JP7346202B2 - Manufacturing method of flat wire - Google Patents

Description

The present invention relates to a method for manufacturing a rectangular wire, and particularly to a technique for sharpening the corners of a rectangular wire.

In recent years, in view of environmental issues, there has been an acceleration in the use of motors in drive units and peripheral equipment of vehicles such as electric cars and hybrid cars. Motors mounted on the vehicles described above are required to be small due to the available mounting space, and are often required to have high output in order to improve the driving performance of the vehicle.

Here, in order to increase the output of the motor, it is necessary to increase the value of the current flowing through the stator coil. On the other hand, in order to efficiently increase the current value flowing through the coil under space-restricted conditions, it is necessary to use a rectangular wire (flat conductor wire) whose cross section is as close to a rectangle as possible and has a relatively high space factor. It is conceivable to configure the following.

Here, the flat wire is usually manufactured by drawing out a conductive wire with a perfect circular cross section from a drawer drum using a winding drum and supplying it between a pair of rolling rolls to form the conductive wire into a rectangular cross section. (For example, see Patent Document 1). The conducting wire formed into a rectangular cross-section is coated with a known insulating material such as enamel, for example by baking, thereby producing a rectangular wire in which the periphery of the conducting wire having a rectangular cross-section is covered with an insulating coating.

Japanese Patent Application Publication No. 6-246319

Incidentally, recently, efforts have been made to further increase the space factor of the coil in order to further improve motor performance. Regarding rectangular wires, methods are being considered to improve the space factor by making the corners of the rectangular wires more acute (closer to right angles). Here, since the rectangular wire is formed into a rectangular cross-section by two pairs of rolling rolls, it is conceivable to repeat rolling with the rolls described above in order to further sharpen the corner portions. However, repeating the rolling operation increases manufacturing costs and is therefore not a very preferable method. In addition, when forming a conductive wire into a rectangular cross-section by rolling with rolls as described above, a step of forming an insulating film is required after forming, but generally speaking, the more acute the corner, the more uniform the film thickness. It becomes difficult to form an insulating coating around the conductor. For these reasons as well, there is a risk that processing costs will increase in order to form a uniform insulating film.

Therefore, for example, we purchase covered conductor wires, which are made by covering conductor wires with an insulating coating around a conductor wire with a perfect circular cross section or a conductor wire with a large curvature at the corner of the cross section, as inexpensive distribution materials. One possible method is to form the conducting wire into a rectangular cross-section by rolling it. However, with this method, not only the conducting wire but also the insulating coating is rolled, so the insulating coating is excessively stretched along with the conducting wire in the longitudinal direction of the covered conducting wire. In this case, there is a concern that the insulating coating, which has poor ductility compared to the conducting wire (copper wire in many cases), may cause defects such as cracks during rolling or during bending after rolling.

In view of the above circumstances, in this specification, while preventing cracking of the insulation coating due to excessive stretching in the longitudinal direction, the corners of the conductive wire that will become a rectangular wire are sharpened at low cost, thereby improving the space factor. The technical problem to be solved is to achieve this goal.

The above-mentioned problem is solved by a method for manufacturing a rectangular wire according to the present invention. That is, this manufacturing method includes a cross-sectional rectangularizing step of rectangulating the cross-sectional shape of the flat wire material, thereby obtaining a flat wire having a rectangular cross-sectional shape. While moving the wire material relatively in its longitudinal direction, the outer circumferential surface of the rectangular wire material is pressed from four directions by the first pressing section to produce a protruding deformation between the four surfaces of the outer circumferential surface that are pressed by the first pressing section. The outer circumferential surface of the flat wire material that has undergone the projecting deformation is pressed from four directions by a second pressing section whose pressing surface shape is different from that of the first pressing section, so that the flat wire material has a rectangular cross section. It is characterized by having a rectangular forming step.

