JP6933756B2 - Metallized film capacitor - Google Patents

Description

According to the present invention, a metallized film capacitor in which the main body of a wound type capacitor element is housed in an outer case and then sealed with a resin. A mold capacitor element, a resin outer case that houses the main body of the capacitor element except for a part of the lead-out electrode, and a seal that is filled in the outer case and solidifies to cover the main body of the capacitor element. The present invention relates to a metallized film capacitor equipped with a resin.

For example, a capacitor element for an inverter device (DC-AC conversion device) is a metal thin film electrode having a different electrode that sandwiches a dielectric film due to the application of a voltage at a high frequency between a pair of lead-out electrodes at both ends in the axial direction. A Coulomb force acts between them, causing mechanical vibration. In recent years, as the switching frequency of an inverter device has increased, the frequency of mechanical vibration has also increased, and an unpleasant noise (for example, an unpleasant roaring sound of "keen") has become a problem.

Metallized film capacitors include winding type (cylindrical type, flat columnar type), laminated type, etc. as their capacitor elements, but in the case of winding type, the winding tension (winding tension) when winding the metallized film. Conventionally, noise is suppressed by increasing the tension) to perform strong winding and narrowing the film layers.

In addition, as a measure to reduce vibration (noise), recesses (groove-shaped recesses extending in the axial direction to the opening end of the case, holes scattered at approximately equal intervals in the circumferential direction and the axial direction) are formed on the inner wall of the resin outer case. A metallized film capacitor has been proposed in which a concave portion, a groove-shaped concave portion extending spirally from the bottom surface to the opening end) is formed, and the concave portion is also filled with a sealing resin (see, for example, Patent Document 1).

In the case of this conventional example, when the sealing resin that encloses the capacitor element absorbs the vibration, the vibration is absorbed by filling the inside of the recess formed in the inner wall of the outer case with the sealing resin biting into the inside. It is said that the capacitor element is firmly fixed via the sealing resin to effectively absorb vibration. This method follows the idea of absorbing vibration at its location.

Conventionally, a double-wall sound insulation type electric appliance container different from the method of Patent Document 1 described above has been proposed. The container side plate portion has a double wall structure, and the space inside the double wall is a filling layer such as an air layer, a vacuum layer, or glass fiber. However, the electrical equipment container is made of metal, and both the inner plate and the outer plate constituting the double wall are metal plates, which are fixed to the bottom plate, which is also a metal plate, by welding. The metal electric device container including the double wall accommodates the electric device such as a capacitor and the insulating oil covering the electric device in its internal space (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2009-94266 Jikkai Sho 63-67218

The present invention is a metallized film capacitor in which the main body of a wound capacitor element is housed in an outer case and then sealed with a resin. An object of the present invention is to effectively reduce noise such as sound, but the techniques described in the above two patent documents have not been sufficient to solve this problem.

The metallized film capacitors shown in FIGS. 17 and 18 (a), (b), and (c) have the same basic configuration as the present invention, and as described at the beginning, the capacitor element 1 This is a conventional example of a type including a resin outer case 3 for accommodating the main body 1a and a sealing resin 4 which is filled in the outer case 3 and covers the main body 1a of the capacitor element by solidification. The outer case 3 has a box shape with an upper opening, and a pair of side plate portions 3a ′ and 3a ′ facing each other in the Z direction corresponding to the axial direction of the capacitor element 1 and a pair of front plate portions 3b and 3b facing each other in the Y direction. And the bottom plate portion 3c at the lower end in the X direction, and the whole is integrally molded with synthetic resin. Reference numeral 2 is a lead-out electrode, and 3d is a storage space.

In the case of a wound metallized film capacitor, the vibration energy is concentrated in the axial center (center), and the vibration propagates from there to both outer sides in the axial direction, and finally both sides in the axial direction. It tends to be accompanied by the phenomenon of coming out of. With the recent increase in the frequency of inverter devices, this tendency is becoming stronger.

