CN110622260A

CN110622260A - Anti-surge winding low-temperature fusing resistor and manufacturing method thereof

Info

Publication number: CN110622260A
Application number: CN201780088781.6A
Authority: CN
Inventors: 李尚祐
Original assignee: Lee Shang Yo
Current assignee: Lee Shang Yo
Priority date: 2017-06-29
Filing date: 2017-06-29
Publication date: 2019-12-27
Anticipated expiration: 2037-06-29
Also published as: EP3646354A1; KR20200024258A; CN110622260B; JP6836669B2; JP2020526042A; EP3646354A4; WO2019000306A1; CN110622260B8

Abstract

A fuse resistor includes an insulating rod, a first winding wire, a second winding wire, and a connecting wire. The insulating rod has a first end and a second end. The first winding wire is wound around the insulating rod from the first end, and one end of the first winding wire is electrically welded to the first cap. The second winding wire is wound around the insulating rod from the second end, and one end of the second winding wire is electrically welded to the second cap. The connecting wire is arranged between the first winding and the second winding, wherein the melting point of the connecting wire is lower than that of the first winding and the second winding, and the first winding and the second winding are separated from each other and are electrically connected through the connecting wire. The fuse resistor further includes a first electrical cover layer electrically connecting one end of the first winding to the first cap; and a second electric covering layer electrically connecting one end of the second winding to the second cap to strengthen and fix the first winding and the second winding to increase the anti-surge effect.

Description

Anti-surge winding low-temperature fusing resistor and manufacturing method thereof

Technical Field

The present disclosure relates to a fuse resistor and a method for manufacturing the same, and more particularly, to a surge-resistant winding low-temperature fuse resistor and a method for manufacturing the same.

Background

The fuse resistor can play a role of a fixed resistor when the circuit normally works, and when the working current of the fuse resistor exceeds the rated current, the fusing temperature of the fuse resistor is that the fuse resistor will be fused like a fuse due to overheating so as to protect the circuit. Generally, the fusing temperature of a wire-wound fuse resistor is the melting point of its wire. However, because of the resistance and other electrical considerations, the wire material of the conventional fuse resistor is mainly made of high melting point alloy, and the fuse temperature is too high, which causes a red process, which may burn other components of the circuit, thereby affecting the circuit protection effect.

Disclosure of Invention

One objective of the present disclosure is to provide an anti-surge winding low-temperature fuse resistor.

The embodiment of the disclosure provides a fuse resistor, which includes an insulating rod, a first winding, a second winding, and a connecting wire. The insulating rod has a first end and a second end. The first winding is wound around the insulating rod from a first end of the insulating rod. The second winding is wound around the insulator rod from the second end of the insulator rod. The connecting wire is arranged between the first winding and the second winding, wherein the melting point of the connecting wire is lower than that of the first winding and the second winding, and the first winding and the second winding are separated from each other and are electrically connected through the connecting wire.

According to some embodiments of the present disclosure, the fuse resistor further includes a first insulating layer covering the first winding and the second winding, wherein the first insulating layer has an opening exposing a portion of the insulating rod.

According to some embodiments of the present disclosure, the material of the first insulating layer includes epoxy resin, silicone non-flammable paint, or enamel paint.

According to some embodiments of the present disclosure, the opening includes a slit opening that surrounds the insulating rod and partially exposes the insulating rod.

According to some embodiments of the present disclosure, the opening includes a dot-shaped opening partially exposing the insulating rod.

According to some embodiments of the present disclosure, the connection wire is in contact with the first wire and the second wire through the opening of the first insulating layer.

According to some embodiments of the present disclosure, the fuse resistor further includes a second insulating layer covering the first insulating layer and the connecting wires and filling the opening of the first insulating layer.

According to some embodiments of the present disclosure, the material of the second insulating layer includes epoxy resin, silicone non-combustible paint, or enamel paint.

According to some embodiments of the present disclosure, the fuse resistor further includes a first cap electrically welded to one end of the first winding from the first end of the insulating rod, and a second cap electrically welded to one end of the second winding from the second end of the insulating rod.

According to some embodiments of the present disclosure, the fuse resistor further includes a first electrical covering layer electrically connecting one end of the first winding to the first cap; and a second electric coating layer electrically connecting one end of the second winding to the second cap.

According to some embodiments of the present disclosure, the material of the first and second electrical covering layers respectively comprises tin, copper, iron, silver, nickel or an alloy thereof.