As described above, in the method for manufacturing a rectangular wire according to the present invention, by subjecting the rectangular wire material to two types of plastic working, it is possible to make the corners sharper while suppressing elongation in the longitudinal direction. That is, in the present invention, first, the outer circumferential surface of the rectangular wire material is pressed from four directions to cause protruding deformation between the four pressed surfaces of the outer circumferential surface. As a result, plastic flow due to the pressing occurs mainly between the surfaces to be pressed by the first pressing part among the outer circumferential surfaces of the rectangular wire material, and as a result, protruding deformation occurs between the surfaces to be pressed. Therefore, by forming this protrudingly deformed rectangular wire material into a rectangular cross-section in the second pressing section, the protrudingly deformed section having sufficient plastic flow allowance is crushed, and the rectangular wire material that has undergone this protruding deformation is crushed by the pressing surface of the second pressing section. It flows in a direction that fills the empty space between the divided area and the outer peripheral surface of the flat wire material. As a result, it is possible to form a rectangular wire with a shape that follows the area divided by the pressing surface, that is, a shape that has four flat surfaces and an acute corner section between each flat surface. . In addition, in the protrusion deformation process, after the rectangular wire material is deformed protrudingly in four directions, the protruding deformation part is crushed and reshaped to flatten it, thereby actively promoting plastic flow within the cross section. On the other hand, plastic flow (elongation) in the longitudinal direction can be sufficiently suppressed or prevented as much as possible. Moreover, since the corner portion can be sharpened with high precision by performing plastic working twice, it is possible to suppress an increase in manufacturing cost due to an increase in the number of man-hours. As described above, according to the present invention, it is possible to make the corners of a rectangular wire acute at low cost while preventing cracking of the insulating coating due to elongation in the longitudinal direction.

Further, in the method for manufacturing a flat wire according to the present invention, in the protruding deformation step, the outer circumferential surface of the flat wire material is rolled by two pairs of rolls serving as the first pressing portion, each of which has a convex drum-shaped pressing surface. In addition to producing a protruding deformation between the four pressed surfaces, in the rectangular forming process, the rectangular wire material is The flat wire material may be formed into a rectangular cross-section by rolling the outer peripheral surface.

In this way, in the protruding deformation process, by rolling the outer peripheral surface of the rectangular wire material with two pairs of rolls as the first pressing part, each of which has a convex pressing surface, it is possible to avoid excessive loads on the conductor or the insulation coating. Alternatively, it is possible to smoothly generate a protruding deformation portion while avoiding stress concentration. Therefore, in the rectangular forming process, by rolling the outer peripheral surface of the rectangular wire material with two pairs of rolls, each of which has a cylindrical pressing surface with a constant outer diameter, it is possible to stably reproduce the sharpening of the corner portion. becomes possible.

Further, in the method for manufacturing a flat wire according to the present invention, in the protruding deformation step, the four flat surface portions provided on the outer periphery of the flat wire material are pressed from four directions by the first pressing portion, so that the adjacent flat surface portions are pressed from four directions by the first pressing portion. A protruding deformation may be caused in a total of four round corner portions located between the two.

As described above, according to the method for manufacturing a flat wire according to the present invention, the four flat surface portions provided on the outer periphery are pressed from four directions to form the four round corner portions located between the adjacent flat surface portions. By causing the protruding deformation, it becomes possible to perform various plastic workings of the rectangular wire material very efficiently and to form it into a rectangular shape. Therefore, it is possible to manufacture a rectangular wire with sharp corners at a low cost by using a rectangular wire that is available at a low price as a material, and thereby it is possible to improve the space factor at a low cost. .

As described above, according to the present invention, while preventing cracking of the insulating coating due to excessive stretching in the longitudinal direction, the corners of the conductive wire that will become a rectangular wire can be made acute at low cost, thereby improving the space factor. It becomes possible to aim for.

