Manufacturing method of stator for rotating electric machine and crown tool

Abstract

To simultaneously twist a protruding portion and a slightly twisted protruding portion using a common crown tool without performing pre-forming when the protruding portion has the slightly twisted protruding portion.SOLUTION: In a manufacturing method of simultaneously twisting a large number of protruding portions 34 protruding from a stator core 12 by rotating a crown tool 40, in which a large number of locking grooves 42 are provided, relative to the stator core 12 and causing the crown tool to relatively approach in an axial direction, while some of a large number of protruding portions 34 have slightly twisted protruding portions 34a whose twist angle is small by one slot angle, the crown tool 40 includes a slightly twisted locking groove 42a into which a tip 36a of the slightly twisted protruding portion 34a is inserted, of which groove width in the circumferential direction is larger than that of the other locking grooves 42, and which has a predetermined processed locking surface 44, and the protruding portion 34 is twisted by a first twisting angle, and simultaneously, the slightly twisted protruding portion 34a is twisted by a second twisting angle.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a manufacturing method of a stator for a rotating electric machine and a crown tool used in the manufacturing method, and more particularly to a technique for twisting coil segments that form a stator coil. [Background technology]

[0002] A stator for a rotating electric machine is known, which has: (a) a cylindrical stator core having a large number of slots on its inner periphery that are spaced circumferentially and equiangularly spaced apart and extend along the axis of the cylindrical shape; (b) a large number of coil segments that are approximately U-shaped and are arranged in the stator core with a pair of straight portions of the U-shape housed in different slots among the large number of slots and with a portion of the tip side of the pair of straight portions protruding from the slot in the axial direction of the stator core; and (c) a stator for a rotating electric machine is known, which has a pair of straight portions of the large number of coil segments that protrude from the stator core, the straight portions of the large number of coil segments being twisted around the axis of the stator core and the tip ends of the protruding portions of different coil segments being joined together to form a stator coil. A method for manufacturing a stator for a rotating electric machine has been proposed, which includes the steps of: (d) using a crown tool that is cylindrical and arranged coaxially with the stator core, and has a number of locking grooves that are circumferentially spaced apart from one another and into which the tips of the multiple protruding portions are inserted, and (e) rotating the crown tool relative to the stator core about the axis and moving it relatively close to the stator core in the axial direction, thereby twisting the multiple protruding portions simultaneously about the axis by a predetermined first twist angle. The manufacturing method described in Patent Document 1 is one example.

[0003] In Patent Document 1, some of the numerous protruding portions have a small twist protruding portion that is twisted by a second twist angle that is one slot angle smaller than the first twist angle, with the arrangement interval angle of the slots around the axis being one slot angle. Therefore, a preforming is performed in which the small twist protruding portion is twisted in the opposite direction by one slot angle, and then a common crown tool is used to simultaneously twist the protruding portion and the small twist protruding portion by the first twist angle in the desired twist direction (see Figures 10 to 13). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-110025 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when such a small twisted protruding portion is provided, if a preforming process is performed in advance by twisting the small twisted protruding portion in the opposite direction, there is a problem that the number of processing tools and processing steps increases accordingly, resulting in higher manufacturing costs.

[0006] The present invention has been made against the background of the above circumstances, and its object is to make it possible, when there is a small twist protruding portion with a small twist angle, to simultaneously twist the protruding portion and the small twist protruding portion using a common crown tool without performing preforming. [Means for solving the problem]

