MXPA04012144A - Rotary electric motor having a plurality of shifted stator poles and/or rotor poles. - Google Patents

Abstract

A rotary electric motor has a stator with a plurality of axially spaced sets of corresponding stator (3,6) and rotor elements (22,23,24). The stator of each set is an annular ring with poles circumferentially positioned about an axis of rotation. The rotor of each set has a plurality of permanent magnets disposed circumferentially along an annular air gap opposite the stator poles. The permanent magnets of adjacent rotor element sets and/or the poles of adjacent stator sets are offset from each other in the axial direction to cancel the effects of cogging torque produce by each of the sets.

Description

ROTATING ELECTRIC MOTOR THAT HAS A PLURALITY OF STATOR POLES AND / OR DEVIATED ROTOR POLES FIELD OF THE INVENTION The present invention relates to rotating electric motors, very particularly to permanent magnet motors comprising a plurality of stator poles and rotor-spaced apart, rotor magnets or axially spaced stator magnets are deviated from an axial alignment with each other.

BACKGROUND OF THE INVENTION The EU patent application? The previously identified co-pending relationship of Maslov et al., number 09 / 826,423, identifies and focuses on the need for an improved engine that serves simplified manufacturing and that has the capacity for efficient and flexible operational characteristics. In a vehicle driving environment, for example, it is very desirable to achieve smooth operation over a wide range of speeds, while maintaining a high torque result capability with minimal power consumption. Said motor drive of the vehicle should conveniently provide an easy access capability to the various structural components for the replacement of parts with a minimum of inconvenience. The co-pending related EUA applications identified above describe the formation of electromagnetic core segments as magnetically isolated permeable structures configured in an annular ring. With such arrangements, the flow can be concentrated to provide convenient effects compared to prior art modes. As described in the requests for Maslov et al., Mentioned above, the isolation of the electromagnetic core segments allows the individual concentration of flow in the magnetic cores, with a minimum of flow loss or harmful effects of transformer interference with other electromagnetic elements. Operational advantages can be obtained by configuring a single pole pair as an isolated electromagnetic group. The isolation of the magnetic path of the individual pole pair from other pole groups eliminates a flow transformer effect in an adjacent group when the energization of the pole pair windings is changed. The lack of additional poles within the group avoids any of these effects within a group. Additional benefits are described from the use of three dimensional aspects of the motor structure, such as a structural configuration in which axially aligned stator poles and axially aligned rotor magnets provide a highly concentrated flow density distribution. in the active air space of the machine. Said configuration provides a greater number of poles with the same individual active air space surface areas and / or a greater total active air space surface area than conventional motors having the same air space diameter. In addition to the benefits of flow concentration that can be obtained with the configurations described above, newly introduced neodymium-iron-boron (NdFeB) magnetic materials can. produce higher flow concentrations than other permanent magnetic materials previously used in brushless machines, thus increasing torsional production capacity. The use of permanent magnets that produce high density in engines that comprise a large number of poles, presents a concern to improve the undesirable effects that can be introduced by the roughing torque. The roughing torque is produced by the magnetic attraction between the permanent magnets mounted to the motor and those stator poles that are not in a selectively magnetized state. This attraction tends to move the magnet of the rotor to a position of equilibrium opposite to a stator pole to minimize the reluctance existing in between. As the motor is driven to rotate by energizing the stator, the magnitude and direction of the roughing torque produced by the interaction of the magnet with non-energized electromagnetic segments, periodically changes to oppose and increase the torsion produced by the energized stator segments. In the absence of compensation, the roughing torque can change the direction abruptly with the rotation of the rotor. If the roughing torque is of significant magnitude, it becomes a rotating impediment, as well as a source of mechanical vibration that is detrimental to the objectives of precision speed control and smooth operation. As an illustration of the development of the roughing torque, an engine such as the one described in copending application 09 / 826,422 is considered. The detailed description of that application has been incorporated in the present invention. Figure 1 is an exemplary view showing the rotor and stator elements. The rotor element 20 is an annular ring structure having permanent magnets 21 distributed substantially uniformly along a cylindrical rear plate 25. The permanent magnets are rotor poles alternating in magnetic polarity along the inner periphery of the magnetic ring. The rotor surrounds a stator element 30, the rotor and stator elements are separated by an annular radial air space. The stator 30 comprises a plurality of segments of electromagnetic core of uniform construction which are distributed uniformly along the air space.

