Mechanical system equipped with moving mechanical elements, a magnetic stopper and a lubrication system equipped with mechanical and magnetic filters.

Abstract

The present invention relates to a mechanical system (1) comprising movable mechanical elements (6) to be lubricated or cooled in a housing, the mechanical system (1) having a lubrication system (10) equipped with a reservoir (7) containing a lubricating fluid (4), the lubrication system (10) having a main fluid circuit (101) extending from the reservoir (7) to a fluid spray circuit (12), the main fluid circuit (101) having a flow generator (11), a mechanical filter (25), and a magnetic plug (80). The main fluid circuit (101) includes a magnetic filter (30) through which the lubricating fluid (4) flows between the reservoir (7) and the fluid spray circuit (12), the magnetic filter (30) comprising at least one magnetized wall (32). Abstract figure: Figure 1

Description

Title of the invention: Mechanical system equipped with movable mechanical elements, a magnetic stopper and a lubrication system equipped with mechanical and magnetic filters.

[0001] The present invention relates to a mechanical system equipped with movable mechanical elements, a magnetic stopper and a lubrication system equipped with mechanical and magnetic filters.

[0002] A mechanical system may include moving mechanical elements to be cooled or lubricated, such as shafts, bearings, mechanical elements for power transmission or even for reducing or increasing rotational speed, sprockets, wheels, splines, etc.

[0003] For example, a rotary-wing aircraft may include a rotor that contributes at least partially to the aircraft's lift. To rotate such a rotor, a mechanical system of the "power transmission" type may mechanically connect one or more engines to the rotor. Such a power transmission includes mechanical components that require lubrication or cooling.

[0004] Such a mechanical system then includes a lubrication system for delivering a lubricating fluid to mechanical elements to lubricate and / or cool them. Such mechanical elements are hereinafter referred to as "mechanical elements to be lubricated or cooled".

[0005] A known lubrication system includes a main fluid circuit. This main fluid circuit contains a lubricating fluid in a reservoir. The reservoir is, for example, formed by the bottom of a housing of the mechanical system to be lubricated or cooled. Furthermore, the fluid circuit is equipped with a pump that draws the fluid from the reservoir. The pump then moves the fluid to at least one fluid spray circuit, sometimes called a "lubrication ramp" or "fluid spray ramp." The fluid is then expelled from the fluid spray circuit to reach the mechanical components to be lubricated or cooled before returning by gravity to the bottom of the housing. In addition, the main fluid circuit includes a cooler. The term "cooler" refers to a device capable of lowering the temperature of a fluid, unlike a heater.

[0006] Furthermore, the lubricating fluid can be contaminated by metallic and magnetic pollutants. Therefore, the mechanical system may include mechanical filtration means to prevent large pollutants, for example on the order of 10 microns and larger, from obstructing, in particular, the fluid spray circuit and to ensure the reliability of the mechanical contacts.

[0007] Thus, strainers can be arranged upstream of the pump and / or the fluid spray circuit. The main fluid circuit can also include a cartridge filter located upstream of the fluid spray circuit. Such a cartridge filter comprises a tank housing a porous filter cartridge. The fluid enters the tank, passes through the casing, and then exits the filter. Consequently, particles larger than the openings in the casing are trapped in the tank.

[0008] Optionally, the lubrication system may consist solely of the main fluid circuit, or it may also include a backup fluid circuit. In this case, both the main and backup fluid circuits may be configured to draw lubricating fluid from the same reservoir and to deliver this fluid to the same fluid spray circuit or to separate fluid spray circuits. The backup fluid circuit is designed to allow the mechanical system to operate for at least a predetermined period in the event of a failure of the main fluid circuit. The backup fluid circuit may extend only within the mechanical system housing to prevent leakage outside the mechanical system.

[0009] Furthermore, during its operation, the mechanical system can generate metallic and magnetic particles as a result of the degradation of at least one of its rotating mechanical elements, for example, by chipping of the teeth of a pinion or gear. These metallic and magnetic particles, indicative of a malfunction, are of significant size, on the order of a tenth of a millimeter.

[0010] To detect abnormal operation of the mechanical system, the system typically includes a removable magnetic plug that isolates, immobilizes, and removes metallic and magnetic particles resulting from the abnormal operation that fall into the reservoir. The magnetic plug can be connected to an alarm to generate an alert when a certain quantity of captured metal is detected. A magnetic plug is usually located at the bottom of the reservoir and captures metallic and magnetic particles falling to the bottom. The fluid circuit(s) can draw the lubricating fluid from the reservoir via a strainer to avoid drawing in these metallic and magnetic particles.

