FR3035766B1 - INDUCTION HEATING DEVICE FOR METALLIC PARTS AND RAILWAY VEHICLE COMPRISING SUCH A DEVICE - Google Patents

Abstract

The invention relates to a device (100) for the induction heating of a metal part (102), in particular of an elongated metal part, characterized in that it comprises: at least one magnetic core (104) ) open, intended to be disposed opposite said part to be heated, and - at least one induction coil (106), wound around at least a part of said at least one magnetic core (104), to induce a magnetic field in said magnetic core (104); said magnetic core (104) having a general shape bent toward said metal piece (102). It also relates to a railway vehicle equipped with such a device.

Description

"Induction heating device for metal parts and railway vehicle comprising such a device"

The present invention relates to a heating device by induction of a metal part, in particular of an elongated metal part. It also relates to a railway vehicle equipped with such a device.

The field of the invention is the field of induction heating of metal parts, in particular elongated metal parts, for example in the railway field.

State of the art

Induction heating makes it possible to heat a metal part without any contact between the energy source and the part to be heated.

Induction heating devices include an electrical source supplying one or more induction coils for inducing eddy currents in a metal piece near said one or more coils. These eddy currents cause a heating of the metal part by Joule effect. In these devices, the use of a ferrite plate and / or a magnetic core makes it possible to increase the efficiency of these devices by acting on the magnetic field lines.

To heat an elongated metal piece of the metal bar type, a first solution is to use a magnetic excitation coil which encircles the piece. However, this solution is not usable in all cases because it is not always possible to encircle the part to be heated. In addition, when the part is very long, it is necessary to provide a coil having a large number of turns which increases the size, weight and impedance of the coil, and decreases the heating efficiency. When the part to be heated is fixed on a vehicle, or more generally on a mobile, these disadvantages are even more restrictive.

Another solution is to use a flat coil, arranged opposite the workpiece, and which does not impose encircling the workpiece to be heated. However, this second solution has a very low efficiency because the heating zone obtained with such a coil on an elongated piece is too small, even punctual, even increasing the diameter of the flat coil. In addition, the heating zone is small, the room to be heated is not uniformly heated.

An object of the present invention is to overcome these disadvantages.

Another object of the invention is to provide a device for heating a part, in particular an elongate piece, having a better performance than known devices.

Yet another object of the invention is to provide a device for heating a workpiece, in particular an elongated workpiece, for a more uniform heating of the workpiece to be heated.

It is yet another object of the invention to provide a device for heating a room, in particular an elongated piece, less expensive and less bulky.

Finally, another object of the invention is to provide a device for heating a room, in particular a piece of elongated shape, more flexible and more ergonomic regardless of the configuration and size of the room to be heated.

DISCLOSURE OF THE INVENTION The invention makes it possible to achieve at least one of these objects by means of a device for induction heating of a metal part, in particular of an elongated metal part, said device comprising: at least one open magnetic core, and in particular a magnetic core comprising at least two ends, arranged to be disposed opposite said part to be heated, and - at least one induction coil, wound around at least a part of said at least one magnetic core for inducing a magnetic field in said magnetic core; said magnetic core having a general shape curved towards said metal part.

Thus, the magnetic core curved towards the part to be heated directs the magnetic field towards the metal part to be heated. In other words, the metal part to be heated is located in the magnetic core. The metal piece somehow closes the magnetic circuit between the ends of the magnetic core.

Thus, the magnetic field created in the magnetic core, travels and passes through the magnetic piece between the ends of the open magnetic core. This magnetic field traversing the metal part creates eddy currents that heat the metal part.

The device according to the invention thus makes it possible to direct all, or almost all, of the magnetic field created by the induction coil to the part to be heated. Therefore, the induction heating efficiency obtained with the device according to the invention is greater than the yields obtained with the known devices, and with an induction coil of smaller dimensions and lower cost than the coils used in the known devices.

Furthermore, the heating zone obtained with the device according to the invention is at least as large as the distance separating the two ends of the magnetic core. Consequently, the device according to the invention makes it possible to achieve more uniform heating than known devices using flat coils.

