Capacitor

Abstract

To easily attach an external component to a lid member in a space above a film capacitor while improving the moisture resistance of the capacitor.SOLUTION: There is provided a capacitor in which a part of a sealing resin 6 exposed on the opening surface side of a case 5 is covered by a lid member 7, an engagement part 71 that engages with an external component to fix the external component to the lid member 7 is formed on a side, of the lid member 7, opposite the surface facing the sealing resin 6, and as viewed from a direction perpendicular to an opening surface of the case 5, the lid member 7 has a plane area larger than the total projection area of all capacitor elements 10 and is disposed in a position where the lid member 7 covers each capacitor element 10.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a capacitor in which bus bars are electrically connected to a pair of end electrodes of a capacitor element, and the capacitor element and parts of the pair of bus bars are housed in a case and sealed with sealing resin. [Background technology]

[0002] Conventionally, there has been a film capacitor that includes a capacitor element having a pair of end electrodes, a pair of bus bars electrically connected to the pair of end electrodes of the capacitor element, a case that has an opening on one side and an accommodating portion inside, the accommodating portion accommodating the capacitor element and parts of the pair of bus bars in an accommodating space, and a sealing resin that seals the inside of the case with the capacitor element and parts of the pair of bus bars accommodated in the accommodating portion.

[0003] This type of film capacitor is widely used in inverter equipment, and as inverter equipment becomes smaller and more powerful, there is an increasing demand for smaller film capacitors. However, the environmental performance required of film capacitors, such as moisture resistance, remains unchanged, so film capacitors are required to have high moisture resistance in addition to being smaller.

[0004] However, because a typical film capacitor has a large exposed area at the opening of the sealing resin case, moisture from the outside easily penetrates into the capacitor element through the sealing resin, causing a decrease in the moisture resistance of the film capacitor. Therefore, as described in Patent Document 1, for example, it has been proposed to cover the entire exposed surface on the upper side of the sealing resin with a synthetic resin plate to prevent moisture from penetrating into the capacitor element through the sealing resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-158775 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the configuration described in Patent Document 1 above, when an external component needs to be placed in the space above the film capacitor, the film capacitor itself does not have a configuration for attaching and fixing the external component, so the only options available are to prepare a separate mounting member for connecting the film capacitor and the external component and attach the external component to the capacitor using the mounting member, or to place the external component in another space.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to improve the moisture resistance of the capacitor by using a lid member while easily attaching external components to the space above the film capacitor. [Means for solving the problem]

[0008] In order to achieve the above object, a capacitor according to the present invention comprises a capacitor element having a pair of end electrodes, a first bus bar and a second bus bar electrically connected to the pair of end electrodes, respectively, and a case having an opening on one side and an accommodating portion inside, the case being sealed with sealing resin with the capacitor element and portions of the pair of bus bars accommodated in the accommodating portion, the capacitor further comprising a lid member covering at least a portion of the sealing resin exposed on the open side of the case, the lid member being positioned with respect to the sealing resin and having an engaging portion formed on a surface opposite to an opposing surface facing the sealing resin, the engaging portion engaging with an external component to fix the external component to the lid member.

[0009] With this configuration, the lid member prevents moisture from penetrating into the sealing resin side, improving the moisture resistance of the capacitor. When an external component is placed in the space on the side opposite the opposing surface of the lid member that faces the sealing resin, the external component can be stably fixed to the engaging portion of the lid member. This allows the lid member to easily attach an external component to the space above the film capacitor while improving the moisture resistance of the capacitor.

[0010] The lid member may further include a buried portion that is buried in the sealing resin to fix the lid member to the sealing resin.

[0011] According to this configuration, the buried portion is buried in the sealing resin, so that the lid member engaged with the external component can be firmly fixed to the sealing resin.

[0012] Furthermore, it is preferable that the cover member has a planar area larger than the projected area of ​​the capacitor element when viewed from a direction perpendicular to the opening surface, and is arranged in a position that covers the capacitor element when viewed from a direction perpendicular to the opening surface.

