JP7722935B2 - Contactless power supply device - Google Patents

Description

The present invention relates to a contactless power supply device.

Patent Document 1 discloses a technology for a contactless power transfer device in which the power transmission coil and power receiving coil are spiral coils, the power receiving coil is attached directly or indirectly to a metal member, a non-conductive magnetic thin film is formed on the surface of the metal member in a certain area centered on the attachment position of the power receiving coil, and the shape of the non-conductive magnetic thin film is the same as the shape of the power transmission coil extended in the vehicle width direction.

Japanese Patent Application Laid-Open No. 2017-076653

If a thin magnetic film is placed on the back of the coil so that it covers the coil, the magnetic flux density will be high and the effect of the magnetic material will be reduced.

The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a contactless power supply device that can prevent the effectiveness of magnetic materials from being reduced.

To solve the above-mentioned problems and achieve the object, the contactless power supply device of the present invention is a contactless power supply device that supplies power contactlessly from a power transmission coil to a power receiving coil, wherein the power receiving coil is formed by winding a wire around a winding axis, and is characterized by comprising: a first magnetic body that is arranged on the opposite side of the power receiving coil from the power transmission coil so as to intersect with the winding axis; and a second magnetic body that is arranged in a non-contact manner with the power receiving coil and the first magnetic body, and is arranged with respect to the power receiving coil outside a position half the coil width between the inner and outer circumferences of the power receiving coil in a direction perpendicular to the winding axis.

This improves the transmission efficiency between the coils compared to when the second magnetic body is not present, while reducing the magnetic flux density of the second magnetic body, thereby preventing the effectiveness of the magnetic body from being reduced.

Furthermore, in the above, the second magnetic body may be arranged on the opposite side of the first magnetic body from the receiving coil side.

This prevents the effect of the magnetic body from being reduced in a configuration in which the second magnetic body is placed on the opposite side of the first magnetic body from the receiving coil side.

Furthermore, in the above, the second magnetic body may be arranged on the opposite side of the power receiving coil from the first magnetic body.

This prevents the effect of the magnetic body from being reduced in a configuration in which the second magnetic body is placed on the opposite side of the receiving coil from the first magnetic body.

Furthermore, in the above, an intermediate magnetic body may be provided that extends in the same direction as the winding axis, with one end in contact or not in contact with the first magnetic body and the other end in not in contact with the second magnetic body.

This allows the maximum magnetic flux density of the second magnetic body to be reduced more than if there were no intermediate magnetic body.

Furthermore, in the above, an extension portion may be provided that extends from the other end of the relay magnetic body along the second magnetic body in a direction perpendicular to the winding axis.

This improves the transmission efficiency between the coils and reduces the maximum magnetic flux density of the second magnetic body compared to when the extension is not present.

The non-contact power supply device according to the present invention has the advantage of being able to prevent the effectiveness of the magnetic material from being reduced.

