JPH04279006A - Variable resistor - Google Patents

Abstract

PURPOSE:To eliminate the need of connecting lead terminals so as to reduce the cost of a variable resistor by making a mold case unnecessary so as to eliminate the need of an insert mold forming process and, at the same time, making the ceramic substrate of the resistor to crop out. CONSTITUTION:This variable resistor is used for surface mounting and has a sealed structure formed by using an O-ring 2 made of an elastic insulating material between a rotator 1 and insulating substrate (alumina substrate) 4 on which a resistor is formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable resistor, and more particularly to the structure of a surface-mounted variable resistor in which a ring-shaped seal made of an elastic insulator is inserted between a rotor and an insulating substrate to seal the rotor.

0002

[Prior Art] Conventionally, a variable resistor for surface mounting has an O-ring 2 made of an elastic insulator such as silicone between the outer periphery of a rotor 1, a can case 5, and a mold case 8, as shown in FIG. It was loaded and sealed.

That is, the slider 3 is arranged at a position that bridges the annular resistor formed on the alumina substrate 4 and the circular conductor disposed at the center. This slider 3 is drilled and fixed by heat caulking to a part of the inner bottom surface of the rotor 1 housed in the can case 5 so as to be inscribed therein, and maintains an appropriate contact pressure for the low antibody and the conductor. .

[0004] Here, an O-ring 2 made of an elastic insulator such as silicone rubber is mounted on the interface between the rotor 1, the can case 5, and the mold case 8 to seal it from the outside air, and is press-fitted during assembly to seal it from the outside atmosphere. It's sealed.

[0005] A lead terminal 7 for taking out the terminal portion of the resistor to the outside is connected to the alumina substrate 4 to the conductor by thermocompression bonding or the like, and only the necessary portions of the alumina substrate 4 and the lead terminal 7 are exposed. A molded case 8 was formed by insert molding to obtain a sealed surface-mounted variable resistor.

[0006]

[Problems to be Solved by the Invention] In the sealed structure of the conventional variable resistor described above, as shown in FIG. (1) Since the rotor is inscribed in the molded case, an insert molding process is required.

(2) Since the ceramic substrate is covered with a molded case, it is necessary to draw out the lead terminals to the outside. There were some problems.

The object of the present invention is to eliminate the conventional drawbacks, eliminate the need for a molded case, eliminate the need for an insert molding process, and eliminate the need for connecting lead terminals, resulting in a reduction in the number of parts and low cost. The object of the present invention is to provide a surface-mounted variable resistor that can achieve

[0009]

[Means for Solving the Problems] The variable resistor of the present invention includes an insulating substrate, a low antibody disposed in a ring on the insulating substrate, and a low antibody disposed on the insulating substrate at the center of the ring of the low antibody. a conductor disposed at a distance from the low antibody; a slider that bridges and slides the low antibody of the conductor; a rotor that fixes the slider; It includes an exterior case that houses an insulating substrate, and a ring-shaped seal made of an elastic insulator that seals between the rotor and the insulating substrate described above.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a rear view, a top view, a front view, a bottom view, a right side view, and a sectional view of a first embodiment of the present invention.

In the first embodiment, as shown in FIG. 1, an O-ring 2 is elastically mounted between a rotor 1 and an alumina substrate 4 to seal the rotor 1 and the alumina substrate 4. That is, the slider 3 is arranged at a position that bridges the annular low antibody formed on the alumina substrate 4 and the circular conductor disposed at the center. This slider 3 is drilled and fixed by heat caulking to a part of the inner bottom of the rotor 1 which is held so as to be inscribed in the can case 5, and maintains an appropriate contact pressure to the low antibody and the conductor.

At the interface between the rotor 1 and the alumina substrate 4, an O-ring 2 made of an elastic insulator such as silicone rubber is elastically mounted in the O-ring internal groove 1a of the rotor 1 in order to seal the outside air. At the same time, the tip of the can case 5 is bent and pressed against the back surface of the alumina substrate 4 to seal it from the outside atmosphere.

[0013] On the alumina substrate 4, a conductor 6 that can be soldered to take out the low-antibody terminal portion is printed and extended to the back side of the alumina substrate 4, and has an outer diameter of 4 mm square and a rated power of 0.2.
We have obtained a sealed type variable resistor for surface mounting with 5W, resistance value deviation of ±10%, and contact resistance change of 5% or less.

FIG. 2 shows a rear view, a top view, a front view, a bottom view, a right side view, and a sectional view of a second embodiment of the present invention. The second embodiment is structurally the same as the first embodiment as shown in FIG.
A similar variable resistor can be obtained by loading ring 2.

[0015]

[Effects of the Invention] As explained above, in the present invention, a ring-shaped seal made of an elastic insulator is inserted between the rotor and the insulating substrate, so (1) a molded case is not required. This eliminates the need for an insert molding process.

(2) Since the ceramic substrate is exposed to the outside, there is no need to connect lead terminals.

(3) Compared to conventional variable resistors, two parts, the molded case and lead terminals, can be eliminated, making it possible to reduce costs. It has this effect.

[Brief explanation of the drawing]

FIG. 1 is a rear view, a top view, a front view, a bottom view, a right side view, and a sectional view of a first embodiment of the present invention.

FIG. 2 is a rear view, a top view, a front view, a bottom view, a right side view, and a sectional view of a second embodiment of the present invention.

FIG. 3 is a rear view, a top view, a front view, a bottom view, a right side view, and a sectional view of an example of a conventional variable resistor.

[Explanation of symbols]

1 Rotor 1a O-ring internal groove 2 O-ring 3 Slider 4 Alumina substrate 4a O-ring internal groove 5 Can case 6 Conductor 7 Lead terminal 8 Mold case

Claims (1)

[Claims] 1. An insulating substrate, a low antibody disposed in a ring on the insulating substrate, and a low antibody disposed on the insulating substrate at the center of the ring of the low antibody at a distance from the resistor. a conductor,
A variable resistor comprising a slider that bridges the conductor and the low antibody and slides, a rotor that fixes the slider to a bottom surface, and an exterior case that stores the rotor and the insulating substrate. 2. A variable resistor characterized in that a ring-shaped seal made of an elastic insulator is inserted between the rotor and the insulating substrate.