EP3520214A1

EP3520214A1 - Generator for transforming a translational movement of a body into an accumulation of electric charges

Info

Publication number: EP3520214A1
Application number: EP17783924.8A
Authority: EP
Inventors: Jérôme Delamare; Thibault RICART; Jérémy LAVILLE; Stéphane VIMPIERRE
Original assignee: Enerbee SAS
Current assignee: Enerbee SAS
Priority date: 2016-09-27
Filing date: 2017-09-20
Publication date: 2019-08-07
Also published as: WO2018060568A1; US20190253002A1; FR3056854A1; FR3056854B1; JP2019535227A; CN109863679A

Abstract

The invention relates to a generator (1) for transforming a translational movement of a push element (5) into an accumulation of electric charges, comprising a converter (2) capable of transforming a magnetic field variation into a charge accumulation; a magnetic field source (3) defining a housing (4) in which a magnetic field prevails; the push element (5) being movable from a first position to a second position along a translational direction. According to a first aspect, the invention comprises a transmission device for transmitting the movement of the push element (5) into a rotational movement of the field source (3) or of the converter (2) in order to vary the magnetic field in the reference plane of the converter. According to another aspect, the invention involves moving the push element from a first position in which the converter (2) is subject to a first field configuration, to a second position in which the converter (2) is subject to a second field configuration, different from the first.

Description

GENERATOR FOR TRANSFORMING MOTION OF BODY TRANSLATION IN ACCUMULATION OF ELECTRICAL LOADS

FIELD OF THE INVENTION

The invention relates to a generator adapted to transform the translational movement of a body into an accumulation of electric charges.

BACKGROUND OF THE INVENTION

The document "Magnetostricitve-Piezoelectrie composite structure for energy harvesting", Journal of micromechanics microengineering No. 22, 2012 by T. Lafont et al, discloses such a generator which comprises:

A converter capable of transforming a magnetic field variation into an accumulation of electric charges. The converter consists of a layer of magnetostrictive material assembled on each of its faces to a layer of a material having piezoelectric properties.

- A magnetic field source, in the form of a permanent magnet.

The translation displacement of the magnetic field source in a plane parallel to and overhanging the converter leads to the accumulation of charges in the converter. These charges can then be removed for storage and / or to supply energy to a circuit.

US6984902 discloses a vibration energy recovery device of a body also implementing a converter and a field source.

However, for a given level of accumulated charges, the known devices are relatively bulky or inefficient, which makes them incompatible with certain targeted applications. This is particularly the case when one seeks to recover the energy of a small pusher element of a more complex device, when this pusher element is actuated by a user (switch, actuating button, etc.) . In this type of application, it is important to be able to recover a maximum of loads, even when the movement is of low amplitude (from a few mm to a few cm) and of low speed (from 0.01 to less than lm / s) . OBJECT OF THE INVENTION

An object of the invention is therefore to provide a generator capable of transforming the translational movement of a pusher element into a charge accumulation, efficient and compact.

BRIEF DESCRIPTION OF THE INVENTION

In order to achieve this object, and according to a first aspect, the object of the invention proposes a generator for transforming a translational movement of a pusher element into an accumulation of electric charges comprising:

a converter comprising a reference plane and capable of transforming a magnetic field variation in the reference plane into a charge accumulation;

a source of magnetic field defining a housing in which a magnetic field prevails;

the pusher element, integral with the source or the converter, being movable in a direction of translation perpendicular to the reference plane of a first position in which the converter is placed in the housing at a first plane and subjected to a first field configuration in its reference plane, to a second position in which the converter is subjected to a second field configuration in its reference plane, different from the first.

By placing the converter in the housing of the field source, a compact generator is formed. And the displacement of the pusher element causes the variation of the magnetic field to which the converter of a first configuration is subjected, a second configuration leading to the generation of the electric charges.

According to other advantageous and non-limiting features of the invention, considered individually or in any technically possible combination:

The converter is formed of a layer made of a magnetostrictive material defining the reference plane, connected to at least one layer made of a piezoelectric material;

• The generator comprises return means of the pusher element in the first or second position;

• In the second position, the converter is placed out of the housing and in which the second field configuration corresponds to a field peripheral to the magnetic field source;

The magnetic field source comprises an assembly of magnets forming a Halbach cylinder and the first field configuration is a uniform field in the housing;

In the second position, the peripheral field is perpendicular to the reference plane and issuing from a peripheral magnetic field source;

In the second position of the pusher element, the converter is placed in the housing at a second plane;

The field source comprises a stack formed of a first Halback cylinder generating the first field pattern in the first plane, and a second Halback cylinder generating the second field pattern in the second plane; The field source comprises a first magnetically permeable element and a second magnetically permeable element configured to orient the magnetic field on the converter according to the first field configuration when the pusher element is in the first position and in the second configuration when the push element is in the second position; · The first field pattern and the second field pattern correspond to uniform fields forming an angle of 90 ° with each other.

