Axial gap type rotating motor

Abstract

The present invention includes: a plurality of stator cores (21) having coils (24) wound around an iron core (22); a stator (2) formed by arranging the plurality of stator cores (21) in a ring shape; a rotor (3) facing the stator (2) across an air gap; a housing (5) covering the stator (2); a molded resin (9) sealing the side of the iron core (22), the molded resin having an opposing surface (91) facing the rotor (3); an annular first conductor (11) electrically connected to the housing (5), the first conductor being arranged on the opposing surface (91) so as to surround the iron core (22), the first conductor having a notch (13) formed in a portion of the periphery of the iron core (22); and a second conductor (12) being arranged to electrically connect the first conductor (11) to the iron core (22), the second conductor being located on the opposing surface on at least one of the inner diameter side and the outer diameter side of the stator (2) in the iron core (22).

Description

Technical Field

[0001] The present invention relates to an axial gap type rotating electrical machine. Background Art

[0002] In axial-gap rotating electrical machines, where the stator and rotor face each other across a predetermined air gap in the axial direction, the electrostatic capacitance between the coils and the rotor tends to increase, leading to the generation of shaft voltage. In particular, in stators where the stator core is sealed with a molded resin, the stator core is electrically insulated by the molded resin, resulting in a floating potential. This further increases the electrostatic capacitance between the coils and the rotor, further increasing the shaft voltage. When this shaft voltage exceeds the dielectric breakdown voltage of the bearing oil film, electrical corrosion occurs in the bearing, shortening its life. Patent Document 1 discloses a technique for reducing this shaft voltage.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6208331 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] In the axial gap rotating electric machine disclosed in Patent Document 1, a plate-shaped conductor electrically connects the outer diameter side surface of the stator in the iron core to the housing, setting the iron core to ground potential and reducing shaft voltage. Furthermore, a strip-shaped conductor is arranged on the surface of the bobbin flange facing the rotor to shield the coil from the rotor, reducing electrostatic capacitance and further reducing shaft voltage. However, the plate-shaped and strip-shaped conductors require pre-processing to conform to the location where they will be installed.

[0008] The inventors then realized that using alternative components that did not require pre-processing to fit the required mounting location to electrically connect the core to the housing and to shield the coils from the rotor would improve production efficiency. Furthermore, the inventors concluded that gaps between the core and the molded resin, or between the core and the bobbin, could develop due to aging, and that this consideration should be taken into account when using these alternative components to electrically connect the core to the housing.

[0009] An object of the present invention is to provide an axial gap rotating electrical machine that can improve the production efficiency of a stator and prevent disconnection of the electrical connection between the core and the housing due to aging.

[0010] Technical solutions to problems

[0011] In order to achieve the above-mentioned purpose, the present invention includes: a plurality of stator cores with coils wound on an iron core; a stator composed of the plurality of stator cores arranged in a ring shape; a rotor opposite to the stator across an air gap; a shell covering the stator; a molded resin sealing the side of the iron core, which has an opposing surface opposite to the rotor; an annular first conductor electrically connected to the shell, which is arranged on the opposing surface in a manner surrounding the circumference of the iron core and has a notch formed in a portion of the circumference of the iron core; and a second conductor arranged to electrically connect the first conductor and the iron core, which is located on at least one of the inner diameter side and the outer diameter side of the stator of the iron core on the opposing surface.

[0012] Effects of the Invention

[0013] The axial gap rotating electrical machine of the present invention can improve the production efficiency of the stator and prevent the occurrence of electrolytic corrosion due to aging and shortening of the life span. Other problems, structures and effects than those described above will be explained through the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional perspective view of an axial gap type rotating electrical machine of a comparative example.

[0015] Figure 2 It is an axial cross-sectional view of a casing and a stator of an axial gap type rotating electrical machine of a comparative example.

[0016] Figure 3 It is a perspective view of a stator, a rotor, and a housing of an axial gap type rotating electrical machine of a comparative example.

[0017] Figure 4 This is a schematic diagram of a case and a stator of an axial gap type rotating electrical machine according to a comparative example, viewed from the axial direction on the side where the conductor is provided.

[0018] Figure 5 This is a schematic diagram of a case and a stator of an axial gap type rotating electrical machine according to the first embodiment of the present invention as viewed from the rotor side.

[0019] Figure 6 This is a schematic diagram of a case and a stator of an axial gap type rotating electrical machine according to a second embodiment of the present invention, viewed from the rotor side.

[0020] Figure 7 This is a schematic diagram of a case and a stator of an axial gap type rotating electrical machine according to a third embodiment of the present invention, as viewed from the rotor side.

[0021] Figure 8 This is a schematic diagram of a case and a stator of an axial gap type rotating electrical machine according to a fourth embodiment of the present invention, as viewed from the rotor side.

[0022] Figure 9 It is an enlarged perspective view of a fitting portion of an axial gap rotating electrical machine according to a fourth embodiment of the present invention.

[0023] Figure 10 It is an axial cross-sectional view of a casing and a stator of an axial gap type rotating electrical machine according to a fifth embodiment of the present invention.

[0024] Figure 11 This is a schematic diagram of a case and a stator of an axial gap type rotating electrical machine according to a sixth embodiment of the present invention, as viewed from the rotor side.

[0025] Figure 12 It is an axial cross-sectional view of a casing and a stator of an axial gap type rotating electrical machine according to a sixth embodiment of the present invention. DETAILED DESCRIPTION

[0026] Hereinafter, the structure and operation of the axial gap rotating electrical machines according to the first to fifth embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals denote the same parts.

[0027] Figure 1 : is a cross-sectional perspective view of an axial gap type rotating electrical machine of a comparative example. Figure 1 As shown, the axial gap rotating electrical machine 100 of the comparative example is a twin-rotor type in which a stator is sandwiched between two rotors.

