JP4342253B2 - Resin mold electrode - Google Patents

Description

  The present invention relates to an improvement in a resin mold electrode in which an electrode metal is insert-molded integrally with a synthetic resin.

  A resin mold electrode that is insert-molded integrally with the synthetic resin so that at least a part of both surfaces of the plate-like electrode metal is covered with the synthetic resin is, for example, a power conversion such as a DC-DC converter. In various electric devices to which predetermined electric parts such as devices are assembled, this is adopted when electrodes for power supply, signals, etc. are integrally provided in a synthetic resin case. Such a resin mold electrode is insert-molded so that the plate-like electrode metal 100 is embedded in the synthetic resin 102 as shown in FIG. 5 (a), for example. Due to the shrinkage of 102 or the difference in thermal expansion from the electrode metal 100, it is deformed as shown in FIG. For this reason, for example, when it is required to form the lower surface flatly as indicated by the alternate long and short dash line in (b), the shape at the time of molding in (a) is indicated by the alternate long and short dash line in anticipation of deformation after molding However, since it is necessary to correct the molding surface of the mold by trial and error, there is a problem that it is troublesome and takes time and costs are increased. In particular, when a part of one surface of the electrode metal is exposed and a metal terminal such as aluminum or gold is connected by vibration welding or the like, the synthetic resin is unevenly distributed and the balance of shrinkage force is lost. The deformation of the electrode becomes significant.

  On the other hand, in Patent Document 1, for example, by omitting the lower synthetic resin, the bottom surface of the case (resin mold electrode) is molded to be convex downward by deformation after insert molding, and the corners are formed. By fixing to the heat sink with a bolt or the like, the lower surface is brought into close contact with the heat sink so that heat can be radiated satisfactorily. Patent Document 2 proposes to control deformation caused by shrinkage of the synthetic resin after molding by providing an insulator and changing the embedding depth of the electrode metal by the synthetic resin.

JP 2002-373970 A JP-A-3-232257

  However, in the case of Patent Document 1, since the electrode metal is exposed, it is necessary to provide an insulating heat radiation sheet between the heat sink and in the case of Patent Document 2, an insulator is embedded together with the electrode metal. Since it is necessary, all of them are not always satisfactory because the number of parts increases and the manufacturing cost increases.

  The present invention has been made against the background of the above circumstances, and its object is to obtain a desired electrode shape by controlling deformation after molding without requiring a separate member. is there.

To achieve the above object, the first invention is embedded in the synthetic resin as a pair of plate-shaped electrode metal in parallel to overlap substantially one another in the resin mold electrodes are integrally insert molding, (a) Each of the pair of electrode metals has a longitudinal shape, and one electrode metal has a convex curved shape in which a cross section perpendicular to the longitudinal direction is convex outward, while the other electrode metal is In consideration of deformation due to shrinkage or the like of the synthetic resin after the insert molding , the synthetic resin volume outside each of the pair of electrode metals has a predetermined ratio and a predetermined rigidity is obtained. The convex curve shape of the one electrode metal is defined in FIG.

The second aspect, in the first shot Ming resin mold electrode, the electrode metal and substantially parallel one end face of the heat radiating surface which is fixed so as to be in close contact with the cooler, the cooler side thereof radiating surface or flat The ratio of the synthetic resin volume on the outside of each of the pair of electrode metals and the convex curve shape of the one electrode metal are determined so as to form a gentle convex curve shape .
According to a third aspect of the present invention, in the resin molded electrode according to the second aspect, the heat dissipation surface is an end surface on the one electrode metal side of the pair of electrode metals.

In this way, when the pair of electrode metals are embedded in the synthetic resin so as to substantially overlap each other in parallel, the intermediate synthetic resin layer positioned between the pair of electrode metals has a dimension (moment arm) from the center of the plate thickness. Since the length) is short, the deformation moment that contributes to the deformation of the resin mold electrode due to the contraction is small, and the contraction of the synthetic resin outside each of the pair of electrode metals away from the center of the plate thickness greatly affects the deformation. Therefore, in consideration of deformation due to shrinkage of the synthetic resin after insert molding , the convexity of one electrode metal is such that the outer synthetic resin volume of each of the pair of electrode metals has a predetermined ratio and a predetermined rigidity is obtained. If the curved shape is set, the deformation of the resin mold electrode is controlled based on the contraction force of the synthetic resin and the directionality of the rigidity of the electrode metal, and the desired shape can be obtained without using an insulator as in Patent Document 2. It can be obtained and can be configured easily and inexpensively. In addition, since synthetic resin exists on the outside of each of the pair of electrode metals, an insulating heat radiation sheet is interposed even when one end face is closely attached to a cooler such as a heat sink as in the second invention. Without being touched, it can be fixed by directly contacting the heat sink.

