WO2014024023A2

WO2014024023A2 - Rotor of rotary electric machine

Info

Publication number: WO2014024023A2
Application number: PCT/IB2013/001709
Authority: WO
Inventors: Eiji Yamada; Ryoji MIZITANI; Kaoru Kubo; Kiroki KATO; Shintaro Chinen; Hideo Nakai; Kenji Hiramoto
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2012-08-07
Filing date: 2013-08-02
Publication date: 2014-02-13
Also published as: WO2014024023A3; JP2014036448A; WO2014024023A8

Abstract

A rotor (14) includes: a rotor core (24) having rotor salient poles (32) disposed in circumferential directions of the rotor core (24); a rotor coil (28n, 28s, 30n, 30s) which is formed by windings wound around the rotor salient poles (32) and whose external shape is fixed; and a retainer member (36) that retains the rotor coil (28n, 28s, 30n, 30s) on the rotor core (24), and that has a T sectional shape and has a leg portion (50) that is latched to a radially inner-side portion of the rotor core (24), and a beam portion (52a, 52b) which is connected to a connecting portion that includes a radially outer end portion of the leg portion (50) and which extend from the connecting portion in two opposite directions orthogonal to the leg portion (50). The external surface of the rotor coil has a non-contact portion that does not contact the retainer member (36).

Description

ROTOR OF ROTARY ELECTRIC MACHINE

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] The invention relates to a rotor of a rotary electric machine and, more particularly, to a rotor of a rotary electric machine which is provided with rotor windings.

2. Description of Related Art

[0002] There exists a type of rotary electric machine that employs a rotor provided with rotor windings. For example, Japanese Patent Application Publication No. 2009-112091 (JP 2009-112091 A) describes a rotary electric machine that forms a rotating magnetic field by causing alternating current to flow through stator windings, and causes a spatial harmonic component of the rotating magnetic field to link with rotor windings so as to produce induced current in the rotor windings. In this construction, the rotor windings are individually wound around salient poles of the rotor, and the rotor windings are short-circuited via diodes so that the induced currents are rectified, whereby each salient pole of the rotor functions as a magnet that has a fixed magnetization direction. The foregoing patent application publication states that this construction is able to utilize torque caused by the spatial harmonic component in addition to the torque caused by the fundamental component of the rotating magnetic field.

[0003] Japanese Patent Application Publication No. 9-322457 (JP 9-322457 A) describes a rotor wedge that restrains field coils wound on an electricity generator rotor from flying out due to centrifugal force when the electricity generator rotor rotates at high speed. The rotor wedge is fitted to a widest portion of a slot of the rotor core after field coils are buried in the slot. In this publication, it is stated that when the electricity generator rotor rotates at high speed, very large stress occurs in a shoulder portion corner of the rotor wedge that contacts the rotor core, and therefore that the shoulder portion corner is provided with a cut that has a predetermined curvature radius. [0004] Japanese Patent Application Publication No. 2010-41754 (JP 2010-41754 A) states that due to centrifugal force during rotation of a rotary element provided with a commutator, a rotary element's winding wire protrudes from a slot of a laminated core around which the rotary element's winding wire is wound, and describes a wedge as a winding wire holder member that prevents the aforementioned protrusion of the rotary element's winding wire. The publication also states that if the thickness of the rotary element's winding wires used in an electric motor is changed, the size of the space in which the wedge can be inserted changes, and that even in such a case, a winding wire holder member that is elastically deformable is used instead of various wedges prepared beforehand.

[0005] In an apparatus that includes a related-art rotor wedge and a winding wire holder member, a retainer member for retaining the rotor coils is disposed so as to prevent a rotor coil from flying out due to centrifugal force when the rotor rotates.

[0006] In order to further firmly fix the retainer member to the rotor core, a construction is sometimes adopted in which a latch portion is provided on an inner peripheral side of the rotor core as well and the retainer member is provided in a T shape. In such a construction, if a rotor coil contacts the retainer member due to centrifugal force, greater stress sometimes occurs in a connecting portion of the T shape or the like than in other portions of the retainer portion.

SUMMARY OF THE INVENTION

[0007] The invention provides a rotor of a rotary electric machine which is capable of reducing the stress that occurs in a retainer member that retains a rotor coil.

