MECHANICAL SYSTEM PROVIDED WITH A SUMP RECEIVING, ABOVE COMPONENTS TO BE LUBRICATED OR COOLED, A TANK OF A LUBRICATING FLUID SYSTEM

Abstract

A mechanical system comprising a sump and at least one component to be lubricated or cooled arranged in the sump, the mechanical system comprising a lubricating fluid system provided with a lubricating fluid and a tank arranged in the sump. The tank is a leaking tank and is situated above said at least one component to be lubricated or cooled, the lubricating fluid flowing out of the tank by force of gravity, so as to reach said at least one component to be lubricated or cooled. The lubricating fluid system has at least one lift flow generator connected by at least one filling line to the tank and to at least one suction point present in a bottom of the sump. The lift flow generator fills the tank with the lubricating fluid present in said bottom at least during a starting phase.

Claims

1. A mechanical system comprising a sump and at least one component to be lubricated or cooled arranged in the sump, the mechanical system comprising a lubricating fluid system provided with a lubricating fluid and a tank arranged in the sump, the tank being a leaking tank and being situated above the at least one component to be lubricated or cooled, the lubricating fluid flowing out of the tank by force of gravity so as to reach the at least one component to be lubricated or cooled, the lubricating fluid system comprising at least one lift flow generator connected by at least one filling line to the tank and to at least one suction point present in a bottom of the sump, the lift flow generator being configured to fill the tank with the lubricating fluid present in the bottom at least during a starting phase (P1), wherein the lubricating fluid system comprises at least one fluid circuit provided with a distribution pump connected to the tank by a hydraulic inlet connection, the fluid circuit having a hydraulic outlet network comprising at least one distribution circuit configured to eject the lubricating fluid to the at least one component to be lubricated or cooled, the distribution pump being connected to the hydraulic outlet network and configured to draw the lubricating fluid from the tank and make this lubricating fluid flow from the hydraulic inlet connection to the hydraulic outlet network.

2. The mechanical system according to claim 1, wherein the tank is a leaking tank having a leakage flow rate less than a supply flow rate of lubricating fluid in the filling line.

3. The mechanical system according to claim 1, wherein the mechanical system is configured to be able to move within a predetermined movement space in relation to a reference frame of this mechanical system, the sump comprising, at the end of the starting phase (P1), a volume of lubricating fluid less than a predetermined volume allowing the at least one component to be lubricated or cooled to be at least partially submerged when the mechanical system moves in the predetermined movement space.

4. The mechanical system according to claim 1, wherein the tank comprises a leaking enclosure and at least one collector tank arranged in the enclosure, the collector tank being configured to overflow into the enclosure and be filled with lubricating fluid by the enclosure at the end of the starting phase (P1), the hydraulic inlet connection running from the collector tank to the distribution pump.

5. The mechanical system according to claim 1, wherein the hydraulic outlet network comprises, upstream of the at least one distribution circuit, one or more of the following members: a cooler, a heater, a filter, a pressure relief connection opening into the sump, a pressure sensor, a particle counter.

6. The mechanical system according to claim 1, wherein the at least one lift flow generator comprises at least one electromechanical priming pump connected to at least one suction point and to the tank.

7. The mechanical system according to claim 1, wherein the at least one lift flow generator comprises an ejector having an outlet hydraulically connected to the tank, the ejector having a first inlet hydraulically connected to the at least one suction point, the ejector having a second inlet hydraulically connected to the hydraulic outlet network.

8. The mechanical system according to claim 7, wherein the hydraulic outlet network comprises a narrowed section between the ejector and the distribution pump.

9. The mechanical system according to claim 1, wherein the lubricating fluid system comprises at least two fluid circuits opening onto at least one distribution circuit, each fluid circuit being provided with its own distribution pump connected to the tank by its own hydraulic inlet connection and its own hydraulic outlet network.

10. The mechanical system according to claim 9, wherein the two fluid circuits comprise a main circuit and a back-up circuit that can be used in the event of failure of the main circuit.