According to some embodiments of the present disclosure, the first and second electrical cover layers have a thickness of between 1 and 20 microns, respectively.

Another embodiment of the present disclosure provides a method for manufacturing a fuse resistor, including: providing an insulating rod; winding a wire on the insulating rod; cutting the winding to form a first winding and a second winding which are separated from each other; and forming a connection wire to electrically connect the first wire and the second wire, wherein the melting point of the connection wire is lower than the melting point of the first wire and the second wire.

According to some embodiments of the present disclosure, the method of manufacturing a fuse resistor further includes forming a first insulating layer on the insulating rod and the winding before cutting the winding; and forming an opening in the first insulating layer and cutting the winding.

According to some embodiments of the present disclosure, the method of manufacturing a fuse resistor further includes forming a second insulating layer covering the first insulating layer and the connecting wires and filling the second insulating layer into the openings of the first insulating layer.

According to some embodiments of the present disclosure, the method of manufacturing a fuse resistor further includes forming a first cap at a first end of the insulating rod and forming a second cap at a second end of the insulating rod.

According to some embodiments of the present disclosure, the method of manufacturing a fuse resistor further includes electrically welding one end of the winding to the first cap, and electrically welding the other end of the winding to the second cap.

According to some embodiments of the present disclosure, the method of manufacturing a fuse resistor further includes electrically connecting one end of the first winding wire to the first cap using the first electrical covering layer, and electrically connecting one end of the second winding wire to the second cap using the second electrical covering layer.

According to some embodiments of the present disclosure, the first electrical cover layer, the second electrical cover layer and the connecting wires are formed together by the same process.

Drawings

To assist the reader in achieving the best understanding, it is recommended that the present disclosure be read with reference to the accompanying drawings and detailed written description thereof. Please note that the drawings in this patent specification are not necessarily drawn to scale in order to comply with industry standards. In some drawings, the dimensions may be exaggerated or minimized intentionally to assist the reader in understanding the discussion herein.

FIG. 1 shows a fuse resistor according to an embodiment of the present disclosure;

FIGS. 2, 3, 4 and 5 are schematic diagrams illustrating a method of manufacturing a fuse resistor according to an embodiment of the disclosure;

FIG. 6 shows a fuse resistor according to another embodiment of the present disclosure; and

FIGS. 7, 8 and 9 are schematic diagrams illustrating a method of manufacturing a fuse resistor according to another embodiment of the disclosure.

Detailed Description

The present disclosure provides many different implementations or embodiments for implementing different features of the disclosure. For simplicity of illustration, examples of specific components and arrangements are also described in the present disclosure. It should be noted that these specific examples are provided for illustrative purposes only and are not intended to be limiting in any way. For example, the following description of how a first feature may be formed over or on a second feature may include certain embodiments in which the first feature is in direct contact with the second feature, and may also include other embodiments in which the second feature is intermediate to the first feature such that the first feature is not in direct contact with the second feature. Moreover, the various examples in this disclosure may use repeated reference numbers and/or textual labels, which do not represent an association between the various embodiments and configurations, to make the document simpler and clearer.

Furthermore, the present disclosure uses spatially relative terms, such as "under," "lower," "below," "over," "upper," "over," and "above" and similar terms, to describe one element or feature relative to another element(s) or feature(s) as illustrated for ease of description. These spatially relative terms are intended to describe possible angles and orientations of the device in use and operation in addition to the angular orientation shown in the figures. The angular orientation of the device may vary (rotated 90 degrees or at other orientations) and these spatially relative descriptors used in this disclosure are to be interpreted in a similar manner.

Please refer to fig. 1. FIG. 1 shows a fuse resistor according to an embodiment of the present disclosure. As shown in fig. 1, the fuse resistor 1 of the present embodiment includes an insulating rod 10, a first winding wire 22, a second winding wire 24, and a connecting wire 26. The insulated wire 10 has a first end 101 and a second end 102. The insulating rod 10 of the present embodiment may comprise a ceramic rod, but the material is not limited to ceramic material, and any insulating material such as glass fiber may be used for the purpose of the present disclosure. In addition, the insulating rod 10 of the present embodiment has a cylindrical shape, but is not limited thereto.

