Non-contact power supply coil unit, non-contact power transmission device, and non-contact power supply device

Abstract

Provided is a coil unit (100) comprising a plurality of coil rings (110) provided with at least two or more coils (111) that are installed on a rotating body (1) which performs a rotating motion about a rotation axis, and that are formed on a plane intersecting the rotation axis of the rotating body (1) to form a loop that does not include the rotation axis, the coil rings being configured so as to surround the periphery of the rotating body (1) in the rotation direction with the coils (111). The coil unit is configured by stacking and connecting the plurality of coil rings (110) in the rotation axis direction of the rotating body (1). Each of the coil rings (110) has a facing part in which the coil winding is interrupted so that the coils face each other in the rotation direction when viewed from the rotation axis direction of the rotating body (1). When the coil unit (100) is viewed from the rotation axis direction, the facing parts of the plurality of coil rings (110) do not overlap each other.

Description

Contactless power supply coil unit, contactless power transmission device, and contactless power supply device

[0001] The present disclosure relates to a contactless power supply coil unit, a contactless power transmitting device, and a contactless power supply device.

[0002] There is a contactless power supply technology that uses magnetic field coupling to transmit power contactlessly by magnetically coupling two coils separated by a space. Because it is possible to supply power even when the power transmitting and receiving sides are physically separated, it is expected to be applied to moving objects. One possible application is to install it in an electric motor that rotates around an axis, where it can be used as a means of transmitting power while in rotational motion. Slip rings are used as a means of supplying power to rotating objects, but they have issues such as the generation of wear powder because they have physical contact points. Because contactless power supply technology can supply power even when the power transmitting and receiving sides are physically separated, it is expected to be applied to electric motors that rotate around an axis.

[0003] A contactless power supply device has been disclosed that has a power transmitting coil and a power receiving coil that are long and loop-shaped, and the opposing windings of the power transmitting coil and the power receiving coil are arranged to surround the rotation axis of a rotating body (see, for example, Patent Document 1). Also, a power receiving device has been disclosed in which the power receiving coil has a magnetic core with a circular cross section perpendicular to the longitudinal direction, and multiple spiral coils are arranged in an annular shape to cover the entire circumferential surface of the core (see, for example, Patent Document 2).

[0004] JP 2007-208201 A JP 2019-216583 A

[0005] However, while the configuration of Patent Document 1 can be miniaturized, there are points where the coil is interrupted around the rotating body, which causes the interlinkage magnetic flux to the receiving coil to fluctuate depending on the rotation angle, resulting in fluctuations in the power supply. Also, in the configuration of Patent Document 2, multiple annular coils are arranged at staggered positions, which increases the installation area by the number of coils installed, making it difficult to miniaturize the coils.

[0006] The present disclosure discloses technology for solving the above-mentioned problems, and aims to provide a contactless power supply coil unit, a contactless power transmission device, and a contactless power supply device that can stably supply power to a rotating body and have a coil structure suitable for miniaturization.

[0007] A contactless power transfer coil unit according to the present disclosure is mounted on a rotating body that rotates about a rotation axis, and includes at least two or more coils that are formed on a plane intersecting the rotation axis of the rotating body and form a loop that does not include the rotation axis, and includes a plurality of coil rings configured to surround the periphery of the rotating body in the rotational direction with the coils, and is configured by arranging and connecting the plurality of coil rings in a stacked manner in the rotational axis direction of the rotating body, and the coil rings have opposing portions where the coil windings are discontinued in the rotational direction as viewed from the rotational axis direction of the rotating body and the coils face each other, and the opposing portions of the plurality of coil rings are arranged so that they do not overlap each other when viewed from the rotational axis direction.A contactless power transmission device according to the present disclosure includes the contactless power transfer coil unit and at least one power source for supplying a current to the coil unit, and at the opposing portions where the coils constituting the first coil ring and the second coil ring face each other in the rotational direction of the rotating body, the power source controls the directions of current flowing in the opposing coil windings to be opposite to each other. A contactless power transmission device according to the present disclosure includes the contactless power supply coil unit and at least one power source for supplying current to the coil unit, and at opposing portions where the coils constituting the first coil loop and the second coil loop face each other in the rotational direction of a rotating body, the power source controls the direction of current flowing in the opposing coil windings to be the same. The contactless power transmission device according to the present disclosure uses the contactless power supply coil unit as one or both of a power transmission coil and a power receiving coil. The contactless power transmission device according to the present disclosure includes the contactless power transmission device.

[0008] The contactless power supply coil unit of the present disclosure provides a contactless power supply coil unit that stably supplies power to a rotating body and achieves a coil structure suitable for miniaturization.The contactless power transmission device of the present disclosure provides a contactless power supply transmitter that stably supplies power to a rotating body and achieves a coil structure suitable for miniaturization.The contactless power supply device of the present disclosure provides a contactless power supply device that stably supplies power to a rotating body and achieves a coil structure suitable for miniaturization.

