SET AND METHOD FOR THE DETECTION OF FILLINGS

Abstract

ASSEMBLY AND METHOD FOR DETECTING FILLINGS One aspect of the invention relates to an assembly (E) comprising a closed rotating enclosure (1), a mechanical system (2) and a lubrication circuit (3) passing through the rotating enclosure (1), the enclosure comprising an outer wall (11) of revolution about axis X and an inner wall (10) opposite the outer wall (11), it is characterized in that it comprises a magnetic sensor (5) and that the inner wall (10) comprises n cavities (12) uniformly distributed circumferentially, such that n ≥ 2. Figure to be published with the abstract: Figure 2

Description

Title of the invention: ASSEMBLY AND METHOD FOR THE DETECTION OF FILLINGS TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of mechanical transmissions and more particularly rotary transmissions.

[0002] The invention relates in particular to those with lubrication in a closed rotating enclosure. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Mechanical transmissions, like all moving parts, are subject to wear during their service life, for example, due to friction resulting from contact between two gears or two bearings, or due to shocks or intense friction between rotating parts caused by intense and / or abnormal vibrations. Whatever its cause, wear of the parts leads to the formation of particles that detach from the parts and are carried away by the lubricating fluid. Since rotating parts are generally metallic, the particles resulting from wear are conductive and are generally in the form of metal filings (metallic particles). These parts are most often made of a ferromagnetic metal such as iron, that is, a metal capable of being attracted to a magnetic element such as a magnet. These metal filings make it possible to detect wear or damage to a part.Furthermore, this metal filings also degrade the lubricating properties of the lubricant, so it is important to remove it.

[0004] As described in French patent FR 2 957 823, a magnetic plug is used to trap the metal filings, which can then be removed from the lubrication circuit by removing the plug and dispensing the filings. In the case of rotating parts, a rotating mechanical magnetic plug (mounted on the rotating parts) can be used, but this is cumbersome to implement. An electrical magnetic plug can also be used when the mechanical system to be lubricated is critical.

[0005] It is also possible to mount an electric magnetic stop on a rotating part, but this is very restrictive because it requires the use of a rotating collector: which is bulky and unreliable.

[0006] Detecting metal shavings is essential for detecting potential damage to rotating mechanical components (bearings / gears / mechanical transmission components). This function is currently performed by magnetic plugs, whether electrical or not. The magnetic plug is strategically positioned in the oil circuit, and the magnetic interaction The magnet in the plug captures particles carried by the lubricating fluid. The mechanical magnetic plug is a simple magnet that captures these particles. It is checked manually or visually by an operator during maintenance.

[0007] The electric magnetic plug consists of a magnet and two electrodes electrically insulated from each other. The accumulation of metal filings under the effect of magnetic interaction forms a conductive bridge between the two electrodes. Suitable electronics allow a warning light to be displayed on the instrument panel, thus alerting the user or the pilot in the case of an aircraft. However, for these systems to function, the particles must be transported (by the lubricating fluid) to the magnetic plug.

[0008] In certain cases, such as on a rotating shaft, lubrication requires that the oil be kept in a closed rotating chamber. An oil level is maintained by centrifugal force, and a minimum quantity of oil is retained in the chamber even when the system is stopped. This operation hinders the detection of metal shavings: the oil retention also results in the retention of any particles generated within the chamber. The shavings are not transported to the magnetic plug and are therefore not detected. Summary of the invention

[0009] The invention offers a solution to the problems mentioned above, by allowing the collection of the filings and the measurement of their quantity in the lubrication circuit.

[0010] The assembly according to the invention comprises a closed rotating enclosure, a mechanical system and a lubrication circuit passing through the rotating enclosure, the enclosure comprising an outer wall of revolution with axis X and an inner wall opposite the outer wall, it is characterized in that it comprises a magnetic sensor and that the inner wall comprises n cavities uniformly distributed circumferentially, such that n > 2.

[0011] The filings can thus be concentrated locally in these cavities by centrifugal force. The higher the number n of reservoirs, the lower the concentration of filings will be per cavity. To limit the effects related to imbalance, there will be at least two diametrically opposed cavities, or more cavities uniformly distributed around the periphery of the inner wall.

[0012] Advantageously, the magnetic sensor is a variable reluctance inductive sensor. This sensor makes it possible to detect the passage of filings as well as metallic particles.

[0013] Advantageously, the cavities are surrounded by a conical shape directed towards each cavity. This conical shape consists of slopes that guide the filings towards the cavities by centrifugal effect.

[0014] Advantageously, the cavities have a conical rim. This rim allows the filings to be directed towards the bottom of the cavity by centrifugal force on one side and to be retained when they are in the cavity on the other side.

