Printed wiring board and connection structure

Abstract

To provide a printed wiring board that has improved properties of solder when filled into a component insertion hole, in mounting a component such as a connector.SOLUTION: A printed wiring board has a component insertion hole. The component insertion hole has a pseudo square shape in top view, formed by connecting a plurality of arcs including arcs swelling to the outside at a corner part, and electroless / electrolytic plating is executed on the whole circumference of an inner wall of the component insertion hole.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a printed wiring board in which solder filling properties into component insertion holes are improved when components such as connectors are mounted on the printed wiring board, and to a connection structure between the printed wiring board and the components. [Background technology]

[0002] Conventionally, when mounting components such as connectors on a printed wiring board by automatic insertion, the connector is inserted into a component insertion hole in the printed wiring board and fixed by soldering. Recently, connectors have become smaller and have more pins, and there is a trend toward even higher density. As a result, component insertion holes for connectors, etc. on printed wiring boards are arranged in multiple rows and columns, which can result in holes that are not filled properly with solder during soldering.

[0003] 7 shows a state where a connector pin is inserted into a component insertion hole of a conventional printed wiring board. That is, the component insertion hole of the printed wiring board is processed by drilling to match the hole diameter, so that the shape is a circular through hole (through plated through hole). However, for example, when the leg of the connector is formed in a square shape, when a square corner pin 303 which is the leg of the connector is inserted into a circular component insertion hole 500 (through plated through hole) formed in the printed wiring board, there is inevitably a variation in the distance between the inner wall 302 of the through plated through hole and the leg of the connector between the square shape of the connector leg and the circular through plated through hole which is the component insertion hole of the printed wiring board, and this causes a problem that voids or the like are generated during solder mounting, and holes are not filled with solder properly.

[0004] Furthermore, when the legs of the connector are formed in a rectangular shape, as shown in FIG. 8, solder mounting is performed by inserting rectangular corner pins 403, which are the legs of the connector, into component insertion hole 600 formed in the shape of an elongated hole. However, since the distance between rectangular corner pins 403 and inner wall 402 of component insertion hole 600 varies depending on the location, and since the connector pins are arranged in multiple rows vertically and horizontally, voids and the like inevitably occur during solder mounting, resulting in areas not filled with solder.

[0005] Furthermore, when mounting components on a normal printed wiring board, the components are mounted on a sheet substrate consisting of multiple individual printed wiring boards attached to each other, making it difficult to fill all of the component insertion holes with solder without creating voids.

[0006] On the other hand, Patent Document 1 reports that, as a through hole (through-plated through hole) formed in a printed wiring board, a long hole is formed by connecting two or three circular holes of the same diameter with their centers offset in the same straight line to form a through hole. However, in Patent Document 1, six partial through holes are arranged in the connected long hole to increase the density of wiring when penetrating and connecting an insulating substrate. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 10-41601 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above-mentioned problems in the conventional art, and has as its object to provide a printed wiring board which improves the ability to fill solder into component insertion holes when mounting components such as connectors. [Means for solving the problem]

[0009] As a result of extensive research into solving the above problems, the inventor discovered that extremely good results could be obtained by making the shape of the component insertion hole a pseudo-rectangular shape made up of multiple connected circular arcs and applying electroless or electrolytic plating to the entire inner wall of the component insertion hole, and thus completed the present invention.

[0010] In other words, the present invention solves the above-mentioned problem by providing a printed wiring board having a component insertion hole, which, when viewed from above, has a pseudo-rectangular shape formed by connecting a plurality of arcs with arcs that bulge outward at the corners, and which is characterized in that electroless / electrolytic plating is applied to the entire inner wall of the component insertion hole. Effect of the Invention

[0011] According to the printed wiring board of the present invention, the component insertion hole for mounting components such as a connector has a pseudo-rectangular shape formed by connecting multiple arcs with arcs that bulge outward at the corners. Therefore, compared to conventional circular or long hole shapes, the distance between the inner wall of the component insertion hole and the legs of the connector can be made shorter, improving the solder filling properties during solder mounting. In addition, since the entire inner wall of the component insertion hole is plated with electroless or electrolytic plating, the solder filling is more stable and it is possible to prevent unfilled spaces (voids) with solder. [Brief description of the drawings]

