JPH07153327A - Litz wire and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve the uniformity and stability of the shape of a litz wire and improve the high frequency transmitting property of the wire without thickening the litz wire. CONSTITUTION:An axial part 2 made of an insulator is used. The diameter of the axial part 2 is smaller than the diameter of the inscribed circle which is formed by arranging bundles 3 of nine elemental wires which are not yet stranded along the circumference of the part. At the time of manufacture, the bundles 3 of nine elemental wires are twisted and pushed in the circumference of the supporting part 20 which is linear and has the same diameter as that of the inscribed circle. At the spindle- shaped tip part of a supporting part 20, the elemental wire bundles 3 are twisted and throttled and thus the inner diameter of the elemental wire bundles 3 becomes narrower gradually. Each elemental wire bundle 3 is twisted and inserted into the outer circumference of the axial part 2 which comes out of an insertion hole 22 in the axial center of the supporting part 20. Then, a string-like sheath material 4 is coiled transversely on the outer circumference of the group of the elemental wire twisted bundles 3. As a result, each elemental wire bundle 3 has a mutually congruent fan-shaped cross section for dividing a circle uniformly. Consequently, an axial part 2 with a small diameter can be used and the litz wire 1 can be thin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a litz wire for high frequency propagation.

[0002]

2. Description of the Related Art In high frequency propagation, due to the skin effect, more current flows toward the outer periphery of the conductor cross section, and conversely the current decreases toward the center of the conductor cross section. In order to reduce such a skin effect, a plurality of individually insulated wire strands are twisted together, or a plurality of wire bundles formed by braiding are further twisted or braided, and then, for example, on the outer periphery of the wire bundle group. A litz wire with a horizontal sheath is used. In such a litz wire, it is desirable to suppress the skin effect by twisting or braiding so that the individual strands of the wire cross over the center and the outer periphery as evenly as possible. Furthermore, the final cross-sectional shape of the litz wire is a perfect circle, and the cross-sectional shape of the segment composed of individual wire bundles is a fan shape that is evenly divided with respect to the axial center of the entire litz wire. It is desirable to have a uniform shape from the center.

However, in the case of twisting a plurality of strands of wire, in order to increase the roundness of the final cross-sectional shape of the whole, for example, 7 concentric twists with the center one as an axis are stabilized. There is. However, with such a concentric twisted litz wire,
Since one central wire bundle does not cross-spread with another wire bundle, it becomes shorter than other wire bundles. As a result, the single filament bundle at the center has a low resistance value in the direct current or low frequency region, and has a higher resistance value in the high frequency region than other strands due to the proximity effect from other strands.

In order to solve such a problem and improve the high-frequency propagation characteristics, for example, as described in Japanese Patent Publication No. 4-25644, a shaft member having a circular cross-section made of an insulator is arranged at the center. , A structure in which a plurality of wire bundles are twisted around the outer circumference thereof has been proposed. With this structure, the individual wire bundles can be positioned fairly symmetrically and evenly about the shaft member.
Then, the current density distribution becomes uniform and the loss resistance due to the skin effect decreases. However, conventionally, a shaft member having substantially the same diameter as the inscribed circle of a plurality of wire bundles arranged in contact with each other along one circumference (the inscribed circle of the original wire bundle group) is used. As the number of wire bundles increases, the skin effect decreases in proportion to the increase in the number of wire bundles, and high-frequency propagation characteristics improve, but on the other hand, the outer diameter of the shaft member also increases,
Therefore, the litz wire in the completed state has an outer diameter increased by the thickness of the shaft member, and the space factor is increased, resulting in an increase in the volume of electronic equipment such as a transformer in which the litz wire is used.

Further, conventionally, the twisting step of twisting the wire bundle and the sheathing step of winding the sheath material around the outer circumference of the twisted wire bundle group have been performed separately. That is, when the twisting process is completed, the group of wire bundles is once wound around a bobbin and then rewound to perform the sheathing process. However, in this conventional method, with winding and unwinding between both steps, the twisted wires or wire bundles are individually bent to enter the center side or bulge outward, or , The bundle of wires is crushed, and the uniform division of each segment cannot be obtained. As a result, the load ratio differs for each wire bundle, and the high frequency propagation characteristics deteriorate.

