阅读说明：本技术 用于检测金属颗粒的磁检测器的磁头和具有该磁头的磁检测器 (Magnetic head of magnetic detector for detecting metal particles and magnetic detector having the same ) 是由 大卫·科索莱托 帕特里克·波旁 丹尼斯·辛德辛格 于 2020-01-21 设计创作，主要内容包括：所述用于检测液压回路中金属颗粒的磁检测器的磁头(11)包括轴向本体(14)、至少一个第一电极(17、18)以及用于电极的电连接的装置(C),轴向本体(14)内部包括至少一个磁体(15、16),第一电极(17、18)限定位于磁体所产生的磁场中的间隙区(E),使得回路在间隙区中形成颗粒的排列区。磁体是径向磁化的磁体。(The magnetic head (11) of a magnetic detector for detecting metal particles in a hydraulic circuit comprises an axial body (14), at least one first electrode (17, 18) and means (C) for electrical connection of the electrodes, the axial body (14) comprising internally at least one magnet (15, 16), the first electrode (17, 18) defining a gap zone (E) in the magnetic field generated by the magnet, so that the circuit forms an alignment zone of particles in the gap zone. The magnet is a radially magnetized magnet.)

1. A magnetic head (11) for the magnetic detection of metal particles in a hydraulic circuit, characterized in that it comprises: -an axial body (14), -at least one first electrode (17, 18) and-means (C) for the electrical connection of the electrodes, said axial body (14) comprising internally at least one magnet (15, 16), said first electrode (17, 18) defining a gap zone (E) in the magnetic field generated by the magnet, so that the circuit forms an alignment zone of the particles in the gap zone, characterized in that said magnet (15, 16; 35) is a radially magnetized magnet.

2. A magnetic head as claimed in claim 1, characterized in that the magnetic head comprises: at least two radially magnetized magnets (15, 16) axially arranged in extension of each other and spaced apart from each other so that the poles of one magnet are disposed opposite the opposite poles of the other magnet, and at least two electrodes disposed respectively around the magnets.

3. A magnetic head as claimed in claim 2, characterized in that at least one electrode is connected to the body by means of a threaded fastener.

4. A magnetic head as claimed in claim 1, characterized in that the electrode comprises a set of notches (37), each notch comprising two facing conductive areas and each notch defining a gap.

5. A magnetic head as claimed in claim 4, characterized in that the magnet is electrically conductive and forms one of the poles of the magnetic head.

6. A magnetic head as claimed in claim 1, characterized in that each of said electrodes comprises a set of teeth (51) extending axially from a support (55), said electrodes being arranged coaxially within each other around the magnet, such that the teeth of one electrode are arranged between the teeth of the other electrode with an insulator arranged therebetween.

7. A magnetic head as claimed in any one of claims 1 to 6, characterized in that each of the electrodes is formed of an electrically conductive material coated with an insulating material and has an electrically conductive region without an insulator at the gap region (E) and at the electrical connection means (C) of the electrodes.

8. A magnetic head as claimed in claim 7, characterized in that the insulation is provided by overmoulding of an insulating material.

9. A magnetic head as claimed in any one of claims 1 to 8, characterized in that it comprises fixing means (28,29) for fixing the magnetic head to the container and locking means (30,31) for locking the fixing means.

10. A magnetic head as claimed in claim 9, characterized in that the fixing means (28,29) comprise snap fixing means and the locking means (30,31) comprise a locking ring which prevents the snap fixing means from rotating.

11. A magnetic head as claimed in any one of claims 1 to 10, characterized in that the magnet is a neodymium permanent magnet.

12. A magnetic detector of metal particles in a hydraulic circuit, comprising: a magnetic head as claimed in any one of claims 1 to 11, and a container (12) for accommodating the magnetic head.

13. A magnetic detector according to claim 12, wherein the container comprises an end cap (24) in which a magnet is housed.

14. A magnetic detector according to claim 13 wherein the end cap (24) of the container constitutes one electrode of the magnetic detector and comprises a set of notches (45), each of said notches defining a gap, each of said notches comprising two facing conductive areas.

15. A magnetic detector according to claim 13, wherein the end cap comprises a valve (25) biased to a closed state, the valve being actuatable to an open state under the action of the magnetic head (11).

Technical Field

The invention relates to a magnetic detector for metal particles that may be present in a hydraulic circuit.

The invention relates in particular to the magnetic detection of metal particles in an engine or gearbox.

