JP2017055560A - Permanent magnet type rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for reducing a cogging torque or a torque ripple without reduction of a torque even if a groove is provided between magnetic poles constructed to a rotor.SOLUTION: A permanent magnet type rotary electric machine comprises: a stator having a plurality of teeth protrusively formed from an annular stem part toward a radial direction side; and a rotor having a plurality of magnetic poles constructed by at least one permanent magnet. The rotor includes: a first groove part formed in an axial direction of the rotor in a circumference on a q-axis electrically intersecting a d-axis formed by one magnetic pole; and a second groove which is continuously formed in the first groove in the d-axial side outer than the first groove part and is formed in the axial direction of rotor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a permanent magnet type rotating electrical machine.

  Conventionally, in a rotor configured with a plurality of magnetic poles, grooves are formed on the outer periphery between the magnetic poles, and one magnetic pole sandwiched between the grooves is formed to have a convex shape in the outer peripheral direction, thereby reducing the induced voltage. A rotor capable of reducing cogging torque or torque ripple has been disclosed (see Patent Document 1).

JP2012-16189A

  By the way, in the structural design of the rotor, it is necessary to secure a rotor core width enough to withstand centrifugal force on the outer peripheral side of the permanent magnet embedded in the rotor from the viewpoint of anti-centrifugal strength. Therefore, in the rotor disclosed in Patent Document 1, it is necessary to dispose the permanent magnet on the inner peripheral side by providing the groove, so that the magnet magnetic flux linked to the stator is weakened and the torque is reduced. End up.

  Further, the technique disclosed in Patent Document 1 does not mention the shape of the stator teeth for the above-described rotor. However, depending on the shape of the stator teeth, the cogging torque reduction effect due to the grooves provided in the rotor may not be sufficiently obtained.

  An object of the present invention is to provide a technique capable of reducing cogging torque or torque ripple without reducing torque even when a groove is provided between magnetic poles formed on a rotor.

  A permanent magnet type rotating electrical machine according to the present invention includes a stator having a plurality of teeth formed to project radially inward from an annular base portion, and a rotor having a plurality of magnetic poles made of at least one permanent magnet. The rotor has a first groove portion formed along the axial direction of the rotor on the outer periphery on the q-axis that is electrically orthogonal to the d-axis formed by one magnetic pole, and the outer periphery on the d-axis side from the first groove portion. And a second groove portion provided continuously with the first groove portion and formed along the axial direction of the rotor.

  According to the present invention, in addition to the first groove portion provided on the q-axis, the second groove portion provided continuously to the first groove portion is formed on the outer periphery on the d-axis side from the first groove portion. By doing so, it is possible to secure a rotor core width that satisfies the anti-centrifugal strength at the connection portion between the first groove portion and the second groove portion, and to dispose the permanent magnet on the outer periphery side of the rotor. Cogging torque or torque ripple can be reduced without a decrease.

FIG. 1 is a view for explaining an embodiment of a permanent magnet type rotating electrical machine according to the present invention. FIG. 2 is a diagram for explaining an index used to define the shapes of the first groove, the second groove, and the connecting portion. FIG. 3 is a diagram comparing a general rotor shape of an IPM motor and a rotor shape according to a conventional example in which grooves are provided on the outer periphery, and a rotor shape according to an embodiment. FIG. 4 is a diagram for comparing the maximum torque of each of the three rotor shapes shown in FIG. FIG. 5 is a view for explaining the convex width θ1 of the rotor and the width θ2 of the tip of the tooth. FIG. 6 is a diagram showing a torque ripple analysis value when the width of the convex portion θ1 of the rotor and the tip width θ2 of the teeth are changed under load. FIG. 7 is a diagram showing the relationship between the tooth tip width θ2 and the cogging torque. FIG. 8 is a diagram showing the cogging torque analysis value when the convex portion width θ1 of the rotor and the tip width θ2 of the teeth are changed in the no-load state. FIG. 9 is a view for explaining the shape of the notch formed in the tooth according to the embodiment. FIG. 10 is a diagram showing a cogging torque analysis value when the tooth convex portion width θ3 is changed at no load. FIG. 11 is a diagram showing analysis values of cogging torque and torque ripple when the gap width dg is constant and the depth d2 of the second groove is changed when there is no load and when there is a load. FIG. 12 is a diagram for explaining the rotor shape of the first modification. FIG. 13 is a view for explaining the rotor shape of the second modification. FIG. 14 is a view for explaining the rotor shape of the third modification. FIG. 15 is a diagram for explaining the rotor shape of another modification. FIG. 16 is a cross-sectional view perpendicular to the axial direction showing a general rotor shape of an IPM motor. FIG. 17 is a diagram for explaining a general rotor shape of an IPM motor and a rotor shape according to a conventional example in which grooves are provided on the outer periphery.

