Embedded magnet type rotor and rotary electric machine

Abstract

To provide an embedded magnet type rotor capable of simplifying a manufacturing process and a rotary electric machine.SOLUTION: An embedded magnet type rotor includes: a rotor core in which a plurality of magnet housing holes is formed; a permanent magnet; two magnet restraining members 100 that are disposed on both sides in an axial direction of the rotor core and restrain a plurality of permanent magnets; and two restraining plates 50 that are disposed on both outer sides in the axial direction and restrain the rotor core and the magnet restraining members 100 in the axial direction. The permanent magnet is housed in each of the plurality of magnet housing holes and has first and second side surfaces whose long sides in a cross section extend in the axial direction and third and fourth side surfaces whose short sides in a cross section extend in the axial direction. The magnet restraining member 100 has an axial direction restraining unit 120 for restraining the permanent magnet in the axial direction of the rotor core and a lateral direction restraining unit 120 for restraining the permanent magnet in a direction perpendicular to the axial direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an interior permanent magnet rotor and a rotating electric machine. [Background technology]

[0002] In an embedded magnet rotor, unlike a surface magnet rotor, a permanent magnet is disposed inside the rotor core. To accommodate the magnet, a magnet storage hole is formed in the rotor core along the axial direction. For this reason, punching is performed to form the magnet storage hole in each of the laminated electromagnetic steel sheets. As the embedded magnet rotor rotates, centrifugal force is applied to the permanent magnet, so that the permanent magnet is pressed radially outward in the magnet storage hole. Also, when the rotor is stopped, gravity is applied, pressing the permanent magnet vertically downward. For this reason, it is necessary to restrain the movement of the permanent magnet in the magnet storage hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3757434 [Patent Document 2] Japanese Patent Application Publication No. 9-182334 [Patent Document 3] JP 2011-109786 A Summary of the Invention [Problem to be solved by the invention]

[0004] FIG. 10 is a partial cross-sectional view showing a conventional example of a magnet housing hole of an interior magnet type rotor.

[0005] According to the conventional example, magnet holding protrusions 4a, 4b that restrict radial inward and radial outward movement of the permanent magnets 5 are formed in the magnet storage holes 4 that house the respective permanent magnets 5 in the rotor core 3. In addition, recesses 4c, 4d are formed to reduce stress concentration at the bases of the magnet holding protrusions 4a, 4b.

[0006] In this way, the shape of the magnet storage hole 4 is complicated, and the jigs used to punch out each electromagnetic steel sheet are complicated. Also, if it is difficult to punch out the magnetic steel sheet to the final shape in one go, the process may be divided into multiple goes, complicating the procedure.

[0007] One method to avoid forming such complicated storage holes is to fix the permanent magnet 5 with an adhesive. However, the method of fixing with an adhesive requires dedicated equipment for applying the adhesive, and there is a problem in that handling the adhesive requires a high burden of managing the temperature, amount of application, curing conditions, etc.

[0008] Furthermore, as another method, a method of restraining the permanent magnet 5 from its end in the axial direction is known. Fig. 11 is a partial vertical cross-sectional view conceptually showing a conventional example of a method for restraining the permanent magnet 5 in an interior magnet rotor. In this conventional example, a restraining member 8 having a tapered portion 8t is provided on the end side of the permanent magnet 5. The permanent magnet 5 is guided by the tapered portion 8t of the restraining member 8, and the permanent magnet 5 is positioned and restrained by tightening the restraining member 8 from the outside to the inside in the axial direction.

[0009] Here, since the permanent magnet 5 is generally a sintered material, it is fragile and prone to chipping or damage in the areas where it comes into contact with other members. In the conventional example shown in Fig. 11, the corners 5x of the permanent magnet 5 come into contact with the tapered portions 8t of the restraining member 8, and a diagonal load is applied to the side surfaces. In addition, stress tends to be concentrated in the areas where they come into contact, which raises concerns that partial chipping may occur. Even if a slope is formed at the corners of the permanent magnet 5, the same concerns remain.

[0010] The above problems occur not only in the case of a rotor core in which electromagnetic steel sheets are laminated, but also in the case of a rotor core in the form of a single unit.

