JP6507956B2 - Permanent magnet type rotating electric machine - Google Patents

Description

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

  Conventionally, in a rotor having a plurality of magnetic poles, a groove is provided 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. Patent Document 1 discloses a rotor capable of reducing cogging torque or torque ripple.

JP, 2012-16189, A

  By the way, in the structural design of the rotor, it is necessary to secure a rotor core width that can withstand the centrifugal force on the outer peripheral side of the permanent magnet embedded in the rotor from the viewpoint of the centrifugal strength. Therefore, in the rotor disclosed in Patent Document 1, since the permanent magnet needs to be disposed on the inner peripheral side by providing the groove, the magnet magnetic flux linked to the stator weakens, and the torque decreases. I will.

  Further, the technology disclosed in Patent Document 1 does not mention the shape of stator teeth for the above-described rotor. However, depending on the shape of the stator teeth, it may not be possible to sufficiently obtain the cogging torque reduction effect by providing the groove in the rotor.

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

The permanent magnet type rotating electric machine according to the present invention includes a stator having a plurality of teeth formed by projecting radially inward from an annular base, and a rotor having a plurality of magnetic poles formed by at least one permanent magnet. The rotor is disposed with a gap of a predetermined width between the outer periphery of the rotor and the tip end face of the teeth. The rotor has a first groove formed along the axial direction of the rotor on the outer periphery on the q axis which is electrically orthogonal to the d axis formed by one magnetic pole , and the d axis more than the first groove. The second groove formed along the axial direction of the rotor is provided continuously with the first groove on the outer periphery on the side, and a connecting portion provided between the first groove and the second groove And . The connecting portion is a predetermined circle which is larger than 0 from a virtual outer periphery in a portion closest to the tip end surface, when a true circle passing through the outermost periphery on the d-axis of the rotor with respect to the rotational center of the rotor It is formed to have a depth of.

  According to the present invention, in addition to the first groove provided on the q-axis, a second groove provided continuously to the first groove is formed on the outer periphery on the d-axis side of the first groove. As a result, it is possible to secure the rotor core width satisfying the centrifugal strength at the connecting portion between the first groove portion and the second groove portion and to arrange the permanent magnet more on the rotor outer peripheral side. Cogging torque or torque ripple can be reduced without any reduction.

FIG. 1 is a view for explaining an embodiment of a permanent magnet type rotary electric machine according to the present invention. FIG. 2 is a view 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 for comparing a general rotor shape of an IPM motor and a rotor shape according to a conventional example in which a groove is provided on the outer periphery, and a rotor shape of 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 diagram for explaining the convex portion width θ1 of the rotor and the width θ2 of the tip portion of the teeth. FIG. 6 is a diagram showing torque ripple analysis values when the convex portion width θ1 of the rotor and the tip end width θ2 of the teeth are respectively changed at the time of loading. FIG. 7 is a diagram showing the relationship between the tip width θ2 of teeth and the cogging torque. FIG. 8 is a diagram showing cogging torque analysis values when the convex portion width θ1 of the rotor and the tip end width θ2 of the teeth are respectively changed at no load. Drawing 9 is a figure for explaining the shape of the notch formed in the teeth of one embodiment. FIG. 10 is a graph showing cogging torque analysis values 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 fixed and the depth d2 of the second groove is changed at no load and at load. FIG. 12 is a view for explaining a rotor shape of the first modification. FIG. 13 is a view for explaining a rotor shape of the second modification. FIG. 14 is a diagram for explaining a rotor shape of the third modification. FIG. 15 is a view for explaining a rotor shape of another modification. FIG. 16 is a cross-sectional view perpendicular to the axial direction showing a general rotor shape of the IPM motor. FIG. 17 is a view for explaining a general rotor shape of an IPM motor and a rotor shape according to a conventional example in which a groove is provided on the outer periphery.

  FIG. 1 is a view for explaining an embodiment of a permanent magnet type rotary electric machine according to the present invention. What is represented in the drawings is a configuration diagram of the rotor 1 and the stator 5 provided in the permanent magnet type rotating electric machine (hereinafter, also simply referred to as a rotating electric machine) according to the present embodiment as viewed from a cross section perpendicular to the axial direction It is part of the whole configuration.