  FIG. 1 is a view for explaining an embodiment of a permanent magnet type rotating electrical machine according to the present invention. What is represented in the figure is a configuration diagram of the rotor 1 and the stator 5 provided in the permanent magnet type rotating electrical machine (hereinafter also simply referred to as a rotating electrical machine) according to the present embodiment as seen from a cross section perpendicular to the axial direction. Part of the overall configuration.

  The rotating electrical machine according to the present embodiment includes an annular stator 5, a cylindrical rotor 1 disposed on the inner peripheral side of the stator 5, and a permanent magnet 3 embedded in a corresponding portion of the rotor 1. , Constituting an electric motor or a generator. This rotating electric machine is classified as a so-called IPM (Interior Permanent Magnet) type rotating electric machine because the permanent magnet 3 is embedded in the rotor 1.

  The stator 5 includes a ring-shaped stator core 8 (base), a plurality of stator teeth 2 (hereinafter simply referred to as teeth 2) provided so as to protrude radially inward (rotation center side) from the stator core 8, and teeth 2 And a stator winding (not shown) wound by concentrated winding. The stator core 8 is formed by laminating electromagnetic steel plates that are soft magnetic materials, for example.

  The rotor 1 is concentric with the stator 5 and is disposed so as to have an air gap 6 (hereinafter simply referred to as a gap 6) between the front end surface of the teeth 2 formed on the stator 5. The rotor 1 has a rotor core 7. The rotor core 7 is formed in a cylindrical shape by a so-called laminated steel plate structure formed by laminating a number of electromagnetic steel plates formed by punching a metal plate having a high magnetic permeability into an annular shape in the axial direction. . Further, on the outer peripheral side of the rotor 1 facing the stator 5, the magnetic poles constituted by the permanent magnets 3 are equidistant from each other along the circumferential direction, and the polarities of the adjacent magnetic poles are different from each other. Is provided.

  The permanent magnet 3 forms one magnetic pole on the rotor 1. The rotor 1 according to the rotating electrical machine of the present embodiment has a 20-pole structure in which 20 permanent magnets 3 are provided along the circumferential direction. The direction of the magnetic flux produced by one permanent magnet 3 constituting one magnetic pole is the d-axis, and the direction perpendicular to the d-axis electrically and magnetically is the q-axis.

  Here, a 20-pole rotor is taken as an example, but the number of poles is not limited to this. However, the number of teeth 2 that the stator 5 has is premised on the ratio of the number of poles of the rotor being 2: 3. Since the rotor 1 according to this embodiment has a 20-pole structure, the number of teeth 2 is 30.

  Moreover, the rotor 1 has the flux barrier 4 as a space part between each magnetic pole. The flux barrier 4 is formed by punching a magnetic steel sheet that forms the rotor core 7. Further, the flux barrier 4 has a lower magnetic permeability than the magnetic steel sheet, that is, has a large magnetic resistance. Therefore, the flux barrier 4 acts as a magnetic barrier in which the magnetic flux (flux) is difficult to pass in the magnetic circuit formed by the permanent magnet 3 on the rotor 1.