[0009] FIG. 5A is a diagram illustrating a configuration example of a power transmission resonant circuit and a power receiving resonant circuit according to the first embodiment. FIG. 6B is a diagram illustrating a configuration example of a coil ring according to the first embodiment. FIG. 7A is a diagram illustrating a configuration example of a power receiving device according to the first embodiment. FIG. 7B is a diagram illustrating an arrangement of a power transmission coil and a rotating body according to the first embodiment. FIG. 5A is a diagram illustrating a configuration example of a power transmission resonant circuit and a power receiving resonant circuit according to the first embodiment. FIG. 5B is a diagram illustrating a configuration example of a power transmission coil and a rotating body according to the first embodiment. FIG. 6A is a diagram illustrating a structural example of a coil ring according to the first embodiment. FIG. 6B is a diagram illustrating a structural example of a coil ring according to the first embodiment. FIG. 7B is a diagram illustrating a structural example of a coil ring according to the first embodiment. FIG. 8A is a diagram illustrating a structural example of a coil ring according to the second embodiment. FIG. 8B is a diagram illustrating a structural example of a coil ring according to the second embodiment. FIG. 9A is a diagram illustrating a structural example of a coil ring according to the second embodiment. FIG. 9B is a diagram illustrating a structural example of a coil ring according to the second embodiment. FIG. 10A is a diagram illustrating a direction of a current flowing in a power transmission coil according to the second embodiment. FIG. 10B is a diagram illustrating a direction of a current flowing in a power transmission coil according to the second embodiment. Fig. 11A is a diagram illustrating a structural example of a coil ring according to embodiment 3. Fig. 11B is a diagram illustrating a structural example of a coil ring according to embodiment 3. Fig. 12A is a diagram illustrating a structural example of a contactless power feed coil unit according to embodiment 3. Fig. 12B is a diagram illustrating a structural example of a contactless power feed coil unit according to embodiment 3. Fig. 12A is a diagram illustrating a structural example of a contactless power feed coil unit according to embodiment 3. Fig. 12B is a diagram illustrating a structural example of a different contactless power feed coil unit according to embodiment 3 and a connection method.

[0010] Embodiment 1. Embodiment 1 relates to a contactless power transfer coil unit that is installed on a rotating body that performs rotational motion around a rotation axis, and includes at least two or more coils that are formed on a plane that intersects the rotation axis of the rotating body and form a loop that does not include the rotation axis, and includes a plurality of coil rings that are configured so that the coils surround the periphery of the rotating body in the rotation direction, and is configured by arranging and connecting the plurality of coil rings in a stacked manner in the rotation axis direction of the rotating body, and the coil rings have opposing portions where the coil winding is interrupted in the rotation direction as viewed from the rotation axis direction of the rotating body and the coils face each other, and is arranged so that the opposing portions of the plurality of coil rings do not overlap each other when the coil unit is viewed from the rotation axis direction.

[0011] The contactless power transfer coil unit according to embodiment 1 will be described with reference to Fig. 1 which is a diagram illustrating the configuration of a contactless power transfer device, Fig. 2 which is a diagram illustrating configuration examples of a power transmitting resonant circuit and a power receiving resonant circuit, Fig. 3 which is a diagram illustrating a configuration example of a power receiving device, Fig. 4 which is a diagram illustrating the arrangement of a contactless power transfer coil and a rotating body, Figs. 5A and 5B which are diagrams illustrating configuration examples of a contactless power transfer coil, Figs. 6A and 6B which are diagrams illustrating configuration examples of a coil ring, and Fig. 7 which is a diagram illustrating a configuration example of a contactless power transfer coil unit. Note that the same or corresponding parts in each diagram are designated by the same reference numerals.

[0012] First, the configuration and function of the contactless power supply device of the first embodiment, and configuration examples of the power supply, the power transmitting resonant circuit, the power receiving resonant circuit, and the power receiving circuit, which are the main components of the contactless power supply device, will be described with reference to Fig. 1 to Fig. 3. Note that a device configured from the power supply, the power transmitting resonant circuit, the power receiving resonant circuit, and the power receiving circuit is referred to as a contactless power supply device 1000.

[0013] First, the configuration and functions of a contactless power transfer device 1000 will be described with reference to FIG. 1 . The contactless power transfer device 1000 shown in FIG. 1 is composed of an AC power source 10, a power transmitting resonant circuit 20, a power receiving resonant circuit 30, and a power receiving circuit 40. Power is supplied from the AC power source 10, and the power transmitting resonant circuit 20 converts electrical energy into magnetic energy. The power receiving resonant circuit 30 receives the magnetic energy and converts it into AC electrical energy, and the transmitted energy is utilized by the power receiving circuit 40. The AC power source 10 is a power source that outputs a high-frequency voltage or current. The AC power source 10 may include a power converter such as an inverter and a DC / DC converter, and the output voltage waveform and current waveform may be waveforms containing multiple frequency components, such as rectangular waves. Note that in FIG. 1 , a device composed of the AC power source 10 and the power transmitting coil 21 shown in FIG. 2 , which will be described later, is referred to as a contactless power transfer device 50.

[0014] FIG. 2 shows exemplary configurations of the power transmitter resonant circuit 20 and the power receiver resonant circuit 30. The power transmitter resonant circuit 20 is composed of a power transmitter coil 21 and at least one power transmitter-side resonant capacitor 22. The power transmitter resonant circuit 20 may be configured to include a resonant coil other than the power transmitter coil 21 and a resonant capacitor other than the power transmitter-side resonant capacitor 22. The power transmitter coil 21 and the power transmitter-side resonant capacitor 22 are designed to achieve a resonant condition at or near the output frequency of the AC power source 10. When the output waveform of the AC power source 10 is a waveform containing harmonic components, such as a rectangular wave, the power transmitter resonant circuit 20 is generally designed to satisfy the resonant condition for the fundamental component of the output waveform. However, it may also be designed to resonate with respect to the harmonic components. Note that the power transmitter resonant circuit 20 shown in FIG. 2 illustrates one applicable resonant circuit configuration and does not limit the configuration of the power transmitter resonant circuit 20.

