Film capacitor

Abstract

To surely and inexpensively perform positioning when a capacitor element and a bus bar are housed in a case.SOLUTION: The engagement portions 26,36 are formed at the second bent portions 24,34 of the first and second bus bars 2 and 3, the protruding portions 41 are formed at the positions of the inner surfaces of the case 4 facing the first and second bus bars 2 and 3, and the protruding portions 41 of the case 4 are engaged with the engagement portions 26,36 of the first and second bus bars 2 and 3 and positioned when the capacitor unit is accommodated in the case 4.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a film capacitor that is sealed with sealing resin while a capacitor element and portions of first and second bus bars electrically connected to a pair of end surface electrodes of the capacitor element are housed in an accommodation space of a case. [Background technology]

[0002] Conventionally, there has been a film capacitor that includes a capacitor element having a pair of end electrodes, a pair of lead terminals (also called bus bars) electrically connected to the pair of end electrodes of the capacitor element, a case with an opening on one side and an internal housing portion that houses the capacitor element and portions of the pair of lead terminals in a housing space within the housing portion, and a sealing resin that seals the inside of the case with the capacitor element and portions of the pair of lead terminals housed in the housing portion (see Patent Document 1).In recent years, inverter devices have been widely used to control electrical equipment, industrial equipment, automobiles, etc., and film capacitors are used in such inverter devices. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5796155 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of the film capacitor described in Patent Document 1 above, in order to facilitate positioning when housing the capacitor element and a portion of the pair of lead terminals within the case, positioning structures are provided on the lead terminals and the case, thereby improving the efficiency of the assembly work.

[0005] Specifically, a terminal positioning rib is formed on the inner surface of the case, and a terminal fixing portion that extends from the conductive plate and fits into the terminal positioning rib is formed on the lead terminal formed by processing a conductive plate into a long length. When the lead terminal is connected to the end surface electrode of the capacitor element and the capacitor element and lead terminal are housed in the case, the terminal positioning rib of the case fits into the terminal fixing portion of the lead terminal, and the bent surface that extends from the side of the conductive plate of the terminal fixing portion comes into surface contact with the inner surface of the case, thereby positioning the capacitor element.

[0006] However, in the film capacitor described in Patent Document 1, the terminal fixing portion extends from the conductive plate at a position that is not part of the current path of the lead terminal (bus bar), so a terminal fixing portion must be formed separately for positioning at a location other than the current path of the lead terminal, resulting in increased material and processing costs for the lead terminal. Furthermore, the terminal fixing portion extends from the conductive plate toward the inner surface of the case (the extension direction of the conductive plate is perpendicular to the inner surface of the case), is bent along the inner surface of the case, and the bent surface is in surface contact with the inner surface of the case, so if there is variation in the dimensions or processing of the capacitor element or lead terminal, it may be difficult to fit the case and the lead terminal.

[0007] The present invention has been made in view of the above-mentioned problems, and has an object to reliably and inexpensively position a capacitor element and a bus bar when housing them in a case. [Means for solving the problem]

[0008] In order to achieve the above object, a film capacitor according to the present invention comprises a capacitor element having a pair of end surface electrodes, a pair of bus bars electrically connected to the pair of end surface electrodes, respectively, and a case having an opening and an internal storage space, the film capacitor being sealed with a sealing resin in a state in which the capacitor element and a portion of the pair of bus bars are housed in the storage space, wherein at least one specific bus bar of the pair of bus bars is formed of an elastically deformable conductor and has an electrode connection portion electrically connected to the end surface electrodes and a terminal portion formed integrally with the electrode connection portion and connected to an internal surface of the case. a connecting portion extending continuously from the first bend portion, a second bend portion bending along the inner surface of the case on the opposite side of the connecting portion from the first bend portion, and an external connection terminal portion extending continuously from the second bend portion along the inner surface of the case, a portion of which is exposed to the outside of the case from the opening surface and is connected to an external terminal; the case has a protrusion protruding toward the specific bus bar on its inner surface facing the specific bus bar, and an engagement portion is formed at the second bend portion of the specific bus bar to engage with the protrusion of the case.