[0011] An object of the present invention is to provide an interior permanent magnet rotor and a rotating electric machine that can simplify the manufacturing process and reduce the possibility of damage to the permanent magnets. [Means for solving the problem]

[0012] In order to achieve the above-mentioned object, an embodiment of the present invention provides an embedded magnet type rotor comprising: a rotor core having a plurality of magnet storage holes formed therein; a permanent magnet stored in each of the plurality of magnet storage holes, the permanent magnet having a rectangular cross section with first and second side faces whose long sides extend in the axial direction and third and fourth side faces whose short sides extend in the axial direction; two magnet restraint members arranged on both axial sides of the rotor core to restrain the plurality of permanent magnets; and two restraint plates arranged on both axial outsides of the two magnet restraint members to restrain the rotor core and the two magnet restraint members from both axial sides, the magnet restraint members having an axial restraint portion that restrains the permanent magnet in the axial direction of the rotor core, and a lateral restraint portion that restrains the permanent magnet in a direction perpendicular to the axial direction. [Brief description of the drawings]

[0013] [Figure 1] 1 is a vertical sectional view showing a rotating electric machine according to a first embodiment. [Diagram 2] 2 is a partial cross-sectional view showing a magnet storage hole of the embedded magnet rotor according to the first embodiment. FIG. [Diagram 3] FIG. 2 is a perspective view showing a magnet restraining member and a retainer plate of the embedded magnet rotor according to the first embodiment. [Figure 4] 2 is a cross-sectional view taken along line AA showing a part of a protruding portion of a magnet restraining member of the embedded magnet rotor according to the first embodiment. FIG. [Diagram 5] 4 is a partial cross-sectional view showing a first modified example of the magnet restraining member of the embedded magnet rotor according to the first embodiment. FIG. [Figure 6] 13 is a partial cross-sectional view showing a second modified example of the magnet restraint member of the embedded magnet rotor according to the first embodiment. FIG. [Figure 7] FIG. 11 is a partial cross-sectional view showing a magnet restraining member of an embedded magnet rotor according to a second embodiment. [Figure 8]FIG. 11 is a partial cross-sectional view showing a modified example of the magnet restraining member of the embedded magnet rotor according to the second embodiment. [Figure 9] FIG. 11 is a perspective view showing a magnet restraining member of an embedded magnet rotor according to a third embodiment. [Figure 10] FIG. 1 is a partial cross-sectional view showing a conventional example of a magnet housing hole of an embedded magnet type rotor. [Figure 11] FIG. 1 is a partial vertical cross-sectional view conceptually showing a conventional example of a method for constraining permanent magnets in an embedded magnet type rotor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an interior permanent magnet rotor and a rotating electric machine according to an embodiment of the present invention will be described with reference to the drawings. Here, the same or similar parts are given the same reference numerals and duplicated explanations will be omitted.

[0015] [First embodiment] FIG. 1 is a vertical cross-sectional view showing a rotating electric machine 10 according to the first embodiment.

[0016] The rotating electric machine 10 includes an interior permanent magnet rotor 1, a stator 12, and a housing 14 that houses the stator 12.

[0017] The embedded magnet type rotor 1 has a rotor shaft 2 rotatably supported by bearings 13 and extending in the direction of the rotation axis CL, a rotor core 15 attached to the radial outside of the rotor shaft 2, a permanent magnet 5 housed within the rotor core 15, a magnet restraint member 100 that holds the permanent magnet 5, and a retaining plate 50 that holds the rotor core 15 and the magnet restraint member 100 from both outside in the axial direction.

[0018] Stator 12 has stator core 12a disposed radially outside rotor core 15 so as to surround rotor core 15, and stator winding 12b wound around stator core 12a.

[0019] FIG. 2 is a partial cross-sectional view showing magnet storage hole 16 of interior magnet rotor 1 according to the first embodiment.

[0020] The permanent magnet 5 is, for example, a rectangular parallelepiped shape, and has four side surfaces, a first side surface 5a, a second side surface 5b, a third side surface 5c, and a fourth side surface 5d, and two rectangular end surfaces 5e. The first side surface 5a and the second side surface 5b are short sides that are opposite to each other and parallel to each other in the cross section of FIG. 2. The third side surface 5c and the fourth side surface 5d are long sides that are opposite to each other and parallel to each other in the cross section of FIG. 2. Note that, in FIG. 2, the first side surface 5a and the second side surface 5b, and the third side surface 5c and the fourth side surface 5d that face each other are shown as being parallel to each other, but this is not limited thereto, and each may have a shape that has an angle with respect to each other.

[0021] The magnet storage hole 16 in this embodiment does not have the magnet holding protrusions 4a, 4b formed in the magnet storage hole 4 of the conventional example shown in Fig. 10. That is, the storage hole outer wall surface 16a, which is the radially outer wall surface of the magnet storage hole 16 in this embodiment, and the storage hole inner wall surface 16b, which is the radially inner wall surface, are flat and have no irregularities. Also, when the permanent magnet 5 is rectangular as shown in Fig. 2, the storage hole outer wall surface 16a and the storage hole inner wall surface 16b are formed parallel to each other.

