JP5314569B2 - Magnetic element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic element that can sufficiently secure insulation between a composite magnetic member and a winding, and is manufactured easily. <P>SOLUTION: The winding is inserted into a lower case 3 and then an upper case 1 is fitted. In this case, a terminal 2a of the winding is made to pass through a hole 1b formed at a projection of the upper case 1 and drawn to the outside of a case 50 to obtain a winding member 8, and the winding member 8 is casted by a composite magnetic body. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a magnetic element in which a composite magnetic member and a winding are integrally formed by casting, and particularly used for a booster circuit of an inverter that is a power conversion device for a vehicle driving power motor such as an electric vehicle or a hybrid vehicle. In particular, the present invention relates to a magnetic element such as a reactor corresponding to large current application or high voltage application.

  Conventionally, this type of magnetic element generally has a configuration in which a composite magnetic member containing a metal magnetic material powder and an insulating resin encloses a winding and draws the winding to form a terminal portion. As a composite magnetic member, a specific resistance of several Ωcm or more is required to prevent an eddy current from flowing between magnetic powders contained in order to reduce iron loss. However, under a high voltage of several hundred volts or more, the composite magnetic member itself Since insulation is low, it is important to have a reliable insulation structure between the composite magnetic member formed in close contact with the winding.

  In addition, since the magnetic element can be formed into a free shape and the winding and the magnetic member can be formed in close contact with each other, the space loss is minimized and the size can be reduced, but the insulation structure is too thick. When the outer diameter of the product is constant, the volume of the composite magnetic member required to obtain the magnetic performance of the magnetic element decreases, and the effective magnetic path length increases due to the increased outer circumference of the winding. Therefore, it is important to make the insulating structure as thin and reliable as possible.

  In addition, in order to cope with applications in harsh environments, consideration is given to heat, vibration, etc., and from the viewpoint of the spread of environmentally friendly products in the future, magnetic elements by a lower cost manufacturing method are required.

  Incidentally, a magnetic element in which a composite magnetic member and a winding are integrally formed is known as this type of technology (Patent Document 1 (FIGS. 1-8)).

  In addition, in the case of equipment for ultra-high pressure, in order to ensure insulation, an insulating material such as an insulating pipe is once loaded around the coil, and then a ferromagnetic material such as iron powder and a fixing agent such as a resin are injected. A technique for performing molding is known (Patent Document 2 (page 5, upper left column, lines 8-12)).

  Also known is a method in which other members such as a plate-shaped or ring-shaped spacer are partially sandwiched between the mold, the mold and the winding are positioned, and casting is performed in a state where the thickness is secured ( Patent Document 3 (paragraphs 0019-0027).

  In addition, as a molded coil, a molded coil or inner winding formed by curing a thermosetting resin composition containing an inorganic filler on a winding obtained by winding a conductor coated with an electrical insulator around a bobbin. An integrated molded coil is known in which the periphery of the outer winding arranged coaxially with respect to the outer periphery is formed by being cured after casting with a thermosetting resin composition containing an inorganic filler (Patent Document 4). wrap up)).

JP 2001-185421 A Japanese Patent Laid-Open No. 48-1724 JP 2006-4957 A JP 2003-257750 A

  However, in the technique disclosed in Patent Document 1, there is a possibility that defects such as partial flaws and pinholes may exist in the insulating film previously applied to the wire of the winding. If particles such as metal contained in the member approach, insulation failure may occur, and management of manufacturing requires considerable consideration, especially in the case of an element to which a voltage of several hundred volts is applied. Specifically, it is desirable to have a withstand voltage of several thousand volts, and it is necessary to provide a further insulating layer.

  Moreover, in the technique disclosed in Patent Document 2, it is difficult to reliably cover the entire surface of the winding wire enclosed by the insulating pipe including the terminal portion without any gap just by loading the insulating pipe. There was a risk of insufficient insulation from the member. Also, in such a structure, there is a gap between the insulating pipe and the winding, resulting in a decrease in heat dissipation, and the insulating pipe and the winding are not fixed, and the winding is worn due to external vibration or the like. There was a risk of further damage.

