JP5621373B2 - Permanent magnet embedded rotor and rotating electric machine - Google Patents

Description

  In the present invention, the first embedded hole in which the first permanent magnet is embedded and the second embedded hole in which the second permanent magnet is embedded are formed in the rotor core, and the q is more than the first embedded hole in the rotor core. The present invention relates to an embedded permanent magnet rotor in which a gap is formed at each position close to an axis, and a rotating electric machine including the embedded permanent magnet rotor.

  An example of the rotating electrical machine is Patent Document 1. As shown in FIG. 4, the permanent magnet type reluctance type rotating electrical machine 90 of Patent Document 1 includes a stator 92 having a plurality of armature coils 91 and a rotor 93 inside the stator 92. .

  The rotor 93 includes a cylindrical rotor core 94 and a plurality of magnetic poles. In the direction along each magnetic pole axis of the rotor core 94, rectangular first cavities 95 are formed at intervals of the magnetic pole width. The first cavity 95 is formed at a position where each magnetic pole is sandwiched from both sides. A first permanent magnet 96 is embedded in each of the first cavities 95. In the rotor core 94, a rectangular second cavity 97 is formed between the magnetic poles along the outer periphery of the rotor core 94. A second permanent magnet 98 is embedded in each of the second cavities 97.

  In the permanent magnet type reluctance type rotating electrical machine 90, the first permanent magnet 96 and the second permanent magnet 98 are provided in the rotor core 94, thereby increasing the reluctance torque, and the permanent magnet type reluctance type rotating electrical machine. The 90 torque is increased.

Japanese Patent No. 3597821

  By the way, in the permanent magnet type reluctance type rotating electrical machine 90 of Patent Document 1, since the second permanent magnet 98 is disposed on the surface of the rotor core 94, an alternating magnetic field linked to the second permanent magnet 98 is generated. In many cases, a large eddy current loss has occurred in the second permanent magnet 98. Due to this large eddy current loss, the temperature of the second permanent magnet 98 increases, the second permanent magnet 98 is demagnetized, and the torque of the permanent magnet type reluctance rotating electrical machine 90 decreases.

  For this reason, in order to reduce the alternating magnetic field linked to the second permanent magnet 98, the second permanent magnet 98 is separated from the surface of the rotor core 94 as shown by a two-dot chain line in FIG. It is conceivable to move the embedded position of the permanent magnet 98 (the position where the second cavity 97 is formed) toward the inner peripheral surface of the rotor core 94. However, if the embedding position of the second permanent magnet 98 is moved to the inner peripheral surface side of the rotor core 94, the second permanent magnet 98 and the first permanent magnet 96 come closer to increase the short-circuit magnetic flux. As a result, the magnetic flux from the second permanent magnet 98 to the stator 92 decreases, and the torque of the permanent magnet type reluctance rotating electrical machine 90 decreases.

  Therefore, the short-circuit magnetic flux between the second permanent magnet 98 and the first permanent magnet 96 is reduced while the embedding position of the second permanent magnet 98 is slightly moved toward the inner peripheral surface of the rotor core 94. In order to reduce this, it is conceivable to provide gaps 99 apart from the second cavity 97 on both sides of the second permanent magnet 98 in the long side direction, as indicated by a two-dot chain line in FIG. This gap 99 reduces the short-circuit magnetic flux between the second permanent magnet 98 and the first permanent magnet 96.

  However, if the gap 99 is provided at a position away from the second cavity 97, the meat portion between the gap 99 and the second cavity 97 in the rotor core 94 becomes the mechanical reinforcement bridge 100, and the reinforcement bridge 100 is provided. 100 is continuously provided in the second cavity 97. When the width of the reinforcing bridge 100 is increased in order to ensure the mechanical strength of the reinforcing bridge 100, the reinforcing bridge 100 is routed from the magnetic pole surface (the surface on the outer peripheral surface side of the rotor core 94) of the second permanent magnet 98. The flowing short-circuit magnetic flux increases, and the torque of the permanent magnet type reluctance type rotating electrical machine 90 decreases.

  An object of the present invention is to provide an embedded permanent magnet rotor capable of suppressing a short-circuit magnetic flux while maintaining mechanical strength by a reinforcing bridge, and a rotating electrical machine including the embedded permanent magnet rotor. .

In order to solve the above problems, in the invention according to claim 1, a first embedded hole is formed near the outer peripheral surface of the rotor core inside the stator so as to extend in a direction perpendicular to the d axis. A first permanent magnet is embedded in one embedded hole, and a second embedded hole is formed on both sides of the first permanent magnet in the rotor core so as to extend along the q axis. The present invention relates to a permanent magnet embedded rotor in which a second permanent magnet is embedded, and further, a gap is formed at each position closer to the q axis than the first embedded hole in the rotor core. In the permanent magnet embedded rotor, the gap portion includes a first gap that extends from the magnet end surface near the q axis of the first permanent magnet toward the q axis. And a second gap spaced from the first gap toward the q-axis side, and a reinforcing bridge is formed between the first gap and the second gap, and the first permanent along the d-axis The gap is formed so that the shortest distance from the magnet end surface to the formation surface of the reinforcing bridge in the first gap is 1 / 3T <shortest distance ≦ T, where T is the thickness of the magnet. The gap is formed such that magnetic flux passes between the second permanent magnet and the gap .

  In the invention according to claim 10, a rectangular first embedded hole is formed near the outer peripheral surface of the stator and the rotor core inside the stator so as to extend in a direction perpendicular to the d-axis. A first embedded magnet is embedded in the first embedded hole, and a second embedded hole is formed on both sides of the first permanent magnet in the rotor core so as to extend along the q axis. Embedded with a second permanent magnet, and further embedded with a permanent magnet embedded rotor in which a gap is formed at each position closer to the q axis than the first embedded hole in the rotor core. Regarding the rotating electrical machine, the embedded permanent magnet rotor is the embedded permanent magnet rotor according to any one of claims 1 to 9.