[0006]

As described above, in a conventional litz wire in which a plurality of wire bundles are twisted around a shaft member made of an insulator, the shaft member is finally in its original shape. Since it remains, the outer diameter becomes large, and there is a problem that the volume of the electronic device in which the litz wire is used increases. On the other hand, the conventional litz wire in which only the conductor wire bundles are twisted together has a problem that it is difficult to evenly distribute the wire bundles and the high-frequency propagation characteristics are poor. Further, in the conventional production of the litz wire, since the twisting process and the sheathing process are separate, there is a problem that the shape and position of the wire bundle are disturbed, and the high frequency propagation characteristic is deteriorated.

The present invention is intended to solve such a problem, and an object of the present invention is to provide a litz wire which has good high frequency propagation characteristics and can be made thin.

[0008]

SUMMARY OF THE INVENTION The present invention is intended to achieve the above object. According to the invention of claim 1, a plurality of element wire bundles are provided around a flexible shaft member made of an insulator. In the litz wire formed by concentrically twisting and sheathing the outer circumference of the twisted wire bundle group, the shaft member has a cross-sectional area smaller than the cross-sectional area of the inscribed circle of the wire bundle group, and The wire bundle has a circular cross section as a whole, in which fan-shapes that are radially divided at substantially equal intervals around the shaft member are closely combined to have a circular cross section.

Further, the invention of claim 2 is a group of wire bundles obtained by twisting or knitting a plurality of wire bundles around a flexible shaft member made of an insulator, and then twisting or knitting the wire bundles. In the method for manufacturing a litz wire in which the outer periphery of the wire is sheathed, the shaft member is linearly extended from the through hole of the support member, and the wire bundles are twisted or braided on the surface of the support member, and then the support is performed. According to the taper of the tip of the member, the twisting diameter or the braiding diameter is reduced, and the twisting or braiding is further performed on the surface of the shaft member. Further, after each wire bundle has passed the tip of the support member, a sheath material is wound around the outer circumference of the wire bundle group in a state where the shaft member is in a straight line coaxial with the support member to perform sheath processing. is there.

According to a third aspect of the present invention, each wire bundle comes into contact with the support member and starts twisting from a portion of the support member having a diameter substantially the same as the inscribed circle of the wire bundle group.

According to a fourth aspect of the present invention, the shaft member has a cross-sectional area smaller than the cross-sectional area of the inscribed circle of the wire bundle group or a cross-sectional area smaller than the cross-sectional area of the inscribed circle. In addition, a shaft member having a circular cross-sectional shape or a shaft member having the same number of corners or folds as a plurality of wire bundles is used.

[0012]

According to the first aspect of the invention, the wire bundles are twisted around a shaft member having a smaller cross-sectional area than the inscribed circle of the wire bundle group, and the sheath material is wound around the outer circumference. As a result, the thickness of the flexible shaft member can be used with the minimum thickness required for twisting, which contributes to space saving of the final product such as a transformer. Or conversely, it is also possible to use a shaft member with an appropriate thickness calculated from the final outer diameter of the litz wire that matches the winding space given to the litz wire by a transformer, etc. Does not need to be thinner than necessary. If the litz wire is made thicker, the skin effect can be reduced accordingly. Of course, it is a shape in which the shaft member is twisted around the center, the twisting of each wire bundle is stable, the individual segments consisting of these wire bundles form a fan shape that is almost evenly divided, and the collapse of each segment It is also very effective in reducing the skin effect because floating lines and slack lines can be greatly reduced.

According to the second aspect of the present invention, while the shaft member is paid out by the support member having the through hole, the strands of wire are started to be twisted from the surface of the support member to the first end of the tapered support member. Tighten the next twist. During the first twisting, each wire bundle undergoes a slight shape change and approaches a fan-shaped cross-sectional shape. Then, the individual wire bundles are twisted around the outer periphery of the shaft member that is fed out from the through hole of the support member. Furthermore, by performing the horizontal winding process of the sheath member in a straight line continuously with the supporting member, each wire and wire bundle do not have the relaxation that occurs when the twisting process and the sheathing process are completely divided, In addition to being subjected to winding tightening with an appropriate horizontal winding tension, inconveniences such as segment shape deformation and crushing do not occur. As a result, unlike the conventional technology, the final cross-sectional shape of the litz wire can easily obtain an arbitrary outer diameter with good reproducibility that is proportional to the thickness of the support member, and it is consistent from twisting to sheathing. The shape of each segment becomes a fan shape that is almost evenly divided,
The strands of wire are uniformly sown at the center of each axis and the outer periphery, so that a litz wire having excellent high frequency propagation characteristics can be realized. The same applies when braiding instead of twisting a plurality of wire bundles.

