JP2580276Y2 - High-voltage variable resistor - Google Patents

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 fixed to a flyback transformer via a molding resin.

[0002]

2. Description of the Related Art In a high-voltage variable resistor fixed to a flyback transformer, a conductive rubber terminal is used to connect an output terminal of the flyback transformer and an input terminal of the high-voltage variable resistor. Often done. For example, JP-A-60-18904 discloses that a conductive rubber terminal is fixed to a transformer case of a flyback transformer,
Insert the output terminal of the flyback transformer into one end of the conductive rubber terminal located inside the transformer case,
Further, a technique has been proposed in which an input terminal of a high-voltage variable resistor is inserted into the other end of the conductive rubber terminal located outside the transformer case to electrically connect both terminals. However, in this technique, in order to use the wall of the transformer case as a rubber terminal holding member of the conductive rubber terminal, a high-voltage variable resistor fixed to the flyback transformer via a molding resin for molding the flyback transformer includes:
This known technique could not be applied.

Therefore, as shown in Japanese Utility Model Application Laid-Open No. 62-192566, a conductive rubber terminal is connected to a high-voltage variable resistor fixed to the flyback transformer via a molding resin for molding the flyback transformer. A technique has been proposed in which the output terminal of the flyback transformer is fixed to the variable resistor and the output terminal of the flyback transformer is pierced into the conductive rubber terminal. Conventionally, a cylindrical conductive rubber storage portion (rubber terminal holding member) for storing a conductive rubber terminal is provided on the back surface of an insulating substrate having a circuit pattern including a variable resistor formed on the surface,
The conductive rubber terminal was fixed by inserting a conductive rubber terminal into the conductive rubber storage portion until the inner end surface thereof came into contact with the back surface of the insulating substrate. The circuit pattern and the conductive rubber terminal on the surface of the insulating substrate are electrically connected at one end to the circuit pattern and at the other end using a connection terminal penetrating the insulating substrate and stabbed into the conductive rubber terminal. . Then, the opening of the insulating case of the high-voltage variable resistor is filled with a soft insulating resin so as to substantially cover the back surface of the insulating substrate and expose the outer end surface of the conductive rubber terminal. Is formed.

[0004]

As described above, in the conventional structure, the inner end surface of the conductive rubber terminal is in contact with the back surface of the insulating substrate. However, in a high-voltage variable resistor,
Due to the difference in the coefficient of thermal expansion of each member (insulating case, insulating substrate, insulating resin layer, etc.), a force is generated to separate the insulating resin layer from the insulating substrate. Is repeated, the insulating resin layer peels off from the contact portion between the inner end surface of the conductive rubber terminal and the back surface of the insulating substrate. When this peeling spreads, creeping discharge occurs along the back surface of the insulating substrate, and a serious accident such as burning may occur.

It is an object of the present invention to provide a high-voltage variable resistor that can solve the above-mentioned problems.

[0006]

According to the present invention, an insulating substrate provided with a circuit pattern including a resistor for a variable resistor on the front surface is disposed in an insulating case having an open end so that the back surface faces the case opening. The conductive rubber terminal electrically connected to the circuit pattern provided on the surface of the insulating substrate is held on the back side of the insulating substrate by a rubber terminal holding member, and the back surface of the insulating substrate is inserted into the case opening of the insulating case. An improvement is directed to a high-voltage variable resistor in which an insulating resin layer is formed so as to be covered so as to cover the insulating resin layer, and a case opening side of the insulating case is fixed to a flyback transformer via a mold resin.

