JP2002367857A - Film capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film capacitor for high frequency, large current, and large voltage that can efficiently radiate the heat generated by a capacitor element, appropriately shields heat to the capacitor element from the outside, reduces self heat generation, and reduces heat deterioration and improves life. SOLUTION: A capacitor element 10 is housed by plus-side terminal plate 11 for external extraction and a minus, and a minus-side terminal plate 12 for extraction and the plus-side terminal plate 11 for external extraction are overlapped via an insulating film 59. Connection pieces 34 and 35 are joined to the plus-side terminal plate 11 for external extraction, and connection pieces 51 and 52 of the minus-side terminal plate 11 for external extraction are connected to the other electrode section 22. The capacitor element 10 and both the plus-side and minus-side terminal plates 11 and 12 for external extraction are accommodated in a resin case 13 and are sealed by an insulating resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film capacitor, and more particularly, to a film capacitor of an electrode protruding type which is disposed in a resin case and sealed with a resin, has excellent heat radiation and heat shielding effects, and reduces self-heating. And a film capacitor.

[0002]

2. Description of the Related Art A dry metallized film capacitor disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-277377 is known as a film capacitor capable of efficiently radiating heat generated by a capacitor element due to energization.
In this film capacitor, a pair of metallized films are superimposed and wound, a plurality of capacitor elements serving as electrodes are sprayed with metal on the winding end face, and a plurality of capacitor elements are connected in parallel, and a heat sink is interposed between the capacitor elements. The capacitor body is inserted into the capacitor body, the capacitor body is housed in a metal case, sealed with an insulating resin, and an external lead-out terminal and one end of a heat radiating plate are projected outside the case.

In the dry type high-voltage phase-advancing capacitor described in Japanese Utility Model Application Laid-Open No. 5-43533, insulating resin potting capacitors are arranged in two rows, and a metal plate or an insulating material having a high thermal conductivity is provided between these capacitor groups. A radiator plate made of a plate is interposed, and a part of the radiator plate is brought into contact with the inner surface of the outer metal case so as to be able to conduct heat.

[0004] In addition, an electrolytic capacitor in which a connecting plate connected to a capacitor element also serves as a heat sink or a lead terminal connected to the capacitor element and a heat sink are integrated to improve the heat dissipation effect. (Japanese Patent Laid-Open No. 6
JP-A-106361, JP-A-11-219854, etc.) are also known.

[0005]

As described above, a heat radiating plate is conventionally used to efficiently radiate heat generated by a capacitor element. However, most of the conventional capacitors are aimed at improving the heat dissipation effect.
No measures have been taken to reduce the self-heating of the capacitor itself or to reduce the external thermal effect on the capacitor element. In particular, in the case of an insulated gate bipolar transistor (hereinafter, referred to as an IGBT) used as a switching element in recent years or a capacitor used in a protection circuit (snubber circuit) for surge voltage during switching of a MOSFET module, a high frequency, large Since a high current and a large voltage are required, it is not enough to enhance the heat radiation effect, and a device that shields heat from the IGBT and reduces self-heating is required.

[0006] The present invention has been made to address the above-mentioned conventional problems and demands.
The heat of the capacitor element can be dissipated efficiently,
Also, it effectively blocks heat from the outside to the capacitor element,
Moreover, it is an object of the present invention to provide a film capacitor in which self-heating is reduced, thermal deterioration is reduced, and the life is improved.

[0007]

In order to achieve the above object, a first aspect of the present invention is to provide a positive and negative external lead-out terminal having a capacitor element integrally formed with an internal terminal part and an external terminal part in a resin case. In a film capacitor in which the external terminal portion of each of the external lead-out terminal plates is housed and resin-sealed and the external terminal portion of each of the external lead-out terminal plates is projected outward of the case, At least one of them is formed in a shape including the capacitor element, and the internal terminal portion of each of the external lead-out terminal plates is joined to each electrode portion of the capacitor element. In the present invention, since the external lead-out terminal plate surrounds both the peripheral surface of the capacitor element and the electrode portion, the surface area is large, and the heat of the capacitor element is efficiently radiated,
Also serves as a heat sink. In addition, it has a function as a heat shield in addition to a function as a heat sink. That is, even if heat outside the capacitor is transmitted to the inside through the resin case, the external lead-out terminal plate containing the capacitor element receives the heat and radiates heat to the outside without being transmitted to the capacitor element. Therefore, heat from outside is shielded, and the thermal effect on the capacitor element is reduced.

According to a second aspect of the present invention, a capacitor element is housed in a resin case together with a positive side and a negative side external lead-out terminal plate integrally having an internal terminal portion and an external terminal portion, and sealed with a resin. In the film capacitor in which the external terminal portion of the lead-out terminal plate protrudes outward from the case, the internal terminal portion of the positive-side external lead-out terminal plate is formed in a shape that covers a surface of one electrode portion of the capacitor element. A tongue-shaped connecting piece having a small heat capacity is integrally extended at the opening edge of the opening, and the connecting piece is joined to the one electrode part. The opening is opened to the edge of the plus-side external lead-out terminal plate through a slit, and the external terminals are integrally extended on both sides of the slit. In the present invention, since the terminal circuit is formed by forming the opening and the slit, the impedance between the external terminals is reduced. Also, generation of eddy current is reduced. Therefore, self-heating of the capacitor can be reduced.