According to the third aspect of the present invention, the thickness of the supporting member appropriate for stabilizing the stranded wire is defined, and the optimum thickness at which each wire bundle starts to contact the outer periphery of the supporting member is inscribed in the wire bundle group. Matching the diameter of the circle has the effect of forcing the spacing of the array of filament bundles to be even.

According to the fourth aspect of the invention, the effective outer dimensions of the shaft member are defined. The cross-sectional shape of the shaft member is not specified in particular, and from a practical point of view, when the outer shape of the stranded wire is thin, a round shaft member is preferable, and as it becomes thicker, the number of wire bundles is the same as the number of wire bundles. If the shaft member having corners arranged at an angle becomes thicker, a shaft member having a similar fold can be used. When the shaft member having corners or folds is used, the wire bundle that has passed through the tip of the support member is arranged along the corners or folds of the shaft member that has come out from the through hole of the support member. , Each segment is equally divided. This improvement in the even division accuracy leads to an improvement in the high frequency propagation characteristic.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, 1 is a litz wire, 2 is a shaft member having a circular cross-sectional shape, 3 is a wire bundle, 4
Is a sheath material. The shaft member 2 is an insulator and is made of a material having sufficient flexibility. This material is
Although it is a Tetoron synthetic fiber yarn twisted into a thread shape, a monofilament of synthetic resin such as nylon having excellent flexibility is also used. Moreover, although the strand bundle 3 is formed by twisting several strands formed by twisting multiple strands of polyurethane copper wires, it may be a braided wire.
In addition, although the wire bundle before twisting is not coarsely twisted and the wires are not in close contact with each other, the diameter of the shaft member 2 is such that the plurality of wire bundles 3 before twisting are in contact with each other along one circumference. It is smaller than the diameter of the inscribed circle when arranged (the initial inner diameter of the wire bundle group).

In the production of the present litz wire 1,
Nine element wire bundles 3 having substantially the same diameter are concentrically twisted around the shaft member 2 (twisting process step), and then the thread-like sheath material 4 is horizontally wound around the outer circumference of the twisted element wire bundle 3 group. Processing step). The cross-sectional shape of each wire bundle 3 becomes substantially fan-shaped by the horizontal winding tightening applied during the sheath processing. That is, in the manufactured litz wire 1, the cross-sectional shape of each wire bundle 3 is a fan shape which is congruent and divides the circle evenly, and each wire bundle 3 has a shaft member 2.
It is closely combined with and has a circular cross section as a whole.

