rotor

Abstract

A rotor includes: a rotor core including a plurality of one pair of magnet insertion holes in an outer peripheral portion; a first magnet inserted into at least one of the one pair of magnet insertion holes closest to a radial direction inner side of the rotor core in a direction extending toward a radial direction outer side; and a second magnet inserted into a radial direction outer side separately from the first magnet. The at least one of the magnet insertion holes includes, in an inner wall of the rotor core on a radial direction inner side of a gap between the first magnet and the second magnet: a protrusion portion abutting or approaching the first magnet and protruding toward the radial direction outer side to hold the first magnet; and a recessed portion recessed toward the radial direction inner side.

Description

Technical Field

[0001] The technology disclosed in this specification relates to rotors. Background Technology

[0002] A rotor is disclosed, comprising: a rotor core; a magnet inserted into a magnet insertion hole provided in the rotor core; and a molded part holding the magnet within the magnet insertion hole (Japanese Patent Application Laid-Open No. 2024-66577). In this rotor, a pair of magnet insertion holes extending in a V-shape towards the radially outward direction are provided, and multiple magnets are housed in each of the radially extending magnet insertion holes towards the radially outward direction. Summary of the Invention

[0003] The magnet insertion hole has a gap in the molded part around the magnet that is inserted into it, and a protrusion that abuts against the magnet in order to hold and position the magnet.

[0004] However, due to thermal stress during rotor manufacturing and centrifugal force during rotor rotation, stress can sometimes concentrate at specific locations within the magnet insertion hole. Specifically, during thermal expansion of the rotor core and magnets, the magnets are pressed towards the central bridge portion of the magnet insertion hole, thus easily concentrating stress there. It is preferable to prevent the magnets from deforming or breaking due to such stress concentration.

[0005] This specification provides a technique for suppressing stress concentration in the magnet insertion hole of the rotor core, thereby suppressing magnet deformation.

[0006] The technology disclosed in this specification is specifically embodied in a rotor. The rotor comprises: a rotor core having a plurality of pairs of magnet insertion holes on its outer periphery, the pairs of magnet insertion holes extending in a V-shape toward the radially outward; a first magnet, inserted into at least one of the magnet insertion holes in a direction extending toward the radially outward as close as possible to the radially inner side of the rotor core; and a second magnet, inserted separately from the first magnet into the radially outward.

[0007] The magnet insertion hole of at least one of them includes: a protrusion that abuts against or approaches the inner wall of the rotor core radially inward of the gap between the first magnet and the second magnet from the second magnet side, and protrudes outward in the radial direction to retain the first magnet; and a concave portion that is recessed inward in the radial direction from the second magnet side of the protrusion.

[0008] According to the rotor, by providing the concave portion on the second magnet side of the protrusion, deformation of the protrusion is permitted relative to the force acting on the protrusion from the first magnet. Therefore, stress generated in the magnet insertion hole of at least one of the protrusions and stress generated in the first magnet are suppressed respectively. As a result, deformation and damage to the first magnet, etc., can be suppressed.

[0009] In the related technology, there is a tendency for stress to concentrate on the first magnet located near the central bridge portion on the side between the two magnet insertion holes of the pair. However, by providing the concave portion on the second magnet side of the protrusion, it is possible to suppress the stress that tends to concentrate towards the central bridge portion due to the protrusion and the concave portion. Therefore, the stress towards the central bridge portion can be reduced, and a stress balance is achieved between the central bridge portion side and the second magnet side in the first magnet. As a result, as described above, deformation and breakage of the first magnet, etc., can be suppressed. Attached Figure Description

[0010] The features, advantages, technical and industrial significance of embodiments of the present invention are described below with reference to the accompanying drawings, wherein the same reference numerals denote the same elements.

[0011] Figure 1 This is a cross-sectional view showing the magnet insertion hole in the rotor core of the rotor disclosed in this specification and the magnet holding state.

[0012] Figure 2 It is a schematic diagram showing the holding state of a magnet inserted into a hole.

[0013] Figure 3 It is a diagram showing the stress state in the hole into which the magnet is inserted. Detailed Implementation

[0014] The rotor disclosed in this specification (hereinafter also referred to as the rotor) can be used in the following ways in addition to the rotor described herein.