  The rotor 1 has a first groove G1 formed on the outer peripheral surface located on the q-axis so as to be recessed from the outer peripheral surface toward the rotation center side along the axial direction of the rotor 1, and the first groove G1. A second groove G2 that is provided on the outer peripheral surface on the d-axis side continuously with the first groove G1, and that is recessed from the outer peripheral surface toward the rotation center side along the axial direction of the rotor 1. Have The present invention is characterized by the first groove G1 and the second groove G2 provided in the rotor 1 and the shape of the tooth 2 determined based on the relative positional relationship between the rotor 1 provided with these grooves on the outer periphery. Have

  Here, before explaining the details of the shapes of the first and second grooves G1, G2 and the teeth 2 which are the features of the present embodiment, the conventional rotor shape and its problems that are compared with the present invention are compared. explain.

  FIG. 16 shows a general rotor shape of an IPM motor in which one permanent magnet is disposed per pole. An embedded magnet type motor having a structure in which a permanent magnet is embedded in a rotor core having a plurality of magnet insertion holes has a saliency in which the magnetic reluctance (reluctance) of the rotor changes depending on the rotation angle. The reluctance torque using the saliency can be effectively used, and the torque density output from the motor can be improved. Therefore, the IPM motor is widely used as a drive source for an electric vehicle and a motor for generating electricity (rotary electric machine).

  However, on the other hand, since the generated torque changes depending on the rotation angle of the rotor, torque pulsation (torque ripple) accompanying rotation of the rotor is generated, which is a main factor of vibration and noise of the rotating electrical machine. Further, since magnetic flux from the permanent magnet exists even when there is no energization, torque pulsation occurs due to the relative positional relationship between the rotor and the stator teeth, and this is called cogging torque. The cogging torque is also a factor of vibration and noise of the rotating electrical machine when no power is supplied. In particular, when a rotating electrical machine having such characteristics is applied to an electric vehicle as a vehicle drive motor, both torque ripple and cogging torque cause vehicle sound vibration deterioration, and it is therefore required to reduce them as much as possible. .

  In contrast, in Japanese Patent Laid-Open No. 2012-16189 (see Patent Document 1, especially FIG. 2), as described above, a groove that is recessed from the outer peripheral surface to the rotation center side is provided between the magnetic poles configured in the rotor. A rotor is disclosed that can reduce cogging torque or torque ripple by forming one magnetic pole sandwiched between the two magnetic poles so as to have a convex shape with a predetermined width in the outer circumferential direction.

  FIG. 17 is a diagram for explaining a general rotor shape (a) of an IPM motor and a rotor shape (b) according to a conventional example in which grooves are provided on the outer periphery. Here, when designing the shape of the rotor, from the viewpoint of anti-centrifugal strength, the outer peripheral side of the permanent magnet embedded in the rotor, particularly the circumferential end of the permanent magnet where stress due to centrifugal force is concentrated. It is necessary to ensure a rotor core width that can withstand the stress on the outer peripheral side. W shown in FIG. 17A indicates the rotor core width (hereinafter referred to as the core width W). As shown in FIG. 17A, the rectangular (I-type) permanent magnet embedded along the outer periphery of the annular rotor secures the core width W at a position facing the circumferential end of the permanent magnet. Thus, the embedding depth L of the permanent magnet on the d axis is determined. Based on this premise, the rotor shape according to the conventional example shown in FIG.

  The rotor shape according to the conventional example is characterized in that a groove is provided between the magnetic poles formed on the rotor, that is, on the q axis. Then, as shown in FIG. 17B, when the core width W is secured at a position facing the circumferential end of the permanent magnet, the groove is formed so that the permanent magnet needs to be arranged closer to the center of rotation. Therefore, the embedding depth is 1.3L. As a result, in the conventional example in which the groove is provided, the permanent magnet is deeply buried on the inner peripheral side compared to a general rotor shape in which no groove is formed, so that the magnetic flux interlinked with the stator is reduced. As a result, the generated torque decreases.

  The present invention can suppress a torque drop and reduce torque ripple or cogging torque while forming a groove recessed from the outer peripheral surface toward the rotation center side on the q axis in the outer periphery of the rotor 1. The purpose is to provide technology that can be used. Hereinafter, the details of the permanent magnet type rotating electrical machine according to an embodiment of the present invention will be described.

