Wire connector and method for manufacturing the same, sensor element and method for manufacturing the same

Abstract

The electric wire connector (1A) of the present application includes a first electric wire (10A), a second electric wire (20A) electrically connected to the first electric wire (10A), a connecting portion (30) connecting the first electric wire (10A) and the second electric wire (20A), and an insulating cover (13) covering around the connecting portion (30). The connecting portion (30) is formed by butt welding the first electric wire (10A) and the second electric wire (20A).

Description

TECHNICAL FIELD

[0001] The present application relates to an electric wire connection body in which front end faces are connected to each other by butt welding. BACKGROUND

[0002] Examples in which end portions of a pair of electric wires to be separated are connected to each other for use are numerous. Among them, for example, Patent Literature 1 proposes a method of connecting a relay wire connected to an electrode wire of a temperature sensor and a conductive wire composed of a strand of conductive wires by resistance welding. The connection method of Patent Literature 1 includes a first resistance welding and a second resistance welding.

[0003] The first resistance welding is to arrange a pair of welding electrodes in a manner of sandwiching the front end of the conductive wire, flow a current between the welding electrodes, and form a first deposited portion that integrally unifies the conductive wire composed of the respective core wires by fusion bonding.

[0004] The second resistance welding is to connect the conductive wire and the relay wire. Specifically, the conductive wire and the relay wire are arranged in an overlapping manner, and a welding electrode used in the second resistance welding is arranged in a manner of sandwiching the conductive wire and the relay wire at a position on the rear end side from the first deposited portion, and a current is flowed between the welding electrodes to generate Joule heat and weld the core wires and the relay wire. Thus, a second deposited portion is formed.

[0005] After the second resistance welding, Patent Literature 1 moves an auxiliary ring having electrical insulation to electrically seal the first deposited portion and the second deposited portion.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT LITERATURE

[0008] Patent Literature 1: Japanese Patent Application Publication No. 2013-68610 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] In the connection method based on resistance welding of Patent Literature 1, in addition to the work of peeling off the insulating cover of the end portion of the conductive wire before the first resistance welding, the work of moving the auxiliary ring is required. In addition, in the connection method of Patent Literature 1, since the conductive wire and the relay wire are overlapped, the diameter of the connection portion accordingly becomes large.

[0011] Therefore, an object of the present application is to provide an electric wire connection body in which the work of connection based on welding is simple, and the diameter of the welded portion can be controlled. In addition, an object of the present application is to provide a connection method that can obtain such a connection body.

[0012] MEANS FOR SOLVING THE PROBLEMS

[0013] The electric wire connector of the present application has a first electric wire, a second electric wire electrically connected to the first electric wire, a connecting portion connecting the first electric wire and the second electric wire, and an insulating covering covering the connecting portion. The connecting portion connects the first electric wire and the second electric wire by butt welding.

[0014] In the present application, the insulating covering preferably has an inner diameter equivalent to the wire diameter of either of the first electric wire and the second electric wire, and the connecting portion preferably has a wire diameter equivalent to the wire diameter of either of the first electric wire and the second electric wire.

[0015] In the present application, the insulating covering is preferably an insulating covering provided in advance in either of the first electric wire and the second electric wire, or is composed of a hollow insulating body formed separately and having a wire diameter equivalent to that of the insulating covering of the first electric wire and the second electric wire.

[0016] In the present application, the insulating covering is preferably composed of a fluororesin or glass.

[0017] In the present application, the first electric wire preferably has a laser absorption rate of the insulating covering smaller than that of the core wire.

[0018] The present application provides a sensor element having a detection body and a pair of electric wire connectors electrically connected to the detection body. As the electric wire connector, the electric wire connector of the present application is applied.

[0019] The present application provides a manufacturing method of an electric wire connector connecting a first electric wire and a second electric wire by butt welding. The manufacturing method has: a butting process of butting the front end faces of the first electric wire and the second electric wire to each other; and an irradiation process of irradiating laser light to the first electric wire and the second electric wire after butting to form a connecting portion based on welding.

[0020] In the present application, at least before the irradiation process, the region where the connecting portion is formed is covered by the insulating covering.

[0021] The insulating covering of the present application is preferably an insulating covering provided in advance in either of the first electric wire and the second electric wire. In this case, after a pocket forming process of irradiating laser light to the core wire covered by the insulating covering to thereby form a pocket of a gap where the core wire is not present inside the insulating covering, a butting process of butting the front end faces of the first electric wire and the second electric wire to each other is performed in the gap.

[0022] In the pocket forming process of the present application, the gap is preferably formed by volume reduction accompanying melting and solidification of the core wire due to irradiation of laser light to the front end portion of the core wire.

[0023] In the pocket forming step of the present application, it is preferable that the core wire is melted by irradiating laser light to the core wire, and the core wire on the front end side of the melting is removed, thereby forming the void.

[0024] In the present application, it is preferable that the insulating cover is separate from the insulating cover of the first electric wire and the second electric wire. In this case, in the butting step, the stripped core wire of the first electric wire and the stripped core wire of the second electric wire are butted inside the separate insulating cover.

[0025] In the present application, it is preferable that the insulating cover is composed of a jig that is separate from the insulating cover of the first electric wire and the second electric wire and is formed of a material that transmits laser light. In this case, in the butting step, the stripped core wire of the first electric wire and the stripped core wire of the second electric wire are butted inside the jig. Then, in the irradiating step, the laser light transmits the jig and is irradiated to the core wires.

[0026] The present application provides a manufacturing method of a sensor element that electrically connects a pair of electric wire connectors and a detection body. The electric wire connectors are connected to the detection body by the above-described manufacturing method of the electric wire connectors.

[0027] Effects of the Invention

[0028] According to the present application, it is possible to provide an electric wire connector that is simple in connection work based on welding and can suppress the diameter of the welded portion. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a view that shows an electric wire connector of a first embodiment of the present application.

[0030] Figure 2 is a view that shows a manufacturing method of the electric wire connector of Figure 1 the first embodiment.

[0031] Figure 3 is a view that shows the manufacturing method of the first embodiment. Figure 2

[0032] Figure 4 is a flowchart that shows the order of the manufacturing method of the first embodiment.

[0033] Figure 5 is a view that shows an electric wire connector of a second embodiment of the present application.

[0034] Figure 6 is a view that shows a manufacturing method of the second embodiment of the present application.

