JP2011019293A - Power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable power supply system having a simple structure and capable of efficiently supplying power to a rotator.SOLUTION: The power supply system 1 includes a shaft 2 and a bearing 3 for supporting the shaft 2 with a boundary layer 4 sandwiched, and supplies power to a predetermined load 6 from an AC power supply 7 via the shaft 2 and the bearing 3. In this system 1, the bearing 3 includes bearing electrodes 32a, 32b. The shaft 2 includes shaft electrodes 20, 21 arranged contactlessly and oppositely to the bearing electrodes 32a, 32b with the boundary layer 4 sandwiched, the shaft electrodes 20, 21 are arranged so as to oppose the bearing electrodes 32a, 32b to constitute capacitors 8a, 8b. The AC power supply 7 transmits power to the load 6 via the capacitors 8a, 8b.

Description

  The present invention relates to a power supply system for supplying power to various loads.

  In general, a power supply system that supplies power to a load installed on a rotating body is a contact-type power supply that supplies power by bringing an electrode from the outside into contact with an electrode provided on the rotating body so as to be exposed. The system can be broadly classified into a non-contact type power supply system that supplies power without contacting an electrode that is provided in a non-exposed state inside the rotating body.

  Among these, a conventional contact-type power supply system is disclosed in Patent Document 1, for example. In this system, an electrode called a slip ring is provided on the rotating body, and an electrode called a brush is provided outside the rotating body, and electric power is transmitted by contacting and sliding the slip ring and the brush.

  A conventional non-contact power supply system is disclosed in Patent Document 2, for example. In this system, a primary coil is provided on the fixed side, a secondary coil is provided on the rotating body, and the primary coil and the secondary coil are arranged to face each other, for example. Thus, when AC power is supplied to the primary coil, induced electromotive force is generated in the secondary coil, and power is supplied to the load of the rotating body.

JP-A-6-282801 (paragraph "0004") JP 2000-058355 A (paragraph "0002")

  However, in the power supply system described in Patent Document 1, it is necessary to appropriately manage the contact pressure between the brush and the slip ring in order to perform stable power supply. That is, when the contact pressure is higher than the appropriate value, the sliding resistance increases and the wear of the brush and the slip ring is promoted, which may lead to shortening of the device life. Further, when the contact pressure is lower than an appropriate value, there is a possibility that power transmission becomes unstable due to poor contact between the brush and the slip ring. Therefore, in order to ensure reliability, regular maintenance such as replacement and adjustment of parts has been required.

  In addition, in the power supply system described in Patent Document 2, it is necessary to provide a core such as an iron core on the rotating body in order to increase the power feeding efficiency by electromagnetic induction, resulting in a complicated structure and an increase in weight. Moreover, since the secondary coil is deformed by centrifugal force when the rotational speed of the rotating body is increased, it is difficult to apply to a rotating body that rotates at high speed. Further, there is a problem that the frequency of the induced electromotive force generated in the secondary coil varies depending on the number of rotations of the rotating body.

  The present invention has been made in view of the above, and an object of the present invention is to provide a highly reliable power supply system that can efficiently supply power to a rotating body with a simple structure.

  In order to solve the above-described problems and achieve the object, the power supply system according to claim 1 includes a shaft and a bearing that supports the shaft with a boundary layer interposed therebetween, and the AC is exchanged via the shaft and the bearing. A power supply system for supplying power from a power source to a predetermined load, wherein the bearing includes a bearing electrode, and the shaft is opposed to and non-contacting the bearing electrode with the boundary layer interposed therebetween. A coupling capacitor is configured by arranging the shaft electrode so as to face the bearing electrode, and the AC power supply transmits power to the load via the coupling capacitor.

  The power supply system according to claim 2 is the power supply system according to claim 1, wherein the bearing includes the first bearing electrode and the second bearing electrode to which power is supplied, The shaft includes the first shaft electrode and the second shaft electrode, and the first shaft electrode is disposed so as to face the first bearing electrode, whereby the first coupling capacitor is configured. In addition, the second coupling electrode is configured by disposing the second shaft electrode so as to face the second bearing electrode, and the AC power supply includes the first coupling capacitor and the second coupling capacitor. Power is transmitted to the load through two coupling capacitors.

  The power supply system according to claim 3 is the power supply system according to claim 2, wherein the shaft or the bearing includes a first coil connected in series to the first coupling capacitor, and a first coil. A second coil connected in series to two coupling capacitors, and the AC power source is in series resonance with the first coupling capacitor and the first coil, and the second coupling capacitor and the second coil. Is transmitted to the load via the first coupling capacitor and the second coupling capacitor.

  The power supply system according to claim 4 is the power supply system according to claim 3, wherein the bearing includes a plurality of the first bearing electrodes, and the shaft includes a plurality of the first shafts. A plurality of the first coupling capacitors are configured by disposing the plurality of first shaft electrodes so as to face the plurality of first bearing electrodes, and the shaft or the bearing includes: A plurality of the first coils connected in series for each of the plurality of first coupling capacitors; and the AC power supply includes the plurality of first coupling capacitors, the plurality of first coils, and the second coil. Power transmission to the plurality of loads is performed via the plurality of first coupling capacitors and the second coupling capacitor under conditions that cause series resonance in the coupling capacitor and the second coil.

  The power supply system according to claim 5 is the power supply system according to any one of claims 1 to 4, wherein the shaft electrode is formed in a male screw shape, and the bearing electrode is formed of the shaft. It is formed in a female screw shape that is screwed into the male screw shape of the electrode.

  The power supply system according to claim 6 is the power supply system according to claim 2, wherein the shaft is connected in parallel between the first shaft electrode and the second shaft electrode. A first capacitor and a third coil, wherein the AC power source is configured to generate a parallel resonance between the first capacitor and the third coil, and the first coupling capacitor and the second coupling. Power is transmitted to the load through a capacitor.

  According to the power supply system of the first aspect, since it is not necessary to directly contact the bearing electrode and the shaft electrode, it is not necessary to consider the control of contact pressure between the electrodes, wear of the electrode, etc. Reliability can be easily increased. Moreover, since it is not necessary to provide a core material, a coil, etc. in a rotary body, the complexity of a structure and a weight increase can be avoided. Furthermore, the advantage that the electric power supplied to the rotating body is not affected by the rotation speed can be obtained. In addition, the bearing electrode disposed on the inner peripheral surface of the bearing and the shaft electrode disposed on the outer peripheral surface of the shaft are opposed to each other and in a non-contact manner with a boundary layer of bearing lubricating oil or lubricating resin interposed therebetween. Since they are arranged, the power supply system can be configured with a simple and highly reliable structure by utilizing the mechanical structure of the conventional plain bearing.

