Coil structure for wireless power supply device

Abstract

In a wireless power supply device, a higher performance coil structure is provided that can further increase the transmission distance and further improve the power transmission efficiency. In the coil structure used in the wireless power supply device, two helical coils (31, 32) are located to the left and right of the solenoid coil (33) (positive and negative sides in the X-axis direction). Near the center of the X-axis length of the magnetic core (11) close to the solenoid coil (33), the coil is positioned higher than the magnetic flux passing through the interior of the magnetic core (11) (positive side in the Z-axis direction). Near the end of the X-axis length of the magnetic core (11) far from the solenoid coil (33), the coil is positioned lower than the magnetic flux passing through the interior of the magnetic core (11) (negative side in the Z-axis direction). That is, in the state of having a step along the vertical (Z-axis direction) near the center and end of the X-axis direction, the coil is wound multiple times from the outside to the inside in a roughly square or roughly circular shape to form a step.

Description

Technical Field

[0001] The present invention relates to the structure of the power supply side coil and / or the power receiving side coil used in a wireless power supply device. Background Technology

[0002] Previously, several known technologies existed for contactless wireless power supply, including electromagnetic induction and magnetic resonance technologies. Electromagnetic induction wireless power supply, for example, is used in mobile phone charging. It involves placing coils vertically, essentially acting as a power transformer. When the power supply coil and the receiving coil are firmly connected, electricity flows.

[0003] However, wireless power supply technology based on electromagnetic induction cannot increase the distance between the power supply coil and the receiving coil. Moreover, even if the positions of the power supply coil and the receiving coil are slightly off or separated, they cannot be charged or supplied, thus posing a problem that makes them difficult to put into practical use.

[0004] Furthermore, wireless power supply technology based on magnetic resonance was developed by universities in the United States around 2006-2007. Compared to electromagnetic induction, it can increase the distance between the power supply coil and the receiving coil, thus reaching a level close to practical application. However, if the distance between the power supply coil and the receiving coil is not constant, transmission is impossible. That is, it has a sensitivity that prevents transmission whether the distance is closer or farther, or at an angle, thus also presenting a problem that hinders its practical application.

[0005] Furthermore, currently, in wireless power supply devices, as a structure to increase transmission distance and improve magnetic flux generation efficiency, there are known coils called "DD coils" or "double D coils" in which two coils are wound into a spiral shape on a magnetic plate (for example, see Patent Document 1). Figure 5 (Patent Document 2, etc.). Moreover, for example, as an electromagnetic coil for transmitting large amounts of power, such as wireless power to electric vehicles, a DD coil (double D coil) is used as the highest performance coil.

[0006] Existing technical documents Patent documents Patent Document 1: Japanese Patent Publication No. 2014-532296 Patent Document 2: Japanese Patent Application Publication No. 2009-164293 Summary of the Invention

[0007] The problem that the invention aims to solve In wireless power supply devices, achieving high power transmission requires generating a large magnetic flux, which must be concentrated in one direction towards the receiving coil. This is to improve efficiency and prevent leakage flux from adversely affecting those nearby. Even a slight increase in coil transmission efficiency (e.g., 1%) can result in a significant difference in heat generation; therefore, even a small improvement in efficiency is desirable. In other words, there is a current expectation for a high-performance coil that can further increase transmission distance and improve power transmission efficiency compared to conventional DD (double-D) coils.

[0008] The present invention was made to solve the aforementioned problems, and aims to provide a higher performance coil structure in a wireless power supply device that can further increase the transmission distance and further improve the power transmission efficiency.

[0009] Solution for solving the problem To achieve the above objectives, the present invention relates to a coil structure for a wireless power supply device, characterized in that the coil structure comprises: a magnetic core in a generally rectangular parallelepiped shape, having a length along its longest side in the X-axis direction, a depth along its second longest side in the Y-axis direction, and a thickness along its shortest side in the Z-axis direction; two helical coils and a solenoid coil, wherein the solenoid coil is a solenoid coil wound multiple times around the magnetic core only near the center of its length in the X-axis direction, and the two helical coils are positioned to the left and right of the solenoid coil (with the solenoid coil as the center of the magnetic core). The center is located on the positive and negative sides of the X-axis direction. Near the center of the X-axis length of the magnetic core, which is close to the solenoid coil, the magnetic core is positioned higher than the magnetic flux passing through the interior of the magnetic core (positive side of the Z-axis direction). Near the end of the X-axis length of the magnetic core, which is far from the solenoid coil, the magnetic core is positioned lower than the magnetic flux passing through the interior of the magnetic core (negative side of the Z-axis direction). That is, in the state of having steps along the vertical (Z-axis direction) near the center and end of the X-axis direction, the magnetic core is wound around the center from the outside to the inside in a roughly square or roughly circular shape to form a step.

[0010] Invention Effects According to the coil structure for the wireless power supply device of the present invention, since each spiral coil has a step and a solenoid coil is wound between the two spiral coils, a longer transmission distance between the power supply coil and the power receiving coil can be ensured, further improving power transmission efficiency and resulting in a higher performance wireless power supply device. Furthermore, because the spiral coils have steps, the performance of the wireless power supply device is not reduced due to the coil leads, and water-cooling pipes for cooling the coil windings can also be configured. Attached Figure Description

[0011] Figure 1 This is a schematic diagram showing four coil structures in a wireless power supply device: three conventional coil structures and one coil structure considered for application.

[0012] Figure 2 It is Figure 1 The diagram shows a comparison of the performance (transmission distance and power transmission efficiency) of the four coil structures.

[0013] Figure 3 This is a schematic diagram illustrating the coil structure (basic type) for a wireless power supply device according to Embodiment 1 of the present invention.

[0014] Figure 4 It means Figure 3 Explanatory diagrams showing the top view, front view, and bottom view of the coil structure used in the wireless power supply device.

[0015] Figure 5 It means to Figure 3 The diagram shows an example of other conceivable variations based on the coil structure used in the wireless power supply device.

[0016] Figure 6 This is a schematic diagram of a simulation model used to compare the performance of the coils of a wireless power supply device.

[0017] Figure 7 This relates to the case of magnetic coupling in the coil structure of the wireless power supply device according to Embodiment 1 of the present invention. Figure 1 (d) is an illustrative diagram comparing the hybrid magnetic coupling cases.

[0018] Figure 8 The relationship between the magnetic flux of the coil structure and the position of the coil in the wireless power supply device of Embodiment 1 of the present invention is as follows: Figure 1 (d) is an explanatory diagram comparing the positional relationship between the hybrid magnetic flux and the coil.

[0019] Figure 9 The lead wires of the spiral coil structure used in the wireless power supply device according to Embodiment 1 of the present invention are different from those of conventional coils. Figure 1 (c) is an explanatory diagram comparing the leads of the spiral coil.

[0020] Figure 10 This is an example of the water pipe configuration used for cooling the coil structure of the wireless power supply device according to Embodiment 1 of the present invention, compared with conventional methods. Figure 1 (c) is an illustrative diagram comparing the coil structures.

[0021] Figure 11This is a diagram showing a specific configuration example of the cooling water pipe in the coil structure of the wireless power supply device according to Embodiment 1 of the present invention.

[0022] Figure 12 Therefore with Figure 5 The same three variations are used to illustrate the coil structure of the wireless power supply device according to Embodiment 2 of the present invention.

[0023] Figure 13 This is an explanatory diagram showing the method of manufacturing a coil structure for a wireless power supply device according to Embodiment 2 of the present invention.

[0024] Figure 14 This is an explanatory diagram showing the winding method of the coil structure for the wireless power supply device according to Embodiment 2 of the present invention.

[0025] Figure 15 This is an explanatory diagram showing the installation method of the magnetic pole plate of the coil structure for the wireless power supply device according to Embodiment 2 of the present invention.

[0026] Figure 16 This is an explanatory diagram showing the positional relationship between the magnetic flux passing through the ferrite core and the coil in the coil structure of each of Embodiments 1 and 2 of the present invention for wireless power supply devices. Detailed Implementation

[0027] The present invention relates to the structure of the power supply side coil and / or the power receiving side coil used in a wireless power supply device, that is, the coil structure for a wireless power supply device.