The first winding 22 is wound around the insulator rod 10 from the first end 101 and the second winding 24 is wound around the insulator rod 10 from the second end 102, wherein the first winding 22 and the second winding 24 are not directly connected with a gap. In some embodiments, the first and second windings 22 and 24 are helically wound around the insulating rod 10. In some embodiments, the gap between the first and second windings 22, 24 is between about 0.05 millimeters (mm) to about 2 mm. The connecting wire 26 is disposed between the first winding 22 and the second winding 24, and the length of the connecting wire 26 may be slightly greater than the gap between the first winding 22 and the second winding 24 to connect the first winding 22 and the second winding 24. The melting point of the connection wire 26 is lower than the melting points of the first and second windings 22 and 24, and the first and second windings 22 and 24 are separated from each other and electrically connected through the connection wire 26.

In the present embodiment, the material of the first winding 22 and the second winding 24 may include or be selected from materials having a melting point higher than that of the connecting wires 26, for example, the melting point of the first winding 22 and the second winding 24 is between about 800 degrees celsius and 1500 degrees celsius, and the melting point of the connecting wires 26 may be lower than about 500 degrees celsius or lower than about 300 degrees celsius, for example, between about 200 degrees celsius and 300 degrees celsius, but not limited thereto. The materials of the first winding 22, the second winding 24 and the connecting wires 26 may be determined according to the electrical specification and safety specification of the resistor. In some embodiments, the material of first winding 22 and second winding 24 may comprise or be selected from a nickel-copper alloy or other suitable high melting point conductive metal or alloy material, while the material of bonding wire 26 may comprise or be selected from tin, copper or other low melting point conductive metal or alloy material. With the above configuration, when the operating current of the fuse resistor 2 of the present embodiment exceeds the rated current, the connecting wires 26 with low melting point have lower fusing temperature and higher fusing speed, and thus will be blown first to protect the circuit. It is also worth noting that under normal operation, the operating temperature of fuse resistor 1 is below about 70 ℃, so that connecting wires 26 having a low melting point do not affect the normal operation of fuse resistor 1.

In some embodiments, the fuse resistor 1 may further include a first insulating layer 12 covering the first winding 22 and the second winding 24. The first insulating layer 12 has an opening 12S exposing a portion of the insulating rod 10. In some embodiments, the material of the first insulating layer 12 may include or be selected from an insulating varnish such as an epoxy or other insulating material. In some embodiments, the connecting wires 26 are in contact with the first and second windings 22 and 24 through the opening 12S of the first insulating layer 12. In some embodiments, the opening 12S of the first insulating layer 12 may include a slit opening that surrounds the insulating rod 10 and partially exposes the insulating rod 10. In some embodiments, the width of the slit opening of the first insulating layer 12 is between about 0.05 mm and about 2 mm, but not limited thereto.

In some embodiments, the fuse resistor 1 may further include a second insulating layer 14 covering the first insulating layer 12 and the connecting layer 26 and filling the opening 12S of the first insulating layer 12. In some embodiments, the material of the second insulating layer 14 may include or be selected from an insulating varnish such as an epoxy, a silicone non-flammable varnish or enamel varnish, or other insulating material.

In some embodiments, the fuse resistor 1 may further include a first cap 32 and a second cap 34. A first cap 32 is capped from the first end 101 of the insulator rod 10 and electrically connected to the first winding 22 and a second cap 34 is capped from the second end 102 of the insulator rod 10 and electrically connected to the second winding 24. In some embodiments, the material of the first and second caps 32, 34 may include iron, steel, aluminum, copper, or other metals, alloys, or graphite materials. In some embodiments, an end of the first winding 22 may be first electrically welded to the first cap 32, and an end of the second winding 24 may be first electrically welded to the second cap 34. In some embodiments, the fuse resistor 1 may further include a first electrical covering layer 361 electrically connecting one end of the first winding 22 to the first cap 32; and a second electrical covering layer 362 electrically connecting one end of the second winding 24 to the second cap 34. In some embodiments, the materials of the first and second electric covering layers 361 and 362 may respectively include tin, copper, iron, silver, nickel or alloys thereof, but are not limited thereto. In some embodiments, the first and second electric covering layers 361 and 362 may be formed by electroplating, for example, but not limited thereto. In some embodiments, the first and second electric covering layers 361, 362 and the connecting conductive line 26 can be formed together by the same process to simplify the process. In some embodiments, the thickness of the first and second electric covering layers 361 and 362 is between about 1 to about 20 micrometers, respectively, but not limited thereto. Since the disconnection of the conventional wire resistor occurs at the solder joint between the wire and the cap with a probability of more than 90% under the surge condition, open circuit failure occurs. Therefore, the first and second electric covers 361 and 362 can be used to reinforce the welding points of the first and second windings 22 and 24, respectively, so as to improve the welding points firmness, reduce the production failure rate, and further improve the reliability of the welding points. The first and second electric covers 361 and 362 can ensure the welding firmness of the first and second windings 22 and 24, thereby improving the anti-surge (anti-surge) effect of the fuse resistor 1.

