Patent Grant
10366819
Field of the Invention
The present invention relates to a coil component and a method of manufacturing the same, and specifically, to a coil component with an air core without using a bobbin, and a method of manufacturing the same.
Description of the Related Art
As the performance of electronic equipment advances, high performance is required for components of the electronic equipment. Particularly, the computerization of automobiles progresses increasingly, and high performance is required is in demand for components used therein. For this reason, in recent years, a trend of the use of ferrite materials in the related art has been shifted to the use of metallic materials.
For example, Patent Literature 1 discloses a choke coil including an outer core which is a dust core, and of which at least an inner surface has a square frame shape; a bobbin which is mounted inside a frame of the outer core in a state where a coil is wound around the bobbin; an inner core that is a dust core, which is a magnetic core of the bobbin, has a shape of a core rod having a central axis parallel to the direction of a winding axis of the coil, and is inserted between two planes such that the central axis is perpendicular to the two planes which are the inner surface of the outer core and face each other; and a mold portion which is formed by filling a space between both end surfaces with resin, the outer core as the mold frame, and in which the coil and the bobbin are molded.
In an inductance element disclosed in Patent Literature 2, a coil is spirally wound by a rectangular flat metallic wire with a rectangular sectional shape so that one short side of the rectangular shape turns to the center side. Both end portions of the coil are lead outward from a wound portion. The outer circumference of the coil is covered with an insulating layer. Both end portions of the coil project outward from middle portions of two parallel side surfaces of a core which are positioned at the middle of the side surfaces in a height direction. Both end portions are first bent from the wound portion along the side surfaces of the core, and tip end portions of both end portions are bent along a back surface of the core. Since both end portions of the coil serve as terminals, both end portions are not covered with insulating layers. The core is manufactured by adding an insulating material into metal magnetic grains (Fe—Ni and the like), mixing together the insulating material and the metal magnetic grains, and applying pressure to the mixed material under predetermined conditions.
Since the coil disclosed in Patent Literature 1 uses a bobbin, the size of the coil cannot be reduced, which is a problem. On the other hand, Patent Literature 2 discloses an example in which a bobbin is not used. The magnetic element is configured such that an air-core coil is embedded into a magnetic body, and the air-core coil is in direct contact with the metallic magnetic body. For this reason, it is necessary to take high degree of insulation and the like into consideration, and therefore, a method of adjusting the composition of the metal magnetic grains or increasing the amount of resin in the magnetic body has been used. However, this countermeasure restricts an improvement of performance of the magnetic body. Also, if a high voltage is applied to the element, electricity passes through the inside of the magnetic body. For the above reasons, there have been no small and high-performance components which can be used without restriction of use which specifically can be used in a high voltage condition until now.
The present invention was made in light of these problems, and an object of the present invention is to provide a small and high-performance coil component which can be used in a circuit or the like to which a high voltage is applied without restriction of use, and to provide a method of manufacturing the same.
Any discussion of problems and solutions involved in the related art has been included in this disclosure solely for the purposes of providing a context for the present invention, and should not be taken as an admission that any or all of the discussion were known at the time the invention was made.
A coil component of the present invention is characterized in providing: an air-core coil that is formed of a winding part which winds a coated conductive wire and includes an inner circumferential surface, an outer circumferential surface, and a principle face of one end portion and a principle face of the other end portion in the direction of a winding core axis, and of a pair of leader parts which lead outward from the winding part; a first core member that includes a shaft part disposed inside the inner circumferential surface, a side wall portion disposed in at least a portion of the outer circumferential surface, and a connection portion which is disposed such that a first gap is formed between the principle face of the one end portion and the connection portion, and through which the shaft part is connected to the side wall portion, and that contains metal magnetic grains; and a second core member which is disposed such that a second gap is formed between the principle face of the other end portion and the second core member and which contains metal magnetic grains.
A main embodiment of the coil component is characterized by having: a third gap between the shaft part and the second core member, and a fourth gap between the side wall portion and the second core member which is larger in distance than the third gap. Another embodiment is characterized by having: a fifth gap between the leader parts and a side surface of the second core member. Furthermore, another embodiment is characterized in that the second core member is an E-type or I-type.
