rotor

Abstract

A rotor of a motor capable of considering mechanical strength and narrowing a magnetic bridge width is provided. A rotor (20) of the present application includes a first bonded magnet (MG1) having a first long side (LS1), a second bonded magnet (MG2) having a second long side (LS2), and a rotor core (22) that houses the first bonded magnet (MG1) and the second bonded magnet (MG2). The rotor core (22) includes a pair of first hole portions (41) that are provided so as to sandwich a first magnetic bridge (B1) on a d-axis on a radially outer side and house the first bonded magnet (MG1), and a pair of second hole portions (42) that are provided so as to sandwich a second magnetic bridge (B2) on the d-axis on a radially inner side and house the second bonded magnet (MG2). A minimum width (H1) of the first magnetic bridge (B1) is 10% or less of a length of the first long side (LS1), and a minimum width (H2) of the second magnetic bridge (B2) is 30% or less of a length of the second long side (LS2) of the second bonded magnet (MG2) on the d-axis side.

Description

Technical Field

[0001] This invention relates to a rotor for a motor. Background Technology

[0002] Patent Document 1 discloses a rotor that is concentrically arranged inside the stator in a rotatable manner, forming a plurality of magnetic poles arranged circumferentially around the q-axis. The rotor includes: a rotor core, which, in units of magnetic poles, has multiple layers of magnet-filling holes arranged radially and symmetrically around the d-axis; and magnets disposed within the magnet-filling holes. The rotor core has: a first magnetic bridge portion contained in the multiple layers of radially arranged magnet-filling holes, disposed between a pair of adjacent first magnet-filling holes around the d-axis; and a magnet located in the... The second magnetic bridge portion, located radially inward of the first magnet filling hole and positioned between a pair of adjacent second magnet filling holes sandwiching the d-axis; the third magnetic bridge portion, positioned between the outer circumferential surface of the rotor core and the first magnet filling hole; and the fourth magnetic bridge portion, positioned between the outer circumferential surface of the rotor core and the second magnet filling hole, satisfy the relationship L3 < L1 < L4 < L2 when the minimum width of the first magnetic bridge portion is set to L1, the minimum width of the second magnetic bridge portion is set to L2, the minimum width of the third magnetic bridge portion is set to L3, and the minimum width of the fourth magnetic bridge portion is set to L4.

[0003] Furthermore, in Patent Document 1, the above-described structure enables the provision of a rotor with mechanical strength that corresponds to the high-speed rotation of a rotary electric motor.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2023-102517

[0005] On the other hand, the magnetic bridge section becomes a magnetic circuit for leakage flux, so there is a requirement to minimize its width as much as possible. Summary of the Invention

[0006] The present invention was made in view of such circumstances, and one object is to provide a rotor for a motor that takes mechanical strength into account and narrows the width of the magnetic bridge.

[0007] The rotor of the present invention is a motor rotor, comprising: a plurality of first adhesive magnets arranged in units of magnetic poles; a plurality of second adhesive magnets arranged in units of magnetic poles; and a rotor core that houses the first adhesive magnets and the second adhesive magnets. The first adhesive magnets have a cross-section having a first long side and a first width in a direction orthogonal to the first long side; the second adhesive magnets have a cross-section having a second long side and a second width in a direction orthogonal to the second long side; the rotor core comprises: a pair of first holes symmetrically arranged to sandwich a first magnetic bridge located on the radially outer d-axis, and housing the first adhesive magnets; and a pair of second... The first hole portion has two holes, which are symmetrically arranged to sandwich the second magnetic bridge located on the d-axis on the radially inner side, and each hole portion houses a plurality of the second adhesive magnets. The first hole portion has a first placement hole portion for placing the first adhesive magnets and a first gap portion on one side disposed between the first placement hole portion and the first magnetic bridge. The second hole portion has a second placement hole portion for placing the second adhesive magnets and a second gap portion on one side disposed between the second placement hole portion and the second magnetic bridge. The minimum width of the first magnetic bridge is 10% or less of the length of the first long side, and the minimum width of the second magnetic bridge is 30% or less of the length of the second long side of the second adhesive magnet on the d-axis side.

[0008] According to the present invention, it is possible to provide a rotor for a motor that takes into account mechanical strength and narrows the width of the magnetic bridge. Attached Figure Description

[0009] Figure 1 This is a cross-sectional view of a motor using a rotor according to an embodiment of the present invention.

[0010] Figure 2 This is a schematic cross-sectional view of a rotor according to an embodiment of the present invention.

