JPH0982566A - Feed-through capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a feed-through capacitor where a higher insertion loss can be obtained, in a frequency range required in limited electrostatic capacitance. SOLUTION: A capacitor element is constituted by forming a laminate by stacking metallic foils 1 and 2 consisting of inner electrodes 1a and 2a and a plurality of leads (tabs 1b and 2b) provided around the periphery and dielectrics 3 in multilayer, and forming a hole for passage of a terminal in a vertical direction to the face of the inner electrode parts at the center of the laminate, and the lead part is bent to one side face of the capacitor element so that it may be parallel with the inner electrode parts 1a and 2a, and it is attached to a metallic case 10 through an insulator sleeve 6 by the terminal 7 piercing the hole for passage of a terminal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency noise used between a terminal and a case, which is commonly referred to as Y-con, in a noise filter for preventing high-frequency noise flowing out and flowing in through a power line in a device which receives power from a distribution system. The present invention relates to a feedthrough capacitor for removing noise.

[0002]

2. Description of the Related Art FIG. 10 is a diagram showing the structure of a conventional feedthrough capacitor of this type. As shown in the figure, a conventional feedthrough capacitor is a film or paper (hereinafter referred to as "dielectric 23") and two metal foils (not shown) are stacked so that the metal foils are exposed at different end faces, and this is formed into a cylindrical shape. Of the insulating material 24 or the dielectric material 23 on which metal is vapor-deposited is shifted in the width direction and overlapped with each other, and the end surface of the cylindrical insulating material 24 is sprayed with metal powder to form a cylindrical insulating material. A terminal 2 (not shown) is passed through the center hole of the body 24, and is further wound.
3, a case side electrode 22 is provided at one end and a terminal side electrode 21 is provided at the other end, the terminal side electrode 21 is electrically connected to the terminal passing through the center hole of the insulator 24, and the case side electrode 22 is electrically connected to a metal case. Connected to each other.

[0003]

In the conventional feedthrough capacitor having the above structure, the impedance of the capacitor element is minimized in order to remove high frequency noise.
Therefore, since this feedthrough capacitor functions as an ideal capacitor, the high frequency noise removing effect (hereinafter, referred to as “insertion loss α”) depends on the frequency f and the capacitance C.
It is uniquely determined by "α∝1 / fC". Therefore, in order to obtain the required insertion loss at a specific frequency, the capacitance C of the capacitor element must be increased.

However, on the other hand, the leakage current i _LC of the noise filter for the power source is 1 because of the safety problem to the human body.
Since there is a demand of mA or less or several mA or less and the leakage current i _LC is determined by “i _LC = n × 2πfCV” (n is the number of capacitors), the capacitance of the feedthrough capacitor is limited. However, there is a problem that a higher insertion loss α cannot be obtained.

The present invention has been made in view of the above points, and an object of the present invention is to provide a feedthrough capacitor which can obtain a higher insertion loss α in a frequency range required with a limited capacitance. .

[0006]

In order to solve the above problems, the invention according to claim 1 is a metal foil comprising an internal electrode portion and a plurality of lead portions provided on the outer periphery of the internal electrode portion,
The dielectrics are laminated in multiple layers to form a laminated body, and a terminal penetrating hole is formed in the central portion of the laminated body in a direction perpendicular to the surface of the internal electrode portion to form a capacitor element, and a lead-out portion is formed. It is characterized in that it is configured to be bent to one side surface of the capacitor element so as to be in equilibrium with the internal electrode portion, and to be attached to a metal case with an insulator interposed by a terminal penetrating the terminal penetrating hole. .

According to a second aspect of the present invention, in the feedthrough capacitor according to the first aspect, the capacitor element has a regular polygonal shape or a circular shape, and a central portion thereof is perpendicular to a surface of the internal electrode. It is characterized in that a hole for penetrating the terminal is formed.

Further, the invention according to claim 3 is the feedthrough capacitor according to claim 1 or 2, wherein insulating plates are attached to both end faces of the capacitor element, and the lead-out portion of the metal foil is attached to the insulating plate. It is characterized by being bent outward through the outer circumference.

According to a fourth aspect of the present invention, in the feedthrough capacitor according to the third aspect, the peripheral portion of the lead-out portion of the insulator plate on the case side is larger than the capacitor element.

Further, an insulator plate is added between the insulator plate on the case side and the case, and the peripheral portion of the drawer portion is larger than the insulator plate.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing an example of a feedthrough capacitor of the present invention, FIG. 1 is a side sectional view, and FIG. 2 is a front view. In FIG. 1, the feedthrough capacitor is enlarged in the stacking direction for easy understanding of the structure. In the figure, 1 is an electrode having an internal electrode portion 1a and a lead-out portion (hereinafter referred to as "tab") 1b from the internal electrode portion 1a, and 2 is an internal electrode portion 2a and the internal electrode portion 2a. Is an electrode having a lead-out portion (hereinafter, referred to as “tab”) 2b. The electrodes 1 and 2 are metal foils of aluminum or copper having a thickness of about 15 μm.

