JP7550806B2 - Coil for non-contact power supply and variable diameter coil for non-contact power supply - Google Patents

Description

The present invention relates to a coil for contactless power supply, and in particular to a coil having a spiral shape.

There has been extensive research and development into contactless power transfer devices. A contactless power transfer device (power transmission device) supplies power to a power receiving device without being wired to the power receiving device. Some contactless power transfer devices use a magnetic resonance method, which supplies power to a power receiving device by resonance of a resonant circuit. The contactless power transfer device includes a power transmission coil, and the power receiving device includes a power receiving coil. In this method, power is supplied from the contactless power transfer device to the power receiving device by resonance between a resonant circuit formed on the power transmission coil side and a resonant circuit formed on the power receiving coil side.

Power receiving devices include devices that are placed at a distance from the contactless power supply device, such as mobile information terminals and electric vehicles. Generally, these devices are equipped with a battery (secondary battery) that can be repeatedly charged and discharged, and the battery is charged by the contactless power supply device. When charging, the power receiving device is placed at a specified position on the contactless power supply device, and charging power is supplied from the contactless power supply device to the battery of the power receiving device.

The following Patent Document 1 describes a contactless power supply device using a magnetic resonance method. Also, as described in Patent Document 2, a technology has been devised for adjusting the capacitance of a variable capacitor in a resonant circuit provided in a contactless power supply device to prevent a decrease in the power transmitted to a power receiving device such as a portable information terminal. Patent Document 2 further describes a technology for supplying power from a contactless power supply device to a power receiving device using a relay resonator.

Patent document 3 describes a device that has multiple series LC circuits and performs contactless power supply by selecting one of the multiple series LC circuits or by selecting multiple circuits and connecting them in series.

JP 2018-110471 A JP 2015-164398 A JP 2017-5772 A

In a non-contact power supply device, the power supplied to the power receiving device may differ depending on the positional relationship between the non-contact power supply device and the power receiving device, such as the distance between the non-contact power supply device and the power receiving device, and the direction or posture of the power receiving device as viewed from the non-contact power supply device. For example, in a non-contact power supply device using a magnetic resonance method, the resonance frequency may change depending on the positional relationship between the non-contact power supply device and the power receiving device, which may result in a change in the power supplied to the power receiving device. In addition to changes in the resonance frequency, the power supplied to the power receiving device may differ depending on the size of the power transmitting coil and the power receiving coil. Depending on the positional relationship between the non-contact power supply device and the power receiving device, and the size of the power transmitting coil or the power receiving coil, the power transmission efficiency may decrease.

The present invention aims to improve the efficiency of power transmission from a non-contact power supply device to a power receiving device.

The present invention is characterized by comprising a conductor that forms a spiral shape by shifting outward by one pitch for each revolution, a first contact that contacts the conductor at a first position on the conductor and connects the conductor to a first terminal, a second contact that contacts the conductor at a position N revolutions outside the first position and connects the conductor to a second terminal, and a rotation drive mechanism that moves the first contact and the second contact in the circumferential direction.

The present invention is characterized by comprising a conductor that forms a spiral shape so as to shift outward by one pitch for each revolution, a first contact that contacts the conductor at any first position on the conductor and connects the conductor to a first terminal, a second contact that contacts the conductor at a position N revolutions outward from the first position and connects the conductor to a second terminal, and a radial drive mechanism that moves the first contact and the second contact in the radial direction of the conductor. Preferably, the device comprises a substrate, and the conductor is formed in a groove formed in a flat surface of the substrate.

The present invention is also characterized in that it comprises a conductor that forms a spiral shape so as to shift outward by one pitch with each revolution, and a plurality of switches that are provided at each predetermined revolution of the conductor, the conductor having gaps that form a pair of cut ends at the positions where each of the switches is provided, an inner switch that is one of the plurality of switches connects one of the pair of cut ends that faces outward to a first terminal, and an outer switch among the plurality of switches that is a certain number of revolutions outward from the inner switch connects the other cut end that faces inward to a second terminal, the inner switch and the outer switch are selected from the plurality of switches, and a coil diameter of an effective coil between the first terminal and the second terminal is variable .

Preferably, when another switch is present in the section of the conducting wire between the inner switch and the outer switch, the other switch is in a state in which the pair of cut ends are connected.

Preferably, the device includes a substrate, and the conductive wire is formed in a groove formed in a flat surface of the substrate.

