Power transmission device and motor apparatus

Abstract

A power transmission device according to one embodiment of the present invention is provided with a magnetic core, a first winding, a rotating member, a second winding, and a first magnetic body. The magnetic core has an annular shape including a through hole through which the shaft passes, includes a cavity therein along the circumferential direction of the rotation axis of the shaft, and has a first opening provided on a first surface in contact with the through hole along the circumferential direction, the first opening connecting the through hole and the cavity. The first winding is disposed in the cavity and wound in a circumferential direction. The rotating member is provided at a position corresponding to the first opening in the axial direction of the rotating shaft, and is rotatable in the circumferential direction inside the cavity in response to rotation of the shaft. The second winding is provided on the rotating member and wound in a circumferential direction. The first magnetic body is provided in a portion of the rotating member corresponding to the first opening of the magnetic core in the circumferential direction.

Description

Technical Field

[0001] The present invention relates to a power transmission device for contactlessly transmitting electric power and a motor device provided with such a power transmission device. Background Art

[0002] For example, the electric motor can be an electrically excited synchronous motor (EESM). This type of motor has a stator with windings and a rotor with windings. In such a motor, the efficiency of the motor can be improved by varying the current flowing through the windings wound around the rotor according to the motor's rotational speed.

[0003] However, there are devices that can transmit power between a stator and a rotor. For example, Patent Document 1 discloses a rotary transformer that includes a stator with a winding wound thereon and a rotor with a winding wound thereon, and that can transmit power between the stator and the rotor. [Prior art literature] [Patent Document]

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-75760 Summary of the Invention

[0005] In electric motor devices, high motor efficiency is desired, and further improvement of the motor efficiency is also desired.

[0006] It is desirable to provide a power transmission device and a motor apparatus capable of improving the efficiency of a motor.

[0007] An embodiment of the present invention relates to a power transmission device comprising a magnetic core, a first winding, a rotating member, a second winding, and a first magnetic body. The magnetic core is annular and includes a through hole for a shaft to pass through. The core includes a cavity in the interior thereof along the circumferential direction of the rotation axis of the shaft, and has a first opening portion, the first opening portion being circumferentially arranged on a first surface connected to the through hole, the first opening portion connecting the through hole and the cavity. The first winding is arranged in the cavity and wound circumferentially. The rotating member is arranged at a position corresponding to the first opening portion in the axial direction of the rotating shaft and can rotate circumferentially inside the cavity in response to the rotation of the shaft. The second winding is arranged on the rotating member and wound circumferentially. The first magnetic body is circumferentially arranged on a portion of the rotating member corresponding to the first opening portion of the magnetic core.

[0008] Another embodiment of the present invention includes a motor device comprising a motor, a shaft, an inverter, a magnetic core, a first winding, a rotating member, a second winding, a first magnetic body, and a rectifier circuit. The motor comprises a motor stator and a motor rotor. The motor stator includes a first motor core and a first motor winding, and the motor rotor includes a second motor core and a second motor winding. The shaft is connected to the motor rotor. The magnetic core is annular and includes a through-hole through which the shaft passes. The core includes a cavity circumferentially along the shaft's rotation axis and a first opening. The first opening is circumferentially arranged on a first surface adjacent to the through-hole, connecting the through-hole and the cavity. The first winding is connected to the inverter, disposed in the cavity, and wound circumferentially. The rotating member is disposed at a position corresponding to the first opening in the axial direction of the rotating shaft and can rotate circumferentially within the cavity in response to the rotation of the shaft. The second winding is disposed on the rotating member and wound circumferentially. The first magnetic body is circumferentially arranged on a portion of the rotating member corresponding to the first opening of the magnetic core. The rectifier circuit is disposed on a path connecting the second winding and the second motor winding.

[0009] According to the power transmission device and the motor apparatus according to one embodiment of the present invention, the efficiency of the motor can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] [ Figure 1 ] Figure 1 This is a block diagram showing a configuration example of a motor device according to an embodiment of the present invention. [ Figure 2 ] Figure 2 Yes Figure 1 A perspective view of a structural example of a power transmission device shown. [ Figure 3 ] Figure 3 Yes Figure 2 A cross-sectional view of a structural example of a power transmission device shown. [ Figure 4 ] Figure 4 Yes Figure 3 An explanatory diagram of a structural example of a stator shown. [ Figure 5 ] Figure 5 Yes Figure 3 An explanatory diagram of a structural example of a rotor shown. [ Figure 6 ] Figure 6 Yes Figure 3 1 is an explanatory diagram of an operation example of the power transmission device shown. [ Figure 7 ] Figure 7 Yes Figure 3 An explanatory diagram of an example of magnetic flux of a power transmission device shown. [ Figure 8 ] Figure 8 It is an explanatory diagram showing an example of magnetic flux of a power transmission device according to a reference example. [ Figure 9 ] Figure 9 This is an explanatory diagram showing a structural example of a rotor according to a modified example. [ Figure 10 ] Figure 10 This is an explanatory diagram showing a structural example of a rotor according to another modified example. [ Figure 11 ] Figure 11 It is a cross-sectional view showing a structural example of a power transmission device according to another modified example. [ Figure 12 ] Figure 12 It is a perspective view showing a configuration example of a power transmission device according to another modified example. [ Figure 13 ] Figure 13 Yes Figure 12 A cross-sectional view of a structural example of a power transmission device shown. [ Figure 14 ] Figure 14 It is a cross-sectional view showing a structural example of a power transmission device according to another modified example. [ Figure 15 ] Figure 15 Yes Figure 14 An explanatory diagram of a structural example of a rotor shown. [ Figure 16 ] Figure 16 Yes Figure 14 An explanatory diagram of an example of magnetic flux of a power transmission device shown. [ Figure 17 ] Figure 17 It is a cross-sectional view showing a structural example of a power transmission device according to another modified example. [ Figure 18 ] Figure 18 It is a cross-sectional view showing a structural example of a power transmission device according to another modified example. [ Figure 19 ] Figure 19 Yes Figure 18 An explanatory diagram of a structural example of a rotor shown. [ Figure 20 ] Figure 20 It is a cross-sectional view showing a structural example of a power transmission device according to another modified example. [ Figure 21 ] Figure 21 It is a cross-sectional view showing a structural example of a power transmission device according to another modified example. [ Figure 22 ] Figure 22 Yes Figure 21 An explanatory diagram of a structural example of a rotor shown. [ Figure 23 ] Figure 23 Yes Figure 21 1 is an explanatory diagram of an operation example of the power transmission device shown. [ Figure 24 ] Figure 24 It is a cross-sectional view showing a structural example of a power transmission device according to another modified example. [ Figure 25 ] Figure 25 Yes Figure 24 An explanatory diagram of a structural example of a rotor shown. [ Figure 26 ] Figure 26 It is a cross-sectional view showing a structural example of a power transmission device according to another modified example. DETAILED DESCRIPTION

