WO2016009814A1

WO2016009814A1 - Contactless power transmission apparatus and rotating electric machine

Info

Publication number: WO2016009814A1
Application number: PCT/JP2015/068490
Authority: WO
Inventors: 高三　正己; 山本　幸宏; 航大鈴木
Original assignee: 株式会社豊田自動織機
Priority date: 2014-07-17
Filing date: 2015-06-26
Publication date: 2016-01-21
Also published as: JP2016025697A

Abstract

This contactless power transmission apparatus is provided with a rotary electrode and a stationary electrode. The rotary electrode is fixed to a rotatable rotary body and is shaped like a flat ring protruding in the radial direction from an outer circumferential surface of the rotary body. The stationary electrode has an insertion through-hole through which the rotary body is inserted and is shaped like a flat ring that is retained so as not to rotate along with the rotation of the rotary body. The rotary electrode and the stationary electrode are disposed opposite each other in the axial direction of the rotary body to form a coupling capacitor. Power is transmitted via the coupling capacitor in a contactless manner.

Description

Non-contact power transmission device and rotating electric machine

The present invention relates to a non-contact power transmission device and a rotating electric machine.

A non-contact power transmission device that performs non-contact power transmission is known. The non-contact power transmission device includes, for example, a cylindrical rotating electrode that rotates with the rotation of the rotating body, and a cylindrical holding electrode that is held so as not to rotate with the rotation of the rotating body. For example, see Patent Document 1. In such a non-contact power transmission device, power transmission is performed in a non-contact manner via a coupling capacitor configured by disposing the rotating electrode and the holding electrode so as to face each other in the radial direction.

JP 2011-19293 A

In a configuration in which contactless power transmission is performed via a coupling capacitor, an improvement in the capacitance of the coupling capacitor may be required in order to perform contactless power transmission with a relatively large power value. In addition, when the rotating electrode and the holding electrode are cylindrical and are configured to face each other in the radial direction as described above, since both the electrodes are curved, the distance between the electrodes is locally determined depending on the circumferential position. There is a risk of variation. In this case, concentration of electric charges may occur, and trouble may occur in non-contact power transmission. However, it is not preferable from the viewpoint of cost and the like to form the rotating electrode and the holding electrode with high accuracy in order to suppress the local variation in the inter-electrode distance. From the above, there is still room for improvement in the configuration for performing non-contact power transmission via the coupling capacitor.

An object of the present invention is to provide a non-contact power transmission device capable of suitably performing non-contact power transmission via a coupling capacitor, and a rotating electrical machine including the non-contact power transmission device.

The first mode for achieving the above object provides a non-contact power transmission apparatus. The non-contact power transmission device is fixed to a rotatable rotating body, and has a flat plate ring-shaped rotating electrode protruding in a radial direction from an outer peripheral surface of the rotating body, and an insertion hole through which the rotating body is inserted, A flat ring-shaped holding electrode that is held so as not to rotate with the rotation of the rotating body, and the rotating electrode and the holding electrode are coupled by being arranged opposite to each other in the axial direction of the rotating body. A capacitor is formed, and contactless power transmission is performed via the coupling capacitor.

A second mode for achieving the above object provides a rotating electric machine. The rotating electrical machine includes a rotor provided with a coil and the non-contact power transmission device according to the first aspect. The rotating electrode is connected to the coil.

The perspective view which mainly shows the rotor of a rotary electric machine. The cross-sectional perspective view which mainly shows the rotor of a rotary electric machine. Sectional drawing which shows a non-contact electric power transmission apparatus typically. The exploded perspective view of a u phase unit. The circuit diagram of an inverter and a rotary electric machine. The schematic diagram which shows the rotary electric machine of another example. Sectional drawing which shows typically the non-contact electric power transmission apparatus of another example. Furthermore, the schematic diagram which shows another rotary electric machine. FIG. 9 is a sectional view taken along line 9-9 in FIG.

Hereinafter, an embodiment of a rotating electrical machine to which a non-contact power transmission device is applied will be described. Incidentally, the rotating electrical machine is mounted on a vehicle having a power storage device such as a battery, and is used to drive the vehicle using the power of the power storage device. The rotating electrical machine generates regenerative power when the vehicle is decelerated, for example. The regenerative power is used for applications such as charging of power storage devices.

For convenience of illustration, FIG. 1 and FIG. 2 show only a part of the u-phase coil 24u out of the three coils 24u to 24w. Further, in FIG. 1, only a part of the stator 14 is shown by a two-dot chain line.

First, an outline of the rotating electrical machine 11 will be described. As shown in FIG. 1, the rotating electrical machine 11 includes a rotating shaft 12, a rotor 13 to which the rotating shaft 12 is fixed and rotating integrally with the rotating shaft 12, and a stator 14 disposed outside the rotor 13. Yes. The rotating electrical machine 11 is a so-called three-phase AC motor.

The rotating electrical machine 11 includes a housing (not shown) in which a rotating shaft 12, a rotor 13, and a stator 14 are accommodated, and a bearing that supports the rotating shaft 12 is accommodated in the housing. The stator 14 and the housing are thermally coupled. For this reason, the stator 14 can be cooled by the housing.

The rotor 13 has a bottomed cylindrical shape as a whole. The rotor 13 includes a main body portion 21 and a core 22 fixed to the outer peripheral surface of the main body portion 21. The main body 21 has an insertion hole 21a through which the rotary shaft 12 is inserted at the bottom. The core 22 has a substantially cylindrical shape as a whole. A plurality of slots 23 are juxtaposed in the circumferential direction of the core 22 on the outer peripheral surface of the core 22. Each slot 23 extends in the axial direction of the rotor 13. In the plurality of slots 23, a plurality of coils 24u to 24w are wound.

The stator 14 is a permanent magnet, for example. The stator 14 has a curved shape and is disposed at a position facing the outer peripheral surface of the core 22 of the rotor 13. That is, the rotating electrical machine 11 is of a type in which a plurality of coils 24 u to 24 w are provided on the rotor 13 disposed inside the stator 14.

