Surface mount capacitors, mounting plates for surface mounting, and electronic components

Abstract

To visually determine the quality of soldering to a circuit board in a surface-mounted capacitor formed by attaching a seat plate for surface-mounting to an aluminum electrolytic capacitor.SOLUTION: In a surface mount capacitor that includes a capacitor body, and a seat plate 100 attached to the sealing part side, and in which each lead terminal 5 of the capacitor body is inserted into a lead terminal insertion hole 111 of the seat plate 100, and that is soldered at the solder land formed on a circuit board in the state of being folded and stored in the lead terminal storage groove 111, a soldering auxiliary portion 400 made of a metal material and whose soldering state can be visually seen from the outside is arranged on the lower edge of the side surface of the seat plate so as to be adjacent to the end of the lead terminal storage groove.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a surface-mounted capacitor that enables surface mounting of an aluminum electrolytic capacitor on a circuit board and a seat plate for surface mounting thereof. More specifically, it relates to a technique that enables visual discrimination of the quality of soldering to a circuit board.

Background Art

[0002] In a lead-in-the-same-direction type (also called discrete type) aluminum electrolytic capacitor in which a pair of lead terminals are drawn out in the same direction from the sealing portion of a bottomed cylindrical exterior case in which a capacitor element is incorporated, in order to enable surface mounting on a circuit board, a synthetic resin seat plate having a pair of lead terminal insertion holes is attached to the sealing portion side of the exterior case, and the lead terminals drawn out to the bottom side of the seat plate through the lead terminal insertion holes are bent in a direction away from each other to form a surface-mounted (chip) type.

[0003] This type of chip capacitor is often soldered to a circuit board by the reflow soldering method. In particular, in an in-vehicle chip capacitor that requires particularly high vibration resistance, auxiliary terminals are provided on the bottom surface of the seat plate to increase the soldering strength (see, for example, Patent Documents 1 and 2).

[0004] As is well known, flux gas (gasified flux) is generated during soldering, and voids or cracks may occur when the flux gas remains in the fillet. This type of void or crack impairs the reliability of the solder connection.

[0005] In addition, due to the generated flux gas, the solder paste applied to the solder land portion is extruded outside the solder land portion, becomes spherical due to the heat during soldering, and solidifies as it is to form a solder ball, which may adhere to, for example, the solder mask (also called solder resist, etc.) of the circuit board or the seat plate of this product.

[0006] Furthermore, as an example unrelated to flux gas, during circuit board mounting, the solder paste applied to the solder pads can be compressed by the lead terminals, expanding its surface area. When the solder melts due to the heat during soldering, it may not be able to return completely to the solder pads, leaving behind solder balls outside the pads. This undesirable phenomenon can occur regardless of the presence or absence of auxiliary terminals.

[0007] Furthermore, with conventional chip-type capacitors, the auxiliary terminals are located on the bottom surface of the base plate, which presents a problem in that it is difficult to determine from the outside whether the soldering of the auxiliary terminals is good or bad after soldering. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2008-244033 [Patent Document 2] Japanese Patent Publication No. 2012-138414 [Overview of the project] [Problems that the invention aims to solve]

[0009] Therefore, the object of the present invention is to enable visual inspection of the quality of soldering to a circuit board in a surface-mount type capacitor, which is an aluminum electrolytic capacitor with a base plate for surface mounting attached. [Means for solving the problem]

[0010] To solve the above problems, the present invention includes several characteristic embodiments. First, the first embodiment includes a capacitor body in which a pair of lead terminals are drawn out in the same direction from the sealing portion of an outer case in which a capacitor element is built, and a synthetic resin base plate attached to the sealing portion side of the outer case. The base plate has a pair of lead terminal insertion holes through which the lead terminals are inserted, and the bottom surface of the base plate has lead terminal storage grooves that extend from each of the lead terminal insertion holes in opposite directions away from each other to the opposing sides of the base plate. In a surface-mount capacitor in which each of the above-mentioned lead terminals is inserted through the lead terminal insertion holes and bent to fit into the lead terminal storage grooves, and then soldered to a solder land portion formed on a circuit board, A soldering aid made of metal is positioned adjacent to the end of the lead terminal storage groove at the lower edge of the side surface of the above-mentioned seat plate, allowing the soldering state to be visually observed from the outside. 、 The above soldering assist part has an inclined surface formed from the side surface to the bottom surface of the base plate, The above-mentioned seat plate has a substantially annular retaining wall on its upper side into which the capacitor body is fitted, and the wall thickness of the portion of the retaining wall located above the inclined surface is TA, and the projected width of the inclined surface in plan view is TB, <TAである It is characterized by the following.

