JP2012023876A - Permanent magnet rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permanent magnet rotary electric machine capable of preventing short circuit of a field magnetic flux generated by a permanent magnet while securing a mechanical strength, and achieving high torque and high efficiency.SOLUTION: The permanent magnet rotary electric machine includes a stator 2 having armature windings inside a cylindrical core and a rotator 6 rotatably supported inside the stator, where the rotator is made into a magnet embedded rotator in which a plurality of permanent magnets 7 are embedded with equal intervals in a part of a rotator core 5 made of laminated disk-shaped magnetic steel sheets. The rotator core 5 is formed by laminating a first steel plate 51A formed with at least magnet inserting holes 11 to insert the permanent magnets and flux barrier holes 12 at both ends of the magnet inserting holes to prevent magnetic flux short circuiting, and a second steel plate 51B formed with a q-axis hole 13 adjacent to the q-axis in addition to the magnet inserting holes and the flux barrier holes.

Description

  The present invention relates to a permanent magnet type electric motor widely used for home appliances and the like, and more particularly to a permanent magnet type electric rotating machine having a structure suitable for improving mechanical strength as well as magnetic characteristics of a rotor.

  Conventionally, for permanent magnet type electric motors, for example, structures known in Patent Document 1 and Patent Document 2 below have been devised for the purpose of increasing the torque and efficiency of the motor. That is, in particular, according to FIG. 1 of Patent Document 2, the permanent magnet electric motor includes a rotor (10) rotatably attached to a stator (1) that generates a rotating magnetic field through a predetermined gap. ) And a plurality of permanent magnets (11) corresponding to the number of poles are embedded in the rotor (10) along the outer peripheral surface. In order to prevent the magnetic flux generated from the permanent magnet from being short-circuited near the ends of the permanent magnet (11), so-called notches (12a) and (12b) called flux barriers are provided. Furthermore, a rectangular hole (13) is provided on the q-axis of the permanent magnet (11), whereby a stator (d) passing through the d-axis of the permanent magnet (11) is provided. By inhibiting the magnetic flux from 1), the d-axis inductance is reduced, and by ensuring a wide magnetic path of the magnetic flux from the stator passing through the q-axis of the permanent magnet (11), the q-axis inductance is reduced. Therefore, the rotor is configured to generate a reluctance torque of the rotor.

JP 2006-101608 A JP 2000-245087 A

  However, in the structure known from the above-described prior art, in order to generate reluctance torque, it is necessary to set the magnetic path of the q axis as wide as possible. However, in this case, it is generated from the permanent magnet of the rotor. It is conceivable that the field magnetic flux is short-circuited in the rotor without passing through the stator.

  Therefore, the present invention has been achieved in view of the above-described problems in the prior art, and an object of the present invention is to propose a structure for preventing a short circuit of a field magnetic flux generated from a permanent magnet. For that purpose, it is necessary to make the magnetic path between adjacent permanent magnet magnetic poles narrow enough to saturate the magnetic flux by providing a hole on the q axis widely, but in that case, the mechanical strength of the core plate is reduced. Since a problem arises, it is an object of the present invention to propose a novel structure capable of preventing a short circuit of a field magnetic flux generated from a permanent magnet while ensuring its mechanical strength.

  In order to achieve the above object, in the present invention, first, there is a stator provided with an armature winding inside a cylindrical iron core, and a rotor rotatably held inside the stator, In the permanent magnet type rotating electrical machine, wherein the rotor is a magnet-embedded rotor in which a plurality of permanent magnets are embedded at equal intervals in a part of a rotor core formed by laminating disc-shaped electromagnetic steel plates, the rotor core Includes at least a first electromagnetic steel plate in which a magnet insertion hole for inserting the permanent magnet, and a flux barrier hole formed at both ends of the magnet insertion hole for preventing magnetic flux short-circuiting, and the magnet insertion hole In addition to the flux barrier hole, there is further provided a permanent magnet type rotating electrical machine formed by laminating a second electromagnetic steel sheet having a q-axis hole formed in the vicinity of the q-axis.

  Further, in the present invention, in the permanent magnet type rotating electrical machine described above, it is preferable that the rotor core has at least the electromagnetic steel plates laminated at both ends thereof as the first electromagnetic steel plate, and further the rotation In addition to the electromagnetic steel plates laminated at both ends, the core iron core preferably laminates the first electromagnetic steel plate also on a part of other laminated electromagnetic steel plates. And it is preferable to fill the inside of the q-axis hole formed in the second electromagnetic steel plate constituting the rotor core with resin.

