Rotor core, rotor, and rotating electrical machine

Abstract

Provided is a rotor core (10) comprising: a plurality of annular electromagnetic steel plates (11) having reduced-thickness portions (200) where the plate thickness is reduced; and magnet holes for installing a plurality of magnets constituting a plurality of magnetic poles (100). The rotor core (10) is characterized in that: the plurality of magnetic poles (100) each include a first magnet hole (110) for installing a first magnet (101) disposed at the center of each magnetic pole (100) in the circumferential direction of the electromagnetic steel plates (11), a second magnet hole (120) for installing a second magnet (102) disposed on the front Rf side in the rotational direction with respect to the first magnet (101), and a third magnet hole (130) for installing a third magnet (103) disposed on the rear Rr side in the rotational direction with respect to the first magnet (101); and the reduced-thickness portion (200) includes a first reduced-thickness portion (210) provided in at least a part between the first magnet hole (110) and the second magnet hole (120).

Description

Rotor core, rotor and rotating electric machine

[0001] This application claims priority to Japanese Patent Application No. 2024-129838, filed on August 6, 2024, the contents of which are incorporated herein by reference.

[0002] As the electrification of automobiles progresses, there is a demand for compact, high-output motors for electric vehicles. At the same time, there has been an increasing demand for improved ride comfort in electric vehicles in recent years. Motor vibration is an important factor in the ride comfort of electric vehicles, and suppressing motor vibration has become an important issue.

[0003] For example, in Patent Document 1, a recess is provided in the outer diameter shape of a rotor core used in a motor to alleviate magnetic flux changes and thereby reduce noise. Also, in Patent Document 2, a magnetic steel sheet is partially etched to reduce or remove the sheet thickness, thereby reducing magnetic short circuits.

[0004] JP 2013-27150 A JP 2011-114927 A

[0005] The inventors discovered that motor vibration is affected by fluctuations in electromagnetic force generated in the direction of rotation of the rotor core between the stator core and rotor core that make up the motor, and attempted to reduce the fluctuations in electromagnetic force in the direction of rotation of the rotor core by changing the motor core shape, etc. The present invention was made in light of the above, and an object of the present invention is to provide a rotor core that can suppress fluctuations in electromagnetic force in the direction of rotation of the rotor core and thereby suppress vibration during rotation.

[0006] (1) A rotor core according to one aspect of the present invention is a rotor core comprising: a plurality of annular electromagnetic steel plates having a reduced thickness portion; and magnet holes for installing a plurality of magnets constituting a plurality of magnetic poles, wherein each of the plurality of magnetic poles includes: a first magnet hole for installing a first magnet that is positioned at the center of the magnetic pole in the circumferential direction of the electromagnetic steel plates; a second magnet hole for installing a second magnet that is positioned forward in the direction of rotation relative to the first magnet; and a third magnet hole for installing a third magnet that is positioned rearward in the direction of rotation relative to the first magnet, wherein the reduced thickness portion includes a first reduced thickness portion provided in at least a portion between the first magnet hole and the second magnet hole.

[0007] (2) In the rotor core described in (1) above, the first reduced-wall portion may have a connecting portion connecting the first magnet hole and the second magnet hole. (3) In the rotor core described in (2) above, the first reduced-wall portion may further include an outer portion connecting the outer periphery of the electromagnetic steel sheet and at least a portion of a radially outer portion of the connecting portion. (4) In the rotor core described in (3) above, the outer portion may be provided over the entire area between the outer periphery of the electromagnetic steel sheet and the connecting portion. (5) In the rotor core described in any one of (2) to (4) above, the first reduced-wall portion may further include an inner portion connected to at least a portion of a radially inner portion of the connecting portion. (6) In the rotor core described in any one of (1) to (5) above, the reduced-wall portion may further include a second reduced-wall portion provided in at least a portion between adjacent magnetic poles. (7) In the rotor core described in (6) above, the second thin-wall portion may have a connecting portion connecting adjacent magnetic poles. (8) In the rotor core described in (7) above, the second thin-wall portion may further include an outer portion connecting the outer circumferential edge of the electromagnetic steel sheet and at least a portion of a radially outer portion of the connecting portion of the second thin-wall portion. (9) In the rotor core described in (8) above, the outer portion of the second thin-wall portion may be provided entirely between the outer circumferential edge of the electromagnetic steel sheet and the connecting portion. (10) In the rotor core described in any one of (7) to (9) above, the second thin-wall portion may further include an inner portion connected to at least a portion of a radially inner portion of the connecting portion of the second thin-wall portion. (11) In the rotor core described in any one of (1) to (10) above, the thin-wall portion may further include a third thin-wall portion provided in at least a portion between the first magnet hole and the third magnet hole.

[0008] (12) A rotor according to one aspect of the present invention is characterized by comprising: a rotor core according to any one of (1) to (11) above; the first magnets installed in the first magnet holes of the rotor core; the second magnets installed in the second magnet holes of the rotor core; the third magnets installed in the third magnet holes of the rotor core; and a rotating shaft provided at the center of the rotor core. (13) A rotating electric machine according to one aspect of the present invention is characterized by comprising: the rotor according to (12) above; and a stator.