As shown in FIG. 2, the rotating electrical machine 11 includes a rotating body 30 that rotates as the rotor 13 rotates. The rotating body 30 is made of an insulating material (for example, resin). The rotating body 30 is provided inside the main body 21 of the rotor 13. The rotating body 30 has a cylindrical shape having the same inner diameter as the rotating shaft 12, and the axial direction of the rotating body 30 coincides with the axial direction of the rotor 13. The rotating shaft 12 is inserted through the rotating body 30 so as to rotate integrally with the rotating body 30. In this case, the axial direction of the rotating shaft 12, the axial direction of the rotating body 30, and the axial direction of the rotor 13 are the same. The rotating body 30 and the rotor 13 have a common axis O (FIG. 3). That is, the rotating shaft 12, the rotating body 30, and the rotor 13 are arranged concentrically around the axis O.

The rotating body 30 is composed of an enlarged diameter portion 31 disposed near the bottom of the main body portion 21 and a reduced diameter portion 32 having an outer diameter smaller than that of the enlarged diameter portion 31. The enlarged diameter portion 31 is fixed to the bottom portion of the main body portion 21 of the rotor 13. Thereby, the rotating body 30 rotates as the rotor 13 rotates.

The rotating electrical machine 11 is attached to the reduced diameter portion 32 of the rotating body 30, and includes a non-contact power transmission device 50 that performs non-contact power transmission to the plurality of coils 24u to 24w.

The rotating electrical machine 11 has a configuration for electrically connecting the non-contact power transmission device 50 and the coils 24u to 24w. Before describing the specific configuration of the non-contact power transmission device 50, the connection configuration of the non-contact power transmission device 50 and the coils 24u to 24w will be briefly described.

As shown in FIGS. 1 and 2, the rotating electrical machine 11 holds a u-phase bus bar 42u electrically connected to a u-phase lead wire 41u drawn from the coil end of the u-phase coil 24u, and a u-phase bus bar 42u. And a bus bar holding portion 43. The bus bar holding portion 43 has an insulating property and is attached to the bottom portion of the main body portion 21 from the outside.

Further, as shown in FIG. 2, rod-shaped u-phase rotor wiring 44 u extending in the axial direction of the rotating body 30 is embedded in the rotating body 30. The u-phase rotor wiring 44 u passes through the bottom portion of the main body 21 and the bus bar holding portion 43, and a part of the u-phase rotor wiring 44 u protrudes from the bus bar holding portion 43. The u-phase bus bar 42u is fixed (fastened in detail) to the bus bar holding portion 43 in a state where the u-phase rotor wiring 44u and the u-phase lead wire 41u are connected.

Similar to the configuration relating to the u-phase, the rotating electrical machine 11 includes a v-phase lead wire (not shown) drawn from the coil end of the v-phase coil 24v and a v-phase rotor wiring (not shown) embedded in the rotating body 30. V-phase bus bar 42v. Then, the rotating electrical machine 11 connects the w-phase lead wire (not shown) drawn from the coil end of the w-phase coil 24 w and the w-phase rotor wiring (not shown) embedded in the rotating body 30. 42w. The bus bar holding unit 43 holds the

bus bars

42u, 42v, and 42w.

Next, a specific configuration of the non-contact power transmission device 50 will be described.
The non-contact power transmission device 50 includes a u-phase unit 50u corresponding to the u-phase coil 24u, a v-phase unit 50v corresponding to the v-phase coil 24v, and a w-phase unit 50w corresponding to the w-phase coil 24w. Each of the phase units 50u to 50w is attached to a reduced diameter portion 32 of the rotating body 30 disposed inside the rotor 13. The phase units 50u to 50w are arranged at a predetermined interval in the axial direction of the rotating body 30. Since each of these phase units 50u to 50w has basically the same configuration, the u-phase unit 50u will be described in detail below with reference to FIGS. 3 and 4, and the details of the v-phase unit 50v and the w-phase unit 50w will be described in detail. Description is omitted. In FIG. 4, for convenience of illustration, the rotating body 30 is indicated by a two-dot chain line, and the illustration of the holding member 81 is omitted.

As shown in FIGS. 3 and 4, the u-phase unit 50u includes a plate-ring-shaped u-phase rotating electrode 51u protruding in the radial direction from the outer peripheral surface of the reduced diameter portion 32 of the rotating body 30. The u-phase rotating electrode 51 u is fixed to the rotating body 30 and rotates as the rotating body 30 rotates.

The u-phase rotating electrode 51u is connected to the u-phase rotor wiring 44u embedded in the rotating body 30. Thereby, the u-phase rotating electrode 51u is connected to the u-phase coil 24u via the u-phase rotor wiring 44u, the u-phase bus bar 42u, and the u-phase lead wire 41u.

The u-phase unit 50u includes a plate-ring-shaped u-phase holding electrode 52u that is held so as not to rotate with the rotation of the rotating body 30. The u-phase holding electrode 52u has an insertion hole 52uc through which the rotating body 30 is inserted. The insertion hole 52uc is formed to be slightly larger than the reduced diameter portion 32 of the rotating body 30. The u-phase holding electrode 52u is held such that the inner peripheral surface thereof does not contact the reduced diameter portion 32 of the rotating body 30. The u-phase rotating electrode 51 u and the u-phase holding electrode 52 u are disposed on the same axis and opposed to each other in the axial direction of the rotating body 30. Thereby, the u-phase coupling capacitor Cu is configured.

The u-phase rotating electrode 51u and the u-phase holding electrode 52u are not always in direct contact with each other during the operation of the rotating electrical machine. As described above, the u-phase rotating electrode 51u and the u-phase holding electrode 52u are not in mechanical contact with each other.

In the present embodiment, the u-phase rotating electrode 51u and the u-phase holding electrode 52u are circular rings as viewed from the axial direction of the rotating body 30, and the outer diameters of both are set to be the same.
As shown in FIG. 3, the u-phase rotating electrode 51u has a rotation-facing surface 51ua that faces the u-phase holding electrode 52u. The rotation facing surface 51 ua is a flat surface orthogonal to the axial direction of the rotating body 30. That is, the rotation opposing surface 51ua is a flat surface extending in the radial direction of the rotating body 30. A first rotating dielectric layer 61 (rotating dielectric portion) having a dielectric constant higher than that of air is provided on the rotation facing surface 51ua. Similarly, a second rotating dielectric layer 62 having a dielectric constant higher than that of air is provided on a surface 51ub of the u-phase rotating electrode 51u opposite to the rotation facing surface 51ua. The first rotating dielectric layer 61 and the second rotating dielectric layer 62 have a plate ring shape like the u-phase rotating electrode 51u. The u-phase rotating electrode 51 u is sandwiched between the first rotating dielectric layer 61 and the second rotating dielectric layer 62 from the axial direction of the rotating body 30. The u-phase rotating electrode 51u, the first rotating dielectric layer 61, and the second rotating dielectric layer 62 are unitized by a process such as sintering.

