Rotary machine

Abstract

To provide a rotary machine that suppresses output reduction due to temperature rise while reducing concerns about electrolytic corrosion due to increased shaft voltage.SOLUTION: A rotary machine includes a stator, a rotor 40, a rotating shaft 50, and an insulating layer. The rotor 40 is arranged so as to provide an axial gap with respect to the stator. Specific examples of the insulating layer include an adhesive 81 and a washer 82. The adhesive 81 and the washer 82 are arranged at the connection portion between the rotor 40 and the rotating shaft 50, and electrically insulate the rotor 40 and the rotating shaft 50 from each other.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The disclosure in this specification relates to an axial gap type rotating machine. [Background technology]

[0002] Patent Document 1 describes an axial gap type rotating machine in which a rotor is disposed so that a gap is provided in the direction of the rotating shaft relative to the stator. In this type of rotating machine, a voltage path is formed in the order of the stator, rotor, and rotating shaft, and the electric potential (shaft voltage) of the rotating shaft may become high. If the shaft voltage becomes high, there is a concern that the bearing supporting the rotating shaft may become electrolytically corroded. Therefore, in the rotating machine, a ring-shaped ground plate (conductive member) is disposed between the stator and rotor. This prevents a voltage path from being formed between the stator and rotor, thereby suppressing electrolytic corrosion of the bearing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-017915 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned structure, the ground plate is located in a position where it is greatly affected by the rotating magnetic field generated by the stator. This causes eddy currents in the ground plate, which generates heat. As a result, this hinders the cooling of the rotating machine, leading to a decrease in the output of the rotating machine.

[0005] One disclosed object is to provide a rotating machine that suppresses a decrease in output due to an increase in temperature, while reducing concerns about electrolytic corrosion due to an increase in shaft voltage. [Means for solving the problem]

[0006] In order to achieve the above object, a rotating machine according to one aspect of the present disclosure includes: A stator (30) that generates a rotating magnetic field; A rotor (40) arranged to provide an axial gap with respect to the stator; A rotating shaft (50) connected to the rotor; and an insulating layer (81, 82, 83, 84, 85, 86, 94, 70i) that is disposed at a connection portion between the rotor and the rotating shaft and provides electrical insulation between the rotor and the rotating shaft.

[0007] According to the rotating machine disclosed herein, the insulating layer can suppress the formation of a voltage path between the rotor and the rotating shaft. This reduces the risk of electrolytic corrosion due to an increase in shaft voltage. In addition, it is no longer necessary to place a ground plate between the stator and the rotor, which can suppress a decrease in output of the rotating machine due to an increase in temperature.

[0008] The reference numbers in parentheses merely indicate an example of a corresponding relationship with a specific configuration in an embodiment described later, and do not limit the technical scope in any way. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a rotating machine according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Diagram 3] FIG. 2 is an enlarged view of a bolt portion in FIG. [Figure 4] FIG. 2 is an electric circuit diagram illustrating a voltage path of the rotating machine shown in FIG. 1. [Diagram 5] FIG. 11 is an enlarged view of a bolt portion in the second embodiment. [Figure 6] FIG. 13 is an enlarged view of a bolt portion in the third embodiment. [Figure 7] FIG. 13 is an enlarged view of a bolt portion in the fourth embodiment. [Figure 8] FIG. 11 is a cross-sectional view of a rotating machine according to a fifth embodiment. [Figure 9] 9 is a cross-sectional view taken along line IX-IX of FIG. 8. [Figure 10] FIG. 9 is an enlarged view of a bolt portion in FIG. 8. [Figure 11] FIG. 9 is an enlarged view of a knock pin portion in FIG. 8. [Figure 12] FIG. 13 is an enlarged view of a bolt portion in the sixth embodiment. [Figure 13] FIG. 13 is an enlarged view of a knock pin portion in the sixth embodiment. [Figure 14] FIG. 13 is a cross-sectional view of a rotating machine according to a seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a number of embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals may be used to designate parts corresponding to matters described in the preceding embodiment, and duplicated descriptions may be omitted. In each embodiment, when only a part of the configuration is described, other embodiments described previously may be applied to other parts of the configuration. In addition to combinations of parts that are specifically indicated as being possible in each embodiment, it is also possible to partially combine embodiments even if not indicated, as long as there is no particular problem with the combination.

