Winding field rotor

Abstract

In a rotor (60), a field winding (70) has a plurality of pole coils (110) wound around main pole sections (62). Each pole coil includes an outer coil (111) and an inner coil (112) that are adjacent to each other inside and outside in the radial direction. Insulating spacers (140) are provided between adjacent pole coils in the circumferential direction. Each spacer includes an outer portion (141), that is a site sandwiched between the outer coils of magnetic poles in the circumferential direction, and an inner portion (142), that is a site sandwiched between the inner coils of magnetic poles in the circumferential direction. A constricted section (143) where the width dimension in the circumferential direction is narrowed is provided at the boundary position between the outer coil and the inner coil in the radial direction. At least one axial end from among both axial ends of each spacer has a cross section in a direction orthogonal to the axial direction having a tapered shape that becomes smaller toward the pointed end side.

Description

Wound field rotor CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-059349, filed on April 2, 2024, the contents of which are incorporated herein by reference.

[0002] The disclosure herein relates to wound field rotors.

[0003] In a wound-field rotating electric machine, the rotor has a rotor core with multiple main poles (magnetic salient poles) arranged circumferentially and a field winding wound around the main poles. A technique has also been proposed for interposing spacers between the field windings of adjacent magnetic poles in the rotor. For example, Patent Document 1 (Patent Document 1) describes a winding structure in which the circumferential width of each main pole differs between the radially outer and inner sides. In this winding structure, a spacer provided between the windings of each magnetic pole is described, in which the circumferential width differs along the radial direction. This spacer configuration allows the windings of each magnetic pole to be fixed in position both circumferentially and radially.

[0004] International Publication No. 2021 / 094018

[0005] In the spacer having the above configuration, at least a portion of the spacer has a narrowed portion in the radial direction, which has a small width in the circumferential direction. In this case, during rotor manufacturing, the spacer is likely to be assembled by axial press-fitting into the gaps between the windings of each magnetic pole. However, if the spacer has a narrowed portion, there is a risk of the spacer being damaged due to stress concentration at the narrowed portion.

[0006] The present disclosure has been made in view of the above circumstances, and has an object to provide a wound field rotor in which spacers can be suitably interposed between the windings of each magnetic pole.

[0007] The present disclosure relates to a wound field rotor including: a rotor core having a plurality of main pole portions provided for each magnetic pole; and a field winding formed by winding a conductive wire multiple times in the radial and circumferential directions around each main pole portion, wherein the field winding has a plurality of pole coils wound around the main pole portion for each magnetic pole, the pole coils of each magnetic pole have an outer coil and an inner coil adjacent to each other in the radial direction, an insulating spacer is provided between the circumferentially adjacent pole coils, spanning the outer coil and the inner coil in the radial direction and in contact with the outer coil and the inner coil, the spacer has an outer portion that is a portion sandwiched between the outer coils of each magnetic pole in the circumferential direction, and an inner portion that is a portion sandwiched between the inner coils of each magnetic pole in the circumferential direction, and a constricted portion with a narrowed circumferential width is provided at a boundary position in the radial direction between the outer coil and the inner coil, At least one of the spacer's axial ends has a cross section perpendicular to the axial direction that tapers toward the tip.

[0008] In the wound field rotor having the above configuration, an insulating spacer is provided between the pole coils provided for each magnetic pole in the field winding. More specifically, the spacer is provided between circumferentially adjacent pole coils so as to straddle the outer coil and the inner coil in the radial direction. The spacer has an outer portion that is sandwiched between the outer coils of each magnetic pole and an inner portion that is sandwiched between the inner coils of each magnetic pole, and a constricted portion that narrows the circumferential width at the radial boundary between the outer coil and the inner coil. In this case, in the field winding, the outer coil and the inner coil are thermally connected by the spacer between the pole coils, but the constricted portion provided in the spacer suppresses heat transfer in the radial direction.

[0009] Furthermore, while the constricted portion of the spacer can suppress heat transfer between the radially inner and outer coils, in a configuration in which the spacer is provided between the pole coils in contact with the outer coil and the inner coil, there is a concern that the spacer may be damaged at the constricted portion when the spacer is inserted axially between the pole coils. In this regard, by tapering at least one of the axial ends of the spacer so that the cross section perpendicular to the axial direction becomes smaller toward the tip, stress when the spacer is inserted between the pole coils is reduced and damage to the spacer at the constricted portion can be suppressed. As a result, the spacer can be suitably interposed between the windings of each magnetic pole in the rotor.

[0010] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is an overall configuration diagram of a control system for a rotating electric machine, Fig. 2 is a diagram showing an inverter and its peripheral configuration, Fig. 3 is a cross-sectional view of a rotor and a stator, Fig. 4 is a diagram showing an electric circuit provided in the rotor, Fig. 5 is a perspective view showing the overall configuration of the rotor, Fig. 6 is a perspective view showing the rotor with a covering portion and a coil end cover removed, Fig. 7 is an exploded perspective view of the rotor, Fig. 8 is a longitudinal cross-sectional view of the rotor, Fig. 9 is a perspective view showing an exploded view of a winding unit in a rotor main portion, Fig. 10 is a cross-sectional view showing a partial cross-sectional structure of the rotor main portion, Fig. 11 is a cross-sectional view showing a partial cross-sectional structure of the rotor main portion, Fig. 12 is a diagram showing a specific winding structure of a conductor material in a coil module, and Fig. 13 is a cross-sectional view showing a state in which a spacer is assembled between the winding units. 14 is a cross-sectional view of the spacer, FIG. 15 is a perspective view of the spacer, FIG. 16 is a cross-sectional view showing the spacer assembled between the winding units, FIG. 17 is a front view showing an enlarged tip portion of the spacer, FIG. 18 is a schematic view showing the spacer assembled between the winding units, FIG. 19 is a cross-sectional view showing the spacer assembled between the winding units, FIG. 20 is a schematic view showing the spacer assembled between the winding units, FIG. 21 is a schematic view showing the spacer assembled between the winding units, FIG. 22 is a schematic view showing the spacer assembled between the winding units, FIG. 23 is a schematic view showing the spacer assembled between the winding units, and FIG. 24 is a schematic view showing the spacer assembled between the winding units.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A wound-field rotating electric machine according to an embodiment of the present disclosure is used as a power source for driving electric vehicles such as electric vehicles and hybrid vehicles.

