Method for manufacturing stator for rotary electric machine

Abstract

Disclosed is a method for manufacturing a stator for a rotary electric machine, comprising: a preparation step for preparing a workpiece in which a plurality of coil pieces forming a stator coil are attached to a stator core, and joining the tip ends of one coil piece and the other coil piece to each other on one axial end side of the workpiece; an impregnation step in which, after the preparation step, the workpiece is impregnated in the groove of the liquid resin material in such a manner that an impregnation target site including a joining site between the tip portions thereof is impregnated; and a rotation step in which, after the impregnation step, the workpiece is rotated at a rising position of the workpiece at which the portion to be impregnated is separated from the tank. The rotation step includes rotating the workpiece about a workpiece center axis corresponding to the stator center axis in a posture in which the portion to be impregnated faces the workpiece in a direction intersecting the vertical direction.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a stator for a rotating electric machine. Background Art

[0002] A method for manufacturing a stator for a rotating electric machine is known, wherein a workpiece for a rotating electric machine is prepared in which a plurality of coil sheets forming a stator coil are mounted on a stator core, the top ends of the plurality of coil sheets are joined to each other at one axial end of the workpiece, a portion to be impregnated including the joining portion (conductor exposed portion) is impregnated with a liquid resin material, and then the liquid resin material is solidified, thereby covering the joining portion with an insulating coating layer of the resin material.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-136787 Summary of the invention

[0006] Problems to be solved by the present invention

[0007] However, in the manufacturing method of forming the insulating coating layer of such a resin material, it is difficult to effectively reduce the dripping of liquid (the dripping of the liquid resin material) after lifting the workpiece immersed in the tank of the liquid resin material.

[0008] Therefore, in one aspect, the present disclosure is directed to effectively reducing liquid dripping after a workpiece is lifted from a tank.

[0009] Technical means of solving problems

[0010] In one aspect, the present disclosure provides a method for manufacturing a stator for a rotating electrical machine, wherein:

[0011] include:

[0012] A preparation step of preparing a workpiece for mounting a plurality of coil pieces forming a stator coil on a stator core, and joining the respective top ends of one coil piece and another coil piece to each other at one axial end side of the workpiece;

[0013] an immersion step of immersing the workpiece in a tank of a liquid resin material after the preparation step so that the impregnation target area including the joint area between the tip portions is immersed; and

[0014] a rotating step of rotating the workpiece after the immersion step at a raised position of the workpiece where the impregnation target portion is separated from the tank;

[0015] The rotating step includes rotating the workpiece around a workpiece central axis corresponding to a stator central axis in a posture of the workpiece in which the impregnation target portion faces a direction intersecting a vertical direction.

[0016] Effects of the Invention

[0017] In one aspect, according to the present disclosure, liquid dripping after a workpiece is lifted from a tank can be effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic flowchart showing an example of a method for manufacturing a stator for a rotating electrical machine.

[0019] Figure 2 The figure schematically shows the whole of a workpiece for forming a stator for a rotating electrical machine.

[0020] Figure 3 This is a cross-sectional view along the axial direction of the workpiece in a state where the coil pieces are assembled to the stator core.

[0021] Figure 4 This is a front view of a coil sheet.

[0022] Figure 5 This is a schematic cross-sectional view of a coil sheet.

[0023] Figure 6 is an illustration of the joint, and Figure 2 It corresponds to the enlarged view of the Q1 portion.

[0024] Figure 7 This is a diagram schematically showing a workpiece before being immersed in a tank of a liquid resin material, as viewed from the side.

[0025] Figure 8 This is a diagram schematically showing a workpiece immersed in a tank of a liquid resin material when viewed from the side.

[0026] Fig. 9 This is a diagram schematically showing the state of the workpiece in the rotating step in the immersed state when viewed from the side.

[0027] Fig. 9A yes Fig. 9 An enlarged view of the Q9 section.

[0028] Fig. 9B is along Fig. 9A The cross-sectional view taken along line 9A-9A schematically shows the state immediately after immersion (the state before the start of the rotation step in the immersed state).

[0029] Fig. 9C is along Fig. 9AThe cross-sectional view taken along line 9A-9A schematically shows the state after the rotation step in the immersed state is performed.

[0030] Fig.10 This is a diagram schematically showing the state of the workpiece after the lifting step to the vicinity of the liquid surface is completed when viewed from the side.

[0031] Fig.11 This is a diagram schematically showing a workpiece in a liquid removal rotation step when viewed from the side.

[0032] Fig.12 This is an explanatory diagram of the effect of the liquid removal rotation process.

[0033] Fig. 12A It is an explanatory diagram of a preferred rotation direction in the liquid removal rotation step.

[0034] Fig.13 This is a diagram schematically showing a state of the workpiece further lifted upward from the position in the liquid removal rotation step when viewed from the side.

[0035] Fig.14 This is a diagram schematically showing a state of a workpiece in an obliquely downward posture when viewed from the side.

[0036] Fig.15 This is a diagram schematically showing a state of a workpiece in an obliquely downward posture subjected to a reattachment rotation step when viewed from the side.

[0037] Fig.16A This is an explanatory diagram (part 1) of the effect of the reattachment rotation step.

[0038] Fig. 16B This is an explanatory diagram (part 2) of the effect of the reattachment rotation process.

[0039] Fig. 16C This is an explanatory diagram (part 3) of the effect of the reattachment rotation process.

[0040] Fig.17 This is a diagram schematically showing a state of a workpiece in a downwardly inclined posture with a relatively large inclination angle when viewed from the side.

[0041] Fig.18 This is a diagram schematically showing a state of a workpiece in an obliquely upward posture when viewed from the side.

[0042] Fig.18A This is an explanatory diagram (part 1) of a preferred range of the angle α of a workpiece in an oblique upward posture.

[0043] Fig.18B This is an explanatory diagram (part 2) of a preferred range of the angle α of a workpiece in an oblique upward posture.

[0044] Fig.19This is a diagram schematically showing a workpiece in an upward posture when viewed from the side.

[0045] Fig. 20 This is a diagram schematically showing a workpiece in a state where a top surface resin curing process is being performed, when viewed from the side.

[0046] Fig.21 This is a diagram schematically showing a workpiece in a state where a curing process of the inner diameter side resin is being performed, when viewed from the side.

[0047] Fig. 22 This is a diagram schematically showing the state of the workpiece before the second insulation coating step when viewed from the side.

[0048] Fig.23 This is a diagram schematically showing the state of the workpiece in the heating process when viewed from the side.

[0049] Fig.24 This is a diagram schematically showing an example of a cooling structure.

[0050] Fig.25 This is a schematic flowchart showing another example of a method for manufacturing a stator for a rotating electrical machine.

[0051] Fig.26 It is an explanatory diagram of the adhesion of the liquid resin material to the stator core. DETAILED DESCRIPTION

[0052] Hereinafter, each embodiment will be described in detail with reference to the drawings. It should be noted that the dimensional ratios in the drawings are merely examples and are not limited thereto, and that shapes and the like in the drawings may be partially exaggerated for the sake of convenience of description.

[0053] The method for manufacturing a stator for a rotating electric machine described below can be applied to any stator for a rotating electric machine as long as the coil end has a joint portion of a coil sheet. As a preferred application example, a method for manufacturing a stator for a rotating electric machine that can function as a power source for generating propulsion force for a vehicle is described below.

[0054] Figure 1 1 is a schematic flow chart showing an example of a method for manufacturing a stator for a rotating electrical machine. Figure 1 This is a flowchart showing a schematic flow, and further additional steps may be included at any stage. Figures 2 to 6 It is an explanatory diagram of a workpiece W. Figure 2 1 is a diagram schematically showing the entire workpiece W having a stator core 112 and a stator coil 114 for forming a stator 10 for a rotating electrical machine. Figure 3 It is a cross-sectional view along the axial direction of the workpiece W in a state where the coil piece 52 is assembled to the stator core 112 . Figure 4It is a front view of one coil piece 52 among the plurality of coil pieces 52 . Figure 5 It is a schematic cross-sectional view of the coil piece 52 . Figure 6 is an explanatory diagram of the joint portion 400, and Figure 2 It corresponds to the enlarged view of the Q1 portion. Figures 7 to 18 is an illustration of the present manufacturing method, Figures 7 to 9 , Fig.10 , Fig.11 , Figures 13 to 15 , Figures 17 to 22 The diagram schematically shows the state of the workpiece W in each process when viewed from the side. 9A to 9C This is a diagram for explaining the effect of the rotation step in the immersed state. Fig.12 It is to explain the use Fig.11 This is a diagram illustrating the function of the liquid removal rotation process in the Q11 section. Fig. 12A It is an explanatory diagram of a preferred rotation direction in the liquid removal rotation step, and schematically shows a part of the coil end portion 114A when viewed from the side. FIG. 16A to FIG. 16C This is a diagram for explaining the effect of the rotation process.

