DESCRIPTION ROTATING ELECTRIC MACHINE STATOR AND ROTATING ELECTRIC MACHINE STATOR MANUFACTURING METHOD
TECHNICAL FIELD
[0001] The present invention relates to a rotating electric machine stator and a rotating electric machine stator manufacturing method that enable size reduction of a rotating electric machine by reducing constraint on the shape of an insulator.
BACKGROUND ART
[0002] For achieving high efficiency and size reduction in a rotating electric machine, it is conceivable that a coil wound around a stator of a rotating electric machine is formed with high density. For winding the coil with high density, it is required to ensure a space for winding and perform winding there with high regularity. The stator of a rotating electric machine is provided with an insulator formed by a thin insulating layer, in order to ensure insulation between a stator core and a coil. Examples of methods for mounting the insulator include a method of mounting, to the stator core, an insulator formed through injection molding with an insulating resin material in advance, and a method of setting a stator core into a molding

mold and performing integral molding with an insulating resin material, thereby manufacturing an insulator-equipped stator core.
[0003] Regarding the latter method, in particular, in the case of a small-size rotating electric machine, it is difficult to perform work for mounting a small insulator, and therefore the latter method is effective for simplifying the insulator mounting work. For integral molding of the insulator, it is necessary to receive a part of the stator core in the mold so as to perform positioning. At this time, since the stator core is formed by stacking magnetic metal sheets having a thickness of about 0.5 mm, the stator core is likely to be broken or distorted by pressure of injection molding of the insulating resin material. Therefore, it is important to appropriately support the stator core in the mold so as to perform positioning.
[0004] For example, in Patent Document 1, when the stator core is set in the mold, both ends (shoe side and core back side) of a tooth portion and a center portion of the tooth portion are supported by the mold, whereby deformation of the core is suppressed and the thickness of the insulator is uniformed. In Patent Document 2, a pressure against the resin injection pressure is applied from an upper pressing die, whereby occurrence of breakage and distortion of the stator core is suppressed.

CITATION LIST
PATENT DOCUMENT
[0005] Patent Document 1: Japanese Laid-Open Patent
Publication No. 2008-278684
Patent Document 2: Japanese Laid-Open Patent Publication No. 2000-125524
SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0006] In the case of the conventional rotating electric machines, if the rotating electric machine is attempted to be further downsized, the shape of the insulator is constrained due to the presence of a mold reception portion of the mold for integral molding of the insulator, thus causing a problem that the space for coils is reduced.
[0007] The present invention has been made to solve the above problem, and an object of the present invention is to provide a rotating electric machine stator and a rotating electric machine stator manufacturing method that enable size reduction of a rotating electric machine by reducing constraint on the shape of an insulator.
SOLUTION TO THE PROBLEMS
[0008] A rotating electric machine stator according to the

present invention includes: a stator core formed by stacking a plurality of sheet materials in an axial direction; a coil; and an insulator insulating the stator core and the coil from each other. The stator core has a plurality of magnetic pole pieces and at least one yoke piece with a structure in which the yoke piece is formed between at least one pair of the magnetic pole pieces adjacent to each other in a circumferential direction among the plurality of magnetic pole pieces, and ends in the circumferential direction of the magnetic pole pieces and the yoke piece are bendably joined to each other to form an annular shape. Each magnetic pole piece has a first back yoke portion and a tooth portion protruding toward a radially inner side from the first back yoke portion. The yoke piece has a second back yoke portion. The first back yoke portion and the second back yoke portion form a back yoke portion serving as an outer circumferential portion of the stator core. The coil is formed by winding a wire around the tooth portion with the insulator therebetween.
A method for manufacturing the rotating electric machine stator configured as described above, according to the present invention, includes: a first step of stacking, in the axial direction, a plurality of the sheet materials stamped as the stator core in a straight shape in which the circumferential direction of the first back yoke portions of the magnetic pole pieces and the circumferential direction of

the second back yoke portion of the yoke piece are aligned; a second step of, using at least parts of both end surfaces in the axial direction of the yoke piece as mold reception portions, placing the stator core in the straight shape into a mold and injecting an insulating material into the mold to mold the insulator integrally with the stator core; a third step of winding the wire around each tooth portion of the stator core in the straight shape with the insulator therebetween, to form the coil; and a fourth step of bending ends in the circumferential direction of the first back yoke portion of each magnetic pole piece and the second back yoke portion of the yoke piece of the stator core in the straight shape to which the coil has been formed, so as to form the stator core into an annular shape.
EFFECT OF THE INVENTION
[0009] The rotating electric machine stator and the rotating electric machine stator manufacturing method according to the present invention enable size reduction of a rotating electric machine by reducing constraint on the shape of an insulator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] [FIG. 1] FIG. 1 is a top view showing the
structure of a rotating electric machine stator according to

embodiment 1 of the present invention.
[FIG. 2] FIG. 2 illustrates a method for manufacturing the stator shown in FIG. 1.
[FIG. 3] FIG. 3 illustrates the method for manufacturing the stator shown in FIG. 1.
[FIG. 4] FIG. 4 illustrates the method for manufacturing the stator shown in FIG. 1.
[FIG. 5] FIG. 5 illustrates the method for manufacturing the stator shown in FIG. 1.
[FIG. 6] FIG. 6 is a flowchart illustrating the method for manufacturing the stator shown in FIG. 1.
[FIG. 7] FIG. 7 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 1 of the present invention.
[FIG. 8] FIG. 8 illustrates the method for manufacturing the other rotating electric machine stator shown in FIG. 7.
[FIG. 9] FIG. 9 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 1 of the present invention.
[FIG. 10] FIG. 10 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 1 of the present invention.
[FIG. 11] FIG. 11 is a top view showing the structure of a rotating electric machine stator according to

embodiment 2 of the present invention.
[FIG. 12] FIG. 12 illustrates a method for manufacturing the stator shown in FIG. 11.
[FIG. 13] FIG. 13 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 2 of the present invention.
[FIG. 14] FIG. 14 illustrates the method for manufacturing the other rotating electric machine stator shown in FIG. 13.
[FIG. 15] FIG. 15 illustrates the method for manufacturing the other rotating electric machine stator shown in FIG. 13.
[FIG. 16] FIG. 16 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 2 of the present invention.
[FIG. 17] FIG. 17 illustrates the method for manufacturing the other rotating electric machine stator shown in FIG. 16.
[FIG. 18] FIG. 18 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 2 of the present invention.
[FIG. 19] FIG. 19 illustrates the method for manufacturing the other rotating electric machine stator shown in FIG. 18.
[FIG. 20] FIG. 20 illustrates a method for

manufacturing another rotating electric machine stator according to embodiment 2 of the present invention.
[FIG. 21] FIG. 21 illustrates the method for manufacturing the other rotating electric machine stator shown in FIG. 20.
[FIG. 22] FIG. 22 illustrates the method for manufacturing the other rotating electric machine stator shown in FIG. 20.
[FIG. 23] FIG. 23 illustrates a method for manufacturing a rotating electric machine stator according to embodiment 3 of the present invention.
[FIG. 24] FIG. 24 is a flowchart illustrating the method for manufacturing the rotating electric machine stator according to embodiment 3 of the present invention.
[FIG. 25] FIG. 25 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 3 of the present invention.
[FIG. 26] FIG. 26 is a top view showing the structure of a rotating electric machine stator according to embodiment 4 of the present invention.
[FIG. 27] FIG. 27 illustrates a method for manufacturing the stator shown in FIG. 26.
[FIG. 28] FIG. 28 is a top view showing an example of a rotating electric machine stator in a comparative example.

