Capacitor holder and capacitor with capacitor holder

Abstract

To solve a problem in large-capacity capacitors in which, as digital transformation (EV) of mobile devices progresses, electronic boards with excellent vibration resistance are required, but the large-capacity capacitors have traditionally been inserted through holes, making it difficult to reduce the number of processes and costs.SOLUTION: A capacitor holder for securing a capacitor to an electronic board includes: a resin holder base; a through hole provided in the holder base; a lead wire groove formed from the through hole to the edge of the holder base; and a layered joint provided in a portion where the lead wire groove is not formed on the surface where the lead wire groove is formed, and which bonds with solder at a predetermined temperature, and can firmly secure a large-capacity capacitor to an electronic board by surface mounting.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a capacitor holder used for a type of capacitor that is connected via a through hole formed in an electronic substrate. [Background technology]

[0002] Capacitors are commonly used elements in electronic circuits, and will continue to be widely used in various fields as digitalization progresses. Although capacitors themselves are becoming smaller, when handling high frequencies or large currents, large-capacity capacitors are required, and relatively large-volume capacitors will continue to be used. When such capacitors are installed inside vehicles such as automobiles, they must be heat-resistant and vibration-resistant between them and the electronic boards on which they are mounted.

[0003] Such capacitors are firmly attached to the board by passing lead wires through through holes in the electronic board and then soldering them. However, because the lead wires on the capacitor element do not have much strength, there has been a demand for more firmly attached capacitors to the board.

[0004] Patent Document 1 provides a capacitor holder that meets these requirements. It is sometimes called a capacitor chip spacer or seat plate. The capacitor holder itself is cup-shaped, with a plate with metal rod-shaped legs inserted into a recess on the bottom, separate from the through-holes into which the capacitor lead wires are inserted.

[0005] The capacitor holder has its rod-shaped legs inserted into the through-holes in the electronic circuit board for fixing the holder, and then bent 90 degrees. The capacitor's lead wires are inserted into the through-holes for the lead wires, and then bent 90 degrees. After this, the capacitor is fixed with jet solder from the bottom side of the electronic circuit board. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-177348 Summary of the Invention [Problem to be solved by the invention]

[0007] The capacitor holder disclosed in Patent Document 1 can firmly secure a capacitor to an electronic board. However, it requires a process of inserting metal rod-shaped legs into the capacitor holder, and the capacitor must be inserted into the through-hole after the capacitor holder is inserted into the electronic board, so through-hole mounting must be performed in two stages. Furthermore, because jet soldering is performed from the backside of the electronic board, it must be performed in a separate process from other electronic components (such as chip resistors, chip capacitors, and LSIs) that are surface-mounted using a reflow oven. As a result, the component mounting process must be performed several times to manufacture one electronic board, which creates the problem of high costs. [Means for solving the problem]

[0008] The present invention has been conceived in view of the above-mentioned problems, and provides a capacitor holder that enables capacitors that have conventionally been mounted in through-holes on electronic boards to be surface-mounted using a chip mounter in the same way as chip components.

[0009] More specifically, the capacitor holder according to the present invention comprises: A capacitor holder for fixing an electronic board and a capacitor, a resin holder base material; a through hole provided in the holder base material; a lead wire groove formed from the through hole to an end of the holder base; The lead wire groove is provided on the surface where the lead wire groove is formed, in a portion where the lead wire groove is not formed, and is characterized by having a layered joint portion that joins with solder at a predetermined temperature.

[0010] Furthermore, a capacitor with a capacitor holder according to the present invention is characterized in that a lead wire is inserted into the through hole of the capacitor holder, and the lead wire is bent along the lead wire groove. [Effects of the Invention]

[0011] The capacitor holder according to the present invention uses solder paste to solder not only the lands on the electronic board to the capacitor leads, but also the layered joints to the lands, making it possible to form an electronic board in which the capacitors do not tilt or peel off even when subjected to strong vibrations.

[0012] This also eliminates the need to mount metal components other than capacitors in the capacitor holder using through-holes, and it also eliminates the need to provide through-holes for capacitor mounting in the electronic board, allowing for greater flexibility in constructing the electronic board as a multi-layer board.

[0013] In addition, like other chip components, they can be placed on electronic boards using a chip mounter (surface mount machine), making it possible to manufacture cheaper electronic boards in a shorter process time than before.

