JPH0546022U - Terminal device for capacitors - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an excellent capacitor terminal device that can contribute to reduction in size and weight of a capacitor used for high voltage and large current, reduction in inductance, and improvement in reliability. [Structure] The electrode lead-out terminal 3 is arranged so as to penetrate the metal upper lid 2 of a metal case, and is fixed to the metal upper lid 2 by soldering 13. The electrode lead-out terminal 3 has an insulator 6 or a resin-molded insulator, and a central conductor 7 that serves as an electrode. An insulating layer 15 made of a curable insulating resin or a silicon compound is formed on the entire surface of the concave portion formed between the seamer convex portion 14 and the electrode lead terminal 3 on the surface of the metal upper lid 2. The insulating layer 15 completely covers at least the entire conductive portion including the soldering fixing portion 13 located around the electrode lead terminal 3.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a capacitor for industrial equipment, and more particularly, to a technique for improving a dielectric strength voltage between a metal upper lid and an electrode lead terminal in a capacitor having a metal case structure.

[0002]

[Prior Art]

 Among capacitors for industrial equipment, particularly, capacitors used in a GTO (gate turn off) snubber circuit have low inductance and high voltage and large current applications. Since these capacitors have low inductance, various innovations have been made in their internal structure and electrode lead terminal structure.

For example, as a case for accommodating a capacitor element, a case body made of metal is generally used because it absorbs expansion and contraction of insulating oil and is easy to process. A metal case with a metal top is used. In such a metal case, an electrode lead terminal is attached to the metal upper lid so as to penetrate the metal upper lid. In this case, the electrode lead-out terminal is formed by arranging a central conductor that serves as an electrode in an insulator or a resin-molded insulating material so as to penetrate therethrough, and constitutes a capacitor terminal device together with a metal top cover.

First, FIG. 3 is a diagram showing an example of a conventional capacitor using the metal case as described above. (A) is a plan view, (B) is a front view, and (C) is an internal view. It is a circuit diagram showing a connection. That is, as shown in FIG. 3, the metal case comprises a case body 1 made of metal and a metal top cover 2, and the metal top cover 2 is provided with electrode lead-out terminals 3 and earth terminals 4. Further, reference numeral 5 in the drawing denotes mounting feet, which are fixed by soldering to both ends of the bottom surface of the case body 1.

Next, FIG. 4 is a partial cross-sectional view showing the details of the electrode lead-out terminal 3 of the capacitor shown in FIG. 3, that is, the capacitor terminal device. That is, as shown in FIG. 4, the electrode lead-out terminal 3 has an insulator 6, a bolt terminal (center conductor) 7 penetratingly arranged in the insulator 6, and a nut 8 attached to the upper portion of the bolt terminal 7. ing. Then, the insulator 6 and the bolt terminal 7 are fixed by soldering between the upper and lower end surfaces of the insulator 6 and the corresponding portions of the bolt terminal 7, as shown by the soldering fixing portions 9 and 10. Has been done. A lead wire 11 drawn out from a capacitor element (not shown) housed in the case body 1 is connected to the lower end of the bolt terminal 7 and is fixed by a soldering fixing portion 10. Further, reference numeral 12 in the drawing denotes an insulating sleeve for the lead wire 11.

In FIG. 4, the electrode lead-out terminal 3 and the metal upper lid 2 are fixed to each other, as shown by a soldering fixing portion 13, on the outer peripheral surface of the flat portion 6 a for fixing the insulator 6 and the metal upper lid 2. This is done by soldering between the insulator 2 and the stepped portion 2a for mounting. The mounting portion of the case body 1 and the metal upper lid 2 is fixed by a seamer so as to have airtightness, as shown by a seamer convex portion 14.

[0007]

[Problems to be solved by the device]

 However, as described above, when the metal case is used as the case for accommodating the capacitor element, the following drawbacks occur.

