JP2013093979A - Synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synchronous motor that can further increase output torque by increasing a magnetic flux of permanent magnets as much as possible.SOLUTION: A motor 1 includes: a rotor 20 including a main rotor core 23 having first permanent magnets 25 buried therein and a sub rotor core 24 that have second permanent magnets 26 buried therein and is disposed outside in an axial direction of the main rotor core 23; a stator 10; and an exciting coil 30 disposed outside in an axial direction of the stator 10. The first permanent magnets 25 and the second permanent magnets 26 are respectively comprised of a pair of planer magnets that extend along the axial direction and a substantially radial direction of the main rotor core 23 or the sub rotor core 24, and are disposed oppositely in a circumferential direction so that a circumferential distance therebetween is increased from the inside in the radial direction to the outside in the radial direction. A cross-sectional area of a region Z1 corresponding to space between the pair of second permanent magnets 26 is larger than a cross-sectional area of a region X corresponding to space between the pair of first permanent magnets 25.

Description

  The present invention relates to a synchronous motor having a rotor in which a permanent magnet is embedded. In particular, the present invention relates to a hybrid excitation motor that appropriately increases interlinkage magnetic flux of a stator coil using magnetic flux generated separately from magnetic flux generated by a permanent magnet of a rotor.

  In a synchronous motor having a rotor in which a permanent magnet is embedded, magnetic flux weakening control (field weakening control) is generally applied in a high-speed rotation range. By applying the flux weakening control, the motor is intended to expand the driving range in the high-speed rotation region by suppressing the amount of magnetic flux related to the field by the permanent magnet. However, the efficiency decreases as the weak magnetic flux current flows. Furthermore, if the amount of magnetic flux by the permanent magnet is suppressed, there is a problem that the torque that can be output is reduced.

  In order to solve such problems, a motor called a hybrid excitation type has been developed in recent years. The hybrid excitation type motor increases the output torque by appropriately increasing the linkage magnetic flux of the stator coil using the magnetic flux generated separately from the magnetic flux generated by the permanent magnet of the rotor. A conventional technique related to a hybrid excitation type motor is disclosed in Patent Document 1.

  The hybrid excitation motor described in Patent Document 1 includes a field winding for generating a magnetic flux different from the magnetic flux generated by the permanent magnet of the rotor. The field winding is disposed outside the end in the rotation axis direction of the rotor. A protrusion is provided between the rotor main body and the field winding on the outer side in the rotation axis direction of the rotor main body facing the stator in the radial direction.

JP 2011-67048 A

  Since the conventional hybrid excitation motor described in Patent Document 1 increases magnetic flux by a field winding, a protrusion is provided with respect to a rotor configuration (rotor main body) that is originally provided in a normal motor. However, the projecting portion is merely for suitably forming a magnetic path by the field winding, and the basic configuration such as arrangement of permanent magnets is the same as that of the rotor main body. Thus, in order to increase the magnetic flux generated by the field winding as much as possible, it cannot be said that special consideration is given to the configuration using the field winding. Therefore, this conventional motor may not be able to obtain a sufficient output torque.

  The present invention has been made in view of the above points, and an object thereof is to provide a synchronous motor capable of further increasing output torque by increasing magnetic flux generated by external excitation as much as possible.

  In order to solve the above problems, a synchronous motor according to the present invention includes a main rotor core in which a first permanent magnet is embedded and a sub-rotor core in which a second permanent magnet is embedded and arranged on the outer side in the axial direction of the main rotor core. And a stator having a winding portion for driving to rotationally drive the rotor disposed radially outside the rotor, and formed between the rotor and the stator disposed axially outside the stator. An excitation winding for increasing the magnetic flux, and the main rotor core and the sub-rotor core are configured by arranging N-pole and / or S-pole magnetic poles in parallel along the circumferential direction and having the same polarity. The magnetic poles are arranged along the axial direction, and the first permanent magnet and the second permanent magnet are in the axial direction and the substantially radial direction of the main rotor core or the sub rotor core. It is composed of a pair of magnets extending along the circumferential direction so as to be opposed to each other, and the paired magnets are arranged so that a circumferential interval between them increases from the radially inner side toward the radially outer side, The cross-sectional area perpendicular to the axial direction of the pair of magnets included in the sub-rotor core has a cross-sectional area perpendicular to the axial direction of the pair of magnets included in the main rotor core. The cross-sectional area is perpendicular to the cross section.

  According to the configuration of the present invention, it is possible to provide a synchronous motor capable of further increasing output torque by increasing magnetic flux generated by external excitation as much as possible.