FIG. 1 is a diagram showing a schematic configuration of a contactless power supply device according to a first embodiment. FIG. 2 is a diagram showing a contactless power receiving device and a contactless power transmitting device. 3A and 3B are diagrams showing the power receiving coil as viewed from below and above, respectively. 4A shows a case where the second magnetic body is arranged with an overlap rate of 100% relative to the receiving coil, FIG. 4B shows a case where the second magnetic body is arranged with an overlap rate of 50% relative to the receiving coil, and FIG. 4C shows a case where the second magnetic body is arranged with an overlap rate of 0% relative to the receiving coil. FIG. 5 is a graph showing the relationship between the overlap ratio of the second magnetic body with respect to the power receiving coil and the transmission efficiency between the coils. FIG. 6 is a graph showing the relationship between the overlap ratio of the second magnetic body with respect to the power receiving coil and the maximum magnetic flux density of the second magnetic body. FIG. 7 is a diagram illustrating a contactless power receiving device and a contactless power transmitting device according to the second embodiment. FIG. 8 is a diagram for explaining the positional relationship between the end of the power receiving coil and the end of the second magnetic body. FIG. 9 is a graph showing the relationship between the end position of the second magnetic body and the magnetic flux density. FIG. 10 is a graph showing the relationship between the end position of the second magnetic body and the transmission efficiency. FIG. 11 is a diagram showing a case where a relay magnetic body is provided between the first magnetic body and the second magnetic body. FIG. 12 is a graph showing the relationship between the presence or absence of relay magnetic bodies and the transmission efficiency between coils. FIG. 13 is a graph showing the relationship between the presence or absence of relay magnetic bodies and the maximum magnetic flux density of the second magnetic bodies. FIG. 14 is a diagram for explaining the positional relationship between the end of the power receiving coil, the end of the second magnetic body, and the end of the relay magnetic body. FIG. 15 is a graph showing the relationship between the end position of the second magnetic body and the transmission efficiency between the coils. FIG. 16 is a graph showing the relationship between the end position of the second magnetic body and the maximum magnetic flux density of the second magnetic body. FIG. 17 is a diagram showing a case where the relay magnetic body is extended along the second magnetic body. 18(a) shows a case where the extension amount of the extension portion along the second magnetic body in the radial direction is 0 [mm], FIG. 18(b) shows a case where the extension amount of the extension portion along the second magnetic body in the radial direction is 20 [mm], and FIG. 18(c) shows a case where the extension amount of the extension portion along the second magnetic body in the radial direction is 40 [mm]. FIG. 19 is a graph showing the relationship between the extension amount along the second magnetic body of the extension portion in the radial direction and the transmission efficiency between the coils. FIG. 20 is a graph showing the relationship between the extension amount of the extension portion along the second magnetic body in the radial direction and the maximum magnetic flux density of the second magnetic body. Fig. 21(a) is a diagram showing a case where the overlap amount of the extension portion with respect to the second magnetic body is 0 [mm]. Fig. 21(b) is a diagram showing a case where the overlap amount of the extension portion with respect to the second magnetic body is 20 [mm]. Fig. 21(c) is a diagram showing a case where the overlap amount of the extension portion with respect to the second magnetic body is 40 [mm]. Fig. 21(d) is a diagram showing a case where the overlap amount of the extension portion with respect to the second magnetic body is 60 [mm]. Fig. 21(e) is a diagram showing a case where the overlap amount of the extension portion with respect to the second magnetic body is 80 [mm]. FIG. 22 is a graph showing the relationship between the overlap amount of the extension portion with respect to the second magnetic body and the maximum magnetic flux density of the second magnetic body. FIG. 23 is a graph showing the relationship between the overlap amount of the extension portion with respect to the second magnetic body and the transmission efficiency between the coils. Fig. 24(a) is a diagram showing a case where second magnetic bodies are provided corresponding to two opposing sides of a first magnetic body. Fig. 24(b) is a diagram showing a case where second magnetic bodies are provided corresponding to four sides of the first magnetic body. Fig. 24(c) is a diagram showing a case where second magnetic bodies longer than the sides of the first magnetic body are provided corresponding to two opposing sides of the first magnetic body. Fig. 24(d) is a diagram showing a case where second magnetic bodies are provided to surround the periphery of the first magnetic body. Fig. 25(a) shows the case where the second magnetic body of the mouth shape is provided at 50[%] elongation, Fig. 25(b) shows the case where the second magnetic body of the mouth shape is provided at 100[%] elongation, and Fig. 25(c) shows the case where the second magnetic body of the mouth shape is provided at 200[%] elongation. 26(a) shows a case where the second magnetic body of the dex-shaped structure is provided at 50[%] elongation, FIG. 26(b) shows a case where the second magnetic body of the dex-shaped structure is provided at 100[%] elongation, and FIG. 26(c) shows a case where the second magnetic body of the dex-shaped structure is provided at 200[%] elongation. 27(a) shows the case where the I-shaped second magnetic body is provided at 50[%] elongation, FIG. 27(b) shows the case where the I-shaped second magnetic body is provided at 100[%] elongation, and FIG. 27(c) shows the case where the I-shaped second magnetic body is provided at 200[%] elongation. Fig. 28(a) shows the case where the second magnetic body of the mold is provided at 50[%] elongation, Fig. 28(b) shows the case where the second magnetic body of the mold is provided at 100[%] elongation, and Fig. 28(c) shows the case where the second magnetic body of the mold is provided at 200[%] elongation. FIG. 29 is a diagram showing some of the conditions for misalignment of the power receiving coil unit with respect to the power transmitting coil. FIG. 30 is a graph showing the relationship between the elongation rate of the second magnetic body and the average transmission efficiency. FIG. 31 is a graph showing the relationship between the area of the second magnetic body and the average transmission efficiency.

(Embodiment 1)
A first embodiment of a contactless power supply device according to the present invention will be described below. However, the present invention is not limited to this embodiment.

1 is a diagram showing the schematic configuration of a contactless power transfer device 10 according to the first embodiment. The contactless power transfer device 10 according to the first embodiment is configured with a contactless power receiving device 4 having a power receiving coil 41, which is a vehicle-side coil, provided on a vehicle 1 equipped with a motor generator 2 and a battery 3, and a plurality of contactless power transmitting devices 5 having power transmitting coils 51, which are ground-side coils, installed along the vehicle's traveling direction on a road 6, which is a road on which the vehicle 1 can travel. Note that well-known configurations can be used as the basic configurations of the contactless power receiving device 4 and the contactless power transmitting device 5. The contactless power receiving device 4 can contactlessly receive power transmitted (supplied) from a power transmitting coil 52 of the contactless power transmitting device 5 having a power transmitting coil 51, via the power receiving coil 41. The power received by the contactless power receiving device 4 from the contactless power transmitting device 5 is then supplied to the motor generator 2 and the battery 3.