  In addition, methods such as casting, injection molding, and transfer molding are known as methods for molding while integrally including an insulating layer so as to cover the entire outer surface of the winding. In these methods, it is difficult to mold while accurately arranging and maintaining the position of the mold and the winding at the time of molding, and because of the positional deviation between the winding and the mold, a thick portion or There is a possibility that a thin part may occur, and defects such as bubbles and cracks may occur, and considerable care is required for manufacturing management. Here, in the magnetic element of the casting method in which the composite magnetic member and the winding are integrally molded, if the member that insulates the surface of the winding is thick, to obtain the magnetic performance of the magnetic element under a constant outer diameter of the product Since the volume of the required composite magnetic member is reduced, and the effective magnetic path length is increased due to the increase in the outer circumference of the winding, adverse effects such as a decrease in inductance occur. Therefore, the thickness of the insulating member is 0.3 to 2 mm. It is desirable to set the degree. However, when molding a thin gap as described above in pressure molding such as injection molding, since the injection pressure becomes as high as several hundred MPa, there is a possibility that problems such as deformation of the winding itself may occur. Yes, it is difficult to apply.

  By the way, in the technique disclosed in Patent Document 3, when the elastic modulus and the linear expansion coefficient of the spacer used and the injected insulator are different, thermal stress is applied, or the adhesive force is not good depending on the surface state of the adhesive surface. If it is sufficient, the insulation will be degraded due to the peeling of the interface, etc., so considerable care is required for production management.

  In order to improve the insulation, it is conceivable to use a plurality of insulating layers. However, the cost increases due to an increase in the number of processing steps, and the thickness of the insulating layer is increased by the minimum thickness required for each method. Therefore, the magnetic performance of the element is lowered, which is not preferable.

  In addition, there is a method of coating the winding with insulating resin, but the minimum thickness required for insulation may not be ensured reliably, and defects such as bubbles may occur, making the process complicated, such as the need for multi-layer coating This is not preferable.

  Further, in the technique disclosed in Patent Document 4, these molded coils are premised on application to devices such as general transformers that have a space from the magnetic core, and include composite magnetic members including terminals. It did not have a reliable insulation performance in a structure in which is closely formed.

  An object of the present invention is to solve the above-mentioned problems and to provide a magnetic element that can sufficiently ensure insulation between a composite magnetic member and a winding and can be easily manufactured.

  In order to solve the above-described problems, the present invention provides a magnetic element using a casting method in which a composite magnetic member and a winding are integrally formed, and the entire surface of the surface where the winding contacts the composite magnetic member is an insulator. The magnetic element is covered and stored in a case. The case is divided into two or more pieces, and the divided portions are magnetic elements fitted so as to overlap each other in a form in which a winding is housed. The case has at least two protrusions, and the protrusion protrudes to the outside of the composite magnetic member in a magnetic element obtained by casting and solidifying the composite magnetic member. A magnetic element having a hole through which a terminal at a location can penetrate and be drawn out. A magnetic element having an insulating structure is characterized in that an insulating resin is filled in a gap between the case and the housed winding. The hole of the protruding portion of the case is a magnetic element having an insulating structure characterized in that it has a shape through which a winding can penetrate and has a flow path for filling the insulating resin.

  The insulation structure is vacuum-impregnated in a state where the case is attached to a winding and is immersed in the insulating resin up to above the hole of the case, and the insulating resin is injected into the case and then heat-cured. The magnetic element has a structure.

That is, according to the present invention, in the magnetic element in which the composite magnetic member and the winding are integrally formed by casting, the entire surface where the winding is in contact with the composite magnetic member is covered and stored by the case made of an insulator. The case has at least two protruding portions that protrude to the outside of the composite magnetic member, and the protruding portion has a hole through which the end of the winding passes with a clearance. In addition, a magnetic element having an extended portion that is formed by extending a part of the inner surface in the width or radial direction and serves as a flow path when the insulating resin is filled can be obtained.