According to a third aspect of the present invention, in the first or second aspect, a plate portion which is opposed to the plus side external lead-out terminal plate and the minus side external lead-out terminal plate via an insulating member is provided. And the resin case is fixed to the heat sink such that the negative-side external lead-out terminal plate is closer to the heat sink than the positive-side external lead-out terminal plate. In the present invention, the heat of the positive side external lead-out terminal plate is released to the heat sink via the insulating member and the negative side external lead-out terminal plate, and the heat sink efficiently radiates heat.

In a fourth aspect based on the first, second or third aspect, the rear edge of at least one of the positive side external lead-out terminal plate and the negative side external lead-out terminal plate is provided. Positioning projections are integrally provided on the portion, and these positioning projections are respectively brought into contact with inner corners of the resin case. In this invention, the terminal plate is positioned by the inner corner of the resin case. The inner corner portion of the resin case has the highest strength because the three plate portions orthogonal to each other are joined, and the warpage due to shrinkage of the resin after molding is small, so that the terminal plate is accurately positioned. be able to.

In a fifth aspect based on the second aspect, the connecting piece of the positive side external lead-out terminal plate is formed in a shape having a small heat capacity. In the present invention, since the heat capacity of the connection piece is small, when the connection piece is soldered to the electrode portion of the capacitor element and joined by welding or the like, heat is quickly transmitted to the electrode portion. After the joining operation is completed, the temperature is rapidly lowered, and the thermal effect on the capacitor element is reduced.

In a sixth aspect based on the first, second, third, fourth, or fifth aspect, the internal terminal portion of the positive-side external lead-out terminal plate covers one side surface of the capacitor element. A plate portion is extended, and the plate portion has an opening that opens to an edge through a slit. In the present invention, the generation of the eddy current is reduced by forming the opening and the slit. Therefore, self-heating due to eddy current loss can be reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a plan view showing a part of an embodiment in which a film capacitor according to the present invention is used in an snubber circuit of an IGBT, FIG. 2 is a front view of an input-side film capacitor, and FIG. FIG. 4 is an exploded perspective view of the film capacitor, FIG. 5 is a front view of the output-side film capacitor, FIG. 6 is a cross-sectional view of the film capacitor, and FIG. 7 is an exploded perspective view of the film capacitor. .

In FIG. 1, reference numeral 1 denotes a case body that opens upward, and 2 denotes a cover that covers an opening of the case body 1, and these constitute a heat sink 3 that houses the IGBT 4. Reference numeral 5 denotes an input side film capacitor used in the snubber circuit of the IGBT 4, and 6 denotes an output side film capacitor. The heat sink 3 is maintained at a required temperature (for example, 65 ° C.) by water cooling since the IGBT 4 and the input and output side film capacitors 5 and 6 each constitute a heating element. The IGBT 4 and the input and output film capacitors 5, 6 are positioned close to each other on the inner bottom surface of the case body 1, fixed by a plurality of setscrews 7, and electrically connected by connection terminals 8, 9, respectively. It is connected to the. Hereinafter, the input and output film capacitors 5 and 6 will be described in more detail.

2 to 4, an input-side film capacitor 5 includes a capacitor element 10 and two terminal plates bonded to the respective electrode portions 21 and 22 of the capacitor element 10, that is, a positive side electrode and a negative side electrode. External drawing terminal plates 11 and 12 and these external drawing terminal plates 1
A resin case 13 (hereinafter, referred to as a resin case) for accommodating the capacitor elements 10, 12 and the capacitor element 10, an insulating filling resin 14 for resin-sealing the capacitor element 10 and the external lead terminal plates 11, 12. It is composed of

The capacitor element 10 is made of two metallized films, that is, an extremely thin strip-shaped insulating film (usually a polyester film) in which aluminum or the like is vapor-deposited on one surface to form metal electrodes (shaded portions in FIG. 4) 16. ) 17 are stacked and wound a predetermined number of times to form a capacitor body 10a.
A so-called vapor-deposited-electrode-type capacitor element having the electrode portions 21 and 22 on both end surfaces in the axial direction of 0a is used. Each of the electrode portions 21 and 22 forms a metallikon electrode by being formed by spraying a metal or alloy such as copper, zinc, tin, and solder. The insulating film 17 is a metal electrode 16
The metal electrode 16 is vapor-deposited along one side edge in the width direction to form a non-deposited portion (margin portion) 23 on the other side edge side. Such an insulating film 1
7 is wound by being overlapped and wound so that the margin portions 23 are alternately left and right opposite to each other.
Electrical connection between the metal electrode 22 and the metal electrode 16 is enabled.
In the vicinity of the winding end of the insulating film 17, the metal electrode 16 is removed by a burn-off process, and heat-sealed. Then, the insulating film 17 is formed by flattening the capacitor main body 10a into a desired shape and the electrode portions 21 and 22 are formed.
Is provided, heat treatment is performed at a predetermined temperature (100 to 150 ° C.) for a certain period of time (about 3 to 10 hours) in a heating step for stabilizing the capacitance, thereby contracting.

In this embodiment, as shown in FIG. 4, the capacitor element 10 has a length L (dimension in the long axis direction), a width W (dimension in the short axis direction), and a height H (electrode portion). 21,
Although an example in which the shape is flattened into an elliptical columnar body (dimension between 22) has been described, it is needless to say that a columnar shape that does not flatten may be used.

