JP2014082026A - Manufacturing method of multilayer mold bus bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer mold bus bar capable of ensuring sufficient insulation between opposing conducting plates in resin molding of a conducting plate group.SOLUTION: When a conducting plate group formed of a plurality of conducting plates 8 opposing each other at a predetermined interval is disposed in a molding die to be resin-molded and buried in a resin molding part 6, each of the conducting plates 8 is held between holding pins 5 protruding from opposing dies of the molding die and reaching the conducting plate 8. The conducting plate is held by abutting, to the conducting plate 8, insulation pieces 7 which are mounted in distal ends of the holding pins 5. The insulation pieces are integrated with the resin molding part 6 by performing resin molding in the state where a gap between conducting plates and a space between the conducting plate and the molding die are maintained by holding.

Description

  The present invention relates to a method for manufacturing a multilayer molded bus bar.

The molded bus bar is obtained by molding a part of a current-carrying plate (bus bar) with a resin, and uses a non-molded portion for connection to electrical / electronic component terminals.
More specifically, the method of use is described below. In an electric vehicle or a hybrid vehicle, an inverter that converts electric power stored in a battery from direct current to alternating current is used. Molded bus bars are used for connection with terminals of electrical / electronic components.
In addition, when there are a wide variety of connection terminals, a plurality of energizing plates may be laminated and resin molded, and a multi-layer molded bus bar may be used in which the energizing plates are separated by an insulator. It will be selected as appropriate.

As shown in FIG. 1, a multilayer mold bus bar is manufactured by molding a bus bar 4 as an energizing plate from an upper mold 1a and a lower mold 2 into a mold mold 3 having an upper mold 1a, a middle mold 1b and a lower mold 2. It is held by a plurality of holding pins 5 protruding into the space, and the end of the bus bar 4 is fixed between the upper mold 1a and the middle mold 1b and between the middle mold 1b and the lower mold 2 and fixed. A resin molded portion 6 serving as an insulator is formed between the periphery excluding both ends and the bus bars 4.
In this manufacturing method, the bus bar 4 on the lowermost side in FIG. 1 is held by the holding pins 5 so that a space is formed between the bus bar 4 and the lower mold 2. However, since the upper bus bar 4 is blocked by the lower bus bar 4, a through hole 9 is provided in the lower bus bar 4, and the holding pin 5 is brought into contact with the upper bus bar 4 through the through hole 9. Thus, the space between the bus bars 4 is maintained.

The holding pin 5 is used to hold the bus bar 4 so that a space is formed between the bus bars 4 and between the bus bar 4 and the mold 3 in order to form the resin molding portion 6 around the bus bar 4. However, when the resin-molded molded bus bar is removed, it is held by the holding pin 5 (see FIG. 1) as shown in the perspective view in FIG. 2A and the perspective sectional view in FIG. 2B. In this portion, there is no resin molding part 6, and a hole 10 reaching the bus bar 4 from the surface of the molded bus bar is formed, and the bus bar 4 is exposed.
Since the exposed portion is not secured with electrical insulation, it is filled with resin by post-processing.

  Regarding the post-processing method, in Patent Document 1, the tip shape of the holding pin that holds the resin mold target (bus bar) is made the mold shape that forms the closing hole piece. It is disclosed that a pin is inserted to melt a closed hole piece to prevent exposure of a molding object.

JP 09-007722 A

However, since the pin disclosed in Patent Document 1 uses a pin twice, the number of steps is increased once, and positioning accuracy is required at the time of the second pin insertion, which increases the manufacturing time and the manufacturing cost.
In particular, in a multilayer molded bus bar, the number of hole-filled portions is larger than that in a single-layer bus bar, and the complicated work described in Patent Document 1 is not preferable.

  An object of the present invention is to provide a multilayer molded bus bar capable of ensuring sufficient insulation without requiring post-processing of a hole formed by a holding pin that comes into contact with the bus bar during resin molding of a resin molded portion.