  According to the present invention, there is provided the above magnetic element, wherein the case is divided into at least two members, and the members are fitted to overlap each other in a state where the winding is housed. It is done.

  According to the present invention, there is obtained the above magnetic element, wherein the gap between the case and the winding is filled with an insulating resin.

Further, according to the present invention, the insulating resin is injected into the case from the hole by vacuum impregnation in a state where the winding is housed in the case and the position of the hole is in the liquid of the insulating resin. The above-described magnetic element characterized by being heat-cured can be obtained .

  According to the magnetic element of the present invention, in the insulating structure of the magnetic element by the casting method in which the composite magnetic member and the winding are integrally formed, the insulation case in which the minimum thickness necessary for insulation is secured and the case is filled. The entire surface of the winding is insulated from the composite magnetic member by the insulated resin, and at the same time, there are no defects such as bubbles or an interface that may decrease the insulation, such as the interface with the spacer. By impregnating with an insulating resin, it is possible to easily obtain a winding insulating structure that can withstand a voltage of several thousand volts.

  In addition, since the case is filled with insulating resin, heat dissipation is not reduced, and an insulating structure that does not cause the winding to be worn or damaged by external vibrations can be easily obtained. be able to.

It is a perspective view of the upper case concerning Example 1 of the present invention. It is a perspective view of the winding which concerns on Example 1 of this invention. It is a perspective view of the lower case concerning Example 1 of the present invention. It is a perspective view of the state which attached the case to the coil which concerns on Example 1 of this invention. It is explanatory drawing of the state which attached the case to the coil which concerns on Example 1 of this invention, Fig.5 (a) is a top view, FIG.5 (b) is a front view. It is a top view which shows the shape of the hole of the upper case protrusion part which concerns on Example 1 of this invention, FIG.6 (a) is a figure which shows the shape of the hole which does not have an extended part, FIG.6 (b) shows an extended part. It is a figure which shows the shape of the hole which has. It is sectional drawing which shows typically the insulating structure which concerns on Example 1 of this invention. It is sectional drawing of the magnetic element which concerns on Example 1 of this invention. 9A and 9B are cross-sectional views of an insulating structure according to Examples 2 and 3 of the present invention. FIG. 9A is a diagram illustrating Example 2, and FIG. FIG. 10A is a cross-sectional view of an insulating structure according to Examples 4 and 5 of the present invention, FIG. 10A is a diagram illustrating Example 4, and FIG.

  Hereinafter, embodiments of the present invention will be described in detail. A magnetic element according to an embodiment of the present invention includes a winding member housed in a lower case and filled with an insulating resin and covered with an upper case, a composite magnetic member casting the same, and these It consists of an outer case.

  In the present invention, as the composite magnetic member, for example, an iron-based magnetic powder such as Fe-Si-based or Fe-Si-Al-based and a liquid resin such as thermosetting can be mixed to form a slurry. Iron-based magnetic powders contain a non-ferrous component and have a composition that reduces saturation magnetostriction and magnetocrystalline anisotropy, and iron loss can be reduced, but conversely as the non-ferrous component increases, the saturation magnetic flux density decreases and the magnetic element Therefore, the non-ferrous component species and content are appropriately selected depending on the application. The thermosetting resin is preferably a low-viscosity resin so as to have sufficient fluidity when made into a slurry. In addition, the mechanical properties of the thermosetting resin after curing, such as elastic modulus, fracture strength, and elongation at break, are sufficient for heat generation due to energizing conditions used as magnetic elements and temperature rise due to usage environment, cooling mechanism, etc. It is necessary to have heat resistance and cold resistance and not to break due to thermal stress. For example, an epoxy resin having a high breaking strength or a silicone resin having a high breaking elongation can be used.