[0015] The power receiving resonant circuit 30 is composed of a power receiving coil 31 and at least one power receiving-side resonant capacitor 32. The power receiving resonant circuit 30 may be configured to include a resonant coil other than the power receiving coil 31 and a resonant capacitor other than the power receiving-side resonant capacitor 32. The power receiving coil 31 and the power receiving-side resonant capacitor 32 are designed to achieve a resonant condition at the output frequency of the AC power source 10 or near the output frequency. When the output waveform of the AC power source 10 is a waveform containing harmonic components, such as a rectangular wave, the power receiving resonant circuit 30 is generally designed to satisfy the resonant condition for the fundamental component of the output waveform, but it may also be designed to resonate with the harmonic components. Note that the power receiving resonant circuit 30 shown in FIG. 2 is configured with one resonant capacitor 32 connected in series to the power receiving coil 31, but this is merely an example of one applicable resonant circuit configuration and does not limit the configuration of the power receiving resonant circuit 30.

[0016] FIG. 3 illustrates a specific example configuration of the power receiving circuit 40. The power receiving circuit 40 shown in FIG. 3 is composed of a rectifier circuit 41, a filter 42, and a load 43. The rectifier circuit 41 is a full-bridge diode rectifier circuit that converts AC power to DC power. The filter 42 attenuates high-frequency AC components contained in the output of the rectifier circuit 41. The load 43 is an electrical device that consumes DC power and a battery that stores the power, and may include a power conversion circuit such as a voltage stabilization circuit. The configuration of the power receiving circuit 40 shown in FIG. 3 is merely an example, and each element may be omitted or modified. For example, the rectifier circuit 41 may be omitted and AC power may be consumed directly, or the filter 42 may be omitted and DC power containing AC components may be consumed. Furthermore, the rectifier circuit 41 and the filter 42 may be replaced with a different circuit configuration or with equivalent functions.

[0017] FIG. 4 shows the arrangement of the rotating body 1 and the contactless power transfer coil in the first embodiment. The rotating body 1 rotates around a rotation axis 1J indicated by a dotted line. The power transmission coil 21 and the power receiving coil 31 of the contactless power transfer device 1000 in the first embodiment are arranged to surround the periphery of the rotating body 1 and are arranged on a plane intersecting the rotation axis 1J, and the planes on which the power transmission coil 21 and the power receiving coil 31 are arranged are different from each other. During contactless power transfer, the power transmission coil 21 generates magnetic flux in the direction of the rotation axis, and the power receiving coil 31 receives this magnetic flux and generates an electromotive force. By aligning the main direction of magnetic flux generation in the direction of the rotation axis, it is possible to suppress magnetic flux linkage to the rotation axis 1J and prevent losses due to eddy current loss. As a result, metal can be used for the rotating body 1, improving design flexibility. The contactless power transfer device 1000 also includes an AC power source 10 and a power receiving circuit 40, but their arrangement is not particularly limited and they may be installed near the rotating body 1. Alternatively, wiring may be routed from the power transmission coil 21 and the power receiving coil 31 and disposed at a distance from the rotating body 1 .

[0018] 5A and 5B show an example structure of the coil ring 110, which is a component of the contactless power transfer coil unit according to the first embodiment. FIG. 5A shows the coil ring 110 as seen from the direction of the rotation axis of the rotating body 1, and FIG. 5B shows the coil ring 110 as seen from the side of the rotating body 1. While the winding is illustrated in a simplified form in FIG. 5B, the coil ring 110 has the same structure as the coil ring 110 in FIG. 5A. The coil ring 110 in FIG. 5A is composed of only a two-turn coil 111, forming an elongated coil that extends in the direction of rotation so as to surround the periphery of the rotating body 1. That is, the rotating body 1 is located inside the ring formed by the outer shape of the coil ring 110. Meanwhile, the rotating body 1 is located outside the elongated loop coil formed by the coil 111. In this way, the coil ring 110 surrounds the rotating body 1 with its outer shape, and the rotating body 1 is located outside the loop formed by the coil winding. Furthermore, because the coil ring 110 has a structure that surrounds the rotating body 1, the ends of the coils are arranged to face each other in the direction of rotation. Hereinafter, the location where the ends of the coil windings face each other will be referred to as the "facing portion." In Figure 7, this is referred to as facing portion AD.

[0019] 6A and 6B show a structural example of a contactless power transfer coil unit 100 according to the first embodiment. The contactless power transfer coil unit will be referred to as a coil unit where appropriate. FIG. 6A shows the coil unit 100 as viewed from the direction of the rotation axis of the rotating body 1, and FIG. 6B shows the coil unit 100 as viewed from the side of the rotating body 1. The coil unit 100 in FIG. 6A is composed of a first coil ring 110F and a second coil ring 120S, with the first coil ring 110F being composed of a coil 111 and the second coil ring 120S being composed of a coil 121. While the windings of the coil unit 100 are shown in a simplified form in FIG. 6B, the coil unit 100 has the same structure as the coil unit 100 in FIG. 6A. Both the first coil ring 110F and the second coil ring 120S have the same structure as the coil rings described in Figures 5A and 5B, and the first coil ring 110F and the second coil ring 120S extend in the rotational direction of the rotating body 1 to surround the rotating body 1, and are structured so that the rotating body 1 is located outside the loop formed by the coil winding.

[0020] The first coil ring 110F and the second coil ring 120S are stacked with a gap L in the direction of the rotation axis of the rotating body 1. When stacked, the facing portions AD of the first coil ring 110F and the second coil ring 120S are arranged so that they do not overlap when viewed from the direction of the rotation axis of the rotating body 1. One effect of arranging the facing portions AD of each coil ring in this manner is that fluctuations in the generated magnetic flux can be suppressed during rotation. The facing portions AD are where the winding is interrupted in the direction of rotation of the rotating body 1, and therefore are areas where the generated magnetic flux decreases, but the coil rings complement each other, suppressing the decrease in magnetic flux at the facing portions AD.