According to a second aspect, the object of the invention proposes a generator for transforming a translation movement of a pusher element displaceable from a first position to a second position, in a direction of translation, into an accumulation of electric charges, the generator comprising:

a converter comprising a reference plane and capable of transforming a magnetic field variation in this reference plane into an accumulation of charges, the converter being arranged in the housing so as to place at least a part of the field in the plane; reference ;

a device for transmitting the displacement of the pusher element in a rotation movement of axis perpendicular to the reference plane of the field source or of the converter, for varying the magnetic field in the reference plane of the converter.

By placing the converter in the housing of the field source, a compact generator is formed. And the displacement of the pusher element is transmitted in a rotational movement varying the magnetic field vis-à-vis the converter, which leads to the generation of electric charges in it.

The transmission device comprises a multiplier gear; The transmission device is configured so that the displacement of the pusher element from the first position to the second position causes the rotation of the magnetic field in the reference plane by an angle greater than or equal to 90 °; The generator comprises means for returning the pusher element in the first position;

The magnetic field source is a magnet assembly forming a Halbach cylinder generating a uniform field in the housing;

• the translation direction is parallel to the reference plane; · The transmission device comprises a rack integral with the pusher element cooperating with a toothed wheel integral with the source or the converter;

• the translation direction is perpendicular to the reference plane; the transmission device comprises a threaded rod secured to the pusher element cooperating with a nut that is only free to rotate; • the transmission device comprises a transmission belt and at least two rollers.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood in the light of the following description of the particular and nonlimiting embodiments of the invention with reference to the attached figures among which:

FIGS. 1a and 1b schematically represent two views of generators that are compatible with the invention.

FIGS. 1a and 1d respectively represent a section and a view from above of an electromagnetic converter compatible with an electric generator according to the invention;

FIG. 2 is a graphical representation of the quantity of charges generated by the converter as a function of the angle Θ existing between the direction of the magnetic field and the direction of polarization of the piezoelectric layers;

FIGS. 3a to 3c represent different possible configurations of a magnetic field source of the electric generator according to the invention;

FIGS. 4a to 4c represent different views of a first exemplary implementation of the invention according to a first embodiment;

Figure 5 shows a gear train;

FIG. 6 diagrammatically represents a second exemplary implementation of the invention according to its first embodiment;

FIG. 7 diagrammatically represents a third example of implementation of the invention according to its first embodiment;

- Figure 8 schematically shows a fourth example of implementation of the invention according to its first embodiment; Figures 9a and 9b show schematically a first example of implementation of the invention according to a second embodiment;

Figures 10a and 10b show an alternative to the first example of Figures 9a and 9b;

Figures 11a and 11b schematically show a second example of implementation of the invention according to its second embodiment;

Figures 12a, 12b and 12c schematically show a third example of implementation of the invention according to its second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an electric generator

I capable of transforming the translational movement of a body, even of small amplitude (from a few mm to a few cm) and of low speed (from 0.01 to less than 1 m / s), in a generation and a charge accumulation electric.

Elements common to all embodiments

FIGS. 1a and 1b show diagrammatically two exemplary embodiments of such a generator 1. In an optional box 1a, the generator comprises a pusher element 5 connected to a converter 2. The converter is electrically connected to two terminals 1b which can be integrated in the case, for its electrical connection with an associated device.

The pusher element 5 is movable in a translation direction, from a first position to a second position.

It may be for example a push button directly or indirectly operable in translation by a user. This translational movement can take different forms, for example in a direction perpendicular to a main surface of the case la as shown in FIG. la, or in a direction in the plane of the box la as shown in Figure lb.

The pusher element 5 may be included in a part of a more complex mechanical device, such as a switch, leading to the displacement in translation of the pusher element 5, when this complex mechanical device is actuated by the user. As represented by way of example in FIGS. 3a to 3c, the generator 1 according to the invention also comprises a magnetoelectric converter 2 and a magnetic field source 3, such as a permanent magnet. The converter 2 and the source 3 can move relative to each other. The source 3 defines a housing 4 in which the converter 2 can be placed and form a particularly compact assembly. The energy resulting from the translational movement of the pusher element 5 will be partly recovered by the assembly formed of the converter 2 and the magnetic field source 3, and transformed into electric charges. These charges are collected, and possibly stored by means of a control device associated with the generator 1 (which can be connected to the terminals lb). They can be used, for example, to supply and enable the operation of an electrical or electronic device such as a signal transmitter connected to the generator 1. As additional examples, they can also be used for recharging a battery, or to supply a sensor or an array of environmental data sensors (temperature, humidity, etc.). Such a control device is known for example from WO2014063958, WO2014063952, WO2014063951 or WO2007063194 and will not be described here in more detail.