[0009] According to this configuration, the engagement portion that engages with the protrusion of the case is formed in the second bent portion that is formed continuously between the electrode connection portion and the external connection terminal portion. In other words, the engagement portion that contributes to positioning is formed on the current path of the specific bus bar, which does not increase material costs or processing costs. Furthermore, the specific bus bar is formed from an elastically deformable conductor, and the second bent portion where the engagement portion is formed bends from the connecting portion to the inner surface of the case on the opposite side from the first bent portion. This allows the case and lead terminals to be fitted together while accommodating variations in the dimensions and processing of the capacitor element and lead terminals. As a result, positioning of the capacitor element and bus bar when housed in the case can be performed reliably and inexpensively.

[0010] Here, the specific bus bar may be configured to have a through hole formed therethrough in the thickness direction as an engaging portion, and the inner wall of the through hole may be configured to engage with the protruding portion of the case.

[0011] According to this configuration, the inner wall of the through hole formed in the specific bus bar engages with the protrusion of the case, thereby enabling the specific bus bar and the capacitor element to be reliably positioned.

[0012] Preferably, the protruding portion has a smaller protruding amount at the opening side than at the bottom side of the case, and when the protruding portion at the bottom side engages with the engaging portion, the protruding portion at the opening side is located between the external connection terminal and the inner surface of the case that faces the specific bus bar, forming a gap between the inner surface of the case that faces the specific bus bar and the external connection terminal. In this case, the protruding portion may have a step that is approximately parallel to the opening side, and the protruding amount of the protruding portion at the opening side may be smaller than the protruding portion at the bottom side.

[0013] According to this configuration, when the sealing resin is filled, it is possible to prevent the sealing resin from creeping up between the inner surface of the case and the specific bus bar due to capillary action.

[0014] The protruding portion may be formed with an inclined portion whose protruding amount increases from the opening side toward the bottom side of the case.

[0015] According to this configuration, when the capacitor element and a portion of a pair of bus bars are accommodated in the storage space of the case, the protrusion and the engagement portion are engaged, and the inclined portion of the protrusion abuts against the upper end of the engagement portion, thereby forming a gap between the inner surface of the case facing the specific bus bar and the external connection terminal portion.

[0016] It is also preferable that the external connection terminal portion is bent multiple times, and the specific bus bar is arranged so that the tip of the bent external connection terminal portion contacts the peripheral surface of the capacitor element excluding the end surface electrodes.

[0017] According to this configuration, heat generated by the capacitor element can be dissipated via the external connection terminal portion. [Effects of the Invention]

[0018] According to the present invention, the capacitor element and the bus bar can be positioned reliably and inexpensively when housed in the case. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a perspective view of a film capacitor according to a first embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view of the film capacitor of FIG. 1 without a case and a sealing resin. [Figure 3] FIG. 3 is a front view of the film capacitor of FIG. 2. [Figure 4] FIG. 2 is a perspective view of a capacitor element of the film capacitor of FIG. [Figure 5] FIG. 2 is a perspective view of a first bus bar of the film capacitor of FIG. [Figure 6] FIG. 2 is a perspective view of the case of the film capacitor shown in FIG. 1 as seen from above. [Figure 7] FIG. 7 is a plan view of the case of FIG. 6. [Figure 8] 2 is a plan view of the film capacitor of FIG. 1 in a state where the capacitor element and sealing resin are not present. [Figure 9] 9 is a perspective view showing a cross section of the film capacitor of FIG. 8 taken along line LL. [Figure 10] 10 is a diagram showing a main part of an engagement portion between the second bus bar and the case in FIG. 9. FIG. [Figure 11] FIG. 10 is a front view of the film capacitor according to the second embodiment of the present invention without the case and sealing resin. [Figure 12] FIG. 12 is a perspective view of the first and second bus bars of the film capacitor of FIG. [Figure 13] FIG. 10 is a perspective view of a protrusion of a film capacitor according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] First Embodiment A first embodiment of a film capacitor according to the present invention will be described in detail with reference to FIGS.

