Method and device for removing coating from rectangular wire

Abstract

To make it possible to remove an insulating film of a rectangular wire in a longitudinal entire area of a target area without exception with low cost by making the cross-sectional shape of the rectangular wire closer to a rectangular shape in the longitudinal entire area by molding.SOLUTION: A film removal method of a rectangular wire 1a comprises: a first film removal step S2 of removing an insulating film 2(2a) on a first side constituting a cross section of the rectangular wire 1a having a rectangular shape; a second film removal step S3 of removing an insulating film 2(2b) on a second side orthogonal to the first side constituting the cross section of the rectangular wire 1a along with the first side; and a curvature radius reduction step S1 of reducing a curvature radius of a corner 4 between both sides, by molding the rectangular wire 1a with prescribed molding surfaces 11a and 12a before the second film removal step S3 that is implemented later among the first and second film removal steps S2 and S3. Protrusions 13 and 14 which protrude from the molding surfaces 11a and 12a toward the rectangular wire 1a are provided on the molding surfaces 11a and 12a. The protrusions 13 and 14 are provided separately on three or more places separated in a longitudinal direction of the rectangular wire 1a, out of the molding surfaces 11a and 12a.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a coating removal method and a coating removal device for rectangular wires. [Background technology]

[0002] In recent years, in light of environmental issues, there has been an accelerating trend to adopt motors in the drive systems and peripheral devices of vehicles such as electric vehicles and hybrid vehicles. The motors mounted on the vehicles are required to be small in size due to the space available for mounting them, but are often required to have high output in order to improve the drive performance of the vehicle.

[0003] In order to increase the output of a motor, it is necessary to increase the current flowing through the stator coil.On the other hand, in order to efficiently increase the current flowing through the coil under conditions where space is limited, it is conceivable to construct the coil from a rectangular wire (rectangular conductor) that has a roughly rectangular cross section and a relatively high space factor.

[0004] The rectangular wires are arranged in a predetermined order in slots formed at regular intervals in the circumferential direction of the stator core to form three-phase coils. Meanwhile, the rectangular wires are covered with an insulating coating. Therefore, in order to electrically connect the rectangular wires that make up each phase, it is necessary to remove the insulating coating from the ends of the rectangular wires and join the ends of the rectangular wires together.

[0005] Patent Document 1 discloses a method in which a flat wire that has been cut to a predetermined length in advance is rotated around its longitudinal axis while being transported in a predetermined direction, and the insulating coating on the short side and long side of the flat wire is removed in multiple cutting processes arranged along the transport direction, and the corners of the flat wire are chamfered to remove the insulating coating from the entire circumference of the flat wire.

[0006] In addition, in Patent Document 2, a method is proposed in which the part of the conductor member (rectangular wire) to be removed from the coating (insulating coating) is crushed by a punch in one direction perpendicular to the longitudinal direction, the cross-sectional shape of the rectangular wire is shaped in a direction close to a rectangular shape, and then the part of the outer surface of the rectangular wire to be removed from the insulating coating is removed, in order to omit the chamfering by cutting. It is also proposed to perform the above-mentioned crushing process by restraining the part of the rectangular wire located on the longitudinal outside of the part to be crushed by a clamp member. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2015-89837 A [Patent Document 2] JP 2016-21806 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, even when the part to be removed from the insulating coating is crushed with a punch as described in Patent Document 2, it is difficult to shape the cross-sectional shape of the rectangular wire in a direction that approaches a rectangular shape over the entire longitudinal area. That is, while the cross-sectional shape can be made to approach a rectangular shape in the central area of ​​the longitudinal direction of the part crushed by the punch, the conductor inevitably escapes toward the outside in the longitudinal direction in the areas on both ends in the longitudinal direction (the conductor is more likely to flow toward the outside in the longitudinal direction), making it difficult to make the conductor flow toward the corners of the rectangular wire. In Patent Document 2, the crushing process is performed with the part located on the outside of the crushed part in the longitudinal direction restrained by a clamp member, but the current situation is that it is still difficult to effectively suppress the plastic flow of the conductor toward the outside in the longitudinal direction by simply restraining the rectangular wire with a clamp member in this way.

[0009] In view of the above circumstances, the technical problem to be solved in this specification is to make it possible to remove the insulating coating of the rectangular wire without omissions and at low cost over the entire longitudinal direction of the target area by using mold forming to make the cross-sectional shape of the rectangular wire closer to a rectangular shape over the entire longitudinal direction. [Means for solving the problem]

[0010] The above-mentioned problem is solved by the coating removal method of the flat wire according to the present invention. That is, this coating removal method includes a first coating removal step of removing the insulating coating on the first side of the cross section of the flat wire that is rectangular, a second coating removal step of removing the insulating coating on the second side of the cross section of the flat wire that is perpendicular to the first side together with the first side, and a curvature radius reduction step of forming the flat wire with a predetermined forming surface before the second coating removal step that is performed later among the first and second coating removal steps, to reduce the curvature radius of the corner between both sides, in the coating removal method of the flat wire, the forming surface is provided with a protruding part that protrudes from the forming surface toward the flat wire, and the protruding part is provided at three or more points on the forming surface that are spaced apart in the longitudinal direction of the flat wire.

