Electric power transmission device and motor apparatus
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-02-05
- Publication Date
- 2026-08-13
Smart Images
Figure JP2025003763_13082026_PF_FP_ABST
Abstract
Description
Power Transmission Device and Motor Device
[0001] The present invention relates to a power transmission device that transmits power non - contact, and a motor device provided with such a power transmission device.
[0002] For example, there is a wound - field synchronous motor (EESM: Electrically Excited Synchronous Motor) for a motor. This motor has a stator wound with windings and a rotor wound with windings. In this motor, the efficiency of the motor can be improved by changing the current flowing through the windings wound around the rotor according to the rotational speed of the motor.
[0003] By the way, there is a device capable of transmitting power between a stator and a rotor. For example, Patent Document 1 discloses a power transmission device capable of supplying power non - contact from a stator to a rotor.
[0004] U.S. Patent No. 5,637,973
[0005] In such a power transmission device, for example, the amount of heat generation can increase as the amount of power transmitted increases. Therefore, it is expected that the power transmission device is easy to dissipate heat.
[0006] It is desirable to provide a power transmission device and a motor device that can be easily cooled.
[0007] A power transmission device according to one embodiment of the present invention comprises a shaft, a stator, a rotor, a heat sink, and one or more rectifier elements. The shaft is rotatable about a rotation axis. The stator is provided spaced apart from the shaft and has a first winding wound in the circumferential direction of the shaft. The rotor is connected to the shaft, is rotatable in the circumferential direction of the shaft, and has a second winding wound in the circumferential direction of the shaft. The heat sink is connected to the shaft at a position in the axial direction of the shaft different from the position where the rotor is provided, is rotatable in the circumferential direction of the shaft, and has a plurality of vanes provided on the outer circumference away from the shaft on a first surface intersecting the rotation axis. One or more rectifier elements are provided on the first surface of the heat sink in the portion surrounded by the plurality of vanes, are thermally connected to the heat sink via the first surface, and are connected to the second winding. The plurality of vanes allow air to flow in the portion surrounded by the plurality of vanes as the heat sink rotates in the circumferential direction.
[0008] A motor device according to one embodiment of the present invention comprises a motor, a shaft, a stator, a rotor, a heat sink, and one or more rectifier elements. The motor has 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 and is rotatable about a rotation axis. The stator is provided spaced apart from the shaft and has a first winding wound in the circumferential direction of the shaft. The rotor is connected to the shaft, is rotatable in the circumferential direction of the shaft, and has a second winding wound in the circumferential direction of the shaft. The heat sink is connected to the shaft at a position in the axial direction of the shaft different from the position where the rotor is provided, is rotatable in the circumferential direction of the shaft, and has a plurality of vanes provided on the outer circumference away from the shaft on a first plane intersecting the rotation axis. One or more rectifier elements are provided on the first surface of the heat sink, in a portion surrounded by multiple vanes, and are thermally connected to the heat sink via the first surface and connected to the second winding. The multiple vanes allow air to flow through the portion surrounded by the multiple vanes as the heat sink rotates in the circumferential direction.
[0009] According to one embodiment of the present invention, the power transmission device and motor device make it easier to dissipate heat.
[0010] Figure 1 is a block diagram showing an example configuration of a motor device according to one embodiment of the present invention. Figure 2 is a circuit diagram showing an example configuration of the inverter and power transmission device shown in Figure 1. Figure 3 is a perspective view showing an example configuration of the stator and shaft shown in Figure 1. Figure 4 is a cross-sectional view showing an example configuration of the stator and rotor shown in Figure 1. Figure 5 is a plan view showing an example configuration of the substrate of the stator and rotor shown in Figure 3. Figure 6 is a perspective view showing an example configuration of the rotating body shown in Figure 1. Figure 7 is an exploded perspective view showing an example configuration of the rotating body shown in Figure 6. Figure 8 is a perspective view showing an example configuration of the multiple blades shown in Figure 6. Figure 9 is an explanatory diagram showing an example of the implementation of the diode shown in Figure 7. Figure 10 is an explanatory diagram showing an example of power transmission operation in the power transmission device shown in Figure 1. Figure 11 is an explanatory diagram showing an example of heat dissipation operation in the power transmission device shown in Figure 1.
[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0012] <Embodiment> [Configuration Example] Figure 1 shows an example configuration of a motor device 1 equipped with a power transmission device according to an 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 the rotational speed. The DC power supply 9 is configured to supply DC power to the motor device 1. The motor device 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 device 1 comprises a drive unit 10 and a motor 70.