[FIG. 29] FIG. 29 illustrates a method for manufacturing the rotating electric machine stator in the comparative example shown in FIG. 28.
[FIG. 30] FIG. 30 is a top view showing an example of a rotating electric machine stator in another comparative example.
[FIG. 31] FIG. 31 is a top view showing the structure of another rotating electric machine stator according to embodiment 1 of the present invention.
[FIG. 32] FIG. 32 is a top view showing the structure of a rotating electric machine stator according to embodiment 5 of the present invention.
[FIG. 33] FIG. 33 is a sectional view showing the structure of the stator shown in FIG. 32.
[FIG. 34] FIG. 34 is a flowchart illustrating a method for manufacturing the stator shown in FIG. 32.
[FIG. 35] FIG. 35 is a top view showing the structure of another rotating electric machine stator according to embodiment 5 of the present invention.
[FIG. 36] FIG. 36 is a sectional view showing the structure of the other stator shown in FIG. 35.
[FIG. 37] FIG. 37 is a top view showing the structure of another rotating electric machine stator according to embodiment 1 of the present invention.
[FIG. 38] FIG. 38 is a top view showing the

structure of another rotating electric machine stator according to embodiment 1 of the present invention.
DESCRIPTION OF EMBODIMENTS [0011] Embodiment 1
Hereinafter, embodiments of the invention of the present disclosure will be described. FIG. 1 is a top view showing the structure of a rotating electric machine stator according to embodiment 1 of the present invention. FIG. 2 to FIG. 5 illustrate a method for manufacturing the stator shown in FIG. 1. FIG. 2 illustrates blanking of a thin sheet for forming a sheet material constituting a stator core. FIG. 3 illustrates a state after an insulator is molded integrally with the stator core. FIG. 4 illustrates a state in which a wire is wound around the stator core with which the insulator shown in FIG. 3 is integrally molded. FIG. 5 illustrates a state in which the stator core provided with the coil shown in FIG. 4 is formed into an annular shape.
[0012] FIG. 6 is a flowchart illustrating the method for manufacturing the stator shown in FIG. 1. FIG. 7 and FIG. 8 illustrate a method for manufacturing another rotating electric machine stator according to embodiment 1 of the present invention. FIG. 7 illustrates a state after an insulator is molded integrally with a stator core. FIG. 8 shows the structure of a mold for forming the insulator shown

in FIG. 7, and shows a state in which the stator core in a straight shape is placed.
[0013] FIG. 9 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 1 of the present invention. FIG. 10 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 1 of the present invention. FIG. 9 and FIG. 10 each illustrate a state after an insulator is molded integrally with a stator core. FIG. 31 is a top view showing the structure of another rotating electric machine stator according to embodiment 1 of the present invention. In the following description, directions with respect to the rotating electric machine stator 1 are referred to as circumferential direction Z, axial direction Y, radial direction X, radially inner side XI, and radially outer side X2. The axial direction Y is the same direction as the rotational axis of the stator 1. The axial direction Y is shown in FIG. 14 or FIG. 20 in the following embodiments. [0014] In FIG. 1, the rotating electric machine stator 1 includes a stator core 2, an insulator 3, and a coil 4. The stator core 2 is formed by stacking a plurality of sheet materials 10 which are thin sheets, in the axial direction Y. The stator core 2 is formed by a plurality of magnetic pole pieces 5 and a plurality of yoke pieces 6 being alternately arranged in an annular shape. Here, an example in which four

magnetic pole pieces 5 and four yoke pieces 6 are used is shown.
[0015] Although an example in which the stator core 2 is formed by a plurality of magnetic pole pieces 5 and a plurality of yoke pieces 6 being alternately arranged in an annular shape is shown here, the structure thereof is not limited thereto. The stator core may have a plurality of magnetic pole pieces and at least one yoke piece with a structure in which the yoke piece is formed between at least one pair of magnetic pole pieces adjacent to each other in the circumferential direction among the plurality of magnetic pole pieces, and ends in the circumferential direction of the magnetic pole pieces and the yoke piece(s) are bendably joined to each other to form an annular shape. In such a case, the other configurations may be made in the same manner as in the present embodiment 1.
[0016] Each magnetic pole piece 5 has a first back yoke portion 51 and a tooth portion 52. The first back yoke portion 51 is formed to extend in the circumferential direction Z. Therefore, the long-side direction Z of the first back yoke portion 51 corresponds to the circumferential direction Z. The tooth portion 52 is formed to protrude toward the radially inner side XI from the center position in the circumferential direction Z of the first back yoke portion 51. Therefore, the long-side direction X of the

tooth portion 52 is the same direction as the radial direction X.
[0017] The present embodiment 1 shows an example in which the long-side direction Z of the first back yoke portion 51 is the same direction as the circumferential direction Z and the long-side direction X of the tooth portion 52 is the same direction as the radial direction X. However, without limitation thereto, a configuration in which the long-side direction Z of the first back yoke portion 51 is the same direction as the radial direction X and the long-side direction X of the tooth portion 52 is the same direction as the circumferential direction Z, is also conceivable. In such a case, the other configurations may be made in the same manner as in the present embodiment 1.
[0018] Each yoke piece 6 has a second back yoke portion 61. The second back yoke portion 61 is formed to extend in the circumferential direction Z, as in the first back yoke portion 51. Therefore, the long-side direction Z of the second back yoke portion 61 is the same direction as the circumferential direction Z. A back yoke portion 7 which is the outer circumferential portion of the stator core 2 is formed by the first back yoke portion 51 and the second back yoke portion 61.
[0019] Of the yoke pieces 6, at least one yoke piece 6 has a division part 60. The division part 60 may be formed at an

end in the circumferential direction Z of the one yoke piece 6, or at any position in the circumferential-direction-Z range of the yoke piece 6. Here, as an example, the yoke piece 6 is divided at the center position in the circumferential direction Z. The division part 60 is not limited to this position, but may be set at another position, e.g., as shown in FIG. 31, the division part 60 may be formed at the border part between the yoke piece 6 and the magnetic pole piece 5, i.e., an end in the circumferential direction Z of the yoke piece 6. Here, an example in which the division part 60 is provided to one yoke piece 6 is shown. However, without limitation thereto, the division parts 60 may be formed in two yoke pieces 6, respectively. At the division part 60, a joining projection 68 is formed on one side and a joining recess 69 is formed on the other side. The joining is made by the joining projection 68 and the joining recess 69 being fitted to each other.
[0020] In the stator core 2, ends in the circumferential direction Z of the first back yoke portion 51 of the magnetic pole piece 5 and the second back yoke portion 61 of the yoke piece 6 that are adjacent to each other in the circumferential direction Z, are jointed to each other via a bendable thin portion 21. Thus, the first back yoke portion 51 is on one side with respect to the center in the circumferential direction Z of the thin portion 21, and the

second back yoke portion 61 is on the other side. [0021] The insulator 3 is formed so as to cover each magnetic pole piece 5 and so as not to cover any yoke piece 6. The insulator 3 covers circumferential side surfaces 56 in the circumferential direction Z of the tooth portion 52 of the magnetic pole piece 5, and both end surfaces 53 on the upper and lower sides in the axial direction Y of the magnetic pole piece 5. The insulator 3 is not formed at the joining part between the first back yoke portion 51 of the magnetic pole piece 5 and the second back yoke portion 61 of the yoke piece 6, and in the vicinity of the joining part. In addition, the insulator 3 is not formed on an outer side surface 54 on the radially outer side X2 of the first back yoke portion 51, and an inner side surface 55 on the radially inner side XI of the tooth portion 52. In addition, the insulator 3 does not cover both end surfaces 63 on the upper and lower sides in the axial direction Y of each yoke piece 6 at all.
[0022] Since the insulator 3 is formed by integral molding with the stator core 2, the insulator 3 is made of an insulating material resin used for insert molding. Specifically, any resin that allows injection molding may be used, and may be selected on the basis of heat resistance, resin shrinkage rate, resin fluidity, and the like so as to ensure, at a required dimension accuracy, that the insulator

