JP4751774B2 - Method for manufacturing reactor for voltage converter - Google Patents

Description

  The present invention relates to a method for manufacturing a reactor for a voltage converter and a reactor for a voltage converter, and in particular, a magnetic core provided with a gap having a predetermined width, and a ceramic material disposed in the core gap and bonded to the core. The manufacturing method of the reactor for voltage converters which manufactures the reactor for voltage converters provided with the core structure which has a gap member containing, and the reactor for voltage converters.

  A vehicle, for example, a hybrid (HV) automobile is provided with a voltage converter such as a boost converter that boosts the voltage of the battery by turning on and off the switch. In the voltage converter, a reactor in which a coil such as a copper wire is wound around a core that is a magnetic body such as an iron core is used.

  In a voltage converter reactor provided in a voltage converter, a core provided with a gap having a predetermined width is generally used. A magnetic gap is provided by the gap provided in the core to suppress a decrease in inductance in the voltage converter reactor.

  A gap member formed of a synthetic resin material or the like can be provided in the gap provided in the core. For example, Patent Document 1 discloses a reactor in which a gap member formed of a synthetic resin material such as a phenol resin or an epoxy resin is provided in a core gap.

JP 2000-353626 A

  When the gap member disposed in the gap of the core, which is a magnetic body, is formed of a synthetic resin material such as epoxy resin, the gap member is deformed by heat or the like because the thermal expansion coefficient of the synthetic resin material is large. The width of the gap provided in the core may change. If the width of the gap provided in the core changes, the inductance in the voltage converter reactor may not be kept constant.

  Therefore, a ceramic material or the like having a smaller coefficient of thermal expansion than that of the synthetic resin material and having dimensional stability against heat or the like is used for the gap member disposed in the gap of the core. And the gap member shape | molded with the ceramic material etc. is arrange | positioned in the gap provided in the core, and is joined to a core with an adhesive agent etc.

  As described above, in order to place a gap member formed of a ceramic material or the like in a gap provided in a core that is a magnetic body, a step of forming the gap member with a ceramic material or the like, and bonding the gap member to the core The process is complicated because it has a process of joining with an agent or the like. Thereby, the productivity of the reactor for the voltage converter may be reduced, and the manufacturing cost may be increased.

Accordingly, an object of the present invention is to provide a method for manufacturing a reactor for a voltage converter that further improves productivity and further suppresses manufacturing costs.

A method for manufacturing a reactor for a voltage converter according to the present invention includes a core that is a magnetic body provided with a gap having a predetermined width, and a gap member that is disposed in the gap of the core and includes a ceramic material joined to the core. A method for manufacturing a reactor for a voltage converter that manufactures a reactor for a voltage converter having a structure, wherein the ceramic material and a thermosetting resin for bonding the ceramic material are mixed, and then the thermosetting resin is semi-cured A pre-forming step for pre-forming the gap member preform, an assembly step for assembling the core pre-structure by placing the gap member pre-formed body against the core by placing in the gap of the core, and a core pre- by heating the structure, forming step of forming a core structure to cure the semi-cured thermosetting resin The core preliminary structure is set in a bobbin molding die for molding a resin bobbin that insulates the core and the coil, and the core is set at a first temperature for a predetermined time at which the semi-cured thermosetting resin is cured. The bobbin is made thermoplastic by injecting a thermoplastic resin for bobbin molding, which is held in a preliminary structure and then melted and heated at a second temperature higher than the first temperature, into the mold for bobbin molding and then cooled. And a molding step of heating the core preliminary structure with heat generated when molding with resin .

In the method for manufacturing a reactor for a voltage converter according to the present invention, after bobbin molding, the temperature of the thermosetting resin is set in a state where the core preliminary structure is set on the bobbin molding die. Thus, the second temperature is maintained at a third temperature lower than the second temperature for a predetermined time .

As described above , according to the method for manufacturing a reactor for a voltage converter according to the present invention, productivity can be further improved and manufacturing cost can be further suppressed.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a flowchart showing a manufacturing process of a reactor for a voltage converter. The manufacturing process of the voltage converter reactor includes a core preparation process (S10), a preforming process (S12), an assembling process (S14), and a forming process (S16).

