Axial gap motor

Abstract

To provide a technology capable of reducing losses in an axial gap motor.SOLUTION: An axial gap motor 1 includes a stator 10 and a rotor 20 that faces the stator 10 in the axial direction along the rotation axis AX. The rotor 20 includes a plurality of permanent magnets 21 that are arranged circumferentially such that the magnetic poles facing the stator 10 alternate. At least one permanent magnet 21 of the plurality of permanent magnets 21 is divided into a plurality of magnet members 23 in the circumferential direction. The plurality of magnet members 23 include a magnet member 23c located in the circumferential center and a magnet member 23e located at an end in the circumferential direction. The axial gap motor 1 is configured such that the magnetic flux density generated in the circumferential arrangement from the magnet member 23c to the magnet member 23e decreases overall.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to an axial gap motor. [Background technology]

[0002] 2. Description of the Related Art An axial gap motor is known in which an armature and a permanent magnet field face each other in the axial direction along the rotating shaft (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-78243 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, it is desirable to reduce losses in an axial gap motor.

[0005] In view of the above problems, an object of the present invention is to provide a technique capable of reducing losses in an axial gap motor. [Means for solving the problem]

[0006] In order to achieve the above object, in one embodiment of the present disclosure, An armature, a field magnet opposed to the armature in an axial direction along a rotation axis, the field magnet includes a plurality of permanent magnets arranged in a circumferential direction such that magnetic poles facing the armature are alternately switched, At least one of the plurality of permanent magnets is divided into a plurality of magnet members in a circumferential direction, The plurality of magnet members include a first magnet member located at a circumferential center and a second magnet member located at an end in the circumferential direction, and are configured such that the magnetic flux density generated between the first magnet member and the second magnet member in the circumferential direction decreases as a whole. An axial gap motor is provided. Effect of the Invention

[0007] According to the above-described embodiment, the loss of the axial gap motor can be reduced. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a first example of an axial gap motor. [Diagram 2] FIG. 1 is a side view showing a first example of an axial gap motor. [Diagram 3] FIG. 11 is a diagram showing a second example of a permanent magnet. [Figure 4] FIG. 13 is a diagram showing a third example of a permanent magnet. [Diagram 5] FIG. 13 is a diagram showing a fourth example of a permanent magnet. [Figure 6] FIG. 13 is a diagram showing a fifth example of a permanent magnet. [Figure 7] FIG. 13 is a diagram showing a sixth example of a permanent magnet. [Figure 8] FIG. 13 is a diagram showing a seventh example of a permanent magnet. [Figure 9] FIG. 13 is a diagram showing an eighth example of a permanent magnet. [Figure 10] FIG. 13 is a diagram showing a ninth example of a permanent magnet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings.

[0010] [First example of an axial gap motor] A first example of an axial gap motor 1 according to this embodiment will be described with reference to FIGS.

[0011] Fig. 1 is a perspective view showing a first example of an axial gap motor 1. Fig. 2 is a side view showing the first example of an axial gap motor 1. Specifically, Fig. 2 is a view showing the first example of an axial gap motor 1 when viewed from the outside along a radial direction based on a rotation axis AX of the axial gap motor 1 (hereinafter simply referred to as the "radial direction").

[0012] 1 and 2, only about 1 / 8 of the entire circumference of the stator 10 and rotor 20 in the circumferential direction based on the rotation axis AX (hereinafter simply referred to as the "circumferential direction") is depicted. Also, in Fig. 1 and 2, only one of the stators 10 arranged opposite both ends of the rotor 20 in the axial direction is depicted, and the other stator 10 is omitted. Also, in Fig. 2, the holder 22 is not shown.

[0013] As shown in Fig. 1, the axial gap motor 1 includes a stator (also referred to as "stator") 10 and a rotor (also referred to as "rotor") 20. The axial gap motor 1 is configured such that the stator 10 and the rotor 20 face each other with a predetermined gap (also referred to as "air gap") in the axial direction (hereinafter simply referred to as "axial direction") along the rotation axis AX. Specifically, in this example, the axial gap motor 1 has a single rotor double stator structure in which the stators 10 are disposed to face both ends of the rotor 20 in the axial direction.

[0014] Furthermore, the axial gap motor 1 may have a structure different from the single rotor / double stator structure, such as a single rotor / single stator structure in which the stator 10 is arranged opposite only one of the axial ends of the rotor 20.

[0015] For example, the axial gap motor 1 is a synchronous machine that is driven by an externally supplied three-phase AC current.

[0016] The stator 10 is fixed to a housing (not shown) of the axial gap motor 1. In this example, the stator 10 is an armature, and as described above, is disposed opposite each of both ends in the axial direction of the rotor 20. The stator 10 includes a stator core (also referred to as a "stator core") 11 and windings (also referred to as "coils") 12.

[0017] Stator core 11 is made of a soft magnetic material and functions as a magnetic path for the magnetic field generated by the armature current of windings 12. Stator core 11 is made of, for example, a powder magnetic core. This increases the three-dimensional shape freedom of stator core 11, and makes it possible to realize a shape of stator core 11 that is more appropriate in terms of magnetic performance, strength performance, and the like. Stator core 11 may also be made of electromagnetic steel sheets or the like. In this case, it is desirable to laminate the electromagnetic steel sheets so as not to face the direction in which magnetic flux flows. This makes it possible to suppress the generation of eddy currents in each of the laminated electromagnetic steel sheets and reduce eddy current loss.

