Rotary machine

Abstract

To provide a rotating machine which reduces a shaft voltage in a rotating shaft and achieves a long life.SOLUTION: The rotating machine 1 includes a cylindrical fixed element 12 fixed in a housing 14, and a cylindrical rotating element 11 fixed to a rotation axis S1 disposed coaxially with the fixed element 12 inside the fixed element 12. The rotator 11 is provided with an air gap 21 and a magnetic body 20 which forms a rotating magnetic field as the rotator 11 rotates, and the 21a of the opening of the air gap 21 which opens at the end of the rotator 11 in the axial direction X is covered with a dielectric region 25 which promotes electrostatic coupling between the rotator 11 and the stationary part 12.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a rotating machine. [Background technology]

[0002] It has been known that in a conventional device including a motor as a power source and an inverter that converts electric power, a shaft voltage caused by the inverter propagates through the power transmission path of the motor. The cause of this shaft voltage propagation is electrostatic coupling between the rotor and windings that make up the motor. This causes a shaft voltage to be generated on the rotating shaft of the motor via the electrostatic coupling. As a configuration for reducing this shaft voltage, Patent Document 1 listed below discloses a rotating machine configuration in which the rotating shaft is grounded via the housing using brushes and oil seals. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-244180 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration disclosed in Patent Document 1, the brushes and oil seals slide on the rotating shaft, which causes deterioration such as wear of the components and accelerates deterioration of the rotating machine. Therefore, there is room for improvement in order to extend the life of the rotating machine.

[0005] The present invention has been made in view of the above-mentioned problems, and aims to provide a rotating machine that reduces the shaft voltage on the rotating shaft and has a longer life. [Means for solving the problem]

[0006] A reference embodiment of the present invention includes a stator (12) fixed in a housing (14); a rotor (11) fixed to a rotating shaft (S1) arranged coaxially with the stator; a winding (13) provided on the stator to generate a magnetic flux in the stator as the rotor rotates; Equipped with The rotating machine (1) has conductors (16, 160, 165, 166, 167) that inhibit electrostatic coupling between the rotor ends (111, 112), which are the axial ends of the rotor shaft in the rotor, and the winding ends (131, 132), which are the axial ends of the windings in the rotor shaft, at positions spaced apart from the rotor and the rotating shaft.

[0007] Another aspect of the present invention is a rotor including a cylindrical stator (12) fixed in a housing (14); a cylindrical rotor (11) fixed to a rotating shaft (S1) arranged coaxially with the stator inside the stator; Equipped with The rotor is provided with an air gap (21) and a magnetic body (20) that generates a rotating magnetic field as the rotor rotates, The opening (21a) of the air gap at the axial end of the rotor is in a rotating machine (1) covered by a dielectric region (25) that promotes electrostatic coupling between the rotor and the stator. [Effects of the Invention]

[0008] The inventors of the present application have noticed that in a rotating machine, reducing the electrostatic coupling between the rotor end and the winding end, which are the respective ends of the rotor and the winding, reduces the shaft voltage of the rotating shaft. Therefore, in the rotating machine of the above-mentioned reference aspect, a conductor that blocks the electrostatic coupling between the rotor end and the winding end is provided between the rotor end and the winding end, at a position spaced apart from the rotor and the rotating shaft. This prevents the electrostatic coupling between the rotor end and the winding end, thereby reducing the shaft voltage of the rotating shaft. Furthermore, because the conductor is spaced apart from the rotor and the rotating shaft, the conductor does not slide against the rotor and the rotating shaft, preventing deterioration such as wear that occurs when brushes or oil seals are used, thereby extending the life of the rotating machine.

[0009] The inventors of the present invention have noticed that increasing the electrostatic coupling between the stator and rotor in a rotating machine reduces the shaft voltage of the rotating shaft. Therefore, in the rotating machine of the above-described embodiment, the opening of the gap at the axial end of the rotor is covered with a dielectric region that promotes electrostatic coupling between the rotor and stator. This dielectric region increases the electrostatic coupling between the rotor and stator, thereby reducing the shaft voltage of the rotating shaft. Furthermore, because the dielectric region does not require a sliding structure, it is possible to prevent deterioration such as wear that occurs when using brushes or oil seals, thereby extending the life of the rotating machine.