[0009] According to the rotor core of the present invention, fluctuations in electromagnetic force in the rotation direction of the rotor core are suppressed, and vibrations during rotation can be suppressed.

[0010] FIG. 1 is a schematic cross-sectional view of a rotating electric machine according to an embodiment of the present invention; FIG. 2 is a view for explaining a first thinning portion according to an embodiment of the present invention, and corresponds to the partially enlarged view of FIG. 1; FIG. 3 is a view for explaining a first thinning portion according to another embodiment of the present invention; FIG. 4 is a view for explaining a first thinning portion according to another embodiment of the present invention; FIG. 5 is a view for explaining a second thinning portion according to an embodiment of the present invention, and corresponds to the partially enlarged view of FIG. 1; FIG. 6 is a view for explaining a second thinning portion according to another embodiment of the present invention; FIG. 7 is a view for explaining a third thinning portion according to an embodiment of the present invention, and corresponds to the partially enlarged view of FIG. 1;

[0011] Hereinafter, embodiments of the present invention will be described using examples, but it is obvious that the present invention is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be exemplified, but other numerical values ​​and materials may be applied as long as the effects of the present invention are obtained. Furthermore, the components of the following embodiments can be combined with each other.

[0012] (Rotating Electric Machine) FIG. 1 shows a schematic cross-sectional view of a rotating electric machine 1000 according to this embodiment. The rotating electric machine 1000 is a motor or a generator. The motor may be a vehicle motor or may be used for other purposes. The motor is not particularly limited, and the motor type may be, for example, an IPM (Interior Permanent Magnet) motor or an EESM (Electrically Excited Synchronous Motor). The rotating electric machine may also be an outer rotor motor. The rotating electric machine 1000 according to this embodiment includes a rotor 1 and a stator 3. Note that FIG. 1 shows only the necessary components for explanation, and therefore omits other components included in the rotating electric machine 1000. Furthermore, coils and the like included in the stator 3 are also omitted. Figure 1 is a cross-sectional view of the rotor 1 and stator 3 of the rotating electric machine 1000 viewed from the stacking direction, and corresponds to a view of the rotating electric machine 1000 cut along a direction (radial direction) perpendicular to the center line O between adjacent electromagnetic steel plates 11 in the stacking direction.

[0013] 1, the stator 3 includes an annular core back 31 and a plurality of teeth 32 that are spaced apart in the circumferential direction and protrude radially from the core back 31 toward the center (center line O) of the stator 3. In the rotating electric machine 1000, the rotor 1 and the stator 3 are arranged so as to share the same center line O.

[0014] (Rotor) As shown in Fig. 1 , the rotor 1 includes a rotor core 10 and a rotating shaft 2 provided at the center of the rotor core 10. When configured as the rotor 1, the rotor core 10 rotates around a center line O of the rotor 1 as the rotation axis of the rotating shaft 2. In this embodiment, the rotation direction of the rotor 1 is counterclockwise on the page of Fig. 1 etc. The center line O of the rotor 1 and the center line O of the rotor core 10 coincide with each other. The rotor core 10 is configured by laminating a plurality of annular electromagnetic steel plates 11 with the center line O as the center (center of gravity) of the rotor core 10.

[0015] Hereinafter, the direction perpendicular to the center line O is referred to as the radial direction, and the direction going around the center line O is referred to as the circumferential direction. The direction in which the electromagnetic steel sheets 11 are stacked is the direction in which the center line O extends (plate thickness direction), and is referred to as the stacking direction. In the example of FIG. 1 , the rotor 1 rotates counterclockwise in the rotation direction (hereinafter simply referred to as the rotation direction). However, although the rotor 1 may also rotate in the reverse clockwise direction, the counterclockwise direction is still referred to as the rotation direction even when rotating in the reverse direction. For example, if the rotating electric machine 1000 is a drive motor for a vehicle, the forward direction is the rotation direction, and the reverse direction is the reverse rotation.

[0016] (Electromagnetic Steel Sheets) As shown in Fig. 1 , each of the electromagnetic steel sheets 11 that make up the rotor core 10 has an overall ring-shaped (annular) outer shape when viewed in the stacking direction. The outer shapes of the electromagnetic steel sheets 11 form the outer shape of the rotor core 10 when viewed in the stacking direction. In other words, the radially outermost edge (outer peripheral edge 11e) of the annular electromagnetic steel sheets 11 forms the outer peripheral edge of the rotor core 10. When a rotor 1 constructed using this rotor core 10 is configured as a rotating electric machine 1000, for example, as shown in Fig. 1 , the rotor 1 is disposed radially inside the stator 3, and the outer peripheral edge 11e faces the inner peripheral edge of the annular stator 3.