It is the perspective view which showed the cross section parallel to the axial direction of the motor which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the state which decomposed | disassembled the stator of the motor of FIG. It is a perspective view which shows the state which decomposed | disassembled the rotor of the motor of FIG. It is a perspective view of the rotor core of the motor shown in FIG. FIG. 5 is a perspective view of a main rotor core of the rotor core shown in FIG. 4. It is a perspective view of the subrotor core of the rotor core shown in FIG. It is a perspective view which shows the flow of the magnetic flux by the main rotor core of the motor of FIG. It is a perspective view which shows the flow of the magnetic flux by the subrotor core of the motor of FIG. It is a perspective view which shows the flow of the magnetic flux by the excitation part of the motor of FIG. FIG. 6 is a partial cross-sectional view perpendicular to the axial direction of the main rotor core shown in FIG. 5. FIG. 7 is a partial cross-sectional view (Comparative Example 1) perpendicular to the axial direction of the auxiliary rotor core shown in FIG. 6. FIG. 7 is a partial cross-sectional view (Comparative Example 2) perpendicular to the axial direction of the auxiliary rotor core shown in FIG. 6. FIG. 7 is a partial cross-sectional view (Example 1) perpendicular to the axial direction of the auxiliary rotor core shown in FIG. 6. It is a table | surface which shows the comparison of the magnetic flux amount in Example 1 and Comparative Examples 1 and 2. FIG. FIG. 7 is a partial cross-sectional view perpendicular to the axial direction of the sub-rotor core shown in FIG. 6 (Example 2). FIG. 7 is a partial cross-sectional view (Example 3) perpendicular to the axial direction of the auxiliary rotor core shown in FIG. 6. It is a table | surface which shows the comparison of the magnetic flux amount in Examples 1-3. It is a fragmentary sectional view perpendicular | vertical to the axial direction of the subrotor core of the motor which concerns on the 2nd Embodiment of this invention. It is a fragmentary sectional view perpendicular | vertical to the axial direction of the subrotor core of the motor which concerns on the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, the structure of the motor according to the first embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view showing a cross section parallel to the axial direction of the motor, FIG. 2 is a perspective view showing a state in which the stator of the motor is disassembled, FIG. 3 is a perspective view showing a state in which the rotor is disassembled, and FIG. FIG. 5 is a perspective view of the main rotor core, and FIG. 6 is a perspective view of the sub rotor core.

  As shown in FIG. 1, the motor 1 is a so-called hybrid excitation type synchronous motor including a stator 10, a rotor 20, and an excitation unit 30 inside the motor case 2 and the lid 3.

  The motor case 2 has a bottomed cylindrical shape having an opening surface at one end in the axial direction of the motor 1. The lid portion 3 has a disk shape and is provided at the position of the opening surface so as to close the opening surface of the motor case 2. The lid 3 is fixed to the opening surface of the motor case 2 with a bolt (not shown).

  As shown in FIGS. 1 and 2, the stator 10 is a stator that is made of an annular magnetic material and fixedly arranged inside the motor case 2. The stator 10 includes a stator core 11. The stator core 11 includes an annular stator yoke 12 and a stator tooth 13 extending so as to protrude radially inward from an inner peripheral portion of the stator yoke 12.

  For example, twelve stator teeth 13 are arranged in the circumferential direction of the motor 1 so as to make one round. That is, twelve slots 14 are formed in the stator 10. The stator teeth 13 are integrally formed by, for example, laminating a plurality of steel plates in the axial direction.

  An insulator 15 constituting a bobbin made of an electrically insulating member is attached to the outer periphery of the stator teeth 13. Furthermore, a drive coil 16 (drive winding portion) around which an electric wire is wound along the axial direction is formed outside the insulator 15. In FIG. 2, only two drive coils 16 in the vicinity of the cross section are drawn, and the drive coil 16 is not drawn in a portion between them along the circumferential direction. A current for rotating the rotor 20 is passed through the drive coil 16.

  As shown in FIGS. 1 and 3, the rotor 20 is a rotor that is made of a magnetic material having a substantially cylindrical shape and is rotatably arranged inside the stator 10. The rotor 20 includes a shaft 21 and a rotor core 22 fixed to the peripheral surface of the shaft 21 so as not to be displaced. Both ends of the shaft 21 are supported by the motor case 2 and the lid 3 via two bearings 4. The rotor core 22 includes a main rotor core 23 and a sub-rotor core 24 each having a substantially cylindrical shape fixed to a shaft 21 positioned at the center in the radial direction and arranged side by side in the axial direction. The rotor core 22 has a total axial length of 70 mm, for example.

  As shown in FIGS. 3 to 5, the main rotor core 23 is configured by arranging two magnetic poles of N poles and S poles alternately along the circumferential direction. The number of poles of the main rotor core 23 is eight. A first permanent magnet 25 is embedded in each magnetic pole of the main rotor core 23. The first permanent magnet 25 of each magnetic pole is composed of a pair of plate-like magnets that extend along the axial direction and the substantially radial direction of the main rotor core 23 and are arranged to face each other in the circumferential direction. The main rotor core 23 has an axial length of, for example, 42 mm.