[0008] An aspect of the invention relates to a rotor of a rotary electric machine, the rotor including: a rotor core having a plurality of salient pole portions that are disposed on an outer periphery of the rotor core in a circumferential direction; a rotor coil which is formed by a plurality of windings wound around the salient pole portions and whose external shape is fixed; and a retainer member that retains the rotor coil on the rotor core, the retainer member having a T sectional shape and having a leg portion that is latched to a radially inner-side portion of the rotor core, and a beam portion which is connected to a connecting portion that is an end portion of the leg portion at a radially outer side in a radial direction. The beam portion includes a first beam portion and a second beam portion that extend from the connecting portion in two opposite directions orthogonal to the leg portion. The external surface of the rotor coil has a non-contact portion that does not contact the retainer member.

[0009] A curvature radius of a corner portion of the rotor coil that faces the connecting portion of the retainer member may be smaller than a curvature radius of the connecting portion of the retainer member.

[0010] The retainer member may be made of a non-magnetic material, and the leg portion may contain a magnetic member that extends in the radial direction.

[0011] The rotor coil may include: an induction coil that produces induced current when linked by a spatial harmonic component of a rotating magnetic field produced by a stator portion of the rotary electric machine; and a rectification portion that is connected to the induction coil and that rectifies the induced current.

[0012] The rotor coil may include a common coil that is disposed more radially inward in the radial direction of the salient pole portions than the induction coil and that is connected in series to the induction coil.

[0013] According to the rotor of a rotary electric machine described above, the stress that occurs in the retainer member that retains the rotor coil can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

FIG. 1A is a diagram showing a construction of a rotary electric machine in accordance with an embodiment of the invention, FIG. IB is an enlarged view of a slot portion, and FIG. 1C is an enlarged partial view of a distal end portion of the rotor slot;

FIG. 2 is a diagram showing results of a simulation of the state of stress in a retainer member in an example for comparison in which a rotor coil is not provided with a non-contact portion for the retainer member;

FIG. 3 is a diagram showing results of a simulation of the state of stress in the retainer member in a rotor of an rotary electric machine in accordance with the embodiment of the invention;

FIG. 4 is a diagram showing a connection relationship among induction coils, common coils and a rectification portion in a rotary electric machine that employs the rotor of the embodiment of the invention; and

FIG. 5 is an equivalent equivalent circuit diagram.

DETAILED DESCRIPTION OF EMBODIMENTS

[0015] With reference to the drawings, embodiments of the rotor of a rotary electric machine of the invention will be described in detail below. Although a rotor in which four types of rotor coils are disposed on slot portions of a rotor core will be described below, this is a mere example. The number of types of rotor coils disposed on the slot portions may also be other than four. For example, it is permissible to adopt a construction in which rotor coils of only one type are disposed on the slot portion or a construction in which rotor coils of two types are disposed.

[0016] Furthermore, although the rotor coils disposed on the slot portions which are described below are induction coils and common coils that utilize a spatial harmonic component of a rotating magnetic field produced by a stator, this is merely to illustrate an example of a rotary electric machine that has rotor coils. It suffices that the coils disposed on the slot portions are rotor coils, and the coils may also be field coils or the like.

[0017] In the rotary electric machines described below, the number of salient poles of the rotor, the number of slots, the wire diameter of rotor coils, the number of phases of the stator, the number of poles, etc., are merely illustrative, and can be changed as appropriate according to specifications of the rotor of a rotary electric machine.

[0018] In the description below, the same or comparable elements are denoted by the same reference characters in all the drawings, and redundant descriptions are omitted. [0019] FIGS. 1A to 1C are diagrams illustrating the construction of a rotor 14 of a rotary electric machine. FIG. 1A is a partial cutaway plan view of a rotary electric machine 10 in which a rotor 14 is used. FIG. IB is an enlarged view of a slot 34 of the rotor 14, and FIG. 1C is an enlarged view of a distal end portion of the slot 34.

[0020] The rotary electric machine 10 includes a stator 12 and a rotor 14, and is a three-phase synchronous rotary electric machine.

[0021] The stator 12 includes a stator core 16, a plurality of teeth 18 disposed in circumferential directions of the stator core 16, and stator coils 20 formed by winding a wire several turns on the teeth 18.

[0022] The stator core 16 is a circular annular magnetic member whose inner peripheral side is provided with the teeth 18. This stator core 16 is formed by stacking a plurality of electromagnetic steel sheets of a predetermined shape.