  Further, according to the power supply system of the second aspect, the first coupling capacitor is configured by arranging the first shaft electrode so as to face the first bearing electrode, and the second coupling capacitor Since the second coupling capacitor is configured by disposing the second shaft electrode so as to face the bearing electrode, power is transmitted to the load via the first coupling capacitor and the second coupling capacitor. A closed circuit using an AC power supply, a first coupling capacitor, a load, and a second coupling capacitor can be configured.

  According to a third aspect of the present invention, the first coupling capacitor and the first coil and the second coupling capacitor and the second coil generate the first resonance under a condition that causes series resonance. Since power is transmitted to the load through the capacitor and the second coupling capacitor, the impedance of the power supply circuit can be minimized and the power supply efficiency can be improved.

  Further, according to the power supply system of the fourth aspect of the present invention, under the condition that the plurality of first coupling capacitors and the plurality of first coils and the second coupling capacitor and the second coil generate series resonance, Since power is transmitted to a plurality of loads via a plurality of first coupling capacitors and a second coupling capacitor, power is individually supplied to a plurality of loads provided on the rotating body via a bearing and a shaft. can do.

  According to the power supply system of claim 5, the shaft electrode is formed in a male screw shape, and the bearing electrode is formed in a female screw shape that is screwed into the male screw shape of the shaft electrode. Even for a load connected to a nut that moves with the rotation, power can be supplied via a shaft electrode provided on the feed screw and a bearing electrode provided on the nut.

  According to the power supply system of the sixth aspect, the first capacitor and the third coil provided so as to be connected in parallel between the first shaft electrode and the second shaft electrode, Since power is transmitted to the load through the first coupling capacitor and the second coupling capacitor under the condition of generating parallel resonance in the first parallel capacitor, the first parallel circuit configured by the first capacitor and the third coil is used. The impedance of the circuit on the shaft side including the resonance circuit and the load can be increased. As a result, a voltage drop in the coupling capacitor can be reduced, and stable power supply can be achieved regardless of variations in the capacitance of the coupling capacitor.

1 is a schematic diagram conceptually showing a power supply system according to a first embodiment. FIG. 2A is a longitudinal sectional view of a power supply system, FIG. 2A is a longitudinal sectional view showing a first shaft and a first bearing, and FIG. 2B is a longitudinal sectional view showing a second shaft and a second bearing. FIG. It is the figure which simplified and showed the circuit structure of the electric power supply system. It is a cross-sectional view which simplifies and shows the electric power supply system which concerns on Embodiment 2. FIG. It is the figure which showed the circuit structure of the electric power supply system of FIG. 6 is a plan view showing a power supply system according to Embodiment 3. FIG. It is AA sectional drawing of the electric power supply system shown in FIG. It is the figure which showed the circuit structure of the electric power supply system which concerns on this Embodiment 4. FIG. FIG. 10 is a perspective view schematically showing a power supply system according to a fifth embodiment. It is BB sectional drawing of the electric power supply system shown in FIG. FIG. 10 is a cross-sectional view of a power supply system according to a sixth embodiment.

  Embodiments of a power supply system according to the present invention will be described below in detail with reference to the accompanying drawings. First, [I] the basic concept common to each embodiment was explained, then [II] the specific contents of each embodiment were explained, and [III] finally, a modification to each embodiment was explained. To do. However, the present invention is not limited by these embodiments.

[I] Basic concept common to the embodiments First, the basic concept common to the embodiments will be described. The power supply system according to each embodiment is a power supply system for supplying power to a predetermined load provided on a rotating body that rotates relative to a power source. The application target of this power supply system is arbitrary, for example, when supplying power to an arm of an industrial robot, when supplying power to a surveillance camera that swings, or when supplying power to a rotating part of a tower crane For example, the present invention can be applied to supply electric power to a rotating body through a rotary connecting portion composed of a shaft and a bearing.

  This power supply system supplies power in a non-contact manner between a shaft and a bearing that rotate relatively around a predetermined shaft. This non-contact power supply is generally performed using a capacitor disposed with a boundary layer provided between the shaft and the bearing. That is, a capacitor (hereinafter referred to as a “coupled capacitor”) is formed by disposing the shaft electrode disposed on the shaft and the bearing electrode disposed on the bearing so as to face each other and contact each other across the boundary layer. ). At least two such coupling capacitors are provided and arranged in the power transmission path, and electric field type power transmission is performed through the two coupling capacitors. According to this configuration, since it is not necessary to bring the shaft electrode and the bearing electrode into contact with each other, there is no need to consider contact pressure management, electrode wear, and the like, and the power supply reliability can be easily increased. Moreover, since it is not necessary to provide a core material, a coil, etc. in a rotary body, complication of a structure and weight increase can be avoided. Furthermore, the advantage that the electric power supplied to the rotating body is not affected by the rotation speed can be obtained.

[II] Specific Contents of Each Embodiment Next, specific contents of each embodiment of the power supply system will be described.

[Embodiment 1]
First, the first embodiment will be described. In the first embodiment, a bearing electrode is disposed on the inner peripheral surface of the bearing, and a shaft electrode is disposed on the outer peripheral surface of the shaft.

(Constitution)
First, the configuration of the power supply system will be described. FIG. 1 is a schematic diagram conceptually showing the power supply system according to the first embodiment. FIG. 2 is a longitudinal sectional view of the power supply system, FIG. 2 (a) is a longitudinal sectional view showing the shaft and the first bearing, and FIG. 2 (b) is a longitudinal sectional view showing the shaft and the second bearing. . As shown in FIG. 1, the power supply system 1 includes a shaft 2, a bearing 3 that supports the shaft 2, and a boundary layer 4 that is sandwiched between the shaft 2 and the bearing 3. The electric power supply system 1 supplies electric power from an AC power supply 7 provided outside the bearing 3 to the load 6 provided on the rotating body 5 that rotates together with the shaft 2 via the bearing 3 and the shaft 2. .

(Configuration-axis)
As shown in FIG. 1, the shaft 2 includes a first shaft electrode 20, a second shaft electrode 21, a load 6, and a power line 22. Hereinafter, when it is not necessary to distinguish the first shaft electrode 20 and the second shaft electrode 21 from each other, these are simply collectively referred to as “shaft electrodes 20 and 21”.

