Non-contact power receiving device

Abstract

To provide a non-contact power receiving device capable of suppressing variation in power transmission efficiency between a power receiving electrode and a power transmitting electrode.SOLUTION: A non-contact power receiving device is a non-contact power receiving device that is applied to a lower side of a vehicle body, and includes: a base member 32; an elastic member 34 that urges the base member toward the lower side; a rotating member 39 that is provided on the base member and comes into contact with the road surface 26; and a power receiving electrode 31 that is provided on the base member so as to face a road surface and receives supply of power in a non-contact manner from a power transmitting electrode 21 provided on the road surface. The power receiving electrode is fixed to the base member.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The disclosure in this specification relates to a power receiving device in a contactless power supply system. [Background technology]

[0002] Patent Document 1 discloses a conveying device that operates using contactless power supply using an electric field coupling method. This conveying device is configured so that a power transmitting electrode provided on the conveying path, such as a floor or a desk, is electrically coupled to a power receiving electrode provided on the bottom of the vehicle body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-168370 Summary of the Invention [Problem to be solved by the invention]

[0004] The conveying device described in Patent Document 1 had a problem in that if the floor surface was undulating or uneven, the distance between the power receiving electrode and the power transmitting electrode would fluctuate, causing fluctuations in the power transmission efficiency between the power receiving electrode and the power transmitting electrode.

[0005] One disclosed object is to provide a contactless power receiving device that can suppress fluctuations in power transmission efficiency between a power receiving electrode and a power transmitting electrode. [Means for solving the problem]

[0006] The non-contact power receiving device disclosed herein is a non-contact power receiving device attached to the underside of a vehicle body (11), and comprises a base member (32), an elastic member (34) that biases the base member downward, a rotating member (39) that is provided on the base member and contacts the road surface (26), and a power receiving electrode (31) that is provided on the base member so as to face the road surface and that receives power supply non-contact from a power transmitting electrode (21) that is provided on the road surface.

[0007] In the above configuration, the base member is biased downward by the elastic member, causing the rotating member provided on the base member to contact the road surface. The rotating member contacting the road surface maintains a constant distance between the base member and the road surface. This maintains a constant distance between the power receiving electrode provided on the base member and the power transmitting electrode provided on the road surface. Therefore, with the disclosed contactless power receiving device, the power transmission efficiency between the power receiving electrode and the power transmitting electrode is less likely to fluctuate. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a top view of a mobile robot. [Figure 2] FIG. 1 is a side view of a mobile robot. [Figure 3] FIG. 2 is a block diagram showing the configurations of a mobile robot, a power transmitting device, and a contactless power receiving device. [Figure 4] FIG. 2 is a side view of the contactless power receiving device. [Figure 5] FIG. 2 is a front view of the contactless power receiving device. [Figure 6] FIG. 10 is a front view of a non-contact power receiving device according to a modified example. [Figure 7] FIG. 10 is a front view of a non-contact power receiving device according to a modified example. [Figure 8] FIG. 10 is a top view of a contactless power receiving device according to a modified example. [Figure 9] FIG. 10 is a front view of a non-contact power receiving device according to a modified example. [Figure 10] FIG. 10 is a top view of a mobile robot according to a modified example. [Figure 11] FIG. 10 is a side view of a mobile robot according to a second embodiment. [Figure 12] FIG. 10 is a side view of a mobile robot according to a second embodiment. [Figure 13] FIG. 10 is a perspective view of a non-contact power receiving device according to a second embodiment. [Figure 14] FIG. 10 is a top view of a contactless power receiving device according to a second embodiment. [Figure 15] FIG. 10 is a side view of a contactless power receiving device according to a second embodiment. [Figure 16] FIG. 10 is a top view of a contactless power receiving device according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) The contactless power transfer system 1 includes a mobile robot 10, a power transmitting device 20, and a contactless power receiving device 30. The contactless power transfer system 1 transfers power from the power transmitting device 20 to the mobile robot 10 via the contactless power receiving device 30 in a contactless manner.

[0010] The contactless power receiving device 30 is a device that receives power contactlessly through electric field coupling. The contactless power receiving device 30 includes a power receiving electrode 31. The contactless power receiving device 30 receives power through electric field coupling between the power transmitting electrode 21 and the power receiving electrode 31. Details of the power transmitting electrode 21 and the power receiving electrode 31 will be described later. The contactless power receiving device 30 is attached to a mobile robot 10 for use, as shown in FIGS. 1 and 2.

[0011] <Mobile Robot 10> The mobile robot 10 is an AGV (Automated Guided Vehicle) that transports parts and products indoors in a building, such as a factory or warehouse. An AGV is an unmanned transport vehicle or robot. The mobile robot 10 moves along any transport route set up in the building. The contactless power receiving device 30 may be attached to an AGV used outdoors. The mobile robot 10 may also be an AMR (Autonomous Mobile Robot) or a mobile manipulator. An AMR is an autonomous mobile robot. A mobile manipulator is a robot that combines an AMR and a collaborative robot.

[0012] The mobile robot 10 moves on a road surface 26. The road surface 26 is the surface on which the mobile robot 10 moves. One example of the road surface 26 is a factory floor. The road surface 26 may be the surface of an outdoor road or the ground. A power transmitting electrode 21 is provided on the road surface 26. The mobile robot 10 receives power from the power transmitting electrode 21 via a power receiving electrode 31 provided on a wireless power receiving device 30. The mobile robot 10 moves based on the received power.