[0023] The stator coils 20 include three-phase windings, that is, U-phase windings, V-phase windings and W-phase windings. According to a distributed winding arrangement method determined beforehand, the winding wire of each phase is sequentially passed through slots 22 that are spaces between adjacent teeth 18, and is sequentially wound around predetermined ones of the teeth 18. FIG. 1A shows, for reference, the phases of the winding wires of the stator coils 20 wound around the teeth 18. As shown in FIG. 1A, U-phase windings, V-phase windings and W-phase windings are sequentially disposed in circumferential directions of the stator core 16. Therefore, the number of the teeth 18 is a multiple of three.

[0024] The rotor 14 includes a rotor core 24, a plurality of rotor salient poles 32 disposed in circumferential directions of the rotor core 24, and rotor coils 28n, 28s, 30n and 30s wound around the rotor salient poles 32.

[0025] The rotor core 24 is a circular annular magnetic material member whose outer peripheral portion is provided with the rotor salient poles 32 and whose center portion has a shaft hole in which a rotating shaft is fixed. In FIGS. 1A to 1C, the number of the rotor salient poles 32 is twelve. This rotor core 24 is formed by stacking a plurality of electromagnetic steel sheets of a predetermined shape. [0026] The rotor coils 28n, 28s, 30n and 30s are formed by a plurality of winding wires wound around the rotor salient poles 32. The rotor coils 28n, 28s, 30n and 30s are formed by passing winding wires through slots 34 formed between adjacent rotor salient poles 32 and winding the wires around the rotor salient poles 32 a predetermined number of turns for each rotor salient pole 32.

[0027] Four types of rotor coils 28n, 28s, 30n and 30s are disposed in each slot 34. Among these rotor coils, at least the rotor coils 28n and 28s are molded. A molding method employed herein is a resin molding method in which, using a resin molding die, the external shape of the coil is defined and the resin is solidified to fix the external shape. In some cases, partial resin molding may be carried out so that there is no degradation of the shape of a corner portion of any one of the rotor coils 28n and 28s.

[0028] The rotor coils 28n and 28s are coil windings disposed at a radially outer side in each slot 34 in the radial direction of the rotor core 24. The rotor coils 28n and 28s are windings that produce induced current when linked by a spatial harmonic component of a rotating magnetic field produced by the stator 12, and therefore can be referred to as induction coils.

[0029] The rotor coils 30n and 30s are coil windings that are disposed at a radially inner side of the rotor coils 28n and 28s in each slot 34 in the radial direction, in other words, disposed more radially inward in each slot 34 than the rotor coils 28n and 28s are. The rotor coils 30n and 30s are windings that are connected in series to both the rotor coils 28n and 28s, and therefore can be referred to as common coils. As for the wire diameter of the rotor coils 30n and 30s, although in the drawings, the wire of the rotor coils 30n and 30s appears thicker than the wire of the rotor coils 28n and 28s, the rotor coils 28n, 28s, 30n and 30s may have equal wire diameters, or the rotor coils 28n and 28s may have a larger wire diameter than the rotor coils 30n and 30s.

[0030] It is to be noted herein that the radial direction refers to a direction along a radius which is from the shaft hole of the rotor core 24. Furthermore, a direction orthogonal to a radial direction is a direction along the circumference of the rotor core 24, and can be referred to as circumferential direction. FIG. IB shows radial directions and circumferential directions.

[0031] Among the rotor coils 28n, 28s, 30n and 30s of four types in each slot 34, the rotor coil 28n, which is an induction coil, and the rotor coil 30n, which is a common coil, make a pair, and the rotor coil 28s, which is an induction coil, and the rotor coil 30s, which is a common coil, make another pair. The pair of coils 28n and 30n and the pair of coils 28s and 30s are wound around the rotor salient poles 32 on two opposite sides of the slot 34, respectively. In FIG. IB, the rotor salient pole 32 on the left side of the slot 34 in the sheet of the drawing is provided with the rotor coil 28n, which is an induction coil, and the rotor coil 30n, which is a common coil, and the rotor salient pole 32 on the right side of the slot 34 is provided with the rotor coil 28s, which is an induction coil, and the rotor coil 30s, which is a common coil.

[0032] The meanings of the suffixes "n" and "s" of the rotor coils 28n, 28s, 30n and 30s of the four types, the interconnection relationship of the coils, the actions thereof, etc., will be explained later.