[0021] More preferably, as shown in Figures 6A and 6B, the facing portion AD of the first coil ring 110F is positioned so that the distance from one end of the coil of the second coil ring 120S in the direction of rotation of the rotor 1 is equal to the distance from the other end. In this case, the facing portion AD of the second coil ring 120S is positioned so that the distance from one end of the coil of the first coil ring 110F in the direction of rotation of the rotor 1 is equal to the distance from the other end. With this arrangement, when the coil unit 100 is viewed from the direction of the rotation axis of the rotor 1, the positional relationship of the facing portions AD of each coil ring is symmetrical about the rotation axis of the rotor 1. As a result, fluctuations in the generated magnetic flux can be made regular during rotation of the rotor 1, making it easier to take measures to suppress the fluctuations.

[0022] It is preferable that the distance L between the first coil ring 110F and the second coil ring 120S in the direction of the rotation axis of the rotor 1 is small. For example, the distance L is arranged so as to be smaller than the radius of the first coil ring 110F and the second coil ring 120S centered on the rotation axis of the rotor 1, or the distance M from the center of the first coil ring 110F and the second coil ring 120S to the outermost position. By making the distance L small, the volume of the coil unit 100 becomes equivalent to the volume of the coil ring alone, and fluctuations in magnetic flux can be suppressed without requiring a large increase in size.

[0023] FIG. 7 shows an example of coil arrangement in a contactless power supply device 1000 using the coil unit according to the first embodiment. In the configuration of FIG. 7 , contactless power supply coil unit 100 and contactless power supply coil unit 200 are arranged with a distance D in the direction of the rotation axis of rotating body 1. Coil unit 100 is composed of a first coil ring 110F and a second coil ring 120S, with first coil ring 110F being composed of coil 111 and second coil ring 120S being composed of coil 121. Coil unit 200 is composed of a first coil ring 210F and a second coil ring 220S, with first coil ring 210F being composed of coil 211 and second coil ring 220S being composed of coil 221. Although the windings of coil units 100 and 200 are illustrated in a simplified manner in FIG. 7 , they have the same structure as coil unit 100 in FIG. 6A . In FIG. 7, one of the coil units functions as a power transmitting coil unit, and the other functions as a power receiving coil unit.

[0024] Here, the coil unit 100 will be described as a power transmission coil unit. In power supply, a current is passed through the first coil ring 110F and the second coil ring 120S that constitute the power transmission coil unit to generate magnetic flux. The direction of the current passed through the first coil ring 110F and the second coil ring 120S is set so that magnetic flux is generated in the same direction inside the loop formed by the windings of each coil ring. In FIG. 7 , the terminals of the first coil ring 110F and the second coil ring 120S are not connected, but in reality, a power source, a power transmission circuit, etc. are connected to pass current through them. In this case, the first coil ring 110F and the second coil ring 120S may be connected in series by connecting one of their respective terminals, or they may be connected in parallel to a circuit for passing current.

[0025] In order to suppress biased winding loss and reactive power, it is preferable to make the amplitude and phase of the current flowing through the first coil ring 110F and the second coil ring 120S the same. The power receiving coil unit, coil unit 200, is composed of a first coil ring 210F and a second coil ring 220S and outputs power by receiving magnetic flux generated by coil unit 100. As with the power transmitting coil unit, the terminals of the first coil ring 210F and the second coil ring 220S may be connected in series by connecting one terminal each, or may be connected in parallel to a power receiving circuit. However, in a series connection, care must be taken with the connection direction because the electromotive forces of the first coil ring 210F and the second coil ring 220S may cancel each other out. In the example shown in FIG. 7 , coil units according to the first embodiment are used on both the power transmitting side and the power receiving side. However, the effect of suppressing magnetic flux fluctuations during rotation can also be achieved by using a coil unit according to the first embodiment on either side.

[0026] Here, the correspondence between Fig. 7 and Fig. 2 will be explained. The power transmitting coil unit (coil unit 100) in Fig. 7 corresponds to the power transmitting coil 21 in Fig. 2. The power receiving coil unit (coil unit 200) in Fig. 7 corresponds to the power receiving coil 31 in Fig. 2. In many cases, the power transmitting coil 21 corresponding to the power transmitting coil unit and the AC power supply 10 are stationary. Note that the same effect can be obtained even if the power transmitting coil unit side is rotating.

[0027] As described above, the contactless power transfer coil unit according to the first embodiment provides contactless power transfer using magnetic flux generated in the direction of the rotation axis of a rotating body. The coil unit includes a plurality of coil rings each formed by a coil that surrounds the periphery of the rotating body in the direction of rotation, and the plurality of coil rings are connected in a stacked manner in the direction of the rotation axis of the rotating body. When viewed from the direction of the rotation axis of the rotating body, the coil rings have opposing portions where the coil winding is interrupted in the direction of rotation and the coils face each other. The opposing portions of the coil rings are arranged so that they do not overlap each other when viewed from the direction of the rotation axis. This allows for suppression of fluctuations in the magnetic flux generated by the coil unit. Furthermore, by arranging the plurality of coil rings facing each other in the direction of the rotation axis of the rotating body, magnetic flux fluctuations can be suppressed while avoiding a significant increase in size.

[0028] The above description is based on the minimum number of components, and countless variations not illustrated are conceivable within the scope of the technology disclosed in this specification. For example, a magnetic material may be disposed to strengthen magnetic coupling, or the circular portion of the coil may be changed to a polygonal shape depending on the processing method.