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0029] First, let's explain wireless power supply technology. Several known technologies exist, including electromagnetic induction and magnetic resonance technologies. Electromagnetic induction wireless power supply technology, for example, is used in charging mobile phones. It involves placing coils vertically; that is, based on the same principle as a transformer, power can only be transmitted when the distance (transmission distance) between the power supply coil and the receiving coil is very short.

[0030] However, the transmission distance of wireless power supply technology based on electromagnetic induction is very short, only a few millimeters. Therefore, it is impossible to increase the distance between the power supply coil and the receiving coil. Moreover, even if the positions of the power supply coil and the receiving coil are slightly off or separated, they cannot charge or supply power. In other words, they have weak resistance to positional deviation, which makes them difficult to put into practical use.

[0031] Furthermore, the transmission distance of wireless power supply technology using magnetic resonance is relatively long, ranging from a few centimeters to several meters. Therefore, compared to electromagnetic induction, it can increase the distance between the power supply coil and the receiving coil, thus reaching a level close to practical application. However, if the distance between the power supply coil and the receiving coil is not kept constant, transmission is impossible. It exhibits sensitivity such as decreased transmission efficiency and inability to transmit the required power regardless of whether the distance is closer or farther, or at an angle. In other words, this method also has weak resistance to positional deviations, thus hindering its practical application.

[0032] In addition, for example, Patent Document 1 discloses a coil in a wireless power supply device for increasing transmission distance and improving magnetic flux generation efficiency, namely a coil called a "DD coil" or "double D coil" in which two coils are wound into a spiral shape on a magnetic plate.

[0033] However, for high-power transmission via wireless power supply devices, a large magnetic flux is required, and this flux needs to be concentrated in one direction towards the receiving coil. This is to improve efficiency and avoid the adverse effects of leakage flux on those nearby. Even a slight increase in coil transmission efficiency (e.g., 1%) can result in a significant difference in heat generation, so even a small improvement in efficiency is desirable. Therefore, there is still a need for a high-performance coil that can further increase transmission distance and improve power transmission efficiency compared to conventional DD (double D) coils.

[0034] Therefore, firstly, the applicant of this application conducted an experiment comparing the transmission distance and power transmission efficiency of conventional coil structures in wireless power supply devices. Figure 1 This is a schematic diagram showing a total of four coil structures in a wireless power supply device: three conventional coil structures and one coil structure considered for application purposes.

[0035] Figure 1 (a) is a coil structure in which a coil 21 (spiral coil 21) is spirally arranged on the upper part of a ferrite core 1, which is a magnetic material. It is a conventional coil structure in wireless power supply devices and is called a "single spiral type". This single spiral type coil structure is used in wireless power supply devices such as those for charging portable information terminals such as smartphones.

[0036] Figure 1 (b) is a coil structure in which the coil 22 (solenoid coil 22) is wound around the ferrite core 1, which is a magnetic body, in a solenoid-like manner. This is also a type of coil structure in wireless power supply devices. This coil structure is called "solenoid type".

[0037] Figure 1(c) is a coil structure in which a spiral coil 23 and a coil 24 (planar spiral coils 23 and 24 forming a double spiral) are arranged in pairs on the upper part of the ferrite core 1, which is a magnetic body. This is also a conventional coil structure in wireless power supply devices, and this coil structure is called "double spiral type". This double spiral type coil structure is the same as, for example, the DD coil (double D coil) disclosed in Patent Document 1.

[0038] and Figure 1 The coil structure of (d) is as follows, and Figure 1 Similarly, in the double-helix type (c), spiral coils 25 and 26 (planar spiral coils 25 and 26 constituting a double helix) are arranged slightly apart on the upper part of the ferrite core 1, which is a magnetic body. A solenoid coil 27 (solenoid coil 27) is arranged between these two coils 25 and 26. Figure 1 (b) Similarly, the ferrite core 1 is wound around the perimeter.

[0039] It should be noted that, Figure 1 (d) is a coil structure that the applicant of this application has considered as an application-oriented coil structure, which is referred to as a "hybrid type".

[0040] That is, regarding Figure 1 These three (a) to (c) are conventional coil structures that are already in use. Figure 1 (d) is the coil structure that the applicant of this application has considered as an application-oriented one.

[0041] Figure 2 It is Figure 1 The diagram shows a comparison of the performance (transmission distance and power transmission efficiency) of the four coil structures. Figure 2 The symbols in the text are relative evaluations, and are marked with ◎, ○, △, and × in that order, starting from excellent performance.

[0042] like Figure 2 As shown, Figure 1 (a) The single-helix coil structure cannot supply power unless the transmission distance is very short (×), but its power transmission efficiency is good (○). Conversely, Figure 1 (b) The solenoid-type coil structure works even over considerable distances (◎), but its power transmission efficiency is not very good (△). On the other hand, Figure 1 (c) The double-helix coil structure is fine even if the transmission distance is relatively long (○), and the power transmission efficiency is also good (○).

[0043] However, in Figure 1In the case of the hybrid coil structure of (d), it becomes possible to achieve a result where even if the transmission distance is quite long (◎), the power transmission efficiency is also quite high (◎).

[0044] Based on these results, it can be seen that if a hybrid coil structure combining the double helix and solenoid types is adopted, a high-performance coil that can increase the transmission distance and further improve the power transmission efficiency compared to conventional DD coils (double D coils) can be provided.

[0045] Furthermore, in this invention, the... Figure 1 (d) shows a further evolution of the coil structure, proposing a method similar to... Figure 1 (c) shows the double-helix coil structure (the conventional DD coil (double D coil)). Figure 1 Compared to the hybrid coil structure shown in (d), a higher-performance coil structure can further increase the transmission distance and further improve the power transmission efficiency.

[0046] Implementation method 1. Figure 3 This is a schematic diagram illustrating the coil structure (basic type) for a wireless power supply device according to Embodiment 1 of the present invention. Figure 3 The schematic diagram shown does not depict the resin winding mold used for winding the coil (see below). Figure 12 Only the ferrite core (magnetic core) and the coil winding, which are the magnetic materials, are shown in the diagram. Furthermore, Figure 4 It means Figure 3 Explanatory diagrams showing the top view, front view, and bottom view of the coil structure used in the wireless power supply device. Figure 4 (b) is from Figure 3 The main view is observed in the direction of arrow A. Figure 4 (a) is a top view taken from directly above. Figure 4 (c) is a bottom view taken from below.

[0047] like Figure 3 , Figure 4 As shown, the coil structure for the wireless power supply device of the present invention involves two spiral coils 31 and 32 (a stepped spiral coil 31 and 32 forming a double helix) that are wound obliquely from the top to the bottom of a ferrite core (magnetic core) 11, which is a magnetic body. The two coils 31 and 32 are arranged in a slightly separated state, and a solenoid coil 33 (sophoid coil 33) is arranged between the two coils 31 and 32 and wound around the ferrite core 11 as an axis.

[0048] More specifically, such as Figure 3As shown, the ferrite core 11 is a roughly cuboid-shaped magnetic body with a length of left and right as its longest side in the X-axis direction, a depth as its second longest side in the Y-axis direction, and a thickness of top and bottom as its shortest side in the Z-axis direction. It should be noted that the X-axis, Y-axis, and Z-axis indicate which direction only... Figure 3 The image shown in the middle is omitted in other figures, but it is also present in other figures. Figure 3 Similarly, define the X-axis, Y-axis, and Z-axis. That is, the descriptions of "up" and "down" are descriptions of whether the Z-axis direction is positive or negative.

[0049] In addition, the word "approximately" in "magnetic body in approximately cuboid shape" means that the corners of the cuboid are slightly rounded or the intersecting edges are not right angles but are oblique, as long as the overall shape looks approximately cuboid, it does not have to be a strict cuboid.