[0011] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0012] <Implementation Method> [Structure example] Figure 1 This figure shows an example configuration of a motor device 1 equipped with a power transmission device according to one embodiment of the present invention. The motor device 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 device 1 on a rotational speed. The DC power supply 9 is configured to supply DC power to the motor device 1. The motor device 1 uses the DC power supplied by the DC power supply 9 to generate mechanical energy, or driving force, in accordance with instructions from the external control device 8. The motor device 1 includes a drive unit 10 and a motor 30.

[0013] The drive unit 10 is configured to drive the electric motor 30 . The drive unit 10 includes inverters 11 and 12 , a power transmission device 20 , a rectifier circuit 14 , and a control circuit 19 .

[0014] The inverter 11 is configured to convert the DC power supplied by the DC power supply 9 into three-phase (U-phase, V-phase, and W-phase) AC power in accordance with instructions from the control circuit 19. Furthermore, the inverter 11 supplies this three-phase AC power to the windings 31B (described later) of the stator 31 of the motor 30.

[0015] Inverter 12 is configured to convert DC power supplied from DC power source 9 into single-phase AC power according to instructions from control circuit 19. Inverter 12 also supplies this AC power to winding 21B of stator 21 of power transmission device 20 (described later).

[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 21 , a rotor 22 , and a shaft 24 .

[0017] Figure 2 One configuration example of the power transmission device 20 is shown. Figure 3 An example of a cross-sectional structure of the power transmission device 20 in a plane including the rotation axis AZ is shown. Figure 4 : shows a structural example of the stator 21. Figure 4 , a cross-sectional structure of the stator 21 in a plane including the rotation axis AZ in the direction of arrows IV-IV is also depicted. Figure 5 1 shows an example of the structure of the rotor 22. Figure 5 , a cross-sectional structure of the rotor 22 in a plane including the rotation axis AZ in the VV arrow direction is also depicted.

[0018] The stator 21 is a so-called stator, and is fixed to a housing (not shown) of the motor device 1. Figure 2 , as shown in 3, it has a magnetic core 21A and a winding 21B.

[0019] The magnetic core 21A is made of a magnetic material such as ferrite. The magnetic cores 21A1 and 21A2 are arranged in the Z direction so as to sandwich the rotor 22 and be spaced a predetermined distance apart. Here, the Z direction is the extension direction of the rotation axis AZ, which is the direction from the motor 30 toward the power transmission device 20. The magnetic core 21A has a magnetic core 21A1 and a magnetic core 21A2. The magnetic core 21A1 is an annular magnetic component having a through hole 120 for the shaft 24 to pass through, and has a flat plate shape in this example. The magnetic core 21A2 is an annular magnetic component having a through hole 120 for the shaft 24 to pass through. In the magnetic core 21A2, on the surface S21 ( Figure 3 ,4), along the circumferential direction A( Figure 4 ), a groove-shaped recess 121 is provided. With this structure, a cavity 122 is provided along the circumferential direction A in the core 21A having the core 21A1 and the core 21A2, and an opening 123 and an opening 124 are provided. The opening 123 connects the radial direction ( Figure 3 The opening 124 connects the space inside the core 21A in the lateral direction (in the horizontal direction) and the cavity 122, and the space outside the core 21A in the radial direction and the cavity 122.

[0020] The winding 21B is wound multiple times along the recessed portion 121 of the core 21A2. The winding 21B is connected to the inverter 12 through, for example, a hole (not shown) provided in the core 21A2.

[0021] The rotor 22 is a so-called rotor, and is configured to rotate around the rotation axis AZ. The rotor 22 is arranged in the Z direction so as to be sandwiched between the magnetic core 21A1 and the magnetic core 21A2 of the stator 21, and is fixed to the shaft 24. Figure 3 ,5, having a substrate 22A, a winding 22B, a magnetic body 22C and a magnetic body 22E.

[0022] The substrate 22A is, for example, a printed circuit board (PCB). The substrate 22A is connected to the shaft 24 and rotates in the circumferential direction A around the rotation axis AZ in response to the rotation of the shaft 24 .

[0023] The winding 22B is formed by pattern wiring provided on the substrate 22A, and is arranged along the circumferential direction A ( Figure 5 ) is wound multiple times. The winding 22B is made of a metal material such as copper. In this example, the winding 22B is provided on both sides of the substrate 22A. Furthermore, the present invention is not limited thereto, and the winding 22B may be provided on one of the two sides of the substrate 22A. In addition, when the substrate 22A is a multi-layer substrate, the winding 22B may be formed using pattern wiring inside the substrate 22A. One end and the other end of the winding 22B are connected to the rectifier circuit 14 through a portion 22D (described later) of the substrate 22A and wiring (not shown) provided on the shaft 24.

