WO2024171299A1 - Power transmission device and motor device - Google Patents

Abstract

A power transmission device according to one embodiment of the present invention comprises: a magnetic core that has a ring shape including a through-hole through which a shaft passes, includes a cavity therein along the circumferential direction of a rotary shaft in the shaft, is provided along the circumferential direction on a first surface contacting the through-hole, and has a first opening connecting the through-hole and the cavity; a first winding that is provided in the cavity and wound along the circumferential direction; a rotating member that is provided at a position corresponding to the first opening in the axial direction of the rotary shaft, and is capable of turning in the circumferential direction inside the cavity in accordance with the rotation of the shaft; a second winding that is provided to the rotating member and wound along the circumferential direction; and a first magnetic body that is provided along the circumferential direction at a portion of the rotating member corresponding to the first opening of the magnetic core.

Description

Power transmission device and motor device

The present invention relates to a power transmission device that transmits power contactlessly, and a motor device equipped with such a power transmission device.

For example, one type of motor is the electrically excited synchronous motor (EESM). This motor has a stator with windings wound around it, and a rotor with windings wound around it. With this type of 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.

By the way, there are devices that can transmit power between a stator and a rotor. For example, Patent Document 1 discloses a rotary transformer that has a stator wound with a winding and a rotor wound with a winding, and can transmit power between the stator and the rotor.

JP 2002-75760 A

In motor devices, high motor efficiency is desirable, and further improvements in motor efficiency are expected.

It is desirable to provide a power transmission device and a motor apparatus that can increase the efficiency of a motor.

The power transmission device according to one embodiment of the present invention includes a magnetic core, a first winding, a rotating member, a second winding, and a first magnetic body. The magnetic core has a ring shape including a through hole through which the shaft passes, includes a cavity inside along the circumferential direction of the rotating axis of the shaft, and has a first opening provided along the circumferential direction on a first surface that contacts the through hole. The first opening connects the through hole and the cavity. The first winding is provided in the cavity and wound along the 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 capable of rotating circumferentially inside the cavity in response to rotation of the shaft. The second winding is provided on the rotating member and wound along the circumferential direction. The first magnetic body is provided along the circumferential direction in a portion of the rotating member that corresponds to the first opening of the magnetic core.

A motor device according to one embodiment of the present invention includes 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 includes a motor stator including a first motor magnetic core and a first motor winding, and a motor rotor including a second motor magnetic core and a second motor winding. The shaft is connected to the motor rotor. The magnetic core has a ring shape including a through hole through which the shaft passes, includes a cavity along the circumferential direction of the rotating axis of the shaft, and has a first opening provided along the circumferential direction on a first surface that contacts the through hole. The first opening connects the through hole and the cavity. The first winding is connected to the inverter, provided in the cavity, and wound along the circumferential direction. The rotating member is provided at a position corresponding to the first opening in the axial direction of the rotating axis, and is capable of rotating circumferentially inside the cavity in response to rotation of the shaft. The second winding is provided on the rotating member and wound in the circumferential direction. The first magnetic body is provided in the circumferential direction in a portion of the rotating member that corresponds to the first opening of the magnetic core. The rectifier circuit is provided in a path that connects the second winding and the second motor winding.

The power transmission device and motor device according to one embodiment of the present invention can improve the efficiency of the motor.

FIG. 1 is a block diagram showing an example of the configuration of a motor device according to an embodiment of the present invention. FIG. 2 is a perspective view illustrating a configuration example of the power transmission device illustrated in FIG. FIG. 3 is a cross-sectional view illustrating an example of a configuration of the power transmission device illustrated in FIG. 2 . FIG. 4 is an explanatory diagram showing an example of the configuration of the stator shown in FIG. FIG. 5 is an explanatory diagram showing an example of the configuration of the rotor shown in FIG. FIG. 6 is an explanatory diagram illustrating an operation example of the power transmission device illustrated in FIG. 3 . FIG. 7 is an explanatory diagram illustrating an example of magnetic flux in the power transfer device illustrated in FIG. 3 . FIG. 8 is an explanatory diagram illustrating an example of magnetic flux in a power transfer device according to a reference example. FIG. 9 is an explanatory diagram illustrating a configuration example of a rotor according to a modified example. FIG. 10 is an explanatory diagram showing a configuration example of a rotor according to another modified example. FIG. 11 is a cross-sectional view illustrating a configuration example of a power transmission device according to another modified example. FIG. 12 is a perspective view illustrating a configuration example of a power transmission device according to another modified example. FIG. 13 is a cross-sectional view illustrating an example of a configuration of the power transmission device illustrated in FIG. FIG. 14 is a cross-sectional view illustrating a configuration example of a power transmission device according to another modified example. FIG. 15 is an explanatory diagram illustrating a configuration example of the rotor shown in FIG. FIG. 16 is a diagram illustrating an example of magnetic flux in the power transfer device illustrated in FIG. FIG. 17 is a cross-sectional view illustrating a configuration example of a power transmission device according to another modified example. FIG. 18 is a cross-sectional view illustrating a configuration example of a power transmission device according to another modified example. FIG. 19 is an explanatory diagram illustrating one configuration example of the rotor shown in FIG. FIG. 20 is a cross-sectional view illustrating a configuration example of a power transmission device according to another modified example. FIG. 21 is a cross-sectional view illustrating a configuration example of a power transmission device according to another modified example. FIG. 22 is an explanatory diagram illustrating a configuration example of the rotor shown in FIG. 21. In FIG. FIG. 23 is an explanatory diagram illustrating an operation example of the power transmission device illustrated in FIG. 21. In FIG. FIG. 24 is a cross-sectional view illustrating a configuration example of a power transmission device according to another modified example. FIG. 25 is an explanatory diagram illustrating a configuration example of the rotor shown in FIG. FIG. 26 is a cross-sectional view illustrating a configuration example of a power transmission device according to another modified example.