  A core preparation process (S10) is a process of preparing the core which is a magnetic body used for the reactor for voltage converters. An electromagnetic steel plate can be used for the core. And it is preferable to use the silicon (Si) steel plate excellent in the high frequency magnetic characteristic for an electromagnetic steel plate. As the core, a block-shaped core that is a core in which electromagnetic steel sheets are laminated may be used.

  For the core, use a powder magnetic core formed by mixing metal magnetic powder such as Fe-Si alloy with a binder and press forming, an amorphous core formed from an amorphous magnetic material, or a ferrite core formed from a ferrite magnetic material. can do. Of course, the core which is a magnetic body is not limited to the above materials.

  A single core may be used as the core, or a core divided into a plurality of cores may be used. As the core, a ring-shaped core, a U-shaped core, or the like can be used. Of course, the shape of the core is not limited to the above shape.

  A gap having a predetermined width is provided in the core. The reason why the gap is provided in the core is that, as described above, by providing the magnetic gap, it is possible to suppress a decrease in inductance in the reactor for the voltage converter. The reason why the width of the gap provided in the core is determined to be a predetermined width is that when the gap width increases, the magnetic flux leaks from the gap and the inductance in the voltage converter reactor may not be substantially constant.

  The predetermined width of the gap provided in the core is, for example, 1 mm to 3 mm. Of course, depending on other conditions, the predetermined width of the gap provided in the core is not limited to the above width. Moreover, the gap provided in a core may be provided in one place of a core, and may be provided in several places of a core. For example, when using the core divided | segmented into several, a gap can be provided in the several places of a core.

  The preforming step (S12) is a step of preliminarily forming the gap member preform by mixing the ceramic material and the thermosetting resin for bonding the ceramic material and then semi-curing the thermosetting resin. .

  The gap member is formed including a ceramic material that is a non-metallic inorganic material. The gap member is formed including a ceramic material because the ceramic material has an insulating property. In addition, as described above, since the thermal expansion coefficient of ceramic materials is generally smaller than that of synthetic resin materials, ceramic materials have better dimensional stability against heat than synthetic resin materials. is there.

The ceramic material is used as a filler for forming the gap member. As the ceramic material, for example, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), aluminum nitride (AlN), boron nitride (BN), or the like can be used. Of course, the ceramic material is not limited to the ceramic material.

  As the ceramic material, it is preferable to use a powdered ceramic material. This is because ceramic powder can be easily mixed with other materials. When ceramic powder is used, the ceramic powder can be used after adjusting to a predetermined particle size. Of course, depending on other conditions, ceramic materials such as short fibers and whiskers can be used as the ceramic material.

  The thermosetting resin is used as a binder for bonding ceramic materials. As the thermosetting resin, an epoxy resin, an unsaturated polyester resin, a phenol resin, or the like can be used. Of course, the thermosetting resin is not limited to the above thermosetting resin. Moreover, a thermosetting resin can be used including a hardening | curing agent, a solvent, etc.

  As will be described later, it is preferable to use a thermosetting resin that is cured by heat generated when a bobbin that insulates the core and the coil is molded from a thermoplastic resin. This is because the thermosetting resin can be cured simultaneously with the bobbin molding. In the case where the bobbin is molded with polyphenylene sulfide resin (PPS) which is a thermoplastic resin, it is preferable to use the epoxy resin or unsaturated polyester resin as the thermosetting resin. This is because the epoxy resin or the unsaturated polyester resin is cured by heat generated when the bobbin is molded with polyphenylene sulfide resin (PPS).

  The ceramic material and the thermosetting resin are mixed at a predetermined mixing ratio. The ceramic material is preferably contained in a volume ratio of 50 vol% or more. This is because, when the content of the thermosetting resin is large, the coefficient of thermal expansion of the gap member to be molded increases, and the dimensional stability against heat or the like decreases. The ceramic material is more preferably contained in a volume ratio of 75 vol% or more. This is because the dimensional stability against heat and the like is further improved by further reducing the thermal expansion coefficient of the gap member to be molded. Moreover, the mixer used for mixing ceramic material and a thermosetting resin can generally use the mixer used for mixing ceramic materials etc.