[0028] The axial gap rotating electrical machine 100 includes a stator 2 , two rotors 3 , a shaft 4 , a housing 5 , two bearings 6 , a front housing 7 , and a rear housing 8 .

[0029] The stator 2 is an armature composed of a plurality of stator cores 21 arranged in a ring shape. The stator core 21 includes an iron core 22, a winding frame 23, and a coil 24. The iron core 22 is an iron block formed by stacking soft magnetic sheets such as electromagnetic steel sheets punched into a predetermined shape in the radial direction of the stator 2. In addition, in order to reduce iron loss, it is preferable to use amorphous metal as the soft magnetic sheet. The winding frame 23 is a cylindrical resin. The iron core 22 is inserted into the winding frame 23. The coil 24 is an electric wire for generating a magnetic field and is wound on the winding frame 23.

[0030] The rotor 3 has multiple magnets 31, a back yoke 32, and a base 33. The multiple magnets 31 are annularly fixed to the surface of the base 33 on the stator 2 side, with the back yoke 32 interposed therebetween, and face the stator 2 across an air gap. The back yoke 32 is a wound iron core formed by winding a strip of electromagnetic steel sheet and is fixed to an annular groove 33a formed on the surface of the base 33 on the stator 2 side. The base 33 is a non-magnetic, circular plate-shaped body with an annular groove 33a and a through-hole 33b. The through-hole 33b is provided in the center of the base 33, and the shaft 4 is inserted therein.

[0031] The shaft 4 is a rotating shaft and is supported by two bearings 6. The two bearings 6 are fixed to the front housing 7 and the rear housing 8, respectively.

[0032] The housing 5 covers the stator 2. A front housing 7 and a rear housing 8 are mounted on the housing 5. The front housing 7 and the rear housing 8 are disc-shaped members mounted on both ends of the housing 5 to close the opening of the housing 5.

[0033] Figure 2 This is an axial cross-sectional view of the housing and stator of an axial gap type rotating electrical machine of a comparative example. On the housing 5, a disc-shaped guide portion 52 protrudes radially inward from the inner circumference of the cylindrical portion 51 covering the stator 2. The guide portion 52 positions the stator 2 at a predetermined location within the housing 5.

[0034] The stator 2, positioned at a predetermined location within the housing 5, is molded with a molding resin 9. The molding resin 9 is a molding material used to mold the stator 2 within the housing 5 so that the surface 521 of the guide portion 52 facing the rotor 3 is exposed. The molding resin 9 has an axial hole 25 serving as a through-hole at its center. Conductors 10 are provided on the surface 91 of the molding resin 9 facing the rotor 3, where the surface 521 of the guide portion 52 is exposed. Conductors 10 are in contact with the iron core 22 and the guide portion 52.

[0035] Figure 3 This is a perspective view of the stator, rotor, and housing of an axial gap type rotating electrical machine of a comparative example. In order to clearly illustrate the arrangement of the stator core 21 and the shape of the molded resin 9, the front side of the cylindrical portion of the housing 5, the conductor 10, and the guide portion 52 are omitted from the illustration. Figure 3 As shown, the stator 2 , which is formed by arranging a plurality of stator cores 21 in a ring shape, is molded with a molding resin 9 and fixed to the housing 5 .

[0036] Figure 4 1 is a schematic diagram showing the stator 2 and the housing 5 of an axial gap rotating electrical machine 100 according to a comparative example, as viewed from the axial direction on the side where the conductor 10 is provided.

[0037] As described above, the molded resin 9 has an axial hole 25 as a through-hole at its center, and the conductor 10 provided on the surface 91 facing the rotor 3 is in contact with the iron core 22 and the guide portion 52. Thus, the conductor 10 electrically connects the case 5 and the iron core 22. This grounds the iron core 22 through the case 5 via the conductor 10, preventing the potential of the iron core 22 from drifting and suppressing the generation of shaft voltage.

[0038] A liquid conductive member, such as a conductive paint or conductive adhesive (hereinafter referred to as conductive paint, etc.), which hardens after being applied (applied) is used as the conductor 10. Therefore, there is no need to pre-process the conductor 10 into a shape that matches the location where it is to be installed, which can improve production efficiency.

[0039] As base materials for conductive coatings, for example, epoxy resins, acrylic resins, polyurethane resins, polyester resins, and silicone resins can be used alone or in combination. Conductive particles used in conductive coatings, for example, include conductive materials such as silver, copper, gold, nickel, aluminum, and carbon. Low-resistance materials (i.e., highly conductive materials) such as silver and copper are particularly preferred. Alternatively, conductive particles in a paste-like form that solidifies after being heated and melted can be used for conductor 10.

[0040] Furthermore, the conductor 10 is preferably non-magnetic. This shields the electrostatic coupling caused by the common-mode voltage induced from the coil 24 to the rotor 3. This reduces the voltage applied to the bearing 6 and suppresses electrical corrosion of the bearing 6. Therefore, the non-magnetic conductor 10 is preferably provided across the entire surface of the stator 2 facing the rotor 3.

[0041] On the other hand, the comparative example axial gap rotating electric machine 100 has the following problem. Specifically, the conductor 10 applied to the surface 91 of the molded resin 9 facing the rotor 3 forms multiple annular portions 101 that surround the multiple iron cores 22. Therefore, current flows along each of the multiple annular portions 101, generating multiple eddy currents in the conductor 10. Furthermore, the conductor 10 applied to the surface 91 of the molded resin 9 facing the rotor 3 forms an annular portion 102 that surrounds the axial center hole 25. Therefore, eddy currents are generated in the conductor 10 along the annular portion 102. Consequently, the axial gap rotating electric machine 100 has the problem of reduced efficiency due to increased eddy current loss.

