Contactless power supply device

Abstract

The present invention comprises: a fixed body (1001); a mobile body (1002) that is movably installed; a power transmission electrode (200) that is installed in the fixed body (1001); and a power reception electrode (300) that is installed in the mobile body (1002) and capacitively coupled to the power transmission electrode (200). The power transmission electrode (200) has a power transmission electrode tooth (220) and a power transmission electrode connection section (230). The power reception electrode (300) has a power reception electrode tooth (320) and a power reception electrode connection section (330). The power transmission electrode tooth (220) and the power reception electrode tooth (320) are separate from each other and face each other. A first capacitance and a second capacitance are formed in a region where the power transmission electrode tooth (220) and the power reception electrode tooth (320) face each other, and a third capacitance and a fourth capacitance are formed in a region where an end section of the power transmission electrode tooth (220) and the power reception electrode connection section (330) face each other and in a region where an end section of the power reception electrode tooth (320) and the power transmission electrode connection section (230) face each other. A dielectric is provided on a surface where the first to fourth capacitances are formed.

Description

Contactless power supply device

[0001] The present disclosure relates to a contactless power supply device.

[0002] Contactless power transfer using the capacitive coupling method is a technology that transmits power by forming a coupling capacitance between a power transmitting electrode and a power receiving electrode, which are made up of parallel plates. This technology is used for contactless power transfer in applications involving the movement of objects, such as electric vehicles and conveyance equipment that travel in specific lanes.

[0003] When using the electric field coupling method for contactless power supply to a moving object, the vibrations of the moving object that occur while it is moving cause the distance between the electrodes to change, which in turn changes the coupling capacitance, causing changes in power supply characteristics such as output voltage and making the system unstable. Ensuring a separation distance greater than necessary to prevent vibrations from the moving object improves stability against coupling capacitance, but reduces coupling capacitance. Therefore, to maintain high stability against changes in separation distance while ensuring high coupling capacitance, it is necessary to ensure a large facing area between the electrodes. However, this increases the size of each electrode, which creates the problem of an increased system size.

[0004] To solve this problem, a highly robust electrode member structure has been disclosed that includes a plate-shaped power transmitting electrode portion and a power receiving electrode portion that sandwiches the power transmitting electrode portion, thereby stabilizing the coupling capacitance against fluctuations in the separation distance.

[0005] Special Publication No. 6726081

[0006] However, the device in the patent document is limited to a configuration with a power transmitting electrode having one tooth and a power receiving electrode having two teeth, which limits the increase in coupling capacitance. Furthermore, the closer the separation distance is to obtain a larger coupling capacitance, the more abruptly the coupling capacitance changes when the position of the moving object changes due to vibrations or the like.

[0007] The present disclosure discloses a technology for solving the above-mentioned problems, and provides a contactless power supply device with an electrode structure that suppresses a decrease in coupling capacitance while also suppressing fluctuations in coupling capacitance in response to fluctuations in separation distance, thereby enabling an increase in coupling capacitance.

[0008] The contactless power supply device according to the present disclosure includes a fixed body, a movable body movably disposed relative to the fixed body, a power transmitting electrode section disposed parallel to a direction of movement of the movable body, and a power receiving electrode section disposed on the movable body and capacitively coupled to the power transmitting electrode section, wherein the power transmitting electrode section has a plurality of power transmitting electrode teeth, the power receiving electrode section has a plurality of power receiving electrode teeth, a power transmitting electrode connecting section connecting the power transmitting electrode teeth to form a single structure, and a power receiving electrode connecting section connecting the power receiving electrode teeth to form a single structure, the power transmitting electrode teeth and the power receiving electrode teeth face each other at a constant interval, a first capacitance is formed in an opposing region between a first power transmitting electrode tooth of the power transmitting electrode section and a first power receiving electrode tooth of the power receiving electrode section, a second capacitance is formed in a region where a first power transmission electrode tooth of the power transmission electrode portion faces a second power receiving electrode tooth of the power receiving electrode portion; a third capacitance is formed in a region where an end of the first power transmission electrode tooth of the power transmission electrode portion faces a power receiving electrode connecting portion of the power receiving electrode portion; and a fourth capacitance is formed in a region where an end of the second power receiving electrode tooth of the power receiving electrode portion faces a power transmission electrode connecting portion of the power transmission electrode portion, and power is supplied by these contactless power supply devices, wherein a dielectric is provided on at least a part of a surface of the power transmission electrode tooth and the power transmission electrode connecting portion of the power transmission electrode portion, and the power receiving electrode tooth and the power receiving electrode connecting portion of the power receiving electrode portion, which forms the first capacitance, the second capacitance, the third capacitance, and the fourth capacitance.

[0009] According to the contactless power supply device of the present disclosure, a contactless power supply device having an electrode structure is obtained that suppresses a decrease in coupling capacitance, suppresses fluctuations in coupling capacitance in response to fluctuations in separation distance, and enables an increase in coupling capacitance.

