H= * =H *

The present invention relates to a transverse flux electric machine.

Transverse flux electric machines of the prior art have a magnetic flux which crosses a magnetic circuit and which extends into ferromagnetic portions which are positioned in perpendicular direction with respect to the direction of a rotation motion of a rotor. The magnetic flux of the transverse flux electric machines extends in transversal direction and this has as a consequence a partial uncoupling between the electrical circuit and the magnetic circuit. This feature determines the possibility, for the transverse flux electric machines, of being able to increase the space for the windings of without needing to decrease the space available for the magnetic flux.

Another important difference between transverse flux electric machines and traditional machines is the possibility of having a high number of poles which makes it possible to obtain a torque density higher than in the radial or axial flux machines.

The winding of a phase in transverse flux electric machines consists of a simple toroidal element, making it possible to use less copper the produced torque being equal.

Transverse flux electric machines can be divided into machines with the permanent magnets mounted with the rotor and machines with the permanent magnets mounted with the stator. The positioning of the permanent magnets mounted with the stator makes it possible to obtain a machine which is mechanically simpler and more robust; indeed, in this case, the rotor consists of a toothed shaft made of ferromagnetic material.

The presence of the permanent magnets mounted with the stator makes their cooling simpler, avoiding thermal stresses which could demagnetize the permanent magnets and reduce the power of the machine.

Furthermore, the permanent magnets mounted with the rotor are subjected to a centrifugal force. This requires the use of complex and costly 1

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structures.

FR-2358046-A1 is a transverse flux electric machine with magnets mounted with the stator of the stepper type motor, but disadvantageously the magnetic flux is very low if permanent magnets which have a low residual magnetic flux value are used, such as the permanent magnets composed of ferrite.

EP2787612, WO-2015/056268 and EP2860860 describe examples of transverse flux electric machines with magnets mounted with the stator, which however have the disadvantage of not having magnetic flux concentrators, making disadvantageous the use of permanent magnets which have a low residual magnetic flux value, such as the permanent magnets composed of ferrite.

AT505839, WO-03/047067-A2 and DE-10262148-B4 describe a transverse flux electric machine with the permanent magnets mounted on the stator and provided with flux concentrators, the disadvantage of said machine consists in the excessive construction complexity and the high number of components which make assembling complicated. It is the object of the present invention to make a transverse flux electric machine which is easy to construct, mechanically robust, with a relatively low number of components and capable of maintaining high performance also by mounting permanent magnets with a low residual magnetic flux value, such as, for example, permanent magnets composed of ferrite.

In accordance with the invention, such an object is achieved by a transverse flux electric machine according to claim 1.

These and other features of the present invention will become further apparent from the following detailed description of practical embodiments thereof illustrated by way of non-limitative example in the accompanying drawings, in which:

Figure 1 shows a perspective view of a module of a stator;

Figure 1 A shows a front view of the stator module in Figure 1 ; Figure IB shows a section view taken along line A- A in Figure 1 A;

Figure 1 C shows a section view taken along line B-B in Figure 1A;

Figure ID shows a section view taken along line C-C in Figure 1 A;

Figure IE shows a section view taken along line D-D in Figure 1 A;

Figure 2 shows an exploded perspective view of the stator module in Figure 1 , wherein said stator module consists of a first ring and of a second ring, which are mounted along a longitudinal axis with one another and with a coil;

Figure 3 shows a perspective view of a ring of the stator module in Figure 2 according to a first alternative;

Figure 3 A shows a section view taken along line A- A in Figure 3;

Figure 3B shows a section view taken along line B-B in Figure 3;

Figure 4 shows a perspective view of a transverse flux electric machine consisting of a rotor and a stator consisting of three stator modules piled axially along the longitudinal axis according to the first alternative in Figures 3, 3A-3C;

Figure 4A shows a front view of the transverse flux electric machine according to Figure 4;

Figure 4B shows a section view taken along line A-A in Figure 4A;

Figure 4C shows a section view taken along line B-B in Figure 4A;

