WO2023112603A1 - Production device for coil and production method for coil - Google Patents

Abstract

Disclosed is a production method that is for a coil having an insulating film and that comprises: a preparation step for preparing a plurality of coil materials before application of the insulating film; and an electrodeposition coating step for generating an electric potential difference between a first electrode to which the coil materials are connected and a second electrode in an electro-coating tank, in a state where the coil materials are immersed in the electro-coating tank. In the electrodeposition coating step, positioning of the coil materials and the second electrode is performed such that, with respect to one or more target sites located at the same position among the respective coil materials, the shortest distances between the second electrode and the target sites of the respective coil materials become substantially equal to one another.

Description

Coil manufacturing device and coil manufacturing method

The present disclosure relates to a coil manufacturing device and a coil manufacturing method.

A technique is known in which an insulating film is applied to multiple coils at the same time by electrodeposition coating.

JP 2017-115240 A

However, in the prior art as described above, the positional relationship of the coil material with respect to the electrodes in the electrodeposition tank varies significantly among the coil materials. It is difficult to apply a reduced insulating film.

Therefore, in one aspect, the present disclosure aims to apply an insulating film with reduced variation to each coil material in a relatively short electrodeposition coating time.

According to one aspect of the present disclosure, a method for manufacturing a coil having an insulating film, comprising:
a preparation step of preparing a plurality of coil materials before the insulating film is applied;
An electrodeposition coating step of generating a potential difference between a first electrode connected to the plurality of coil materials and a second electrode in the electrodeposition tank while the plurality of coil materials are immersed in the electrodeposition tank. and including
In the electrodeposition coating step, the plurality of coil materials and the second electrode are arranged in relation to at least one target portion at the same position in the plurality of coil materials, and the target portion and the second electrode between the plurality of coil materials. A method of manufacturing coils is provided in which the coils are positioned with respect to each other such that the shortest distances between the electrodes are substantially the same.

In one aspect, according to the present disclosure, it is possible to apply an insulating film with reduced variation to each coil material in a relatively short electrodeposition coating time.

FIG. 3 is a cross-sectional view along the axial direction of the stator in which coil pieces are assembled to the stator core; FIG. 4 is an explanatory diagram of a coil piece according to an example; FIG. 10 is an explanatory diagram of a coil piece according to another example; 4 is a schematic cross-sectional view of a coil piece; FIG. It is explanatory drawing of a coil manufacturing apparatus and the outline|summary of an electrodeposition coating process. 1 is a schematic plan view showing one work; FIG. It is a figure explaining the conceptual feature which concerns on a 2nd electrode. FIG. 4 is a perspective view schematically showing the relationship between a plurality of works immersed in an electrodeposition tank and a second electrode; 7 is an enlarged view of the periphery of the workpiece in FIG. 6; FIG. FIG. 5 is a diagram showing the relationship between the transition portion and the second electrode; FIG. 10 is an explanatory diagram of an example of a suitable arrangement when two or more rows of works in the Y direction are simultaneously immersed in an electrodeposition tank to perform an electrodeposition coating process. FIG. 5 is an explanatory diagram of a configuration of a second electrode according to a comparative example; It is a figure which shows the analysis result with respect to a comparative example. FIG. 10 is a diagram showing analysis results for Example 1; FIG. 10 is a diagram showing analysis results relating to the difference in film thickness between the central side surface and the opposite side surface of the work; FIG. 5 is an explanatory diagram of a modification of the second electrode of Example 1; FIG. 14 is an explanatory diagram of various parameters relating to the positional relationship between the second electrode and the work in the modified example of FIG. 13; FIG. 10 is an explanatory diagram of another modified example of the second electrode of Example 1; FIG. 10 is an explanatory diagram of a modification of the center side electrode of the second electrode of Example 1; FIG. 10 is an explanatory diagram of another modification of the central electrode of the second electrode of Example 1; FIG. 10 is an explanatory diagram of still another modified example of the central electrode of the second electrode of Example 1; FIG. 11 is a perspective view showing the relationship between a second electrode and a plurality of works in Example 2; FIG. 10 is a diagram showing analysis results for Example 2; FIG. 11 is an explanatory diagram of a modified example of the second electrode of Example 2; FIG. 10 is an explanatory diagram of various parameters related to the positional relationship between the second electrode and the workpiece in Example 2; FIG. 11 is an explanatory diagram of a modification of the center electrode of the second electrode of Example 2; FIG. 11 is an explanatory diagram of a further modified example of the central electrode of the second electrode of Example 2; FIG. 11 is an explanatory diagram of a further modified example of the central electrode of the second electrode of Example 2; FIG. 10 is an explanatory diagram of a modification relating to a configuration that does not have a central electrode;

Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples, and the present invention is not limited to these, and shapes and the like in the drawings may be partially exaggerated for convenience of explanation.

Below, first, the coil manufactured by the coil manufacturing method of the present embodiment will be outlined, and then the coil manufacturing method will be described.

FIG. 1 is an axial cross-sectional view of the stator 10 with the coil pieces 52 assembled to the stator core 112 . FIG. 2A is a front view of one coil piece 52 out of the plurality of coil pieces 52. FIG. In FIG. 2A, one coil piece 52 is shown in a pre-molding state. FIG. 2B is a three-sided view of one coil piece 52' according to another embodiment. FIG. 3 is a schematic cross-sectional view of the coil piece 52. As shown in FIG.

The stator coil 114 includes a U-phase coil, a V-phase coil, and a W-phase coil (hereinafter referred to as "phase coils" when U, V, and W are not distinguished). The proximal end of each phase coil is connected to an input terminal (not shown), and the distal end of each phase coil is connected to the distal end of the other phase coil to form a neutral point. That is, stator coil 114 is star-connected. However, the connection mode of the stator coil 114 may be changed as appropriate according to the required motor characteristics, etc. For example, the stator coil 114 may be delta-connected instead of star-connected.

Each phase coil of the stator coil 114 is configured by connecting a plurality of coil pieces 52 . The coil pieces 52 are in the form of segment coils (segment conductors) obtained by dividing a phase coil into units that are easy to assemble (for example, units that are inserted into two slots 23). As shown in FIG. 3, the coil piece 52 is formed by covering a linear conductor (rectangular wire) 120 having a substantially rectangular cross section with an insulating film 130 . Here, the linear conductor is made of copper as an example. However, in a variant, the linear conductors may be made of other conductor materials such as iron. Also, the cross-sectional shape of the linear conductor may be other than rectangular.

In the example shown in FIG. 2A, one coil piece 52 is formed in a substantially U shape having a pair of linear slot accommodation portions 50 and a transition portion 54 connecting the pair of slot accommodation portions 50. you can The transition portion 54 on the other side in the axial direction (upper side in FIG. 2A) may be formed by molding in the circumferential direction from the state shown in FIG. 2A. A connecting portion 40 that is connected to the connecting portion 40 of the connecting portion 54 of the other coil piece 52 is set at the end portion of the connecting portion 54 on the other side in the axial direction (upper side in FIG. 2A).

When assembling the coil pieces 52 to the stator core 112, the pair of slot housing portions 50 are inserted into the slots 23 between the teeth 22 (see FIG. 1). In this case, the coil segments 52 can be assembled axially, for example.

A plurality of slot accommodating portions 50 of the coil pieces 52 shown in FIG. Accordingly, a plurality of transition portions 54 extending in the circumferential direction are arranged in the radial direction at both ends of the stator core 112 in the axial direction. In addition, the transition portion 54 forms a coil end.

