JPH0468781B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for holding terminals of insert molded parts.

"Prior Art" A terminal holding method for an insert molded part in which a part of the terminal is embedded in the synthetic resin material by insert molding of a synthetic resin material to hold the terminal is used for electronic components used in electronic communication devices or computer devices. It is also widely used in mechanical parts.

Setting switch 1 for initially setting logical values (“1” or “0”) to each part of the digital logic circuit
For example, as shown in Fig. 2, a plurality of slide switches are housed in one case 2, and the terminals 3 of each of these switches are lined up in two rows on both sides of the case and are held molded as described above, resulting in a so-called dual in-line system. are arranged in On the top surface of the setting switch 1, a knob 4 for each switch is slightly protruded from the center hole of the top cover 2b of the case.Sliding the knob 4 in one direction turns on the corresponding switch, and sliding it in the other direction turns it off. It is configured so that

FIG. 2B is a sectional view of the setting switch 1, in which a pair of elongated plate-shaped terminals 3a, 3 are provided on the case body 2a.
A part of the terminal b is molded and held, and one end of each terminal is embedded in the bottom wall of the case body 2a, one plate surface of the end is in close contact with the synthetic resin material, and the other plate surface is in close contact with the synthetic resin material. can come into contact with the contactor 5. Terminals 3a, 3
The other end of b projects outward from the case body and is bent at a substantially right angle near the side wall to form a terminal for solder connection. The contactor 5 is made of an elastic metal body with a symmetrical cross section and a shape (waveform), and both ends of the waveform are defined as the low part of the wave, and at least one of the low parts is connected to the terminal 3a or 3b is elastically contacted with one end. The center part of the contactor 5 is the crest of the wave, and the crest is fixed to the knob 4. The knob 4 is made of a synthetic resin material and has a T-shaped cross section, with a central protrusion serving as an operating section, and is projected upward from the center hole of the upper lid 2b of the case 2. Further, a contact 5 is attached to the inner surface of the bottom plate of the knob 4, and the outer surface is pressed against the inner surface of the upper lid 2b by the action of the contact 5. The edge of the upper lid 2b is fixed to the case body 2a by, for example, an adhesive.

In FIG. 2B, if the operating part of the knob 4 is shifted to the right, one lower part of the contactor 5 will come into contact with the terminal 3b, the other end will come into contact with the terminal 3a, and the other end will come into contact with the terminal 3a.
and 3b are electrically connected. On the other hand, if the operating portion of the knob 4 is shifted to the left, the contact 5 is maintained connected to the terminal 3a, but is disconnected from the terminal 3b. In this way, the contactor 5 and the terminals 3a and 3b constitute one slide switch.

``Problems with the Prior Art'' Setting switches and the like are generally mounted on a printed wiring board together with other components and soldered, and then cleaned to remove dirt on the printed wiring board, such as soldering flux. At this time, the upper surface of the switch is previously sealed with adhesive tape to prevent the cleaning liquid from entering the inside of the switch, and the adhesive tape is peeled off after the cleaning process is completed. However, the degree of adhesion between the terminal 3 and the case body 2a is closely related to the heat shrinkage rate of the material, etc., but even if these factors are considered, it is difficult to maintain complete airtightness, and there is a risk that pinholes may exist. There is. Furthermore, although the terminal 3 is bent after being insert-molded, a slight gap may occur between the terminal and the case body due to the force applied to the case and the deformation of the terminal during this bending process. In such a case, the cleaning liquid may penetrate into the switch through these pinholes and gaps, which may result in poor contact of the switch.

An object of the present invention is to improve the adhesion between an insert-molded terminal and a case to prevent penetration of cleaning liquid.

"Means for Solving Problems" According to this invention, prior to insert molding,
A thermal adhesive layer is wrapped around the circumferential surface of a portion of the terminal embedded in the synthetic resin material.

"Embodiment" According to the terminal holding method for an insert molded component according to the present invention, for example, in the setting switch described in the conventional example, as shown in FIG. Wrap a layer of thermal adhesive with a thickness of, for example, 50 to 150μ around the circumferential surface of, heat it to a temperature of, for example, 100 to 110°C for 1 to 3 seconds,
Attach temporarily. As shown in FIG. 1B, a part of the terminal including the peripheral surface to which the thermal adhesive layer 6 is temporarily bonded is wrapped in a synthetic resin material by insert molding, and the heat of the resin material at that time causes the terminal to be heated. The adhesive layer 6 is heated to, for example, 130 to 180°C for several seconds to several tens of seconds,
The terminal 3 and the case body 2a made of a synthetic resin material are permanently bonded via a thermal adhesive layer 6.

As the thermal adhesive layer 6, an adhesive whose main component is, for example, a nitrile rubber-based material or a nitrile-phenol-based material is suitable.

``Effects of the Invention'' According to the present invention, when the terminal is insert-molded, it is firmly bonded to the synthetic resin material through the thermal adhesive layer, so the adhesion between the terminal and the case body is improved, and compared to the conventional There is no risk of pinholes occurring, and there is no risk of the bond between the terminal and the case body being destroyed and gaps being formed during the bending process of the terminal, as in the case of conventional methods. Cleaning liquid penetrates due to gaps,
The fear of causing a poor contact in the switch is eliminated.

In the explanation so far, this invention has been described using a setting switch as an example, but it is clear that this invention can be widely applied not only to setting switches but also to various types of switches or insert molded terminals of various parts. The effect is huge.

[Brief explanation of drawings]

1A and 1B are a sectional view of a terminal and a sectional view showing essential parts of a setting switch, respectively, for explaining an embodiment of the present invention, and FIGS. 2A and 2B are a perspective view and a sectional view of a conventional setting switch, respectively. FIG.

Claims (1)

[Claims] 1. A terminal holding method for an insert molded component in which a part of the terminal is embedded in the synthetic resin material by insert molding of the synthetic resin material and the terminal is held, wherein, prior to the insert molding, the terminal is A method for holding a terminal of an insert molded part, comprising wrapping a thermal adhesive layer around the circumferential surface of the part of the insert molded part.