation in which cylinders are arranged, and a multi-lobe cam surrounding the cylinder block, or may be a braking device.

[0022] According to one example, the rotating machine is a hydraulic machine comprising a cylinder block provided with a plurality of housings extending radially relative to the axis of rotation in which cylinders are arranged, and a multi-lobe cam surrounding the cylinder block.

[0023] Method of assembling a rotating machine as defined above, in which: - we provide a first set and a second set - a rolling bearing is provided positioned in an internal volume between the first assembly and the second assembly, so that the first assembly and the second assembly are rotatable relative to each other along an axis of rotation, - a first dynamic sealing element is provided at an interface between the first assembly and the second assembly comprising a housing, said first dynamic sealing element ensuring the sealing of the internal volume with respect to the external environment, - a second dynamic sealing element is provided positioned at an interface between the first assembly and the second assembly, between the internal volume and the housing, said second sealing element being adapted to allow passage of oil from the internal volume to the housing when the pressure difference between the internal volume and the housing is less than a pressure threshold value so as to allow lubrication of the first sealing element by the fluid coming from the internal volume, and not to allow passage of oil from the internal volume to the housing when the pressure difference between the internal volume and the housing exceeds the threshold value is greater than said pressure threshold value, - a volume of oil is injected into the housing via a conduit formed in the first assembly or in the second assembly and opening into the housing, - the conduit is closed using a plug, - components are supplied and assembled so as to form a rotating machine between the first set and the second set, one among the first set and the second set comprising a housing, and the other of the first set and the second set comprising a shaft.

[0024] According to one example, the conduit connects the housing to the internal volume, and in which the injection of the volume of oil into the housing and the sealing of the conduit are carried out prior to the assembly of the components forming the rotating machine.

[0025] According to one example, the conduit connects the housing to an external volume, and in which the injection of the volume of oil into the housing and the sealing of the conduit are carried out following the assembly of the components forming the rotating machine. Brief description of the drawings

[0026] The invention and its advantages will be better understood upon reading the detailed description given below of different embodiments of the invention given as non-limiting examples.

[0027] [Fig-1] [Fig.l] shows an overview of an example of a rotating machine according to one aspect of the invention.

[0028] [Fig.2] [Fig.2] shows an example of a rotating machine according to one aspect of the invention.

[0029] [Fig.3] [Fig.3] is a detailed view of a sealing element according to one aspect of the invention.

[0030] [Fig.4] [Fig.4] is a detailed view of a sealing element according to one aspect of the invention.

[0031] [Fig.5] [Fig.5] is a detailed view of a sealing element according to one aspect of the invention.

[0032] [Fig.6] [Fig.6] shows an example of a rotating machine according to one aspect of the invention.

[0033] [Fig.7] [Fig.7] shows an example of a rotating machine according to one aspect of the invention.

[0034] Throughout the figures, the elements in common are identified by identical numerical references. Description of the embodiments

[0035] An exemplary embodiment of the invention is described below with reference to Figures 1 to 5.

[0036] [Fig.l] shows a sectional view of a rotating machine 1, typically a hydraulic machine with radial pistons and a multi-lobe cam. By hydraulic machine, we typically mean a hydraulic motor or a hydraulic pump, these devices typically having a reversible operation. The rotating machine can also be a braking device, for example comprising a stack of discs formed of two subsets of linked discs each to one of the rotor and the stator according to a structure and operation well known to those skilled in the art. The rotating machine 1 comprises a distributor cover 110, a supply distributor 112, an assembly commonly referred to as a hydrocouple comprising a cylinder block 114 and pistons 116 equipped with a roller 118, and a multi-lobe cam 120, a shaft 122 and a bearing 124 consisting of a set of bearings, and a bearing cover 126. The shaft 122 is mechanically connected to the cylinder block 114 to transmit a rotational movement resulting from a torque applied to the shaft 122 or from sliding of the pistons 116 in contact with the multi-lobe cam 120. The distributor cover 110 comprises supply ducts for the suction and discharge of the rotating machine 1.The suction and discharge ducts, the distributor ducts and the piston chambers of the cylinder block are connected to a hydraulic power circuit, which transmits the hydraulic motive power. For example, they are connected to the supply and return branches, or high pressure HP and low pressure LP branches of a closed-loop hydraulic circuit, or to the supply by a power pump and to the return to a reservoir for an open-loop hydraulic circuit. In the example illustrated, the distributor cover 110, the cam 120 and the bearing cover 126 define a casing of the rotating machine 1. More generally, the casing of the hydraulic machine designates the different elements which delimit at least partially an internal volume comprising in particular the cylinder block 114.

