JPH088164B2 - Variable resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a variable resistor in which a slider rotates and slides on a resistor to change a resistance value.

<Prior Art> Conventionally, as a variable resistor for high voltage, the one shown in FIG. 4 has been known. The variable resistor 20 has a rotating shaft portion 2, a case 3, and an insulating substrate 4. The rotary shaft portion 2 is composed of a rotary shaft 5 and a flange 6 provided at the shaft end of the rotary shaft 5, and a slider 7 extending downward is provided at the lower end of the flange 6. The slider 7 is made of an elastic body such as a leaf spring. The lower end of the case 3 is open. A rotating shaft member storage recess 8 is formed on the upper end side of the case 3, and an insertion hole 9 is formed in the center of the storage recess 8 so as to communicate with the inside and outside of the case.
The insulating substrate 4 has a resistance pattern 10 at a predetermined position on its surface.
Are formed by printing or the like.

The rotating shaft portion 2 is rotatably attached to the case 3. That is, the rotary shaft 5 is inserted through the insertion hole 9 in a state where the flange 6 is housed in the housing recess 8. Insulating substrate 4
Is attached to the open end of the case 3 with an adhesive or the like with the surface inside the case 3, and the resistance pattern 10 is in pressure contact with the slider 7.

The variable resistor 20 is configured such that the rotary shaft 2 is rotated from the outside of the case 3 so that the slider 7 slides on the resistance pattern 10 to change the resistance value.
Reference numeral 11 is a grease provided in the insertion hole 9 as needed.

<Problems to be Solved by the Invention> By the way, in the variable resistor 20, it is necessary to obtain a predetermined rotational torque in the rotary shaft portion 2. Therefore, conventionally, the rotational torque is obtained by the elastic repulsive force due to the spring pressure when the slider 7 is pressed against the insulating substrate 4. Therefore, when it is necessary to obtain a large rotational torque, the slider 7 has a resistance pattern larger than necessary.
When the sliding contact of the slider 7 was repeated, the resistance pattern 10 was scraped off the surface, which caused electrical noise.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a variable resistor that can reduce scraping off of a resistance pattern that causes electrical noise.

<Means for Solving the Problems> The variable resistor of the present invention has a case and
The rotary shaft is inserted into the insertion hole of the case, the flange integral with the rotary shaft is housed in the housing recess of the case, and the slider is attached to the lower end surface of the flange, and the rotary shaft is attached to the open lower end of the case. And an insulating substrate having a resistance pattern formed on the surface thereof, and the upper end surface of the flange is configured such that the slider is elastically pressure-contacted to the resistance pattern on the surface of the insulating substrate. A variable resistor that is pressed axially upwardly and is in contact with the upper inner wall of the storage recess, wherein an elastic body that forms elastic force in the radial direction is formed on the side surface of the flange of the rotating shaft portion. The flange of the rotary shaft portion is pressed in the radial direction by the elastic body elastically abutting the peripheral wall of the case.

<Operation> According to the above configuration, the upper end surface of the flange of the rotating shaft portion is pressed against and contacts the upper inner wall of the housing recess of the case by the reaction force of the slider elastically contacting the resistance pattern on the insulating substrate. Further, the side surface of the flange is pressed from the side inner wall of the case through the elastic body by the reaction force of the elastic body coming into contact with the peripheral wall of the case. Not only the friction between the housing flange and the housing recess, but also the friction between the elastic body and the peripheral wall of the case.

As a result, the rotational torque of the rotating shaft portion can be obtained mainly by the friction between the elastic body and the case peripheral wall. By reducing the friction of the end face contacting the inner wall of the case upper part, the pressure contact force of the slider to the resistance pattern is reduced, and the slider rotates with respect to the resistance pattern to obtain the rotation torque of the rotating shaft. As a result of eliminating the need to make contact more than necessary to perform the function of applying torque, the resistance pattern is not scraped off by the slider, and the electrical noise that causes this is greatly reduced. It

<Example> Hereinafter, the present invention will be described in detail based on an example shown in the drawings. FIG. 1 is a vertical sectional view of a high voltage variable resistor according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II thereof.

The structure of the variable resistor 1 is basically the same as that of the conventional example, and the same or similar members and parts are designated by the same reference numerals, and detailed description thereof will be omitted.

The characteristic structure of this embodiment is that the spring member 12 (elastic body) is integrally provided on the side surface of the flange 6 of the rotary shaft portion 2. The rotating shaft portion 2 is formed as an integrally molded product of a resin such as modified PPO (polyphenylene oxide) or PBT (polybutylene terephthalate). Therefore, the spring member 12 made of the same resin as the rotating shaft portion 2 is attached to the rotating shaft portion 2 by integral molding. In the case of this embodiment, the spring member 12 is formed at a predetermined position on the peripheral surface of the flange 6, and its free end side 12
a extends outward in the radial direction of the flange 6 (radial direction of the rotary shaft portion). In addition, the distance between the tip of the spring member free end 12a and the shaft center of the rotary shaft portion 2 is determined by the accommodation recess 8
It is set slightly larger than the inner radius of the.