[0029] A contactless power transmission device can be configured by combining a power supply with the contactless power supply coil unit described in the first embodiment. Also, a contactless power supply device can be configured that uses the contactless power supply coil unit described in the first embodiment as one or both of a power transmission coil and a power receiving coil. Furthermore, a contactless power supply device can be configured that includes the above-mentioned contactless power transmission device.

[0030] As described above, the contactless power supply coil unit of the first embodiment can supply stable power to a rotating body and can realize a coil structure suitable for miniaturization.

[0031] Second Embodiment The second embodiment relates to a contactless power transfer coil unit that employs a split coil.

[0032] The contactless power transfer coil unit of embodiment 2 will be described with reference to Figures 8A, 8B, 9A, and 9B, which are diagrams illustrating examples of the structure of a coil ring, and Figures 10A and 10B, which are diagrams illustrating the direction of current flowing in the contactless power transfer coil. In the drawings of embodiment 2, parts that are the same as or equivalent to those of embodiment 1 are given the same reference numerals.

[0033] The difference from the first embodiment is that a split coil is used for the coil ring of the contactless power feeding coil unit.

[0034] 8A and 8B show an example of the structure of a coil ring 310, which is a component of the contactless power transfer coil according to the second embodiment. FIG. 8A shows the coil ring 310 as seen from the direction of the rotation axis of the rotating body 1, and FIG. 8B shows the coil ring 310 as seen from the side of the rotating body 1. While the winding is simplified in FIG. 8B, it has the same structure as the coil ring 310 in FIG. 8A. The coil ring 310 in FIGS. 8A and 8B is composed of four split coils 311, 312, 313, and 314, each of which is a two-turn coil with the same structure. The split coils 311 to 314 extend in the rotation direction so as to surround the periphery of the rotating body 1. Each split coil is formed so as to surround one-quarter of the rotating body 1, and the four split coils 311 to 314 are arranged so as to surround the entire periphery of the rotating body 1. That is, the rotating body 1 is located inside the ring formed by the outer shape of the coil ring 310, and is located outside the loop coil formed by the divided coils 311 to 314.

[0035] The coil in embodiment 1 has a doughnut shape with a hole extending in the direction of rotation, which makes it difficult to manufacture. On the other hand, the coil ring 310 in embodiment 2 is configured so that the rotor 1 is surrounded by multiple divided coils, and the individual coils are small in size, making it easy to manufacture. Increasing the number of divisions, for example to four, as shown in FIGS. 8A and 8B allows for easy shaping by applying pressure after winding the coil winding. Furthermore, since all divided coils have the same structure, mass production is easy. While FIGS. 8A and 8B show a coil divided into four, the number of divisions may be increased or decreased. However, from a manufacturing perspective, it is preferable for the number of divisions to be four or more.

[0036] In the contactless power transfer coil unit of the first embodiment, the coil ring is made up of a single coil, and the portion of the single coil where the ends of the coil face each other in the direction of rotation of the rotating body is defined as the "facing portion." In the case of the divided coils 311 to 314 that make up the coil ring 310 of the second embodiment, each divided coil faces a different divided coil at its end in the direction of rotation of the rotating body 1. Therefore, in the coil ring 310 of the second embodiment, the portion where different divided coils face each other is defined as the "facing portion." The number of these facing portions AD varies depending on the structure of the coil ring 310; for example, the coil ring 310 in FIGS. 8A and 8B has four facing portions AD.

[0037] 9A and 9B show an example of the structure of a contactless power transfer coil unit 300 according to the second embodiment. Fig. 9A shows the coil unit 300 as seen from the direction of the rotation axis of the rotating body 1, and Fig. 9B shows the coil unit 300 as seen from the side of the rotating body 1. Although Fig. 9B shows a simplified illustration of the windings of the coil unit 300, it has the same structure as the coil unit 300 in Fig. 9A.

[0038] The coil unit 300 in Figures 9A and 9B is composed of a first coil ring 310F and a second coil ring 320S. The first coil ring 310F is composed of split coils 311 to 314, and the second coil ring 320S is composed of split coils 321, 322, 323, and 324. Both the first coil ring 310F and the second coil ring 320S have the same structure as the coil rings described in Figures 8A and 8B. The first coil ring 310F and the second coil ring 320S extend in the rotational direction of the rotor 1 and surround the rotor 1, with the rotor 1 positioned outside the loop formed by the coil winding. Note that the opposing portion AD is omitted in Figures 9A and 9B for clarity.

[0039] The first coil ring 310F and the second coil ring 320S are stacked with a gap L in the direction of the rotation axis of the rotating body 1. When stacked, the facing portions AD of the first coil ring 310F and the second coil ring 320S are arranged so that they do not overlap when viewed from the direction of the rotation axis of the rotating body 1. By arranging the facing portions AD of each coil ring in this manner, it is possible to suppress a decrease in the generated magnetic flux. The facing portions AD are places where the winding is interrupted in the direction of rotation of the rotating body 1, so the generated magnetic flux decreases, but the coil rings complement each other, suppressing fluctuations due to the decrease in magnetic flux.

[0040] 9A and 9B, it is preferable to arrange the first coil ring 310F and the second coil ring 320S so that their opposing portions AD are equally spaced in the direction of the rotation axis of the rotating body 1. In Figures 9A and 9B, the second coil ring 320S is rotated 45 degrees in the rotation direction of the rotating body 1 relative to the first coil ring 310F and overlapped therewith, so that all of the opposing portions AD are equally spaced. By arranging the coils in this way, it is possible to regularize the fluctuations in the generated magnetic flux during rotation of the rotating body 1, making it easier to take measures to suppress the fluctuations.