[0011] Figure 3 It is amplified by Figure 2 A magnified detailed view of the area enclosed by the dotted lines.

[0012] Explanation of reference numerals in the attached figures

[0013] 1…Motor, 20…Rotor, 22…Rotor core, 41…First hole, 41A…First configuration hole, 41B…First gap on one side, 42…Second hole, 42A…Second configuration hole, 42B…Second gap on one side, 42B1…Extending wall, 42B2…Extended wall, 42B3…R wall, B1…First magnetic bridge, B2…Second magnetic bridge, CA…Arc-shaped wall, H1…Minimum width of the first magnetic bridge, H2…Minimum width of the second magnetic bridge, LS1…First long side, LS2…Second long side, MG1…First adhesive magnet, MG2…Second adhesive magnet, P…Position, SS1…First short side, SS2…Second short side (second side). Detailed Implementation

[0014] Hereinafter, the forms for carrying out the present invention (hereinafter referred to as "implementation") will be described in detail with reference to the accompanying drawings.

[0015] Furthermore, in the overall description of the embodiments, the same components are labeled with the same numbers or reference numerals.

[0016] In addition, the scale of the attached drawings differs from the actual scale. They are drawn only for ease of understanding and explanation, and it is not guaranteed that the same parts in the attached drawings are drawn at the same size.

[0017] Furthermore, in the accompanying drawings, for ease of observation, sometimes only a portion of multiple parts with the same properties are labeled with reference to the accompanying drawings.

[0018] <Implementation Method>

[0019] Reference Figures 1-3 The rotor 20 of the motor 1, which is used to illustrate an embodiment of the present invention, is described below.

[0020] Furthermore, the motor 1 using the rotor 20 of this embodiment is suitable for use as a rotary motor for driving automobiles, but it can also be used as a motor for other applications.

[0021] Figure 1 This is a cross-sectional view of a motor 1 using the rotor 20 according to an embodiment of the present invention, and is a cross-sectional view along the long side of the rotor shaft 21.

[0022] Furthermore, in the following, the direction of the long side of the rotor shaft 21, which will become the rotating shaft, will be described as the axial direction, the direction along the rotation direction of the rotor shaft 21 will be described as the circumferential direction, and the direction on the plane orthogonal to the axial direction will be described as the radial direction.

[0023] In addition, in the radial direction, the side away from the rotor shaft 21 is described as the radial outer side, and conversely, the side close to the rotor shaft 21 is described as the radial inner side.

[0024] like Figure 1As shown, motor 1 is an internal rotor type motor, and rotor 20 in this embodiment is a rotor that can be suitably used in an internal rotor type motor.

[0025] The motor 1 of this embodiment includes: a stator 10; a rotor 20 arranged radially inside the stator 10 in a manner that allows it to rotate relative to the stator 10; and a housing 30 for housing the stator 10 and the rotor 20.

[0026] Furthermore, the rotor shaft 21 of the rotor 20 is rotatably mounted on the housing 30 via bearings 40 (ball bearings in this example) at both ends, thereby configuring the rotor 20 as a component that can rotate relative to the stator 10.

[0027] In addition, the housing 30 has: on one side of the axial direction ( Figure 1 The left side of the main body 31 has an opening and a bottomed cylindrical body 31, and a cover 32 that blocks the opening of the main body 31.

[0028] Specifically, the main body 31 has a portion at the bottom 31A on the other side where the rotor shaft 21 is disposed. Figure 1 The rotor shaft 21 is supported by a bearing 40 at the right end of the rotor shaft 21 through hole 31AH, at which the rotor shaft 21 is rotatable.

[0029] In addition, the rotor shaft 21 can also be configured to extend outward from the housing 30 through the through hole 31AH at the bottom 31A.

[0030] In addition, the cover 32 has a recess 32A that receives one end of the rotor shaft 21, where the rotor shaft 21 is supported by the bearing 40 to be able to rotate.

[0031] [Stator 10]

[0032] The stator 10 includes: a cylindrical stator core 11 with multiple slots (not shown), and a stator coil 12 wound in the slots of the stator core 11.

[0033] For example, the stator core 11 can be a stacked core formed by stacking electromagnetic steel plates along the axial direction, or it can be a pressed powder core formed by stamping metal powder.

[0034] Furthermore, the ends of the stator coil 12, i.e. the coil ends, are located at both ends of the stator core 11 along the axial direction.