[0011] The second embodiment is characterized in that the metal material is provided on the inclined surface.

[0012] The third embodiment is characterized in that, in the second embodiment, the angle of the inclined surface with respect to the plane including the bottom surface is 45 to 80 degrees.

[0013] The fourth aspect is characterized in that, in the second or third aspect described above, the inclined surface is spatially in communication with the end of the lead terminal storage groove.

[0014] The fifth aspect is characterized in that, in any of the first to fourth aspects described above, the metal material is formed by vapor deposition, plating, or metal plate formation.

[0015] The sixth aspect is characterized in that, in any of the first to fifth aspects described above, the metal material used is iron, brass, nickel, titanium, copper, tin, or an alloy thereof.

[0016] The seventh aspect is characterized in that, in any of the first to sixth aspects, the inclined surface is roughened to improve the adhesion to the metal material.

[0017] The eighth aspect is characterized in that, in the fifth aspect, the metal plate is used for the metal material, and the metal plate is fixed to the inclined surface by an adhesive or embedding.

[0019] The tenth aspect is a synthetic resin seat plate that is mounted on the sealing portion side of the capacitor body from which a pair of lead terminals are drawn in the same direction from the sealing portion of the exterior case in which the capacitor element is incorporated, and the capacitor body is in a chip shape that can be surface-mounted. It has a pair of lead terminal insertion holes through which the lead terminals are inserted, and lead terminal storage grooves are formed on the bottom surface that extend to the opposing side surfaces in opposite directions away from each other from the respective lead terminal insertion holes. In the surface-mounting seat plate in which each lead terminal is inserted into the lead terminal insertion hole and soldered to the solder land portion formed on the circuit board in a state where their tip portions are housed in the lead terminal storage groove by bending, On the lower edge of the side surface of the seat plate, a soldering auxiliary portion having a metal material and visible from the outside in the soldering state is disposed adjacent to the end of the lead terminal storage groove. 、 The above soldering assist part has an inclined surface formed from the side surface to the bottom surface of the base plate, The above-mentioned seat plate has a substantially annular retaining wall on its upper side into which the capacitor body is fitted, and the wall thickness of the portion of the retaining wall located above the inclined surface is TA, and the projected width of the inclined surface in plan view is TB, <TAである It is characterized by this.

[0020] The eleventh aspect is characterized in that, in the tenth aspect, the metal material is provided on the inclined surface.

[0021] The twelfth aspect is characterized in that, in the eleventh aspect, the angle of the inclined surface with respect to the plane including the bottom surface is 45 to 80 degrees.

[0022] The 13th embodiment is characterized in that, in the 11th or 12th embodiment, the inclined surface is spatially in communication with the end of the lead terminal storage groove.

[0023] The 14th embodiment is characterized in that, in any of the 10th to 13th embodiments, the metal material is formed by vapor deposition, plating, or metal plate.

[0024] The 15th embodiment is characterized in that, in any of the 10th to 14th embodiments above, the metal material used is iron, brass, nickel, titanium, copper, tin, or an alloy thereof.

[0025] The sixteenth embodiment is characterized in that, in any of the eleventh to fourteenth embodiments, the inclined surface is roughened to improve adhesion with the metal material.

[0026] The 17th embodiment is characterized in that, in the 14th embodiment, the metal plate is used for the metal material, and the metal plate is fixed to the inclined surface by adhesive or embedding.

[0028] The present invention has a 19th aspect, which includes the first to 8th This also includes electronic components in which the soldering aid portion in any embodiment of a surface-mount capacitor is soldered together with the lead terminals to a solder land portion of a circuit board. [Effects of the Invention]

[0029] According to the present invention, in a surface-mount type capacitor in which a base plate for surface mounting is attached to an aluminum electrolytic capacitor, the quality of the soldering to the circuit board can be visually determined. [Brief explanation of the drawing]

[0030] [Figure 1] A front view showing a surface-mount capacitor according to the present invention, separated into a capacitor body and a mounting plate for surface mounting, with each part shown as a cross-section. [Figure 2] A perspective view of the surface mount mounting base plate shown above, seen from the top. [Figure 3a] A perspective view of the surface mount mounting base plate shown above, seen from the bottom. [Figure 3b] A perspective view showing a modified example of the soldering aid shown in Figure 3a. [Figure 4] This is a cross-sectional view showing a magnified view of the soldering support portion of the seat plate shown above. [Figure 5a] The above soldering support section is shown as a perspective view from the bottom. [Figure 5b] A perspective view showing a modified example of the soldering aid shown in Figure 5a. [Modes for carrying out the invention]

[0031] Next, several embodiments of the present invention will be described with reference to Figures 1 to 5, but the present invention is not limited to these embodiments.

