JPH07101642B2 - Variable resistor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable resistor in which a slider rotatively slides on a resistor to change its resistance value.

<Prior Art> As a variable resistor of this type, a high voltage variable resistor shown in FIG. 5 has been conventionally known.

The high-voltage variable resistor 20 has a case 2, an insulating substrate 3, a rotary shaft portion 4, a slider 5, and a thermosetting resin layer S. The case 2 is open at both upper and lower ends. The upper end opening 2a of the case 2 forms a rotary shaft portion insertion hole.
A rotary shaft accommodating recess 7 is formed inside the case 2 so as to be continuous with the upper end opening 2a. And the lower end opening of the case 2
2b is formed on the entire lower surface of the case 2. The insulating substrate 3 is arranged inside the case 2 from the lower end opening 2b side of the case 2, and a resistance pattern 8 is formed by printing or the like at a predetermined position on the surface 3a thereof. The rotary shaft portion 4 includes a rotary shaft 9 and
It comprises a flange 10 provided at the shaft end of the rotary shaft 9. The slider 5 is composed of a leaf spring or the like, is attached to the lower end of the flange 10 and extends downward. The thermosetting resin layer S is provided on the entire outer surface 3c of the case of the insulating substrate 3.

That is, the insulating substrate 3 is fixed to the case 2 with the surface 3a thereof being inside and the side portion 3b thereof being brought into contact with the case 2 via the adhesive A made of a thermosetting resin. The rotary shaft 9 is inserted into the insertion hole 6, the flange 10 is housed in the housing recess 7, and the rotary shaft portion 4 is rotatably attached to the case 2. The lower end of the flange 10 housed in the case 2 faces the insulating substrate surface 3a, and the slider 5
Are pressed against the resistance pattern 8. The insulating substrate 3 is
The case outer surface 3C side is covered with the thermosetting resin layer S.

Reference numeral 11 is grease provided in the upper end opening 2a as needed.

By the way, in this type of variable resistor, it is necessary to obtain a rotating torque in the rotating shaft portion 4. Therefore, in the high voltage variable resistor 20 described above, the rotational torque is obtained by the elastic contact force of the slider 5 against the insulating substrate 3 due to the spring pressure.

<Problems to be Solved by the Invention> However, in such a structure, when it is necessary to obtain a large rotational torque, the slider 5 is pressed against the surface of the resistance pattern 8 more than necessary, and therefore the resistance is increased. The surface of the pattern 8 is easily scraped off by the sliding of the slider 5, which causes the generation of electrical noise.

In order to eliminate this inconvenience, the high voltage variable resistor shown in FIGS. 6 to 7 can be considered. This is the rotary shaft 4
An elastic body is provided on the above, and the rotational torque is obtained by this elastic body.

That is, this high-voltage variable resistor 30 has a peripheral surface of the flange 10.
An elastic body 12 is attached to 10a by integral molding. The elastic body 12 extends outward from the peripheral surface of the flange 10 and forms an elastic force in the radial direction of the rotary shaft portion 4. When the rotating shaft portion 4 provided with the elastic body 12 is attached to the case 2, the elastic body 12 elastically abuts the peripheral wall 7a of the storage recess 7,
The rotating shaft portion 4 obtains a rotating torque by this elastic repulsive force. Therefore, it is not necessary to press the slider 5 on the resistance pattern 8 excessively.
It reduces the scraping off.

However, in the variable resistor 30, the elastic body 12 is
However, there is a disadvantage that the elastic force is lost and a sufficient rotation torque cannot be obtained. This is because it is necessary to heat the adhesive A and the resin S to cure them, and the applied heat is transmitted to the elastic body 12. The elastic body 12 is
The rotary shaft portion 4 is formed of the same resin as that of the rotary shaft portion 4 by integral molding, and is elastically deformed by coming into contact with the storage recess peripheral wall 7a. Therefore, the elastic body 12 undergoes thermal deformation due to heating, and it becomes impossible to form an elastic force on the case 2, so that the rotational torque cannot be applied to the rotary shaft portion 4.

The present invention has been made in view of such circumstances, and provides a variable resistor capable of reducing scraping off of a resistance pattern that causes electrical noise and obtaining a sufficient rotational torque. The purpose is to do.

