FR3124659A1 - ELECTROMAGNETIC MACHINE WITH LINEAR MOTION COMPRISING MAGNETIC RODS - Google Patents

Abstract

ELECTROMAGNETIC MACHINE WITH LINEAR MOTION COMPRISING MAGNETIC RODS The invention presents an electromagnetic machine (1) extending along a longitudinal axis (L), comprising: - a frame, - a stator arranged to create a magnetic field, comprising at least two stator elements (31, 32, 33, 34, 35, 36) arranged around the longitudinal axis (L) and extending in a circumferential or orthoradial direction with respect to the longitudinal axis, - a part linearly movable, comprising at least two distinct rods (41, 42, 43, 44, 45, 46) movable along respective drive axes (E1, E2, E3, E4, E5, E6), and spaced along a circumference extending around the longitudinal axis, each rod comprising at least one magnetic element, each rod being disposed between two stator elements and magnetically movable relative to the at least two stator elements. Figure of the abstract: Fig. 1

Description

ELECTROMAGNETIC MACHINE WITH LINEAR MOTION COMPRISING MAGNETIC RODS

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of electromagnetic machines, of the motor or generator type, the moving part of which performs a linear translation movement.

STATE OF THE ART

From the state of the art document FR3074620 is known an electromagnetic machine comprising a stator, a moving armature and a device for mechanically connecting the moving armature to the stator, the connecting device comprising a plurality of leaf springs. The stator comprises at least a first magnetic core, carrying two electric coils, forming at least one open loop between first and second terminal ends of this first loop to define an air gap between these terminal ends. The mobile armature carries two permanent magnets aligned and of reversed polarity with respect to each other. When a magnetic flux is generated in the air gap, a transverse force shifts the movable armature in a first direction while causing a bending of the leaf springs opposing this displacement in this first direction. Under the effect of current switching in the coils, the magnetic flux crossing the air gap is reversed. This results in a transverse force shifting the movable armature in a second direction. By reversing the magnetic fluxes in the opposite directions, via current switching in the coils, an alternating movement of the armature relative to the support is generated, the springs exerting a restoring force which, at certain frequencies, amplifies the efficiency of the motor .

However, in the case where several mobile armatures are desired, the size of this machine is a disadvantage.

Application EP3029819 discloses a linear actuator comprising three motors. Each motor includes a permanent magnet stator and rod. The three rods can be set in motion through the electromagnetic forces of the respective stators, comprising an electric wire winding. However, it is not specified the number and arrangement of the magnets or even the arrangement of the stator.

He is therefore keen to offer a simple solution, allowing adjustment of the frequency and amplitude of the rods, and offering a reduced size.

OBJECT OF THE INVENTION

To this end, and according to a first aspect, the invention proposes an electromagnetic machine extending along a longitudinal axis, characterized in that it comprises:
- a frame,
- a stator arranged to create a magnetic field, comprising at least two stator elements arranged around the longitudinal axis and extending in a circumferential or orthoradial direction with respect to the longitudinal axis,
- a linearly movable part, comprising at least two separate rods movable along respective drive axes, and spaced apart along a circumference extending around the longitudinal axis, each rod comprising at least one magnetic element, each rod being disposed between two stator elements and magnetically movable relative to the at least two stator elements.

The electromagnetic machine according to the invention has the advantages of proposing a small number of elements, a reduced size and of allowing a back and forth movement at high frequency. This arrangement also makes it possible to provide an electromagnetic machine offering a low manufacturing and maintenance cost.

By stator is meant the fixed part of the electromagnetic machine. It is fixed to the frame of the machine. Preferably, the stator consists of a stack of sheet metal plates made of ferromagnetic materials, preferably soft iron, and a winding of a conductive wire. The stator generates the electromagnetic field when an electric current passes through the conductor wire.