[0013] According to this configuration, the capacitor element is covered by the lid member when viewed from a direction perpendicular to the opening surface of the case, and the lid member can reliably prevent moisture from penetrating into the capacitor element through the sealing resin.

[0014] The embedded portion of the lid member may be formed to protrude toward the sealing resin side relative to the opposing surface.

[0015] According to this configuration, the lid member is placed on top of the sealing resin before the sealing resin hardens, and the buried portion is buried in the sealing resin, and the sealing resin is then hardened, thereby making it possible to firmly fix the lid member to the sealing resin.

[0016] Preferably, a metal fastening portion that can be fastened to the external component is insert-molded into the engaging portion.

[0017] According to this configuration, the fastening portion that engages with the external component can be formed in advance when the cover member is manufactured (molded).

[0018] It is also preferable that the cover member be made of a material that has better heat dissipation properties than the sealing resin.

[0019] According to this configuration, heat generated in the capacitor can be efficiently dissipated to the outside via the lid member, making it possible to provide a capacitor with excellent heat dissipation properties. [Effects of the Invention]

[0020] According to the present invention, it is possible to easily attach an external component to the cover member in the space above the film capacitor while improving the moisture resistance of the capacitor. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view of a capacitor unit (first bus bar not shown) included in a capacitor according to an embodiment of the present invention. [Figure 2] FIG. 1 is a plan view of a capacitor according to an embodiment. [Figure 3] FIG. 3 is a perspective view of the capacitor of FIG. 2. [Figure 4] FIG. 3 is a perspective view of a first bus bar of the capacitor of FIG. 2. [Figure 5] FIG. 3 is a perspective view of a second bus bar of the capacitor of FIG. 2. [Figure 6] FIG. 3 is a perspective view of a lid member of the capacitor of FIG. 2; [Figure 7] FIG. 3 is a front view of the lid member of the capacitor of FIG. [Figure 8] 3 is a perspective view of the lid member of the capacitor of FIG. 2, seen from the bottom side. [Figure 9] FIG. 3 is a perspective view of the connection wires of the capacitor in FIG. 2. [Figure 10] 3 is a front view illustrating the positional relationship between the lid member of the capacitor in FIG. 2 and a first bus bar. FIG. [Figure 11]3 is a right side view illustrating the positional relationship between the lid member of the capacitor in FIG. 2 and the first bus bar. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] An embodiment of a capacitor according to the present invention will be described in detail with reference to FIGS.

[0023] The structure of a film capacitor 1, which is a capacitor according to this embodiment, will be described with reference to FIGS. 1 to 11. In FIGS. 1 to 11, 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 sides of the x-axis will be referred to as the rear and front, the positive and negative sides of the y-axis as the right and left, and the positive and negative sides of the z-axis 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 (right) or negative (left) side of the y-axis to the negative (left) or positive (right) side of the y-axis will be referred to as an "xz planar view," and a planar view of the negative (front) or positive (rear) side of the x-axis from the positive (rear) or negative (front) side of the x-axis will be referred to as a "yz planar view."

[0024] 1 to 3, film capacitor 1 includes metallized film capacitor elements 10 (in this embodiment, there are three metallized film capacitor elements, which will hereinafter be referred to as "capacitor elements" where appropriate), first and second bus bars 2 and 3, insulating member 4, case 5, sealing resin 6, and resin cover member 7. Reference numeral 8 denotes a tube through which a connection wire connected to a temperature sensor (described later) is inserted, and the connection wire is connected to connector 8a at the tip of tube 8.

[0025] 1, each of the plurality of capacitor elements 10 is configured to include an element body 11, a first end surface electrode 12 formed by spraying a metal such as zinc on one end surface (upper surface) of the element body 11, and a second end surface electrode 13 formed by spraying a metal such as zinc on the other end surface (lower surface) of the element body 11. Each capacitor element 10 corresponds to a "capacitor element" in the present invention, and the first end surface electrode 12 and the second end surface electrode 13 correspond to a "pair of end surface electrodes" in the present invention.