[0015] Another embodiment of this rotor may have the protrusion having a wall-like portion that approaches or abuts the first magnet and protrudes outward in the radial direction. Alternatively, the wall-like portion may have a first surface that approaches or abuts the first magnet and a second surface opposite to the first surface. The concave portion may also be formed with an inner surface shape that recesses inward in the radial direction with the second surface substantially parallel to the first surface. Thus, the concave portion can be formed closest to the protrusion. As a result, stress concentration around the first magnet can be more effectively suppressed in the concave portion.

[0016] Another embodiment of this rotor may also include a retaining member disposed within the magnet insertion hole of at least one of the first and second magnets. Alternatively, the recessed portion may have an inclined portion that is separate from the protrusion and slopes towards the second magnet. This allows for reliable injection and filling of resin into the recessed portion as well, when the retaining member containing resin material is injected and filled into the magnet insertion hole of at least one of the magnets. The inclined portion is advantageous when using a retaining member.

[0017] Alternatively, the rotor may have at least one magnet insertion hole with one or more stress-relieving recesses around the first magnet to mitigate the stress generated on the first magnet. This further suppresses the stress generated on the first magnet.

[0018] Alternatively, the stress-relieving recess can be positioned facing the corner of the first magnet. This effectively relieves the stress at the corner.

[0019] Hereinafter, embodiments of the rotor core disclosed in this specification will be described with appropriate reference to the accompanying drawings. Furthermore, in this specification, "radial direction" refers to the radial direction of the rotor core, "circumferential direction" refers to the circumferential direction of the rotor core, and "axial direction" refers to the axial direction of the rotor core.

[0020] Furthermore, in this specification, the rotor is, for example, an electric generator that functions as an electric motor or a generator. For instance, the rotor, together with itself or an internal combustion engine, can constitute a drive source for a vehicle or the like.

[0021] Figure 1 This shows a section of the rotor 2 disclosed in this specification that is orthogonal to the axial direction of the rotor core 4. Figure 2 This indicates the holding state of magnets 20a and 20b in magnet insertion hole 12. Figure 3 This indicates the stress state of the magnet 20a, etc., inserted into the magnet insertion hole 12. It should be noted that... Figures 1 to 3 It is a sectional view, but the section lines indicating the section are omitted. Figure 1 The retaining member 50 made of resin or the like, which is used to hold the magnet 20 in the magnet insertion hole 12, is omitted.

[0022] like Figure 1 As shown, the rotor 2 includes a rotor core 4 and a plurality of magnets 20 held within the rotor core 4. Figure 1The diagram shows the stator core 6 surrounding the rotor 2, the coils 8 included in the stator core 6, and the frame 10 surrounding the outer periphery of the stator core 6. Additionally, a shaft (not shown) is held at the axial center of the rotor core 4 via a bearing 2a. The axial end face and the other end face of the rotor core 4 may also be clamped by end plates (not shown) or the like.

[0023] The rotor core 4 is not particularly limited, and may be formed, for example, by stacking electromagnetic steel plates made of magnetic materials such as iron or iron alloys along the axial direction.

[0024] The rotor core 4 has multiple sets of pairs of magnet insertion holes 12, 14. More specifically, the rotor core 4 has multiple sets of pairs of magnet insertion holes 12, 14 extending in a V-shape towards the radially outward direction along the circumferential direction. For example, there are eight sets of pairs of magnet insertion holes 12, 14. The magnet insertion holes 12, 14 extend from the radially inward side towards the radially outward side, forming the left and right sides of the V-shape respectively, separated by the central bridge portion 15.

[0025] The V-shape formed by the magnet insertion holes 12 and 14 is not particularly limited. The V-shape can be configured to extend linearly from the inner side of the radial direction to the outer side of the radial direction, or it can be formed as follows: Figure 1 It bends and expands as shown.

[0026] The magnet insertion holes 12 and 14 are formed to pass through the rotor core 4 along the axial direction. Two magnets 20 (hereinafter referred to as 20a and 20b in the radial direction from the inside) are respectively held in the magnet insertion holes 12.

[0027] Here, the magnets 20a and 20b held in the magnet insertion hole 12 will be described. Magnets 20a and 20b are not particularly limited; for example, known permanent magnets can be used. Magnets 20a and 20b each have an elongated shape extending along the axial direction. Furthermore, the cross-sections of magnets 20a and 20b orthogonal to the axial direction are, for example, as shown below. Figure 1 As shown, it has a rectangular or other quadrilateral shape. Furthermore, magnets 20a and 20b are examples of the first and second magnets disclosed in this specification.