[0011] In this way, in the method for removing the coating of a rectangular wire according to the present invention, when the rectangular wire is molded on a predetermined molding surface to reduce the radius of curvature of the corner between the long side and the short side that constitute the cross section of the rectangular wire, a protrusion is provided on the molding surface, and the protrusion is provided at three or more locations on the molding surface that are spaced apart in the longitudinal direction of the rectangular wire. In this way, by providing the protrusions at three or more locations on the molding surface, molding is performed by the molding surface with three or more protrusions stuck in the molded part of the rectangular wire. Since the surface layer part of the rectangular wire (the surface layer part of the conductor) is partitioned into multiple areas along the longitudinal direction at the positions where the protrusions are stuck, the plastic flow of the conductor in the longitudinal direction is effectively suppressed in each partitioned part of the surface layer, and the plastic flow of the conductor is directly restricted by the protrusions stuck in the surface layer part of the conductor. Due to the above action, the plastic flow toward the outside in the longitudinal direction from the molded part of the conductor is effectively suppressed. In addition, since the plastic flow outward in the longitudinal direction is suppressed, the plastic flow of the conductor can be directed toward the areas that will become the corners of the rectangular wire, making it possible to form the cross-sectional shape of the rectangular wire into a rectangular shape with high precision over the entire longitudinal direction.

[0012] In the coating removal method for a rectangular wire according to the present invention, the protruding portion may have a shape that tapers toward the tip.

[0013] By making the protrusion tapered in this way, the protrusion can be thrust into the conductor of the rectangular wire, especially the surface layer of the conductor, with a smaller load. If the protrusion can be thrust into the conductor with a relatively small load, the molding surface adjacent to the protrusion can be prevented from interfering with the molding of the rectangular wire, and the rectangular wire can be molded with high precision on the molding surface.

[0014] In addition, in the coating removal method for a rectangular wire according to the present invention, the protrusion may extend in a direction along one side of the flat surface of the rectangular wire facing the protrusion.

[0015] By forming the protrusion in such a manner that it extends along one side of the flat surface of the rectangular wire to be molded (i.e., in a direction perpendicular to the longitudinal direction of the rectangular wire), the surface layer of the conductor is partitioned in a direction perpendicular to the longitudinal direction of the rectangular wire. Therefore, it is possible to more effectively enjoy the effect of the partitioning of the surface layer.

[0016] In the coating removal method for a rectangular wire according to the present invention, the amount of protrusion from the molding surface of the protruding portion may be greater than the thickness dimension of the insulating coating.

[0017] By making the protruding amount of the protrusion larger than the thickness dimension of the insulating coating in this manner, the protrusion can be reliably inserted into the surface layer of the conductor.

[0018] In addition, in the coating removal method for a rectangular wire according to the present invention, the amount of protrusion from the molding surface of the protrusion may be less than or equal to the sum of the larger of the conductor removal allowances in the first and second coating removal steps and the thickness dimension of the insulating coating.

[0019] In this way, by setting the protruding amount of the protrusions taking into consideration the amount of conductor removal allowance in the coating removal process, the puncture marks left on the conductor by the protrusions after molding can be reliably removed in the subsequent coating removal process. This makes it possible to guarantee the appearance quality of the product (coil segment). It also makes it possible to avoid a situation in which a recess remains on the bonding surface between the exposed conductor parts, thereby reducing the bonding area.

[0020] The above-mentioned problem is also solved by the coating removal device of the flat wire according to the present invention. That is, this coating removal device is equipped with a first coating removal device that removes the insulating coating on the first side of the cross section of the flat wire that is rectangular, a second coating removal device that removes the insulating coating on the second side that forms the cross section of the flat wire together with the first side and is perpendicular to the first side, and a curvature radius reduction device that applies die forming to the flat wire with a specified forming surface before the second coating removal process that is performed later among the first and second coating removal processes, thereby reducing the curvature radius of the corner between both sides, and is characterized in that the forming surface of the curvature radius reduction device is provided with a protrusion that protrudes from the forming surface toward the flat wire, and the protrusion is provided at three or more points on the forming surface that are spaced apart in the longitudinal direction of the flat wire.

[0021] In this way, the coating removal device for a rectangular wire according to the present invention relates to a curvature radius reduction device for forming a rectangular wire on a predetermined forming surface to reduce the curvature radius of the corner between the long side and the short side that constitute the cross section of the rectangular wire, and the forming surface is provided with protrusions, and the protrusions are provided at three or more locations on the forming surface that are spaced apart in the longitudinal direction of the rectangular wire. By providing the protrusions at three or more locations on the forming surface in this way, the forming surface is formed with three or more protrusions piercing the formed portion of the rectangular wire. The surface layer of the rectangular wire (surface layer of the conductor) is partitioned into multiple areas along the longitudinal direction at the positions where the protrusions are pierced, so that the plastic flow of the conductor in the longitudinal direction is effectively suppressed in each partitioned portion of the surface layer, and the plastic flow of the conductor is directly restricted by the protrusions pierced in the surface layer of the conductor. Due to the above action, the plastic flow toward the outside in the longitudinal direction from the formed portion of the conductor is effectively suppressed. In addition, since the plastic flow outward in the longitudinal direction is suppressed, the plastic flow of the conductor can be directed toward the areas that will become the corners of the rectangular wire, making it possible to form the cross-sectional shape of the rectangular wire into a rectangular shape with high precision over the entire longitudinal direction. Effect of the Invention

