Conductors, conductive devices and electric motors

Abstract

The present invention provides a conductor, a conductive device, and an electric motor equipped with the conductive device, which reduce wear due to rotation. [Solution] This conductor 60 and conductive device 80 achieves electrical conductivity between the stationary side and the rotating side by utilizing a rolling bearing, or so-called bearing, made of conductive metal. An inner conductive ring 66 is fixed to the inner ring 62 that constitutes the bearing, and an outer conductive ring 68 is fixed to the outer ring 64. At this time, an outer gap L1 is provided between the inner conductive ring 66 and the outer ring 64, and an inner gap L2 is provided between the outer conductive ring 68 and the inner ring 62, so that they do not come into contact with each other. A conductive lubricant G is impregnated into these gaps L1 and L2, and the outer ring 64 and the outer conductive ring 68 are electrically connected to the inner ring 62 and the inner conductive ring 66 via this conductive lubricant G without contact. As a result, no wear or frictional heat is generated in the conductive parts during rotation. In addition, because conductivity is maintained in a non-contact state, stable conductivity can be maintained even at high speed rotation.

Description

[Technical Field]

[0001] The present invention relates to a conductive member excellent in wear resistance and conductivity during rotation, a conductive device, and an electric motor including the conductive device. [Background Art]

[0002] In recent years, from the perspective of reducing carbon dioxide emissions, the popularization of hybrid vehicles such as HEVs (Hybrid Electric Vehicles) and PHEVs (Plug-in Hybrid Electric Vehicles) that use both an internal combustion engine and an electric motor, and electric vehicles such as BEVs (Battery Electric Vehicles) and FCVs (Fuel Cell Vehicles) has been promoted. Such hybrid vehicles and electric vehicles have a high-output electric motor (motor) that rotates wheels by electric power as a drive source. For this reason, further higher efficiency and higher output are required for these electric motors. Here, the inventors of the present invention have made the invention described in the following [Patent Document 1] that enables high output by rotating the stator of the electric motor and using the rotational force of this stator for the rotation of the rotor.

[0003] In addition, in connection with the invention described in [Patent Document 1], the inventors of the present application have made the invention described in the following [Patent Document 2] relating to a slip ring excellent in wear resistance that relieves the pressing force from the fixed electrode side by elastic deformation of the sliding insulating part and conducts electricity in a critical contact state where the pressing force is extremely small. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent No. 6729888 [Patent Document 2] Japanese Patent No. 6843365 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] The invention described in [Patent Document 2] made it possible to obtain a slip ring with superior wear resistance compared to conventional slip rings. However, even though it is in a critical contact state, the invention described in [Patent Document 2] still experiences wear due to continuous use because the electrodes are in contact and conductive. The present invention has been made in view of the above circumstances, and aims to provide a conductor, a conductive device, and an electric motor equipped with the conductive device that further reduce wear due to rotation. [Means for solving the problem]

