CN108736609B

CN108736609B - Magnetic pole module, motor rotor and method for manufacturing motor rotor

Info

Publication number: CN108736609B
Application number: CN201810845193.9A
Authority: CN
Inventors: 宋佺; 孙杨
Original assignee: Beijing Goldwind Science and Creation Windpower Equipment Co Ltd
Current assignee: Beijing Goldwind Science and Creation Windpower Equipment Co Ltd
Priority date: 2018-07-27
Filing date: 2018-07-27
Publication date: 2020-02-28
Anticipated expiration: 2038-07-27
Also published as: CN108736609A

Abstract

The invention relates to a magnetic pole module, a motor rotor and a method for manufacturing the motor rotor. An electric machine rotor (3000) comprising a rotor yoke (350) and a plurality of pole modules (300) arranged on the rotor yoke (350), each pole module (300) comprising a base plate (310), a cover casing (340) and a pair of pole units (320, 330) of opposite polarity accommodated in an accommodation space formed by the base plate (310) and the cover casing (340), wherein a pair of pole units (320, 330) within each pole module (300) are spaced apart from each other by a first distance along a circumferential direction of the rotor yoke (350) and different circumferentially adjacent pole modules (300) are spaced apart from each other by a second distance along the circumferential direction of the rotor yoke (350), wherein the first distance and the second distance are different. The motor rotor provided by the invention can give consideration to the performances of a generator (cogging torque and torque ripple), the protection of a magnetic pole and the mechanical fixation of the magnetic pole.

Description

Magnetic pole module, motor rotor and method for manufacturing motor rotor

Technical Field

The present invention relates to the field of electrical machines, and more particularly to a pole module, an electrical machine rotor comprising the pole module and a method of manufacturing the electrical machine rotor.

Background

For a permanent magnet direct drive generator of a large wind generating set, two important design indexes are that the cogging torque and the torque ripple of the generator are reduced. The smaller the cogging torque of the generator is, the lower the cut-in wind speed of the wind generating set is, the rotating speed running range of the set is expanded, and the wind energy utilization rate and the generating capacity of the set are improved. The smaller the torque pulsation of the generator is, the higher the operation stability of the wind turbine generator system is, and the longer the service life of rotating parts such as bearings is.

In order to reduce the cogging torque and the torque ripple of the generator, a common solution in the design of the motor at present is to use a stator skewed slot mode or a rotor skewed pole mode for the motor. If the skewed slot mode of the motor stator is adopted, the coil is difficult to manufacture due to the problems of skewed slot angles and the like, the length of the coil is increased, the resistance of a winding is increased, the copper loss of the motor is increased, and the heat is increased. For the motor rotor oblique pole mode, referring to fig. 1, if a mode of axially inclining each magnetic pole on the rotor yoke is adopted, each magnetic pole 1 on the rotor yoke 2 needs to be axially inclined along the motor, which means that the magnetic pole 1 or the rotor yoke 2 needs to be made into a special shape (i.e. other shapes except for a conventional magnetic pole shape such as a rectangular parallelepiped), which not only increases the manufacturing difficulty of the magnetic pole 1 or the rotor yoke 2, but also increases the processing and manufacturing difficulty of a required mold and a required tool when the magnetic pole 1 is produced and assembled, greatly reduces the yield of the magnetic pole 1 or the rotor yoke 2, and leads to increase of the product cost. In addition, referring to fig. 2, the motor rotor skewed pole manner may also be to stagger a plurality of sections of conventional magnetic poles 11 in the axial direction of the motor by a certain angle (i.e., a segmented skewed pole) along the axial direction, but this puts a strict requirement on the dimensional control precision when the magnetic poles 11 are assembled, which reduces the yield and assembly efficiency of the magnetic poles 11, and further reduces the production efficiency.

In addition, it is particularly important that the operating conditions of the wind generating set are complicated and variable, and the design life of the generator usually requires 20 years or even 25 years, which requires the fixing and protection process of the rotor magnetic pole to provide higher mechanical fatigue resistance and corrosion resistance. The fixing mode of the rotor magnetic pole mainly comprises a surface mounting mode and an insertion mode. The surface-mounted magnetic pole fixing process is to fix the magnetic pole on the surface of the rotor magnetic yoke by resin bonding. In the surface-mounted magnetic pole fixing process, because the magnetic poles are completely fixed on the surface of a magnetic yoke of the rotor through resin bonding force, once a sealing weak point occurs in the process of executing the process, under the condition of long-time high-temperature and high-humidity operation of the wind generating set, the magnetic poles are easy to rust and pulverize due to insufficient sealing, so that the sticking failure of the resin to the magnetic poles is caused, and finally the rusted magnetic poles are separated from the rotor to generate the jumping phenomenon under the action of mutual repulsion force between the magnetic poles, so that the abrasion of the stator and the rotor and the tower accident caused by. The plug-in magnetic pole fixing process is characterized in that a magnetic pole is inserted into a groove in a rotor core, and the two axial ends of the magnetic pole are fixed through end plates, so that the magnetic pole is fixed. Although the plug-in type magnetic pole fixing process realizes reliable fixation of the magnetic pole through the slot fixing type structure, the hidden trouble of insufficient magnetic pole sealing still exists, and the magnetic pole is easy to rust and pulverize under the long-time high-temperature and high-humidity operation condition of the wind generating set, so that the excitation magnetic flux of the rotor magnetic pole and the air gap magnetic induction intensity of the generator are weakened, and the generating capacity of the wind generating set is further reduced.

Disclosure of Invention

To solve the above problems in the prior art, according to an aspect of the present invention, there is provided a magnetic pole module capable of achieving good sealing and protection of a magnetic pole or a magnetic pole unit and easy mechanical fixing.

According to another aspect of the present invention, a rotor of an electric machine with a pole-offset feature is provided that combines generator performance (cogging torque, torque ripple), pole shielding, and mechanical fixation of the poles.

According to another aspect of the present invention, there is provided a method of manufacturing a rotor for an electrical machine as described above.

According to one aspect of the invention, a pole module comprises: a substrate; a first magnetic pole unit and a second magnetic pole unit disposed on the front surface of the substrate, the first magnetic pole unit and the second magnetic pole unit having opposite polarities; and the cover is buckled on the first magnetic pole unit, the second magnetic pole unit and the base plate, and comprises a first part for covering the first magnetic pole unit and a second part for covering the second magnetic pole unit, and the first part and the second part are spaced from each other.