[0022] As described above, according to the method for removing the coating from a rectangular wire of the present invention, the cross-sectional shape of the rectangular wire can be made closer to a rectangular shape over its entire longitudinal direction by molding, making it possible to remove the insulating coating of the rectangular wire over the entire longitudinal direction of the target area without omissions and at low cost. [Brief description of the drawings]

[0023] [Figure 1] 2 is a flowchart showing the steps of a main part of a method for manufacturing a rectangular wire according to an embodiment of the present invention. [Diagram 2] 2 is an XY plan view showing the positional relationship between equipment related to a curvature radius reducing step and equipment related to a short side coating removing step shown in FIG. 1. [Diagram 3] 2 is a YZ cross-sectional view of a portion of the rectangular wire that is molded on a flat molding surface before the curvature radius reducing step shown in FIG. 1 is performed. [Figure 4] 2 is an XZ cross-sectional view of the rectangular wire before the curvature radius reducing step shown in FIG. 1 is performed. [Diagram 5] 2 is an XY cross-sectional view of the rectangular wire before the curvature radius reducing step shown in FIG. 1 is performed. [Figure 6] 2 is a YZ cross-sectional view of a portion of the rectangular wire molded with a flat molding surface after the curvature radius reducing step shown in FIG. 1 is performed. [Figure 7] 2 is an XZ cross-sectional view of the rectangular wire after the curvature radius reducing step shown in FIG. 1 is performed. [Figure 8] 2 is an XY cross-sectional view of the rectangular wire after the curvature radius reducing step shown in FIG. 1 is performed. [Figure 9] 2 is an XY plan view showing the positional relationship between equipment relating to a curvature radius reducing step and equipment relating to a short side coating removing step when the curvature radius reducing step shown in FIG. 1 is being performed. [Figure 10] FIG. 1 is an XY plan view of a rectangular wire illustrating the concept of the short side pre-cutting process. [Figure 11] FIG. 1 is an XY plan view of a rectangular wire illustrating the concept of the long side pre-cutting process. [Figure 12]2 is a YZ cross-sectional view of a portion of the rectangular wire molded with a flat molding surface before the short side coating removal step shown in FIG. 1 is performed. [Figure 13] 2 is a YZ cross-sectional view of a portion of the rectangular wire molded with a flat molding surface before the long side coating removal step shown in FIG. 1 is performed. [Figure 14] 2 is a YZ cross-sectional view of the rectangular wire before the chamfering step shown in FIG. 1 is performed. [Figure 15] 2 is a YZ cross-sectional view of the rectangular wire after the chamfering process shown in FIG. 1 is performed. [Figure 16] 2 is an XZ plan view of a rectangular wire illustrating the concept of the cutting process shown in FIG. 1. [Figure 17] FIG. 2 is a perspective view of the end of the rectangular wire after coating removal and chamfering. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, the details of a method for manufacturing a rectangular wire according to one embodiment of the present invention will be described with reference to the drawings.

[0025] FIG. 1 shows the steps of the main part of the manufacturing method of the rectangular wire. That is, the manufacturing method of the rectangular wire according to this embodiment includes a coating removal process S1 to S4 for removing the insulating coating of the rectangular wire, and a cutting process S5 for cutting the rectangular wire from which the coating has been removed to obtain a rectangular wire. The coating removal process includes a curvature radius reduction process S1, a short side coating removal process S2, a long side coating removal process S3, and a chamfering process S4. Here, the short side coating removal process S2 corresponds to the first coating removal process according to the present invention, and the long side coating removal process S3 corresponds to the second coating removal process according to the present invention. Below, each process S1 to S3 will be mainly described. In the following, the longitudinal direction of the rectangular wire is conveniently defined as the X direction, and in a virtual cross section of the rectangular wire perpendicular to the X direction, the long side direction of the rectangular wire is conveniently defined as the Y direction, and the short side direction is conveniently defined as the Z direction, and the direction will be described.

[0026] (S1) Curvature radius reduction process In this step S1, the radius of curvature of the corners of the rectangular wire is reduced by a predetermined molding before the short side coating removal step S2 and the long side coating removal step S3, which are the subsequent steps. In this embodiment, as shown in FIG. 2, the radius of curvature reduction step S1 is provided on the upstream side of the conveying direction of the long rectangular wire 1, and the short side coating removal step S2, which is the next step, is provided at a predetermined interval P. In addition, although not shown, the long side coating removal step S3 is provided downstream of the short side coating removal step S2 in the conveying direction of the rectangular wire 1, the chamfering step S4 is provided downstream of the long side coating removal step S3 in the conveying direction of the rectangular wire 1, and the cutting step S5 is provided downstream of the chamfering step S4 in the conveying direction of the rectangular wire 1. The intervals P of the series of steps S1 to S5 are all equal, and the process of each step S1 to S5 is performed simultaneously on the processed area (the peeling area 5 described later) of the rectangular wire 1 that is continuous with the same predetermined interval P.