[0018] The stator core 11 includes a back yoke portion 13 and a plurality of teeth portions 14 .

[0019] When viewed along the axial direction, the back yoke portion 13 has a substantially annular shape centered on the rotation axis AX of the axial gap motor 1, and has a through hole that penetrates in the axial direction centered on the rotation axis AX. This allows a shaft attached to the rotor 20 to be inserted into the through hole, and the shaft can be supported rotatably around the rotation axis AX at both axial ends of the axial gap motor 1. The back yoke portion 13 magnetically short-circuits the multiple teeth portions 14 around which the electric wire of the windings 12 is wound, and forms a magnetic path for a magnetic field caused by a current flowing through each winding 12.

[0020] Incidentally, the term "abbreviated" is intended to allow for manufacturing errors and the like, and will be used in the following description with the same intention.

[0021] Teeth portion 14 is provided so as to protrude in the axial direction from a surface of back yoke portion 13 that faces rotor 20 in the axial direction. A plurality of teeth portions 14 (24 in this example) are arranged at equal intervals in the circumferential direction. As shown in Figures 1 and 2, in this example, the tip portion of teeth portion 14 in the axial direction is wider in a brim-like shape than the portion surrounded by winding 12.

[0022] The number of teeth 14 may be 23 or less, or 25 or more.

[0023] The windings 12 are formed by winding an electric wire (magnet wire) around the teeth 14, and an armature current flows through them. For example, the windings 12 are formed by winding an electric wire around each tooth 14 using a concentrated winding method. The windings 12 may also be formed by winding an electric wire across multiple teeth 14 using a distributed winding method.

[0024] Electrical insulation is ensured between stator core 11 and windings 12 by an insulating portion.

[0025] For example, the insulating portion is an insulating film made of PET (Polyethylene Terephthalate) and disposed between stator core 11 and windings 12. In addition, the insulating portion may be an insulating coating formed on the electric wire of windings 12.

[0026] The rotor 20 is attached to a shaft (not shown), and the shaft is supported via bearings on a fixed part such as a housing of the axial gap motor 1, thereby allowing the rotor 20 to rotate relative to the fixed part. In this example, the rotor 20 is a permanent magnet field magnet, and as described above, is disposed so as to face the stator 10 with a predetermined gap in the axial direction.

[0027] The rotor 20 includes a plurality of permanent magnets 21 and a holder 22 .

[0028] The permanent magnet 21 generates a magnetic field that links with the stator 10 serving as an armature. The permanent magnet 21 is, for example, a neodymium sintered magnet. The permanent magnet 21 may also be another type of permanent magnet, such as a samarium-cobalt magnet or a ferrite magnet.

[0029] The multiple (16 in this example) permanent magnets 21 all have approximately the same shape and are arranged at predetermined radial positions on the rotor 20, specifically, at radial positions where the windings 12 are provided, at approximately equal intervals.

[0030] The number of permanent magnets 21 may be 15 or less, or 17 or more.

[0031] The permanent magnets 21 are magnetized so that different magnetic poles are formed on both end faces in the axial direction. The multiple permanent magnets 21 are arranged so that the polarity of the magnetic pole on the surface facing the stator 10 is different from that of the other permanent magnets 21 adjacent in the circumferential direction. In other words, the multiple permanent magnets 21 are arranged so that the polarity of the magnetic pole on the surface facing the stator 10 alternates between N poles and S poles in the circumferential direction.

[0032] The holder 22 holds the permanent magnets 21. When viewed along the axial direction, the holder 22 has a substantially annular shape centered on the rotation axis AX of the axial gap motor 1, and has a through hole that passes through in the axial direction centered on the rotation axis AX. This allows the rotor 20 to be attached to a shaft, for example, by inserting the shaft through the through hole and fixing the shaft to the holder 22.

[0033] The holder 22 is provided with slots (magnet slots) for embedding the permanent magnets 21. The magnet slots have a shape that is approximately the same as or slightly larger than the permanent magnets 21, and are arranged at approximately equal intervals in the circumferential direction in accordance with the arrangement of the permanent magnets 21. The magnet slots are also provided so as to penetrate in the axial direction.

[0034] The holder 22 is formed of a non-magnetic material such as SUS steel (stainless steel). This allows the holder 22 to have a relatively high strength. The holder 22 may also be formed of a non-magnetic and non-metallic material such as resin. This allows the holder 22 to suppress the generation of eddy currents caused by the linkage of leakage flux of the permanent magnet 21, thereby suppressing energy loss (eddy current loss). The holder 22 may also be formed of a soft magnetic material such as a powder magnetic core. This allows, for example, a difference in inductance (saliency) between the d-axis and the q-axis to be realized by devising the detailed shape of the holder 22, and allows not only magnet torque but also reluctance torque to be utilized.

