Power conversion device

Abstract

The present invention realizes a printed circuit board and a power conversion device which are capable of preventing short circuit or insulation failure between fuse terminals after a fuse blowout due to overcurrent or the like at the time of an abnormality. A printed circuit board (10) comprises: a substrate (2) having a through-hole (3a); and a fuse (1) disposed on the substrate (2) so as to face the through-hole (3a) and attached by means of connection terminals (1b). The fuse (1) is provided so that a space (8) is formed at a distance from the substrate (2).

Description

Printed circuit board and power conversion device

[0001] The present application relates to a printed circuit board and a power conversion device.

[0002] Conventionally, in a printed circuit board on which a pattern fuse is provided together with a conductive pattern, a printed circuit board has been proposed in which an insulating hole is provided at a position to the side of the pattern fuse in a direction along the pattern fuse to prevent insulation failure after the pattern fuse is blown (see, for example, Patent Document 1).

[0003] When a pattern fuse blows, its constituent materials, copper foil or solder, vaporize or liquefy due to heat and scatter. These scattered materials may then adhere to the printed circuit board. If they adhere to adjacent patterns, the adjacent patterns may be short-circuited, resulting in poor insulation. Therefore, in the conventional printed circuit board disclosed in Patent Document 1, insulation holes are provided on the sides of the pattern fuse in a direction parallel to the pattern fuse to prevent poor insulation between adjacent patterns.

[0004] Japanese Patent Application Publication No. 7-30213

[0005] However, the conventional printed circuit board disclosed in the aforementioned Patent Document 1 has a problem in that, although it can prevent insulation defects between adjacent patterns, it cannot prevent short-circuiting or insulation defects between fuse terminals after the fuse blows. Therefore, if a pattern fuse is blown by a large current due to a circuit abnormality or the like and then the fuse terminals are short-circuited by a conductive foreign object or the like, the large current continues to flow. Furthermore, when the printed circuit board is mounted in, for example, a power conversion device, it also has a problem in that it cannot prevent short-circuiting or insulation defects between fuse terminals from foreign objects generated by components mounted in the power conversion device.

[0006] The present application discloses technology for solving the above-mentioned problems, and aims to provide a printed circuit board and a power conversion device that can prevent short circuits or poor insulation between fuse terminals after the fuse has blown due to an abnormal overcurrent or the like.

[0007] The present application discloses a printed circuit board including a substrate having a through hole, a fuse disposed on the substrate facing the through hole and attached via a connection terminal, the fuse being spaced apart from the substrate to form a space. The present application also discloses a power conversion device including the above-described printed circuit board, a cooler disposed above the printed circuit board and having a cooling water channel therein, and a shielding plate disposed between the printed circuit board and the cooler.

[0008] According to the printed circuit board and power conversion device disclosed in the present application, it is possible to obtain a printed circuit board and power conversion device that can prevent short circuits or poor insulation between fuse terminals after the fuse has blown due to an overcurrent or the like during an abnormality.

[0009] Fig. 1 is an enlarged perspective view showing a printed circuit board according to embodiment 1. Fig. 2 is an enlarged perspective view showing a printed circuit board according to embodiment 2. Fig. 3 is an enlarged perspective view showing a printed circuit board according to embodiment 3. Fig. 4 is an enlarged perspective view showing a printed circuit board according to embodiment 4. Fig. 5 is a schematic diagram showing a power conversion device according to embodiment 5.

[0010] A printed circuit board according to the first embodiment will be described below with reference to the drawings. Note that the same reference numerals in the various drawings indicate the same or equivalent parts.

[0011] Embodiment 1. Figure 1 is an enlarged perspective view of a printed circuit board according to embodiment 1. As shown in Figure 1, printed circuit board 10 of embodiment 1 includes substrate 2 having through hole 3a and fuse 1 disposed on substrate 2 opposite through hole 3a and attached via connection terminal 1b, with fuse 1 spaced apart from substrate 2. Wiring pattern 7 is provided on substrate 2, and connection terminal 1b of fuse 1 is connected to wiring pattern 7 of printed circuit board 10. Connection terminal 1b is formed, for example, of copper plated with tin, and wiring pattern 7 is formed, for example, of copper. Connection terminal 1b is formed to have a predetermined length so that main body 1a of fuse 1 does not come into contact with substrate 2. Printed circuit board 10 has space 8 between main body 1a of fuse 1 and substrate 2.