The present invention more particularly relates to a magnetic head mounted in a magnetic detector, and a magnetic detector having such a magnetic head.

In a particularly interesting application of the invention, the magnetic detector is used to detect metal particles in the hydraulic circuit of an aircraft, in particular by analysis to detect possible wear of mechanical parts.

Background

In the prior art, magnetic detectors use magnetic heads comprising, on the one hand, one or more magnets, at least two electrodes made of electrically conductive material insulated from each other and arranged close to the magnets, the gaps of such magnets being located in the magnetized zones of the magnets, and, on the other hand, an insulator ensuring the electrical insulation of the electrodes.

The insulator is generally tubular and is disposed around the magnet. The electrodes are electrically connected to a computer of the aircraft.

If metal particles are present, they will be attracted to the magnet. If a sufficient number of particles are present in the gap region, the resistance between the electrodes will decrease. The aircraft computer detects the drop in resistance and its signal is transmitted to the aircraft pilot.

Fig. 1 shows an embodiment of a conventional metal particle magnetic detector.

For example, the detector mounted in a tank comprises a magnetic head 1, the magnetic head 1 being mounted in a container 2 and comprising two magnets 3 and 4, the magnets 3 and 4 being surrounded by tubular electrodes 5 and 6, respectively, and separated by a gap 7.

In the embodiment of fig. 1, the gap 7 is an axial gap.

As shown in fig. 2, magnetic detectors are also known, the head of which is provided with a radial gap.

It is seen that the magnetic head here comprises a ring magnet. One electrode 5 is an axial electrode and the other electrode 6 is arranged around the magnet. The gap thus extends radially, taking into account the general axis of the head.

The overall efficiency of particle magnetic Detectors, commonly referred to as Bouchons Magnitiques Electric (BME) or "electric Chip Detectors" (ECD) in english, has proven to be very low.

This inefficiency is due to certain parameters that affect the capture and detection of metal particles.

The problem is particularly in the turbulent flow region, where the oil flows out of the magnetic field of action of the detector. Or in general the problem is the nature of the lubrication system.

The low collection rate of metal particles is also due to the intrinsic properties of the magnet and the overall volume of the head, which limits the area of particle capture.

Disclosure of Invention

It is therefore an object of the present invention to overcome all or part of the disadvantages present in the use of magnetic heads according to the prior art, in particular to increase the power of the magnetic field generated by the magnet, in order to increase the particle capture rate and the concentration of particles in the gap.

Thus, according to a first aspect, the invention proposes a magnetic head for the magnetic detection of metal particles in a hydraulic circuit, comprising an axial body, inside which there is at least one magnet, at least one first electrode defining a gap region in the magnetic field generated by the magnet, and means for the electrical connection of the electrodes, so that the circuit forms an alignment zone of the particles in the gap region.

The magnet is a radially magnetized magnet.

This radial magnetization enables to position the strongest magnetic field area, i.e. the magnetic pole, in the region of the fluid containing the particles to be captured and thus to obtain a higher particle capture rate.

In one embodiment, the magnetic head comprises at least two radially magnetized magnets axially aligned within the extension of each other and spaced apart from each other such that the poles of one magnet are disposed opposite the opposite poles of the other magnet, and at least two electrodes disposed respectively around the magnets.

In various embodiments, at least one of the electrodes is fixed to the axial body by a screw.

In another embodiment, the electrode surrounds the magnet and includes a set of notches, each notch including two facing conductive regions and each notch circumscribing a gap.

The magnet may be an electrical conductor and constitute one of the poles of the magnetic head.

In another embodiment, each electrode includes a set of teeth extending axially from the support, the electrodes being coaxially disposed within each other about the magnet such that the teeth of one electrode are disposed between the teeth of the other electrode with an insulator disposed therebetween.

In various embodiments, each electrode may be implemented by a conductive material coated with an insulating material and having a conductive region without an insulator at the gap region and at the electrical connection means of the electrode.

For example, the insulation is formed by overmolding of an insulating material.

In various embodiments, it is preferable that the magnetic head includes a fixing device for fixing the magnetic head on the case and a locking device for locking the fixing device.

For example, the fixing means comprise snap fixing means and the locking means comprise a locking ring capable of preventing rotation of the snap fixing means.

Preferably, the magnet is a permanent magnet made of neodymium iron boron (NdFeB).

It is also an object of the present invention to provide a magnetic detector of metal particles in a hydraulic circuit comprising a magnetic head as defined above and a container housing said magnetic head.

