Coil unit, contactless power supply system, and coil structure

Abstract

The purpose of the present invention is to provide a coil unit, a contactless power supply system, and a coil structure capable of increasing the degree of freedom for disposing a magnetic core while maintaining the strength of magnetic coupling during power supply between a power transmission coil and a power reception coil.　This coil unit (100) has a power transmission coil (21) and a power reception coil (31). A magnetic core (50) that strengthens magnetic coupling between the power transmission coil (21) and the power reception coil (31) during power supply includes: a connection part (53) that faces a portion of the power transmission coil (21) in a z-axis direction; a penetration part (51) that penetrates the inside of the power transmission coil (21); and a crossing part (52) that sandwiches a portion of the power transmission coil (21) with the penetration part (51). During power supply, the penetration part (51) penetrates the power transmission coil (21) and the power reception coil (31), and the crossing part (52) crosses the power transmission coil (21) and the power reception coil (31).

Description

Coil unit, non-contact power supply system and coil structure

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

[0002] A contactless power transfer system transmits power from a power transmitter to a power receiver using contactless power transfer technology. Contactless power transfer technology transmits power between two coils spaced apart. One type of contactless power transfer technology utilizes magnetic coupling between a power transmitter coil and a power receiver coil to transmit power. In such power transfer methods, the strength of the magnetic coupling between the power transmitter coil and the power receiver coil is an important parameter. For example, increasing the magnetic coupling can improve power transfer efficiency. To strengthen the magnetic coupling, a structure that promotes magnetic field generation by placing a magnetic material (a magnetic core) near the coil is commonly adopted. However, using a large amount of magnetic material increases the weight and makes the device difficult to handle. It also increases costs. For this reason, the structure and arrangement of the magnetic core are extremely important in contactless power transfer technology, and various structures have been proposed. For example, in the charging connector disclosed in Patent Document 1, the primary core (core of the power supply side connector) that forms the power supply side connector together with the primary coil and the secondary core (core of the vehicle side connector) that forms the vehicle side connector together with the secondary coil occupy different areas from each other.

[0003] Japanese Patent Application Publication No. 10-075538

[0004] However, the technology disclosed in Patent Document 1 employs a structure in which the coil and the core are mated. Therefore, if there is a change in the coil structure, such as the shape or size of the coil, the shape and arrangement of the core must also be changed accordingly. When it is necessary to match the shapes of the core and the coil in this way, there is a problem in that there is no flexibility (degree of freedom) in design.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a coil unit, a contactless power supply system, and a coil structure that can increase the freedom of magnetic core placement while maintaining the strength of magnetic coupling between the transmitting coil and the receiving coil during power supply.

[0006] The coil unit of the present disclosure has a power transmission coil and a power receiving coil that have parallel winding axes and are separated by a distance in the winding axis direction, which is the direction of the winding axis; when power is supplied, the power transmission coil and the power receiving coil are magnetically coupled to transmit AC power from the power transmission coil to the power receiving coil; and is equipped with a magnetic body that strengthens the magnetic coupling between the power transmission coil and the power receiving coil when power is supplied.When one of the power transmission coil and the power receiving coil is designated as the first coil and the other as the second coil, the magnetic body includes a connection portion that faces a part of the one coil in the winding axis direction, a through portion that protrudes from the connection portion in the winding axis direction and penetrates the inside of the one coil, and an intersection portion that protrudes from the connection portion in the winding axis direction and has a part sandwiched between the through portion and the one coil; when power is supplied, the through portion penetrates the one coil and the other coil, and the intersection portion intersects the one coil and the other coil.

[0007] The coil structure of the present disclosure is also a coil structure provided with a magnetic body and having a coil used for contactless power supply, wherein the magnetic body includes a connection portion that faces a portion of the coil in the winding axis direction, which is the direction of the winding axis of the coil, a through portion that protrudes from the connection portion in the winding axis direction and penetrates the inside of the coil, and an intersection portion that protrudes from the connection portion in the winding axis direction and sandwiches a portion of the through portion, wherein the coil is a power transmitting coil that magnetically couples with another coil spaced apart in the winding axis direction during power supply and transmits power between the other coil via magnetic energy or a power receiving coil to which power is transmitted, and the magnetic body is a magnetic body that strengthens the magnetic coupling between the coil and the other coil during power supply, the through portion penetrates the inside of the coil and the other coil during power supply, and the intersection portion intersects one coil and the other coil.

[0008] According to the coil unit, contactless power supply system, or coil structure of the present disclosure, the degree of freedom in arranging the magnetic core can be increased while maintaining the strength of the magnetic coupling between the power transmitting coil and the power receiving coil during power supply.

[0009] 14 is a configuration diagram showing a contactless power supply system according to a first embodiment. FIG. 15 is a diagram showing configuration examples of a power transmitting resonant circuit and a power receiving resonant circuit according to the first embodiment. FIG. 16 is a diagram showing a configuration example of a power receiving circuit according to the first embodiment. FIG. 17 is a perspective view showing a configuration example of a coil unit according to the first embodiment. FIG. 18 is a side view showing a configuration example of a coil unit according to the first embodiment. FIG. 19 is a plan view showing a configuration example of a coil unit according to the first embodiment. FIG. 19 is a diagram showing an application example of the coil unit according to the first embodiment. FIG. 20 is a diagram explaining the arrangement of each coil in an application example of the coil unit according to the first embodiment. FIG. 21 is a perspective view showing a configuration example of a coil unit according to a second embodiment. FIG. 22 is a side view showing a configuration example of a coil unit according to the second embodiment. FIG. 23 is a plan view showing a configuration example of a coil unit according to the second embodiment. FIG. 24 is a perspective view showing a configuration example of a coil unit according to the third embodiment. FIG. 25 is a side view showing a configuration example of a coil unit according to the third embodiment. FIG. 26 is a side view showing a configuration example of a coil unit according to the third embodiment, in which magnetic cores are arranged on corresponding linear portions of the power transmitting coil and the power receiving coil. FIG. 27 is a diagram explaining the magnetic core and the other magnetic core shown in FIG. 25. FIG. 28 is a perspective view showing a configuration example of a coil unit according to a fourth embodiment. 10 is a side view showing a configuration example of a coil unit in embodiment 4. FIG. 11 is a perspective view showing an example in which a magnetic core and a second magnetic core are arranged at corners of a power transmitting coil and a power receiving coil, respectively. FIG. 12 is a perspective view showing an example in which magnetic units are arranged on hexagonal power transmitting coils and power receiving coils, respectively.

[0010] Embodiment 1. Embodiment 1 will be described with reference to FIGS. 1 to 8. FIG. 1 is a configuration diagram showing a contactless power transfer system in embodiment 1. The contactless power transfer system 1000 includes a power transmitting side device 1100 having an AC power supply 10 and a power transmitting resonant circuit 20, and a power receiving side device 1200 having a power receiving resonant circuit 30 and a power receiving circuit 40. The AC power supply 10 supplies AC power to the power transmitting resonant circuit 20. The AC power supplied from the AC power supply 10 is converted into magnetic energy in the power transmitting resonant circuit 20. The magnetic energy generated in the power transmitting resonant circuit 20 is transmitted to the power receiving resonant circuit 30 and converted into AC power in the power receiving resonant circuit 30. This AC power is sent to the power receiving circuit 40. The AC power sent from the power receiving resonant circuit 30 to the power receiving circuit 40 is used in the power receiving circuit 40.

[0011] The AC power supply 10 is a power supply that outputs a high-frequency voltage or a high-frequency current. The AC power supply 10 is not limited to being configured solely as an AC current source or an AC voltage source, but may also be configured to combine these with a power converter such as an inverter or a DC / DC converter. The AC voltage output by the AC power supply 10 may include a single frequency or may include multiple frequency components. The output waveform of the AC power supply 10 may be a sinusoidal waveform, a triangular waveform, a rectangular waveform, or the like.

[0012] The power transmitter resonant circuit 20 and the power receiver resonant circuit 30 will be described. FIG. 2 is a diagram showing an example configuration of the power transmitter resonant circuit and the power receiver resonant circuit according to the first embodiment. The power transmitter resonant circuit 20 includes a power transmitter coil 21 and at least one power transmitter-side resonant capacitor 22. The power transmitter resonant circuit 20 may also include a resonant coil and a resonant capacitor other than the power transmitter coil 21 and the power transmitter-side resonant capacitor 22. The power transmitter resonant circuit 20 is designed so that its resonant frequency is the output frequency of the AC power supply 10 or in its vicinity. When the output waveform of the AC power supply 10 is a rectangular waveform or the like and includes harmonic components, the power transmitter resonant circuit 20 is generally designed to satisfy the resonance condition for the fundamental component of the output waveform, i.e., the resonant frequency of the power transmitter resonant circuit 20 is the frequency of the fundamental component. However, the power transmitter resonant circuit 20 may also be designed to satisfy the resonance condition for the harmonic components of the output waveform. The power transmitting resonant circuit 20 shown in FIG. 2 is one of various resonant circuit configurations, and does not limit the configuration of the power transmitting resonant circuit 20 .