[0027] 3 to 5 are respectively a YZ cross-sectional view, an XZ cross-sectional view, and an XY cross-sectional view of the rectangular wire 1 in the curvature radius reduction step S1. As shown in these figures, in this step S1, a curvature radius reduction device 10 having a long side molding die 11 with a pair of flat long side press surfaces 11a, 11a and a short side molding die 12 with a pair of flat short side press surfaces 12a, 12a is used to press the area (area 5 to be peeled) of the rectangular wire 1 where the insulating coating 2 is to be peeled in the Y direction and the Z direction to perform die forming (see FIG. 3). Here, both the long side press surface 11a and the short side press surface 12a correspond to the forming surface according to the present invention.

[0028] Here, at least one of the long side press surface 11a and the short side press surface 12a is provided with protrusions 13, 14 (see FIG. 3). In this embodiment, the first protrusions 13 are provided at three or more locations, more preferably five or more locations (11 locations in FIG. 4), spaced apart in the X direction on the pair of long side press surfaces 11a. Also, the second protrusions 14 are provided at three or more locations, more preferably five or more locations (11 locations in FIG. 5), spaced apart in the X direction on the pair of short side press surfaces 12a.

[0029] Here, the shape and arrangement of each of the protrusions 13, 14 are, in principle, arbitrary. In this embodiment, the intervals between the first protrusions 13 are all equal. Similarly, the intervals between the second protrusions 14 are all equal. Moreover, all of the first protrusions 13 have the same shape and size. Similarly, all of the second protrusions 14 have the same shape and size.

[0030] In this embodiment, the first protrusion 13 and the second protrusion 14 are both tapered toward the tip (see Figs. 4 and 5). The first protrusion 13 extends along the short direction of the flat surface of the long side of the rectangular wire 1 (flat outer surface of the long side 2a of the insulating coating 2) facing the first protrusion 13, here the Y direction (see Fig. 3). The second protrusion 14 extends along the short direction of the flat surface of the short side of the rectangular wire 1 (flat outer surface of the short side 2b of the insulating coating 2) facing the second protrusion 14, here the Z direction (see Fig. 3). In the example shown in Fig. 3, the first protrusion 13 is formed over the entire Y direction of the long side pressed surface 11a. Similarly, the second protrusion 14 is formed over the entire Z direction of the short side pressed surface 12a.

[0031] Here, it is preferable that the protrusion amount d1 of the first protrusion 13 from the long-side press surface 11a is larger than the thickness dimension t1 of the long side portion 2a of the insulating coating 2 (see FIG. 4). On the other hand, it is preferable that the protrusion amount d1 of the first protrusion 13 is equal to or smaller than the sum of the removal allowance a1 of the conductor 3 in the long-side coating removal step S3 (see FIG. 13) and the thickness dimension t1 of the long side portion 2a of the insulating coating 2. Similarly, it is preferable that the protrusion amount d2 of the second protrusion 14 from the short-side press surface 12a is larger than the thickness dimension t2 of the short side portion 2b of the insulating coating 2 (see FIG. 5). On the other hand, it is preferable that the protrusion amount d2 of the second protrusion 14 is equal to or smaller than the sum of the removal allowance a2 of the conductor 3 in the short-side coating removal step S2 (see FIG. 12) and the thickness dimension t2 of the short side portion 2b of the insulating coating 2.

[0032] The pair of long side press surfaces 11a provided with the first protrusions 13 and the pair of short side press surfaces 12a provided with the second protrusions 14 are used to press the intended peeling region 5 of the rectangular wire 1 in the Y and Z directions to mold the rectangular wire 1 into a shape following the press surfaces 11a, 12a, thereby deforming the conductor 3 so that the surfaces of the corners 4 provided at the four corners of the conductor 3 are aligned with the long side flat surface 3a and the short side flat surface 3b of the adjacent conductor 3. This causes the corners 4 to protrude and the radius of curvature of the corners 4 to decrease (see FIG. 6).

[0033] During the above-mentioned press forming in the Z direction, the first protrusions 13 provided on each long side press surface 11a are inserted into the surface layer of the long side region of the rectangular wire 1, more precisely, into the long side portion 2a of the insulating coating 2 and into the first surface layer 31 of the conductor 3 located directly below the long side portion 2a (see FIG. 7). As a result, the first surface layer 31 of the conductor 3 is partitioned into a plurality of regions along the longitudinal direction at the positions where the first protrusions 13 are inserted, so that the plastic flow of the conductor 3 in the longitudinal direction (X direction) is effectively suppressed in each partitioned portion of the first surface layer 31. In addition, the plastic flow of the conductor 3 in the X direction is directly restricted by the first protrusions 13 inserted into the first surface layer 31 of the conductor 3.

[0034] During the above-mentioned press forming in the Y direction, the second protrusions 14 provided on each short side press surface 12a are inserted into the surface layer of the short side region of the rectangular wire 1, more precisely, into the short side portion 2b of the insulating coating 2 and into the second surface layer 32 of the conductor 3 located directly below the short side portion 2b (see FIG. 8). As a result, the second surface layer 32 of the conductor 3 is partitioned into a plurality of regions along the longitudinal direction at the positions where the second protrusions 14 are inserted, so that the plastic flow of the conductor 3 in the longitudinal direction (X direction) is effectively suppressed in each partitioned portion of the second surface layer 32. In addition, the plastic flow of the conductor 3 in the X direction is directly restricted by the second protrusions 14 inserted into the second surface layer 32 of the conductor 3.