[0035] Figure 7 is a view that shows the manufacturing method of the second embodiment. Figure 6 ​​

[0036] Figure 8 is a flowchart showing the sequence of the manufacturing method of the second embodiment.

[0037] Figure 9 is a diagram explaining the manufacturing method of the third embodiment of the present application.

[0038] Figure 10 is a diagram explaining the manufacturing method of the third embodiment. Figure 9

[0039] Figure 11 is a flowchart showing the sequence of the manufacturing method of the third embodiment.

[0040] Figure 12 is a diagram explaining the manufacturing method of the fourth embodiment of the present application.

[0041] Figure 13 is a diagram explaining the manufacturing method of the fourth embodiment. Figure 10

[0042] Figure 14 is a flowchart showing the sequence of the manufacturing method of the fourth embodiment.

[0043] Figure 15 is a diagram showing a specific application example of the wire connector of the present application.

[0044] Figure 16 is a diagram showing another specific application example of the wire connector of the present application. DETAILED DESCRIPTION

[0045] Hereinafter, embodiments of the wire connector and the manufacturing method of the wire connector of the present application will be explained with reference to the accompanying drawings. The present embodiment is such that the metal portions of the wires are fused and solidified by irradiation of laser light to obtain the connector, but the connecting portions of the pair of wires are held by an insulating cover such as a resin material which transmits the laser light (hereinafter, simply referred to as laser light) at the time of the fusion and solidification. Thereby, the connecting portions of the pair of wires are aligned by guiding the connecting portions by the insulating cover, and thus the connecting portions can be easily connected in the butted state.

[0046] Hereinafter, after sequentially explaining four embodiments, a specific application example of the wire connector of the present embodiment will be explained.

[0047] [First Embodiment: Figure 1 , Figure 2 , Figure 3 , Figure 4 ]

[0048] As Figure 1 ​​As shown, the electric wire connector 1A of the first embodiment has a first electric wire 10A and a second electric wire 20A electrically connected to the first electric wire 10A. The core wire 11 of the first electric wire 10A is mechanically and electrically connected to the second electric wire 20A by the connecting portion 30 housed inside the insulating covering 13. Further, with respect to the electric wires, the side to which the second electric wire 20A of the first electric wire 10A is connected is defined as front (F) and the opposite side thereof is defined as back (B).

[0049] [First electric wire 10A, second electric wire 20A, connecting portion 30: Figure 1 ]

[0050] The first electric wire 10A has a core wire 11 and an insulating covering 13 covering the outer periphery of the core wire 11.

[0051] The core wire 11 is composed of a metal material such as copper and copper alloy, nickel and nickel alloy, and iron-based alloy, which have excellent electrical conductivity. In addition, a material on which surface treatment such as plating is performed on the surface of these metal materials, such as a material on which copper or copper alloy is plated with nickel or tin, can be used. In addition, as the core wire 11, either a single wire or a twisted wire can be applied.

[0052] The insulating covering 13 is composed of a material having a sufficiently small absorption rate of laser light compared to the core wire 11, in addition to being composed of an electrically insulating material. The reason for this is that, in the present embodiment, the core wire 11 of the first electric wire 10A and the second electric wire 20A are joined by welding by irradiation of laser light, but at the time of this joining, the laser light is transmitted through the insulating covering 13 and irradiated to the connecting portion of the core wire 11 and the second electric wire 20A. The insulating covering 13 is composed of a material capable of achieving this purpose, such as a resin material such as acrylic, PC (polycarbonate), PVC (polyvinyl chloride), PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), and the like, a fluororesin, and glass, or the like. As the fluororesin, PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), or the like can be applied. Among these, from the viewpoint of heat resistance, glass, a fluororesin is preferable.

[0053] With respect to the inner diameter of the insulating covering 13, an example in which the wire diameter of the second electric wire 20A is the same as that is shown here, but the wire diameter of the second electric wire 20A can be made smaller as shown in the application examples described later. The wire diameter referred to here means the diameter.

[0054] In the present embodiment, the second electric wire 20A is composed only of a conductor and is composed of the same metal material as the core wire 11. However, the outer diameter (R20) of the second electric wire 20A in the first embodiment is preferably in a relationship of R20≤R11 with the outer diameter (R11) of the core wire 11. This relationship results from a manufacturing method of the electric wire connector 1A described later. In addition, in the present embodiment, R11 and R20 are not limited, but according to the manufacturing method of the electric wire connector 1A, it is possible to join the core wire 11 and the front end surface of the second electric wire 20A to each other with a fine wire of 5 mm or less, further 3 mm or less.

[0055] The connection destination of the portion of the first electric wire 10A and the second electric wire 20A that is forward of the broken line is arbitrary and can be connected to an electrical component, a power source, a measuring device, or the like.

[0056] [Connection portion 30: Figure 1 ]

[0057] The connection portion 30 that connects the core wire 11 of the first electric wire 10A and the second electric wire 20A is formed by solidification after melting of both the core wire 11 and the second electric wire 20A. Although the connection portion 30 is interposed, the front end surfaces of the core wire 11 and the second electric wire 20A are joined to each other. The melting for forming the connection portion 30 is performed by irradiation of laser (LASER: Light Amplification by Stimulated Emission of Radiation) as described later.

[0058] As shown in Figure 1 , the connection portion 30 is provided inside the insulating cover 13 that is provided in advance to the first electric wire 10A. In this way, the first electric wire 10A and the second electric wire 20A are joined inside the insulating cover 13, and thus it is possible to omit the insulating cover as another component that insulates the connection portion 30. In this case, the outer diameter of the insulating cover 13 that houses the connection portion 30 is limited to a range equivalent to other portions.

[0059] The connection portion 30 is equivalent to the outer peripheral surfaces of the core wire 11 and the second electric wire 20A, or is limited to a range of a small amount even if it exceeds the outer peripheral surfaces. The reason for this is that, in a molten state before the connection portion 30 is formed, expansion to the radial outside is limited by the insulating cover 13.

[0060] [Manufacturing method of electric wire connector 1A: Figure 2 、 Figure 3 、 Figure 4 ]

[0061] Next, the manufacturing method of the electric wire connector 1A will be described with reference to Figure 2 、 Figure 3 , and Figure 4A manufacturing method of the electric wire connector 1A will be described.

[0062] As shown in Figure 4 , the manufacturing method includes the following steps.