[0022] FIG. 3 is a perspective view showing the magnet restraint member 100 and the retainer plate 50 of the embedded magnet rotor 1 according to the first embodiment.

[0023] 3 shows magnet constraint member 100 and retainer plate 50, which is shown by hatching overlapping therewith, viewed from one outside in the axial direction. In FIG. 3, rotor core 15, not shown, is disposed below magnet constraint member 100.

[0024] The magnet restraint member 100 has a flat plate portion 101, a lateral restraint portion 110, and an axial restraint portion 120. In the example shown in FIG. 3, the magnet restraint member 100 is formed as a single unit. That is, the flat plate portion 101, the lateral restraint portion 110, and the axial restraint portion 120 are connected to one another as a single unit. The magnet restraint member 100 may be formed, for example, by punching out a single disk and deforming the out-of-plane portions, i.e., the lateral restraint portion 110 and the axial restraint portion 120, out-of-plane by, for example, press working. Alternatively, if the length of these out-of-plane portions is insufficient as a result of punching, another member may be connected to the deformed portion by, for example, welding.

[0025] The flat plate portion 101 of the magnet restraint member 100 is a roughly circular plate with irregularities on the periphery. In other words, the plate has a shape with eight protrusions 101a on the outer periphery corresponding to the magnetic poles. In addition, the eight recesses 101b have rod through holes 106 formed in every other recess, i.e., in four locations. In the center of the flat plate portion 101, a central hole 105 through which the rotor shaft 2 passes is formed.

[0026] Each of the eight protruding portions 101a of the flat plate portion 101 is formed with a lateral restraint portion 110 and an axial restraint portion 120 for holding two permanent magnets 5 that constitute a magnetic pole. The lateral restraint portion 110 and the axial restraint portion 120 are each formed so as to be outside the plane of the flat plate portion 101.

[0027] On the other hand, the pressing plate 50 is a generally circular plate having an uneven periphery. Specifically, it has eight protrusions 50a and eight recesses 50b. Each protrusion 50a of the pressing plate 50 is arranged so as to face the recess 101b of the flat plate portion 101 of the magnet restraint member 100. The eight protrusions 50a of the pressing plate 50 have rod through holes 56 formed in every other one of the eight protrusions 50a, i.e., in four locations. A central hole 55 through which the rotor shaft 2 passes is formed in the center of the pressing plate 50.

[0028] When the flat plate portion 101 and the pressure plate 50 are in a concentric state, the rod through holes 106 of the flat plate portion 101 and the rod through holes 56 of the pressure plate 50 are arranged concentrically. The diameter of the rod through holes 56 of the pressure plate 50 is formed to be equal to or smaller than the diameter of the rod through holes 106 of the flat plate portion 101. It is preferable that they are formed to be the same diameter. When the embedded magnet type rotor 1 is in an assembled state, a rod (not shown) passes through each of the rod through holes 106, 56. For example, a screw is formed in the rod near the end in the axial direction, and the laminated electromagnetic steel plates and magnet restraint member 100 constituting the rotor core 15 can be fastened from both sides via the pressure plate 50 with a nut.

[0029] In addition, in Figure 3, the embedded magnet type rotor 1 is shown as an example in which there are eight magnetic poles (8 poles) arranged on the convex portion 101a indicated by the dashed lines, but this is not limited to this and it is sufficient if there are two or more magnetic poles.

[0030] Fig. 4 is a cross-sectional view taken along line AA showing a part of the protruding portion 101a of the magnet constraint member 100 of the embedded magnet rotor 1 according to the first embodiment. Fig. 4 shows the lateral constraint portion 110 and the axial constraint portion 120 of the protruding portion 101a, i.e., one of the two permanent magnets 5 that constitute the magnetic pole.

[0031] The flat plate portion 101 of the magnet restraint member 100 extends in a direction parallel to the end face 5 e of the permanent magnet 5 .

[0032] The axial restraint portion 120 protrudes from the flat plate portion 101 and is in contact with an end face 5 e of the permanent magnet 5 .

[0033] Each lateral restraint portion 110 has two contact portions 111 and two bent portions 112. The two contact portions 111 are bent by the bent portions 112 from the flat portion 101 in a direction perpendicular to the flat portion 101 so as to face each other. The two contact portions 111 are formed so as to be in close contact with the first side surface 5a and the second side surface 5b of the permanent magnet 5.

[0034] FIG. 5 is a partial cross-sectional view showing a first modified example of the magnet restraint member 100a of the embedded magnet rotor 1 according to the first embodiment.