[0010] FIG. 1 is a perspective view of a linear conveyance system to which the contactless power supply device according to embodiment 1 is applied. FIG. 2 is a schematic configuration diagram of the contactless power supply device according to embodiment 1. FIG. 3 is a perspective view of the electrode structure of the contactless power supply device according to embodiment 1. FIG. 4 is an explanatory diagram of the basic structure of the electrodes of the contactless power supply device according to embodiment 1. FIG. 5 is an explanatory diagram of the electrode structure of the contactless power supply device according to embodiment 1. FIG. 6 is an explanatory diagram of the electrode structure of the contactless power supply device according to embodiment 2. FIG. 7 is an explanatory diagram of the conditions of the electrode structure of the contactless power supply device according to embodiment 2. FIG. 8 is an explanatory diagram of changes in the capacitance of the electrodes of the contactless power supply device according to embodiment 2. FIG. 9 is an explanatory diagram of the dielectric characteristics of the electrodes of the contactless power supply device according to embodiment 2. FIG. 10 is a summary of changes in capacitance under each condition of the electrodes of the contactless power supply device according to embodiment 2. FIG. 11 is an explanatory diagram of the electrode structure of the contactless power supply device according to embodiment 3.

[0011] Embodiment 1. Embodiment 1 relates to a contactless power transfer device that includes a fixed body, a movable body that is installed so as to be movable relative to the fixed body, a power transmitting electrode unit that is installed parallel to the direction of movement of the movable body, and a power receiving electrode unit that is installed on the movable body and capacitively coupled to the power transmitting electrode unit, wherein the power transmitting electrode unit has a plurality of power transmitting electrode teeth and a power transmitting electrode connection, and the power receiving electrode unit has a plurality of power receiving electrode teeth and a power receiving electrode connection, the power transmitting electrode teeth and the power receiving electrode teeth face each other at a constant interval, a first capacitance and a second capacitance are formed in regions where the power transmitting electrode teeth and the power receiving electrode unit face each other, a third capacitance is formed in a region where an end of the power transmitting electrode tooth and the power receiving electrode connection portion face each other, and a fourth capacitance is formed in a region where the end of the power receiving electrode tooth and the power transmitting electrode connection portion face each other, and a dielectric is provided on surfaces that form the first to fourth capacitances.

[0012] The contactless power supply device according to the first embodiment will be described below with reference to Fig. 1, which is a perspective view of a linear conveyance system to which the contactless power supply device is applied, Fig. 2, which is a schematic configuration diagram of the contactless power supply device, Fig. 3, which is a perspective view of an electrode structure, Fig. 4, which is an explanatory diagram of the basic structure of an electrode, and Fig. 5, which is an explanatory diagram of the electrode structure. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted.

[0013] First, a linear transport system 1000 to which the contactless power supply device 100 of the first embodiment is applied and the configuration of the contactless power supply device will be described with reference to FIGS. 1 and 2. FIG.

[0014] 1 , a linear conveyance system 1000 is composed of a fixed body 1001 and a mobile body (conveyance device) 1002 that runs on an orbit around the fixed body 1001, i.e., is movably installed. The fixed body 1001 has a power transmitting electrode unit 200, and the mobile body 1002 has a power receiving electrode unit 300.

[0015] Next, a specific example of a contactless power supply device 100 applied to a linear transport system 1000 will be described with reference to FIG. 2 . The contactless power supply device 100 comprises a contactless power supply electrode unit 150 composed of a power transmitting electrode unit 200 and a power receiving electrode unit 300, a power transmitting circuit 160, and a power receiving circuit 170. A mobile body 1002 equipped with wheels 1002W moves around a fixed body 1001 in the Y direction, which is the direction from the front to the rear of the page in the figure. The power transmitting electrode unit 200 is fixed to the floor on which the fixed body 1001 is placed by a support base 1001P. A power receiving electrode unit 300 is installed on the mobile body 1002. The power transmitting electrode unit 200 is installed parallel to the direction of movement of the mobile body 1002, and the power receiving electrode unit 300 is arranged to face the power transmitting electrode unit 200.

[0016] The power transmitting electrode unit 200 is connected to the power transmitting circuit 160 via an electric wire 161. The power receiving electrode unit 300 is connected to the power receiving circuit 170 via an electric wire 171. AC power is supplied to the power transmitting electrode unit 200 from the power transmitting circuit 160, and the AC power is transmitted contactlessly to the capacitively coupled power receiving electrode unit 300. The AC power received by the power receiving electrode unit 300 is converted to DC power by the power receiving circuit 170 inside the mobile object 1002 and consumed by a load (not shown) mounted on the mobile object 1002.

[0017] Next, the electrode structure of the contactless power supply device 100 will be described with reference to Figs. 3 to 5. Fig. 3 is a perspective view showing the basic structure of the contactless power supply electrode unit 150 of the contactless power supply device 100. In Fig. 3, the up-down direction in the figure is the Z direction, the left-right direction is the X direction, and the running direction of the mobile object 1002, i.e., the direction in which each power transmitting electrode unit 200 is installed, is the Y direction. The contactless power supply electrode unit 150 is composed of a power transmitting electrode unit 200 and a power receiving electrode unit 300. The contactless power supply electrode unit 150 will be referred to as a power supply electrode unit 150 where appropriate.