  The shaft electrodes 20 and 21 transmit electric power to and from the bearing 3. As shown in FIG. 2, the shaft electrodes 20 and 21 are arranged on the outer peripheral surface of the shaft 2, and the first shaft electrode 20 is non-conductive with respect to a first bearing electrode 32a described later. The second shaft electrode 21 is disposed so as to be opposed and non-contact with the boundary layer 4 interposed therebetween, and the second shaft electrode 21 is disposed so as to be opposed and non-contact with the second bearing electrode 32b described later with the boundary layer 4 interposed therebetween. The shaft electrodes 20 and 21 are formed in a substantially cylindrical shape using a conductive material such as metal, and are fixed to the outer peripheral surface of the shaft 2. The method of fixing the bearing electrodes 32a and 32b to the shaft 2 is arbitrary. For example, the bearing electrodes 32a and 32b may be fitted to the outer periphery of the shaft 2 through a nonconductive spacer such as plastic or fixed using a nonconductive adhesive. The shaft electrodes 20 and 21 are fixed to the shaft 2 while maintaining insulation between the shaft electrodes 20 and 21 and the shaft 2. The axial electrodes 20 and 21 are continuous over a range of 360 degrees centered on the axis when viewed in a cross section of the axis electrodes 20 and 21 by a plane orthogonal to the axis of the axis 2. However, it may be formed discontinuously within a range of less than 360 degrees as long as a desired capacity can be obtained as the capacity of capacitors 8a and 8b described later. For example, when the shafts 20 and 21 are formed by bending a metal flat plate into a cylindrical shape, if it is difficult for some reason to join the ends of the bent metal flat plates to each other, the end The parts may be separated without being joined to each other.

  Returning to FIG. 1, the load 6 is driven by AC power supplied via the shaft electrodes 20 and 21 and exhibits a predetermined function. For example, when the shaft 2 is configured as a part of the joint of the robot arm, the load 6 corresponds to a motor or a control unit built in the robot arm extended from the joint including the shaft 2. In addition, the specific configuration of the load 6 is arbitrary. For example, the load 6 can be configured as a monitoring camera that swings with the rotation of the shaft 2 or a tower crane that rotates with the shaft 2. The load 6 is not necessarily provided inside the shaft 2, and the load 6 is provided on the rotating body 5 including the shaft 2 and power is supplied to the load 6 via the shaft 2. Good. In addition, although only one load 6 is shown in FIG. 1, power may be supplied to a plurality of loads 6 connected in series or in parallel to each other.

  The power line 22 is an electrical wiring for transmitting power from the shaft electrodes 20 and 21 to the load 6. The specific configuration of the power line 22 is arbitrary. For example, the power line 22 is wired inside the shaft 2 using a conductive wire insulated by a covering material.

(Configuration-Bearing)
As shown in FIG. 1, the bearing 3 includes a first bearing 3a and a second bearing 3b. Hereinafter, when it is not necessary to distinguish the first bearing 3a and the second bearing 3b from each other, these are simply referred to as “bearings 3”. As shown in FIG. 2, the bearing 3 includes a fixing base 30 and a conductive fixing portion 31. Further, the first bearing 3a includes a first bearing electrode 32a and a first coil 33a (inductor), and the second bearing 3b includes a second bearing electrode 32b and a second coil 33b.

  The fixed base 30 is a base for fixing the bearing 3 to a fixed object (not shown), and is formed using a non-conductive material such as plastic, for example. The fixing method to a fixed object is arbitrary, for example, the fixing base 30 is fixed to a fixed object using a volt | bolt and a nut. Alternatively, the bearing 3 is press-fitted and fixed in a bearing installation hole provided in the fixed object.

  The conductive fixing portion 31 is for mechanically reinforcing the first bearing electrode 32 a and the second bearing electrode 32 b and fixing the first bearing electrode 32 a and the second bearing electrode 32 b to the bearing 3. As shown in FIG. 2, the conductive fixing portion 31 is formed in a substantially cylindrical shape using a conductive material such as metal, and is press-fitted into a press-fitting hole provided in the fixing base 30 and fixed. However, the conductive fixing portion 31 may be integrally formed with the first bearing electrode 32a and the second bearing electrode 32b.

  The first bearing electrode 32 a and the second bearing electrode 32 b are bearing electrodes to which electric power is supplied from the AC power supply 7, and the first bearing electrode 32 a and the second bearing electrode 32 b are first on the inner peripheral surface of the first bearing 3 a facing the outer peripheral surface of the shaft 2. The second bearing electrode 32b is disposed on the inner peripheral surface of the second bearing 3b facing the outer peripheral surface of the shaft 2. Hereinafter, when it is not necessary to distinguish the first bearing electrode 32a and the second bearing electrode 32b from each other, these are simply collectively referred to as “bearing electrodes 32a and 32b”. The bearing electrodes 32 a and 32 b are formed in a substantially cylindrical shape using a conductive material such as metal and are fixed to the inner peripheral surface of the conductive fixing portion 31. The method for fixing the bearing electrodes 32a and 32b is arbitrary, but electrical continuity is maintained between the bearing electrodes 32a and 32b and the conductive fixing portion 31 by fixing by press-fitting or fixing using a conductive adhesive. In addition, as shown in FIG. 1, the first bearing electrode 32a is connected to the AC power source 7 via the first coil 33a, and the second bearing electrode 32b is connected to the GND via the second coil 33b. The bearing electrode 32a, 32b is supplied with electric power from the AC power source 7.

(Configuration-boundary layer)
The boundary layer 4 is sandwiched between the shaft 2 and the bearing 3 and is slidable with respect to at least one of the shaft 2 or the bearing 3. As the boundary layer 4, for example, a non-conductive material such as a bearing lubricating oil or a lubricating resin (tetrafluoroethylene resin (PTFE), polyphenylene sulfide (PPS), etc.) generally used for a sliding bearing is used. Can be used. That is, the boundary layer 4 is a capacitor layer for forming capacitors 8a and 8b, which will be described later, between the shaft electrodes 20 and 21 and the bearing electrodes 32a and 32b, and the shaft electrodes 20 and 21 and the bearing electrodes 32a and 32b. It is an insulating layer which prevents a short circuit.

  In this state, the first coupling capacitor 8a is configured by disposing the first shaft electrode 20 so as to face the first bearing electrode 32a with the non-conductive boundary layer 4 interposed therebetween, and the non-conductive The second coupling capacitor 8b is configured by arranging the second shaft electrode 21 so as to face the second bearing electrode 32b with the boundary layer 4 interposed therebetween. Hereinafter, when it is not necessary to distinguish the first coupling capacitor 8a and the second coupling capacitor 8b from each other, these are simply collectively referred to as “capacitors 8a and 8b”.

