The present invention described herein relates to a permanent magnet rotor and a permanent magnet synchronous rotating electrical machine.
Patent document 1: Japanese Patent Application Laid-Open Publication No. 2006-121821
Patent document 2: Japanese Patent Application Laid-Open Publication No. 2009-194945
As shown in
Moreover, if rare-earth magnets are used as the permanent magnets, more margin of amount of magnet makes its cost higher.
The present invention has been made to solve the problems described above. The object of the present invention is to lower the costs while ensuring the efficiency of the permanent magnet synchronous rotating electrical machine.
According to the present invention, there is provided a permanent magnet synchronous rotating electrical machine, comprising: a rotor shaft supported rotatably, the rotor shaft extending axially at a rotation axis center; a rotor core in which flux barriers and a flat plate-shaped space are formed, the flux barriers spreading in each circumferential angle region toward the rotation axis center and in a circumferential direction in such a way as to form a convex curved surface and to extend axially, the flat plate-shaped space being located at a circumferential-direction center of the flux barriers, being thinner than radial width of the flux barriers and spreading circumferentially and axially, the rotor core being fixed to the rotor shaft, the rotor core including laminated plates where a plurality of flat steel plates are laminated axially; a flat plate-like permanent magnet provided in such a way as to occupy the flat plate-shaped space; a stator core in which stator teeth are formed, the stator teeth being disposed on an outer surface of the rotor core in such a way as to be away from the rotor core are spaced out circumferentially to each other, the stator teeth extending axially and protruding toward radially inner side; and multi-phase armature windings of multiple poles wound around the stator teeth.
According to the present invention, there is provided a permanent magnet rotor, comprising: a rotor shaft supported rotatably, the rotor shaft extending axially at a rotation axis center; a rotor core in which flux barriers and a flat plate-shaped space are formed, the flux barriers spreading in each circumferential angle region toward the rotation axis center and in a circumferential direction in such a way as to form a convex curved surface and extend axially, the flat plate-shaped space being located at a circumferential-direction center of the flux barriers, being thinner than radial width of the flux barriers and spreading circumferentially and axially, the rotor core being fixed to the rotor shaft, the rotor core including laminated plates where a plurality of flat steel plates are laminated axially; and a flat plate-like permanent magnet provided in such a way as to occupy the flat plate-shaped space.
According to the present invention, it is possible to lower the costs while ensuring the efficiency of the permanent magnet synchronous rotating electrical machine.
Hereinafter, with reference to the accompanying drawings, embodiments of a permanent magnet rotor and a permanent magnet synchronous rotating electrical machine of the present invention will be described. The same or similar portions are represented by the same reference symbols, and a duplicate description will be omitted.
The rotor 10 includes a rotor shaft 11 and a rotor core 12. The rotor shaft 11 extends in the direction of a rotation axis, or extends axially. The rotor core 12 is disposed on a radial periphery out of the rotor shaft 11. The rotor core 12 includes laminated plates which are a plurality of flat steel plates laminated axially. The outer shape of the rotor core 12 is cylindrical. In each circumferential angle region of the rotor core 12, two through-holes 13 (one of them is shown in
In a center region of each through-hole 13, a permanent magnet 51 is provided in such a way as to occupy a corresponding region. In each through-hole 13, in two side regions between which the permanent magnet 51 is located, flux barriers 31 are formed. The permanent magnets 51 are in the shape of a flat plate and extend circumferentially and axially. The permanent magnets 51 are arranged in such a way as to be parallel to each other and spaced out radially to each other.
In the radial direction, the permanent magnets 51 are arranged in such a way that the radially inner permanent magnet 51 and the radially outer permanent magnet 51 have the same polarity. That is, as for the inner permanent magnets 51 and the outer permanent magnets 51, there is a first arrangement by which the radially inner surfaces of both are of N-pole and the radially outer surfaces are of S-pole, or a second arrangement by which the radially inner surfaces of both are of S-pole and the radially outer surfaces are of N-pole. As for the permanent magnets in the circumferential angle regions that are adjacent to each other circumferentially, if one side is in the first arrangement, then the other side is in the second arrangement.
The stator 20 includes a stator core 21 and armature windings 24. The stator core 21 includes laminated plates which are flat plates laminated axially. On the radially inner surface of the laminated plates, stator slots 23 are formed in such away as to face the radially outer surface of the rotor 10 across a gap 25 and extend axially. That is, on the radially inner surface of the stator core 21, stator teeth 22 are formed in such a way as to protrude toward the inner side. Around the stator teeth 22, the armature windings 24 are wound.
The radial direction of both circumferential ends of each circumferential angle region corresponds to q-axis direction, and the radial direction of the circumferential center of each circumferential angle region corresponds to d-axis direction. In
Magnetic flux φ1 is formed in such a way as to pass through the rotor core 12 and the stator core 21, between the permanent magnets 51 of the circumferential direction regions that are adjacent to each other. Accordingly, in the radial direction, magnetic flux φ1 is formed along d-axis. Meanwhile, magnetic flux φ2, which is a reluctance component associated with a rotating magnetic field generated in the stator core 21, is formed along the flux barriers 31 that are formed in the rotor core 12. Accordingly, in the radial direction, magnetic flux φ2 is formed along q-axis.