[0013] The drive unit 10 is configured to drive the motor 70. The drive unit 10 includes inverters 11 and 12, a power transmission device 20, 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 the windings 71B (described later) of the stator 71 of the motor 70.
[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 instructions from the control circuit 19. The inverter 12 then supplies this AC power to the winding 33 (described later) of the stator 30 of the power transmission device 20.
[0016] The power transmission device 20 is configured to supply power supplied from the inverter 12 to the windings 72B (described later) of the rotor 72 of the motor 70. The power transmission device 20 includes a stator 30, a rotor 40, a rotating body 50, and a shaft 24.
[0017] Figure 2 shows an example configuration of the inverter 12 and the power transmission device 20. Figure 2 also shows the DC power supply 9 and the windings 72B of the rotor 72 of the motor 70. The inverter 12 is connected to the DC power supply 9 via the voltage line L11 and the reference voltage line L12.
[0018] In this example, the inverter 12 is a full-bridge type circuit. The inverter 12 has switching elements SW1 to SW4 and a switching control circuit 18. Each of the switching elements SW1 to SW4 is configured using, for example, a field-effect transistor or an insulated-gate bipolar transistor. Switching element SW1 is provided in the path connecting the voltage line L11 and node N1 and is configured to perform switching operations based on a control signal supplied from the switching control circuit 18. Switching element SW2 is provided in the path connecting node N1 and reference voltage line L12 and is configured to perform switching operations based on a control signal supplied from the switching control circuit 18. Switching element SW3 is provided in the path connecting the voltage line L11 and node N2 and is configured to perform switching operations based on a control signal supplied from the switching control circuit 18. Switching element SW4 is provided in the path connecting node N2 and reference voltage line L12 and is configured to perform switching operations based on a control signal supplied from the switching control circuit 18. The switching control circuit 18 is configured to control the switching operation of switching elements SW1 to SW4 by supplying control signals to each of the switching elements SW1 to SW4 based on instructions from the control circuit 19.
[0019] The power transmission device 20 includes a winding 33, a winding 43, and a rectifier circuit 59. Winding 33 is provided on the stator 30, with one end connected to node N1 of the inverter 12 and the other end connected to node N2 of the inverter 12. Winding 43 is provided on the rotor 40, with one end connected to node N3 of the rectifier circuit 59 and the other end connected to node N4 of the rectifier circuit 59. Windings 33 and 43 constitute a so-called rotary transformer, and winding 43 is configured to receive AC power supplied from winding 33. The rectifier circuit 59 is provided on the rotating body 50 and is configured to rectify the AC power supplied from winding 43 of the rotor 40. The rectifier circuit 59 has four diodes D (diodes D1 to D4). The cathode of diode D1 is connected to voltage line L21, and its anode is connected to node N3. The cathode of diode D2 is connected to node N3, and its anode is connected to the reference voltage line L22. The cathode of diode D3 is connected to voltage line L21, and its anode is connected to node N4. The cathode of diode D4 is connected to node N4, and its anode is connected to the reference voltage line L22. Note that the rectifier circuit 59 is not limited to this configuration; instead, for example, four transistors may be used instead of four diodes to perform synchronous rectification. Voltage line L21 and reference voltage line L22 are connected to the winding 72B (described later) of the rotor 72 of the motor 70.
[0020] In this configuration, the inverter 12 converts the DC power supplied from the DC power supply 9 into AC power. The power transmission device 20 then transmits the AC power supplied from the inverter 12 from its stator 30 to its rotor 40, and rectifies the transmitted AC power. The power transmission device 20 then supplies the rectified power to the winding 72B (described later) of the rotor 72 of the motor 70. In this example, the power rectified by the rectifier circuit 59 is supplied directly to the winding 72B, but this is not the only option. Alternatively, for example, the power rectified by the rectifier circuit 59 may be supplied to the winding 72B via a stabilization circuit including a capacitor.
[0021] The control circuit 19 (Figure 1) is configured to control the operation of inverters 11 and 12 based on instructions from the external control device 8, control signals indicating the output current supplied from inverters 11 and 12, and control signals indicating the rotational speed supplied from motor 70. Specifically, the control circuit 19 controls the rotational speed of motor 70 by controlling the operation of inverter 11 based on instructions from the external control device 8 and control signals indicating the rotational speed of motor 70. Furthermore, the control circuit 19 controls the strength of the magnetic field generated by the rotor 72 of motor 70 by controlling the operation of inverter 12 based on the control signal indicating the rotational speed supplied from motor 70.