  The rotating electrical machine according to the present embodiment includes a ring-shaped 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. , Motor or generator. The rotary electric machine is classified as a so-called IPM (Interior Permanent Magnet) type rotary 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 protruding from the stator core 8 radially inward (rotation center side), and teeth 2 And a stator winding (not shown) wound by concentrated winding. The stator core 8 is formed, for example, by laminating electromagnetic steel sheets, which are soft magnetic materials.

  The rotor 1 is concentric with the stator 5 and disposed so as to have an air gap 6 (hereinafter, simply referred to as a gap 6) with the tip 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 configured by axially laminating a large number of electromagnetic steel plates formed by punching a steel plate having a high magnetic permeability in an annular shape. . Further, on the outer peripheral side of the rotor 1 facing the stator 5, the magnetic poles formed by the permanent magnets 3 are equally spaced from each other along the circumferential direction, and the polarities of adjacent magnetic poles are different. Provided in

  One permanent magnet 3 constitutes one magnetic pole on the rotor 1. The rotor 1 which concerns on the rotary electric machine of this embodiment has 20 pole structure in which 20 pieces of permanent magnets 3 were 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 electrically perpendicular to the d-axis is the q-axis.

  Although a rotor having a 20-pole structure is taken as an example here, the number of poles is not limited to this. However, it is assumed that the number of teeth 2 included in the stator 5 has a ratio of 2: 3 with the number of poles of the rotor. Since the rotor 1 according to the present embodiment has a 20-pole structure, the number of teeth 2 is 30.

  The rotor 1 also has a flux barrier 4 as a space between the magnetic poles. The flux barrier 4 is formed by punching an electromagnetic steel plate forming the rotor core 7. Further, the flux barrier 4 has lower permeability than the electromagnetic steel plate, that is, larger magnetic resistance. Therefore, the flux barrier 4 acts as a magnetic barrier to which the magnetic flux (flux) is difficult to pass in the magnetic circuit in which the permanent magnet 3 is configured on the rotor 1.

  The rotor 1 has a first groove G1 formed on the outer peripheral surface located on the q axis along the axial direction of the rotor 1 so as to be recessed from the outer peripheral surface toward the rotation center, and a first groove G1. The second groove G2 is provided on the outer peripheral surface closer to the d-axis than the first groove G1 and is formed along the axial direction of the rotor 1 so as to be recessed from the outer peripheral surface toward the rotation center. 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 teeth 2 determined based on the relative positional relationship between the groove 1 and the rotor 1 provided on the outer periphery Have.

  Here, before describing the details of the shapes of the first and second grooves G1 and G2 and the teeth 2 which are the features of the present embodiment, the conventional rotor shape to be compared with the present invention and the problems thereof will be described. explain.

  FIG. 16 shows a general rotor configuration of an IPM motor in which one permanent magnet is disposed per one pole. An embedded magnet motor having a structure in which permanent magnets are embedded in a rotor core provided with a plurality of magnet insertion holes has saliency in which the reluctance (reluctance) of the rotor changes with the rotation angle, and therefore not only magnet torque The reluctance torque using the saliency can also be effectively utilized, and the torque density output by the motor can be improved. Therefore, the IPM motor is widely used as a drive source of an electric vehicle and a motor (a rotating electric machine) for power generation.

  However, on the other hand, since the generated torque changes according to the rotation angle of the rotor, torque pulsation (torque ripple) accompanying the rotation of the rotor is generated, which is a main cause of vibration and noise of the rotating electrical machine. In addition, since magnet magnetic flux from the permanent magnet is present even when no current is supplied, the relative positional relationship between the rotor and the stator teeth generates torque pulsation, which is called cogging torque. The cogging torque also causes vibration and noise of the rotating electrical machine at the time of non-energization. In particular, in the case where 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 deterioration of vehicle vibration, so it is required to reduce these as much as possible. .