Reference numeral 3 denotes a dielectric made of a resin film such as PP, PET, PPS or a capacitor paper, which is inserted between the internal electrode portion 1a and the internal electrode portion 2a, and between the internal electrode portions 1a and 2a. It has a role as an electrical insulator and a dielectric. A capacitor element is formed by the electrode 1, the electrode 2 and the dielectric 3. The internal electrode portions 1a, 2a and the dielectric 3 are formed in a regular hexagonal shape.

4 and 5 have a bending strength of a certain level or more 6
This is a rectangular insulator plate, and the capacitor element composed of the electrode 1, the electrode 2, and the dielectric 3 is sandwiched between the insulator plate 4 and the insulator plate 5 and held. Terminal side tab 1 of electrode 1
b is bent on the outer circumference of the insulator plate 4, and the case-side tab 2b of the electrode 2 is bent on the outer circumference of the insulator plate 5.

Reference numeral 6 denotes an insulator cylinder having a bending strength of a certain level or more, and the insulator cylinder 6 serves to electrically insulate the terminal 7 from the capacitor element. Further, although the insulator cylinder 6 is formed integrally with the insulator plate 4 in the drawing, it may be formed separately.

A metal plate (or foil) 8 electrically connects the terminal-side tab 1b of the electrode 1 to the terminal 7. Reference numeral 9 denotes an insulator plate, which is interposed between the metal case 10 and the insulator plate 9 to secure a distance between the terminal-side tab 1b of the electrode 1 and the edge surface of the case 10.

In the case of the feedthrough capacitor having the above-mentioned structure, the terminal 7 is passed through the terminal through hole at the center of the insulator cylinder 6, and both ends of the feedthrough capacitor are tightened with nuts 11 and 12.
Fixed to. In addition, 13 and 14 are an insulator cylinder and a washer which are interposed between the nut 12 and the case 10, respectively. As a result, the feedthrough capacitor is inserted between the metal plate 8 electrically connected to the terminal 7 and the case 10.

In a conventional feedthrough capacitor, as shown in FIG. 10, a high frequency noise current flows in from one terminal and flows out from the other terminal, so that an inductance exists inside the capacitor element, but as shown in FIGS. 1 and 2. With this configuration, many tabs 1b and 2b have multiple terminals, and the inductance inside the capacitor element is further reduced.

Further, the feedthrough capacitor having the above structure utilizes resonance due to the inductance of the tabs 1b and 2b and the internal capacitance of the capacitor element in order to obtain higher insertion loss in the required frequency range. Further, in order to maintain the high insertion loss characteristic even at a frequency higher than the resonance frequency, a capacitance is provided between the tabs 1b and 2b and the internal electrodes 1a and 2a, so that the tab 1 at a frequency higher than the resonance frequency is provided.
The inductances of b and 2b are reduced.

Further, since the feedthrough capacitor has a terminal feedthrough structure, it is possible to obtain an effective insertion loss in a frequency range higher than that of the discrete capacitor as will be described later.

FIG. 3 is a front view showing an example of the feedthrough capacitor of the present invention. In the figure, the parts designated by the same reference numerals as those in FIG. 1 and FIG. As shown in the figure, in the feedthrough capacitor, the internal electrode portions 1a and 2a and the dielectric 3 are circular.

4 and 5 are views showing an example of the feedthrough capacitor of the present invention. FIG. 4 is a front view and FIG. 5 is an exploded perspective view. In the figure, the parts designated by the same reference numerals as those in FIG. 1 and FIG. This feedthrough capacitor has a terminal side tab 1b.
And three tabs 2b on the case side, and the tabs 1b, 2
The shape of b is a triangle.

FIG. 6 is a diagram showing an equivalent circuit of the feedthrough capacitor having the above structure. In the capacitor element, the terminal-side internal electrode portion 1a and the case-side internal electrode portion 2a are opposed to each other with the dielectric 3 interposed therebetween, and form a capacitance C. Further, the tabs 1b and 2b drawn out from the outer peripheral portion of the capacitor element have inductances Lt and Lt and the internal electrode portion 1 is provided.
Since it is parallel to a and 2a, it has a capacitor Ct between the internal electrode portions 1a and 2a.

Therefore, the feedthrough capacitor has tabs 1b and 2b.
Of the inductances Lt, Lt, the internal electrode portions 1a, 2a, and the electrostatic capacitance C of the laminated body of the dielectric 3, and the series resonance frequency F0, , Or the inductances Lt and Lt of the tabs 1b and 2b, the tabs 1b and 2b, and the internal electrode portion 1a,
Parallel resonance frequency F due to capacitances Ct and Ct between 2a
0 ', Due to the parallel resonance, the insertion loss can be maintained even in a frequency range higher than the series resonance frequency. The relationship between this frequency and insertion loss is shown in FIG.