[0055] exist Figure 2 The Z direction is shown in FIG. The Z direction corresponds to the up-down direction, and the Z1 side and the Z2 side correspond to the upper side and the lower side, respectively. Figure 3 The Y direction is shown in FIG. The Y direction corresponds to the radial direction, the Y1 side corresponds to the radial outer side, and the Y2 side indicates the radial inner side (the side closer to the central axis I of the stator core 112).

[0056] In the following description, unless otherwise specified, the axial direction refers to the direction in which the central axis I (= the central axis of the workpiece W) of the stator core 112 extends, and the radial direction refers to the radial direction centered on the central axis I. Therefore, the radially outer side refers to the side away from the central axis I, and the radially inner side refers to the side close to the central axis I. In addition, the axially outer side refers to the side away from the axial center of the stator core 112, and the axially inner side refers to the side close to the axial center of the stator core 112. In addition, the circumferential direction corresponds to the rotation direction around the central axis I.

[0057] The manufacturing method first includes a preparation step (step S10) before the insulation coating step. In the present embodiment, the preparation step (step S10) includes an assembly forming step (step S200) and a joining step (step S202). However, in a modified example, a workpiece on which the assembly forming step (step S200) has been completed can be used (prepared), or a workpiece on which the assembly forming step (step S200) and the joining step (step S202) have been completed can be used (prepared).

[0058] The assembly forming step (step S200 ) includes mounting a plurality of coil pieces 52 for forming the stator coil 114 on the stator core 112 to form an assembly (hereinafter also referred to as a “workpiece W”).

[0059] Here, the stator coil 114 includes a U-phase coil, a V-phase coil, and a W-phase coil (hereinafter referred to as a "phase coil" when U, V, and W are not distinguished). The base end of each phase coil is connected to an input terminal (not shown), and the end of each phase coil is connected to the end of the other phase coil to form a neutral point. That is, the stator coil 114 is star-connected. However, the connection method of the stator coil 114 can also be appropriately changed according to the required motor characteristics, for example, the stator coil 114 can also be connected in a delta connection instead of a star connection.

[0060] Each phase coil of the stator coil 114 can be formed by combining a plurality of coil pieces 52. The coil piece 52 is a segmented coil (segmented conductor) in which the phase coil is divided into units that are easy to assemble (for example, units that can be inserted into two slots 23). Figure 5 As shown, the coil sheet 52 is formed by covering a linear conductor (flat wire) 120 having a substantially rectangular cross section with an insulating film 130. Here, as an example, the linear conductor 120 is formed of copper. However, in a modified example, the linear conductor 120 may also be formed of other conductive materials such as iron. In addition, the cross-sectional shape of the linear conductor 120 may also be a shape other than a rectangle.

[0061] exist Figure 4 In the example shown, one coil sheet 52 may be formed into a substantially U-shape having a pair of linear slot accommodating portions 50 and a transition portion 54 connecting the pair of slot accommodating portions 50. Figure 4 The transition portion 54 can be made by Figure 4 The state shown is formed along the circumferential direction. Figure 4 The end of the transition portion 54 (on the upper side) is set with a joint portion 40 that is joined to the joint portion 40 of the transition portion 54 of the other coil piece 52. In addition, the joint portion 40 is a portion where the insulating film 130 is removed (i.e., a portion where the conductor portion of the linear conductor 120 is exposed).

[0062] When the coil sheet 52 is assembled to the stator core 112, the pair of slot accommodating portions 50 are respectively inserted into the slots 23 between the teeth 22 (see Figure 3 ). In this case, the coil sheet 52 can be assembled in the axial direction, for example.

[0063] In one groove 23, a plurality of Figure 4The slot receiving portion 50 of the coil sheet 52 shown in the figure. Therefore, a plurality of transition portions 54 extending in the circumferential direction are arranged radially at both ends of the axial direction of the stator core 112. In addition, the transition portion 54 (and the connecting portion 40 as a part thereof) forms a portion protruding axially outward from the axial end face 1120 of the stator core 112, namely, the coil end 114A (see Figure 3 ). In addition, the coil sheet 52 may be wound on the stator core 112 in an overlapping winding manner, for example. Figure 4 In the example shown, the lower transition portion 54 may have an offset portion 521B that is offset in a direction that is separated from each other by one layer in the radial direction. The upper transition portion 54 may also have a similar offset portion 521A (see Figure 3 ).

[0064] In addition, Figure 2 to Figure 5 4 shows a stator core 112 and a stator coil 114 of a specific structure, but the structure of the stator core 112 and the stator coil 114 is arbitrary as long as the stator coil 114 has a coupling portion 40. In addition, the winding method of the stator coil 114 is also arbitrary, and may be a winding method other than the above-mentioned overlapping winding form such as a wave winding form.

[0065] The joining process (step S202) includes joining the top end portions, i.e., the joining portions 40, of one coil sheet 52 and another coil sheet 52 at one axial end of the workpiece W. The joining portions 40 may overlap with each other and be joined on the sides facing each other. The joining method of the joining portions 40 is arbitrary, but welding may be used, for example. In this case, welding may be achieved by any method such as laser welding or TIG welding. Figure 6 Schematically shows a joint portion 400 including a welded portion 401 (joined portion) formed at two joining portions 40 overlapped in the radial direction.

[0066] For example, when a plurality of coil pieces 52 are installed in four or more slots 23 of the stator core 112 in a radially overlapping manner, the joining process can join a plurality of groups radially by treating two radially adjacent coupling portions 40 (top ends) as a group.

[0067] In addition, the joining range of the joining parts 40, the posture of the joining parts 40 when joined (the posture when overlapping), etc. are arbitrary. Figure 6 In the embodiment, the coupling parts 40 stand upright in the up-down direction and overlap in the radial direction, but can overlap in an X-shaped cross when viewed in the radial direction, or can overlap in the radial direction only when the coupling parts 40 are in an inclined direction. In addition, the coupling parts 40 can overlap in the axial direction when extending in the radial direction.

[0068] In the joining process, not only the coil pieces 52 can be joined to each other, but also the coil pieces 52 can be joined to bus bars and terminal blocks (output bus bars for connecting to an inverter not shown). Figure 2 Schematically showing a neutral bus bar 59 as an example of a bus bar. The neutral bus bar 59 is a bus bar that forms the above-mentioned neutral point.

[0069] In this embodiment, as an example, the joint portion 400 is provided only on one axial side of the stator core 112. Hereinafter, for the sake of distinction, the side having the joint portion 400 on both axial sides of the stator core 112 (or both axial sides of the workpiece W) is also referred to as the lead side. In addition, in a modified example, the joint portion 400 may also be provided on both axial sides of the stator core 112.

[0070] After the preparation step (step S10), the manufacturing method includes a step of placing the workpiece W at the starting position (workpiece loading position) for the insulation coating step (step S204). At this time, the workpiece W can be placed in a posture with the lead side facing upward (i.e., a posture with the joint 400 facing upward). Hereinafter, such a posture with the lead side facing upward is also referred to as "upward posture of the workpiece W".

[0071] Next, as the first step of the insulation coating step, the present manufacturing method includes an upside-down inversion step (step S206) of inverting the posture of the workpiece W. That is, the workpiece W is inverted upside down to a posture with the lead side at the bottom (that is, a posture with the joint 400 at the bottom). Hereinafter, such a posture with the lead side at the bottom is also referred to as "downward posture of the workpiece W". The upside-down inversion of the posture of the workpiece W can also be achieved by a manufacturing device. In addition, the manufacturing device can be, for example, a multi-joint robot having a hand that grasps the workpiece W, and the workpiece gripping portion 1000 that is a part of the manufacturing device is described later. Figure 7 As shown in etc.