[0035] [Rotor 20]

[0036] Figure 2 This is a schematic cross-sectional view of the rotor 20 according to an embodiment of the present invention. Figure 1 A sectional view along line AA.

[0037] Right now, Figure 2 It is a schematic diagram showing a cross section orthogonal to the axial direction of the rotor 20.

[0038] like Figure 1 As shown, the rotor 20 includes: a rotor shaft 21 that serves as the axis of rotation, and a shaft hole 22A in the center for mounting the rotor shaft 21 (see reference). Figure 2 The cylindrical rotor core 22 and the end plates 23 disposed at both ends of the rotor core 22 along the axial direction.

[0039] Alternatively, end plate 23 can be omitted.

[0040] In addition, rotor 20 is equipped with: according to each magnetic pole ( Figure 2 The rotor core 22 houses the first adhesive magnets MG1 (in the area between the q axes), the second adhesive magnets MG2 (as opposed to each magnetic pole), and the first adhesive magnets MG1 and the second adhesive magnets MG2.

[0041] (Rotor shaft 21)

[0042] like Figure 1 As shown, the rotor shaft 21 is a hollow cylindrical shape that allows refrigerant to flow inward, and has release holes for releasing refrigerant toward the coil ends of the stator coils 12 located at both ends of the stator core 11 along the axial direction.

[0043] In addition, while oils such as ATF are preferred as refrigerants, water, for example, can also be used.

[0044] In addition, in this embodiment, the rotor shaft 21 is shown as a cylindrical component having a hollow portion that forms a refrigerant flow path, but the rotor shaft 21 may also be a solid cylindrical component.

[0045] (First adhesive magnet MG1)

[0046] The first bonding magnet, MG1, is, for example, a samarium iron nitrogen magnet (SmFeN magnet) with a density of 4.5 g / cm³. 3 Above, 6.5g / cm 3 The following magnets generally have a density ratio of 7.4 g / cm³. 3 The above are examples of low-density magnets such as neodymium (Nd) magnets.

[0047] Moreover, such as Figure 2 As shown, the first adhesive magnet MG1, as a cross-section orthogonal to the axial direction, has a cross-section with a generally quadrilateral shape having a first long side LS1 and a first short side SS1.

[0048] In this embodiment, the cross-section of the first adhesive magnet MG1 orthogonal to the axial direction is rectangular, so the length of the first width in the direction orthogonal to the first long side LS1 is the same as the length of the pair of first short sides SS1 connecting the pair of first long sides LS1.

[0049] For example, as an example, the first adhesive magnet MG1 has a first long side LS1 with a length of 11.5 mm and a first short side SS1 (first width) with a length of 4 mm.

[0050] In addition, the first adhesive magnet MG1 is sometimes chamfered (about 0.3mm C chamfer) at the corners to eliminate burrs, forming a roughly quadrilateral shape (rectangle).

[0051] In this case, we only need to extend a first long side LS1 and a pair of first short sides SS1, and take the length between the intersection points of the extensions of the first long side LS1 and the pair of first short sides SS1 as the length of the first long side LS1.

[0052] In addition, in order to facilitate the removal of the first adhesive magnet MG1 from the molding die when the first adhesive magnet MG1 is formed, sometimes the cross section orthogonal to the axis of the first adhesive magnet MG1 is a roughly quadrilateral shape with a pair of sides that are inclined inwards at about a few degrees (e.g., about 3 degrees) relative to the bottom.

[0053] In this case, the bottom base can be regarded as the first long side LS1. Furthermore, when the corners are beveled, the length between the pair of sides connecting the bottom base and the top base and the bottom base can be extended, and the length between the intersection points of the bottom base and the pair of sides can be regarded as the length of the first long side LS1.

[0054] (Second adhesive magnet MG2)

[0055] The second bonding magnet MG2 is the same as the first bonding magnet MG1, and is a samarium iron nitrogen magnet (SmFeN magnet) with a density of 4.5 g / cm³. 3 Above, 6.5g / cm 3 The following magnets generally have a density ratio of 7.4 g / cm³. 3 The above are examples of low-density magnets such as neodymium (Nd) magnets.

[0056] Moreover, such as Figure 2 As shown, the second adhesive magnet MG2, as a cross-section orthogonal to the axial direction, also has a cross-section with a generally quadrilateral shape having a second long side LS2 and a second short side SS2.

[0057] In addition, Figure 2In the middle, although the second long side LS2 of the second adhesive magnet MG2 located on the radial outer side is depicted as longer than the second long side LS2 of the second adhesive magnet MG2 located on the radial inner side, in reality, both sides have the same length of second long side LS2.