[0024] The magnetic body 22C is made of a magnetic material such as ferrite. Figure 3 As shown, it is set at a position of the rotor 22 corresponding to the opening portion 123 of the stator 21. Figure 5 As shown, the magnetic body 22C is provided in a manner extending in the circumferential direction A along the rotation axis AZ. In this example, the magnetic body 22C has the shape of the letter "C". Specifically, a cutout portion in the shape of the letter "C" is provided in the substrate 22A, and the magnetic body 22C is embedded in the cutout portion of the substrate 22A. The portion of the substrate 22A located on the inner side of the magnetic body 22C and the portion located on the outer side of the magnetic body 22C are connected through the portion 22D of the substrate 22A. Furthermore, the present invention is not limited thereto, and the magnetic body 22C may also be annular. In this case, for example, an insulating film may be provided on the surface of a portion of the magnetic body 22C, and wiring connecting one end and the other end of the winding 22B to the rectifier circuit 14 may be provided on the insulating film. In this example, the radial direction ( Figure 3 The width (in the horizontal direction) is the same as the width of the convex portion near the opening portion 123 of the two convex portions on both sides of the radial recess 121 of the magnetic core 21A2.

[0025] The magnetic body 22E is made of a magnetic material such as ferrite. Figure 3 As shown, it is provided at a position of the rotor 22 corresponding to the opening 124 of the stator 21. Figure 5 As shown in FIG. 1 , the magnetic body 22E is provided in a manner extending along the circumferential direction A centered on the rotation axis AZ. In this example, the magnetic body 22E has a ring shape. Specifically, a ring-shaped cutout portion is provided in the substrate 22A, and the magnetic body 22E is embedded in the cutout portion of the substrate 22A. In this example, the radial direction ( Figure 3 The width (in the horizontal direction) is the same as the width of the convex portion near the opening portion 124 of the two convex portions on both sides of the radial recess 121 of the magnetic core 21A2.

[0026] In the power transmission device 20, as Figure 3 As shown, near opening 123, a gap G is provided between magnetic core 21A1 and magnetic body 22C, and a gap G is provided between magnetic body 22C and the protrusion of magnetic core 21A2 near opening 123. Thus, in power transmission device 20, near opening 123, magnetic core 21A1 and magnetic core 21A2 are magnetically coupled to each other via magnetic body 22C. Similarly, near opening 124, a gap G is provided between magnetic core 21A1 and magnetic body 22E, and a gap G is provided between magnetic body 22E and the protrusion of magnetic core 21A2 near opening 124. Thus, in power transmission device 20, near opening 124, magnetic core 21A1 and magnetic core 21A2 are magnetically coupled to each other via magnetic body 22E. With this configuration, power transmission device 20 converts the AC power supplied from inverter 12 at a ratio of the number of turns of winding 21B to the number of turns of winding 22B, and supplies the converted AC power to rectifier circuit 14. Power transmission device 20 is also called a rotary transformer.

[0027] The shaft 24 is connected to the rotor 32 of the motor 30 and is configured to rotate about the rotation axis AZ in response to the driving force generated by the motor 30 .

[0028] Rectification circuit 14 ( Figure 1 ) is configured to rectify the AC power supplied from the winding 22B of the rotor 22 and supply the rectified power to the winding 32B of the rotor 32 of the motor 30 (described later). The rectifier circuit 14 is connected to the shaft 24, which is not shown. That is, because the winding 22B and the rotor 32 of the motor 30 are connected to the shaft 24, the rectifier circuit 14 is also connected to the shaft 24. In this example, although the power rectified by the rectifier circuit 14 is directly supplied to the winding 32B, this is not limited to this. As an alternative, for example, the power rectified by the rectifier circuit 14 may be supplied to the winding 32B through a stabilization circuit including a capacitor.

[0029] 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 30. Specifically, the control circuit 19 controls the rotational speed of the motor 30 by controlling 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 30. Furthermore, the control circuit 19 controls the intensity of the magnetic field generated by the rotor 32 of the motor 30 by controlling the operation of the inverter 12 based on the control signal indicating the rotational speed supplied from the motor 30. Specifically, the control circuit 19 strengthens the magnetic field generated by the rotor 32 of the motor 30 when the rotational speed of the motor 30 is slow, and weakens the magnetic field generated by the rotor 32 of the motor 30 when the rotational speed of the motor 30 is fast.

[0030] The motor 30 is an electrically excited synchronous motor and includes a stator 31 , a rotor 32 , and a sensor 33 .

[0031] Stator 31 is a so-called stator and is fixed to a housing (not shown) of motor 30. Stator 31 includes core 31A and winding 31B. Winding 31B is supplied with three-phase (U-phase, V-phase, W-phase) AC power generated by inverter 11.

[0032] The rotor 32 is a so-called rotor and is configured to rotate about the rotation axis AZ. The rotor 32 includes a core 32A and a winding 32B. A signal rectified by the rectifier circuit 14 is supplied to the winding 32B.

[0033] The sensor 33 is configured to detect the rotation speed of the rotor 32. The sensor 33 also supplies a control signal indicating the rotation speed of the rotor 32 to the control circuit 19.

[0034] With this configuration, in motor device 1, the rotational speed of motor 30 is controlled based on the three-phase (U-phase, V-phase, and W-phase) AC power generated by inverter 11, and the magnetic field generated by rotor 32 of motor 30 is controlled based on the single-phase AC power generated by inverter 12. In motor device 1, for example, when the rotational speed of motor 30 is slow, the magnetic field generated by rotor 32 of motor 30 is strengthened; when the rotational speed of motor 30 is fast, the magnetic field generated by rotor 32 of motor 30 is weakened. Consequently, in motor device 1, the efficiency of motor 30 can be improved over a wide rotational speed range.