[0033] A retainer member 36 disposed in each slot 34 is a member having a T shape in section which retains the rotor coils 28n, 28s, 30n and 30s on the rotor core 24. The retainer member 36 includes a leg portion 50 that extends in a radial direction, and beam portions 52a and 52b which are connected to a connecting portion that includes a radially outer end portion of the leg portion 50 and which extend from the connecting portion in opposite directions orthogonal to the leg portion 50. This retainer member 36 is made of a resin that is a non-magnetic material and an electrically insulating material. It suffices that the retainer member 36 is made of a non-magnetic material, that is, the retainer member 36 may also be made of a material other than resin.

[0034] The leg portion 50 of the retainer member 36 is a column portion in the T shape of the retainer member 36, and a radially inner-side end portion 56 of the leg portion 50 is latched into a latch groove 54 that is formed in an inner periphery-side portion (radially inner portion) of the rotor core 24. As a result, the retainer member 36 is firmly fixed to the rotor core 24. Furthermore, the leg portion 50 performs the function of separating the rotor coils 28n and 30n and the rotor coils 28s and 30s from each other. [0035] The beam portions 52a and 52b of the retainer member 36 are a head (upper) portion in the T shape, and extend in the opposite circumferential directions orthogonal to the leg portion 50 from the connecting portion that includes the radially outer end portion of the leg portion 50. Each of the beam portions 52a and 52b is latched to a latch depression portion provided in a radially outer end portion of an adjacent one of the two rotor salient poles 32 flanking the slot 34. The beam portions 52a and 52b perform the function of restraining the rotor coils 28n, 28s, 30n and 30s from flying radially outward due to the centrifugal force during rotation of the rotor 14.

[0036] A magnetic member 44 is housed within the leg portion 50 made up a non-magnetic material, and extends in the radial direction. The dimension of the magnetic member 44 in the radial direction is set substantially equal to the radial length of a region in which the rotor coils 28n and 28s are disposed. The magnetic member 44 functions as a magnetic flux guide member that guides, into the radial direction, the spatial harmonic component of the rotating magnetic field produced by the stator 12 and then guides it to the rotor coils 28n and 28s, which are induction coils. Because the leg portion 50 of the retainer member 36 houses therein the magnetic member 44, and is thicker or wider in a portion in which the magnetic member 44 is disposed than in other portions of the leg portion 50.

[0037] An insulator 35 is a sheet that electrically insulates each of the rotor coils 28n, 28s, 30n and 30s from the rotor core 24, and each of the rotor coils 28n, 28s, 30n and 30s from the retainer member 36. This insulator 35 may be of a pater material, a plastic sheet, etc.

[0038] Near the connecting portion of the retainer member 36 where the leg portion 50 and the beam portions 52 interconnect or intersect, clearances 60 are formed between the retainer member 36 and the rotor coil 28n and between the retainer member 36 and the rotor coil 28s. The clearances 60 are spaces for reducing the stress caused in the retainer member 36 by the rotor coils 28n and 28s due to the centrifugal force. Since the two clearances 60 are symmetrical about the retainer member 36, the relationship between the retainer member 36 and the rotor coil 28s alone will be described below as a representative example, with reference to an enlarged view shown in FIG. 1C.

[0039] When the rotor coil 28s is disposed in a given slot 34, the clearance 60 is formed as an external surface of the rotor coil 28s has a non-contact portion that does not contact the retainer member 36. An outline 62 of the rotor coil 28s shown in FIG. 1C is more radially inward in the radial direction than an outline 64 of the retainer member 36. The difference between the two outlines 62 and 64 represents the clearance 60. In a region with the clearance 60, the rotor coil 28s does not contact the retainer member 36. Portions of the rotor coil 28s at two opposite sides of the non-contact portion contact the retainer member 36.

[0040] The clearance 60 is formed if the curvature radius Rl of a corner portion of the rotor coil 28s that faces the connecting portion of the retainer member 36 is smaller than the curvature radius R2 of the connecting portion of the retainer member 36.

[0041] FIG. 2 and FIG. 3 show results of calculation regarding the effect that the clearance 60, that is, the non-contact portion, has on reduction of the stress that occurs in the retainer member 36 through the use of simulations. FIG. 2 shows results of calculation in a simulation without provision of the clearance 60, that is, the non-contact portion, and FIG. 3 shows results of calculation in a simulation with the clearance 60 provided, that is, the non-contact portion.