[0058] However, the second long side LS2 and the second short side SS2 of the second adhesive magnet MG2 on the radially outer side and the second adhesive magnet MG2 on the radially inner side are not necessarily limited to the same length.

[0059] In this embodiment, the cross-section of the second adhesive magnet MG2 orthogonal to the axial direction is rectangular, so the length of the second width in the direction orthogonal to the second long side LS2 is the same as the length of the pair of second short sides SS2 connecting the pair of second long sides LS2.

[0060] For example, as an example, the second adhesive magnet MG2 is the same as the first adhesive magnet MG1, having a second long side LS2 with a length of 11.5 mm and a second short side SS2 (second width) with a length of 4 mm.

[0061] Furthermore, the second adhesive magnet MG2 is the same as the first adhesive magnet MG1, and is sometimes a roughly quadrilateral shape (rectangular) with the corners chamfered (C chamfer of about 0.3mm) to eliminate burrs.

[0062] In this case, it is sufficient to extend one of the second long sides LS2 and the pair of second short sides SS2, and regard the length between the intersection points of the extensions of the second long side LS2 and the pair of second short sides SS2 as the length of the second long side LS2.

[0063] In addition, sometimes, in order to facilitate the removal of the second adhesive magnet MG2 from the molding die when the second adhesive magnet MG2 is formed, the cross section orthogonal to the axis of the second adhesive magnet MG2 is a roughly quadrilateral shape with a pair of sides that are inclined inwards at about a few degrees (e.g., about 3 degrees) relative to the bottom.

[0064] In this case, the bottom base can be regarded as the second long side LS2. And when the corner is beveled, the length between the pair of sides connecting the bottom base and the top base and the bottom base can be extended, and the length between the intersection points of the bottom base and the pair of sides can be regarded as the length of the second long side LS2.

[0065] (Rotor core 22)

[0066] like Figure 1 As shown, in this embodiment, the rotor core 22 is a stacked core formed by stacking electromagnetic steel plates along the axial direction, but it can also be a pressed powder core formed by stamping metal powder.

[0067] Moreover, such as Figure 2As shown, the rotor core 22 has a pair of first holes 41 that are symmetrically arranged with respect to the first magnetic bridge B1 located on the radially outer d axis, each hole being a unit of magnetic poles (the area between the q axes). These holes accommodate the first adhesive magnet MG1.

[0068] In addition, such as Figure 2 As shown, a pair of first holes 41 are V-shaped, opening radially outward from the radially inner end on the d-axis side toward the radially outer side.

[0069] Furthermore, each pair of first holes 41 includes: a first placement hole 41A for placing the first adhesive magnet MG1, a first gap 41B disposed on one side between the first placement hole 41A and the first magnetic bridge B1, and a first gap 41C disposed on the other side radially outward.

[0070] In addition, the first gap 41B on one side and the first gap 41C on the other side function as magnetic flux barriers to reduce the leakage flux of the first adhesive magnet MG1.

[0071] In addition, such as Figure 2 As shown, the rotor core 22 has a pair of second holes 42 that are symmetrically arranged with respect to the second magnetic bridge B2 located on the radially inner d axis, each hole housing a plurality of second adhesive magnets MG2 (in this example, two second adhesive magnets MG2) on the magnetic pole (the area between the q axes).

[0072] In addition, such as Figure 2 As shown, the pair of second holes 42 as a whole are formed into a U-shape that opens radially outward by forming an inner V-shaped part that opens radially outward at a large angle from the radially inner end on the d-axis side and an outer V-shaped part that opens radially outward at a small angle from the inner V-shaped part to the radially outer side.

[0073] However, the inner V-shape and the outer V-shape can also open radially outward at the same angle, forming a V-shape that opens radially outward as a whole.

[0074] Furthermore, a second adhesive magnet MG2 is housed in both the inner V-shaped portion on the radially inner side and the outer V-shaped portion on the radially outer side.

[0075] Specifically, each of the pair of second holes 42 includes: a pair of second placement holes 42A for placing the second adhesive magnet MG2, a second gap 42B disposed on one side between the second placement hole 42A and the second magnetic bridge B2, and a second gap 42C disposed on the other side radially outward.

[0076] In addition, each of the pair of second holes 42 also has an intermediate gap 42D provided between the pair of second configuration holes 42A, and the opening angle that opens radially outward changes at the intermediate gap 42D.

