Stator arrangement of vehicle AC generator

[0002] The present application is based on and claims priority from the following Japanese Patent Applications: Hei 10-334386, filed Nov. 25, 1998; Hei 11-214031, filed Jul. 28, 1999; and Hei 11-292607, filed Oct. 14, 1999; the contents of which are incorporated herein by reference.

[0003] 1. Field of the Invention

[0004] The present invention relates to a rotary electric machine, and particularly to a stator lead-wire arrangement of an AC generator for a vehicle.

[0005] 2. Description of the Related Art

[0006] Both star-connected phase-windings and delta-connected phase-windings are known as typical phase-windings of an AC generator. One lead-end of each of star-connected phase-windings is gathered at a suitable position, and the other lead-end thereof is connected to an outside electric load. On the other hand, both lead-ends of each delta-connected phase-windings are connected to form a triangle having three joints, which are connected to an outside electric load.

[0007] The above-described connection between different phase-windings is located at coil-end groups formed at opposite ends of a stator core. The lead-end of each phase-winding extends along the ridge of the coil-end groups to the lead-ends of other phase-windings. These lead-ends are bound by threads to the coil-end groups to prevent the lead-ends from contacting with a rotor or a housing, as disclosed in JP-A-2-214445. It is also known that a portion of the lead-ends is inserted into stator's slots having additional conductor members to shorten the threads or reduce the number of threads to zero.

[0008] In the stator disclosed in JP-A-2-214445, the thread binding takes considerable work. Such thread binding work may hurt insulation coatings of the windings, resulting in an insulation problem.

[0009] It is also difficult to insert such lead-ends in some of the slots because of recent high power structure of the stator that has a high space factor of the winding.

[0010] Therefore, it is an object of the invention to provide an improved stator of a vehicle AC generator that has lead-ends easily and surely fixed to a coil-end group.

[0011] It is another object of the invention to provide a stator of a vehicle AC generator that has lead-ends well insulated from the coil-end group.

[0012] According to an aspect of the invention, a stator of a vehicle AC generator includes a stator core having a plurality of slots, a plurality of phase-windings formed of a plurality of conductor members. The stator winding has first and second coil-end groups formed of portions of the conductor members extending from the slots to opposite ends of the stator core. Each of the phase-windings has a lead-end which partially covered with an insulation member and extends along the first coil-end group to be connected to one another. The insulation member is bonded to the first coil-end group.

[0013] The insulation member has a thickness that provides distance to insulate the first coil-end group from the lead-ends.

[0014] In the stator, the insulation member can be an insulation tube through which the lead-end extends. The insulation tube can be formed of a textile that provides the insulation member with vibration resistance. The insulation member can be an insulation sheet disposed between the lead-end and the first coil-end group. The insulation member can be formed of an insulation adhesive resin.

[0015] Other objects, features and characteristics of the present invention as well as the functions of related parts of the present invention will become clear from a study of the following detailed description, the appended claims and the drawings. In the drawings:

[0016] FIG. 1 is a partially cross-sectional side view of an AC generator for a vehicle according to a first embodiment of the invention;

[0017] FIG. 2 is a fragmentary cross-sectional view of a stator according to the first embodiment;

[0018] FIG. 3 is a schematic perspective view of a base segment unit according to the first embodiment;

[0019] FIG. 4 is a portion of a winding diagram of a stator winding according to the first embodiment;

[0020] FIG. 5 is a portion of a winding diagram of a stator winding according to the first embodiment;

[0021] FIG. 6 is a portion of a winding diagram of a stator winding according to the first embodiment;

[0022] FIG. 7 is a main portion of a winding diagram of a stator winding according to the first embodiment;

[0023] FIG. 8 is a circuit diagram of the AC generator according to the first embodiment;

[0024] FIG. 9 is a fragmentary side view of a coil-end group of the stator according to the first embodiment;

[0025] FIG. 10 is a cross-sectional schematic view of a coil-end group according to the first embodiment cut along line X—X in FIG. 9;

[0026] FIG. 11 is a schematic perspective view of a base segment unit according to a second embodiment of the invention;

[0027] FIG. 12 is a cross-sectional schematic view of a coilend group according to a third embodiment;

[0028] FIG. 13 is a fragmentary side view of a coil-end group of the stator according to a fourth embodiment of the invention;

[0029] FIG. 14 is a cross-sectional schematic view of a coil-end group according to the first embodiment cut along line XIV—XIV;

[0030] FIG. 15 is a fragmentary side view of a coil-end group of the stator according to a fifth embodiment of the invention; and

[0031] FIG. 16 is a cross-sectional schematic view of a coil-end group according to the fifth embodiment cut along line XVI—XVI in FIG. 15.