[0013] The power receiver resonant circuit 30 includes a power receiver coil 31 and at least one power receiver-side resonant capacitor 32. The power receiver resonant circuit 30 may include a resonant coil and a resonant capacitor separate from the power receiver coil 31 and the power receiver-side resonant capacitor 32. The power receiver resonant circuit 30 is designed so that its resonant frequency is at or near the output frequency of the AC power source 10. When the output waveform of the AC power source 10 is a rectangular wave or the like and includes harmonic components, the power receiver resonant circuit 30 is generally designed to satisfy the resonance condition for the fundamental wave component of the output waveform, i.e., so that the resonant frequency of the power receiver resonant circuit 30 is the frequency of the fundamental wave component. However, the power receiver resonant circuit 30 may also be designed to satisfy the resonance condition for the harmonic components of the output waveform. Note that the power receiver resonant circuit 30 shown in FIG. 2 has a configuration in which one power receiver-side resonant capacitor 32 is connected in series to the power receiver coil 31. However, this configuration shows one of various resonant circuit configurations and does not limit the configuration of the power receiver resonant circuit 30.

[0014] The power transmitting coil 21 and the power receiving coil 31 are strongly magnetically coupled when the power transmitting resonant circuit 20 and the power receiving resonant circuit 30 are in a resonant state. With the power transmitting coil 21 and the power receiving coil 31 in a strongly magnetically coupled state, AC power is transmitted from the power transmitting coil 21 to the power receiving coil 31. In this manner, the power transmitting coil 21 and the power receiving coil 31 function as a coil unit, which is a contactless power transfer coil. The configuration of the power transmitting coil 21 and the power receiving coil 31 as a coil unit will be described later.

[0015] The power receiving circuit 40 will be described. FIG. 3 is a diagram illustrating an example configuration of the power receiving circuit according to the first embodiment. The power receiving circuit 40 includes a rectifier circuit 41, a filter 42, and a load 43. The power receiving circuit 40 converts AC power supplied from the power receiving resonant circuit 30 into DC power for use. The rectifier circuit 41 is a full-bridge diode rectifier circuit including diodes 41a to 41d and rectifies the AC power supplied from the power receiving resonant circuit 30. The filter 42 attenuates high-frequency AC components contained in the output of the rectifier circuit 41. The load 43 includes an electrical device that consumes the DC power converted by the rectifier circuit 41 and the filter 42, a battery that stores the power, or the like. The load 43 may include a power conversion circuit such as a voltage stabilization circuit. Note that the configuration of the power receiving circuit 40 illustrated in FIG. 3 is merely an example, and some elements may be omitted. For example, the rectifier circuit 41 may be omitted and the AC power may be consumed directly. Moreover, the filter 42 may be omitted and DC power containing high-frequency AC components may be consumed by the load 43. The circuit configuration of the rectifier circuit 41 or the filter 42 may be different. In addition, various modified examples having functions equivalent to those of the power receiving circuit 40 described above may be used.

[0016] FIG. 4 is a perspective view showing an example of the configuration of the coil unit according to the first embodiment. Note that FIG. 4 illustrates a non-powered state in which the power transmitting coil 21 and the power receiving coil 31 are spaced apart by a certain distance or more. The coil unit 100 includes the power transmitting coil 21, the power receiving coil 31, and a magnetic core 50, i.e., a magnetic body. The power transmitting coil 21 and the power receiving coil 31 are each a rectangular coil wound around an imaginary winding axis along an imaginary plane perpendicular to the winding axis. The winding axis of the power transmitting coil 21 and the winding axis of the power receiving coil 31 are parallel. The power transmitting coil 21 has linear portions 21a and 21c that are parallel to each other, and linear portions 21b and 21d that are parallel to each other. The linear portions 21a and 21c are perpendicular to the linear portions 21b and 21d. The power receiving coil 31 has linear portions 31a and 31c that are parallel to each other, and linear portions 31b and 31d that are parallel to each other. The linear portions 31a and 31c are perpendicular to the linear portions 31b and 31d.

[0017] For the following explanation, the coordinate axes are defined as follows. First, as shown in FIG. 4 , the direction in which one side of the rectangularly wound power transmitting coil 21 and power receiving coil 31 extends (the direction in which straight portions 21b, 21d, 31b, and 31d extend), is defined as the x-axis direction, and the direction in which the side perpendicular to the one side extends (the direction in which straight portions 21a, 21c, 31a, and 31c extend), is defined as the y-axis direction. The direction parallel to the winding axes of the power transmitting coil 21 and power receiving coil 31 is defined as the z-axis direction. In this case, the xy plane defined by the x-axis and y-axis corresponds to the imaginary plane described above, and therefore the x-axis and y-axis directions are perpendicular to the z-axis direction. For ease of explanation, the upward direction in the drawing is defined as the +z direction, and the downward direction in the drawing is defined as the −z direction. One direction along the x-axis is defined as the +x direction, and the direction opposite to the +x direction is defined as the −x direction. Also, one direction along the y-axis is defined as the +y direction, and the direction opposite to the +y direction is defined as the −y direction.

[0018] 4, the power transmitting coil 21 and the power receiving coil 31 are separated in the direction of their respective winding axes (z-axis direction) by a separation distance L. The separation distance L is the distance between the top surface of the power transmitting coil 21 and the bottom surface of the power receiving coil 31.

[0019] The magnetic core 50 is made of a magnetic material and strengthens the magnetic coupling between the power transmission coil 21 and the power receiving coil 31 during power supply. The magnetic core 50 is disposed so as to cover a portion of the power transmission coil 21, more specifically, a portion of the lower side of the straight portion 21a. The magnetic core 50 includes a through portion 51 that protrudes in the +z direction and penetrates the inside of the power transmission coil 21, an intersection portion 52 that faces the through portion 51 and intersects with the power transmission coil 21 on the outside of the power transmission coil 21, and a connection portion 53 that extends along the x-axis and y-axis directions and connects the through portion 51 and the intersection portion 52. The connection portion 53 faces one surface of the portion of the straight portion of the power transmission coil 21. In the example shown in FIG. 4 , the connection portion 53 faces a portion of the lower surface (the surface in the −z direction) of the straight portion 21a. Furthermore, since each straight portion of the power transmission coil 21 extends in the x-axis or y-axis direction, the connection portion 53 extends parallel to each straight portion of the power transmission coil 21. In Figure 4, the magnetic core 50 is disposed near the straight portion 21a (for example, at a position within 50% or less of the separation distance L from the straight portion 21a). The width direction of the straight portion 21a is the x-axis direction, and the length direction is the y-axis direction. The x-axis direction of the connection portion 53 is also the width direction, and the y-axis direction is the length direction. In other words, the y-axis direction is the magnetic material extension direction. The x-axis direction is also the opposing direction of the through portion 51 and the intersection portion 52.

[0020] In the non-powered state, the through portion 51 of the magnetic core 50 penetrates only the inside of the power transmission coil 21 in the z-axis direction. The intersection portion 52 intersects only with the power transmission coil 21 (straight portion 21a). As a result, a portion of the straight portion 21a is sandwiched between the through portion 51 and the intersection portion 52. The magnetic core 50 is fixed to the power transmission coil 21 via an intermediate member (not shown).

[0021] 4 shows a configuration example in which the magnetic core 50 is disposed below and near the power transmitting coil 21, but the magnetic core 50 may also be disposed near the power receiving coil 31. That is, when one of the power transmitting coil 21 and the power receiving coil 31 is designated as one coil and the other is designated as the other coil, the magnetic core 50 may be disposed near one of the coils. The above-mentioned separation distance L is the distance between one surface of one coil and the opposing surface of the other coil. When the magnetic core 50 is disposed near the power receiving coil 31, the magnetic core 50 is fixed to the power receiving coil 31 via an intermediate member. The magnetic core 50 is also disposed above the power receiving coil 31. That is, the magnetic core 50 is disposed on the side of one coil opposite the side facing the other coil.

[0022] In the example shown in FIG. 4 , the magnetic core 50 is positioned opposite a portion of the straight portion 21a. The magnetic core 50 can be positioned anywhere on the straight portion 21a. That is, the magnetic core 50 can be moved in the x-axis and y-axis directions as long as it does not interfere with the power transmission coil 21. The magnetic core 50 may also be positioned near one of the other straight portions (straight portions 21b to 21d). Focusing on the through portion 51 and the intersection 52, the through portion 51 and the intersection 52 are arranged to sandwich a portion of the power transmission coil 21 or the power receiving coil 31, rather than the entirety of the power transmission coil 21 or the power receiving coil 31. This means that a common magnetic core 50 can be used even if the shapes and sizes of the power transmission coil 21 and the power receiving coil 31 are different. This allows for a high degree of freedom in the placement and design of the magnetic core 50.