[0017] The electromagnetic steel sheets 11 also have multiple gaps for installing magnets. When multiple electromagnetic steel sheets 11 are stacked, the gaps in each electromagnetic steel sheet 11 are connected in the stacking direction, thereby forming three magnet holes, the first magnet hole 110, the second magnet hole 120, and the third magnet hole 130, arranged in a ∇ (nabla) shape for each magnetic pole 100 (the area indicated by the dashed dotted line), as shown in FIG. 1 . The first magnet hole 110 is formed on the radially outer side, with its longitudinal direction extending generally along the circumferential direction. The second magnet hole 120 is located on the forward Rf side of the first magnet hole 110 in the rotational direction (counterclockwise in the circumferential direction in the example of FIG. 1 ), and its longitudinal direction extends generally along the radial direction. The third magnet hole 130 is located on the rear Rr side of the first magnet hole 110 in the rotational direction (clockwise in the circumferential direction in the example of FIG. 1 ), and its longitudinal direction extends generally along the radial direction. 1 to 8 are merely examples. The shape of the magnetic pole 100 is affected by the size and magnetic force of the magnet, and is therefore not limited to the shapes shown in FIGS. 1 to 8.

[0018] In the assembled state of rotor 1 ( FIG. 1 ), three magnets (first magnet 101, second magnet 102, and third magnet 103) are provided in these three magnet holes. Each magnet is installed in the magnet hole so as to penetrate laminated electromagnetic steel sheets 11 in the lamination direction. Each magnet is also fixed to electromagnetic steel sheets 11 that constitute rotor core 10 by adhesive or the like.

[0019] Note that when each magnet is installed in its corresponding magnet hole, there may be a space between the magnet and the magnet hole (the gap in the electromagnetic steel sheet 11). In the embodiment shown in FIG. 1 , as shown, each magnet hole has a longitudinal shape (rectangular) when viewed from the stacking direction, and has a longitudinal length such that a space is formed at both ends of the magnet in the longitudinal direction when the magnet is installed. Such a space provided on the longitudinal end side of the magnet may be integrally formed so as to be connected to the magnet installation space as shown in FIG. 1 , or may have at least a portion provided so as to be separated from the magnet via a steel plate portion. Such a space on the longitudinal end side of the magnet is also called a flux barrier and may be provided to control the flow of magnetic flux during operation of the rotating electric machine 1000. However, the shape of this space when viewed from the stacking direction can take various shapes and is therefore arbitrary. Hereinafter, the term "magnet hole" will be understood to include the space formed on the longitudinal end side of the magnet as described above. This space may be filled with a tangible object or may simply be empty space. Each magnet may be made up of multiple magnets, in which case each magnet hole may also be made up of multiple holes. Also, although there are eight magnetic poles in the rotor 1 in the embodiment shown in Figure 1, the number may be any number (even number).

[0020] (Thinned Portion of Electromagnetic Steel Sheet 11) Here, each of the electromagnetic steel sheets 11 constituting the rotor core 10 has a thinned portion 200 where the sheet thickness has been reduced. That is, the thickness of the thinned portion 200 (sheet thickness) is thinner than the area of ​​the electromagnetic steel sheet 11 other than the thinned portion 200. For example, the thinned portion 200 may be formed by pressing or etching the electromagnetic steel sheet 11. These methods make it possible to form the thinned portion 200 in the electromagnetic steel sheet 11 without affecting the external shape of the rotor core 10. The thinned portion 200 may be appropriately set within a range that can obstruct the flow of magnetic flux, but excessive thinning significantly reduces strength. For this reason, the thinned portion 200 may have a thickness that is 25 to 50% or less of the sheet thickness of the electromagnetic steel sheet 11, for example. The thinned portions 200 may be in a range of thicknesses that are 25 to 40% or less of the thickness of the electromagnetic steel sheet 11, or in a range of thicknesses that are 25 to 35% or less of the thickness of the electromagnetic steel sheet 11. The thicknesses of the thinned portions 200 may be the same or different when compared to each other. Furthermore, the thickness of the thinned portions 200 may be constant or variable within the range of a single thinned portion 200. By providing flux barriers at both ends of the magnet, separated from the magnet holes, it is possible to control the flow of magnetic flux in the same way as by providing the thinned portions 200. However, providing a flux barrier results in a region where the width of the electromagnetic steel sheet 11 is narrowed (i.e., a bridge portion), which may reduce the mechanical strength against the centrifugal force generated during rotor rotation. It has been confirmed that providing the thinned portions 200 as in this embodiment reduces the thickness of the electromagnetic steel sheet 11 but barely changes its mechanical strength, and therefore higher strength can be expected compared to providing a flux barrier. However, if there is a margin for mechanical strength, a design may be adopted that aims to control the flow of magnetic flux by providing both a flux barrier and a thinned portion 200 .

[0021] The inventors discovered that providing a reduced-metal portion 200 within the magnetic pole formed by the magnets arranged in a V-shape suppresses fluctuations in electromagnetic force and vibration during rotation. They found that providing the first reduced-metal portion 210 between the first magnet hole 110 and the second magnet hole 120 is particularly effective. While FIG. 1 illustrates an example of areas where the first reduced-metal portion 210, second reduced-metal portion 220, and third reduced-metal portion 230 may be provided, it is sufficient that at least the first reduced-metal portion 210 is present. Furthermore, the shape of the reduced-metal portion 200 is not limited to the example shown in FIG. 1 .

[0022] The reduced-metal portion 200 will be described in detail below with reference to Figures 2 to 8. Figures 2 to 8 are each a schematic cross-sectional view showing a portion of a rotor according to an embodiment.