  As shown in FIGS. 1 and 4, the sub-rotor core 24 is provided at two locations outside the axial both ends of the main rotor core 23. The sub rotor core 24 has substantially the same diameter as the main rotor core 23 and is shorter in the axial direction than the main rotor core 23, for example, 14 mm. The sub-rotor core 24 has an interval of one pole in the circumferential direction with respect to the arrangement of the two magnetic poles of the N pole and the S pole along the circumferential direction of the main rotor core 23, and the magnetic pole of the N pole or S pole is in the circumferential direction. Are arranged along. That is, the sub-rotor core 24 has N or S poles arranged in the circumferential direction with an electrical angle of every 360 degrees. As a result, the number of poles of the sub-rotor core 24 is 4, and the magnetic poles having the same polarity as the main rotor core 23 are arranged along the axial direction. One sub-rotor core 24 is provided with only N-pole magnetic poles, and the other sub-rotor core 24 is provided with only S-pole magnetic poles.

  A second permanent magnet 26 is embedded in each magnetic pole of the sub rotor core 24. Similarly to the first permanent magnet 25 of the main rotor core 23, the second permanent magnet 26 of each magnetic pole extends along the axial direction and the substantially radial direction of the sub-rotor core 24 and forms a pair of plates arranged to face each other in the circumferential direction. It is composed of a magnet. The second permanent magnet 26 is disposed at a location substantially corresponding to the first permanent magnet 25 in the axial direction. That is, the second permanent magnet 26 is arranged so as to be substantially aligned with the first permanent magnet 25 along the axial direction.

  As shown in FIGS. 1 and 2, the exciter 30 is annularly provided at two locations outside the axial end portions of the stator 10 and the rotor 20. Each excitation section 30 includes an excitation coil 31 (excitation winding section) and an excitation core 32.

  The exciting coil 31 is formed by winding an electric wire along the circumferential direction of the motor 1 inside an annular recess 32 a provided inside the exciting core 32. The exciting core 32 is made of a magnetic material having a substantially donut shape along the circumferential direction of the motor 1 and includes an annular recess 32a that is recessed from the stator 10 side toward the outside in the axial direction. The end surfaces of the exciting core 32 on the stator 10 and rotor 20 side are close to the end surfaces of the stator 10 and the rotor 20 in the axial direction, thereby substantially closing the opening surface of the annular recess 32a. And the annular recessed part 32a of the exciting core 32 accommodates the location of the edge part of the axial direction of the insulator 15 and the drive coil 16 with the exciting coil 31. FIG.

  Next, the flow of magnetic flux generated in the motor 1 having the above configuration will be described with reference to FIGS. 7 is a perspective view showing the flow of magnetic flux by the main rotor core 23, FIG. 8 is a perspective view showing the flow of magnetic flux by the sub-rotor core 24, and FIG. 9 is a perspective view showing the flow of magnetic flux by the excitation unit 30.

  The magnetic flux by the main rotor core 23 flows along the broken line A with an arrow shown in FIG. For example, if the magnetic flux generated by the main rotor core 23 starts from the N pole of the main rotor core 23, the air gap between the main rotor core 23 and the stator core 11, the stator core 11, the air gap between the stator core 11 and the main rotor core 23, the main rotor core It flows in the order of 23 S poles. The magnetic flux generated by the main rotor core 23 is a magnetic flux that flows along a plane that is substantially perpendicular to the axial direction.

  The magnetic flux generated by the sub-rotor core 24 flows along a broken line B with an arrow shown in FIG. For example, when the magnetic flux generated by the sub-rotor core 24 starts from the N pole of the sub-rotor core 24, the air gap between the sub-rotor core 24 and the stator teeth 13, the stator teeth 13, and then the stator yoke 12 flow obliquely in the axial direction. It flows in the order of the air gap between the stator teeth 13 and the sub rotor core 24 and the south pole of the sub rotor core 24. The magnetic flux generated by the sub-rotor core 24 is a magnetic flux that flows along a plane that is substantially perpendicular to the axial direction.

  The magnetic flux generated by the excitation unit 30 flows along a broken line C with an arrow shown in FIG. For example, when the magnetic flux generated by the excitation unit 30 starts from the magnetic pole of the sub-rotor core 24, the air gap between the sub-rotor core 24 and the stator core 11, the air between the stator core 11, the excitation core 32, and the excitation core 32 and the sub-rotor core 24. It flows in the order of the gap and the magnetic poles of the sub-rotor core 24. The magnetic flux generated by the excitation unit 30 is a magnetic flux that flows along a plane that is substantially parallel to the axial direction.

  In this manner, a magnetic flux that flows three-dimensionally is generated in the motor 1 that is a hybrid excitation type synchronous motor.

  In the motor 1 configured as described above, the rotor 20 is rotationally driven by passing an appropriate current to the drive coil 16 of the stator 10 with respect to the magnetic flux generated from the first permanent magnet 25 and the second permanent magnet 26 of the rotor 20.