  In addition, in the present invention, in the permanent magnet type rotating electrical machine described above, the second electromagnetic steel sheet is formed by the formed q-axis hole, a magnetic path on the outer peripheral side thereof, and the q-axis hole and the q-axis hole The magnetic path formed between the flux barrier holes is narrow enough to saturate the magnetic flux that is short-circuited between adjacent magnetic poles of the plurality of permanent magnets, and the inner peripheral side thereof is the permanent magnet. It is preferably configured to be outside the concentric circle e of the radius obtained by subtracting the thickness of the magnet from the radius of the concentric circle d inscribed in the magnet, or the second electromagnetic steel plate The q-axis hole is divided into a plurality of radial magnetic paths having a width that does not cause magnetic saturation, or the q-axis hole formed in the second electromagnetic steel sheet is adjacent to both sides thereof. Any of the formed flux barrier holes It is also possible to connect to the people.

  In the permanent magnet type rotating electrical machine according to the present invention described above, it is possible to prevent a short circuit of the field magnetic flux generated from the permanent magnet while ensuring the mechanical strength in the rotor core of the rotor. The permanent magnet type rotating electric machine capable of high torque and high efficiency is provided.

It is sectional drawing of the radial direction explaining the whole structure of the permanent magnet type motor which becomes this invention. It is a whole perspective view which shows the detailed structure of the rotor core of the said permanent magnet type electric motor. It is a partially expanded perspective view which shows the detailed internal structure of the iron plate which comprises the said rotor iron core. It is a partially expanded plan view which shows the detailed structure of the 2nd iron plate among the iron plates which comprise the said rotor iron core. It is AA sectional drawing of FIG. 2 which shows the laminated structure of the iron plate which comprises the said rotor core. It is a partially expanded plan view which shows the detailed structure of the 2nd iron plate which comprises the rotor core of the permanent magnet type motor which becomes another Example of this invention. It is a partially expanded plan view which shows the detailed structure of the 2nd iron plate which comprises the rotor core of the permanent magnet type motor which becomes further another Example of this invention.

  Hereinafter, a permanent magnet type rotating electrical machine according to one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  First, FIG. 1 of the accompanying drawings shows a radial cross-sectional structure (cut surface perpendicular to the rotation axis direction) of a permanent magnet type rotating electrical machine according to one embodiment of the present invention. The electric motor 1 includes a stator 2 having a substantially cylindrical appearance, and a rotor 6 having a cylindrical shape in the stator 2 with a predetermined gap between the stator 6 and the inner peripheral surface of the stator. Arranged and rotatably mounted.

  As is apparent from the figure, for example, a plurality of slots 3 are provided in the iron core of the stator 2 in which a plurality of electromagnetic steel plates previously formed in a predetermined shape are laminated, In FIG. 2, concentrated winding armature winding (not shown) is provided, and thereby a rotating magnetic field is generated.

  On the other hand, the rotor 6 includes a rotor core 5 and a rotating shaft 8, and the rotor core 5 has permanent magnets 7 (4 in this example) corresponding to the number of poles. It is embedded at equal intervals along the outer periphery. The rotor core 5 is connected to the rotary shaft 8, and the rotary shaft 8 maintains a predetermined gap between the outer peripheral surface of the rotor core 5 and the inner peripheral surface of the stator 4. It is attached to the stator 4 so as to be rotatable, so that the rotational force is transmitted to the outside via the rotating shaft 8. As is clear from the figure, each of the permanent magnets 7 generates a magnetic field in the radial direction of the core (rotor core 5) constituting the rotor 6, and the adjacent permanent magnets 7 are adjacent to each other. Are arranged so that their polarities are different from each other (reverse polarity). Moreover, the code | symbol 12 in a figure has shown the flux barrier demonstrated also below.

  Next, FIG. 2 attached herewith shows a detailed structure of the rotor core 5 of the permanent magnet type rotating electrical machine described above. As apparent from this figure, the rotor core 5 is configured by laminating a plurality of electromagnetic steel plates (iron plates) 51 formed in a predetermined shape in advance, like the stator 4 described above. The steel plate 51 is formed in an annular shape by, for example, punching processing, and the rectangular magnet insertion hole 11 for inserting the above-described permanent magnet 7 is formed along the outer periphery thereof. In both end portions, holes 12 serving as the flux barrier are formed at positions slightly outside from the magnet insertion holes 11.

  FIG. 3 attached herewith shows a more detailed internal structure of the rotor core 5 described above, that is, a part of a plurality of iron plates 51 constituting the rotor core 5. That is, as shown in the figure, the plurality of iron plates constituting the rotor core 5 are classified into two different types of iron plates 51A and 51B, respectively. First, in the first iron plate 51A, holes 12 serving as the flux barrier are formed at both ends thereof together with the magnet insertion holes 11 described above.