[0011] (First embodiment) The rotating machine according to this embodiment functions as a power source for rotating the propeller of an aircraft and is mounted on the aircraft. The aircraft is a vertical take-off and landing type eVTOL. The propeller may be a propeller that exerts flight thrust during vertical take-off and landing or hovering, or may be a propeller that exerts flight thrust during cruising by horizontal flight.

[0012] 1 is a motor that is rotationally driven by being supplied with three-phase AC power. The rotating machine 10 includes a housing 20, a stator 30, a rotor 40, a rotating shaft 50, bearings 60, and the like.

[0013] The housing 20 is a metal case that accommodates the stator 30 and the rotor 40. A pair of bearings 60 are attached to the housing 20. The bearings 60 hold the rotating shaft 50 in the housing 20 in a rotatable state.

[0014] The stator 30 has a stator core 31 and a winding 32. The stator core 31 is configured by stacking a plurality of electromagnetic steel sheets in the direction of the rotation axis. The direction of the rotation axis refers to the direction along the rotation center line C of the rotation axis 50. The winding 32 is wound around the stator core 31. The winding 32 is configured by star-connecting or delta-connecting a U-phase coil, a V-phase coil, and a W-phase coil. The power supply to each phase is turned on and off by a control device (not shown). A magnetic field generated by the power supply to the winding 32 is emitted to the outside of the stator 30 through the stator core 31. The magnetic field thus emitted rotates by switching the power supply to each phase coil on and off. In this manner, the stator 30 generates a rotating magnetic field.

[0015] The stator 30 is formed in a cylindrical shape surrounding the rotating shaft 50. The outer peripheral surface of the stator 30 and the inner peripheral surface of the housing 20 are in close contact with each other by resin 33. Metallic heat dissipation fins 21 are attached to the outer peripheral surface of the housing 20. The heat dissipation fins 21 are in a plate shape that expands in the rotation axis direction and the rotation radial direction. The heat dissipation fins 21 are provided in at least a range in the rotation axis direction where the windings 32 are provided. A plurality of heat dissipation fins 21 are provided in a line in the circumferential direction. An air-cooling fan (not shown) is provided on one axial end side of the rotating machine 10. The air-cooling fan causes cooling air to flow in the rotation axis direction along the outer peripheral surface of the housing 20. This cooling air and the heat dissipation fins 21 exchange heat.

[0016] The windings 32 generate heat when electricity is applied. This heat increases the temperature of the stator 30, and in turn increases the temperatures of the rotor 40 and the rotating shaft 50. Such an increase in temperature of the rotating machine 10 leads to a decrease in rotation output. In particular, an increase in the electrical resistance of the windings 32 leads to a decrease in rotation output. Therefore, in this embodiment, the windings 32 and the housing 20 are brought into close contact with each other using the resin 33, so that the heat of the windings 32 is transferred to the stator 30 and the heat of the stator 30 is dissipated from the heat dissipation fins 21. This suppresses the temperature increase of the rotating machine 10.

[0017] The rotor 40 is disposed so as to provide an axial gap with respect to the stator 30. In this embodiment, the rotor 40 is disposed on both one side and the other side in the rotation axis direction with respect to the stator 30. The rotor 40 has a plurality of magnets 41 and a rotor main body 42 made of metal.

[0018] 2, the magnets 41 are arranged at equal intervals in the circumferential direction of rotation. The surfaces of the magnets 41 that face the stator 30 are exposed from the rotor main body 42. The axial gap described above is formed between the exposed surfaces of the magnets 41 and the stator core 31.

[0019] The rotor body 42 is disk-shaped and holds the magnet 41. A shaft hole 42a through which the rotating shaft 50 is inserted is formed in the center of the rotor body 42. An air gap 42g is formed between the inner peripheral surface of the shaft hole 42a and the outer peripheral surface of the rotating shaft 50 that faces the inner peripheral surface. A plurality of through holes 42b through which the bolts 70 are inserted are formed in the rotor body 42 around the shaft hole 42a. The plurality of through holes 42b are formed at equal intervals in the circumferential direction.

[0020] As shown in FIG. 3, adhesive 81 is filled between bolt 70 and through hole 42b. This adhesive 81 is also filled between head 71 of bolt 70 and rotor body 42. While bolt 70 is made of metal, adhesive 81 is made of an electrically insulating material. Bolt 70 is a hexagonal bolt with head 71 having a hexagonal shape. A portion of neck portion 72 that is inserted into through hole 42b is not threaded, and thread 72a is formed at the tip. In other words, adhesive 81 is filled between the outer peripheral surface of the portion of neck portion 72 where thread 72a is not formed and the inner peripheral surface of through hole 42b.