A method of manufacturing a coil component proposed by the present invention is characterized by comprising: a preparation step of obtaining a first core member of an E-type and a second core member of an E-type or an I-type by forming and heat-treating metal magnetic grains; another preparation step of obtaining an air-core coil which is formed of a winding part formed by winding a coated conductive wire, and of a pair of leader parts which lead outward from the winding part, and obtaining terminal electrodes electrically connected to the air-core coil; a step of installing the air-core coil in the second core member; a step of applying an adhesive to the second core member; a step of disposing the first core member such that the air-core coil is disposed between the second core member and the first core member; and a step of curing the adhesive.
A main embodiment is characterized in that the terminal electrodes are formed by installing the air-coil in the second core member after bending conductor portions that extend from the leader parts, or after connecting terminal members to the conductor portions via soldering or bending. Another embodiment is characterized in that a first gap is formed between the first core member and the air-core coil in an interposed manner, and a second gap is formed between the second core member and the air-core coil in an interposed manner. Yet another embodiment is characterized in that a fifth gap is provided between the second core member and the leader parts. The aforementioned objects, characteristics, and advantages and other objects, characteristics, and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.
According to the invention, it is possible to obtain a small and high-performance coil component with a high dielectric withstand voltage.
For purposes of summarizing aspects of the invention and the advantages achieved over the related art, certain objects and advantages of the invention are described in this disclosure. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.
Further aspects, features and advantages of this invention will become apparent from the detailed description which follows.
These and other features of this invention will now be described with reference to the drawings of preferred embodiments which are intended to illustrate and not to limit the invention. The drawings are greatly simplified for illustrative purposes and are not necessarily to scale.
A preferred embodiment of the present invention is described in detail below based on examples.
Initially, Example 1 of the present invention is described with reference to
First, the air-core coil 50 is described with reference to
Next, a specific example in which the terminal electrodes are formed via bending is described. As illustrated in
Alternatively, the terminal electrodes 60 and 62 illustrated in
Next, the second core member 20 is described with reference to
In this example, as described above, the side wall portion 24 is not formed in one side surface 27 of the second core member 20. This is because when the air-core coil 50 is installed in the second core member 20, the air-core coil 50 is inserted from the side surface 27 side, in such a way that the side surface 27 faces the leader parts 56 and 58 of the air-core coil 50. Also, the second core member 20 includes a bottom surface 29 on which the terminal electrodes 60 and 62 are disposed, and a tapered surface 28 is connected in the direction extending from the side surface 27 toward the bottom surface 29. A stepped portion 30 parallel to the bottom surface 29 may be provided between the side surface 27 and the tapered surface 28. The tapered surface 28 and the stepped portion 30 are formed to reduce a load applied when the air-core coil 50 is slid in a step (refer to
Next, an example of the first core member 40 is described with reference to
The second core member 20 and the first core member 40 are formed of metal magnetic grains. For example, a core which is a magnetic body is obtained by using metal magnetic grains of FeSiCr; adding a binder or the like; filling a die with metal magnetic grains; molding by applying pressure; and then heat-treating. The metal magnetic grains may be FeSiAl, or alloy particles containing Ni, Ti, and Co in addition to Si, Cr, and Al, and contain 92.5 wt % to 96 wt % of Fe, 4 wt % to 7.5 wt % of components other than Fe, and impurities other than the aforementioned components. Examples of the binder include PVA, PVB, and silicone, and a molding material is obtained by mixing the metal magnetic grains with a binder. Or, after the surfaces of metal magnetic grains are coated with glass, the metal magnetic grains may be mixed with a binder. Molding is performed using a die having a desired shape, and compact are obtained by applying a molding pressure of 6 ton/cm2 to 16 ton/cm2 to the molding material. Thereafter, the first core member 40 and the second core member 20 are obtained by removing the binder from the compact at a temperature of 200° C. to 300° C., and then heat treating them in oxidizing atmosphere at a temperature of 600° C. to 850° C.