[0077] Furthermore, the second gap 42B on one side, the second gap 42C on the other side, and the middle gap 42D function as magnetic flux barriers to reduce the leakage flux of the second adhesive magnet MG2.

[0078] However, if the rotor 20 rotates, the stress will be concentrated on the first magnetic bridge B1 and the second magnetic bridge B2 due to centrifugal force. But if the mass of the first adhesive magnet MG1 and the second adhesive magnet MG2 is large, the stress will increase.

[0079] Specifically, if the mass of the first bonding magnet MG1 is large, there is a tendency for the stress applied to the first magnetic bridge B1 to increase; if the mass of the second bonding magnet MG2 is large, there is a tendency for the stress applied to the second magnetic bridge B2 to increase.

[0080] Therefore, in this embodiment, considering the relationship with the first adhesive magnet MG1 and the second adhesive magnet MG2, the widths of the first magnetic bridge B1 and the second magnetic bridge B2 are set to be relatively narrow. This will be explained in detail below.

[0081] Figure 3 It is an amplification of the original text. Figure 2 A magnified detailed view of the area enclosed by the dotted lines in AR.

[0082] "First Magnetic Bridge B1"

[0083] like Figure 3 As shown, the first gap 41B, which is symmetrically arranged on one side of the d-axis, has a shape that curves slowly toward the d-axis side, and the first magnetic bridge B1 has a minimum width H1.

[0084] Furthermore, the minimum width H1 of the first magnetic bridge B1 is less than 10% of the length L11 (not shown) of the first long side LS1 [(H1 (mm) / L11 (mm))×100 (%)≤10 (%)], specifically, the minimum width H1 of the first magnetic bridge B1 is 0.8 mm (approximately 7% of the length of the first long side LS1).

[0085] The minimum width H1 can be set to such a small size because the density of the first adhesive magnet MG1 is low, which reduces the mass of the first adhesive magnet MG1 that affects stress.

[0086] In addition, the first gap 41B on one side has a shape that bends toward the d-axis, which not only prevents the formation of a sharp edge on the first magnetic bridge B1 where stress is easily concentrated, but also disperses the stress, thereby further preventing damage to the first magnetic bridge B1.

[0087] Moreover, although the first magnetic bridge B1 becomes the magnetic circuit for the leakage flux of the first adhesive magnet MG1, the ease of flux flow depends on the minimum width H1 of the first magnetic bridge B1.

[0088] Therefore, compared to the conventional structure, as long as the rotor 20 of this embodiment can reduce the minimum width H1 of the first magnetic bridge B1, the leakage flux of the first adhesive magnet MG1 can be suppressed to a lower level.

[0089] On the other hand, it is preferable that the minimum width H1 of the first magnetic bridge B1 is more than 6% of the length L11 (not shown) of the first long side LS1 [(H1 (mm) / L11 (mm))×100 (%)≥6 (%)], so as to ensure sufficient strength of the first magnetic bridge B1 and further avoid damage to the first magnetic bridge B1.

[0090] Furthermore, due to the size of the first adhesive magnet MG1 installed on the rotor 20, the width of the first short side SS1 (i.e., the first width in the direction orthogonal to the first long side LS1) cannot be set too large. Therefore, as described above, the minimum width H1 of the first magnetic bridge B1 is defined based on the first long side LS1, which has a greater influence on the change in mass. However, the length of the first short side SS1 (first width) can also be considered, and the minimum width H1 of the first magnetic bridge B1 can be defined by the area.

[0091] Specifically, the length per unit area L12 (not shown) [= minimum width H1 (mm) / cross-sectional area S1 (mm2)] obtained by dividing the minimum width H1 of the first magnetic bridge B1 by the cross-sectional area S1 (not shown) of the first adhesive magnet MG1 is preferably 1.5% / mm or more and 2.5% / mm or less.

[0092] That is, preferably 1.5% / mm≤L12×100 (% / mm)≤2.5% / mm, so that the leakage flux of the first adhesive magnet MG1 can be suppressed to a small extent, and sufficient strength of the first magnetic bridge B1 can be ensured.

[0093] Furthermore, if the cross-section of the first adhesive magnet MG1 is a roughly quadrilateral cross-section after the corners are beveled, or a roughly quadrilateral cross-section like a trapezoid, as long as its cross-sectional area is also controlled within the aforementioned range as the cross-sectional area S1, the leakage flux of the first adhesive magnet MG1 can be suppressed to a small extent, and sufficient strength of the first magnetic bridge B1 can be ensured.