[0021] The configuration of a film capacitor 1, which is a capacitor according to a first embodiment, will be described with reference to FIGS. 1 to 10. In FIGS. 1 to 10, the x-axis, y-axis, and z-axis are illustrated so that they are all aligned in the same direction. Hereinafter, the positive and negative x-axis sides will be referred to as the right and left, the positive and negative y-axis sides as the rear and front, and the positive and negative z-axis sides as the top and bottom. Hereinafter, a planar view of the film capacitor 1 viewed from the positive (top) or negative (bottom) side of the z-axis to the negative (bottom) or positive (top) side of the z-axis will be referred to as an "xy planar view," a planar view of the film capacitor 1 viewed from the positive (top) or negative (bottom) side of the y-axis to the negative (front) or positive (rear) side of the y-axis will be referred to as an "xz planar view," and a planar view of the negative (left) or positive (right) side of the x-axis from the positive (right) or negative (left) side of the x-axis will be referred to as a "yz planar view."

[0022] As shown in FIGS. 1 to 10, the film capacitor 1 includes a capacitor unit (capacitor element 10, first bus bar 2, second bus bar 3) with end surface electrodes arranged parallel to the yz plane, a case 4, and a sealing resin 5.

[0023] 4, capacitor element 10 has element body 11, first end surface electrode 12 formed by spraying a metal such as zinc on the left side surface of element body 11 on the negative side of the x-axis, and second end surface electrode 13 formed by spraying a metal such as zinc on the right side surface of element body 11 on the positive side of the x-axis. Note that first end surface electrode 12 and second end surface electrode 13 of capacitor element 10 correspond to the "pair of end surface electrodes" of the capacitor element in the present invention.

[0024] The element body 11 is formed by overlapping two metallized films, each of which is formed by depositing aluminum on a dielectric film, and rolling or laminating them, and then pressing them into a flat shape. Note that the metallized film is not limited to the above-described configuration formed by depositing aluminum on a dielectric film. For example, the metallized film may be a metallized film deposited with other metals such as zinc or magnesium, a metallized film deposited with multiple of these metals, or a metallized film deposited with an alloy of these metals.

[0025] The first end surface electrode 12 is used as a P-pole side, and the second end surface electrode 13 is used as an N-pole side. Alternatively, the first end surface electrode 12 may be used as an N-pole side, and the second end surface electrode 13 may be used as a P-pole side.

[0026] The first bus bar 2 and the second bus bar 3 are each formed by punching an elastically deformable conductive material such as copper. As shown in Figures 1 to 3 and 5, the first bus bar 2 has an electrode connection portion 20, a first bent portion 22, a linking portion 23, a second bent portion 24, and an external connection terminal portion 25.

[0027] The electrode connection portion 20 is disposed opposite to and in contact with the first end surface electrode of the capacitor element 10, and has a connection pin 21. The connection pin 21 is integrally formed at the lower end of the electrode connection portion 20 on the negative side of the z axis and at the rear end on the positive side of the y axis, extending in the negative direction of the z axis, and is soldered to the first end surface electrode 12 to electrically connect the first bus bar 2 and the first end surface electrode 12.

[0028] The first bent portion 22 is integrally formed at the upper end of the electrode connection portion 20 on the positive side of the z axis, and is inclined in the negative direction of the x axis (to the left) with respect to the yz plane, bending away from the first end surface electrode 12 toward the inner surface of the case 4. The connecting portion 23 is integrally formed so as to be continuous with the first bent portion 22 and extend toward the inner surface of the case 4. The second bent portion 24 is integrally formed on the opposite side of the connecting portion 23 to the first bent portion 22, and is bent toward the positive direction of the z axis (upward) with respect to the xy plane, bending along the inner surface of the case 4. External connection terminal portion 25 has an extending portion 25a that is integrally formed so as to extend upward (in the positive direction of the z-axis) continuous with second bent portion 24 along the inner surface of case 4, a first bent portion 25b that is integrally formed at the upper end of extending portion 25a on the positive side of the z-axis so as to be bent at approximately 90 degrees to the right in the positive direction of the x-axis, and a second bent portion 25c that is integrally formed at the right end of first bent portion 25b on the positive side of the x-axis so as to be bent downward at approximately 90 degrees in the negative direction of the z-axis. First bent portion 25b is electrically connected to an external terminal (not shown).