  As shown in FIG. 1, the first coil 33a is arranged in series with the first coupling capacitor 8a, and the second coil 33b is arranged in series with the second coupling capacitor 8b. Hereinafter, when it is not necessary to distinguish the first coil 33a and the second coil 33b from each other, they are simply referred to as “coils 33a and 33b”. These coils 33a and 33b constitute a series resonance circuit with the capacitors 8a and 8b to enable power transmission by series resonance. These coils 33a and 33b can take any configuration and arrangement as long as series resonance is possible. For example, the coils 33a and 33b may be arranged on the shaft 2 but are arranged on the bearing 3 here. Thereby, complication of the structure of the rotating body 5 including the shaft 2 and an increase in weight can be prevented.

(Function)
Next, the operation of the power supply system 1 configured as described above will be described. FIG. 3 is a diagram showing a simplified circuit configuration of the power supply system 1.

  When the series resonance condition in the series resonance circuit constituted by the capacitors 8a and 8b, the coils 33a and 33b, and the load 6 shown in FIG. 3 is satisfied, series resonance occurs, and the boundary layers 4 are arranged in contact with each other with the boundary layer 4 interposed therebetween. Electric power is supplied to the load 6 via the bearing 3 and the shaft 2. Specifically, when the circuit shown in FIG. 3 is represented by an equivalent circuit (not shown) including a capacitor having a capacitance C, a coil having an inductance L, and a load having a resistance R, the resonance frequency f is f. = 1 / (2π√LC). When AC power is output from the AC power source 7 at the resonance frequency f, series resonance occurs. In this case, since the impedance of the power supply circuit is minimized, the power supply efficiency can be improved.

(Effect of Embodiment 1)
As described above, according to the first embodiment, it is not necessary to directly contact the bearing electrodes 32a and 32b and the shaft electrodes 20 and 21, and therefore, it is not necessary to consider the management of the contact pressure between the electrodes and the wear of the electrodes. In addition, the reliability of power supply can be easily increased. Moreover, since it is not necessary to provide a core material, a coil, etc. in the rotary body 5, complication of a structure and weight increase can be avoided. Furthermore, the advantage that the electric power supplied to the rotary body 5 is not influenced by the rotation speed can also be obtained. In addition, bearing electrodes 32a and 32b disposed on the inner peripheral surface of the bearing 3 and the shaft electrode 20 disposed on the outer peripheral surface of the shaft 2 with the boundary layer 4 made of bearing lubricating oil, lubricating resin, or the like interposed therebetween. The power supply system 1 can be configured with a simple and highly reliable structure by utilizing the mechanical structure of the conventional plain bearing.

  Further, the first coupling electrode 8a is configured by disposing the first shaft electrode 20 so as to face the first bearing electrode 32a, and the second so as to face the second bearing electrode 32b. The second coupling capacitor 8b is configured by arranging the shaft electrode 21 and power is transmitted to the load 6 through the first coupling capacitor 8a and the second coupling capacitor 8b. A closed circuit using the first coupling capacitor 8a, the load 6, and the second coupling capacitor 8b can be configured.

  Further, the first coupling capacitor 8a and the second coupling capacitor 8b are provided on the condition that series resonance occurs in the first coupling capacitor 8a and the first coil 33a, the second coupling capacitor 8b, and the second coil 33b. Therefore, the impedance of the power supply circuit can be minimized and the power supply efficiency can be improved.

[Embodiment 2]
Next, a second embodiment will be described. In this embodiment, a plurality of bearing electrodes 32a and 32b and a plurality of shaft electrodes 20 and 21 are provided in addition to the configuration of the first embodiment. The configuration of the second embodiment is substantially the same as the configuration of the first embodiment unless otherwise specified, and the same configuration as that of the first embodiment is the same as that used in the first embodiment. The code | symbol and / or name are attached | subjected as needed, and the description is abbreviate | omitted.

(Constitution)
4 is a cross-sectional view schematically showing the power supply system 1 according to the second embodiment, and FIG. 5 is a diagram showing a circuit configuration of the power supply system 1 of FIG. As shown in FIGS. 4 and 5, the power supply system 1 according to the second embodiment is provided outside the bearing 3 with respect to a plurality of loads 6 provided on the rotating body 5 including the shaft 2. In addition, power is supplied from the plurality of AC power sources 7 through the bearing 3 and the shaft 2.

(Configuration-axis)
As shown in FIG. 4, the shaft 2 includes a plurality of first shaft electrodes 20, and a load 6 is connected between each of the first shaft electrodes 20 and the second shaft electrodes 21. Yes.

  As shown in FIG. 5, the shaft 2 according to the second embodiment includes a communication unit 9. The communication unit 9 is a communication unit that communicates with a communication unit 9 (described later) provided on the bearing 3. Although the specific configuration of the communication unit 9 is arbitrary, for example, the communication unit 9 is configured using RF / MAC that performs RF communication using the MAC protocol (the same applies to the communication unit 9 of the bearing 3 described later). The communication unit 9 acquires a communication signal from the line via the communication coupling capacitor 9a or outputs the communication signal superimposed on the line. In this power supply system 1, a frequency of about 1 MHz is used for power supply, but it is assumed that a frequency band near several GHz is used for communication using the communication unit 9. It is considered that the capacitances of the capacitors 8a and 8b are sufficiently large with respect to the communication frequency and do not cause a transmission loss.

(Configuration-Bearing)
As shown in FIG. 4, the first bearing 3a includes a plurality of first bearing electrodes 32a, and includes a conductive fixing portion 31 for each of the plurality of first bearing electrodes 32a. The plurality of conductive fixing portions 31 are insulated from each other, for example, by being arranged on the non-conductive fixing base 30 with a predetermined interval therebetween. In addition, since the first bearing electrodes 32a are fixed to the conductive fixing portions 31 thus insulated from each other, the insulation between the first bearing electrodes 32a is also ensured.

  In this state, the plurality of first coupling capacitors 8a are configured by disposing the plurality of first shaft electrodes 20 so as to face the plurality of first bearing electrodes 32a.

  A first coil 33a is connected in series for each of the plurality of first coupling capacitors 8a. Each of the plurality of first coils 33a forms a series resonance circuit with the first coupling capacitor 8a, and enables power transmission by series resonance.

  As shown in FIG. 5, the bearing 3 according to the second embodiment includes a communication unit 9. The communication unit 9 is a communication unit that communicates with the communication unit 9 provided on the shaft 2. The communication unit 9 acquires a communication signal output from the communication unit 9 of the shaft 2 from the line via a communication signal coupling capacitor, or superimposes and outputs a communication signal for the communication unit 9 of the shaft 2 on the line. Accordingly, for example, a control signal input from a control unit (not shown) provided outside the bearing 3 is transmitted from the communication unit 9 of the bearing 3 to the communication unit 9 of the shaft 2, and the received control signal is transmitted to the shaft 2 can be input to a control object (not shown) provided on the rotating body 5, and the control object on the rotating body 5 can be controlled via the bearing 3 and the shaft 2. .

