Capacitor

Abstract

To provide a capacitor which can ensure insulation between an electrode surface of a capacitor element and a bus bar, and also allows positioning and lifting prevention of the capacitor element, without using a separate insulation member.SOLUTION: A capacitor comprises: a case 5; a capacitor element 2 which has a first electrode surface 21 facing a case opening part 53 side and a second electrode surface 22 facing a case bottom part 51 side; a first bus bar 3 connected to the first electrode surface 21; a second bus bar 4 connected to the second electrode surface 22; and filling 6. The case 5 has a protrusion 54 which extends from the bottom part 51 and a lateral wall part 52 so as to define a gap G between itself and an inner surface of the lateral wall part 52. The second bus bar 4 has an erect surface part 41b which extends along a lateral surface 24 of the capacitor element 2 to the opening part 53 side of the case 5. With the erect surface part 41b inserted into the gap G between the protrusion 54 and the lateral wall part 52, the protrusion 54 is interposed between the first electrode surface 21 and the erect surface part 41b.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This invention relates to a capacitor in which a capacitor element is housed in a case and filled with a filler.

Background Art

[0002] In Patent Document 1, a capacitor includes a capacitor element, a first terminal connected to the first electrode of the capacitor element, a second terminal connected to the second electrode, a capacitor case that houses the capacitor element and the first and second terminals, a resin filled in the capacitor case, and an insulating plate. In the capacitor, the first electrode of the capacitor element is oriented upward and the second electrode is oriented downward, and the second terminal connected to the second electrode is extended upward along the side surface of the capacitor element and drawn out of the case. By drawing out, an insulating plate is interposed between the first electrode and the second terminal that are close to each other. When interposing, the protrusion of the insulating plate is fitted into the hole of the second terminal to fix the second terminal to the insulating plate, and the insulating plate is inserted into and fixed to the fixing portion provided on the inner surface of the capacitor case.

[0003] In the capacitor of Patent Document 1, since the capacitor element is fixed to the capacitor case via the second terminal and the insulating plate, it is considered that the floating of the capacitor element during resin filling can be suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the capacitor of Patent Document 1 has a separate insulating plate, there are problems such as an increase in cost and an increase in the number of assembly steps.

[0006] The present invention aims to provide a capacitor that can achieve insulation between the electrode surface of the capacitor element and the busbar, position the capacitor element, and prevent the capacitor element from floating up, without using a separate insulating member. [Means for solving the problem]

[0007] The capacitor of the present invention comprises a case 5 having a bottom portion 51, a side wall portion 52, and an opening 53; a capacitor element 2 housed in the case 5 with a first electrode surface 21 facing the opening 53 side of the case 5 and a second electrode surface 22 facing the bottom portion 51 side of the case 5; a first bus bar 3 connected to the first electrode surface 21; a second bus bar 4 connected to the second electrode surface 22; and a filler 6 filled inside the case 5. The case 5 further has a projection 54 extending from the bottom portion 51 and / or the side wall portion 52 to form a gap G between itself and the inner surface of the side wall portion 52. The second bus bar 4 has a vertical portion 41b extending along the side surface 24 of the capacitor element 2 toward the opening 53 side of the case 5, and the vertical portion 41b is inserted into the gap G between the projection 54 and the side wall portion 52, so that the projection 54 is interposed between the first electrode surface 21 and the vertical portion 41b.

[0008] In the above capacitor, it is preferable to have a protruding portion 52b that extends outwards toward the inside of the case 5, thereby creating the gap G. [Effects of the Invention]

[0009] The capacitor of the present invention has a case with a projection that forms a gap between it and the side wall, and since the projection is interposed between the first electrode surface and the vertical surface, insulation between the first electrode surface and the vertical surface can be ensured without using a separate insulating member. Furthermore, since the vertical surface is inserted into the gap between the projection and the side wall, the capacitor element can be positioned via the second busbar. In addition, the capacitor element can be prevented from floating up.