[0032] First, referring to Figure 1, the surface-mount capacitor according to the present invention comprises an aluminum electrolytic capacitor (hereinafter sometimes referred to as the "capacitor body") 1 and a base plate (hereinafter sometimes simply referred to as the "base plate") 100 for surface mounting.

[0033] The capacitor body 1 is a lead-unidirectional type (also called discrete type) in which a pair of lead terminals 5a and 5b are drawn out in the same direction from the sealing portion 4 of the outer case 3 in which the capacitor element 2 is built.

[0034] The outer casing 3 may be a bottomed cylindrical shape made of aluminum, and its opening is closed by a rubber seal 6 as the sealing portion 4. The rubber seal 6 is preferably made of butyl rubber. To improve the airtightness of the sealing portion 4, transverse rib grooves 7 are formed in the circumferential direction along the rubber seal 6 on the outer surface of the outer casing 3.

[0035] In this example, one lead terminal 5a is the cathode side and the other lead terminal 5b is the anode side, both of which are extended to the outside through the rubber seal 6. When there is no need to distinguish between lead terminals 5a and 5b, they are collectively referred to as lead terminal 5.

[0036] The lead terminal 5 is originally a round wire, but after passing through the rubber seal 6 and being pulled out to the outside, it is processed into a flat strip shape in a pressing process.

[0037] Referring to Figure 2, the base plate 100 is a square (modified hexagon) with two adjacent corners 100c and 100d cut off at an angle, and the entire structure is made of heat-resistant synthetic resin. The two adjacent corners 100c and 100d of the base plate 100 are cut off at an angle to facilitate polarity determination. In this embodiment, the corners 100c and 100d that are cut off at an angle indicate the anode side.

[0038] On the upper surface 100a of the base plate 100, which is the component mounting surface, a circular recess is formed into which the sealing portion 4 of the capacitor body 1 is fitted. In addition, a retaining wall 300 surrounding the sealing portion 4 of the capacitor body 1 is provided on the upper surface 100a of the base plate 100.

[0039] In this embodiment, the retaining wall 300 is formed as base portions 311 erected at the four corners of the base plate 100 so as to be in contact with the sealing portion 4 of the capacitor body 1. In this case, for polarity determination, of the four base portions 311a to 311d, the cathode-side base portions 311a and 311b are made taller than the anode-side base portions 311c and 311d. Conversely, the anode-side base portions 311c and 311d may be made taller than the cathode-side base portions 311a and 311b.

[0040] The base plate 100 is provided with a pair of lead terminal insertion holes 111a and 111b through which lead terminals 5a and 5b are inserted. When there is no need to distinguish between lead terminal insertion holes 111a and 111b, they are collectively referred to as lead terminal insertion hole 111.

[0041] As shown in Figure 3, lead terminal storage grooves 112a and 112b are formed on the bottom surface 110b of the base plate 100, extending from each lead terminal insertion hole 111a and 111b in opposite directions away from each other to the opposing side surfaces 113a and 113b of the base plate 100. In addition, disc-shaped spacers 114 are formed at the four corners of the bottom surface 110b of the base plate 100 to maintain the base plate 100 at a predetermined height from the circuit board when mounted on a circuit board (not shown).

[0042] The lead terminal storage grooves 112a and 112b are collectively referred to as lead terminal storage groove 112 when there is no need to distinguish between them. Similarly, the opposing sides 113a and 113b are collectively referred to as side 113 when there is no need to distinguish between them. The base plate 100 has two other opposing sides in addition to sides 113a and 113b, but in this embodiment, the other two opposing sides are not processed in any way.

[0043] By inserting the lead terminals 5a and 5b into the lead terminal insertion holes 111a and 111b, and then placing the capacitor body 1 on the upper surface (component mounting surface) 100a of the base plate 100, the lead terminals 5a and 5b are bent in opposite directions away from each other and stored in the lead terminal storage grooves 112a and 112b, thereby creating a surface-mount type capacitor 1A that can be surface-mounted on a circuit board.

[0044] Surface mount type capacitor 1A is typically mounted to a circuit board (not shown) by reflow soldering. Specifically, solder paste is applied to the solder pads formed on the circuit board, the lead terminals 5a and 5b of the surface mount type capacitor 1A are placed on top of it, and then the capacitor is heated in a heating oven to melt the solder paste and solder it in place.

[0045] However, since the lead terminals 5a and 5b are located on the bottom surface 100b of the base plate 100, it is difficult to visually inspect from the outside whether the soldering has been done properly.