[0015] Advantageously, the inner wall has an elliptical cross-section along the X-axis, and the cavities are located at the vertices of the ellipse. The elliptical shape of the inner wall, combined with the centrifugal force, will cause the filings to accumulate towards the apogee, that is, the vertex of the ellipse defined as the ends of the major axis, or major axis of the ellipse. The position of the cavities at this location optimizes the accumulation of the filings.

[0016] Advantageously, the cavities have bottoms made of non-magnetic material. The magnetic permeability of the material used to make the bottom of the cavity allows for good transmission of the magnetic field in the lubrication circuit. For example, a plastic material or another non-metallic material can be used. To reduce the air gap between the sensor and the filings, the thickness of the material at the bottom of the boss should be as small as possible, between 0.5 and 5 mm.

[0017] Advantageously, the magnetic sensor is fixed. The cavities and the centrifugal force allow the filings to be grouped in certain defined locations without requiring a magnetic field to concentrate them; therefore, it is possible to use a static magnetic sensor.

[0018] Advantageously, the sensor is fixed to a housing surrounding the enclosure.

[0019] Advantageously, the lubricant of the lubrication circuit is oil.

[0020] The invention also relates to a method for measuring the quantity of filings in an assembly having at least one of the preceding characteristics, and where a cavity, upon passing in front of the inductive sensor, creates an electrical signal in said inductive sensor with an amplitude proportional to the quantity of filings, for example iron, in that cavity. It is thus possible to display an indicator light on the dashboard to warn the user when the concentration of filings is too high.

[0021] Other advantages may become apparent to those skilled in the art upon reading the examples below, illustrated by the accompanying figures, which are given for illustrative purposes. BRIEF DESCRIPTION OF THE FIGURES

[0022] The figures are presented by way of illustration and in no way limit the invention.

[0023] [Fig. 1] is a longitudinal section of a closed enclosure of the prior art;

[0024] [Fig.2] is a longitudinal section of a closed enclosure according to the invention;

[0025] [Fig.3] is an axial cross-sectional view of a closed enclosure according to a first example of the invention;

[0026] [Fig.4] is a detail of a cavity in [Fig.3];

[0027] [Fig.5] is a detail of a variant of the cavity of [Fig.3]

[0028] [Fig.6] is the electrical signal from the variable reluctance sensor during the rotation of the enclosure. DETAILED DESCRIPTION

[0029] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0030] Throughout this description, the inner part of the enclosure will be referred to as the "interior," and the outer part of the enclosure as the "exterior." An enclosure whose only openings are the lubricant inlet and outlet will be called a "closed enclosure."

[0031] The term “limaille” may be used interchangeably in the singular or plural.

[0032] Assembly E of the prior art illustrated [Fig. 1] comprises a closed enclosure 1, a mechanical system 2 to be lubricated, and a lubrication circuit 3. The enclosure 1 and the mechanical system 2 rotate about an axis X. The enclosure includes an inner wall 10 and an outer wall 11. The lubrication circuit 3 includes an inlet 30 for the supply of lubricant, for example, oil, the interior of the enclosure 1 with a lubrication zone 31, and a lubricant outlet 32. The lubricant is injected into the closed enclosure 1; by centrifugal force, the lubricant is pushed towards the lubrication zone 31, and the excess lubricant is discharged through the outlet 32.

[0033] The mechanical parts constituting the mechanical system 2 will wear down with use and release particles into the lubricant, forming filings 4. These particles are, for example, iron filings or any other ferromagnetic material. The function of the lubrication circuit 3 is to lubricate the moving parts (typically rotating parts). However, the presence of particles in the lubricant can accelerate the wear of the mechanical parts and / or be an indicator of abnormal wear of the mechanical system.

[0034] Due to the rotation of the enclosure 1 and the mechanical system 2, the lubricant will adhere to the inner wall 10 of the enclosure 1 in the lubrication zone 31. The metal filings 4 present in the lubricant will also adhere to the inner wall 10 and cannot be removed with the lubricant, as the lubricant inlet 30 and outlet 32 ​​are located on the X-axis. The lubricant remaining in the lubrication zone 31 is therefore always contaminated, and a magnetic plug located after the circuit outlet will not be able to collect them.

[0035] The enclosure 1 according to the invention, visible [Fig. 2], has cavities 12 on the periphery of the inner wall 10. These cavities 12 are uniformly distributed over a periphery 120 of said inner wall 10, so as not to create an imbalance during the rotation of the assembly E. In this example, there is only one periphery 120 with cavities 12 shown, but several can be provided along the enclosure 1 without departing from the scope of the present invention. Thus, in this example, cavities 12 can be present on both a cylindrical portion C2 and a conical portion C2 of the enclosure 1.

[0036] Each cavity 12 is surrounded by a conical part 121 with slopes inclined axially and radially towards the cavity and which allows the filings 4 to be directed towards said cavity 12.