[0035] In this example, the multiple permanent magnets 21 are each divided into multiple magnet members 23. For example, the multiple magnet members 23 are each coated with an insulating coating such as epoxy resin. As a result, even if the permanent magnets 21 are formed of a highly conductive material such as a neodymium sintered magnet, it is possible to make it difficult for a path of eddy currents to be formed that cross the boundaries between the magnet members 23 due to the interlinkage magnetic flux from the stator 10. Therefore, it is possible to suppress energy loss (eddy current loss) in the permanent magnets 21. In addition, each of the multiple magnet members 23 may be plated with a material such as nickel that has a lower conductivity than the magnet members 23. This increases the contact resistance between the adjacent magnet members 23, and suppresses eddy currents that may be generated by the interlinkage magnetic flux from the stator 10 and cross the boundaries between the magnet members 23. Therefore, it is possible to suppress energy loss (eddy current loss) in the permanent magnets 21. In addition, by suppressing the eddy current in the permanent magnets 21, it is possible to suppress a rise in temperature of the permanent magnets 21 due to the generation of eddy currents. Therefore, it is possible to suppress a decrease in the residual magnetic flux density of the permanent magnets 21 and the occurrence of demagnetization.

[0036] 1 and 2, the permanent magnet 21 includes three magnet members 23 divided in the circumferential direction. The three magnet members 23 each have substantially the same shape and are arranged so as to be substantially flush in the axial direction. Furthermore, the three magnet members 23 may each be the same type of permanent magnet having substantially the same residual magnetic flux density.

[0037] When a single rotor / single stator structure is adopted, an iron core (back yoke) made of a soft magnetic material may be provided on the surface of the multiple permanent magnets 21 opposite to the surface facing the stator 10. This allows the back yoke to function as a magnetic path for magnetic flux between the multiple permanent magnets 21, making it possible to suppress leakage magnetic flux that shorts out at each permanent magnet 21.

[0038] Thus, in this example, the permanent magnet 21 is composed of a plurality of divided magnet members 23. This makes it possible to suppress the generation of eddy currents caused by the magnetic flux from the stator 10 interlinking with the permanent magnet 21. As a result, it is possible to suppress energy loss in the axial gap motor 1, and also to suppress a decrease in the residual magnetic flux density of the permanent magnet 21 and the occurrence of demagnetization.

[0039] [Second example of an axial gap motor] Next, a second example of the axial gap motor 1 according to this embodiment will be described with reference to FIG.

[0040] Hereinafter, the same reference numerals will be used for the same or corresponding configurations as in the first example described above, and the description will focus on the parts that are different from the first example described above, and the description of the same or corresponding contents as in the first example may be omitted. The third and subsequent examples described below will also be handled in the same manner in relation to the embodiments already described.

[0041] Fig. 3 is a diagram showing a second example of the permanent magnet 21. Specifically, Fig. 3 is a cross-sectional view of the permanent magnet 21 by a circular arc surface at a predetermined position in the radial direction, as viewed from the radial outside along the radial direction. The same applies to Figs. 4 to 10 described below.

[0042] The axial gap motor 1 according to this example is the same as the first example described above, except for the configuration of the permanent magnet 21. Therefore, the overall configuration of the axial gap motor 1 according to this example is not shown, and Figs. 1 and 2 are used. The same applies to the third to ninth examples described below.

[0043] As shown in FIG. 3, in this example, the permanent magnet 21 includes three magnet members 23 divided in the circumferential direction, similar to the first example described above.

[0044] As in the first example described above, the three magnet members 23 are the same type of permanent magnets having substantially the same residual magnetic flux density and have substantially the same circumferential width. For example, the three magnet members 23 have substantially the same shape when viewed along the axial direction.

[0045] In this example, the three magnet members 23 are divided into one magnet member 23c and two magnet members 23e.

[0046] The magnet member 23c is the circumferentially middle magnet member 23 among the three magnet members 23, and is located at the circumferential center portion of the permanent magnet 21. The two magnet members 23e are magnet members 23 arranged adjacent to both ends of the magnet member 23c in the circumferential direction, and are located at both ends of the permanent magnet 21 in the circumferential direction.

[0047] The magnet member 23c and the magnet member 23e have different axial dimensions (thicknesses). Specifically, the magnet member 23c has a larger axial dimension than the magnet member 23e. This makes the magnetic flux density generated by the magnet member 23c higher than that of the magnet member 23e. Therefore, the waveform of the circumferential magnetic flux density generated by the permanent magnet 21 can be made closer to a sine wave from a rectangular wave, and as a result, the harmonic components of the magnetic flux density waveform can be reduced. Therefore, the harmonic components of the torque generated with the rotation of the rotor 20 can be suppressed, and for example, the cogging torque under no-load conditions can be suppressed. In addition, since the harmonic components of the magnetic flux linking the permanent magnet 21 to the stator 10 are suppressed, the iron loss of the stator core 11 can be suppressed.

[0048] 3, the two magnet members 23e have substantially the same axial dimension (thickness) and are arranged so as to be substantially flush in the axial direction. The magnet member 23c is arranged so as to protrude from both one and the other axial end faces of the magnet member 23e by the same amount in the axial direction.

[0049] Thus, in this example, the three magnet members 23 are configured so that the magnetic flux density generated by the two magnet members 23e arranged at both ends in the circumferential direction is lower than that generated by the magnet member 23c arranged at the circumferential center of the permanent magnet 21. This makes it possible to change the waveform of the circumferential magnetic flux density generated by the permanent magnet 21 from a rectangular wave to a sine wave, thereby reducing harmonic components. Therefore, it is possible to suppress the harmonic components of the torque generated with the rotation of the rotor 20 and thereby suppress the cogging torque, and it is also possible to suppress the harmonic components of the magnetic flux from the permanent magnet 21 that links with the stator 10 and thereby suppress the iron loss of the stator core 11.