According to the first aspect of the present invention, the rubber terminal holding member holds the conductive rubber terminal such that the conductive rubber terminal is separated from the back surface of the insulating substrate and an insulating resin is interposed between the back surface and the back surface. Moreover, the cross-sectional shape is substantially circular so as not to cause separation between the insulating resin layer and the back surface of the insulating substrate.
The lead wire is bent . Here, in order to prevent separation from occurring between the insulating resin layer and the back surface of the insulating substrate, an interface between the insulating resin layer and the back surface of the insulating substrate where both are not in contact (a non-contact interface). It is not to make as much as possible. Even when a non-contact interface is formed, the amount should be limited to such an extent that separation between the insulating resin layer and the back surface of the insulating substrate is not easily caused. Therefore, in the present invention, a structure is employed in which the conductive rubber terminals are floated from the back surface of the insulating substrate and the rubber terminal holding member itself does not cause peeling between the insulating resin layer and the back surface of the insulating substrate. . Most preferably, the rubber terminal holding member is completely in non-contact with the back surface of the insulating substrate.However, even when the rubber terminal holding member has to be brought into contact with the back surface of the insulating substrate, the cross-sectional shape is substantially circular. Bend the lead wire
When configured, the contact area should be as small as possible
Can be .

According to the second aspect of the present invention, the conductive rubber terminal is held by the rubber terminal holding member such that a part of the conductive rubber terminal is located in the insulating resin layer formed of the insulating resin.

According to the third aspect of the present invention, the conductive rubber terminal is formed by the rubber terminal holding member so as to form a gap filled with the mold resin between the conductive rubber terminal and the insulating resin layer formed of the insulating resin. Hold.

According to the invention of claim 4, the rubber terminal holding member is a disconnection for electrically connecting the circuit pattern and the conductive rubber terminal.
It is constituted by a lead wire having a substantially circular surface shape .

According to the invention of claim 5, the end of the lead wire to which the conductive rubber terminal is attached is fitted with the conductive rubber terminal.
Bend to form a loop to be formed .

[0012] In the invention of claim 6 has an extension for positioning the conductive rubber terminals extend along the lead wire to the back surface of the insulating substrate in a desired position.

[0013]

The sectional shape as specified in the invention of claim 1 is almost the same.
When the conductive rubber terminal is separated from the back surface of the insulating substrate by using a rubber terminal holding member formed by bending a circular lead wire and the conductive rubber terminal is held so that the insulating resin is interposed between the back surface and the conductive rubber terminal. Even if a force is required to separate the insulating resin layer and the back surface of the insulating substrate due to the difference in the coefficient of thermal expansion of each member, the separation between the insulating resin layer and the back surface of the insulating substrate can be easily performed. A large non-contact interface (an interface where the insulating resin layer and the insulating substrate are not in contact with each other) is not formed. Therefore, according to the present invention, separation between the insulating substrate surface and the insulating resin layer can be prevented, and creeping discharge can be prevented along the back surface of the insulating substrate. Also, as in the present invention, the lead wire is
The cross-sectional shape in the orthogonal direction is almost circular with no corners.
Use of lead wires embedded in insulating resin
This prevents cracks in the insulating resin layer
You.

In the case where the thickness of the insulating resin layer is large, the conductive rubber terminal may be arranged such that a part of the conductive rubber terminal is located in the insulating resin layer formed by the insulating resin. , The thickness of the entire high-voltage variable resistor can be reduced.

In the case where the thickness of the insulating resin layer is small, or when there is a lead wire such as a capacitor on the back side of the insulating substrate, the conductive rubber terminal is separated from the insulating resin layer. With such arrangement, the dielectric strength of the insulating resin layer is not reduced. Then, when the conductive rubber terminal is held so as to form a gap filled with the mold resin of the flyback transformer between the two, if the thickness of the insulating resin layer is thin, the mold resin filled in the gap becomes the conductive rubber terminal. To form an insulating reinforcing layer. Even when a thick thickness of the insulating resin layer, since the gap is completely filled with molding de resin, when attached via the flyback transformer to molded resin high-voltage variable resistor, insulating the mold resin layer It is possible to prevent air bubbles that lower the proof stress from remaining.

According to a fourth aspect of the present invention, when the rubber terminal holding member is formed by a lead wire for electrically connecting the circuit pattern and the conductive rubber terminal, another component for fixing the conductive rubber terminal is required. The number of parts can be reduced because it is eliminated. In this case, in particular, when a lead wire having a cross-sectional shape that comes into contact with a flat surface with only a small contact area, such as a circular cross-sectional shape, is used, even when the lead wire is arranged along the back surface of the insulating substrate, The non-contact interface formed between the substrate and the back surface of the insulating substrate can be minimized.

