JPH08273909A - Variable resistor for high tension - Google Patents

Abstract

PURPOSE: To provide a variable resistor for high tension in which a stress applied to a board due to the expansion and the contraction of a resin is relaxed and in which the separation and the degradation of a resistor element formed on the board are suppressed. CONSTITUTION: A variable resistor for high tension is constituted in such a way that a board 20 on which a resistor for a variable resistor part and a resistor for a fixed resistor part are formed so as to be continued on one face is housed inside a case 1 in which the variable resistor part 2 and the fixed resistor part 3 are installed so as to be partitioned by a partition wall 1a and one face of which is opened, that a resin 6 is molded and formed on the whole opening part of the case 1 and inside the fixed resistor part 3 and that a bottom wall surface 1c is formed in an inclined shape so as to make the distance between the bottom wall surface 1c of the fixed resistor part 3 and the board 20 shorter on the side of the partition wall 1a than the side-face side of the case 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage variable resistor used in a television receiver or the like.

[0002]

2. Description of the Related Art Conventionally, this type of high-voltage variable resistor is constructed as shown in FIGS. 3 and 4, for example. FIG.
Is a rear view of the high-voltage variable resistor, and FIG.
It is sectional drawing of an X-ray.

As shown in FIGS. 3 and 4, this high-voltage variable resistor is a synthetic resin having a one-sided opening in which a variable resistor section 2 and a fixed resistor section 3 are separated by a partition wall 1a. In the case 1 made of metal, the surface facing the bottom surface of the case 1 (see FIG.
On the inner wall surface of the variable resistor section 2, a substrate 20 made of ceramics such as alumina, which is formed by continuously connecting a variable resistor section resistor 22 and a fixed resistor section resistor 23 on the The support step portion and the partition wall 1a are bonded and fixed with an adhesive, and the rotating shafts 5 having a slider 5a are borne on the bottom portion of the variable resistor portion 2 to support the opening surface side of the case 1 and the fixed resistor. An epoxy resin 6 (not shown in FIG. 3) is filled inside the portion 3. An epoxy adhesive, a silicone adhesive, or the like is used as the adhesive.

The variable resistor portion resistor 22 is formed so that a space is formed between the fixed resistor portion resistor 23 of the substrate 20 and the side wall surface of the fixed resistor portion 3 of the case 1. The partition wall 1a of the case 1 is formed to be smaller than the formed region, and is located at the boundary between the region of the substrate 20 where the variable resistor portion resistor 22 is formed and the region where the fixed resistor portion resistor 23 is formed. Is formed. That is, the resin 6 is filled so as to cover only the back surface of the substrate 20 in the area where the variable resistor portion resistor 22 is formed and cover both surfaces in the area where the fixed resistor portion resistor 23 is formed.

As described above, the resin 6 is also filled inside the fixed resistor portion 3 so as to cover both surfaces of the area where the fixed resistor portion resistor 23 is formed. This is to improve the insulation on the side of the vessel.

It should be noted that required electrodes are formed on the surface of the substrate 20, and the earth terminal 24, the input terminal 25, and the output terminals 26, 26 connected to these electrodes are attached to the substrate 20.
It is pulled out from the back side. The input terminal 25 is electrically connected to one end of the fixed resistor section resistor 23, and a high voltage from a high voltage generator such as a flyback transformer is input to the input terminal 25. Each output terminal 26 is electrically connected to one end of the slider 5a via an electrode, and a focus voltage and a screen voltage are output from each output terminal 26.