[0010] Furthermore, if the case has a protruding section that extends inward from the gap, the required resin thickness for the capacitor element (the distance from the capacitor element to the outer surface of the side wall) can be secured simply by inserting the vertical section into the gap. [Brief explanation of the drawing]

[0011] [Figure 1] This is an exploded perspective view showing a capacitor according to one embodiment of the present invention. [Figure 2] This is a magnified perspective view of the area near the protrusion. [Figure 3] This is a cross-sectional view showing the process of inserting the vertical section into the gap. [Figure 4] This is a perspective view of a capacitor. [Figure 5] This is a perspective view showing variations of through holes and notches. [Figure 6] This is a front view showing a modified example of the protrusion. [Figure 7] This is a cross-sectional view showing a modified example of the protrusion. [Modes for carrying out the invention]

[0012] Next, an embodiment of the capacitor of this invention will be described in detail with reference to the drawings. As shown in Figures 1 and 4, the capacitor 1 of this invention comprises a capacitor element 2, a first busbar 3, a second busbar 4, a case 5 housing these, and a filler material 6 filled inside the case 5. The above components will be described below, but the concept of "up and down" refers to the time of manufacturing, more specifically when filling the filler material 6, and does not necessarily define the up and down during use.

[0013] The capacitor element 2 is a film capacitor formed by winding a metallized film, which is made by depositing metal onto an insulating film, as shown in Figure 1. A first electrode surface 21 is provided on one end face in the axial direction, and a second electrode surface 22 is provided on the other end face. These electrode surfaces are formed, for example, by thermal spraying metal. When viewed from the axial direction, the capacitor element 2 has a barrel shape with approximately semicircular bulges 23 at both ends, or more specifically, a rectangular shape with rounded corners (R) provided at the four corners. It has a side surface 24 between the first electrode surface 21 and the second electrode surface 22 (the surrounding surface) consisting of a flat portion 24a and a curved portion 24b. Multiple capacitor elements 2 are arranged side by side, specifically four, with the first electrode surface 21 facing upwards and the second electrode surface 22 facing downwards, and with the flat portions 24a facing each other, to form a group of capacitor elements. Note that the capacitor element 2 is not limited to a film capacitor; various capacitor elements such as electrolytic capacitors and ceramic capacitors may be used. Various shapes can be used, such as cylindrical or prismatic shapes. The number of pieces can also be changed as needed.

[0014] The first busbar 3 is formed by cutting a conductive metal plate such as aluminum or copper into a predetermined shape and bending it as appropriate, and includes a first substrate portion 31 that overlaps with (contacts) the first electrode surface 21, and a first external connection portion 32 that extends from the first substrate portion 31 and is used for connecting to external equipment (not shown).

[0015] As shown in Figure 1, the first substrate portion 31 comprises a first planar portion 31a that is approximately rectangular in plan view, and a rising portion 31b that extends upward from one of the long sides of the first planar portion 31a, and its cross-section is approximately L-shaped. The first planar portion 31a is oriented longitudinally in the direction in which the capacitor elements 2 are arranged side by side, and overlaps with the first electrode surfaces 21 of all the capacitor elements 2. Of the two long sides of the first planar portion 31a, the long side on the side without the rising portion 31b is provided with a tongue-shaped connecting piece 33 for connecting to the first electrode surface 21.

[0016] The first external connection part 32 is provided so as to extend in the lateral direction from the upper end of the rising part 31b and in a direction opposite to the first flat part 31a in plan view.

[0017] The second bus bar 4 is formed by cutting out a conductive metal plate such as aluminum or copper into a predetermined shape and appropriately bending it, and includes a second substrate part 41 that overlaps (contacts) the second electrode surface 22, and a second external connection part 42 that extends from the second substrate part 41 and is used for connection to an external device not shown.

[0018] As shown in FIG. 1, the second substrate part 41 includes a second flat part 41a having a substantially rectangular shape in plan view and a standing part 41b that extends upward from one long side of the second flat part 41a, and its cross section is substantially L-shaped. The second flat part 41a has its longitudinal direction oriented in the parallel arrangement direction of the capacitor elements 2 and overlaps the second electrode surfaces 22 of all the capacitor elements 2. A tongue-shaped connection piece 43 for connection to the second electrode surface 22 is provided on the long side of the second flat part 41a on the side where the standing part 41b is not provided among the two long sides.