Figures 1a and 1d show a particular example of a magneto-electric converter 2 compatible with an electric generator 1 according to the invention. The converter 2 is able to transform the variation of a magnetic field in a reference plane into a charge accumulation. The converter 2 comprises a layer 20 of magnetostrictive material preferably having a magnetostriction coefficient, in absolute value and at saturation, greater than 10 ppm, or even 100 or 1000 ppm. It is recalled that this coefficient is defined by the quotient AL / L where AL is the elongation of the material in the presence of a magnetic field saturating the material, and L the length of this material in the absence of a magnetic field. Preferably, the material of the layer 20 is chosen to be intrinsically isotropic or to exhibit isotropic behavior in the generator 1, as is the case when an anisotropic material is subjected to a field of sufficient intensity to saturate it magnetically. It may for example be formed of a block of Terfenol D, FeSiB, or a FeCo alloy.

As can be seen in FIG. 1d, in the top view of the converter 2, the layer 20 may have a disk shape. The layer 20 defines a reference plane for the converter 2 and the generator 1 in which it is placed. This form of disk allows the converter to turn on itself, or to be inserted in a rotating element, axis perpendicular to the reference plane and passing close to the center of the disk, in a restricted generated volume.

As is well known per se, the application of a magnetic field to the layer 20 in a given direction in the reference plane causes the deformation of the layer in this determined direction (an elongation when the magnetostriction coefficient of the layer 20 is greater than 0).

The magneto-electric converter 2 also comprises, integrally assembled to the layer 20, at least one piezoelectric layer 21a, having electrodes 22a. In the example shown in the Figure, two piezoelectric layers 21a, 21b are assembled on one and the other of the faces of the layer 20. Each of these layers piezo electric ^¬ 21a, 21b have electrodes 22a, 22b at least on one of their faces, for example on their free face. As can be seen in FIG. 1d with respect to the electrode 22a, the electrodes 22a, 22b may be interdigitated to effectively collect the charges from each of the layers 21a, 21b.

As the piezoelectric layers 21a, 21b are integrally joined to the magnetostrictive layer 20, the deformation of this layer 20 in the reference plane also causes the deformation of the piezoelectric layers 21a, 21b in a plane parallel to this reference plane.

The piezoelectric layers 21a, 21b are preferably biased in a direction of polarization contained in the plane that they define. When several piezoelectric layers 21a, 21b are present, they are advantageously arranged on the magnetostrictive layer 20 so that their axes of polarization are arranged parallel to each other. We will consider that this is the case in the description to come.

The deformation of the piezoelectric layers 21a, 21b according to their polarization directions causes a creation of electric charges in these layers and their accumulation on the electrodes 22a, 22b. Such deformation is obtained when the magnetostrictive layer 20 is subjected to a magnetic field whose orientation has a component parallel to the polarization direction of the layers 21a, 21b. FIG. 2 is a graphical representation of the amount of charges generated on the electrodes 22a, 22b as a function of the angle Θ between the direction of a uniform magnetic field developing in the magnetostrictive layer and the polarization direction of the layers. 21a, 21b. It is observed that, in the absence of their collections, the accumulated charges oscillate between a maximum value Q1 and a minimum value Q0. The maximum value is reached when the angle Θ is equal to 0 ° and 180 °, that is to say when the directions of the magnetic field and the axis of polarization are parallel. The minimum value QO is reached when the angle Θ equals 90 ° and 270 °, that is to say when the direction of the magnetic field and the axis of polarization are perpendicular. Between two consecutive extremes, there is therefore creation of charges (positive or negative) in the piezoelectric layers 21a, 21b.

Advantageously, when the converter 2 is subjected to a rotating magnetic field, the control circuit is configured to collect the charges created at each quarter turn, for angles Θ of 0 °, 90 °, 180 ° and 270 °, at 30 °. ° near.

In this way, a magneto- electric converter 2 is formed capable of transforming the variations, in the reference plane defined by the magnetostrictive layer, of a magnetic field into a charge accumulation at the level of the electrodes 22a, 22b of the piezoelectric layers. electric 21a, 21b.

Note that the generator according to the invention is not limited to a converter 2 of the precise form just described. Thus a converter 2 comprising a single piezoelectric layer 21a or comprising a plurality of magnetostrictive layers is fully compatible with the invention. Similarly, the electrodes 22a, 22b may take other forms or be deployed differently from what has been described in the preceding paragraphs.