11. The mechanical system according to claim 1, wherein the at least one lift flow generator comprises an ejector having an outlet hydraulically connected to the tank, the ejector having a first inlet hydraulically connected to at least one suction point, the ejector having a second inlet hydraulically connected to an injection pump, the injection pump being hydraulically connected to the tank.

12. The mechanical system according to claim 1, wherein the at least one lift flow generator comprises several lift flow generators.

13. An aircraft provided with a gearbox setting a rotor in motion, wherein the gearbox is the mechanical system according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The disclosure and its advantages appear in greater detail in the context of the following description of embodiments given by way of illustration and with reference to the accompanying figures, in which:

[0074] FIG. 1 is a diagram showing a mechanical system according to the disclosure during a starting phase;

[0075] FIG. 2 is a diagram showing the mechanical system of FIG. 1 during a nominal operating phase;

[0076] FIG. 3 is a diagram showing a mechanical system according to the disclosure during a starting phase;

[0077] FIG. 4 is a diagram showing a mechanical system according to the disclosure during a starting phase;

[0078] FIG. 5 is a diagram showing the mechanical system of FIG. 4 during a nominal operating phase; and

[0079] FIG. 6 is a diagram showing the mechanical system provided with several lift flow generators.

DETAILED DESCRIPTION

[0080] Elements that are present in more than one of the figures are given the same references in each of them.

[0081] Three directions X, Y, and Z orthogonal to each other are shown in the figures. The first direction X is referred to as the longitudinal direction. The second direction Y is referred to as the transverse direction. Finally, the third direction Z is referred to as the direction in elevation.

[0082] FIGS. 1 to 5 show mechanical systems 100.

[0083] Regardless of the embodiment, and in reference to FIG. 1, for example, the mechanical system 100 comprises a sump 50. The sump 50, and for example a covering 151 of the sump 50 extends upwards from a bottom 51 to a top part 53, passing through an intermediate part 52.

[0084] Moreover, the mechanical system 100 is provided with at least one component 90 to be lubricated or cooled accommodated in the intermediate part 52 of the sump 50. Therefore, the mechanical system 100 may comprise a plurality of components 91, 92 to be lubricated or cooled. The component or components 90 may be in motion when the mechanical system 100 is operating. According to examples, a component 90 may comprise moving components that may rotate, such as shafts and bearings, as well as power transmitting and speed reducing or increasing components, such as gear members.

[0085] Moreover, this mechanical system 100 may be able to move during use in relation to a reference frame X, Y, Z attached to this mechanical system 100, within a movement space 200. For example, the mechanical system 100 is able to rotate about two axes parallel to the axes X, Y within the confines of the movement space 200.

[0086] The mechanical system 100 may possibly be a gearbox 155 of an aircraft 150 rotating at least one rotor 160. This mechanical system 100 may then function with predetermined nose-up and nose-down angles.

[0087] Moreover, the mechanical system 100 comprises a lubricating fluid system 80 provided with a lubricating fluid 85 for lubricating and/or cooling each component 90. For example, the lubricating fluid 85 comprises oil.

[0088] This lubricating fluid system 80 is thus provided with a tank 1 arranged in the sump 50. The tank 50 is arranged above the component or components 90, i.e., in the top part 53 of the sump 50. The term “above” is, for example, to be considered when the mechanical system 100 is stopped, or is arranged on a support resting on the ground in a predetermined position, possibly in an aircraft positioned on a landing area.

[0089] The tank 1 may comprise an enclosure 41 suitable for receiving some of the lubricating fluid 85 during operation. This enclosure 41 may be annular in shape, for example in order to be traversed by a shaft of the mechanical system 100. The enclosure may be attached to the sump. The tank 1 may further comprise at least one collector tank 2, 3 arranged in the enclosure 41, the collector tank 2, 3 being able to overflow into the enclosure 41 and be filled with lubricating fluid 85 by the enclosure 41. The collector tank is therefore an open container, open at the top, for example, arranged in the space delimited by the enclosure.

