Power transmission device and power supply system

Abstract

To provide a power transmission device and a power feeding system capable of suppressing temperature rise of a metallic foreign object.SOLUTION: In the power feed system, a power transmission device 35 includes a power transmission coil 351 with a gap 3512 formed between adjacent windings, a casing 350 in which the power transmission coil is provided on a top wall 3502 facing a power receiving device 23 and an exhaust port 3505 is formed on a top wall facing a gap in the power transmission coil, and a fan 353 provided inside the casing. The power transmission device has a magnetic body 355 provided in the power transmission coil, which is open at a portion facing the gap and the exhaust port.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a power transmitting device and a power supply system. [Background technology]

[0002] Conventionally, power supply systems that transmit and receive power in a contactless manner have been known. In such power supply systems, if a metallic foreign object is present between the power transmission coil of a power transmission device and the power receiving coil of a power receiving device, the metallic foreign object generates heat. If the metallic foreign object is equal to or larger than a predetermined size, the metallic foreign object can be detected by a change in the value of the current flowing through the power transmission circuit, etc. However, if the metallic foreign object is smaller than the predetermined size, the change in the current value due to the metallic foreign object is small, making it difficult to detect the metallic foreign object.

[0003] For example, a technology is known in which a heat-sensing unit is provided in a power transmission device to detect the heat generated by a metallic foreign object by detecting the temperature. However, this technology may not be able to accurately detect the temperature unless the heat generated by the metallic foreign object is transmitted to the heat-sensing unit.

[0004] For example, when a metallic foreign object made of metal foil or metal plate is placed on the winding of a power transmission coil, the large metallic foreign object will raise the temperature of the winding through thermal conduction, which will be detected by the heat-sensitive part of the temperature sensor, allowing the foreign object to be detected.

[0005] On the other hand, small metallic foreign objects have a small contact area with the winding or the heat-sensing part, which can inhibit heat transfer. In this case, even if the temperature of the metallic foreign object itself rises, the heat-sensing part cannot detect the temperature rise, and there is a risk that power will be transmitted from the power transmitting device while the temperature remains elevated. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-182258 Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a power transmitting device and a power supply system that can suppress a temperature rise of a metallic foreign object. [Means for solving the problem]

[0008] The power transmission device of the embodiment includes a power transmission coil, a casing, and a fan. The power transmission coil has a gap between adjacent windings. The casing has an upper wall facing a power receiving device, and an exhaust port formed in the upper wall facing the gap in the power transmission coil. The fan is provided within the casing. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a configuration of a power supply system according to an embodiment. [Figure 2] FIG. 1 is a perspective view showing a configuration of a cart used in a power supply system according to an embodiment. [Figure 3] FIG. 2 is a block diagram showing the configuration of a control system of the power supply system according to the embodiment. [Figure 4] FIG. 2 is a top view showing the configuration of a power transmission device of the power supply system according to the embodiment. [Figure 5] 1 is a cross-sectional view schematically illustrating the configuration of a power receiving device and a power transmitting device of a power supply system according to an embodiment. [Figure 6] FIG. 2 is a plan view schematically showing the configuration of a first example of a power transmission coil and a magnetic body of a power transmission device according to an embodiment. [Figure 7] FIG. 2 is a plan view schematically showing the configuration of a first example of a power transmitting coil of a power transmitting device according to an embodiment. [Figure 8] FIG. 2 is a plan view schematically showing the configuration of a first example of a magnetic body of a power transmitting device according to an embodiment. [Figure 9] FIG. 10 is a plan view schematically showing a configuration of a second example of a power transmitting coil and a magnetic body of a power transmitting device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] A power supply system according to a first embodiment will be described below with reference to Figs. 1 to 9. Fig. 1 is a perspective view showing the configuration of the power supply system according to the first embodiment, and Fig. 2 is a perspective view of a cart of the power supply system. Fig. 3 is a block diagram showing the configuration of a control system of the power supply system. Fig. 4 is a top view showing the configuration of a power transmission device 35 of the power supply system 1, and Fig. 5 is a cross-sectional view schematically showing the configurations of the power receiving device 23 and the power transmission device 35 of the power supply system 1. Figs. 6 to 9 are plan views schematically showing examples of a power transmission coil 351 and a magnetic body 355.

[0011] 1 and 3, the power supply system 1 includes a power receiving device 23 and a power transmitting device 35. The power receiving device 23 is provided, for example, on a cart 2. A plurality of power transmitting devices 35 are provided, for example, on a cart base 3 that accommodates a plurality of carts 2, along the traveling direction of the carts 2. In the following description of the embodiment, an example will be described in which the power receiving device 23 and the power transmitting device 35 are applied to the cart 2 and the cart base 3 in the power supply system 1.

[0012] 1, the power supply system 1 includes a cart 2 equipped with a power receiving device 23, and a cart base 3 on which a plurality of carts 2 are installed and which is equipped with a power transmitting device 35. In the power supply system 1, the cart base 3 having a plurality of power transmitting devices 35 arranged in one direction stores a plurality of carts 2 each equipped with a power receiving device 23 arranged in one direction, and the plurality of power transmitting devices 35 and the plurality of power receiving devices 23 are arranged opposite each other at a predetermined interval.

[0013] 1 and 2 is a mobile object, such as a shopping cart. The cart 2 includes a frame 11, a basket 12, casters 151 and 152, an electronic device 21, a battery box 223 with a battery 22 provided therein, and a power receiving device 23.

[0014] The frame 11 is configured by assembling a plurality of frame members extending in a plurality of different directions. The frame 11 supports the car section 12, a plurality of casters 151, 152, various electronic devices 21, and a power receiving device 23 at predetermined locations.

[0015] The frame 11 includes, for example, a pair of left and right vertical frame portions 111, a lower frame portion 112, a horizontal frame portion 113, a handle portion 114, and an attachment frame 115. The vertical frame portions 111, the lower frame portion 112, and the horizontal frame portions 113 extend in directions that intersect with each other.