  Returning to FIG. 1, the description will be continued. As described above, the rotor 1 according to the present embodiment is formed on the outer peripheral surface located on the q axis so as to be recessed from the outer peripheral surface toward the rotation center side along the axial direction of the rotor 1. The groove G1 is provided on the outer peripheral surface on the d-axis side of the first groove G1 so as to be continuous with the first groove G1, and is recessed from the outer peripheral surface toward the rotation center side along the axial direction of the rotor 1. And the formed second groove G2. The first groove G1 and the second groove G2 are such that the outer peripheral surface of the rotor 1 is a tooth between the first groove G1 and the second groove G2 provided continuously with the first groove G1. 2, in other words, the portion having the largest radial width of the rotor 1 (hereinafter referred to as the connecting portion 9) between the first groove G <b> 1 and the second groove G <b> 2 is permanent. It is formed so as to be in a position facing the circumferential end of the magnet 3. As described above, the rotor 1 is formed with the first groove G1 and the second groove G2 on the left and right sides of the outer peripheral position facing the circumferential end of the permanent magnet 3.

  FIG. 2 is a diagram for explaining indices used to define the shapes of the first groove G1, the second groove G2, and the connecting portion 9. In FIG. The dotted line in the figure is the virtual outer periphery C of the rotor 1. This virtual outer periphery C is represented by a perfect circle that passes through the outermost peripheral portion (point A in the figure) on the d-axis of the rotor 1 with respect to the rotation center of the rotor 1, and includes the first groove G1 and the second groove G2 is a reference for defining the shape of the connecting portion 9. The virtual outer periphery C is a line that matches the outer diameter line of the rotor core 7 when no groove is formed.

  The depth of the first groove G1 is defined as d1. d1 indicates the length from the virtual outer periphery C to the deepest part (the part closest to the rotation center) of the first groove G1.

  The depth of the second groove G2 is defined as d2. d2 indicates the length from the virtual outer periphery C to the deepest part of the second groove G2.

  The depth of the connecting portion 9 is defined as d3. d3 indicates the length from the virtual outer periphery C to the portion closest to the tip surface of the tooth 2 at the connecting portion 9. d3 is set in consideration of the strength against centrifugal force.

  When the first groove G1, the second groove G2, and the connecting portion 9 are defined in this way, the shape of the rotor 1 in the present embodiment is formed so as to satisfy the following. That is, the first groove G1 is formed to satisfy d1 ≧ d3. The second groove G2 is formed to satisfy d2 ≧ d3.

  3 shows a general rotor shape (a) of the IPM motor shown in FIG. 17, a rotor shape (b) according to a conventional example in which grooves are provided on the outer periphery, and a shape (c) of the rotor 1 of the present embodiment. FIG.

  As shown in FIG. 3C, the groove that was one in the conventional example is divided into two, the first groove G1 and the second groove G2, through the connecting portion 9 in the present embodiment. Form. The first groove G <b> 1 and the second groove G <b> 2 are formed such that the connecting portion 9 is located at a position facing the circumferential end of the permanent magnet 3 in the rotor 1. Then, from the viewpoint of anti-centrifugal strength, it is only necessary to secure the core width W at the connecting portion 9, so that the permanent magnet 3 is fixed while keeping the core width W shown in FIGS. 3 (a) and 3 (b) constant. Since it can arrange | position on the outer peripheral side compared with a prior art example, the embedding depth of this permanent magnet 3 can be made small. In addition, since the depth d3 of the connecting portion 9 may be 0, the embedding depth of the permanent magnet 3 of the present embodiment can be made smaller than 1.1 L shown in FIG. There is (for example, 1.0 L).

  FIG. 4 is a diagram for comparing the maximum torque of each of the three rotor shapes including the present embodiment shown in FIG. 3. The maximum torque according to each rotor shape is represented by a ratio [%] where the maximum torque according to the groove-free shape (FIG. 3A) is 100%. As can be seen from the analysis results shown in FIG. 4, according to the rotor shape of the present embodiment, the torque can be increased by about 1.2% compared to the conventional example.

