JP6985681B2 - Surface-mounted capacitors and seat plates used for them - Google Patents

Description

The present invention relates to a surface mount type capacitor and a seat plate used therein.

Conventionally, a surface mount type aluminum electrolytic capacitor is surface mounted by a reflow process at the time of substrate mounting. In this reflow mounting, the wiring board itself is exposed to a high temperature equal to or higher than the solder melting temperature for soldering.

In this reflow mounting process, the surface-mounted aluminum electrolytic capacitor itself mounted on the substrate is exposed to a high temperature, so that the electrolytic solution, unreacted monomer, and solvent contained therein are vaporized, and the internal pressure of the capacitor body is increased. Rise. This increase in internal pressure causes expansion of the sealing material that constitutes the capacitor body. Due to this, the sealing material interferes with the seat plate adjacent to the sealing material, and the pressure causes the seat plate to be deformed, which may cause soldering failure.

Therefore, in Patent Document 1, by providing a recess on the side of the seat plate facing the sealing material, the pressure on the seat plate caused by the expansion of the sealing material is reduced.

Japanese Unexamined Patent Publication No. 2008-270338

However, the recess on the surface of the seat plate (insulating plate) of Patent Document 1 has the following problems because the depths on the central portion side and the edge portion side are formed to be constant. That is, in the seat plate (insulating plate) of Patent Document 1, the depth of the recess is suppressed to about 30% with respect to the thickness of the seat plate in order to secure the strength of the seat plate itself while forming the recess. .. Therefore, when the sealing material expands significantly during reflow, there is a possibility that contact between the expansion center of the sealing material (the region where the deformation due to the expansion of the sealing material is large) and the seat plate cannot be reliably avoided. On the other hand, it is conceivable to increase the thickness of the seat plate itself sufficiently to secure the strength of the seat plate while increasing the depth of the recess in order to surely avoid contact with the sealing material. Will increase the cost of the member and will hinder the reduction of the height of the capacitor.

Therefore, the present invention has been made to solve the above-mentioned problems, and is a surface-mounted capacitor capable of avoiding contact between the sealing material and the seat plate due to expansion of the sealing material while suppressing an increase in the thickness of the seat plate. It is an object of the present invention to provide a seat plate used for this.

The surface-mounted capacitor according to the present invention has a capacitor body having a capacitor element, a bottomed tubular storage container for accommodating the capacitor element, and a sealing material for sealing the open end of the storage container, and the capacitor body. The seat plate has a substrate whose surface faces the sealing material of the capacitor body and the capacitor body is arranged on the surface.
On the central portion side of the surface of the substrate, a recess having a depth in the thickness direction of the substrate is formed with respect to the end face portion side, and the recess is formed from the edge portion side of the substrate to the central portion side. toward characterized Rukoto to have a deeper a region in stages.

Further, the seat plate according to the present invention is a seat plate that accommodates a capacitor element and holds a capacitor body sealed with a sealing material, the surface of which faces the sealing material of the capacitor body, and the surface thereof is the surface. It has a substrate on which a capacitor body is placed, and a recess is formed on the central portion side of the surface of the substrate, which is deeper in the thickness direction of the substrate with respect to the edge portion side . It characterized Rukoto to have a stepwise deeper a region from the edge portion side of the substrate toward the central portion.

According to such a configuration (surface mount type capacitor and seat plate), even if the sealing material expands significantly, the depth in the substrate thickness direction is increased on the center side of the substrate surface of the seat plate with respect to the edge portion side. Since the deep recess is formed, it is possible to avoid contact between the sealing material and the seat plate. Moreover, since the depth of the recesses on the edge side of the substrate that does not face the expansion center of the sealing material is shallower than that on the center side, the thickness of the substrate is relatively secured. As a result, it is possible to suppress the deformation of the seat plate due to the expansion of the sealing material while suppressing the increase in the thickness of the seat plate. Further, since the concave portion has a region that gradually becomes deeper from the edge portion side to the central portion side of the substrate, the depth of the concave portion is adjusted according to the degree of expansion of the sealing material, and the expansion of the sealing material causes the recess. It is possible to avoid contact between the sealing material and the seat plate.