The magnetic metallic grains are bonded together via oxide coatings such that the obtained core members 20 and 40 are formed. The oxide coating is a Si or Zr oxide coating, and a crystalline oxide coating may be provided on the outside of the oxide coating. Si or Zr oxide coatings increase a dielectric withstand voltage between the metal magnetic grains, and thus, it is possible to reduce a distance between the winding part 54 and the groove 48 in a first gap 72, and a distance between the winding part 54 and the groove 32 in a second gap 70. Also, the crystalline oxide coatings are capable of increasing bonding between the metal magnetic grains, and are to not only increase mechanical strength of the core members, but also to protect the Si or Zr oxide coatings, and are capable of preventing insulation degradation or the occurrence of rust. Also, the crystalline oxide coatings serve to prevent the oxidation of the surfaces of the metal magnetic grains, and as a result, prevent the occurrence of excessive oxidation, which makes it possible to reduce a change in the dimensions of the core members when being heat-treated. That is, the obtained core members have substantially the same dimensions as those of the compacts, and it is possible to obtain the core members with high dimensional accuracy while preventing the occurrence of a deformation caused by the heat treatment.
Next, a method of manufacturing the coil component 10 in the example is described with reference to
As described above, since the stepped portion 30 and the tapered surface 28 are provided in an edge portion of the bottom surface 29 of the second core member 20, when the air-core coil 50 is installed in the second core member 20 while being slid, a load applied during sliding is reduced. And, as illustrated in
In this example, as described above, the terminal electrodes 60 and 62 are formed from the leader parts 56 and 58 of the air-core coil 50 in advance, and then the air-core coil 50 is installed in the second core member 20. In contrast, in a coil component 10B illustrated in
Hereinafter, structural characteristics of the coil component in this example are described with reference to
Also, as illustrated in
According to Example 1, the following effects are obtained.
1) The air-core coil 50 includes the winding part 54 formed by winding the coated conductive wire 52, and the pair of leader parts 56 and 58 which lead outward from the winding part 54. The air-core coil 50 is interposed between the second core member 20 and the first core member 40, which are formed of metal magnetic grains, in the direction of a winding core axis of the winding part 54. Also, the pair of core members 20 and 40 are E-type cores which are configured to respectively include the shaft parts 22 and 42 disposed inside the winding part 54; the side wall portions 24 and 44 which interpose the winding part 54 between the shaft parts 22 and 42 and the side wall portions 24 and 44; and the connection portions 26 and 46 through which the shaft parts 22 and 42 are connected to the side wall portions 42 and 44. And, the upper surface 50A of the winding part 54 is not in contact with the first core member 40, and the bottom surface 50B of the winding part 54 is not in contact with the second core member 20. That is, the first gap 72 of a predetermined distance is provided between the first core member 40 and the air-core coil 50, and the second gap 70 of a predetermined distance is provided between the second core member 20 and the air-core coil 50. Accordingly, it is possible to obtain the coil component 10 which is small and has a high dielectric withstand voltage without using a bobbin or the like. The coil component in the example withstands a voltage load of 1 kV, and does not undergo dielectric breakdown in this voltage range. An adhesive is applied to at least one of the first gap 72 and the second gap 70. The use of the adhesive leads to a higher dielectric withstand voltage, and since the winding part 54 is fixed to the core members, it is possible to not only make the core component robust against impact, but also prevent the occurrence of vibration of a coil caused by the application of current to the coil after the coil component is mounted on a substrate.
2) Since the fifth gap 74 of a predetermined distance is provided between the leader parts 56 and 58 of the air-core coil 50 and the side surface 27 of the second core member 20, it is possible to reduce force occurring due to vibration or the like after the core component is mounted on the substrate, and it is possible to prevent the occurrence of an open circuit or the like. Also, it is possible to have flexibility of compensating for behavioral differences caused by a difference between the coefficients of thermal expansions of the members. Moreover, it is possible to prevent the leaking of current from the terminal electrodes 60 and 62 to the air-core coil 50 via the second core member 20 even if a sudden high voltage is applied.