3 can withstand a load when a wire is wound, and can retain the coil 4. For example, so-called engineering plastic such as polyphenylene sulfide resin (PPS resin), liquid crystal polymer resin (LCP resin), or polyacetal resin (POM resin), is desirable. The coil 4 is formed by winding a wire around the tooth portion 52 with an insulator 3 therebetween. [0023] In the following description, the long-side direction of the first back yoke portion 51 and the second back yoke portion 61 in the top view in FIG. 1 corresponds to the circumferential direction Z, and therefore may be referred to as the long-side direction Z of the first back yoke portion 51 and the second back yoke portion 61. In addition, the long-side direction of the tooth portion 52 in the top view in FIG. 1 corresponds to the radial direction X, and therefore may be referred to as the long-side direction X of the tooth portion 52. In the drawings other than the drawings showing a mold, parts where the insulators are formed are indicated by hatching.
[0024] A method for manufacturing the rotating electric machine stator 1 according to embodiment 1 configured as described above will be described with reference to the flowchart in FIG. 6. First, as shown in FIG. 2, sheet materials 10 (here, two sheet materials 10) for forming the stator core 2 are stamped by blanking from a thin sheet 11 formed of an electromagnetic steel sheet, for example. Each

sheet material 10 is formed in a straight shape in which the long-side direction Z of the first back yoke portion 51 of each magnetic pole piece 5 and the long-side direction Z of the second back yoke portion 61 of each yoke piece 6 coincide with each other and the magnetic pole pieces 5 and the yoke pieces 6 are arranged alternately. At this time, in order not to cause waste in the thin sheet 11, the two sheet materials 10 are arranged in parallel such that their tooth portions 52 are set in directions opposite to each other and each tooth portion 52 of one sheet material 10 is located between the tooth portions 52 of the other sheet material 10.
[0025] Then, the two sheet materials 10 arranged in the thin sheet 11 are stamped, and a predetermined number of the straight-shape sheet materials 10 are stacked and fixed by swaging (not shown). Then, the stator core 2 in a straight shape is formed by the plurality of magnetic pole pieces 5 and the plurality of yoke pieces 6. Thus, a stamping step as a first step is performed (step ST1 in FIG. 6).
[0026] Next, using, as mold reception portions, at least parts of both end surfaces 63 in the axial direction Y of each yoke piece 6, here, the entireties of both end surfaces 63, the stator core 2 in a straight shape is placed in a mold 8. The placement step for the mold 8 will be described later. Then, an insulating material is injected into the cavity in the mold 8 to mold the insulators 3 integrally with the

stator core 2. Thus, an insulator integral molding step as a second step is performed (step ST2 in FIG. 6). Then, the straight-shape stator core 2 with which the insulators 3 are integrally molded as shown in FIG. 3 is formed. [0027] At this time, each insulator 3 is not formed on both end surfaces 63 in the axial direction Y of the yoke piece 6 serving as the mold reception portions. In contrast, the insulator 3 is formed on both end surfaces 53 on the upper and lower sides in the axial direction Y of the magnetic pole piece 5. In addition, the insulator 3 is formed on the circumferential side surfaces 56 in the circumferential direction Z of the tooth portion 52. On the other hand, the insulator 3 is not formed on the outer side surface 54 on the radially outer side X2 of the first back yoke portion 51, and the inner side surface 55 on the radially inner side XI of the tooth portion 52. [0028] Next, the stator core 2 in a straight shape is set on a winding machine in a state in which the long-side direction Z of the first back yoke portion 51 of each magnetic pole piece 5 coincides with the long-side direction Z of the second back yoke portion 61 of each yoke piece 6. That is, winding work is performed for the stator core 2 in a straight shape that is in a state when the stator core 2 has been stamped by a press machine. The winding machine has a flyer 45 for feeding and winding a wire. The flyer 45 is

placed such that a rotational axis F thereof coincides with the long-side direction X of the tooth portion 52 of each magnetic pole piece 5.
[0029] Then, while sliding operation is performed in a direction coinciding with the long-side direction X of the tooth portion 52 of the magnetic pole piece 5, a wire is wound around the tooth portion 52, to form the coil 4. Then, after formation of the coil 4 on the tooth portion 52 of one magnetic pole piece 5 is finished, the flyer 45 is slid in the long-side direction Z of the first back yoke portion 51, so as to be moved until the rotational axis F of the flyer 45 is opposed to the tooth portion 52 of another adjacent magnetic pole piece 5, and then wire winding operation is performed again. At this time, the above operation is performed without cutting the winding finish part of the coil
4 at the tooth portion 52 of the magnetic pole piece 5 that has been previously formed. Therefore, the wire striding between the tooth portions 52 serves as a jumper wire 42. Such a wire winding operation is repeated to form the coils 4 around the tooth portions 52 of all the magnetic pole pieces
5 as shown in FIG. 4. Thus, a winding step as a third step is finished (step ST3 in FIG. 6).
[0030] Next, after the coils 4 are formed around the tooth portions 52 of all the magnetic pole pieces 5, as shown in FIG. 5, the inner side surfaces 55 of the tooth portions 52

of the magnetic pole pieces 5 are sequentially pressed against a columnar core metal 88 so that the stator core 2 in a straight shape is bent and closed into an annular shape. Then, the joining projection 68 and the joining recess 69 of the yoke piece 6 are fitted to each other. After the fitting, the fitted parts are integrated by being joined by welding means such as tungsten inert gas (TIG) welding from the radially outer side X2. Thus, a core closing step as a fourth step is finished (step ST4 in FIG. 6). At this time, the joining is performed with the joining projection 68 and the joining recess 69 abutting on each other, whereby position displacement in the radial direction X at the time of abutting can be suppressed and thus the roundness of the stator 1 can be improved.
[0031] Next, the step for placing the straight-shape stator core 2 in the mold 8 shown above will be described. The stator core 2 shown above is formed by four magnetic pole pieces 5 and four yoke pieces 6. However, the numbers of the magnetic pole pieces 5 and the yoke pieces 6 are not limited thereto. Here, as shown in FIG. 7, the case where the stator core 2 is formed by six magnetic pole pieces 5 and six yoke pieces 6 will be described. It is noted that, since the number of tooth portions 52 is increased to six, torque pulsation that occurs in the rotating electric machine can be suppressed as compared to the case of providing four tooth