Further, the shape of the capacitor element is a circle or a regular polygon, and the through hole for the terminal 7 is provided at the center thereof, so that the electromagnetic fields due to the high frequency noise currents flowing inside the capacitor element cancel each other out. Therefore, the internal impedance of the capacitor element can be suppressed low, and the insertion loss characteristic can be further improved.

FIG. 8 is a diagram showing insertion loss characteristics of the conventional feedthrough capacitor and the feedthrough capacitor of the present invention (the feedthrough capacitor shown in FIGS. 1 and 2). In the figure, curve A shows the feedthrough capacitor of the present invention, and curve B shows the conventional feedthrough capacitor. As shown in the figure, in the frequency range of 20 MHz to 400 MHz centered on the series resonance frequency F0,
The insertion loss is improved over the conventional one. Further, at the parallel resonance frequency F0 ′ or higher, the resonance effect of the electrostatic capacitances Ct and Ct between the inductances Lt and Lt of the tabs 1b and 2b and the internal electrode portions 1a and 2a appears, and 400M
The insertion loss of about 50 dB is maintained at Hz to 800 MHz.

FIG. 9 is a diagram showing insertion loss characteristics when the number of tabs is changed in the feedthrough capacitor according to the present invention. Each of A, B and C shows the feedthrough capacitor of the present invention, A shows the case of two tabs, B shows the case of three tabs, and C shows the case of six tabs. D is a conventional feedthrough capacitor, and E is a discrete capacitor. As shown in the figure, according to the feedthrough capacitors A, B, and C of the present invention, the series resonance frequency F0 can be changed by changing the number of tabs, and the conventional feedthrough capacitor D and the discrete capacitor E can be obtained. It is possible to obtain an insertion loss characteristic that has not been obtained.

[0027]

As described above, according to the present invention, a metal foil having a plurality of drawn portions on the outer periphery of the internal electrode portion and a dielectric are laminated in multiple layers to form a laminated body, and a central portion is formed in the central portion. A capacitor element is formed by forming a hole for terminal penetration perpendicular to the surface of the internal electrode section, and the lead-out section is bent to one side of the capacitor element so that it is parallel to the internal electrode section to form a feedthrough capacitor. Therefore, an excellent effect that a feedthrough capacitor that can obtain a higher insertion loss α can be provided in the frequency range required with a limited electrostatic capacitance is obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an example of a feedthrough capacitor of the present invention.

FIG. 2 is a front view showing an example of a feedthrough capacitor of the present invention.

FIG. 3 is a front view showing an example of a feedthrough capacitor of the present invention.

FIG. 4 is a front view showing an example of a feedthrough capacitor of the present invention.

FIG. 5 is an exploded perspective view showing an example of a feedthrough capacitor of the present invention.

FIG. 6 is a diagram showing an equivalent circuit of the feedthrough capacitor of the present invention.

FIG. 7 is a diagram showing the relationship between the frequency and the insertion loss of the feedthrough capacitor of the present invention.

FIG. 8 is a diagram showing a comparative example of insertion loss characteristics of the feedthrough capacitor of the present invention and a conventional feedthrough capacitor.

FIG. 9 is a diagram showing a comparative example of insertion loss characteristics of the feedthrough capacitor of the present invention and conventional feedthrough capacitors and discrete capacitors.

FIG. 10 is a diagram showing a conventional feedthrough capacitor.

[Explanation of symbols]

 1 Electrode 1a Internal electrode part 2 Electrode 2a Internal electrode part 3 Dielectric 4 Insulator plate 5 Insulator plate 6 Insulator cylinder 7 Terminal 8 Metal plate 9 Insulator plate 10 Case 11 Nut 12 Nut 13 Insulator cylinder 14 Washer

Claims (5)

[Claims] 1. A metal foil comprising an internal electrode portion and a plurality of lead-out portions provided on the outer periphery of the internal electrode portion, and a dielectric are laminated in multiple layers to form a laminated body, and a central portion of the laminated body. To form a terminal penetrating hole in a direction perpendicular to the surface of the internal electrode portion to form a capacitor element, and bend the lead portion to one side surface of the capacitor element so as to be parallel to the internal electrode surface, A feedthrough capacitor characterized in that it can be attached to a metal case with an insulator interposed by a terminal penetrating the terminal penetration hole. 2. The feedthrough capacitor according to claim 1, wherein the capacitor element has a regular polygonal shape or a circular shape,
The through-hole capacitor is characterized in that a hole for penetrating the terminal is formed in a central portion thereof in a direction perpendicular to a surface of the internal electrode. 3. The feedthrough capacitor according to claim 1 or 2, wherein an insulator plate is attached to both end faces of the capacitor element, and a lead-out portion of the metal foil passes through an outer periphery of the insulator plate to an outside. A feedthrough capacitor characterized by being bent into 4. The feedthrough capacitor according to claim 3, wherein a peripheral portion of the lead-out portion of the insulator plate on the case side is larger than the capacitor element. 5. A feedthrough capacitor, characterized in that an insulator plate whose peripheral portion around the lead-out portion is larger than the insulator plate is added between the insulator plate on the case side and the case.