[0012] The fuse 1 mounted on the printed circuit board 10 according to the first embodiment is, for example, a glass tube fuse. The printed circuit board 10 to which the fuse 1 is attached is incorporated in a power conversion device 50 having, for example, a cooler 5, as described below. For example, a malfunction of the cooler 5 or an impact due to an accident could cause cooling water from the cooler 5 or conductive foreign matter such as a solder ball to flow to the position of the fuse 1 on the printed circuit board 10. For example, if the main body 1a of the fuse 1 is in contact with the substrate 2 of the printed circuit board 10, the main body 1a of the fuse 1 could become wet with cooling water, or conductive foreign matter such as a solder ball could become trapped between the main body 1a of the fuse 1 and the substrate 2. However, the fuse 1 mounted on the printed circuit board 10 according to the first embodiment has a sufficient space 8 between the main body 1a of the fuse 1 and the substrate 2 of the printed circuit board 10, thereby preventing short circuits or poor insulation between the connection terminals 1b of the fuse 1 due to cooling water from the cooler 5 or conductive foreign matter such as a solder ball.

[0013] Furthermore, the printed circuit board 10 of the first embodiment has through holes 3a between the connection terminals 1b of the fuse 1. The through holes 3a must be large enough to ensure an insulating distance between the connection terminals 1b. Specifically, the length of the width direction W of the through holes 3a preferably has an opening width greater than, for example, the width W1 of the wiring pattern 7. The through holes 3a are holes (holes) without a bottom, and are formed so as to ensure an insulating distance greater than that required when a line is drawn from a certain position on one wiring pattern 7 to various positions on the other wiring pattern 7.

[0014] With this configuration, even if cooling water or conductive foreign matter such as solder balls flows between the connection terminals 1b of the fuse 1, the foreign matter is excluded by the through holes 3a, thereby ensuring an insulating distance between the connection terminals 1b of the fuse 1. Also, as shown in Figure 1, by making the through holes 3a large enough to be circular, including perfect circles and ellipses, it is possible to ensure an insulating distance between the connection terminals 1b of the fuse 1. Furthermore, if a tool used to drill holes for screws or the like used to attach the substrate 2 of the printed circuit board 10 is used, a dedicated tool for forming the through holes 3a is not required, and the number of steps in the production of the printed circuit board 10 can be reduced.

[0015] As described above, printed circuit board 10 according to the first embodiment includes substrate 2 having through hole 3a, and fuse 1 disposed on substrate 2 opposite through hole 3a and attached via connection terminal 1b, with fuse 1 spaced apart from substrate 2 so as to form space 8 between fuse 1 and substrate 2. This makes it possible to prevent short-circuiting or poor insulation between connection terminals 1b of fuse 1 after the fuse has blown due to an overcurrent or other abnormality.

[0016] Embodiment 2. Figure 2 is an enlarged perspective view showing a printed circuit board according to embodiment 2. In Figure 2, components with the same reference numerals as those used to describe printed circuit board 10 in embodiment 1 indicate the same or corresponding configurations, and their description will be omitted. The printed circuit board 10 according to embodiment 2 differs from embodiment 1 in that the width of connection terminal 1b of fuse 1 is long in the width direction W and that the shape of through hole 3b is a polygon including a rectangle. In printed circuit board 10 according to embodiment 2, connection terminal 1b has a width that is approximately the same as width W2 of fuse 1, for example. Furthermore, connection terminal 1b has a predetermined height so that main body portion 1a of fuse 1 does not come into contact with substrate 2.

[0017] In particular, if the connection terminals 1b of the fuse 1 are long in the width direction W, but the distance between the connection terminals 1b or between the wiring patterns 7 is not that long, if the through holes are circular, a straight line connecting the ends of the opposing connection terminals 1b at the same position may not intersect with the through holes. On the other hand, even if the through holes are elliptical, the distance between the through holes at the ends of the connection terminals 1b is smaller than the center position, so it may not be possible to ensure a sufficient insulation distance.