(Effect of Embodiment 2)
As described above, according to the second embodiment, the plurality of first coupling capacitors 8a, the plurality of first coils 33a, the second coupling capacitor 8b, and the second coil 33b are caused to generate series resonance. Since power is transmitted to the plurality of loads 6 via the plurality of first coupling capacitors 8a and the second coupling capacitor 8b, the bearing 3 and the shaft 2 are connected to the plurality of loads 6 provided on the rotating body 5. Power can be supplied individually via

  In addition, since the communication unit 9 that superimposes and outputs the communication signal on the line is provided, communication with the rotating body 5 can be performed via the bearing 3 and the shaft 2.

[Embodiment 3]
Next, Embodiment 3 will be described. In this embodiment, in addition to the configuration of the first embodiment, the shaft electrodes 20 and 21 and the bearing electrodes 32a and 32b are formed in a screw shape. The configuration of the third embodiment is substantially the same as the configuration of the first embodiment unless otherwise specified, and the same configuration as that of the first embodiment is the same as that used in the first embodiment. The code | symbol and / or name are attached | subjected as needed, and the description is abbreviate | omitted.

(Constitution)
FIG. 6 is a plan view showing the power supply system 1 according to the third embodiment. As shown in FIG. 6, the power supply system 1 according to Embodiment 3 includes two shafts 2 formed as feed screws. The two shafts 2 are connected to each other via a synchronization chain 10 and rotate in synchronization with each other as the motor 11 rotates. Of these two shafts 2, the shaft 2 that is not directly connected to the motor 11 is referred to as a first shaft 2a, and the shaft 2 that is directly connected to the motor 11 is referred to as a second shaft 2b. In addition, the power supply system 1 according to the third embodiment includes a support bearing 12 that supports only the shaft 2 without transmitting power to the shaft 2. Further, nuts 13 are screwed onto the respective shafts 2, and a moving body 14 including a load 6 is fixed to these nuts 13. The rotational motion of the shaft 2 accompanying the rotation of the motor 11 is converted into a linear motion via the nut 13 so that the moving body 14 can move in the axial direction.

(Configuration-axis)
FIG. 7 is a cross-sectional view of the power supply system 1 shown in FIG. The two shafts 2 according to the third embodiment are formed as feed screws as described above. In a range where the nut 13 moves on the shaft 2, the shaft electrodes 20 and 21 are formed in a male screw shape as a part of the feed screw and are fixed to the outer peripheral surface of the shaft 2. Further, the shaft electrodes 20 and 21 are implemented for the portion of the first shaft 2a supported by the first bearing 3a and the portion of the second shaft 2b supported by the second bearing 3b. As in the case of the first embodiment, it is formed in a substantially cylindrical shape and is fixed to the outer peripheral surface of the shaft 2. Further, the male screw-shaped portion and the substantially cylindrical portion of the shaft electrodes 20, 21 are electrically connected to each other.

  On the other hand, the shaft electrodes 20 and 21 are not provided for the portions of the shafts 2 that are supported by the support bearings 12, and the space between the shafts 2 and the support bearings 12 is separated by non-conductive spacers or the like. It is electrically insulated. Similarly, the synchronization chain 10 and the shaft 2 are electrically insulated. Thereby, electric power is transmitted only between the bearing 3 and the shaft 2 and between the shaft 2 and the nut 13.

(Configuration-nut)
The nut 13 includes a conductive fixing portion 31 and bearing electrodes 32a and 32b. Since the conductive fixing portion 31 is the same as the conductive fixing portion 31 of the bearing 3 in the first embodiment, the description thereof is omitted.

  The bearing electrodes 32 a and 32 b are supplied with electric power from the AC power source 7 through the shaft 2, and the bearing electrodes 32 a and 32 b are arranged on the inner peripheral surface of the nut 13 facing the outer peripheral surface of the shaft 2. . The bearing electrodes 32 a and 32 b are formed in a female screw shape that is screwed into the male screw shape of the shaft electrodes 20 and 21 using a conductive material such as metal, for example, and the inner periphery of the conductive fixing portion 31 of the nut 13. It is fixed to the surface. The bearing electrodes 32 a and 32 b are arranged in a non-contact manner and in contact with the shaft electrodes 20 and 21 with the nonconductive boundary layer 4 interposed therebetween.

  A load 6 is connected between the nut 13 screwed to the first shaft 2a and the nut 13 screwed to the second shaft 2b. The load 6 is electrically connected to the bearing electrodes 32a and 32b of the nut 13 and is driven by AC power supplied through the bearing electrodes 32a and 32b.

  In this state, the third coupling capacitor 8c is configured by disposing the first shaft electrode 20 so as to face the bearing electrodes 32a and 32b of the nut 13 with the nonconductive boundary layer 4 interposed therebetween. The fourth coupling capacitor 8d is configured by disposing the second shaft electrode 21 so as to face the second bearing electrode 32b with the conductive boundary layer 4 interposed therebetween. Hereinafter, when there is no need to distinguish the third coupling capacitor 8c and the fourth coupling capacitor 8d from each other, these are simply referred to as “nut-side capacitors 8c, 8d”.

(Function)
Next, the operation of the power supply system 1 configured as described above will be described. When the series resonance condition in the series resonance circuit configured by the capacitors 8a and 8b, the coils 33a and 33b, the nut-side capacitors 8c and 8d, and the load 6 shown in FIG. 6 is satisfied, series resonance occurs and the boundary layer 4 is sandwiched. Electric power is supplied to the load 6 through the bearing 3, the shaft 2, and the nut 13 that are arranged in contact with each other.

(Effect of Embodiment 3)
As described above, according to the third embodiment, the shaft electrode of the shaft 2 formed as a feed screw is formed into a male screw shape, and the bearing electrodes 32a and 32b of the nut 13 screwed into the feed screw are used as shafts. Since the electrodes 20 and 21 are formed in a female screw shape that is screwed into the male screw shape, power can be supplied to the load 6 connected to the nut 13 that moves as the feed screw rotates.

[Embodiment 4]
Next, a fourth embodiment will be described. In this form, a parallel resonant circuit is configured using a capacitor and a coil. The configuration of the fourth embodiment is substantially the same as the configuration of the first embodiment unless otherwise specified, and the same configuration as that of the first embodiment is the same as that used in the first embodiment. The code | symbol and / or name are attached | subjected as needed, and the description is abbreviate | omitted.

(Constitution)
FIG. 8 is a diagram showing a circuit configuration of the power supply system 1 according to the fourth embodiment.

