Mechanical system having mobile mechanical element, magnetic plug and lubrication system having mechanical and magnetic filters

Abstract

The invention relates to a mechanical system (1) comprising a moving mechanical element (6) to be lubricated or cooled in a housing, said mechanical system (1) having a lubrication system (10) provided with a tank (7) containing a lubricating fluid (4), the lubrication system (10) having a main fluid circuit (101) extending from the tank (7) to a fluid injection circuit (12), the main fluid circuit (101) has a flow generator (11), a mechanical filter (25) and a magnetic plug (80). The main fluid circuit (101) comprises a magnetic filter (30) between the tank (7) and the fluid injection circuit (12) through which the lubricating fluid (4) passes, the magnetic filter (30) comprising at least one magnetized wall (32).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of FR 2401391, filed on February 13, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] The invention relates to a mechanical system having a moving mechanical element, a magnetic plug and a lubrication system having a mechanical and magnetic filter.

[0003] Mechanical systems may include moving mechanical elements to be cooled or lubricated, such as shafts, bearings, mechanical elements for transmitting power or for reducing or increasing rotational speed, pinions, wheels, splines, etc.

[0004] For example, a rotorcraft may include rotors that contribute, at least in part, to the lift of the aircraft. To rotate such rotors, a gearbox-type mechanical system may mechanically connect one or more motors to the rotors. Such gearboxes may include mechanical elements that need to be lubricated or cooled.

[0005] Such a mechanical system therefore comprises a lubrication system for delivering lubricating fluid to the mechanical elements in order to lubricate and / or cool them. Such mechanical elements are hereinafter referred to as "mechanical elements to be lubricated or cooled".

[0006] Known lubrication systems include a main fluid circuit. This main fluid circuit contains lubricating fluid held in a tank. This tank is formed, for example, by the bottom of the housing of the mechanical system to be lubricated or cooled. Furthermore, the fluid circuit is provided with a pump that draws fluid from the tank. The pump then moves the fluid to at least one fluid injection circuit, sometimes referred to as a "lubrication manifold" or "fluid injection manifold." The fluid is then discharged from the fluid injection circuit to reach the mechanical element to be lubricated or cooled, after which it returns to the bottom of the housing under the influence of gravity. Furthermore, the main fluid circuit includes a cooler. In contrast to a heater, the term "cooler" refers to a device capable of reducing the temperature of a fluid.

[0007] Furthermore, the lubricating fluid may be contaminated by metallic magnetic contaminants. Therefore, the mechanical system may include mechanical filtering devices to prevent large contaminants (e.g., measuring approximately 10 microns or larger) from particularly clogging the fluid injection circuit and to ensure the reliability of the mechanical contacts.

[0008] Therefore, the filter can be placed upstream of the pump and / or fluid injection circuit. The primary fluid circuit can also include a cartridge filter upstream of the fluid injection circuit. This cartridge filter comprises a container that holds a porous filter cartridge. Fluid enters the container, passes through the housing, and then exits the filter. As a result, any particles larger than the openings in the housing are trapped in the container.

[0009] Optionally, the lubrication system includes only a primary fluid circuit or also includes a backup fluid circuit. In this case, both the primary and backup fluid circuits can be configured to draw lubrication fluid from the same tank and deliver the fluid to the same fluid injection circuit or to separate fluid injection circuits. The purpose of the backup fluid circuit is to allow the mechanical system to operate for at least a predetermined period of time in the event of a failure of the primary fluid circuit. The backup fluid circuit may extend only within the mechanical system housing to prevent leakage outside the mechanical system.

[0010] Furthermore, during operation, mechanical systems may generate metallic magnetic particles due to degradation of at least one of the rotating mechanical elements, for example due to chipping of a pinion or a toothed wheel tooth. These metallic magnetic particles, indicative of a fault, are large, measuring approximately one tenth of a millimeter.

[0011] Due to the abnormal operation of the mechanical system to be detected, the mechanical system often includes a removable magnetic plug to separate, secure, and remove any metal magnetic particles that may have fallen into the tank due to the abnormal operation. The magnetic plug can be connected to a warning system to generate an alarm when a specific amount of metal is captured. The magnetic plug is typically located at the bottom of the tank and captures any metal magnetic particles that fall toward the bottom of the tank. One or more fluid circuits can extract lubricating fluid from the tank through a filter to prevent the ingestion of these metal magnetic particles.

[0012] Furthermore, the lubricating fluid may be contaminated with very fine metallic magnetic particles. Metallic magnetic particles consist of metallic magnetic particles suspended in the lubricating fluid that measure approximately 0.5 to 3 microns and / or are smaller than the perforations in the aforementioned filter screen. This metallic magnetic particle may be generated during the manufacture and / or assembly of the mechanical system, for example through shrink fitting and / or clamping, or by normal friction in the contact areas between the various moving mechanical components of the system. The metallic magnetic particles have no effect on the operation of the mechanical system or its lubrication system, as the powder is expected to be generated by normal operation and due to the very small size of the constituent particles.

