Electric power transmission device and motor apparatus

Abstract

An electric power transmission device according to one embodiment of the present invention comprises: a rotating member that is connected to a shaft and is capable of turning in the circumferential direction of the shaft; a first winding that is provided to the rotating member and is wound along the circumferential direction; a second winding that is provided at a position different from the position where the rotating member is provided in the axial direction of the shaft and that is wound along the circumferential direction; and a magnetic core that is provided in a manner surrounding the rotating member and the second winding, and that has a first opening provided in a surface located in a direction away from the shaft in a first direction intersecting the axial direction.

Description

Power transmission device and motor device

[0001] The present invention relates to a power transmission device that transmits power in a contactless manner, and to a motor apparatus provided with such a power transmission device.

[0002] For example, there is an electrically excited synchronous motor (EESM), which has a stator with windings and a rotor with windings. This motor can improve its efficiency by changing the current flowing through the windings on the rotor according to the rotational speed of the motor.

[0003] There are devices capable of transmitting power between a stator and a rotor. For example, Patent Document 1 discloses a power transmission device capable of supplying power from a stator to a rotor in a non-contact manner.

[0004] U.S. Pat. No. 5,637,973

[0005] In such a power transmission device, for example, the amount of heat generated increases as the amount of power transmitted increases, and therefore, power transmission devices are expected to be able to easily dissipate heat.

[0006] It is desirable to provide a power transfer device and a motor apparatus that can facilitate heat dissipation.

[0007] A power transfer device according to one embodiment of the present invention includes a rotating member, a first winding, a second winding, and a magnetic core. The rotating member is connected to a shaft and is rotatable in a circumferential direction of the shaft. The first winding is provided on the rotating member and wound in the circumferential direction. The second winding is provided at a position in the axial direction of the shaft different from the position at which the rotating member is provided and wound in the circumferential direction. The magnetic core is provided to surround the rotating member and the second winding, and has a first opening provided on a surface facing away from the shaft in a first direction intersecting the axial direction.

[0008] A motor device according to one embodiment of the present invention includes a motor, a shaft, an inverter, a rotating member, a first winding, a second winding, a magnetic core, and a rectifier circuit. The motor includes a motor stator including a first motor magnetic core and a first motor winding, and a motor rotor including a second motor magnetic core and a second motor winding. The shaft is connected to the motor rotor. The rotating member is connected to the shaft and is rotatable in a circumferential direction of the shaft. The first winding is provided on the rotating member and wound circumferentially. The second winding is provided at a position on the shaft axially different from the position at which the rotating member is provided, wound circumferentially, and connected to the inverter. The magnetic core is provided to surround the rotating member and the second winding, and has a first opening provided on a surface facing away from the shaft in a first direction intersecting the axial direction. The rectifier circuit is provided in a path connecting the first winding and the second motor winding.

[0009] According to a power transmission device and a motor apparatus according to an embodiment of the present invention, heat can be easily dissipated.

[0010] FIG. 1 is a block diagram illustrating an example configuration of a motor apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view illustrating an example configuration of the power transmission device shown in FIG. 1. FIG. 3 is an explanatory diagram illustrating an example configuration of the power transmission device shown in FIG. 2. FIG. 4 is a cross-sectional view illustrating an example configuration of the power transmission device shown in FIG. 2. FIG. 5 is an explanatory diagram illustrating an example configuration of two substrates shown in FIG. 2. FIG. 6 is an explanatory diagram illustrating an example configuration of a stator shown in FIG. 2. FIG. 7 is an explanatory diagram illustrating an example of magnetic flux in the power transmission device shown in FIG. 4. FIG. 8 is a perspective view illustrating an example configuration of a power transmission device according to a modified example. FIG. 9 is an explanatory diagram illustrating an example configuration of the power transmission device shown in FIG. 8. FIG. 10 is an explanatory diagram illustrating an example configuration of a power transmission device according to another modified example. FIG. 11 is a cross-sectional view illustrating an example configuration of a power transmission device according to another modified example. FIG. 12 is an explanatory diagram illustrating an example of magnetic flux in the power transmission device shown in FIG. 11. FIG. 13 is a cross-sectional view illustrating an example configuration of a power transmission device according to another modified example. FIG. 14 is an explanatory diagram illustrating an example configuration of a power transmission device according to another modified example. Fig. 15 is a perspective view illustrating a configuration example of a power transmission device according to another modified example Fig. 16 is an explanatory diagram illustrating the configuration example of the power transmission device illustrated in Fig. 15 .

