Winding field magnet rotor

Abstract

To provide a winding filed magnet rotor that can appropriately hold a field magnet winding through assembly of a ring-shaped member and ensure the performance of a rotary electric machine.SOLUTION: A rotor comprises: a rotor core that has a plurality of main pole parts arranged side by side in a circumferential direction; field magnet windings provided circling around the main pole parts; and a metallic ring-shaped member provided to enclose the main pole parts and the field magnet windings from the radial outside. When the pulling strength of the ring-shaped member of the rotor is defined as Ts (MPa) and the magnetic flux density at a magnetizing force of 5000 A / m as B50 (T), the ring-shaped member satisfies the relationship of Ts≥920*B50^2-2520*B50+2000 with B50<0.9, and satisfies the relationship of Ts≥230*B50^2-680*B50+900 with B50≥0.9.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The disclosure herein relates to wound field rotors. [Background technology]

[0002] A wound-field rotating electric machine has a stator with a stator winding and a rotor with a field winding. The rotor has a rotor core with a plurality of main poles (magnetic salient poles), and the field winding is wound around the main poles. Patent Document 1 also discloses a rotor structure in which the rotor is provided with a circular member formed by spirally winding a metal wire around the rotor core and the outer periphery of the field winding. With this rotor structure, even if centrifugal force acts on the field winding when the rotor rotates, the wire wound around the field winding prevents the field winding from shifting in position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-9553 Summary of the Invention [Problem to be solved by the invention]

[0004] The tensile strength and magnetic flux density of the circular member assembled to the outer periphery of the rotor core and the field winding vary depending on the material used. For example, if the tensile strength of the circular member is low, the circular member must be thicker to ensure the strength to hold the field winding in the rotor, which increases the radial gap between the rotor and the stator. Therefore, to ensure the desired motor performance, a material with a high magnetic flux density must be selected. Furthermore, if the circular member is made excessively thick even though the field winding has sufficient strength to hold it, it is likely that motor performance will be unnecessarily reduced. In this regard, to properly hold the field winding by assembling the circular member and ensure the performance of the rotating electric machine, it is desirable to properly specify the tensile strength and magnetic flux density of the circular member.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a wound field rotor that can properly hold a field winding by assembling a circular member and ensure the performance of a rotating electric machine. [Means for solving the problem]

[0006] The wound field rotor of the present disclosure has: a rotor core having a plurality of main pole portions provided for magnetic poles aligned in the circumferential direction; a field winding provided around each of the main pole portions; and a metal annular member provided so as to surround the main pole portions and the field winding from the radially outer side.

[0007] If the rotor's circular member has a tensile strength of Ts [MPa] and a magnetic flux density of B50 [T] when the magnetizing force is 5000 A / m, then: When B50<0.9, Ts≧920*B50^2-2520*B50+2000 Satisfying the relationship, When B50≧0.9, Ts≧230*B50^2-680*B50+900 The relationship between the magnetic flux density and the magnetic flux density is assumed to be satisfied.

[0008] In a wound field rotor, centrifugal force is applied to the field winding during rotation, so the annular member surrounding the field winding must be strong enough to withstand that centrifugal force. From the perspective of the performance of the rotating electric machine, it is desirable to increase the magnetic flux density in the gap between the rotor and the stator, and it is therefore desirable to construct the annular member from a magnetic material. In light of this, in order to satisfy the strength requirements of the field winding and the performance requirements of the rotating electric machine, the tensile strength Ts of the annular member and the magnetic flux density B50 are set to satisfy the above-mentioned relationship.

[0009] This relationship specifies, for example, the relationship shown in Figure 12. That is, when a material with a relatively low magnetic flux density B50 is used, the thickness of the annular member is subject to significant restrictions. However, this specification specifically specifies the use of a material with a high tensile strength Ts so that sufficient strength can be achieved even with a small thickness of the annular member. On the other hand, when a material with a relatively high magnetic flux density B50 is used, the thickness of the annular member can be increased, so this specification specifically specifies that a material with a low tensile strength Ts can be used. This makes it possible for the annular member to satisfy both the strength requirements and the magnetic flux density requirements. As a result, the field winding can be properly held by assembling the annular member, and the performance of the rotating electric machine can be ensured.