The present invention can improve the efficiency of power transmission from a non-contact power supply device to a power receiving device.

FIG. 1 is a diagram illustrating a configuration of a contactless power supply system. FIG. 2 is a diagram showing a variable-diameter coil according to the first embodiment. 5A and 5B are diagrams illustrating a contact portion according to a first configuration example. 13A and 13B are diagrams illustrating a contact portion according to a second configuration example. FIG. 11 is a diagram showing a variable-diameter coil according to a second embodiment. FIG. 13 is a diagram showing a schematic configuration of three loop selection switches provided for a section of a spiral conductor that makes two turns. FIG. 13 is a diagram showing the relationship between radius and inductance.

An embodiment of the present invention will be described with reference to each figure. Identical components shown in multiple figures are given the same reference numerals to simplify the description. Terms such as up, down, left, and right in this specification indicate directions in the figures. These directional terms do not limit the orientation of each component when it is placed.

Figure 1 shows the configuration of a contactless power supply system 100 according to an embodiment of the present invention. The contactless power supply system 100 includes a power transmission device (contactless power supply device) 1 and a power receiving device 2. Power is supplied contactlessly from the power transmission device 1 to the power receiving device 2, and the power receiving device 2 supplies power to a load circuit 36. Supply power information indicating the power that the power receiving device 2 acquires from the power transmission device 1 and supplies to the load circuit 36 is wirelessly transmitted from the power receiving device 2 to the power transmission device 1. The power transmission device 1 controls the state of the power transmission device 1 based on the supply power information, and adjusts the power supplied from the power transmission device 1 to the power receiving device 2.

The operation of the contactless power supply system 100 will be specifically described. The power transmission device 1 includes a power supply circuit 10, a matching circuit 12, a variable diameter coil 14, a power transmission side radio unit 16, and a control unit 18. The power supply circuit 10 supplies power to the variable diameter coil 14 via the matching circuit 12 according to the control of the control unit 18. The matching circuit 12 adjusts the impedance matching state between the power supply circuit 10 and the variable diameter coil 14 according to the control of the control unit 18. The variable diameter coil 14, together with a capacitive element included in the matching circuit 12, constitutes a power transmission side resonant circuit (power transmission side resonant circuit).

The power receiving device 2 includes a power receiving coil 30, a power receiving circuit 32, and a power receiving side radio unit 34. The power receiving coil 30, together with a capacitive element included in the power receiving circuit 32, constitutes a power receiving side resonant circuit (power receiving side resonant circuit).

The variable diameter coil 14 and the power receiving coil 30 are coupled by a magnetic field or electromagnetic waves. When the variable diameter coil 14 and the power receiving coil 30 are coupled, the power transmitting resonant circuit and the power receiving resonant circuit resonate, and power is supplied contactlessly from the power transmitting resonant circuit to the power receiving resonant circuit. The power receiving circuit 32 obtains power from the power receiving coil 30 and outputs it to the load circuit 36.

The power receiving circuit 32 measures the power supplied to the load circuit 36 and outputs a supply power value indicating the power supplied to the load circuit 36 to the power receiving side wireless unit 34. The power receiving side wireless unit 34 wirelessly transmits supply power information including the supply power value to the power transmitting side wireless unit 16. The power transmitting side wireless unit 16 receives the supply power information and outputs it to the control unit 18.

The control unit 18 adjusts the state of the matching circuit 12 and the variable diameter coil 14 based on the supply power value included in the supply power information. The control unit 18 adjusts the state of the matching circuit 12 and the variable diameter coil 14, for example, so that the supply power value exceeds a predetermined power threshold. The matching circuit 12 may include a variable constant element such as a variable capacitor or a variable inductor. The control unit 18 may adjust the constant of the variable constant element based on the supply power value.

As described below, the variable diameter coil 14 has a variable radius (coil diameter) around a flat surface. The control unit 18 may adjust the coil diameter, for example, so that the supplied power value exceeds a power threshold.

