JP4775254B2 - Reactor and reactor - Google Patents

Description

  The present invention relates to a reactor core and a reactor, and more particularly, to a reactor core in which a core material forming a reactor core and a gap plate hardly peel off and a reactor including the reactor core.

  When the reactor core is formed of a plurality of core materials, a resin gap plate serving as a spacer is interposed between adjacent core materials, and the gap plate and the core material are bonded and fixed with an adhesive. It is common. Further, as a structure other than interposing a gap plate, there are a form in which ceramic particles disclosed in Patent Document 1 are interposed, a form in which a ceramic sheet having a hollow portion disclosed in Patent Document 2 is interposed, and the like.

  By the way, when the reactor including the reactor is mounted in an engine room of a hybrid vehicle or the like, in such an application, under a cold cycle environment within a range of about −40 ° C. to 150 ° C. due to a change in the use environment. Therefore, in the reactor core in which the gap plate is interposed, there is a problem that peeling is likely to occur at the bonding portion between the core material and the gap plate. This is because the facing surfaces of the conventional core material and the gap plate are both formed flat, and the thickness of the adhesive between them is inevitably the same in any part. It is easy to be affected by the cycle, and the difference in thermal expansion between core material, gap plate, and adhesive increases as the outer peripheral part increases, and the adhesive layer easily peels off due to repeated thermal stress. Is a major factor. In addition, the shear stress which arises in this adhesive bond layer becomes large, so that the thickness of an adhesive bond layer is small.

  Therefore, by increasing the thickness of the adhesive layer, it is possible to increase the durability against the thermal cycle. On the other hand, the thickness of the adhesive layer having low rigidity is increased to increase the static strength of the reactor core itself ( (Rigidity) will be reduced.

JP 2004-247478 A JP 2001-30219 A

  The present invention has been made in view of the above-described problems, and is a reactor core in which a gap plate is interposed between adjacent core members, and the core member and the gap plate are bonded and fixed with an adhesive. It is an object of the present invention to provide a reactor core and a reactor including the reactor core which can increase the durability against the thermal cycle without reducing the static strength of the reactor itself.

  In order to achieve the above object, a reactor core according to the present invention is formed of a plurality of magnetic core materials and a non-magnetic gap plate interposed between adjacent core materials. Reactor core in which the opposing surface of the surface and the gap plate is fixed via an adhesive layer, and at least one of the opposing surfaces of both the core material and the gap plate protrudes most at the center or substantially the center of the opposing surface The adhesive layer is formed so that the thickness of the adhesive layer increases from the center or substantially the center of the bonding surface toward the end thereof.

In the core material, two U-shaped cores are arranged opposite to each other with a space therebetween, and a plurality of rectangular cores (or I-shaped cores) are disposed therebetween, and between the U-shaped cores and the rectangular cores, and between the rectangular cores. A gap plate formed of ceramic such as alumina (Al ₂ O ₃ ) or zirconia (ZrO ₂ ) is interposed between the core material and the gap plate with an epoxy resin adhesive having high heat resistance. Reactor is formed by being fixed.

  The core material is formed from a powder magnetic core formed by pressing soft magnetic powder or a laminated steel plate formed by laminating silicon steel plates. In the present invention, the core material is formed from a powder magnetic core particularly from the viewpoint of formability. preferable. Examples of soft magnetic powders include iron, iron-silicon alloys, iron-nitrogen alloys, iron-nickel alloys, iron-carbon alloys, iron-boron alloys, iron-cobalt alloys, iron-phosphorous alloys. An alloy, an iron-nickel-cobalt alloy and an iron-aluminum-silicon alloy can be used, and an insulating coating made of a silicon resin or the like is formed on the surface of the alloy to produce soft magnetic powder.

  In the reactor core of the present invention, at least one of the facing surfaces of both the core material and the gap plate is formed in a protruding shape with the center or substantially center of the facing surface protruding most. That is, there are a form in which only the facing surface of the core material is formed into a projecting shape, a form in which only the facing surface of the gap plate is formed into a projecting shape, and a form in which both facing surfaces are formed into a projecting shape.