[0035] Here, shaft 24 corresponds to a specific example of an "axis" in one embodiment of the present disclosure. Rotation axis AZ corresponds to a specific example of a "rotation axis" in one embodiment of the present disclosure. Magnetic core 21A corresponds to a specific example of a "magnetic core" in one embodiment of the present disclosure. Hollow 122 corresponds to a specific example of a "hollow" in one embodiment of the present disclosure. Opening 123 corresponds to a specific example of a "first opening" in one embodiment of the present disclosure. Winding 21B corresponds to a specific example of a "first winding" in one embodiment of the present disclosure. Substrate 22A corresponds to a specific example of a "rotating member" in one embodiment of the present disclosure. Winding 22B corresponds to a specific example of a "second winding" in one embodiment of the present disclosure. Magnetic body 22C corresponds to a specific example of a "first magnetic body" in one embodiment of the present disclosure. Opening 124 corresponds to a specific example of a "second opening" in one embodiment of the present disclosure. Magnetic body 22E corresponds to a specific example of a "second magnetic body" in one embodiment of the present disclosure.

[0036] The stator 31 corresponds to a specific example of a "motor stator" in one embodiment of the present disclosure. The magnetic core 31A corresponds to a specific example of a "first motor magnetic core" in one embodiment of the present disclosure. The winding 31B corresponds to a specific example of a "first motor winding" in one embodiment of the present disclosure. The rotor 32 corresponds to a specific example of a "motor rotor" in one embodiment of the present disclosure. The magnetic core 32A corresponds to a specific example of a "second motor magnetic core" in one embodiment of the present disclosure. The winding 32B corresponds to a specific example of a "second motor winding" in one embodiment of the present disclosure. The inverter 12 corresponds to a specific example of an "inverter" in one embodiment of the present disclosure. The rectifier circuit 14 corresponds to a specific example of a "rectifier circuit" in one embodiment of the present disclosure.

[0037] [Action and Effect] Next, the operation and effect of the motor device 1 according to the present embodiment will be described.

[0038] (Overall action summary) 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 30. In response to instructions from the control circuit 19, the inverter 11 converts the DC power supplied by the DC power supply 9 into three-phase (U-phase, V-phase, and W-phase) AC power and supplies this three-phase AC power to the winding 31B of the stator 31 of the motor 30. In response to instructions from the control circuit 19, the inverter 12 converts the DC power supplied by the DC power supply 9 into single-phase AC power and supplies this AC power to the winding 21B of the stator 21 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 by the winding 22B of the rotor 22 and supplies the rectified power to the winding 32B of the rotor 32 of the motor 30. Motor 30 generates mechanical energy, or driving force, from three-phase (U-phase, V-phase, and W-phase) AC power supplied from inverter 11. This causes shaft 24 to rotate about rotation axis AZ. A sensor 33 of motor 30 provides a control signal indicating the rotational speed of motor 30 to control circuit 19.

[0039] [Action and Effect] Next, the operation and effect of the power transmission device 20 according to this embodiment will be described.

[0040] AC power is supplied from the inverter 12 to the winding 21B of the stator 21 of the power transmission device 20. The rotor 22 rotates about the rotation axis AZ, for example, along Figure 2 The circumferential direction A of rotation is shown.

[0041] Figure 6 A cross-sectional view of stator 21 and rotor 22 of power transmission device 20 is shown. Winding 21B of stator 21 generates a magnetic field based on the AC power supplied from inverter 12. Near opening 123, the protrusions of magnetic core 21A1 and magnetic core 21A2 near opening 123 are magnetically coupled to each other via magnetic body 22C. Furthermore, near opening 124, the protrusions of magnetic core 21A1 and magnetic core 21A2 near opening 124 are magnetically coupled to each other via magnetic body 22E.

[0042] Figure 7 An example of the magnetic flux of the openings 123 and 124 of the power transmission device 20 is shown. Figure 7In the figure, a portion of the power transmission device 20 is omitted. Leakage magnetic flux is generated near openings 123 and 124. The direction of this leakage magnetic flux changes according to the polarity of the AC power. Near opening 123, in this example, leakage magnetic flux is generated from magnetic core 21A2 toward magnetic body 22C, and leakage magnetic flux is generated from magnetic body 22C toward magnetic core 21A1. Thus, near opening 123, magnetic core 21A1 and magnetic core 21A2 are magnetically coupled to each other via magnetic body 22C. Furthermore, near opening 124, in this example, leakage magnetic flux is generated from magnetic core 21A1 toward magnetic body 22E, and leakage magnetic flux is generated from magnetic body 22E toward magnetic core 21A2. Thus, near opening 124, magnetic core 21A1 and magnetic core 21A2 are magnetically coupled to each other via magnetic body 22E.

[0043] Thus, in the power transmission device 20, as shown in FIG. Figure 6 As shown, a magnetic path MP is generated through the magnetic core 21A1, the magnetic body 22C, the magnetic core 21A2, and the magnetic body 22E.

[0044] The winding 22B of the rotor 22 generates AC power based on the magnetic field of the magnetic circuit MP and supplies 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 through contactless transmission.

[0045] As described above, in the power transmission device 20 , since power is transmitted by non-contact transmission, reliability can be improved compared to a case where power is transmitted by contact transmission using, for example, a slip ring and a brush.

[0046] Rectifier circuit 14 rectifies the AC power supplied from winding 22B of rotor 22 and supplies the rectified power to winding 32B of rotor 32 of motor 30. This generates a magnetic field in rotor 32 of motor 30. For example, control circuit 19 strengthens the magnetic field generated by rotor 32 of motor 30 when the rotation speed of motor 30 is slow, and weakens the magnetic field generated by rotor 32 of motor 30 when the rotation speed of motor 30 is fast. Consequently, motor device 1 can improve the efficiency of motor 30 over a wide rotation speed range.

[0047] As described above, in power transmission device 20, rotor 22 is formed using substrate 22A provided with windings 22B. This reduces the weight of rotor 22, thereby reducing rotational torque and inertia, compared to, for example, a rotor core as in Patent Document 1.