In the case of the conventional example of FIGS. 17 and 18, the high-frequency sound wave bundle vertically incident on the side plate along the axial direction escapes toward the outside of the side plate portion 3a'of the single piece. At this time, it spreads and propagates at a certain solid angle through the vibration of one side plate portion 3a'. However, its solid angle is limited to a relatively small one with a thin conical cylinder such as a megaphone, and the diffusion region is only in one direction. That is, it is only a single relatively narrow solid angle region around the extension in the axial direction. This is probably because of this, but the noise such as howling noise in the axial direction (Z direction) of the capacitor element is considerably large.

The present inventor has conducted a measurement test of noise such as a growl in the axial direction of the capacitor element and two directions orthogonal to the axial direction of the wound type metallized film capacitor. The axial direction of the capacitor element is the Z direction, and the directions along the opening direction (upward direction) of the resin outer case accommodating the capacitor element in two directions orthogonal to the Z direction are the X direction, the Z direction and the X direction. The direction orthogonal to each other is the Y direction.

As a measurement test, the measurement was performed by changing the type of sealing resin to be injected and filled in the outer case. As a result, it has become clear that there are types of sealing resins that are effective in reducing noise such as growls, but it has been found that they do not reach a level that can sufficiently meet the demands of recent users. ..

Specifically, it has become clear that the effect of reducing noise such as growls has a direction. That is, although a corresponding noise reduction effect was observed in the X direction and the Y direction, a satisfactory noise reduction effect was not observed in the Z direction. The following phenomena can be considered as the cause.

As described above, in the winding type capacitor element, the vibration energy concentrated from the peripheral part to the axial center portion propagates toward both outer sides in the axial direction at the axial center portion and escapes to the outside. Along with this, the strength of pulling out in the axial direction is increasing. As a result, the noise reduction effect was not satisfactory in the Z direction even if various measures were taken as described above.

The present invention has been created in view of such circumstances. Regarding a metallized film capacitor in which the main body of a wound capacitor element is housed in an outer case and then sealed with a resin, particularly in the axial direction of the capacitor element. The purpose is to improve the effect of reducing noise such as howling noise in the (Z direction).

The present invention solves the above problems by taking the following measures.

The metallized film capacitor according to the present invention
A metallized film-wound capacitor element with lead-out electrodes connected to both ends in the axial direction,
A resin outer case that houses the main body of the capacitor element except for a part of the lead-out electrode, and
A metallized film capacitor provided with a sealing resin that is filled in the outer case and covers the main body of the capacitor element by solidification.
The side plates at both ends in the axial direction of the outer case are formed as a double wall of an outer plate and an inner plate facing each other in the axial direction, and are perpendicular to the axial direction between the outer plate and the inner plate. A gap for diffusion of sound wave bundles is formed, which develops in various directions .
The outer case is characterized in that the entire outer case including the inner plate and the outer plate is integrally molded by injection molding of resin .

The above configuration according to the present invention exerts the following effects.

By forming the side plates at both ends of the outer case into a double wall consisting of an outer plate and an inner plate facing each other in the axial direction, noise such as a growl is diffused between the outer plate and the inner plate. It forms a gap for diffusing the sound wave bundle, which has a function of reducing the sound wave bundle. It does not directly target the generation of noise for suppression, but reduces the generated noise by diffusing it after it is generated.

The space for diffusing the sound wave bundle is a space sandwiched between a double wall of an outer plate located on the outermost side in the axial direction and an inner plate facing the inner side in the axial direction. Each of the side plate portions at both ends in the axial direction of the outer case in which the gap portion is formed corresponds to the outer plate and the inner plate constituting the double wall.

The gap for diffusing the sound wave bundle is formed by being sandwiched by a double wall of an inner plate and an outer plate facing the inner plate. Therefore, the vibration energy of the high-frequency sound wave bundle propagating from the axial center portion of the capacitor element to both outer sides along the axial direction can be introduced from the inner plate into the gap portion for diffusion of the sound wave bundle. The high-frequency sound wave bundle that has passed through the inner plate is diffused in the propagation direction in the gap after passing. The direction of diffusion of the high-frequency sound wave bundle is a direction perpendicular to the axial direction (element axial direction), which is the direction in which the gap is developed, and a synthesis direction at various inclination angles between the vertical direction and the axial direction. .. The entire region that aggregates the various directions is a solid angle region that extends 360 degrees around the axis of the capacitor element. Regarding this itself, it does not matter whether or not there is an opening that communicates with the outside in the propagation direction. Immediately after passing through the inner plate, the high-frequency sound wave bundle diffuses in the gap portion for diffusing the sound wave bundle in a solid angle region having a spread of 360 degrees around.

