Power transmission equipment 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 feeding system, a power transmission device 35 includes a power transmission coil 351 with a center side opening, 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 an opening 3506 in the power transmission coil, and a fan 353 provided inside the casing. The exhaust port faces the power receiving device when power is transmitted between the power transmission coil and the power receiving device. The casing has a surface facing the power receiving device along the horizontal direction.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] Embodiments of the present invention relate to a power transmission device and a power supply system.

Background Art

[0002] Conventionally, a power supply system that transmits and receives power non - contact is known. In such a power supply system, if there is a metal foreign object at least partially formed of a metal material between the power transmission coil of the power transmission device and the power reception coil of the power reception device, the metal foreign object generates heat. If this metal foreign object is larger than a predetermined size, the metal foreign object can be detected by a change in the current value detected by a power transmission circuit or the like. However, for a metal foreign object smaller than the predetermined size, the current value changed by the metal foreign object is small, and it is difficult to detect the metal foreign object.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a power transmission device and a power supply system capable of suppressing the temperature rise of a metal foreign object.

Means for Solving the Problems

[0005] The power transmission device of the embodiment includes a power transmission coil, a casing, and a fan. The power transmission coil has an opening on the central side. The casing has an upper wall facing the power reception device, and the power transmission coil is provided on the upper wall, and an exhaust port facing the opening of the power transmission coil is formed on the upper wall. The fan is provided inside the casing. An air intake port is formed on the side wall of the casing. The fan is provided on the inner surface of the side wall adjacent to the air intake port. central side The exhaust port is formed by a plurality of openings arranged intermittently in an annular shape. ​ [Brief explanation of the drawing]

[0006] [Figure 1] A perspective view showing the configuration of the power supply system according to the embodiment. [Figure 2] A perspective view showing the configuration of a cart used in a power supply system according to an embodiment. [Figure 3] A block diagram showing the configuration of the control system of the power supply system according to the embodiment. [Figure 4] A top view showing the configuration of the power transmission device of the power supply system according to the embodiment. [Figure 5] A schematic cross-sectional view showing the configuration of the power receiving device and power transmitting device of the power supply system according to this embodiment. [Modes for carrying out the invention]

[0007] The power supply system according to the first embodiment will be described below with reference to Figures 1 to 5. Figure 1 is a perspective view showing the configuration of the power supply system according to the first embodiment, and Figure 2 is a perspective view of the cart of the power supply system. Figure 3 is a block diagram showing the configuration of the control system of the power supply system. Figure 4 is a top view showing the configuration of the power transmission device 35 of the power supply system 1, and Figure 5 is a schematic cross-sectional view showing the configuration of the power receiving device 23 and the power transmission device 35 of the power supply system 1.

[0008] As shown in Figures 1 and 3, the power supply system 1 comprises a power receiving device 23 and a power transmitting device 35. The power receiving device 23 is provided, for example, on a cart 2. The power transmitting devices 35 are provided, for example, in a cart base 3 that accommodates a plurality of carts 2, along the direction of travel of the carts 2. In the following description of embodiments, the power supply system 1 will describe an example in which the power receiving device 23 and the power transmitting device 35 are applied to the carts 2 and the cart base 3.

[0009] As shown in Figure 1, the power supply system 1 comprises a cart 2 equipped with a power receiving device 23, and a cart base 3 on which multiple carts 2 are installed and which is equipped with a power transmitting device 35. In the cart base 3, which is equipped with multiple power transmitting devices 35 arranged in one direction, multiple carts 2, each equipped with a power receiving device 23, are stored in a line in one direction, and the multiple power transmitting devices 35 and the multiple power receiving devices 23 are arranged facing each other at a predetermined interval.

[0010] The cart 2 shown in Figures 1 and 2 is a mobile device, such as a shopping cart. The cart 2 comprises a frame 11, a basket 12, casters 151 and 152, electronic equipment 21, a battery box 223 containing a battery 22, and a power receiving device 23.

[0011] The frame 11 is constructed by assembling multiple frame members that extend in multiple different directions. The frame 11 supports the cage section 12, multiple casters 151, 152, various electronic devices 21, and power receiving device 23 at predetermined locations.

[0012] The frame 11 comprises, for example, a pair of left and right vertical frame sections 111, a lower frame section 112, a horizontal frame section 113, a handle section 114, and a mounting frame 115. The vertical frame sections 111, the lower frame section 112, and the horizontal frame section 113 extend in directions that intersect each other.