[0063] S101: A step of cutting the end portion of the first electric wire

[0064] S103: A first laser irradiation step

[0065] S105: A step of solidifying / shrinking the core wire of the first electric wire after laser irradiation

[0066] S107: A step of inserting the front end portion of the second electric wire into the pocket and butting it against the first electric wire

[0067] S109: A second laser irradiation step

[0068] S111: A step of solidifying / joining the portion after laser irradiation

[0069] Hereinafter, each step will be described with reference to Figure 2 and Figure 3 in order of S101 to S111.

[0070] < The step of cutting the end portion of the first electric wire (S101): Figure 2 (a) of

[0071] First, as shown in (a) of Figure 2 , the end portion of one side of the first electric wire 10A is cut and the front end face 10E is finished into a flat face. The same is done for the second electric wire 20A on the object side. By so doing, the butting state of the first electric wire 10A and the second electric wire 20A becomes good.

[0072] < The first laser irradiation step (S103): Figure 2 (b) of

[0073] Next, as shown in (b) of Figure 2 , the first laser LA1 is irradiated to the portion facing the front end face 10E of the first electric wire 10A. The first laser LA1 transmits the insulating covering 13 to reach the core wire 11, and melts the core wire 11. The first laser LA1 to be irradiated has a spot diameter required to melt the core wire 11 in the vicinity of the front end face 10E, and a spot diameter equal to or smaller than the wire diameter of the core wire 11 is preferably used.

[0074] As the first laser LA1, for example, a YAG laser using a solid laser of Yttrium Aluminum Garnet (YAG) can be used. The wavelength of the YAG laser is 1064 nm, and the absorbance of the YAG laser of the core wire 11 and the insulating covering 13 has a relationship of core wire 11 « insulating covering 13. The absorbance of the YAG laser of several materials constituting the core wire 11 and the insulating covering 13, respectively, is as described below.

[0075] Further, the reflectance of the material constituting the core wire 11 is indicated together with the absorbance, and the transmittance of the material constituting the insulating covering 13 is indicated together with the absorbance. In addition, the wavelength of the YAG laser is 1064 nm.

[0076] Material constituting the core wire 11 (in the order of reflectance, absorbance)

[0077] Stainless steel: 55%, 45% nickel: 12%, 88%

[0078] Copper: 75%, 25% aluminum: 74%, 26%

[0079] Material constituting the insulating covering 13 (in the order of transmittance, absorbance)

[0080] PTFE: 90%, 10% PE: 89%, 11% PC: 91%, 9%

[0081] PET: 91%, 9% PVC: 53%, 47%

[0082] Glass: 92%, 8% Acrylic: 92%, 8%

[0083] By irradiating the first laser LA1, the laser irradiation region of the core wire 11 and its vicinity are melted. The core wire 11 is a metal material, and thus the temperature at the time of melting is high, for example, the melting point of copper is 1084.6°C, and the melting point of nickel is 1455°C. Therefore, there is a concern that heat due to the melting of the core wire 11 damages the insulating covering 13, but by focusing the spot diameter, the core wire 11 can be melted in a short time, for example, 10 msec., and thus the damage of the heat to the insulating covering 13 can be suppressed to be small.

[0084] <Process of solidifying / shrinking the core wire after laser irradiation (S105)>: Figure 2 (c) of the above

[0085] When the irradiation of the first laser LA1 ends after the prescribed time elapses, the molten core wire 11 metal material constituting the solidified portion SP cools and forms. The volume of the solidified portion SP decreases during solidification from the state of the core wire 11. The decrease in volume occurs toward the rear (B) of the first electric wire 10A to which the core wire 11 is connected. Thus, inside the insulating covering 13 located forward (F) of the solidified portion SP, a void is generated due to the decrease in volume. This void is referred to as a pocket 12 of the first electric wire 10A.

[0086] As above, the solidification / contraction process can exert both the first function of forming the solidified portion SP and the second function of forming the pocket 12.

[0087] <Process of inserting the second electric wire into the pocket (S107) : Figure 3 (a) of

[0088] After the pocket 12 is formed in the first electric wire 10A, the second electric wire 20A, which is the joining object of the first electric wire 10A, is inserted into the pocket 12. As shown in (a) of Figure 3 (a), the insertion is performed in such a manner that the front end face 20E of the second electric wire 20A is butted against the solidified portion SP of the first electric wire 10A.

[0089] During the insertion of the second electric wire 20A and the butting against the solidified portion SP, the insulating covering 13 around the pocket 12 functions as a guide for the second electric wire 20A. Thus, according to the present embodiment, as long as the second electric wire 20A is inserted into the pocket 12, the alignment of the front end face 20E of the second electric wire 20A with the front end face 11E of the solidified portion SP is easy. Further, in the present embodiment, an example is shown in which the core wire 11 of the first electric wire 10A and the outer diameter (R11, R20) of the second electric wire 20A have the same diameter, but even if the outer diameter (R20) of the second electric wire 20A is smaller than the outer diameter (R11) of the core wire 11, the guiding function of the pocket 12 and the insulating covering 13 is effective.

[0090] <Process of irradiating the second laser (S109) : Figure 3 (b) of

[0091] After the front end face 20E of the second electric wire 20A is butted against the solidified portion SP of the first electric wire 10A, as shown in (b) of Figure 3 (b), the second laser LA2 is irradiated toward the second electric wire 20A and the solidified portion SP for the butted portion and its vicinity. By the irradiation of the second laser LA2, the laser irradiation regions of the second electric wire 20A and the solidified portion SP and their vicinity are molten, and the second electric wire 20A and the core wire 11 are joined by subsequent solidification. The second laser LA2 can be irradiated with the same kind of laser, irradiation time, and the like as the first laser LA1.

[0092] <Process of solidifying / joining the portion irradiated with the laser light> Figure 3 (c) of the above

[0093] When the irradiation of the second laser light LA2 is ended after the second laser light LA2 is irradiated for a prescribed time, the metal material constituting the molten second electric wire 20A and the core wire 11 is cooled to form the connection portion 30, and the electric wire connection body 1A is obtained. The connection portion 30 of the electric wire connection body 1A is disposed inside the insulating cover 13 provided in advance to the first electric wire 10A.

[0094] [Effects exerted by the first embodiment]

[0095] Hereinafter, the effects exerted by the electric wire connection body 1A of the first embodiment and the manufacturing method thereof will be described.