[0026] The element body 11 is formed by stacking two metallized films, each having aluminum vapor-deposited on a dielectric film, rolling or laminating the stacked metallized films, and pressing them into a flat shape. The element body 11 is not limited to the above-described configuration, which is formed from a metallized film having aluminum vapor-deposited on a dielectric film. For example, the element body 11 may be formed from a metallized film having other metals vapor-deposited thereon, such as zinc or magnesium, or from a metallized film having multiple of these metals vapor-deposited thereon, or from a metallized film having an alloy of these metals vapor-deposited thereon.

[0027] 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.

[0028] The first and second bus bars 2 and 3 are each made of a conductive material such as copper. The first bus bar 2 and the second bus bar 3 correspond to a "pair of bus bars" in the present invention.

[0029] 4 , the first bus bar 2 has a flat body 20 having a substantially rectangular outer shape in the x-y plane, which is electrically connected to the first end electrode 12 of the capacitor element 10 and close enough to be soldered thereto, and a flat raised portion 21 having a substantially rectangular outer shape in the y-z plane, which is raised in the z-axis direction from the end (rear end) on the positive x-axis side of the body 20, and a plurality of first external connection terminals 22 (three in this embodiment) extending substantially horizontally rearward (in the positive x-axis direction) from the upper end of the raised portion 21 opposite the body 20, bending downward and further extending rearward. Each first external connection terminal 22 has a through-portion 23 having a substantially circular shape in the x-y plane, which is used to fasten the first bus bar 2 to external wiring.

[0030] 5 , similar to the first busbar 2, the second busbar 3 has a flat, plate-like main body 30 with a substantially rectangular outer shape in the x-y plane, electrically connected to the second end-face electrode 13 of the capacitor element 10 and close enough to be soldered thereto, and a flat, plate-like raised portion 31 with a substantially rectangular outer shape in the y-z plane, which rises in the z-axis direction from the end (rear end) on the positive x-axis side of the main body 30. The second busbar 3 also has a plurality of (three in this embodiment) second external connection terminals 32 extending substantially horizontally rearward (in the positive x-axis direction) from the upper end of the raised portion 31 opposite the main body 20 side, bending downward and further extending rearward. Each second external connection terminal 32 has a substantially circular through-hole 33 formed therein, which is used to fasten the second busbar 3 to external wiring.

[0031] 1 , insulating member 4 has an L-shaped cross section and is disposed between first and second bus bars 2, 3, thereby insulating first bus bar 2 and second bus bar 3. More specifically, insulating member 4 includes: vertical insulating portion 41 having a substantially rectangular flat plate shape in the y-z plane view, which is disposed between rising portion 21 (not shown in FIG. 1 ) of first bus bar 2 and rising portion 31 of second bus bar 3; and horizontal insulating portion 42 which is integrally formed with vertical insulating portion 41 and extends in the positive direction of the x-axis (rearward) from the end of vertical insulating portion 41 on the positive side of the z-axis, and which is disposed between a horizontal portion of a front end (end on the negative side of the x-axis) of each first external connection terminal 22 and a horizontal portion of a front end (end on the negative side of the x-axis) of each second external connection terminal 32.

[0032] 1 to 4, case 5 has an opening on the positive side (upper) of the z-axis and a space forming a storage section inside, and can be made of 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. Case 5 corresponds to the "case" in this invention.

[0033] A portion of a capacitor unit (capacitor elements, a portion of first bus bar 2, a portion of second bus bar 3, and a portion of insulating member 4) having multiple capacitor elements 10, first and second bus bars 2 and 3, and insulating member 4 is accommodated in an accommodating portion within case 5. Furthermore, sealing resin 6 made of, for example, epoxy resin is filled into the accommodating portion of case 5 that accommodates the portion of the capacitor unit, thereby sealing the portion of the capacitor unit.

[0034] This sealing resin 6 is not limited to epoxy resin, and various insulating materials used as sealing resins for electronic components can be used. The sealing resin 6 is formed by being injected into the case 5 in a liquid state through the opening of the case and then curing. The sealing resin 6 corresponds to the "sealing resin" in this invention.