[0010] Or, if the tensile strength of the rotor's circular member is Ts [MPa] and the magnetic flux density when the magnetizing force is 5000 A / m is B50 [T], When B50<0.75, Ts≧-1540*B50+2000 Satisfying the relationship, When B50≧0.75, Ts≧150*B50^2-500*B50+1140 The relationship between the above is to be satisfied.

[0011] The above relationship defines, for example, the relationship shown in Figure 16. Even with a configuration using this relationship, it is possible to satisfy both the strength requirements and the magnetic flux density requirements for the annular member, as in the above. As a result, the field winding can be properly held by assembling the annular member, and the performance of the rotating electric machine can be ensured.

[0012] Furthermore, in each of the above relationships between the tensile strength Ts and the magnetic flux density B50 of the annular member, the relationship differs between a region where the magnetic flux density B50 is relatively low and a region where the magnetic flux density B50 is relatively high, and so the relationship between the tensile strength Ts and the magnetic flux density B50 is varied depending on the magnetic flux density B50. This allows the use of metal materials suitable for the annular member over a wide range of magnetic flux densities B50. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is an overall configuration diagram of a control system for a rotating electrical machine. [Figure 2] FIG. 2 is a diagram showing an inverter and its peripheral configuration. [Figure 3] FIG. [Figure 4] FIG. 3 is a diagram showing an electric circuit provided in the rotor. [Figure 5] FIG. 2 is a perspective view showing the overall configuration of the rotor. [Figure 6] FIG. 4 is a perspective view showing a state in which the annular member and the coil end cover are removed from the rotor. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. 3 is an exploded perspective view of a winding unit in the rotor main portion. [Figure 10] FIG. 3 is a cross-sectional view showing a cross-sectional structure of a part of a rotor main portion. [Figure 11] FIG. [Figure 12] FIG. 10 is a graph showing the relationship between magnetic flux density B50 and tensile strength Ts for a circular member. [Figure 13]FIG. 10 is a diagram showing numerical values ​​of analysis data obtained by electromagnetic field analysis software. [Figure 14] FIG. 10 is a diagram showing the relationship between ring thickness and rotating electrical machine torque for a plurality of materials with different magnetic flux densities B50. [Figure 15] FIG. 10 is a diagram showing the relationship between magnetic flux density B50 and ring thickness when the same predetermined torque is realized in a rotating electric machine. [Figure 16] FIG. 10 is a graph showing the relationship between magnetic flux density B50 and tensile strength Ts for a circular member. [Figure 17] FIG. 10 is a diagram showing numerical values ​​of analysis data obtained by electromagnetic field analysis software. DETAILED DESCRIPTION OF THE INVENTION

[0014] 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.

[0015] 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 with its own component.

[0016] 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.

[0017] 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.

[0018] 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, for example, copper wire or CNT (carbon nanotube). A rotating shaft 32 is assembled in the center hole of the rotor core 61. The rotating shaft 32 is rotatably supported in the housing 41 by bearings 42 and 43.

[0019] 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.

[0020] 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.

[0021] Next, the stator 50 and the rotor 60 will be described with reference to FIG.

[0022] 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.

[0023] 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.

[0024] 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 extending 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.

[0025] 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 conductor wire in 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 each winding portion 71, 72 wound around one is opposite to the winding direction of each winding portion 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, each main pole portion 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 in the circumferential direction.

[0026] 4 is a diagram showing 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. The capacitors 92 and 94 are, for example, ceramic capacitors or film capacitors.