The positive-side external lead-out terminal plate 11 is made of a copper plate (C1100 1 / 4H) and has a shape including the capacitor element 10 by press working, that is, the periphery of the capacitor element 10 (in the present embodiment, the upper side). By forming it in a shape surrounding the lower surface and a part of the back surface and the front surface), the function as a heat radiating plate and the function as a heat shielding plate are both provided. For this reason, the plus-side external lead-out terminal plate 11 is configured such that the upper and lower ends of the rectangular plate-shaped internal terminal portion 11A and the upper and lower ends of the internal terminal portion 11A are slightly opposite to each other. About 9 forward
It is composed of first and second bent pieces 11B and 11C bent at an angle of 0 °, and an external terminal 11D extending upward from the tip of the first bent piece 11B.

The internal terminal portion 11A has a rectangular opening 33 elongated in the longitudinal direction at the center, and tongue-like connecting pieces 34, 35 at the center in the width direction on both left and right edges of the opening 33.
Are integrally extended so as to face each other. The distal ends of these connecting pieces 34 and 35 are formed under pressure so that the plate thickness gradually decreases in order to reduce the heat capacity.
The capacitor element 10 is joined to one of the electrode portions 21 by welding (or soldering). A small rectangular positioning notch 37 is provided at one corner of the lower edge of the internal terminal portion 11A where the first bent piece 11B is continuously provided.
Are formed. The shape for reducing the heat capacity of the connection pieces 34 and 35 is not limited to the shape that reduces the plate thickness, but may be a shape that reduces the width or a shape that reduces both the width and the plate thickness.

The first bent piece 11B is formed to be slightly longer than the internal terminal portion 11A, a right edge 29a thereof is flush with a right edge 28a of the internal terminal portion 11A, and a left edge 29b is formed inside the internal terminal portion 11A. It protrudes laterally from the left edge 28b of 11A. Further, a slit 38 is formed substantially at the center in the width direction of the first bent piece 11B. The slit 38 is formed in an L-shape so as to extend to the first bent piece 11B and the internal terminal portion 11A, so that the opening 33 is formed at the leading edge 29c of the first bent piece 11B. Open to the public.

The second bent piece 11C has the same length as the internal terminal portion 11A, has the same forward projecting dimension (bending dimension) over its entire length, and is electrically connected to the electrode section 22. The electrode portions 21 and 22 in order to prevent
Is set lower than the height H. 2nd bent piece 11C
A rectangular opening 41 long in the width direction and a slit 42 for opening the opening 41 to the front end edge 30a of the second bent piece 11C are formed in the center of the base end in the width direction.

The external terminal portion 11D has two terminal portions 31A and 31B which are formed by bending upward at both sides of the slit 38 at the front edge of the first bent piece 11B with a predetermined interval therebetween. A lead wire 46 and a plate-like connection terminal 8 are connected to these terminal portions 31A and 31B, respectively, and a required current (for example, 50 A, 100
KZ). Each terminal 3
1A and 31B are bent in L-shape, respectively, so that vertical plate portions 31A-1 and 31B-1 opposed to the internal terminal portion 11A with the capacitor element 10 interposed therebetween.
And plate portions 31A-2 and 31B-2 which are bent substantially perpendicularly forward from the front ends of the respective plate portions 31A-1 and 31B-1. Therefore, the positive-side external lead-out terminal plate 11 constitutes a two-terminal type terminal plate. Each plate part 31A
-2 and 31B-2 have screw mounting holes 47 into which fixing screws (not shown) for connecting the connection terminals 8 and the lead wires 46 are screwed. A piece 48 is bent downward. Each terminal 31
The distance between the internal terminals 11A and the plate portions 31A-1, 31B-1 of the electrodes A, 31B is determined by the distance between the electrode 22 and the terminals 31A-1,
The height is set to be larger than the height H of the capacitor element 10 in order to prevent electrical connection with 31B-1. In addition,
The inner terminal portion 11A (excluding the connection pieces 34 and 35), the first,
Second bent pieces 11B, 11C and plate portions 31A-1, 31
The inner surface of B-1 is covered with an insulating film.

The negative-side external lead-out terminal plate 12 includes:
Copper plate (C
1100 1 / 4H), and has a function as a heat sink and a function as a heat shield by being formed into a substantially "Z" shape in side view by press working. For this reason, the negative-side external lead-out terminal plate 12 includes a rectangular plate-shaped internal terminal portion 12A, a bent piece 12B that is bent substantially at a right angle above the front end of the internal terminal portion 12A, and a bent piece 12B. And an elongate plate-like external terminal portion 12C which is bent at a substantially right angle forward from the upper end of the external terminal portion. The internal terminal portion 12A is provided with the positive side external lead-out terminal plate 11.
The length of the first bent piece 11B is substantially the same as the length of the first bent piece 11B, but the width thereof is larger than that of the first bent piece 11B, and positioning projections 50 are provided on both sides of the rear end. Two tongue-shaped connecting pieces 5 are provided on the front end side of the internal terminal portion 12A.
Reference numerals 1 and 52 are bent upward to face the rear surface of the first bent piece 12B. One connecting piece 51 is provided at an intermediate portion of the internal terminal portion 12A. For this reason, a rectangular opening 54 is formed in the longitudinally middle portion of the internal terminal portion 12A. The other connecting piece 52
Is longer than the one connection piece 51 and is provided on one side edge of the internal terminal portion 12A. Therefore, a rectangular concave portion 55 is formed on one side edge of the internal terminal portion 12A. The tip of each of the connection pieces 51 and 52 has the same shape as the connection pieces 34 and 35 of the terminal board 11 for plus-side external drawing, as described above.
In order to reduce the heat capacity, the pressure is formed so that the plate thickness gradually decreases toward the tip. In this case, needless to say, the width may be reduced, or both the width and the plate thickness may be reduced.

