JPH0851006A - High voltage electronic device unit - Google Patents

Abstract

PURPOSE:To enhance dielectric strength surely by employing a synthetic resin insulating case having double structure of inner and outer cases and filling the gap between the inner and outer cases with an insulating resin to form an insulating resin layer for reinforcement. CONSTITUTION:An insulating case 11 is constituted of inner and outer case bodies 13, 12. The inner case body 13 is an open case body having a recess 13a for receiving a circuit board 14 at one end thereof. A barrier wall part forming a space for containing the sliders and resistors of variable resistors 15, 16 is formed at the inner wall part of the inner case body along with a step part for fixing the circuit board 14. The outer case body 12 is provided with through holes 12a, 12b for passing the operating shaft holding parts 13b, 13c on the inner case body 13 airtightly or liquid-tightly. The space between the inner and outer case bodies 13, 12 is filled with a thermosetting resin which is eventually set to form an insulating resin layer 17 for reinforcement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 and a screen circuit of a cathode ray tube of a television is well known. FIG. 2 shows a partially cutaway sectional view of a conventional high voltage resistor unit used for adjusting a focus circuit and a screen circuit. In the figure, 1 is an opening type insulating case molded using a synthetic resin material such as Noryl resin (PPO), and 2 is a circuit board housed and fixed in a housing recess 1a of the insulating case. On the circuit board 2, a fixed resistor resistor 3 such as a bleeder resistor and a variable resistor 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.
It is fixed to the mounting step portion (not shown) using an adhesive. Reference numeral 6 is an insulating resin layer formed by filling a thermosetting resin such as an epoxy resin and thermosetting. In this example, the first housing space 7 surrounded by the outer wall portion 1c of the insulating case 1, the partition wall portion 1b and the portion of the circuit board 2 on which the resistor 3 is provided, the back surface of the circuit board 2 and the insulating case 1 The insulating resin is filled in the space 8 surrounded by the peripheral wall of the opening. The insulating resin layer 6 is provided for the purpose of strengthening insulation. The second accommodating space 9 for accommodating a slider and a resistor (not shown) of the variable resistor is liquid-tight so that the insulating resin does not enter.

Also, unlike the unit disclosed in Japanese Utility Model Publication No. 60-31210, a high-voltage electronic component unit has been developed in which the storage space for high-voltage electronic components is kept airtight without using an insulating resin layer to improve the insulation performance. Has been done.

[0004]

The high-voltage electronic component unit is used in various environments, but recently, such as in tropical regions, where the ambient temperature becomes high temperature and high humidity for a long period of time. Units of this type are also used for equipment used in places. Therefore, it is strongly desired to strengthen the dielectric strength. However, the noryl resin used for the insulating case 1 in the conventional unit shown in FIG. 2 is relatively weak against temperature changes, and cracks easily occur in the insulating case 1. If bubbles remain in the insulating resin layer 6, the bubbles 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.
The unit may be destroyed due to discharge between the unit and the surface of the unit. Even if the insulating resin layer 6 is not used, if the insulating case 1 is cracked, the same problem occurs. Therefore, various attempts have been made to form the insulating case with a synthetic resin material that is resistant to temperature changes and to prevent bubbles from remaining in the insulating resin layer 6 as much as possible. However, at present, there is no optimum one among the inexpensive synthetic resin materials, and it is extremely difficult to completely leave no bubbles in the insulating resin layer 6.

In order to solve such a problem, the inventor has adopted an insulating case having a double structure consisting of an inner case body and an outer case body, and insulating the inner case body so as to surround the inner case body between the two case bodies. It was considered to form a resin-filled space, and to fill the space with a thermosetting insulating resin and cure it to increase the dielectric strength. However, if the insulating resin filled space cannot be reliably formed, the withstand voltage cannot be sufficiently increased.

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

[0007]

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

The idea is that a thermosetting insulating resin is filled between the portion of the circuit board on which the fixed high-voltage electronic component is provided and the insulating case made of synthetic resin to form an insulating resin layer. It can also be applied to a high-voltage electronic component unit, and in this case, it has a four-layer insulation structure of an insulating resin layer, an inner case body, a reinforcing insulating resin layer, and an outer case body, and the dielectric strength is greatly improved.

The present invention applies this idea particularly 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 cathode ray tube of a television. In that case, the basic elements of the high-voltage electronic component unit are a circuit board having a variable resistor resistor on its surface, a slider having a contact sliding on the variable resistor resistor, a circuit board and a slider. It is an opening type synthetic resin insulation case that houses the pendulum. The synthetic resin insulation case has a double structure consisting of an inner case body and an outer case body. A plurality of operation shaft holding portions that rotatably hold a plurality of operation shafts that operate a plurality of sliders are integrally formed in the inner case. Further, the plurality of operation shaft holding portions are fitted into the plurality of through holes formed in the outer case body, and are opened between the inner case body and the outer case body in the same direction as the circuit board accommodating recessed portion. An insulating resin filling space filled with the insulating resin is formed so as to surround the periphery. The insulating resin filling space 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 both case bodies, the case for housing the circuit board becomes the inner case body. The reinforcing insulating resin layer and the outer case body are laminated to form a three-layer integrated structure. Unless a very large force is applied from the outside, it is extremely rare for a crack to 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 insulating resin layer for reinforcement, and the outer case body, as long as the other members perform the insulating function, it is possible to prevent the occurrence of discharge and to improve the dielectric strength. It can be greatly improved.