[0022] Motor 70 (Figure 1) is a wound-field synchronous motor. Motor 70 includes a stator 71, a rotor 72, and a sensor 73.
[0023] The stator 71 is a so-called stator and is fixed to a housing (not shown) of the motor 70. The stator 71 has a magnetic core 71A and windings 71B. Three-phase (U-phase, V-phase, W-phase) AC power generated by the inverter 11 is supplied to the windings 71B.
[0024] The rotor 72 is a so-called rotor and is configured to rotate the rotation axis AZ. The rotor 72 has a magnetic core 72A and windings 72B. Power rectified by the rectifier circuit 59 is supplied to the windings 72B.
[0025] The sensor 73 is configured to detect the rotational speed of the rotor 72. The sensor 73 then supplies a control signal indicating the rotational speed of the rotor 72 to the control circuit 19.
[0026] In this configuration, the motor device 1 controls the rotational speed and torque of the motor 70 based on the three-phase (U-phase, V-phase, W-phase) AC power generated by the inverter 11, and controls the torque of the motor 70 based on the single-phase AC power generated by the inverter 12. The motor device 1 also controls the magnetic field generated by the rotor 72 of the motor 70 based on the single-phase AC power generated by the inverter 12. For example, in the motor device 1, when the rotational speed of the motor 70 is slow, the magnetic field generated by the rotor 72 of the motor 70 is strengthened, and when the rotational speed of the motor 70 is fast, the magnetic field generated by the rotor 72 of the motor 70 is weakened. As a result, the motor device 1 can increase the efficiency of the motor 70 over a wide range of rotational speeds.
[0027] (Power transmission device 20) Figure 3 shows an example configuration of the stator 30 in the power transmission device 20. Figure 4 shows an example configuration of the stator 30 and rotor 40 in the power transmission device 20. Figure 5 shows an example configuration of the windings 33 of the stator 30 and the windings 34 of the rotor 40.
[0028] The stator 30 is fixed to a housing (not shown) of the motor device 1. As shown in Figures 3 and 4, the stator 30 has a magnetic core 31, a substrate 32, and windings 33.
[0029] The magnetic core 31 is constructed using a magnetic material such as ferrite. As shown in Figures 3 and 4, the magnetic core 31 is configured to surround the substrate 32 and the rotor 40. The magnetic core 31 has a magnetic core 31A and a magnetic core 31B. The magnetic cores 31A and 31B are arranged in this order in the direction opposite to the Z direction. Here, the Z direction is the axial direction of the rotation axis AZ, as shown in Figure 1, and is the direction from the motor 70 toward the power transmission device 20. As shown in Figures 3 and 4, the magnetic core 31 is provided with a through hole 33 for passing the shaft 24 through.
[0030] As shown in Figure 3, the magnetic core 31A has a ring shape in a plane intersecting the axial direction of the rotation axis AZ. As shown in Figure 4, the magnetic core 31A has a protrusion 31C on its outer circumference in the plane intersecting the axial direction of the rotation axis AZ that protrudes in the direction in which the magnetic core 31B is provided. Also, as shown in Figure 4, the magnetic core 31A has a protrusion 31D at its end near the shaft 24 that protrudes in the direction in which the magnetic core 31B is provided. These protrusions 31C and 31D have a ring shape in a plane intersecting the axial direction of the rotation axis AZ.
[0031] The magnetic core 31B, like the magnetic core 31A, has a ring shape in a plane intersecting the axial direction of the rotation axis AZ. Furthermore, like the magnetic core 31A, the magnetic core 31B has a protrusion 31C on its outer circumference in the plane intersecting the axial direction of the rotation axis AZ, projecting in the direction from which the magnetic core 31A is provided. This protrusion 31C has a ring shape in the plane intersecting the axial direction of the rotation axis AZ.
[0032] The magnetic cores 31A and 31B are connected such that the protrusions 31C of magnetic core 31A and magnetic core 31B are in contact with each other. In this way, a cavity is provided inside the magnetic core 31.
[0033] The substrate 32 is, for example, a printed circuit board (PCB). In this example, as shown in Figure 4, the substrate 32 is provided on the surface of the magnetic core 31A that faces the magnetic core 31B. The substrate 32 has a ring shape, as shown in Figure 5. The substrate 32 is positioned outside the ring-shaped protrusion 31D of the magnetic core 31, as shown in Figure 4.