[0032] A stator of a vehicle AC generator according to a first embodiment of the invention is described with reference to FIGS. 1-10.

[0033] Vehicle AC generator 1 includes stator 2 as an armature, rotor 3 as a magnetic field, a pair of front housing 4aand rear housing 4b, fastening bolts 4c, and rectifier 5. Front housing 4aand rear housing 4bsupport stator 2 therebetween and rotatably support rotor 3.

[0034] Rotor 3 rotates with shaft 6 and has Lundell type pole core 7, field coil 8, slip rings 9 and 10, mixed-flow-type cooling fan 11, and centrifugal cooling fan 12. Shaft 6 is linked with pulley 20 to be driven by an engine mounted in a vehicle (not shown).

[0035] Lundell type pole core 7 is formed of boss portion 71 fixed to shaft 6, disk portion 72 extending from opposite ends of boss portion 71 and twelve claw poles 73.

[0036] Mixed-flow-type cooling fan 11 is disposed near pulley 20 and rotates together with rotor 3. Mixed-flow-type cooling fan 11 has base plate 111 welded to the front surface of pole core 7, a plurality of inclined blades projecting from base plate 111 at an acute angle, and a plurality of right-angled blades. Centrifugal cooling fan 12 is disposed remote from pulley 20. Centrifugal cooling fan 12 has base plate 121 which is welded to the rear surface of pole core 7 and a plurality of right-angled blades.

[0037] The pair of housings 4aand 4bhas a plurality of air intake windows 41 at the opposite axial ends thereof and a plurality of air discharge windows 42 at opposite shoulder portions thereof around first coil-end group 31aof stator 2 and second coil-end group 31bthereof.

[0038] Rectifier 5 is disposed at a rear portion of AC generator 1 remote from pulley 20, so that first coil-end group 31ais disposed to correspond to rectifier 5.

[0039] Stator 2 includes stator core 32 having a plurality of slots 35, a plurality of conductor members forming a stator winding and insulators 34 insulating the conductor members from stator core 32, which is disposed between front housing 4aand rear housing 4b.

[0040] As shown in FIG. 2, stator core 32 has a plurality of (e.g. thirty six) slots 35 circumferentially formed at equal intervals to accommodate a plurality of (e.g. three) phase-windings.

[0041] The stator winding accommodated in the slots 35 is composed of a plurality of conductor members, and a set of an even number (e.g. four) conductor members are disposed in each slot 35. The four conductor members of each set are respectively disposed in the following radially aligned layers: innermost layer, inner middle layer, outer middle layer, and outermost layer. Each set of four conductor members in the same slot is included in one of the phase-windings.

[0042] These conductor members are connected in a prescribed pattern to form the stator winding. The conductor members has continuous portions in first coil-end group 31aand connection portions in second coil-end group 31b. One of the conductor members extending from each slot 35 is paired with another conductor member extending from another slot that is spaced apart at a prescribed pole-pitch.

[0043] One conductor member extending from one layer of one of slots 35 is paired with another conductor member extending from a different layer of another slot that is spaced apart at the prescribed pole-pitch, so that distances between the conductor members in the coil-end groups can be evenly provided.

[0044] For example, conductor member 331ain the innermost layer of one slot is paired with conductor member 331bin the outermost layer of the slot that is spaced apart therefrom at one pole-pitch in the clockwise direction. In the same manner, conductor member 332ain the inner middle layer is paired with conductor member 332bin the outer middle layer of the slot that is spaced apart therefrom at one pole-pitch in the clockwise direction.

[0045] The paired conductor members are respectively jointed by continuous portions including turn portions 331cand 332cat one end of stator core 32.