Each core segment comprises a generally U-shaped magnetic structure 36 that forms two poles having surfaces 32 facing the air space. The legs of the pairs of poles are wound with windings 38, although the core segment can be constructed to accommodate a single winding formed in a portion that links the pair of poles. Each stator electromagnetic core structure is separated, and magnetically isolated, from the adjacent stator core elements. The stator elements 36 are secured to a non-magnetically permeable support structure, thus forming an annular ring configuration. This configuration eliminates the emanation of vague transformer flow effects from the groups of adjacent stator poles. Figure 2 is a partial planar display of two adjacent stator core elements 36, with pole surfaces 32 denoted A-D, relative to the rotor magnets, designated 0-5, during engine operation. The positions of the rotor magnets are shown in (A) - (C) for three instants of time (ti-t3) during a period in which the rotor has moved left to right. At time tlf the winding for the pair of stator poles AB is energized with current flowing in one direction to form a strong south pole at A and a strong north pole at B. The winding for the stator pole pair CD does not is energized The position of the rotor is shown in (A). The north magnet 1 and the south magnet 2 overlap the stator pole A. The south magnet 2 and the north magnet 3 overlap the stator pole B. At that time, the magnet 3 is approaching a position of overlap with the pole C. The south magnet 4 is in substantial alignment with the pole C and the north magnet 5 is in substantial alignment with the pole D. At this time, the motorism torque is produced by the force of attraction between the south pole A and the north pole of magnet 1, the force of attraction between the north pole B and the south pole of magnet 2, and the repulsion force between north pole B and the north pole of magnet 3. Poles C and D have a north magnetization and weak south respectively caused by the attraction of the magnets 4 and 5. This attraction, which seeks to maintain a minimum reluctance is in opposition to the drive torque of the motor. At time t2, the rotor has moved to the position shown in (B). The energization of the windings of the pair of poles A-B has been switched to off. The windings of the pair of C-D poles are not energized. The magnets 1 and 2 are usually in alignment with the A and B poles respectively. The north magnet 3 and the south magnet 4 overlap the pole C. The south magnet 4 and the north magnet 5 overlap the pole D. Poles A and B have a weak south and north magnetization respectively. The stator poles C and D are influenced by the north and south rotor magnets. The pole C is in a flow path between the north pole of the magnet 3 and the south pole of the magnet 4. The pole D is in a flow path between the south pole of the magnet 4 and the north pole of the magnet 5. A torsion The roughing has then resulted in the oppositions of the motor drive torque and the changes in magnitude as the rotor magnets move from a direct alignment with the non-energized stator poles to a partial alignment. At time t3, the rotor has moved to the position shown in (C). The energization of the windings of the pair of poles A-B has been reversed, originating a strong north pole at pole A and a strong south pole at B. The windings of pole pair C-D are not energized. The north magnet 1 and the south magnet 2 overlap the stator pole B. The south magnet 0 and the north magnet 1 overlap the stator pole A. At this time, the south magnet 2 is approaching an overlap position with the pole C. The north magnet 3 is in substantial alignment with the pole C and the south magnet 4 is in substantial alignment with the pole D. As described above, the opposite roughing torque effects the motor torque in a manner that varies with respect to the rotational angular position as the rotation proceeds. The roughing torque is most pronounced at the transition points when a rotor magnet is about