  A ceramic material and a thermosetting resin are mixed to produce a paste-like mixture, for example, and then molded into a gap member shape. In order to mold the gap member shape, the paste-like mixture can be cast into a gap member shape by pouring into a mold having a predetermined shape, for example. Thereby, the paste-like mixture can be formed into a gap member shape, for example, a plate shape. Further, a clay-like mixture may be prepared by mixing a ceramic material and a thermosetting resin, and may be molded into a plate shape by rolling or the like. Of course, depending on other conditions, the molding in the mixture of the ceramic material and the thermosetting resin is not limited to the above method.

  After the mixture of the ceramic material and the thermosetting resin is molded into a gap member shape, the thermosetting resin contained in the mixture is semi-cured to preform the gap member preform. The semi-curing of the thermosetting resin contained in the mixture of the ceramic material and the thermosetting resin is achieved by providing the gap member preform with a predetermined rigidity and a predetermined adhesiveness. It is for improving the handling property of the. In order to semi-cure the thermosetting resin, the mixture of the ceramic material and the thermosetting resin is held at room temperature for a predetermined time. Of course, depending on other conditions, the thermosetting resin can be semi-cured by heating the mixture of the ceramic material and the thermosetting resin.

  The assembly step (S14) is a step of assembling the core preliminary structure by placing the gap member preform in the gap of the core and abutting the core member. FIG. 2 is a schematic view showing a cross section of the core preliminary structure 10. The gap member preform 12 is disposed in the gap of the core 14 as shown in FIG. The gap member preform 12 and the core 14 are disposed in contact with each other by providing the gap member preform 12 while abutting against the core 14.

  Here, since the thermosetting resin contained in the gap member preform 12 is semi-cured, the gap member preform 12 has predetermined rigidity and predetermined adhesiveness as described above. Yes. Therefore, the core preliminary structure 10 can be easily assembled. In addition, even after the core preliminary structure 10 is assembled, the gap member preform 12 has a predetermined adhesiveness, so that the gap between the gap member preform 12 and the core 14 can be suppressed. it can.

  Returning to FIG. 1 again, in the molding step (S16), by heating the core preliminary structure 10, the semi-cured thermosetting resin contained in the gap member preform 12 is cured to mold the core structure. It is a process to do.

  The core preliminary structure 10 is set in a bobbin molding die for forming a bobbin around which a coil such as a copper wire is wound around the core structure. The bobbin has a function as an insulator for ensuring insulation between the core and the coil. Therefore, the bobbin is molded by, for example, injection molding a synthetic resin material that is an insulating material on the core preliminary structure 10.

  Here, a thermoplastic resin is used as the synthetic resin material for forming the bobbin. For the thermoplastic resin, for example, polyphenylene sulfide resin (PPS), polyamide resin, or the like is used. Of course, the thermoplastic resin is not limited to the above thermoplastic resin. The bobbin is preferably formed including a position where the gap member is disposed. Of course, depending on other conditions, the bobbin is not limited to the above position.

  The bobbin molding die is heated in advance by a heating device such as a heater to a predetermined temperature before injecting the thermoplastic resin. When polyphenylene sulfide resin (PPS) is used as the thermoplastic resin, the bobbin molding mold temperature is heated to 150 ° C. Of course, depending on other conditions, the temperature of the bobbin molding die is not limited to the above temperature.

  Prior to injecting the thermoplastic resin, the core preliminary structure 10 is preferably held in the bobbin molding die at a predetermined bobbin molding die temperature for a predetermined time, for example, 1 minute. By holding the core preliminary structure 10 in the state where it is set in a bobbin molding die at the above temperature, curing of the semi-cured thermosetting resin contained in the gap member preform 12 can be advanced. is there. By proceeding with the curing of the semi-cured thermosetting resin in this way, the gap member pre-molding disposed in the core pre-structure 10 that is likely to occur due to resin pressure when the thermoplastic resin is injected into the bobbin molding die. This is because the displacement and breakage of the body 12 can be suppressed. Of course, depending on other conditions, the thermoplastic resin can be injected immediately after the core preliminary structure 10 is set in the bobbin molding die.