[0046] Therefore, at one end of stator core 32, the continuous portion that joints the conductor members in the outer middle layer and the inner middle layer is surrounded by the continuous portion that joints the conductor members in the outermost layer and the innermost layer. Thus, the continuous portion of one pair of conductor members is surrounded by the continuous portion of another pair of conductor members that are disposed in the same pair of slots. The continuous portion of the conductor members in the outer middle layer and inner middle layer form an internal coil-end, and the continuous portions of the conductor members in the outermost and innermost layers form an external coil-end.

[0047] On the other hand, conductor member 332ain the inner middle layer in one slot is also paired with conductor member 331a′ in the innermost layer in another slot that is one pole-pitch spaced apart therefrom in the clockwise direction. In the same manner, conductor member 33lb′ in the outermost layer in the same one slot is paired with conductor member 332bin the outer middle layer in the same another slot that is one pole-pitch spaced apart therefrom in the clockwise direction. These conductor members are welded together at the other end of stator core 32.

[0048] Therefore, connection portions of the conductor members in the outermost layer and in the outer middle layer and connection portions of the conductor members in the innermost layer and in the outer middle layer are aligned in the circumferential direction at the other end of stator core 32. The connection of conductor members in the outermost layer and the conductor members in the outer middle layer and the connection of the conductor members in the innermost layer and conductor members in the inner middle layer form adjoining layers of coil-ends.

[0049] Thus, the connection portions of the conductor members are regularly disposed at the other end of stator core 32 without overlapping.

[0050] The plurality of the conductor members are provided by specific shape conductor segments having a fixed rectangular cross section. As shown in FIG. 3, the conductor members in the innermost layer and the outermost layer are provided by generally U-shaped large segment 331, and the conductor members in the inner middle layer and in the outer middle layers are provided by generally U-shaped small segment 332.

[0051] Large segment 331 and small segment 332 form base segment unit 33. A plurality of base segment units 33 are regularly inserted into the plurality of slots 35 to form a two-turn coil turning around stator core 32 twice. The two-turn coil is formed of a first turn coil and a second turn coil connected in series by a specific segment different from any one of the segments forming base segment unit 33. Three different specific segments are used in the stator according to the first embodiment.

[0052] A winding diagram of X-phase-winding of the three phase windings is explained with reference to FIGS. 4-7, where the conductor member in the outermost layer of the slot is indicated by a one-dot chain line, the conductor member in the outer middle layer of the slot is indicated by a broken line, the conductor member in the inner middle layer is indicated by a solid line, and the conductor member in the innermost layer is indicated by a two-dot chain line. First coil-end group 31ahaving the turn portions is shown at the top, and second coilend group 31bhaving the connection portions is shown at the bottom. The numerals shown at the middle between the top and bottom indicate respective slot numbers. The above arrangement is the same in FIGS. 4-7.

[0053] As shown in FIG. 4, base segment unit 33 of X-phase-winding is disposed in slot No. 1 and other slots at intervals of three slots. In second coil-end group 31b, one end of the conductor member extending from the outer middle layer (hereinafter referred to as the outer middle conductor member) of one of slots 35 is welded to an end of the conductor member extending from the outermost layer (hereinafter referred to as the outermost conductor member) of another slot that is one pole-pitch spaced apart therefrom in the clockwise direction. One end of the conductor member extending from the innermost layer (hereinafter referred to as the innermost conductor member) of one of slots 35 is welded to an end of the conductor member extending from the inner middle layer (hereinafter referred to as the inner middle conductor member) of another slot that is one pole-pitch spaced apart therefrom in the clockwise direction. Thus, lap-wound first sub-phase-winding 311, which has two turns each slot, is formed.

[0054] Lap-wound second sub-phase-winding 312 shown in FIG. 5 is also formed in the same manner as above. As shown in FIG. 6, lead-end 33mof first sub-phase-winding 311 is connected to lead-end 33nof second sub-phase-winding is connected to form four-turn X-phase-winding 315. The specific segment having the turn portion connecting lead-end 33mand lead-end 33nis different from any of large segment 311 and small segment 312 of base segment unit 33.