[0034] As shown in Figure 5, the winding 33 is constructed using pattern wiring provided on the substrate 32 and is wound multiple times along the circumferential direction of the rotation axis AZ. In Figure 5, the area on the substrate 32 where the winding 33 is provided is shaded. The winding 33 may be provided on one of the two surfaces of the substrate 32, or on both surfaces. Also, if the substrate 32 is a multilayer substrate, the winding 33 may be constructed using pattern wiring inside the substrate 32. The winding 33 is connected to the inverter 12.
[0035] The rotor 40 is connected to the shaft 24 and configured to rotate about the rotation axis AZ. As shown in Figure 4, the rotor 40 is positioned so as to be sandwiched in the Z direction by the magnetic cores 31A and 31B of the stator 30. As shown in Figures 4 and 5, the rotor 40 has a substrate 42 and windings 43.
[0036] The substrate 42 is, for example, a printed circuit board. The substrate 42 is provided at a different position in the Z direction from the position where the substrate 32 of the stator 30 is provided. The substrate 42 has a circular shape, as shown in Figure 5. In this example, the size of the substrate 42 is approximately the same as the size of the substrate 32 of the stator 30.
[0037] As shown in Figure 5, the winding 43 is constructed using pattern wiring provided on the substrate 42 and is wound multiple times along the circumferential direction of the rotation axis AZ. In Figure 5, the area on the substrate 42 where the winding 43 is provided is shaded. The winding 43 may be provided on one of the two surfaces of the substrate 42, or on both surfaces. Also, if the substrate 42 is a multilayer substrate, the winding 43 may be constructed using pattern wiring inside the substrate 42. As shown in Figure 5, in this example, the area on the substrate 42 where the winding 43 is provided is approximately the same as the area on the substrate 32 of the stator 30 where the winding 33 is provided. The winding 43 is connected to the rectifier circuit 59.
[0038] Figure 6 shows one example configuration of the rotating body 50 in the power transmission device 20. Figure 7 shows one example configuration of the disassembled rotating body 50.
[0039] The rotating body 50 is connected to the shaft 24 and is configured to rotate about the rotation axis AZ. The rotating body 50 includes a heat sink 51, a substrate 52, and a fixing member 53.
[0040] The heat sink 51 is connected to the shaft 24 and configured to rotate about the rotation axis AZ. The heat sink 51 may be configured separately from the shaft 24 or integrally with the shaft 24. The heat sink 51 is made of a non-magnetic material, such as aluminum or stainless steel. However, it is not limited to this, and the heat sink 51 may be made of a magnetic material, such as carbon steel. The heat sink 51 has a circular shape in a plane intersecting the axial direction of the rotation axis AZ. As shown in Figure 7, the heat sink 51 has a plurality of blades 51A on the outer circumference away from the shaft 24 on the plane 51B of the heat sink 51 that intersects the rotation axis AZ.
[0041] Figure 8 shows one example configuration of multiple vanes 51A. For ease of explanation, Figure 8 shows the heat sink 51 cut at a plane intersecting the rotation axis AZ. The multiple vanes 51A are arranged at approximately equal intervals on the outer circumference of the heat sink 51. Each of the multiple vanes 51A has a surface that curves circumferentially as it moves away from the rotation axis AZ. However, this is not limited to this, and each of the multiple vanes 51A may be a flat surface. The multiple vanes 51A are arranged so that air flows radially from the inside to the outside of the heat sink 51 as the shaft 24 rotates circumferentially A around the rotation axis AZ.
[0042] As shown in Figures 7 and 8, the portion of surface 51B surrounded by the multiple blades 51A is provided with the four diodes D (diodes D1 to D4) shown in Figure 2.
[0043] Figure 9 shows an example of how the diode D is mounted on the rotating body 50. The diode D has multiple terminal electrodes EL1 and a heat dissipation electrode EL2. Note that only one electrode EL1 is shown in Figure 9.
[0044] The plurality of terminal electrodes EL1 are electrodes such as the anode and cathode of the diode D. The plurality of terminal electrodes EL1 are provided on the side surface of the package of the diode D, bent, and connected to the substrate 52. The anodes of the diodes D1 and D3 and the cathodes of the diodes D2 and D4 are connected to the winding 43 of the rotor 40 via the pattern wiring provided on this substrate 52. Also, the cathodes of the diodes D1 and D3 and the anodes of the diodes D2 and D4 are connected to the winding 72B of the motor 70 via the pattern wiring provided on this substrate 52.