1 is a flowchart showing the main steps of a method for manufacturing a rectangular wire according to an embodiment of the present invention. 1 is a side view showing the overall configuration of a cross-sectional rectangularization device according to an embodiment of the present invention. 3 is a sectional view taken along line AA of the rectangular wire material shown in FIG. 2. FIG. FIG. 3 is a sectional view taken along line BB of the protruding deformation device shown in FIG. 2; 3 is a sectional view taken along the line CC of the rectangular forming apparatus shown in FIG. 2. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, the content of the manufacturing method of the rectangular wire based on one Embodiment of this invention is demonstrated based on drawing.

FIG. 1 shows the main steps of a method for manufacturing a rectangular wire. That is, the method for manufacturing a rectangular wire according to the present invention includes a cross-sectional rectangularization step of rectangulating the cross-sectional shape of a rectangular wire material, and the cross-sectional rectangularization step, in this embodiment, includes a protrusion deformation step S1, It has a rectangular shape forming step S2. Hereinafter, after explaining the overall configuration of the apparatus used in the cross-sectional rectangularization process, details of each process S1 and S2 will be explained.

As shown in FIG. 2, the cross-sectional rectangularization device 10 includes a transport device 20 that transports the rectangular wire material 1 in a predetermined direction, and performs protrusion deformation processing on the rectangular wire material 1 being transported by the transport device 20. and a rectangular forming apparatus 40 for performing rectangular forming on the rectangular wire material 1. In this case, the transport device 20 and the projection deformation device 30 can perform the projection deformation step S1, and the transport device 20 and the rectangular shape forming device 40 can perform the rectangular shape forming step S2.

Here, the conveying device 20 can be arbitrarily configured as long as it can convey the flat wire material 1 in a predetermined direction, and in this embodiment, it is a drawer for pulling out the long flat wire material 1 from a wound state. It is composed of a drum 21 and a winding drum 22. Then, the drawer drum 21 and the winding drum 22 are arranged so that the protruding deformation process S1 and the rectangular shape forming process S2 can be sequentially performed on the rectangular wire material 1 which is stretched between the drawer drum 21 and the winding drum 22. 21, a winding drum 22, a protrusion deformation device 30, and a rectangular shape forming device 40 are arranged at predetermined positions.

The flat wire material 1 used here has a substantially rectangular cross section as shown in FIG. It has a corner part 1c provided between 1b and 1b. Here, the rectangular wire material 1 integrally includes a conducting wire 2 formed of a conductor such as copper, and an insulating coating 3 that covers the periphery of the conducting wire 2. Therefore, both the flat surface portions 1a and 1b and the corner portion 1c described above are formed of the insulating coating 3. Further, in this embodiment, the corner portion 1c is a round corner portion having an arcuate cross section, and the radius of curvature thereof is, for example, 0.5 mm or more and 1.0 mm or less. Further, the ratio of the radius of curvature to the dimension in the width direction of the flat wire material 1 is, for example, 0.1 or more and 0.5 or less, and the ratio of the radius of curvature to the dimension in the thickness direction is, for example, 0.1 or more and 0.5 or less. It is. Of course, the numerical values listed here are merely examples, and corner portions having an arcuate cross section that fall outside the above numerical range are not intended to be excluded from the round corner portion according to the present invention. In addition, the width direction dimension here means the direction along the long side when the cross section of the flat wire material 1 has a rectangular shape (including a substantially rectangular shape) as shown in FIG. means the direction along the short side.
(S1) Protrusion deformation process

In the protruding deformation step S1, the outer circumferential surface 4 of the rectangular wire material 1 is pressed from four directions by the protruding deforming device 30 while the rectangular wire material 1 is moved in its longitudinal direction by the conveying device 20, so that the outer circumferential surface 4 is deformed in a protruding manner. A protruding deformation is caused between the four pressed surfaces 4a (see FIG. 4) by the device 30. In this embodiment, the protrusion deformation device 30 used here is a pair of rolling rolls that sandwich and press a pair of flat surface portions 1a, 1a on the long sides of the rectangular wire material 1, as shown in FIG. 31, 31, and a pair of rolling rolls 32, 32 that sandwich and press a pair of flat surface portions 1b, 1b, which are the short sides of the rectangular wire material 1. In this case, the two sets of rolling rolls 31 and 32 correspond to the first pressing section according to the present invention.