[0006] The present invention (1) An inner ring 62 made of a conductive metal, and an outer ring 64 made of a conductive metal, The system comprises: a plurality of rolling elements 61 installed between the outer circumferential surface of the inner ring 62 and the inner circumferential surface of the outer ring 64 to rotate the outer ring 64 or the inner ring 62; an inner conductive ring 66 that is conductive, does not contact the outer ring 64, maintains a predetermined outer gap L1, and is electrically connected to the inner ring 62; an outer conductive ring 68 that is conductive, does not contact the inner ring 62, maintains a predetermined inner gap L2, and is electrically connected to the outer ring 64; and a conductive lubricant G impregnated into the inner gap L2 and the outer gap L1. The above problem is solved by providing a conductor 60 characterized in that the inner conductive ring 66 and the outer conductive ring 68 are electrically connected via the inner ring 62, the outer ring 64 and the conductive lubricant G. (2) The above problem is solved by providing the conductor 60 described in (1) above, characterized in that a conductive lubricant G is applied to the rolling element 61 and the conductive lubricant G is impregnated into the outer gap L1 and the inner gap L2 by the rotation of the rolling element 61. (3) The above problem is solved by providing the conductor 60 described in (1) above, which is characterized in that it has a bearing for a rotating shaft 10 that rotates separately from the inner ring 62 on the inner circumference side of the inner ring 62. (4) The above problem is solved by providing a conductive device 80 characterized in that a plurality of the conductive devices 60 described in (1) above are installed coaxially in the radial direction. (5) The conductive device 80 described in (4) above, comprising a first conductor 60A, a second conductor 60B, and a third conductor 60C arranged radially from the inner circumference, An inner ring holder 82 holds the inner conductive rings 66A, 66B, and 66C of the first conductor 60A, the second conductor 60B, and the third conductor 60C in an insulated state, The stator 40 is fixed to the inner ring holder 82, A first field coil 42A fixed to the stator 40 and receiving power via the inner conductive ring 66A of the first conductor 60A, a second field coil 42B fixed to the stator 40 and receiving power via the inner conductive ring 66B of the second conductor 60B, and a third field coil 42C fixed to the stator 40 and receiving power via the inner conductive ring 66C of the third conductor 60C, An outer ring holder 84 holds the outer conductive rings 68A, 68B, and 68C of the first conductor 60A, the second conductor 60B, and the third conductor 60C in an insulated state, A first power supply line 14A that supplies power to the outer conductive ring 68A of the first conductor 60A, a second power supply line 14B that supplies power to the outer conductive ring 68B of the second conductor 60B, and a third power supply line 14C that supplies power to the outer conductive ring 68C of the third conductor 60C, A rotating shaft 10 is provided, with at least one end inserted into a bearing located on the inner circumference side of the conductive device 80, and rotating independently of the conductive device 80. A rotor 30 fixed to the aforementioned rotating shaft 10, The above problems are solved by providing electric motors 100a and 100b, which are characterized by having a magnetic member (field magnet 32, rotor core 36) provided on the rotor 30 that rotates the rotor 30 by the magnetic field generated by the first field coil 42A, the second field coil 42B, and the third field coil 42C. [Effects of the Invention]

[0007] The conductor and conductive device according to the present invention utilize rolling bearings, or so-called bearings, to provide electrical conductivity between the stationary and rotating sides. An inner conductive ring is fixed to the inner ring of the bearing, and an outer conductive ring is fixed to the outer ring. An external gap L1 is provided between the inner conductive ring and the outer ring, and an internal gap L2 is provided between the outer conductive ring and the inner ring, ensuring non-contact between them. A conductive lubricant G is then impregnated into these gaps L1 and L2 to provide non-contact electrical conductivity between them. As a result, the conductor and conductive device according to the present invention do not generate wear or frictional heat at the conductive parts during rotation. Furthermore, because conductivity is maintained in a non-contact state, stable conductivity can be maintained even at high-speed rotation. In addition, in a configuration where the bearing is on the inner circumference side of the inner ring, the conductor or conductive device according to the present invention can also serve as the bearing on at least one side of the rotating shaft, thereby reducing material costs and enabling miniaturization and space saving. Furthermore, an electric motor using the conductive device according to the present invention has the above effects and can have high reliability, high durability, and a long lifespan even during long-term high-speed operation. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic exploded perspective view of the conductor according to the present invention. [Figure 2] This is a schematic cross-sectional view of the conductor according to the present invention. [Figure 3] This graph shows the rotational speed and current change of the conductor according to the present invention. [Figure 4] This is a schematic cross-sectional view of a conductive device according to the present invention. [Figure 5] This is a schematic cross-sectional view of an electric motor according to the first embodiment of the present invention. [Figure 6] This is a schematic cross-sectional view of a second embodiment of an electric motor according to the present invention. [Modes for carrying out the invention]

[0009] Embodiments of the conductor 60, the conductive device 80, and the electric motors 100a and 100b equipped with this conductive device according to the present invention will be described with reference to the drawings. Here, Figure 1 is a schematic exploded perspective view of the conductor 60 according to the present invention, and Figure 2 is a schematic cross-sectional view.