[0010] As described above, according to the above-described reference and one aspects, it is possible to provide a rotating machine in which the shaft voltage in the rotating shaft is reduced and the life span is extended.

[0011] In addition, the symbols in parentheses in the claims and the means for solving the problems indicate the correspondence with the specific means described in the embodiments described below, and do not limit the technical scope of the present invention. [Brief explanation of the drawings]

[0012] [Figure 1]FIG. 1 is a plan view showing an outline of a vehicle in a first reference embodiment. [Figure 2] 1 is a schematic diagram of a rotating machine according to a first embodiment; [Figure 3] FIG. 2 is a diagram showing a simple equivalent circuit of a rotating machine in the first reference embodiment. [Figure 4] FIG. 10 is a schematic diagram of a rotating machine according to a second embodiment. [Figure 5] FIG. 11 is a schematic diagram of a rotating machine according to a third embodiment. [Figure 6] FIG. 10 is a schematic diagram of a rotating machine according to a fourth embodiment. [Figure 7] FIG. 13 is a schematic diagram of a rotating machine according to a fifth embodiment. [Figure 8] FIG. 20 is a schematic diagram of a rotating machine according to a sixth embodiment. [Figure 9] FIG. 13 is a schematic diagram of a rotating machine according to a seventh embodiment. [Figure 10] FIG. 19 is a schematic diagram of a rotating machine according to an eighth embodiment. [Figure 11] 1A is a schematic diagram of a rotating machine according to a first embodiment; FIG. 1B is a cross-sectional view of a stator taken along line XIb-XIb in FIG. 1A; and FIG. 1C is a cross-sectional view of a stator taken along line XIc-XIc in FIG. [Figure 12] 10A is a schematic diagram of a rotating machine according to a second embodiment; FIG. 10B is a cross-sectional view of the stator taken along line XIIb-XIIb in FIG. 10A; and FIG. 10C is a cross-sectional view of the stator taken along line XIIc-XIIc in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of a power conversion device will be described with reference to the drawings. This embodiment is typically mounted on a vehicle such as an electric vehicle or a hybrid vehicle, and is suitably applied to an on-board power conversion device that performs power conversion between DC power and AC power. In this specification, unless otherwise specified, the axial direction of a rotating shaft is indicated by X, and the radial direction of the rotating shaft is indicated by Y.

[0014] (Reference form 1) The rotating machine 1 of this reference embodiment 1, which is the above-described reference mode, is mounted on a vehicle 100 shown in Fig. 1. As shown in Fig. 1, the vehicle 100 is an electric vehicle that includes the rotating machine 1, a vehicle body 2, left and right drive wheels 3, an inverter 4, a battery 5, and a reduction gear 7.

[0015] The rotating machine 1 is configured as a motor generator that combines the functions of a motor and a generator. The rotating machine 1 includes a rotating shaft S1 that is a motor shaft, a rotor 11 that rotates integrally with the rotating shaft S1, a coil 13 that serves as a winding, and a stator 12 that serves as a stator around which the coil 13 is wound. The rotating machine 1 is controlled by an inverter 4.

[0016] The inverter 4 is a semiconductor module having a plurality of switching elements (not shown) connected to electrodes of any of the three phases (U phase, V phase, W phase) of the rotating machine 1, and is used to perform power conversion. The inverter 4 is electrically connected to the coil 13 of the rotating machine 1, and is also electrically connected to the battery 5 via a harness 6.

[0017] The reducer 7 is for transmitting the driving force of the rotating machine 1 to the drive wheels 3. The reducer 7 is provided with three rotating shafts S2, S3, and S4. Of the three rotating shafts S2, S3, and S4, the rotating shaft S2 is provided at the most upstream position in a power transmission path formed with the rotating machine 1 side upstream and the drive wheels 3 side downstream. The rotating shaft S3 is provided between the rotating shafts S2 and S4 in the power transmission path A. The rotating shaft S4 is a drive shaft provided to connect the differential gear G5 and the two drive wheels 3. The reducer 7 is also referred to as a transmission.