[0023] FIG. 5 is a side view showing an example of the configuration of the coil unit according to the first embodiment, as viewed from the −y direction. FIG. 5 illustrates a state during power supply, in which the power transmitting coil 21 and the power receiving coil 31 are disposed closer to each other than in the non-power supply state shown in FIG. 4 . That is, the separation distance L* during power supply shown in FIG. 5 is smaller than the separation distance L in FIG. 4 . The separation distance L* during power supply may be, for example, 10% or less of the maximum width (the axial length of the straight portion 21 a, etc.) of the power transmitting coil 21 and the power receiving coil 31. However, because the strength of the magnetic coupling between the power transmitting coil 21 and the power receiving coil 31 also depends on the dimensions of the power transmitting coil 21 and the power receiving coil 31, the separation distance L* during power supply is not limited to the above. While the through portion 51 penetrates only the inside of the power transmitting coil 21 in the non-power supply state, it penetrates the inside of the power transmitting coil 21 and the power receiving coil 31 during power supply. The intersection 52 intersects only with the power transmitting coil 21 in the non-powered state, but intersects both the power transmitting coil 21 and the power receiving coil 31 when power is being supplied. The through-hole 51 and the intersection 52 sandwich only the power transmitting coil 21 (straight portion 21a) between them in the non-powered state, but when power is being supplied, they are arranged to sandwich both the power transmitting coil 21 and the power receiving coil 31 (straight portion 21a and straight portion 31a) between them. As shown in FIG. 5 , the through-hole 51 protrudes in the +z direction from the end of the connection portion 53 on the −x direction side, i.e., the end facing inward from the power transmitting coil 21 and the power receiving coil 31. The intersection 52 protrudes in the +z direction from the end of the connection portion 53 on the +x direction side, i.e., the end facing outward from the power transmitting coil 21 and the power receiving coil 31. This results in a U-shape for the magnetic core 50 when viewed from the −y direction. Thus, through portion 51 and intersecting portion 52 protrude from one end and the other end of connecting portion 53 in a direction parallel to the winding axis (z-axis direction) and are provided so as to intersect with the xy plane.

[0024] Because the through portion 51 penetrates both the power transmitting coil 21 and the power receiving coil 31 during power supply, the length L2 of the through portion 51 in the z-axis direction, excluding the thickness of the connection portion 53 (the length in the z-axis direction), is preferably longer than the distance L1, which is the sum of the thickness of the power transmitting coil 21, the thickness of the power receiving coil 31, and the distance (separation distance L*) between the power transmitting coil 21 and the power receiving coil 31. Similarly, the length L3 of the intersection portion 52 in the z-axis direction, excluding the thickness of the connection portion 53, is preferably longer than the distance L1. Setting the distance L1, the length L2, and the length L3 in this manner can increase the amount of magnetic flux interlinking with both the power transmitting coil 21 and the power receiving coil 31, thereby strengthening the magnetic coupling between the power transmitting coil 21 and the power receiving coil 31 during power supply.

[0025] In FIG. 5, the length L2 of the through portion 51 excluding the thickness of the connection portion 53 and the length L3 of the intersection portion 52 excluding the thickness of the connection portion 53 are equal, but they may be set to different lengths.

[0026] In the width direction (x-axis direction) of connecting portion 53, length L5 of the portion where power transmitting coil 21 and power receiving coil 31 overlap with magnetic core 50 is preferably set to a length less than half of length L4 of x-axis direction of power transmitting coil 21 and power receiving coil 31. In other words, in a side view seen from the y-axis direction, which is the magnetic material extension direction, the length of the portion where connecting portion 53 and power transmitting coil 21 overlap in the x-axis direction, which is the opposing direction, is preferably shorter than half the length of power transmitting coil 21 in the x-axis direction and half the length of power receiving coil 31 in the x-axis direction.

[0027] To achieve stronger magnetic coupling, the magnetic core 50 must be made larger. However, by setting the width and position of the magnetic core 50 so that the lengths L4 and L5 satisfy the above relationship, the volume occupied by the magnetic core 50 can be reduced. Reducing the volume occupied by the magnetic core 50 in this manner also contributes to a more compact and lightweight device. Furthermore, the air gap in the magnetic flux path generated when power is transmitted from the power transmitting coil 21 to the power receiving coil 31 is shortened. This reduces magnetic resistance and strengthens magnetic coupling. Note that the example in FIG. 5 assumes that the magnetic core 50 is disposed near the power transmitting coil 21. In this case, the connection portion 53 is disposed below the power transmitting coil 21. When the magnetic core 50 is disposed near the power receiving coil 31, the connection portion 53 is disposed above the power receiving coil 31. Furthermore, in order to fix the relative positions of the power transmission coil 21 and the power receiving coil 31, and the relative positions of the power transmission coil 21 and the magnetic core 50, structures such as jigs and cases are actually provided as intermediate members, but these intermediate members are not shown in Figure 5.

[0028] FIG. 6 is a plan view showing an example of the configuration of the coil unit according to the first embodiment. This view is taken from the +z direction, and the power transmission coil 21 is not visible, but it overlaps with the power receiving coil 31. In FIG. 6, length L6 indicates the length of the magnetic core 50 in the y-axis direction. Length L7 indicates the length of the power receiving coil 31 (and the power transmission coil 21) in the x-axis direction and the y-axis direction inside the power receiving coil 31. Note that, in the example shown in FIG. 6, the lengths of the straight portions of the power transmission coil 21 and the power receiving coil 31 are the same, but the straight portions extending in the x-axis direction and the y-axis direction may be different lengths. The connecting portion 53 of the magnetic core 50 faces only a portion of the straight portion 21a of the power transmission coil 21. Therefore, length L6 is shorter than length L7.

[0029] Length L8 indicates the width (length in the x-axis direction) of a portion inside power transmission coil 21 where connection portion 53 and straight portion 21a do not overlap, and length L9 indicates the width of a portion outside power transmission coil 21 where connection portion 53 and straight portion 21a do not overlap. In other words, length L8 is the distance between the surface on the +x-direction side of through portion 51 and the surface on the −x-direction side of straight portion 21a (straight portion 21a and straight portion 31a when power is being supplied). Length L9 is the distance between the surface on the −x-direction side of intersection 52 and the surface on the +x-direction side of straight portion 21a (straight portion 21a and straight portion 31a when power is being supplied). In this case, width W1 (not shown) of straight portion 21a is length L5 minus the thickness (length in the x-axis direction) of through portion 51 and length L8. Furthermore, the width W2 (not shown) of the connection portion 53, excluding the widths (length in the x-axis direction) of the through portion 51 and the intersection portion 52, is the sum of the length L8, the width W1, and the length L9. Therefore, W2 > W1 holds. That is, the width of the connection portion 53 is greater than the width of the straight portion 21a of the power transmission coil 21. The position of the magnetic core 50 in the x-axis direction can be adjusted by this margin (the difference between the width W2 and the width W1).

[0030] The power transmission coil 21 described above can be said to be a coil structure provided with a magnetic core 50 and having a coil used for contactless power supply. The magnetic core 50 includes a connection portion 53 that faces a portion of the power transmission coil 21 in the z-axis direction, a through portion 51 that protrudes in the z-axis direction from one end of the connection portion 53 in the x-axis direction and penetrates the inside of the power transmission coil 21, and an intersection portion 52 that protrudes in the z-axis direction from the other end of the connection portion 53 and sandwiches a portion of the power transmission coil between the through portion 51 and the power transmission coil. During power supply, the power transmission coil 21 is magnetically coupled to a power receiving coil 31, which is another coil separated from the power transmission coil 31 in the z-axis direction. The power transmission coil 21 that is magnetically coupled to the power receiving coil 31 transmits power to the power receiving coil 31 via magnetic energy. The magnetic core 50 is a magnetic body that strengthens the magnetic coupling between the power transmission coil 21 and the power receiving coil 31 during power supply, and during power supply, the through portion 51 passes through the inside of the power transmission coil 21 and the power receiving coil 31, and the intersection portion 52 intersects with the power transmission coil and the power receiving coil 31. When the magnetic core 50 is disposed near the power receiving coil 31, the power receiving coil 31 corresponds to the coil structure described above.

[0031] In the first embodiment, the through portion 51 protrudes from one end of the connection portion 53, and the intersection portion 52 protrudes from the other end of the connection portion 53. However, it is sufficient that the through portion 51 penetrates only the inside of the power transmitting coil 21 in the unpowered state and penetrates the inside of both the power transmitting coil 21 and the power receiving coil 31 when power is being supplied. Therefore, the through portion 51 does not necessarily have to be provided at one end of the connection portion 53. The same applies to the intersection portion 52; it is sufficient that the through portion 51 intersects only with the power transmitting coil 21 in the unpowered state to sandwich the power transmitting coil 21 between itself and the through portion 51, and that the intersection portion 52 intersects both the power transmitting coil 21 and the power receiving coil 31 between itself and the through portion 51 when power is being supplied. Therefore, it is not necessarily required to provide the intersection portion 52 at the other end of the connection portion 53. As long as the requirements for the through portion 51 and the intersection portion 52 are met, for example, it is conceivable that either or both of the through portion 51 and the intersection portion 52 may be protruded from the center of the connection portion 53 .

[0032] FIG. 7 is a diagram showing an application example of the coil unit according to the first embodiment, illustrating a specific example of a contactless power transfer system 1000. The device (contactless power transfer system 1001) illustrated in FIG. 7 includes a power supply rack 1101 corresponding to the power transmitting side device 1100 and a module device 1201 corresponding to the power receiving side device 1200. As illustrated in FIG. 7 , in the contactless power transfer system 1001, a plurality of module devices 1201 correspond to one power supply rack 1101. Note that in FIGS. 7 and 8 , the up-down direction in the drawings corresponds to the y-axis direction. The plurality of module devices 1201 can be stored in the power supply rack 1101. The module devices 1201 are devices that are stored in the required number according to user requests, and may be, for example, power supplies or control devices. The power supply rack 1101 is a rack-type device that can store the module devices 1201 as described above and supplies power to the module devices 1201. The module device 1201 can be stored in or removed from the power supply rack 1101 by sliding in the z-axis direction.