[0035] 2 and 3, a resin lid member 7 is disposed so as to cover a portion of the sealing resin 6. Like the case 5, the lid member 7 is formed from a material different from the sealing resin 6, such as organic materials including resins and plastics including polyphenylene sulfide (PPS) and polybutylene terephthalate (PBT), and inorganic materials including ceramics.

[0036] As shown particularly in Figure 6, the cover member 7 has a main body 70 that is approximately rectangular in the xy plane when viewed from the positive side (top) to the negative side (bottom) of the z axis, which is a direction perpendicular to the opening surface of the case 5, and the cover member 7 has a planar area larger than the total projected area of ​​the three capacitor elements 10 in the case 5, and is arranged in a position that covers all of the capacitor elements 10 when viewed from above.

[0037] The lid member 7 is formed with a plurality of cylindrical engaging portions 71 and recessed portions 72. Specifically, as shown in FIG. 6 , cylindrical engaging portions 71 are formed protruding in the positive direction of the z axis (upward) at seven locations: four locations at the four corners of the rectangle of the main body 70, and three locations at the front and rear central ends and intermediate positions of the two long sides of the rectangle in the y axis direction (left and right direction). The engaging portions 71 at the four corners and the engaging portion 71 at the front central end are formed so as to extend outside the substantially rectangular main body 70, and the case 5 is formed with positioning recesses 5a having an arc-shaped cross section that matches the outer shapes of the engaging portions 71 at the four corners and the engaging portion 71 at the front central end (FIG. 1). Simply by placing the lid member 7 on the sealing resin 6 filled in the case 5 while aligning it with each of the positioning recesses 5a, the lid member 7 can be fixed to the sealing resin 6 in a positioned state.

[0038] A cylindrical metal fastening portion 73 having an internal thread that can be fastened to an external thread on an external component (not shown) is embedded in each engaging portion 71 by insert molding, and the external component is fastened and engaged with the cover member 7 by screwing the external thread into all of the engaging portions 71 or any of the fastening portions 73, thereby fixing the external component to the cover member 7. At this time, one or more external components can be fixed to the cover member 7. Note that the fastening portion 73 is not limited to being embedded in the engaging portion 71 by insert molding, but may also be embedded by press fitting.

[0039] As shown in Figures 7 and 8, the buried portions 72 have a cylindrical shape and are integrally formed below each of the seven engaging portions 71, protruding downward. When the lid member 7 placed on the sealing resin 6 before hardening is pushed into the sealing resin 6, each buried portion 72 becomes buried in the sealing resin 6, and when the sealing resin 6 hardens, the lid member 7 is firmly fixed to the sealing resin 6.

[0040] 9, the film capacitor 1 is provided with a sensor that detects the state of the capacitor 1, for example, a temperature sensor S that detects the temperature of the film capacitor 1, and the temperature sensor S is arranged close to the first bus bar 2 and is housed together with the capacitor unit in a housing section within the case 5. The temperature sensor S is connected to one end of a connecting line C made of, for example, a flexible flat cable, which is on the y-axis positive side (right), while the other end of the connecting line C, which is on the y-axis negative side (left), is inserted into a tube 8 and led out of the housing section within the case 5, and is connected to an external circuit (not shown) via a connector 8a.

[0041] 8, a guide portion 74 is formed on the surface (lower surface) of the cover member 7 facing the sealing resin 6 to guide the connection wire C out of the case 5. As shown in the figure, the guide portion 74 is configured by a pair of generally L-shaped guide walls 74a that protrude downward and are integrally formed from the end (rear end) on the x-axis positive side of the lower surface of the cover member 7 to the end (right end) on the y-axis positive side, and the connection wire C is guided by being inserted into a groove between the two guide walls 74a.