Optionally, the enclosure may further comprise a third portion located between the first and second portions and recessed toward the substrate relative to the first and second portions.

Alternatively, the depth of the third partial recess may be less than or equal to the thickness of the first and second magnetic pole units.

Alternatively, each gap between the cover, the substrate, the first magnetic pole unit, and the second magnetic pole unit may be filled with resin.

Alternatively, the middle portion of the substrate may be provided with one or more substrate through-holes, and the third portion of the cover may be provided with one or more cover through-holes corresponding to the one or more substrate through-holes.

Alternatively, the first and second magnetic pole units may be spaced apart from each other in a width direction, one side surface of the first magnetic pole unit in the width direction may be aligned with the first side surface of the substrate, and one side surface of the second magnetic pole unit in the width direction may be aligned with the second side surface of the substrate.

Alternatively, the first and second magnetic pole units may be spaced apart from each other in the width direction, each magnetic pole unit may include a plurality of magnetic poles aligned in the length direction, and the plurality of magnetic poles in each magnetic pole unit may have the same polarity.

According to another aspect of the present invention, an electric machine rotor may include a rotor yoke and a plurality of magnetic pole modules disposed on the rotor yoke, each of the magnetic pole modules including a base plate, a cover case, and a pair of magnetic pole units of opposite polarities accommodated in an accommodation space formed by the base plate and the cover case, wherein a pair of magnetic pole units within each of the magnetic pole modules is spaced apart from each other by a first distance along a circumferential direction of the rotor yoke, and different magnetic pole modules circumferentially adjacent thereto are spaced apart from each other by a second distance along the circumferential direction of the rotor yoke, wherein the first distance and the second distance may be different.

Alternatively, a pair of magnetic pole units may be disposed on the base plate along the circumferential direction, each magnetic pole unit may include a plurality of magnetic poles aligned in the axial direction, and the plurality of magnetic poles in each magnetic pole unit may have the same polarity.

Alternatively, the cover may include first and second portions for covering each of the pair of pole units, respectively, and a third portion between the first and second portions to separate the first and second portions.

Alternatively, the third portion may be recessed toward the substrate with respect to the first and second portions, and the recessed depth may be less than or equal to the thickness of the pair of pole units.

Alternatively, each gap between the cover, the base plate, and the pair of magnetic pole units may be filled with resin.

Alternatively, one or more substrate through-holes may be provided in the middle of the substrate, one or more case through-holes corresponding to the one or more substrate through-holes may be provided in the third portion of the case, screw holes may be provided in the rotor yoke, and the one or more substrate through-holes, the one or more case through-holes, the screw holes may be aligned with each other, and the magnetic pole module may be fixed to the rotor yoke by a fastener.

Alternatively, the plurality of magnetic pole modules may be arranged on the rotor yoke in a row along a circumferential direction of the rotor yoke, each of the magnetic pole modules in the row may be aligned with each other in the circumferential direction of the rotor yoke, and the plurality of magnetic pole modules may be arranged on the rotor yoke in a column along an axial direction parallel to a central rotational axis of the electric machine rotor, each of the magnetic pole modules in the column may be aligned with each other in the axial direction parallel to the central rotational axis of the electric machine rotor.

Alternatively, the polarities of circumferentially adjacent pole units in different pole modules may be opposite and the polarities of axially adjacent pole units in different pole modules may be the same.

According to another aspect of the present invention, a method of manufacturing a rotor of an electric machine includes: arranging a pair of magnetic pole units with opposite polarities on the substrate in parallel; buckling a cover on the pair of magnetic pole units and the substrate, so that a first part and a second part of the cover which are spaced apart cover each of the pair of magnetic pole units respectively, and the pair of magnetic pole units are spaced apart by a first distance; pouring resin into an accommodating space formed by the cover and the substrate, thereby forming a magnetic pole module; the plurality of pole modules are arranged on the rotor yoke such that different circumferentially adjacent pole modules are spaced apart from each other by a second distance along a circumferential direction of the rotor yoke, the first distance being different from the second distance.

Optionally, the method may further comprise: when the cover is fastened, a third portion located between the first portion and the second portion of the cover and recessed toward the substrate with respect to the first portion and the second portion covers a middle portion of the substrate.

Alternatively, before the housing is fastened, an adhesive may be applied to the front surface of each of the pair of pole units for adhering the front surface to the housing; after the cover is buckled on the pair of magnetic pole units, the front surfaces of the cover and the pair of magnetic pole units are pressed to completely spread the adhesive between the cover and the front surfaces of the pair of magnetic pole units; and sealing an external joint between the cover shell and the substrate so that the cover shell and the substrate form a sealed space.

Optionally, the housing may further include a vacuum suction nozzle and a glue injection nozzle respectively provided on both end surfaces of the housing, and the method may further include the steps of: and pouring resin into the accommodating space formed by the housing and the substrate through the vacuumizing nozzle and the glue injection nozzle so as to fill each gap between the housing, the substrate and the pair of magnetic pole units with the resin, removing the vacuumizing nozzle and the glue injection nozzle after the resin pouring is finished, and coating a sealant at the position where the glue injection nozzle and the vacuumizing nozzle are removed for sealing.

Optionally, one or more substrate through holes are formed in the substrate, one or more housing through holes are formed in the third portion of the housing, and one or more threaded holes are formed in the rotor yoke, the method may further include the steps of: the pole modules are mechanically fixed to the rotor yoke by passing one or more fasteners through one or more base plate through-holes, one or more cover shell through-holes and one or more threaded holes, respectively, and the polarities of circumferentially adjacent pole units in different pole modules are opposite, the polarities of axially adjacent pole units in different pole modules being the same.

By adopting the magnetic pole module, the magnetic pole or the magnetic pole unit can be effectively and reliably sealed, and the mechanical fixation of the magnetic pole or the magnetic pole unit is facilitated.

By adopting the motor rotor provided by the invention, the cogging torque and the torque ripple of the generator can be reduced, the magnetic poles or the magnetic pole units are reliably fixed on the magnetic yoke of the rotor, and the magnetic poles or the magnetic pole units are reliably sealed, so that the performances of the generator (the cogging torque and the torque ripple), the magnetic pole protection and the mechanical fixation of the magnetic poles are considered.

By adopting the method for manufacturing the motor rotor, the manufacturing working hours of the magnetic pole module can be reduced, the reliable sealing protection and fixation of the magnetic pole can be realized, and meanwhile, a magnetic pole arrangement mode capable of reducing the cogging torque and the torque ripple of the generator is provided.