  Since at least one of the core material and the gap plate has such a configuration, the thickness of the adhesive layer is inevitably the smallest (thinner) at the center of the opposing surface or in the vicinity thereof, and is directed toward the end of the opposing surface. It becomes larger (thicker) and exhibits the thickest layer shape at the end.

  As described above, the thickness of the adhesive layer on the facing surface of the core material (or gap plate) is thicker at the end than the center, thereby reducing the generated shear stress due to thermal expansion due to the thermal cycle. Can do. As a result, it is possible to make it difficult for the adhesive layer and the core material or the gap plate to be peeled off, leading to an improvement in the durability (cooling durability) of the reactor core.

  On the other hand, the thickness of the adhesive layer is relatively thin at the central portion of the opposing surface, which causes the adhesive layer to become too thick, reducing the strength (static strength) of the reactor core itself. Can be resolved at the same time.

  Here, as an embodiment of the protruding shape in which the center or substantially center of the opposing surface protrudes most, the protruding shape is a curved shape, the protruding shape is a truncated cone, and the protruding shape is a truncated shape Examples include a pyramid shape, and a protruding shape having a cone shape or a pyramid shape.

  Depending on the conditions under which the reactor core (or reactor) is placed, the generated shear stress may vary depending on the site even at the end of one adhesive layer. For example, the shear stress tends to increase at a site on the engine side where the temperature difference tends to increase. Therefore, even in an embodiment in which the generated shear stress due to the temperature difference is obtained in advance according to the environment to be used, and the thickness is changed for each end portion of the adhesive layer according to the stress value. Good. Furthermore, you may shape | mold the core material or gap board from which the site | part which protrudes most in a protrusion shape becomes the position which deviated to one direction from the center of the opposing surface.

  Furthermore, the reactor by this invention comprises the said reactor core, It is characterized by the above-mentioned.

  Adhesive layer that adheres and fixes the core material and the gap plate without substantially reducing the static strength of the reactor core by using the reactor core described above and forming a reactor with a coil formed on the outer periphery of the core. Since the peel strength with respect to the thermal cycle can be increased, the durability of the reactor is enhanced. Therefore, this reactor is particularly suitable for a hybrid vehicle that is required to have durability against cooling.

  As can be understood from the above description, according to the reactor core of the present invention, the reactor core itself has a very simple structure in which the thickness of the adhesive layer for bonding and fixing the core material and the gap plate is changed for each part. The durability of the adhesive layer against a cold cycle can be enhanced without reducing the static strength.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a reactor core according to the present invention, and FIG. 2 is a perspective view of a reactor including the reactor core shown in FIG. 3, 4 and 5 are perspective views of the embodiment of the core material. 6 and 7 are longitudinal sectional views of the embodiment of the reactor core. 8 and 9 are schematic views showing an embodiment of a method for manufacturing a reactor core. 10a is a perspective view of a part of the test piece of the reactor core of the present invention used in the shear test, FIG. 10b is a view taken along the line bb of FIG. 10a, and FIG. 10c is a part of the conventional reactor core. This is a test piece. FIG. 11 is a graph illustrating the conditions for one cycle of the thermal cycle test, FIG. 12 is a schematic diagram illustrating an outline of the shear fracture test, and FIG. 13 is a graph illustrating the shear fracture test result. FIG. 14 is a perspective view of an FEM analysis model used for shear stress analysis (static analysis) when the thickness of the adhesive layer is changed, and FIGS. 15 and 16 are graphs showing the results of shear stress analysis.

  FIG. 1 shows a reactor core 10 according to the present invention. The reactor core 10 is a U-shaped core 1 or 1 having a U shape in plan view, and a core having a rectangular shape in plan view disposed with a space therebetween. (Hereinafter referred to as I-type core 2), gap plate 3 interposed between U-type core 1 and I-type core 2 and between I-type cores 2 and 2, gap plate 3 and cores 1 and 2 And the adhesive layer 4 that adheres to each other, and as a whole, the plan view is formed in a horizontally long annular shape. A magnetic circuit is formed in the annular direction.

