Rotating electric machine

Abstract

A plurality of magnetic pole portions (26) included in a rotor (20) each have a slit (27) formed in a rotor core portion. When the magnetic pole portion is equally divided into twelve regions from one end in the circumferential direction to the other end in the circumferential direction, the fourth to ninth regions of the twelve regions counted in order from one side close to the one end in the circumferential direction are set as a first region (A), a second region (B), a third region (C), a fourth region (D), a fifth region (E), and a sixth region (F), respectively. The plurality of slits includes a first slit (27a) and a second slit (27b). The first slit is arranged in the third area or the sixth area. The second slit is disposed in any one of the first region, the second region, the third region, the fourth region, the fifth region, and the sixth region.

Description

Citation of relevant applications

[0001] This application is based on Japanese Patent Application No. 2022-109159, filed on July 6, 2022, the contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to a rotary electric motor. Background Technology

[0003] In rotating electrical machines, it is well known that there are embedded magnet type rotors, in which permanent magnets are embedded inside the rotor core. In an embedded magnet type rotor, multiple magnetic pole sections, each including a permanent magnet and a portion of the rotor core, are formed circumferentially. This rotor is configured such that, in addition to the magnetic torque generated by the permanent magnets, a reluctance torque is also obtained using a portion of the rotor core. For example, in the embedded magnet type rotor described in Patent Document 1, the magnetic pole sections have slits formed in the rotor core. Through the action of these slits, torque pulsations can be reduced. Existing technical documents Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 10-285845 Summary of the Invention

[0005] In the rotor described above, the configuration of the slits that can more appropriately reduce torque pulses was investigated. The purpose of this invention is to provide a rotary motor capable of reducing torque pulses.

[0006] In a first aspect of this disclosure, a rotary electric motor includes: a rotor having a rotor core and a permanent magnet embedded in the rotor core; and a stator applying a rotating magnetic field to the rotor, and having a plurality of magnetic pole portions, each including the permanent magnet and a portion of the rotor core, formed at equal angular intervals in the circumferential direction on the rotor, each of the plurality of magnetic pole portions having a slit formed in the rotor core, wherein the number of magnetic pole portions is set to P, and the angle from one circumferential end to the other circumferential end of each magnetic pole portion is 360° / P, and the slits formed in the rotor core are arranged such that... When the circumferential end to the other end is divided into twelve regions, the fourth to ninth regions, counted sequentially from the side closest to the circumferential end, are respectively designated as the first region, the second region, the third region, the fourth region, the fifth region, and the sixth region. The plurality of slits includes a first slit and a second slit. The first slit is disposed in the third region or the sixth region, and the second slit is disposed in any one of the first region, the second region, the third region, the fourth region, the fifth region, and the sixth region.

[0007] According to this structure, the width of the phase of the torque pulse when the slit position changes circumferentially is larger in the third and sixth regions than in other regions (see reference). Figure 6 Therefore, among multiple slits, by including a first slit configured in a third or sixth region, the degree of freedom in setting the position of a second slit that generates a torque pulse with the opposite phase relative to the first slit can be increased. Attached Figure Description

[0008] The above-mentioned objects, other objects, features, and advantages of this disclosure will become clearer with reference to the accompanying drawings and the following detailed description. The accompanying drawings are described below. Figure 1 This is a structural diagram of the rotary motor in the implementation method. Figure 2 This is a partial top view showing a portion of the rotor in this configuration. Figure 3 This is a partial top view showing a portion of the rotor in this configuration. Figure 4 This is an explanatory diagram illustrating the position setting of the slit in the rotor in this manner. Figure 5 This is an explanatory diagram illustrating the position setting of the slit in the rotor in this manner. Figure 6 This is a diagram used to illustrate the position setting of the slit in the rotor in this method. Figure 7 This is a diagram used to illustrate the position setting of the slit in the rotor in this method. Figure 8 This is an explanatory diagram illustrating the configuration of the slits in the implementation method and the effective size of each pattern. Figure 9 This is an explanatory diagram illustrating the position setting of the slit in the rotor in this manner. Figure 10 This is an explanatory diagram illustrating the position setting of the slit in the rotor in this manner. Figure 11 This is an explanatory diagram illustrating the position setting of the slit in the rotor in this manner. Figure 12 This is an explanatory diagram used to illustrate the rotor of the modified example. Figure 13 This is a three-dimensional view of the rotor of this modified example. Figure 14 This is an explanatory diagram used to illustrate the rotor of the modified example. Figure 15 This is a three-dimensional view of the rotor of this modified example. Figure 16 This is a three-dimensional view of the rotor of a modified example. Figure 17This is a top view of the rotor in the modified example. Detailed Implementation

[0009] The following describes one embodiment of a rotary electric machine. Figure 1 The rotary motor M shown in this embodiment is a brushless motor of the embedded magnet type. The rotary motor M includes: a generally annular stator 10; and a generally cylindrical rotor 20 rotatably disposed in the radially inner space of the stator 10. The stator 10 applies a rotating magnetic field to the rotor 20.

[0010] (Structure of stator 10) The stator 10 includes a generally annular stator core 11. The stator core 11 is made of a magnetic metal material. The stator core 11 is, for example, constructed by stacking multiple electromagnet steel plates in the direction of axis L1. In this embodiment, the stator core 11 has twelve pole teeth 12 extending radially inward and arranged at equal intervals in the circumferential direction. That is, the stator 10 in this embodiment has twelve slots. Each pole tooth 12 has the same shape as the others. The front end of the pole tooth 12, i.e., the radially inward end, is generally T-shaped, and the front end face 12a is arc-shaped along the outer circumferential surface of the rotor 20.

[0011] A winding 13 is wound on the pole tooth 12, for example, in a concentrated winding manner. The winding 13 is a three-phase connection, such as... Figure 1 As shown, they function as the U phase, V phase, and W phase, respectively. Furthermore, when power is supplied to the winding 13, a rotating magnetic field is generated in the stator 10 to drive the rotor 20 to rotate. In the stator 10 as described above, the outer peripheral surface of the stator core 11 is fixed relative to the inner peripheral surface of the outer casing 14.