The external terminal portion 12C has two screw mounting holes 56 and one positioning bent piece 57. The two screw mounting holes 56 are formed apart from each other in the longitudinal direction of the external terminal portion 12C. Folding piece for positioning 5
Reference numeral 7 is formed by bending one side edge of the external terminal portion 12C to the surface side at a substantially right angle.

[0025] Such a terminal plate 1 for external pull-out on the minus side.
Reference numeral 2 denotes a plus-side external lead-out terminal which is superimposed on a lower surface of the first bent piece 11B of the plus-side external lead-out terminal plate 11 via a thin insulating film 59 so that an upper surface of the internal terminal portion 12A is in close contact therewith. It is assembled to the plate 11. In this state, one connection piece 51 is connected to two terminal portions 31A,
31B, and the other connecting piece 52 is connected to the terminal 31A.
Is located outside. And the capacitor element 10
Is inserted between the first and second bent pieces 11B and 11C along the internal terminal portion 11A from the side of the positive-side external lead-out terminal plate 11, and one of the electrode portions 21 is connected to the positive-side external lead-out terminal. The connection pieces 34 and 35 of the plate 11 are welded or soldered 61A.
(FIG. 3), and the connection pieces 51, 52 of the negative-side external lead-out terminal plate 12 are joined to the other electrode portion 22 by welding or solder 61B (FIG. 3).

When the positive and negative external lead terminal plates 11 and 12 are attached to the capacitor element 10, the positioning projections 50 of the negative external lead terminal plate 12 are fixed to the positive external lead terminal plate. 11 protrudes rearward from the internal terminal portion 11A. Then, the capacitor element 10 to which the positive and negative external lead-out terminal plates 11 and 12 are attached is housed and positioned in the resin case 13, and is sealed by filling the insulating resin 14.

The resin case 13 is made of an epoxy resin or the like, and the plus and minus external lead-out terminal plates 11,
12 is formed in a rectangular box shape that is open to the front and is large enough to accommodate the capacitor element 10 to which it is attached, and is composed of a back plate 13a, a bottom plate 13b, an upper plate 13c, and left and right side plates 13d and 13e. , Facing each other 2
Positioning portions 60 for positioning the plus-side external lead-out terminal plate 11 are integrally protruded below the inner surfaces of the two side plates 13d and 13e. These positioning parts 6
Numeral 0 is a protruding strip extending in the depth direction of the resin case 13, and a predetermined gap is set between the resin case 13 and the bottom plate 13b. This gap is formed between the second bent piece 11B of the plus side external lead-out terminal plate 11 and the minus side external lead-out terminal plate 12.
Are set to allow insertion of the internal terminal portion 12A.

When assembling the capacitor element 10 into the resin case 13 together with the positive and negative external lead terminal plates 11 and 12, the negative external lead terminal plate 1
2 is housed along the inner surface of the bottom plate 13b, and the internal terminal portion 12A and the positive side external lead-out terminal plate 11 are accommodated.
Is positioned between the bottom plate 13b and the positioning portion 60. Capacitor element 10 in resin case 1
3, the distal end portion of the external terminal portion 11D of the plus side external lead-out terminal plate 11 and the external terminal portion 12C of the minus side external lead-out terminal plate 12 extend forward from the opening of the resin case 13. It protrudes. One of the two positioning portions 60 is inserted into the positioning notch portion 37 of the plus-side external lead-out terminal plate 11, and the other is the end of the second bent piece 11B opposite to the notch portion 37 side. Abuts the upper surface of the part. The two positioning protrusions 50 of the negative-side external lead-out terminal plate 12 are connected to the rear plate 13 of the resin case 13.
a, respectively. Accordingly, the internal terminal portion 11 </ b> A has the rear side plate 13.
It is assembled in a state separated from a. Then, the insulating resin 14 melted in this state is filled into the resin case 13 and solidified to form the capacitor element 10 and the resin case 1 of the external lead terminal plates 11 and 12 on the plus side and the minus side.
3 is completely sealed, and the input-side film capacitor 5 is completed. As the insulating resin 14, a thermosetting resin such as an epoxy resin or a polyurethane resin is used.

In FIGS. 1 and 2, the input side film capacitor 5 is mounted in the heat sink 3 by mounting the bottom plate 13b of the insulating case 13 on a predetermined capacitor mounting portion 1A on the inner bottom surface of the case 1. Then, the positioning bent piece 57 of the negative side external lead-out terminal plate 12 is moved to FIG.
The positioning plate 63 provided on the inner bottom surface of the case 1 as shown in FIG.
The external terminal 12C is fixed to the positioning plate 63 with two setscrews 7 and one terminal 31A of the positive side external lead-out terminal plate 11 is connected to the power source by the lead wire 46. Side, and the other terminal portion 31
B is connected to the IGBT 4 by a connection terminal 8.

In FIG. 5 to FIG. 7, the output side film capacitor 6 includes a capacitor element 70 and two terminal plates bonded to the respective electrode portions 76 and 77 of the capacitor element 70, ie, a plus side and a minus side. , A resin case 73 for accommodating the external lead terminal plates 71, 72 and the capacitor element 70, and a resin seal for the capacitor element 70 and the external lead terminal plates 71, 72. And an insulating resin 74 to be stopped.