In one embodiment, the container includes an end cap in which the magnet is received.

For example, the end cap of the container constitutes one electrode of the magnetic detector and comprises a set of notches, each defining the extent of the gap, each notch comprising two facing conductive areas.

Preferably, the end cap includes a valve biased to a closed state, the valve being actuatable to an open state by the magnetic head.

Drawings

Other objects, features and advantages of the present invention will become apparent from the following description, given by way of example only, and made with reference to the accompanying drawings, in which:

fig. 1, 2 already mentioned, show two embodiments of a magnetic detector according to the prior art, with an axial gap and a radial gap, respectively;

fig. 3 shows a first embodiment of a magnetic detector according to the invention.

Fig. 4 and 5 illustrate the magnetic head and the container, respectively, of the detector of fig. 3.

Fig. 6 is a cross-sectional view of the magnetic detector of fig. 3.

Fig. 7 shows an example of an implementation of a radially magnetized magnet with the magnetic detector of fig. 3.

Fig. 8, 9 are side and cross-sectional views, respectively, of the magnet of fig. 7, showing magnetic field lines.

FIGS. 10 to 14 show a magnetic head fixing device and a magnetic head fixing device locking device on a container.

Fig. 15 shows details of the locking device.

Fig. 16a shows an example of an implementation of the electrode.

Fig. 16b shows an embodiment of the inter-electrode insulator.

FIG. 17 shows another embodiment of a magnetic head according to the second embodiment;

FIG. 18 is a cross-sectional view of the magnetic head of FIG. 17.

FIG. 19 is an enlarged cross-sectional view of the magnetic detector of FIG. 17 showing electrical connectivity paths.

FIG. 20 shows another embodiment of a magnetic head according to the present invention.

FIG. 21 is a side view of a magnetic detector having the magnetic head of FIG. 20.

Fig. 22 is a cross-sectional view of the container of the magnetic detector of fig. 21.

FIG. 23 is a cross-sectional view of the detector of FIG. 21 showing electrical connectivity paths in the magnetic head and the can.

FIG. 24 is a perspective view of the magnetic detector of FIG. 21 with metal particles present.

FIG. 25 is a side view of a magnetic detector according to another embodiment.

FIG. 26 shows the head of the detector of FIG. 25.

FIG. 27 is a detailed view of the head end of FIG. 26 showing the structure of the magnets and electrodes.

FIG. 28 is an axial cross-sectional view of the magnetic head of FIG. 27.

FIGS. 29 and 30 show the electrode structure of the magnetic head of FIG. 27.

FIG. 31 shows the end of the magnetic head of FIG. 27 in which metal particles P are present.

Detailed Description

Referring first to fig. 3 to 15 and 16a and 16b, a first embodiment of a metal particle magnetic detector and corresponding magnetic head according to a first embodiment is shown.

In a designed embodiment, the magnetic detector is intended to be installed in a fuel tank of an aircraft generator system. However, the present invention is not limited to this application and generally encompasses the detection of metal particles within a liquid in a hydraulic circuit.

Referring first to fig. 3 to 5, a magnetic detector, generally designated by the general reference numeral 10, generally comprises a magnetic head 11 mounted in a receptacle 12. As shown, the assembly is mounted on the housing by means of a flange 13 provided on the container, which cooperates with a nut system provided on the housing. Of course, other fastening means, such as bolts, may be used instead. The magnetic detector may also be mounted on the housing by means of a screw thread provided directly on the outer peripheral surface of the container.

The magnetic head 11 comprises a generally cylindrical axial body 14 in which are mounted one or more radially magnetised magnets 15 and 16 and one or more corresponding electrodes 17 and 18. In the embodiment shown in fig. 1 to 15 and 16a and 16b, the magnetic head has a distal electrode 18 and a proximal electrode 17 extending mainly in the axial body 14.

Referring to fig. 7 to 9, the magnetic head comprises two radially magnetised cylindrical magnets, arranged end to end, in extension of each other, axially spaced apart and such that the N pole of one of the magnets faces the opposite pole S of the other magnet.

This arrangement of radially magnetized magnets enables a magnetic field to be generated in the gap between the two magnets, where the magnetic field lines guide the particle alignment, which is advantageous for improved detection. The radial orientation/alignment of the magnetization enables an optimized capture and the opposite placement of the two magnets enables an improved detection of particles located in the gap between the two magnets.