In some embodiments, the fuse resistor 1 may further include a first conductive wire 42 extending outwardly from the first cap 32 and electrically connected to the first cap 32; and a second lead 44 extending outwardly from the second cap 34 and electrically connected to the second cap 34. The first and second conductive lines 42 and 44 may be electrically connected to an external circuit, such as a printed circuit board.

Please refer to table 1. Table 1 shows the blowing test results of the fuse resistors of the comparative example and the embodiment of the present disclosure.

TABLE 1

Test sample	Specification of resistance value	Fusing power multiplying factor/power	Time of fusion	Fusing temperature
					Fuse resistor of comparative example	2W/1Ω±5％	40 times/80W	15.63s	862.63℃
Fuse resistor of the disclosed embodiment	2W/1Ω±5％	40 times/80W	4.38s	353.31℃

In the blowing test of table 1, the resistance specifications of the fuse resistor of the comparative example and the fuse resistor of the presently disclosed example are both 1 Ω and 2 watts (W), wherein the first and second windings of the fuse resistor of the comparative example are directly connected, and the first and second windings of the fuse resistor of the presently disclosed example are electrically connected via the low melting point connecting wire. For example, the connection wires may be made of tin and formed by electroplating. As shown in table 1, the resistance errors of the fuse resistor of the comparative example and the fuse resistor of the present disclosure are within the tolerance range (± 5%), and the fusing time and the fusing temperature of the fuse resistor of the present disclosure are lower than those of the fuse resistor of the comparative example under the condition that the fusing power ratio is set at 40 times, which proves that the fuse resistor of the present disclosure can effectively enhance the protection effect on the circuit.

Please refer to fig. 2, 3, 4 and 5. FIGS. 2, 3, 4 and 5 are schematic diagrams illustrating a method for manufacturing a fuse resistor according to an embodiment of the disclosure. As shown in fig. 2, an insulating rod 10 is provided. The insulating rod 10 has a first end 101 and a second end 102. Next, the winding wire 21 is wound on the insulating rod 10. In some embodiments, the insulating rod 10 may be formed with a first cap 32 and a second cap 34 on both sides thereof, and the first cap 32 and the second cap 34 may be formed with first and second conductive lines 42 and 44 extending outward on the outer sides thereof, respectively. In some embodiments, the two ends of the wire 21 may be welded to the first cap 32 and the second cap 34, respectively, by electric welding. For example, one end of the winding 21 may be electrically welded to the first cap 32, the winding 21 may be wound on the insulating rod 10, and the other end of the winding 21 may be electrically welded to the second cap 34.

As shown in fig. 3, a first insulating layer 12 is formed on the insulating rod 10 and the winding 21. As shown in fig. 4, an opening 12S is formed in the first insulating layer 12 and the winding 21 is cut to form a first winding 22 and a second winding 24 separated from each other. In some embodiments, the opening 12S of the first insulating layer 12 is a slit opening that surrounds the insulating rod 10 and partially exposes the insulating rod 10. In some embodiments, the steps of forming the slit opening of the first insulating layer 12 and cutting the winding 21 may be performed together. In some embodiments, the steps of forming the slit opening of the first insulating layer 12 and cutting the winding 21 may be performed by using a cutting tool, but not limited thereto. As shown in fig. 5, a connecting wire 26 is formed to electrically connect the first winding 22 with the second winding 24. In some embodiments, the connecting wires 26 may be formed using electroplating, immersion tin baths, or other suitable processes. In some embodiments, to enhance the solder joint integrity between the first winding 22 and the first cap 32 and the solder joint integrity between the second winding 24 and the second cap 34, a first electrical covering 361 can be used to electrically connect (e.g., plate) one end of the first winding 22 to the first cap 32 and a second electrical covering 362 can be used to electrically connect (e.g., plate) one end of the second winding 24 to the second cap 34 to improve solder joint reliability. As shown in fig. 1, a second insulating layer 14 is formed to cover the first insulating layer 12 and the connecting wires 26 and fill the openings 12S of the first insulating layer 12, so as to manufacture the fuse resistor 1 of the present embodiment.