[0011] Furthermore, the lubricating fluid may be contaminated by a very fine metallic and magnetic powder. The metallic and magnetic powder comprises metallic and magnetic particles, on the order of approximately 0.5 to 3 microns and / or smaller than the perforations of the aforementioned strainer, suspended in the lubricating fluid. This metallic and magnetic powder may result from the manufacturing and / or assembly of the mechanical system, by shrink fitting and / or clamping, for example, or from the normal friction of the contact areas between its various moving mechanical elements. The metallic and magnetic powder does not affect the operation of the mechanical system or its lubrication system due on the one hand to its expected presence resulting from normal operation, and on the other hand to the very small dimensions of the particles constituting it.

[0012] The term "metallic particle" hereafter refers to large metallic and magnetic pollutants resulting from a malfunction or contamination during manufacturing or assembly, and covers, for example, any metallic and magnetic particle with a size difference greater than 10 microns between two distinct points on that particle. Conversely, the term "metallic powder" refers to any metallic and magnetic pollutant resulting from manufacturing, assembly, or normal and expected wear of the mechanical system (e.g., break-in, fretting), and covers, for example, any pollutant with a size difference of 10 microns or less between two distinct peripheral points. Furthermore, it is also possible to generate "metallic powder" with or without "metallic particles" during a malfunction.

[0013] In the presence of metallic powder, the mechanical system can continue to be used until its next maintenance, whereas in the presence of a certain quantity of metallic particles, premature maintenance action is undertaken.

[0014] However, some regulations require the detection of a small volume of metallic particles in a short period of time. To comply with this regulation, a magnetic stopper with a high magnetic attraction capacity can be used.

[0015] While effective at capturing large metal particles that fall into the reservoir, such a magnetic plug also attracts metal powder suspended in the lubricating fluid within the reservoir. Therefore, the magnetic plug is likely to quickly capture a large quantity of material, even in the presence of normal wear, via the metal powder. The circulation of the fluid in the lubrication system tends to circulate the metal powder, which gradually adheres to the magnetic plug. Consequently, a magnetic plug with a strong attraction capacity can generate false alarms, leading to unnecessary and costly maintenance. Such a magnetic plug has the advantage of detecting potential flaking and generating an alert accordingly, but the disadvantage of potentially generating false alarms in the medium term due to the capture of metal powder passing nearby.The presence of metallic powder resulting from normal operation can further delay the capture of metallic particles resulting from a malfunction.

[0016] Document FR 3 083 283 B1 describes a mechanical system having, in particular, a magnetic stopper in a reservoir, as well as a magnet in a lubrication system. This magnetic stopper and the magnet form sensing devices. designed to capture passing metallic particles. The metals attracted by the magnet are swept away by the lubricating fluid when the lubrication system is active. Therefore, this document specifies the installation of a bypass line.

[0017] Document FR 3 100 614 B1 describes a mechanical system having in particular magnetic stoppers in a reservoir and a particle counter.

[0018] The present invention then aims to provide a mechanical system equipped with a lubrication system designed to limit the number of false alarms generated with a magnetic stopper.

[0019] The present invention relates to a mechanical system comprising moving mechanical elements to be lubricated or cooled in a housing, the mechanical system having a lubrication system equipped with a reservoir containing a lubricating fluid, the lubrication system having a main fluid circuit extending from the reservoir to a fluid projection circuit, the main fluid circuit having a flow generator and a mechanical filter equipped with a cartridge having a porous envelope, the lubrication system comprising at least one magnetic plug.

[0020] The magnetic plug(s) are in contact with the lubricating fluid, at least during operation. Thus, a magnetic plug can be arranged, for example, in the reservoir or on a return path through which the lubricating fluid travels between a component to be lubricated or cooled and the reservoir. At least one magnetic plug can be outside the main fluid circuit.

[0021] For example, such a porous envelope of a mechanical filter may include a perforated wall, possibly folded accordion-style to present a maximized filtration surface.

[0022] In addition, the lubrication system may include at least one secondary fluid circuit. For example, a secondary fluid circuit may form a standard backup circuit partially or even entirely housed in the crankcase, and / or drawing the lubricating fluid from the same reservoir as the main fluid circuit.

[0023] Furthermore, the main fluidic circuit includes a magnetic filter through which the lubricating fluid passes between the reservoir and the fluid spray circuit, the magnetic filter comprising at least one magnetized wall.

[0024] Therefore, this mechanical system goes against preconceived notions by incorporating, in addition to a mechanical cartridge filter, a magnetic filter. Conversely, the magnetic cap is designed to capture metallic and magnetic contaminants present in the lubricating fluid after spraying the components to be lubricated or cooled, in order to detect any malfunction. Filtering metallic contaminants from the lubricating fluid thus appears, at first glance, to be counterproductive.