That is, when the metal case is adopted, the terminal is provided on the metal upper lid as described above. However, in the case of high withstand voltage, it is necessary to secure a large creepage distance, so that the insulator becomes large. As a result, the metal case also becomes large. Then, as the size of the insulator and the metal case increases, the inductance increases. Further, as the inductance increases, the back electromotive force at the time of interruption becomes large, which may exceed the GTO standard. In this case, the maximum effective current cannot be used and the rating must be reduced.

As an example, a capacitor having 6 μF-4 kVDC, 9 kVAC between TC and an effective current Ie = 130 A was manufactured by a conventional technique. That is, first, two films each having a width of 50 mm and a thickness of 18 μm, one piece of a capacitor paper having a thickness of 14 μm, and an aluminum electrode foil were wound together to manufacture a 0.5 μF capacitor element. Eight of these capacitor elements were connected in parallel to form a capacitor element body having dimensions of 50 × 136 × 182 mm.

With respect to such a capacitor body, the body portion 6b of the insulator 6 of the electrode lead-out terminal 3 corresponding to the through portion of the bolt terminal 7 secures a sufficient creeping distance. Since it is necessary, a shape having a large fold with a high linear height of 22 mm and a creeping distance of 30 mm as shown in FIG. 4 was used. Further, the flat portion 6a provided on the insulator 6 was soldered and fixed on the step 2a provided on the metal upper lid 2.

In this case, the thickness of the flat portion 6a of the insulator 6 fixed onto the step 2a of the metal upper lid 2 becomes considerably thicker due to the relationship of increasing the fixing strength, and is lower than the level of the surface of the metal upper lid 2. It became a protruding shape.

As described above, since the insulator 6 has the large-diameter pleats, the length and width of the metal top cover 2 are considerably large due to the seaming work. That is, at the time of seaming work, since the metal upper lid 2 is pressed and fixed by the mold, a pressing margin of a certain size or more is required around the insulator 6 on the metal upper lid 2. Therefore, if the diameter of the insulator 6 is large as described above, the size of the metal cover 2 must be increased accordingly.

Subsequently, a case body 1 having the same size is prepared in accordance with the metal top cover 2 having such a large size, and the case body 1 and the metal top cover 2 are made airtight by a seamer. Fixed In this case, as shown in FIG. 3, the outer dimensions of the metal case were 240 × 75 × 180 mm, and the height of the electrode lead-out terminal 3 protruding from the metal case was 60 mm. Furthermore, since the outer dimensions of the metal case are increased in this way, the amount of insulating oil to be filled also increases, and the weight of the finished product with the insulating oil filled becomes as heavy as 5.4 kg. The size of the seamer convex portion 14 was 5 mm as shown in FIG.

In the capacitor configured as described above, the inductance is as high as 0.075 μH. When such a high-inductance capacitor is used in the GTO snubber circuit, the current can be reduced to a small current even though the GTO has a breaking capacity. In other words, depending on the inductance of the capacitor, there may be a case where a function that can be sufficiently realized by one GTO cannot be realized unless two GTOs are connected in parallel. As described above, using two G TOs complicates the circuit configuration and increases the size and weight of the device, which is not desirable.

On the other hand, as the size of the metal case increases and the amount of insulating oil filled in the case increases as described above, the amount of expansion and contraction of the insulating oil also increases. As a result, metal fatigue of the metal lid and May cause deformation. In other words, the insulating oil filled inside the case repeatedly expands and contracts due to changes in the ambient temperature.Therefore, when the amount of insulating oil increases, the metal top swells or dents as the insulating oil expands and contracts in large quantities. As a result, a large stress is applied to the soldering fixing portion 13 between the insulator 6 and the metal upper lid 2 shown in FIG. As a result, metal fatigue may occur in the same area, and cracks are likely to occur, which may lead to oil leakage. Further, due to the deformation of the metal top cover as described above, there is a possibility that the pitch dimension of the tip end portion of the electrode lead-out terminal may be expanded in a high temperature state and may not be within the specified dimension range.