  In order to expand the driving range in the high-speed rotation range, the magnetic flux weakening control (field weakening control) is applied to the motor 1 having the rotor 20 in which the first permanent magnet 25 and the second permanent magnet 26 are embedded. When the motor 1 suppresses the amount of magnetic flux related to the field by the first permanent magnet 25 and the second permanent magnet 26 in order to improve the efficiency in the high-speed rotation range, the torque that can be output is reduced. Therefore, the motor 1 increases the output torque by appropriately increasing the magnetic flux interlinked with the drive coil 16 of the stator 10 using the magnetic flux generated by the excitation unit 30.

  In the motor 1, the rotor 20 has a unique configuration for further increasing the output torque by increasing the external excitation, that is, the magnetic flux generated by the excitation unit 30 as much as possible.

  Next, a detailed configuration of the rotor 20 will be described with reference to FIGS. 10 is a partial cross-sectional view perpendicular to the axial direction of the main rotor core 23, FIG. 11 is a partial cross-sectional view perpendicular to the axial direction of the sub-rotor core 24 (Comparative Example 1), and FIG. 12 is a portion perpendicular to the axial direction of the sub-rotor core 24. Cross-sectional view (Comparative Example 2), FIG. 13 is a partial cross-sectional view perpendicular to the axial direction of the sub-rotor core 24 (Example 1), and FIG. 14 is a table showing a comparison of magnetic flux amounts in Example 1 and Comparative Examples 1 and 2. is there. 15 is a partial cross-sectional view perpendicular to the axial direction of the sub-rotor core 24 (Example 2), FIG. 16 is a partial cross-sectional view perpendicular to the axial direction of the sub-rotor core 24 (Example 3), and FIG. It is a table | surface which shows the comparison of the magnetic flux amount in.

  The amount of magnetic flux shown in FIGS. 14 and 17 is the result of performing a three-dimensional transient analysis using a commercially available electromagnetic field analysis tool. “Magnetic flux by magnet” in the figure indicates the maximum value of the magnetic flux linked to the drive coil 16 of the stator 10 when the drive current is zero. “Magnetic flux due to excitation” in the figure indicates magnetic flux generated when the energization current to the exciting coil 31 of the exciting unit 30 is 30 A DC.

  The main rotor core 23 includes a first permanent magnet 25 embedded in each magnetic pole as shown in FIG. As described above, the first permanent magnet 25 of each magnetic pole is composed of a pair of plate-like magnets that extend along the axial direction and the substantially radial direction of the main rotor core 23 and are arranged to face each other in the circumferential direction. The plate-shaped magnets forming a pair as the first permanent magnet 25 have a V-shaped shape in a plan view as viewed from the axial direction so that the circumferential interval increases from the radially inner side to the radially outer side. Has been placed. A region X (shaded portion) having a fan shape in a plan view viewed from the axial direction is formed at a position corresponding to each other between the pair of first permanent magnets 25.

  The first permanent magnet 25 has, for example, a rectangular shape in a plan view when viewed from the axial direction in which the length in the radial direction is 14 mm and the width orthogonal to the first permanent magnet 25 is 4 mm. A gap 25 a having a substantially triangular shape in plan view is provided adjacent to the first permanent magnet 25 on the radially inner side of the first permanent magnet 25. The gaps 25a adjacent to each other of the pair of first permanent magnets 25 are opposed to each other with a relatively narrow interval.

  FIG. 11 shows a sub-rotor core 24 as a comparative example 1 with respect to the main rotor core 23 having such a shape. Comparative Example 1 has a configuration corresponding to a conventional hybrid excitation motor.

  The sub-rotor core 24 as the comparative example 1 includes a second permanent magnet 26 embedded in each magnetic pole. As described above, the second permanent magnet 26 of each magnetic pole is composed of a pair of plate-like magnets that extend along the axial direction and the substantially radial direction of the sub-rotor core 24 and are arranged to face each other in the circumferential direction. The plate-shaped magnets forming a pair as the second permanent magnet 26 have a V-shape in a plan view as viewed from the axial line side so that the interval in the circumferential direction increases from the radially inner side to the radially outer side. Has been placed.

  The second permanent magnet 26 has a rectangular shape in a plan view when viewed from the axial direction with a length of 14 mm in the radial direction and a width of 4 mm perpendicular thereto, that is, has the same shape as the first permanent magnet 25 of the main rotor core 23. Yes. The second permanent magnet 26 is disposed at a position corresponding to the first permanent magnet 25 in the axial direction. As a result, the cross-sectional area perpendicular to the axial direction of the fan-shaped region Y1 (shaded portion) in a plan view as viewed from the axial direction formed between the corresponding pairs of the second permanent magnets 26. Is the same as the cross-sectional area of the region X of the main rotor core 23.

  FIG. 14 shows the amount of magnetic flux when the sub-rotor core 24 of Comparative Example 1 shown in FIG. 11 is applied to the main rotor core 23 shown in FIG. According to this, the magnetic flux by the magnet, that is, the first permanent magnet 25 and the second permanent magnet 26 is 0.0265 [Wb], and the magnetic flux by the excitation, that is, the exciting unit 30, is 0.0045 [Wb]. The magnetic flux is 0.0310 [Wb].

