Power supply device having power supply part for non-contact power supply to rotor

Abstract

To provide a non-contact power supply technique that can be suitably used for a motor that requires a large amount of electric power to be supplied to a rotor and requires a high number of revolutions.SOLUTION: A power supply device 90 of the present invention is a power supply device 90 having a power supply part that supplies electric power to a rotor 310 in a non-contact manner. A power supply part Tr includes a power transmission part 71 that transmits the electric power to the rotor 310 side; and a power reception part 72 that is provided on the rotor 310 side and receives the electric power in the non-contact manner with the power transmission part 71. The power reception part 72 includes a power reception-side core 722 that includes an annular recess part that accommodates a coil and includes an opening part of the annular recess part on the power transmission part 71 side, and an outer peripheral member 723 that is provided so as to cover the outer periphery of the power reception-side core 722.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a power supply device having a power supply unit that contactlessly supplies power to a rotor. [Background technology]

[0002] In recent years, wireless power supply technology (also known as contactless power supply technology) has come to be used in a variety of industries (e.g., robotics, energy, automobiles, etc.), and can also be used to supply power to the rotor of a motor that has windings instead of a permanent magnet in the rotor (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Roman Manko et al., “Analysis and Design of Rotary Transformer for Wireless Power Transmission”, “IEEE Problems of Automated Electrodrive. Theory and Practice(PAEP)”, (Date'21-25 Sept), 2020. Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in the case of a drive motor for an automobile or the like, in which windings are arranged on a rotor, for example, the rotor is supplied with power of about several kW.

[0005] When power is supplied to this rotor using contactless power supply technology, the core of the transformer for contactless power supply becomes large enough to supply power of around several kW.

[0006] On the other hand, in the case of drive motors for automobiles, etc., high rotation speeds (approximately 20,000 rpm) are required, and the core used for contactless power supply to the rotor is subjected to a large load due to centrifugal force. However, there is a problem in that cores made of materials that provide good electrical properties do not have enough strength.

[0007] Therefore, there is a demand for a contactless power supply technology that can be suitably used in motors that require a large amount of power supply to the rotor and a high rotation speed (for example, drive motors for automobiles, etc.).

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a contactless power supply technology that can be suitably used in motors and the like that require a large amount of power supply to the rotor and a high rotation speed. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention is realized by the following configuration. The power supply device of the present invention comprises: A power supply device having a power supply unit that contactlessly supplies power to a rotor, The power supply unit is a power transmission unit that transmits power to the rotor side; a power receiving unit provided on the rotor side and configured to receive power in a non-contact manner from the power transmitting unit, The power receiving unit is a power receiving core having an annular recess for accommodating a coil, the annular recess having an opening on the power transmitting unit side; and an outer peripheral member provided to cover the outer periphery of the power receiving side core. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a contactless power supply technology that can be suitably used for motors and the like that require a large amount of power supply to the rotor and a high rotation speed. [Brief explanation of the drawings]

[0011] [Figure 1]1 is a configuration diagram showing a vehicle drive system in which contactless power feeding by a power feeding device of a first embodiment according to the present invention is applied to feeding power to a rotor of a rotating electric machine. [Figure 2] 1 is a schematic cross-sectional view showing a part of a cross section of a rotating electric machine according to a first embodiment of the present invention. [Figure 3] 1 is a schematic cross-sectional view showing the configuration of a rotating electric machine including a power supply unit according to a first embodiment of the present invention and its surroundings. [Figure 4] 1 is a schematic perspective view, partially in section, of a power supply section according to a first embodiment of the present invention. [Figure 5] 5A and 5B are diagrams for explaining the effect based on analysis results when the outer peripheral member of the first embodiment according to the present invention is provided. [Figure 6] FIG. 10 is a diagram for explaining the range in which an outer peripheral member is provided in the second embodiment according to the present invention. [Figure 7] 10 is a graph showing a range in which no outer peripheral member is provided according to a second embodiment of the present invention, and a change in stress at an inner corner of a recess when compressive stress is changed. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a mode for carrying out the present invention (hereinafter referred to as an "embodiment") will be described in detail with reference to the accompanying drawings. It should be noted that the same elements are denoted by the same numbers or symbols throughout the description of the embodiments. Furthermore, the dimensional ratios in the drawings differ from the actual dimensional ratios and are merely drawn to make the explanation easier to understand, and do not guarantee that the same parts are drawn to the same dimensions between drawings. Furthermore, in the drawings, for ease of viewing, there are cases where only some of the parts having the same attribute are given reference symbols.