Figure 2 shows a variable diameter coil 14-1 according to the first embodiment. The variable diameter coil 14-1 includes a substrate 40, a spiral conductor 42, and a contact portion 44. A groove 43 is formed on the substrate 40, which forms a spiral shape so as to shift outward by one pitch for each turn. The spiral conductor 42 is formed on the surface of the groove 43, and forms a spiral shape so as to shift outward by one pitch for each turn, just like the groove 43. An inner conductor 48 is formed on the inner end of the spiral conductor 42, and an outer conductor 50 is formed on the outside of the spiral conductor 42. The inner conductor 48 may be formed on the surface of a central recess 49 that is connected to the inner end of the groove 43. The central recess 49 may be a region that is recessed in a substantially circular shape at the center of the spiral shape formed by the groove 43. The outer conductor 50 may be formed on the surface of an outer groove 51 that is connected to the outer end of the groove 43. The outer groove 51 may make one turn around the outside of the groove 43.

In FIG. 3, as a first configuration example of the contact portion 44, the contact portion 44A is shown together with the substrate 40, the groove 43, and the spiral conductor 42. The contact portion 44A includes a guide rod 52, a first terminal 58, a first conductor 60, a second terminal 62, a second conductor 64, and a movable portion 66. The movable portion 66 includes a movable portion housing 67, a first contact 54, and a second contact 56. The first contact 54 and the second contact 56 are formed by conductors that protrude downward from the movable portion housing 67. The first contact 54 and the second contact 56 are fixed to the movable portion housing 67 at a fixed interval in the radial direction of the spiral conductor 42.

The first contact 54 contacts the spiral conductor 42 at a first position on the spiral conductor 42. The first contact 54 is connected to a first terminal 58 via a first conductor 60, and connects the spiral conductor 42 to the first terminal 58. The second contact 56 contacts the spiral conductor 42 at a second position that is N turns outside the first position. The second contact 56 is connected to a second terminal 62 via a second conductor 64, and connects the spiral conductor 42 to the second terminal 62.

In the example shown in FIG. 3, N=2, and the distance between the first contact 54 and the second contact 56 is two pitches of the spiral conductor 42.

One end of the guide rod 52 is connected to a rotation drive mechanism 68 provided at the center of the spiral shape of the groove 43. The guide rod 52 extends from the rotation drive mechanism 68 toward the radial outside of the spiral shape of the groove 43 (positive direction of the r axis). The guide rod 52 is rotatable in the circumferential direction (azimuth angle θ direction) along the surface of the substrate 40, with the connection part with the rotation drive mechanism 68 as the center and its longitudinal direction as the radial direction.

The first conducting wire 60 and the second conducting wire 64 are provided inside the guide rod 52 and extend along its longitudinal direction. One radially inner end of the first conducting wire 60 is connected to the first terminal 58, and one radially inner end of the second conducting wire 64 is connected to the second terminal 62. The other ends of the first conducting wire 60 and the second conducting wire 64 may be open.

The movable part 66 may include a radial drive mechanism 74 that moves the movable part housing 67 along the guide rod 52. The conductor connected to the first contact 54 is in slidable contact with the first conductor 60 inside the guide rod 52. The conductor connected to the second contact 56 is in slidable contact with the second conductor 64 inside the guide rod 52. As the guide rod 52 moves in the circumferential direction, the movable part 66 moves in the radial direction so that the first contact 54 and the second contact 56 come into contact with two positions on the spiral conductor 42 that are spaced apart by N pitches. The first contact 54 and the second contact 56 slide radially while in contact with the spiral conductor 42 between two positions on the spiral conductor 42 that are spaced apart by N pitches.

In addition, if the rotation drive mechanism 68 applies a circumferential moving force to the first contact 54 and the second contact 56, which in turn applies a radial moving force to the first contact 54 and the second contact 56 from the groove 43, thereby moving the first contact 54 and the second contact 56 radially, then the radial drive mechanism 74 does not need to be provided.

In the example shown in FIG. 3, as the guide rod 52 moves in the circumferential direction, the movable part 66 moves in the radial direction so that the first contact 54 and the second contact 56 come into contact with two positions that are two pitches apart on the spiral conductor 42. The first contact 54 and the second contact 56 slide in the radial direction while in contact with the spiral conductor 42 at two positions that are two pitches apart on the spiral conductor 42.

The first contact 54 and the second contact 56 slide in the circumferential direction while maintaining electrical connection with the first conductor 60 and the second conductor 64, respectively, while the movable part 66 having the first contact 54 and the second contact 56 moves in the radial direction. As a result, a current path is formed from the first terminal 58 through the first conductor 60 to the first contact 54, and to one of two positions (first position) that are N pitches apart on the spiral conductor 42. Furthermore, a current path is formed from the first position to the other position (second position) that is N turns around the spiral conductor 42 toward the outside. Furthermore, a current path is formed from the second contact 56 that contacts the second position to the second terminal 62 through the second conductor 64.