The capacitor element 70 includes a capacitor body 70a formed by winding a metallized film in the same manner as the capacitor element 10 of the input-side film capacitor 5 described above, and copper ends on both ends in the axial direction of the capacitor body 70a. The electrode portions 76 and 77, which are formed by metal spraying metals such as zinc, tin, and solder, respectively, constitute a vapor deposition electrode type capacitor element. The capacitor element 70 was flattened into an elliptical columnar body having a length L0 (dimension in the long axis direction), a width W0 (dimension in the short axis direction), and a height H0 (dimension between the electrode portions 76 and 77). Although an example in which a material is used has been shown, it is a matter of course that a cylindrical shape which does not flatten may be used.

The positive-side external lead-out terminal plate 71 is made of a copper plate (C1100 1 / 4H), and is formed into a shape substantially enclosing the capacitor element 70 by press working, that is, a shape surrounding the periphery of the capacitor element 70. In this way, the front view shape is substantially U-shaped downward, and serves both as a heat radiating plate and a heat shielding plate. For this reason, the positive side external lead-out terminal plate 71 has a length L0 and a width W0 of the capacitor element 70.
A slightly larger rectangular plate-shaped internal terminal portion 71A, and first and second bent pieces 71B formed by bending both side edges of the internal terminal portion 71A downward at an angle of about 90 ° so as to face each other. , 71C and an external terminal 71D extending from the front end of the internal terminal 71A.

The internal terminal 71A is connected to the electrodes 76, 7
7 is formed of a rectangular plate sufficiently larger than the opening 7 and has an isosceles triangular opening 83 at the center, the top of which is a slit 83a.
To the front end of the internal terminal 71A. Further, on the two left and right slopes of the opening 83, tongue-shaped connecting pieces 84 are integrally extended so as to face each other. The distal ends of these connection pieces 84 are formed under pressure so that the plate thickness gradually decreases in order to reduce the heat capacity. However, the width or both the width and the plate thickness may be reduced. Further, positioning projections 87 are integrally provided on both sides of the rear end of the internal terminal 71A.

The first and second bent pieces 71B, 71C
Are formed to be the same size and shorter than the height H0 of the capacitor element 70 in order to prevent electrical connection with the electrode portion 77.

The external terminal portion 71D comprises two terminal portions 81A, 81B extending on both sides of the slit 83a at the front end of the internal terminal portion 71A, and these terminal portions 81A, 81B. Connection terminals 9 and 8
5 are connected to each other, and a required current (for example, 3 to 5
A, 100 KZ).
Therefore, the positive-side external lead-out terminal plate 71 forms a two-terminal type terminal plate. The terminal portions 81A and 81B
Is an inclined portion 81A bent obliquely downward at the base end.
-1, 81B-1, and the connection terminal 9,
A nut 91 is provided with a screw mounting hole into which a fixing screw for connecting the connector 85 is screwed. Further, the side edge of the terminal portion 81B opposite to the terminal portion 81A side is the third edge.
Are formed so as to protrude to the side of the bent piece 71C, and a positioning engaging concave portion 92 is formed at the base end thereof. Note that an insulating film is applied to the inner surface (except for the connection piece 84) of the positive side external lead-out terminal plate 71.

The negative-side external lead-out terminal plate 72 includes:
Similarly, it is made of a copper plate (C1100 1 / 4H) and has a shape in plan view by press working, which is the above-mentioned positive side external lead-out terminal plate 71
The slightly smaller front view shape is formed in a substantially upward U-shape, so that both the function as a heat radiating plate and the function as a heat shielding plate are provided. For this reason, the negative-side external lead-out terminal plate 72 includes a rectangular plate-shaped internal terminal portion 72A,
First and second bent pieces 72B and 72C which are bent upward at substantially right angles at both ends in the longitudinal direction of the internal terminal portion 72A;
A third bent piece 72D that is bent upward at a substantially right angle to the front end of the internal terminal part 72A, and an external terminal part 72E that is formed by bending the upper end of the third bent piece 72D forward by about 90 °. It is composed of

The internal terminal portion 72A has two tongue-like connecting pieces 95 formed by punching a U-shaped hole 96 near both ends in the longitudinal direction.
The distal ends of these connection pieces 95 are formed under pressure so that the plate thickness gradually decreases in order to reduce the heat capacity.
Further, positioning projections 98 are integrally provided on both sides of the rear end of the internal terminal 72A. These projections 98 project rearward from the first and second bent pieces 72B, 72C.

The first and second bent pieces 72B, 72C
Are formed shorter than the height H0 of the capacitor element 70 in order to prevent electrical contact with the electrode portion 76, and the first and second bent pieces 71B, 71C, these bent pieces 71B, 7B
1C with a thin insulating film 100 interposed therebetween.
A positioning notch 101 is formed at the base of the front edge of the second bent piece 72C.

The external terminal portion 72E has two screw mounting holes 104 and one positioning bent piece 105. The two screw mounting holes 104 are provided in the external terminal portion 72E.
Are formed apart from each other in the longitudinal direction. The positioning bending piece 105 is formed by bending one side edge of the external terminal portion 72E downward at a substantially right angle. One end of the external terminal portion 72E where the positioning bending piece 105 is provided protrudes laterally from the first bending piece 72B, and engages with the rear end edge of this protruding end. A recess 107 is formed.