The generator 1 also comprises a magnetic field source 3. The magnetic field source 3 defines a housing in which there is a magnetic field. In FIGS. 3a to 3c, this field is represented by the field lines in dashed lines. The housing 4 and the source 3 are configured so that the converter 2 can be placed in the housing so as to have at least a portion of the field in its reference plane. Source 3 and Converter 2 are free to move relative to each other, in order to create in the housing 4 a rotating field vis-à-vis the converter.

Preferably, the field prevailing in the housing 4 is uniform, that is to say that it has a direction and / or a relatively constant intensity at least in a central portion of the housing and preferably at any point of the housing. It is thus easy to place the converter in the housing 4 without the need to position it accurately in a particular place.

There are multiple ways of realizing the field source 3. According to a first approach, the source 3 is formed of a plane assembly of permanent magnets oriented relative to each other so as to confine a magnetic field on one side of this plan. This assemblage is well known as the Halbach Network.

By placing two of these assemblies face to face, the fields facing each other, the housing 4 is defined by the space separating these two planes. This configuration is represented in FIG. 3a. Note however that it is not necessary to have two planar assemblies, and a single assembly is sufficient to generate a useful magnetic field.

According to a second approach, a plurality of permanent magnets are arranged relative to each other along a closed contour to define the housing 4 and create a field inside thereof. By way of example, it may be a Halbach cylinder configuration, shown schematically in FIG. 3b. As a complementary example, it may be a closed soft iron structure, defining the housing, two permanent magnets of identical magnetic moment are placed vis-a-vis in the housing as shown in FIG. 3c. Whatever the chosen configuration of the source 3, the converter 2 is placed in the housing 4 so that at least part of the field prevailing therein is arranged in the reference plane.

Outside housing 4 there is a peripheral field which may for example correspond to the earth's magnetic field. The configuration of the peripheral field (that is to say its intensity, its direction) is different from the configuration of the field prevailing in the housing 4.

The present invention takes advantage of the various elements that have just been described in detail to form a device capable of transforming the translational movement of a body into an accumulation of electrical charges.

First embodiment In this embodiment, the magnetic field generated by the source 3 in the housing 4 can be rotated vis-à-vis the converter 2 along an axis perpendicular to the reference plane. Thus, a rotating field is formed and thus variable in the reference plane leading to the generation of charges on the electrodes 22a, 22b of the converter 2.

The rotation of the field can be obtained by rotating the converter 2 about an axis of rotation perpendicular to the reference plane and passing through its center.

Alternatively, the rotating field can be obtained by holding the converter stationary and rotating the field source 3 around the axis of rotation perpendicular to the reference plane and passing through the center of the converter 2 or in its vicinity. . This configuration, in which the converter 2 is fixed, is particularly advantageous, since it makes it possible to simply connect the control device to the converter 2. Of course, the converter 2 and the source 3 can simultaneously be rotated, insofar as they are in relative displacement with respect to each other, in order to rotate the field vis-à-vis the converter 2 .

Whichever approach is adopted, the converter 2 is held in the housing and subjected to the variable magnetic field (for example rotating) in its reference plane.

In this first embodiment of the invention, the generator 1 also comprises a device for transmitting the translational movement of the pusher element 5 in a rotational movement of the source 3 or the converter 2, with an axis perpendicular to the plane reference. In other words, the displacement of the pusher element 5 in translation from a first position to a second position leads to the displacement in rotation of the source 3 or the converter 2, preferably on itself, and along an axis perpendicular to the reference plane. As we have seen, this rotational movement leads to forming in the housing 4 of the source 3 a rotating magnetic field vis-à-vis the converter 2, and the generation and accumulation of electrical charges on the electrodes 22a, 22b of the converter 2.

Figures 4a to 4c show different views of a simple example of implementation of the invention according to this embodiment. In this example, the field source 3 is a cylinder of

Halbach generating a uniform field in at least part of the housing 4 that it defines. The heart of this cylinder defines the housing 4 in which the converter 2 can be placed. As can be seen in FIG. 4c, a circular face of the cylinder has an opening giving access to the housing 4 in order to place therein the converter 2 (not shown in this figure). On the other plane circular side of the cylinder are coaxially fixed a toothed wheel 6 and an axis 7. As can be seen on the side section of FIG. 4a, the free end of the axis 7 is supported by a wall 8 of the casing la, to maintain the cylinder 3 in position while preserving its rotational movement about the axis 7. The converter 2 is positioned in the housing, and held fixed on a second wall 8 of the box la. The rotation of the cylinder 3 makes it possible to create a rotating field in the reference plane of the converter. The toothed wheel 6 attached to the cylinder 3 cooperates with a rack 9 secured to the pusher element 5. The displacement of the pusher element 5 in translation along the main direction of the rack causes the latter to move in translation and the rotation of the cylinder 3.