[0010] First, the conductor 60 according to the present invention comprises an inner ring 62 and an outer ring 64, which constitute a well-known rolling bearing, or so-called bearing, made of a conductive metal; a plurality of rolling elements 61 installed between the outer circumferential surface of the inner ring 62 and the inner circumferential surface of the outer ring 64 to rotate the inner ring 62 or the outer ring 64; and a cage (not shown) that holds these rolling elements 61 in a ring shape. In addition to these components, the conductor 60 according to the present invention also comprises an inner conductive ring 66 fixed to the inner ring 62 and an outer conductive ring 68 fixed to the outer ring 64, and a conductive lubricant G is impregnated between the outer ring 64 and the inner conductive ring 66 and between the inner ring 62 and the outer conductive ring 68.

[0011] Furthermore, the inner conductive ring 66 is composed of, for example, a cylindrical portion 67a and a flange portion 67b that protrudes outward from one end of the cylindrical portion 67a. The outer diameter of the cylindrical portion 67a is formed to be approximately the same as the inner diameter of the inner ring 62, and the inner conductive ring 66 is fixed to the inner ring 62 by fitting the cylindrical portion 67a into the inner ring 62. The inner ring 62 and the inner conductive ring 66 are then electrically connected and conduct electricity. The outer diameter of the flange portion 67b is formed to be approximately the same as the outer diameter of the outer ring 64. However, a predetermined outer gap L1 is provided between the flange portion 67b and the end face of the outer ring 64, so that the inner conductive ring 66 and the outer ring 64 are not in contact.

[0012] Further, the outer conductive ring 68 is composed of, for example, a cylindrical cylindrical portion 69a and an end face ring portion 69b projecting inward from one end of the cylindrical portion 69a. The inner diameter of the cylindrical portion 69a is formed to be substantially equal to the outer diameter of the outer ring 64, and the outer conductive ring 68 is fixed to the outer ring 64 by fitting the outer ring 64 into the cylindrical portion 69a. The outer ring 64 and the outer conductive ring 68 are electrically connected to conduct electricity. Further, the inner diameter of the end face ring portion 69b is formed to be substantially equal to the inner diameter of the inner ring 62. However, an inner gap L2 of a predetermined dimension is provided between the end face ring portion 69b and the end face of the inner ring 62, so that the outer conductive ring 68 and the inner ring 62 are in non-contact. It should be noted that the widths of the outer gap L1 and the inner gap L2 are preferably narrower, and are preferably from about 10 μm to 0.5 μm, which is the processing limit.

[0013] Further, as described above, the outer gap L1 between the outer ring 64 and the inner conductive ring 66 (flange portion 67b) and the inner gap L2 between the inner ring 62 and the outer conductive ring 68 (end face ring portion 69b) are impregnated with a conductive lubricant G. Through the conductive lubricant G, the inner conductive ring 66 and the outer ring 64 are electrically connected, and the outer conductive ring 68 and the inner ring 62 are electrically connected. The conductive lubricant G is not particularly limited as long as it is a conductive lubricant, and any material may be used. However, it is particularly preferable to use a well-known conductive grease obtained by mixing conductive powder such as tungsten or carbon into grease which is a lubricating oil. It is preferable that the conductive lubricant G is applied to the portion of the rolling elements 61 between the inner ring 62 and the outer ring 64, and the outer gap L1 and the inner gap L2 are impregnated with the conductive lubricant G by the rotation (rolling) of the rolling elements 61 accompanying the rotation of the inner ring 62 and the outer ring 64.

[0014] For example, a rotating member (not shown) is fixed to the inner conductive ring 66 (inner ring 62), and an electronic device provided on the rotating member is connected to the inner conductive ring 66 via an inner conductive line 20 such as a cable or a terminal. Further, for example, a fixing member (not shown) is fixed to the outer conductive ring 68 (outer ring 64), and an electronic device provided on the fixing member is connected to the outer conductive ring 68 via an outer conductive line 14 such as a cable or a terminal. Accordingly, electrical conduction between the electronic device on the fixing member side and the electronic device on the rotating member side is mainly achieved through two routes: a first route of the outer conductive line 14, the outer conductive ring 68, the outer ring 64, the conductive lubricant G, the inner conductive ring 66, and the inner conductive line 20, and a second route of the outer conductive line 14, the conductive lubricant G, the inner ring 62, the inner conductive ring 66, and the inner conductive line 20