3) Before the air-core coil 50 is installed in the cores, the terminal electrodes 60 and 62 are formed in advance from the conductive portions of the leader parts 56 and 58 via soldering or bending after the winding part 54 is formed in the air-core coil 50. For this reason, it is possible to increase dimensional accuracy of respective mounting surfaces of the terminal electrodes 60 and 62 with respect to the substrate, and as a result, in a case where a conductor having a large sectional area is used as the conductor 52, it is possible to reliably mount the coil component on the substrate.
4) Since the stepped portion 30 and the tapered surface 28 are provided on a bottom surface side of the second core member 20 on which the side surface 27 is positioned, it is possible to reduce a load applied when the air-core coil 50 is slid and installed in the second core member 20.
5) Since the dummy terminal 64 is provided on the bottom surface 29 of the second core member 20 to align with the height of the terminal electrodes 60 and 62, it is possible to maintain stability of the core component 10 during mounting.
The present invention is not limited to the aforementioned example, and changes can be made in various forms insofar as the changes do not depart from the concept of the present invention. For example, the following changes may be included.
1) The shapes, the dimensions, and the materials illustrated in the example are given as examples, and may be suitably changed whenever necessary.
2) In the example, the first gap 72 is provided between the winding part 54 of the air-core coil 50 and the first core member 40, the second gap 70 is provided between the winding part 54 and the second core member 20, and the fifth gap 74 is provided between the leader parts 56 and 58 of the air-core coil 50 and the side surface 27 of the second core member 20. In addition to providing those gaps, a magnetic gap may be provided between the second core member 20 and the first core member 40. For example, as in a coil component 10A illustrated in
3) In the example, the shaft part 22 of the second core member 20 has a substantially circular sectional shape which is given as an example; as in a second core member 20A illustrated in
4) The E-type core illustrated in the Example 1 is given as an example. When a section passing through the shaft part 22 of the second core member 20 is viewed, the second core member 20 may be shaped to have the side wall portions on both sides of the shaft part. For example, as an example illustrated in
5) Also, in a case where both core members are E-type cores as in Example 1, the heights of the shaft parts or the side wall portions of both core members are not necessarily required to be the same, and as in an example illustrated in
6) In the example, the conductor 52 forming the air-core coil 50 is a rectangular wire having a substantially rectangular sectional shape, which is given as an example, and various well-known conductors may be used.
According to the present invention, a coil component configured to include an air-core coil formed from a coated conductive wire, and two core members containing metal magnetic grains is suitably used as a small and high-performance coil component which does not use a bobbin or the like.
In the present disclosure where conditions and/or structures are not specified, a skilled artisan in the art can readily provide such conditions and/or structures, in view of the present disclosure, as a matter of routine experimentation. Also, in the present disclosure including the examples described above, any ranges applied in some embodiments may include or exclude the lower and/or upper endpoints, and any values of variables indicated may refer to precise values or approximate values and include equivalents, and may refer to average, median, representative, majority, etc. in some embodiments. Further, in this disclosure, “a” may refer to a species or a genus including multiple species, and “the invention” or “the present invention” may refer to at least one of the embodiments or aspects explicitly, necessarily, or inherently disclosed herein. The terms “constituted by” and “having” refer independently to “typically or broadly comprising”, “comprising”, “consisting essentially of”, or “consisting of” in some embodiments. In this disclosure, any defined meanings do not necessarily exclude ordinary and customary meanings in some embodiments.
The present application claims priority to Japanese Patent Application No. 2015-195267, filed Sep. 30, 2015, the disclosure of which is incorporated herein by reference in its entirety including any and all particular combinations of the features disclosed therein.
It will be understood by those of skill in the art that numerous and various modifications can be made without departing from the spirit of the present invention. Therefore, it should be clearly understood that the forms of the present invention are illustrative only and are not intended to limit the scope of the present invention.
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| A First Office Action issued by the State Intellectual Property Office of China dated Feb. 28, 2018 for Chinese counterpart application No. 201610873946.8. |
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| 20170092410 A1 | Mar 2017 | US |