The configuration of the rack 9 and the toothed wheel 6 will be chosen so that the displacement, even of small amplitude, of the pusher element 5 leads to the rotation of the magnetic field by an angle sufficient to accumulate a requisite quantity of electrical charges. . The source 3 can be moved in rotation by several turns during the translation of the pusher element 5 from its first position to its second position, or a portion of a tower, depending on the energy required for the application.

In order to facilitate this, provision can be made between the rack 9 and the toothed road 6 for a reduction mechanism or a gear train 10, a particular example of which is shown in FIG. 5. This mechanism can be fixed against a wall 8.

Advantageously, the generator 1 may be provided with a return means 11, such as a spring, for repositioning the pusher element 5 in its first position after it has reached the second position. The return movement of the pusher element 5, from the second position to the first position, can be used to continue the generation and accumulation of charges. For this accumulation to be useful, it will be ensured that the control device is able to collect the charges in this dual mode of operation. To ensure maximum load generation, especially when the rotational movement of the magnetic field is less than one turn when the pusher element is activated, it is particularly advantageous to orient the converter 2 towards the field so that in the first position, the polarization axis of the piezoelectric layer is aligned with the magnetic field prevailing in the housing 4 (or perpendicular thereto). Thus, when the pusher element 5 is positioned in its first position, the deformation of the converter in the direction of the polarization axis is extreme (maximum or minimum).

Many variations in this example of the first embodiment of the invention are possible.

Thus, the toothed wheel 6 is not necessarily placed against a circular face of the cylinder 3 as shown in Figures 4a to 4c. Alternatively, the toothed wheel 6 can be formed by providing the outer contour of the cylinder 3 with teeth that can cooperate with the rack 9 or with the teeth of a gear train 10.

In the example shown in Figures 4a to 4c, the displacement in translation of the pusher element 5 is formed in a plane parallel to the reference plane. By providing some of the gears 9, 6, 10 of conical wheels, it is possible to orient the displacement of the pusher element 5 in any angular position vis-à-vis the reference plane. It can in particular be placed in a plane perpendicular to the reference plane.

According to another variant of this first embodiment, the pusher element 5 and / or the rack 9 may be provided with an end-of-stroke locking device, having the effect of maintaining in this position the pusher element 5 a once he has reached this extreme position. The locking device can be released by applying an additional force to the pusher element, and this element can be translated by taking advantage of the recalling efforts. As previously mentioned, this return movement can also make it possible to generate and accumulate electric charges. Figure 6 schematically shows a second example of implementation of the invention according to its first embodiment. The source 3 and the converter 2 are similar configurations to that of the previous example. However, in this example, the transmission device comprises a threaded rod or a screw 15, integral with the pusher element 5.

The screw 15 is arranged in the example shown in a direction perpendicular to the reference plane. The screw 15 cooperates with a nut 12 itself secured to a toothed wheel 13 so that the translation of the screw along its longitudinal axis rotates the nut 12 and the gear wheel 13. The nut 12 is only free to move in rotation about the main axis of the screw 15. The threading of the screw 15 and the grooving of the nut 12 are chosen to allow the reversible transmission of the rotational and translational movements of each of these parts. The toothed wheel 13 meshes with a pinion 14 fixed to an axis 7, rotating the field source 3. A return element 11, such as a spring, makes it possible to replace the pusher element 5 in its starting position.

Similarly to the previous example, it is possible to integrate a more complex gear train, such as that shown in FIG. 5, to ensure that a translational movement, even of small amplitude, can result in angular rotation. sufficient source 3 of at least 90 °, within 30 °.

The integration into the gear of elements of the pinion and conical wheel type can also make it possible to place the displacement of the pusher element 5 in a different angular position than that which is shown and which has been described. And one can also provide in this example, a device for end-of-travel lock as has been explained in connection with the first example.

In certain configurations the pinion 14 can be omitted, by providing the outer contour of the cylinder 3 with teeth cooperating with the toothed wheel 13.

The walls 8 of the housing allow it to maintain the elements of the generator 1 within a compact volume.

Figure 7 schematically shows a third example of implementation of the invention according to its first embodiment. As in the two previous examples, a converter

2 of circular shape is placed on a wall 8 of a housing la, inside the housing 4 of a magnetic field source 3 consisting of a Halbach cylinder. The field source 3 is not fixed to the support 8, it is free to move in rotation. This movement can be facilitated by providing the support walls 8 with which it is in contact with ball bearings, rollers, lubricating materials, etc.

