JP2562662Y2 - Feed-through filter - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a feedthrough type LC filter.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional through-type LC filter in which both ends of a cylindrical metal case 1 are formed to have a large diameter.
The multilayer capacitors 2 and 2 are housed in the large-diameter ends so as to abut against the inner diameter steps 3 and 3, and a through terminal 4 penetrating along the axis of the metal case 1 penetrates the multilayer capacitors 2 and 2. A ferrite bead 5 is externally fitted to a portion of the through terminal 4 between the capacitors 2 in the metal case 1.

[0003] The metal case 1 is generally formed of steel because of its strength, and the through terminal 4 is generally formed of copper in order to obtain a large current value when energized.
In the capacitors 2, the outer electrode 6 on the outer periphery is soldered to the metal case 1, and the inner electrode 7 on the inner periphery is soldered to the through terminal 4.

[0004]

When the capacitors 2 and 2 are soldered to the metal case 1 and the through terminal 4, a high temperature is applied to the metal case 1 and the through terminal 4; 1 and copper through terminal 4
Has a large difference in the thermal expansion coefficient. In particular, the expansion and contraction of the through terminal 4 is larger than that of the through terminal 4. Therefore, during the soldering operation of the capacitors 2 and 2, the through terminal 4 expands more than the metal case 1 and When the temperature returns to normal temperature, the metal case 1 contracts more greatly. Further, when used in a cryogenic environment, this difference is even greater.

As described above, the metal case 1 and the through terminal 4
When there is a difference in the amount of shrinkage, the through terminal 4 applies an inward force to the capacitors 2 and 2 fixed to the metal case 1, and this force is all supported by the soldered portion. Therefore, there is a problem that the inner electrodes 7 of the capacitors 2 and 2 are peeled off by this force, and a soldered portion between the capacitors 2 and 2 and the through terminal 4 is damaged.

In order to solve the above-mentioned problems, the present invention absorbs the difference in contraction between the metal case and the through terminal by the through terminal itself, and damages the soldered portion between the inner electrode of the capacitor and the through terminal. It is an object of the present invention to provide a through-type filter that can prevent occurrence of such a problem.

[0007]

In order to solve the above-mentioned problems, the present invention has a structure in which capacitors are housed at both ends in a metal case, and through terminals are provided along both the capacitors and the metal case along an axis. In the penetrating filter, the portion of the penetrating terminal located between the capacitors is formed in a bent shape.

[0008]

The bent shape formed in the portion of the through terminal located between the capacitors serves as a portion for absorbing the expansion and contraction of the through terminal, and mainly when the capacitor returns to room temperature after being soldered to the metal case and the through terminal. When used in a cryogenic environment, the difference in shrinkage of the through terminal with respect to the metal case is absorbed and mitigated by the bent shape, which prevents the inner electrode of the capacitor and the soldered portion of the through terminal from being subjected to force, and the inner electrode is Peeling and damage can be prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, a through filter has a large diameter inside both ends of a cylindrical metal case 11 made of steel, and a washer-type multilayer capacitor 1 is provided in both ends of the large diameter.
2 and 12 are stored so as to abut against the inner diameter steps 13 and 13,
A penetrating terminal 14 penetrating along the axis of the metal case 11 penetrates the multilayer capacitors 12, 12, and
A ferrite bead 15 is externally inserted into a portion of the through terminal 14 between the two capacitors 12 and 12, and the outer electrodes 16 of the two capacitors 12 and 12 are soldered to the metal case 11, and the inner electrode 17 to the through terminal 14. I have attached. The capacitors 12 and 12 are not limited to those having a laminated structure as shown in the figure, but may be any such as those having capacitor electrodes formed on both sides.

The through terminal 14 is made of copper in order to obtain a large current value when energized, and a portion located between the two capacitors 12 is bent at both ends and at the center thereof into a "<"-shaped bent shape 18. Is formed.

The ferrite bead 15 has a bifurcated structure on both sides because the bent portion 18 is formed between the two capacitors 12 of the through terminal 14. However, one or three or more ferrite beads 15 may be provided. .

The feed-through filter of the present invention has the above-described configuration, and the capacitors 12 and 12 are connected to the metal case 11.
When soldering with the through terminal 14, the metal case 11
Heat is transmitted to the penetrating terminals 14 and elongation occurs, but the elongation of the portion of the penetrating terminals 14 between the capacitors 12 can be absorbed by the bending of the bent shape 18.

When the temperature returns to normal temperature after soldering or when used in an extremely low temperature environment, both the metal case 11 and the through terminal 14 shrink. The bent portion 18 reduces the contraction, so that the inward force applied to the capacitors 12, 12 is reduced, and the inner electrode 1
7 can be reliably prevented from being peeled and the soldered portions of the capacitors 12, 12 and the through terminal 14 from being damaged.

The through-type filter may be repeatedly subjected to a thermal shock having a large temperature difference due to mounting on a circuit board. In this case as well, the difference in contraction between the metal case 11 and the through terminal 14 is reduced by the bent shape 18. As a result, it is possible to prevent the occurrence of breakage of the soldered portion between the capacitors 12 and the through terminal 14.

[0016]

As described above, according to the present invention, the portion of the capacitor and the through terminal penetrating through the metal case located between the two capacitors is formed in a bent shape, so that the metal case and the through terminal expand and contract due to heat. The difference in rate can be absorbed and mitigated by the bent part, and the force applied to the inner electrode part of the capacitor when the penetrating terminal expands and contracts after soldering of the penetrating terminal to the capacitor and the metal case is relaxed by the bent shape. This prevents the soldered portion between the capacitor and the through terminal from being damaged due to the peeling of the capacitor, thereby improving the reliability of the through filter.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a feed-through filter according to the present invention.

FIG. 2 is a longitudinal sectional view showing a conventional through-type filter.

[Explanation of symbols]

 Reference Signs List 11 metal case 12 capacitor 14 through terminal 16 outer electrode 17 inner electrode 18 bent shape

Claims (1)

(57) [Scope of request for utility model registration] In a through-type filter in which capacitors are housed at both ends in a metal case and a through terminal penetrates through both capacitors and the metal case along an axis, the capacitor is located between both capacitors of the through terminal. A through-type filter having a portion formed in a bent shape.