[0016] The vertical frame portion 111 includes a pair of main frames 1111 extending upward from the rear casters 152, a pair of sub-frames 1112 provided on the rear side of the main frames 1111, and a pair of sub-frames 1113 provided on the front side of the main frames 1111. The vertical frame portion 111 extends in the vertical direction behind the car portion 12, and the rear casters 152 are disposed at the lower end thereof.

[0017] The lower frame portion 112 includes a plurality of frame members arranged along the floor surface. The lower frame portion 112 includes, for example, a pair of main frames 1121, a support frame 1123, a front connecting portion 1124, and an attachment portion 1125 provided below the support frame 1123. The main frame 1121 extends forward from the rear caster 152 toward the front caster 151.

[0018] The support frame 1123 is a frame member that extends downward from the horizontal frame portion 113, bends forward at a predetermined height, extends forward, and has a front end that bends upward. The support frame 1123 is configured, for example, as a U-shaped frame member that curves and folds back at the front. The support frame 1123 extends along a plane parallel to the floor inside the main frame 1121. The support frame 1123 forms a basket storage area on its upper side.

[0019] The front connecting portion 1124 extends in the width direction at the front end of the lower end of the cart 2 and connects the front ends of the pair of main frames 1121 together.

[0020] The upper end of the mounting portion 1125 is fixed to a predetermined position on the support frame 1123. The mounting portion 1125 extends downward from the support frame 1123, bends backward at a predetermined height, and continues to extend backward. The mounting portion 1125 is a frame member to which the power receiving device 23 is attached. The mounting portion 1125 extends along a plane parallel to the floor inside the main frame 1121, and forms a support surface that supports the power receiving device 23 on the lower side of the support frame 1123. For example, the mounting portion 1125 is sized so that when the cart 2 is installed on the cart base 3, the power transmitting device 35 provided on the cart base 3 and the power receiving device 23 provided on the mounting portion 1125 are arranged opposite each other with a predetermined distance between them.

[0021] The horizontal frame portion 113 includes a plurality of link frames 1131, 1132, and 1133 that are stretched between the left and right vertical frame portions 111 and extend in the width direction.

[0022] The handle portion 114 is disposed above the rear end portion of the cart 2. The handle portion 114 is disposed contiguous with the upper end portion of the vertical frame portion 111. For example, the handle portion 114 extends in the width direction.

[0023] The mounting frame 115 is connected to the vertical frame portions 111. The mounting frame 115 extends above one of the vertical frame portions 111, for example, and supports various electronic devices 21.

[0024] In the frame 11, the car section 12 is supported on the vertical frame section 111, and a front caster 151 and a rear caster 152 are provided at the front end and rear end of a lower frame section 112 disposed below the car section 12. In addition, in the frame 11, a power receiving device 23 is provided on a mounting section 1125, which is a frame member disposed along the floor surface of the lower frame section 112. In addition, a battery box 223 is provided on the vertical frame section 111. For example, the battery box 223 is supported on a pair of sub-frames 1112 of the vertical frame section 111.

[0025] In addition, the pair of main frames 1121 in the lower frame portion 112 extend obliquely toward the center at the front so that the widthwise spacing at the front is narrow. Therefore, the frame 11 is formed so that the width at the front is narrow and the width at the rear is wide in the forward direction of the cart 2.

[0026] The car section 12 is configured in the shape of a box that opens upward, for example, using a perforated panel member or a mesh-like wire member. The car section 12 is disposed in front of the vertical frame section 111 at a height spaced above the floor. The car section 12 is supported by the vertical frame section 111 on both the left and right sides of its rear end.

[0027] The front caster 151 and the rear caster 152 each include a wheel 153 that rotates in the direction of travel, and a bracket portion 154 that rotatably supports the wheel 153. The bracket portion 154 is rotatably attached to the frame 11. The cart 2 moves when the wheels 153 of the caster 15 rotate on the floor surface. In addition, the traveling direction of the cart 2 can be changed when the bracket portion 154 of the caster 15 rotates.

[0028] Similar to the shapes of the frame 11 and the basket section 12, the front front casters 151 are arranged so that the width from side to side is narrower than the rear rear casters 152. Therefore, when storing multiple carts 2 lined up one behind the other, the carts 2 can be stored so that the frame 11 of the rear cart 2 overlaps along the frame 11 of the front cart 2.

[0029] The electronic device 21 is an information terminal such as a tablet terminal for providing information to a user, or a product reader for acquiring information on a product selected by a user. The electronic device 21 is connected to, for example, a battery 22, and is driven by power from the battery 22. The electronic device 21 may also be a charging device for charging a mobile terminal (for example, a mobile phone, a smartphone, a digital camera, etc.) carried by a user using power from the battery 22.

[0030] In this embodiment, an example is shown in which the electronic device 21 includes a tablet terminal 211 and a product reader 212. The tablet terminal 211 is a computer having a display unit with a touch panel. The tablet terminal 211 is installed with its display unit facing the user positioned on the handle unit 114 side. The tablet terminal 211 displays, for example, information about a product read by the product reader 212. The tablet terminal 211 may also perform a payment process for the product read by the product reader 212.

[0031] The product reader 212 is a device that reads product information. The product reader 212 may also have a display unit that displays the read product information. The product reader 212 is, for example, an RFID tag reader that reads RFID tags or the like attached to products that are put into or taken out of the basket unit 12. The product reader 212 may also be a scanner that reads product identification information, such as a barcode attached to a product.

[0032] The electronic device 21 may be an interface device for connecting a mobile terminal (smartphone, tablet terminal, etc.) owned by a user instead of the tablet terminal 211. The mobile terminal connected to the interface device serving as the electronic device 21 may perform the same processing as the tablet terminal 211 described above. The interface device serving as the electronic device 21 may also charge a battery provided in the mobile terminal. The interface device serving as the electronic device 21 may have a built-in battery 22, or may be connected to a separately provided battery 22.