The fuse resistor of the present disclosure is not limited to the above-mentioned embodiments but may have other various embodiments. To simplify the description and facilitate comparison between each of the embodiments of the present disclosure, like components in each of the following embodiments are labeled with like numerals. In order to more easily compare differences between embodiments, the following description will detail differences between different embodiments and will not repeat the same components and their associated details.

Please refer to fig. 6. FIG. 6 shows a fuse resistor according to another embodiment of the present disclosure. As shown in fig. 6, unlike the fuse resistor 1 of fig. 1, the opening 12S of the first insulating layer 12 of the fuse resistor 2 of the present embodiment includes a dot-shaped opening, which partially exposes the insulating rod 10. In some embodiments, the shape of the dotted openings may comprise any regular or irregular geometric shape. In some embodiments, the width or diameter of the dot-shaped opening is between about 0.05 mm and about 2 mm, but not limited thereto. In the present embodiment, the material of the first insulating layer 12 may include or be selected from insulating paint such as epoxy, silicone non-flammable paint or enamel paint, or other insulating materials. The connection wire 26 is in contact with the first and second windings 22 and 24 through the opening 12S of the first insulating layer 12. In addition, the second insulating layer 14 covers the first insulating layer 12 and the connecting layer 26 and fills the opening 12S of the first insulating layer 12. In this embodiment, the material of the second insulating layer 14 may include or be selected from an insulating paint such as epoxy, silicone non-flammable paint or enamel paint, or other insulating materials. The positions, connection modes, materials and other characteristics of the insulating rod 10, the first winding 22, the second winding 24, the connection layer 26, the first cap 32, the second cap 34, the first electric cover layer 361, the second electric cover layer 362, the first conductive line 42 and the second conductive line 44 of the fuse resistor 2 of the present embodiment may be the same as those of the fuse resistor 1 of fig. 1, and are not repeated herein.

Please refer to fig. 7, 8 and 9. FIGS. 7, 8 and 9 are schematic diagrams illustrating a method of manufacturing a fuse resistor according to another embodiment of the disclosure. As shown in fig. 2, an insulating rod 10 is provided. The insulating rod 10 has a first end 101 and a second end 102. Next, the winding wire 21 is wound on the insulating rod 10. In some embodiments, the insulating rod 10 may be formed with a first cap 32 and a second cap 34 on both sides thereof, and the first cap 32 and the second cap 34 may be formed with first and second conductive lines 42 and 44 extending outward on the outer sides thereof, respectively. In some embodiments, the two ends of the wire 21 may be welded to the first cap 32 and the second cap 34, respectively, by electric welding. For example, one end of the winding 21 may be electrically welded to the first cap 32, the winding 21 may be wound on the insulating rod 10, and the other end of the winding 21 may be electrically welded to the second cap 34. Subsequently, the first insulating layer 12 is formed on the insulating rod 10 and the winding 21.

As shown in fig. 8, an opening 12S is formed in the first insulating layer 12 and the winding 21 is cut to form a first winding 22 and a second winding 24 separated from each other. In some embodiments, the opening 12S of the first insulating layer 12 is a dot-shaped opening, which partially exposes the insulating rod 10. In some embodiments, the step of forming the dot-shaped openings of the first insulating layer 12 and the step of cutting the winding 21 may be performed together. In some embodiments, the steps of forming the dot-shaped openings of the first insulating layer 12 and cutting the winding 21 may be performed by using a cutting tool, for example. As shown in fig. 9, a connecting wire 26 is formed in the spot opening to electrically connect the first winding 22 with the second winding 24. In some embodiments, the connecting wires 26 may be formed using electroplating, immersion tin baths, or other suitable processes. In some embodiments, to enhance the solder joint integrity between the first winding 22 and the first cap 32 and the solder joint integrity between the second winding 24 and the second cap 34, a first electrical covering 361 can be used to electrically connect (e.g., plate) one end of the first winding 22 to the first cap 32 and a second electrical covering 362 can be used to electrically connect (e.g., plate) one end of the second winding 24 to the second cap 34 to improve solder joint reliability. As shown in fig. 6, a second insulating layer 14 is formed to cover the first insulating layer 12 and the connecting wires 26 and fill the openings 12S of the first insulating layer 12, so as to manufacture the fuse resistor 2 of the present embodiment.