[0046] Referring to Figures 3 to 5, in this invention, a soldering aid section 400 is provided adjacent to the end of the lead terminal storage groove 112, allowing the soldering state to be visually observed from the outside.

[0047] In this embodiment, as shown in Figure 3a, the soldering assist portion 400 is provided in a total of four locations: two on the left and right sides of the end of one lead terminal storage groove 112a on the side surface 113a side, and two on the left and right sides of the end of the other lead terminal storage groove 112b on the side surface 113b side.

[0048] These soldering support parts 400 may have the same configuration, but the configuration of the soldering support parts 400 may be individually changed depending on, for example, the shape of the solder land portion on the circuit board side. Also, as shown in Figure 3b, the soldering support part 400 may be formed over the entire width of the lower edge of the side surface 113 of the base plate 100.

[0049] The soldering assist portion 400 is provided on the lower edge of the side surface 113 of the seat plate 100, and preferably includes an inclined surface 410 formed from the side surface 113 to the bottom surface 100b of the seat plate 100. In the embodiment shown in Figure 5a, the inclined surface 410 is formed from the middle portion of the side surface 113 of the seat plate 100 to the bottom surface 110b, but as shown in Figure 5b, it may be formed from the upper edge of the side surface 113 of the seat plate 100 to the bottom surface 110b.

[0050] Furthermore, as shown in Figures 5a and 5b, the inclined surface 410 is preferably spatially in communication with the end of the lead terminal storage groove 112, but it may also be formed at a distance from the lead terminal storage groove 112.

[0051] A solderable metal material 420 is provided on the inclined surface 410. The metal material 420 may be formed by vapor deposition, plating, or metal plate formation. In a preferred embodiment, the metal material 420 may be iron, brass, nickel, titanium, copper, tin, or an alloy thereof.

[0052] When a metal plate is used as the metal material 420, the metal plate is fixed to the inclined surface 410 by an adhesive or embedding. However, including the cases of vapor deposition and plating, the inclined surface 410 is preferably roughened to improve the adhesion with the metal material 420.

[0053] Also, the angle of the inclined surface 410 with respect to the plane including the bottom surface 100b of the seat plate 100 is preferably 45 to 80 degrees. By providing this inclined surface 410, the strength of the seat plate 100 is reduced accordingly. For example, when the capacitor body 1 is mounted, there is a risk of cracking or chipping of the seat plate 100.

[0054] To prevent this, in this embodiment, the following measures are taken. As described above, the seat plate 100 is provided with a substantially annular holding wall 300 on the upper surface 100a side where the capacitor body 1 is fitted.

[0055] Referring to FIG. 4, the wall thickness of the wall portion (pedestal portion 311 in this embodiment) located above the inclined surface 410 of this holding wall 300 is designated as TA, and the projected width of the inclined surface 410 in a plan view is designated as TB. By setting TB < TA, for example, when the capacitor body 1 is mounted, cracking or chipping of the seat plate 100 is prevented.

[0056] According to the present invention, since the soldering auxiliary portion 400 having the metal material 420 is arranged adjacent to the end of the lead terminal storage groove 112 at the lower end edge of the side surface 113 of the seat plate 100 and the soldering state from the outside is visible, for example, during reflow soldering, the quality of soldering can be determined by the state of solder attachment to the soldering auxiliary portion 400. In addition, since the soldering auxiliary portion 400 is soldered to the solder land portion of the circuit board, the soldering strength is increased accordingly.

[0057] As described above, the present invention has been described using embodiments, but the technical scope of the present invention is not limited to the description of the above embodiments. Any changes or improvements added to the above embodiments by those skilled in the art are also included in the technical scope of the present invention. [Explanation of Symbols]

[0058] 1 Capacitor body 1A surface mount capacitor 2 Capacitor elements 3. Outer case 4 Sealing part 5(5a,5b) Lead terminals 6. Rubber seal body 7. Horizontal groove 100 seat board 100a Top surface of the seat plate (parts placement surface) 100b Bottom surface of the seat board 111 (111a, 111b) Lead terminal insertion hole 112 (112a, 112b) Lead terminal storage groove 113(113a,113b) Side 114 Spacer 300 Holding part 311 (311a~311d) Base 400 Soldering Aid Unit 410 Slope 420 Metal materials