[0013] Hereinafter, the term "metal particles" is used to refer to large metallic magnetic contaminants resulting from faults or from manufacturing- or assembly-induced contamination. This encompasses, for example, any metallic magnetic particle where the spacing between two distinct points on the particle is greater than 10 microns. Conversely, the term "metal powder" refers to any metallic magnetic contaminant resulting from manufacturing, assembly, or normal expected wear and tear (e.g., grinding, fretting) of a mechanical system. This encompasses, for example, any contaminant where the spacing between two distinct peripheral points is less than or equal to 10 microns. Furthermore, "metal powder" can be generated during faults, with or without "metal particles."

[0014] When metal powder is present, the mechanical system can continue to be used until its next maintenance, while proactive maintenance action is taken when a certain amount of metal particles is present.

[0015] However, some regulations require the detection of smaller metal particles in a shorter time. To comply with these regulations, magnetic plugs with high magnetic pull can be used.

[0016] Although effective at sensing large metal particles that fall into the tank, such magnetic plugs also attract metal powder suspended in the lubricating fluid in the tank. Consequently, metal powder may cause the magnetic plug to quickly sense large amounts of material, even though this is simply due to normal wear. The flow of fluid in the lubrication system tends to also cause metal powder to flow, which gradually adheres to the magnetic plug. Consequently, magnetic plugs with high magnetic pull may generate false alarms, leading to excessive and expensive maintenance actions. The advantage of such magnetic plugs is that any breakage can be detected and an alarm generated accordingly, but the disadvantage is the potential for false alarms in the medium term due to the plug capturing metal powder passing near it. Furthermore, the presence of metal powder generated by normal operation can delay the capture of metal particles generated by a fault. Background Art

[0017] Document FR3083283B1 describes a mechanical system that, inter alia, features a magnetic plug in a housing and a magnet in a lubrication system. This plug and magnet form a sensing device designed to detect metal particles passing near them. When the lubrication system is operating, metal particles attracted by the magnet are swept away by the lubricating fluid. Therefore, this document provides for the arrangement of a bypass line.

[0018] Document FR 3 100 614 B1 discloses a mechanical system having, in particular, a magnetic plug in a box and a particle counter.

[0019] Document US5089129A discloses a device provided with a magnetic filter and a porous filter.

[0020] Document CN103452619A discloses an automobile engine provided with a magnetic drain plug.

[0021] Document CN208237061U discloses an automobile transmission system provided with a magnetic drain plug. Summary of the Invention

[0022] An object of the present invention is therefore to propose a mechanical system provided with a lubrication system that aims to limit the number of false alarms generated by the use of magnetic plugs.

[0023] The invention relates to a mechanical system comprising a mobile mechanical element to be lubricated or cooled in a housing, the mechanical system having a lubrication system provided with a tank for containing lubricating fluid, the lubrication system having a main fluid circuit extending from the tank to a fluid injection circuit, the main fluid circuit having a flow generator and a mechanical filter provided with a filter cartridge having a porous housing, the lubrication system comprising at least one magnetic plug.

[0024] The magnetic plug(s) are in contact with the lubricating fluid at least during operation. Thus, the magnetic plugs may be arranged, for example, in the tank or in a return path carried by the lubricating fluid between the element to be lubricated or cooled and the tank. At least one magnetic plug may be external to the main fluid circuit.

[0025] For example, the porous housing of such a mechanical filter may include perforated walls that are optionally folded in an accordion fashion to maximize the filtering surface area.

[0026] Furthermore, the lubrication system may also comprise at least one auxiliary fluid circuit. For example, the auxiliary fluid circuit may form a conventional backup circuit partially or completely housed in a housing and / or drawing lubrication fluid from the same tank as the main fluid circuit.

[0027] Furthermore, the main fluid circuit comprises, between the tank and the fluid injection circuit, a magnetic filter through which the lubricating fluid passes, the magnetic filter comprising at least one magnetized wall.

[0028] This mechanical system thus contradicts preconceived notions, as a magnetic filter is provided in addition to the mechanical cartridge filter. Paradoxically, the magnetic plug's purpose is precisely to capture metallic magnetic contaminants present in the lubricating fluid after the lubricated or cooled element has been sprayed, thereby preventing any malfunction. Therefore, at first glance, filtering the lubricating fluid for metallic contaminants might appear counterproductive.

[0029] However, in an innovative approach, it has been observed that false alarms are caused by the presence of a powerful magnetic plug. This plug effectively captures metallic magnetic contaminants present in the tank, including very fine metal powders that are generated over time by manufacturing and normal operation. Therefore, metal powders sensed by the magnetic plug can generate false alarms.