[0033] The battery box 223 is provided on the frame 11. The battery box 223 is fixed to and supported by, for example, a pair of sub-frames 1112 arranged below the opening / closing panel 121 of the car section 12. The battery 22 is a power supply device that supplies power to the electronic devices 21 mounted on the cart 2, and includes a charging circuit 221 and a battery pack 222. The battery 22 is connected to and charged by the power receiving device 23.

[0034] The charging circuit 221 supplies the power supplied from the load circuit 2325 of the power receiving device 23 to the assembled battery 222 as charging power (charging power). For example, the charging circuit 221 converts the power supplied from the load circuit 2325 into a direct current (charging power) used to charge the assembled battery 222. That is, the charging circuit 221 converts the power from the load circuit 2325 into charging power of a predetermined current value and voltage value for charging the assembled battery 222, and supplies the charging power to the assembled battery 222. The charging circuit 221 charges the assembled battery 222 with the power from the power receiving device 23.

[0035] The battery pack 222 is charged by charging power supplied from the charging circuit 221. The battery pack 222 is also connected to the electronic device 21 and supplies power to the electronic device 21.

[0036] The power receiving device 23 receives power transmitted in a contactless manner and supplies the received power to the electronic device 21 or the battery 22. The power receiving device 23 may be configured to include an output terminal that supplies power to the electronic device 21. In this case, the battery 22 may be configured to be charged by power supplied via the electronic device 21.

[0037] 2, the power receiving device 23 is provided at the bottom of the cart 2. For example, the power receiving device 23 is disposed below the lower frame portion 112. When the cart 2 is stored in the cart base 3, the power receiving device 23 faces one of the multiple power transmitting devices 35 provided on the cart base 3.

[0038] As shown in FIGS. 3 and 5, the power receiving device 23 includes, for example, a casing 230, a power receiving coil 231, a power receiving board 232, and a magnetic body 233.

[0039] The casing 230 accommodates therein the power receiving coil 231 and the power receiving board 232. The casing 230 is connected, for example, to the lower part of the lower frame part 112. As a specific example, the casing 230 is fixed to the attachment part 1125 of the lower frame part 112.

[0040] The underside of the casing 230 is placed on the cart 2 in a position that is aligned with the floor surface on which the cart 2 travels. When multiple carts 2 are stacked and lined up and stored in the cart base 3, the casing 230 is shaped so that it does not overlap with the casings 230 of the power receiving devices 23 of adjacent carts 2 in the front and rear in the traveling direction of the carts 2. Furthermore, when multiple carts 2 are stacked and lined up and stored in the cart base 3, the casing 230 is placed in a position that does not overlap with or interfere with the power receiving devices 23 of adjacent carts 2 in the front and rear in the traveling direction of the carts 2.

[0041] The power receiving coil 231 is disposed within the casing 230. The power receiving coil 231 is, for example, a planar coil formed by winding a litz wire. Alternatively, the power receiving coil 231 is, for example, a planar coil in which a winding that is a coil pattern is formed on a printed circuit board. The power receiving coil 231 has, for example, a planar power receiving surface that receives power. The power receiving surface of the power receiving coil 231 is disposed facing the floor surface on which the cart 2 travels.

[0042] When the power receiving device 23 faces the power transmitting device 35, the power receiving coil 231 is electromagnetically coupled to the power transmitting coil 351. The power receiving coil 231 generates an induced current due to the magnetic field output from the power transmitting coil 351 of the power transmitting device 35.

[0043] The power receiving coil 231 is connected in series with a capacitor 2321 (described later) of the power receiving board 232. The power receiving coil 231, when connected to the capacitor 2321, constitutes a power receiving resonance circuit (resonance element) 239.

[0044] Here, the power receiving resonant circuit 239 configured by the power receiving coil 231 and the capacitor 2321 functions as, for example, an AC power supply that supplies AC power to the rectifier circuit 2322 connected to the power receiving resonant circuit 239. For example, when using a magnetic field resonance method for power transmission, it is desirable to configure the resonant frequency of the power receiving resonant circuit 239 configured by the power receiving coil 231 and the capacitor 2321 to be the same or nearly the same as the resonant frequency of a power transmitting resonant circuit 359 configured by a power transmitting coil 351 and a capacitor 3521 (described later) of the power transmitting device 35. This improves the power transmission efficiency when the power receiving resonant circuit and the power transmitting resonant circuit are electromagnetically coupled.

[0045] When electromagnetic induction is used for power transmission, the power receiving resonant circuit 239 may be configured by the power receiving coil 231 without including the capacitor 2321 .

[0046] The power receiving board 232 includes a capacitor 2321, a rectifier circuit 2322, a voltage conversion circuit 2323, a switching circuit 2324, a load circuit 2325, a control circuit 2326, and a communication circuit 2327. The power receiving board 232 is configured with various processing circuits including the capacitor 2321, the rectifier circuit 2322, the voltage conversion circuit 2323, the switching circuit 2324, the load circuit 2325, the control circuit 2326, the communication circuit 2327, etc., by mounting electronic components and wiring patterns thereon, for example.

[0047] The capacitor 2321 is a capacitor for resonance. The rectifier circuit 2322 rectifies the AC power supplied from the power receiving resonant circuit and converts it into DC power. The rectifier circuit 2322 includes, for example, a rectifier bridge configured with a plurality of diodes. A pair of input terminals of the rectifier bridge are connected to the power receiving resonant circuit 239. The rectifier circuit 2322 full-wave rectifies the AC power supplied from the power receiving resonant circuit 239, and outputs DC power from a pair of output terminals. The rectifier circuit 2322 supplies the DC power to the voltage conversion circuit 2323.