The following describes in detail the embodiments of the present invention with reference to the drawings.

<Embodiment>
[Configuration example]
1 shows an example of a configuration of a motor device 1 including 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 source 9. The external control device 8 is configured to instruct the motor device 1 on a rotation speed. The DC power source 9 is configured to supply DC power to the motor device 1. The motor device 1 is configured to generate a driving force, which is mechanical energy, based on an instruction from the external control device 8, using the DC power supplied from the DC power source 9. The motor device 1 includes a drive unit 10 and a motor 30.

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

The inverter 11 is configured to convert the DC power supplied from the DC power source 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 31B (described below) of the stator 31 of the motor 30.

The inverter 12 is configured to convert the DC power supplied from the DC power source 9 into single-phase AC power based on instructions from the control circuit 19. The inverter 12 then supplies this AC power to a winding 21B (described below) of a stator 21 of the power transmission device 20.

The power transmission device 20 is configured to supply AC power to the rectifier circuit 14 by non-contact transmission. The power transmission device 20 has a stator 21, a rotor 22, and a shaft 24.

FIG. 2 shows an example of the configuration of the power transmission device 20. FIG. 3 shows an example of the cross-sectional structure of the power transmission device 20 in a plane including the rotation axis AZ. FIG. 4 shows an example of the configuration of the stator 21. FIG. 4 also shows the cross-sectional structure of the stator 21 in a plane including the rotation axis AZ in the direction of the IV-IV arrows. FIG. 5 shows an example of the configuration of the rotor 22. FIG. 5 also shows the cross-sectional structure of the rotor 22 in a plane including the rotation axis AZ in the direction of the V-V arrows.

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

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, sandwiching the rotor 22, at a predetermined distance apart. Here, the Z direction is the extension direction of the rotation axis AZ, and 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 a ring-shaped magnetic member having a through hole 120 through which the shaft 24 passes, and has a flat plate shape in this example. The magnetic core 21A2 is a ring-shaped magnetic member having a through hole 120 through which the shaft 24 passes. The magnetic core 21A2 has a groove-shaped recess 121 on the surface S21 (Figures 3 and 4) facing the rotor 22, along the circumferential direction A (Figure 4) of the rotation axis AZ. With this configuration, magnetic core 21A, which has magnetic cores 21A1 and 21A2, has a cavity 122 along the circumferential direction A, an opening 123 that connects the inner space of magnetic core 21A in the radial direction of rotation axis AZ (horizontal direction in FIG. 3) to this cavity 122, and an opening 124 that connects the outer space of magnetic core 21A in the radial direction to this cavity 122.

Winding 21B is wound multiple times around recess 121 of magnetic core 21A2. Winding 21B is connected to inverter 12, for example, via a hole (not shown) provided in magnetic core 21A2.

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

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.

The winding 22B is configured using a pattern wiring provided on the substrate 22A, and is wound multiple times along the circumferential direction A (FIG. 5) of the rotation axis AZ. The winding 22B is configured using a metal material such as copper. In this example, the winding 22B is provided on both sides of the substrate 22A. However, this is not limited to this, and the winding 22B may be provided on one of the two sides of the substrate 22A. Furthermore, if the substrate 22A is a multi-layer substrate, the winding 22B may be configured using a pattern wiring inside the substrate 22A. One end and the other end of the winding 22B are connected to the rectifier circuit 14 via a portion 22D (described later) of the substrate 22A and a wiring (not shown) provided on the shaft 24.

The magnetic body 22C is made of a magnetic material such as ferrite, and is provided at a position of the rotor 22 corresponding to the opening 123 of the stator 21, as shown in FIG. 3. As shown in FIG. 5, the magnetic body 22C is provided so as to extend along the circumferential direction A of the rotation axis AZ. In this example, the magnetic body 22C has the shape of the letter "C". Specifically, the substrate 22A has a cutout portion in the shape of the letter "C", and the magnetic body 22C is fitted into the cutout portion of the substrate 22A. The part of the substrate 22A that is inside the magnetic body 22C and the part that is outside the magnetic body 22C are connected by the part 22D of the substrate 22A. However, this is not limited to this, and the magnetic body 22C may have a ring shape. In this case, for example, an insulating film may be provided on a part of the surface of the magnetic body 22C, and wiring that connects 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 width (horizontal direction in FIG. 3) of the magnetic body 22C is the same as the width of the protrusion near the opening 123 of the two protrusions on either side of the recess 121 in the radial direction of the magnetic core 21A2.