  According to this, since the shortest distance is set to 1 / 3T <shortest distance ≦ T based on the thickness T of the first permanent magnet, the reinforcing bridge is only a predetermined distance from the magnet end face via the first gap. It is located at a distance. For this reason, as compared with the case where the reinforcing bridge is provided so as to be continuous with the magnet end face as in the background art, the magnetic flux path from the magnetic pole face to the reinforcing bridge is lengthened, and the magnetic flux from the magnetic pole face is immediately reinforced. Reaching the bridge is prevented. Further, by increasing the magnetic flux path from the magnetic pole surface to the reinforcing bridge, it is possible to increase the magnetic resistance in the magnetic flux path, and it is possible to reduce the short-circuit magnetic flux using the reinforcing bridge as a path. As a result, just by moving the reinforcing bridge away from the magnet end face by a predetermined distance, while maintaining the mechanical strength without changing the width of the reinforcing bridge, the short-circuit magnetic flux through the reinforcing bridge is reduced, and the rotating electrical machine Torque reduction can be prevented.

  The rotor core is formed by laminating a plurality of magnetic core plates, and the distance between the reinforcing bridge forming surface in the first gap and the reinforcing bridge forming surface in the second gap. May be set to be twice or more the thickness of the core plate.

  Each of the first air gap and the second air gap includes an outer peripheral side forming surface extending along the outer peripheral surface of the rotor core, and a circumferential direction of the rotor core is between the outer peripheral side forming surface and the outer peripheral surface of the rotor core. The distance between the outer peripheral side formation surface and the outer peripheral surface of the rotor core may be set to be twice or more the thickness of the core plate.

According to this, the strength at the time of punching the core plate can be ensured, and deformation of the reinforcing bridge and the outer peripheral side bridge forming portion at the time of punching can be prevented.
Further, the pair of reinforcing bridges positioned on both magnet end surfaces of the first permanent magnet have a square shape that widens the interval between the reinforcing bridges from the outer peripheral surface side to the inner peripheral surface side of the rotor core. It may be formed.

  According to this, the distance from the magnet end surface to the side surface of the reinforcing bridge gradually increases from the outer peripheral surface side to the inner peripheral surface side of the rotor core. Accordingly, as the rotor core moves from the outer peripheral surface side toward the inner peripheral surface side, the magnetic resistance due to the first air gap can be increased, and the short-circuit magnetic flux to the reinforcing bridge via the first air gap can be reduced.

  The first gap has an outer peripheral end located near the outermost peripheral surface of the rotor core and an inner peripheral end located near the innermost peripheral surface of the rotor core. In the magnet, the magnetic pole surface of the first permanent magnet is positioned closer to the inner peripheral surface of the rotor core than the outer peripheral end of the first air gap, and the outer periphery of the rotor core from the inner peripheral end of the first air gap. You may arrange | position so that it may be located in the surface side.

  According to this, by setting the arrangement position of the first permanent magnet in the rotor core, even if the first permanent magnet is arranged near the outer peripheral surface of the rotor core, the first permanent magnet may be too close to the outer peripheral surface. Thus, eddy current loss generated on the surface of the first permanent magnet can be suppressed. Further, in order to reduce the alternating magnetic field interlinked with the first permanent magnet, when the first permanent magnet is separated from the outer peripheral surface of the rotor core and the first permanent magnet is disposed on the inner peripheral surface side of the rotor core, the first permanent magnet is It is prevented that the two permanent magnets are too close to each other, and the magnetic flux from the first permanent magnet to the stator is prevented from decreasing. As a result, eddy current loss can be reduced without reducing the torque of the rotating electrical machine.

  The stator includes a plurality of teeth arranged on an inner periphery of an annular stator core, and a straight line extending along a radial direction of the stator core and passing through an intermediate point in the width direction of the teeth is a center of the teeth. When the pitch between the central axes of adjacent teeth is P, the embedded depth of the first permanent magnet from the outer peripheral surface of the rotor core to the magnetic pole surface along the d axis is 1 / The first permanent magnet may be arranged so as to satisfy 10P <embedding depth <2 / 3P.

  According to this, by setting the range of the embedding depth of the first permanent magnet, it is possible to suitably exhibit the effect that the eddy current loss can be reduced without reducing the torque of the rotating electrical machine. .

  The first permanent magnet has a flat plate shape extending in a direction perpendicular to the d-axis, and the length of the first permanent magnet in the long side direction is set to 1 to 3 times the pitch. It may be.

  According to this, by setting the length of the first permanent magnet in the long side direction, it is possible to prevent the magnetic flux from being reduced due to the first permanent magnet being too short, and the gap portion and the second in the magnetic pole. The arrangement of the permanent magnets can be suitably set.

The interval between the second permanent magnet and the second gap may be set to 0.3 to 2 times the pitch.
According to this, by setting the interval, it is possible to suppress an increase in torque ripple while suppressing a decrease in torque of the rotating electrical machine.

  In addition, the second permanent magnet is arranged in a V shape extending from the inner peripheral surface side of the rotor core toward the outer peripheral surface side, or an arc shape recessed from the outer peripheral surface side of the rotor core toward the inner peripheral surface side. Also good.

  According to this, the magnetic flux passing through the q-axis can be increased, and the reluctance torque of the rotating electrical machine can be increased.