[0072] Next, the present manufacturing method includes a dipping step of dipping the workpiece W into the tank 600 of the liquid resin material M0 (step S208 ). Figure 7 6 is a diagram schematically showing the workpiece W before being immersed in the groove 600 of the liquid resin material M0 when viewed from the side. Figure 8 This is a diagram schematically showing a workpiece W immersed in a groove 600 of a liquid resin material M0 when viewed from the side. In the present manufacturing method, as a preferred example, the liquid resin material M0 is a resin material having the characteristics of being cured by heating and being cured by a polymerization reaction when irradiated with ultraviolet rays. In addition, the viscosity of the liquid resin material M0 is relatively high, for example, having a viscosity greater than 10 Pa·s, preferably having a viscosity of more than 20 Pa·s. In addition, the groove 600 can have a circular ring-shaped shape corresponding to the circular ring-shaped impregnation object portion when viewed from above.

[0073] The impregnation process is performed in a state where the workpiece W is maintained in a downward posture, in which the impregnation target portion of the axial end (the end on the lower side in the downward posture) of the workpiece W is immersed in the liquid resin material M0 (that is, in a manner located below the liquid surface 601 of the liquid resin material M0). The impregnation target portion of the workpiece W is set at the position of the plurality of coil pieces 52 in the workpiece W. Specifically, the impregnation target portion of the workpiece W is the axial end (the end on the lead side) of the plurality of coil pieces 52, including the joint 400. More specifically, the impregnation target portion of the workpiece W includes the exposed portion (including the portion of the joint 400) of the conductor (the conductor portion of the linear conductor) in each coil piece 52 of the workpiece W. When observed from the axial direction, the impregnation target portion is annular in shape around the central axis I, including a portion of the coil end 114A (a portion on the axial end side).

[0074] In addition, in the present manufacturing method, the impregnation target portion is set to include the neutral bus bar 59. In this case, by wrapping the neutral bus bar 59 with the liquid resin material M0, the electrical insulation of the neutral bus bar 59 can be ensured. That is, the neutral bus bar 59 does not need to be in a form in which an insulating material such as a resin material is insulated and covered in advance by insert molding, etc., and can be in the form of a metal plate (a form in which the conductive material is exposed as a whole). Thus, the electrical insulation of the neutral bus bar 59 can be effectively ensured.

[0075] In addition, in the present manufacturing method, as described later, the immersion process is performed twice on one workpiece W. In this case, the impregnation target parts of the workpiece W in each immersion process may be completely the same or partially different. However, in a modified example, the number of times the immersion process is performed on one workpiece W may be once or three or more times.

[0076] In the dipping step, the workpiece W can be held in a dipping state in a downward posture for a certain period of time by the workpiece holding unit 1000 of the manufacturing apparatus.

[0077] In the present manufacturing method, the immersion step includes a rotating step of rotating the immersed workpiece W (in a downward posture) about the central axis I (see Fig. 9 Hereinafter, in order to distinguish it from other rotation steps described later, the rotation step performed in such an immersion step is also referred to as a "rotation step in the immersed state".

[0078] Figures 9 to 9C This is an illustration of the rotation process in the immersed state. Fig. 9 is a diagram schematically showing a workpiece W in a rotating process in an immersed state when viewed from the side. Fig. 9A yes Fig. 9 An enlarged view of the Q9 section. Fig. 9B and Fig. 9C is along Fig. 9A A cross-sectional view taken along line 9A-9A, Fig. 9B Schematically shows the state immediately after immersion (the state before the start of the rotation process in the immersed state). Fig. 9C Schematically shows the state after the rotation process in the immersed state is performed. Fig. 9B and Fig. 9C In FIG. 1 , the L direction corresponds to the circumferential direction of the workpiece W, and L1 and L2 indicate opposite sides (one side and the other side in the circumferential direction) to each other.

[0079] The rotation process in the impregnated state is performed in order to more effectively wrap the neutral bus bar 59 with the liquid resin material M0. In the present embodiment, the neutral bus bar 59 extends circumferentially in a direction perpendicular to the upper surface 591 and parallel to the central axis I, and is electrically insulated by being covered with the liquid resin material M0 as described above. In addition, the neutral bus bar 59 may be arranged at any position relative to the coil end 114A, for example, it may be joined to the stator coil 114 in a manner extending axially outward compared to the coil end 114A. However, in the present embodiment, as Fig. 9 As schematically shown in FIG. 1 and FIG. 2 , the neutral bus bar 59 is connected to the stator coil 114 with the upper surface 591 (hereinafter referred to as “upper surface 591”) in a downward posture, and is located in the Z direction between the axial end surface 1140 of the stator coil 114 and the axial end surface 1120 of the stator core 112. In this case, the axial volume of the stator 10 for the rotating electrical machine can be reduced. In addition, the axial end surface 1140 of the stator coil 114 corresponds to the axial end surface of the coil end 114A.

[0080] However, when the neutral bus bar 59 is wrapped with the liquid resin material M0 in this way, efficiently guiding the liquid resin material M0 onto the upper surface 591 of the neutral bus bar 59 is useful in achieving a reduction in CT (Cycle Time).

[0081] Here, as shown in the present embodiment, when the upper surface 591 of the neutral bus bar 59 is located on the Z1 side (upper side in the downward posture) of the axial end surface 1140 of the stator coil 114, the boundary of the Z1 side of the impregnation target portion tends to be determined by the upper surface 591 of the neutral bus bar 59. For example, the boundary of the Z1 side of the impregnation target portion is set to be slightly closer to the Z1 side than the upper surface 591 of the neutral bus bar 59. In such a setting method of the impregnation target portion, the upper surface 591 of the neutral bus bar 59 is only located slightly below the liquid level 601 of the liquid resin material M0 in the impregnation state, and it is difficult to make the liquid resin material M0 quickly spread over the upper surface 591.

[0082] However, in the present manufacturing method, by performing the rotating step in the immersed state, the liquid resin material M0 can be quickly spread over the upper surface 591 of such a neutral bus bar 59 .

[0083] Specifically, during the dipping process, the workpiece W is dipped in such a manner that the upper surface 591 is located slightly below the liquid surface 601 of the liquid resin material M0. Fig. 9B As schematically indicated by the middle arrows R91 and R92, the liquid resin material M0 flows from the outer periphery of the neutral bus bar 59 to the upper surface 591 of the neutral bus bar 59. However, if the workpiece W is only immersed in the state, as described above, the viscosity of the liquid resin material M0 is relatively high, so the flow rate is slow, and it takes a relatively long time for the liquid resin material M0 to spread over the entire upper surface 591. In addition, there is also a case where the liquid resin material M0 is difficult to flow to the upper surface 591 due to surface tension. In this case, it takes a relatively long time for the liquid resin material M0 to spread over the entire upper surface 591.

[0084] In contrast, according to the present manufacturing method, by performing the rotating step in the immersed state, the liquid resin material M0 easily flows from the outer peripheral edge of the neutral bus bar 59 to the upper surface 591 of the neutral bus bar 59. Fig. 9B When the workpiece W is rotated in the circumferential direction L1, the flow of the liquid resin material M0 in the direction of the arrow R91 (the flow of the liquid resin material M0 on the upper surface 591 of the neutral line bus bar 59) is promoted. Fig. 9B When the workpiece W is rotated in the circumferential direction L2, the flow of the liquid resin material M0 in the direction of the arrow R92 is promoted (the flow of the liquid resin material M0 on the upper surface 591 of the neutral bus bar 59). As a result, compared with the case where the workpiece W is only immersed in the state of being maintained, the liquid resin material M0 can be efficiently guided to the upper surface 591 of the neutral bus bar 59, and the CT can be reduced.

[0085] In the present manufacturing method, the rotating step in the immersed state can be realized by rotating the workpiece W in only one direction (either the rotation in the circumferential direction L1 or the rotation in the circumferential direction L2), or by rotating the workpiece W in two directions (both the rotation in the circumferential direction L1 or the rotation in the circumferential direction L2). In the case where the rotating step is realized by rotating the workpiece W in two directions, refer to Fig. 9B As described above, the liquid resin material M0 can be guided to the upper surface 591 of the neutral bus bar 59 from both sides of the circumference of the neutral bus bar 59 (see arrows R91 and R92), so that the liquid resin material M0 can quickly spread over the entire upper surface 591 (see Fig. 9C ).