Fig. 2 is a diagram showing the contactless power receiving device 4 and the contactless power transmitting device 5. Fig. 3(a) is a diagram showing a bottom view of the power receiving coil 41. Fig. 3(b) is a diagram showing a top view of the power receiving coil 41.

As shown in Figures 2, 3(a), and 3(b), the contactless power receiving device 4 includes a wound power receiving coil 41, a first magnetic body 42, and a second magnetic body 43. In this embodiment, at least the power receiving coil 41, the first magnetic body 42, and the second magnetic body 43 form a power receiving coil unit.

In this embodiment, the power receiving coil 41 is a flat spiral coil formed by winding a wire in a square shape on the same plane around the winding axis AX, and has an air core surrounded by the wire. The "radial direction" in FIG. 2 refers to the radial direction of the power receiving coil 41, which is a spiral coil formed by winding a wire. The "axial direction" in FIG. 2 refers to the direction in which the winding axis of the power receiving coil 41 extends. In the following description, unless otherwise specified, the "radial direction" refers to the radial direction of the power receiving coil 41, and the "axial direction" refers to the direction in which the winding axis of the power receiving coil 41 extends.

The first magnetic body 42 is a square, plate-shaped base core made of a ferromagnetic material such as ferrite. The first magnetic body 42 is arranged on the upper surface of the receiving coil 41 in the axial direction (on the opposite side of the receiving coil 41 from the transmitting coil 51) so as to intersect with the winding axis AX, and is positioned at least on the projection plane of the receiving coil 41 (covering at least the receiving coil 41). The receiving coil 41 and the first magnetic body 42 are arranged so as not to come into direct contact with each other via an air gap or resin.

The second magnetic body 43 is an additional core composed of multiple plate-shaped members made of a ferromagnetic material such as ferrite. The second magnetic body 43 is positioned on the axially opposite side of the first magnetic body 42 from the power receiving coil 41 (the upper surface side of the first magnetic body 42) so as not to come into direct contact with the power receiving coil 41 and the first magnetic body 42 via a gap or resin. Furthermore, the second magnetic body 43 is positioned radially outward from a position that is half the width (thickness) of one side of the square-shaped power receiving coil 41 (w/2), where w is the radial width (thickness) of one side of the power receiving coil 41. In other words, the second magnetic body 43 is positioned without contact with the power receiving coil 41 and the first magnetic body 42, and is positioned relative to the power receiving coil 41 outside a position that is half the coil width between the inner and outer circumferences of the power receiving coil 41 in a direction perpendicular to the winding axis AX. Furthermore, the area radially inward from the position where w/2 is half the width of one side of the power receiving coil 41, including the air-core portion, is a prohibited area where the second magnetic body 43 must not be placed.

As shown in FIG. 2, the contactless power transmission device 5 includes a wound power transmission coil 51. In this embodiment, the power transmission coil 51 is a flat spiral coil formed by winding a wire in a square shape on the same plane, and has an air core surrounded by the wire. Furthermore, the planar size of the power transmission coil 51 is larger than the planar size of the power receiving coil 41.

Figure 4(a) shows a case where the second magnetic body 43 is arranged with an overlap ratio of 100% with respect to the receiving coil 41. Figure 4(b) shows a case where the second magnetic body 43 is arranged with an overlap ratio of 50% with respect to the receiving coil 41. Figure 4(c) shows a case where the second magnetic body 43 is arranged with an overlap ratio of 0% with respect to the receiving coil 41. The overlap ratio of the second magnetic body 43 with respect to the receiving coil 41 represents the proportion of one side of the receiving coil 41 that is covered by the second magnetic body 43 in the radial direction. For example, an overtap ratio of 100% represents a state in which the second magnetic body 43 covers the entire side of the receiving coil 41 in the radial direction, as shown in Figure 4(a). An overlap ratio of 50% represents a state in which the second magnetic body 43 covers from the outside to half the width of one side of the receiving coil 41 in the radial direction, as shown in Figure 4(b). Furthermore, an overlap rate of 0% indicates a state in which the second magnetic body 43 does not cover one side of the power receiving coil 41 in the radial direction, and the end face of the power receiving coil 41 and the end face of the second magnetic body 43 are positioned at the same radial position, as shown in Figure 4(b).

Figure 5 is a graph showing the relationship between the overlap ratio of the second magnetic body 43 with respect to the receiving coil 41 and the transmission efficiency between the coils. Figure 6 is a graph showing the relationship between the overlap ratio of the second magnetic body 43 with respect to the receiving coil 41 and the maximum magnetic flux density of the second magnetic body 43. Note that the analysis conditions were a thickness of 5 mm for the first magnetic body 42 and a thickness of 1 mm for the second magnetic body 43.