[0094] "Second magnetic bridge B2"

[0095] like Figure 3 As shown, the second gap portion 42B, which is symmetrically arranged on one side of the d-axis, has an extended wall portion 42B1 that extends in a curved shape toward the d-axis side, and the second magnetic bridge B2 has a minimum width H2.

[0096] Furthermore, the minimum width H2 of the second magnetic bridge B2 is less than 30% of the length L21 (not shown) of the second long side LS2 [(H2 (mm) / L21 (mm))×100 (%)≤30 (%)], specifically, the minimum width H2 of the second magnetic bridge B2 is 2.6 mm (approximately 22.6% of the length of the second long side LS2).

[0097] Furthermore, the minimum width H2 of the second magnetic bridge B2 is greater than the minimum width H1 of the first magnetic bridge B1 because there is a tendency to apply greater stress to the second magnetic bridge B2 than to the first magnetic bridge B1.

[0098] The minimum width H2 can be set to such a small size because the density of the second adhesive magnet MG2 is low, which reduces the mass of the second adhesive magnet MG2 that affects stress.

[0099] In addition, the protruding wall portion 42B1 has an arc-shaped wall portion CA that extends radially inward from a position P that is closer to the minimum width H2 of the second magnetic bridge B2 with a predetermined radius of curvature, and extends radially outward from the d-axis end portion 42A1 of the second configuration hole portion 42A.

[0100] Thus, by placing the position P of the minimum width H2 of the second magnetic bridge B2 on the arc-shaped wall CA that disperses stress, damage to the second magnetic bridge B2 can be further avoided.

[0101] Specifically, if the specified radius of curvature of the arc-shaped wall CA is set to be above 3mm and below 10mm, it can avoid the stress concentration point caused by the radius of curvature being too small, and it can also prevent the stress dispersion effect from being reduced by the radius of curvature being too large and making it close to a straight shape.

[0102] Moreover, although the second magnetic bridge B2 becomes the magnetic circuit for the leakage flux of the second adhesive magnet MG2, the ease of flux flow depends on the minimum width H2 of the second magnetic bridge B2.

[0103] Therefore, compared to conventional structures, the rotor 20 of this embodiment, which can make the minimum width H2 of the second magnetic bridge B2 smaller, can suppress the leakage flux of the second adhesive magnet MG2 to a lower level.

[0104] On the other hand, it is preferable that the minimum width H2 of the second magnetic bridge B2 is more than 20% of the length L21 (not shown) of the second long side LS2 [(H2 (mm) / L21 (mm))×100 (%)≥20 (%)], so as to ensure sufficient strength of the second magnetic bridge B2 and further avoid damage to the second magnetic bridge B2.

[0105] Furthermore, due to the size of the second adhesive magnet MG2 installed on the rotor 20, the width of the second short side SS2 (i.e., the second width in the direction orthogonal to the second long side LS2) cannot be set too large. Therefore, as described above, the minimum width H2 of the second magnetic bridge B2 is defined based on the second long side LS2, which has a greater impact on the change in mass. However, the length of the second short side SS2 (second width) can also be considered, and the minimum width H2 of the second magnetic bridge B2 can be defined by the area.

[0106] Specifically, the length per unit area L22 (not shown) [= minimum width H2 (mm) / cross-sectional area S2 (mm2)] obtained by dividing the minimum width H2 of the second magnetic bridge B2 by the cross-sectional area S2 (not shown) of the second adhesive magnet MG2 is preferably 5.0% / mm or more and 7.5% / mm or less.

[0107] That is, preferably 5.0% / mm≤L22×100 (% / mm)≤7.5% / mm, so that the leakage flux of the second adhesive magnet MG2 can be suppressed to a small extent and sufficient strength of the second magnetic bridge B2 can be ensured.

[0108] Furthermore, if the cross-section of the second adhesive magnet MG2 is a roughly quadrilateral cross-section with chamfered corners or a roughly quadrilateral cross-section like a trapezoid, as long as its cross-sectional area is also controlled within the aforementioned range as the cross-sectional area S2, the leakage flux of the second adhesive magnet MG2 can be suppressed to be small, and sufficient strength of the second magnetic bridge B2 can be ensured.

[0109] In addition, the minimum width H2 of the second magnetic bridge B2 is preferably 2.4 mm or more and 2.9 mm or less, which can suppress leakage flux to a low level and ensure sufficient strength of the second magnetic bridge B2.