[0007] In order to achieve this object, the first invention relates to a stator for a rotating electric machine, comprising: (a) a stator core having a cylindrical shape and including a large number of slots (gaps) on an inner periphery thereof, the slots (gaps) extending along the axis of the cylindrical shape and spaced apart in the circumferential direction at equal angular intervals; and (b) a large number of coil segments having a substantially U-shape and arranged in the stator core with a pair of straight portions of the U-shape housed in different slots among the large number of slots and with a portion of a tip side of the pair of straight portions protruding from the slot in the axial direction of the stator core, (c) a large number of protruding portions of the straight portions of the large number of coil segments protruding from the stator core are twisted around the axis of the stator core and tip ends of the protruding portions of the different coil segments are joined together to form a stator coil; (d) a crown tool having a cylindrical shape and arranged coaxially with the stator core and including a large number of locking grooves circumferentially spaced apart in correspondence with the large number of protruding portions, into which the tip ends of the large number of protruding portions are inserted; and (e) In the manufacturing method of the stator for a rotating electric machine, the method includes a twisting step of twisting the multiple protruding portions simultaneously around the axis by rotating the crown tool relative to the stator core about the axis and moving the crown tool relatively close to the stator core in the axial direction with the tip ends of the protruding portions inserted into the engagement grooves, the multiple protruding portions being twisted about the axis by a predetermined first twist angle, the method further includes the steps of: (f) having a small twist protruding portion in one of the multiple protruding portions, the small twist protruding portion being twisted by a second twist angle that is one slot angle smaller than the first twist angle, where an arrangement interval angle of the slots about the axis is one slot angle; (g) the crown tool is provided with a small twist engagement groove into which the tip end of the small twist protruding portion is inserted and a second groove width that is a groove width in the circumferential direction is larger than the first groove width of the engagement groove; and (h) The small twist engaging groove has a processing engaging surface that is engaged with a tip end of the small twist protruding portion when the crown tool is rotated relative to the stator core by the one slot angle in the twisting process, and (i)In the twisting step, the protruding portion other than the small twist protruding portion is twisted by the first twist angle by engagement with the locking groove, and at the same time, the small twist protruding portion is twisted by the second twist angle by engagement with the processed locking surface of the small twist locking groove. (j) a positioning protrusion is provided at a groove bottom of the small twist engaging groove, which is spaced from the processing engaging surface of the small twist engaging groove by a dimension substantially equal to the width dimension of the tip of the small twist protrusion, and which is engaged with the tip of the small twist protrusion to position the tip between the processing engaging surface, and (k) when the crown tool is rotated relatively to the stator core by the one slot angle in the twisting process, the tip of the small twist protrusion is inserted and positioned between the processing engaging surface of the small twist engaging groove and the positioning protrusion, and twisting is performed on the small twist protrusion with the tip restrained. It is characterized by the above.

[0009] No. 2The invention relates to a stator for a rotating electric machine having: (a) a stator core having a cylindrical shape and having a large number of slots on an inner periphery thereof, the slots extending along the axis of the cylindrical shape being spaced apart in the circumferential direction at equal angular intervals; and (b) a large number of coil segments having a substantially U-shape and arranged in the stator core with a pair of straight portions of the U-shape housed in different slots among the large number of slots and with a portion of a tip side of the pair of straight portions protruding from the slot in the axial direction of the stator core, (c) a stator for a rotating electric machine having a stator coil formed by twisting a large number of protruding portions of the straight portions of the large number of coil segments protruding from the stator core around the axis of the stator core and joining tips of the protruding portions of different coil segments together; and (d) In a crown tool for manufacturing the stator for a rotating electric machine, the crown tool is cylindrically arranged coaxially with the stator core, and has a number of engagement grooves into which the tip portions of the number of protruding portions are inserted, the number of engagement grooves being provided at intervals in the circumferential direction corresponding to the number of protruding portions, and the number of protruding portions is twisted simultaneously about the axis by a predetermined first twist angle by rotating the crown tool relative to the stator core about the axis and moving relatively close to each other in the axial direction with the tip portions of the protruding portions inserted into the number of engagement grooves, the number of protruding portions being twisted simultaneously about the axis by a predetermined first twist angle ... The small twist locking groove has a processing locking surface that is engaged with a tip end of the small twist protrusion when the crown tool is rotated by the one slot angle relative to the stator core; and (h)The small twist engagement groove is characterized in that a positioning protrusion is provided at the bottom of the small twist engagement groove, which is spaced from the processed engagement surface by a distance approximately equal to the width dimension of the tip of the small twist protrusion, and which engages with the tip of the small twist protrusion to position the tip between the processed engagement surface.