[0050] [Third example of an axial gap motor] Next, a third example of the axial gap motor 1 according to this embodiment will be described with reference to FIG.

[0051] FIG. 4 is a diagram showing a third example of the permanent magnet 21. As shown in FIG.

[0052] 4, in this example, unlike the first and second examples described above, the permanent magnet 21 includes four magnet members 23 divided in the circumferential direction. The four permanent magnets 21 are the same type of permanent magnets having approximately the same residual magnetic flux density, and have approximately the same circumferential width. For example, the four permanent magnets 21 have approximately the same shape when viewed along the axial direction.

[0053] In this example, the four magnet members 23 are divided into two magnet members 23c and two magnet members 23e.

[0054] The two magnet members 23c are the two magnet members 23 located in the middle of the four magnet members 23 in the circumferential direction, and are located at the center of the permanent magnet 21 in the circumferential direction. The two magnet members 23c are adjacent to each other so as to abut at the center (center) of the permanent magnet 21 in the circumferential direction, and are arranged symmetrically in the circumferential direction with the circumferential center as the reference. The two magnet members 23e are located at both ends of the permanent magnet 21 in the circumferential direction. Of the two magnet members 23e, one magnet member 23e is arranged adjacent to one magnet member 23c, and the other magnet member 23e is arranged adjacent to the other magnet member 23c.

[0055] The magnet members 23c and 23e have different axial dimensions (thicknesses), similar to the second example described above. Specifically, the magnet member 23c has a larger axial dimension than the magnet member 23e. As a result, similar to the second example described above, the magnetic flux density generated by the magnet member 23c is higher than that of the magnet member 23e. Therefore, it is possible to suppress the harmonic components of the torque generated with the rotation of the rotor 20, and to suppress, for example, the cogging torque under no-load conditions. In addition, since the harmonic components of the magnetic flux linking from the permanent magnet 21 to the stator 10 are suppressed, it is possible to suppress the iron loss of the stator core 11.

[0056] For example, as shown in Fig. 4, the two magnet members 23e have approximately the same axial dimension (thickness) and are arranged so as to be approximately flush with each other in the axial direction. The two magnet members 23c have approximately the same axial dimension and are arranged so as to be approximately flush with each other in the axial direction. The magnet members 23c are arranged so as to protrude the same amount in the axial direction from both one end face and the other end face of the magnet member 23e in the axial direction.

[0057] In this way, in this example, the four magnet members 23 are configured so that the magnetic flux density generated by the two magnet members 23e arranged at both ends in the circumferential direction is lower than that generated by the two magnet members 23c arranged in the circumferential center of the permanent magnet 21. As a result, similar to the second example described above, it is possible to suppress the harmonic components of the torque generated with the rotation of the rotor 20 and suppress the cogging torque, and it is also possible to suppress the harmonic components of the magnetic flux from the permanent magnet 21 that links with the stator 10 and suppress the iron loss of the stator core 11.

[0058] [Fourth example of an axial gap motor] Next, a fourth example of the axial gap motor 1 according to this embodiment will be described with reference to FIG.

[0059] FIG. 5 is a diagram showing a fourth example of the permanent magnet 21. In FIG.

[0060] 5, in this example, unlike the above-mentioned first to third examples, the permanent magnet 21 includes five magnet members 23 divided in the circumferential direction. The five magnet members 23 are the same type of permanent magnets having approximately the same residual magnetic flux density, and have approximately the same circumferential width. For example, the five magnet members 23 have approximately the same shape when viewed along the axial direction.

[0061] In this example, the five magnet members 23 include one magnet member 23c, two magnet members 23e, and two magnet members 23m.

[0062] The magnet member 23c is the magnet member 23 located in the middle of the five magnet members 23 in the circumferential direction, and is located at the center of the permanent magnet 21 in the circumferential direction. The two magnet members 23e are located at both ends of the permanent magnet 21 in the circumferential direction, respectively. The magnet member 23m is located between the magnet member 23c and the magnet member 23e. Specifically, of the two magnet members 23m, one magnet member 23m is disposed between the magnet member 23c and one magnet member 23e so as to be adjacent to both, and the other magnet member 23m is disposed between the magnet member 23c and the other magnet member 23e so as to be adjacent to both.

[0063] The magnet members 23c, 23m, and 23c have different axial dimensions (thicknesses). Specifically, the magnet member 23c has a larger axial dimension than the magnet member 23m, and the magnet member 23m has a larger axial dimension than the magnet member 23e. As a result, the magnetic flux density generated by the magnet member 23c is higher than that of the magnet member 23m, and the magnetic flux density generated by the magnet member 23m is higher than that of the magnet member 23e. Therefore, the waveform of the circumferential magnetic flux density generated by the permanent magnet 21 can be made closer to a sine wave from a rectangular wave, and as a result, the harmonic components of the magnetic flux density waveform can be further reduced. Therefore, the harmonic components of the torque generated with the rotation of the rotor 20 can be further suppressed, and for example, the cogging torque under no-load conditions can be further suppressed. In addition, the harmonic components of the magnetic flux linking the permanent magnet 21 to the stator 10 are further suppressed, so that the iron loss of the stator core 11 can be further suppressed.