[0048] The voltage conversion circuit 2323 converts the DC voltage output from the rectifier circuit 2322 into a desired DC voltage. For example, two voltage conversion circuits 2323 are provided. One voltage conversion circuit 23231 is connected to, for example, the rectifier circuit 2322 and the switching circuit 2324 (load circuit 2325). One voltage conversion circuit 23231 converts the DC power supplied from the rectifier circuit 2322 into DC power of a voltage suitable for charging, which is output to the load circuit 2325. The other voltage conversion circuit 23232 is connected to the rectifier circuit 2322 and the control circuit 2326. The other voltage conversion circuit 23232 converts the DC power supplied from the rectifier circuit 2322 into DC power suitable for a voltage that operates the control circuit 2326.

[0049] The switching circuit 2324 switches between connection and disconnection of the voltage conversion circuit 23231 and the load circuit 2325. The switching circuit 2324 switches between connection and disconnection of the voltage conversion circuit 23231 and the load circuit 2325 based on a signal from the control circuit 2326, for example.

[0050] The load circuit 2325 is a load that receives DC power of the voltage generated by the voltage conversion circuit 23231. The load circuit 2325 is connected to, for example, a charging circuit 221 that charges the assembled battery 222 with power. The load circuit 2325, together with the charging circuit 221, performs, for example, a charging process of storing DC power of the voltage generated by the voltage conversion circuit 23231 in the assembled battery 222. Note that the load circuit 2325 may not be provided in the power receiving device 23, and the charging circuit 221 of the battery 22 may fulfill the function of the load circuit 2325. Furthermore, if the power receiving device 23 is configured to have an output terminal that supplies power to the electronic device 21, the power receiving device 23 may not have the load circuit 2325. That is, in this embodiment, a configuration is described in which the power receiving device 23 has a load circuit 2325, but the load circuit 2325 may be provided outside the power receiving device 23, and the switching circuit 2324 of the power receiving device 23 may be connected to the external load circuit via a connector or the like.

[0051] The control circuit 2326 controls the operation of the load circuit 2325. The control circuit 2326 is a processing circuit. The control circuit 2326 includes, for example, a processor and a memory. The processor executes arithmetic processing. The processor performs various processes based on, for example, programs stored in the memory and data used in the programs. The memory stores the programs, data used in the programs, and the like. The control circuit 2326 may be configured with a microcomputer and / or an oscillator circuit, etc.

[0052] The communication circuit 2327 communicates information relating to power transmission and reception with the power transmitting device 35 in a contactless manner.

[0053] The magnetic body 233 is provided, for example, on the opposite side to the power receiving surface of the power receiving coil 231. The magnetic body 233 is formed in a sheet or plate shape.

[0054] 1 and 2, the cart 2 is stored in a cart base 3 provided at a predetermined storage position. In FIGS. 1 and 2, the cart base 3 stores a plurality of carts 2 in a nested manner.

[0055] The cart base 3 as a storage device for storing the cart 2 includes a guide base 31 as a base portion, a cart gate 32, and a plurality of power transmission devices 35 supported by the guide base 31.

[0056] The guide base 31 includes a plate-shaped support base 311 that is laid at a predetermined storage position. The support base 311 has, on its upper surface, a plurality of guide rails 312 that extend in one direction and a plurality of guide grooves 313 formed between the plurality of guide rails 312. The support base 311 also has protrusions and grooves that guide the storage positions of the plurality of carts 2. The guide base 31 regulates the movement of the front and rear wheels 153 using the guide rails 312 and the guide grooves 313, thereby guiding the traveling direction of the cart 2 on the support base 311. The guide base 31 also supports a plurality of power transmission devices 35 at equal intervals.

[0057] The cart gate 32 includes a pair of poles 322 standing upright from both sides of the guide base 31, and side bars 323 arranged at a predetermined height on both side edges of the guide base 31 and extending in one direction.

[0058] A plurality of power transmission devices 35 are provided between a pair of guide grooves 313 of the guide base 31, along which a pair of front wheels 153 of the cart 2 are guided. The plurality of power transmission devices 35 are arranged side by side in the extending direction of the pair of guide grooves 313 of the guide base 31. Here, the extending direction of the guide grooves 313 is the traveling direction of the cart 2 on the guide base 31. In other words, the extending direction of the guide grooves 313 is the stacking direction of the plurality of carts 2 on the guide base 31. The plurality of power transmission devices 35 face the power receiving devices 23 of the plurality of carts 2 stored in a stack on the cart base 31. The power transmission devices 35 transmit power to the power receiving devices 23 of the opposing carts 2 in a non-contact manner.

[0059] As shown in FIGS. 3 to 5, the power transmitting device 35 includes, for example, a casing 350, a power transmitting coil 351, a power transmitting board 352, a fan 353, an AC adapter 354, and a magnetic body 355.

[0060] The casing 350 is formed, for example, in the shape of a rectangular box. The casing 350 houses a power transmitting coil 351, a power transmitting board 352, and a fan 353 inside. The casing 350 faces the power receiving device 23 of the cart 2 housed in the cart base 3, with a predetermined gap between them. The gap between the casing 350 and the casing 230 of the power receiving device 23 is several mm, specifically, 1 mm to 10 mm.

[0061] The casing 350 has, for example, a rectangular bottom wall 3501, a rectangular top wall 3502 facing the bottom wall 3501, and four side walls 3503 connecting the bottom wall 3501 and the top wall 3502.

[0062] For example, a power transmitting board 352 is disposed on the bottom wall 3501. For example, a power transmitting coil 351 is fixed to the top wall 3502. When the power transmitting device 35 is provided on the cart base 3, the top surface of the top wall 3502 extends, for example, along the traveling direction of the cart 2. For example, the top surface of the top wall 3502 extends horizontally. A plurality of exhaust ports 3505 are formed in the top wall 3502.