[0025] However, false alarms have been innovatively identified as resulting from the presence of a powerful magnetic plug. This magnetic plug effectively captures metallic and magnetic contaminants present in the tank, including, over time, very fine metal powder resulting from manufacturing and normal operation. The metal powder captured by the magnetic plug can thus generate a false alarm.

[0026] The invention also includes a magnetic stopper with a strong attraction capacity. In the absence of a malfunction, the lubricating fluid circulates within the mechanical system and thus passes through the magnetic filter. Metallic contaminants are attracted to the magnetized wall of this magnetic filter.

[0027] At this stage, the pollutants result solely from the normal operation of the mechanical system. Consequently, the amount of metallic powder likely to be attracted to the magnetic stopper is effectively reduced, and the risk of generating a false alarm is minimized. The mechanical filter, for its part, can filter other types of pollutants, while being less congested by metallic pollutants compared to a conventional system. The lubricating fluid is thus effectively decontaminated.

[0028] In the event of a malfunction such as flaking of a component of the mechanical system, large metallic particles fall towards the reservoir, by gravity for example, and are captured by the magnetic plug. This magnetic plug is therefore always placed upstream of the mechanical filter and the magnetic filter with respect to the direction of flow of the lubricating fluid from the reservoir to the fluid spray circuit in order to limit the risk of losing metallic particles to these filters.

[0029] Consequently, this mechanical system combines a magnetic filter with a mechanical filter within the main fluid circuit to at least limit the number of false alarms emitted by the magnetic plug. This results in potentially reduced capital and operating costs for the mechanical system.

[0030] The mechanical system may also include one or more of the following characteristics, taken alone or in combination.

[0031] According to one possibility, the main fluidic circuit may include a filtration strainer upstream of the magnetic filter, or even of the flow generator.

[0032] The terms "upstream" and "downstream" are to be considered with regard to the direction of fluid flow.

[0033] For example, the filter strainer is arranged in the tank, or even at an inlet of the main fluidic circuit.

[0034] According to a possibility compatible with the previous ones, the magnetic cap can be connected to an alerter.

[0035] The magnetic cap can generate a signal transmitted to the alarm. For example, the magnetic cap can then close an electrical circuit, electrically powering an alarm.

[0036] According to a possibility compatible with the preceding ones, the magnetic filter may include a retarder reducing a speed of movement of the lubricating fluid within the magnetic filter compared to a speed of movement reached at the inlet of the magnetic filter.

[0037] The main fluid circuit tends to move the lubricating fluid at a high flow rate (for example, greater than 800 l / h), which may seem favorable for cleaning this lubricating fluid. However, at such a high flow rate, only metallic and magnetic contaminants passing close to the magnetic wall are likely to be attracted and fixed to this wall. The speed reducer slows the lubricating fluid in the magnetic filter to increase the likelihood that metallic contaminants will be attracted to the magnetic wall.

[0038] According to a possibility compatible with the preceding ones, the magnetic filter may comprise an external tank and a tube disposed at least partially in the external tank, an external volume being contained between the external tank and the tube, an internal volume being delimited by the tube and in communication with the external volume, the main fluidic circuit comprising an upstream hydraulic connection going from the tank to an inlet of the magnetic filter, said inlet being hydraulically connected to an inlet volume formed by the external volume or the internal volume, the main fluidic circuit comprising a downstream hydraulic connection hydraulically linking to the fluid projection circuit the internal volume or the external volume not forming the inlet volume, the magnetic wall comprising the external tank or the tube.

[0039] Optionally, said inlet has an inlet passage surface through which the lubricating fluid passes, and the external volume has an external passage surface having an area greater than an area of ​​the inlet passage surface to form the retarder mentioned above.

[0040] This solution also has the advantage of being able to increase the magnetic surface area and therefore promote the capture of metallic and magnetic pollutants.

[0041] According to a possibility compatible with the previous ones, the tube can be a cylinder with a circular base.

[0042] According to a possibility compatible with the preceding ones, the tube may include at least one open intermediate passage surface connecting the external volume and the internal volume.

[0043] According to a first alternative embodiment of the magnetic wall, the magnetic wall may comprise a wall made of aluminum alloy or plastic, the magnetic wall including a support fixed to this wall made of aluminium alloy or plastic and equipped with at least one permanent magnet.

[0044] For example, such a support takes the form of a sock, made of plastic or other material, engaged on the wall made of aluminum alloy or plastic, this sock carrying at least one magnet.

[0045] The aluminium alloy has the advantage of being permeable to magnetic waves, which can promote the attraction of metallic pollutants.

[0046] Alternatively, the wall can be made of plastic.

[0047] Using a support bearing one or more magnets around a substantially non-magnetic surface allows for the easy recovery of collected metallic and magnetic pollutants. When an operator removes the magnetized support, the metallic and magnetic pollutants are no longer attracted by a magnetic force and fall away, making them easily collectable. This arrangement allows for the temporary suppression of the magnetism acting on the metallic and magnetic pollutants.