  On the other hand, in the second iron plate 51B, first, the magnet insertion hole 11 and the flux barrier hole 12 formed in the first iron plate 51A described above, and further along the outer periphery thereof, in the vicinity of the q axis. , Q-axis holes 13 are provided.

The details of the q-axis hole 13 are formed between the width d _{O of the} magnetic path formed on the outer peripheral side of the q-axis hole 13 and the hole 12 for the flux barrier, as shown in FIG. The width d _B of the magnetic path is narrow enough to saturate the magnetic flux that is short-circuited between the magnetic poles of adjacent permanent magnets, and the inner peripheral side of the q-axis hole 13 is the radius of the concentric circle d inscribed in the permanent magnet Is preferably outside the concentric circle e having a radius obtained by subtracting the thickness of the magnet (= the width d _M of the magnet insertion hole 11).

  In the present invention, the rotor core 5 is formed by laminating a predetermined number of the two types of core iron plates 51A and 51B described above. For example, the example is shown in FIG. Note that the cross-sectional views shown in these drawings show a cross section along the AA cross section of the rotor core 5 shown in FIG. 2 where the q-axis hole 13 is formed. .

  First, FIG. 5A shows an example in which the above-described two types of core iron plates 51A and 51B are stacked alternately (every other sheet) to form the rotor core 5, and FIG. An example in which two second iron plates 51B are stacked on one first iron plate 51A is shown. In this case, it is preferable to set the iron plates 51A as the iron plates positioned at both ends (upper and lower ends in the figure) of the rotor core 5. Further, in FIG. 5C, the iron plates located at both ends (upper and lower ends of the figure) of the rotor core 5 are used as the first iron plate 51A, and the second iron plate 51B is used as the iron plate located between them. An example was shown.

  As is clear from the above description, in the permanent magnet type rotating electrical machine according to the present invention, in particular, in the rotor core 5, the flux barrier holes 12 become magnetic barriers, and the magnetic flux generated by the permanent magnet 7 is the permanent magnet. Short circuiting around the end of the magnet 7 is suppressed. Furthermore, as described above, the q-axis hole 13 described above is provided in the vicinity of the q-axis in the iron plate 51B among the core iron plates 51A and 51B constituting the rotor core 5. The q-axis hole 13 narrows the magnetic path (width) of the magnetic flux generated by the permanent magnet 7 to the opposite pole of the adjacent permanent magnet 7 so as to be magnetically saturated. Will be suppressed. That is, according to this, it is eliminated that the field magnetic flux generated from the permanent magnet does not pass through the stator and is short-circuited in the rotor (magnetic flux short-circuit prevention effect). High torque and high efficiency of the motor can be achieved.

  Further, as described above, in order to generate reluctance torque, it is desirable to set the q-axis magnetic path as narrow as possible, that is, to set the area of the q-axis hole 13 as wide as possible. In this case, the formation of the q-axis hole 13 decreases the strength of the core iron plate 51B, particularly the strength of the iron plate in the vicinity of the position where the q-axis hole 13 is formed. Therefore, in the present invention, as shown in FIG. 5A or FIG. 5B, the q-axis hole 13 is not formed in all the core iron plates 51, but a part of the second core. The mechanical strength required for the rotor core 5 is ensured by forming the q-axis hole 13 only in the iron plate 51B.

  Alternatively, as shown in FIG. 5C, the iron plate located at both ends (upper and lower ends) of the rotor core 5 is the first iron plate 51A, and the iron plate located therebetween is the second iron plate. When using the iron plate 51B, it is preferable to fill the formed q-axis hole 13 with, for example, an adhesive, a curable resin, or the like. According to this, the resin filled in the q-axis hole 13 can ensure the mechanical strength necessary for the rotor core and can also strengthen the bonding between the core iron plates 51. Further, the mechanical strength of the rotor core can be further enhanced. The filling of the resin into the q-axis hole 13 can be similarly applied to the structure shown in FIG. 5A or 5B.