[0015] Here, FIG. 3 shows a graph of the supply current to the motor (output of the conductor 60) from the conductor 60 when the inner conductive ring 66 (inner ring 62) of the conductor 60 is rotated by a motor, power is supplied to the motor through the conductor 60, and the rotation speed of the inner conductive ring 66 (inner ring 62) is varied within a range of 1000 rpm to 5000 rpm. In FIG. 3, the upper graph shows the temporal change of the supply current, and the lower graph shows the rotation speed of the motor at that time. It can be seen from FIG. 3 that a smooth current change at startup shown in region A and that the amount of current fluctuation remains substantially "0" even when the rotation speed fluctuates as shown in region B. It can be confirmed that the conductor 60 according to the present invention does not cause increase or variation in resistance value within the conductor 60 even when the inner conductive ring 66 (inner ring 62) rotates at 5000 rpm, and maintains favorable conductivity.

[0016] Furthermore, the conductor 60 according to the present invention may have a bearing on the inner circumference side of the inner ring 62 for a rotating shaft 10 that rotates independently of the inner ring 62 of the conductor 60. This bearing may be directly or via an insulator on the cylindrical portion 67a of the inner conductive ring 66, or a bearing member such as a bearing may be provided inside the inner ring 62 and used as the bearing. In this configuration, the conductor 60 according to the present invention can support a second rotating body that rotates independently of the first rotating body, in addition to the first rotating body fixed to the inner conductive ring 66. This makes it possible to use it in mechanical equipment that supports two rotating bodies (stator 40 and rotor 30), such as the electric motors 100a and 100b according to the present invention described later.

[0017] Although the conductor 60 described above is single-phase, as shown in Figure 4, a plurality of these conductors 60 may be installed coaxially in the radial direction to constitute the conductive device 80 according to the present invention. Here, Figure 4 is a schematic cross-sectional view of the conductive device 80 according to the present invention. In Figure 4, a three-phase conductive device 80 is shown, which has a first conductor 60A, a second conductor 60B, and a third conductor 60C arranged radially from the inner circumference. However, there is no particular limit to the number of conductors 60 in the conductive device 80; it may be two, four, six, nine, or any other number.

[0018] Furthermore, the conductors 60A, 60B, and 60C that constitute the conductive device 80 may be configured to rotate independently and individually. However, as shown in Figure 4, it is common to provide an inner ring holder 82 that holds all the inner conductive rings 66A, 66B, and 66C of the conductive device 80 in an insulated state, and an outer ring holder 84 that holds all the outer conductive rings 68A, 68B, and 68C in an insulated state, thereby connecting and rotating all the conductors 60A, 60B, and 60C.

[0019] Furthermore, the configuration described above, in which a bearing is provided on the inner circumference side of the conductor 60, may also be applied to the conductive device 80. In this case, a bearing for a rotating shaft 10 that rotates independently of the conductive device 80 is provided on the inner circumference side of the inner ring 62A of the first conductor 60A located at the innermost circumference of the conductive device 80. This bearing may be directly or via an insulator on the cylindrical portion 67a of the inner conductive ring 66A located at the innermost circumference, but it is preferable that it be the inner surface of the inner ring holder 82. Alternatively, a bearing member such as a bearing may be provided on the inner circumference side of the inner ring holder 82 and used as the bearing. In this configuration, in addition to the first rotating body fixed to the inner ring holder 82 of the conductive device 80, a second rotating body that rotates independently of the first rotating body can be pivotally supported inside the first rotating body. By applying this configuration to the electric motors 100a and 100b according to the present invention, which will be described later, it is possible to reduce the number of parts and save space.

[0020] Next, we will describe the electric motors 100a and 100b according to the present invention, which are equipped with a conductive device 80. Note that the electric motors 100a and 100b according to the present invention apply the conductive device 80 of the present invention to the invention described in [Patent Document 1].