(Configuration-axis)
As shown in FIG. 8, the shaft 2 according to the fourth embodiment includes a first parallel resonant circuit 40 and a second parallel resonant circuit 50 in addition to the shaft electrodes 20 and 21, the load 6, and the power line 22. ing.

  The first parallel resonance circuit 40 is connected to the first shaft electrode 20 and the second shaft electrode 21, and includes a first capacitor 41 and a third coil 42. The first capacitor 41 and the third coil 42 are connected in parallel to each other between the first shaft electrode 20 and the second shaft electrode 21 to constitute a parallel resonance circuit.

  The second parallel resonant circuit 50 is connected to the load 6 and includes a second capacitor 51 and a fourth coil 52. The second capacitor 51 and the fourth coil 52 are connected in parallel to each other to constitute a parallel resonance circuit.

  The third coil 42 and the fourth coil 52 are arranged in parallel with each other at a predetermined interval, and power is transmitted between the third coil 42 and the fourth coil 52 by mutual induction. Is arranged to be possible. Further, in order to transform the input voltage to the shaft electrodes 20 and 21 with a desired transformation ratio and supply it to the load 6, the turn ratio between the third coil 42 and the fourth coil 52 is set.

(Configuration-Bearing)
As shown in FIG. 8, the bearing 3 according to the fourth embodiment includes a third parallel resonance circuit 60 and a fourth parallel resonance circuit 70.

  The third parallel resonance circuit 60 is connected to the AC power supply 7 and includes a third capacitor 61 and a fifth coil 62. The third capacitor 61 and the fifth coil 62 are connected in parallel to each other to constitute a parallel resonance circuit.

  The fourth parallel resonance circuit 70 is connected to the first bearing electrode 32 a and the second bearing electrode 32 b, and includes a fourth capacitor 71 and a sixth coil 72. The fourth capacitor 71 and the sixth coil 72 constitute a parallel resonance circuit by being connected in parallel between the first bearing electrode 32a and the second bearing electrode 32b. The fifth coil 62 and the sixth coil 72 are arranged in parallel with each other at a predetermined interval, and power is transmitted between the fifth coil 62 and the sixth coil 72 by mutual induction. Is arranged to be possible. Further, in order to boost the output voltage of the AC power supply 7 at a desired transformation ratio and supply the boosted voltage to the bearing electrodes 32a and 32b, the turn ratio between the fifth coil 62 and the sixth coil 72 is set.

Here, in each parallel resonant circuit, the parallel resonant frequencies f _{1 of} the first parallel resonant circuit 40, the second parallel resonant circuit 50, the third parallel resonant circuit 60, and the fourth parallel resonant circuit 70 are equal to each other. The capacitance of the capacitor and the inductance of the coil are set. Accordingly, by outputting AC power from the AC power source 7 under the condition for generating parallel resonance in these parallel resonance circuits (that is, by outputting AC power from the AC power source 7 at the parallel resonance frequency f ₁ ), each parallel resonance is generated. Parallel resonance occurs in the circuit.

(Function)
Next, the operation of the power supply system 1 configured as described above will be described. When AC power is output from the AC power supply 7 at a parallel resonance frequency f ₁ common to each parallel resonance circuit and the parallel resonance condition is satisfied, parallel resonance occurs in the parallel resonance circuit. In this case, since the impedance of the parallel resonance circuit becomes extremely large at the parallel resonance frequency, the impedance of the shaft side circuit including the first parallel resonance circuit 40, the second parallel resonance circuit 50, and the load 6 in which the parallel resonance has occurred is obtained. The impedance of the capacitors 8a and 8b can be made extremely large, and the influence on the power supply due to the variation of the capacitance of the capacitors 8a and 8b can be reduced. Thereby, for example, even when the distance between the shaft 2 and the bearing 3 varies due to the swing of the shaft 2 and the capacitances of the capacitors 8a and 8b vary, the distance between the shaft 3 and the shaft 2 can be stabilized stably. Electric power can be supplied to the load 6. Further, by providing the second parallel resonance circuit 50 and the third parallel resonance circuit 60, the reactive current output from the AC power supply 7 is reduced.

(Effect of Embodiment 4)
As described above, according to the fourth embodiment, the first capacitor 41 and the third coil 42 provided so as to be connected in parallel with each other between the first shaft electrode 20 and the second shaft electrode 21. Since power is transmitted to the load 6 through the first coupling capacitor 8a and the second coupling capacitor 8b under the condition of generating parallel resonance in the first and second capacitors, the first capacitor 41 and the third coil 42 are used. The impedance of the circuit on the side of the shaft 2 including the first parallel resonant circuit 40 and the load 6 to be increased can be increased. Thereby, the voltage drop in the capacitors 8a and 8b can be reduced, and stable power supply can be achieved regardless of the variation in the capacitance of the capacitors 8a and 8b.

[Embodiment 5]
Next, a fifth embodiment will be described. In this form, a coupling capacitor is provided in a plane orthogonal to the axis 2. The configuration of the fifth embodiment is substantially the same as the configuration of the first embodiment except where otherwise specified. The configuration substantially the same as that of the first embodiment is the same as that used in the first embodiment. The code | symbol and / or name are attached | subjected as needed, and the description is abbreviate | omitted.

(Constitution)
FIG. 9 is a perspective view schematically showing the power supply system 1 according to the fifth embodiment, and FIG. 10 is a cross-sectional view taken along line BB of the power supply system 1 shown in FIG. As shown in FIGS. 9 and 10, the power supply system 1 according to the fifth embodiment includes a fixed body 100, a rotating body 110, and a boundary layer 120. The power supply system 1 supplies power to a load 113 provided on the rotating body 110 from an AC power supply 7 that is stationary relative to the fixed body 100.

(Configuration-fixed body)
The fixed body 100 includes a bearing 101, a first electrode 102, and coils 33a and 33b. The bearing 101 supports a shaft of a rotating body 110 to be described later. For example, a known bearing such as a sliding bearing or a rolling bearing can be used. The first electrode 102 is an electrode to which electric power is supplied from the AC power source 7, and is connected to the GND through the first electrode 102 connected to the AC power source 7 through the first coil 33a and the second coil 33b. And a first electrode 102 to be connected.

(Configuration-rotating body)
The rotating body 110 includes a shaft 111, an electrode fixing plate 112, and a load 113. The shaft 111 is supported by the bearing 101 and rotates relative to the fixed body 100.