By stator element is meant a part of the stator generating a portion of the electromagnetic field. Preferably, each stator element comprises a central stack of sheet metal plates, which is surrounded by a winding, and two air gap stacks, each air gap stack being arranged at one end of the central stack. Depending on the shape of the machine, each stator element has at least one rectilinear or arcuate portion. Each air gap stack has a distal end which is intended to be arranged facing a rod. The distal end of an air gap stack has a shape which is arranged to partially surround a rod of the moving part. Preferably, the distal end has a shape complementary to the shape of the rod. For example, in the case of a cylindrical rod, the distal end of an air gap stack has a concave shape. For the above and for the rest of the description, each stator element connects two rods, each rod being spaced from a distal end by an air gap.

Preferably, each stator element comprises a set of at least two distinct stacks of sheet metal plates spaced apart longitudinally so as to produce two portions of distinct magnetic circuits.

For example, the sheets can be fed by one or more coils.

The linearly movable part comprises at least two magnetic rods. Each rod comprises at least one magnetic element or consists of a magnetic element. Alternatively to the rods, the moving part of the machine can include any movable part that can carry or be made up of at least one magnetic element. The at least one magnetic element is integrated into the outer casing of the rod or of said part, or it has a general external shape identical to the rod or of said part.

Preferably each rod comprises at least two pairs of alternating poles. According to a variant embodiment, each rod comprises at least four pairs of alternating poles. Preferably, each rod comprises several opposite magnetic poles.

By a pair of poles is meant a device having a north pole and a south pole. A pole pair is preferably a magnet. For example, each rod comprises or corresponds to at least one permanent magnet. Two pairs of alternating poles are understood to mean two devices as defined above arranged head to tail or in such a way that each pole of a first pair is arranged facing each other with a pole of opposite polarity of the second pair. , or adjacent pair.

According to an embodiment in which each rod comprises at least one permanent magnet, the latter occupies at least 50%, preferably at least 75% of the cross section of said rod. In addition, each permanent magnet may have a shape substantially identical to the shape of said rod. In the case where the movable rod comprises several magnets, these are aligned coaxially along the drive axis of said rod.

Preferably, each rod comprises a spacer arranged between two pairs of poles. In the case where the mobile rod comprises several magnets, each rod comprises a spacer placed between two magnets. This characteristic makes it possible to define a force or an amplitude of movement of the rod carrying said spacer. Spacers can be magnetizable or non-magnetic, depending on the strength and amplitude desired.

According to another embodiment, each rod is made of a ferromagnetic material and of a non-magnetic material. The permanent magnet(s) are removed from the moving part of the machine. Thus, one out of two magnets can be replaced by a magnetic core, the other is non-magnetic. The coil of the electromagnet of a stator element is mounted so as to operate on positive current only and is short-circuited in the opposite case. This allows each rod in oscillatory mode to be alternately attracted by the electromagnetic field of the stator, then repelled, for example by the force of means for returning to position, preferably a spring. Reminder means are described below. This embodiment makes it possible to propose a particularly simplified and inexpensive machine.

According to any type of rod, the at least two rods of the movable part can be spaced along a circle whose longitudinal axis is the center. Preferably, the at least two rods can be spaced equidistantly along a circle whose longitudinal axis is the center.

Preferably, the rods are parallel to each other and to the longitudinal axis.

The rods can have different shapes. According to a cross section, each rod can have a shape, parallelepipedic, rectangular, hexagonal, cylindrical or circular.

In addition, the electromagnetic machine may comprise at least one position return means associated with at least one rod. According to one embodiment, the machine comprises a means of return to position by rod. Preferably, a position return means is an elastic return means, for example a spring, preferably a metal spring, in particular steel. Although each rod performs a back and forth movement, it may be interesting to favor the kinetics of one of the two movements. In normal operation, an electromagnetic machine according to the invention, having movable rods oscillating on a pole pitch or being driven in displacement by control electronics, does not require any means for returning the movable rods. However, it may be interesting to add some in order to optimize the performance of the machine. For example, a spring could be placed at a first end of a movable rod and/or at a second end, opposite the first end, of said movable rod. This characteristic makes it possible to absorb the kinetic energy during a first phase of the inversion of the movement to store it in potential energy then to retransmit it to said mobile rod during the second phase of inversion. These return means also make it possible to avoid any movement of too great amplitude, not controlled, which could lead to premature wear of the machine, or to an involuntary exit of one or more moving rods from the machine. Preferably, the oscillation frequency of the rod is the same as the resonance frequency of the system, in order to consume as little energy as possible for setting it in motion.