Similarly, the u-phase holding electrode 52u has a holding facing surface 52ua that faces the u-phase rotating electrode 51u. The holding facing surface 52 ua is a flat surface that is orthogonal to the axial direction of the rotating body 30. That is, the holding facing surface 52 ua is a flat surface extending in the radial direction of the rotating body 30. The holding facing surface 52ua is provided with a first holding dielectric layer 71 (holding dielectric portion) having a dielectric constant higher than that of air. A second holding dielectric layer 72 having a dielectric constant higher than that of air is provided on the surface 52ub of the u-phase holding electrode 52u opposite to the holding facing surface 52ua. The u-phase holding electrode 52u, the first holding dielectric layer 71, and the second holding dielectric layer 72 are unitized by a process such as sintering.

The constituent material of each of the

dielectric layers

61, 62, 71, 72 is arbitrary as long as it has a dielectric constant higher than that of air. For example, it is a dielectric ceramic such as barium titanate. The surface of the first rotating dielectric layer 61 and the surface of the first holding dielectric layer 71 are flat surfaces orthogonal to the axial direction of the rotating body 30. That is, the surface of the first rotating dielectric layer 61 and the surface of the first holding dielectric layer 71 are flat surfaces extending in the radial direction of the rotating body 30.

Further, the first rotating dielectric layer 61 and the first holding dielectric layer 71 are configured to be more slippery than the u-phase rotating electrode 51u and the u-phase holding electrode 52u. Specifically, the friction coefficient of the dielectric ceramics that is the constituent material of the first rotating dielectric layer 61 and the first holding dielectric layer 71 is smaller than the friction coefficient of the u-phase rotating electrode 51u and the u-phase holding electrode 52u.

As shown in FIG. 3, a fluid lubricating oil 80 is disposed as a lubricant between the first rotating dielectric layer 61 and the first holding dielectric layer 71. That is, the u-phase coupling capacitor Cu includes the u-phase rotating electrode 51u and the u-phase holding electrode 52u that are opposed to each other in the axial direction of the rotating body 30, the first rotating dielectric layer 61, the lubricating oil 80, and the first phase interposed therebetween. And a holding dielectric layer 71. The lubricating oil 80 is made of a material having a dielectric constant higher than that of air. However, in this embodiment, the dielectric constant of the lubricating oil 80 is lower than the dielectric constants of both the

dielectric layers

61 and 71.

The capacitance of the u-phase coupling capacitor Cu configured as described above is that the dielectric constants of both the

dielectric layers

61 and 71 and the lubricating oil 80 and the opposing direction of the u-phase rotating electrode 51u and the u-phase holding electrode 52u (that is, It depends on conditions such as the inter-electrode distance dx, which is a separation distance in the axial direction of the rotating body 30, and the facing area between the u-phase rotating electrode 51u and the u-phase holding electrode 52u.

The facing area is an area of an overlapping region of the rotating facing surface 51ua and the holding facing surface 52ua as viewed from the axial direction of the rotating body 30, and depends on the areas of the rotating facing surface 51ua and the holding facing surface 52ua. Strictly speaking, in the present embodiment, in order to avoid sliding with the rotating body 30, the insertion hole 52uc is formed to be slightly larger than the rotating body 30, and the outer diameter is the same. The area matches the area of the holding facing surface 52ua.

A configuration related to holding of the u-phase holding electrode 52u will be described. As shown in FIGS. 2 and 3, the non-contact power transmission device 50 includes a holding member 81 that is used to hold the u-phase holding electrode 52 u. The holding member 81 is made of an insulating material such as resin. The holding member 81 has, for example, a cylindrical shape having an inner diameter larger than the outer diameter of the u-phase rotating electrode 51u and the u-phase holding electrode 52u and an outer diameter smaller than the inner diameter of the main body portion 21. The holding member 81 covers each of the phase units 50u to 50w from the outside in the radial direction of the rotating body 30. One end of the holding member 81 in the axial direction is fixed to the housing. For this reason, the holding member 81 does not rotate with the rotation of the rotating body 30.

As illustrated in FIGS. 3 and 4, the u-phase unit 50 u of the non-contact power transmission device 50 includes a u-phase holding unit 82 u that holds the u-phase holding electrode 52 u while being movable in the axial direction of the rotating body 30. A plurality (for example, four) are provided. Each of the plurality of u-phase holding portions 82u is made of an elastic member such as a spring or elastic rubber (rubber). The plurality of u-phase holding portions 82u are arranged apart from each other in the circumferential direction of the rotating body 30. One end of each u-phase holding part 82u is connected to a unit body composed of the u-phase holding electrode 52u, the first holding dielectric layer 71, and the second holding dielectric layer 72, and the other end of each u-phase holding part 82u. Is connected to the inner peripheral surface of the holding member 81. The plurality of u-phase holding portions 82u allow the unit body to move in the axial direction of the rotating body 30 that is the opposing direction of the u-phase rotating electrode 51u and the u-phase holding electrode 52u, while rotating the unit body (that is, (Movement of the rotating body 30 in the circumferential direction) is regulated. Thus, the u-phase holding electrode 52u is held so as not to rotate with the rotation of the rotating body 30 while being movable in the axial direction of the rotating body 30.

As shown in FIGS. 3 and 4, the u-phase unit 50 u of the non-contact power transmission device 50 serves as a pressing unit that presses the u-phase holding electrode 52 u toward the u-phase rotating electrode 51 u from the axial direction of the rotating body 30. The u-phase disc spring 83u is provided. A u-phase wall portion 84 u that protrudes radially inward from the inner peripheral surface is provided on the inner peripheral surface of the holding member 81. The u-phase wall portion 84u has a plate ring shape having an inner diameter that is slightly larger than that of the rotating body 30. The u-phase wall portion 84u is disposed on the opposite side of the u-phase holding electrode 52u from the u-phase rotating electrode 51u side, and is fixed to the holding member 81 at that position. The u-phase disc spring 83u is disposed between the u-phase wall portion 84u and the u-phase holding electrode 52u. In this case, the u-phase holding electrode 52u is pressed from the axial direction of the rotating body 30 toward the u-phase rotating electrode 51u by the biasing force of the u-phase disc spring 83u.