portions 52 shown above. The same parts as those in embodiment 1 shown above are denoted by the same reference characters and the description thereof is omitted. [0032] In the case of forming the stator core 2 with which the insulator 3 is integrally molded as shown in FIG. 7, the stator core 2 in a straight shape is placed in the mold 8 as shown in FIG. 8. In FIG. 8, for convenience sake, the parts where the magnetic pole pieces 5 are placed are indicated by dotted lines, and the parts where the yoke pieces 6 are placed are indicated by solid lines. The mold 8 is composed of a fixed die 81, a movable die 82, and core dies 83. [0033] As shown in FIG. 8, the entire areas of both end surfaces 63 in the axial direction Y of each yoke piece 6 serve as mold reception portions with respect to the core dies 83, and are sandwiched between the core dies 83, whereby the stator core 2 can be supported in the axial direction Y in the mold 8. Therefore, at the parts where the yoke pieces 6 are placed in the mold 8, there is no cavity and thus the insulator 3 is not formed. The mold 8 is not limited to the configuration of having the fixed die 81, the movable die 82, and the core dies 83 as described above, but may have any configuration that allows the insulator 3 to be formed in the same manner.
[0034] In addition, the inner side surfaces 55 on the radially inner side XI of the magnetic pole pieces 5 are

supported in contact with the fixed die 81. The outer side surfaces 54 on the radially outer side X2 of the magnetic pole pieces 5 and the yoke pieces 6 are supported in contact with the movable die 82. Therefore, the insulators 3 are not formed on the inner side surfaces 55 on the radially inner side XI of the magnetic pole pieces 5 and the outer side surfaces 54 on the radially outer side X2 of the magnetic pole pieces 5.
[0035] Next, the case where the stator core 2 in embodiment 1 is formed by the magnetic pole pieces 5 and the yoke pieces 6, and the case of a comparative example shown in FIG. 28 to FIG. 30, will be described through comparison therebetween. In the comparative example, the stator core is formed by only magnetic pole pieces 105. In FIG. 28, each magnetic pole piece 105 has a back yoke portion 151 and a tooth portion 152 protruding toward the radially inner side XI from the back yoke portion 151. As in embodiment 1, the magnetic pole piece 105 is formed by stacking a plurality of sheet materials in the axial direction Y. Then, an insulator 103 is molded integrally with the magnetic pole piece 105. [0036] FIG. 29 shows a mold 108 for forming the insulator 103. In FIG. 29, the mold 108 is composed of a fixed die 181, a movable die 182, and core dies 183. In order to sandwich the magnetic pole piece 105 in the axial direction Y so as to support the same, exposed parts 156, 157 in partial areas in

the circumferential direction Z on both of the radially outer side X2 and the radially inner side XI of both end surfaces 153 in the axial direction Y of the magnetic pole piece 105 are supported as mold reception portions.
[0037] Therefore, the insulator 103 molded integrally with the magnetic pole piece 105 by the mold 108 is formed such that, as shown in FIG. 28, of both end surfaces 153 in the axial direction Y of the magnetic pole piece 105, partial areas in the circumferential direction Z on both of the radially outer side X2 and the radially inner side XI, i.e., the areas corresponding to the exposed parts 156, 157 are not covered but are exposed.
[0038] In the shape of the insulator 103, a width W2 is needed for ensuring a strength and a width needed for terminal insertion and the like. A width W3 is needed for ensuring a strength for preventing the insulator 103 from collapsing due to the tension of a wound coil. The remaining width W4 other than the ensured widths W2, W3 is used for the part where the coil is formed.
[0039] On the other hand, in the case where it is not necessary to provide a mold reception portion for a mold to both end surfaces 153 of the magnetic pole piece 105, the insulator 103 is formed as shown in FIG. 30. Even in this case, the required lengths of the width W2 and the width W3 do not differ. Therefore, if the width Wl in the radial

direction X of the magnetic pole piece 105 is the same, a width W5 for the part where a coil is formed can be ensured to be greater than the width W4 shown above in FIG. 28. In the case of FIG. 30, it is impossible to retain the magnetic pole piece 105 by the mold, and therefore the insulator 103 cannot be integrally molded.
[0040] However, in the present embodiment 1, the yoke piece 6 between the magnetic pole piece 5 and the magnetic pole piece 5 serves as a mold reception portion for the mold 8. Therefore, even in the case of molding the insulator 3 integrally with the magnetic pole piece 5, it is possible to ensure the part for forming the coil 4 as in the case of FIG. 30.
[0041] In the rotating electric machine stator and the rotating electric machine stator manufacturing method according to embodiment 1 configured as described above, the stator core is formed in a divided manner by a plurality of magnetic pole pieces and a plurality of yoke pieces, and the insulators are molded integrally with the stator core so as to cover areas excluding the entireties of both end surfaces in the axial direction of each yoke piece. Therefore, the entire surfaces of both end surfaces in the axial direction of each yoke piece can be used as mold reception portions for the mold for forming the insulator. Thus, in the mold, the entireties of both end surfaces in the axial direction of

each yoke piece can be sandwiched in the axial direction, whereby breakage or deformation of the stator core due to the resin pressure at the time of integral molding can be suppressed. Accordingly, the clearance between the mold and the stator core is kept uniform, the thickness of the resin material for forming the insulator can be uniformed, and occurrence of unfilled part can be prevented.
[0042] In addition, since a mold reception portion for the mold is not present on the magnetic pole piece, a larger area for forming a coil can be ensured as compared to the conventional case. Therefore, the coil can be wound at a higher density and a thicker coil can be wound with the same number of turns, leading to size reduction and increased efficiency of the rotating electric machine. [0043] In addition, since the insulator is molded integrally with the stator core, a step for mounting the insulator is not performed, and thus the stator manufacturing process can be simplified.
[0044] The stator core is formed in a divided manner by a plurality of magnetic pole pieces and a plurality of yoke pieces, and the magnetic pole pieces and the yoke pieces are formed so as to be joined to each other. Therefore, at the time of winding a wire on the stator core in a straight shape to form a coil, it is possible to naturally avoid interference between the winding machine and the stator core.

Thus, it becomes possible to increase the speed of winding and perform the winding regularly, leading to improvement in productivity, improvement in efficiency of the rotating electric machine, and size reduction of the rotating electric machine.
[0045] In the above embodiment 1, the example in which the plurality of magnetic pole pieces 5 and the plurality of yoke pieces 6 are alternately arranged and formed in an annular shape, has been shown. However, without limitation thereto, examples as shown in FIG. 37 and FIG. 38 are conceivable. FIG. 37 shows an example in which a plurality of yoke pieces 6 are formed between one pair of magnetic pole pieces 5. FIG. 38 shows an example in which a plurality of yoke pieces 6 are formed between every pair of magnetic pole pieces 5. The number of yoke pieces 6 between one pair of magnetic pole pieces 5 is not limited to these examples. In any case, the other configurations may be made in the same manner as in the present embodiment 1, and the same effects can be provided. [0046] In the above embodiment 1, an example in which the insulator 3 covers the entireties of both end surfaces 53 in the axial direction Y of the magnetic pole piece 5 (except the joining parts), has been shown. However, without limitation thereto, for example, as shown in FIG. 9, it is conceivable that the insulator 3 does not cover partial areas in the circumferential direction Z on the radially outer side