[0063] The exhaust port 3505 is configured by, for example, one or more openings formed in the upper wall 3502. The exhaust port 3505 is formed in various shapes, such as a circle, a rectangle, or an arc. The multiple exhaust ports 3505 face multiple gaps 3512 formed in the winding 3511 (described later) and multiple magnetic holes 3551 formed in the magnetic body 355 (described later). The multiple exhaust ports 3505 are formed in positions and shapes that allow air discharged from the multiple exhaust ports 3505 and coming into contact with the casing 230 of the power receiving device 23 facing the power transmitting device 35 to move into the area of ​​the upper wall 3502 where the power transmitting coil 351 is provided. The multiple exhaust ports 3505 are formed, for example, at positions symmetrical with respect to the center of the power transmitting coil 351 or a predetermined position close to the center. Note that the arrangement of the multiple exhaust ports 3505 is not limited to being symmetrical.

[0064] That is, the multiple exhaust ports 3505 are appropriately set so long as they are arranged so that air exhausted from the exhaust ports 3505 is supplied to a position on the upper surface of the upper wall 3502 opposite the area where the power transmission coil 351 is provided.

[0065] At least one of the four side walls 3503 has an air intake 3507 formed therein for introducing outside air into the casing 350 .

[0066] A predetermined gap is formed between bottom wall 3501 and top wall 3502 of casing 350. Here, the predetermined gap between bottom wall 3501 and top wall 3502 refers to the distance between opposing bottom wall 3501 and top wall 3502 that allows airflow from air intake port 3507 formed in side wall 3503 to air exhaust port 3505. As a specific example, bottom wall 3501 and top wall 3502 are spaced apart by a width that allows a gap to be formed that generates airflow between power transmitting board 352 arranged on bottom wall 3501 and power transmitting coil 351 arranged on top wall 3502. For example, the width of the gap between power transmitting board 352 arranged on bottom wall 3501 and power transmitting coil 351 arranged on top wall 3502 is several centimeters, specifically, 1 cm to 10 cm.

[0067] The power transmitting coil 351 is, for example, a planar coil including a winding 3511. The power transmitting coil 351 is formed, for example, by winding a litz wire. The power transmitting coil 351 has, for example, a planar power transmitting surface that transmits power. For example, the winding 3511 is fixed to a magnetic body 355. The power transmitting coil 351 is formed by winding the winding 3511 a plurality of times around a flat frame that is open in the center. For example, the power transmitting coil 351 may be formed in various shapes, such as a square shape with two intersecting sides of approximately the same length or a rectangular shape such as a rectangle that is long in one direction, a circle, or an ellipse.

[0068] The power transmitting surface of the power transmitting coil 351 is arranged along the floor surface on which the cart 2 travels. The power transmitting surface of the power transmitting coil 351 is housed in the cart base 3 and is aligned with the power receiving surface of the power receiving coil 231 provided on the opposing cart 2. Each power transmitting coil 351 of the multiple power transmitting devices 35 is provided at a position facing the power receiving coil 231 of each power receiving device 23 of the multiple carts 2 housed in the cart base 3.

[0069] As a specific example, in the power transmitting coil 351, for example, among the winding 3511 wound multiple times, a plurality of gaps 3512 are formed between adjacent windings in the plane direction of the power transmitting surface. The gaps 3512 are formed in two or more locations in the winding direction of the winding 3511. Note that, although the examples in FIGS. 6 to 9 show examples in which the gaps 3512 are formed in two locations in the winding direction of the winding 3511, the gaps 3512 may be formed in three locations, or may be formed in four or more locations.

[0070] The plurality of gaps 3512 are formed outside the region toward the center of the power transmitting coil 351, which is surrounded by the innermost portion of the wound winding 3511. That is, the gaps 3512 are formed by bending a portion of the winding 3511 that is on the inner side of the outermost winding 35111, among the adjacent windings 3511 wound multiple times. The bent shape of the winding 3511 may be a curved shape with a predetermined curvature radius, or may be a polygonal shape such as a V-shape or a rectangle formed by combining straight lines at a predetermined angle.

[0071] For example, an example of a method for manufacturing winding 3511 in which gap 3512 is formed by bending a portion thereof may involve manufacturing winding 3511 so that a portion thereof is bent, or manufacturing a winding without a bend and then bending a portion of the winding. Alternatively, another example of a method for manufacturing winding 3511 in which gap 3512 is formed by bending a portion thereof may involve separately constructing an outer winding without a bend and an inner winding with a bend, and then connecting the outer winding and the inner winding.

[0072] Alternatively, the multiple gaps 3512 are formed by separating a winding 3511 that is more inward than the outermost winding 35111 from an adjacent winding 3511 on the outside of this winding 3511 by a gap equal to or greater than the gap 3512 toward the center of the power transmitting coil 351. Note that the distance between adjacent windings 3511 that form the gap 3512 is wider than the distance between adjacent windings 3511 that do not form the gap 3512.

[0073] As a specific example, in the power transmission coil 351, for example, of the multiple wound windings 3511, multiple gaps 3512 are formed between the outer winding 35113 including the outermost winding 35111 and the inner winding 35114 including the innermost winding 35112.

[0074] The gap 3512 may be formed by bending and separating a portion of the adjacent winding 3511 of the winding 3511 wound multiple times and located inside the outermost winding 35111.

[0075] Here, an example of an outer winding 35113 and an inner winding 35114 of a winding 3511 wound three times will be described. In this case, the outer winding 35113 is the outermost winding 35111, or the outermost winding 35111 and the winding 3511 adjacent to this outermost winding 35111. Also, the inner winding 35114 is the innermost winding 35112 and the winding 3511 adjacent to this innermost winding 35112, or the innermost winding 35112.

[0076] Next, an example of the outer winding 35113 and inner winding 35114 of the winding 3511 wound four times will be described. In this case, the outer winding 35113 is either the outermost winding 35111 only, or the winding 3511 up to the second or third outermost turn, including the outermost winding 35111. The inner winding 35114 is either the innermost winding 3511 up to the third innermost turn, including the innermost winding 35112, or the innermost winding 35112 only.