[0064] For example, as shown in Fig. 5, the two magnet members 23e have approximately the same axial dimension (thickness) and are arranged so as to be approximately flush in the axial direction. The two magnet members 23m have approximately the same axial dimension and are arranged so as to be approximately flush in the axial direction. The magnet members 23m are arranged so as to protrude the same amount in the axial direction from both one end face and the other end face of the magnet member 23e in the axial direction. The magnet member 23c is arranged so as to protrude the same amount in the axial direction from both one end face and the other end face of the magnet member 23m in the axial direction.

[0065] Thus, in this example, the five magnet members 23 are arranged such that the magnetic flux density generated monotonically decreases in the line from magnet member 23c to magnet member 23e, sandwiching magnet member 23m therebetween. This makes it possible to change the waveform of the circumferential magnetic flux density generated by the permanent magnets 21 from a rectangular wave to a sine wave, thereby further reducing harmonic components. As a result, it is possible to further suppress the harmonic components of the torque generated with the rotation of the rotor 20 and further suppress the cogging torque, and it is also possible to further suppress the harmonic components of the magnetic flux from the permanent magnets 21 that link with the stator 10 and further suppress the iron loss of the stator core 11.

[0066] [Fifth example of an axial gap motor] Next, a fifth example of the axial gap motor 1 according to this embodiment will be described with reference to FIG.

[0067] FIG. 6 is a diagram showing a fifth example of the permanent magnet 21. In FIG.

[0068] 6, in this example, unlike the above-mentioned first to fourth examples, the permanent magnet 21 includes six magnet members 23 divided in the circumferential direction. The six magnet members 23 are the same type of permanent magnets having approximately the same residual magnetic flux density, and have approximately the same circumferential width. For example, the six magnet members 23 have approximately the same shape when viewed along the axial direction.

[0069] In this example, the six magnet members 23 are divided into two magnet members 23c, two magnet members 23e, and two magnet members 23m.

[0070] The two magnet members 23c are the two magnet members 23 located in the middle of the six magnet members 23 in the circumferential direction, and are located at the center of the permanent magnet 21 in the circumferential direction. The two magnet members 23c are adjacent to each other so as to abut at the center (center) of the permanent magnet 21 in the circumferential direction, and are arranged symmetrically in the circumferential direction with the circumferential center as a reference. The two magnet members 23e are located at both ends of the permanent magnet 21 in the circumferential direction, respectively. The magnet member 23m is located between the magnet member 23c and the magnet member 23e. Specifically, with the center (center) of the permanent magnet 21 in the circumferential direction as a reference, one of the two magnet members 23m is arranged between one magnet member 23c and one magnet member 23e so as to be adjacent to both of them. Similarly, with respect to the circumferential center (center) of the permanent magnet 21 as a reference, the other of the two magnet members 23m, 23m, is positioned between the other magnet member 23c and the other magnet member 23e so as to be adjacent to both of them.

[0071] The magnet members 23c, 23m, and 23c have different axial dimensions (thicknesses) as in the fourth example described above. Specifically, the magnet member 23c has a larger axial dimension than the magnet member 23m, and the magnet member 23m has a larger axial dimension than the magnet member 23e. As a result, as in the fourth example described above, the magnetic flux density generated by the magnet member 23c is larger than that of the magnet member 23m, and the magnetic flux density generated by the magnet member 23m is larger than that of the magnet member 23e. Therefore, the harmonic components of the torque generated with the rotation of the rotor 20 can be further suppressed, and for example, the cogging torque under no-load conditions can be further suppressed. In addition, the harmonic components of the magnetic flux linking from the permanent magnet 21 to the stator 10 are further suppressed, so that the iron loss of the stator core 11 can be further suppressed.

[0072] For example, as shown in FIG. 6, the two magnet members 23e have substantially the same axial dimension (thickness) and are arranged to be substantially flush in the axial direction, as in the fourth example described above. The two magnet members 23m have substantially the same axial dimension and are arranged to be substantially flush in the axial direction, as in the fourth example described above. The two magnet members 23c have substantially the same axial dimension and are arranged to be substantially flush in the axial direction. As in the fourth example described above, the magnet members 23m are arranged to protrude the same amount in the axial direction from both one end face and the other end face of the magnet member 23e, and the magnet members 23c are arranged to protrude the same amount in the axial direction from both one end face and the other end face of the magnet member 23e.

[0073] Thus, in this example, the six magnet members 23 are arranged such that the magnetic flux density generated monotonically decreases in the line from magnet member 23c to magnet member 23e, sandwiching magnet member 23m. This makes it possible to change the waveform of the circumferential magnetic flux density generated by the permanent magnets 21 from a rectangular wave to a sine wave, thereby further reducing harmonic components. As a result, it is possible to further suppress the harmonic components of the torque generated with the rotation of the rotor 20 and further suppress the cogging torque, and it is also possible to further suppress the harmonic components of the magnetic flux from the permanent magnets 21 that link with the stator 10 and further suppress the iron loss of the stator core 11.

[0074] [Axial Gap Motor Examples 6 to 9] Next, sixth to ninth examples of the axial gap motor 1 will be described with reference to FIGS.

[0075] 7 to 10 are diagrams showing sixth to ninth examples of the axial gap motor 1. FIG.