[0013] (First embodiment) FIG. 1 is a configuration diagram showing, as an application example, a vehicle drive system 1 in which contactless power supply by a power supply device 90 of a first embodiment according to the present invention is applied to supply power to a rotor 310 of a rotating electric machine 3 (see FIGS. 2 and 3). FIG. 2 is a schematic cross-sectional view showing a part of a cross section of the rotating electric machine 3 according to the first embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing the configuration of the vicinity of a rotary electric machine 3 including a power supply unit Tr according to a first embodiment of the present invention.

[0014] As shown in FIG. 1, the vehicle drive system 1 has a dual power supply configuration including a low-voltage battery 2A and a high-voltage battery 2B, and includes a vehicle drive device 1A. The vehicle drive system 1A includes a rotating electric machine 3 (motor) and a drive system 5.

[0015] The low-voltage battery 2A is, for example, a lead battery, and has a rated voltage of, for example, 12V.

[0016] The high-voltage battery 2B is, for example, a lithium-ion battery, and has a rated voltage significantly higher than that of the low-voltage battery 2A, for example, a rated voltage of 40V or more. In this embodiment, as an example, the rated voltage of the high-voltage battery 2B is 300V or higher. The high-voltage battery 2B may be in the form of a fuel cell or the like.

[0017] As shown in FIGS. 2 and 3, the rotating electric machine 3 includes a rotor 310 and a stator 320 provided radially outward of the rotor 310.

[0018] The rotor 310 is a wound field type, and includes a rotor shaft 314, a rotor core 312 provided on the rotor shaft 314, and a rotor coil 316 provided on the rotor core 312, as shown in FIG. The rotor coil 316 is formed by winding a coil wire for a field coil around the rotor core 312 . Specifically, as shown in FIG. 2, rotor core 312 has teeth 3122 that protrude radially outward, and coil wire for a field coil that forms rotor coil 316 is wound around teeth 3122.

[0019] The stator 320 includes a stator core 321 having teeth 3210 and a stator coil 322 having a coil wire wound around the teeth 3210 .

[0020] As shown in FIG. 1, the driving device 5 includes a microcomputer 50 (hereinafter referred to as “microcomputer 50”) and an electric circuit section 60.

[0021] The microcomputer 50 may be realized as, for example, an ECU (Electronic Control Unit). The microcomputer 50 is connected to various electronic components (other ECUs and sensors) in the vehicle via a network 6 such as a CAN (Controller Area Network). The microcomputer 50 receives various commands such as control commands from a higher-level ECU (not shown) via the network 6. The microcomputer 50 then controls the rotating electrical machine 3 via the electric circuit unit 60 based on the control command. The microcomputer 50 operates on the basis of power from the low-voltage battery 2A.

[0022] The electric circuit section 60 includes a smoothing capacitor 62 , a power conversion circuit section 63 , a power feeding circuit section 64 , and a power receiving circuit section 65 .

[0023] The power supply circuit section 64 and the power receiving circuit section 65, together with a power supply section Tr which is a transformer, form a power supply device 90 which supplies power to the rotor coil 316 in a non-contact manner. This differs from a contact-type power supply configuration in that there is no wear, and reliability (durability, etc.) can be improved.

[0024] The power supply unit Tr has a power transmitting coil 711 (primary coil) and a power receiving coil 721 (secondary coil).

[0025] The smoothing capacitor 62 is provided between the high potential side line 20 and the low potential side line 22 of the high voltage battery 2B. A resistor R0 for passive discharge may be connected across the smoothing capacitor 62.