<Means for Solving the Problems> In order to achieve the above object, the present invention has a variable resistor configured as follows. That is, a case having upper and lower openings, an insulating substrate mounted in the case and provided with a resistance pattern on the inner surface of the case, a lower end thereof faces the inside of the case, and an outer peripheral surface of the lower end is an inner peripheral surface of the case. A resin-made rotating shaft part rotatably attached to the upper opening of the case and a slider that is provided integrally with the lower end of the rotating shaft part in a state of facing each other and slides on the resistance pattern. The outer peripheral surface of the rotating shaft portion is provided with a resin elastic body that extends in the radial direction and the extended end of which is in pressure contact with the inner peripheral surface of the case, and the inner peripheral surface of the case is , A recess that is elastically engaged with the extended end of the elastic body is provided, and the recess is provided at a position in the rotation range of the rotary shaft portion where the slider does not slide on the resistance pattern during normal use. And variable from the above You configure the anti-vessel.

<Operation> According to the above configuration, the rotating shaft portion is rotatably attached to the case by elastically contacting the elastic body with the inner peripheral surface of the case, and the rotating torque of the rotating shaft portion is the elastic contact force of the elastic body. Will also be obtained. Therefore, the slider does not need to serve to impart the rotational torque by itself, and it is not necessary to press it against the resistance pattern excessively.

In addition, during the manufacturing of this variable resistor, the rotary shaft is rotated to a position in the rotational arrangement of the rotary shaft where the slider does not slide during normal use on the resistance pattern to extend the elastic body. If you put the end into the recess, the elastic body will not be elastically deformed. If the heating required for curing the adhesive or the thermosetting resin layer is applied in this state, the elastic body will not be thermally deformed.

Since the slider is provided at a position on the resistance pattern where the slider does not slide during normal use in the rotational arrangement of the rotary shaft, the extension end of the elastic body is not recessed during normal use. It doesn't get in.

<Example> Hereinafter, the present invention will be described in detail based on an example shown in the drawings. FIG. 1 is a 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 high-voltage variable resistor 1 is basically the same as that of the conventional high-voltage variable resistors 20 and 30, 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 rotating shaft portion 4 has a spring member 12
That is, the (elastic body) is provided and the recess 13 is formed in the peripheral wall 7a of the storage recess 7.

The rotary shaft portion 4 is formed of an integrally molded product of resin such as modified PPO (polyphenylene oxide) or PBT (polybutylene terephthalate), and the spring member 12 is also attached to the rotary shaft portion 4 by integral molding. That is, the spring member 12 has the flange peripheral surface 1 at a predetermined position on the flange peripheral surface 10a.
It is formed so as to extend outwardly and forms an elastic force in the radial direction of the flange 10 (the radial direction of the rotary shaft portion 4).

The storage recess 7 of the case 2 is formed in a cylindrical shape larger than the flange 10 to be stored. On the other hand, since the spring member 12 forms an elastic force in the radial direction of the rotary shaft portion 4, when the spring member 12 is not housed in the housing recessed portion 7, its extension end is extended.
The turning radius of 12a is set to be larger than the radius of the storage recess 7.

Further, at a predetermined location (lower side in the figure) of the storage recess peripheral wall 7a,
A recess 13 into which the extended end 12 of the spring member 12 is inserted is formed. The recess 13 has a size and a depth such that when the spring member 12 enters, the recess 13 returns to the original shape before the deformation. In addition, the region where the recess 13 is formed is set outside the rotational sliding range of the slider 5 in a normal use state.

When the rotary shaft portion 4 is rotatably attached to the case 2, the flange peripheral surface 10a faces the storage recess peripheral wall 7a, and the spring member 12 elastically deforms to elastically contact the storage recess peripheral wall 7a. This elastic contact force becomes the rotation torque of the rotary shaft portion 4. Then, when the rotary shaft portion 4 is rotated to the position of the recess 13, the spring member 12 enters the recess 13 and its elastic force is released.

Also in this variable resistor 1, when the insulating substrate 3 is mounted in the case 2, the resistance pattern 8 on the insulating substrate 3 is formed.
Will come into contact with the slider 5. However, the rotating torque of the rotating shaft portion 4 is also obtained by the spring member 12. Therefore, the slider 5 does not have to be pressed against the resistance pattern 8 with an elastic force more than necessary, and the spring pressure of the slider 5 is set in consideration of this point.

Next, a manufacturing process of the high voltage variable resistor 1 will be described.

First, the rotating shaft portion 4 is attached to the case 2. Then, the insulating substrate 3 is placed on the case 2 via the adhesive A, and is cured by heating and attached. Then, a thermosetting resin such as an epoxy resin is injected into the case 2 from the outside of the lower end opening 2b of the case and cured by heating to form the thermosetting resin layer S on the entire surface of the lower end opening 2b. The thermosetting resin may also partly penetrate the case inner surface of the insulating substrate 3. Adhesive A above
And the extension end 12a of the spring member 12 when the thermosetting resin is cured.
Let's get into the dent 13. (See FIG. 3) By doing so, the spring member 12 is not thermally deformed.