[0021] First, the common configuration of the electric motors 100a and 100b according to the present invention will be described. The electric motors 100a and 100b according to the present invention, shown in Figures 5 and 6, include a three-phase conductive device 80 having a first conductor 60A, a second conductor 60B, and a third conductor 60C arranged radially from the inner circumference, an inner ring holder 82 that holds the inner conductive rings 66A, 66B, and 66C of the first conductor 60A, the second conductor 60B, and the third conductor 60C in an insulated state, a stator 40 fixed to the inner ring holder 82, a first field coil 42A, a second field coil 42B, and a third field coil 42C fixed to the stator 40, and inner conductive lines 20A, 20B, and 20C that connect the inner conductive rings 66A, 66B, and 66C to the field coils 42A, 42B, and 42C respectively, and the first The conductive device 80 includes an outer ring holder 84 that holds the outer conductive rings 68A, 68B, and 68C of the first conductor 60A, the second conductor 60B, and the third conductor 60C in an insulated state, a first power supply line 14A, a second power supply line 14B, and a third power supply line 14C that supply power to the outer conductive rings 68A, 68B, and 68C of the first conductor 60A, the second conductor 60B, and the third conductor 60C, respectively, a fixing body (fixed bearing part 12) that fixes the outer ring holder 84, a rotating shaft 10 with at least one end inserted into a bearing provided on the inner circumference side of the conductive device 80, a rotor 30 fixed to the rotating shaft 10, and magnetic members (field magnet 32, rotor core 36) provided on the rotor 30. Furthermore, the system includes a position information acquisition means (not shown) for acquiring the relative position of the magnetic members with respect to the field coils 42A, 42B, and 42C, and a control unit (not shown) that receives the rotational speed of the rotating shaft 10 (rotor 30) as input and controls the drive current to the field coils 42A, 42B, and 42C based on the position information from the position information acquisition means. There are no particular limitations on the position information acquisition means, and any known magnetic position detector such as a well-known position sensor or resolver-type angle measuring instrument, or a well-known optical position detector may be used. Alternatively, a position information acquisition means for acquiring the absolute position of the field coil 42 and a position information acquisition means for acquiring the absolute position of the magnetic members may be provided separately, and the control unit may calculate the relative position between the absolute position of the field coil 42 and the absolute position of the magnetic members.

[0022] Furthermore, the conductive device 80 of the present invention is provided between the fixed bearing portion 12, which acts as a stationary body, and the stator 40, and has the function of enabling the stator 40 to rotate while supplying a drive current from the fixed bearing portion 12 side to the field coils 42A, 42B, and 42C.

[0023] Furthermore, the rotating shaft 10 transmits rotational force to the driven body M. When the electric motors 100a and 100b according to the present invention are applied to hybrid vehicles such as HEVs, PHEVs, BEVs, and FCVs, electric vehicles, and fuel cell vehicles, the driven body M becomes a wheel or a reduction mechanism that rotates the wheel. At least one end of the rotating shaft 10 is inserted into a bearing provided on the inner circumference side of the conductive device 80, as described above. At this time, the rotating shaft 10 and the conductive device 80 are not physically fixed, and when there is no power supply to the field coils 42A, 42B, and 42C, the rotating shaft 10 and the stator 40 can rotate independently. Furthermore, a well-known anti-reverse mechanism 16, such as a one-way clutch, an electromagnetic clutch, or a mechanism using ratchet gears, is provided between the rotor 30 (rotating shaft 10) and the fixed bearing portion 12, and between the stator 40 and the fixed bearing portion 12, to restrict the rotation of the rotor 30 and stator 40 in the reverse direction. Additionally, the rotor 30 and the fixed bearing portion 12 may be fixed together, for example, when the driven body M is stopped, to prevent the rotor 30 from rotating.

[0024] Next, the configuration of the first embodiment of the electric motor 100a according to the present invention will be described. The first embodiment of the electric motor 100a shown in Figure 5 is an electric motor that operates on direct current and has a first field coil 42A, a second field coil 42B, and a third field coil 42C on the stator 40 side that function as an armature. The field coils 42A, 42B, and 42C each have a magnetic core on the winding core and are arranged in multiples, for example 12 × 3 sets = a total of 36, at regular intervals in the circumferential direction around the rotation shaft 10. Note that in Figure 5, only three of the field coils 42A, 42B, and 42C are shown for illustrative purposes.