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

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

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

The rectifier circuit 14 (FIG. 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 (described later) of the rotor 32 of the motor 30. Although not shown, the rectifier circuit 14 is connected to the shaft 24. That is, the winding 22B and the rotor 32 of the motor 30 are connected to the shaft 24, and therefore the rectifier circuit 14 is also connected to the shaft 24. Note that in this example, the power rectified by the rectifier circuit 14 is directly supplied to the winding 32B, but this is not limited to this. Instead, for example, the power rectified by the rectifier circuit 14 may be supplied to the winding 32B via a stabilizing circuit including a capacitor.

The control circuit 19 is configured to control the operation of the inverters 11, 12 based on instructions from the external control device 8 and a control signal indicating the rotation speed supplied from the motor 30. Specifically, the control circuit 19 controls the operation of the inverter 11 based on instructions from the external control device 8 and a control signal indicating the rotation speed of the motor 30, thereby controlling the rotation speed of the motor 30. The control circuit 19 also controls the strength 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 rotation speed supplied from the motor 30. Specifically, the control circuit 19 is configured to strengthen the magnetic field generated by the rotor 32 of the motor 30 when the rotation speed of the motor 30 is slow, and to weaken the magnetic field generated by the rotor 32 of the motor 30 when the rotation speed of the motor 30 is fast.

The motor 30 is a wound field type synchronous motor. The motor 30 has a stator 31, a rotor 32, and a sensor 33.

The stator 31 is a so-called stator, and is fixed to a housing (not shown) of the motor 30. The stator 31 has a magnetic core 31A and a winding 31B. The winding 31B is supplied with three-phase (U-phase, V-phase, W-phase) AC power generated by the inverter 11.

The rotor 32 is a so-called rotor, and is configured to rotate the rotation axis AZ. The rotor 32 has a magnetic core 32A and a winding 32B. A signal rectified by the rectifier circuit 14 is supplied to the winding 32B.

The sensor 33 is configured to detect the rotation speed of the rotor 32. The sensor 33 is configured to supply a control signal indicating the rotation speed of the rotor 32 to the control circuit 19.

With this configuration, the motor device 1 controls the rotation speed of the motor 30 based on the three-phase (U-phase, V-phase, W-phase) AC power generated by the inverter 11, and controls the magnetic field generated by the rotor 32 of the motor 30 based on the single-phase AC power generated by the inverter 12. For example, when the rotation speed of the motor 30 is slow, the motor device 1 strengthens the magnetic field generated by the rotor 32 of the motor 30, and when the rotation speed of the motor 30 is fast, the magnetic field generated by the rotor 32 of the motor 30 is weakened. This makes it possible for the motor device 1 to increase the efficiency of the motor 30 over a wide range of rotation speeds.

Here, the shaft 24 corresponds to a specific example of a "shaft" in an embodiment of the present disclosure. The rotation axis AZ corresponds to a specific example of a "rotation axis" in an embodiment of the present disclosure. The magnetic core 21A corresponds to a specific example of a "magnetic core" in an embodiment of the present disclosure. The cavity 122 corresponds to a specific example of a "cavity" in an embodiment of the present disclosure. The opening 123 corresponds to a specific example of a "first opening" in an embodiment of the present disclosure. The winding 21B corresponds to a specific example of a "first winding" in an embodiment of the present disclosure. The substrate 22A corresponds to a specific example of a "rotating member" in an embodiment of the present disclosure. The winding 22B corresponds to a specific example of a "second winding" in an embodiment of the present disclosure. The magnetic body 22C corresponds to a specific example of a "first magnetic body" in an embodiment of the present disclosure. The opening 124 corresponds to a specific example of a "second opening" in an embodiment of the present disclosure. The magnetic body 22E corresponds to a specific example of a "second magnetic body" in an embodiment of the present disclosure.

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

[Actions and Functions]
Next, the operation and function of the motor device 1 of this embodiment will be described.

(Overall operation overview)
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 rotation speed supplied from the motor 30. The inverter 11 converts the DC power supplied from the DC power source 9 into three-phase (U-phase, V-phase, W-phase) AC power based on instructions from the control circuit 19, and supplies the three-phase AC power to the winding 31B of the stator 31 of the motor 30. The inverter 12 converts the DC power supplied from the DC power source 9 into single-phase AC power based on instructions from the control circuit 19, and supplies the 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 by non-contact transmission. The rectifier circuit 14 rectifies the AC power supplied from the winding 22B of the rotor 22, and supplies the rectified power to the winding 32B of the rotor 32 of the motor 30. The motor 30 generates a driving force, which is mechanical energy, based on the three-phase (U-phase, V-phase, W-phase) AC power supplied from the inverter 11. This causes the shaft 24 to rotate about the rotation axis AZ. The sensor 33 of the motor 30 supplies a control signal indicating the rotation speed of the motor 30 to the control circuit 19.