[0042] Furthermore, over long-term use, the axial gap rotating electric machine 100 may deform the sealing surfaces 92-95 of the molded resin 9 that seal the side surfaces of the core 22 and separate from the side surfaces of the core 22, creating gaps between the sealing surfaces 92-95 and the side surfaces of the core 22. When gaps form between the sealing surfaces 92-95 and the side surfaces of the core 22, the conductors 10 break, severing the electrical connection between them and the core 22. This causes the potential of the core 22 to become a floating potential, generating shaft voltage. Consequently, the comparative example axial gap rotating electric machine 100 has the problem of electrolytic corrosion in the bearings 6 over long-term use, resulting in a shortened lifespan.

[0043] (First embodiment)

[0044] Figure 5This is a schematic diagram showing the housing 5 and stator 2 of an axial gap rotating electric machine 1 according to the first embodiment of the present invention as viewed from the rotor 3 side. The axial gap rotating electric machine 1 of this embodiment differs from the axial gap rotating electric machine 100 of the comparative example in the structure, shape, and arrangement of the conductor 10.

[0045] The conductor 10 of the axial gap rotating electrical machine 1 of the present embodiment is composed of a first conductor 11 and a plurality of second conductors 12 (the same number as the iron core 22 ).

[0046] The first conductor 11 is an annular conductor having a notch 13 in a portion around the iron core 22 and provided on a surface 91 of the mold resin 9 that seals the stator core 21 and faces the rotor 3 , so as to surround the iron core 22 , and is electrically connected to the housing 5 .

[0047] Next, use Figure 5 The first conductor 11 of this embodiment is described in detail. The first conductor 11 is a conductive coating applied to the surface 91 of the molded resin 9 facing the rotor 3 and has an outer diameter portion 111, a plurality of intermediate portions 112, an inner diameter portion 113, and a plurality of notches 13.

[0048] The outer diameter portion 111 is a ring-shaped conductive coating applied to the surface 91 of the molded resin 9 facing the rotor 3, which seals the outer side surfaces of the annularly arranged plurality of iron cores 22. A first insulating tape 141, projecting from the surface 91 of the molded resin 9 facing the rotor 3, is provided between the outer diameter portion 111 and each iron core 22. Thus, the outer diameter portion 111 is insulated from each iron core 22 by the first insulating tape 141. Furthermore, the outer diameter end of the outer diameter portion 111 is connected to the guide portion 52 of the housing 5. Thus, the first conductor 11 is electrically connected to the housing 5.

[0049] The plurality of intermediate portions 112 are rectangular conductive coatings applied to the plurality of surfaces 91 of the mold resin 9 that seal the side surfaces of two adjacent cores 22 among the plurality of cores 22, facing the rotor 3. A second insulating tape 142 and a third insulating tape 143 are provided between the two adjacent cores 22 and each intermediate portion 112, protruding from the surface 91 of the mold resin 9 that faces the rotor 3. Thus, each intermediate portion 112 is insulated from the two adjacent cores 22 by the second insulating tape 142 and the third insulating tape 143.

[0050] The inner diameter portion 113 is an annular conductive coating material applied to the surface 91 of the molded resin 9 facing the rotor 3, sealing the inner side surfaces of the annularly arranged plurality of cores 22. A fourth insulating tape 144, projecting from the surface 91 of the molded resin 9 facing the rotor 3, is provided between the inner diameter portion 113 and each core 22. Thus, the inner diameter portion 113 is insulated from each core 22 by the fourth insulating tape 144. Furthermore, the inner diameter end of the inner diameter portion 113 contacts an annular protrusion 251 that protrudes annularly from the surface 91 of the molded resin 9 facing the rotor 3, along the axial hole 25. Consequently, the annular protrusion 251 shields the inner diameter portion 113 from the axial hole 25. Therefore, during the coating process of the inner diameter portion 113, the conductive coating material can be prevented from flowing into the axial hole 25.

[0051] The conductive coating or the like that forms the outer diameter portion 111, the plurality of intermediate portions 112, and the inner diameter portion 113 is connected. Thus, each core 22 is surrounded by the conductive coating or the like that forms the outer diameter portion 111, the plurality of intermediate portions 112, and the inner diameter portion 113. Thus, an annular portion 114 of the conductive coating or the like is formed around each core 22, annularly surrounding each core 22. Thus, the first conductor 11 is a collection of the conductive coating or the like that forms the annular portion 114 surrounding each of the annularly arranged cores 22.

[0052] Furthermore, the first to fourth insulating tapes 141 to 144 form an annular insulating tape 14 surrounding each iron core 22 . Therefore, each iron core 22 is insulated from the first conductor 11 by the insulating tape 14 .

[0053] The notch 13 electrically cuts off the annular portion 114 surrounding the core 22. The notch 13 electrically cuts off the annular portion 114, thereby cutting off the current flowing along the annular portion 114 and preventing the generation of eddy current.

[0054] Specifically, notch 13 is an insulator that protrudes from surface 91 of molded resin 9, which faces rotor 3, and is connected to the insulating portions inside and outside annular portion 114. Notch 13 is connected to the insulating portions inside and outside annular portion 114, thereby electrically isolating annular portion 114. Conversely, if notch 13 is connected to a conductive member inside or outside annular portion 114, annular portion 114 is not electrically isolated. For example, if notch 13 is connected to guide portion 52 of housing 5, which is a conductive member outside annular portion 114, current flowing along annular portion 114 flows through guide portion 52 connected to notch 13 without being isolated.

[0055] The notch portion 13 of the axial gap rotating electrical machine 1 of this embodiment is connected to the fourth insulating tape 144 as the inner insulating portion of the annular portion 114 and is connected to the annular convex portion 251 as the outer insulating portion of the annular portion 114 .