[0012] (Structure of rotor 20) In this embodiment, the rotor 20 includes: a rotating shaft 21; a generally cylindrical rotor core 22 in which the rotating shaft 21 is embedded in the center; and eight permanent magnets 23 embedded inside the rotor core 22.

[0013] The rotor core 22 is made of a magnetic metal material. For example, the rotor core 22 is constructed by stacking multiple electromagnet steel plates in the direction of axis L1. The rotor 20 is configured to rotate relative to the stator 10 by having the rotating shaft 21 supported by a bearing disposed on the housing 14 (not shown).

[0014] The rotor core 22 has magnet receiving holes 24 for accommodating permanent magnets 23. In this embodiment, eight magnet receiving holes 24 are provided at equal intervals along the circumference of the rotor core 22. Each magnet receiving hole 24 has a roughly V-shaped folded-back shape that protrudes radially inward and is identical in shape to the others. Furthermore, the magnet receiving holes 24 are provided throughout the entire axial direction of the rotor core 22.

[0015] Here, the permanent magnet 23 of this embodiment is composed of a bonded magnet, which is formed by molding and hardening a magnetic material after mixing magnetic powder with resin. That is, the permanent magnet 23 is formed by using the magnet receiving hole 24 of the rotor core 22 as a molding die, and by injection molding the unhardened magnetic material into the magnet receiving hole 24 without gaps, and then hardening it within the magnet receiving hole 24 after filling. Therefore, the shape of the magnet receiving hole 24 becomes the outer shape of the permanent magnet 23. As the magnetic powder used in the permanent magnet 23 of this embodiment, for example, samarium iron nitride (SmFeN) type magnets are used, but other rare earth type magnets can also be used.

[0016] The permanent magnets 23 disposed within the magnet receiving holes 24 of the rotor core 22 are magnetized from the outside of the rotor core 22 using a magnetizing device (not shown) after the magnet material has hardened, so that they function as original magnets. In this embodiment, eight permanent magnets 23 are disposed circumferentially in the rotor core 22, and are magnetized by alternating different polarities in the circumferential direction. In addition, each permanent magnet 23 is magnetized in its own thickness direction.

[0017] Each permanent magnet 23 has a roughly V-shaped folded-back shape that protrudes radially inward. More specifically, as... Figure 2 As shown, the permanent magnet 23 has a shape in which the radially inner ends of a pair of straight portions 23a are connected to each other by a curved portion 23b. The radially outer end 23c of the straight portion 23a is located near the outer peripheral surface 22a of the rotor core 22.

[0018] The permanent magnet 23 is linearly symmetrical about its own circumferential centerline Ls with respect to the axis L1 passing through the rotor 20. Furthermore, the permanent magnet 23 is close to the magnetic pole boundary line Ld between adjacent permanent magnets 23 in the circumferential direction. Viewed from the direction of the axis L1, the magnetic pole boundary line Ld is a straight line dividing the magnetic pole portions 26 (described later), and is orthogonal to the axis L1.

[0019] The distance between the intersection of the extended inner surface of each straight section 23a of the V-shaped permanent magnet 23 and the outer peripheral surface 22a of the rotor core 22 is defined as the pole spacing Lp. The embedment depth Lm is defined as the distance from the outer peripheral surface 22a of the rotor core 22 to the inner surface of the curved section 23b along the circumferential centerline Ls of the permanent magnet 23. In this embodiment, the permanent magnet 23 is configured with a deeper folded shape, where the embedment depth Lm is greater than the pole spacing Lp. That is, the magnet surface 23d of the permanent magnet 23 of this embodiment, which is composed of the inner surfaces of each straight section 23a and the curved section 23b, is set to be larger than the magnet surface of a well-known surface magnet type (not shown). Furthermore, by setting the embedment depth Lm to be larger, the curved section 23b of the permanent magnet 23 is located near the radially inner side of the shaft insertion hole 22b for the insertion of the rotating shaft 21, close to the center of the rotor core 22. Furthermore, the folded shape of the permanent magnet 23 is one example, and it can be appropriately changed to a roughly U-shaped folded shape with a shallower embedment depth Lm or a larger bend 23b. Since the permanent magnet 23 has a roughly V-shaped folded shape that protrudes radially inward, it is easier to widen the radial area for the permanent magnet 23 to be installed compared to the above-described surface magnet type rotor.

[0020] The portion of the rotor core 22 located inside the V-shaped fold of the permanent magnet 23 and radially outward from the permanent magnet 23 functions as an outer core 25 for obtaining reluctance torque relative to the stator 10. When viewed axially, the outer core 25 has a roughly triangular shape with one vertex pointing towards the center of the rotor 20.

[0021] The rotor 20 has a plurality of magnetic pole portions 26 arranged circumferentially. Each of the plurality of magnetic pole portions 26 is configured to include a permanent magnet 23 and an outer core portion 25 surrounded by the V-shaped inner side of the permanent magnet 23. The plurality of magnetic pole portions 26 are formed at equal angular intervals in the circumferential direction.

[0022] The magnetic pole section 26 has a first end 26a, which is one circumferential end of the magnetic pole section 26, and a second end 26b, which is the other circumferential end of the magnetic pole section 26. The positions of the first end 26a and the second end 26b in the circumferential direction are respectively aligned with the magnetic pole boundary line Ld. In addition, when counterclockwise is defined as the forward rotation direction and clockwise is defined as the reverse rotation direction in the attached drawings, the end on the front side of the forward rotation direction of each magnetic pole section 26 is the second end 26b, and the end on the rear side of the forward rotation direction is the first end 26a.

[0023] In each magnetic pole section 26, the number of magnetic poles of the rotor 20, i.e., the number of magnetic pole sections 26, is set to P. The angle from the first end 26a to the second end 26b centered on the axis L1, i.e., the magnetic pole opening angle θm, is 360° / P. In the rotor 20 of this embodiment, the number of magnetic pole sections 26 is eight. Therefore, the magnetic pole opening angle θm of each magnetic pole section 26 is 45°. Figure 1 As shown, each magnetic pole portion 26 alternately functions as the N pole and S pole in the circumferential direction. In a rotor 20 having such magnetic pole portions 26, appropriate magnetic torque and reluctance torque can be obtained.