Note that the coil pieces 52 may be wound around the stator core 112 in the form of lap winding, for example. In the example shown in FIG. 2A, the lower transition portion 54 has offset portions 521B that are radially offset by one layer away from each other.

In the example shown in FIG. 2B, one coil piece 52' is formed by connecting a segment conductor 52A on one side in the axial direction and a segment conductor 52B on the other side in the axial direction.

The segment conductor 52A and the segment conductor 52B may each be formed in a substantially U-shape having a pair of linear slot accommodation portions 50 and a connecting portion 54 connecting the pair of slot accommodation portions 50.

In the example shown in FIG. 2B, the segment conductor 52A and the segment conductor 52B can each be coupled to one of the slot accommodating portions 50 on both sides in the circumferential direction, while the other is one layer in the radial direction. offset away from each other by Specifically, the segment conductor 52A and the segment conductor 52B respectively include offset portions 521A and 521B at the top of the facing surface 42, and the offset portions 521A and 521B provide opposite radial offsets.

As shown in FIG. 2B, the segment conductor 52A and the segment conductor 52B that constitute one coil piece 52' are connected to one of the slot housing portions 50 on both sides in the circumferential direction. The parts 40 are joined together. In this case, the slot accommodating portion 50 on the other side is coupled to another coil piece 52 . At this time, the connecting portions 40 have facing surfaces 42 that face each other in the radial direction and are in surface contact with each other.

Although FIGS. 1 to 3 show the stator core 112 and the stator coil 114 having specific structures, the structures of the stator core 112 and the stator coil 114 are arbitrary as long as the stator coil 114 has the insulating film 130. Moreover, the winding method of the stator coil 114 is also arbitrary, and a winding method other than the above-described lap winding, such as wave winding, may be used.

Next, the coil manufacturing method of this embodiment will be described in detail with reference to FIG. 4A onward.

The coil manufacturing method of this embodiment first includes a preparatory step of preparing a coil material before the insulating film 130 is applied and after molding. The coil material after molding is obtained by, for example, bending a linear conductor. The formed coil material may be partially formed, such as the coil piece 52 shown in FIG. 2A, or may be segmented, such as the coil piece 52' shown in FIG. 2B. Molding may be completed into a configuration corresponding to conductors 52A, 52B. In this embodiment, the coil material (hereinafter also referred to as "workpiece W") prepared in the preparation step has a substantially U-shaped configuration, as shown in FIG. 4B.

The coil manufacturing method of this embodiment includes an electrodeposition coating step of applying the insulating film 130 to the work W prepared in the preparation step by electrodeposition coating. Other steps may be included between the preparation step and the electrodeposition coating step.

The portion of the workpiece W to be coated with the insulating film 130 may be the entire workpiece W or a part of the workpiece W. In this embodiment, as an example, the target portion of the workpiece W to which the insulating film 130 is applied is substantially the entire workpiece W (for example, the entire portion of the coil piece 52 excluding the portion corresponding to the coupling portion 40).

FIG. 4A is an explanatory diagram of the outline of the coil manufacturing apparatus 1 and the electrodeposition coating process. FIG. 4B is a schematic plan view showing one workpiece W. FIG.

The coil manufacturing apparatus 1 includes an electrodeposition bath 70, an electrode section 73, and an electrodeposition processing section 78, as shown in FIG. 4A.

The electrodeposition bath 70 is filled with paint. In addition, in FIG. 4A, the paint filled in the electrodeposition tank 70 is schematically indicated by a hatched area 72 . The paint is a material of the insulating film 130, and may be an insulating paint containing polyamide-imide resin, polyimide resin, or the like. A plurality of workpieces W are immersed in the electrodeposition tank 70 before the insulating film 130 is applied and after the molding.

The electrode part 73 forms a first electrode 74 electrically connected to the plurality of works W and a second electrode 76 in the electrodeposition bath 70 while the plurality of works W are immersed in the electrodeposition bath 70 . do.

The electrodeposition processing section 78 includes a DC power supply (rectifier) 781 and generates a potential difference between the first electrode 74 and the second electrode 76 .

The electrodeposition coating process is performed with the workpiece W immersed in the electrodeposition bath 70 as shown in FIG. 4A. The workpiece W immersed in the electrodeposition tank 70 is in a state before the insulating film 130 is formed on the coil pieces 52 described above. Below, when a specific portion of the workpiece W is indicated, the corresponding portion of the coil piece 52 may be described. For example, in FIG. 4B, a portion of the work W denoted by reference numeral 60 corresponds to the transition portion 54 of the coil piece 52, and is also simply referred to as the transition portion 54 of the work W hereinafter.

When a potential difference is generated between the first electrode 74 and the second electrode 76 while the work W is immersed in the electrodeposition tank 70, a direct current is generated through the paint (coating film component electrophoreses). . As a result, a coating film (coating film) is deposited (electrodeposited) on the surface of the workpiece W immersed in the electrodeposition tank 70 . The paint film formed in this way becomes the insulating film 130 . The first electrode 74 is directly connected to the workpiece W, the second electrode 76 is arranged in the electrodeposition bath 70, and a DC power source 781 is provided between the first electrode 74 and the second electrode 76. are electrically connected. The positive electrode side (and the negative electrode side accordingly) of the first electrode 74 and the second electrode 76 is arbitrary. Also, during the electrodeposition coating process, the paint in the electrodeposition bath 70 may have flow. For example, during the electrodeposition coating process, paint may be supplied to the electrodeposition tank 70 from a supply side pipe (not shown) and discharged from a discharge side pipe (not shown). In this case, the paint is circulated through the electrodeposition bath 70 .

In addition, in FIG. 4A, the second electrode 76 is schematically shown as a conceptual diagram, and the features of this embodiment will be described below. In the following, the conceptual features of the second electrode 76 will first be described with reference to FIG. 5, and then, in FIG. (Embodiment 1 and subsequent embodiments to be described later) will be described separately.

FIG. 5 is a diagram for explaining conceptual features of the second electrode 76. FIG. FIG. 5 conceptually shows a plurality of works W immersed in the electrodeposition tank 70 . Note that the plurality of works W have the same form.

The second electrode 76 is configured so that the plurality of works W have substantially the same positional relationship with respect to the plurality of works W when the plurality of works W are immersed in the electrodeposition tank 70 . Here, with regard to the positional relationship between the second electrode 76 (the same applies to the second electrodes 76A to 76J described below) and the plurality of works W, the phrase "substantially the same positional relationship" means that the plurality of works Regarding parts at the same position in W (hereinafter also referred to as "target parts"), the variation in the shortest distance between the target part and the second electrode 76 among the plurality of works W may be less than 5 mm. . For example, in the example shown in FIG. 5, the shortest distance L1 between the target portion indicated by the arrow P1 and the second electrode 76 is uniquely determined for each workpiece W. As shown in FIG. The shortest distance L1 is the spatial shortest distance through the paint in the electrodeposition bath 70, but it does not have to be measured precisely, and may be, for example, a distance intended by design. The same applies to the shortest distances L2 and L3 related to the other target parts indicated by the arrows P2 and P3. Such a target site is at least a part of the range to be electrocoated, and may be any site (for example, a target site indicated by arrow P2 or arrow P3), or a specific part. may be the part of For example, the target site may be any site within a range W2 mainly including the slot housing portion 50 as shown in FIG. 4B. In this embodiment, as a preferred example, the target portion is an arbitrary portion within the range to be electrocoated (that is, the entire work W). Variation in the shortest distance is, for example, the difference between the minimum and maximum values of the shortest distance L1 of each of the plurality of works W when the plurality of works W are immersed in the electrodeposition tank 70 .

