Capacitor

Abstract

To achieve stable routing of connecting wires connected to a sensor.SOLUTION: There is provided a capacitor in which a part of a sealing resin exposed on the opening surface side of a case is covered by a lid member 7 that is positioned relative to the sealing resin, and, in a state where a capacitor element, a part of first and second bus bars, and a sensor are housed in a housing part of the case, connecting wires connected to the sensor is led out to the outside of the housing part while the connecting wires are guided by a guide part 74 formed on a side, of the lid member 7, opposite the surface facing the sealing resin.SELECTED DRAWING: Figure 8

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, a synthetic resin plate is placed on the exposed surface of the sealing resin, covering the entire exposed surface. Therefore, if a sensor such as a temperature sensor for detecting the state of the capacitor is to be installed, the sensor must be installed in a predetermined position before the synthetic resin plate is placed. Specifically, before the synthetic resin plate is placed, the sensor connected to the tip of the connection wire is fixed in a predetermined position, such as near the capacitor, using a fixing material such as heat-resistant tape. The sensor is then sealed with sealing resin and the connection wire is pulled out of the sealing resin. However, in this case, although the sensor itself is fixed with the fixing material, the connection wire is routed within the sealing resin and then led out of the sealing resin. As a result, the connection wire cannot be stably routed in a predetermined position, which could lead to unexpected problems associated with the routing of the connection wire, such as affecting the detection results.

[0007] The present invention has been made in view of the above-mentioned problems, and has an object to enable stable routing of connection wires connected to sensors. [Means for solving the problem]

[0008] In order to achieve the above object, a capacitor according to the present invention includes 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 accommodation section inside, wherein 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 section, the capacitor further includes a lid member that covers at least a portion of the sealing resin exposed on the open face of the case, a sensor that is accommodated in the accommodation section together with the capacitor element and a portion of the pair of bus bars and detects a state of the capacitor, and a connection wire having one end connected to the sensor and the other end led out of the accommodation section, the lid member having a guide portion formed on the surface opposite the sealing resin that guides the connection wire while leading it out of the accommodation section.

[0009] With this configuration, at least a portion of the sealing resin exposed on the open side of the case is covered with a lid member that is positioned relative to the sealing resin, the capacitor element, a portion of the pair of bus bars, and the sensor are housed in the housing portion of the case, and a guide portion formed on the surface of the lid member facing the sealing resin guides the connecting wire connected to the sensor out of the housing portion, allowing the connecting wire to be stably routed.As a result, unexpected problems caused by differences in the routing of the connecting wire are prevented, and the state of the capacitor can be stably and accurately detected by the sensor.

[0010] The cover member may further include a holding portion formed on the opposing surface side for holding the sensor.

[0011] According to this configuration, by holding the sensor with the holding portion, the sensor can be easily positioned, and the holding portion can hold the sensor without causing it to shift position, making it possible for the sensor to stably detect the state of the capacitor.

[0012] It is also preferable that the end face of the holding portion on the opposing surface abuts against the bus bar located on the opening surface side of the case, of the first bus bar and the second bus bar, so that the sensor is positioned at a predetermined distance from the capacitor element.

[0013] With this configuration, the end face on the opposing side of the holding portion abuts against the bus bar located on the opening side of the case, thereby positioning the sensor at a predetermined distance from the capacitor element, and thereby enabling the sensor to be held at a predetermined position (a predetermined distance from the capacitor element) with high precision.

[0014] In addition, the guide portion has a pair of guide walls protruding from the opposing surface toward the sealing resin, and the connecting wire is inserted between the guide walls to position the connecting wire relative to the cover member, and the guide walls are embedded in the sealing resin to fix the cover member to the sealing resin.

[0015] According to this configuration, a pair of guide walls protruding toward the sealing resin are provided in the guide section, so that the connection wire can be easily positioned relative to the cover member by inserting the connection wire between the guide walls, and further, by embedding the guide walls in the sealing resin, the cover member can be firmly fixed to the sealing resin. [Effects of the Invention]

[0016] According to the present invention, stable routing of the connection wire connected to the sensor is possible. [Brief explanation of the drawings]

[0017] [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

[0018] An embodiment of a capacitor according to the present invention will be described in detail with reference to FIGS.

[0019] 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. In the following, 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. In the following, 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."

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] A metal columnar 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] In addition, the other end of the connection line C guided by the guide portion 74, that is, the end portion on the positive side of the y-axis (right end portion), 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.