Drawings

FIG. 1 is a schematic view showing a portion of a prior art electric machine rotor employing a rotor skewed pole approach;

FIG. 2 is a schematic view showing a portion of a prior art electric machine rotor employing a rotor segmented skewed pole approach;

fig. 3 is a schematic view showing the structures of a substrate and a magnetic pole unit of a magnetic pole module according to an embodiment of the present invention;

fig. 4 is a schematic structural view showing a housing of a magnetic pole module according to an embodiment of the present invention;

fig. 5 is a schematic structural view showing a base plate, a magnetic pole unit, and a cover case of a magnetic pole module according to an embodiment of the present invention;

fig. 6 is a schematic structural view showing a magnetic pole module (including a glue injection nozzle and a vacuum suction nozzle) according to an embodiment of the present invention;

fig. 7 is a schematic structural view showing a magnetic pole module (with the glue injection nozzle and the vacuum suction nozzle removed) according to an embodiment of the present invention;

fig. 8 is a schematic structural view illustrating a part of a rotor of a motor according to an embodiment of the present invention.

The reference numbers illustrate:

1-magnetic pole; 2-a magnetic yoke; 11-a magnetic pole; 300-a pole module; 310-a substrate; 311 a-front surface; 311 b-a back surface; 312 a-a first side surface; 312 b-a second side surface; 313 a-a first end surface; 313 b-a second end surface; 315-substrate via; 320-a first pole unit; 321 a-a front surface; 321 b-back surface; 322 a-a first side surface; 322 b-a second side surface; 323 a-first end surface; 323 b-second end surface; 330-a second pole unit; 331 a-front surface; 331 b-back surface; 332 a-a first side surface; 332 b-a second side surface; 333 a-first end surface; 333 b-a second end surface; 340-a housing; 341 a-first portion; 341 b-second portion; 341 c-third portion; 342 a-a first side surface; 342 b-a second side surface; 342 c-a third side surface; 342 d-a fourth side surface; 343 a-a first end surface, 343 b-a second end surface; 345-housing through-hole; 348-vacuum nozzle; 349-glue injection nozzle; 350-rotor yoke; 360-a gasket; 370-a fastener; 3000-motor rotor.

Detailed Description

In order that those skilled in the art will better understand the technical concept of the present invention, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings, in which like reference numerals refer to like parts throughout.

As referred to herein, "axial" refers to an axial direction parallel to the central axis of rotation of the rotor of the machine, "circumferential" refers to a circumferential direction along the direction of rotation of the rotor, and "radial" refers to the radial direction of the machine.

Fig. 3 to 8 show a pole module 300 according to an embodiment of the invention and a motor rotor 3000 comprising the pole module 300. Referring to fig. 3 to 7, the magnetic pole module 300 may mainly include a base plate 310, a pair of magnetic pole units (a first magnetic pole unit 320 and a second magnetic pole unit 330), and a cover 340. The pair of pole units are disposed on the base plate 310 with a predetermined distance therebetween, and the cover 340 covers the pair of

pole units

320 and 330 to seal the pair of

pole units

320 and 330.

A plurality of magnetic pole modules 300 are to be fixed on the surface of the rotor yoke 350, thereby forming the motor rotor 3000. In the following description, for convenience of description, the structure of the pole module 300 will be described with terms indicating directions such as "axial", "circumferential", "radial", and the like.

As shown in fig. 3, the substrate 310 may be a rectangular or square plate having a certain thickness. The substrate 310 may have a front surface 311a and a back surface 311b in a thickness direction. The first and second

magnetic pole units

320 and 330 may be disposed on the front surface 311a of the substrate 310. The substrate 310 may further have first and

second side surfaces

312a and 312b in the width direction and first and

second end surfaces

313a and 313b in the length direction. The substrate 310 may be made of a magnetically conductive material.

The middle portion of the substrate 310 may be provided with one or more substrate through holes 315. As shown in fig. 3, two substrate through holes 315 may be disposed along the length direction of the substrate 310.

The first and second

magnetic pole units

320 and 330 may be disposed at phases of the substrate 310 in a width direction of the substrate 310On both sides such that the first pole unit 320 and the second pole unit 330 are spaced apart by a first distance d₁. The first and second

magnetic pole units

320 and 330 may be disposed at both sides of the substrate through-hole 315.

The first and

second pole units

320 and 330 may be spaced apart from each other in a width direction, each of the first and

second pole units

320 and 330 may include one pole, respectively, and each of the first and

second pole units

320 and 330 may also include a plurality of poles aligned in a length direction, respectively. The plurality of magnetic poles in each magnetic pole unit may have the same polarity. As shown in fig. 3, each magnetic pole unit includes 3 magnetic poles, respectively. The first and second

magnetic pole units

320 and 330 have opposite polarities to constitute a pair of magnetic pole units, for example, the first magnetic pole unit 320 may be an N-pole (i.e., each magnetic pole in the first magnetic pole unit 320 has an N-pole polarity), and the second magnetic pole unit 330 may be an S-pole (i.e., each magnetic pole in the second magnetic pole unit 330 has an S-pole polarity).

As shown in fig. 3, the first magnetic pole unit 320 may have front and

back surfaces

321a and 321b in a thickness direction, first and

second side surfaces

322a and 322b in a width direction, and first and

second end surfaces

323a and 323b in a length direction. The second pole unit 330 may have front and

back surfaces

331a and 331b in a thickness direction, first and

second side surfaces

332a and 332b in a width direction, and first and

second end surfaces

333a and 333b in a length direction.

The back surface 321b of the first pole unit 320 and the back surface 331b of the second pole unit 330 may be adhered to the front surface 311a of the substrate 310 by an adhesive (e.g., a structural adhesive).

In the length direction, both ends of the first and second

magnetic pole units

320 and 330 may be aligned with the substrate 310, that is, the first end surface 323a of the first magnetic pole unit 320 and the first end surface 333a of the second magnetic pole unit 330 may be aligned with the first end surface 313a of the substrate 310, and the second end surface 323b of the first magnetic pole unit 320 and the second end surface 333b of the second magnetic pole unit 330 may be aligned with the second end surface 313b of the substrate 310. However, this arrangement is merely an example, and a case where both ends of the magnetic pole unit and both ends of the substrate are slightly misaligned or shifted from each other may also be considered.

As shown in fig. 4 to 5, the cover 340 may be fastened to the base plate 310, the first pole unit 320, and the second pole unit 330 to hermetically enclose the first pole unit 320 and the second pole unit 330 on the base plate 310.

