A capacitor and a circuit board on which it is mounted.

Abstract

During the molding process, this prevents the sealing body from being pushed into the case by the flowing molding resin. [Solution] A pressure receiving plate 12 is placed on the side of the sealing body 5 facing the opening 2 of the case 3. The outer circumference of the side of the pressure receiving plate 12 facing the base plate 6 is covered by the bent portion 11 of the case 3 when viewed from the side of the opening 2 of the case 3. On the side of the pressure receiving plate 12 facing the base plate 6, a base portion 18 is provided on the inner side of the portion covered by the bent portion 11 of the case 3, protruding toward the opening 2 of the case 3 toward the base plate 6. The connecting terminal 9 is configured to extend beyond the opening 2 of the case 3, passing through the base portion 18 of the pressure receiving plate 12. The pressure receiving plate 12 is made of a laser light absorbing material, and the base plate 6 is made of a laser light transmitting material. The surface of the base portion 18 of the pressure receiving plate 12 and the surface of the base plate 6 facing the pressure receiving plate 12 are brought into contact, and these contact surfaces are connected by laser welding.

Description

Technical Field

[0001] The present invention relates to a capacitor and a capacitor mounting circuit board on which the capacitor is mounted.

Background Art

[0002] In a capacitor mounting circuit board in which a capacitor is mounted together with other components on the surface side of a circuit board, a structure has been proposed in which the surface side of the circuit board is covered with a molding resin to protect the capacitor and other components from heat and impact (for example, Patent Document 1 below).

[0003] This prior document mentions, as a problem in the case of covering a capacitor and other components with a molding resin, that the case constituting the capacitor receives pressure from the molding resin and is deformed.

[0004] That is, the capacitor has a cylindrical case with one end side being an opening, a capacitor element housed in this case, a sealing body mounted on the side of the opening rather than the capacitor element in the case, and a seat plate arranged opposite to the sealing body outside the opening side of the case. In order to prevent the side surface of the case from deforming inward due to the pressure of the flowing molding resin during mold molding, a silicon pressure absorbing member is provided on the outer peripheral surface of the case.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The aforementioned prior literature focuses on the inward deformation of the case sides due to the molding resin, but in reality, the bigger problem is that the sealing body installed on the opening side inside the case is pushed into the case by the pressure of the flowing molding resin during molding, rather than the deformation of the case itself.

[0007] In other words, the sealing element is a constricted part of the case that deforms inward to create an airtight seal inside the case, so it is essential that it be made of an elastic material.

[0008] Therefore, if the pressure of the flowing mold resin during the above-mentioned molding process is applied to the sealing body exposed to the outside of the case at the case opening, this sealing body may elastically deform, be pushed into the case, and potentially damage the capacitor element.

[0009] Therefore, the present invention aims to prevent the sealing body from being pushed into the case by the flowing mold resin during mold molding. [Means for solving the problem]

[0010] To achieve this objective, the capacitor of the present invention comprises a cylindrical case with an opening at one end, a capacitor element housed within the case, a sealing body made of an elastic material mounted within the case on the side of the capacitor element closer to the opening, and a seat plate positioned opposite the sealing body on the outside of the case on the opening side. The capacitor element has a connection terminal that penetrates the sealing body and extends to the seat plate outside the opening. The outer periphery of the case, corresponding to the outer periphery of the sealing body, is provided with a constricted portion that narrows toward the outer periphery of the sealing body. The end of the case on the opening side is provided with a bent portion that is bent in the direction of the inner circumference of the case. In such a capacitor, a pressure receiving plate is placed on the surface of the sealing body on the opening side of the case, and the outer periphery of the surface of the pressure receiving plate on the seat plate side is covered by the bent portion of the case when viewed from the opening side. A base portion is provided on the inner side of the portion covered by the bent portion on the seat plate side surface of the pressure receiving plate, projecting from the opening toward the seat plate side. The connecting terminal is configured to extend through the base portion and out of the opening, and the pressure receiving plate is made of a laser light absorbing material, and the surface of the pressure receiving plate toward the base portion and the surface of the seat plate toward the pressure receiving plate are in contact, and the contact surfaces of the pressure receiving plate and the seat plate are joined together by laser welding.

[0011] Furthermore, in the capacitor with the above configuration, a recess is formed on the side of the base plate opposite to the pressure receiving plate, and the connection between the pressure receiving plate and the base plate is welded by a laser irradiated into the recess.