[0007]

However, in the above-mentioned conventional high-voltage variable resistor, when a rapid temperature change such as heat shock is repeatedly applied, a part of the fixed resistor part resistor 23 near the partition wall 1a is formed. There is a problem that (the portion shown by the circle in FIG. 4) peels off. This means that only one surface of the substrate 20 is covered with the resin 6 in the region where the variable resistor portion resistor 22 is formed, and both surfaces are covered with the resin 6 in the region where the fixed resistor portion resistor 23 is formed. Resistor 2
Since the amount of resin in the region where 3 is formed is large, the stress of expansion and contraction of the resin 6 due to temperature change is fixed to the region where the variable resistor portion resistor 22 of the substrate 20 is formed with the partition wall 1a as a barrier. It is considered that this is because the strength is different from that of the region in which the chamber resistor 23 is formed, and moreover, it is added to the substrate 20 with a large difference. That is, it is considered that the stress applied to the substrate 20 due to the expansion and contraction of the resin 6 is concentrated in the vicinity of the partition wall 1a and the substrate 20 is largely deformed in the vicinity of the partition wall.

Further, the peeling of the resistor has a significant difference depending on the kind of the adhesive between the substrate and the case, and the case where the silicone adhesive is used as the adhesive is more than the case where the epoxy adhesive is used. , Peeling easily occurs. It is considered that this is due to the difference in the adhesive force and the coefficient of thermal expansion of the adhesive.

In order to suppress the peeling phenomenon of the resistor,
Conventionally, the area where the resistor is peeled off has been dealt with by printing coating with a silicone resin, but in this case, there is a problem that the number of printing steps of the silicone resin increases and the manufacturing cost increases.

Therefore, an object of the present invention is to solve the problems of the conventional high-voltage variable resistor as described above, and to alleviate the stress applied to the substrate due to the expansion and contraction of the resin without lowering the insulating property. Therefore, it is an object of the present invention to provide a highly reliable high-voltage variable resistor in which peeling and deterioration of the resistor are suppressed and characteristic deterioration is small.

[0011]

In order to achieve the above object, the present invention provides a case in which a variable resistor section and a fixed resistor section are internally divided by a partition wall to form a one-sided opening, A substrate formed by connecting the variable resistor part resistor and the fixed resistor part resistor in series to each other, and the fixed resistance of the substrate and the back surface of the region of the substrate where the variable resistor part resistor is formed. A variable resistor for high voltage, which is obtained by molding a resin in the entire opening of the case and in the fixed resistor portion so as to cover the front surface and the back surface of the region where the resistor portion is formed, in the bottom wall surface of the fixed resistor portion. The bottom wall surface of the fixed resistor portion is formed in an inclined shape or a step shape so that the distance between the substrate and the substrate is shorter on the partition wall side than on the case side surface side.

[0012]

According to the above construction, the distance between the bottom wall surface of the fixed resistor portion of the case and the substrate is formed such that the partition wall side is shorter than the case side surface side, and the distance in the vicinity of the partition wall in the fixed resistor portion is increased. Since the resin thickness is reduced and the amount of resin filled in the fixed resistor portion is reduced, it is possible to reduce the difference in stress applied to the substrate on both sides of the partition wall due to the expansion and contraction of the resin. Therefore, stress in the vicinity of the partition wall of the substrate can be reduced, and peeling and deterioration of the resistor can be suppressed.

Further, since the resin on the side to which the high voltage is applied in the region where the fixed resistor portion resistor is formed is formed thick, the insulating property does not deteriorate.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing the embodiments thereof. In the figure, the same or corresponding parts and those having the same functions as those in the conventional example are designated by the same reference numerals.

FIG. 1 shows the structure of a high voltage variable resistor according to the first embodiment of the present invention. FIG. 1 is a cross-sectional view of a high voltage variable resistor and is a view corresponding to FIG. 4 of a conventional example.

As shown in FIG. 1, in the high voltage variable resistor of this embodiment, the bottom wall surface 1 inside the fixed resistor portion 3 of the case 1 is used.
c is formed so as to be inclined so that the distance from the substrate 20 on the side of the partition wall 1a is shorter than the distance from the substrate 20 on the side of the case, and the resin 6 filled in the fixed resistor unit 3 is It is filled so that it gradually becomes thinner as it approaches the partition wall 1a from the side surface side. The configuration other than the above is the same as that shown in FIGS. 3 and 4 of the conventional example,
The description is omitted.