[0035] The action of each of the protrusions 13 and 14 described above suppresses the elongation in the longitudinal direction (X direction) of the rectangular wire 1 during press forming in the Y direction and Z direction. That is, as shown in Fig. 9, during press forming, the equipment for the next process, the short side coating removal process S2 (here, the short side coating removal device 15 having a pair of peeling blade members 16) needs to perform a predetermined processing on the rectangular wire 1 (perform the short side coating removal process S2) while moving in the X direction according to the elongation amount S of the rectangular wire 1 in the longitudinal direction. However, since this elongation amount S is suppressed, the movement amount (following amount) in the X direction is only a small amount according to the elongation amount S. Therefore, the short side coating removal process S2 described later can be performed simultaneously and accurately with the curvature radius reduction process S1. Although not shown, the equipment for the other post-processes S3 to S5 also requires only a small amount of movement in the X direction according to the elongation amount S, so that each of the processes S3 to S5 can be performed simultaneously with the pre-processes S1 and S2 with high accuracy.

[0036] (S6) Short side pre-cut process In addition, in this embodiment, when the forming process of the corner portion 4 by the long side and short side forming dies 11, 12 (curvature radius reduction process S1) is performed, slits 6 are also formed in the short side portion 2b of the insulating coating 2 covering the outer periphery of the rectangular wire 1 (short side pre-cut process S6 shown in FIG. 10). The slits 6 are formed along the width direction of the short side portion 2b (Z direction in this embodiment). The slits 6 are also formed at predetermined intervals in the longitudinal direction of the rectangular wire 1 (X direction in this embodiment). In this embodiment, the second protrusions 14 provided on the short side press surface 12a penetrate the short side portion 2b of the insulating coating 2 by press forming the rectangular wire 1 by the short side press surface 12a, thereby forming the slits 6. Therefore, in most cases, the same number of slits 6 as the second protrusions 14 are formed in the short side portion 2b of the insulating coating 2 (FIGS. 8 and 10). In this case, the region between a pair of cuts 6, 6 (6a, 6b) formed at positions furthest apart in the X direction is defined as the region 5 to be peeled.

[0037] (S7) Long side pre-cut process In this embodiment, when the curvature radius reduction step S1 is performed, slits 7 are also formed in the long side portion 2a of the insulating coating 2 covering the outer periphery of the rectangular wire 1 (long side pre-cut step S7 shown in FIG. 11). The slits 7 are formed along the width direction of the long side portion 2a (Y direction in this embodiment). The slits 7 are also formed at a predetermined interval in the longitudinal direction of the rectangular wire 1 (X direction in this embodiment). In this embodiment, the first protrusions 13 provided on the long side press surface 11a penetrate the long side portion 2a of the insulating coating 2 by press molding the rectangular wire 1 using the long side press surface 11a, thereby forming the slits 7. Therefore, in most cases, the same number of slits 7 as the first protrusions 13 are formed in the long side portion 2a of the insulating coating 2 (FIGS. 7 and 11). In this case, the area between a pair of slits 7, 7 (7a, 7b) formed at the furthest positions in the X direction is defined as the peeling planned area 5.

[0038] (S2) Short side coating removal process In this step S2, a coating removal process is performed on a predetermined region (a region to be peeled 5) of the rectangular wire 1 that has been subjected to a predetermined molding process by a predetermined coating removal device 15. Any coating removal device 15 can be used at this time. For example, as shown in FIG. 12, a peeling blade member 16 is pressed against a portion between a pair of slits 6a, 6b (see FIG. 10) corresponding to the region to be peeled 5 on the short side portion 2b of the rectangular wire 1, and slid in a direction along the short side of the short side portion 2b (here, the Z direction), so that the portion of the short side portion 2b partitioned by the pair of slits 6a, 6b is peeled off and removed from the rectangular conductor 3. The above-mentioned peeling operation (removal operation) is performed on a pair of short side portions 2b that face each other via the conductor 3. At the completion of the above-mentioned removal operation (cutting process), only the short side portion 2b of the insulating coating 2 of the rectangular wire 1 has been removed, as shown in FIG. 13. On the other hand, the long side portion 2 a of the insulating coating 2 is still attached to the long side flat surface 3 a of the conductor 3 .

[0039] In this case, from the viewpoint of reliably removing (peeling) the entire short side portion 2b in the region 5 to be peeled of the insulating coating 2, it is preferable that the cut line L1 is set at a position shifted toward the conductor 3 from the boundary between the insulating coating 2 and the conductor 3. In this case, from the viewpoint of reliably removing the recess 34 formed in the second surface layer portion 32 of the conductor 3 by the second protrusion 14 in the curvature radius reducing step S1, it is preferable that the cut line L1 is set at a position shifted toward the center of the conductor 3 from the bottom of the recess 34 (see FIG. 12). In the case shown in FIG. 12, the position of the blade member 16 with respect to the rectangular wire 1 is set so that the Y-direction position of the blade surface 16a of the blade member 16 coincides with the Y-direction position of the cut line L1. Here, since the corner 4 of the conductor 3 has been made sharp (the radius of curvature has been reduced) in the previous process S1, by peeling off the insulating coating 2 (the short side portion 2b and the portion of the second surface layer 32 in which the recess 34 is formed) at the position of the above-mentioned cut line L1, the insulating coating 2 covering the corner 4 is completely removed (the state shown in Figure 13).