In this surface-mounted capacitor and seat plate, even if the sealing material expands significantly, a recess is formed on the central portion side of the substrate surface of the seat plate, which is deeper in the substrate thickness direction with respect to the edge portion side. , Contact between the sealing material and the seat plate can be avoided as much as possible. Moreover, since the depth of the recesses on the edge side of the substrate that does not face the expansion center of the sealing material is shallower than that on the center side, the thickness of the substrate is relatively secured. As a result, it is possible to suppress the deformation of the seat plate due to the expansion of the sealing material while suppressing the increase in the thickness of the seat plate. Further, since the concave portion has a region that gradually becomes deeper from the edge portion side to the central portion side of the substrate, the depth of the concave portion is adjusted according to the degree of expansion of the sealing material, and the expansion of the sealing material causes the recess. It is possible to avoid contact between the sealing material and the seat plate.

It is an upper perspective view which shows the capacitor main body and a seat plate which concerns on embodiment of this invention. It is a lower perspective view which shows the capacitor main body and a seat plate which concerns on embodiment of this invention. It is an enlarged perspective view which shows the seat plate of FIG. It is a top view which shows the seat plate of FIG. FIG. 6 is a sectional view taken along line VV of FIG. It is an enlarged sectional view which shows the concave part of FIG. It is an enlarged sectional view which shows the concave part which concerns on the modification 1. It is an enlarged sectional view which shows the concave part which concerns on the modification 2.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, the surface-mounted capacitor 1 according to the present embodiment has a capacitor body 10 having a substantially cylindrical shape and a seat plate 20 for holding the capacitor body 10. The capacitor main body 10 is composed of a wound capacitor element (not shown), a bottomed cylindrical storage container 11 for accommodating the capacitor element, and a sealing material 12 for sealing the open end of the storage container 11. ing. Further, the seat plate 20 is formed along the central axis C of the capacitor body 10 so as to surround the substrate 22 on which the two insertion holes 21 are formed and the bottom surface of the capacitor body 10 abuts and the outer peripheral surface of the capacitor body 10. It is composed of four extending side walls 35.

The capacitor body 10 having a cylindrical shape accommodates a capacitor element inside a substantially cylindrical storage container 11, and after inserting a sealing material 12 at the open end thereof, a groove portion 13 is formed near the lower portion of the outer peripheral side surface. By crimping in this way, the accommodating container 11 is sealed by the sealing material 12. The sealing material 12 expands toward the seat plate 20 by being exposed to a high temperature, for example, in a reflow mounting process. The capacitor body 10 is provided with two lead terminals 14 so as to penetrate the sealing material 12. Each lead terminal 14 is connected to a tab (not shown) derived from a capacitor element, for example, by welding.

The condenser element may be formed by winding an anode foil made of a valve metal such as aluminum with a separator interposed therebetween and impregnated with an electrolytic solution, or may be a solid conductive element as an electrolyte. A solid electrolytic capacitor element or the like in which a polymer is formed between an anode foil and a cathode foil made of a valve metal such as aluminum can be used.

The seat plate 20 is made of a material having electrical insulation. In the present embodiment, the material of the seat plate 20 is resin. As described above, the surface of the seat plate 20 faces the sealing material 12 of the capacitor body 10, and the substrate 22 on which the capacitor body 10 is arranged on the surface and the four side walls sandwiching the storage container 11 of the capacitor body 10 are sandwiched. It is composed of 35 (see FIG. 3).

The substrate 22 has a predetermined wall thickness and, as shown in FIG. 4, has a substantially square shape when viewed from above. The substrate 22 is formed with a recess 24 having a contact surface 22a with the capacitor body 10 recessed around the central axis C on the side of the capacitor body 10 facing the sealing material 12. The recess 24 is formed on the central portion side of the surface of the substrate 22 so that the depth of the substrate 22 in the thickness direction is deeper than that of the end face portion side. In the state where the seat plate 20 holds the capacitor main body 10, the central axis C of the capacitor main body 10 and the central axis C of the substrate 22 (recessed portion 24) coincide with each other.

The recess 24 is circular when viewed from above, and has a region that becomes deeper from the edge portion side of the substrate 22 toward the center portion side. The fact that the concave portion 24 becomes deeper from the edge portion side toward the central portion means that the concave portion 24 faces the central portion side in addition to the configuration of the present embodiment in which the concave portion 24 continuously deepens toward the central portion side. It includes the configuration of the modified example 1 described later, which gradually becomes deeper. As a result, the depth of the recess 24 can be adjusted according to the degree of expansion of the sealing material 12, and contact between the sealing material 12 and the seat plate 20 due to the expansion of the sealing material 12 can be avoided. As shown in FIG. 5, the two inclined surfaces 31 and 32, which are regions (outer peripheral surfaces) defining the recess 24, have different inclination angles. Specifically, the recess 24 is formed on the bottom surface 25 formed in the central portion of the surface of the substrate 22, the first inclined surface 31 rising from the outer peripheral edge of the bottom surface 25, and the first inclined surface 31 formed radially outside the first inclined surface 31. It is defined from the two inclined surfaces 32.