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0012] <Embodiment> [Configuration Example] Fig. 1 shows an example configuration of a motor apparatus 1 equipped with a power transmission device according to an embodiment of the present invention. The motor apparatus 1 is connected to an external control device 8 and a DC power supply 9. The external control device 8 is configured to instruct the motor apparatus 1 on a rotation speed. The DC power supply 9 is configured to supply DC power to the motor apparatus 1. The motor apparatus 1 is configured to generate driving force, which is mechanical energy, using the DC power supplied from the DC power supply 9 based on instructions from the external control device 8. The motor apparatus 1 includes a drive unit 10 and a motor 50.

[0013] The drive unit 10 is configured to drive the motor 50. The drive unit 10 includes inverters 11 and 12, a power transmission device 20, a blower 13, a rectifier circuit 14, and a control circuit 19.

[0014] The inverter 11 is configured to convert the DC power supplied from the DC power supply 9 into three-phase (U-phase, V-phase, W-phase) AC power based on instructions from the control circuit 19. The inverter 11 then supplies this three-phase AC power to a winding 51B (described later) of a stator 51 of the motor 50.

[0015] The inverter 12 is configured to convert the DC power supplied from the DC power supply 9 into single-phase AC power based on an instruction from the control circuit 19. The inverter 12 then supplies this AC power to a winding 36 (described later) of a stator 30 of the power transmission device 20.

[0016] The power transmission device 20 is configured to supply AC power to the rectifier circuit 14 by contactless transmission. The power transmission device 20 includes a stator 30, a rotor 40, and a shaft 24.

[0017] 2 and 3 show an example configuration of the power transmission device 20. Fig. 3 also shows a cross-sectional structure of the power transmission device 20 as viewed in the direction of arrows III-III. Fig. 4 shows an example cross-sectional structure of the power transmission device 20 in a plane including the rotation axis AZ. Fig. 5 shows an example configuration of a substrate 34 (described later) of the stator 30 and a substrate 41 (described later) of the rotor 40.

[0018] The stator 30 is fixed to a housing (not shown) of the motor device 1. As shown in FIGS.

[0019] The magnetic core 31 is made of a magnetic material such as ferrite. As shown in FIGS. 2 to 4, the magnetic core 31 is configured to surround the substrate 34 and the rotor 40. The magnetic core 31 has a magnetic core 31A and a magnetic core 31B. The magnetic core 31A and the magnetic core 31B are arranged in this order in the Z direction. Here, the Z direction is the axial direction of the rotation axis AZ, as shown in FIG. 1, and is the direction from the motor 50 to the power transmission device 20. The magnetic core 31 is provided with a through hole 33 for passing the shaft 24 therethrough.

[0020] As shown in FIG. 3 , the magnetic core 31A has a circular shape in the XY plane intersecting the axial direction of the rotation axis AZ, with both ends in the Y direction and the opposite direction cut off. The magnetic core 31A has convex portions 31C at each of its ends in the X direction and the opposite direction that protrude in the direction in which the magnetic core 31B is provided. Each of the two convex portions 31C of the magnetic core 31A has an arc shape in the XY plane. The magnetic core 31B has a shape similar to that of the magnetic core 31A. Like the magnetic core 31A, the magnetic core 31B has convex portions 31C at each of its ends in the X direction and the opposite direction that protrude in the direction in which the magnetic core 31A is provided. The magnetic cores 31A and 31B are connected so that the two convex portions 31C of the magnetic core 31A and the two convex portions 31C of the magnetic core 31B are in contact with each other. In this way, the magnetic core 31 has an internal cavity, and openings 120 that connect the internal cavity of the magnetic core 31 to the outside are provided at both ends in the Y direction and the opposite direction.

[0021] The substrate 34 is, for example, a printed circuit board (PCB). In this example, as shown in FIG. 4, the substrate 34 is provided on the surface of the magnetic core 31A facing the magnetic core 31B. As shown in FIGS. 3 and 5, the substrate 34 has a ring shape. As shown in FIG. 5, the substrate 34 is provided with a winding 36. The substrate 34 has a wiring lead-out portion 34A provided at an end of the substrate 34 on the opposite side in the Y direction. Two pattern wirings are provided on this wiring lead-out portion 34A, which lead both ends of the winding 36 to the outside. In FIG. 5, these two pattern wirings are indicated by thick lines. The winding 36 is connected to the inverter 12 via the two pattern wirings on the wiring lead-out portion 34A.