In the diffusion of 360 degrees around the axis of the capacitor element, if there is an opening that communicates and opens to the outside, the escape of the high-frequency sound wave bundle along the direction is promoted. If there is no opening that communicates with the outside and opens to the outside, it is a connecting beam that connects (continuously) the inner plate and the outer plate along the axial direction, but the high-frequency sound wave bundle is the connecting beam. It diffuses into the external space through the vibration of the part. In any case, the diffusion solid angle region of the high-frequency sound wave bundle in the direction perpendicular to the axial direction after coming out of the inner plate (one side plate in the conventional example) is sufficient in the present invention as compared with the conventional example. It has become a big one.

As described above, in the present invention, the metallized film-wound capacitor element housed in the outer case of the upper opening in a horizontal position is covered with a sealing resin, and the capacitor element is axially oriented from the axial center portion. The high-frequency sound wave bundle propagating along the line is sandwiched between the double walls of the inner plate of the outer case and the outer plate facing the outer plate, and is formed by sandwiching the sound wave bundle in the direction perpendicular to the axial direction due to the presence of a gap for sound wave diffusion. Since it is diffused over a wide area, it is possible to improve the effect of reducing noise such as a roaring sound in the axial direction (Z direction).

The metallized film capacitor of the present invention having the above configuration has several preferable modes or changes / deformation modes as follows.

[1] The gap portion for diffusing the sound wave bundle is in a positional relationship that intersects with the extension line of the axial center of the capacitor element. In this case, it is possible to efficiently introduce the vibration energy of the high-frequency sound wave bundle propagating from the axial center portion of the capacitor element to both outer sides along the axial direction into the gap portion for diffusing the sound wave bundle.

[2] The central portion of the gap portion for diffusing the sound wave bundle is located near the extension line of the axial center of the condenser element. In this case, the high-frequency sound wave bundle entering the gap for diffusing the sound wave bundle can be diffused substantially evenly in all directions in the 360-degree range around the axial center.

[ 3 ] The capacitor element has a cylindrical shape in which the axial core portion is hollow, and the cavity in the axial core portion is also filled with the sealing resin.

According to the present invention, since the gaps for diffusion of sound wave bundles formed by being sandwiched between the inner plate and the outer plate facing each other are arranged on both outer sides in the axial direction of the winding type condenser element, the condenser element The vibration energy of the high-frequency sound wave bundle propagating from the axial center portion to both outer sides along the axial direction can be introduced from the inner plate to the gap portion. The gap portion for diffusing the sound wave bundle develops in a direction perpendicular to the axial direction, and the vibration energy entering the gap portion through the inner plate diffuses in the gap portion in the radial direction from the axial center portion. As a result, the high-frequency sound wave bundle propagating from the capacitor element along the axial direction can be diffused over a wide range in the gap for diffusing the sound wave bundle, and the effect of reducing noise such as roaring sound in the axial direction is particularly excellent. can do.

Perspective view showing a metallized film capacitor in the first embodiment of the present invention. Top view, front view and side view of the metallized film capacitor in the first embodiment. Perspective view and vertical sectional view of the main part of the metallized film capacitor in the first embodiment. Perspective view showing a metallized film capacitor in the second embodiment of the present invention. Top view, front view and side view of the metallized film capacitor in the second embodiment. Perspective view and vertical sectional view of the main part of the metallized film capacitor in the second embodiment. Perspective view showing a metallized film capacitor in the third embodiment of the present invention. Top view, front view and side view of the metallized film capacitor in the third embodiment. Perspective view and vertical sectional view of the main part of the metallized film capacitor in the third embodiment. Perspective view showing the metallized film capacitor in the 4th Example of this invention. Top view, front view and side view of the metallized film capacitor in the fourth embodiment. Perspective view and vertical sectional view of the main part of the metallized film capacitor in the fourth embodiment. A perspective view showing a metallized film capacitor according to a fifth embodiment of the present invention. Top view, front view and side view of the metallized film capacitor in the fifth embodiment. Perspective view and vertical sectional view of the main part of the metallized film capacitor in the sixth embodiment. Noise intensity-frequency characteristic diagram obtained as a result of noise measurement tests such as growls performed for the five examples and the conventional example. A perspective view showing the configuration of a conventional metallized film capacitor. Top view, front view and side view of the conventional metallized film capacitor

Hereinafter, embodiments of the metallized film capacitor of the present invention having the above configuration will be described in detail at the level of specific examples.