X2 of both end surfaces 53 in the axial direction Y of each magnetic pole piece 5 so that the partial areas are exposed to form exposed parts 540. Alternatively, as shown in FIG. 10, it is conceivable that the insulator 3 does not cover partial areas in the circumferential direction Z on the radially inner side XI of both end surfaces 53 in the axial direction Y of each magnetic pole piece 5 so that the partial areas are exposed to form exposed parts 550. [0047] In the case where the insulator 3 is formed such that partial areas in the circumferential direction Z on at least one of the radially outer side X2 and the radially inner side XI of both end surfaces 53 in the axial direction Y of each magnetic pole piece 5 are not covered but are exposed, the exposed parts 540 or the exposed parts 550 can be set as mold reception portions for the mold. Thus, it is possible to reinforce retention of the stator core 2 in the mold in the axial direction Y, as compared to embodiment 1 shown above.
[0048] Therefore, breakage or deformation of the stator core due to the resin pressure at the time of integral molding for the insulator can be further suppressed, whereby the clearance between the mold and the stator core is kept further uniform, the thickness of the resin is further uniformed, and occurrence of unfilled part can be further suppressed. Such a configuration is effective for the case

where the receiving force of the stator core is more needed as compared to the above embodiment 1, depending on the type resin material and the molding condition thereof, for example.
[0049] The example in which the insulator is formed such that partial areas in the circumferential direction on at least one of the radially outer side and the radially inner side of both end surfaces in the axial direction of each magnetic pole piece are not covered but are exposed, is applicable also to the following embodiments in the same manner, and the description thereof is omitted as appropriate.
[0050] Embodiment 2
The above embodiment 1 has shown an example in which the insulators 3 are not formed on the entire areas of the yoke pieces 6, i.e., the insulator 3 does not cover both end surfaces 63 on the upper and lower sides in the axial direction Y of each yoke piece 6 at all. The present embodiment 2 will show an example in which an insulator 30 is formed so as to cover partial areas in the circumferential direction Z on the radially inner side XI of both end surfaces 63 in the axial direction Y of each yoke piece 6, and a partial area of the side surface on the radially inner side XI of the yoke piece 6, that is, the insulator 30 covers areas excluding at least partial areas of both end surfaces 63 in the axial direction Y of each yoke piece 6. [0051] FIG. 11 is a top view showing the structure of a

rotating electric machine stator according to embodiment 2 of the present invention. FIG. 12 illustrates a method for manufacturing the stator shown in FIG. 11. FIG. 13 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 2 of the present invention. FIG. 14 and FIG. 15 illustrate the method for manufacturing the other rotating electric machine stator shown in FIG. 13. FIG. 16 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 2 of the present invention. [0052] FIG. 17 illustrates the method for manufacturing the other rotating electric machine stator shown in FIG. 16. FIG. 18 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 2 of the present invention. FIG. 19 illustrates the method for manufacturing the other rotating electric machine stator shown in FIG. 18. FIG. 20 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 2 of the present invention. FIG. 21 and FIG. 22 illustrate the method for manufacturing the other rotating electric machine stator shown in FIG. 20. [0053] In FIG. 11, the same parts as those in the above embodiment 1 are denoted by the same reference characters and the description thereof is omitted. The insulator 30 is formed so as to cover partial areas in the circumferential

direction Z on the radially inner side XI of both end surfaces 63 in the axial direction Y of each yoke piece 6, and a partial area of the inner side surface 64 on the radially inner side XI of the yoke piece 6. In formation of the insulators 3, 30, regarding the mold, as compared to the above embodiment 1, parts other than partial areas in the circumferential direction Z on the radially inner side XI of both end surfaces 63 in the axial direction Y of each yoke piece 6 are used as mold reception portions, whereby the insulator 3 and the insulator 30 are formed.
[0054] Therefore, as shown in FIG. 11, as compared to the above embodiment 1, even if the coil 4 is formed to reach a space in the circumferential direction Z on the yoke piece 6 side, the insulator 30 formed on the yoke piece 6 ensures insulation. Thus, it is possible to ensure a large area for forming the coil 4. Accordingly, with the stator core 2 having the same shape, it is possible to provide the rotating electric machine stator 1 having the coils 4 with increased density.
[0055] In a downsized rotating electric machine, it is difficult to ensure a space where the jumper wire 42 is placed. However, in the present embodiment 2, since the insulator 30 is formed on each adjacent yoke piece 6, the jumper wire 42 can be placed at this part, and thus the space therefor can be ensured easily. Further, the insulator 30 is

molded integrally between the plurality of layers in the axial direction Y of the yoke piece 6, and thus the resin entering between the layers provides an anchor effect, thereby preventing the insulator 30 from being displaced or detached even when a tension is applied at the time of winding a wire.
[0056] As another example, as shown in FIG. 15, an opening 67 which opens in the axial direction Y is formed in several layers at the both end surfaces 63 in the axial direction Y of each yoke piece 6. Then, as shown in FIG. 13 and FIG.: 14, the insulator 30 is formed so as to fill the inside of the opening 67. Thus, since the insulator 30 fills the opening 67, the insulator 30 formed on the yoke piece 6 is prevented from being displaced or detached from the yoke piece 6 even when a tension is applied at the time of winding a wire. [0057] From the perspective of the strength of the insulator 30, it is also conceivable that the opening 67 is formed so as to penetrate between both end surfaces 63 in the axial direction Y of each yoke piece 6. However, from the perspective of ensuring a magnetic path for a rotating electric machine, as shown above (in particular, see FIG. 14), the configuration in which the opening 67 is formed in the axial direction Y in several layers at both end surfaces 63 in the axial direction Y of each yoke piece 6 is considered to be more excellent.

[0058] As another example, as shown in FIG. 17, a projection 65 is formed on the inner side surface 64 on the radially inner side XI of each yoke piece 6. Then, as shown in FIG. 16, the insulator 30 is formed so as to cover the projection 65. Thus, the projection 65 formed on the yoke piece 6 prevents the insulator 30 formed on the yoke piece 6 from being displaced or detached from the yoke piece 6 even when a tension is applied at the time of winding a wire. [0059] As another example, as shown in FIG. 19, a recess 66 is formed in the inner side surface 64 on the radially inner side XI of each yoke piece 6. Then, as shown in FIG. 18, the insulator 30 is formed so as to cover the recess 66. Thus, the recess 66 formed in the yoke piece 6 prevents the insulator 30 formed on the yoke piece 6 from being displaced or detached from the yoke piece even when a tension is applied at the time of winding a wire. It is noted that, from the perspective of ensuring a magnetic path for a rotating electric machine, the configuration in which the projection 65 is formed on the yoke piece 6 is considered to be more excellent than the configuration in which the recess 66 is formed.
[0060] As another example, as shown in FIG. 20 to FIG. 22, the insulator 30 has a protrusion 31 protruding in the axial direction Y, at one end surface 63 in the axial direction Y of each yoke piece 6 that has no division part 60. Then, as

shown in FIG. 20, the jumper wire 42 passed between the tooth portions 52 adjacent to each other in the circumferential direction Z of the coils 4 is hooked on the protrusion 31. Thus, since the jumper wire 42 can be hooked on the protrusion 31 formed at the yoke piece 6, it is not necessary to hook the jumper wire on the insulator on the corresponding tooth portion as in the case of the conventional stator not having the yoke piece 6. Therefore, as compared to the conventional case, it is possible to ensure the part (protrusion 31) where the jumper wire 42 is placed, even in a downsized rotating electric machine stator. Accordingly, the jumper wire 42 can be placed at high speed, leading to improvement in productivity.
[0061] The reason why the protrusion 31 is not formed at the yoke piece 6 having no division part 60 is because, as shown in FIG. 22, the yoke piece 6 having the division part 60 is a part where winding is started and finished, and thus is not a part where the jumper wire 42 is placed. [0062] The rotating electric machine stator and the rotating electric machine stator manufacturing method according to embodiment 2 configured as described above provide the same effects as those in the above embodiment 1, and in addition, provides the following effects. That is, the stator core is formed in a divided manner by a plurality of magnetic pole pieces and a plurality of yoke pieces, and