[0022] The winding 36 is configured using a pattern wiring provided on the substrate 34, and is wound multiple times circumferentially around the rotation axis AZ. In Fig. 5, the area of ​​the substrate 34 where the winding 36 is provided is indicated by hatching. The winding 36 may be provided on one or both of the two surfaces of the substrate 34. Furthermore, if the substrate 34 is a multilayer substrate, the winding 36 may be configured using a pattern wiring inside the substrate 34. The winding 36 is connected to the inverter 12 via two pattern wirings in a wiring lead-out portion 34A of the substrate 34.

[0023] Fig. 6 shows the position of the winding 36 in the XY plane. In Fig. 6, the magnetic core 31A and the substrate 34 are drawn overlapping each other. In the XY plane, both ends (portion W1) of the region where the winding 36 is provided, in the Y direction and in the opposite direction, extend beyond the region of the magnetic core 31. In other words, because the width of the magnetic core 31A in the Y direction is narrow, part of the region where the winding 36 is provided extends beyond the region of the magnetic core 31.

[0024] The rotor 40 is configured to rotate about a rotation axis AZ. As shown in Fig. 4, the rotor 40 is disposed so as to be sandwiched between the magnetic cores 31A and 31B of the stator 30 in the Z direction, and is fixed to the shaft 24. As shown in Figs. 2 to 5, the rotor 40 has a substrate 41 and windings 42.

[0025] The substrate 41 is, for example, a printed circuit board. The substrate 41 is provided at a position in the Z direction different from the position at which the substrate 34 of the stator 30 is provided. The substrate 41 has a circular shape as shown in FIG. 5. In this example, the size of the substrate 41 is approximately the same as the size of the substrate 34 of the stator 30. The substrate 41 is provided with a winding 42 as shown in FIG. 5.

[0026] The winding 42 is configured using a pattern wiring provided on the substrate 41 and is wound multiple times circumferentially around the rotation axis AZ. In FIG. 5 , the region of the substrate 41 where the winding 42 is provided is indicated by a shaded area. The winding 42 may be provided on one or both of the two surfaces of the substrate 41. Furthermore, if the substrate 41 is a multilayer substrate, the winding 42 may be configured using pattern wiring inside the substrate 41. As shown in FIG. 5 , in this example, the region of the substrate 41 where the winding 42 is provided is substantially the same as the region of the substrate 34 of the stator 30 where the winding 36 is provided. However, this is not a limitation, and the region of the substrate 41 where the winding 42 is provided may be different from the region of the substrate 34 where the winding 36 is provided. As with the winding 36 ( FIG. 6 ), both ends of the region where the winding 42 is provided, in the Y direction and in the opposite direction, protrude from the region of the magnetic core 31. Both ends of the winding 42 are connected to the rectifier circuit 14 via two pattern wirings provided on the substrate 41 and a wiring (not shown) provided on the shaft 24. In Fig. 5, these two pattern wirings are indicated by thick lines.

[0027] The shaft 24 is connected to the rotor 52 of the motor 50 and is configured to rotate about the rotation axis AZ in response to the driving force generated by the motor 50. The shaft 24 may be directly connected to the rotor 52 of the motor 50, or may be indirectly connected via another component. The shaft 24 may also be formed integrally with the rotor 52 of the motor 50. In this example, the shaft 24 is configured to penetrate the power transmission device 20 in the Z direction as shown in FIGS. 1 and 2 , but the present invention is not limited to this and may not protrude from the power transmission device 20 in the Z direction.

[0028] With this configuration, the power transmission device 20 transmits AC power supplied from the inverter 12 from the stator 30 to the rotor 40 as the shaft 24 rotates about the rotation axis AZ, and supplies the transmitted AC power to the rectifier circuit 14. The power transmission device 20 is also called a rotary transformer.

[0029] In this example, the power transmission device 20 is arranged such that the magnetic core 31A, the substrate 34, the substrate 41, and the magnetic core 31B are aligned in this order in the Z direction, but this is not limited to this. Alternatively, the power transmission device 20 may be aligned in the opposite direction in the Z direction. In this case, the magnetic core 31B, the substrate 41, the substrate 34, and the magnetic core 31A are aligned in this order in the Z direction.