[0110] On the other hand, the second gap portion 42B, which is symmetrically arranged on one side sandwiching the d-axis, includes: an extension wall portion 42B2 that extends from the second configuration hole portion 42A in a direction that causes the second short side SS2 (also called the second side side) of the second adhesive magnet MG2 on the d-axis side to extend radially outward, and an R wall portion 42B3 that connects the front ends of the arc-shaped wall portion CA and the radially outward side of the extension wall portion 42B2.

[0111] In addition, the R-wall portion 42B3 is also a component that connects the front ends of the protruding wall portion 42B1 and the extended wall portion 42B2 to the radially outer side.

[0112] In this way, the second gap 42B on one side extends radially outward in such a way that it cuts off the magnetic circuit of the leakage flux around the second short side SS2 (second side) on the d-axis side of the second adhesive magnet MG2, so that the leakage flux can be further reduced.

[0113] In addition, the protruding wall portion 42B1 has an inner arc-shaped wall portion ICA that extends radially inward from the arc-shaped wall portion CA with a radius of curvature smaller than that of the arc-shaped wall portion CA toward the radially inward of the second configuration hole portion 42A. This will not cause stress concentration, and will ensure a width that is wider than the minimum width H2 of the second magnetic bridge B2, and will easily prevent damage to the second magnetic bridge B2.

[0114] Furthermore, the second gap portion 42B, which is symmetrically arranged on one side sandwiching the d-axis, also includes a limiting wall portion 42B4, which is provided between the inner arc-shaped wall portion ICA and the second placement hole portion 42A and extends radially outward to restrict the movement of the second adhesive magnet MG2 toward the d-axis side.

[0115] The limiting wall portion 42B4 may also be a component provided adjacent to the radially inner end of the protruding wall portion 42B1.

[0116] According to the above-described embodiment, using low-density adhesive magnets (first adhesive magnet MG1 and second adhesive magnet MG2) for the magnets forming the magnetic poles, it is possible to obtain mechanical strength that avoids damage to the first magnetic bridge B1 and the second magnetic bridge B2. Furthermore, the minimum width H1 of the first magnetic bridge B1 can be narrowed to less than 10% of the length of the first long side LS1 of the first adhesive magnet MG1, and the minimum width H2 of the second magnetic bridge B2 can be narrowed to less than 30% of the length of the second long side LS2 of the second adhesive magnet MG2 on the d-axis side. Therefore, the leakage flux of the first adhesive magnet MG1 and the second adhesive magnet MG2 can be reduced.

[0117] Although the above description is based on specific embodiments, the present invention is not limited to the above embodiments. Changes and improvements to the embodiments are also included within the technical scope of the present invention, which is obvious to those skilled in the art based on the description of the technical solution.

[0118] In addition, the following notes are disclosed regarding the aforementioned first embodiment.

[0119] [Appendix 1]

[0120] A rotor, a rotor for a motor, comprises: a plurality of first adhesive magnets arranged in units of magnetic poles; a plurality of second adhesive magnets arranged in units of magnetic poles; and a rotor core housing the first and second adhesive magnets. The first adhesive magnets have a generally quadrilateral cross-section having a first long side and a first width in a direction orthogonal to the first long side. The second adhesive magnets have a generally quadrilateral cross-section having a second long side and a second width in a direction orthogonal to the second long side. The rotor core comprises: a pair of first holes symmetrically arranged to sandwich a first magnetic bridge located on a radially outer d-axis, and housing the first adhesive magnets; and a pair of second... The first hole portion is symmetrically arranged with a second magnetic bridge located on the radially inner d-axis sandwiched between it, and each hole portion accommodates a plurality of the second adhesive magnets. The first hole portion includes: a first placement hole portion for placing the first adhesive magnet; and a first gap portion on one side disposed between the first placement hole portion and the first magnetic bridge. The second hole portion includes: a second placement hole portion for placing the second adhesive magnet; and a second gap portion on one side disposed between the second placement hole portion and the second magnetic bridge. The minimum width of the first magnetic bridge is 10% or less of the length of the first long side, and the minimum width of the second magnetic bridge is 30% or less of the length of the second long side of the second adhesive magnet on the d-axis side.

[0121] [Note 2] According to the rotor described in Note 1, the minimum width of the first magnetic bridge is 6% or more of the length of the first long side, and the minimum width of the second magnetic bridge is 20% or more of the length of the second long side of the second adhesive magnet on the d-axis side.