[0018] The power transmitting electrode unit 200 has a comb-like structure and is composed of power transmitting electrode teeth 220 extending in the X direction in the figure and power transmitting electrode connectors 230 connecting the teeth in the Z direction in the figure. The power transmitting electrode teeth 220 include a first power transmitting electrode tooth 221, a second power transmitting electrode tooth 222, ..., an m-th power transmitting electrode tooth 22m. The power receiving electrode unit 300 has a comb-like structure and is composed of power receiving electrode teeth 320 extending in the X direction in the figure and a power receiving electrode connector 330 connecting the teeth in the Z direction in the figure. The power receiving electrode teeth 320 include a first power receiving electrode tooth 321, a second power receiving electrode tooth 322, ..., an n-th power receiving electrode tooth 32n. The power transmitting electrode teeth 220 (221, ..., 22m) and the power receiving electrode teeth 320 (321, ..., 32n) are opposed to each other at a fixed distance as shown in Fig. 3. Note that, in terms of the configuration, m and n are integers, and have a relationship of m = n - 1 or m = n + 1. This disclosure is directed to a contactless power supply device 100 having a configuration in which m is 2 or greater in the relationship of m = n - 1.

[0019] 3 , a first dielectric DE1 is provided on each of the opposing surfaces of the first power receiving electrode tooth 321 and the first power transmitting electrode tooth 221. Furthermore, a first dielectric DE1 is provided on each of the opposing surfaces of the first power transmitting electrode tooth 221 and the second power receiving electrode tooth 322. A second dielectric DE2 is provided on each of the opposing surfaces of the tooth end 221T of the first power transmitting electrode tooth 221 and the power receiving electrode connector 330. Furthermore, a second dielectric DE2 is provided on each of the opposing surfaces of the tooth end 322T of the second power receiving electrode tooth 322 and the power transmitting electrode connector 230. By configuring the power feeding electrode 150 of the contactless power feeding device 100 in this manner, it is possible to efficiently ensure an area where the power transmitting electrode tooth 220 and the power receiving electrode tooth 320 face each other.

[0020] Next, the basic structure of the electrodes of the contactless power supply device 100 will be described with reference to Fig. 4. Although the present disclosure is directed to a case where the number of teeth of the power transmitting electrode tooth portion 220 is two or more, for ease of understanding, a case where the number of teeth of the power transmitting electrode tooth portion 220 is one will be described first.

[0021] The power transmitting electrode unit 200 includes a first power transmitting electrode tooth 221, and the power receiving electrode unit 300 includes a first power receiving electrode tooth 321, a second power receiving electrode tooth 322, and a power receiving electrode connecting unit 330. A first dielectric DE1 is provided on each surface where the first power receiving electrode tooth 321 and the first power transmitting electrode tooth 221 face each other, and a first capacitance SC1 is formed in this region. Further, a first dielectric DE1 is provided on each surface where the first power transmitting electrode tooth 221 and the second power receiving electrode tooth 322 face each other, and a second capacitance SC2 is formed in this region. Furthermore, a second dielectric DE2 is provided on each surface where the tooth end 221T of the first power transmitting electrode tooth 221 faces each other and the power receiving electrode connecting unit 330 face each other, and a third capacitance SC3 is formed in this region.

[0022] Next, a case will be described in which the number of teeth of the power transmitting electrode tooth portion 220 of the contactless power supply device 100 in FIG. 5 is two and the number of teeth of the power transmitting electrode tooth portion 220 is three, that is, a case in which one power transmitting electrode tooth portion 220 and one power receiving electrode tooth portion 320 are added to the configuration in FIG. 4 .

[0023] The power transmitting electrode unit 200 includes first power transmitting electrode teeth 221, second power transmitting electrode teeth 222, and a power transmitting electrode connecting unit 230. The power receiving electrode unit 300 includes first power receiving electrode teeth 321, second power receiving electrode teeth 322, third power receiving electrode teeth 323, and a power receiving electrode connecting unit 330. A first dielectric DE1 is provided on each surface where the first power receiving electrode teeth 321 and the first power transmitting electrode teeth 221 face each other, and a first capacitance SC1 is formed in this region. A first dielectric DE1 is also provided on each surface where the first power transmitting electrode teeth 221 and the second power receiving electrode teeth 322 face each other, and a second capacitance SC2 is formed in this region. A first dielectric DE1 is also provided on each surface where the second power receiving electrode teeth 322 and the second power transmitting electrode teeth 222 face each other, and a first capacitance SC1 is formed in this region. Furthermore, a first dielectric DE1 is provided on each of the opposing surfaces of the second power transmitting electrode teeth 222 and the third power receiving electrode teeth 323, and a second capacitance SC2 is formed in this region.

