JP2014229673A - Coil coating body and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil coating body capable of solving the problem of degradation of insulation performance due to peeling of an intermediate insulation layer, insulating between coil blocks, and a resin coating layer at a junction, and to provide a manufacturing method therefor.SOLUTION: In a coil coating body 16 for coating a conductor coil 14, where an upper coil 14-1 and a lower coil 14-2 are superposed vertically with an intermediate insulation layer 20 interposed therebetween, with a resin coating layer 38 consisting of an injection molding of an electrically insulating and thermoplastic resin, having an outer peripheral coating 38A, inner peripheral coating 38B, a first end face coating 38C and a second end face coating 38D, from the outside so as to generally surround the conductor coil, the intermediate insulation layer 20 is formed of thermoplastic resin, the outer peripheral coating 38A and inner peripheral coating 38B have a lamination structure of inner surface layers 38A-1, 38B-1 extending to pass the end of the intermediate insulation layer 20, and outer surface layers 38A-2, 38B-2 on the outside thereof, and the intermediate insulation layer 20 is injection molded integrally with the inner surface layers 38A-1, 38B-1.

Description

  The present invention relates to a coil covering formed by covering a conductor coil formed by winding a wire in a state in which an insulating film is interposed between the wire and a wire in a state of being wrapped with an electrically insulating resin, and a method for manufacturing the same.

  In hybrid vehicles, fuel cell vehicles, electric vehicles, etc., a booster circuit is provided between the battery and an inverter that supplies AC power to the motor (electric motor), and a reactor (choke coil) that is an inductance component is provided in the booster circuit. ) Is used.

For example, in a hybrid vehicle, the battery voltage is about 300 V at the maximum, while it is necessary to apply a high voltage of about 600 V to the motor to obtain a large output. For this purpose, a reactor is used as a component for a booster circuit.
This reactor is also widely used for boosting circuits of photovoltaic power generation and others.

  Conventionally, a coil formed by winding a wire with an insulating film (usually made of polyamide-imide resin) as the reactor (a coil formed by winding a wire with an insulating film sandwiched therebetween. Coil as a representative coil) is covered with an electrically insulating resin to form a coil covering, and in this state, the soft magnetic powder and the resin are integrally contained. The thing of the form which shape | molded the mixed material and used as the core is known.

Here, the insulating coating of the wire has a role as functional insulation, and is applied for the purpose of preventing a short circuit between the wires, and is usually a coating having a thickness of about 10 to 50 μm. With this coating alone, under the conditions of high voltage use, it is impossible to prevent electric shock between the wire and the outside (device, human body, etc.) even if insulation between the wires can be secured.
Therefore, the role of the electrically insulating resin coating layer that envelops the entire coil is to ensure insulation for the purpose of protection from electric shock. The thicker the resin coating layer, the higher the insulation performance, but it is disadvantageous in the following points.
That is, since the resin coating layer is not electromagnetically involved, if the coating is thick, the reactor itself becomes large. Moreover, since the resin used has low thermal conductivity, the heat dissipation for escaping the heat generated by the coil is deteriorated.
Therefore, it is desirable to make this resin coating layer as thin as possible within the range that satisfies the insulation performance.
The resin coating layer has a role of protecting the insulating coating of the wire as another role, and there is a resin coating layer whether the core is potted (cast) or injection molded. Provides the following advantages.

In the former potting molding, with a coil formed by winding a wire with an insulating coating set in a container, a thermosetting resin liquid in which soft magnetic powder is mixed in a dispersed state is injected into it, and then this is applied. The core is formed by heating the resin liquid to a predetermined temperature and curing the resin liquid over a predetermined time, but in the case of the reactor of the above form, the resin liquid mixed with the soft magnetic powder is injected by the resin coating layer that wraps the coil. Sometimes, it is possible to prevent the soft magnetic powder made of iron powder or the like from directly hitting or rubbing against the insulating coating and damaging it.
Further, it is possible to prevent the insulating coating from being damaged due to stress applied to the insulating coating due to curing shrinkage when the thermosetting resin is cured.
Furthermore, when a mixed material of soft magnetic powder and thermosetting resin liquid is injected into the container, the coil can be prevented from being deformed by the injection pressure or flow pressure.

In the latter core molding by injection molding, a coil is set in a cavity of a molding die, and a mixed material of soft magnetic powder and thermoplastic resin is injected there to mold a core. With the resin coating layer, it is possible to prevent the soft magnetic powder from directly hitting or rubbing against the insulating coating and damaging the insulating coating, or the coil can be prevented from being deformed by the injection pressure or flow pressure.
Moreover, it can prevent that the thermal stress resulting from shrinkage | contraction of a shaping | molding core is added to an insulating film, and this is damaged.

  Although the case where the coil formed by winding the wire with the insulation coating is described above, the wire is wound in a state where the insulation film is interposed between the bare wire and the wire without using the wire with the insulation coating. Even in the case of using the formed coil, the reactor of the above configuration can provide the same advantages as the case of using a coil with an insulating coating, such as prevention of displacement and deformation of the coil during core molding.

By the way, as a manufacturing method of the coil covering, a method in which a resin coating layer for covering a coil is injection-molded using a thermoplastic resin is preferable because it can be molded in a short time and has high productivity. In this case, how to keep the coil positioned in the cavity of the mold and how to prevent the coil from being deformed by the injection pressure or the flow pressure is great. It becomes a problem.
If the coil is greatly deformed at the time of molding, the characteristics of the reactor are deteriorated in the same manner as described above.
A technique aimed at solving this problem is disclosed in Patent Document 1 below.

FIG. 34 shows a specific example thereof.
In the drawing, reference numeral 200 denotes a coil, and 202 denotes a resin coating layer made of a thermoplastic resin that covers the coil 200 so as to be entirely wrapped from the outside.
Here, the coil 200 has a height in the direction of the coil axis when the upper coil block (hereinafter simply referred to as the upper coil) 200-1 and the lower coil block (hereinafter simply referred to as the lower coil) 200-2 are connected to each other. In the direction, an intermediate insulating sheet 204 that is a separate body from the resin coating layer 202 is stacked in two stages with the intermediate insulating sheet 204 interposed therebetween.

  The resin coating layer 202 is formed of an injection-molded body, and includes an outer peripheral coating portion 206 that covers the entire outer peripheral surface of the coil 200, an inner peripheral coating portion 208 that covers the entire inner peripheral surface, and one first in the coil axis direction. An upper end surface covering portion (first end surface covering portion) 210 that covers the entire end surface (here, the upper end surface) and a lower end surface covering portion (second end) that entirely covers the other second end surface (here, the lower end surface). End face covering portion) 212.

In the one disclosed in Patent Document 1, the resin coating layer 202 made of an electrically insulating thermoplastic resin is injection-molded separately in a primary molding step and a secondary molding step.
First, in the primary molding step, as shown in FIG. 34A, the coil 200 is set on the primary molding die 214 together with the intermediate insulating sheet 204 (here, the upper coil 200-1 is on the lower side and the lower coil 200 is on the lower side). -2 is set on the upper side), and the primary molding die 214 is brought into contact with the inner peripheral surface of the coil 200 to position the coil 200 in the radial direction. A thermoplastic resin material is injected from the injection port into the cavity 218 of the primary mold 214 to be formed, and the outer peripheral covering portion 206 and the lower end surface covering portion 212 are integrally formed as a primary molded body.

  In the secondary molding step, as shown in FIG. 34B, the coil 200 and the primary molded body after the primary molding are turned upside down with respect to FIG. The coil 200 and the primary molded body, that is, the outer periphery covering portion 206 and the lower end surface covering portion 212 are positioned in the radial direction by bringing the secondary molding die 216 into contact with the outer periphery surface of the outer periphery covering portion 206, and the coil The same resin material as that in the primary molding step is injected into the cavity 220 of the secondary molding die 216 formed on the inner peripheral side and the upper side of the 200, and the inner peripheral covering portion 208 and the upper end surface covering portion 210 are secondary. Molded integrally as a molded body.

In this way, a coil cover 205 shown in FIG. 34C is obtained.
FIG. 35 shows a reactor 224 in which a core 222 is formed by injection molding a mixed material of a soft magnetic component and a thermoplastic resin in a state in which the obtained coil covering 205 is included.
In the coil coating member 205 shown in FIG. 34, and the outer covering portion 206 and the upper surface covering portion 210 are joined together at joint surfaces _{P 1,} and in the inner circumference covering portion 208 and the lower surface covering portion 212 and the joining surface _{P 2} They are joined together.
Furthermore the outer peripheral edge surface and the outer covering portion 206 and the inner peripheral end face and the inner peripheral cover portion 208 of the intermediate insulating sheet 204 becomes each other and the bonding state at each junction plane P _3.

By the way, the coil sheath has a mechanical load such as vibration, such as thermal load such as rapid start from below freezing point, continuous operation at high load, intermittent operation at high load and low load, under long-term actual use environment. , Exposed to environmental loads such as intrusion of contaminants such as dust and water vapor, alone or in combination.
Therefore, in the coil cover 205 shown in FIG. 34C, at the beginning of manufacture, the outer peripheral end surface of the intermediate insulating sheet 204 that is separate from the resin cover layer 202, the outer peripheral cover portion 102, and the inner peripheral end surface. Even if the inner peripheral covering portion 208 is in a joined state at those joints, if the resin coating layer 202 and the intermediate insulating sheet 204 are repeatedly expanded and contracted due to repeated application of a thermal load or a mechanical load, There is a possibility that the outer peripheral end face of the insulating sheet 204 and the outer peripheral covering portion 202 and the inner peripheral end face thereof and the inner peripheral covering portion 208 are peeled off at the respective joint portions, and a minute gap is generated there.

Thus, when the intermediate insulating sheet 204 and the resin coating layer 202 are separated at the joint and a minute gap is generated, the insulation between the upper coil 200-1 and the lower coil 200-2 is impaired, A high voltage applied between the upper coil 200-1 and the lower coil 200-2 causes a spark discharge (flashover), which may cause a dielectric breakdown.
In addition, there is a risk that corona discharge may occur due to continuous application of high-frequency voltage even in smaller gaps that do not lead to dielectric breakdown, or gaps that do not penetrate, leading to deterioration in insulation performance and leading to dielectric breakdown. is there.
Such a short-circuit problem in which spark discharge or corona discharge occurs between coil blocks is common in the case where a coil is coated with a resin coating layer regardless of whether or not the resin coating layer is joined at a seam. Occur.

  Here, the role of the intermediate insulating sheet corresponds to the same functional insulation as that of the insulating coating of the wire when considered closely, and aims at insulation between the coil blocks. However, the difference between the two is that the potential difference is about one to two digits larger in the intermediate insulating layer (intermediate insulating sheet). Therefore, the damage caused by dielectric breakdown is greater in the intermediate insulating layer. Therefore, high insulation performance according to the resin coating layer that wraps the entire coil for the purpose of protection from electric shock must be satisfied even when a long-term thermal load, mechanical load, and environmental load are applied.

As prior art to the present invention, the following Patent Document 2 discloses an invention relating to a “reactor”, in which an inner coil block and an outer coil block of an edgewise coil are connected to an intermediate insulating layer (insulating member (FIG. 5)). A point overlapped in the radial direction via 6)) is disclosed.
In the device disclosed in Patent Document 2, the entire coil is not covered and covered with a resin coating layer, and the above problem is not disclosed, and the solution is not disclosed. Not in.