[0030] The blower 13 ( FIG. 1 ) is configured to cool the power transmission device 20 by blowing air toward the power transmission device 20. The blower 13 blows air toward, for example, an opening 120 in the power transmission device 20. This causes air to flow in the Y direction through the cavity inside the power transmission device 20. In this way, the blower 13 can cool, by air cooling, for example, the magnetic core 31, the winding 36 on the substrate 34, and the winding 42 on the substrate 41 in the power transmission device 20.

[0031] Rectifier circuit 14 is configured to rectify the AC power supplied from windings 42 of rotor 40 and supply the rectified power to windings 52B (described below) of rotor 52 of motor 50. Although not shown, rectifier circuit 14 is connected to shaft 24. That is, since windings 42 and rotor 52 of motor 50 are connected to shaft 24, rectifier circuit 14 is also connected to shaft 24. Note that in this example, the power rectified by rectifier circuit 14 is supplied directly to winding 52B, but this is not limiting. Instead, for example, the power rectified by rectifier circuit 14 may be supplied to winding 52B via a stabilizing circuit including a capacitor.

[0032] The control circuit 19 is configured to control the operation of the inverters 11 and 12 based on instructions from the external control device 8 and a control signal indicating the rotational speed supplied from the motor 50. Specifically, the control circuit 19 controls the operation of the inverter 11 based on instructions from the external control device 8 and a control signal indicating the rotational speed of the motor 50, thereby controlling the rotational speed of the motor 50. The control circuit 19 also controls the operation of the inverter 12 based on the control signal indicating the rotational speed supplied from the motor 50, thereby controlling the strength of the magnetic field generated by the rotor 52 of the motor 50. Specifically, for example, the control circuit 19 strengthens the magnetic field generated by the rotor 52 of the motor 50 when the rotational speed of the motor 50 is slow, and weakens the magnetic field generated by the rotor 52 of the motor 50 when the rotational speed of the motor 50 is fast.

[0033] The motor 50 is a wound field type synchronous motor and includes a stator 51, a rotor 52, and a sensor 53.

[0034] The stator 51 is a so-called stator, and is fixed to a housing (not shown) of the motor 50. The stator 51 has a magnetic core 51A and a winding 51B. The winding 51B is supplied with three-phase (U-phase, V-phase, and W-phase) AC power generated by the inverter 11.

[0035] The rotor 52 is a so-called rotor and is configured to rotate about a rotation axis AZ. The rotor 52 has a magnetic core 52A and a winding 52B. A signal rectified by the rectifier circuit 14 is supplied to the winding 52B.

[0036] The sensor 53 is configured to detect the rotation speed of the rotor 52. The sensor 53 is then configured to provide the control circuit 19 with a control signal indicative of the rotation speed of the rotor 52.

[0037] With this configuration, motor device 1 controls the rotation speed of motor 50 based on three-phase (U-phase, V-phase, W-phase) AC power generated by inverter 11, and controls the magnetic field generated by rotor 52 of motor 50 based on single-phase AC power generated by inverter 12. For example, motor device 1 strengthens the magnetic field generated by rotor 52 of motor 50 when the rotation speed of motor 50 is slow, and weakens the magnetic field generated by rotor 52 of motor 50 when the rotation speed of motor 50 is fast. This allows motor device 1 to increase the efficiency of motor 50 over a wide range of rotation speeds.

[0038] Here, shaft 24 corresponds to a specific example of "shaft" in an embodiment of the present disclosure. Substrate 41 corresponds to a specific example of "rotating member" in an embodiment of the present disclosure. Winding 42 corresponds to a specific example of "first winding" in an embodiment of the present disclosure. Winding 36 corresponds to a specific example of "second winding" in an embodiment of the present disclosure. Magnetic core 31 corresponds to a specific example of "magnetic core" in an embodiment of the present disclosure. Opening 120 corresponds to a specific example of "first opening" and "second opening" in an embodiment of the present disclosure.