[0024] A second dielectric DE2 is provided on each surface where the tooth end 221T of the first power transmitting electrode tooth 221 faces the power receiving electrode connector 330, and a third capacitance SC3 is formed in this region. Further, a second dielectric DE2 is provided on each surface where the tooth end 322T of the second power receiving electrode tooth 322 faces the power transmitting electrode connector 230, and a fourth capacitance SC4 is formed in this region. Further, a second dielectric DE2 is provided on each surface where the tooth end 222T of the second power transmitting electrode tooth 222 faces the power receiving electrode connector 330, and a third capacitance SC3 is formed in this region.

[0025] 5 , in addition to the first capacitance SC1 and the second capacitance SC2 that are coupled between the teeth of the power transmitting electrode tooth 220 and the power receiving electrode tooth 320, and the third capacitance SC3 that is coupled between the power transmitting electrode tooth 220 and the power receiving electrode connection portion 330, a fourth capacitance SC4 that is coupled between the power receiving electrode tooth 320 and the power transmitting electrode connection portion 230 is formed. As a result, it is possible to increase the ratio of the coupling capacitances (third capacitance SC3 and fourth capacitance SC4) between the power transmitting electrode tooth and the power receiving electrode connection portion, and between the power receiving electrode tooth and the power transmitting electrode connection portion, to the overall coupling capacitance.

[0026] In the above description, it is assumed that the first dielectric DE1 is provided over the entire surfaces of the opposing surfaces of the power transmitting electrode teeth 220 and the power receiving electrode teeth 320, and the second dielectric DE2 is provided over the entire surfaces of the opposing surfaces of the power transmitting electrode teeth 220 and the power receiving electrode connecting portion 330 and the opposing surfaces of the power receiving electrode teeth 320 and the power transmitting electrode connecting portion 230. However, the same effect can be achieved even if the first dielectric DE1 and the second dielectric DE2 are provided over only part of the opposing surfaces rather than over the entire surfaces.

[0027] Here, the features and effects of the contactless power supply device of the first embodiment are summarized. The power transmitting electrode and power receiving electrode of the contactless power supply device for contactless power supply using an electric field coupling system have a comb-like structure. By utilizing the characteristics of four types of coupling capacitance (first to fourth capacitances) formed between the power transmitting electrode and the power receiving electrode, a decrease in coupling capacitance is suppressed, resulting in high stability against vibrations of the moving object. Specifically, a dielectric is provided on the surface forming the opposing area between the power transmitting electrode teeth and the power receiving electrode teeth. Furthermore, a dielectric is provided on the surface forming the opposing area between the power transmitting electrode teeth and the power receiving electrode connector and the surface forming the opposing area between the power receiving electrode teeth and the power transmitting electrode connector. As a result, the dielectric functions as an insulator, thereby increasing the breakdown voltage and reducing the separation distance, thereby increasing the coupling capacitance.

[0028] As described above, the contactless power supply device of the first embodiment can suppress fluctuations in coupling capacitance with fluctuations in separation distance, and can realize a contactless power supply device with an electrode structure that allows for an increase in coupling capacitance.

[0029] Second Embodiment In a second embodiment, the coupling capacitance is optimized by adjusting the parameters of the electrode structure of the contactless power supply device.

[0030] The contactless power supply device of embodiment 2 will be described, focusing on the differences from embodiment 1, with reference to Fig. 6 which is an explanatory diagram of the electrode structure of the contactless power supply device, Fig. 7 which is an explanatory diagram of the conditions of the electrode structure, Figs. 8 and 9 which are explanatory diagrams of changes in the capacitance of the electrodes, Fig. 10 which is an explanatory diagram of the characteristics of the dielectric of the electrodes, and Fig. 11 which is a summary of changes in capacitance under each condition of the electrodes. In the configuration diagram of embodiment 2, parts which are the same as or equivalent to those of embodiment 1 are given the same reference numerals.

[0031] FIG. 6 defines the parameters (thickness, separation distance, facing area, and offset amount) of the dielectric that are prerequisites for optimizing the coupling capacitance by adjusting the parameters of the electrode structure of the contactless power transfer device. In FIG. 6, the thickness of the first dielectric DE1 is dDE1, and the thickness of the second dielectric DE2 is dDE2. The relative dielectric constant of the first dielectric DE1 is εs1, and the relative dielectric constant of the second dielectric DE2 is εs2. The regions forming the first capacitance SC1 and the second capacitance SC2 have a separation distance d1 and a facing area S1. The regions forming the third capacitance SC3 and the fourth capacitance SC4 have a separation distance d2 and a facing area S2. The positional fluctuation caused by the vibration of the mobile body 1002 traveling on an orbit around the fixed body 1001 is represented by a, with the vertical (Z-direction) component in FIG. 6 being dominant over the horizontal (Y-direction) component.