Figure 4D shows a section view taken along line C-C in Figure 4A;

Figure 5 shows a perspective view of a coil mounted with a cylindrical housing according to a second alternative;

Figure 5 A shows a section view taken along line A-A in Figure 5;

Figure 5B shows a section view taken along line B-B in Figure 5;

Figure 6 shows a perspective view of a coil according to a third alternative mounted with the cylindrical housing of the second alternative;

Figure 6 A shows a section view taken along line A-A in Figure 6;

Figure 6B shows a section view taken along line B-B in Figure 6;

Figure 7 shows an exploded perspective view of a ring of the stator module consisting of an inner annulus and of an outer annulus according to a fourth alternative;

Figure 7A shows a perspective view of the outer portion of the ring of the stator module in Figure 7;

Figure 7B shows a front view of the outer annulus in Figure 7A;

Figure 7B shows a top view of the outer annulus in Figure 7A;

Figure 7D shows a front view of the outer annulus in Figure 7A;

Figure 7E shows a perspective view of the inner annulus of the ring of the stator module in Figure 7;

Figure 7F shows a front view of the inner annulus of the ring in Figure

7E;

Figure 7G shows a side view of the inner annulus of the ring in Figure

7E;

Figure 7H shows a perspective view of the inner annulus of the ring in Figure 7 which mounts the cylindrical housing mounting the coil;

Figure 71 shows a front view of Figure 7H;

Figure 7 J shows a side view of Figure 7H;

Figure 8 shows a perspective view of a ring of the stator module according to a fifth embodiment, wherein said ring consists of a multiplicity of laminate sheets made of ferromagnetic material piled along the longitudinal axis and bent;

Figure 8 A shows a front view of Figure 8;

Figure 8B shows a section view taken along line A-A in Figure 8A; Figure 8C shows a perspective view of the ring in Figure 8 before bending;

Figure 8D shows a laminate sheet of said multiplicity of laminate sheets made of ferromagnetic material before bending;

Figure 9 shows an alternative ring of the stator module comprising a higher number of teeth facing towards the rotor than a number of poles of magnetic circuit; Figure 10 shows a further alternative ring of the stator module comprising a lower number of teeth facing towards the rotor than a number of poles of magnetic circuit;

Figure 11 shows a perspective view of a stator module comprising permanent magnets facing towards opposite poles;

Figure 12 shows a front view of a stator module according to a sixth alternative which mounts a single outer permanent magnetic ring;

Figure 12A shows a section view taken along line A- A in Figure 12;

Figure 12B shows a section view taken along line B-B in Figure 12; Figure 12C shows a section view taken along line C-C in Figure 12;

Figure 12D shows a section view taken along line D-D in Figure 12;

Figure 13 shows a front view of the stator module in Figure 12 which mounts by fitting a single, toothed, outer permanent magnetic ring according to a seventh alternative;

Figure 13 A shows a section view taken along line A- A in Figure 13 ;

Figure 13B shows a section view taken along line B-B in Figure 13;

Figure 13C shows a section view taken along line C-C in Figure 13;

Figure 13D shows a section view taken along line D-D in Figure 13;

Figure 14 shows a perspective view of an alternative stator which envisages an outer rotor.

A stator 2 of a transverse flux electric machine 1 can be seen the figures above. The transverse flux electric machine 1 consists of a stator 2 and of a rotor 3, as shown for example in Figure 4.

The rotor 3 of the transverse flux electric machine 1 consists of a rotating shaft, said rotating shaft comprising a multiplicity of teeth 30 which radially protrude outwards, i.e. towards the stator 2. Each tooth 30 of the rotor 3 has the same shape as the other teeth 30 of the rotor 3. Each tooth 30 is arranged so that between one tooth 30 and the other 32 there is the same distance measured on a geometric arc of circumference and the teeth 30 are spaced apart by the same angle. The rotor 3 is made of ferromagnetic material.