The bottom surface 25 has a circular top view, and has a protrusion 26 formed at the center thereof and an insertion hole 21 formed radially outward of the protrusion 26. The protruding portion 26 has a concentric circle with the concave portion 24 when viewed from above, and protrudes toward the capacitor main body 10. As shown in FIG. 6, the wall thickness between the bottom surface 25 and the back surface 22b (the surface opposite to the contact surface 22a) of the substrate 22 is the wall thickness between the first inclined surface 31 and the back surface 22b. It is thinner than the wall thickness between the second inclined surface 32 and the back surface 22b.

The first inclined surface 31 has a ring shape when viewed from above, and is formed between the bottom surface 25 and the second inclined surface 32, that is, radially outward from the bottom surface 25 and radially inward from the second inclined surface 32. There is. The first inclined surface 31 extends from the outer peripheral edge of the bottom surface 25 toward the capacitor main body 10 so as to be inclined toward the edge portion side of the substrate 22. That is, the first inclined surface 31 constitutes a side surface of a truncated cone whose diameter increases outward in the radial direction. The inclination angle of the first inclined surface 31 with respect to the bottom surface 25 is θ1. Therefore, the depth of the first inclined surface 31 is continuously deepened from the radial outer side toward the central portion, and the wall thickness between the first inclined surface 31 and the back surface 22b is toward the central portion side. It becomes thinner continuously.

Like the first inclined surface 31, the second inclined surface 32 has a ring shape when viewed from the top surface, and is formed radially outward from the bottom surface 25 and the first inclined surface 31. The second inclined surface 32 extends from the outer peripheral edge of the first inclined surface 31 toward the capacitor main body 10 so as to be inclined toward the edge portion side of the substrate 22. That is, the second inclined surface 32 constitutes a side surface of a truncated cone whose diameter increases outward in the radial direction. The inclination angle of the second inclined surface 32 with respect to the bottom surface 25 is θ2. Therefore, the depth of the second inclined surface 32 is continuously deepened from the radial outer side toward the central portion, and the wall thickness between the second inclined surface 32 and the back surface 22b is toward the central portion side. It becomes thinner continuously. The inclination angle θ2 makes the inclination angle of the first inclined surface 31 smaller than θ1.

The two insertion holes 21 formed in the bottom surface 25 of the recess 24 penetrate from the contact surface 22a to the back surface 22b. The two insertion holes 21 are formed near the central portion of the substrate 22 when viewed from above. Two lead terminals 14 provided in the capacitor main body 10 are inserted into the two insertion holes 21. The back surface 22b of the substrate 22 has two groove portions 29 (see FIG. 2) having a depth substantially equal to the wall thickness of the lead terminal 14 so that the lead terminal 14 can be accommodated from the two insertion holes 21 to the outer end portion. ) Is formed. The two groove portions 29 extend radially outward from the central axis C.

As described above, the two lead terminals 14 drawn from the sealing material 12 of the capacitor main body 10 are inserted into the two insertion holes 21 and bent outward along each groove 29. As a result, the substrate 22 is sandwiched between the capacitor main body 10 and the bent lead terminal 14, and is integrated with the capacitor main body 10. At this time, in the two lead terminals 14, the portion exposed on the back surface 22b of the substrate 22 is housed in the groove portion 29 and does not protrude. Therefore, the surface-mounted capacitor 1 can stand on its own with the back surface 22b as the mounting surface.

The side walls 35 are erected near the four corners of the substrate 22 (edges on the surface of the substrate 22). The four side walls 35 have the same shape as each other. Further, the four side walls 35 are arranged so that the distances from the central axis C of the capacitor main body 10 are equal to each other. Further, four side walls 35 are arranged at equal angular intervals in the circumferential direction with respect to the central axis C. The four side walls 35 have a first arc plane which is a part of a first circumference having a center axis C of the capacitor main body 10 and a radius larger than that of the capacitor main body 10 on the inner side surface. Further, the four side walls 35 have a second arc surface on the outer surface, which is a part of the second circumference which is concentric with the first circumference and has a radius larger than the first circumference. In each side wall 35, the wall thickness of the portion sandwiched between these two arc surfaces is uniform. When the seat plate 20 holds the capacitor body 10, the entire inner surface of each side wall 35 is in contact with the outer peripheral surface of the capacitor body 10.