[0048] According to a second alternative embodiment of the magnetic wall, the magnetic wall may comprise a metallic wall attached to at least one permanent magnet or includes a hollow magnetic bar.

[0049] This second alternative has the advantage of comprising a large magnetized surface and of presenting an interesting efficiency / mass ratio.

[0050] According to another aspect, the main fluidic circuit may include an upstream hydraulic link going from the reservoir to an inlet of the magnetic filter, the upstream hydraulic link may include said flow generator, the downstream hydraulic link including at least one of the following equipment: a heater, a cooler, the mechanical filter.

[0051] The flow generator can be located in or outside the mechanical system.

[0052] Therefore, the magnetic filter can be downstream of the flow generator. The magnetic filter can be upstream of a heater, a cooler, and / or the mechanical filter to limit the number of pollutants conveyed to these components and to provide additional particle collection for characterization and quantification in case of malfunction before they are lost in the mechanical filter and / or the cooler and / or the heater.

[0053] According to another aspect and in the presence of a magnetic filter having an external tank and a tube, regardless of the way of obtaining the magnetic wall and according to a first variant, the tube may include the magnetic wall.

[0054] The tube can be magnetized, instead of the external tank to optimize the mass of the system for example.

[0055] According to a second variant, the external tank may include the magnetic wall.

[0056] Optionally, the magnetic filter and the mechanical filter may form a single filter, said magnetic wall comprising the external tank, the tube comprising the porous envelope.

[0057] A single piece of equipment then acts as both a magnetic and a mechanical filter. Furthermore, by retrofitting the same porous casing to an existing system, the filter can generate the same pressure drop as before.

[0058] According to one possibility, it is possible to place at least one magnet or a magnetic sock on the external tank of an existing mechanical filter to obtain a magnetic wall.

[0059] According to another aspect, the magnetic filter can be arranged outside of said housing.

[0060] Such an arrangement allows the magnetic filter to be easily removed if necessary. The The contents of the magnetic filter can be collected and analyzed to perform a health diagnosis of the mechanical system.

[0061] According to another aspect, the mechanical system may be a power transmission box. In addition to a mechanical system, the invention relates to an aircraft comprising such a mechanical system.

[0062] For example, the mechanical system is a power transmission box connected by a mechanical chain to at least one rotating wing to set it in rotation.

[0063] In addition to a mechanical system, the invention relates to a method for reducing the number of false alarms within a mechanical system comprising moving mechanical elements to be lubricated or cooled in a housing. The mechanical system has a lubrication system equipped with a reservoir containing a lubricating fluid. The lubrication system has a main fluid circuit extending from the reservoir to a fluid spray circuit. The main fluid circuit has a flow generator and a mechanical filter equipped with a cartridge having a porous casing. The lubrication system includes at least one magnetic plug. The magnetic plug may be in contact with the lubricating fluid, at least during operation, possibly outside the main fluid circuit, for example, in the reservoir or on a return path followed by the lubricating fluid from an element to be lubricated or cooled back to the reservoir.

[0064] The process comprises the following steps:

[0065] - circulation of the lubricating fluid in the main fluid circuit, the fluid exiting via the fluid projection circuit and returning to the reservoir,

[0066] - decontamination of the lubricating fluid circulating in the main fluid circuit with a magnetic filter and mechanical filter, the magnetic filter comprising at least one magnetized wall and possibly a retarder reducing the speed of movement of the lubricating fluid,

[0067] - generation of an alert with the magnetic cap in the presence of metal detected by this magnetic stopper.

[0068] This minimum quantity may be established by testing or results from regulations to be complied with, for example, the regulation called "Certification Specification for large helicopters CS-29" in English.

[0069] The invention and its advantages will become apparent in more detail in the following description, with illustrative examples given by reference to the accompanying figures, which represent:

[0070] [Fig. 1], a diagram illustrating a mechanical system according to the invention and the associated method,

[0071] [Fig. 2], an example of a magnetic wall equipped with a metal tube and at least one magnet,

[0072] the [Fig.3], an example of a magnetic filter,

[0073] [Fig. 4], an example of a magnetic filter,

[0074] the [Fig.5], an example of a magnetic filter,

[0075] the [Fig.6], an example of a magnetic filter, and

[0076] the [Fig.7], a diagram illustrating a filtration unit comprising a mechanical filter and a magnetic filter.

[0077] Elements present in several separate figures are assigned one and the same reference.

[0078] Figure 1 shows a mechanical system 1 according to the invention. This mechanical system 1 can be arranged within various structures and, for example, within a vehicle and possibly within an aircraft 2, as illustrated. The mechanical system 1 can be a power transmission box 8.