[Actions and Functions]
Next, the operation and function of the power transfer device 20 of the present embodiment will be described.

AC power is supplied from the inverter 12 to the windings 21B of the stator 21 of the power transmission device 20. The rotor 22 rotates around the rotation axis AZ in, for example, the circumferential direction A shown in FIG. 2.

FIG. 6 shows a cross-sectional view of the stator 21 and rotor 22 in the power transmission device 20. 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 protruding portions of the magnetic cores 21A1 and 21A2 near the opening 123 are magnetically coupled to each other via the magnetic material 22C, and near the opening 124, the protruding portions of the magnetic cores 21A1 and 21A2 near the opening 124 are magnetically coupled to each other via the magnetic material 22E.

Figure 7 shows an example of magnetic flux at openings 123 and 124 of power transmission device 20. Note that part of power transmission device 20 is omitted in Figure 7. Leakage magnetic flux occurs near openings 123 and 124. The direction of this leakage magnetic flux changes depending on the polarity of the AC power. In this example, leakage magnetic flux occurs from magnetic core 21A2 to magnetic body 22C near opening 123, and leakage magnetic flux occurs from magnetic body 22C to magnetic core 21A1. In this way, magnetic cores 21A1 and 21A2 are magnetically coupled to each other via magnetic body 22C near opening 123. Also, in this example, leakage magnetic flux occurs from magnetic core 21A1 to magnetic body 22E near opening 124, and leakage magnetic flux occurs from magnetic body 22E to magnetic core 21A2. In this way, magnetic core 21A1 and magnetic core 21A2 are magnetically coupled to each other via magnetic body 22E near opening 124.

In this way, in the power transmission device 20, as shown in FIG. 6, a magnetic path MP is generated that passes through the magnetic core 21A1, the magnetic body 22C, the magnetic core 21A2, and the magnetic body 22E.

Then, the winding 22B of the rotor 22 generates AC power based on the magnetic field in this magnetic path 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 by non-contact transmission.

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

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

In this way, in the power transmission device 20, the rotor 22 is constructed using a substrate 22A on which the windings 22B are provided. This allows the rotor 22 to be made lighter than when the rotor is constructed using a rotor core as in Patent Document 1, for example, and therefore the moment of rotation can be reduced, thereby reducing the inertial force.

Furthermore, in the power transmission device 20, the provision of the magnetic body 22C makes it possible to suppress the spread of leakage magnetic flux near the opening 123, thereby reducing the possibility of the leakage magnetic flux entering the shaft 24 or the winding 22B. Furthermore, the provision of the magnetic body 22E makes it possible to suppress the spread of leakage magnetic flux near the opening 124, thereby reducing the possibility of the leakage magnetic flux entering the winding 22B. As a result, in the power transmission device 20, energy loss can be reduced, and the efficiency of the motor can be increased.

That is, for example, as shown in FIG. 8, when the magnetic body 22C is not provided, a gap G is provided between the magnetic core 21A1 and the protruding portion near the opening 123 of the magnetic core 21A2, so the gap G becomes longer. As a result, as shown in FIG. 8, the leakage magnetic flux can spread in the radial direction (horizontal direction in FIG. 8). When the leakage magnetic flux enters the shaft 24, an eddy current is generated in the shaft 24, causing energy loss. When the leakage magnetic flux enters the winding 22B, an eddy current is generated in the winding 22B, causing energy loss. Similarly, when the magnetic body 22E is not provided, a gap G is provided between the magnetic core 21A1 and the protruding portion near the opening 124 of the magnetic core 21A2, so the gap G becomes longer. As a result, as shown in FIG. 8, the leakage magnetic flux can spread in the radial direction (horizontal direction in FIG. 8). When the leakage magnetic flux enters the winding 22B, an eddy current is generated in the winding 22B, causing energy loss.

On the other hand, in the power transmission device 20, the magnetic bodies 22C and 22E are provided, so that the gap G can be shortened, and the spread of leakage magnetic flux in the radial direction (horizontal direction in FIG. 7) can be suppressed. This reduces the possibility that leakage magnetic flux will enter the shaft 24 or winding 22B, thereby reducing energy loss and increasing the efficiency of the motor.