Claims

1. The capacitor body includes a capacitor element housed in an outer casing with a pair of lead terminals extending in the same direction from the sealing portion, and a synthetic resin base plate attached to the sealing portion side of the outer casing. The base plate has a pair of lead terminal insertion holes through which the lead terminals are inserted, and the bottom surface of the base plate has lead terminal storage grooves that extend from each of the lead terminal insertion holes in opposite directions away from each other to the opposing sides of the base plate. In a surface-mount capacitor in which each of the above-mentioned lead terminals is inserted through the lead terminal insertion holes and bent to fit into the lead terminal storage grooves, and then soldered to a solder land portion formed on a circuit board, A soldering aid made of metal is positioned adjacent to the end of the lead terminal storage groove at the lower edge of the side surface of the above-mentioned seat plate, allowing the soldering state to be visually observed from the outside. The above soldering assist part has an inclined surface formed from the side surface to the bottom surface of the base plate, The base plate has a substantially annular retaining wall on its upper side into which the capacitor body is fitted, and the wall thickness of the portion of the retaining wall located above the inclined surface is TA, and the projected width of the inclined surface in a plan view is TB, wherein TB < TA.

2. The surface-mount capacitor according to claim 1, characterized in that the above-mentioned metal material is provided on the above-mentioned inclined surface.

3. The surface-mount capacitor according to claim 1 or 2, characterized in that the angle of the inclined surface with respect to the plane including the bottom surface is 45 to 80 degrees.

4. The surface-mount capacitor according to any one of claims 1 to 3, characterized in that the above-mentioned inclined surface is spatially in communication with the end of the lead terminal housing groove.

5. The surface-mount capacitor according to any one of claims 1 to 4, characterized in that the above metal material is formed by vapor deposition, plating, or a metal plate.

6. The surface-mount capacitor according to any one of claims 1 to 5, characterized in that the above metal material is iron, brass, nickel, titanium, copper, tin, or an alloy thereof.

7. The surface-mount capacitor according to any one of claims 1 to 6, characterized in that the above-mentioned inclined surface is roughened in order to improve adhesion with the above-mentioned metal material.

8. The surface-mount capacitor according to claim 5, characterized in that the above metal plate is used on the above metal material, and the above metal plate is fixed to the inclined surface by adhesive or embedding.

9. A base plate made of synthetic resin that is attached to the sealing portion side of a capacitor body from which a pair of lead terminals are drawn out in the same direction, and which makes the capacitor body a surface-mountable chip type, wherein the capacitor body is attached to the sealing portion side of the outer casing from which a capacitor element is built-in, It has a pair of lead terminal insertion holes through which the lead terminals are inserted, and the bottom surface has lead terminal storage grooves that extend from each of the lead terminal insertion holes to the opposing sides in opposite directions, away from each other. In a surface-mount mounting base plate in which each of the above-mentioned lead terminals is inserted through the lead terminal insertion hole and its tip portion is housed in the lead terminal storage groove by bending, the base plate is soldered to a solder land portion formed on a circuit board, A soldering aid made of metal is positioned adjacent to the end of the lead terminal storage groove at the lower edge of the side surface of the above-mentioned seat plate, allowing the soldering state to be visually observed from the outside. The above soldering assist part has an inclined surface formed from the side surface to the bottom surface of the base plate, The above-mentioned base plate has a substantially annular retaining wall on its upper side into which the capacitor body is fitted, and the wall thickness of the portion of the retaining wall located above the inclined surface is TA, and the projected width of the inclined surface in a plan view is TB, wherein TB < TA.

10. The surface mounting base plate according to claim 9, characterized in that the soldering assist portion has an inclined surface formed from the side surface to the bottom surface of the base plate, and the metal material is provided on the inclined surface.

11. The base plate for surface mounting according to claim 9 or 10, characterized in that the angle of the inclined surface with respect to the plane including the bottom surface is 45 to 80 degrees.

12. The base plate for surface mounting according to any one of claims 9 to 11, characterized in that the inclined surface is spatially in communication with the end of the lead terminal storage groove.

13. The base plate for surface mounting according to any one of claims 9 to 12, characterized in that the metal material is formed by vapor deposition, plating, or metal plate.

14. The base plate for surface mounting according to any one of claims 9 to 13, characterized in that the metal material used is iron, brass, nickel, titanium, copper, tin, or an alloy thereof.

15. The base plate for surface mounting according to any one of claims 9 to 14, characterized in that the inclined surface is roughened to improve adhesion with the metal material.

16. The base plate for surface mounting according to claim 13, characterized in that the metal plate is used on the metal material, and the metal plate is fixed to the inclined surface by adhesive or embedding.

17. An electronic component in which the soldering aid portion of a surface-mount capacitor according to any one of claims 1 to 8 is soldered together with the lead terminal to a solder land portion of a circuit board.

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