[0042] FIG. 2 shows distribution of stress that occurs in the retainer member 36 and the rotor coil 28s when centrifugal force acts on the rotor coil 28s in the direction indicated by a blank arrow, on the assumption that the outline of the retainer member 36 and the outline of the rotor coil 28s coincide with each other. When the outline of the retainer member 36 and the outline of the rotor coil 28s coincide, the centrifugal force that the rotor coil 28s receives acts in a radial direction from the center of gravity of the rotor coil 28s toward the outer periphery side, and presses the beam portion 52b at a point of intersection with the beam portion 52b. As a result, the point of action of the pressing force F is in a substantially intermediate portion of the length of the beam portion 52b of the retainer member 36. Therefore, since the pressing force F acts so as to force the beam portion 52b radially outward relative to the connecting portion, the stress that occurs in the retainer member 36 concentrates in the connecting portion of the retainer member 36, resulting in a large tensile stress.

[0043] FIG. 3 shows distribution of stress that occurs in the retainer member 36 and the rotor coil 28s when centrifugal force acts on the rotor coil 28s in the direction indicated by a blank arrow, on the assumption that the clearance 60 is formed between the outline 64 of the retainer member 36 and the outline 62 of the rotor coil 28s. In this case, in the clearance 60, the external surface of the rotor coil 28s does not contact the retainer member 36. Portions of the external surface of the rotor coil 28s that are on two opposite sides of the non-contact portion contact the retainer member 36.

[0044] Therefore, the point of action of the force by which the rotor coil 28n presses the retainer member 36 due to centrifugal force is dispersed to the two opposite sides of the non-contact portion. As shown in FIG. 3, at the two opposite sides of the non-contact portion of the connecting portion, a pressing force Fi acts on or near the leg portion 50, and a pressing force F₂ acts on or near the beam portion 52b. Since the pressing force is dispersed or divided to the forces Fi and F₂, the stress that occurs in the retainer member 36 is dispersed or divided as well, so that the tensile stress that occurs in the connecting portion is restrained to a smaller value than in the case shown in FIG. 2.

[0045] In the retainer member 36, the connecting portion is relatively low in mechanical strength. However, according to the construction shown in FIGS. 1A to 1C, the stress that concentratedly occurs in the connecting portion of the retainer member 36 can be reduced, so that in each slot 34, a space for disposing the rotor coils 28n, 28s, 30n and 30s can be secured without a need to change the width dimension of the retainer member 36 or the like. This secures good performance of the rotor coils 28n, 28s, 30n and 30s.

[0046] Subsequently to the description of the rotor 14 given above, operation and effects of the rotary electric machine 10 that employs the rotor 14 and, more particularly, the meanings of the suffixes "n" and "s" of the rotor coils 28n, 28s, 30n and 30s of four types, the interconnection relationship of the coils, the actions thereof, etc., will be explained with reference to FIGS. 4 and 5. FIG. 4 is a diagram showing the interconnection relationship of the rotor coils 28n, 28s, 30n and 30s of four types. FIG. 5 is an equivalent circuit diagram showing the interconnection relationship of the coils.

[0047] As shown in FIG. 4, an end of the rotor coil 28s and an end of the rotor coil 28s are interconnected via a first diode 38 and a second diode 40 that are rectification portions. The first diode 38 and the second diode 40 are interconnected in series so that their forward directions are opposite to each other. Due to this arrangement, current from the rotor coil 28n toward the rotor coil 28s is blocked, and current from the rotor coil 28s toward the rotor coil 28n is blocked. That is, no current flows in either direction between the two rotor coils 28n and 28s, which are induction coils.

[0048] Furthermore, an end of the rotor coil 30n and an end of the rotor coil 30s are connected to each other. Another end of the rotor coil 30n is connected to another end of the rotor coil 28n at a connecting point G, and another end of the rotor coil 30s is connected to a connecting point R between the first diode 38 and the second diode 40. Furthermore, another end of the rotor coil 28s is connected to the connecting point G.

[0049] Due to this connection relationship, the current that can flow in the rotor coil 28n, which is an induction coil, is only the current that passes through the rotor coil 28n, the first diode 38, the connecting point R, the rotor coil 30s, the rotor coil 30n, the connecting point G, the rotor coil 28n in this order. Furthermore, the current that can flow in the rotor coil 28s is only the current that passes through the rotor coil 28s, the second diode 40, the connecting point R, the rotor coil 30s, the rotor coil 30n, the connecting point G, the rotor coil 28s in this order.

