JP4888324B2 - Reactor manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a reactor mounted on an electric vehicle, a hybrid vehicle, or the like.

  A reactor of a power conversion circuit is generally housed in a housing (case) in a posture in which a coil is formed at two longitudinal portions of a reactor ring that is substantially horizontally long in plan view. This reactor core is composed of multiple cores of magnetic steel sheets or split cores consisting of dust cores. A gap plate made of nonmagnetic material is interposed between each split core, and the gap plate and core are bonded. Reactors are formed by adhesive bonding with an agent.

  A heat radiating plate (heat sink) is provided on the lower surface (bottom surface) of the housing, and a cooler that circulates cooling water and air is provided below the heat sink, and generates heat when current is applied to the coil. In general, a structure is used in which a coil or a reactor core is allowed to escape to the outside through the heat sink and cooling via a cooler. Here, a sealing resin body is molded between the housing and the reactor core accommodated in the housing, and the heat from the coil or the reactor core is transferred to the heat sink via the sealing resin body. Heat is transferred. There is also a so-called float reactor in which a gap is formed between the coil provided in the reactor and the heat dissipation plate, and the sealing resin body is interposed in the gap. An example is disclosed.

  In addition to the float structure reactor described above, in the reactor in which the coil provided in the reactor is in contact with the bottom surface of the housing, a sealing resin body having heat radiation performance is interposed between the coil or the reactor and the housing. This is inevitable in securing the heat dissipation performance of the reactor. In particular, the housing is generally molded from aluminum or an aluminum alloy, but the adhesive strength between the aluminum housing and the sealing resin body is sufficient, and generally due to heat cycles and repeated vibrations driven by the reactor. There is little possibility of delamination between the two.

  However, the adhesive strength between the reactor core and the sealing resin body is relatively small, and the conventional reactor has a problem that peeling between the reactor core and the sealing resin body is likely to occur during a process such as a heat cycle. It was. When separation occurs between the reactor core and the sealing resin body, an air gap is interposed at the separation portion, and the heat dissipation performance from the reactor core to the housing is significantly reduced. Therefore, how to increase the adhesive strength between the reactor core and the housing was one of the important issues in the field.

  In particular, reactors mounted on electric vehicles, hybrid vehicles, etc. generally have large vibrations and large amounts of heat because large currents and voltages are applied, so it is important to ensure the bonding posture between the reactor components described above. The nature is even higher.

  However, in the conventional reactor including the reactor disclosed in Patent Document 1, the adhesive strength between the reactor core and the sealing resin body is not necessarily high, and still solves the problem of suppressing the above-described peeling. Not reached.

JP 2006-351675 A

  The present invention has been made in view of the above-described problems, and provides a method for manufacturing a reactor in which separation between a reactor core and a housing is less likely to occur with respect to repetitive vibrations and heat cycles accompanying the driving of the reactor. For the purpose.

  In order to achieve the above object, a method of manufacturing a reactor according to the present invention includes a housing, a reactor core that is accommodated and fixed in the housing in a posture equipped with a coil, and a sealing resin that is formed by filling and curing a silicone resin in the housing. A first step of housing and fixing a reactor core having a coil in the housing, and then a second step of impregnating and hardening a silicone resin in the housing. In the method for manufacturing a reactor including at least, the reactor is preheated at least in advance of the first step.

Here, the reactor core is formed by joining two U-shaped cores having magnetism, or in addition to this, an I-type core with an adhesive via a gap plate. The U-type core and I-type core may be formed from a laminate formed by laminating silicon steel plates, and a magnetic powder in which a soft magnetic metal powder or a soft magnetic metal oxide powder is coated with a resin binder is press-formed. You may form from the powder magnetic core formed. As the soft magnetic metal powder, iron, iron-silicon alloy, iron-nitrogen alloy, iron-nickel alloy, iron-carbon alloy, iron-boron alloy, iron-cobalt alloy, iron- Phosphorus alloys, iron-nickel-cobalt alloys, iron-aluminum-silicon alloys, and the like can be used. The gap plate can be formed of ceramics such as alumina (Al ₂ O ₃ ) or zirconia (ZrO ₂ ).

  Further, the housing can be formed from aluminum or an alloy thereof, and a heat dissipating base formed separately or integrally with the housing may be provided below (lower surface). . There is also a form in which a cooler in which cooling water or cooling air from a radiator or the like is circulated further below the heat radiating base.