[0030] The invention also includes a magnetic plug with high magnetic pull. When there are no faults, the lubricating fluid flows within the mechanical system and thus through the magnetic filter. Metal contaminants are attracted to the magnetized walls of the magnetic filter.

[0031] During this phase, contaminants are generated solely by the normal operation of the mechanical system. This reduces the amount of metal powder likely to be attracted by the magnetic plug and the risk of false alarms. In turn, the mechanical filter can specifically filter other types of contaminants while being less susceptible to clogging by metallic contaminants than conventional systems. Consequently, the lubricating fluid is effectively purified.

[0032] When an element of the mechanical system experiences a malfunction such as a fracture, large metal particles fall, for example under the effect of gravity, towards the tank and are caught by the magnetic plug. This magnetic plug is always placed upstream of both the mechanical filter and the magnetic filter with respect to the direction of movement of the lubricating fluid from the tank to the fluid injection circuit, in order to limit the risk of losing metal particles in these filters.

[0033] Therefore, the mechanical system associates a magnetic filter with the mechanical filter within the main fluid circuit to at least limit the number of false alarms issued by the magnetic plug. This can potentially reduce downtime costs and operating costs of the mechanical system.

[0034] The mechanical system may also include one or more of the following features, taken alone or in combination.

[0035] According to one possibility, the main fluid circuit may comprise a filtering screen upstream of the magnetic filter or the flow generator.

[0036] The terms "upstream" and "downstream" are to be considered relative to the direction of fluid flow.

[0037] For example, the filter screen is arranged in a tank or at the inlet of the main fluid circuit.

[0038] According to a possibility compatible with the aforementioned one, the magnetic plug can be connected to a warning system.

[0039] The magnetic plug can generate a signal that is transmitted to the warning system. For example, the magnetic plug can then close an electrical circuit that powers the warning system.

[0040] According to a possibility compatible with the aforementioned possibility, the magnetic filter may comprise a speed reducer which reduces the movement speed of the lubricating fluid inside the magnetic filter relative to the movement speed achieved at the inlet of the magnetic filter.

[0041] The primary fluid circuit tends to move the lubricating fluid at high flow rates (e.g., greater than 800 l / h), which might seem advantageous for purifying the lubricating fluid. However, at these flow rates, only metallic magnetic contaminants passing near the magnetized walls are attracted to and adhere to them. A velocity reducer slows the lubricating fluid in the magnetic filter, increasing the chances of metallic contaminants being attracted to the magnetized walls.

[0042] According to a possibility compatible with the aforementioned possibilities, the magnetic filter may comprise an external container and a tube at least partially arranged in the external container, comprising an external volume body between the external container and the tube, the tube defining an internal volume body, the internal volume body being in communication with the external volume body, the main fluid circuit comprising an upstream hydraulic connection from the tank to the inlet of the magnetic filter, said inlet being hydraulically connected to an inlet volume body formed by the external volume body or the internal volume body, the main fluid circuit comprising a downstream hydraulic connection which hydraulically connects the volume body of the internal volume body and the external volume body that does not form the inlet volume body to the fluid injection circuit, the magnetized wall comprising the external container or the tube.

[0043] Optionally, the inlet has an inlet channel surface through which the lubricating fluid passes, and the outer volume body has an outer channel surface whose area is larger than that of the inlet channel surface so as to form the aforementioned speed reducer.

[0044] This approach also has the advantage of being able to increase the magnetic surface area and thus support the capture of metallic magnetic contaminants.

[0045] According to a possibility compatible with the aforementioned possibility, the tube can be cylindrical.

[0046] According to a possibility compatible with the aforementioned possibility, the tube may comprise at least one open intermediate channel surface putting the outer volume in communication with the inner volume.

[0047] According to a first alternative embodiment of the magnetized wall, the magnetized wall may comprise a wall made of an aluminum alloy or a plastic material, comprising a support attached to said aluminum alloy or plastic wall and provided with at least one permanent magnet.

[0048] For example, such a support is in the form of a sheath made of plastic material or the like positioned on an aluminium or plastic wall, the sheath carrying the at least one magnet.

[0049] Aluminum alloys have the advantage of being conductive to magnetic waves, which can enhance the attraction of metallic contaminants.

[0050] Alternatively, the walls may be made of a plastic material.

[0051] The use of a support bearing one or more magnets around a substantially non-magnetic wall facilitates the recovery of collected metallic magnetic contaminants. When the operator removes the magnetic support, the metallic magnetic contaminants are no longer attracted by the magnetic force and fall, making them easier to collect. This arrangement allows for the temporary suppression of magnetic effects on the metallic magnetic contaminants.

[0052] According to a second alternative embodiment of the magnetized wall, the magnetized wall may comprise a metal wall adjoining at least one permanent magnet, or a hollow magnetized rod.

[0053] This second alternative has the advantages of a large magnetized surface and a favorable efficiency / mass ratio.