[0010] No. 3 The invention is 2 In the crown tool of the invention, the second groove width of the small twist engagement groove is larger than the first groove width of the engagement groove by one slot angle. Effect of the Invention

[0011] According to the manufacturing method of the stator for a rotating electric machine of the first invention, the crown tool for performing the twisting process is provided with a small twisting locking groove into which the tip of the protruding part is inserted, the second groove width of which is larger than the first groove width of the locking groove, and the small twisting locking groove has a predetermined processing locking surface, and in the twisting process, the crown tool is rotated relative to the stator core and is relatively approached in the axial direction, so that the protruding parts other than the small twisting protruding part are twisted by the first twisting angle, and at the same time, the small twisting protruding part is twisted by the second twisting angle. In other words, when there is a small twisting protruding part with a smaller twisting angle than the protruding part, the small twisting protruding part can be twisted at the same time as the protruding part using a common crown tool without performing preforming, and the number of processing tools and processing steps is reduced, thereby suppressing the manufacturing cost. In addition, a positioning protrusion is provided at the bottom of the small twist engagement groove of the crown tool, and in the twisting process, the tip of the small twist protrusion is inserted and restrained between the processing engagement surface and the positioning protrusion, and the twisting process is performed on the small twist protrusion in this state. Therefore, the small twist protrusion, including the shape of its tip, can be appropriately twisted into the desired shape.

[0013] No. 2 The invention of the crown tool is the first Ming It is used in the manufacturing process and is essentially the first Ming and The same effect can be obtained. [Brief description of the drawings]

[0014] [Figure 1] 1 is a perspective view illustrating a schematic configuration of a stator for an electric vehicle rotating electric machine manufactured by the method of the present invention; [Diagram 2]FIG. 2 is a development view illustrating a state in which a single coil segment is disposed in the stator core of the stator in FIG. 1, developed around axis C as viewed from the inner periphery side of the stator core. [Diagram 3] This is a diagram explaining a stator core in which a large number of coil segments are arranged, and multiple protruding portions at the outermost circumference that protrude axially from the stator core, and is an exploded view showing the stator core expanded around axis C as viewed from the outer periphery side. [Figure 4] 4 is a development view showing a state after the multiple protruding portions shown in FIG. 3 have been twisted around an axis C. FIG. [Diagram 5] FIG. 5 is a perspective view illustrating a crown tool used in the twisting process of FIG. 4. [Figure 6] 6 is a diagram illustrating a twisting process in which two types of twisting processes with different twist angles are simultaneously performed using the crown tool in FIG. 5. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A rotating electric machine is a rotating electrical machine, sometimes called a rotating machine, and is a motor generator used as an electric motor or generator, or both, such as a permanent magnet type three-phase AC synchronous motor. The present invention is applied to a stator of an electric vehicle rotating electric machine used as a driving force source for driving an electric vehicle such as an electric car or a hybrid vehicle, but is also applied to a manufacturing technology of a stator for various rotating electric machines, such as a generator of a series type hybrid vehicle, and an electric motor or generator for non-vehicle use. The first twist angle of the protruding part of the coil segment is, for example, 3 slot angles (3 times 1 slot angle), and the second twist angle in this case is 2 slot angles, but these twist angles are appropriately determined under the condition that the second twist angle is smaller than the first twist angle by 1 slot angle.

[0016] The second groove width of the small twist locking groove of the crown tool is, for example, one slot angle larger than the first groove width of the locking groove, but may be larger than the first groove width plus one slot angle. In addition, the small twist protruding portion that is locked in the small twist locking groove and twisted can have a shorter protruding dimension by the smaller twist angle, so the second groove width can be smaller than the first groove width plus one slot angle within a range that does not interfere with the small twist protruding portion. It is desirable to provide a positioning protrusion for positioning the tip of the small twist protruding portion at the groove bottom of the small twist locking groove, but this positioning protrusion can be omitted. In that case, a separate shaping jig may be used to define the twist shape of the small twist protruding portion, or post-processing may be performed to shape it into the desired shape. Even if a positioning protrusion is provided, a shaping jig may be used or post-processing may be performed for shaping as necessary. EXAMPLES

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are appropriately simplified or modified for the purpose of explanation, and the shapes, dimensional ratios, angles, etc. of the various parts are not necessarily drawn accurately.