Thus, the power transmission device 20 includes a magnetic core 21A having a ring shape including a through hole 120 through which the shaft 24 passes, a cavity 122 extending along the circumferential direction A of the rotation axis AZ of the shaft 24, a first opening (opening 123) provided along the circumferential direction A on a first surface in contact with the through hole 120 and connecting the through hole 120 and the cavity 122, a first winding (winding 21B) provided in the cavity 122 and wound along the circumferential direction A, and a first winding (winding 21C) provided around the rotation axis AZ. The power transmission device 20 includes a substrate 22A that is provided at a position corresponding to the first opening (opening 123) in the AZ axial direction and can rotate in the circumferential direction A inside the cavity 122 in response to the rotation of the shaft 24, a second winding (winding 22B) that is provided on the substrate 22A and wound along the circumferential direction A, and a first magnetic body (magnetic body 22C) that is provided along the circumferential direction A in a portion of the substrate 22A that corresponds to the first opening (opening 123) of the magnetic core 21A. This makes it possible to suppress the spread of leakage magnetic flux near the opening 123, and to reduce the possibility that leakage magnetic flux will enter the shaft 24 or the winding 22B. As a result, the power transmission device 20 can reduce energy loss and increase the efficiency of the motor.

The power transmission device 20 further includes a second magnetic body (magnetic body 22E), and the magnetic core 21A has a second opening (opening 124) provided in a second surface opposite to the first surface in the radial direction of the rotation axis AZ at a position corresponding to the first opening (opening 123) in the axial direction, and the second magnetic body (magnetic body 22E) is provided along the circumferential direction A in a portion of the substrate 22A corresponding to the second opening (opening 124) of the magnetic core 21A. This makes it possible to suppress the spread of leakage magnetic flux near the opening 124, and to reduce the possibility of leakage magnetic flux entering the winding 22B. As a result, the power transmission device 20 can reduce energy loss and increase the efficiency of the motor.

[effect]
As described above, in this embodiment, the motor includes a magnetic core having a ring shape including a through hole through which the shaft passes, including a cavity therein that runs along the circumferential direction of the rotating axis of the shaft, and having a first opening that is arranged along the circumferential direction on a first surface that contacts the through hole and connects the through hole and the cavity, a first winding that is arranged in the cavity and wound along the circumferential direction, a substrate that is arranged at a position corresponding to the first opening in the axial direction of the rotating shaft and can rotate circumferentially inside the cavity in response to rotation of the shaft, a second winding that is arranged on the substrate and wound along the circumferential direction, and a first magnetic body that is arranged along the circumferential direction in the portion of the substrate that corresponds to the first opening of the magnetic core, thereby improving the efficiency of the motor.

In this embodiment, a second magnetic body is further provided, and the magnetic core has a second opening provided on a second surface opposite the first surface in the radial direction of the rotating shaft, at a position corresponding to the first opening in the axial direction, and the second magnetic body is provided along the circumferential direction in a portion of the substrate corresponding to the second opening of the magnetic core, thereby improving the efficiency of the motor.

[Modification 1]
In the above embodiment, the magnetic body 22C is configured using one magnetic body, as shown in Fig. 5, for example, but is not limited to this. Instead, the magnetic body 22C may be configured using a plurality of magnetic bodies, as shown in Fig. 9. In the example of Fig. 9, the magnetic body 22C is configured using two magnetic bodies.

[Modification 2]
In the above embodiment, the magnetic body 22E is provided as shown in, for example, FIGS. 3 and 5, but the present invention is not limited to this. Alternatively, for example, as shown in FIG. 10, the magnetic body 22E may not be provided.

[Modification 3]
In the above embodiment, for example, as shown in Fig. 3, the width of the magnetic body 22C in the radial direction (horizontal direction in Fig. 3) is set to be the same as the width of the convex part near the opening 123 of the two convex parts on both sides of the recess 121 in the radial direction of the magnetic core 21A2, but this is not limited to this. Instead of this, for example, as shown in Fig. 11, the width of the magnetic body 22C in the radial direction (horizontal direction in Fig. 11) may be wider than the width of the convex part near the opening 123 of the two convex parts on both sides of the recess 121 in the radial direction of the magnetic core 21A2.

Similarly, the radial width (horizontal direction in FIG. 3) of magnetic body 22E is the same as the width of the convex portion near opening 124 of the two convex portions on both sides of recess 121 in the radial direction of magnetic core 21A2, but is not limited to this. Instead, for example, as shown in FIG. 11, the radial width (horizontal direction in FIG. 11) of magnetic body 22E may be wider than the width of the convex portion near opening 124 of the two convex portions on both sides of recess 121 in the radial direction of magnetic core 21A2.

[Modification 4]
In the above embodiment, the magnetic core 21A has the opening 123 and the opening 124, as shown in FIG. 3, but the present invention is not limited thereto. Instead, the magnetic core 21A may have only one opening 123, as shown in FIG. 12 and FIG. 13. In this example, as shown in FIG. 13, the outer part of the magnetic core 21A1 in the radial direction (horizontal direction in FIG. 13) is bent in the Z direction and connected to the magnetic core 21A2 at the connecting part 125. In the manufacturing process of the power transmission device 20, the magnetic core 21A1, the rotor 22, and the magnetic core 21A2 are arranged in this order in the Z direction, the magnetic core 21A1, the rotor 22, and the magnetic core 21A2 are brought close to each other, and the magnetic core 21A1 and the magnetic core 21A2 are bonded to each other at the connecting part 125, for example. In the power transmission device 20, the opening 124 is not provided, so there is no leakage magnetic flux at the opening 124, and therefore energy loss can be reduced and the efficiency of the motor can be improved.