[0028] Figure 1 The magnet insertion holes 12 and 14 shown have a structure that is symmetrical about left and right with the middle part, namely the central bridge part 15, so the magnet insertion hole 12 will be described below.

[0029] Insert the magnet into hole 12, such as Figure 1 and Figure 2As shown, magnets 20a and 20b are arranged sequentially from the inner to the outer side in the radial direction. More specifically, the long end faces corresponding to the long sides of the cross-sections of each magnet 20a and 20b are maintained in an outwardly extending direction along the magnet insertion hole 12 in the radial direction. Magnets 20a and 20b are separated within the magnet insertion hole 12 by a predetermined gap 18. Figure 1 In the middle, the magnet insertion hole 12 has a curved shape extending outward in the radial direction, so the gap 18 has an inner surface shape that bends or folds between the two magnets 20a, 20b.

[0030] like Figure 2 As shown, a retaining member 50 is provided in the magnet insertion hole 12 to fill the space between the magnets 20a and 20b and the inner wall of the magnet insertion hole 12. The retaining member 50 is not particularly limited, but it can be any structure that has a certain fluidity and can be injected into the gap between the magnets 20a, etc., and the inner wall of the magnet insertion hole 12, and can fill the gap by hardening, for example, through heat treatment. For example, the retaining member 50 can contain a resin material such as a thermosetting resin or a thermoplastic resin.

[0031] The inner wall 16 of the magnet insertion hole 12 has a shape suitable for holding magnets 20a and 20b. For example... Figure 2 As shown, the inner wall portion 16 of the magnet insertion hole 12 has stress-relieving recesses 24, 26, 28, 30, and 32. The stress-relieving recesses 24, 26, 28, 30, and 32 are all formed to extend axially.

[0032] Stress-relieving recesses 24, 26, and 28 are provided around the magnet 20a to alleviate stress caused by thermal stress and centrifugal force. Thermal stress is sometimes generated during the manufacturing of the rotor 2, such as during the injection of the retainer 50, heat treatment, and welding of the laminated steel plates of the rotor core 4. In addition, centrifugal force is sometimes generated during the rotation of the rotor 2.

[0033] The stress-relieving recess 24 is formed near the center bridge portion 15 of the magnet 20a and faces the long end face near the corner L1 in the radial direction. The stress-relieving recess 26 is formed facing the short end face of the magnet 20a corresponding to the short side L2 located at the innermost radial side. In addition, a holding portion 25 is formed between the stress-relieving recess 24 and the stress-relieving recess 26. This holding portion 25 abuts against or approaches the short end face near the corner L1 of the magnet 20a, thereby enabling the magnet 20a to be held and positioned.

[0034] The stress-relieving recess 28 is located at a distance from the central bridge portion 15 of the magnet 20a and is formed facing the long end face near the inner corner L3 in the radial direction. The stress-relieving recesses 24, 26, and 28 are all formed in a concave shape facing the inside of the rotor core 4 in a manner that depicts a gentle curved surface, which can relieve the stress around the magnet 20a.

[0035] Stress-relieving recesses 30 and 32 are provided around the magnet 20b to alleviate stress caused by the various reasons described above. The stress-relieving recess 30 is located at a distal position relative to the central bridge portion 15 of the magnet 20b and faces the long end face near the inner corner L4 in the radial direction. The stress-relieving recess 32 is formed facing the short end face corresponding to the outermost short side L5 of the magnet 20b in the radial direction. Both the stress-relieving recesses 30 and 32 are formed concavely towards the interior of the rotor core 4 in a manner depicting a gently curved surface, thus mitigating the stress around the magnet 20b.

[0036] like Figure 1 and Figure 2 As shown, the gap 18 between magnets 20a and 20b has a protrusion 34 capable of holding magnet 20a. The protrusion 34 is formed on the inner wall portion 18a of the gap 18 in the radial direction. The protrusion 34 has a wall-like portion 35, which can abut or approach the short end face L6 of magnet 20a within a predetermined range from the corner portion L3 of magnet 20a from the outer radial direction or the magnet 20b side to hold and position magnet 20a.

[0037] The wall-like portion 35 has a surface 36 facing the short end face L6 and a surface 38 on the opposite side of surface 36. Surface 38 protrudes towards the magnet 20b through the gap 18. Surfaces 36 and 38 are substantially parallel, and the wall-like portion 35 becomes a wall-like body of substantially constant thickness. The height and thickness of the wall-like portion 35 are only required to function as a protrusion 34; for example, its thickness can be set to a range of 0.3 mm or more and 2 mm or less. Furthermore, surfaces 36 and 38 are examples of the first and second surfaces disclosed in this specification, respectively.