As shown in Figure 5, the relationship between the overlap ratio of the second magnetic body 43 relative to the receiving coil 41 and the transmission efficiency between the coils (between the transmitting coil 51 and the receiving coil 41) shows that the presence of the second magnetic body 43 improves the transmission efficiency between the coils compared to when the second magnetic body 43 is not present, regardless of the overlap ratio, and that the transmission efficiency is equivalent regardless of the overlap ratio.

Furthermore, as shown in Figure 6, the relationship between the overlap rate of the second magnetic body 43 relative to the receiving coil 41 and the maximum magnetic flux density of the second magnetic body 43 is such that when the overlap rate is less than 50%, the maximum magnetic flux density of the second magnetic body 43 can be reduced, and when the overlap rate is 0%, the maximum magnetic flux density of the second magnetic body 43 can be reduced by 15%.

Therefore, in the contactless power transfer device 10 according to this embodiment, the second magnetic body 43 is positioned radially outward from the position halfway along the width of one side of the power receiving coil 41; in other words, the overlap rate of the second magnetic body 43 with respect to the power receiving coil 41 is less than 50%. This improves the transmission efficiency between the coils compared to when the second magnetic body 43 is not present, while reducing the magnetic flux density of the second magnetic body 43, thereby preventing the effect of the magnetic body from being reduced.

(Embodiment 2)
Next, a contactless power supply device according to a second embodiment of the present invention will be described. Note that, in the contactless power supply device 10 according to the second embodiment, descriptions of the same parts as those in the first embodiment will be omitted as appropriate.

Figure 7 shows a contactless power receiving device 4 and a contactless power transmitting device 5 according to embodiment 2.

In the contactless power transfer device 10 according to the second embodiment, as shown in FIG. 7 , the first magnetic body 42 is disposed on the upper surface of the power receiving coil 41 in the axial direction, and the second magnetic body 43 is disposed on the lower surface of the power receiving coil 41 in the axial direction (the side of the power receiving coil 41 opposite the first magnetic body 42). The second magnetic body 43 is disposed so as not to come into direct contact with the power receiving coil 41 and the first magnetic body 42 via a gap or resin. In addition, in this embodiment, the second magnetic body 43 is disposed so as not to cover one side of the power receiving coil 41 in the radial direction (apart from the projection plane of the power receiving coil 41), and so that the end face of the power receiving coil 41 and the end face of the second magnetic body 43 are positioned at the same radial position, i.e., the overlap rate is 0%.

Figure 8 is a diagram illustrating the positional relationship between the end of the receiving coil 41 and the end of the second magnetic body 43. Figure 9 is a graph showing the relationship between the end position of the second magnetic body 43 and magnetic flux density. Figure 10 is a graph showing the relationship between the end position of the second magnetic body 43 and transmission efficiency.

In this embodiment, as shown in FIG. 8 , the position of the end face of the power receiving coil 41 is set as the reference 0 mm, the side farther from the end face of the power receiving coil 41 in the radial direction is set as the positive side, and the side closer to the power receiving coil 41 in the radial direction is set as the negative side. In this embodiment, the end position of the second magnetic body 43 is determined based on the distance between the end face of the power receiving coil 41 and the end face of the second magnetic body 43. Here, when the width w of one side of the power receiving coil 41 in the radial direction is 40 mm, the position 20 mm (-20 mm) from the reference 0 mm toward the negative side in the radial direction is the position at half the width of one side of the power receiving coil 41 in the radial direction.

As shown in Figures 9 and 10, when the end position of the second magnetic body 43 is located on the negative side and is located further negative in the radial direction than the position at half the width of one side of the receiving coil 41 (-20 mm), the magnetic flux density of the second magnetic body 43 increases sharply and the transmission efficiency between the coils decreases.

Thus, even in a configuration in which the second magnetic body 43 is disposed on the underside of the power receiving coil 41, as in the case of the contactless power transfer device 10 according to embodiment 2, by positioning the end of the second magnetic body 43 radially outward from the position that is half the width of one side of the power receiving coil 41, it is possible to improve the transmission efficiency between the coils compared to when the second magnetic body 43 is not present, while reducing the magnetic flux density of the second magnetic body 43, thereby preventing the effect of the magnetic body from being reduced.

(Embodiment 3)
Next, a third embodiment of the contactless power supply device 10 according to the present invention will be described. Note that, in the contactless power supply device 10 according to the third embodiment, descriptions of the same parts as those in the first and second embodiments will be omitted as appropriate.

Figure 11 shows an example in which a relay magnetic body 44 is provided between a first magnetic body 42 and a second magnetic body 43.

