JPS6261302A - Manufacturing stationary side member for electric part - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Use of invention ￥f] The present invention is a rotary type or sliding type variable resistor.

Related to a method for manufacturing a fixed side member in an electrical component such as a rotary switch, which includes a fixed side member formed with a wiring pattern such as a resistor, and a movable side member having a slider that slides in contact with the fixed side member. It is something.

[Prior Art] As an electrical component, for example, a rotary variable resistor is provided with a slider slidably in contact with a resistor formed in an arc shape, and the slider contacts the resistor in the diagonal direction. The structure is such that the resistance value can be adjusted by displacing the contact position. Here, the resistor is usually formed on a board using printing or other means, and lead terminals connected to both ends of the resistor are attached to this board, and the board and terminals are housed in an insulating case. The slider forms a fixed side member, and the slider is attached to an adjustment knob for externally operating the slider to form a movable side member, and this movable side member is attached to the above-mentioned fixed side member. By rotatably assembling them, a rotary variable resistor is formed.

Therefore, when manufacturing the above-mentioned stationary side member, -
A substrate with a resistive layer formed on the side surface is fixed to the terminal, this substrate is placed in a mold cavity, and resin is injected into the mold, so that the substrate and terminal forming body are assembled into an insulating case. There is. In order to prevent the resin from adhering to the resistance layer formed on the surface of the substrate, a core is provided in the cavity of the mold so as to face it, and the front end surface of the core is made to cover the surface of the substrate. ing.

Incidentally, the core is usually fixedly provided, so the dimensions of the substrate that comes into contact with the core must be strictly controlled, but due to manufacturing errors and other reasons, the substrates do not necessarily have exactly the same thickness. Therefore, in order to adjust the variation in the thickness of the substrate, a protrusion is provided on the mold facing the core, and the distance between this protrusion and the tip surface of the core is adjusted to the minimum thickness of the substrate. When a substrate exceeding this minimum thickness is introduced into the mold, the thickness error is adjusted by making the substrate bite into the projection.

Here, there is no particular problem if the substrate has some elasticity, such as phenol resin, and there is no risk of it being damaged even if it is bitten into the protrusion. From a point of view, for example, printing metal glazed resistors or conductors on a ceramic substrate,
It is preferable to use a fired ceramic material, but since such ceramic material is a hard and brittle member, once a substrate is formed from a ceramic material, when it is introduced into a mold and an insulating case is assembled, the above-mentioned protrusions will cause If variations in thickness are absorbed, there are disadvantages such as cracks and damage to the substrate.

[Object of the Invention] The present invention has been made in view of the above points, and provides a method that allows the board to be smoothly and reliably assembled into an insulating case even if the board is made of a fragile material such as a ceramic material. The present invention provides a method for manufacturing a fixed side member of an electrical component.

[Summary of the Invention] In order to achieve the above-mentioned object, the method of the present invention provides the following steps: The board is placed in a cavity in a mold with its wiring pattern forming surface covered by a core, and by supplying synthetic resin into the cavity, the board and terminal are assembled to form an insulating case. During this molding, resin is injected into the cavity of the mold with a predetermined pressure toward the surface of the substrate that opposes the contact surface with the core, and the resin injection pressure causes the It is characterized in that the substrate and the core are brought into close contact.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In this embodiment, a method for manufacturing a fixed side member in a rotary variable resistor will be described as an example of an electrical component.

The rotary variable resistor has a structure as shown in FIG. That is, 1 in Figure 1 is a cylindrical insulating case with a bottom, and a substrate 2 made of a ceramic material is installed on the bottom wall inside the insulating case 1, and a metal glaze is applied as a wiring pattern on the substrate 2. The resistance layer 3 is formed in an arc shape. Terminals 4.5 are connected to both ends of the resistance layer 3, and the tips of each terminal 4.5 are led out from the insulating case l. These insulation cases 1. A fixed side member is formed by the substrate 2 provided with the resistance layer 3 and the terminals 4 and 5.

One end 6a of a slider 6 made of a conductive spring material is slidably in contact with the resistance layer 3 and JH. This slider 6 is a first adjustment knob 7 rotatably attached to the insulating case l.
The attachment also engages with a second adjustment knob 8 extending through the bottom of the insulating case 1 on the opposite side.

These first and second adjustment knobs 7 and 8 have operating grooves that are rotatably operated by a jig such as a screwdriver. a, 8a
are formed respectively. Also, the second adjustment knob 8
A terminal 9 connected to the J'fff mover 6 protrudes from the side. These sliders 6. 1st. Second adjustment knob 7, 8
and the terminal 9 constitute a movable member.

The rotary variable resistor constructed as described above is used with its terminals 4, 5.9 attached to the printed wiring board 10, and the first and second adjustment knobs 7
．． 8 allows adjustment to be made to obtain a desired resistance value.