[0014] Furthermore, the chip components can be bonded to the electronic board together with other chip components in a single heating process in a reflow furnace, thereby shortening the process of mounting electronic component elements. [Brief explanation of the drawings]

[0015] [Figure 1] 1A and 1B are diagrams showing the appearance of a capacitor holder according to the present invention, in which (a) is a diagram of the capacitor holder and a capacitor to be inserted, and (b) shows the back surface of the capacitor holder and a capacitor 100 to be inserted. [Figure 2] 1A is a cross-sectional view of a through-hole of a capacitor holder, and FIG. 1B is a cross-sectional view showing the relationship between a lead wire groove, a lead wire, and a layered joint portion. [Figure 3] FIG. 10 is a cross-sectional view showing a case where there are two resin layers (a first resin layer and a second resin layer). [Figure 4] (a) The capacitor leads are inserted into the capacitor holder, and one lead is bent along the lead groove. (b) Both leads are bent. [Figure 5] 1A and 1B are side views showing how a capacitor with a capacitor holder is attached to an electronic circuit board, respectively. (a) is a view from the right side so that the front-rear direction can be clearly seen, and (b) is a view from the front so that the left-right direction can be clearly seen. [Figure 6] 1A and 1B are diagrams showing how the layered joint is bonded to the solder (solder paste) provided on the land, respectively. (a) A diagram showing the state where the capacitor with the capacitor holder is placed on the solder, and (b) A diagram showing the state where the layered joint is bonded to the solder. [Figure 7] 1A and 1B are diagrams illustrating a case where the layered joint has two layers, in which (a) the capacitor with the capacitor holder is placed on the solder, and (b) the layered joint is joined to the solder. [Figure 8] The results are from an example in which a first resin layer was applied to the material that will become the capacitor holder, and then a second resin layer was applied on top of that, and the contact angle was measured when a solder piece was melted. DETAILED DESCRIPTION OF THE INVENTION

[0016] The capacitor holder according to the present invention will be described below with reference to the drawings. Note that the following description exemplifies one embodiment of the present invention, and the present invention is not limited to the following description. The following description can be modified within the scope of the present invention.

[0017] Figure 1 shows the appearance of a capacitor holder 1 according to the present invention. Figure 1(a) shows the capacitor holder 1 and the capacitor 100 to be inserted. Figure 1(b) shows the back surface of the capacitor holder 1 and the capacitor 100 to be inserted. The side of the capacitor holder 1 where the capacitor 100 is inserted is called the front surface 10a, and the opposite side is called the back surface 10b. The back surface 10b is the surface that faces an electronic board (not shown) when the capacitor 100 attached to the capacitor holder 1 is mounted.

[0018] The capacitor 100 into which the capacitor holder 1 is inserted is a so-called radial type capacitor provided with lead wires 102. It may also be an axial type with lead wires extending from both ends of a cylinder. In this specification, the explanation will continue using a radial type capacitor 100 (height is 100h).

[0019] <Holder base material 10> [shape] The capacitor holder 1 is composed of a holder substrate 10. The holder substrate 10 is a plate-shaped member. A rectangular shape is considered suitable for easy processing, but other polygonal or circular shapes are also acceptable. The holder substrate 10 needs to be wider than the spacing 102w between the lead wires 102 when the capacitor 100 is fixed to the electronic board, and is desirably wider than the projected area of ​​the capacitor 100 projected from above when the capacitor 100 is fixed to the electronic board.

[0020] The holder substrate 10 may also be provided with a cup-shaped peripheral wall 20 on the surface 10a, with the surface 10a considered as the bottom. The peripheral wall 20 helps to hold the capacitor 100 when the capacitor holder 1 is inserted into the capacitor 100. In other words, since the peripheral wall 20 exists around the capacitor 100, it is possible to prevent the capacitor 100 from falling onto the electronic board due to vibration or the like.

[0021] A gap 20g where a wall surface has been removed may be provided in the peripheral wall 20. The gap 20g can be used to visually check the capacitance of the inserted capacitor 100 or to check whether the lead wires 102 of the capacitor 100 are sufficiently inserted into the capacitor holder 1. Furthermore, by applying an adhesive or a thermosetting resin to the inner surface of the peripheral wall 20, the adhesion between the capacitor 100 and the capacitor holder 1 can be made stronger.

[0022] The distance from the surface 10a to the edge of the peripheral wall 20 is called the peripheral wall height 20h. The peripheral wall height 20h is preferably set to be 10% to 50% of the height 100h of the capacitor 100. If the peripheral wall height 20h is too high, it becomes difficult to insert the capacitor holder 1 into the capacitor 100. Furthermore, if the peripheral wall height 20h is too high, the center of gravity of the capacitor holder 1 itself moves away from the electronic board, which increases the torque (rotational moment) when subjected to vibration, and increases the force that tries to peel the capacitor holder 1 off the electronic board.