[0018] Fig. 1 is a perspective view for explaining a schematic configuration of a stator 10 of a rotating electric machine MG to which the present invention is applied. The rotating electric machine MG is a motor generator used as a driving force source for an electric vehicle such as a hybrid vehicle or an electric car, and is a three-phase AC synchronous motor or the like, and includes a cylindrical stator 10 and a rotor (not shown) disposed on the inner periphery of the stator 10 so as to be relatively rotatable about a common center line, that is, an axis C. The stator 10 is a stator for a rotating electric machine.

[0019] The stator 10 includes a cylindrical stator core 12 concentric with the axis C, a stator coil 14, and a power line 16. The stator core 12 is formed by laminating a large number of annular steel plates in an axial direction parallel to the axis C at a right angle to the axis C. A plurality of teeth 20 are provided on the inner peripheral surface of the stator core 12 at equal angular intervals around the axis C in parallel with the axis C. Slots 22, which are groove-shaped gaps, are formed between the teeth 20 adjacent to each other in the circumferential direction around the axis C, and the stator coil 14 wound around the teeth 20 is accommodated in the slots 22. The arrangement interval angle of the slots 22 around the axis C is the same as the arrangement interval angle of the teeth 20, and this angle is expressed as one slot angle θs.

[0020] In this embodiment, the stator coil 14 is a three-phase winding having U, V, and W phases, and each end of the stator coil 14 is electrically connected to a power line 16. An external terminal 18 is attached to the tip of each of the power lines 16 for connection to an inverter or the like (not shown). In this embodiment, the stator coil 14 is a distributed winding wound across a plurality of teeth 20, and is connected in a Y connection.

[0021] The stator coil 14 is composed of coil segments 24 shown in FIG. 2. FIG. 2 shows one coil segment 24 arranged in a slot 22 formed in the stator core 12, and an insulating material 26 such as foamed insulating paper is arranged on the inner peripheral surface of the slot 22 in advance. FIG. 2 is a development view of the stator core 12 seen from the inner peripheral side (axis C side) of the stator core 12. The coil segment 24 is substantially U-shaped, and a pair of parallel straight portions 30 of the U-shape are accommodated in different slots 22 among the many slots 22 in a posture that is substantially parallel to the axis C, and the coil segment 24 is arranged in the stator core 12 so that the U-shaped winding portion 32 and the pair of straight portions 30 protrude from the slot 22 to both sides in the axial direction of the stator core 12 (in a direction parallel to the axis C, the up-down direction in FIG. 2). In the many slots 22 around the axis C, many coil segments 24 are continuously arranged while being shifted in the circumferential direction and the radial direction around the axis C.

[0022] As shown in Fig. 1, a large number of protruding portions 34, which are parts of the straight portions 30 of the many coil segments 24 on the tip side protruding from the slots 22, are twisted around the axis C, which is the circumferential direction of the stator core 12, and the tip portions 36 of the protruding portions 34 are overlapped and joined to other coil segments 24 adjacent in the radial direction. That is, a large number of protruding portions 34 positioned consecutively in the radial direction of the stator core 12 are twisted alternately in opposite directions around the axis C in the radial direction, and the tip portions 36 of a pair of protruding portions 34 adjacent in the radial direction are joined to form a stator coil 14 wound across a plurality of teeth 20. In Fig. 1, the innermost protruding portion 34 is twisted in the clockwise direction as viewed from above in Fig. 1, and the twist direction is alternately reversed toward the outer periphery, and the outermost protruding portion 34 (the eighth from the inner periphery in Fig. 1) is twisted in the counterclockwise direction as viewed from above in Fig. 1. In this embodiment, the coil segments 24 are made of flat wire having a rectangular cross section like a longitudinal conductor plate, with an insulating coating such as enamel provided on the surface, and the insulating coating has been removed from the tips 36 of the protruding portions 34, and the tips 36 are joined together by welding.