[0024] like Figure 3 As shown, an air gap Lg is provided between the outer peripheral surface 22a of the rotor core 22 and the front end face 12a of the pole tooth 12. Furthermore, the width of the front end face 12a of the pole tooth 12 is set to Lt, and the pole spacing Lp is set to satisfy Lt-(Lg×2)≤Lp≤Lt+(Lg×2). Additionally, the width Lt of the front end face 12a of the pole tooth 12 is the width of the front end face 12a in both the axial and radial directions. By setting the size of the pole spacing Lp within the above range, the size of the pole spacing Lp can be made approximately equal to the size of the front end face 12a of the pole tooth 12. As a result, the rotational torque of the rotor 20 can be obtained efficiently.

[0025] (Structure of slit 27) like Figure 1 As shown, each of the plurality of magnetic pole portions 26 has a slit 27 formed on the outer core portion 25. Each slit 27 is formed on the outer surface of the outer core portion 25. The slit 27 is, for example, a groove-shaped form on the outer surface of the outer core portion 25. That is, the slit 27 is formed to be recessed radially inward from the outer surface of the outer core portion 25. Furthermore, the outer surface of the outer core portion 25 is part of the outer peripheral surface 22a of the rotor core portion 22. Additionally, the slit 27 is, for example, formed as a straight line along the axis L1.

[0026] (Regarding the position setting of the slits 27 in each magnetic pole section 26) like Figure 4 As shown, six regions are arranged circumferentially in each magnetic pole section 26. Specifically, the magnetic pole section 26 is divided into twelve equal regions circumferentially. Then, counting sequentially from the direction closest to the first end 26a in a clockwise direction, the fourth to ninth regions are designated as first region A, second region B, third region C, fourth region D, fifth region E, and sixth region F, respectively. The opening angle of each region A to F, centered on the axis L1, is the angle of twelve equal divisions of the magnetic pole opening angle θm, which is 3.75° in this embodiment. First region A to sixth region F are, for example, set within the range of the magnetic pole spacing Lp.

[0027] In each magnetic pole section 26, the slit 27 is positioned such that its circumferential center Lc is located in any one of regions A to F. Figure 4In the example shown, a slit 27 provided in the magnetic pole section 26 is indicated by a double-dotted line. This slit 27 is provided such that its circumferential center Lc is located within the third region C. Furthermore, for ease of explanation, the description of the circumferential center Lc will be omitted below, and the case where the circumferential center Lc of each slit 27 is located in any one of the regions A to F will be simply explained as "the slit 27 is located in the region".

[0028] Figure 5 An example of the arrangement of slits 27 in each magnetic pole section 26 is shown. As shown in the figure, the eight slits 27 respectively provided in the eight magnetic pole sections 26 include at least one first slit 27a and at least one second slit 27b. The first slit 27a is either the slit 27 disposed in the third region C or the slit 27 disposed in the sixth region F. The second slit 27b is disposed in any one of the first region A, the second region B, the third region C, the fourth region D, the fifth region E, and the sixth region F. Furthermore, in Figure 5 In the diagram, the symbol for the configuration area of ​​the slit 27 is marked on the outer periphery of each magnetic pole portion 26.

[0029] As shown in the figure, there are two slits 27 arranged in the first region A. There are zero slits 27 arranged in the second region B. There is one slit 27 arranged in the third region C. There are two slits 27 arranged in the fourth region D. There are zero slits 27 arranged in the fifth region E. Furthermore, there are three slits 27 arranged in the sixth region F. In addition, each slit 27... Figure 5 The slits 27 of the upper magnetic pole portion 26 are sequentially arranged in the first region A, third region C, fourth region D, and sixth region F in the clockwise direction (counterclockwise direction). The order of the circumferential arrangement regions of each slit 27 is not limited to this embodiment and can be appropriately changed. Furthermore, in Figure 5 In the structure shown, there are regions A through F where no slit 27 is configured. In this example, the regions without slit 27 are the second region B and the fifth region E.

[0030] (Regarding the torque pulse of the 24th order rotating component) The second slit 27b is positioned to generate a torque pulse that is in the opposite phase to the torque pulse of the rotating (3×P)-order component generated by the first slit 27a. In the rotor 20 of this embodiment, the number of magnetic poles P is 8. Therefore, the second slit 27b is positioned to generate a torque pulse that is in the opposite phase to the torque pulse of the rotating 24th-order component generated by the first slit 27a.

[0031] Figure 6The diagram illustrates the relationship between the position and phase of the slit 27, representing the 24th-order rotating torque pulse. As shown, the phase width of slit 27 as its position changes from one end of the first region A to the other is approximately 75°, ranging from approximately 195° to approximately 270°. The phase width of slit 27 as its position changes from one end of the second region B to the other is approximately 60°, ranging from approximately 270° to approximately 330°. The phase width of slit 27 as its position changes from one end of the third region C to the other is approximately 210°, ranging from approximately 330° to approximately 180°. The phase width of slit 27 as its position changes from one end of the fourth region D to the other is approximately 50°, ranging from approximately 180° to approximately 230°. The phase width of slit 27 as its position changes from one end of the fifth region E to the other is approximately 80°, ranging from approximately 230° to approximately 310°. Furthermore, the phase width of slit 27 as its position changes from one end of the sixth region F to the other ranges from approximately 310° to approximately 75°, approximately 125°. As described above, among regions A to F, the only regions where the phase width of slit 27 as its position changes within the range exceeds 90° are the third region C and the sixth region F.

[0032] The second slit 27b is positioned to generate a torque pulse with an opposite phase to the torque pulse of the 24th-order rotating component generated by the first slit 27a, i.e., a phase difference of 180°. Thus, the torque pulses of the 24th-order rotating component generated by the first slit 27a and the second slit 27b respectively weaken each other through mutual interference. As a result, the torque pulse of the 24th-order rotating component can be suppressed to a smaller size.