In the figure, reference numeral 13 is one projection for limiting the rotation range provided on the side surface of the flange 6. The fixed end side 12b of the spring member 12 also serves as the other projection for limiting the rotation range.

The rotary shaft portion 2 is rotatably attached to the case 3 by inserting the rotary shaft 5 from the inside of the case 3 into the insertion hole 9 as in the conventional example. At that time, the flange 6 is housed in the housing recess 8. In this case, since the slider 7 is elastically pressed against the resistance pattern 10 on the surface of the insulating substrate 4, the upper end surface of the flange 6 is axially above the upper inner wall of the housing recess 8 of the case 3. Is pressed into contact with. Further, at this time, the spring material 12 provided on the side surface of the flange 6 is elastically deformed and elastically abuts the circumferential habit 8a of the storage recess 8 in the radial direction. This elastic contact force forms the rotational torque of the rotary shaft portion 2. Then, the insulating substrate 4 is attached to the case 3 with an adhesive or the like so as to close the open end of the case 3.
When the insulating substrate 4 is attached to the case 3, the insulating substrate 4
The upper resistance pattern 10 comes into pressure contact with the slider 7 provided at the lower end of the flange 6 as in the conventional example. However, the rotating shaft portion 2 is adapted to obtain a sufficient rotating torque by the spring member 12. Therefore, it is not necessary to press the slider 7 with an unnecessarily large pressure contact force, and the spring pressure of the slider 7 is set in consideration of this point.

In the above embodiment, the spring member 12 is cantilevered by the flange 6, but as shown in FIG. 3, both ends of the spring member 12 may be supported by the flange 6. Good.

Further, in the above-mentioned embodiment, it is carried out in the high voltage variable resistor, but the present invention is not limited to this, and it can be carried out if the slider is a type of variable resistor in which the slider rotates and slides on the resistor. it can.

Further, in the above-described embodiment, the elastic body is the integrally formed spring member 12 made of the same resin as the rotary shaft portion 2, but the elastic body is formed by another member such as a leaf spring to form the rotary shaft portion. It may be attached, and an elastic body may be formed on the peripheral surface of the rotating shaft 5 other than the flange 6.

<Effects of the Invention> As described above, according to the present invention, the upper end surface of the flange has an upper portion of the storage recess of the case because the slider is elastically pressed against the resistance pattern on the surface of the insulating substrate. Friction is obtained by being pressed axially upward and in contact with the inner wall, and on the side surface of the flange of the rotary shaft portion, an elastic body that forms elastic force in the radial direction is formed. The flange of the rotating shaft is also frictionally obtained by being pressed in the radial direction by the elastic body elastically abutting the peripheral wall of the case, which causes the rotating torque of the rotating shaft to rotate. Not only the friction between the flange of the shaft portion and the storage recess but also the friction between the elastic body and the case peripheral habit is obtained. Therefore, the rotational torque is mainly obtained by the friction between the elastic body and the case peripheral wall. Profit By doing so, it becomes unnecessary for the slider to press the upper end face of the flange against the inner wall of the upper part of the case housing recess in order to obtain the rotation torque, and thus the slider has a function of giving the rotation torque more than necessary. It is no longer necessary to fulfill it, and it is no longer pressed against the resistance pattern more than necessary. Therefore, it suffices for the slider to be pressed against the resistor with an elastic contact force necessary for connection, and scraping of the resistor due to sliding of the slider is reduced. Therefore, a large rotational torque can be applied to the rotary shaft portion without causing the inconvenience of electrical noise.

[Brief description of drawings]

1 and 2 relate to an embodiment of the present invention. FIG. 1 is a vertical sectional view and FIG. 2 is a sectional view taken along line II-II of FIG.
FIG. 3 is a vertical sectional view of another embodiment. FIG. 4 is a vertical sectional view of a conventional example. 1 …… Variable resistor 2 …… Rotating shaft 3 …… Case 7 …… Slider 8a …… Storing recess peripheral wall (case inner wall) 10 …… Resistance pattern 12 …… Spring member (elastic body)

Claims (1)

[Claims] 1. A case and a rotary shaft portion, wherein a rotary shaft is inserted into a through hole of the case, a flange integral with the rotary shaft is housed in a housing recess of the case, and a slider is attached to a lower end surface of the flange. And an insulating substrate attached to the open lower end of the case and having a resistance pattern formed on the surface thereof, and the upper end surface of the flange is such that the slider is elastically pressed against the resistance pattern on the surface of the insulating substrate. By
A variable resistor that is pressed axially upwardly and is in contact with the upper inner wall of the storage recess of the case, wherein an elastic body that forms an elastic force in the radial direction is provided on a side surface of the flange of the rotary shaft portion. The variable resistor is formed, and the flange of the rotary shaft portion is pressed in the radial direction by the elastic body elastically abutting against the peripheral wall of the case.