Furthermore, any pair of electrode metal with forms a longitudinal shape, one electrode metal, by perpendicular cross-section to its longitudinal direction is a convex curved shape, the pair of electrode metal Since each outer synthetic resin volume has a predetermined ratio, by appropriately setting the direction, depth, size, etc. of the curve, the volume ratio of the electrode metal can be easily set. Stiffness can be controlled.

The second invention is a case where one end face substantially parallel to the electrode metal is a heat radiating surface and fixed so as to be in close contact with the cooler, and the heat radiating surface is flat or has a gentle convex curve on the cooler side. Since the ratio of the synthetic resin volume on the outside of each of the pair of electrode metals and the convex curve shape of one of the electrode metals are determined , the peripheral part is integrated with a flat cooler with screws or the like By fixing to, the heat radiation surface is brought into close contact with the cooler so as to be in surface contact, and an excellent heat radiation action is obtained.

Deformation of the resin molded electrode, contractile force or resin volume or resin shrinkage of the synthetic resin, the arm length of the moment from the thickness center, based on the such linear expansion coefficient, the amount of deformation, both outer (pair of electrodes difference and complexes of resin contraction force of outside) of each metal (Sadamari based like the stiffness of the laminate) of the electrode metal and synthetic resin, deformation directions of both outer side difference of the resin contraction force, the complex It is determined based on the position of the center of gravity and the difference in rigidity in the plate thickness direction of the electrode metal. Therefore, based on the thickness direction of the stiffness of the resin volume and electrode metal on both outer sides of the pair of electrode metal, it is possible to control the deformation of the resin molded electrode is a complex, in the present invention, the synthetic resin volume By setting the convex curve shape of one electrode metal so as to have a predetermined ratio, the deformation of the resin mold electrode is controlled based on the volume ratio of the synthetic resin and the rigidity of the electrode metal.

  The present invention is preferably applied to an electrode mounting structure for a case of an electric device such as a power conversion device such as a DC-DC converter, but can also be applied to other resin mold electrodes. The electrode may be anything as long as it supplies electricity, such as one that supplies a predetermined electric power or one that transmits an electric signal.

One electrode metal is cross-section is a convex curved shape may be deformed over the entire length of the long side direction, for example, if a portion is used as a vibration welding surface, a part of the length even only a convex curved shape not good.

In the second invention, one end surface is a heat radiating surface and is integrally fixed to a cooler such as a heat sink. However, when the first invention is carried out, it is not necessarily fixed to the cooler. Further, the shape of the resin mold electrode is not necessarily flat, and the volume ratio of the synthetic resin can be set so as to positively bend into a predetermined shape.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic perspective view showing a case 12 of an electric apparatus such as a DC-DC converter integrally including a resin mold electrode 10 according to an embodiment of the present invention. The resin mold electrode 10 is shown in FIG. A pair of electrode metals 14 and 16 are provided, and connection electrodes 18 and 20 are provided on the electrode metals 14 and 16, respectively. The electrode metals 14 and 16 are made of a metal plate having a long conductive shape such as copper or copper alloy, and are arranged so as to substantially overlap each other in parallel and constitute a case 12. It is insert-molded integrally with a synthetic resin (for example, PPS containing glass fiber) 26 and embedded in the synthetic resin 26. 2A is a perspective view showing a pair of electrode metals 14 and 16 independently, and FIG. 2B is a cross-sectional view perpendicular to the longitudinal direction of the resin mold electrode 10 having the electrode metals 14 and 16. c) is a longitudinal sectional view of the resin mold electrode 10.