  According to the present invention, it is possible to suppress the short-circuit magnetic flux while maintaining the mechanical strength by the reinforcing bridge.

The top view which shows the permanent magnet embedding type rotary electric machine of embodiment. The elements on larger scale which show the magnetic pole in a permanent magnet embedded rotor. The elements on larger scale which show another example of a 2nd permanent magnet. The top view which shows background art.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, an embedded permanent magnet type rotating electrical machine M as a rotating electrical machine includes an annular stator 10 and an embedded permanent magnet rotor 15 (hereinafter referred to as a rotatable stator 10). , Simply described as a rotor 15). The stator 10 includes an annular stator core 11, and the stator core 11 is configured by laminating a plurality of core plates made of a magnetic material (steel plate).

  A plurality of teeth 13 are formed on the inner periphery of the stator core 11. A slot 12 is formed between the teeth 13 adjacent in the circumferential direction of the stator core 11. The stator 10 includes a plurality of coils 30 incorporated in a plurality of slots 12. Here, as shown in FIG. 2, when the length of the teeth 13 along the direction orthogonal to the radial direction of the stator core 11 is the width of the teeth 13, it passes through an intermediate point of the width of the teeth 13, and A straight line extending in the radial direction of the stator core 11 is a center axis TL of the teeth 13. In such a case, the width between the central axes TL of the adjacent teeth 13 is set as the pitch P between the teeth 13. Since the pitch P gradually increases from the tip end of the tooth 13 toward the base end, in this embodiment, the pitch P is the width between the center axes TL at the tip of the teeth 13 and the width between the center axes TL is the largest. Set to a small value.

  Next, the rotor 15 will be described. As shown in FIG. 1, the rotor 15 includes an annular rotor core 16, and the rotor core 16 is configured by laminating a plurality of core plates 161 made of a magnetic material (steel plate). Further, a shaft hole 16a is provided in the center of the rotor core 16, and an output shaft (not shown) of the permanent magnet embedded type rotating electrical machine M is passed through and fixed to the shaft hole 16a.

  As shown by a two-dot chain line in FIG. 1, each virtual region W obtained by equally dividing the rotor core 16 in the circumferential direction (eight divided in the present embodiment) has one first permanent magnet 17 and two second permanents. A magnet 18 is embedded. Each of the first permanent magnet 17 and the second permanent magnet 18 has a flat plate shape, and a cross section orthogonal to the central axis C of the rotor core 16 is formed in a rectangular shape.

  In each virtual region W, one magnetic pole is formed on the rotor core 16 by a set of magnet groups of one first permanent magnet 17 and two second permanent magnets 18. In the present embodiment, the magnet group is arranged at eight locations along the circumferential direction of the rotor core 16, whereby the rotor 15 includes eight magnetic poles, and the plurality of magnetic poles are alternately different in the circumferential direction of the rotor core 16. It is provided to be a magnetic pole. The d-axis 26 shown in FIG. 1 represents the direction of the magnetic flux generated by each magnetic pole (the axis orthogonal to the long side direction of the first permanent magnet 17 and passing between the two second permanent magnets 18), q The shaft 27 represents an axis that is electrically and magnetically orthogonal to the d-axis 26 and extends in an arc shape.

  As shown in FIG. 2, in each virtual region W, a first embedded hole 19 is provided near the outer peripheral surface 16 b of the rotor core 16 in a direction parallel to the central axis C of the rotor core 16. The embedded hole 19 is formed in an elongated shape (rectangular shape) extending substantially along the circumferential direction of the rotor core 16. Specifically, the first embedded hole 19 is formed so that the d-axis is orthogonal to the long side of the first embedded hole 19. The first permanent magnet 17 is inserted into the first embedded hole 19.

  Further, the formation surface of the first embedded hole 19 is opposed to the outer formation surface 19a closer to the outer peripheral surface 16b of the rotor core 16 among the formation surfaces on the long side, and the outer formation surface 19a. And an inner forming surface 19b closer to the inner peripheral surface. And in the 1st permanent magnet 17 inserted in the 1st embedding hole 19, it is an end surface near the outer peripheral surface 16b of the rotor core 16, and the surface facing the outer side formation surface 19a is the magnetic pole surface 17a. The surface that is the end surface closer to the inner peripheral surface of the rotor core 16 and faces the inner forming surface 19b is the anti-magnetic pole surface 17b. Furthermore, in the 1st permanent magnet 17, it is an end surface of both short sides, and the end surface near the q axis | shaft 27 of the 1st permanent magnet 17 is the magnet end surface 17c.

  In each virtual region W (magnetic pole), two second embedded holes 20 having a rectangular shape are formed in the rotor core 16 so that their long sides extend from the inner peripheral surface side of the rotor core 16 toward the outer peripheral surface side. At the same time, it extends so as to extend in a direction parallel to the central axis C. In each virtual region W (magnetic pole), the two second embedded holes 20 are arranged so as to increase in distance from each other toward the outer peripheral surface side from the inner peripheral surface side of the rotor core 16, and are arranged so as to form a V shape. Has been. In each virtual region W (magnetic pole), the two second embedded holes 20 are formed with long sides extending so as to be parallel to (part along) a part of the q-axis 27. A second permanent magnet 18 is fitted in each second embedded hole 20. The formation surface of the second embedded hole 20 is the first formation surface 20a closer to the first embedded hole 19 among the formation surfaces on the long side, and the adjacent magnetic pole facing the first formation surface 20a. The second formation surface 20b closer to the second embedded hole 20 is formed.