[0045] The heat radiating electrode EL2 is an electrode for releasing the heat generated in the diode D to the outside. The heat radiating electrode EL2 is provided on the bottom surface of the package of the diode D. The diode D is provided such that the heat radiating electrode EL2 directly or indirectly contacts the surface 51B of the heat sink 51. For example, an insulating sheet may be provided between the diode D and the surface 51B of the heat sink 51. Thereby, the diode D is thermally connected to the heat sink 51 via the surface 51B of the heat sink 51. In this example, the diode D is fixed to the heat sink 51 by a screw 51C. Thus, since the diode D is thermally connected to the heat sink 51 via the surface 51B of the heat sink 51, the diode D can be effectively cooled.
[0046] Also, as described above, the plurality of blades 51A provided on the heat sink 51 cause air to flow in the radial direction from the inside to the outside of the heat sink 51 as the shaft 24 rotates in the circumferential direction A about the rotation axis AZ. Thereby, the air near the four diodes D surrounded by the plurality of blade portions flows toward the outside of the heat sink 51. As a result, in the power transmission device 20, the four diodes D can be effectively cooled.
[0047] The substrate 52 is, for example, a printed circuit board. The substrate 52 is provided with a hole 52A for passing the shaft 24, and the substrate 52 has a ring shape. Pattern wirings for connecting the rectifier circuit 59 to the winding 43 of the rotor 40 and the winding 72B of the motor 70 are formed on the substrate 52. The substrate 52 has four electrodes 52B. The pattern wiring of the substrate 52 is connected to the winding 43 of the rotor 40 and the winding 72B of the motor 70 via these four electrodes 52B.
[0048] The fixing member 53 is configured to fix the substrate 52 to the heat sink 51. The fixing member 53 has a ring shape and is made of, for example, metal. The fixing member 53, the substrate 52, and the heat sink 51 are arranged in this order. That is, the fixing member 53 is arranged so as to press the substrate 52 against the heat sink 51. Then, the fixing member 53, the substrate 52, and the heat sink 51 are fixed by a screw 53A.
[0049] The shaft 24 is connected to the rotor 72 of the motor 70 and is configured to rotate about the rotation axis AZ in accordance with the driving force generated by the motor 70. The shaft 24 may be directly connected to the rotor 72 of the motor 70 or may be indirectly connected via other components. Further, the shaft 24 may be formed integrally with the rotor 72 of the motor 70.
[0050] With this configuration, the power transmission device 20 transmits the AC power supplied from the inverter 12 from the stator 30 to the rotor 40 by non-contact transmission and rectifies the transmitted AC power. Then, the power transmission device 20 supplies the rectified power to the rotor 72 of the motor 70.
[0051] Here, the shaft 24 corresponds to a specific example of the "shaft" in one embodiment of the present disclosure. The stator 30 corresponds to a specific example of the "stator" in one embodiment of the present disclosure. The winding 33 corresponds to a specific example of the "first winding" in one embodiment of the present disclosure. The rotor 40 corresponds to a specific example of the "rotor" in one embodiment of the present disclosure. The winding 43 corresponds to a specific example of the "second winding" in one embodiment of the present disclosure. The heat sink 51 corresponds to a specific example of the "heat sink" in one embodiment of the present disclosure. The blade 51A corresponds to a specific example of the "blade" in one embodiment of the present disclosure. The surface 51B corresponds to a specific example of the "first surface" in one embodiment of the present disclosure. The diode D corresponds to a specific example of the "rectifier element" in one embodiment of the present disclosure. The bottom surface of the package of diode D corresponds to a specific example of the "second surface" in one embodiment of the present disclosure. The terminal electrode EL1 corresponds to a specific example of the "terminal electrode" in one embodiment of the present disclosure. The heat dissipation electrode EL2 corresponds to a specific example of the "heat dissipation electrode" in one embodiment of the present disclosure. The motor 70 corresponds to a specific example of the "motor" in one embodiment of the present disclosure. The stator 71 corresponds to a specific example of the "motor stator" in one embodiment of the present disclosure. The rotor 72 corresponds to a specific example of the "motor rotor" in one embodiment of the present disclosure.