As shown in figures 1 and 2, the stator 2 of the transverse flux electric machine 1 comprises at least one stator module 11 , wherein said stator module 1 1 consists of a first ring 21, of at least one coil 51 , of a second ring 31 and of at least one permanent magnet 41. Said first ring 21 can be separably mounted with said second ring 31 along a longitudinal axis L of the transverse flux electric machine 1. At least one coil 51 is mounted along the longitudinal axis L between said first ring 21 and said second ring 31. The longitudinal axis L means the axis of the transverse flux electric machine 1. At least one coil 51, which axially separates the first ring 21 from the second ring 31 of the stator module 1 1, is mounted between the first ring 21 and the second ring 31.

An axial length measured along the longitudinal axis L of the stator module 11 is given by the sum along the longitudinal axis L of an axial length of the first ring 21, of an axial length of the coil 51 and of an axial length of the second ring 31.

As shown in Figures 1, 2, 9, 10, each ring 21, 31 of the first ring 21 or of the second ring 31 consists of two portions of annulus shape 301, 302. Said two portions of the ring 21 , 31 are two annuli 301, 302 which are radially concentric, a first outer annulus 301 and a second inner annulus 302. The first annulus 301 is integrated with the second annulus 302 to form the ring 21, 31 of the stator module 11. Each ring 21, 31 consists of the first annulus 301 and of the second annulus 302, wherein said first annulus 301 is radially concentric with said second annulus 302. Said second annulus 302 faces towards the rotor 3, i.e. said second annulus 302 comprises a surface facing radially towards the rotor 3.

As shown in particular in Figures 1, 1A-1D, the first annulus 301 of each ring 21, 31 comprises a multiplicity of poles of magnetic circuit 23, 33, which concentrate the magnetic flux and which extend from a surface 21 1, 311 of the first annulus 301 facing the direction opposite to the rotor 3, i.e. outwards. Each pole of magnetic circuit 23, 33 of the ring 21 , 31 has the same shape as the other poles of magnetic circuit 23, 33 of the ring 21, 31. Each pole of magnetic circuit 23, 33 is arranged so that there is the same distance measured on a geometric arc of circumference corresponding to the first annulus 301 between one pole of magnetic circuit 23, 33 and the other

23, 33 of the same first ring 21, 31 and the poles of magnetic circuit 23, 33 of the same ring 21, 31 are spaced apart by the same angle.

The first annulus 301 of the first ring 21 comprises a multiplicity of poles of magnetic circuits 23 which extend radially from a surface 211 of the first annulus 301 of the first ring 21 which faces in radial direction opposite to the rotor 3. The poles of magnetic circuit 23 are positioned at regular distances from each other. Each pole of magnetic circuit 23 of the first ring 21 has the same shape as the other poles of magnetic circuit 23 of the first ring 21. Each pole of magnetic circuit 23 is arranged so that there is the same distance measured on a geometric arc of circumference corresponding to the first annulus 301 between one pole of magnetic circuit 23 and the other 23 of the same first ring 21 and the poles of magnetic circuit 23 of the same first ring 21 are spaced apart by the same angle. In other words, each magnetic circuit pole 23 of said multiplicity of poles of magnetic circuit 23 is arranged so that each pole of magnetic circuit 23 of the same ring 21 is distanced from the adjacent pole of magnetic circuit 23 by a same angular distance. The pole of magnetic circuit 23 of the first ring 21 extends axially along the longitudinal axis L towards the second ring 31 of the stator module 11. The axial length along the longitudinal axis L of the pole of magnetic circuit 23 corresponds to the axial length of the stator module 1 1 along the longitudinal axis L.

