JPH05129112A - Variable resistor for high tension and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a variable resistor for high voltage which has no dielectric breakdown under the normal environmental conditions and requires the reduced number of manufacturing processes and is to be used in one body with a flyback transformer. CONSTITUTION:There are provided a first insulating substrate 1 which has a film resistor formed on one surface; a second insulating substrate 5 which has a film resistor formed on one surface; a first insulating case 16 with an opening, which houses the first insulating substrate 1 coated with resin (26); and a second insulating case 23 with an operating, which houses the first insulating case 16 so that its opening face in the same direction with that of the second insulating case 23 and houses the second insulating substrate 5 so that the film resistor faces the bottom of the case 23. Then, a surface of the second insulating substrate 5 opposite to the film resistor is filled with insulating resin 24, which is then hardened. Each space formed between sections is filled with resin 25 which is the same as the filling resin of a flyback transformer to be incorporated in one body with the device.

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 and a display monitor, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, variable resistors for high voltage have been often used integrally with a flyback transformer that provides a predetermined voltage to the anode of a cathode ray tube of a television receiver or a display monitor. As shown in FIG. 6, this type of high-voltage variable resistor includes insulating substrates 1 and 5 provided with film resistors forming a fixed resistance portion and a variable resistance portion, and sliders 21 and 22. The rotating shafts 19 and 20 are housed in an insulating case 30 having a one-sided opening supported by bearings 17 and 18, and are insulated except for a film resistor portion forming a variable resistance portion of the insulating substrate 5. The resin 24 and 25 are filled and cured.

[0003]

However, the high-voltage variable resistor having the above-mentioned conventional structure has a good adhesion to the substrate, a small coefficient of thermal expansion, a relaxation of stress, a high insulation resistance, etc. It is necessary to have a good quality casting resin that satisfies the above conditions. Also, since the high voltage part of about 30 kV to 40 kV is resin-molded, it is necessary to perform resin molding in a vacuum state so that air bubbles and the like do not remain in the insulating resin. It costs. Therefore, a considerable economic burden and man-hours are required in the manufacturing process of the variable resistor. In addition, since it is often used integrally with the flyback transformer, internal heat generation is large and thermal stress is easily applied, so that peeling occurs between the insulating resin of the flyback transformer and the insulating resin of the high-voltage variable resistor, Also, since it is a high voltage generating part, dust and oil components in the atmosphere are likely to adhere, cracks occur in the insulating case, moisture in the atmosphere gradually penetrates into the insulating resin, and the insulation resistance of the insulating resin itself gradually deteriorates. , It adversely affects the film resistor forming the fixed resistor. In addition, the insulating case is modified PPO (polyphenylene oxide) or PBT.
It is obtained by molding using a molding resin such as (polybutylene terephthalate). The insulating resin is a thermosetting resin such as an epoxy resin, and the insulating substrate is a ceramic such as alumina. In this case, the adhesiveness between the respective materials is weak, and peeling between different materials easily occurs due to thermal stress due to internal heat generation, mechanical shock from the outside, and thermal shock.
There are problems that expansion and contraction occur due to repeated driving and stopping of the flyback transformer, and peeling grows. Due to these problems, corona discharge occurs, which in turn causes insulation breakdown, resulting in a great deal of damage to television receivers, display monitors and the like.

The present invention solves the above-mentioned problems of the prior art, and does not cause dielectric breakdown under generally used environments and conditions, and a high voltage used in combination with a flyback transformer in which the number of manufacturing steps is reduced. It aims at providing the variable resistor for.

[0005]

In order to achieve the above object, a high voltage variable resistor according to the present invention comprises a first insulating substrate on which a film resistor forming a fixed resistance portion is formed on one surface. A second insulating substrate having a film resistor forming a variable resistance portion formed on one surface thereof; a first insulating case having a one-sided opening shape accommodating a resin-coated first insulating substrate; A second insulating case having a one-sided opening shape in which the insulating case is housed so that the opening surfaces thereof face in the same direction, and the second insulating substrate is housed so that the surface of the film resistor faces the bottom surface of the case; A rotary shaft pivotally supported on the bottom surface of the case; a slider that slides on the film resistor of the second insulating substrate in conjunction with the rotary shaft; and a film resistor of the second insulating substrate. An insulating resin which is filled and hardened on the opposite surface to the first insulating case. A configuration in which the inner gap, the gap between the first insulating case and the second insulating case, and the opening of the second insulating case are filled with the same resin as the filling resin of the flyback transformer integrally mounted. I have to.