[0122] [Appendix 3] According to the rotor described in Appendix 1 or 2, the second gap portion includes: a protruding wall portion that extends in a curved manner toward the d-axis side; and an extension wall portion that extends from the aforementioned second arrangement hole portion in a direction that extends the second side edge of the second adhesive magnet on the d-axis side toward the radially outward direction. The protruding wall portion includes: an arcuate wall portion that extends radially inward from a position greater than the minimum width of the second magnetic bridge and toward the radially outward from the d-axis side end of the second arrangement hole portion with a predetermined radius of curvature. The second gap portion includes: an R-wall portion that connects the radially outward front ends of the arcuate wall portion and the extension wall portion.

[0123] [Note 4] The rotor according to Note 3, wherein the specified radius of curvature is 3 mm or more and 10 mm or less.

[0124] [Note 5] The rotor according to any one of Notes 1 to 4, wherein the minimum width of the second magnetic bridge is 2.4 mm or more and 2.9 mm or less.

[0125] [Note 6] The rotor according to any one of Notes 1 to 5, wherein the density of the first adhesive magnet and the second adhesive magnet is 6.5 g / cm3 or less.

[0126] [Appendix 7] The rotor according to any one of Appendices 1 to 6, wherein the length per unit area obtained by dividing the minimum width of the second magnetic bridge by the cross-sectional area of ​​the second adhesive magnet on the d-axis side is 5.0% / mm or more and 7.5% / mm or less.

[0127] [Appendix 8] The rotor according to any one of Appendices 1 to 7, wherein the length per unit area obtained by dividing the minimum width of the first magnetic bridge by the cross-sectional area of ​​the first adhesive magnet is 1.5% / mm or more and 2.5% / mm or less.

Claims

1. A type of rotor, specifically the rotor of a motor. The rotor described above is characterized by having: Multiple first adhesive magnets are arranged in units of magnetic poles; Multiple second adhesive magnets, arranged in units of magnetic poles; and The rotor core houses the first adhesive magnet and the second adhesive magnet mentioned above. The aforementioned first adhesive magnet has a cross-section with a generally quadrilateral shape, having a first long side and a first width in a direction orthogonal to the first long side. The second adhesive magnet described above has a cross-section with a generally quadrilateral shape, having a second long side and a second width in a direction orthogonal to the second long side. The aforementioned rotor core has the following features: A pair of first openings, symmetrically arranged to sandwich a first magnetic bridge located on the radially outer d-axis, and housing the aforementioned first adhesive magnet; and A pair of second holes are symmetrically arranged, sandwiching the second magnetic bridge located on the aforementioned d-axis on the radially inner side, and each hole houses a plurality of the aforementioned second adhesive magnets. The aforementioned first hole has: A first mounting hole is provided, wherein the aforementioned first adhesive magnet is mounted; and A first gap on one side is disposed between the first configuration hole and the first magnetic bridge. The aforementioned second hole has: The second configuration hole is configured with the aforementioned second adhesive magnet; and A second gap on one side is disposed between the second configuration hole and the second magnetic bridge. The minimum width of the first magnetic bridge is less than 10% of the length of the first long side. The minimum width of the second magnetic bridge is less than 30% of the length of the second long side of the second adhesive magnet on the d-axis side.

2. The rotor according to claim 1, characterized in that, The minimum width of the first magnetic bridge is at least 6% of the length of the first long side. The minimum width of the second magnetic bridge is more than 20% of the length of the second long side of the second adhesive magnet on the d-axis side.

3. The rotor according to claim 1 or 2, characterized in that, The aforementioned second gap includes: The protruding wall portion extends in a curved shape toward the aforementioned d-axis side; and The extended wall portion extends from the aforementioned second arrangement hole portion in a direction that causes the second side edge of the second adhesive magnet on the d-axis side to extend radially outward. The aforementioned protruding wall portion includes an arc-shaped wall portion extending radially inward from a position greater than the minimum width of the second magnetic bridge, with a predetermined radius of curvature, and extending radially outward from the d-axis end portion of the second configuration hole portion. The second gap includes an R-shaped wall portion that connects the front end portion of the arc-shaped wall portion and the radially outer side of the extended wall portion.

4. The rotor according to claim 3, characterized in that, The specified radius of curvature is 3mm or more and 10mm or less.

5. The rotor according to claim 1 or 2, characterized in that, The minimum width of the second magnetic bridge B2 is 2.4 mm or more and 2.9 mm or less.

6. The rotor according to claim 1 or 2, characterized in that, The density of the first and second adhesive magnets mentioned above is 6.5 g / cm³. 3 the following.

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