[0037] The volume contained in the casing around the various aforementioned elements represents the internal volume of the rotating machine 1. It is represented by hatching in [Fig.l]. It is isolated from the hydraulic power circuit (represented by dotted lines) by the seals of the pistons 116 and the distributor 112 in a manner known to those skilled in the art. The internal volume of the rotating machine 1 receives an oil flow coming from the internal leaks of the rotating machine 1 from the power circuit, and it is typically connected by a drain to a reservoir to evacuate this oil flow, so that the pressure in the internal volume of the rotating machine 1 remains substantially equal to the pressure of said reservoir, which is typically equal to or close to atmospheric pressure.

[0038] [Fig. 2] shows a partial sectional view of a rotating machine 1. The rotating machine 1 comprises a first assembly 10 and a second assembly 20 which are movable in rotation relative to each other along an axis of rotation XX. In the following description, the designations “radial” and “axial” are defined relative to the axis of rotation XX unless otherwise stated.

[0039] In the example illustrated, the rotational movement is provided by rolling elements, here conical bearings 32 and 34 forming a bearing 30. The machine rotating 1 comprises an internal volume 2 in which different components 3 of the rotating machine are arranged depending on its nature, for example a radial piston or axial piston hydraulic motor, a radial piston or axial piston hydraulic pump, a braking system, or any other device.

[0040] The first assembly 10 and the second assembly 20 designate the different components of the rotating machine 1. For example, one of these assemblies may comprise a shaft, a cylinder block and a distributor of a hydraulic machine, while the other of these assemblies may comprise a multi-lobe cam. The first assembly 10 and the second assembly 20 may comprise braking means, for example discs adapted to prevent the relative rotational movement of the first assembly 10 with respect to the second assembly 20 under the effect of friction between said discs.

[0041] The internal volume 2 of the rotating machine is isolated from the external environment via a first sealing element 40 arranged in a housing 4. The housing 4 is connected to the external environment via a conduit 5, formed by a gap between the first assembly 10 and the second assembly 20. In the example illustrated, the first sealing element 40 is an axial seal, or ice seal, commonly referred to as a duo-cone seal.

[0042] The first sealing element 40 here comprises a first metal ring 41 and a second metal ring 43, made of metal material, and which are typically symmetrical with respect to a plane extending radially with respect to the axis of rotation XX. The first sealing element 40 also comprises a first elastomer ring 42 and a second elastomer ring 44, made of elastomer material.

[0043] The first metal ring 41 and the second metal ring 43 bear against each other in the axial direction defined by the axis of rotation XX.

[0044] The first elastomer ring 42 is mounted to bear against the first metal ring 41 on the one hand, and against a partition 14 of the first assembly 10.

[0045] The second elastomer ring 44 is mounted to bear against the second metal ring 43 on the one hand, and against a partition 24 of the second assembly 20.

[0046] The first elastomer ring 42 and the second elastomer ring 44 are typically positioned radially outwardly relative to the first metal ring 41 and the second metal ring 43. The first metal ring 41 and the second metal ring 43 compress the first elastomer ring 42 and the second elastomer ring 44 against the partitions 14 and 24 respectively of the first assembly 10 and the second assembly 20, and thus ensure a sealed connection.

[0047] The first metal ring 41, the second metal ring 43 as well as the partitions 14 and 24 respectively of the first assembly 10 and of the second assembly 20 are typically formed in such a way that the first elastomer ring 42 and the second elastomer ring 44 tend to move the first metal ring 41 and the second metal ring 43 against each other in the axial direction defined by the axis of rotation XX.