[0025] Furthermore, two rotor discs 34 are fixed to the rotor 30 of the electric motor 100a, sandwiching the field coils 42A, 42B, and 42C on the stator 40 side. Multiple field magnets 32, acting as magnetic members, are fixed at equal intervals inside these rotor discs 34, facing the magnetic cores of the field coils 42A, 42B, and 42C on the stator 40 side. These field magnets 32 are permanent magnets that form a field flux for the field coils 42A, 42B, and 42C to rotate the rotor 30, and are arranged so that adjacent magnetic poles are opposite along the circumferential direction, that is, so that north and south poles appear alternately. In addition, metal magnets or sintered magnets may be used as field magnets 32, but it is particularly preferable to use rare earth magnets such as neodymium magnets, which have a large magnetic force. Note that although only two pairs of field magnets 32 are shown in Figure 5 for illustrative purposes, if there are, for example, 12 x 3 sets = 36 field coils 42A, 42B, and 42C, then six pairs of field magnets 32 will be provided, flanking the field coils 42A, 42B, and 42C.

[0026] One end of the first field coil 42A is connected to the inner conductive ring 66A of the first conductor 60A via the inner conductive line 20A. Another end of the second field coil 42B is connected to the inner conductive ring 66B of the second conductor 60B via the inner conductive line 20B. Another end of the third field coil 42C is connected to the inner conductive ring 66C of the third conductor 60C via the inner conductive line 20C. The other ends of the field coils 42A, 42B, and 42C are connected in a Y configuration.

[0027] Furthermore, the first power supply line 14A, the second power supply line 14B, and the third power supply line 14C extending from the equipment on the fixed bearing section 12 side are drawn in through the outer ring holder 84 of the conductive device 80, with the first power supply line 14A connecting to the outer conductive ring 68A of the first conductor 60A, the second power supply line 14B connecting to the outer conductive ring 68B of the second conductor 60B, and the third power supply line 14C connecting to the outer conductive ring 68C of the third conductor 60C. As a result, the outer conductive ring 68A or outer ring 64A of the first conductor 60A is electrically connected to the inner ring 62A or inner conductive ring 66A via the conductive lubricant G in the gaps L1 and L2, and is electrically connected to the first field coil 42A via the inner conductive line 20A. Furthermore, the outer conductive ring 68B or outer ring 64B of the second conductor 60B is electrically connected to the inner ring 62B or inner conductive ring 66B via the conductive lubricant G in the gaps L1 and L2, and is electrically connected to the second field coil 42B via the inner conductive line 20B. Also, the outer conductive ring 68C or outer ring 64C of the third conductor 60C is electrically connected to the inner ring 62C or inner conductive ring 66C via the conductive lubricant G in the gaps L1 and L2, and is electrically connected to the third field coil 42C via the inner conductive line 20C.

[0028] Then, the control unit of the electric motor 100a (not shown) controls the current value and flow direction of the drive current supplied to the first power supply line 14A, the second power supply line 14B, and the third power supply line 14C in order to perform the rotational operation requested by a higher-level control device, etc., based on the relative position of the rotor 30 (field magnet 32) with respect to the field coils 42A, 42B, and 42C from the position information acquisition means and the rotational speed of the rotating shaft 10 (rotor 30). These drive currents are supplied to the respective field coils 42A, 42B, and 42C via the conductors 60A, 60B, and 60C of the conductive device 80, generating a magnetic field, and the rotor 30 rotates at the torque and rotational speed instructed by the control unit due to the attractive and repulsive forces generated between this magnetic field and the field magnet 32.