[0079] For example, the mechanical system 1 is arranged within an aircraft 2 to rotate, in particular, a rotor 3, possibly via an output rotor mast. Such a rotor 3 may be a main rotor of a helicopter, a rotor involved in yaw control, a propeller, etc.

[0080] Regardless of the nature of the mechanical system 1 and its arrangement, this mechanical system 1 comprises movable mechanical elements 6 to be lubricated or cooled. These mechanical elements 6 to be lubricated or cooled may include movable, or even rotating, elements relative to a housing 5. Each mechanical element 6 to be lubricated or cooled may include, for example, a shaft, a ball bearing mechanism or other, a power transmission element, a speed reduction or increase element, a pinion, a wheel, a splined component, etc.

[0081] The mechanical elements 6 are arranged in an internal volume delimited by the housing 5. This housing 5 may comprise a plurality of sub-assemblies which delimit together an enclosure in which are arranged the mechanical element(s) 6 to be lubricated or cooled.

[0082] In addition, the mechanical system 1 includes a lubrication system 10. This lubrication system 10 has a reservoir 7 containing a lubricating fluid 4. For example, a sub-assembly forming a bottom of the crankcase 5 forms at least part of the reservoir 7. The lubricating fluid 4 can be a lubricating liquid, such as a liquid comprising oil, or any other liquid suitable for lubricating and / or cooling a mechanical element 6.

[0083] The lubrication system 10 comprises one or more magnetic plugs 80, such as a conventional magnetic plug. The magnetic plug 80 is in contact with the lubricating fluid 4 in the reservoir 7, as illustrated. Alternatively, the magnetic plug 80 may be located in a path traversed by the lubricating fluid, for example, between a mechanical element 6 to be lubricated or cooled and the reservoir 7. For example, the magnetic plug 80 is fixed to the bottom of the reservoir 7. The magnetic plug 80 may include a receiving portion in contact with the lubricating fluid 4, and at least one magnetic attraction means for capturing metallic and magnetic contaminants, and in particular metallic particles resulting from spalling of the mechanical elements 6. Such an attraction means may include a permanent magnet. For example, the magnetic plug may be of the type described in EP patent 3627032.

[0084] Typically, the magnetic cap 80 can be connected to an alerter 81. Such an alerter 81 can generate a visual alarm, for example by means of the emission of a light with a light-emitting diode or equivalent or the display on a screen of one or more characters, an audible alarm, by means of a loudspeaker, and / or a haptic alarm, for example by means of a vibrating unit causing an organ held or worn by an individual to vibrate.

[0085] To move the lubricating fluid 4 towards the mechanical elements 6, the lubrication system 10 includes a main fluid circuit 101, or even in addition at least one secondary fluid circuit 102 such as a backup circuit for example.

[0086] To direct the lubricating fluid 4 to the mechanical components 6 to be lubricated or cooled, the main fluid circuit 101 extends from the reservoir 7 to a fluid spray circuit 12. The fluid spray circuit 12 may include one or more pipes 13 leading to at least one means for spraying the lubricating fluid 14, referred to for convenience as a "sprayer." Such a sprayer may be, for example, a nozzle or equivalent, a simple orifice in a pipe, a system mixing the lubricating fluid with a gas, etc.

[0087] Generally speaking, the term "piping" used previously and subsequently can represent a single pipe or a plurality of pipes attached to each other.

[0088] More specifically, the main fluidic circuit 101 includes a flow generator 11 for drawing the lubricating fluid from the reservoir 7. The flow generator 11 may include a pump or an ejector in communication with a main suction inlet immersed under normal conditions in the lubricating fluid 4 present in the reservoir 7.

[0089] Downstream of the flow generator 11 and upstream of the fluid spray circuit 12, the main fluid circuit 101 includes a mechanical filter 25. This mechanical filter 25 is equipped with a filtration device having a cartridge 26 with a porous casing 28. The porous casing 28 can form a filter wall comprising small perforations, for example, on the order of 10 to 25 micrometers or even less. The cartridge 25 can be disposed in a housing 27. The lubricating fluid 4 to be filtered enters the filtration device and reaches the volume disposed between the housing 27 and the porous casing 28, passes through this porous casing 28, and then exits the filtration device filtered. Optionally, the mechanical filter 25 includes a bypass channel 29 to bypass the filtration device, for example, when this filtration device is obstructed.

[0090] Optionally, the main fluid circuit 101 may include a heater 20 and / or a cooler 21. By way of example, a cooler 21 may include a heat exchanger. Such a heat exchanger may be a radiator or equivalent, swept by air set in motion by a fan. By way of example, a heater may include an electrical resistance.