[0012] First, a control system including a rotating electric machine will be described with reference to Fig. 1. The control system includes a DC power supply 10, an inverter 20, a control device 30, and a rotating electric machine 40. The rotating electric machine 40 is a self-excited wound field type synchronous machine. For example, the rotating electric machine 40, the inverter 20, and the control device 30 may be configured as an electromechanical integrated drive device, or the rotating electric machine 40, the inverter 20, and the control device 30 may each be configured as a separate component.

[0013] The rotating electric machine 40 includes a housing 41, and a stator 50 and a rotor 60 housed in the housing 41. The rotating electric machine 40 of this embodiment is an inner rotor type rotating electric machine in which the rotor 60 is disposed radially inside the stator 50.

[0014] The stator 50 includes a stator core 51 and a stator winding 52. The stator winding 52 is made of, for example, copper wire, and includes U-, V-, and W-phase windings 52U, 52V, and 52W that are arranged with an electrical angle offset of 120° from one another.

[0015] The rotor 60 includes a rotor core 61 and a field winding 70. The field winding 70 is preferably made of a conductor material such as aluminum wire, which has a low specific gravity and is easily formed. The conductor material of the field winding 70 is not limited to aluminum wire, and may be copper wire or CNT (carbon nanotube), for example. A rotating shaft 32 is attached to the center hole of the rotor core 61. The rotating shaft 32 is rotatably supported by bearings 42 and 43 in the housing 41.

[0016] As shown in FIG. 2 , the inverter 20 includes a series connection of upper-arm switches SUp, SVp, and SWp for U, V, and W phases and lower-arm switches SUn, SVn, and SWn for U, V, and W phases. First ends of U-, V-, and W-phase windings 52U, 52V, and 52W are connected to the connection points between the upper-arm switches SUp, SVp, and SWp and the lower-arm switches SUn, SVn, and SWn for each phase. Second ends of the U-, V-, and W-phase windings 52U, 52V, and 52W are connected at the neutral point. That is, in this embodiment, the stator winding 52 is star-connected. However, the stator winding 52 may also be delta-connected. In this embodiment, each of the switches SUp to SWn is, for example, an IGBT. A freewheel diode is connected in antiparallel to each of the switches SUp to SWn.

[0017] The collectors of the upper arm switches SUp, SVp, SWp of each phase are connected to the positive terminal of a DC power supply 10. The emitters of the lower arm switches SUn, SVn, SWn of each phase are connected to the negative terminal of the DC power supply 10. A smoothing capacitor 11 is connected in parallel to the DC power supply 10.

[0018] Next, the stator 50 and the rotor 60 will be described with reference to FIG.

[0019] The stator 50 and the rotor 60 are both arranged coaxially with the rotating shaft 32. In the following description, the direction in which the rotating shaft 32 extends is referred to as the axial direction, the direction extending radially from the center of the rotating shaft 32 is referred to as the radial direction, and the direction extending circumferentially around the rotating shaft 32 is referred to as the circumferential direction.

[0020] The stator core 51 is made of laminated steel plates made of a soft magnetic material and has an annular back yoke 51a and multiple teeth 51b protruding radially inward from the back yoke 51a. Multiple slots 54 are formed between adjacent teeth 51b in the circumferential direction. The stator winding 52 is formed by accommodating the phase windings of each phase in a predetermined order in each of these slots 54. For example, the stator 50 may employ a segment coil structure using multiple conductor segments. However, the structure of the stator winding 52 is arbitrary.

[0021] The rotor core 61 is made of a soft magnetic material, for example, laminated steel plates. The rotor core 61 has a cylindrical portion 61a and a plurality of main pole portions 62 that protrude radially outward from the cylindrical portion 61a. A field winding 70 is wound around the main pole portions 62 by concentrated winding. In this embodiment, eight main pole portions 62 are provided at equal intervals in the circumferential direction.

[0022] The field winding 70 includes a first winding portion 71 and a second winding portion 72. The first winding portion 71 is wound radially outward around each main pole portion 62, and the second winding portion 72 is wound radially inward relative to the first winding portion 71. In each main pole portion 62, the winding directions of the first winding portion 71 and the second winding portion 72 are the same. Furthermore, among circumferentially adjacent main pole portions 62, the winding direction of the winding portions 71, 72 wound around one is opposite to the winding direction of the winding portions 71, 72 wound around the other. Therefore, the magnetization directions of circumferentially adjacent main pole portions 62 are opposite to each other. In the rotor 60, the main pole portions 62 in the rotor core 61 and the field winding 70 wound around each main pole portion 62 form a plurality of magnetic poles (field poles) arranged circumferentially.

[0023] FIG. 4 is a diagram illustrating an electric circuit including the first and second winding portions 71 and 72 in the rotor 60. The first winding portion 71 and the second winding portion 72 are connected in series by connecting the second end 71b of the first winding portion 71 to the first end 72a of the second winding portion 72. A diode 91 and a capacitor 92 are connected to the second end 71b of the first winding portion 71 in parallel with the second winding portion 72. A diode 93 and a capacitor 94 are connected in series to the series connection of the first winding portion 71 and the second winding portion 72. In the following description, the diode 91 and the capacitor 92 connected in parallel with the second winding portion 72 are also referred to as the parallel diode 91 and the parallel capacitor 92, respectively. The diode 93 and the capacitor 94 connected in series with the series connection of the first winding portion 71 and the second winding portion 72 are also referred to as the series diode 93 and the series capacitor 94, respectively. The capacitors 92 and 94 are, for example, ceramic capacitors or film capacitors.