[0048] As indicated previously, a problem with this type of assembly concerns the lubrication of the first sealing element 40. Indeed, in conventional structures, the housing 4 is typically isolated from the internal volume of the casing 1 by a seal described as absolute, which commonly comprises a dynamic seal coupled with a reinforced seal adapted in particular to withstand possible pressure peaks, for example a lip ring. However, such an assembly completely isolates the housing 4 from the internal volume of the casing 1, which therefore requires providing lubrication from the design stage, for example by inserting a predetermined quantity of oil into the housing 4. However, this requires regular maintenance operations in order to reintroduce oil into the housing 4, since the oil gradually escapes to the external environment.Furthermore, such structures pose a problem in the event of a pressure peak in the internal volume of the casing 1, which can then lead to destruction of the sealing element positioned in the housing 4.

[0049] The structure proposed in the present disclosure proposes to position not an absolute seal between the internal volume 2 and the housing 4, but a second sealing element 6. The second sealing element 6 proposed being adapted to allow a passage of fluid from the internal volume 2 to the housing 4 when the pressure in the internal volume 2 is less than or equal to a pressure threshold value, and to isolate the housing 4 from the internal volume 2 when the pressure difference between the internal volume 2 and the housing 4 is greater than said pressure threshold value, and thus not to allow a passage of fluid from the internal volume 2 to the housing 4 when the pressure difference between the internal volume 2 and the housing 4 is greater than said pressure threshold value. The second sealing element 6 thus has a function of a calibrated valve, or of a nozzle with two flow directions.

[0050] The passage in the second sealing element can also operate in the opposite direction, which allows oil to pass from the housing to the internal volume when the pressure rises in the internal volume, in particular in the event of heating. Such operation in both flow directions is not detrimental to the lubrication of the housing 4.

[0051] The second sealing element 6 thus makes it possible to produce a calibrated flow of oil from the internal volume 2 to the housing 4 when the pressure difference between the internal volume 2 and the housing 4 is less than or equal to a predetermined pressure threshold value. The second sealing element 6 thus typically has a passage, allowing a circulation of fluid between the internal volume 2 and the housing 4. as long as the pressure is less than or equal to a pressure threshold value, and closing when the pressure difference between the housing 4 and the internal volume 2 exceeds the pressure threshold value, then isolating the internal volume 2 from the housing 4. More generally, the second sealing element 6 is calibrated so that the flow rate of fluid that can pass into the housing 4 does not cause too great a pressure rise in the housing 4. According to one example, the second sealing element can be calibrated so as to allow a pressure rise of the order of 0.2 bar in the housing 4, causing it to go from a pressure of 3 bar to a pressure of 3.2 bar, in the case where 3 bar is the pressure value in the housing 4 and in the internal volume 2 before a pressure peak in the internal volume 2.

[0052] This function thus makes it possible to ensure continuous lubrication of the housing 4, while protecting the first sealing element 40 against pressure peaks within the internal volume 2. Indeed, in the event of a pressure peak within the internal volume 2, the second sealing element 6 is not open, and then behaves as an absolute seal, preventing excessively high pressure from reaching the housing 4, which could cause damage to the first sealing element 40.

[0053] The pressure threshold value is for example between 2.5 and 3.5 bar, or more precisely between 3 and 3.2 bar. More generally, operation in passing mode or not may depend on a pressure difference on either side of the second sealing element 6, for example when the pressure difference is greater than or equal to 0.5 bar, or greater than or equal to 0.2 bar, or even greater than or equal to 0.1 bar.

[0054] In the opposite direction, when the pressure in the internal volume 2 does not exceed the pressure threshold value, the second sealing element 6 allows fluid to pass. When heating occurs in the housing 4, this pressure increase is slow, and oil flows towards the internal volume 2 before a pressure peak is created. In this way, the pressure in the housing 4 does not exceed the pressure of the internal volume 2 as long as the latter is below the pressure threshold. There is no possibility of pressure build-up in the housing 4 by itself. The risk of destruction of the first sealing element 40 or of oil ejection by pressure build-up in the housing 4 is also eliminated.

[0055] The second sealing element 6 can for example be positioned between two rolling elements forming a rolling bearing 30 of the rotating machine 1, between the rolling bearing 30 and the housing 4, or between the internal volume 2 and the rolling bearing 30.

[0056] It is understood, however, that the structure as proposed makes it possible to achieve continuous lubrication of the housing 4 during operation of the rotating machine. However, initial lubrication is necessary in order to ensure lubrication when the rotating machine is first put into service.