[0013] The vertical frame section 111 comprises a pair of main frames 1111 extending upward from the rear wheel casters 152, a pair of subframes 1112 provided on the rear side of the main frames 1111, and a pair of subframes 1113 provided on the front side of the main frames 1111. The vertical frame section 111 extends vertically behind the basket section 12, with the rear wheel casters 152 positioned at its lower end.

[0014] The lower frame section 112 comprises a plurality of frame members arranged along the floor surface. The lower frame section 112 includes, for example, a pair of main frames 1121, a support frame 1123, a front connecting section 1124, and a mounting section 1125 provided below the support frame 1123. The main frame 1121 extends forward from the rear wheel caster 152 toward the front wheel caster 151.

[0015] The support frame 1123 extends downward from the horizontal frame portion 113, bends forward at a predetermined height, extends forward, and its front end bends upward. The support frame 1123 is composed of, for example, 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 surface inside the main frame 1121. The support frame 1123 forms a basket storage area on its upper side.

[0016] The front connecting section 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.

[0017] The mounting portion 1125 has its upper end fixed to a predetermined location on the support frame 1123. The mounting portion 1125 extends downward from the support frame 1123, bends backward at a predetermined height, and extends backward. The mounting portion 1125 is a frame member for mounting the power receiving device 23. The mounting portion 1125 extends along a plane parallel to the floor on the inside of the main frame 1121 and forms a support surface that supports the power receiving device 23 on the underside of the support frame 1123. For example, the dimensions of the mounting portion 1125 are set such that when the cart 2 is installed on the cart base 3, the power transmission device 35 provided on the cart base 3 and the power receiving device 23 provided on the mounting portion 1125 are positioned opposite each other at a predetermined distance.

[0018] The horizontal frame section 113 comprises a plurality of link frames 1131, 1132, and 1133 that extend in the width direction, spanning between the left and right vertical frame sections 111.

[0019] The handle portion 114 is disposed above the rear end portion of the cart 2. The handle portion 114 is continuously arranged at the upper end portion of the vertical frame portion 111. As an example, the handle portion 114 extends in the width direction.

[0020] The mounting frame 115 is connected to the vertical frame portion 111. The mounting frame 115 extends above, for example, one vertical frame portion 111 and supports various electronic devices 21.

[0021] In the frame 11, the basket portion 12 is supported by the vertical frame portion 111, and front wheel casters 151 and rear wheel casters 152 are provided at the front end portion and the rear end portion of the lower frame portion 112 disposed below the basket portion 12, respectively. Also, in the frame 11, a power receiving device 23 is provided at a mounting portion 1125 which is a frame member of the lower frame portion 112 arranged along the floor surface. Further, a battery box 223 is provided on the vertical frame portion 111. For example, the battery box 223 is supported by a pair of sub - frames 1112 of the vertical frame portion 111.

[0022] Also, in the lower frame portion 112, the pair of main frames 1121 extend obliquely forward toward the center so that the interval in the width direction at the front side is narrowed. Therefore, the frame 11 is formed such that the width at the front side is narrow and the width at the rear side is wide in the forward direction of the cart 2.

[0023] The basket portion 12 is configured in a box shape that opens upward by, for example, a perforated panel member or a mesh - shaped wire member. The basket portion 12 is disposed at a height spaced above the floor surface in front of the vertical frame portion 111. The left and right sides of the rear end portion of the basket portion 12 are supported by the vertical frame portion 111.

[0024] The front caster 151 and rear caster 152 each include a wheel 153 that rotates in the direction of movement and a bracket portion 154 that rotatably supports the wheel 153. The bracket portion 154 is rotatably mounted to the frame 11. The cart 2 moves as the wheel 153 of the caster 15 rotates on the floor surface. In addition, the direction of travel of the cart 2 can be changed by rotating the bracket portion 154 of the caster 15.

[0025] Similar to the shape of the frame 11 and the basket section 12, the front wheel casters 151 are positioned so that they are narrower in width from side to side than the rear wheel casters 152. Therefore, when storing multiple carts 2 in a row, for example, the frame 11 of the rear cart 2 can be stored so that it overlaps with the frame 11 of the front cart 2.

[0026] The electronic device 21 is an information terminal such as a tablet device for providing information to the user, or a product reader for acquiring information on products selected by the user. The electronic device 21 is connected to a battery 22, for example, and is powered by the battery 22. The electronic device 21 may also be a charging device for charging electronic devices such as mobile phones, smartphones, and digital cameras owned by the user using the power from the battery 22.

[0027] In this embodiment, for example, the electronic device 21 is shown to include a tablet terminal 211 and a product reader 212. The tablet terminal 211 is a computer having a display unit equipped with a touch panel. The tablet terminal 211 is installed so that its display unit faces the user located on the handle unit 114 side. The tablet terminal 211 displays, for example, product information read by the product reader 212. The tablet terminal 211 may also perform settlement processing for products read by the product reader 212.