[0027] The cathode of the diode 91 is connected to the first end 72a of the second winding portion 72, and the anode is 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 diode 91, current flows in one direction, from the anode side to the cathode side of the diode 91. Furthermore, the cathode of the diode 93 is connected to the first end 71a of the first winding portion 71, and the anode is connected to the second end 72b of the second winding portion 72. As a result, the field current flowing through each of the winding portions 71, 72 is rectified. In this embodiment, the number of windings of the second winding portion 72 is greater than the number of windings of the first winding portion 71.

[0028] 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 hardware electronic circuits, the functions can be provided by digital circuits including multiple logic circuits or analog circuits. For example, the microcomputer 31 executes programs stored in a non-transitory tangible storage medium (NSS) that serves as its own storage unit. The programs include programs for controlling the rotating electric machine 40. A method corresponding to the programs is performed by executing a set of instructions that constitute the programs. The storage unit is, for example, a non-volatile memory. The programs stored in the storage unit can be updated via a communication network such as the Internet, for example, via OTA (Over The Air) or other means.

[0029] Control device 30 generates drive signals that turn on and off each of switches SUp to SWn that constitute inverter 20. Specifically, control device 30 generates drive signals that turn on and off each of switches SUp to SWn and outputs the generated drive signals to the gates of each of switches SUp to SWn in order to convert DC power output from DC power supply 10 into AC power and supply it to U-, V-, and W-phase windings 52U, 52V, and 52W. As a result, in each phase, the upper arm switches and the lower arm switches are alternately turned on with dead times therebetween.

[0030] Control device 30 turns on and off each of switches SUp to SWn so as to pass 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 through each of phase windings 52U, 52V, 52W. The fundamental current is a current that mainly serves to generate torque in rotating electric machine 40. The high-frequency current is a current that mainly serves to excite first and second winding portions 71 and 72 that constitute field winding 70, thereby inducing a field current in field winding 70. The phase currents flowing through phase windings 52U, 52V, 52W are shifted by 120 electrical degrees.

[0031] 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 greater than or equal to 2) 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.

[0032] 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.

[0033] 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 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 diode 91. The flow of current through the closed circuit including the second winding portion 72 and the 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.

[0034] 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 ring member 102 covering the rotor main section 101 and the coil end covers 103 and 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.

[0035] The rotor 60 is broadly divided into a rotor main section 101, a cylindrical ring member 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 of both axial ends 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 center hole of the rotor core 61. The field winding 70 is made up of a plurality of winding units 110 arranged in a circumferential direction. The coil end covers 103 and 104 are provided to cover the coil ends of the field winding 70 on both axial sides.

[0036] 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.

[0037] The circuit module 106 has 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.

[0038] Heat sink 108 is fixed to one of the axial ends of component holder 107, on the side opposite rotor core 61 (the right side in the figure). Heat sink 108 is made of, for example, aluminum. By fixing heat sink 108 to the axial end face of component holder 107, heat generated in diodes 91 and 93 and capacitors 92 and 94 when current is applied to component holder 107 is released via heat sink 108.

[0039] The circular member 102 is formed by using metal wire 131 and winding the wire 131 in multiple layers around the outer periphery of the plurality of winding units 110 assembled to the rotor core 61. The circular member 102 surrounds each main pole 62 of the rotor core 61 and the field winding 70 from the radially outer side. The circular member 102 corresponds to an outer periphery covering part that covers the main pole 62 and the field winding 70 from the outer periphery side.

[0040] Fig. 9 is an exploded perspective view of the winding unit 110 in the rotor main section 101, and Fig. 10 is a cross-sectional view showing the cross-sectional structure of a portion of the rotor main section 101. Note that Fig. 10 depicts the annular member 102 shown in Fig. 5 and other figures as a structure for holding the field winding 70 wound around the main pole section 62 of the rotor core 61.

[0041] 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 the axial direction as the longitudinal direction, and is assembled to the rotor core 61 with the main pole section 62 of the rotor core 61 inserted into its hollow section. In this embodiment, the winding units 110 form a "pole coil."

