Patent Description:
The present invention also relates to a rotor and a stator comprising such a compaction plate, and a rotary electric machine comprising such a rotor and/or a stator.

Generally, a rotor or a stator for an electric machine comprises a magnetic mass made of a plurality of magnetic sheets compacted between two clamping plates connected by tie rods, each compaction plate being a massive plate with a central hole made of steel.

Under the effect of magnetic fields, currents are generated inside the clamping plates warming up the electric machine and deteriorating the performances of the electric machine.

As the performances of the machine is proportional to the length of the stack of magnetic sheets, the clamping plates do not contribute to the performances of the machine.

Further, as the compaction plates are made of steel, they increase the mass of the rotating electric machine, in particular the mass of a rotor comprising the clamping plates deteriorating the performances of the electric machine.

Further, a high frequency power supply signal of the rotating electric machine generates parasitic harmonics during the power conversion of the high frequency power supply signal by a variable frequency power signal.

The parasitic harmonics may also be generated by electromagnetic parts, for example rotor and /or stator slots, of the rotating electric machine supplied with a constant high frequency power supply signal.

The frequencies of the parasitic harmonics of the power supply signal may be for example frequencies more than a fundamental supply frequency equal to the pair of electric poles multiplied by the spinning frequency of the rotor.

The generated parasitic harmonics cause parasitic magnetic flux for example in the massive clamping plates in the rotor and the stator generating core losses and stary load losses warming up the rotor and the stator.

The warming up of the rotor and the stator deteriorate the efficiency of the rotating electric machine.

To minimize the effect of parasitic harmonics in the clamping plates electromagnetic shields are implemented at each end of the magnetic mass.

Electromagnetic shields are made of massive disks of copper or aluminium increasing the mass of the rotor or stator and deteriorating the performances of the electric machine.

Document <CIT> discloses a rotor comprising a laminated core formed by laminating magnetic thin plates and comprising a plurality of magnets arranged in holes of the laminated core. Each end of the laminated core comprises a resin molded plate fixing the magnets in each hole.

The resin molded plates do not warm up under the effect of a magnetic field.

However, the molded plates are not rigid enough to maintain the magnetic mass compacted.

Document <CIT> discloses a stator core with compressing rings, wherein each compressing ring comprises axially arranged annular layer of rings, each ring being made of stator laminations placed next to each other and vacuum-glued with an epoxy resin.

It is known from the prior art to glue the laminated magnetic sheets in order to suppress the compaction plate.

As gluing the magnetic sheets is time consuming, it is adapted for small length magnetic mass, for example for electric machines less than <NUM> kW.

It is therefore proposed to remedy the disadvantages related to a magnetic mass comprising clamping plates according to the prior art, particularly for the magnetic mass incorporated in high power electric machine (more than <NUM> kW).

In view of the foregoing the invention proposes, according to claim <NUM>, a compaction plate for magnetic mass comprising a plurality of laminated magnetic sheets, the laminated magnetic sheets being fixed together with fixing and electric insulating means.

Each laminated magnetic sheet is formed by a plurality of segmented laminated magnetic sheets.

Advantageously, the fixing and electric insulating means comprise glue disposed between two adjacent laminated magnetic sheets.

According to the invention, the fixing and electric insulating means comprise an electric insulating resin and at least one boss on each laminated magnetic sheet, each boss comprising a first face forming a cavity and a second face projecting from the magnetic sheet opposite the first face, the electric insulating resin being disposed between two adjacent laminated sheet, the first face of one laminated magnetic sheet being inserted into the second face of a first adjacent laminated magnetic sheet and the second face of the one laminated magnetic sheet being inserted into the first face of a second adjacent laminated magnetic sheet.

Advantageously, each laminated magnetic sheet comprises at least one tooth comprising notches intended to accommodate electrical windings.

According to still another aspect, a magnetic mass is proposed.

The magnetic mass comprises a plurality of laminated magnetic sheets compacted between two compaction elements, a first compaction element comprising a compaction plate as defined below, the compaction elements being connected by connecting means.

Advantageously, the second compaction element comprises a compaction plate as defined below.

Preferably, the connecting means comprise tie rods in the magnetic mass, the tie rods maintaining the laminated magnetic sheets compacted between the two compaction elements.

Advantageously, the connecting means comprise retaining bars maintaining the laminated magnetic sheets compacted between the two compaction elements.

Preferably, the magnetic mass comprises spacers arranged between two successive bundles of laminated magnetic sheets forming ventilation channels.