[0006]

In the above structure, the second insulating case is connected to the PBT.
By using a material such as the above, the case will not be cracked due to the adhesion of chemicals or oil from the outside. However, since there is a problem in terms of physical properties that water easily permeates, the insulating resin with which the flyback transformer is filled is resistant to moisture, and the first insulating case is formed of a material such as modified PPO. A high voltage variable resistor that protects the insulating substrate from moisture and has excellent chemical resistance, oil resistance and water resistance.

Even if a crack is generated in the second insulating case due to some reason, the fixed resistance portion, which is a high voltage portion, is surrounded by the double structure of the insulating case, and therefore protected by the first insulating case. However, there is no risk of dielectric breakdown of the film resistor of the insulating substrate. In addition, the fixed resistor parts of the flyback transformer and high voltage variable resistor are filled with the same insulating resin, so the insulating resin of the flyback transformer is affected by thermal stress due to internal heat generation and mechanical shock from the outside. There is no need to worry about the insulating resin of the high voltage variable resistor peeling off. Furthermore, in the resin casting work, the one that has a shorter curing time than the currently used casting resin is used, and because the casting point is a low voltage part of about 10 kV, the resin casting is performed in a vacuum state. You don't have to do it. Therefore, the manufacturing time is shortened as a whole.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a sectional view of a high voltage variable resistor according to the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a rear view thereof. In FIG. 1, reference numerals 1 and 5 denote first and second insulating substrates made of a ceramic material such as alumina porcelain, and a fixed resistance portion is formed on one surface of the first insulating substrate 1 shown in FIG. A meandering film resistor 2 and terminal electrodes 3 and 4 are provided, and a variable resistance portion is formed on one surface of a second insulating substrate 5. The horseshoe-shaped film resistors 6 and 7 and the center electrode shown in FIG. 8, 9
, The terminal electrodes 12, 13, 14, 15 and the film electrodes 10, which sandwich the center electrodes 8, 9 and the terminal electrodes 13, 14.
11 is provided.

Reference numeral 23 in FIG. 1 is a second insulating case having a one-sided opening shape, which has bearing portions 17, 18 on the bottom surface thereof, and the second insulating substrate 5 is provided on the opening side thereof with the film resistors 6, 7 and. The surface on which the terminal electrodes 12 to 15 are provided is the second insulating case 2
It is fixed to the bottom surface of 3 by an adhesive or the like.
Reference numeral 16 denotes a first insulating case having a one-sided opening shape. In this embodiment, the first insulating substrate 1 coated with resin 26 on the opening side is provided with the film resistor 2 and the terminal electrodes 3 and 4. Although it is fixed to the bottom surface of the first insulating case 16 with an adhesive or the like, it does not matter if the film resistor 2 of the first insulating substrate 1 faces the opening surface side. Then, the first insulating case 16 accommodating the first insulating substrate 1
Is stored in the second insulating case 23, and the back side surface of the second insulating substrate 5 is filled with an insulating resin 24 such as epoxy resin. After that, an insulating resin 25 such as an epoxy resin is filled integrally with the flyback transformer. At this time, the first
The gap between the insulating case 16 and the second insulating case 23, the gap in the first insulating case 16 housing the first insulating substrate 1, and the like are filled with the insulating resin 25. Reference numerals 19 and 20 denote bearing portions 17 of the second insulating case 23,
Sliders 21 and 22 that slide on the horseshoe-shaped film resistors 6 and 7 of the variable resistance portion of the second insulating substrate 5 centering on the center electrodes 8 and 9 are respectively supported by the rotary shafts 18 supported by the rotary shafts 18. I have each. Although not shown, the rotary shaft has a structure that does not rotate more than a predetermined angle.

In the above structure, the second insulating case 23
By forming PBT from a material such as PBT, the case is not cracked due to the adhesion of chemicals or oil from the outside. However, since there is a problem in physical properties that water easily permeates, the same insulating resin 25 as the filling resin with which the flyback transformer is filled is resistant to moisture, and the first insulating case 16 is made of modified PPO or the like. By forming the material,
The fixed resistance portion of the first insulating substrate 1 can be protected from moisture. From these, the variable resistor for high voltage has excellent chemical resistance, oil resistance and water resistance.

If, for some reason, the second insulating case 2
Even if cracks occur in 3
Since the fixed resistance part of the insulating substrate 1 is surrounded by the double structure of the insulating case, it is protected by the first insulating case 16.
The film resistor of the first insulating substrate 1 is not adversely affected, and there is no risk of dielectric breakdown. It should be noted that the thermal expansion coefficients of the materials used are in descending order of (coating resin 26 and insulating resin 24) ≧ first insulating case 16 ≧ insulating resin 25 same as the filling resin of the flyback transformer ≧ second insulating case 23 ≧ If the first and second insulating substrates 1 and 5 are used,
Adhesion between the materials with respect to thermal cycles is good.