[0028] The product reader 212 is a device that reads product information. The product reader 212 may also have a display unit that displays the information of the product it has read. For example, the product reader 212 is an RFID tag reader that reads RFID tags attached to products that are placed in and taken out of the basket 12. Alternatively, the product reader 212 may be a scanner that reads product identification information such as barcodes attached to products.

[0029] Furthermore, the electronic device 21 may be an interface device for connecting a mobile device (smartphone, tablet, etc.) owned by the user, instead of the tablet device 211. The mobile device connected to the interface device as electronic device 21 may perform the same processing as the tablet device 211 described above. In addition, the interface device as electronic device 21 may charge the battery of the mobile device. Furthermore, the interface device as electronic device 21 may have a built-in battery 22, or it may connect to a separately provided battery 22.

[0030] The battery box 223 is mounted on the frame 11. The battery box 223 is fixed and supported, for example, by a pair of subframes 1112 located below the opening / closing panel 121 of the basket section 12. The battery 22 is a power supply unit that supplies power to the electronic equipment 21 mounted on the cart 2, and comprises a charging circuit 221 and a battery pack 222. The battery 22 is connected to a power receiving device 23 and is charged by the power receiving device 23.

[0031] The charging circuit 221 supplies power from the load circuit 2325 of the power receiving device 23 to the battery pack 222 as charging power (charging power). For example, the charging circuit 221 converts the power supplied from the load circuit 2325 into a DC current (charging power) used to charge the battery pack 222. That is, the charging circuit 221 converts the power from the load circuit 2325 into charging power with predetermined current and voltage values ​​for charging the battery pack 222 and supplies it to the battery pack 222. The charging circuit 221 charges the battery pack 222 with power from the power receiving device 23.

[0032] The battery pack 222 is charged by the 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.

[0033] The power receiving device 23 receives power transmitted wirelessly and supplies the received power to the electronic device 21 or the battery 22. The power receiving device 23 may also be configured to include an output terminal for supplying power to the electronic device 21. In this case, the battery 22 may be charged by the power supplied via the electronic device 21.

[0034] As shown in Figure 2, the power receiving device 23 is located at the bottom of the cart 2. The power receiving device 23 is positioned, for example, below the lower frame portion 112. When 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.

[0035] As shown in Figures 3 and 5, the power receiving device 23 includes, for example, a casing 230, a power receiving coil 231, and a power receiving board 232.

[0036] The casing 230 houses the power receiving coil 231 and the power receiving board 232 inside. The casing 230 is connected, for example, below the lower frame portion 112. Specifically, the casing 230 is fixed to the mounting portion 1125 of the lower frame portion 112.

[0037] The underside of the casing 230 is positioned on the cart 2 in a orientation that conforms to the floor surface on which the cart 2 travels. When multiple carts 2 are stacked and stored in a cart base 3, the casing 230 is shaped so that it does not overlap with the casing 230 of the power receiving devices 23 of adjacent carts 2 in the direction of travel. Furthermore, when multiple carts 2 are stacked and stored in a cart base 3, the casing 230 is positioned so as not to overlap with or interfere with the power receiving devices 23 of adjacent carts 2 in the direction of travel.

[0038] The power receiving coil 231 is placed inside the casing 230. The power receiving coil 231 is, for example, a planar coil formed by winding Litz wire. Alternatively, the power receiving coil 231 is, for example, a planar coil with a coil pattern formed on a printed circuit board. The power receiving coil 231 has, for example, a power receiving surface that is formed in a planar shape. The power receiving surface of the power receiving coil 231 is positioned facing the floor surface on which the cart 2 travels. Note that the power receiving coil 231 is not limited to a planar coil as long as it can transmit power to the power transmission device 35.

[0039] When the power receiving device 23 faces the power transmitting device 35, the power receiving coil 231 is electromagnetically coupled with 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.

[0040] The power receiving coil 231 is connected in series with the capacitor 2321 of the power receiving board 232, which will be described later. By being connected to the capacitor 2321, the power receiving coil 231 constitutes a power receiving resonant circuit (resonant element) 239.

[0041] Here, the receiving resonant circuit 239, composed of the receiving coil 231 and the capacitor 2321, functions as an AC power source that supplies AC power to the rectifier circuit 2322 connected to the receiving resonant circuit 239. For example, when using a magnetic field resonance method for power transmission, it is desirable that the resonant frequency of the receiving resonant circuit 239, composed of the receiving coil 231 and the capacitor 2321, be the same as, or nearly the same as, the resonant frequency of the transmitting resonant circuit 359, composed of the transmitting coil 351 and the capacitor 3521, which will be described later in the power transmission device 35. This improves the power transmission efficiency when the receiving resonant circuit and the transmitting resonant circuit are electromagnetically coupled.