By the way, in the electrodeposition coating process, the work W is more likely to be electrodeposited with the paint on the portion with the relatively high electric flux density than the portion with the relatively low electric flux density, and therefore the film thickness of the paint tends to increase. There is Even a portion having a relatively high electric flux density at the start of the electrodeposition coating process will have a relatively low electric flux density as the coating film thickness increases with the passage of time. When the duration of the state of being immersed in the water (time of the electrodeposition coating process) becomes relatively long, the film thickness of the entire work W becomes uniform.

Therefore, in order to apply the insulating film 130 with reduced variation to one target portion of each work W, it is necessary to reduce the variation between the electric flux densities related to the one target portion of each work W, It is effective to lengthen the time of the electrodeposition coating process (electrodeposition coating time).

Here, the electric flux density related to one target portion of each work W correlates with the shortest distance between the second electrode 76 and the one target portion of each work W. That is, the electric flux density associated with one target portion of the work W tends to increase as the shortest distance becomes shorter.

Therefore, with regard to the target portions of the plurality of works W, by making the variation in the shortest distance between the target portions and the second electrode 76 relatively small among the plurality of works W, the electrodeposition coating time can be shortened. , variation in the thickness of the insulating film 130 applied to the target portion of each workpiece W can be reduced.

Regarding the variation in the shortest distance between the target portion and the second electrode 76 among the plurality of works W, the allowable upper limit varies depending on the required quality. Variation can be effectively reduced. Therefore, the allowable upper limit is preferably about 5 mm as described above, more preferably 3 mm or less, and even more preferably 1 mm or less.

Here, when the target portions of the plurality of works W are within the range W2 and the range W1 in FIG. 4B, as shown in FIG. It is preferably located between the slot accommodation portions 50 . In this case, variations in the thickness of the insulating film 130 can be reduced in relatively large portions within the range W2 and the range W1.

[Example 1]
6 and 7 are explanatory diagrams of the coil manufacturing apparatus 1 and the manufacturing method according to Example 1, and FIG. 6 shows the relationship between a plurality of works W immersed in the electrodeposition tank 70 and the second electrode 76A. FIG. 7 is a schematic perspective view, and FIG. 7 is an enlarged view of the periphery of the workpiece W in FIG. 6. FIG. In FIGS. 6 and 7 (similar to FIG. 13 and the like below), mutually orthogonal X, Y, and Z axes are defined, and with regard to the Z axis, the Z1 side and Z2 side along the Z direction are defined. It is The Z direction (an example of the third direction) corresponds to the vertical direction, and the Z1 side and Z2 side respectively correspond to the upper side and the lower side. FIG. 8 is an enlarged view of the transition portion 54 (offset portion 521B) and its surroundings viewed in the X direction (an example of the second direction), showing the relationship between the transition portion 54 and the second electrode 76A.

6 and 7 (similarly to FIG. 13 and the like), the above-described first electrode 74 and the electrodeposition processing unit 78 are omitted, but the first electrode 74 and the electrodeposition processing unit 78 are It is assumed that they are similarly provided in the manner shown in FIG. 4A.

In the examples shown in FIGS. 6 and 7, a plurality of works W are immersed at the same time. Specifically, for example, the plurality of works W are immersed in a manner lined up in the Y direction (an example of the first direction). In the examples shown in FIGS. 6 and 7, the workpieces W form one row in the Y direction, but may form two or more rows offset from each other in the X direction. In the following, unless otherwise specified, one row of works W in the Y direction will be described, but the same may be true for works W in other rows in the case of two or more rows. This also applies to the second embodiment and subsequent embodiments, which will be described later. 6 and 7 show a state in which the workpiece W is immersed in the electrodeposition tank 70 (state in which the electrodeposition coating process is being performed). This also applies to the subsequent FIG. 13 and the like. Further, the positional relationship between the work W and the second electrode 76A, which will be described below, is the positional relationship when the electrodeposition coating process is performed.

In Example 1, the second electrode 76A includes a central electrode 761A arranged along the Y direction. The center-side electrode 761A is arranged on the center side of the plurality of works W in the X direction. That is, the central electrode 761A is positioned between a pair (two) of the slot accommodating portions 50 in the X direction with respect to the plurality of works W. As shown in FIG. At this time, the central electrode 761A is positioned so as to overlap the plurality of works W when viewed in the X direction. As a result, as described above with reference to FIG. 5, it is possible to effectively reduce the variations in shortest distance between the plurality of works W described above. That is, the positional relationship of the second electrode 76A with respect to each of the plurality of works W becomes substantially the same, and the variation in the shortest distance between the plurality of works W can be effectively reduced.

The central electrode 761A is preferably positioned at an intermediate position between the pair of slot accommodating portions 50 along the X direction. In this case, in each of the plurality of works W, the positional relationship of the central electrode 761A with respect to the pair of slot accommodation portions 50 is substantially the same, and the film thickness of the insulating film 130 applied to the pair of slot accommodation portions 50 varies (same variation within the workpiece) can be effectively reduced.

Note that the central electrode 761A may be formed of a plurality of pieces overlapping in the Y direction, as shown in FIG. In this case, the central electrode 761A may be set for each workpiece W such that one piece corresponds to one workpiece W, or one piece corresponds to a plurality of workpieces W. and may be set for each of a plurality of workpieces W. Alternatively, the central electrode 761A may be formed from one piece common to all the works W in a line.

The center-side electrode 761A faces the bridge portions 54 of the plurality of works W from both sides in the Y direction. Specifically, as shown in FIGS. 7 and 8, the central electrode 761A has a groove portion 76210 through which the bridge portion 54 is passed at the lower end portion. The groove portion 76210 is formed over the entire X-direction of the lower end portion of the center electrode 761A in a downwardly open manner. In this case, wall portions 76211 on both sides of the groove portion 76210 in the Y direction face the transition portion 54 passed through the groove portion 76210 from both sides in the Y direction.

According to such a central electrode 761A, a relatively short shortest distance (see the shortest distance D in FIG. 8) can be achieved with respect to the transition portions 54 of the plurality of works W, and the transition portions 54 (especially the offset portions 521B) can be can effectively increase the electric flux density.

By the way, a bent portion such as the offset portion 521B of the transition portion 54 (for example, a portion where the flatwise side is formed and bent) has the same shortest distance as a straight portion (for example, the slot accommodation portion 50). Also, the electric flux density tends to be low, and therefore the paint tends to be difficult to be electrodeposited. In addition, due to the unevenness of the surface due to the bent portion (the portion that is formed and bent), it tends to be difficult for the coating to be uniformly electrodeposited.

In this regard, according to the present embodiment, the center electrode 761A has the groove 76210 through which the bridge portion 54 is passed, so that the shortest distance between the second electrode 76A (center electrode 761A) and the bridge portion 54 is D can be set appropriately. For example, the shortest distance D between the second electrode 76A (center-side electrode 761A) and the connecting portion 54 is the shortest distance between the second electrode 76A (center-side electrode 761A) and the slot accommodating portion 50 ( (see shortest distance L1)). As a result, the insulating film 130 having a required thickness can be applied to the bridge portion 54 as well. In addition, since the center electrode 761A can be brought close to the bridge portion 54 from multiple directions (that is, from both sides in the Y direction and from the upper side), the thickness of the insulating film 130 applied to the bridge portion 54 can be made uniform. be able to.