[0032] If the total coupling capacitance of the contactless power supply electrode section 150 is C0, the coupling capacitance of the first capacitance SC1 is C1, the coupling capacitance of the second capacitance SC2 is C2, and the coupling capacitance of the third capacitance SC3 and the fourth capacitance SC4 is C3, the respective capacitances are expressed by the following formulas (1) to (4). Note that the unit of each formula is [F]. Note that this disclosure is directed to a contactless power supply device 100 having a configuration in which m is 2 or greater in the relationship m=n-1.

[0033] C0=C1+C2+C3...(1) C1=(ε0εs1S1) / (2dDE1+εs1(d1-a))×m...(2) C2=(ε0εs1S1) / (2dDE1+εs1(d1+a))×m...(3) C3=(ε0εs2S2) / (2dDE2+εs2d2)×(2m-1)...(4)

[0034] As can be seen from equations (1) to (4), the first capacitance SC1 and the second capacitance SC2 change depending on the deviation a of the separation distance due to vibration, but the third capacitance SC3 and the fourth capacitance SC4 do not change depending on a.

[0035] FIG. 7 shows the conditions for each parameter of the electrode structure. Six conditions, Condition 1 through Condition 6, were set. The opposing areas S1 and S2 were set based on the assumption that S1 > S2, generally, in order to efficiently obtain coupling capacitance. FIG. 8 shows the percentage of the third capacitance SC3 and the fourth capacitance SC4 (C3) in the total coupling capacitance (C0) corresponding to these six conditions. FIG. 9 shows the total coupling capacitance (C0) corresponding to these six conditions. In FIGS. 8 and 9, Condition 1 is represented by a thin solid line, Condition 2 by a thin dashed-dot line, Condition 3 by a thin dashed-dot line, Condition 4 by a thick solid line, Condition 5 by a thick dashed-dot line, and Condition 6 by a thick dashed-dot line. In FIGS. 8 and 9, the curves for Condition 2 and Condition 3 overlap, so Condition 3 is drawn using a thin dashed-dot line. The curves for Condition 5 and Condition 6 also overlap, so Condition 6 is drawn using a thick dashed-dot line.

[0036] Next, the changes in each parameter and their characteristics for each condition in FIG. 7 are described with reference to FIGS. 8 and 9. Note that "dielectric thickness" will be referred to as "dielectric thickness" where appropriate. [Condition 1] As shown in FIG. 7, the number of teeth m of the power transmitting electrode is 1, the facing area S1 is 1000 mm2, S2 is 300 mm2, and the separation distances d1 and d2 are 6 mm. Note that no dielectric is inserted. As shown in FIG. 8, the ratio of C3 to C0 at a = 0 mm is 13.0%. As shown in FIG. 9, C0 at a = 0 mm is 3.4 pF, and the rate of change in C0 when a = 0 mm is shifted to 3 mm is +29.0%.

[0037] [Condition 2] As shown in Figure 7, in Condition 2, the number of teeth m of the power transmitting electrode in Condition 1 is changed from 1 to 2. No dielectric is inserted. As shown in Figure 8, the proportion of C3 to C0 when a = 0 mm is 18.4%, and as shown in Figure 9, C0 when a = 0 mm is 7.2 pF, and the rate of change in C0 when a = 3 mm is shifted from 0 is +27.2%. These results show that by increasing m to 2 or more compared to Condition 1, an increase in coupling capacitance and a reduction in the rate of change in C0 depending on the value of a are achieved.

[0038] [Condition 3] As shown in Figure 7, in Condition 3, the separation distances d1 and d2 of Condition 2 are changed from 6 mm to 4.5 mm, and a first dielectric DE1 and a second dielectric DE2 are inserted. The relative dielectric constants εs1 and εs2 are set to 2.67, and the dielectric thicknesses dDE1 and dDE2 are set to 2 mm. As shown in Figure 8, the ratio of C3 to C0 at a = 0 mm is 18.4%. As shown in Figure 9, C0 at a = 0 mm is 7.2 pF, and the rate of change in C0 when a = 0 mm is shifted to 3 mm is +27.2%. This result is similar to that of Condition 2, indicating that the insertion of a dielectric can shorten the separation distance.

[0039] [Condition 4] As shown in Fig. 7, condition 4 is achieved by changing the relative dielectric constant of the first dielectric DE1 in condition 3 from 2.67 to 2, and the relative dielectric constant of the second dielectric DE2 from 2.67 to 100. As shown in Fig. 8, the proportion of C3 to C0 at a = 0 mm is 24.4%, and as shown in Fig. 9, C0 at a = 0 mm is 7.2 pF, and the rate of change in C0 when a is shifted from 0 to 3 mm is +20.5%. This result shows that, compared to condition 3, the same coupling capacitance is maintained, and a reduction in the rate of change in C0 due to the value of a is achieved.

[0040] [Condition 5] As shown in Figure 7, condition 5 is achieved by changing the separation distances d1 and d2 of condition 4 from 4.5 mm to 3.2 mm and changing the dielectric thickness of the first dielectric from 2 mm to 3.3 mm. As shown in Figure 8, the ratio of C3 to C0 when a = 0 mm is 31.1%, and as shown in Figure 9, C0 when a = 0 mm is 7.9 pF, and the rate of change of C0 when a = 3 mm is shifted from 0 pF to 3 mm is +18.7%. This result shows that, compared to condition 4, by shortening the separation distances d1 and d2 while increasing the dielectric thickness dDE1 of the first dielectric DE1, it is possible to further increase the ratio of C3 to C0 when a = 0 mm.