[0086] In addition, in the present manufacturing method, the liquid resin material M0 is efficiently guided onto the upper surface 591 of the neutral bus bar 59 by rotating the workpiece W in the impregnated state around the central axis I, but instead of or in addition to this, the liquid resin material M0 may be efficiently guided onto the upper surface 591 of the neutral bus bar 59 by swinging the workpiece W in the impregnated state, translating the workpiece W, or any combination of swinging and translating. When the workpiece W is translated, the translation may be achieved by keeping the central axis I of the workpiece W parallel to the up-down direction, or by slightly tilting the central axis I of the workpiece W relative to the up-down direction.

[0087] In addition, in the present manufacturing method, regarding the rotation step in the immersed state, the rotation of the workpiece W around the central axis I is achieved by keeping the central axis I of the workpiece W parallel to the vertical direction, but the present invention is not limited thereto. For example, the rotation of the workpiece W around the central axis I can also be achieved by slightly tilting the central axis I of the workpiece W relative to the vertical direction. In this case, the tilt angle can also be changed according to the rotation position and / or rotation angle of the workpiece W.

[0088] In addition, in the present manufacturing method, the rotation angle (rotation stroke) of the rotation process in the immersed state is arbitrary, but is preferably 90 degrees or more, more preferably 180 degrees or more, and may be, for example, 360 degrees. For example, by setting it to 360 degrees or less, even when using a robot with a limited movable range, the rotation process in the immersed state can be realized.

[0089] In addition, in the present manufacturing method, regarding the rotation process in the immersed state, the rotation of the workpiece W around the central axis I is performed in a state where the upper surface 591 of the neutral line bus bar 59 is below the liquid surface 601 of the liquid resin material M0, but it is not limited to this. For example, regarding the rotation process in the immersed state, the rotation of the workpiece W around the central axis I can also be performed in a state where the upper surface 591 of the neutral line bus bar 59 is consistent with the liquid surface 601 of the liquid resin material M0. In addition, the rotation of the workpiece W around the central axis I can also be performed while making the difference in height between the upper surface 591 of the neutral line bus bar 59 and the liquid surface 601 of the liquid resin material M0 (refer to Fig. 9A For example, during the immersion of the workpiece W, the rotation of the workpiece W may be started from a state before the workpiece W is most immersed (for example, H1 = 0 or negative).

[0090] Next, the manufacturing method includes a lifting step (step S210) of slightly lifting the workpiece W from the groove 600. Hereinafter, the lifting step of step S210 is also referred to as a "lifting step to near the liquid surface" to distinguish it from the further lifting described later. In addition, the lifting of the workpiece W can be achieved by the workpiece holding portion 1000 of the manufacturing device. Fig.10 601. The workpiece W in the downward posture after being lifted is schematically shown. The workpiece W in the downward posture after being lifted is impregnated with the liquid resin material M0 (at the bottom of the axial end portion) at the impregnation target portion (at the bottom of the axial end portion). Fig.10 Schematically illustrated by the shaded area M1 in FIG.

[0091] Next, the manufacturing method includes a rotating step (step S211) of rotating the workpiece W in a downward posture slightly lifted from the groove 600 around the central axis I of the workpiece W. In order to distinguish the rotating step of step S211 from other rotating steps, it is also referred to as a "liquid removal rotating step". Fig.11 The rotation performed by the liquid removal rotation step is schematically shown by arrows R11A and R11B.

[0092] The deliquoring rotation process is performed to quickly return the liquid resin material M0 dripping from the impregnation target part of the workpiece W in the downward posture to the tank 600. Specifically, when the workpiece W is lifted from the tank 600, the liquid resin material M0 drips from the impregnation target part of the workpiece W due to its own weight, but the viscosity of the liquid resin material M0 is relatively high, so it drips relatively slowly. In this case, if the liquid resin material M0 to be dripped is waited for to finish dripping while the workpiece W is kept in a downward posture, the CT is likely to increase. In addition, if the workpiece W is kept in a downward posture for a relatively long time, the amount of the liquid resin material M0 that is attached (impregnated) to the impregnation target part of the workpiece W and drips into the tank 600 becomes too large. In this case, in order to ensure the required thickness of the liquid resin material M0, an unnecessary increase in the number of impregnation processes performed on one workpiece W (and the resulting increase in CT) is caused.

[0093] In contrast, in the present manufacturing method, since the liquid removal rotation process is performed, the liquid resin material M0 that can drip from the impregnation target portion of the workpiece W can be separated (divided) into a portion of the liquid resin material M0 remaining on the workpiece W and a portion of the liquid resin material M0 returned to the tank 600 before the liquid resin material M0 finishes dripping from the impregnation target portion of the workpiece W due to its own weight.

[0094] Specifically, in Fig.12 It is shown in Fig.11The state ST2110 on the upper side indicates the state before the de-liquidation rotation process starts, and the state ST2111 on the lower side indicates the state during the de-liquidation rotation process. When the workpiece W is rotated from the state ST2110, as in the state ST2111, a speed difference (speed difference in the rotation direction) is generated between the liquid resin material M0 attached to the impregnation target portion of the workpiece W and the liquid resin material M0 in the tank 600 ( Fig.12 Arrow R2111). If such a speed difference (speed gradient) in the shear direction is generated, the viscosity of the liquid resin material M0 decreases at the boundary portion of the speed difference, so a concave portion is formed in the radial direction between the portion of the liquid resin material M0 attached to the workpiece W and the portion of the liquid resin material M0 in the groove 600. When the concave portion is formed, the free fall of the portion of the liquid resin material M0 below the concave portion is promoted. Therefore, if the workpiece W is further lifted in the state where the concave portion is formed, the liquid resin material M0 attached to the impregnation target portion of the workpiece W and the liquid resin material M0 in the groove 600 can be easily separated (disconnected) using the concave portion as a boundary.

[0095] Thus, according to the present manufacturing method, the liquid removal can be promoted by utilizing the speed difference (speed gradient) in the shear direction by means of the liquid removal rotation process, thereby minimizing the liquid resin material M0 dripping from the impregnation target portion of the workpiece W and shortening the CT. In addition, the number and frequency of the hanging portion M12 (liquid resin material M0 dripping in the form of "icicles") described later can be reduced, and the possibility of the liquid resin material M0 adhering to the stator core 112 can be reduced. As a result, the CT can be shortened.

[0096] In the present manufacturing method, the liquid removal rotation process can be achieved by rotating the workpiece W in only one direction (either rotation toward the circumferential direction L1 side or rotation toward the circumferential direction L2 side), or by rotating the workpiece W in two directions (both rotation toward the circumferential direction L1 side or rotation toward the circumferential direction L2 side).

[0097] In this regard, the inclination direction of the transition portion 54 of the coil piece 52 on the radially outer side and the radially inner side of the coil end portion 114A may also be considered. Fig. 12AThe transition portion 54 of the four radially outer coil pieces 52 is schematically shown, and its inclination direction is the direction in which the upper side is closer to the L2 side than the lower side. In this case, when the workpiece W is rotated toward the circumferential L2 side (refer to arrow R12B), the liquid resin material M0 impregnated between the transition portions 54 tends to flow from the coil end 114A to the axial outside (refer to arrow R12A). In this case, the liquid resin material M0 impregnated between the transition portions 54 may be insufficient. Therefore, in the case of such an inclination direction of the transition portion 54, in order to avoid this undesirable situation, the rotation direction of the deliquescence rotation process can be set to the direction in which the workpiece W is rotated toward the circumferential L1 side.