[0029] The first busbar 2 is arranged in a state in which all but the upper end portions of the extension portion 25a and the second bent portion 25c of the external connection terminal portion 25 are buried in the sealing resin 5, and the upper end portions of the extension portion 25a and the second bent portion 25c, as well as the entire first bent portion 25b, are exposed from the sealing resin 5.

[0030] The second bent portion 24 has two engagement portions 26, 26 formed by through holes that penetrate the first bus bar 2 in the thickness direction at positions closer to the negative side (front side) than the center of the y axis. As will be described in detail later, these engagement portions 26, 26 are engaged with a pair of protrusions formed on the inner surface of the case 4, and this engagement determines the positioning of the capacitor unit when it is housed in the case 4.

[0031] At this time, when an external force acts on extending portion 25a of external connection terminal portion 25 to the right (positive direction of the x-axis) while electrode connecting portion 20 is in surface contact with first end surface electrode 12 of capacitor element 10, second bent portion 24 exerts a biasing force on first bent portion 22 in the direction opposite to the external force, and first and second bent portions 22, 24 are bent and displaced in the direction of the external force without changing the connection position of first bent portion 25b with the external terminal. Therefore, even if an external force acts on extending portion 25a of external connection terminal portion 25 to the right (positive direction of the x-axis) when the capacitor unit is housed in case 4, the bending of first and second bent portions 22, 24 mitigates the effect of the external force.

[0032] Furthermore, the tip of second bent portion 25c of external connection terminal portion 25 on the negative side of the z-axis is arranged in contact with the circumferential surface of capacitor element 10 excluding first end surface electrode 12 and second end surface electrode 13 located on the positive side of the z-axis. Due to this contact arrangement of second bent portion 25c of external connection terminal portion 25, heat generated by capacitor element 10 is efficiently dissipated to the outside via first bus bar 2.

[0033] 1 to 3, like the first bus bar 2, the second bus bar 3 includes an electrode connection portion 30 having a connection pin 31, a first bent portion 32, a connecting portion 33, a second bent portion 34, an external connection terminal portion 35 (extending portion 35a, first bent portion 35b, second bent portion 35c), and two engagement portions 36, 36, and the first and second bus bars 2, 3 are connected to the first and second end surface electrodes 12, 13 of the capacitor element 10, respectively, with the second bent portion 35c of the external connection terminal portion 35 arranged opposite the second bent portion 25c of the first bus bar 2. At this time, the first and second bus bars 2, 3 are housed in the case 4 so that the centers of the first and second bus bars 2, 3 in the y-axis direction coincide with the center of the case 4 in the y-axis direction.

[0034] Since the second busbar 3 has the same external shape as the first busbar 2, a stamped piece of elastically deformable conductive material such as copper can be used for either the first busbar 2 or the second busbar 3, depending on whether it is used on the P side or the N side. Compared to when the first and second busbars 2, 3 have different shapes, only one type of stamping mold is required, which helps prevent costs from increasing.

[0035] Similarly to the first busbar 2, when an external force acts to the left (negative x-axis direction) on the extension portion 35a of the second busbar 3 when the capacitor unit is housed in the case 4, the first and second bent portions 32, 34 bend and displace in the direction of the external force without changing the connection position of the first bent portion 35b with the external terminal, thereby mitigating the effects of the external force.

[0036] 1, 6, and 7, the case 4 has a rectangular parallelepiped housing shape with an opening 4a on the upper surface on the positive side of the z-axis and an internal storage space forming storage section 4b, and can be formed from various materials, for example, organic materials such as resins and plastics such as polyphenylene sulfide (PPS) and polybutylene terephthalate (PBT), and inorganic materials such as ceramics. The case 4 corresponds to the "case" in this invention.

[0037] A portion of a capacitor unit (the capacitor element, a portion of the first bus bar 2, and a portion of the second bus bar 3) having the capacitor element 10, the first bus bar 2, and the second bus bar 3 is accommodated in the accommodation portion 4b of the case 4. Furthermore, a liquid sealing resin 5 made of, for example, epoxy resin is filled into the accommodation portion 4b of the case 4 that accommodates the portion of the capacitor unit, thereby sealing the portion of the capacitor unit.