The fusing resistor disclosed by the invention is electrically connected with the first winding wire and the second winding wire by utilizing the connecting wire, so that the fusing temperature and the fusing speed of the resistor can be controlled, and the application range and the safety of the resistor are further increased. In addition, the fusing resistor disclosed by the invention utilizes the electric covering layer to reinforce the welding spots of the winding and the cap, so that the welding firmness can be increased, the loosening of the winding is avoided, the production failure rate is reduced, and the sudden-wave-resistant welding spot failure rate of the fusing resistor disclosed by the invention is lower than 0.1 ppm. The fuse resistor can improve the surge resistance effect of the fuse resistor, and can be applied to circuits such as surge resistance circuits, spark plug covers of automobiles and motorcycles, ignition systems and the like.

While the present disclosure has been described and illustrated with reference to particular embodiments thereof, such description and illustration are not intended to limit the present disclosure. It will be apparent to those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the true spirit and scope of the disclosure as defined by the appended claims.

Claims

1. A fuse resistor, comprising:

an insulating rod having a first end and a second end;

a first winding wound around the insulating rod from the first end of the insulating rod;

a second winding wound around the insulating rod from the second end of the insulating rod; and

and a connection wire disposed between the first and second windings, wherein a melting point of the connection wire is lower than that of the first and second windings, and the first and second windings are separated from each other and electrically connected via the connection wire.

2. The fuse resistor of claim 1, further comprising a first insulating layer covering the first and second windings, wherein the first insulating layer has an opening exposing a portion of the insulating rod.

3. The fuse resistor of claim 2, wherein a material of the first insulating layer comprises epoxy, silicone non-combustible paint, or enamel paint.

4. The fuse resistor of claim 2, wherein the opening comprises a slit opening that surrounds the insulating rod and partially exposes the insulating rod.

5. The fuse resistor of claim 2, wherein the openings comprise point-like openings that partially expose the insulating rods.

6. The fuse resistor of claim 2, wherein the connection wire is in contact with the first and second winding wires through the opening of the first insulating layer.

7. The fuse resistor of claim 6, further comprising a second insulating layer covering the first insulating layer and the connecting wires and filling the openings of the first insulating layer.

8. The fuse resistor of claim 7, wherein a material of the second insulating layer comprises epoxy, silicone non-combustible paint, or enamel paint.

9. The fuse resistor of claim 1, further comprising a first cap electrically welded from the first end of the insulating rod and to an end of the first wire, and a second cap electrically welded from the second end of the insulating rod and to an end of the second wire.

10. The fuse resistor of claim 9, further comprising a first electrical cover layer electrically connecting an end of the first winding to the first cap, and a second electrical cover layer electrically connecting an end of the second winding to the second cap.

11. The fuse resistor of claim 10, wherein the materials of the first and second electrical cover layers each comprise tin, copper, iron, silver, nickel, or alloys thereof.

12. The fuse resistor of claim 10, wherein the thickness of the first and second electrical cover layers is between 1-20 microns, respectively.

13. A method of manufacturing a fuse resistor, comprising:

providing an insulating rod;

winding a winding on the insulating rod;

cutting the winding wire to form a first winding wire and a second winding wire which are separated from each other; and

forming a connection wire to electrically connect the first wire and the second wire, wherein a melting point of the connection wire is lower than melting points of the first wire and the second wire.

14. The method of manufacturing of claim 13, further comprising:

forming a first insulating layer on the insulating rod and the winding wire before cutting off the winding wire; and

and forming an opening in the first insulating layer and cutting off the winding.

15. The method of manufacturing of claim 14, wherein the opening comprises a slit opening surrounding and partially exposing the insulating rod.

16. The manufacturing method according to claim 14, wherein the opening includes a dot-like opening partially exposing the insulating rod.

17. The method of claim 14, further comprising forming a second insulating layer covering the first insulating layer and the connecting wires and filling the openings of the first insulating layer.

18. The method of claim 13, further comprising capping a first end of the insulating rod with a first cap and capping a second end of the insulating rod with a second cap.

19. The method of manufacturing of claim 18, further comprising electrically welding one end of the wire to the first cap and electrically welding the other end of the wire to the second cap.

20. The method of manufacturing of claim 19, further comprising electrically connecting an end of the first winding to the first cap with a first electrical cover layer, and electrically connecting an end of the second winding to the second cap with a second electrical cover layer.

21. The method of claim 20, wherein the first electrical cladding layer, the second electrical cladding layer and the connecting wire are formed together by a same process.