In addition, unlike some devices of the state of the art, the device according to the invention does not require to encircle the metal part to be heated by the induction coil. Therefore, the device according to the invention is more flexible and more ergonomic regardless of the configuration and the size of the part to be heated, whether embedded or not in a mobile.

The magnetic core can be made in no way limiting, for example soft ferrite.

The device according to the invention may further comprise at least one electrical source supplying the at least one induction coil.

Alternatively, the at least one induction coil may be powered by a source of a rail vehicle, more generally a mobile, equipped with the device according to the invention.

According to the invention, each induction coil can be powered by an independent electrical source.

Alternatively, at least two, in particular all, induction coils wound around a magnetic core can be powered by the same electrical source part or not of the device according to the invention. In this case, the induction coils fed by the same source can be connected to said source in series or in parallel.

In any case, it is of course necessary to ensure that each coil is powered so that all the magnetic coils induce a magnetic field whose direction of flow in the magnetic core is the same.

Advantageously, at least one, in particular each, magnetic core may comprise at least two, in particular exactly two, branches forming between them an angle less than 180 °.

When a magnetic core has exactly two branches forming between them an angle less than 180, the magnetic core has a general shape in "V".

In this case, in the configuration of use, the magnetic core is positioned so that the branches are directed towards the metal part to be heated. This embodiment has the advantage of a simple architecture for the magnetic core and using less magnetic material.

In the case where at least one magnetic core comprises at least two or exactly two branches, the device according to the invention may comprise at least two, in particular exactly two, induction coils each: - wound around one of the branches of the magnetic core, and - fed so as to generate a magnetic flux flowing in the same direction in said magnetic core.

At least one, in particular each, magnetic core may comprise at least three, in particular exactly three, branches.

In this case, two of said branches, said side branches, may be substantially parallel to each other and connected to each other by at least one, in particular exactly one, branch, said central branch.

When a magnetic core has exactly three branches, the magnetic core has a general "U" shape.

In this case, the device according to the invention may comprise an induction coil wound around the central branch.

Alternatively, or in addition, the device according to the invention may comprise an induction coil wound around one or each of the lateral branches.

Whatever the embodiment, when the device comprises several coils.

According to another embodiment, the core may be formed by a single curved branch, or in a circular arc, for example in the shape of a "C". In this case, the device according to the invention may comprise one or more induction coils arranged around said single branch.

Whatever the embodiment, at least one, in particular each, magnetic core may have a parallelepipedal or circular, triangular, and so on.

Whatever the embodiment, at least one, in particular each, magnetic core may have a section whose largest dimension is between 5 cm and 15 cm, preferably between 8 and 12 cm, and even more particularly is 10 cm.

According to a particular version, the device according to the invention may comprise a plurality of magnetic cores each comprising at least one induction coil wound around at least a portion of said magnetic core.

More particularly, at least one, in particular each, magnetic core may have at least one of the features described above.

At least two, in particular all, magnetic cores may be of shape and / or of section and / or of the same or different dimensions.

Whatever the embodiment, when the device comprises several induction coils, at least two, in particular all the induction coils, of the same magnetic core may be of shape and / or of section and / or of identical or different dimensions.

When the device according to the invention comprises at least two identical or different cores, the induction coils of at least two, in particular of all, magnetic cores may be of identical shape and / or section and / or dimensions (s) or different.

The device according to the invention may comprise a single electrical source supplying the or each induction coil of the same core with an alternating electric current.

When the device according to the invention comprises several magnetic cores, the induction coil or coils of at least two, in particular of all, magnetic cores can be powered by a single electrical source.

In this case, the induction coils of the same magnetic core or two magnetic cores can be connected to the electrical source in series or in parallel.

Alternatively, the device according to the invention may comprise at least two electrical sources so that at least two of said induction coils of the same magnetic core, or two magnetic cores, are powered by two different electrical sources.

The device according to the invention can be used to heat railway switches and rails, or to heat any elongate metal part of a railway vehicle.

According to another aspect of the invention there is provided a railway vehicle, such as a train or a tram or a tram-train, provided with an induction heating device according to the invention.