[0026] The power conversion circuit unit 63 is in the form of an inverter, and forms, for example, a three-phase bridge circuit. The power conversion circuit unit 63 supplies three-phase AC power to the stator 320 (see FIG. 2) of the rotating electrical machine 3 under the control of the microcomputer 50. The power conversion circuit unit 63 is connected between the high potential side line 20 and the low potential side line 22 in a manner that the power conversion circuit unit 63 is in parallel with the smoothing capacitor 62 . The power conversion circuit unit 63 includes each switching element SW3 of the high-potential side arm, each switching element SW4 of the low-potential side arm, and a drive circuit unit 52 (e.g., a gate driver IC) that drives each switching element SW3 and each switching element SW4 based on a control signal from the microcomputer 50.

[0027] The power supply circuit section 64 includes a bridge circuit section 641 and a drive circuit section 642 .

[0028] The bridge circuit section 641 is connected between the high potential side line 20 and the low potential side line 22 in parallel with the smoothing capacitor 62 and the resistor R0 for passive discharge. The bridge circuit section 641 is in the form of a full bridge circuit, and includes switching elements SW1-1 and SW1-2 and switching elements SW2-1 and SW2-2.

[0029] The switching elements SW1-1 and SW1-2 are connected in series between a high potential side line 20 and a low potential side line 22. One end of the power transmitting coil 711 is connected between the switching elements SW1-1 and SW1-2. Furthermore, the switching elements SW2-1 and SW2-2 are connected in series between the high potential side line 20 and the low potential side line 22 in a manner that they are in parallel with the switching elements SW1-1 and SW1-2. The other end of the power transmitting coil 711 is connected between the switching elements SW2-1 and SW2-2.

[0030] The switching elements SW1-1, SW1-2, SW2-1, and SW2-2 are switched between on and off states via the drive circuit section 642. The switching elements SW1-1, SW1-2, SW2-1, and SW2-2 change the state of conduction to the power transmitting coil 711 under the control of the drive circuit unit 642.

[0031] The switching elements SW1-1, SW1-2, SW2-1, and SW2-2 are, for example, IGBTs (Insulated Gate Bipolar Transistors), but may be of other types such as MOSFETs (Metal Oxide Semiconductor Field-Effect Transistors).

[0032] The drive circuit unit 642 supplies power to the rotor coil 316 via the power receiving circuit unit 65 by driving the switching elements SW1-1, SW1-2, SW2-1, and SW2-2 based on a control signal from the microcomputer 50.

[0033] The power receiving circuit section 65 includes a rectifier circuit 652 .

[0034] The rectifier circuit 652 is electrically connected between the power supply unit Tr (more specifically, the power receiving unit 72) and the rotor coil 316. The rectifier circuit 652 rectifies the current (drive current) on the secondary side of the power supply unit Tr and supplies it to the rotor coil 316. The rectifier circuit 652 may be a diode bridge circuit as shown in FIG.

[0035] FIG. 4 is a schematic perspective view, partially in section, of a power supply unit Tr according to a first embodiment of the present invention. In the following description, the direction in which the central axis I of the rotor 310 extends will be referred to as the thrust direction (see FIGS. 3 and 4).

[0036] As shown in FIG. 4, the thrust direction is further expressed with a direction included, where the thrust direction is toward the rotor 310 (right side of FIG. 4) and is referred to as the first thrust direction, and the thrust direction is away from the rotor 310 (left side of FIG. 4) and is referred to as the second thrust direction.

[0037] As shown in FIGS. 3 and 4, the power supply unit Tr includes a power transmitting unit 71 and a power receiving unit 72 arranged side by side in the thrust direction. Specifically, as shown in Figures 3 and 4, the power supply unit Tr includes a power transmission unit 71 that transmits power to the rotor 310 side, and a power receiving unit 72 that is provided on the rotor 310 side so as to be spaced apart from the power transmission unit 71 in the first thrust direction (the direction approaching the rotor) and receives power without contact with the power transmission unit 71.

[0038] The power transmitting unit 71 includes a power transmitting coil 711 and a power transmitting core 712 having an opening of a recess 7121 for accommodating the power transmitting coil 711 facing the power receiving unit 72 side.