  The present invention relates to the following method for producing a multilayer molded bus bar.

According to the manufacturing method of the present invention, a current plate group consisting of a plurality of current plates held opposite to each other with a predetermined interval is placed in a mold, resin-molded, and the gap between the opposite current plates is made of resin. In filling and embedding the current-carrying plate group in the resin molding portion with a part of the current-carrying plate group exposed, each of the current-carrying plates is sandwiched between holding pins that protrude from the opposing molds and reach the current-carrying plate. Held. Here, the holding is performed by bringing an insulating piece attached to the tip of the holding pin into contact with the energizing plate.
In the state where the gap between the current-carrying plates and the space between the current-carrying plates and the mold are maintained by the holding, the resin mold is performed so that the insulating piece is integrated with the resin-molded portion (claim). Item 1).
According to said invention, an electricity supply board is hold | maintained by contact | abutting the holding pin which attached the insulation piece at the front-end | tip from both surfaces of an electricity supply board. By this holding, a space for the resin mold is secured between the current-carrying plates of the current-carrying plate group and between the current-carrying plates and the mold surface. When the holding pin is removed after the resin mold, a hole leading to the outside remains in the trace. However, the insulating piece is embedded in the resin molding part and remains in the resin molding part as it is. Therefore, the insulating plate integrated with the resin molding portion is in contact with the energizing plate, and the hole is not blocked by the insulating piece and reaches the energizing plate.

The insulating piece preferably has a stepped portion having a configuration of a large-diameter portion and a small-diameter portion on an outer peripheral surface thereof (claim 2).
According to this configuration, the creepage distance at the interface between the insulating piece and the resin molded portion is increased. That is, the distance from the wall surface of the hole formed after removing the holding pin to the surface of the conductive plate through the interface increases.

  According to the present invention, the energizing plate is held by the holding pin and the resin mold is formed, but there is no need for post-processing, and the portion where the energizing plate is exposed at the trace after the holding pin is removed (originally the resin mold) It is possible to eliminate the portion that is exposed even though it should be done.

It is process drawing which shows the manufacturing method of the multilayer mold bus bar which is a prior art example. It is explanatory drawing of the multilayer mold bus bar which is a prior art example, (a) is a perspective view, (b) is a perspective sectional view. It is sectional drawing which shows embodiment of this invention. It is a perspective sectional view showing an embodiment of an insulating piece. It is explanatory drawing of the multilayer mold bus bar by embodiment of this invention, (a) is a perspective view, (b) is a perspective sectional view. It is explanatory drawing which shows the mode of an evaluation test.

<Electric plate>
The material of the current plate described in the present invention is not particularly limited as long as it conducts electricity, and more specifically, iron, copper, aluminum, gold, silver, etc. can be used, If copper is used, the electrical resistance is low and the amount of heat generated is small, and if aluminum is used, the weight can be reduced.
In addition, as the energizing plate, a plurality of types of alloys selected from the metals described above, and metals containing other metals, additives, and the like can be used.

The magnitude | size of an electricity supply board is not restrict | limited in particular, It can be set as the magnitude | size and shape according to the site | part used.
In addition, the electricity supply plate can be used by bending each part as required.

The energizing plate is divided into a portion used as a terminal and a portion covered with a resin molded portion described later. The resin molded portion is arranged so as to embed a group of current-carrying plates facing each other with a predetermined interval, and prevents the current-carrying plates from contacting each other.
The part used as a terminal is preferably provided at the end of the current-carrying plate, and compared to the case where a terminal is provided in the center, the shape of the mold used during resin molding can be simplified and the manufacturing cost can be reduced. it can.
The energizing plate is provided with a through hole for inserting a holding pin, which will be described later, at an appropriate location. The hole shape of the through hole may be a curved shape such as a circle, an ellipse, or a complex curved shape, or a polygonal shape such as a triangle or a quadrangle. The size of the through hole is preferably small in order to secure the surface area of the current-carrying plate as much as possible, that is, to secure the amount of surface current.