[0038] The magnet insertion hole 12 has a concave portion 40. The concave portion 40 is disposed adjacent to the magnet 20b side of the protrusion 34. The concave portion 40 is formed in the magnet insertion hole 12 in a recessed manner from the inner wall portion 18a toward the radially inward side, that is, in a manner that is separate from the protrusion 34 and the inner wall portion 18a.

[0039] Unlike the stress-relieving recesses 24, 26, 28, 30, and 32, the concave portion 40 is not a significantly curved concave shape, but rather roughly formed into a narrow groove. This effectively allows for the deformation of the protrusion 34, suppressing stress concentration around the magnet 20a. For example, as... Figure 2 As shown, the concave portion 40 is formed with an inner surface shape in which a surface 38, which is substantially parallel to the surface 36 of the wall-like portion 35, is recessed inward in the radial direction. Therefore, the concave portion 40 can be formed closest to the protrusion 34. This allows for effective deformation of the protrusion 34, and the concave portion 40 enables good stress concentration around the magnet 20a.

[0040] like Figure 1 and Figure 2 As shown, the concave portion 40 has an inclined portion 42 that is separated from the protrusion 34 and inclined toward the magnet 20b side. The inclined portion 42 is inclined in such a way that the opening of the concave portion 40 expands toward the magnet 20b side. Therefore, when the retainer 50 is injected, the concave portion 40 can be easily filled with the retainer 50.

[0041] The shape and size of the concave portion 40 are not particularly limited, as long as they allow for the deformation of the protrusion 34 and suppress stress concentration around the magnet 20a. For example, the inner wall portion 18a can have a groove-shaped opening within a width of about 0.3 mm to 2 mm.

[0042] Furthermore, an additional pair of magnet insertion holes 60, 62 and magnets may be provided inside the V-shape of the magnet insertion holes 12, 14 of the rotor core 4 and further outside in the radial direction. Additionally, an appropriate number of cooling medium flow paths 70, 72 may be provided circumferentially inside the magnet insertion holes 12, 14 in the radial direction.

[0043] The stress concentration suppression effect in the magnet insertion hole 12 of such rotor 2 will be explained. Figure 3 The upper section shows the state of the magnet insertion hole 12' having the same structure as described above except that it does not have the concave portion 40, while the lower section shows the state of the magnet insertion hole 12' having the concave portion 40.

[0044] like Figure 3 As shown in the previous paragraph, in the conventional magnet insertion hole 12', there is a tendency for stress concentration to occur near the short end face corresponding to the short side L2 of the magnet 20a due to the various factors mentioned above.

[0045] In contrast, such as Figure 3 As shown in the next section, the rotor core 4 has a concave portion 40, which serves as a kind of weak point, allowing deformation of the protrusion 34. By allowing deformation of the protrusion 34, for example, during thermal expansion of the rotor core 4 and the magnet 20a, the amount of displacement of the short side L2 of the magnet 20a towards the central bridge portion 15 is suppressed. Therefore, the stress near the short end face corresponding to the short side L2 of the magnet 20a can be reduced. As a result, stress concentration around the magnet 20a can be suppressed, and deformation of the magnet 20a can be suppressed. At the same time, stress concentration towards the central bridge portion 15 is suppressed, so the central bridge portion 15 can be narrowed, and the maximum rotational speed of the rotor 2 can be increased.

[0046] In the above embodiments, the concave portion 40 is formed in a groove shape on the magnet 20b side adjacent to the protrusion 34 holding the magnet 20a. Therefore, deformation of the protrusion 34 can be effectively allowed, and stress concentration around the magnet 20a can be more effectively suppressed. Furthermore, in the above embodiments, the magnet insertion holes 12 and 14 of the rotor 2 have the same structure. However, a portion of the magnet insertion holes 12 and 14 of the rotor 2, or at least one of the magnet insertion holes 12 and 14, may also have a concave portion 40.

[0047] Furthermore, the concave portion 40 of the rotor core 4 has an inclined portion 42. Therefore, when the retainer 50 made of resin material is injected around the magnet 20a and so on and cured, the retainer 50 is easily filled in the concave portion 40, which can improve the filling performance of the retainer 50.

[0048] It should be noted that, in addition to the concave portion 40, the rotor core 4 has stress-relieving concave portions 24, 26, 28, 30, and 32 in the magnet insertion hole 12, so the rotor core 4 can be used to disperse the stress generated under various conditions.