Preferably, the electromagnetic machine comprises means for sealing the stator and/or the at least two rods with respect to the external environment.

The sealing means includes rod sealing means. Preferably two rod sealing means are associated with each rod, each means being disposed at one end of the rod. They protect the air gap around each rod.

The means of sealing must protect the machine against the saline atmosphere, the polluted atmosphere or fresh or saline water during immersion. For example, the sealing means can be O-rings, sliding elements providing sealing, flexible bellows (elastomer or metal), or mechanical or a combination of these. The seals can be the following: scraper seal, buffer seal, single-acting seal, double-acting seal, lip seal (or oil seal), spring seal. It is possible to use these seals alone or to combine them in order to obtain different functions, for example to filter the impurities, to carry out a pre-sealing in order to obtain a submerged chamber and therefore a lubrication of the guide linings then another seal allowing complete sealing.

In a complementary manner, the machine, in particular the stator or each wound stator element, can be resin-coated for example with an epoxy or silicone resin. In an even complementary manner, the at least two rods of the moving part can be surrounded by an oil bath, offering the advantage of holding the pressure in the event of deep immersion, or of permanently lubricating and cooling the system.

Preferably, the electromagnetic machine comprises means for guiding in translation, for example bearings, bearings, slideways and/or bushings.

Preferably, the volume delimited by the at least two stator elements and the at least two rods is free at the center. No parts are located within the central part of the machine. This allows various advantages such as:
- allow the passage of a part or a fluid (particularly coolant) in the center,
- gain in volume and weight, which is important for embedded systems,
- allow a better grip of the machine during its handling, or even
- improve the thermal performance of the machine via better cooling.

According to a particular embodiment, the stator comprises six stator elements, and the mobile part comprises six rods. The stator is made up of twelve magnetic circuits, two parallel magnetic circuits per stator element, each made up of a coil, a set of laminations forming its magnetic core. Each rod comprises two magnets fixed to it so as to produce the same magnetic bar. The magnetic circuits are assembled on two levels, and form an alternating circular electromagnetic field, making it possible to pull then push back each rod or bar at high frequency.

Preferably, the movable bars or rods are arranged in phase opposition in an alternating manner. Three rods are 180 degrees out of phase with the other three rods. Preferably, the rods operate at a frequency between 10 and 150 Hz (hertz).

The electromagnetic machine comprises power electronics and/or control means so that the movement of the rods of the moving part is controlled in open loop by the power electronics. Control would be done by means of power electronics making it possible to ripple a voltage at different frequencies, such as an inverter that can vary the effective voltage and the frequency.

According to another embodiment, the machine comprises at least one sensor, such as for example a moving part displacement sensor, or even a current sensor. The power electronics and/or the control means control(s) the movement of the rods of the moving part in a closed loop using information from the at least one sensor.

Preferably, the machine comprises a temperature sensor so as to measure the temperature of said machine, preferably connected directly to the control electronics. It can also be protected against overheating with a thermal fuse. These two components are preferably mounted at the periphery of the coil and advantageously at its center, because the coil is the main component diffusing the heat.

According to a second aspect of the invention, a mechanical assembly is provided comprising an electromagnetic machine, according to one or more of the characteristics of the first aspect of the invention, and an effector mounted at at least one of the distal ends of the at least two rods. Preferably, the effector is connected to all the distal ends of the at least two rods.

Preferably, the effector comprises at least one membrane. Each membrane can be arranged coaxially with the electromagnetic machine and facing an outer face of the frame. Preferably, each membrane has a central opening arranged to be passed through by a fluid.

