JP2005025990A - Connection method for electronic part and lead wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection method for an electronic part and a lead wire with which a firm and proper joint condition of the electrode and the lead wire can be obtained by solving a problem that a firm joint condition can not be obtained even if resistance welding of the electrode with large heat capacity and a lead wire with small heat capacity is performed when using copper with large heat conductivity for the electrode and the lead wire. <P>SOLUTION: In a connecting method for resistance welding an end face of the lead wire 5 to the outer circumferential surface of an intermediate electrode 4, a ridge part 11 is projected on an end face of the lead wire, and a projection size of the lead wire of a welding electrode 12 on the lead wire side is about 0.9 mm which is smaller than the diameter of the lead wire and pinched. In a condition where the ridge part is turned sideways to line contact with an outer circumferential surface of an intermediate electrode and the ridge part of the lead wire is pressed on the intermediate electrode, a current for resistance welding is applied between the welding electrode 12 and the welding electrode 13 to perform resistance welding. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a connection method for suitably connecting a lead wire to an electrode in an electronic component such as a gas discharge tube.
[0002]
[Prior art]
Conventionally, as shown in FIG. 7, a gas discharge tube 50 for absorbing a surge current called a gas arrester or a lightning arrester sandwiches an envelope 51 made of an insulating material made of cylindrical ceramics or the like. The copper electrodes 52 are arranged opposite to each other, and an end portion of a copper lead wire is welded to the outer central portion of the copper electrode 52. In the conventional gas-filled discharge tube 50, a lead wire 53 having a copper wire diameter of approximately 1.0 mm is usually resistance-welded to a copper electrode 52 having a diameter of approximately 8 mm using a silver solder. Since copper has a high thermal conductivity, heating to the tip of the lead wire 53 is compared with the copper electrode 52 even if the lead wire 53 is heated through a current with the end face of the lead wire 53 in contact with the center of the copper electrode 52. However, while the wire diameter (cross-sectional area) is small and the heat capacity is small, the temperature immediately rises. On the other hand, the heating through the current to the center of the copper electrode 52 immediately brings the heat to the surroundings and the temperature of the center is reduced. Therefore, it is difficult to perform welding in a state where both portions in contact with each other are raised to a suitable temperature, and it is difficult to obtain a desired welding strength. In contrast, spot welding can be performed in a short time with an instantaneous current, but the welding strength is not so strong as compared to the long-time welding by resistance welding described above. When a large surge current exceeding 10 kA that is used as a lightning arrester passes, there is a possibility that the welded portion may be damaged. (For example, refer to Patent Document 1). Reference numeral 54 denotes an intermediate electrode in the two-section gas-filled discharge tube 50.
[0003]
[Patent Document 1]
JP 55-9399 A [Problems to be Solved by the Invention]
[0004]
The problem to be solved is that when copper having a high thermal conductivity is used, a strong bonding state cannot be obtained even if resistance welding is performed on an electrode having a large heat capacity and a lead wire having a small heat capacity.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a connecting method of the electronic component and the lead wire according to the present invention is a connecting method in which the end surface of the lead wire is resistance-welded to a curved electrode. The portion is brought into line contact with the outer peripheral surface of the electrode and resistance welding is performed.
[0006]
Further, the protruding dimension of the lead wire from the welding electrode that holds and feeds the lead wire in the welding apparatus for welding the electrode and the lead wire is made smaller than the lead wire diameter.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an electronic component 1 connected by the connection method of the present invention, and will be described below by taking a two-section gas-filled discharge tube as an example. Reference numeral 2 denotes two cylindrical envelopes made of an insulating material such as ceramics, 3 denotes a substantially frustoconical oxygen-free copper side electrode disposed at both ends of the envelope 2, and 4 denotes two envelopes 2 Similarly, intermediate copper electrodes 5 and 5 are lead wires made of annealed copper wires connected to the outer central portion of the side electrode 3 and the intermediate electrode 4. Inside the envelope 2, the side electrode 3 and the intermediate electrode 4 face each other with a discharge gap, and a discharge gas is sealed in the discharge space.
[0008]
As shown in FIG. 2, the lead wire 5 to be welded to the intermediate electrode 4 is narrowed from above and below with a cutting blade 10 having an acute tip (one side of the blade is formed as a single blade, and other than the blade edge is aligned substantially straight). The ridge portion 11 is formed to protrude from the cut surface by being pressed and held. As shown in FIG. 3, the ridge 11 has a vertical width of about 30% of the wire diameter, a height of about 10% of the wire diameter, and the amount of displacement of the ridge 11 from the center of the lead wire 5. The wire diameter is about 10%.
[0009]
When the lead wire 5 is resistance-welded to the intermediate electrode 4 using a welding apparatus, as shown in FIG. 4, the lead wire-side welding electrode 12 has a lead wire 5 protruding dimension of about 0.9 mm smaller than the lead wire diameter. The welding electrode 13 on the side of the intermediate electrode 4 holds the outer periphery of the intermediate electrode 4 and makes the ridge 11 face sideways so as to be in line contact with the outer peripheral surface of the intermediate electrode 4. A resistance welding current is passed between the welding electrode 12 and the welding electrode 13 with the ridge 11 of the lead wire 5 pressed against the outer periphery of the electrode 4. Thus, the contact area of the ridge portion 11 with respect to the intermediate electrode 4 is small because it is a line contact, and the heat capacity is reduced by increasing the current density of the joined portion, and the lead wire 5 protruding from the welding electrode 12 and the intermediate portion. By balancing the temperature rise balance (heat balance) with the joint portion of the electrode 4, the lead wire 5 and the intermediate electrode 4 become high in temperature and have a similar melting condition, thereby obtaining a strong and suitable welded state. It is done.