the insulator is formed by integral molding on the stator core so as to cover areas excluding at least partial areas of both end surfaces in the axial direction of each yoke piece. Therefore, partial areas of both end surfaces in the axial direction of each yoke piece can be used as mold reception portions for the mold for forming the insulator. Thus, in the mold, partial areas of both end surfaces in the axial direction of each yoke piece can be sandwiched in the axial direction, whereby breakage and deformation of the stator core due to the resin pressure at the time of integral molding can be suppressed. Accordingly, the clearance between the mold and the stator core is kept uniform, the thickness of the resin material for forming the insulator can be uniformed, and occurrence of unfilled part can be prevented.
[0063] In addition, the insulator is formed so as to cover partial areas in the circumferential direction on the radially inner side of both end surfaces in the axial direction of each yoke piece and a partial area of the side surface on the radially inner side of the yoke piece, whereby, on the yoke piece, insulation of the jumper wire striding between the tooth portions is easily ensured. In addition, owing to the insulator formed on the yoke piece, the coil formed on the tooth portion of the magnetic pole piece can be formed so as to extend in the circumferential direction, and

thus it becomes possible to provide a rotating electric machine stator having coils with increased density.
[0064] In addition, since the yoke piece has a projection or a recess at the inner side surface on the radially inner side and the insulator is formed so as to cover the projection or the recess, the insulator formed on the yoke piece can be prevented from being displaced or detached from the yoke piece.
[0065] At both end surfaces in the axial direction of each yoke piece, an opening that opens in the axial direction is formed, and the insulator is formed so as to fill the inside of the opening. Therefore, the insulator formed on the yoke piece can be prevented from being displaced or detached from the yoke piece.
[0066] The insulator has a protrusion protruding in the axial direction, at one end surface in the axial direction of each yoke piece that has no division part, and a jumper wire passed between the tooth portions adjacent in the circumferential direction of the coils is hooked on the protrusion. Therefore, placement of the jumper wire is ensured and productivity is improved.
[0067] As compared to the conventional case, even in a downsized rotating electric machine stator, the jumper wire can be assuredly hooked and a large space for operating the winding machine can be ensured. Therefore, it is possible to

perform operation of forming a jumper wire at high speed, leading to improvement in productivity. In the case where the size of the rotating electric machine is excessively small, it is difficult to provide a space for placing the jumper wire itself. However, since the jumper wire may be hooked on the protrusion of each yoke piece, the space can be easily ensured.
[0068] The example in which the insulator is formed so as to cover areas excluding at least partial areas of both end surfaces in the axial direction of each yoke piece as shown in the present embodiment 2, is applicable also to the following embodiments in the same manner, and the description thereof is omitted as appropriate. [00 69] Embodiment 3
FIG. 23 illustrates a method for manufacturing a rotating electric machine stator according to embodiment 3 of the present invention. FIG. 24 is a flowchart illustrating the method for manufacturing the rotating electric machine stator according to embodiment 3 of the present invention. FIG. 25 illustrates a method for manufacturing another rotating electric machine stator according to embodiment 3 of the present invention. In the drawings, the same parts as those in the above embodiments are denoted by the same reference characters and the description thereof is omitted. [0070] In the present embodiment 3, an example in which a

receiving portion protruding outward of the stator core 2 is formed on at least one of the magnetic pole piece 5 and the yoke piece 6, will be described. As shown in FIG. 23, receiving portions 91, 92 protruding outward of the stator core 2 are formed on the magnetic pole piece 5. The receiving portion 91 is formed on the outer side surface 54 on the radially outer side X2 of the first back yoke portion 51. The receiving portions 92 are formed on both sides in the circumferential direction Z of the tooth portion 52. In order to facilitate removal of the receiving portions 91, 92 from the magnetic pole piece 5, the parts of the receiving portions 91, 92 that are in contact with the magnetic pole piece 5 are formed to be thin.
[0071] Next, the rotating electric machine stator manufacturing method according to embodiment 3 of the present invention will be described. First, as in the above embodiment 1, in a stamping step (step ST1 in FIG. 24), the receiving portion 91 and the receiving portions 92 are formed on each magnetic pole piece 5. Next, in an insulator integral molding step (step ST2 in FIG. 24), as in the above embodiment 1, both end surfaces 63 in the axial direction Y of the yoke piece 6 are used as mold reception portions for the mold, and in addition, the receiving portion 91 and the receiving portions 92 that have been previously formed are used as mold reception portions for the mold.

[0072] Therefore, the stator core 2 can be strongly held in the mold, whereby breakage and deformation of the stator core 2 due to the resin pressure at the time of integral molding for the insulator 3 can be suppressed. In addition, the clearance between the mold and the stator core is kept uniform, the thickness of the resin material is uniformed, and occurrence of unfilled part can be suppressed. By using the receiving portions 91, 92 provided outside, which do not form the stator core 2, it is possible to assuredly perform positioning of the stator core 2 in the mold and assuredly hold the stator core 2 in the mold even if the mold reception portions for the mold which are set on the magnetic pole piece 5 and the yoke piece 6 are reduced. Therefore, the size of the stator core 2 can be further reduced, and thus the rotating electric machine can be downsized.
[0073] Next, after the insulator integral molding step and before the winding step (step ST3 in FIG. 24), a removal step
(step ST10 in FIG. 24) of removing the receiving portions 91, 92 from the stator core 2 is performed. Thus, for example, as shown in FIG. 7, the stator core 2 that has no receiving portions 91, 92 and which is similar to that in the above embodiment 1, is formed. Then, subsequently, the same steps as those in the above embodiment 1 are performed to form the stator 1.
[0074] As another example, as shown in FIG. 25, a

receiving portion 93 protruding outward of the stator core 2 is formed on each yoke piece 6. The receiving portion 93 is formed on the outer side surface 62 on the radially outer side X2 of the second back yoke portion 61. In order to facilitate removal of the receiving portion 93 from the yoke piece 6, the part of the receiving portion 93 that is in contact with the yoke piece 6 is formed to be thin. In this way, the receiving portion 93 is further added as a mold reception portion for the mold, whereby the above effects can be further enhanced.
[0075] In FIG. 25, the example in which the receiving portions 91, 92, 93 are formed on the magnetic pole piece 5 and the yoke piece 6, has been shown. However, without limitation thereto, the receiving portion 93 may be formed on only the yoke piece 6. The locations and numbers of the receiving portions 91, 92, 93 to be formed are not limited to those shown above. As long as the receiving portions are provided outward of the stator core 2 and can be removed and the receiving portions serve as mold reception portions when placed in the mold, the same effects can be provided. [0076] In the rotating electric machine stator and the rotating electric machine manufacturing method according to embodiment 3 configured as described above, in the first step, a receiving portion protruding outward of the stator core is formed on at least one of the magnetic pole piece and the

yoke piece; in the second step, using the receiving portions as mold reception portions, the stator core in a straight shape is placed in the mold; and the removal step of removing the receiving portions from the stator core is performed after the second step and before the third step. Therefore, the receiving portion formed on at least one of the magnetic pole piece and the yoke piece and protruding outward of the stator core serves as a mold reception portion, whereby the stator core can be strongly held. Thus, breakage and deformation of the stator core due to the resin pressure at the time of integral molding for the insulator can be suppressed.
[0077] Accordingly, the clearance between the mold and the stator core is kept uniform, the thickness of the resin is uniformed, and occurrence of unfilled part can be prevented. In addition, by using, as mold reception portions, the receiving portions provided outside, it is possible to assuredly perform positioning of the stator core and assuredly hold the stator core even if the mold reception portions of the magnetic pole piece and the yoke piece are reduced. Therefore, the size of the stator core can be further reduced, leading to further size reduction of the rotating electric machine. In addition, since the receiving portions are subsequently removed, the shape of the stator core is not influenced in order to obtain the effects.