[0018] The rotating machine 1 of the first embodiment will be described in detail below. 2, the rotating machine 1 includes a housing 14, and the housing 14 houses the rotor 11, the stator 12, and the coil 13. In the first embodiment, the housing 14 includes a housing main body 141 that is substantially cylindrical with a bottom and has an opening on one side in the axial direction X, and a housing lid 142 that covers the opening side of the housing main body 141. Note that the configuration of the housing 14 is not limited to this, and the housing main body may be cylindrical with both ends open, and may include two housing lids that respectively cover both openings.

[0019] As shown in Fig. 2, rotor 11 as a rotor has a cylindrical shape. Rotor 11 is provided with a plurality of magnets as magnetic bodies (not shown). Rotating shaft S1 is press-fitted into the inside of rotor 11, and the two are integrated. Rotating shaft S1 extends in axial direction X and is supported by two bearings 15 so as to be rotatable.

[0020] In this reference embodiment 1, the stator 12 serving as a stator has a cylindrical shape and is fixed to a housing body 141, with the rotor 11 and the rotation axis S1 located inside the stator 12. The stator 12 is provided with a coil 13. Winding ends 131, 132, which are ends of the coil 13 in the axial direction X, protrude outward in the axial direction X from the stator 12 and are located outward of a rotor end 111, which is an end of the rotor 11 in the axial direction. As a result, a space P is formed between inner surfaces 131 a, 132 a in the radial direction Y of the winding ends 131, 132 and the axial end faces 111 a, 112 a of the rotor ends 111, 112. Meanwhile, a winding center portion 133 in the axial direction X of the coil 13 is located within the stator 12.

[0021] As shown in FIG. 2 , a portion of the coil end shield 16, which serves as a conductor that inhibits the formation of electrostatic coupling between the rotor ends 111, 112 and the winding ends 131, 132, is located in the space P. The coil end shield 16 is made of a conductive material and includes a cylindrical portion 161 and a flange portion 162. The flange portion 162 is formed to extend outward in the radial direction Y from one end of the cylindrical portion 161. The flange portion 162 is fixed to the housing 14 via screws 17 and functions as a fixing portion that fixes the coil end shield 16 to the housing 14. The cylindrical portion 161 functions as an extension portion that extends from the flange portion 162 toward the axial end faces 111 a, 112 a of the rotor ends 111, 112. The tip of the cylindrical portion 161 in the extension direction that faces the axial end faces 111 a, 112 a, i.e., the other end opposite the flange portion 162, is located in the space P described above.

[0022] In this reference form 1, the cylindrical portion 161 serving as an extension portion extends from the inner periphery of the flange portion 162. The coil end shield 16 is separated from the rotor 11 and the rotation axis S1 and is not in physical contact with them. In this reference form 1, the cylindrical portion 161 of the coil end shield 16 extends in the axial direction X along the radially inner surfaces 131 a, 132 a of the winding ends 131, 132.

[0023] In this reference form 1, the extension portion of the coil end shield 16 is the cylindrical portion 161 and has a shape that is continuous in the circumferential direction, but the shape of the extension portion is not limited to this, and it may have a portion that is discontinuous in the circumferential direction, i.e., a gap. In this reference form 1, the tip end portion of the cylindrical portion 161 on the side opposite the flange portion 162 is separated from the stator 12 and does not contact each other, but it is preferable that this tip end portion be as close as possible to the stator 12. In this reference form 1, the coil end shields 16 are provided at both ends of the rotor 11 in the axial direction X, but instead, they may be provided at either one of them.

[0024] The equivalent circuit of the power transmission path A in FIG. 1 up to the shaft S2 can be simply represented by the equivalent circuit shown in FIG. 3. The shaft voltage, which is the source of noise propagating to the rotating shaft S1, is proportional to the parasitic capacitance between the coil 13 and the rotor 11 in path I shown in FIG. 3. That is, the larger the parasitic capacitance between the coil 13 and the rotor 11, the greater the noise propagating to the rotating shaft S1. On the other hand, the parasitic capacitance between the stator 12 and the rotor 11 and the parasitic capacitance between the inner and outer rings of the bearing 15 in path II shown in FIG. 3 strengthens the electrostatic coupling between the stator 12 and the rotor 11. This reduces the shaft voltage. Furthermore, the higher the parasitic capacitance between the stator 12 and the rotor 11 and the parasitic capacitance between the inner and outer rings of the bearing 15, the smaller the impedance between the rotor 11 and the stator 12. This makes it easier for high-frequency noise components to be conducted compared to a conventional configuration with brushes, thereby reducing noise.