[0033] FIG. 8 is a diagram illustrating the arrangement of each coil in an application example of the coil unit according to the first embodiment. Note that FIG. 8 illustrates an example of two module devices: a module device 1201A (the upper module device in the figure) and a module device 1201B (the lower module device in the figure). A power transmission coil 21 is attached to the inner rear surface of the power supply rack 1101. Each of the module devices 1201A and 1201B has a power receiving coil 31 attached to a surface facing the inner rear surface of the power supply rack 1101. Note that an AC power source 10 that supplies AC power to the power transmission coil 21 and a power transmission-side resonant capacitor 22 that constitutes the power transmission resonant circuit 20 are not illustrated. These components may be provided in the power supply rack 1101, or may be provided outside the power supply rack 1101 and connected to the power transmission coil 21. Essentially, any configuration is acceptable as long as AC power is supplied to the power transmission coil 21 and resonance occurs in the power transmission coil 21. Although the module device 1201A and the module device 1201B are provided with a power receiving side resonant capacitor 32 and a power receiving circuit 40 inside, the description of these configurations is omitted.

[0034] The positional relationship between the power transmitting coil 21 and the power receiving coil 31 is the same as in the examples shown in FIGS. 4 and 5 , and they are separated by a separation distance (not shown in FIG. 8 ) in the z-axis direction. This separation distance is adjusted to switch between the non-powered state and the power-supplying state. This separation distance is adjusted depending on how far back in the power supply rack 1101 each module device is stored. In FIG. 8 , the module device 1201A, which is stored farther back, is in the non-powered state, and the module device 1201B, which is stored relatively far back, is in the power-supplying state. Similarly to the examples shown in FIGS. 4 and 5 , the magnetic core 50 is disposed near the power transmitting coil 21. The magnetic core 50 also has a similar configuration, including a through portion 51, an intersection portion 52, and a connection portion 53. Similarly to the examples shown in FIGS. 4 and 5 , the through portion 51 penetrates only the power transmitting coil 21 in the non-powered state and penetrates both the power transmitting coil 21 and the power receiving coil 31 during power supply. The through portion 51 does not pass through the power receiving coil 31 of the module device 1201A, but does pass through the power receiving coil 31 of the module device 1201B. The same applies to the intersection of the intersection portion 52 with the power transmitting coil 21 and the power receiving coil 31.

[0035] As shown in the lower module device 1201B, the power transmitting coil 21 and the power receiving coil 31 are arranged so that they are close to each other when the module device 1201B is stored deep in the power supply rack 1101. By arranging the magnetic core 50 in the power supply rack 1101 in this way, each module device 1201 only needs to be equipped with the power receiving coil 31, thereby making it possible to reduce the size and weight of the module device 1201. Although components such as the power transmitting coil 21 and the power receiving coil 31 are exposed in Figure 8, in an actual device, they are incorporated into the device so that they are covered with a resin or the like.

[0036] The power supply rack 1101 is provided with a guide rail 1101a extending in the z-axis direction, and the module device 1201A slides on the guide rail 1101a. The provision of the guide rail 1101a stabilizes the movement of the module devices 1201A and 1201B in the z-axis direction, making it easy to adjust the separation distance between the power transmitting coil 21 and the power receiving coil 31.

[0037] The mounting position of the power transmitting coil 21 in the power supply rack 1101 and the mounting position of the power receiving coil 31 in the module device 1201 are not limited to those shown in Fig. 8. They may be arranged so that the separation distance between the power transmitting coil 21 and the power receiving coil 31 can be adjusted by moving the module device 1201.

[0038] According to the first embodiment, it is possible to increase the degree of freedom in the arrangement of the magnetic core while maintaining the strength of magnetic coupling between the power transmitting coil and the power receiving coil during power supply. More specifically, the coil unit includes a power transmitting coil and a power receiving coil having parallel winding axes and spaced apart by a separation distance along the winding axis, wherein the power transmitting coil and the power receiving coil are magnetically coupled together during power supply to transmit AC power from the power transmitting coil to the power receiving coil, and a magnetic core that strengthens the magnetic coupling between the power transmitting coil and the power receiving coil during power supply, the magnetic core including: a connection portion that faces a portion of the power transmitting coil or the power receiving coil along the winding axis, a through portion that protrudes from one end of the connection portion in the winding axis direction and penetrates the inside of the power transmitting coil or the power receiving coil, and an intersection portion that protrudes from the other end of the connection portion in the winding axis direction and sandwiches a portion of the power transmitting coil or the power receiving coil between the through portion and the magnetic core, wherein during power supply, the through portion penetrates the power transmitting coil and the power receiving coil and the intersection portion intersects with the power transmitting coil and the power receiving coil.

[0039] The magnetic core is positioned to face a portion of either the power transmitting coil or the power receiving coil, and its position can be adjusted to a range that does not interfere with the power transmitting coil or the power receiving coil. This allows for a high degree of freedom in the placement of the magnetic core. Furthermore, the through-holes and crossing portions of the magnetic core are also provided to surround only a portion of the power transmitting coil and the power receiving coil, rather than the entirety of the coil. This allows a common magnetic core to be used even if the power transmitting coil and the power receiving coil have different shapes and sizes. This allows for a high degree of freedom in the placement and design of the magnetic core. Furthermore, during power supply, the through-holes pass through the insides of both the power transmitting coil and the power receiving coil, and the crossing portions cross both the power transmitting coil and the power receiving coil. This increases the amount of magnetic flux interlinking with both coils, thereby strengthening the magnetic coupling. This maintains the magnetic core's effect of strengthening the magnetic coupling between the power transmitting coil and the power receiving coil.

[0040] Furthermore, in the opposing direction of the through-hole and the intersection, the length of the portion where the connection portion of the magnetic core and the power transmission coil overlap is shorter than half the length of the power transmission coil in the opposing direction and shorter than half the length of the power receiving coil in the opposing direction. By setting the length of the portion where the power transmission coil and the power receiving coil overlap with the magnetic core to be less than half the length of the power transmission coil and the power receiving coil in the same direction (the opposing direction), the volume of the magnetic body required for the magnetic core can be reduced, thereby achieving size and weight reduction.

[0041] Second Embodiment Next, a second embodiment will be described with reference to FIGS. 9 to 12. Components that are the same as or equivalent to those shown in FIGS. 1 to 8 are designated by the same reference numerals, and a description thereof will be omitted. The contactless power transfer system is the same as that of the first embodiment, and therefore a description of the entire contactless power transfer system will be omitted. FIG. 9 is a perspective view showing an example of the configuration of a coil unit in the second embodiment. FIG. 9 shows a non-powered state in which the power transmitting coil 21 and the power receiving coil 31 are spaced apart by a certain distance or more. The coil unit 200 includes the power transmitting coil 21, the power receiving coil 31, a magnetic core 50, and a second magnetic core 60, i.e., a second magnetic body. The power transmitting coil 21, the power receiving coil 31, and the magnetic core 50 are the same as those of the first embodiment.

[0042] The second magnetic core 60 is a plate-shaped magnetic body having a thickness in the z-axis direction and extending along the x-axis and y-axis directions. The second magnetic core 60 is disposed in the vicinity of an upper portion of the power receiving coil 31, and the lower surface of the second magnetic core 60 faces at least a portion of one straight portion of the rectangular power receiving coil 31. In the example shown in FIG. 9 , the second magnetic core 60 faces a portion of the upper surface of the straight portion 31a of the power receiving coil 31 in the z-axis direction. In FIG. 9 , the second magnetic core 60 is disposed in the vicinity of the straight portion 31a. As described above, the magnetic core 50 is disposed in the vicinity of a lower portion of the power transmitting coil 21. The magnetic core 50 and the second magnetic core 60 are fixed to the power transmitting coil 21 and the power receiving coil 31, respectively, via intermediate members (not shown).

[0043] When the magnetic core 50 is arranged on one side (below) of one coil (power transmission coil 21), the second magnetic core 60 is arranged on the other side (above) of the other coil (power receiving coil 31). When the magnetic core 50 is arranged above the power receiving coil 31, the second magnetic core 60 is arranged below the power transmitting coil 21. In other words, the second magnetic core 60 is arranged on the other coil opposite to the side facing the one coil.

[0044] 9 shows a configuration example in which the magnetic core 50 is disposed below the power transmission coil 21 and the second magnetic core 60 is disposed above the power receiving coil 31. However, the magnetic core 50 may be disposed near the power receiving coil 31 and the second magnetic core 60 may be disposed near the power transmission coil 21. As described above, since FIG. 9 shows the non-powered state, the through portion 51 of the magnetic core 50 penetrates only the power transmission coil 21 and the intersecting portion 52 intersects only the power transmission coil 21. The second magnetic core 60 is disposed so as not to penetrate or intersect any of the coils. For example, the second magnetic core 60 is disposed parallel to the top surface of the power receiving coil 31.