  The lower electrode metal 14 is completely embedded and covered with a synthetic resin 26 except for the connection terminals 18, but the upper electrode metal 16 has a part of its upper surface exposed and a vibration welding surface 28. The connection terminals such as aluminum and gold are integrally connected by vibration welding. Further, the lower end surface 22 of the case 12 is fixed so as to be in close contact with a heat sink 24 as a cooler so as to dissipate heat. The lower end surface 22 corresponds to a heat radiating surface.

  The resin mold electrode 10 of the present embodiment has a shrinkage of the synthetic resin 26 after insert molding, a difference in thermal expansion (difference in linear expansion coefficient) between the synthetic resin 26 and the electrode metals 14 and 16, and Considering the drag due to rigidity, the volume A of the synthetic resin 26 above the electrode metal 16 and the electrode metal 14 so that the lower end surface 22 is substantially flat or slightly convexly curved regardless of the contraction or the like. Further, the volume ratio A / B with the volume B of the synthetic resin 26 on the lower side, that is, the lower end surface 22 side, is set to be in the range of 0.5 to 0.8. That is, the upper electrode metal 16 is flat, but the lower electrode metal 14 is provided with a groove-shaped recess 30 having a predetermined depth extending in the longitudinal direction in advance by press working, and the entire length in the longitudinal direction. The cross section is a convex curved shape that protrudes downward, and the volume ratio A / B becomes a predetermined value without correcting the molding die for molding the synthetic resin 26. The depth dimension of the recess 30 is set. The synthetic resin 26 in the middle portion between the electrode metals 14 and 16 has a short moment arm length (vertical dimension from the center of the plate thickness) that contributes to deformation, so that the resin mold electrode 10 is hardly deformed. No effect.

  In addition, since the cross section of the electrode metal 14 is formed in a convex curve shape in this way, a predetermined rigidity is obtained in the thickness direction, and a predetermined resistance against deformation due to shrinkage of the synthetic resin 26 after molding is obtained. Drag is obtained.

  The lower electrode metal 14 is also provided with a flange 32 bent upward at a substantially right angle at the end opposite to the connection terminal 18 and embedded in the side wall 34 of the case 12 as shown in FIG. It is like that. As a result, the contraction force of the side wall 34 after the insert molding acts on the flange 32 and a bending moment is generated in the electrode metal 14. Furthermore, the deformation of the resin mold electrode 10 can be controlled.

  Thus, in the resin mold electrode 10 of the present embodiment, the volume ratio A / B of the synthetic resin 26 above and below the electrode metals 14 and 16 is predetermined in consideration of deformation due to shrinkage of the synthetic resin 26 after insert molding. Since the shapes of the electrode metals 14 and 16 are determined so that a predetermined rigidity can be obtained, the resin is based on the contraction force of the synthetic resin 26 and the directionality of the rigidity of the electrode metals 14 and 16. The deformation of the mold electrode 10 is controlled, and a desired shape can be obtained without using an insulator as in Patent Document 2, and the configuration can be simple and inexpensive.

  Further, the electrode metal 14 has a cross section perpendicular to the longitudinal direction thereof having a convex curved shape, so that the synthetic resin volume B below the electrode metal 14 and the volume ratio A / B are adjusted. Therefore, the volume ratio A / B can be easily set to a predetermined value and the rigidity of the electrode metal 14 can be controlled by appropriately setting the direction, depth, size, etc. of the curve. .

  Further, the lower end surface 22 substantially parallel to the electrode metals 14 and 16 is a heat radiating surface and is fixed so as to be in close contact with the heat sink 24, but the volume ratio A / B of the synthetic resin 26 is 0.5 to 0.8. Therefore, the lower end surface 22 has a substantially flat or gentle convex curved shape, and the lower end surface 22 is fixed to the flat contact surface of the heat sink 24 by integrally fixing the peripheral edge with a screw or the like. It is made to adhere well so as to come into surface contact, and an excellent heat dissipation action is obtained.