[0077] An example of the outer winding 35113 and inner winding 35114 of the winding 3511 having five turns will now be described. In this case, the outer winding 35113 is either only the outermost winding 35111, or the second, third, or fourth turn from the outside including the outermost winding 35111. The inner winding 35114 is either the fourth, third, or fourth turn from the inside including the innermost winding 35112, or only the innermost winding 35112.

[0078] 6 shows an example of a power transmitting coil 351 according to the first embodiment, in which the inner winding 35114 is bent toward the center of the winding 3511 of the power transmitting coil 351, thereby forming two gaps 3512. The power transmitting coil 351 according to the first embodiment is, for example, an example of a winding 3511 formed by five turns in the shape of a rectangular frame that is long in one direction, and the winding 3511 from the innermost winding 35112 to the third turn on the long side is defined as the inner winding 35114. In the power transmitting coil 351 according to the first embodiment, the inner winding 35114 is bent, thereby forming two gaps 3512 between the outer winding 35113 and the inner winding 35114.

[0079] 9 shows an example of a power transmitting coil 351 according to the second embodiment, in which the inner winding 35114 is spaced a predetermined distance from the outer winding 35113 at the center of the power transmitting coil 351, thereby forming two gaps 3512. The power transmitting coil 351 according to the second embodiment is, for example, an example of a winding 3511 formed with four turns in the shape of a rectangular frame that is long in one direction, and the winding 3511 from the innermost winding 35112 to the second turn on the short side is defined as the inner winding 35114. In the power transmitting coil 351 according to the second embodiment, the inner winding 35114 is spaced a predetermined distance from the outer winding 35113, thereby forming two gaps 3512 between the outer winding 35113 and the inner winding 35114.

[0080] The power transmitting coil 351 is disposed on the upper wall 3502 so that the center of the power transmitting coil 351 is at the center of the upper wall 3502 of the casing 350 or on the central side of the upper wall 3502. The plurality of gaps 3512 of the power transmitting coil 351 face the plurality of exhaust ports 3505 formed in the upper wall 3502, respectively.

[0081] When the power receiving device 23 and the power transmitting device 35 face each other, the power transmitting coil 351 is electromagnetically coupled to the power receiving coil 231 .

[0082] The power transmitting coil 351 is connected in series to a capacitor 3521 (described later) of the power transmitting board 352. The power transmitting coil 351 is connected to the capacitor 3521 to form a power transmitting resonant circuit (resonant element) 359.

[0083] Here, it is desirable that the resonant frequency of the power transmitting resonant circuit 359 constituted by the power transmitting coil 351 and the capacitor 3521 is configured to be the same as or almost the same as the oscillation frequency of the oscillation circuit of the control circuit 3528. When an electromagnetic induction method is used for power transmission, the power transmitting resonant circuit 359 may be constituted by the power transmitting coil 351 without including the capacitor 3521.

[0084] The power transmission board 352 includes a capacitor 3521, a power transmission circuit 3522, a voltage conversion circuit 3523, a switching circuit 3524, a current sensor 3526, a current detection circuit 3527, a control circuit 3528, and a communication circuit 3529. For example, electronic components and wiring patterns are mounted on the power transmission board 352, thereby configuring various processing circuits including the capacitor 3521, the power transmission circuit 3522, the voltage conversion circuit 3523, the switching circuit 3524, the current sensor 3526, the current detection circuit 3527, the control circuit 3528, the communication circuit 3529, etc.

[0085] The capacitor 3521 and the power transmitting coil 351 form a resonant circuit.

[0086] The power transmitting circuit 3522 generates transmission power and supplies the generated transmission power to the power transmitting coil 351. For example, the power transmitting circuit 3522 generates AC power as transmission power by switching DC power supplied via an AC adapter 354 or the like under the control of the control circuit 3528. The power transmitting coil 351 outputs power that can be received by the power receiving device 23 according to the transmission power supplied from the power transmitting circuit 3522. The power transmitting circuit 3522 generates AC power at a frequency that is the same as or approximately the same as the resonant frequency of the power transmitting resonant circuit 359. The power transmitting circuit 3522 has a switching element such as an FET. The power transmitting circuit 3522 is switched on and off by the output of an oscillator circuit in the control circuit 3528. The power output from the power transmitting circuit 3522 is transmitted to the power receiving device 23 by utilizing electromagnetic coupling, such as electromagnetic induction or magnetic field resonance, between the power transmitting coil 351 and the power receiving coil 231.

[0087] The voltage conversion circuit 3523 converts the voltage of a DC power supply supplied via, for example, an AC adapter 354 connected to a commercial power supply into a desired DC voltage. As a specific example, the voltage conversion circuit 3523 generates power for operating the control circuit 3528 and supplies it to the control circuit 3528.

[0088] The switching circuit 3524 switches between connection and disconnection of the AC adapter 354 and the power transmitting circuit 3522. The switching circuit 3524 switches the state of power supply from the power transmitting device to the power receiving device by connecting or disconnecting the AC adapter 354 and the power transmitting circuit 3522 based on a control signal from the control circuit 3528. For example, the switching circuit 3524 supplies to the power transmitting circuit 3522 either DC power of a voltage supplied from an external DC power supply or DC power of a voltage obtained by lowering the DC power supplied from the external DC power supply by the voltage conversion circuit 3523. The switching circuit 3524 switches the DC power to be supplied to the power transmitting circuit 3522 based on the control of the control circuit 3528.

[0089] The current sensor 3526 detects a direct current input to the power transmitting circuit 3522. The current sensor 3526 is a minute resistor connected between the switching circuit 3524 and the power transmitting circuit 3522. A potential (current detection signal) corresponding to the current transmitted from the switching circuit 3524 to the power transmitting circuit 3522 is generated in the current sensor 3526.

[0090] The current detection circuit 3527 amplifies the minute signal detected by the current sensor 3526 and outputs it to the control circuit 3528 .