[0090] Moreover, the tank 1 is a leaking tank. To this end, the enclosure 41 may comprise at least one drainage hole 4, for example in a low point 400 of the enclosure 41. The lubricating fluid 85 then flows out of the tank 1 and in particular the enclosure 41 of its own accord, i.e., without the action of another member, by force of gravity, in order to reach the component or components 90 to be lubricated or cooled.

[0091] For example, the drainage hole or holes 4 are connected by one or more drainage lines 31 to one or more distribution circuits 30. Such a distribution circuit 30 may comprise a distribution manifold provided with at least one fluid sprayer, such as a simple hole, a nozzle or the like. The drainage hole or holes 4 are optionally connected by one or more drainage lines 31 to a dedicated distribution circuit 9, according to the possibility shown, or may be connected to at least one shared distribution circuit.

[0092] Indeed, in order to convey the lubricating fluid 85 from the tank 1 to the component or components 90 to be lubricated or cooled, the lubricating fluid system 80 may comprise at least one other fluid circuit.

[0093] The lubricating fluid system 80 may thus comprise at least one fluid circuit 71, 72 provided with a distribution pump 10, 22.

[0094] The distribution pump 10, 22 of a fluid circuit 71, 72 may for example be a mechanical pump set in motion by at least one component 90 of the mechanical system 100. Therefore, as long as the mechanical system 100 is not in operation, the mechanical pump 10, 22 is inactive. An electromechanical pump may also be envisaged.

[0095] The distribution pump 10, 22 of a fluid circuit 71, 72 is fluidly connected to the tank 1 by a hydraulic inlet connection 61, 63 of the fluid circuit 71, 72. A hydraulic inlet connection 61, 63 may comprise one or more pipes, a valve or the like.

[0096] Furthermore, the distribution pump 10, 22 of a fluid circuit 71, 72 is fluidly connected to a hydraulic outlet network 62, 64 of this fluid circuit 71, 72. Such a hydraulic outlet network 62, 64 comprises at least one distribution circuit 30 configured to transfer the lubricating fluid 85 to at least one component 90 to be lubricated or cooled. Therefore, the distribution pump 10, 22 is configured to draw the lubricating fluid 85 from the tank 1 and make this lubricating fluid 85 flow from the hydraulic inlet connection 61, 63 to the hydraulic outlet network 62, 64.

[0097] Two fluid circuits 71, 72 may have the same distribution circuit 30 or separate distribution circuits 17, 24 according to the examples shown. Reference number 30 is used to denote a distribution circuit in general, reference numbers 9, 17, 24 denoting specific distribution circuits.

[0098] According to another feature, when at least two fluid circuits 71, 72 are provided, each fluid circuit 71, 72 may have its own distribution pump 10, 22 connected to the tank 1 by its own hydraulic inlet connection 61, 63, and its own hydraulic outlet network 62, 64.

[0099] According to another feature, when at least two fluid circuits 71, 72 are provided, the two fluid circuits 71, 72 may form a main circuit 71 and a back-up circuit 72 that can be used in the event of failure of the main circuit 71.

[0100] According to another feature, the distribution pump 10, 22 of a fluid circuit 71, 72 may, depending on the embodiment, be connected to the enclosure 41 of the tank 1 according to the example in FIGS. 4 and 5.

[0101] Alternatively, the distribution pump 10, 22 of a fluid circuit 71, 72 may be connected to a collector tank 2, 3 of the tank 1 according to the examples of FIGS. 1, 2 and 3. In this case, at least one collector tank 2, 3, or at least one collector tank 2, 3 per fluid circuit 71, 72, is arranged in the enclosure 41. The hydraulic inlet connection 61, 63 then extends from a collector tank 2, 3 to a distribution pump 10, 22.