The axial direction of the rotating body 30, which is the opposing direction of the u-phase rotating electrode 51u and the u-phase holding electrode 52u, is defined as the thickness direction. In this case, as shown in FIG. 3, the thickness of the first rotating dielectric layer 61 and the thickness of the first holding dielectric layer 71 are set to be the same (hereinafter referred to as dielectric layer thickness d1). The thickness d2 of the lubricating oil 80 when the u-phase rotating electrode 51u is rotating in a state where the u-phase holding electrode 52u is pressed by the u-phase disc spring 83u is thinner than the dielectric layer thickness d1.

As shown in FIG. 3, the non-contact power transmission device 50 includes a u-phase stator wiring 85u connected to the u-phase holding electrode 52u. A part of the u-phase stator wiring 85u is embedded in the holding member 81 and connected to an inverter 100 (see FIG. 5) as a drive circuit for driving the rotating electrical machine 11. Another part of the u-phase stator wiring 85u is connected in a relaxed state between the portion embedded in the holding member 81 and the u-phase holding electrode 52u. Thereby, the u-phase stator wiring 85u is configured such that the u-phase holding electrode 52u follows the movement of the rotating body 30 in the axial direction.

As shown in FIG. 2, similarly to the u-phase unit 50u, the v-phase unit 50v has a v-phase coupling capacitor Cv composed of components such as a v-phase rotating electrode 51v and a v-phase holding electrode 52v. The v-phase rotating electrode 51v is connected to the v-phase coil 24v via the v-phase rotor wiring and the v-phase bus bar 42v. The v-phase holding electrode 52v is connected to the inverter 100 via a v-phase stator wiring (not shown) partially embedded in the holding member 81.

Similarly, the w-phase unit 50w has a w-phase coupling capacitor Cw composed of components such as a w-phase rotating electrode 51w and a w-phase holding electrode 52w. The w-phase rotating electrode 51w is connected to the w-phase coil 24w via the w-phase rotor wiring and the w-phase bus bar 42w. The w-phase holding electrode 52 w is connected to the inverter 100 via w-phase stator wiring (not shown) partially embedded in the holding member 81.

Here, the capacitance of the coupling capacitors Cu to Cw is one parameter that defines the power value at which non-contact power transmission is performed. Specifically, as the capacitances of the coupling capacitors Cu to Cw are larger, the value of electric power transmitted in a non-contact manner can be increased. In this embodiment, since the coupling capacitors Cu to Cw have the same shape, the capacitances of the coupling capacitors Cu to Cw are the same.

Further, the non-contact power transmission device 50 includes a v-phase holding unit, a v-phase disc spring 83v and a v-phase wall portion 84v, and a w-phase holding unit, a w-phase disc spring 83w and a w-phase wall portion 84w. These configurations are the same as the corresponding configurations in the u phase.

A specific method for manufacturing the non-contact power transmission device 50 of the present embodiment is arbitrary. For example, there are components such as holding electrodes 52u to 52w having a dielectric layer formed on both surfaces, holding portions, and disc springs 83u to 83w. The unit body of the attached holding member 81 is divided along the axial direction. Then, with respect to the rotating body 30 to which the rotating electrodes 51u to 51w having dielectric layers formed on both surfaces are fixed, the divided parts of the unit body are perpendicular to the axial direction of the rotating body 30 (for example, the vertical direction, ie, the radial direction). ), And in that state, joining is performed by a joining method such as sintering or welding, and then the rotating body 30 is fixed to the main body 21.

Next, the electrical configuration of the rotary electric machine 11 and the inverter 100 will be described in detail.
As shown in FIG. 5, inverter 100 corresponds to u-phase switching elements Qu1 and Qu2 corresponding to u-phase coil 24u, v-phase switching elements Qv1 and Qv2 corresponding to v-phase coil 24v, and w-phase coil 24w. w-phase switching elements Qw1 and Qw2 are provided. Each of the switching elements Qu1, Qu2, Qv1, Qv2, Qw1, and Qw2 (hereinafter simply referred to as switching elements Qu1 to Qw2) is composed of, for example, an IGBT.

The u-phase switching elements Qu1 and Qu2 are connected to each other in series via a connection line, and the connection line is connected to the u-phase holding electrode 52u. And direct-current power is input from the battery B mounted in the vehicle with respect to the series connection body of each u-phase switching element Qu1, Qu2. Since the other switching elements Qv1, Qv2, Qw1, and Qw2 have the same connection mode as the u-phase switching elements Qu1 and Qu2 except that the corresponding holding electrodes are different, detailed description thereof is omitted. Each of the coils 24u to 24w is, for example, delta-connected.

The inverter 100 includes a control circuit 101 that controls the switching operation of the switching elements Qu1 to Qw2. The control circuit 101 converts the DC power into AC power by periodically turning on / off the switching elements Qu1 to Qw2, and supplies the AC power to the holding electrodes 52u to 52w. The AC power is supplied in a non-contact manner to the coils 24u to 24w via the coupling capacitors Cu to Cw. Thereby, the rotor 13 rotates.

The plurality of switching elements Qu1 to Qw2 have body diodes (parasitic diodes) Du1 to Dw2, respectively. The regenerative power generated in each of the coils 24u to 24w is rectified by the body diodes Du1 to Dw2 and input to the battery B. Thereby, the battery B is charged. That is, the inverter 100 is a power conversion unit capable of bidirectional conversion between DC power and AC power.

For example, when the first u-phase switching element Qu1 is in the ON state, the second u-phase switching element Qu2 is in the OFF state, the first v-phase switching element Qv1 is in the OFF state, and the second v-phase switching element Qv2 is in the ON state. Power transmission is performed through a path of u-phase coupling capacitor Cu → u-phase coil 24u → v-phase coupling capacitor Cv. In this case, a series resonance circuit is configured by the u-phase coupling capacitor Cu, the u-phase coil 24u, and the v-phase coupling capacitor Cv. That is, the u-phase coil 24u constitutes the series resonance circuit in cooperation with the u-phase coupling capacitor Cu and the v-phase coupling capacitor Cv.