[0057] The proposed structure thus comprises a through conduit formed in the first assembly 10 or in the second assembly 20 and opening into the housing 4.

[0058] [Fig. 2] thus presents different embodiments for such a through conduit. The reference 50 generally designates a through conduit formed in the first assembly 10 or in the second assembly 20 and opening into the housing 4, and by a plug 52 adapted to close this conduit 50. The different embodiments will be identified by a letter following these references. More generally, the conduit 50, or where appropriate the conduits 50, is formed in a structural part defining the housing 4.

[0059] According to one example, the through conduit 50a can for example be formed in the first assembly 10, and open into the internal volume 2 of the rotating machine 1. The through conduit 50a thus connects the internal volume 2 of the rotating machine 1 to the housing 4.

[0060] According to another example, the through conduit 50b can for example be formed in the first assembly 10, and open outside the first assembly 10. The through conduit 50b thus connects the external environment to the housing 4.

[0061] According to another example, the through conduit 50c can for example be formed in the second assembly 20, and open outside the second assembly 20. The through conduit 50b thus connects the external environment to the housing 4.

[0062] The through conduit 50 is typically formed in a casing segment of the rotating machine 1. Alternatively, it may for example be formed in the shaft of the rotating machine 1.

[0063] Exemplary embodiments of the second sealing element 6 are now described with reference to FIGS. 3, 4 and 5. The two functions of the second sealing element 6, namely a sealing function and a fluid passage function, are here performed by the same parts.

[0064] These figures show the second sealing element 6, which is here composed of a ring 61 and an O-ring 63. The second sealing element 6 is positioned in a groove 7 formed at an interface between the first assembly 10 and the second assembly 20. The groove 7 can extend radially or axially relative to the axis of rotation XX. The examples illustrated in Figures 3, 4 and 5 show grooves extending radially relative to the axis of rotation XX. It is understood, however, that the operation for an axial groove is similar. A structure having an axial groove will be presented below. The groove 7 is interposed between the internal volume 2 and the housing 4.

[0065] The ring 61 typically forms a ring around the axis of rotation XX. It may have a rectangular section (as visible in [Fig.3]), or have a rectangular section with a protuberance 64 adapted to come into contact with a wall of the first set 10 or second set 20 (as visible in [Fig.5]). One or more holes 62 are made in the ring 61, these holes 62 being adapted to allow a passage of fluid through the ring 61, and therefore form the passage mentioned above for the second sealing element 6.

[0066] The ring 61 has a thickness strictly greater than the spacing between the first assembly 10 and the second assembly 20 around the groove 7, in the axial direction or in the radial direction depending on the orientation of the groove 7.

[0067] In the example illustrated, the first assembly 10 and the second assembly 20 are spaced apart by a distance E1 on either side of the groove 7, radially relative to the axis of rotation XX. The ring 61 thus has a thickness E2 in the radial direction, strictly greater than E1, so that the ring 61 cannot come out of the groove 7. The groove 7 itself has a radial dimension strictly greater than E2, so as to allow the ring 61 and the O-ring 63 to be housed therein.

[0068] The O-ring 63 may have a circular, oval, or any other cross-section. In the examples shown in FIGS. 3, 4 and 5, the O-ring 63 has a circular cross-section and is positioned around the ring 61, i.e. it is in contact with the ring 61 and surrounds it from the outside, radially relative to the axis of rotation XX.

[0069] [Fig.4] illustrates the effect of a pressure peak in the internal volume 2.

[0070] The effect of the pressure peak on the various elements of the second sealing element 6 is shown diagrammatically by arrows. As can be seen in this figure, the O-ring 63 is then pressed against an axial wall of the groove 7, here the wall of the groove 7 opposite the internal volume 2. The increase in pressure within the groove 7 also causes the ring 61 to be crushed under the effect of the pressure and under the effect of the O-ring 63 which compresses the ring 61.

[0071] This crushing of the ring 61 causes a deformation of the ring 61 which thus closes the holes 62 when the pressure is higher than the pressure threshold value, which therefore prevents the passage of fluid through the second sealing element 6.