The center region 13a is formed in such a way that the radially inner surfaces and the radially outer surfaces are parallel to each other, in order to match the shape of the flat-plate permanent magnets 51. As shown in
The radial width of the barrier regions 13b is denoted by D. Width D of the barrier regions 13b is greater than or equal to a width that can ensure a required value of magnetic resistance for the barrier regions 13b to achieve the functionality of the flux barriers 31. As described above, the width d of the center region 13a should be larger than or equal to required thickness d0 but preferably be as small as possible. Meanwhile, the width D of the barrier regions 13b needs to be larger than or equal to required value D0. In general, The value D0 that is required for the width D of the barrier regions 13b is larger than the required thickness d0. Hereinafter, such a general case will be described as an example.
As described above, the center region 13a and the barrier regions 13b are different in width; the latter is larger than the former in width. The through-hole 13 as a whole is in a stepped shape. Groove portions 13c of the barrier regions 13b that are connected to the center region 13a are formed into a smoothly curved surface as shown in
Since the groove portions 13c are formed as the smoothly curved surfaces, the magnetic field lines arising from the permanent magnet 51 are formed with an appropriate density without being squeezed. Moreover, the occurrence of a local magnetic saturation is suppressed. As a result, the distribution of magnetic field lines is optimized, thereby contributing to an improvement in efficiency.
As a result, a magnetic field line that passes near both radial ends of the permanent magnet 51 takes a short path in such a way as to pass through the non-occupied regions 13d, as indicated by dashed line φL1 in
If the distance between an area near the tip of the permanent magnet 51 and the rotor core 12 closest thereto is greater than the width that is required for the flux barriers 31 in the radial direction, a magnetic field line resulting from the area near the tip of the permanent magnet 51 does not pass through the rotor core 12. That is, in such cases as where the two ends of the permanent magnet 51 protrude into the flux barriers 31 as shown in
Therefore, it is preferred that the circumferential-direction length of the permanent magnet be as equal as possible to the circumferential-direction length of the center region 13a of the through-hole 13.
As described above, according to the present embodiment, the formation of a short path of magnetic field lines arising from permanent magnets is suppressed. Moreover, the occurrence of local magnetic saturation is suppressed. Accordingly, a more balanced arrangement of magnetic field lines can be realized. By optimizing the arrangement of magnetic field lines, it is possible to make the magnetic field lines more contribute to the generation of torque. Therefore, the external dimensions of the permanent magnets 51 can be kept to a minimum level required. As a result, it is possible to reduce costs while ensuring the efficiency of the permanent magnet synchronous rotating electrical machine.
Each of the radially inner-side surface of the outer-side filling member 55a and the radially outer-side surface of the inner-side filling member 55b is attached in such a way as to be parallel to each other. After each of the outer-side filling member 55a and the inner-side filling member 55b is attached, the remaining space inside the through-hole 14 is a center region 14a and barrier regions 14b. In the center region 14a, which is located between the surfaces parallel to each other at the center, a permanent magnet 51 (
During the assembly process, after the rotor core 12 is assembled, the outer-side filling member 55a and the inner-side filling member 55b may be attached to the rotor core 12 before the permanent magnet 51 is inserted. Alternatively, the permanent magnet 51 may be mounted before the outer-side filling member 55a and the inner-side filling member 55b are sequentially inserted; or the outer-side filling member 55a, the rotor core 12, and the inner-side filling member 55b may be mounted in this order or in the reverse order.
As described above, according to the present embodiment, the filling members 55 are made of magnetic material. In terms of magnetism, the filling members 55 are small in magnetic resistance as in the rotor core 12, and almost the same magnetic field line distribution as in the first embodiment can be obtained, and almost the same level of efficiency as that of the first embodiment can be ensured. Moreover, the shape of the through-hole 14 formed in the laminated plates is simple, making it easier to process and handle. Moreover, it is possible to ensure a higher level of strength than required.
The present invention is described above by way of several embodiments. However, those embodiments are presented only as examples without any intention of limiting the scope of the present invention.
Those embodiments may be embodied in other various forms. Various omissions, replacements and changes may be made without departing from the subject-matter of the invention.
The above embodiments and variants thereof are within the scope and subject-matter of the invention, and are similarly within the scope of the invention defined in the appended claims and the range of equivalency thereof.
10: rotor, 11: rotor shaft, 12: rotor core, 13: through-hole, 13a: center region, 13b: barrier regions, 13c: groove portion, 13d:non-occupied region, 14:through-hole, 14a: center region, 14b: barrier region, 20: stator, 21: stator core, 22: stator teeth, 23: stator slot, 24: armature windings, 25: gap, 31:lux barrier, 41: permanent magnet, 45: permanent magnet synchronous rotating electrical machine, 51: permanent magnet, 51a: protruding portion, 55: filling member, 55a: outer-side filling member, 55b: inner-side filling member, 100: permanent magnet synchronous rotating electrical machine
Number | Date | Country | Kind |
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2014-197256 | Sep 2014 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2015/004637 | 9/11/2015 | WO | 00 |