[First Example]
A first embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3. FIG. 1 is a perspective view showing a metallized film capacitor according to the first embodiment of the present invention, FIGS. 2 (a), 2 (b) and 2 (c) are a plan view, a front view and a side view thereof, and FIG. 3 (a). , (B) is a perspective view of the main part, and FIG. 3 (c) is a vertical sectional view of the main part.

In these figures, 1 is a metallized film winding type capacitor element, 1a is a main body of the capacitor element 1, 2 is a lead-out electrode, 3 is a resin outer case, and 4 is a sealing resin. 3a is a side plate portion at both ends in the axial direction in the outer case 3, 3b is a front plate portion in the outer case 3, 3c is a bottom plate portion in the outer case 3, 5 is a gap portion for sonic bundle diffusion formed in the side plate portion, 3a ₁ Is the inner plate in the side plate portion 3a, and 3a ₂ is the outer plate in the side plate portion 3a.

FIG. 3 shows an enlarged view of one side plate portion 3a and its peripheral portion, and FIG. 3A shows a portion of the outer case 3 with a solid line and a portion of the gap portion 5 for sound wave bundle diffusion with a broken line. 3 (b) shows the gap portion 5 with a solid line, the outer case 3 portion with a broken line, and FIG. 3 (c) shows a cross-sectional view of the gap portion 5 longitudinally crossed in the XY two-dimensional direction.

As shown in FIG. 1, the capacitor element 1 is formed by spraying metal onto the main body 1a of the capacitor element formed by repeatedly winding a metallized film to form a cylindrical shape and both ends of the main body 1a in the axial direction. It has a pair of lead-out electrodes 2 and 2 of a positive electrode and a negative electrode soldered to a metal spray electrode (metallic capacitor).

Here, the metallized film is formed by forming a metal thin film electrode on one side of a dielectric film by vapor deposition or the like, and the two metallized films are wound in a state of being overlapped with each other. At the time of winding, a thin-walled cylindrical winding core produced by multiple winding of the pre-winding film is used as a core material, and two metallized films in a state of being superposed are wound multiple times on the outer circumference thereof, and further to the outermost layer. Wind the exterior film. Metal fine particles are sprayed on both end faces in the axial direction of the cylindrical winding body thus produced to form a metal spraying electrode, and the winding core is pulled out from the cylindrical winding body before spraying. At this stage, a columnar cavity that is open on both sides in the axial direction after the winding core is removed is formed in the axial center portion of the main body portion 1a of the capacitor element.

As shown in FIGS. 1 and 2, the resin outer case 3 has a box shape with an upper opening, and a pair of facing each other in parallel in the Z direction (axial direction of the main body 1a of the capacitor element, horizontal and horizontal direction). A pair of front plate portions 3b and 3b that face each other in parallel with the side plate portions 3a and 3a in the Y direction (horizontal and horizontal directions that intersect vertically in the Z direction) and in the X direction (vertically intersect in the Z direction and the Y direction). It has a bottom plate portion 3c that unfolds flatly in a plane orthogonal to the direction). The side plate portions 3a and 3a are flatly developed along the two-dimensional planes in the X and Y directions, and the front plate portions 3b and 3b are flatly developed along the two-dimensional planes in the Z and X directions. The pair of side plate portions 3a, 3a, the pair of front plate portions 3b, 3b, and the one bottom plate portion 3c are integrally formed of synthetic resin.

As shown in FIG. 3, a gap portion 5 for diffusing the sound wave bundle is formed in each side plate portion 3a. The gap portion 5 develops along a two-dimensional plane in the X direction and the Y direction. The gap portion 5 is sandwiched between _{an inner plate 3a 1} and an outer plate 3a ₂ facing each other in the Z direction in a parallel posture.