The first annulus 301 of the second ring 31 comprises a multiplicity of poles of magnetic circuits 33 which extend radially from a surface 311 of the first annulus 301 of the second ring 31 which faces in radial direction opposite to the rotor 3, i.e. outwards. The poles of magnetic circuit 33 are P T/EP2017/058821

positioned at regular distances from each other. Each pole of magnetic circuit 33 of the second ring 31 has the same shape as the other poles of magnetic circuit 33 of the second ring 31. Each pole of magnetic circuit 33 is arranged so that there is the same distance measured on the geometric arc of circumference corresponding to the first annulus 301 between one pole of magnetic circuit 33 and the other 33 of the same second ring 31 and the poles of magnetic circuit 33 of the same second ring 31 are spaced apart by the same angle. In other words, each magnetic circuit pole 33 of said multiplicity of poles of magnetic circuit 33 is arranged so that each pole of magnetic circuit 33 of the same second ring 31 is distanced from the adjacent pole of magnetic circuit 33 by a same angular distance. The pole of magnetic circuit 33 of the second ring 31 extends axially along the longitudinal axis L towards the first portion 21 of the stator module 1 1. The axial length along the longitudinal axis L of the pole of magnetic circuit 33 corresponds to the axial length of the stator motor 1 1 along the longitudinal axis L.

The axial length along the longitudinal axis L of the pole of magnetic circuit 23 of the first ring 21 is equal to the axial length along the longitudinal axis L of the pole of magnetic circuit 33 of the second ring 31.

Said multiplicity of poles of magnetic circuit 23 of the first ring 21 is drifted by an angle with respect to said multiplicity of poles of magnetic circuit 33 of the second ring 33 so that the poles of magnetic circuit 23 of the first ring 21 are aligned along the longitudinal axis L with a space between two adjacent poles of magnetic circuit 33 of the second ring 31.

The surface 211 of the first annulus 301 of the first ring 21 comprises a multiplicity of radially carved portions 233 in direction of the rotor 3, i.e. inwards. Each radially carved portion 233 is arranged at a regular distance from one another and between two adjacent poles of magnetic circuit 23 of the same first ring 21. The position of the radially carved portion 233 corresponds to the position of the pole of magnetic circuit 33 of the second ring 31, so that when the pole of magnetic circuit 33 of the second ring 31 is over the respective radially carved portion 233 of the first ring 21, the magnetic circuit pole 33 of the second ring 31 avoids the contact with the first ring 21. Each radially carved portion 233 of the first ring 21 has the same shape as the other poles of magnetic circuit 233 of the first ring 21. The shape of the radially carved portion 233 is complementary with respect to the shape of the magnetic circuit pole 33 of the second ring 31. Each radially carved portion 233 is arranged so that there is the same distance measured on the geometric arc of circumference corresponding to the first annulus 301 between each radially carved portion 233 and the other 233 of the same first ring 21 and the radially carved portions 233 of the same first ring 21 are spaced apart from one another by the same angle.

The surface 311 of the first annulus 301 of the second ring 31 comprises a multiplicity of radially carved portions 323 facing in direction of the rotor 3, i.e. inwards. Each radially carved portion 323 is arranged at a regular distance from one another between two adjacent poles of magnetic circuit 33 of the same second ring 31. The position of the radially carved portion 323 corresponds to the position of the pole of magnetic circuit 23 of the first ring 21, so that when the pole of magnetic circuit 23 of the first ring 21 is over the respective radially carved portion 323 of the second ring 31, the magnetic circuit pole 23 of the first ring 21 avoids the contact with the second ring 31. Each pole of magnetic circuit 323 of the second ring 31 has the same shape as the other poles of magnetic circuit 323 of the second ring 31. The shape of the radially carved portion 323 is complementary with respect to the shape of the magnetic circuit pole 23 of the first ring 21. Each radially carved portion 323 is arranged so that there is the same distance measured on the geometric arc of circumference corresponding to the first annulus 301 between one radially carved portion 323 and the other 323 of the same second ring 31 and the radially carved portions 323 of the same second ring 31 are spaced apart from one another by the same angle. When said stator module 11 is in mounted position, the first ring 21 is mounted with a coil 51 and with said second ring 31 along the longitudinal axis L. In the mounted position of the stator module 11, the pole of magnetic circuit 23 of the first section 21 and the pole of magnetic circuit 33 of the second section 31 constitute a magnetic circuit. When said stator module 1 1 is in mounted position, said poles of magnetic circuit 23, 33 are called magnetic flux concentrators. Magnetic flux concentrator 23, 33 means a ferromagnetic element in contact with one or more permanent magnets 41 which has the function of concentrating the magnetic flow exiting from the permanent magnets 41.

