JP2019030155A - Coil unit - Google Patents

Abstract

To acquire high coupling coefficient while suppressing the generation of a leakage flux.SOLUTION: A coil unit comprises: a ferrite 22 that includes a first main surface 22a and a second main surface 22b arranged in a thickness direction, and is formed in a plate shape; and a coil 20 that is wound around the ferrite 22 so that each coil line is alternately along the first main surface 22a and the second main surface 22b. The coil 20 includes: first surface parts 24a and 25a each contacting with the first main surface 22a, and being adjacent to each other; and a second surface part 24b contacting with the second main surface 22b. A first connection part 24c connecting the first surface parts 24a and the second surface part 24b to each other has an angle inclined to the thickness direction. The second surface part 24b contacts with the second main surface 22b at a position deviated to an arrangement direction from the first surface part 24a to the first surface part 25a from the opposite position with the first surface part 25a and the ferrite 22 interposed therebetween.SELECTED DRAWING: Figure 9

Description

  The present disclosure relates to a coil unit used for non-contact power transmission.

  Conventionally, a contactless power transmission system that transmits power in a contactless manner between two coil units is known (see Patent Documents 1 to 5).

  JP-A-2006-187298 (Patent Document 6) states that a vehicle-mounted device is greatly affected by an electromagnetic field formed around the coil by making the coil positioned on the bottom surface of the vehicle into an appropriate shape. A restraining vehicle is disclosed. In particular, Patent Document 6 discloses forming a solenoid type or a circular coil as a coil shape.

JP2013-154815A JP2013-146154A JP2013-146148A JP 2013-110822 A JP 2013-126327 A JP, 2006-187298, A

  However, in a solenoid type coil, leakage magnetic flux may occur in directions other than the power transmission side (or power reception side), and the magnetic field strength around the vehicle may increase. Even if the leakage magnetic flux can be suppressed as compared with the solenoid type coil, the coupling coefficient may be smaller than that of the solenoid type coil. Therefore, further improvement is required for the shape of the coil used for non-contact power transmission to improve the coupling coefficient while suppressing the generation of leakage magnetic flux.

  This indication is made in order to solve the subject mentioned above, and the object is to provide the coil unit which can obtain a high coupling coefficient, suppressing generation of leakage magnetic flux.

  A coil unit according to an aspect of the present disclosure includes a first main surface and a second main surface arranged in a thickness direction, and a ferrite formed in a plate shape, and a coil wire includes the first main surface and the second main surface. And a coil that is wound around a ferrite so as to be alternately arranged and arranged in a spiral shape. The coil includes a first portion and a second portion that are in contact with the first main surface and are adjacent to each other, and a third portion that is in contact with the second main surface. The fourth portion connecting the first portion and the third portion has an angle that is oblique with respect to the thickness direction. The third portion is in contact with the second main surface at a position shifted in the arrangement direction from the first portion to the second portion, rather than a position facing the second portion with the ferrite interposed therebetween.

  If it does in this way, since the flow of the magnetic flux of a coil end part can be directed to the power transmission side (or power receiving side), a high coupling coefficient can be obtained, suppressing generation | occurrence | production of leakage magnetic flux.

  According to the present disclosure, it is possible to provide a coil unit that can obtain a high coupling coefficient while suppressing generation of leakage magnetic flux.

1 is a schematic diagram showing a non-contact charging system 1. FIG. 1 is a circuit diagram schematically showing a contactless charging system 1. FIG. It is a figure which shows the structural example of a solenoid type coil. It is a figure which shows an example of the magnetic flux distribution at the time of power transmission when a solenoid type coil is used as a receiving coil. It is a figure which shows the structural example of the coil comprised by arranging a circular coil. It is a figure which shows the shape of the coil seen from the thickness direction of the ferrite. It is a figure which shows an example of the magnetic flux distribution at the time of power transmission in case the coil comprised by arranging a circular coil is used as a receiving coil. It is a perspective view which shows the structural example of the coil in this Embodiment. It is a figure which shows the structural example of the coil in this Embodiment. It is a figure which shows an example of the magnetic flux distribution at the time of power transmission in case the coil in this Embodiment is used for a power receiving apparatus.

  Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a schematic diagram showing a non-contact charging system 1. FIG. 2 is a circuit diagram schematically showing the non-contact charging system 1. As shown in FIGS. 1 and 2, the non-contact charging system 1 includes two coil units. In the following description, a coil unit connected to the power source 10 out of the two coil units is referred to as a power transmission device 3, and a coil unit provided in the vehicle 2 is referred to as a power reception device 4. Vehicle 2 further includes a battery 7.

  The power receiving device 4 includes a resonator 5 and a rectifier 6 that converts AC power received by the resonator 5 into DC power and supplies the DC power to the battery 7.

  The resonator 5 is an LC resonator and includes a power receiving coil 8 and a capacitor 9 connected to the rectifier 6. The Q value of the resonator 5 is 100 or more.

  The power transmission device 3 includes a resonator 14 and a converter 11 connected to the power source 10. The converter 11 adjusts the frequency and voltage of the AC power supplied from the power supply 10 and supplies the adjusted power to the resonator 14. The resonator 14 is an LC resonator and includes a power transmission coil 12 and a capacitor 13 connected to the resonator 14. The Q value of the resonator 14 is also 100 or more. Note that the resonance frequency of the resonator 14 and the resonance frequency of the resonator 5 substantially match.

  In FIG. 1, when power is transmitted from the power transmission device 3 to the power reception device 4 in a contactless manner, the power reception coil 8 is disposed above the power transmission coil 12. The converter 11 supplies AC power of a predetermined frequency to the resonator 14, and an AC current flows through the power transmission coil 12. The frequency of the alternating current flowing through the power transmission coil 12 is, for example, the resonance frequency of the resonator 14.

  When an alternating current flows through the power transmission coil 12, a magnetic flux is formed around the power transmission coil 12. When the frequency of the alternating current supplied to the power transmission coil 12 is the resonance frequency of the resonator, the frequency of the magnetic field formed around the power transmission coil 12 is also the resonance frequency of the resonator 14.

  The magnetic flux formed around the power transmission coil 12 is emitted radially from the winding axis and the periphery thereof. Then, an induced electromotive voltage is generated in the power receiving coil 8 because the magnetic flux from the power transmitting coil 12 is linked to the power receiving coil 8. As a result, AC power is supplied from the power transmission coil 12 to the power receiving coil 8 by the alternating current flowing through the power receiving coil 8. When an alternating current flows through the power receiving coil 8, a magnetic flux is formed around the power receiving coil 8.

  Next, the configuration of the power receiving coil 8 will be described. As the power receiving coil 8, various coil shapes can be applied. Examples of various coil shapes include a solenoid type coil and a coil having a configuration in which a plurality of circular coils are arranged. In the following description, for example, a case where a solenoid type coil is applied as the power receiving coil 8 will be described with reference to FIG.

  FIG. 3 is a diagram showing a configuration of the solenoid type coil 34. In this case, as shown in FIG. 3, the power receiving coil 8 includes a first main surface and a second main surface arranged in the thickness direction, the ferrite 32 formed in a plate shape, and the coil wire is the first main surface. And a coil 34 that is wound around the ferrite 32 and alternately arranged along the second main surface. In the solenoid type coil 30, the connecting portion that connects the first portion along the first main surface and the second portion along the second main surface is in the same direction as the thickness direction on the front side in FIG. 3 is arranged so as to be inclined with respect to the thickness direction on the back side in FIG.

  FIG. 4 is a diagram illustrating an example of the magnetic flux distribution during power transmission when the solenoid type coil 34 is used as the power receiving coil 8. As shown in FIG. 4, a case is assumed where the power receiving coil 8 and the power transmission coil 12 face each other and have a positional relationship in which power can be transmitted.