International Publication No. 2011/118508 JP 2010-267768 A

  In the background of the above circumstances, the present invention solves the problem of deterioration in insulation performance caused by separation of the intermediate insulation layer and the resin coating layer that insulates between the coil blocks at the joint, and provides long-term thermal An object of the present invention is to provide a coil covering that can ensure reliability even when a load, a mechanical load, and an environmental load are applied, and a method for manufacturing the same.

  Thus, claim 1 relates to a coil covering, which is formed by winding the wire in a state in which an insulating film is interposed between the wire and a plurality of coil blocks connected to each other in the coil axis direction. An outer peripheral covering portion that covers the outer peripheral surface of the coil, and an inner peripheral covering portion that covers the inner peripheral surface of the conductor coil that is coaxially overlapped with the intermediate insulating layer interposed therebetween in the vertical direction and / or radial direction , An injection molded body of an electrically insulating thermoplastic resin having a first end face covering portion covering one first end face in the axial direction and a second end face covering portion covering the other second end face in the axial direction. A coil covering formed by covering a resin covering layer so as to be entirely encased from the outside, wherein the intermediate insulating layer is formed of a thermoplastic resin, and the outer peripheral covering portion, the inner peripheral covering portion, The intermediate insulation of the end face covering portion and the second end face covering portion. At least one of the crossover covering portions crossing the inner insulating layer is formed as a laminated structure of an inner surface layer extending through the end of the intermediate insulating layer and an outer surface layer outside the inner surface layer, and the intermediate layer is integrated with the inner surface layer. The insulating layer is formed by injection molding.

  According to a second aspect of the present invention, in the first aspect, the coil is a flatwise coil, and an upper coil block and a lower coil block are vertically stacked in the height direction, and the upper coil block and the lower coil block are The intermediate insulating layer is interposed in a state extending in the radial direction, and at least one of the outer peripheral covering portion and the inner peripheral covering portion serving as the cross covering portion is formed between the inner surface layer and the outer surface layer. It is a laminated structure, and the intermediate insulating layer is formed integrally with the inner surface layer by injection molding.

  According to a third aspect of the present invention, in the second aspect, the coil terminals protrude radially outward from the upper coil block and the lower coil block, respectively, and the outer peripheral covering portion is a laminated structure of the inner surface layer and the outer surface layer. Thus, the intermediate insulating layer is integrally formed with the inner surface layer by injection molding.

  According to a fourth aspect of the present invention, in the second aspect, the coil terminal protrudes radially inward from each of the upper coil block and the lower coil block, and the inner peripheral covering portion is a laminate of the inner surface layer and the outer surface layer. The intermediate insulating layer is formed by injection molding integrally with the inner surface layer.

  A fifth aspect of the present invention relates to a method of manufacturing a coil covering, and in manufacturing the coil covering according to any one of the first to fourth aspects, the steps of injection molding the resin coating layer include a primary molding step and a secondary step. In the primary molding process, a slidable plate-like spacer is sandwiched between the coil block and the coil block, and the inner surface layer molding is performed between the coil block and the coil block. Forming a gap for forming the intermediate insulating layer in communication with the cavity for injecting the resin material while drawing and moving the spacer, and drawing the resin material by drawing and moving the cavity and the gap and the spacer. The primary molded body of the resin coating layer including the inner surface layer and the intermediate insulating layer are integrally injected and molded into the space formed, and the coil is then inserted into the intermediate in the subsequent secondary molding step. A secondary molded body of the resin coating layer is injection-molded in a state of being wrapped together with the primary molded body including an edge layer and the inner surface layer, and the outer peripheral covering portion, the inner peripheral covering portion, the first end face covering portion, and the second end face The entire covering portion is formed.

  The manufacturing method of claim 6 is characterized in that, in claim 5, the spacer is automatically retracted and moved by the flow pressure of the injected resin.

Effects and effects of the invention

  As described above, the coil covering body of the present invention includes an outer periphery covering portion, an inner periphery covering portion, a first end surface covering portion, and a first end covering portion of a resin covering layer formed of an injection molded body of a thermoplastic resin that entirely encloses a coil from the outside. Among the two end face covering portions, at least one of the cross covering portions intersecting with the intermediate insulating layer is formed as a laminated structure of an inner surface layer extending through the end of the intermediate insulating layer and an outer surface layer outside thereof, and the inner surface thereof. An intermediate insulating layer is formed by injection molding integrally with the layer.

  In the coil cover of the present invention, the end face of the intermediate insulating layer is joined from the crossover cover such as the outer periphery cover and the inner cover as in the conventional coil cover by repeatedly applying a thermal load or a mechanical load. There is no fear of delamination, and therefore, the insulation performance of the intermediate insulating layer is impaired by the debonding, and spark discharge and corona discharge occur between the coil blocks stacked with the intermediate insulating layer in between, causing a rare short circuit. The problem can be solved.

Here, at least one of the cross-covering portions means a cross-covering portion on the side where bonding and peeling with the intermediate insulating layer are particularly problematic.
For example, the coil is an edgewise coil, and an inner coil block and an outer coil block are stacked in a radial direction orthogonal to the winding direction of the wire, and an intermediate insulating layer between them is positioned in the coil axial direction (high In the case where the first end face covering portion extends in the radial direction, the first end face covering portion and the second end face covering portion become the cross covering portion.
In this case, in the present invention, each of the first end face covering portion and the second end face covering portion has a laminated structure of an inner surface layer and an outer surface layer, and an intermediate insulating layer is integrally injection-molded with respect to each inner surface layer. Can be kept.

The coil is a flatwise coil, and the upper coil block and the lower coil block are vertically stacked in two steps in the height direction (vertical direction) perpendicular to the winding direction of the wire. When the intermediate insulating layer between the lower coil block extends in the radial direction, the outer peripheral covering portion and the inner peripheral covering portion extending in the height direction (coil axis direction) become the cross covering portion.
Also in this case, each of the outer peripheral covering portion and the inner peripheral covering portion can have a laminated structure of an inner surface layer and an outer surface layer, and an intermediate insulating layer can be integrally injection-molded with respect to these inner surface layers ( Claim 2).

  However, in the present invention, each of the above two cross-coating portions has a laminated structure of an inner surface layer and an outer surface layer, and the intermediate insulating layer does not have to be integrally formed with each inner surface layer. Only one of them can have a laminated structure of an inner surface layer and an outer surface layer, and an intermediate insulating layer can be integrally injection molded to the inner surface layer.

For example, in the latter case (flatwise coil), when the coil terminals protrude radially outward from the upper coil block and the lower coil block, only the outer peripheral covering portion has the above laminated structure, and the inner surface The intermediate insulating layer can be integrally formed only on the layer (Claim 3).
The potential difference between the upper coil block and the lower coil block is the largest at the outermost part of the coil and the smallest at the innermost part. This is because the upper coil block and the lower coil block are directly connected on the innermost periphery.
Therefore, the potential difference generated in one turn of the innermost circumference of the coil is a value obtained by dividing the total potential difference generated on the outermost circumference side by the total number of turns of the coil, and the inner circumference side may not require higher insulation than the outer circumference side. Many.
Therefore, in such a case, the intermediate insulating layer may be integrally injection-molded only on the outer peripheral covering portion, more specifically on the inner surface layer.
That is, in this case, the outer peripheral covering portion becomes the cross covering portion on the side where the bonding and peeling with the intermediate insulating layer is particularly problematic. The intermediate insulating layer is injection-molded integrally.

On the other hand, when the coil terminal protrudes radially inward from the upper coil block and the lower coil block, at least the inner peripheral covering portion has a laminated structure of an inner surface layer and an outer surface layer, On the other hand, an intermediate insulating layer is integrally injection-molded (Claim 4).
That is, in this case, the inner peripheral covering portion becomes the cross covering portion on the side where the bonding and peeling with the intermediate insulating layer is particularly problematic.

  If the upper coil block, intermediate coil block, and lower coil block are stacked in three steps in the height direction, intermediate insulation is provided between the upper coil block and the intermediate coil block, and between the intermediate coil block and the lower coil block. The above intermediate insulating layer is formed by injection molding integrally with the inner surface layer, with both of the outer periphery covering portion and the inner periphery covering portion being a laminated structure of the inner surface layer and the outer surface layer. Is good.

Next, claim 5 relates to a method of manufacturing the coil covering body. In this manufacturing method, the resin coating layer is divided into a primary molding step and a secondary molding step, and injection molding is performed.
In the primary molding step, a slidable plate-like spacer is sandwiched between the coil blocks, a gap communicating with the cavity for molding the inner surface layer is formed between the coil blocks, and the spacer is The resin material is injected while being drawn in, filled in the cavity and the gap, and the space generated by the drawing movement of the spacer, and the intermediate molded body of the resin coating layer including the inner surface layer and the intermediate insulation The layers are injection molded together.
In the subsequent secondary molding step, the secondary molded body of the resin coating layer is injection-molded so as to wrap the coil together with the primary molded body including the intermediate insulating layer and the inner surface layer. The first end face covering portion and the second end face covering portion are formed as a whole.

By such a method, the resin coating layer surrounding the coil can be formed by injection molding, and the intermediate insulating layer for insulating the coil blocks can be formed by injection molding.
In this case, the intermediate insulating layer can be molded integrally with the cross covering portion so that the boundary between the intermediate insulating layer and the cross covering portion such as the outer peripheral covering portion and the inner peripheral covering portion does not become a joint. .
That is, the coil covering according to any one of claims 1 to 4 can be manufactured satisfactorily by this manufacturing method.

In the manufacturing method according to claim 5, in the primary molding step, the primary molding die is brought into contact with at least a part of the inner peripheral surface or / and the outer peripheral surface of the coil, and the coil is positioned in the radial direction. The primary molded body can be molded together with the intermediate insulating layer.
By doing in this way, when forming the primary molded object in a resin coating layer with an intermediate | middle insulating layer, it can prevent that a coil will shift or deform | transform.

In the manufacturing method of claim 5, the secondary forming step of the resin coating layer may be performed once, or may be performed in a plurality of times.
That is, in the secondary molding process, a part of the secondary molded body may be molded in the pre-molding process, the remaining part may be molded in the subsequent post-molding process, and may be joined to the part molded in the pre-molding process. .

In the above manufacturing method, the spacer can be automatically drawn and moved by the flow pressure of the injected resin (claim 6).
In this way, since the resin material pushes the spacer at the protruding position (extrusion position) in the pulling direction by the flow pressure, the spacer can be automatically pulled and moved at an appropriate timing. In addition, the configuration of the molding apparatus can be simplified.
However, it is also possible to force the spacer to be pulled in by hydraulic or other actuators, or to push it out to a predetermined advance position.