  The electrode fixing plate 112 is a substantially circular plate fixedly provided in a plane orthogonal to the shaft 111 with the shaft 111 as a center, and is configured using a non-conductive material. As shown in FIG. 10, two second electrodes 114 are provided on the electrode fixing plate 112. Arrangement of these second electrodes 114 is arbitrary. For example, as shown in FIG. 10A, one second electrode 114 is provided on one surface of the electrode fixing plate 112 and on the outer peripheral side of the electrode fixing plate 112. The other second electrode 114 is disposed on the other surface of the electrode fixing plate 112 and on the inner peripheral side of the electrode fixing plate 112. Thereby, the electrostatic capacitance between the two 2nd electrodes 114 can be reduced, and the loss in electric power supply can be reduced. Alternatively, as shown in FIG. 10B, one second electrode 114 is disposed on one entire surface of the electrode fixing plate 112, and the other second electrode 114 is disposed on the other surface. In this case, the capacitance between the two second electrodes 114 can be reduced by taking a sufficient thickness of the electrode fixing plate 112.

  The load 113 is connected between the two second electrodes 114, is driven by the AC power supplied via the second electrode 114, and exhibits a predetermined function.

(Configuration-boundary layer)
The boundary layer 120 is sandwiched between the first electrode 102 and the second electrode 114 and is installed so as to be rotatable with respect to at least one of the shaft 111 and the bearing 101. As the boundary layer 120, for example, a non-conductive material such as a bearing lubricating oil or a lubricating resin (tetrafluoroethylene resin (PTFE), polyphenylene sulfide (PPS), etc.) generally used for a sliding bearing is used. Can be used.

  In this state, the capacitors 8a and 8b are configured by disposing the second electrode 114 so as to face the first electrode 102 with the non-conductive boundary layer 120 interposed therebetween. For example, in the example of FIG. 10A, the first electrode 102 connected to the AC power source 7 and the second electrode 114 arranged on the outer peripheral side of the electrode fixing plate 112 are arranged so as to face each other. As a result, the first coupling capacitor 8a is configured. Further, the second coupling capacitor 8b is formed by disposing the first electrode 102 connected to the GND and the second electrode 114 disposed on the inner peripheral side of the electrode fixing plate 112 so as to face each other. Is configured.

  Alternatively, in the example of FIG. 10B, the first electrode 102 connected to the AC power source 7 and the second electrode 114 disposed on one surface of the electrode fixing plate 112 are opposed to each other. The first coupling capacitor 8a is configured by being arranged. Further, the second coupling capacitor 8b is formed by disposing the first electrode 102 connected to the GND and the second electrode 114 disposed on the other surface of the electrode fixing plate 112 so as to face each other. Is configured.

  As shown in FIG. 10, the first coil 33a connected to the AC power source 7 is arranged in series with the first coupling capacitor 8a, and the second coil 33b connected to GND is the second coupling capacitor. 8b is arranged in series. These coils 33a and 33b constitute a series resonance circuit with the capacitors 8a and 8b to enable power transmission by series resonance.

(Function)
Next, the operation of the power supply system 1 configured as described above will be described. When the series resonance condition in the series resonance circuit configured by the capacitors 8a and 8b, the coils 33a and 33b, and the load 113 shown in FIG. 10 is satisfied, series resonance occurs, and the boundary layers 120 are disposed in contact with each other with the boundary layer 120 interposed therebetween. Electric power is supplied to the load 113 through the first electrode 102 and the second electrode 114.

(Effect of Embodiment 5)
As described above, according to the fifth embodiment, it is not necessary to directly contact the first electrode 102 disposed on the fixed body 100 and the second electrode 114 disposed on the rotating body 110. There is no need to consider management or electrode wear, and the reliability of power supply can be easily increased.

[Embodiment 6]
Next, a sixth embodiment will be described. In this form, the rotating body side electrode is directly provided on the shaft 2. The configuration of the sixth embodiment is substantially the same as the configuration of the fifth embodiment unless otherwise specified, and the configuration substantially the same as that of the first embodiment is the same as that used in the first embodiment. The code | symbol and / or name are attached | subjected as needed, and the description is abbreviate | omitted.

(Constitution)
FIG. 10 is a cross-sectional view of the power supply system 1 according to the sixth embodiment. In the power supply system 1 according to the sixth embodiment, the shaft 111 is provided with second electrodes 114a and 114b and a load 113. The second electrode 114a is an electrode formed integrally with a shaft 111 made of a conductor, and is arranged so that the first electrode 102 faces the second electrode 114a with a boundary layer 120 therebetween. As a result, the capacitor 8a is configured. The second electrode 114b is formed in a cylindrical shape along the peripheral surface of the shaft 111, and the outer surface thereof is substantially flush with the peripheral surface of the portion other than the second electrode 114 in the shaft 111. Are arranged as follows. The capacitor 8b is configured by disposing the first electrode 102 so as to face the second electrode 114b with the boundary layer 120 interposed therebetween. A cylindrical insulating layer 115 surrounding the second electrode 114b is provided around the second electrode 114b, and the second electrode 114a and the second electrode 114b are insulated from each other by the insulating layer 115. ing. In the example of FIG. 10, the second electrode 114a is configured by the shaft 111 itself. However, the second electrode 114a is formed with the same structure as the second electrode 114b at a position facing the first electrode 102 configuring the capacitor 8a. Two electrodes 114a may be arranged.

(Effect of Embodiment 6)
As described above, according to the sixth embodiment, in addition to the same effects as those of the fifth embodiment, the electrode fixing plate 112 shown in the fifth embodiment is not necessary, so that the structure can be further simplified and the power supply can be performed. Reliability can be further enhanced.

[Embodiment 7]
Next, a seventh embodiment will be described. In this form, only one set of coupling capacitors is provided. The configuration of the seventh embodiment is substantially the same as the configuration of the first embodiment except where otherwise specified. The configuration substantially the same as that of the first embodiment is the same as that used in the first embodiment. The code | symbol and / or name are attached | subjected as needed, and the description is abbreviate | omitted.

(Constitution)
In the first to sixth embodiments described above, the first bearing electrode 32a (in the fifth and sixth embodiments, the AC power supply 7) is sandwiched between the non-conductive boundary layer 4 (the boundary layer 120 in the fifth and sixth embodiments). The first coupling electrode 8a is configured by arranging the first shaft electrode 20 (the second electrode 114 in the fifth and sixth embodiments) so as to face the first electrode 102 connected to the first electrode 102). The second shaft electrode 21 (implemented) so as to face the second bearing electrode 32b (the first electrode 102 connected to GND in the fifth and sixth embodiments) across the non-conductive boundary layers 4 and 120. In the fifth and sixth embodiments, the second coupling capacitor 8b is configured by disposing the second electrode 114). However, the plurality of capacitors 8a and 8b are not necessarily required, and the power supply system 1 according to the seventh embodiment has only one coupling capacitor.