  At the time of power transmission, as described above, an alternating current flows through the power transmission coil 12, so that a magnetic flux is formed around the power transmission coil 12, and the magnetic flux from the formed power transmission coil 12 is linked to the power reception coil 8. An alternating current flows through the coil 8. When an alternating current flows through the power receiving coil 8, a magnetic flux is also formed around the power receiving coil 8. In the solenoid type coil 34, the magnetic flux is formed so as to exit from one end of the coil 34 and enter the other end of the coil 34.

  The coupling coefficient between the power transmitting device 3 and the power receiving device 4 is determined according to the amount of magnetic flux interlinked, and is more than the coupling coefficient when a coil having a configuration in which a plurality of circular coils described later are arranged is used as the power receiving coil. High value.

  On the other hand, as shown in the distribution of magnetic flux formed around the coil 34 in FIG. 4, in the solenoid type coil 34, the magnetic flux spreads outward from both ends of the coil 34. Leakage magnetic flux (electromagnetic wave leakage) is generated in the (direction along the first main surface or the second main surface of the ferrite 32) or upward (on the side opposite to the position where the power transmission coil 12 is provided). Therefore, the magnetic field intensity around the vehicle may increase.

  Next, the case where a coil (so-called DD coil) configured by arranging circular coils is applied as the power receiving coil 8 will be described with reference to FIG. FIG. 5 is a diagram illustrating a configuration of a coil 40 configured by arranging circular coils. In this case, as shown in FIG. 5, the power receiving coil 8 includes a first main surface and a second main surface arranged in the thickness direction, the ferrite 42 formed in a plate shape, and the coil wire is the first main surface. 42a and the coil 40 wound so as to be along the second main surface 42b which is one of the second main surface 42b. The coil 40 includes a first circular coil 44 and a second circular coil 46 arranged in a spiral shape.

  FIG. 6 is a diagram schematically showing the shape of the coil 40 as viewed from the thickness direction of the ferrite 42. As shown in FIG. 6, the shape of the first circular coil 44 and the shape of the second circular coil 46 are formed such that the winding directions are opposite to each other. And the coil end part 44b of the coil end parts 44a and 44b of the 1st circular coil 44 and 46b of the coil end parts 46a and 46b of the 2nd circular coil are connected, and the coil 40 is formed. . The coil end 44 a of the first circular coil 44 of the coil 40 and the coil end 46 a of the second circular coil 46 are connected to the rectifier 6.

  FIG. 7 is a diagram illustrating an example of a magnetic flux distribution during power transmission when a coil 40 configured by arranging circular coils is used as a power receiving coil. As shown in FIG. 7, it is assumed that the power receiving coil 8 and the power transmission coil 12 face each other and have a positional relationship where power can be transmitted.

  At the time of power transmission, as described above, an alternating current flows through the power transmission coil 12, so that a magnetic flux is formed around the power transmission coil 12, and the magnetic flux from the formed power transmission coil 12 is linked to the power reception coil 8. An alternating current flows through the coil 8. When an alternating current flows through the power receiving coil 8, a magnetic flux is formed around the first circular coil 44 and the second circular coil 46 of the coil 40.

  Here, since the winding direction of the coil wire of the first circular coil 44 and the winding direction of the coil wire of the second circular coil 46 are opposite to each other, the first circular coil 44 is adjacent to the second circular coil 46. Of the second circular coil 46 and the portion adjacent to the first circular coil 44 of the second circular coil 46 are combined to form a magnetic flux that straddles both adjacent portions. The magnetic flux formed so as to straddle both adjacent portions is distributed so as to swell toward the power transmission device 3 and is linked to the power transmission coil 12.