DESCRIPTION OF THE FIGURES AND EMBODIMENTS Other advantages and features will appear on examining the detailed description of a non-limiting embodiment, and the accompanying drawings in which FIG. 1 is a schematic representation of a first example. embodiment of a device according to the invention; - FIGURE 2 is a schematic representation of a second embodiment of a device according to the invention; FIG. 3 is a schematic representation of a third exemplary embodiment of a device according to the invention; FIGURE 4 is a schematic representation of a fourth embodiment of a device according to the invention; and FIGURES 5a-5d are schematic representations of magnetic cores of different shapes that can be used in the device according to the invention.

It is understood that the embodiments which will be described in the following are in no way limiting. In particular, it will be possible to imagine variants of the invention comprising only a selection of characteristics described subsequently isolated from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from the state of the prior art. This selection comprises at least one preferably functional characteristic without structural details, or with only a part of the structural details if this part is only sufficient to confer a technical advantage or to differentiate the invention from the state of the prior art.

In the figures, the elements common to several figures retain the same reference.

FIGURE 1 is a schematic representation of a first embodiment of an inductive heating device of a metal part.

The device 100 shown in FIG. 1 is intended to heat a metal piece 102, of elongate shape, that is to say a metal piece whose dimension in one dimension of space is much larger than its dimensions in both other dimensions of the space.

The device 100 comprises a magnetic core 104, for example made of soft ferrite, an induction coil 106 wound around the magnetic core and an electrical source 108 supplying the induction coil 106 with an alternating current.

In the example shown in FIG. 1, the magnetic core 104 has a general "U" shape and a rectangular section. The magnetic core 104 in the form of "U" comprises: two lateral branches 104 1 and 10 42, corresponding to the lateral branches of the "U", substantially parallel to one another, and directed towards the metal part 102 to be heated 102; and - a central branch 1043, corresponding to the base of the "U", and joining together the parallel branches 104i and 1042.

The induction coil 106 consists of a magnetic excitation coil and is wound around the central branch 1043. The free space between the free ends of the side branches 104 1 and 10 42 constitutes the air gap of the magnetic core 104.

The part to be heated 102 is positioned facing the free ends of the side branches 104i and 1042 in contact or not with the side branches 104i and 1042.

The induction coil 106 creates a magnetic field flowing in the magnetic core 104 so that magnetic field lines 110 are created at the gap of the magnetic core 104, that is to say between the ends. free of lateral branches 104i and 1042. The part to be heated being disposed facing the magnetic core 104 at its air gap, the magnetic field lines 110 which are created induce eddy currents in the room to be heated 102. Foucault currents then heat the room 102, by dissipation according to the law of Joule. The heating zone thus obtained, embodied by the dashed circle referenced 112, extends over substantially the entire length of the gap of the magnetic core, that is to say over the entire distance which separates the free ends of the lateral branches. 104i and 1042 of the magnetic core 104.

Of course, the induction coil 106 may also be wound around one of the lateral branches 104i and 1042 of the magnetic core 104.

FIG. 2 is a schematic representation of a second example of an induction heating device according to the invention.

The device 200 shown in FIGURE 2 comprises the same magnetic core 104 as that of the device 100 of FIGURE 1. Unlike the device 100 of FIGURE 1, the device 200 of FIGURE 2 comprises not one but two coils. 202i and 2022 respectively, each wound around a lateral branch, respectively 104i and 1042, of the magnetic core 104.

Each induction coil, respectively 202i and 2022, is supplied by an independent electric source, respectively 204i and 2042, so as to generate a magnetic field propagating in the magnetic core 104 in the same direction, that is to say in the direction from the side branch 104i to the metal part 102 for the coil 202i and in the direction from the side branch 1042 to the central branch 1043.

FIGURE 3 is a schematic representation of a third example of an induction heating device according to the invention.

The device 300 shown in FIG. 3 corresponds to the device 200 of FIG. 2, except that the device 300 comprises a single electrical source supplying the two induction coils 202i and 2022 wound around the lateral branches, respectively 104i and 1042, of the magnetic core 104. The induction coils 202i and 2022 are each connected to the single source in parallel.

Of course, the induction coils 202i and 2022 may alternatively be connected to the single source in series.

In FIGURES 2 and 3, each of the induction coils is wound around a lateral branch of the magnetic core. Of course, one of the induction coils can alternately be wound to the central branch of the magnetic core.