FIG. 9 is an arrangement suitable for performing the electrodeposition coating process by simultaneously immersing works W in two or more rows in the Y direction (there are two or more rows in the Y direction along the X direction) in the electrodeposition tank 70. FIG. 4 is an explanatory diagram of an example; FIG. 9 shows a plurality of works W forming two rows in the Y direction in a top view.

As shown in FIG. 9, a plurality of works W may be immersed in the electrodeposition bath 70 in a manner separated from each other by a distance A, which is the shortest distance in top view. In this case, the distance A, which is the work pitch, may preferably be set between 1 mm and 100 mm. As a result, it is possible to optimize the number of works W that can be immersed in the electrodeposition tank 70, and to prevent problems that may occur when the works W are too close to each other (for example, uneven electric flux density). In FIG. 9, three workpieces W are arranged in two rows for each row, but these numbers can be changed as appropriate.

Next, the effects of this embodiment will be further described with reference to FIGS. 10A to 11. FIG.

10A and 10B are explanatory diagrams of the configuration of the second electrode 76A' according to the comparative example, and FIG. 10A schematically shows the relationship between the work W immersed in the electrodeposition tank 70 and the second electrode 76A'. and FIG. 10B is a diagram showing analysis results for a comparative example, and calculation of the thickness (film thickness) of the insulating film 130 applied to the transition portions 54 of three works W arranged in the Y direction. FIG. 10 is a table for comparing values; FIG. In FIG. 10B, each calculated value is shown by a bar graph in association with three works W(1), W(2), and W(3).

In the comparative example, as shown in FIG. 10A, the second electrodes 76A' are arranged on the side walls of the electrodeposition bath 70 (side walls on both sides in the Y direction in FIG. 10A). The second electrode 76A' has a flat plate shape and extends in the XZ plane so as to overlap each workpiece W when viewed in the Y direction. In the comparative example, three workpieces W arranged in the Y direction are arranged in the center between the two second electrodes 76A' in the Y direction.

In such a comparative example, the variation in the shortest distance between the target portion (in this case, the transition portion 54) and the second electrode 76A' substantially corresponds to the inter-work distance in the Y direction. That is, among the three works W arranged in the Y direction, the two works W on both sides in the Y direction have substantially the same shortest distance (shortest distance to the second electrode 76A'). One workpiece W in the middle has a shortest distance larger than the two workpieces W on both sides in the Y direction by the distance between the workpieces in the Y direction.

The results shown in FIG. 10B were obtained when the distance between works in the Y direction was set to 5 mm. In FIG. 10B, reference numerals 101 and 103 denote calculated values of the thickness of the insulating film 130 for the two works W(1) and (3) on both sides in the Y direction, and reference numeral 102 denotes one work W (2 ), the calculated thickness of the insulating film 130 is shown. In addition, even in the crossover portion 54 of the same workpiece W, the surface closer to the second electrode 76A′ in the Y direction and the surface farther from the second electrode 76A′ have different film thicknesses. are using.

As can be seen from FIG. 10B, the thickness of the insulating film 130 at the target portion (in this case, the transition portion 54) of the work W(2) in the middle is is significantly lower (eg by a significantly greater reduction than 15 μm) than the same thickness for .

11A and 11B are diagrams showing the analysis results for this embodiment, in which the calculated values of the thickness of the insulating film 130 at each target portion of the work W are shown on the upper side, and the respective thicknesses of the work W are shown on the lower side. A diagram illustrating the target site is shown.

In FIG. 11, four target regions where line segments LA and LD shown on the lower side of FIG. 11 intersect are evaluated. In the upper part of FIG. 11 , the surface (side surface in the X direction) on the edgewise side (denoted as “EW side”) and the surface (side surface in the Y direction) on the flatwise side (denoted as “FW side”) of each target portion are shown. A calculated value of the thickness of the insulating film 130 is shown for each. Further, in FIG. 11, the three target portions where the line segment LA and the line segment LC intersect form the slot accommodating portion 50, and the average value thereof is the calculated value of the line segment LA to the line segment LC. 11 are plotted above. In the upper part of FIG. 11, W(Ref) indicates a calculated value obtained by analyzing a single workpiece W as a reference value, and W(2) indicates a value among three workpieces W arranged in the Y direction. W(1) and W(3) indicate the calculated values for the works W on both sides in the Y direction among the three works W arranged in the Y direction. Three plots of average film thickness, maximum film thickness, and minimum film thickness are associated with each of W(Ref) to W(3).

As can be seen from FIG. 11, in this embodiment, the difference ( variation) is significantly reduced compared to the comparative example. For example, there is no variation exceeding 15 μm. From this, it can be understood from the analysis that the variation in the thickness of the insulating film 130 applied to the target portion of each workpiece W can be reduced by providing the second electrode 76A.

FIG. 12 is a diagram showing the difference in the analysis results of the calculated value of the thickness of the insulating film 130 between the central side surface of the work W and the opposite side surface of the same work W. As shown in FIG. In the lower part of FIG. 12, an arrow R1 indicating the central side surface of the work W and an arrow R2 indicating the opposite side surface of the work W are shown together with a schematic diagram of the second electrode 76A.

In the present embodiment, as described above, the second electrode 76A is the surface (see arrow R1) of the four side surfaces of the slot accommodating portion 50 of the workpiece W on the center side in the X direction of the workpiece W and on the edgewise side. ) in the X direction. Therefore, of the two edgewise side surfaces of the slot accommodating portion 50 of the work W, the side opposite to the center side of the work W in the X direction (that is, the side facing the side wall of the electrodeposition tank 70 in the X direction) The surface of (see arrow R2) tends to be difficult for the paint to be electrodeposited. This can also be seen from the analysis results shown in FIG. That is, in the example shown on the upper side of FIG. The calculated thickness of the insulating film 130 applied to the opposite (R2) side surface is significantly lower (eg, by a reduction significantly greater than 15 μm).

In the following description, the variation (difference) in the thickness of the insulating film 130 that can occur between the center side of the workpiece W in the X direction and the opposite side thereof in the same portion of the workpiece W will be referred to as the "target portion of the workpiece W. It is also referred to as "variation in film thickness between sides in".

FIG. 13 is an explanatory diagram of a modification of the second electrode 76A of the present embodiment described above with reference to FIG. It is a diagram. This modified example is a configuration suitable for reducing variations in film thickness between the side surfaces of the target portion of the work W described above with reference to FIG. 12 .

Specifically, the second electrode 76B according to this modified example differs from the second electrode 76A according to the present embodiment described above with reference to FIG. That is, the second electrode 76B according to the present modification includes a central electrode 761B substantially identical to the central electrode 761A of the second electrode 76A of the present embodiment described above with reference to FIG. and a side electrode 762B.

The pair of lateral side electrodes 762B are arranged on both sides of the plurality of works W immersed in the electrodeposition tank 70 in the X direction. That is, the pair of side electrodes 762B are positioned on both sides of the two slot accommodating portions 50 in the X direction with respect to the plurality of works W immersed in the electrodeposition bath 70 .