[0038] The sealing resin 5 is not limited to epoxy resin, and various insulating materials used as sealing resins for electronic components can be used. The sealing resin 5 is poured into the case 4 from the opening 4a in a liquid state and then hardens. The sealing resin 5 corresponds to the "sealing resin" in this invention.

[0039] 6 and 7, a pair of rectangular parallelepiped protrusions 41, 41 protruding in the z-axis direction toward the first and second bus bars 2, 3 are formed on each of the left and right inner surfaces of the case 4 that are parallel to the yz plane and face the first and second bus bars 2, 3. The protrusions 41, 41 on the left inner surface on the negative side of the x-axis of the case 4 are formed side by side at a position closer to the negative side (front side) than the center of the inner surface in the y-axis direction, and the protrusions 41, 41 on the right inner surface on the positive side of the x-axis of the case 4 are formed side by side at a position closer to the positive side (rear side) than the center of the inner surface in the y-axis direction.

[0040] 10, the amount of protrusion of each protrusion 41 is smaller at protrusion portion 411 on the opening surface side than at protrusion portion 412 on the bottom surface side of case 4, and step portions 42 parallel to opening surface 4a (xy plane) are formed at the boundary where the amount of protrusion of each protrusion 41 changes. As shown in FIGS. 9 and 10, which are cross-sectional views taken along line LL in the center in the z-axis direction shown in FIG. 8, when a capacitor unit in which first and second bus bars 2, 3 are connected to capacitor element 10 is accommodated in accommodation portion 4b of case 4, each protrusion 41 is accommodated so as to engage with engagement portions 26, 36 of the first and second bus bars 2, 3.

[0041] At this time, the step portions 42 of each protrusion 41 engage with the engagement portions (inner walls of the through holes) 26, 36 of the first and second bus bars 2, 3, thereby positioning them in the positive and negative y-axis directions, and the step portions 42 of each protrusion 41 abut against the upper ends of the engagement portions 26, 36 of the first and second bus bars 2, 3 (the surfaces of the inner walls of the through holes facing the negative z-axis direction), thereby positioning them in the negative z-axis direction, and the protrusion portions 411 on the opening side of each protrusion 41, which have a smaller protrusion amount, come into contact with the extending portions 25a, 35a of the first and second bus bars 2, 3. At this time, the pressing force from the side of each protrusion portion 411 and the bending force due to the elasticity of the extending portions 25a, 35a of the first and second bus bars 2, 3 cancel each other out, thereby positioning them in the positive and negative x-axis directions and the positive z-axis direction. In this way, the first and second bus bars 2, 3 are positioned without changing the connection positions of the first bent portions 25b, 35b with the external terminals, and a gap G is formed between the inner surface of the case 4, where the first and second bus bars 2, 3 face, and the extending portions 25a, 35a of the first and second bus bars 2, 3, with the protruding portions 411 on the opening side of each protruding portion 41 interposed. Note that the protruding portions 412 on the bottom side of the step portions 42 of each protruding portion 41 may come into contact with the electrode connecting portions 20, 30 of the first and second bus bars 2, 3.

[0042] In this way, by forming a gap G between the inner surface of the case 4 facing the first and second bus bars 2, 3 and the extension portions 25a, 35a of the first and second bus bars 2, 3, creeping up due to capillary action is suppressed when filling the sealing resin 5, and resin leakage during filling can be prevented in advance.

[0043] Furthermore, when the capacitor unit is housed in the case 4, even if a pressing force acts on the extension portion 25a of the first bus bar 2 in the positive direction of the x-axis (to the right) and a pressing force acts on the extension portion 35a of the second bus bar 3 in the negative direction of the x-axis (to the left), the first bent portions 22, 32 and the second bent portions 24, 34 bend and displace in the direction of the external force without changing the connection positions of the first bent portions 25b, 35b with the external terminals, thereby mitigating the effect of the external force.