[0054] According to another aspect, since the main fluid circuit may comprise an upstream hydraulic connection from the tank to the inlet of the magnetic filter, the upstream hydraulic connection may comprise said flow generator and the downstream hydraulic connection may comprise at least one of the following devices: a heater, a cooler, a mechanical filter.

[0055] The flow generator can be located internal or external to the mechanical system.

[0056] The magnetic filter can then be placed downstream of the flow generator. The magnetic filter can be placed upstream of the heater, cooler and / or mechanical filter in order to limit the amount of contaminants delivered to these components and to additionally collect particles in order to characterize and quantify them in the event of a malfunction before they are lost in the mechanical filter and / or cooler and / or heater.

[0057] According to another aspect, and when there is a magnetic filter with an external container and a tube, regardless of how the magnetized wall is obtained, according to a first variant, the tube can comprise a magnetized wall.

[0058] For example, the tube can be magnetized instead of the outer container to optimize the quality of the system.

[0059] According to a second variant, the outer container may comprise a magnetized wall.

[0060] Alternatively, the magnetic filter and the mechanical filter may form one and the same filter, the magnetized wall comprising the outer container and the tube comprising the porous shell.

[0061] The same device then functions as both a magnetic filter and a mechanical filter. Furthermore, by retrofitting the same porous housing onto an existing system, the filter can generate the same head loss as before.

[0062] According to one possibility, at least one magnet or a magnetized sheath can be arranged on the outer container of an existing mechanical filter in order to obtain a magnetized wall.

[0063] According to another aspect, a magnetic filter may be arranged outside the housing.

[0064] This arrangement makes it easy to remove the magnetic filter when necessary. The contents of the magnetic filter can be collected and analyzed to perform health diagnostics on the mechanical system.

[0065] According to another aspect, the mechanical system may be a gearbox.In addition to the mechanical system, the invention also relates to an aircraft comprising such a mechanical system.

[0066] For example, the mechanical system is a gearbox connected to at least one rotor by a mechanical chain in order to rotate it.

[0067] In addition to a mechanical system, the present invention also relates to a method for reducing the number of false alarms in a mechanical system, the mechanical system comprising a mobile mechanical element to be lubricated or cooled in a housing, the mechanical system having a lubrication system provided with a tank containing lubricating fluid, the lubrication system having a main fluid circuit extending from the tank to a fluid injection circuit, the main fluid circuit having a flow generator and a mechanical filter having a filter cartridge provided with a porous housing, the lubrication system comprising at least one magnetic plug. The magnetic plug can be in contact with the lubricating fluid at least during operation, possibly outside the main fluid circuit, for example in the tank or on a return path of the lubricating fluid from the element to be lubricated or cooled to the tank.

[0068] The method comprises the following steps:

[0069] causing lubricating fluid to flow in the main fluid circuit, the lubricating fluid to exit through the fluid injection circuit and return to the tank;

[0070] Purifying the lubricating fluid flowing in the main fluid circuit using a magnetic filter comprising at least one magnetized wall and optionally a speed reducer to reduce the speed of movement of the lubricating fluid and a mechanical filter; and

[0071] When metal is caught by the magnetic plug, an alarm is generated by means of the magnetic plug.

[0072] Said minimum amount can be established by tests or derived, for example, from the regulations to be complied with (eg the “Certification Specifications for Large Helicopters CS-29”). BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The invention and its advantages will become apparent in more detail from the following description of embodiments given by way of illustration with reference to the accompanying drawings, in which:

[0074] . Figure 1 is a diagram illustrating a mechanical system and related method according to the present invention;

[0075] . Figure 2 An example of a magnetized wall provided with a metal tube and at least one magnet is shown;

[0076] . Figure 3 An example of a magnetic filter is shown;

[0077] . Figure 4 An example of a magnetic filter is shown;

[0078] . Figure 5 An example of a magnetic filter is shown;

[0079] . Figure 6 An example of a magnetic filter is shown; and

[0080] . Figure 7 is a diagram showing a filtration unit including a mechanical filter and a magnetic filter. DETAILED DESCRIPTION

[0081] Elements that are present in more than one figure are given the same reference numeral in each of those figures.

[0082] Figure 1 A mechanical system 1 according to the invention is shown. The mechanical system 1 may be arranged in various structures, for example in a vehicle and, according to the example shown, possibly in an aircraft 2. The mechanical system 1 may be a gearbox 8.

[0083] For example, a mechanical system 1 is arranged in an aircraft 2 to rotate, in particular, a rotor 3, possibly by means of an output rotor shaft. Such a rotor 3 may be a main rotor of a helicopter, a rotor contributing to yaw control, a propeller, etc.

[0084] Regardless of the nature of the mechanical system 1 and its arrangement, the mechanical system 1 includes moving mechanical elements 6 to be lubricated or cooled. These mechanical elements 6 to be lubricated or cooled may include elements that move or rotate relative to the housing 5. Each mechanical element 6 to be lubricated or cooled may include, for example, a shaft, a ball bearing mechanism and the like, a power transmission element, an element for reducing or increasing the rotational speed, a pinion, a wheel, a splined component, etc.