[0096] [Effects exerted by the electric wire connection body 1A]

[0097] <Downsizing / space saving of the electric wire connection body 1A>

[0098] The radial dimension of the insulating cover 13 of the electric wire connection body 1A can be suppressed from becoming large by the insulating cover 13. That is, the connection portion 30 of the electric wire connection body 1A is covered by the insulating cover 13 of the first electric wire 10A, and thus the insulating cover 13 can be converged to the same radial dimension as before the connection portion 30 is formed.

[0099] In addition, in the case where the electric wire connection body 1A is provided to various kinds of equipment, since the radial dimension can be suppressed, the space where the electric wire connection body 1A is provided can be narrowed. Thus, by saving the space where the electric wire connection body 1A is provided, the downsizing of the equipment can also be facilitated.

[0100] In addition, the connection of the core wire 11 and the second electric wire 20A is performed by butt welding, and thus, for example, a connection member such as a connection terminal is not required, and the radial dimension of the connection portion 30 itself can be suppressed.

[0101] Furthermore, the connection portion 30 is housed inside the insulating cover 13, and thus, in the case where, for example, a sensing detection element is provided to the other end of the second electric wire 20A, the dimension from the front end surface 10E of the first electric wire 10A to the sensing detection element can be shortened. Specific examples of the equipment provided with the sensing detection element will be described later.

[0102] <High responsiveness according to use>

[0103] For protection from the surrounding environment, for example, in the case of applying the wire connector 1A to a temperature sensor housed in a protective tube made of metal, the temperature sensor can be housed in a small-diameter protective tube. Thus, heat conduction from the protective tube to the temperature sensor element can be performed quickly, and thus high-response temperature measurement can be performed. The wire connector 1A can be applied to a sensor detection element other than a temperature sensor, and thus high-response sensor detection can be performed in this case as well.

[0104] <Improvement of withstand voltage performance>

[0105] The wire connector 1A is welded or joined so that the core wire 11 and the second wire 20A are butted, and the connection portion 30 is housed inside the insulating cover 13. Thus, the outer peripheral surface of the connection portion 30 is flat and has no protrusions, and in addition, since there is also no connection terminal, there is also no concavo-convex based on the connection terminal. For example, since the connection portion 30 is housed in the insulating cover 13, the insulating distance from the external environment to the connection portion 30 becomes difficult to approach, and thus the withstand voltage performance is improved.

[0106] <Improvement of stress resistance of the connection portion 30>

[0107] The connection portion 30 is housed inside the insulating cover 13, and thus stress from the outside is difficult to apply to the connection portion 30, and the risk of disconnection of the connection portion 30 is reduced.

[0108] [Effects of the manufacturing method of the wire connector 1A]

[0109] Next, the effects of the manufacturing method of the wire connector 1A described with reference to Figures 2-4 to the wire connector 1A are described.

[0110] <Easier thin wire joining>

[0111] According to the manufacturing method of the present embodiment, the insulating cover 13 that surrounds the pocket 12 functions as a guide, and thus the alignment of the core wire 11 and the second wire 20A is easier compared to the case where the surrounding does not have any function as a guide. In addition, even in the case where the wire diameters of the core wire 11 and the second wire 20A are different, the influence thereof can be reduced. Thus, thin wire joining of the conductor and the functional element can be easily achieved. For example, butt-based connection of a wire diameter of about 0.10 mm can be performed.

[0112] <Simplification of welding work>

[0113] Generally, in laser welding of wires to each other, 2 wires need to be butted with high precision for joining, but according to the manufacturing method, the insulating cover 13 functions as a guide. Therefore, alignment becomes easy, not only equipment for alignment and the like are simplified, but also welding operability is improved, and automation also becomes easy.

[0114] Particularly, in the case of a wire with a small wire diameter, alignment of butting 2 wires for joining becomes more difficult, and thus effectiveness of the method increases.

[0115] In addition, the connecting portion is formed in the insulating cover, and thus trouble of insulating treatment of the connecting portion is omitted.

[0116] [Second Embodiment: Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 ]

[0117] Next, the wire connecting body 1B of the second embodiment will be described.

[0118] As shown in Figure 5 , the wire connecting body 1B of the second embodiment has a first wire 10B and a second wire 20B electrically connected to the first wire 10B. The core wire 11 of the first wire 10B and the core wire 21 of the second wire 20B are mechanically and electrically connected by the connecting portion 30 housed inside the insulating tube 40. The wire connecting body 1B has both the first wire 10B and the second wire 20B to be joined, and has the core wires 11, 21 and the insulating covers 13, 23. The insulating tube 40 is separate from the first wire 10B and the second wire 20B.

[0119] The first wire 10B and the second wire 20B can be applied to the same material and constitution as the first wire 10A and the second wire 20A of the first embodiment, and thus a manufacturing method of the wire connecting body 1B will be described below.

[0120] [Manufacturing Method of Wire Connecting Body 1B: Figure 6 、 Figure 7 、 Figure 8 ]

[0121] The manufacturing method of the wire connecting body 1B will be described with reference to Figure 6 、 Figure 7 and Figure 8 .

[0122] As shown in Figure 8 , the manufacturing method includes the following steps.

[0123] S201: A step of aligning the first wire, the second wire, and the insulating tube

[0124] S203: A process of inserting the core wire of the first electric wire into the insulating tube

[0125] S205: A process of inserting and butting the core wire of the second electric wire into the insulating tube

[0126] S207: A process of irradiating laser light to the butted portion

[0127] S209: A process of solidifying the region after the laser light irradiation

[0128] Hereinafter, referring to Figure 6 and Figure 7 Each process is explained in the order of S201 to S209.

[0129] Process of aligning the first and second electric wires and the insulating tube (S201): Figure 6 (a) of

[0130] First, as shown in (a) of Figure 6 , the alignment of the center axes C of the first electric wire 10B, the insulating tube 40, and the second electric wire 20B is performed. This is to make the insertion of the core wire 11 and the core wire 21 into the insulating tube 40 easy. As a prerequisite for this alignment process, the following processing is performed.

[0131] As shown in (a) of Figure 6 , for the end portion of one of the first electric wire 10B and the second electric wire 20B, the insulating cover 13 and the insulating cover 23 are peeled off, and the core wire 11 and the core wire 21 are stripped out. The amount of stripping out in the direction of the center axis C is arbitrary, but after the core wire 11 and the core wire 21 are inserted into the insulating tube 40, the front end faces 10E and 20E of both need to be butted. Thus, the stripped lengths L11 and L21 of the core wire 11 and the core wire 21 have the following relationship of formula (1) with the overall length L40 of the insulating tube 40. Furthermore, as can be clearly seen from Figure 5 , the electric wire connection body IB has the relationship of formula (2). Thus, the core wire 11 and the core wire 21 can be shielded by the insulating tube 40. In addition, as shown in formula (3), as the electric wire connection body IB, an example is shown in which the stripped length L11 of the core wire 11 is equal to the stripped length L21 of the core wire 21, but the length L11 and the length L21 can also be different.