In the contactless power receiving device 4 of the contactless power supply device 10 according to embodiment 3, as shown in FIG. 11 , a first magnetic body 42 is arranged on the upper surface of the power receiving coil 41 in the axial direction, and a second magnetic body 43 is arranged on the lower surface of the power receiving coil 41 in the axial direction (the opposite side of the power receiving coil 41 from the first magnetic body 42). The second magnetic body 43 is arranged so as not to cover one side of the power receiving coil 41 in the radial direction (apart from the projection plane of the power receiving coil 41), and so that the end face of the power receiving coil 41 and the end face of the second magnetic body 43 are positioned at the same radial position, i.e., the overlap rate is 0%.

In this embodiment, a plate-shaped relay magnetic body 44 is provided that extends in the axial direction (the same direction as the winding axis AX), with one end side surface in contact with the end face of the first magnetic body 42 and the other end surface facing the second magnetic body 43. The relay magnetic body 44 is arranged so as not to come into direct contact with the second magnetic body 43 via a gap or resin. The relay magnetic body 44 may be in contact with the first magnetic body 42 or may be separated from it. In the contactless power transfer device 10 according to embodiment 3, a receiving coil unit is formed by at least the receiving coil 41, the first magnetic body 42, the second magnetic body 43, and the relay magnetic body 44.

Figure 12 is a graph showing the relationship between the presence or absence of relay magnetic material 44 and the transmission efficiency between coils. As shown in Figure 12, it can be seen that the transmission efficiency between coils is improved when relay magnetic material 44 is present compared to when relay magnetic material 44 is not present.

Figure 13 is a graph showing the relationship between the presence or absence of the relay magnetic body 44 and the maximum magnetic flux density of the second magnetic body 43. As shown in Figure 13, the maximum magnetic flux density of the second magnetic body 43 is lower when the relay magnetic body 44 is present than when the relay magnetic body 44 is not present.

Therefore, in the contactless power supply device 10 according to embodiment 3, by providing the relay magnetic body 44 in addition to the first magnetic body 42 and the second magnetic body 43, it is possible to improve the transmission efficiency between the coils compared to when the relay magnetic body 44 is not provided, while reducing the maximum magnetic flux density of the second magnetic body 43, thereby preventing the effect of the magnetic body from being reduced.

Figure 14 is a diagram illustrating the positional relationship between the end of the receiving coil 41, the end of the second magnetic body 43, and the end of the relay magnetic body 44.

In this embodiment, as shown in FIG. 14 , the position of the end face of the receiving coil 41 is defined as the reference 0 mm. The radial side farther from the end face of the receiving coil 41 is defined as the positive side, and the radial side closer to the receiving coil 41 is defined as the negative side. In this embodiment, the end position of the second magnetic body 43 is determined based on the distance between the end face of the second magnetic body 43 and the end face of the receiving coil 41. Here, if the width w of one side of the receiving coil 41 in the radial direction is 40 mm, then a position 20 mm (-20 mm) negative from the reference 0 mm in the radial direction corresponds to half the width of one side of the receiving coil 41 in the radial direction. Furthermore, the end face of the first magnetic body 42 is located 10 mm (+10 mm) positive from the reference 0 mm in the radial direction. Furthermore, the end position of the relay magnetic body 44, which is provided in contact with the end face of this first magnetic body 42, is located 15 mm (+15 mm) radially from the reference 0 mm toward the positive side.

Figure 15 is a graph showing the relationship between the end position of the second magnetic body 43 and the transmission efficiency between the coils. Figure 16 is a graph showing the relationship between the end position of the second magnetic body 43 and the maximum magnetic flux density of the second magnetic body 43.

As shown in Figures 15 and 16, by positioning the end position of the second magnetic body 43 on the positive side (radially outward) of the end position of the relay magnetic body 44, the transmission efficiency between the coils decreases slightly, but it is clear that the maximum magnetic flux density of the second magnetic body 43 can be further reduced.

(Embodiment 4)
Next, a fourth embodiment of the contactless power supply device 10 according to the present invention will be described. Note that, in the contactless power supply device 10 according to the fourth embodiment, descriptions of the same parts as those in the first, second and third embodiments will be omitted as appropriate.

Figure 17 shows the relay magnetic body 44 extended along the second magnetic body 43.

In the contactless power transfer device 10 according to embodiment 4, as shown in FIG. 17 , the second magnetic body 43 is disposed on the power transmission coil 51 side of the power receiving coil 41 in the axial direction. The first magnetic body 42 is disposed on the opposite side of the power receiving coil 41 from the power transmission coil 51 side in the axial direction. The second magnetic body 43 is disposed so as not to overlap the power receiving coil 41; in other words, the second magnetic body 43 is disposed outside the projection plane of the power receiving coil 41.