[0039] The stator 51 corresponds to a specific example of a "motor stator" in an embodiment of the present disclosure. The magnetic core 51A corresponds to a specific example of a "first motor magnetic core" in an embodiment of the present disclosure. The winding 51B corresponds to a specific example of a "first motor winding" in an embodiment of the present disclosure. The rotor 52 corresponds to a specific example of a "motor rotor" in an embodiment of the present disclosure. The magnetic core 52A corresponds to a specific example of a "second motor magnetic core" in an embodiment of the present disclosure. The winding 52B corresponds to a specific example of a "second motor winding" in an embodiment of the present disclosure. The inverter 12 corresponds to a specific example of an "inverter" in an embodiment of the present disclosure. The rectifier circuit 14 corresponds to a specific example of a "rectifier circuit" in an embodiment of the present disclosure. The blower 13 corresponds to a specific example of a "cooling device" in an embodiment of the present disclosure.

[0040] [Operation and Function] Next, the operation and function of the motor device 1 of this embodiment will be described.

[0041] (Overview of Overall Operation) The control circuit 19 controls the operation of the inverters 11 and 12 based on instructions from the external control device 8 and a control signal indicating the rotational speed supplied from the motor 50. The inverter 11 converts the DC power supplied from the DC power supply 9 into three-phase (U-phase, V-phase, and W-phase) AC power based on instructions from the control circuit 19 and supplies this three-phase AC power to the windings 51B of the stator 51 of the motor 50. The inverter 12 converts the DC power supplied from the DC power supply 9 into single-phase AC power based on instructions from the control circuit 19 and supplies this AC power to the windings 36 of the stator 30 of the power transmission device 20. The power transmission device 20 supplies the AC power to the rectifier circuit 14 via contactless transmission. The rectifier circuit 14 rectifies the AC power supplied from the windings 42 of the rotor 40 and supplies the rectified power to the windings 52B of the rotor 52 of the motor 50. The motor 50 generates a driving force, which is mechanical energy, based on the three-phase (U-phase, V-phase, W-phase) AC power supplied from the inverter 11. This causes the shaft 24 to rotate about the rotation axis AZ. The sensor 53 of the motor 50 supplies a control signal indicating the rotation speed of the motor 50 to the control circuit 19.

[0042] [Operation and Function] Next, the operation and function of the power transmission device 20 of the present embodiment will be described.

[0043] The windings 36 of the stator 30 of the power transmission device 20 are supplied with AC power from the inverter 12. The rotor 40 rotates around a rotation axis AZ in, for example, a circumferential direction A shown in FIG.

[0044] 7 shows a cross-sectional view of the stator 30 and the rotor 40 of the power transmission device 20. The area of ​​the stator 30 where the windings 36 are provided is shown shaded. The area of ​​the rotor 40 where the windings 42 are provided is also shown shaded.

[0045] The windings 36 of the stator 30 generate a magnetic field based on the AC power supplied from the inverter 12. The portion of the magnetic core 31A close to the shaft 24 and the portion of the magnetic core 31B close to the shaft 24 are magnetically coupled to each other. As a result, in the power transfer device 20, a magnetic path MP is generated that passes through the magnetic cores 31A and 31B, as shown in FIG. 7 .

[0046] The windings 42 of the rotor 40 generate AC power based on the magnetic field in this magnetic path MP and supply the generated AC power to the rectifier circuit 14. In this way, the power transmission device 20 can supply AC power to the rectifier circuit 14 by contactless transmission.

[0047] In this way, in the power transmission device 20, power is transmitted by non-contact transmission, which can improve reliability compared to when power is transmitted by contact transmission using, for example, slip rings and brushes.

[0048] The rectifier circuit 14 rectifies the AC power supplied from the windings 42 of the rotor 40 and supplies the rectified power to the windings 52B of the rotor 52 of the motor 50. This causes a magnetic field to be generated in the rotor 52 of the motor 50. For example, the control circuit 19 strengthens the magnetic field generated by the rotor 52 of the motor 50 when the rotation speed of the motor 50 is slow, and weakens the magnetic field generated by the rotor 52 of the motor 50 when the rotation speed of the motor 50 is fast. This allows the motor device 1 to increase the efficiency of the motor 50 over a wide range of rotation speeds.