[0052] [Operation and Function] Next, the operation and function of the motor device 1 of this embodiment will be described.
[0053] (Overall Operation Summary) The control circuit 19 controls the operation of inverters 11 and 12 based on instructions from the external control device 8, control signals indicating the output current supplied from inverters 11 and 12, and control signals indicating the rotational speed supplied from motor 70. Based on instructions from the control circuit 19, inverter 11 converts the DC power supplied from the DC power supply 9 into three-phase (U-phase, V-phase, W-phase) AC power and supplies this three-phase AC power to the windings 71B of the stator 71 of motor 70. Based on instructions from the control circuit 19, inverter 12 converts the DC power supplied from the DC power supply 9 into single-phase AC power and supplies this AC power to the windings 33 of the stator 30 of power transmission device 20. Power transmission device 20 transmits the AC power supplied from inverter 12 from the stator 30 to the rotor 40 by contactless transmission and rectifies the transmitted AC power. The power transmission device 20 then supplies the rectified power to the windings 72B of the rotor 72 of the motor 70. The motor 70 generates driving force, which is mechanical energy, based on the three-phase (U-phase, V-phase, W-phase) AC power supplied from the inverter 11. As a result, the shaft 24 rotates around the rotation axis AZ. The sensor 73 of the motor 70 supplies a control signal indicating the rotational speed of the motor 70 to the control circuit 19.
[0054] (Detailed Operation) Next, the operation and function of the power transmission device 20 of this embodiment will be described.
[0055] The power transmission device 20 can transmit power by contactless transmission. The power transmission operation is described below.
[0056] Figure 10 illustrates the power transmission operation in the power transmission device 20. The windings 33 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 closest to the shaft 24 and the portion of the magnetic core 31B closest to the shaft 24 are magnetically coupled to each other. As a result, the power transmission device 20 generates a magnetic path MP through the magnetic cores 31A and 31B, as shown in Figure 10. The windings 43 of the rotor 40 then generate AC power based on the magnetic field in this magnetic path MP and supply the generated AC power to the rectifier circuit 59. In this way, the power transmission device 20 can supply AC power to the rectifier circuit 59 by contactless transmission.
[0057] Thus, since power is transmitted by non-contact transmission in the power transmission device 20, reliability can be improved compared to, for example, the case where power is transmitted by contact transmission using slip rings and brushes.
[0058] The rectifier circuit 59 rectifies the AC power supplied from the winding 43 of the rotor 40 and supplies the rectified power to the winding 72B of the rotor 72 of the motor 70. As a result, a magnetic field is generated in the rotor 72 of the motor 70. The control circuit 19 strengthens the magnetic field generated by the rotor 72 of the motor 70 when the rotational speed of the motor 70 is slow, and weakens the magnetic field generated by the rotor 72 of the motor 70 when the rotational speed of the motor 70 is fast. As a result, the motor device 1 can increase the efficiency of the motor 70 over a wide range of rotational speeds.
[0059] Furthermore, in the power transmission device 20, such power transmission operations can cause, for example, the diode D of the rotating body 50 to generate heat. Since the diode D is thermally connected to the heat sink 51 via the surface 51B of the heat sink 51, it can effectively dissipate heat. In addition, the heat sink 51 rotates around the rotation axis AZ, causing air to flow around the diode D, thus effectively dissipating heat from the diode D.
[0060] Figure 11 illustrates the airflow around the rotating body 50. When the shaft 24 rotates in the circumferential direction A, the multiple vanes 51A of the heat sink 51 rotate in the circumferential direction A around the rotation axis AZ. As a result, air flows from outside the rotating body 50 through the holes 52A in the substrate 52 into the cavity inside the rotating body 50, as indicated by the dashed arrows in Figure 11. The air in the cavity inside the rotating body 50 then flows radially toward the outside of the heat sink 51. This causes heated air to flow around the four diodes D inside the rotating body 50 in the power transmission device 20. Consequently, the power transmission device 20 can dissipate heat from the diodes D.