[0013] Although FIG. 1 is a top view, the power receiving electrode 31 and drive wheels 17 are indicated by solid lines to clearly show the relative positions of the components. As shown in FIGS. 1, 2, and 3, the mobile robot 10 includes a robot frame 11, a power receiving circuit 13, a power storage unit 14, a control unit 15, a drive unit 16, and multiple drive wheels 17. The robot frame 11 is a metal frame that forms the body of the mobile robot 10, i.e., the overall exterior shape of the mobile robot 10. The robot frame 11 includes a bottom 12. As shown in FIGS. 2 and 4, the bottom 12 is the lower portion of the body of the mobile robot 10. The bottom 12 includes a portion of the robot frame 11 that faces the road surface 26. The bottom 12 forms a bottom surface 12a, which is the lower surface of the bottom 12. The bottom surface 12a faces the road surface 26.

[0014] The power receiving circuit 13 is a circuit that rectifies the power received by the power receiving electrode 31. The power receiving circuit 13 has a rectifier circuit. The power receiving circuit 13 may have a function of matching impedance to the electrical characteristics of the power transmitting device 20 on the power transmitting side. For example, the power receiving circuit 13 may further include a matching circuit. The power rectified by the power receiving circuit 13 is output to the power storage unit 14. The power receiving circuit 13 may have a transformer circuit that transforms the power received by the power receiving electrode 31, i.e., the power rectified by the rectifier circuit, to a voltage suitable for storage. The transformer circuit may be, for example, a DC-DC converter. The power receiving circuit 13 may have a ground layer (not shown) connected to an electric wire or metal body that provides a ground potential. The ground for the power receiving circuit 13 may be the robot frame 11. The power storage unit 14 is a component that stores the power input from the power receiving circuit 13. The power storage unit 14 includes, for example, a battery or a capacitor.

[0015] The control unit 15 is configured to execute overall control of the mobile robot 10. The control unit 15 has a computer including, for example, a central processing unit (CPU), random access memory (RAM), and read-only memory (ROM). The control unit 15 executes a computer program using the CPU to control the overall control of the mobile robot 10. The control unit 15 controls the power supplied from the power storage unit 14 to the drive unit 16, and also controls charging of the power storage unit 14 from the power receiving electrode 31.

[0016] The driving unit 16 is a component that rotates and drives the driving wheels 17 to move the mobile robot 10 along the transport path. The driving unit 16 is, for example, a motor. The driving wheels 17 are wheels.

[0017] As shown in Figures 1 and 2, in this embodiment, the direction of travel of the mobile robot 10 is defined as the forward direction D1. The direction opposite to the forward direction D1 is defined as the backward direction D2. The direction from the bottom 12 of the mobile robot 10 toward the road surface 26 is defined as the downward direction D4. The direction opposite to the downward direction D4 is defined as the upward direction D3. The direction perpendicular to the direction of travel and the up-down direction is defined as the left-right direction. The left-right direction may be interpreted as the width direction of the mobile robot 10. The right direction D5 may be the direction that is east when the forward direction D1 is facing north. The left direction D6 is the opposite direction to the right direction D5.

[0018] <Power transmission device 20> The power transmitting device 20 is a device that wirelessly supplies power to the contactless power receiving device 30. The power transmitting device 20 is installed in a facility such as a factory or a warehouse. As shown in FIG. 3 , the power transmitting device 20 includes a power transmitting electrode 21, a high-frequency generating unit 22, a power source 23, a power transmitting circuit 24, and a control unit 25.

[0019] The power transmitting electrode 21 is an electrode that supplies power to the mobile robot 10 contactlessly by using electric field coupling with the power receiving electrode 31. The power transmitting electrode 21 is made of a conductive material (e.g., metal). The power transmitting electrode 21 is placed on the road surface 26, which is the floor surface of the floor 200. As shown in FIG. 1 , the power transmitter 20 includes two power transmitting electrodes 21 arranged substantially parallel to each other. Each power transmitting electrode 21 is a plate-shaped conductor and extends along the transport path. For convenience, in this disclosure, the power transmitting electrode 21 on the right side of the direction of travel is sometimes referred to as the right transmitting electrode, and the power transmitting electrode on the left side is sometimes referred to as the left transmitting electrode. The transport path is the path along which the mobile robot 10 travels. The transport path may be set to any path depending on the structure of the facility. The power transmitting electrodes 21 are arranged at a predetermined interval dis from each other in the left-right direction. The power transmitting electrodes 21 are not limited to being linear, and may have curved portions. The power transmitting electrode 21 is disposed so that its plate surface faces the bottom 12 of the mobile robot 10.

[0020] The high frequency generating unit 22 is a component that generates high frequency waves using power from the power supply 23. The high frequency generating unit 22 has, for example, an inverter. The high frequency waves generated by the high frequency generating unit 22 are supplied to the power transmitting electrode 21 through the power transmitting circuit 24. The power transmitting circuit 24 is a circuit that supplies the high frequency waves generated by the high frequency generating unit 22 to the power transmitting electrode 21. The power transmitting circuit 24 has, for example, a matching circuit and may be configured to match impedance in accordance with the electrical characteristics of the non-contact power receiving device 30 on the power receiving side.

[0021] A high-frequency signal generated by the high-frequency generating unit 22 is input to the power transmitting electrode 21 through the power transmitting circuit 24. Here, the power receiving electrode 31 is located above the power transmitting electrode 21, and when the power transmitting electrode 21 and the power receiving electrode 31 face each other, electric power is supplied from the power transmitting electrode 21 to the power receiving electrode 31 in a contactless manner by electric field coupling.

[0022] The control unit 25 is configured to execute overall control of the power transmitting device 20. The control unit 25 has a microcomputer including, for example, a CPU, RAM, and ROM. The control unit 25 executes a computer program on the CPU to execute overall control of the power transmitting device 20, including control of the high-frequency generating unit 22. The control unit 25 does not necessarily have to have a microcomputer. The control unit 25 may have an IC (Integrated Circuit) or the like instead of a microcomputer. The control unit 25 may be realized by an IC, an FPGA (Field-Programmable Gate Array), an SoC (System on a Chip), a microcomputer, or a combination thereof.