[0012] [Figure 1] 1 is a plan view showing a component insertion hole according to a first embodiment of a printed wiring board of the present invention; [Diagram 2] FIG. 1 is a plan view of an individual printed wiring board having connector component insertion holes arranged in multiple rows and columns. [Diagram 3] FIG. 13 is a plan view of a sheet substrate on which a plurality of individual printed wiring boards each having connector component insertion holes arranged in multiple rows and columns are attached. [Figure 4] 5A to 5C are explanatory views showing an example of the order of drilling component insertion holes according to the first embodiment. [Diagram 5]FIG. 6 is a plan view showing a component insertion hole according to a second embodiment of a printed wiring board of the present invention; [Figure 6] 13A to 13C are explanatory views showing an example of the order of drilling component insertion holes according to the second embodiment. [Figure 7] FIG. 13 is a plan view of a circular component insertion hole according to a conventional technique; [Figure 8] FIG. 1 is a plan view showing a component insertion hole having an oblong shape according to a conventional technique; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] First, a first embodiment of a component insertion hole will be described with reference to FIG. Fig. 1 is a plan view of a component insertion hole 100 of a printed wiring board as viewed from above. As shown in Fig. 1, the component insertion hole 100 has a pseudo-square shape with arcs 101 that bulge outward at the corners. The component insertion hole 100 is formed by connecting eight arcs 101 that bulge outward, and has eight continuous connection parts of the arcs 101 on the outer periphery. Moreover, the entire periphery of the inner wall 102 of the component insertion hole 100 is subjected to electroless / electrolytic plating (not shown).

[0015] In this embodiment, as shown in Fig. 1, among the eight circular arcs 101, the arcs at the corners and the arcs other than the corners have different curvatures, and the arcs at the corners have a larger curvature than the arcs other than the corners. The multiple circular arcs that make up the component insertion hole may have the same curvature, but it is preferable in terms of ease of processing the component insertion hole to have the larger curvature of the arcs at the corners. The number of arcs constituting the pseudo-square component insertion hole is not limited to eight, but may be selected arbitrarily.

[0016] Further, in FIG. 1, a pseudo-square component insertion hole is shown as an example, but the shape of the component insertion hole is not limited to a square shape, and any quadrangular shape such as a rectangular shape described later can be selected.

[0017] Next, solder mounting of a component into the component insertion hole 100 will be described with reference to FIG. When mounting a component such as a connector on a printed wiring board, square pins 103, which are the legs of the connector, are inserted into component insertion holes 100 and fixed by solder mounting. By making the component insertion holes 100 shaped like a pseudo square, the distance between the inner wall of the component insertion hole and the legs of the connector can be shortened compared to the circular component insertion holes of the prior art (see FIG. 7), improving solder filling and preventing solder voids. For example, the solder area reduction rate of the component insertion hole 100 compared to the circular component insertion hole is 38.3%.

[0018] Fig. 2 shows an example in which component insertion holes 100 are formed in two vertical rows and 15 horizontal rows on an individual printed wiring board 200. As shown in Fig. 1, by making the shape of the component insertion holes 100 pseudo-square, the distance between the inner wall of the component insertion hole and the legs of the connector can be shortened, so that unfilled solder (voids) can be prevented even if the component insertion holes 100 for the square pins 103, which are the legs of the connector, are arranged in multiple vertical and horizontal rows.

[0019] Furthermore, when components are mounted on printed wiring boards in mass production, individual printed wiring boards 200 are soldered and mounted in the form of a sheet substrate 300 with multiple surfaces attached, as shown in FIG. 3 shows an example of a sheet substrate 300 on which four individual printed wiring boards 200 of the present invention are mounted. By forming the component insertion holes 100 for connectors or the like arranged on the sheet substrate 300 in a pseudo-square shape as shown in FIG. 1, it is possible to prevent the component insertion holes 100 from being left unfilled with solder during solder mounting even if the individual printed wiring boards 200 are mounted on multiple surfaces, by arranging a plurality of component insertion holes 104 vertically and horizontally on the individual printed wiring board 200. This makes it possible to provide a stable connection between the printed wiring board and components such as connectors.

[0020] Next, a processing example of the pseudo-square component insertion hole 100 will be described with reference to FIGS. 4(a), (b) and (c). In Fig. 4, the numbers 1 to 5 indicate the drilling order. For example, in Fig. 4(a), a φ0.55 mm drill is used to drill 1, 2, 3, 4 in a Z-shaped order, and then a φ1.0 mm drill is used to drill 5. When forming a pseudo-square corner portion, the pitch of the small diameter drill (φ0.55 mm) is set to be equal to or greater than the radius of the drill. By making the component insertion hole a pseudo-square shape similar to the shape of the square pin of the connector leg, the gap between the square pin and the inner wall of the component insertion hole can be made narrower than that of the circular component insertion hole of the conventional technology, which prevents the component insertion hole from being left unfilled with solder when mounting the component. In Figure 4(b), the process is performed in the order of 1, 2, 3, and 4 in a U shape. Other than that, it is the same as Figure 4(a). In Figure 4(c), the processing is performed in the X-shaped order of 1, 2, 3, and 4. The rest is the same as in Figure 4(a). As shown in Figure 4(a), (b), and (c), holes are drilled in the order of 1, 2, 3, and 4 using a φ0.55 mm drill, and then the inside of the arc of 1, 2, 3, and 4 is drilled with a φ1.0 mm drill as the 5th hole, and then electroless and electrolytic plating is applied to the entire inner wall of the component insertion hole. This makes the solder filling more stable and makes it possible to suppress the occurrence of voids.