The magnet is substantially circular in cross-section and is fixed between the electrodes 17 and 18. The first proximal electrode 17 includes a base 19 fixed to the head body by a threaded fastener and a cylindrical sheath 20 surrounding the first magnet 15.

The second distal electrode 18 also has a base 21 and a cylindrical extension extending from the base. It comprises an axial stem 22 for fixing to the body of the head by means of threaded fasteners.

The proximal end of each electrode is provided with means for electrical connection to an aircraft computer. As shown, these electrical connection means may be constituted by terminals C inserted in threaded holes T (fig. 16a) provided in the axial stem 22 and the proximal electrode 17.

The container 12 comprises a cylindrical body 23 in which the magnetic head is housed, an end cap 24 and a spring 27, the end cap 24 comprising a valve 25 fixed to the end cap 24, for example by a crimp 26, the valve being normally closed but capable of opening under the action of the magnetic head when the latter is fully inserted in the container, the spring 27 being arranged between the end cap 24 and the container.

Referring to fig. 10 to 15, the detector is further provided with a fixing means for fixing the detection head in the container and a locking means for locking the fixing means.

The fixing means for fixing the magnetic head in the case includes a snap fixing means. Correspondingly, the magnetic head comprises at least two radial pins 28, which are fitted in at least 2L-shaped positioning grooves 29, respectively, which are provided on the container.

The locking means is constituted by a locking ring 30 rotatably mounted on the magnetic head and comprising at least two projections 31, said projections 31 being fitted in at least two corresponding fixing grooves 32 provided on the container.

The locking ring retains the protrusion 31 in the recess 32 under the action of the spring 33, thereby preventing rotation of the head relative to the container.

Thus, in order to unlock the head, avoiding any inadvertent disengagement of the head, it is necessary to first release the locking ring 30 by pulling the locking ring 30 upwardly against the force exerted by the spring 33, and then rotate the head until it can be removed from the container.

So arranged, as well as avoiding any erroneous mounting of the head in the container, the resetting of the locking ring under the action of the spring 33 can guide the operator: the magnetic head is correctly mounted in the container.

Referring to fig. 16a and 16b, in which the relatively bright zone Z1 represents the conductive zone and the relatively dark zone Z2 is the insulating zone, the head comprises two electrodes 17 and 18 in-line, as previously described. The electrodes are made of a conductive material covered with an insulator. The conductive zone Z1 is particularly located facing the gap zone.

For example, the electrode is made of aluminium and is covered with an insulating layer formed by a sulphuric acid hard anodisation process, forming an insulating coating, for example between 30 and 50 microns thick, and certain areas of the electrode are subsequently re-finished (or left in the coating process) and then treated by a chemical conversion of the aluminium surface chemical treatment type, to ensure electrical connectivity.

Of course, it would not depart from the scope of the invention when the electrodes are made of another material or covered with an insulating layer of another nature.

For example, as a variant of this embodiment, it is possible to cover the electrodes with an insulating material and to manufacture the conductive areas by local machining, or to partially coat the electrodes with a varnish before covering the insulating material, these varnish layers being subsequently removed to leave the exposed areas as conductive areas.

The conductive zone Z1 of the electrode is arranged in the gap zone and in the electrical connection zone of the electrode at the location of the fixing screw.

As shown in fig. 16B, the gap here comprises an insulating ring B, for example made of plastic.

In the embodiment described above, the magnetic head includes two radially magnetized magnets disposed in the direction extending from each other.

As a modification of the present embodiment, the magnetic head may also have a single cylindrical magnet, which also constitutes one of the poles of the magnetic head, as shown in fig. 17 to 20.

In this case, the magnet denoted by reference numeral 35 is a conductive magnet. It is covered with a layer of nickel, for example.

The second electrode 36 is constituted by a further cylindrical member which surrounds the magnet and comprises a set of notches 37 bounded by an electrically conductive material. These notches comprise circumferential edges, in particular conductive circumferential side edges facing each other.

In this embodiment, the second electrode 36 may be retained on the head by a gasket seal 39.

Therefore, only the magnet constituting one of the electrodes is fixed to the main body of the magnetic head by the screw fastener.

Although the embodiments described with reference to fig. 3 to 15 are advantageous in that the magnet is protected by a housing formed by two electrodes in the extension direction of each other, the present embodiment is advantageous in this respect because one electrode is omitted, increasing the volume of the magnet.