[0023] <Non-contact power receiving device 30> The contactless power receiving device 30 receives power through electric field coupling and supplies it to the mobile robot 10. The contactless power receiving device 30 is attached to the underside of the vehicle body (i.e., the mobile robot 10) as shown in FIGS. 4 and 5. The underside of the vehicle body is the underside of the robot frame 11. In this embodiment, the contactless power receiving device 30 is attached to the bottom 12 of the robot frame 11. The contactless power receiving device 30 includes a base member 32, a power receiving electrode 31, a ground plate 33, an elastic member 34, and a rotating member 39.

[0024] The base member 32 is a member that supports the power receiving electrode 31. The base member 32 is a dielectric. The base member 32 may be a dielectric with a relative dielectric constant of 5.0 or less. From the viewpoint of high efficiency, the base member 32 is preferably formed of a material with a small dielectric loss (dielectric loss tangent). The base member 32 may be formed using an insulating material with a dielectric loss tangent of 0.1 or less. For example, the material of the base member 32 may be polypropylene or the like. In this embodiment, as an example, the base member 32 also plays a role in supporting the ground plate 33.

[0025] In this embodiment, the base member 32 is plate-shaped with a rectangular plate surface. The shape of the base member 32 can be set arbitrarily. In other embodiments, the base member 32 may have a three-dimensional shape such as a cylinder, an elliptical cylinder, a polygonal prism, or a cube. The shape of the base member 32 is not limited to a plate-like shape as long as it can function to fix the position and orientation of the power receiving electrode 31 relative to the rotating member 39.

[0026] The upper surface of the base member 32 is referred to as the upper base surface. The upper base surface faces the bottom surface 12a. The lower surface of the base member 32 is referred to as the lower base surface. The lower base surface is configured to face the road surface 26 or the power transmitting electrode 21. The base member 32 is attached to the bottom 12 via an elastic member 34 so as to be approximately parallel to the power transmitting electrode 21. The thickness direction of the base member 32 is arranged so as to be approximately parallel to the up-down direction. A ground plate 33 is provided on the upper base surface. A power receiving electrode 31 is provided on the lower base surface. In other words, part or all of the base member 32 is sandwiched between the power receiving electrode 31 and the ground plate 33.

[0027] The power receiving electrode 31 is an electrode for receiving power from the power transmitting electrode 21 in a contactless manner using electric field coupling. The power receiving electrode 31 is formed of a conductive material (e.g., metal). The power receiving electrode 31 is a plate-shaped conductor. The power receiving electrode 31 may be a metallic film deposited by plating or the like on the lower surface of the base member 32. The power receiving electrode 31 is electrically connected to the power receiving circuit 13 using a cable or the like. The power receiving electrode 31 supplies the power received from the power transmitting electrode 21 to the power receiving circuit 13.

[0028] The power receiving electrode 31 is fixed to the base member 32 using any fixing method such as screws, adhesive, snap fit, or the like. The power receiving electrode 31 is formed on a portion of the base member 32 that is below the ground plate 33. For example, the power receiving electrode 31 is provided on the underside of the base. The power receiving electrode 31 may also be formed inside the base member 32. The underside of the power receiving electrode 31 is disposed so as to face the power transmitting electrode 21. The distance between the power receiving electrode 31 and the power transmitting electrode 21 is set to, for example, 10 mm or less, more preferably 5 mm or less. The distance between the power receiving electrode 31 and the power transmitting electrode 21 may be set to any value. The power receiving electrode 31 is disposed so as to be approximately parallel to the power transmitting electrode 21. The power receiving electrode 31 faces the power transmitting electrode 21 with a space formed between them.

[0029] The power receiving electrode 31 has a left power receiving electrode 31L and a right power receiving electrode 31R. The left power receiving electrode 31L is disposed to the left of the center of the base member 32 in the left-right direction. The right power receiving electrode 31R is disposed to the right of the center of the base member 32 in the left-right direction. The length (i.e., width) of the left power receiving electrode 31L and the right power receiving electrode 31R in the left-right direction is approximately equal to the length of the power transmitting electrode 21 in the left-right direction. A gap is provided between the left power receiving electrode 31L and the right power receiving electrode 31R. The distance between the left power receiving electrode 31L and the right power receiving electrode 31R is approximately equal to the distance dis between the power transmitting electrodes 21.

[0030] When the power receiving electrode 31 is formed on the underside of the base, a protective film may be attached to the surface of the power receiving electrode 31. The protective film may be a resin film that is permeable to electromagnetic waves. The protective film is an optional element. The protective film may have water-repellent properties, etc. A configuration in which a protective film is attached to the power receiving electrode 31 can reduce the risk of the power receiving electrode 31 itself deteriorating or the power supply efficiency deteriorating due to the adhesion of water droplets, etc. Note that, when the power receiving electrode 31 is formed inside the base member 32, the risk of the power receiving electrode 31 deteriorating, etc. can be reduced even without a protective film. Note that a protective film may also be attached to the power transmitting electrode 21.

[0031] The ground plate 33 is a conductive plate that functions as a ground (so-called GND). The ground plate 33 is made of a metal such as copper. The ground plate 33 may be a metallic film deposited by plating or the like on the surface of the base member 32. The plate-like shape of the ground plate 33 and the power receiving electrode 31 may also include a thin film shape. The ground plate 33 is electrically connected to the ground for the power receiving circuit 13 using a cable. The ground plate 33 is provided on the base member 32 above the power receiving electrode 31 so as to face the power receiving electrode 31. The ground plate 33 is disposed on the upper surface of the base member 32. The ground plate 33 is fixed to the base member 32. The ground plate 33 is sized to cover the power receiving electrode 31 in the front-rear and left-right directions.