[0023] 1(b), the back surface 10b of the holder substrate 10 is provided with through holes 12 for inserting the lead wires 102 of the capacitor 100, and lead wire grooves 14 that serve as guides when bending the lead wires 102 inserted from the front surface 10a. In addition, a layered joint 16 is provided in the area other than the lead wire grooves 14.

[0024] <Through holes formed in holder base material 10> The holder substrate 10 is provided with through holes 12 through which the lead wires 102 of the capacitors 100 to be mounted are inserted. Two through holes 12 are provided, spaced apart by the distance between the lead wires 102 when the capacitors 100 are mounted. FIG. 2(a) shows a cross section of the holder substrate 10 including the through holes 12. The capacitors 100 are mechanically inserted from the front surface 10a side of the holder substrate 10. Therefore, it is desirable that a taper 12e be formed on the edge of the through hole 12 on the front surface 10a side of the holder substrate 10.

[0025] <Lead Wire Groove of Holder Base Material 10> Referring again to Figure 1(b), a lead wire groove 14 is formed on the back surface 10b of the holder substrate 10 along a line connecting the through holes 12 to the end of the holder substrate 10. Figure 2(b) shows a cross section including the lead wire groove 14. The lead wire groove 14 is preferably used when it has a rectangular cross section with a depth 14d, but it may also be a groove with a V-shaped cross section.

[0026] It is desirable that the groove depth 14d of the lead wire groove 14 is at least shallower than the diameter 102φ of the lead wire 102. When the groove depth 14d is shallower than the diameter 102φ of the lead wire 102, a portion of the lead wire 102 protrudes from the back surface 10b, ensuring reliable bonding with the paste solder of the electronic substrate.

[0027] On the other hand, the amount by which the lead wire 102 protrudes from the back surface 10b is defined as the protrusion height 102r. If the protrusion height 102r is too high, there is a risk that the lead wire 102 may tilt to the left or right when the holder base material 10 and the electronic board are joined, which is not preferable. Therefore, it is desirable that the protrusion height 102r be smaller than the height 16h of the layered joint portion 16.

[0028] Furthermore, the lead wire grooves 14 are not provided between the through holes 12 of the holder base material 10. This is because if the lead wires 102 inserted into the through holes 12 become conductive with each other, the electronic circuit will short out.

[0029] The lead wire grooves 14 are formed up to the ends of the holder substrate 10. This is to provide an open space for excess solder paste to escape when the solder paste on the electronic substrate and the lead wires 102 are joined.

[0030] [Material] The capacitor 100 is fixed to the front surface 10a of the holder substrate 10. The back surface 10b is fixed to the surface of the electronic substrate. The holder substrate 10 is soldered to the electronic substrate via the layered joint 16. Therefore, the holder substrate 10 has temperature characteristics that prevent it from substantially deforming even at the melting temperature of the solder. Here, "not substantially deforming" means that it is permissible to deform to the extent that it does not cause any inconvenience when used as an electronic substrate even after being heated in a reflow furnace.

[0031] Suitable materials include synthetic resins such as polypropylene, nylon, polyethylene, POM, polycarbonate, acrylic, and PBT; heat-resistant resins such as polyphenylene sulfide, polyarylate, polysulfone, aromatic polyamide, aliphatic polyamide, polyamideimide, polyetherimide, polyethersulfone, polyetheretherketone, polybutylene terephthalate, and liquid crystal polymers (including liquid crystal polyester); thermosetting resins such as phenolic resin, epoxy resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, polyurethane epoxy resin, and phenolic resin; and materials obtained by filling these resins with glass fibers, etc. The peripheral wall 20 is formed of the same material as the holder base material 10, but other materials may also be used.

[0032] <Layered joint 16> The layered joint 16 is a layer in which fine particles with high wettability with solder are dispersed in a resin. The layered joint 16 is preferably provided on both sides of the lead wire groove 14. This is because by forming the land portion on the electronic board side where the solder paste is placed slightly larger, the lead wire 102 in the lead wire groove 14 is bonded to the land portion, and the layered joint 16 is also bonded to the land portion.

[0033] On the other hand, the layered joint 16 may be electrically connected to the lead wire 102, and since the layered joint 16 itself is electrically conductive, an arrangement in which the lead wires 102 are electrically connected to each other must be avoided.