[0012] Furthermore, in the capacitor mounting circuit board of the present invention, the capacitor having the above configuration is mounted on the surface of the circuit board, and on the surface of the circuit board, at least the part of the capacitor closer to the circuit board than the constricted portion, and the base plate are covered with molded resin. [Effects of the Invention]

[0013] As described above, the capacitor of the present invention has a pressure receiving plate placed on the opening side of the case of the sealing body, and the outer circumference of the base plate side of the pressure receiving plate is covered by the bent portion of the case when viewed from the opening side of the case, and on the inside of the portion of the base plate side of the pressure receiving plate that is covered by the bent portion of the case, a base portion is provided that protrudes toward the base plate side of the case opening, and the connection terminals of the capacitor element are configured to extend outside the opening of the case, passing through the base portion of the pressure receiving plate.

[0014] Furthermore, the pressure receiving plate is made of a laser light absorbing material, and the base plate is made of a laser light transmitting material. The base surface of the pressure receiving plate and the surface of the base plate on the pressure receiving plate side are in contact, and these contact surfaces are connected by laser welding. This configuration prevents the sealing body from being pushed into the case by the flowing mold resin during molding.

[0015] In other words, in this invention, a pressure receiving plate is placed on the opening side of the case of the sealing body, and the base surface of this pressure receiving plate and the pressure receiving plate side surface of the seat plate are brought into contact, and these contact surfaces are connected by laser welding.

[0016] Therefore, during mold molding, even if the flowing mold resin attempts to push against the pressure receiving plate, the pressure receiving plate is connected to and fixed to the base plate, and the base plate abuts against the opening of the case. As a result, the pressure receiving plate cannot be pushed towards the sealing body, and damage to the capacitor element can be prevented. [Brief explanation of the drawing]

[0017] [Figure 1] Front view of a capacitor according to one embodiment of the present invention [Figure 2] Same, a perspective view of the bottom of the capacitor. [Figure 3] Cross-sectional view of the capacitor. [Figure 4] Disassembled perspective view of the capacitor. [Figure 5]Front view showing the state where the capacitor element, the sealing body, and the pressure receiving plate of the capacitor are combined [Figure 6] Cross-sectional view showing the state where the capacitor element, the sealing body, and the pressure receiving plate of the capacitor are combined [Figure 7] Front side perspective view of the sealing body of the capacitor [Figure 8] Back side perspective view of the sealing body of the capacitor [Figure 9] Front side perspective view of the pressure receiving plate of the capacitor [Figure 10] Back side perspective view of the pressure receiving plate of the capacitor [Figure 11] Front view showing the sealing body and the pressure receiving plate of the capacitor combined [Figure 12] Cross-sectional view showing the sealing body and the pressure receiving plate of the capacitor combined [Figure 13] Front side perspective view of the seat plate of the capacitor [Figure 14] Back side perspective view of the seat plate of the capacitor [Figure 15] Perspective view showing the manufacturing method of the capacitor [Figure 16] Cross-sectional view showing the manufacturing method of the capacitor [Figure 17] Cross-sectional view showing the manufacturing method of the capacitor

Mode for Carrying Out the Invention

[0018] (Embodiment 1) Hereinafter, an embodiment of the present invention will be described.

[0019] As shown in FIGS. 1 to 4, the capacitor 1 of the present embodiment is made of aluminum and includes a cylindrical case 3 having an opening 2 at one end, a capacitor element 4 housed in the case 3, a disk-shaped sealing body 5 made of an elastic material and mounted on the side of the opening 2 rather than the capacitor element 4 in the case 3, and a seat plate 6 disposed opposite to the sealing body 5 outside the opening 2 side of the case 3.

[0020] As is well known, the capacitor element 4 is cylindrical in shape, formed by overlapping a strip-shaped anode foil (not shown) and a strip-shaped cathode foil (not shown) with a strip-shaped separator in between, and then winding them up.

[0021] Furthermore, this capacitor element 4 passes through the through-hole 7 of the sealing body 5 and extends to the base plate 6 outside the opening 2 of the case 3, then passes through the through-hole 8 of the base plate 6 as shown in Figure 16, and then has a connection terminal 9 that is bent outward on the lower surface side of the base plate 6 as shown in Figures 1 to 3.

[0022] Furthermore, the outer circumference of the case 3, which corresponds to the outer circumference of the sealing body 5, is provided with a constricted portion 10 that narrows toward the outer circumference of the sealing body 5, as shown in Figure 3. In addition, the end of the case 3 on the opening 2 side is provided with a bent portion 11 that is bent in the inward direction of the case 3, as shown in Figure 3.