  A thermoplastic resin is injected into a bobbin molding die on which the core preliminary structure 10 is set, and the bobbin is injection-molded into the core preliminary structure 10. The thermoplastic resin is heated in advance to the melting point or higher in order to melt it. When polyphenylene sulfide resin (PPS) is used as the thermoplastic resin, the polyphenylene sulfide resin (PPS) is heated to 320 ° C. by a heating device such as a heater.

  The molten thermoplastic resin is injected into the bobbin molding die for a predetermined injection time and a predetermined pressure holding time. When the thermoplastic resin is a polyphenylene sulfide resin (PPS), for example, the molten polyphenylene sulfide resin (PPS) is injected into a bobbin molding die with an injection time of 2 seconds and a pressure holding time of 8 seconds. Then, the melted polyphenylene sulfide resin (PPS) is cooled and cured for 30 seconds, for example. Thereby, the bobbin shape | molded with polyphenylene sulfide resin (PPS) is formed.

  The heat generated when the molten thermoplastic resin cools and cures is transferred directly to the gap member preform 12 or indirectly through the core 14. Then, the molten thermoplastic resin is heated by the heat generated when it is cooled, and the curing of the semi-cured thermosetting resin, for example, epoxy resin, included in the gap member preform 12 proceeds.

  The core preliminary structure 10 may be continuously held by a bobbin molding die after injection molding of a thermoplastic resin to mold a bobbin. Then, the bobbin molding die is held at a temperature for curing the thermosetting resin, for example, 150 ° C. in the case of an epoxy resin or an unsaturated polyester resin for a predetermined time to further cure the thermosetting resin. It can be post-cured. The heat of the bobbin molding die is transferred directly to the gap member preform 12 or indirectly through the core 14. Then, by heating with the heat transmitted to the gap member preform 12, the thermosetting resin can be further cured and post-cured.

  As described above, the semi-cured thermosetting resin contained in the gap member preform 12 is cured to mold the core structure. FIG. 3 is a schematic diagram showing a cross section of the core structure 16 in which a bobbin is formed. As shown in FIG. 3, the gap member 18 is formed by curing the semi-cured thermosetting resin, and the formed gap member 18 and the core 14 are joined by the thermosetting resin, so that the core structure 16 is formed. Molded. Further, a bobbin 20 is formed in the core structure 16 at a position including the gap member 18.

  Here, the core preliminary structure 10 may be heated in a resin curing furnace or the like before the bobbin 20 is formed. Thereby, the core structure 16 can be molded by curing the semi-cured thermosetting resin contained in the gap member preform 12. As the resin curing furnace or the like, a heating furnace or the like generally used for curing a synthetic resin material can be used. Then, after the core structure 16 is molded, the bobbin 20 can be formed by injection molding a thermoplastic resin on the core structure 16 by the method described above.

  A coil is wound around the core structure 16 in which the bobbin 20 is formed. It is preferable to use a copper wire having a small electric resistance for the coil. Of course, depending on other conditions, the coil is not limited to a copper wire, and other conductors can be used. FIG. 4 is a diagram showing the manufactured voltage converter reactor 22, FIG. 4A is a perspective view of the manufactured voltage converter reactor 22, and FIG. 4B is the manufactured voltage. It is AA sectional drawing of the reactor 22 for converters. As shown in FIG. 4, the coil 24 is wound around a bobbin 20 formed of a thermoplastic resin, which is an insulating material, in order to ensure insulation with the core 14.

  According to the said structure, since the shaping | molding of the gap member by a gap member preform and the joining of a gap member and a core can be performed simultaneously, material cost, an assembly man-hour, etc. can be reduced. Thereby, productivity of the reactor for voltage converters can be improved more and manufacturing cost can further be suppressed.

  According to the above configuration, the bobbin can be simultaneously molded by curing the semi-cured thermosetting resin contained in the gap member preform using heat at the time of bobbin molding. The productivity of the converter reactor can be further improved, and the manufacturing cost can be further suppressed.