Next, a method for manufacturing the fixed side member of this rotary variable resistor will be explained based on FIGS. 1 and 2.

First, in order to form the terminals 4.5, the hoop material 20 made of a band-shaped metal is pressed, so that the installation part 21 of the board 2 and the installation part 21 are formed as shown in FIG. 1(A).
These installation parts 21 . A terminal forming body 23 is formed by providing a pair of left and right leg portions 22. Here, the leg portions 22 in each pair constitute terminals 4.5 of the fixed side member.

Next, as shown in FIG. 1(b), the substrate 2 with the resistive layer 3 formed on the surface by means such as a printed wiring pattern is attached to the installation portion 21 of the terminal forming body 23 formed as described above. The side surface on the side where the resistance layer 3 is formed is brought into contact with the installation part 21, and the resistance layer 3 and the terminal formation body 23 are installed in an electrically connected state, and the substrate 2 is bonded to the installation part 21. Attach by means such as soldering or eyelets.

Thereafter, as shown in FIG. 1(c), the insulating case 7 is molded by outsert molding with the terminal forming body 23 assembled together with the board 2.

Finally, as shown in FIG. 1(d), the insulating case 7, the substrate 2, and the terminal forming body 23 constituting the fixed side member leave the legs 22 forming the terminals 4.5 on the insulating case 7 side. The fixed side member is manufactured by cutting the hoop material 20 and bending the leg portions 22.

Here, the above-mentioned molding process is performed using a mold 30 shown in FIG. That is, the mold 30 has a pair of mold pieces 3
1.Cavity 3 between by joining 32
3 is formed, and the substrate 2 is placed in the cavity 33, and the legs 22 of the terminal forming body 23 are held between the mold pieces 31 and 32, and the substrate 2 is placed in a positioned state in the cavity 34. let Then, the resistive layer 3 on the surface of the substrate 2 is covered with the tip end surface of the core 34 provided in the mold 30 so as to face into the cavity 33 from the mold piece 31 side, so that the resin does not adhere to this surface. Make it.

Here, the resin is injected into the cavity 34 of the mold 30 by applying a predetermined pressure toward the surface of the substrate 2 opposite to the surface that contacts the core 34, as indicated by the arrow in FIG. The resin injection pressure presses the substrate 2 toward the core 34 to bring the substrate 2 and the core 34 into close contact. For this reason, the substrate 2 and the core 34 are in close contact with each other in a good condition regardless of the thickness of the substrate 2.
Even if the plate thickness varies due to manufacturing errors or the like, there is no risk of resin adhering to the resistance layer 3 formed on the surface of the substrate 2 during molding of the insulating case 1.

Therefore, even if the board 2 is made of a hard and brittle material such as a ceramic material, the board 2 will not be cracked or damaged when assembled to the insulating case 1. Can be assembled smoothly.

In the above-described embodiments, a rotary variable resistor has been described, but it may also be configured as a sliding type variable resistor, a rotary switch, or other similar electrical components. Further, the specific structure of the variable resistor is not limited to that shown in FIG. 5, and any structure, such as one without the second adjustment knob 9, can be used. Furthermore, the leg portions 22 of the terminal forming body 23 may be fixed to the surface of the core 34 on the opposite side to the contact side on which the resin pressure is applied.

[Effects of the Invention] As detailed above, the method of the present invention utilizes the pressure of the resin injected into the mold, and uses this resin pressure to bring the substrate into close contact with the core.

Even if there are variations in board thickness due to board manufacturing errors, the board can be assembled into an insulating case without resin adhering to the wiring pattern formed on the surface of the board, and the hard yet fragile parts can be assembled. Even if the substrate is made of a solid ceramic material, its insulation and assembly to the base can be easily and smoothly performed.

[Brief explanation of drawings]

Figures 1 (a), (b), (c), and (d) are explanatory diagrams showing the manufacturing process of the present invention, Figure 2 is an explanatory diagram of the configuration of the molding process, and Figure 3 is an explanatory diagram of the rotary variable resistor. FIG. 1: Insulating case, 3: Resistance layer, 4, 5: Terminal, 20: Hoop material, 21: Installation part, 22: Leg part, 23: Terminal forming body, 30: Mold, 33: Cavity, 34: Core. Figure 2 Figure 3' Figure (C2 22C5)

Claims (1)

[Claims] A state in which a substrate with a wiring pattern formed on one side is fixed to a terminal forming body made of a metal plate on the other side, and the substrate is placed in a cavity in a mold with the wiring pattern formed surface covered by a core. In the method for manufacturing a fixed side member of an electrical component, the electric component is installed in the mold cavity, and a synthetic resin is supplied into the cavity to assemble the board and the terminal to form an insulating case. By injecting resin with a predetermined pressure toward the surface of the substrate that opposes the contact surface with the core,
A method for manufacturing a fixed side member of an electrical component, characterized in that the resin injection pressure brings the substrate and core into close contact.