[0076] In the sixth to ninth examples, unlike the second to fifth examples described above, the multiple magnet members 23 included in the permanent magnet 21 have different circumferential dimensions (widths) of the magnet members 23 arranged between the magnet member 23c located in the circumferential center and the magnet member 23e located at the end. As a result, for example, by adjusting the circumferential dimensions of the magnet members 23, it is possible to more appropriately adjust the waveform of the circumferential magnetic flux density generated by the permanent magnet 21, and as a result, it is possible to further reduce harmonic components.

[0077] 7, in this example (sixth example), as in the above-mentioned second example, the permanent magnet 21 includes three divided magnet members 23, specifically, one magnet member 23c and two magnet members 23e. In this example, the circumferential dimensions of the two magnet members 23e are approximately the same, and the circumferential dimension of the magnet member 23c is larger than that of the magnet member 23e.

[0078] 8, in this example (seventh example), as in the above-mentioned third example, the permanent magnet 21 includes four divided magnet members 23, specifically, two magnet members 23c and two magnet members 23e. In this example, the circumferential dimensions of the two magnet members 23e and the circumferential dimensions of the two magnet members 23c are approximately the same, and the circumferential dimension of the magnet member 23c is larger than that of the magnet member 23e.

[0079] 9, in this example (eighth example), as in the above-mentioned fourth example, the permanent magnet 21 includes five divided magnet members 23, specifically, one magnet member 23c, two magnet members 23e, and two magnet members 23m. In this example, the circumferential dimensions of the two magnet members 23e and the circumferential dimensions of the two magnet members 23m are approximately the same. The circumferential dimension of the magnet member 23c is larger than that of the magnet member 23m, and the circumferential dimension of the magnet member 23m is larger than that of the magnet member 23e.

[0080] 10, in this example (ninth example), as in the fifth example described above, the permanent magnet 21 includes six divided magnet members 23, specifically, two magnet members 23c, two magnet members 23e, and two magnet members 23m. In this example, the circumferential dimensions of the two magnet members 23c, the circumferential dimensions of the two magnet members 23e, and the circumferential dimensions of the two magnet members 23m are approximately the same. The circumferential dimension of the magnet member 23c is larger than that of the magnet member 23m, and the circumferential dimension of the magnet member 23m is larger than that of the magnet member 23e.

[0081] In this way, in the present examples (sixth to ninth examples), the multiple magnet members 23 included in the permanent magnet 21 have different circumferential dimensions (widths) for the magnet members 23 arranged between the magnet member 23c located at the circumferential center and the magnet member 23e located at the end. This makes it possible to further reduce the harmonic components of the waveform of the circumferential magnetic flux density generated by the permanent magnet 21. Therefore, it is possible to further suppress the harmonic components associated with the rotation of the rotor 20 and further suppress the cogging torque, and it is possible to further suppress the harmonic components of the magnetic flux of the permanent magnet 21 that links with the stator 10 and further suppress the iron loss of the stator core 11.

[0082] [Example 10 of an axial gap motor] Next, a tenth example of the axial gap motor 1 according to the present embodiment will be described.

[0083] The axial gap motor 1 according to this example has the same configuration and shape as the above-described first example, so the overall configuration of the axial gap motor 1 according to this example will not be illustrated, and Figs. 1 and 2 will be used instead.

[0084] The axial gap motor 1 according to this example differs from the above-mentioned first example in that the residual magnetic flux density differs between the magnet member 23 located in the circumferential center among the three magnet members 23 and the two magnet members 23 located at both ends in the circumferential direction, but may be the same as the above-mentioned first example in other respects. Hereinafter, in this example, as in the above-mentioned second to ninth examples, the magnet member 23 located in the circumferential center will be referred to as "magnet member 23c," and the magnet members 23 located at both ends in the circumferential direction will be referred to as "magnet member 23e."

[0085] In this example, the two magnet members 23e have substantially the same residual magnetic flux density, and the magnet member 23c has a higher residual magnetic flux density than the magnet member 23e. As a result, similar to the second example described above, the magnetic flux density generated by the magnet member 23c is higher than that of the magnet member 23e. Therefore, the waveform of the circumferential magnetic flux density generated by the permanent magnet 21 can be made closer to a sine wave from a rectangular wave, and as a result, the harmonic components of the magnetic flux density waveform can be reduced. Therefore, the harmonic components of the torque generated with the rotation of the rotor 20 can be suppressed, and for example, the cogging torque under no-load conditions can be suppressed. In addition, the harmonic components of the magnetic flux linking the permanent magnet 21 to the stator 10 are suppressed, so that the iron loss of the stator core 11 can be suppressed.

[0086] For example, when all three magnet members 23 are sintered neodymium magnets, the residual magnetic flux density of magnet member 23c can be made higher than that of magnet member 23e by making the content of heavy rare earth elements such as dysprosium (Dy) in magnet member 23c lower than that of magnet member 23e. Also, the residual magnetic flux density of magnet member 23c may be made higher than that of magnet member 23e by using a different type of permanent magnet between magnet member 23c and magnet member 23e.

[0087] In addition, demagnetization of the permanent magnet 21 often occurs at the corners. Therefore, even if the coercive force of the magnet member 23c is relatively reduced by relatively reducing the heavy rare earth content of the magnet member 23c located in the circumferential center, the possibility of problems such as demagnetization of the permanent magnet 21 occurring is extremely low.