[0042] Here, the other end of the connection line C guided by the guide portion 74, that is, the end on the y-axis positive side (right end), is supported from below by a U-shaped support portion 74b provided at the right front end of the underside of the main body portion 70 of the cover member 7, and the temperature sensor S at the end of the support portion 74b is held inserted in a holding portion 74c that protrudes downward and is integrally formed at the right front end of the underside of the main body portion 70. Note that a notch is formed in the main body portion 70 above the support portion 74b, so that the routing status of the right end of the connection line C can be visually observed from above.

[0043] Holding portion 74c is composed of front and rear walls, a right side wall, and a bottom wall facing sealing resin 6, which has a semi-elliptical notch cut out internally (see FIG. 8), and temperature sensor S is inserted into holding portion 74c from the open left side surface, and temperature sensor S detects the temperature of first bus bar 2 located below via the notch formed in the bottom wall of holding portion 74c. At this time, the vertical dimension of holding portion 74c is set so that the lower surface of the bottom wall of holding portion 74c, which is the end surface facing sealing resin 6, abuts against first bus bar 2 located on the upper surface, which is the opening surface of case 5, thereby positioning temperature sensor S at a predetermined distance from capacitor element 10.

[0044] 10 and 11, the height T, which is the vertical dimension of the retaining portion 74c, is set so that when the buried portion 72 of the cover member 7 is buried in the sealing resin 6, the lower surface of the retaining portion 74c abuts against the upper surface of the first bus bar 2, thereby positioning the temperature sensor S held by the retaining portion 74c at a predetermined position above the upper surface of the first bus bar 2. Here, the guide portion 74 is buried in the sealing resin 6 in the same way as the buried portion 72, fixing the cover member 7 to the sealing resin 6, and at the same time, the lower surface of the retaining portion 74c abuts against the upper surface of the first bus bar 2, positioning the temperature sensor S.

[0045] In addition, the other end of the connection line C guided by the guide portion 74, that is, the end portion (left end portion) on the negative side of the y-axis, is bent approximately 90 degrees in the positive direction of the z-axis (upward) in a rectangular notch 74d formed in the left rear end portion of the main body portion 70 of the cover member 7 and inserted into the tube 8, and its tip is connected to the connector 8a.

[0046] In this way, the lid member 7 covers a portion of the sealing resin 6 exposed on the open surface side of the case 5, and by positioning the lid member 7 so that the planar area of ​​the lid member 7 is larger than the projected area of ​​all of the capacitor elements 10 when viewed from a direction perpendicular to the open surface of the case 5 and by placing the lid member 7 in a position that covers all of the capacitor elements 10, the lid member 7 prevents moisture from entering the capacitor elements 10. A plurality of engaging portions 71 with fastening portions 73 inserted by insert molding are formed on the surface of the lid member 7 opposite the surface facing the sealing resin 6, and an external component is fastened by engaging with the fastening portions 73 of the engaging portions 71 to fix the external component to the lid member 7.

[0047] Therefore, according to the above-described embodiment, the lid member 7 can be positioned relative to the sealing resin 6 by fixing the lid member 7 in a state where it is overlapped on the sealing resin 6. Furthermore, the lid member 7 can prevent moisture from penetrating into the sealing resin 6, thereby improving the moisture resistance of the film capacitor 1. Furthermore, when an external component is to be placed in the empty space on the side opposite to the surface of the lid member 7 that faces the sealing resin 6, the external component can be stably fixed to the engaging portion 71 of the lid member 7, and the external component can be easily attached to the film capacitor 1 in the space above the film capacitor.

[0048] Furthermore, by covering the six peripheral surfaces of capacitor element 10 with sealing resin 6 and further covering a portion of sealing resin 6 with lid member 7, even if noise is generated in capacitor 1, the noise is significantly attenuated as it passes through both sealing resin 6 and lid member 7, thereby effectively reducing the noise generated in film capacitor 1.

[0049] Furthermore, since the buried portion 72 that is buried in the sealing resin 6 is integrally formed by protruding downward from the engaging portion 71 of the lid member 7, the lid member 7 with the external component fixed thereto can be firmly fixed to the sealing resin 6.