[0091] The control circuit 3528 controls the operation of the power transmitting circuit 3522. The control circuit 3528 is a processing circuit. The control circuit 3528 includes, for example, a processor and a memory. The processor executes arithmetic processing. The processor performs various processes based on, for example, programs stored in the memory and data used in the programs. The memory stores the programs, data used in the programs, and the like. The control circuit 3528 may be configured with a microcomputer and / or an oscillator circuit, etc.

[0092] For example, the control circuit 3528 controls the frequency of AC power output from the power transmitting circuit 3522 and controls the on / off operation of the power transmitting circuit 3522. For example, the control circuit 3528 controls the switching circuit 3524 to switch between a state in which a magnetic field is generated in the power transmitting coil 351 (power transmitting state) and a state in which a magnetic field is not generated in the power transmitting coil 351 (standby state). The control circuit 3528 may also perform control to change the timing of power transmission by causing the power transmitting coil 351 to intermittently generate a magnetic field.

[0093] When the power receiving device 23 faces the power transmitting device 35, the control circuit 3528 first performs an authentication process to confirm whether the power receiving device 23 is a legitimate power receiving device 23. After the authentication is established, the control circuit 3528 transmits power from the power transmitting device 35 to the power receiving device 23 and starts a charging operation.

[0094] Furthermore, for example, the memory of the control circuit 3528 stores, as a threshold value, the value of the current that flows when a metallic foreign object 99 made of a metallic material and having a predetermined size is present between the power transmitting coil 351 and the power receiving coil 231.

[0095] Note that here, the metallic foreign object 99 refers to an object that is at least partially or entirely made of a metallic material. The metallic foreign object 99 is located between the power receiving device 23 and the power transmitting device 35 and on the power transmitting coil 351, and generates heat when the power transmitting coil 351 transmits power. For example, examples of the metallic foreign object 99 include various objects such as a coin, a metal piece, a piece of paper or resin film provided with a metal film or metal foil such as aluminum, a clip, a hairpin, etc.

[0096] Furthermore, a metallic foreign object 99 of a size that allows a current value stored as a threshold value to flow is, for example, a metallic foreign object 99 whose maximum dimension is greater than 3 cm.

[0097] Then, the control circuit 3528 compares the current value detected by the current sensor 3526 and the current detection circuit 3527 with a threshold value. If the current value detected by the current sensor 3526 and the current detection circuit 3527 is different from the normal current value, such as when the current value exceeds the threshold value, the control circuit 3528 controls the switching circuit 3524 to put the power transmitting coil 351 into a standby state in which it does not generate a magnetic field.

[0098] Furthermore, the control circuit 3528 controls, for example, driving and stopping of the fan 353. As a specific example, the control circuit 3528 drives the fan 353 when the power transmitting coil 351 is in a power transmitting state. Furthermore, the control circuit 3528 stops the fan 353 when the power transmitting coil 351 is in a standby state.

[0099] The communication circuit 3529 communicates information related to power transmission and reception with the communication circuit 2327 of the power receiving device 23 in a contactless manner.

[0100] Fan 353 is disposed within casing 350, takes in air through intake port 3507, and exhausts air through exhaust port 3505. Fan 353 is provided, for example, on the inner surface of side wall 3503, adjacent to intake port 3507. Fan 353 is connected, for example, to control circuit 3528, and its driving and stopping are controlled by control circuit 3528.

[0101] The AC adapter 354 is, for example, disposed outside the casing 350 and connected to the power transmission board 352 .

[0102] The magnetic body 355 is provided, for example, on the side opposite the power transmission surface of the power transmission coil 351. The magnetic body 355 is formed in a sheet or plate shape. Note that the magnetic body 355 has a magnetic body hole 3551 that opens at a portion facing the exhaust port 3505 and the gap 3512 so that at least the gap 3512 of the power transmission coil 351 connects the exhaust port 3505 in the upper wall 3502 and the internal space of the casing 350. Alternatively, a configuration may be adopted in which a plurality of magnetic bodies 355 are provided at intervals so as not to be located at a portion facing the exhaust port 3505 and the gap 3512, and the intervals (gaps) between the plurality of magnetic bodies 355 serve as the magnetic body hole 3551. In this way, the magnetic body hole 3551 faces the exhaust port 3505 and the gap 3512, thereby connecting the internal space of the casing 350 and the exhaust port 3505 in the upper wall 3502.

[0103] According to the power feeding system 1 having the power transmitting device 35 configured in this manner, a plurality of gaps 3512 are formed in the winding 3511 of the power transmitting coil 351, and a magnetic material hole 3551 is formed in the magnetic material 355, the magnetic material hole 3551 being open at a portion facing the plurality of gaps 3512 in the power transmitting coil 351. The winding 3511 and the magnetic material hole 3551 are arranged to face the exhaust port 3505 in the top wall 3502 of the casing 350. This allows the interior of the casing 350 to be connected to the exhaust port 3505 via the gaps 3512 in the winding 3511 and the magnetic material hole 3551 in the magnetic material 355. Therefore, when the fan 353 is driven, the airflow of air blown out from the exhaust port 3505 is blocked by the casing 230 of the power receiving device 23 above the top wall 3502 and flows in the plane direction of the upper surface of the top wall 3502.

[0104] Therefore, even if a metallic foreign object 99 made of a metallic material generates heat on the upper surface of the upper wall 3502 of the casing 350 of the power transmitting device 35, the heat is discharged from the exhaust port 3505, and the metallic foreign object 99 is cooled by the airflow caused by the casing 230 of the power receiving device 23 to flow in the surface direction of the upper wall 3502. Even if the metallic foreign object 99 made of a metallic material generates heat, the power transmitting device 35 can suppress a temperature rise of the metallic foreign object 99 by cooling the metallic foreign object 99. Furthermore, the airflow flowing in the surface direction of the upper wall 3502 can also move small or light metallic foreign objects 99.