The cover 340 may include a first portion 341a for covering the first pole unit 320 and a second portion 341b for covering the second pole unit 330, and a third portion 341c between the first portion 341a and the second portion 341 b. The first portion 341a and the second portion 341b may be spaced apart from each other by the third portion 341.

The third portion 341c may be recessed toward the substrate 310 with respect to the first and

second portions

341a and 341 b. The third portion 341c may be used to cover the middle of the substrate 310.

After the cover 340 is snap-fitted over the first pole unit 320 and the second pole unit 330, the first pole unit 320 and the second pole unit 330 are physically separated by the cover 340. The first portion 341a of the cover 340 forms, with the base plate 310, an accommodation space for accommodating the first pole unit 320, in which the first pole unit 320 is accommodated and sealed. The second portion 341b of the cover case 340 forms an accommodation space for accommodating the second pole unit 330 with the base plate 310, and the second pole unit 330 is accommodated and sealed in the accommodation space. Further, the third portion 341c of the cover 340 covers a portion of the substrate 310 where the first and second

magnetic pole units

320 and 330 are not disposed (the middle portion of the substrate 310 in the drawing). With this structure, the first and

second pole units

320 and 330 are physically separated by the third portion 341c of the cover 340, thereby preventing the first and

second pole units

320 and 330 from moving relative to each other (e.g., due to magnetic field effects) due to long-term operation of the motor.

In order to seal and fix the first and

second pole units

320 and 330 on the base plate 310 and to maintain the compactness of the structure, the cover 340 may have a shape following the outer surface of the structure in which the

pole units

320 and 330 are installed behind the base plate 310 to closely contact the outer surfaces of the first and

second pole units

320 and 330 and the base plate 310.

For example, the first and second

magnetic pole units

320 and 330 may be disposed on opposite sides of the substrate 310 in the width direction of the substrate 310. Preferably, as shown in fig. 3, the first side surface 322a of the first pole unit 320 may be aligned with the first side surface 312a of the substrate 310, and the second side surface 332b of the second pole unit 330 may be aligned with the second side surface 312b of the substrate 310. The second side surface 322b of the first pole unit 320 may be spaced apart from the first side surface 332a of the second pole unit 330 by a distance. Correspondingly, the cover 340 may have a "concave" shape. The cover case 340 may include first, second, third, and

fourth side surfaces

342a, 342b, 342c, and 342d and first and

second end surfaces

343a and 343b that are in contact with the side surfaces and end surfaces of the first and

second pole units

320 and 330 and the substrate 310, respectively (e.g., by an adhesive) along the width direction and the length direction.

One side of the cover 340 may be open to provide access to the base plate 310, the first pole unit 320, and the second pole unit 330. Therefore, after the cover case 340 covers the first and second

magnetic pole units

320 and 330 and the substrate 310, the first and second

magnetic pole units

320 and 330 are entirely sealed in the cover case 340 (in the first and

second portions

341a and 341b of the cover case 340, respectively), and the side surfaces, the end surfaces, of the substrate 310 are also covered, exposing only the back surface 311b of the substrate 310.

When the cover 340 is fastened to the base plate 310, the first pole unit 320, and the second pole unit 330, the inner surface of the cover 340 may be closely contacted and adhesively fixed to the first pole unit 320, the second pole unit 330, and the base plate 310 by an adhesive.

The close contact and the firm coupling of the first and

second pole units

320 and 330 with the cover case 340 may be ensured by the following method: an adhesive may be applied (e.g., by dispensing or by applying a layer of adhesive with a glue line) to the front surface 321a of the first pole unit 320 and the front surface 331a of the second pole unit 330 before the cover 340 is snapped. Thereafter, the cover 340 is fastened to the first pole unit 320 and the second pole unit 330 such that the first portion 341a and the second portion 341b of the cover 340 cover the first pole unit 320 and the second pole unit 330, respectively, and the cover 340 and the first pole unit 320 and the second pole unit 330 are compressed, ensuring that the adhesive between the inner surface of the cover 340 and the positive surfaces of the first pole unit 320 and the second pole unit 330 is completely spread out, thereby sufficiently filling the gap between the cover 340 and the first pole unit 320 and the second pole unit 330 and preventing the occurrence of air pockets therebetween. Thereafter, the adhesive is cured by heating.

In order to minimize the effect on the air gap between the rotor and the stator, the cover 340 should be closely attached to the front surfaces of the first pole unit 320 and the second pole unit 330, and a glue layer (e.g., an adhesive layer) is applied (e.g., by coating an adhesive) and spread closely against the cover 340 to ensure that the space is filled 100% without the occurrence of voids when resin is vacuum-poured (as will be described in more detail below) due to the small gap.

In addition, the third portion 341c of the cover 340 may be recessed toward the substrate 310 with respect to the first and

second portions

341a and 341b, and the recessed depth may be less than or equal to the thickness of the first and second

magnetic pole units

320 and 330. Based on this, when the cover 340 is fastened, the third portion 341c of the cover 340 may cover the middle of the substrate 310 without contacting the middle of the substrate 310, so that there is a certain gap between the cover 340 and the substrate 310, so that the receiving space formed by the first portion 341a of the cover 340 and the substrate 310 and the receiving space formed by the second portion 341b and the substrate 310 may be communicated for resin infusion (described in detail below) to be performed later.

After the cover case 340 is fastened, the outer joint of the cover case 340 and the base plate 310 may be sealed with a sealant, thereby forming a sealed space between the cover case 340 and the base plate 310 to accommodate the first and

second pole units

320 and 330.

The housing 340 may also include a glue injection nozzle 349 and a vacuum nozzle 348 disposed on both end surfaces of the housing 340. As shown in fig. 4, the glue injection nozzle 349 may be disposed on a first end surface 343a of the housing 340 and the vacuum nozzle 348 may be disposed on a second end surface 343b of the housing 340. The glue injection nozzle 349 and the vacuum nozzle 348 may be provided to vacuum-impregnate the resin into the sealed space formed by the cover 340 and the substrate 310, thereby filling all gaps between the cover 340 and the substrate 310 and between the cover 340 and the first and

second pole units

320 and 330. Since the accommodating space formed by the first portion 341a of the cover 340 and the substrate 310 and the accommodating space formed by the second portion 341b and the substrate 310 are communicated, a set of the glue injection nozzle 349 and the vacuum nozzle 348 may be provided. If the accommodating space is not communicated, at least two sets of glue injection nozzles 349 and vacuum pumping nozzles 348 are also arranged, so that complete glue injection is performed on the accommodating space formed by the cover 340 and the substrate 310.