  Next, a sub-rotor core 24 as Comparative Example 2 is shown in FIG. The second permanent magnet 26 of the sub-rotor core 24 of Comparative Example 2 has a rectangular shape in plan view as viewed from the axial direction with a length of 14 mm in the radial direction and a width of 3 mm perpendicular thereto. Note that the cross-sectional area perpendicular to the axial direction of the sector-shaped region Y2 (shaded portion) in a plan view as viewed from the axial direction formed between the corresponding pairs of the second permanent magnets 26 is The cross sectional area of the region X of the main rotor core 23 is substantially the same. That is, the secondary rotor core 24 of the comparative example 2 has a width of the second permanent magnet 26 that is rectangular in plan view at the outer peripheral edge of the V shape in plan view with respect to the first permanent magnet 25 (the region drawn by a broken line in FIG. 12). ) Is reduced by 1 mm.

  FIG. 14 shows the amount of magnetic flux when the sub rotor core 24 of the comparative example 2 shown in FIG. 12 is applied to the main rotor core 23 shown in FIG. According to this, the magnetic flux by the magnet, that is, the first permanent magnet 25 and the second permanent magnet 26 is 0.0262 [Wb], which is 1% lower than that of the first comparative example. Excitation, that is, the magnetic flux generated by the excitation unit 30 is 0.0045 [Wb], and the increase / decrease relative to Comparative Example 1 is 0%. The total magnetic flux is 0.0307 [Wb], which is 1% lower than that of Comparative Example 1.

  Next, the sub-rotor core 24 as Example 1 is shown in FIG. The second permanent magnet 26 of the sub-rotor core 24 of the first embodiment has a rectangular shape in a plan view as viewed from the axial direction with a length of 14 mm in the radial direction and a width of 3 mm perpendicular thereto. In addition, the sub rotor core 24 of Example 1 is the width | variety (area | region drawn with the broken line in FIG. 13) of the 2nd permanent magnet 26 of the planar view rectangle in the circumferential direction inner edge part of the V shape of planar view with respect to the 1st permanent magnet 25. ) Is reduced by 1 mm. As a result, the cross-sectional area perpendicular to the axial direction of the sector Z1 (shaded portion) in a plan view as viewed from the axial direction formed between the corresponding pairs of the second permanent magnets 26 in the plan view. Is larger than the cross-sectional area of the region X of the main rotor core 23.

  FIG. 14 shows the amount of magnetic flux when the sub-rotor core 24 of the first embodiment shown in FIG. 13 is applied to the main rotor core 23 shown in FIG. According to this, the magnetic flux by a magnet, ie, the 1st permanent magnet 25 and the 2nd permanent magnet 26, is 0.0251 [Wb], and has decreased about 5% compared with comparative example 1. Excitation, that is, the magnetic flux generated by the excitation unit 30 is 0.0059 [Wb], which is about 31% higher than that of the first comparative example. The total magnetic flux is 0.0310 [Wb], and the increase / decrease relative to Comparative Example 1 is 0%.

  As in the first embodiment, the pair of second permanent magnets 26 included in the sub-rotor core 24 has a cross-sectional area perpendicular to the axial direction of the corresponding region Z1 between the first permanent magnets 26. By making the cross-sectional area perpendicular to the axial direction of the region X corresponding to each other between the permanent magnets 25, the magnetic flux generated by the excitation unit 30 can be greatly increased compared to the comparative example 1 showing the conventional motor configuration. it can. Moreover, although the magnetic flux by the 1st permanent magnet 25 of the sub-rotor core 24 of Example 1 and the 2nd permanent magnet 26 has decreased slightly with respect to the conventional comparative example 1, the total magnetic flux is substantially the same.

  Next, the sub-rotor core 24 as the second embodiment is shown in FIG. The second permanent magnet 26 of the sub-rotor core 24 of Example 2 has a rectangular shape in a plan view when viewed from the axial direction with a length of 14 mm in the radial direction and a width of 3 mm perpendicular thereto. In addition, the 2nd permanent magnet 26 which makes the pair arrange | positioned in planar view V shape in Example 1 is comprised by the arrangement | positioning which opened the V-shaped top part widely in Example 2. FIG. The second permanent magnet 26 according to the second embodiment is arranged so as to be parallel to the radial line R extending from the axial center of the sub-rotor core 24. As a result, a region Z2 (shaded portion) formed at a location corresponding to each other between the pair of second permanent magnets 26 has a substantially trapezoidal shape in a plan view when viewed from the axial direction, and is perpendicular to the axial direction. The cross-sectional area is larger than the cross-sectional area of the region X of the main rotor core 23. Further, the cross-sectional area perpendicular to the axial direction of the region Z2 of the second embodiment is larger than the cross-sectional area of the region Z1 of the first embodiment.

