JP3159958B2 - Flyback transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CRT (Cathod).
The present invention relates to a flyback transformer having a high-voltage resistor pack in which a variable resistor for adjusting a focus voltage of a Ray Tube (cathode ray tube) is housed in an insulating case.

[0002]

2. Description of the Related Art Generally, a high voltage resistor pack of a flyback transformer provided with a high voltage resistor pack provided with a variable resistor for adjusting a focus voltage of a CRT or a screen voltage usually has a high voltage of 8 kV to 30 kV. Has been applied.
Therefore, in order to prevent discharge inside and outside the case,
As disclosed in -32721, after the circuit board on which the resistor is formed is accommodated in the case of the high-voltage resistor pack, the opening of the case is filled with insulating resin so as to fill the circuit board. And sealed to prevent discharge inside and outside the case. Then, such a high-voltage resistance pack is attached to the case of the flyback transformer using an engagement structure.

[0003]

In the case of the above-mentioned prior art, when cracks occur in the case of the high-voltage resistance pack or the insulating resin due to a temperature change or bubbles remaining in the insulating resin, The pressure resistance performance of that part is significantly reduced.

[0004] In addition, materials that are unlikely to cause cracks are extremely expensive and are not suitable for mass-produced products.
Bubbles cannot be completely suppressed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has as its object to provide a flyback transformer which has a high withstand voltage performance even if a crack occurs in a case of a high-voltage resistance pack and which is relatively inexpensive. Aim.

[0006]

According to the present invention, a high-voltage resistor pack having a circuit board 3 provided with a variable resistor on the surface is provided as a case 1 of the present invention. The engaging edge 5a formed on the edge of the outer wall 5 is engaged with the engaging portion 11 of the case 10a of the flyback transformer 10.
And a flyback transformer attached to the flyback transformer case 10a.

In the present invention, the case 1 of the high-voltage resistance pack is used.
Around the relatively high voltage area of the circuit board,
A partition wall 6 protruding from the inner surface of the case 1 higher than the installation position of the circuit board 3 is provided in parallel with the outer wall 5 of the case 1,
A groove 8 is formed between the outer wall 5 and the partition 6 of the case 1 to surround a portion of the circuit board to which a relatively high voltage is applied.

According to the present invention, the groove provided in the case of the high-voltage resistance pack is filled with insulating resin for filling the flyback transformer, and the insulating resin wall is formed around a portion of the circuit board to which a relatively high voltage is applied. To form In this case, the outer wall 5, the insulating resin wall, and the partition wall 6 of the case 1 surround the portion of the circuit board to which a relatively high voltage is applied, so that the case 1 is used during assembly. Even if cracks occur on the outer wall 5, the pressure resistance performance is not impaired. In particular, since the resin filled in the flyback transformer is a hard resin having excellent moisture resistance, the insulating resin filled in the groove 8 forms a strong insulating resin wall having excellent moisture resistance. In particular, as in the present invention, when the groove 8 extends completely along three sides surrounding a portion to which a relatively high voltage is applied to the circuit board 3 , the groove 8 has a strong and humidity resistance including a low voltage portion. Because it can be surrounded by excellent insulating resin walls,
The pressure resistance becomes very high.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 4 show a first embodiment of the present invention. A flyback transformer having a high-voltage resistor pack according to this embodiment is used for adjusting a focus voltage and a screen voltage of a CRT. The case 1 of the high-voltage resistance pack is a box body having one side of a hexahedron opened, and an adjustment knob 2 for adjusting a resistance value by moving a slider 2a of a variable resistor on a surface opposite to the opening. Is attached.

In the case 1, a circuit board 3 on which a resistor pattern including a variable resistor for adjusting a focus voltage and a screen voltage is printed is provided with a board mounting portion 4 for determining an installation position of the circuit board. The slider mounted on and adhered to the adjustment knob 2 slides on the resistor. The substrate mounting portion 4 is formed on the inner surface of a partition 6 protruding into the case 1 in parallel with the outer wall 5 of the case 1 of the circuit board 3. It is provided so as to completely surround, that is, to extend completely along three adjacent sides. Therefore, a groove 8 is formed between the partition 6 and the outer wall 5 along three sides of the case 1. As shown in FIG. 2 to FIG. 4, the groove 8 extends beyond the substrate
Extends to the inner surface side.

FIG. 4A shows the inner surface of the case 1.
As shown in FIG. 2, a plurality of protrusions 4a that come into contact with the central portion of the circuit board 3 are formed to protrude from the inner surface of the case 1.
As shown in FIG. 4A, the projection 4a is
Are provided to form a slit at predetermined intervals diagonally to each other, to increase the spatial distance between the variable resistors, to prevent creeping discharge, and to increase the mechanical strength of the case 1. is there.