That is, a section of the spiral conductor 42 extending from the first position to the second position, which is N turns around the spiral conductor 42 toward the outside, is connected between the first terminal 58 and the second terminal 62. In the example shown in FIG. 3, a section of the spiral conductor 42 that has made two turns is connected between the first terminal 58 and the second terminal 62.

The movable part 66 moves in the radial direction, changing the section of the spiral conductor 42 through which current flows, i.e., the diameter of the effective coil in which the spiral conductor 42 effectively operates as a coil. The control unit 18 (Fig. 1) controls the rotation drive mechanism 68 to move the guide rod 52 in the circumferential direction, and controls the radial drive mechanism 74 to move the movable part 66 in the radial direction. Furthermore, if the radial drive mechanism 74 is not provided, the control unit 18 (Fig. 1) controls the rotation drive mechanism 68 to move the guide rod 52 in the circumferential direction. This adjusts the diameter of the effective coil connected between the first terminal 58 and the second terminal 62.

In the above, an embodiment has been shown in which the first contact 54 and the second contact 56 slide along the spiral conductor 42 by moving the movable part 66 in the circumferential direction of the spiral conductor 42 while moving in the radial direction of the spiral conductor 42. In this way, a configuration in which the first contact 54 and the second contact 56 do not slide along the spiral conductor 42, but the first contact 54 and the second contact 56 cross the spiral conductor 42 may be adopted. In this case, the movable part 66 may be provided with a mechanism for biasing the first contact 54 and the second contact 56 downward while allowing them to move up and down. That is, the first contact 54 and the second contact 56 may be attached to a biasing mechanism that generates a force to push them back downward when pressed upward. In addition, each of the first contact 54 and the second contact 56 may have a shape that protrudes downward in a rounded shape in a plane extending in the radial and vertical directions. This allows the first contact 54 and the second contact 56 to move radially, one pitch at a time, across the spiral conductor 42.

Figure 4 shows contact part 44B according to the second configuration example together with substrate 40, groove 43, and spiral conductor 42. Contact part 44B differs from contact part 44A shown in Figure 3 in that guide rod 52 is replaced with slitted conveying member 70, and that the shape of movable part 72 is adapted to slitted conveying member 70 compared to movable part 66 shown in Figure 3. Slitted conveying member 70 is a roughly rectangular parallelepiped member with the radial direction as the longitudinal direction, with slits 71 cut from the top to the bottom and extending in the radial direction. Movable part 72 engages with slits 71 of slitted conveying member 70 and is freely movable in the radial direction along slits 71.

One end of the slitted transport member 70 is coupled to a rotation drive mechanism 68 provided at the center of the spiral shape of the groove 43 formed in the substrate 40. The slitted transport member 70 extends from the rotation drive mechanism 68 toward the radial outside (positive direction of the r-axis) of the spiral shape of the groove 43. The slitted transport member 70 is rotatable in the circumferential direction (azimuth angle θ direction) along the surface of the substrate 40, with the connection part with the rotation drive mechanism 68 as the center and its longitudinal direction as the radial direction.

The first conducting wire 60 and the second conducting wire 64 are provided inside the slitted conveying member 70 and extend along its longitudinal direction. One radially inner end of the first conducting wire 60 is connected to the first terminal 58, and one radially inner end of the second conducting wire 64 is connected to the second terminal 62. The other ends of the first conducting wire 60 and the second conducting wire 64 may be open.

The conductor connected to the first contact 54 is in slidable contact with the first conductor 60 inside the slitted conveying member 70. The conductor connected to the second contact 56 is in slidable contact with the second conductor 64 inside the slitted conveying member 70. As the slitted conveying member 70 moves in the circumferential direction, the movable part 72 moves in the radial direction so that the first contact 54 and the second contact 56 come into contact with two positions on the spiral conductor 42 that are N pitches apart. The first contact 54 and the second contact 56 slide in the radial direction while in contact with the spiral conductor 42 between two positions on the spiral conductor 42 that are N pitches apart.

The movable part 72 may be provided with a radial drive mechanism 74 that moves the movable part 72 in the radial direction. When the rotation drive mechanism 68 applies a circumferential moving force to the first contact 54 and the second contact 56, which causes a radial moving force to be applied from the groove 43 to the first contact 54 and the second contact 56, thereby moving the first contact 54 and the second contact 56 in the radial direction, the radial drive mechanism 74 does not need to be provided.