[0042] The winding unit 110 has a first coil module 111 that is on the radially outer side when attached to the main pole section 62, and a second coil module 112 that is on the radially inner side. 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.

[0043] The first coil module 111 has an annular coil body 121 formed by winding a conductor material made of a rectangular wire multiple times in the circumferential and radial directions, and a thin plate-like insulator 122 provided integrally with the coil body 121. The insulator 122 has a portion that extends circumferentially and covers the outer peripheral portions on the radially outer and inner sides of the coil body 121, and a portion that extends radially and covers the hollow portion of the coil body 121. In other words, the outer peripheral portion on the radially outer side, the inner peripheral portion on the radially inner side, and the hollow portion of the coil body 121 are insulated and coated with the insulator 122.

[0044] The second coil module 112 has an annular coil body 123 formed by winding a conductor material made of a rectangular wire multiple times in the circumferential and radial directions, and a thin plate-like insulator 124 provided integrally with the coil body 123. The insulator 124 has a portion that extends circumferentially and covers the outer peripheral portions on the radially outer and inner sides of the coil body 123, and a portion that extends radially and covers the hollow portion of the coil body 123. In other words, the outer peripheral portion on the radially outer side and the inner peripheral portion and hollow portion of the coil body 123 are insulated and coated with the insulator 124.

[0045] The coil body 121 of the first coil module 111 is, for example, an α-winding coil in which a conductive wire is wound in an α-winding manner. The coil body 123 of the second coil module 112 is a continuously wound coil in which a conductive wire is continuously wound in a predetermined circumferential direction. In the first coil module 111, two conductive wire ends 125 are drawn out in the axial direction, and in the second coil module 112, two conductive wire ends 126 are drawn out in the axial direction. In each of the winding units 110 arranged in the circumferential direction, the conductive wire ends 125, 126 are connected to each other, so that the multiple first coil modules 111 provided on each main pole part 62 are connected in series, and the multiple second coil modules 112 provided on each main pole part 62 are connected in series.

[0046] The conductor wire used for the coil bodies 121, 123 is, for example, a flat wire having a substantially rectangular cross section (specifically, a substantially rectangular shape). The flat wire is composed of a conductor portion made of aluminum or the like and an insulating layer covering the conductor portion. However, a round wire having a circular cross section can also be used as the conductor wire. Note that the coil structure of each coil module 111, 112 is optional; for example, the coil bodies 121, 123 can both be continuous wound coils.

[0047] As shown in Fig. 10, the first coil module 111 has two radially wound layers of conductive wire, while the second coil module 112 has twelve radially wound layers of conductive wire. The number of layers in each of the coil modules 111, 112 is arbitrary, 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 windings (in other words, the number of rows of conductive wire in the circumferential direction), with the number of windings being greater on the radially outer side than on the radially inner side. This improves the space factor of the field winding 70.

[0048] Next, a description will be given of the configuration of the circular ring member 102. Fig. 11 is a vertical cross-sectional view showing the winding structure of the wire 131 around the circular ring member 102. In Fig. 11, the left-right direction is the axial direction, and the up-down direction is the radial direction.

[0049] As shown in FIG. 11 , the wire rods 131 are wound in multiple layers (four layers in the figure) in the radial direction while contacting each other in the axial direction. The wire rods 131 are preferably rectangular metal wires having a rectangular cross section. The wire rods 131 are preferably magnetic materials, specifically SUS430, SUS631, piano wire, or the like. By using rectangular wires as the wire rods 131, gaps are less likely to form between the wire rods 131 in the ring member 102. This prevents the wire rods 131 from collapsing or deforming in the ring member 102. Furthermore, the space factor in the ring member 102 is increased, thereby increasing the strength of the ring member 102.