[0045] FIG. 10 is a side view showing an example of the configuration of a coil unit according to the second embodiment, as viewed from the −y direction. FIG. 10 illustrates a state during power supply, in which the power transmitting coil 21 and the power receiving coil 31 are positioned closer to each other than in the non-power supply state shown in FIG. 9 . That is, the separation distance L* during power supply shown in FIG. 10 is smaller than the separation distance L in FIG. 9 . The magnetic core 50 is similar to that of the first embodiment, and therefore its description is omitted. When viewed from the −y direction, the second magnetic core 60 has a flat plate-like shape extending linearly along the x-axis direction, and its lower surface forms an opposing surface 60a that faces the magnetic core 50 in the z-axis direction. When power is supplied, the second magnetic core 60 is positioned close to both the through portion 51 and the intersection portion 52 of the magnetic core 50. 10 , a gap is provided between the magnetic core 50, more specifically, the upper end surface of the through-hole 51 and the upper end surface of the intersection 52, and the second magnetic core 60, more specifically, the opposing surface 60a, even during power supply. However, the magnetic core 50 and the second magnetic core 60 may be in contact during power supply. Furthermore, the second magnetic core 60 does not need to be entirely flat as long as it is close to both the through-hole 51 and the intersection 52 of the magnetic core 50 during power supply. The second magnetic core 60 may have a bent or curved shape depending on the shapes of the power receiving coil 31 and the magnetic core 50.

[0046] In FIG. 10 , the length L2 of the through portion 51 excluding the thickness of the connecting portion 53 and the length L3 of the intersection portion 52 excluding the thickness of the connecting portion 53 are equal, as in the first embodiment. However, the lengths L2 and L3 may be different. Even when the lengths L2 and L3 are different, it is preferable that the second magnetic core 60 be disposed so as to be in close proximity to or in contact with both the through portion 51 and the intersection portion 52. In addition, in FIG. 10 , the end of the second magnetic core 60 (the end in the x-axis direction in FIG. 10 ) is configured to be close to the end of the magnetic core 50, more specifically, the upper end of the through portion 51 and the upper end of the intersection portion 52. However, these ends do not necessarily need to be close to each other; one end may be close to the center of the other (the portion between one end and the other end of the other). For example, the configuration may be such that the end of the second magnetic core 60 in the -x direction is located directly above the center of the magnetic core 50 in the x-axis direction, or the configuration may be such that the through portion 51 or the intersection portion 52 is located directly below the center of the second magnetic core 60 in the x-axis direction.

[0047] Furthermore, in the width direction (x-axis direction) of the connection portion 53, the length L5 of the portion where the power transmitting coil 21 and the power receiving coil 31 overlap with the magnetic core 50 and the second magnetic core 60 is preferably set to a length less than half the length L4 of the power transmitting coil 21 and the power receiving coil 31 in the x-axis direction. Setting the widths and positions of the magnetic core 50 and the second magnetic core 60 in this manner reduces the volume of the required magnetic material, as in the first embodiment. Also, reducing the volume of the required magnetic material allows for smaller size and weight, as in the first embodiment. The air gap in the magnetic flux path generated when power is transmitted from the power transmitting coil 21 to the power receiving coil 31 is shortened, reducing magnetic resistance and thereby providing the effect of strengthening magnetic coupling, as in the first embodiment.

[0048] It is also possible for the second magnetic core 60 to have the same configuration as the first magnetic core 50, i.e., a through portion, an intersection portion, and a connection portion. The second magnetic core 601 shown in FIG. 11 has an inverted U-shaped cross section, upside down compared to the magnetic core 50, and includes a through portion 61 that penetrates the inside of the power receiving coil 31, an intersection portion 62 that intersects with the power receiving coil 31 on the outside of the power receiving coil 31, and a connection portion 63. The through portion 61, intersection portion 62, and connection portion 63 of the second magnetic core 601 correspond to the through portion 51, intersection portion 52, and connection portion 53 of the magnetic core 50, respectively. When such a second magnetic core 601 is used, the sum of the length of the through portion 51 in the z-axis direction (excluding the thickness of the connection portion 53) and the length of the through portion 61 in the z-axis direction (excluding the thickness of the connection portion 63) corresponds to the length L2 in FIG. 10 . This length is designated as L2* in FIG. 11 . The sum of the length of intersection 52 in the z-axis direction (excluding the thickness of connection portion 53) and the length of intersection 62 in the z-axis direction (excluding the thickness of connection portion 63) corresponds to length L3 in Fig. 10. In Fig. 11, this is represented as length L3*.

[0049] 12 is a plan view showing a configuration example of a coil unit in embodiment 2. As in the example of FIG. 10 , the ends of the second magnetic core 60 (in FIG. 12 , the ends in the x-axis direction and the y-axis direction) and the ends of the magnetic core 50 (the upper ends of the through-portions 51 and the upper ends of the intersection portions 52) are configured to be close to each other when power is supplied, so in FIG. 12 , which is a view from the +z direction, the second magnetic core 60 covers the entire magnetic core 50. However, as described above, the ends of the second magnetic core 60 and the magnetic core 50 do not necessarily have to be close to each other when power is supplied, so the magnetic core 50 may be exposed in the plan view depending on the positional relationship between the magnetic core 50 and the second magnetic core 60.

[0050] According to the second embodiment, the same effect as that of the first embodiment can be obtained. Furthermore, it is possible to increase the amount of magnetic flux interlinking both coils, thereby strengthening the magnetic coupling. More specifically, a second magnetic core is provided in the receiving coil. The second magnetic core is close to the penetration portion and intersection portion of the magnetic core during power supply. Therefore, forming a magnetic flux path through the two magnetic cores increases the amount of magnetic flux interlinking both coils. As a result, it is possible to strengthen the magnetic coupling.

[0051] Embodiment 3. Next, embodiment 3 will be described with reference to FIGS. 13 to 16. Components identical or corresponding to those shown in FIGS. 1 to 12 are designated by the same reference numerals, and their description will be omitted. The contactless power transfer system is similar to that of embodiment 1, and therefore a description of the entire contactless power transfer system will be omitted. FIG. 13 is a perspective view showing an example of the configuration of a coil unit in embodiment 3. FIG. 13 illustrates a non-powered state in which the power transmission coil 21 and the power receiving coil 31 are spaced apart by a certain distance or more. Although not shown in FIG. 13, the power transmission coil 21 and the power receiving coil 31 are also spaced apart by a distance L in the direction of their respective winding axes (z-axis direction). In embodiment 3, the magnetic core 50 is replaced with multiple magnetic cores 50A to 50D. The coil unit 300 includes a power transmission coil 21, a power receiving coil 31, and magnetic cores 50A to 50D. The magnetic cores 50A to 50D are disposed near the straight portions 21a to 21d, respectively. The configuration of the magnetic cores 50A to 50D is the same as that of the magnetic core 50 in embodiment 1. The magnetic cores 50A to 50D are also arranged in the same positions as the magnetic core 50, that is, below the respective straight sections. As described above, FIG. 13 shows the non-powered state, and therefore the through sections of the magnetic cores 50A to 50D only penetrate the power transmission coil 21, and the intersecting sections only intersect with the power transmission coil 21. In the example shown in FIG. 13, a total of four magnetic cores 50 are arranged, one on each straight section of the power transmission coil 21, but it is sufficient if at least two or more magnetic cores 50 are arranged.

[0052] Furthermore, some of the magnetic cores 50 may be disposed near the power receiving coil 31. Although not shown in the drawings, for example, when the magnetic core 50B is disposed near the straight portion 31b of the power receiving coil 31 as the other magnetic core, the magnetic core 50B, i.e., the other magnetic core, is disposed so as to cover a portion of the upper side of the straight portion 31b of the power receiving coil 31. The magnetic core 50B as the other magnetic core includes a second through portion (not shown) that protrudes in the −z direction and penetrates the inside of the power receiving coil 31, a second intersecting portion (not shown) that faces the second through portion and intersects with the power receiving coil 31 on the outside of the power receiving coil 31, and a second connecting portion (not shown) that extends along the x-axis and y-axis directions and connects the second through portion and the second intersecting portion. Note that in the non-powered state, the second through portion penetrates only the power receiving coil 31, and the second intersecting portion intersects only with the power receiving coil 31. During power supply, the other through portion passes through the power receiving coil 31 and the power transmitting coil 21 , and the other intersecting portion intersects with the power receiving coil 31 and the power transmitting coil 21 .

[0053] As described above, it is arbitrary whether each of the magnetic cores 50A to 50D is disposed near the power transmitting coil 21 or the power receiving coil 31. All four may be disposed near the power transmitting coil 21, or all four may be disposed near the power receiving coil 31. Alternatively, some may be disposed near the power transmitting coil 21 and the remaining may be disposed near the power receiving coil 31. That is, in the third embodiment, each of the multiple magnetic cores 50 is disposed near either the power transmitting coil 21 or the power receiving coil 31. Note that the positions and shapes of the magnetic cores 50 (including the other magnetic core) are set so as not to interfere with each other in the non-powered state and during power supply. Specifically, when the magnetic core 50 (or the other magnetic core) is disposed near both the power transmitting coil 21 and the power receiving coil 31, it is conceivable that the magnetic core 50 (or the other magnetic core) is disposed on at most only one of the corresponding straight sections, such as the straight section 21a and the straight section 31a. Furthermore, when magnetic cores 50 are placed on both of the corresponding straight sections, it is possible to adjust the width (length in the x-axis direction) of connection section 53 (or the other connection section) and avoid interference between the connection section and the other connection, and between the intersection section and the other intersection section, even if the separation distance L between the power transmission coil 21 and the power receiving coil 31 is reduced during power supply.