[0102] If there is a main circuit 71 and a back-up circuit 72 cooperating with two respective collector tanks 2, 3, the collector tank 3 connected to the back-up circuit 72 may, for safety reasons, be closer to a low point of the tank 1 than the collector tank 2 connected to the main circuit 71. A leak occurring in an upper section of the enclosure 41 then does not have an impact on the collector tank 3 connected to the back-up circuit 72.

[0103] According to another feature, the hydraulic outlet network 62, 64 of a fluid circuit 71, 72 may comprise, upstream of the distribution circuit or circuits 17, 24 of this fluid circuit 71, 72, one or more of the following members: a cooler 12, a heater 13, a filter 14, a pressure relief connection 11, 20 opening into the sump 50, a pressure sensor 15, 23, a particle counter 99, 990. A filter 14 may comprise a filtering member 141 and a bypass connection 142, and a clogging detector. A pressure relief connection may comprise a pressure relief valve opening on the bottom of the sump, or at least a pipe. A particle counter may comprise a standard particle sensor used to count or capture particles circulating in the fluid and, for example, an optical or induction counter. A particle counter may optionally be arranged upstream of a filter.

[0104] According to the examples shown, a main fluid circuit 71 comprises a cooler 12, a heater 13, a filter 14, a pressure relief connection 11 opening into the sump 50, a pressure sensor 15. For example, the hydraulic outlet network 62 of the main fluid circuit 71 comprises a first hydraulic connection leaving the distribution pump 10. This first hydraulic connection opens, at a junction, on the pressure relief connection 11 and a second hydraulic connection that leaves the sump to reach the cooler 12 and the heater 13. A third hydraulic connection connects the cooler 12 and the heater 13 to a filter 14, the third connection being able to comprise an optional particle counter 99. This filter 14 opens via a connection returning into the sump on a distribution circuit 17 equipped with a pressure sensor 15. Furthermore, a back-up fluid circuit 72 comprises a pressure relief connection 20 opening into the sump 50 and a pressure sensor 23. A valve may be arranged in the sump upstream of the heater and the cooler.

[0105] For example, the hydraulic outlet network 64 of the back-up fluid circuit 72 comprises a first hydraulic connection leaving the distribution pump 22. This first hydraulic connection opens, at a junction, on the pressure relief connection 20 and a second hydraulic connection that reaches a distribution circuit 24 equipped with a pressure sensor 23. The second hydraulic connection may comprise a particle counter 990. The back-up fluid circuit 72 is not provided with a filter, a heater and a cooler in order to limit the risk of leaks.

[0106] According to another aspect, the tank 1 may house at least one lubricating fluid level sensor 7, 8 and at least one temperature sensor 5, 6.

[0107] The term “sensor” denotes a physical sensing device capable of directly measuring the parameter in question but also a system that may comprise one or more physical sensing devices as well as means for processing the signal that make it possible to provide an estimation of the parameter from the measurements provided by these physical sensing devices.

[0108] The various sensors 5, 6, 7, 8, 15, 23 cited above may communicate with a controller 95.

[0109] By way of example, the controller 95 may comprise at least one processor and at least one memory, at least one integrated circuit, at least one programmable system, or at least one logic circuit, these examples not limiting the scope to be given to the term “controller”. The term “processor” may refer equally to a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a microcontroller, etc.

[0110] The controller 95 may in particular be configured to generate an alert signal transmitted to an alerter 96 capable of generating at least one alert. Each alert may be in the form of a visual alarm, for example emitting a light with a light-emitting diode or an equivalent or one or more characters being displayed on a screen, an audible alarm, via a loudspeaker, and/or a haptic alarm, for example by means of a vibrating unit causing a member held or worn by an individual to vibrate. For example, an alert may be generated when a pressure sensor 15, 23 delivers a signal carrying a pressure lower than a threshold, when a temperature sensor 5, 6 measures a temperature higher than a threshold, when a lubricating fluid level sensor 7, 8 measures a level lower than a threshold.