[0088] Thus, in this example, similar to the second example described above, the three magnet members 23 are configured such that the magnetic flux density generated by the two magnet members 23e arranged at both ends in the circumferential direction is lower than that generated by the magnet member 23c arranged in the circumferential center of the permanent magnet 21. This makes it possible to suppress the harmonic components of the torque generated with the rotation of the rotor 20 and suppress the cogging torque, as well as to suppress the harmonic components of the magnetic flux from the permanent magnet 21 that links to the stator 10 and suppress the iron loss of the stator core 11, similar to the second example described above.

[0089] [Other examples of axial gap motors] Next, another example of the axial gap motor 1 according to the present embodiment will be described.

[0090] The axial gap motor 1 according to the above-described embodiments (first to tenth examples) may be modified or changed as appropriate.

[0091] For example, in the first example of the axial gap motor 1 described above, the permanent magnet 21 may be composed of two divided magnet members 23, or may be composed of four or more divided magnet members 23.

[0092] In the second and tenth examples of the axial gap motor 1 described above, the permanent magnet 21 may be composed of two divided magnet members 23. For example, one of the two magnet members 23e may be omitted, and the magnet member 23c may be arranged so as to expand to the circumferential range of the omitted magnet member 23e. In this case, the magnet member 23c is arranged to occupy 2 / 3 of the circumference, and the magnet member 23e is arranged to occupy the remaining 1 / 3 of the circumference.

[0093] Furthermore, in the third to ninth examples of the axial gap motor 1 described above and examples of variations and modifications thereof, instead of varying the axial dimensions of the magnet members 23, the residual magnetic flux density of the magnet members 23 may be varied, as in the tenth example described above, so that the waveform of the magnetic flux density in the circumferential direction of the permanent magnet 21 approaches a sine wave from a rectangular wave.

[0094] Furthermore, in the fourth, fifth, eighth, and ninth examples of the axial gap motor 1 described above and their modified and altered examples, the number of magnet members 23m arranged between magnet members 23c and 23e may be two or more.

[0095] Furthermore, in the above-mentioned fourth, fifth, eighth, and ninth examples of the axial gap motor 1 and examples of modifications and variations thereof, there may be locations where the magnetic flux density generated by adjacent magnet members 23 in the circumferential arrangement of magnet members 23 from magnet member 23c to magnet member 23e is the same. In other words, in the above-mentioned fourth, fifth, eighth, and ninth examples of the axial gap motor 1 and examples of modifications and variations thereof, the magnetic flux density generated in the circumferential arrangement of magnet members 23 from magnet member 23c to magnet member 23e may be configured to decrease overall without increasing.

[0096] Furthermore, in the eighth and ninth examples of the axial gap motor 1 described above and examples of variations and modifications thereof, among the arrangement of magnet members 23 in the circumferential direction between magnet member 23c and magnet member 23e, only the circumferential dimensions (widths) of some of the magnet members 23 may be different.

[0097] Furthermore, in the above-mentioned fourth, fifth, eighth, and ninth examples of the axial gap motor 1 and examples of their modifications and changes, the permanent magnet 21 may be divided into an asymmetric number of magnet members 23 in the circumferential direction with the circumferential center (center) as a reference. For example, in the above-mentioned fourth example of the axial gap motor 1, one of the two magnet members 23m may be omitted, and the circumferential dimensions of both magnet members 23c and 23e may be enlarged to make up for the circumferential range. In this case, the permanent magnet 21 has three magnet members 23 on one side of the circumferential direction with the circumferential center as a reference, and two magnet members 23 on the other side.

[0098] Furthermore, in the second to tenth examples of the axial gap motor 1 described above and examples of variations and modifications thereof, the axial dimensions of the magnet members 23 included in the permanent magnet 21 and the residual magnetic flux density may both be made different from each other, so that the circumferential waveform of the magnetic flux density generated by the permanent magnet 21 approaches a sine wave from a rectangular wave.

[0099] Furthermore, in the above-mentioned first to tenth examples of the axial gap motor 1 and their modified and altered examples, only some of the permanent magnets 21 included in the rotor 20 may be configured from a plurality of divided magnet members 23.

[0100] Furthermore, in the second to tenth examples of the axial gap motor 1 described above and examples of variations and modifications thereof, the circumferential waveform of the magnetic flux density generated by only some of the multiple permanent magnets 21 included in the rotor 20 may be configured to approach a sine wave from a rectangular wave.

[0101] [Effect] Next, the operation of the axial gap motor according to this embodiment will be described.

[0102] In a first aspect of this embodiment, the axial gap motor includes an armature and a field magnet that faces the armature in the axial direction along the rotation axis. The axial gap motor is, for example, the axial gap motor 1 described above. The armature is, for example, the stator 10 described above. The field magnet is, for example, the rotor 20 described above. Specifically, the field magnet includes a plurality of permanent magnets that are arranged in the circumferential direction so that the magnetic poles facing the armature are alternately switched. The permanent magnet is, for example, the permanent magnet 21 described above. At least one of the plurality of permanent magnets is divided into a plurality of magnet members in the circumferential direction. The magnet member is, for example, the magnet member 23 described above. The plurality of magnet members include a first magnet member located in the center in the circumferential direction and a second magnet member located at an end in the circumferential direction, and are configured such that the magnetic flux density generated between the circumferential arrangement from the first magnet member to the second magnet member decreases as a whole. The first magnet member is, for example, the magnet member 23c described above. The second magnet member is, for example, the above-mentioned magnet member 23e.