[0033] For example, such as Figure 6 As shown, assume that in one of the magnetic pole portions 26, the first slit 27a is positioned at a first position X1 within the third region C. The torque pulse generated by the first slit 27a positioned at the first position X1 has a phase of 60°, which is the 24th order rotational component. Therefore, the second slit 27b is set at either a second position X2 or a third position X3, which generates a torque pulse with a phase difference of 180°, or 240°, relative to 60°. The second position X2 is a position within the first region A, and the third position X3 is a position within the fifth region E. In this way, the positions of the first slit 27a and the second 27b, which generate torque pulses with opposite phases of the 24th order rotational component, are set.

[0034] The phase width of the third region C and the sixth region F is 90° or more, which is larger than that of the other regions. Therefore, by setting at least one of the slits 27 of each magnetic pole portion 26 as a first slit 27a disposed in the third region C or the sixth region F, the degree of freedom in setting the position of the second slit 27b that generates a torque pulse with opposite phase relative to the first slit 27a can be increased.

[0035] (Regarding the torque pulse of the 48th order rotating component) Furthermore, the second slit 27b is positioned to generate a torque pulse with an opposite phase to the torque pulse of the rotating (6×P)-order component generated by the first slit 27a. In the rotor 20 of this embodiment, the number of magnetic poles P is 8. Therefore, the second slit 27b is positioned to generate a torque pulse with an opposite phase to the torque pulse of the rotating 48th-order component generated by the first slit 27a. As a result, the rotating 48th-order component torque pulses generated by the first slit 27a and the second slit 27b respectively weaken each other by interfering with each other. Consequently, the rotating 48th-order component torque pulse can be suppressed to a smaller size.

[0036] Figure 7 The diagram illustrates the relationship between the position and phase of the slit 27 of the torque pulse with a 48th-order rotational component. As shown in the diagram, in the first region A, the third region C, and the fifth region E, the phase width of the slit 27 as its position changes from one end of the region to the other ranges from approximately 0° to approximately 180°. Furthermore, in the second region B, the fourth region D, and the sixth region F, the phase width of the slit 27 as its position changes from one end of the region to the other ranges from approximately 180° to approximately 360°.

[0037] Therefore, relative to the first slit 27a disposed in the third region C, the second slit 27b, which generates a torque pulse with a 48th-order rotating component of opposite phase, is disposed in any one of the second region B, the fourth region D, and the sixth region F. Furthermore, relative to the first slit 27a disposed in the sixth region F, the second slit 27b, which generates a torque pulse with a 48th-order rotating component of opposite phase, is disposed in any one of the first region A, the third region C, and the fifth region E.

[0038] exist Figure 8 The table illustrates twenty-two patterns that significantly reduce torque pulses in the arrangement of slits 27 in each pole section 26. The table also shows the number of slits 27 arranged in each of the twenty-two patterns, from the first region A to the sixth region F. Furthermore, P in the table represents the number of poles of the rotor 20. Additionally, the number of slits 27 when the number of poles P of the rotor 20 is 8 is shown in parentheses within the table.

[0039] The reduction effect of each pattern in the table represents the proportion of the reduction in torque pulses relative to the rotor of the comparative structure described later. The rotor of the comparative structure is a structure from the rotor 20 of this embodiment with each slit 27 omitted. That is, viewed from the axial direction, the rotor of the comparative structure has a circular structure with no protrusions or depressions on the outer peripheral surface 22a of the rotor core 22.

[0040] The above Figure 5The configuration pattern of each slit 27 in the rotor 20 shown is contained in Figure 8 Pattern 4 is one of the twenty-two patterns shown in the table. In pattern 4, the torque pulse is reduced by 90% compared to the comparison structure. Among the twenty-two patterns, pattern 4 has the best torque pulse reduction effect.

[0041] like Figure 8 As shown, in patterns 3, 5, and 9 out of the twenty-two patterns, the torque pulse is reduced by 85% compared to the comparison structure. In patterns 1, 2, 10, 11, and 13 out of the twenty-two patterns, the torque pulse is reduced by 80% compared to the comparison structure. In patterns 6, 7, 8, 12, 15, 18, 19, and 20 out of the twenty-two patterns, the torque pulse is reduced by 75% compared to the comparison structure. In patterns 14, 16, and 17 out of the twenty-two patterns, the torque pulse is reduced by 70% compared to the comparison structure. In pattern 22 out of the twenty-two patterns, the torque pulse is reduced by 65% ​​compared to the comparison structure. Furthermore, in pattern 21 out of the twenty-two patterns, the torque pulse is reduced by 35% compared to the comparison structure.

[0042] Figure 9 The rotor 20 is shown with the arrangement of each slit 27 as shown in pattern 3. When the number of magnetic poles P of the rotor 20 is 8, in pattern 3, there are two slits 27 arranged in the first region A. Furthermore, there are zero slits 27 arranged in the second region B. There are two slits 27 arranged in the third region C. There is one slit 27 arranged in the fourth region D. There are zero slits 27 arranged in the fifth region E. Moreover, there are three slits 27 arranged in the sixth region F. Furthermore, each slit 27... Figure 9 The slits 27 of the upper magnetic pole portion 26 are arranged sequentially in the first region A, the sixth region F, the third region C, the fourth region D, the sixth region F, the first region A, the sixth region F, and the third region C, respectively, in the clockwise direction (counterclockwise direction). The circumferential arrangement order of the slits 27 is not limited to... Figure 9 The example shown can be modified as appropriate.