  The reactor manufactured by the manufacturing method of the present invention may be a reactor having the float structure described above, or may be a reactor in which the coil and the bottom plate of the housing are in contact with each other. In this manufacturing method, for example, two U-shaped cores and a gap plate are formed, a reactor core is manufactured while forming a coil on the outer periphery of the core, and this is accommodated and fixed in the housing (first step). . Here, in the case of a reactor having a float structure, the reactor core is accommodated and fixed in the housing in a posture in which the reactor core slightly floats from the bottom plate of the housing. For example, a step portion is provided in the bottom plate of the housing, a groove is provided in the bottom plate portion where the coil is installed, or a fixing means such as a leaf spring is provided in the housing, thereby positioning the reactor core. There is a holding method.

  Next, as a second step, the reactor is manufactured by filling the housing with a silicone resin and curing it. The silicone resin may be mixed with an appropriate amount of filler made of silica, alumina, boron nitride, or the like.

  In the manufacturing method of the present invention, prior to the first step, for example, the reactor core and the housing are preheated to a predetermined temperature, thereby increasing the adhesive strength between the reactor core and the sealing resin body.

  According to experiments by the present inventors, it has been found that preheating the reactor core and the housing increases the adhesive strength as compared with the conventional manufacturing method without preheating.

  Furthermore, according to experiments by the present inventors, it has been demonstrated that the adhesive strength between the reactor core and the sealing resin body can be further increased by preheating only the reactor core in advance.

  With regard to an increase in adhesive strength between a sealing resin body made of silicone resin and a reactor core made of, for example, a dust core, at least the reactor core is preheated and then housed in the housing, and the sealing resin is filled in the housing As one of the reasons why the adhesive strength between the reactor core and the sealing resin body increases, the wettability of the reactor core surface is improved by preheating, especially in the case of silicone resin, the anchor effect is exhibited, It is thought that the adhesive strength between the two increases.

  In addition, regarding the preheating temperature condition described above, it has been demonstrated that a high increase in adhesive strength can be obtained at least when the reactor core is preheated in the range of 70 to 120 ° C.

  Here, if the reactor core is preheated to a temperature higher than 120 ° C., the curing temperature of the silicone resin is about 120 ° C., which is not preferable because only the bonded portions of both are rapidly cured.

  According to the method for manufacturing a reactor of the present invention, the adhesive strength (or peel strength) between the sealing resin body and the reactor core is conventionally increased by a simple method in which at least the reactor core is preheated to a predetermined temperature range in advance. As compared with the reactor, it is possible to greatly increase, and it is possible to obtain a high-quality reactor excellent in durability and heat dissipation without increasing the manufacturing cost.

  Since the reactor manufactured by the manufacturing method of the present invention is a reactor having excellent heat dissipation performance and high durability as described above, it is a recent hybrid that has a problem of having a high-performance and durable mounting device. Ideal for applications in cars and electric vehicles.

  As can be understood from the above description, according to the reactor manufacturing method of the present invention, the adhesive strength between the reactor core and the housing can be remarkably increased, and thus a reactor having excellent heat dissipation performance over a long period of time can be obtained. Obtainable. In addition, this manufacturing method is simple enough to preheat at least the reactor core prior to assembly or the like, and does not raise the manufacturing cost at all.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of an embodiment of a reactor manufactured by the manufacturing method of the present invention, and FIG. 2 is an enlarged view of a portion II in FIG. FIG. 3 shows a test piece formed by changing a preheating portion and a preheating temperature with respect to a test piece made up of a reactor core, a sealing resin body, and a housing bottom plate. FIG. Fig. 3b shows a comparative example without preheating, Fig. 3c shows a comparative example in which the reactor core is preheated in the range of 40 to 65 ° C, and Fig. 3d Shows a comparative example in which the reactor core and the housing are preheated in the range of 80 to 120 ° C. FIG. 4 is a diagram illustrating a situation in which a tensile test is performed on the test piece illustrated in FIG. 3, and FIG. 5 is a diagram illustrating an experimental result regarding the adhesive strength for each of the example and the comparative example of FIG. Although the illustrated embodiment of the reactor is a reactor having a float structure, it goes without saying that the reactor formed by the manufacturing method of the present invention includes a reactor in which the coil and the housing bottom plate are in contact with each other. Further, the reactor core includes a steel plate laminate in which electromagnetic steel plates are laminated in addition to the dust core shown in the drawing.