In a switching mode different from the switching mode described above, a series resonance circuit is configured by two coupling capacitors among the coupling capacitors Cu to Cw and one coil among the coils 24u to 24w.

The inductances of the coils 24u to 24w are the same. As already described, the capacitances of the coupling capacitors Cu to Cw are the same. Therefore, the resonance frequency is the same regardless of which series resonance circuit is configured.

The control circuit 101 performs ON / OFF control of the switching elements Qu1 to Qw2 in accordance with the resonance frequency. That is, the control circuit 101 performs ON / OFF control of the switching elements Qu1 to Qw2 so that AC power having the same frequency as the resonance frequency is output. The control circuit 101 variably controls the rotational speed of the rotor 13 by variably controlling the ON / OFF duty ratios of the switching elements Qu1 to Qw2.

Next, the operation of this embodiment will be described.
The AC power output from the inverter 100 is supplied to the coils 24u to 24w in a non-contact manner via the coupling capacitors Cu to Cw. Thereby, the rotor 13 and the rotary body 30 rotate. In this case, an oil film pressure is generated in the lubricating oil 80 by the rotation of the u-phase rotating electrode 51u in a state where the u-phase holding electrode 52u is pressed toward the u-phase rotating electrode 51u. For this reason, the balance of force is maintained and the thickness d2 of the lubricating oil 80 is kept constant.

According to the embodiment described above in detail, the following effects are obtained. For convenience of explanation, some effects will be described only for the u phase, but the same effects can be achieved for the v phase and the w phase.
(1) The non-contact power transmission device 50 is fixed to a rotatable rotating body 30, and a flat plate ring-shaped u-phase rotating electrode 51 u protruding radially from the outer peripheral surface of the rotating body 30 and the rotating body 30 are inserted. And a flat plate ring-shaped u-phase holding electrode 52u that is held so as not to rotate with the rotation of the rotating body 30. The u-phase rotating electrode 51 u and the u-phase holding electrode 52 u are disposed to face each other in the axial direction of the rotating body 30. The non-contact power transmission device 50 is configured to perform non-contact power transmission via a u-phase coupling capacitor Cu configured by a u-phase rotating electrode 51u and a u-phase holding electrode 52u. According to this configuration, the end faces in the axial direction (rotation facing surface 51 ua and holding facing surface 52 ua) of the plate-shaped u-phase rotating electrode 51 u and u phase holding electrode 52 u are opposed to each other in the axial direction of the rotating body 30. Therefore, the local variation in the interelectrode distance dx can be relatively easily suppressed as compared with the configuration in which the curved electrodes face each other in the radial direction.

More specifically, if the cylindrical rotating electrode and the holding electrode are opposed to each other in the radial direction, the rotating electrode and the holding electrode are curved so that the inter-electrode distance dx does not vary depending on the position in the circumferential direction. There is a need to. Such curve formation tends to be less accurate than the formation of a flat surface. On the other hand, in this embodiment, since both rotation opposing surface 51ua and holding | maintenance opposing surface 52ua should just be flat surfaces, compared with the structure formed curvedly, desired precision can be obtained easily. Thereby, the local dispersion | variation in the distance dx between electrodes can be suppressed comparatively easily, and the concentration of an electric charge can be suppressed suitably through it.

In particular, when the rotating electrode and the holding electrode are cylindrical and are configured to face each other in the radial direction, the capacitance of the coupling capacitor depends on the axial length of the rotating electrode and the holding electrode. On the other hand, when the u-phase rotating electrode 51u and the u-phase holding electrode 52u are plate ring shapes, the capacitance of the u-phase coupling capacitor Cu depends on the areas of the rotation facing surface 51ua and the holding facing surface 52ua. The area depends on the square of the radius of the u-phase rotating electrode 51u and the u-phase holding electrode 52u. For this reason, by increasing the outer diameters of the u-phase rotating electrode 51u and the u-phase holding electrode 52u, the capacitance of the u-phase coupling capacitor Cu can be improved while suppressing an increase in the size of the rotating body 30 in the axial direction. Through this, non-contact power transmission with a larger power value becomes possible.

(2) A first rotating dielectric layer 61 serving as a dielectric portion having a dielectric constant higher than that of air is provided on the rotation facing surface 51ua of the u phase rotating electrode 51u facing the u phase holding electrode 52u. A first holding dielectric layer 71 as the dielectric portion is provided on the holding facing surface 52ua of the u-phase holding electrode 52u that faces the u-phase rotating electrode 51u. Thereby, since both

dielectric layers

61 and 71 are interposed between the u-phase rotating electrode 51u and the u-phase holding electrode 52u, the capacitance of the u-phase coupling capacitor Cu can be improved. Further, the contact between the u-phase rotating electrode 51u and the u-phase holding electrode 52u is regulated by the both

dielectric layers

61 and 71. Thereby, the insulation between the u-phase rotating electrode 51u and the u-phase holding electrode 52u can be improved.

In order to improve the capacitance of the u-phase coupling capacitor Cu, it is conceivable to reduce the inter-electrode distance dx. However, if the inter-electrode distance dx is reduced, dielectric breakdown tends to occur when a high voltage is applied.

On the other hand, in the present embodiment, by interposing both

dielectric layers

61 and 71 having a high dielectric constant between the u-phase rotating electrode 51u and the u-phase holding electrode 52u, the electrostatic property of the u-phase coupling capacitor Cu is obtained. The interelectrode distance dx can be increased while improving the capacity. Thereby, even when a high voltage is applied between the u-phase rotating electrode 51u and the u-phase holding electrode 52u, dielectric breakdown is unlikely to occur. Therefore, it is possible to improve the withstand voltage while improving the capacitance of the u-phase coupling capacitor Cu. In other words, a decrease in capacitance, which can be caused by increasing the interelectrode distance dx in order to improve the pressure resistance, is caused by a high dielectric constant between the u-phase rotating electrode 51u and the u-phase holding electrode 52u. It can be said that this is alleviated by arranging the two

dielectric layers

61 and 71.

(3) Lubricating oil 80 as a lubricant is provided between the u-phase rotating electrode 51u and the u-phase holding electrode 52u, specifically between both

dielectric layers

61 and 71. Thereby, the u-phase rotating electrode 51u is smoothly rotated. Therefore, the rotation of the u-phase rotating electrode 51u is inhibited due to the sliding between the first rotating dielectric layer 61 and the first holding dielectric layer 71, and the wear and noise due to the sliding are suppressed. Can do.