[0050] And, as Figure 3 , Figure 4 As shown, the coil structure for the wireless power supply device according to Embodiment 1 of the present invention includes at least a ferrite core 11, two helical coils 31 and 32, and a solenoid coil 33. It should be noted that in this Embodiment 1, the case where the two helical coils 31 and 32 and the solenoid coil 33 are formed by a single coil winding is described, but the invention is not limited to this.

[0051] Here, the two spiral coils 31 and 32 are spiral coils that form a double helix. Figure 3 , Figure 4 In the two coils 31 and 32, coil 31 is positioned on the left and coil 32 on the right. Furthermore, the left coil 31 is arranged in a stepped configuration along the Z-axis, with its inner side (the side closest to the right coil 32) positioned above the ferrite core 11 (positive side in the Z-axis direction) and its outer side (the side furthest from the right coil 32) positioned below the ferrite core 11 (negative side in the Z-axis direction). Similarly, the right coil 32 is arranged in a stepped configuration along the Z-axis, with its inner side (the side closest to the left coil 31) positioned above the ferrite core 11 (positive side in the Z-axis direction) and its outer side (the side furthest from the left coil 31) positioned near the bottom of the ferrite core 11 (negative side in the Z-axis direction).

[0052] Furthermore, the two stepped spiral coils 31 and 32 are arranged slightly apart along the X-axis. Between the two spiral coils 31 and 32, a solenoid coil 33 is arranged so that it is wound around the ferrite core 11 as an axis, with the coils not overlapping each other in the Y-axis and Z-axis directions.

[0053] The result is that observation Figure 4 (b) It can be seen that the coil structure for the wireless power supply device of the present invention is such that a helical coil 31 is wound obliquely from the upper part near the center of the ferrite core 11 (which is a magnetic body) to the lower part near the left end, and a helical coil 32 is wound obliquely from the upper part near the center of the ferrite core 11 to the lower part near the right end. A solenoid coil 33 is wound around the ferrite core 11 (from top to bottom) between the two coils 31 and 32, with the ferrite core 11 as the axis. Furthermore, the helical coils 31 and 32 are wound multiple times along the Z-axis in a generally square or generally circular shape from the outside to the inside, without overlapping each other. It should be noted that, regarding the winding method of the coils, refer to... Figure 14 This will be discussed later.

[0054] In addition, phrases like "roughly square shape or roughly circular shape" with "roughly" mean that even when the coil is wound layer by layer in a square shape, it will not become a perfect square due to the thickness of the coil, but rather a square shape with slightly rounded corners (roughly square shape). And even when the coil is wound into a circular shape, it does not need to be a perfect circle; it is fine if it is slightly close to an ellipse. That is, as long as it is wound layer by layer from the outside to the inside to form a roughly square shape or roughly circular shape overall, it is acceptable.

[0055] Furthermore, this description illustrates the case where the solenoid coil 33 is wound in multiple rows (multiple columns) only along the X-axis direction, while only one row is wound along the Y and Z axes without overlapping. However, considering the overall size of the coil, the influence of the output voltage, etc., it is also possible to wind two or three layers, etc., with overlapping along the Y and Z axes. That is, the solenoid coil 33 can be "only one row along the X-axis direction, and multiple rows (multiple columns) along the Y and Z axes", or "multiple rows (multiple columns) only along the X-axis direction, and only one row along the Y and Z axes", or "multiple rows (multiple columns) along the X-axis direction and also multiple rows (multiple columns) along the Y and Z axes".

[0056] That is, the solenoid coil 33 only needs to be wound around the ferrite core 11 multiple times near the center of its length in the X-axis direction, and the winding method can be arbitrary. Moreover, the helical coils 31 and 32 can also overlap each other in the Z-axis direction.

[0057] However, there are problems such as insulation damage and easy failure when coils are overlapped in layers, and the transmission distance becomes shorter when the overall thickness of the coil increases. Therefore, both solenoid coil 33 and spiral coils 31 and 32 are preferably wound as shown in the embodiments of the present invention.

[0058] Thus, a solenoid coil 33 is a solenoid coil wound around the ferrite core 11 multiple times only near the center of its length in the X-axis direction. Moreover, two helical coils 31 and 32 are located to the left and right of the solenoid coil 33 (i.e., to the left and right of the solenoid coil 33, on the positive and negative sides in the X-axis direction with the solenoid coil 33 as the center). In the part close to the solenoid coil 33, that is, near the center of the length of the ferrite core 11 in the X-axis direction, it is arranged on the upper part (positive side in the Z-axis direction) of the ferrite core 11, and in the part far from the solenoid coil 33, that is, near the end of the length of the ferrite core 11 in the X-axis direction, it is arranged near the lower part (negative side in the Z-axis direction) of the ferrite core 11. That is, in the state of forming a step along the vertical (Z-axis direction) near the center and end in the X-axis direction, it is wound multiple times from the outside to the inside in a roughly square shape or a roughly circular shape to form a step.

[0059] It should be noted that in this embodiment 1, the two helical coils 31 and 32 are described as being symmetrically arranged with respect to the solenoid coil 33 on its left and right sides (positive and negative sides in the X-axis direction with the solenoid coil 33 as the center). However, it is sufficient that they are arranged on the left and right sides of the solenoid coil 33; they do not need to be completely symmetrical. For example, the helical coils 31 and 32 may differ, such as having different numbers of turns, or being roughly square or roughly circular in shape.

[0060] Furthermore, this description illustrates a coil structure for a wireless power supply device where a coil winding is wound in the following order: one of the two helical coils (here, helical coil 32), the solenoid coil 33, and the other of the two helical coils (here, helical coil 31). However, besides connecting the three coils in series, it is also possible to connect the two helical coils 31 and 32 in parallel and directly connect them to the solenoid coil 33. It should be noted that details regarding the winding method of this coil winding will be explained in Embodiment 2, which will be described later.

[0061] Here, as mentioned earlier, the connection method of the three coils (whether in parallel or series) can be arbitrary, but the direction of the current flowing in the coils is important. Figure 5 As shown, the flow of current causes the magnetic flux generated by the three coils (the two helical coils 31 and 32 and the solenoid coil 33 between them) to reinforce each other. Furthermore, the three coils are bundled and energized in a manner that obeys this law. Thus, as... Figure 5As shown, the coil arranged at the upper part of the ferrite core 11 is wound in such a way that all the current flows in the same direction, and the coil arranged at the lower part of the ferrite core 11 is also wound in such a way that all the current flows in the same direction (however, in the opposite direction to the coil arranged at the upper part).

[0062] Figure 5 It means to Figure 3 The diagram shows an example of other conceivable variations based on the coil structure used in the wireless power supply device. Figure 5 The only difference between the three deformations shown is the length of the ferrite core 11 in the left-right direction (X-axis direction).

[0063] Figure 5 (a-1) and Figure 3 same, Figure 5 (a-2) is Figure 5 (a-1) is a cross-sectional view of the section with a single-dotted line, viewed from the direction of arrow A. Here, the × symbol in the circle on the coil section indicates that the direction of the current flowing in the coil is the same as that of arrow A (in...). Figure 5 In the example of (a-2), from near to deep), the ● symbol in ○ indicates that the direction of the current flowing in the coil is opposite to the direction of arrow A (in Figure 5 In the example of (a-2), the direction from the depths toward the foreground.

[0064] In addition, Figure 5 In (a-2), the magnetic flux (magnetic lines of force) in this coil structure is represented by dashed arrows. As for the arrangement of the coil relative to the ferrite core 11 to form such a ring-shaped magnetic flux, the coil disposed in the upper part of the ferrite core 11 needs to be wound in such a way that the current flows entirely in the same direction, and the coil disposed in the lower part of the ferrite core 11 also needs to be wound in such a way that the current flows entirely in the same direction (however, in the opposite direction to the coil disposed in the upper part).

[0065] and, Figure 5 (b-1) and Figure 5 (c-1) and Figure 5 (a-1) differs from it only slightly in structure. Figure 5 (b-2) is Figure 5 (b-1) is a cross-sectional view of the section with a single dotted line, viewed from the direction of arrow A. Figure 5 (c-2) is Figure 5 (c-1) is a cross-sectional view of the section with a single dashed line, viewed from the direction of arrow A.