It is the figure which showed the coil coating | coated body of one Embodiment of this invention with the reactor. It is the perspective view which decomposed | disassembled and showed the reactor of FIG. It is principal part sectional drawing of the reactor of FIG. It is an external appearance perspective view of the coil of FIG. It is the external appearance perspective view which showed the primary coil covering body in the same embodiment with the coil covering body. It is a figure for demonstrating the process of the manufacturing method of the coil coating body of the embodiment. It is the figure which decomposed | disassembled the primary shaping | molding die for resin coating layer shaping | molding into the upper mold | type and the lower mold | type, and showed it with the coil. It is a figure for demonstrating the structure of the lower mold | type of FIG. It is a cross-sectional view in a state where a coil is set in the primary mold of FIG. It is a longitudinal cross-sectional view in the state which set the coil to the primary shaping | molding die of FIG. It is an enlarged view of the principal part for demonstrating the process of primary shaping | molding. It is an enlarged view of the principal part different from FIG. It is sectional drawing of the primary coil coating | covering body in the same embodiment. It is the figure which decomposed | disassembled the secondary shaping | molding die for resin coating layer shaping | molding into the upper mold | type and the lower mold | die, and the primary coil coating | covering body. It is a figure for demonstrating the structure of the secondary shaping | molding die of FIG. FIG. 15 is a transverse cross-sectional view in a state where a primary coil covering is set on the secondary mold of FIG. 14. It is a longitudinal cross-sectional view in the state which set the primary coil covering body to the secondary shaping | molding die of FIG. It is an enlarged view of the principal part for demonstrating the process of secondary shaping | molding. It is an enlarged view of the principal part different from FIG. It is sectional drawing of the coil coating body after the secondary shaping | molding of the same embodiment. It is the figure which showed the welding jig | tool used with the manufacturing method of the embodiment with the coil coating | covering body. It is a figure for demonstrating the content of the welding process of the embodiment. It is a figure for demonstrating the process of the primary shaping | molding of the core in a reactor. It is a figure for demonstrating the process of the secondary shaping | molding of the core following FIG. It is sectional drawing which shows the coil coating body of other embodiment of this invention with a primary coil coating body. It is an external appearance perspective view of the primary coil covering body of FIG. 25, and a coil covering body. It is a principal part enlarged view for demonstrating the process of the primary shaping | molding of the resin coating layer in the embodiment. It is a principal part enlarged view for demonstrating the process of the secondary shaping | molding following FIG. It is sectional drawing which shows the coil coating body of further another embodiment of this invention with a primary coil coating body. FIG. 30 is an external perspective view of the primary coil covering body of FIG. 29. It is sectional drawing which shows the coil coating body of further another embodiment of this invention with a primary coil coating body. It is the figure which showed other coil coating bodies of this invention with the principal part of the reactor. It is the figure which showed the reactor case used by the test of the Example. It is the figure which showed an example of the manufacturing method of the conventional coil coating body. It is the figure which showed the reactor using the conventional coil coating | covering body.

Next, an embodiment when the present invention is applied to a coil covering used in a reactor (choke coil) as an inductance component will be described in detail below based on the drawings.
In FIGS. 1 and 2, reference numeral 10 denotes a reactor, and a coil 14 formed by winding a wire with an insulating coating around a core 12 made of a soft magnetic resin molded body is integrated in a buried state as a coil covering 16 described later. It has become. That is, the core 12 is fabricated so as to be a reactor having a structure without a gap.

In this embodiment, the coil 14 is a flatwise coil formed by winding a rectangular wire with an insulating film in the wire thickness direction, and as shown in FIG. 4, an upper coil block (hereinafter simply referred to as an upper coil) 14-1. And a lower coil block (hereinafter simply referred to as a lower coil) 14-2 in a height direction (coil axis direction) that is orthogonal to the winding direction of the wires so that the magnetic fields do not cancel each other. As shown in FIG. 4B, the end portions on the inner peripheral side are joined at the connection portion 17 and are configured as one continuous coil.
However, as shown in FIG. 4C, the upper coil 14-1 and the lower coil 14-2 may be continuously configured with a single wire.
In FIG. 4C, 18 represents a transition portion between the upper coil 14-1 and the lower coil 14-2.

FIG. 1B and FIG. 3 are cross-sectional views showing the internal structure of the reactor 10 (however, in these drawings, the left side and the right side show cross sections of different shapes).
Here, since a potential difference is generated between the upper coil 14-1 and the lower coil 14-2, an annular intermediate insulating layer 20 is formed between them as shown in FIG. 1B and FIG. (Here, the intermediate insulating layer 20 has a thickness of about 0.5 mm). The intermediate insulating layer 20 will be described in detail later.
In the drawing, reference numeral 22 denotes a coil terminal in the coil 14, which protrudes radially outward from the upper coil 14-1 and the lower coil 14-2.

As shown in FIG. 4, the coil 14 has an annular shape in plan view.
As shown in FIG. 1A, the coil 14 is entirely embedded in an embedded state in the core 12 except for a part on the tip side of the coil terminal 22.
In this embodiment, the coil 14 can be made of various materials such as copper, aluminum, copper alloy, aluminum alloy (however, in this embodiment, the coil 14 is made of copper).

In this example, the core 12 is made of a molded body obtained by injection molding a mixed material of soft magnetic powder and thermoplastic resin.
Here, soft magnetic iron powder, sendust powder, ferrite powder, or the like can be used as the soft magnetic powder. Examples of the thermoplastic resin include PPS (polyphenylene sulfide), PEEK (polyether ether ketone), PA12 (polyamide 12), PA6 (polyamide 6), PA6T (polyamide 6T), POM (polyoxymethylene), PE (polyethylene). ), PES (polyether sulfone), PVC (polyvinyl chloride), EVA (ethylene vinyl acetate copolymer), and the like can be suitably used.
The ratio of the soft magnetic powder to the core 12 can be various ratios, but is preferably 50 to 70% by volume.

As shown in the exploded view of FIG. 2, the core 12 is formed by joining a primary molded body 12-1 and a secondary molded body 12-2 by injection molding. In FIG. 1, K indicates a joint surface between the primary molded body 12-1 and the secondary molded body 12-2.
As shown in FIGS. 1 and 2, the primary molded body 12-1 is positioned on a cylindrical outer peripheral side molded portion 24 that comes into contact with the outer peripheral surface of the coil cover body 16, which will be described later, and on the lower side of the coil cover body 16 in the figure. It has a container shape having a bottom portion 26 and a shape having an opening 28 at the upper end in the drawing in the coil axis direction.
Note that a cutout portion 30 is provided in the outer peripheral side molding portion 24 of the primary molded body 12-1.
The notch 30 is for fitting a later-described thick portion 32 (see FIG. 2) of the coil cover 16.

  On the other hand, as shown in FIG. 2, the secondary molded body 12-2 is in contact with the inner peripheral surface of the coil covering body 16 and fills a void inside the coil 14 to form the bottom of the primary molded body 12-1. 26 is located on the upper side in the drawing of the coil covering body 16 and the opening 28 in the primary molded body 12-1 is closed, and the recess of the primary molded body 12-1 is closed. And an upper circular lid portion 36 for concealing the coil covering body 16 accommodated therein in an integral manner.

The coil cover 16 is formed by wrapping and covering the entire coil 14 (except for a part on the tip end side of the coil terminal 22) with a resin cover layer 38. The coil 14 serves as the core cover 12 as the coil cover 16. Embedded inside.
The resin coating layer 38 of the coil coating body 16 is also composed of a primary molded body 38-1 and a secondary molded body 38-2 shown in FIGS. 3 and 5, which are joined to each other by injection molding. ing.
Here, the primary molded body 38-1 and the secondary molded body 38-2 of the resin coating layer 38 are made of an injection molded body of an electrically insulating thermoplastic resin that does not contain soft magnetic powder. As the thermoplastic resin, PPS, PEEK, PA12, PA6, PA6T, POM, PE, PES, PVC, EVA and other various materials can be used.
The primary molded body 38-1 and the secondary molded body 38-2 may be made of the same material or different materials.

  In addition, it has high heat resistance, hardly hydrolyzes after long-term use, high fluidity during molding, linear expansion coefficient is closer to the metal used in the coil, high mechanical strength and fatigue strength, low cost It is more desirable that a certain property can be achieved singly or simultaneously. From such a viewpoint, a PPS resin, particularly a PPS resin to which glass fiber or carbon fiber is added is desirable.

  The resin coating layer 38 in the coil coating 16 also includes an outer peripheral coating portion 38A that covers the entire outer peripheral surface of the coil 14, an inner peripheral coating portion 38B that covers the entire inner peripheral surface, and one of the coils 14 in the axial direction. It has an upper end surface covering portion (first end surface covering portion) 38C that covers the entire upper end surface that is the end surface, and a lower end surface covering portion (second end surface covering portion) 38D that covers the entire lower surface that is the other end surface. doing.

The outer periphery covering portion 38A has a two-layer structure of an inner surface layer 38A-1 located on the inner surface side and an outer surface layer 38A-2 located on the outer surface side.
Similarly, the inner peripheral covering portion 38B also has a two-layer laminated structure of an inner surface layer 38B-1 and an outer surface layer 38B-2.
Here, the inner surface layer 38A-1 of the outer periphery covering portion 38A and the inner surface layer 38B-1 of the inner periphery covering portion 38B are respectively formed over the entire periphery.
The outer peripheral covering portion 38A and the inner peripheral covering portion 38B serve as a cross covering portion for the intermediate insulating layer 20, and the inner surface layers 38A-1 and 38B-1 are continuous with the intermediate insulating layer 20. The inner surface 38A-1 in the outer peripheral covering portion 38A and the inner surface layer 38B-1 in the inner peripheral covering portion 38B are both ends of the intermediate insulating layer 20 (left in the figure). , Right end) and extends in the axial direction of the coil 14.
In this example, the inner surface layer 38B-1 in the inner periphery covering portion 38B can be omitted in some cases as will be clarified later.

Here, the length in the vertical direction in the drawing of the inner surface layer 38A-1 in the outer periphery covering portion 38A and the inner surface layer 38B-1 in the inner periphery covering portion 38B is obtained between the upper coil 14-1 and the lower coil 14-2. The length can be set appropriately according to the creepage distance. Here, the creepage distance refers to the shortest distance along the surface of the insulator between the upper coil 14-1 and the lower coil 14-2. The creepage distance is determined based on the insulation strength required for the equipment, the rated voltage value and the assumed overvoltage level, the degree of contamination, the tracking resistance of the insulator, and the like.
Here, these inner surface layers 38A-1 and 38B-1 are formed with the following lengths.

Specifically, although the outer surface layer 38A-2 in the outer peripheral covering portion 38A is formed over the entire height of the coil 14, the inner surface layer 38A-1 has an overall height in the axial direction of the coil 14 as shown in FIG. The length in the coil axis direction is shorter than the length in the same direction of the entire coil 14. However, an inner surface layer 38C-1 in the upper end surface covering portion 38C, which will be described later, and a portion connected to the inner surface layer 38D-1 in the lower end surface covering portion 38D are formed over the entire height of the coil 14 in order to support them. Yes.
Further, in the inner peripheral covering portion 38B, the outer surface layer 38B-2 is formed over the entire height of the coil 14, but the inner surface layer 38B-1 is not formed over the entire height of the coil 14 in the axial direction. The length in the coil axis direction is shorter than the length in the same direction of the entire coil 14.

  As described above, in the inner surface layer 38A-1 in the outer periphery covering portion 38A and the inner surface layer 38B-1 in the inner periphery covering portion 38B, the entire circumference or a part thereof is made shorter than the total axial length of the coil 14 as a whole. The reason is that this portion suppresses displacement and deformation of the coil 14 at the time of injection molding, and the coil 14 is not completely covered by the position displacement of the coil 14 at the time of injection molding, and a part thereof is partially exposed. This is to prevent this.