to face a stator pole through the air space. An abrupt change in the roughing torque occurs as the leading edge of the generally rectangular surface of a permanent magnet approaches the parallel edge of the rectangular stator pole. The use of high energy density permanent magnet materials such as neodymium-iron-boron (NdFeB) magnetic materials, which impart large flux densities in the air space around the permanent rotor magnets, increases this effect to the extent that an undesirable vibration can be made perceptible. Motors that have a large number of stator poles and rotor poles, such as axially aligned rows of stator poles and rotor magnets, can produce even greater roughing torque effects. In this way, the roughing torque is produced to a varying degree in motors that have unitary stator cores. A variety of techniques have been used to minimize the effects of roughing torque. These techniques attempt to reduce the speed of the reluctance change with respect to the position of the rotor, reduce the magnetic flux in the machine, or change the poles in a unitary stator core so that the roughing torque produced by the individual poles tends to be canceled. mutually. Electronic methods can be employed to control the intensity of the electromagnetic interaction that is carried out between the electromagnetic surfaces and the permanent magnet. These methods have disadvantages since they involve complex control algorithms that run simultaneously with motor control algorithms and tend to reduce the overall performance of the motor. The reduction of the magnetic flux decreases the advantages obtained from the most recent permanent magnet materials and the flow concentration techniques of the co-pending applications identified above. The change of location of the poles in a conventional unitary stator core structure imposes limitations on the size, positions and number of poles, which can avoid an arrangement that provides optimal operation. Other approaches involve modifying the construction of the machine by modifying the shape of the stator poles. Stator poles of the prior art conventionally made of stacked laminations are not easy to modify. The available laminating machining processes are limited in their ability to reconfigure conventional patterns, especially when speaking in terms of three dimensions. A substantial range of modification of such laminated structures is too complex and costly to be feasible. Therefore, there is a need for an effective grinding compensation in engines, particularly those that have high flux density magnitudes and concentrations and that does not detract from efficient operation and control capability to the engines at the same time that it is provided. a feasibility of cost and application. The copending application (case number 57357-023) focuses on this need by configuring stator pole surfaces or magnetic rotor surfaces so that the geometrical configuration of the stator pole surface and the geometrical configuration of the magnetic surface of the rotor are offset in reciprocal relationship. The effect of the biased arrangement is to dampen the rate of change of the roughing torque that is produced by the interaction between a rotor magnet and a pole of a non-energized stator electromagnet as the permanent magnet traverses its rotation path. The ability to selectively configure the stator poles is made feasible through the use of core materials such as a soft, magnetically permeable medium that is amenable to the formation of a variety of custom shapes. For example, the core material can be fabricated from soft magnet graduations of Fe, SiFe, SiFeCo, SiFeP powder material, each of which has unique power loss, permeability and saturation level. These materials can be formed initially in any three-dimensional configuration, thus avoiding the possibility of machining a hard lamination material already formed. Minimizing the effects of roughing torque without detrimentally affecting torsional output capacity remains an important goal.