[0054] As described above, the shapes of the power transmitting coil 21 and the power receiving coil 31 are not limited to rectangular. The shapes of both or either of the power transmitting coil 21 and the power receiving coil 31 may be polygonal with N sides (N is any natural number equal to or greater than 3). Even in such cases, the multiple magnetic cores 50 may be arbitrarily assigned to the N straight line portions of the power transmitting coil 21 and the power receiving coil 31. For example, all of the magnetic cores 50 may be arranged in the power transmitting coil 21, or only some of the magnetic cores 50 may be arranged in the power receiving coil 31. Furthermore, even when the power transmitting coil 21 and the power receiving coil 31 are partially or entirely curved, magnetic cores 50 matching the shapes of the power transmitting coil 21 and the power receiving coil 31 may be used.

[0055] FIG. 14 is a side view showing an example of the configuration of a coil unit according to the third embodiment, as viewed from the −y direction. FIG. 14 illustrates a state during power supply, in which the power transmission coil 21 and the power receiving coil 31 are positioned closer to each other than in the non-power supply state shown in FIG. 13 . That is, the separation distance L* during power supply shown in FIG. 14 is smaller than the separation distance L in the non-power supply state. In the third embodiment, the structure and dimensions of each of the magnetic cores 50A to 50D are generally similar to those of the magnetic core 50 according to the first embodiment. For example, focusing on the magnetic core 50A positioned on the +x direction side in the figure, the magnetic core 50A includes a through portion 51A, an intersection portion 52A, and a connection portion 53A. Because the through portion 51A passes through the power transmitting coil 21 and the power receiving coil 31, the length L2 of the through portion 51A in the z-axis direction, excluding the thickness (length in the z-axis direction) of the connection portion 53A, is preferably longer than the distance L1, which is the sum of the thickness of the power transmitting coil 21, the thickness of the power receiving coil 31, and the distance (separation distance L*) between the power transmitting coil 21 and the power receiving coil 31. Similarly, the length L3 of the intersection portion 52A in the z-axis direction, excluding the thickness of the connection portion 53A, is preferably longer than the distance L1.

[0056] In the width direction (x-axis direction) of the connection portion 53A, it is preferable that the length L5 of the portion where the power transmission coil 21 and the power receiving coil 31 overlap with the magnetic core 50A be set to a length less than 1 / 2 of the length L4 of the power transmission coil 21 and the power receiving coil 31 in the x-axis direction.

[0057] The same applies to the magnetic core 50C arranged on the -x-axis side, and therefore the explanation will be omitted. The same applies to the magnetic core 50B arranged in the center in the x-axis direction, except that the width direction of its connection part (not shown) is in the y-axis direction.

[0058] One difference from the first embodiment is that the multiple magnetic cores 50A-50D must be shaped and positioned so as not to interfere with each other. Furthermore, it is desirable that all magnetic cores 50A-50D have the same shape. This minimizes the number of different shapes of the magnetic cores to be manufactured, reducing the cost of manufacturing magnetic cores with different shapes. However, it is not necessary to set the magnetic cores 50A-50D to the same shape; even if they all have different shapes, the effect of strengthening magnetic coupling can be obtained.

[0059] A case where a magnetic core is disposed on each of the corresponding linear portions of the power transmitting coil 21 and the power receiving coil 31 will be described. FIG. 15 is a side view showing a configuration example of a coil unit according to embodiment 3, in which a magnetic core is disposed on each of the corresponding linear portions of the power transmitting coil and the power receiving coil. FIG. 16 is a diagram illustrating the magnetic core and the other magnetic core. In the example shown in FIG. 15, in addition to the example shown in FIG. 14, a second magnetic core 50C* is disposed above the linear portion 31c of the power receiving coil 31. As can be seen from FIG. 13, the linear portion 21c and the linear portion 31c are linear portions that correspond to each other. The magnetic core 50C includes a through portion 51C, an intersection portion 52C, and a connection portion 53C, similar to the magnetic core 50. The other magnetic core 50C* also includes a second through portion 51C*, an intersection portion 52C*, and a connection portion 53C*. 15 , during power supply, the through portion 51C and the other through portion 51C* pass through both the power transmitting coil 21 and the power receiving coil 31. The intersection portion 52C and the other intersection portion 52C* intersect with both the power transmitting coil 21 and the power receiving coil 31.

[0060] However, it is necessary to prevent interference between the through portion 51C and the other through portion 51C*. Therefore, as shown in FIG. 16 , the length L3 in the z-axis direction of the through portion 51C and the intersection portion 52C, excluding the thickness of each connection portion 53C, is longer than the length L3** in the z-axis direction of the other through portion 51C* and the other intersection portion 52C*, excluding the thickness of each connection portion 53C*. Furthermore, the width of the connection portion 53C, excluding the thickness (length in the x-axis direction) of each through portion 51C and the intersection portion 52C, i.e., the length L10 in the x-axis direction, is longer than the width of the other connection portion 53C*, including the thickness (length in the x-axis direction) of each through portion 51C* and the other intersection portion 52C*, i.e., the length L10* in the x-axis direction. Therefore, even when the power transmitting coil 21 and the power receiving coil 31 are close to each other during power supply, the other magnetic core 50C* is configured to be inserted inside the magnetic core 50C. Furthermore, the tip ends (ends in the -z direction) of the other through portion 51C* and the other intersecting portion 52C* do not come into contact with the upper surface of the connecting portion 53C, so there is no interference between the magnetic core 50C and the other magnetic core 50C*.

[0061] According to the third embodiment, the same effects as those of the first embodiment can be obtained. Furthermore, it is possible to further strengthen the magnetic coupling between the power transmitting coil and the power receiving coil during power supply. More specifically, a plurality of magnetic cores are arranged near the power transmitting coil or the power receiving coil. Therefore, there are at least two or more through-holes that penetrate the inside of the power transmitting coil and the power receiving coil during power supply. Furthermore, there are also at least two or more intersections that intersect with the power transmitting coil and the power receiving coil during power supply. As a result, the amount of magnetic flux interlinking both coils is further increased, making it possible to strengthen the magnetic coupling compared to the first embodiment. Furthermore, it is also possible to adjust the strength of the magnetic coupling by adjusting the number of magnetic cores.

[0062] Furthermore, by using multiple magnetic cores, it is possible to suppress misalignment between the power transmitting coil and the power receiving coil during power supply. To suppress misalignment, it is also possible to use a magnetic core that is integrally formed to surround the power transmitting coil and the power receiving coil at multiple locations. In this case, the degree of freedom in layout and design is reduced. In contrast, when multiple independent magnetic cores are used, the positions of the multiple magnetic cores can be changed when the shapes and sizes of the coils differ, ensuring the degree of freedom in design and layout. As described above, the magnetic core to be used can be determined according to the purpose.

[0063] Furthermore, by arbitrarily allocating multiple magnetic cores near the power transmitting coil and the power receiving coil, the amount of magnetic material placed on the power transmitting side and the power receiving side can be adjusted, which makes it possible to realize a configuration in which no magnetic core is placed on the side of equipment where miniaturization and weight reduction are desired.

[0064] Embodiment 4. Next, embodiment 4 will be described with reference to FIGS. 17 and 18. Components identical to or corresponding to those shown in FIGS. 1 to 16 are designated by the same reference numerals, and their description will be omitted. The contactless power transfer system is similar to that of embodiment 1, and therefore a description of the entire contactless power transfer system will be omitted. FIG. 17 is a perspective view showing an example of the configuration of a coil unit in embodiment 4. FIG. 17 illustrates a non-powered state in which the power transmission coil 21 and the power receiving coil 31 are spaced apart by a certain distance or more. Although not shown in FIG. 17, the power transmission coil 21 and the power receiving coil 31 are also spaced apart by a separation distance L in the direction of their respective winding axes (z-axis direction). In embodiment 4, the second magnetic core 60 is replaced with a plurality of second magnetic cores 60A to 60D. The coil unit 400 includes the power transmission coil 21, the power receiving coil 31, magnetic cores 50A to 50D, and second magnetic cores 60A to 60D. The magnetic cores 50A to 50D are the same as those in embodiment 3. As described above, since Fig. 17 shows the non-powered state, the through-portions of the magnetic cores 50A to 50D pass only through the power transmission coil 21, and the intersecting portions of the magnetic cores 50A to 50D intersect only with the power transmission coil 21.

[0065] The second magnetic cores 60A to 60D are disposed near the straight portions 31a to 31d, respectively. The configuration of the second magnetic cores 60A to 60D is similar to that of the second magnetic core 60 in embodiment 2. In the example shown in Fig. 17, one magnetic core is disposed on each straight portion of the power transmitting coil 21, for a total of four, and one second magnetic core 60 is disposed on each straight portion of the power receiving coil 31, for a total of four, but it is sufficient that at least two magnetic cores 50 and at least two second magnetic cores 60 are disposed.

[0066] Furthermore, when some of the magnetic cores 50 are arranged near the power receiving coil 31 as the other magnetic cores, the same may be done for the second magnetic cores. That is, some of the second magnetic cores 60 may be arranged near the power transmitting coil 21 as the other second magnetic cores, corresponding to the other magnetic cores. Although not shown, for example, when magnetic core 50B is arranged near the straight portion 31b of the power receiving coil 31 to serve as the other magnetic core, second magnetic core 60B is arranged near the straight portion 21b of the power transmitting coil 21 in correspondence with magnetic core 50B. In this case, second magnetic core 60B becomes the other second magnetic core. In this case, magnetic core 50B, i.e., the other magnetic core, is arranged to cover a portion of the upper side of the straight portion 31b of the power receiving coil 31, and therefore second magnetic core 60B, which is the other second magnetic core, is arranged below the straight portion 21b.

