Molded magnetic core

Abstract

To provide a molded magnetic core that is suppressed from deformation and breakage.SOLUTION: A molded magnetic core includes a magnetic core, a collar, and a molded portion. The magnetic core is formed into a ring shape by winding a thin ribbon of magnetic material. The collar is a cylindrical body that has higher mechanical strength than the magnetic core when an external force is applied from the outer periphery toward the inner periphery. The collar is positioned on the inner periphery of the magnetic core and its outer periphery contacts the inner periphery of the magnetic core. The molded portion is made of a resin material and is positioned to cover at least both end faces and the outer periphery of the magnetic core.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a molded magnetic core. [Background technology]

[0002] A technique has been disclosed in which a closed magnetic circuit core (referred to as a magnetic core in this disclosure) made of an amorphous magnetic ribbon is resin-molded (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 58-56305 Summary of the Invention [Problem to be solved by the invention]

[0004] A magnetic core made by winding a thin ribbon of magnetic material has lower mechanical strength than a sintered body such as a ferrite core. Therefore, when resin-molding such a magnetic core, the magnetic core may be deformed or damaged by the pressure of the resin material when the resin material is injected into the mold in which the magnetic core is placed. If the magnetic core is deformed or damaged, its performance may be degraded.

[0005] In one aspect of the present disclosure, it is desirable to provide a molded magnetic core in which deformation and breakage of the magnetic core are suppressed. [Means for solving the problem]

[0006] (1) One aspect of the present disclosure is a molded magnetic core, comprising a magnetic core, a collar, and a molded portion. The magnetic core is formed into an annular shape by winding a thin ribbon of magnetic material. The collar is a cylindrical body having a higher mechanical strength than the magnetic core when an external force is applied from the outer periphery toward the inner periphery, and is disposed on the inner periphery of the magnetic core, with its outer periphery contacting the inner periphery of the magnetic core. The molded portion is made of a resin material and is positioned to cover at least both end faces and the outer periphery of the magnetic core.

[0007] In the molded magnetic core configured in this manner, the collar as described above is disposed on the inner periphery of the magnetic core. Therefore, the magnetic core is less likely to be crushed toward the center than if the collar were not disposed. Therefore, even if the magnetic core is subjected to pressure from the resin material when the molded portion is provided, the collar can suppress deformation and damage of the magnetic core, making it possible to provide a molded magnetic core in which deformation and damage of the magnetic core are suppressed.

[0008] The molded magnetic core of the present disclosure may further have the following configuration. (2) In one aspect of the present disclosure, the molded portion may be further formed at a position that covers both end surfaces and the inner peripheral surface of the collar.

[0009] (3) In one embodiment of the present disclosure, the magnetic material may be an Fe-based nanocrystalline alloy. (4) In one embodiment of the present disclosure, the collar may be made of one or more materials selected from thermoplastic resin, thermosetting resin, metal, glass, and ceramic. [Brief explanation of the drawings]

[0010] [Figure 1] 1A and 1B are perspective views of a molded magnetic core according to a first embodiment, as viewed from the upper right front and lower left rear, respectively. [Figure 2]Fig. 2A is a plan view of the molded magnetic core of the first embodiment. Fig. 2B is a front view of the molded magnetic core of the first embodiment. Fig. 2C is a bottom view of the molded magnetic core of the first embodiment. Fig. 2D is a cross-sectional view of the molded magnetic core of the first embodiment taken along line IID-IID in Fig. 2B. [Figure 3] Fig. 3A is a perspective view of the molded magnetic core of the second embodiment as seen from the upper right front, and Fig. 3B is a perspective view of the molded magnetic core of the second embodiment as seen from the lower left rear. [Figure 4] Fig. 4A is a plan view of the molded magnetic core of the second embodiment, Fig. 4B is a front view of the molded magnetic core of the second embodiment, Fig. 4C is a bottom view of the molded magnetic core of the second embodiment, and Fig. 4D is a cross-sectional view of the molded magnetic core of the second embodiment taken along line IVD-IVD in Fig. 4B. [Figure 5] Fig. 5A is a perspective view of the molded magnetic core of the third embodiment as seen from the upper right front, and Fig. 5B is a perspective view of the molded magnetic core of the third embodiment as seen from the lower left rear. [Figure 6] Fig. 6A is a plan view of a molded magnetic core of the third embodiment. Fig. 6B is a front view of the molded magnetic core of the third embodiment. Fig. 6C is a right side view of the molded magnetic core of the third embodiment. Fig. 6D is a cross-sectional view of the molded magnetic core of the third embodiment taken along the line VID-VID in Fig. 6C. [Figure 7] Fig. 7A is a perspective view of the molded magnetic core of the fourth embodiment as seen from the upper right front, and Fig. 7B is a perspective view of the molded magnetic core of the fourth embodiment as seen from the lower left rear. [Figure 8] Fig. 8A is a plan view of the molded magnetic core of the fourth embodiment, Fig. 8B is a front view of the molded magnetic core of the fourth embodiment, Fig. 8C is a bottom view of the molded magnetic core of the fourth embodiment, and Fig. 8D is a cross-sectional view of the molded magnetic core of the fourth embodiment taken along line VIIID-VIIID in Fig. 8B. DETAILED DESCRIPTION OF THE INVENTION