[0042] Furthermore, when using an electromagnetic induction method for power transmission, the power receiving resonant circuit 239 may not have a capacitor 2321 and may be composed of a power receiving coil 231.

[0043] 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. By mounting electronic components and wiring patterns, for example, the power receiving board 232 can be 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, and the communication circuit 2327.

[0044] Capacitor 2321 is a resonant capacitor. 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 composed of multiple diodes. A pair of input terminals of the rectifier bridge are connected to the power receiving resonant circuit 239. The rectifier circuit 2322 outputs DC power from a pair of output terminals by full-wave rectifying the AC power supplied from the power receiving resonant circuit 239. The rectifier circuit 2322 supplies the DC power to the voltage conversion circuit 2323.

[0045] 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, for example, to the rectifier circuit 2322 and the switching circuit 2324 (load circuit 2325). This 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. This voltage conversion circuit 23232 converts the DC power supplied from the rectifier circuit 2322 into DC power suitable for operating the control circuit 2326.

[0046] The switching circuit 2324 switches the connection and disconnection of the voltage conversion circuit 23231 and the load circuit 2325. The switching circuit 2324 switches the 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.

[0047] 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, the charging circuit 221 that charges power to the battery pack 222. The load circuit 2325, together with the charging circuit 221, performs a charging process to store DC power of the voltage generated by the voltage conversion circuit 23231 in the battery pack 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 perform the function of the load circuit 2325. Also, if the power receiving device 23 is configured to have output terminals that supply power to electronic equipment 21, the power receiving device 23 may not have the load circuit 2325. In other words, although this embodiment describes a configuration in which the power receiving device 23 has a load circuit 2325, it is also possible to provide the load circuit 2325 outside the power receiving device 23 and connect the switching circuit 2324 of the power receiving device 23 to the externally provided load circuit via a connector or the like.

[0048] 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 memory. The processor performs arithmetic processing. The processor performs various processing based on the program and data used in the program stored in the memory. The memory stores the program and data used in the program, etc. The control circuit 2326 may be composed of a microcontroller and / or an oscillator circuit, etc.

[0049] The communication circuit 2327 communicates information regarding power transmission and reception with the power transmission device 35 via contactless means.

[0050] As shown in Figures 1 and 2, cart 2 is stored in a cart base 3 located at a predetermined storage position. In Figures 1 and 2, multiple carts 2 are stored in the cart base 3 in a nested manner.

[0051] The cart base 3, which serves as a storage device for cart 2, comprises a guide base 31 as a base section, a cart gate 32, and a plurality of power transmission devices 35 supported by the guide base 31.

[0052] The guide base 31 includes a plate-shaped support base 311 that is laid at a predetermined storage position. The support base 311 has a plurality of guide rails 312 extending in one direction on its upper surface, 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 guides the direction of travel of the carts 2 on the support base 311 by defining the movement of the front and rear wheels 153 with the guide rails 312 and guide grooves 313. The guide base 31 also supports a plurality of power transmission devices 35 at equal intervals.

[0053] The cart gate 32 comprises a pair of poles 322 erected from both sides of the guide base 31, and side bars 323 positioned at a predetermined height on both side edges of the guide base 31 and extending in one direction.

[0054] Multiple power transmission devices 35 are provided between a pair of guide grooves 313 in a guide base 31, which guides the pair of front wheels 153 of the cart 2. The multiple power transmission devices 35 are arranged in the direction of extension of the pair of guide grooves 313 in the guide base 31. Here, the direction of extension of the guide grooves 313 is the direction of travel of the cart 2 on the guide base 31. In other words, the direction of extension of the guide grooves 313 is the direction in which the multiple carts 2 are stacked on the guide base 31. The multiple power transmission devices 35 face the power receiving devices 23 of the multiple carts 2 that are stacked and stored on the cart base 3. The power transmission devices 35 transmit power to the power receiving devices 23 of the opposing carts 2 without contact.

[0055] As shown in Figures 3 to 5, the power transmission device 35 includes, for example, a casing 350, a power transmission coil 351, a power transmission board 352, a fan 353, and an AC adapter 354.

[0056] The casing 350 is formed, for example, in the shape of a rectangular box. The casing 350 houses the power transmission coil 351, the power transmission board 352, and the fan 353 inside. The casing 350 faces the power receiving device 23 of the cart 2, which is housed in the cart base 3, at a predetermined distance apart. The distance between the casing 350 and the casing 230 of the power receiving device 23 is several millimeters, specifically, for example, 1 mm to 10 mm.