The energizing plate can be produced by punching a metal plate according to the usage pattern, and is produced by performing notching and bending as required.
In addition to punching, wire electrical discharge machining, laser machining, water jet machining, turret punching press machining, etc. can be used. If the number of manufactured products is small, wire electrical discharge machining is required rather than punching that requires a die. When using, the total cost is low and processing with high accuracy can be performed.
More specifically, a punching process is performed by punching an aluminum plate having a thickness of 1 to 3 mm, and a portion to be a terminal is made to stand by bending as necessary. In addition, this bending process can also be performed after the resin mold of the resin molding part mentioned later.

When connecting other electrical components to the part that becomes the terminal of the current plate, it is preferable to apply plating so that electrical connection can be easily and reliably, and if it is a copper bus bar, on the surface of the bus bar, Nickel plating and tin plating are performed. Moreover, such plating is preferable because it has an effect as rust prevention in addition to the ease of electrical connection.
Further, the shape of the portion to be a terminal is not limited, but it is preferable to make a hole for passing a bolt, and it is preferable to perform nickel plating or tin plating for rust prevention.
The part of the current plate embedded in the resin molded part does not necessarily require plating, but it is easy to plate the whole by dipping the current plate in the plating bath, so this part should also be plated with nickel or tin Is preferred.
When the current plate is made of aluminum, it is not always necessary to plate the surface.

<Insulation piece>
The insulating piece described in the present invention is used by being attached to the tip of the holding pin when the current-carrying plate group is sandwiched between the holding pins from both sides and the current-carrying plate group is positioned in the mold and the resin molding portion is resin-molded. Therefore, the insulating piece directly contacts the current plate.
The insulating piece is attached to each tip of the holding pin. And it is preferable to arrange | position a holding pin in several places of an electricity supply board so that an electricity supply plate can be supported stably.

As shown in FIG. 4A, the insulating piece 7 has a recessed portion 14 on one end face.
More specifically, the embodiment using the insulating piece 7 is shown in FIG. 3 in which the current-carrying plates 8 are stacked vertically and at a predetermined interval. The upper and lower current-carrying plates 8 are held by being held by holding pins 5 that protrude from the opposite molds, that is, the upper die 1 a and the lower die 2 and reach the current-carrying plate 8. The holding is performed by bringing the insulating piece 7 attached by inserting the tip of the holding pin 5 into the recessed portion 14 and abutting the current-carrying plate 8. As a matter of course, in order to sandwich the energizing plate 8 from both sides with the holding pins 5, the energizing plate 8 is appropriately provided with a through hole 9 for allowing the holding pin 5 to pass therethrough. Thereby, the gap between the current-carrying plates 8 is held, and when the current-carrying plate group is arranged in the mold, the space between the current-carrying plate 8 and the mold die (upper die 1a, lower die 2) is held.
FIG. 4B shows a mode in which a step portion 15 having a large diameter portion and a small diameter portion is provided on the outer peripheral surface of the insulating piece 7 of FIG. 4A described above. As the insulating pieces, those shown in FIGS. 4A and 4B can be used alone or in combination. In the aspect using the insulating piece in which the step portion 15 is formed, the creeping distance between the current-carrying plates facing each other is increased at the interface between the resin-molded resin molded portion (described later) and the insulating piece, and the insulation can be improved.

  In the above-described embodiment of the present invention, an example in which two energizing plates are used has been described. However, when three or more energizing plates are used, the present invention can be carried out according to the case of using two energizing plates.

  The material of the insulating piece is not particularly limited, but it is necessary to use an insulating piece. Specifically, those listed in the material of the resin molded portion described later can be used. In particular, it is preferable to use a polyphenylene sulfide resin because of its high insulation and relatively low cost. Moreover, you may mix | blend inorganic fillers, such as glass fiber, a glass bead, and a talc, with an insulating piece suitably for the purpose of improving heat resistance, dimensional stability, etc.