Preferably, the mechanical assembly comprises at least one flange arranged to cooperate hydraulically with a membrane. According to an embodiment in which the mechanical assembly comprises several membranes, each flange is associated with a single membrane.

For example, each flange can have the following combinable variants:
- be rigid or flexible,
- possess any shape in association with the shape of the membranes,
- be solid, or pierced in the center allowing a venturi effect thanks to the difference in speed,
- present hollows and/or asperities and/or lips for various uses (corrosion resistance, pressure build-up, etc.), and
- be made of specific materials (marine, food, biocompatible, for hydrocarbons, etc.),
- the flange may itself be surrounded by two or more membranes.

According to a particular example, the single flange can be the wall of a hull of a boat or of a nautical device (drone, submarine, etc.).

According to a particular embodiment, the mechanical assembly comprises an electromagnetic machine extending along a longitudinal axis, the machine comprising:
- a frame,
- a stator arranged to create a magnetic field, comprising at least four stator elements arranged around the longitudinal axis and extending in a circumferential or orthoradial direction with respect to the longitudinal axis,
- a linearly movable part, comprising at least two upstream rods and at least two downstream rods, the rods being distinct and movable along respective drive axes, and spaced apart along a circumference extending around the longitudinal axis , each rod comprising at least one magnetic element, each rod being disposed between two stator elements and magnetically movable relative to the at least four stator elements.

Preferably, the at least one magnetic element can be at least one pair of alternating poles, for example one or more permanent magnets.

Preferably, the assembly comprises an upstream membrane connected to the distal ends of the at least two upstream rods, and a downstream membrane connected to the distal ends of the at least two downstream rods. This makes it possible to produce a hydraulic thruster whose flow of liquid propelled by the latter is less turbulent compared to the flow of thrusters known as motors equipped with a propeller.

According to one embodiment, the assembly comprises an upstream flange connected to an upstream face of the frame and placed opposite the upstream membrane, and a downstream flange connected to a downstream face of the frame and placed opposite - screw of the downstream membrane.

During actuation, the back and forth movement of the rods causes the membrane(s) to undulate. Each membrane is used to transform the mechanical energy supplied by the motor into hydraulic energy. Each membrane has a cylindrical shape or preferably a discoidal shape. It is composed of a solid frame, advantageously metallic, and an undulating part made of flexible materials, preferably rubber derivatives. The membrane can be of any shape.

Preferably, each membrane has a central opening which is preferably circular. Preferably, each flange has a tubular section arranged coaxially to the longitudinal axis of the machine and extending through the central opening of the associated membrane. The diameter of the tubular section is strictly less than the diameter of the central opening. The tubular section makes it possible to achieve a Venturi effect for the flow of the fluid passing through the center of the mechanical assembly.

According to a particular embodiment, the assembly may comprise at least two upstream membranes and/or at least two downstream membranes. The upstream and/or downstream membranes may have movements out of phase with each other, preferably the phase difference is 180° (degrees).

Preferably, the assembly comprises an upstream cover, placed upstream of the upstream membrane, and a downstream cover, placed downstream of the downstream membrane. Each cover is fixed to the frame of the electromagnetic machine coaxially with the longitudinal axis of said machine, for example via longitudinal arms connecting each cover to the frame of the machine. Preferably, the face of the cover facing the membrane has a surface substantially identical to the surface of the membrane. The volume delimited longitudinally by a cowl and a flange defines a compression chamber, or a propulsion chamber. When the machine is stopped or in operation, each membrane is located in a compression chamber. The liquid set in motion by a membrane first enters the compression chamber via the circumferential zone of the compression chamber, for example between longitudinal arms connecting the cover to the frame of the machine.

For the foregoing and for the rest of the description, compression chamber and propulsion chamber refer to the same definition, so that one or the other of the expressions may be used interchangeably.