  In each virtual region W (magnetic pole), the two second permanent magnets 18 are arranged so that the same side (for example, the outer peripheral surface 16b side of the rotor core 16) has the same polarity. Further, the second permanent magnets 18 arranged on the adjacent magnetic poles are arranged so that the outer peripheral surface 16b side of the rotor core 16 is a different pole. For example, when a set of second permanent magnets 18 is arranged so that the outer peripheral surface 16b side of the rotor core 16 is an S pole, the set of second permanent magnets 18 arranged on the adjacent magnetic poles is the rotor core 16. The outer peripheral surface 16b side is arranged to be N pole. In the present embodiment, in order to allow the rotor 15 to rotate in both forward and reverse directions, the two second permanent magnets 18 are arranged in a line-symmetric position with respect to the d-axis 26.

  A first gap 21 is formed in the rotor core 16 so as to be continuous with both short sides of the first buried hole 19. The rotor core 16 is formed with a second air gap 22 that is separated from the first air gap 21 away from the first permanent magnet 17 and the first air gap 21 toward the q axis 27. Each of the first gap 21 and the second gap 22 extends through the rotor core 16 so as to extend in a direction parallel to the central axis C. In the present embodiment, the first gap 21 and the second gap 22 constitute one gap portion 23.

  The formation surface of the first gap 21 has an outer peripheral side forming surface 21a extending in an arc shape along the outer peripheral surface 16b of the rotor core 16, and from both end edges of the outer peripheral side forming surface 21a from the end on the d-axis 26 side. It has a d-axis side forming surface 21 b extending in parallel with the d-axis 26. The formation surface of the first gap 21 has a formation surface 21c extending in parallel to the magnetic pole surface 17a from the edge of the d-axis side formation surface 21b on the first permanent magnet 17 side toward the q axis 27. An extending surface 21d extending in parallel with the d-axis 26 from the edge of the forming surface 21c is provided. Furthermore, the formation surface of the first gap 21 has a q-axis side formation surface 21e extending from the edge on the q-axis 27 side of the outer peripheral side formation surface 21a toward the inner peripheral surface side of the rotor core 16, and on the q-axis side It has an inner peripheral side forming surface 21f extending from the edge of the forming surface 21e toward the magnet end surface 17c of the first permanent magnet 17. And the formation surface of the 1st space | gap 21 is the outer peripheral side formation surface 21a, the d-axis side formation surface 21b, the formation surface 21c, the extension surface 21d, the q-axis side formation surface 21e, and the inner peripheral side formation surface 21f. It is composed of

  The formation surface of the second gap 22 has an outer peripheral side formation surface 22a extending in an arc shape along the outer peripheral surface 16b of the rotor core 16, and is an end on the d-axis 26 side of both end edges of the outer peripheral side formation surface 22a. A d-axis side forming surface 22b extending in parallel with the q-axis side forming surface 21e of the first gap 21 from the edge is provided. The formation surface of the second gap 22 has a q-axis side formation surface 22d extending along the q-axis 27 from the edge on the q-axis 27 side of the outer peripheral side formation surface 22a.

  In the rotor core 16, a reinforcing bridge 25 is formed between the first gap 21 and the second gap 22. The side surface of the reinforcing bridge 25 on the first space 21 side is formed by the q-axis side forming surface 21e of the first space 21, and the side surface of the reinforcing bridge 25 on the second space 22 side is formed on the d-axis side of the second space 22. It is formed by the surface 22b. The distance between the q-axis side forming surface 21e and the d-axis side forming surface 22b is constant, and the reinforcing bridge 25 is formed with a constant width. The width of the reinforcing bridge 25 is preferably set to be twice or more the thickness of the core plate 161. In each virtual region W (magnetic pole), the reinforcing bridge 25 is formed on the both magnet end surfaces 17 c side of the first permanent magnet 17. The pair of reinforcing bridges 25 are arranged on the inner peripheral surface side from the outer peripheral surface 16 b side of the rotor core 16. It is arranged in the shape of a square that increases the distance between each other.

  In the rotor core 16, an outer peripheral side bridge 24 is formed between the outer peripheral surface 16 b of the rotor core 16 and the outer peripheral side forming surface 21 a of the first gap 21 and the outer peripheral side forming face 22 a of the second gap 22. The outer peripheral bridge 24 is formed to extend with a constant width along the circumferential direction of the rotor core 16, and the width of the outer peripheral bridge 24 is preferably set to be twice or more the thickness of the core plate 161.

  The first gap 21 is formed so as to extend to the outer peripheral surface 16b side from the magnetic pole surface 17a of the first permanent magnet 17, and is formed to extend to the q axis 27 side from the magnet end surface 17c. Here, when the thickness of the first permanent magnet 17 along the d-axis 26 is T, the shortest distance V from the magnet end surface 17c along the direction orthogonal to the d-axis 26 to the q-axis side forming surface 21e is First gap 21 is formed so that 1 / 3T <shortest distance V ≦ T.

  When the shortest distance V is shorter than 1 / 3T, the magnetic pole surface 17a of the first permanent magnet 17 and the reinforcing bridge 25 are close to each other, and the magnetic flux path passing through the reinforcing bridge 25 from the magnetic pole surface 17a is shortened. The resistance becomes small, which is not preferable. On the other hand, when the shortest distance V is shorter than 1 / 3T, the opening width of the first gap 21 is narrowed, and the magnetic flux that is short-circuited from the magnet end surface 17c to the reinforcing bridge 25 increases. On the other hand, if the shortest distance V is longer than the thickness T of the first permanent magnet 17, the first gap 21 becomes too large, making it difficult to suitably set the arrangement of the first gap 21 and the second gap 22 in the magnetic pole. It is not preferable.