According to still another aspect, a rotor and a stator for an electric machine comprising a magnetic mass as defined below is proposed.

Another object of the invention relates to a driving system comprising a rotating electric machine as defined below and a power supply feeding the electric machine with a variable frequency power signal, for example with a high frequency power signal more than <NUM>.

Other characteristics and advantages of the invention will emerge on reading the following description of embodiments of the invention, provided solely by way of non-limiting examples and with reference to the drawings in which:.

<FIG> illustrates an embodiment of a driving system <NUM> comprising a rotating electric machine <NUM> and a power supply <NUM> feeding the rotating electric machine <NUM>.

The rotating electric machine <NUM> comprises a stator <NUM> and a rotor <NUM> logged in the stator <NUM>.

A1 is an axis of revolution of the rotor <NUM> in the stator <NUM>.

The power of the rotating electric machine <NUM> is more than <NUM> KW, for example <NUM> MW.

When the rotating electric machine <NUM> operates in a motor mode generating mechanical power on the rotor <NUM>, the power supply <NUM> may supply a high frequency power signal, the frequency being for example more than the spinning frequency of the rotor equal to the fundamental supply frequency divided by the pair of electric poles of the rotating electric machine <NUM>.

In another embodiment, the power supply <NUM> may supply a variable frequency power signal.

In another embodiment, the rotating electric machine <NUM> operates in a generator mode generating electric power to the power supply <NUM>, the power supply <NUM> being a reversible power supply.

<FIG> illustrates a half-section of the cylindrical stator <NUM> of the rotating electric machine <NUM>.

The stator <NUM> is intended to receive the rotor <NUM> in its central space comprising an axis of revolution A1. The stator <NUM> includes a magnetic mass <NUM> comprising packs of laminated magnetic sheets <NUM> compressed between two compaction elements <NUM>, <NUM> arranged on either side of the stator <NUM> and connected by connecting means comprising retaining bars <NUM> maintaining the laminated magnetic sheets compacted between the two compaction elements <NUM>, <NUM>, the retaining bars <NUM> being evenly distributed as represented here on an outer periphery of the laminated magnetic sheets <NUM>, according to the axial direction A1, and a chassis <NUM> encompassing the magnetic mass <NUM>.

It is assumed that the two compaction elements <NUM>, <NUM> are identical.

In another embodiment, connecting means comprise tie rods evenly distributed on a diameter of the laminated magnetic sheets <NUM>.

Two adjacent laminated magnetic sheets <NUM> may be separated by spacers <NUM> to create a ventilation channels as shown here.

In another embodiment, the magnetic mass <NUM> does not comprise spacers <NUM>.

The stator <NUM> further comprises electrical windings <NUM>.

<FIG> illustrates a partial section of a laminated magnetic sheet <NUM> accommodating electrical windings <NUM> generating magnetic flux.

The laminated magnetic sheet <NUM> comprises teeth <NUM> comprising notches accommodating the electrical windings <NUM>.

<FIG> illustrates a section of an embodiment, not according to the invention, of the compaction elements <NUM>, <NUM>.

Each compaction element <NUM>, <NUM> comprises a compaction plate <NUM> including a plurality of laminated magnetic sheets <NUM>, the laminated magnetic sheets being fixed together with fixing and electric insulating means.

The laminated magnetic sheets <NUM> are made of magnetic steel.

The number of laminated magnetic sheets <NUM> forming the compaction plate <NUM> is chosen so that the compaction elements <NUM>, <NUM> are rigid enough to maintain compacted the magnetic mass <NUM>.

The fixing and electric insulating means comprise glue (represented in strong line) disposed between two adjacent laminated magnetic sheets <NUM>, for example epoxy glue.

In another embodiment, the fixing and electric insulating means comprise varnish on a first side of first laminated magnetic sheet <NUM> and glue on a second side of a second laminated magnetic sheet <NUM>, the first and second sides being in contact.

<FIG> illustrates a section of an embodiment, according to the invention, of the compaction plate <NUM> in which the fixing and electric insulating means comprise an electric insulating resin (strong line) and bosses <NUM>.

Each laminated magnetic sheet <NUM> comprises at least one boss <NUM> comprising a first face <NUM> forming a cavity and a second face <NUM> projecting from the magnetic sheet opposite the first face.

The first face <NUM> of one laminated magnetic sheet <NUM> is inserted into the second face <NUM> of a first adjacent laminated magnetic sheet <NUM> and the second face <NUM> of the one laminated magnetic sheet <NUM> being inserted into the first face <NUM> of a second adjacent laminated magnetic sheet <NUM>.