  FIG. 1 is a longitudinal sectional view of an embodiment of a reactor manufactured by the manufacturing method of the present invention, and FIG. 2 is an enlarged view of a portion II thereof. The reactor 10 includes a cooler 7 that recirculates cooling water from a radiator or the like, a heat dissipating base 6 fixed to the cooler 7, and an aluminum housing 1 that is bonded and fixed on the upper surface of the heat dissipating base 6. And a reactor core 2 accommodated and fixed in the housing 1 via a fixing member 5 and formed with a coil 3, and a sealing resin body 4 formed by filling and curing the silicone resin in the housing 1. Has been. In the illustrated example, a stepped portion is provided on the side wall 11 of the housing 1 and a fixing member 5 is provided on the stepped portion. However, a structure in which the end of the reactor core 2 is directly placed on the stepped portion. It may be.

  The reactor core is formed in an annular shape as a whole by adhering the ends of two U-shaped cores having a U-shape in plan view with an adhesive via a gap plate. This U-shaped core is formed from a powder magnetic core formed by pressure-molding magnetic powder, and the gap plate is formed from ceramics.

  The sealing resin body 4 is formed by filling the housing 1 with a mixed material obtained by mixing an appropriate amount of a filler such as silica or alumina into a silicone resin and curing it.

  When the reactor is driven, heat is generated in the coil 3 and the reactor core 2, and this heat is passed through the sealing resin body 4 below the reactor core 2 and the coil 3, for example, as indicated by an arrow in the figure, and further below the housing. 1 is radiated to the cooler 7 through the bottom plate 12 and the heat dissipating base 6.

  Next, the manufacturing method of the reactor 10 shown in FIG. 1 will be outlined.

  First, a U-shaped core and a gap plate are individually manufactured, and a reactor core 2 having an annular shape as a whole is manufactured while a coil bobbin formed around a coil 3 is installed on the outer periphery of the reactor core. The reactor core 2 is preheated to a predetermined temperature, and the end portion of the preheated reactor core 2 is accommodated and fixed in the housing 1 via a fixing member 5 in the housing 1. At this stage, a float structure in which a gap is formed between the coil 3 and the bottom plate 12 of the housing 1 is formed. Not only the reactor core 2 but also the housing 1 may be preheated under the same temperature conditions.

  Next, the housing 1 is filled with a mixed material in which an appropriate amount of filler is mixed with silicone resin, and the reactor 10 is manufactured after the curing.

  Regarding the above-mentioned residual heat, it is most preferable to preheat only the reactor core 2 at a temperature in the range of 70 to 120 ° C. However, a method of preheating both the reactor core 2 and the housing 1 at a temperature in the same range may be used. .

  By performing this preheating process before the assembly process of the reactor core 2 and the housing 1, the adhesive strength (or peel strength) at the interface between the reactor core 2 and the sealing resin body 4 shown in the enlarged view of FIG. If only the reactor core 2 is preheated, the effect becomes even higher.

[Experiment to verify the effect on adhesive strength when changing preheating part and preheating temperature and results]
The inventors have made a test piece consisting of a part of each of the reactor core, the sealing resin body, and the housing bottom plate shown in the enlarged view of FIG. 2, and preheating a part of the test piece and changing the preheating temperature. Test pieces were prepared, and the adhesive strength between the reactor core and the sealing resin body in each test piece was measured based on a tensile test.

  FIG. 3 shows the prototyped test pieces. In each case, T1 represents the reactor part of the test piece T, T2 represents the sealing resin body portion of the test piece T made of silicone resin, and T3 represents the test piece. Each of the aluminum housing bottom plates of T is shown. Here, FIG. 3a is a test piece that is obtained by preheating only the reactor core portion T1 at a predetermined temperature of 70 to 120 ° C., and each reactor core of the four case test pieces of Examples 1 to 4 is 70 ° C. Preheated at 80 ° C, 100 ° C and 120 ° C.

  FIG. 3 b shows a test piece according to the conventional manufacturing method, which is manufactured without preheating, and this is referred to as Comparative Example 1. In the case of no preheating, each member shows a normal temperature of 23 ° C. at the time of manufacture.

  Fig. 3c shows the test piece preheated only for the reactor core. This preheated temperature is preheated at a temperature lower than 70 ° C, and the test pieces at preheating temperatures of 40 ° C, 50 ° C and 65 ° C are compared. Example 2, 3 and 4. In addition, although these test pieces are positioned as comparative examples here, they are also included in the scope of the manufacturing method of the present invention in which the members are preheated, and compared with Comparative Example 1 by the conventional method without preheating. In comparison, it can be positioned as an example. In determining the optimum preheating range, the comparison with Examples 1 to 4 is only a comparative example.