[0066] like Figure 5 As shown, Figure 5 The length of the ferrite core 11 in the left-right direction (X-axis direction) is greater than that in (b-1). Figure 5 The ferrite core 11 of (a-1) is slightly shorter (see reference). Figure 5 (b-2)). Moreover, Figure 5 The length of the ferrite core 11 in the left-right direction (X-axis direction) is greater than that of (c-1). Figure 5 The ferrite core 11 of (b-1) is slightly shorter (see reference). Figure 5 (c-2)).

[0067] Here, regarding and Figure 1 (c) shows the double-helix coil structure (the conventional DD coil (double D coil)). Figure 1 Compared to the hybrid coil structure shown in (d), Embodiment 1 of the present invention... Figures 3 to 5 The coil structure used in the wireless power supply device shown can extend the transmission distance and improve the power transmission efficiency.

[0068] In wireless power supply devices, the transmission distance between the power supply coil and the receiving coil can be extended because of a large magnetic coupling coefficient k, and the transmission efficiency is high because of a high Q value, which represents the quality factor of the coil. That is, the product of the magnetic coupling coefficient k and the quality factor Q of the coil (k×Q) becomes the performance index of the coil.

[0069] Figure 6 This is a schematic diagram of a simulation model used to compare the performance of coils in a wireless power supply device. It should be noted that, when using... Figure 6 In the actual experiments and simulations conducted using the simulation model shown, copper is used as the material for the coil, and soft magnetic material, namely soft magnetic ferrite, is used as the material for the ferrite core (magnetic body). However, at low frequencies (below 10kHz, etc.), silicon steel plates, iron-based microcrystalline plates, iron-based amorphous alloy plates, etc., can be used.

[0070] Figure 6 (a) is Figure 1 (d) shows a variation of the hybrid coil structure, and Figure 1 (d) In comparison, a ferrite core 10 with a slightly shorter depth direction (Y-axis direction) is used. Furthermore, the length of this ferrite core 10 in the left-right direction (X-axis direction) is 300 mm, the thickness of the ferrite core 10 in the Z-axis direction is 10 mm, the frequency is 50 kHz, the wire diameter of the coil is 3.83 mm, the two sets of facing helical coils 25 and 26 have 8 turns each and a length of 2.79 m, and the solenoid coil 27 has 5 turns each and a length of 0.877 m.

[0071] on the other hand, Figure 6 (b) is Figure 3 and Figure 5(a-1) shows the coil structure of Embodiment 1 of the present invention. The length of the ferrite core 11 in the left-right direction (X-axis direction) is 300 mm, the thickness of the ferrite core 11 in the Z-axis direction is 10 mm, the frequency is 50 kHz, the wire diameter of the coil is 3.83 mm, the solenoid coil 33 has 5 turns and a length of 0.877 m, and the two sets of facing spiral coils 31 and 32 have 8 turns each. Up to this point, it is consistent with... Figure 6 The situation is the same as shown in (a), but the lengths of the two sets of spiral coils 31 and 32 are 3.17m. This is because, since they are stepped spiral coils 31 and 32, they are longer than... Figure 6 The reason why the lengths of the spiral coils 25 and 26 shown in (a) are longer.

[0072] Here, with the voltage on the power supply side set as V1, the voltage on the power receiving side set as V2, the number of turns of the coil on the power supply side set as N1, and the number of turns of the coil on the power receiving side set as N2, the magnetic coupling coefficient k can be expressed by the formula k = (V2 / V1) × (N1 / N2). A simulation was performed by substituting the values ​​into this formula.

[0073] As a result, in Figure 6 In the case of the coil structure shown in (a), the magnetic coupling coefficient k = 0.187, the coil quality factor Q = 1090, and k × Q = 204. On the other hand, in Figure 6 In the case of the coil structure shown in (b), the magnetic coupling coefficient k = 0.191, the quality factor Q of the coil = 1529, and k × Q = 292. That is, calculations also confirm that the coil structure of Embodiment 1 of the present invention can ensure a longer transmission distance between the power supply coil and the power receiving coil, further improving the power transmission efficiency, thereby obtaining a higher performance wireless power supply device.

[0074] in addition, Figure 6 (c) is Figure 6 (a) shows a variation of the hybrid coil structure, and Figure 6 (a) In comparison, the length of the ferrite core 10 in the left-right direction (X-axis direction) is slightly shorter. Here, Figure 6 (c) The ferrite core 10 shown has a length of 270 mm in the left-right direction (X-axis direction), a thickness of 10 mm in the Z-axis direction, a frequency of 50 kHz, a wire diameter of 3.83 mm, two sets of facing helical coils 25 and 26 with 8 turns each and a length of 2.79 m, and a solenoid coil 27 with 5 turns and a length of 0.877 m. That is, with... Figure 6 (a) is the same except for the length of the ferrite core 10 in the left and right directions.

[0075] on the other hand, Figure 6 (d) is Figure 5(b-1) shows the coil structure of Embodiment 1 of the present invention, in which the length of the ferrite core 11 in the left-right direction (X-axis direction) is 270 mm. Furthermore, the thickness of the ferrite core 11 in the Z-axis direction is 10 mm, the frequency is 50 kHz, the wire diameter of the coil is 3.83 mm, the solenoid coil 33 has 5 turns and a length of 0.877 m, and the two sets of facing helical coils 31 and 32 have 8 turns each. Up to this point, it is consistent with... Figure 6 The situation is the same as shown in (c), but the lengths of the two sets of spiral coils 31 and 32 are 3.17m. That is, compared with... Figure 6 (c) is the same except for the length of the ferrite core 11 in the left and right directions.

[0076] Furthermore, in Figure 6 In the case of the coil structure shown in (c), the magnetic coupling coefficient k = 0.184, the coil quality factor Q = 1088, and k × Q = 201. On the other hand, in Figure 6 In the case of the coil structure shown in (d), the magnetic coupling coefficient k = 0.184, the coil quality factor Q = 1276, and k × Q = 235. In this case, calculations also confirm that the coil structure of Embodiment 1 of the present invention can achieve a higher performance wireless power supply device.

[0077] Thus, for those who used Figure 5 The modified coil structure shown, where the length of the ferrite core 11 in the left-right direction (X-axis direction) is shortened by cutting the two ends of the ferrite core 11 in the X-axis direction, was also simulated and tested. The transmission distance and power transmission efficiency were confirmed, and very high performance was demonstrated for these structures. It was also confirmed that even higher performance can be achieved by adjusting the length of the ferrite core in the left-right direction (X-axis direction).

[0078] It should be noted that these experiments and simulations not only confirmed higher performance when both the power supply coil and the power receiving coil of the wireless power supply device were coil structures of the wireless power supply device according to Embodiment 1 of the present invention, but also when only either the power supply coil or the power receiving coil was a coil structure of the wireless power supply device according to Embodiment 1 of the present invention.

[0079] However, when both the power supply coil and the power receiving coil are coil structures for the wireless power supply device according to Embodiment 1 of the present invention, not only can higher performance be obtained, but it is also advantageous in terms of magnetic coupling.

[0080] Here, the magnetic coupling of the coil structure used in the wireless power supply device will be explained in conjunction with... Figure 1 (c) shows the double-helix coil structure (the conventional DD coil (double D coil)). Figure 1Compared to the hybrid coil structure shown in (d), the embodiment 1 of the present invention... Figures 3 to 5 The coil structure shown in the wireless power supply device has advantages when used for both the power supply coil and the receiving coil.

[0081] Figure 7 This relates to the case of magnetic coupling in the coil structure of the wireless power supply device according to Embodiment 1 of the present invention. Figure 1 (d) is an illustrative diagram comparing the hybrid magnetic coupling cases. Figure 7 (a) indicates that it is configured with Figure 1 (d) shows an example of a hybrid type with both a power supply coil and a power receiving coil, corresponding to... Figure 6 (a), but shows the state where the positions of the two coils are offset. In this case, the visible portion of the surface (upper surface) of the ferrite core 1 (hereinafter referred to as the "magnetic pole") can be used for magnetic coupling, but as Figure 7 As shown in (a), only the area near the center of each coil in the left-right direction (the length direction of ferrite core 1) can be used as a magnetic pole, and the magnetic flux loop generated between the two coils becomes Figure 7 (a) shows the area indicated by the dashed arrow.