The gaps between the cover 340 and the side and end surfaces of the

pole units

320 and 330, and between the cover 340 and the outer surface of the base plate 310 can be designed to be large (because the air gap is not affected), thereby ensuring that the resin fills 100% of the gaps at the positions during vacuum infusion.

After the vacuum infusion of resin is completed for the pole module 300, the glue injection nozzle 349 and the vacuum extraction nozzle 348 may be removed. After the glue injection nozzle 349 and the vacuum nozzle 348 are removed, a sealant is applied to the position where the glue injection nozzle 349 and the vacuum nozzle 348 are removed for sealing, for example, the sealant can be used to seal the exposed glue injection port and the vacuum nozzle. As shown in fig. 7, after the pole module 300 is manufactured, the glue injection nozzle 349 and the vacuum suction nozzle 348 are cut off and ground flat, so that the end surface of the cover 340 is flat.

The third portion 341c of the cover 340 may be provided with one or more cover through holes 345 corresponding to the one or more substrate through holes 315 described above. When the cover 340 is snap-fit onto the base plate 310, the first pole unit 320, and the second pole unit 330, one or more cover through holes 345 on the cover 340 are aligned one-to-one with one or more base plate through holes 315 on the base plate 310.

The substrate through-hole 315 and the housing through-hole 345 may be formed when the substrate 310 and the housing 340 are manufactured, respectively, and after the housing 340 is snap-fitted to the substrate 310 and the

magnetic pole units

320 and 330, in vacuum resin injection of a sealed space formed by the housing 340 and the substrate 310, in order to prevent the substrate through-hole 315 and the housing through-hole 345 from affecting the formation of the sealed space and to prevent the substrate through-hole 315 and the housing through-hole 345 from being blocked by the injected resin, a magnetic pole module (unfinished) may be mounted on a specific tool to set the substrate through-hole 315 and the housing through-hole 345 to a specific part of the tool, temporarily blocking the substrate through-hole 315 and the housing through-hole 345, thereby forming the sealed space by the substrate 310 and the housing 340, and then performing a subsequent vacuum-pumping and. Further, alternatively, after the cover 340 is snap-fitted on the substrate 310 and the

pole units

320 and 330, a sealant may be used to seal a joint between the cover through-hole 345 and the substrate through-hole 315, thereby forming a sealed space between the substrate 310 and the cover 340.

Further, although it is described above with reference to the drawings that the substrate through-hole 315 and the housing through-hole 345 may be formed when the substrate 310 and the housing 340 are manufactured, respectively, it is not limited thereto. It is also possible to form the base plate 310 and the cover 340 without through-holes first and then open the through-holes in the magnetic pole module 300 after the resin infusion is completed.

The cover 340 may be made of a non-magnetic material. The outer joints between the edges of the cover 340 and the edges of the substrate 310, and between the cover through-holes 345 and the substrate through-holes 315 are sealed by applying a sealant by adhering the pole units (poles) to the substrate 310 made of a magnetically conductive material, applying an adhesive and covering the cover 340 of the magnetically conductive material. And the sealing space formed by the cover 340 and the base plate 310 and accommodating the magnetic pole unit is vacuum-impregnated with resin, so that the magnetic pole can be effectively sealed and protected.

The motor rotor 3000 may be formed by mounting the above-described magnetic pole module 300 on the inner surface of the rotor yoke 350. Fig. 8 shows a schematic structural view of a part of a motor rotor 3000 according to an embodiment of the present invention. As shown in fig. 8, the motor rotor 3000 may include a rotor yoke 350 and a plurality of pole modules 300 disposed on the rotor yoke 350, and the back surfaces 311b of the base plates 310 of the pole modules 300 may contact the radially inner surface of the rotor yoke 350.

Rotor yoke 350 may be provided with a plurality of threaded holes (not visible). The plurality of threaded holes in the rotor yoke 350 may correspond to one or more substrate through holes 315 in the substrate 310 and one or more cover piece through holes 345 in the cover piece 340 of the pole module 300 and be aligned with one another one-to-one when the pole module 300 is mounted on the rotor yoke 350 such that fasteners 370 (which may be provided with spacers 360) pass through the respective substrate through holes 315, cover piece through holes 345, and threaded holes in the rotor yoke 350 to mechanically secure the pole module 300 to the rotor yoke 350.

As shown in fig. 8, the plurality of magnetic pole modules 300 may be disposed on the rotor yoke 350 in a row along an axial direction (i.e., an axial direction) parallel to the central rotational axis of the motor rotor 3000, each magnetic pole module 300 of the row of magnetic pole modules 300 is aligned with each other in the axial direction (i.e., the axial direction) parallel to the central rotational axis of the motor rotor 3000, and the first magnetic pole unit 320 and the second magnetic pole unit 330 of each magnetic pole module 300 are respectively aligned with each other in the axial direction. Axially adjacent pole units in different pole modules are of the same polarity, i.e. pole units of the same polarity are aligned in the axial direction. As shown in fig. 8, the pole modules 300 in the row are arranged vertically in the axial direction as a whole, and the pole modules 300 are not offset or inclined from each other.

Further, the plurality of magnetic pole modules 300 may be arranged on the rotor yoke 350 in a row along a circumferential direction (i.e., circumferential direction) of the rotor yoke 350, each magnetic pole module 300 of the row of magnetic pole modules 300 is aligned with each other in the circumferential direction (i.e., circumferential direction) of the rotor yoke 350, and the first magnetic pole unit 320 of each magnetic pole module 300 is adjacent to the second magnetic pole unit 330 of the adjacent magnetic pole module 300. Circumferentially adjacent pole units in the same pole module or in different pole modules have opposite polarities, i.e., pole units having different polarities are alternately arranged in the circumferential direction. For example, as described above, when the polarity of the first magnetic pole unit 320 in one magnetic pole module 300 is N and the polarity of the second magnetic pole unit 330 is S, the second magnetic pole unit 330 (having the polarity of S) in the one magnetic pole module 300 in the row of magnetic pole modules 300 is adjacent to the first magnetic pole unit 320 (having the polarity of N) of the adjacent other magnetic pole module 300, that is, a magnetic pole unit arrangement in an alternating N-S-N-S polarity form is formed in the circumferential direction of the rotor yoke 350.