[0025] The inventors compared the parasitic capacitance between coil 13 and rotor 11 between winding end portions 131 and 132 and winding center portion 133 of coil 13 shown in FIG. 2 and found that the parasitic capacitance generated at winding end portions 131 and 132 is sufficiently larger than the parasitic capacitance generated at winding center portion 133. Based on this, they learned that reducing the parasitic capacitance between winding end portions 131 and 132 and rotor 11 is effective in reducing the shaft voltage. The parasitic capacitance can be reduced by inhibiting the formation of electrostatic coupling between winding end portions 131 and 132 and rotor 11.

[0026] Next, the effects of the first embodiment will be described. In the rotating machine 1 of Reference Form 1, a coil end shield 16 is provided as a conductor that inhibits electrostatic coupling between the rotor ends 111, 112 and the winding ends 131, 132, at a position spaced apart from the rotor 11 and the rotating shaft S1. This inhibits electrostatic coupling between the rotor ends 111, 112 and the winding ends 131, 132, thereby reducing the shaft voltage on the rotating shaft S1. Furthermore, because the coil end shield 16 is spaced apart from the rotor 11 and the rotating shaft S1, the coil end shield 16 does not slide against the rotor 11 and the rotating shaft S1, preventing deterioration due to wear and achieving a longer life.

[0027] Furthermore, in this reference form 1, the winding ends 131, 132 are located outward in the axial direction X from the rotor ends 111, 112, and at least a portion of the coil end shield 16 as a conductor is located within a space P surrounded by radially inner surfaces 131a, 132a of the winding ends 131, 132 and the axial end surfaces 111a, 112a of the rotor ends 111, 112. This allows the portion of the coil end shield 16 as a conductor to be reliably positioned at a position that inhibits the formation of electrostatic coupling between the rotor ends 111, 112 and the winding ends 131, 132, thereby further reducing the axial voltage on the rotating shaft S1.

[0028] Furthermore, in this reference form 1, the coil end shield 16 as a conductor comprises a flange portion 162 which is a fixed portion fixed to the housing 14, and a cylindrical portion 161 which is an extension portion extending from the flange portion 162 toward the axial end faces 111a, 112a of the rotor 11 as a rotor. As a result, the coil end shield 16 is connected to the housing 14 at the flange portion 162 and is grounded, thereby inhibiting the formation of electrostatic coupling between the rotor ends 111, 112 and the winding ends 131, 132 at the cylindrical portion 161 which is an extension portion, thereby further achieving the effect of reducing the axial voltage on the rotating shaft S1.

[0029] As described above, according to the first embodiment, it is possible to provide a rotating machine 1 that reduces the shaft voltage on the rotating shaft S1 and has a longer life.

[0030] (Reference form 2) In the above-described first embodiment, the coil end shield 16 formed as a separate member from the housing 14 is provided as a conductor. However, in the present second embodiment, as shown in FIG. 4, a cylindrical coil end shield 160 is formed as a conductor and protrudes from the inner surface of the housing 14. The coil end shield 160 is made of the same material as the housing main body 141 and is formed integrally with the housing 14. The shape of the coil end shield 160 can be the same as the cylindrical portion 161 in the first embodiment. Furthermore, the same reference numerals as in the first embodiment are used for components equivalent to those in the first embodiment, and their description will be omitted.

[0031] According to this reference form 2, as described above, the coil end shield 160 as a conductor is made of the same material as the housing 14 and is formed to protrude from the inner surface of the housing 14 toward the axial end faces 111a, 112a of the rotor 11, and is configured integrally with the housing 14, thereby reducing the number of parts and improving assembly workability.