  Next, on the premise of the shape of the rotor 1 described so far, the details of the shape of the rotor 1 are defined while referring to the relationship with the shape of the tooth 2 according to the present embodiment. Specifically, from the viewpoint of the effect of reducing torque ripple, on the outer peripheral surface of the rotor 1, the width between the end portions on the d-axis side of the second groove G2 adjacent to the d-axis (projection portion width θ1) is appropriate. Stipulate the size.

  FIG. 5 is a diagram for explaining the convex portion width θ1 and the width θ2 of the tip portion of the tooth 2. FIG. θ1 represents, in electrical angle, the width between the d-axis side ends of the second grooves G2 adjacent to each other across the d-axis on the outer periphery of the rotor 1. θ2 represents the circumferential width (tip width) of the tip portion on the rotation center side of the tooth 2 in electrical angle.

  FIG. 6 is a diagram showing a torque ripple analysis value when the convex portion width θ1 of the rotor 1 and the tip width θ2 of the tooth 2 are changed under load (when energized). The horizontal axis indicates the convex portion width θ1 [°] of the rotor 1, and the vertical axis indicates the tip width θ2 [°] of the tooth 2. Each area ag divided by the contour line shown in the figure is divided by the size of the torque ripple, the torque ripple in the area indicated by a is the smallest, and the torque ripple in the area indicated by g is the largest.

  From the analysis result of FIG. 6, it can be seen that the torque ripple can be reduced as the convex portion width θ <b> 1 is reduced regardless of the size of the tip width θ <b> 2 of the tooth 2. From this analysis result, the second groove G2 in the present embodiment is formed so that the convex portion width θ1 of the rotor 1 satisfies θ1 <75 °. By defining the size of the convex portion width θ1 of the rotor 1 in this way, it is possible to reduce torque ripple without accompanying torque reduction.

  Next, from the viewpoint of the cogging torque reduction effect, the convex portion width θ1 [°] of the rotor 1 and the tip width θ2 [°] of the tooth 2 are defined. As a premise thereof, there is a correlation as shown in FIG. 7 between the tip width θ2 of the tooth 2 and the cogging torque.

  FIG. 7 is a diagram showing the relationship between the tip width θ2 of the tooth 2 and the cogging torque. The horizontal axis represents the tip width θ2 [°] of the tooth 2, and the vertical axis represents the magnitude of the cogging torque amplitude (peak to peak). As can be seen from the analysis result of FIG. 7, the cogging torque varies greatly depending on the size of the tip width θ <b> 2 of the tooth 2, and becomes the smallest at θ <b> 2 = 92 °. Based on this analysis result, an appropriate electrical angular width [°] of the convex portion width θ1 of the rotor 1 and the tip width θ2 of the tooth 2 is defined from the viewpoint of the effect of reducing the cogging torque.

  FIG. 8 is a diagram showing the cogging torque analysis value when the convex portion width θ1 of the rotor 1 and the tip width θ2 of the tooth 2 are changed in no load (non-energized state). The horizontal axis indicates the convex portion width θ1 [°] of the rotor 1, and the vertical axis indicates the tip width θ2 [°] of the tooth 2. Each area a to h divided by the contour lines shown in the figure is partitioned by the magnitude of the cogging torque, the cogging torque in the area indicated by a is the smallest, and the cogging torque in the area indicated by h is the largest.

  From the analysis result of FIG. 8, it can be seen that the magnitude of the cogging torque has a correlation with both the convex portion width θ1 and the tip width θ2. That is, when designing the optimum shape of the rotor 1 from the viewpoint of the cogging torque reduction effect, not only the convex portion width θ1 but also both the convex portion width θ1 of the rotor 1 and the tip width θ2 of the teeth 2 are considered. There is a need.