[0041] The distance L between the first coil ring 310F and the second coil ring 320S in the direction of the rotation axis of the rotor 1 is preferably small, and is arranged so as to be smaller, for example, than the radius of the first coil ring 310F and the second coil ring 320S centered on the rotation axis of the rotor 1, or the distance M from the center of the first coil ring 310F and the second coil ring 320S to the outermost position. By making the distance L small, it is possible to suppress fluctuations in magnetic flux without substantially increasing the volume of the coil unit 300.

[0042] 10A and 10B show the direction of current flowing in the contactless power transfer coil unit 300 according to the second embodiment. There are two different current directions, each of which has a different effect. In FIG. 10A, the currents flowing in the two coil windings in the opposing portion AD are set in opposite directions. In the current direction shown in FIG. 10A, the magnetic fluxes generated by the windings in the opposing portion AD that extend radially relative to the rotation axis of the rotating body 1 cancel each other out. Therefore, the magnetic fluxes penetrating the interior of each coil are oriented in the same direction. As a result, magnetic flux can be generated uniformly from the entire coil, resulting in strong magnetic coupling.

[0043] In Figure 10B, the currents flowing through the two coil windings in the opposing portion AD are set to the same direction. Therefore, the number of coil divisions must necessarily be an even number. With the current direction shown in Figure 10B, the direction of the magnetic flux generated perpendicular to the imaginary plane on which the coils are arranged varies depending on the position of the coil loop, and the magnetic flux alternates with the direction of rotation of the rotor 1. As a result, the main direction of magnetic flux is perpendicular to the imaginary plane on which the coils are arranged and in the direction of rotation of the rotor 1, thereby reducing the impact on the inner and outer directions of the coil loop's outer shape. This prevents interference with peripheral devices and loss due to electromagnetic induction. This reduces the need for anti-fault components such as aluminum shields, thereby reducing costs.

[0044] 10B, by setting the phase difference between the current flowing through the split coils 311 to 314 constituting the first coil ring 310F and the current flowing through the split coils 321 to 324 constituting the second coil ring 320S to a quarter cycle, it is possible to eliminate the section in the drive cycle of the contactless power supply device where the output becomes zero, thereby achieving the effect of stabilizing the output voltage.

[0045] As described above, the contactless power transfer coil unit according to the second embodiment transfers power contactlessly using magnetic flux generated in the direction of the rotation axis of a rotating body, and includes a plurality of coil rings each made up of a plurality of split coils that surround the periphery of the rotating body in the direction of rotation, with the plurality of coil rings connected in a stacked manner in the direction of the rotation axis of the rotating body. When viewed from the direction of the rotation axis of the rotating body, the coil rings have opposing portions where the coil winding is interrupted and the coils face each other, and the coil rings are arranged so that the opposing portions do not overlap each other when viewed from the direction of the rotation axis. Therefore, in addition to the effects of the first embodiment, by using split coils for the coil rings, manufacturing efficiency can be improved.

[0046] The contactless power feeding coil unit according to the second embodiment described above can be applied to the contactless power transmitting device and the contactless power feeding device described in the first embodiment.

[0047] As described above, the contactless power supply coil unit of the second embodiment can stably supply power to a rotating body and can realize a coil structure suitable for miniaturization. Furthermore, the use of a split coil can improve manufacturing efficiency.

[0048] Third Embodiment The third embodiment relates to a contactless power transfer coil unit having a coil in which one terminal is drawn out from a position halfway along the entire length of the coil in the direction of rotation of the rotating body.

[0049] The contactless power transfer coil unit of embodiment 3 will be described, focusing on the differences from embodiment 1, with reference to Figures 11A and 11B which are diagrams illustrating an example of the structure of a coil ring, Figures 12A and 12B which are diagrams illustrating an example of the structure of a contactless power transfer coil unit, and Figure 13 which is a diagram illustrating an example of the structure of a coil unit and a connection method. In the drawings of embodiment 3, parts that are the same as or equivalent to those of embodiment 1 are given the same reference numerals.

[0050] 11A and 11B show structural examples of a coil ring that is a component of a contactless power transfer coil unit according to the present embodiment 3. Fig. 11A shows a structural example of a coil ring 410 that is formed by a single coil, and Fig. 11B shows a structural example of a coil ring 510 that is formed by a divided coil.

[0051] A major feature of the third embodiment is the terminal lead-out position. In the coils constituting the coil ring of the third embodiment, when the length of the coil is defined in the rotation direction of the rotor 1, one terminal is led out from the end of the coil, and the other terminal is led out from a position halfway along the length of the coil. In the coil ring 410 composed of a single coil 411 shown in FIG. 11A, the terminal 411a is led out from the end of the coil 411 in the rotation direction of the rotor 1, and the terminal 411b is led out from a position halfway along the entire length of the coil 411 in the rotation direction. In the coil ring 510 composed of the split coils 511, 512, 513, and 514 shown in FIG. 11B, the terminals are led out in the same manner from all of the split coils 511 to 514. 11B as an example, terminal 511a of split coil 511 is drawn out from the end of split coil 511 in the rotational direction of rotor 1, and terminal 511b is drawn out from a position halfway along the entire length of split coil 511 in the rotational direction. As can be seen by comparing Fig. 11A and Fig. 11B, the position from which the terminals are drawn out varies depending on the coil shape.

[0052] In other words, when a line is drawn from the rotation axis to each terminal as viewed in the direction of the rotation axis, the angle between the two lines and the rotation axis is half the angle at which the coil surrounds the rotor 1 in the direction of rotation. In Figure 11A, one coil surrounds the rotor 1 by 360 degrees, so the angle formed by the lines connecting the two terminals to the rotation axis is 180 degrees. In Figure 11B, one coil surrounds the rotor 1 by 90 degrees, so the angle formed by the lines connecting the two terminals to the rotation axis is 45 degrees.