[0021] The rotating shaft 50 is made of metal and has a shaft body portion 51 and a fastening portion 52. A part of the shaft body portion 51 is inserted into the shaft hole 42a. A part of the shaft body portion 51 is supported by a bearing 60. The fastening portion 52 extends radially from the shaft body portion 51 and faces the rotor body portion 42. A plurality of screw holes 52a are formed in the fastening portion 52 for fastening with bolts 70. By fastening with the bolts in this manner, the rotating shaft 50 is connected to the two rotors 40 and rotates integrally with the rotors 40.

[0022] A washer 82 is fitted onto the bolt 70. The washer 82 is made of an electrically insulating material, for example, resin. The washer 82 is sandwiched between the rotor body 42 and the fastening portion 52. The adhesive 81 and the washer 82 are disposed at the connection portion between the rotor 40 and the rotating shaft 50, and function as an insulating layer that electrically insulates between the rotor 40 and the rotating shaft 50.

[0023] As shown in FIG. 4, in the rotating machine 10 according to this embodiment, stray capacitances are formed at a plurality of locations, and these stray capacitances form a voltage path related to the AC voltage. The main stray capacitances are described below. A stray capacitance C1 is formed between the winding 32 and the stator core 31. A stray capacitance C2 is formed between the stator core 31 and the rotor body 42. A stray capacitance C3 is formed between the rotor body 42 and the rotating shaft 50. A stray capacitance C4 is formed between the rotating shaft 50 and the bearing 60. The bearing 60 has the same potential as the housing 20, which is grounded. Due to the above-mentioned stray capacitances C1, C2, C3, and C4 forming a series circuit, when the inverter voltage Vcom is applied to the winding 32, the potential (shaft voltage) of the rotating shaft 50 becomes higher than the ground voltage.

[0024] If, contrary to this embodiment, a material having no electrical insulation properties were used for the adhesive 81 and the washer 82, the rotor body 42 and the rotating shaft 50 would be electrically shorted. This would cause the shaft voltage to become even higher. In contrast, in this embodiment, a stray capacitance C3 is formed by the insulating layer between the rotor body 42 and the rotating shaft 50. As a result, the shaft voltage is reduced.

[0025] As described above, according to this embodiment, the connection portion between the rotor 40 and the rotating shaft 50 includes an insulating layer that electrically insulates. Specifically, a structure is adopted in which the rotor 40 and the rotating shaft 50 are connected by the bolt 70. The washer 82 and adhesive 81, which have electrical insulation properties, prevent the rotor body 42 and the fastening portion 52 from becoming the same potential via the bolt 70. In other words, the bolt 70 fastened to the rotating shaft 50 has the same potential as the rotating shaft 50, but the bolt 70 is electrically insulated from the rotor 40 by the adhesive 81. The rotor body 42 is pressed against the fastening portion 52 by the fastening force of the bolt 70, but is pressed via the washer 82, which has electrical insulation properties, so that the rotor body 42 is connected to the fastening portion 52 while ensuring electrical insulation between the rotor body 42 and the fastening portion 52. Therefore, as described in FIG. 4, the shaft voltage can be reduced, and concerns about electrolytic corrosion of the bearing 60 can be reduced.

[0026] Moreover, the insulating layer according to this embodiment makes it unnecessary to place a ground plate between the stator 30 and the rotor 40. This makes it possible to prevent the ground plate from increasing in temperature due to the influence of the rotating field magnet, thereby promoting the temperature rise of the rotating machine 10. In other words, the insulating layer according to this embodiment can reduce concerns about electrical corrosion of the bearing 60 due to an increase in shaft voltage while suppressing a decrease in the output of the rotating machine 10 due to a temperature rise.

[0027] Furthermore, in this embodiment, an adhesive 81 is provided between the through hole 42b and the bolt 70. The adhesive 81 functions as an insulating layer between the rotor 40 and the rotating shaft 50. Therefore, the insulating layer can be provided by a simple task of applying the adhesive 81.