[0043] Figure 10 The rotor 20 is shown with the arrangement of each slit 27 as pattern 5. When the number of magnetic poles P of the rotor 20 is 8, in pattern 5, the number of slits 27 arranged in the first region A is zero. Furthermore, the number of slits 27 arranged in the second region B is zero. The number of slits 27 arranged in the third region C is two. The number of slits 27 arranged in the fourth region D is three. The number of slits 27 arranged in the fifth region E is zero. Moreover, the number of slits 27 arranged in the sixth region F is three. Furthermore, each slit 27... Figure 10The slits 27 of the upper magnetic pole portion 26 are sequentially arranged in the third region C, the sixth region F, the third region C, the fourth region D, the sixth region F, the fourth region D, and the sixth region F, respectively, in the clockwise direction (counterclockwise direction). The circumferential arrangement order of the slits 27 is not limited to... Figure 10 The example shown can be modified as appropriate.

[0044] Figure 11 The rotor 20 is shown with each slit 27 arranged in pattern 8. When the number of magnetic poles P of the rotor 20 is 8, in pattern 8, there are two slits 27 arranged in the first region A. Furthermore, there are two slits 27 arranged in the second region B. There are two slits 27 arranged in the third region C. There are zero slits 27 arranged in the fourth region D. There are zero slits 27 arranged in the fifth region E. Moreover, there are two slits 27 arranged in the sixth region F. Furthermore, each slit 27... Figure 11 The slits 27 of the upper magnetic pole portion 26 are arranged sequentially in the first region A, the third region C, the sixth region F, the second region B, the first region A, the third region C, the sixth region F, and the second region B in the forward rotation direction (counterclockwise direction).

[0045] exist Figure 11 In the structure shown, the arrangement regions of the slits 27 in the paired magnetic pole portions 26 arranged on opposite sides at 180° are identical. Specifically, the magnetic pole portions 26 with slits 27 in the first region A are positioned 180° opposite each other. Furthermore, the magnetic pole portions 26 with slits 27 in the second region B are positioned 180° opposite each other. Additionally, the magnetic pole portions 26 with slits 27 in the third region C are positioned 180° opposite each other. Moreover, the magnetic pole portions 26 with slits 27 in the sixth region F are positioned 180° opposite each other. This reduces radial magnetic imbalance and mass imbalance in the rotor 20.

[0046] The effects of this implementation method will be explained. (1) The plurality of magnetic pole portions 26 of the rotor 20 each have a slit 27 formed in the rotor core portion 22. The plurality of slits 27 include a first slit 27a and a second slit 27b. The first slit 27a is disposed in the third region C or the sixth region F. Moreover, the second slit 27b is disposed in any one of the first region A, the second region B, the third region C, the fourth region D, the fifth region E and the sixth region F.

[0047] According to this structure, the width of the phase of the torque pulse when the position of slit 27 changes circumferentially is larger in the third region C and the sixth region F than in other regions (see reference). Figure 6Therefore, by including a first slit 27a disposed in the third region C or the sixth region F, the degree of freedom in setting the position of the second slit 27b, which generates torque pulses with opposite phase relative to the first slit 27a, can be improved among the plurality of slits 27. Furthermore, according to the above embodiment, since the number of slits 27 formed on a single magnetic pole portion 26 is one, the reduction in rotational torque caused by the provision of the slits 27 can be suppressed to a great extent.

[0048] (2) The second slit 27b is located in any one of the first region A, the second region B, the third region C, the fourth region D, the fifth region E and the sixth region F, at a position that generates a torque pulse with the opposite phase to the torque pulse of the rotating (3×P) order component generated by the first slit 27a.

[0049] According to this structure, in the torque pulse of the rotating (3×P) order component, the torque pulse generated by the first slit 27a and the torque pulse generated by the second slit 27b weaken each other. Therefore, it is possible to suppress the increase of the torque pulse of the rotating (3×P) order component.

[0050] (3) Viewed axially, each permanent magnet 23 has a folded-back shape that protrudes radially inward toward the rotor 20. This structure allows for a larger surface area of ​​the permanent magnet 23 facing the outer core 25. This increases the magnet torque. Furthermore, this structure allows for a larger volume of the outer core 25. This increases the reluctance torque. As a result, it contributes to achieving high torque in the rotating electric motor M.

[0051] (4) In the outer peripheral surface 22a of the rotor core 22, the distance between the extension lines of the inner surfaces of the folded permanent magnets 23 is set as the pole spacing Lp, and the first region A, the second region B, the third region C, the fourth region D, the fifth region E, and the sixth region F are set within the range of the pole spacing Lp. Thus, the slit 27 can be set within the range of the pole spacing Lp.

[0052] (5) The plurality of slits 27 includes a first slit 27a disposed in the third region C. Furthermore, a second slit 27b is disposed in any one of the second region B, the fourth region D, and the sixth region F at a position that generates a torque pulse with an opposite phase to the torque pulse of the rotating (6×P) order component generated by the first slit 27a. According to this structure, in the torque pulse of the rotating (6×P) order component, the torque pulse generated by the first slit 27a and the torque pulse generated by the second slit 27b mutually weaken each other. Therefore, it is possible to suppress the amplification of the torque pulse of the rotating (6×P) order component.

[0053] (6) The plurality of slits 27 includes a first slit 27a disposed in the sixth region F. Furthermore, a second slit 27b is disposed in any one of the first region A, the third region C, and the fifth region E at a position that generates a torque pulse with an opposite phase to the torque pulse of the rotating (6×P) order component generated by the first slit 27a. According to this structure, in the torque pulse of the rotating (6×P) order component, the torque pulse generated by the first slit 27a and the torque pulse generated by the second slit 27b mutually weaken each other. Therefore, it is possible to suppress the amplification of the torque pulse of the rotating (6×P) order component.

[0054] (7) In at least one of the regions A to F, a region without slits 27 is set in any one of the plurality of magnetic pole sections 26. As a result, the torque pulses of the rotating (3×P) order components generated at each slit 27 interfere with each other appropriately, and the torque pulses of the rotating (3×P) order components can be appropriately reduced.