[0041] [Condition 6] As shown in Figure 7, Condition 6 is the same as Condition 5, except that the dielectric thickness of the first dielectric is returned to 2 mm from 3.3 mm and the separation distance d1 is changed from 3.3 mm to 4.5 mm. As shown in Figure 8, the ratio of C3 to C0 at a = 0 mm is 31.1%. As shown in Figure 9, C0 at a = 0 mm is 7.9 pF, and the rate of change in C0 when a = 0 mm is shifted to 3 mm is +18.7%. This result indicates that, compared to Condition 4, by keeping both dielectric thicknesses dDE1 and dDE2 the same (2 mm) and reducing the separation distance d2 from 4.5 mm to 3.3 mm, it is possible to further increase the ratio of C3 to C0 at a = 0 mm. Furthermore, Condition 6 is a different aspect of Condition 5, since C0 and the ratio of C3 to C0 are the same as those in Condition 5.

[0042] The dielectric constant values ​​of 2 and 2.67 were adopted for the first dielectric DE1. These dielectric constant values ​​assume the use of polypropylene or polyethylene terephthalate, which are polypropylene-based materials. The dielectric constant value of 100 was adopted for the second dielectric DE2. This dielectric constant value assumes the use of titanium oxide or barium titanate, which are barium titanate-based materials. For reference, Figure 10 shows representative dielectrics and their dielectric constants. This list is taken from (https: / / www.aictech-inc.com / information / capacitor_foundation03.html). In Figure 10, "A" indicates candidates for the first dielectric, and "B" indicates candidates for the second dielectric.

[0043] The results of the investigation of conditions 1 to 6 described above are summarized in FIG. 11 . Conditions 1 and 2 are cases where no dielectrics are used. Condition 3 is a case where dielectrics with the same dielectric constant are inserted into the surfaces forming C1 to C3. Conditions 4 to 6 are cases where dielectrics with different dielectric constants are inserted into the surfaces forming C1 and C2 and the surface forming C3. FIG. 11 shows that by setting the number m of power transmitting electrode teeth 220 of the power transmitting electrode 200 to 2 or more and inserting dielectrics with different dielectric constants, it is possible to suppress a decrease in coupling capacitance and realize an electrode structure that is highly stable against vibrations of the moving body 1002.

[0044] The following describes the configuration and features of a contactless power supply electrode that embodies the above-mentioned study results. When the dielectric provided on the surface forming the first capacitance SC1 and the second capacitance SC2 is the first dielectric DE1, and the dielectric provided on the surface forming the third capacitance SC3 and the fourth capacitance SC4 is the second dielectric DE2, it is effective to use a dielectric material whose relative dielectric constant is higher than that of the first dielectric DE1. This configuration reduces the rate of variation of the overall coupling capacitance (C0) and makes it possible to increase the proportion of the third capacitance SC3 and the fourth capacitance SC4 (C3) in the overall coupling capacitance (C0).

[0045] In the case where the first dielectric DE1 has a dielectric constant of 2 and the second dielectric DE2 has a dielectric constant of 100, the standard value of the separation distance between the surfaces forming the first capacitance SC1 and the second capacitance SC2 is 4.5 mm, the standard value of the separation distance between the surfaces forming the third capacitance SC3 and the fourth capacitance SC4 is 4.5 mm, the standard value of the thickness of the first dielectric DE1 is 2 mm, and the standard value of the thickness of the second dielectric DE2 is 2 mm, it is effective to set the separation distance between the surfaces forming the first capacitance SC1 and the second capacitance SC2 and the separation distance between the surfaces forming the third capacitance SC3 and the fourth capacitance SC4 to the same value of 3.2 mm, which is smaller than the standard value of 4.5 mm, and to set the thickness of the first dielectric DE1 to a value of 3.3 mm, which is larger than the standard value of 2 mm. This configuration reduces the rate of variation of the overall coupling capacitance (C0) and makes it possible to increase the proportion of the third capacitance SC3 and the fourth capacitance SC4 (C3) to the overall coupling capacitance (C0).

[0046] Furthermore, when the first dielectric DE1 has a dielectric constant of 2 and the second dielectric DE2 has a dielectric constant of 100, the standard value of the separation distance between the surfaces forming the first capacitance SC1 and the second capacitance SC2 is 4.5 mm, the standard value of the separation distance between the surfaces forming the third capacitance SC3 and the fourth capacitance SC4 is 4.5 mm, the standard value of the thickness of the first dielectric DE1 is 2 mm, and the standard value of the thickness of the second dielectric DE2 is 2 mm, it is also effective to set the separation distance between the surfaces forming the third capacitance SC3 and the fourth capacitance SC4 to 3.2 mm, which is smaller than the standard value of 4.5 mm. By adopting this configuration, it is possible to reduce the rate of variation of the overall coupling capacitance (C0) and increase the proportion of the third capacitance SC3 and the fourth capacitance SC4 (C3) to the overall coupling capacitance (C0).