  Therefore, the convex portion width θ1 and the tip width θ2 according to the present embodiment are defined within a range showing a relatively high cogging torque reduction effect derived from the analysis result of FIG. That is, the convex portion width θ1 is formed so as to satisfy θ1> 52 °, and the tip width θ2 is formed so as to satisfy 87 ° <θ2 <98 °. Thereby, in the rotary electric machine comprised with the rotor 1 and the stator 5, the reduction effect of cogging torque can be acquired reliably.

  Furthermore, in consideration of the effect of reducing torque ripple based on the convex portion width θ1 of the rotor 1 shown in FIG. 6, the convex portion width θ1 is formed so as to satisfy 52 ° <θ1 <75 °. In the permanent magnet type rotating electrical machine according to the embodiment, both the torque ripple and the cogging torque can be reliably reduced. The prescribed range is based on the thick frame in FIG.

  Next, the shape of the tip of the tooth 2 that is characteristic of the present invention will be described. The tooth 2 according to the present embodiment has notches 10 at both ends in the circumferential direction of the tip portion of the tooth 2.

  FIG. 9 is a view for explaining the shape of the notch 10. As shown in the drawing, the notches 10 are formed at both ends in the circumferential direction of the distal end portion of the tooth 2 so as to scrape the distal end portion of the tooth 2 from the circumferential center side toward the circumferential end portion. And the optimal circumferential direction length of each notch 10 formed in the both ends of the front-end | tip part of the teeth 2 can be prescribed | regulated from a viewpoint of the reduction effect of cogging torque.

  Below, the circumferential direction length of the notch 10 is prescribed | regulated by the electrical angular width (tooth convex part width | variety (theta) 3) between the edge parts of the circumferential direction center side of the tooth 2 of the notch 10, as shown in FIG.

  FIG. 10 is a diagram showing the cogging torque analysis value when the tooth convex portion width θ3 is changed at the time of no load (non-energization). The horizontal axis indicates the tooth convex width θ3 [°], and the vertical axis indicates the amplitude of the cogging torque. A dotted line drawn horizontally in the center of the figure indicates a point where the teeth tip width θ2 and the teeth convex portion width θ3 coincide, that is, the magnitude of the cogging torque when the notch 10 is not formed. From the analysis result of FIG. 10, it can be seen that the cogging torque varies greatly depending on the size of the teeth convex portion width θ3. And it turns out that the cogging torque reduction effect can be acquired by forming the notch 10 so that the teeth convex part width | variety (theta) 3 may become larger than an electrical angle of 46 degrees. It should be noted that the highest cogging torque reduction effect can be obtained with the teeth convex portion width θ3 = 61 °.

  Therefore, the notches 10 are formed at both ends of the tip of the tooth 2 in the present embodiment so as to satisfy the teeth convex portion width θ3> 46 °. Thereby, the cogging torque can be further reduced in the relative positional relationship with the rotor 1 as compared with the case where the notch 10 is not formed in the tooth 2.

  Next, the depth d2 of the second groove G2 formed in the rotor 1 of the present embodiment is defined from the relationship with the gap width dg of the gap 6 provided between the rotor 1 and the stator 5. The gap width dg is the distance from the tip surface of the tooth 2 to the virtual outer periphery C of the rotor 1 as shown in FIG.

  FIG. 11 shows the cogging torque (no load) and torque ripple (with load) when the gap width dg is constant and the depth d2 of the second groove G2 is changed at no load and at load. It is a figure which shows an analysis value. The horizontal axis indicates the ratio of the depth d2 of the second groove G2 to the gap width dg, and the vertical axis indicates the magnitude of the amplitude of the torque ripple and the cogging torque, d2 = 0, that is, when the second groove G2 is not formed. Is shown as a ratio with 100%.

  From the analysis result of FIG. 11, d2 / dg> 0.4, that is, the depth d2 of the second groove G2 is set to 40% or more of the gap width dg, compared with the case where the second groove G2 is not formed. It can be seen that the cogging torque can be greatly reduced. Further, it can be seen that by satisfying d2 / dg> 0.4, the torque ripple at the time of load can be reduced by at least 20% or more.