[0023] First, the three magnet holes and three magnets of the rotor 1 will be described in detail using Figure 2. Figure 2 shows a portion of the rotor 1 in which only the first thinned portion 210 is provided. As shown in Figure 2, the first magnet hole 110 is a magnet hole for installing the first magnet 101, which is located at the center of the magnetic pole 100 in the circumferential direction of the electromagnetic steel sheet 11. The second magnet hole 120 is a magnet hole for installing the second magnet 102, which is located on the forward Rf side of the first magnet 101 in the direction of rotation. The third magnet hole 130 is a magnet hole for installing the third magnet 103, which is located on the rear Rr side of the first magnet 101 in the direction of rotation.

[0024] The first magnet hole 110, the second magnet hole 120, and the third magnet hole 130 each have a radially inner edge (110a, 120a, 130a), a radially outer edge (110b, 120b, 130b), a rotational leading edge (110c, 120c, 130c), and a rotational trailing edge (110d, 120d, 130d). In the example of FIG. 2, the radially inner edge 110a and the radially outer edge 110b of the first magnet hole 110 extend in a direction intersecting the radial direction. When viewed from the stacking direction, the radially inner edge 110a and the radially outer edge 110b may be perpendicular to the radial direction or may be inclined relative to a direction perpendicular to the radial direction. For the first magnet hole 110, the radially inner edge 110a and the radially outer edge 110b are longer than the rotational leading edge 110c and the rotational trailing edge 110d. For the second magnet hole 120 and the third magnet hole 130, the rotational leading edges (120c, 130c) and rotational trailing edges (120d, 130d) are longer than the radially inner edges (120a, 130a) and radially outer edges (120b, 130b). The radially outer edge (120b) of the second magnet hole 120 is located forward in the direction of rotation Rf than the radially inner edge (120a). The radially outer edge (130b) of the third magnet hole 130 is located rearward in the direction of rotation Rr than the radially inner edge (130a). The rotational leading edges (120c, 130c) and rotational trailing edges (120d, 130d) extend at an angle relative to the radial direction, but this is not limited to this. For example, the rotating front edges (120c, 130c) and the rotating rear edges (120d, 130d) may be parallel to the radial direction when viewed from the stacking direction.

[0025] The first magnet 101, the second magnet 102, and the third magnet 103 are each magnets having a long surface when viewed in the stacking direction. When viewed in the stacking direction, the first magnet 101 is arranged so that a pair of long sides faces the radially inner edge 110a and the radially outer edge 110b of the corresponding magnet hole. When viewed in the stacking direction, the first magnet 101 is arranged so that a pair of short sides faces the rotational front edge 110c and the rotational rear edge 110d of the corresponding magnet hole. When viewed in the stacking direction, the second magnet 102 and the third magnet 103 are arranged so that a pair of short sides faces the radially inner edge (120a, 130a) and the radially outer edge (120b, 130b) of the corresponding magnet hole. When viewed from the stacking direction, the second magnet 102 and the third magnet 103 are arranged such that their respective pairs of long sides face the rotational front edge (120c, 130c) and rotational rear edge (120d, 130d) of the corresponding magnet holes. For example, the direction perpendicular to the long sides of each magnet (the magnet's magnetization direction) may be aligned with or tilted from the radial direction.

[0026] The magnets are arranged such that the second magnet hole 120 is arranged on the forward Rf side in the rotational direction from the circumferential center of the first magnet hole 110, and the third magnet hole 130 is arranged on the rear Rr side in the rotational direction from the circumferential center of the first magnet hole 110. That is, the second magnet 102 is arranged on the forward Rf side in the rotational direction relative to the first magnet 101, and the third magnet is arranged on the rear Rr side in the rotational direction relative to the first magnet.

[0027] In such a V-shaped magnet arrangement, the thinning portion 200 has at least one thinning portion selected from a first thinning portion 210, a second thinning portion 220, and a third thinning portion 230. The first thinning portion 210 is provided at least partially between the first magnet hole 110 and the second magnet hole 120. The second thinning portion 220 is provided at least partially between adjacent magnetic poles 100. The third thinning portion 230 is provided at least partially between the first magnet hole 110 and the third magnet hole 130.

[0028] In this way, by including at least one of first thinning portion 210, second thinning portion 220, and third thinning portion 230 in thinning portion 200 as described below, the flow of magnetic flux passing through the thinning portion is hindered more than when no thinning portion is provided. In particular, as described below, by arranging thinning portion 200 in a specific position relative to the arrangement of the magnets in electromagnetic steel sheet 11, it is possible to control the magnetic field generated in electromagnetic steel sheet 11. By utilizing this effect and appropriately designing the magnetic circuit of rotor core 10 made of electromagnetic steel sheet 11, it is possible to suppress fluctuations in electromagnetic force in the rotational direction of rotor core 10 and suppress vibration during rotation. Numerical analysis was performed on the case where the thinned portion 200 includes the first thinned portion 210, the second thinned portion 220, and the third thinned portion 230, and it was confirmed that the first thinned portion 210 makes the greatest contribution to suppressing fluctuations in electromagnetic force, and that there is no significant difference in the contributions of the second thinned portion 220 and the third thinned portion 230 to suppressing fluctuations in electromagnetic force. Furthermore, by including at least one of the first thinned portion 210, the second thinned portion 220, and the third thinned portion 230 in the thinned portion 200, as described below, the magnetic field generated in the electromagnetic steel sheet 11 can be controlled, and the strength required of the electromagnetic steel sheet 11 can be balanced. Below, each thinned portion (210 to 230) will be described in order, starting with the first thinned portion 210.