[0032] The elastic member 34 is a member that biases the base member 32 in the downward direction D4. The elastic member 34 is, for example, a damper. The elastic member 34 may be any member that biases the base member 32 in the downward direction D4, and may be a metal compression coil spring. One end of the elastic member 34 is connected to the bottom surface 12a. The other end of the elastic member 34 is connected to the upper base surface of the base member 32. The elastic member 34 supports the base member 32. Four elastic members 34 are provided. One elastic member 34 is arranged at the front, back, left and right (i.e., at the four corners) of the base member 32. The number and arrangement of the elastic members 34 may be set arbitrarily.

[0033] The rotating member 39 is provided on the base member 32 and rotates in contact with the road surface 26. The rotating member 39 is fixed to the base member 32. The rotating member 39 has a pair of extensions 35, an axle 36, and a rotating body 37. The extensions 35 are members that support the axle 36 and the rotating body 37. The shape of the extensions 35 may be any shape.

[0034] The rotating body 37 is a wheel. The rotating body 37 is rotatably supported on an axle 36. The rotation of the rotating body 37 enables the contactless power receiving device 30 to move on the road surface 26. The rotating body 37 is biased in the downward direction D4 by the elastic member 34, and is thereby in contact with the road surface 26. The rotating body 37 is biased in the downward direction D4 by the elastic member 34, and is thereby kept in contact with the road surface 26 even if the road surface 26 is undulating or has unevenness.

[0035] Four rotating members 39 are provided. One rotating member 39 is arranged on the front, rear, left and right sides of the base member 32. The number of rotating members 39 may be any number. The rotating members 39 are arranged at positions that overlap with the elastic members 34 in the front-rear and left-right directions. The arrangement of the rotating members 39 may be any number.

[0036] The rotating body 37 of the rotating member 39 that faces forward (D1) and leftward (D6) on the mobile robot 10 is referred to as the left front wheel 37Lf. The rotating body 37 of the rotating member 39 that faces forward (D1) and rightward (D5) on the mobile robot 10 is referred to as the right front wheel 37Rf. The rotating body 37 of the rotating member 39 that faces backward (D2) and leftward (D6) on the mobile robot 10 is referred to as the left rear wheel 37Lb. The rotating body 37 of the rotating member 39 that faces backward (D2) and rightward (D5) on the mobile robot 10 is referred to as the right rear wheel 37Rb. Note that in this embodiment, the rotating members 39 and the elastic members 34 are arranged at the four corners of the base member 32, but the arrangement of the rotating members 39 and the elastic members 34 is not limited thereto. Three rotating members 39 and three elastic members 34 may be distributed around the base member 32, as in a tricycle. In this case, one wheel may pass over the power transmitting electrode 21. Therefore, it is preferable that a protective film be provided on the power transmitting electrode 21.

[0037] <Operation of the First Embodiment> The distance between the power receiving electrode 31 and the power transmitting electrode 21 is referred to as the transmitting / receiving distance S1. The distance between the power receiving electrode 31 and the ground plate 33 is referred to as the ground distance S2. The distance between the power receiving electrode 31 and the bottom surface 12a is referred to as the frame distance S3. The distance between the bottom surface 12a and the road surface 26 is referred to as the bottom distance S4.

[0038] The base member 32 is biased in the downward direction D4 by the elastic member 34, and the rotating member 39 (rotating body 37) provided on the base member 32 comes into contact with the road surface 26. The rotating body 37 in contact with the road surface 26 keeps the distance between the base member 32 and the road surface 26 constant. The distance between the base member 32 and the road surface 26 is approximately the same as the length of the rotating member 39 in the vertical direction.

[0039] The power receiving electrode 31 is fixed to a base member 32. Therefore, the distance between the base member 32 and the road surface 26 is kept constant, and therefore the transmission / reception interval S1 is also kept constant. In addition, the ground interval S2 is approximately the same as the plate thickness of the base member 32. Therefore, the ground interval S2 is also kept constant.

[0040] If the road surface 26 is undulating or uneven, the bottom surface distance S4 will fluctuate. Even in this case, the transmission / reception distance S1 and the ground distance S2 are kept constant as described above. Therefore, the power transmission efficiency between the power receiving electrode 31 and the power transmitting electrode 21 can be kept constant.

[0041] On the other hand, if the bottom surface distance S4 varies, the elastic member 34 deforms, and the frame distance S3 also varies. In other words, since the transmitting / receiving distance S1 and the ground distance S2 are constant, if the bottom surface distance S4 varies, the frame distance S3 also varies by the amount of the variation. If the ground plate 33 were not provided, the bottom 12 would essentially act as a ground when viewed from the power receiving electrode 31, and the characteristic impedance between the power receiving electrode 31 and the ground would vary in conjunction with the variation in the frame distance S3. In other words, if the ground plate 33 were not provided, the input impedance of the power receiving system as viewed from the power transmitting system would vary depending on the shape of the road surface 26 (effectively, the change in the frame distance S3), which could degrade power transmission efficiency.

[0042] To address this issue, in this embodiment, a ground plate 33 is provided on the upper surface of the base member 32, so that the ground spacing S2, and therefore the characteristic impedance between the power receiving electrode 31 and the ground, is kept constant even if the frame spacing S3 varies. This makes it possible to keep the input impedance of the power receiving system (non-contact power receiving device 30) constant (i.e., at an expected value) as seen from the power transmission system (power transmitting device 20). This improves the stability of the power transmission efficiency between the power receiving electrode 31 and the power transmitting electrode 21.

[0043] The bottom 12 of the vehicle body and the base member 32 are connected via an elastic member 34. In this embodiment, the base member 32 is a plate-shaped dielectric. This ensures insulation between the robot frame 11 (bottom surface 12a) and the power receiving electrode 31, even if the elastic member 34 is made of metal. The base member 32 does not have to be plate-shaped.

[0044] In the present disclosure, the dielectric loss tangent of the base member 32 is 0.1 or less, which can reduce the dielectric loss caused by the base member 32.