[0055] Y-phase winding and Z-phase-winding, which are formed in the same manner as X-phase-winding, are respectively disposed in those of slots 35 which are 120° different in electric phase from other phase-windings, as shown in FIG. 7. First lead-ends X1, Y1 and Z1 of X-phase winding, y-phase winding, and Z-phase winding are connected to each other to form neutral point 33k. Second lead-ends X2, Y2 and Z2 of X-phase winding, y-phase winding, and Z-phase winding are respectively connected to input terminals of rectifier 5. Thus, a DC power circuit including a star-connected stator winding and three-phase full-wave rectifier 5 is formed as shown in FIG. 8. Lead-end X2 connected to one of the input terminals of rectifier 5 extends from first coil-end group 31a.

[0056] The stator winding is formed as follows. Base segment unit 33 is formed so that turn portion 332cof U-shaped small segment 332 is surrounded by turn portion 331cof U-shaped large segment 331. Base segment unit 33 is inserted to slots 35 from an axial end of stator core 32 in the following manner: conductor member 331aof large segment 331 is disposed in the innermost layer of one slot; conductor member 332aof small segment 332 is inserted into the inner middle layer of the above-said one slot; conductor member 331bof the same large segment 331 is inserted into the outermost layer of another slot that is spaced apart at one pole-pitch from the one slot in the clockwise direction; and the other conductor member of the same small segment 332 is inserted into the outer middle layer of the above-said another slot.

[0057] As a result, four conductor members, such as conductor members 331a, 332a, 332b′ and 331b′ shown in FIG. 2, are aligned radially in each of all slots 35.

[0058] Thereafter, in second coil-end group 31b, connection portions 331dand 331eof the conductor members disposed in the outermost and the innermost layers are respectively bent to open the mouth of large segment 331 by one and a half slot-pitch.

[0059] On the other hand, connection portions 332dand 332eof the conductor members disposed in the outer middle and the inner middle layers are respectively bent to close the mouth of small segment 332 by one and a half slot-pitch. The above step is repeated for all base segment units 33.

[0060] Sub-phase-windings of each phase-winding are connected by specific segments as described before.

[0061] In second coil-end group 31b, connection portion 331e′ of the outermost conductor member and connection portion 332eof the outer middle conductor member are welded or soldered together, and connection portion 332dof the inner middle conductor member and connection portion 331d′ of the innermost conductor member are welded or soldered together, by a welder such as a supersonic welder, an arc welder, or a soldering tool. Thus, stator 2 is formed.

[0062] In first coil-end group 31a, lead-ends X1, and Z1 are extended along the ridge line of first coil-end group 31ato be connected to lead-end Y1, which extends in the axial direction, to form neutral point 33k. This connection is to shorten the length of the lead-ends extending along first coil-end group 31a.

[0063] As shown in FIG. 9, lead-end X1 of X-phase-winding (and also lead-end Z1 of Z-phase-winding) is partly covered by flexible textile insulation tube 333. As shown in FIG. 10, lead-end, which has a rectangular cross-section, is disposed on the ridge with its longer side down, thereby restricting the axial length of stator 2.

[0064] Insulation tube 333 is bonded to first coil-end group 31aby an adhesive made of a epoxy resin. Because textile insulation tube 333 is impregnated with the adhesive, lead-ends X1 and Z1 are also bonded together. Thus, lead-ends X1 and Z1 can be fixed to first coil-end group 31avery easily to be resistant to vibration. Insulation tube 333 has a thickness to form gaps between lead-ends X1 or Z1 and first coil-end group 31a.

[0065] The other lead-ends X2, Y2 and Z2 extend from first coil-end group 31aand connected to the respective input terminals of rectifier 5. One of insulation tubes 333 of both lead-ends X1 and Z1 can be omitted if the length thereof can be reduced by arranging lead-ends X2, Y2 and Z2. For example, if lead-end Z1 is shorter than the others, insulation tube 333 is applied only to lead-end X1.

[0066] A second embodiment of the invention is shown in FIG. 11. The outermost and inner most conductor members can be bent to close the mouth of large segment 331 of base segment unit 33 if the outer middle and inner middle conductor members are bent to open the mouth of small segment 332.