[0029] (First Thinned Portion) The first thinned portion 210 will be described using FIGS. 2 to 5. As shown in FIGS. 2 to 5, the first thinned portion 210 is provided on the outer peripheral edge 11e side of the electromagnetic steel sheet 11, at least partially between the first magnet hole 110 and the second magnet hole 120. By providing the first thinned portion 210, the flow of magnetic flux passing through the first thinned portion 210 is impeded compared to when the first thinned portion 210 is not provided. By utilizing this effect and appropriately designing the magnetic circuit, fluctuations in electromagnetic force in the rotational direction of the rotor core 10 can be suppressed, thereby suppressing vibration during rotation. Note that the shape of the first thinned portion 210 is not limited to the shape shown in FIG. 2. As described below, if the first thinned portion 210 is formed to have a portion connecting the first magnet hole 110 and the second magnet hole 120 along the circumferential direction, the first thinned portion 210 may have a greater radial width.

[0030] The outer peripheral edge 11e side of the electromagnetic steel sheet 11 here means the radially outer range relative to the radially innermost position of the space (hereinafter referred to as the forward space Sf1; if this space does not exist, the first magnet 101) that exists on the forward Rf side of the rotation direction of the first magnet 101 when the first magnet 101 is installed, when viewed from the stacking direction.

[0031] 2 , the first thinned portion 210 preferably has a portion (connecting portion 201) provided in the electromagnetic steel sheet 11 so as to connect (connect) the first magnet hole 110 and the second magnet hole 120 along the circumferential direction. Specifically, a line L1 is drawn connecting the radially outermost position of the space in the first magnet hole 110, which, when viewed from the stacking direction, exists on the forward Rf side of the first magnet 101 in the direction of rotation when the first magnet 101 is installed, to the radially outermost position of the space (hereinafter referred to as the front space Sf2; if this space does not exist, the second magnet 102) that exists on the forward Rf side of the second magnet 102 in the direction of rotation when the second magnet 102 is installed, and a line L1 is drawn along the circumferential direction from the radially innermost position of the front space Sf1 to the second magnet hole 120, thereby defining the region sandwiched between the first magnet hole 110, the second magnet hole 120, and the two lines L1. In this region, the first thinned portion 210 is preferably provided so as to connect the first magnet hole 110 and the second magnet hole 120. In other words, the first thinned portion 210 is preferably connected to the first magnet hole 110 (forward rotation edge 110c) and the second magnet hole 120 (rear rotation edge 120d) on the outer peripheral edge 11e side of the electromagnetic steel sheet 11, and has a connecting portion 201 provided continuously between the first magnet hole 110 and the second magnet hole 120.

[0032] In this way, by including the connecting portion 201 in the first thinned portion 210, it is possible to control the flow of magnetic flux so as to suppress fluctuations in electromagnetic force. The specific shape of the connecting portion 201 is arbitrary, and it may have a portion that protrudes from the inside of the two lines described above, as shown in FIG. 2. The front space Sf1 may include multiple holes divided by steel plate portions as described above, but at least a portion of the front space Sf1 may be filled with resin or the like. The same applies to the front spaces Sf2 and Sf3 and the rear spaces Sr1, Sr2, and Sr3 described below.

[0033] 3 to 5 and 7 to 8 , in addition to the first thinning portion 210 and the above-described connecting portion 201, the first thinning portion 210 may further include an outer portion 211 or an inner portion 212. Specifically, as shown in FIGS. 3 to 5 , the first thinning portion 210 may further include an outer portion 211 that is provided in at least a portion between the outer peripheral edge 11e of the electromagnetic steel sheet 11 and the connecting portion 201 and connects the outer peripheral edge 11e of the electromagnetic steel sheet 11 and the connecting portion 201. In other words, the outer portion 211 connects the outer peripheral edge 11e of the electromagnetic steel sheet 11 and at least a portion of the radially outer portion of the connecting portion 201 (the portion facing the outer peripheral edge 11e). In this way, when the first thinning portion 210 includes the outer portion 211 in addition to the connecting portion 201, it is possible to more appropriately control the flow of magnetic flux so as to suppress fluctuations in electromagnetic force.

[0034] Fig. 3 shows a portion of the rotor 1 provided with a first thinning portion 210 including an outer portion 211. In the embodiment shown in Fig. 3, the outer portion 211 of the first thinning portion 210 is formed so as to extend over a portion of the outer peripheral edge 11e of the electromagnetic steel sheet 11. In other words, at least a portion of the outer peripheral edge 11e is included in the outer portion 211. In this case, when the electromagnetic steel sheet 11 is viewed from the outside in the radial direction, it can be seen that the thickness of a portion of the outer peripheral edge 11e is reduced in the first thinning portion 210.