The present invention has been proposed in order to solve the above-mentioned problems of the prior art, and its object is to provide a metal top cover and an electrode lead terminal in a capacitor using a metal case. Capacitors for high voltage and large current use can be made smaller, lighter, and lower in size by ensuring sufficient insulation between the center conductor and the size of the insulator or resin-molded insulation. An object of the present invention is to provide an excellent terminal device for a capacitor, which can contribute to an increase in inductance and reliability.

[0017]

[Means for Solving the Problems]

 In the capacitor terminal device according to the present invention, an electrode lead-out terminal is disposed so as to penetrate through the metal upper lid of a metal case in which a metal case body and a metal upper lid are fixed by a seamer so as to have airtightness. In the capacitor terminal device, which is fixed to the metal upper lid by attachment, the electrode lead-out terminal has an insulator or a resin-molded insulator, and a central conductor to serve as an electrode, the surface of the metal upper lid is accompanied by the seamer. The formed seamer protrusion, the recess formed between the seamer protrusion on the surface of the metal upper lid and the electrode lead terminal, and the curable insulating resin or silicon compound formed on the entire surface of the recess. And an insulating layer, and the insulating layer includes at least a soldering fixing portion located around the electrode lead terminal. It is characterized in that it is formed so as to cover the whole.

[0018]

[Action]

 In the capacitor terminal device of the present invention having the above-described configuration, by providing the curable insulating resin layer on the surface of the metal upper lid, the metal upper lid and the center conductor of the electrode lead-out terminal are It is possible to secure a sufficient creepage distance to withstand high voltage. Therefore, the insulator or the resin-molded insulator can be reduced in size, which can greatly contribute to the reduction in size and weight of the metal case and the reduction in inductance.

Further, since the curable insulating resin layer can improve the mechanical strength of the metal upper lid, the amount of deformation of the metal upper lid due to the expansion and contraction of the insulating oil can be significantly reduced, and the electrode extraction The stress applied to the soldered and fixed part between the terminal and the metal top cover can be significantly reduced. As a result, metal fatigue does not occur in the same part and cracks do not occur, so there is no risk of oil leakage. In addition, the change in the pitch dimension of the tip of the electrode lead-out terminal due to the deformation of the metal upper lid can be remarkably reduced, so there is no fear that it will fall outside the specified dimensions. Therefore, the reliability of the capacitor can be improved.

[0020]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. In this case, FIG. 1 is a partial cross-sectional view showing details of an embodiment of a capacitor terminal device according to the present invention, and FIG. 2 is a diagram showing an example of a capacitor using the capacitor terminal device of FIG. 3A is a plan view, FIG. 3B is a front view, and FIG. 3C is a circuit diagram showing the internal connection. The same parts as those of the prior art shown in FIGS. 3 and 4 are designated by the same reference numerals, and the description thereof will be omitted.

First, as an example according to the present invention, a capacitor having 6 μF-4 kVDC, 9 kVAC between T and C, and an effective current Ie = 130 A was manufactured as in the conventional example. Then, the same capacitor element was manufactured by using the same material as that of the conventional example, and the same capacitor element body was formed. That is, two 50 mm wide films each having a thickness of 18 μ, one piece of a capacitor paper having a thickness of 14 μ and an aluminum electrode foil were wound together to manufacture a capacitor element of 0.5 μF. Eight capacitor elements were prepared and connected in parallel to form a capacitor element body having a size of 50 × 136 × 182 mm.

Further, the shape of the insulator 6 of the electrode lead-out terminal 3 and the metal top cover 2 was formed as shown in FIG. That is, considering the creepage distance obtained by the insulating layer 15 provided on the surface of the metal top cover 2, the body portion 6b of the insulator 6 corresponding to the through portion of the bolt terminal 7 has a linear distance of 12 mm and a creepage distance of 12 mm. A small diameter straight shape with a low height. As a result, the height of the electrode lead-out terminal 3 was lowered to 40 mm.