The high voltage variable resistor of the present invention is constructed as described above, but is not necessarily limited to the structure of the above embodiment. For example, the resin 26 coating the fixed resistance portion of the first insulating substrate 1 or the first
The method of connecting the second insulating substrates 1 and 5 and the shape and number of the insulating substrates are completely arbitrary. The point is that the fixed resistance part, which is the high voltage part, is doubly covered with two insulating cases and the periphery of the fixed resistance part is filled with the resin of the flyback transformer. It is possible.

[0013]

As is apparent from the above description, the high-voltage variable resistor of the present invention comprises the first insulating case made of a material such as modified PPO and the first insulating case made of a material such as PBT. By making the fixed resistance part of the high voltage part doubly covered with the insulation case of 2, and by filling the flyback transformer and the periphery of the fixed resistance part with the same insulating resin,
It has excellent chemical resistance, oil resistance and water resistance. Even if a crack occurs in the second insulating case due to some reason, it can be protected by the first insulating case. And, there is no fear that the insulating resin of the flyback transformer and the insulating resin of the high-voltage variable resistor will be peeled off due to stress, etc., and the insulation breakdown of the fixed resistance part is unlikely to occur.
Excellent performance in reliability life tests.

The expansion coefficient of the first insulating case is 60.
By using a material having a certain degree, stress is applied to the first insulating case and the insulating resin in the operating state of the high voltage variable resistor, and the insulating resin is prevented from cracking starting from the first insulating case. In addition, the internal structure is slightly more complicated than the current high-voltage variable resistor, but since the resin casting part is a low-voltage part of about 10 kV, it does not need to be cast in a vacuum state. Since a resin having a shorter curing time than that of the casting resin used for the resistor is used, there is an advantage that the manufacturing time can be shortened as a whole.

[Brief description of drawings]

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

FIG. 2 is a front view of a high-voltage variable resistor according to the present invention.

FIG. 3 is a rear view of the high-voltage variable resistor according to the present invention.

FIG. 4 is a front view of a fixed resistance portion of an insulating substrate used in the high-voltage variable resistor of the present invention.

FIG. 5 is a front view of a variable resistance portion of an insulating substrate used for the high voltage variable resistor of the present invention.

FIG. 6 is a sectional view of a conventional high-voltage variable resistor.

[Explanation of symbols]

1 First Insulating Substrate 5 Second Insulating Substrate 16 First Insulating Case 19, 20 Rotating Shaft 21, 22 Slider 23 Second Insulating Case 24 Insulating Resin 25 Insulating Resin Same as Filling Resin for Flyback Transformer 26 Coating resin

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01F 19/04 P 7129-5E

Claims (4)

[Claims] 1. A first insulating substrate on which a film resistor forming a fixed resistance portion is formed on one surface, and a second insulating substrate on which a film resistor forming a variable resistance portion is formed on one surface. , A first insulating case having a one-sided opening shape accommodating a resin-coated first insulating board, a second insulating board so that the opening surfaces of the first insulating case face the same direction, and a film resistor. A second insulating case having a one-sided opening shape that is accommodated such that the surface of the second insulating case faces the bottom surface of the case, a rotary shaft pivotally supported by the bottom surface of the second insulating case, and the second shaft in conjunction with the rotary shaft. A slider sliding on the film resistor of the insulating substrate, and an insulating resin that is filled and cured on the surface of the second insulating substrate opposite to the surface of the film resistor, Gap and the gap between the first insulating case and the second insulating case and the second Variable resistor for high voltage opening edge casing is filled with the same insulating resin filling the resin of the flyback transformer mounted together. 2. The coefficient of thermal expansion of the material used is (resin coated on the first insulating substrate and insulating resin filled and cured on the surface opposite to the surface of the film resistor of the second insulating substrate) ≧ first
2. The high-voltage variable resistor according to claim 1, wherein the insulating case is equal to or more than the insulating resin which is the same as the filling resin of the flyback transformer, the second insulating case is the first insulating substrate, and the second insulating substrate is the second insulating substrate. 3. The high voltage variable resistor according to claim 1, wherein the material of the first insulating case is modified PPO (polyphenylene oxide) and the material of the second insulating case is PBT (polybutylene terephthalate). .. 4. A filling of a flyback transformer that is integrally mounted in a gap in the first insulating case, a gap between the first insulating case and the second insulating case, and an opening of the second insulating case. The method of manufacturing a high voltage variable resistor according to claim 1, wherein the same insulating resin as the resin is simultaneously filled.