The transmission device comprises a cylindrical body 16, provided with a first pattern 17 such as a groove or a helical rib. The pusher element 5 is integral with a circular face of the body 16. The inside of the cylinder 3 is provided with a second pattern, rib or groove, complementary and cooperating with the first patterns 17 of the body 16. A pressure on the pusher element 5 leads to its displacement in translation along an axis perpendicular to the reference plane, and rotates the source 3. The choice of the pitch of the pattern 17 makes it possible to determine the angular displacement of the source 3 for the translation amplitude permissible from the pusher element 5. It is also chosen to allow the reversible transmission of the rotational and translational movements of each of these parts. Returning means 11 are in contact with the wall of the support (or with the converter 2 as shown in FIG. 7 and with a surface of the cylindrical body 16 so as to replace the pusher element 5 (and the body 16). In its initial position, as in the preceding examples, it is also possible to provide a limit-of-travel locking device as has been explained in connection with the first example of this embodiment of the invention.

As in the preceding examples, the displacement of the pusher element 5 in translation leads to the formation of a rotating magnetic field in the reference plane of the converter 2 and to the accumulation of charges that can be collected by the control device associated with the generator 1.

FIG. 8 schematically represents a view from above of a fourth embodiment of the invention according to its first embodiment.

The pusher element 5 is integrally attached to a transmission belt 19. The displacement of the transmission belt 19 and the pusher element is guided by at least two rollers 18a, 18b fixed on a wall 8 but free to turn on them -Same. Advantageously, the transmission of the movement between the belt 19 and the rollers 18a, 18b is carried out without sliding. This can be done by using a synchronous belt having teeth whose shape is chosen to mesh with the teeth that can be provided with the rollers 18a, 18b. Alternatively, we can choose a transmission belt 19 in the form of a chain.

The transmission belt 19 and the two rollers 18a, 18b form the device for transmitting the displacement in translation of the pusher element 5 in a rotational movement of the magnetic field source 3 to vary this magnetic field in the reference plane. of the converter. To do this, a circular-shaped converter 2 is placed on the wall 8, inside the housing 4 of a magnetic field source 3 consisting of a Halbach cylinder which can be rotated by the transmission belt 19 .

The displacement of the pusher element 5 in translation causes the transmission belt 19 to move and the magnetic field source 3 to rotate. This rotation leads to the formation of a rotating magnetic field in the reference plane of the magnet. converter 2 and the accumulation of charges that can be collected by the control device associated with the generator. According to the same principle, the converter 2 could be rotated rather than the source of fields 3 in order to produce a variable field in the reference plane of the converter 2.

Second embodiment

In this second embodiment, the pusher element 5 is integral with the field source 3 or the converter 2. The pusher element 5 is displaceable in translation in a direction perpendicular to the reference plane, and thus causes in displacement the source 3 or the converter 2 to which it is attached.

In a first position of the pusher element 5, the converter 2 is placed in the housing 4 of the source 3 at a first plane and subjected to a first configuration of the field.

By "field configuration" is meant the intensity and the orientation of the magnetic field (in particular with respect to the direction of polarization of the converter 2) at any point in the space of the housing 4 occupied by the converter 2 , at the level of its reference plane. The pusher element 5 moved in a second position moves the source 3 or the converter 2 to which it is fixed. When the pusher element 5 is in the second position, the converter 2 is subjected to a second field configuration in its reference plane. This second field configuration is different from the first one.

The variation of field between the first position and the second position of the pusher element 5 at the level of the reference plane leads to the generation of charges in the piezoelectric layer or layers 21a, 21b of the converter 2, and to their accumulation on the electrodes .

A return element 11, such as a spring makes it possible to reposition the pusher element 5 in its first or second position.

Figures 9a and 9b schematically show a first example of implementation of the invention, in this second embodiment.

In FIG. 9a, the pusher element 5, integral with the converter 2, is in its first position. The converter 2 is placed in the housing 4 of a field source 3 whose constitution can be chosen according to what has been explained in the common part to all the embodiments of the invention. This source 3 is fixed to the walls of a support 8.

Figure 9b shows the generator 1 when the pusher element 5 is in its second position, after it has been moved in translation.

In this first example, the converter 2 has been driven out of the housing 4 defined by the source 3. It is then no longer subject to the field prevailing in this housing 4 but to a peripheral field which is different from the housing field, much lower intensity, and orientation that can be any. This field variation induces the generation of charges on the piezoelectric layers 21a, 21b of the converter 2 and their accumulation on the electrodes 22a, 22b. A control device (not shown) may be configured to come into contact with these electrodes when the converter 2 is moved at the end of travel, for example in the second position of the pusher element 5, as shown in FIG. 8b. Alternatively, the electrical connection between the converter 2 and the terminals of the control device can be achieved by conductive springs or by simple wire connections.