[0018] In contrast, according to printed circuit board 10 of embodiment 2, as shown in Fig. 2, by making through holes 3b rectangular, the through holes 3b have the same width when viewed from any position on connection terminal 1b, thereby ensuring a sufficient insulation distance between connection terminals 1b of fuse 1. Note that in Fig. 2, the width of the rectangle of through holes 3b is set to, for example, approximately the same length as width W1 of wiring pattern 7 on board 2, but this does not necessarily have to be the same length as width W1 of wiring pattern 7 on board 2 as long as a sufficient insulation distance is ensured between connection terminals 1b of fuse 1. Also, the multiple cavities formed in connection terminal 1b shown in Fig. 2 are not necessarily required.

[0019] Embodiment 3. Figure 3 is an enlarged perspective view showing a printed circuit board according to embodiment 3. In Figure 3, components with the same reference numerals as those used to explain printed circuit board 10 in embodiments 1 and 2 indicate the same or corresponding configurations, and their description will be omitted. Printed circuit board 10 according to embodiment 3 differs from printed circuit board 10 according to embodiment 2 in that through hole 3c is formed by connecting a plurality of holes.

[0020] 3 , in printed circuit board 10 according to the third embodiment, through holes 3c are formed by continuously connecting a plurality of holes in the width direction W of connection terminals 1b of fuse 1. According to printed circuit board 10 according to the third embodiment, through holes 3c formed by connecting a plurality of holes can ensure an insulation distance between connection terminals 1b of fuse 1. Furthermore, by forming through holes 3c in this manner, there is no need to prepare dedicated tools according to the type of shape or size of through holes 3c, thereby reducing the number of processes during production of printed circuit board 10.

[0021] Furthermore, if a tool for drilling holes for screws or the like for mounting the printed circuit board 10 is used at this time, there is no need for a dedicated tool or a change of setup, which further reduces the number of steps in the production of the board 2 of the printed circuit board 10.

[0022] Embodiment 4. Figure 4 is an enlarged perspective view showing a printed circuit board according to embodiment 4. In Figure 4, components with the same reference numerals as those used to explain the printed circuit boards in embodiments 1 to 3 indicate the same or corresponding configurations, and their description will be omitted. As shown in Figure 4, in printed circuit board 10 according to embodiment 4, connection terminal 1b of fuse 1 is connected to wiring pattern 7 of substrate 2. Furthermore, connection terminal 1b has a predetermined height so that main body portion 1a of fuse 1 does not come into contact with substrate 2. Furthermore, printed circuit board 10 has space 8 between main body portion 1a of fuse 1 and substrate 2.

[0023] Furthermore, in printed circuit board 10 according to the fourth embodiment, this space 8 is filled with protective member 4 such as resin. Filling space 8 with protective member 4 prevents cooling water or conductive foreign matter such as solder balls from entering between connection terminals 1b of fuse 1, ensuring an insulation distance between connection terminals 1b of fuse 1 and preventing short circuits or poor insulation between fuse terminals.

[0024] Furthermore, the printed circuit board 10 according to the fourth embodiment is expected to have the effect of improving the earthquake resistance of the fuse 1. Although the printed circuit board 10 shown in Fig. 4 shows a state in which the entire space 8 between the connection terminals 1b of the fuse 1 is filled with the protective member 4, the same effect can be obtained by simply covering at least the connection terminals 1b on both ends with the protective member 4.

[0025] Fifth Embodiment. Fig. 5 is a schematic diagram showing a power conversion device according to a fifth embodiment. As shown in Fig. 5, a power conversion device 50 according to the fifth embodiment includes a printed circuit board 10 according to any one of the first to fourth embodiments, a cooler 5 disposed above the printed circuit board 10 and having a cooling water channel therein, and a shielding plate 6 disposed between the printed circuit board 10 and the cooler 5. The cooler 5 also includes a power semiconductor element 11, and terminals of the power semiconductor element 11 are physically and electrically connected by soldering to the printed circuit board 10 via holes (not shown) formed in the shielding plate 6. The power semiconductor element 11 is connected to electronic components (not shown) via wiring patterns 7 on the printed circuit board 10. The cooler 5 is provided with supports 9 for mounting the printed circuit board 10 and the shielding plate 6.