[0024] The parallel diode 91 has a cathode connected to the first end 72a of the second winding portion 72 and an anode connected to the second end 72b of the second winding portion 72. As a result, in a closed circuit including the second winding portion 72 and the parallel diode 91, current flows in one direction, from the anode side to the cathode side of the parallel diode 91. Furthermore, the series diode 93 has a cathode connected to the first end 71a of the first winding portion 71 and an anode connected to the second end 72b of the second winding portion 72. As a result, the field current flowing through each winding portion 71, 72 is rectified. In this embodiment, the number of turns of the second winding portion 72 is greater than the number of turns of the first winding portion 71.

[0025] Returning to the description of FIG. 2 , the control device 30 is an electronic control unit (EC) primarily composed of a microcomputer 31. The microcomputer 31 includes a central processing unit (CPU). The functions provided by the microcomputer 31 can be provided by software stored in a physical memory device and a computer executing the software, software alone, hardware alone, or a combination thereof. For example, if the microcomputer 31 is provided by a hardware electronic circuit, the functions can be provided by a digital circuit including multiple logic circuits or an analog circuit. For example, the microcomputer 31 executes a program stored in a non-transitory tangible storage medium (NSS) that serves as its own storage unit. The program includes a program for controlling the rotating electric machine 40. A method corresponding to the program is executed by executing a set of instructions that constitute the program. The storage unit is, for example, a non-volatile memory. The program stored in the storage unit can be updated via a communication network such as the Internet, for example, via OTA (Over the Air).

[0026] The control device 30 generates drive signals that turn on and off the switches SUp to SWn that configure the inverter 20. Specifically, the control device 30 generates drive signals that turn on and off the switches SUp to SWn and outputs the generated drive signals to the gates of the switches SUp to SWn in order to convert the DC power output from the DC power supply 10 into AC power and supply it to the U-, V-, and W-phase windings 52U, 52V, and 52W. As a result, the upper and lower arm switches in each phase are alternately turned on with dead times therebetween.

[0027] The control device 30 turns on and off the switches SUp to SWn so that a composite current of a fundamental current and a high-frequency current (specifically, a high-frequency excitation current) having a frequency higher than that of the fundamental current flows through each of the phase windings 52U, 52V, and 52W. The fundamental current is a current that mainly serves to generate torque in the rotary electric machine 40. The high-frequency current is a current that mainly serves to excite the first and second winding portions 71 and 72 that constitute the field winding 70, thereby inducing a field current in the field winding 70. The phase currents flowing through the phase windings 52U, 52V, and 52W are shifted by 120 electrical degrees.

[0028] The high-frequency current flowing through the stator winding 52 may be a harmonic current whose fluctuating frequency is N times (N is an integer of 2 or more) the frequency of the fundamental current, or may be a current whose fluctuating frequency is different from N times the frequency of the fundamental current.

[0029] When a high-frequency current flows through the stator winding 52, a voltage is induced in the first and second winding portions 71 and 72, causing a field current to flow. The induced voltages in the first and second winding portions 71 and 72 are, for example, in phase. The currents IL1 and IL2 flowing through the first and second winding portions 71 and 72 contain frequency components of the high-frequency current.

[0030] In the electric circuit shown in Fig. 4, when the first and second winding portions 71, 72 are excited by energizing the stator winding 52, a current flows from the first winding portion 71 to the second winding portion 72. Furthermore, when the voltage across the second winding portion 72 exceeds the forward voltage of the parallel diode 91, a current IL2, which is greater than the current IL1 flowing through the first winding portion 71, flows through the closed circuit including the second winding portion 72 and the parallel diode 91. The current flowing through the closed circuit including the second winding portion 72 and the parallel diode 91 increases the DC component of the field current. This increases the DC component of the magnetic flux of the rotor 60, thereby increasing the torque of the rotating electric machine 40.

[0031] Next, the configuration of the rotor 60 will be described in more detail. Fig. 5 is a perspective view showing the overall configuration of the rotor 60, and Fig. 6 is a perspective view showing the rotor 60 with the outer peripheral covering portion 102 that covers the rotor main portion 101 and the coil end covers 103, 104 removed. Fig. 7 is an exploded perspective view of the rotor 60, and Fig. 8 is a vertical cross-sectional view of the rotor 60.

[0032] The rotor 60 is broadly divided into a rotor main section 101, a cylindrical outer covering section 102 provided to surround the outer periphery of the rotor main section 101, coil end covers 103 and 104 attached to one and the other axial ends of the rotor main section 101, and a busbar module 105 and a circuit module 106 provided at one end of both axial sides of the rotor main section 101. The rotor main section 101 includes a rotor core 61 and a field winding 70, and the rotating shaft 32 is attached to the central hole of the rotor core 61. The field winding 70 is made up of a plurality of winding units 110 arranged in a row in the circumferential direction.

[0033] The busbar module 105 and the circuit module 106 are fixed to the rotating shaft 32 with the rotating shaft 32 inserted through each hollow portion, so that the busbar module 105 and the circuit module 106 are provided at positions axially facing the coil end portions of the field winding 70. The busbar module 105 has a plurality of bus bars for electrically connecting the winding units 110 for each magnetic pole.

[0034] The circuit module 106 includes a component holder 107 that houses electrical components, and a heat sink 108 that is placed over the component holder 107. The component holder 107 and the heat sink 108 are integrated with their axial end faces joined together. The component holder 107 holds diodes 91 and 93 and capacitors 92 and 94 as electrical components.

[0035] The heat sink 108 is fixed to one of the axial ends of the component holder 107, opposite the rotor core 61 (the right side in the figure). The heat sink 108 is made of, for example, aluminum. By fixing the heat sink 108 to the axial end face of the component holder 107, heat generated in the diodes 91 and 93 and the capacitors 92 and 94 when current is applied to the component holder 107 is released via the heat sink 108.

[0036] The outer covering portion 102 is formed by using, for example, a string-like yarn and winding the yarn in multiple layers around the outer periphery of the plurality of winding units 110 assembled to the rotor core 61 .