  In such a coil 40, as shown in the distribution of magnetic flux formed around the coil 40 in FIG. 7, the magnetic flux formed in the coil 40 is distributed so as to swell toward the power transmission device 3. Leakage magnetic flux in the horizontal direction (the direction along the first main surface 42a or the second main surface 42b) or upward (on the opposite side to the position where the power transmission coil 12 is provided) from the leakage magnetic flux generated in the solenoid coil 30 Can also be reduced. On the other hand, the coupling coefficient between the power transmission device 3 and the power receiving device 4 when the coil 40 is used is lower than the coupling coefficient when the coil 30 is used. Therefore, in order to enable power transmission of the same level as when the coil 30 is used, the physique and cost of the power transmission device may be higher than when the coil 30 is used. Thus, the coil shape used for non-contact power transmission requires further improvement in order to improve the coupling coefficient while suppressing the generation of leakage magnetic flux.

  Therefore, in the present embodiment, as the power receiving coil 8, a coil having the following configuration different from the above-described coils 30 and 40 is used. Specifically, the coil unit according to the present embodiment includes a first main surface and a second main surface arranged in the thickness direction, the ferrite formed in a plate shape, and the coil wire is connected to the first main surface. A coil that is wound around a ferrite and alternately arranged along the second main surface is provided. The coil includes a first portion and a second portion that are in contact with the first main surface and are adjacent to each other, and a third portion that is in contact with the second main surface. The fourth portion that connects the first portion and the third portion has an angle that is inclined with respect to the thickness direction. The third portion is in contact with the second main surface at a position that is shifted in the arrangement direction from the first portion to the second portion with respect to the position facing the second portion with the ferrite interposed therebetween.

  In this way, the solenoid type coil can direct the flow of magnetic flux as leakage flux toward the power transmission side or the power reception side, so that a high coupling coefficient can be obtained while suppressing generation of leakage magnetic flux.

  Hereinafter, a specific configuration example of the coil unit according to the present embodiment will be described using FIGS. 8 and 9 in comparison with the coil 30 shown in FIG. 3 and the coil 40 shown in FIGS. .

  A part of the configuration of the coil unit according to the present embodiment is shown in FIGS. FIG. 8 is a perspective view showing a configuration example of the coil 20 in the present embodiment. FIG. 9 is a diagram illustrating a configuration example of the coil 20 in the present embodiment.

  As shown in FIGS. 8 and 9, the ferrite 22 includes a first main surface 22a and a second main surface 22b arranged in the thickness direction, and is formed in a plate shape. The coil 20 is wound around the ferrite 22 so that the coil wire alternately follows the first main surface 22a and the second main surface 22b.

  The first main surface 22a is arranged along the width direction of the ferrite 22 so that the first surface portions 24a, 25a, 26a, 27a, 28a, and 29a of the coil 20 are in contact with each other. And it arrange | positions along the width direction of the ferrite 22 so that each of 2nd surface part 24b, 25b, 26b, 27b, 28b, 29b may contact with the 2nd main surface 22b. The first surface portions 24 a to 29 a of the coil 20 of the first main surface 22 a and the second surface portions 24 b to 29 b of the second main surface 22 b are connected at both ends in the width direction of the ferrite 22.

  In FIG. 9, straight lines connecting the first surface portions 24 a to 29 a of the first main surface 22 a and the second surface portions 24 b to 29 b of the second main surface 22 b are the first at one end in the width direction of the ferrite 22. The connection relationship between the surface portions 24a to 29a and the second surface portions 24b to 29b of the second main surface 22b is shown.

  As shown in FIGS. 8 and 9, the first surface portion 24 a and the second surface portion 24 b are connected by a first connection portion 24 c at one end in the width direction of the ferrite 22. Further, the first surface portion 25 a and the second surface portion 25 b are connected by a first connection portion 25 c at one end in the width direction of the ferrite 22. Further, the first surface portion 26 a and the second surface portion 26 b are connected by a first connection portion 26 c at one end in the width direction of the ferrite 22. Furthermore, the first surface portion 27 a and the second surface portion 27 b are connected by a first connection portion 27 c at one end in the width direction of the ferrite 22. Further, the first surface portion 28 a and the second surface portion 28 b are connected by a first connection portion 28 c at one end in the width direction of the ferrite 22. Furthermore, the first surface portion 29 a and the second surface portion 29 b are connected by a first connection portion 29 c at one end in the width direction of the ferrite 22.