SUMMARY OF THE INVENTION The present invention meets this need, at least in part, by compensating for the effects of the roughing torque produced in a plurality of axially spaced sets of rotor and stator elements. Additional advantages are achieved from the use of soft magnetic permeable materials for the formation of stator core structures. The geometries of the cores and the dimensions thereof of the stator elements, with relevant tolerances, can be formed without the need to form laminations and therefore can be elaborated to optimize the magnetic potential gradient developed between coupled poles of the permanent rotor magnets and stator electromagnets. An advantage of the present invention is that the poles of each axially placed and separated stator core can be compensated with respect to one another in the axial direction to cancel the effects of the roughing torque without limiting the position relationships between the stator poles in the circumferential direction. A further advantage of the present invention is that the permanent magnets of the rotor, which are arranged in the circumferential and axial directions can be compensated with respect to one another in the axial direction to cancel the effects of the roughing torque without limiting the total number of permanent magnets or their positions in the circumferential direction. The structural features of the invention are incorporated in an engine comprising a rotor and a stator, each placed in an angular ring configuration and separated from the other by an annular radial air space. Preferably, the stator comprises a plurality of separate integral electromagnetic core segments, coaxially positioned about an axis of rotation. Each core segment comprises two or more poles integrally linked together. A winding is formed in the link portion to develop, when energized with current, magnetic poles of opposite polarity in adjacent stator poles. The stator core segments are fixed to a non-ferromagnetic support structure and are distributed in the stator ring without there being any reliable contact between them. Therefore, a core segment having a non-energized winding will not have a flux produced therein by the energization of the winding of another ferromagnetically isolated core segment. However, the non-energized electromagnetic core section will be affected by the flow created by the movement of a permanent magnet of the rotor as it approaches and passes the portion of the air space remaining in front of the stator poles. According to one aspect of the present invention, each of the core segments comprises a plurality of poles integrally joined by a link portion that is generally parallel to the axis of rotation. The electromagnetic core segments are preferably formed of powdered metal material. The poles of each stator core segment are offset from each other in the axial direction. The stator poles all have a geometrical configuration of common surface in the air space. The rotor comprises a plurality of permanent magnets with surfaces facing the air space, the surfaces have a common geometric configuration. Each permanent magnet is a magnetic dipole that has a magnetic polarity on the surface that faces the air space and the opposite magnetic polarity on a surface that is far from the air space, thus forming a magnetic polar orientation in a direction perpendicular to the space of air. The permanent magnets have a common surface geometric configuration that can be the same as the stator poles and are aligned in axial rows that are positioned circumferentially along the air space. Each permanent rotor magnet is of a magnetic polarity opposite to the magnetic polarity of the adjacent permanent magnets in its respective ring and axial row. The effect of the pole shift in the axial direction is the significant cancellation of the torsion. Roughing produced at each transition between the rotor magnet and the stator pole, since the transitions in the axially adjacent elements are compensated. The maximum flow connection between the overlapping rotor magnets and the stator poles can be maintained to maximize motorcycling torque capacity. The roughing torque can be compensated by deviating and further configuring the geometric configuration of the stator pole with respect to the axis of rotation. Reference is made to the co-pending application (case number 57357-023) for an additional description of the diversion and pole configuration benefits. A variation of the invention can be executed by compensating the permanent magnets in adjacent rings axially spaced apart in the axial direction. The stator poles of each stator core can be in an axial alignment, since the transitions between the magnets and the stator poles in the axially adjacent elements will deviate by virtue of the positions of the rotor magnet. As a further variation, the poles of the stator core segment may have a geometric configuration of common surface in the air space and the permanent magnet surfaces may have a common geometric configuration different from the geometrical configuration of the stator pole surface . Additional advantages of the present invention will be readily apparent to those skilled in the art from the following detailed description, wherein only the preferred embodiment of the invention is shown and described, simply by way of illustration of the best mode contemplated for carrying out the invention. As can be seen, the invention has the capacity for other and different modalities, and its various details have the capacity to undergo modifications in various obvious aspects, all without departing from the invention. Accordingly, the figures and description will be observed as illustrative in nature, and not as a restriction.