[0045] In the present disclosure, a left front wheel 37Lf, a left rear wheel 37Lb, a right front wheel 37Rf, and a right rear wheel 37Rb are provided as the rotating members 39. This allows the non-contact power receiving device 30 to move stably.

[0046] <Variation 1> In the above-described embodiment, a single base member 32 supports the left power receiving electrode 31L and the right power receiving electrode 31R, but this is not necessarily limited to this. For example, as shown in FIG. 6, the base member 32 may be divided into two parts, left and right. In this modification, the base member 32 has a left base portion 32L and a right base portion 32R. The left base portion 32L and the right base portion 32R will hereinafter be referred to as both base portions 32L and 32R.

[0047] Both base portions 32L, 32R are plate-shaped with rectangular plate surfaces. The shapes of both base portions 32L, 32R can be set arbitrarily. The shapes of both base portions 32L, 32R may be flat, cylindrical, elliptical, polygonal, cubic, or the like. The shapes of both base portions 32L, 32R may be different from each other. A gap is provided between the left base portion 32L and the right base portion 32R.

[0048] The left power receiving electrode 31L is fixed to the left base portion 32L, and the right power receiving electrode 31R is fixed to the right base portion 32R.

[0049] <Variation 2> In the above-described modified example, the contactless power receiving device 30 is attached to the mobile robot 10 as a single unit, but this is not necessarily limited to this. As shown in Fig. 7, the contactless power receiving device 30 may be divided into two parts in the left-right direction.

[0050] In this modification, the ground plate 33 includes a left ground plate 33L and a right ground plate 33R. The left ground plate 33L is disposed on the upper surface of the left base portion 32L so as to face the left power receiving electrode 31L. The right ground plate 33R is disposed on the upper surface of the right base portion 32R so as to face the right power receiving electrode 31R.

[0051] To stabilize the posture, each of the base portions 32L, 32R may be provided with four elastic members 34. The four elastic members 34 may be arranged at the front, back, left, and right (i.e., the four corners) of the base portions 32L, 32R so as to surround the left ground plate 33L or the right ground plate 33R.

[0052] In this modification, a gap is provided between the left base portion 32L and the right base portion 32R, which can prevent the left power receiving electrode 31L and the right power receiving electrode 31R from being coupled to each other.

[0053] In this modified example, the elastic members 34 are arranged on the front, back, left and right sides of both base portions 32L, 32R, but this is not necessarily limited to this. A configuration in which the rotation members 39 are arranged on the front, back, left and right sides of both base portions 32L, 32R may also be used. When the left base portion 32L has four rotation members 39, the elastic members 34 may be provided only on the front and back of the left base portion 32L (i.e., in two locations). A configuration similar to that of the left base portion 32L may also be applied to the right base portion 32R.

[0054] <Variation 3> In the second modification, the non-contact power receiving device 30 is shown separated into two parts, left and right, as an example of a configuration in which the ground plate 33 is divided into the left ground plate 33L and the right ground plate 33R. However, this is not necessarily limited to this. As shown in FIG. 8 , a single rectangular base member 32 may have a hole in its center. This configuration corresponds to the configuration in the second modification in which the left base portion 32L and the right base portion 32R are connected at their front and rear ends. FIG. 8 is a top view of the non-contact power receiving device 30, and the ground plate 33 is hatched for convenience in clearly showing the positional relationship of the components. The two separated left and right ground plates 33 are electrically connected by a cable (not shown) so that they are at the same potential. The elastic member 34 is also omitted in FIG. 8 . Even with this configuration, coupling between the left power receiving electrode 31L and the right power receiving electrode 31R can be suppressed.

[0055] In addition, as shown in FIG. 8 , by hollowing out the center of the base member 32, the amount of resin can be reduced, thereby reducing the weight of the contactless power receiving device 30. Furthermore, since the base member 32 is not completely separated into left and right halves, the position of the base member 32 relative to the road surface 26 can be stabilized by four (or three) rotating members 39 and four (or three) elastic members 34, as in the embodiment. In addition, in the configuration shown in FIG. 8 , unlike the configuration shown in FIG. 6 , one base member 32 functions as a member supporting the left and right ground plates 33 and the power receiving electrodes 31. Therefore, the ground plate 33 itself does not need to have strength, and the ground plate 33 does not need to be a metal plate with a certain rigidity. In the configuration shown in FIG. 8 , the ground plate 33 may be a conductive film or the like. In other words, the configuration shown in FIG. 8 can achieve even greater weight reduction compared to the configuration shown in FIG. 6 .

[0056] <Variation 4> 9, the ground plate 33 may be in the form of a thin film. The ground plate 33 may be formed on the upper surface of the base member 32 by vapor deposition on the base member 32. A conductive film (in other words, a conductive layer) serving as the ground plate 33 may be formed on the inside of the base member 32. If the ground plate 33 is formed in the form of a thin film, the weight of the contactless power receiving device 30 can be made lighter than if the ground plate 33 were a plate-like member having a thickness of several millimeters or more.

[0057] <Variation 5> In the above-described embodiment, the contactless power transfer system 1 has been shown to have two power transmitting electrodes 21 and two power receiving electrodes 31, but this is not necessarily limited to this. As shown in Fig. 10, the contactless power transfer system 1 may have a configuration including one power transmitting electrode 21 and one power receiving electrode 31. Fig. 10 is a top view, but for the sake of clarity, the power receiving electrode 31 and the drive wheels 17 are shown with solid lines to clearly show the positional relationship of the components. The contactless power transfer system 1 may have any number of power transmitting electrodes 21 and power receiving electrodes 31.

[0058] (Second embodiment) This embodiment may be considered a modification of the previous embodiment as a basic form. The description of the previous embodiment may be used to explain this embodiment. In the previous embodiment, the robot frame 11 was assumed to have a bottom 12, and the contactless power receiving device 30 was attached to the bottom 12 of the body. As in this embodiment, in other embodiments, the robot frame 11 does not need to have a bottom 12.