The upper end surface covering portion 38C also has a two-layer laminated structure of an inner surface layer 38C-1 and an outer surface layer 38C-2.
However, in the upper end surface covering portion 38C, the inner surface layer 38C-1 is partially provided at four locations separated by 90 ° in the circumferential direction as clearly shown in FIG. This part has a single-layer structure of the outer surface layer 38C-2.
That is, in other portions, the outer surface layer 38C-2 is in direct contact with the upper end surface of the coil 14.
Here, the inner surface layer 38C-1 is formed continuously with the inner surface layer 38A-1 in the outer periphery covering portion 38A.

However, this is only an example. A part or all of the inner surface layer 38C-1 in the upper end surface covering portion 38C may be formed continuously with the inner surface layer 38B-1 in the inner peripheral covering portion 38B. Since the state of the resin flow changes depending on the connection portion, these may be determined so that the coil 14 is not partially exposed.
Further, the arrangement interval and the number of the inner surface layer 38C-1 in the upper end surface covering portion 38C are merely an example. As the number of arrangements increases, the positioning stability during injection molding of the secondary molded body 38-2 increases, but conversely, the resin flow during the injection molding of the primary molded body 38-1 becomes complicated, and the coil There is an increased risk of 14 being partially exposed. Therefore, it is necessary to determine the number of arrangements by comprehensively considering the state of resin flow in primary molding and the state of positional deviation in secondary molding.

  In the upper end surface covering portion 38C, the supporting protrusion 40 that protrudes upward in the drawing from the upper surface of the inner surface layer 38C-1 and has a circular shape in plan view and forms a part of the upper end surface covering portion 38C is formed in the inner surface layer 38C-1. The outer surface layer 38C-2 surrounds the peripheral surface around the supporting projection 40.

As shown in FIG. 5, the inner surface layer 38 </ b> C- 1 has a shape extending along the end surface on the inner side (lower side in the drawing) on the upper end surface side of the coil 14 with respect to the support protrusion 40. The visual shape is larger than the support protrusion 40.
That is, the supporting protrusion 40 protrudes upward in the drawing from the position drawn inward in the plan view from the outer peripheral edge of the inner surface layer 38C-1.
The outer surface layer 38C-2 is laminated around the supporting protrusion 40 on the outer side of the inner surface layer 38C-1, and is superposed on the inner surface layer 38C-1 in the vertical direction in the figure.
In the upper end surface covering portion 38C, the upper surface of the supporting protrusion 40 is flush with the upper surface of the outer surface layer 38C-2 when the coil covering body 16 is completed.

On the other hand, the lower end surface covering portion 38D also has an inner surface layer 38D-1 and an outer surface layer 38D-2, which form a laminated structure, and the support protrusions 40 face downward in the drawing from the inner surface layer 38D-1. It is protruding.
The shape or structure of the lower end surface covering portion 38D is the same as that of the upper end surface covering portion 38C except that the vertical direction is reversed, and further detailed description is omitted.

In this embodiment, between the upper coil 14-1 and the lower coil 14-2, the same electrical insulating properties as the outer peripheral covering portion 38A, the inner peripheral covering portion 38B, the upper end surface covering portion 38C, and the lower end surface covering portion 38D are provided. An intermediate insulating layer 20 made of a thermoplastic resin is interposed.
An inner surface layer 38A-1 in the outer periphery covering portion 38A, an inner surface layer 38B-1 in the inner periphery covering portion 38B, a supporting protrusion 40 forming a part of the upper end surface covering 38C, and an inner surface layer 38A-1 and a lower end surface covering portion inside thereof. The supporting projection 40 forming a part of 38D and the inner surface layer 38D-1 on the inside thereof constitute the primary molded body 38-1 which is continuously connected integrally, and this primary molded body 38 is formed. -1 is formed integrally with the intermediate insulating layer 20 described above.

  On the other hand, the outer surface layer 38A-2 in the outer peripheral covering portion 38A2, the outer surface layer 38B-2 in the inner peripheral covering portion 38B, the outer surface layer 38C-2 in the upper end surface covering portion 38C and the outer surface layer 38D-2 in the lower end surface covering portion 38D are integrated. The secondary molded body 38-2 is connected continuously.

In this embodiment, the thickness of the intermediate insulating layer 20 is, for example, 0.5 mm, the thickness of the inner surface layer 38A-1 in the outer peripheral covering portion 38A is 1 mm, the thickness of the outer surface layer 38A-2 is 1 mm (2 mm in total), In the covering portion 38B, the thickness of the inner surface layer 38B-1 is 1 mm, and the thickness of the outer surface layer 38B-2 is 1 mm (2 mm in total).
Further, the thickness of the inner surface layer 38C-1 in the upper end surface covering portion 38C is 0.5 mm, and the thickness of the outer surface layer 38C-2 in the portion superposed on the inner surface layer 38C-1 is 0.5 mm (1 mm in total).
Therefore, the protrusion height of the support protrusion 40 is 1 mm when the coil covering body 16 is completed.
Note that the thickness of the portion where the outer surface layer 38C-2 is a single layer is 1 mm.
The thickness of each portion in the lower end surface covering portion 38D is the same as the thickness of each portion in the upper end surface covering portion 38C.
However, these are only examples. The thickness of the resin coating layer 38 depends on the physical properties of the insulator (dielectric strength, mechanical strength, fatigue strength), the stress applied to the coating layer, the flow characteristics during molding, the configuration of each coating portion (single layer, laminated), etc. It is determined.

Next, the manufacturing method of the reactor 10 of this embodiment is demonstrated below.
First, FIG. 6 shows a schematic process of the manufacturing method of the coil covering 16.
As shown in FIG. 6, here, first, primary forming is performed to form the primary molded body 38-1 shown in FIG. 3 together with the intermediate insulating layer 20.
Then, secondary molding is performed, and the secondary molded body 38-2 is molded in a laminated state with respect to the primary molded body 38-1, so that the resin coating layer 38 in the coil coating body 16 is molded.

7 to 12 specifically show the method for forming the primary molded body 38-1 together with the method for forming the intermediate insulating layer 20. The specific contents of the primary molding will be described below based on these drawings.
7 to 9 show the configuration of a primary mold used for primary molding.
In FIG. 7, reference numeral 42 denotes a primary mold, and the primary mold 42 has an upper mold 42-1 and a lower mold 42-2.
The upper mold 42-1 and the lower mold 42-2 are provided with recesses 44-1 and 44-2 for accommodating the coil 14, respectively.
The recess 44-2 on the lower mold 42-2 side is formed deeper than the recess 44-1 of the upper mold 42-1.

  The upper mold 42-1 is provided with a positioning protrusion 46 for positioning with respect to the lower mold 42-2, and the lower mold 42-2 is provided with a corresponding positioning recess 48. -1 and the lower mold 42-2 are positioned in the circumferential direction by the fitting of the positioning protrusions 46 and the positioning recesses 48.

The upper mold 42-1 also has molding recesses 50 for molding the supporting protrusions 40 and the inner surface layer 38C-1 in the upper end surface covering portion 38C of FIG. 3 at four positions separated by 90 ° in the circumferential direction. Is provided.
Similarly, the lower mold 42-2 is provided with a molding recess 50 for molding the supporting protrusion 40 and the inner surface layer 38D-1 in the lower end surface covering portion 38D of FIG.
The upper mold 42-1 is provided with an injection port 54 of a resin material that opens at the molding recess 50.
The upper mold 42-1 is provided with a passage 74 (see FIGS. 10 and 11) that communicates with the inlet 54 and penetrates the upper mold 42-1 vertically.

However, the position and the number of the injection ports 54 are merely examples, and it is not always necessary to open the molding recess 50. The cavity 68A for molding the inner surface layer 38A-1 in the outer peripheral covering portion 38A shown in FIG. Alternatively, the injection port 54 may be provided in the cavity 68B for molding the inner surface layer 38B-1 in the inner peripheral covering portion 38B.
Further, it is not always necessary to provide the injection port 54 in the upper mold 42-1. For example, the passage 74 is connected from the upper mold 42-1 to the lower mold 42-2 and the injection mold 54 is provided in the lower mold 42-2. Also good. Considerations such as allowing the resin to flow so that the coil 14 is not easily exposed, placing weakly strong parts such as welds (resin joints) where stress is small, and making it easier to remove products and runners from the mold. The position and number of inlets can be determined.

On the other hand, in the lower mold 42-2, gaps for forming the intermediate insulating layer 20 of FIG. 1 are formed between the upper coil 14-1 and the lower coil 14-2 at four positions separated by 90 ° in the circumferential direction. A plate-like spacer 56 for generating 70 (see FIG. 12) is provided so as to be able to enter and exit in the radial direction, that is, to be slidable.
The spacing and number of the spacers 56 are merely examples. If the amount is too large, the structure of the mold becomes complicated, resulting in an increase in size and cost. If the number is small, the gap 70 cannot be stably held. Therefore, the number of spacers may be determined to be as small as possible within a range where the gap 70 can be stably held.

As shown in FIG. 8, the lower mold 42-2 is provided with a slide groove 58 for sliding movement, and a spacer 56 is slidably fitted therein.
Specifically, the lower die 42-2 is provided with a notch 62, a slide groove 58 is provided at the bottom thereof, and a spacer presser 64 that forms a part of the lower die 42-2 is fitted into the notch 62. It is. The spacer presser 64 prevents the spacer 56 from being detached from the slide groove 58.

Each spacer 56 is provided with a stopper 60 that protrudes upward from its upper surface.
The stopper 60 serves to define the forward end and the backward end when the spacer 56 moves forward and backward (withdraw).
Specifically, the spacer presser 64 is provided with a bottomed long hole 66 extending in the radial direction, and the stopper 60 can be moved in the long hole 66 and is shown in FIG. Thus, the stopper 60 contacts the radially inner wall of the long hole 66 to define the forward end of the spacer 56, and as shown in FIG. 8 (B), the stopper 60 contacts the radially outer wall. The receding end (retraction end) of the spacer 56 is defined by hitting.

  FIG. 9 shows a state in which each spacer 56 is pushed inward in the radial direction until reaching the forward end (however, in FIG. 9, the upper coil 14-1 is omitted).

  In FIG. 10, the coil 14 is set in the primary mold 42, and each of the four spacers 56 is moved forward (pushing movement), and the spacers 56 are moved between the upper coil 14-1 and the lower coil 14-2. The gap 70 is inserted between the upper coil 14-1 and the lower coil 14-2.

FIG. 11A and FIG. 12A are enlarged views of the main part.
Among these, FIG. 11 (A) is a cross-section passing through the molding recess 50, and FIG. 12 (A) is a cross-section passing through a portion other than the molding recess 50. It is shown enlarged.
As shown in the drawing, with the coil 14 set in the primary mold 42, a cavity 68 for the primary molded body 38-1 shown in FIG.
Further, a gap 70 is formed between the upper coil 14-1 and the lower coil 14-2 in a state where each spacer 56 is moved to the forward end.
In this state, a thermoplastic resin material is injected from the injection port 54 through the passage 74 shown in FIGS. 10 and 11 to fill the cavity 68 and the gap 70.