[0067] As described above, it is arbitrary whether each of the magnetic cores 50A to 50D is disposed near the power transmitting coil 21 or the power receiving coil 31. All four may be disposed near the power transmitting coil 21, or all four may be disposed near the power receiving coil 31. The second magnetic cores 60A to 60D are disposed corresponding to the magnetic cores 50A to 50D, and therefore, depending on the arrangement of the magnetic cores 50A to 50D, all four may be disposed near the power receiving coil 31, or all four may be disposed near the power transmitting coil 21. Also, some may be disposed near the power receiving coil 31, and the rest may be disposed near the power transmitting coil 21. That is, in the fourth embodiment, each of the multiple magnetic cores 50 is disposed near either the power transmitting coil 21 or the power receiving coil 31, and each of the multiple second magnetic cores 60 is disposed near the other coil. The magnetic cores 50 and the second magnetic cores 60 are arranged and shaped so as not to interfere with each other when power is not supplied and when power is supplied.

[0068] In the example shown in Figure 17, the number of magnetic cores 50 and the number of second magnetic cores 60 are four, which is the same, but the number of second magnetic cores 60 may be fewer than the number of magnetic cores 50, and the second magnetic cores 60 may be arranged partially.

[0069] Fig. 18 is a side view showing an example of the configuration of a coil unit according to the fourth embodiment, and is a view of the coil unit 400 viewed from the -y direction. Fig. 18 shows the state during power supply, in which the power transmitting coil 21 and the power receiving coil 31 are arranged closer to each other than in the non-power supply state shown in Fig. 17. In other words, the separation distance L* during power supply shown in Fig. 14 is smaller than the separation distance L in the non-power supply state.

[0070] In the fourth embodiment, the structure and dimensions of each of the magnetic cores 50A to 50D are generally similar to those of the magnetic core 50 in the first embodiment. Furthermore, the structure and dimensions of each of the second magnetic cores 60A to 60D are generally similar to those of the second magnetic core 60 in the second embodiment. For example, focusing on the magnetic core 50A and the second magnetic core 60A arranged on the +x-direction side in the figure, the magnetic core 50A includes a through portion 51A, an intersection portion 52A, and a connection portion 53A. Because the through portion 51A passes through the power transmitting coil 21 and the power receiving coil 31, the length L2 in the z-axis direction of the through portion 51A excluding the thickness (length in the z-axis direction) of the connection portion 53A is preferably longer than the distance L1, which is the sum of the thickness of the power transmitting coil 21, the thickness of the power receiving coil 31, and the distance (separation distance L*) between the power transmitting coil 21 and the power receiving coil 31. Similarly, it is preferable that the length L3 of the intersection 52A in the z-axis direction, excluding the thickness of the connection 53A, is longer than the distance L1.

[0071] In addition, with respect to the width direction (x-axis direction) of the connection portion 53A, it is preferable that the length L5 of the portion where the power transmission coil 21 and the power receiving coil 31 overlap with the magnetic core 50A and the second magnetic core 60A is set to a length less than 1 / 2 of the length L4 of the power transmission coil 21 and the power receiving coil 31 in the x-axis direction.

[0072] When viewed from the -y direction, the second magnetic core 60A has a flat plate-like shape extending linearly along the x-axis direction, with its lower surface forming an opposing surface 60a that faces the magnetic core 50A in the z-axis direction. The second magnetic core 60A is positioned adjacent to both the through-portion 51A and the intersection 52A of the magnetic core 50A during power supply. In FIG. 18 , even during power supply, a gap is provided between the magnetic core 50A, more specifically, the upper end surfaces of the through-portion 51A and the intersection 52A, and the second magnetic core 60A, more specifically, the opposing surface 60a. However, the magnetic core 50A and the second magnetic core 60A may be in contact during power supply. Furthermore, the second magnetic core 60A does not need to be entirely flat, as long as it is adjacent to both the through-portion 51A and the intersection 52A of the magnetic core 50A during power supply. It may also have a bent or curved shape depending on the shape of the receiving coil 31 and the magnetic core 50.

[0073] The same applies to the magnetic core 50C and the second magnetic core 60C arranged on the -x-direction side, and therefore the explanation will be omitted. The magnetic core 50B and the second magnetic core 60B arranged in the center in the x-axis direction differ in that the width direction of their connecting portion (not shown) is in the y-axis direction, but the same can be said about the lengths L4 and L5 described above.

[0074] A difference from the second embodiment is that the multiple magnetic cores 50A-50D and the second magnetic cores 60A-60D must be shaped and positioned so as not to interfere with each other. Furthermore, it is desirable that all of the magnetic cores 50A-50D have the same shape. It is also desirable that all of the second magnetic cores 60A-60D have the same shape. This minimizes the number of different shapes of the magnetic cores and second magnetic cores to be manufactured, thereby reducing the cost of manufacturing magnetic cores with different shapes. However, it is not necessary for the magnetic cores 50A-50D to have the same shape; even if they are all different shapes, the effect of strengthening magnetic coupling can be obtained. Furthermore, it is not necessary for the second magnetic cores 60A-60D to have the same shape; even if they are all different shapes, the effect of strengthening magnetic coupling can be obtained.

[0075] According to the fourth embodiment, the same effects as those of the second embodiment can be achieved. Furthermore, the magnetic coupling between the power transmitting coil and the power receiving coil during power supply can be further strengthened. More specifically, a plurality of magnetic cores are arranged near the power transmitting coil or the power receiving coil, and a plurality of second magnetic cores are arranged near the power receiving coil or the power transmitting coil corresponding to the magnetic cores. Therefore, there are at least two through-holes penetrating the inside of the power transmitting coil and the power receiving coil during power supply. Furthermore, there are at least two intersections where the power transmitting coil and the power receiving coil intersect during power supply, and there are at least two second magnetic cores adjacent to the through-holes and intersections of the magnetic cores during power supply. As a result, the amount of magnetic flux interlinking both coils is further increased, enabling stronger magnetic coupling than in the second embodiment. Furthermore, the strength of the magnetic coupling can be adjusted by adjusting the number of magnetic cores and second magnetic cores.

[0076] Furthermore, there are a plurality of pairs of magnetic cores and second magnetic cores, and each pair is independent of the others, which ensures a degree of freedom in design and layout, similar to the third embodiment.

[0077] Furthermore, by adjusting the arrangement of the multiple magnetic cores and the multiple second magnetic cores, it is possible to adjust the amount of magnetic material arranged on the power transmitting side and the power receiving side. For example, if the second magnetic cores are lighter than the magnetic cores, it is possible to allocate more second magnetic cores to equipment where miniaturization and weight reduction are desired. (Other Modifications)

[0078] In the above-described embodiments, the magnetic core and the second magnetic core are disposed near the straight portions of the rectangular power transmitting coil and power receiving coil, respectively. However, the positions of the magnetic core and the second magnetic core do not necessarily have to be near the straight portions. For example, the magnetic core and the second magnetic core may be disposed near the corners of the rectangular coils. FIG. 19 is a perspective view showing an example in which the magnetic core and the second magnetic core are disposed at the corners of the power transmitting coil and the power receiving coil, respectively. Note that FIG. 19 illustrates a non-powered state in which the power transmitting coil 21 and the power receiving coil 31 are spaced apart by a certain distance or more. While a modification of the second embodiment is used as an example here, similar modifications are possible for the other embodiments described above. The coil unit 201 includes the power transmitting coil 21, the power receiving coil 31, the magnetic core 501, and the second magnetic core 602. The power transmitting coil 21 and the power receiving coil 31 are the same as those in the first embodiment.

[0079] The magnetic core 501 is disposed near a corner connecting the straight portion 21a and the straight portion 21d. The magnetic core 501 includes a through portion 511 that protrudes in the +z direction and penetrates the inside of the power transmission coil 21, an intersection portion 521 that faces the through portion 511 and intersects with the power transmission coil 21 on the outside of the power transmission coil 21, and a connection portion 531 that extends along the x-axis and y-axis directions and connects the through portion 511 and the intersection portion 521. The through portion 511 has a portion that follows the inner surface of the straight portion 21a and a portion that follows the inner surface of the straight portion 21d, and has an L-shaped cross section when viewed from the z-axis direction. The intersection portion 521 has a portion that follows the outer surface of the straight portion 21a and a portion that follows the outer surface of the straight portion 21d, and has an L-shaped cross section when viewed from the z-axis direction. The through portion 511 is shaped to fit along the inside of the corner of the power transmitting coil 21 and is fixed to the inside of the corner. The intersecting portion 521 is shaped to fit along the outside of the corner of the power transmitting coil 21 and is fixed to the outside of the corner.

[0080] Similarly to the through portion 51 in the first embodiment, the through portion 511 passes only through the inside of the power transmitting coil 21 in the non-powered state, and passes through the inside of the power transmitting coil 21 and the power receiving coil 31 during power feeding. Similarly, the intersecting portion 521 intersects only the power transmitting coil 21 in the non-powered state, and intersects the power transmitting coil 21 and the power receiving coil 31 during power feeding.