[0132] L11 + L21 ≥ L40 … formula (1)

[0133] L11 + L21 = L40 … formula (2)

[0134] L11 = L21 … formula (3)

[0135] Further, instead of the insulating tube 40, a tape-shaped insulating material can be wound.

[0136] <Process of inserting the core wire of the first electric wire into the insulating tube (S203) >: Figure 6 (b) of FIG. 10

[0137] If the alignment of the first electric wire 10B, the second electric wire 20B, and the insulating tube 40 is completed, as shown in (b) of FIG. 10, the core wire 11 of the first electric wire 10B is inserted into the inside of the insulating tube 40. The insertion is performed until the insulating covering 13 of the first electric wire 10B is butted against the insulating tube 40. Figure 6

[0138] <Process of inserting the core wire of the second electric wire into the insulating tube (S205) >: Figure 6 (c) of FIG. 11

[0139] If the core wire 11 of the first electric wire 10B is inserted into the insulating tube 40, as shown in (c) of FIG. 11, the core wire 21 of the second electric wire 20B is inserted into the inside of the insulating tube 40. The insertion is performed until the insulating covering 23 of the second electric wire 20B is butted against the insulating tube 40. Figure 6

[0140] In the electric wire connector 1B, since the formula (2) is satisfied, the front end face 10E of the core wire 11 and the front end face 20E of the core wire 21 are butted against each other in the inside of the insulating tube 40. Further, the core wire 11 and the core wire 21 are butted against each other at the middle point of the entire length L40 of the insulating tube 40.

[0141] Here, an example in which the insertion into the insulating tube 40 is performed in the order of the first electric wire 10B and the second electric wire 20B is described, but the insertion can be performed in the order of the second electric wire 20B and the first electric wire 10B, or the first electric wire 10B and the second electric wire 20B can be inserted at the same time.

[0142] <Process of irradiating laser light to the butted portion (S207) >: Figure 7 (a) of FIG. 12

[0143] Next, as shown in (a) of FIG. 12, laser light LA is irradiated to a region including the butted portion of the front end face 10E of the first electric wire 10B and the front end face 20E of the second electric wire 20B. The laser light LA transmits the insulating tube 40 to reach the core wire 11 and the core wire 21, and melts the core wire 11 and the core wire 21. The conditions such as the spot diameter of the irradiated laser light LA can be the same as those of the first embodiment. Figure 7 <Process of solidifying / joining the laser light irradiated portion (S208) >:

[0144] (b) of FIG. 13 Figure 7

[0145] ​​​After a predetermined time has elapsed, irradiation with laser light LA ​​is terminated. The metal material constituting the melted core wires 11 and 21 cools, forming a connection portion 30, resulting in the cable connector 1B. The connection portion 30 of the cable connector 1B is disposed within the insulating tube 40, and the stripped portions of the core wires 11 and 21 are covered by the insulating tube 40, preventing them from being exposed to the outside. The insulating tube 40 preferably has a full length sufficient to accommodate the connection portion 30.

[0146] Alternatively, a tape-shaped insulating material may be wound instead of the insulating tube 40 .

[0147] [Effects of the Second Embodiment]

[0148] The second embodiment exhibits the following effects in addition to the same effects as the first embodiment.

[0149] According to the second embodiment, even electric wires including core wires can be butt-welded simply by preparing insulating tubes.

[0150] Furthermore, according to the second embodiment, the entire lengths of the core wires 11 stripped from the insulation covering 13 and the core wires 21 stripped from the insulation covering 23 are housed inside the insulation tube 40 , eliminating the need for separate insulation coverings.

[0151] [Third embodiment: Figure 9 、 Figure 10 、 Figure 11 ]

[0152] Next, a wire connector 1C according to a third embodiment will be described.

[0153] like Figure 10 As shown in (d) of FIG. , the third embodiment of the wire connector 1C comprises a first wire 10C and a second wire 20C connected via a connecting portion 30. In the first embodiment and the wire connector 1C, instead of insulating the wires, a jig 50 that transmits laser light LA ​​is used. While maintaining the first and second wires 10C in abutted state, the wires 10C and 20C are welded by irradiating the wires with laser light LA. Since the wire connector 1C is a simple method of joining the first and second wires 10C, both made of conductive materials, via the connecting portion 30, a description of the structure will be omitted. The description will begin with the method for manufacturing the first wire 10C.

[0154] [Method for manufacturing electric wire connector 1C: Figure 9 、 Figure 10 、 Figure 11 ]

[0155] Reference Figure 9 、 Figure 10 as well as Figure 11A manufacturing method of the electric wire connector 1C will be described.

[0156] As shown in Figure 11 , the manufacturing method includes the following steps.

[0157] S301: A step of aligning the first electric wire and the second electric wire with respect to the jig

[0158] S303: A step of butting the first electric wire and the second electric wire and fixing with the jig

[0159] S305: A step of irradiating the butted portion with laser light

[0160] S307: A step of solidifying / joining the portion after laser light irradiation

[0161] S309: A step of removing the jig

[0162] Hereinafter, with reference to Figure 9 and Figure 10 , each step will be described in the order of S301 to S309.

[0163] <Step of aligning the first electric wire and the second electric wire with respect to the jig (S301)> Figure 9 (a) of

[0164] First, as shown in (a) of Figure 9 , the first electric wire 10C and the second electric wire 20C are aligned with respect to the jig 50. The alignment is such that the positions of the central axes of the first electric wire 10C and the second electric wire 20C are aligned, and the front end surface 10E of the first electric wire 10C and the front end surface 20E of the second electric wire 20C are disposed between the upper die 51 and the lower die 55 of the jig 50 in a manner that converges within the range of the jig 50. The drive source of the upper die 51 and the lower die 55, the mechanism connecting the drive source and the upper die 51 and the lower die 55 are arbitrary, and thus the description is omitted, but as long as at least one of the upper die 51 and the lower die 55 can be raised and lowered, the third embodiment can be implemented.

[0165] Here, the jig 50 will be described.

[0166] As shown in (a) of Figure 9 and (b) of Figure 9 , the jig 50 has the upper die 51 and the lower die 55.