[0056] In addition, the notch portion 13 of the axial gap rotating electrical machine 1 of the present embodiment is connected to the annular convex portion 251 as described above. Therefore, the inner diameter portion 113 is cut off by the notch portion 13 .

[0057] In addition, the axial gap rotating electric machine 1 of the present embodiment, like the axial gap rotating electric machine 100 of the comparative example, may deform the sealing surfaces 92 to 95 of the molded resin 9 that seals the side surfaces of the iron core 22 during long-term use and move away from the iron core 22, thereby generating gaps between the sealing surfaces 92 to 95 and the iron core 22.

[0058] Based on the long-term use of an axial gap rotating electric machine, the inventors have concluded that the gap tends to form more frequently at sealing surfaces 92 and 93 sealing the side surfaces of the iron core 22 in the circumferential direction of the stator 2, less frequently at sealing surfaces 93 and 94 sealing the side surfaces of the iron core 22 on the inner and outer diameter sides of the stator 2, and least frequently at sealing surface 94 sealing the side surfaces of the iron core 22 on the inner diameter side of the stator 2. Therefore, the axial gap rotating electric machine of the present invention includes a second conductor 12, such as a conductive coating applied to at least one of the inner and outer diameter sides of the stator 2 in the iron core 22 on the surface of the molded resin 9 facing the rotor 3, so as to electrically connect the first conductor 11 to the iron core 22.

[0059] In particular, in the axial gap type rotating electrical machine 1 of this embodiment, as Figure 5 As shown, the second conductor 12 is located on the inner diameter side of the stator 2 in the iron core 22 on the opposite surface 91 of the molded resin 9 facing the rotor 3, and electrically connects the inner diameter portion 222 on the inner diameter side of each annularly arranged iron core 22 to the inner diameter portion 113 of the first conductor 11.

[0060] In addition, the second conductor 12 may be Figure 5 As shown, the mold resin 9 is coated not only on the surface 91 facing the rotor 3 but also on the end surface 221 of each core 22 facing the rotor 3 and the inner diameter portion 113 of the first conductor 11 .

[0061] Alternatively, the second conductor 12 may be applied in a linear form on an end surface 221 of an iron core 22 formed by laminating a plurality of steel plates in the radial direction of the stator 2 , the end surface facing the rotor 3 , to electrically connect the plurality of steel plates.

[0062] In addition, the first conductor 11 and the second conductor 12 may be formed of the same conductive member.

[0063] Alternatively, the first conductor 11 and the second conductor 12 may be formed of different conductive materials. For example, the first conductor 11 may be formed of a conductive paint, and the second conductor 12 may be formed of a conductive tape having a conductive filler mixed in its adhesive layer. The reason for this is as follows.

[0064] The first conductor 11 is provided only on the surface 91 of the molded resin 9 facing the rotor 3, surrounds each iron core 22, and has a complex shape combining a circular arc and a rectangular shape with a notch 13. In contrast, the second conductor 12 is provided on three different parts: the surface 91 of the molded resin 9 facing the rotor 3, the end surface 221 of the iron core 22 facing the rotor 3, and the first conductor 11, and has a simple rectangular shape.

[0065] On the other hand, conductive paints and the like are in liquid form and harden after being applied, so as mentioned above, there is no need for a step of pre-processing into a shape that matches the installation location. In addition, even complex shapes can be easily handled. However, conductive paints and the like are liquid, so there are cases where the color or deformation occurs depending on the affinity of the material to which they are applied. Therefore, when applying conductive paints and the like to a surface, it is preferably applied to a surface formed of the same material. In addition, conductive paints and the like harden after being applied, so they adhere closely to the surface to which they are applied. Therefore, when the surface to which they are applied is broken, the conductive paints and the like are also likely to break. Therefore, it is suitable for the first conductor 11.

[0066] On the other hand, conductive tape is solid, making it difficult to easily adapt to complex shapes. However, it can be applied independently of the material being applied, preventing shading or deformation. Therefore, conductive tape can be applied to surfaces made of different materials. Furthermore, because the conductive tape is a solid material, it does not adhere closely to the surface being applied. Therefore, even if the applied surface breaks, the conductive tape is unlikely to break. Therefore, it is suitable for the second conductor 12.

[0067] [Effect]

[0068] In the axial gap rotating electrical machine 1 of this embodiment, the first conductor 11 is electrically connected to the case 5 . Therefore, the first conductor 11 can be grounded through the case 5 , thereby preventing the potential of the first conductor 11 from drifting and thus preventing shaft voltage from occurring.

[0069] Furthermore, each core 22 is electrically connected to the first conductor 11 via each second conductor 12. Therefore, each core 22 can be grounded via the first conductor 11 and the plurality of second conductors 12 through the housing 5, thereby preventing the potential of each core 22 from drifting and thus preventing shaft voltage from occurring.

[0070] In particular, the second conductor 12 of the axial gap rotating electric machine 1 of this embodiment is applied to the inner diameter side of the stator 2 within the iron core 22, on the surface 91 of the molded resin 9 facing the rotor 3. Specifically, the second conductor 12 is applied at a location where a gap is least likely to form between the molded resin 9, which seals the side surfaces of the iron core 22, and the side surfaces of the iron core 22 during long-term use of the axial gap rotating electric machine 1. Therefore, even with long-term use of the axial gap rotating electric machine 1, the second conductor 12 is unlikely to break, maintaining electrical connection between the iron core 22 and the first conductor 11. Consequently, the axial gap rotating electric machine 1 of this embodiment is less likely to cause electrical corrosion in the bearing 6 even during long-term use, preventing a reduction in bearing life.