[0037] The configuration of the rotor main section 101 will be described using Figures 9 to 11. Figure 9 is an exploded perspective view of the winding units 110 in the rotor main section 101, and Figures 10 and 11 are cross-sectional views showing the cross-sectional structure of a portion of the rotor main section 101. Figure 10 shows the winding units 110 assembled to the rotor core 61, and Figure 11 shows one of the winding units 110 disassembled. Note that Figure 10 depicts the outer circumferential covering portion 102 shown in Figure 5 as a structure for holding the field winding 70 wound around the main pole portion 62 of the rotor core 61.

[0038] The rotor main section 101 has a plurality of winding units 110, one for each magnetic pole of the rotor 60. Each winding unit 110 is formed in an annular shape with its longitudinal direction in the axial direction, and is assembled to the rotor core 61 with the main pole section 62 inserted through its hollow section.

[0039] The winding unit 110 has a first coil module 111 that is located radially outward when attached to the main pole section 62, and a second coil module 112 that is located radially inward. The first coil module 111 is a coil module that corresponds to the first winding section 71, and the second coil module 112 is a coil module that corresponds to the second winding section 72. In this embodiment, the winding unit 110 forms a pole coil. The first coil module 111 and the second coil module 112 are adjacent to each other radially inward and outward, with the first coil module 111 corresponding to an outer coil and the second coil module 112 corresponding to an inner coil.

[0040] The first coil module 111 includes a coil body 121 formed by multiple windings of conductive wire and an insulator 122 that provides an insulating coating around the coil body 121. The coil body 121 is an air-core coil formed by multiple windings of conductive wire in the radial and circumferential directions. The insulator 122 is molded from an insulating material such as resin and includes a coating portion 123 that extends along the inner circumferential surface of the coil body 121 and serves as an insulating coating for the main pole portion 62, and a coating portion 124 that extends along both sides of the coil body 121 in the thickness direction and serves as a radial insulating coating. The insulator 122 may be composed of two members that can be separated in the thickness direction (i.e., radial direction) of the coil body 121. For example, as shown in the figure, the insulator 122 may be composed of an outer coating portion on the radially outer side and an inner coating portion on the radially inner side.

[0041] In the insulator 122, the covering portion 123 corresponds to a radial covering portion that extends radially between the main pole portion 62 and the coil body 121. The covering portions 124 are provided on the radially inner and outer sides, and here, the covering portion 124 on the radially inner side is referred to as an inner covering portion 124a, and the covering portion 124 on the radially outer side is referred to as an outer covering portion 124b.

[0042] The second coil module 112 also includes a coil body 131 formed by multiple windings of conductive wire and an insulator 132 that provides an insulating coating around the coil body 131. The coil body 131 is an air-core coil formed by multiple windings of conductive wire in the radial and circumferential directions. The insulator 132 is molded from an insulating material such as resin and includes a coating portion 133 that extends along the inner circumferential surface of the coil body 131 and serves as an insulating coating for the main pole 62, and a coating portion 134 that extends along both sides of the coil body 131 in the thickness direction and serves as a radial insulating coating. The insulator 132 may be composed of two members that can be separated in the thickness direction (i.e., radial direction) of the coil body 131. For example, as shown in the figure, the insulator 132 may be composed of an outer coating portion on the radially outer side and an inner coating portion on the radially inner side.

[0043] In the insulator 132, the covering portion 133 corresponds to a radial covering portion that extends radially between the main pole portion 62 and the coil body 131. The covering portions 134 are provided on the radially inner and outer sides, and here, the covering portion 123 on the radially inner side is an inner covering portion 134a, and the covering portion 134 on the radially outer side is an outer covering portion 134b.

[0044] The first coil module 111 and the second coil module 112 are arranged radially side by side with their respective insulators 122, 132 abutting against each other, more specifically, with the inner covering portion 124a of the insulator 122 and the outer covering portion 134b of the insulator 132 abutting against each other.

[0045] The inner covering portion 124a of the insulator 122 and the outer covering portion 134b of the insulator 132 correspond to an "insulating member" that insulates the coil bodies 121, 131 of the coil modules 111, 112 arranged radially inside and outside each other between the coil modules 111, 112. Note that only one of the inner covering portion 124a of the insulator 122 and the outer covering portion 134b of the insulator 132 may be interposed between the coil modules 111, 112.

[0046] 9, two conductor wire ends 125 are drawn out in the axial direction in the first coil module 111, and two conductor wire ends 135 are drawn out in the axial direction in the second coil module 112. In each of the winding units 110 arranged in the circumferential direction, the conductor wire ends 125, 135 are connected to each other, so that the multiple first coil modules 111 provided on each main pole portion 62 are connected in series, and the multiple second coil modules 112 provided on each main pole portion 62 are connected in series.

[0047] FIG. 12 shows the specific winding structure of the conductor wire in each coil module 111, 112. The coil body 121 of the first coil module 111 is, for example, an α-winding coil in which the conductor wire is wound in an α-winding pattern. The coil body 131 of the second coil module 112 is a continuous-winding coil in which the conductor wire is continuously wound in a predetermined circumferential direction. The conductor wire used in the coil bodies 121, 131 is, for example, a flat wire having a substantially rectangular cross-section (specifically, a substantially rectangular shape). The flat wire consists of a conductor portion made of aluminum or the like and an insulating layer covering the conductor portion. However, round wire having a circular cross-section can also be used as the conductor wire. The coil structure in each coil module 111, 112 is not limited; for example, the coil bodies 121, 131 can both be continuous-winding coils.

[0048] 12 , the first coil module 111 has two radially wound layers of conductor wire, while the second coil module 112 has twelve radially wound layers. Each of the coil modules 111, 112 may have any number of layers, but it is preferable that the number of layers in the second coil module 112 is greater than the number of layers in the first coil module 111. The coil modules 111, 112 have different numbers of circumferential turns (i.e., the number of rows of conductor wire in the circumferential direction), with the number of turns being greater on the radially outer side than on the radially inner side. This improves the space factor of the field winding 70.