BRIEF DESCRIPTION OF THE FIGURES The present invention is illustrated by way of example, and not by way of limitation, in the accompanying figures and in which like reference numerals refer to like elements and wherein: Figure 1 is an exemplary view showing the elements of rotor and stator of a motor as described in copending application 09 / 826,422. Figure 2 is a partial planar display of elements of Figure 1 illustrating relative positions of the stator pole surfaces and rotor surfaces for three instants of time during engine operation. Figure 3 illustrates a three-dimensional parts view of an engine as described in the co-pending application (case number 57357-019). Figure 4 is a partial planar display of the permanent magnet surfaces of the rotor and the stator pole of a motor, such as that shown in Figure 3. Figure 5 is a partial planar display of the permanent magnet surfaces. of the rotor and pole of the stator of an engine according to the present invention. Figure 6 is a partial planar display of the permanent magnet surfaces of the rotor and the stator pole of a motor according to another aspect of the present invention. Fig. 7 is a partial planar display of the permanent magnet surfaces of the rotor and stator pole of a motor according to the present invention and a variation of the arrangement of Fig. 6.

DETAILED DESCRIPTION OF THE INVENTION The concepts of the present invention apply to motors having two or more sets of axially spaced rotor and stator elements. For the purpose of understanding the structural interrelationship between the stator and rotor elements, Figure 3 illustrates a three-dimensional parts view of an engine, such as that described in the copending application (case number 57357-019). The motor 15 comprises an annular permanent magnet rotor 20 and an annular stator structure 30 separated by a radial air space. A plurality of electromagnetically insulated stator core segment elements 36, made of magnetically permeable material, are supported by a supporting structure 50 which maintains the frogromagnetic isolation of the segments. Segment 36 is an integral structure formed of a magnetically permeable material with pole surfaces 32 facing the air space. The pole surfaces of each core segment may have different surface areas, as shown, or they may have an identical surface configuration. Each stator core element 36 is an electromagnet that includes windings 38 formed in the core material. The reversal of the direction of the wind current, in a known manner, effects the reversal of the magnetic polarities of each of the poles. The rotor comprises a permanent magnet section 21 with three axially spaced apart rings of rotor magnets 22-24, circumferentially distributed around the air space, and a rear iron ring 25 on which the permanent magnets are mounted. The support structure of the stator 50 can be fixed to a stationary axis, with the rotor mounted inside a housing that is hinged to the shaft through suitable bearings and bearings. Figure 4 is a partial planar display of the permanent magnet surfaces of the rotor and the stator pole of a motor, such as that shown in Figure 3, taken with the rotor at rest. The upper portion of the figure shows four adjacent stator elements 36, each comprising three stator poles having surfaces 32. The lower portion of the figure shows portions of three axially spaced rotor rings having magnets 21. The stator elements and rotor, which in real construction are placed circumferentially around the axis of rotation, are placed on the flat horizontal surface to illustrate their spatial relationships through the air space, represented by the horizontal space that exists in between. The axis of rotation is in the vertical direction. In actual construction, the upper row of the stator poles is aligned through the air space with the bottom row of the rotor magnets, the center row of the stator poles is aligned through the air space with the center row of rotor magnets, and the lower row of stator poles is aligned through air space with the upper row of the rotor magnets. When the motor is in drive operation, the roughing torque occurs in each of the aligned rows of stator poles and rotor magnets, in the manner discussed above and illustrated in Figure 2. Because all the stator poles in each segment are in axial alignment with each other and the adjacent rotor magnets in each separate ring of magnets are in axial alignment with each other, the corresponding rows of stator poles and rotor magnets produce the same torsional variations of roughing and are additives. Figure 5 is a partial planar display of permanent magnet surfaces of the rotor and stator poles of a motor according to the present invention. The support structure for the elements shown can be similar to that shown in Figure 3. The stator segments 36 are aligned in the direction of the axis of rotation and are placed in a circle around the surface. of the axis of rotation.