[0028] Furthermore, in this embodiment, an air gap 42g is formed between the inner peripheral surface of the shaft hole 42a of the rotor 40 and the outer peripheral surface of the rotating shaft 50 facing the inner peripheral surface. Therefore, by setting the air gap 42g to be sufficiently large, it is possible to easily reduce the stray capacitance formed between the inner peripheral surface of the rotor 40 and the outer peripheral surface of the rotating shaft 50. Therefore, it is possible to easily suppress the voltage path formed between the rotor 40 and the rotating shaft 50. The size of the air gap 42g is set so that the stray capacitance formed between the inner peripheral surface of the rotor 40 and the outer peripheral surface of the rotating shaft 50 is smaller than the stray capacitance C3 formed by the insulating layer related to the adhesive 81 and the washer 82.

[0029] Second embodiment In the present embodiment shown in FIG. 5, a mesh sheet 83 made of a fiber material is added to the insulating layer according to the first embodiment. For example, the mesh sheet 83 is a flexible sheet formed by weaving electrically insulating fibers into a lattice pattern. The tubular mesh sheet 83 is fitted into the neck portion 72 of the bolt 70 and disposed in the through hole 42b. That is, the mesh sheet 83 is located between the head portion 71 and the rotor body portion 42, and between the neck portion 72 and the rotor body portion 42. In other words, the mesh sheet 83 is embedded in the adhesive 81.

[0030] The mesh sheet 83 functions as a spacer that maintains a gap between the outer peripheral surface of the neck portion 72 and the inner peripheral surface of the through hole 42b. This prevents the neck portion 72 from contacting the inner peripheral surface of the through hole 42b even if the bolt 70 is positioned radially offset in the through hole 42b before the adhesive 81 hardens. As a result, the radial thickness of the adhesive 81 after hardening can be ensured, and a short circuit between the bolt 70 and the rotor body 42 can be avoided, ensuring the stray capacitance C3.

[0031] Furthermore, the mesh sheet 83 functions as a spacer that maintains a gap between the head 71 of the bolt 70 and the rotor body 42. This prevents the head 71 from contacting the rotor body 42 even if the bolt 70 is positioned offset in the axial direction within the through hole 42b before the adhesive 81 hardens. As a result, the axial thickness of the adhesive 81 after hardening can be ensured, preventing a short circuit between the bolt 70 and the rotor body 42 and ensuring the stray capacitance C3.

[0032] As described above, according to this embodiment, the mesh sheet 83 is provided to maintain a gap between the inner circumferential surface of the through hole 42b and the outer circumferential surface of the bolt 70. This mesh sheet 83 has electrical insulation properties so as to function as an insulating layer. Therefore, it is possible to improve the reliability of avoiding a short circuit between the bolt 70 and the rotor main body 42.

[0033] Third embodiment 6, a collar 84 is disposed in the through hole 42b. For example, the collar 84 is made of a metal (e.g., aluminum) that is lower in hardness than the bolt 70. The cylindrical collar 84 is fitted into the neck portion 72 of the bolt 70, and is disposed in the through hole 42b. In other words, the collar 84 is located between the head 71 and the rotor main body 42, and between the neck portion 72 and the rotor main body 42.

[0034] The adhesive 81 is provided between the collar 84 and the rotor body 42. Specifically, the adhesive 81 is provided between the outer peripheral surface of the collar 84 and the inner peripheral surface of the through hole 42b. In addition, the adhesive 81 is provided between the flange portion 84a of the collar 84 and the rotor body 42. The bolt 70 connects the collar 84 and the fastening portion 52. The rotor body 42 is connected to the collar 84 by the adhesive 81.

[0035] The washer 82 is disposed between the collar 84 and the fastening portion 52, and electrically insulates the collar 84 from the fastening portion 52. The adhesive 81 electrically insulates the collar 84 from the rotor main body 42. In other words, the collar 84, which has the same potential as the rotating shaft 50 and the bolt 70, is electrically insulated from the rotor 40 by the adhesive 81. The collar 84 is not limited to being made of metal, and may be made of resin. In that case, the collar 84 also functions as an insulating layer.

[0036] As described above, according to this embodiment, the fastening force of the bolt 70 is not applied to the rotor 40. Therefore, damage to the rotor 40 due to the fastening force can be avoided. In particular, when a resin material reinforced with carbon fiber (e.g., CFRP) is used as the material for the rotor 40, the rotor 40 is more likely to be damaged than when it is made of metal. Therefore, when CFRP is used for the rotor 40, the effect of the collar 84 according to this embodiment is preferably exhibited.