The volume propelled by the upstream membrane is expelled into the free central zone of the machine. The downstream cowl further comprises an opening whose cross section is at least equal to the cross section of the free central zone. The volume propelled by the downstream membrane is expelled into the opening of the downstream cover.

Two compression chamber configurations are possible:

- in series, so that the inlet flow of the downstream compression chamber is connected to the outlet flow of the upstream compression chamber via the free central zone of the machine,

- in parallel, so that each compression chamber has its own inlet flow, each flow entering the compression chamber via an opening or a radial zone upstream and/or downstream and/or at the above and below the membrane.

It is possible to combine these two solutions: a central flow passing through the free central zone and a radial flow can supply the downstream compression chamber.

Each compression chamber corresponds to at least one liquid inlet section and at least one liquid outlet section.

These sections can be multiple and can look like this:

- radially to the thruster,

- parallel to the axis of movement of the thruster

- by a combination of the two previous possibilities.

According to a particular embodiment, the downstream cover comprises a central tube, extending coaxially to the electromagnetic machine. This characteristic makes it possible to create a second flow in a compression chamber through the installation of a tube crossing the compression chamber. The inlet section of this tube will undergo an overpressure and the outlet section (located downstream of the compression chamber) a depression, thus creating a venturi effect and improving the performance of the thruster.

According to other embodiments, the mechanical assembly may comprise no cover, or a single cover: an upstream cover or a downstream cover. In the absence of a cover, there is therefore no longer any compression chamber.

Other applications of the mechanical assembly proposed above are possible, for example vibrating pots, industrial vibrators, in particular the moving parts operating in phase to amplify the vibration, strikers, loudspeakers, saws, jackhammers, sex toys, tools for studying vibration, fatigue, aging, industrial pumps, fans, air compressors, force feedback, sifters, vibratory driving vibrators, thrusters boat, thrusters for nautical toys, such as underwater thrusters, paddles, motorized surfboards, "empty-bilge" pumps, electricity generators, pumps for water games, flow generators (currents, waves , swell) for basins, machine tools (such as a saw or sander), mixers.

DESCRIPTION OF FIGURES

The present invention will be better understood on reading the following description, referring to non-limiting examples of embodiments illustrated by the appended drawings where:

there is a perspective view of an electromagnetic machine with cyclic linear motion according to one embodiment of the invention in which each rod of the moving part comprises two permanent magnets, the machine being seen without its frame;

there is a perspective view of a mechanical assembly according to one embodiment, the assembly comprising a machine conforming to the and two effectors, the two effectors each comprising a discoid membrane, each effector being disposed at one end of the machine;

there is a view in perspective and in longitudinal section of a mechanical assembly comprising an electromagnetic machine according to a second embodiment in which each rod of the movable part comprises four permanent magnets;

there is a perspective view of a mechanical assembly in accordance with , the effectors, or membranes, being seen in a position proximal to the electromagnetic machine;

there is a view conforming to , the effectors, or membranes, being seen in a position distal to the electromagnetic machine;

there is a view conforming to , each rod further comprising two non-magnetic spacers, a spacer between two adjacent permanent magnets;

there is a zoom machine of the , a rod of the movable part, carrying four permanent magnets, being seen in an enlarged manner;

there a view of a hydraulic thruster according to a first embodiment, the thruster comprising an upstream cowl and a downstream cowl;

there is a longitudinal sectional view of a hydraulic thruster in accordance with the ;

there is a zoom of the , the upstream cowl and the upstream membrane being seen enlarged;

there is a view in longitudinal section of a hydraulic thruster according to a second embodiment, in which the upstream cowl comprises a front opening;

there is a view in longitudinal section of a hydraulic thruster according to a third embodiment comprising upstream radial openings and downstream radial openings;

there is a view in longitudinal section of a hydraulic thruster according to a fourth embodiment comprising upstream radial openings, downstream radial openings, and a central tube passing through the upstream cowl.

There presents a first embodiment of an electromagnetic machine 1 with cyclic linear motion extending along a longitudinal axis L. In order to visualize the maximum number of parts, the frame of the machine is not shown.