The contactless power supply device 10 according to the fourth embodiment also includes a relay magnetic body 44 that connects the first magnetic body 42 and the second magnetic body 43 in the axial direction and is located between the first magnetic body 42 and the second magnetic body 43. The relay magnetic body 44 is arranged via a gap or resin to avoid direct contact with the power receiving coil 41. Furthermore, the relay magnetic body 44 is arranged via a gap or resin to avoid direct contact with the second magnetic body 43. For example, an analysis was performed under the same conditions except for whether the relay magnetic body 44 and the second magnetic body 43 were in contact. When the relay magnetic body 44 and the second magnetic body 43 were in direct contact, the magnetic flux density was 300 mT, and when the relay magnetic body 44 and the second magnetic body 43 were not in contact, the magnetic flux density was 199 mT. The first magnetic body 42 and the relay magnetic body 44 may be in contact or may be separated.

Furthermore, as shown in FIG. 17 , the contactless power transfer device 10 according to embodiment 4 has an extension portion 45 that extends radially along the second magnetic body 43 from the end of the relay magnetic body 44 on the second magnetic body 43 side. The relay magnetic body 44 and the extension portion 45 may be formed integrally or separately. Furthermore, in the contactless power transfer device 10 according to embodiment 4, the power receiving coil unit is configured by at least the power receiving coil 41, the first magnetic body 42, the second magnetic body 43, the relay magnetic body 44, and the extension portion 45.

Since magnetic flux density tends to increase around the receiving coil 41, as shown in FIG. 17 , it is possible to reduce the magnetic flux density by extending the extension portion 45 radially from the end of the relay magnetic body 44 on the second magnetic body 43 side along the second magnetic body 43 in a direction away from the receiving coil 41. Therefore, in this embodiment, with the positional relationship between the relay magnetic body 44 and the second magnetic body 43 fixed, an analysis was conducted of the magnetic flux density and transmission efficiency between the coils when the extension portion 45 radially extends along the second magnetic body 43 from the end of the relay magnetic body 44 on the second magnetic body 43 side.

The radial extension of the extension portion 45 along the second magnetic body 43 was set to 0 mm, 20 mm, 40 mm, 60 mm, 80 mm, and 100 mm. For each extension, the axial gap (GAP) between the relay magnetic body 44 (extension portion 45) and the second magnetic body 43 was set to 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm.

Figure 18(a) shows the case where the extension amount of the extension portion 45 along the second magnetic body 43 in the radial direction is 0 mm. Figure 18(b) shows the case where the extension amount of the extension portion 45 along the second magnetic body 43 in the radial direction is 20 mm. Figure 18(c) shows the case where the extension amount of the extension portion 45 along the second magnetic body 43 in the radial direction is 40 mm.

Figure 19 is a graph showing the relationship between the amount of extension of the extension portion 45 along the second magnetic body 43 in the radial direction and the transmission efficiency between the coils. Figure 20 is a graph showing the relationship between the amount of extension of the extension portion 45 along the second magnetic body 43 in the radial direction and the maximum magnetic flux density of the second magnetic body 43.

As shown in Figures 19 and 20, regardless of the size of the gap (GAP) between the relay magnetic body 44 and the second magnetic body 43, the greater the radial extension of the extension portion 45 along the second magnetic body 43, the more the transmission efficiency between the coils improves and the maximum magnetic flux density of the second magnetic body 43 decreases.

In addition, in this embodiment, the point where the end of the relay magnetic body 44 and the end of the second magnetic body 43 are aligned at a position 20 mm radially away from the side of the relay magnetic body 44 is set to 0, and while the position of the second magnetic body 43 is kept fixed, the extension portion 45 is extended radially along the second magnetic body 43, and the transmission efficiency between the coils and the maximum magnetic flux density of the second magnetic body 43 are analyzed according to the amount of overlap of the extension portion 45 with the second magnetic body 43.

Figure 21(a) is a diagram showing the case where the overlap amount of the extension portion 45 with respect to the second magnetic body 43 is 0 mm. Figure 21(b) is a diagram showing the case where the overlap amount of the extension portion 45 with respect to the second magnetic body 43 is 20 mm. Figure 21(c) is a diagram showing the case where the overlap amount of the extension portion 45 with respect to the second magnetic body 43 is 40 mm. Figure 21(d) is a diagram showing the case where the overlap amount of the extension portion 45 with respect to the second magnetic body 43 is 60 mm. Figure 21(e) is a diagram showing the case where the overlap amount of the extension portion 45 with respect to the second magnetic body 43 is 80 mm.

Figure 22 is a graph showing the relationship between the overlap amount of the extension portion 45 with respect to the second magnetic body 43 and the maximum magnetic flux density of the second magnetic body 43. Figure 23 is a graph showing the relationship between the overlap amount of the extension portion 45 with respect to the second magnetic body 43 and the transmission efficiency between the coils.