[0053] 12A and 12B show structural examples of a contactless power transfer coil unit according to the third embodiment. Fig. 12A shows a structural example in which the coil ring is composed of a single coil, and has the same structure as the coil ring shown in Fig. 11A. The contactless power transfer coil unit 400 is configured by connecting a coil 411 constituting a first coil ring 410F and a coil 421 constituting a second coil ring 420S. In Fig. 12A, the coils 411 and 421 are shown offset from each other for ease of viewing, but in reality, as shown in Fig. 12B, they are arranged overlapping each other so that the center of the circle formed by the outer shape of each coil ring coincides with the rotation axis 1J of the rotating body 1.

[0054] The contactless power transfer coil unit according to the third embodiment assumes that all of the coils constituting the coil unit are connected in series. When the coil ring of the third embodiment is configured as a coil unit, the terminals of different coils face each other. Looking at FIG. 12B , it can be seen that the terminals of the coil 411 constituting the first coil ring 410F and the coil 421 constituting the second coil ring 420S are both arranged to face each other. If terminals are drawn only from the ends of the coils, the terminals of different coils are spaced apart when the coil unit is configured, and therefore, separate wiring is required to connect the coils in series. On the other hand, the coil ring of the third embodiment has a structure in which the terminals naturally face each other, making it easy to connect the coils in series.

[0055] FIG. 13 shows an example of the structure of a coil unit using split coils according to the third embodiment. FIG. 13 shows an example of the structure when the coil ring is composed of split coils, and has the same structure as the coil ring shown in FIG. 11B . The contactless power supply coil unit 500 is configured by connecting split coils 511 to 514 that constitute the first coil ring 510F and split coils 521, 522, 523, and 524 that constitute the second coil ring 520S. Focusing on split coil 521 in FIG. 13 , the connected coils are split coil 511 and split coil 514, which are connected to coils that constitute a coil ring different from split coil 521. The same applies to the other split coils; split coils 511 to 514 that constitute the first coil ring 510F are connected to split coils 521 to 524 that constitute the second coil ring 520S. Split coils 521 to 524 that constitute the second coil ring 520S are connected to split coils 511 to 514 that constitute the first coil ring 510F. In this way, even in a configuration using split coils such as the coil unit 500 according to embodiment 3, when the coil rings are stacked to form a coil unit, the terminals of each coil are arranged opposite each other, making it possible to easily connect the coils in series. At this time, the coils constituting one coil ring and the other coil ring are alternately connected, and all of the coils are connected in series.

[0056] As described above, the contactless power transfer coil unit according to the third embodiment performs contactless power transfer using magnetic flux generated in the direction of the rotation axis of a rotating body, includes a plurality of coil rings each made up of one or more coils surrounding the periphery of the rotating body in the direction of rotation, and is configured by stacking the plurality of coil rings in the direction of the rotation axis of the rotating body. One terminal of each coil is drawn out from the end of the coil in the direction of rotation of the rotating body, and the other terminal is drawn out from a position halfway along the entire length of the coil in the direction of rotation. Therefore, when the coil unit is constructed, the terminals of each coil face each other. Therefore, in addition to the effects of the first embodiment, it is possible to easily connect the coils constituting the coil ring in series. This configuration is also effective in a configuration using split coils, and the effects of the second embodiment can also be obtained.

[0057] The contactless power feeding coil unit according to the third embodiment described above can be applied to the contactless power transmitting device and the contactless power feeding device described in the first embodiment.

[0058] As described above, the contactless power supply coil unit of the third embodiment can stably supply power to a rotating body and can realize a coil structure suitable for miniaturization. Furthermore, it can facilitate the work of connecting the coils constituting the coil ring in series.

[0059] Although various exemplary embodiments and examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are anticipated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0060] Various aspects of the present disclosure are summarized below as appendices.

[0061] (Supplementary Note 1) A contactless power transfer coil unit that is installed on a rotating body that rotates about a rotation axis, the coil unit comprising: at least two or more coils that are formed on a plane intersecting the rotation axis of the rotating body and form a loop that does not include the rotation axis; a plurality of coil rings that are configured so that the coils surround the periphery of the rotating body in the rotation direction; and the plurality of coil rings are arranged and connected to overlap in the rotation axis direction of the rotating body, the coil rings have opposing portions where the coil winding is discontinued in the rotation direction as viewed from the rotation axis direction of the rotating body and the coils face each other, and the opposing portions of the plurality of coil rings are arranged so that they do not overlap each other when viewed from the rotation axis direction. (Supplementary Note 2) The contactless power transfer coil unit according to Supplementary Note 1, (Supplementary Note 3) The contactless power transfer coil unit according to Supplementary Note 2, wherein a distance between the first coil ring and the second coil ring in the rotation axis direction is shorter than a radius of the first coil ring or the second coil ring, or a distance from a center to an outermost peripheral position of the annularly arranged coil rings. (Supplementary Note 4) The contactless power transfer coil unit according to Supplementary Note 2 or Supplementary Note 3, wherein the first coil ring and the second coil ring are constituted by at least two or more divided coils. (Supplementary Note 5) The contactless power transfer coil unit according to any one of Supplementary Note 1 to Supplementary Note 4, wherein one terminal of the coil is drawn out from an end of the coil in the rotation direction of the rotating body, and the other terminal of the coil is drawn out from a position half the length of the entire length of the coil in the rotation direction. (Supplementary Note 6) The contactless power transfer coil unit according to Supplementary Note 2 or Supplementary Note 3, wherein the coils constituting the first coil ring and the coils constituting the second coil ring are connected alternately, so that all of the coils are connected in series.(Supplementary Note 7) A contactless power transmission device comprising: the contactless power supply coil unit according to Supplementary Note 4; and at least one power source for supplying current to the coil unit, wherein at the opposing portions where the coils constituting the first coil loop and the second coil loop face each other in the rotational direction of a rotating body, the power source controls the directions of current flowing in the opposing coil windings to be opposite. (Supplementary Note 8) A contactless power transmission device comprising: the contactless power supply coil unit according to Supplementary Note 4; and at least one power source for supplying current to the coil unit, wherein at the opposing portions where the coils constituting the first coil loop and the second coil loop face each other in the rotational direction of a rotating body, the power source controls the directions of current flowing in the opposing coil windings to be the same. (Supplementary Note 9) The contactless power transmission device according to Supplementary Note 8, wherein the power source sets a phase difference between the current flowing in the coil constituting the first coil loop and the current flowing in the coil constituting the second coil loop to be ¼ period. (Supplementary Note 10) The contactless power transmission device according to Supplementary Note 8 or Supplementary Note 9, wherein the number of divisions of the coil unit is an even number equal to or greater than 4. (Supplementary Note 11) A contactless power supply device, using the contactless power supply coil unit according to any one of Supplementary Notes 1 to 6 as one or both of a power transmission coil and a power receiving coil. (Supplementary Note 12) A contactless power supply device including the contactless power transmission device according to any one of Supplementary Notes 7 to 10.