[0035] Furthermore, as shown in Fig. 4 , the outer portion 211 may be provided over the entire area between the outer peripheral edge 11e of the electromagnetic steel sheet 11 and the connecting portion 201. Fig. 4 shows a portion of a rotor 1 provided with a first thin-walled portion 210 including an outer portion 211 provided over the entire area between the outer peripheral edge 11e and the connecting portion 201. In the embodiment shown in Fig. 4 , the outer portion 211 may extend in the circumferential direction at least from the first magnet hole 110 to the second magnet hole 120 on the outer peripheral edge 11e side of the electromagnetic steel sheet 11 between the first magnet hole 110 and the second magnet hole 120. This makes it possible to more appropriately control the flow of magnetic flux passing through the first thin-walled portion 210.

[0036] The outer portion 211 being provided throughout the entire area between the outer peripheral edge 11e of the electromagnetic steel plate 11 and the connecting portion 201 means that, when viewed from the stacking direction, the outer portion 211 is arranged in the circumferential direction at least from a straight line extending radially through the intersection of imaginary lines extending from the radial outer edge 110b and the rotational front edge 110c of the first magnet hole 110 to a straight line extending radially through the intersection of imaginary lines extending from the radial outer edge 120b and the rotational rear edge 120d of the second magnet hole 120.

[0037] 4, the outer portion 211 may extend circumferentially rearward in the direction of rotation Rr beyond the intersection of imaginary lines extending from the radially outer edge 110b and the rotational leading edge 110c of the first magnet hole 110. The outer portion 211 may also extend circumferentially forward in the direction of rotation Rf beyond the intersection of imaginary lines extending from the radially outer edge 120b and the rotational trailing edge 120d of the second magnet hole 120.

[0038] As shown in FIG. 5 , the first reduced-material portion 210 may further include an inner portion 212 connected to at least a portion of the radially inner portion (the portion facing the rotating shaft 2) of the connecting portion 201. FIG. 5 shows a portion of the rotor 1 provided with the first reduced-material portion 210 including the outer portion 211 and the inner portion 212. Including the inner portion 212 in addition to the connecting portion 201 in the first reduced-material portion 210 allows for more appropriate control of the flow of magnetic flux so as to suppress fluctuations in electromagnetic force. The inner portion 212 preferably extends radially inward beyond the innermost position of the first magnet hole 110. Note that the embodiment shown in FIG. 5 illustrates an example in which the inner portion 212 is provided throughout the entire radial distance from the innermost portion of the connecting portion 201 to the innermost position of the first magnet hole 110.

[0039] According to the above-described configuration, first thinning portion 210 can suppress fluctuations in electromagnetic force during operation of the rotating electric machine, thereby suppressing vibrations during rotation of rotor core 10. When a numerical analysis was performed on a case where first thinning portion 210 included connecting portion 201, outer portion 211, and inner portion 212 described above, it was confirmed that connecting portion 201 makes the greatest contribution to suppressing fluctuations in electromagnetic force, with connecting portion 201 and outer portion 211 alone contributing approximately 50 to 80%.

[0040] (Second Thinning Portion) Next, the second thinning portion 220 will be described with reference to Figures 6 and 7. Figure 6 shows a portion of the rotor 1 on which, in addition to the first thinning portion 210, a second thinning portion 220 is provided that includes an inner portion 222, which will be described later. Figure 7 shows a portion of the rotor 1 on which, in addition to the first thinning portion 210, a second thinning portion 220 is provided that includes an outer portion 221, which will be described later.

[0041] As shown in FIGS. 6 and 7 , the second thinned portion 220 is provided at least partially between adjacent magnetic poles 100 , for example, on the outer circumferential edge 11 e side of the electromagnetic steel sheet 11 .

[0042] The second thinned portion 220 preferably includes a connecting portion 202 that connects adjacent magnetic poles 100. Furthermore, the second thinned portion 220 may include at least one of an outer portion 221 that connects the outer peripheral edge 11e of the electromagnetic steel sheet 11 to at least a portion of the radially outer side of the connecting portion 202, or an inner portion 222 that is connected to at least a portion of the radially inner side of the connecting portion 202 (the portion facing the rotation shaft 2). Note that, similar to the connecting portion 201 of the first thinned portion 210, the connecting portion 202 preferably connects adjacent magnetic poles 100 on the inside of two lines L2 that are based on the front space Sf2 of the second magnet hole 120 and the rear space Sr3 of the third magnet hole 130 of another adjacent magnetic pole. Specifically, one of the two lines L2 is defined as a line connecting the frontmost position in the rotational direction Rf and the outermost position in the radial direction of the front space Sf2 (or the second magnet 102 if this space is not present) that exists on the front Rf side of the second magnet 102 in the rotational direction when the second magnet 102 is installed, and the rearmost position in the rotational direction Rr and the outermost position in the radial direction of the rear space Sr3 (or the third magnet 103 if this space is not present) that exists on the rear Rr side of the third magnet 103 in the rotational direction when the third magnet 103 is installed. Furthermore, the other of the two lines L2 is defined as a line connecting the frontmost position in the rotational direction Rf and the innermost position in the radial direction of the front space Sf2 (or the second magnet 102 if this space is not present) and the innermost position in the radial direction of the rear space Sr3 (or the third magnet 103 if this space is not present). By having the second thinning portion 220 have the connecting portion 202, the outer portion 221 or the inner portion 222, the same effect as when the above-mentioned first thinning portion 210 includes the connecting portion 201, the outer portion 211 or the inner portion 212 is achieved.