[0059] FIG. 11 shows a robot frame 11 according to this embodiment. The robot frame 11 has a shape in which a plurality of rod-shaped frames 111 are combined together. The robot frame 11 may have a shape in which a plurality of hexahedrons, each with an opening on each side, are connected together. Of the frames 111 constituting the robot frame 11, the frame 111 extending in the up-down direction is referred to as the vertical frame 111a. Of the frames 111, the frame 111 extending in the front-rear or left-right direction and disposed at the bottom is referred to as the lower frame 111b. In this embodiment, the contactless power receiving device 30 is attached to the lower end of the vertical frame 111a instead of the bottom 12. In other embodiments, the contactless power receiving device 30 may be attached to any frame 111 (for example, the lower frame 111b).

[0060] A drivetrain unit 100 is provided in the internal space of the robot frame 11. The drivetrain unit 100 is a component for driving the mobile robot 10. The drivetrain unit 100 includes a power receiving circuit 13, a power storage unit 14, a control unit 15, a drive unit 16, and a plurality of drive wheels 17. A portion of the drivetrain unit 100 may form the actual bottom surface 12a.

[0061] Fig. 12 shows the installation position of the contactless power receiving device 30. Fig. 12 corresponds to Fig. 2. The lower frame 111b is omitted in Fig. 12. As shown in Fig. 12, the robot frame 11 has an opening 111c that opens toward the road surface 26. The contactless power receiving device 30 is fixed to the vertical frame 111a. The contactless power receiving device 30 is disposed below the opening 11c.

[0062] FIG. 13 is a perspective view of the contactless power receiving device 30 according to this embodiment. The ground plate 33 and the support member 40 are omitted from FIG. 13. FIG. 14 is a top view of the contactless power receiving device 30 according to this embodiment. In FIG. 14, the support member 40 is hatched for the sake of convenience in clearly indicating the positional relationship of the components. FIG. 15 is a side view of the contactless power receiving device 30 according to this embodiment. In FIG. 15, the lower frame 111b is indicated by a dotted line for the sake of convenience in clearly indicating the positional relationship of the components.

[0063] In the preceding embodiment, the base member 32 played a role in supporting the ground plate 33, but in this embodiment, a support member 40 disposed on the power receiving electrode 31 plays a role in supporting the ground plate 33, separate from the base member 32. The base member 32 indirectly supports the ground plate 33 via the power receiving electrode 31 and the support member 40. As shown in FIGS. 13 and 14 , the base member 32 is divided into two parts, a front part and a rear part. For convenience, in this disclosure, the base member 32 disposed on the front side will be referred to as a front base portion 32f, and the base member 32 disposed on the rear side will be referred to as a rear base portion 32b.

[0064] The front base portion 32f may be plate-shaped with a rectangular plate surface. The shape of the front base portion 32f can be set arbitrarily. The shape of the front base portion 32f may be a flat plate, a cylindrical shape, an elliptical cylinder, a polygonal prism, a cube, or the like. The rear base portion 32b may have the same shape as the front base portion 32f. The front base portion 32f and the rear base portion 32b may have different shapes. Rotating members 39 are attached to both the left and right ends of the front base portion 32f and the rear base portion 32b. The front base portion 32f and the rear base portion 32b are connected by a power receiving electrode 31. The front base portion 32f and the rear base portion 32b are fixed to the robot frame 11 via an elastic member 34.

[0065] An arbitrary portion (for example, the upper portion) of the elastic member 34 is fixed to the vertical frame 111a. The upper portion of the elastic member 34 may be understood as a portion above the halfway point of the elastic member 34 in the vertical direction.

[0066] The rotating member 39 (and thus the rotating body 37) is provided at the left and right ends of the front base portion 32f and the rear base portion 32b. The extending portion 35 is fixed to the side surfaces of the front base portion 32f and the rear base portion 32b in the left-right direction. One end of the extending portion 35 is connected to the front base portion 32f and the rear base portion 32b. The extending portion 35 may extend from the base member 32 in the front-rear direction, for example.

[0067] The power receiving electrode 31 is fixed to the underside of the front base portion 32f and the rear base portion 32b. The power receiving electrode 31 is fixed to the front base portion 32f and the rear base portion 32b by screws, snap fit, etc. The power receiving electrode 31 may be fixed to the front base portion 32f and the rear base portion 32b by any method.

[0068] The contactless power receiving device 30 according to this embodiment includes a plurality of support members 40. The support members 40 are plate-shaped with rectangular plate surfaces. The support members 40 are dielectric. The support members 40 may be a dielectric with a relative dielectric constant of 5.0 or less. From the viewpoint of high efficiency, the support members 40 are preferably formed from a material with a small dielectric loss (dielectric loss tangent). The support members 40 may be formed from an insulating material with a dielectric loss tangent of 0.1 or less. The support members 40 may be made of the same material as the base member 32, or may be made of a different material.

[0069] The support member 40 is provided on the upper surface of the power receiving electrode 31. The support member 40 is provided to maintain a constant distance between the power receiving electrode 31 and the ground plate 33. The support member 40 is fixed to the upper surface of the power receiving electrode 31 with an adhesive or the like. The support member 40 is disposed between the power receiving electrode 31 and the ground plate 33. The support member 40 serves to support the ground plate 33 relative to the power receiving electrode 31. The plate surface of the support member 40 is set smaller than the plate surface of the power receiving electrode 31. The plate surface of the support member 40 is set smaller than the plate surface of the ground plate 33.

