JP3046131B2 - Dry capacitor with built-in discharge 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 dry capacitor with a built-in discharge resistor which has a gap between a discharge resistor and a resin mold to stabilize quality and improve reliability.

[0002]

2. Description of the Related Art FIGS. 2A and 2B show a conventional dry capacitor with a built-in discharge resistor. FIG. 2A is an internal circuit diagram, FIG. 2B is an enlarged explanatory view of the discharge resistor, and FIG.
One or more capacitor elements 22 and discharge resistors 23
The mainstream structure is such that (for example, a carbon film fixed resistor) is connected in parallel by a lead wire 24 coated with silicon, and a thermosetting resin such as an epoxy resin or a polyester resin is cast and a resin mold 25 is formed. Reference numeral 26 denotes an external lead-out terminal connected to the lead wire 24.

[0003]

However, the dry capacitor with a built-in discharge resistor having the above-mentioned structure has a problem that the thermosetting resin is cured by heat and contraction, and the thermal expansion and contraction between the thermosetting resin and the discharge resistor. The cracks on the surface of the discharge resistor due to the stress caused by the difference in the rate cause a problem that the withstand voltage performance of the discharge resistor deteriorates and the resistance value changes.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dry capacitor with a built-in discharge resistor which has solved the above-mentioned problems. That is, the one or a plurality of capacitor elements discharge resistor in parallel connection, in the discharge resistor built dry capacitor formed by resin molding and a release agent is interposed between the discharge resistor and the resin molding resin A dry capacitor with a built-in discharge resistor, wherein the gap is formed between the discharge resistor and the resin mold by molding.

[0005]

The structure in which the gaps are formed as described above prevents direct contact between the discharge resistor and the resin mold, and avoids physical stress such as heat curing shrinkage of the mold resin and thermal cycle deformation. it can.

[0006]

FIG. 1 shows a dry capacitor with a built-in discharge resistor according to the present invention.
An example will be described. 1A is an internal circuit configuration diagram, FIG. 1B is an enlarged view of a main part, 11 is a dry capacitor with a built-in discharge resistor, 12 is one or more capacitor elements, and 13 is a carbon film fixed resistor. Discharge resistor, 14
Is a lead wire coated with a release agent such as silicon, 15 is a resin mold cast with a thermosetting resin such as an epoxy resin or a polyester resin, 16 is an external lead-out terminal, 17 is a fluorine-based release agent, 18 is This is a gap formed between the resin mold 15 and the discharge resistor 13.

The dry capacitor 11 with a built-in discharge resistor is
One or a plurality of capacitor elements 12 and a discharge resistor 13 coated with a fluorine-based release agent 17 on the entire surface are connected in parallel with a lead wire 14, and an external lead terminal 16 is connected to the end of the lead wire 14. And housed in a casting mold (not shown)
After vacuum drying, a thermosetting resin, such as an epoxy resin or a polyester resin, was injected into the casting mold, heated and cured to form a resin mold 15, and then removed from the casting mold to complete the production.

In the manufactured dry capacitor 11 with a built-in discharge resistor, a fluorine-based release agent 17 was applied to the entire surface of the discharge resistor 13 as described above.

In the dry capacitor 11 with a built-in discharge resistor of the embodiment shown in FIG. 1, a fluorine-based release agent 17 is applied to the discharge resistor 13 to form gaps 18 respectively.
8, the discharge resistor 13 and the resin mold 15 can be prevented from directly contacting each other, and physical stress such as thermal curing shrinkage and thermal deformation during a thermal cycle test can be avoided.

Further, since the connection lead 14 is coated with a release agent such as silicon, it is possible to prevent the resin from entering the lead wire due to surface tension.

Next, the discharge resistor 1 shown in FIG.
3 was subjected to the following thermal shock test for the dry capacitor B with a built-in discharge resistor of the present invention in which the gap 18 was formed by applying a fluorine-based release agent 17 and the conventional dry capacitor C with a built-in discharge resistor shown in FIG. , Then the AC voltage of 3810V
The resistance value after the thermal shock test is more than the specified value from −5% to +
Table 1 shows the results of the determination as to whether or not the range of 5% was satisfied.

[0012]

[Table 1]

As is clear from Table 1, the number of non-defective products in which the resistance value after the test satisfies the specified value range of -5% to + 5% with respect to the resistance value before the test is the conventional dry capacitor C with a built-in discharge resistor. In the case of, the test condition decreases sharply as the test condition becomes more severe. However, in the case of the dry capacitor B with a built-in discharge resistor of the present invention, even if the test condition becomes severe, 9 or 10 out of the 10 tests are good. , Hardly decrease.

Therefore, the dry capacitor B with a built-in discharge resistor of the present invention has a better thermal shock than the conventional dry capacitor C with a built-in discharge resistor, and the improvement effect is remarkable.

[0015]

As described above, in the dry capacitor with a built-in discharge resistor of the present invention, the discharge resistor is housed in an insulating container, and a fluorine-based release agent is interposed between the discharge resistor and the resin mold.
Since the discharge resistor and the resin mold are not in direct contact with each other, the curing resistance shrinks when the mold resin is thermally cured, and the discharge resistance caused by the stress caused by the difference in the thermal expansion and contraction rate between the mold resin and the discharge resistor. It can prevent cracks on the surface of the device, significantly reduce the withstand voltage performance of the discharge resistor and significantly reduce the change in resistance value, and can also avoid physical stress such as thermal deformation during cooling and heating cycle tests. Long term quality stabilization of the heater is obtained, which contributes to the stabilization of the quality of dry capacitors with built-in discharge resistors, and is of great industrial and practical value.

[Brief description of the drawings]

FIG. 1 shows another embodiment of a dry capacitor with a built-in discharge resistor according to the present invention, in which (A) is an internal circuit configuration diagram and (B) is an enlarged view of a main part.

FIG. 2 shows a conventional dry-type capacitor with a built-in discharge resistor.
Is an internal circuit configuration diagram, and (B) is an enlarged view of a main part.

[Explanation of symbols]

 11: Dry capacitor with built-in discharge resistor 12: Capacitor element 13: Discharge resistor 14: Lead wire coated with silicon 15: Resin mold 16: Terminal for external drawing 17: Fluorine release agent 18: Gap 21: Dry type with built-in discharge resistor Capacitor 22: Capacitor element 23: Discharge resistor 24: Lead wire coated with silicon 25: Resin mold 26: Terminal for external drawing

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01G 4/40 H01G 4/224

Claims (1)

(57) [Claims] [Claim 1] to the one or a plurality of capacitor elements discharge resistor in parallel connection, interposed in a discharge resistor built dry capacitor formed by resin molding, a mold release agent between the discharge resistor and the molding resin Dry capacitor with built-in discharge resistor.