The pair of side electrodes 762B are arranged along the Y direction so as to overlap a plurality of works W when viewed in the X direction. The pair of lateral side electrodes 762B may be arranged along the Y direction in such a manner that one corresponds to one workpiece W, as shown in FIG. Alternatively, the pair of side electrodes 762B may be arranged along the Y direction in such a manner that one corresponds to two or more works W. FIG. For example, the pair of lateral electrodes 762B may each be in the form of one piece. In the example shown in FIG. 13, the pair of side electrodes 762B has a circular cross-sectional shape (cross-sectional shape when cut along a horizontal plane), and is in the form of a rod extending vertically with a uniform cross section. be. However, the shape of the pair of side electrodes 762B is arbitrary, and may have, for example, a rectangular cross-sectional shape.

Since such a pair of side electrodes 762B faces the side surface of the work W opposite to the center side in the X direction, it has the function of facilitating the electrodeposition of paint on the opposite side surface. As a result, it is possible to reduce the film thickness variation between the side surfaces of the target portion of the work W described above with reference to FIG. 12 .

FIG. 14 is an explanatory diagram of various parameters relating to the positional relationship (the positional relationship when viewed in the Y direction) between the second electrode 76B and the workpiece W according to this modified example. Various parameters below represent the distance between the second electrode 76B and the workpiece W.

The parameter B is the separation distance (the separation distance along the X direction) between the center electrode 761B and one of the two slot housing portions 50 of the workpiece W, and the parameter B'' is the distance between the center electrode 761B and The distance between the other of the two slot accommodating portions 50 of the workpiece W and the parameter B' is the distance between the lower portion of the slot accommodating portion 50 of the workpiece W (the target portion on the side close to the transition portion 54) and the center side. is the separation distance (the separation distance along the X direction) from the electrode 761 B. The parameter C is the distance between the side electrode 762 B and one of the two slot housing portions 50 of the workpiece W (the closer one). is the distance between them (the distance along the X direction).

In this modification, the relationship between the values of the parameter B and the parameter B' is preferably such that the values of the parameter B and the parameter B' are substantially the same. Specifically, B:B'=0 .01-1:0.01-1, more preferably B:B'=0.1-1:0.1-1, most preferably B:B'=1:1. In addition, the relationship between the values of parameter B and parameter B″ is preferably B:B″=0.01 to 1:0.01 to 1, more preferably B:B″=0.1 to 1:0.1 to 1, most preferably B:B″=1:1. By realizing such a relationship between the values of the parameter B and the parameter B' or B'', it is possible to reduce film thickness variations between different portions of the slot accommodating portion 50 in the same workpiece W.

Further, the relationship between the values of the parameter B and the parameter C is preferably such that the values of the parameter B and the parameter C are substantially the same. Specifically, B:C=0.01 to 1:0. .01-1, more preferably B:C=0.1-1:0.1-1, most preferably B:C=1:1. By realizing such a relationship between the values of the parameter B and the parameter C, it is possible to reduce the film thickness variation between the side surfaces of the target portion of the workpiece W.

Also, in the relationship between parameter B and parameter D (see FIG. 8) described above, the relationship between each value is preferably B:D=1:0.01 to 0.99. By realizing such a relationship between the values of the parameter B and the parameter D, it is possible to reduce film thickness variations between the slot accommodating portion 50 and the transition portion 54 (especially the offset portion 521B) in the same work W. becomes possible.

FIG. 15 is an explanatory diagram of still another modification of the second electrode 76A of the present embodiment described above with reference to FIG. It is a perspective view which shows a relationship. This modified example is a configuration suitable for reducing variations in film thickness between the side surfaces of the target portion of the work W described above with reference to FIG. 12 .

A second electrode 76C according to this modification includes a pair of side electrodes 762C and a central electrode 761A, which is different from the second electrode 76A of the present embodiment described above with reference to FIG. It differs in that it is replaced with an electrode 761C. That is, the second electrode 76C according to this modification includes a central electrode 761C and a pair of side electrodes 762C.

The center-side electrode 761C has a different cross-sectional shape (cross-sectional shape when cut along a horizontal plane) from the center-side electrode 761A of the present embodiment described above with reference to FIG. It has a cross-sectional shape. The central electrode 761C may have the same configuration around the transition portion 54 as the central electrode 761A of the present embodiment described above with reference to FIG. 7 and the like.

The pair of side electrodes 762C may be similar to the pair of side electrodes 762B according to the modification described above with reference to FIG. This modification also provides the same effects as the modification described above with reference to FIG. 13 . Also in this modified example, the relationship of various parameters shown in FIG. 14 may be realized.

By the way, the various second electrodes 76A, 76B, and 76C described above may be vertically movable with respect to the electrodeposition tank 70, and after setting a plurality of works W during the electrodeposition coating process, It is preferably set in the electrodeposition bath 70 . However, the side electrodes 762B and 762C of the second electrodes 76B and 76C may be supported on the electrodeposition tank 70 side.

FIG. 16 is an explanatory diagram of a modification of the central electrode 761A of the second electrode 76A of the present embodiment described above with reference to FIG. It is a two-sided view showing the relationship between.

In this modified example, the center electrode 761D is arranged on the center side of the plurality of works W in the X direction in such a manner that the lower end is supported by the bottom portion 702 of the electrodeposition tank 70 . At this time, the center electrode 761D is positioned so as to be close to the plurality of works W in the Y direction. In the example shown in FIG. 16, the central electrodes 761D are arranged in such a manner as to form a pair (two pairs) for each workpiece W while being slightly offset in the X direction and sandwiching the bridge portion 54 in the Y direction. there is In this case, the positional relationship of the center electrode 761D becomes substantially the same for each of the plurality of works W, and the variation in the shortest distance between the plurality of works W can be effectively reduced. Further, in this case, the center electrode 761D can face the bridge portions 54 of the plurality of works W from both sides in the Y direction. As a result, the electric flux density of the transition portion 54 can be effectively increased in the electrodeposition coating process. Note that the distance between the center electrode 761D and the transition portion 54 may be the same as the shortest distance D (parameter D) described above.

Also in this modified example, the central electrode 761D is preferably positioned at an intermediate position between the pair of slot accommodating portions 50 along the X direction. In this case, in each of the plurality of works W, the positional relationship of the central electrode 761D with respect to the pair of slot accommodating portions 50 is substantially the same, and the film thickness of the insulating film 130 applied to the pair of slot accommodating portions 50 varies (same variation within the workpiece) can be effectively reduced.

Note that the central electrode 761D shown in FIG. 16 may be realized in combination with the side electrodes 762B and 762C described above.

FIG. 17 is an explanatory diagram of another modification of the central electrode 761A of the second electrode 76A of the present embodiment described above with reference to FIG. It is a two-sided view showing the relationship with W.

In this modified example, the center electrode 761E is arranged on the center side of the plurality of works W in the X direction in such a manner that the lower end is supported by the bottom 702 of the electrodeposition bath 70 . At this time, the center electrode 761E is positioned between the plurality of works W in the Y direction. In the example shown in FIG. 17, the central electrode 761E has a flat plate shape and extends vertically between the plurality of works W in the Y direction. In this case, the positional relationship of the center electrode 761E is substantially the same for each of the plurality of works W, and the variations in shortest distance between the plurality of works W can be effectively reduced. Further, in this case, the center electrode 761E can face the bridge portions 54 of the plurality of works W from both sides in the Y direction. As a result, the electric flux density of the transition portion 54 can be effectively increased in the electrodeposition coating process. Note that the distance between the central electrode 761E and the transition portion 54 may be the same as the shortest distance D (parameter D) described above.