Referring to fig. 19, electrical connection inside the head is achieved by a center screw fixing the magnet (the magnet itself is electrically conductive), and electrical connection is achieved on the other side of the gap by the second electrode 36, an electrical connection spring 40, and a conductive cylinder assembly 41 interposed between the magnet and the head body.

When metal particles are present in the gap between the magnet and the second electrode, an electrical circuit enabling current to flow from the conductive region to the magnetic head, the circuit is closed, or in all cases its resistance is reduced.

In this embodiment, the magnet has a large volume, as described above. The embodiment is also simple in structure and easy to assemble.

In addition, the second electrode 36 has a plurality of gaps, each gap being located between the magnet and the slot 37, which increases the number of metal particle detection zones.

Although in the embodiment described, there is only one magnetic head, a plurality of magnets may be used as a modification of the present embodiment.

Finally, it should be noted that, as shown in fig. 18, the second electrode 36 comprises, in its end zone, an electrically insulating annular edge 42 partially covering the end of the magnet, whereby, in the absence of the removable electrode 36, for example in the event of a omission during the reassembly process, an electrical connection occurs between the magnet and the container, indicating the presence of an assembly defect.

In a second embodiment described with reference to fig. 17 to 22, the magnetic head comprises two electrodes, one constituted by a magnet and the other by an attached electrode 36, which attached electrode 36 is mounted on the body of the magnetic head by means of a mount, for example a sealing gasket 39.

In another embodiment, shown in fig. 20 to 23, from which it is known that the magnetic head 11 is provided with an axial body 14 formed substantially cylindrically and equipped with snap-in fixing means and a locking ring 30, and from which it is also known that the radially magnetized magnet 35 constitutes one pole of the magnetic head, in this embodiment the second pole is formed in the container 12.

The end cap 24 of the container, which is mounted in sliding manner with respect to the body 14 under the action of the spring 27, is provided here with a series of notches, for example 45, whose longitudinal edges are electrically conductive, for example by machining after deposition of an insulating coating.

This embodiment is advantageous because the second electrode is replaced by the container end cap 24 and therefore the volume of the magnet can be increased.

As shown in fig. 23, in this embodiment, the electrical connection path passes axially within the container body and along the conductive coating of the magnet on the one hand, and along the lid 24, the cylindrical assembly portion 40, and then to the internal terminal 46 on the other hand.

When the metal particles P are located between the magnet and the head cap, the electrical connectivity circuit is closed or its resistance is reduced.

As with the previous embodiment, this embodiment may increase the diameter of the magnet, thereby increasing its volume.

The main body portion of the head is cylindrical to facilitate visual analysis for particle removal during maintenance operations.

This embodiment also has a plurality of gaps, increasing the number of detection zones.

In this embodiment, the magnetic head is a single magnet, and in a variation of this embodiment, two welded cylindrical magnets may also be used to gather the particles.

Fig. 25 to 31 show a fourth embodiment of a magnetic head and a magnetic detector.

This embodiment differs from the embodiment described above with reference to fig. 20 to 24 in that the magnetic head comprises a plurality of radially magnetized magnets.

The electrodes, e.g. 48 and 49, are angularly distributed around the magnet, with an insulating coating, e.g. of elastomer, plastic or resin, interposed, which coating extends between the electrodes and the magnet on the one hand and the electrodes on the other hand.

The electrodes 48 and 49 are each made in one piece and comprise, for the electrodes 48 and 49, a seat 55 from which a set of teeth 51 extends. As shown in fig. 29 and 30, the electrodes 48 are mounted in a coaxial manner in the other electrode 49 such that the teeth of one electrode are inserted between two teeth of the other electrode, respectively, and then overmolded together.

In this embodiment, the electrical connection loop is closed when the magnetic particle P is located between two sequential electrodes 48 and 49, as shown in fig. 31.

As mentioned above, each electrode is made, for example, of aluminum covered with a coating which serves as protection against corrosion and ensures electrical insulation. The coating is formed, for example, by a sulfuric acid hard anodizing process, and portions of the electrode are machined to remove the coating and expose the aluminum. The components are then assembled. Then, elastomer overmolding is performed.

Of course, other processes such as resin coating and the like may be used without departing from the scope of the invention. Machining may then be performed to locally remove the insulating coating and obtain a conductive area on each electrode.

In the embodiments that have been described, it is preferred that the magnet is a neodymium magnet. For example, 45SH type neodymium iron boron may be considered, which is resistant to high temperatures (e.g., 150 ℃) while exhibiting strong power.