Here, the pressing surfaces 31a and 32a of each of the rolling rolls 31 and 32 are both located at the center of the corresponding flat surface portions 1a and 1b (for the flat surface portion 1a on the long side, it is the center in the width direction; 1b, the outer diameter dimension is maximum at the center in the thickness direction). In this embodiment, each of the pressing surfaces 31a and 32a are both shaped like a convex drum. Moreover, the rotational axes X1 and X2 of each of the rolling rolls 31 and 32 are set in a direction parallel to the width direction or thickness direction of the corresponding flat surface portions 1a and 1b, respectively. The distance between the mutually parallel rotation axes X1, X1 and the distance between the rotation axes X2, X2 are kept constant.

The protrusion deformation step S1 using the protrusion deformation device 30 having the above configuration is performed, for example, as follows. That is, as shown in FIGS. 2 and 4, the rectangular wire material 1 drawn out from the drawing drum 21 is supplied between the rolling rolls 31 and 32 of each set, which is the processing area of the protruding deformation device 30, and The rolling rolls 31 and 32 are rotated around predetermined rotation axes X1 and X2. As a result, the rectangular wire material 1 is rolled by each set of rolling rolls 31 and 32 while moving in a predetermined direction. Here, the outermost diameter portions of the rolling rolls 31 and 32 of each set are both lower than the flat surface portions 1a and 1b of the flat wire material 1 before rolling (positions indicated by two-dot chain lines in FIG. 4). 1, the flat surface portions 1a and 1b of the rectangular wire material 1 supplied between each set of rolling rolls 31 and 32 are not pressed (rolled) by the rolling rolls 31 and 32. A plastic flow is generated toward the corner portion 1c where there is no plastic flow. As a result, as shown in FIG. 4, the flat surface portions 1a, 1b are plastically deformed into shapes corresponding to the pressing surfaces 31a, 32a of the rolling rolls 31, 32, and are provided between the adjacent flat surface portions 1a, 1b. Projecting deformation portions 1d are generated at a total of four corner portions 1c (in this embodiment, round corner portions having a large radius of curvature relative to the thickness dimension and width direction dimension). Note that the rolling allowance by each set of rolling rolls 31 and 32 at this time is appropriately set according to the required size of the protruding deformation portion 1d.

(S2) Rectangular shape forming step In the rectangular shape forming step S2, the outer peripheral surface of the rectangular wire material 1 is moved by the conveying device 20 in the longitudinal direction of the rectangular wire material 1 in a state in which the four protruding deformed portions 1d have been generated. 4 is pressed by a rectangular forming device 40 to form the rectangular wire material 1 into a rectangular cross-section. In this embodiment, the rectangular forming device 40 used here includes a pair of rolling machines that sandwich and press a pair of flat surface portions 1a, 1a on the long sides of the rectangular wire material 1, as shown in FIG. It has rolls 41, 41 and a pair of rolling rolls 42, 42 that sandwich and press a pair of flat surface portions 1b, 1b, which are the short sides of the rectangular wire material 1. In this case, the two sets of rolling rolls 41 and 42 correspond to the second pressing section according to the present invention.

Here, the pressing surfaces 41a and 42a of the respective rolling rolls 41 and 42 both have a cylindrical shape with a constant outer diameter dimension, and are set larger than the width direction dimension or thickness direction dimension of the corresponding flat surface portions 1a and 1b. . Further, the rotation axes X3 and X4 of the respective rolling rolls 41 and 42 are set to be parallel to the width direction or thickness direction of the corresponding flat surface portions 1a and 1b, respectively. The distance between the mutually parallel rotation axes X3, X3 and the distance between the rotation axes X4, X4 are kept constant.