[0055] For example, in the above embodiment, it is assumed that the slit 27 is disposed in a first region A in a certain magnetic pole portion 26, and disposed in a second region B in another magnetic pole portion 26. In the torque pulse of the 24th order rotational component, the phase width of the first region A is approximately 195° to approximately 270°, and the phase width of the second region B is approximately 270° to approximately 330° (refer to...). Figure 6 Therefore, in the 24th-order rotational component, the torque pulse generated by the slit 27 disposed in the first region A and the torque pulse generated by the slit 27 disposed in the second region B cannot achieve a 180° phase difference. Therefore, in either the first region A or the second region B, a region without the slit 27 is provided in any of the plurality of magnetic pole portions 26, thereby appropriately reducing the torque pulse of the 24th-order rotational component. Furthermore, this is also true in the fourth region D and the fifth region E. That is, in either the fourth region D or the fifth region E, a region without the slit 27 is provided in any of the plurality of magnetic pole portions 26, thereby appropriately reducing the torque pulse of the 24th-order rotational component.

[0056] (8) In the paired magnetic pole sections 26 arranged on opposite sides at 180°, by making the arrangement areas of the slits 27 identical, the radial magnetic imbalance and mass imbalance of the rotor 20 can be reduced.

[0057] (Modified Example) This embodiment can be modified and implemented in the following ways. This embodiment and the following variations can be combined and implemented to the extent that they are not technically contradictory.

[0058] • In the rotor 20 of the above embodiment, the core sheets constituting the rotor core 22 may be stacked while rotating. For example, such as Figure 12 and Figure 13 As shown, the rotor core 22 is formed by multiple core plates 30 stacked along the axial direction. Each core plate 30 is, for example, made of electromagnetic steel sheet.

[0059] Multiple slits 27, including a first slit 27a and a second slit 27b, are respectively provided on multiple core sheets 30. The multiple core sheets 30 have identical structures; that is, the arrangement of the multiple slits 27 in each core sheet 30 is identical. Figure 12 and Figure 13 In the structure shown, each core sheet 30 is, for example, Figure 5 The configuration of slit 27 in pattern 4 shown.

[0060] The rotor core 22 is formed by stacking core plates 30 in a manner where each plate rotates (360° / P)°. Figure 12 In this process, the topmost core sheet 30 is designated as the first-layer core sheet 30a, the core sheet 30 below the first-layer core sheet 30a is designated as the second-layer core sheet 30b, and the core sheet 30 below the second-layer core sheet 30b is designated as the third-layer core sheet 30c.

[0061] In this example, the second-layer core sheet 30b is rotated 45° clockwise relative to the first-layer core sheet 30a. Similarly, the third-layer core sheet 30c is rotated 45° clockwise relative to the second-layer core sheet 30b. The core sheets 30 in layers 30 and beyond are also rotated 45° clockwise relative to the previous layer's core sheet 30.

[0062] In each magnetic pole portion 26 of the rotor 20, which is composed of multiple core sheets 30 stacked in the manner described above, the positions of the slits 27 are not a straight line along the axial direction. For example, in Figure 12 In the upper magnetic pole section 26, the positions of the slits 27 of each core sheet 30, starting from the first layer, are: first region A, third region C, fourth region D, sixth region F, first region A, fourth region D, sixth region F, sixth region F...

[0063] As described above, by stacking the core sheets 30 while rotating (360° / P)°, the positions of the slits 27 in each magnetic pole section 26 can be configured to be non-constant. This reduces radial magnetic imbalance and mass imbalance in the rotor 20. Furthermore, it reduces axial magnetic imbalance in the rotor 20. Additionally, by stacking the core sheets 30 while rotating (360° / P)°, the torque pulses of the S-order rotational component can be reduced in a rotary motor M with S slots. For example, when the number of slots S is 12, the torque pulses of the 12th-order rotational component can be reduced.

[0064] In the example above, each core chip 30 is Figure 5The configuration of slit 27 in pattern 4 shown can also be, for example, [other configurations]. Figure 14 The configuration of slit 27 is shown. like Figure 14 As shown, the slits 27 in each core sheet 30 are Figure 8 The structure of pattern 9 in the table. When the number of magnetic poles P of rotor 20 is 8, in pattern 9, the number of slits 27 arranged in the first region A is two. Furthermore, the number of slits 27 arranged in the second region B is two. The number of slits 27 arranged in the third region C is one. The number of slits 27 arranged in the fourth region D is one. The number of slits 27 arranged in the fifth region E is zero. Then, the number of slits 27 arranged in the sixth region F is two. Furthermore, each slit 27... Figure 14 The slits 27 of the upper magnetic pole portion 26 are arranged sequentially in the first region A, the second region B, the third region C, the fourth region D, the sixth region F, and the sixth region F in the forward rotation direction (counterclockwise direction).

[0065] Figure 15 It shows that Figure 14 The rotor 20 is formed by stacking core sheets 30, each rotated (360° / P)° clockwise. Figure 15 The rotor 20 shown has a skewed portion 40 formed on it, where the slits 27 of each core plate 30 are circumferentially displaced in the axial direction. In the above structure, the skewed portion 40 is formed by setting the arrangement regions of the slits 27 of each magnetic pole portion 26 in ascending or descending order along the forward rotation direction. Figure 14 and Figure 15 In the structure shown, for example, the slits 27 of the magnetic pole portions 26 adjacent to the slits 27 in the first region A in the forward rotation direction are arranged in any one of the first regions A to the sixth region F. Furthermore, the slits 27 of the magnetic pole portions 26 adjacent to the slits 27 in the second region B in the forward rotation direction are arranged in any one of the second regions B to the sixth region F. Furthermore, the slits 27 of the magnetic pole portions 26 adjacent to the slits 27 in the third region C in the forward rotation direction are arranged in any one of the third regions C to the sixth region F. Furthermore, the slits 27 of the magnetic pole portions 26 adjacent to the slits 27 in the fourth region D in the forward rotation direction are arranged in any one of the fourth regions D to the sixth region F. According to this structure, the torque pulses can be more appropriately reduced by the skewed portions 40 formed by the slits 27 of each core sheet 30. Furthermore, the twisted portion 40 can reduce radial and axial magnetic imbalance and mass imbalance.