  In the present invention, a wound wire is a rectangular wire wound in an edgewise shape, which has a high space factor and is suitable for downsizing, but may be a wire wound with a round wire. Further, the winding shape of the winding is generally circular, but is not limited to this, and may be an ellipse or a rectangle having a rounded corner.

  The material of the case in the present invention is such that the mechanical properties such as elastic modulus, breaking strength, elongation at break have sufficient heat resistance against heat generation due to energizing conditions used as a magnetic element and temperature rise due to usage environment, cooling mechanism, etc. Any material can be used as long as it has a cold resistance and does not easily break due to thermal stress, and can be easily broken by handling such as assembly with a winding wire and fitting. For example, PBT, LCP, 6 nylon or the like can be used. Moreover, it is desirable that the filler appropriately contains a filler to improve the thermal conductivity.

  The case of the present invention is separated into two pieces, for example, an upper cylinder (hereinafter referred to as an upper case) and a lower cylinder (hereinafter referred to as a lower case) when the outer diameter is substantially cylindrical and the rotational symmetry axis of the cylinder is placed vertically. The upper case is formed by integrating the outer cylinder facing the outer periphery of the winding, the inner cylinder facing the inner periphery of the winding, and the top plate, and the lower case is the outer facing the outer periphery of the winding. The cylinder, the inner cylinder facing the inner periphery of the winding, and the bottom plate are integrally formed. The upper case and the lower case are fitted so as to overlap each other, and if the fitting length is too short, it is difficult to check whether they are fitted in the manufacturing process. Is desirable. Further, in order to facilitate the fitting operation, it is desirable that the end portions of the inner and outer cylindrical portions of the upper and lower cases are chamfered. The case can be divided into three or more. For example, the side portion may be formed as a simple cylindrical shape and fitted to the upper and lower cases during assembly. Further, the cylinder may have a double configuration of inner and outer sides and may be divided into four parts.

  Here, the top plate of the upper case has two protruding portions upward, and the protruding portion protrudes to the outside of the composite magnetic member in a magnetic element obtained by casting and solidifying the composite magnetic member. The protruding portion has a hole through which two ends of the winding can penetrate and be pulled out. When the hole has a clearance of about 0 to 0.5 mm with respect to the wire cross section of the winding, the end of the winding is held and fixed at a desired position, and the assembly with the mating terminal to which the terminal is connected is possible. improves.

  In addition, the hole has a shape along the wire strand cross section so that the end of the winding is in the desired position range, but it does not have to be along the entire circumference, and part of the hole is extended to the outside. The insulating resin can be vacuum impregnated in the case fitted with the extended portion as the flow path. As a result, the winding is completely housed in the case, and an insulation structure without any direct contact with the composite magnetic member including the terminal part is obtained, and the outer surface and inner surface of the case and the fitting part are made of insulating resin. Since it is filled, the insulation can be further improved.

  If a flat wire is wound in an edgewise shape and the winding axis is vertical, and the upper terminal is bent at a right angle so as to face upward, the remaining terminal is at the bottom. The upper end of the magnetic element is cast and solidified by casting the composite magnetic member when the lower end is bent at a right angle along the outer circumference of the winding and vertically pulled out, and in the same direction as the other end In this configuration, two terminals are arranged, and the workability of connection with other parts becomes easy. In this case, the case has a shape in which a part of the cylindrical shape projects so as to include the extended portion of the lower terminal. In addition, in a terminal part, a protrusion part can also be made into three or more places. For example, when there are two or more terminals such as a bifilar winding, a plurality of terminals may be pulled out from a hole in one protruding portion. Moreover, it is good also as a quantity according to the number of terminals. Further, the protruding portion may be divided into at least two places through which the winding passes and at least one place through which the resin flows. Moreover, you may provide the nonfunctional dummy which does not penetrate a winding and inflow of resin.