  In the first gap 21, when a straight line passing through the extended surface 21d and the magnet end face 17c and extending in parallel with the d-axis 26 is an imaginary line E, the first gap 21 is a base portion closer to the q-axis 27 than the imaginary line E 211 and an extension part 212 extended to the d-axis 26 side from the virtual line E. In the first gap 21, the base 211 is located on the q-axis 27 side from the first permanent magnet 17, and the extension 212 is formed to extend from the base 211 to the d-axis 26.

  The extended portion 212 is formed of a part of the outer peripheral side forming surface 21a closer to the d-axis 26 than the virtual line E, the d-axis side forming surface 21b, and the forming surface 21c. The opening width along the radial direction of the rotor core 16 is such that the extension 212 is narrower than the base 211. Therefore, in the first gap 21, the magnetic flux hardly passes on the base 211 side, and the magnetic flux easily passes through the extended portion 212 having a narrow opening width. For this reason, in the first gap 21, the extension 212 has a smaller magnetic resistance than the base 211.

  Further, in the first gap 21, an inner peripheral side end portion which is a portion located closest to the inner peripheral face of the rotor core 16 in the first gap 21 is formed by the inner peripheral formation surface 21 f. In addition, the outer peripheral side forming surface 21 a of the first gap 21 constitutes an outer peripheral side end portion that is a portion located closest to the outer peripheral face of the rotor core 16 in the first gap 21.

  The magnetic pole surface 17 a of the first permanent magnet 17 is located closer to the inner peripheral surface of the rotor core 16 than the outer peripheral side forming surface 21 a (outer peripheral end) of the first air gap 21, and the inner periphery of the first air gap 21. It arrange | positions so that it may be located in the outer peripheral surface side of the rotor core 16 from the side formation surface 21f. Here, the distance from the outer peripheral surface 16 b of the rotor core 16 along the d-axis 26 to the magnetic pole surface 17 a is the embedded depth of the first permanent magnet 17. In this case, the embedding depth is preferably set to 1 / 10P <embedding depth <2 / 3P, based on the pitch P between the teeth 13.

  When the embedding depth becomes larger than 2 / 3P, the first permanent magnet 17 approaches the inner peripheral surface of the rotor core 16. At this time, since the two second permanent magnets 18 are arranged so as to narrow the distance between the two permanent magnets 18 toward the inner peripheral surface of the rotor core 16, when the first permanent magnet 17 approaches the inner peripheral surface of the rotor core 16, The magnet end surface 17c of the first permanent magnet 17 approaches the second permanent magnet 18, and the short-circuit magnetic flux with the second permanent magnet 18 increases, which is not preferable. On the other hand, when the embedding depth becomes smaller than 1 / 10P, the first permanent magnet 17 approaches the outer peripheral surface 16b of the rotor core 16, and the alternating magnetic field linked to the first permanent magnet 17 increases, resulting in the first The eddy current loss on the surface of the permanent magnet 17 increases, which is not preferable. And the 1st permanent magnet 17 is arrange | positioned so that it may be located between a pair of space | gap part 23 by setting the range of the embedding depth of the 1st permanent magnet 17. FIG.

  The length N of the first permanent magnet 17 in the long side direction is preferably set to 1 to 3 times the pitch P when the pitch P between the teeth 13 is used as a reference. When the length N of the first permanent magnet 17 is shorter than 1 times the pitch P, the magnetic force of the first permanent magnet 17 is lowered, and the magnetic flux generated from the first permanent magnet 17 is decreased, which is not preferable. On the other hand, when the length N of the first permanent magnet 17 is longer than three times the pitch P, the first permanent magnet 17 becomes too long, and the arrangement of the gap 23 and the second permanent magnet 18 in the magnetic pole is suitably set. This is not preferable.

  In each magnetic pole, the distance H between the q-axis side forming surface 22d of each second gap 22 (gap portion 23) and the second permanent magnet 18 adjacent to the q-axis 27 side of the q-axis side forming face 22d is When the pitch P is used as a reference, it is preferably set to 0.3 to 2 times the pitch P. If the distance H is shorter than 0.3 times the pitch P, the magnetic flux passing between the second permanent magnet 18 and the second gap 22 is decreased, which causes a decrease in torque, which is not preferable. On the other hand, if the distance H is longer than twice the pitch P, the magnetic flux passing between the second permanent magnet 18 and the second gap 22 can be increased, but this is not preferable because the torque ripple increases.

Next, the operation of the permanent magnet embedded rotary electric machine M including the rotor 15 will be described.
When the coil 30 is energized, a rotating magnetic field is generated in the stator 10 and a rotating magnetic field acts on the rotor 15. Then, the rotor 15 is rotated by a magnetic attractive force and a repulsive force between the rotating magnetic field and the first permanent magnet 17 and the second permanent magnet 18. At this time, since the first permanent magnet 17 and the second permanent magnet 18 are provided on the rotor core 16, for example, as compared with the case where only the first permanent magnet 17 or the second permanent magnet 18 is provided on the rotor core 16. The reluctance torque is increased by the first and second permanent magnets 17 and 18, and the torque of the permanent magnet embedded rotary electric machine M is increased.

  The centrifugal force generated by the rotation of the rotor 15 causes a force toward the outer peripheral surface 16b of the rotor core 16 to act on the first permanent magnet 17, but the movement of the first permanent magnet 17 is prevented by the reinforcing bridge 25 having mechanical strength. Is done.

