JP2793987B2 - Electronic component unit for high voltage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-voltage electronic component unit in which a circuit board having high-voltage electronic components is housed in a synthetic resin insulating case.

[0002]

2. Description of the Related Art As a high voltage electronic component unit, for example, a high voltage resistor unit used for adjusting a high voltage circuit such as a focus circuit or a screen circuit of a cathode ray tube of a television is well known. FIG. 2 is a partially cutaway sectional view of a conventional high-voltage resistor unit used for adjusting a focus circuit and a screen circuit. In FIG. 1, reference numeral 1 denotes an opening-shaped insulating case formed by using a synthetic resin material such as Noryl resin (PPO), and reference numeral 2 denotes a circuit board housed and fixed in a housing recess 1a of the insulating case. On the circuit board 2, a resistor 3 for a fixed resistor such as a bleeder resistor and a resistor for a variable resistor (not shown) for the variable resistors 4 and 5 are formed by printing. Circuit board 2
Is a partition wall portion 1b provided in the storage recess 1a of the insulating case 1.
And is fixed to a mounting step (not shown) using an adhesive. Reference numeral 6 denotes an insulating resin layer formed by filling and thermosetting a thermosetting resin such as an epoxy resin. In this example, a first storage space 7 surrounded by an outer wall 1c of the insulating case 1, a portion of the circuit board 2 provided with the partition 1b and the resistor 3, a back surface of the circuit board 2 and the insulating case 1 And the space 8 surrounded by the peripheral wall of the opening is filled with an insulating resin. The insulating resin layer 6 is provided for the purpose of strengthening insulation. The second storage space 9 of the variable resistor in which the slider and the resistor (not shown) are stored is liquid-tight so that the insulating resin does not enter.

Further, a high voltage electronic component unit having an improved insulating performance by keeping the space for accommodating high voltage electronic components airtight without using an insulating resin layer as in the unit disclosed in Japanese Utility Model Publication No. 60-31210 has been developed. Have been.

[0004]

The high-voltage electronic component unit is used in various environments. However, recently, the high-voltage electronic component unit has a high ambient temperature and a high humidity over a long period of time such as a tropical region. This type of unit is also used in equipment used in places. Therefore, enhancement of the dielectric strength is strongly desired. However, the noryl resin used for the insulating case 1 in the conventional unit shown in FIG. 2 is relatively vulnerable to a temperature change, and cracks are easily generated in the insulating case 1. If air bubbles remain in the insulating resin layer 6, the air bubbles may cause cracks in the insulating resin layer 6. When a crack occurs, the dielectric strength decreases, and in the worst case, as shown by reference numeral 10 in FIG.
In some cases, a discharge may occur between the unit and the surface of the unit, and the unit may be broken. Even when the insulating resin layer 6 is not used, the same problem occurs if a crack occurs in the insulating case 1. Therefore, various attempts have been made to form the insulating case from a synthetic resin material that is resistant to temperature changes, and to keep air bubbles from remaining in the insulating resin layer 6 as much as possible. However, at present, there is no optimal synthetic resin material that is inexpensive, and it is extremely difficult to completely prevent bubbles from remaining in the insulating resin layer 6.

In order to solve such a problem, the inventor has made the insulating case a double structure including an inner case body and an outer case body, and insulated between the two case bodies so as to surround the inner case body. A method of forming a resin-filled space, filling the space with a thermosetting insulating resin, and curing the resin is considered to increase the dielectric strength. However, if the insulating resin filling space cannot be reliably formed, the withstand voltage cannot be sufficiently increased.

An object of the present invention is to provide a high-voltage electronic component unit capable of reliably increasing the dielectric strength.

[0007]

The basic idea of the present invention is that a circuit board provided with high-voltage electronic components is housed in a circuit board housing recess of an insulating case made of synthetic resin, and an opening of the circuit board housing recess is insulated. In the high-voltage electronic component unit sealed with resin, the insulating case made of synthetic resin has a double structure consisting of an inner case body and an outer case body, and the insulating resin is filled between the inner case body and the outer case body To form a reinforcing insulating resin layer. The reinforcing insulating resin layer may be formed simultaneously with the molding of another component such as a transformer provided adjacent to the unit. In this case, the insulating resin filling space formed between the inner case body and the outer case body has a shape that allows easy filling of the insulating resin.

[0008] The idea is that a thermosetting insulating resin is filled between a portion of a circuit board on which a fixed high-voltage electronic component is provided and an insulating case made of synthetic resin to form an insulating resin layer. In this case, a four-layer insulating structure of an insulating resin layer, an inner case body, a reinforcing insulating resin layer, and an outer case body is provided, and the dielectric strength is greatly improved.