At this time, the spacer 56 that has been moved to the forward end is moved backward by being pushed by the flow pressure of the resin material.
The space generated by the retreat is filled with a resin material, and finally the resin material is filled between the upper coil 14-1 and the lower coil 14-2, and then the intermediate insulating layer is formed by subsequent cooling. 20 and the primary molded body 38-1 are molded in a state of being integrally connected.
Here, when the lubricant is applied to the spacer 56 in advance when the coil 14 is set on the primary molding die 42, the insulating film of the wire may be damaged when the spacer 56 slides. Can be prevented.
The material of the spacer 56 can be steel, copper and copper alloy, aluminum and aluminum alloy, etc., but if it is softer than the coil wire, it is more suitable from the viewpoint of preventing the coil wire from being damaged or deformed. is there. Here, an aluminum alloy was used.

In the molding of the primary molded body 38-1, as shown in FIG. 13B, the supporting protrusion 40 has an outer peripheral protrusion 76 that protrudes upward in a rib shape along the outer peripheral edge. Molded.
As shown in FIG. 11, the upper mold 42-1 is formed with an annular recess 72 for the outer peripheral protrusion 76.
As will be described later, the outer peripheral protrusion 76 of the supporting protrusion 40 has a shape slightly protruding from the outer surface position of the outer surface layer 38C-2 when the secondary molded body 38-2 is formed.
This also applies to the support protrusion 40 in the lower end surface covering portion 38D of FIG. 3, and the outer peripheral protrusion 76 is simultaneously formed along the outer peripheral edge.
For this purpose, an annular recess 72 is also provided on the lower mold 42-2 side.

In this embodiment, positional deviation and deformation of the coil 14 during primary molding are prevented as follows. This point will be described in detail below with reference to FIGS.
The upper mold 42-1 of the primary molding die 42 has a coil pressing portion 42A-1 for pressing the outer peripheral surface of the upper coil 14-1, and a coil pressing portion 42B-1 for pressing the inner peripheral surface. The lower mold 42-2 has a coil pressing portion 42A-2 for pressing the outer peripheral surface of the lower coil 14-2 and a coil pressing portion 42B-2 for pressing the inner peripheral surface. However, the coil pressing portions 42A-1 and 42A-2 are not provided with a coil pressing portion in a portion connected to the molding recess 50 because it is necessary to secure a resin flow path with the molding recess 50.
Here, for example, the smaller the clearance between the outer peripheral surface of the upper coil 14-1 and the coil pressing portion 42A-1, the higher the positioning accuracy. However, when the coil is set and the die is closed, the insulation coating of the wire is used. Since there is a risk of scratching, it is preferable to provide a slight clearance (about ¼ of the thickness of the inner surface layer 38A-1 in the outer peripheral covering portion 38A). Further, it is more preferable to provide a slope or chamfer on the opening side as a guide. Further, the pressing amount in the axial direction of the coil 14 of the coil pressing portion 42A-1 may be at least 1 mm in order to stably position the coil. Conversely, the upper limit of the presser foot may be determined as appropriate from the required creepage distance. Here, the amount of presser foot was 2 mm.
The same applies to the other coil retainers 42A-2, 42B-1, and 42B-2.

If these coil retainers 42A-1, 42A-2, 42B-1, and 42B-2 are not provided and the cavities 68A and 68B are formed over the entire axial length of the coil 14, the radial direction There is no portion to support the coil, and the position of the coil is shifted or locally deformed in the mold due to the injection pressure of the resin at the time of injection molding, and the inner surface layer 38A-1 or inner periphery coating in the outer periphery coating portion 38A In the inner surface layer 38B-1 in the portion 38B, the coil may be partially exposed.
Of course, the coil covering 16 using the primary coil covering 16A with incomplete coating is repeatedly subjected to thermal load and mechanical load even if the secondary molded body 38-2 is normally coated. Even if it is not exposed, the creepage distance between the upper and lower coils is insufficient at the stage of shipping inspection, and there is a problem of rare shorts such as corona discharge, which cannot be a normal product.

On the other hand, as a constraint in the coil axis direction, the upper mold 42-1 of the primary molding die 42 has a coil pressing portion 42C-1 for pressing the upper end surface of the upper coil 14-1, and the lower mold 42- 2 has a coil pressing portion 42D-2 for pressing the lower end surface of the lower coil 14-2.
Here, the smaller the clearance between the upper end surface of the upper coil 14-1 and the coil pressing portion 42C-1 and the lower clearance between the lower coil 14-2 and the coil pressing portion 42D-2, the smaller the positioning. Although the accuracy is improved, there is a possibility that the insulating coating of the wire may be damaged at the portion in contact with the spacer 56 at the time of mold clamping when the coil having the upper limit of dimensional tolerance of the wire is used. Therefore, it is preferable to provide a slight clearance (0.1 to 0.2 mm) here as well.

14 to 20 specifically show the contents of secondary molding for molding the secondary molded body 38-2 in the resin coating layer 38. FIG.
Among these, FIGS. 14-15 has shown the structure of the secondary shaping | molding die.
In FIG. 14, reference numeral 78 denotes a secondary mold, and this secondary mold 78 has an upper mold 78-1 and a lower mold 78-2.
Each of the upper mold 78-1 and the lower mold 78-2 has a 1 after the primary molding shown in FIG. 14, specifically, the coil 14, the intermediate insulating layer 20, and the primary molded body 38-1. Recesses 80-1 and 80-2 for accommodating the secondary coil covering body 16A are provided.
Again, the recess 80-2 is formed deeper than the recess 80-1.

  The upper mold 78-1 is provided with a positioning convex portion 82, and the lower mold 78-2 is provided with a positioning concave portion 84. By fitting these positioning convex portions 82 to the positioning concave portion 84, 78-1 and lower mold 78-2 are positioned in the circumferential direction.

The upper die 78-1 is provided with a circular and ring-shaped positioning recess 86 for fitting the outer peripheral protrusion 76 of the supporting protrusion 40 of the upper end surface covering portion 38C in the primary molded body 38-1. Yes.
Similarly, the lower die 78-2 is also provided with a circular and ring-shaped positioning recess 86 for fitting the outer peripheral protrusion 76 of the supporting protrusion 40 in the lower end surface covering part 38D.
These positioning recesses 86 have a function of positioning the primary coil covering body 16A when it is set.

Further, the upper die 78-1 is provided with resin material injection ports 88 at four positions spaced by 45 ° in the circumferential direction from the positioning recess 86, and communicated with these injection ports 88 in an upper state 78-. 1 is provided with a passage 92 (see FIG. 19) penetrating in the vertical direction in the figure.
However, the position and number of the injection ports 88 are merely examples. For example, a cavity 90A for forming the outer surface layer 38A-2 in the outer peripheral covering portion 38A shown in FIG. 19 and / or the outer surface layer 38B in the inner peripheral covering portion 38B. The injection port 88 may be provided in the cavity 90B for molding -2.
Further, it is not always necessary to provide the injection port 88 in the upper die 78-1, and for example, the passage 92 is connected from the upper die 78-1 to the lower die 78-2, and the injection port 88 is provided in the lower die 78-2. Also good. Where the stress is small in a weakly strong part such as a weld (resin merging part) where the resin flows so that the primary coil covering 16A (the coil 14 or the primary molded body 38-1) is not easily exposed. The position and number of inlets may be determined in consideration of the arrangement and easy removal of products and runners from the mold.

As a matter of course, the coil covering 16 incompletely covered with the secondary molded body 38-2 is repeatedly exposed to a thermal load and a mechanical load even if the primary molded body 38-1 is normally coated. Even if it is not, dielectric breakdown from the exposed part occurs at the stage of shipping inspection, and it cannot be a normal product.
In addition, as the number of the injection ports 88 increases, the generation of welds increases, and the possibility that the position of the weld overlaps with a position where a large tensile stress is applied increases. The weld has a risk of causing cracks due to repeated thermal load or mechanical load, and when cracks occur in the secondary molded body 38-2, there is a possibility that dielectric breakdown from this part occurs.

FIG. 15 shows the operation when the primary coil covering body 16 </ b> A is set on the secondary mold 78.
As shown in FIGS. 15A and 15B, when the primary coil covering body 16A is set so as to be sandwiched between the lower die 78-2 and the upper die 78-1, as shown in FIG. As shown, the outer peripheral protrusions 76 of the upper and lower supporting protrusions 40 in the figure in the primary molded body 38-1 are fitted into the positioning recesses 86 of the upper mold 78-1 and the lower mold 78-2. The secondary coil covering body 16 </ b> A is positioned at a predetermined position with respect to the secondary mold 78.

  In other words, the primary coil covering body 16A is positioned so that the outer peripheral protrusions 76 of the supporting protrusions 40 fit into the corresponding positioning recesses 86 of the upper die 78-1 and the lower die 78-2. Thus, when the upper die 78-1 and the lower die 78-2 are closed, the primary coil covering body 16A is positioned at a predetermined position with respect to the secondary molding die 78 via the supporting protrusions 40. The

FIG. 15C shows a state where the primary coil covering body 16 </ b> A is positioned in the secondary mold 78 by fitting the outer peripheral protrusion 76 into the positioning recess 86 in this way.
At this time, the primary coil covering body 16A is supported by the supporting protrusions 40 so as to be lifted from the forming surface of the secondary forming die 78, and as shown in FIGS. A cavity 90 for the secondary compact 38-2 surrounding 16A is formed.
Here, since the supporting protrusions 40 are provided on both the upper end surface and the lower end surface of the coil 14, the coil 14 is concretely specified by the secondary forming die 78 in a state where the secondary forming die 78 is closed. In this case, the primary coil covering body 16A can be gripped from both the upper and lower sides via the supporting projections 40, and the coil 14, that is, the primary coil covering body 16A can be stably held and restrained.

As shown in enlarged views in FIGS. 15B and 15C, each of the upper die 78-1 and the lower die 78-2 is covered with a primary coil in a circular ring around the positioning recess 86. A forming projection 89 that protrudes toward the body 16A is provided.
Here, the outer peripheral surface of the forming projection 89 is an inclined surface that increases in diameter toward the root side over the entire periphery.
The function of the molding projection 89 will be described later.
FIG. 16 shows a state in which the primary coil covering body 16A is set on the lower die 78-2 in a plan view.

18 (A) and 19 (A) show an enlarged view of the main part in a state where the primary coil covering body 16A is set in the secondary mold 78. FIG.
In the state shown in these drawings, when the same resin material as that of the primary molded body is injected from the injection port 88 through the passage 92 shown in FIG. 19A, the injected resin material becomes a cavity as shown in FIG. 19B. 90 filled.
Thereafter, by cooling this, the secondary molded body 38-2 that surrounds and covers the coil 14 together with the primary molded body 38-1 (except for the supporting projection 40) is integrally molded.

FIG. 20 shows the coil covering 16 obtained in this way.
As shown in FIG. 20B, at the stage of forming the secondary molded body 38-2, the outer peripheral surface of the support protrusion 40 and the outer surface layers 38C-2 and 38D-2 around it are joined to each other. Is done.
In addition, at the stage where the secondary molded body 38-2 is molded, a circular recess 94 is molded along the boundary between the support protrusion 40 and the outer surface layer 38C-2 (38D-2).
The recess 94 is formed by the forming projection 89 of FIG.