[0010]
When the intermediate electrode 4 and the lead wire 5 are welded, when the lead wire 5 is plated with tin or the like, copper and plated tin or the like are eutectic with the intermediate electrode 4. Since it becomes easier to join, it is preferable that the intermediate electrode 4 is further plated with tin or the like. The plating thickness is preferably about 10 to 14 μm so that the plating extends to a flat surface other than the ridge 11 when cut by the cutting blade 10.
[0011]
FIG. 5 shows the side electrode 3, and a concave portion 6 is provided in the outer central portion of the side electrode 3 having a diameter of about 8 mm, and a truncated cone for connecting the lead wire 5 to the central portion of the concave portion 6. A connecting portion 7 having a shape is protruded. The shape of the connecting portion 7 is such that when the diameter of the lead wire 5 is about 1.0 mm, the tip diameter is 0.7 to 0.9 mm, which is 70 to 90% of the lead wire diameter, and the base end diameter is The lead wire diameter is 1.0 mm which is the same as the lead wire diameter, and the height is 0.7 to 0.9 mm which is 70 to 90% of the lead wire diameter. 8 mm, the base end diameter is 1.0 mm, which is the same as the lead wire diameter, and the height is 0.8 mm which is 80% of the lead wire diameter. Thus, by making the connection part 7 of the side electrode 3 into the truncated cone shape having the above-mentioned dimensions, the current density at the joint portion with the lead wire 5 is increased and the heat capacity is reduced, thereby making it easy to increase the temperature during welding. As a result, weldability is improved and welding strength is ensured.
[0012]
FIG. 6 shows how to use the welding electrode when the lead wire 5 is welded to the connecting portion 7 of the side electrode 3 by a resistance welding apparatus. The welding electrode 8 on the lead wire side holds the lead wire 5, the welding electrode 9 on the side electrode 3 side holds the outer periphery of the side electrode 3, and the tip of the lead wire 5 is brought into contact with the connection portion 7 of the side electrode 3. In this state, power is supplied between the welding electrode 8 and the welding electrode 9 to heat and weld the joint portion. The protruding amount of the lead wire 5 held by the welding electrode 8 is determined by the connection of the side electrode 3 described above. It is set to 0.8 to 0.85 mm so as to be almost the same as the capacity (volume) of the portion 7. In this way, the balance (heat balance) of the temperature rise between the connecting portion 7 that is a joint portion and the lead wire 5 protruding from the welding electrode 8 is balanced, so that the connecting portion 7 and the lead wire 5 are the same during resistance welding. As a result of melting, a strong and suitable welded state can be obtained.
[0013]
【The invention's effect】
As described in detail above, according to the method for connecting an electronic component and a lead wire of the present invention, in the connection method of resistance welding the end surface of the lead wire to a curved electrode, a ridge portion is formed to protrude from the end surface of the lead wire. When the ridge is brought into line contact with the outer peripheral surface of the electrode and resistance welding is performed, when the ridge is brought into contact with the electrode and the resistance welding current flows, the contact area of the ridge is small and the current density of the joint portion is small. In addition, the heat capacity is reduced, the temperature of the joined portion is easily increased, and the weldability is improved.
[0014]
Moreover, the lead wire and electrode which protrude from a welding electrode are made by making the protrusion dimension of the said lead wire from the welding electrode which hold | maintains and feeds a lead wire in the welding apparatus which welds an electrode and a lead wire smaller than a lead wire diameter. The balance of the temperature rise with the joint portion (heat balance) is balanced, so that the lead wire and the electrode are heated at the time of resistance welding and the same melting condition is obtained, so that a strong and suitable welding state is obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing electronic components connected by a connection method of the present invention.
FIG. 2 is an explanatory view showing a state in which a lead wire welded to an intermediate electrode in the electronic component of the present invention is cut.
FIG. 3 is an explanatory view showing a lead wire end face in the electronic component of the present invention.
4A and 4B show a state in which a lead wire is welded to a joint portion of an intermediate electrode in an electronic component of the present invention, where FIG. 4A is a front view and FIG. 4B is a side view.
5A and 5B show side electrodes of the electronic component of the present invention, in which FIG. 5A is a front view and FIG. 5B is a side sectional view.
FIG. 6 is an explanatory view showing a state in which a lead wire is welded to a connection portion of a side electrode in the electronic component of the present invention.
FIG. 7 is a cross-sectional view showing a conventional electronic component.
[Explanation of symbols]
1: Electronic component 2: Envelope 3: Side electrode 4: Intermediate electrode 5: Lead wire 6: Recess 7: Connection part 8: Welding electrode 9: Welding electrode 10: Cutting blade 11: Ridge 12: Welding electrode 13: Welding electrode

Claims (2)

In a connection method of resistance welding the end face of a lead wire to a curved electrode, an electron is formed by projecting a ridge portion on the end surface of the lead wire, and making the ridge portion line contact with the outer peripheral surface of the electrode and performing resistance welding How to connect lead wires to parts. 2. The electronic component and the lead wire according to claim 1, wherein a protruding dimension of the lead wire from a welding electrode for holding and feeding the lead wire in a welding apparatus for welding the electrode and the lead wire is smaller than a lead wire diameter. Connection method.

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