[0043] In the embodiment shown in FIG. 6 , the second thinned portion 220 includes the connecting portion 202 described above. The connecting portion 202 may have a configuration similar to that of the connecting portion 201, except that it is provided to connect adjacent magnetic poles 100. Note that in the example shown in FIG. 6 , the connecting portion 202 extends circumferentially to connect the second magnet hole 120 to the third magnet hole 130 of another magnetic pole adjacent to the second magnet hole 120. Furthermore, in the embodiment shown in FIG. 6 , the second thinned portion 220 includes an inner portion 222 in addition to the connecting portion 202. Preferably, the inner portion 222 extends radially inward from the radially inner line L2 of the two lines L2 described above. The inner portion 222 is connected to at least a portion of the radially inner portion of the connecting portion 202. This configuration allows for more appropriate control of the flow of magnetic flux so as to suppress fluctuations in electromagnetic force.

[0044] In the embodiment shown in FIG. 7 , the second thinning portion 220 further includes an outer portion 221 in addition to the connecting portion 202. In the example of FIG. 7 , the outer portion 221 connects the outer peripheral edge 11e of the electromagnetic steel sheet 11 to the entire radially outer portion of the connecting portion 202, and is provided between the outer peripheral edge 11e and the connecting portion 202. The outer portion 221 is provided at least partially between the outer peripheral edge 11e of the electromagnetic steel sheet 11 and the connecting portion 202, and connects the outer peripheral edge 11e of the electromagnetic steel sheet 11 to the connecting portion 202. The outer portion 221 connects the outer peripheral edge 11e of the electromagnetic steel sheet 11 to at least a portion of the radially outer portion of the connecting portion 202 (the portion facing the outer peripheral edge 11e). In this way, by having the second thinning portion 220 include the outer portion 221 in addition to the connecting portion 202, it is possible to more appropriately control the flow of magnetic flux so as to suppress fluctuations in electromagnetic force.

[0045] The outer portion 221 may extend circumferentially rearward in the direction of rotation Rr beyond the intersection of imaginary lines extending from the radially outer edge 120b and the rotational leading edge 120c of the second magnet hole 120. The outer portion 221 may also extend circumferentially forward in the direction of rotation Rf beyond the radially outer edge 130b and the rotational trailing edge 130d of the third magnet hole 130.

[0046] (Third Thinning Portion) Next, the third thinning portion 230 will be described using Fig. 8. Fig. 8 shows a part of the rotor 1 in which the third thinning portion 230 is provided in addition to the first thinning portion 210. As shown in Fig. 8, the third thinning portion 230 is provided in at least a portion between the first magnet hole 110 and the third magnet hole 130.

[0047] Specifically, as shown in Figure 8, it is preferable that the third thinning portion 230 has a portion (connecting portion 203) provided in the electromagnetic steel plate 11 so as to connect the first magnet hole 110 and the third magnet hole 130 along the circumferential direction. Specifically, a line L3 is drawn connecting the radially outermost position of the rear space Sr1 (which, when viewed from the stacking direction, is the space of the first magnet hole 110 and exists on the rear Rr side of the first magnet hole 110 in the rotational direction when the first magnet 101 is installed) (or the first magnet 101 if this space does not exist). This line L3 connects the radially outermost position of the rear space Sr3 (which would be the third magnet 103 if this space does not exist) that exists on the rear Rr side of the third magnet 103 in the rotational direction when the third magnet 103 is installed. A line L3 is then drawn circumferentially from the radially innermost position of the rear space Sr1 to the third magnet hole 130, thereby defining the region sandwiched between the first magnet hole 110, the third magnet hole 130, and the two lines L3. The third reduced-material portion 230 is preferably provided in this region so as to connect the first magnet hole 110 and the third magnet hole 130. The connecting portion 203 of the third thinned portion 230 may have a configuration similar to that of the connecting portion 201 of the first thinned portion 210 .

[0048] Similarly to the first thin-wall portion 210, the third thin-wall portion 230 includes an outer portion 231 in the embodiment shown in FIG. 8 . Including the outer portion 231 in addition to the connecting portion 203 in this manner allows the flow of magnetic flux to be more appropriately controlled so as to suppress fluctuations in electromagnetic force. In the third thin-wall portion 230, as illustrated in FIG. 8 , the outer portion 231 may be provided over the entire area between the outer peripheral edge 11e of the electromagnetic steel sheet 11 and the connecting portion 203. The outer portion 231 is provided over at least a portion between the outer peripheral edge 11e of the electromagnetic steel sheet 11 and the connecting portion 203, connecting the outer peripheral edge 11e of the electromagnetic steel sheet 11 to the connecting portion 203. The outer portion 231 connects the outer peripheral edge 11e of the electromagnetic steel sheet 11 to at least a portion of the radially outer portion of the connecting portion 203 (the portion facing the outer peripheral edge 11e).