  On the other hand, in Japanese Patent Application Laid-Open No. 2012-16189 (Patent Document 1, particularly, refer to FIG. 2), as described above, between the magnetic poles formed in the rotor, a groove recessed from the outer peripheral surface toward the rotation center is provided. A rotor is disclosed in which cogging torque or torque ripple can be reduced by forming one magnetic pole sandwiched between the two in a convex shape having a predetermined width in the outer peripheral direction.

  FIG. 17 is a view for explaining a general rotor shape (a) of an IPM motor and a rotor shape (b) according to a conventional example in which a groove is provided on the outer periphery. Here, when designing the shape of the rotor, from the viewpoint of the resistance to centrifugal force, the outer peripheral side of the permanent magnet embedded in the rotor, in particular, the circumferential direction end portion of the permanent magnet where the stress accompanying the centrifugal force is concentrated. It is necessary to secure on the outer peripheral side a rotor core width that can withstand the stress. W shown in FIG. 17A indicates the width of the rotor core (hereinafter referred to as the core width W). As shown in FIG. 17A, a rectangular (I-shaped) 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 embedded depth L of the permanent magnet on the d axis is determined. On the premise of this, the rotor shape according to the conventional example shown in FIG. 17 (b) will be described.

  The rotor shape according to the conventional example is characterized in that a groove is provided between 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, it is necessary to arrange the permanent magnet closer to the center of rotation because the groove is formed. Therefore, the embedding depth is 1.3 L. Then, in the conventional example in which the groove is provided, the permanent magnet is deeply buried on the inner peripheral side more than the general rotor shape in which the groove is not formed, so the magnet magnetic flux interlinking with the stator is reduced. And the generated torque is reduced.

  According to the present invention, it is possible to suppress a decrease in torque and reduce torque ripple or cogging torque while forming a groove recessed from the outer peripheral surface toward the rotation center on the q axis on the outer periphery of the rotor 1 It aims to provide technology that can Hereinafter, the details of the permanent magnet type rotary electric machine according to the 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 along the axial direction of the rotor 1 The groove G1 and an outer peripheral surface on the d-axis side of the first groove G1 are provided continuously with the first groove G1 so as to be recessed from the outer peripheral surface toward the rotation center along the axial direction of the rotor 1 And a formed second groove G2. The first groove G1 and the second groove G2 have teeth on the outer peripheral surface of the rotor 1 between the first groove G1 and the second groove G2 provided continuously with the first groove G1. The portion closest to the front end surface of 2 (in other words, the portion with the largest radial width of the rotor 1 between the first groove G1 and the second groove G2) (hereinafter referred to as the connecting portion 9) is permanent It is formed so as to be opposed to the circumferential end of the magnet 3. As described above, in the rotor 1, the first groove G 1 and the second groove G 2 are formed on the left and right sides of the outer peripheral position facing the circumferential end of the permanent magnet 3.

  FIG. 2 is a view for explaining an index used to define the shapes of the first groove G1, the second groove G2, and the connecting portion 9. As shown in FIG. The dotted line in the figure is a virtual outer circumference C of the rotor 1. The virtual outer periphery C is represented by a perfect circle passing through the outermost periphery (point A in the figure) on the d-axis of the rotor 1 with respect to the rotation center of the rotor 1, and the first groove G1, the second groove It becomes a standard for defining G2 and the shape of connecting part 9. The virtual outer circumference 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 represents the length from the virtual outer circumference C to the deepest portion (portion closest to the rotation center) of the first groove G1.

  The depth of the second groove G2 is defined as d2. d2 represents the length from the virtual outer circumference C to the deepest portion of the second groove G2.

  The depth of the connecting part 9 is defined as d3. d3 represents the length from the virtual outer circumference C to a portion closest to the tip surface of the tooth 2 in the connecting portion 9; d3 is set in consideration of the anti-centrifuge strength.

  When the first groove G1, the second groove G2, and the connecting portion 9 are thus defined, the shape of the rotor 1 in the present embodiment is formed to satisfy the following. That is, the first groove G1 is formed to satisfy d1 d d3. The second groove G2 is formed to satisfy d2 2 d3.