[0050] Moreover, the wire rods 131 are wound around the circular member 102 while being linearly aligned in both the axial and radial directions. In this case, because the wire rods 131 are wound around the circular member 102 while being aligned in the axial direction, the outer circumferential surface (the radially outer circumferential surface) of the circular member 102 becomes flat. Therefore, the mechanical space between the rotor 60 and the stator 50 (the gap between the outer circumferential surface of the circular member 102 and the stator 50) can be kept constant in the axial direction. Furthermore, because the wire rods 131 are wound around the circular member 102 while being aligned in the radial direction, the circular member 102 is divided at predetermined intervals in the axial direction. Therefore, eddy currents are reduced in the circular member 102.

[0051] The annular member 102 and the coil end covers 103, 104 are provided radially outside the main pole portion 62 and the field winding 70, and are continuous in the axial direction with their axial end faces facing each other.

[0052] 10, the annular member 102 is provided in a ring shape in the circumferential direction, and its radial thickness is uniform in the circumferential direction. In the rotor core 61, each main pole portion 62 is a ring-shaped member that extends radially from the rotor axis and does not have a protruding portion that protrudes in the circumferential direction at its radially outer end. The annular member 102 is a separate member from the main pole portion 62, and is provided in contact with the outer peripheral surface of the main pole portion 62 on the radially outer side.

[0053] By making the annular member 102 a ring-shaped member, the centrifugal force generated in the field winding 70 can be received by the entire ring, and the resistance of the annular member 102 to tensile stress generated in the circumferential direction is increased. For example, in a configuration in which the rotor core 61 has a protruding portion that protrudes in the circumferential direction at the radially outer end of each main pole portion 62, that is, a configuration in which the protruding portion on the outer periphery is integrally formed as a main pole portion, local stress concentration occurs at the inside corner portion where the protruding portion joins. In contrast, by making the annular member 102 a ring-shaped member separate from the main pole portion, local stress concentration is suppressed.

[0054] The circular member 102 is designed to meet the strength requirements for properly holding the field winding 70 and the performance requirements for improving the performance of the rotating electric machine 40. Specifically, the material of the circular member 102 is selected based on the relationship shown in FIG. 12.

[0055] FIG. 12 shows the relationship between the magnetic flux density B50 [T] of the annular member 102 when the magnetizing force is 5000 A / m and the tensile strength Ts [MPa] of the metal material constituting the annular member 102. The relationship in FIG. 12 was created based on the analysis results using the electromagnetic field analysis software JMAG (JMAG-Designer Ver. 22.0). This relationship was created based on the analysis results under the following conditions: the load on the rotating electric machine 40 is assumed to be half of the full load; the coil magnetomotive force of the stator 50 is 1500 AT; the coil magnetomotive force of the field winding 70 is 1200 to 1400 AT; the outer diameter φ of the stator core is 230 mm; and the rotor coil space factor is constant. FIG. 13 shows the numerical values ​​of the analysis data obtained using the electromagnetic field analysis software.

[0056] The relationship in Figure 12 defines the material of the annular member 102 that satisfies both the strength requirements of the field winding 70 and the performance requirements of the rotating electric machine 40. Specifically, the annular member 102 is If B50<0.9, Ts≧920*B50^2-2520*B50+2000 ···(1) Satisfy the relationship between When B50≧0.9, Ts≧230*B50^2-680*B50+900 ···(2) It is desirable that the relationship between the above is satisfied.

[0057] The above relational expressions (1) and (2) are approximate expressions obtained from the analysis data shown in Fig. 13. In this embodiment, different relational expressions are defined for the case where the magnetic flux density B50 is relatively low and the case where the magnetic flux density B50 is relatively high.

[0058] The tensile strength Ts and magnetic flux density B50 differ depending on the material used for the circular ring member 102. Fig. 14 is a diagram showing the relationship between the radial thickness (ring thickness) of the circular ring member 102 and the torque of the rotating electric machine 40 for a plurality of metal materials with different magnetic flux densities B50.

[0059] 14 shows that for all metal materials, the torque of the rotating electrical machine 40 decreases as the ring thickness increases. Furthermore, comparing the metal materials, the more ferromagnetic the material, the more easily the desired torque can be achieved even with a larger ring thickness. This means that the more ferromagnetic the material, the greater the tolerance for ring thickness.