[0037] (Fourth embodiment) In the present embodiment shown in Fig. 7, the bolt 70 according to the first embodiment is replaced with an insulating bolt 70i. The insulating bolt 70i has electrical insulation properties so as to function as an insulating layer. Specific examples of the material of the insulating bolt 70i include resins such as fluororesin and MC Nylon (registered trademark).

[0038] In this embodiment, the adhesive 81 according to the first embodiment is eliminated, and the insulating bolt 70i and the washer 82 function as an insulating layer between the rotating shaft 50 and the rotor 40. This embodiment also achieves the same effects as the first embodiment. In particular, since the adhesive 81 according to the first embodiment, which functions as an insulating layer, can be eliminated, the insulating layer can be realized with a simple configuration.

[0039] Fifth embodiment In this embodiment shown in FIG. 8, a transmission plate 90 and knock pins 91 are added to the rotating machine 10 according to the first embodiment. As shown in FIG. 9, the transmission plate 90 is disk-shaped and has a shaft hole 90a in the center. The shaft main body 51 is inserted into the shaft hole 90a. The transmission plate 90 is disposed between the rotor main body 42 and the fastening portion 52. The knock pins 91 are disposed at equal intervals in the circumferential direction. The knock pins 91 are disposed alternately with the bolts 70 in the circumferential direction.

[0040] 10, a through hole 90c is formed in a portion of the transmission plate 90 facing the through hole 42b. The neck portion 72 of the bolt 70 is inserted into the through hole 90c. As in the through hole 42b, the adhesive 81 is filled between the through hole 90c and the bolt 70.

[0041] Although not shown in Fig. 8, a boss 92 extending toward the washer 82 is formed in the portion of the transmission plate 90 where the through hole 90c is formed. The washer 82 is interposed between the boss 92 and the fastening portion 52. An insulating film 94 having electrical insulation properties is applied to the surface of the transmission plate 90. The insulating film 94 is applied to at least the portion facing the rotor body 42.

[0042] The adhesive 81, insulating film 94, and washer 82 are disposed at the connection portion between the rotor 40 and the rotating shaft 50, and function as an insulating layer that electrically insulates the rotor 40 and the rotating shaft 50. In detail, the bolt 70 has the same potential as the rotating shaft 50, and the bolt 70 and the rotor 40 are insulated by the insulating layer. The transmission plate 90 is clamped between the rotor body portion 42 and the fastening portion 52 by the fastening force of the bolt 70.

[0043] 11, a first insertion hole 90b into which one end of a knock pin 91 fits is formed in a plate surface (one plate surface) of the transmission plate 90 facing the fastening portion 52. The other end of the knock pin 91 fits into a second insertion hole 52b formed in the fastening portion 52. A boss 93 extending toward the fastening portion 52 is formed in the portion of the transmission plate 90 where the first insertion hole 90b is formed. The plate surface (the other plate surface) of the transmission plate 90 facing the rotor main body 42 is in surface contact with the rotor main body 42 with an insulating film 94 interposed therebetween.

[0044] The first insertion hole 90b has a recessed shape that does not allow the transmission plate 90 to pass therethrough. The second insertion hole 52b has a recessed shape that does not allow the fastening portion 52 to pass therethrough. It is preferable that the knock pin 91 is fitted into the first insertion hole 90b and the second insertion hole 52b in a state of interference fit or intermediate fit. The above fit may be a loose fit.

[0045] The rotational torque of the rotor 40 is transmitted to the rotating shaft 50 via the transmission plate 90 and the multiple knock pins 91. In the first embodiment, the bolt 70 transmits all of the rotational torque of the rotor 40 to the rotating shaft 50. In contrast, in this embodiment, the transmission plate 90 and the knock pins 91 contribute to torque transmission, reducing the torque load on the bolt 70. The rotational torque of the rotor 40 is distributed to the bolt 70 and the knock pins 91, and is transmitted mainly by the knock pins 91. The bolt 70 mainly functions to position the rotor 40 in the axial direction.

[0046] Particularly in this embodiment, the fit of the knock pin 91 is set to be strict with respect to the fit of the screw hole 52a of the bolt 70. This reduces the torque transmission to the bolt 70, which requires a guarantee of electrical insulation performance.

[0047] The bolt 70 and the knock pin 91 correspond to a torque transmission member that transmits torque from the rotor 40 to the rotating shaft 50. The bolt 70, which is a torque transmission member, is electrically insulated from the rotor 40 by the adhesive 81, the insulating film 94, and the washer 82, which are insulating layers.