According to the fifth aspect of the present invention, even when the rubber terminal holding member is formed by using the lead wire, the conductive rubber terminal is not displaced in a direction orthogonal to the plate surface of the insulating substrate.
The operation for filling the insulating resin with the conductive rubber terminals separated from the back surface of the insulating substrate is facilitated.

According to the invention of claim 6, the extension of the lead wire.
By appropriately changing the length and the bending direction of the portion, the position of the conductive rubber terminal can be appropriately determined.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

FIGS. 1A and 1B are partial sectional views showing an embodiment in which the present invention is applied to a high-voltage variable resistor used for adjusting a focus voltage of a cathode ray tube, and before filling with an insulating resin. The bottom views are shown respectively. FIG. 1
In (A), the structure of the slider part is omitted, and the insulating resin is drawn as transparent for easy understanding. In these figures, reference numeral 1 denotes an insulating case having an open end at one end made of an insulating resin material such as PBT (polybutylene terephthalate). On the inner wall of the insulating case 1, there are formed a peripheral rib 1a on which an insulating substrate 2 made of alumina ceramic is placed and a rib (not shown) surrounding the periphery of the terminal electrode. On the surface 2a of the insulating substrate 2,
Although not shown, a circuit pattern including a variable resistor is formed. At one end of the insulating case 1 in the longitudinal direction, a flange portion 1b extending in the longitudinal direction is integrally provided, and two earth terminals 3 and 4 are supported on the flange portion 1b. One end of each of the ground terminals 3 and 4 is fixed to the back surface 2b of the insulating substrate 2 using an adhesive. A pair of through holes are formed in the insulating substrate 2 corresponding to the ground terminals 3 and 4, and the protrusions formed at the ends of the ground terminals 3 and 4 are fitted into the pair of through holes, respectively. The protruding portion of the ground terminal 4 is electrically connected to a circuit pattern formed on the surface 2a of the insulating substrate 2. One lead wire 5a of the capacitor 5 is connected to the ground terminal 3 by soldering. The capacitor 5 is
It is placed between the focus output and ground,
The capacitor 5 does not always have to be provided together with the high-voltage variable resistor, and some high-voltage variable resistors are not provided with this capacitor.

A cylindrical terminal guide tube 1c is formed integrally with the other end of the insulating case 1, and the output terminal 6 is inserted and supported in the terminal guide tube 1c. An inner end 6a of the output terminal 6 is connected to a through hole (not shown) of a terminal fitting 7 fixed to the back surface of the insulating substrate 2 and electrically connected to an output electrode of a circuit pattern formed on the front surface 2a of the insulating substrate 2. Extends through it. The inner end 6a of the output terminal 6 is soldered to the terminal fitting 7, and the other lead wire 5b of the capacitor 5 is wound and connected to the inner end 6a after being wound.

Reference numeral 8 denotes a rubber terminal holding member formed by bending and forming a hard lead wire commonly called a piano wire.
The lead wire has a substantially circular cross section and a diameter of about 10 mm. As shown in detail in FIG. 2, the rubber terminal holding member 8 is fitted into a through hole formed in the insulating substrate 2 and is electrically connected to an input electrode of a circuit pattern formed on the surface 2a of the insulating substrate 2. One end 8a,
Extension 8b arranged along back surface 2b of insulating substrate 2
And an upright portion 8c extending from the extension 8b in a direction opposite to the one end 8a, and the other end 8d provided continuously with the upright portion 8c. The other end 8d is bent so as to form a substantially rectangular loop in a plane parallel to the back surface of the insulating substrate 2, and a conductive rubber terminal 9 is fitted in the loop. The length of the upright portion 8c is
As shown in FIG. 1A, an end 8d is located outside an insulating resin layer 10 formed by filling a soft epoxy-based insulating resin into a case opening 1d of the insulating case 1, and the end 8d is provided. The gap G filled with the mold resin is formed between the insulating resin layer 10 and the insulating resin layer 10 between the end face of the conductive rubber terminal 9 on the insulating substrate 2 and the insulating rubber layer 9. . From the upper wall 1e of the insulating case 1, an operating shaft 11 of a variable resistor for adjusting the focus voltage protrudes rotatably.