Both the U-type core 1 and the I-type core 2 are formed of a powder magnetic core formed by press-molding soft magnetic powder or a laminated steel plate formed by laminating silicon steel plates. The gap plate 3 is formed of a nonmagnetic material ceramic such as alumina (Al ₂ O ₃ ). Furthermore, the adhesive layer 4 is formed of an epoxy resin adhesive or the like.

  Reactors 30 are formed by forming coils 20 and 20 formed by winding conductive wires in a straight section in the longitudinal direction of the reactor core 10 (see FIG. 2). This reactor comprises the power converter device mounted in vehicles, such as a hybrid vehicle, for example.

  FIG. 3 is an enlarged perspective view of the I-type core 2. The I-type core 2 is formed into a smooth curved shape as a whole, with the shape of the side surface (opposing surface 21) facing the gap plate 3 protruding most at the center or near the center. In addition, although illustration is abbreviate | omitted, the opposing surface which opposes a gap board in the edge part of the U-shaped core 1 is also shape | molded by the curved shape which the center protruded similarly to FIG.

  FIG. 3 is a longitudinal sectional view of the longitudinal portion of the reactor core 10 in which both opposing surfaces 21 and 21 of the I-type core 2 are formed in the shape shown in FIG. 3, and the opposing surface of the U-type core 1 is also formed in the same shape as FIG. This is shown in FIG.

  In the embodiment shown in FIG. 6, the opposing surface of the gap plate 3 is flat, and the adhesive layer 4 has a thickness at the end by forming the opposing surfaces of the cores 1 and 2 into the shape described above. The layer shape becomes thicker and gradually becomes thinner toward the center.

  By forming such a layer-shaped adhesive layer, the thickness of the adhesive layer is reduced at the center while reducing the generated shear stress due to thermal expansion due to the thermal cycle at the end of the adhesive layer. By doing so, it is possible to prevent the thickness of the adhesive layer from being increased as a whole, thereby suppressing a decrease in the overall rigidity (static strength) of the reactor core 10.

  FIGS. 4 and 5 show another embodiment of the I-type core 2 shown in FIG. 3, and the I-type core 2A shown in FIG. It is a core formed into a truncated cone shape.

  On the other hand, the I-type core 2B shown in FIG. 5 is a core formed in a truncated pyramid shape in which the shape of the opposing surface is the most protruding at a central rectangular portion. In addition, although illustration is abbreviate | omitted, the shape of the opposing surface may be the cone shape or the pyramid shape which protruded most in the center part. Furthermore, when the generated shear stress is greatly different for each end portion of the adhesive layer, the thickness of the end portion of the adhesive layer can be changed for each portion, and the most protruding portion is the portion of the adhesive layer. The embodiment may be biased from the center to one side.

  FIG. 7 is a longitudinal sectional view of another embodiment of a reactor core. In this embodiment, instead of forming the opposing surfaces of the I-type core 2 and the U-type core 1 into ridges, the opposing surface of the gap plate 3A protrudes in a curved shape, and the opposing surface is a flat I-type core 2C. And a reactor core having a U-shaped core 1A. Further, although not shown, the combined form of FIGS. 6 and 7, that is, the opposing surfaces of the I-type core and the U-type core are protruded in a curved shape, and the opposing surfaces of the gap plate also protrude in a curved shape. It may be a form to be made.

  8 and 9 are diagrams illustrating an outline of a molding method when molding a core material from a dust core. The molding method shown in FIG. 8 includes, for example, a hollow die 51 that defines a cavity for I-shaped core molding, a lower punch 53 and an upper punch 52 that close the hollow end portion and move relative to the die 51. For example, the temperature of the die 51 is adjusted to 120 ° C., the soft magnetic powder is filled in the cavity, and the soft magnetic powder is placed from above and below by the lower punch 53 and the upper punch 52. Pressurization is performed under the condition of a pressure of 1226 MPa (X direction in the drawing), and the lower punch 53 and the upper punch 52 are moved in this pressing posture to perform die cutting (Y direction in the drawing).

  When the powder magnetic core pressed under the above-mentioned pressurizing conditions is punched out, the side swells outward by the vertical pressure as shown in the figure (Z direction in the figure), and automatically A protrusion on the opposite surface can be formed. In addition, removing the mold while pressing with the upper and lower punches eliminates the problem of multi-layer cracks on the side of the core material, which was a problem in the conventional die-cutting method in the non-pressurized state. can do.