[0049] Thus, the power transmission device 20 includes a rotating member (substrate 41) connected to the shaft 24 and rotatable in the circumferential direction of the shaft 24, a first winding (winding 42) provided on the rotating member (substrate 41) and wound circumferentially, a second winding (winding 36) provided in a position different from the position of the rotating member (substrate 41) in the axial direction of the shaft 24 and wound circumferentially, and a magnetic core 31 provided to surround the rotating member (substrate 41) and the second winding (winding 36), and having a first opening (opening 120 provided in the Y direction) provided on a surface facing away from the shaft in a first direction (Y direction) intersecting the axial direction. This allows the power transmission device 20 to dissipate heat from the magnetic core 31, the winding 36 on the substrate 34, and the winding 42 on the substrate 41. That is, for example, if the magnetic core 31 were configured without the openings 120, heat generated by the windings 36, 42, for example, would accumulate in the cavity inside the magnetic core 31, resulting in poor heat dissipation. On the other hand, in the power transmission device 20, the openings 120 are provided in the magnetic core 31, so heat is less likely to accumulate in the cavity inside the magnetic core 31. As a result, the power transmission device 20 can dissipate heat more easily.

[0050] Furthermore, in the power transmission device 20, the opening 120 is provided, which makes it easier to arrange wiring connecting the winding 36 provided inside the magnetic core 31 and the inverter 12. That is, for example, if the magnetic core 31 is configured without the opening 120, it would be difficult to lead the winding 36 provided inside the magnetic core 31 to the inverter 12. On the other hand, in the power transmission device 20, the opening 120 is provided in the magnetic core 31, which makes it easier to lead the winding 36 from the inside to the outside of the magnetic core 31 and connect it to the inverter 12. Therefore, in the power transmission device 20, it is easier to arrange wiring connecting the winding 36 and the inverter 12.

[0051] Furthermore, in the power transfer device 20, the magnetic core 31 has a second opening (opening 120 provided in the direction opposite to the Y direction) provided on a surface facing away from the shaft 24 in a second direction opposite to the first direction (Y direction). This allows air to flow more easily in the Y direction in the cavity inside the magnetic core 31. As a result, the power transfer device 20 can dissipate heat more easily.

[0052] In particular, the motor device 1 is provided with a cooling device (air blower 13) that can supply a cooling medium (air in this example) toward the first opening (opening 120) of the magnetic core 31. This allows the motor device 1 to send, for example, low-temperature air into the interior of the power transmission device 20. As a result, the power transmission device 20 can cool the magnetic core 31, the winding 36 on the substrate 34, and the winding 42 on the substrate 41.

[0053] Furthermore, in the power transmission device 20, the rotating member (substrate 41) includes a printed circuit board. The first winding (winding 42) is a pattern wiring provided on the printed circuit board. This allows the rotor 40 to be lighter than when the rotor 40 is configured using an iron core, for example, and therefore reduces the rotational moment and inertia force.

[0054] Furthermore, in the power transmission device 20, a portion of the rotating member (substrate 41) protrudes from the first opening (opening 120) of the magnetic core 31 in a first direction (Y direction) in a plane intersecting the axial direction. This allows the size of the magnetic core 31 to be reduced in the power transmission device 20. That is, because the winding 42 is a pattern wiring provided on the substrate 41, increasing the number of turns of the winding 42 increases the diameter of the substrate 41. Therefore, for example, if a portion of the substrate 41 is configured not to protrude from the opening 120 of the magnetic core 31, the size of the magnetic core 31 increases. In this case, for example, the size of the power transmission device 20 increases. Furthermore, the cost of the magnetic core 31 increases. On the other hand, in the power transmission device 20, the magnetic core 31 protrudes from the opening 120 of the magnetic core 31, allowing the size of the magnetic core 31 to be reduced. This allows the size of the power transmission device 20 to be reduced, and the cost of the magnetic core 31 to be reduced.

[0055] In particular, in the power transmission device 20, a portion of the first winding (winding 42) provided on the rotating member (substrate 41) protrudes from the first opening (opening 120) of the magnetic core 31 in a first direction (Y direction) in a plane intersecting the axial direction. This allows the size of the magnetic core 31 to be reduced, and therefore, for example, the size of the power transmission device 20 can be reduced, and the cost of the magnetic core 31 can be reduced.

[0056] [Effects] As described above, this embodiment includes a rotating member connected to a shaft and rotatable in the circumferential direction of the shaft, a first winding provided on the rotating member and wound in the circumferential direction, a second winding provided in an axial direction of the shaft at a position different from the position at which the rotating member is provided and wound in the circumferential direction, and a magnetic core provided to surround the rotating member and the second winding and having a first opening provided on a surface facing away from the shaft in a first direction intersecting the axial direction. This facilitates heat dissipation.