Indeed, a permanent magnet 41 is mounted between a pole of magnetic circuit 23 of the first ring 21 and a nearby pole of magnetic circuit 33 of the second ring 31, as shown in Figure 1, 1A-1D.

As shown in Figures 11-13, at least one permanent magnet 41 of the transverse flux electric machine 1 is in contact with the pole of magnetic circuit 23 of the first ring 21 and in contact with the pole of magnetic circuit 33 of the second ring 31.

Said at least one permanent magnet 41 comprises a first magnetic pole oriented towards the pole of magnetic circuit 23 of the first ring 21 and a second magnetic pole oriented towards the pole of magnetic circuit 33 of the second ring 31.

As shown in particular in Figures 1, 1A-1D, 2, the second annulus 302 of each ring 21, 31 comprises a multiplicity of teeth 22, 21 which radially extend towards the rotor 3, i.e. inwards. Said multiplicity of teeth 22, 32 extend radially from the surface of the second annulus 302 facing towards the rotor 3. The teeth 22 of the first ring 21 corresponding along the longitudinal axis L with the teeth 32 of the second ring 31 of the stator module 1 1.

The second annulus 302 of the first ring 21 comprises a multiplicity of teeth 22 which radially extend from the surface of the second annulus 302 of the first ring 21 facing the direction of the rotor 3, i.e. inwards. The teeth 22 are positioned at regular distances from each other. Each tooth 22 of the first ring 21 has the same shape as the other teeth 22 of the first ring 21. Each tooth 22 is arranged so that there is the same distance measured on a geometric arc of circumference corresponding to the second annulus 302 between one tooth 22 and the other 22 of the same first ring 21 and the teeth 22 of the same first ring 21 are spaced apart by the same angle.

The second annulus 302 of the second ring 31 comprises a multiplicity of teeth 32 which radially extend from a surface of the second annulus 302 of the second ring 31 facing the direction of the rotor 3, i.e. inwards. The teeth 32 are positioned at regular distances from each other. Each tooth 32 of the second ring 31 has the same shape as the other teeth 32 of the second ring 31. Each tooth 32 is arranged so that there is the same distance measured on a geometric arc of circumference corresponding to the second annulus 302 between one tooth 32 and the other 32 of the same second ring

31 and the teeth 32 of the same second ring 31 are spaced apart by the same angle.

Each tooth 22 of the first ring 31 has the same shape as the other teeth

32 of the second ring 21.

When said stator motor 11 is in mounted position, all the teeth 22 of the multiplicity of teeth 22 of the first ring 21 are in axis along the longitudinal axis L with all the respective teeth 32 of the second ring 31. The number of teeth 22 of the first ring 21 corresponds to the number of teeth 32 of the second ring 31.

As shown in figures 9 and 10, the positions and the poles of the magnetic circuit 23, 33 are independent from the positions of the teeth 22, 32. Indeed, the arrangement of the teeth 22, 32 of the rings 21 , 31 of the stator module 11 depends on the arrangement of the teeth 30 of the rotor 3. Instead, the arrangement of the poles of magnetic circuit 23, 33 of the rings 21, 31 of the stator module 1 1 is independent from the arrangement of the teeth 22, 32 of the rings 21, 31 of the same stator module 11.

Indeed, in figure 9, an alternative ring 21, 31 of the stator module 11 is shown comprising a greater number of teeth 22, 32 facing towards the rotor 3 than a number of poles of magnetic circuit 23, 33. A high number of teeth 22, 32 advantageously makes it possible to obtain a transverse flux electric machine 1 capable of having a high torque at slow speed.

Figure 10, instead, shows a further alternative ring 21, 31 of the stator module 11 comprising a smaller number of teeth 22, 32 facing towards the rotor 3 than a number of poles of magnetic circuit 23, 33. A low number of teeth 22, 32 advantageously makes it possible to obtain a transverse flux electric machine 1 capable of reaching high speeds of the rotor 3.