[0019] The standing part 41b is arranged along the side surface 24 of the capacitor element 2. The lateral width is the same as that of the second flat part 41a. The vertical length is made larger than the axial length of the capacitor element 2 (see FIG. 3). A through hole 44 for inserting a protrusion 54 of a case 5 described later is provided in this standing part 41b.

[0020] A plurality (four in FIG. 1) of through holes 44 are provided. Specifically, the number of through holes 44 provided is the same as the number of capacitor elements 2 adjacent to the standing surface portion 41b. However, it is not necessarily required to match the number of capacitor elements 2. For example, as shown in FIGS. 5B and 5C, one through hole 44 having a width through which a plurality of protrusions 54 can be inserted may be provided. Further, the through hole 44 is provided at a position in a plan view where the bulging portion 23 of the capacitor element 2 is adjacent, that is, at a position where the capacitor element 2 is closest to the standing surface portion 41b. This through hole 44 is provided so as to straddle the second flat portion 41a. However, as shown in FIG. 5C, it may be provided only on the standing surface portion 41b, or as shown in FIGS. 5A and 5B, it may be provided only on the second flat portion 41a. When a plurality of through holes 44 are provided, as shown in FIG. 5F, one through hole 44 may be provided on the second flat portion 41a and another through hole 44 may be provided on the standing surface portion 41b. The shape of the through hole 44 is substantially rectangular. However, it is not particularly limited, and various shapes can be adopted.

[0021] The second external connection portion 42 is provided so as to extend in a lateral direction from the upper end of the standing surface portion 41b and in a direction opposite to the second flat portion 41a in a plan view. This second external connection portion 42 is laterally displaced from the first external connection portion 32 in a plan view and does not face the first external connection portion 32 (see FIG. 4).

[0022] As shown in FIG. 1, the case 5 includes a bottom portion 51 having a substantially rectangular shape in a plan view, side wall portions 52 that rise upward from four sides of the bottom portion 51, and an opening portion 53 that opens on the bottom portion 51. The capacitor element 2, the first bus bar 3, and the second bus bar 4 are housed in the case 5 through the opening portion 53. Further, the first external connection portion 32 and the second external connection portion 42 extend out of the case 5 from this opening portion 53. This case 5 is made of a non-conductive material such as synthetic resin, for example.

[0023] Incidentally, case 5 is equipped with a projection 54. This projection 54 is roughly rectangular in side view and extends from the bottom 51 and side wall 52 toward the opening 53 of case 5, forming a gap G between it and the inner surface 52a of the side wall 52 (see Figure 2). Hereinafter, the part that forms the gap G will be called the gap-forming part 54a, and the part that connects the lower part of the gap-forming part 54a to the bottom 51 and side wall 52 of case 5 will be called the connecting part 54b. Both the gap-forming part 54a and the connecting part 54b are part of case 5 and are integrated together.

[0024] The gap-forming portion 54a is roughly rectangular in shape when viewed from the side and is roughly plate-shaped. It is provided roughly parallel to the inner surface 52a of the side wall portion 52 and facing the inner surface 52a of the side wall portion 52. The gap G is open on three sides: upward (towards the opening 53 of the case 5) and left and right, and closed downward (towards the bottom 51 of the case 5). The spacing of the gap G is the same as or slightly less than the thickness of the vertical portion 41b. Therefore, when the vertical portion 41b is located within the gap G, the movement of the vertical portion 41b is restrained. That is, it functions to position the second bus bar 4 and the capacitor element 2 connected to the second bus bar 4 within the case 5, and to prevent the capacitor element 2 from floating up. In addition, the upper end of the gap-forming portion 54a is located higher than the first electrode surface 21, ensuring the necessary edge distance between the first electrode surface 21 and the vertical portion 41b. That is, it ensures insulation between the first electrode surface 21 and the vertical portion 41b.

[0025] The connecting portion 54b has an upper surface portion 54b1 that forms the bottom of the gap G. The inner circumferential surface of the through hole 44 abuts against this upper surface portion 54b1 from above. That is, it functions as a vertical positioning component. The connecting portion 54b also has a side surface portion 54b2 that the inner circumferential surface of the through hole 44 can abut against from the side. Therefore, the connecting portion 54b also functions as a horizontal positioning component in Figure 1.