[0070] Two support members 40 are arranged on each of the power receiving electrodes 31R and 31L. The support members 40R and 40L are arranged on the power receiving electrodes 31R and 31L at a distance from each other in the front-to-rear direction. The left support portion 40L is sandwiched between the left power receiving electrode 31L and the left ground plate 33L. The right support portion 40R is sandwiched between the right power receiving electrode 31R and the right ground plate 33R. The support members 40 support the power receiving electrode 31 and the ground plate 33 so that they face each other. The support members 40 are arranged on the power receiving electrode 31 so that a gap is formed between the power receiving electrode 31 and the ground plate 33. A gap is provided between the left support portion 40L and the right support portion 40R.

[0071] The ground plate 33 has a left ground plate 33L, a right ground plate 33R, and an electric wire 331. The ground plate 33 is sized to cover the power receiving electrode 31 in the left-right direction when viewed from above. The ground plate 33 is sized larger than the power receiving electrode 31 in the left-right direction. The ground plate 33 is disposed to face the power receiving electrode 31 in an area above the power receiving electrode 31. The left ground plate 33L and the right ground plate 33R are electrically connected by an electric wire 331. The electric wire 331 is an electric wire for making the left ground plate 33L and the right ground plate 33R at the same potential. The electric wire 331 may be a copper wire. The electric wire 331 may be a cable with a core made of copper or the like.

[0072] In addition, one or both of the left ground plate 33L and the right ground plate 33R are electrically connected to the robot frame 11 using a cable 332. The robot frame 11 functions as the ground. For example, the ground plates 33L and 33R may be electrically connected to the lower frame 111b using the cable 332. The connection point between the cable 332 and the robot frame 11 may be any point.

[0073] <Operation of the Second Embodiment> The distance between the bottom surface of robot frame 11 and road surface 26 is referred to as bottom surface distance S4a. The bottom surface of robot frame 11 is, for example, the bottom surface of lower frame 111b. Bottom surface distance S4a corresponds to bottom surface distance S4.

[0074] In this embodiment, the robot frame 11 has an opening 11c, and the non-contact power receiving device 30 is disposed below the opening 11c. The non-contact power receiving device 30 is disposed facing a part of the drive train unit 100. Therefore, if the ground plate 33 were not present, the power receiving electrode 31 would face a part of the drive train unit 100. The part of the drive train unit 100 facing the power receiving electrode 31 is referred to as the facing part 100a. If the ground plate 33 were not present, the facing part 100a could be the closest metal body to the power receiving electrode 31.

[0075] The distance between the power receiving electrode 31 and the facing portion 100a is referred to as the member distance S3a. The member distance S3a substantially corresponds to the frame distance S3. If the road surface 26 has undulations or unevenness and the bottom surface distance S4 fluctuates, the elastic member 34 deforms, causing the member distance S3a to fluctuate. If the facing portion 100a is made of metal, the facing portion 100a can essentially act as a ground when viewed from the power receiving electrode 31. Therefore, as in the previous embodiment, the characteristic impedance between the power receiving electrode 31 and the ground can fluctuate in conjunction with the change in the member distance S3a as the bottom surface distance S4a fluctuates.

[0076] In other words, without the ground plate 33, the input impedance of the power receiving system as seen from the power transmitting system varies depending on the shape of the road surface 26 (actually, the change in the member spacing S3a), which can degrade the power transmission efficiency.

[0077] In this embodiment, as in the previous embodiment, a ground plate 33 is provided on the upper surface of the base member 32, so that the ground spacing S2 and therefore the characteristic impedance between the power receiving electrode 31 and the ground are kept constant even if the member spacing S3a varies. As a result, as in the previous embodiment, the input impedance of the power receiving system as seen from the power transmission system (power transmission device 20) can also be kept constant (i.e., an expected value). Therefore, the power transmission efficiency between the power receiving electrode 31 and the power transmitting electrode 21 can be kept constant.

[0078] Furthermore, in this embodiment, the support member 40 has a shape that forms a gap between the power receiving electrode 31 and the ground plate 33. Because a gap (i.e., air) is provided between the power receiving electrode 31 and the ground plate 33, this embodiment can suppress coupling between the power receiving electrode 31 and the ground plate 33 more effectively than a configuration in which the space between the power receiving electrode 31 and the ground plate 33 is filled with a dielectric.

[0079] Furthermore, in this embodiment, the left ground plate 33L and the right ground plate 33R are electrically connected by the electric wire 331, so that the left ground plate 33L and the right ground plate 33R are at the same potential. This allows the phases of the left ground plate 33L and the right ground plate 33R to be aligned, thereby improving power receiving efficiency.

[0080] <Modification> The support member 40 is not limited to a plate shape. The support member 40 may be a sponge-like member with many hollow portions formed therein, in which case the support member 40 may be larger than the power receiving electrode 31. The support member 40 may have a honeycomb structure. The support member 40 may be configured so that a gap is formed between the power receiving electrode 31 and the ground plate 33.

[0081] In the above embodiment, the contactless power receiving device 30 is attached to the mobile robot 10 as a single unit, but this is not necessarily limited to this. As shown in Fig. 16, the contactless power feeding device / contactless power receiving device 30 may be divided into two parts in the left-right direction.

[0082] In this modification, one front base portion 32f and one rear base portion 32b support one power receiving electrode 31L. One front base portion 32f and one rear base portion 32b support one power receiving electrode 31R. To stabilize the posture, two rotating members 39 may be provided on each of the front base portion 32f and the rear base portion 32b. Four rotating members 39 may be arranged on the front and rear base portions 32f, 32b so as to surround the power receiving electrode 31L or the power receiving electrode 31R.

[0083] In this modification, the rotating member 39 is disposed on the front and rear base portions 32f, 32b so as to surround the power receiving electrode 31R, but this is not necessarily limited to this. The rotating member 39 may be disposed on the front and rear base portions 32f, 32b so as to surround the power receiving electrode 31R.