[0035] In the magnet constraint member 100a of the first modification, the bent portion 112a of the lateral constraint portion 110a is curved outward. As a result, it is possible to avoid interference between the lateral constraint portion 110a and the permanent magnet, regardless of the protruding height of the axial constraint portion 120 out of the plane. In addition, it becomes easier to adjust the pressure of the two contact portions 111 when they contact the first side surface 5a and the second side surface 5b of the permanent magnet 5.

[0036] FIG. 6 is a partial cross-sectional view showing a second modified example of the magnet restraint member 100b of the embedded magnet rotor 1 according to the first embodiment.

[0037] The lateral restraining portion 110b of the magnet restraining member 100b in the second modification has a contact portion 111b, a bent portion 112, a bent portion 112b, and a guide portion 113b on both sides.

[0038] The contact portion 111b is curved outward by two bends, the bend 112 and the bend 112b. As a result, similar to the first modification, it is possible to avoid interference between the lateral restraint portion 110b and the permanent magnet, regardless of the protruding height of the axial restraint portion 120 out of the plane. In addition, it becomes easier to adjust the pressure when the two contact portions 111 are in contact with the first side surface 5a and the second side surface 5b of the permanent magnet 5.

[0039] The contact portion 111 of the lateral restraint portion 110b makes line contact with the permanent magnet 5, not surface contact. Furthermore, a guide portion 113b is provided on the tip side of the contact portion 111. As a result, the magnet restraint member 100b can be easily fitted to each permanent magnet 5. Furthermore, even if the distance between the two opposing contact portions 111b is set to be smaller than the width of the permanent magnet 5, i.e., the distance between the first side surface 5a and the second side surface 5b, as a state before fitting with the permanent magnet 5, the fitting is possible. As a result, the clamping force applied to the permanent magnet 5 by the two contact portions 111b can be increased.

[0040] In addition, while Figures 4 to 6 above show cases where the lateral restraint portions 110, 110a, 110b act on the first side surface 5a and the second side surface 5b of the permanent magnet 5 to restrain the permanent magnet 5, they may also act on the third side surface 5c and the fourth side surface 5d of the permanent magnet 5 to restrain the permanent magnet 5.

[0041] As described above, the lateral restraint portion 110b of the magnet restraint member 100 according to this embodiment restrains the permanent magnet 5 by clamping the side surfaces of the permanent magnet 5. The axial direction is also restrained perpendicular to the end faces. In other words, the load applied is perpendicular to each face and is basically a compressive stress, and even if a shear force occurs, the proportion of this is small. For this reason, unlike the conventional example shown in FIG. 11, where the corners of the permanent magnet 5 are restrained by tapered portions, a diagonal load is not applied to the side surfaces and the shear force does not increase, and a structure with less stress concentration is obtained.

[0042] Furthermore, by using magnet constraint member 100 according to this embodiment, there is no need to provide rotor core 15 with a portion for holding permanent magnets 5, simplifying the structure of magnet storage hole 16. As a result, the manufacturing process can be simplified.

[0043] [Second embodiment] 7 is a partial cross-sectional view showing a magnet constraint member 100c of an embedded magnet rotor 1 according to a second embodiment. This embodiment is a modification of the first embodiment. In this embodiment, the storage hole outer wall surface 16a and the storage hole inner wall surface 16b are used to constraint the permanent magnet 5.

[0044] Each of the lateral restraining portions 110c has a contact portion 111c that contacts the magnet and a wall contact portion 114 that contacts the wall surface (the storage hole outer wall surface 16a or the storage hole inner wall surface 16b). It also has a curved portion 112 and a guide portion 113c.

[0045] In this way, by utilizing the wall surface, it is possible to ease the condition of ensuring the rigidity of the curved portion 112 in order to secure the force for sandwiching the side surface of the permanent magnet 5. Also, the adjustable range of the rigidity of the lateral restraint portion 110c is expanded, allowing it to be set to a more appropriate rigidity.

[0046] 8 is a partial cross-sectional view showing a modified magnet restraint member of the embedded magnet rotor 1 according to the second embodiment. In the modified magnet restraint member 100d, the guide portion 113d has a bent structure, and a wall contact portion 114d is provided at the tip side of the guide portion 113d. By adopting such a structure, it is possible to widen the range of adjustment of rigidity. Also, in the case of the magnet restraint member 100d, the wall contact portion 114 is located axially outboard of the contact portion 111c, whereas in this modified example, it is possible to widen the range of selection of the axial positional relationship between the contact portion 111d and the wall contact portion 114d.

[0047] [Third embodiment] FIG. 9 is a perspective view showing a magnet restraint member 100f of the embedded magnet rotor 1 according to the third embodiment.