[0082] on the other hand, Figure 7 (b) is a diagram showing an example of a coil structure for a wireless power supply device according to Embodiment 1 of the present invention, which includes both a power supply coil and a power receiving coil. However, it differs from... Figure 7 (a) Similarly, the state of positional deviation of the two coils is shown, corresponding to Figure 6 (b). The Figure 7 (a) and (b) correspond to Figure 6 (a) and (b), therefore it is possible to observe Figure 6 (a) and (b) are easier to understand, but regarding the portion of the ferrite core 11 visible from the surface (top surface) of each coil—the magnetic poles—(b) is longer along the length direction (X-axis) of the coil than (a). In this case, the length that allows for positional deviation in the length direction (X-axis) of the two coils becomes longer, therefore, if the magnetic poles are extended, the length that allows for positional deviation also becomes longer. That is, as... Figure 7 (b) The dotted arrow indicates that the flux loop can be used for magnetic coupling up to the end of the ferrite core 11 along the length direction (X-axis direction), thus having the advantage of strong resistance to coil position deviation.

[0083] Furthermore, from the viewpoint of the relationship between the direction of magnetic flux and the configuration of the coil, it will be explained that the coil structure for the wireless power supply device of Embodiment 1 of the present invention is more resistant to transmission distance and positional deviation than conventional methods.

[0084] Figure 8 The relationship between the magnetic flux of the coil structure and the position of the coil in the wireless power supply device of Embodiment 1 of the present invention is as follows: Figure 1 (d) is an explanatory diagram comparing the positional relationship between the hybrid magnetic flux and the coil.

[0085] Figure 8 (a) and Figure 5 (a-2) Similarly, using Figure 5 (a-1) is represented by a cross-sectional view of the section with the single-dotted line, viewed from the direction of arrow A. Figure 1 (d) shows the positional relationship between the magnetic flux and the coil in the hybrid coil structure. Here, the arrows shown by the dashed lines represent the magnetic flux, and the coils marked with ● in the circles at both ends, i.e., the spiral coils in which the current flows from the depth in the figure toward the foreground, are all positioned on the upper side than the magnetic flux (arrows shown by the thick dashed lines) passing through the ferrite core 1, i.e., on the positive side in the Z-axis direction.

[0086] on the other hand, Figure 8 (b) and Figure 5 (a-2) Similarly, in the coil structure for the wireless power supply device according to Embodiment 1 of the present invention, the following is used: Figure 5 The cross-sectional view of the dashed section in (a-1), viewed from the direction of arrow A, represents the positional relationship between the magnetic flux and the coil. Here, with... Figure 8 (a) Similarly, the arrows shown by the dashed lines represent magnetic flux, but in Figure 8 In (b), the coils marked with ● in the ○ at both ends, that is, the spiral coils in which the current flows from the depth in the figure toward the front, are all positioned on the lower side than the magnetic flux (arrow shown by the thick dashed line) passing through the ferrite core 11, that is, on the negative side in the Z-axis direction.

[0087] And, will Figure 8 (a) and Figure 8 (b) In comparison, based on the difference in the magnitude of the magnetic flux (magnetic lines of force) indicated by the dashed arrows, it can be seen that in Figure 8 (a) In such a coil configuration, the magnetic flux outlet (pole) is narrowed due to the obstruction of the helical coil itself, but through, as Figure 8 (b) By positioning the coils at both ends of the spiral coil at a position lower than the magnetic flux (arrows shown by thick dashed lines) passing through the ferrite core 11 (negative side in the Z-axis direction), the outlet (magnetic pole) of the magnetic flux can be widened, thus having the advantages of resisting the transmission distance of the two coils and increasing positional deviation.

[0088] That is, in the foregoing description, it was explained that the two helical coils 31 and 32 are located to the left and right of the solenoid coil 33 (i.e., on the positive and negative sides of the X-axis with the solenoid coil 33 as the center). In the part close to the solenoid coil 33, that is, near the center of the length of the ferrite core 11 in the X-axis direction, they are arranged on the upper part of the ferrite core 11 (positive side of the Z-axis direction), and in the part far from the solenoid coil 33, that is, near the end of the length of the ferrite core 11 in the X-axis direction, they are arranged near the lower part of the ferrite core 11 (negative side of the Z-axis direction). In other words, in the state of having a step along the vertical (Z-axis direction) near the center and end of the X-axis direction, they are wound in a generally square or generally circular shape multiple times from the outside to the inside to form a step. However, the following description more clearly describes the characteristics of this step.

[0089] Two helical coils 31 and 32 are located to the left and right of the solenoid coil 33 (on the positive and negative sides of the X-axis with the solenoid coil 33 as the center). Near the center of the ferrite core 11 in the X-axis direction, the coils are positioned higher than the magnetic flux passing through the ferrite core 11 (positive side of the Z-axis direction). Far from the solenoid coil 33, near the end of the ferrite core 11 in the X-axis direction, the coils are positioned lower than the magnetic flux passing through the ferrite core 11 (negative side of the Z-axis direction). In other words, the coils are wound in a generally square or generally circular shape to form a stepped structure, with steps along the vertical (Z-axis direction) near the center and end of the X-axis.

[0090] Additionally, regarding the leads of helical coils 31 and 32, and... Figure 1 (c) shows the double-helix coil structure (the conventional DD coil (double D coil)). Figure 1 Compared to the hybrid coil structure shown in (d), Embodiment 1 of the present invention... Figures 3 to 5 The coil structure used in the wireless power supply device shown can lead out the wire without shortening the transmission distance, which will be explained below.

[0091] exist Figure 1 (c) shows the double-helix coil structure (the conventional DD coil (double D coil)). Figure 1In the case of the hybrid coil structure shown in (d), since two helical coils (23 and 24, or 25 and 26) are wound on the upper part (positive side of the Z-axis direction) of the ferrite core 1, which is a magnetic body, that is, two planar helical coils (23 and 24, or 25 and 26) are arranged on the upper part (positive side of the Z-axis direction) of the ferrite core 1, as the wires leading these coil windings to the outside, it is necessary to pass through the helical coils above them, which increases the overall thickness, or to pass between the helical coils in order to keep the overall thickness unchanged. This requires labor and time to divide the ferrite core or study the winding method of the coils.

[0092] However, if it is the invention of this application Figures 3 to 5 The coil structure for the wireless power supply device shown uses the thickness of the ferrite core 11 in the Z-axis direction to lead out the stepped spiral coils 31 and 32 to the outside. It does not require increasing the overall thickness of the coil structure or studying the coil winding method. Therefore, it can lead out the coil winding to the outside without spending labor and time, without shortening the transmission distance.

[0093] Figure 9 The lead wires of the spiral coil structure used in the wireless power supply device according to Embodiment 1 of the present invention are different from those of conventional coils. Figure 1 (c) is an explanatory diagram comparing the leads of the coil in the double-helix coil structure shown. Figure 9 (a) is Figure 1 (c) is a front-view view of a cross-sectional view near the center of the conventional double-helix coil structure along the Y-axis. Figure 9 (b) is for the purpose of... Figure 9 (a) Comparison, from this Figure 3 and Figure 5 (a-1) is a front-view view of the coil structure near the center in the Y direction, omitting the state of the solenoid coil 33. Figure 5 The cross-section of (a-1) with a single-dotted line, viewed from the direction of arrow A, omits only the diagram of solenoid coil 33.

[0094] like Figure 9 As shown in (a), in the case of the conventional double-helix coil structure, since there are two helical coils 23 and 24 wound on the upper part (positive side of the Z-axis direction) of the ferrite core 1 which is a magnetic body, the lead wires 41 and 42 that lead these coil windings to the outside pass through the upper part (positive side of the Z-axis direction) of the helical coils 23 and 24.