  FIG. 17 shows the amount of magnetic flux when the sub-rotor core 24 of the second embodiment shown in FIG. 15 is applied to the main rotor core 23 shown in FIG. According to this, the magnetic flux by a magnet, ie, the 1st permanent magnet 25 and the 2nd permanent magnet 26, is 0.0207 [Wb], and has decreased about 18% compared with Example 1. Excitation, that is, the magnetic flux generated by the excitation unit 30 is 0.0079 [Wb], which is about 34% higher than that in the first embodiment. The total magnetic flux is 0.0286 [Wb], which is about 8% less than that of the first embodiment.

  As in the second embodiment, a region Z2 corresponding to each other between the pair of second permanent magnets 26 included in the sub-rotor core 24 is substantially trapezoidal with respect to the fan-shaped region Z1 of the first embodiment and is axial. By increasing the cross-sectional area perpendicular to the magnetic field, the magnetic flux generated by the excitation unit 30 can be greatly increased. In addition, compared with Example 1, the magnetic flux and the total magnetic flux by the 1st permanent magnet 25 and the 2nd permanent magnet 26 of the sub-rotor core 24 of Example 2 have decreased a little.

  Next, the sub-rotor core 24 as Example 3 is shown in FIG. The second permanent magnet 26 of the sub-rotor core 24 of Example 3 has a rectangular shape in plan view as viewed from the axial direction with a length of 14 mm in the radial direction and a width of 3 mm perpendicular thereto. And the 2nd permanent magnet 26 which makes the pair arrange | positioned in planar view V shape in Example 1 was formed in the location corresponding to each other between the tops of V shape which were opened widely in Example 3. The region Z3 (shaded portion) has a substantially trapezoidal shape in a plan view viewed from the axial direction. In addition, regarding the magnetic pole of the sub-rotor core 24 divided every 45 degrees in the mechanical angle, the second permanent magnet 26 is arranged so as to protrude into an adjacent area beyond the area divided every 45 degrees. As a result, the cross-sectional area perpendicular to the axial direction of the region Z3 formed at a position corresponding to each other between the pair of second permanent magnets 26 is larger than the cross-sectional area of the region X of the main rotor core 23. Further, the cross-sectional area perpendicular to the axial direction of the region Z3 of the third embodiment is wider than the cross-sectional area of the region Z1 of the first embodiment and the cross-sectional area of the region Z2 of the second embodiment.

  FIG. 17 shows the amount of magnetic flux when the sub rotor core 24 of the third embodiment shown in FIG. 16 is applied to the main rotor core 23 shown in FIG. According to this, the magnetic flux by a magnet, ie, the 1st permanent magnet 25 and the 2nd permanent magnet 26, is 0.0189 [Wb], and has decreased about 25% compared with Example 1. Excitation, that is, the magnetic flux generated by the excitation unit 30 is 0.0074 [Wb], which is about 25% higher than that of the first embodiment. The total magnetic flux is 0.0263 [Wb], which is about 15% lower than that of the first embodiment.

  As in the third embodiment, the region Z3 corresponding to each other between the pair of second permanent magnets 26 included in the sub-rotor core 24 is substantially trapezoidal with respect to the sector Z1 forming the fan shape of the first embodiment and is axial. By increasing the cross-sectional area perpendicular to the magnetic field, the magnetic flux generated by the excitation unit 30 can be greatly increased. In addition, compared with Example 1, the magnetic flux and total magnetic flux by the 1st permanent magnet 25 and the 2nd permanent magnet 26 of the subrotor core 24 of Example 3 have decreased a little. Furthermore, compared to Example 2, the overall magnetic flux of Example 3 is reduced. Therefore, the region corresponding to each other between the pair of second permanent magnets 26 included in the sub-rotor core 24 exceeds the region of the magnetic poles of the sub-rotor core 24 in which the second permanent magnets 26 are divided every 45 degrees in mechanical angle. It is desirable that they are formed so as not to protrude into adjacent areas. That is, it can be said that the cross-sectional area perpendicular to the axial direction of the corresponding region between the pair of second permanent magnets 26 is almost the upper limit of the cross-sectional area of the region Z2 of the second embodiment.

  As in the first to third embodiments, the motor 1 forms a pair as each of the first permanent magnet 25 and the second permanent magnet 26 configured by a pair of plate magnets goes from the radially inner side to the radially outer side. The regions Z1, Z2, and Z3 corresponding to each other between the pair of second permanent magnets 26 are arranged so that the circumferential interval between the plate-shaped magnets is widened (V-shaped or substantially trapezoidal as viewed in the axial direction). Is larger than the cross-sectional area perpendicular to the axial direction of the region X corresponding to each other between the pair of first permanent magnets 25. Thus, the cross-sectional area perpendicular to the axial direction of the region corresponding to each other between the pair of second permanent magnets 26 is perpendicular to the axial direction of the region corresponding to each other between the pair of first permanent magnets 25. Compared with the case where the cross-sectional area is substantially the same, the magnetic flux generated by the excitation unit 30 can be greatly increased.