[0085] The mechanical element 6 is arranged in an internal volume defined by the housing 5. The housing 5 may comprise a plurality of subassemblies which together define a cavity in which the mechanical element(s) 6 to be lubricated or cooled are arranged.

[0086] The mechanical system 1 further comprises a lubrication system 10. The lubrication system 10 comprises a tank 7 containing a lubricating fluid 4. For example, a subassembly forming the bottom of the housing 5 forms at least a portion of the tank 7. The lubricating fluid 4 may be a lubricating liquid, such as a liquid comprising oil, or any other liquid capable of lubricating and / or cooling the mechanical element 6.

[0087] The lubrication system 10 includes one or more magnetic plugs 80, which may be conventional magnetic plugs, for example. According to the example shown, the magnetic plugs 80 are in contact with the lubricating fluid 4 in the tank 7. Alternatively, the magnetic plugs 80 may be located in the path of the lubricating fluid, for example between the mechanical element 6 to be lubricated or cooled and the tank 7. As an example, the magnetic plugs 80 are attached to the bottom of the tank 7. The magnetic plugs 80 may include a receiver portion in contact with the lubricating fluid 4 and at least one magnetic attraction device to capture metallic magnetic contaminants, in particular metal particles generated by the fragmentation of the mechanical element 6. Such an attraction device may include a permanent magnet. For example, the magnetic plug may be of the type described in patent EP3627032.

[0088] In conventional manner, the magnetic plug 80 may be connected to a warning system 81. Such a warning system 81 may generate a visual alert (e.g., by emitting light using a light emitting diode or the like or displaying one or more characters on a screen), an audible alert via a speaker, and / or a tactile alert (e.g., by means of a vibration unit that vibrates a component held or worn by the individual).

[0089] In order to move the lubricating fluid 4 towards the machine element 6 , the lubricating system 10 comprises a primary fluid circuit 101 and even additionally at least one auxiliary fluid circuit 102 , for example a backup circuit.

[0090] In order to guide the lubricating fluid 4 toward the machine element 6 to be lubricated or cooled, a main fluid circuit 101 extends from the tank 7 to a fluid injection circuit 12. The fluid injection circuit 12 may comprise one or more lines 13 opening at at least one device 14 for injecting the lubricating fluid, which for simplicity is referred to as a "sprayer". Such a sprayer may be, for example, a nozzle or the like, a simple pipe orifice, a system for mixing the lubricating fluid with a gas, etc.

[0091] In general, the term "pipeline" as used above and below may denote a single pipe or a plurality of pipes attached to each other.

[0092] More precisely, the main fluid circuit 101 comprises a flow generator 11 to draw lubricating fluid from the tank 7. The flow generator 11 may comprise a pump or an ejector communicating with the main suction port and which is immersed in the lubricating fluid 4 present in the tank 7 under normal conditions.

[0093] Downstream of the flow generator 11 and upstream of the fluid injection circuit 12, the main fluid circuit 101 includes a mechanical filter 25. The mechanical filter 25 comprises a filter device having a filter cartridge 26 provided with a porous housing 28. The porous housing 28 can form a filter wall comprising small perforations (e.g., measuring approximately 10 to 25 microns or less). The filter cartridge 25 can be disposed within a chamber 27. The lubricating fluid 4 to be filtered enters the filter device and flows into a volume disposed between the chamber 27 and the porous housing 28, passing through the porous housing 28 before exiting the filter device and being filtered. Optionally, the mechanical filter 25 includes a bypass conduit 29 for bypassing the filter device, for example, if the filter device becomes clogged.

[0094] Optionally, the main fluid circuit 101 may include a heater 20 and / or a cooler 21. According to one example, the cooler 21 may include a heat exchanger. Such a heat exchanger may be a radiator blown by air moved by a fan, etc. According to one example, the heater may include a resistor.

[0095] Furthermore, the main fluid circuit 101 includes a magnetic filter 30 through which the lubricating fluid 4 passes. This magnetic filter 30 is positioned between the tank 7 and the fluid injection circuit 12. The magnetic filter 30 is then connected to the tank 7 via an upstream hydraulic connection 61 and to the fluid injection circuit 12 via a downstream hydraulic connection 62. Optionally, the main fluid circuit 101 includes a filter screen 17 upstream of the magnetic filter 30. According to one example, this filter screen 17 is provided at the main intake. The filter screen 17 may be sized to filter large contaminants (such as washers or nuts) to protect the flow generator 11, or to filter metal particles generated by abnormal operation, but not to filter metal powder generated by normal operation. The distance between two points on the outer surface of any metal particle to be filtered may be greater than a threshold value, and any distance between two points on the outer surface of each particle of the metal powder may be less than or equal to the threshold value. For example, the threshold value may be 10 microns, metal particles typically have a size between 0.4 and 1.5 millimeters, and elements of the metal powder typically have a size less than 3 microns.