All the stator poles in each segment are in axial alignment with each other. In this illustration, all surfaces of the stator poles have the same geometric configuration and dimensions. The axially spaced rotor rings 22-24 are also placed closely together about the axis of rotation. As shown, all magnet surfaces have the same geometric configuration and dimensions. However, the magnets in adjacent rings are offset from one another in the axial direction. During the operation of the motor, the rotor traverses a horizontal path with respect to the stationary stator segments. The alignment transition points between the rotor magnets and the stator poles of a corresponding stator pole / rotor ring assembly occur at the positions along the circumference and at the moments that are different from each other. The other sets of rotor and stator elements correspond teeth. Therefore, although each assembly produces a variant roughing torque in a similar time, the roughing torques are deviated from each other in relation to the deviation of the rotor magnets. The roughing torques, to a variable degree cancel each other, so that the effect of the combined roughing torque can be minimal. The dimensions of the stator poles of each core segment and / or the dimensions of the rotor magnets do not have to be identical but may vary as shown, for example, in the arrangement of Figure 3. The degree of Deviation can be selected appropriately for an optimum effect in consideration of the dimensional characteristics. Figure 6 is a partial planar display of the permanent magnet surfaces of the rotor and stator pole of a motor, according to another aspect of the present invention. The support structure for the elements shown may be similar to that shown in Figure 3. The rotor 21 comprises three sets of axially spaced permanent magnet rings 22-24. The magnets in adjacent rings have substantially the same surface dimensions and are in axial alignment with each other. The stator segments 36 are aligned in the direction of the axis of rotation and are positioned circumferentially about the axis of rotation. However, the stator poles in each segment are deviated from each other in the axial direction. The deviated positions of the pole surfaces with respect to the substantially aligned base portions of the segment can be formed from a soft, magnetically permeable medium such as powdered metal materials which can be molded to the shape of seada. As in the arrangement of Figure 5, during the operation of the motor, the rotor traverses a horizontal path with respect to the stationary stator segments. The alignment transition points between the rotor magnets and the stator poles of a corresponding stator pole / rotor ring assembly occur at positions along the circumference and at times that are different from the transition points at each one of the other sets of corresponding rotor and stator elements. Each set produces a variant roughing torque in similar time but deviated from the others depending on the deviation of the stator poles. The dimensions of the stator poles of each core segment can differ from each other, as can the dimensions of the surfaces of the rotor magnets. The degree of deviation can be selected appropriately for optimal cancellation of the combined roughing torques. Fig. 7 is a partial planar display of the permanent magnet surfaces of the rotor and stator pole of a motor, according to the present invention and a variation of the arrangement of Fig. 6. The rotor magnets in the adjacent rings 22 -24 have substantially the same surface dimensions and are in axial alignment with each other. The stator poles of each stator segment 36 are aligned with each other and with the base support portion of the core. Nevertheless, the stator segments 36 are offset with respect to the axis of rotation. The displacement caused by a specific deflection angle of the stator segment from the axis changes the alignment transition points between the rotor magnets and the stator poles of a corresponding stator pole / rotor ring assembly, from the transition points in each of the other sets of corresponding rotor and stator elements, such as in the arrangement of Figure 6. In operation, as in the previously described variations of the invention, the three sets of rotor elements and Stator have substantially the same configurations such that each group produces a roughing torque of variation in similar time. As the roughing torsions produced by the individual assemblies are deviated from each other depending on the deviation of the poles of the stator segments incident to the deviation ratio, the roughing torques to some degree cancel each other out. In addition, the roughing torque produced by each of the assemblies is reduced by virtue of the deviated relationship between the stator poles and the corresponding rotor magnets. The leading edge of a magnet approaching a stator pole through the air gap will not overlap the entire edge of the stator pole immediately, since the edges are out of the relationship parallel to each other by an angle of deflection of the pole of the stator. Therefore, the change in the roughing torque at the transition points when a rotor magnet approaches the overlap ratio with a stator pole through the air space is more gradual than the torsional change in the arrangements previously analyzed. Therefore, the oscillations of the roughing torque are reduced. Reference is made to copending application 10 / 160,257 for a more detailed explanation of the desirable effects of a diverted provision. The embodiment of Figure 7 provides the benefits of changed and deviated relationships between the rotor and stator elements. Similar effects can be obtained from the variations where the stator poles of each segment are aligned in the axial direction and the rotor magnets are changed as well as deviated with respect to the stator poles. In this description, only the preferred embodiments of the invention and only a few examples of its versatility are shown and described. It will be understood that the invention can be used in other combinations and environments and also has the ability to undergo changes or modifications within the scope of the inventive concept, as expressed in the present invention. For example, each of the displays illustrated in the figures can be implemented with unitary stator cores instead of segmented ones, which are axially separated from each other with beneficial results. Although specific geometric configurations of the stator core elements have been illustrated, it should be recognized that the inventive concept in the present invention encompasses a multitude of variations of these configurations since virtually virtually any shape can be configured using powdered metal technology. Therefore, a specific core configuration can be adapted to the desired flow distribution. Although the description of the present invention shows the stator surrounded by the rotor, the concepts of the invention also apply to motors where the rotors are surrounded by stators.

Claims (18)

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as a priority: CLAIMS

1. - A rotating permanent magnet electric motor comprising: a stator comprising a plurality of segments of electromagnetic core, fer romagnatically insulated, separated and placed coaxially about an axis of rotation to form an annular cylindrical stator ring, each of the core segments comprise a plurality of poles integrally joined by a link portion extending generally in the direction of the axis of rotation; and a cylindrical annular rotor concentric with the stator and separated therefrom by an annular cylindrical air space, said rotor comprises a plurality of permanent magnets having surfaces facing the air space and forming axially spaced rings of separate magnets placed in circumference Along the air space, the number of said rings is equal in number to the number of stator poles in a stator core segment; wherein the poles of each stator core segment are offset from each other in the axial direction.