[0084] In the above-described embodiment, the ground plate 33 is provided with the electric wire 331, but this is not necessarily limited to this. The ground plate 33 does not necessarily have to be provided with the electric wire 331.

[0085] (Other embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0086] Although the left-right length (i.e., width) of the left-side power receiving electrode 31L and the right-side power receiving electrode 31R is shown to be approximately equal to the left-side length of the power transmitting electrode 21, this is not necessarily limited to this. The left-side length (i.e., width) of the left-side power receiving electrode 31L and the right-side power receiving electrode 31R may be greater or smaller than the left-side length of the power transmitting electrode 21.

[0087] Although the configuration has been shown in which the distance between the left power receiving electrode 31L and the right power receiving electrode 31R is approximately equal to the distance dis between the power transmitting electrodes 21, this is not necessarily limited to this. The distance between the center in the left-right direction of the left power receiving electrode 31L and the center in the right-left direction of the power receiving electrode 31R is referred to as the power receiving electrode distance. The distance between the centers of the power transmitting electrodes 21 in the left-right direction is referred to as the power transmitting electrode distance. The power receiving electrode distance and the power transmitting electrode distance may be approximately the same value.

[0088] Although the mobile robot 10 has the power receiving circuit 13 in the above embodiment, this is not a limitation. The power receiving circuit 13 may also be provided in the non-contact power receiving device 30.

[0089] Although the base member 32 has a dielectric constant of 5.0 or less in the above embodiment, this is not necessarily limited to this. The base member 32 may be made of a material having any dielectric constant. The base member 32 may have a dielectric constant of 5.0 or more.

[0090] Although the configuration in which the ground plate 33 is provided on the upper surface of the base member 32 has been shown, this is not necessarily limited to this. The ground plate 33 does not necessarily have to be provided.

[0091] Although the contactless power receiving device 30 is configured to receive contactless power through electric field coupling in the above example, this is not necessarily limited to this. The contactless power receiving device 30 may be configured to receive contactless power through magnetic field coupling. The power receiving electrode 31 may be configured to receive power from the power transmitting electrode 21 in a contactless manner using magnetic field coupling.

[0092] Although the dielectric loss tangent of the support member 40 is 0.1 or less in the above embodiment, it is not necessarily limited to this. The dielectric loss tangent of the support member 40 may be 0.1 or more.

[0093] Although the ground plates 33L and 33R are electrically connected to the lower frame 111b using cables in the above embodiment, the present invention is not limited to this. The ground plates 33L and 33R may be electrically connected to the vertical frame 111a. The ground plates 33L and 33R may also be electrically connected to the elastic member 34.

[0094] (supplement) 3 does not show the entire configuration of the mobile robot 10, but may be interpreted as a diagram showing only a portion thereof. Similarly, FIG. 3 does not show the entire electrical configuration of the contactless power receiving device 30, but may be interpreted as a diagram showing only a portion thereof. Furthermore, the functional layout of the mobile robot 10 and the contactless power receiving device 30 can be changed as appropriate, and as described above, the power receiving circuit 13 may be provided in the contactless power receiving device 30. Furthermore, the control unit 15 and the power storage unit 14 may also be provided in part or in whole in the contactless power receiving device 30. [Explanation of symbols]

[0095] 10 Mobile robot, 11 Robot frame (body), 12 Bottom, 21 Power transmitting electrode, 26 Road surface, 31 Power receiving electrode, 31L Left side power receiving electrode, 31R Right side power receiving electrode, 32 Base member, 32L Left side base portion, 32R Right side base portion, 33 Ground plate, 34 Elastic member, 37Rf Right side front wheel, 37Lf Left side front wheel, 37Rb Right side rear wheel, 37Lb Left side rear wheel, 39 Rotating member, 40 Support member, 40L Left side support portion, 40R Right side support portion.

Claims

1. A contactless power receiving device attached to the underside of a vehicle body (11), a base member (32); an elastic member (34) that biases the base member downward; a rotating member (39) provided on the base member and in contact with the road surface (26); A contactless power receiving device comprising: a power receiving electrode (31) provided on the base member so as to face the road surface, and which receives power supply contactlessly from a power transmitting electrode (21) provided on the road surface.

2. The contactless power receiving device according to claim 1 , wherein the base member is a dielectric material.

3. The contactless power receiving device according to claim 2 , wherein the base member has a dielectric loss tangent of 0.1 or less.

4. the power receiving electrode is configured to receive power from the power transmitting electrode in a contactless manner using electric field coupling; The non-contact power receiving device according to claim 2, wherein a ground plate (33) is provided on the base member at a portion above the power receiving electrode so as to face the power receiving electrode.

5. the power receiving electrode is configured to receive power from the power transmitting electrode in a non-contact manner using electric field coupling; and a ground plate (33) arranged above the power receiving electrode so as to face the power receiving electrode; The contactless power receiving device according to claim 2 , further comprising: a support member (40) that is disposed between the power receiving electrode and the ground plate and is a dielectric material for supporting the ground plate relative to the power receiving electrode.

6. The contactless power receiving device according to claim 5 , wherein the support member has a shape that forms a gap between the power receiving electrode and the ground plate.

7. The power receiving electrodes include a left power receiving electrode (31L) and a right power receiving electrode (31R), 7. The contactless power receiving device according to claim 5, comprising a left front wheel (37Lf), a left rear wheel (37Lb), a right front wheel (37Rf), and a right rear wheel (37Rb) as the rotating members.

8. the power receiving electrode is configured to receive power from the power transmitting electrode in a contactless manner using electric field coupling; The power receiving electrodes include a left power receiving electrode (31L) and a right power receiving electrode (31R), The support member is a left support portion (40L) sandwiched between the left power receiving electrode and the ground plate; a right support portion (40R) sandwiched between the right power receiving electrode and the ground plate, The contactless power receiving device according to claim 5 , wherein a gap is provided between the left support portion and the right support portion.

Images