[0096] The flow generator 11 , the magnetic filter 30 , the heater 20 , the cooler 21 and / or the mechanical filter 25 may be arranged outside the housing 5 .

[0097] Furthermore, the magnetic filter 30 comprises at least one magnetized wall 32 or speed reducer 31 which reduces the movement speed of the lubricating fluid 4 inside the magnetic filter 30 relative to the movement speed achieved at the inlet of the magnetic filter 30 .

[0098] For example, the magnetic filter 30 comprises an outer container 35 and a tube 40 optionally at least partially arranged in the outer container 35 , as well as an inlet coupler 51 forming an inlet connected to an upstream hydraulic connection 61 and an outlet coupler 52 forming an outlet connected to a downstream hydraulic connection 62 .

[0099] For example, outer container 35 and tube 40 may be connected to a cap 50 that includes an inlet coupler 51 and an outlet coupler 52 .

[0100] Therefore, the lubricating fluid 4 enters the magnetic filter 30 through the inlet channel surface S1 of the inlet. According to the example shown, the inlet channel surface S1 is considered to be in a plane perpendicular to the moving direction of the lubricating fluid 4. The inlet channel surface S1 can represent the minimum channel surface obtained by cutting the inlet coupler 51 in a plane.

[0101] The magnetic filter 30 includes an inlet volume hydraulically connected to the inlet channel surface S1. The inlet volume may be an external volume VEXT included between the external container 35 and the tube 40 or an internal volume VINT defined by the tube 40. Of the external volume VEXT and the internal volume VINT, the volume that does not form the inlet volume is hydraulically connected to the outlet coupler 52.

[0102] Therefore, according to Figure 1 In the example, an upstream hydraulic connection 61 hydraulically connects the tank 7 to the external volume VEXT, possibly via the cover 50 , and a downstream hydraulic connection 62 hydraulically connects the internal volume VINT to the fluid injection circuit 12 , possibly via the cover 50 .

[0103] The fluid velocity reducer 31 can be formed by an enlarged channel surface. Thus, the external volume VEXT can include an external channel surface S2 having an area greater than that of the inlet channel surface S1. In the illustrated example, the external channel surface S2 is considered to lie in a plane perpendicular to the direction of movement of the lubricating fluid 4 and the extension axis AX1. The external channel surface S2 can represent the minimum channel surface obtained by cutting the volume VEXT with a plane.

[0104] Furthermore, the magnetic filter 30 comprises at least one intermediate channel surface 41 which puts the external volume VEXT and the internal volume VINT in hydraulic communication. Figure 1 In the example shown in FIG. 3 , the tube 40 rests on the bottom 351 of the outer container 35 and extends from this bottom 351 of the outer container 35 along the extension axis AX1. Each intermediate channel surface 41 can then advantageously be traversed near the bottom 351 by a radial axis AX2 perpendicular to the extension axis AX1, so as to ensure that the lubricating fluid 4 flows along the entire outer container 35 and the tube 40.

[0105] For example, the tube 40 is a cylinder, for example, a ring of which has one or more openings forming one or more intermediate passage surfaces 41 .

[0106] Furthermore, the magnetic filter 30 has a magnetized wall 32. This magnetized wall 32 comprises an outer container 35 or, depending on the embodiment, a tube 40.

[0107] according to Figure 1 In the example of FIG, the tube 40 forms the magnetized wall 32 because it includes a hollow magnetized rod 38. Such a rod 38 may include a half cylinder forming a north pole and a half cylinder forming a south pole. Alternatively, the outer container 35 may include such a hollow magnetic rod 38.

[0108] according to Figure 2 In the example of FIG. 3 , the magnetized wall 32 comprises a metal wall 33 adjacent to one or more permanent magnets 42 , at least one of which may extend in the lubricating fluid. Figure 2 , the metal wall 33 forms the tube 40 . Alternatively, the magnetized wall 32 forms the outer container 35 .

[0109] according to Figure 3 In the example of FIG. 3 , the magnetized wall 32 comprises an aluminum alloy wall 90. Thus, the magnetized wall 32 comprises a support 36 attached to said aluminum alloy wall 90 by screwing, gluing, etc. The support 36 then carries one or more permanent magnets 37. Figure 3 , the metal wall 33 forms the outer container 35 . Alternatively, the magnetized wall 32 forms the tube 40 .

[0110] Figures 4 to 6 Various alternative embodiments are shown.In each of the embodiments shown, the external container 35 can be connected to the upstream hydraulic connection 61 and the pipe 40 to the downstream hydraulic connection 62, or vice versa.