[0023] The above configuration is the same as that of the conventional example, and the features of this embodiment will be described below.

[0024] In this embodiment, as shown in Figure 3, a disc-shaped pressure receiving plate 12 made of synthetic resin is placed on the side of the sealing body 5 facing the opening 2 of the case 3.

[0025] The connection terminal 9 of the capacitor element 4 extends through the through-hole 13 of the pressure receiving plate 12 and out of the opening 2 of the case 3.

[0026] In other words, the connection terminal 9 of this capacitor element 4 first passes through the through hole 7 of the sealing body 5, then through the through hole 13 of the pressure receiving plate 12, then through the through hole 8 of the base plate 6, and then, as shown in Figures 1 to 3, it is bent outward on the lower surface side of the base plate 6.

[0027] Furthermore, as shown in Figure 3, on the side of the pressure receiving plate 12 facing the opening 2 of the case 3, the outer circumference of the through hole 13 through which the connection terminal 9 passes is covered by the bent portion 11 of the case 3 when viewed from the opening 2 side of the case 3.

[0028] Let's continue with a further explanation of the pressure receiving plate 12 and the sealing body 5.

[0029] Both the pressure receiving plate 12 and the sealing body 5 are disc-shaped, but as shown in Figures 3, 5, 6, 11, and 12, the outer diameter of the pressure receiving plate 12 is smaller than that of the sealing body 5. Furthermore, as shown in Figure 3, on the side of the pressure receiving plate 12 facing the opening 2 of the case 3, the outer circumference of the through-hole 13 through which the connection terminal 9 passes is covered by the bent portion 11 of the case 3 when viewed from the opening 2 side of the case 3. In other words, the pressure receiving plate 12 and the sealing body 5 are structured in such a way that movement outside the opening 2 is prevented by the bent portion 11.

[0030] Furthermore, the outer circumference of the pressure receiving plate 12 is larger than the inner circumference of the constricted portion 10 of the case 3, which prevents the pressure receiving plate 12 from moving towards the capacitor element 4 while pressing against the sealing body 5.

[0031] It is not necessary to firmly fix the pressure receiving plate 12 and the sealing body 5, but it is necessary to align them.

[0032] This is because, as described above, the connection terminal 9 of the capacitor element 4 must first pass through the through hole 7 of the sealing body 5, and then through the through hole 13 of the pressure receiving plate 12.

[0033] To this end, in this embodiment, as shown in Figures 7 to 10, a projection 14 is provided on the upper surface of the pressure receiving plate 12 (the surface facing the sealing body 5), and a groove 15 is provided on the lower surface of the sealing body 5 (the surface facing the pressure receiving plate 12). By fitting these projections 14 and grooves 15 together, the pressure receiving plate 12 and the sealing body 5 are positioned as shown in Figures 11 and 12.

[0034] Furthermore, as shown in Figure 8, the groove 15 of the sealing body 5 is rectangular in shape, extending between the left and right through holes 7 in a direction perpendicular to the line connecting these two through holes 7.

[0035] Furthermore, to match the shape of this groove 15, the projection 14 of the pressure receiving plate 12 was also made rectangular, as shown in Figure 9.

[0036] However, both the long-side and short-side dimensions of the projection 14 of the pressure receiving plate 12 are slightly shorter than the long-side and short-side dimensions of the corresponding groove 15 of the sealing body 5.

[0037] Furthermore, the height dimension of the projection 14 of the pressure receiving plate 12 is smaller than the depth dimension of the groove 15 of the sealing body 5.

[0038] In the configuration described above, as shown in Figure 8, the inner wall portion of the groove 15 of the sealing body 5 is provided with a portion 15a where the width between the inner walls is slightly narrower than the dimension in the short side direction of the projection 14 of the pressure receiving plate 12.

[0039] As a result, when the projection 14 of the pressure receiving plate 12 is fitted into the groove 15 of the sealing body 5, the two can maintain the integrated state shown in Figures 11 and 12, thereby improving convenience during production.

[0040] Furthermore, the inner wall portion of the groove 15 of the sealing body 5 has a portion 15a where the width between the inner walls is slightly narrower than the dimension in the short side direction of the projection 14 of the pressure receiving plate 12. However, when the two are fitted together, because the sealing body 5 is made of an elastic material, the opening edge of the groove 15 of the sealing body 5 widens, thereby allowing the projection 14 of the pressure receiving plate 12 to fit properly into the groove 15 of the sealing body 5, and holding the two together in the integrated state shown in Figures 11 and 12.