[0103] As a result, for example, a highly conductive permanent magnet can be treated so that the contact resistance between adjacent magnet members is increased or insulation is ensured. Therefore, eddy currents caused by the magnetic flux from the armature linking across the magnet members are less likely to flow, and as a result, eddy current loss in the permanent magnet can be suppressed. In addition, the circumferential waveform of the magnetic flux density generated by the permanent magnet can be made closer to a sine wave from a rectangular wave, and as a result, the harmonic components of the magnetic flux density waveform can be reduced. Therefore, the harmonic components of the magnetic flux linking from the permanent magnet to the armature are suppressed, and thus the iron loss of the armature can be suppressed. Therefore, the loss of the axial gap motor can be suppressed. In addition, the harmonic components of the torque generated by the rotation of the rotor can be suppressed, and as a result, the cogging torque can be suppressed.

[0104] In addition, in a second aspect of this embodiment, based on the above-mentioned first aspect, the multiple magnet members may include two second magnet members located at both ends in the circumferential direction.

[0105] As a result, the magnetic flux density of the permanent magnet decreases overall in both circumferential directions with the center of the circumferential range as the reference point, making the magnetic flux density waveform closer to a sine wave, and as a result, the harmonic components of the magnetic flux density waveform can be further reduced.

[0106] In a third aspect of the present embodiment, based on the first or second aspect described above, the plurality of magnet members may include a third magnet member located between the first and second magnet members in the circumferential direction. The third magnet member is, for example, the magnet member 23m described above.

[0107] This allows the permanent magnet to have a wider range of adjustment for the change in magnetic flux density in the circumferential direction, making the magnetic flux density waveform closer to a sine wave, and as a result, making it possible to further suppress harmonic components in the magnetic flux density waveform.

[0108] In addition, in a fourth aspect of this embodiment, based on the third aspect described above, the multiple magnet members may be configured so that the magnetic flux density generated between the circumferential arrangement from the first magnet member to the second magnet member monotonically decreases.

[0109] This allows the waveform of the magnetic flux density to be closer to a sine wave, and as a result, the harmonic components of the waveform of the magnetic flux density can be further suppressed.

[0110] In addition, in a fifth aspect of this embodiment, based on any one of the first to fourth aspects described above, the multiple magnet members may have different circumferential widths for at least a portion of the circumferential arrangement from the first magnet member to the second magnet member.

[0111] This allows the permanent magnet to have a wider range of adjustment for the change in magnetic flux density in the circumferential direction, making the magnetic flux density waveform closer to a sine wave, and as a result, making it possible to further suppress harmonic components in the magnetic flux density waveform.

[0112] In addition, in a sixth aspect of this embodiment, assuming any one of the first to fifth aspects described above, the multiple magnet members may be configured such that the overall axial dimensions of each of the magnet members decrease between the first magnet member and the second magnet member in a circumferential arrangement.

[0113] This makes it possible to configure the multiple magnet members so that the magnetic flux density generated between the first magnet member and the second magnet member in the circumferential direction is reduced overall.

[0114] In addition, in a seventh aspect of this embodiment, based on any one of the first to sixth aspects described above, the multiple magnet members may be configured so that the residual magnetic flux density of each magnet member decreases overall between the circumferential arrangement from the first magnet member to the second magnet member.

[0115] This makes it possible to configure the multiple magnet members so that the magnetic flux density generated between the first magnet member and the second magnet member in the circumferential direction is reduced overall.

[0116] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0117] 1 Axial Gap Motor 10 Stator 11 Stator core 12 Windings 13 Back yoke 14 Teeth 20 Rotor 21 Permanent magnets 22 Holder 23 Magnet parts 23c Magnet parts 23e Magnet parts 23m Magnet parts AX Rotation axis center

Claims

1. An armature, a field magnet opposed to the armature in an axial direction along a rotation axis, the field magnet includes a plurality of permanent magnets arranged in a circumferential direction such that magnetic poles facing the armature are alternately switched, At least one of the plurality of permanent magnets is divided into a plurality of magnet members in a circumferential direction, The plurality of magnet members include a first magnet member located at a circumferential center and a second magnet member located at an end in the circumferential direction, and are configured such that a magnetic flux density generated between the first magnet member and the second magnet member in the circumferential direction decreases as a whole. Axial gap motor.

2. The plurality of magnet members includes two of the second magnet members located at both ends in a circumferential direction.

2. The axial gap motor according to claim 1.

3. the plurality of magnet members includes a third magnet member located between the first magnet member and the second magnet member in the circumferential direction; 3. The axial gap motor according to claim 1 or 2.

4. The plurality of magnet members are configured such that a magnetic flux density generated between the first magnet member and the second magnet member in a circumferential direction decreases monotonically. The axial gap motor according to claim 3 .

5. The plurality of magnet members have different circumferential widths in at least a portion of a circumferential arrangement from the first magnet member to the second magnet member.

3. The axial gap motor according to claim 1 or 2.

6. the plurality of magnet members are configured such that the respective axial dimensions decrease overall between the first magnet member and the second magnet member in a circumferential arrangement; 3. The axial gap motor according to claim 1 or 2.

7. the plurality of magnet members are configured such that the residual magnetic flux density of each of the magnet members decreases overall between the first magnet member and the second magnet member in a circumferential direction; 3. The axial gap motor according to claim 1 or 2.

Images