[0026] Multiple projections 54 (four in Figure 1) are provided in the above configuration. Specifically, the same number of projections 54 are provided as the number of through holes 44 provided in the second bus bar 4.

[0027] A protruding portion 52b is provided on the inner surface 52a of the side wall portion 52 in close proximity to the gap-forming portion 54a. This protruding portion 52b is formed by causing the inner surface 52a of the side wall portion 52 to protrude toward the gap-forming portion 54a, and as a result, in a plan view, the gap G protrudes toward the inside of the case 5. This ensures the necessary resin thickness for the capacitor element 2 (distance from the capacitor element 2 to the outer surface of the side wall portion 52).

[0028] The filler 6 that is filled into the case 5 is, for example, a thermoplastic resin, specifically, an epoxy resin. However, various known resins such as urethane resin can be used. It is preferable to use a resin with excellent moisture resistance and high thermal conductivity. The resin is filled so that the capacitor element 2, as well as the first substrate portion 31 and the second substrate portion 41, are embedded. The first external connection portion 32 and the second external connection portion 42 are exposed outside the resin. The resin thickness (distance from the resin surface to the capacitor element 2) is appropriately changed depending on the type and characteristics of the resin used. Furthermore, the filler is not limited to resin; insulating oil may also be used.

[0029] Next, the assembly of capacitor 1 will be described. First, the first planar portion 31a of the first busbar 3 is superimposed on the first electrode surface 21 of the capacitor element 2 and connected and fixed by soldering or the like, and the second planar portion 41a of the second busbar 4 is superimposed on the second electrode surface 22 and connected and fixed by soldering or the like to form a capacitor module. At this time, the second busbar 4 is positioned so that the first external connection portion 32 and the second external connection portion 42 face in the same direction, and the vertical portion 41b of the second busbar is aligned with the side surface 24 of the capacitor element 2 (S1 in Figure 3).

[0030] Next, the capacitor module is housed in the case 5 through the upper opening 53. At this time, the first external connection part 32 and the second external connection part 42 are housed facing upwards so that they extend out of the case 5 through the opening 53. The projection 54 is inserted through the through hole 44 provided in the vertical surface part 41b, and the part of the vertical surface part 41b above the through hole 44 (insertion part) 45 is inserted from top to bottom (from the opening 53 side to the bottom 51 side) into the gap G between the projection 54 and the side wall part 52. In other words, the insertion part 45 of the vertical surface part 41b is sandwiched between the projection 54 and the side wall part 52 (see S2 in Figure 3). Then, the manufacturing of the capacitor 1 is completed by filling the case 5 with filler material 6. The filler material 6 is filled until at least the capacitor element 2 and the insertion part 45 are located inside the filler material 6.

[0031] In the capacitor 1 with the above configuration, the case 5 integrally provides a projection 54 that functions as an insulator between the first electrode surface 21 and the second busbar 4. Therefore, there is no need to provide a separate insulating material to ensure insulation between the first electrode surface 21 and the second busbar 4, thereby reducing costs and man-hours. Furthermore, the projection 54 also functions to position the capacitor element 2 via the second busbar 4 and prevent it from floating up. This ensures that the position of the capacitor element 2 within the case 5 is fixed, and while ensuring the necessary resin thickness is secured, it is not necessary to add extra thickness, thus allowing the entire capacitor to be miniaturized.

[0032] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be implemented with various modifications within the scope of the present invention. For example, in the above embodiment, a through hole 44 was provided in the vertical surface portion 41b in order to sandwich the vertical surface portion 41b between the gap-forming portion 54a of the projection 54 and the protruding portion 52b of the side wall portion 52, but it is not necessarily required to be a through hole 44, and a notch 44A (see Figures 5D and E) may also be used. In short, it is sufficient that an insertion portion 45 is formed that can be inserted into the gap G from the opening 53 side of the case 5.