The electric insulating resin is disposed between two adjacent laminated sheet <NUM>.

In another embodiment, the compaction elements <NUM>, <NUM> are not identical, a first compaction element <NUM> comprises the compaction plate <NUM> and the second compaction element <NUM> comprises a clamping plate.

<FIG> illustrates an axial section of an embodiment of the rotor <NUM>.

The rotor <NUM> comprises a cylindrical magnetic mass <NUM> clamped between two compaction elements <NUM>, <NUM>, short-circuit rings <NUM> in contact with the face of the compaction elements <NUM>, <NUM> opposite to the face in contact with the magnetic mass <NUM>.

In another embodiment, short-circuit rings <NUM> are replaced by short disks.

The magnetic mass <NUM> comprises packs of laminated magnetic sheets <NUM> compressed between the two compaction elements <NUM>, <NUM> arranged on either side of the magnetic mass <NUM> and connected by connecting means comprising tie rods <NUM> maintaining the laminated magnetic sheets <NUM> compacted, the tie rods <NUM> being evenly distributed as represented here on an outer periphery of the laminated magnetic sheets <NUM>, according to the axial direction A1.

In another embodiment, the connecting means comprises retaining bars evenly distributed on a diameter of the laminated magnetic sheets <NUM>.

The magnetic mass <NUM>, the compaction elements <NUM>, <NUM> and the short-circuit rings <NUM> are crossed by a shaft <NUM>.

Conductor bars <NUM> are housed in housings of the magnetic mass <NUM> and evenly distributed over a diameter of the magnetic mass <NUM> so that the shorting rings <NUM> and the conductor bars <NUM> form a squirrel cage.

The short-circuit rings <NUM> and the conductive bars <NUM> are made, for example, of copper or of alloyed copper.

The two compaction elements <NUM>, <NUM> are identical, each comprising a compaction plate made of laminated magnetic sheets <NUM> fixed together with fixing and electric insulating means in the same way as explained above.

In another embodiment, a first compaction element <NUM> comprises the compaction plate and the second compaction element <NUM> comprises a clamping plate.

The rotating electric machine <NUM> implementing the rotor <NUM> is of the squirrel cage asynchronous type.

In another embodiment, the rotor <NUM> may comprise windings replacing the conductive bars <NUM>, the windings and the short-circuit rings <NUM> forming a squirrel cage.

In another embodiment, the rotor <NUM> may comprise windings replacing the short-circuit rings <NUM> and the conductive bars <NUM> forming a winded rotor implemented in a synchronous rotating electric machine.

The removal and the replacement of the clamping plates by laminated magnetic sheets <NUM> permits to decrease the mass of the rotating electric machine <NUM> and to increase the active part generating magnetic flux of the magnetic mass <NUM>, <NUM> improving the efficiency of the rotating electric machine <NUM> for example by improving the generated torque on the rotor <NUM> in motor mode, without increasing the volume of the magnetic mass <NUM>, <NUM> and thus the volume of the rotating electric machine <NUM>, or for example for defined characteristics of a rotating electric rotating electric machine, by reducing the mass and the volume of the machine.

Further, the removal and the replacement of the clamping plates by laminated magnetic sheets <NUM> permits to suppress the electromagnetic shields decreasing even more the mass of the rotating electric machine <NUM>, for example the magnetic mass of the rotor to improve even more the torque generated by the rotating electric machine in motor mode and without warming up the rotor and/or the stator with parasitic harmonics so that the rotating electric machine <NUM> is even more efficient for example by improving the generated torque on the rotor <NUM> in motor or generator modes.

Claim 1:
Compaction plate (<NUM>, <NUM>, <NUM>, <NUM>) for magnetic mass (<NUM>, <NUM>), wherein the compaction plate comprises a plurality of laminated magnetic sheets (<NUM>, <NUM>), and fixing and electric insulating means comprising an electric insulating resin and at least one boss(<NUM>) on each laminated magnetic sheet, each boss comprising a first face forming a cavity (<NUM>) and a second face (<NUM>) projecting from the magnetic sheet opposite the first face, the electric insulating resin being disposed between two adjacent laminated sheet, the first face of one laminated magnetic sheet being inserted into the second face of a first adjacent laminated magnetic sheet and the second face of the one laminated magnetic sheet being inserted into the first face of a second adjacent laminated magnetic sheet, wherein the laminated magnetic sheets are fixed together with the fixing and electric insulating means.