The machine comprises a static part 3, called a stator, arranged to create an electromagnetic field. The stator comprises six stator elements 31, 32, 33, 34, 35 and 36. Each stator element comprises a stack of sheet metal plates surrounded by an electrical winding. The six stator elements 31, 32, 33, 34, 35, 36 are arranged around the longitudinal axis L and extend in a circumferential direction T with respect to the longitudinal axis L so that the field lines are circumferential passing through all the stator elements.

The machine comprises a linearly movable part 4. It comprises six separate rods 41, 42, 43, 44, 45, 46 movable along respective drive axes E1, E2, E3, E4, E5, E6. The rods are spaced equidistantly along a circumference extending around the longitudinal axis L. This arrangement makes it possible to leave the central zone 10 free. The central zone has a tubular shape.

Each rod has a circular cross-section so that each rod has the shape of a bar. For the rest of the description, the word rod or bar can be used interchangeably. Each rod is disposed between two stator elements. Only an air gap separates each rod from the two stator elements. Each rod comprises two permanent magnets aligned along the rod's drive axis and arranged head-to-tail from a polarity perspective. Each magnet occupies substantially the entire cross section of the rod and has a circular cross section. The rods are magnetically movable relative to the stator elements.

According to a variant embodiment represented by the , each rod of the moving part comprises four permanent magnets, only the rods 43 and 46 are visible. In particular, rod 43 includes permanent magnets 63a, 63b, 63c, 63d, and rod 46 includes permanent magnets 66a, 66b, 66c, 66d. Each permanent magnet has the shape of a tube arranged to fit onto a cylindrical core of each rod.

This arrangement allows the bars to be driven by the stator by following the current magnetic fields produced by the latter. The alignment of the poles with respect to the stator allows the bars to operate in phase or in phase opposition with respect to each other. The alignment of the bars is maintained thanks to the magnetic forces of the magnets. The presence of guide means or additional support parts is not essential, within the framework of a minimalist and/or the least expensive embodiment.

Optionally, two guide pieces, preferably cylindrical, serving as a translation guide for each bar, will be fixed on the ends of each bar. These guide parts are advantageously made of non-magnetic materials in order to minimize magnetic field leakage. These two parts have the other function of connecting part to any effector or moving part that needs to be set in motion.

The presence of several rods makes it possible to deliver a greater force to an effector. Furthermore, the presence of four permanent magnets instead of two permanent magnets also makes it possible to deliver a greater force to an effector.

Referring to Figures 4 to 7, there is presented a particular embodiment of the stator in which each stator element comprises two stator sub-elements so as to produce two parallel magnetic circuits. With reference to the , the stator element 35 comprises two stator sub-elements 35a, 35b and the stator element 34 comprises two stator sub-elements 34a, 34b. Furthermore, the rod 44 of the movable part comprises four permanent magnets 64a, 64b, 64c and 64d. During the movement of said rod 44, the permanent magnets 64a, 64b are designed to face the stator sub-elements 35a and 34a, and the permanent magnets 64c, 64d are designed to face each other. screws of the stator sub-elements 35b and 34b.

Figures 2 to 6 show a mechanical assembly comprising two effectors. Each effector comprises a plastic membrane so as to produce a hydraulic thruster, the electromagnetic machine operating in motor mode. With reference to the , the rods 42, 44 and 46 are connected and controlled simultaneously so as to form a first sub-motor, said upstream motor, and the rods 41 (43 and 45 not visible) are connected and controlled so as to form a second sub-motor -engine, called downstream engine. The ends of the rods 42, 44 and 46 are fixedly connected to an armature carrying a membrane M1, called the upstream membrane. The ends of the rods 41, (43 and 45 not visible) are fixedly connected to an armature carrying a membrane M2, called the downstream membrane. The membranes have a discoidal shape. The sub-motors are electrically phase shifted by 180° (degrees) so that the membranes M1 and M2 are actuated in phase opposition. In particular, the magnets are inverted which allows the magnetic field to be quite circular and not to find itself opposed to the field of the following coil.