  Although not particularly illustrated, the second surface portion 24b and the first surface portion 25a are connected by the second connection portion at the other end portion in the width direction of the ferrite 22. Furthermore, the second surface portion 25 b and the first surface portion 26 a are connected by the second connection portion at the other end in the width direction of the ferrite 22. Further, the second surface portion 26 b and the first surface portion 27 a are connected by the second connection portion at the other end portion in the width direction of the ferrite 22. Further, the second surface portion 27 b and the first surface portion 28 a are connected by the second connection portion at the other end portion in the width direction of the ferrite 22. Further, the second surface portion 28 b and the first surface portion 29 a are connected by the second connection portion at the other end in the width direction of the ferrite 22.

  The longitudinal direction of the first connection portions 24 c, 25 c, and 26 c has a predetermined angle so as to be inclined with respect to the thickness direction of the ferrite 22. The first connection portions 27c, 28c, and 29c are disposed symmetrically with the first connection portions 24c, 25c, and 26c with respect to the axis 1 indicated by the broken line in FIG. Therefore, the longitudinal direction of the first connection portions 24 c, 25 c, and 26 c also has a predetermined angle so as to be inclined with respect to the thickness direction of the ferrite 22.

  Furthermore, in the present embodiment, the second surface portion 24b is displaced in the arrangement direction from the first surface portion 24a to the first surface portion 25a, rather than a position facing the first surface portion 25a with the ferrite 22 in between. It contacts the second main surface 22b at a position. Similarly, the second surface portion 25b has a second main surface at a position shifted in the arrangement direction from the first surface portion 25a to the first surface portion 26a, rather than a position facing the first surface portion 26a with the ferrite 22 in between. 22b is contacted. Similarly, the second surface portion 26b has a second main surface at a position shifted in the arrangement direction from the first surface portion 26a to the first surface portion 27a with respect to the first surface portion 27a and the position facing the ferrite 22 therebetween. 22b is contacted.

  The operation of the coil unit in which the coil 20 having such a configuration is used will be described. For example, a case is assumed where the power receiving coil 8 and the power transmission coil 12 face each other and have a positional relationship in which power can be transmitted.

  During power transmission, as described above, when an alternating current flows through the power transmission coil 12, a magnetic flux is formed around the power transmission coil 12, and the magnetic flux from the formed power transmission coil 12 is linked to the power reception coil. AC current flows through 8. When an alternating current flows through the power receiving coil 8, a magnetic flux is formed around the coil 20.

  The first connection portions 24c, 26c, and 28c are arranged to have a predetermined angle with respect to the thickness direction. Further, the second surface portions 24b and 25b on one end side of the coil 20 are respectively adjacent to the first surface portions 24a and 25a connected via the first connection portions 24c and 25c, respectively. The position is shifted in the arrangement direction from the second surface portion 24b to 25b from the position corresponding to 26a. Thereby, the flow of magnetic flux formed from one end of the coil 20 is directed to the power transmission device 3 side.

  In addition, the first surface portions 27a, 28a, 29a, the second surface portions 27b, 28b, 29b and the first connection portions 27c, 28c, 29c on the other end side of the coil 20 are the first surface portions 24a, 25a, 26a, the second surface portions 24b, 25b, and 26b and the first connection portions 24c, 25c, and 26c and the axis l in FIG. Thereby, the flow of the magnetic flux formed from the other end of the coil 20 is also directed to the power transmission device 3 side.

  As a result, the leakage magnetic flux in the direction along the first main surface 22a or the second main surface 22b of the ferrite 22 can be reduced as compared with the solenoid type coil 30. As a result, the amount of magnetic flux interlinked with the solenoid type coil 30 can be increased. Therefore, when the coupling coefficient between the power transmission device 3 and the power reception device 4 is used as the power reception coil, the solenoid type coil 30 is used. The coupling coefficient or the coil 40 configured by arranging circular coils can be set to a higher value than the coupling coefficient when used as a power receiving coil.