[0060] Fig. 15 is a diagram showing the relationship between magnetic flux density B50 and ring thickness when the same predetermined torque is realized in rotating electric machine 40. Fig. 15 shows that the larger the magnetic flux density B50, the larger the ring thickness, i.e., the larger the allowable value for ring thickness.

[0061] Here, when CFRP (Carbon Fiber Reinforced Plastics), a common high-strength material, is used as the material for the ring member 102, its tensile strength Ts is greater than that of a magnetic material, for example, 2000 MPa. In this case, if a magnetic material is used instead of the non-magnetic CFRP, the tensile strength Ts will be lower than that of CFRP, but the ring member 102 can be made thicker to compensate for the reduced strength, making it possible to realize a high-torque motor.

[0062] Next, FIG. 16 shows the relationship between the magnetic flux density B50 and the tensile strength Ts [MPa] of the annular member 102 when a full load is assumed as the load on the rotating electric machine 40. This relationship, like the above, was created based on the analysis results using the electromagnetic field analysis software JMAG (JMAG-Designer Ver. 22.0). The relationship in FIG. 16 was created based on the analysis results under the following conditions: a full load is assumed as the load on the rotating electric machine 40; the coil magnetomotive force of the stator 50 is 3000 AT; the coil magnetomotive force of the field winding 70 is 2400 to 2800 AT; the stator core outer diameter φ is 230 mm; and the rotor coil space factor is constant. FIG. 17 shows the numerical values ​​of the analysis data obtained using the electromagnetic field analysis software.

[0063] The relationship in Figure 16 defines the material of the annular member 102 that satisfies both the strength requirements of the field winding 70 and the performance requirements of the rotating electric machine 40. Specifically, the annular member 102 is If B50<0.75, Ts≧-1540*B50+2000 (3) Satisfy the relationship between When B50≧0.75, Ts≧150*B50^2-500*B50+1140 ···(4) It is desirable that the relationship between the above is satisfied.

[0064] The above relational expressions (3) and (4) are approximate expressions obtained from the analysis data shown in Fig. 17. In this embodiment, different relational expressions are defined for the case where the magnetic flux density B50 is relatively low and the case where the magnetic flux density B50 is relatively high.

[0065] According to the present embodiment described above in detail, the following excellent effects can be obtained.

[0066] In the rotor 60, centrifugal force is applied to the field winding 70 during rotation, and therefore the circular member 102 surrounding the field winding 70 must have a strength sufficient to withstand the centrifugal force. On the other hand, from the viewpoint of the performance of the rotating electric machine 40, it is desirable to increase the magnetic flux density in the gap between the rotor 60 and the stator 50, and it is therefore desirable to make the circular member 102 from a magnetic material. In view of this, in order to satisfy the strength requirements of the field winding and the performance requirements of the rotating electric machine, the tensile strength Ts of the circular member 102 and the magnetic flux density B50 are set to satisfy a predetermined relationship (the relationship shown in (1) and (2) above and in FIG. 12, or the relationship shown in (3) and (4) above and in FIG. 16).

[0067] The above relationship specifically stipulates that when a material with a relatively low magnetic flux density B50 is used, a material with a high tensile strength Ts should be used so that sufficient strength can be achieved even if the thickness of the circular member 102 is small. On the other hand, when a material with a relatively high magnetic flux density B50 is used, the thickness of the circular member 102 is allowed to be increased, so this relationship specifically stipulates that a material with a low tensile strength Ts can be used. This makes it possible for the circular member 102 to satisfy both the strength requirements and the magnetic flux density requirements. As a result, the field winding 70 can be properly held by assembling the circular member 102, and the performance of the rotating electric machine 40 can be ensured.