[0095] For example, if the outer diameter of the winding is 10mm and there are no leads 41 and 42, and the transmission distance is 10cm (=100mm), then in Figure 9 In case (a), the lead wire will inevitably overlap with the windings of helical coils 23 and 24, thus shortening the transmission distance by the amount of the winding's outer diameter. In this example, the transmission distance becomes 100mm - (winding outer diameter 10mm + winding outer diameter 10mm) = 80mm, meaning 10cm becomes 8cm, which has a significant impact. Thus, the overlap of the lead wire with the windings of helical coils 23 and 24 increases the overall thickness of the coil structure, resulting in the disadvantage of shortened transmission distance.

[0096] On the other hand, such as Figure 9 As shown in (b), in the case of the coil structure for the wireless power supply device according to Embodiment 1 of the present invention, it is a structure in which two stepped spiral coils 31, 32 are wound obliquely near the upper part (positive side in the Z-axis direction) and lower part (negative side in the Z-axis direction) of the ferrite core 11. Therefore, the lead wires 51, 52 that lead these coil windings to the outside can use the thickness portion of the ferrite core 11 in the Z-axis direction. As a result, even if the lead wires are led out from the coil windings, the overall thickness of the coil structure does not change. Therefore, it has the advantage of being able to lead out the wires without shortening the transmission distance, that is, being able to maintain a constant long transmission distance.

[0097] Furthermore, regarding the cooling of the coil windings in the coil structure used in wireless power supply devices, and Figure 1 (c) shows the double-helix coil structure (the conventional DD coil (double D coil)). Figure 1 Compared to the hybrid coil structure shown in (d), Embodiment 1 of the present invention... Figures 3 to 5 The coil structure used in the wireless power supply device shown is superior, and this will be explained below.

[0098] In actual operation (continuous operation), the coil windings need to be cooled by water or air cooling, but in the current... Figure 1 (c) shows the double-helix coil structure (the conventional DD coil (double D coil)). Figure 1 In the hybrid coil structure shown in (d), cooling the coil windings is inherently difficult. Because the ferrite core has very poor thermal conductivity, even if the ferrite core is cooled, the coil windings will not cool. Therefore, direct cooling of the coil windings is necessary. Figure 1 (c) Figure 1 In the conventional coil structure shown in (d), there is no method to directly approach the coil winding.

[0099] Figure 10 This is an example of the water pipe configuration for cooling the coil structure of the wireless power supply device according to Embodiment 1 of the present invention, compared with conventional methods. Figure 1 (c) is an illustrative diagram comparing the coil structures. Figure 10 (a) is about Figure 1 (c) shows an example of a double-helix coil structure with a power supply side coil and a power receiving side coil. However, the helical coils 23 and 24 cannot be accessed from the inside of the ferrite core 1. Furthermore, since the sides of the helical coils 23 and 24 are the transmission space, the presence of cooling water pipes would result in a substantial reduction in the transmission distance. Therefore, cooling water pipes cannot be installed.

[0100] on the other hand, Figure 10 (b) is a diagram showing an example of a coil structure for a wireless power supply device according to Embodiment 1 of the present invention, which includes a power supply coil and a power receiving coil. Figure 10 The lower coil (power receiving coil) in (b) is indicated by the thick line for water cooling tube 61 (61-1, 61-2, 61-3).

[0101] In the case of the coil structure for the wireless power supply device according to Embodiment 1 of the present invention, such as Figure 10 As shown in (b), the spiral coils 31 and 32 have steps, which allows cooling water pipes to be installed at the positions of the water-cooling pipes 61-1, 61-2, and 61-3 shown in thick lines. It should be noted that the dotted part of the thick lines represents the part that passes through the inside and is not visible.

[0102] Figure 11 This is a diagram showing a specific configuration example of the cooling water pipe in the coil structure of the wireless power supply device according to Embodiment 1 of the present invention. Figure 11 (a) is a view of either the power supply coil or the power receiving coil as seen from the surface side (top surface side). Figure 11 (b) is a view from the inside (bottom side). The thick line represents the water-cooled pipe 61, and the arrows indicate the direction in which the cold water flows through it. It should be noted that in this figure, the dashed part of the thick line also represents the part that passes through the inside and is not visible.

[0103] In addition, the specific winding method of the coil and the lead wires (lead-out method) of the coil winding will be described later. However, since heat is difficult to dissipate when the coil winding is bundled, as mentioned above, the case where the coil winding is not bundled but wound in a row will be explained here.

[0104] Furthermore, the coil structure for the wireless power supply device according to Embodiment 1 of the present invention, such as Figure 10 , Figure 11 As shown, it has the advantage of being able to cool the coil winding by configuring a water-cooling pipe 61 for cooling the coil winding.

[0105] As described above, the coil structure for the wireless power supply device according to Embodiment 1 of the present invention, since each spiral coil 31, 32 has a stepped structure and a solenoid coil 33 is wound between these two spiral coils 31, 32, can maintain a longer transmission distance between the power supply side coil and the power receiving side coil, further improving power transmission efficiency and resulting in a higher performance wireless power supply device. Furthermore, since the spiral coils 31, 32 have steps, the performance of the wireless power supply device will not be reduced due to the coil leads. In addition, water-cooling pipes for cooling the coil windings can be configured.

[0106] Implementation method 2. As in Implementation 1 Figure 5 As shown, the length of the ferrite core (magnetic core) in the left-right direction (X-axis direction) can vary in various ways, and regardless of the structure, very high performance (long transmission distance and high power transmission efficiency) has been confirmed. Furthermore, it has been confirmed that even higher performance can be achieved by adjusting the length of the ferrite core in the left-right direction (X-axis direction).

[0107] However, without actual experimentation, it's impossible to determine the optimal ferrite core length (length along the X-axis) for achieving the best performance. Therefore, the choice of core length (length along the X-axis) for the helical coils 31 and 32 could not be confirmed until the desired length was achieved. Figure 5 Which ferrite core shown in (a-1), (b-1), and (c-1) is better?

[0108] Here, we will explain the adjustment of the resonant frequency, which is crucial in wireless power supply devices. Due to variations in the characteristics of ferrite materials and capacitors, it is difficult to adjust the resonant frequency of the resonant circuits (power supply side resonant circuit, power receiving side resonant circuit) to a specified value. Methods for adjusting the resonant frequency include adjusting the number of turns of the coils (power supply side coil, power receiving side coil) and adjusting the electrostatic capacitance of the capacitors. However, adjusting the number of turns of the coils is difficult in practical applications because unwinding or adding windings is required after the coil windings are completed. Furthermore, even when adjusting the electrostatic capacitance of the capacitors, it is difficult to adjust the capacitors themselves because they only have a standard electrostatic capacitance.

[0109] As its solution, such as Figure 5 As in (a-1), (b-1), and (c-1), the resonant frequency can be changed by using ferrite cores of different lengths in the left-right direction (X-axis direction). However, as mentioned before, after the coil winding is completed, it is difficult to adjust even if it is found that a slightly longer or slightly shorter length is better.

[0110] Therefore, it is thought that it is possible to do so Figure 12As shown in the example Figure 5 A ferrite base (magnetic base) 12 of the same length (length in the X-axis direction) as the ferrite core (magnetic core) 11 shown in (c-1) is fitted with magnetic pole plates 13. That is, in this embodiment 2, the ferrite core 11 is composed of a ferrite base 12 of approximately the same shape as the ferrite core 11 and two magnetic pole plates 13 that can be mounted on the ferrite base 12. Furthermore, in the following description, it is assumed that... Figure 12 The thickness of the two magnetic pole plates 13 is thinner than the thickness (Z-axis thickness) of the ferrite base 12.

[0111] Figure 12 The coil structure for the wireless power supply device according to Embodiment 2 of the present invention is combined with... Figure 5 The diagrams show the same three variations. It should be noted that, for ease of explanation, the coil windings (helical coils 31, 32 and solenoid coil 33) are not shown here; only the winding dies 81, 82, 71, the ferrite base 12, and the magnetic pole plate 13 for each coil are shown. It should be noted that regarding these winding dies 81, 82, 71, in... Figure 13 This will be discussed later.