Since the lead wire used in this embodiment has a substantially circular cross section in the direction perpendicular to the axial direction, the contact area between the extension 8b and the back surface 2b of the insulating substrate 2 is small, and the insulating resin Of the insulating resin layer 10
There is no formation of a non-contact interface that may cause peeling of the substrate. Further, as in the present embodiment, when the cross-sectional shape in the axial direction of the lead wire has no corner, it is possible to prevent the insulating resin layer from cracking. As shown in FIG. 1B, in this embodiment, the lead wire 5a of the capacitor 5 crosses below the conductive rubber terminal 9, and the thickness of the insulating resin layer 10 is about 1 to 2 mm. The conductive rubber terminal 9 is positioned outside the insulating resin layer 10 because it is thin.
When the thickness of the insulating resin layer 10 is large, the conductive rubber terminals 9
May be located in the insulating resin layer 10.

The high-voltage variable resistor according to the above-described embodiment obtains an input from the intermediate output terminal of the flyback transformer.
Although the conductive rubber terminal 9 is arranged near the ground terminal 3, the position of the conductive rubber terminal naturally depends on the structure and mounting manner of the high-voltage variable resistor. Therefore, the shape of the rubber terminal holding member 8 also changes depending on the mounting position and the shape of the conductive rubber terminal 9. Even when the distance between the end portion 8a penetrating the insulating substrate 2 and the upright portion 8c becomes short, if the extension portion 8b that comes into contact with the back surface 2b of the insulating substrate 2 is provided, the molding resin hardens when cured. Since the force applied to the conductive rubber terminal 9 can be received by the extension,
No excessive force is applied to the connection between the end 8a and the input electrode. In the above embodiment, the extension 8b of the rubber terminal holding member 8 is arranged along the back surface 2b of the insulating substrate 2.
If the extension 81b is separated from the back surface 2b of the insulating substrate 2 as in the rubber terminal holding member 81 shown in FIG.
Separation of the insulating resin layer 10 can be reliably prevented. Note in this case, may be provided stopper portion 81a 1 performs the bending or pressing the edge portion 81a of the rubber terminal holding member 8. Further, as shown in a rubber terminal holding member 82 shown in FIG.
b.

In the above embodiment, the rubber terminal holding member is constituted by the lead itself for electrically connecting the circuit pattern formed on the surface 2a of the insulating substrate 2 and the conductive rubber terminal. Alternatively, a rubber terminal holding member may be configured. For example, as shown in FIG. 4, a central portion of one piano wire is wound around a conductive rubber terminal 9 ', and both ends thereof are fitted into mounting recesses provided on a pair of opposed walls of an insulating case 1'. A rubber terminal holding member 8 'having such a structure can be used. In FIG. 4, reference numeral 12 denotes connection terminals connected to a circuit pattern formed on the surface of the substrate 2 '. As shown in the example of FIG. 4, if the rubber terminal holding member 8 'is arranged away from the back surface of the insulating substrate 2', the non-contact interface between the insulating resin layer 10 'and the back surface of the insulating substrate 2' Since the rubber terminal holding member is not formed, any shape and structure can be adopted as long as the filling of the insulating resin is not hindered.

In the above embodiment, the present invention is applied to a single-axis type high-voltage variable resistor, but the present invention is also applied to a multi-axis type high-voltage variable resistor which can adjust both focus and screen. Of course, it can be applied.

[0027]

According to the first aspect of the present invention, it is possible to prevent peeling between the insulating substrate surface and the insulating resin layer, so that a creeping discharge is generated along the back surface of the insulating substrate. Can be prevented. Also, according to the present invention, the lead wire and
The cross section in the direction perpendicular to the axial direction has no corners.
Since it is almost circular, it is embedded in insulating resin.
Cracks in the insulating resin layer due to broken leads
There is an advantage that can be prevented.