Next, an apparatus for manufacturing the litz wire 1 will be described with reference to FIGS. 2 and 3. This manufacturing apparatus is provided with a shaft member supply bobbin 10 for feeding the wound shaft member 2.
A twisting mechanism portion 11 for twisting nine strands of wire 3 around the shaft member 2, a sheathing mechanism portion 12 for performing sheathing on the outer periphery of the twisted strands of wire bundle 3, and a sheathing treatment. The Litz wire 1 and the winding unit 13 are provided. These shaft member supply section 10, twisting mechanism section 11, and sheath processing mechanism section
The winding unit 12 and the winding unit 13 are arranged side by side in series. The twisting mechanism 11 has a twisting die 16 that rotates in the direction indicated by arrow A, and a circular through hole 17 is formed in the center of the die 16. Further, on the back surface of the twisting die 16, there are nine feeding bobbins serving as a wire bundle supplying section.
The twisting dies 16 are rotatably arranged side by side at equal intervals on the circumference centered on the through hole 17 of the twisting die 16. Each of these feeding bobbins 18 winds a single wire bundle 3, and feeds these wire bundles 3 toward the through hole 17. Further, a slender columnar support member 20 is fixed to the twisting die 16 via a frame 19. The support member 20 is positioned coaxially with the center axis of the twisting die 16, that is, the rotation axis, and penetrates the through hole 17 coaxially. The tip end 21 of the support member 20 has a spindle shape. Further, a through hole 22 is formed at the axial center of the support member 20. The through hole 22 has a circular cross section and a diameter slightly larger than that of the shaft member 2. Also,
The outer diameter of the support member 20 excluding the tip portion 21 is 9 before being twisted.
It is about the diameter of the inscribed circle of the bundle of strands of a book. Further, the sheath winding mechanism section 12 has a sheathing die 26 which is positioned in parallel with the front of the twisting die 16. This sheath die
26 rotates in the direction indicated by arrow B, that is, in the direction opposite to the twisting die 16 about the same rotation axis as the twisting die 16. The back surface of the sheath die 26 is located slightly forward of the tip of the support member 20. Further, a through hole 27 is formed at the center of the sheath die 26. And on the back of the sheath die 26,
A pair of feeding bobbins 28 are rotatably provided at symmetrical positions with the center of the sheath die 26 in between. Each of these feeding bobbins 28 is wound with one sheath material 4, and these sheath materials 4 are fed toward the through hole 27. Further, the winding section 13 has a winding bobbin 31. The winding bobbin 31 rotates in a direction indicated by an arrow C, and its rotation axis has a directionality substantially orthogonal to the rotation axes of the dies 16 and 26.

Next, a method of manufacturing the litz wire 1 using this apparatus will be described. The tension applied from the rotating winding bobbin 31 causes the shaft member supply bobbin 10 to move to the shaft member 2.
Is paid out. The shaft member 2 linearly passes through the through hole 22 of the support member 20. At the same time, the wire bundle 3 is delivered from each delivery bobbin 18 in the twisting die 16. These wire bundles 3 are radially gathered toward the center of the twisting die 16, surround the support member 20 through the through holes 17, and are drawn toward the tip 21 of the support member 20. Then, the twisting die 16 and the supporting member 20
Are rotating integrally with each other, but by this rotation, the nine wire bundles 3 begin to be twisted in the first stage while being evenly distributed about the support member 20 and along the axial direction thereof. This twisting starts at a position on the outer periphery of the supporting member 20 rearward of the front end portion 21, that is, a position where the outer diameter of the supporting member 20 is about the diameter of the inscribed circle of the original group 3 of wire bundles. . Further, since the tip portion 21 of the support member 20 has a spindle shape, the wire bundle 3 is crushed along the outer periphery of the tip portion 21 and is mildly deformed into a fan shape in cross section. While doing so, the inner diameter of the entire group of the wire bundles 3 gradually decreases to almost the diameter of the shaft member 2. In this second stage in which the axial tightening force is generated, the wire bundle 3 passes through the tip of the supporting member 20 and then also passes through the through hole 22.
It is twisted while maintaining the arrangement state on the outer periphery of the shaft member 2 which has been fed from the tip of the support member 20 through the (twisting process). Immediately after that, the sheath material 4 is horizontally wound around the outer circumference of the group of strands 3 in the sheath processing mechanism 12. That is, with the rotation of the sheath die 26, the sheath material 4 is delivered from the pair of delivery bobbins 28 in the sheath die 26 and wound around the group of wire bundles 3 (sheath processing step). This sheathing is performed by the shaft member 2 and the wire bundle 3.
This is done with the group being in a straight line coaxial with the support member 20. Then, the litz wire 6 is wound around the winding bobbin 31. When the litz wire 6 having a predetermined length is wound around the winding bobbin 31, the winding bobbin around which the litz wire 6 is wound.
Remove 31 from the device. In this way, a series of processes from the beginning of twisting to the sheath processing is continuously performed on the straight running line.