[0039] As shown in FIG. 3, the power receiving unit 72 includes a power receiving coil 721 and a power receiving core 722 provided on the rotor shaft 314 so that the opening of a recess 7221 that houses the power receiving coil 721 faces the power transmitting unit 71 side. In this embodiment, the outer diameter of a portion of the rotor shaft 314 is increased, and the power receiving side core 722 is fixed thereto (for example, by press-fitting or adhesively fixing), but this is not limitative. For example, the outer diameter of the rotor shaft 314 may remain unchanged, and a spacer or the like may be provided between the rotor shaft 314 and the power receiving side core 722 .

[0040] In this embodiment, the power transmitting side core 712 and the power receiving side core 722 are ferrite cores made of ferrite, but may be dust cores made of sendust, for example. If the power transmitting core 712 and the power receiving core 722 are made of ferrite, good electrical characteristics can be obtained.

[0041] As shown in FIG. 4, the power transmitting core 712 is a cylindrical member having a recess 7121 with a rectangular cross section, and the power transmitting core 712 has an annular recess (recess 7121) that accommodates the power transmitting coil 711. The power transmitting side core 712 is spaced apart from the power receiving side core 722 in the thrust direction (more specifically, in the second thrust direction away from the rotor 310).

[0042] Similarly, as shown in FIG. 4, the power receiving side core 722 is a cylindrical member having a recess 7221 with a rectangular cross section, and the power receiving side core 722 has an annular recess (recess 7221) that accommodates the power receiving side coil 721.

[0043] The recess 7121 of the power-transmitting-side core 712 and the recess 7221 of the power-receiving-side core 722 are both open in the thrust direction.

[0044] More specifically, the recess 7121 of the power transmitting side core 712 opens in a first thrust direction toward the rotor 310, and conversely, the recess 7221 of the power receiving side core 722 opens in a second thrust direction away from the rotor 310.

[0045] In other words, the transmitting side core 712 has an opening (also called an opening portion) of the annular recess (recess 7121) on the receiving side of the power receiving unit 72, and the receiving side core 722 has an opening (also called an opening portion) of the annular recess (recess 7221) on the transmitting side of the power transmitting unit 71.

[0046] Thus, the power transmitting side core 712 has an annular recess (recess 7121) that houses the power transmitting side coil 711, and also has an opening (also called an opening) of the annular recess on the power receiving section 72 side. Similarly, the power receiving side core 722 has an annular recess (recess 7221) that houses the power receiving side coil 721, and also has an opening (also called an opening) of the annular recess (recess 7221) on the power transmitting unit 71 side.

[0047] As a result, the opening (opening) of the annular recess (recess 7121) of the power transmitting side core 712 faces the opening (opening) of the annular recess (recess 7221) of the power receiving side core 722.

[0048] As shown in FIG. 4, the end faces of both the power transmitting side core 712 and the power receiving side core 722 are such that the width of the inner end face IEf on the opening side is wider than the width of the outer end face OEf, so that the magnetic flux densities of the magnetic flux passing through the outside and the magnetic flux passing through the inside are approximately the same.

[0049] The power receiving section 72 further includes an outer peripheral member 723 that is provided to cover the outer periphery of the power receiving core 722, and is configured to increase the strength to withstand the load applied to the power receiving core 722 by centrifugal force.

[0050] More specifically, when the rotor 310 rotates, the power receiving side core 722 also rotates, and the load applied to the power receiving side core 722 at this time acts as a force that expands the diameter of the power receiving side core 722.

[0051] Therefore, by providing an outer peripheral member 723 on the outer periphery of the power receiving side core 722 to resist this radially expanding force, the load acting on the power receiving side core 722 can be reduced efficiently.

[0052] Therefore, there is no need to develop materials that increase strength while maintaining good electrical properties, and conventional materials that already provide good electrical properties can be used for the power receiving side core 722 as is.

[0053] For example, when considering a power supply of about several kW, the outer diameter of the power receiving core 722 becomes close to 100 mmφ, and a large load is applied to the power receiving core 722 due to centrifugal force.

[0054] A great deal of effort is required to develop new materials that are strong enough to withstand such large loads and that can maintain their electrical properties.