As shown in Figure 22, regardless of the size of the gap (GAP) between the intermediate magnetic body 44 (extension portion 45) and the second magnetic body 43 in the axial direction, once the extension portion 45 is extended radially along the second magnetic body 43 and overlaps the second magnetic body 43, the maximum magnetic flux density of the second magnetic body 43 increases up to an overlap amount of 20 mm. Then, as the extension portion 45 is further extended radially along the second magnetic body 43 to overlap it, and the overlap amount exceeds 20 mm, the maximum magnetic flux density of the second magnetic body 43 decreases.

Furthermore, as shown in Figure 23, regardless of the size of the gap (GAP) between the relay magnetic body 44 (extension portion 45) and the second magnetic body 43 in the axial direction, the transmission efficiency between the coils increases when the extension portion 45 of the relay magnetic body 44 extends radially along the second magnetic body 43 and overlaps with the second magnetic body 43, compared to an arrangement in which the extension portion 45 does not overlap with the second magnetic body 43 (overlap amount 0 [mm]).

(Embodiment 5)
Next, a fifth embodiment of the contactless power supply device 10 according to the present invention will be described. Note that, in the contactless power supply device 10 according to the fifth embodiment, descriptions of the same parts as those in the first, second, third and fourth embodiments will be omitted as appropriate.

Next, we analyzed the maximum magnetic flux density of the second magnetic body 43 when the second magnetic body 43 was provided in different shapes on the upper surface of the power receiving coil 41 in the axial direction, as shown in Figures 24(a) to 24(d). Figure 24(a) shows a case where the second magnetic body 43 is provided to correspond to two opposing sides of the first magnetic body 42. Figure 24(b) shows a case where the second magnetic body 43 is provided to correspond to four sides of the first magnetic body 42. Figure 24(c) shows a case where the second magnetic body 43, which is longer than the length of the sides of the first magnetic body 42, is provided to correspond to two opposing sides of the first magnetic body 42. Figure 24(d) shows a case where the second magnetic body 43 is provided to surround the first magnetic body 42.

When the second magnetic body 43 was provided relative to the first magnetic body 42 as shown in FIG. 24(a), the maximum magnetic flux density of the second magnetic body 43 was 344 mT. When the second magnetic body 43 was provided relative to the first magnetic body 42 as shown in FIG. 24(b), the maximum magnetic flux density of the second magnetic body 43 was 260 mT. When the second magnetic body 43 was provided relative to the first magnetic body 42 as shown in FIG. 24(c), the maximum magnetic flux density of the second magnetic body 43 was 1754 mT. When the second magnetic body 43 was provided relative to the first magnetic body 42 as shown in FIG. 24(d), the maximum magnetic flux density of the second magnetic body 43 was 269 mT. This shows that the maximum magnetic flux density of the second magnetic body 43 decreases in the order of Figures 24(b), 24(d), 24(a), and 24(c) when the second magnetic body 43 is disposed relative to the first magnetic body 42. Furthermore, it can be said that the manner in which the second magnetic body 43 is disposed relative to the first magnetic body 42 as shown in Figure 24(b) results in the lowest maximum magnetic flux density of the second magnetic body 43.

Next, in this embodiment, the effect of improving transmission efficiency depending on the shape of the second magnetic body 43 was verified by varying the conditions using the shape of the second magnetic body 43 (M-shaped, X-shaped, I-shaped, and C-shaped) and the size of the second magnetic body 43 as parameters.

Figure 25(a) shows the case where the mouth-shaped second magnetic body 43 is provided at 50% elongation. Figure 25(b) shows the case where the mouth-shaped second magnetic body 43 is provided at 100% elongation. Figure 25(c) shows the case where the mouth-shaped second magnetic body 43 is provided at 200% elongation.

Figure 26(a) shows a cross-shaped second magnetic body 43 with a 50% elongation. Figure 26(b) shows a cross-shaped second magnetic body 43 with a 100% elongation. Figure 26(c) shows a cross-shaped second magnetic body 43 with a 200% elongation.

Figure 27(a) shows an example where the I-shaped second magnetic body 43 is provided at 50% elongation. Figure 27(b) shows an example where the I-shaped second magnetic body 43 is provided at 100% elongation. Figure 27(c) shows an example where the I-shaped second magnetic body 43 is provided at 200% elongation.

Figure 28(a) shows the case where the second magnetic body 43 of the mold is provided at 50% elongation. Figure 28(b) shows the case where the second magnetic body 43 of the mold is provided at 100% elongation. Figure 28(c) shows the case where the second magnetic body 43 of the mold is provided at 200% elongation.

In Figures 25 to 28, the dimensions of the receiving coil 41 (the dimensions of the first magnetic body 42) are 400 mm x 400 mm, and the dimensions of the transmitting coil 51 are 700 mm x 700 mm. The condition under which the second magnetic body 43 is extended from the end of the receiving coil 41 to the same dimensions as the transmitting coil 51 is defined as 100% extension, half the length of 100% extension is defined as 50% extension, and twice the length of 100% extension is defined as 200% extension.