[0049] 8, the outer portion 231 may extend circumferentially forward in the direction of rotation Rf beyond the intersection of imaginary lines extending from the radially outer edge 110b and the rotational rear edge 110d of the first magnet hole 110. The outer portion 231 may extend circumferentially backward in the direction of rotation Rr beyond the intersection of imaginary lines extending from the radially outer edge 130b and the rotational front edge 130c of the third magnet hole 130.

[0050] 8, the third thinned portion 230 includes an inner portion 232 in addition to the connecting portion 203. The inner portion 232 is connected to at least a portion of the radially inner portion of the connecting portion 203. Preferably, the inner portion 232 extends radially inward beyond the innermost position of the first magnet hole 110. This configuration makes it possible to more appropriately control the flow of magnetic flux so as to suppress fluctuations in electromagnetic force.

[0051] The thinned portion 200 may include all of the first thinned portion 210, the second thinned portion 220, and the third thinned portion 230 described above.

[0052] The rotor 1 according to the above embodiment includes the rotor core 10 as described above, and therefore fluctuations in electromagnetic force in the rotation direction of the rotor core 10 are suppressed, and vibrations during rotation can be suppressed.

[0053] The rotor 1 according to the above embodiment can suppress fluctuations in electromagnetic force in the rotation direction of the rotor core 10, thereby suppressing vibrations during rotation. Therefore, when used in a rotating electrical machine, the rotor 1 according to this embodiment can suppress vibrations during rotation while maintaining torque.

[0054] According to the rotor core of the present invention, fluctuations in electromagnetic force in the rotation direction of the rotor core are suppressed, thereby suppressing vibration during rotation. According to the rotor of the present invention, fluctuations in electromagnetic force in the rotation direction of the rotor core are suppressed, thereby suppressing vibration during rotation. Furthermore, according to the rotating electric machine of the present invention, vibration during rotation can be suppressed while maintaining torque. Therefore, the present invention is extremely useful industrially.

[0055] REFERENCE SIGNS LIST 1 rotor 2 rotating shaft 3 stator 10 rotor core 11 electromagnetic steel sheet 11e outer periphery of electromagnetic steel sheet 31 core back 32 teeth 100 magnetic pole 101 first magnet 102 second magnet 103 third magnet 110 first magnet hole 120 second magnet hole 130 third magnet hole 200 reduced-wall thickness portion 210 first reduced-wall thickness portion 211, 221, 231 outer portion 212, 222, 232 inner portion 220 second reduced-wall thickness portion 230 third reduced-wall thickness portion 1000 rotating electric machine Sf1, Sf2, Sf3 front space Sr1, Sr2, Sr3 rear space

Claims

1. A rotor core comprising: a plurality of annular electromagnetic steel plates having thinned portions where the plate thickness has been reduced; and magnet holes for installing a plurality of magnets that constitute a plurality of magnetic poles, wherein each of the plurality of magnetic poles includes: a first magnet hole for installing a first magnet that is positioned at the center of the magnetic pole in the circumferential direction of the electromagnetic steel plates; a second magnet hole for installing a second magnet that is positioned forward in the direction of rotation relative to the first magnet; and a third magnet hole for installing a third magnet that is positioned rearward in the direction of rotation relative to the first magnet; and wherein the thinned portions include a first thinned portion provided in at least a portion between the first magnet hole and the second magnet hole.

2. A rotor core according to claim 1, characterized in that the first thinned portion has a connecting portion that connects the first magnet hole and the second magnet hole.

3. A rotor core according to claim 2, characterized in that the first thinning portion further includes an outer portion connecting the outer peripheral edge of the electromagnetic steel plate and at least a part of the radially outer portion of the connecting portion.

4. A rotor core according to claim 3, characterized in that the outer portion is provided over the entire area between the outer periphery of the electromagnetic steel plate and the connecting portion.

5. A rotor core according to claim 2, characterized in that the first thinning portion further includes an inner portion connected to at least a part of the radially inner portion of the connecting portion.

6. A rotor core according to any one of claims 1 to 5, characterized in that the thinned portion further includes a second thinned portion provided in at least a portion between adjacent magnetic poles.

7. A rotor core according to claim 6, characterized in that the second thinning portion has a connecting portion that connects adjacent magnetic poles.

8. A rotor core according to claim 7, characterized in that the second thinning portion further includes an outer portion connecting the outer peripheral edge of the electromagnetic steel plate and at least a part of the radially outer portion of the connecting portion of the second thinning portion.

9. A rotor core according to claim 8, characterized in that the outer portion of the second thinned portion is provided over the entire area between the outer periphery of the electromagnetic steel plate and the connecting portion.

10. A rotor core according to claim 7, characterized in that the second thinning portion further includes an inner portion connected to at least a part of the radially inner portion of the connecting portion of the second thinning portion.

11. A rotor core according to any one of claims 1 to 5, characterized in that the thinned portion further includes a third thinned portion provided in at least a portion between the first magnet hole and the third magnet hole.

12. A rotor comprising: a rotor core according to any one of claims 1 to 5; the first magnet installed in the first magnet hole of the rotor core; the second magnet installed in the second magnet hole of the rotor core; the third magnet installed in the third magnet hole of the rotor core; and a rotation axis provided at the center of the rotor core.

13. A rotating electric machine comprising the rotor according to claim 12 and a stator.

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