For the remainder of the description, the operation and/or movement of a rod of a sub-motor, in this case the rod 44 of the upstream motor, will be described.

With reference to the , the upstream membrane is located in a proximal position with respect to the frame 2 of the machine. The position of rod 44 is such that permanent magnet 64a faces stator sub-elements 35a and 34a and permanent magnet 64c faces stator sub-elements 35b and 34b because the magnetic fluxes induced in the air gaps, between on the one hand the stator sub-elements 35a and 34a and on the other hand the stator sub-elements 35b and 34b, are sufficient to achieve a polarity, for for example a north pole, on one side and a reverse polarity, for example a south pole, on the other side. As each permanent magnet has reverse polarity, magnetic fluxes pass through the permanent magnets and hold them in position.

During current switching in the coils, the magnetic fluxes in the air gaps are reversed so that each pole of a permanent magnet faces an identical polarity, achieving a repulsion force and a translation of the rod 44. Simultaneously, the magnetic fluxes manage to cross the adjacent permanent magnets, of opposite polarities, 64b and 64d so that an attractive force carries out the translation of the rod 44. It follows that the new position of rod 44 is such that permanent magnet 64b faces stator sub-elements 35a and 34a and permanent magnet 64d faces stator sub-elements 35b and 34b, see . The upstream membrane M1 is then located in a distal position.

According to a variant embodiment represented by FIGS. 6 and 7, a spacer, called a spacer, is arranged between two adjacent permanent magnets of opposite polarity. With reference to the , a spacer 164 is disposed between the permanent magnets 64a and 64b, and a spacer 264 is disposed between the permanent magnets 64c and 64d.

The thruster includes control means and/or power electronics so that the motor is capable of being used in a wide range of use cases. For example, it can be powered via the mains, a solar panel network or any other alternative energy installation or in an energy storage system by connecting it through power electronics making it possible to regulate and enslave the Electric power.

Depending on the type of control signal and its form, the motor can fulfill different use cases: in a case of power supply by a direct voltage, the motor is servo-controlled in position. It will therefore keep a precise and repeatable position according to the electrical voltage value supplied. If an alternating voltage is supplied, the motor will be speed-controlled. The value of the electrical voltage makes it possible to adjust the amplitude of the travel of the mobile bars. The frequency of the electrical signal makes it possible to adjust the operating frequency of the motor.

The motor makes it possible to provide high frequency linear motion, in particular up to 500 cycles per second, i.e. operation at 500 Hz.

Figures 8 to 13 show several embodiments of hydraulic thruster arranged to be submerged.

With reference to the , the propellant comprises an upstream cowl C1, arranged upstream of the flange F1, and a downstream cowl C2, arranged downstream of the flange F2, the membranes not being shown. Each cover is fixed to the frame of the electromagnetic machine coaxially with the longitudinal axis L of said machine, for example via longitudinal arms connecting each cover to the frame of the machine. With reference to the , the volume delimited longitudinally between a cover and a flange defines a compression chamber. An upstream compression chamber 111 is defined between the cover C1 and the electromagnetic machine 1. A downstream compression chamber 112 is defined between the cover C2 and the electromagnetic machine 1. When the machine is stopped or in operation, each membrane located in a compression chamber. For example with reference to the , the upstream membrane M1 is set in motion via the rods of the moving part of the electromagnetic machine, so as to produce an undulation. The liquid set in motion by a membrane first enters the compression chamber.

Referring to Figures 8, 9, 10, 12 and 13, the thruster comprises upstream radial openings 121. Referring to Figures 8, 9, 12 and 13, the thruster comprises downstream radial openings 122. The radial openings are delimited circumferentially by the longitudinal arms connecting the covers to the frame of the machine. The radial openings allow the liquid to enter radially into each compression chamber.