[0048] This embodiment is a modification of the first embodiment. A magnet restraint member 100f of this embodiment has an axial restraint portion 120f instead of the axial restraint portion 120 of the first embodiment. Other than this, this embodiment is similar to the first embodiment.

[0049] The axial restraint portion 120f in this embodiment extends in one direction from the flat plate portion 101 and is bent out of the plane, and the tip is not connected to the flat plate portion 101. One end is bent out of the plane, and then the intermediate portion is returned so as to be approximately parallel to the flat plate portion 101.

[0050] The extending direction of axial restraint portion 120f is different by 90 degrees from the extending direction of axial restraint portion 120 in the first embodiment, but may be the same direction as that of axial restraint portion 120. Also, the connection portion with flat plate portion 101 and the tip portion may be reversed from that shown in FIG.

[0051] In the axial restraint portion 120f in this embodiment, since it acts as a cantilever spring, the rigidity is much easier to adjust compared to a case in which both ends are restrained as in the axial restraint portion 120. Also, conversely, if the rigidity of the axial restraint portion 120 is too large, there is a possibility that out-of-plane deformation will occur in the flat plate portion 101 around the portion to which the axial restraint portion 120 is joined, but in the case of the axial restraint portion 120f in this embodiment, such a problem can be eliminated.

[0052] According to the embodiments described above, it is possible to provide an interior permanent magnet rotor and a rotating electric machine that can simplify the manufacturing process and reduce the possibility of damage to the permanent magnets.

[0053] [Other embodiments] Although the embodiments of the present invention have been described above, the embodiments are presented as examples and are not intended to limit the scope of the invention. In addition, the features of each embodiment, for example, the features of the second embodiment and the features of the third embodiment, may be combined. Furthermore, the embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. The embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and gist of the invention. [Explanation of symbols]

[0054] REFERENCE SIGNS LIST 1...embedded magnet rotor, 2...rotor shaft, 3...rotor core, 4...magnet storage hole, 4a, 4b...magnet holding protrusions, 4c, 4d...recesses, 5...permanent magnet, 5a...first side, 5b...second side, 5c...third side, 5d...fourth side, 5e...end face, 5x...corner, 6...end plate, 8...restraint member, 8t...tapered portion, 10...rotating electric machine, 12...stator, 12a...stator core, 12b...stator winding, 13...bearing, 14...casing, 15...rotor core, 16...magnet storage hole, 16a...outer wall surface of storage hole, 16b...inner wall surface of storage hole, 50...retainer Plate, 50a...convex portion, 50b...concave portion, 55...central hole, 56...rod through hole, 100, 100a, 100b, 100c, 100d, 100f...magnet restraining member, 101...flat plate portion, 101a...convex portion, 101b...concave portion, 105...central hole, 106...rod through hole, 110, 110a, 110b...lateral restraining portion, 111, 111b, 111c, 111d...contact portion, 112, 112a, 112b, 112c...bent portion, 113b, 113c, 113d...guide portion, 114, 114c...wall surface contact portion, 120, 120f...axial restraining portion

Claims

1. A rotor core having a plurality of magnet housing holes formed therein; a permanent magnet housed in each of the magnet housing holes, the permanent magnet having a rectangular cross section and a first side surface and a second side surface whose longer sides extend in the axial direction and a third side surface and a fourth side surface whose shorter sides extend in the axial direction; two magnet restraining members arranged on both sides of the rotor core in the axial direction and restraining the plurality of permanent magnets; two presser plates that are disposed on both axial outer sides of the two magnet restraint members and press the rotor core and the two magnet restraint members from both axial sides; Equipped with an embedded magnet type rotor, characterized in that the magnet restraint member has an axial restraint portion that restrains the permanent magnet in the axial direction of the rotor core, and a lateral restraint portion that restrains the permanent magnet in a direction perpendicular to the axial direction.

2. 2. The interior magnet type rotor according to claim 1, wherein the magnet restraining member is formed as a single piece.

3. 2. The interior magnet rotor according to claim 1, wherein the lateral restraint portion restrains the first side surface and the second side surface, or the third side surface and the fourth side surface.

4. 4. The embedded magnet type rotor according to claim 1, wherein the axial restraint portion protrudes outward from a surface of the magnet restraint member with both ends connected thereto.

5. 4. The embedded magnet rotor according to claim 1, wherein the axial restraint portion protrudes outward from a surface of the magnet restraint member with only one end connected thereto.

6. The embedded magnet rotor according to claim 1 ; a stator disposed radially outside the rotor core via a gap so as to surround the rotor core; A rotating electric machine comprising:

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