After the thermosetting resin layer S is hardened, the rotary shaft portion 4 is rotated to cause the extended end 12a of the spring member 12 to escape from the recess 13, and the spring member 12 elastically abuts the storage recess peripheral wall 7a, A predetermined rotation torque is applied to the rotary shaft portion 4.

The high-voltage variable resistor 1 has protrusions 14, 14 for limiting the rotation range formed on the flange 10 and step portions 15, 15 formed in the storage recess 7. Therefore, the rotation range of the rotary shaft portion 4 is restricted. Therefore,
In the present embodiment, the formation position of the recess 13 is set so that the extending end 12a of the spring member 12 enters the recess 13 when the rotary shaft portion 4 reaches the one end of rotation. Therefore, the work of moving the extended end 12a of the spring member 12 to the position of the recess 13 can be performed easily and reliably.

In the above embodiment, the spring member 12 is cantilevered by the flange 10, but as shown in FIG. 4, both ends 12b, 12c of the spring member 12 are supported by the flange 10. It is also possible that

Further, in the above embodiment, the spring member 12 is formed integrally with the rotary shaft portion 4, but it may be separately formed as a separate member and then attached integrally. Also, the mounting of the insulating substrate 3 in the case 2 is
The means is not limited to the adhesive A as in the above embodiment, and other means may be used. Further, the insulating substrate 3 may be attached to the case 2 with the adhesive A and the thermosetting resin S may not be formed.

<Effects of the Invention> As described above, according to the present invention, the rotation torque can be obtained by the elastic member provided on the rotation shaft portion. Therefore, it is no longer necessary for the slider to be pressed against the resistance pattern with an elastic contact force that is larger than necessary. Therefore, the resistance pattern is less likely to be scraped off due to the sliding of the slider, and it becomes possible to apply an appropriate rotational torque to the rotary shaft portion without causing the inconvenience of electrical noise.

Further, during the manufacturing of this variable resistor, it has become possible to apply the heating required for resin curing of the adhesive and the thermosetting resin layer in a state where the elastic body is not elastically deformed. Therefore, the elastic body is thermally deformed by heat to weaken its elastic repulsion force, and the disadvantage that a sufficient rotation torque cannot be applied to the rotation shaft portion does not occur.

Further, during normal use, the extended end of the elastic body does not enter the recess, and the engagement between the extended end and the recess does not hinder the rotation of the rotating shaft portion.

[Brief description of drawings]

1 to 3 relate to an embodiment of the present invention. FIG. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. FIG. 3 is a sectional view similar to FIG. 2.
FIG. 4 is a sectional view similar to FIG. 2 according to another embodiment. FIG. 5 is a vertical sectional view of a conventional example. 6 to 7 relate to a variable resistor for explaining the basic structure of the present invention, FIG. 6 is a vertical sectional view, and FIG. 7 is a sectional view taken along line VII-VII of FIG. 1 …… Variable resistor 2 …… Case 2a, 2b …… Case opening 3 …… Insulating substrate 3a …… Insulating substrate inner surface 3b …… Insulating substrate side 3c …… Insulating substrate outer surface 4 …… Rotating shaft 5 …… Slider 7a …… Storing recess peripheral surface (case inner peripheral surface) 8 …… Resistance pattern 10 …… Flange (rotating shaft lower end) 10a …… Flange peripheral surface (rotating shaft outer peripheral surface) 12: Spring member (elastic body) 12a: Extended end of spring member 13: Recess A: Adhesive S: Thermosetting resin layer

Claims (1)

[Claims] 1. A case (2) having upper and lower openings; an insulating substrate (3) mounted in the case (2) and provided with a resistance pattern (8) on an inner surface (3a) of the case. With the lower end (10) facing the inside of the case (3) and the lower end outer peripheral surface (10a) facing the inner peripheral surface (7a) of the case,
A rotation shaft portion (4) made of resin rotatably attached to the upper opening (2a) of the case (2) and a lower end (10) of the rotation shaft portion (4) are rotatably provided integrally with each other. Slider (5) sliding on the resistance pattern (8)
The rotating shaft portion (4) has an outer peripheral surface (10a) extending in the radial direction, and the extending end (12a) of the rotating shaft portion (4) has an inner peripheral surface (7a) of the case.
An elastic body (12) made of resin that is pressed against the elastic body (1) is provided on the inner peripheral surface (7a) of the case (2).
A recess (13) that elastically engages with the extended end (12a) of 2) is provided. A variable resistor, which is provided at a position on the resistance pattern (8) that does not slide during normal use.