[0081] The second magnetic core 602 is disposed near the upper corner connecting the straight portion 31a and the straight portion 31d. The second magnetic core 602 is a plate-shaped magnetic body having a thickness in the z-axis direction and extending in the diagonal direction of the power receiving coil 31. The second magnetic core 602 has an end portion facing outward from the power receiving coil 31 and an end portion facing inward from the diagonal direction. The end portion facing inward is provided with a protrusion 602b that protrudes inward from the power receiving coil 31. The end portion facing outward is provided with a protrusion 602c that protrudes outward from the power receiving coil 31. The protrusion 602b has a notch formed from the inside of the power receiving coil 31. As a result, when viewed from below, the protrusion 602b protrudes inward from the power receiving coil 31 as an L-shaped portion, and the lower surface of the protrusion 602b faces the upper end surface of the through portion 511. The protrusion 602c is an isosceles triangular protrusion with the diagonal of the power receiving coil 31 as its center line. When viewed from below, the protrusion 602c is an L-shaped portion that protrudes outward from the power receiving coil 31. As a result, the lower surface of the protrusion 602c faces the upper end surface of the intersection 521. Note that the shapes of the protrusions 602b and 602c described above are merely examples, and it is sufficient that at least a portion of the lower surface of the protrusions 602b and 602c corresponds to the opposing surface 60a in the second embodiment and the like. That is, it is sufficient that at least a portion of the lower surface of the protrusion 602b faces the upper end surface of the through-hole 511, and at least a portion of the lower surface of the protrusion 602c faces the upper end surface of the intersection 521. The rest of the configuration is the same as in the second embodiment. Even when the magnetic core and the second magnetic core are provided at the corners of the power transmitting coil and the power receiving coil as in this modified example, the same effect as in the second embodiment can be obtained.

[0082] Next, an example in which the power transmitting coil and the power receiving coil are not rectangular will be described. FIG. 20 is a perspective view showing an example in which magnetic units are arranged around hexagonal power transmitting and receiving coils. Note that FIG. 20 shows a state during power supply, in which power transmitting coil 211 and power receiving coil 311 are close to each other. Although a modification of embodiment 3 is used as an example here, similar modifications are possible for the other embodiments. Coil unit 301 includes power transmitting coil 211, power receiving coil 311, and magnetic cores 502A to 502C. Power transmitting coil 211 and power receiving coil 311 are each wound around a virtual winding axis (z-axis in FIG. 20 ) along a virtual plane perpendicular to the winding axis (x-y plane in FIG. 20 ). In the power transmitting coil 211, adjacent straight sections, such as straight section 211a and straight section 211b, form angles of 120°, and the entire coil (straight sections 211a to 211f and corners connecting each straight section) forms a regular hexagonal shape. Similarly, in the power receiving coil 311, adjacent straight sections, such as straight section 311a and straight section 311b, form angles of 120°, and the entire coil (straight sections 311a to 311f and corners connecting each straight section) forms a regular hexagonal shape.

[0083] Magnetic cores 502A, 502B, and 502C are disposed near straight portions 211b, 211d, and 211f, respectively. The configuration and arrangement of magnetic cores 502A, 502B, and 502C are the same as those of magnetic core 50 in embodiment 1. Taking magnetic core 502C as an example, magnetic core 502C includes a through portion 512C that protrudes in the +z direction and penetrates the inside of power transmitting coil 211 and power receiving coil 311, an intersection portion 522C that faces through portion 512C and intersects with power transmitting coil 211 and power receiving coil 311 outside power transmitting coil 211 and power receiving coil 311, and a connection portion 532C that extends along the x-axis and y-axis directions and connects through portion 512C and intersection portion 522C. 20 shows the state during power feeding, in which power feeding coil 211 and power receiving coil 311 are close to each other, so through portion 512C passes through both power feeding coil 211 and power receiving coil 311. Also, intersection portion 522C intersects with both power feeding coil 211 and power receiving coil 311. When power feeding coil 211 and power receiving coil 311 are separated by a certain distance or more in the non-power feeding state, through portion 512C passes only through the inside of power feeding coil 211, and intersection portion 522C intersects only with power feeding coil 211.

[0084] 20, a total of three magnetic cores 50 are arranged on a linear portion of the power transmitting coil 211, but there is no limitation on the number of magnetic cores 50 to be arranged. Also, some or all of the magnetic cores 50 may be arranged near the power receiving coil 311 instead of near the power transmitting coil 211.

[0085] 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.

[0086] 10 AC power supply, 21, 211 Power transmission coil, 30 Power receiving resonant circuit, 31, 311 Power receiving coil, 50, 50A to 50D, 501, 502A to 502C Magnetic core, 50C* Other magnetic core, 51, 511, 512C, 51A, 51C, 51C*, 61 Penetration portion, 52, 521, 522C, 52A, 52C, 52C*, 62 Intersection portion, 53, 531, 532C, 53A, 53C, 53C*, 63 Connection portion, 60, 60A to 60D, 601, 602 Second magnetic core, 60a Opposing surface, 100, 200, 201, 300, 301, 400 Coil unit, 1000, 1001 Contactless power supply system, 1100 Power transmitting side device, 1101 power supply rack, 1200 power receiving side device, 1201, 1201A, 1201B module device, L, L* separation distance, L1 distance, L2 to L5, L2*, L3*, L3** length

Claims

1. A coil unit having a transmitting coil and a receiving coil which have parallel winding axes and are separated by a distance in the winding axis direction, which is the direction of the winding axis, and which during power supply, the transmitting coil and the receiving coil are magnetically coupled to transmit AC power from the transmitting coil to the receiving coil, and which comprises a magnetic body which strengthens the magnetic coupling between the transmitting coil and the receiving coil during power supply, wherein when one of the transmitting coil and the receiving coil is designated as one coil and the other is designated as the other coil, the magnetic body includes: a connection portion which faces a part of the one coil in the winding axis direction, a through portion which protrudes from the connection portion in the winding axis direction and penetrates the inside of the one coil, and an intersection portion which protrudes from the connection portion in the winding axis direction and sandwiches the part of the one coil with the through portion, and wherein during power supply, the through portion penetrates the one coil and the other coil, and the intersection portion intersects the one coil and the other coil.

2. A coil unit as described in claim 1, wherein the length of the through portion in the winding axis direction, excluding the thickness of the connection portion, is longer than the sum of the thickness of the one coil, the thickness of the other coil, and the separation distance when power is supplied.

3. A coil unit as described in claim 1 or 2, wherein when the direction perpendicular to the winding axis direction and in which the through portion and the intersection portion face each other is defined as the facing direction, and the direction perpendicular to the winding axis direction and the facing direction is defined as the magnetic material extension direction, in a side view seen from the magnetic material extension direction, the length in the facing direction of the portion where the connection portion and one of the coils overlap in the facing direction is shorter than half the length of the one coil in the facing direction and shorter than half the length of the other coil in the facing direction.

4. A coil unit as described in any one of claims 1 to 3, wherein the other coil has an opposing surface facing the magnetic body in the winding axis direction, and is provided with a second magnetic body that is adjacent to the through portion and the intersection portion when power is supplied.

5. A coil unit according to any one of claims 1 to 4, comprising a plurality of said magnetic bodies.

6. A coil unit as claimed in any one of claims 1 to 5, further comprising a other magnetic body provided on the other coil, the other magnetic body including: a other connection portion facing a part of the other coil in the winding axis direction; a other through portion protruding from the other connection portion in the winding axis direction and penetrating the inside of the other coil; and a other intersection portion protruding from the other connection portion in the winding axis direction and sandwiching the part between the other through portion and the other through portion, and wherein during power supply, the other through portion penetrates the other coil and the one coil, and the intersection portion intersects with the other coil and the one coil.

7. A coil unit according to claim 4, comprising a plurality of said magnetic bodies and a plurality of said second magnetic bodies.

8. A coil unit as described in claim 6, further comprising a second magnetic body on one of the coils, the second magnetic body on the other of the coils having an opposing surface facing the other magnetic body in the direction of the winding axis, and adjacent to the other through-hole and the other intersection when power is supplied.

9. A coil unit according to claim 7, wherein the number of said magnetic bodies is greater than the number of said second magnetic bodies.

10. A coil unit according to claim 8, wherein the number of the other magnetic bodies is greater than the number of the other second magnetic bodies.

11. A contactless power supply system comprising: a coil unit according to any one of claims 1 to 10; a power transmission side device to which the power transmission coil is fixed and which supplies AC power to the power transmission coil; and a power receiving side device to which the power receiving coil is detachably provided.

12. A coil structure having a magnetic body and a coil used for contactless power supply, wherein the magnetic body includes a connection portion facing a part of the coil in a winding axis direction that is the direction of the winding axis of the coil, a through portion protruding from the connection portion in the winding axis direction and penetrating the inside of the coil, and an intersection portion protruding from the connection portion in the winding axis direction and sandwiching the through portion and the part, wherein the coil is a power transmitting coil that magnetically couples with another coil separated from the other coil in the winding axis direction during power supply and transmits power between the other coil via magnetic energy or a power receiving coil to which the power is transmitted, wherein the magnetic body strengthens the magnetic coupling between the coil and the other coil during power supply, wherein the through portion penetrates the inside of the coil and the other coil during power supply, and the intersection portion intersects the coil and the other coil.

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