JPH03218004A - Feed-through capacitor - Google Patents

Abstract

PURPOSE:To prevent connecting solder from re-melting at the time of mounting, by inserting a lead wire terminal composed of wire material of small thermal conductivity into the axial core part of a capacitor element, and soldering the lead wire terminal and a capacitor electrode. CONSTITUTION:Stainless wire, copper coated steel wire, etc., whose thermal conductivity is small are used as the wire material of a lead wire terminal 1. The lead wire 1 is inserted into a hole formed at the center of a capacitor element 5, and a stopper part 2 is fixed to a capacitor electrode 7a of the element 5 via solder 13a. Insulative resin 5 is poured into a metal case 10, and the space in the case 10 is filled with said resin. When this feed-through capacitor is mounted on a printed wiring board and the like, the soldering heat at the time of mounting is scarcely transmitted to the solder 13, because the thermal conductivity of the terminal 1 is small. As a result, the solder 13a can be prevented from re-melting.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a feedthrough capacitor used in constructing a single child circuit or the like.

Background of the Invention and Problems Conventionally, copper wires with excellent conductivity have been used for lead wire terminals, which are the center conductors of feedthrough capacitors. However, when using copper wire, if the soldering temperature is too high, the soldering time is too long, or the soldering heat source is too close when mounting the feedthrough capacitor to a printed wiring board, the lead wire terminals may The solder connecting the capacitor and one capacitor electrode of the capacitor element sometimes remelted. At this time, a problem occurred in that the remelted solder moved to another part and caused a short circuit with the other capacitor terminal. In addition, when Ag material is used as a capacitor electrode, remelted solder can cause "gun-pumping", resulting in a serious functional deterioration in which the capacitance value becomes lower than the designed value. was there.

One possible solution to the above problem is to use a solder material with a high melting point for the solder connecting the lead wire terminal and the capacitor electrode of the capacitor element. However, with this method, when connecting the lead wire and the capacitor element with high melting point solder, the entire component is exposed to high temperatures, which may cause the metal parts that make up the feedthrough capacitor to oxidize, resulting in poor appearance. There is. In order to prevent this oxidation, special soldering equipment will be required, and it can be expected that this will inevitably lead to an increase in cost.

Therefore, an object of the present invention is to prevent the solder connecting the lead wire terminal and the capacitor electrode of the capacitor element from remelting during mounting without requiring special equipment in the manufacturing process. The purpose of this invention is to provide a feedthrough capacitor that can

Means for Solving the Problems In order to solve the problems above, a feedthrough capacitor according to the present invention includes a lead wire terminal made of a wire material with low thermal conductivity and a capacitor element having a capacitive electrode, and the lead wire terminal is inserted into the shaft core of the capacitor element, and the lead wire terminal and one capacitance electrode of the capacitor element are connected via solder.

Since the lead wire terminal, which is the central conductor of action, is made of a wire material with low thermal conductivity, the heat generated when soldering the feedthrough capacitor to a printed wiring board, etc., is difficult to conduct through the lead wire terminal, and the contact between the lead wire terminal and the capacitor element is The solder connecting one capacitance-relaxing pole does not reach its melting point or becomes difficult to reach it.

Embodiment Hereinafter, one embodiment of a feedthrough capacitor according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a vertical cross-sectional view of a feedthrough capacitor.

This feedthrough capacitor has lead wire terminal 1 which is the center conductor.
, a capacitor element 5 through which this lead wire terminal 1 is inserted.
and a metal case 10.

Normally, the node line terminal 1 having a circular cross section can be used. At the center of the lead wire terminal 1, a stopper portion 2 for positioning and soldering the capacitor element 5 extends in a radial outward direction of the lead wire terminal 1. Lead wire terminal 1
As the wire rod, one having low thermal conductivity, such as stainless steel wire or CP wire (copper-coated steel wire), is used. The thermal conductivity of stainless steel wire is 25.4 W/m-K, which is extremely low compared to the thermal conductivity of copper wire, which is approximately 400 W/m-K. The capacitor element 5 includes a donut-shaped dielectric body 6 having a hole 8 in the center, and capacitive electrodes 7a provided on the front and back surfaces of the donut-shaped dielectric body 6. 7b.

The metal case 10 has a substantially cylindrical shape and includes a large diameter portion 11 and a small diameter portion 12. Usually metal case 10
is used as a ground terminal.

The capacitor element 5 is housed from the open end side of the large diameter section 11 of the metal case 10, and its capacitance 1 pole 7b is attached to the inner wall of the transition wall portion 11a forming a part of the large diameter section 11 via solder 13b. It is fixed in an electrically connected state. Then, the lead wire terminal 1 was inserted into the hole 8 provided in the center of the capacitor element 5, and the stopper part 2 was attached to the capacitance T pole 7a of the capacitor element 5 and was electrically connected via the solder 13a. Fixed state. Insulating resin is poured into the thus assembled structure through the large diameter part 11 opening and the small diameter part 12 opening of the metal case 10, and the metal case 10 is made of metal so that both ends of the lead wire terminal 1 are exposed from the insulating tree 15. The space inside the case 10 is filled with an insulating resin 15. When the obtained feedthrough capacitor is mounted on a printed wiring board, etc., because the thermal conductivity of the lead wire terminal 1, which is the center conductor, is low, the soldering temperature during mounting may be too high or the soldering time may be too long. Even if the heat is
As a result, the mounting solder 13 connecting the lead wire terminal 1 and the capacitive electrode 7a of the capacitor element 5
a does not reach the melting point or becomes difficult to reach. Therefore,
The mounting solder 13a does not re-melt or becomes difficult to re-melt.

Note that the feedthrough capacitor according to the present invention is not limited to the above-mentioned embodiments, and can be modified in various ways within the scope of the invention. Furthermore, the present invention can also be applied to devices in which the capacitor element is not mounted in a metal case.

Effects of the Invention As is clear from the above explanation, according to the present invention, since the lead wire terminal, which is the center conductor, is made of a wire material with low thermal conductivity, the heat generated when soldering the feedthrough capacitor to a printed wiring board, etc. Therefore, a feedthrough capacitor is obtained in which the solder connecting the lead wire terminal and the capacitance electrode of the capacitor element is less likely to be remelted. As a result, it is possible to reduce problems such as ``crossing of the furnace poles'' and short circuits between the capacitor electrodes.

Further, the manufacturing process of the feedthrough capacitor does not require any special equipment, and conventional equipment can be used as is, resulting in an inexpensive feedthrough capacitor.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a feedthrough capacitor according to the present invention. 1... Lead wire terminal, 5... Capacitor element, 7a
...Capacity T pole, 13a...Mounting solder.

Claims (1)

[Claims] 1. A lead wire terminal made of a wire with low thermal conductivity and a capacitor element having a capacitor electrode are provided, the lead wire terminal is inserted into the shaft core of the capacitor element, and the lead wire terminal and one capacitor electrode of the capacitor element are connected to each other. A feed-through capacitor characterized by: connected through solder.