When the magnetic pole modules 300 are disposed on the rotor yoke 350, different magnetic pole modules 300 that are circumferentially adjacent are spaced apart from each other by a second distance d along the circumferential direction of the rotor yoke 350₂. In the case where the first side surface 322a of the first pole unit 320 is aligned with the first side surface 312a of the base plate 310 and the second side surface 332b of the second pole unit 330 is aligned with the second side surface 312b of the base plate 310, the adjacent pole units in the circumferentially adjacent different pole modules 300 are also spaced apart from each other by the second distance d in the circumferential direction of the rotor yoke 350₂。

Therefore, the two rows of pole units (the first pole unit 320 and the second pole unit 330) in one pole module 300 are separated by a first distance d₁And the two adjacent rows of the magnetic pole units in two adjacent magnetic pole modules 300 are separated by a second distance d₂And d is₁Is not equal to d₂. In this embodiment, d₁>d₂。

Therefore, in the magnetic pole distribution of the rotor of the electric machine according to the embodiment of the present invention, all the magnetic pole units on the rotor yoke are not equally distributed, but the pitch between each pair of magnetic pole units (i.e., a pair of magnetic pole units in one magnetic pole module) is equal, and the distance of each magnetic pole unit from the adjacent magnetic pole unit is unequal. By adopting the magnetic pole offset structure type, the cogging torque and the torque ripple of the permanent magnet direct drive generator can be reduced.

After the plurality of magnetic pole modules 300 are completely assembled, resin vacuum infusion may be performed once on all the magnetic pole modules 300 as a whole to achieve effective glue filling and sealing of the gaps between the magnetic pole modules 300 and the rotor yoke 350, the fasteners 370, the spacers 360, and the gaps among the substrate through holes 315, the housing through holes 345, and the screw holes on the rotor yoke 350.

The electric machine rotor may also include other components (e.g., structural members such as a rotor bracket), and in the present embodiment, only the rotor yoke 350 and the pole modules 300 disposed and secured to the rotor yoke 350 are shown and described for illustrative purposes.

With the pole offset structural style according to the embodiment of the present invention, each pole module 300 is separately manufactured, and each pole module 300 includes a pair of pole units (a first pole unit 320 and a second pole unit 330 having opposite polarities), which is significantly reduced in man-hours compared to the conventional "one pole module includes one base plate, one row of poles, one cover case".

In addition, by adopting the magnetic pole module 300 and the magnetic pole offset structure, the magnetic pole offset can be effectively realized so as to reduce the cogging torque and the torque ripple, and the

magnetic pole units

320 and 330 and the base plate 310, the

magnetic pole units

320 and 330 and the cover casing 340 and the base plate 310 and the cover casing 340 in each magnetic pole module 300 are fully bonded by means of adhesive bonding and vacuum potting resin, so that 100% glue filling of each gap in the magnetic pole module 300 is realized, and the reliable sealing of the magnetic pole is realized.

In addition, the magnetic pole module 300 and the

magnetic pole units

320, 330 are mechanically secured securely by making holes in the base plate 310, the cover 340 and the rotor yoke 350 and by means of fasteners 370 (spacers 360 may be added).

In summary, by adopting the magnetic pole module 300 and the motor rotor 3000, not only can the magnetic pole offset structure be realized, the cogging torque and the torque ripple of the permanent magnet direct drive generator can be effectively reduced, but also the magnetic pole (magnetic pole unit) can be effectively sealed and firmly and mechanically fixed on the rotor magnetic yoke 350, so that the effective sealing of the magnetic pole and the safe and reliable fixing of the magnetic pole module 300 are realized, and the use reliability of the magnetic pole under the working conditions of high temperature and high humidity in the whole life cycle of the generator is ensured. Therefore, the magnetic pole module 300 and the motor rotor 3000 having the magnetic pole offset structural feature including the magnetic pole module 300 according to the present invention have the advantages of the generator performance (cogging torque, torque ripple), the magnetic pole protection and the magnetic pole mechanical fixation.

A method of manufacturing the magnetic pole module 300 and the motor rotor 3000 according to the embodiment of the present invention will be described below with reference to fig. 3 to 8.

First, as shown in fig. 3, a substrate 310 having one or more substrate through holes 315 opened in the middle thereof is manufactured.

Then, a pair of magnetic pole units having opposite polarities, i.e., a first magnetic pole unit 320(N pole) and a second magnetic pole unit 330(S pole), are arranged in parallel on the substrate 310 and at both sides of the substrate through-hole 315 such that the pair of magnetic pole units are spaced apart by a first distance d₁. The first side surface 322a of the first pole unit 320 may be aligned with the first side surface 312a of the substrate 310 and the second side surface 332b of the second pole unit 330 may be aligned with the second side surface 312b of the substrate 310. Meanwhile, the second side surface 322b of the first pole unit 320 is spaced apart from the first side surface 332a of the second pole unit 330 by a first distance d₁. Back surfaces 121b and 331b of the first and second

magnetic pole units

320 and 330 may be adhered to the front surface 311a of the substrate 310 by an adhesive.

In this process, the first and

second pole units

320 and 330 may be temporarily non-magnetic, and after the pole module 300 is finally completed, the pole units may be re-magnetized to prevent the pole units from moving with each other when there is no separator between the first and

second pole units

320 and 330.

Then, as shown in fig. 4 to 5, the cover 340 may be snap-fitted over the base plate 310, the first pole unit 320, and the second pole unit 330, and a sealed space may be formed between the cover 340 and the base plate 310. The first and

second portions

341a and 341b of the cover case 340 may cover the first and

second pole units

320 and 330, respectively, and the third portion 341c of the cover case 340 may cover the middle portion of the substrate 310.

Specifically, before the cover 340 is fastened, an adhesive (for example, spot coating or coating an adhesive by a glue line) may be applied on the front surface 321a of the first pole unit 320 and the front surface 331a of the second pole unit 330 for adhering the

front surfaces

321a and 331a to the cover 340.

The cover case 340 is snap-fitted over the base plate 310, the first pole unit 320, and the second pole unit 330 such that the first portion 341a and the second portion 341b of the cover case 340 cover the first pole unit 320 and the second pole unit 330, respectively, and the third portion 341c of the cover case 340 covers the middle portion of the base plate 310.

After the cover case 340 is fastened to the base plate 310, the first pole unit 320, and the second pole unit 330, the cover case 340 and the first pole unit 320 and the second pole unit 330 may be pressed such that the adhesive between the inner surface of the cover case 340 and the

front surfaces

321a and 331a of the first pole unit 320 and the second pole unit 330 is completely and uniformly spread out, thereby filling the gaps between the cover case 340 and the first pole unit 320 and the second pole unit 330, and heat-curing the adhesive.