  Hereinafter, another embodiment according to the present invention will be described in detail with reference to the drawings. FIG. 5 is a flowchart illustrating a manufacturing process of the voltage converter reactor. The voltage converter reactor manufacturing process includes a core preparation process (S10), a preforming process (S20), and a molding process (S22). In addition, the same code | symbol is attached | subjected to the same element and detailed description is abbreviate | omitted.

  A core preparation process (S10) is a process of preparing the core which is a magnetic body used for the reactor for voltage converters as mentioned above. It is preferable to use an electromagnetic steel plate, for example, a silicon (Si) steel plate excellent in high-frequency magnetic properties for the core that is a magnetic body. As the core, a block-shaped core that is a core in which electromagnetic steel sheets are laminated can be used. The core is provided with a gap having a predetermined width, for example, 1 mm to 3 mm.

  The pre-forming step (S20) is a step of pre-forming the core preliminary structure by mixing the ceramic material and the thermosetting resin for bonding the ceramic material and then filling the gap in the core.

The ceramic material is used as a filler for forming the gap member. As described above, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), or the like, which is an insulating material, is used for the ceramic material. Further, the thermosetting resin is used as a binder for bonding ceramic materials. As described above, an epoxy resin or the like is used for the thermosetting resin.

  As described above, the ceramic material and the thermosetting resin are mixed at a predetermined mixing ratio to produce, for example, a paste-like mixture. Then, the core mixture is pre-molded by filling the paste-like mixture into the core gap. FIG. 6 is a view showing the core preform 30. The filling method of the paste-like mixture 32 can be performed by applying the paste-like mixture 32 to the surface of the core 14 with a brush or a spatula. Alternatively, a ceramic material and a thermosetting resin may be mixed to prepare a clay-like mixture, and the gap between the cores 14 may be filled with the clay-like mixture by press-fitting or the like.

  Here, the thermosetting resin contained in the mixture of the ceramic material and the thermosetting resin is preferably used without being semi-cured. This is because the gap between the cores can be easily filled with the mixture of the ceramic material and the thermosetting resin. Of course, depending on other conditions, the thermosetting resin contained in the mixture of the ceramic material and the thermosetting resin may be semi-cured.

  The forming step (S22) is a step of forming the core structure by curing the thermosetting resin by heating the core preliminary structure 30. As described above, the core preliminary structure 30 is preferably heated by heat during bobbin molding. In addition, the core preliminary structure 30 may be heated using a resin curing furnace or the like. And after a bobbin is shape | molded, a coil is wound around a bobbin and the reactor for voltage converters is completed.

  According to the above configuration, since the gap member can be formed by filling the gap of the core with the mixture of the ceramic material and the thermosetting resin and the gap member and the core can be joined at the same time, the material cost and assembly are reduced. Man-hours and the like can be reduced. Thereby, productivity of the reactor for voltage converters can be improved more and manufacturing cost can further be suppressed.

  According to the above configuration, by using the heat at the time of bobbin molding, the thermosetting resin contained in the mixture of the ceramic material and the thermosetting resin filled in the gap of the core is further cured. Since the molding can be performed at the same time, the productivity of the reactor for the voltage converter can be further improved and the manufacturing cost can be further suppressed.

  In the above configuration, the reactor for the voltage converter was manufactured by the core preparation step (S10), the preliminary molding step (S12), the assembly step (S14), and the molding step (S16).

  In the core preparation step (S10), a block-like core in which silicon (Si) steel plates are laminated is used as the core used in the reactor for the voltage converter.

  In the pre-forming step (S12), after mixing the ceramic material and the thermosetting resin for bonding the ceramic material, the thermosetting resin was semi-cured to pre-form the gap member pre-formed body. Alumina powder was used as the ceramic material. An epoxy resin was used as the thermosetting resin. And 77 vol% alumina powder and 23 vol% epoxy resin were mixed with the mixer. When the mixing ratio of the alumina powder and the epoxy resin is expressed by a mass ratio, the alumina powder is 90% by mass and the epoxy resin is 10% by mass.