The positive-side external lead-out terminal plate 71 and the negative-side external lead-out terminal plate 72 are connected to the capacitor element 7.
The inner surfaces of the internal terminal portions 71A and 72A of these terminal plates 71 and 72 are brought into close contact with the respective electrode portions 76 and 77 of the capacitor element 70 by connecting the connection pieces 84 and 95, respectively. Are joined to the surfaces of the electrode portions 76 and 77 by welding (or solder) 112a and 112b. Thereby, the positive side external lead-out terminal plate 7
1 and the negative-side external lead-out terminal plate 72 enclose the capacitor element 70 in a horizontal direction, and cover the outer periphery of both ends and the electrode parts 76 and 77, which form a semicircle in the axial direction of the capacitor element 70.

The resin case 73 is formed in a rectangular box shape whose front is opened with epoxy resin or the like, and is composed of a back plate 73a, a bottom plate 73b, an upper plate 73c, and left and right side plates 73d and 73e. The negative side terminal plate 7 for external drawing is provided on the inner surfaces of the bottom plate 73b and the upper plate 73c.
Positioning portions 110 for positioning the 2 and the plus-side external lead-out terminal plate 71 respectively are integrally provided so as to protrude. The positioning portion 110 is formed of a ridge that is long in the depth direction of the resin case 73. The positioning portion 110 provided on the bottom plate 73b and the positioning portion 110 provided on the upper plate 73c are slightly opposed to each other, and the facing interval is for the external drawing on the plus side and the minus side including the capacitor element 70. The terminal plates 71 and 72 are set to dimensions that can be fitted with a slight gap. In other words, the positive and negative external lead-out terminal plates 71 and 72 are inserted between the positioning portion 110 of the bottom plate 73b and the positioning portion 110 of the upper plate 73c.

When the capacitor element 70 is assembled into the resin case 73 together with the positive and negative external lead terminal plates 71 and 72, the internal terminal portions 71A of the positive and negative external lead terminal plates 71 and 72 are provided. , 72A are stored along the positioning portion 110, and the positioning projections 8
7, 98 are brought into contact with the respective corners of the back plate 73a. When the capacitor element 70 is housed in the resin case 73 and the positioning projections 87, 98 abut against the back plate 73a, the positioning recesses 92, 107 of the positive and negative external lead-out terminal plates 71, 72 become side plates. The front ends of the external terminal portions 71D and the external terminals 72E protrude forward from the openings of the resin case 73 by contacting the front edges of the 73d and 73e, respectively.
In this stored state, the capacitor element 70 is separated from the back plate 73a. Then, the molten insulating resin 74 is filled in the resin case 73 and solidified, so that the capacitor element 70 and the portions of the positive and negative external lead-out terminal plates 71 and 72 housed in the resin case 73 are removed. The output side film capacitor 6 is completed by completely sealing with resin. As the insulating resin 74, a thermosetting resin such as an epoxy resin or a polyurethane resin is used.

As shown in FIGS. 1 and 5, the output side film capacitor 6 is mounted in the case 1 by connecting the bottom plate 73b of the resin case 73 to a predetermined capacitor mounting portion 1B on the inner bottom surface of the case 1. A positioning hole 121 of a positioning plate 120 in which the positioning bent piece 105 of the negative side external lead-out terminal plate 72 is provided on the inner bottom surface of the case.
, The external terminal 72E is fixed to the positioning plate 120 by two setscrews 7, and one terminal 81A of the positive side external lead-out terminal plate 71 is connected to the IGBT 4 by the connection terminal 9. The other terminal 81B is connected to the external terminal 85.

In the input-side film capacitor 5 and the output-side film capacitor 6 having such structures,
Heat dissipation and heat shielding can be efficiently performed by the positive and negative external lead terminal plates, and the heat generation of the capacitor itself can be effectively reduced. Hereinafter, the reason will be described.

In the input-side film capacitor 5, the positive and negative external lead-out terminal plates 11, 12 have a large surface area, and the positive-side external lead-out terminal plate 1 has a large surface area.
1, the capacitor element 10 is included. When the capacitor element 10 generates heat by energizing the positive side external lead-out terminal plate 11, the heat is applied to the electrode portions 21 and 22.
Is transmitted through the radiator and radiates heat well. Further, the heat of the external lead terminal plates 11 and 12 on the plus side and the minus side is also transmitted to the case 1 via the insulating resin 14, the resin case 13 and the positioning plate 63 by heat conduction. Dissipates heat. Therefore, it is possible to provide the input-side film capacitor 5 having an excellent heat radiation effect.

In this case, the plus side external lead-out terminal plate 11
First bent piece 11B and the negative side external lead-out terminal plate 1
Since the second internal terminal portions 12A are in close contact with each other with the thin insulating film 59 interposed therebetween, the heat of the positive-side external lead-out terminal plate 11 can be transmitted well to the negative-side external lead-out terminal plate 12. Further, the terminal plate 12 for the negative external drawer
Is closer to the case 1 than the positive side external lead-out terminal plate 11, so that heat is released to the case 1 and the heat radiation effect is enhanced.

When the IGBT 4 generates heat or the ambient temperature of the heat sink 3 increases and the input side film capacitor 5 receives the heat, the capacitor is connected between the plus side and the minus side external lead-out terminal plates 11 and 12. Since the element 10 is included and covers the outer periphery and the electrode portions 21 and 22, the terminal plates 11 and 12 function as heat shields that block transmission of heat from the outside to the capacitor element 10. That is, even if the external heat is transmitted to the inside through the resin case 13, the positive and negative external lead-out terminal plates 11 and 12 receive the heat and radiate the heat to the outside without transmitting to the capacitor element 10. Therefore, a thermal effect on the capacitor element 10 can be reduced, and a film capacitor having a high heat shielding effect can be provided.