[0091] Furthermore, the main fluid circuit 101 includes a magnetic filter 30 through which the lubricating fluid 4 flows. This magnetic filter 30 is arranged between the reservoir 7 and the fluid spray circuit 12. The magnetic filter 30 is therefore connected by an upstream hydraulic connection 61 to the reservoir 7 and by a downstream hydraulic connection 62 to the fluid spray circuit 12. Optionally, the main fluid circuit 101 includes a filter strainer 17 upstream of the magnetic filter 30. In one example, the main suction inlet is equipped with this filter strainer 17. The filter strainer 17 can be sized to filter large contaminants, such as washers or nuts, to protect the flow generator 11, or even to filter metallic particles resulting from abnormal operation, but it cannot filter metallic powder resulting from normal operation.Any metallic particle to be filtered may have a distance between two points on its outer surface greater than a threshold, while any distance between two points on the outer surface of each particle in the metallic powder must be less than or equal to this threshold. For example, the threshold is 10 microns, with metallic particles typically having dimensions between 0.4 and 1.5 millimeters and the elements of the metallic powder typically having dimensions less than 3 microns.

[0092] The flow generator 11, the magnetic filter 30, the heater 20, the cooler 21 and / or the mechanical filter 25 can be arranged outside the housing 5.

[0093] Furthermore, the magnetic filter 30 includes at least one magnetic wall 32, or even a retarder 31 reducing the speed of movement of the lubricating fluid 4 within the magnetic filter 30 compared to a speed of movement reached at the inlet of the magnetic filter 30.

[0094] For example, the magnetic filter 30 comprises an external tank 35 and a tube 40, possibly at least partially disposed in the external tank 35, as well as an inlet fitting 51 forming an inlet connected to the upstream hydraulic connection 61 and an outlet fitting 52 forming an outlet connected to the downstream hydraulic connection 62.

[0095] For example, the external tank 35 and the tube 40 can be connected to a cover 50 which includes the inlet fitting 51 and the outlet fitting 52.

[0096] The lubricating fluid 4 thus enters the magnetic filter 30 through an inlet passage surface SI. According to the illustrated example, the inlet passage surface SI is to be considered in a plane perpendicular to the direction of movement of the lubricating fluid 4. The inlet passage surface SI can represent the smallest passage area obtained by cutting the inlet fitting 51 with a plane.

[0097] The magnetic filter 30 includes an inlet volume hydraulically connected to the inlet passage surface SL. This inlet volume can be an external volume VEXT between the external tank 35 and the tube 40 or the internal volume VINT delimited by the tube 40. The external volume VEXT or the internal volume VINT not forming the inlet volume is hydraulically connected to the outlet fitting 52.

[0098] Therefore, according to the example of [Fig.1], the upstream hydraulic connection 61 hydraulically connects the reservoir 7 to the external volume VEXT, possibly via the cover 50, and the downstream hydraulic connection 62 hydraulically connects the internal volume VINT to the fluid projection circuit 12, possibly via the cover 50.

[0099] The fluid speed reducer 31 can be formed by an enlarged flow area. Thus, the external volume VEXT can include an external flow area S2 having an area greater than the inlet flow area SL. The external flow area S2 is to be considered in a plane perpendicular to the direction of movement of the lubricating fluid 4, and to the extension axis AX1 as illustrated. The external flow area S2 can represent the smallest flow area obtained by cutting the volume VEXT with a plane.

[0100] Furthermore, the magnetic filter 30 includes at least one intermediate flow surface 41 establishing hydraulic communication between the external volume VEXT and the internal volume VINT. According to the example in [Fig. 1], the tube 40 rests on a bottom 351 of the external tank 35 and extends along an extension axis AX1 from this bottom 351 of the external tank 35. Each intermediate flow surface 41 can then be crossed by a radial axis AX2 perpendicular to the extension axis AX1, favorably near the bottom 351 to ensure that the lubricating fluid 4 circulates along the entire external tank 35 and tube 40.

[0101] For example, the tube 40 is a cylinder with a circular base. For example, a ring of this cylinder has one or more openings forming one or more intermediate passage surfaces 41.

[0102] Furthermore, the magnetic filter 30 has a magnetic wall 32. This magnetic wall 32 comprises the external tank 35 or the tube 40 depending on the embodiment.

[0103] According to the example in [Fig. 1], the tube 40 forms the magnetic wall 32 comprising a hollow magnetic bar 38. Such a bar 38 may comprise a half-cylinder forming a north pole and a half-cylinder forming a south pole. Alternatively, the outer tank 35 may comprise such a hollow magnetic bar 38.

[0104] According to the example in [Fig. 2], the magnetic wall 32 comprises a metal wall 33 attached to one or more permanent magnets 42, at least one permanent magnet optionally extending into the lubricating fluid. According to this [Fig. 2], the metal wall 33 forms the tube 40. Alternatively, the magnetic wall 32 forms the outer tank 35.