[0029] Next, the configuration of the second embodiment of the electric motor 100b according to the present invention will be described with reference to Figure 6. The electric motor 100b of the second embodiment is an electric motor that operates on alternating current. First, the rotor 30 of the electric motor 100b has a rotor core 36 made of, for example, electromagnetic steel sheets bonded together in a cylindrical shape as a magnetic material. Inside the stator 40 facing the rotor core 36, a plurality of field coils 42A, 42B, and 42C, each equipped with a magnetic core, are installed so that the magnetic cores face the rotor core 36. For example, in the case of a three-phase AC electric motor 100b with U-phase, V-phase, and W-phase, the field coils 42A, 42B, and 42C corresponding to the U-phase, V-phase, and W-phase are arranged in that order. Furthermore, the conductive device 80 supplies a U-phase alternating current, instructed from the control unit of the electric motor 100b (not shown), to the first field coil 42A via the first power supply line 14A, through the outer conductive ring 68A or outer ring 64A of the first conductor 60A, the conductive lubricant G in the gap L1 or L2, the inner ring 62A or inner conductive ring 66A, and the inner conductive line 20A. In addition, it supplies a V-phase alternating current to the second field coil 42B via the second power supply line 14B, through the outer conductive ring 68B or outer ring 64B of the second conductor 60B, the conductive lubricant G in the gap L1 or L2, the inner ring 62B or inner conductive ring 66B, and the inner conductive line 20B. Furthermore, the W-phase alternating current is supplied from the third power supply line 14C to the third field coil 42C via the outer conductive ring 68C or outer ring 64C of the third conductor 60C, the conductive lubricant G in the gap L1 or L2, the inner ring 62C or inner conductive ring 66C, and the inner conductive line 20C. As a result, the magnetic field formed by the field coils 42A, 42B, and 42C rotates, and this rotating magnetic field causes eddy currents to flow down into the rotor core 36, acting as a Lorentz force and causing the rotor 30 to rotate.

[0030] Next, the characteristic operation of the electric motors 100a and 100b according to the present invention will be briefly described. First, when the power supply is off, both the rotor 30 and stator 40 of the electric motors 100a and 100b are in a stopped state. Next, when an output request is made to the rotating shaft 10, for example, by pressing the accelerator, the control unit causes a drive current to flow through the conductive device 80 to the field coils 42A, 42B, and 42C such that the rotor 30 rotates in the forward direction. As a result, the rotor 30 of the electric motors 100a and 100b rotates in the forward direction.

[0031] Next, if a request is made to decelerate the rotation of the rotating shaft 10 (rotor 30), for example by pressing the brake, the control unit causes a drive current to flow through the conductive device 80 to the field coils 42A, 42B, and 42C, which will decelerate the rotation of the rotor 30. As a result, the rotational speed of the rotor 30 decreases, and at the same time, a reaction force is generated between the rotor 30 and the stator 40, and this reaction force causes the stator 40 to rotate in the forward direction. Thus, the rotational force of the rotor 30 is converted into the rotation of the stator 40. Then, if a request for output to rotate the rotating shaft 10 in the forward direction is made again, for example by pressing the accelerator, the rotor 30 and the stator 40 are magnetically coupled, and the rotor 30 rotates in the same direction (forward direction) by the rotational force of the stator 40, and also rotates in the forward direction by the drive current from the field coils 42A, 42B, and 42C. Thus, in the electric motors 100a and 100b according to the present invention, the rotational force of the rotor 30 is stored as kinetic energy in the stator 40 during braking, etc., and this rotational force of the stator 40 is used as kinetic energy to rotate the rotor 30 during restart, etc. Therefore, energy loss is minimized, and the kinetic energy of the rotor 30 and stator 40 can be utilized to the maximum extent possible.

[0032] As described above, the conductor 60 and conductive device 80 according to the present invention utilize a rolling bearing, or so-called bearing, made of conductive metal, to achieve electrical conductivity between the stationary side and the rotating side. In this invention, an inner conductive ring 66 is fixed to the inner ring 62 that constitutes the bearing, and an outer conductive ring 68 is fixed to the outer ring 64. At this time, an outer gap L1 is provided between the inner conductive ring 66 and the outer ring 64, and an inner gap L2 is provided between the outer conductive ring 68 and the inner ring 62, so that they do not come into contact with each other. A conductive lubricant G is impregnated into these gaps L1 and L2, and the outer ring 64 and the outer conductive ring 68 are electrically connected to the inner ring 62 and the inner conductive ring 66 via this conductive lubricant G without contact. Therefore, the conductor 60 and conductive device 80 according to the present invention do not generate wear or frictional heat at the conductive parts during rotation. Furthermore, because conductivity is maintained in a non-contact state, stable conductivity can be maintained even at high speeds of rotation. This makes it possible to extend the lifespan of the components, improve reliability, and handle high-speed rotation. Furthermore, in a configuration where the bearing is located on the inner circumference side of the inner ring 62, the conductor 60 or conductive device 80 according to the present invention can also serve as the bearing on at least one side of the rotating shaft 10, thereby reducing component costs and enabling miniaturization and space saving.