[0067] A third embodiment of the invention is shown in FIG. 12. Textile insulation sheets 335 can be disposed between each of lead-ends X1 and Z1 and first coil-end group 31ainstead of insulation tubes 333. Adhesive 334, made of heat-resistant insulation resin such as epoxy resin, is applied to cover insulation sheets 335 and lead-ends X1 and Z1. Insulation sheets 335 are made of varnished glass fiber. Thus, insulation sheets 335 and adhesive 334 can be applied easily after all the connection works are finished.

[0068] A fourth embodiment of the invention is shown in FIGS. 13 and 14. Lead-ends X1 and Z1 are covered with an insulation adhesive 336 made of a heat-resistant material such as epoxy resin or silicone resin, however, without any insulation tube or sheet. After lead-ends X1 and Z1 are extended along the ridge of first coil-end group 31atoward lead-end Y1 and connected together to form neutral point 33k, lead-ends X1 and Z1 are pressed against first coil-end group to reduce distance between lead-ends X1, Z1 and first coil-end group 31ato form gaps suitable for capillary function.

[0069] Thereafter, adhesive 336 is applied to lead-ends X1 and Z1 and turn portions 331cof first coil-end group 31a. Adhesive 336 spreads into many gaps because of the capillary function and forms internal insulation layers 336abetween each of lead-ends X1, Z1 and turn portions 331c. External insulation layers 336bare formed to cover lead-ends X1 and Z1.

[0070] As shown in FIG. 13, lead-ends X1 and Z1 are bonded by insulation layers 336bat a plurality of portions. The viscosity of adhesive 336 should be controlled to mainly form internal insulation layers 336a.

[0071] A fifth embodiment of the invention is shown in FIGS. 15 and 16.

[0072] Lead-ends X1 and Z1 respectively have bent portions B1 as well as common neutral point 33k. Lead-ends X1 and Z1 respectively extend along the ridge of first coil-end group 31aand bonded to the ridge at a plurality of portions thereof at bonded portions 338, which are formed from liquid resin 337, a known impregnation material, gathering in gaps between leadends X1, Z1 and first coil-end group 31a. In other words, bonded portions 338 are formed in some gaps between lead-ends X1, Z1 and the edges of turn portions 331cof first coil-end group 31a. Bonded portions 338 are not formed in other gaps between lead-ends X1, Z1 and the edges of turn portions 331c, thereby, to provide effective cooling surfaces of first coil-end group 31a. Resin 337 covers the whole surface of neutral point 33kto protect the same. Resin 337 also covers almost the whole surface of first coil-end group 31ato protect the same. Thus, resin 337 not only protects the surface of coil-end groups but bonds the conductor members together. Liquid resin 337 spreads into the inside of stator core 32 to bond adjacent portions of the stator 2.

[0073] In this embodiment, two lead-ends X1 and Z1 are respectively bent at bent portion B1 toward lead-end Y1. Then, lead-ends X1, Y1 and Z1 are welded together to form neutral point 33k. Thereafter, lead-ends X1 and Z1 are pressed against first coil-end group 31a. Liquid resin 337 having a suitable viscosity is then dropped from above first coil-end group 31aon neutral point 33kand other surfaces of first coil-end group 31aincluding lead-ends X1 and Z1, so that the most liquid resin 337 can get into the inside of stator 2 and thin coatings can be formed on first coil-end group 31a. Portions of liquid resin 337 gathers at portions of first coil-end group 31aadjacent to lead-ends X1 and Z1 and become solid to form bonded portions 338.

[0074] Thus, not only neutral point 33kand lead-ends X1 and Z1 are protected and fixed but also sufficient cooling surfaces are provided. Textile insulation tube 333 is effective to increase bonded portions.

[0075] The present invention can be applied to a stator having a delta-connected stator winding in the same manner. The lead-ends can be extended from second coil-end group 31b. The base segment unit 33 can have I-shaped segments instead of U-shaped segments. The present invention can be also applied to a stator winding formed of a continuous magnetic wire.

[0076] In the foregoing description of the present invention, the invention has been disclosed with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made to the specific embodiments of the present invention without departing from the broader spirit and scope of the invention as set forth in the appended claims. Accordingly, the description of the present invention in this document is to be regarded in an illustrative, rather than a restrictive, sense.