[0047] As described above, the contactless power supply device of the second embodiment can suppress a decrease in coupling capacitance while suppressing fluctuations in coupling capacitance in response to fluctuations in separation distance, thereby realizing a contactless power supply device with an electrode structure that can increase coupling capacitance. Furthermore, by selecting appropriate parameters, the coupling capacitance can be optimized.

[0048] Third Embodiment In a third embodiment, the non-contact power supply electrode portion is made lighter and smaller.

[0049] The contactless power supply device of embodiment 3 will be described with reference to FIG. 12 , which is an explanatory diagram of the electrode structure, focusing on the differences from embodiment 1. In the configuration diagram of embodiment 3, parts that are the same as or equivalent to those of embodiment 1 are given the same reference numerals. Note that in embodiment 3, for example, the letter "A" is added to the names of the contactless power supply device 100A, the power transmitting electrode unit 200A, and the power receiving electrode unit 300A to distinguish them from embodiment 1.

[0050] Figure 12 shows the main parts of Figure 5, and the configuration is the same as that explained below. Note that if the dimensions of each part change, the capacity of that area will also change, so they are not strictly the same, but for the sake of clarity, only the components are distinguished.

[0051] The power transmitting electrode unit 200A includes a first power transmitting electrode tooth 221A and a power transmitting electrode connecting unit 230A. The power receiving electrode unit 300A includes a first power receiving electrode tooth 321A, a second power receiving electrode tooth 322A, and a power receiving electrode connecting unit 330A. A first dielectric DE1 is provided on each of the opposing surfaces of the first power receiving electrode tooth 321A and the first power transmitting electrode tooth 221A, and a first capacitance SC1 is formed in this region. Furthermore, a first dielectric DE1 is provided on each of the opposing surfaces of the first power transmitting electrode tooth 221A and the second power receiving electrode tooth 322A, and a second capacitance SC2 is formed in this region.

[0052] A second dielectric DE2 is provided on each of the opposing surfaces of the tooth end portion 221AT of the first power transmitting electrode tooth portion 221A and the power receiving electrode connecting portion 330A, and a third capacitance SC3 is formed in this region. Also, a second dielectric DE2 is provided on each of the opposing surfaces of the tooth end portion 322AT of the second power receiving electrode tooth portion 322A and the power transmitting electrode connecting portion 230A, and a fourth capacitance SC4 is formed in this region.

[0053] The features of the non-contact power feeding electrode 150A of the third embodiment will be described. The opposing area S2 of the regions forming the third capacitance SC3 and the fourth capacitance SC4 and the separation distance d2 are the same as those in FIG. 5 . The Z-direction thickness of the tooth end 221AT of the first power transmitting electrode tooth 221A is the same as that in FIG. 5 , but the Z-direction thickness between the power transmitting electrode connecting portion 230A and this end is reduced. The Z-direction thickness of the tooth end 322AT of the second power receiving electrode tooth 322A is the same as that in FIG. 5 , but the Z-direction thickness between the power receiving electrode connecting portion 330A and this end is reduced. Furthermore, the Z-direction thickness of the first power receiving electrode tooth 321A is reduced. That is, the power transmitting electrode tooth 220A and the power receiving electrode tooth 320A are thinned except for their tooth ends. The X-direction length of the tooth end 221AT of the first power transmitting electrode tooth 221A and the X-direction length of the tooth end 322AT of the second power receiving electrode tooth 322A may be any dimension that can reliably fix the second dielectric DE2.

[0054] With this structure, there is no need to increase the thickness of the tooth portion in order to increase the third capacitance SC3 and the fourth capacitance SC4, and the non-contact power supply electrode portion 150A can be made lighter and smaller, and costs can be reduced.

[0055] As described above, the contactless power supply device of the third embodiment can suppress a decrease in coupling capacitance while suppressing fluctuations in coupling capacitance in response to fluctuations in separation distance, thereby realizing a contactless power supply device with an electrode structure that can increase coupling capacitance. Furthermore, it is possible to reduce the weight, size, and cost of the contactless power supply device.