[0105] According to the example in [Fig. 3], the magnetic wall 32 comprises a wall 90 made of aluminum alloy. The magnetic wall 32 includes a support 36 attached to this aluminum alloy wall 90 by screwing, gluing, or other means. The support 36 then carries one or more permanent magnets 37. According to [Fig. 3], the metal wall 33 forms the outer tank 35. Alternatively, the magnetic wall 32 forms the tube 40.

[0106] Figures 4 to 6 illustrate various alternative embodiments. In each of the illustrated embodiments, the external tank 35 can be connected to the upstream hydraulic connection 61 and the tube 40 is connected to the downstream hydraulic connection 62, or vice versa.

[0107] According to the examples in Figures 4 and 5, the tube 40 extends into the external tank 35 without touching the bottom, unlike the examples in Figures 1 and 3. The tube 40 and / or the external tank 35 may include a magnetic wall 32.

[0108] According to the example in [Fig.6], the external tank 35 includes a magnetic wall 32.

[0109] As illustrated in [Fig.1] with magnetic filters of these types, the upstream hydraulic connection 61 includes the flow generator 11 connected by piping to the magnetic filter 30. The downstream hydraulic connection 62 includes piping from the magnetic filter 30 to the heater 20 and / or the cooler 21 optional, then piping from the heater 20 and / or the cooler 21 optional and to the mechanical filter 25.

[0110] According to the example in [Fig.7], the magnetic filter 30 and the mechanical filter 25 form a single filtration unit.

[0111] In this case, the upstream hydraulic connection 61 may, for example, include the flow generator 11 connected by piping to the heater 20 and / or the optional cooler 21, and then piping from the heater 20 and / or the optional cooler 21 to the external volume of the filtration unit. The downstream hydraulic connection 62 includes a fitting connecting the filtration unit and the fluid spray circuit 12. An arrangement in place of the magnetic filter of [Fig. 1] is also possible.

[0112] Furthermore, the magnetic wall 32 includes the external tank 35. This external tank 35 can then include a hollow magnetic bar 38, a metal wall attached to one or more permanent magnets, or an aluminum alloy wall attached to a support carrying one or more permanent magnets.

[0113] In addition, the tube 40 includes the porous envelope 28.

[0114] The method implemented according to the invention is explained below on the basis of the realization of [Fig.1], knowing that the other realizations described work in a similar way.

[0115] This process involves circulating STP1 the lubricating fluid 4 in the main fluid circuit 101. At the outlet of the main fluid circuit 101, the lubricating fluid 4 is ejected by the fluid projection circuit 12 and returns to the reservoir 7 by gravity for example.

[0116] In addition, the process includes a depollution step STP21, STP22 of the lubricating fluid 4 circulating in the main fluidic circuit 101 with the magnetic filter 30 and the mechanical filter 25.

[0117] According to the example in [Fig. 1], the lubricating fluid 4 containing metal powder enters the inlet volume, this inlet volume being formed by the external volume VEXT as shown in the example. The flow velocity of the lubricating fluid 4 is possibly reduced due to the passage area S2 of the external volume VEXT being greater than the inlet passage area SL. The magnetic wall 32 attracts this metal powder. Limiting the flow velocity of the lubricating fluid 4 also tends to limit the removal of metal powder from the magnetic wall 31. Optionally, after a period of use of the mechanical system 1, the magnetic filter 30 can be cleaned, all the more easily when this magnetic filter 30 is located outside the housing 5. The lubricating fluid 4 is also subsequently filtered by the porous sleeve 28. The contaminants collected during cleaning can be used to assess the condition of the mechanical system.

[0118] Thus, the magnetic filter 30 and mechanical filter 25 make it possible to decontaminate the lubricating fluid 4. The magnetic plug 80 then captures few magnetic powders.

[0119] If a mechanical element 6 deteriorates, magnetic particles fall or enter the reservoir 7. The optional filter strainer 17 can prevent These magnetic particles enter the magnetic filter 30 or even the main fluidic circuit 101. In addition, the magnetic particles are captured by the magnetic plug 80. This magnetic plug 80 can generate a signal transmitted to the alarm 81 to generate an STP3 alert in the presence of a minimum quantity of metal captured by this magnetic plug 80.

[0120] Naturally, the present invention is subject to numerous variations in its implementation. Although several embodiments have been described, it is understood that it is not conceivable to exhaustively identify all possible embodiments. It is, of course, conceivable to replace a described means with an equivalent means without departing from the scope of the present invention as defined by the claims.