[0032] (Reference form 3) 5, in this reference form 3, a bearing 15 that supports the rotation shaft S1 is provided in the housing 14, and a part of the coil end shield 16, which is an electric conductor, forms part of a fixing part that fixes the bearing 15 to the housing 14. Other components that are not specifically mentioned are the same as those in reference form 1, and the same reference numerals as in reference form 1 are used, and their description will be omitted.

[0033] 5, in the present embodiment, a recess 143 is formed in the housing 14, which is open to the inside of the housing 14 and conforms to the outer shape of the bearing 15. The bearing 15 is fitted into the recess 143.

[0034] In the coil end shield 16 of the first embodiment described above, the cylindrical portion 161 serving as an extension portion extends from the inner circumferential portion of the flange portion 162, but in the third embodiment, the cylindrical portion 161 serving as an extension portion extends from the outer circumferential end of the flange portion 162. The inner circumferential portion of the flange portion 162 forms a fixing portion 163 that covers the bearing 15 fitted into the recess 143 to prevent the bearing 15 from falling out of the recess 143 and fixes the bearing 15 to the housing 14.

[0035] In the present reference form 3, by having the above-described configuration, the coil end shield 16 has a fixing portion 163 that fixes the bearing 15 to the housing 14. This eliminates the need to prepare a separate fixing member that fixes the bearing 15 to the housing 14, thereby reducing the number of parts. Note that the present reference form 3 also achieves the same effects as the reference form 1.

[0036] (Reference form 4) In the above-described first embodiment, the cylindrical portion 161 of the coil end shield 16 extends in the axial direction X along the inner surfaces 131 a, 132 a of the winding ends 131, 132 toward the axial end faces 111 a, 112 a of the rotor ends 111, 112. However, in this fourth embodiment, as shown in FIG. 6 , the cylindrical portion 161 of the coil end shield 16 extends in the axial direction X along the rotation axis S1 toward the axial end faces 111 a, 112 a. The cylindrical portion 161 has a smaller diameter than that of the first embodiment shown in FIG. 2 , and the rotor-side end of the cylindrical portion 161 further includes a rotor-facing portion 164 that extends outward in the radial direction Y along the axial end faces 111 a, 112 a. At least the rotor-facing portion 164 is located in the space P. Other configurations not specifically mentioned are the same as those in the first embodiment, and the same reference numerals as those in the first embodiment are used, and their description will be omitted.

[0037] In this fourth embodiment, as described above, the coil end shield 16 serving as a conductor has a rotor-facing portion 164 that extends parallel to and faces the rotor ends 111, 112 of the rotor 11. This prevents electrostatic coupling between the rotor ends 111, 112 and the winding ends 131, 132 at the rotor-facing portion 164, thereby reducing the axial voltage at the rotating shaft S1 and further enhancing the axial voltage reduction effect by reducing the impedance between the rotor 11 and the housing 14. Furthermore, since the diameter of the cylindrical portion 161 of the coil end shield 16 can be made relatively small, the amount of material required can be reduced, resulting in a reduction in weight. Note that this fourth embodiment also achieves the same effects as those of the first embodiment.

[0038] (Reference form 5) In the case of the above-described Reference Embodiment 4, the diameter of the cylindrical portion 161 of the coil end shield 16 was reduced. However, instead, in the present Reference Embodiment 5 shown in FIG. 7, the diameter of the cylindrical portion 161 of the coil end shield 16 is the same as in the case of the first embodiment shown in FIG. 2, and a rotor-facing portion 164 is provided at the end of the cylindrical portion 161 on the rotor 11 side. In the present Reference Embodiment 5, the rotor-facing portion 164 is formed by extending inward in the radial direction Y from the end of the cylindrical portion 161 on the rotor 11 side. As a result, the cylindrical portion 161 and the rotor-facing portion 164 are located in the space P. Other configurations that are not particularly mentioned are the same as those in the Reference Embodiment 1, and the same reference numerals as in the Reference Embodiment 1 are used, and description thereof will be omitted.

[0039] The fifth embodiment also provides the same effects as the fourth embodiment, except for the effects obtained by reducing the diameter of the cylindrical portion 161 of the coil end shield 16 in the fourth embodiment.