[0056] Although various exemplary embodiments and examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are anticipated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0057] REFERENCE SIGNS LIST 100 Non-contact power supply device, 150 Non-contact power supply electrode section, 160 Power transmission circuit, 161 Wire, 170 Power reception circuit, 171 Wire, 200 Power transmission electrode section, 220 Power transmission electrode tooth section, 230 Power transmission electrode connection section, 221 First power transmission electrode tooth section, 222 Second power transmission electrode tooth section, 300 Power reception electrode section, 320 Power reception electrode tooth section, 321 First power reception electrode tooth section, 322 Second power reception electrode tooth section, 323 Third power reception electrode tooth section, 330 Power reception electrode connection section, 1000 Linear transport system, 1001 Fixed body, 1002 Moving body, 1001P Support base, 1002W Wheel, DE1 First dielectric, DE2 Second dielectric, SC1 First capacitance, SC2 Second capacitance, SC3 Third capacitance, SC4 Fourth capacitance, d1 separation distance, d2 separation distance, dDE1 thickness of first dielectric, dDE2 thickness of second dielectric, S1 opposing area, S2 opposing area, 100A contactless power supply device, 150A contactless power supply electrode portion, 200A power transmission electrode portion, 221A first power transmission electrode tooth portion, 230A power transmission electrode connection portion, 300A power receiving electrode portion, 321A first power receiving electrode tooth portion, 322A second power receiving electrode tooth portion, 330A power receiving electrode connection portion.

Claims

1. A power transmission device comprising: a fixed body; a movable body movably installed relative to the fixed body; a power transmission electrode installed parallel to the direction of movement of the movable body; and a power receiving electrode installed on the movable body and capacitively coupled to the power transmission electrode, wherein the power transmission electrode has a plurality of power transmission electrode teeth, the power receiving electrode has a plurality of power receiving electrode teeth, a power transmission electrode connecting section connecting the power transmission electrode teeth to form a single structure, and a power receiving electrode connecting section connecting the power receiving electrode teeth to form a single structure, the power transmission electrode teeth and the power receiving electrode teeth face each other at a constant distance, a first capacitance is formed in an opposing region between a first power transmission electrode tooth of the power transmission electrode and a first power receiving electrode tooth of the power receiving electrode, and a second capacitance is formed in an opposing region between a first power transmission electrode tooth of the power transmission electrode and a second power receiving electrode tooth of the power receiving electrode, a third capacitance is formed in an opposing region between an end of a first power transmission electrode tooth portion of the power transmission electrode portion and a power reception electrode connecting portion of the power reception electrode portion, and a fourth capacitance is formed in an opposing region between an end of a second power reception electrode tooth portion of the power reception electrode portion and the power transmission electrode connecting portion of the power transmission electrode portion, and power is supplied from the third capacitance and the fourth capacitance, wherein a dielectric is provided on at least a part of a surface of the power transmission electrode tooth portion and the power transmission electrode connecting portion of the power transmission electrode portion, and the power reception electrode tooth portion and the power reception electrode connecting portion of the power reception electrode portion, which forms the first capacitance, the second capacitance, the third capacitance, and the fourth capacitance.

2. A contactless power supply device as described in claim 1, wherein the dielectric is provided on at least a portion of the surface forming the first capacitance, at least a portion of the surface forming the second capacitance, at least a portion of the surface forming the third capacitance, and at least a portion of the surface forming the fourth capacitance.

3. A contactless power supply device according to claim 1 or 2, wherein when a dielectric provided on either or both of the surfaces forming the first capacitance and the second capacitance is defined as a first dielectric, and a dielectric provided on either or both of the surfaces forming the third capacitance and the fourth capacitance is defined as a second dielectric, the second dielectric is a dielectric made of a material having a higher dielectric constant than the first dielectric.

4. The contactless power supply device according to claim 3, wherein, when a standard value of the separation distance between the surfaces forming the first capacitance, the second capacitance, the third capacitance, and the fourth capacitance is a first standard value, and a standard value of the thickness of the first dielectric and the second dielectric is a second standard value, the separation distance between the surfaces forming the first capacitance, the second capacitance, the third capacitance, and the fourth capacitance is a value smaller than the first standard value, and the thickness of the first dielectric is a value larger than the second standard value.

5. The contactless power supply device according to claim 3, wherein, when a standard value of the separation distance between the surfaces forming the first capacitance, the second capacitance, the third capacitance, and the fourth capacitance is defined as a first standard value, and a standard value of the thickness of the first dielectric and the thickness of the second dielectric is defined as a second standard value, the separation distance between the surfaces forming the third capacitance and the fourth capacitance is a value smaller than the first standard value.

6. A contactless power supply device according to any one of claims 3 to 5, wherein the first dielectric is a propylene-based material and the second dielectric is a barium titanate-based material.

7. The contactless power supply device according to any one of claims 1 to 6, wherein, when the direction in which the power transmitting electrode tooth and the power receiving electrode tooth face each other is defined as the facing direction, the power transmitting electrode tooth that faces the power receiving electrode connection portion has a thickness in the facing direction from the power transmitting electrode connection portion to an end of the power transmitting electrode tooth that is smaller than the thickness of the end of the power transmitting electrode tooth, the power receiving electrode tooth that faces the power transmitting electrode connection portion has a thickness in the facing direction from the power receiving electrode connection portion to the end of the power receiving electrode tooth that is smaller than the thickness of the end of the power receiving electrode tooth, and the power receiving electrode tooth that does not face the power transmitting electrode connection portion has a thickness in the facing direction of the power receiving electrode tooth that is the same as the thickness of the power receiving electrode tooth that faces the power transmitting electrode connection portion.

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