[0098] In this embodiment, the vertical positional relationship between the workpiece W and the liquid surface 601 when performing the liquid removal rotation process is arbitrary. However, the rising position of the workpiece W in the lifting process to the vicinity of the liquid surface is preferably within the range where the liquid resin material M0 attached to the impregnation object part of the workpiece W is connected (continuous) with the liquid resin material M0 in the tank 600. More specifically, the vertical positional relationship between the workpiece W and the liquid surface 601 when performing the liquid removal rotation process is preferably that the distance between the lower end position of the workpiece W (the lowermost position of the coil end 114A on the lower side) and the liquid surface 601 is preferably less than 10 mm, more preferably less than 5 mm, and most preferably about 1 mm to 3 mm. In addition, if it is greater than 10 mm, the liquid resin material M0 dripping from the coil end 114A is easily scattered outside the tank 600 due to centrifugal force, which is not preferred. On the other hand, if it is less than 1 mm, it is difficult to form the above-mentioned concave portion, which is not preferred.

[0099] In the present production method, the rotation angle (rotation stroke) in the liquid removal rotation step is arbitrary, but is preferably 90 degrees or more, more preferably 180 degrees or more, and may be, for example, 360 degrees.

[0100] Next, the manufacturing method includes a step of changing the posture of the workpiece W further lifted from the groove 600 to an obliquely downward posture (step S212). Fig.13 FIG. 2 schematically shows the state of the workpiece W when the workpiece W is further lifted upward from the height of the workpiece W during the liquid removal rotation process (after the lifting process to near the liquid surface). Fig.14 Schematically shows the state of the workpiece W in a diagonally downward posture.

[0101] In the present manufacturing method, as described above, the liquid-removing rotation step can reduce the dripping of the liquid resin material M0 due to its own weight, but the dripping of the liquid resin material M0 due to its own weight may occur. Fig.13 and Fig.14In the figure, the liquid resin material M0 dripping due to its own weight is represented by the reference symbol M12. Hereinafter, the liquid resin material M0 dripping due to its own weight in the liquid resin material M0 impregnated in the impregnation target part of the workpiece W is referred to as the hanging portion M12, and the other portion is referred to as the normal portion M13. The hanging portion M12 is a so-called "icicle"-like shape, and due to the relatively high viscosity of the liquid resin material M0, there is a tendency not to fall immediately (that is, there is a tendency to maintain the "icicle" shape and extend downward). In addition, in Fig.14 In FIG. 1 , a dashed line H indicates a horizontal line.

[0102] Next, the manufacturing method includes a rotating step (step S213) of rotating the workpiece W around the central axis I of the workpiece W. Hereinafter, in order to distinguish the rotating step of step S213 from other rotating steps, it is also referred to as a "reattachment rotating step". Fig.15 The rotation of the reattachment rotation process is schematically shown by arrow R15.

[0103] The reattachment and rotation step includes rotating the workpiece W in such a manner that the hanging portion M12 is absorbed by the normal portion M13 (integrated by being attached to the normal portion M13). That is, the reattachment and rotation step includes rotating the workpiece W in such a manner that the liquid resin material M0 (i.e., the hanging portion M12) hanging downward from one circumferential position of the impregnation target portion is attached to another circumferential position of the impregnation target portion.

[0104] Here, refer to FIG. 16A to FIG. 16C The principle of the reattachment rotation step and the like will be described. FIG. 16A to FIG. 16C is schematically shown along Fig.15 A plan view of the workpiece W when observed by arrow V15.

[0105] exist FIG. 16A to FIG. 16C The example shown shows a situation where two hanging parts M12 are absorbed by the normal part M13. Fig.16A When the workpiece W is rotated clockwise in the state shown, Fig. 16B In the state shown in FIG. 1 , the right hanging portion M12 is located at a position overlapping with the normal portion M13 when viewed along the arrow V15. At this time, the workpiece W is also in a downwardly slanting posture (refer to FIG. 1 ). Fig.15 ), but also because the viscosity of the liquid resin material M0 is relatively high, the hanging portion M12 is absorbed by the normal portion M13 from the root side of the hanging portion M12 by the rotation of the workpiece W, and the hanging portion M12 is absorbed by the normal portion M13 as a whole. Fig. 16B When the workpiece W is further rotated clockwise in the state shown, it becomes Fig. 16C In the state shown in FIG. 1 , the left hanging portion M12 is located at a position overlapping with the normal portion M13 when viewed along the arrow V15. At this time, the workpiece W is also in a downwardly slanting posture (refer to FIG. 1 ). Fig.15), however, since the viscosity of the liquid resin material M0 is relatively high, the hanging portion M12 is absorbed by the normal portion M13 from the root side of the hanging portion M12 due to the rotation of the workpiece W, and the entire hanging portion M12 is absorbed by the normal portion M13.

[0106] In this way, if each hanging portion M12 reaches a rotational position overlapping with the normal portion M13 when viewed along the arrow V15, it is absorbed by the normal portion M13 as a whole. As a result, each hanging portion M12 disappears, and it is possible to prevent an undesirable situation when the posture of the workpiece W changes to an upward posture while the hanging portion M12 remains. Specifically, in a state where the hanging portion M12 remains, when the posture of the workpiece W changes to an upward posture in the next step S214, the hanging portion M12 may adhere to the stator core 112. For example, it may adhere to the axial end face 1120 (the upper end face) of the stator core 112. In this case, the liquid resin material M0 attached to the stator core 112 needs to be removed separately using a scraper or the like. In contrast, according to the present manufacturing method, as described above, this undesirable situation can be reduced, and a shortening of CT can be achieved.

[0107] In addition, according to the present manufacturing method, each hanging portion M12 is not removed from the workpiece W, but is returned to the impregnation target portion of the workpiece W in an integrated manner with the normal portion M13. Therefore, each hanging portion M12 can be eliminated without reducing the amount of liquid resin material M0 impregnated in the impregnation target portion of the workpiece W. Specifically, when each hanging portion M12 is removed from the workpiece W, the liquid resin material M0 attached to (impregnated in) the impregnation target portion of the workpiece W is reduced accordingly. In this case, in order to ensure the required thickness of the liquid resin material M0, an unnecessary increase in the number of impregnation steps performed on one workpiece W (and the resulting increase in CT) is caused. In contrast, according to the present manufacturing method, this undesirable situation can be prevented and a shortening of CT can be achieved.

[0108] In the present manufacturing method, the reattachment rotation step can be achieved by rotating the workpiece W in only one direction (for example, either clockwise rotation or counterclockwise rotation in the view of arrow V15), or by rotating the workpiece W in two directions. In addition, the rotation angle (rotation stroke) of the reattachment rotation step is arbitrary, preferably 90 degrees or more, and more preferably 180 degrees or more.

[0109] In addition, here, the description is mainly about the hanging portion M12 generated from the coil end portion 114A, but the same effect can be obtained also with respect to the similar hanging portion M12 generated from the neutral bus bar 59 by the reattachment and rotation process.

[0110] In addition, in the present manufacturing method, in the reattachment rotation step, the workpiece W in the oblique downward posture may still be located above the groove 600 in a manner facing the groove 600 in the vertical direction. That is, the workpiece W in the oblique downward posture may be formed in a manner such that the impregnation target portion of the workpiece W overlaps with the groove 600 when viewed from the vertical direction. In this case, even if the hanging portion M12 is separated from the workpiece W and falls, it can be returned to the groove 600, and a decrease in the yield of the liquid resin material M0 caused by the falling of the hanging portion M12 can be prevented.

[0111] Here, in the present manufacturing method, the reattachment rotation step is performed on the workpiece W in an obliquely downward posture, but the angle α of the obliquely downward posture is preferably Fig.15 ) is relatively small. For example, if the angle α is greater than 45 degrees, then Fig.17 As shown schematically, the hanging portion M12 is easy to fall downward when the workpiece W is rotated (or it is simply rotated while maintaining the icicle shape), and the above-mentioned reattachment becomes difficult. Fig.18 As shown schematically, the hanging portion M12 is easy to adhere to the stator core 112. For example, the hanging portion M12 dripping from a circumferential position below the center axis I is easy to adhere to the axial end face 1120 of the stator core 112 at a position radially outside the slot 23. In addition, the hanging portion M12 dripping from a circumferential position above the center axis I is easy to adhere to the axial end face 1120 and the inner circumferential surface of the stator core 112 at a position radially inside the slot 23. This tendency becomes obvious when the angle α of the oblique downward posture exceeds -20 degrees to the negative side. In addition, the angle α is positive in the direction in which the impregnation object part becomes a downward posture. Therefore, the angle α of the oblique downward posture (refer to Fig.15 ) is preferably less than 45 degrees and greater than -20 degrees.