[0048] Furthermore, the provision of magnetic material 22C in power transmission device 20 suppresses the spread of leakage flux near opening 123, reducing the likelihood of leakage flux entering shaft 24 and winding 22B. Furthermore, the provision of magnetic material 22E suppresses the spread of leakage flux near opening 124, reducing the likelihood of leakage flux entering winding 22B. As a result, power transmission device 20 can reduce energy loss and improve motor efficiency.

[0049] That is to say, if Figure 8 As shown, when the magnetic body 22C is not provided, a gap G is provided between the convex portions near the opening 123 of the magnetic core 21A1 and the magnetic core 21A2, so the gap G becomes longer. Figure 8 As shown, the leakage flux may be in the radial direction ( Figure 8 If the leakage flux enters the shaft 24, eddy currents are generated in the shaft 24, and energy loss occurs. In addition, if the leakage flux enters the winding 22B, eddy currents are generated in the winding 22B, and energy loss occurs. Similarly, when the magnetic body 22E is not provided, since a gap G is provided between the convex portions near the opening 124 of the magnetic core 21A1 and the opening 124 of the magnetic core 21A2, the gap G becomes longer. Therefore, as shown in FIG. Figure 8 As shown, the leakage flux may be in the radial direction ( Figure 8 If the leakage magnetic flux enters the winding 22B, an eddy current is generated in the winding 22B, resulting in energy loss.

[0050] On the other hand, in the power transmission device 20, since the magnetic bodies 22C and 22E are provided, the gap G can be shortened, thereby suppressing the radial direction ( Figure 7 Thus, since the possibility of leakage flux entering the shaft 24 and the winding 22B can be reduced, energy loss can be reduced and the efficiency of the motor can be improved.

[0051] As described above, the power transmission device 20 includes a magnetic core 21A, a first winding (winding 21B), a substrate 22A, a second winding (winding 22B), and a first magnetic body (magnetic body 22C). The magnetic core 21A has a ring-shaped shape, including a through-hole 120 through which the shaft 24 passes. It contains a cavity 122 along the circumferential direction A of the rotation axis AZ of the shaft 24. The core 21A also has a first opening (opening 123) provided on the first surface in contact with the through-hole 120 along the circumferential direction A, connecting the through-hole 120 and the cavity 122. The winding 21B is disposed in the cavity 122 and wound along the circumferential direction A. The substrate 22A is provided at a position corresponding to the first opening (opening 123) in the axial direction of the rotation axis AZ and can rotate within the cavity 122 along the circumferential direction A in response to the rotation of the shaft 24. The winding 22B is disposed on the substrate 22A and wound along the circumferential direction A. Magnetic body 22C is provided along circumferential direction A in a portion of substrate 22A corresponding to opening 123 of magnetic core 21A. This prevents the spread of leakage magnetic flux near opening 123, reducing the likelihood of leakage magnetic flux entering shaft 24 and winding 22B. As a result, power transmission device 20 can reduce energy loss and improve motor efficiency.

[0052] The power transmission device 20 further includes a second magnetic body (magnetic body 22E). The magnetic core 21A has a second opening (opening 124) on a second surface opposite the first surface in the radial direction of the rotation axis AZ. Opening 124 is located at a position corresponding to the first opening (opening 123) in the axial direction. The magnetic body 22E is provided along the circumferential direction A at a portion of the substrate 22A corresponding to the second opening (opening 124) of the magnetic core 21A. This prevents the spread of leakage flux near the opening 124, reducing the likelihood of leakage flux entering the winding 22B. As a result, the power transmission device 20 can reduce energy loss and improve the efficiency of the motor.

[0053] [Effect] As described above, in this embodiment, there are provided a magnetic core, a first winding, a substrate, a second winding, and a first magnetic body. The magnetic core is in a ring shape including a through hole for the shaft to pass through, and contains a cavity in the interior thereof along the circumferential direction of the rotating axis of the shaft, and has a first opening portion, the first opening portion is circumferentially arranged on the first surface connected to the through hole, and the first opening portion connects the through hole and the cavity. The first winding is arranged in the cavity and wound in the circumferential direction. The substrate is arranged at a position corresponding to the first opening portion in the axial direction of the rotating axis, and can rotate in the circumferential direction inside the cavity corresponding to the rotation of the shaft. The second winding is arranged on the substrate and wound in the circumferential direction. The first magnetic body is circumferentially arranged in the portion of the substrate corresponding to the first opening portion of the magnetic core. Therefore, the efficiency of the motor can be improved.

[0054] This embodiment further includes a second magnetic body. The magnetic core has a second opening on a second surface, radially opposite to the first surface, with respect to the rotation axis. The second opening is located at a position corresponding to the first opening in the axial direction. The second magnetic body is circumferentially disposed on the substrate at a portion corresponding to the second opening in the magnetic core. This improves the efficiency of the motor.

[0055] [Variation 1] In the above embodiment, although Figure 5 As shown in FIG, the magnetic body 22C is formed by using one magnetic body, but it is not limited to this. Figure 9 As shown in FIG. 2 , a plurality of magnetic bodies may be used to form the magnetic body 22C. Figure 9 In the example of FIG, two magnetic bodies are used to constitute the magnetic body 22C.

[0056] [Variation 2] In the above embodiment, although Figure 3 ,5, a magnetic body 22E is provided, but it is not limited thereto. As an alternative, as Figure 10 As shown, the magnetic body 22E may not be provided.

[0057] [Variation 3] In the above embodiment, although Figure 3 As shown, the radial direction of the magnetic body 22C ( Figure 3 The width of the core 21A2 in the transverse direction is the same as the width of the convex portion near the opening 123 of the two convex portions on both sides of the radial concave portion 121, but is not limited to this. As an alternative, Figure 11 As shown, the radial direction of the magnetic body 22C ( Figure 11 The width (in the horizontal direction) of the core 21A2 may also be wider than the width of the convex portion near the opening portion 123 of the two convex portions on both sides of the radial recess 121 of the core 21A2.