The present invention particularly applies this concept to a high voltage electronic component unit used as a high voltage resistor unit used for adjusting a high voltage circuit such as a focus circuit and a screen circuit of a CRT of a television. In this case, the basic components of the high-voltage electronic component unit are a circuit board having a variable resistor on its surface, a slider having a contact sliding on the variable resistor, a circuit board and a slider. This is an open-type synthetic resin insulating case for accommodating the moving element. The synthetic resin insulating case has a double structure including an inner case body and an outer case body. A plurality of operation shaft holding portions for rotatably holding a plurality of operation shafts for operating a plurality of sliders are integrally formed on the inner case. Further, the plurality of operation shaft holding portions are fitted into a plurality of through holes formed in the outer case body, and open between the inner case body and the outer case body in the same direction as the circuit board housing concave portion, and the inner case body is formed. An insulating resin filling space filled with the insulating resin is formed so as to surround the periphery. The space filled with the insulating resin is filled with the insulating resin and cured to form the reinforcing insulating resin layer.

If the insulating case made of synthetic resin has a double structure of an inner case body and an outer case body and a reinforcing insulating resin layer is formed between the two case bodies, the case for accommodating the circuit board is made of the inner case body and the inner case body. It has a three-layer integrated structure in which the reinforcing insulating resin layer and the outer case body are laminated. Unless a very large force is applied from the outside, it is extremely rare that cracks occur across all the members forming the three-layer structure. Therefore, even if a crack occurs in any member of the inner case body, the reinforcing insulating resin layer, and the outer case body, as long as the other members fulfill the insulating function, the occurrence of discharge can be prevented, and the dielectric strength can be reduced. It can be greatly improved.

When an insulating resin layer is formed between the circuit board and the insulating case, a four-layer insulating structure is formed at that portion, so that the dielectric strength can be further improved. In the present invention, step portions are formed on the outer peripheral portions of the plurality of operation shaft holding portions so as to contact the peripheral edges of the plurality of through holes provided in the outer case body and support the outer case body. With this configuration, the outer case body is supported by the steps formed in the plurality of operation shaft holding portions, so that the insulating resin filling space can be reliably formed between the inner case body and the outer case body. If there is no such step, the fitting state of the operation shaft holding portion to the through hole varies. If the fitting state is too tight, the thickness of the insulating resin filling space becomes small, and in some cases, cracks may be formed around the operation shaft holding portion or the through hole of the outer case body. Conversely, if the fitting state is too loose, the thickness of the insulating resin filling space increases, but the insulating resin may leak from the through hole. When the step portion is provided as in the present invention, these problems do not occur. In addition, when there is only one operation shaft holding portion, the outer case body may be inclined and mounted around the operation shaft holding portion unless the spacer means is separately arranged. In some cases, no special spacer means need be provided.

When the present invention is applied to a case where the unit includes a variable resistor, the mechanical strength and the dielectric strength of the portion of the insulating case that houses the variable resistor can be greatly improved.

If the space filled with the insulating resin formed between the inner case body and the outer case body is opened in the same direction as the circuit board housing recess and is formed so as to surround the periphery of the inner case body, it is arranged adjacently. Insulating resin can be easily filled together with a mold of another electronic component such as a transformer.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a partial vertical sectional view of an embodiment in which the present invention is applied to a high-voltage variable resistor unit having two variable resistors for focus adjustment and screen adjustment of a cathode ray tube. In the figure, reference numeral 11 denotes an insulating case made of synthetic resin having a double structure molded using a noril resin. The insulating case 11 includes an outer case body 12 and an inner case body 13. The inner case body 13 has a circuit board housing recess 13a into which the circuit board 14 is inserted at one end.
It is an open case body having
On the inner wall portion, a partition portion for forming a storage space for storing the sliders of the variable resistors 15 and 16 and the resistor for the variable resistor, and a mounting step portion for fixing the circuit board 14 are formed. ing. The circuit board 14 is formed by printing a resistor pattern and a circuit pattern on a high-voltage board made of alumina porcelain or the like. Also, the inner case body 13 has an operation shaft holder 1 for rotatably holding the operation shafts 15a and 16a of the variable resistors 15 and 16 and pulling the operation shafts 15a and 16a to the outside.
3b and 13c are integrally formed. As shown in the drawing, stepped portions 13b1 and 13c1 are formed on the outer peripheral portions of the operation shaft holding portions 13b and 13c.

The outer case body 12 is an open case formed to be larger than the inner case body 13, and the outer case body 12 is provided with airtight operation shaft holders 13b and 13c provided on the inner case body 13. Alternatively, through holes 12a and 12b are formed to penetrate and fit in a liquid-tight manner. An insulating resin filling space filled with a thermosetting resin such as an epoxy resin is formed between the inner case body 13 and the outer case body 12. In this embodiment, the through hole 12 of the outer case body 12 is provided.
Since the operation shaft holding portions 13b and 13c are fitted to a and 12b, and the outer case body 12 and the inner case body 13 are integrated, the space between the two case bodies can be surely provided without providing any spacer means. An insulating resin filling space can be formed. The space filled with the insulating resin is the inner case body 13.
Is formed so as to substantially surround the entire periphery of the outer wall portion of the
The opening is formed so as to surround the periphery of the opening of the inner case body 13.