Further, the positive side external lead-out terminal plate 11 is
Since the two terminal portions 31A and 31B, the opening 33 and the slit 38 form a two-terminal type terminal circuit,
The impedance between the two terminals 31A and 31B is reduced, and the internal terminal 1
The eddy current generated at 1A can be reduced. Further, the second bent piece 11 of the positive side external lead-out terminal plate 11 is provided.
Since the open portion 41 that is opened by the slit 42 is provided in C, the eddy current generated in the second bent piece 11C can also be reduced. Therefore, it is possible to provide the input-side film capacitor 5 in which the positive side external lead-out terminal plate 11 itself generates less heat and generates less heat, and is suitable for use in a film capacitor requiring high frequency, large current and large voltage. is there.

Further, the terminal plate 12 for the negative side external drawer
Can be accurately positioned in the resin case 13. That is, since the corner portion of the resin case 13 is a portion having the highest strength, even if distortion occurs during molding, there is little deviation in dimensions, and the positioning provided on both sides of the rear end of the negative side external drawer terminal plate 12 is provided. By contacting the projection 50 for
An error in assembling the negative side external lead-out terminal plate 12 into the resin case 13 is reduced. Therefore, the resin case 1
When the heat sink 3 is fixed in the case 1, the positioning bent piece 57 of the negative-side external lead-out terminal plate 12 can be securely engaged with the positioning hole 64 of the positioning plate 63.

In the output-side film capacitor 6, the external lead terminal plates 71 and 72 on the plus side and the minus side each have a large surface area and are formed so as to include the capacitor element 70 in cooperation therewith. When the capacitor element 70 generates heat, the heat is radiated well. Also,
The heat of the external lead terminal plates 71 and 72 on the plus side and the minus side is also transmitted to the case 1 through the insulating resin 74, the resin case 73 and the positioning plate 120 by heat conduction, so that the heat is radiated by the heat sink 3. Therefore, it is possible to provide the output-side film capacitor 6 having an excellent heat radiation effect.

In this case, the positive side external lead-out terminal plate 71
The first and second bent pieces 71B and 71C and the first and second bent pieces 72B and 72C of the minus side external lead-out terminal plate 72.
Are closely contacted with each other via the thin insulating film 100, so that the heat of the plus side external drawing terminal plate 71 can be satisfactorily released to the minus side external drawing terminal plate 72. Further, since the negative side external lead-out terminal plate 72 is closer to the case 1 than the positive side external lead-out terminal plate 71, heat is transferred to the case 1.
Escape to enhance the heat dissipation effect.

When the IGBT 4 generates heat or the ambient temperature of the heat sink 3 becomes high and the output side film capacitor 6 receives the heat, the external lead terminal plates 71 and 72 on the plus side and the minus side are connected to the outside. This function as a heat shield plate that blocks the transfer of heat to the capacitor element 70, so that the thermal effect on the capacitor element 70 can be reduced. Therefore, it is possible to provide the film capacitor 6 having a heat shielding effect even against external heat.

Since the internal terminal 71A of the plus external lead-out internal terminal 71 is provided with an opening 83 opened by a slit 83a to form a terminal plate having a two-terminal structure, the impedance between the two terminal portions 81A and 81B is established. Can be reduced, and the heat generation of the terminal plate 71 itself can be reduced. Further, the internal terminal 71
A capacitor that generates less eddy current in A and generates less self-heating can be provided.

Further, the positive and negative external lead-out terminal plates 71, 72 can be accurately positioned in the resin case 73. That is, since the corner portion of the resin case 73 has the highest strength, even if distortion occurs during molding, there is little deviation in dimensions, and the rear ends of the positive and negative external lead-out terminal plates 71, 72. The positioning protrusions 87 and 98 provided on both sides abut on each other, thereby reducing the incorporation error of the plus and minus external lead-out terminal plates 71 and 72 into the resin case 73. Therefore, when the resin case 73 is fixed in the case 1 of the heat sink 3, the positioning bent piece 105 of the negative-side external lead-out terminal plate 72 can be securely engaged with the positioning hole 121 of the positioning plate 120. .

The present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the gist of the invention. For example, in the input side film capacitor 5, the capacitor element 1
The bent pieces covering the outer peripheral portions at both ends in the major axis direction may be formed by bending both end portions of the internal terminal portion 12A of the negative side external lead-out terminal plate 12. On the other hand, in the output-side film capacitor 6, the rear outer peripheral surface of the capacitor element 70 is attached to the rear end of the internal terminal 71A of the positive-side external lead-out terminal plate 71 or the internal terminal 72A of the negative-side external lead-out terminal plate 72. A folded piece for covering may be provided. Also, in the above-described embodiment, the case 1
Input and output film capacitors 5 and 6
Although an example in which the resin cases 13 and 73 are fixed horizontally has been described, the present invention is not limited to this. For example, in the case of a vertical plate-like heat sink, the heat sink is fixed to the vertical surface. You may.

[0056]

As described above, the film capacitor according to the present invention is excellent in heat radiation and heat shielding effects, and can reduce the heat generation of the capacitor itself. It can extend the life, and is particularly suitable as a capacitor used in a circuit requiring high frequency, large current and large voltage. Further, since the terminal plate has both the function as a heat radiator and the function as a heat shield, there is no need to provide a heat radiator and a heat shield made of separate members, and the number of components can be reduced.

According to the present invention, a two-terminal type terminal plate is formed by forming an opening and a slit in the positive-side external lead-out terminal plate. Reduce the generation of current,
Heat generation of the plus side external lead-out terminal plate can be further reduced.