[0112] exist Figure 12 In any of (a), (b), and (c), the length of the ferrite base 12 in the left-right direction (X-axis direction) is as follows: Figure 5 (c-1) and (c-2) use the shortest length, but a magnetic pole plate 13 of different length (length in the X-axis direction) is installed on the upper part (positive side in the Z-axis direction) of the ferrite base 12.

[0113] That is, in Figure 12 (a) When the ferrite base 12 is aligned with the two magnetic pole plates 13, so as to... Figure 5 Two magnetic pole plates 13 are mounted with the same length in the left-right direction (X-axis direction) of the ferrite core 11 in (a-1) and (a-2). Figure 12 (b) When the ferrite base 12 is aligned with the two magnetic pole plates 13, it is in conjunction with... Figure 5 Two magnetic pole plates 13 are mounted with the same length in the left-right direction (X-axis direction) of the ferrite core 11 in (b-1) and (b-2). Figure 12 (c) When the ferrite base 12 is aligned with the two magnetic pole plates 13, so as to... Figure 5 Two magnetic pole plates 13 are mounted with the same length in the left-right direction (X-axis direction) of the ferrite core 11 of (c-1) and (c-2).

[0114] In addition, Figure 12In each of (a), (b), and (c), two magnetic pole plates are installed corresponding to the two helical coils 31 and 32, respectively, on the upper part of the ferrite base 12 (the positive side in the Z-axis direction), and can be installed after the helical coils 31 and 32 are wound. Furthermore, in this… Figure 12 In the example shown, three different sizes of magnetic pole plates 13 are prepared, differing only in their length along the X-axis. These pole plates 13, mounted on the ferrite base 12, can be replaced with a suitable size from among the three. It should be noted that in this… Figure 12 In the examples shown in (a), (b), and (c), the two magnetic pole plates 13 are the same size, but the two magnetic pole plates can sometimes be different sizes (not symmetrical), so they do not have to be the same size.

[0115] It should be noted that, here, in the context of... Figure 12 The three types of magnetic pole plates 13 shown in (a), (b), and (c) have been used as examples for explanation. However, the magnetic pole plates 13 are not limited to three types. As long as multiple magnetic pole plates are prepared, with the only difference being their length along the X-axis, the magnetic pole plates 13 installed on the ferrite base 12 can be replaced with magnetic pole plates of suitable size from among these multiple types, thereby adjusting the resonant frequency. Moreover, since the magnetic pole plates can be adjusted by simple cutting, it is not necessary to prepare multiple types in advance; it is sufficient to install magnetic pole plates 13 of different sizes onto the ferrite base 12.

[0116] Furthermore, although the illustration is omitted, the two magnetic pole plates 13 can be installed not on the upper part (positive side in the Z-axis direction) of the ferrite base 12, but on the left and right ends (positive and negative end faces in the X-axis direction). In this case, two magnetic pole plates are installed corresponding to the two helical coils 31 and 32 respectively, and can be installed after the helical coils 31 and 32 are wound around the left and right ends (positive and negative end faces in the X-axis direction) of the ferrite base 12. It should be noted that in this case, the two magnetic pole plates 13 do not need to be the same size.

[0117] As described above, in Embodiment 1, experiments were conducted using a ferrite core 11 whose length in the left-right direction (X-axis direction) was shortened by cutting off both ends of the ferrite core 11 in the X-axis direction. The transmission distance and power transmission efficiency were confirmed, and these structures were found to have very high performance. In Embodiment 2, experiments were conducted by installing magnetic pole plates 13 with different lengths only in the left-right direction (X-axis direction) on the ferrite base 12. By changing the length of the installed magnetic pole plates 13, the transmission distance and power transmission efficiency were confirmed, and similarly to Embodiment 1, very high performance was confirmed. Furthermore, it was confirmed that by adjusting the length of the magnetic pole plates 13 installed on the upper part (positive side in the Z-axis direction) or the left and right ends (positive and negative end faces in the X-axis direction) of the ferrite base 12 in the left-right direction (X-axis direction), even higher performance can be achieved.

[0118] Furthermore, in the case of the coil structure shown in Embodiment 2, the magnetic pole plates 13 can be installed after the coil windings (helical coils 31, 32, and solenoid coil 33) are wound around the ferrite base 12. Therefore, it has the advantage of being able to install magnetic pole plates 13 of optimal length to adjust the resonant frequency according to variations in the characteristics of the ferrite core composed of the ferrite base 12 and the two magnetic pole plates 13. That is, it is precisely the coil structure of this embodiment that allows for the installation of magnetic pole plates 13 of different sizes (length in the X-axis direction) to adjust the resonant frequency.

[0119] Here, the method for manufacturing the coil structure according to Embodiments 1 and 2 of the present invention will be described, including the case that a resin winding mold for winding the coil is required in actual wireless power supply devices. It should be noted that the only difference between the coil structure of Embodiment 1 and the actual coil structure is whether or not a magnetic pole plate 13 is installed at the end of the ferrite base 12, so the manufacturing method of the coil structure is almost the same.

[0120] Figure 13 This is an explanatory diagram showing the method of manufacturing a coil structure for a wireless power supply device according to Embodiment 2 of the present invention.

[0121] First, such as Figure 13 As shown in (a), a resin winding mold 71 for mounting the solenoid coil 33 is installed at the center of the ferrite base 12 (center in the X-axis direction). Next, as... Figure 13 As shown in (b), resin winding molds 81 and 82 for two stepped spiral coils 31 and 32 are installed on both sides of the ferrite base 12. Figure 13 (c) is viewed from the direction of arrow A. Figure 13 (b) Front view, Figure 13 (d) Viewed from the inside (bottom side) Figure 13(b) is the diagram.

[0122] Then, wind the coil. For details on how to wind this coil, refer to [reference needed]. Figure 14 To be discussed later. Finally, as... Figure 13 As shown in (e), magnetic pole plates 13 are installed on the upper part (positive side in the Z-axis direction) or the left and right ends (positive side and negative side in the X-axis direction) of the ferrite base 12. This yields the coil structure for the wireless power supply device according to Embodiment 2 of the present invention.

[0123] Next, let's explain the previous... Figure 13 (e) refers to the winding method of the coil before the step. Figure 14 This is an explanatory diagram showing the winding method of the coil structure for the wireless power supply device according to Embodiment 2 of the present invention.

[0124] First, such as Figure 14 As shown in (a), the spiral coil 32 is wound onto the resin winding mold 82 starting from the outer part of the lower right of the figure, that is, the part indicated by arrow [1] in the figure, and is wound from the outside to the inside into a roughly square shape or a roughly circular shape. Then, the winding end of the spiral coil 32 with steps on the right becomes the innermost part of the lower part of the steps on the right, so from here, as indicated by arrow [2], it passes over the inclined coil winding and through the inside of the resin winding mold 82 at the upper part of the steps (the part indicated by dashed arrow [3]), and the part of the solenoid coil 33 begins to be wound.

[0125] The portion of the solenoid coil 33 begins winding from arrow [4], progressing from right to left in circles around the resin winding mold 71 for the solenoid coil mounted on the ferrite base 12, finally ending at the portion indicated by arrow [5]. From this point onwards... Figure 14 (b) As shown by the dashed arrow [6], it obliquely passes through the inside of the resin winding mold 81 to the lower left (see below). Figure 14 (d)), and the spiral coil 31 is wound onto the resin winding mold 81 starting from the lower left (see arrow [7] in the figure). The spiral coil 31 and the spiral coil 32 are wound in opposite directions.

[0126] Then, similarly to the spiral coil 32, it is wound from the outside to the inside into a roughly square or roughly circular shape. The end of the winding of the stepped spiral coil 31 on the left side becomes the innermost part of the lower part of the step on the left side, so from this point onwards... Figure 14 (c) As indicated by arrow [8], the coil winding is directly led out to the outside and the process ends. Figure 14(d) is a view of the resin winding molds 81 and 82 from the inside (bottom side) after the coil winding has been wound in this manner.