[0033] Furthermore, the projection 54 may have any shape. For example, in addition to being plate-shaped, it can be pin-shaped, prismatic, or any other shape. Also, for example, the projection 54 may have a barb 54a1 that catches on the periphery of the through hole 44 or around the notch 44A. The barb 54a1 makes it difficult for the second bus bar 4 to come out of the projection 54 (after the projection 54 is inserted through the through hole 44 or notch 44A, the upward movement of the second bus bar 4 (towards the case opening) is restricted). Furthermore, the barb 54a1 may also have any shape. The shape of the projection 54 and the barb 54a1 may be, for example, an inverted convex shape as shown in Figure 6A, a male shape of a side-release buckle as shown in Figure 6B, an arrow shape as shown in Figure 6C, a rectangle with a notch on one side of the lower part as shown in Figure 6D, or a triangle with a notch on one side of the lower part as shown in Figure 6E, or an oblique or curved shape as shown in Figures 6F and G. In short, it is sufficient to have a portion that protrudes laterally in the vertical direction (from the bottom 51 of the case toward the opening 53). The projection 54 may be attached by inserting the projection 54 through the through hole 44 or notch 44A and then sliding the second busbar 4 laterally (towards the return 54a1 side), or it may be pushed into the through hole 44, which has a width smaller than the width of the portion where the return 54a1 is provided, while being elastically deformed.

[0034] Furthermore, as shown in Figures 7A to C, a fold 54a2 may be provided at the upper end of the projection 54. When the fold 54a2 is directed toward the vertical surface portion 41b, positioning and prevention of lifting become more reliable. When the fold 54a2 is directed toward the capacitor element 2, the reliability of insulation increases. In Figure 7A, the fold 54a2 is directed toward both the capacitor element 2 and the vertical surface portion 41b. In Figures 7B and C, it is directed toward only the capacitor element 2. It may also be directed toward only the vertical surface portion 41b.

[0035] Furthermore, although the lower part of the projection 54 was in contact with the bottom 51 and the side wall 52 of the case 5, it may also be in contact with only the bottom 51 or only the side wall 52. In other words, the projection 54 may extend from either the bottom 51 or the side wall 52. Also, the side wall 52 that forms a gap G with the projection 54 is not limited to one, but may be multiple. For example, if the vertical surface 41b faces multiple side wall 52, a projection 54 may be provided for each of the side wall 52. In this way, the projection 54 can be interposed between the first electrode surface 21 and the vertical surface 41b.

[0036] Alternatively, the through-hole 44 may be made larger than the projection 54 to allow for some clearance. In this case, even without strict precision, the projection 54 can be easily inserted through the through-hole 44, improving work efficiency and yield. [Explanation of Symbols]

[0037] 1 Capacitor 2 Capacitor elements 21 1st electrode surface 22 Second electrode surface 23 Bulge 24 Side view 24a Flat area 24b Curved section 3. First bus bar 31 First substrate section 31a 1st plane part 31b Rising section 32 First external connection section 33 connecting pieces 4. Second bus bar 41 Second circuit board section 41a 2nd plane part 41b Elevation 42 Second External Connection Section 43 connecting pieces 44 Through holes 44A Notch 45 Insertion part 5 cases 51 Bottom 52 Side wall section 52a Inner surface 52b Protruding section 53 Opening 54 Protrusion 54a Gap forming section 54a1 Reply 54a2 Turn back 54b Connection part 54b1 Top part 54b2 Side part 6 Filling G Gap

Claims

1. a case having a bottom, a sidewall, and an opening; a capacitor element housed in the case with a first electrode surface facing an opening of the case and a second electrode surface facing a bottom of the case; a first bus bar connected to the first electrode surface; a second bus bar connected to the second electrode surface; a filler to be filled in the case, the case further has a protrusion extending from the bottom and / or the side wall portion to form a gap between the protrusion and an inner surface of the side wall portion; the second bus bar has an upright portion extending toward the opening of the case along a side surface of the capacitor element, A capacitor characterized in that the protrusion is interposed between the first electrode surface and the upright portion by inserting the upright portion into a gap between the protrusion and the side wall portion.

2. 2. The capacitor according to claim 1, further comprising a protruding portion that causes the gap to protrude toward the inside of the case.

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