Moreover, in order to improve the adhesiveness with the resin molding part mentioned later, although it is preferable that an insulating piece is produced with the same kind resin as a resin molding part, it can also differ. When the resin material of the insulating piece is different from the resin material of the resin molded part, the surface of the insulating piece may be subjected to a surface roughening process, provision of fine protrusions, etc. in order to improve the adhesion to the resin molded part. preferable. In addition, by designing the thermal expansion coefficient of the insulating piece to be close to the thermal expansion coefficient of the resin molded part, it is possible to prevent interface breakdown between the resin molded part and the insulating piece during long-term use.
In addition, when using PBT (polybutylene terephthalate) resin for the resin material which forms a resin molding part and an insulation piece, the adhesiveness of a resin molding part and an insulation piece may worsen by a heat shock. In such a case, as a measure for improving the adhesion, the material of the primary molded product (insulating piece) is a low melting point PBT resin or an elastomer-modified resin.
The insulating piece can be produced by various conventionally known methods. However, if the insulating piece is produced in large quantities with high accuracy, it is preferably produced by injection molding.

<Resin molding part>
The resin molded portion described in the present invention is for embedding the above-described current plate group in a state in which a part (portion serving as a terminal) is exposed. Insulate.
The resin material used for the resin molded portion is not particularly limited as long as insulation can be ensured. Specifically, thermoplastic resins, thermosetting resins, rubbers, and the like can be used.
Moreover, you may mix | blend suitably inorganic fillers, such as glass fiber, a glass bead, and a talc, in the resin material which comprises a resin molding part, in order to improve heat resistance, dimensional stability, etc.

  Thermoplastic resin materials include ionomer resin, aminopolyacrylamide resin, isobutylene maleic anhydride copolymer resin, ABS (acrylonitrile-butadiene-styrene copolymer), ACS (acrylonitrile-chlorinated polyethylene-styrene copolymer), AES ( Acrylonitrile-ethylene-styrene copolymer), AS (acrylonitrile-styrene copolymer), ASA (acrylonitrile-styrene-acrylic copolymer), MBS (methyl methacrylate-butadiene-styrene copolymer), ethylene vinyl chloride copolymer resin , Ethylene vinyl acetate copolymer resin, ethylene vinyl acetate vinyl chloride graft polymer resin, ethylene vinyl alcohol copolymer resin, chlorinated polyvinyl chloride resin, chlorinated polyethylene resin Chlorinated polypropylene resin, carboxyvinyl polymer resin, ketone resin, brominated polystyrene resin, amorphous copolyester resin, norbornene resin, fluorinated ethylene polypropylene copolymer resin, PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether), polychlorotri Fluoroethylene resin, ethylenetetrafluoroethylene copolymer resin, low melting point ethylenetetrafluoroethylene copolymer resin, polyvinylidene fluoride resin, polyvinyl fluoride resin, polyacetal resin, polyamide resin, polyamideimide resin, polyarylate resin, thermoplastic polyimide resin, poly Etherimide resin, polyetheretherketone resin, polyethylene resin, polyolefin emulsion resin, polyethylene oxide Fatty, polyethylene terephthalate resin, polyethylene naphthalate resin, polyvinylidene chloride resin, polyvinylidene chloride latex resin, polyvinyl chloride resin, polycarbonate resin, polyvinyl acetate resin, polystyrene resin, polysulfone resin, polyparavinylphenol resin, polyparamethyl Styrene resin, polyallylamine resin, polyvinyl alcohol resin, polyvinyl ether resin, polyvinyl butyral resin, polyvinyl formal resin, polyphenylene ether resin, polyphenylene sulfide resin, polybutadiene resin, polybutylene terephthalate resin, polypropylene resin, polymethylpentene resin, polymethyl methacrylate Resin, liquid crystal polymer resin, etc. can be used, especially polyphenylene sulfide resin It is preferable that the insulating property is high and the cost is relatively low.