[0050] Furthermore, by insert-molding the metal fastening portion 73 into the engaging portion 71 of the cover member 7, the fastening portion that engages with the external component can be formed in advance when the cover member is manufactured (molded).

[0051] In addition, in this embodiment, PPS is used for the lid member 7 and epoxy resin is used for the sealing resin, but by using a material for the lid member 7 that has better heat dissipation properties than the sealing resin 6, the heat generated in the capacitor 1 can be efficiently dissipated to the outside via the lid member 7, making it possible to provide a capacitor 1 with excellent heat dissipation properties.

[0052] The present invention is not limited to the above-described configuration, and various design modifications can be made within the scope of the claims.

[0053] For example, in the above-described embodiment, in order to improve the moisture resistance of the film capacitor 1, the cover member 7 covers a portion of the sealing resin 6 exposed on the opening side of the case 5, but it is also possible to cover the entire sealing resin 6 exposed on the opening side of the case 5.

[0054] In the above embodiment, the engaging portions 71 and the buried portions 72 formed on the cover member 7 have been described as being cylindrical and columnar, respectively, but the engaging portions 71 and the buried portions 72 may each have a polygonal cross section in the xy plane. Furthermore, the number of engaging portions 71 and buried portions 72 is not limited to seven as described above, and may be one as long as it is possible to fix an external component.

[0055] In the above embodiment, the metal fastening portion 73 is insert-molded to engage an external component with the engaging portion 71, but it may be press-fitted after molding the engaging portion 71. Furthermore, the fastening portion 73 is not limited to being made of metal.

[0056] Furthermore, in addition to providing the fastening portion 73, an engagement structure consisting of, for example, a combination of a claw and a locking device that locks the claw, may be provided on the engagement portion 71 and the external part to engage and fix the external part to the engagement portion 71.

[0057] Furthermore, the shape of the guide portion 74 is not limited to the above-described substantially L-shape, but may be any shape that corresponds to the routing path of the connection wire C.

[0058] Furthermore, in the above embodiment, the sensor is a temperature sensor S, but the sensor is not limited to a temperature sensor and may be a voltage sensor or a current sensor.

[0059] The present invention is widely applicable to capacitors in which a bus bar is electrically connected to each of a pair of end surface electrodes of a capacitor element, and the capacitor element and a portion of the pair of bus bars are housed in a case and sealed with sealing resin. [Explanation of symbols]

[0060] 1...Film capacitor 2...First busbar 3...Second busbar 5. Case 6...Sealing resin 7...Cover member 71 ...Engagement part 72 … buried part 73 ... Fastening part

Claims

1. A capacitor comprising: a capacitor element having a pair of end surface electrodes; a first bus bar and a second bus bar electrically connected to the pair of end surface electrodes, respectively; and a case having an opening on one side and an accommodation portion therein, wherein the inside of the case is sealed with a sealing resin with the capacitor element and a portion of the pair of bus bars accommodated in the accommodation portion, a cover member that covers at least a portion of the sealing resin exposed on an opening side of the case; The cover member is The sealing resin is positioned relative to the sealing resin, a capacitor having an engaging portion formed on a surface opposite to the surface facing the sealing resin, the engaging portion engaging with an external component to fix the external component to the lid member;

2. The cover member is 2. The capacitor according to claim 1, further comprising an embedded portion that is embedded in the sealing resin to fix the lid member to the sealing resin.

3. The cover member is The capacitor according to claim 1 or 2, characterized in that it has a planar area larger than the projected area of ​​the capacitor element as viewed from a direction perpendicular to the opening surface, and is arranged in a position that covers the capacitor element as viewed from a direction perpendicular to the opening surface.

4. The embedded portion of the lid member is 3. The capacitor according to claim 2, wherein the capacitor is formed so as to protrude from the opposing surface toward the sealing resin.

5. 2. The capacitor according to claim 1, wherein a metal fastening portion capable of fastening to the external component is insert-molded into the engaging portion.

6. 2. The capacitor according to claim 1, wherein the lid member is made of a material that has a better heat dissipation property than the sealing resin.

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