The seat plate 20 as described above is generally manufactured by injection molding. Therefore, as in the present embodiment, the uniform wall thickness of the side wall 35 can further prevent the occurrence of distortion and warpage. The four side walls 35 do not have to have a portion having a uniform wall thickness.

In order to hold the capacitor body 10 on the seat plate 20, the capacitor body 10 is further pushed downward from the state shown in FIG. At this time, the side wall 35 made of resin is elastically deformed outward along the outer peripheral surface of the capacitor body 10 by being pushed outward in the radial direction by the capacitor body 10.

In the state where the seat plate 20 holds the capacitor main body 10, the capacitor main body 10 is pressed by the inner side surfaces of the four side walls 35 in the direction toward the central axis C thereof. As a result, the capacitor body 10 is firmly sandwiched by the seat plate 20.

Further, since the side wall 35 made of resin can be elastically deformed in the direction of contact with the capacitor body 10, even if the outer shape of the capacitor body 10 and / or the side wall 35 is distorted, the amount of deformation is less than a predetermined range. Even if it is deformed, the side wall 35 elastically deforms in both the radial direction and the inside and outside following the deformation. Therefore, in the present embodiment, it is guaranteed that the inner side surface of each side wall 35 is in contact with the outer peripheral surface of the capacitor body 10.

[Characteristics of the surface-mounted capacitor 1 of this embodiment]
The surface-mounted capacitor 1 of the present embodiment has the following features.

In the surface-mounted capacitor 1 of the present embodiment, even if the sealing material 12 expands significantly, the depth of the substrate 22 in the thickness direction with respect to the edge portion side on the central portion side of the surface of the substrate 22 of the seat plate 20 Since the deep recess 24 is formed, contact between the sealing material 12 and the seat plate 20 can be reliably avoided as much as possible. Moreover, since the depth of the recess 24 is shallower on the edge side of the substrate 22 that does not face the expansion center of the sealing material 12 than in the center, the thickness of the substrate 22 is relatively secured. As a result, it is possible to suppress the deformation of the seat plate 20 due to the expansion of the sealing material 12 while suppressing the increase in the thickness of the seat plate 20. Therefore, soldering defects can be reliably prevented. Since the seat plate 20 has a small thin portion and the recess 24 has a structure in which the seat plate 20 becomes thinner toward the center, the risk of molding defects due to injection molding can be reduced.

In the surface-mounted capacitor 1 of the present embodiment, the region defining the concave portion 24 extends from the central portion of the concave portion 24 to the edge portion, and is formed by a plurality of inclined surfaces 31 and 32 having different inclination angles. Thereby, the recess 24 can be formed with a simple structure.

In the surface-mounted capacitor 1 of the present embodiment, the inclination angle θ2 of the second inclined surface 32 with respect to the bottom surface 25 is smaller than the inclination angle θ1 of the first inclined surface 31 with respect to the bottom surface 25. As a result, while suppressing the thinning of the wall thickness of the substrate 22 in the portion where the second inclined surface 32 is formed and ensuring the strength of the seat plate 20, the sealing material 12 and the seat plate 20 due to the expansion of the sealing material 12 Contact can be avoided.

In the surface-mounted capacitor 1 of the present embodiment, a protruding portion 26 projecting toward the capacitor body 10 is formed at the center of the recess 24. Thereby, the strength of the seat plate 20 can be increased.

Next, a modification of the surface-mounted capacitor 1 of the embodiment will be described. In the modified example, the shape of the capacitor main body 10 is the same as that of the above embodiment, so the description thereof will be omitted. Further, only the portion different from the above embodiment with respect to the shape of the seat plate 20 will be described, and since the shapes of the other portions are the same as those of the above embodiment, the same reference numerals are given and the description thereof will be omitted.

<Modification 1>
In the above embodiment, the recess 24 is defined by the first inclined surface 31 and the second inclined surface 32 having different inclination angles. However, in the modified example 1 shown in FIG. 7, the cross-sectional shape of the outer peripheral surface defining the recess 40 in the thickness direction along the central axis C is stepped.