Claims

Demands

1. Mechanical system (1) comprising movable mechanical elements (6) to be lubricated or cooled in a housing (5), the mechanical system (1) having a lubrication system (10) equipped with a reservoir (7) containing a lubricating fluid (4), the lubrication system (10) having a main fluid circuit (101) extending from the reservoir (7) to a fluid spray circuit (12), the main fluid circuit (101) having a flow generator (11) and a mechanical filter (25) equipped with a cartridge (26) having a porous casing (28), the lubrication system (10) comprising a magnetic plug (80), characterized in that the main fluid circuit (101) comprises a magnetic filter (30) through which the lubricating fluid (4) flows between the reservoir (7) and the fluid spray circuit (12), the magnetic filter (30) comprising at least one magnetized wall (32),the magnetic stopper (80) being connected to an alarm (81) to generate an alert in the presence of metal detected by this magnetic stopper (80).

2. Mechanical system according to claim 1, characterized in that the magnetic filter (30) includes a retarder (31) reducing a speed of movement of the lubricating fluid (4) within the magnetic filter (30) compared to a speed of movement reached at the inlet of the magnetic filter (30).

3. A mechanical system according to any one of claims 1 to 2, characterized in that the magnetic filter (30) comprises an outer tank (35) and a tube (40) disposed at least partially within the outer tank (35), an external volume (VEXT) being contained between the outer tank (35) and the tube (40), an internal volume (VINT) being delimited by the tube (40) and in communication with the external volume (VEXT), the main fluid circuit (101) comprising an upstream hydraulic connection (61) extending from the reservoir to an inlet of the magnetic filter (30), said inlet being hydraulically connected to an inlet volume formed by the external volume (VEXT) or the internal volume (VINT), the main fluid circuit (101) comprising a downstream hydraulic connection (62) hydraulically connecting the internal volume (VINT) or the external volume (VEXT) not forming the inlet volume, the magnetic wall (32) including the external tank (35) or the tube (40).

4. Mechanical system according to claims 2 and 3, characterized in that said inlet has an inlet passage surface (SI) through which the lubricating fluid passes, the external volume (VEXT) has an external passage surface (S2) having an area greater than an area of ​​the inlet passage surface (SI) to form said retarder (31).

5. Mechanical system according to any one of claims 3 to 4, characterized in that the tube (40) comprises at least one open intermediate passage surface (41) communicating the external volume (VEXT) and the internal volume (VINT).

6. Mechanical system according to any one of claims 3 to 5, characterized in that the tube (40) comprises said magnetic wall (32).

7. Mechanical system according to any one of claims 3 to 4, characterized in that the magnetic filter (30) and the mechanical filter (25) form a single filter, said magnetic wall (32) comprising the outer tank (35), the tube (40) comprising the porous envelope (28).

8. Mechanical system according to any one of claims 1 to 7, characterized in that the magnetized wall (32) comprises a wall (90) made of aluminum alloy or plastic, the magnetized wall (32) comprising a support (36) fixed to this wall (90) made of aluminum alloy or plastic and provided with at least one permanent magnet (37).

9. Mechanical system according to any one of claims 1 to 7, characterized in that said magnetic wall (32) comprises a metallic wall (33) attached to at least one permanent magnet (42) or comprises a hollow magnetic bar (38).

10. Mechanical system according to any one of claims 1 to 9, characterized in that the main fluidic circuit (101) comprising an upstream hydraulic link (61) going from the reservoir to an inlet of the magnetic filter (30), the upstream hydraulic link (61) comprising said flow generator (11), the downstream hydraulic link (62) comprising at least one of the following equipment: a heater (20), a cooler (21), the mechanical filter (25).

11. Mechanical system according to any one of claims 1 to 10, characterized in that the magnetic filter (30) is arranged outside said housing (5).

12. Mechanical system according to any one of claims 1 to H, characterized in that the mechanical system (1) is a power transmission box (8).

13. Aircraft (2), characterized in that said aircraft (5) comprises a mechanical system (1) according to any one of claims 1 to 12.

14. A method for reducing the number of false alarms within a mechanical system (1) comprising moving mechanical elements (6) to be lubricated or cooled in a housing (5), the mechanical system (1) having a lubrication system (10) equipped with a reservoir (7) containing a lubricating fluid (4), the lubrication system (10) having a main fluid circuit (101) extending from the reservoir (7) to a fluid spray circuit (12), the main fluid circuit (101) having a flow generator (11) and a mechanical filter (25) equipped with a cartridge (26) having a porous casing (28), the lubrication system comprising at least one magnetic plug (80), characterized in that the method comprises the following steps: - circulation of the lubricating fluid (4) in the main fluid circuit (101), the lubricating fluid exiting through the fluid spray circuit (12) and returning to the reservoir (7),- Decontamination of the lubricating fluid (4) circulating in the main fluid circuit (101) with a magnetic filter (30) and the mechanical filter (25), - Generation of an alert with the magnetic plug (80) in the presence of metal captured by this magnetic plug (80).