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

  As shown in FIG. 3C, the groove which is one in the conventional example is divided into two, the first groove G1 and the second groove G2 through the connecting portion 9 in this embodiment. Form. The first groove G1 and the second groove G2 are formed such that the connecting portion 9 is at a position where the rotor 1 faces the circumferential end of the permanent magnet 3. Then, from the viewpoint of the resistance to centrifugal force, it is sufficient to secure the core width W at the connecting portion 9, so the permanent magnet 3 can be maintained while securing the core width W shown in FIGS. Since it can arrange | position more on the outer peripheral side compared with a prior art example, 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. 3C. (Eg, 1.0 L).

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

  Next, on the premise of the shape of the rotor 1 described above, more details of the shape of the rotor 1 will be defined while referring to the relationship with the shape of the teeth 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, an appropriate width (convex portion width θ1) between the d-axis side end portions of the second grooves G2 adjacent to each other across the d-axis Define the size.

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

  FIG. 6 is a diagram showing torque ripple analysis values when the convex portion width θ1 of the rotor 1 and the tip width θ2 of the teeth 2 are each changed at the time of loaded (during energization). The horizontal axis indicates the convex portion width θ1 [°] of the rotor 1 and the vertical axis indicates the tip width θ2 [°] of the teeth 2. The areas a to g divided by the contour lines shown in the figure are divided by the magnitude of torque ripple, and the torque ripple in the area shown by a is the smallest, and the torque ripple in the area shown by g is the largest.

  From the analysis result of FIG. 6, it can be understood that the torque ripple can be reduced as the convex portion width θ1 becomes smaller regardless of the size of the tip width θ2 of the tooth 2. From this analysis result, the second groove G2 in the present embodiment is formed such 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 manner, it is possible to reduce the torque ripple without reducing the torque.

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

  FIG. 7 is a diagram showing the relationship between the tip width θ2 of the teeth 2 and the cogging torque. The horizontal axis indicates the tip width θ2 [°] of the tooth 2, and the vertical axis indicates the magnitude of the cogging torque amplitude (peak to peak). As can be seen from the analysis result of FIG. 7, the cogging torque largely changes depending on the size of the tip width θ2 of the tooth 2 and becomes the smallest at θ2 = 92 °. From the viewpoint of the reduction effect of the cogging torque, an appropriate electrical angle width [°] of the convex portion width θ1 of the rotor 1 and the tip width θ2 of the teeth 2 is defined on the premise of the analysis result.

  FIG. 8 is a diagram showing cogging torque analysis values when the convex portion width θ1 of the rotor 1 and the tip width θ2 of the teeth 2 are respectively changed at no load (during non-energization). The horizontal axis indicates the convex portion width θ1 [°] of the rotor 1 and the vertical axis indicates the tip width θ2 [°] of the teeth 2. The areas a to h divided by the contour lines shown in the figure are divided by the magnitude of the cogging torque, the cogging torque of the area shown by a is the smallest, and the cogging torque of the area shown by h is the largest.

  From the analysis result of FIG. 8, it can be understood that the magnitude of the cogging torque has a correlation with both of the protrusion width θ1 and the tip width θ2. That is, when designing the optimum shape of the rotor 1 from the viewpoint of the reduction effect of the cogging torque, not only the convex part width θ1 but also both the convex part 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 in 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 to satisfy θ1> 52 °, and the tip width θ2 is formed to satisfy 87 ° <θ2 <98 °. Thereby, in the rotary electric machine configured by the rotor 1 and the stator 5, the reduction effect of the cogging torque can be reliably obtained.

  Furthermore, in consideration of the torque ripple reduction effect based on the convex portion width θ1 of the rotor 1 shown in FIG. 6, the present embodiment is implemented by forming the convex portion width θ1 so as to satisfy 52 ° <θ1 <75 °. In the permanent magnet type rotary electric machine according to the embodiment, it is possible to reliably reduce both the torque ripple and the cogging torque. The specified range is based on the bold frame in FIG.