  Thermosetting resin materials include epoxy resin, oligoester acrylate resin, xylene resin, guanamine resin, diallyl phthalate resin, DFK resin (resorcinol resin), thermosetting resin prepolymer, vinyl ester resin, phenol resin, unsaturated Polyester resin, furan resin, polyimide resin, polyurethane resin, maleic acid resin, melamine resin, urea resin and the like can be used.

  As rubber materials, SBR (styrene / butadiene rubber), BR (butadiene rubber), IR (isoprene rubber), EPM (ethylene / propylene rubber), EPDM (ethylene / propylene / diene rubber), NBR (nitrile rubber), Chloroprene rubber, IIR (butyl rubber), urethane rubber, silicone rubber, polysulfide rubber, nitrile hydroxide rubber, fluorine rubber, ethylene tetrafluoride / propylene rubber, ethylene tetrafluoride / propylene / vinylidene fluoride rubber, acrylic rubber, chloro Sulfonated polyethylene rubber, epichlorohydrin rubber, ethylene / acrylic rubber, liquid rubber, olefin-based thermoplastic elastomer, urethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, vinyl chloride-based thermoplastic Elastomers, may be used a fluorine-based thermoplastic elastomer.

<Method for producing multilayer molded bus bar>
Although the manufacturing method of a multilayer mold bus bar is not restrict | limited, It demonstrates below using drawing.
The multilayer mold bus bar uses the current-carrying plate and the insulating piece described above. By using a holding pin with an insulating piece attached to the tip, the energizing plate group has a space between the energizing plate and the mold surface, with the energizing plates facing each other having a predetermined gap in the mold. The space for holding and arranging the resin molding part is secured.
Again, an example will be described with reference to FIG. 3. Each of the energizing plates 8 is held between the holding pins 5 that protrude from the upper mold 1 a and the lower mold 2 and reach the energizing plate 8. The holding is performed by bringing an insulating piece 7 attached to the tip of the holding pin 5 into contact with the energizing plate 8. With the support by the holding pin 5, a gap between the current-carrying plates 8 is ensured, and when the current-carrying plate group is arranged in the mold, a space between the current-carrying plate 8 and the mold die (upper die 1a, lower die 2) is secured. doing. As described above, the group of current-carrying plates 8 arranged in the mold 3 is resin-molded by the resin-molded portion 6 together with the insulating pieces by injection-molding resin. Thereafter, the resin is solidified and removed from the mold, thereby forming a multilayer molded bus bar (see FIG. 5).
In the multilayer molded bus bar, a hole 10 is formed from the surface toward the inside at the trace after the holding pin 5 is removed. However, as shown in FIG. 5 (b), the hole 10 does not reach the energizing plate and is blocked by the insulating piece 7, so that the energizing plate is not exposed.

<Preparation of insulation piece>
Two types of insulating pieces were prepared, one shown in FIG. 4A and one shown in FIG.
The insulating piece shown in FIG. 4A has a cylindrical shape with a diameter of 4.0 mm and a height of 3.0 mm, and a concavity with a diameter of 1.5 mm and a depth of 2.0 mm concentric with the cylindrical end surface. A portion 14 is provided.
The insulating piece of FIG. 4B is the insulating piece of FIG. 4A, and the stepped portion 15 is formed by providing a small diameter portion having a diameter of 3.0 mm and a height of 0.5 mm at both ends.
Both of these insulating pieces were produced by injection molding using PPS reinforced resin in which glass fiber: 30% by mass and mineral powder: 20% by mass were added as inorganic fillers to PPS resin: 50% by mass. Is.