As described above, in the twisting process, the wire bundle 3 is guided on the outer periphery and the supporting member 20 through which the shaft member 2 passes through the through hole 22 at the center of the shaft is used. Will be forced to be placed. Further, since the tip portion 21 of the support member 20 has a spindle shape,
After the first-stage twisting of the wire bundle 3 on the outer circumference of the support member 20, the wire bundle 3 becomes thinner and twists while being in contact with the outer circumference of the shaft member 2 so that the inner diameter of the group of wire bundles 3 is smaller than the initial inner diameter. Even if the thin shaft member 2 is used, stable twisting can be obtained. Moreover, since the portion of the supporting member 20 at which the twisting of the wire bundles 3 is started has almost the same diameter as the diameter of the inscribed circle of the group of the wire bundles 3 at the beginning, it is possible to surely arrange the wire bundles 3 at equal intervals. It can be forced to, and the stranded wire can be stabilized. From these things, the diameter of the shaft member 2 which has been required to have a large diameter as the number of twists increases can be reduced. Therefore, the diameter of the litz wire 1 can be reduced. This is advantageous as the number of twists increases. Since the diameter of the litz wire 1 can be reduced, the space factor thereof can be reduced, which can contribute to space saving of the final product such as a transformer. In addition, due to the stable twisting, individual wire bundles 3
Make sure that the cross-sectional shape of the segment composed of
It becomes a fan shape that is radially evenly divided from the center of the whole axis. Therefore, the individual strands or bundles of strands 3 are alternately seeded around the center and the outer periphery of the litz wire 1, the skin effect is suppressed, and the high frequency propagation characteristics are improved. Of course, because there is no wire bundle that penetrates the center of the litz wire 1,
The proximity effect is also suppressed.

Further, by performing the twisting process and the sheathing process in series, this occurs when the twisting process and the sheathing process are completely divided as in the conventional case.
It is possible to eliminate the variation in the current load ratio caused by the collapse of the shape of the wire bundle 3, that is, the segment, the looseness of the wire and the wire bundle 3, and the bracing. That is, it is possible to prevent the deterioration of the high frequency propagation characteristics due to the skin effect.

Although the nine wire bundles 3 are twisted in the first embodiment, the number of wire bundles to be twisted is not limited to that. In particular, when the number of wire bundles is small, such as six, a shaft member having a diameter equal to the inner diameter of the original wire bundle group may be used.

Then, as described above, the thin shaft member 2 can be used and the litz wire 1 can be thinned by twisting the support member 20 having the spindle-shaped tip portion 21. It is not necessary to make the litz wire thin. That is, it is of course possible to use a shaft member having an appropriate thickness calculated from the final outer diameter of the litz wire that matches the winding space given to the litz wire in a transformer or the like. As the litz wire can be made thicker, its skin effect can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIGS. 4 to 7. It should be noted that description of items common to the first embodiment will be omitted. In the second embodiment, the shaft member 36 has six thin folds 37. These folds 37 are in the form of a continuous flat plate parallel to the axis center of the entire shaft member 36, and are radially arranged at equal intervals with respect to the axis center. That is, the cross-sectional shape is a regular hexagonal diagonal line. Although the material of the shaft member 36 is polyethylene, polypropylene,
Various thermoplastic resins or thermosetting resins such as urethane rubber or polyethylene terephthalate are used.

In the production of the litz wire 1,
Six strands of wire 3 having substantially the same diameter are concentrically twisted around the shaft member 36, and then a filamentous sheath material 4 is wound around the outer periphery of the twisted strands of wire bundle 3 group. In the twisting process,
Each wire bundle 3 is twisted between the folds 37 of the shaft member 36. Along with that, the shaft member 36 is twisted by its own flexibility, and each of the folds 37 is spirally formed. Further, due to the pressure applied at the time of sheath processing, each wire bundle 3 is moved to the shaft member 36.
The cross-sectional shape becomes substantially fan-shaped along the fold 37. That is, in the manufactured litz wire 1, the cross-sectional shapes of the individual wire bundles 3 are congruent and substantially fan-shaped to equally divide a circle, and the individual wire bundles 3 are closely combined with the shaft member 36. The overall shape is circular.

The manufacturing apparatus for the litz wire 1 of the second embodiment is
The supporting member supply bobbin 10 is rotatably supported by the frame 41 fixed to the back side of the twisting die 16 as in the first embodiment. Further, the through hole 42 formed in the axial center of the support member 20 fixed to the same frame 41 has a cross-sectional shape almost equal to that of the shaft member 36, and is slightly larger than this. The through hole 42 is a support member.
Although slits 43 are drawn out to the spindle-shaped tip portion 21 of 20, the slits 43 are inclined with respect to the axial direction of the support member 20. The inclination angle is about half of the angle formed by the wire bundle 3 twisted in the completed litz wire 1 with respect to the axial direction.