[0021] As for the conditions for drilling holes, it is desirable to make the feed rate and chip load slower when drilling a pseudo-square hole than when drilling a circular hole, in consideration of concerns about bending of the drill. For example, the drill speed is 62 to 72 (krpm), the feed rate is 0.40 to 0.60 (m / min), the chip load is 6.5 to 8.5 (μm / rev), the entry board (backing board) is an aluminum plate, and the backup board (scrap board) is a phenolic resin laminate (Bakelite board) for drilling holes in printed wiring boards.

[0022] Next, a second embodiment of the component insertion hole will be described with reference to FIG. Fig. 5 is a plan view of a component insertion hole 400 of a printed wiring board as viewed from above. As shown in Fig. 5, the component insertion hole 400 has a pseudo-rectangular shape with arcs 201 that bulge outward at the corners. The component insertion hole 400 is formed by connecting 16 arcs 201 that bulge outward, and has 16 continuous connection portions of the arcs 201 on the outer periphery. Moreover, the entire periphery of the inner wall 202 of the component insertion hole 400 is subjected to electroless / electrolytic plating (not shown).

[0023] In this embodiment, as shown in Fig. 5, among the 16 circular arcs 201, the corner arcs and the non-corner arcs have different curvatures, and the corner arcs have a larger curvature than the non-corner arcs. The multiple circular arcs constituting the component insertion hole may have the same curvature, but it is preferable in terms of ease of processing the component insertion hole to have a larger curvature for the corner arcs. The number of arcs constituting the pseudo-rectangular component insertion hole is not limited to 16, but may be selected arbitrarily.

[0024] In Fig. 5, the legs of the connector are rectangular corner pins 203. When mounting a component such as a connector on a printed wiring board, rectangular corner pins 203, which are the legs of the connector, are inserted into component insertion hole 400 and fixed by solder mounting. By making the component insertion hole into a pseudo-rectangular shape, the distance between the inner wall of the component insertion hole and the legs of the connector can be shortened compared to the elongated component insertion hole of the prior art (see Fig. 8), preventing unfilled solder (voids). For example, the solder area reduction rate of component insertion hole 400 compared to the elongated component insertion hole (see Fig. 8) is 9.7%.

[0025] Next, a processing example of the pseudo-rectangular component insertion hole 400 will be described with reference to FIG. In Fig. 6, the numbers 1 to 9 indicate the order of drilling. For example, as shown in Fig. 6, the corners of the component insertion hole are drilled with a φ0.4 mm drill in the order of 1, 2, 3, and 4, and then drilled with a φ0.7 mm drill in the order of 5, 6, 7, 8, and 9. By making the component insertion hole into a pseudo-rectangular shape that is close to the shape of the rectangular pin of the connector leg, the gap between the rectangular pin and the inner wall of the component insertion hole 400 can be made narrower than that of the elongated hole-shaped component insertion hole of the conventional technology. This prevents the component insertion hole from being left unfilled with solder (voids) when mounting the component.

[0026] As for the conditions for drilling holes, it is desirable to make the feed rate and chip load slower when drilling a pseudo-rectangular hole than when drilling a long hole, in consideration of concerns about bending of the drill. For example, the drill speed is 62 to 72 (krpm), the feed rate is 0.40 to 0.60 (m / min), the chip load is 6.5 to 8.5 (μm / rev), the entry board (backing board) is an aluminum plate, and the backup board (scrap board) is a phenolic resin laminate (Bakelite board) for drilling holes in printed wiring boards. [Explanation of symbols]

[0027] 101, 201: Arc 102, 202, 302, 402: Inner wall 103, 203, 303, 403: Square pin 104: Multiple component insertion holes 100: Pseudo square part insertion hole 200: Individual printed wiring board 300: Sheet substrate (multiple individual printed wiring boards are surface-mounted) 400: Pseudo rectangular part insertion hole 500: Conventional circular part insertion hole 600: Conventional slot-shaped part insertion hole

Claims

1. A printed wiring board having a component insertion hole, the component insertion hole having a pseudo-rectangular shape, when viewed from above, formed by connecting a plurality of arcs having arcs that bulge outward at the corners, and the inner wall of the component insertion hole having an entire periphery coated with electroless or electrolytic plating.

2. 2. The printed wiring board according to claim 1, wherein the arcs at the corners of the component insertion hole and the arcs at other than the corners have different curvatures.

3. 2. The printed wiring board according to claim 1, wherein the pseudo quadrilateral shape is a pseudo square or rectangular shape.

4. 2. The printed wiring board according to claim 1, wherein the component insertion holes are arranged in a plurality of rows and columns on the printed wiring board.

5. 2. The printed wiring board according to claim 1, wherein components are mounted in the component insertion holes by a sheet substrate having a plurality of individual printed wiring boards attached thereto.

6. A printed wiring board according to any one of claims 1 to 5, a component inserted into the component insertion hole of the printed wiring board; A connection structure comprising:

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