[0072] It is also understood that the operation is reversible; an identical function is performed in the event of a pressure increase in the housing 4 relative to the internal volume 2. The second sealing element 6 is then adapted to, when the pressure in the housing 4 is less than or equal to the pressure threshold value (or when the pressure difference between the housing 4 and the internal volume 2 exceeds a threshold value), allow fluid to pass from the housing 4 to the internal volume 2, and when the pressure in the housing 4 is greater than the pressure threshold value, isolate the housing 4 from the internal volume 2, which makes it possible to prevent the penetration of impurities into the internal volume 2.

[0073] [Fig. 6] shows a variant of the embodiment already described with reference to [Fig. 2]. The sealing between the first assembly 10 and the second assembly 20 is ensured by absolute sealing and by a second sealing element 6 as defined previously.

[0074] In this exemplary embodiment, an absolute seal 8 is formed between the housing 4 and the internal volume 2, at the interface between the first assembly 10 and the second assembly 20. This absolute seal 8 isolates the housing 4 from the internal volume 2, and prevents any passage of fluid between these two volumes through this seal.

[0075] The second sealing element 6 is positioned in a bypass duct 60 formed in the first assembly 10 or in the second assembly 20, and thus makes it possible to ensure a passage of fluid in the manner of a calibrated valve or a nozzle with two flow directions as already described previously.

[0076] The operation is identical to the operation already described with reference to Figures 2 to 5.

[0077] The bypass conduit 60 may for example be formed of holes opening onto a valve forming an external calibrated flap or a nozzle with two external flow directions, for example a metal valve with 2 tubes, which here constitutes the second sealing element 6.

[0078] This embodiment also shows two examples of embodiments of the through conduit 50 and the plug 52.

[0079] According to one example, the through conduit 50d is formed in the first assembly 10, on an external radial wall of the housing 4. In the example illustrated, the through conduit 50d connects the housing 4 to the internal volume 2 of the rotating machine 1. As a variant, the through conduit 50d could pass through the first assembly 10 so as to open into the external environment.

[0080] According to another example, the through conduit 50e is formed in the second assembly 20, typically in a shaft of the rotating machine. The through conduit 50e extends here from an internal radial wall of the housing 4, and opens into the internal volume 2 of the rotating machine 1. Alternatively, the through conduit 50e could pass through the second assembly 20, typically the shaft, so as to open into the external environment.

[0081] In the same way as for the previous examples, the through conduit 50 makes it possible to inject an initial quantity of lubricant, typically oil, into the housing 4 in order to ensure lubrication for the first commissioning of the rotating machine. Indeed, as described previously, after the first commissioning, the system as proposed ensures continuous lubrication in the housing 4. The through conduit 50 as proposed makes it possible to ensure a first lubrication immediate, and thus to respond to a problem linked to the lack of lubrication for the first commissioning. [Fig.7] presents a variant of the embodiment already described with reference to [Fig.2].

[0082] In this embodiment, the groove 7 is formed along the axial direction of the axis of rotation XX.

[0083] The second sealing element 6 thus extends in the axial direction, and not in the radial direction. Considering a second sealing element 6 comprising a ring 61 and an O-ring 63 as described previously, the ring 61 and the O-ring 63 are then superimposed in the axial direction.

[0084] The operation is identical to the operation already described with reference to Figures 2 to 5.

[0085] [Fig.7] also schematically shows a conduit 50f connecting the housing 4 to the internal volume 2 of the rotating machine 1. In the example illustrated, the conduit 50f is formed in the first assembly 10.

[0086] As a variant, two through conduits 50 are formed, one to ensure the injection of oil as already described, and the other to allow an outlet of the air present in the housing 4. These two conduits 50 can be formed according to the different embodiments described, either in combination, or by doubling one of the embodiments.

[0087] An example of a method for assembling such a rotating machine is now described.

[0088] As indicated previously, a problem lies in carrying out initial lubrication of the housing 4 in order to ensure lubrication during the first commissioning.

[0089] The conduit 50 makes it possible to ensure such initial lubrication.

[0090] We therefore propose a method taking this constraint into account.

[0091] A first set 10 and a second set 20 are firstly provided.

[0092] A rolling bearing 30 is positioned so that the first assembly 10 and the second set 20 are movable in rotation relative to each other.