The volume propelled by the upstream membrane is expelled into the free central zone 10 of the machine. The volume of liquid propelled by the upstream membrane is expelled into the downstream compression chamber.

Furthermore, according to all the embodiments, the downstream cowl C2 comprises an axial opening 132.

In these so-called parallel configurations, each compression chamber has its own inlet flow, each flow entering the compression chamber via an opening or a radial zone. The downstream cowl further comprises an opening whose cross section is at least equal to the cross section of the free central zone.

With reference to the , there is a so-called series configuration in which the inlet flow of the downstream compression chamber is connected to the outlet flow of the upstream compression chamber via the free central zone of the machine. The propellant comprises a single inlet opening 131 to supply the upstream compression chamber with liquid.

It is possible to combine these two solutions: an axial flow and a radial flow to supply the compression chambers. With reference to the , the upstream cover C1 comprises an opening 131 extending via a central tube which opens into the central zone 10 so as to produce a Venturi effect. According to another embodiment not shown, the tube can open out into the upstream compression chamber. The thruster further comprises upstream radial openings 121 and downstream radial openings 122.

Claims (15)

Electromagnetic machine (1) extending along a longitudinal axis (L), characterized in that it comprises:
- a frame,
- a stator arranged to create a magnetic field, comprising at least two stator elements (31, 32, 33, 34, 35, 36) arranged around the longitudinal axis (L) and extending in a circumferential or orthoradial direction relative to the longitudinal axis,
- a linearly movable part, comprising at least two distinct rods (41, 42, 43, 44, 45, 46) movable along respective drive axes (E1, E2, E3, E4, E5, E6), and spaced apart along a circumference extending around the longitudinal axis, each rod comprising at least one magnetic element, each rod being disposed between two stator elements and magnetically movable relative to the at least two stator elements.
An electromagnetic machine (1) according to claim 1, wherein each rod comprises at least one permanent magnet. An electromagnetic machine (1) according to claim 1 or 2, wherein each rod comprises at least two pairs of alternating poles. An electromagnetic machine (1) according to claim 3, wherein each rod comprises a spacer disposed between two pairs of poles. An electromagnetic machine (1) according to claim 1, wherein each rod is made of a ferromagnetic material and a non-magnetic material. Electromagnetic machine (1) according to one of the preceding claims, in which the at least two rods are spaced apart along a circle whose longitudinal axis (L) is the centre. Electromagnetic machine (1) according to one of the preceding claims, in which each stator element comprises a set of at least two separate stacks of sheet metal plates spaced apart longitudinally so as to produce two separate magnetic circuits. Electromagnetic machine (1) according to one of the preceding claims, comprising at least one position return means, associated with at least one rod. Electromagnetic machine (1) according to one of the preceding claims, comprising means for sealing the stator and/or the at least two rods with respect to the external environment. Electromagnetic machine (1) according to one of the preceding claims, in which the at least two stator elements are arranged so as to define a free central zone. Electromagnetic machine (1) according to one of the preceding claims, in which the stator comprises six stator elements (31, 32, 33, 34, 35, 36), and the movable part comprises six rods (41, 42, 43, 44, 45, 46). Mechanical assembly comprising an electromagnetic machine (1), according to one of the preceding claims, and an effector mounted at at least one of the distal ends of the at least two rods. Assembly according to the preceding claim, in which the effector comprises at least one membrane (M1, M2). Mechanical assembly comprising an electromagnetic machine (1) extending along a longitudinal axis (L), according to one of Claims 1 to 11, the machine comprising:
- a stator comprising at least four stator elements (31, 32, 33, 34, 35, 36),
- a linearly movable part, comprising at least two upstream rods (41, 42, 43, 44, 45, 46) and at least two downstream rods (41, 42, 43, 44, 45, 46), each rod being magnetically movable with respect to the at least four stator elements. Assembly according to the preceding claim, comprising an upstream membrane (M1) connected to the distal ends of the at least two upstream rods, and a downstream membrane (M2) connected to the distal ends of the at least two downstream rods.