  Further, the magnetic flux generated by the rotating magnetic field generated in the stator 10 and the magnetic flux from the magnetic pole surface 17 a of the first permanent magnet 17 are concentrated between the magnet end surface 17 c side of the first permanent magnet 17 and the outer peripheral surface 16 b of the rotor core 16. Then, it is assumed that the energization amount to the coil 30 is increased and a magnetic saturation state is established between the first gap 21 and the outer peripheral surface 16b of the rotor core 16. At this time, by setting the shortest distance V of the first gap 21 within a predetermined range and moving the reinforcing bridge 25 away from the magnet end surface 17c, a magnetic flux path having the reinforcing bridge 25 as a path from the magnetic pole surface 17a of the first permanent magnet 17 can be obtained. It becomes longer and the magnetic resistance becomes larger. For this reason, the short circuit magnetic flux which flows from the magnetic pole surface 17a to the reinforcement bridge 25 is reduced.

According to the above embodiment, the following effects can be obtained.
(1) In the rotor core 16, a gap portion 23 is formed at a position closer to the q axis 27 than the first buried hole 19, and this gap portion 23 is continuous with the first buried hole 19 and is a first permanent magnet. The first gap 21 extends from the magnet end surface 17c of the 17 toward the q-axis 27, and the second gap 22 is separated from the first gap 21 toward the q-axis 27 side. The shortest distance V from the magnet end surface 17c to the q-axis side forming surface 21e of the first gap 21 is set to 1 / 3T <shortest distance V ≦ T with reference to the thickness T of the first permanent magnet 17. The gap 23 is formed so that the reinforcing bridge 25 is separated from the magnet end surface 17c by a predetermined distance. For this reason, it is possible to increase the magnetic resistance in the magnetic flux path from the magnetic pole surface 17a through the reinforcing bridge 25 to the outer peripheral surface 16b or the counter magnetic pole surface 17b of the rotor core 16, and the short-circuit magnetic flux using the reinforcing bridge 25 as a path. Can be reduced. As a result, by moving the reinforcing bridge 25 away from the magnet end face 17c by a predetermined distance, the short-circuit magnetic flux along the path of the reinforcing bridge 25 is reduced while maintaining the mechanical strength without changing the width of the reinforcing bridge 25. In addition, it is possible to prevent a decrease in torque of the permanent magnet embedded rotary electric machine M.

  (2) The width of the reinforcing bridge 25, which is the distance between the q-axis side forming surface 21e of the first gap 21 and the d-axis side forming face 22b of the second gap 22, is at least twice the thickness of the core plate 161. Is set to The first gap 21 and the second gap 22 are formed by punching and removing a predetermined portion of the core plate 161, but the width of the reinforcing bridge 25 is set to be twice or more that of the core plate 161. The strength at the time of punching 161 can be ensured, and deformation of the portion where the reinforcing bridge 25 is formed at the time of punching can be prevented.

  (3) The width of the outer peripheral bridge 24, which is the distance between the outer peripheral surface 16 b of the rotor core 16 and the outer peripheral side forming surface 21 a of the first gap 21 and the outer peripheral side forming surface 22 a of the second gap 22, is the core plate 161. The thickness is set to be twice or more of the thickness. The first gap 21 and the second gap 22 are formed by punching and removing a predetermined portion of the core plate 161, but the width of the outer peripheral bridge 24 is set to be twice or more that of the core plate 161. The strength at the time of punching the plate 161 can be ensured, and deformation at the outer peripheral bridge 24 forming portion at the time of punching can be prevented.

  (4) In each magnetic pole, the pair of reinforcing bridges 25 located on the both magnet end surfaces 17c side of the first permanent magnet 17 is spaced from the outer peripheral surface 16b side of the rotor core 16 toward the inner peripheral surface side. It is arranged in the shape of a broadened C. For this reason, the distance from the magnet end surface 17c to the q-axis side forming surface 21e which is the side surface of the reinforcing bridge 25 is gradually increased from the outer peripheral surface 16b side of the rotor core 16 toward the inner peripheral surface side. Therefore, the magnetic resistance by the 1st space | gap 21 can be enlarged as it goes to the inner peripheral surface side from the outer peripheral surface 16b side of the rotor core 16, and the short circuit magnetic flux to the reinforcement bridge 25 via the 1st space | gap 21 can be reduced. .

  (5) The first air gap 21 is formed to extend from the magnetic pole surface 17a of the first permanent magnet 17 toward the outer peripheral surface 16b of the rotor core 16, and the reinforcing bridge 25 is further away from the magnet end surface 17c by a predetermined distance. ing. For this reason, the magnetic flux from the magnetic pole surface 17 a once flows along the first gap 21 toward the outer peripheral surface 16 b of the rotor core 16 and then flows through the reinforcing bridge 25. Therefore, in addition to securing the shortest distance V, it is possible to increase the magnetic resistance in the magnetic flux path leading to the reinforcing bridge 25, and to further reduce the short-circuit magnetic flux using the reinforcing bridge 25 as a path.

  (6) The first gap 21 includes a base 211 and an extension 212 having a narrower opening width along the radial direction of the rotor core 16 than the base 211. For this reason, in the extension part 212, compared with the base part 211, magnetic flux passes easily and magnetic resistance is small. Therefore, in the rotor core 16, the magnetic resistance gradually decreases from the q-axis 27 toward the d-axis 26 due to the base portion 211 and the extension portion 212, and the rotor 15 is compared with the case where the extension portion 212 is not formed. When the rotor core 16 rotates, the change in the magnetic resistance becomes moderate, and the torque ripple of the permanent magnet embedded rotating electrical machine M can be suppressed.