[0037] To further facilitate the orientation of the filings 4 towards the cavities 12, the shape of the axial section of the inner wall 10 of the enclosure 1 can be adapted. Thus, in the example of [Fig. 2], the wall 10 has an oval shape with two cavities 12 arranged at the two vertices of the ellipse. The term "vertex of the ellipse" refers to the two vertices of its major axis. With more than two cavities 12 on a periphery 120, the axial profile can be adapted to the number of cavities 12; thus, for three cavities, a triangular shape can be used, for four, a square shape, and so on.

[0038] In detail A of cavity 12, visible [Fig.4], it can be seen that the oval shape facilitates the guidance of the filings 4 in cavity 12. In the example of [Fig.5], the cavity 12 is surrounded by a rim 122. This rim 122 has a conical edge 1221 on the side of the interior of the enclosure 1 and a straight edge 1220 on the side of cavity 12, in this way the filings 4 can easily enter cavity 12 but are partially retained in the cavity when the enclosure 1 no longer rotates and the filings 4 are no longer pressed against the bottom of cavity 12 by centrifugal force.

[0039] A sensor 5 capable of detecting the passage of ferromagnetic particles 4 is fixed to the outside of the enclosure 1 on a static support, such as a housing (not shown). This sensor may be a variable reluctance inductive sensor. The sensor 5 will emit an electrical signal 50 which will vary when a cavity 12, containing filings, passes in front of said sensor 5. This variation 51, visible [Fig. 6], has an amplitude H proportional to the quantity of filings 4 in the cavity 12. In this way, the user can be informed when the quantity of filings 4 is critical.

[0040] The sensor 5 is placed opposite a periphery 120 where the cavities 12 are aligned so as to be able to measure the quantity of filings present in said cavities 12. The sensor 5 is adjusted to take into account the number of cavities 12 on the periphery 120 opposite which the sensor 5 is placed, indeed, the higher the number of cavities 12 the lower the concentration of filings per cavity.

[0041] The thickness of the enclosure between the bottom of the cavity 12 and the outer wall 11 will be as thin as possible in order to reduce the air gap between the sensor 5 and the filings 4. The material constituting the bottom of cavity 12 or the entire enclosure is non-magnetic to have good magnetic permeability.

[0042] We will now describe the measurement method. During operation, the mechanical system 2 rotates with the closed enclosure 1. The mechanical parts constituting the mechanical system 2 will wear down with use and release filings 4 into the lubrication circuit 3. The centrifugal force created by the rotation will press the filings 4 towards the inner wall 10 of the enclosure 1. The inclination of the slopes surrounding the cavities 12, possibly combined with the shape of the inner wall 10, will concentrate the filings 4 towards the cavities 12. The sensor 5, positioned on a periphery 120, will measure a variation 51 in amplitude H of the electrical signal 50 as a cavity 12 passes in front of said sensor 5, making it possible to measure the quantity of filings 4 in the lubricant. The amplitude H is proportional to the quantity of filings present in a cavity 12.It is possible that some cavities are less filled than others on the periphery 120; a calculator can calculate an average on the number of cavities present on said periphery 120.

[0043] When the sensor 5 identifies that the quantity of filings is becoming critical, the user can be informed.

[0044] The invention allows the separation of the filings from the lubricant by centrifugation and the trapping of the filings.

Claims

Demands

1. Assembly (E) comprising a closed rotating enclosure (1), a mechanical system (2) and a lubrication circuit (3) passing through the rotating enclosure (1), the enclosure comprising an outer wall (11) of revolution about axis X and an inner wall (10) opposite the outer wall (11), characterized in that it comprises a magnetic sensor (5) and the inner wall (10) comprises n cavities (12) uniformly distributed circumferentially, such that n > 2.

2. Assembly (E) according to claim 1, characterized in that the magnetic sensor (5) is a variable reluctance inductive sensor.

3. Assembly (E) according to any one of the preceding claims, characterized in that the cavities (12) are surrounded by a conical shape directed towards each cavity.

4. Assembly (E) according to any one of the preceding claims, characterized in that the cavities (12) have a conical rim.

5. Assembly (E) according to any one of the preceding claims, characterized in that the inner wall (10) has an elliptical cross-section along the X axis and that the cavities (12) are placed at the vertices of the ellipse.

6. Assembly (E) according to any one of the preceding claims, characterized in that the cavities (12) have bottoms of non-magnetic material.

7. Assembly (E) according to any one of the preceding claims, characterized in that the magnetic sensor (5) is fixed.

8. Assembly (E) according to the preceding claim, characterized in that the magnetic sensor (5) is fixed to a housing surrounding the enclosure.

9. Assembly (E) according to any one of the preceding claims, characterized in that the lubricant of the lubrication circuit (3) is oil.

10. Method for measuring the quantity of filings (4) in an assembly (E) according to any one of claims 2 to 6, characterized in that a cavity (12), when passing in front of the inductive sensor (5), creates an electrical signal (50) in said inductive sensor (5) with an amplitude (H) proportional to the quantity of filings (4) in this cavity.

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