[0066] Furthermore, the configuration of the slit 27 forming the twisted portion 40 in the stacked state is not limited to... Figure 14The configuration shown. For example, the slits 27 of each magnetic pole portion 26 can also be arranged sequentially along the forward rotation direction as first region A, second region B, third region C, sixth region F, first region A, second region B, fourth region D, and sixth region F. With such a configuration, a skewed portion can also be formed through the slits 27 of each core sheet 30. Furthermore, even when the number of slits 27 in each region A to F is set to a certain value... Figure 14 Even with different numbers of the structures shown, a twisted portion can be formed through the slits 27 of each core sheet 30.

[0067] In addition, Figures 12-15 In the example shown, the core sheets 30 are stacked in a state of rotation of (360° / P)° per sheet, but are not limited to this, for example, as Figure 16 As shown, the core sheet 30 can also be stacked in a state where every two or more sheets are rotated (360° / P)°. Figure 16 As an example, it is shown in the text. Figure 14 The rotor 20 is formed by stacking three core sheets 30 in a manner that rotates (360° / P)° at a time. Furthermore, in Figure 16 In the structure shown, the slits 27 of each core sheet 30 form a skewed portion 40. This structure also reduces radial and axial magnetic imbalance and mass imbalance through the skewed portion 40. Furthermore, in a rotary motor M with S slots, the torque pulse of the S-order rotational component can be reduced. For example, when the number of slots S is 12, the torque pulse of the 12th-order rotational component can be reduced.

[0068] In the above embodiments, for example, it is also possible to... Figure 17 The shape of the outer peripheral surface 22a of the rotor core 22, when viewed from the axial direction, is altered. Figure 17 In the structure shown, the outer peripheral surface 22a of the rotor core 22, viewed axially, has a shape that is radially inwardly displaced from the circumferential center line Ls of the magnetic pole section 26 toward the magnetic pole boundary lines Ld on both sides. That is, the outer diameter of the rotor core 22, i.e., the distance from the axis L1 to the outer peripheral surface 22a of the rotor core 22, is different in the circumferential direction. Specifically, the outer diameter of the rotor core 22 is largest at the circumferential center line Ls of each magnetic pole section 26 and smallest at the magnetic pole boundary lines Ld. Figure 17 In the diagram, a circle with the same diameter as the maximum diameter of the rotor core 22 is designated as the reference circle Ca. Furthermore, when viewed axially, the radially outer surface of each magnetic pole portion 26 is an arc shape with a diameter smaller than that of the reference circle Ca.

[0069] according to Figure 17 In the structure shown, the radially outer surface of the magnetic pole section 26 is shaped to be displaced radially inward from the circumferential center line Ls toward the magnetic pole boundary lines Ld on both sides, thus making the switching of magnetic poles smooth. As a result, torque pulses can be suppressed to a smaller extent.

[0070] • The slit 27 in the above embodiment is a groove shape with the radially outer end open. Alternatively, it may be a slit shape with the radially outer end closed. • The arrangement of the slits 27 in each magnetic pole portion 26 is not limited to the twenty-two patterns 1 to 22 shown in the above embodiments. The slits 27 in each magnetic pole portion 26 can also be structures other than patterns 1 to 22, as long as they have a structure with a first slit 27a and a second slit 27b, and the first slit 27a is arranged in the third region C or the sixth region F, and the second slit 27b generates a torque pulse with a torque pulse that is opposite in phase to the torque pulse of the rotating (3×P) order component generated by the first slit 27a.

[0071] • The setting of the first region A to the sixth region F is not limited to the above-described embodiment. For example, the magnetic pole portion 26 may be divided into twelve regions along the circumference, and the ranges of the fourth to ninth regions when counting sequentially from the direction closest to the second end 26b in reverse direction may be respectively designated as the first region A, the second region B, the third region C, the fourth region D, the fifth region E, and the sixth region F.

[0072] The number of magnetic poles P of rotor 20 is not limited to eight in the above embodiment, and the number of magnetic poles P can also be set to seven or less or nine or more. The permanent magnet 23 is not limited to a V-shape, but can also be a U-shape or other folded-back shape that protrudes radially inward from the equilateral rotor 20. Alternatively, it can be a shape other than an I-shape or other folded-back shape.

[0073] • A permanent magnet 23 is formed by injection molding a magnet material into the magnet receiving hole 24 of the rotor core 22. Alternatively, the permanent magnet 23 can be prefabricated and inserted into the magnet receiving hole 24 of the rotor core 22 and fixed.

[0074] In addition to the above, the structure of rotor 20 and rotary motor M can also be appropriately modified. While this disclosure has been described based on embodiments, it should be understood that this disclosure is not limited to the above embodiments and structures. This disclosure also includes various modifications and equivalent variations. Furthermore, various combinations and arrangements, and consequently, combinations and arrangements containing only one element, or more or less thereof, also fall within the scope and spirit of this disclosure.

[0075] (Postscript) The features of this disclosure are as follows. [1] The rotary electric motor (M) includes: a rotor (20) having a rotor core (22) and a permanent magnet (23) embedded in the rotor core; and a stator (10) applying a rotating magnetic field to the rotor, and having a plurality of magnetic pole portions (26) formed at equal angular intervals in the circumferential direction on the rotor, each magnetic pole portion having a slit (27) formed in the rotor core, the number of magnetic pole portions being P, and the angle from one circumferential end (26a) to the other circumferential end (26b) of each magnetic pole portion being 360° / P, and the angle from the circumferential end (26a) to the other circumferential end (26b) of each magnetic pole portion being P. When the circumferential end to the other end is divided into twelve regions, the fourth to ninth regions, which are counted sequentially from the side closest to the circumferential end, are respectively designated as the first region (A), the second region (B), the third region (C), the fourth region (D), the fifth region (E), and the sixth region (F). The plurality of slits includes a first slit (27a) and a second slit (27b). The first slit is disposed in the third region or the sixth region, and the second slit is disposed in any one of the first region, the second region, the third region, the fourth region, the fifth region, and the sixth region.