[0093] This rolling bearing 30 is positioned in an internal volume between the first assembly 10 and the second assembly 20.

[0094] A first dynamic sealing element 40 is provided at an interface between the first assembly 10 and the second assembly 20 comprising a housing 4. The first dynamic sealing element 40 ensures the sealing of the internal volume 2 with respect to the external environment,

[0095] A second dynamic sealing element 6 is then provided positioned at an interface between the first assembly 10 and the second assembly 20, between the internal volume 2 and the housing 4, said second sealing element 6 being adapted for allow oil to pass from the internal volume 2 to the housing 4 when the pressure difference between the internal volume 2 and the housing 4 is less than a pressure threshold value so as to allow lubrication of the first sealing element 40 by the fluid coming from the internal volume, and to prevent oil from passing from the internal volume 2 to the housing 4 when the pressure difference between the internal volume 2 and the housing 4 exceeds the threshold value is greater than said pressure threshold value, The second dynamic sealing element 6 is thus interposed between the housing 4 comprising the dynamic sealing element 40 and the internal volume 2 comprising the rolling bearing 30.

[0096] Depending on the structure of the first assembly 10 and the second assembly 20, the first dynamic sealing element 40 and the second dynamic sealing element 6 may be positioned before or after the rolling bearing 30.

[0097] Oil is then injected into the housing 4 via the conduit 50, in particular in the case where the conduit 50 opens into the internal volume 2. In the case where a second through conduit 50 is present, a volume of air present in the housing 4 then escapes from the housing 4 via this second through conduit 50 which is then open.

[0098] The conduit 50 is then closed by means of a plug 52, typically via the end of the conduit 50 opposite its end opening into the housing 4, and where appropriate the second through conduit.

[0099] The various components 3 defining the rotating machine 1 are then assembled in the internal volume 2.

[0100] In the case where the conduit 50 opens not into the internal volume 2 but towards the outside, the steps of injecting oil and closing the conduit (or where appropriate the conduits) can be carried out following the assembly of the different components 3 defining the rotating machine 1 in the internal volume 2.

[0101] It is understood that in the case where the conduit 50 (or where appropriate the conduits) opens into the internal volume 2, the assembly of the different components 3 forming the rotating machine 1 will make access to the conduit 50 difficult or even impossible. In such a case, the injection of oil into the housing 4 and the sealing of the conduit 50 are therefore carried out beforehand.

[0102] Conversely, if the conduit (or where appropriate the conduits) opens to the outside, the steps of injecting oil and closing the conduit can be carried out following assembly as long as the conduit 50 remains accessible.

[0103] This method is particularly suitable for the initial assembly of a rotating machine, and also for reassembly operations following a maintenance operation. More generally, this method is suitable for any assembly operation of a rotating machine which requires initial lubrication of the housing 4.

[0104] The structure as proposed thus makes it possible to protect the seals of the machines. rotating machines providing insulation of an internal volume from the ambient environment against pressure rises within the internal volume, but also against lack of lubrication in the housing, and against pressure rises in the housing due to heating. The housing can thus be reduced because it no longer has to fulfill an oil storage and reserve function since the lubrication of the first sealing element 40 is ensured with oil coming from the internal volume of the rotating machine. The rotating machine is more reliable, less bulky, and no longer requires specific maintenance of the housing oil.

[0105] Although the present invention has been described with reference to specific exemplary embodiments, it is obvious that modifications and changes may be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various illustrated / mentioned embodiments may be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

[0106] It is also obvious that all the characteristics described with reference to a method are transposable, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device are transposable, alone or in combination, to a method.

Claims

Claims

1. Rotating machine (1) comprising a first assembly (10) and a second assembly (20) movable in rotation relative to each other along an axis of rotation (XX), said rotating machine (1) comprising a casing defining an internal volume (2), in which an interface between the first assembly (10) and the second assembly (20) comprises a housing (4) provided with a first dynamic sealing element (40) ensuring the sealing of the internal volume (2) with respect to the external environment, in which a second dynamic sealing element (6) is positioned at an interface between the first assembly (10) and the second assembly (20), between the internal volume (2) and the housing (4),said second sealing element (6) being adapted to allow a passage of oil from the internal volume (2) to the housing (4) when the pressure difference between the internal volume (2) and the housing (4) is less than a pressure threshold value so as to allow lubrication of the first sealing element (40) by the fluid coming from the internal volume, and not to allow a passage of oil from the internal volume (2) to the housing (4) when the pressure difference between the internal volume (2) and the housing (4) exceeds the threshold value is greater than said pressure threshold value, characterized in that a through conduit (50) is formed in the first assembly (10) or in the second assembly (20) so as to connect the housing (4) to the internal volume (2) or to the external environment, said through conduit (50) being closed by a plug (52).,