According to the invention of claim 2, by holding the conductive rubber terminal so that a part of the conductive rubber terminal is located in the insulating resin layer formed by the insulating resin, the high-voltage variable resistor is provided. The overall thickness can be reduced.

According to the third aspect of the present invention, since the conductive rubber terminals are arranged apart from the insulating resin layer, the dielectric strength of the insulating resin layer does not decrease.

According to the invention of claim 4, since the rubber terminal holding member is constituted by the lead wire for electrically connecting the circuit pattern and the conductive rubber terminal, another component for fixing the conductive rubber terminal is provided. Since it becomes unnecessary, the number of parts can be reduced.

According to the invention of claim 5, even when the rubber terminal holding member is formed by using the lead wire, the conductive rubber terminal is not displaced in the direction orthogonal to the plate surface of the insulating substrate.
There is an advantage that the operation when filling the insulating resin with the conductive rubber terminal separated from the back surface of the insulating substrate is facilitated.

According to the invention of claim 6, the position of the conductive rubber terminal can be appropriately determined by appropriately changing the length and the bending direction of the lead wire.

[Brief description of the drawings]

FIGS. 1A and 1B are a partial sectional view and a bottom view, respectively, of an embodiment in which the present invention is applied to a high-voltage variable resistor used for adjusting a focus voltage of a cathode ray tube.

FIG. 2 is a diagram illustrating an example of a rubber terminal holding member.

FIGS. 3A and 3B are diagrams showing modified examples of the rubber terminal holding member.

FIG. 4 is a cross-sectional view for explaining another example of the rubber terminal holding member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Insulating case, 1d ... Opening, 2 ... Insulating board, 3, 4
... Earth terminal, 5 ... Capacitor, 6 ... Output terminal, 7 ... Terminal fitting, 8, 8 ', 81, 82 ... Rubber terminal holding member, 9
... conductive rubber terminals, 10 ... insulating resin layers, G: voids.

Claims (6)

(57) [Scope of request for utility model registration] 1. An insulating substrate provided with a circuit pattern including a resistor for a variable resistor on a front surface thereof is disposed in an insulating case having an opening at one end so that a back surface faces a case opening side, and the front surface of the insulating substrate is provided. A conductive rubber terminal electrically connected to the circuit pattern provided on the back surface side of the insulating substrate is held by a rubber terminal holding member, and the back surface of the insulating substrate is placed in the case opening of the insulating case. An insulating resin layer is formed by filling an insulating resin so as to cover the insulating resin layer, and the case opening side of the insulating case is fixed to a flyback transformer via a mold resin. The holding member holds the conductive rubber terminal so that the conductive rubber terminal is separated from the back surface of the insulating substrate and the insulating resin is interposed between the back surface and the back surface. , Moreover the feature that the cross-sectional shape so as not to form a non-contact interface such as to generate peeling is made by bending generally circular lead between the back of the insulating substrate and the insulating resin layer Variable resistor for high voltage. 2. The high-voltage variable resistor according to claim 1, wherein the rubber terminal holding member holds the conductive rubber terminal such that a part of the conductive rubber terminal is located in the insulating resin layer. . 3. The rubber terminal holding member holds the conductive rubber terminal so as to form a gap filled with the mold resin between the conductive rubber terminal and the insulating resin layer. 2. The high-voltage variable resistor according to 1. 4. The rubber terminal holding member has a sectional shape for electrically connecting the circuit pattern and the conductive rubber terminal.
2. The high-voltage variable resistor according to claim 1, wherein the high-voltage variable resistor has a substantially circular shape . 5. An end of the lead wire to which the conductive rubber terminal is attached is a lug into which the conductive rubber terminal is fitted.
The high-voltage variable resistor according to claim 4, wherein the high-voltage variable resistor is bent so as to form a loop. 6. The high-voltage variable resistor according to claim 5, wherein the lead wire has an extension extending along a back surface of the insulating substrate to position the conductive rubber terminal at a desired position. vessel.