[Modification 5]
In the above embodiment, the magnetic bodies 22C and 22E are fitted into the notches in the substrate 22A as shown in FIG. 5, but the present invention is not limited to this. Instead, the magnetic bodies 22C and 22E may be provided on the surface of the substrate 22A as shown in FIG. 14 and FIG. 15. In this example, the rotor 22 has the magnetic bodies 22C (magnetic bodies 22C1 and 22C2) and the magnetic bodies 22E (magnetic bodies 22E1 and 22E2). As shown in FIG. 14, the magnetic body 22C1 is provided on the surface of the substrate 22A on the side where the magnetic core 21A1 is provided, and the magnetic body 22C2 is provided on the surface of the substrate 22A on the side where the magnetic core 21A2 is provided. In this example, the magnetic bodies 22C1 and 22C2 have a ring shape. One end and the other end of the winding 22B are connected to the rectifier circuit 14 via the pattern wiring inside the substrate 22A, for example, at the portion 22D1. The magnetic body 22E1 is provided on the surface of the substrate 22A on the side on which the magnetic core 21A1 is provided, and the magnetic body 22E2 is provided on the surface of the substrate 22A on the side on which the magnetic core 21A2 is provided.

16 shows an example of magnetic flux at the openings 123 and 124 of the power transmission device 20 according to this modified example. In the vicinity of the opening 123, in this example, leakage magnetic flux occurs from the magnetic core 21A2 in the direction toward the magnetic body 22C2, leakage magnetic flux occurs from the magnetic body 22C2 in the direction toward the magnetic body 22C1, and leakage magnetic flux occurs from the magnetic body 22C1 in the direction toward the magnetic core 21A1. In this way, in the vicinity of the opening 123, the magnetic core 21A1 and the magnetic core 21A2 are magnetically coupled to each other via the magnetic bodies 22C1 and 22C2. Also, in the vicinity of the opening 124, in this example, leakage magnetic flux occurs from the magnetic core 21A1 in the direction toward the magnetic body 22E1, leakage magnetic flux occurs from the magnetic body 22E1 in the direction toward the magnetic body 22E2, and leakage magnetic flux occurs from the magnetic body 22E2 in the direction toward the magnetic core 21A2. In this way, magnetic core 21A1 and magnetic core 21A2 are magnetically coupled to each other via magnetic bodies 22E1 and 22E2 near opening 124.

In the power transmission device 20 according to this modification, magnetic body 22C (magnetic bodies 22C1, 22C2) and magnetic body 22E (magnetic bodies 22E1, 22E2) are provided, so that the gap G can be made even shorter than in the above embodiment (FIG. 7), and the spread of leakage magnetic flux in the radial direction (horizontal direction in FIG. 16) can be further suppressed. This further reduces the possibility of leakage magnetic flux entering the shaft 24 or winding 22B, thereby reducing energy loss and improving the efficiency of the motor.

In this example, the radial width (horizontal direction in FIG. 14) of the magnetic bodies 22C1 and 22C2 is the same as the width of the convex portion near the opening 123 of the two convex portions on both sides of the recess 121 in the radial direction of the magnetic core 21A2, but this is not limited to this. Instead, for example, as shown in FIG. 17, the radial width (horizontal direction in FIG. 17) of the magnetic bodies 22C1 and 22C2 may be wider than the width of the convex portion near the opening 123 of the two convex portions on both sides of the recess 121 in the radial direction of the magnetic core 21A2.

Similarly, the radial width (horizontal direction in FIG. 14) of the magnetic bodies 22E1, 22E2 is the same as the width of the convex portion near the opening 124 of the two convex portions on both sides of the recess 121 in the radial direction of the magnetic core 21A2, but is not limited to this. Instead, for example, as shown in FIG. 17, the radial width (horizontal direction in FIG. 17) of the magnetic bodies 22E1, 22E2 may be wider than the width of the convex portion near the opening 124 of the two convex portions on both sides of the recess 121 in the radial direction of the magnetic core 21A2.

[Modification 6]
In the above embodiment, the magnetic bodies 22C and 22E are fitted into the cutouts in the substrate 22A as shown in FIG. 5, but the present invention is not limited to this. Instead, the magnetic bodies 22C and 22E may be embedded in the substrate 22A as shown in FIG. 18 and FIG. 19. In this example, the magnetic bodies 22C and 22E have a ring shape. The magnetic body 22C is provided in the substrate 22A at a portion of the substrate 22A corresponding to the opening 123. One end and the other end of the winding 22B are connected to the rectifier circuit 14 via the pattern wiring on the surface of the substrate 22A in which the magnetic body 22C is embedded, for example, at the portion 22D2. The magnetic body 22E is provided in the substrate 22A at a portion of the substrate 22A corresponding to the opening 124.