To maximize the variations in the perceived field, in the reference plane, by the converter 2 between the first and second positions, and to guard against possible permanent or residual magnetization effects of the magnetostrictive layer, the generator 1 can be provided with of a peripheral field source 19. This source 19 can generate a field whose direction is perpendicular to the reference plane, and be placed near the converter 2 when it is positioned outside the housing 4, that is to say say when the pusher element 5 is in the second position. The peripheral field thus serves to restore an initial level of low magnetization / deformation of the magnetostrictive layer in the reference plane. This ensures that the potential for generating charges is maximized.

In this example, the field source is fixed which allows a greater freedom in its dimensioning. In this case, it will be possible to choose a source 3 of larger size in order to generate a large intensity field in the housing 4 and to maximize the charge generation potential.

Figures 10a and 10b show an alternative to this first example. In the case of this alternative, the pusher element 5 is fixed to the field source 3. It is therefore the source 3 which is this time displaced when the pusher element 5 translates from its first position to the second position. The converter 2 is fixed, its interface with the control device is simplified.

The operation of this alternative is similar in all respects to the operation of the first example just made.

Figures 11a and 11b schematically show a second example of implementation of the invention in the second embodiment.

In this example, the field source 3 is composed of two distinct parts 3a, 3b each of these parts being able to generate a distinct field configuration. By way of example, the part 3a of the source 3 is able to create a first field configuration oriented in a plane parallel to the reference plane and in a first direction. The part 3b of the source 3 is itself able to create a second field configuration oriented in a plane parallel to the reference plane and in a second direction, different from the first. Advantageously, this second direction is 90 ° from the first. The intensity of the field generated by the first part 3a and the second part 3b are not necessarily the same. The source 3 can be constituted simply by an assembly or a stack of permanent magnets whose moments are chosen to orient the fields in the determined direction. It may be, for example, a stack of two identical Halbach cylinders, and offset in the stack from an angular position of 90 ° to 30 °. Figure 11a shows the generator 1 when the pusher element 5 is in the first position. The converter 2 is placed in the housing 4 of the source 3 in a first plane subjecting the layer 20 to a first field configuration generated by the part 3a of the source 3.

Figure 11b shows the generator 1 when the pusher element 5 and in its second position. It is observed in this figure that the converter 2 is then placed in the housing 4 of the source 3 vis-à-vis the part 3b of the source. The converter 2 is then subjected, in its reference plane, to the second configuration of the field. As in the previous example, the variation of field in the reference plane of the converter 2 during the displacement of the pusher element 5 between the two positions leads to the generation of charges in the converter 2 to their accumulation on the electrodes.

In this particular example, the converter is fixed to a wall 8 of the housing 1a, so it is easy to connect it to the control circuit making it possible, among other things, to collect the charges.

It is conceivable, while remaining within the scope of this example, to have a source 3 having more than two parts 3a, 3b, each of the parts making it possible to generate a field configuration distinct from the configurations of the fields generated by the parts which are directly adjacent to it. By judiciously choosing the configuration of each of the fields, for example by shifting the fields of two adjacent parts by 90 ° (within 30 °), it is possible to simulate the application of a rotating field in the reference plane of the converter 2, during its displacement in the housing of the source 3. The amount of collectible charges is thus increased.

As in the preceding example, it is possible to provide a variant in which the pusher element 5 would be fixed to the converter 2, and not to the field source 3. FIGS. 12a to 12c schematically represent a third example of implementation of the FIG. invention according to its second embodiment. In this example, the magnetic source 3 is configured to generate two distinct field configurations according to the position of the converter 2.

As can be seen in the section shown in FIG. 12a, the magnetic source 3 comprises a hollow magnet 20 (and cylindrical in the example shown) and a first and a second permeable magnetic element 21a, 21b arranged on one side. and other of the magnet. The magnetic field from the magnet 20 closes on the converter 2 by circulating in the permeable magnetic elements 21a, 21b. This circulation of the field is represented by the arrows in this figure 12a.

The converter 2 placed in the housing 4 is driven in translation from a first plane parallel to the reference plane to a second plane when the pusher element 5 (not shown in these figures) is moved from its first to its second translational position. . These two positions are respectively shown in Figures 12b and 12c.

The first element and the second permeable magnetic element 21a, 21b are configured to close and orient the magnetic field on the converter 2 in a first field configuration when the converter is in the foreground (Figure 12b).

The first and second magnetic elements 21a, 21b are configured to close and orient the magnetic field of the source 3 on the converter 2 in a second field configuration when the converter is in the second plane (Figure 12c). As in the previous examples, the field variation in the reference plane of the converter 2 between the two positions leads to the generation of charges in the converter 2 and their accumulation on the electrodes. Note that this example of implementation does not exclude that the source 3 and the converter 2, whether they are placed in the first or in the second plane, can be moved in rotation relative to each other for generate a variable magnetic field (for example rotating) vis-à-vis the converter 2. It can in this way generate charges in the converter 2 and accumulate on the electrodes for both rotational movements and translational movements of the pusher element 5. Naturally, the invention is not limited to the embodiments described and variations can be made without departing from the scope of the invention as defined by the claims.