[0057] 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 that are continuous with the bottom wall 3501 and the top wall 3502.

[0058] For example, a power transmission board 352 is placed on the bottom wall 3501. For example, a power transmission coil 351 is fixed to the top wall 3502. In the position where the power transmission device 35 is installed on the cart base 3, the upper surface of the top wall 3502 extends, for example, along the direction of travel of the cart 2. For example, the upper surface of the top wall 3502 extends horizontally. An exhaust port 3505 is formed on the top wall 3502 at a position on the central side of the top wall 3502 and opposite the central side of the power transmission coil 351 fixed to the top wall 3502. The exhaust port 3505 is composed of, for example, a plurality of openings 3506 formed in the top wall 3502.

[0059] The openings 3506 are formed in various shapes such as circular, rectangular, and arc-shaped. Multiple openings 3506 are positioned so that the air discharged from the multiple openings 3506 and in contact with the casing 230 of the power receiving device 23 facing the power transmission device 35 can move to the area of ​​the upper wall 3502 where the power transmission coil 351 is provided. Multiple openings 3506 are arranged intermittently in an annular shape such as circular, elliptical, or rectangular.

[0060] Of the four side walls 3503, at least one side wall 3503 has an air intake port 3507 formed in it for introducing outside air into the casing 350.

[0061] A predetermined gap is formed between the bottom wall 3501 and the top wall 3502 of such a casing 350. Here, the predetermined gap between the bottom wall 3501 and the top wall 3502 is the distance between the opposing bottom wall 3501 and top wall 3502 that allows airflow to be formed from the intake port 3507 formed in the side wall 3503 to the exhaust port 3505. Specifically, the bottom wall 3501 and the top wall 3502 are separated by a width that allows airflow to be formed between the power transmission board 352 located on the bottom wall 3501 and the power transmission coil 351 located on the top wall 3502. For example, the width of the gap between the power transmission board 352 located on the bottom wall 3501 and the power transmission coil 351 located on the top wall 3502 is several centimeters, and specifically, for example, 1 cm to 10 cm.

[0062] The power transmission coil 351 is, for example, a planar coil formed by winding Litz wire. Alternatively, the power transmission coil 351 is, for example, a planar coil in which a coil pattern, or windings, are formed on a printed circuit board. The power transmission coil 351 has, for example, a power transmission surface formed in a planar shape for transmitting power.

[0063] The power transmission surface of the power transmission coil 351 is positioned along the floor surface on which the cart 2 travels. The power transmission surface of the power transmission coil 351 is also positioned along the power receiving surface of the power receiving coil 231 housed in the cart base 3 and provided on the opposing cart 2. Each power transmission coil 351 of the multiple power transmission devices 35 is positioned opposite the power receiving coil 231 of each power receiving device 23 of the multiple carts 2 housed in the cart base 3.

[0064] As a specific example, the power transmission coil 351 has, for example, an opening 3511 formed on its central side. The power transmission coil 351 is positioned on the upper wall 3502 of the casing 350 such that the center of the power transmission coil 351 is either the center of the upper wall 3502 or on the central side of the upper wall 3502. The opening 3511 of the power transmission coil 351 faces the exhaust port 3505 formed in the upper wall 3502. This allows the internal space of the casing 350 to communicate with the exhaust port 3505 in the upper wall 3502.

[0065] When the power receiving device 23 and the power transmitting device 35 are facing each other, the power transmission coil 351 is electromagnetically coupled with the power receiving coil 231.

[0066] The power transmission coil 351 is connected in series with the capacitor 3521 of the power transmission board 352, which will be described later. The power transmission coil 351, when connected to the capacitor 3521, constitutes a power transmission resonant circuit (resonant element) 359.

[0067] Here, it is desirable that the resonant frequency of the power transmission resonant circuit 359, which is composed of the power transmission coil 351 and the capacitor 3521, be the same as, or approximately the same as, the oscillation frequency of the oscillation circuit of the control circuit 3528. Note that when using an electromagnetic induction method for power transmission, the power transmission resonant circuit 359 may be composed solely of the power transmission coil 351, without the capacitor 3521.

[0068] 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. By mounting electronic components and wiring patterns, for example, the power transmission board 352 can be configured to include various processing circuits, such as 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, and the communication circuit 3529.

[0069] The capacitor 3521, together with the power transmission coil 351, forms a resonant circuit.