[0057] [Variation 1] In the above embodiment, as shown in FIG. 3 , openings 120 are provided at both ends of magnetic core 31 in the Y direction and the opposite direction, but this is not limited to this. Alternatively, for example, as shown in FIGS. 8 and 9 , openings 120 may be provided at only one of both ends of magnetic core 31 in the Y direction and the opposite direction. In this example, as shown in FIG. 9 , magnetic core 31A has a shape in the XY plane that is like a circle with the end opposite to the Y direction cut off. Magnetic core 31A has a convex portion 31C at the end other than the cut-off portion in the XY plane that protrudes in the direction toward magnetic core 31B. This convex portion 31C has an arc shape in the XY plane. Magnetic core 31B has a shape similar to magnetic core 31A. Like magnetic core 31A, magnetic core 31B has a convex portion 31C at the end other than the cut-off portion that protrudes in the direction toward magnetic core 31A. The magnetic core 31A and the magnetic core 31B are connected so that the convex portion 31C of the magnetic core 31A contacts the convex portion 31C of the magnetic core 31B, thereby providing the opening 120 only at the end of the magnetic core 31 opposite to the Y direction.

[0058] [Variation 2] In the above embodiment, as shown in FIG. 4, the position of the inner side surface of the magnetic core 31A facing the shaft 24 and the position of the inner side surface of the substrate 34 facing the shaft 24 are aligned. However, this is not limited to this. Alternatively, as shown in FIGS. 10 and 11, these positions do not have to be aligned. In this example, the magnetic core 31A has a protrusion 31D at its inner end that protrudes in the direction in which the magnetic core 31B is provided. This protrusion 31D has a ring shape in the XY plane. The substrate 34 is fitted around the ring-shaped protrusion 31D. In this configuration, a magnetic path MP is generated that passes through this protrusion 31D, as shown in FIG. 12.

[0059] [Variation 3] In the above embodiment, the windings 36 of the stator 30 are configured using pattern wiring provided on the substrate 34, but this is not limited to this. Instead, for example, the windings 36 may be configured using conductor wire or copper plate. When conductor wire is used, for example, Litz wire may be used. When the windings 36 are configured using conductor wire, for example, the windings 36 may be wound around a bobbin 37 as shown in FIG. 13. By using the substrate 34 as in the above embodiment, it is possible to easily adjust the center of gravity of the substrate 34 to coincide with the rotation axis AZ, thereby suppressing eccentricity.

[0060] 5, the winding 36 is wound in a circular shape on the substrate 34, but this is not limiting and the winding may alternatively be wound in a polygonal shape, for example. Similarly, the winding 42 is wound in a circular shape on the substrate 41, but this is not limiting and the winding may alternatively be wound in a polygonal shape, for example.

[0061] [Variation 5] In the above embodiment, the substrate 34 of the stator 30 has a circular ring shape, but this is not limited to this and may have a non-circular ring shape, for example, as shown in Fig. 14. In this example, the outer shape of the substrate 34 is a rectangular ring shape.

[0062] [Variation 6] In the above embodiment, as shown in Figures 2 and 3, the magnetic cores 31A and 31B have a circular shape in the XY plane, with both ends in the Y direction and the opposite direction cut off. However, this is not limited to this. Alternatively, as shown in Figures 15 and 16, for example, the magnetic cores 31A and 31B may have a rectangular shape in the XY plane. In this case, each of the two protrusions 31C of the magnetic core 31A has a rectangular shape in the XY plane. The same applies to the magnetic core 31B. The magnetic cores 31A and 31B are connected so that the two protrusions 31C of the magnetic core 31A are in contact with the two protrusions 31C of the magnetic core 31B. In this way, the magnetic core 31 has an internal cavity, and openings 120 are provided on both sides in the Y direction, connecting the internal cavity of the magnetic core 31 to the outside.

[0063] [Variation 7] In the above embodiment, the air blower 13 is provided and the power transmission device 20 is cooled by air cooling using air as a cooling medium, but the cooling medium is not limited to air. Instead, for example, the power transmission device 20 may be cooled by oil cooling using oil as a cooling medium, or by water cooling using water as a cooling medium.

[0064] [Other Modifications] Two or more of these modifications may be combined.