Further, inside the case 1 where the terminals 7 of the circuit board 3 are located, an arc-shaped portion 4b is formed so as to surround the terminals 7, and the circuit board 3 is placed around the terminals 7 of the circuit board 3. are doing.

Terminals 7 are provided at four corners of the circuit board 3, and project from the opening of the case 1. Then, a portion surrounded by the arc-shaped portion 4b and the partition 6 of the case 1 is filled with an insulating resin 9, and furthermore, each input / output terminal 7 of the circuit board 3 on the opening side of the case 1 protrudes. On the side, an insulating resin 9 such as an epoxy resin is poured from the opening side of the case 1 in a state where the circuit board 3 is mounted in the case 1. As a result, the insulating resin layer 9 completely sealing the inner surface of the circuit board 3 where the resistor is formed is provided.
“a” is formed in the opening of the case 1 to ensure the insulation between the inside and the outside.

Further, the high voltage resistance pack is integrally attached to the flyback transformer 10. An engagement portion 11 is formed on a case 10a of the flyback transformer 10, and an engagement edge 5a formed on an edge of the outer wall 5 of the case 1 of the high-voltage resistance pack is engaged with the engagement portion 11 so as to engage the both. Is connected. And flyback transformer 10
In the case 10a, an epoxy resin (for example, TCG1186 manufactured by Toshiba Chemical Co., Ltd.) which is hard and excellent in humidity resistance is provided.
And the like. At this time, the insulating resin 12 is also filled in the groove 8 of the case 1, and the high-voltage resistance pack and the flyback transformer 10 are integrated. As shown in FIG. 3, the engaging edge 5a of the case 1 of the high-voltage resistance pack and the engaging portion 1 of the case 10a of the flyback transformer.
The structure for engaging with 1 is such that the engaging portion 11 does not greatly enter the inside of the groove 8 and prevent the groove 8 from being filled with the insulating resin 12, that is, the groove 8 is not narrowed. Therefore, the wall of the insulating resin 12 can be reliably formed in the groove 8.

Next, a method of manufacturing a flyback transformer according to the present invention will be described with reference to FIG.

First, as shown in FIG.
An adhesive 13 is applied to the upper surface of the substrate mounting portion 4 and the protrusions 4a, and a portion surrounded by the arc-shaped portion 4b and the partition 6 is filled with the insulating resin 9 as shown in FIG. Here, the adhesive 13 may be a thermosetting resin. And projection 4
Due to the slit between a, air flow is improved, and the adhesive and the resin are easily cured.

Next, as shown in FIG. 4C, the circuit board 3 is placed on the substrate placing portion 4, the projection 4a, and the arc-shaped portion 4b, and as shown in FIG. The insulating resin 9 is poured from above the circuit board so that the board 3 is filled. The insulating resin 9 is cured at a temperature of about 100 ° C. for 3 to 3.5 hours by removing bubbles in the resin in a vacuum of 15 mmHg or less after casting. Thus, the circuit board 3 is completely buried in the insulating resin 9 to achieve insulation.

Thereafter, as shown in FIG. 4 (E), it is attached to the flyback transformer 10 and inside the case 10a of the flyback transformer 10, the case 10a of the flyback transformer 10 and the case 1 of the high-voltage resistance pack. The gap 8 and the groove 8 are simultaneously filled with an insulating resin 12 such as a hard and highly moisture-resistant epoxy resin for sealing the flyback transformer in a vacuum, and then defoamed and hardened.

According to the flyback transformer of this embodiment, the entire circuit board 3 to which a high voltage is applied is covered with the insulating resin 9 and the flyback transformer 1
Since the insulating resin 12 for sealing is filled in the groove 8, even if a part of the case 1 is cracked, the crack does not reach the vicinity of the circuit board 3 and the insulating property is improved. There is no loss. Furthermore, when sealing the flyback transformer 10, the insulating resin 1
Since 2 is filled, it is possible to easily fill the narrow groove 8 without increasing the number of steps.

Further, the slit formed by the projection 4a in the case 1 increases the spatial distance between the variable resistors and reduces the potential gradient, so that creeping discharge can be effectively prevented. Further, the strength of the case 1 is increased by the projections 4a in the case 1, and the expansion and contraction of the circuit board 3, the shrinkage of the cast insulating resin 9 at the time of curing, and the expansion and shrinkage due to a subsequent temperature change are countered. This makes it difficult for the case 1 to crack.

Next, another example will be described with reference to FIGS. Here, the same members as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In this example, the high-voltage resistor pack attached to the flyback transformer 10 has a partition wall 6 only on the side where the focus circuit for applying a relatively higher voltage is formed.
Are provided in the case 1.