[007 8] Embodiment 4
FIG. 26 is a top view showing the structure of a rotating electric machine stator according to embodiment 4 of the present invention. FIG. 27 illustrates a method for manufacturing the stator shown in FIG. 26. In the drawings, the same parts as those in the above embodiments are denoted by the same reference characters and the description thereof is omitted. As shown in FIG. 27, when the stator core 2 is developed in a straight shape such that the long-side direction Z of the first back yoke portions 51 of the magnetic pole pieces 5 and the long-side direction Z of the second back yoke portions 61 of the yoke pieces 6 coincide with each other, a center point Q2 on the second back yoke portion 61 of each yoke piece 6 is located on the radially outer side X2 with respect to a center point Ql on the first back yoke portion 51 of each magnetic pole piece 5. As used herein, each center point Ql, Q2 refers to a point that is at the center in the circumferential direction Z (long-side direction Z) and at the center in the radial direction X. A line passing the center points Ql of the magnetic pole pieces 5 in the long-side direction Z is indicated as a center line H2.
[0079] When the stator core 2 in a straight shape as described above is formed into an annular shape as shown in FIG. 26 to form the stator 1, an extended line G from a seam

line 71 where the magnetic pole piece 5 and the yoke piece 6 abut on each other at an end in the circumferential direction Z does not pass a center point Q of the stator 1. At this time, an intersection P at which the extended lines G of the seam lines 71 adjacent in the circumferential direction Z intersect is located at a position distant toward the radially outer side X2 from the center point Q of the stator 1.
[0080] As shown in FIG. 27, during the work for winding a wire around each tooth portion 52, a turning plane Hi of the flyer 45 is located on the radially inner side XI with respect to the center line H2, and further, the second back yoke portion 61 of the yoke piece 6 is located on the radially outer side X2 with respect to the turning plane HI of the flyer 45. Therefore, it is ensured that the second back yoke portion 61 is prevented from interfering with the flyer 45. Thus, it becomes possible to easily perform regular winding around the tooth portion 52 and perform the winding at high speed. Further, since the coil 4 is formed at higher density, the rotating electric machine is expected to be further downsized.
[0081] The rotating electric machine stator according to embodiment 4 configured as described above provides the same effects as those in the above embodiments, and in addition, provides the following effects. That is, in the stator core

developed in a straight shape, the center point on the second back yoke portion of each yoke piece is located on the radially outer side with respect to the center point on the first back yoke portion of each magnetic pole piece. Therefore, the second back yoke portion does not interfere with the flyer, and the operation range of the flyer is not constrained. Thus, the coil can be easily formed, the coil can be wound at higher density, and a thicker coil can be wound with the same number of turns, leading to further size reduction and further efficiency enhancement of the rotating electric machine. [0082] Embodiment 5
In the case of the stator 1 shown above, if the heat dissipation effect of the stator 1 is low, it is necessary to take a measure such as increasing the heat dissipation area by increasing the size in the radial direction X of the stator 1, or providing another means such as a cooling fan. Accordingly, the case of solving such a problem will be described below. In the above embodiments, an example in which the process is performed until the core closing step (step ST4) to form the stator 1, has been shown. However, in the present embodiment 5, after the core closing step, the stator 1 is molded with a molding resin, to form a molding resin portion. The present embodiment is applicable in the same manner for all the above embodiments. Here, the

structure shown in FIG. 11 in the above embodiment 2 is used as an example.
[0083] FIG. 32 is a top view showing the structure of a rotating electric machine stator according to embodiment 5 of the present invention. FIG. 33 is a sectional top view showing the cross section in the radial direction X of the structure of the stator shown in FIG. 32. FIG. 34 is a flowchart illustrating a method for manufacturing the stator shown in FIG. 32. FIG. 35 is a top view showing the structure of another rotating electric machine stator according to embodiment 5 of the present invention. FIG. 3 6 is a sectional top view showing the cross section in the radial direction X of the structure of the other stator shown in FIG. 35. In the drawings, the part where the molding resin portion is formed is indicated by thick-line hatching. In FIG. 32 and FIG. 35, the part formed on the inner side with respect to the molding resin portion cannot be seen in actuality, but is shown in the drawings.
[0084] In the drawings, the same parts as those in the above embodiments are denoted by the same reference characters and the description thereof is omitted. A molding resin portion 300 covers the entireties of the coils 4, and also covers the entireties of the plurality of magnetic pole pieces 5 and the plurality of yoke pieces 6. As shown in FIG. 33, the molding resin portion 300 is formed so as to fill the

space between the coil 4 and the coil 4 in the circumferential direction Z. An outer side surface 301 on the radially outer side X2 of the molding resin portion 300 is formed on the radially outer side X2 with respect to the outer side surfaces 54 on the radially outer side X2 of the magnetic pole pieces 5 and the yoke pieces 6. An inner side surface 302 on the radially inner side XI of the molding resin portion 300 is formed with substantially the same dimension in the radial direction X as the inner side surfaces 55 on the radially inner side XI of the magnetic pole pieces 5. The molding resin portion 300 is made of, for example, polyphenylene sulfide resin (PPS resin), polyacetal resin (POM resin), or epoxy resin (EP resin). [0085] Next, a method for manufacturing the rotating electric machine stator according to embodiment 5 of the present invention will be described. First, as in the above embodiments, the process from the stamping step (step ST1 in FIG. 34) to the core closing step (step ST4 in FIG. 34) is performed to form the stator 1 as shown in, for example, FIG. 11. Next, the stator 1 formed as shown in FIG. 11 is placed into the resin molding mold, and is molded with a molding resin injected therein, to form the molding resin portion 300. Thus, a molding step as a fifth step is performed (step ST5 in FIG. 34). Then, the molded product is extracted from the resin molding mold, whereby the stator 1 as shown in FIG. 32

is formed.
[0086] The rotating electric machine stator and the rotating electric machine manufacturing method according to embodiment 5 configured as described above provide the same effects as those in the above embodiments. Further, since the coils which generate heat are covered with the molding resin portion, heat generated when the coils are energized is more easily transmitted through the molding resin portion so as to be dissipated, as compared to the above embodiments. Therefore, the stator can be downsized, and it is not necessary to provide another means such as a cooling fan needed for heat dissipation, and thus the cost is reduced. [0087] Further, since the shape of the coils formed by winding is retained by the molding resin portion, it is possible to prevent deformation of the shape of the coils due to vibration of the rotating electric machine during operation, vibration occurring when the stator is carried, or the like. Thus, contact of the coils with the magnetic pole pieces or the yoke pieces, which would occur due to deformation of the shape of the coils, can be prevented. [0088] Further, the molding resin portion prevents materials such as stator coolant, fuel, or oil used for operating the rotating electric machine from adhering to the coils, whereby deterioration of the coils can be suppressed. [0089] As another example of embodiment 5, as shown in FIG.