Further, according to the present invention, the plus side external drawing terminal plate and the minus side external drawing terminal plate are provided with plate portions which are close to each other and opposed to each other and are in close contact with each other via an insulating member. And the heat dissipation effect can be further improved.

Further, according to the present invention, it is possible to accurately position the external lead-out terminal plate by the inner corner portion of the resin case, and to reduce an error in assembling the terminal plate into the resin case. .

Furthermore, according to the present invention, when the connection piece of the external lead-out terminal plate and the electrode portion of the capacitor element are joined by welding or soldering, since the heat capacity of the connection piece is small, the connection piece has a small heat capacity. Since heat conduction is fast and bonding can be performed quickly, and the temperature drops quickly after bonding, the thermal effect on the capacitor element can be reduced.

[Brief description of the drawings]

FIG. 1 shows an IGBT film capacitor according to the present invention.
FIG. 3 is a plan view of a main part of a part of one embodiment used for the snubber circuit shown in FIG.

FIG. 2 is a front view of an input-side film capacitor.

FIG. 3 is a sectional view of the film capacitor.

FIG. 4 is an exploded perspective view of the film capacitor.

FIG. 5 is a front view of an output-side film capacitor.

FIG. 6 is a sectional view of the film capacitor.

FIG. 7 is an exploded perspective view of the film capacitor.

[Explanation of symbols]

1. Case, 2. Cover, 3. Heat sink, 4. IG
BT, 5 ... input side film capacitor, 6 ... output side film capacitor, 10 ... capacitor element, 11 ... plus side external lead-out terminal plate, 11A ... internal terminal part, 11B ...
1st bent piece, 11C: 2nd bent piece, 11D: external terminal section, 12: negative side external lead-out terminal plate, 12A: internal terminal section, 12B: bent piece, 12C: external terminal section, 13
... resin case, 14 ... insulating resin, 21,22 ... electrode part,
33 ... opening, 34, 35 ... connection piece, 38 ... slit,
41 ... opening, 42 ... slit, 51, 52 ... connecting piece,
Reference numeral 59: insulating film, 70: capacitor element, 71: terminal plate for external lead-out on the positive side, 71A: internal terminal portion, 71
B: first bent piece, 71C: second bent piece, 71D: external terminal portion, 72: terminal plate for minus external pull-out, 72A
... Internal terminal part, 72B first bent piece, 72C second bent piece, 72E external terminal part, 73 resin case, 74
... insulating resin, 76, 77 ... electrode part, 83 ... opening part, 84
... Connection piece, 83a ... Slit, 95 ... Connection piece, 100 ...
Insulating film.

Continuing from the front page (72) Inventor Kaneko Miyashita Shinshu Shinmachi Ogata Shimomachi Plant, No. 155, Shinmachi Shinmachi, Nagano Pref. 2 Shinmachi Capacitor Co., Ltd. Shinmachi Plant (72) Inventor Hironobu Kusaba 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (72) Inventor Masaharu Yabo 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Stock In-company (72) Inventor Takayuki Doi 2nd Toyota Town, Toyota City, Aichi Prefecture TOYOTA MAX Co., Ltd. F-term (reference) 5E082 AA02 AB04 GG08

Claims (6)

[Claims] A capacitor element is housed in a resin case together with a positive side and a negative side external lead-out terminal plate integrally having an internal terminal portion and an external terminal portion, respectively, and sealed with a resin. Wherein the external terminal portion of the film capacitor protrudes outward from the case, wherein at least one of the positive-side external lead-out terminal plate and the negative-side external lead-out terminal plate is formed in a shape including the capacitor element. A film capacitor, wherein an internal terminal portion of each external lead-out terminal plate is joined to each electrode portion of the capacitor element. 2. A capacitor element is housed in a resin case together with a positive side and a negative side external lead-out terminal plate integrally having an internal terminal part and an external terminal part, respectively, and sealed with a resin. In the film capacitor in which the external terminal portion is projected outward of the case, the internal terminal portion of the positive-side external lead-out terminal plate is formed in a shape covering a surface of one electrode portion of the capacitor element, and has a central portion. A tongue-shaped connecting piece is integrally provided at an opening edge of the opening, and this connecting piece is joined to the one electrode portion, and the opening is connected to the positive electrode through a slit. A film capacitor, characterized in that it is open to an edge of a side external lead-out terminal plate, and the external terminal portions are integrally extended on both sides of the slit, respectively. 3. The film capacitor according to claim 1, wherein the positive external lead terminal plate and the negative external draw terminal plate are provided with plate portions facing each other and in contact with each other via an insulating member, A film capacitor, wherein the resin case is fixed to the heat sink such that the negative-side external lead-out terminal plate is closer to the heat sink than the positive-side external lead-out terminal plate. 4. The film capacitor according to claim 1, 2 or 3, wherein at least one of the positive side external lead-out terminal plate and the negative side negative lead-out terminal plate has a rear end edge at both ends. A film capacitor, wherein projections are integrally provided, and these positioning projections are in contact with inner corners of the resin case. 5. The film capacitor according to claim 2, wherein a connecting piece of the positive side external lead-out terminal plate is formed in a shape having a small heat capacity. 6. The film capacitor according to claim 1, wherein a plate portion that covers one side surface of the capacitor element is extended from the internal terminal portion of the positive-side external lead-out terminal plate. A film capacitor, characterized in that the plate portion has an opening that opens to the edge through a slit.