[0058] Similarly, although the radial direction ( Figure 3 The width of the core 21A2 in the transverse direction is the same as the width of the convex portion near the opening 124 of the two convex portions on both sides of the radial concave portion 121, but is not limited to this. As an alternative, Figure 11 As shown, the radial direction of the magnetic body 22E ( Figure 11 The width (in the horizontal direction) of the core 21A2 may also be wider than the width of the convex portion near the opening portion 124 of the two convex portions on both sides of the radial recess 121 of the core 21A2.

[0059] [Variation 4] In the above embodiment, although Figure 3 As shown, the core 21A has an opening 123 and an opening 124, but the present invention is not limited thereto. Alternatively, as shown in FIG. Figure 12 ,13, it is also possible to have only one opening 123. In this example, as Figure 13 As shown, the radial direction of the magnetic core 21A1 ( Figure 13 The outer portion (laterally) of the rotor 21A1 is bent in the Z direction and connected to the magnetic core 21A2 at the connection portion 125. During the manufacturing process of the power transmission device 20, the magnetic core 21A1, rotor 22, and magnetic core 21A2 are arranged in sequence in the Z direction, with the magnetic core 21A1, rotor 22, and magnetic core 21A2 positioned close to each other. The magnetic core 21A1 and magnetic core 21A2 are then bonded together at the connection portion 125, for example. Since the power transmission device 20 does not have the opening 124, there is no leakage flux through the opening 124, which reduces energy loss and improves motor efficiency.

[0060] [Variation 5] In the above embodiment, although Figure 5 As shown, the magnetic bodies 22C and 22E are embedded in the cutout portion of the substrate 22A, but the present invention is not limited thereto. As an alternative, as shown in FIG. Figure 14 , 15, the magnetic bodies 22C and 22E may be provided on the surface of the substrate 22A. In this example, the rotor 22 has the magnetic body 22C (magnetic body 22C1, 22C2) and the magnetic body 22E (magnetic body 22E1, 22E2). Figure 14 As shown, magnetic body 22C1 is provided on the surface of substrate 22A on the side where magnetic core 21A1 is provided, and magnetic body 22C2 is provided on the surface of substrate 22A on the side where magnetic core 21A2 is provided. In this example, magnetic body 22C1 and magnetic body 22C2 have a ring shape. One end and the other end of winding 22B are connected to rectifier circuit 14, for example, at portion 22D1, via pattern wiring within substrate 22A. Magnetic body 22E1 is provided on the surface of substrate 22A on the side where magnetic core 21A1 is provided, and magnetic body 22E2 is provided on the surface of substrate 22A on the side where magnetic core 21A2 is provided.

[0061] Figure 16An example of magnetic flux through openings 123 and 124 of power transmission device 20 according to this modified example is shown. Near opening 123, in this example, magnetic flux leakage occurs from magnetic core 21A2 toward magnetic body 22C2, magnetic flux leakage occurs from magnetic body 22C2 toward magnetic body 22C1, and magnetic flux leakage occurs from magnetic body 22C1 toward magnetic core 21A1. Thus, near opening 123, magnetic cores 21A1 and 21A2 are magnetically coupled to each other via magnetic bodies 22C1 and 22C2. Furthermore, near opening 124, in this example, magnetic flux leakage occurs from magnetic core 21A1 toward magnetic body 22E1, magnetic flux leakage occurs from magnetic body 22E1 toward magnetic body 22E2, and magnetic flux leakage occurs from magnetic body 22E2 toward magnetic core 21A2. In this manner, near the opening 124 , the magnetic core 21A1 and the magnetic core 21A2 are magnetically coupled to each other via the magnetic bodies 22E1 and 22E2 .

[0062] In the power transmission device 20 of this modification, since the magnetic body 22C (magnetic bodies 22C1, 22C2) and the magnetic body 22E (magnetic bodies 22E1, 22E2) are provided, the power transmission device 20 of this modification is different from the case of the above embodiment ( Figure 7 ) can be shortened, thereby further suppressing the radial direction ( Figure 16 Thus, since the possibility of leakage flux entering the shaft 24 and the winding 22B can be further reduced, energy loss can be reduced and the efficiency of the motor can be improved.

[0063] Furthermore, in this example, although the radial direction ( Figure 14 The width of the core 21A2 in the transverse direction is the same as the width of the convex portion near the opening 123 of the two convex portions on both sides of the radial concave portion 121, but is not limited to this. As an alternative, Figure 17 As shown, the radial direction of the magnetic bodies 22C1, 22C2 ( Figure 17 The width (in the horizontal direction) of the core 21A2 may also be wider than the width of the convex portion near the opening portion 123 of the two convex portions on both sides of the radial recess 121 of the core 21A2.

[0064] Similarly, although the radial direction ( Figure 14 The width of the core 21A2 in the transverse direction is the same as the width of the convex portion near the opening 124 of the two convex portions on both sides of the radial concave portion 121, but is not limited to this. As an alternative, Figure 17 As shown, the radial direction of the magnetic bodies 22E1, 22E2 ( Figure 17 The width (in the horizontal direction) of the core 21A2 may also be wider than the width of the convex portion near the opening portion 124 of the two convex portions on both sides of the radial recess 121 of the core 21A2.

[0065] [Variation 6] In the above embodiment, although Figure 5 As shown, the magnetic bodies 22C and 22E are embedded in the cutout portion of the substrate 22A, but the present invention is not limited thereto. As an alternative, as shown in FIG. Figure 18 As shown in FIG19 , magnetic bodies 22C and 22E may also be embedded within substrate 22A. In this example, magnetic bodies 22C and 22E have an annular shape. Magnetic body 22C is disposed within substrate 22A in a portion corresponding to opening 123. One end and the other end of winding 22B are connected to rectifier circuit 14, for example, at portion 22D2, via patterned wiring on the surface of substrate 22A in which magnetic body 22C is embedded. Magnetic body 22E is disposed within substrate 22A in a portion corresponding to opening 124.