35, it is conceivable that a molding resin portion 310 covers all the coils 4 and covers a part of the plurality of magnetic pole pieces 5 and the plurality of yoke pieces 6. As shown in FIG. 35, the molding resin portion 310 is formed so as to fill the space between the coil 4 and the coil 4 in the circumferential direction Z. An outer side surface 311 on the radially outer side X2 of the molding resin portion 310 is located on the radially inner side XI with respect to the outer side surfaces 54 on the radially outer side X2 of the magnetic pole pieces 5 and the yoke pieces 6. An inner side surface 312 on the radially inner side XI of the molding resin portion 310 is formed with substantially the same dimension in the radial direction X as the inner side surfaces 55 on the radially inner side XI of the magnetic pole pieces 5.
[0090] As described above, the outer side surface 311 of the molding resin portion 310 is formed on the radially inner side XI with respect to the outer side surfaces 54 of the magnetic pole pieces 5 and the yoke pieces 6, and therefore, at the time of putting the stator 1 formed as shown in FIG. 11 into the resin molding mold, it is possible to place the stator 1 in the resin molding mold while pressing the outer side surfaces 54 of the magnetic pole pieces 5 and the yoke pieces 6. [0091] As described above, in the structure shown above in

FIG. 32, the outermost circumference of the stator is the outer side surface of the molding resin portion, whereas in the configuration shown in FIG. 35, the outermost circumference of the stator is the outer side surfaces of the magnetic pole pieces and the yoke pieces, and thus the size can be reduced. Further, in forming the molding resin portion, the outer side surfaces of the magnetic pole pieces and the yoke pieces can be used as support surfaces for the resin molding mold. Therefore, it is possible to stably form a molding resin portion in an optional shape. [0092] In the above embodiment 5, jumper wires passed between the tooth portions 52 adjacent in the circumferential direction Z of the coils 4 are not particularly shown. However, in the case where the jumper wires 42 as shown in FIG. 20 are formed, the jumper wires 42 may be covered with the molding resin portion 300, 310.
[0093] With such a configuration, in addition to the above effects, it is possible to prevent position displacement of the jumper wires due to vibration of the rotating electric machine during operation, vibration occurring when the stator is carried, or the like, because the positions of the jumper wires are fixed by the molding resin portion. Therefore, contact of the jumper wires with the magnetic pole pieces or the yoke pieces, which would occur due to position displacement of the jumper wires, can be prevented.

[0094] Further, the molding resin portion prevents materials such as stator coolant, fuel, or oil used for operating the rotating electric machine from adhering to the jumper wires, whereby deterioration of the jumper wires can be suppressed.
[0095] It is noted that, within the scope of the present invention, the above embodiments may be freely combined with each other, or each of the above embodiments may be modified or simplified as appropriate.

We Claim:
[1] A rotating electric machine stator comprising:
a stator core formed by stacking a plurality of sheet materials in an axial direction;
a coil; and
an insulator insulating the stator core and the coil from each other, wherein
the stator core has a plurality of magnetic pole pieces and at least one yoke piece with a structure in which the yoke piece is formed between at least one pair of the magnetic pole pieces adjacent to each other in a circumferential direction among the plurality of magnetic pole pieces, and ends in the circumferential direction of the magnetic pole pieces and the yoke piece are bendably joined to each other to form an annular shape,
each magnetic pole piece has a first back yoke portion and a tooth portion protruding toward a radially inner side from the first back yoke portion,
the yoke piece has a second back yoke portion,
the first back yoke portion and the second back yoke portion form a back yoke portion serving as an outer circumferential portion of the stator core, and
the coil is formed by winding a wire around the tooth portion with the insulator therebetween.

[2] The rotating electric machine stator according to claim 1, wherein
the stator core has a structure in which the yoke piece between the magnetic pole pieces adjacent to each other in the circumferential direction among the plurality of magnetic pole pieces is divided into a plurality of yoke pieces in the circumferential direction, or a structure in which a part between the yoke piece and one of the magnetic pole pieces adjacent thereto is divided.
[3] The rotating electric machine stator according to claim 1 or 2, wherein
the insulator is formed so as to cover both end surfaces such that, of both end surfaces in the axial direction of the magnetic pole piece, partial areas in the circumferential direction on at least one of the radially outer side and the radially inner side of both end surfaces are exposed.
[4] The rotating electric machine stator according to any one of claims 1 to 3, wherein
the insulator is formed so as to cover, of both end surfaces in the axial direction of the yoke piece, partial areas in the circumferential direction on the radially inner side of both end surfaces, and so as to cover a part of an

inner side surface on the radially inner side of the yoke piece.
[5] The rotating electric machine stator according to claim 4, wherein
the yoke piece has a projection or a recess on the inner side surface on the radially inner side, and
the insulator is formed so as to cover the projection or the recess.
[6] The rotating electric machine stator according to claim 4 or 5, wherein
openings which open in the axial direction are formed in both end surfaces in the axial direction of the yoke piece, and
the insulator is formed so as to fill insides of the openings.
[7] The rotating electric machine stator according to any one of claims 1 to 6, wherein
the insulator has a protrusion protruding in the axial direction on one end surface in the axial direction of the yoke piece, and
a jumper wire passed between the tooth portions adjacent to each other in the circumferential direction of

the coil is hooked on the protrusion.
[8] The rotating electric machine stator according to any one of claims 1 to 7, wherein
when the stator core is developed in a straight shape such that the circumferential direction of the first back yoke portions of the magnetic pole pieces and the circumferential direction of the second back yoke portion of the yoke piece are aligned, a center point on the second back yoke portion of the yoke piece is located on the radially outer side with respect to a center point on the first back yoke portion of each magnetic pole piece.
[9] The rotating electric machine stator according to any one of claims 1 to 8, further comprising a molding resin portion covering an entirety of the coil and covering at least parts of the plurality of magnetic pole pieces and the plurality of yoke pieces.
[10] The rotating electric machine stator according to claim 9, further comprising a jumper wire passed between the tooth portions adjacent to each other in the circumferential direction of the coil, wherein
the molding resin portion covers the jumper wire.

[11] A method for manufacturing the rotating electric machine stator according to any one of claims 1 to 10, the method comprising:
a first step of stacking, in the axial direction, a plurality of the sheet materials stamped as the stator core in a straight shape in which the circumferential direction of the first back yoke portions of the magnetic pole pieces and the circumferential direction of the second back yoke portion of the yoke piece are aligned;
a second step of, using at least parts of both end surfaces in the axial direction of the yoke piece as mold reception portions, placing the stator core in the straight shape into a mold and injecting an insulating material into the mold to mold the insulator integrally with the stator core;
a third step of winding the wire around each tooth portion of the stator core in the straight shape with the insulator therebetween, to form the coil; and
a fourth step of bending ends in the circumferential direction of the first back yoke portion of each magnetic pole piece and the second back yoke portion of the yoke piece of the stator core in the straight shape to which the coil has been formed, so as to form the stator core into an annular shape.

[12] The method for manufacturing the rotating electric machine stator, according to claim 11, wherein
in the first step, a receiving portion protruding outward of the stator core is formed on at least either the magnetic pole piece or the yoke piece, and
in the second step, the stator core in the straight shape is placed in the mold, using the receiving portion as the mold reception portion,
the method further comprising a removal step of removing the receiving portion from the stator core, after the second step and before the third step.
[13] The method for manufacturing the rotating electric machine stator, according to claim 11 or 12, further comprising a fifth step of forming the molding resin portion covering an entirety of the coil and covering at least parts of the plurality of magnetic pole pieces and the plurality of the yoke pieces.