[0048] A recess 42c into which the transmission plate 90 is fitted is formed in the rotor body 42. The recess 42c is recessed in the axial direction and does not penetrate the rotor body 42. One of the plate surfaces of the transmission plate 90 is entirely exposed from the recess 42c.

[0049] As described above, the rotating machine 10 according to this embodiment includes a torque transmission member that is electrically insulated from the rotor 40 by an insulating layer. This allows the transmission member to transmit the rotational torque of the rotor 40 to the rotating shaft 50, thereby reducing the torque load on the bolts 70. Even if the rotor 40 or the rotating shaft 50 is made of a non-metallic material such as resin, the above-mentioned torque distribution effect can suppress damage to the non-metallic parts and improve the reliability of electrical insulation.

[0050] Furthermore, in this embodiment, a recess 42c recessed in the axial direction is formed in the rotor body 42, and the transmission plate 90 is fitted into the recess 42c. Therefore, the weight of the rotor body 42 can be reduced by the amount of the recess 42c, and the size in the axial direction can be reduced.

[0051] Sixth embodiment The rotating machine 10 of this embodiment shown in Figures 12 and 13 includes an adhesive layer 85 between the insulating film transmission plate 90 and the rotor body 42. The adhesive layer 85 is formed by applying an adhesive to the surface of the portion of the transmission plate 90 that faces the rotor body 42. The adhesive layer 85 has a shape that spreads perpendicularly to the axial direction, and bonds the transmission plate 90 and the rotor body 42 in a planar manner.

[0052] According to this, the rotational torque of the rotor 40 is transmitted to the rotating shaft 50 not only by the knock pin 91 but also by the adhesive layer 85. Therefore, the torque load on the bolt 70 can be further reduced.

[0053] In the above-described fifth embodiment, the rotational torque is transmitted from the rotor 40 to the transmission plate 90 by using the bolts 70. In contrast, in this embodiment, the rotational torque is transmitted from the rotor 40 to the transmission plate 90 by the adhesive layer 85 in addition to the bolts 70. This makes it possible to further reduce the torque load on the bolts 70.

[0054] Seventh embodiment 14, the bolt 70 according to the fifth embodiment is replaced with a nut 70N. The rotating machine 10 includes the nut 70N and a washer 86. The nut 70N is fastened to a threaded portion 51a formed on the shaft main body 51.

[0055] The washer 86 is disposed between the rotor body 42 and the fastening portion 52, and is also disposed between the rotor body 42 and the nut 70N. When the nut 70N is fastened to the shaft body 51, the fastening force clamps and holds the rotor body 42 between the nut 70N and the fastening portion 52. This connects the rotor 40 and the rotating shaft 50, allowing them to rotate together.

[0056] While the nut 70N is made of metal, the washer 86 is made of an electrically insulating material. Specific examples of the material of the washer 86 include resins such as fluororesin and MC Nylon (registered trademark). The washer 86 is disposed at the connection portion between the rotor 40 and the rotating shaft 50, and functions as an insulating layer that electrically insulates the rotor 40 and the rotating shaft 50 from each other.

[0057] As described above, in this embodiment in which the bolt 70 is replaced with the nut 70N, the shaft voltage can be reduced without causing a temperature rise, similarly to the first embodiment.

[0058] (Other embodiments) In the first embodiment, the washer 82 may be replaced with adhesive 81. In this case, it is preferable to embed a mesh sheet 83 shown in FIG. 5 in the replaced portion of adhesive 81 to ensure the thickness of adhesive 81.

[0059] In the first embodiment, the adhesive 81 may be eliminated, and an electrically insulating washer may be provided between the head 71 of the bolt 70 and the rotor body 42. In this case, however, it is necessary to ensure a sufficient gap between the neck portion 72 of the bolt 70 and the through hole 42b.

[0060] The rotor 40, the rotary shaft 50, the transmission plate 90, the knock pin 91, and the bolt 70 are not limited to being made of metal, but may be made of resin. An example of a resin material is a resin material reinforced with carbon fiber (e.g., CFRP).

[0061] In the above-described fifth embodiment, the torque transmission member has the same potential as the rotating shaft 50, and is electrically insulated from the rotor 40 by the insulating layer. Alternatively, the torque transmission member may have the same potential as the rotor 40, and be electrically insulated from the rotating shaft 50 by the insulating layer. More specifically, in the above-described fifth embodiment, the knock pin 91 fits into the rotating shaft 50, and the insulating layer provides electrical insulation between the rotor 40 and the transmission plate 90. Alternatively, the knock pin 91 may fit into the rotor 40, and the insulating layer may provide electrical insulation between the rotating shaft 50 and the transmission plate 90.