[0076] [2] As described in [1], the second slit is located in any one of the first region, the second region, the third region, the fourth region, the fifth region and the sixth region, at a position that generates a torque pulse with the opposite phase to the torque pulse of the rotational (3×P) order component generated by the first slit.

[0077] [3] As described in [1] or [2], each permanent magnet has a folded shape that protrudes radially inward toward the rotor. [4] As described in [3], on the outer peripheral surface of the rotor core, the extension lines of the inner side surfaces of the folded permanent magnets are set as the magnetic pole spacing (Lp), and the first region, the second region, the third region, the fourth region, the fifth region and the sixth region are set within the range of the magnetic pole spacing.

[0078] [5] The rotary motor as described in any one of [1] to [4], wherein the first slit is disposed in the third region, and the second slit is disposed in any one of the second region, the fourth region and the sixth region at a position that generates a torque pulse with the opposite phase to the torque pulse of the rotational (6×P) order component generated by the first slit.

[0079] [6] The rotary motor as described in any one of [1] to [5], wherein the first slit is disposed in the sixth region, and the second slit is disposed in any one of the first region, the third region and the fifth region at a position that generates a torque pulse with the opposite phase to the torque pulse of the rotational (6×P) order component generated by the first slit.

[0080] [7] The rotary motor as described in any one of [1] to [6] has a region in which the slit is not configured in any one of the plurality of magnetic pole portions in at least one of the first region, the second region, the third region, the fourth region, the fifth region and the sixth region.

[0081] [8] In any one of the rotary electric motors described in [1] to [7], the slit configuration areas are identical in the pairs of magnetic pole portions arranged on opposite sides at 180°. [9] The rotary motor as described in any one of [1] to [8], wherein the rotor core is formed by a plurality of core plates (30) stacked axially, the plurality of core plates having the same structure, and the plurality of slits including the first slit and the second slit are respectively provided on the plurality of core plates, and the rotor core is formed by stacking the core plates in a state of rotating (360° / P)° at intervals of a predetermined number of plates.

[0082]

[10] As described in [9], the rotor core is formed by stacking the core sheets in a state of rotating (360° / P)° per sheet.

[11] As described in [9] or

[10] , in a state in which multiple core sheets are stacked, the multiple slits in the core sheets are configured to form a skew portion (40) in which the slits of each core sheet are axially displaced in the circumferential direction.

Claims

1. A rotating electrical machine, the rotating electrical machine (M) comprising: A rotor (20), the rotor comprising a rotor core (22) and a permanent magnet (23) embedded in the rotor core; as well as a stator (10), the stator applying a rotating magnetic field to the rotor, A plurality of magnetic pole portions (26) including the permanent magnet and a portion of the rotor core are formed on the rotor at equal angular intervals in the circumferential direction. Each of the plurality of magnetic poles has a slit (27) formed in the rotor core. The number of the magnetic poles is set to P, and the angle from one circumferential end (26a) to the other circumferential end (26b) of each magnetic pole is 360° / P. When the magnetic pole portion is equally divided into twelve regions from one circumferential end to the other circumferential end, the fourth to ninth regions of the twelve regions, when counted sequentially from the side close to the one circumferential end, are respectively designated as the first region (A), the second region (B), the third region (C), the fourth region (D), the fifth region (E) and the sixth region (F), The plurality of slits include a first slit (27a) and a second slit (27b), The first slit is arranged in the third region or the sixth region, The second slit is disposed in any one of the first region, the second region, the third region, the fourth region, the fifth region, and the sixth region.

2. The rotating electrical machine according to claim 1, characterized in that: The second slit is arranged at a position in any one of the first region, the second region, the third region, the fourth region, the fifth region, and the sixth region to generate a torque pulse having a phase opposite to that of a torque pulse of a rotation 3×P-order component generated by the first slit.

3. The rotating electrical machine according to claim 1, characterized in that: Each of the permanent magnets has a folded shape that protrudes radially inwardly of the rotor.

4. The rotating electrical machine according to claim 3, characterized in that: On the outer peripheral surface of the rotor core, the extension lines of the inner side surfaces of the folded permanent magnets are set as the magnetic pole pitch (Lp). The first region, the second region, the third region, the fourth region, the fifth region, and the sixth region are set within the range of the magnetic pole pitch.

5. The rotating electrical machine according to claim 1, characterized in that: The first slit is arranged in the third area, The second slit is arranged at a position in any one of the second region, the fourth region, and the sixth region where a torque pulse having a phase opposite to that of a torque pulse of a rotational 6×P-order component generated by the first slit is generated.

6. The rotating electrical machine according to claim 1, characterized in that: The first slit is arranged in the sixth region, The second slit is arranged at a position in any one of the first region, the third region, and the fifth region at which a torque pulse having a phase opposite to that of a torque pulse of a rotational 6×P-order component generated by the first slit is generated.

7. The rotating electrical machine according to claim 1, characterized in that In at least one of the first region, the second region, the third region, the fourth region, the fifth region, and the sixth region, a region in which the slit is not arranged is set in any of the plurality of magnetic pole portions.

8. The rotating electrical machine according to claim 1, characterized in that In the pair of magnetic pole portions arranged on 180° opposite sides, the arrangement regions of the slits are the same as each other.

9. The rotating electrical machine according to claim 1, characterized in that The rotor core is formed by a plurality of core sheets (30) stacked axially. The plurality of core sheets have the same structure as each other, A plurality of slits including the first slit and the second slit are respectively provided on the plurality of core sheets, The rotor core is formed by stacking the core sheets in a state where the core sheets are rotated by (360° / P)° every a predetermined number of sheets.

10. The rotating electrical machine according to claim 9, characterized in that The rotor core is formed by stacking the core sheets with each sheet rotated by (360° / P)°.

11. The rotating electrical machine according to claim 9 or 10, characterized in that: In a state where a plurality of the core sheets are stacked, a plurality of the slits in the core sheets are arranged to form a skewed portion (40) in which the slits of each of the core sheets are displaced in the axial direction and in the circumferential direction.

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