Using the same principle as the contact portion 44A shown in FIG. 3, a section of the spiral conductor 42 from a first position to a second position N turns outward around the spiral conductor 42 is connected between the first terminal 58 and the second terminal 62. In the example shown in FIG. 4, a section of the spiral conductor 42 that has made two turns is connected between the first terminal 58 and the second terminal 62.

The first contact 54 and the second contact 56 slide in the circumferential direction while in contact with the first conductor 60 and the second conductor 64, respectively, and the movable part 72 including the first contact 54 and the second contact 56 moves in the radial direction. This changes the section of the spiral conductor 42 through which current flows, i.e., the diameter of the effective coil where the spiral conductor 42 effectively operates as a coil.

In the above, an embodiment has been shown in which the first contact 54 and the second contact 56 slide along the spiral conductor 45 by moving the movable part 72 in the circumferential direction of the spiral conductor 45 while moving it in the radial direction of the spiral conductor 45. In this way, a configuration in which the first contact 54 and the second contact 56 do not slide along the spiral conductor 45, but the first contact 54 and the second contact 56 cross the spiral conductor 45 may be adopted. In this case, the movable part 72 may be provided with a mechanism for biasing the first contact 54 and the second contact 56 downward while allowing them to move up and down. That is, the first contact 54 and the second contact 56 may be attached to a biasing mechanism that generates a force to push them back downward when pressed upward. In addition, each of the first contact 54 and the second contact 56 may have a shape that protrudes downward in a rounded shape in a plane extending in the radial and vertical directions. This allows the first contact 54 and the second contact 56 to move radially, one pitch at a time, across the spiral conductor 42.

Figure 5 shows the variable-diameter coil 14-2 according to the second embodiment. The variable-diameter coil 14-2 includes a substrate 40, a spiral conductor 45, and a switch unit 80. The substrate 40 has a groove 43 formed thereon, which forms a spiral shape so as to shift outward by one pitch for each turn. The spiral conductor 45 is formed on the surface of the groove 43. An inner conductor 48 is formed at the inner end of the spiral conductor 45, and an outer conductor 50 is formed on the outer side of the spiral conductor 45. The spiral conductor 45 in the variable-diameter coil 14-2 differs from the spiral conductor 42 of the variable-diameter coil 14-1 shown in Figure 2 in that a gap G is formed at each turn. Here, the gap refers to a structure in which the spiral conductor 45 is cut and a pair of cut ends formed by the cut face each other. In the example shown in Figure 5, a gap G is formed at each pitch on a straight line extending from the center of the spiral shape formed by the groove 43 toward the radially outward direction.

The switch unit 80 includes a loop selection switch SW provided for each gap G, a first patterned conductor 82, and a second patterned conductor 84. Figure 6 shows a schematic configuration of three loop selection switches SW(j-1), SW(j), and SW(j+1) provided for two turns of the spiral conductor 45. Each loop selection switch SW is controlled by the control unit 18 (Figure 1).

The loop selection switch SW(J) is provided in a gap G formed at the Jth position in the Jth section counting from the inside. Here, J is an integer j-1, j or j+1. Each loop selection switch SW(J) has a contact T1, a contact T2, a contact TM, a first segment S1 and a second segment S2. The contact T1 is connected to one end of the pair of cut ends facing the outside, and the contact T2 is connected to the other end of the pair of cut ends facing the inside. The contact TM is provided in a position insulated from the spiral conductor 45.

The first patterned conductor 82 and the second patterned conductor 84 may be provided on an inner layer or a back surface of the substrate 40. The first patterned conductor 82 and the second patterned conductor 84 extend parallel to the same direction as the direction in which the multiple gaps G formed in the spiral conductor 45 are arranged. A first terminal 58 is connected to one radially outer end of the first patterned conductor 82, and a second terminal 62 is connected to one radially outer end of the second patterned conductor 84. The other radially inner ends of the first patterned conductor 82 and the second patterned conductor 84 may be open.