[0023] FIG. 3 is a diagram for explaining a number of coil segments 24 arranged on the stator core 12 and a number of protruding parts 34 at the outermost periphery protruding from the stator core 12 in the axial direction, and is a development view showing the stator core 12 developed around the axis C as viewed from the outer periphery side. FIG. 3 shows the state before the protruding parts 34 are twisted, and FIG. 4 shows the state after the protruding parts 34 are twisted. As is clear from these figures, the power line connection protruding parts 34b, which are part of the multiple protruding parts 34, are bent toward the outer periphery side of the stator core 12 in the radial direction (the front side of the paper in FIG. 3 and FIG. 4) prior to the twisting process, so as not to be twisted. As shown in FIG. 1, the power line connection protruding parts 34b are provided at three locations in the entire stator 10. That is, the power line connection protruding parts 34b are provided corresponding to the U phase, V phase, and W phase, and the tip parts 36b are respectively connected to the power lines 16 by welding or the like.

[0024] As is clear from Fig. 4, the three protruding portions 34a adjacent to the three power line connecting protruding portions 34b on the twisting direction side (the right side in Figs. 3 and 4) around the axis C are small twist protruding portions whose twist angle Φ is smaller by one slot angle θs than the other protruding portions 34. That is, if the twist angle Φ of the other protruding portions 34 excluding the small twist protruding portions 34a and the power line connecting protruding portions 34b is a first twist angle Φ1 and the twist angle Φ of the small twist protruding portion 34a is a second twist angle Φ2, then Φ2 = Φ1 - θs, and in this embodiment, the first twist angle Φ1 = 3θs and the second twist angle Φ2 = 2θs. The three small twist protruding portions 34a connect the U1 phase and the U2 phase, the V1 phase and the V2 phase, or the W1 phase and the W2 phase, respectively, and the tip portion 36a of this small twist protruding portion 34a is joined to the tip portion 36 of another radially adjacent coil segment 24, like the other tip portions 36. As is clear from Fig. 3, the protruding dimension of the small twist protruding portion 34a is smaller than the other protruding portions 34 by the amount that the twist angle Φ is smaller, and the length dimension of the straight portion 30 of the coil segment 24 having the small twist protruding portion 34a is shorter than the length dimension of the straight portion 30 of the other coil segments 24.

[0025] Here, when manufacturing the stator 10 shown in FIG. 1, a twisting process is required to twist the protruding portion 34 and the small twisted protruding portion 34a having different twist angles Φ as shown in FIG. 3 and FIG. 4. FIG. 5 is a perspective view of a crown tool 40 for simultaneously twisting the protruding portion 34 and the small twisted protruding portion 34a, specifically showing the portion for twisting the four protruding portions 34 and one small twisted protruding portion 34a shown in FIG. 3 and FIG. 4. The crown tool 40 has a cylindrical shape centered on a center line O, and is arranged in a position where the center line O coincides with the axis C, that is, in a position where the center line O is coaxial with the stator core 12. In addition, at the end portion facing the stator core 12, that is, the lower end portion in FIG. 5, a number of locking grooves 42, 42a into which the tip portions 36, 36a of the many protruding portions 34, 34a are inserted are provided at intervals in the circumferential direction corresponding to the protruding portions 34, 34a. That is, the diameter of the crown tool 40 is approximately the same as the diameter of the outermost portion of the slot 22 in which the protruding portions 34, 34a are located, and the engagement grooves 42, 42a are spaced apart at the same intervals as the protruding portions 34, 34a, i.e., at intervals of one slot angle θs around the axis of the cylindrical shape.

[0026] The crown tool 40 is arranged coaxially with the stator core 12, and is rotated in the circumferential direction about the axis C by a predetermined twisting angle ωt as shown in Fig. 6, and is also rotated counterclockwise in a spiral manner so as to approach the stator core 12 in the Z-axis direction by a predetermined twisting feed amount Zt, thereby binding the tip ends 36, 36a of the protruding parts 34, 34a with the locking grooves 42, 42a and performing a twisting process. The twisting angle ωt is equal to the first twisting angle Φ1 (=3θs), and the protruding part 34 locked in the locking groove 42 is twisted by the first twisting angle Φ1. 6A and 6B are diagrams for explaining the twisting process for twisting the protruding parts 34, 34a, and (a) shows an initial state of the twisting process in which the crown tool 40 is brought close to the stator core 12 until the tip ends 36, 36a of the protruding parts 34, 34a are inserted into the engagement grooves 42, 42a of the crown tool 40 before the twisting process is performed. In this embodiment, the tip end 36a of the small twist protruding part 34a is also inserted into the small twist engagement groove 42a, but in the initial state of the twisting process in (a), the tip end 36a of the small twist protruding part 34a does not have to be inserted into the small twist engagement groove 42a.