It is indeed worth noting that the number of magnetic poles of the transverse flux electric machine 1 is independent from the number of permanent magnets 41.

Figure 4 shows a stator 2 comprising three stator modules 1 1 mounted in axis along the longitudinal axis L with one another to form a pile of three stator modules 11. As shown in Figure 4, permanent magnets 41 can be mounted which have a length along the longitudinal axis L which is equal to the sum of the lengths of the single stator modules 11 ; this is made possible by the fact that a multiplicity of stator modules 11 can be piled along the longitudinal axis L of the transverse flux electric machine 1 so that the poles of magnetic circuit 23 of the first rings 21 of different stator modules 1 1 are aligned along the longitudinal axis L. In said alternative, the use of a permanent magnet 41 which has a length equal to the sum of the lengths of the single stator modules 11 makes it possible to reduce the number of permanent magnets 41 advantageously allowing to simplify the assembly of the transverse flux electric machine further.

Figure 4 shows the transverse flux electric machine 1 which works as an electric motor, i.e. with the presence of at least three phases, i.e. with three stator modules 1 1. The rotation of the rotor 3 is caused by the P2017/058821

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activation in sequence of the three phases allowing to divert the flux generated by the permanent magnets 41 in the magnetic circuit 23, 33 consisting of the stator active phase 2 and of the respective teeth 30 of rotor 3. The teeth 30 of rotor 3 are mutually drifted at each phase of stator 2. For a three-phase transverse flux electric machine 1, the teeth 30 of the rotor 3 face the teeth 22, 32 of the first phase of stator 2 are drifted by 120° with respect to the teeth 30 of rotor 3 which face the teeth 22, 32 of the second phase of stator 2 and drifted by 240° with respect to the teeth 30 of rotor 3 which face the teeth 22, 32 of the third phase of stator 2.

Alternatively, the operation of the transverse flux electric machine 1 with only one or two phases, i.e. with a single stator module 11 or with two stator modules 11, refers to the operation of the transverse flux electric machine 1 as a generator and in this case continuous motive torque cannot be produced.

According to a first alternative, as shown in Figures 3, 3A-3B, the poles of magnetic circuit 23, 33 of the ring 21, 31 comprise extensions 25 along the longitudinal axis L or openings 24 along the longitudinal axis L. As shown in particular in Figures 4C and 4D, a face of the pole of magnetic circuit 23, 33 facing in direction of the longitudinal axis L of the stator 2 may comprise an extension 25 which extends from the face of the pole of magnetic circuit 23, 33 towards another stator module 11 or may comprise an opening 24 which is carved along the longitudinal axis L on the face of the pole of magnetic circuit 23, 33. Each extension 25 of the pole of magnetic circuit 23, 33 of a first stator module 11 is adapted to penetrate into the corresponding opening 24 of the pole of magnetic circuit 23, 33 of another stator module 11 piled along the longitudinal axis L with the first stator module 11. As shown in particular in Figure 4C, the pole of magnetic circuit 23, 33 of a first stator module 1 1 comprises two extensions 25 on the respective faces in axis, while a second stator module 11 separably piled with the first stator module 1 1 comprises a pole of magnetic circuit 23, 33 P2017/058821

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comprising openings 24 on both faces in axis with the pole of magnetic circuit 23, 33 of the first stator module 11.

As shown in Figure 3, the teeth 22, 32 of at least one of the two rings 21 , 31 of one same stator motor 11 may comprise an axial portion 26 which extends axially along the longitudinal axis L from the tooth 22, 32 in direction of the other ring 31, 21 of the same stator module 11. Said axial portion 26 is adapted to keep the coil 51 in position.

According to a second alternative shown in Figure 5, the coil winding 51 can be replaced by a cylindrical housing 411 about which the coil 51 is wound. Said cylindrical housing 411 comprises a multiplicity of axial teeth 212 adapted to be fitted into spaces between teeth 22, 32 of the annulus 302 of the ring 21, 31 of the stator module 11, as for example in Figures 7H, 71. Said multiplicity of axial teeth 212 of the cylindrical housing 411 advantageously contributes to fitting the various parts of the transverse flux electric machine 1 keeping them together in firmer manner.