[0061] Thus, the power transmission device 20 includes a shaft 24 rotatable around a rotation axis AZ, a stator 30 spaced apart from the shaft 24 and having a first winding (winding 33) wound in the circumferential direction of the shaft 24, a rotor 40 connected to the shaft 24 and rotatable in the circumferential direction of the shaft 24 and having a second winding (winding 43) wound in the circumferential direction of the shaft 24, and a motor connected to the shaft 24 at a position in the axial direction of the shaft 24 different from the position where the rotor 40 is installed. The heat sink 51 is rotatable in the circumferential direction of the shaft 24 and has a plurality of blades 51A provided on the outer circumference away from the shaft 24 on a first surface (surface 51B) that intersects with the rotation axis AZ. The heat sink 51 also includes one or more rectifier elements (four diodes D) provided on the portion of the first surface (surface 51B) of the heat sink 51 surrounded by the plurality of blades 51A, thermally connected to the heat sink 51 via the first surface (surface 51B), and connected to a second winding (winding 43). The plurality of blades 51A allow air to flow in the portion surrounded by the plurality of blades 51A as the heat sink 51 rotates in the circumferential direction. The diodes D are thermally connected to the heat sink 51 via the surface 51B of the heat sink 51, so the diodes D can be effectively heated. Furthermore, as the heat sink 51 rotates around the rotation axis AZ, it allows air to flow around the diodes D, so the diodes D can be effectively heated. As a result, the power transmission device 20 can dissipate heat more easily.
[0062] The power transmission device 20 further includes a substrate 52 connected to the heat sink 51, facing the first surface (surface 51B) of the heat sink 51, and having pattern wiring connecting one or more rectifier elements (four diodes D) to a second winding (winding 43). This allows the four diodes D in the power transmission device 20 to be connected to the winding 43 via the pattern wiring on the substrate 52.
[0063] In the power transmission device 20, each of the one or more rectifier elements (four diodes D) has a heat dissipation electrode EL2 provided on a second surface and a terminal electrode EL1 provided on a surface other than the second surface. The terminal electrode EL1 is connected to the pattern wiring of the substrate 52, and the heat dissipation electrode EL2 is thermally connected to the heat sink 51 via the first surface 51B. As a result, the power transmission device 20 can effectively dissipate heat from the diodes D. In general, diodes are mounted on a printed circuit board, and both the terminal electrode EL1 and the heat dissipation electrode EL2 are connected to the printed circuit board. Since the printed circuit board is made of resin, there is a possibility that the diodes cannot dissipate heat sufficiently. On the other hand, in the power transmission device 20, the terminal electrode EL1 is connected to the substrate 52, and the heat dissipation electrode EL2 is connected to the heat sink 51. As a result, the heat dissipation of the diodes D can be improved.
[0064] [Effects] As described above, this embodiment includes a shaft rotatable around a rotation axis, a stator spaced apart from the shaft and having a first winding wound in the circumferential direction of the shaft, a rotor connected to the shaft and rotatable in the circumferential direction of the shaft and having a second winding wound in the circumferential direction of the shaft, a heat sink connected to the shaft at a position in the axial direction of the shaft different from the position where the rotor is installed, rotatable in the circumferential direction of the shaft and having a plurality of vanes provided on the outer circumference of a first surface intersecting the rotation axis and away from the shaft, and one or more rectifier elements provided on the portion of the first surface of the heat sink surrounded by the plurality of vanes, thermally connected to the heat sink via the first surface and connected to the second winding. The plurality of vanes are arranged so that air can flow through the portion surrounded by the plurality of vanes as the heat sink rotates in the circumferential direction. This makes heat dissipation easier.
[0065] In this embodiment, the system is further equipped with a substrate 52 that is connected to the heat sink and is connected to the heat sink so as to face the first surface of the heat sink, and has pattern wiring connecting one or more rectifier elements to the second winding. This allows four diodes to be connected to the winding via the pattern wiring on the substrate.
[0066] In this embodiment, each of the one or more rectifier elements has a heat dissipation electrode provided on a second surface and a terminal electrode provided on a surface other than the second surface. The terminal electrode is connected to the pattern wiring of the substrate 52, and the heat dissipation electrode is thermally connected to the heat sink via the first surface. This makes heat dissipation easier.
[0067] Although the present invention has been described above with reference to embodiments, the present invention is not limited to these embodiments and various modifications are possible.
[0068] For example, the arrangement and shape of the stator, rotor, magnetic core, substrate, winding, rotating body, and diode shown in the above embodiments are examples only and are not limited to the disclosed arrangements and shapes.
[0069] The effects described herein are illustrative only, and the effects of this disclosure are not limited to those described herein. Therefore, other effects may be obtained with respect to this disclosure.