[0070] The power transmission circuit 3522 generates power to be transmitted and supplies the generated power to the power transmission coil 351. For example, the power transmission circuit 3522 generates AC power as power to be transmitted by switching DC power supplied via an AC adapter 354 or the like, based on the control of the control circuit 3528. The power transmission coil 351 outputs power that the power receiving device 23 can receive according to the power to be transmitted supplied from the power transmission circuit 3522. The power transmission circuit 3522 generates AC power with a frequency that is the same as, or approximately the same as, the resonant frequency of the power transmission resonant circuit 359. The power transmission circuit 3522 has a switching element such as an FET. The power transmission circuit 3522 is switched on and off by the output of the oscillation circuit in the control circuit 3528. The power output from the power transmission circuit 3522 is transmitted to the power receiving device 23 using electromagnetic coupling such as electromagnetic induction or magnetic field resonance between the power transmission coil 351 and the power receiving coil 231.

[0071] The voltage conversion circuit 3523 converts the voltage of a DC power supply, such as an AC adapter 354 connected to a commercial power supply, into a desired DC voltage. Specifically, the voltage conversion circuit 3523 generates power to operate the control circuit 3528 and supplies it to the control circuit 3528.

[0072] The switching circuit 3524 switches the connection and disconnection of the AC adapter 354 and the power transmission circuit 3522. Based on a control signal from the control circuit 3528, the switching circuit 3524 switches the power supply state from the power transmission device to the power receiving device by connecting or disconnecting the AC adapter 354 and the power transmission circuit 3522. For example, the switching circuit 3524 supplies either DC power at a voltage supplied from an external DC power source or DC power at a voltage stepped down by the voltage conversion circuit 3523 from the DC power supplied from the external DC power source to the power transmission circuit 3522. The switching circuit 3524 switches the DC power supplied to the power transmission circuit 3522 based on the control of the control circuit 3528.

[0073] The current sensor 3526 detects the DC current input to the power transmission circuit 3522. The current sensor 3526 is a small resistor connected between the switching circuit 3524 and the power transmission circuit 3522. The current sensor 3526 generates a potential (current detection signal) corresponding to the current transmitted from the switching circuit 3524 to the power transmission circuit 3522.

[0074] The current detection circuit 3527 amplifies the minute signal detected by the current sensor 3526 and outputs it to the control circuit 3528.

[0075] The control circuit 3528 controls the operation of the power transmission circuit 3522. The control circuit 3528 is a processing circuit. The control circuit 3528 includes, for example, a processor and memory. The processor performs arithmetic processing. The processor performs various processing based on programs and data used in programs stored in memory. The memory stores programs and data used in programs, etc. The control circuit 3528 may be composed of a microcontroller and / or an oscillator circuit, etc.

[0076] For example, the control circuit 3528 controls the frequency of the AC power output from the power transmission circuit 3522, and controls the on / off operation of the power transmission circuit 3522. For example, the control circuit 3528 switches between a state in which a magnetic field is generated in the power transmission coil 351 (power transmission state) and a state in which a magnetic field is not generated in the power transmission coil 351 (standby state) by controlling the switching circuit 3524. Alternatively, the control circuit 3528 may be configured to intermittently generate a magnetic field in the power transmission coil 351 to change the timing of power transmission.

[0077] When the power receiving device 23 is positioned opposite the power transmitting device 35, the control circuit 3528 first performs an authentication process to confirm whether the power receiving device 23 is the legitimate power receiving device 23. After authentication is established, the control circuit 3528 transmits power from the power transmitting device 35 to the power receiving device 23 and proceeds to the charging operation.

[0078] For example, the memory of the control circuit 3528 stores the current value that flows when a metal foreign object 99 of a predetermined size, made of a metal material, is located between the power transmission coil 351 and the power receiving coil 231, using the current value as a threshold value.

[0079] Here, the metallic foreign object 99 is made of a metallic material, at least partially or entirely. The metallic foreign object 99 is located between the power receiving device 23 and the power transmitting device 35, and is present on the power transmitting coil 351, generating heat when the power transmitting coil 351 transmits power. Examples of metallic foreign objects 99 include coins, metal pieces, paper or resin films with metal films or foils such as aluminum, clips, hairpins, and various other items.

[0080] Furthermore, the metal foreign object 99 whose size allows the current value to flow, which is stored as a threshold, is, for example, a metal foreign object 99 whose maximum dimensions are larger than 3 cm.

[0081] The control circuit 3528 then 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 exceeds the threshold value or is otherwise different from the normal current value, the control circuit 3528 controls the switching circuit 3524 to put the power transmission coil 351 into a standby state where it does not generate a magnetic field.