[0111] Irrespective of the preceding examples and in reference to FIG. 1, the lubricating fluid system 80 comprises at least one lift flow generator 35. The lift flow generator 35 is connected by at least one filling line 39 to the tank 1 and to at least one suction point 36 present in the bottom 51 of the sump 50.

[0112] The lift flow generator 35 is configured to fill the tank 1 with the lubricating fluid 85 present in the bottom 51 at least during a starting phase P1. The tank 1 may be a leaking tank, having a leakage flow rate less than a supply flow rate of lubricating fluid 85 in the filling line 39.

[0113] A lift flow generator 35 may optionally comprise an ejector 18, 19 connected by a respective filling line 39 to the tank 1 and to at least one suction point 36, optionally via a supply line 25, 26.

[0114] According to the first embodiment of FIGS. 1 and 2, this ejector 18, 19 is also supplied with lubricating fluid by the hydraulic outlet network 62, 64 of a fluid circuit. An ejector 18, 19 therefore has an outlet hydraulically connected to the tank 1 or to a collector tank 2, 3 by a filling line 39. This ejector 18, 19 also has a first inlet hydraulically connected to a supply line 25, 26 and a second inlet hydraulically connected to the hydraulic outlet network 62, 64.

[0115] The hydraulic outlet network 62, 64 optionally comprises a narrowed section 16, 21 between the ejector 18, 19 and the distribution pump 10, 22.

[0116] According to the second embodiment of FIG. 3, this ejector 18, 19 is independent, being supplied by a dedicated injection pump 381, 382, the injection pump 381, 382 being connected to a collector tank 2, 3. The injection pump 381, 382 may be a mechanical pump possibly set in motion by the mechanical system 100, or an electromechanical pump.

[0117] FIG. 6 shows a mechanical system provided with several lift flow generators. If applicable, several lift flow generators may be in the form of ejectors optionally communicating with the same pump. If applicable, several lift flow generators may lead to different suction points. According to the example shown, the main circuit 71 comprises several lift flow generators 18 of the ejector type, each hydraulically connected to the tank 1 or to the same collector tank 2 by a filling line 39, to a supply line and to the same hydraulic outlet network 62. Similarly, the back-up circuit 72 comprises several lift flow generators of the ejector type, each hydraulically connected to the tank 1 or to the same collector tank 3 by a filling line 39, to a supply line and to the same hydraulic outlet network 64.

[0118] Irrespective of the number of lift flow generators, the first embodiment and the second embodiment operate identically. Regardless of how an ejector 18, 19 of a lift flow generator 35 is supplied with lubricating fluid, and in reference to FIG. 1, the enclosure 41 is empty when at rest. Each collector tank 2, 3 contains a portion of the lubricating fluid 85. Another portion of the lubricating fluid is stored in the bottom 51 of the sump 50 of the mechanical system 100.

[0119] During a starting phase P1, the lubricating fluid system 80 implements a step of emptying STP1 the bottom 51 by transferring the lubricating fluid 85 that is in this bottom 51 at rest to the tank 1.

[0120] The mechanical system 100 is set in motion by a drive unit that is not shown and is not part of the subject matter of the disclosure. As a result, each distribution pump 10, 22 or injection pump 381, 382, depending on the embodiment, is set in motion. Each distribution pump 10, 22 then draws up the lubricating fluid contained in the respective collector tank 2, 3. Each distribution pump 10, 22 or injection pump 381, 382, depending on the embodiment, then conveys the fluid drawn from the tank 1 to a distribution circuit 17, 24 and at least one ejector 18, 19 forming a lift flow generator 35. Therefore, this ejector 18, 19 draws up the lubricating fluid contained in the bottom 51 and conveys it into the tank 1.

[0121] In reference to FIG. 2, during an operating phase P2, the lubricating fluid system 80 implements a step of lubricating STP2 the component or components 90 to be lubricated or cooled with the lubricating fluid 85 contained in the tank 1. Indeed, the lubricating fluid 85 leaves the tank 1 and lubricates the component or components 90. Moreover, each distribution pump 10, 22 draws the lubricating fluid 85 from the tank 1 and transfers it to at least one distribution circuit 17, 24.