2. - The rotating permanent magnet electric motor according to claim 1, characterized in that the plurality of permanent magnets of the rotor are aligned in axial rows placed circumferentially along the air space.

3. - The rotating permanent magnet electric motor according to claim 2, characterized in that the poles of the stator core segments and the permanent magnets of the rotor have a common geometrical configuration in their air space surfaces.

4. - The rotating permanent magnet electric motor according to claim 1, characterized in that the core segments of the stator are fixed to a non-frogmagnetic support structure and distributed in the stator ring without ferromagnetic contact between yes.

5. - The rotating permanent magnet electric motor according to claim 2, characterized in that a winding is formed in the link portion to develop, when energized with current, magnetic poles of opposite polarity in the adjacent stator poles.

6. - The rotating permanent magnet electric motor according to claim 5, characterized in that each permanent rotor magnet is of a magnetic polarity opposite to the magnetic polarity of the adjacent permanent magnets in its respective ring and axial row.

7. - The rotating permanent magnet electric motor according to claim 6, characterized in that each permanent magnet is a magnetic dipole having a magnetic polarity on the surface that faces the air space and the opposite magnetic polarity on a surface that it is far from the air space, thus forming a magnetic polar orientation in a direction perpendicular to the air space.

8. - The rotating permanent magnet electric motor according to claim 1, characterized in that the electromagnetic core segments are formed of powdered metallic material.

9. - The rotating permanent magnet electric motor according to claim 2, characterized in that the poles of the stator core segment have a geometric configuration of common surface in the air space and the permanent magnet surfaces have a common geometric configuration different from the geometrical configuration of the surface of the stator pole.

10. - The rotary electric motor according to claim 1, characterized in that each stator pole has a geometrical surface configuration that is offset with respect to the axis of rotation.

11. - A rotating permanent magnet electric motor comprising: a stator comprising a plurality of electromagnetic core segments, ferromagnetically isolated, separated and placed coaxially about an axis of rotation to form a cylindrical stator ring, each of which Core segments comprise a plurality of poles integrally joined by a link portion extending generally in the direction of the axis of rotation; and a cylindrical annular rotor concentric with the stator and separated therefrom by a cylindrical annular air space, said rotor comprises a plurality of permanent magnets having surfaces facing the air space and forming axially spaced rings of separate magnets positioned circumferentially along the air space, the number of said rings is equal in number to the number of stator poles in a stator core segment; wherein the permanent magnets in adjacent rings are offset from each other in the axial direction.

12. - The rotating permanent magnet electric motor according to claim 11, characterized in that the stator poles of each core segment are aligned in the axial direction.

13. - The rotating permanent magnet electric motor according to claim 11, characterized in that the electromagnetic core segments are formed of pol-metal material.

14. - The rotating permanent magnet electric motor according to claim 13, characterized in that the poles of the stator core segment have a geometric configuration of common surface in the air space and the permanent magnet surfaces have a common geometric configuration different from the geometrical configuration of the surface of the stator pole.

15. - A rotating permanent magnet electric motor comprising a plurality of axially spaced sets of corresponding stator and rotor elements, wherein each set comprises an annular stator ring having poles circumferentially positioned about an axis of rotation and a rotor annular cylindrical having a plurality of permanent magnets positioned circumferentially along an annular air space opposite the stator poles; and the poles of the adjacent stator assemblies are offset from each other in the axial direction.

16. - The rotating permanent magnet electric motor according to claim 15, characterized in that the permanent magnets of the adjacent rotor element assemblies are aligned in the axial direction.

17. - A rotating permanent magnet electric motor comprising a plurality of axially spaced sets of corresponding stator and rotor elements, wherein each set comprises an annular stator ring having poles circumferentially disposed about an axis of rotation and a cylindrical annular rotor having a plurality of permanent magnets positioned circumferentially along an annular air gap opposite the stator poles; and the permanent magnets of the adjacent rotor element assemblies are offset from each other in the axial direction.

18. - The rotating permanent magnet electric motor according to claim 17, characterized in that the stator poles of the adjacent stator assemblies are aligned in the axial direction.