[0011] Next, the above-mentioned molded magnetic core will be described with reference to exemplary embodiments. (1) First embodiment First, the first embodiment will be described.

[0012] [Configuration of molded magnetic core] As shown in Figures 1A, 1B, 2A, 2B, 2C, and 2D, the molded magnetic core 1 includes a magnetic core 11, a collar 13, and a molded portion 15. The left side view, right side view, and rear view of the molded magnetic core 1 are the same as the front view (see Figure 2B). In the following explanation, to simply explain the relative positions of the various parts of the molded magnetic core 1, the left, right, front, rear, top, and bottom of the molded magnetic core 1 are defined as follows:

[0013] The left of the molded magnetic core 1 is the direction that the part that appears in the left side view of the molded magnetic core 1 faces. The right of the molded magnetic core 1 is the direction that the part that appears in the right side view of the molded magnetic core 1 faces. The front of the molded magnetic core 1 is the direction that the part that appears in the front view of the molded magnetic core 1 (see Figure 2B) faces. The rear of the molded magnetic core 1 is the direction that the part that appears in the rear view of the molded magnetic core 1 faces. The top of the molded magnetic core 1 is the direction that the part that appears in the plan view of the molded magnetic core 1 (see Figure 2A) faces. The bottom of the molded magnetic core 1 is the direction that the part that appears in the bottom view of the molded magnetic core 1 (see Figure 2C) faces.

[0014] The magnetic core 11 is an annular body formed by winding a thin ribbon of a magnetic material. In this embodiment, the magnetic material forming the magnetic core 11 is an Fe-based nanocrystalline alloy. Collar 13 is a cylindrical body that has higher mechanical strength than magnetic core 11 when an external force is applied from the outer periphery toward the inner periphery. Collar 13 is disposed on the inner periphery of magnetic core 11, and the outer periphery of collar 13 contacts the inner periphery of magnetic core 11. Collar 13 is made of a heat-resistant resin material (glass fiber-reinforced PPS (heat-resistant temperature 230°C-250°C) in this embodiment) that is heat-resistant enough not to deform under the temperature conditions used to mold molded portion 15. In the first embodiment, both vertical end surfaces of collar 13 are configured to be flush with both vertical end surfaces of molded portion 15.

[0015] The molded portion 15 is made of a resin material (a thermoplastic polyamide resin material in this embodiment). The resin material used to form the molded portion 15 is preferably a resin material that can be injection molded at low pressure (for example, about 0.3 MPa to 5 MPa). The molded portion 15 is provided in a position that covers both end faces and the outer peripheral surface of the magnetic core 11. However, portions of both end faces and the outer peripheral surface of the magnetic core 11 that are not covered by the molded portion 15 may remain.

[0016] For example, in the present embodiment, six through holes 17 are formed in molded portion 15. Through holes 17 penetrate molded portion 15 and reach the end face of magnetic core 11. In other words, the end face of magnetic core 11 is exposed to the outside at the locations where through holes 17 are formed, and these exposed locations correspond to locations that are not covered by molded portion 15.