[0050] Due to the foregoing arrangement, the induced current produced in the rotor coils 28n and 28s, which are induction coils, due to linkage by the spatial harmonic component of the rotating magnetic field produced by the stator 12 is rectified by the first diode 38 for the rotor coil 28n, and only the current in the rectification direction flows through the rotor coil 30n and the rotor coil 30s, which are common coils. Likewise, the induced current is rectified by the second diode 40 for the rotor coil 28s, and only the current in the rectification direction flows through the rotor coil 30n and the rotor coil 30s, which are common coils. [0051] Incidentally, since the leg portion 50 of the retainer member 36 is provided with the magnetic member 44 extending in the radial direction, the magnetic flux by the spatial harmonic component from the stator 12 is efficiently guided to the rotor coils 28n and 28s by the magnetic member 44. Incidentally, the magnetic member 44 may be omitted.

[0052] It is to be noted herein that by appropriately setting the winding directions of the rotor coils 28n, 28s, 30n and 30s, the magnetization direction of the rotor salient pole 32 around which the rotor coils 28n and 30n are wound and the magnetization direction of the rotor salient pole 32 around which the rotor coils 28s and 30s are wound can be made opposite to each other in terms of polarization. For example, if the setting of the winding directions shown in FIG. 5 is used, the magnetization direction of the rotor salient pole 32 around which the rotor coils 28n and 30n are wound can be made the same as the magnetization direction of an N-pole magnet, and the magnetization direction of the rotor salient pole 32 around which the rotor coils 28s and 30s are wound can be made the same as the magnetization direction of an S-pole magnet. In order to show this in FIG. 4, the rotor salient pole around which the rotor coils 28n and 30n are wound is specified as the rotor salient pole 32n, and the rotor salient pole 32 around which the rotor coils 28s and 30s are wound is specified as the rotor salient pole 32s. This is the meaning of the suffixes "n" and "s" of the rotor coils 28n, 28s, 30n and 30s of four types.

[0053] Using the connection relationship illustrated in FIG. 4 and FIG. 5, one of the two rotor salient poles 32 flanking the two opposite sides of each slot 34 of the rotor 14 can be used an N-pole magnet, and the other can be used as an S-pole magnet. In the construction shown in FIGS. 1A to 1C which includes twelve slots 34 and twelve rotor salient poles 32, the connection relationship among the rotor coils 28n, 28s, 30n and 30s disposed at each one of the slots 34 can be made the same as that illustrated in FIGS. 4 and 5. Due to this design, the twelve rotor salient poles 32 of the rotor 14 can be handled as an arrangement in which magnets utilized as N poles and the magnets utilized as S poles alternate with each other along the circumference of the rotor 14.

[0054] Incidentally, in the arrangement illustrated in FIGS. 4 and 5, the first diode 38 and the second diode 40 are used for two adjacent rotor salient poles 32, so that if twelve rotor salient poles 32 are provided, six pairs of the first diode 38 and the second diode 40 are used. However, it is possible to make an arrangement in which only one pair of the first diode 38 and the second diode 40 is used for the entire rotor 14. That is, the six rotor coils 28n are connected in series and are handled as one series-connected rotor coil 28n, and the six rotor coils 28s are connected in series and are handled as one series-connected rotor coils 28s, and the six rotor coils 30n are connected in series and are handled as one series-connected rotor coils 30n, and the six rotor coils 30s are connected in series and are handled as one series-connected rotor coils 30s. In this arrangement, the connection relationship illustrated in FIGS. 4 and 5 is used. Due to this, the number of pairs of the first diode 38 and the second diode 40 used in the entire rotor 14 can be made one.

[0055] Overall operation and effects of the rotary electric machine 10 will be described below. In the rotary electric machine 10, as alternating electric current is caused to flow through the three-phase winding wires, that is, the U-phase winding wire, the V-phase winding wire and the W-phase winding wire, of the stator coils 20 of the stator 12 in a predetermined sequence, a rotating magnetic field is produced on the teeth 18 of the stator core 16. The rotating magnetic field includes the fundamental component and the spatial harmonic component. The rotating magnetic field of the fundamental component acts on the rotor 14 so as to reduce the magnetic resistance between the teeth 18 and the rotor salient poles 32. Therefore, the rotor 14 rotates so that the rotor salient poles 32 are attracted or drawn to the rotating magnetic field, whereby torque occurs on the rotating shaft of the rotor 14. This torque is reluctance torque.