[0068] Furthermore, in each of the above relationships between the tensile strength Ts and the magnetic flux density B50 of the ring member 102, taking into consideration that the relationship differs between a region where the magnetic flux density B50 is relatively small and a region where the magnetic flux density B50 is relatively large, the relationship between the tensile strength Ts and the magnetic flux density B50 is varied depending on the magnetic flux density B50. This allows the use of suitable metal materials for the ring member 102 over a wide range of magnetic flux densities B50.

[0069] In the rotor core 61, each main pole portion 62 extends radially from the rotor axis and does not have a protruding portion protruding in the circumferential direction at its radially outer end, while the annular member 102 is a separate member from the main pole portion 62 and is provided in contact with the outer peripheral surface of the main pole portion 62 on the radially outer side. In this case, unlike a configuration in which the rotor core has a circumferentially extending portion (protruding portion) at its outer periphery, the annular member 102 does not experience stress concentration at its internal corners and bears stress over its entire circumferential circumference. Therefore, a circular member 102 having the desired strength can be suitably realized using the relationships shown in Figures 12 and 16.

[0070] (Other embodiments) The above embodiment may be modified as follows, for example.

[0071] The annular member 102 may be configured such that, instead of winding the wire 131 multiple times around the main pole 62 and the field winding 70, a member that has been formed into an annular (ring-like) shape in advance is assembled to the radially outer side of the main pole 62 and the field winding 70.

[0072] The relationship shown in Figure 12, that is, the relationship of the approximate formula obtained from the analysis data in Figure 13, is It may be one that satisfies "Ts≧−2000*B50+2000 and Ts≧−150*B50+650." In other words, the relationship shown in FIG.

[0073] Furthermore, the relationship shown in Fig. 16, i.e., the relationship of the approximate expression found from the analysis data in Fig. 17, may satisfy "Ts≧-1450*B50+2000 and Ts≧-240*B50+1100." In other words, the relationship shown in Fig. 16 may be approximated by two linear expressions.

[0074] In the stator 50, the stator core may not be provided with teeth.

[0075] The rotating electric machine is not limited to a rotating electric machine used as an in-vehicle main engine, but may also be, for example, a rotating electric machine used as an ISG (Integrated Starter Generator) which is a motor and generator.

[0076] 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. [Explanation of symbols]

[0077] 60... rotor, 61... rotor core, 62... main pole portion, 70... field winding, 102... annular member.

Claims

1. a rotor core (61) having a plurality of main pole portions (62) provided for each of the magnetic poles arranged in the circumferential direction; a field winding (70) provided around each of the main pole portions; a metal annular member (102) provided so as to surround each of the main pole portions and the field winding from the radially outer side; A wound field rotor (60) comprising: When the tensile strength of the annular member is Ts [MPa] and the magnetic flux density when the magnetizing force is 5000 A / m is B50 [T], When B50<0.9, Ts≧920*B50^2-2520*B50+2000 Satisfying the relationship, When B50≧0.9, Ts≧230*B50^2-680*B50+900 A wound field rotor that satisfies the relationship:

2. a rotor core (61) having a plurality of main pole portions (62) provided for each of the magnetic poles arranged in the circumferential direction; a field winding (70) provided around each of the main pole portions; a metal annular member (102) provided so as to surround each of the main pole portions and the field winding from the radially outer side; A wound field rotor (60) comprising: When the tensile strength of the annular member is Ts [MPa] and the magnetic flux density when the magnetizing force is 5000 A / m is B50 [T], When B50<0.75, Ts≧−1540*B50+2000 Satisfying the relationship, When B50≧0.75, Ts≧150*B50^2-500*B50+1140 A wound field rotor that satisfies the relationship:

3. In the rotor core, each of the main pole portions extends radially from a rotor axis center, and does not include a protruding portion protruding in a circumferential direction at a radially outer end thereof, 3. The wound field rotor according to claim 1, wherein the annular member is a separate member from the main pole portion and is provided in contact with an outer peripheral surface of the main pole portion on the radially outer side.

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