<Preparation of current plate>
As the current-carrying plate, a copper plate having a length of 15 mm, a width of 100 mm, and a height (thickness) of 1.5 mm was prepared, and the surface of this copper plate was subjected to nickel plating.
The energization plate was provided with a plurality of through holes (diameter: 5.0 mm) for passing through the holding pins described above at predetermined positions. That is, the through holes of the energizing plate disposed on the upper side were provided at two locations of 20 mm and 60 mm from one end face along the longitudinal center line of the energizing plate. Moreover, the through-hole of the electricity supply board arrange | positioned below was provided in two places of 40 mm and 80 mm from one end surface along the longitudinal direction center line of an electricity supply board (refer FIG.5 (b)).

Example 1
A multilayer molded bus bar was produced using the insulating piece and the current plate 8 described above.
Specifically, the procedure described with reference to FIG. 3 is followed. First, an insulating piece is attached to the tip of the holding pin. Next, after disposing the current-carrying plate in the mold, the mold is closed. And the PPS resin of the same material composition as an insulating piece was inject | poured in the mold, and the resin molding part 6 was shape | molded. The molding conditions were: resin (cylinder) temperature: 320 ° C., mold temperature: 150 ° C., molding cycle: 60 seconds.

(Example 2)
As an equivalent to the insulating piece used in Example 1, instead of this, a multilayer molded bus bar was produced in the same manner as in Example 1 using the insulating piece shown in FIG.

<Dielectric strength test>
With respect to the multilayer molded bus bar produced in Examples 1 and 2 described above, a dielectric strength test was performed. As shown in FIG. 6, the insulation withstand voltage test is performed by connecting the cable 16 to the exposed portion of the current plate 8 using an insulation withstand voltage tester (manufactured by Kikusui Electronics Co., Ltd., trade name: TOS5050A). Application was continued for 2 seconds, and the leakage current was measured.
The multilayer molded bus bar according to Example 1 was confirmed to have a leakage current of 100 μA or less.
In addition, the multilayer molded bus bar according to Example 2 was similarly tested, and it was confirmed that the leakage current was 30 μA or less.

  In the production of the multilayer molded bus bar according to the present invention, a hole that reaches the current plate from the surface of the resin molded portion and exposes the current plate is not formed without the need for post-processing to close the hole formed in the trace of the holding pin. . The gap between the opposing energizing plates is securely held even during the resin mold, and deformation of the energizing plates due to the pressure of the resin flow in the resin mold is prevented. It was confirmed that the insulating property was also secured.

  When the outer peripheral portion of the insulating piece is shaped to have a large-diameter portion and a small-diameter portion, the creeping distance at the interface between the insulating piece and the resin-molded portion can be increased to further improve the insulating performance (Example 2).

1a: Upper mold, 1b: Medium mold, 2: Lower mold, 3: Mold mold, 4: Bus bar,
5: Holding pin, 6: Resin molding part, 7: Insulating piece, 8: Current supply plate, 9: Through hole,
10: hole, 14: recessed part, 15: step part, 16: cable

Claims (2)

An energizing plate group composed of a plurality of energizing plates held opposite to each other at a predetermined interval is placed in a mold, resin-molded, and a gap between opposing energizing plates is filled with resin, and the energizing plate group is When embedding in the resin molded part with a part of it exposed,
Each energizing plate is held by holding pins that protrude from the opposite molds of the mold and reach the energizing plate, and the holding is performed by contacting an insulating piece attached to the tip of the holding pin with the energizing plate. Performed by
A multilayer mold characterized in that, by the holding, a gap between the current-carrying plates and a space between the current-carrying plates and the mold are maintained, and the resin mold is performed so that the insulating piece is integrated with the resin-molded portion. Manufacturing method for busbars.   2. The method of manufacturing a multilayer molded bus bar according to claim 1, wherein the outer peripheral surface of the insulating piece has a stepped portion having a large diameter portion and a small diameter portion.

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