[0027] 6(b) shows a state where the crown tool 40 is rotated around the axis C by a twisting angle ωt from the initial state of (a) and is moved toward the stator core 12 by a twisting feed amount Zt, so that the protruding portion 34 engaged in the locking groove 42 is twisted by a first twisting angle Φ1 and the small twisted protruding portion 34a engaged in the locking groove 42a is twisted by a second twisting angle Φ2. In this twisting process, a cuff support 50 is disposed between the many protruding portions 34, 34a around the axis C, and controls the twisted shape of the protruding portions 34, 34a protruding from the stator core 12. These cuff supports 50 are removed after the twisting of the protruding portions 34, 34a is completed, but may be left on the stator 10 as they are.

[0028] Here, the first groove width W1, which is the circumferential groove width of the locking groove 42 into which the tip 36 of the protruding portion 34 is inserted, is approximately the same as the width dimension of the tip 36 of the protruding portion 34, and the twisting process is performed so that the protruding portion 34 has the target shape shown in Fig. 6(b) while the tip 36 is held in a position approximately parallel to the axis C. That is, the twist feed amount Zt and the axial feed rate are determined so that the twisting process is performed on the protruding portion 34 while maintaining the tip 36 of the protruding portion 34 inserted and locked in the locking groove 42. On the other hand, the locking groove 42a into which the tip 36a of the small twist protruding portion 34a is inserted is a small twist locking groove that twists the small twist protruding portion 34a by the second twist angle Φ2 (=2θs) by approaching the small twist protruding portion 34a by the twist feed amount Zt while rotating the crown tool 40 by the twist rotation angle ωt. The second groove width W2, which is the circumferential groove width of this small twist locking groove 42a, is made larger by one slot angle θs in the opposite direction to the twist direction (leftward in FIG. 6) than the first groove width W1 of the other locking grooves 42, and while the crown tool 40 rotates by one slot angle θs from the initial state of the twist processing in FIG. 6(a), the small twist locking groove 42a is made to rotate idly with respect to the small twist protruding portion 34a, and the small twist protruding portion 34a is maintained in the same vertical state as in FIG. 6(a). Then, when the crown tool 40 is rotated by one slot angle θs, the processing locking surface 44, which is one end face in the circumferential direction of the small twist locking groove 42a, i.e., the rear end face in the twist rotation direction, is engaged with the tip portion 36a of the small twist protruding portion 34a, and thereafter, the small twist protruding portion 34a is also twisted to the rightward in FIG. 6(b) as the crown tool 40 rotates.

[0029] At the bottom of the small twist locking groove 42a, when the crown tool 40 is rotated by one slot angle θs from the initial state of the twisting process to engage the tip end 36a of the small twisting protrusion 34a with the processing locking surface 44, a positioning protrusion 46 is provided which is engaged with the tip end 36a of the small twisting protrusion 34a to position the tip end 36a between the processing locking surface 44. The dimension between the processing locking surface 44 and the positioning protrusion 46 is approximately the same as the width dimension of the tip end 36a of the small twisting protrusion 34a, and thus, the small twisting protrusion 34a is also twisted to have the target shape shown in Fig. 6(b) in a state in which the tip end 36a is constrained to be approximately parallel to the axis C, similar to the protrusion 34. That is, by rotating the crown tool 40 by one slot angle θs from the initial state of twist processing shown in FIG. 6(a), the small twist protrusion 34a is engaged with the processing engagement surface 44, and the tip 36a is inserted and restrained between the processing engagement surface 44 and the positioning protrusion 46. In this state, the crown tool 40 is rotated by two slot angles 2θs and brought close to the stator core 12, whereby the small twist protrusion 34a is twisted by a second twist angle Φ2 (=2θs) to obtain the target shape shown in FIG. 6(b). The twist feed amount Zt and the axial feed rate are determined so that the tip 36 of the protruding portion 34 is kept engaged with the engagement groove 42, and the tip 36a of the small twist protruding portion 34a is inserted between the machining engagement surface 44 of the small twist engagement groove 42a and the positioning protrusion 46, while the twist processing is performed on the small twist protruding portion 34a. If necessary, the rotation speed of the crown tool 40 about the axis C and the axial feed rate may be changed.