[0044] The step portions 42 of each protrusion 41 engage with the engagement portions 26, 36 of the first and second bus bars 2, 3, thereby positioning the first and second bus bars 2, 3 in the positive and negative y-axis directions, and the step portions 42 of each protrusion 41 abut against the upper ends of the engagement portions 26, 36 of the first and second bus bars 2, 3, thereby positioning the first and second bus bars 2, 3 in the positive and negative x-axis directions and the positive z-axis direction. Thus, the first and second bus bars 2, 3 are positioned without changing the connection positions of the first bent portions 25b, 35b with the external terminals, and a gap G is formed between the inner surface of the case 4 facing the first and second bus bars 2, 3 and the extension portions 25a, 35a of the first and second bus bars 2, 3.

[0045] Furthermore, the tips of the second bent portions 25c, 35c of the first and second bus bars 2, 3 come into contact with the circumferential surface of the element body portion 11 of the capacitor element 10, and while this contact state is maintained, part of the capacitor unit (the capacitor element, part of the first bus bar 2, and part of the second bus bar 3) is sealed with the sealing resin 5. At this time, with the tips of the second bent portions 25c, 35c of the first and second bus bars 2, 3 in contact with the circumferential surface of the capacitor element 10 excluding the first and second end surface electrodes 12, 13, the upper ends of the extending portions 25a, 35a of the first and second bus bars 2, 3, the entire first bent portions 25b, 35b, and the upper ends of the second bent portions 25c, 35c are exposed from the sealing resin 5. Therefore, heat generated by the capacitor element 10 can be efficiently dissipated to the outside via the exposed parts of the first and second bus bars 2, 3.

[0046] Therefore, according to the first embodiment described above, a pair of engagement portions 26, 36 are formed on each of the first and second bus bars 2, 3, and a protrusion 41 is formed on the inner surface of the case 4 facing the engagement portions 26, 36 of the first and second bus bars 2, 3, so that the protrusion 41 engages with the engagement portions 26, 36 of the first and second bus bars 2, 3. As a result, the capacitor unit can be easily and reliably positioned when accommodated in the case 4.

[0047] Second Embodiment A second embodiment of a film capacitor according to the present invention will be described in detail with reference to Figures 11 and 12. Differences from the first embodiment will be described below, with reference to Figures 1 to 10. Note that in these figures, the x-axis, y-axis, and z-axis are illustrated so that they are in the same direction, just like the x-axis, y-axis, and z-axis in Figures 1 to 10.

[0048] In the film capacitor 1 according to the second embodiment, the shapes of the first and second bus bars 2A and 3A are different from those of the first embodiment. That is, the first bus bar 2A according to the second embodiment includes an electrode connecting portion 20A having a connection pin 21A, a first bent portion 22A, a connecting portion 23A, a second bent portion 24A, and an external connection terminal portion 25A (extending portion 25Aa, first bent portion 25Ab, second bent portion 25Ac). The second bus bar 3A includes an electrode connecting portion 30A having a connection pin 31A, a first bent portion 32A, a connecting portion 33A, a second bent portion 34A, and an external connection terminal portion 35A (extending portion 35Aa, first bent portion 35Ab, second bent portion 35Ac).

[0049] In the first embodiment, first bent portions 22, 32 are integrally formed at the upper end of electrode connection portion 20 on the positive side of the z axis in the negative x-axis direction with respect to the yz plane, and at the upper end of electrode connection portion 30 on the positive side of the z axis in the positive x-axis direction with respect to the yz plane, so as to bend away from first and second end surface electrodes 12, 13 and toward the inner surface of case 4; connecting portions 23, 33 extend from first bent portions 22, 32 toward the inner surface of case 4; and second bent portions 24, 34 are integrally formed on the opposite side of connecting portions 23, 33 from first bent portions 22, 32, so as to bend toward the positive z-axis direction (upward) with respect to the xy plane and along the inner surface of case 4. However, in the second embodiment, as shown in Figures 11 and 12, the upper ends of the electrode connection portions 20A, 30A on the positive side of the z axis are integrally formed with first bent portions 22A, 32A that bend at approximately 90 degrees away from the first and second end surface electrodes 12A, 13A and toward the inner surface of the case 4A, connecting portions 23A, 33A that are continuous with the first bent portions 22A, 32A and extend toward the inner surface of the case 4A, and second bent portions 24A, 34A that are on the opposite side of the connecting portions 23A, 33A from the first bent portions 22A, 32A and face in the positive direction of the z axis with respect to the xy plane, and bend at approximately 90 degrees to fit along the inner surface of the case 4A.