[0082] Furthermore, the control circuit 3528 controls, for example, the driving and stopping of the fan 353. Specifically, the control circuit 3528 drives the fan 353 when the power transmission coil 351 is in the power transmission state. Also, the control circuit 3528 stops the fan 353 when the power transmission coil 351 is in the standby state.

[0083] The communication circuit 3529 communicates information regarding power transmission and power reception with the communication circuit 2327 of the power receiving device 23 via contactless communication.

[0084] The fan 353 is located inside the casing 350 and draws in air from the intake port 3507 and exhausts air from the exhaust port 3505. The fan 353 is, for example, located adjacent to the intake port 3507 and on the inner surface of the side wall 3503. Alternatively, the fan 353 may be located adjacent to the exhaust port 3505 and on the inner surface of the upper wall 3502, within the opening 3511 of the power transmission coil 351. The fan 353 is connected to, for example, the control circuit 3528, and its operation and stopping are controlled by the control circuit 3528.

[0085] The AC adapter 354 is located, for example, outside the casing 350 and connected to the power transmission board 352.

[0086] In the power supply system 1 having the power transmission device 35 configured in this way, a power transmission coil 351 is provided on the central side of the upper wall of the casing 350 of the power transmission device 35, which faces the power receiving device 23 with a predetermined gap between them. An opening 3511 is formed in the center of the power transmission coil 351, and the exhaust port 3505 of the upper wall 3502 faces the power transmission coil 351. As a result, when the fan 353 is driven, the airflow blown out from the exhaust port 3505 is blocked by the casing 230 of the power receiving device 23 above the upper wall 3502 and flows in the planar direction of the upper surface of the upper wall 3502. Therefore, even if a metallic foreign object 99 made of a metallic material heats up on the upper surface of the upper wall 3502 of the casing 350 of the power transmission device 35, it is discharged from the exhaust port 3505 and cooled by the airflow that flows in the planar direction of the upper wall 3502 due to the casing 230 of the power receiving device 23. In this way, even if the metal foreign object 99, which is made of a metal material, generates heat, the power transmission device 35 can cool the metal foreign object 99 and suppress the temperature rise of the metal foreign object 99. In addition, the airflow flowing in the planar direction of the upper wall 3502 can also move small or light metal foreign objects 99.

[0087] Furthermore, an exhaust port 3505 is formed in the upper wall 3502 opposite the central opening 3511 of the power transmission coil 351. As a result, the airflow of the air exhausted from the exhaust port 3505 moves in all directions in the planar direction. Therefore, the power transmission device 35 can cool the metal foreign object 99 regardless of its position on the upper wall 3502 relative to the power transmission coil 351.

[0088] Therefore, the power transmission device 35 and the power supply system 1 can suppress the temperature rise of the metal foreign object 99 even if it is present on the upper surface of the area where the horizontally extending power transmission coil 351 of the power transmission device 35 is located. The power transmission device 35 and the power supply system 1 prevent the metal foreign object 99 from being transmitted via non-contact transmission while its temperature has risen.

[0089] Furthermore, the control circuit 3528 can suppress the heating of a metal foreign object 99 by stopping power transmission when it detects a metal foreign object 99 of a predetermined size due to a change in the current flowing through the power transmission coil 351. In addition, the control circuit 3528 drives the fan 353 when the power transmission coil 351 is in the power transmission state, so that airflow is generated on the top surface of the power transmission device 35 only when there is a risk that the metal foreign object 99 will heat up due to the power transmission coil 351. As a result, the power transmission device 35 can reduce power consumption and suppress the generation of noise caused by driving the fan 353.

[0090] According to the power transmission device 35 and power supply system 1 of the above-described embodiment, the temperature rise of the metallic foreign matter 99 can be suppressed.

[0091] It should be noted that the embodiments are not limited to the examples described above. For example, in the example described above, the receiving coil 231 of the power receiving device 23 and the transmitting coil 351 of the power transmitting device 35 may each be configured to include, for example, a magnetic material laminated on a printed circuit board on which windings are formed. Furthermore, when a magnetic material is provided in the transmitting coil 351, at least the opening 3511 of the transmitting coil 351 connects the exhaust port 3505 of the upper wall 3502 and the internal space of the casing 350. For this reason, the magnetic material may have openings in the parts facing the exhaust port 3505 and the opening 3511. Alternatively, multiple magnetic materials may be provided at intervals so that they do not exist in the parts facing the exhaust port 3505 and the opening 3511.

[0092] In the example described above, the cart base 3 was configured to have multiple guide grooves 313 that guide the movement of the wheels 153 of the cart 2, but it is not limited to this configuration. The cart base 3 only needs to guide the cart 2 so that the power receiving coil 231 of the power receiving device 23 mounted on the cart 2 is in 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 so that each guide groove 313 guides the movement of all the wheels 153 of the cart 2, but rather so that some of the guide grooves 313 guide the movement of the wheels 153 on one side.