  Then, the alumina powder and the epoxy resin were mixed to prepare a paste-like mixture, which was molded into a plate shape using a mold or the like. Thereafter, the epoxy resin contained in the paste-like mixture was semi-cured at room temperature, and a gap plate preform as a gap member preform was preformed.

  In the assembly step (S14), the core preliminary structure was assembled by placing the gap plate preform in the gap of the core by overlapping the core and the gap plate preform.

  In the molding step (S16), first, a core preliminary structure composed of a core and a gap plate preform was set in a bobbin molding die. The bobbin molding mold was set so that the mold temperature was 150 ° C. Then, after setting the core preliminary structure in the bobbin molding die, it is held for about one minute before injecting the polyphenylene sulfide resin (PPS) to cure the semi-cured epoxy resin contained in the gap plate preform. Proceeded.

  The core preliminary structure was set in a bobbin molding die and held for 1 minute, and then a polyphenylene sulfide resin (PPS) heated to 320 ° C. and melted was injected to inject the bobbin. The injection molding conditions are an injection time of 2 seconds and a pressure holding time of 8 seconds. Thereafter, the polyphenylene sulfide resin (PPS) was cooled and cured for a cooling time of 30 seconds.

  Then, after the polyphenylene sulfide resin (PPS) was cured, the core preliminary structure was further heated at 150 ° C. for 2 hours with a bobbin molding die to post-cure the epoxy resin contained in the gap plate preform. .

  As described above, the semi-cured epoxy resin contained in the gap plate preform was cured to form the gap plate, and the gap plate and the core were bonded to form the core structure. And the copper wire which is a coil was wound around the bobbin formed in the core structure, and the reactor for voltage converters was completed. As a result of evaluating the vibration and the like for the manufactured voltage converter reactor, it was found that there was no problem due to vibration and the like.

In embodiment of this invention, it is a flowchart which shows the manufacturing process of the reactor for voltage converters. In the embodiment of the present invention, it is a schematic diagram showing a cross section of the core preliminary structure 10. In embodiment of this invention, it is a schematic diagram which shows the cross section of the core structure 16 in which the bobbin was formed. In embodiment of this invention, it is the figure which shows the reactor 22 for voltage converters manufactured. In other embodiment of this invention, it is a flowchart which shows the manufacturing process of the reactor for voltage converters. In other embodiment of this invention, it is a figure which shows the core preform 30. FIG.

Explanation of symbols

  10, 30 Core preliminary structure, 12 Gap member preform, 14 Core, 16 Core structure, 18 Gap member, 20 Bobbin, 22 Reactor for voltage converter, 24 coils, 32 Pasty mixture.

Claims (2)

A core that is a magnetic body provided with a gap of a predetermined width;
A gap member including a ceramic material disposed in the core gap and bonded to the core;
A voltage converter reactor manufacturing method for manufacturing a voltage converter reactor including a core structure having
A pre-molding step in which the ceramic material and the thermosetting resin for bonding the ceramic material are mixed, and then the thermosetting resin is semi-cured to preform the gap member preform,
An assembly step of assembling the core preliminary structure by placing it in the gap of the core and abutting against the core to provide a gap member preform.
Bobbin molding for molding a resin bobbin that insulates the core from the coil, in which a core structure is formed by curing the semi-cured thermosetting resin by heating the core preliminary structure. The core preliminary structure is set in the mold, the core preliminary structure is held for a predetermined time at a first temperature for curing the semi-cured thermosetting resin, and then melted at a second temperature higher than the first temperature. A molding step of heating the core preliminary structure with heat generated when the bobbin is molded with the thermoplastic resin by injecting the heated thermoplastic resin for bobbin molding into the bobbin molding die and then cooling ,
The manufacturing method of the reactor for voltage converters characterized by having. In the manufacturing method of the reactor for voltage converters of Claim 1,
After bobbin molding, the bobbin molding die is set to a third temperature lower than the second temperature, which is a temperature for curing the thermosetting resin in a state where the core preliminary structure is set on the bobbin molding die. The manufacturing method of the reactor for voltage converters characterized by hold | maintaining continuously .

Images