(4) The lubricating oil 80 is made of a material having a dielectric constant higher than that of air. As a result, the capacitance of the u-phase coupling capacitor Cu can be further improved.
(5) The non-contact power transmission device 50 holds the u-phase holding electrode 52u in a state in which the u-phase holding electrode 52u can move in the axial direction of the rotating body 30 and does not rotate as the rotating body 30 rotates. 82u and a u-phase disc spring 83u as a pressing portion that presses the u-phase holding electrode 52u from the axial direction of the rotating body 30 toward the u-phase rotating electrode 51u. According to such a configuration, an oil film pressure is generated in the lubricating oil 80 when the u-phase rotating electrode 51u rotates in a state where the u-phase holding electrode 52u is pressed toward the u-phase rotating electrode 51u. Thereby, a thin layer of the lubricating oil 80 exists stably between the both

dielectric layers

61 and 71. Therefore, contact between both

dielectric layers

61 and 71 can be suppressed.

Further, according to the present embodiment, by using the oil film pressure, the thickness d2 of the lubricating oil 80 for suppressing the contact between the two

dielectric layers

61 and 71 can be reduced, and accordingly, the lubricating oil is correspondingly increased. The dielectric layer thickness d1, which is the thickness of both

dielectric layers

61 and 71 having a dielectric constant higher than 80, can be increased, and the inter-electrode distance dx can be decreased. As a result, the capacitance of the u-phase coupling capacitor Cu can be improved.

(6) In the configuration in which the surfaces of both

dielectric layers

61 and 71 are opposed to each other, the distance between both

dielectric layers

61 and 71 is locally based on the surface irregularities and minute curvature of both

dielectric layers

61 and 71. Can vary. In this case, there is a concern about charge concentration. In particular, when the thickness d2 of the lubricating oil 80, which is the distance between the two

dielectric layers

61 and 71, is reduced, the concentration of the charges tends to become remarkable.

In contrast, in the present embodiment, the surface of the first rotating dielectric layer 61 and the surface of the first holding dielectric layer 71 are flat surfaces orthogonal to the axial direction of the rotating body 30. Such a flat surface can be formed with relatively high accuracy as compared with a curved surface. Thereby, concentration of the charge can be suppressed.

(7) The friction coefficients of both

dielectric layers

61 and 71 are smaller than the friction coefficients of the u-phase rotating electrode 51u and the u-phase holding electrode 52u. As a result, even if both

dielectric layers

61 and 71 slide due to some factor, compared to the configuration in which the u-phase rotating electrode 51u and the u-phase holding electrode 52u slide, Wear and noise can be suppressed.

(8) The rotating electrical machine 11 includes a rotor 13 provided with three coils 24u to 24w and a non-contact power transmission device 50 having three phase units 50u to 50w. The rotating electrodes 51u to 51w of the three phase units 50u to 50w are connected to the three coils 24u to 24w. According to such a configuration, electric power can be transmitted to each of the coils 24u to 24w in a non-contact manner without using a slip ring or the like.

It is also possible to adopt an electromagnetic induction method or a magnetic field resonance method as a method for performing non-contact power transmission. However, in the above two methods, it is essential to form a magnetic field by the primary side coil and the secondary side coil. As a result, the magnetic field and the magnetic field between the rotor 13 and the stator 14 may interfere with each other, which may hinder the rotation of the rotor 13.

On the other hand, in the present embodiment, non-contact power transmission using an electric field instead of a magnetic field is employed, so that it is not necessary to consider the interference of the magnetic field as described above. Thereby, non-contact electric power transmission is realizable, without inhibiting rotation of rotor 13.

In particular, since the coils 24u to 24w of the rotating electrical machine 11 are connected to the rotating electrodes 51u to 51w, a resonance circuit is constituted by the coils 24u to 24w and the coupling capacitors Cu to Cw. Thereby, since the resonance phenomenon can be used, the power value transmitted through the coupling capacitors Cu to Cw can be improved. That is, the coils 24u to 24w for rotating the rotor 13 contribute to the performance improvement of non-contact power transmission using the coupling capacitors Cu to Cw. Therefore, non-contact power transmission can be suitably performed using the existing configuration of the rotating electrical machine 11.

(9) The rotor 13 is disposed inside the stator 14. In this case, since the stator 14 can exchange heat with components such as a housing, the stator 14 is more easily cooled than the rotor 13.

In a normal brushless rotating electrical machine, the stator is provided with a coil, and the rotor is a permanent magnet. For this reason, if the rotor is disposed inside the stator, the permanent magnet is likely to generate heat. Then, we are anxious about the magnetic force fall of a permanent magnet. However, a permanent magnet that can suppress a decrease in magnetic force due to heat generation tends to be expensive.

On the other hand, in the present embodiment, since the rotor 13 is provided with the coils 24u to 24w, the stator 14 can be a permanent magnet. Thereby, since a permanent magnet can be cooled suitably, the inconvenience mentioned above can be controlled. However, in the configuration in which the coils 24u to 24w are provided in the rotor 13, a configuration for supplying power to the rotating coils 24u to 24w is essential.

In this regard, in the present embodiment, as described above, the non-contact power transmission device 50 having the rotating electrodes 51u to 51w and the holding electrodes 52u to 52w is adopted as the power transmission to the coils 24u to 24w. Yes. As a result, it is possible to suitably transmit power to the coils 24u to 24w provided in the rotor 13 while suppressing wear of the rotating electrodes 51u to 51w and the holding electrodes 52u to 52w.

The above embodiment may be modified as follows.
One or both of the first rotating dielectric layer 61 and the first holding dielectric layer 71 may be omitted. For example, when both the first rotating dielectric layer 61 and the first holding dielectric layer 71 are omitted, the inter-electrode distance dx may be reduced accordingly. In this case, as already described, the opposing surfaces 51ua and 52ua are flat surfaces orthogonal to the axial direction of the rotating body 30. Since such a flat surface can be formed with relatively high accuracy, the electrodes are considered in consideration of local variations in the inter-electrode distance dx so that the u-phase rotating electrode 51u and the u-phase holding electrode 52u do not come into contact with each other. It is not necessary to secure a wide distance dx. Thereby, since the distance dx between electrodes can be made small, suppressing the contact of both opposing surface 51ua, 52ua, the electrostatic capacitance of u phase coupling capacitor Cu can be aimed at. However, if attention is paid to both the breakdown voltage and the electrostatic capacity, it is preferable that at least one of the both

dielectric layers

61 and 71 is provided.