[0055] However, in this embodiment, the outer peripheral member 723 reduces the load on the power receiving side core 722, and the outer peripheral member 723 provided separately from the power receiving side core 722 has a high degree of freedom in the selection of materials.

[0056] Furthermore, merely providing the outer peripheral member 723 will somewhat reduce the load on the receiving core 722, but for example, by selecting a material with a high Young's modulus for the outer peripheral member 723, the load on the receiving core 722 can be suitably reduced.

[0057] Next, the effects of providing the outer peripheral member 723 will be explained while showing the analysis results. FIG. 5 is a diagram for explaining the effect based on the analysis results when the outer peripheral member 723 according to the first embodiment of the present invention is provided. FIG. 5A shows a comparative example in which the outer peripheral member 723 is not provided, and FIG. 5B shows a case in which the outer peripheral member 723 is provided.

[0058] In Figure 5, the up and down direction is the thrust direction described above, and the power receiving side core 722 has a recess 7221 with a bottom at approximately the halfway point when viewed in the thickness direction (thrust direction) perpendicular to the radial direction. In other words, the depth of the recess 7221 is approximately half the thickness of the power receiving side core 722 .

[0059] Since stress tends to concentrate at corners, Figure 5 shows the stress at the inner corners of the radially inner recess 7221 (hereinafter, the radially inner side may be omitted) when the power receiving side core 722 is rotated at approximately 20,000 rpm.

[0060] 5B shows a case where the material of the outer peripheral member 723 is CFRP (carbon fiber reinforced plastic), and the outer peripheral member 723 applies a compressive stress of about 4 MPa to the power receiving side core 722.

[0061] As can be seen from Figure 5, when the outer peripheral member 723 is not provided, a stress of 48 MPa (see Figure 5(A)) is applied to the inner corner of the recess 7221, but by providing the outer peripheral member 723, the stress is reduced to 30 MPa (see Figure 5(B)).

[0062] Incidentally, since centrifugal force also increases with an increase in weight, it is preferable to use a strong and lightweight material for the outer peripheral member 723, and from this point of view, it is preferable to use FRP (fiber reinforced plastic).

[0063] Furthermore, as current flows through the receiving coil 721, the receiving core 722 generates heat, so CFRP (carbon fiber reinforced plastic), which is an FRP made of carbon material that is less susceptible to deformation (shrinkage, expansion, etc.) due to heat, is thought to be the ideal material for the outer member 723.

[0064] (Second embodiment) Next, a second embodiment of the present invention will be described. The second embodiment also has the same basic configuration as the first embodiment, and the following description will omit the same points as the first embodiment and will mainly focus on the points that are different.

[0065] The second embodiment differs from the first embodiment in that the outer peripheral member 723 changes the compressive stress applied to the receiving side core 722, and in that the range in which the outer peripheral member 723 is provided on the receiving side core 722 is changed when viewed in the thickness direction (thrust direction) perpendicular to the radial direction.

[0066] FIG. 6 is a diagram for explaining the range in which an outer peripheral member 723 according to the second embodiment of the present invention is provided.

[0067] In Figure 6, the up and down direction is the thrust direction described above, but in this embodiment, as shown in Figure 6, the outer peripheral member 723 is located in a portion that overlaps with the recess 7221 when viewed in the thrust direction (the outer peripheral portion that overlaps with the recess 7221 in the thrust direction), and is not located in a predetermined range (X% range) on the opening side. That is, the outer peripheral member 723 is not provided in a predetermined range (a range of X%) on the opening (also called an opening portion) side of the recess 7221 (also called an annular recess). In other words, the outer peripheral member 723 is not provided within a predetermined range (X% range) of the outer peripheral portion on the opening side from the bottom (inner bottom) of the recess 7221.

[0068] As can be seen from FIG. 6, the case where the outer peripheral member 723 is provided over the entire outer periphery of the power receiving side core 722 in the thrust direction is taken as 100%. Therefore, the fact that the outer peripheral member 723 is not provided within a range of X% on the opening side also means that the outer peripheral member 723 is provided within a range of Y% (=100%-X%) in the direction from the end face UEf of the power receiving side core 722 located opposite the opening side toward the opening side (the second thrust direction away from the rotor 310).