[0040] (S3) Long side coating removal process In this step S3, a coating removal process is performed on a predetermined area (a region 5 to be peeled) of the rectangular wire 1 in which the corners 4 have been chamfered by molding, using a predetermined coating removal device 17. Any coating removal means can be used at this time. For example, as shown in FIG. 13, a peeling blade member 18 is pressed against a portion between a pair of slits 7a, 7b (see FIG. 11) of the long side portion 2a of the rectangular wire 1, and slid in a direction along the long side of the long side portion 2a (here, the Y direction), so that the portion of the long side portion 2a partitioned by the pair of slits 7a, 7b is peeled off and removed from the conductor 3. The above-mentioned peeling operation (removal operation) is performed on a pair of long side portions 2a facing each other via the conductor 3. As a result, the insulating coating 2 in the region 5 to be peeled off of the rectangular wire 1 is removed over the entire circumference (see FIG. 14).

[0041] As in the short-side coating removal step S2, in order to reliably remove (peel off) the entire long side portion 2a in the region to be peeled of the insulating coating 2, the cut line L2 is preferably set at a position shifted toward the conductor 3 from the boundary between the insulating coating 2 and the conductor 3. In addition, in order to reliably remove the recess 33 formed in the first surface layer portion 31 of the conductor 3 by the first protrusion 13 in the curvature radius reduction step S1, the cut line L2 is preferably set at a position shifted toward the center of the conductor 3 from the bottom of the recess 33 (see FIG. 13). In the illustrated example, the position of the blade member 18 with respect to the rectangular wire 1 is set so that the Z-direction position of the blade surface 18a of the blade member 18 coincides with the Z-direction position of the cut line L2.

[0042] (S4) Chamfering process In this step S4, the corners 4 that have been sharpened in the previous step (curvature radius reduction step S1) are chamfered. In this embodiment, the corners 4 of the rectangular wire 1 after the short side coating removal step S2 and the long side coating removal step S3 are chamfered by molding. Any molding device 19 can be used in this case, and for example, as shown in FIG. 14, a pair of molds 20 having molding surfaces 20a that can mold the corners 4 into a predetermined shape by clamping in the direction along the short sides (Z direction) are used. The molding surfaces 20a in this illustrated example are tapered and have a shape that allows C-chamfering of the corners 4.

[0043] The peeling region 5 of the rectangular wire 1 is placed between the pair of molding dies 20, 20 having the above-mentioned configuration, and the pair of molding dies 20, 20 are brought closer to each other in the Z direction (clamped), whereby molding is performed on the corners (corner 4 of the conductor 3) of the rectangular wire 1 by the molding surfaces 20a. As a result, a tapered chamfered portion 8 (first chamfered portion 8a) is formed on the corners 4 (see FIG. 15).

[0044] If some flattening process (cutting, molding) is required for the long side flat surface 3a and the short side flat surface 3b of the conductor 3 as a result of molding the corner 4, the flattening process may be performed after the chamfering step S4. Alternatively, although not shown in the drawings, the flattening process may be performed simultaneously with the chamfering of the corner 4 during the chamfering step S4.

[0045] (S5) Cutting process After removing all of the insulating coating 2 from the necessary areas (areas 5 to be peeled) in the above manner, the removed portions are cut by a predetermined cutting means (e.g., shearing). As a result, a rectangular wire 1a with the conductor 3 exposed at the longitudinal end portions is obtained, as shown in FIG.

[0046] Then, each corner of the conductor 3, specifically, the corner between the tip surface 3c of the conductor 3 located at the tip end side of the rectangular wire 1a and the long side flat surface 3a, and the corner between the tip surface 3c and the short side flat surface 3b are chamfered. As a result, as shown in Fig. 17, a rectangular wire 1a is obtained in which a first chamfered portion 8a is formed between the long side flat surface 3a and the short side flat surface 3b, a second chamfered portion 8b is formed between the tip surface 3c and the long side flat surface 3a, and a third chamfered portion 8c is formed between the tip surface 3c and the short side flat surface 3b.

[0047] The means for forming the second and third chamfered portions 8b, 8c (chamfering means) is arbitrary, and a suitable example is molding. The order in which the chamfered portions 8b, 8c are formed (the order in which the chamfering processes are performed) is also arbitrary, and for example, they may be performed after the cutting step S5 or before the cutting step S5. If they are performed before the cutting step S5, they may be performed simultaneously with the above-mentioned steps S1 to S5.

[0048] After the end of the rectangular wire 1a has been processed as described above, the rectangular wire is subjected to a predetermined bending process or the like to complete the rectangular wire as a coil segment (not shown).