After the cover case 340 covers the first and second

magnetic pole units

320 and 330 with the substrate 310, the first and second

magnetic pole units

320 and 330 are entirely sealed in the cover case 340, and the side surfaces, end surfaces of the substrate 310 are also covered, exposing only the back surface of the substrate 310.

Thereafter, the outer joint between the cover case 340 and the base plate 310 may be sealed with a sealant, and then the sealant is cured, whereby the cover case 340 and the base plate 310 form a sealed space for accommodating the

pole units

320, 330.

The housing 340 may further include an evacuation nozzle 348 and a glue injection nozzle 349 respectively disposed on both end surfaces (the first end surface 343a and the second end surface 343b) of the housing 340.

As shown in fig. 6, the pole module 300 of fig. 5 is placed in an upright position with the vacuum nozzle 348 connected to a vacuum line to evacuate the interior of the pole module 300. A glue injection nozzle 349 from the bottom of the axial direction of the cover 340 is connected to a glue injection pipeline, and resin is vacuum-injected into the inside of the sealed space formed by the cover 340 and the substrate 310, so that the resin is completely filled in each gap between the cover 340 and the substrate 310 and between the cover 340 and the

magnetic pole units

320 and 330, and after the vacuum-injection of the resin is completed, the resin is heat-cured.

In this embodiment, the sealing space formed by the cover 340 and the substrate 310 is sealed and filled by vacuum resin infusion, which can ensure that the cover 340 and the

magnetic pole units

320 and 330 are attached to each other when the cover 340 is thin. However, other glue injection methods may be used, for example, if the housing 340 is thick and rigid, a positive pressure glue injection method may be used.

As shown in fig. 7, after the vacuum resin injection is completed, the vacuum nozzle 348 and the glue injection nozzle 349 on the cover 340 may be removed or cut off, then both end surfaces of the cover 340 are polished flat, burrs are removed, and a sealant is applied to the positions where the glue injection nozzle 349 and the vacuum nozzle 348 are removed to perform sealing, for example, the exposed glue injection port and the vacuum injection port may be sealed by using a sealant. The sealant is heat cured to complete the sealing of the magnetic pole module 300.

The magnetic pole units in the magnetic pole module 300 are magnetized such that the first and second

magnetic pole units

320 and 330 in the magnetic pole module 300 are magnetized to have opposite polarities, for example, N-pole and S-pole, respectively, thereby completing the manufacture of the single magnetic pole module 300.

As shown in fig. 8, a plurality of magnetic pole modules 300 are fitted to a rotor yoke 350 having screw holes (not visible in the drawing). The pole modules 300 are positioned by a tool or a robot arm so that the substrate through holes 315 and the housing through holes 345 of the pole modules 300 correspond to the screw holes on the rotor yoke 350 one to one. Mechanical fixation of the pole modules 300 is achieved by mechanically securing the plurality of pole modules 300 to the rotor yoke 350 by passing a plurality of fasteners 370 (which may be provided with spacers 360) through a plurality of substrate through holes 315, a plurality of housing through holes 345, and a plurality of threaded holes in the rotor yoke 350, respectively. After mechanical attachment, the exposed fasteners 370, the spacers 360, the substrate through holes 315, the housing through holes 345, and the threaded holes in the rotor yoke 350 may be knife coated with a sealant and heat cured to seal the locations. Or after the magnetic pole modules 300 are completely assembled, resin vacuum infusion can be sequentially performed on all the magnetic pole modules 300 in sequence, so that the gaps between the magnetic pole modules 300 and the rotor yoke 350, between the fastening members 370, between the gaskets 360 and the threaded holes in the substrate through holes 315, between the housing through holes 345 and in the rotor yoke 350 can be effectively filled with glue and sealed.

As shown in fig. 8, when assembling the magnetic pole modules 300, different magnetic pole modules 300 that are circumferentially adjacent may be spaced apart from each other by a second distance along the circumferential direction of the rotor yoke 350. As described above, at the first side surface 322a of the first pole unit 320 and the first side of the substrate 310With the surfaces 312a aligned and the second side surfaces 332b of the second pole units 330 aligned with the second side surfaces 312b of the base plates 310, adjacent pole units in circumferentially adjacent different pole modules 300 are also spaced apart from each other by a second distance d along the circumferential direction of the rotor yoke 350₂。

Meanwhile, during assembly, it is required to ensure that the polarities of circumferentially adjacent magnetic pole units in different magnetic pole modules are opposite, and the polarities of axially adjacent magnetic pole units in different magnetic pole modules are the same.

While the embodiments of the present invention have been shown and described in detail, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents (e.g., various features of the invention can be combined to arrive at new embodiments). Such combinations, modifications and improvements are intended to be within the scope of the invention.

Claims

1. A pole module (300), characterized in that the pole module (300) comprises:

a substrate (310);

a first magnetic pole unit (320) and a second magnetic pole unit (330) disposed on a front surface (311a) of the substrate (310), the first magnetic pole unit (320) and the second magnetic pole unit (330) having opposite polarities;

a cover case (340) snap-fitted over the first pole unit (320), the second pole unit (330), and the base plate (310), and an outer joint between the cover case (340) and the base plate (310) is sealed such that the first pole unit (320) and the second pole unit (330) are accommodated in a sealed space formed by the cover case (340) and the base plate (310), the cover case (340) including a first portion (341a) for covering the first pole unit (320) and a second portion (341b) for covering the second pole unit (330), the first portion (341a) and the second portion (341b) being spaced apart from each other.

2. The pole module (300) of claim 1 wherein the casing (340) further comprises a third portion (341c) located between the first portion (341a) and the second portion (341b) and recessed toward the substrate (310) relative to the first portion (341a) and the second portion (341 b).

3. The pole module (300) of claim 2, wherein the third portion (341c) is recessed to a depth less than or equal to the thickness of the first pole unit (320) and the second pole unit (330).

4. The pole module (300) of any of claims 1 to 3 wherein each gap between the cover (340), the base plate (310), the first pole unit (320) and the second pole unit (330) is filled with resin.

5. The pole module (300) of claim 2 wherein the central portion of the base plate (310) is provided with one or more base plate through holes (315) and the third portion (341c) of the enclosure (340) is provided with one or more enclosure through holes (345) corresponding to the one or more base plate through holes (315).