[0069] FIG. 7 is a graph showing the change in stress at the inner corner of the recess 7221 when the compressive stress is changed and in the area where the outer peripheral member 723 of the second embodiment according to the present invention is not provided. The graph in Figure 7 shows the cases of a 0% range where the outer peripheral member 723 is not provided (X = 0%, which is the same as that shown in the first embodiment), a 20% range where the outer peripheral member 723 is not provided (X = 20%), a 30% range where the outer peripheral member 723 is not provided (X = 30%), and a 40% range where the outer peripheral member 723 is not provided (X = 40%).

[0070] In the graph of Figure 7, the horizontal axis shows the compressive stress (MPa) that the outer peripheral member 723 applies to the receiving side core 722, and the vertical axis shows the stress (MPa) applied to the inner corner of the recess 7221, as shown in the first embodiment.

[0071] As explained above, the depth of the recess 7221 is approximately half the thickness of the power receiving side core 722. Therefore, when the range Z of only the portion of the outer peripheral member 723 that overlaps with the recess 7221 when viewed in the thrust direction is taken as 100%, the ranges of the graph for X=20, 30, and 40% become Z=40%, 60%, and 80%, respectively.

[0072] First, when the compressive stress is 6 MPa, it can be seen that the smaller the area where the outer peripheral member 723 is not provided, that is, the more the outer peripheral member 723 is provided over the entire outer peripheral area of ​​the receiving side core 722, the smaller the stress at the inner corner of the recess 7221 becomes.

[0073] This trend is also seen when the compressive stress is 8 MPa, and it can be seen that if the compressive stress applied by the outer peripheral member 723 to the receiving side core 722 is the same, the more the outer peripheral member 723 is provided over the entire outer periphery of the receiving side core 722, the more effective it is in reducing the stress at the inner corners of the recess 7221.

[0074] On the other hand, when the range of the outer peripheral member 723 provided on the outer periphery of the receiving side core 722 is the same, it can be seen that as the compressive stress applied to the receiving side core 722 by the outer peripheral member 723 increases, the effect of reducing the stress at the inner corner of the recess 7221 is obtained.

[0075] Therefore, from the sole perspective of reducing stress at the inner corners of the recess 7221, it is preferable to provide the outer peripheral member 723 over the entire outer periphery of the receiving side core 722, and to configure the outer peripheral member 723 to apply a large compressive stress to the receiving side core 722.

[0076] For example, to make the outer peripheral member 723 apply a large compressive stress to the power receiving side core 722, carbon fibers or the like can be wound around the power receiving side core 722 while applying tension corresponding to the compressive stress, and in this state, the carbon fibers or the like can be impregnated with resin to fix the outer peripheral member 723 made of CFRP.

[0077] Another method for causing the outer peripheral member 723 to apply a large compressive stress to the receiving side core 722 is, for example, to first fabricate an outer peripheral member 723 having an inner diameter smaller than that of the receiving side core 722, and then perform a cold fitting in which the receiving side core 722 is cooled to cause it to shrink and then fitted into the outer peripheral member 723. The inner diameter of the outer peripheral member 723 is set so that a desired compressive stress is applied when the power receiving side core 722 returns to room temperature and returns to its original size.

[0078] In particular, carbon is resistant to deformation (shrinkage, expansion, etc.) due to temperature, making CFRP a material that is also resistant to deformation due to temperature changes. Therefore, if the outer peripheral member 723 is made of CFRP, it is recommended to cool the power receiving side core 722, shrink the power receiving side core 722, and then perform a cold fitting to fit the outer peripheral member 723.

[0079] However, as briefly mentioned in the first embodiment, there is a problem in that the power receiving side core 722 generates heat as current flows through the power receiving side coil 721. As mentioned above, FRP (fiber reinforced plastic) is lightweight and strong, making it suitable as a material to be used for the outer peripheral member 723, but it has the drawback of not being good at dissipating heat.