  As described above, according to the coil unit according to the present embodiment, the flow of magnetic flux at the coil end can be directed to the power transmission device 3 side. Therefore, it is possible to provide a coil unit that can obtain a high coupling coefficient while suppressing generation of leakage magnetic flux.

Hereinafter, modifications will be described.
In the above-described embodiment, the case where the coil 20 is used as the power receiving coil 8 has been described. For example, the coil 20 may be used as the power transmitting coil 12.

  Further, in the above-described embodiment, the coil wire is wound around the ferrite 22 for convenience of explanation. However, for example, a resin cover or the like may be provided between the coil wire and the ferrite 22.

  Further, in the above-described embodiment, the case where the second surface portion 24b of the coil 20 is provided at a position facing the first surface portion 26a has been described as a configuration example of the coil 20, but the configuration is particularly limited to such a configuration. It is not a thing.

  For example, the first surface portions 24a, 25a, and 26a of the coil 20 are disposed so as to be spaced apart from the second surface portions 24b, 25b, and 26b by a predetermined interval in the arrangement direction of the first surface portions 24a and 25a. The first surface portions 27a, 28a, and 29a may be arranged so as to be separated from the second surface portions 27b, 28b, and 29b by a predetermined interval in the arrangement direction. In this modification, the first surface portions 24a, 25a, 26a of the coil 20 and the second surface portions 24b, 25b, 26b are separated from each other, and the first surface portions 27a, 28a, 29a and the second surface portions 27b, 28b, Since the configuration other than the separation from 29b is the same as the configuration of coil 20 described with reference to FIGS. 8 and 9, detailed description thereof will not be repeated.

  FIG. 10 is a diagram illustrating an example of a magnetic flux distribution during power transmission when the coil 20 according to the present modification is used for the power receiving device 4. The first surface portions 24a, 25a, and 26a and the second surface portions 24b, 25b, and 26b are disposed so as to be spaced apart from each other by a predetermined distance, and the first surface portions 27a, 28a, and 29a and the second surface portions 27b and 28b are disposed. , 29b so as to be spaced apart from each other by a predetermined distance, as shown in FIG. 10, the lateral direction of the coil 20 (direction along the first main surface 22a or the second main surface 22b of the ferrite 22) or upward direction The leakage magnetic flux to the side opposite to the position where the power transmission coil 12 is provided can be suppressed at the same level as the case of the coil 40 shown in FIG. 7, and between the power transmission device 3 and the power reception device 4. Can be set to a value equal to or greater than the coupling coefficient when the solenoid type coil 30 is used.

In addition, you may implement the above-mentioned modification combining all or one part suitably.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present disclosure is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Contactless charging system, 2 Vehicle, 3 Power transmission device, 4 Power receiving device, 5,14 Resonator, 6 Rectifier, 7 Battery, 8 Power receiving coil, 9,13 Capacitor, 10 Power supply, 11 Converter, 12 Power transmission coil, 20 , 30, 40 Coil, 22, 32, 42 Ferrite, 22a, 42a First main surface, 22b, 42b Second main surface, 24a, 25a, 26a, 27a, 28a, 29a First surface portion, 24b, 25b, 26b , 27b, 28b, 29b second surface portion, 24c, 25c, 26c, 27c, 28c, 29c first connection portion, 44 first circular coil, 46 second circular coil.

Claims (1)

A ferrite including a first main surface and a second main surface arranged in a thickness direction and formed in a plate shape;
A coil wire wound around the ferrite so as to alternately follow the first main surface and the second main surface, and a coil disposed in a spiral shape,
The coil includes a first portion and a second portion that are in contact with the first main surface and are adjacent to each other, and a third portion that is in contact with the second main surface,
The fourth part connecting the first part and the third part has an angle that is oblique to the thickness direction,
The third unit is in contact with the second main surface at a position shifted in the arrangement direction from the first part to the second part from a position facing the second part across the ferrite. .

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