More generally, the magnetic core 104 may comprise one to three induction coils wound on one or three of its branches, supplied in series or in parallel by one to three electrical sources.

FIGURE 4 is a schematic representation of a fourth example of an induction heating device according to the invention.

The device 400 of FIGURE 4 is made by using, adjacent, two magnetic cores 104i and 1042, each of which corresponds to the magnetic core 104 of FIGURES 2 or 3 and which each generate a heating zone in the part to be heated, respectively 112i and 1122.

The device 400 comprises a single electrical source 402, to which are connected in series the four induction coils 202i and 2022 of the two cores 104i and 1042, and feeding the four induction coils.

Of course, at least two induction coils of the device 400 may alternatively be connected in parallel. In addition, the induction coils of the device 400 may alternatively be powered by at least two electrical sources. In particular, the device 400 may comprise an electrical source supplying each induction coil independently, or the induction coils of each magnetic core independently.

Alternatively, the device 400 may comprise more than two magnetic cores. Each magnetic core may be equipped with one, two or three induction coils as described above.

In addition, the magnetic core can have different shapes, sections and / or dimensions.

FIGURES 5a-5d are schematic representations of magnetic cores of different shapes that can be used in the device according to the invention, and in particular in the devices of FIGURES 1 to 4.

FIGURE 5a shows a magnetic core 502 having a generally "U" shape with rounded corners.

FIGURE 5b shows a magnetic core 504 whose shape corresponds to a semicircle.

FIGURE 5c shows a magnetic core 506 whose shape corresponds to a "V".

FIGURE 5d shows a magnetic core 508 whose shape corresponds to a trident.

Each of the magnetic cores shown in FIGURES 5a-5d may be provided with one or more induction coils. A device according to the invention may comprise one or more magnetic cores represented in FIGS. 1 to 5 d which are identical or different.

Of course, the invention is not limited to the examples detailed above.

Claims (9)

A railway vehicle provided with an induction heating device (100-400) for inductively heating an elongate metal part (102), such as rail switches or rails, characterized in that said device heating device comprises: - at least one open magnetic core (104), intended to be arranged in front of said part to be heated, and - at least one induction coil (106; 2021-2022), wound around at least a portion of said at least one magnetic core (104) for inducing a magnetic field in said magnetic core (104); said magnetic core (104) having a general shape bent toward said metal piece (102). 2. Vehicle according to claim 1, characterized in that at least one magnetic core (104) comprises at least two branches (1041-1043) forming between them an angle of less than 180 °. 3. Vehicle according to the preceding claim, characterized in that the heating device (200-400) comprises at least two induction coils (2021,202) each: - wrapped around one of the branches (1041, 1042) of the magnetic core (104), and - energized so as to generate a magnetic flux flowing in the same direction in said magnetic core (104). 4. Vehicle according to any one of the preceding claims, characterized in that at least one magnetic core (104) comprises two branches (1041-1042), said side, substantially parallel to each other, and at least one branch (1043 ), said central, connecting said lateral branches (1041-1042) between them. 5. Vehicle according to the preceding claim, characterized in that the heating device (100-400) comprises a coil (106) wound around the central branch (1043), and / or an induction coil (202i-2022). wrapped around one or each side branches (104i, 1042). 6. Vehicle according to any one of the preceding claims, characterized in that at least one, in particular each, magnetic core (104) has a section whose largest dimension is between 5cm and 15cm, preferably is 10cm. 7. Vehicle according to any one of the preceding claims, characterized in that the heating device (400) comprises a plurality of magnetic cores (1041, 1042) each comprising at least one induction coil (2021, 2022) wound around at least a portion of said magnetic core (1041, 1042). 8. Vehicle according to any one of the preceding claims, characterized in that the heating device (100; 300; 400) comprises a single electrical source (108; 302; 402) supplying the or each induction coil (106; 202i, 2022) by an alternating electric current. 9. Vehicle according to any one of claims 1 to 7, characterized in that the heating device (200) comprises at least two electrical sources (204i, 2042) so that at least two induction coils (202i, 2022) ) of the same magnetic core (104), or two different magnetic cores, are fed by two different electrical sources (204i, 2042).