[0071] Furthermore, the axial gap rotating electric machine 1 of this embodiment has notches 13 provided in each of the plurality of annular portions 114 of the first conductor 11. This allows the current flowing along each annular portion 114 to be interrupted. This suppresses eddy currents and prevents a decrease in the efficiency of the axial gap rotating electric machine 1.

[0072] Furthermore, each notch 13 is connected to the annular protrusion 251, which is the molded resin forming the opening edge of the axial center hole 25, thereby radially blocking the inner diameter portion 113 of the first conductor 11. This cutout 13 can thus block current flowing along the inner diameter portion 113. This can suppress eddy currents and prevent a decrease in the efficiency of the axial gap rotating electric machine 1.

[0073] Furthermore, each notch 13 is located on the inner diameter side of the stator core 21 within the iron core 22. This prevents the area of each notch 13 from increasing, suppressing a reduction in the area of the first conductor 11. Consequently, a reduction in shielding area can be suppressed. Furthermore, each notch 13 is located on the inner diameter side of the stator core 21 within the iron core 22, reducing the amount of work required to coat the first conductor 11 and improving production efficiency.

[0074] Furthermore, the first and second conductors 11 and 12 are made of conductive paint, etc. Therefore, there is no need to pre-process the first and second conductors 11 and 12 into shapes that match the locations where they are to be installed, thereby improving production efficiency.

[0075] Furthermore, the second conductor 12 is applied not only to the surface 91 of the molded resin 9 facing the rotor 3, but also to the end surfaces 221 of each iron core 22 facing the rotor 3, and to the inner diameter portion 113 of the first conductor 11. This increases the portion of the second conductor 12 that contacts each iron core 22 and the inner diameter portion 113 of the first conductor 11. Consequently, the reliability of the electrical connection between each iron core 22 and the inner diameter portion 113 of the first conductor 11 can be improved.

[0076] Furthermore, the first conductor 11 and the second conductor 12 can be formed of the same conductive member, thereby reducing manufacturing costs and improving work efficiency.

[0077] Alternatively, different conductive members may be used to form the first conductive member 11 and the second conductive member 12. This allows the use of conductive members that match the shape and location of the conductive member, thereby improving work efficiency and durability.

[0078] The second conductor 12 is preferably applied linearly to the end surface 221 of each core 22 facing the rotor 3. This prevents eddy currents from being generated in the second conductor 12 applied to the end surface 221 of each core 22 facing the rotor 3.

[0079] In particular, the second conductor 12 is preferably applied linearly to the end surface 221 of the iron core 22, which is formed by stacking multiple steel plates in the radial direction of the stator 2 and faces the rotor 3, thereby electrically connecting the multiple steel plates. This allows the individual steel plates constituting the iron core 22 to be grounded, reliably preventing the potential of the iron core 22 from drifting.

[0080] (Second embodiment)

[0081] Figure 6 Schematic diagram of a case 5 and a stator 2 of an axial gap type rotating electrical machine 20 according to a second embodiment of the present invention as viewed from the rotor 3 side.

[0082] The axial gap rotating electric machine 20 of this embodiment differs from the axial gap rotating electric machine 1 of the first embodiment in the arrangement of the second electrical conductor 15. Specifically, the axial gap rotating electric machine 20 of this embodiment includes the second electrical conductor 15, which is located on the outer diameter side of the stator 2 within the iron core 22 on the surface 91 of the molded resin 9 facing the rotor 3, and electrically connects the outer diameter portion 223 of each of the annularly arranged iron cores 22 to the outer diameter portion 111 of the first electrical conductor 11.

[0083] [Effect]

[0084] In the axial gap rotating electric machine 20 of this embodiment, the second conductor 15 is located on the outer diameter side of the stator 2 within the iron core 22, on the surface 91 of the molded resin 9 facing the rotor 3. Consequently, the grounding path of the iron core 22 is shorter than that of the axial gap rotating electric machine 1 of the first embodiment, and the resistance of the grounding path can be suppressed. Consequently, the potential difference between each iron core 22 and the case 5 can be reduced compared to the axial gap rotating electric machine 1 of the first embodiment, preventing the generation of shaft voltage.

[0085] Furthermore, the second electrical conductors 15 of the axial gap rotating electric machine 20 of this embodiment are located on the outer diameter side of the stator 2 within the iron core 22 on the surface 91 of the molded resin 9 facing the rotor 3. Therefore, compared to second electrical conductors located on both circumferential sides of the stator 2 within the iron core 22 on the surface 91 of the molded resin 9 facing the rotor 3, they are less likely to break, and the electrical connection between the iron core 22 and the first electrical conductors 11 can be maintained. Consequently, the axial gap rotating electric machine 20 of this embodiment is less likely to cause electrical corrosion in the bearings 6 even during long-term use, preventing a reduction in bearing life.

[0086] The second conductor 15 is preferably applied linearly to the end surface 221 of each core 22 facing the rotor 3. This prevents eddy currents from being generated in the second conductor 15 applied to the end surface 221 of each core 22 facing the rotor 3.

[0087] The second conductor 15 is preferably applied linearly to the end surface 221 of the iron core 22, which is formed by stacking multiple steel plates in the radial direction of the stator 2 and faces the rotor 3, thereby electrically connecting the multiple steel plates. This allows the individual steel plates constituting the iron core 22 to be grounded, reliably preventing the potential of the iron core 22 from drifting.

[0088] (Third embodiment)

[0089] Figure 7 Schematic diagram of a case 5 and a stator 2 of an axial gap type rotating electrical machine 30 according to a third embodiment of the present invention as viewed from the rotor 3 side.

[0090] The axial gap type rotating electrical machine 30 of this embodiment is as follows Figure 7 As shown, both the second electrical conductor 12 of the axial gap rotating electrical machine 1 of the first embodiment and the second electrical conductor 15 of the axial gap rotating electrical machine 20 of the second embodiment are included.