The structure of the high voltage variable resistor according to the second embodiment of the present invention is shown in FIG. As shown in FIG. 2, in the high-voltage variable resistor of the present embodiment, the bottom wall surface 1c inside the fixed resistor portion 3 of the case 1 is separated from the board 20 on the partition wall 1a side by the board 20 on the side surface side of the case. The resin 6 which is formed in a step shape and is filled in the fixed resistor portion 3 so as to be shorter than the distance from
Is filled so that the thickness of the partition wall 1a side is thinner than that of the case side surface side. The configuration other than the above is the same as that shown in FIGS. 3 and 4 of the conventional example,
The description is omitted.

In the configurations of the first and second embodiments, the thickness of the resin 6 near the partition wall 1a in the fixed resistor portion 3 is reduced and the amount of resin 6 filled in the fixed resistor portion 3 is reduced. Therefore, the stress difference between the expansion and contraction of the resin 6 on both sides of the partition wall 1a of the substrate 20 of the resin 6 can be reduced without reducing the insulating property.

As a result of a heat shock test performed on the high-voltage variable resistors having the configurations of the first and second embodiments, a fixed resistor portion in the vicinity of the partition wall is printed without printing a silicone resin to reinforce the resistor. It was possible to significantly reduce the peeling phenomenon of the resistor.

Incidentally, the bottom wall surface 1c in the first embodiment.
The inclination degree and the step shape and size in the second embodiment are appropriately set according to the required dielectric strength, the type of adhesive between the substrate 20 and the case 1, the type of resin, and the like.

In addition, in the first embodiment, the bottom wall surface 1c of the fixed resistor portion 3 is formed by an inclined flat surface, but it is not limited to this, and it may be formed by an inclined curved surface. Although it is formed to have one step in the embodiment, it may be formed to have a plurality of steps. Further, the inclined surface and the step surface may be combined.

[0022]

As described above, according to the high voltage variable resistor of the present invention, the distance between the bottom wall surface of the fixed resistor portion of the case and the substrate is shorter on the partition wall side than on the case side surface side. To reduce the resin thickness in the vicinity of the partition wall in the fixed resistor portion, the amount of resin filled in the fixed resistor portion can be reduced, without lowering the insulation,
It is possible to reduce the stress difference on both sides of the partition wall that is applied to the substrate due to the expansion and contraction of the resin due to temperature change, and thus reduce the stress in the vicinity of the partition wall of the substrate, and prevent peeling and deterioration of the resistor formed on the substrate. can do.

Furthermore, since it is possible to eliminate the printing of the silicone resin for reinforcing the resistor, which is conventionally required, it is possible to reduce the cost.

[Brief description of drawings]

FIG. 1 is a sectional view of a high voltage variable resistor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a high voltage variable resistor according to a second embodiment of the present invention.

FIG. 3 is a rear view of the present invention and the conventional high voltage variable resistor.

FIG. 4 is a cross-sectional view of a conventional high voltage variable resistor.

[Explanation of symbols]

 1 Case 1a Partition wall 1c Bottom wall surface 2 Variable resistor part 3 Fixed resistor part 5 Rotating shaft 5a Slider 6 Resin 20 Board 22 Variable resistor part resistor 23 Fixed resistor part resistor

Claims (1)

[Claims] 1. A variable resistor section resistor and a fixed resistor section resistor are provided on the surface in a case of a one-sided opening in which a variable resistor section and a fixed resistor section are separated by a partition wall. A substrate formed by connecting them is housed so as to cover the back surface of the region of the substrate where the variable resistor portion resistor is formed and the front surface and the back surface of the region of the substrate where the fixed resistor portion resistor is formed. In a high-voltage variable resistor formed by molding resin in the entire opening of the case and in the fixed resistor section, the distance between the bottom wall surface of the fixed resistor section and the substrate is shorter on the partition wall side than on the case side surface side. As described above, the variable resistor for high voltage is characterized in that the bottom wall surface of the fixed resistor portion is formed in an inclined shape or a step shape.