Also in this modified example, the central electrode 761E is preferably positioned at an intermediate position between the pair of slot accommodating portions 50 along the X direction. In this case, in each of the plurality of works W, the positional relationship of the central electrode 761E with respect to the pair of slot housing portions 50 is substantially the same, and the film thickness of the insulating film 130 applied to the pair of slot housing portions 50 varies (same variation within the workpiece) can be effectively reduced.

Note that the central electrode 761E shown in FIG. 17 may be realized in combination with the side electrodes 762B and 762C described above.

FIG. 18 is an explanatory diagram of still another modification of the central electrode 761A of the second electrode 76A of the present embodiment described above with reference to FIG. 2 is a two-sided view showing the relationship between the 1 and the workpiece W. FIG.

In this modified example, the center electrode 761F is arranged on the center side of the plurality of works W in the X direction in such a manner that the lower end is supported by the bottom 702 of the electrodeposition bath 70 . At this time, the center electrode 761F is positioned between the plurality of works W in the Y direction. In this case, the positional relationship of the center electrode 761F becomes substantially the same for each of the plurality of works W, and the variation in the shortest distance between the plurality of works W can be effectively reduced. In the example shown in FIG. 18, the center electrode 761F has a flat plate shape, but unlike the center electrode 761E shown in FIG. 17, the cross-sectional shape differs depending on the position in the vertical direction. Specifically, the central electrode 761F has a relatively large dimension in the X direction in a section (vertical section) facing the bridge portions 54 of the plurality of works W when viewed in the Y direction. In this case, the central electrode 761F can efficiently increase the electrode area facing the bridge portions 54 while facing the bridge portions 54 of the plurality of workpieces W from both sides in the Y direction. As a result, it is possible to effectively increase the electric flux density of the transition portion 54 (especially the offset portion 521B) in the electrodeposition coating process. The distance between the central electrode 761F and the transition portion 54 may be the same as the shortest distance D (parameter D) described above.

Also in this modified example, the central electrode 761F is preferably positioned at an intermediate position between the pair of slot accommodating portions 50 along the X direction. In this case, in each of the plurality of works W, the positional relationship of the central electrode 761F with respect to the pair of slot housing portions 50 is substantially the same, and the film thickness of the insulating film 130 applied to the pair of slot housing portions 50 varies (same variation within the workpiece) can be effectively reduced.

Note that the central electrode 761F shown in FIG. 18 may be realized in combination with the side electrodes 762B and 762C described above.

[Example 2]
Next, the second electrode configuration according to Example 2 will be described with reference to FIG. 19 onward.

By the way, the workpiece W is provided with the insulating film 130 to finally form the coil piece 52. In the coil piece 52, insulation between different phases is provided at the portion (the transition portion 54) forming the coil end. From the viewpoint of improving the properties, it is desirable that the insulating film 130 is relatively thick. On the other hand, it is desirable that the insulating film 130 of the coil piece 52 is relatively thin in the slot accommodating portion 50 that is accommodated in the slot 23 from the viewpoint of increasing the occupancy of the conductor in the slot 23 .

Therefore, in the second electrode configuration according to the present embodiment, the thickness of the insulating film 130 applied to the transition portion 54 of the work W is significantly larger than the thickness of the insulating film 130 applied to the slot accommodation portion 50. is configured to be In this case, when the thickness of the insulating film 130 applied to the slot housing portion 50 is 1.0, the thickness of the insulating film 130 applied to the transition portion 54 is 1.1 or more. 2.0 (i.e. doubled) or greater. The boundary position between the relatively thick range and the relatively thin range of the insulating film 130 does not need to strictly match the boundary position between the transition portion 54 and the slot accommodating portion 50 . , may slightly deviate from the boundary position between the transition portion 54 and the slot accommodation portion 50 . For example, the thickness of the insulating film 130 applied to the lower portion of the slot accommodating portion 50 may be relatively large, similar to the thickness of the insulating film 130 applied to the transition portion 54 .

FIG. 19 is a perspective view showing the relationship between the second electrode 76G and a plurality of works W of this embodiment. The present embodiment differs from the second electrode 76A according to the first embodiment described above mainly in the form of the center electrode 761G (configuration of the lower end). The layout of the center electrode 761G may be the same as the layout of the center electrode 761A according to the first embodiment.

Specifically, the central electrode 761G of this embodiment has a base portion 7614G and a thick film forming portion 7616G.

The base portion 7614G may have substantially the same configuration as the center electrode 761A according to the first embodiment described above, except for the lower end portion. Specifically, the base portion 7614G is arranged on the center side of the plurality of works W in the X direction. That is, the base portion 7614G is positioned between a pair (two) of the slot housing portions 50 in the X direction with respect to the plurality of works W. As shown in FIG. At this time, the base portion 7614G is positioned so as to overlap the plurality of works W when viewed in the X direction. As a result, as described above with reference to FIG. 5, it is possible to effectively reduce the variations in shortest distance between the plurality of works W described above.

The base portion 7614G is preferably positioned at an intermediate position between the pair of slot accommodation portions 50 along the X direction. In this case, in each of the plurality of works W, the positional relationship of the base portion 7614G with respect to the pair of slot accommodation portions 50 is substantially the same, and the film thickness of the insulating film 130 applied to the pair of slot accommodation portions 50 varies (the same work can effectively reduce the variation within the

The thick film forming portion 7616G continues downward from the lower end portion of the base portion 7614G. The thick film forming portion 7616G overlaps the transition portions 54 of the plurality of works W when viewed in the vertical direction. The thick film forming portion 7616G preferably overlaps substantially the entire crossover portion 54 of the plurality of works W in the X direction when viewed in the vertical direction. Substantially the entire crossover portion 54 in the X direction takes into consideration the X-direction gap (see parameter B′ described later) secured between the workpiece W and the thick film forming portion 7616G at both ends in the X direction. be. Accordingly, the thick film forming portion 7616G is preferably significantly larger in dimension in the X direction than the base portion 7614G.

FIG. 20 is a diagram showing the analysis results for this example, and the target parts to be evaluated are as shown on the lower side of FIG. 11 described above. Of the three target portions where the line segment LA and the line segment LC shown in FIG. does not overlap with On the other hand, the target portion of the line segment LC overlaps the thick film forming portion 7616G when viewed in the X direction. In FIG. 20, among the three target portions where the line segment LC intersects with the line segment LA, the average value of each target portion of the upper line segment LA and the line segment LB is the calculation of the line segment LA and the line segment LB. plotted as values. Also, the average values of the target portions of the line segments LC and LD are plotted as the calculated values of the line segments LC and LD. Further, in FIG. 20, W(Ref) indicates a calculated value obtained by analyzing a single single workpiece as a reference value, and W(2) indicates the center value of the three workpieces arranged in the Y direction. W(1) and W(3) indicate calculated values for the workpiece W, and W(1) and (3) indicate calculated values for the workpieces W on both sides in the Y direction among the three workpieces arranged in the Y direction. Three plots of average film thickness, maximum film thickness, and minimum film thickness are associated with each of W(Ref) to W(3).

As can be seen from FIG. 20, in this embodiment, the difference ( variation) is significantly reduced compared to the comparative example. For example, there is no variation exceeding 15 μm. From this, it can be understood from the analysis that the variation in the thickness of the insulating film 130 applied to the target portion of each workpiece W can be reduced by providing the second electrode 76G.