[0062] In the sixth embodiment, the bolt 70 and the adhesive layer 85 are used to transmit the rotational torque from the rotor 40 to the transmission plate 90. Alternatively, the bolt 70 may be eliminated and the adhesive layer 85 may transmit the rotational torque from the rotor 40 to the transmission plate 90. In the fifth and sixth embodiments, the outer shape of the recess 42c when viewed in the axial direction is circular, but the recess 42c may be partially cut out and chamfered. In this case, the outer peripheral surface of the transmission plate 90 engages with the inner peripheral surface of the recess 42c at the chamfered portion. As a result, the rotational torque is transmitted from the rotor 40 to the transmission plate 90 by the chamfered portion of the recess 42c as well, and the torque load on the bolt 70 can be further reduced.

[0063] The nut 70N according to the seventh embodiment is made of metal, but may be made of a material having electrical insulation. In that case, the washer 95 may be eliminated, and the nut 70N may function as an insulating layer. Specific examples of the material of the insulating nut include resins such as fluororesin and MC nylon (registered trademark).

[0064] The rotating machine 10 according to each of the above embodiments is a double axial gap motor in which two rotors 40 are provided for one stator 30. In contrast, the rotating machine 10 may have a structure in which one rotor 40 is provided for one stator 30, or a structure in which one rotor 40 is provided for two stators 30. In addition, while the rotor 40 described above generates a field magnet with the magnet 41, the rotor 40 may be configured to include a field winding instead of the magnet 41.

[0065] The rotating machine 10 is not limited to being used for propeller power in an aircraft, but may also be used as a running power mounted on a vehicle, or as a stationary motor, generator, or the like.

[0066] Although the present disclosure has been described based on the embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, although various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more than one, or less than one element are also within the scope and concept of the present disclosure.

[0067] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple dependent claims. Some of the claims may be described in a multiple dependent form, where the subsequent claim alternatively refers to the preceding claim. Furthermore, some of the claims may be described in a multiple dependent form, where the subsequent claim alternatively refers to the preceding claim. The claims described in these multiple dependent forms define multiple technical ideas.

[0068] (Technical thought 1) A stator (30) that generates a rotating magnetic field; a rotor (40) arranged to provide an axial gap with respect to the stator; A rotating shaft (50) connected to the rotor; a rotating machine comprising: an insulating layer (81, 82, 83, 84, 85, 86, 94, 70i) disposed at a connection portion between the rotor and the rotating shaft, and providing electrical insulation between the rotor and the rotating shaft.

[0069] (Technical thought 2) a torque transmission member (90, 91) for transmitting torque from the rotor to the rotary shaft is provided between the rotor and the rotary shaft; The rotating machine described in Technical Idea 1, wherein the torque transmission member is electrically insulated from the rotor or the rotating shaft by the insulating layer.

[0070] (Technical Thought 3) the torque transmission member is electrically insulated from the rotor together with the rotating shaft by the insulating layer, The torque transmission member includes a transmission plate (90) having a first insertion hole (90b) formed in one plate surface, and a knock pin (91) having one end inserted into the first insertion hole, The other end of the knock pin is inserted into a second insertion hole (52b) formed in the rotating shaft, the other plate surface of the transmission plate is connected to the rotor with the insulating layer interposed therebetween; The rotating machine according to Technical Idea 2, wherein the rotational torque of the rotor is transmitted to the rotating shaft via the transmission plate and the knock pin.

[0071] (Technical Thought 4) Bolts (70, 70i) are provided to connect the rotor and the rotating shaft, The rotating machine according to Technical Idea 3, wherein the transmission plate is clamped between the rotor and the rotating shaft by the fastening force of the bolts.

[0072] (Technical Thought 5) The rotating machine according to Technical Concept 3 or 4, wherein the rotor is formed with a recess (42c) into which the other plate surface is fitted.

[0073] (Technical Thought 6) The rotating shaft has a fastening portion (52) extending in a radial direction of rotation, The rotor has a through hole (42b) penetrating in the direction of the rotation axis, The rotating machine according to any one of Technical Ideas 1 to 5, further comprising a bolt (70, 70i) that is inserted into the through hole and fastened to the fastening portion to connect the rotor and the rotating shaft.