[0112] Or, from Fig.18A and Fig.18B From the viewpoint shown in FIG. 1 , the lower limit value of the negative angle α of the oblique upward posture can also be determined. Fig.18A and Fig.18B In the example shown, since it is the "oblique upward posture", the sign of the angle α is "negative". Fig.18A and Fig.18B The schematic cross-sectional view (cross-sectional view based on the section passing through the center axis I) of the workpiece W in the oblique upward posture during the reattachment rotation process respectively represents different hanging parts M12 (expressed as "hanging part M12A" and "hanging part M12B" for distinction). Fig.18AThe hanging portion M12A shown drips from the upper side of the impregnation target portion (the side axially away from the stator core 112) in the vertical downward direction, and the lower end portion is axially opposite to the non-impregnation target portion (the portion axially close to the stator core 112) in the coil end 114A. In this case, when the hanging portion M12A drips, the liquid resin material M0 adheres to the non-impregnation target portion in the coil end 114A. In order to prevent this adhesion, the negative angle α of the oblique upward posture is preferably set to be smaller than the angle α1 when the hanging portion M12A is axially opposite to the non-impregnation target portion of the coil end 114A (refer to Fig.18A ) is large (close to 0 degrees). In addition, Fig.18B The hanging portion M12B shown drips from the lower side of the impregnation target portion (the side close to the stator core 112 in the axial direction) in the vertical downward direction, and the lower end portion faces the inner peripheral surface of the stator core 112. In this case, when the hanging portion M12B drips, the liquid resin material M0 adheres to the inner peripheral surface of the stator core 112. In order to prevent this adhesion, the negative angle α of the oblique upward posture is preferably set to be smaller than the angle α2 when the hanging portion M12B faces the inner peripheral surface of the stator core 112 in the axial direction (refer to Fig.18B ) is large (close to 0 degrees). Here, the magnitude relationship between the angle α1 and the angle α2 can be changed according to the shape of the coil end 114A, the range of the impregnation target area, etc. Therefore, the negative angle α of the oblique upward posture is preferably set to be greater than the angle of the larger direction of the angle α1 and the angle α2.

[0113] Next, the manufacturing method includes a reversing step (step S214) of changing the posture of the workpiece W to an upward posture. That is, the workpiece W changes from a downward posture to an upward posture via an oblique downward posture. Fig.19 Schematically shows the workpiece W in an upward posture.

[0114] However, if the workpiece W lifted from the slot 600 is not subjected to the above-mentioned reattachment rotation process, but the posture of the workpiece W is reversed up and down through the reversal process (step S214), the hanging portion M12 may adhere to the axial end face 1120 (the upper end face) of the stator core 112. In this case, the liquid resin material M0 attached to the stator core 112 needs to be removed separately with a scraper or the like. In contrast, according to the present manufacturing method, as described above, since the hanging portion M12 is eliminated (absorbed by the normal portion M13) by the reattachment rotation process before the workpiece W is in the upward posture, this undesirable situation can be reduced.

[0115] Next, the manufacturing method includes an upper surface resin curing step (step S216) of performing a resin curing treatment of the liquid resin material M0 on the upper surface of the impregnation target portion of the upward-facing workpiece W. Hereinafter, the resin curing treatment of the upper surface resin curing step is also referred to as "upper surface resin curing treatment".

[0116] In the present manufacturing method, the upper surface resin curing treatment includes irradiating the upper surface of the impregnation target portion of the workpiece W with ultraviolet rays. Fig. 20 The state where the upper surface resin curing process is performed is schematically shown. Fig. 20 In the example shown, the ultraviolet irradiation device 900 irradiates ultraviolet rays (see arrow R13) to the upper surface of the impregnation target portion of the workpiece W. As a result, the upper portion (mainly the upper surface portion) of the liquid resin material M0 impregnated in the impregnation target portion of the workpiece W is cured.

[0117] The ultraviolet irradiation device 900 preferably irradiates ultraviolet rays all around the upper surface of the impregnation target portion of the workpiece W. Thus, the liquid resin material M0 on the upper side can be solidified all around the impregnation target portion. In this case, the workpiece W can be rotated around the central axis I, and the ultraviolet irradiation device 900 can also be rotated. Alternatively, a plurality of ultraviolet irradiation devices 900 can be arranged in a circularly dispersed manner on the upper side of the workpiece W.

[0118] The ultraviolet irradiation device 900 is preferably positioned relative to the workpiece W in such a manner that the optical axis 901 is approximately perpendicular to the upper surface of the impregnation target portion of the workpiece W. That is, the ultraviolet irradiation device 900 is preferably positioned relative to the workpiece W in such a manner that the optical axis 901 is located in an approximately vertical plane. Here, "approximately" is a concept including an error of less than 10%, for example. In addition, the ultraviolet irradiation device 900 is preferably positioned relative to the workpiece W in such a manner that the optical axis 901 passes through the impregnation target portion of the workpiece W, and more preferably, is positioned relative to the workpiece W in such a manner that the optical axis 901 passes near the center of the radial range (range from the innermost diameter position to the outermost diameter position) of the impregnation target portion of the workpiece W. In this case, the liquid resin material M0 in the upper part of the impregnation target portion of the workpiece W can be effectively solidified.

[0119] In this way, according to the present manufacturing method, the upper part (axial end) of the liquid resin material M0 impregnated in the impregnation object part is solidified when the workpiece W is in an upward posture. Therefore, it is possible to reduce the undesirable conditions that may occur when the upper surface resin solidification treatment is performed while the workpiece W lifted from the groove 600 is kept in a downward posture. Specifically, if the resin solidification treatment is performed on the lower surface of the impregnation object part while the workpiece W lifted from the groove 600 is kept in a downward posture, the liquid resin material M0 impregnated in the impregnation object part of the workpiece W may drip downward and solidify due to its own weight. In this case, the liquid resin material M0 being solidified returns to the groove 600, which may affect the fluidity of the liquid resin material M0 in the groove 600. In contrast, according to the present manufacturing method, the upper surface resin solidification treatment is performed in an upward posture as described above, so that the undesirable conditions can be reduced.

[0120] In addition, according to the present manufacturing method, by solidifying the upper portion (axial end portion) of the liquid resin material M0 impregnated in the impregnation target portion, it is possible to form a rectangular cross-sectional corner portion (see FIG. Figure 5 , hereinafter referred to as "joint edge 122") forms a thin film of liquid resin material M0. That is, even for the joint edge 122 where the liquid resin material M0 is difficult to form due to the influence of the wettability around the coil sheet 52, a film of liquid resin material M0 with a relatively thin thickness can be formed. The joint edge 122 formed with the film of liquid resin material M0 has higher wettability due to the film. In this way, the wettability of the joint edge 122 (the wettability of the liquid resin material M0) can be improved. As a result, in the subsequent second impregnation process (described later), it is easy to ensure the required thickness of the insulating coating layer (the solidified product of the liquid resin material M0) on the joint edge 122 of the coil sheet 52. That is, the second impregnation process can also use the film of liquid resin material M0 formed by the first impregnation process as a base to form a thicker film on the joint edge 122.

[0121] Next, the manufacturing method includes an inner diameter side resin curing process (step S218) in which the inner diameter side resin curing process performs a resin curing process of the liquid resin material M0 on the radial inner side of the impregnation target portion of the workpiece W after being inverted to an upward posture. Hereinafter, in order to distinguish it from the above-mentioned upper surface resin curing process, the resin curing process of the inner diameter side resin curing process is also referred to as "inner diameter side resin curing process".

[0122] In the present manufacturing method, the inner diameter side resin curing treatment includes irradiating the radially inner side of the impregnation target portion of the workpiece W with ultraviolet rays. Fig.21 The state where the inner diameter side resin curing process is performed is schematically shown in FIG. Fig.21In the above example, the ultraviolet irradiation device 900 irradiates ultraviolet rays (see arrow R14) to the radially inner side of the impregnation target portion of the workpiece W. As a result, the radially inner portion (mainly the surface portion) of the liquid resin material M0 impregnated in the impregnation target portion of the workpiece W is cured. In addition, the ultraviolet irradiation device 900 may be the same as the ultraviolet irradiation device 900 used in the above-mentioned upper surface resin curing process.