One end of the first segment S1 of the loop selection switch SW(J) is connected to the contact T1, and the other end selectively contacts either the contact TM or the first pattern conductor 82. In the example shown in FIG. 6, the other end of the first segment S1 of the loop selection switch SW(j-1) contacts the first pattern conductor 82. The first pattern conductor 82 may be provided with a through hole that extends from the first pattern conductor 82 to the surface of the substrate 40. In this case, the other end of the first segment S1 of the loop selection switch SW(j-1) contacts the through hole connected to the first pattern conductor 82. Also, the other end of the first segment S1 of the loop selection switch SW(j) contacts the contact TM.

One end of the second segment S2 of the loop selection switch SW(J) is connected to the contact T2, and the other end selectively contacts either the contact TM or the second pattern conductor 84. In the example shown in FIG. 6, the other end of the second segment S2 of the loop selection switch SW(j+1) contacts the second pattern conductor 84. The second pattern conductor 84 may be provided with a through hole that extends from the second pattern conductor 84 to the surface of the substrate 40. In this case, the other end of the second segment S2 of the loop selection switch SW(j+1) contacts the through hole connected to the second pattern conductor 84. Also, the other end of the second segment S2 of the loop selection switch SW(j) contacts the contact TM.

When the first segment S1 and second segment S2 of each of the loop selection switches SW(j-1) to SW(j+1) are in the state shown in FIG. 6, the following current path is formed. That is, a current path is formed from the first terminal 58 through the first pattern conductor 82 to the j-1th position of the spiral conductor 45, and from the j-1th position to the j+1th position, which is located two turns around the spiral conductor 45 toward the outside. Furthermore, a current path is formed from the j+1th position to the second terminal 62 through the second pattern conductor 84.

In other words, the section of the spiral conductor 45 that extends from the j-1 position to the j+1 position, which is two turns around the spiral conductor 45 toward the outside, is connected between the first terminal 58 and the second terminal 62.

When the spiral conductor 45 makes K turns from one end on the inside to the other end on the outside, j may be any integer between 1 and K-1. The smaller the value of j, the smaller the diameter of the effective coil connected between the first terminal 58 and the second terminal 62, and the larger the value of j, the larger the diameter of the effective coil connected between the first terminal 58 and the second terminal 62.

The above shows an example of operation in which an effective coil of two turns is formed. In this example of operation, the other end of the first segment S1 of the loop selection switch SW(j-1) contacts the first pattern conductor 82, and the other end of the second segment S2 contacts the contact TM. Also, the other ends of the first segment S1 and the second segment S2 of the loop selection switch SW(j) contact the contact TM. Furthermore, the other end of the first segment S1 of the loop selection switch SW(j+1) contacts the contact TM, and the other end of the second segment S2 contacts the second pattern conductor 84.

In the variable diameter coil 14-2, an effective coil of M turns may be formed, where M is an integer equal to or greater than 3. In this case, the other end of the first segment S1 of the loop selection switch SW(j-1) contacts the first patterned conductor 82, and the other end of the second segment S2 contacts the contact TM. Also, the other ends of the first segment S1 and second segment S2 of the loop selection switches SW(j) to SW(j+M-2) contact the contact TM. Furthermore, the other end of the first segment S1 of the loop selection switch SW(j+M-1) contacts the contact TM, and the other end of the second segment S2 contacts the second patterned conductor 84.

Also, the variable diameter coil 14-2 may form an effective coil of one turn. In this case, the other end of the first segment S1 of the loop selection switch SW(j-1) contacts the first pattern conductor 82, and the other end of the second segment S2 contacts the contact point TM. Also, the other end of the first segment S1 of the loop selection switch SW(j) contacts the contact point TM, and the other end of the second segment S2 contacts the second pattern conductor 84.

In this way, in the variable-diameter coil 14-2, the inner switch, which is one of the multiple loop selection switches, connects one of the pair of cut ends facing outward to the first terminal 58. Also, the outer switch, which is one of the multiple loop selection switches and is located outside the inner switch, connects one of the pair of cut ends facing inward to the second terminal 62. Also, the other loop selection switches in the section between the inner switch and the outer switch in the spiral conductor 45 have their pair of cut ends connected.

In the above, a configuration in which a gap G and a loop selection switch SW are provided for each revolution has been shown. The gap G and the loop selection switch SW may be provided in the innermost revolution section and the outermost revolution section, or may be provided for each predetermined revolution.