When the insulating resin layer is formed between the circuit board and the insulating case, a four-layer insulating structure is formed in that portion, so that the dielectric strength can be further improved. In the present invention, the outer peripheral portions of the plurality of operation shaft holding portions are respectively formed with stepped portions that come into contact with the peripheral portions of the plurality of through holes provided in the outer case body to support the outer case body. With this configuration, the outer case body is supported by the step portions formed on the plurality of operation shaft holding portions, so that the insulating resin filled space can be reliably formed between the inner case body and the outer case body. If there is no such stepped portion, the fitting state of the operation shaft holding portion in the through hole varies. If the fitting state is too tight, the thickness of the insulating resin filled space becomes small, and in some cases, cracks may occur around the operation shaft holding portion or the through hole of the outer case body. On the other hand, if the fitting state is too loose, the insulating resin filling space will be thick, 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. Further, in the case where there is one operation shaft holding portion, if the spacer means is not separately arranged, the outer case body may be attached while being tilted about the operation shaft holding portion. In some cases, special spacer means may not be provided.

If a structure is adopted in which the end of the inner case body on the opening side is projected from the opening of the outer case body, the fitted state of the inner case body and the outer case body is set to the inside from the opening portion of the outer case body. By looking at the protruding state of the case body,
It can be easily inspected.

When a noryl resin is used as the synthetic resin used to form the inner case body and the outer case body, the inner case body and the outer case body are filled even when the insulating resin filled space is filled with the insulating resin and cured. Body deformation is reduced and yield is improved.

When the present invention is applied to the case where the unit includes the variable resistor, the mechanical strength and the dielectric strength of the portion of the insulating case which accommodates the variable resistor can be significantly improved.

If the insulating resin filling space formed between the inner case body and the outer case body is formed so as to open in the same direction as the circuit board accommodating recess and surround the inner case body, they are arranged adjacent to each other. The insulating resin can be easily filled together with the molding of other electronic components such as transformers.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below 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 including two variable resistors for focus adjustment and screen adjustment of a cathode ray tube. In the figure, reference numeral 11 is a double-structured synthetic resin insulating case molded using a noryl resin. The insulating case 11 is composed of 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 opening type case body having a
On the inner wall portion, a partition wall portion for forming a storage space for storing the sliders of the variable resistors 15 and 16 and the variable resistor resistor body, 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. Further, the inner case body 13 has an operation shaft holding portion 1 for rotatably holding the operation shafts 15a and 16a of the variable resistors 15 and 16 and pulling them out.
3b and 13c are integrally formed. As shown in the figure, the operation shaft holding portions 13b and 13c are provided with step portions 13b1 and 13c1 on their outer peripheral portions.

The outer case body 12 is an opening-shaped case body formed to be larger than the inner case body 13, and the outer case body 12 is hermetically sealed with operation shaft holding portions 13b and 13c provided on the inner case body 13. Alternatively, through holes 12a and 12b are formed which are fitted so as to penetrate liquid-tightly. 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 the present embodiment, the through hole 12 of the outer case body 12
Since the operation shaft holding portions 13b and 13c are fitted to the a and 12b, and the outer case body 12 and the inner case body 13 are integrated, it is possible to surely provide the space between both case bodies without providing spacer means. An insulating resin filled space can be formed. The insulating resin filling space is the inner case body 13.
Is formed so as to substantially surround the entire outer wall of the
The opening is provided so as to surround the opening of the inner case body 13.

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

According to the above unit, the four-layer insulation 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. In addition, a three-layer insulating structure including an inner case body 13, a reinforcing insulating resin layer 17, and an outer case body 12 is formed on the portion where the variable resistors 15 and 16 are housed. Therefore, according to this embodiment, not only can the mechanical strength of the entire case be increased, but also when a crack occurs in a part of the laminated insulating structure, the circuit board is immediately passed through the crack. No discharge occurs between the high voltage part on 14 and the outer surface of the case. In the unit including the variable resistor, the variable resistor resistor cannot be covered with the insulating resin, but if the case portion accommodating the variable resistors 15 and 16 has a three-layer insulating structure as in the present embodiment, The strength and dielectric strength of this portion 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 the ground layer is formed on the circuit board 14. An experiment was conducted 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 which is a fixed high voltage electronic component is provided. Can naturally be applied to a high-voltage electronic component unit of a type in which an insulating resin layer is not formed in the inner case. Further, although the above-mentioned embodiment is a unit provided with a variable resistor, the present invention can of course be applied to a unit not provided with a variable resistor.

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

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

[0024]

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

[Brief description of drawings]

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulation 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 Storage Recess 13b, 13c Operation Shaft Holding Section 13b1, 13c1 Stepped Section 17 Reinforcing Insulating Resin Layer

Claims (3)

[Claims] 1. A circuit board having a plurality of variable resistor resistors on its surface, a plurality of sliders having contacts sliding on the variable resistor resistors, the circuit board, and An insulating synthetic resin case having an opening shape having a circuit board housing recess for housing the slider is provided, and 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 that rotatably hold a plurality of operation shafts that operate the plurality of sliders are integrally formed in the inner case body, and the plurality of operation shaft holding portions are the outer case. It is fitted into a plurality of through-holes formed in the body, and an insulating resin is formed between the inner case body and the outer case body in the same direction as the circuit board accommodating recess so as to surround the inner case body. Insulating resin filling space filled with In the high-voltage electronic component unit according to claim 1, stepped portions that contact the peripheral portions of the plurality of through holes and support the outer case body are formed on outer peripheral portions of the plurality of operation shaft holding portions, respectively. High-voltage electronic component unit. 2. An electronic component unit for high voltage, characterized in that an end of the inner case body on the opening side projects from the opening of the outer case body. 3. The high voltage electronic component unit according to claim 1, wherein the inner case body and the outer case body are molded using a noryl resin.