[0066] Furthermore, in this example, although the radial direction ( Figure 18 The width of the core 21A2 in the transverse direction is the same as the width of the convex portion near the opening 123 of the two convex portions on both sides of the radial concave portion 121, but is not limited to this. As an alternative, Figure 20 As shown, the radial direction of the magnetic body 22C ( Figure 20 The width (in the horizontal direction) of the core 21A2 may also be wider than the width of the convex portion near the opening portion 123 of the two convex portions on both sides of the radial recess 121 of the core 21A2.

[0067] Similarly, although the radial direction ( Figure 18 The width of the core 21A2 in the transverse direction is the same as the width of the convex portion near the opening 124 of the two convex portions on both sides of the radial concave portion 121, but is not limited to this. As an alternative, Figure 20 As shown, the radial direction of the magnetic body 22E ( Figure 20 The width (in the horizontal direction) of the core 21A2 may also be wider than the width of the convex portion near the opening portion 124 of the two convex portions on both sides of the radial recess 121 of the core 21A2.

[0068] [Variation 7] In the above embodiment, although Figure 3 As shown, the magnetic body 22C is provided only at the position corresponding to the opening 123, but it is not limited thereto. As an alternative, Figure 21 As shown in FIG. 22, a magnetic body 22C may be provided inside the substrate 22A in an area consisting of a portion corresponding to the opening 123 of the magnetic core 21A and a portion outside the opening 123 in the XY plane. In this example, this modification is applied to the power transmission device 20 ( Figure 12,13). The magnetic body 22C is embedded in the substrate 22A. In the power transmission device 20, a gap G is provided between the magnetic core 21A1 and the magnetic body 22C near the opening 123, and a gap G is provided between the magnetic body 22C and the convex portion near the opening 123 of the magnetic core 21A2. In addition, in the radial direction ( Figure 21 A gap G is provided between the outer end portion of the magnetic body 22C (in the horizontal direction) and the magnetic core 21A2.

[0069] Figure 23 A cross-sectional view of the stator 21 and rotor 22 of the power transmission device 20 of this modification is shown. The winding 21B of the stator 21 generates a magnetic field based on the AC power supplied from the inverter 12. Near the opening 123, the magnetic core 21A1 and the magnetic body 22C are magnetically coupled to each other, and the magnetic body 22C and the protrusion near the opening 123 of the magnetic core 21A2 are magnetically coupled to each other. In addition, the radial direction ( Figure 23 The outer end of the magnetic body 22C (in the transverse direction) and the magnetic core 21A2 are magnetically coupled to each other. Figure 6 As shown, a magnetic path MP is generated through core 21A1, magnetic body 22C, and core 21A2, and a magnetic path MP is generated through magnetic body 22C and core 21A2. This reduces the possibility of leakage flux near opening 123 entering shaft 24 and winding 22B, thereby reducing energy loss and improving motor efficiency.

[0070] [Variation 8] In the above embodiment, the rotor 22 is configured using the substrate 22A, but the present invention is not limited thereto, and the rotor 22 may be configured using various members capable of supporting the winding 22B. This modification will be described in detail below.

[0071] Figure 24 ,25 shows a structural example of the power transmission device 20 of this modification. In this example, this modification is applied to the power transmission device 20 of modification 4 ( Figure 12 ,13). The power transmission device 20 includes a rotor 42. The rotor 42 includes a support member 42A, a winding 42B, and a magnetic body 42C.

[0072] The support member 42A is made of resin in this example. The support member 42A is connected to the shaft 24 and rotates around the rotation axis AZ in response to the rotation of the shaft 24. Figure 25 ), a groove-shaped recess 142 is provided.

[0073] Winding 42B is wound multiple times along recess 142 of support member 42A. One end and the other end of winding 42B are connected to rectifier circuit 14 via portion 42D (described later) of support member 42A and wiring (not shown) provided on shaft 24.

[0074] Magnetic body 42C such as Figure 24 As shown, it is set at a position of the rotor 42 corresponding to the opening portion 123 of the stator 21. Figure 25 As shown, the magnetic body 42C is arranged in a manner extending in the circumferential direction A along the rotation axis AZ. In this example, the magnetic body 42C has the shape of the letter "C". Specifically, a cutout portion in the shape of the letter "C" is provided in the support member 42A, and the magnetic body 42C is embedded in the cutout portion of the support member 42A. The portion of the support member 42A located inside the magnetic body 42C and the portion located outside the magnetic body 42C are connected by a portion 42D of the support member 42A. Furthermore, the present invention is not limited thereto, and the magnetic body 42C may also be annular. In this case, for example, an insulating film can be provided on the surface of a portion of the magnetic body 42C, and wiring connecting one end and the other end of the winding 42B to the rectifier circuit 14 can be provided on the insulating film.

[0075] Here, the support member 42A corresponds to a specific example of a "rotating member" in one embodiment of the present disclosure. The winding 42B corresponds to a specific example of a "second winding" in one embodiment of the present disclosure. The magnetic body 42C corresponds to a specific example of a "first magnetic body" in one embodiment of the present disclosure.

[0076] [Variation 9] In the above embodiment, although Figure 3 ,4, along the concave portion 121 of the core 21A2, the winding 21B is directly wound on the core 21A2, but this is not limited to this. As an alternative, as Figure 26 As shown, the bobbin 21C around which the winding 21B is wound may be arranged in the recess 121 of the core 21A2. The bobbin 21C is made of resin, for example.

[0077] [Other modifications] Furthermore, two or more of these modified examples may be combined.

[0078] While the present invention has been described above by way of examples of embodiments and modifications, the present invention is not limited to these embodiments and the like, and various modifications are possible.