[0167] The upper die 51 has a die main body 52 and a cavity 53 provided to the face of the die main body 52 opposite to the lower die 55. The cavity 53 is shaped to the outer shape of the first electric wire 10C and the second electric wire 20C, and the shape of the cross section becomes a circular arc shape. In addition, the cavity 53 is formed through along the long direction of the upper die 51.

[0168] The lower die 55 has a die main body 56 and a cavity 57, and has the same configuration as the upper die 51 as shown in (b) of FIG. 6, but is reversed upside down. Thus, the cavity 53 of the upper die 51 and the cavity 57 of the lower die 55 are arranged in opposition to each other. Figure 9

[0169] As for the material constituting the upper die 51 and the lower die 55, it is selected in consideration of the case where the laser light LA is transmitted. For example, when the laser light is irradiated from above the upper die 51 as shown by LA1 in (b) of FIG. 6, the upper die 51 needs to be made of a material that transmits the laser light LA1, but the lower die 55 can be made of a material that does not transmit the laser light LA1. Conversely, when the laser light is irradiated from below the lower die 55 as shown by LA2 in (b) of FIG. 6, the lower die 55 needs to be made of a material that transmits the laser light LA2, but the upper die 51 can be made of a material that does not transmit the laser light LA2. Further, when the laser light LA3 is irradiated from the side of the upper die 51 and the lower die 55 as shown in (b) of FIG. 6, both the upper die 51 and the lower die 55 need to be made of a material that transmits the laser light LA3. However, in this case, as for the regions of the upper die 51 and the lower die 55 where the laser light LA3 is not directly irradiated, they can be made of a material that does not transmit the laser light LA3. Figure 9 Figure 9 Figure 9

[0170] <Process of fixing the first electric wire and the second electric wire by the jig (S303) : (a) of FIG. 7> Figure 10

[0171] After the first electric wire 10C and the second electric wire 20C are aligned with respect to the jig 50, the front end surface 10E of the first electric wire 10C and the front end surface 20E of the second electric wire 20C are butted. The butted first electric wire 10C and second electric wire 20C are arranged within the projected plane of the cavity 53 of the upper die 51 and the cavity 57 of the lower die 55. In the state where the first electric wire 10C and the second electric wire 20C are butted, one or both of the upper die 51 and the lower die 55 are moved so that the interval between the upper die 51 and the lower die 55 disappears. Thus, the first electric wire 10C and the second electric wire 20C are fixed by the jig 50, and the preparation for irradiation of the laser light LA is completed.

[0172] <Process of irradiating the butted portion with the laser light (S305) : (b) of FIG. 7> Figure 10

[0173] ​​​​​​If the first electric wire 10C and the second electric wire 20C are fixed by the jig 50, the laser light LA is irradiated to the butted portions of the first electric wire 10C and the second electric wire 20C and the vicinity thereof, and the irradiated regions of the laser light LA in the first electric wire 10C and the second electric wire 20C and the vicinity thereof are melted. The melted portions are then solidified, whereby the first electric wire 10C and the second electric wire 20C are joined.

[0174] <Process of solidifying / joining the portion irradiated with the laser light (S307) > Figure 10

[0175] If the irradiation of the laser light LA is continued for a prescribed time, the irradiation of the laser light LA is ended. The metal materials constituting the melted first electric wire 10C and the second electric wire 20C are cooled and solidified, whereby the connection portion 30 is formed as shown in (c) of FIG. 6. Figure 10

[0176] <Process of removing the jig (S309) > Figure 10

[0177] If the connection portion 30 is formed, the upper mold 51 and the lower mold 55 are retreated from the first electric wire 10C and the second electric wire 20C, and the jig 50 is removed to obtain the electric wire connection body 1C as shown in (d) of FIG. 6. Figure 10

[0178] As for the obtained electric wire connection body 1C, in a case where the first electric wire 10C and the second electric wire 20C need to be electrically insulated including the connection portion 30, the electric wire connection body 1C is covered with a tape-shaped insulating material (fluororesin resin or the like).

[0179] [Effects exerted by the third embodiment]

[0180] The third embodiment can exert the same effects as the first embodiment, and can exert the following effects.

[0181] According to the third embodiment, even if the electric wires do not have insulating coverings, the electric wire connection body 1C can be obtained by using the jig 50.

[0182] [Fourth embodiment: Figure 12 、 Figure 13 、 Figure 14 ]

[0183] Next, the fourth embodiment will be described.

[0184] The fourth embodiment is the same as the first embodiment in that the pocket 12 is formed, and can obtain the electric wire connection body 1D having the same configuration as the electric wire connection body 1A obtained in the first embodiment. Figure 13 ​​​​of (d)). However, the forming method of the pocket 12 of the fourth embodiment is different from that of the first embodiment. Hereinafter, the manufacturing method of the electric wire connector 1D of the fourth embodiment will be described.

[0185] [Manufacturing method of electric wire connector 1D: Figure 12 、 Figure 13 、 Figure 14 ]

[0186] The manufacturing method of the electric wire connector 1D will be described with reference to Figure 12 、 Figure 13 and Figure 14 .

[0187] As shown in Figure 14 , the manufacturing method includes the following processes.

[0188] S401: Process of first laser irradiation to first electric wire

[0189] S403: Process of removing and breaking by melting the portion on the front end side than the portion melted by laser irradiation

[0190] S405: Process of inserting the front end portion of the second electric wire into the pocket

[0191] S407: Process of irradiating the second laser to the butting portion

[0192] S409: Process of solidifying / joining the portion after laser irradiation

[0193] Hereinafter, each process will be described in the order of S401 to S411 with reference to Figure 12 and Figure 13 .

[0194] Process of first laser irradiation (S401): Figure 12 (a), (b), (c) of

[0195] As shown in (a) of Figure 12 , the first electric wire 10D prepared in the fourth embodiment is such that the core wire 11 is exposed from the front end face 13E of the insulating cover 13. The size of the exposure is only required to be able to hold the core wire 11 and pull it at the time of breaking later.

[0196] The laser LA is irradiated from the insulating cover 13 of the first electric wire 10D on which the core wire 11 is exposed. As shown in (b) of Figure 12 , the position of the laser LA irradiation is a position that is separated by a prescribed distance from the front end face 13E of the insulating cover 13 toward the rear (B) of the first electric wire 10D. This position is the minimum condition that the portion melted by the laser LA irradiation does not reach the front end face 13E of the insulating cover 13.