According to a third alternative shown in figure 6, the coil 51 is a flat wire wound about the cylindrical housing 411 of the second alternative. Advantageously, the flat wire simplifies the making of the coil and improves heat dissipation.

Figures 7, 7A-7J show a ring 21, 31 according to a fourth alternative, wherein the first annulus 301 and the second annulus 302 are two separate parts i.e. two separate parts assembled, where said first annulus 301 can separably mounted with said second annulus 302 and form the ring 21, 31. In said fourth alternative, the ring 21, 31 is divided into two portions by a circumferential cut which forms the first annulus 301 and the second annulus 302. Advantageous, said fourth alternative makes it possible to eliminate the torques which are applied between the first annulus 301 and the second annulus 302 of the ring 21, 31 with respect to the alternative in which the first annulus 301 is integrated with the second annulus 302. Indeed, since the first annulus 301 is separated from the second annulus 302, P2017/058821

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the torques that the second annulus 302 receives from the rotor 3 are not transferred to the first annulus 301 which is directly in contact with the permanent magnets 41. This prevents them from damaging the permanent magnets which are mechanically more fragile than the permanent magnets 41 made of ferrite.

Alternatively as shown in Figure 14, the rotor 3 is an outer ring of the stator 2. In said alternative, said rotor 3 consists of a ring-shaped rotating shaft, where said rotating shaft comprises a multiplicity of teeth 31 which extend radially inwards, i.e. towards the stator 2. In said alternative, the pairs of flux concentrators 23, 33 face inwards, instead of outwards, and the teeth 22, 32 of the stator module face outwards, i.e. towards the rotor 3, instead of inwards. In said alternative, the first annulus 301 becomes the inner annulus and the second annulus 302 becomes the outer annulus.

According to a fifth alternative shown in figures 8, 8A-8D, an alternative ring 21, 31 consists of a plurality of laminate sheets of ferromagnetic material (Figure 8D) which are piled one onto the other in axial direction along the longitudinal axis (Figure 8C) and appropriately bent in axial direction as shown in figures 8, 8 A and 8B to form a ring 21, 31 of the shape of the present invention. Advantageously, the laminate sheets which may also be stamped laminates make it possible to considerably reduce the eddy currents by virtue of being glued to one another by means of an insulation.

According to a sixth embodiment shown in figure 12, the permanent magnet 41 is a single outer ring 701 in contact with the poles of magnetic circuit 23, 33 of the rings 21, 31 of the stator module 1.

According to a seventh alternative shown in figure 13, the outer ring 801, which is a permanent magnet 41, comprises a multiplicity of teeth 803 which extend towards the first annulus 301 of the rings 21, 31, said multiplicity of teeth 803 is adapted to fit together with said multiplicity of poles of magnetic circuit 23, 33 of the rings 21, 31. Alternatively,the shape of the radially carved portion 233 is such not to come into contact with the pole of magnetic circuit 33 of the second ring 31 and the shape of the radially carved portion 323 of the second ring 31 is such not to come into contact with the pole of magnetic circuit 23 of the first ring 21.

Again alternatively, the permanent magnets 41 may have cylindrical shape or semi-arc shape to allow a further and advantageous assembly simplification of the transverse flux electric machine 1.

A yet further alternative envisages that the stator modules 11 are made of sintered material, from mild magnetic material powders.

Alternatively, permanent magnets can be envisaged with different magnetic properties, i.e. magnetic energy, residual induction and cohesive force, so as to obtain a magnetic assembly with the desired magnetic properties.

Advantageously, the transverse flux electric machine 1 according to the present invention is easy to make, with a very simplified structure and mechanically more robust with respect to the prior art, with a low number of components and capable of maintaining high performance also by mounting permanent magnets with a low residual magnetic flux value, such as, for example, permanent magnets consisting of ferrite.