[0111] according to Figure 4 and Figure 5 In the example shown, the tube 40 extends into the outer container 35 without touching the bottom, Figure 1 and Figure 3 The tube 40 and / or the outer container 35 may include a magnetized wall 32.

[0112] according to Figure 6 In the example shown, the outer container 35 comprises a magnetized wall 32 .

[0113] As with these types of magnetic filters Figure 1As shown, the upstream hydraulic connection 61 includes the flow generator 11 connected by a pipeline to the magnetic filter 30. The downstream hydraulic connection 62 includes a pipe starting from the magnetic filter 30 and connected to the heater 20 and / or cooler 21 (if present), and a pipe starting from the heater 20 and / or cooler 21 (if present) and connected to the mechanical filter 25.

[0114] according to Figure 7 In the example shown, the magnetic filter 30 and the mechanical filter 25 form the same filter unit.

[0115] In this case, according to an example, the upstream hydraulic connection 61 may comprise a line connected to the flow generator 11 via a heater 20 and / or cooler 21 (if present), and a line leaving the heater 20 and / or cooler 21 (if present) and connected to the external volume of the filter unit. The downstream hydraulic connection 62 may comprise a coupling connecting the filter unit to the fluid injection circuit 12. Instead Figure 1 An arrangement of magnetic filters is also possible.

[0116] Furthermore, the magnetized wall 32 comprises an outer container 35. This outer container 35 may then comprise a hollow magnetized rod 38, a metal wall adjacent to one or more permanent magnets or an aluminum alloy wall adjacent to a support carrying one or more permanent magnets.

[0117] Furthermore, the tube 40 includes a porous shell 28 .

[0118] The following is based on Figure 1 The embodiment described is used to explain the method implemented according to the present invention, and it should be understood that the other embodiments described operate in a similar manner.

[0119] The method includes flowing lubricating fluid 4 in the main fluid circuit 101 (STEP 1). For example, at the outlet of the main fluid circuit 101, the lubricating fluid 4 is injected by the fluid injection circuit 12 and returns to the tank 7 under the action of gravity.

[0120] Furthermore, the method includes steps STEP 21 and STEP 22 of purifying the lubricating fluid 4 flowing in the main fluid circuit 101 using the magnetic filter 30 and the mechanical filter 25 .

[0121] according to Figure 1In the example in FIG, a lubricating fluid 4 containing metal powder enters an inlet volume, which, according to the example, is formed by an external volume VEXT. Since the channel surface S2 of the external volume VEXT is larger than the inlet channel surface S1, the movement speed of the lubricating fluid 4 is optionally reduced. The magnetized wall 32 attracts the metal powder. Limiting the movement speed of the lubricating fluid 4 also tends to limit the tearing off of the metal powder from the magnetized wall 31. Optionally, at the end of the operating phase of the mechanical system 1, the magnetic filter 30 can be cleaned, and when the magnetic filter 30 is located outside the housing 5, the magnetic filter 30 can be cleaned more simply. The lubricating fluid 4 is then also filtered by the porous shell 28. The contaminants collected during the cleaning can be used to assess the condition of the mechanical system.

[0122] Thus, the magnetic filter 30 and the mechanical filter 25 allow the lubricating fluid 4 to be purified. Consequently, the magnetic plug 80 senses very little magnetic powder.

[0123] If the mechanical element 6 degrades, magnetic particles can fall into or reach the tank 7. The optional filter screen 17 can prevent these magnetic particles from entering the magnetic filter 30 or the main fluid circuit 101. In addition, the magnetic particles are captured by the magnetic plug 80. When the magnetic plug 80 senses the smallest amount of metal, it can generate a signal that is transmitted to the warning system 81 to generate an alarm STEP 3.

[0124] Needless to say, the implementation of the present invention can be varied in many ways. Although several embodiments have been described above, it should be readily understood that it is not possible to identify all possible embodiments exhaustively. Of course, any of the described means can be replaced with equivalent means without departing from the scope of the present invention as defined in the claims.

Claims

1. A mechanical system (1) comprising a mobile mechanical element (6) to be lubricated or cooled in a housing (5), the mechanical system (1) having a lubrication system (10), the lubrication system (10) being provided with a tank (7) containing a lubricating fluid (4), the lubrication system (10) having a main fluid circuit (101) extending from the tank (7) to a fluid injection circuit (12), the main fluid circuit (101) having a flow generator (11) and a mechanical filter (25), the mechanical filter (25) being provided with a filter cartridge (26) having a porous shell (28), the lubrication system (10) comprising a magnetic plug (80), The main fluid circuit (101) comprises a magnetic filter (30) between the tank (7) and the fluid injection circuit (12), the lubricating fluid (4) passes through the magnetic filter (30), the magnetic filter (30) comprises at least one magnetized wall (32), and the magnetic plug (80) is connected to a warning system (81) for generating an alarm when metal is caught by the magnetic plug (80).

