JPS6022570Y2 - variable resistor - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a variable resistor, and particularly relates to an improvement in the support structure of a variable resistor using terminals in which a single terminal is molded with resin and the molded body is used as a resistance substrate.

Variable resistors, particularly those referred to as semi-fixed variable resistors, are generally small and are typically mounted on a printed circuit board supported by their terminals.

Among such small-sized semi-fixed variable resistors, this invention is particularly advantageously applied to vertical variable resistors that can be adjusted from the side.

In conventional variable resistors, an alumina substrate, for example, has often been used as the resistance substrate.

The terminals are usually held on such an alumina substrate and led out from the brackets.

As described above, this terminal also provides a support structure for the variable resistor, so its holding form is required to have relatively high strength.

In order to increase this strength, conventional techniques have been applied to the alumina substrate and the terminals.

However, in the next so-called terminal-integrated molded F-type variable resistor proposed in place of the variable resistor containing an alumina substrate as described above, it is difficult to apply the above-mentioned modification, and the terminal Problems regarding the strength of the support structure were encountered.

The structure of the terminal-integrated molded variable resistor will be described with reference to FIGS. 1 to 5.

The resistance substrate 1 has a substantially disk shape and is made of an insulating resin such as epoxy resin.

The resistance board 1 is provided with an insertion hole 2 .

Two fixed side terminals 3 and 4 and one variable side terminal 5 are fixed to the resistance board 1 in a state where they are each partially buried.

The fixed side terminals 3 and 4 are each formed by bending the tip of a band-shaped metal plate made of brass, iron, etc. in two places in opposite directions, and each tip has an exposed portion 6 exposed on the surface of the resistor board 1. , 7.

Further, the variable side terminal 5 is made of a metal plate such as brass or iron, and includes a band-shaped portion and an annular portion continuously extending from the band-shaped portion, and an inner part 11 of this annular portion protrudes in a dish shape. be done.

A part of the band-like part is bent to stand up, and a stopper 8 is formed there.

For the fixed side terminals 3 and 4, the exposed parts 6 and 7 and the terminal parts 9 and 10, and for the variable side terminal 5, the inner part 11 of the annular part, the stopper 8 and the terminal part 1.
Each terminal 3, 4.5 is insert-molded in advance during molding of the resistor board 1 so that the terminal 2 is exposed or protrudes, respectively.

Here, each terminal 3, 4.5 is obtained by later cutting a metal material cut out in a fork shape, that is, a comb shape, from a single metal plate, and when forming the resistance board 1, the above-mentioned The terminal 3°4.5, which is held integrally as a metallic material, is inserted into a mold for the bottom shape of the resistor board 1.

Therefore, the base portions of the terminals 3, 4.5 led out from the resistor board 1 are located on the same plane, which is perpendicular to the end face of the resistor board 1.

After completing the bottom shape of the resistor board 1, each terminal 3,
4.5 is cut.

On one surface of the resistance substrate 1, an arc-shaped resistance film 13 made of, for example, carphone is formed.

The resistive film 13 is applied and baked onto the resistive substrate 1 so as to cover the exposed portions 6 and 7 of the fixed side terminals 3 and 4.

A slider 14 is arranged on the resistive film 13. Slider 14
is approximately disk-shaped, and an arc-shaped slit 15 is formed in a part of its periphery.

The remaining portion in which the arcuate slit 15 is formed is curved downward so as to act as a spring against the resistive film 13.
Further, a downwardly protruding portion is formed, and the contact portion 1 is formed here.
6 is formed.

The entire center of the slider 14 is formed with a dish-shaped downwardly recessed portion, and a square hole is formed in this portion.

Four tongue pieces 17 are formed with each side of this square hole as one side.

Each tongue piece 17 is inserted into the insertion hole 2 of the resistance board 1 and is caulked so as to embrace the inner portion 11 of the annular portion of the variable side terminal 5.

As a result, the slider 14 is rotatably held relative to the resistance substrate 1.

□ In order to prevent such rotation of the slider 14 within a certain range, locking portions 18 and 19 that engage with the stopper 8 are provided.

In the terminal-integrated molded variable resistor shown as an example, the slider 14 is attached to the resistance board 1 during assembly work.
It is easy to assemble by simply caulking it to a part that is in a fixed relationship with the variable terminal (for example, the inner part 11 of the annular part of the variable side terminal), making it easy to assemble and mass produce.