In this example, it is preferable that the lubricating oil 80 be present between the two opposing surfaces 51ua and 52ua. Thereby, various inconveniences caused by sliding between the u-phase rotating electrode 51u and the u-phase holding electrode 52u can be suppressed.

In the embodiment, the non-contact power transmission device 50 is disposed inside the rotor 13, but is not limited thereto. For example, as illustrated in FIG. 6, the rotating body 30 may extend longer in the axial direction than the rotor 13, and a part of the rotating body 30 may protrude from the rotor 13. Then, each phase unit 50u to 50w of the non-contact power transmission device 50 may be provided in a portion protruding from the rotor 13 in the rotating body 30.

As shown in FIG. 7, the non-contact power transmission device 50 holds the u-phase holding electrode 52 u so that it can move in the axial direction of the rotating body 30 and does not rotate as the rotating body 30 rotates. A link mechanism 91 may be provided. Further, as shown in FIG. 7, the non-contact power transmission device 50 includes a plurality of coil springs 92 connected to the u-phase wall portion 84 u and the second holding dielectric layer 72 instead of the u-phase disc spring 83 u. May be. Further, instead of the coil spring 92, an arbitrary elastic member such as elastic rubber (rubber) may be used. In short, as long as the “holding portion” and the “pressing portion” can exhibit their functions, their specific configurations are arbitrary.

○ The u-phase holding electrode 52u may be held in a state in which it cannot move in the axial direction of the rotating body 30. For example, the u-phase holding electrode 52u may be configured to be attached to the rotating body 30 via a bearing, or may be configured to be fixed to the inner peripheral surface of the holding member 81. In short, the u-phase holding electrode 52u only needs to be held so as not to rotate as the rotating body 30 rotates.

The disc springs 83u to 83w and the wall portions 84u to 84w may be omitted. In this case, the both

dielectric layers

61 and 71 may be arranged to face each other with a minute interval in the axial direction of the rotating body 30.
As already described, the surface of the first rotating dielectric layer 61 and the surface of the first holding dielectric layer 71 are flat surfaces orthogonal to the axial direction of the rotating body 30. Since such a flat surface can be formed with relatively high accuracy, the distance between the two

dielectric layers

61 and 71 can be reduced while the contact between the two

dielectric layers

61 and 71 is suppressed accordingly. Therefore, it is possible to improve the capacitance of the u-phase coupling capacitor Cu while suppressing contact between both the

dielectric layers

61 and 71. In this other example, the lubricating oil 80 may or may not be present between the both

dielectric layers

61 and 71.

O Dielectric ceramic particles such as barium titanate may be mixed in the lubricating oil 80. Thereby, the dielectric constant of the lubricating oil 80 can be improved.
O The lubricating oil 80 may be omitted, and both

dielectric layers

61 and 71 may be in contact with each other. In this case, both

dielectric layers

61 and 71 slide. As already described, since the friction coefficient of both

dielectric layers

61 and 71 is smaller than the friction coefficient of the u-phase rotating electrode 51u and the u-phase holding electrode 52u, the u-phase rotating electrode 51u and the u-phase holding electrode 52u slide. Compared with the structure to perform, the abrasion and noise resulting from sliding can be suppressed. A coating layer having a smaller coefficient of friction than both

dielectric layers

61 and 71 may be separately provided on the surfaces of both

dielectric layers

61 and 71.

O At least one of the second rotating dielectric layer 62 and the second holding dielectric layer 72 may be omitted.
In place of the fluid lubricating oil 80, a solid lubricant (for example, tetrafluoroethylene resin or polyphenylene sulfide) may be provided.

○ The u-phase rotating electrode 51u and the u-phase holding electrode 52u are circular rings as viewed from the axial direction of the rotating body 30, but are not limited thereto, and may be, for example, a rectangular ring. Further, the outer diameter of the u-phase rotating electrode 51u and the outer diameter of the u-phase holding electrode 52u may be different.

The dielectric part provided in both opposing surfaces 51ua and 52ua may be a laminated structure of a plurality of dielectric layers having different dielectric constants.
A cut extending in the radial direction may be formed in the rotating electrodes 51u to 51w and the holding electrodes 52u to 52w. In short, the shapes of the rotating electrodes 51u to 51w and the holding electrodes 52u to 52w are not limited to a closed state without a break.

In the embodiment, one coupling capacitor is provided for one coil. However, the present invention is not limited to this, and a plurality of coupling capacitors may be provided for one coil. In this case, power transmission may be performed by connecting a plurality of coupling capacitors in series or in parallel.

The stator 14 is not limited to a permanent magnet, and may be composed of a core and a coil. In this case, the permanent magnet can be omitted.
A coil may be separately provided on a connection line connecting the inverter 100 and the holding electrodes 52u to 52w.

○ The mounting position of the inverter 100 is arbitrary, and may be integrated with the rotating electrical machine 11, for example, or may be provided separately from the rotating electrical machine 11. The same applies to the battery B.

The connection mode of the coils 24u to 24w is not limited to the delta connection, and may be a Y connection, for example.
In embodiment, the non-contact electric power transmission apparatus 50 was attached to the rotary body 30, However, It is not restricted to this, What is necessary is just to be attached to what rotates with rotation of the rotor 13. FIG. For example, the non-contact power transmission device 50 may be attached to the rotating shaft 12 or the main body 21 of the rotor 13.

○ The rotary electric machine 11 may be a double rotor type having one stator and two rotors. The double rotor type structure will be briefly described with reference to FIGS. In FIG. 8, for convenience of illustration, the rotating body 30 and the holding member 81 are shown in a side view, and both the

rotors

13 and 120 and the stator 110 are shown in a sectional view.