The rectangular forming step S2 using the rectangular forming apparatus 40 having the above configuration is performed, for example, as follows. That is, as shown in FIGS. 2 and 5, the rectangular wire material 1 that has been plastically worked by the protruding deformation device 30 is supplied between each set of rolling rolls 41 and 42, which is the processing area of the rectangular shape forming device 40. At the same time, each set of rolling rolls 41, 42 is rotated around predetermined rotation axes X3, X4. As a result, the rectangular wire material 1 is rolled by each set of rolling rolls 41 and 42 while moving in a predetermined direction. Here, the distance D1 between the set of rolling rolls 41 located on the long side is smaller than the thickness direction dimension T1 of the rectangular wire material 1 including the protruding deformed portion 1d. Further, the distance D2 between the set of rolling rolls 42 located on the short side is smaller than the widthwise dimension W1 of the rectangular wire material 1 including the protruding deformed portion 1d. From the above dimensional relationship, each protruding deformed portion 1d of the rectangular wire material 1 supplied between each set of rolling rolls 41, 42 is crushed by the rolling rolls 41, 42, and the pressing force of each rolling roll 41, 42 is It flows in a direction that fills the empty space 43 between the area defined by the surfaces 41a and 42a and the outer circumferential surface 4 of the rectangular wire material 1 (the portion shown by the two-dot chain line in FIG. 5). As a result, flat surface portions 1a and 1b having a shape that follows the area defined by the pressing surfaces 41a and 42a described above are re-molded on the outer periphery of the flat wire material 1, and the corners between the flat surface portions 1a and 1b are reshaped. The portion 1c is formed to have an acute angle (acute corner portion 1e). As described above, a rectangular wire 1' having a shape in which four flat surface parts 1a and 1b and an acute corner part 1e are provided between adjacent flat surface parts 1a and 1b, that is, a desired rectangular cross section, is obtained. It will be done.

As described above, in the method for manufacturing a rectangular wire according to the present invention, first, the outer circumferential surface 4 of the rectangular wire material 1 is pressed from four directions so that the outer circumferential surface 4 protrudes between the four pressed surfaces 4a and 4b. After generating the deformed portion 1d, the rectangular wire material 1 in which the protruding deformed portion 1d was generated is molded into a rectangular cross-section. According to this method, the protruding deformation portion 1d having a sufficient plastic flow allowance is crushed, and an empty space 43 between the outer circumferential surface 4 of the rectangular wire material 1 and the area defined by the pressing surfaces 41a and 42a is crushed. Flows in the direction that satisfies. As a result, a rectangular wire having a cross-sectional shape that follows the area partitioned by the pressing surfaces 41a and 42a, that is, a rectangular wire having four flat surface portions 1a and 1b and an acute corner portion 1e between each of the flat surface portions 1a and 1b. 1' can be molded. In other words, the corner portion 1c can be made acute while maintaining the rectangular cross-sectional shape of the flat wire material 1. In addition, in the protruding deformation process S1, after the rectangular wire material 1 is once protrudingly deformed in four directions, the protruding deformed portion 1d is crushed and flattened, thereby actively promoting plastic flow within the cross section. plastic flow (elongation) in the longitudinal direction can be sufficiently suppressed or prevented as much as possible. Moreover, since the corner portion 1c can be sharpened with high precision by performing plastic working twice, it is possible to suppress an increase in manufacturing cost due to an increase in the number of man-hours. As described above, according to the present invention, it is possible to make the corner portion 1c of the rectangular wire 1' acute at low cost while preventing the insulating coating 3 from cracking due to elongation in the longitudinal direction.

