JPS5956704A - Method of producing variable resistor - 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 Field of the Invention The present invention relates to a method of manufacturing a variable resistor used in general electronic equipment.

The configuration of the conventional example and its problems Figure 1 shows an insulating case (1), a rotating shaft (2+) passing through the bottom of the case, and a sliding contact (3) provided on the rotating shaft (21).
and.

This is an example of a conventional variable resistor consisting of an insulating substrate (4) having a resistor for variable resistance. Conventional variable resistors, especially those for commercial pressure, maintain a withstand voltage between electrodes and prevent moisture and foreign matter from entering the inside. The internal electrode part is coated with epoxy resin (5) to prevent it from penetrating.
It is sealed with. Rubber rings or seals (0) were essential to prevent liquid epoxy resin from entering the parts of the variable resistor due to the presence of cattle. In addition, with the variable resistor built into the flyback transformer, the problem of voltage resistance between the electrodes and ingress of moisture and foreign matter can be solved by the sealing IL resin of the flyback transformer, but due to the expansion and contraction of the sealing resin. It was necessary to seal the resistor with a resin that had a buffering effect so that the resistor would not be damaged by strain1, so rubber rings and sealing materials were also essential.

If this sealing material is incomplete, the resin may flow into the mechanism or bubbles may form in the resin, resulting in product defects.
This leads to a decrease in the sharpness of the apex, and the work itself is done manually, which causes an increase in price. Purpose of the Invention 1 aims at providing a variable resistor at a low cost by solving the above-mentioned problems, reducing the number of parts, and using a construction method suitable for automation.

Structure of the Invention In the present invention, a rotating shaft equipped with a sliding contact is inserted into a bottom through hole of an insulating case that is open at one end and has a through hole at the bottom, and an insulating substrate having a variable resistance resistor on one surface. is fitted into the opening of the insulating case, and the insulating substrate and the insulating case are integrally molded with thermoplastic resin to fix the insulating substrate to the insulating case and sealing the opening of the insulating case.

DESCRIPTION OF EMBODIMENTS FIG. 2 is a side sectional view of a variable resistor made according to the present invention;
FIG. 3 is a plan view of the insulating substrate. In Figure 2 (1
) is an insulating case with an opening at one end, a through hole (1a) is provided in the center of the bottom, and a step (1c) protruding toward the inner surface is provided near the opening (1). There is. (2)
is a turning shaft made of an insulating material inserted into the hole (1a) of the case (1) from the hollow part (1b) side, and the contact (3) is attached to one end of the shaft, and the contactor (3) is attached to one end of the shaft. There is a rotatable handle at the bottom. (4) is the case (1)
) The insulating substrate is attached to the opening of the case (1) with its peripheral edge in contact with the step (1c) of the case (1).

(tll) facing the hollow part (1b) of this insulating substrate (4)
An electrode (7) is provided at the center of the surface of the electrode (σ) as shown in the figure, and a horseshoe-shaped resistor (8) is provided around it concentrically with the electrode (7). The contactor (3) slides on the resistor (8) as the rotating shaft (2) rotates and connects the conductor (8a) at both ends of the resistor (8).
IW is connected to either one of the external terminals (not shown) connected to VC and the extension (7a) of the electrode (7).
This is to change the resistance value of 11-1 with a child (not shown).

As shown in Figure 2, this insulating substrate (4) is made of thermoplastic resin (9) that is directly injection molded from a molding machine.
) is molded in close contact with the resin (9) and the insulating substrate (
4) is fixed to the case (1) and the opening of the case (1) is sealed.

During this molding, a pre-molded resin plate 00 is stacked on the back side of the insulating substrate (4) as shown in FIG. is integrally molded with thermoplastic resin (9) to form an insulating substrate (,
i) Fix the IJ VC and the case (l)
It is also possible to seal λotaa=a+h.

During manufacturing, in steps 1 to 1, as shown in Figure 5, an insulating case (
1], insert the rotating shaft (2) into the insulating substrate (4), fit the insulating substrate into the step (1c) of the opening of the insulating case, and then insert the rotating shaft (2) into the mold (]]). Insert it into the recess, close the mold, and perform molding. According to the manufacturing method of the present invention, there is no need for a rubber ring or a sealant, and a molding machine is used instead of the work that must be done manually such as inserting a rubber ring or applying a sealant. It is possible to automate many processes, and a major improvement in the number of processes can be achieved.

Furthermore, in the case of a flyback transformer integrated with the flyback transformer, the injection of epoxy resin can be omitted since the molded layer acts as a buffer. Thus, according to the present invention,
The number of parts and steps are reduced, automatic assembly is possible, and the price of the variable resistor can be reduced.

[Brief explanation of the drawing]

Figure 1 is a cross-section diagram of an example of a variable resistor manufactured using the conventional method.
Fig. 2 is a side cross-sectional view of a variable resistor produced by the method of the present invention, Fig. 2 is a bottom view of an insulating substrate constituting the variable resistor, and Fig. 4 is another example of a variable resistor produced by the method of the present invention. 41) I sectional view and FIG. 5 are perspective views showing a part of the manufacturing process of the present invention. (11.--Insulation case, (21.-.Rotating shaft, (
3)...Sliding contact, (4)...Insulating substrate, (
5)...Epoxy resin, (6)...Sealing material, (
7)... Electrode, (8)... Resistor, (9)...
Thermoplastic resin, 00...Resin plate, a])...Molding mold ○ Name of agent Patent attorney Etsuji Yoshizaki Figure 5

Claims (1)

[Claims] 1. On the other hand, σ) an insulating substrate on which a variable resistance resistor is formed, a rotating shaft having a sliding contact at one end, and an opening at one end and a through hole at the bottom. In a variable resistor consisting of an insulating case, a rotating shaft is inserted into the through hole of the insulating case, a resistor is brought into contact with a sliding contact provided on the rotating shaft, and the insulating substrate is fitted into the opening of the insulating case. A method of manufacturing a variable resistor is characterized in that the insulating substrate and the insulating case are integrally fixedly molded with a thermosolizable/rho resin, and the opening is sealed. 2. In the variable resistor, insert the rotating shaft into the through hole of the insulating case, bring the resistor into contact with the sliding contact provided on the rotating shaft, fit the insulating substrate into the opening of the insulating case, and A patent claim characterized in that a pre-molded resin plate is placed on an insulating substrate, and the resin plate, insulating substrate, and insulating case are integrally fixed and molded with thermoplastic resin to seal the opening. A method for manufacturing a variable resistor according to item 1.