[0197] By the irradiation of the laser LA, as shown in (c) of FIG. 6, a molten region MP is formed in the core wire 11. This molten region MP becomes a starting point of the next fusion cutting process. Figure 12

[0198] <Process of cutting the portion closer to the front end than the molten portion (S403) > (d) of FIG. 5 Figure 12

[0199] In the process of forming the molten region MP by the irradiation of the laser LA, as shown in (d) of FIG. 5, the first electric wire 10D including the insulating cover 13 is pulled toward the front (F) with respect to the portion of the core wire 11 exposed from the insulating cover 13. Thereby, the portion of the core wire 11 closer to the front (F) than the molten region MP is pulled off to cut the core wire 11. Then, the portion corresponding to the molten region MP is cooled to form a solidified portion SP, SP. In the inside of the insulating cover 13, the portion where the core wire 11 is pulled off becomes a pocket 12. Thus, in the fourth embodiment, the pocket 12 is formed by cutting the core wire 11 housed in the insulating cover 13. Figure 12 <Process of inserting the second electric wire into the pocket (S405) > (a), (b) of FIG. 6

[0200] Figure 13 After the pocket 12 is formed in the first electric wire 10A, the second electric wire 20A, which is the joining object of the first electric wire 10A, is inserted into the pocket 12. As shown in (b) of FIG. 6, the insertion is performed in such a manner that the front end face 20E of the second electric wire 20A is butted against the solidified portion SP of the first electric wire 10A.

[0201] In the process of the insertion of the second electric wire 20A, butting against the solidified portion SP, the insulating cover 13 around the pocket 12 functions as a guide for the second electric wire 20A. Thereby, according to the present embodiment, if the second electric wire 20A is inserted into the pocket 12, the alignment of the front end face 20E of the second electric wire 20A with the solidified portion SP is easily performed. Further, in the example shown here, the outer diameter (R11, R20) of the core wire 11 of the first electric wire 10A is the same as that of the second electric wire 20A, but even if the outer diameter (R20) of the second electric wire 20A is smaller than the outer diameter (R11) of the core wire 11, the guiding function of the pocket 12 and the insulating cover 13 is effective. Figure 3 <Process of performing the second laser irradiation (S407) > (c) of FIG. 6

[0202] If the front end face 20E of the second electric wire 20A is butted against the solidified portion SP of the first electric wire 10A, as shown in (c) of FIG. 6, the laser LA is irradiated to the portion of the core wire 11 of the first electric wire 10A exposed from the insulating cover 13. Thereby, a molten region MP is formed in the core wire 11. This molten region MP becomes a starting point of the next fusion cutting process.

[0203] Figure 13

[0204] Figure 3 ​​​​​​As shown in (b), the second electric wire 20A and the solidified portion SP are irradiated with the second laser beam LA2 at the butted portion and its vicinity. Irradiation with the second laser beam LA2 melts the laser-irradiated region of the second electric wire 20A and the solidified portion SP and its vicinity. This allows subsequent solidification to join the second electric wire 20A and the core wire 11. The second laser beam LA2 can be applied in parallel with the first laser beam LA1.

[0205] <Step of solidifying and joining the laser-irradiated portion (S407): Figure 13 (c) and (d)

[0206] When the irradiation of the second laser beam LA2 ends after a predetermined time, the metal material constituting the melted second electric wire 20A and the core wire 11 cools to form a connection portion 30 , thereby obtaining the electric wire connector 1D.

[0207] [Effects of the Fourth Embodiment]

[0208] The fourth embodiment can produce the following effects in addition to the same effects as those of the first embodiment.

[0209] According to the fourth embodiment, Figure 13 As shown in (d), the connection portion 30 is located in a portion extending inward from the end surface of the insulating covering 13. Thus, the insulating covering 13 acts as a guide, stabilizing the formation of the connection portion 30. Furthermore, assuming that the second electric wire 20D includes an insulating covering, it is easier to form an insulating structure for the wire connector 1D as a whole. That is, even if the second electric wire 20D includes an insulating covering, the connection portion 30 is in a state where no insulating covering exists for the second electric wire 20D. This portion without the insulating covering can be easily inserted into the insulating covering 13 of the first electric wire 10D, making it easier to form an insulating structure for the connector as a whole.

[0210] [Examples of applications of the electric wire connectors 1A to 1D: Figure 15 、 Figure 16 ]

[0211] Next, two specific application examples of the electric wire connection bodies 1A to 1D according to the first to fourth embodiments will be described. Each of the application examples described here is related to a temperature sensor element.

[0212] <First application example (temperature sensor element 100A): Figure 15 >

[0213] like Figure 15As shown, the temperature sensor element 100A of the first use example is provided with a heat sensing body 111 as a detection body, a glass-made protective layer 113 covering the periphery of the heat sensing body 111, and a pair of electric wire connecting bodies 1A, 1A electrically connected to the heat sensing body 111.

[0214] As explained in the first embodiment, the electric wire connecting body 1A is provided with a first electric wire 10A and a second electric wire 20A. The first electric wire 10A is provided with a core wire 11 composed of a twisted wire and an insulating covering 13 covering the core wire 11. The second electric wire 20A is composed of a single wire without an insulating covering. However, the second electric wire 20A has a smaller wire diameter than the core wire 11 of the first electric wire 10A. For example, the core wire 11 has a wire diameter (diameter) of 0.36 mm, while the second electric wire 20A has a wire diameter of 0.07 mm.

[0215] Further, in the temperature sensor element 100A, as shown in Figure 15 the side on which the heat sensing body 111 is provided is defined as the front F, and the side on which the first electric wire 10A is pulled out is defined as the back B. The definitions are relative definitions.

[0216] [Heat sensing body 111]

[0217] The heat sensing body 111 preferably uses, for example, a thermistor. The thermistor is a metal oxide that detects temperature using the property that resistance changes according to temperature.

[0218] The thermistor is classified into an NTC (negative temperature coefficient) thermistor and a PTC (positive temperature coefficient) thermistor, but either thermistor can be used in the present application.

[0219] [Protective layer 113]

[0220] As shown in Figure 15 the glass-made protective layer 113 seals the heat sensing body 111 to maintain an airtight state, thereby preventing chemical and physical changes of the heat sensing body 111 due to the surrounding environmental conditions used for the temperature sensor element 100A, and mechanically protecting the heat sensing body 111.