  Therefore, the depth d2 of the second groove G2 in the present embodiment is formed so as to satisfy d2 / dg> 0.4. As a result, the cogging torque and the torque ripple can be greatly reduced as compared with the rotor shape not provided with the second groove G2.

  As described above, the permanent magnet type rotating electrical machine according to the embodiment includes a plurality of stators 5 each having a plurality of teeth 2 formed to project radially inward from an annular base (stator core 8), and a plurality of magnetic poles formed by the permanent magnets 3. And a rotor 1 having the same. The rotor 1 has a first groove G1 formed along the axial direction of the rotor 1 on the outer circumference on the q axis that is electrically orthogonal to the d axis that is formed by one magnetic pole, and is more d than the first groove G1. On the outer periphery on the shaft side, the second groove G2 is provided continuously with the first groove G1 and formed along the axial direction of the rotor 1. The true circle passing through the outermost peripheral part on the d-axis of the rotor 1 with respect to the rotation center of the rotor 1 is defined as the virtual outer periphery C of the rotor 1, and the depth from the virtual outer periphery C of the deepest part in the first groove G1. D1 and the depth from the virtual outer periphery C of the deepest part in the second groove G2 is d2, and the portion closest to the tip surface of the tooth 2 between the first groove G1 and the second groove G2 ( The first groove G1 is formed so as to satisfy d1 ≧ d3 and the second groove G2 satisfies d2 ≧ d3, where d3 is the depth from the virtual outer periphery C in the connecting portion 9). It is formed. Thereby, the embedding depth of the permanent magnet 3 can be reduced while securing the core width W necessary from the viewpoint of anti-centrifugal strength, and the torque can be increased as compared with the conventional example.

  Further, according to the permanent magnet type rotating electrical machine according to the embodiment, when the width between the d-axis side ends of the second grooves G2 adjacent to each other with the d-axis interposed therebetween is set to θ1 in electrical angle, the second The groove G2 is formed so as to satisfy θ1 <75 °. Thereby, a torque ripple can be reduced irrespective of the front-end | tip part width | variety of the teeth 2. FIG.

  Further, according to the permanent magnet type rotating electric machine according to the embodiment, the width between the d-axis side end portions of the second groove G2 adjacent to each other with the d-axis interposed therebetween is θ1 in electrical angle, and the tip end portion of the tooth 2 The second groove G2 is formed so as to satisfy θ1> 52 ° when the circumferential width at is an electrical angle θ2, and the tip of the tooth 2 satisfies 87 ° <θ2 <98 °. It is formed. By defining the protrusion width θ1 of the rotor 1 and the tip width θ2 of the teeth 2 in this way, the cogging torque can be reliably reduced without a decrease in torque.

  Moreover, according to the permanent magnet type rotating electrical machine according to the embodiment, the notch 10 formed from the circumferential center side of the tip of the tooth 2 toward the end is provided at both ends of the tip of the tooth 2 in the circumferential direction. When the width between the end portions of the notch 10 on the center side in the circumferential direction at the tip end of the tooth 2 is θ3 in electrical angle, the notch 10 satisfies θ3> 46 °. It is formed. Thereby, the cogging torque can be further reduced.

  Further, according to the permanent magnet type rotating electrical machine according to the embodiment, when the gap width between the tip surface of the tooth 2 and the outer periphery of the rotor 1 on the d axis is dg, the second groove G2 is , D2 / dg> 0.4. As a result, the cogging torque at the time of no load can be greatly reduced, and the torque ripple at the time of load can be reduced.

  Below, the modification provided with the characteristic which concerns on one Embodiment demonstrated until now is shown with reference to FIGS.

-Modification 1-
FIG. 12 is a diagram for explaining the rotor shape of the first modification. In the first modification, the second groove G2 is composed of a plurality of grooves. When the second groove G2 is constituted by a plurality of grooves, the end on the d-axis side of the second groove G2 when defining the protrusion width θ1 of the rotor 1 is a point B in the figure. Thus, the 2nd groove | channel G2 concerning this invention is not restricted to one, You may be comprised by a 2 or more some groove | channel.