  If the supporting protrusion 40 and the outer surface layers 38C-2 and 38D-2 around the upper end surface covering portion 38C and the lower end surface covering portion 38D are simply joined by injection molding, repeated thermal loads and mechanical When the load is applied to the resin coating layer 38 and the resin coating layer 38 repeatedly expands and contracts, the joint may be peeled off.

However, the outer surface layers 38C-2 and 38D-2 are laminated and superposed on the inner surface layers 38C-1 and 38D-1 formed inside the supporting projection 40 and in a larger shape in plan view than this. For this reason, even if the joint is peeled off, it does not directly lead to dielectric breakdown.
However, if the bonding peeling occurs and a minute gap is generated, water vapor may enter the resin coating layer 38 through the gap. The invading water vapor causes condensation inside, which may lead to dielectric breakdown.
Therefore, here, the following processing is performed on the coil covering 16.
21 and 22 show specific contents of the processing.

In the figure, reference numerals 96-1 and 96-2 denote welding jigs, each having a jig body 98 and four leg portions 100 protruding therefrom.
As shown in FIG. 22A, a pressing portion 102 is provided at each tip of the leg portion 100.
These welding jigs 96-1 and 96-2 have a built-in heater, and the pressing portion 102 is held in a heated state equal to or higher than the melting temperature of the resin.

Here, when the outer peripheral protrusions 76 of the supporting protrusions 40 are pressed by the pressing portions 102 of the respective leg portions 100 of the pair of welding jigs 96-1 and 96-2, the outer peripheral protrusions 76 are brought into a molten state by heating. Then, the resin that has been crushed and melted enters the annular recess 94 and fills it, and at the same time, the supporting protrusion 40 and the outer surface layers 38C-2 and 38D-2 are welded at their boundary portions.
As a result, it is possible to effectively prevent a phenomenon in which minute gaps are generated by bonding and peeling between the supporting protrusions 40 and the outer surface layers 38C-2 and 38D-2 around the protrusions, and water vapor enters the resin coating layer 38 from there. it can.

  It should be noted that the above-described outer peripheral protrusion 76 is simultaneously formed on the supporting protrusion 40, is melted by heating and pressurizing, and is welded to the surrounding outer surface layers 38C-2 and 38D-2. In some cases, the supporting protrusions 40 with or without the outer peripheral protrusions 76 are protruded from the outer surface layers 38C-2 and 38D-2, and the protruding portions are scraped and removed later. Anyway.

Here, the case where welding is not essential is, for example, the temperature of the resin injected at the time of the secondary molding, and the primary molded body 38-1 is naturally re-melted, and the primary molded bodies 38-1 and 2-2. This is a case where the next molded body 38-2 is integrated. In particular, when the resin used for primary molding is lower than the melting point of the resin used for secondary molding, remelting tends to occur.
In addition, a large creepage surface is necessary to prevent an electric shock between the coil 14 and the outside by keeping the shape of the portion around the supporting protrusion 40 of the inner surface layers 38C-1 and 38D-1 in plan view. Even when the distance can be secured, welding is not essential.

In this embodiment, the coil covering manufactured as described above is then integrated with the core 12 to manufacture the reactor 10.
23 and 24 show a process for manufacturing the reactor 10 as described above.
In FIG. 23, reference numeral 104 denotes a primary mold for molding the primary molded body 12-1 in the core 12, and has an upper mold 104-1 and a lower mold 104-2.
The upper mold 104-1 is provided with a passage 106 and an injection port 108.
The upper mold 104-1 and the lower mold 104-2 form a cavity 110 corresponding to the primary molded body 12-1 between them in a clamped state.

In this embodiment, a thermoplastic resin material is injected into the cavity 110 from the inlet 108 through the passage 106, and the cavity 110 is filled with the resin material.
Thereafter, this is cooled and solidified, whereby the primary molded body 12-1 in the core 12 is obtained.
As shown in FIG. 2, the primary molded body 12-1 has a container shape having an opening 28 at the upper end.
Therefore, the coil covering body 16 obtained as described above is fitted into the primary molded body 12-1 and held there.
And in this state, this is set to the secondary shaping | molding die 112 shown in FIG.
At this time, the lower mold 112-2 comes into contact with the outer peripheral surface of the primary molded body 12-1, positions the primary molded body 12-1 together with the coil covering body 16 in the radial direction, and restrains it.
Further, it contacts the lower surface of the primary molded body 12-1 and supports it upward.

In this state, the same resin material as that of the primary molded body 12-1 is injected from the inlet 118 through the passage 116 provided in the upper mold 112-1 into the cavity 114 formed inside the secondary mold 112. Is filled into the cavity 114.
Thereafter, by cooling and solidifying the secondary molded body 12-2, the secondary molded body 12-2 is joined to the primary molded body 12-1 and the coil covering body 16 at the same time. Reactor 10 is obtained.

  As described above, the coil covering body 16 of the present embodiment has the outer periphery covering portion 38A and the inner periphery covering portion 38B of the resin covering layer 38 made of an injection molded body of a thermoplastic resin that entirely encloses the coil 14 from the outside. As a laminated structure of the inner surface layers 38A-1 and 38B-1 extending through the end of the insulating layer 20 and the outer surface layers 38A-2 and 38B-2 on the outer side, the inner surface layers 38A-1 and 38B-1 are integrated. Since the intermediate insulating layer 20 is formed by injection molding, the end face of the intermediate insulating layer 20 is not likely to be peeled off from the outer peripheral covering portion 38A and the inner peripheral covering portion 38B as in the conventional coil cover. Therefore, the insulation performance by the intermediate insulating layer 20 is impaired by the bonding separation, and spark discharge and corona discharge are generated between the coil blocks 14-1 and 14-2 stacked with the intermediate insulating layer 20 in between. Raresho It is possible to solve the problems that cause the door.

  Moreover, in the manufacturing method of this embodiment, the resin coating layer 38 is divided into a primary molding step and a secondary molding step, and injection molding is performed. In the primary molding step, the coil block 14-1 and the coil block 14-2 are A slidable plate-like spacer 56 is sandwiched between them, a gap 70 is formed between them, and a resin material is injected while the spacer 56 is drawn and moved, and the resin material is injected into the cavity 56 and the gap 70, Furthermore, since the space generated by the pull-in movement of the spacer is filled, the inner surface layers 38A-1 and 38B-1 and the intermediate insulating layer 20 can be satisfactorily integrally injection molded.

  By such a method, the intermediate insulating layer 20 is separated from the outer peripheral covering portion 38A and the inner peripheral covering portion so that the boundary between the intermediate insulating layer 20 and the outer peripheral covering portion 38A and the inner peripheral covering portion 38B, which are cross covering portions, does not become a joint. It can be easily formed in a form integrally connected to the portion 38B.

  In the manufacturing method of the present embodiment, the spacer is automatically drawn and moved by the flow pressure of the injected resin, so that the spacer 56 at the protruding position (extrusion position) is automatically drawn and moved at an appropriate timing. Can be made. In addition, the configuration of the molding apparatus can be simplified.

  In this embodiment, the outer surface layers 38A-2, 38B-2, 38C-2, 38D of the outer periphery covering portion 38A, the upper end surface covering portion 38C, the inner periphery covering portion 38B, and the lower end surface covering portion 38D of the resin coating layer 38 are provided. -2 is a seamless and integrally formed body, so that even if the resin coating layer 38 repeatedly expands and contracts due to repeated application of thermal load or mechanical load to the coil cover 16, the conventional coil It is possible to prevent the resin coating layer from being peeled off at the joint portion of the joint as in the case of covering and creating a gap, and thus the problem that the insulation performance is impaired due to the occurrence of the gap can be solved, Performance reliability can be increased.

Figures 25-28 illustrate other embodiments of the present invention.
In this embodiment, the upper end surface covering portion 38C of the resin coating layer 38 in the coil covering body 16 does not have the supporting protrusion 40 and the inner surface layer 38C-1 unlike the above embodiment, and the upper end surface covering portion 38C. Is different from the above embodiment in that it is composed of an outer surface layer 38C-2 single layer forming the outer surface.
Other configurations are the same as those in the first embodiment.

  FIG. 26A shows the primary coil covering body 16A after forming the primary molded body 38-1 in the resin coating layer 38. FIG. Further, (B) represents the coil cover 16 after the secondary molded body 38-2 is molded.

FIG. 27 shows a main process of primary molding in the resin coating layer 38.
Here, the coil 14 is set in the primary mold 42 in the upside down direction from the state shown in FIG.
At this time, a cavity 68 for the primary molded body 38-1 is formed around the coil 14.
However, as is clear from the comparison with FIG. 11, here, the molding space for the support protrusion 40 is formed only on the upper mold 42-1 side, and the support protrusion 40 is formed on the lower mold 42-2 side. The molding space is not formed.
In this embodiment, the resin material is injected in the state shown in FIG. 27A and filled into the cavity 68, and then cooled and solidified, whereby the primary molded body 38-1 is brought together with the intermediate insulating layer 20. Molded integrally.

FIG. 28 shows a main process of the secondary molding of the resin coating layer 38.
Here, the secondary coil body 16A is set around the primary coil cover body 16A in a state where the primary coil cover body 16A is set on the secondary mold 78 and the upper coil 14-1 and the lower coil 14-2 are set upside down. A cavity 90 for 38-2 is formed.
At this time, the primary coil covering body 16A is in a state in which the supporting protrusions 40 protrude downward from the lower end surface of the primary coil covering body 16A. It is supported upward from.
At the same time, the primary coil covering body 16 </ b> A is positioned with respect to the secondary mold 78 by the outer peripheral protrusion 76 of the support protrusion 40.

In this state, the same resin material as the primary molded body 38-1 is injected into the cavity 90, filled, and then cooled and solidified, whereby the secondary molded body 38-2 is molded. At the same time, the secondary molded body 38-2 is joined to the primary molded body 38-1 and the coil 14 by injection molding.
Here, the supporting protrusion 40 is only in the lower die 78-2 and not in the upper die 78-1, but by providing the resin material injection port 88 in the upper die 78-1, the primary pressure is increased by the injection pressure. The coil covering body 16A is pressed against the lower mold, and the primary coil covering body 16A can be injection-molded without being lifted.
After that, it is the same as that of the first embodiment in that the outer peripheral protrusion 76 is welded to the outer surface layer 38D-2 in the lower end surface covering portion 38D by heating and pressing.
In this embodiment, since the upper end surface covering portion 38C is a single layer of the outer surface layer 38C-2, the upper end surface covering portion 38C can be formed thin, thereby improving heat dissipation.
Moreover, since the joining / welding location is only the lower end surface covering portion 38D, the possibility of peeling can be reduced to half.

29 and 30 show still another embodiment of the present invention.
In this example, the inner surface layer 38B-1 in the inner peripheral covering portion 38B is further omitted from the primary molded body 38-1 as compared with the second embodiment shown in FIGS. That is, the inner peripheral covering portion 38B is composed of a single layer of the outer surface layer 38B-2.
Also in this embodiment, as shown in FIG. 30, the coil terminal 22 protrudes radially outward from the upper coil 14-1 and the lower coil 14-2.

When the coil terminal 22 protrudes radially outward from the upper coil 14-1 and the lower coil 14-2, the potential difference at the innermost circumference between the upper coil 14-1 and the lower coil 14-2 is small. .
Therefore, even if the inner peripheral end of the intermediate insulating layer 20 is peeled off from the inner peripheral covering portion 38B, it does not cause a big problem.