In this case, the internal structure of the bolt terminal 7 and the insulator 6 fitted therein is a rotation stopping structure as shown in Japanese Patent Publication No. 1-100426. Further, by making the step size of the step part 2a of the metal upper lid 2 relatively large and making the thickness of the flat part 6a of the insulator 6 fixed to this substantially equal to the step size of the step part 2a, after soldering. The upper surface of the flat portion 6a was formed to be flush with the surface of the metal upper lid 2.

As described above, since the body portion 6b of the insulator 6 has a small diameter straight shape, the length and width of the metal top cover 2 can be reduced. Moreover, by arranging the upper surface of the flat portion 6a of the insulator 6 on the same plane as the surface of the metal upper lid 2, it becomes possible to use the flat portion 6a as it is as a press-fitting margin during seamer work. The length dimension and width dimension of the metal top cover 2 can be further reduced by that amount.

Then, a case body 1 having a small size is prepared in accordance with the metal top cover 2 having a small size to which the electrode lead-out terminal 3 is fixed as described above, and the case body 1 and the metal top cover 2 are It was fixed so that it had airtightness by soldering after seaming. In this case, as shown in FIG. 2, the outer dimensions of the metal case were as small as 200 × 65 × 180 mm, and the height of the electrode lead terminal 3 protruding from the metal case was 40 mm. At the same time, the internal wiring was able to be rational in proportion to the low inductance. Furthermore, since the metal case is downsized and the amount of filling insulating oil is small, the weight of the finished product filled with insulating oil is as light as 3.6 kg. The size of the seamer convex portion 14 was 5 mm as shown in FIG.

By the way, it is not possible to secure a sufficient creeping distance commensurate with the breakdown voltage by simply reducing the size of the metal case by using the electrode lead-out terminal 3 having the above-described shape. On the other hand, in this embodiment, according to the present invention, as shown in FIG. 1, the entire surface of the concave portion formed between the seamer convex portion 14 and the electrode lead-out terminal 3 of the metal upper lid 2, that is, the seamer convex portion 14 is formed. An insulating layer 15 made of a curable insulating resin or a silicon compound was formed on the entire surface of the metal upper lid 2 except for the portions where the portions 14 and the electrode lead-out terminals 3 were attached. In this case, the insulating layer 15 is formed thick so that the upper surface thereof is at the same level as the upper end of the seamer convex portion 14, and thus is formed so as to completely cover the solder fixing portion 13 of the electrode lead terminal 3. did. As a result of forming the insulating layer 15 in this way, a sufficient creeping distance commensurate with the breakdown voltage could be secured.

Therefore, in this embodiment, by providing the insulating layer 15 on the surface of the metal upper lid 2, the withstand voltage is improved, and in practical use, it is equal to or more than the case where the conventional capacitor terminal device is used. A capacitor having characteristics could be obtained. Moreover, the size of the metal case can be reduced, and as a result, the amount of insulating oil filled inside the case can be reduced, resulting in a significant weight reduction of the capacitor. At the same time, there is no longer any risk of inconvenience such as metal fatigue or case deformation associated with the expansion or contraction of insulating oil. Further, by ensuring the creepage distance by the insulating layer 15, the diameter and height of the electrode lead-out terminal 3 can be reduced, and the capacitor can be further downsized. Furthermore, due to the miniaturization of the metal case and the miniaturization of the electrode lead-out terminal 3 as described above, the inductance was as low as 0.06 μH.

In order to clearly show the function and effect of the present invention, the characteristics of the capacitor of the present embodiment (product of the present invention) and the capacitor of the conventional example (conventional product) described above are shown in Table 1 below.

[0029]

[Table 1]

As is clear from Table 1, in the product of the present invention, good results were obtained in terms of volume, weight, and inductance as compared with the conventional one. Further, when the capacitor body of the present invention product and the conventional product were installed at a high temperature of 80 ° C., the deformation amount of the metal upper lid in the present invention product was extremely smaller than the deformation amount of the metal upper lid in the conventional product. .. That is, the gap (displacement amount) in the pitch dimension of the tip of the electrode lead-out terminal is significantly less than 2 mm in the product of the present invention compared to 5 mm in the conventional product, and within the specified size range. A pitch dimension that was well within the limit was obtained.