  According to the permanent magnet type rotating electrical machine according to the embodiment of the present invention described in detail above, the field magnetic flux generated from the permanent magnet is short-circuited in the core iron plate 51 constituting the rotor core. In this case, since it must pass through a magnetic path that is easily magnetically saturated, that is, a magnetic path narrowed by the q-axis hole 13, it is possible to suppress a magnetic flux short circuit in the rotor, that is, to prevent a magnetic flux short circuit. It can be further increased. At that time, not only the second iron plate 51B having a low strength but also the first iron plate 51A having a relatively strong strength is added and laminated alternately to maintain the mechanical strength of the rotor. Furthermore, the mechanical strength of the rotor including the second core iron plate 51B to be stacked can be ensured by filling the q-axis hole 13 with a resin, and therefore, the rotation of the rotor can be achieved while suppressing the magnetic flux short circuit. It becomes possible to achieve both the mechanical strength of the child.

  Furthermore, other embodiments of the present invention, particularly other shapes of the q-axis hole 13 formed in the second core iron plate 51B constituting the rotor, will be described with reference to FIGS. This will be described below.

  First, as is apparent from the drawing, the q-axis hole 13 formed in the core iron plate 51B shown in FIG. 6 is replaced by the q-axis hole 13 shown in FIG. By dividing and providing a magnetic path 13-3 having a width that does not saturate the magnetic flux between them, a decrease in mechanical strength is prevented. That is, according to the q-axis hole 13 having such a shape, the magnetic path formed between the flux barrier hole 12 adjacent to both sides and the q-axis hole 13 is halved. The prevention effect can be further enhanced.

  In FIG. 7, one of a pair of magnetic paths formed between the q-axis hole 13 and the flux barrier holes 12 on both sides of the q-axis hole 13 is cut. It is connected to the q-axis hole 13 to increase the magnetic flux short-circuit prevention effect. In this case as well, it is preferable to fill the inside with, for example, an adhesive, a curable resin, etc., from the viewpoint of ensuring the mechanical strength.

  DESCRIPTION OF SYMBOLS 1 ... Permanent magnet type electric motor, 2 ... Stator, 3 ... Slot, 5 ... Rotor core, 6 ... Rotor, 7 ... Permanent magnet, 8 ... Rotary shaft, 11 ... Magnet insertion hole, 12, 12 '... Flux barrier (Holes), 13, 13-1, 13-2 ... q-axis holes, 13-3 ... narrow magnetic paths, 51, 51A, 51B ... core iron plates.

Claims (7)

A stator provided with armature windings inside a cylindrical iron core;
A rotor rotatably held inside the stator,
In the permanent magnet type rotating electrical machine, the rotor is a magnet-embedded rotor in which a plurality of permanent magnets are embedded at equal intervals in a part of a rotor core formed by laminating disc-shaped electromagnetic steel plates,
The rotor iron core includes at least a first electromagnetic steel plate in which a magnet insertion hole for inserting the permanent magnet and a flux barrier hole formed for preventing magnetic flux short circuit at both ends of the magnet insertion hole; In addition to the magnet insertion hole and the flux barrier hole, a permanent magnet type rotation characterized by being formed by laminating a second electromagnetic steel sheet having a q-axis hole formed in the vicinity of the q-axis. Electric. In the permanent magnet type rotating electrical machine according to claim 1,
The rotor core is a permanent magnet type rotating electrical machine characterized in that at least the electromagnetic steel plates laminated at both ends thereof are the first electromagnetic steel plates. In the permanent magnet type rotating electrical machine according to claim 2,
The rotor core is a permanent magnet type rotating electrical machine wherein the first electromagnetic steel sheet is laminated on a part of another laminated electromagnetic steel sheet in addition to the electromagnetic steel sheets laminated on both ends.   The permanent magnet type rotating electrical machine according to any one of claims 1 to 3, wherein the q-axis hole formed in the second electromagnetic steel sheet constituting the rotor core is filled with a resin. Permanent magnet type rotating electrical machine characterized by In the permanent magnet type rotating electrical machine according to claim 1,
The second electrical steel sheet has a plurality of magnetic paths formed between the q-axis hole and the flux barrier hole by the formed q-axis hole, and a magnetic path formed between the q-axis hole and the flux barrier hole. It is narrow enough to saturate the magnetic flux that is short-circuited between adjacent magnetic poles of the permanent magnet, and its inner peripheral side is obtained by subtracting the thickness of the magnet from the radius of the concentric circle d inscribed in the permanent magnet A permanent magnet type rotating electrical machine characterized by being configured to be outside of a concentric circle e of a radius. In the permanent magnet type rotating electrical machine according to claim 1,
The q-axis hole formed in the second electromagnetic steel sheet is divided into a plurality of radial magnetic paths having a width that does not cause magnetic saturation. In the permanent magnet type rotating electrical machine according to claim 1,
The q-axis hole formed in the second electromagnetic steel sheet is connected to any one of the flux barrier holes formed adjacent to both sides of the q-axis hole.

Images