The gap portion 5 for diffusing the sound wave bundle is in a positional relationship that intersects with the extension line of the axial center of the capacitor element 1. More specifically, the central portion of the gap portion 5 is located near the extension line of the axial center of the capacitor element 1.

The gap 5 is open upward in the X direction, but is closed in the downward direction in the X direction and closed in both directions in the Y direction. The bottom plate portion 3c covers the entire bottom surface of the outer case 3. The aspect of the gap portion 5 is the same configuration as the pair of side plate portions 3a, 3a.

In FIG. 3, the edge portion (edge portion) is drawn at a right angle with respect to the shape of the gap portion 5, which is a device for clarifying the existence of the gap portion 5. In practice, a curve on a semicircle is drawn as shown in FIGS. 1 and 2. However, the edge portion (edge portion) of the gap portion 5 may be positively made at a right angle.

The exterior case 3 having the above-described form is integrally formed by injection molding of synthetic resin. As the synthetic resin, PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PPS (polyphenylene sulfide) and the like are used.

In the outer case 3, the main body portion 1a of the capacitor element 1 is accommodated from above in the accommodation space portion 3d surrounded by the bottom plate portion 3c, the pair of front plate portions 3b, 3b, and the pair of inner plates 3a ₁ , 3a _1. The axial direction of the main body 1a of the capacitor element is accommodated in a posture along the Z direction of the outer case 3. At this time, the main body 1a of the capacitor element is accommodated in a state where the entire body is contained inside the accommodation space 3d, but the substantially upper half of the pair of positive electrode and negative electrode lead electrodes 2 and 2 is above the accommodation space 3d. It protrudes outward and upward from the opening.

The position of the end portion of the gap portion 5 for diffusing the sound wave bundle in the Y direction coincides with the position of the end portion of the accommodation space portion 3d in the Y direction. The position of the lower end portion of the gap portion 5 in the X direction coincides with the position of the lower end portion of the accommodation space portion 3d in the X direction. The width of the gap portion 5 in the Z direction is uniform over the entire gap portion 5, and the width thereof is substantially the same as the _{width of the inner plate 3a 1} and the outer plate 3a _2. The gap 5 is open to the outside only in the upper direction of the X direction, and is closed in both the lower direction of the X direction, both directions of the Y direction, and both directions of the Z direction.

A sealing resin 4 such as an epoxy resin is filled and solidified in the accommodation space 3d of the outer case 3 (potting), and the sealing resin 4 encloses the main body 1a of the capacitor element and the base side of the extraction electrodes 2 and 2. Has been done. The sealing resin 4 protects the main body 1a of the capacitor element and the connection between the main body 1a and the lead-out electrodes 2 and 2. The sealing resin 4 is also filled in the cylindrical cavity in the axial direction after the winding core is pulled out at the axial center portion of the main body portion 1a.

[Second Example]
A second embodiment of the present invention will be described with reference to FIGS. 4, 5 and 6. FIG. 4 is a perspective view showing a metallized film capacitor according to a second embodiment of the present invention, FIGS. 5 (a), 5 (b) and 5 (c) are a plan view, a front view and a side view thereof, and FIG. 6 (a). , (B) is a perspective view of the main part, and FIG. 6C is a vertical sectional view of the main part. In each of these figures of the second embodiment, the same reference numerals used in each of the figures of the first embodiment refer to the same components, and detailed description thereof will be omitted.

In the second embodiment, the dimension (internal volume) of the gap portion 5 for diffusing the sound wave bundle is expanded as compared with the first embodiment. That is, the width of the gap portion 5 in the Z direction, the width in the Y direction, and the width in the X direction are all wider than those in the first embodiment. However, as in the case of the first embodiment, the gap portion 5 is open to the outside only in the upper direction in the X direction, and is closed in both the downward direction, the Y direction, and the Z direction.

As the width is expanded, the wall thickness of the bottom plate portion 3c located below the gap portion 5 in the X direction is thinner than that of the first embodiment. The wall thickness of the front plate portion 3b located in the Y direction of the gap portion 5 is thinner than that of the first embodiment. The wall thickness of the inner plate 3a ₁ and the outer plate 3a ₂ is also thinner than that of the first embodiment.

Other configurations are the same as in the case of the first embodiment.