In addition, as can be seen from FIG. 20, in the present embodiment, by providing the thick film forming portion 7616G, the target portions (targets of the line segment LC and the line segment LD) that take the shortest distance in relation to the thick film forming portion 7616G It can be seen that the thickness of the insulating film 130 applied to the portion) can be effectively increased. That is, from FIG. 20, among the target portions of the workpiece W, the target portions (the target portions of the line segment LC and the line segment LD) having the shortest distance in relation to the thick film forming portion 7616G are the other target portions. The thickness of the insulating film 130 is larger than the target portion, that is, the target portion (the target portions of the line segment LA and the line segment LB) having the shortest distance from the base portion 7614G.

FIG. 21 is an explanatory diagram of a modification of the second electrode 76G of the present embodiment described above with reference to FIG. It is a diagram. This modified example is a configuration suitable for reducing variations in film thickness between the side surfaces of the target portion of the work W described above with reference to FIG. 12 .

Specifically, the second electrode 76H according to this modified example differs from the second electrode 76G according to the present embodiment described above with reference to FIG. That is, the second electrode 76H according to the present modification includes a central electrode 761H substantially identical to the central electrode 761G of the second electrode 76G of the present embodiment described above with reference to FIG. and an electrode 762H. The pair of side electrodes 762H may have the same configuration as the pair of side electrodes 762B described above with reference to FIG. In this case, it is possible to reduce the film thickness variation between the side surfaces of the target portion of the workpiece W described above with reference to FIG. 12 .

FIG. 22 is an explanatory diagram of various parameters relating to the positional relationship (the positional relationship when viewed in the Y direction) between the second electrode 76H and the workpiece W according to the modification shown in FIG.

In FIG. 22, parameters B, B'', and C associated with base portion 7614H may be similar to parameters B, B'', and C described above with reference to FIG.

Parameter B′ is the separation distance (separation distance along the X direction) between the thick film forming portion 7616H and the two slot housing portions 50 of the work W, and the parameter C′ is the side electrode 762H, A separation distance (separation along the X direction distance).

In this modification, the relationship between the values of parameter B and parameter B' is preferably B:B'=1:0.99 to 0.01, more preferably B:B'=1:0. 0.5 to 0.01, more preferably B:B'=1:0.2 to 0.01. Also, the relationship between the values of parameter B and parameter C is preferably B:C=1:0.01-2. Further, the relationship between the values of the parameter C and the parameter C' is preferably C:C'=1:0.99 to 0.01, more preferably C:C'=1:0.5 to 0.01, more preferably C:C'=1:0.2 to 0.01. Also, the relationship between the values of parameter B' and parameter C' is preferably B':C'=1:1 to 0.01. In FIG. 22, the lower portion of the side electrode 762H is offset so as to approach the slot accommodating portion 50 so that C:C'=1:0.2 to 0.01. In this way, the lower portion of the side electrode 762H may be offset from the upper portion toward the slot accommodating portion 50 .

By realizing such a relationship between the values of the parameters B', C', etc., it is possible to reduce film thickness variations between the slot housing portion 50 and the transition portion 54 in the same work W. .

FIG. 23 is an explanatory diagram of a further modification of the second electrode 76G of this embodiment described above with reference to FIG. 19, and shows the relationship between the second electrode 76I of this modification and a plurality of works W. It is a perspective view. This modified example is a configuration suitable for reducing variations in film thickness between the side surfaces of the target portion of the work W described above with reference to FIG. 12 .

A second electrode 76I according to the present modification includes a pair of lateral side electrodes 762I and a center side electrode 761G as opposed to the second electrode 76G of the present embodiment described above with reference to FIG. The difference is that it is replaced with 761I. That is, the second electrode 76I according to this modification includes a central electrode 761I and a pair of side electrodes 762I.

The central electrode 761I differs from the central electrode 761G of the present embodiment described above with reference to FIG. 19 in that it is divided in the Y direction. It is divided into two relationships. Also, the center electrode 761I is different from the base portion 7614G of the center electrode 761G of the above-described embodiment in that the dimension of the base portion 7614I in the X direction is also smaller, but the dimension of the base portion 7614I in the X direction is the same as that of the base portion 7614G of the above-described embodiment. It may be similar to the base portion 7614G of the embodiment. In addition, the central electrode 761I differs from the thick film forming portion 7616G of the central electrode 761G of the present embodiment in that the vertical dimension of the thick film forming portion 7616I is also smaller, but the vertical dimension is , may be the same as the thick film forming portion 7616G of the present embodiment described above.

The pair of side electrodes 762I may be similar to the pair of side electrodes 762H according to the modification described above with reference to FIG. This modification also provides the same effects as the modification described above with reference to FIG. 21 . Also in this modified example, the relationship between various parameters (the positional relationship when viewed in the Y direction) shown in FIG. 22 may be realized.

By the way, the various second electrodes 76G, 76H, and 76I described above may be vertically movable with respect to the electrodeposition tank 70. During the electrodeposition coating process, after setting a plurality of works W, It is preferably set in the electrodeposition bath 70 . However, the side electrodes 762H and 762I of the second electrodes 76H and 76I may be supported on the electrodeposition tank 70 side.

FIG. 24 is an explanatory diagram of a further modification of the central electrode 761G of the second electrode 76G of the present embodiment described above with reference to FIG. It is a front view showing a relationship with.

In this modified example, the central electrode 761J that forms the second electrode 76J is arranged on the center side of the plurality of works W in the X direction in such a manner that the lower end is supported by the bottom 702 of the electrodeposition tank 70. The center-side electrode 761J is divided so that there is one for each workpiece W, similar to the center-side electrode 761I described above with reference to FIG. At this time, the center electrode 761J is positioned between the plurality of works W in the Y direction so as to be close to the plurality of works W in the Y direction. In this case, the positional relationship of the center electrode 761J is substantially the same for each of the plurality of works W, and the variations in shortest distance between the plurality of works W can be effectively reduced.

Also in this modified example, the base portion 7614J of the central electrode 761J is preferably positioned at an intermediate position between the pair of slot accommodating portions 50 along the X direction. In this case, in each of the plurality of works W, the positional relationship of the central electrode 761J with respect to the pair of slot housing portions 50 is substantially the same, and the film thickness of the insulating film 130 applied to the pair of slot housing portions 50 varies (same variation within the workpiece) can be effectively reduced. In the example shown in FIG. 24, the thick film forming portions 7616J of the central electrode 761J are arranged in such a manner that a pair (two pairs) sandwiching the transition portion 54 in the Y direction is formed for each workpiece W. In this case, the central electrode 761J can face the connecting portions 54 of the plurality of works W from both sides in the Y direction. As a result, the electric flux density of the transition portion 54 can be effectively increased in the electrodeposition coating process. Note that the distance between the center electrode 761J and the bridge portion 54 may be the same as the above-described shortest distance D (parameters B' and C').

In addition, in this modified example, the central electrode 761J has portions 7618J that extend vertically from both ends of the thick film forming portion 7616J in the X direction. The portions 7618J are arranged in such a manner that a pair (two pairs) sandwiching the lower portion of the slot housing portion 50 in the Y direction is formed for each workpiece W. The portion 7618J overlaps with the lower portion of the slot accommodating portion 50 when viewed in the Y direction. In this case, the center-side electrode 761J can face the lower part of the slot housing portion 50 of the plurality of works W from both sides in the Y direction. As a result, the electric flux density in the lower portion of the slot housing portion 50 can be effectively increased in the electrodeposition coating process, and the thickness of the insulating film 130 applied to the lower portion of the slot housing portion 50 can be increased. . The distance between the center electrode 761J and the lower portion of the slot accommodation portion 50 may be the same as the shortest distance D (parameters B' and C') described above.