[0049] As described above, in the manufacturing method of the rectangular wire according to the present embodiment, when the rectangular wire 1 is molded on a predetermined molding surface to reduce the radius of curvature of the corner 4, the first protrusion 13 (second protrusion 14) is provided on the long side press surface 11a (short side press surface 12a) as the molding surface, and the first protrusion 13 (second protrusion 14) is provided at three or more locations on the long side press surface 11a (short side press surface 12a) that are spaced apart in the longitudinal direction (X direction) of the rectangular wire 1 (see Figs. 4 and 5). In this way, by providing the first protrusion 13 (second protrusion 14) at three or more locations on the long side press surface 11a (short side press surface 12a), molding is performed by the long side press surface 11a (short side press surface 12a) with three or more first protrusions 13 (second protrusions 14) piercing the molded portion of the rectangular wire 1. The first surface layer portion 31 (second surface layer portion 32) of the conductor 3 is partitioned into a plurality of regions along the longitudinal direction at the position where the first protruding portion 13 (second protruding portion 14) is inserted (see Figs. 7 and 8), so that the plastic flow of the conductor 3 in the longitudinal direction is effectively suppressed in each partitioned portion of the first surface layer portion 31 (second surface layer portion 32). Moreover, the plastic flow of the conductor 3 is directly restricted by the first protruding portion 13 (second protruding portion 14) inserted into the first surface layer portion 31 (second surface layer portion 32) of the conductor 3. Due to the above action, the plastic flow of the conductor 3 outward in the longitudinal direction is effectively suppressed. Furthermore, since the plastic flow outward in the longitudinal direction is suppressed, the plastic flow of the conductor 3 can be directed toward the regions that will become the corners 4 of the rectangular wire 1, so that the plastic flow of the conductor 3 can be directed toward the regions that will become the corners 4 of the rectangular wire 1 not only in the longitudinal center but also on both longitudinal sides of the intended peeling region 5 where the conductor 3 is likely to escape outward in the longitudinal direction. Therefore, according to the coating removal method of this embodiment, it is possible to form the cross-sectional shape of the rectangular wire 1 into a rectangular shape with high precision over the entire longitudinal region.

[0050] In addition, in this embodiment, the first protrusion 13 (second protrusion 14) is tapered toward the tip, so that the first protrusion 13 (second protrusion 14) can be pierced with a smaller load into the conductor 3 of the rectangular wire 1, particularly into the first surface layer 31 (second surface layer 32) of the conductor 3. If the first protrusion 13 (second protrusion 14) can be pierced with a relatively small load in this manner, it is possible to avoid a situation in which the long side press surface 11a adjacent to the first protrusion 13 (the short side press surface 12a adjacent to the second protrusion 14) interferes with the molding of the rectangular wire 1, and it is possible to mold the rectangular wire 1 with high precision.

[0051] 3, in this embodiment, the first protruding portion 13 (second protruding portion 14) is shaped to extend over the entire Y-direction area of ​​the long-side press surface 11a, so that the first surface layer portion 31 (second surface layer portion 32) of the conductor 3 is defined over the entire area in the direction along the long side of the long side portion 2a (the entire area in the direction along the short side of the short side portion 2b). This makes it possible to more effectively enjoy the effect of defining the first surface layer portion 31 (second surface layer portion 32).

[0052] In addition, in this embodiment, the protrusion amount d1 (d2) of the first protrusion 13 (second protrusion 14) from the long-side press surface 11a (short-side press surface 12a) is set to be larger than the thickness dimension t1 (t2) of the corresponding long side portion 2a (short side portion 2b) of the insulating coating 2, so that the first protrusion 13 (second protrusion 14) can reliably pierce the first surface layer portion 31 (second surface layer portion 32) of the conductor 3. This makes it possible to more reliably obtain the above-mentioned effect of suppressing plastic flow.

[0053] In addition, by setting the protrusion amount d1 (d2) of the first protrusion 13 (second protrusion 14) to be equal to or less than the sum of the removal allowance a1 (a2) of the conductor 3 in the long side coating removal step S3 (short side coating removal step S2) and the thickness dimension t1 (t2) of the long side portion 2a (short side portion 2b) of the insulating coating 2, the puncture marks (recesses 33, 34) caused by the protrusions 13, 14 remaining on the conductor 3 after molding can be reliably removed in the subsequent coating removal steps S2, S3. This makes it possible to guarantee the appearance quality of the product (coil segment). In addition, it is possible to avoid a situation in which the recesses 33 remain on the joint surface (e.g., the long side flat surface 3a) between the exposed portions of the conductor 3, reducing the joint area.

[0054] In addition, in this embodiment, the radius of curvature of the corners 4 is reduced and the corners 4 are chamfered by molding, so that the chamfers can be formed on the corners 4 without producing cutting waste. This makes it possible to reliably remove all of the insulating coating 2 in the intended peeling region 5 while reducing costs in terms of both running costs and material costs.

[0055] Although one embodiment of the present invention has been described above, the method for removing the coating from a rectangular wire according to the present invention can also adopt configurations other than those described above without departing from the spirit of the method.

[0056] For example, in the present embodiment, the first protrusion 13 has a shape extending linearly in the cross-sectional long side direction (Y direction) of the conductor 3 (see FIG. 3), but of course other shapes are possible. For example, although not shown, the first protrusion 13 may have a shape extending in a diagonal direction with respect to the Y direction when the long side pressed surface 11a is viewed in a plan view. Alternatively, the first protrusion 13 may have a shape bent in a V-shape when the long side pressed surface 11a is viewed in a plan view. A similar shape can be adopted for the second protrusion 14.