Therefore, in this embodiment, the inner surface layer 38B-1 in the inner peripheral covering portion 38B is omitted, and the inner peripheral end of the intermediate insulating layer 20 is directly against the outer surface layer 38B-2 of the inner peripheral covering portion 38B, that is, the inner peripheral covering portion. It joins with the part 38B at the time of injection molding.
In this case, the thickness of the inner periphery covering portion 38B can be reduced as compared with the case of the two-layer laminated structure, and the heat dissipation can be increased accordingly.
In addition, since the entire inner peripheral surface of the coil is constrained by the mold during the primary molding, the positioning at the time of injection molding becomes higher.

Next, FIG. 31 shows still another embodiment of the present invention.
In this example, although not shown, the coil terminal 22 is protruded radially inward from the upper coil 14-1 and the lower coil 14-2.

  In the embodiment of FIGS. 29 and 30, the inner surface layer 38B-1 on the inner peripheral covering portion 38B side is omitted in the primary molded body 38-1, but here the outer surface layer is disposed on the inner peripheral covering portion 38B side. While the inner surface layer 38B-1 is provided in a laminated state together with 38B-2, the inner surface layer 38A-1 is omitted on the outer periphery covering portion 38A side, and the outer periphery covering portion 38A is formed as a single layer of the outer surface layer 38A-2.

In the case shown in FIG. 31, since the coil terminal 22 protrudes radially inward, the potential difference at the outermost periphery between the upper coil 14-1 and the lower coil 14-2 is small. The outer peripheral edge of the insulating layer 20 is joined by injection molding so that the outer peripheral edge is attached to the outer peripheral covering portion 38A.
In this embodiment, since the outer periphery covering portion 38A is a single layer of the outer surface layer 38A-2, the outer periphery covering portion 38A can be formed thin, and the heat dissipation at the outer periphery covering portion 38A can be enhanced.

About the reactor 10 shown in FIGS. 1-24, the following durability tests were done and evaluation of each characteristic, such as an insulation resistance, a withstand voltage, a rare short, was performed.
In addition, the same test and evaluation were performed as a comparative example for the reactor shown in FIG.
The specific configuration of the reactor was as follows.

(A) Reactor configuration In each of the examples and comparative examples, a soft magnetic powder having a composition of Fe-6.5Si (mass%) is used as the core, and the core, the resin coating layer, and the thermoplastic resin of the intermediate insulating layer are used. PPS resin was used here (in this case, a linear PPS resin having a product name of H-1G manufactured by DIC Corporation, and 200 μm ground powder was used).

As the soft magnetic powder, gas spray powder sprayed with argon gas was used, and powder heat treatment was performed in hydrogen at 750 ° C. for 3 hours for the purpose of preventing oxidation and reducing action.
In addition, assuming that the core is used in an alternating magnetic field of 1 to 50 kHz, the soft magnetic powder used is a powder obtained by sieving to 250 μm or less after powder heat treatment.
The soft magnetic powder and the resin material were kneaded with a biaxial kneader to be pelletized to prepare a compound.
The compound was heated at about 300 ° C. by a horizontal in-line screw injection molding apparatus, injected into a mold having a preheating temperature of 150 ° C. as a molten state, and cooled to form a core.
The coil uses a flat copper rectangular wire with an insulating coating made of polyamideimide resin (film thickness is 20-30 μm) (wire size is 0.85 mm thickness, 9 mm width). The lower coil and the lower coil are stacked in two stages, and the coil is continuously wound so that the inner peripheral side is in a continuous connection state (FIG. 4C).

The winding direction of the upper coil and the lower coil is such that the upper coil is wound in the opposite direction with respect to the lower coil so that the current flows in the same rotational direction when energized (that is, the generated magnetic field does not cancel each other). How to wind.
The dimensions were such that the inner diameter of the coil was 47 mm and the number of turns was 18 for both the lower and upper coils, for a total of 36 turns.

As the material of the resin coating layer of the coil coating body, the same PPS resin was used for both the primary molded body and the secondary molded body. In addition, 40 mass% of glass fiber and carbon fiber are added to this PPS resin. However, since the addition of a large amount of carbon fiber impairs the insulating properties, the addition of a small amount is limited in view of the balance with mechanical strength and linear expansion coefficient.
This was also prepared as a pellet-like compound in the same manner as the core material, and injection molded by a vertical in-line screw type injection molding apparatus. The melting temperature and mold temperature were the same as the core material.

After the primary and secondary forming steps of the coil cover, a supporting protrusion welding step was performed. The material of the welding jig was beryllium copper so that the temperature could be maintained at 300 ° C. Using this jig, the outer peripheral protrusion was melted and integrated so as to be in the state of FIGS. 22A to 22B by applying pressure for 1 second.
The core encloses the coil in an embedded state without a gap, and the core has an outer diameter of φ90 mm and a core height of 40.5 mm.
The axial center of the core, the axial center of the coil, and the axial center of the core and the axial center of the coil are arranged so as to coincide with each other.

(B) Endurance test An endurance test was conducted to determine whether or not it could be stably withstood in a long-term actual use environment. In the endurance test, a mechanical load and an environmental load were inserted several times between the thermal loads in order to simulate a condition in which a thermal load, a mechanical load, and an environmental load are applied and exposed. Thermal load is a thermal shock test to simulate rapid start-up from a low-temperature environment such as below freezing point, continuous energization test to simulate continuous operation at high load, and intermittent operation at high and low loads. Three types of intermittent energization tests were performed. The mechanical load was simulated by a vibration test, and the environmental load was simulated by a constant temperature and humidity test. More specific conditions are as follows.
<Thermal shock test>
The thermal shock test was conducted as follows.
The reactor was housed inside a 5 mm thick aluminum case (reactor case) 250 having a container portion 252 and a lid portion 254 shown in FIG. 33, and the aluminum case 250 and the reactor were fixed with silicone resin.
Then, the reactor containing the case 250 (hereinafter abbreviated) is put in a thermal shock test apparatus, the low temperature bath is set to −40 ° C., the high temperature bath is set to 160 ° C., and low temperature exposure and high temperature exposure are alternately repeated for 1000 cycles (low temperature exposure). 1 cycle and 1 cycle of high temperature exposure). Each exposure time was 2 hours after the reactor internal temperature reached the set temperature. However, the constant temperature and humidity test was performed after performing the following vibration test every 100 cycles and finally.
[Test apparatus]: Thermal shock test apparatus ESPEC Corporation TSA-72EL-A was used.

<Continuous current test>
The continuous energization test was conducted as follows.
A cased reactor electrically connected to the step-up chopper circuit was fixed on a water-cooled plate. At this time, the heat conduction grease was thinly applied between the water cooling plate. And the reactor with this water cooling plate was put into the thermostat.
The boost chopper circuit is driven so as to boost the voltage from 300 V to 600 V under the conditions of the superposed current 75 A and the switching frequency 10 kHz, and it is in a thermally steady state (a state where the internal temperature of the core and the cooling water temperature do not change with time). I was ready to drive. The cooling water flowing through the cooling plate was controlled to flow at 60 ° C. and 10 liters per minute with a chiller (constant temperature water circulation device). The constant temperature furnace was controlled so that the atmospheric temperature in the furnace was 110 ° C.
And it was made to drive for 1000 hours, maintaining a steady state. However, after performing the following vibration test every 100 hours and finally, a constant temperature and humidity test was performed.

<Intermittent test>
The intermittent energization test was conducted as follows.
The cased reactor electrically connected to the step-up chopper circuit was placed in a low temperature thermostat and allowed to stand until the entire reactor reached a constant temperature. At this time, the in-furnace atmosphere temperature of the low-temperature thermostat was controlled to be −40 ° C.
The step-up chopper circuit was driven to increase the voltage from 300 V to 600 V under the condition of a switching frequency of 10 kHz, and the current was applied until the maximum coil temperature (center temperature) reached 160 ° C. Here, the superimposed current was controlled so that the temperature of the coil reached 160 ° C. in 10 minutes from the start of energization. When the coil temperature reached 160 ° C., the energization was stopped and the reactor was left until the entire reactor reached −40 ° C. again.
A series of this energization start, energization stop, and cooling standing was defined as one cycle, and this was repeated 1000 cycles. However, the constant temperature and humidity test was performed after performing the following vibration test every 100 cycles and finally.

<Excitation test>
The vibration test itself was not performed alone, but was performed during and at the end of a stress test such as a thermal shock test, a continuous energization test, and an intermittent energization test. In order to verify whether or not the reactor component has sufficient strength, and in the stress test, if there was a broken part, it was carried out for the purpose of mechanical expansion.
The vibration test was performed as follows.
One surface of a dice-shaped regular hexahedron jig was fixed to a single-axis vibration device, and three reactors containing cases were fixed to three adjacent surfaces of the jig, respectively. At this time, each of the reactors was fixed to the jig in such a direction that vibrations were applied in three directions of up and down, left and right, and front and rear. When the vibration test is performed in this state, each reactor is subjected to vibration in one direction.
Next, a second test was performed with the orientation changed and fixed, and a third vibration test was performed with the last orientation fixed to obtain a reactor in which vibration was applied in three directions.
Excitation conditions were logarithmic sweep from acceleration 10G / frequency 5Hz to acceleration 5G / frequency 200Hz over 30 minutes, and then logarithmic sweep from acceleration 5G / frequency 200Hz to acceleration 10G / frequency 5Hz over 30 minutes.
[Test apparatus]: Excitation apparatus Emic Co., Ltd. F-06000BM / FA was used.

<Constant temperature and humidity test>
The constant temperature / humidity test itself was not performed alone, and the constant temperature / humidity test was performed after the vibration test was performed during and at the end of the stress test such as a thermal shock test, a continuous current test, and an intermittent current test. This constant temperature and humidity test was performed for the purpose of mechanically expanding the vibration test and allowing water vapor to penetrate into the damaged part if there was a broken part in the stress test.
The constant temperature and humidity test was performed as follows.
Conditions were maintained at a temperature of 85 ° C. and a relative humidity of 85% RH for 100 hours per time.
[Test apparatus]: Constant temperature and humidity chamber Yamato Scientific Co., Ltd. IG400 was used.

(C) Evaluation test The evaluation test was carried out twice before and after the durability test. A plurality of samples that passed the initial evaluation test were prepared, and a predetermined number of samples were extracted from the samples and put into the durability test. An evaluation test was performed again after the durability test, and the final pass / fail of the sample was determined. The determination method was as follows. The test order was performed in the order described below.

<Appearance inspection of cased reactor>
With the reactor in the case, the appearance was visually inspected to check for cracks and deformations.

<Insulation resistance>
The cased reactor was placed on an insulating plate, and one measuring probe of the measuring device was connected to the root of one coil terminal of the reactor, and the other measuring probe was connected to the aluminum case. And in that state, it supplied with electricity, DC1000V was applied for 1 minute, and the insulation resistance value at that time was measured. Also, unnecessary portions of the reactor terminals were cut out and insulated in advance to prevent unnecessary discharge.
The criterion for determination was a failure if the insulation resistance was 100 MΩ or less.
[Test apparatus]: Kikusui Electronics Co., Ltd. TOS5051A was used.