[0034] Suitable metals that have high wettability with solder include Sn, Cu, Ag, Au, Ni, and Fe. The fine particles preferably have a maximum length of about 10 μm to 1 mm and are spherical, flake, needle, cigar, or other shapes.

[0035] The resin used has a softening point lower than the melting point of the solder. This is because the resin softens before the solder melts, making it easier for the dispersed metal particles to expose their tips (surface and interface). This temperature is called the "predetermined temperature." It can also be said to be the temperature at which soldering is performed to mount components on electronic boards. Specifically, thermoplastic elastomers (urethane, ester, amide, styrene, olefin, epoxy, PVC, polyester, etc.), low-density polyethylene, hot melt, etc. are suitable.

[0036] The layered joint 16 preferably contains metal particles in a proportion of 70 to 96 mass%, preferably 80 to 95 mass%, more preferably 85 to 95 mass%, and most preferably 87 to 93 mass%. If the metal particle content is higher than this, the amount of resin decreases, and adhesion to the electronic substrate decreases. Conversely, if the metal particle content is lower than this, the metal particles are not exposed during heating, and adhesion to the solder paste decreases.

[0037] 3 shows a layered joint 16 with a two-layer structure. In the layered joint 16 with a two-layer structure, the layer facing the back surface 10b of the holder substrate 10 is a first resin layer 16A, and the layer facing the first resin layer 16A is a second resin layer 16B. In other words, the first resin layer 16A is formed on the back surface 10b of the holder substrate 10, and the second resin layer 16B is layered on top of that. Here, the direction vertically away from the back surface 10b of the holder substrate 10 is referred to as "up."

[0038] The first resin layer 16A is preferably made of a resin that has excellent adhesiveness and adhesive strength with the holder substrate 10. The first resin layer 16A is also preferably made of a resin that does not substantially deform at the temperature in a reflow furnace. For example, a primer, a binder, or the like can be suitably used.

[0039] The second resin layer 16B is preferably made of a resin that has good adhesiveness to the first resin layer 16A and a softening point at a predetermined temperature. The same resins that can be used when the layered joint 16 described above is a single layer can be used.

[0040] <Joining structure> When the capacitor holder 1 of the present invention is used, no through-hole is required for mounting the capacitor 100 on the electronic board. Instead, the capacitor holder 1 of the present invention is attached to the capacitor 100 in advance. More specifically, the lead wires 102 of the capacitor 100 are inserted into the through-holes 12 provided in the capacitor holder 1 and folded into the lead wire grooves 14. This is called a capacitor 30 with a capacitor holder.

[0041] Figure 4 shows the process of making a capacitor with a capacitor holder 30. Referring to Figure 4(a), the lead wires 102 of the capacitor 100 are inserted into the through holes 12 of the capacitor holder 1 from the surface 10a of the capacitor holder 1 (see Figure 1(a)) (see also Figure 1(b)). Figure 4(a) shows the state in which one end of the inserted lead wire 102 is folded into the lead wire groove 14. Figure 4(b) shows the state in which the other lead wire 102 is also folded into the lead wire groove 14. In the state shown in Figure 4(b), the capacitor with a capacitor holder 30 is completed. Here, the direction along the lead wire groove 14 is defined as the front-to-rear direction, and the direction perpendicular to that is defined as the left-to-right direction.

[0042] The capacitor with capacitor holder 30 is placed on the land of an electronic board, just like other chip components. Figure 5 shows the state in which the capacitor with capacitor holder 30 is placed on the electronic board. Here, the electronic board is indicated by the reference numeral 200, the land by the reference numeral 202, and the solder paste by the reference numeral 204. Figure 5(a) is a view of the capacitor with capacitor holder 30 as seen from the right side, and Figure 5(b) is a view as seen from the front.

[0043] The capacitor 30 with the capacitor holder is placed with the layered joint portion 16 on the solder paste 204, and is heated in a reflow furnace to a temperature at which the solder paste 204 melts. The lead wires 102 of the capacitor 100 folded into the lead wire grooves 14 become wet with the melted solder paste 204, and the lands 202 and the lead wires 102 are joined.

[0044] The surface of the layered joint 16 facing the solder paste 204 is softened at the temperature of the reflow furnace, making it easier for the metal particles dispersed in the resin, which are easily wetted with solder, to come into contact with the solder paste 204. The metal particles that come into contact with the solder paste 204 become wet with the solder paste 204 and are thereby joined.

[0045] This bonded state is maintained even after the capacitor 30 with capacitor holder is removed from the reflow furnace. As a result, the lead wires 102 of the capacitor 30 are bonded to the lands 202 of the electronic substrate 200, and the surface of the layered bonded portion 16 of the capacitor holder 1 itself is bonded to the lands 202.