  On the other hand, in the mold shown in FIG. 9, for example, of the upper and lower punches 52A and 53A fitted to the hollow die 51, for example, a protruding shape of the core material is formed on the cavity facing surface of one upper punch 52A. By providing the concave mold 52A1, it is possible to mold a core material having a predetermined shape at the same time as the punching from the upper and lower punches 52A and 53A. In FIG. 9, the I-type core 2B is molded.

  The core material manufactured by the above manufacturing method and the gap plate are accommodated in a pressure device (not shown) in a posture in which an adhesive layer is interposed between the core material and bonded in a posture pressurized by a pressure means. By waiting for the solidification of the agent, a reactor core in which the core material and the gap plate are bonded and fixed with an adhesive layer having a predetermined thickness can be manufactured. In this method, the longitudinal part of the reactor core (part consisting of the I-type core and the gap plate) is manufactured separately, and finally the longitudinal part and the U-type core are bonded and fixed via the gap plate and the adhesive layer. Also good.

[Outline and results of thermal cycle test and shear test]
Next, the thermal cycle test and the shear test by the inventors will be described below. 10A and 10B, a part of the test piece T of the reactor core of the present invention shown in FIGS. 10a and 10b and a part of the test piece T ′ of the conventional reactor core shown in FIG. 10c are prepared. Cycle conditions (one cycle shown in the figure) are executed for a predetermined cycle, and the test pieces T and T ′ that have undergone a predetermined cooling / heating cycle are now subjected to shear fracture using the shear fracture test equipment shown in FIG. The stress was measured and the result is shown in FIG.

  The test piece T shown in FIGS. 10a and 10b is composed of an I-type core piece T1, a gap plate piece T3, and an adhesive layer T2. The width of the gap plate piece T3: L3 is 2.3 mm, and the I-type core piece T1 and adhesive layer T2. The total width: L1 is 20.9 mm, and the height of the I-type core piece T1 and the gap plate piece T3: L2 is 20 mm. The thickness of the end portion of the adhesive layer T2: t2 is set to a predetermined value within a range of 0.07 to 0.13 mm, and the thickness at the center: t1 is set to a predetermined value within a range of 0.025 to 0.05 mm. .

  On the other hand, the test piece T ′ shown in FIG. 10C is composed of an I-type core piece T1 ′, a gap plate piece T3 ′, and an adhesive layer T2 ′, and has the same dimensions as the test piece T, but the thickness t3 of the adhesive layer T2 ′. Is uniformly set to a predetermined value within a range of 0.025 to 0.05 mm.

  FIG. 11 shows the temperature history (the dotted line in the graph) in the furnace in which the test pieces T and T ′ are placed, and the bonded portions of the test pieces T and T ′ (for example, the ends of the I-type core piece T1 and the adhesive layer T2). The temperature history (solid line in the graph) of the bonded part) is shown. The temperature in the furnace is such that the temperature is lowered from 150 ° C. to −40 ° C. after 40 minutes, and then raised to 150 ° C. again after 40 minutes.

  The test pieces T and T ′ having undergone the above-mentioned cycle for a predetermined cycle are fixed to the shear fracture number test apparatus A shown in FIG. 12, and for example, as shown in the figure, the shear strength is set between the I-type core piece T1 and the adhesive layer T2. Push the punch in a measurable posture (Z direction) and measure the shear strength.

  FIG. 13 shows the experimental results. The thermal cycle test was performed in three cases of 0, 50, and 150 cycles, and the shear stress at the time of rupture was measured with a plurality of test pieces T and T ′, respectively.

  As a result of the experiment, when the number of cycles is 0, the test piece T ′ having a thin adhesive layer as a whole has a self-evident result in which the shear stress is higher. In the case of 50 and 100 cycles, The shear strength of the test piece T ′ is almost close to 0, whereas the test piece T is 20 MPa or more in the case of 50 cycles and about 10 to 20 MPa in the case of 100 cycles, which is compared with the conventional reactor core. As a result, it was proved that the cooling durability was remarkably improved.