[0040] (Reference form 6) In this reference embodiment 6, as shown in Fig. 8, bent portions 121a, 122a are formed by bending parts of inner peripheries of steel plates 121, 122 located at axial ends of a laminated steel plate forming a stator 12 as a stator outward in the axial direction X. The steel plates 121, 122 having bent portions 121a, 122a are located at axial ends of the laminated steel plate forming the stator 12, and therefore contribute little to the flow of magnetic flux generated in the stator 12. Therefore, the bent portions 121a, 122a are located in the space P, and function as coil end shields 165 that inhibit the formation of electrostatic coupling between the rotor ends 111, 112 and the winding ends 131, 132. In this reference embodiment 6, a plurality of bent portions 121a, 122a are provided, and are arranged at equal intervals in the circumferential direction. The length of the bent portions 121a, 122a in the axial direction X is not limited, and in this reference form 6, they are located axially inside the tip positions of the winding ends 131, 132, which are the ends of the coil 13 in the axial direction X, but they may also be located axially outside the tip positions.

[0041] According to the sixth embodiment, the electrostatic coupling between the rotor ends 111, 112 and the winding ends 131, 132 is strongest at the bases of the winding ends 131, 132 where they protrude from the stator 12. Therefore, by forming the coil end shield 165 using the bent portions 121a, 122a, the coil end shield 165 can be positioned close to the area where the electrostatic coupling is strongest, further enhancing the effect of reducing the axial voltage. Furthermore, because the coil end shield 165 is formed integrally with the stator 12, the number of parts can be reduced and the weight can be reduced.

[0042] (Reference form 7) In the above-described sixth embodiment, the coil end shields 165 are formed by the bent portions 121a, 122a of the steel plates 121, 122 located at the axial ends. However, in the seventh embodiment, as shown in Fig. 9, stator extensions 121b, 122b are formed by extending radially inward part of the inner peripheries of the steel plates 121, 122 located at the axial ends of the laminated steel plates that form the stator 12. The stator extensions 121b, 122b face the rotor ends 111, 112 while being spaced apart. As a result, the stator extensions 121b, 122b are located in the space P and function as coil end shields 166 that inhibit the formation of electrostatic coupling between the rotor ends 111, 112 and the winding ends 131, 132.

[0043] The seventh embodiment also has the same effects as the sixth embodiment.

[0044] (Reference form 8) 10 , in the present embodiment, coil end shields 167 as conductors are formed as separate members from stator 12 as a fixed element, and are fixed to the axial end of stator 12. Coil end shields 167 are electrically connected to stator 12.

[0045] Coil end shield 167 is made of a conductive material, extends parallel to an axial end of stator 12, and has a flange portion 167a fixed to the axial end, and a cylindrical portion 167b extending outward in axial direction X from an inner periphery of flange portion 167a. The length of cylindrical portion 167b in axial direction X is not limited, and in the eighth embodiment, cylindrical portion 167b has a length that extends to a position outward in axial direction X from winding ends 131, 132. However, cylindrical portion 167b may have a length that extends to a position inward in axial direction X from winding ends 131, 132.

[0046] According to the present embodiment, the coil end shield 167 fixed to the stator 12 is a separate member from the stator 12, and therefore, the shaft voltage can be reduced more effectively by separating it from the output of the rotating machine 1. Note that the present embodiment also achieves the same effects as the first embodiment.

[0047] (Embodiment 1) As shown in FIG. 11( a), the rotating machine 1 in the first embodiment, which is another aspect of the above, includes a stator 12 as a cylindrical stator fixed within a housing 14, and a rotor 11 as a cylindrical rotor fixed to a rotation axis S1 arranged coaxially with the stator 12 inside the stator 12. Furthermore, as shown in FIG. 11( b), the rotor 11 is provided with an air gap 21 and a magnetic body 20 that generates a rotating magnetic field as the rotor 11 rotates. As shown in FIG. 11( c), an opening 21a of the air gap 21 that opens at an end of the stator 12 in the axial direction X is covered by a dielectric region 25 that promotes electrostatic coupling between the stator 12 and the rotor 11. Meanwhile, the end of the magnetic body 20 in the axial direction X is covered by a metal end plate 18 provided at rotor ends 111 and 112 of the rotor 11. The end plate 18 prevents the magnetic body 20 from protruding. The gap 21 is provided for at least one of the purposes of functioning as a flux barrier that limits the magnetic flux path, and for cooling and weight reduction.