[0091] [Effect]

[0092] In the axial gap rotating electric machine 30 of this embodiment, the second conductor 12 is located on the inner diameter side of the stator 2 within the core 22, on the surface 91 of the molded resin 9 facing the rotor 3. Specifically, the second conductor 12 is applied at a location where a gap is least likely to form between the molded resin 9, which seals the core 22, and the core 22 during long-term use of the axial gap rotating electric machine 30. Therefore, even with long-term use of the axial gap rotating electric machine 1, the second conductor 12 is unlikely to break, maintaining electrical connection between the core 22 and the first conductor 11. Consequently, the axial gap rotating electric machine 30 of this embodiment is less likely to cause electrical corrosion in the bearing 6, even during long-term use, preventing a reduction in bearing life.

[0093] Furthermore, in the axial gap rotating electric machine 30 of this embodiment, the second conductor 15 is located on the outer diameter side of the stator 2 within the iron core 22 on the surface 91 of the molded resin 9 facing the rotor 3. Consequently, the grounding path of the iron core 22 is shorter than that of the axial gap rotating electric machine 1 of the first embodiment, and the resistance of the grounding path can be suppressed. Consequently, the potential difference between each iron core 22 and the case 5 can be reduced compared to the axial gap rotating electric machine 1 of the first embodiment, further preventing the generation of shaft voltage.

[0094] (Fourth embodiment)

[0095] Figure 8 Schematic diagram of a case 5 and a stator 2 of an axial gap type rotating electrical machine 40 according to a fourth embodiment of the present invention as viewed from the rotor 3 side.

[0096] The axial gap rotating motor 40 of this embodiment differs from the axial gap rotating motor 1 of the first embodiment in that a fitting portion 522 is provided on the guide portion 52, and the first conductor 11 is applied to a predetermined area 16 centered around the fitting portion 522 between the guide portion 52 and the surface of the molded resin 9 facing the rotor 3.

[0097] exist Figure 9 FIG. 1 is an enlarged perspective view of the fitting portion 522 of the axial gap type rotating electrical machine 1 according to the first embodiment of the present invention. Figure 9 As shown, the fitting portion 522 is a recessed portion that is recessed from the inner peripheral wall 523 of the guide portion 52 toward the outer diameter of the cylindrical portion 51. The fitting portion 522 has a portion where the width of the gap between the fitting portion 522 and the cylindrical portion 51 is wider on the outer diameter side than on the inner diameter side in the circumferential direction of the cylindrical portion 51. Thus, the fitting portion 522 has a narrowed shape.

[0098] Figure 8 The predetermined region 16 shown in FIG. 1 is a region where the molded resin 9 filled in the fitting portion 522 and solidified can prevent the molded resin 9 that has come into contact with the inner peripheral wall of the guide portion 52 from leaving the inner peripheral wall of the guide portion 52 .

[0099] The range of the predetermined region 16 varies depending on the shape of the fitting portion 522 and the material of the molded resin 9. The first conductor 11 is preferably provided throughout the predetermined region 16, but may be provided in a portion of the predetermined region 16 including the junction between the guide portion 52 and the molded resin 9.

[0100] [Effect]

[0101] The molded resin 9 filled and solidified in the interlocking portion 522 will engage with the narrowed portion of the interlocking portion 522 even if it shrinks in the radial direction of the stator 2 due to aging, etc., and a force is applied to separate from the inner circumferential wall of the guide portion 52, thereby preventing it from leaving the inner circumferential wall of the guide portion 52.

[0102] Furthermore, since the first conductor 11 is applied to the predetermined region 16, the electrical connection between the iron core 22 and the housing 5 of the axial gap rotating electric machine 1 can be maintained even after long-term use. This continuously suppresses electrical corrosion of the bearing 6, and provides an axial gap rotating electric machine 40 with high reliability against bearing electrical corrosion.

[0103] (Fifth embodiment)

[0104] Figure 10 It is an axial cross-sectional view of a casing and a stator of an axial gap rotating electrical machine 50 according to a fifth embodiment of the present invention.

[0105] The axial gap rotating electric machine 50 of this embodiment differs from the axial gap rotating electric machine 1 of the first embodiment in that the core 22 and the coil 24 are insulated by an insulator 26 such as an insulating sheet, and the flange portion 232 of the bobbin 23 is not provided between the first conductor 11 and the coil 24 .

[0106] Specifically, in the axial gap rotating electric machine 1 of the first embodiment, the core 22 and coil 24 are insulated by a bobbin 23 having a cylindrical portion 231 surrounding the core 22 and flange portions 232 extending circumferentially from near both end openings of the cylindrical portion 231 along the shape of the opening edges to restrict the winding width of the coil 24. In contrast, the axial gap rotating electric machine 50 of the present embodiment insulates the core 22 and coil 24 using an insulator 26 (e.g., an insulating sheet) having only the cylindrical portion 231 and no flange portions 232. Therefore, in the axial gap rotating electric machine 50 of the present embodiment, the molded resin 9 located between the first conductor 11 and the coil 24 is in contact with both the first conductor 11 and the coil 24.

[0107] [Effect]

[0108] In the axial gap rotating electrical machine 50 of the present embodiment, the insulator 26 does not have the flange portion 232. Therefore, the bobbin 23 can be easily manufactured, and the cost can be suppressed.

[0109] (Sixth embodiment)

[0110] Figure 11 Schematic diagram of the housing 5 and the stator 2 of the axial gap type rotating electrical machine 60 according to the sixth embodiment of the present invention as viewed from the rotor 3 side. Figure 12 It is an axial cross-sectional view of a casing and a stator of an axial gap type rotating electrical machine according to a sixth embodiment of the present invention.