A thermosetting resin is filled and hardened in an insulating resin filling space formed between the inner case body 13 and the outer case body 12 to form a reinforcing insulating resin layer 17.
A first housing space for housing a fixed resistor 18 such as a bleeder resistor provided on the circuit board 14 like the conventional unit of FIG. 2, a back surface of the circuit board 14 and the inner case 1
The space surrounded by the peripheral wall of the opening 3 is filled with a thermosetting resin such as an epoxy resin and cured, and an insulating resin layer 19 is provided between the circuit board 14 and the inner case body 13.
Are formed. Reference numeral 20 denotes a conductive terminal fitting electrically connected to the circuit pattern of the circuit board 14.

According to the above unit, the four-layer insulating structure of the insulating resin layer 19, the inner case body 13, the reinforcing insulating resin layer 17, and the outer case body 12 is provided on the fixed resistor 18 to which the highest voltage is applied. Are formed. Further, a three-layer insulating structure of the inner case body 13, the reinforcing insulating resin layer 17, and the outer case body 12 is formed on the portion where the variable resistors 15 and 16 are housed. Therefore, according to the present embodiment, not only can the mechanical strength of the entire case be increased, but even if a crack occurs in some members of the laminated insulating structure, the circuit board can be immediately passed through the crack. No discharge occurs between the high-voltage portion on 14 and the outer surface of the case. In a unit provided with a variable resistor, the resistor for the variable resistor cannot be covered with an insulating resin. However, if the case portion accommodating the variable resistors 15 and 16 has a three-layer insulating structure as in this embodiment, The strength and dielectric strength of this part can be greatly improved.

In order to confirm the effect of the present invention, a crack 21 is formed in the insulating resin layer 19, a conductive paint is applied to the outer surface of the outer case body 12 to form a ground layer, and a ground layer is formed. An experiment was performed by applying a voltage of 20 kV to 100 kV to the circuit pattern, but no discharge occurred.

In the above embodiment, the insulating resin layer 19 is formed between the inner case body 13 and the portion of the circuit board 14 on which the fixed resistor 18 as the fixed high-voltage electronic component is provided. Of course, the present invention can also be applied to a high-voltage electronic component unit in which an insulating resin layer is not formed in an inner case. Although the above embodiment is a unit having a variable resistor, the present invention can of course be applied to a unit having no variable resistor.

When the unit of the above embodiment is used integrally with a flyback transformer, the reinforcing insulating resin layer 17 is molded together with the flyback transformer.
May be formed.

The above embodiment is an example in which the present invention is applied to a high-voltage resistor unit. However, the subject of the present invention is not limited to the above-described embodiment, and the present invention can be applied to various high-voltage electronic component units. Can be applied.

[0022]

According to the present invention, when the outer case body is supported by the steps formed on the plurality of operation shaft holding portions,
There is an advantage that an insulating resin filling space can be reliably formed between the inner case body and the outer case body.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of an embodiment when the present invention is applied to a high-voltage variable resistor unit.

FIG. 2 is a partial longitudinal sectional view showing an example of a conventional unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating case 2,14 Circuit board 3,18 Fixed resistor (high-voltage electronic component) 4,5,15,16 Variable resistor 6,19 Insulating resin layer 11 Synthetic resin insulating case 12 Outer case body 12a, 12b Through hole 13 Inner case body 13a Circuit board housing recess 13b, 13c Operation shaft holder 13b1, 13c1 Step 17 Reinforcement insulating resin layer

Claims (2)

(57) [Claims] 1. A circuit board provided with a plurality of variable resistor resistors on a surface, a plurality of sliders having contacts sliding on the plurality of variable resistor resistors, the circuit board, and An open-type synthetic resin insulating case provided with a circuit board housing recess for housing the slider, wherein the synthetic resin insulating case has a double structure including an inner case body and an outer case body, A plurality of operation shaft holding portions for rotatably holding a plurality of operation shafts for operating the plurality of sliders are integrally formed on the inner case body, and the plurality of operation shaft holding portions are formed on the outer case. An insulating resin that is fitted into a plurality of through holes formed in the body and that opens between the inner case body and the outer case body in the same direction as the circuit board housing recess and surrounds the inner case body; Is filled with insulating resin filling space is formed In the electronic component unit for high voltage, a step portion is formed on an outer peripheral portion of the plurality of operation shaft holding portions, the step portion supporting the outer case body in contact with a peripheral edge portion of the plurality of through holes. High voltage electronic component unit. 2. The high-voltage electronic component unit according to claim 1, wherein the inner case body and the outer case body are formed using a noril resin.