[0050] 12, the first bus bar 2A has a pair of through-hole-shaped engagement portions 26A, 26A elongated in the z-axis direction formed by through-holes that penetrate the thickness direction of the first bus bar 2 at two locations on the second bent portion 24A closer to the negative side than the center of the y-axis. Similar engagement portions 36A, 36A are also formed in the second bent portion 34A of the second bus bar 3A.

[0051] As in the first embodiment, when a capacitor unit in which the first and second bus bars 2A, 3A are connected to the capacitor element 10 is accommodated in the accommodation section 4b of the case 4, each protrusion 41 engages with the engagement portions 26A, 36A of the first and second bus bars 2A, 3A, respectively.

[0052] At this time, as in the first embodiment, positioning in the positive and negative y-axis directions is achieved by the step portions 42 of each protrusion 41 engaging with the engagement portions 26A and 36A of the first and second bus bars 2A and 3A, and positioning in the negative z-axis direction is achieved by the step portions 42 of each protrusion 41 abutting against the upper ends of the engagement portions 26A and 36A of the first and second bus bars 2A and 3A. Furthermore, as the protruding portion 411 on the opening side of each protruding portion 41, which has a small protruding amount, comes into contact with the extending portions 25Aa, 35Aa of the first and second bus bars 2A, 3A, the pushing force from the upper side of each protruding portion 41 and the bending force due to the elasticity of the extending portions 25Aa, 35Aa of the first and second bus bars 2A, 3A are offset, thereby positioning the first and second bus bars 2A, 3A in the positive and negative x-axis directions and the positive z-axis direction, and the first and second bus bars 2A, 3A are positioned without changing the connection position of the first bent portions 25Ab, 35Ab with the external terminals, and a gap is formed between the inner surface of the case 4 facing the first and second bus bars 2A, 3A and the extending portions 25a, 35a of the first and second bus bars 2A, 3A.

[0053] Therefore, according to the second embodiment, it is possible to obtain the same effects as those of the first embodiment.

[0054] Third Embodiment A third embodiment of the film capacitor according to the present invention will be described in detail with reference to FIG.

[0055] In the first embodiment described above, step portions 42 substantially parallel to opening surface 4a were formed so that the protruding amount of protruding portion 411 on the opening surface side was smaller than that of protruding portion 412 on the bottom surface side of protruding portion 41. However, in the third embodiment, as shown in Fig. 13, a pair of protruding portions 41A protruding in the z-axis direction toward the first and second bus bars on the inner surface of case 4 facing the first and second bus bars has inclined portions 42A such that the protruding amount gradually increases from the opening surface side toward the bottom surface side of case 4. The protruding amount of protruding portion 412A on the opening side of protruding portion 41A, which includes the upper part of inclined surface 42A, from the inner surface of the case is smaller than the protruding amount of protruding portion 412A on the bottom surface side of protruding portion 41A, which includes the lower part of inclined surface 42A.

[0056] In this case, the upper ends (the surfaces of the inner walls of the through holes facing the negative side of the z-axis) of the engagement portions (through holes) of the first and second bus bars abut midway along the inclined portions 42A of each protrusion 41A of the case 4, and the first and second bus bars are positioned with the protrusion portions 411A of the protrusion 41 above the abutment position on the opening surface side interposed between the inner surfaces of the case 4 facing the first and second bus bars and the extension portions of the first and second bus bars, forming a gap.

[0057] According to the third embodiment, it is possible to obtain the same effects as those of the first embodiment described above.

[0058] The present invention is not limited to the above-described configuration, and various design modifications can be made within the scope of the claims.