[0049] In the rotor core 61, the spaces between the main poles 62 arranged in the circumferential direction are gaps (slots) extending in the axial direction, and the field windings 70 of each magnetic pole are wound using these gaps. In this case, the gaps between the main poles 62 in the circumferential direction house one coil side portion between the coil end portions on both axial sides of the winding units 110 of two circumferentially adjacent magnetic poles.

[0050] In this embodiment, the rotor 60 is configured such that insulating spacers 140 are provided between circumferentially adjacent winding units 110, and the configuration of the spacers 140 will be described below. Fig. 13 is a cross-sectional view showing the state in which the spacers 140 are assembled between the winding units 110 in the rotor main section 101, and Fig. 14 is a cross-sectional view of the spacer 140. Fig. 15 is a perspective view of the spacer 140.

[0051] The spacer 140 is provided between circumferentially adjacent winding units 110, straddling the first coil module 111 and the second coil module 112 on the inner and outer radial sides, and in contact with each of these coil modules 111, 112. The spacer 140 is molded from, for example, a resin material serving as an insulating material.

[0052] 13 and 14 , the spacer 140 has an outer portion 141 that is a portion sandwiched between circumferentially adjacent first coil modules 111, and an inner portion 142 that is a portion sandwiched between circumferentially adjacent second coil modules 112. The spacer 140 also has a constricted portion 143 that has a narrowed circumferential width at the boundary position between the first coil module 111 and the second coil module 112 in the radial direction.

[0053] More specifically, in each coil module 111, 112, rectangular conductor wire is wound multiple times in the radial and circumferential directions, and the number of turns of the conductor wire differs between the inside and outside of the radial direction, resulting in a stepped circumferential side surface (coil side surface) of each coil module 111, 112. On the other hand, both circumferential surfaces of the spacer 140, i.e., the surfaces facing each circumferentially adjacent coil module 111, 112, are uneven surfaces with radially aligned irregularities. In other words, both circumferential surfaces of the spacer 140 are formed in a triangular wave shape (sawtooth shape) to match the stepped shape of the circumferential side surfaces of each coil module 111, 112. The irregularities on both circumferential surfaces of the spacer 140 are formed in the form of multiple linear stripes extending in the axial direction (see FIG. 15 ).

[0054] In this case, spacers 140 are attached between the circumferentially adjacent winding units 110, thereby filling the gaps between the circumferentially adjacent winding units 110. This prevents misalignment and collapse of the conductor wire in each of the coil modules 111, 112.

[0055] The spacer 140 has a plurality of recesses arranged radially on both circumferential surfaces, and the recesses at the boundary positions between the radially adjacent first coil module 111 and second coil module 112 form constricted portions 143. In the spacer 140, each of the recesses including the constricted portions 143 is a portion where the width dimension in the circumferential direction is narrowed. In the spacer 140, the recesses among the plurality of recesses excluding the constricted portions 143 are provided for each row or for each plurality of rows of the conductor material in the radial direction.

[0056] In each coil module 111, 112, the tip ends of the covering portions 124a, 134b that extend circumferentially and abut against each other in the insulators 122, 132, i.e., the tip ends on the opposite side of the main pole portion 62 in the circumferential direction, protrude circumferentially beyond the conductor material of each coil body 121, 131. Furthermore, the tip ends of the covering portions 124a, 134b between circumferentially adjacent winding units 110 are spaced apart from each other. A spacer 140 is assembled between circumferentially adjacent winding units 110 such that the tip ends of the covering portions 124a, 134b of each insulator 122, 132 fit into a constricted portion 143 of the spacer 140. The spacer 140 is assembled in contact with each coil module 111, 112 and inserted between the winding units 110 by, for example, press-fitting.

[0057] The rotor 60 may simply have the configuration shown in Fig. 16. In Fig. 16, the spacer 140 has an outer portion 141 that is a portion sandwiched between the first coil modules 111 of each magnetic pole in the circumferential direction, and an inner portion 142 that is a portion sandwiched between the second coil modules 112 of each magnetic pole in the circumferential direction, and a constricted portion 143 is provided at the boundary between the coil modules 111, 112 in the radial direction. In other words, the spacer 140 may have a constricted portion 143 provided at least at the boundary between the coil modules 111, 112 in the radial direction. The circumferential tip ends of the covering portions 124a, 134b of the insulators 122, 132 are configured to fit into the constricted portion 143 of the spacer 140.

[0058] According to the configurations shown in Figures 13 and 16, in the field winding 70, the first coil module 111, which is the outer coil, and the second coil module 112, which is the inner coil, are thermally connected by the spacer 140, but the constricted portion 143 provided in the spacer 140 suppresses heat transfer in the radial direction.

[0059] During manufacture of the rotor 60, after the field winding 70 is assembled to the rotor core 61, the spacers 140 are assembled axially between the circumferentially adjacent winding units 110. In this case, for example, when the spacers 140 are inserted between the winding units 110 by press-fitting, there is a concern that the spacers 140 may be damaged at the constricted portions 143. Therefore, in this embodiment, in order to reduce stress when inserting the spacer, at least one of the axial ends of the spacer 140 is formed into a tapered shape in which the cross section perpendicular to the axial direction becomes smaller toward the tip.

[0060] 17 is an enlarged front view of the tip portion of the spacer 140. If the cross-section of the spacer 140 perpendicular to the axial direction (the cross-sectional area when sheared in the axial direction) is S, the cross-sectional areas S1, S2, and S3 at three different axial positions P1, P2, and P3 satisfy the relationship S1 > S2 > S3. In this case, position P1 is a non-tapered position, and positions P2 and P3 are tapered positions at the ends of the spacer. Of positions P2 and P3, position P3 is closer to the tip than position P2, and the cross-section becomes smaller as it approaches the tip. Position P1 is a position that corresponds to the coil side portion of the spacer 140, and positions P2 and P3 are positions that correspond to the coil end portions.