  (7) In the first permanent magnet 17, the magnetic pole surface 17 a on the outer peripheral surface 16 b side of the rotor core 16 has the inner peripheral surface of the rotor core 16 in the first gap 21 than the outer peripheral side forming surface 21 a on the outer peripheral surface 16 b side of the rotor core 16. It is located on the outer peripheral surface side of the rotor core 16 with respect to the inner peripheral side forming surface 21 f of the first gap 21. In this way, by setting the position of the first permanent magnet 17, even if the first permanent magnet 17 is disposed closer to the outer peripheral surface 16b of the rotor core 16, the first permanent magnet 17 is too close to the outer peripheral surface 16b. Is prevented, and eddy current loss generated on the surface of the first permanent magnet 17 can be suppressed. Further, the first permanent magnet 17 is prevented from being too close to the inner peripheral surface of the rotor core 16, and the short-circuit magnetic flux between the first permanent magnet 17 and the second permanent magnet 18 is reduced.

  Therefore, the temperature rise of the first permanent magnet 17 due to eddy current loss can be suppressed to a small level, the demagnetization of the first permanent magnet 17 can be prevented, and the increase of the short-circuit magnetic flux can be prevented. The torque drop of the magnet-embedded rotating electrical machine M can be prevented. And since the eddy current loss of the 1st permanent magnet 17 can be suppressed, it is not necessary to adopt a magnet having a high coercive force for the first permanent magnet 17, to increase the thickness, or to divide it into a plurality of parts, thereby preventing torque reduction. Therefore, it is possible to avoid an increase in the cost of the first permanent magnet 17 for the purpose.

  (8) Since the embedded depth range of the first permanent magnet 17 is set to 1 / 10P <embedding depth <2 / 3P when the pitch P between the teeth 13 is set as a reference, the embedded permanent magnet type The effect that the eddy current loss can be reduced without reducing the torque of the rotating electrical machine M can be suitably exhibited.

  (9) The length N of the first permanent magnet 17 in the long side direction is preferably set to 1 to 3 times the pitch P when the pitch P between the teeth 13 is used as a reference. By setting the length N of the first permanent magnet 17 in this way, the arrangement of the gap portion 23 and the second permanent magnet 18 in the magnetic pole is prevented while preventing a decrease in magnetic flux due to the first permanent magnet 17 becoming too short. Can be suitably set.

  (10) The interval H between the second gap 22 and the adjacent second permanent magnet 18 is preferably set to 0.3 to 2 times the pitch P when the pitch P is used as a reference. By setting the interval H in this way, it is possible to suppress an increase in torque ripple while suppressing a decrease in torque of the permanent magnet embedded type rotary electric machine M.

  (11) In each magnetic pole, two second permanent magnets 18 are arranged in a V shape so as to extend from the inner peripheral surface side of the rotor core 16 toward the outer peripheral surface 16b side so as to sandwich one first permanent magnet 17. ing. For this reason, in each magnetic pole, the magnetic flux passing through the q-axis 27 can be increased, and the reluctance torque can be increased.

In addition, you may change the said embodiment as follows.
As shown in FIG. 3, the second embedded hole 20 formed in the rotor core 16 is formed in an arc shape extending along the q axis 27 and recessed from the outer peripheral surface side of the rotor core 16 to the inner peripheral surface side. The second permanent magnet 18 fitted into the two embedded holes 20 may be formed by a single permanent magnet having an arc cross section.

  In the embodiment, the two second embedded holes 20 are formed in the rotor core 16 and the second permanent magnets 18 are inserted into the second embedded holes 20, but the second V-shape connected to the rotor core 16 is formed. Two embedded holes 20 may be formed, and one second permanent magnet 18 integrally formed in a V shape may be inserted into the second embedded hole 20, or the second permanent magnet 18 divided into a plurality of parts may be inserted. May be inserted.

  In the embodiment, the pair of reinforcing bridges 25 positioned on the both magnet end surfaces 17c side of the first permanent magnet 17 is configured to increase the distance between the reinforcing bridges 25 from the outer peripheral surface 16b side of the rotor core 16 toward the inner peripheral surface side. However, it may be modified as follows. That is, the pair of reinforcing bridges 25 may be arranged so as to form an inverted C shape that narrows the interval between the reinforcing bridges 25 from the outer peripheral surface 16b side of the rotor core 16 toward the inner peripheral surface side. You may arrange | position so that the space | interval between the reinforcement bridges 25 may become fixed.

The width of the outer peripheral bridge 24 and the reinforcing bridge 25 may be twice or less the thickness of the core plate 161.
In the 1st space | gap 21, the extension part 212 may be formed so that it may become thin gradually as it goes to the d-axis 26 from the base 211. With this configuration, the opening width of the extension portion 212 along the radial direction of the rotor core 16 gradually becomes narrower from the base portion 211 toward the d-axis 26. For this reason, in the rotor core 16, the magnetic resistance gradually decreases from the base portion 211 toward the d-axis 26, and the change in the magnetic resistance in the rotor core 16 can be made more gradual to suppress torque ripple.

  In the embodiment, the first permanent magnet 17 and the two second permanent magnets 18 are arranged in line symmetry with respect to the d-axis 26 so that the embedded permanent magnet rotor 15 rotates in both forward and reverse directions. However, when the embedded permanent magnet rotor 15 is rotated only in one direction, the first permanent magnet 17 and the two second permanent magnets 18 are arranged so as to be axisymmetric with respect to the d-axis 26. May be.

In the embodiment, the number of magnetic poles is eight, but may be changed.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(A) The first gap is composed of a base on the q-axis side from the first permanent magnet and an extension extending from the base to the d-axis, and the extension along the radial direction of the rotor core The embedded permanent magnet rotor according to any one of claims 1 to 9, wherein an opening width of each of the rotors is narrower than an opening width of the base portion.