  In general, since the dielectric strength of the molding resin is around 20 kV / mm, a case thickness of 0.25 mm may be used to obtain a dielectric strength of 5 kV, which can withstand use at several hundred volts. The insulation thickness of the winding can be obtained stably and easily as compared with other molding methods.

The magnetic element of the Example of this invention is demonstrated with reference to drawings.
Example 1
FIG. 1 is a perspective view of an upper case according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of a winding according to the first embodiment of the present invention. FIG. 3 is a perspective view of the lower case according to the first embodiment of the present invention. FIG. 4 is a perspective view of a state where the case is mounted on the coil according to the first embodiment of the present invention. FIG. 5 is an explanatory diagram of a state where a case is mounted on the coil according to the first embodiment of the present invention, FIG. 5A is a plan view, and FIG. 5B is a front view.

  As shown in FIG. 2, the wire used is a flat copper wire with a thickness of 0.8 mm and a width of 9 mm, with an AIW coating applied, and has an inner diameter of 60 mm and is wound 32 turns in an edgewise shape, with two ends. The winding 2 was produced by bending the terminal 2a so that is in the upward direction. The dimensions of the winding 2 are an outer diameter of 78 mm, an inner diameter of 60 mm, and a height of 32 mm.

  Next, as shown in FIG. 3, the lower case 3 is made to have a thickness of 0.5 mm with a dimension enclosed by a winding and a clearance of 0.5 mm, and the material is made by cutting with a PBT material. As shown in FIG. 1, the upper case 1 is made of a PBT material with a thickness of 0.5 mm so as to be fitted to the lower case 3, and the upper case 1 has two protruding portions 1a each having a hole through which an element wire passes. A place was provided.

  Next, as shown in FIGS. 4 and 5, a winding was inserted into the lower case 3, and then the upper case 1 was fitted. At that time, the winding terminal 2 a was pulled out to the outside of the case 50 through the hole 1 b provided in the protruding portion of the upper case 1 to obtain the winding member 8.

  6 is a plan view showing the shape of the hole in the upper case protrusion according to the first embodiment of the present invention. FIG. 6 (a) is a diagram showing the shape of the hole having no extension, and FIG. 6 (b). FIG. 4 is a view showing a shape of a hole having an extended portion. As shown in FIG. 6, it provided in the protrusion part 1a of the upper case. The hole 1b is 0.3 mm larger than the end 2a of the winding, and an expansion portion 1c is provided as a flow path when vacuum impregnating with an insulating resin.

  FIG. 7 is a cross-sectional view schematically showing an insulating structure according to Example 1 of the present invention. In the first embodiment, as shown in FIG. 7, the upper case 1 is fitted to the outer side of the lower case 3 in the fitting shape of the upper and lower cases.

FIG. 8 is a cross-sectional view of the magnetic element according to Example 1 of the present invention. Next, as shown in FIG. 8, a mixture of a predetermined amount of a two-component mixed thermosetting epoxy resin XNR4455 and a curing agent XN1213 manufactured by Nagase ChemteX Corporation as a liquid insulating resin is taken in a container, and the upper case 1, A case in which the lower case 3 is mounted, immersed in a state in which the liquid level of the insulating resin is above the upper surface of the hole of the upper case 1, and vacuum-impregnated at a vacuum degree of 4.0 × 10 ² Pa to fit the insulating resin It was filled in and pulled up, and after removing excess liquid epoxy resin adhering to the outer surface of the case by air blow, it was cured at 120 ° C. for 3 hours.

  Example 1 After setting a winding obtained by curing an insulating resin filled inside and an upper and lower case to an aluminum case 5 as an outer case using a fixing member, the composite magnetic member 4 is cast and heat cured. Magnetic element 10 was obtained. The dimensions of the magnetic element are an outer diameter of 93 mm and a height of 51 mm. The composite magnetic member 4 has a predetermined ratio of Epicoat 827 and Cure W made by Japan Epoxy Resin Co., which is 60% by volume of gas atomized powder of Fe 6.5% Si as magnetic powder and the balance is a two-component mixed thermosetting epoxy resin. Made by mixing. The fixing member was prepared by curing the composite magnetic member 4 in a block shape in advance.