[0048] The dielectric region 25 is a region with a high dielectric constant, and in this embodiment 1, as shown in Fig. 11(c), the end plates 18 are formed in a cross shape in a plan view, so that the space where the metal end plates 18 are not present constitutes the dielectric region 25. The dielectric constant of the dielectric region 25 where the metal end plates 18 are not present is higher than that of the region where the metal end plates 18 are present. Note that the same reference symbols are used for components equivalent to those in Reference Embodiment 1, and their description will be omitted.

[0049] According to the present embodiment 9, the dielectric region 25 promotes and strengthens the electrostatic coupling between the rotor 11 and the stator 12 via the air gap 21. As the electrostatic coupling between the stator and the rotor increases, the axial voltage of the rotating shaft S1 also decreases accordingly. As a result, the axial voltage can be reduced. Furthermore, since the dielectric region 25 does not require a sliding structure, deterioration due to wear can be prevented, and a longer life can be achieved.

[0050] (Embodiment 2) In the first embodiment described above, the dielectric region 25 is formed by a space where the metal end plate 18 is not present. However, in the second embodiment, instead, an end plate 181 shown in FIG. 12(a) is made of resin and has a higher dielectric constant than the end plate 18 of the first embodiment. The magnetic body 20 shown in FIGS. 12(a) and 12(b) is exposed at the rotor ends 111 and 112, forming the magnetic body exposed portion 20a as shown in FIG. 12(a). As shown in FIG. 12(b), the magnetic body exposed portion 20a of the magnetic body 20 and the opening 21a of the gap 21 are covered with the resin member 181. Thus, the dielectric region 25 is formed by the resin member 181. Note that the same components as those in the first embodiment are designated by the same reference numerals, and their description will be omitted.

[0051] According to the second embodiment, the dielectric region 25 is formed by the resin member 181, which is a dielectric material, and the electrostatic coupling between the rotor 11 and the stator 12 is promoted and strengthened. This provides the same effects as those of the ninth embodiment.

[0052] (Other variations) In the first and second embodiments, a rotating machine having a configuration in which coil 13 is arranged on the outside of rotor 11 made of magnets is exemplified, but the present invention is not limited to this. A rotating machine having a configuration in which rotor 11 is made of inner windings and coil 13 is made of outer windings may also be used. A rotating machine having a configuration in which coil 13 is arranged on the inside of rotor 11 made of magnets may also be used. In this way, the present invention can be applied to rotating machines having various types of windings.

[0053] The present invention is not limited to the exemplary embodiments described above, and various applications and modifications are possible without departing from the scope of the present invention. [Explanation of symbols]

[0054] 1...rotating machine, 11...rotor, 111, 112...rotor end, 111a, 112a...axial end face, 12...stator, 13...winding (coil), 131, 132...winding end, 131a, 132a...radially inner surface, 133...winding center, 14...casing, 15...bearing, 16, 160, 165, 166, 167...conductor (coil end shield), 18...end plate, 181...resin member, 20...magnetic material, 21...air gap, 21a...opening, 25...dielectric region, 100...vehicle

Claims

1. a cylindrical stator (12) fixed in a housing (14); a cylindrical rotor (11) fixed to a rotating shaft (S1) arranged coaxially with the stator inside the stator; Equipped with The rotor is provided with an air gap (21) and a magnetic body (20) that forms a rotating magnetic field as the rotor rotates, The rotor has an opening (21a) of the gap at an axial end thereof, the opening (21a) being covered with a dielectric region (25) that promotes electrostatic coupling between the rotor and the stator.

2. The end of the stator has a magnetic material exposed portion (20a) where a part of the magnetic material is exposed, The exposed magnetic material portion and the opening of the gap are covered with a resin member (181), The rotating machine according to claim 1 , wherein the dielectric region is formed by the resin member.

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