Next, in the production of the litz wire 1 using this apparatus, the filament bundle 3 is also twisted around the support member 20, and each filament bundle 3 is a spindle-shaped tip portion of the support member 20. In 21, the shaft member that came out of the slit 43
It is twisted between each fold 37 of 36. At this time, each of these folds 37
Are positioned by the slits 43 with respect to the support member 20, so that the wire bundles 3 are reliably guided between the folds 37. In this way, the six wire bundles 3 are twisted around the shaft member 36 while maintaining the array state. As the strands 3 are twisted together, the shaft member 36 is twisted due to its flexibility. At this time, the shaft member 36 is guided by the inclination of the slit 43.
The twisting of 36 and the twisting of the wire bundle 3 can be performed more reliably. Immediately after the above twisting process, the sheath material 4 is horizontally wound around the outer periphery of the group of strands 3 in the sheath processing mechanism section 12.

As described above, by using the shaft member 36 composed of six folds 37 radially arranged at equal intervals and twisting the wire bundles 3 between the folds 37, the wire bundles 3 are forcedly forced. Since the Litz wires 1 are arranged while being divided into segments, the segments formed by the individual wire bundles 3 in the cross-sectional shape of the litz wire 1 are more surely congruent and substantially fan-shaped to equally divide the circle. . Therefore, the individual strands or bundles of strands 3 surely interleave the center portion and the outer periphery of the litz wire 1 alternately and uniformly. This surely suppresses the skin effect and improves the high-frequency propagation characteristics. Of course, the proximity effect is also suppressed because there is no wire bundle that penetrates the center of the litz wire 1. Also, the shaft member 2
Since it is thin and is located at the boundary between the segments, the diameter of the litz wire 1 does not increase and the space factor can be reduced.

In the second embodiment, the shaft member 36 is twisted in a spiral shape in accordance with the twisting of the wire bundle 3. However, the shaft member has a spiral fold from the beginning. Can also be used. Further, the same applies to the manufacturing apparatus of the first embodiment, but the tip end portion of the support member may have a spindle shape as well as a linear taper shape. However, the spindle shape is more effective. Also, the number of strands of wire to be twisted together is not limited to six.

Further, although the shaft member 36 having the folds 37 is used in the second embodiment, a shaft member having an angle, for example, a shaft member having a regular hexagonal cross section may be used. Generally, when the outer diameter of the stranded wire is small, the round shaft member as in the first embodiment is preferable, and as it becomes thicker, the shaft member has corners arranged at equal angles to the number of wire bundles. However, if it becomes thicker, a shaft member having a similar fold as in the second embodiment can be used. Further, in both of the above-described embodiments, the case where the wire bundles 3 are twisted together has been described, but a plurality of wire bundles may be knitted by ajiro knitting or the like, and sheath processing may be performed. Even in the case of braiding, the same effect can be obtained by using the shaft member and the supporting member as described above.

[0031]

According to the first aspect of the invention, in a litz wire in which a plurality of wire bundles are concentrically twisted around the shaft member and a sheath is applied to the outer circumference of the wire member, the shaft member is made of a wire bundle group. Since the cross-sectional area is smaller than the cross-sectional area of the inscribed circle, the litz wire can be made thinner, and therefore the space factor can be reduced, which contributes to space saving of the final product such as a transformer. In addition, the cross-sectional shape of each wire bundle is a fan shape that is congruent with each other and divides the circle evenly, and each wire bundle is closely combined with the shaft member to form a circular cross section as a whole. Moreover, the individual wire bundles or wires are alternately and evenly seeded around the center and the outer circumference of the litz wire, so that the high frequency propagation characteristics are surely improved.