6. The magnetic pole module (300) of any of claims 1 to 3, wherein the first magnetic pole unit (320) and the second magnetic pole unit (330) are spaced apart from each other in a width direction, one side surface (322a) of the first magnetic pole unit (320) in the width direction being aligned with the first side surface (312a) of the substrate (310), and one side surface (332b) of the second magnetic pole unit (330) in the width direction being aligned with the second side surface (312b) of the substrate (310).

7. The magnetic pole module (300) of claim 1, wherein the first magnetic pole unit (320) and the second magnetic pole unit (330) are spaced apart from each other in a width direction, each magnetic pole unit comprising a plurality of magnetic poles aligned in a length direction, the plurality of magnetic poles in each magnetic pole unit having the same polarity.

8. An electric machine rotor (3000) characterized in that the electric machine rotor (3000) comprises a rotor yoke (350) and a plurality of pole modules (300) arranged on the rotor yoke (350), each pole module (300) comprising a base plate (310), a cover shell (340) and a pair of pole units (320, 330) of opposite polarity accommodated in an accommodation space formed by the base plate (310) and the cover shell (340), wherein a pair of pole units (320, 330) within each pole module (300) are spaced from each other by a first distance in a circumferential direction of the rotor yoke (350) and different circumferentially adjacent pole modules (300) are spaced from each other by a second distance in the circumferential direction of the rotor yoke (350), wherein the first distance and the second distance are different.

9. The electric machine rotor (3000) of claim 8, wherein said pair of pole units (320, 330) are circumferentially disposed on said base plate (310), each pole unit comprising a plurality of poles aligned in an axial direction, the plurality of poles in each pole unit having the same polarity.

10. The electric machine rotor (3000) of claim 8, wherein said casing (340) comprises a first portion (341a) and a second portion (341b) for covering each of said pair of pole units (320, 330), respectively, and a third portion (341c) located between said first portion (341a) and said second portion (341b) to separate said first portion (341a) from said second portion (341 b).

11. The electric machine rotor (3000) of claim 10, wherein the third portion (341c) is recessed toward the base plate (310) relative to the first portion (341a) and the second portion (341b), the recessed depth being less than or equal to the thickness of the pair of pole units (320, 330).

12. The electric machine rotor (3000) according to any of claims 8 to 11, wherein each gap between the cover casing (340), the base plate (310) and the pair of pole units (320, 330) is filled with resin.

13. The electric machine rotor (3000) of claim 10, wherein one or more substrate through holes (315) are provided in the middle of the substrate (310), one or more housing through holes (345) corresponding to the one or more substrate through holes (315) are provided in the third portion (341c) of the housing (340), threaded holes are provided in the rotor yoke (350), and the one or more substrate through holes (315), the one or more housing through holes (345), the threaded holes are aligned with each other and the pole module (300) is secured to the rotor yoke (350) by fasteners (370).

14. The electric machine rotor (3000) according to claim 8, wherein a plurality of pole modules (300) are arranged in a row on the rotor yoke (350) along a circumferential direction of the rotor yoke (350), each pole module (300) of the row of pole modules (300) being aligned with each other in the circumferential direction of the rotor yoke (350), and wherein a plurality of pole modules (300) are arranged in a column on the rotor yoke (350) along an axial direction parallel to a central rotational axis of the electric machine rotor (3000), each pole module (300) of the column of pole modules (300) being aligned with each other in the axial direction parallel to the central rotational axis of the electric machine rotor (3000).

15. The electric machine rotor (3000) of claim 8, wherein circumferentially adjacent pole units in different pole modules are of opposite polarity and axially adjacent pole units in different pole modules are of the same polarity.

16. A method of manufacturing an electric machine rotor (3000), the method comprising:

arranging a pair of magnetic pole units (320, 330) with opposite polarities on a substrate (310) in parallel;

snap-fitting a cover piece (340) over the pair of pole units (320, 330) and the base plate (310) such that a first and second spaced apart portions (341a, 341b) of the cover piece (340) respectively cover each of the pair of pole units (320, 330) and such that the pair of pole units (320, 330) are spaced apart by a first distance;

pouring resin into an accommodation space formed by the cover (340) and the base plate (310), thereby forming a pole module (300);

arranging a plurality of pole modules (300) on a rotor yoke (350) such that different circumferentially adjacent pole modules (300) are spaced apart from each other along a circumferential direction of the rotor yoke (350) by a second distance, the first distance being different from the second distance.

17. The method of claim 16, further comprising: when the cover 340 is fastened, a third portion 341c between a first portion 341a and a second portion 341b of the cover 340 and recessed toward the substrate 310 with respect to the first portion 341a and the second portion 341b covers a middle portion of the substrate 310.

18. The method of claim 16, wherein before fastening the cover case (340), an adhesive is applied to a front surface of each of the pair of pole units (320, 330) for adhering the front surface to the cover case (340);

after the cover case (340) is fastened to the pair of pole units (320, 330), pressing the front surfaces of the cover case (340) and the pair of pole units (320, 330) to completely spread out the adhesive between the cover case (340) and the front surfaces of the pair of pole units (320, 330);

sealing an external seam between the cover 340 and the base 310 such that the cover 340 and the base 310 form a sealed space.

19. The method of claim 16, wherein the casing (340) further comprises an evacuation nozzle (348) and a glue injection nozzle (349) respectively provided on both end surfaces of the casing (340), the method further comprising the steps of:

pouring resin into the inside of the accommodating space formed by the cover case (340) and the substrate (310) through the vacuum-pumping nozzle (348) and the glue-pouring nozzle (349) so that each gap between the cover case (340), the substrate (310) and the pair of magnetic pole units (320, 330) is filled with resin, removing the vacuum-pumping nozzle (348) and the glue-pouring nozzle (349) after the pouring of resin is completed, and applying sealant to the position where the glue-pouring nozzle (349) and the vacuum-pumping nozzle (348) are removed for sealing.

20. The method of claim 17, wherein one or more substrate through holes (315) are provided in the substrate (310), one or more housing through holes (345) are provided in the third portion (341c) of the housing (340), and one or more threaded holes are provided in the rotor yoke (350), the method further comprising the steps of:

mechanically securing a pole module (300) to the rotor yoke (350) by passing one or more fasteners (370) through the one or more base plate through holes (315), the one or more cover through holes (345) and the one or more threaded holes, respectively, and reversing the polarity of circumferentially adjacent pole units in different pole modules, the polarity of axially adjacent pole units in different pole modules being the same.