[0059] For example, in the above-described embodiment, a pair of engagement portions is formed on each of the first and second bus bars, and protrusions corresponding to these pairs of engagement portions are formed on the case. However, it is also possible to form one engagement portion on each of the first bus bar and the second bus bar, and form one protrusion on each of the positions on the inner surface of the case 4 corresponding to the engagement portions.

[0060] In addition, in the above-described embodiment, an engagement portion is formed on each of the first bus bar and the second bus bar, but it is also possible to designate either the first bus bar or the second bus bar as a specific bus bar and form one or more engagement portions only on that specific bus bar, and form corresponding protrusions on the inner surface of the case 4.

[0061] Furthermore, the protrusion does not have to be rectangular parallelepiped-shaped extending in the z-axis direction as shown in Figure 6, but may be a short protrusion in the z-axis direction protruding from the inner surface of the case 4 in a direction perpendicular to the opening surface 4a and having a shape that allows the engagement portion to engage.

[0062] The present invention is widely applicable to film capacitors that include a capacitor element having a pair of end surface electrodes, a first bus bar and a second bus bar electrically connected to each of the pair of end surface electrodes, and a case with an opening and an accommodating space inside, and that are sealed with a sealing resin with the capacitor element and portions of the first and second bus bars housed in the accommodating space. [Explanation of symbols]

[0063] 1...Film capacitor 2,2A...First bus bar 3,3A...Second bus bar 4. Case 4a…Aperture surface 5...Sealing resin 20, 20A, 30, 30A...Electrode connection part 21, 21A, 31, 31A ... Connection pins 22,22A,32,32A…1st bending part 23,23A,33,33A…Connection part 24,24A,34,34A…Second bending part 25, 25A, 35, 35A ... External connection terminal 26,26A, 36, 36A...Engagement part 41,41A...Protruding part 42...Double section 42A…Slope part

Claims

1. A film capacitor comprising: a capacitor element having a pair of end surface electrodes; a pair of bus bars electrically connected to the pair of end surface electrodes, respectively; and a case having an opening and an internal storage space, the case being sealed with a sealing resin with the capacitor element and a portion of the pair of bus bars housed in the storage space, At least one specific bus bar of the pair of bus bars is formed of an elastically deformable conductive material, an electrode connection portion electrically connected to the end surface electrode; a first bent portion integrally formed with the electrode connection portion and bent toward an inner surface of the case; a connecting portion extending continuously from the first bent portion; a second bent portion integrally formed on the connecting portion on the opposite side to the first bent portion and bent to fit along an inner surface of the case; an external connection terminal portion that is continuous with the second bent portion and extends along the inner surface of the case, a portion of which is exposed from the sealing resin and is electrically connected to an external terminal; the case has a protrusion on an inner surface facing the specific bus bar that protrudes toward the specific bus bar, a second bent portion of the specific bus bar having an engaging portion formed therein that engages with the protruding portion of the case;

2. The film capacitor according to claim 1, characterized in that a through hole penetrating the specific bus bar in the thickness direction is formed as the engagement portion, and an inner wall of the through hole engages with the protrusion of the case.

3. The protruding amount of the protruding portion is smaller on the opening side than on the bottom side of the case, The film capacitor described in claim 1, characterized in that when the protruding portion on the bottom surface engages with the engaging portion, the protruding portion on the opening surface is positioned between the external connection terminal portion and the inner surface of the case facing the specific bus bar, forming a gap between the inner surface of the case facing the specific bus bar and the external connection terminal portion.

4. The protrusion has a step portion formed thereon that is substantially parallel to the opening surface, 4. The film capacitor according to claim 3, wherein the protruding portion on the opening side is formed to have a smaller protruding amount than the protruding portion on the bottom side, with the step portion as a boundary.

5. 4. The film capacitor according to claim 3, wherein the protruding portion is provided with an inclined portion whose protruding amount increases from the opening side toward the bottom side of the case.

6. The film capacitor according to claim 1, characterized in that the external connection terminal portion is bent multiple times, and the specific bus bar is positioned so that the tip of the bent external connection terminal portion contacts the peripheral surface of the capacitor element excluding the end surface electrodes.

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