[0056] The spatial harmonic component of the rotating magnetic field links with the rotor coils 28n and 28s of the rotor 14, which are induction coils, and acts so that the twelve rotor salient poles 32 of the rotor 14 become magnets that serve as N poles or magnets that serve as S poles. Due to the interaction between the fixed magnetic field produced in the foregoing manner and the fundamental component of the rotating magnetic field produced by the stator 12, the rotor 14 rotates and torque occurs on the rotating shaft of the rotor 14. This torque is not reluctance torque, but a torque that corresponds to a kind of magnet torque caused by induced current. In this manner, the spatial harmonic component of the rotating magnetic field can be effectively utilized to increase the torque of the rotary electric machine 10.

[0057] According to the foregoing construction, the rotor includes rotor coils whose external shape has been fixed, and a retainer member that has a T sectional shape and that retains the rotor coils on the rotor core. With regard to some rotor coils, the external surface has a non-contact portion that does not contact the retainer member, and portions of the external surface at two opposite sides of the non-contact portion contact the retainer member. Due to this, the sites at which rotor coils are pressed against the retainer member due to centrifugal force during rotation of the rotor are dispersed, so that the stress that occurs in the retainer member 36 that retains the rotor coils can be reduced.

[0058] Furthermore, since the curvature radius of the corner portion of a rotor coil in the rotor is set smaller than the curvature radius of the connecting portion of the retainer member, the portion of the smaller curvature radius serves as the non-contact portion. Therefore, the rotor coils concerned contact the retainer member, with the contact sites dispersed to the two opposite sides of the non-contact portion, that is, the connecting portion side of the leg portion of the retainer member and the beam side of the retainer member.

[0059] In the rotor, the retainer member having a T sectional shape is made of a non-magnetic material. Therefore, when a plurality of rotor coils are disposed in a slot formed between adjacent rotor salient poles of the rotor core, these rotor coils can be electrically and spatially separated. Furthermore, since the leg portion of the retainer member is provided with the magnetic member that radially extends, the magnetic flux from the stator that faces the rotor can be efficiently guided by the magnetic member to the rotor and can be utilized at the rotor.

[0060] Furthermore, in the rotor, the rotor coils include induction coils that produce induced current due to magnetic flux from the stator, and a rectification portion that rectifies the induced current. Due to this, each rotor salient pole can be made a magnet that has a predetermined magnetization direction, and therefore the torque of the rotary electric machine can be increased.

[0061] Furthermore, in the rotor, the rotor coils include common coils that are disposed at a radially inner side of the induction coils in the radial direction regarding the rotor salient poles, and that are connected in series to the induction coils. Due to the common coils, the rotor salient poles can be efficiently made magnets each of which has a predetermined magnetization direction.

Claims

1. A rotor of a rotary electric machine, comprising:

a rotor core having a plurality of salient pole portions that are disposed on an outer periphery of the rotor core in a circumferential direction of the rotor core;

a rotor coil which is formed by a plurality of windings wound around the salient pole portions and whose external shape is fixed; and

a retainer member that retains the rotor coil on the rotor core, the retainer member having a T sectional shape and having a leg portion that is latched to a radially inner-side portion of the rotor core, and a beam portion which is connected to a connecting portion that is an end portion of the leg portion at a radially outer side in a radial direction,

wherein the beam portion includes a first beam portion and a second beam portion that extend from the connecting portion in two opposite directions orthogonal to the leg portion, and

the external surface of the rotor coils has a non-contact portion that does not contact the retainer member.

2. The rotor according to claim 1, wherein

a curvature radius of a corner portion of the rotor coil that faces the connecting portion of the retainer member is smaller than a curvature radius of the connecting portion of the retainer member.

3. The rotor according to claim 1 or 2, wherein

the retainer member is made of a non-magnetic material, and the leg portion contains a magnetic member that extends in the radial direction.

4. The rotor according to claim 1 or 2, wherein

the rotor coil includes:

an induction coil that produces induced current when linked by a spatial harmonic component of a rotating magnetic field produced by a stator portion of the rotary electric machine; and

a rectification portion that is connected to the induction coil and that rectifies the induced current.

5. The rotor according to claim 4, wherein

the rotor coil includes a common coil that is disposed more radially inward in the radial direction of the salient pole portions than the induction coil and that is connected in series to the induction coil.