[0105] Therefore, even if the metallic foreign object 99 is present on the upper surface of the region where the horizontally extending power transmission coil 351 of the power transmission device 35 is disposed, the power transmission device 35 and the power supply system 1 can suppress a temperature rise of the metallic foreign object 99. The power transmission device 35 and the power supply system 1 prevent wireless power transmission while the temperature of the metallic foreign object 99 remains elevated.

[0106] Furthermore, when the control circuit 3528 detects a metallic foreign object 99 of a predetermined size due to a change in the current flowing through the power transmitting coil 351, it stops power transmission, thereby suppressing heat generation by the metallic foreign object 99. Furthermore, when the power transmitting coil 351 is in a power transmitting state, the control circuit 3528 drives the fan 353, thereby generating an airflow on the upper surface of the power transmitting device 35 only when there is a risk that the metallic foreign object 99 will be heated by the power transmitting coil 351. Therefore, the power transmitting device 35 can reduce power consumption and suppress noise generated by driving the fan 353.

[0107] According to the power transmitting device 35 and the power supply system 1 of the above-described embodiment, heat generation by the metal foreign object 99 can be suppressed.

[0108] Note that the embodiment is not limited to the above-described example. In the above-described example, the power transmitting coil 351 has the winding 3511 in which the plurality of gaps 3512 are formed, and the winding 3511 is provided on the magnetic body 355. However, the present invention is not limited to this. For example, the winding 3511 may be a coil pattern formed on a printed circuit board. In the case of using such a winding 3511, the coil pattern (winding 3511) on the printed circuit board may be provided with the plurality of gaps 3512, and openings facing the magnetic body holes 3551 of the magnetic body 355 may be formed in the portions of the printed circuit board where the gaps 3512 are formed.

[0109] Furthermore, in the above example, the cart base 3 has been described as having a configuration including a plurality of guide grooves 313 that guide the movement of the wheels 153 of the cart 2, but the configuration is not limited to this. The cart base 3 may be configured to guide the cart 2 so that the power receiving coil 231 of the power receiving device 23 mounted on the cart 2 is located at a predetermined storage position facing the power transmitting coil 351 of the power transmitting device 35. For example, the cart base 3 may not be configured such that each guide groove 313 guides the movement of all the wheels 153 of the cart 2, but may be configured such that some of the guide grooves 313 guide the movement of the wheels 153 on one side.

[0110] In the above example, the power receiving device 23 of the power supply system 1 that supplies power contactlessly is described as a shopping cart as an example of the cart 2. However, the cart 2 equipped with the power receiving device 23 is not limited to a shopping cart, and may be, for example, a picking cart used in a warehouse. Furthermore, the application of the power supply system 1 is not limited to the cart 2, but may be applied to supplying power contactlessly to various other terminals. Furthermore, for example, the shape and specific configuration of the cart 2 and the cart base 3 are not limited to those in the above embodiment.

[0111] According to the power transmitting device and the power supply system of at least one of the embodiments described above, it is possible to suppress heat generation from a metallic foreign object at least part of which is made of a metallic material.

[0112] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0113] 1...power supply system, 2...cart, 3...cart base, 11...frame, 12...basket section, 15...caster, 21...electronic device, 22...battery, 23...power receiving device, 31...guide base, 32...cart gate, 35...power transmitting device, 99...metal foreign matter, 111...vertical frame section, 112...lower frame section, 113...horizontal frame section, 114...handle section, 115...mounting frame, 121...opening / closing panel, 151...front wheel caster, 152...rear wheel caster, 153...wheel, 154...bracket section, 211...tablet terminal, 212...product reader, 221...charging circuit, 222...battery pack, 223...battery box, 230...casing, 231...receiving coil, 232...receiving board, 233...magnetic material, 239...receiving resonance circuit, 311...support base, 312...guide rail, 313...guide groove, 322...pole, 323...side bar, 350...casing, 351...transmitting coil, 352...transmitting board, 353...fan, 354...AC adapter, 355...magnetic material, 359...transmitting resonance circuit , 1111...main frame, 1112...subframe, 1113...subframe, 1121...main frame, 1123...support frame, 1124...front connecting portion, 1125...mounting portion, 1131...link frame, 1132...link frame, 1133...link frame, 2321...capacitor, 2322...rectifier circuit, 2323...voltage conversion circuit, 2324...switching circuit, 2325...load circuit, 2326...control circuit, 2327...communication circuit, 3501...bottom wall, 3502...upper wall , 3503...side wall, 3505...exhaust port, 3507...intake port, 3511...winding, 3512...gap, 3521...capacitor, 3522...power transmission circuit, 3523...voltage conversion circuit, 3524...switching circuit, 3526...current sensor, 3527...current detection circuit, 3528...control circuit, 3529...communication circuit, 3551...magnetic hole, 23231...voltage conversion circuit, 23232...voltage conversion circuit, 35111...outermost winding, 35112...innermost winding, 35113...outer winding, 35114...inner winding.

Claims

1. a power transmission coil having a gap formed between adjacent windings; a casing having an upper wall on which the power transmitting coil is provided facing a power receiving device, and an exhaust port formed in the upper wall facing the gap of the power transmitting coil; a fan provided within the casing; A power transmission device comprising:

2. The power transmitting device according to claim 1 , further comprising: a magnetic body provided on the power transmitting coil, the magnetic body having openings at portions facing the gap and the exhaust port.

3. The power transmitting device according to claim 1 or 2, wherein the gap is formed by bending a part of the adjacent winding that is located more inward than an outermost winding.

4. 4. The power transmission device according to claim 1, wherein the gap is formed by separating a winding that is more inward than an outermost winding among the adjacent windings from the winding adjacent to the outermost winding.

5. a power transmission device according to any one of claims 1 to 4, the power transmission device being arranged in a cart base that accommodates a plurality of carts along a traveling direction of the carts; a power receiving device provided at a bottom of the cart and configured to transmit and receive power to and from the power transmitting device; A power supply system comprising:

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