[0123] The ultraviolet irradiation device 900 preferably irradiates the radially inner side of the impregnation target part of the workpiece W with ultraviolet rays throughout the entire circumference. As a result, the liquid resin material M0 in the radially inner part can be cured throughout the entire circumference of the impregnation target part. In this case, the inner diameter side resin curing process can also be performed in parallel with the upper surface resin curing process. Specifically, the upper surface resin curing process and the inner diameter side resin curing process can also be performed together for each circumferential range divided in the entire circumference of the impregnation target part of the workpiece W. Alternatively, the inner diameter side resin curing process can also be performed before the upper surface resin curing process.

[0124] The ultraviolet irradiation device 900 is preferably positioned relative to the workpiece W in such a manner that the optical axis 901 is approximately perpendicular to the radially inner side surface of the impregnation target portion of the workpiece W. That is, the ultraviolet irradiation device 900 is preferably positioned relative to the workpiece W in such a manner that the optical axis 901 is located in an approximately vertical plane. Here, "approximately" is a concept including an error of less than 10%, for example. In addition, the ultraviolet irradiation device 900 is preferably positioned relative to the workpiece W in such a manner that the optical axis 901 passes through the impregnation target portion of the workpiece W, and more preferably is positioned relative to the workpiece W in such a manner that the optical axis 901 passes near the axial center of the impregnation target portion of the workpiece W. In this case, the liquid resin material M0 on the radially inner side surface portion of the impregnation target portion of the workpiece W can be effectively solidified.

[0125] However, depending on the size of the ultraviolet irradiation device 900 and the radial inner space of the workpiece W, Fig.21 As shown, the ultraviolet irradiation device 900 is positioned relative to the workpiece W so that the optical axis 901 intersects the radially inner side surface of the impregnation target portion of the workpiece W in an oblique direction. In this case, one of the inner diameter side resin curing process and the upper surface resin curing process may also serve as the other.

[0126] When the inner diameter side resin curing step (step S218 ) of the inner diameter side resin curing treatment is completed, the insulation coating step of this time is completed.

[0127] Next, the manufacturing method determines whether the insulation coating process for a workpiece W has been performed a predetermined number of times (twice as an example in the manufacturing method) (step S220). Such a determination can be made by a person or by image processing, etc. If the determination result is "yes", the next step is entered. In other cases, in order to perform the second insulation coating process, the steps S206 to S218 are similarly performed. Fig. 22 2 schematically shows the workpiece W which is turned upside down and in a downward position in step S206 in the second insulation coating process. Then, the workpiece W is subjected to a second dipping process and the like.

[0128] The second insulation coating step may be completely the same as the first insulation coating step. In this case, for example, the control of the manufacturing device can be simplified.

[0129] However, the second insulation coating process preferably has at least an impregnation process that is different from the first insulation coating process. Specifically, the impregnation process in the second insulation coating process has a reduced number of impregnation target parts compared to the impregnation process in the first insulation coating process. That is, the impregnation target part of the second impregnation process can be a part of the impregnation target part of the first impregnation process (a part of the axial end side). In this case, the impregnation target part of the second impregnation process can be a minimum part including the edge 122 of the joint of the coil sheet 52. Thus, an insulation coating layer (a solidified product of the liquid resin material M0) having the necessary functions can be effectively formed using a smaller amount (e.g., a minimum amount) of liquid resin material M0.

[0130] exist Fig. 22 Schematically shows a range Q15 where the impregnation target portion in the second insulation coating step belongs with respect to the range (shaded area M1) of the liquid resin material M0 impregnated in the workpiece W in the first insulation coating step.

[0131] Thus, in the present manufacturing method, the insulation coating step is performed multiple times (twice as an example in the present manufacturing method), thereby ensuring the required thickness of the insulation coating layer (solidified product of the liquid resin material M0) on the joint edge 122 of the coil sheet 52.

[0132] When the second insulating coating step is completed, the manufacturing method includes a heating step (step S222), which heats the workpiece W to solidify the liquid resin material M0 in the entire workpiece W. This heating step has the function of completely solidifying the portion of the liquid resin material M0 that has not been solidified in the above-mentioned various resin solidification steps (for example, the portion that is closer to the inside than the surface). The heating method in the heating step is arbitrary, and can also be achieved by, for example, arranging the workpiece W in a furnace. The liquid resin material M0 impregnated in the impregnation area including the impregnation object area of ​​the workpiece W is completely solidified by heating. As a result, an insulating coating layer of the liquid resin material M0 is formed on the stator coil 114.

[0133] The posture of the workpiece W in the heating process is arbitrary, but is preferably as follows: Fig.23 In addition, Fig.23 Schematically shows a situation where a plurality of workpieces W are arranged in a downward posture and subjected to a heating process. Fig.23 Schematically shows a situation where a part of the workpiece holding portion 1000 of the manufacturing device clamps a plurality of workpieces W, but the workpieces W may also be supported on the table in a manner that the end surface of the stator core 112 abuts against the upper surface of the table (not shown). In addition, in the figure, as an example, heat is radiated to the workpieces W from the bottom (see arrow R17), and the heat radiation direction is arbitrary.

[0134] However, in the upward position during the heating process, the liquid resin material M0 before complete curing may drip downward due to its own weight onto the stator core 112. In this case, the liquid resin material M0 adhering to the stator core 112 needs to be removed separately with a scraper or the like.

[0135] In contrast, in the downward posture, even if the liquid resin material M0 in the process of curing before being completely cured moves downward due to its own weight, it will not reach the stator core 112. In addition, the portion of the liquid resin material M0 that has been cured by the upper surface resin curing treatment and the inner diameter side resin curing treatment functions as a "lower cover", thereby reducing the possibility that the dripping liquid resin material M0 will become an icicle. In other words, the downward movement of the liquid resin material M0 in the process of curing is blocked by the portion of the liquid resin material M0 that has been cured by the upper surface resin curing treatment and the inner diameter side resin curing treatment. In this way, it is possible to prevent the adverse conditions that may occur when the heating process is performed in the downward posture.

[0136] Thus, according to the manufacturing method, by performing the heating process in a downward posture, the liquid resin material M0 can be prevented from dripping onto the stator core 112, and the "lower cover" function of the portion of the liquid resin material M0 solidified in the upper surface resin solidification process and the inner diameter side resin solidification process can be used to reduce the icicle-shaped solidification of the liquid resin material M0 hanging downward. In addition, the same outer diameter side resin solidification process can be performed instead of or on the basis of the inner diameter side resin solidification process.

[0137] Next, refer to Fig.24 , a cooling structure suitable for the rotating electrical machine 1 incorporating the rotating electrical machine stator 10 manufactured by the present manufacturing method will be described.

[0138] Fig.24 1 is a diagram schematically showing an example of a cooling structure, and is a diagram schematically showing a part of a cross-sectional structure of the rotary electric machine 1 .

[0139] exist Fig.24 In the example shown, oil is supplied to the coil ends 114A at both axial ends of the stator coil 114 from the radially outer side and the radially inner side. Specifically, the oil supplied to the housing oil passage 60 of the housing 2 (see arrow R20A) is supplied to the radially outer side of the coil end 114A via the oil hole 62 penetrating toward the radial inner side (see arrow R20). In addition, the oil hole 62 can be arranged on the upper side in the vertical direction to promote the dripping of oil based on gravity. In addition, the oil supplied to the axial oil passage 64 of the rotor shaft 112A (see arrow R21A) is supplied to the radially inner side of the coil end 114A via the oil hole 66 penetrating toward the radially outer side (see arrow R21).

[0140] According to the present manufacturing method, as described above, the coil end 114A of the stator coil 114 is provided with an insulating coating of the liquid resin material M0. The thermal conductivity of the portion of the stator coil 114 to which the insulating coating of the liquid resin material M0 is provided is lower than that of other portions (i.e., portions on which the insulating film 130 becomes the surface). Therefore, if the exposed range of the radially outer side surface of the coil end 114A that is not covered by the insulating coating of the liquid resin material M0 is unnecessarily narrowed, the cooling performance of the oil from the above-mentioned oil hole 62 may be unnecessarily reduced. Similarly, if the exposed range of the radially inner side surface of the coil end 114A that is not covered by the insulating coating of the liquid resin material M0 is unnecessarily narrowed, the cooling performance of the oil from the above-mentioned oil hole 66 may be reduced.