[0074] (Technical Thought 7) An adhesive (81) is provided between the through hole and the bolt, The rotating machine described in Technical Idea 6, wherein the adhesive has electrical insulating properties so as to function as the insulating layer.

[0075] (Technical Thought 8) A spacer (83, 84) is provided between the through hole and the bolt to maintain a gap between an inner peripheral surface of the through hole and an outer peripheral surface of the bolt, The rotating machine described in Technical Idea 7, wherein the spacer has electrical insulation properties so as to function as the insulating layer.

[0076] (Technical Thought 9) The rotating machine described in Technical Idea 6, wherein the bolt has electrical insulation properties so as to function as the insulating layer.

[0077] (Technical Thought 10) The rotor has a shaft hole (42a) into which the rotating shaft is inserted, A rotating machine described in any one of Technical Ideas 1 to 9, wherein an air gap (42g) is formed between an inner circumferential surface of the shaft hole and an outer circumferential surface of the rotating shaft facing the inner circumferential surface. [Explanation of symbols]

[0078] 30 stator, 40 rotor, 42a shaft hole, 42b through hole, 42c recess, 42g air gap, 50 rotating shaft, 52 fastening portion, 52b second insertion hole, 70 bolt, 70i insulating layer, 70i bolt, 81 insulating layer, 81 adhesive, 82, 83 insulating layer, 83 spacer, 84 insulating layer, 84 spacer, 85, 86 insulating layer, 90 torque transmission member, 90 transmission plate, 90b first insertion hole, 91 torque transmission member, 91 knock pin, 94 insulating layer.

Claims

1. A stator (30) that generates a rotating magnetic field; A rotor (40) arranged to provide an axial gap with respect to the stator; A rotating shaft (50) connected to the rotor; an insulating layer (81, 82, 83, 84, 85, 86, 94, 70i) disposed at a connection portion between the rotor and the rotating shaft, and providing electrical insulation between the rotor and the rotating shaft.

2. a torque transmission member (90, 91) for transmitting torque from the rotor to the rotary shaft is provided between the rotor and the rotary shaft; The rotating machine according to claim 1 , wherein the torque transmission member is electrically insulated from the rotor or the rotating shaft by the insulating layer.

3. the torque transmission member is electrically insulated from the rotor together with the rotating shaft by the insulating layer, The torque transmission member includes a transmission plate (90) having a first insertion hole (90b) formed in one plate surface, and a knock pin (91) having one end inserted into the first insertion hole, The other end of the knock pin is inserted into a second insertion hole (52b) formed in the rotating shaft, the other plate surface of the transmission plate is connected to the rotor with the insulating layer interposed therebetween; The rotating machine according to claim 2 , wherein the rotational torque of the rotor is transmitted to the rotating shaft via the transmission plate and the knock pin.

4. A bolt (70, 70i) is provided for connecting the rotor and the rotating shaft, The rotating machine according to claim 3 , wherein the transmission plate is clamped between the rotor and the rotating shaft by fastening forces of the bolts.

5. The rotating machine according to claim 3 or 4, wherein the rotor is formed with a recess (42c) into which the other plate surface is fitted.

6. The rotating shaft has a fastening portion (52) extending in a radial direction of rotation, The rotor has a through hole (42b) penetrating in the direction of the rotation axis, The rotating machine according to any one of claims 1 to 4, further comprising a bolt (70, 70i) that is inserted into the through hole and fastened to the fastening portion to connect the rotor and the rotating shaft.

7. An adhesive (81) is provided between the through hole and the bolt, The rotating machine according to claim 6 , wherein the adhesive has an electrical insulating property so as to function as the insulating layer.

8. A spacer (83, 84) is provided between the through hole and the bolt to maintain a gap between an inner peripheral surface of the through hole and an outer peripheral surface of the bolt, The rotating machine according to claim 7 , wherein the spacer has an electrical insulating property so as to function as the insulating layer.

9. The rotating machine according to claim 6 , wherein the bolt has an electrical insulating property so as to function as the insulating layer.

10. The rotor has a shaft hole (42a) into which the rotating shaft is inserted, The rotating machine according to any one of claims 1 to 4, wherein an air gap (42g) is formed between an inner peripheral surface of the shaft hole and an outer peripheral surface of the rotating shaft facing the inner peripheral surface.

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