In this example, the radial width (horizontal direction in FIG. 18) of magnetic body 22C is the same as the width of the convex portion near opening 123 of the two convex portions on both sides of recess 121 in the radial direction of magnetic core 21A2, but this is not limited to this. Instead, for example, as shown in FIG. 20, the radial width (horizontal direction in FIG. 20) of magnetic body 22C may be wider than the width of the convex portion near opening 123 of the two convex portions on both sides of recess 121 in the radial direction of magnetic core 21A2.

Similarly, the radial width (horizontal direction in FIG. 18) of magnetic body 22E is the same as the width of the convex portion near opening 124 of the two convex portions on both sides of recess 121 in the radial direction of magnetic core 21A2, but is not limited to this. Instead, for example, as shown in FIG. 20, the radial width (horizontal direction in FIG. 20) of magnetic body 22E may be wider than the width of the convex portion near opening 124 of the two convex portions on both sides of recess 121 in the radial direction of magnetic core 21A2.

[Modification 7]
In the above embodiment, the magnetic body 22C is provided only at the position corresponding to the opening 123 as shown in FIG. 3, but the present invention is not limited thereto. Instead, the magnetic body 22C may be provided in the region of the substrate 22A that includes the portion corresponding to the opening 123 of the magnetic core 21A and the portion outside the portion in the XY plane as shown in FIG. 21 and FIG. 22. In this example, the present modification is applied to the power transmission device 20 (FIGS. 12 and 13) according to the modification 4. The magnetic body 22C is embedded in the substrate 22A. In this 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, a gap G is provided between the outer end of the magnetic body 22C and the magnetic core 21A2 in the radial direction (horizontal direction in FIG. 21).

23 shows a cross-sectional view of the stator 21 and rotor 22 in the power transmission device 20 according to this modified example. 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 protrusions near the opening 123 of the magnetic body 22C and the magnetic core 21A2 are magnetically coupled to each other. In addition, the outer end of the magnetic body 22C in the radial direction (horizontal direction in FIG. 23) and the magnetic core 21A2 are magnetically coupled to each other. As a result, in this power transmission device 20, as shown in FIG. 6, a magnetic path MP passing through the magnetic core 21A1, the magnetic body 22C, and the magnetic core 21A2, and a magnetic path MP passing through the magnetic body 22C and the magnetic core 21A2 are generated. This reduces the possibility of leakage flux near the opening 123 entering the shaft 24 or winding 22B, thereby reducing energy loss and improving the efficiency of the motor.

[Modification 8]
In the above embodiment, the rotor 22 is configured using the substrate 22A, but this is not limited thereto, and the rotor 22 can be configured using various members capable of supporting the windings 22B. This modification will be described in detail below.

Figures 24 and 25 show an example of the configuration of a power transmission device 20 according to this modification. In this example, this modification is applied to the power transmission device 20 according to modification 4 (Figures 12 and 13). This power transmission device 20 has a rotor 42. The rotor 42 has a support member 42A, a winding 42B, and a magnetic body 42C.

In this example, the support member 42A is made of resin. The support member 42A is connected to the shaft 24 and rotates about the rotation axis AZ in response to the rotation of the shaft 24. The support member 42A is provided with a groove-shaped recess 142 along the circumferential direction A (Figure 25) of the rotation axis AZ.

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

As shown in FIG. 24, the magnetic body 42C is provided at a position in the rotor 42 corresponding to the opening 123 of the stator 21. As shown in FIG. 25, the magnetic body 42C is provided so as to extend along the circumferential direction A of the rotation axis AZ. In this example, the magnetic body 42C has the shape of the letter "C". Specifically, the support member 42A has a cutout portion in the shape of the letter "C", and the magnetic body 42C is fitted into the cutout portion of the support member 42A. The part of the support member 42A that is inside the magnetic body 42C and the part that is outside the magnetic body 42C are connected by the part 42D of the support member 42A. However, this is not limited to this, and the magnetic body 42C may have a ring shape. In this case, for example, an insulating film can be provided on a part of the surface of the magnetic body 42C, and wiring that connects one end and the other end of the winding 42B to the rectifier circuit 14 can be provided on the insulating film.

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

[Modification 9]
In the above embodiment, the winding 21B is wound directly around the magnetic core 21A2 along the recess 121 of the magnetic core 21A2 as shown in Figures 3 and 4, but the present invention is not limited to this. Instead of this, for example, as shown in Figure 26, a bobbin 21C wound with the winding 21B may be disposed in the recess 121 of the magnetic core 21A2. The bobbin 21C is made of, for example, resin.

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

The present invention has been described above using embodiments and modifications, but the present invention is not limited to these embodiments and can be modified in various ways.