[0046] Figure 6 shows an enlarged view of the joint in Figure 5(b). Figure 6(a) shows the state in which the capacitor with capacitor holder 30 is placed on the solder paste 204. Figure 6(b) shows the state after passing through a reflow oven and the solder paste 204 has melted.

[0047] 7 shows a case where the layered joint 16 is composed of a first resin layer 16A and a second resin layer 16B. The first resin layer 16A is composed of a resin that firmly adheres to the holder substrate 10. The second resin layer 16B is composed of a resin in which metal particles that have strong adhesive strength to the first resin layer 16A and high wettability with solder are dispersed.

[0048] In the configuration of Figure 7, the solder paste 204 is bonded to the second resin layer 16B, and the first resin layer 16A ensures adhesion between the second resin layer 16B and the holder base material 10, so the combination of the layered joint 16 and the solder paste 204 can firmly bond the holder base material 10 and the land 202.

[0049] In this way, in the capacitor holder 1 according to the present invention, the lead wire 102 of the capacitor 100 is directly bonded to the land 202, and the capacitor holder 1 is also bonded to the land 202, so sufficient bonding strength can be obtained even if a through-hole for capacitor grounding is not provided in the electronic substrate 200. Furthermore, bonding between the lead wire 102 and the land 202 via the solder paste 204 and bonding between the layered bonding portion 16 and the land 202 are performed simultaneously, which makes it possible to omit a process. [Example]

[0050] A primer was applied to a thickness of 10 μm as a first resin layer 16A on an Amodel PPA resin substrate (a material that can be used for capacitor holders) manufactured by Solvay Specialty Polymers Japan, and then a conductive paint (SAP-60FL) manufactured by Sanwa Technique Co., Ltd. was applied on top of that to a thickness of 10 μm as a second resin layer 16B. The primer used was "Reclack 5000" manufactured by Fujikura Kasei Co., Ltd.

[0051] A 0.3 g solder piece was placed on the second resin layer 16B and heated to 300°C using air heating. After that, it was allowed to cool naturally, and the contact angle θ of the solder was measured. The results are shown in Figure 8. The average of three measurements was 22.7°. Furthermore, the solder piece was firmly bonded to the resin substrate. [Industrial Applicability]

[0052] The capacitor holder of the present invention allows radial capacitors, which previously required through-hole mounting, to be mounted using a chip mounter, and can also provide sufficient vibration resistance, making it suitable for use on a wide range of electronic boards mounted on mobile vehicles. [Explanation of symbols]

[0053] 1 Capacitor holder 10 Holder base material 10a (holder base material) surface 10b Back side (of holder base material) 12 (Holder base) through hole 12e Taper (of through hole) 14 Lead wire groove (in holder base) 14d (lead wire groove) depth 16 Layered joints 16h (layer joint) height 16A First Resin Layer 16B Second resin layer 20 (holder base) peripheral wall 20g (surrounding wall) gap 20h Wall height 30 Capacitor with Capacitor Holder 100 capacitors 100h height 102 lead wire 102w (lead wire) spacing 102φ (lead wire) diameter 102r (Lead wire) protrusion height 200 Electronic Boards 202 rand 204 Solder Paste

Claims

1. A capacitor holder for fixing an electronic board and a capacitor, a resin holder base material; a through hole provided in the holder base material; a lead wire groove formed from the through hole to an end of the holder base; The capacitor holder has a layered joint portion that is provided on the surface on which the lead wire grooves are formed, in a portion on which the lead wire grooves are not formed, and that is joined with solder at a predetermined temperature.

2. 2. The capacitor holder according to claim 1, wherein the layered joint portion has a resin layer in which a conductive metal is dispersed in a resin material that softens at the predetermined temperature.

3. The layered joint portion includes a first resin layer that adheres to the holder base material; 2. A capacitor holder according to claim 1, further comprising a second resin layer bonded to said first resin layer, said second resin layer being made of a resin material that softens at a temperature lower than said predetermined temperature and in which a conductive metal is dispersed.

4. 4. A capacitor holder according to claim 1, wherein a peripheral wall surrounding the periphery of the capacitor is provided on a surface of the holder substrate opposite to the surface on which the lead wire grooves are provided.

5. 2. A capacitor with a capacitor holder according to claim 1, wherein a lead wire is inserted into the through hole of the capacitor holder, and the lead wire is bent along the lead wire groove.

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