[0061] The axial end faces of the spacer 140 are formed in a straight line oblique to the axial direction. In other words, the axial end faces of the spacer 140 have a shape with no steps when viewed from the front. This prevents localized stress concentration on the tip faces of the spacer when the spacer 140 is inserted between the winding units 110 with the axial end of the spacer 140 at the front.

[0062] Figure 18 is a schematic diagram showing a state in which a spacer 140 is being assembled into a gap between winding units 110 in the rotor main section 101. When viewed from the front, the spacer 140 has a tapered shape on both axial sides, and is inserted between the winding units 110 from its tapered axial tip. The left side of Figure 18 shows the spacer 140 after insertion.

[0063] The spacer 140 has a portion A1 that overlaps the rotor core 61 in the radial direction and a portion A2 that protrudes axially from the rotor core 61, and the portion A2 of the spacer 140 that protrudes from the rotor core 61 has a height that is higher on the radially outer side from the axial end face of the rotor core 61 and lower on the radially inner side. In other words, since the field winding 70 has a greater number of turns of wire on the radially outer side than on the radially inner side, the coil end (rotor coil end) of the field winding 70 is higher on the radially outer side from the rotor core 61 than on the radially inner side. And, like the rotor coil end, the axial tip end of the spacer 140 also has a higher axial height on the radially outer side.

[0064] In this case, spacers 140 are interposed between circumferentially adjacent winding units 110, both in the coil side portions that overlap with the rotor core 61 in the axial direction and in the coil end portions that are axially outward of the rotor core 61. This reduces stress when inserting the spacers, while also preventing misalignment and collapse of the winding material at the coil ends of the winding units 110.

[0065] Note that only one of the axial ends of the spacer 140 may be tapered. In this case, it is preferable that the axial end that becomes the leading end when inserted between the winding units 110 is tapered.

[0066] 13 and 16 , in each winding unit 110, the circumferential leading ends of the covering portions 124 a, 134 b of the insulators 122, 132 protrude beyond the conductor wire of each coil body 121, 131 and fit into the constricted portion 143 of the spacer 140. In this case, when the spacer 140 is inserted into the circumferential gap between the winding units 110, the circumferential leading ends of the covering portions 124 a, 134 b act as guides that guide the spacer 140 in the axial direction. This makes it easy to insert the spacer between the winding units 110.

[0067] As shown in Fig. 19, the spacer 140 may have a configuration in which the constricted portion 143 does not contact the circumferential leading ends of the covering portions 124, 134 of the insulators 122, 132. Specifically, in the spacer 140 shown in Fig. 19, the circumferential width dimension of the constricted portion 143 is smaller than that of the spacer 140 shown in Fig. 13. That is, in the spacer 140 shown in Fig. 19, the degree of constriction of the constricted portion 143 is greater. In this case, direct application of stress from the covering portions 124a, 134b to the constricted portion 143 of the spacer 140 is suppressed. This suppresses damage to the constricted portion 143.

[0068] 12 and 13 , in each of the coil modules 111 and 112, the coil side surface is stepped in the radial direction due to the difference in the number of turns of the conductor wire on the radial inside and outside. That is, a step (conductor step) is formed on the circumferential side surface of each of the coil modules 111 and 112. Meanwhile, as shown in FIGS. 13 and 14 , the spacer 140 has a first opposing portion 144 that faces the stepped coil side surface from the radial inside on the radial outside and the radial inside of the constricted portion 143, i.e., the outer portion 141 and the inner portion 142, respectively.

[0069] In this case, when centrifugal force acts on each winding unit 110 and spacer 140 during rotation of rotor 60, a load is applied to constricted portion 143 of spacer 140. However, because first opposing portion 144 and second opposing portion 145 face the stepped coil side surfaces on both the radially outer and inner sides of constricted portion 143, excessive force is prevented from being applied to constricted portion 143. This allows spacer 140 to be properly protected.

[0070] 13 , in the spacer 140, the first opposing portions 144 are preferably parallel to the circumferential side surfaces (specifically, the outer circumferential surfaces of the conductors) of the coil modules 111, 112. The second opposing portions 145 are preferably parallel to the circumferential side surfaces (specifically, the outer circumferential surfaces of the conductors) of the coil modules 111, 112. This configuration makes it easy to insert the spacer 140 between the winding units 110.

[0071] Here, if the radial thickness dimensions of the first coil module 111 on the radially outer side and the second coil module 112 on the radially inner side in the winding unit 110 are different from each other, the boundary position between these coil modules 111, 112 will be shifted from the center position in the thickness direction (radial center position) of the winding unit 110. In this case, in consideration of protecting the constricted portion 143 that forms the boundary between the coil modules 111, 112 in the spacer 140, when inserting the spacer 140 axially between circumferentially adjacent winding units 110, it is desirable to insert the side closer to the constricted portion 143 into the gap between the units first.

[0072] 18, the radial thickness of the radially outer first coil module 111 is smaller than the radial thickness of the radially inner second coil module 112, and the spacer 140 has a shape such that the radially outer radial end, i.e., the radial end on the first coil module 111 side, at the axial end that is the insertion tip side, is tapered to a tip. This makes it possible to prevent damage to the constricted portion 143 when the spacer is inserted.

[0073] As described above in detail, in the rotor 60, the spacers 140 are provided between the circumferentially adjacent winding units 110, and the spacers 140 suppress radial heat transfer at the constricted portions 143. However, on the other hand, there is a concern that the spacers 140 may be damaged at the constricted portions 143 when the spacers 140 are inserted axially between the winding units 110. In this regard, the axial end portions of the spacers 140 are tapered so that the cross section perpendicular to the axial direction becomes smaller toward the tip. This reduces stress when the spacer is inserted between the winding units 110, and thus suppresses damage to the spacers 140 at the constricted portions 143. As a result, the spacers 140 can be suitably interposed between the windings of each magnetic pole in the rotor 60.

[0074] (Other Embodiments) The above embodiment may be modified as follows, for example.