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

  FIG. 9 is a view for explaining the shape of the notch 10. As shown in the figure, the notches 10 are formed on both ends in the circumferential direction of the tip end of the tooth 2 so as to scrape the tip of the tooth 2 from the circumferential center side toward the circumferential end. Then, from the viewpoint of the reduction effect of the cogging torque, it is possible to define the optimal circumferential length of each notch 10 formed on both ends of the tip end portion of the tooth 2.

  Hereinafter, as shown in FIG. 9, the circumferential length of the notch 10 is defined by an electrical angle width (tooth convex portion width θ3) between the circumferential center side end of the tooth 2 of the notch 10.

  FIG. 10 is a diagram showing a cogging torque analysis value when the tooth convex portion width θ3 is changed at no load (during non-energization). The horizontal axis indicates the tooth convex portion width θ3 [°], and the vertical axis indicates the magnitude of the cogging torque amplitude. A dotted line drawn horizontally at almost the center of the figure shows a point where the tooth tip width θ2 and the tooth 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 is understood that the cogging torque largely changes depending on the size of the tooth convex portion width θ3. Then, it can be understood that the cogging torque reduction effect can be obtained by forming the notch 10 so that the tooth convex portion width θ3 is larger than the electrical angle 46 °. The highest cogging torque reduction effect can be obtained with the tooth convex portion width θ3 = 61 °.

  Therefore, the notches 10 are formed on both ends of the tip end portion of the tooth 2 in the present embodiment so as to satisfy the tooth convex portion width θ3> 46 °. Thus, the cogging torque can be further reduced in the relative positional relationship with the rotor 1 than in the case where the notches 10 are not formed in the teeth 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 a distance from the tip end face of the teeth 2 to the virtual outer circumference C of the rotor 1 as shown in FIG.

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

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

  Therefore, the depth d2 of the second groove G2 in the present embodiment is formed to satisfy d2 / dg> 0.4. This makes it possible to significantly reduce cogging torque and torque ripple as compared with the rotor shape in which the second groove G2 is not provided.

  As described above, the permanent magnet type rotating electric machine according to the embodiment includes the plurality of magnetic poles formed by the permanent magnet 3 and the stator 5 having the plurality of teeth 2 formed by projecting radially inward from the annular base (the stator core 8). And a rotor 1. The rotor 1 has a first groove G1 formed along the axial direction of the rotor 1 and an outer periphery on the q axis, which is electrically orthogonal to the d axis formed by one magnetic pole, and the first groove G1. A second groove G2 is provided on the outer periphery of the shaft side so as to be continuous with the first groove G1 and formed along the axial direction of the rotor 1. Then, a true circle passing through the outermost periphery on the d-axis of the rotor 1 with respect to the rotation center of the rotor 1 is taken as a virtual outer periphery C of the rotor 1, and the depth from the virtual outer periphery C of the deepest portion in the first groove Is d1, and the depth from the virtual outer periphery C of the deepest portion 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 to satisfy d1 ≧ d3 and the second groove G2 is to satisfy d2 ≧ d3 when the depth from the virtual outer periphery C in the connecting portion 9) is d3. It is formed. Thereby, the embedding depth of the permanent magnet 3 can be reduced while securing the necessary core width W from the viewpoint of the resistance to centrifugal force, and the torque can be increased as compared with the conventional example.

  Further, according to the permanent magnet type rotary electric machine according to one embodiment, when the width between the d-axis side end portions of the second grooves G2 adjacent to each other across the d-axis is θ1 in electrical angle, the second The groove G2 is formed to satisfy θ1 <75 °. Thereby, the torque ripple can be reduced regardless of the width of the tip end of the tooth 2.

  Further, according to the permanent magnet type rotating electrical machine according to one embodiment, the width between the d-axis side end portions of the second grooves G2 adjacent to each other across the d-axis is θ1 in electrical angle, The second groove G2 is formed so as to satisfy θ1> 52 °, and the tip portion of the tooth 2 is satisfied such that 87 ° <θ2 <98 °, where θ2 is the circumferential width at the electrical angle. It is formed. By defining the projection width θ1 of the rotor 1 and the tip width θ2 of the teeth 2 in this manner, the cogging torque can be reliably reduced without a decrease in the torque.