As a result, it is possible to minimize the size of the case, minimize the design change on the flyback transformer side, and use a conventional one.

Next, the example of FIG. 8 will be described. Here, the same members as those in the above-described example are denoted by the same reference numerals, and description thereof will be omitted.

In the high-voltage resistance pack used in this example, the ridge 15 traversing the circuit board 3 is formed by curving the outer surface of the case 1.
6 are formed and face the circuit board 3 with a slight gap. The surface of the resistor 3 a on the circuit board 3 is coated with a glass or resin coat 18, and the insulating resin 17 filled in the recess 16 is connected to the ridge on the surface of the circuit board 3. 3 prevents discharge on the surface.

The arc-shaped portion 19 surrounding the mounting portion of the terminal 7 is also formed by bending the case 1.

According to this example, discharge in the case 1 can be reliably prevented by the insulating resin 17 at the tip of the ridge 15.

It should be noted that the present invention can utilize a focus circuit only, or a high-voltage resistance pack having a capacitor or the like mounted in a case.

According to the flyback transformer of this embodiment, a partition is formed inside the case along the side wall of the case to which a high voltage is applied, and a groove is formed between the partition and the outer wall of the case.
Since the insulating resin for sealing the flyback transformer other than the insulating resin filling the circuit board is filled, even if a crack enters the case or a part of the insulating resin, the crack penetrates between the circuit board and the external space. And insulation is not impaired.

[0030]

According to the present invention, the insulating resin for filling the flyback transformer is filled in the groove surrounding the portion of the circuit board provided in the case of the high-voltage resistance pack to which a relatively high voltage is applied. The outer wall of the case of the high-voltage resistance pack, the wall of the insulating resin filled in the groove and the partition wall can surround the portion of the circuit board to which a relatively high voltage is applied. Therefore, there is an advantage that even if a crack occurs on the outer wall of the case of the high-voltage resistance pack during use after assembling, the pressure resistance performance is not impaired. In particular,
Since the resin filled in the flyback transformer is a hard resin having excellent moisture resistance, the insulating resin filled in the groove forms a strong insulating resin wall having excellent moisture resistance. In particular
According to the present invention, since the groove is formed so as to extend completely along three sides surrounding a portion to which a relatively high voltage is applied to the circuit board , the groove is strong and excellent in humidity resistance including the portion where the voltage is low. and Ki de be enclosed in the walls of the insulating resin, the withstand voltage performance is very high.

[Brief description of the drawings]

FIG. 1 is a front view of an example of a high voltage resistance pack used in a flyback transformer of the present invention.

FIG. 2 is a partially cutaway right side view of the high-voltage resistance pack of FIG. 1;

FIG. 3 is a cross-sectional view showing a state in which a flyback transformer is attached to a cross section taken along line AA of FIG. 1;

FIGS. 4A to 4E are explanatory diagrams showing the manufacturing steps of the flyback transformer of the present embodiment.

FIG. 5 is a front view of another example of a high-voltage resistance pack.

FIG. 6 is a partially broken right side view of the high voltage resistance pack of FIG. 5;

FIG. 7 is a sectional view taken along the line BB of FIG. 5;

FIG. 8 is a cross-sectional view of another example of a high-voltage resistance pack.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 3 Circuit board 4 Board mounting part 5 Outer wall 6 Partition wall 7 Terminal 8 Groove 9, 12 Insulating resin 10 Flyback transformer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-256202 (JP, A) JP-A-60-71110 (JP, U) JP-A-59-161608 (JP, U) JP-A-56 67703 (JP, U) Actually open sho 64-16611 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01C 13/00 H01C 1/034 H01F 38/42 H05K 1/16

Claims (1)

(57) [Claims] 1. A high-voltage resistance pack having a circuit board provided with a variable resistor on a surface thereof has an engaging edge formed on an edge of an outer wall of the case. the engagement portion of the case (10a) of the flyback transformer (10) (11) is engaged is attached to the flyback transformer of the case (10a), the prior SL high voltage resistor packs case (1), A partition wall (6) surrounding a portion of the circuit board to which a relatively high voltage is applied and projecting from an inner surface of the case (1) above the installation position of the circuit board (3) is provided in the case (1). A groove (8) provided in parallel with the outer wall (5) and surrounding the portion of the circuit board to which the relatively high voltage is applied is provided between the outer wall (5) of the case (1) and the partition (6). The flyback transformer case (1) In the insulating resin (12) is flyback transformer that is filled in the groove (8) which is filled in a) to seal the interior, said groove (8), said circuit board of said circuit board (3)
The three sides surrounding the part where relatively high voltage is applied completely
A flyback transformer characterized by extending along .