[0079] For example, the shapes of the stator 21 and the rotors 22 and 42 shown in the above-mentioned embodiments are merely examples and are not limited to the disclosed shapes.

[0080] 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, the present disclosure can also achieve other effects.

[0081] Furthermore, the present disclosure may have the following aspects. (1) A power transmission device comprising: The magnetic core is annular and includes a through hole for the shaft to pass through, and includes a hollow space therein along the circumferential direction of the rotation axis of the shaft, and has a first opening portion, the first opening portion being provided along the circumferential direction on a first surface connected to the through hole, the first opening portion connecting the through hole and the hollow space; a first winding, disposed in the cavity and wound along the circumferential direction; a rotating member disposed at a position corresponding to the first opening in the axial direction of the rotating shaft and capable of rotating along the circumferential direction within the cavity in response to the rotation of the shaft; a second winding provided on the rotating member and wound along the circumferential direction; and The first magnetic body is provided along the circumferential direction at a portion of the rotating member corresponding to the first opening of the magnetic core. (2) The power transmission device described in (1), wherein The rotating member has a cutout portion extending in the circumferential direction at a portion corresponding to the first opening of the magnetic core. The first magnetic body is provided in the cutout portion of the rotating member. (3) The power transmission device described in (1), wherein The first magnetic body is provided on a surface of a portion of the rotating member corresponding to the first opening of the magnetic core. (4) The power transmission device described in (1), wherein The first magnetic body is provided in a portion of the rotating member corresponding to the first opening of the magnetic core. (5) The power transmission device described in (1), wherein The first magnetic body is provided in a region within the rotating member and within a plane intersecting the rotating axis, and the region includes a portion corresponding to the first opening of the magnetic core and a portion where the second winding is provided. (6) The power transmission device according to any one of (1) to (4), wherein: further comprising a second magnetic body, The magnetic core has a second opening on a second surface opposite to the first surface in the radial direction of the rotating shaft, and the second opening is provided at a position corresponding to the first opening in the axial direction. The second magnetic body is provided along the circumferential direction at a portion of the rotating member corresponding to the second opening of the magnetic core. (7) An electric motor device comprising: an electric motor having a motor stator and a motor rotor, the motor stator including a first motor core and a first motor winding, the motor rotor including a second motor core and a second motor winding; a shaft connected to the motor rotor; Inverter; a magnetic core having a ring shape including a through hole for the shaft to pass through, a hollow cavity inside the core along the circumference of the shaft, and a first opening portion provided on a first surface connected to the through hole along the circumference, the first opening portion connecting the through hole and the hollow cavity; a first winding connected to the inverter, disposed in the cavity, and wound along the circumferential direction; a rotating member disposed at a position corresponding to the first opening in the axial direction of the shaft and capable of rotating in the circumferential direction within the cavity in response to the rotation of the shaft; a second winding, provided on the rotating member and wound along the circumferential direction; a first magnetic body provided along the circumferential direction at a portion of the rotating member corresponding to the first opening of the magnetic core; and The rectifier circuit is provided on a path connecting the second winding and the second motor winding.

Claims

1. A power transmission device comprising: The magnetic core is annular and includes a through hole for the shaft to pass through, and includes a hollow space therein along the circumferential direction of the rotation axis of the shaft, and has a first opening portion, the first opening portion being provided along the circumferential direction on a first surface connected to the through hole, the first opening portion connecting the through hole and the hollow space; a first winding, disposed in the cavity and wound along the circumferential direction; a rotating member disposed at a position corresponding to the first opening in the axial direction of the rotating shaft and capable of rotating along the circumferential direction within the cavity in response to the rotation of the shaft; a second winding, provided on the rotating member and wound along the circumferential direction; as well as The first magnetic body is provided along the circumferential direction at a portion of the rotating member corresponding to the first opening of the magnetic core.

2. The power transmission device according to claim 1, wherein The rotating member has a cutout portion extending in the circumferential direction at a portion corresponding to the first opening of the magnetic core. The first magnetic body is provided in the cutout portion of the rotating member.

3. The power transmission device according to claim 1, wherein The first magnetic body is provided on a surface of a portion of the rotating member corresponding to the first opening of the magnetic core.

4. The power transmission device according to claim 1, wherein The first magnetic body is provided in a portion of the rotating member corresponding to the first opening of the magnetic core.

5. The power transmission device according to claim 1, wherein The first magnetic body is provided in a region within the rotating member and within a plane intersecting the rotating axis, and the region includes a portion corresponding to the first opening of the magnetic core and a portion where the second winding is provided. The power transmission device according to claim 1 , wherein: further comprising a second magnetic body, The magnetic core has a second opening on a second surface opposite to the first surface in the radial direction of the rotating shaft, and the second opening is provided at a position corresponding to the first opening in the axial direction. The second magnetic body is provided along the circumferential direction at a portion of the rotating member corresponding to the second opening of the magnetic core.

7. An electric motor device comprising: an electric motor having a motor stator and a motor rotor, the motor stator including a first motor core and a first motor winding, the motor rotor including a second motor core and a second motor winding; a shaft connected to the motor rotor; Inverter; a magnetic core having a ring shape including a through hole for the shaft to pass through, a hollow cavity inside the core along the circumference of the shaft, and a first opening portion provided on a first surface connected to the through hole along the circumference, the first opening portion connecting the through hole and the hollow cavity; a first winding connected to the inverter, disposed in the cavity, and wound along the circumferential direction; a rotating member disposed at a position corresponding to the first opening in the axial direction of the shaft and capable of rotating in the circumferential direction within the cavity in response to the rotation of the shaft; a second winding, provided on the rotating member and wound along the circumferential direction; a first magnetic body provided along the circumferential direction at a portion of the rotating member corresponding to the first opening of the magnetic core; as well as The rectifier circuit is provided on a path connecting the second winding and the second motor winding.

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