[0065] Although the present invention has been described above by way of embodiments and modifications, the present invention is not limited to these embodiments and can be modified in various ways.

[0066] For example, the shapes of the magnetic core 31, the substrate 34, and the substrate 41 shown in the above embodiments are merely examples, and are not limited to the disclosed shapes.

[0067] The effects described in this specification are merely examples, and the effects of the present disclosure are not limited to the effects described in this specification. Therefore, other effects may be obtained with respect to the present disclosure.

[0068] Furthermore, the present disclosure may take the following aspects.

[0069] (1) A power transmission device comprising: a rotating member connected to a shaft and rotatable in a circumferential direction of the shaft; a first winding provided on the rotating member and wound along the circumferential direction; a second winding provided in an axial direction of the shaft at a position different from a position at which the rotating member is provided and wound along the circumferential direction; and a magnetic core provided to surround the rotating member and the second winding, the magnetic core having a first opening provided on a surface facing away from the shaft in a first direction intersecting the axial direction. (2) The power transmission device according to (1), wherein the magnetic core has a second opening provided on a surface facing away from the shaft in a second direction opposite to the first direction. (3) The power transmission device according to (1) or (2), wherein the rotating member includes a printed circuit board, and the first winding is pattern wiring provided on the printed circuit board. (4) The power transfer device according to any one of (1) to (3), wherein a portion of the rotating member protrudes from the first opening of the magnetic core in the first direction within a plane intersecting the axial direction. (5) The power transfer device according to (4), wherein a portion of the first winding provided on the rotating member protrudes from the first opening of the magnetic core in the first direction within a plane intersecting the axial direction. (6) A motor device comprising: a motor having a motor stator including a first motor magnetic core and a first motor winding, and a motor rotor including a second motor magnetic core and a second motor winding; a shaft connected to the motor rotor; an inverter; a rotating member connected to the shaft and rotatable in a circumferential direction of the shaft; a first winding provided on the rotating member and wound along the circumferential direction; a second winding provided in an axial direction of the shaft at a position different from a position at which the rotating member is provided, wound along the circumferential direction, and connected to the inverter; a magnetic core provided so as to surround the rotating member and the second winding, and having a first opening provided on a surface facing away from the shaft in a first direction intersecting the axial direction; and a rectifier circuit provided in a path connecting the first winding and the second motor winding.(7) The motor device according to (6), further comprising a cooling device capable of supplying a cooling medium toward the first opening of the magnetic core.

Claims

1. A power transmission device comprising: a rotating member connected to a shaft and rotatable in a circumferential direction of the shaft; a first winding provided on the rotating member and wound along the circumferential direction; a second winding provided in an axial direction of the shaft at a position different from a position at which the rotating member is provided and wound along the circumferential direction; and a magnetic core provided so as to surround the rotating member and the second winding, and having a first opening provided on a surface facing away from the shaft in a first direction intersecting the axial direction.

2. The power transfer device according to claim 1, wherein the magnetic core has a second opening provided on a surface facing away from the shaft in a second direction opposite to the first direction.

3. The power transfer device according to claim 1, wherein the rotating member includes a printed circuit board, and the first winding is a pattern wiring provided on the printed circuit board.

4. The power transmission device according to claim 1, wherein a portion of the rotating member protrudes from the first opening of the magnetic core in the first direction in a plane intersecting the axial direction.

5. The power transmission device according to claim 4, wherein a portion of the first winding provided on the rotating member protrudes from the first opening of the magnetic core in the first direction in a plane intersecting the axial direction.

6. A motor device comprising: a motor having a motor stator including a first motor magnetic core and a first motor winding, and a motor rotor including a second motor magnetic core and a second motor winding; a shaft connected to the motor rotor; an inverter; a rotating member connected to the shaft and rotatable in the circumferential direction of the shaft; a first winding provided on the rotating member and wound along the circumferential direction; a second winding provided in an axial direction of the shaft at a position different from the position at which the rotating member is provided, wound along the circumferential direction, and connected to the inverter; a magnetic core provided so as to surround the rotating member and the second winding, and having a first opening provided on a surface facing away from the shaft in a first direction intersecting the axial direction; and a rectifier circuit provided in a path connecting the first winding and the second motor winding.

7. The motor device according to claim 6, further comprising a cooling device capable of supplying a cooling medium toward the first opening of the magnetic core.

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