Claims

Generator (1) for transforming a translation movement of a pusher element into an accumulation of electrical charges comprising:

- a converter

(2), comprising a reference plane, and capable of transforming a variation of magnetic field in the reference plane into an accumulation of charges;

- a magnetic field source (3) defining a housing (4) in which a magnetic field reigns;

- the pusher element (5), integral with the source

(3) or the converter (2), being movable in a direction of translation perpendicular to the reference plane of a first position in which the converter (2) is placed in the housing

(4) at a first plane and subjected to a first field configuration in its reference plane, at a second position in which the converter (2) is subjected to a second field configuration in its reference plane, different of the first.

Generator (1) according to the preceding claim, in which the converter (2) is formed of a layer (20) of a magnetostrictive material defining the reference plane, assembled with at least one layer (21a, 21b) of a piezoelectric material .

Generator (1) according to one of the preceding claims comprising return means (11) of the pusher element

(5) in the first or second position.

Generator (1) according to one of the preceding claims in which, in the second position, the converter (2) is placed outside the housing (4) and in which the second field configuration corresponds to a field peripheral to the field source magnetic.

Generator (1) according to the preceding claim in which the magnetic field source (3) comprises an assembly of magnets forming a Halbach cylinder and the first field configuration is a uniform field in the housing (4).

6. Generator (1) according to one of the two preceding claims wherein, in the second position, the peripheral field is perpendicular to the reference plane and comes from a peripheral magnetic field source (19).

7. Generator (1) according to one of claims 1 to 3, wherein, in the second position of the push element (5), the converter (2) is placed in the housing (4) at the level of a second plan.

8. Generator (1) according to the preceding claim in which the field source (3) comprises a stack formed of a first Halback cylinder (3a) generating the first field configuration in the first plane, and of a second cylinder of Halback (3b) generating the second field configuration in the second plane.

9. Generator (1) according to claim 7 or 8 in which the field source (3) comprises a first magnetically permeable element (21a) and a second magnetically permeable element (21b) configured to direct the magnetic field on the converter (2 ) according to the first field configuration when the push element (5) is in the first position and according to the second configuration when the push element (5) is in the second position.

10. Generator (1) according to one of claims 7 to 9 in which the first field configuration and the second field configuration correspond to uniform fields, forming an angle of 90° with each other.

11. Generator (1) for transforming a translation movement of a push element movable from a first position to a second position, in a direction of translation, into a accumulation of electrical charges, the generator comprising:

- a magnetic field source (3) defining a housing (4) in which a magnetic field reigns; a converter

(2), comprising a reference plane, and capable of transforming a variation of magnetic field in this reference plane into an accumulation of charges, the converter (2) being arranged in the housing (4) so as to place a part at the minus of the field in the reference plane;

- a device for transmitting the movement of the pusher element (5) in a rotational movement with an axis perpendicular to the reference plane of the field source or the converter, to vary the magnetic field in the reference plane of the converter .

12. Generator (1) according to the preceding claim, in which the converter (2) is formed of a layer of a magnetostrictive material (20) defining the reference plane, assembled with at least one layer of a piezoelectric material (21a, 21b).

13. Generator (1) according to one of claims 11 to 12 wherein the transmission device comprises a multiplier gear (10).

14. Generator (1) according to one of claims 11 to 13, in which the transmission device is configured so that the movement of the pusher element (5) from the first position to the second position causes the rotation of the magnetic field in the reference plane by an angle greater than or equal to 90°.

15. Generator (1) according to one of claims 11 to 14 comprising return means (11) of the push element (5) in the first position.

16. Generator (1) according to one of claims 11 to 15 in which the magnetic field source (3) is an assembly of magnets forming a Halbach cylinder generating a uniform field in the housing (4).

17. Generator (1) according to one of claims 11 to 16 in which the direction of translation is parallel to the reference plane.

18. Generator (1) according to the preceding claim in which the transmission device comprises a rack (9) secured to the push element (5) cooperating with a toothed wheel (6) secured to the source (3) or the converter ( 2).

19. Generator (1) according to one of claims 11 to 16 in which the direction of translation is perpendicular to the reference plane.

20. Generator according to the preceding claim in which the transmission device comprises a threaded rod (15) secured to the pusher element (5) cooperating with a nut (12) only free to rotate.

21. Generator according to one of claims 11 and 12 wherein the transmission device comprises a transmission belt (19) and at least two rollers (18a, 18b).