[0041] Next, I will explain the pressure receiving plate 12 and the seat plate 6.

[0042] As described above, the outer periphery of the surface of the pressure receiving plate 12 on the seat plate 6 side is covered by the bent portion 11 of the case 3, as shown in Figures 3 and 17, when viewed from the opening 2 side of the case 3.

[0043] Furthermore, on the side of the pressure receiving plate 12 facing the seat plate 6, a base portion 18 is provided on the inner side of the portion covered by the bent portion 11 of the case 3, as shown in Figure 17, which protrudes from the opening 2 of the case 3 toward the seat plate 6. The connection terminals 9 of the capacitor element 4 will also pass through the base portion 18 of the pressure receiving plate 12.

[0044] As shown in Figures 5 and 6, the surface of the base portion 18 on the side of the seat plate 6 is flat, and the corresponding surface of the seat plate 6 on the side of the pressure receiving plate 12 is also flat, as shown in Figure 13.

[0045] In other words, as shown in Figures 3 and 17, the surface of the base 18 on the side of the seat plate 6 and the surface of the seat plate 6 on the side of the pressure receiving plate 12 are flat surfaces and are in flat contact with each other.

[0046] On the other hand, on the side of the seat plate 6 opposite to the pressure receiving plate 12, which corresponds to the base portion 18 of the pressure receiving plate 12, a recess 19 for the laser irradiation position is provided, as shown in Figure 14, which is recessed toward the base portion 18 of the pressure receiving plate 12. When viewed from above, the recess 19 is shaped perpendicular to the line connecting the through holes 8 for the connection terminals 9, and by increasing the area on both sides of it, the laser welding area between the base portion 18 of the pressure receiving plate 12 and the seat plate 6 is increased.

[0047] Furthermore, the pressure receiving plate 12 is made of a laser light absorbing material, and the seat plate 6 is made of a laser light transmitting material.

[0048] In other words, in this embodiment, the surface of the base portion 18 on the side of the seat plate 6 and the surface of the seat plate 6 on the side of the pressure receiving plate 12 are brought into flat contact, and then the seat plate 6 and the pressure receiving plate 12 are welded together at their flat contact point by laser irradiation from the recessed portion 19 side of the seat plate 6.

[0049] The seat plate 6 and the pressure receiving plate 12 can be formed from PPS (polyphenylene sulfide) resin, PPA (polyphthalamide) resin, LCP (liquid crystal polymer) resin, etc.

[0050] If the seat plate 6 is formed from a laser light-transmitting material, it should be transparent.

[0051] Furthermore, if the pressure receiving plate 12 is formed from a laser light absorbing material, it will be made black.

[0052] When heat-welding the pressure receiving plate 12 and the seat plate 6 by irradiating them with laser light, it is preferable to make the pressure receiving plate 12 and the seat plate 6 from LCP (liquid crystal polymer) resin from the viewpoint of heat resistance.

[0053] For example, the seat plate 6 is formed from E6008 as an LCP (liquid crystal polymer) resin.

[0054] Furthermore, the pressure receiving plate 12 is formed from E6008B, which is an LCP (liquid crystal polymer) resin.

[0055] The assembly procedure for capacitor 1 will be explained below.

[0056] First, as shown in Figures 11 and 12, the sealing body 5 and the pressure receiving plate 12 are integrated. Next, as shown in Figures 5 and 6, the connection terminals 9 of the capacitor element 4 are made to pass through both the sealing body 5 and the pressure receiving plate 12.

[0057] Next, the capacitor element 4 is inserted through the opening 2 of the case 3, leaving the connection terminals 9 of the capacitor element 4 protruding outside the case 3.

[0058] Next, as shown in Figure 16, a constricted portion 10 is provided on the outer circumference of the case 3, corresponding to the outer circumference of the sealing body 5, and then a bent portion 11 is provided at the end of the case 3 on the opening 2 side, which is bent in the direction of the inner circumference of the case 3. Note that this work is performed with the seat plate 6 not attached, as shown in Figure 16.

[0059] Next, as shown in Figures 15 to 17, the seat plate 6 is attached to the opening 2 side of the case 3, and the surface of the base portion 18 of the pressure receiving plate 12 on the seat plate 6 side and the surface of the seat plate 6 on the pressure receiving plate 12 side are brought into flat contact. Then, by irradiating with a laser from the recessed portion 19 side of the seat plate 6, the seat plate 6 and the pressure receiving plate 12 are laser-welded at their flat contact point.