[0093] Furthermore, in the example described above, the power receiving device 23 of the power supply system 1, which supplies power wirelessly, was described using a shopping cart as an example. However, the cart 2 on which the power receiving device 23 is mounted is not limited to a shopping cart; for example, it could be a picking cart used in a warehouse, etc. Also, the application of the power supply system 1 is not limited to the cart 2, but can be applied to wireless power supply to various other terminals. In addition, for example, the shape and specific configuration of the cart 2 and cart base 3 are not limited to the above embodiment.

[0094] According to the power transmission device and power supply system of at least one embodiment described above, it is possible to suppress the temperature rise of metallic foreign matter, at least in part, which is formed of a metallic material.

[0095] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. The following is a description equivalent to the invention described in the original claims of this application. [1] A power transmission coil with an opening on the central side, A casing comprising an upper wall facing the power receiving device on which the power transmission coil is provided, and an exhaust port facing the opening of the power transmission coil formed in the upper wall, A fan provided inside the casing, A power transmission device equipped with the following features. [2] The power transmission device according to [1], wherein the exhaust port faces the power receiving device when power is transmitted between the power transmission coil and the power receiving device. [3] The power transmission device according to [1] or [2], wherein the casing has a surface facing the power receiving device that is aligned horizontally. [4] The power transmission device according to any one of [1] to [3], wherein the power transmission device drives the fan when power is transmitted by the power transmission coil and the power receiving device, and stops the fan when power transmission is stopped. [5] A cart base that accommodates multiple carts, comprising multiple power transmission devices according to any one of [1] to [4] arranged along the direction of travel of the carts, The power receiving device is located at the bottom of the cart and transmits power to the power transmission device, A power supply system equipped with the following features. [Explanation of Symbols]

[0096] 1...Power supply system, 2...Cart, 3...Cart base, 11...Frame, 12...Basket section, 15...Caster, 21...Electronic equipment, 22...Battery, 23...Power receiving device, 31...Guide base, 32...Cart gate, 35...Power transmitting device, 99...Metal foreign object, 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 TA, 153...Wheel, 154...Bracket, 211...Tablet terminal, 212...Product reader, 221...Charging circuit, 222...Battery pack, 223...Battery box, 230...Casing, 231...Power receiving coil, 232...Power receiving board, 239...Power receiving resonant circuit, 311...Support base, 312...Guide rail, 313...Guide groove, 322...Pole, 323...Side bar, 350...Casing, 351...Power transmission coil, 352...Power transmission board, 353...F Fan, 354...AC adapter, 359...power transmission resonant circuit, 1111...main frame, 1112...subframe, 1113...subframe, 1121...main frame, 1123...support frame, 1124...front connecting section, 1125...mounting section, 1131...link frame, 1132...link frame, 1133...link frame, 2321...capacitor, 2322...rectifier circuit, 2323...voltage conversion circuit, 2324...switching circuit, 2 325...Load circuit, 2326...Control circuit, 2327...Communication circuit, 3501...Bottom wall, 3502...Top wall, 3503...Side wall, 3505...Exhaust port, 3506...Opening, 3507...Intake port, 3511...Opening, 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, 23231, 23232...Voltage conversion circuit.

Claims

1. A power transmission coil with an opening on the central side, A casing comprising a power transmission coil provided on the central side of the upper wall facing the power receiving device, and an exhaust port formed in the upper wall facing the opening of the power transmission coil, A fan provided inside the casing, Equipped with, An air intake port is formed in the side wall of the casing. The fan is provided adjacent to the air intake port and on the inner surface of the side wall, The exhaust port is formed by a plurality of openings arranged intermittently in an annular shape, in a power transmission device.

2. The power transmission device according to claim 1, wherein the exhaust port faces the power receiving device when power is transmitted between the power transmission coil and the power receiving device.

3. The power transmission device according to claim 1 or claim 2, wherein the casing has a surface facing the power receiving device that is aligned horizontally.

4. The power transmission device according to any one of claims 1 to 3, wherein the power transmission device drives the fan when power transmission is performed by the power transmission coil and the power receiving device, and stops the fan when power transmission is stopped.

5. A power transmission device according to any one of claims 1 to 4, wherein multiple power transmission devices are arranged in a cart base that accommodates multiple carts, along the direction of travel of the carts, The power receiving device is located at the bottom of the cart and transmits power to the power transmission device, A power supply system equipped with the following features.

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