[0080] Therefore, taking heat generation into further consideration, it is preferable to ensure heat dissipation by arranging the outer peripheral member 723 in the portion that overlaps with the recess 7221 when viewed in the thrust direction, but not in a specified range (X% range) on the opening side, assuming that the stress at the inner corner of the recess 7221 can be sufficiently reduced.

[0081] For example, if the power receiving side core 722 is made of a ferrite core, there is a risk of it being damaged if a mechanical stress exceeding 44 MPa is applied. From this, when a safety factor of about 1.5 to 2.0 is taken into consideration, if the stress on the ferrite core can be reduced to less than 22 MPa, there is almost no risk of breakage.

[0082] Therefore, for example, if the compressive stress applied by the outer peripheral member 723 to the power receiving side core 722 is 6 MPa, the outer peripheral member 723 may not be provided within 30% of the range on the opening side to ensure heat dissipation.

[0083] In this way, in relation to the compressive stress that the outer peripheral member 723 applies to the receiving side core 722, it is preferable that the stress on the receiving side core 722 is kept below 22 MPa, and that the outer peripheral member 723 is arranged in a portion that overlaps with the recess 7221 when viewed in the thrust direction, but is not arranged in a specified range on the opening side, thereby improving heat dissipation.

[0084] Furthermore, if the outer peripheral member 723 is not provided in a portion that does not overlap with the recess 7221 when viewed in the thrust direction, that is, in this embodiment, beyond X=50%, the effect of reducing stress at the inner corner of the recess 7221 will be significantly reduced, so it is preferable that the outer peripheral member 723 is located in a portion that at least partially overlaps with the recess 7221 when viewed in the thrust direction.

[0085] Further, although not as severe as the inner corners of the recess 7221, stress due to centrifugal force also tends to be applied to the radially inner side of the end face UEf side of the power receiving side core 722 located opposite the opening side. For this reason, it is desirable to extend the outer peripheral member 723 up to the position on the end face UEf side of the receiving side core 722, which is located opposite the opening side, as shown in Figure 6, so as to reduce the stress acting radially inward on the end face UEf side of the receiving side core 722.

[0086] As a specific example of the power supply section Tr, the case of an axial type in which the power transmitting core 712 and the power receiving core 722 are provided in the thrust direction has been described. On the other hand, there is also a radial type in which the power transmitting side core 712 is provided radially outside the power receiving side core 722. However, in the axial type, the power receiving core 722 that rotates is larger, so the effect of providing the outer peripheral member 723 is greater.

[0087] The present invention has been described above based on specific embodiments, but the present invention is not limited to the above embodiments, and modifications and improvements to the embodiments are also included within the technical scope of the invention, which will be clear to those skilled in the art from the description of the claims. [Explanation of symbols]

[0088] 310... rotor (wound field rotor), Tr... power supply unit (transformer), 71... power transmission unit, 712... power transmission side core, 7121... recess (annular recess), 72... power receiving unit, 722... power receiving side core, 7221... recess (annular recess), 723... outer peripheral member, 90... power supply device

Claims

1. A power supply device having a power supply unit that contactlessly supplies power to a rotor, The power supply unit is a power transmission unit that transmits power to the rotor side; a power receiving unit provided on the rotor side and configured to receive power in a non-contact manner from the power transmitting unit, The power receiving unit is a power receiving core having an annular recess for accommodating a coil, the annular recess having an opening on the power transmitting unit side; an outer peripheral member provided to cover an outer periphery of the power receiving side core.

2. The power supply device according to claim 1 , wherein the power transmitting unit and the power receiving unit are aligned in a thrust direction.

3. The power supply device according to claim 2 , wherein the outer peripheral member is not provided in a predetermined range on the opening side.

4. The power supply device according to claim 1 , wherein the outer peripheral member is made of fiber-reinforced plastic.

5. The power supply device according to claim 1 , wherein the power receiving side core is made of ferrite.

6. The power supply device according to claim 1 , wherein the outer peripheral member applies a predetermined compressive stress to the power receiving side core.

7. The power supply device according to claim 2 , wherein the power transmitting section includes an annular recess that houses a coil, and a power transmitting core that includes an opening of the annular recess on the power receiving section side.

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