According to the second aspect of the present invention, a supporting member having a straight through hole at the center of the shaft and a tapered tip is used, and the shaft member is straight from the through hole of the supporting member. The filament bundle is twisted or braided onto the outer periphery of the shaft member while guiding the filament bundles toward the tip along the outer periphery of the support member, so that the filament bundle group can be reliably Since the shaft member can be positioned at the center of the wire and the wire bundle is gradually tightened at the tip of the support member, it is stable even if the shaft member has a cross-sectional area smaller than that of the inscribed circle of the wire bundle group. The twisted or braided wire can be obtained, and the subsequent sheathing can make the cross-sectional shape of each wire bundle into a substantially concentric fan shape that evenly divides a circle. Moreover, since the steps of twisting or braiding and the step of horizontally winding the sheath material are continuously performed with respect to the straight running line, the wire or the wire bundle, which is generated when the both steps are completely divided, is performed. It is possible to prevent loosening, bracing, deformation of the segment shape, crushing, etc., and to improve the high-frequency propagation characteristics more reliably.

Further, according to the invention of claim 3, the twisting of the wire bundles is started from a portion where the outer diameter of the support member is substantially the same as the inscribed circle of the wire bundle group, so that the twisting of the wire bundles is started. The arrangement of the wire bundles can be reliably forced to be evenly spaced, and the stranded wire can be further stabilized.

Further, according to the invention of claim 4, by appropriately adjusting the thickness and shape of the shaft member, a plurality of wire bundles can be bundled under the condition concerning the thickness of the Litz wire to be manufactured. The array of can be more reliably and evenly distributed. For example,
Use a shaft member that has as many corners or folds as the number of wire bundles, and each corner or fold is radially arranged at equal intervals with respect to the axial center and is continuous in the longitudinal direction. By twisting the individual wire bundles, these wire bundles can be reliably and evenly arranged, the accuracy of uniform division of each segment can be further improved, and the high frequency propagation characteristics can be further improved.

[Brief description of drawings]

1A and 1B show a first embodiment of the present invention, in which FIG. 1A is before passing through a support member for a wire bundle, FIG. 1B is before sheathing, and FIG.
Shows the litz wire after sheathing.

FIG. 2 is a perspective view of the above manufacturing apparatus.

FIG. 3 is an enlarged cross-sectional view of a part of the above manufacturing apparatus.

FIG. 4 is a sectional view showing a second embodiment of the present invention,
(A) shows the litz wire before sheathing, and (b) shows the litz wire after sheathing.

FIG. 5 is a perspective view of the above manufacturing apparatus.

FIG. 6 is an enlarged cross-sectional view of a part of the above manufacturing apparatus.

FIG. 7 is a perspective view of the same support member and shaft member.

[Explanation of Codes] 1 Litz wire 2 Shaft member 3 Element bundle 4 Sheath material 20 Support member 21 Tip 22 Through hole 36 Shaft member 37 Fold 42 Through hole

Claims (4)

[Claims] 1. A plurality of element wire bundles are concentrically twisted around a flexible shaft member made of an insulator,
In the litz wire in which the outer circumference of the twisted wire bundle group is sheathed, the shaft member has a cross-sectional area smaller than the cross-sectional area of the inscribed circle of the wire bundle group, and the cross section of each wire bundle. A litz wire characterized in that the shape is a fan shape that is congruent to divide a circle into equal parts, and that the wire bundles are closely combined with the shaft member to have a circular cross section as a whole. 2. A plurality of element wire bundles are twisted or knitted around a flexible shaft member made of an insulator, and then a sheath is formed on the outer circumference of the twisted or knitted element wire bundle group. In the method for manufacturing a litz wire to be applied, the shaft member is linearly fed from a through hole of a support member having a tapered tip with a slightly larger through hole that is similar to the shape of the shaft member, A step of twisting or braiding these plural wire bundles on the outer periphery of the shaft member while guiding the plural wire bundles toward the tip along the outer circumference of the support member, and the twisted or knitted element A method for manufacturing a litz wire, comprising a step of winding a sheath material around an outer circumference of a wire bundle group, and performing the both steps continuously on a straight running line. 3. The litz wire according to claim 2, wherein the twisting of the wire bundle is started from a portion where the outer diameter of the support member is substantially the same as the inscribed circle of the wire bundle group. Production method. 4. The shaft member uses a shaft member having a cross-sectional area smaller than an outer diameter of the support member or smaller than a cross-sectional area of an inscribed circle of the wire bundle group, and the shaft member has a round cross section. Or having as many corners or folds as the number of a plurality of wire bundles, and each corner or fold is radially located at equal intervals with respect to the axial center and is continuous in the longitudinal direction. The method for manufacturing a litz wire according to claim 2.