[0070] Furthermore, this disclosure may take the following forms:
[0071] (1) A power transmission device comprising: a shaft rotatable about a rotation axis; a stator spaced apart from the shaft and having a first winding wound in the circumferential direction of the shaft; a rotor connected to the shaft and rotatable in the circumferential direction of the shaft and having a second winding wound in the circumferential direction of the shaft; a heat sink connected to the shaft at a position in the axial direction of the shaft different from the position where the rotor is provided, rotatable in the circumferential direction of the shaft and having a plurality of vanes provided on the outer circumference of a first surface intersecting the rotation axis, away from the shaft; and one or more rectifier elements provided on the first surface of the heat sink in the area surrounded by the plurality of vanes, thermally connected to the heat sink via the first surface, and connected to the second winding, wherein the plurality of vanes allow air to flow in the area surrounded by the plurality of vanes as the heat sink rotates in the circumferential direction. (2) The power transmission device according to (1), further comprising a substrate connected to the heat sink and connected to the heat sink so as to face the first surface of the heat sink, and having pattern wiring connecting the one or more rectifier elements and the second winding. (3) The power transmission device according to (2), wherein each of the one or more rectifier elements has a heat dissipation electrode provided on the second surface and a terminal electrode provided on a surface other than the second surface, the terminal electrode is connected to the pattern wiring of the substrate, and the heat dissipation electrode is thermally connected to the heat sink via the first surface.(4) 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 and rotatable about a rotation axis; a stator spaced apart from the shaft and having a first winding wound in the circumferential direction of the shaft; a rotor connected to the shaft and rotatable in the circumferential direction of the shaft and having a second winding wound in the circumferential direction of the shaft; a heat sink connected to the shaft at a position in the axial direction of the shaft different from the position where the rotor is provided, rotatable in the circumferential direction of the shaft and having a plurality of vanes provided on the outer circumference of a first surface intersecting the rotation axis and away from the shaft; and one or more rectifier elements provided on the first surface of the heat sink in a portion surrounded by the plurality of vanes, thermally connected to the heat sink via the first surface and connected to the second winding. The motor device is such that the plurality of blades can circulate air in the area surrounded by the plurality of blades as the heat sink rotates in the circumferential direction.
Claims
1. A power transmission device comprising: a shaft rotatable about a rotation axis; a stator spaced apart from the shaft and having a first winding wound in the circumferential direction of the shaft; a rotor connected to the shaft and rotatable in the circumferential direction of the shaft and having a second winding wound in the circumferential direction of the shaft; a heat sink connected to the shaft at a position in the axial direction of the shaft different from the position where the rotor is provided, rotatable in the circumferential direction of the shaft, and having a plurality of vanes provided on the outer circumference of a first surface intersecting the rotation axis, away from the shaft; and one or more rectifier elements provided on the portion of the first surface of the heat sink surrounded by the plurality of vanes, thermally connected to the heat sink via the first surface, and connected to the second winding, wherein the plurality of vanes allow air to flow in the portion surrounded by the plurality of vanes as the heat sink rotates in the circumferential direction.
2. The power transmission device according to claim 1, further comprising a substrate connected to the heat sink, and connected to the heat sink so as to face the first surface of the heat sink, and having pattern wiring connecting the one or more rectifier elements and the second winding.
3. The power transmission device according to claim 2, wherein each of the one or more rectifier elements has a heat dissipation electrode provided on a second surface and a terminal electrode provided on a surface other than the second surface, the terminal electrode is connected to the pattern wiring of the substrate, and the heat dissipation electrode is thermally connected to the heat sink via the first surface.
4. A motor comprising: a motor stator including a first motor magnetic core and a first motor winding; a motor rotor including a second motor magnetic core and a second motor winding; a shaft connected to the motor rotor and rotatable about a rotation axis; a stator spaced apart from the shaft and having a first winding wound in the circumferential direction of the shaft; a rotor connected to the shaft, rotatable in the circumferential direction of the shaft and having a second winding wound in the circumferential direction of the shaft; a heat sink connected to the shaft at a position in the axial direction of the shaft different from the position where the rotor is provided, rotatable in the circumferential direction of the shaft and having a plurality of vanes provided on the outer circumference of a first surface intersecting the rotation axis and away from the shaft; and one or more rectifier elements provided on the first surface of the heat sink in a portion surrounded by the plurality of vanes, thermally connected to the heat sink via the first surface and connected to the second winding. The motor device is such that the plurality of blades can circulate air in the area surrounded by the plurality of blades as the heat sink rotates in the circumferential direction.