In this second embodiment, the width of the gap portion 5 for diffusing the sound wave bundle is expanded (thinning of the plate portion) in any of the three directions of the X direction, the Y direction, and the Z direction. As an embodiment, it may be extended in any one of the three directions, or may be extended in any two of the three directions (the combination is arbitrary).

[Third Example]
A third embodiment of the present invention will be described with reference to FIGS. 7, 8 and 9. 7 is a perspective view showing a metallized film capacitor according to a third embodiment of the present invention, FIGS. 8 (a), 8 (b) and 8 (c) are a plan view, a front view and a side view thereof, and FIG. 9 (a). , (B) is a perspective view of the main part, and FIG. 9 (c) is a vertical sectional view of the main part. In each of these figures of the third embodiment, the same reference numerals used in each of the figures of the first embodiment refer to the same components, and detailed description thereof will be omitted.

In the first embodiment, the direction of opening the gap portion 5 for diffusing the sound wave bundle to the outside is only one side (upward direction) in the X direction, whereas in the third embodiment, the gap portion 5 is opened. The direction of opening to the outside is both sides (upward and downward) in the X direction. This is especially clear in FIGS. 8 (b) and 9 (c). That is, the bottom of the gap 5 is open to the outside (downward). As in the case of the first embodiment, it is in a closed state in both the Y direction and the Z direction.

Other configurations are the same as in the case of the first embodiment.

[Fourth Example]
A fourth embodiment of the present invention will be described with reference to FIGS. 10, 11 and 12. 10 is a perspective view showing a metallized film capacitor according to a fourth embodiment of the present invention, FIGS. 11 (a), 11 (b) and 11 (c) are a plan view, a front view and a side view thereof, and FIG. 12 (a). , (B) is a perspective view of the main part, and FIG. 12 (c) is a vertical sectional view of the main part. In each of these figures of the fourth embodiment, the same reference numerals as those used in the respective figures of the first embodiment refer to the same components, and detailed description thereof will be omitted.

In the fourth embodiment, the directions of opening the gap 5 for diffusing the sound wave bundle to the outside are both sides in the X direction and both sides in the Y direction. As shown in FIG. 12 (c), at the four corners of the gap portion 5, a columnar connecting portion 3e having a small cross-sectional area for connecting (continuously connecting) _{the outer plate 3a 2} to the inner plate 3a ₁ There is. The cross section of these four connecting portions 3e ... Is approximately square in order to make the opening area of the external opening as large as possible, and the vertical and horizontal dimensions thereof are substantially the same as the wall thickness of the front plate portion 3b. ing.

Other configurations are the same as in the case of the first embodiment.

As an embodiment of the modification of the fourth embodiment, a combination of either one side of the X direction and any one side of the Y direction, or a combination of both sides of the X direction and any one side of the Y direction. , Either one side in the X direction and both sides in the Y direction may be combined.

[Fifth Example]
A fifth embodiment of the present invention will be described with reference to FIGS. 13, 14 and 15. 13 is a perspective view showing a metallized film capacitor according to a fifth embodiment of the present invention, FIGS. 14 (a), 14 (b) and 14 (c) are a plan view, a front view and a side view thereof, and FIG. 15 (a). , (B) is a perspective view of the main part, and FIG. 15C is a vertical sectional view of the main part. In each of these figures of the fifth embodiment, the same reference numerals as those used in the drawings of the first embodiment and the fourth embodiment refer to the same components, and detailed description thereof will be omitted.

It is the same as the fourth embodiment in that the direction of opening the gap 5 for diffusing the sound wave bundle to the outside is both sides in the X direction and both sides in the Y direction (see FIG. 15C). The width of the opening in the X direction at the end in the Y direction is narrower than that in the fourth embodiment. The four connecting portions 3e ... for connecting the outer plate 3a ₂ to the inner plate 3a ₁ are vertically longer than in the case of the fourth embodiment. The position of the opening of the gap 5 at the end in the Y direction is the central position in the X direction.

Other configurations are the same as in the case of the first embodiment.

As an embodiment of the modification, the position of the opening of the gap 5 for diffusing the sound wave bundle at the end in the Y direction may be biased upward or downward instead of the central position in the X direction, and the number of openings may be set. It may be 2 or more.