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

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

Furthermore, the present disclosure may take the following forms:

(1)
a magnetic core having a ring shape including a through hole through which a shaft passes, including a cavity along a circumferential direction of a rotation axis of the shaft, and a first opening provided along the circumferential direction on a first surface in contact with the through hole and connecting the through hole and the cavity;
a first winding provided in the cavity and wound along the circumferential direction;
a rotating member provided at a position corresponding to the first opening in the axial direction of the rotating shaft, the rotating member being rotatable in the circumferential direction within the cavity in response to rotation of the shaft;
a second winding provided on the rotating member and wound in the circumferential direction;
a first magnetic body provided along the circumferential direction in a portion of the rotating member corresponding to the first opening of the magnetic core.
(2)
the rotating member has a notch extending in the circumferential direction at a portion corresponding to the first opening of the magnetic core,
The power transfer device according to (1), wherein the first magnetic body is provided in the cutout portion of the rotating member.
(3)
The power transfer device according to (1), wherein the first magnetic body is provided on a surface of a portion of the rotating member that corresponds to the first opening of the magnetic core.
(4)
The power transfer device according to (1), wherein the first magnetic body is provided inside the rotating member 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 inside the rotating member in a region including a portion of the rotating member corresponding to the first opening of the magnetic core and a portion in which the second winding is provided, within a plane in the rotating member that intersects with the rotation axis.
(6)
Further comprising a second magnetic body,
the magnetic core has a second opening provided in a second surface opposite to the first surface in a radial direction of the rotation shaft, the second opening being located at a position corresponding to the first opening in the axial direction;
The power transmission device according to any one of (1) to (4), wherein the second magnetic body is provided along the circumferential direction in a portion of the rotating member corresponding to the second opening of the magnetic core.
(7)
a motor having a motor stator including a first motor magnetic core and a first motor winding, and a motor rotor including a second motor magnetic core and a second motor winding;
a shaft connected to the motor rotor;
An inverter;
a magnetic core having a ring shape including a through hole through which the shaft passes, including a cavity along a circumferential direction of the shaft, and a first opening provided along the circumferential direction on a first surface in contact with the through hole, the first opening connecting the through hole and the cavity;
a first winding connected to the inverter, provided in the cavity, and wound in the circumferential direction;
a rotating member provided at a position corresponding to the first opening in the axial direction of the shaft, the rotating member being rotatable in the circumferential direction within the cavity in response to rotation of the shaft;
a second winding provided on the rotating member and wound in the circumferential direction;
a first magnetic body provided along the circumferential direction in a portion of the rotating member corresponding to the first opening of the magnetic core;
a rectifier circuit provided in a path connecting the second winding and the second motor winding.

Claims (7)

a magnetic core having a ring shape including a through hole through which a shaft passes, including a cavity along a circumferential direction of a rotation axis of the shaft, and a first opening provided along the circumferential direction on a first surface in contact with the through hole and connecting the through hole and the cavity;
a first winding provided in the cavity and wound along the circumferential direction;
a rotating member provided at a position corresponding to the first opening in the axial direction of the rotating shaft, the rotating member being rotatable in the circumferential direction within the cavity in response to rotation of the shaft;
a second winding provided on the rotating member and wound in the circumferential direction;
a first magnetic body provided along the circumferential direction in a portion of the rotating member corresponding to the first opening of the magnetic core. the rotating member has a notch extending in the circumferential direction at a portion corresponding to the first opening of the magnetic core,
The power transfer device according to claim 1 , wherein the first magnetic body is provided in the cutout portion of the rotating member. The power transfer device according to claim 1 , wherein the first magnetic body is provided on a surface of the rotating member at a portion corresponding to the first opening of the magnetic core. The power transfer device according to claim 1 , wherein the first magnetic body is provided inside the rotating member at a portion of the rotating member that corresponds to the first opening of the magnetic core. The power transmission device of claim 1, wherein the first magnetic body is provided inside the rotating member in a region of the rotating member that includes a portion of the rotating member that corresponds to the first opening of the magnetic core and a portion in which the second winding is provided, within a plane of the rotating member that intersects with the rotation axis. Further comprising a second magnetic body,
the magnetic core has a second opening provided in a second surface opposite to the first surface in a radial direction of the rotation shaft, the second opening being located at a position corresponding to the first opening in the axial direction;
The power transfer device according to claim 1 , wherein the second magnetic body is provided along the circumferential direction in a portion of the rotating member that corresponds to the second opening of the magnetic core. a motor having a motor stator including a first motor magnetic core and a first motor winding, and a motor rotor including a second motor magnetic core and a second motor winding;
a shaft connected to the motor rotor;
An inverter;
a magnetic core having a ring shape including a through hole through which the shaft passes, including a cavity along a circumferential direction of the shaft, and a first opening provided along the circumferential direction on a first surface in contact with the through hole, connecting the through hole and the cavity;
a first winding connected to the inverter, provided in the cavity, and wound in the circumferential direction;
a rotating member provided at a position corresponding to the first opening in the axial direction of the shaft, the rotating member being rotatable in the circumferential direction within the cavity in response to rotation of the shaft;
a second winding provided on the rotating member and wound in the circumferential direction;
a first magnetic body provided along the circumferential direction in a portion of the rotating member corresponding to the first opening of the magnetic core;
a rectifier circuit provided in a path connecting the second winding and the second motor winding.

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