[0042] Therefore, according to the above-described embodiment, a portion of the sealing resin 6 exposed on the opening side of the case 5 is covered with the lid member 7 that is positioned with respect to the sealing resin 6, and the capacitor element 10, portions of the first and second bus bars 2 and 3, and the temperature sensor S are accommodated in an accommodation section within the case 5, and the connecting wire C connected to the temperature sensor S is guided and led out of the accommodation section by the guide portion 74 formed on the surface of the lid member 7 that faces the sealing resin 6, so that the connecting wire C connected to the temperature sensor S can be stably routed. As a result, unexpected problems caused by differences in the routing of the connecting wires can be prevented, and the temperature state of the capacitor can be stably and accurately detected by the temperature sensor S.

[0043] At this time, the connection wire C can be easily positioned relative to the cover member 7 by inserting it between the two guide walls 74a protruding toward the sealing resin 6, and further, the anchor effect of embedding the guide walls 74a in the sealing resin 6 allows the cover member 7 to be firmly fixed to the sealing resin 6.

[0044] Furthermore, since a holding portion 74c is formed on the surface of the cover member 7 facing the sealing resin 6, the temperature sensor S is held in the holding portion 74c, which makes it easy to position the temperature sensor S, and the holding portion 74c makes it possible to hold the temperature sensor S without it shifting position, thereby enabling stable temperature detection of the film capacitor 1 by the temperature sensor S.

[0045] Furthermore, since the end face on the opposing side of the holding portion 74c abuts against the first bus bar 2 located on the opening side of the case 5, the temperature sensor is positioned at a predetermined distance from the capacitor element 10, and the temperature sensor S can be held at a predetermined position (a predetermined distance from the capacitor element 10) with high precision.

[0046] Furthermore, by covering the sealing resin 6 with a lid member 7 having a planar area larger than the projected area of ​​all capacitor elements 10 onto the xy plane, it is possible to prevent moisture from penetrating into capacitor elements 10 through the sealing resin 6, thereby improving the moisture resistance of film capacitor 1. Furthermore, by covering all six sides of capacitor element 10 with sealing resin 6 and covering part of the sealing resin 6 with lid member 7, even if noise is generated in capacitor 1, the noise is significantly attenuated as it passes through the two resins, sealing resin 6 and lid member 7, thereby effectively reducing the noise generated in film capacitor 1.

[0047] Furthermore, the buried portion 72 that is buried in the sealing resin 6 is formed integrally with the engaging portion 71 of the lid member 7 so as to protrude downward, and the buried portion 72 is buried in the sealing resin 6. Therefore, the lid member 7 with the external component fixed thereto can be firmly fixed to the sealing resin 6 by the anchor effect of the buried portion 72 in addition to the anchor effect of the guide portion 74.

[0048] 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.

[0049] The present invention is not limited to the above-described configuration, and various design modifications can be made within the scope of the claims.

[0050] For example, in the above embodiment, in order to improve the moisture resistance of the film capacitor 1, the lid member 7 covers a portion of the sealing resin 6 exposed on the opening side of the case 5, but it may also cover the entire sealing resin 6 exposed on the opening side of the case 5. Furthermore, the lid member 7 is not limited to being made of resin.

[0051] 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.

[0052] 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.

[0053] 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]

[0054] 1...Film capacitor 2...First busbar 3...Second busbar 5. Case 6...Sealing resin 7...Cover member 74...Guide section 74a ... Guide wall 74c...Holding 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, the case being 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 the opening side of the case; a sensor that is accommodated in the accommodation portion together with the capacitor element and a portion of the pair of bus bars and that detects a state of the capacitor; a connection line whose one end is connected to the sensor and whose other end is led out of the storage section; Equipped with The lid member has a guide portion formed on the surface facing the sealing resin, which guides the connection wire and leads the connection wire out of the accommodating portion.

2. The cover member is 2. The capacitor according to claim 1, further comprising a holding portion formed on the opposing surface for holding the sensor.

3. The capacitor according to claim 2, characterized in that the end face of the holding portion on the opposing surface side abuts against one of the first bus bar and the second bus bar that is located on the opening surface side of the case, thereby positioning the sensor at a predetermined distance from the capacitor element.

4. The capacitor according to any one of claims 1 to 3, characterized in that the guide portion has a pair of guide walls protruding from the opposing surface toward the sealing resin, and the connection wire is inserted between the guide walls to position the connection wire relative to the cover member, and the guide walls are embedded in the sealing resin to fix the cover member to the sealing resin.

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