[0127] As in Figure 14 As described above, after the coil winding is completed, the magnetic pole plate 13 is finally installed to obtain the coil structure for the wireless power supply device of Embodiment 2 of the present invention.

[0128] Figure 15 This is an explanatory diagram showing the mounting method of the magnetic pole plate for the coil structure of the wireless power supply device according to Embodiment 2 of the present invention. Figure 15 In this example, we will also take the case where the magnetic pole plate 13 is installed on the upper part (positive side in the Z-axis direction) of the ferrite base 12 as an example.

[0129] Figure 15 (a) indicates the state before the magnetic pole plate 13 is installed on the ferrite base 12. Figure 15 (b) indicates that it is installed with Figure 12 (b) shows the state of the magnetic pole plate 13 up to approximately the same position (length in the X-axis direction). Figure 15 (c) indicates that... Figure 12 (a) shows the same configuration with the longest magnetic pole plate 13 along the X-axis. The magnetic pole plate 13 can be installed using double-sided tape or the like.

[0130] Here, the resonant frequency of the wireless power supply device was compared by gradually changing the length of the magnetic pole plate 13 along the X-axis. The result showed that extending the magnetic pole plate 13 by 1 cm reduced the resonant frequency by approximately 1 kHz. Therefore, by adjusting the length of the magnetic pole plate 13 after winding the coil, individual component differences can be absorbed. Thus, if the magnetic pole plate 13 is installed after the coil winding is completed, it can be used at its highest performance.

[0131] Figure 16 This is an explanatory diagram showing the positional relationship between the magnetic flux passing through the ferrite core and the coil in the coil structure of each of Embodiments 1 and 2 of the present invention for wireless power supply devices. Figure 16 (a) and (b) correspond to implementation method 1. Figure 16 (c) and (d) correspond to implementation method 2. Furthermore, Figure 16 (a) is with Figure 5 (c-2) A diagram with the exact same structure, except for the addition of dashed arrows representing the magnetic flux passing through the ferrite core 11. It should be noted that the magnetic flux is as follows: Figure 5 (a-2) Figure 8 It flows as shown, but in that... Figure 16 The diagram only shows the magnetic flux passing through the interior of the ferrite core 11.

[0132] Figure 16 (a) and Figure 16 (b) This is used to illustrate the situation where the helical coils 31 and 32, in the portion farther from the solenoid coil 33 (near the end of the length of the ferrite core 11 in the X-axis direction), are positioned lower (on the negative side in the Z-axis direction) than the magnetic flux passing through the interior of the ferrite core 11, differing only slightly in their vertical position. That is, in Figure 16 In (a), the coils at both ends are completely positioned at the lower part of the ferrite core 11 (the negative side in the Z-axis direction), but in Figure 16 In (b), it is not completely disposed in the lower part of the ferrite core 11, but rather... Figure 16 (a) A slightly higher configuration, even if such a configuration is configured to be located lower (negative side in the Z-axis direction) than the magnetic flux passing through the interior of the ferrite core 11, is included in the coil structure of the present invention.

[0133] Similarly, Figure 16 (c) and Figure 16 In (d), the helical coils 31 and 32, in the portion farther from the solenoid coil 33 (near the end of the length of the ferrite base 12 in the X-axis direction), are positioned lower (on the negative side in the Z-axis direction) than the magnetic flux passing through the interior of the ferrite base 12 (i.e., the ferrite core 11), differing only slightly in their vertical position. That is, in Figure 16 In (c), the coils at both ends are completely positioned at the lower part of the ferrite core 11 (the negative side in the Z-axis direction), but in Figure 16 In (d), it is not completely disposed in the lower part of the ferrite core 11, but rather... Figure 16 (c) Slightly higher up. However, this is also the case where it is positioned lower than the magnetic flux passing through the interior of the ferrite core 11 (negative side in the Z-axis direction).

[0134] Thus, the coil structure used in the wireless power supply device of Embodiment 2 is the same as that of Embodiment 1. The two helical coils 31 and 32 are located to the left and right of the solenoid coil 33 (positive and negative sides in the X-axis direction with the solenoid coil 33 as the center). In the part close to the solenoid coil 33 (near the center of the length of the ferrite core 11 in the X-axis direction), it is arranged higher than the magnetic flux passing through the interior of the ferrite core 11 (positive side in the Z-axis direction). In the part far from the solenoid coil 33 (near the end of the length of the ferrite core 11 in the X-axis direction), it is arranged lower than the magnetic flux passing through the interior of the ferrite core 11 (negative side in the Z-axis direction). That is, in the state of having steps along the vertical (Z-axis direction) near the center and end in the X-axis direction, it is wound multiple times from the outside to the inside in a roughly square shape or a roughly circular shape to form a step.

[0135] As described above, the coil structure for the wireless power supply device according to Embodiment 2 of the present invention, similar to Embodiment 1, has a structure in which each spiral coil 31, 32 has a step and a solenoid coil 33 is wound between these two spiral coils 31, 32. Therefore, a longer transmission distance between the power supply side coil and the power receiving side coil can be ensured, further improving power transmission efficiency and resulting in a higher performance wireless power supply device. Moreover, because the spiral coils 31, 32 have steps, the performance of the wireless power supply device will not be reduced due to the coil leads. In addition, water cooling pipes for cooling the coil windings can be configured.

[0136] Furthermore, according to Embodiment 2, after the coil winding is wound, the length of the two magnetic pole plates 13 installed on the ferrite base 12 in the left-right direction (X-axis direction) can be adjusted. Therefore, it also has the further advantage of being able to install the magnetic pole plates 13 of the optimal length to adjust the resonant frequency in response to changes in the characteristics of the ferrite core composed of the ferrite base 12 and the two magnetic pole plates 13.

[0137] It should be noted that, within the scope of this invention, the various embodiments can be freely combined, or any constituent elements of the various embodiments can be modified, or any constituent elements of the various embodiments can be omitted.

[0138] Industrial availability The coil structure for the wireless power supply device of the present invention is applicable to the coil structure of wireless power supply devices in various fields such as electronic devices and electric vehicles that require wireless power supply.

[0139] Symbol Explanation 1, 10, 11 Ferrite core (magnetic material) 12 Ferrite base (magnetic base) 13 Magnetic pole plates 21 Helical Coil 22, 27, 33 Solenoid coils 23, 24, 25, and 26 form a planar helical coil with a double helix. 31 and 32 form a stepped spiral coil that constitutes a double helix. Leads of coil windings 41, 42, 51, and 52 Water-cooled pipes 61, 61-1, 61-2, 61-3 71. Winding wire for solenoid coil 33 81, 82 Stepped spiral coils; winding molds for 31, 32

Claims

1. A coil structure for a wireless power supply device, characterized in that, The coil structure includes: The magnetic core is roughly rectangular in shape, with the left and right lengths of the longest side in the X-axis direction, the depth of the second longest side in the Y-axis direction, and the thickness of the shortest side in the Z-axis direction. Two helical coils and one solenoid coil, The solenoid coil is a solenoid coil wound multiple times around the magnetic core, only near the center of its length in the X-axis direction. The two helical coils are located to the left and right of the solenoid coil (on the positive and negative sides of the X-axis with the solenoid coil as the center). Near the center of the magnetic core in the X-axis direction, the coils are positioned higher than the magnetic flux passing through the interior of the magnetic core (positive side of the Z-axis). Near the end of the magnetic core in the X-axis direction, the coils are positioned lower than the magnetic flux passing through the interior of the magnetic core (negative side of the Z-axis). In other words, the coils are wound in a generally square or generally circular shape multiple times from the outside to the inside, forming a stepped structure, with a step-like shape along the vertical (Z-axis) near the center and end of the magnetic core in the X-axis direction.

2. The coil structure for the wireless power supply device according to claim 1, characterized in that, The magnetic core consists of a magnetic base with approximately the same shape as the magnetic core and two magnetic pole plates that can be mounted on the magnetic base. The two magnetic pole plates correspond to the two spiral coils respectively, and can be installed on the upper part (positive side in the Z-axis direction) or the left and right ends (positive side and negative side in the X-axis direction) of the magnetic body base after the two spiral coils are wound.

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