  FIG. 4 shows an upper synthetic resin 42 when insert molding is performed such that the upper and lower surfaces of the metal plate 40 made of the same material as the electrode metals 14 and 16 are completely covered with the synthetic resins 42 and 44 as shown in FIG. The ratio A / B between the volume A and the volume B of the lower synthetic resin 44 is continuously changed, and the deformation of the composite 46 due to the shrinkage of the synthetic resins 42 and 44 after molding is examined ( It is shown in b). The displacement amount (+) in (b) is the displacement amount when the central portion of the composite body 46 changes upward, that is, a convex curve shape projecting toward the synthetic resin 42, and the displacement amount (-) is the composite amount. This is the amount of displacement when the central part of the body 46 changes downward, that is, in a convex curve shape that protrudes toward the synthetic resin 44. When the volume ratio A / B is around 0.6, the deformation is substantially zero, and if it is smaller than that, It is convex upward, and when it is large, it protrudes downward. Therefore, in the present embodiment in which the volume ratio A / B is 0.5 to 0.8, the deformation is substantially 0 and the lower end surface 22 becomes a substantially flat surface or a convex curved shape that slightly protrudes downward. . It should be noted that the deformation becomes substantially zero when the volume ratio A / B is around 0.6 because the side walls 34 as shown in FIG. Since the contraction force of the side wall 34 causes the central portion of the composite 46 to protrude downward (synthetic resin 44 side), the volume of the synthetic resin 44 opposite to the side wall 34 is increased. By increasing the contraction force by increasing, it is considered that the contraction force balances and the deformation becomes substantially zero.

  Further, in this embodiment, the synthetic resin 26 is also present on the lower end surface 22 side of the electrode metal 14, and the lower end surface 22 is constituted by the surface of the synthetic resin 26. The heat sink 24 can be directly contacted and fixed without interposing a heat radiating sheet.

  Further, in this embodiment, a flange 32 is provided at the end of the lower electrode metal 14 and is embedded in the side wall 34 of the case 12, and a bending moment is applied to the electrode metal 14 based on the shrinkage of the side wall 34 after insert molding. Therefore, it is possible to control the magnitude of the bending moment by appropriately setting the thickness of the side wall 34 and the like, and the resin combined with the difference in contraction force due to the volume ratio A / B and the rigidity of the electrode metal 14. The deformation of the mold electrode 10 can be controlled more finely.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention implements in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.

It is a schematic perspective view which shows the case of the electric apparatus which is integrally provided with the resin mold electrode which is one Example of this invention. FIG. 2 is a diagram illustrating the resin mold electrode of FIG. 1, (a) is a perspective view independently showing a pair of electrode metals, (b) is a cross-sectional view of the resin mold electrode, and (c) is a longitudinal view of the resin mold electrode. It is sectional drawing. It is sectional drawing which shows the part by which the flange provided in the edge part of one electrode metal was embed | buried under the side wall of a case. It is a figure explaining the result of having investigated the amount of displacement of a composite by changing volume ratio A / B of the upper and lower synthetic resins, when insert-molding so that the upper and lower surfaces of a metal plate material may be covered with a synthetic resin. It is a figure explaining the deformation | transformation by the shrinkage | contraction etc. of the conventional resin mold electrode, and the correction which anticipated the deformation | transformation.

Explanation of symbols

  10: Resin mold electrode 14, 16: Electrode metal 22: Lower end surface (heat radiation surface) 24: Heat sink (cooler) 26: Synthetic resin

Claims (3)

In a resin mold electrode in which a pair of plate-like electrode metals are embedded in a synthetic resin so as to substantially overlap each other in parallel and are integrally formed by insert molding,
Each of the pair of electrode metals has a longitudinal shape, and one electrode metal has a convex curved shape in which a cross section perpendicular to the longitudinal direction is convex outward, while the other electrode metal is Flat,
Taking into account the deformation due to contraction of the synthetic resin after the insert molding, the pair of each of the electrode metal in the outer synthetic resin volume the one electrode metal as and predetermined stiffness becomes a predetermined ratio to obtain A resin-molded electrode characterized by having a convex curved shape . One end face substantially parallel to the electrode metal is a heat dissipating surface fixed so as to be in close contact with the cooler, and the heat dissipating surface is flat or has a gentle convex curve on the cooler side. The resin mold electrode according to claim 1, wherein a ratio of a volume of the synthetic resin on each outer side of the electrode metal and a convex curve shape of the one electrode metal are defined . The heat dissipation surface is an end surface on the one electrode metal side of the pair of electrode metals.
The resin mold electrode according to claim 2.

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