[0221] The glass-made protective layer 113 covers the front ends of the second electric wires 20A, 20A in addition to the entire heat sensing body 111, and seals the second electric wires 20A, 20A.

[0222] [First electric wire 10A]

[0223] AsFigure 15 As shown, the first electric wire 10A includes a core wire 11 made of a conductor and an insulating covering 13 covering the core wire 11. The pair of first electric wires 10A and 10A2 are two-core parallel wires, or simply "parallel wires." The core wire 11 of the first electric wire 10A is connected to the second electric wire 20A via a connecting portion 30 by welding.

[0224] The core wire 11 of the first electric wire 10A is not subject to restrictions on the linear expansion coefficient as in the second electric wire 20B, and any material can be selected as long as it has predetermined heat resistance and aging resistance.

[0225] [Second electric wire 20A]

[0226] like Figure 15 As shown, the second electric wire 20A used in the temperature sensor element 100A is electrically connected to an electrode of a heat-sensitive body 111 (not shown).

[0227] The second electric wire 20A is sealed by a glass protective layer 113, so Dumet wires, which have a linear expansion coefficient close to that of glass, can be used effectively. Dumet wires are made of an alloy primarily composed of iron and nickel as a core wire, surrounded by copper.

[0228] [Other additional elements]

[0229] The temperature sensor element 100A may include elements other than the above elements.

[0230] For example, a protection tube covering the main portion of the temperature sensor element 100A and a filling body interposed between the temperature sensor element 100A and the protection tube may be provided.

[0231] The protection tube is preferably made of copper or copper alloy having high thermal conductivity, and protects the temperature sensor element 100A housed therein from the influence of the ambient gas, while being able to quickly transfer the temperature of the ambient gas to the interior.

[0232] <Second application example (temperature sensor element 100B): Figure 16 >

[0233] like Figure 16 As shown, the temperature sensor element 100B of the second application example includes a heat-sensitive element 111, a glass protective layer 113 covering the periphery of the heat-sensitive element 111, and a pair of wire connectors 1A, 1A directly electrically connected to the heat-sensitive element 111. The elements up to this point are common to the temperature sensor element 100A. The temperature sensor element 100B includes a ceramic protective tube 115 on the rear end of the glass protective layer 113.

[0234] like Figure 16 As shown, the protection tube 115 is joined to the rear end portion of the protection layer 113 from which the second electric wire 20A is pulled out, thereby mechanically reinforcing the protection layer 113 and improving electrical insulation and mechanical strength.

[0235] Protection tube 115 is made of a sintered body such as alumina (Al2O3) or silicon nitride (Si3N4) having higher mechanical strength than protection layer 113. Protection tube 115 has through holes (not shown) through which the two second electric wires 20A, 20A are inserted.

[0236] The second electric wire 20A has a wire diameter of about 0.1 to 1.0 mm as an example. In addition, the core wire 11 has a wire diameter of about 0.5 to 2.0 mm as an example.

[0237] While preferred embodiments of the present invention have been described above, the configurations listed in the above embodiments may be selected or replaced with other configurations without departing from the spirit of the present invention.

[0238] For example, in the above embodiments, temperature sensor elements are used as the application object, but the electric wire connector of the present invention can also be applied to other objects, such as micro heaters, light emitters, vibrators, micro motors, etc.

[0239] Explanation of symbols

[0240] 1A, 1B, 1C, 1D wire connectors

[0241] 10A, 10B, 10C, 10D first wire

[0242] 11, 21 core wire

[0243] 12 pockets

[0244] 13, 23 Insulation covering

[0245] 20A, 20B, 20C, 20D Second wire

[0246] 21 core wire

[0247] 23 Insulation Cover

[0248] 30 Connection

[0249] 40 Insulation tube

[0250] 50 fixture

[0251] 51 upper mold

[0252] 52 mold body

[0253] 53 Cavity

[0254] 55 lower mold

[0255] 56 mold body

[0256] 57 cavity

[0257] 100A, 100B temperature sensor element

[0258] 111 heat sensitive body

[0259] 113 protective layer

Claims

1. An electric wire connector characterized by comprising: Possessing: a first electric wire; a second electric wire electrically connected to the first electric wire; and a connecting portion connecting the first electric wire and the second electric wire, either of the first electric wire and the second electric wire has a core wire and an insulating covering covering an outer circumference of the core wire, the insulating covering is provided in advance to either of the first electric wire and the second electric wire, a gap in which the core wire is not present is formed inside the insulating covering by irradiating the core wire with laser light through the insulating covering, the connecting portion is formed by butt welding the first electric wire and the second electric wire in the gap inside the insulating covering.

2. The electric wire connecting body according to claim 1, wherein the insulating covering has an inner diameter equivalent to a wire diameter of either of the first electric wire and the second electric wire, the connecting portion has a wire diameter equivalent to the wire diameter of either of the first electric wire and the second electric wire.

3. The electric wire connecting body according to claim 1 or 2, wherein the insulating covering is composed of a fluororesin.

4. The electric wire connecting body according to claim 1 or 2, wherein an absorbance of laser light of the insulating covering of the first electric wire is lower than an absorbance of laser light of the core wire of the first electric wire.

5. A sensor element, possessing: a detection body; and a pair of the electric wire connecting bodies according to any one of claims 1 to 4 electrically connected to the detection body.

6. A method of manufacturing an electric wire connector for connecting a first electric wire and a second electric wire by butt welding, characterized by, Possessing: a pocket forming process of forming a gap in which a core wire is not present inside an insulating covering by irradiating the core wire covered with the insulating covering with laser light, the insulating covering being provided in advance to either of a first electric wire and a second electric wire; a butting process of butting end faces of the first electric wire and the second electric wire to each other in the gap inside the insulating covering; and an irradiation process of forming a connecting portion based on welding by irradiating the first electric wire and the second electric wire after butting with laser light.

7. The electric wire connecting body manufacturing method according to claim 6, wherein in the pocket forming process, the gap is formed by volume reduction accompanying melting and solidification of the core wire due to irradiation of the laser light to the end portion of the core wire.

8. The electric wire connecting body manufacturing method according to claim 6, wherein in the pocket forming process, the gap is formed by melting and removing the core wire from a front end side of the core wire by irradiating the core wire with the laser light.

9. A sensor element manufacturing method of electrically connecting a pair of electric wire connecting bodies and a detection body, characterized by connecting the electric wire connecting bodies and the detection body by the electric wire connecting body manufacturing method according to any one of claims 6 to 8.

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