Fig. 29 is a diagram showing some of the conditions for misalignment of the power receiving coil unit with respect to the power transmitting coil 51. The power receiving coil unit shown in Fig. 29 is composed of at least the power receiving coil 41, a first magnetic body 42, and a second magnetic body 43. The misalignment of the power receiving coil unit with respect to the power transmitting coil 51 is the amount of misalignment in the X and Y directions of the center point _O4 of the power receiving coil unit (power receiving coil 41) with respect to the center point _O5 of the power transmitting coil 51.

The analysis conditions for the positional misalignment of the receiving coil unit relative to the transmitting coil 51 were set as 0 mm, 175 mm, and 350 mm in the Y direction, and 0 mm, 87.5 mm, 175 mm, 262.5 mm, and 350 mm in the X direction. Each combination of positional misalignment in the X and Y directions was analyzed, and the average value (average transmission efficiency) for all analysis conditions was plotted in a graph.

The analysis results are shown in Figures 30 and 31. Figure 30 is a graph showing the relationship between the elongation rate of the second magnetic body 43 and the average transmission efficiency. In Figure 30, (1) is the second magnetic body 43 with a cross shape, (2) is the second magnetic body 43 with an I shape, (3) is the second magnetic body 43 with a cross shape, and (4) is the second magnetic body with a mouth shape. Figure 30 also shows the transmission efficiency curve when the horizontal axis represents the elongation rate of the second magnetic body 43.

Figure 31 is a graph showing the relationship between the area of the second magnetic body 43 and the average transmission efficiency. In Figure 31, (1) is a square-shaped second magnetic body 43, (2) is an I-shaped second magnetic body 43, (3) is a cross-shaped second magnetic body 43, and (4) is a square-shaped second magnetic body. Figure 31 also shows a transmission efficiency curve when the horizontal axis represents the area of the second magnetic body 43.

As can be seen from Figure 30, the average transmission efficiency for each extension ratio was highest when the second magnetic body 43 was a mouth shape, followed by a cross shape, a square shape, and an I shape. Furthermore, since the extension ratio can be said to be equal to the length of one side of the power receiving coil unit, the mouth shape can be said to be the ideal shape when the length of one side of the power receiving coil unit cannot be adjusted when installing it in the vehicle 1.

Furthermore, as can be seen from Figure 31, when the shape of the second magnetic body 43 is a square, the highest transmission efficiency is achieved under the analysis conditions (extension ratio of up to 225%]), but the area of the second magnetic body 43 also needs to be large. Therefore, if there is room for the size of the power receiving coil unit when installed in the vehicle 1, it can be said that shapes of the second magnetic body 43 that are cross-shaped, I-shaped, and J-shaped, and especially I-shaped and J-shaped, are effective.

REFERENCE SIGNS LIST 1 vehicle 2 motor generator 3 battery 4 non-contact power receiving device 5 non-contact power transmitting device 6 road 10 non-contact power feeding device 41 power receiving coil 42 first magnetic body 43 second magnetic body 44 relay magnetic body 45 extension portion 51 power transmitting coil

Claims (3)

A contactless power supply device that supplies power from a power transmitting coil to a power receiving coil in a contactless manner,
The power receiving coil is formed by winding a wire around a winding axis,
a first magnetic body arranged on an opposite side of the power receiving coil from the power transmitting coil so as to intersect with the winding axis;
a second magnetic body that is disposed in a non-contact state with the power receiving coil and the first magnetic body, and that is disposed with respect to the power receiving coil outside a position that is half the coil width between an inner circumference and an outer circumference of the power receiving coil in a direction perpendicular to the winding axis;
Equipped with
The non-contact power supply device , wherein the second magnetic body is disposed on the opposite side of the first magnetic body from the power receiving coil side . A contactless power supply device that supplies power from a power transmitting coil to a power receiving coil in a contactless manner,
The power receiving coil is formed by winding a wire around a winding axis,
a first magnetic body arranged on an opposite side of the power receiving coil from the power transmitting coil so as to intersect with the winding axis;
a second magnetic body that is disposed in a non-contact state with the power receiving coil and the first magnetic body, and that is disposed with respect to the power receiving coil outside a position that is half the coil width between an inner circumference and an outer circumference of the power receiving coil in a direction perpendicular to the winding axis;
Equipped with
the second magnetic body is disposed on the opposite side of the power receiving coil from the first magnetic body side,
A contactless power supply device characterized by including a relay magnetic body extending in the same direction as the winding axis, one end of which is in contact or non-contact with the first magnetic body, and the other end of which is in non- contact with the second magnetic body. The contactless power supply device according to claim 2 , further comprising an extension portion that extends from the other end of the relay magnetic body along the second magnetic body in a direction perpendicular to the winding axis.