  Next, another embodiment is shown. 9 is a cross-sectional view of an insulating structure according to the second and third embodiments of the present invention. FIG. 9A is a diagram illustrating the second embodiment, and FIG. 9B is a diagram illustrating the third embodiment. FIG. 10 is a cross-sectional view of an insulating structure according to Examples 4 and 5 of the present invention. FIG. 10 (a) is a diagram showing Example 4 and FIG. 10 (b) is a diagram showing Example 5.

(Example 2)
As shown in FIG. 9A, the upper and lower cases were manufactured in the same manner as in Example 1 except that the upper case 11 was fitted inside the lower case 13.

(Example 3)
As shown in FIG. 9B, the upper case 21 was formed in the same manner as in Example 1 except that the outer peripheral end was doubled and the lower case 23 was fitted inside and outside.

Example 4
As shown in FIG. 10 (a), the upper case 31 and the lower case 33 were fitted in the middle in the vertical direction, and the others were produced in the same manner as in Example 1.

(Example 5)
As shown in FIG. 10 (b), the upper case 41 having a flat cross section was fitted to the upper part of the lower case 43, and the others were fabricated in the same manner as in Example 1.

(Comparative example)
As a comparative example, after the corner of the winding obtained in the same manner as in Example 1 was protected with a cap, a two-component mixed thermosetting epoxy resin XNR4455 and a curing agent XN1213 manufactured by Nagase ChemteX Corporation were used as the liquid insulating resin. Was then immersed in a predetermined amount of liquid, and after pulling it up, excess liquid epoxy resin adhering to the outer surface of the case was removed by air blow, and then cured at 120 ° C. for 3.5 hours. . Immersion and curing were repeated twice. The resulting resin-coated winding was cast in the same manner as in Example 1 to cast a composite magnetic member, and a magnetic element having the same dimensions as in Example 1 was produced.

  The insulation withstand voltage between the winding terminal of the magnetic element and the aluminum case according to the example and the comparative example manufactured as described above was measured using a withstand voltage tester KIKUUSUI WITHSTANDING VOLTAGE TESTER-IOS8700.

  As a result, in Examples 1 to 4, no breakdown occurred even at a voltage of 10 kV, and in Example 5, the breakdown voltage was 8 kV. In the comparative example, it was naturally not broken at 10 kV.

  In the examples of the present invention, as in the comparative example, all of the examples showed a high breakdown voltage, and a magnetic element having high insulation performance could be obtained.

  The embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

1, 11, 21, 31, 41 Upper case 1a Protruding portion 1b Hole 1c (along wire cross section) Expansion portion 2 Winding 2a (Winding) Terminals 3, 13, 23, 33, 43 Lower case 4 Composite magnetism Member 5 Aluminum case 6 Insulating resin 8 Winding member 10 Magnetic element 50 (upper and lower) case

Claims (4)

In the magnetic element in which the composite magnetic member and the winding are integrally formed by casting, the entire surface where the winding is in contact with the composite magnetic member is covered and stored with a case made of an insulator,
The case has at least two protrusions protruding to the outside of the composite magnetic member,
The protruding portion has a hole through which the end of the winding passes with a clearance,
The magnetic element according to claim 1, wherein the hole has an extended portion that is formed by extending a part of the inner surface in the width or radial direction and serves as a flow path when the insulating resin is filled.   The magnetic element according to claim 1, wherein the case is divided into at least two members, and the members are fitted to overlap each other in a state in which the winding is accommodated.   The magnetic element according to claim 1, wherein an insulating resin is filled in a gap between the case and the winding.   The winding is housed in the case, and the insulating resin is injected into the case from the hole and heat-cured by vacuum impregnation in a state where the hole is in the liquid of the insulating resin. The magnetic element according to claim 1.

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