  In the first embodiment, the second permanent magnet 26 and the first permanent magnet 25 are arranged so as to be substantially aligned along the axial direction. Therefore, the magnetic flux and the total magnetic flux by the first permanent magnet 25 and the second permanent magnet 26 are arranged. The magnetic flux generated by the excitation unit 30 can be greatly increased without substantially changing. Therefore, even when the excitation unit 30 is not used, the motor 1 exhibits efficient rotation performance.

  In the second and third embodiments, the cross-sectional area of the regions Z2 and Z3 between the paired second permanent magnets 26 is wider than the cross-sectional area of the region X between the paired first permanent magnets 25. The second permanent magnet 26 (further wider than the cross-sectional area of the region Z1 of the first embodiment) is arranged so as to be shifted from a position corresponding to the first permanent magnet 25 in the axial direction. Thus, in Examples 2 and 3, although the magnetic flux and the total magnetic flux generated by the first permanent magnet 25 and the second permanent magnet 26 are smaller than those in the first and comparative examples 1, the magnetic flux generated by the excitation unit 30 is further increased than that in the first embodiment. Can be greatly increased. When the magnetic flux generated by the permanent magnet is low, the range of rotation that can be operated with the same voltage is widened, which is effective. Moreover, although the torque which can be output will fall if the magnetic flux by a permanent magnet is low, the magnetic flux of a permanent magnet can be increased suitably at a desired timing by using the excitation part 30. FIG.

  Further, the motor 1 is configured such that the main rotor core 23 has N-pole and S-pole magnetic poles (8 poles) arranged alternately along the circumferential direction, and the sub-rotor core 24 extends along the circumferential direction of the main rotor core 23. An N-pole or S-pole magnetic pole (four poles) is arranged along the circumferential direction at intervals of one pole in the circumferential direction with respect to the arrangement of the N-pole and S-pole magnetic poles. The magnetic poles having the same polarity as the rotor core 23 are arranged corresponding to the axial direction, that is, arranged in a state of being aligned along the axial direction. Thereby, even if there is no permanent magnet, the magnetic flux generated using the excitation unit 30 can be effectively utilized.

  Moreover, since the paired first permanent magnet 25 and the paired second permanent magnet 26 are both plate-shaped, it is easy to induce the flow of magnetic flux. Therefore, the magnetic flux by the excitation part 30 can be increased effectively.

  Further, the first permanent magnet 25 and the second permanent magnet 26 that form a pair are rectangular in a plan view when viewed from the axial direction of the main rotor core 23 or the sub-rotor core 24, and therefore the magnets that form a pair The cross-sectional area perpendicular to the axial direction of the region corresponding to the gap can be easily enlarged and secured. Therefore, the magnetic flux generated by the excitation unit 30 can be increased more effectively.

  And according to the structure of the said embodiment, the motor 1 which can increase the output torque further by increasing external excitation, ie, the magnetic flux which generate | occur | produces by the excitation part 30, as much as possible can be provided.

  Next, a detailed configuration of the motor according to the second embodiment of the present invention will be described with reference to FIG. FIG. 18 is a partial cross-sectional view perpendicular to the axial direction of the sub-rotor core of the motor. Since the basic configuration of this embodiment is the same as that of the first embodiment described with reference to FIGS. 1 to 17, the same reference numerals are assigned to the same components as those of the first embodiment. The description of the drawings and the description thereof will be omitted.

  In the motor 1 according to the second embodiment, a second permanent magnet 27 is embedded in the sub-rotor core 24 as shown in FIG. The second permanent magnet 27 of each magnetic pole is composed of a pair of plate-like magnets that extend along the axial direction and the substantially radial direction of the sub-rotor core 24 and are arranged to face each other in the circumferential direction. The second permanent magnet 27 has an arc shape in a plan view viewed from the axial direction. The first permanent magnet 25 of the main rotor core 23 may be formed in the same arc shape.

  The second permanent magnet 27 is disposed at a position substantially corresponding to the first permanent magnet 25 in the axial direction. That is, the second permanent magnet 27 is arranged so as to be substantially aligned with the first permanent magnet 25 along the axial direction.

  Thus, the first permanent magnet 25 that makes a pair and the second permanent magnet 27 that makes a pair have an arc shape in a plan view as viewed from the axial direction of the main rotor core 23 or the sub-rotor core 24. As in the embodiment, the cross-sectional area perpendicular to the axial direction of the corresponding region between the pair of magnets can be easily enlarged and secured. Therefore, the magnetic flux generated by the excitation unit 30 can be increased more effectively.

  The second permanent magnets 27 that form a pair of arcs shown in FIG. 18 are configured with arcs that protrude outward toward the opposite direction, but are configured with arcs that protrude inward. May be.

  Next, a detailed configuration of the motor according to the third embodiment of the present invention will be described with reference to FIG. FIG. 19 is a partial cross-sectional view perpendicular to the axial direction of the sub-rotor core of the motor. Since the basic configuration of this embodiment is the same as that of the first embodiment described with reference to FIGS. 1 to 17, the same reference numerals are assigned to the same components as those of the first embodiment. The description of the drawings and the description thereof will be omitted.