  Further, according to the permanent magnet type rotating electrical machine according to one embodiment, the notches 10 formed on both ends in the circumferential direction of the tip of the tooth 2 from the circumferential center side of the tip of the tooth 2 toward the end When the width between the ends on the circumferential center side of the tip of the tooth 2 at the tip 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 one embodiment, when the gap width between the tip end face of the teeth 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 no load can be significantly reduced, and the torque ripple at load can be reduced.

  Below, the modification provided with the feature concerning one embodiment explained until now is presented with reference to Drawings 12-15.

-Modification 1-
FIG. 12 is a view for explaining a rotor shape of the first modification. In the first modification, the second groove G2 is formed of a plurality of grooves. When the second groove G2 is formed of a plurality of grooves, the d-axis side end of the second groove G2 at the time of defining the protrusion width θ1 of the rotor 1 is a point B in the drawing. As described above, the second groove G2 according to the present invention is not limited to one, and may be configured by two or more grooves.

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

-Modification 3-
FIG. 14 is a diagram for explaining a rotor shape of the third modification. In the third modification, two permanent magnets are disposed in a substantially V-shape so as to open on the outer peripheral side of the rotor 1. As described above, the arrangement of the permanent magnet according to the present invention does not necessarily have to be I-shaped, and may be V-shaped. In the case where the permanent magnet 3 is arranged in a V-shape, in the first groove G1 and the second groove G2, the connecting portion 9 between the first groove G1 and the second groove G2 constitutes one magnetic pole. The permanent magnet 3 is formed so as to face the outermost peripheral portion of the circumferential end of the permanent magnet 3. As shown in FIG. 15, another permanent magnet 3 is disposed on the outer peripheral side of the two permanent magnets disposed in the V shape, and three permanent magnets disposed in a substantially triangular shape are provided. The magnet may constitute one magnetic pole.

  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 rotary electric machine comprising: a stator having a plurality of teeth formed by projecting radially inward from an annular base; and a rotor having a plurality of magnetic poles formed by at least one permanent magnet,
The rotor is disposed with a gap having a predetermined width between the outer periphery of the rotor and the tip end face of the teeth, and the outer periphery on the q-axis, which is electrically orthogonal to the d-axis formed by one magnetic pole,
A first groove formed along an axial direction of the rotor;
A second groove formed along the axial direction of the rotor and provided continuously on the outer periphery on the d-axis side of the first groove on the d-axis side;
A connecting portion provided between the first groove and the second groove;
When the connecting portion is a virtual circle passing through the outermost periphery on the d-axis of the rotor with respect to the rotational center of the rotor, the virtual outer periphery of the portion closest to the tip end surface Formed to have a predetermined depth greater than 0,
A permanent magnet type rotating electrical machine characterized by The depth from the virtual outer periphery of the deepest portion is d1 of the first groove prior to reporting,
Let the depth from the virtual outer periphery of the deepest portion in the second groove be d2.
When the predetermined depth of the connecting portion is d3:
The first groove portion is formed to satisfy d1 ≧ d3.
The second groove is formed to satisfy d22d3.
The permanent magnet type rotary electric machine according to claim 1, characterized in that When the width between the d-axis side end portions 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 rotary electric machine according to claim 1 or 2, characterized in that: The width between the d-axis side end portions of the second groove portions adjacent to each other across the d-axis is an electrical angle θ1.
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 tips of the teeth are formed to satisfy 87 ° <θ2 <98 °.
The permanent magnet type rotary electric machine according to any one of claims 1 to 3, characterized in that: The teeth have notches formed at circumferentially opposite ends of the tip end of the teeth from the circumferential center side of the tip of the teeth toward the end.
In the case where the width between the end portions on the circumferential center side of the tip end of the tooth at the tip end of the tooth is θ3 in electrical angle,
The notch is formed to satisfy θ3> 46 °.
The permanent magnet type rotary electric machine according to any one of claims 1 to 4, characterized in that: When the gap width between the tip end face 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 rotary electric machine according to any one of claims 1 to 5, characterized in that:

Images