[0033] Furthermore, the electric motors 100a and 100b using the conductive device 80 according to the present invention have the above-mentioned effects, and when used as motors in electric vehicles, for example, they can have high reliability, high durability, and a long lifespan even during long-term high-speed operation.

[0034] It should be noted that the configurations of the conductor 60, conductive device 80, and electric motors 100a and 100b shown in this example are merely examples, and the shape, dimensions, mechanism, design, number, etc. of each part can be modified without departing from the spirit of the present invention. Furthermore, the conductor 60 and conductive device 80 according to the present invention are not limited to the electric motors 100a and 100b in this example, but can be applied to conventional electric motors and generators of other structures, rotating lights, and other well-known rotating bodies. [Explanation of symbols]

[0035] 10 Rotation axis 14A, 14B, 14C power supply lines 30 rotors 32. Field magnet (magnetic component) 36. Rotor core (magnetic component) 40 stata 42A, 42B, 42C Field coils 60, 60A, 60B, 60C conductor 61 Rolling element 62 Inner Ring 64 Outer ring 66, 66A, 66B, 66C Inner conductive ring 68, 68A, 68B, 68C Outer conductive ring 80 Conductive devices 82 Inner ring holder 84 Outer ring holder 100a, 100b electric motor G Conductive lubricant L1 outer gap L2 internal gap

Claims

1. An inner ring made of conductive metal, An outer ring made of a conductive metal, Multiple rolling elements are installed between the outer circumferential surface of the inner ring and the inner circumferential surface of the outer ring to rotate either the outer ring or the inner ring. An inner conductive ring that is conductive, does not contact the outer ring, maintains a predetermined outer gap, and is electrically connected to the inner ring, An outer conductive ring that is conductive, does not contact the inner ring, maintains a predetermined internal gap, and is electrically connected to the outer ring, The inner and outer gaps are impregnated with a conductive lubricant, A conductor characterized by having an inner conductive ring and an outer conductive ring electrically connected via the inner ring, outer ring, and conductive lubricant.

2. The conductive device according to claim 1, characterized in that a conductive lubricant is applied to the rolling elements, and the rotation of the rolling elements impregnates the outer and inner gaps with the conductive lubricant.

3. The conductor according to claim 1, characterized in that it has a bearing for a rotating shaft that rotates separately from the inner ring on the inner circumference side of the inner ring.

4. A conductive device characterized by having a plurality of conductors described in claim 1 installed coaxially in the radial direction.

5. A conductive device according to claim 4, comprising a first conductor, a second conductor, and a third conductor arranged radially from the inner circumferential side, An inner ring holder that holds the inner conductive rings of the first conductor, the second conductor, and the third conductor in an insulating state, A stator fixed to the inner ring holder, A first field coil fixed to the stator and to which power is input via the inner conductive ring of the first conductor, A second field coil fixed to the stator and to which power is input via the inner conductive ring of the second conductor, A third field coil fixed to the stator and to which power is input via the inner conductive ring of the third conductor, An outer ring holder that holds the outer conductive rings of the first conductor, the second conductor, and the third conductor in an insulating state, A first power supply line that supplies power to the outer conductive ring of the first conductor, A second power supply line that supplies power to the outer conductive ring of the second conductor, A third power supply line that supplies power to the outer conductive ring of the third conductor, A rotating shaft is provided, with at least one end inserted into a bearing located on the inner circumference side of the conductive device, and rotating independently of the conductive device. A rotor fixed to the aforementioned rotating shaft, An electric motor characterized by having a magnetic member provided on the rotor that rotates the rotor by the magnetic field generated by the first field coil, the second field coil, and the third field coil.

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