  H: Spacing, M: Permanent magnet embedded rotary electric machine as a rotary electric machine, N ... Length, P ... Pitch, T ... Thickness, V ... Shortest distance, TL ... Central axis, 10 ... Stator, 11 ... Stator core, DESCRIPTION OF SYMBOLS 13 ... Teeth, 15 ... Embedded permanent magnet rotor (rotor), 16 ... Rotor core, 16b ... Outer peripheral surface, 17 ... First permanent magnet, 17a ... Magnetic pole surface, 17c ... Magnet end surface, 18 ... Second permanent magnet , 19 ... 1st embedding hole, 20 ... 2nd embedding hole, 21 ... 1st space | gap, 21e ... q axis side formation surface as a formation surface of a reinforcement bridge, 21a, 22a ... Outer peripheral side as an outer peripheral side edge part Forming surface, 21f ... Inner circumferential side forming surface as inner circumferential side end, 22 ... Second gap, 22b ... D-axis side forming surface as reinforcing bridge forming surface, 23 ... Gap, 24 ... Outer circumferential side bridge, 25 ... Reinforcement bridge, 26 ... d-axis, 27 ... q-axis, 161 ... Core plate.

Claims (10)

A first embedded hole is formed near the outer peripheral surface of the rotor core inside the stator so as to extend in a direction orthogonal to the d-axis, and a first permanent magnet is embedded in the first embedded hole. A second embedded hole is formed on both sides of the first permanent magnet so as to extend along the q-axis, a second permanent magnet is embedded in the second embedded hole, and the second permanent magnet in the rotor core is further embedded. In a permanent magnet embedded rotor in which a gap is formed at each position closer to the q-axis than one embedded hole,
The gap portion includes a first gap that is continuous with the first embedded hole and extends from the magnet end surface near the q axis of the first permanent magnet toward the q axis, and the q gap side from the first gap. And a reinforcing bridge is formed between the first gap and the second gap, and when the thickness of the first permanent magnet along the d-axis is T, The shortest distance from the end face of the magnet to the formation surface of the reinforcing bridge in the first gap is
1 / 3T <shortest distance ≦ T
The space portion is formed so that,
The gap is a permanent magnet embedded rotor in which the gap is formed so that magnetic flux passes between the second permanent magnet and the gap .   The rotor core is formed by laminating a plurality of magnetic core plates, and the distance between the reinforcing bridge forming surface in the first gap and the reinforcing bridge forming surface in the second gap is: The embedded permanent magnet rotor according to claim 1, wherein the rotor is set to be not less than twice the thickness of the core plate.   Each of the first air gap and the second air gap includes an outer peripheral side forming surface extending along the outer peripheral surface of the rotor core, and between the outer peripheral side forming surface and the outer peripheral surface of the rotor core, along the circumferential direction of the rotor core. 3. The permanent magnet according to claim 2, wherein an outer peripheral bridge that extends is formed, and a distance between the outer peripheral surface and the outer peripheral surface of the rotor core is set to be twice or more the thickness of the core plate. Embedded rotor.   The pair of reinforcing bridges positioned on both magnet end surfaces of the first permanent magnet is formed to have a square shape that increases the distance between the reinforcing bridges from the outer peripheral surface side to the inner peripheral surface side of the rotor core. The embedded permanent magnet rotor according to any one of claims 1 to 3.   The first air gap has an outer peripheral end located near the outermost peripheral surface of the rotor core, and an inner peripheral end located near the innermost peripheral surface of the rotor core, and the first permanent magnet is The magnetic pole surface of the first permanent magnet is located closer to the inner peripheral surface side of the rotor core than the outer peripheral side end portion of the first air gap, and the outer peripheral surface side of the rotor core from the inner peripheral side end portion of the first air gap. The embedded permanent magnet rotor according to any one of claims 1 to 4, wherein the embedded permanent magnet rotor is disposed so as to be positioned at the center. The stator includes a plurality of teeth arranged on the inner periphery of an annular stator core, and a straight line extending along the radial direction of the stator core and passing through an intermediate point in the width direction of the teeth is a central axis of the teeth. When the pitch between the central axes of adjacent teeth is P, the embedded depth of the first permanent magnet from the outer peripheral surface of the rotor core to the magnetic pole surface along the d axis is
1 / 10P <embedding depth <2 / 3P
The embedded permanent magnet rotor according to claim 5, wherein the first permanent magnet is disposed so as to satisfy the above.   The first permanent magnet has a flat plate shape elongated in a direction perpendicular to the d-axis, and the length of the first permanent magnet in the long side direction is set to 1 to 3 times the pitch. Item 7. The permanent magnet embedded rotor according to Item 6.   The embedded permanent magnet rotor according to claim 6 or 7, wherein an interval between the second permanent magnet and the second gap is set to 0.3 to 2 times the pitch.   The said 2nd permanent magnet is arrange | positioned at the V shape extended toward the outer peripheral surface side from the inner peripheral surface side of the said rotor core, or the circular arc shape dented toward the inner peripheral surface side from the outer peripheral surface side of the rotor core. The embedded permanent magnet rotor according to any one of claims 1 to 8. A stator,
A rectangular first embedded hole is formed near the outer peripheral surface of the rotor core inside the stator so as to extend in a direction orthogonal to the d axis, and the first permanent magnet is embedded in the first embedded hole. A second embedded hole is formed on both sides of the first permanent magnet in the rotor core so as to extend along the q axis, and the second permanent magnet is embedded in the second embedded hole; A rotating electric machine comprising a permanent magnet embedded rotor in which a gap is formed at each position closer to the q axis than the first embedded hole in the rotor core,
The rotating electrical machine in which the permanent magnet embedded rotor is the permanent magnet embedded rotor according to any one of claims 1 to 9.

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