<Rare short test>
In the rare short test, by applying a high frequency voltage to the coil, the insulation of the insulation film between the windings of the coil wire rod and the insulation of the insulation coating between two (or more) coil blocks are inspected. To do.
The rare short test was conducted as follows.
Measurement is performed by placing a cased reactor on an insulating plate and placing one measuring probe of the measuring device at the base of one coil terminal of the reactor and the other measuring probe at the base of the other coil terminal of the reactor. Connected. A voltage having a peak value of 1500 V (volts) was applied between the terminals of the coil at 50 kHz for 5 minutes. Also, unnecessary portions of the reactor terminals were cut out and insulated in advance to prevent unnecessary discharge.
Judgment criteria were the presence or absence of spark discharge (flashover) and corona discharge. If there was, it was rejected.
Here, just because corona discharge (local breakdown discharge) has occurred, it cannot necessarily be said to be dielectric breakdown, but it is not possible because it is likely that dielectric breakdown will eventually occur at this site by continuous application of high-frequency voltage. Passed.
[Test apparatus]: COROXA-i XT-330PB33b was used.

<Withstand voltage test>
The withstand voltage measurement is performed in order to inspect the insulating property of the insulating coating at the part in contact with the outside of the coil coating.
The withstand voltage measurement was performed as follows.
In the measurement, a cased reactor was placed on an insulating plate, and one measuring probe of the measuring device was connected to the base of one coil terminal of the reactor, and the other measuring probe was connected to an aluminum case. Then, electricity was applied in this state, and a 50 or 60 Hz sine wave was gradually increased from 0 to 3750 V (volt) at the peak voltage, and held at 3750 V for 1 minute. Also, unnecessary portions of the reactor terminals were cut out and insulated in advance to prevent unnecessary discharge.
Judgment criteria were the presence or absence of spark discharge (flashover), and if it was present, it was rejected.
[Test apparatus]: Kikusui Electronics Co., Ltd. TOS5051A was used.

<Impulse withstand voltage test>
The impulse withstand voltage measurement is performed in order to inspect whether the insulation performance of the insulation coating at the portion in contact with the outside of the coated coil molded body and the insulation performance of the entire reactor satisfy the required spatial distance and creepage distance.
The impulse withstand voltage test was conducted as follows.
In the measurement, a cased reactor was placed on an insulating plate, and one measuring probe of the measuring device was connected to the base of one coil terminal of the reactor, and the other measuring probe was connected to an aluminum case. Then, electricity was applied in that state, and a 50 or 60 Hz sine wave was applied at a peak voltage of 9850 V (volts) for 60 milliseconds or more. Also, unnecessary portions of the reactor terminals were cut out and insulated in advance to prevent unnecessary discharge.
Judgment criteria were the presence or absence of spark discharge (flashover), and if it was present, it was rejected.
[Test apparatus]: Kikusui Electronics Co., Ltd. TOS5101 was used.

<Appearance inspection of reactor alone>
In the first evaluation test, the appearance was inspected before the case was embedded, and in the final evaluation test, the reactor was taken out from the case. Visual inspection was conducted to check for cracks and deformation.

(D) Results For each of the Examples and Comparative Examples in Table 1, nine cased reactors that passed the first evaluation test (that is, these correspond to products that passed the shipping inspection) were prepared. Three pieces each were put into a thermal shock test, a continuous energization test, and an intermittent energization test as durability tests. And the final pass / fail was judged by the evaluation test after an endurance test.

Of the two rejected products in the thermal shock test of the comparative example, the corona discharge in the rare short test was detected in the measured waveform and failed. When the generation site was examined by disassembling after the test, discharge traces were observed on the outer peripheral portion of the intermediate insulating sheet (site X in FIG. 35).
Corona discharge in the rare short test was detected in the measured waveform in one of the two rejected products in the continuous energization test of the comparative example, and failed. When the generation site was examined by disassembling after the test, discharge traces were observed on the outer peripheral portion of the intermediate insulating sheet (site X in FIG. 35).
Corona discharge in the rare short test was detected in the measured waveform in one of the two rejected products in the intermittent energization test of the comparative example and failed. When the generation site was examined by disassembling after the test, discharge traces were observed on the outer peripheral portion of the intermediate insulating sheet (site X in FIG. 35).
On the other hand, in the examples, the thermal shock test, the continuous energization test, and the intermittent energization test all passed.

Although the embodiment of the present invention has been described in detail above, this is merely an example.
For example, the present invention can be applied even when the coil is a flatwise coil and the upper coil, the middle coil, and the lower coil are stacked in three upper and lower stages.
In this case, each of the outer peripheral covering portion and the inner peripheral covering portion has a laminated structure of an inner surface layer and an outer surface layer, and two intermediate insulating layers that insulate between the upper and lower coils are injected to each inner surface layer. Integrate by molding.

The present invention is also applicable to a configuration in which, for example, as shown in FIG. 32, the coil 14 is an edgewise coil and the inner coil 14-3 and the outer coil 14-4 are overlapped in the radial direction. Is possible.
In this case, the intermediate insulating layer 20 is interposed between the inner coil 14-3 and the outer coil 14-4. In this case, the intermediate insulating layer 20 extends in the coil axis direction.

Therefore, in this case, at least one of the upper end surface covering portion (first end surface covering portion) 38C and the lower end surface covering portion (second end surface covering portion) 38D is used as the inner surface layer 38C-1 (or 38D-1) and the outer surface. There is no two-layer laminated structure with the layer 38C-2 (or 38D-2) (however, both are two-layer laminated structures in the figure), and the intermediate insulating layer 20 is integrated with the inner surface layer 38C-1 (or 38D-1). To injection molding.
In this case, when the coil terminal protrudes upward in the drawing, the upper end surface covering portion 38C has a two-layer laminated structure of the inner surface layer 38C-1 and the outer surface layer 38C-2, and intermediate insulation with respect to the inner surface layer 38C-1 is performed. Layer 20 is integrated by injection molding.

Conversely, when the coil terminal protrudes downward in the figure, the lower end surface covering portion 38D has a two-layer laminated structure of the inner surface layer 38D-1 and the outer surface layer 38D-2, and is integrated with the inner surface layer 38D-1. The intermediate insulating layer 20 is formed by injection molding.
Of course, both the upper end surface covering portion 38C and the lower end surface covering portion 38D have a two-layer laminated structure of an inner surface layer and an outer surface layer, and the intermediate insulating layer 20 is integrally formed with each of the inner surface layers 38C-1 and 38D-1. Injection molding can also be performed.

In the case of the example in the figure, the inner surface layer 38C-1 of the upper end surface covering portion 38C and the inner surface layer 38D-1 of the lower end surface covering portion 38D are continuously formed in the circumferential direction of 360 ° on the respective end surfaces. On the other hand, the supporting projections 40 are formed at four locations that differ by 90 ° in the circumferential direction, while the inner surface layer 38A-1 of the outer peripheral covering portion 38A and the inner surface layer 38B-1 of the inner peripheral covering portion 38B are unnecessary. It becomes.
If the injection port at the time of injection molding is arranged immediately above the gap for forming the intermediate insulating layer 20, the resin injected from the injection port is preferentially filled into the gap for forming the intermediate insulating layer 20 by the injection pressure. Therefore, there is an advantage that the spacer 56 described above can be eliminated.
In addition, this invention can be comprised and implemented with the form and aspect to which various changes were added in the range which does not deviate from the meaning.

14 Coil 14-1 Upper coil block 14-2 Lower coil block 16 Coil covering 20 Intermediate insulating layer 22 Coil terminal 38 Resin covering layer 38-1 Primary molded body 38A Outer periphery covering portion 38B Inner periphery covering portion 38C Upper end surface covering portion 38D Lower end surface covering portion 38A-1, 38B-1, 38C-1, 38D-1 Inner surface layer 38A-2, 38B-2, 38C-2, 38D-2 Outer surface layer 40 Supporting protrusion 42 Primary molding die 56 Spacer 68, 90, 110, 114 Cavity 76 Outer peripheral edge projection 78 Secondary mold 94 Recess

Claims (6)

The wire is wound in such a state that an insulating film is interposed between the wires, and a plurality of coil blocks are connected to each other with the intermediate insulating layer interposed in the height direction and / or radial direction that is the coil axis direction. A conductor coil having a shape of being coaxially overlapped with each other, an outer periphery covering portion that covers the outer peripheral surface of the coil, an inner periphery covering portion that covers the inner peripheral surface, and a first end surface that covers one first end surface in the axial direction. Covered in a state entirely enveloping from the outside with a resin coating layer made of an injection molded body of an electrically insulating thermoplastic resin, having a second end surface covering portion covering the end surface covering portion and the other second end surface in the axial direction A coil covering comprising:
Forming the intermediate insulating layer from a thermoplastic resin;
In addition, at least one of the outer covering portion, the inner covering portion, the first end face covering portion, and the second end face covering portion that crosses the intermediate insulating layer passes through the end of the intermediate insulating layer. A coil covering, wherein the intermediate insulating layer is formed by injection molding integrally with the inner surface layer as a laminated structure of the inner surface layer extending and the outer surface layer outside the inner surface layer. 2. The intermediate insulating layer according to claim 1, wherein the coil is a flatwise coil, and an upper coil block and a lower coil block are vertically stacked in the height direction, and the intermediate insulating layer is interposed between the upper coil block and the lower coil block. Is interposed in a state extending in the radial direction,
At least one of the outer peripheral covering portion and the inner peripheral covering portion serving as the cross covering portion has a laminated structure of the inner surface layer and the outer surface layer, and the intermediate insulating layer is integrally formed with the inner surface layer by injection molding. A coil covering body characterized by being formed. In Claim 2, the coil terminal protrudes radially outward from the upper coil block and the lower coil block, respectively.
The coil covering body, wherein the outer peripheral covering portion has a laminated structure of the inner surface layer and the outer surface layer, and the intermediate insulating layer is formed integrally with the inner surface layer by injection molding. In Claim 2, the coil terminal protrudes radially inward from the upper coil block and the lower coil block, respectively.
The coil covering body, wherein the inner peripheral covering portion has a laminated structure of the inner surface layer and the outer surface layer, and the intermediate insulating layer is formed integrally with the inner surface layer by injection molding. In producing the coil covering according to any one of claims 1 to 4,
The process of injection molding the resin coating layer is divided into a primary molding process and a secondary molding process,
In the primary molding step, a slidable plate-like spacer is sandwiched between the coil block and the coil block, and communicated with the cavity for molding the inner surface layer between the coil block and the coil block. Forming a gap for forming the intermediate insulating layer,
The resin material is injected while moving the spacer, and the resin material is filled into the cavity, the gap, and the space generated by the movement of the spacer, and the resin coating layer including the inner surface layer is primary molded. The body and the intermediate insulating layer are integrally formed by injection molding,
In the subsequent secondary molding step, the secondary molded body of the resin coating layer is injection molded in a state of wrapping the coil together with the primary molded body including the intermediate insulating layer and the inner surface layer, and the outer peripheral coating portion, A manufacturing method of a coil covering, comprising: forming an inner periphery covering portion, a first end face covering portion, and a second end face covering portion as a whole.   6. The method of manufacturing a coil covering according to claim 5, wherein the spacer is automatically drawn and moved by the flow pressure of the injected resin.

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