As shown in FIGS. 8 and 9, the rotating electrical machine 11 includes a stator 110 provided on the radially outer side with respect to the rotor 13 (hereinafter referred to as the first rotor 13), and between the first rotor 13 and the stator 110. And a second rotor 120 provided. The second rotor 120 has a cylindrical shape that is slightly larger than the first rotor 13 (specifically, a cylindrical shape), and the stator 110 has a cylindrical shape that is slightly larger than the second rotor 120 (details). Is cylindrical). Both

rotors

13 and 120 and the stator 110 are arranged on the same axis, and are arranged in the order of the first rotor 13 → the second rotor 120 → the stator 110 from the inner side to the outer side in the radial direction.

The stator 110 has a cylindrical stator core 111. As shown in FIG. 9, a plurality of slots 112 are arranged in the circumferential direction of the stator core 111 on the inner peripheral surface of the stator core 111. The stator 110 has a plurality of coils 113u to 113w wound around a plurality of slots 112. Each of the coils 113u to 113w is connected to the battery B via an inverter different from the inverter 100.

As shown in FIGS. 8 and 9, the second rotor 120 has a predetermined interval with respect to the inner circumferential surface 120 a that is radially opposed to the first rotor 13 with a predetermined interval and the stator 110. It has the outer peripheral surface 120b which is spaced apart and opposes to radial direction. Moreover, as shown in FIG. 9, the 2nd rotor 120 has the permanent magnet 121 as what generates a magnetic field. The permanent magnet 121 is embedded in the second rotor 120.

When both the rotating electrical machine 11 and the engine are mounted on the vehicle, for example, the first rotor 13 is connected to the drive shaft of the engine, and the second rotor 120 is connected to the axle.
According to such a configuration, the first rotor 13 and the second rotor 120 cooperate to function as the first rotating electrical machine, and the second rotor 120 and the stator 110 cooperate to function as the second rotating electrical machine. To do. Specifically, for example, when the first rotor 13 is connected to the drive shaft of the engine and the second rotor 120 is connected to the axle as described above, power is supplied from the battery B to the coils 113u to 113w of the stator 110. By supplying, the 2nd rotor 120 can be rotated and a vehicle can be driven through it.

On the other hand, the first rotor 13 can be rotated by the power of the engine. In this case, under a predetermined condition, an induced current flows through each of the coils 24u to 24w of the first rotor 13, the second rotor 120 is rotated by the interaction between the dielectric current and the magnetic flux of the permanent magnet 121, and the axle is rotated. To do. That is, the engine power is transmitted to the second rotor 120 and used for traveling of the vehicle. Further, AC power generated in each of the coils 24 u to 24 w is taken out via the non-contact power transmission device 50. The extracted AC power is input to the inverter 100 and used for charging the battery B, for example.

As described above, in a configuration in which the two

rotors

13 and 120 are present, it is necessary to provide a coil in either one of the

rotors

13 and 120 in order to perform rotation control or the like. In the configuration in which the second rotor 120 is disposed between the first rotor 13 and the stator 110, providing a coil in the second rotor 120 tends to complicate the configuration. Therefore, a device that performs power transmission tends to be complicated.

On the other hand, by providing the first rotor 13 with the coils 24u to 24w, the second rotor 120 can employ the permanent magnet 121 to generate a magnetic field. Thereby, complication of composition can be controlled. In this case, a configuration for transmitting power to the coils 24u to 24w of the rotating first rotor 13 is essential. On the other hand, by adopting the non-contact power transmission device 50 as a power transmission to the coils 24u to 24w, the power transmission can be performed without using a slip ring or a brush. As a result, inconveniences unique to contact-type power transmission such as brush wear can be avoided. From the above, in the configuration having the two

rotors

13 and 120, the rotating electrical machine 11 can be suitably driven while achieving brushlessness and suppressing the complexity of the configuration.

The connection destination of the rotating electrodes 51u to 51w, that is, the load is not limited to the coils 24u to 24w, but is arbitrary.
The application target of the non-contact power transmission device 50 is not limited to the rotating electrical machine 11 and is arbitrary. For example, the non-contact power transmission device 50 may be applied to supply power to a load provided on the rotating body.

In the embodiment, the contactless power transmission device 50 has the three units 50u to 50w because of the application to the three-phase AC motor, but is not limited thereto, and may have a configuration having two units. In short, the number of units may be set corresponding to the load.

Claims

A rotating electrode in the form of a flat plate ring fixed to a rotatable rotating body and projecting radially from the outer peripheral surface of the rotating body;
A plate ring-shaped holding electrode that has an insertion hole through which the rotating body is inserted and is held so as not to rotate with the rotation of the rotating body;
With
The rotating electrode and the holding electrode constitute a coupling capacitor by being opposed to each other in the axial direction of the rotating body,
A non-contact power transmission device in which non-contact power transmission is performed via the coupling capacitor.
The rotation electrode has a rotation facing surface facing the holding electrode, the holding electrode has a holding facing surface facing the rotation electrode, and at least one of the rotation facing surface and the holding facing surface The contactless power transmission device according to claim 1, wherein a dielectric portion having a dielectric constant higher than that of air is provided.
The non-contact power transmission device according to claim 1, wherein a lubricant is disposed between the rotating electrode and the holding electrode.
The lubricant is a fluid lubricant;
The non-contact power transmission device is
A holding unit that holds the holding electrode in a state that is movable in the axial direction of the rotating body and does not rotate with the rotation of the rotating body;
The non-contact power transmission device according to claim 3, further comprising: a pressing portion that presses the holding electrode toward the rotating electrode from an axial direction of the rotating body.
The dielectric portion includes a rotating dielectric portion provided on the rotation facing surface, and a holding dielectric portion provided on the holding facing surface,
The contactless power transmission device according to claim 2, wherein each of the rotating dielectric portion and the holding dielectric portion has a flat surface orthogonal to the axial direction of the rotating body.
The contactless power transmission device according to claim 5, wherein a friction coefficient of the rotating dielectric part and the holding dielectric part is smaller than a friction coefficient of the rotating electrode and the holding electrode.
A rotor provided with a coil;
The non-contact power transmission device according to any one of claims 1 to 6,
A rotating electric machine with
The rotating electrode is a rotating electrical machine connected to the coil.
The rotor is a cylindrical first rotor;
A stator provided radially outward with respect to the first rotor;
A cylindrical second rotor provided between the first rotor and the stator and having an inner peripheral surface facing the first rotor and an outer peripheral surface facing the stator;
With
The rotating electrical machine according to claim 7, wherein the second rotor has a permanent magnet.