  For example, the power supply system 1 according to the seventh embodiment includes only the first coupling capacitor 8a configured by the first bearing electrode 32a and the first shaft electrode 20. In this case, the first shaft electrode 20 is connected to one electrode of the load 6, and the GND is connected to the other electrode using a known means (for example, a brush or the like). As a result, a closed circuit is formed, and power is supplied from the AC power supply 7 to the load 6 via the first coupling capacitor 8a.

(Effect of Embodiment 7)
As described above, according to the seventh embodiment, since it is not necessary to directly contact the bearing electrodes 32a and 32b and the shaft electrodes 20 and 21, it is not necessary to consider the contact pressure management between the electrodes, electrode wear, and the like. In addition, the reliability of power supply can be easily increased.

[III] Modifications to Each Embodiment While each embodiment according to the present invention has been described above, the specific configuration and means of the present invention are the same as the technical idea of each invention described in the claims. Modifications and improvements can be arbitrarily made within the range. Hereinafter, such a modification will be described.

(About problems to be solved and effects of the invention)
First, the problems to be solved by the invention and the effects of the invention are not limited to the above contents, and may vary depending on the implementation environment of the invention and the details of the configuration, and only a part of the problems described above. May be solved, or only some of the effects described above may be achieved. Furthermore, according to the present invention, problems not described above may be solved or effects not described above may be achieved.

(About application target of power supply system)
In each of the above-described embodiments, the case where power is supplied from a fixed power source to a rotating shaft has been described as an example. However, the power supply system 1 is also used when power is supplied from a rotating shaft to a bearing. Can be applied. Further, the present invention can be applied to any case where the bearing is fixedly installed and the shaft rotates, or where the shaft is fixedly installed and the bearing rotates. Furthermore, the present invention can be applied to either a case where a power source is provided inside the bearing or the shaft or a case where power is supplied from a power source outside the bearing or the shaft. Further, the present invention can be applied to either the case where the relative position between the shaft and the bearing is fixed in the axial direction, or the case where the position between the shaft and the bearing varies relatively in the axial direction.

(About bearings)
In the first to fourth embodiments described above, the case where the bearing is constituted by the first bearing 3a and the second bearing 3b has been described as an example. However, the first bearing 3a and the second bearing are described. 3b may be formed as an integral bearing, and the first bearing electrode 32a and the second bearing electrode 32b may be insulated from each other on the inner peripheral surface of the bearing.

(About coils)
In the first, third, fifth, and sixth embodiments described above, the case where the first coil 33a and the second coil 33b are provided as an example has been described. However, the first coil 33a and the second coil 33b are described as examples. The two coils 33b may be integrated into one coil. In this case, the arrangement position of the integrated coil is arbitrary, and may be connected in series to either the first coupling capacitor 8a or the second coupling capacitor 8b. The shaft 2 (the shaft 111 in the fifth and sixth embodiments), The bearing 3 (the bearing 101 in the fifth and sixth embodiments) or the fixed body 100 may be used.

  The present invention supplies power to various loads, and in particular, can supply power to the rotating body 5 efficiently with a simple structure, and is useful for a highly reliable power supply system. .

DESCRIPTION OF SYMBOLS 1 Electric power supply system 2, 111 Axis 2a 1st axis | shaft 2b 2nd axis | shaft 3, 101 Bearing 3a 1st bearing 3b 2nd bearing 4, 120 Boundary layer 5, 110 Rotating body 6, 113 Load 7 AC power supply 8a 1st coupling capacitor 8b 2nd coupling capacitor 8c 3rd coupling capacitor 8d 4th coupling capacitor 9 communication part 9a coupling capacitor for communication 10 synchronization chain 11 motor 12 support bearing 13 nut 14 moving body 20 first Axis electrode 21 Second shaft electrode 22 Power line 30 Fixing base 31 Conductive fixing portion 32a First bearing electrode 32b Second bearing electrode 33a First coil 33b Second coil 40 First parallel resonance circuit 41 First Capacitor 42 Third coil 50 Second parallel resonant circuit 51 Second capacitor 52 Fourth coil 60 Third parallel resonant circuit 61 third capacitor 62 fifth coil 70 fourth parallel resonant circuit 71 fourth capacitor 72 sixth coil 100 fixed body 102 of the first electrode 112 electrode fixing plates 114 and 114a, 114b the second electrode 115 insulating layer

Claims (6)

A power supply system comprising a shaft and a bearing that supports the shaft across a boundary layer, and that supplies power to a predetermined load from an AC power source via the shaft and the bearing,
The bearing comprises a bearing electrode;
The shaft includes a shaft electrode that is disposed in a non-contact manner and opposed to the bearing electrode across the boundary layer,
A coupling capacitor is configured by arranging the shaft electrode so as to face the bearing electrode,
The AC power supply is
Power is transmitted to the load via the coupling capacitor;
Power supply system. The bearing is
Comprising the first and second bearing electrodes to which power is supplied;
The axis is
Comprising the first axial electrode and the second axial electrode;
The first shaft electrode is disposed so as to face the first bearing electrode, thereby forming the first coupling capacitor, and the second shaft so as to face the second bearing electrode. The second coupling capacitor is configured by arranging the shaft electrode,
The AC power supply is
Power is transmitted to the load through the first and second coupling capacitors;
The power supply system according to claim 1. The shaft or the bearing is
A first coil connected in series to the first coupling capacitor; and a second coil connected in series to a second coupling capacitor;
The AC power supply is
The load is passed through the first coupling capacitor and the second coupling capacitor under the condition that series resonance is generated in the first coupling capacitor and the first coil and the second coupling capacitor and the second coil. Power transmission to the
The power supply system according to claim 2. The bearing is
A plurality of the first bearing electrodes;
The axis is
A plurality of the first axial electrodes;
The plurality of first coupling capacitors are configured by disposing the plurality of first shaft electrodes so as to face the plurality of first bearing electrodes,
The shaft or the bearing is
A plurality of the first coils connected in series for each of the plurality of first coupling capacitors;
The AC power supply is
The plurality of first coupling capacitors and the second coupling under a condition for generating a series resonance in the plurality of first coupling capacitors and the plurality of first coils and the second coupling capacitor and the second coil. Transmitting power to the plurality of loads via a capacitor;
The power supply system according to claim 3. The axial electrode is
Formed into a male thread shape,
The bearing electrode is
Formed into a female screw shape screwed into the male screw shape of the shaft electrode,
The power supply system according to any one of claims 1 to 4. The axis is
A first capacitor and a third coil connected in parallel with each other between the first shaft electrode and the second shaft electrode;
The AC power supply is
Power transmission to the load is performed via the first coupling capacitor and the second coupling capacitor under the condition of causing parallel resonance in the first capacitor and the third coil.
The power supply system according to claim 2.

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