Further, the operation effects of the present invention as described above are summarized as follows. (1) The size of the metal case can be reduced to about 72% of the conventional product, and the weight of the entire capacitor can be reduced to about 67% of the conventional product. (2) Since the inductance can be significantly reduced compared to the conventional product, the GTO cut-off current can be increased and the effective utilization rate can be improved. Moreover, the residual inductance can be reduced by about 15 to 20%. (3) Since the insulator of the electrode lead-out terminal can be downsized, the projecting dimension of the electrode lead-out terminal on the metal case can be shortened, and the overall size and weight of the capacitor can be reduced. (4) Since the size of the metal case is smaller, the amount of insulating oil filled inside the case can be reduced compared to conventional products, so that metal fatigue and deformation of the metal lid accompanying expansion and contraction of the insulating oil can be significantly reduced. It can be reduced. Therefore, there is no risk of oil leakage due to cracks caused by metal fatigue and dimensional problems due to changes in the pitch dimension of the electrode lead-out terminals caused by deformation, contributing to improved capacitor reliability. ..

It should be noted that the present invention is not limited to the above-described embodiment, and for example, the specific size and shape of the insulator can be changed as appropriate. Further, the rating and outer diameter of the capacitor to which the present invention is applied, the configuration of each part, and the like can be appropriately changed.

[0033]

[Effect of the device]

 As described above, in the present invention, by improving the simple structure in which the insulating layer made of the curable insulating resin or the silicon compound is provided on the surface of the metal upper lid, the metal upper lid and the center conductor of the electrode lead terminal are Insulation or resin-molded insulation can be downsized while ensuring sufficient insulation between them, thus making it possible to reduce the size and weight of capacitors that use high voltages and large currents, and reduce their inductance. It is possible to provide an excellent capacitor terminal device that can contribute to improving reliability.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing details of an embodiment of a capacitor terminal device according to the present invention.

2 is a diagram showing an example of a capacitor using the capacitor terminal device of FIG. 1, (A) is a plan view, FIG.
(B) is a front view, (C) is a circuit diagram showing internal connection.

FIG. 3 is a diagram showing an example of a conventional capacitor using a metal case, (A) is a plan view, (B) is a front view, and (C) is a circuit diagram showing internal connection.

4 is a partial cross-sectional view showing details of a capacitor terminal device of the capacitor of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Case body 2 ... Metal top lid 2a ... Step part 3 ... Electrode lead-out terminal 4 ... Ground terminal 5 ... Mounting foot 6 ... Insulator 6a ... Flat part 6b ... Body part 7 ... Bolt terminal (center conductor) 8 ... Nut 9, 10, 13 ... Soldering and fixing part 11 ... Lead wire 12 ... Insulation sleeve 14 ... Seamer protrusion 15 ... Insulation layer

Claims (1)

[Scope of utility model registration request] 1. An electrode lead terminal is arranged so as to penetrate through the metal upper lid of a metal case in which a metal case body and a metal upper lid are fixed by a seamer so as to have airtightness, and the metal lead body is soldered to the metal upper lid. Fixed to the metal lid,
In the capacitor terminal device, wherein the electrode lead-out terminal has an insulator or a resin-molded insulator, and a central conductor that serves as an electrode, on the surface of the metal upper lid, a seamer protrusion formed along with the seamer, On the surface of the metal upper lid, a concave portion formed between the seamer convex portion and the electrode lead terminal,
An entire conductive portion having an insulating layer made of a curable insulating resin or a silicon compound formed on the entire surface of the recess, and the insulating layer including at least a solder fixing portion located around the electrode lead terminal. A terminal device for a capacitor, which is formed so as to completely cover the.