[0075] The spacer 140 may have the configuration shown in Fig. 20. In Fig. 20, as described above, the field winding 70 has a greater number of turns of wire material on the radially outer side than on the radially inner side, and the rotor coil ends have a higher coil end height on the radially outer side than on the radially inner side.

[0076] On the other hand, the spacer 140 has a portion A1 that overlaps the rotor core 61 in the radial direction and a portion A2 that protrudes axially from the rotor core 61, and the height of the portion A2 of the spacer 140 that protrudes from the rotor core 61 from the axial end face of the rotor core 61 is greatest at the radial midpoint and gradually decreases on both sides in the radial direction. In this case, in the rotor 60, the spacer 140 is interposed in part between the winding units 110 at the coil ends of the field winding 70, and the space not interposed by the spacer 140 can be used as a circulation path for the refrigerant.

[0077] 20 , a coil end cover 104 is attached to the rotating shaft 32 so as to cover the coil ends of the field winding 70, and a through hole 104a is provided in the coil end cover 104 in the axial direction. A refrigerant is supplied to the coil end cover 104 from the axial direction, and the refrigerant passes through the through hole 104a and reaches the coil ends of the field winding 70. The coil ends of the field winding 70 are then cooled by the refrigerant. In this case, a refrigerant flow path is secured between circumferentially adjacent winding units 110 on the radially outer side where the rotor coil ends are higher. This provides a configuration that is suitable for cooling the field winding 70.

[0078] 21 , the spacer 140 may be configured to have a height in the axial direction greater than that of the coil end of the field winding 70 (a height dimension from the end face of the rotor core greater than that of the rotor coil end). In this case, the spacer 140 may be configured such that the axial height at one end of the spacer 140 is greater than that of the coil end of the field winding 70, and the axial height at the other end of the spacer 140 is smaller than that of the coil end of the field winding 70.

[0079] The spacer 140 may be configured as two spacer pieces divided in the axial direction. A specific configuration thereof will be described below.

[0080] 22, the spacer 140 is divided in the axial direction and consists of two spacer pieces 151, 152. In each of the spacer pieces 151, 152, the axial end portion closest to the axial center of the rotor core 61, i.e., the axial end portion closest to the axial center, is the leading portion when inserted into the gap between the winding units 110, and has a tapered shape in which the cross section perpendicular to the axial direction becomes smaller toward the tip.

[0081] In this case, the axial length of each spacer piece 151, 152 is shorter than when the spacer 140 is not divided in the axial direction. Also, because each spacer piece 151, 152 can be inserted from one axial end side and the other axial end side, the amount of insertion required when inserting into the gap between the winding units 110 is halved. This makes it possible to effectively prevent damage to the spacer 140.

[0082] 23 , the axial center ends of the spacer pieces 151, 152 are preferably joined to each other with a bonding material 153 and also to the winding units 110 with the bonding material 153. In this case, it is possible to prevent the spacer 140 from shifting in the axial direction in the gaps between the winding units 110. Furthermore, because the spacer pieces 151, 152 are joined to the winding units 110 at the axial center of the winding units 110, the bonding material 153 is prevented from protruding beyond the axial ends of the field winding 70.

[0083] 24, the radial thickness of the radially inner second coil module 112 is smaller than the radial thickness of the radially outer first coil module 111. Each spacer piece 151, 152 is inserted from both axial sides, and the radially inner radial end, i.e., the radial end on the second coil module 112 side, at the axial end that is the insertion tip side, is shaped to taper to a tip. This makes it possible to suitably prevent damage to the constricted portion 143 when each spacer piece 151, 152 is inserted.

[0084] In the stator 50, the stator core may not be provided with teeth.

[0085] The rotating electric machine is not limited to a rotating electric machine used as an in-vehicle main engine, but may be, for example, a rotating electric machine used as an ISG (Integrated Starter Generator) that is both a motor and a generator.

[0086] The moving body on which the rotating electric machine system is mounted is not limited to a vehicle, but may be, for example, an aircraft or a ship. Furthermore, the rotating electric machine system is not limited to a system mounted on a moving body, but may be a stationary system.