  FIG. 3d is a test piece in which the reactor core and the bottom plate of the housing are preheated. These preheat temperatures are preheated at a predetermined temperature in the range of 80 to 120 ° C., and each residual heat at 80 ° C., 100 ° C., and 120 ° C. The temperature test pieces are referred to as Comparative Examples 5, 6, and 7, respectively. The comparative examples 5 to 7 are also included in the scope of the manufacturing method of the present invention in which the members are preheated. In comparison with the examples 1 to 4 in which only the reactor core is preheated in the optimum temperature range. Here, it is only a comparative example, and in comparison with comparative example 1, it can be positioned as an example.

  Three test pieces are prepared for each case described above, and subjected to a tensile test to apply a tensile force from above and below as shown in FIG. 4, and from the test result in this tensile test, adhesion between the reactor core and the sealing resin body is performed. The strength was determined. Note that the tensile strength between the sealing resin body and the bottom plate of the housing is sufficiently larger than that of the reactor core and the sealing resin body. Has occurred. The results of the test are shown in Table 1 below and FIG.

  From the results shown in Table 1 and FIG. 5, only the reactor cores of Examples 1 to 4 were preheated in the range of 70 to 120 ° C., although there were errors due to the flatness of the housing bottom plate surface for each test piece in each case. In this case, it was proved that a high adhesive strength of 0.8 MPa or more can be obtained.

  When the comparative example 1 made by the conventional manufacturing method and the comparative examples 2 to 7 made by the manufacturing method of the present invention are compared, the adhesive strength is increased as compared with the comparative example 1, and the comparative example 2 It can be seen that a sufficient effect is obtained for ˜7.

  Furthermore, when compared in Comparative Examples 2 to 7, preheating the reactor core and the housing at an optimum temperature range of 80 to 120 ° C. is more than when preheating only the reactor core at a temperature range lower than the optimum range. It has been demonstrated that the adhesive strength is high.

  Moreover, it is demonstrated by comparing Examples 2-4 and Comparative Examples 5-7 that the adhesive strength is higher when only the reactor core is preheated.

    From the results of this experiment, it was demonstrated that the adhesive strength between the reactor core and the sealing resin body becomes the highest when only the reactor core is preheated in the range of 70 to 120 ° C.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

It is a longitudinal section of one embodiment of a reactor manufactured by the manufacturing method of the present invention. It is an enlarged view of the II section of FIG. A test piece comprising a reactor core, a sealing resin body, and a housing bottom plate, showing a test piece made by changing a preheating portion and a preheating temperature, wherein (a) shows only a reactor core at 70 to 120 ° C. (B) shows a comparative example without preheating, (c) shows a comparative example in which the reactor is preheated in the range of 40 to 65 ° C., and (d) ) Shows a comparative example in which the reactor core and the housing are preheated in the range of 80 to 120 ° C. It is the figure explaining the condition which is implementing the tension test to the test piece shown in FIG. It is the figure which showed the experimental result regarding the adhesive strength for every Example and comparative example of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Housing, 11 ... Side wall, 12 ... Bottom plate, 2 ... Reactor core, 3 ... Coil, 4 ... Sealing resin body, 5 ... Fixing member, 6 ... Radiation base, 7 ... Cooler, 10 ... Reactor, T ... Test piece, T1 ... Reactor part of the test piece, T2 ... Sealing resin body part of the test piece, T3 ... Housing bottom plate part of the test piece

Claims (2)

A reactor manufacturing method comprising at least a housing, a reactor core accommodated and fixed in the housing in a posture including a coil, and a sealing resin body formed by filling and curing a silicone resin in the housing. In a method of manufacturing a reactor, comprising at least a first step of accommodating and fixing a reactor core having a coil therein, and then a second step of impregnating and curing a silicone resin in the housing,
Prior to the first step, aft preheated only in the range of 70 to 120 ° C. The reactor core, the increase in the adhesion strength between the reactor core and the resin portion is achieved by the fact A method for manufacturing a reactor. The method of manufacturing a reactor according to claim 1 , wherein the reactor is a vehicle-mounted reactor mounted on a hybrid vehicle or an electric vehicle.

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