  In the motor 1 according to the third embodiment, a second permanent magnet 28 is embedded in the sub-rotor core 24 as shown in FIG. The second permanent magnet 28 of each magnetic pole is composed of a pair of plate-like magnets that extend along the axial direction and the substantially radial direction of the sub-rotor core 24 and are arranged to face each other in the circumferential direction. The second permanent magnet 28 has a so-called oval shape in which a part of a sector shape is missing in a plan view viewed from the axial direction. Note that the first permanent magnet 25 of the main rotor core 23 may also be formed in a similar oval shape.

  The second permanent magnet 28 is disposed at a position substantially corresponding to the first permanent magnet 25 in the axial direction. That is, the second permanent magnet 28 is arranged so as to be substantially aligned with the first permanent magnet 25 along the axial direction.

  In this way, the paired first permanent magnets 25 and the paired second permanent magnets 28 are not circular in plan view as viewed from the axial direction of the main rotor core 23 or the sub-rotor core 24. As in the embodiment, the cross-sectional area perpendicular to the axial direction of the region corresponding to each other between the pair of magnets can be easily enlarged and secured. Therefore, the magnetic flux generated by the excitation unit 30 can be increased more effectively.

  Note that the second permanent magnets 28 forming a pair of oval shapes shown in FIG. 19 have a shape having an arc that protrudes outward in the direction in which they face each other, but an arc that protrudes inward. It may have a shape.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, the number of stator teeth 13 and slots 14 of the stator 10 employed in the embodiment of the present invention, the number of magnetic poles of the main rotor core 23 and the sub-rotor core 24 of the rotor 20, the dimensions of the first permanent magnet 25 and the second permanent magnet 26. Is not limited to the above quantities and dimensions, and other quantities and dimensions may be adopted.

  The present invention can be used in a synchronous motor having a rotor in which a permanent magnet is embedded, particularly in a so-called hybrid excitation motor.

1 Motor (synchronous motor)
DESCRIPTION OF SYMBOLS 10 Stator 11 Stator core 12 Stator yoke 13 Stator teeth 16 Drive coil (winding part for drive)
20 rotor 21 shaft 22 rotor core 23 main rotor core 24 sub rotor core 25 first permanent magnet (paired magnet)
26, 27, 28 Second permanent magnet (paired magnet)
30 Excitation part 31 Excitation coil (excitation winding part)
32 Excitation core

Claims (7)

A rotor having a main rotor core embedded with a first permanent magnet and a sub-rotor core embedded with a second permanent magnet and arranged on the outer side in the axial direction of the main rotor core;
A stator having a winding portion for driving, which is disposed on the outer side in the radial direction of the rotor and rotationally drives the rotor;
An excitation winding portion disposed outside the stator in the axial direction to increase the magnetic flux generated between the rotor and the stator, and
The main rotor core and the sub-rotor core are configured such that N-pole and / or S-pole magnetic poles are juxtaposed along the circumferential direction, and the same polarity magnetic poles are arranged along the axial direction.
The first permanent magnet and the second permanent magnet are composed of a pair of magnets extending along the axial direction and the substantially radial direction of the main rotor core or the sub-rotor core and arranged to face each other in the circumferential direction,
The paired magnets are arranged so that a circumferential interval between the magnets increases from the radially inner side toward the radially outer side,
The cross-sectional area perpendicular to the axial direction of the pair of magnets included in the sub-rotor core has a cross-sectional area perpendicular to the axial direction of the pair of magnets included in the main rotor core. Synchronous motor characterized in that it is wider than the cross-sectional area perpendicular to the axis.   2. The synchronous motor according to claim 1, wherein the second permanent magnet is disposed so as to be substantially aligned with the first permanent magnet along the axial direction. The main rotor core is configured by alternately arranging N-pole and S-pole magnetic poles along the circumferential direction along the entire circumference,
The sub-rotor core is spaced at least one pole in the circumferential direction with respect to the arrangement of the N-pole and S-pole magnetic poles along the circumferential direction of the main rotor core, and the N-pole or S-pole magnetic poles are along the circumferential direction. 3. The synchronous motor according to claim 1, wherein magnetic poles having the same polarity as the main rotor core are arranged along the axial direction.   The synchronous motor according to any one of claims 1 to 3, wherein the paired magnets have a plate shape.   5. The synchronous motor according to claim 1, wherein the paired magnets have a rectangular shape in a plan view as viewed from the axial direction of the main rotor core or the sub-rotor core. 6.   5. The synchronous motor according to claim 1, wherein the magnets forming the pair have an arc shape in a plan view when viewed from the axial direction of the main rotor core or the sub-rotor core. 6.   5. The synchronous motor according to claim 1, wherein the magnets forming the pair are formed in a circular shape in a plan view as viewed from the axial direction of the main rotor core or the sub-rotor core.

Images