The metallized film capacitors of the above five examples were tested for measuring the intensity-frequency characteristics of noise such as roaring noise. The results are shown in FIGS. 16 (a) and 16 (b) in correspondence with the conventional examples shown in FIGS. 17 and 18. FIG. 16A shows actual measurement data, and FIG. 16B is data normalized by setting all the noise intensities in the conventional example to 0 at each frequency. The frequency range is 7 points (in 0.5 kHz increments) from 10.0 kHz to 13.0 kHz and 11.8 kHz.

In this figure, (1) is the result of the first embodiment (open only in the upward direction), (2) is the result of the second embodiment (open only in the upward direction and is an extended type), and (3) is the third. As a result of the embodiment (opening in both the vertical and horizontal directions), (4) is the result of the fourth embodiment (opening in the vertical and horizontal directions), and (5) is the result of the fifth embodiment (opening in the vertical and horizontal directions and reducing the opening in the horizontal direction). As a result of (type), (0) is the result of the conventional example.

In all of the first to fifth embodiments, it can be seen that the presence of the gap portion 5 for sound wave flux diffusion has the effect of reducing noise such as a growl at each frequency. Further, it can be said that the vertical and horizontal open types (3) and (5) tend to have a better noise reduction effect than (1), (2) and (4).

In any case, the propagation direction of the high-frequency sound wave bundle passing through the _{inner plate 3a 1} is increased due to the presence of the gap portion 5 for diffusing the sound wave bundle formed by the double wall of _{the inner plate 3a 1} and the outer plate 3a _2. Spread. The direction of diffusion of the high-frequency sound wave bundle is a solid angle region having a spread of 360 degrees around the axis of the capacitor element, which is a collection of various directions.

As described above, in the embodiment of the present invention, the high-frequency sound wave bundle propagating along the axial direction from the axial center portion of the main body portion 1a of the capacitor element is widely diffused by the presence of the gap portion 5 for diffusing the sound wave bundle. Therefore, the effect of reducing noise such as howling noise in the axial direction (Z direction) can be made excellent.

In the above embodiment, the main body 1a of the capacitor element is formed into a cylindrical shape, but instead of this, a flat columnar body obtained by compressing and deforming the cylindrical shape inward in the radial direction may be used. However, the closer the element cross section is to a perfect circular shape, the stronger the winding can be performed, which is effective in suppressing noise.

In the above embodiment, the cavity at the center of the main body 1a of the cylindrical capacitor element is filled with the sealing resin, but air may remain there.

The present invention relates to a metallized film capacitor in which the main body of a wound capacitor element is housed in an outer case and then sealed with a resin, in particular, noise such as roaring noise in the axial direction (Z direction) of the capacitor element. It is useful as a technique to improve the reduction effect.

1 Capacitor element 1a Capacitor element body 2 Drawer electrode 3 Exterior case 3a Side plate 3a ₁ Inner plate 3a ₂ Outer plate 4 Encapsulating resin 5 Air gap for sonic bundle diffusion

Claims (4)

A metallized film-wound capacitor element with lead-out electrodes connected to both ends in the axial direction,
A resin outer case that houses the main body of the capacitor element except for a part of the lead-out electrode, and
A metallized film capacitor provided with a sealing resin that is filled in the outer case and covers the main body of the capacitor element by solidification.
The side plates at both ends in the axial direction of the outer case are formed as a double wall of an outer plate and an inner plate facing each other in the axial direction, and are perpendicular to the axial direction between the outer plate and the inner plate. A gap for diffusion of sound wave bundles is formed, which develops in various directions .
The outer case is a metallized film capacitor characterized in that the entire body including the inner plate and the outer plate is integrally molded by injection molding of resin. The metallized film capacitor according to claim 1, wherein the gap portion for diffusing the sound wave bundle is in a positional relationship intersecting with an extension line of the axial center of the capacitor element. The metallized film capacitor according to claim 2, wherein the gap portion for diffusing the sound wave bundle has a central portion located in the vicinity of an extension line of the axial center of the capacitor element. According to any one of claims 1 to 3 , the capacitor element has a cylindrical shape having a hollow axial core, and the hollow of the axial core is also filled with the sealing resin. The metallized film capacitor described.

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