[0141] In this regard, according to the present manufacturing method, as described above, the drooping portion M12 of the liquid resin material M0 impregnated in the impregnation target portion is reduced by the reattachment rotation process, so that even if the workpiece W is in an upward posture later, the liquid resin material M0 on the radial outer side is difficult to drip downward. As a result, the possibility of the exposed range of the radial outer side of the coil end 114A that is not covered by the insulating coating layer of the liquid resin material M0 being unnecessarily narrowed can be reduced. As a result, the cooling performance of the oil from the above-mentioned oil hole 62 on the coil end 114A can be effectively improved.

[0142] Next, refer to Fig.25 and Fig.26 , a further preferred manufacturing method is described.

[0143] Fig.25 It means it can replace the reference Figure 1 A schematic flowchart of an example of another manufacturing method performed in accordance with the above-mentioned manufacturing method.

[0144] Fig.25 The manufacturing method shown is similar to that of reference Figure 1 The manufacturing method is different in that step S2210 and step S2211 are added between step S220 and step S222.

[0145] The present manufacturing method includes an inspection process (step S2210) which determines whether liquid resin material M0 is attached to the axial end face 1120 of the stator core 112 after performing the insulation coating process ("yes" in step S220). The presence or absence of adhesion of the liquid resin material M0 can also be determined based on the image processing results of an image from a camera (not shown) photographing the workpiece W. In this case, the determination can also be achieved by visual inspection, based on a predetermined algorithm, or by using artificial intelligence (machine learning, etc.). In addition, in the case of artificial intelligence, the determination of the determination object area (ROI: Region of Interest) in the image captured by the camera can also be achieved based on artificial intelligence. In this case, only adhesion in a harmful manner (for example, adhesion over a range above a threshold) can be used as the detection object.

[0146] In this inspection process, it is also possible to inspect whether the liquid resin material M0 is attached to a portion other than the axial end face 1120 of the stator core 112 (e.g., the side face of the stator core 112). In addition, the attachment M9 attached to the side face 1122 of the stator core 112 is often also attached to the axial end face 1120, and it is also possible to detect it simultaneously by inspecting the attachment to the axial end face 1120.

[0147] exist Fig.26 Schematically shows the liquid resin material M0 adhering to the axial end surface 1120 of the stator core 112 as the adhering matter M9. Such adhering matter M9 may be generated by the liquid resin material M0 dripping or scattering from the coil end 114A or the neutral line bus bar 59.

[0148] However, in the present manufacturing method, as described above, the possibility of the hanging portion M12 adhering to the stator core 112 can be reduced by the liquid removal rotation step (step S211) and the reattachment rotation step (step S213). However, if the liquid resin material M0 adheres for some reason, it can be detected in the inspection step.

[0149] In the present inspection process, when the attachment of the liquid resin material M0 to the stator core 112 (i.e., the attachment M9) is detected, the present manufacturing method includes a process of removing the attachment M9 (step S2211). The method of removing the attachment M9 is arbitrary, for example, a scraper may be used. However, in the present manufacturing method, since the process of removing the attachment M9 is performed before the heating process (step S222), the attachment M9 is easy to remove, for example, it can also be removed by wiping with a rag or the like. Specifically, even if the attachment M9 is exposed to ultraviolet rays during the ultraviolet irradiation process, it is only solidified to a certain extent and is still in a soft temporary solidified state, which is easier to remove than the fully solidified state based on the heating process. For example, when wiping with a rag or the like, unlike the case of using a scraper, no damage will be caused to the stator core 112 or the like, and the workability is also good.

[0150] Thus, according to the present manufacturing method, by performing the above-mentioned inspection process before the heating process, the liquid resin material M0 attached to the stator core 112 can be easily removed. In particular, in the case where the liquid resin material M0 contains epoxy resin as a main component, it is difficult to remove it using a scraper after curing based on the heating process. In addition, even if it can be removed using a scraper, the cured resin may fly or break, and the removed material (resin residue) may be attached to the workpiece W as a foreign matter. In addition, the workpiece W (especially the stator core 112) may be damaged (harmed) by the scraper. In contrast, according to the present manufacturing method, as described above, by performing the inspection process before the heating process, these undesirable situations can be effectively avoided.

[0151] In addition, in the present manufacturing method, the inspection process (step S2210) and the process of removing the attached matter M9 (step S2211) are performed after the ultraviolet irradiation process (step S216 and step S218) of the second insulation coating process, but they can also be performed before the ultraviolet irradiation process (step S216 and step S218) of the second insulation coating process and after step S214. In this case, the possibility of the liquid resin material M0 being cured (as described above, only cured to a certain extent) by the ultraviolet irradiation of the ultraviolet irradiation process (step S216 and step S218) of the second insulation coating process can be reduced.

[0152] Although each embodiment is described in detail above, the present invention is not limited to a specific embodiment, and various modifications and changes can be made within the scope described in the claims. In addition, all or a plurality of the structural components of the above-mentioned embodiments can also be combined.

[0153] For example, in the present embodiment, as described above, since there is a liquid removal rotation process (step S211) and a reattachment rotation process (step S213), when the workpiece W is reversed from the downward posture after the impregnation process (step S208) to the upward posture (refer to step S214), the liquid resin material M0 that may drip onto the stator core 112 can be reduced or eliminated. Therefore, in the present embodiment, the necessity of irradiating the impregnation target part (for example, the outer diameter side of the impregnation target part) with ultraviolet rays while the workpiece W lifted from the groove 600 is maintained in a downward posture can be reduced or eliminated. However, in a modified example, after the liquid removal rotation process of step S211, a process of irradiating the outer diameter side of the impregnation target part with ultraviolet rays after the workpiece W is slightly raised while maintaining the downward posture can be added. In this case, the subsequent steps S212 and S213 can also be omitted.

[0154] In the above-described embodiment, as a preferred example, both the liquid removal rotation step (step S211) and the reattachment rotation step (step S213) are performed, but the liquid removal rotation step (step S211) may be omitted.

[0155] Description of Reference Numerals

[0156] 1: rotating electrical machine, 10: stator for rotating electrical machine, 40: joint (top end), 114: stator coil, 1140: axial end surface, 112: stator core, 1120: axial end surface, W: workpiece, 52: coil sheet, 59: neutral line bus bar, 600: slot, M0: liquid resin material, I: center axis (stator center axis).

Claims

1. A method for manufacturing a stator for a rotating electrical machine, in, include: A preparation step of preparing a workpiece for mounting a plurality of coil pieces forming a stator coil on a stator core, and joining the respective top ends of one coil piece and another coil piece to each other at one axial end side of the workpiece; an immersion step of immersing the workpiece in a tank of a liquid resin material after the preparation step so that the impregnation target area including the joint area between the tip portions is immersed; and a rotating step of rotating the workpiece after the immersion step at a raised position of the workpiece where the impregnation target portion is separated from the tank; The rotating step includes rotating the workpiece around a workpiece central axis corresponding to a stator central axis in a posture of the workpiece in which the impregnation target portion faces a direction intersecting a vertical direction.

2. The method for manufacturing a stator for a rotating electrical machine according to claim 1, wherein: The rotating step includes rotating the workpiece so that the liquid resin material hanging downward from one circumferential position on the impregnation target site adheres to another circumferential position on the impregnation target site.

3. The method for manufacturing a stator for a rotating electrical machine according to claim 2, wherein: The posture in the rotating step includes a posture in which the impregnation target site faces obliquely downward and an angle between the workpiece center axis and a horizontal plane is 45 degrees or less.

4. The method for manufacturing a stator for a rotating electrical machine according to claim 1, wherein: Liquid resin materials have the property of curing by ultraviolet irradiation. The method for manufacturing a stator for a rotating electrical machine further includes an irradiation step of irradiating the impregnation target portion with ultraviolet rays after the rotating step.

5. The method for manufacturing a stator for a rotating electrical machine according to any one of claims 1 to 4, wherein: The raised position of the workpiece includes a position where the impregnation target portion overlaps the groove when viewed in the up-down direction.

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