2. A rotating machine (1) according to claim 1, wherein the through conduit (50) is formed in a casing of the rotating machine or in a shaft of the rotating machine (1).

3. Rotating machine (1) according to one of claims 1 or 2, comprising a second through conduit (50) formed in the first assembly (10) or in the second assembly (20) so as to connect the housing (4) to the internal volume (2) or to the external medium, said through conduit (50) being closed by a plug (52).

4. Rotating machine (1) according to one of claims 1 to 3, in which the second sealing element (6) comprises a passage adapted to close when the pressure difference between the internal volume (2) and the housing (4) exceeds the threshold value.

5. Rotating machine according to one of claims 1 to 4 characterized in that the second sealing element (6) is adapted to, when the pressure difference between the internal volume (2) and the housing (4) is less than or equal to the pressure threshold value, allow oil to pass from the housing (4) to the internal volume (2), and when the pressure difference between the internal volume (2) and the housing (4) is greater than the pressure threshold value, isolate the housing (4) from the internal volume (2).

6. Rotating machine (1) according to one of the preceding claims, comprising a cylinder block provided with a plurality of housings extending radially relative to the axis of rotation (XX) in which cylinders are arranged, and a multi-lobe cam surrounding the cylinder block.

7. A method of assembling a rotating machine according to claim 1, wherein: - a first assembly (10) and a second assembly (20) are provided - a rolling bearing (30) is provided positioned in an internal volume (2) between the first assembly (10) and the second assembly (20), so that the first assembly (10) and the second assembly (20) are movable in rotation relative to each other along an axis of rotation (XX), - a first dynamic sealing element (40) is provided at an interface between the first assembly (10) and the second assembly (20) comprising a housing (4), said first dynamic sealing element (40) ensuring the sealing of the internal volume (2) with respect to the external environment, - a second dynamic sealing element (6) is provided positioned at an interface between the first assembly (10) and the second assembly (20), between the internal volume (2) and the housing (4),said second sealing element (6) being adapted to allow a passage of oil from the internal volume (2) to the housing (4) when the pressure difference between the internal volume (2) and the housing (4) is less than a pressure threshold value so as to allow lubrication of the first sealing element (40) by the fluid coming from the internal volume, and to not allow a passage of oil from the internal volume (2) to the housing (4) when the pressure difference between the internal volume (2) and the housing (4) exceeds the threshold value is greater than said pressure threshold value, - a volume of oil is injected into the housing (4) via a conduit (50) formed in the first assembly (10) or in the second assembly (20) and opening into the housing (4), - the conduit (50) is closed by means of a plug (52), - components (3) are provided and assembled so as to form a rotating machine between the first assembly (10) and the second assembly (20), said rotating machine (1) being a rotating machine, in which one of the first assembly (10) and the second assembly (20) comprises a casing, and the other of the first assembly (10) and the second assembly (20) comprises a shaft.

8. Method according to claim 7, in which the conduit (50) connects the housing (4) to the internal volume (2), and in which the injection of the volume of oil into the housing (2) and the sealing of the conduit (50) are carried out prior to the assembly of the components (3) forming the rotating machine.

9. Method according to claim 7, in which the conduit (50) connects the housing (4) to an external volume, and in which the injection of the volume of oil into the housing (2) and the sealing of the conduit (50) are carried out following the assembly of the components (3) forming the rotating machine.

10. A method according to claim 7, wherein the first assembly (10) or the second assembly (20) comprises a second conduit (50) allowing air to escape from the housing (4) when injecting a volume of oil into the housing (4) via the conduit (50), and wherein said second conduit (50) is closed by means of a plug following the step of injecting a volume of oil into the housing (4) via the conduit (50).

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