The recess 40 according to the first modification is defined by a bottom surface 25, a first step portion 41 rising from the bottom surface 25, and a second step portion 45 formed radially outside the first step portion 41. The first-stage portion 41 and the second-stage portion 45 form the outer peripheral surface of the recess 40. The first step portion 41 has a first side surface 42 extending upward from the outer peripheral edge of the bottom surface 25 toward the capacitor main body 10, and a first bearing surface extending radially outward from the upper end of the first side surface 42 in parallel with the bottom surface 25. It consists of 43. The second step portion 45 has a second side surface 46 extending upward from the outer peripheral edge of the first seat surface 43 toward the capacitor main body 10, and a second side surface 46 extending radially outward from the upper end of the second side surface 46 in parallel with the bottom surface 25. It is composed of two seat surfaces 47 and a third side surface 48 extending upward from the outer peripheral edge of the second seat surface 47 toward the capacitor main body 10. With this configuration, the recess 40 gradually becomes deeper from the radial outer side toward the central portion side, and the recess can be formed with a simple configuration.

<Modification 2>
In the second modification shown in FIG. 8, the recess 50 is defined by one inclined surface 51 extending from the edge of the recess 50 to the bottom. The recess 50 according to the second modification has a bottom surface 25 and an inclined surface 51 extending radially outward from the outer peripheral edge of the bottom surface 25 toward the capacitor main body 10. The inclined surface 51 constitutes a side surface of a truncated cone whose diameter increases outward in the radial direction. As a result, the concave portion 50 becomes continuously deeper from the radial outer side toward the central portion side, and the concave portion 50 can be formed with a simple configuration.

Although the embodiments of the present invention have been described above with reference to the drawings, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present invention is shown not only by the description of the above-described embodiment but also by the scope of claims, and further includes all modifications within the meaning and scope equivalent to the scope of claims.

In the above embodiment, the recess 24 is defined by one or a plurality of inclined surfaces, but the present invention is not limited to this, and the recess 24 may be defined by, for example, a bowl-shaped curved surface.

In the above embodiment, the protrusion 26 is provided at the center of the recess 24, but the protrusion 26 may not be provided. As a result, even if the sealing material 12 expands, interference between the sealing material 12 and the seat plate 20 can be reliably avoided. Further, the inclination angle of the outer peripheral surface defining the recess 24 is not particularly limited.

1-side mount type capacitor 10 Capacitor body 11 Containing container 12 Sealing material 20 Seat plate 22 Board 24 Recess 25 Bottom surface 26 Protruding part 31 1st inclined surface 32 2nd inclined surface 35 Side wall 40 Recess (deformation example 1)
41 1st step 45 2nd step 50 Recessed part (deformation example 2)
51 Inclined surface C Central axis

Claims (7)

A capacitor body having a capacitor element, a bottomed cylindrical storage container for accommodating the capacitor element, and a sealing material for sealing the open end of the storage container.
The seat plate that holds the capacitor body and
Equipped with
The seat plate has a substrate whose surface faces the sealing material of the capacitor body and the capacitor body is arranged on the surface.
A recess having a depth in the thickness direction of the substrate is formed on the central portion side of the substrate surface with respect to the edge portion side .
The recess, surface mount capacitors, wherein Rukoto to have a region consisting stepwise deeper toward the center side from the edge portion of the substrate. The surface-mounted capacitor according to claim 1, wherein the seat plate is erected on an edge portion of the surface of the substrate and has a plurality of side walls that sandwich the accommodating container of the capacitor body. The surface-mounted capacitor according to claim 1 or 2 , wherein the region defining the recess has a stepped cross-sectional shape in the thickness direction of the substrate. The surface-mounted capacitor according to claim 1 or 2 , wherein the region defining the recess is formed by one inclined surface extending from the center portion of the recess to the edge portion. The surface mount type according to claim 1 or 2 , wherein the region defining the recess is formed by a plurality of inclined surfaces having different inclination angles extending from the center portion of the recess to the edge portion. Capacitor. The concave surface has a circular bottom surface formed on the central portion side of the substrate surface, a first inclined surface extending inclined from the outer peripheral edge of the bottom surface toward the edge portion side of the substrate, and the first inclined surface. It has a second inclined surface extending inclined from the outer peripheral edge of the surface toward the edge portion side of the substrate.
The surface-mounted capacitor according to claim 5 , wherein the inclination angle of the second inclined surface with respect to the bottom surface is smaller than the inclination angle of the first inclined surface with respect to the bottom surface. A seat plate that houses a capacitor element and holds the capacitor body sealed with a sealing material.
The surface of the capacitor faces the sealing material of the capacitor body, and the surface has a substrate on which the capacitor body is placed.
A recess having a depth in the thickness direction of the substrate is formed on the central portion side of the substrate surface with respect to the edge portion side .
The recess, the seat plate, characterized in Rukoto to have a stepwise deeper a region from the edge portion side of the substrate toward the central portion.

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