-Modification 2-
FIG. 13 is a view for explaining the rotor shape of the second modification. In the second modification, one magnetic pole is formed by arranging two permanent magnets 3 in an I shape. Thus, the single magnetic pole according to the present invention is not limited to being constituted by a single permanent magnet, but may be constituted by a plurality of permanent magnets.

-Modification 3-
FIG. 14 is a view for explaining the rotor shape of the third modification. In the third modification, the two permanent magnets are arranged in a substantially V shape so as to open to the outer peripheral side of the rotor 1. Thus, the arrangement of the permanent magnets according to the present invention does not necessarily have to be I-shaped, and may be V-shaped. When the permanent magnet 3 is arranged in a V shape, the connecting portion 9 between the first groove G1 and the second groove G2 forms one magnetic pole in the first groove G1 and the second groove G2. The permanent magnet 3 is formed so as to be opposed to the outermost peripheral portion at the circumferential end. As shown in FIG. 15, another permanent magnet 3 is further arranged on the outer peripheral side of the two permanent magnets arranged in a V shape, and three permanent magnets arranged in a substantially triangular shape. One magnetic pole may be constituted by a magnet.

  The present invention is not limited to the above-described embodiment and modifications, and further modifications and applications are possible.

DESCRIPTION OF SYMBOLS 1 ... Rotor 2 ... Teeth 3 ... Permanent magnet 5 ... Stator 6 ... Gap 8 ... Base (stator core)

Claims (6)

In a permanent magnet type rotating electrical machine comprising: a stator having a plurality of teeth formed projecting radially inward from an annular base; and a rotor having a plurality of magnetic poles formed of at least one permanent magnet.
The rotor has a first groove formed on an outer periphery on a q-axis that is electrically orthogonal to a d-axis formed by the one magnetic pole, along the axial direction of the rotor, and d more than the first groove. A second groove formed continuously along the axial direction of the rotor, provided continuously to the first groove on the outer periphery on the shaft side,
A permanent magnet type rotating electrical machine. The rotor is disposed via a gap having a predetermined width between the outer periphery of the rotor and the tip surface of the teeth.
With respect to the rotation center of the rotor, a perfect circle that passes through the outermost peripheral part on the d-axis of the rotor is a virtual outer periphery of the rotor,
The depth from the virtual outer periphery of the deepest part in the first groove part is d1,
The depth from the virtual outer periphery of the deepest part in the second groove part is d2,
Between the first groove portion and the second groove portion, when the depth from the virtual outer periphery in the portion closest to the tip surface is d3,
The first groove is formed to satisfy d1 ≧ d3,
The second groove is formed to satisfy d2 ≧ d3.
The permanent magnet type rotating electrical machine according to claim 1. When the width between the end portions on the d-axis side of the second groove portions adjacent to each other across the d-axis is θ1 in electrical angle,
The second groove is formed to satisfy θ1 <75 °.
The permanent magnet type rotating electrical machine according to claim 1 or 2. The width between the end portions on the d-axis side of the second groove portions adjacent to each other across the d-axis is θ1 in electrical angle,
When the circumferential width at the tip of the teeth is θ2 in electrical angle,
The second groove is formed to satisfy θ1> 52 °,
The tip of the teeth is formed to satisfy 87 ° <θ2 <98 °.
The permanent magnet type rotating electrical machine according to any one of claims 1 to 3, wherein The teeth have notches formed at both ends in the circumferential direction of the tip portion of the teeth from the circumferential center side of the teeth tip toward the end portion,
In the tip portion of the teeth, when the width between the ends of the notches in the circumferential center side of the tip portion of the teeth is θ3 in electrical angle,
The notch is formed to satisfy θ3> 46 °.
The permanent magnet type rotating electrical machine according to any one of claims 1 to 4, wherein When the gap width between the tip surface of the teeth and the outer periphery of the rotor on the d-axis is dg,
The second groove is formed to satisfy d2 / dg> 0.4.
The permanent magnet type rotating electrical machine according to any one of claims 2 to 5, wherein

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