Further, in the present embodiment, in the protruding deformation step S1, the outer circumferential surface 4 of the rectangular wire material 1 is pressed by two pairs of rolling rolls 31 and 32 as the first pressing portion, both of which have pressing surfaces 31a and 32a in a convex drum shape. Since rolling is performed, it is possible to avoid a situation in which excessive load or stress concentration occurs on the conductive wire 2 or the insulating coating 3, and to smoothly generate the protruding deformation portion 1d. Therefore, in the rectangular forming step S2, by rolling the outer circumferential surface 4 of the rectangular wire material 1 with two pairs of rolling rolls 41 and 42, both of which have cylindrical pressing surfaces 41a and 42a with a constant outer diameter, the corner portions are formed. It becomes possible to stably reproduce the acute angle of 1c.

Although one embodiment of the present invention has been described above, the method for manufacturing a rectangular wire according to the present invention may have a configuration other than the above without departing from the spirit thereof.

For example, in the above embodiment, the flat wire material 1 is a round corner portion in which the corner portion 1c exhibits a larger radius of curvature than the flat surface portions 1a and 1b. Although the case where the rectangularization step) is applied has been described, the application of the present invention is of course not limited to this. For example, it is also possible to apply the present invention to a coated conducting wire having a perfect circular or elliptical cross section.

Furthermore, in the above embodiment, the present invention is applied to the rectangular wire material 1 in which the conductor 2 is covered with the insulating coating 3, but of course the present invention is not applicable to the conductor 2 alone. It is also possible to do so. Since the cost required for processing the conducting wire 2 into a rectangular shape is reduced, even if the cost required for the process of forming the insulating coating 3 is taken into account, it is only necessary to reduce the total cost.

1 Flat wire material 1' Flat wire 1a, 1b Flat surface portion 1c Corner portion 1d Protruding deformation portion 1e Acute corner portion 2 Conductive wire 3 Insulating coating 4 Outer peripheral surfaces 4a, 4b Pressed surface 10 Cross-sectional rectangular device 20 Conveying device 21 Pull-out drum 22 Winding drum 30 Protruding deformation devices 31, 32 Rolling roll (first pressing part)
31a, 32a Pressing surface 40 Rectangular forming device 41, 42 Roll roll (second pressing part)
41a, 42a Pressing surface 43 Space D1, D2 Distance between rolling rolls S1 Projection deformation process S2 Rectangular forming process T1 Thickness direction dimension W1 Width direction dimension X1, X2 Rotation axis X3, X4 Rotation axis

Claims (3)

A step of rectangulating the cross section of a rectangular wire material having four flat surface portions provided on the outer periphery and four corner portions provided between the flat surface portions adjacent to each other; In a method for manufacturing a rectangular wire that obtains a rectangular wire,
In the step of forming the rectangular cross section, the four flat surface portions of the rectangular wire material are pressed from four directions by a first pressing section while moving the rectangular wire material relatively in its longitudinal direction, so as to direct the rectangular wire material toward the four corner portions. a protruding deformation step of causing each corner portion to protrude outward from the flat surface portion before pressing by causing plastic flow;
The outer circumferential surface of the rectangular wire material that has undergone the protruding deformation is pressed from four directions by a second pressing portion having a pressing surface shape different from that of the first pressing portion, thereby forming the rectangular wire material into a rectangular cross-section. 1. A method for manufacturing a flat wire, comprising a rectangular forming step. In the protruding deformation step, the four flat surface parts are rolled by two pairs of rolls serving as the first pressing part, each of which has a convex pressing surface in the shape of a convex drum, to cause protruding deformation in the four corner parts , and ,
In the rectangular forming step, the outer circumferential surface of the rectangular wire material is rolled by two pairs of rolls serving as the second pressing section, each of which has a cylindrical pressing surface with a constant outer diameter, to form the rectangular wire material. 2. The method for manufacturing a flat wire according to claim 1, wherein the wire is formed into a rectangular cross-section. The method for manufacturing a rectangular wire according to claim 1 or 2, wherein in the protrusion deformation step, each corner portion is subjected to bulge deformation so as to protrude outward from any of the flat surface portions and have a convex curved cross section. .

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