When such a terminal-integrated molded variable resistor is configured as a vertical type, as shown in FIGS. 1 to 3, each terminal 3. 4.5 is led out from one end surface of the resistor substrate 1, and each terminal part 9, 10, 12 is all oriented in the direction in which the slider 14 extends, and each tip part is located at each vertex of the triangle. The variable side terminal 5 is bent at the terminal portion 12.

Then, it is attached to a printed circuit board or the like in the manner shown in FIG.

Referring to FIG. 6, the variable resistor main body 2 including the resistance board etc.
0 is in an upright state, and each terminal 3 facing the same direction,
4.5 is inserted into a predetermined hole of the printed circuit board 21,
In this state, soldering is performed using solder 22.

In this state, when the need for adjustment arises, the slider is rotated with a screwdriver in the direction shown by arrow 23 or arrow 24.

At this time, a force in the direction of arrow 23 or arrow 24 is applied to main body 20 by the driver.

This force acts to tilt the main body 20 using point A or point B as a fulcrum.

Therefore, in such an adjustment operation, if force is applied, the terminals 3.4.5 will bend and the body 20 will tilt.

For example, when a force is applied in the direction of the arrow 23, the terminals 3, 4.5 are bent and the main body 20 is bent in the manner shown in FIG.
will be inclined.

If such inclination of the main body 20 occurs even with a slight force, it becomes a major hindrance to the adjustment operation.

In a terminal-integrated molded variable resistor, each terminal 3, 4.
5, as mentioned above, a metal material cut out in a fork shape, that is, a comb shape, from a single metal plate is inserted into a mold, and the resistor board 1 is integrally molded with this metal material, and then cut. Therefore, each terminal 3. The base portions of the portions 4.5 led out from the resistor substrate 1 are surfaces perpendicular to the end surfaces of the resistor substrate 1, and are located on the same plane.

Therefore, the base portions of the terminals 3, 4.5 led out from the resistor substrate 1 are aligned at the position of point A in FIG. 6.

From this, in particular, terminals 3.4. at point A in FIG.
The bending in No. 5 can be said to be a problem specific to terminal-integrated molded variable resistors.

That being said, to solve this problem,
It is not easy to modify the bases of the lead-out portions of the terminals 3, 4.5 to provide strength, since an alumina substrate is not used in the terminal-integrated molded variable resistor.

Therefore, the main purpose of this invention is to provide a variable resistor structure that can solve the above-mentioned problems peculiar to the integrally molded terminal type.

Simply put, this idea is to form a step on the end surface of the board from which the terminal is led out, and to position the base of the lead-out portion of the variable side terminal on a surface that is more concave than that of the fixed side terminal. The fulcrums corresponding to point A in Fig. 6 are dispersed in the vertical direction to prevent the adjustment force from concentrating on a specific location.

Other objects and features of the invention will become clearer from the detailed description given below with reference to the drawings.

FIG. 8 is a perspective view of an embodiment of this invention.

When FIG. 8 is compared with FIG. 1 of the prior art, the features of this embodiment become clear.

That is, on the end surface 25 of the resistor board 1 from which each terminal 3.4.5 is led out, the base 27 of the lead-out portion of the variable-side terminal 5 is smaller than the base 28.29 of the lead-out portion of the fixed-side terminals 3, 4. A step 26 is formed.

As a result, the base 27 of the lead-out portion of the variable-side terminal 5 and the bases 28 and 29 of the lead-out portions of the fixed-side terminals 3 and 4 are located on mutually different planes parallel to the end surface of the resistor board 1. Become.

Such a modification of the resistance substrate 1 can be easily carried out by simply changing the mold used for molding it.

Further, the variable side terminal 5 extends in a direction along the end surface of the resistance board 1 bent at the base 27, and then is bent at right angles in the opposite direction.

Note that, as a characteristic of the terminal-integrated molded variable resistor, the base 28°29.27 of the lead-out portion of the three terminals 3°4.5 from the resistor board 1 is a surface perpendicular to the end surface of the resistor board 1. As before, they are located on the same two planes.

9 and 10 are side views illustrating the relationship between the point of effort and the fulcrum during adjustment regarding the prior art and this invention.

Now, when an operating force is applied in the direction of arrow 23, the force is applied to main body 20 including the resistance board at point of force 30.

The force applied to this force point 30 is supported by only one fulcrum 31 in the prior art of FIG.

Therefore, as already mentioned, the terminals 3, 4.5 are easily bent at this fulcrum 31.