[0062] REFERENCE SIGNS LIST 1 Rotating body, 1J Rotating shaft, 10 AC power source, 20 Power transmission resonance circuit, 21 Power transmission coil, 22 Power transmission side resonance capacitor, 30 Power reception resonance circuit, 31 Power reception coil, 32 Power reception side resonance capacitor, 40 Power reception circuit, 41 Rectification circuit, 42 Filter, 43 Load, 50 Non-contact power transmission device, 100, 200, 300, 400, 500 Non-contact power supply coil unit, 110, 310, 410, 510 Coil ring, 110F, 210F, 310F, 410F, 510F First coil ring, 120S, 220S, 320S, 420S, 520S Second coil ring, 111, 121, 211, 221, 411, 421 Coil, 311, 312, 313, 314, 321, 322, 323, 324, 511, 512, 513, 514, 521, 522, 523, 524 Split coil, 411a, 411b, 511a, 511b Terminal, 1000 Non-contact power supply device, AD Opposing portion.

Claims

1. A contactless power transfer coil unit that is installed on a rotating body that rotates around a rotation axis, and that comprises at least two or more coils that are formed on a plane that intersects the rotation axis of the rotating body and form a loop that does not include the rotation axis, and that comprises a plurality of coil rings that are configured so that the coils surround the periphery of the rotating body in the rotational direction, and that is configured by arranging and connecting the plurality of coil rings in a stacked manner in the rotational axis direction of the rotating body, and that the coil rings have opposing portions where the coil winding is interrupted in the rotational direction when viewed from the rotational axis direction of the rotating body and the coils face each other, and that is arranged so that the opposing portions of the plurality of coil rings do not overlap each other when viewed from the rotational axis direction.

2. A contactless power transfer coil unit as described in claim 1, which is configured by: a first coil ring configured by arranging the plurality of coils in a ring shape around the rotation axis of the rotating body on a first plane that intersects with the rotation axis of the rotating body; and a second coil ring configured by arranging the plurality of coils in a ring shape around the rotation axis on a second plane that intersects with the rotation axis of the rotating body and is different from the first plane.

3. A contactless power transfer coil unit according to claim 2, wherein the distance between the first coil ring and the second coil ring in the direction of the rotation axis is shorter than the radius of the first coil ring or the second coil ring, or the distance from the center to the outermost position of the annularly arranged coil rings.

4. The contactless power transfer coil unit according to claim 2 or 3, wherein the first coil loop and the second coil loop are configured with at least two or more split coils.

5. A contactless power transfer coil unit according to any one of claims 1 to 4, wherein one terminal of the coil is pulled out from an end of the coil in the direction of rotation of the rotating body, and the other terminal of the coil is pulled out from a position halfway along the entire length of the coil in the direction of rotation.

6. A contactless power transfer coil unit according to claim 2 or 3, wherein the coils constituting the first coil ring and the coils constituting the second coil ring are connected alternately, so that all of the coils are connected in series.

7. A contactless power transmission device comprising the contactless power supply coil unit according to claim 4, and at least one power source for supplying current to said coil unit, wherein at the opposing portions where the coils constituting said first coil loop and said second coil loop face each other in the rotational direction of the rotor, said power source controls the direction of current flowing in the opposing coil windings to be opposite to each other.

8. A contactless power transmission device comprising the contactless power supply coil unit according to claim 4, and at least one power source for supplying current to said coil unit, wherein at opposing portions where the coils constituting said first coil loop and said second coil loop face each other in the direction of rotation of the rotor, said power source controls the direction of current flowing in the opposing coil windings to be the same.

9. The contactless power transmission device according to claim 8, wherein the power supply sets a phase difference between the current flowing through the coil that constitutes the first coil loop and the current flowing through the coil that constitutes the second coil loop to 1 / 4 period.

10. The contactless power transmission device according to claim 8 or claim 9, wherein the number of divisions of the coil unit is an even number of four or more.

11. A contactless power transfer device using the contactless power transfer coil unit according to any one of claims 1 to 6 as one or both of a power transmission coil and a power receiving coil.

12. A contactless power supply device including the contactless power transmission device according to any one of claims 7 to 10.

Images