[0030] According to the manufacturing method of the stator 10 of this embodiment, in addition to the engagement groove 42 of the first groove width W1 into which the tip portion 36 of the protruding portion 34 is inserted, the crown tool 40 used for twisting is provided with a small twist engagement groove 42a into which the tip portion 36a of the small twist protruding portion 34a is inserted and which has a second groove width W2 larger than the first groove width W1 and is equipped with a predetermined processing engagement surface 44. During the twisting process, the crown tool 40 is rotated relative to the stator core 12 and brought relatively close to the axial direction, so that the protruding portion 34 other than the small twist protruding portion 34a is twisted by the first twist angle Φ1, and at the same time, the small twist protruding portion 34a is twisted by the second twist angle Φ2. In other words, when there is a small twist protruding portion 34a having a smaller twist angle Φ than the protruding portion 34, the small twist protruding portion 34a can be twisted simultaneously with the protruding portion 34 using a common crown tool 40 without performing preforming, thereby reducing the number of processing tools and processing steps and suppressing manufacturing costs.

[0031] In addition, a positioning protrusion 46 is provided at the bottom of the small twist locking groove 42a of the crown tool 40, and in the twisting process, the tip 36a of the small twist protrusion 34a is inserted and restrained between the processing locking surface 44 and the positioning protrusion 46, and the small twist protrusion 34a is twisted in this state. Therefore, the small twist protrusion 34a, including the shape of the tip 36a, can be appropriately twisted into the desired shape.

[0032] In addition, as described in Patent Document 1, when preforming is performed by twisting the small twist protruding portion 34a in the opposite direction by one slot angle θs, and then twisting the protruding portion 34 and the small twist protruding portion 34a simultaneously by the first twist angle Φ1 in the desired twist direction using a common crown tool, the small twist protruding portion 34a slides back and forth in the engagement groove of the crown tool, which may promote wear of the crown tool and increase the frequency of replacement. In contrast, in this embodiment, there is almost no sliding between the small twist engagement groove 42a of the crown tool 40 and the small twist protruding portion 34a, so the durability of the crown tool 40 is improved, and in this respect, manufacturing costs are also suppressed. In addition, in this embodiment, it is sufficient to simply twist the small twist protruding portion 34a by the second twist angle Φ2, so that the occurrence of wrinkles and the like in the small twist protruding portion 34a is suppressed, improving quality, and the length dimension of the small twist protruding portion 34a can be shortened, which reduces the cost by reducing the amount of copper used and improves fuel efficiency by improving losses.

[0033] Although the embodiment of the present invention has been described in detail above with reference to the drawings, this is merely one embodiment, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0034] 10: stator (stator for rotating electric machine) 12: stator core 14: stator coil 22: slot 24: coil segment 30: straight section 34: protruding portion 34a: small twisted protruding portion 36, 36a: tip portion 40: crown tool 42: engagement groove 42a: small twist engagement groove 44: machined engagement surface 46: positioning protrusion MG: rotating electric machine C: axis θs: 1st slot angle Φ1: 1st twist angle Φ2: 2nd twist angle W1: 1st groove width W2: 2nd groove width