[0087] The technical concepts extracted from the above-described embodiments are described below. [Configuration 1] A wound field rotor (60) including: a rotor core (61) having a plurality of main pole portions (62) provided for each magnetic pole; and a field winding (70) formed by multiple windings of conductive wire around each main pole portion in the radial and circumferential directions, wherein the field winding has a plurality of pole coils (110) wound around the main pole portion for each magnetic pole, and the pole coil of each magnetic pole has an outer coil (111) and an inner coil (112) adjacent to each other in the radial direction, and an insulating spacer (140) is provided between the circumferentially adjacent pole coils, straddling the outer coil and the inner coil in the radial direction and in contact with the outer coil and the inner coil, the spacer has an outer portion (141) that is a portion that is sandwiched between the outer coils of each magnetic pole in the circumferential direction, and an inner portion (142) that is a portion that is sandwiched between the inner coils of each magnetic pole in the circumferential direction, and a constricted portion (143) that has a narrowed circumferential width is provided at the boundary position between the outer coil and the inner coil in the radial direction, and at least one of the axial ends of the spacer has a tapered shape in which a cross section perpendicular to the axial direction becomes smaller toward the tip. [Configuration 2] A wound field rotor according to Configuration 1, wherein the field winding has a greater number of turns of wire on the radially outer side than on the radially inner side, and the coil ends of the field winding have a higher coil end height from the rotor core on the radially outer side than on the radially inner side, and the spacer has a portion that radially overlaps the rotor core and a portion that protrudes from the rotor core in the axial direction, and the portion of the spacer that protrudes from the rotor core has a higher height from the axial end face of the rotor core on the radially outer side and a lower height on the radially inner side.[Configuration 3] The wound field rotor according to Configuration 1, wherein the field winding has a greater number of turns of wire on the radially outer side than on the radially inner side, and the coil ends of the field winding have a higher coil end height from the rotor core on the radially outer side than on the radially inner side, the spacer has a portion that radially overlaps the rotor core and a portion that protrudes from the rotor core in the axial direction, and the portion of the spacer that protrudes from the rotor core has a height from the axial end face of the rotor core that is highest at a radial midpoint and gradually decreases on both radial sides. [Configuration 4] The wound field rotor according to any of Configurations 1 to 3, wherein the insulating member (124a, 134b) is provided for each main pole portion, extends circumferentially between the outer coil and the inner coil, and insulates the outer coil and the inner coil from each other, and the tip end of the insulating member of each magnetic pole on the opposite side to the main pole portion in the circumferential direction protrudes circumferentially beyond the wire of the pole coil and is within the constricted portion of the spacer. [Configuration 5] The wound field rotor according to Configuration 4, wherein in the spacer, the constricted portion does not contact a circumferential tip end portion of the insulating member. [Configuration 6] The wound field rotor according to any of Configurations 1 to 5, wherein the outer coil and the inner coil each have a larger number of turns of wire material on the radially outer side than on the radially inner side, and the circumferential side surfaces of the outer coil and the inner coil are stepped in the radial direction, and the spacer has, at the outer portion and the inner portion, a first opposing portion (144) that faces the stepped coil side surface from the radially inner side and a second opposing portion (144) that faces the stepped coil side surface from the radially outer side, respectively. [Configuration 7] A wound field rotor according to any one of configurations 1 to 6, wherein the outer coil and the inner coil have different radial thickness dimensions, and the axial end of the spacer, which becomes the insertion tip side when the spacer is inserted axially between the circumferentially adjacent pole coils, has a shape such that the radial end of the outer coil or the inner coil which has a smaller radial thickness dimension becomes a tapered tip.[Configuration 8] The wound field rotor according to any one of Configurations 1 to 7, wherein the spacer is made up of two spacer pieces (151, 152) divided in the axial direction, and each of the spacer pieces has an axial end portion located on the axial center side, which has a tapered shape such that a cross section perpendicular to the axial direction becomes smaller toward the tip. [Configuration 9] The wound field rotor according to Configuration 8, wherein the axial end portions located on the axial center side of each of the spacer pieces are joined to each other and to the pole coils by a joining material.

[0088] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A wound field rotor (60) comprising: a rotor core (61) having a plurality of main pole portions (62) provided for each magnetic pole; and a field winding (70) formed by multiple radial and circumferential windings of conductive wire around each of the main pole portions, wherein the field winding has a plurality of pole coils (110) wound around the main pole portion for each magnetic pole, and the pole coil of each magnetic pole has an outer coil (111) and an inner coil (112) adjacent to each other in the radial direction, and an insulating spacer (140) is provided between the circumferentially adjacent pole coils, straddling the outer coil and the inner coil in the radial direction and in contact with the outer coil and the inner coil, the spacer has an outer portion (141) that is a portion that is sandwiched between the outer coils of each magnetic pole in the circumferential direction, and an inner portion (142) that is a portion that is sandwiched between the inner coils of each magnetic pole in the circumferential direction, and a constricted portion (143) that has a narrowed circumferential width is provided at the boundary position between the outer coil and the inner coil in the radial direction, and at least one of the axial ends of the spacer has a tapered shape in which a cross section perpendicular to the axial direction becomes smaller toward the tip.

2. A wound field rotor as claimed in claim 1, wherein the field winding has a greater number of turns of wire on the radially outer side than on the radially inner side, and the coil ends of the field winding are higher from the rotor core on the radially outer side than on the radially inner side, and the spacer has a portion that overlaps the rotor core in the radial direction and a portion that protrudes from the rotor core in the axial direction, and the portion of the spacer that protrudes from the rotor core has a higher height from the axial end face of the rotor core on the radially outer side and a lower height on the radially inner side.

3. A wound field rotor as claimed in claim 1, wherein the field winding has a greater number of turns of wire on the radially outer side than on the radially inner side, and the coil ends of the field winding are higher from the rotor core on the radially outer side than on the radially inner side, and the spacer has a portion that overlaps the rotor core in the radial direction and a portion that protrudes from the rotor core in the axial direction, and the portion of the spacer that protrudes from the rotor core has a height from the axial end face of the rotor core that is greatest at the radial midpoint and gradually decreases on both radial sides.

4. A wound field rotor according to any one of claims 1 to 3, further comprising an insulating member (124a, 134b) provided for each of the main pole portions, extending circumferentially between the outer coil and the inner coil to insulate the outer coil and the inner coil from each other, wherein the tip of the insulating member for each magnetic pole on the opposite side to the main pole portion in the circumferential direction protrudes circumferentially beyond the conductor material of the pole coil and is within the constricted portion of the spacer.

5. A wound field rotor according to claim 4, wherein the constricted portion of the spacer does not contact the circumferential tip of the insulating member.

6. A wound field rotor according to any one of claims 1 to 3, wherein the outer coil and the inner coil each have a greater number of turns of wire material on the radially outer side than on the radially inner side, and the circumferential side surfaces of the outer coil and the inner coil are stepped in the radial direction, and the spacer has, at the outer and inner parts, a first opposing portion (144) that faces the stepped coil side surface from the radially inner side and a second opposing portion (144) that faces the stepped coil side surface from the radially outer side, respectively.

7. A wound field rotor according to any one of claims 1 to 3, wherein the outer coil and the inner coil have different radial thickness dimensions, and the axial end of the spacer, which becomes the leading end when the spacer is inserted axially between circumferentially adjacent pole coils, has a shape such that the radial end of the outer coil or the inner coil which has the smaller radial thickness dimension becomes a tapered tip.

8. A wound field rotor according to any one of claims 1 to 3, wherein the spacer is made up of two spacer pieces (151, 152) divided in the axial direction, and each of the spacer pieces has an axial end portion, which is located toward the axial center, tapered so that the cross section perpendicular to the axial direction becomes smaller toward the tip.

9. A wound field rotor according to claim 8, wherein the axial ends of each of the spacer pieces, which are located on the axial center side, are joined to each other with a joining material and are joined to the pole coil.

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