JPH09239548A - Lead wire connecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent strands in a weld zone from disarraying by removing a prescribed dimension of insulated coating required for welding after immersing the cut end part of a lead wire into a molten solder bath for a prescribed time period. SOLUTION: First, when the lead wire 13 is welded to a terminal member, strands constructing the core wire of the lead wire 13 are possibly disarranged in the case of merely pressing with an electrode. Then, first, the cut end part of the lead wire 13 in the condition leaving it cut is immersed into a flux bath 31 of about 10mm for one to two sec, and next, it is likewise immersed into a molten solder bath 32 of about 10mm for zero point five sec. Thereafter, the core wire 13a of specified dimension L for required for welding is exposed. As the result of it, the solder is penetrated into the end part of the core wire 13a, whereby the disarranging of strands in the core wire 13a is suitably prevented. Moreover, since strands are stuck out when they are sandwiched with the terminal and pressed with the electrode at the time of welding, the real contacting area of the lead wire to the terminal is settled without reducing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead wire connecting method for welding a core wire to a terminal by electric resistance heating.

[0002]

2. Description of the Related Art A conductor of a coil such as an electromagnetic sensor is connected to a lead wire for signal derivation through a relay terminal. Spot welding by electric resistance heating is used as a method of connecting the lead wire to the relay terminal.

[0003]

The spot welding is
Since the core wire of the lead wire is pressed between the electrodes together with the terminal, the wires forming the core wire may be disturbed.
If the strands are disturbed, they will stick out of the weld and come into contact with other parts, the number of strands actually connected to the terminal will decrease, and the connection strength will be insufficient, or the conductive path cross-sectional area will be insufficient. There is an inconvenience.

The present invention has been devised to eliminate such inconvenience, and its main object is to provide a lead wire connecting method capable of preventing the strands of a welded portion from being disturbed. .

[0005]

In order to achieve such an object, according to the present invention, an insulating coating having a prescribed size required for welding after a cut end of a lead wire is immersed in a molten solder bath for a predetermined time. Then, the core wire was welded to the terminal by heat generation by electric resistance.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows an electromagnetic sensor to which the present invention is applied. The electromagnetic sensor 1 is formed by integrally molding a housing part 3 covering the periphery of a sensitive element part 2 described below, a mounting stay part 4 for the vehicle body, and a cable pulling part 5 with a synthetic resin material. In addition, in the mounting stay portion 4,
A metal collar 6 for receiving the bolt tightening force is inserted.

As shown in FIGS. 2 and 3, the sensitive element portion 2 includes a bobbin 7 injection-molded of a synthetic resin material and a pair of terminal members 8 press-fitted and fixed to one axial end surface of the bobbin 7. A coil 9 composed of a conductive wire wound around a bobbin 7 after each end of the bobbin 7 is connected to the pole piece 10, a pole piece 10, a permanent magnet 11 and a yoke 12 mounted in a central hole of the bobbin 7, and a vehicle control The lead wire 13 is connected to the circuit via a connector (not shown).

As shown in FIG. 2, the end of the lead wire 14 of the coil 9 is insulated from the surface of the lead wire by applying a current to the lead wire holding portion 15 of the terminal member 8 with which this end is entangled while crimping the electrode. The layers are melted by heat, the copper layer of the conductive wire 14 and the tin layer plated on the terminal member 8 are melted, and fused to the conductive wire holding portion 15 by fusing.

In the lead wire 13, a copper layer of the core wire of the lead wire 13 and a tin layer plated on the terminal member 8 are formed by applying an electric current to the lead wire holding portion 16 of the terminal member 8 while crimping the electrode. And are melted, and the solder previously applied to the end of the core wire of the lead wire 13 is melted into the entire joint portion and is firmly joined to the lead wire holding portion 16. High-temperature solder is used as the solder.

The lead wires 13 are prevented from slipping by lightly press-fitting the lead wires 13 into the holding grooves 17 formed in the one end surface of the bobbin 7. The lead wire 13 is coated with a cable retainer 18 in advance, as shown in FIG.

The sensitive element portion 2 and the metal collar 6 assembled in this way are set in the lower mold 19 as shown in FIG. 3, and then the upper die 20 is closed to set the outer surface of the sensitive element portion 2 and the lower portion. The gate 21 is provided in the cavity formed between the inner surfaces of the mold 19.
By injecting the molten resin from the housing 3, the housing portion 3 and the stay portion 4 are integrally molded with the sensitive element portion 2 and the collar 6 inserted, as shown in FIG.

As described above, when the lead wire 13 is welded to the terminal member 8, if the insulating coating is simply removed, the strand forming the core wire of the lead wire 13 when pressed by the electrodes. May be disturbed. Therefore, in the present invention, first, the cut end of the lead wire 13 is immersed in the flux bath 31 for about 1 to 2 seconds in the state of being cut off (FIG. 5-A), and then it is similarly melted for about 10 mm by the molten solder. Tank 32
Then, the core wire 13a having a prescribed dimension L (about 5 mm) necessary for welding was exposed (FIG. 5-C). By doing so, the tip portion of the core wire 13a (the area indicated by the symbol S in FIG.
It is possible to suitably prevent the permeation of the solder to disturb the strands of the core wire 13a.

As shown in FIG. 6, when the cutter of the lead wire has a slightly inclined blade C, the cut end of the core wire 13a is slightly separated from the insulating coating 13b (0.1 to 0.1).
A better result can be obtained by exposing it, but solder can penetrate even if the core wire is not completely exposed, so cutting with a general shearing device is sufficient for practical use. .

[0015]

As described above, according to the present invention, by soldering the tip end of the core wire of the lead wire in advance,
Since the solder melted by the heat during welding goes around to the connection part, the connection strength of the lead wire to the terminal is further improved. In addition, by soldering the tip end of the core wire, it is possible to avoid disturbing the core wire.
The welding workability does not decrease, and the wire does not protrude when it is sandwiched between the terminals and pressed against the electrodes during welding, so that the actual contact area of the lead wire with the terminal does not decrease.

[Brief description of drawings]

FIG. 1 is a perspective view of an electromagnetic sensor according to the present invention.

FIG. 2 is a vertical sectional view showing a state in which a sensitive element portion and a collar are set in a mold.

FIG. 3 is a perspective view of a main part of a sensitive element section.

FIG. 4 is a vertical sectional view showing a state in which a sensitive element portion and a collar are molded in a mold.

FIG. 5 is an explanatory diagram of soldering of the lead wire to the core wire.

FIG. 6 is a conceptual diagram showing an example of a cutter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electromagnetic sensor 2 Sensitive element part 3 Housing part 4 Mounting stay part 5 Cable extension part 6 Metal collar 7 Bobbin 8 Terminal member 9 Coil 10 Pole piece 11 Permanent magnet 12 Yoke 13 Lead wire 14 Conductive wire 15 Conductive wire holding portion 16 Lead wire holding Part 17 Holding groove 18 Cable retainer 19 Lower mold 20 Upper mold 21 Resin injection gate 31 Flux tank 32 Solder tank

Claims (1)

[Claims] 1. A lead wire connecting method for welding a core wire to a terminal by heat generation by electric resistance, wherein an insulation coating having a specified dimension necessary for welding after a cut end portion of the lead wire is immersed in a molten solder bath for a predetermined time. A lead wire connecting method, characterized in that.