On the other hand, in the case of this invention shown in FIG. 10, the force applied to the force point 30 is supported by two supporting points 32 and 33 distributed at two upper and lower locations.

The fulcrum 32 corresponds to the position of the base 27 of the lead-out portion of the variable side terminal 5, and the fulcrum 33 corresponds to each base 28, 29 of the lead-out portion of the fixed side terminals 3, 4.

In this way, as shown by the fulcrums 32 and 33, by distributing the fulcrums to multiple locations, the concentration of force on one location is eliminated, and the bends at the bases of the terminals 3, 4, and 5 at 28° and 29.27° are eliminated. The main body 20 can therefore withstand tilting more strongly.

Incidentally, as shown in FIG. 8, ribs 34, 35, 36 may be provided, respectively, in order to further increase the strength of each terminal 3, 4.5 itself.

The ribs 34, 35, 36 can be easily formed by embossing.

These ribs 34, 35, 36 are preferably formed at positions corresponding to point B in FIG.

As described above, according to this invention, on the end face of the resistor board,
A step is formed to recess the base of the lead-out part of the variable-side terminal relative to the base of the lead-out part of the fixed-side terminal, so that the base of the lead-out part of the variable-side terminal and the base of the lead-out part of the fixed-side terminal are different from each other. The base of the lead-out portion of at least one terminal can be located on different planes, and the fulcrum for the adjustment operation force can be distributed.

This prevents the terminal from bending due to the fulcrum concentrating on one location, which is a problem unique to terminal-integrated molded variable resistors.Therefore, the adjustment operation force does not cause the main body to tilt, which improves adjustment operability. An excellent variable resistor can be obtained.

The result of this invention varies depending on the size and shape of the resistor board, etc., but the result is 9×1orIr! It has been demonstrated that a resistive substrate having dimensions of It can withstand a pushing strength of 1 kg (9.8 N) or more.

In addition, as mentioned above, the problems peculiar to terminal-integrated molded variable resistors have been solved, so the necessary three terminals can be A resistor board having all the terminals can be efficiently shaped into a bottom shape, and as a result, a variable resistor with excellent terminal strength can be efficiently manufactured easily.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a prior art variable resistor of interest to this invention. FIG. 2 is a perspective view of FIG. 1 with the slider removed. FIG. 3 is a perspective view of FIG. 2 with the resistive film removed. FIG. 4 is a sectional view of the buried portion of the fixed side terminal. FIG. 5 is a sectional view of the buried portion of the variable side terminal. FIG. 6 is a side view illustrating the force applied during adjustment. FIG. 7 is a side view illustrating a drawback of the variable resistor shown in FIG. 6. FIG. 8 is a perspective view of an embodiment of this invention. FIGS. 9 and 10 are side views illustrating the relationship between emphasis and inclination during adjustment in the prior art and this invention. In the figure, 1 is a resistance board, 3 and 4 are fixed side terminals, 5 is a variable side terminal, 6 and 7 are exposed parts, 13 is a resistance film, 14 is a slider, 16 is a contact part, and 20 is a variable resistor In the main body, 25 is an end surface, 26 is a step, and 27, 28, and 29 are bases of terminal lead-out portions.

Claims (1)

[Scope of claim for utility model registration] Two fixed side terminals, one variable side terminal located between the two fixed side terminals, and a part of one end of each fixed side terminal. The two fixed side terminals and one variable side terminal are integrally molded including one end of each in a state exposed to the surface, and all three terminals are led out from one end surface and attached to the one end surface. a substrate in which the bases of the lead-out portions of the three terminals are located on the same orthogonal plane; a resistor formed on the surface of the substrate so as to be electrically connected at both ends to the exposed portion of each fixed side terminal; A resistor is electrically connected to the side terminal, and a slider is electrically connected to the variable side terminal and has a contact portion that slides on the resistor, and the variable side terminal is bent, thereby forming three terminals. In the variable resistor, the tip of each lead-out part is located at each vertex of a triangle, and the base of the lead-out part of the variable side terminal is attached to the end face of the board from which three terminals are led out. A step is formed to be recessed compared to the base of the lead-out portion of the fixed-side terminal, so that the base of the lead-out portion of the variable-side terminal and the base of the lead-out portion of each fixed-side terminal are on mutually different planes parallel to the end surface. , wherein the variable side terminal is bent at the base of the lead-out portion, extends in a direction along the end surface of the substrate, and then bent at right angles in the opposite direction.