Note that the central electrode 761J shown in FIG. 24 may be realized in combination with the side electrodes 762H and 762I described above.

In the example shown in FIG. 24, the portion 7618J of the central electrode 761J only overlaps the lower portion of the slot accommodating portion 50 when viewed in the Y direction, but in a manner that overlaps substantially the entire slot accommodating portion 50. , may extend further upward. Alternatively, like the central electrode 761K shown in FIG. 25, the portion 7618J that overlaps with the lower portion of the slot accommodating portion 50 when viewed in the Y direction may be omitted. In this case, the central electrode 761K forming the second electrode 76K has a base portion 7614K and a thick film forming portion 7616K. The thick film forming portion 7616K does not overlap the lower portion of the slot accommodating portion 50 when viewed in the Y direction.

Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope described in the claims. It is also possible to combine all or more of the constituent elements of the above-described embodiments. Further, among the effects of each embodiment, the effects related to dependent claims are additional effects distinguished from generic concepts (independent claims).

For example, in each of the embodiments described above, the central electrodes 761A to 761K are provided, but similar effects may be achieved without using central electrodes such as the central electrodes 761A to 761K. For example, second electrodes 76L according to the modification shown in FIG. 26 are provided in pairs on both sides in the X direction, and each have a side electrode portion 762L. The side electrode portion 762L includes a portion 7620L extending to the side of the slot accommodating portion 50 and a portion 7621L extending below the transition portion 54. As shown in FIG. The portion 7620L may have the same function as the side electrodes 762H, 762I and the like described above. The portion 7621L overlaps the transition portion 54 when viewed in the vertical direction, and is the portion of the second electrode 76L that has the shortest distance to the transition portion 54 . In this case as well, the second electrode 76L can be configured to have substantially the same positional relationship with the plurality of works W, as in the above-described embodiments. Note that the shortest distance between the portion 7621L and the transition portion 54 may be set in the same manner as the value of the parameter D (see FIG. 8) described above. The same applies to other parameters (for example, parameter B, etc.). Even with such a modified example, the same effect as the above-described embodiment can be obtained. In addition, in the perspective view shown in FIG. 26, the part 7620L on the front side is shown transparently so that the state of the work W and the like can be easily understood.

Reference Signs List 1... Coil manufacturing apparatus, 70... Electrodeposition tank, 73... Electrode part, 74... First electrode, 76, 76A to 76L... Second electrode, 761A to 761K... Center Side electrodes 762B, 762C, 762H, 762I Side electrodes 78 Electrodeposition treatment section 130 Insulating films 52, 52' Coil pieces (coils) 112 Stator core 114 Stator coil (coil) 7614G Base portion (second electrode portion) 7616G, 7616H Thick film forming portion (first electrode portion) 50 Slot accommodating portion , 54... transition portion (coil end portion), 521B... offset portion (bending portion), W... work (coil material)

Claims (11)

1. A method for manufacturing a coil having an insulating film,
   a preparation step of preparing a plurality of coil materials before the insulating film is applied;
   An electrodeposition coating step of generating a potential difference between a first electrode connected to the plurality of coil materials and a second electrode in the electrodeposition tank while the plurality of coil materials are immersed in the electrodeposition tank. and including
   In the electrodeposition coating step, the plurality of coil materials and the second electrode are arranged in relation to at least one target portion at the same position in the plurality of coil materials, and the target portion and the second electrode between the plurality of coil materials. A coil manufacturing method wherein the coils are positioned relative to each other such that the shortest distances between the electrodes are substantially the same.
2. The coil manufacturing method according to claim 1, wherein in the electrodeposition coating step, the plurality of coil materials and the second electrode are positioned with respect to each other such that the variation in the shortest distance is less than 5 mm.
3. The plurality of coil materials are for a stator coil wound around a stator core, and include two slot accommodating portions accommodated in slots of the stator core in a wound state, and exposed from an axial end surface of the stator core in a wound state. each having a coil end portion that
   The coil manufacturing method according to claim 1 or 2, wherein the target portion includes at least part of the slot accommodating portion and the coil end portion.
4. In the electrodeposition coating step, the plurality of coil materials are arranged in rows in the first direction such that the two slot housing portions and the coil end portions form a U-shape when viewed in the first direction. immersed in the electrodeposition bath,
   the second electrode includes a central electrode arranged along the first direction;
   In the electrodeposition coating step, the central electrode is disposed between the two slot accommodating portions in a second direction intersecting the first direction with respect to the plurality of coil materials immersed in the electrodeposition bath. 4. The coil manufacturing method according to claim 3, wherein the coil material is positioned so as to overlap the plurality of coil materials when viewed in the second direction.
5. 5. The coil manufacturing method according to claim 4, wherein in the electrodeposition coating step, the center electrode is positioned at an intermediate position between the two slot accommodating portions along the second direction.
6. The coil end portion has a bent portion offset in a direction corresponding to the radial direction of the stator core in a wound state,
   the target portion includes at least a portion of the slot accommodation portion and the bending portion;
   5. In the electrodeposition coating step, the shortest distance between the bent portion and the second electrode is smaller than the shortest distance between the target portion of the slot accommodation portion and the second electrode. 5. The coil manufacturing method according to 5.
7. In the electrodeposition coating step, the center electrode faces the bent portions of the plurality of coil materials immersed in the electrodeposition tank from both sides in the first direction, The coil manufacturing method according to claim 6.
8. In the electrodeposition coating step, the central electrode is applied to the plurality of coil materials immersed in the electrodeposition bath,
   a first electrode portion overlapping the coil end portions of the plurality of coil materials when viewed in a third direction perpendicular to both the first direction and the second direction;
   a second electrode portion that overlaps with the slot accommodating portions of the plurality of coil materials when viewed in the second direction;
   In the electrodeposition coating step, the first electrode portion is closer to the coil end portion than the second electrode portion in the third direction, and is larger in dimension in the second direction than the second electrode portion. A method of manufacturing a coil according to any one of claims 4 to 7, wherein the coil is large.
9. The second electrode further includes a pair of side electrodes arranged along the first direction,
   In the electrodeposition coating step, the pair of side electrodes are positioned on both sides of the two slot accommodating portions in the second direction with respect to the plurality of coil materials immersed in the electrodeposition bath. 9. A method for manufacturing a coil according to any one of claims 4 to 8.
10. In the electrodeposition coating step, the separation distance between the pair of side electrodes along the second direction and the two slot accommodating portions is 10. The method of manufacturing a coil according to claim 9, wherein the distance is substantially equal to the separation distance between the slot accommodation portions.
11. An apparatus for manufacturing a coil having an insulating film,
    an electrodeposition tank in which the plurality of coil materials are immersed before the insulating film is applied;
    an electrode part forming a first electrode connected to the plurality of coil materials and a second electrode in the electrodeposition bath while the plurality of coil materials are immersed in the electrodeposition bath;
    an electrodeposition processing unit that generates a potential difference between the first electrode and the second electrode,
    In a state in which the plurality of coil materials are immersed in the electrodeposition bath, the second electrode is provided with respect to at least one target portion at the same position in the plurality of coil materials, the target portion between the plurality of coil materials and the A coil manufacturing apparatus configured so that the shortest distance between the electrodes and the second electrode is substantially the same.

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