[0049] In the above embodiments, the concave portion 40 is formed with an inner surface shape in which a surface 38, which is substantially parallel to the surface 36 of the wall portion 35, is recessed toward the radial direction, but it is not limited to this. The concave portion 40 may also have an inner surface shape in which the surface 38 slopes from the top of the wall portion 35 in a manner that gradually separates from the surface 36 and is recessed toward the radial direction.

[0050] Furthermore, in the above embodiments, stress-relieving recesses 24, 26, 28, 30, and 32 are provided, but at least some of them may also be provided. The structure of the stress-relieving recesses can be modified as needed.

[0051] Furthermore, while the above embodiments use a retainer 50 containing resin material, it is not a limitation. Various other known retaining units may be used appropriately.

[0052] This instruction manual, based on the above description, includes the following items.

[0053] [1] A rotor comprising: a rotor core having a plurality of pairs of magnet insertion holes on its outer periphery, the pairs of magnet insertion holes extending in a V-shape toward the radially outward side; a first magnet being inserted into at least one of the magnet insertion holes in a direction extending toward the radially outward side as close as possible to the radially inward side of the rotor core; and a second magnet being inserted separately from the first magnet into the radially outward side, the at least one magnet insertion hole comprising: a protrusion that abuts against or approaches the inner wall of the rotor core on the radially inward side of the second magnet side and the gap between the first magnet and the second magnet, and protrudes toward the radially outward side to retain the first magnet; and a recess that is recessed toward the radially inward side of the second magnet side of the protrusion.

[0054] [2] According to the rotor of [1], the protrusion has a wall-like portion that approaches or abuts the first magnet and protrudes outward in the radial direction, the wall-like portion has a first surface that approaches or abuts the first magnet and a second surface that is opposite to the first surface, and the concave portion is formed to have an inner surface shape that is recessed inward in the radial direction in a manner that the second surface is substantially parallel to the first surface.

[0055] [3] The rotor according to [1] or [2] further comprises a retaining member disposed in the magnet insertion hole of at least one of the first magnets and the second magnets around the first magnet and the second magnet, the concave portion having an inclined portion that is separated from the protruding portion and inclined toward the second magnet side.

[0056] [4] The rotor according to any one of [1] to [3], wherein the magnet insertion hole of at least one of them also has one or more stress-relieving recesses around the first magnet to relieve the stress generated in the first magnet.

[0057] [5] According to the rotor described in [4], the stress-relieving recess is provided in such a way that it faces the corner of the first magnet.

[0058] The above details specific examples of the technology disclosed in this specification, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes technologies obtained by various modifications and alterations to the specific examples described above. The technical elements illustrated in this specification or drawings exert their technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of application. The technology illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful.

Claims

1. A rotor comprising: The rotor core has a plurality of pairs of magnet insertion holes on its outer periphery, the pairs of magnet insertion holes extending outward in a V-shape toward the radial direction; The first magnet is inserted into at least one of the pair of magnet insertion holes, along a direction extending outward in the radial direction, most closely inward in the radial direction of the rotor core; and The second magnet is inserted separately from the first magnet into the outer radial direction. The magnet insertion hole of at least one of them includes: a protrusion that abuts against or approaches the inner wall of the rotor core radially inward of the gap between the first magnet and the second magnet from the second magnet side, and protrudes outward in the radial direction to retain the first magnet; and a concave portion that is recessed inward in the radial direction from the second magnet side of the protrusion.

2. The rotor according to claim 1, wherein, The protrusion has a wall-like portion that approaches or abuts the first magnet and protrudes outward in the radial direction. The wall-like portion has a first surface that approaches or abuts the first magnet and a second surface opposite to the first surface. The concave portion is formed with an inner surface shape that is recessed inward in the radial direction in a manner that the second surface is substantially parallel to the first surface.

3. The rotor according to claim 1, wherein, The rotor further includes a retaining member disposed within the magnet insertion hole of at least one of the magnets, surrounding the first magnet and the second magnet. The concave portion has an inclined portion that is separate from the protruding portion and tilts toward the second magnet side.

4. The rotor according to any one of claims 1 to 3, wherein, The magnet insertion hole of at least one of them also has one or more stress-relieving recesses around the first magnet to alleviate the stress generated by the first magnet.

5. The rotor according to claim 4, wherein, The stress-relieving recess is positioned so as to face the corner of the first magnet.

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