[0111] The axial gap rotating machine 60 of this embodiment differs from the axial gap rotating machine 1 of the first embodiment in that the conductor 10 is provided not on the molded resin 9 but on the facing surface 233 of the flange portion 232 of the bobbin 23 that faces the rotor 3 .

[0112] That is, the axial gap type rotating electric machine 60 of this embodiment includes a plurality of stator cores 21 on which coils 24 are wound via a winding frame 23 covering the side surface of the iron core 22; a stator 2 formed by arranging the plurality of stator cores 21 in a ring shape; a rotor 3 facing the stator 2 across an air gap; a housing 5 covering the stator 2; a flange portion 232 provided at an end portion of the winding frame 23 and having an opposing surface 233 opposing the rotor 3; an annular first conductor 11 electrically connected to the housing 5, which is provided on the opposing surface 233 in a manner surrounding the periphery of the iron core 22 and has a notch portion 13 in a portion of the periphery of the iron core 22; and a second conductor 12 provided on the opposing surface 233 on the inner diameter side of the stator 2 in the iron core 22 so as to electrically connect the first conductor 11 to the iron core 22.

[0113] use Figure 11 and Figure 12 The first conductor 11 of this embodiment is described in detail. The first conductor 11 is formed by applying a conductive coating to a surface 233 of a flange 232 of a bobbin 23 facing the rotor 3 and includes an annular portion 114 surrounding the core 22 and a notch 13 .

[0114] The annular portion 114 is connected to the guide portion 52 of the housing 5. Thus, the first electrical conductor 11 is electrically connected to the housing 5. Furthermore, an insulating tape 14 is formed between the annular portion 114 and the iron core 22. The insulating tape 14 is an insulator that protrudes annularly from the surface 233 of the flange 232 facing the rotor 3 along the opening of the barrel 231 of the bobbin 23. Thus, each iron core 22 is insulated from the first electrical conductor 11 by the insulating tape 14.

[0115] The notch 13 electrically cuts off the annular portion 114 surrounding the core 22. The notch 13 electrically cuts off the annular portion 114, thereby cutting off the current flowing along the annular portion 114 and preventing the generation of eddy current.

[0116] Specifically, the notch portion 13 is an insulator that protrudes from a surface 233 of the flange portion 232 that faces the rotor 3 and is connected to the insulating tape 14 and the outer edge of the flange portion 232 .

[0117] In addition, the axial gap rotating electric machine 60 of this embodiment, like the axial gap rotating electric machine 100 of the comparative example, may have the problem of the inner side surfaces 234 to 237 of the winding frame 23 connected to the side surfaces of the iron core 22 being deformed and separated from the iron core 22 during long-term use, thereby generating gaps between the inner side surfaces 234 to 237 and the side surfaces of the iron core 22.

[0118] The inventors have concluded that the gaps generated in the axial gap type rotating electric machine after long-term use tend to be more common at the inner side surfaces 234 and 235 connected to the side surfaces of the iron core 22 in the circumferential direction of the stator 2, and least common at the inner side surface 237 connected to the side surfaces of the iron core 22 on the inner diameter side of the stator 2, similar to the first embodiment. Figure 11 As shown, the second conductor 12 is located on the inner diameter side of the stator 2 in the core 22 on the opposing surface 233 of the flange portion 232 facing the rotor 3 , electrically connecting the inner diameter portion 222 of the core 22 to the inner diameter portion 113 of the first conductor 11 .

[0119] In addition, the second conductor 12 may be Figure 11 As shown, the coating is applied not only to the surface 233 of the flange portion 232 facing the rotor 3 , but also to the end surface 221 of each core 22 facing the rotor 3 and the inner diameter portion 113 of the first conductor 11 .

[0120] Alternatively, the first and second conductors 11, 12 can be formed from the same conductor. Furthermore, the first conductor 11 is provided only on the surface 233 of the flange 232 of the bobbin 23 that faces the rotor 3, surrounds each core 22, and has a notch 13, forming a shape that is a combination of a circular arc and a rectangle. In contrast, the second conductor 12 is provided on three different parts: the surface 233 of the flange 232 of the bobbin 23 that faces the rotor 3, the end surface 221 of the core 22 that faces the rotor 3, and the first conductor 11, resulting in a simple rectangular shape. Therefore, the first and second conductors 11, 12 can also be formed from different conductors. For example, conductive paint can be used for the first conductor 11, and conductive tape can be used for the second conductor 12.

[0121] [Effect]

[0122] In the axial gap rotating electrical machine 60 of this embodiment, the first conductor 11 is electrically connected to the case 5 . Therefore, the first conductor 11 can be grounded through the case 5 , preventing the potential of the first conductor 11 from drifting and thus preventing shaft voltage from occurring.

[0123] The core 22 is electrically connected to the first conductor 11 via the second conductor 12. Therefore, the core 22 can be grounded via the first conductor 11 and the plurality of second conductors 12 through the housing 5, thereby preventing the potential of the core 22 from drifting and thus preventing shaft voltage from occurring.

[0124] In particular, the second conductor 12 of the axial gap rotating electric machine 60 of this embodiment is applied to the inner diameter side of the stator 2 within the core 22, on the surface 233 of the flange portion 232 of the bobbin 23 that faces the rotor 3. Specifically, the second conductor 12 is applied at a location where a gap is least likely to form between the inner surface of the bobbin 23 connected to the core 22 and the side surface of the core 22 during long-term use of the axial gap rotating electric machine 60. Therefore, even with long-term use of the axial gap rotating electric machine 60, the second conductor 12 is unlikely to break, maintaining electrical connection between the core 22 and the first conductor 11. Consequently, the axial gap rotating electric machine 60 of this embodiment is less likely to cause electrical corrosion in the bearing 6, even with long-term use, preventing a reduction in bearing life.