Claims

1. a stator core having a cylindrical shape and an inner periphery on which a number of slots extending along an axis of the cylindrical shape are provided at equal angular intervals and spaced apart in a circumferential direction; a number of coil segments each having a substantially U-shape, a pair of straight portions of the U-shape being accommodated in different slots among the number of slots, and a portion of a tip side of the pair of straight portions protruding from the slot in the axial direction of the stator core, the coil segments being disposed in the stator core; a plurality of protruding portions of the linear portions of the plurality of coil segments protruding from the stator core are twisted around an axis of the stator core, and tip ends of the protruding portions of different coil segments are joined together to form a stator coil, a crown tool having a cylindrical shape and arranged coaxially with the stator core, and having a number of engagement grooves spaced apart in the circumferential direction so as to correspond to the number of protruding portions, into which the tip ends of the number of protruding portions are inserted, a twisting step of twisting the multiple protruding portions simultaneously around the axis by a predetermined first twist angle by rotating the crown tool relative to the stator core about the axis and moving the crown tool relatively close to the stator core in the axial direction while the tip ends of the protruding portions are inserted into the locking grooves, a small twisted protruding portion is provided in a part of the multiple protruding portions and is twisted by a second twist angle that is one slot angle smaller than the first twist angle, where an arrangement interval angle of the slots around the axis is one slot angle; The crown tool includes a small twist locking groove into which a tip end of the small twist protruding portion is inserted and a second groove width, which is a groove width in a circumferential direction, is larger than the first groove width of the locking groove, the small twist engaging groove has a processing engaging surface that is engaged with a tip end of the small twist protruding portion when the crown tool is rotated relative to the stator core by the one slot angle in the twisting process, In the twisting step, the protruding portion other than the small twist protruding portion is twisted by the first twist angle by engagement with the locking groove, and at the same time, the small twist protruding portion is twisted by the second twist angle by engagement with the processed locking surface of the small twist locking groove, a positioning protrusion is provided at a groove bottom of the small twist engagement groove, the positioning protrusion being engaged with the tip end of the small twist projection and positioning the tip end between the small twist engagement groove and the processed engagement surface, the positioning protrusion being provided at a groove bottom of the small twist engagement groove, the positioning protrusion being engaged with the tip end of the small twist projection and positioning the tip end between the small twist engagement groove and the processed engagement surface, At the time when the crown tool is rotated by one slot angle relative to the stator core in the twisting process, the tip end of the small twist protrusion is inserted between the processing engagement surface of the small twist engagement groove and the positioning protrusion and positioned, and the small twist protrusion is twisted in a state where the tip end is restrained. A method for manufacturing a stator for a rotating electric machine comprising the steps of:

2. a stator core having a cylindrical shape and an inner periphery on which a number of slots extending along an axis of the cylindrical shape are provided at equal angular intervals and spaced apart in a circumferential direction; a number of coil segments each having a substantially U-shape, a pair of straight portions of the U-shape being accommodated in different slots among the number of slots, and a portion of a tip side of the pair of straight portions protruding from the slot in the axial direction of the stator core, the coil segments being disposed in the stator core; a plurality of protruding portions of the linear portions of the plurality of coil segments protruding from the stator core are twisted around an axis of the stator core, and tip ends of the protruding portions of different coil segments are joined together to form a stator coil, a crown tool having a cylindrical shape and arranged coaxially with the stator core, and having a number of locking grooves spaced apart in the circumferential direction corresponding to the number of protruding portions, into which tip portions of the number of protruding portions are respectively inserted, the crown tool being rotated relative to the stator core about the axis and moved relatively close to the stator core in the axial direction with the tip portions of the protruding portions inserted into the number of locking grooves, thereby twisting the number of protruding portions simultaneously about the axis by a predetermined first twist angle, a small twisted protruding portion is provided in a part of the multiple protruding portions and is twisted by a second twist angle that is one slot angle smaller than the first twist angle, where an arrangement interval angle of the slots around the axis is one slot angle; The crown tool includes a small twist locking groove into which a tip end of the small twist protruding portion is inserted and a second groove width, which is a groove width in a circumferential direction, is larger than the first groove width of the locking groove, the small twist locking groove has a processing locking surface that is engaged with a tip end of the small twist protrusion when the crown tool is rotated by the one slot angle relative to the stator core, A groove bottom of the small twist engaging groove, which is spaced from the processing engaging surface of the small twist engaging groove by a dimension substantially equal to the width dimension of the tip end of the small twist protruding portion, is provided with a positioning protrusion that is engaged with the tip end of the small twist protruding portion and positions the tip end between the processing engaging surface. A crown tool characterized by:

3. The second groove width of the small torsion locking groove is greater than the first groove width of the locking groove by one slot angle.

3. The crown tool according to claim 2.

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