[Shear stress analysis (static analysis) and results when the thickness of the adhesive layer is changed]
In this analysis, as shown in FIG. 14, a three-dimensional model M composed of an I-type core model M1, a gap plate model M3, and an adhesive layer model M2 composed of a mesh is created. Node: 9500, Element: 8208, and the constraint condition was a condition where 6 degrees of freedom were freely constrained, and the material property values were analyzed under the conditions shown in Table 1 below. In this analysis, the model size in FIG. 14 (L4: 21.7 mm to 22 mm, L5: 20 mm, L6: 22 mm) was used, and the thickness of the adhesive layer was changed in four cases. In each case, δ1 at the center is fixed at 0.05 mm. In case 1, δ2 is 0.05 mm, in case 2, δ2 is 0.1 mm, in case 3, δ2 is 0.2 mm, and in case 4, δ2 is 0. The analysis result regarding the shear stress of the outer peripheral part of the adhesive layer under the temperature conditions of 150 ° C. and −40 ° C. was obtained. This analysis is a static analysis and does not take into account the cooling / heating cycle.

  FIG. 15 shows the analysis result under the temperature condition of 150 ° C., and FIG. 16 shows the analysis result under the temperature condition of −40 ° C., respectively.

  From FIG. 15, as the thickness of the adhesive layer end is increased, the decrease in the generated shear stress value is remarkable, and the thickness of the end is smaller than in case 1 where the thickness of the adhesive layer is 0.05 mm. When the thickness was 0.4 mm, the shear stress was reduced by about 30%.

  On the other hand, even in the case of the temperature condition of −40 ° C., the shear stress was reduced by about 30%.

  From the above thermal cycle endurance test and shear fracture test, and the results of three-dimensional FEM analysis, reducing the generated shear stress due to the temperature difference by increasing the thickness of the edge compared to the center of the adhesive layer, shearing It has been demonstrated that the resistance to fracture can be increased.

  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 perspective view of the reactor core of the present invention. It is a perspective view of the reactor which comprises the reactor door of FIG. It is a perspective view of one embodiment of a core material. It is a perspective view of other embodiment of a core material. It is a perspective view of other embodiment of a core material. It is a longitudinal cross-sectional view of a rear anchor. It is a longitudinal cross-sectional view of other embodiment of a reactor tank. It is the schematic diagram which showed one Embodiment of the manufacturing method of a reactor tank. It is the schematic diagram which showed other embodiment of the manufacturing method of a reactor tank. (A) is a perspective view of a part of the test piece of the reactor core of the present invention used for the shear test, (b) is a bb arrow view of (a), (c) is a conventional reactor. It is a test piece that is part of the core. It is the graph explaining the conditions of 1 cycle of a thermal cycle test. It is the schematic diagram explaining the outline | summary of the shear fracture test. It is the graph which showed the shear fracture test result. It is a perspective view of the FEM analysis model used for the shear stress analysis (static analysis) at the time of changing the thickness of an adhesive bond layer. It is the graph which showed the shear stress analysis result (150 degreeC). It is the graph which showed the shear stress analysis result (-40 degreeC).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A ... U type core, 2,2A, 2B, 2C ... I type core, 3,3A ... Gap board, 4 ... Adhesive layer, 10 ... Reactor core, 20 ... Coil, 30 ... Reactor

Claims (5)

A core material having a plurality of magnets and a non-magnetic gap plate interposed between adjacent core materials, the opposing surface of the core material and the opposing surface of the gap plate being interposed via an adhesive layer Reactor that is fixed,
Of the opposing surfaces of both the core material and the gap plate , at least the opposing surface of the gap plate is formed in a protruding shape with the center or substantially center of the opposing surface protruding most, and the thickness of the adhesive layer is bonded. Reactor that is thicker from the center of the surface or from the center to the end.   The reactor core according to claim 1, wherein the protruding shape of the facing surface is formed in a curved shape.   The reactor core according to claim 1, wherein the projecting shape of the opposing surface is a truncated cone.   The reactor core according to claim 1, wherein the protruding shape of the facing surface is a truncated pyramid shape.   A reactor comprising the reactor core according to any one of claims 1 to 4.

Images