[0125] Furthermore, the axial gap rotating machine 60 of this embodiment has the notch 13 provided in the first conductor 11. This can block the current flowing along the annular portion 114. This can suppress eddy currents and prevent a decrease in the efficiency of the axial gap rotating machine 60.

[0126] Furthermore, the second conductor 12 is applied not only to the surface 233 of the flange portion 232 of the bobbin 23 that faces the rotor 3, but also to the end surface 221 of each iron core 22 that faces the rotor 3, and to the inner diameter portion 113 of the first conductor 11. This ensures a strong electrical connection between each iron core 22 and the inner diameter portion 113 of the first conductor 11.

[0127] Furthermore, the first conductor 11 and the second conductor 12 can be formed of the same conductor, thereby improving working efficiency.

[0128] Alternatively, the first conductor 11 and the second conductor 12 may be formed of different conductors using materials that match the locations where they are disposed. This can improve work efficiency and durability.

[0129] The second conductor 12 is preferably applied linearly to the end surface 221 of each core 22 facing the rotor 3. This prevents eddy currents from being generated in the second conductor 12 applied to the end surface 221 of each core 22 facing the rotor 3.

[0130] In particular, the second conductor 12 is preferably applied linearly to the end surface 221 of the iron core 22, which is formed by stacking multiple steel plates in the radial direction of the stator 2 and faces the rotor 3, thereby electrically connecting the multiple steel plates. This allows the individual steel plates constituting the iron core 22 to be grounded, reliably preventing the potential of the iron core 22 from drifting.

[0131] Furthermore, the present invention is not limited to the above-described embodiments and includes various variations. For example, the above-described embodiments are described in detail to facilitate understanding of the present invention and are not limited to having all the structures described. Furthermore, a portion of the structure of a particular embodiment can be replaced with a structure of another embodiment, and a structure of another embodiment can be added to a structure of a particular embodiment. Furthermore, other structures can be added, deleted, or substituted for a portion of the structure of each embodiment.

[0132] Alternatively, the present invention may be implemented as follows. The axial gap rotating electrical machine may be a single-rotor type. Furthermore, the iron core 22 may be formed from magnetic iron powder. An example of 12 slots is shown, but another number of slots is also possible. Furthermore, other materials, such as composite resins, films, or inorganic fibers, may be provided on the conductor 10 to improve the adhesiveness, tightness, and heat resistance of the conductor 10. Furthermore, the surface to which the conductive coating is applied may be roughened to allow for a bonding effect.

[0133] Description of Reference Numerals

[0134] 1, 20, 30, 40, 50, 60, 100…axial gap type rotating electrical machine, 2…stator, 3…rotor, 5…housing, 6…bearing, 9…molding resin, 10…conductor, 11…first conductor, 12, 15…second conductor, 13…notch, 21…stator core, 22…iron core, 23…bobbin, 24…coil, 91, 233, 521…opposing surfaces.

Claims

1. An axial gap type rotating electrical machine, characterized in that: include: A plurality of stator cores having coils wound around iron cores; a stator formed by arranging the plurality of stator cores in a ring shape; a rotor facing the stator across an air gap; a housing covering the stator; a mold resin sealing a side surface of the core, the core having an opposing surface opposed to the rotor; a first annular conductor electrically connected to the housing, the first conductor being provided on the opposing surface so as to surround the iron core and having a notch formed in a portion of the periphery of the iron core; and A second conductor is provided to electrically connect the first conductor and the iron core, and is located on at least one of the inner diameter side and the outer diameter side of the stator of the iron core on the opposing surface. The first conductor and the second conductor are conductive paint or conductive adhesive, The second electrical conductor is coated on the iron core and the first electrical conductor.

2. The axial gap rotating electrical machine according to claim 1, wherein: The stator has a through hole in the center. The notch portion is connected to the mold resin forming the opening edge of the through hole.

3. The axial gap rotating electrical machine according to claim 2, wherein: The notch portion is located on the inner diameter side of the stator core of the iron core.

4. The axial gap rotating electrical machine according to claim 1, wherein: The housing is provided with a fitting portion that can be fitted with the molded resin.

5. The axial gap rotating electrical machine according to claim 1, wherein: Of the molded resin, a portion of the molded resin located between the first conductor and the coil is in contact with the first conductor and the coil.

6. The axial gap rotating electrical machine according to claim 1, wherein: The first conductor and the second conductor are formed of the same conductive material.

7. The axial gap rotating electrical machine according to claim 1, wherein: The first conductor and the second conductor are formed of different conductive materials.

8. The axial gap rotating electrical machine according to claim 1, wherein: The iron core includes a plurality of steel plates stacked in a radial direction of the stator. The second conductor is provided in a linear shape on an end surface of the iron core facing the rotor, and electrically connects the plurality of steel plates.

9. An axial gap type rotating electrical machine, characterized in that: include: A plurality of stator cores on which coils are wound via a bobbin covering the side surfaces of the core; a stator formed by arranging the plurality of stator cores in a ring shape; a rotor facing the stator across an air gap; a housing covering the stator; a flange portion provided at an end portion of the bobbin and having an opposing surface opposed to the rotor; a first annular conductor electrically connected to the housing, the first conductor being provided on the opposing surface so as to surround the iron core and having a notch formed in a portion of the periphery of the iron core; and A second conductor is provided to electrically connect the first conductor and the iron core, and is located on the inner diameter side of the stator of the iron core on the opposing surface. The first conductor and the second conductor are conductive paint or conductive adhesive, The second electrical conductor is coated on the iron core and the first electrical conductor.

10. The axial gap rotating electrical machine according to claim 9, wherein: The first conductor and the second conductor are formed of the same conductor.

11. The axial gap rotating electrical machine according to claim 9, wherein: The first conductor and the second conductor are formed of different conductors.

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