Figure 7 shows the relationship between the radius and inductance when the number of turns of the spiral conductor 42 and 45 in the variable-diameter coils 14-1 and 14-2 is 12 turns, and a section of the spiral conductor with two turns is used as the effective coil. Under the condition that the current flowing through the effective coil is constant, the larger the radius of the effective coil, the larger the generated magnetic flux, and therefore the larger the inductance.

In the above, an embodiment in which the variable diameter coils 14-1 and 14-2 are used as a power transmission coil in the power transmission device 1 has been shown. The variable diameter coils 14-1 and 14-2 may be used as a power reception coil 30 in the power reception device 2. In this case, the effective coil diameter may be adjusted by adjusting the radial or circumferential position of the movable part (66, 72) in the power reception device 2 so that the received power exceeds a predetermined power threshold. In addition, when a matching circuit including a variable constant element is inserted between the power reception coil 30 and the power reception circuit 32 shown in FIG. 1, the element constant of the variable constant element may be adjusted so that the received power exceeds a predetermined power threshold. In this way, the variable diameter coils 14-1 and 14-2 may be used as a non-contact power supply coil in a non-contact power supply system, that is, as either a power transmission coil or a power reception coil.

According to the variable diameter coil 14 of each of the above embodiments, even in various states of the power receiving device 2 where the distance from the variable diameter coil 14 is different, the coil diameter is kept at an appropriate size, and the matching state between the variable diameter coil 14 and the power supply circuit 10 is appropriately maintained. This improves the efficiency of power transmission from the power transmitting device 1 to the power receiving device 2.

1 Power transmitting device, 2 Power receiving device, 10 Power supply circuit, 12 Matching circuit, 14, 14-1, 14-2 Variable diameter coil, 16 Power transmitting side radio unit, 18 Control unit, 30 Power receiving coil, 32 Power receiving circuit, 34 Power receiving side radio unit, 36 Load circuit, 40 Substrate, 42, 45 Spiral conductor, 43 Groove, 44 Contact portion, 48 Inner conductor, 49 Central recess, 50 Outer conductor, 51 Outer groove, 52 Guide rod, 54 First contact, 56 Second contact, 58 First terminal, 60 First conductor, 62 Second terminal, 64 Second conductor, 66, 72 Movable part, 67 Movable part housing, 68 Rotation drive mechanism, 70 Slitted conveying member, 71 Slit, 74 Radial drive mechanism, 80 Switch unit, 82 First pattern conductor, 84 Second pattern conductor.

Claims (6)

A conductor that draws a spiral shape by shifting one pitch outward each time it goes around.
a first contact that contacts the conductor at a first location on the conductor to connect the conductor to a first terminal;
a second contact that contacts the conductor at a position N circumferences outside the first position and connects the conductor to a second terminal;
a rotation drive mechanism that moves the first contact point and the second contact point in a circumferential direction;
A coil for contactless power supply comprising: A conductor that draws a spiral shape by shifting one pitch outward each time it goes around.
a first contact that contacts the conductor at a first location on the conductor to connect the conductor to a first terminal;
a second contact that contacts the conductor at a position N circumferences outside the first position and connects the conductor to a second terminal;
a radial drive mechanism that moves the first contact and the second contact in a radial direction of the conductor;
A coil for contactless power supply comprising: The coil for contactless power supply according to claim 1 or 2,
A substrate is provided.
The coil for contactless power supply, wherein the conductive wire is formed in a groove formed in a flat surface of a substrate. The conductor is spiral-shaped, shifting outward by one pitch each time it goes around.
a plurality of switches provided at predetermined intervals around the conductor wire;
The conductive wire is
a gap defining a pair of cut ends at each of the switches;
An inner switch of the plurality of switches includes:
One of the pair of cut ends facing outward is connected to a first terminal;
Among the plurality of switches, an outer switch that is located a certain number of revolutions outward from the inner switch is
The other end facing inward is connected to the second terminal ;
The inner switch and the outer switch are selected from a plurality of the switches;
A variable diameter coil for contactless power supply , wherein an effective coil diameter between the first terminal and the second terminal is variable . The variable-diameter coil for contactless power supply according to claim 4 ,
A variable-diameter coil for contactless power supply, characterized in that when there is another switch in the section of the conductor between the inner switch and the outer switch, the other switch is in a state where the pair of cut ends are connected. The variable diameter coil for contactless power supply according to claim 4 or 5,
A substrate is provided.
The variable diameter coil for contactless power supply, wherein the conductive wire is formed in a groove formed in a flat surface of a substrate.

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