[0057] In the present embodiment, all the first protrusions 13 are exemplified as having the same shape and size, but of course other shapes may be used. For example, the wedge angle of the first protrusions 13 may be increased toward the outside in the longitudinal direction of the region to be peeled 5. Alternatively, the protrusion amount d1 of the first protrusions 13 may be increased toward the outside in the longitudinal direction of the region to be peeled 5. The second protrusions 14 may also have a similar shape and size.

[0058] In addition, in the present embodiment, a case has been exemplified in which protrusions (first protrusion 13 and second protrusion 14) are provided on both the long side press surface 11a and the short side press surface 12a, but only one of the protrusions may be provided on the corresponding press surface (for example, only the first protrusion 13 on the long side press surface 11a). Moreover, the first protrusion 13 may be provided on only one of the pair of long side press surfaces 11a, and the second protrusion 14 may be provided on only one of the pair of short side press surfaces 12a.

[0059] In addition, in the above embodiment, the order of the curvature radius reducing step S1 is illustrated as being performed before both the short side coating removal step S2 and the long side coating removal step S3, but of course this is not limited to this. For example, the order of the curvature radius reducing step S1 can be set arbitrarily as long as it is performed before the subsequent coating removal step, such as after the short side coating removal step S2 and before the long side coating removal step S3.

[0060] In addition, with regard to the chamfering step S4, the present embodiment illustrates a case in which the chamfering step S4 is performed after the short side coating removal step S2 and the long side coating removal step S3, but of course this is not limited to this. For example, although not shown, the chamfering step S4 may be performed after the short side coating removal step S2 and before the long side coating removal step S3. In short, the chamfering step S4 can be performed in any order as long as it is performed after at least one of the coating removal steps S2 (S3) and the curvature radius reduction step S1.

[0061] Furthermore, the order of the short side coating removal process S2 and the long side coating removal process S3 is not limited to the aspect described in the above embodiment. For example, the short side coating removal process S2 may be performed after the long side coating removal process S3, and then the chamfering process S4 may be performed. [Explanation of symbols]

[0062] 1 Flat wire rod 1a flat wire 2. Insulation coating 2a Long side 2b Short side 3 Conductors 3a Long side flat surface 3b Short side flat surface 3c Tip surface 4 Corner 5. Planned peeling area 6,6a,6b Breaks 7,7a,7b Breaks 8,8a,8b,8c Chamfered parts 10 Curvature radius reduction device 11 Long side molding die 11a Long side press surface 12 Short side molding die 12a Short side press surface 13 First protrusion 14 Second protrusion 15 Short side coating removal device 16 Blade member 16a Blade surface 17 Long side coating removal device 18 Blade member 18a Blade surface 19 Mold forming equipment 20 mold 20a Molding surface 31 First surface layer 32 Second surface layer 33,34 Recess a1,a2 Cutting allowance d1,d2 Projection amount L1, L2 cut lines P interval S Elongation (rectangular wire) S1 Curvature radius reduction process S2 Short side coating removal process S3 Long side coating removal process S4 Chamfering process S5 Cutting process S6 Short side pre-cut process S7 Long side pre-cut process t1, t2 thickness dimensions

Claims

1. A first coating removal process for removing an insulating coating on a first side of the rectangular wire that constitutes a cross section of the rectangular wire; a second coating removal step of removing the insulating coating on a second side that constitutes a cross section of the rectangular wire together with the first side and is perpendicular to the first side; A coating removal method for a rectangular wire, comprising a curvature radius reduction step of forming the rectangular wire with a predetermined forming surface to reduce the curvature radius of the corner between the two sides, prior to the second coating removal step which is performed later among the first and second coating removal steps, The molding surface is provided with a protrusion protruding from the molding surface toward the rectangular wire, A method for removing the coating of a rectangular wire, characterized in that the protrusions are provided at three or more locations on the molding surface spaced apart in the longitudinal direction of the rectangular wire.

2. 2. The method for removing a coating from a rectangular wire according to claim 1, wherein the protrusion has a shape tapered toward a tip.

3. The coating removal method for a rectangular wire according to claim 1 or 2, wherein the protrusion extends in a direction along the one side of the rectangular wire that faces the flat surface of the rectangular wire and that belongs to the flat surface of the rectangular wire.

4. 3. The coating removal method for a rectangular wire according to claim 1, wherein the amount of protrusion from the molding surface of the protruding portion is greater than a thickness dimension of the insulating coating.

5. 3. The coating removal method for a rectangular wire according to claim 1 or 2, wherein the amount of protrusion from the molding surface of the protruding portion is equal to or less than the sum of the larger value of the removal allowance of the conductor of the rectangular wire in the first and second coating removal steps and the thickness dimension of the insulating coating.

6. A first coating removal device for removing an insulating coating on a first side of a rectangular wire; a second coating removal device for removing the insulating coating on a second side that constitutes a cross section of the rectangular wire together with the first side and is perpendicular to the first side; a curvature radius reducing device having a predetermined shaping surface for forming the rectangular wire into a curvature radius of the corner between the two sides, The forming surface of the curvature radius reduction device is provided with a protruding portion protruding from the forming surface toward the rectangular wire, A coating removal device for a rectangular wire, characterized in that the protrusions are provided at three or more locations on the molding surface spaced apart in the longitudinal direction of the rectangular wire.

Images