[0060] Next, as shown in Figures 1 to 3, the tip of the connector terminal 9 is bent to the left and right. In this state, the base plate 6 is in contact with (or very close to) the opening 2 of the case 3, just as in the conventional method. In other words, as its name suggests, the base plate 6 is designed so that the bottom surface of the case 3 rests on its upper surface, allowing the capacitor 1 with the case 3 to be surface-mounted onto a circuit board (not shown), so the base plate 6 is in contact with (or very close to) the opening 2 of the case 3.

[0061] In this embodiment, the capacitor 1, configured as described above, has a pressure receiving plate 12 positioned on the side of the opening 2 of the case 3 of the sealing body 5. The surface of the base portion 18 of the pressure receiving plate 12 on the side of the base plate 6 and the surface of the base plate 6 on the side of the pressure receiving plate 12 are in flat contact, and the base plate 6 and the pressure receiving plate 12 are welded together at the flat contact point by laser irradiation, thus connecting and fixing them in place. This greatly helps to prevent damage to the capacitor element 4 by the flowing molding resin during molding.

[0062] In other words, as described above, the capacitor 1 of this embodiment is mounted on the circuit board by the base plate 6. However, when the capacitor 1 is molded together with the circuit board using molding resin, the capacitor 1 and the circuit board are housed in a molding fitting, and the molding resin is injected into the molding die under pressure.

[0063] At this time, the flowing mold resin flows into the opening 2 of the case 3, and a force is applied that pushes the sealing body 5, which is made of an elastic material, toward the capacitor element 4.

[0064] However, in this embodiment, a pressure receiving plate 12 is placed on the side of the sealing body 5 facing the opening 2 of the case 3, and this pressure receiving plate 12 is connected and fixed to the base plate 6. Therefore, even if the flowing mold resin tries to push the pressure receiving plate 12 during molding, the pressure receiving plate 12 is connected and fixed to the base plate 6, and the base plate 6 is in contact with the opening 2 of the case 3, so the pressure receiving plate 12 cannot be pushed toward the sealing body 5, and as a result, damage to the capacitor element 4 can be prevented.

[0065] In Figure 2, the small protrusions 20 provided at the four corners of the base plate 6 are intended to facilitate the upright mounting of the capacitor 1 on the circuit board, due to the bent shape of the connection terminal 9. [Explanation of Symbols]

[0066] 1 Capacitor 2 openings 3 cases 4 Capacitor elements 5 Sealing body 6 Seat board 7 Through hole 8 Through holes 9 Connection terminals 10 Aperture section 11 Bend section 12 Pressure receiving plate 13 Through hole 14 protrusions 15 groove 18 Daibu 19 Recess 20 small projections

Claims

1. The device comprises a cylindrical case with an opening at one end, a capacitor element housed within the case, a sealing body made of an elastic material mounted on the side of the case closer to the opening than the capacitor element, and a base plate positioned opposite the sealing body on the outside of the case on the opening side. The capacitor element has a connection terminal that penetrates the sealing body and extends to the base plate outside the opening. The outer periphery of the case, corresponding to the outer periphery of the sealing body, is provided with a constricted portion that narrows toward the outer periphery of the sealing body. In a capacitor in which a bent portion is provided at the end of the case on the opening side, the case is bent in the circumferential direction, A pressure receiving plate is placed on the opening side of the case of the sealing body. The outer periphery of the surface of the pressure receiving plate on the seat plate side is covered by the bent portion of the case when viewed from the opening side. A base portion is provided on the inner side of the portion covered by the bent portion on the seat plate side surface of the pressure receiving plate, projecting from the opening toward the seat plate. The aforementioned connection terminal is configured to extend through the base portion and outward from the opening, A capacitor in which the pressure receiving plate is made of a laser light absorbing material, the base plate is made of a laser light transmitting material, and the surface of the pressure receiving plate on the base side and the surface of the base plate on the pressure receiving plate side come into contact with each other, and the contact surfaces of the pressure receiving plate and the base plate are joined together as a single unit by laser welding.

2. On the side of the seat plate opposite to the pressure receiving plate, a recess is formed that is recessed toward the base portion. The capacitor according to claim 1, wherein the connecting portion between the pressure receiving plate and the seat plate is welded by a laser irradiated into the recess.

3. A capacitor mounting circuit board in which a capacitor according to claim 1 or 2 is mounted on the surface of a circuit board, and on the surface of the circuit board, at least the part of the capacitor closer to the circuit board than the constricted portion, and the base plate are covered with molded resin.

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