2. The mechanical system according to claim 1, wherein the magnetic filter (30) comprises a speed reducer (31) which reduces the movement speed of the lubricating fluid (4) inside the magnetic filter (30) relative to the movement speed reached at the inlet of the magnetic filter (30).

3. The mechanical system according to claim 1, wherein the magnetic filter (30) comprises an external container (35) and a tube (40) at least partially arranged in the external container (35), an external volume (VEXT) is included between the external container (35) and the tube (40), the tube (40) defines an internal volume (VINT) and the internal volume (VINT) communicates with the external volume (VEXT), the main fluid circuit (101) comprises an upper portion from the tank to the inlet of the magnetic filter (30) A downstream hydraulic connection (61) is provided, wherein the inlet is hydraulically connected to an inlet volume formed by the external volume (VEXT) or the internal volume (VINT), the main fluid circuit (101) comprises a downstream hydraulic connection (62) which hydraulically connects the volume of the internal volume (VINT) and the external volume (VEXT) which does not form the inlet volume to the fluid injection circuit (12), and the magnetized wall (32) comprises the external container (35) or the tube (40).

4. The mechanical system according to claim 2, wherein the magnetic filter (30) comprises an external container (35) and a tube (40) at least partially arranged in the external container (35), an external volume (VEXT) being included between the external container (35) and the tube (40), the tube (40) defining an internal volume (VINT) and the internal volume (VINT) communicating with the external volume (VEXT), the main fluid circuit (101) comprising an upstream hydraulic connection (61) from the tank to an inlet of the magnetic filter (30), the inlet being hydraulically connected to a fluid formed by the external volume (VEXT) or the internal volume (VINT). The main fluid circuit (101) comprises an inlet volume body formed by the inner volume body (VINT) and the outer volume body (VEXT), and the downstream hydraulic connection (62) hydraulically connects the volume body that does not form the inlet volume body of the inner volume body (VINT) and the outer volume body (VEXT) to the fluid injection circuit (12), the magnetized wall (32) comprises the outer container (35) or the tube (40), and wherein the inlet has an inlet channel surface (S1) through which the lubricating fluid passes, and the outer volume body (VEXT) has an outer channel surface (S2), the area of which is larger than the area of the inlet channel surface (S1) so as to form the speed reducer (31).

5. Mechanical system according to claim 3, wherein the tube (40) comprises at least one open intermediate channel surface (41) placing the external volume (VEXT) in communication with the internal volume (VINT).

6. The mechanical system of claim 3, wherein the tube (40) includes the magnetized wall (32).

7. Mechanical system according to claim 3, wherein the magnetic filter (30) and the mechanical filter (25) form one and the same filter, the magnetized wall (32) comprising the outer container (35) and the tube (40) comprising the porous shell (28).

8. Mechanical system according to claim 1, wherein the magnetized wall (32) comprises a wall (90) made of an aluminum alloy or plastic material, the magnetized wall (32) comprising a support (36) attached to the aluminum alloy or plastic material wall (90) and provided with at least one permanent magnet (37).

9. The mechanical system of claim 1, wherein the magnetized wall (32) comprises a metal wall (33) adjacent to at least one permanent magnet (42), or comprises a hollow magnetized rod (38).

10. The mechanical system of claim 1, wherein: Since the main fluid circuit (101) comprises an upstream hydraulic connection (61) from the tank to the inlet of the magnetic filter (30), the upstream hydraulic connection (61) comprises the flow generator (11) and the downstream hydraulic connection (62) comprises at least one of the following devices: a heater (20), a cooler (21), the mechanical filter (25).

11. The mechanical system according to claim 1, wherein the magnetic filter (30) is arranged outside the housing (5).

12. The mechanical system according to claim 1, wherein the mechanical system (1) is a gearbox (8).

13. An aircraft (2), wherein the aircraft (5) comprises a mechanical system (1) according to claim 1.

14. A method for reducing the number of false alarms in a mechanical system (1), the mechanical system (1) comprising a mobile mechanical element (6) to be lubricated or cooled in a housing (5), the mechanical system (1) having a lubrication system (10), the lubrication system (10) being provided with a tank (7) containing a lubricating fluid (4), the lubrication system (10) having a main fluid circuit (101) extending from the tank (7) to a fluid injection circuit (12), the main fluid circuit (101) having a flow generator (11) and a mechanical filter (25), the mechanical filter (25) being provided with a filter cartridge (26) having a porous shell (28), the lubrication system comprising at least one magnetic plug (80), The method comprises the following steps: causing the lubricating fluid (4) to flow in the main fluid circuit (101), the lubricating fluid to exit through the fluid injection circuit (12) and return to the tank (7); using a magnetic filter (30) and the mechanical filter (25) to purify the lubricating fluid (4) flowing in the main fluid circuit (101); and When metal is caught by the magnetic plug (80), an alarm is generated by means of the magnetic plug (80).

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