[0026] 5, the power converter 50 is provided with a cooler 5 having a cooling water channel therein to cool the power semiconductor elements 11. If the cooler 5 has a defect such as a blowhole or is broken due to a collision in a traffic accident, the cooling water may leak from the cooler 5. In the power converter 50 according to the fifth embodiment, by providing a shielding plate 6 between the cooler 5 and the printed circuit board 10, the amount of cooling water that gets on the printed circuit board 10 can be reduced, and the amount of cooling water that flows between the connection terminals 1b of the fuse 1 can be reduced.

[0027] As shown in Figure 5, if the width of the shielding plate 6 is made larger than the width of the printed circuit board 10 and the printed circuit board 10 can be covered with the shielding plate 6, the cooling water leaking from the cooler 5 will splash onto the shielding plate 6 and then fall off the edge of the shielding plate 6 on the outside of the printed circuit board 10, thereby significantly reducing the amount of cooling water flowing into the printed circuit board 10. Also, if the outer edge of the shielding plate 6 is machined, for example, diagonally downward, the cooling water will flow around the edge to the back (bottom) of the shielding plate 6, reducing the amount of cooling water dripping onto the printed circuit board 10. Also, if a hole is formed in the shielding plate 6 to electrically connect the power semiconductor element 11 and the printed circuit board 10, machining the edge around the hole in the shielding plate 6 diagonally upward can reduce the possibility of the cooling water on the shielding plate 6 dripping from the hole onto the printed circuit board 10.

[0028] In this way, by processing the edges of the shielding plate 6 in the areas where it would be problematic if cooling water were to drip onto the printed circuit board 10 facing upward, and the edges of areas on the outside of the printed circuit board 10 where it would not cause problems if cooling water were to drip onto the printed circuit board 10 facing downward, it is possible to properly deal with the cooling water without it dripping onto the printed circuit board 10. Furthermore, if cooling water does not get onto the printed circuit board 10, the circuit will not short-circuit due to the cooling water, and therefore the fuse 1 will not blow. Furthermore, by making the shielding plate 6 out of sheet metal, it is expected that it will also have the effect of blocking radiated noise.

[0029] Although various exemplary embodiments and examples are described in this application, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0030] REFERENCE SIGNS LIST 1 fuse, 1a main body, 1b connection terminal, 2 substrate, 3a, 3b, 3c through hole, 4 protective member, 5 cooler, 6 shielding plate, 7 wiring pattern, 8 space, 9 support, 10 printed circuit board, 11 power semiconductor element, 50 power conversion device, W width direction, W1, W2 width

Claims

1. A printed circuit board having a through-hole, and a fuse disposed opposite to the through-hole on the substrate and attached via a connection terminal, wherein the fuse is provided so that a space is formed at a distance from the substrate. A cooler disposed above the printed circuit board and having a cooling water channel inside. A power conversion device including a shielding plate disposed between the printed circuit board and the cooler.

2. The power conversion device according to claim 1, wherein the through-hole is circular or polygonal.

3. The power conversion device according to claim 1 or claim 2, wherein the through-hole has an opening width longer than the width of the wiring pattern on the substrate.

4. The power conversion device according to claim 1 or claim 2, wherein the through-hole is formed by connecting a plurality of holes.

5. The power conversion device according to claim 1 or claim 2, wherein the through-hole is formed by a tool used for the screw hole for mounting the substrate.

6. The power conversion device according to claim 1 or claim 2, wherein the connection terminal of the fuse is covered by a protection member.

7. The power conversion device according to claim 1 or claim 2, wherein the space between the fuse and the substrate is filled with a protection member.

8. The power conversion device according to claim 1 or claim 2, wherein the length in the width direction of the shielding plate is larger than the length in the width direction of the printed circuit board.

9. The cooler has a power semiconductor element. The power conversion device according to claim 1 or claim 2, wherein the terminals of the power semiconductor element are connected to the printed circuit board through holes formed in the shielding plate.