[0122] Moreover, the lubricating fluid 85 conveyed to the component or components 90 falls by force of gravity into the bottom 51 of the sump 50. Each ejector 18, 19 makes it possible to carry out a step of transferring STP3 the lubricating fluid 85 falling by force of gravity into the bottom 51 to the tank 1.

[0123] If a fluid circuit 71, 72 fails, the component or components 90 are lubricated at least by the tank 1 for a minimum time period.

[0124] Moreover, the sump 50 comprises, at the end of the starting phase P1, a volume 201 of lubricating fluid 85 less than a predetermined volume allowing the lubricating fluid 85 to splash at least one component 90 to be lubricated or cooled, within the limits of the permitted movement of the mechanical system 100.

[0125] According to the embodiments of FIGS. 4 to 5, a lift flow generator 35 may comprise at least one electromechanical priming pump 37 connected to at least one suction point 36 and to the enclosure 41 of the tank 1. The tank 1 may then not be provided with a collector tank. Furthermore, at least one fluid circuit 71, 72 may comprise a lift flow generator 35 of the ejector 18 type. This ejector 18 has an outlet hydraulically connected to the tank 1, a first inlet hydraulically connected to at least one suction point 36 optionally via a supply line 25, and a second inlet hydraulically connected to a distribution pump 10, 22 according to the example shown or a dedicated injection pump 381, 382 connected to the enclosure 41 of the tank 1.

[0126] The enclosure 41 is empty or almost empty when at rest.

[0127] During the starting phase P1 shown in FIG. 4, the lubricating fluid system 80 implements the step of emptying STP1 the bottom 51 by transferring the lubricating fluid 85 that is in this bottom 51 at rest to the enclosure 41. Each electromechanical priming pump 37 is set in motion, for example on the order of the controller 95, to draw the lubricating fluid 85 from the bottom 51 of the sump 50 and inject it into the tank 1.

[0128] The mechanical system 100 may remain stationary.

[0129] In reference to FIG. 5, during an operating phase P2, the mechanical system 100 is set in motion. The lubricating fluid system 80 implements a step of lubricating STP2 the component or components 90 to be lubricated or cooled with the lubricating fluid 85 contained in the tank 1. Indeed, the lubricating fluid 85 leaves the tank 1 and lubricates the component or components 90. Moreover, each distribution pump 10, 22 draws the lubricating fluid 85 from the tank 1 and transfers it to at least one distribution circuit 17, 24.

[0130] Moreover, the lubricating fluid 85 conveyed to the component or components 90 falls by force of gravity into the bottom 51 of the sump 50. Each ejector 18, 19 makes it possible to carry out a step of transferring STP3 the lubricating fluid 85 that has fallen by force of gravity into the bottom 51 to the tank 1.

[0131] If a fluid circuit 71, 72 fails, the component or components 90 are lubricated at least by the lubricating fluid 85 contained in the tank 1 for a minimum time period.

[0132] Moreover, the sump 50 comprises, at the end of the starting phase P1, a volume 201 of lubricating fluid 85 less than a predetermined volume allowing the lubricating fluid 85 to splash at least one component 90 to be lubricated or cooled, within the limits of the permitted movement of the mechanical system 100.

[0133] Naturally, the present disclosure is subject to numerous variations as regards its implementation. Although several embodiments are described above, it should readily be understood that it is not conceivable to identify exhaustively all the possible embodiments. It is naturally possible to envisage replacing any of the means described by equivalent means without going beyond the ambit of the present disclosure.

[0134] For example, a priming pump may equip the embodiments of FIGS. 1 to 3. According to another example, the embodiments of FIGS. 3 to 6 may comprise several lift flow generators, as in the teaching of FIG. 6.