[0017] [Manufacturing method for molded magnetic cores] Next, a method for manufacturing the molded magnetic core 1 will be described. A ribbon of Fe-based amorphous metal is wound to form a ring-shaped body, which is then placed in a furnace and heat-treated in a magnetic field to promote crystallization of the Fe-based amorphous metal, producing a nanocrystalline alloy magnetic core 11. A collar 13 is attached to the inner periphery of the magnetic core 11, and the magnetic core 11 and collar 13 are placed in a mold (not shown). The mold has a lower mold and an upper mold, with one boss and three pins protruding into the molding space of the lower mold, and one boss and three pins protruding into the molding space of the upper mold.

[0018] The magnetic core 11 and collar 13 are placed in a lower mold, and at this time, a boss in the lower mold is fitted into the inner periphery of the collar 13, and the tips of the three pins in the lower mold abut against the end face of the magnetic core 11. Next, the upper mold is lowered to close the mold, and the boss in the upper mold is fitted into the inner periphery of the collar 13, and the tips of the three pins in the upper mold abut against the end face of the magnetic core 11. Next, a resin material is injected into the mold to form the molded portion 15.

[0019] Once the resin material that will become molded portion 15 has solidified, the mold is opened, and an ejector pin built into the lower mold ejects molded magnetic core 1 from the lower mold. When the mold is opened, the upper mold rises, and the three pins inside the upper mold are pulled out from molded portion 15. Furthermore, when molded magnetic core 1 is ejected from the lower mold, the three pins inside the lower mold are pulled out from molded portion 15. The above-mentioned through holes 17 are traces left by the pins that were pulled out from molded portion 15.

[0020] [effect] According to the molded magnetic core 1 configured as above, the collar 13 as described above is arranged on the inner periphery of the magnetic core 11. Therefore, the magnetic core 11 is less likely to be crushed toward the center than when the collar 13 is not arranged. Therefore, during the manufacture of the molded magnetic core 1, even if the magnetic core 11 is subjected to pressure from the resin material when the molded portion 15 is formed, the collar 13 can prevent the magnetic core 11 from being deformed or damaged.

[0021] The inner peripheral surface of magnetic core 11 is covered by collar 13, and both end faces and the outer peripheral surface of magnetic core 11 are covered by molded portion 15. That is, except for the area where through hole 17 is formed, magnetic core 11 is housed inside the structure formed by collar 13 and molded portion 15. Therefore, when molded magnetic core 1 is in use, even if the molded magnetic core 1 comes into contact with an object, the object can be prevented from coming into direct contact with magnetic core 11, and damage to magnetic core 11 can be suppressed.

[0022] One method for suppressing damage to the magnetic core 11 is to house the magnetic core 11 in a case instead of providing the molded portion 15 described above. However, housing the magnetic core 11 in a case requires a space between the case and the magnetic core 11, which increases the size of the case and the dimensions of the final product. Furthermore, if there is a space like the above, the magnetic core 11 will rattle inside the case, which may cause damage to the magnetic core 11. While rattle can be suppressed by filling the space with a sealant, the use of such a sealant increases material costs and the number of steps required to fill the sealant.

[0023] In this regard, if the molded portion 15 as described above is provided, unlike a case, the aforementioned space for play is not required, and therefore the dimensions of the final product can be made smaller than when the magnetic core 11 is housed in a case. In addition, since the aforementioned rattle does not occur, damage to the magnetic core 11 due to rattle does not occur, and filling with a sealing material as described above is also unnecessary.

[0024] (2) Second embodiment Next, a second embodiment will be described. The second and subsequent embodiments will be described in detail, focusing on the differences from the first embodiment.

[0025] As shown in Figures 3A, 3B, 4A, 4B, 4C, and 4D, the molded magnetic core 2 includes a magnetic core 21, a collar 23, and a molded portion 25. Six through holes 27 are formed in the molded portion 25. The left side view, right side view, and back view of the molded magnetic core 2 are the same as the front view (see Figure 4B).

[0026] The magnetic core 21 is configured in the same manner as the magnetic core 11 of the first embodiment. The shape of collar 23 is different from that of collar 13 of the first embodiment. Specifically, in the second embodiment, collar 23 is a partially cylindrical member having a C-shaped cross section perpendicular to the up-down direction. More specifically, in the case of the second embodiment, collar 23 has a shape equivalent to a partially cylindrical member in which a 315° range is left and a 45° range is removed from the full 360° circumferential range of the cylindrical body.

[0027] The molded portion 25 is made of the same resin material as the molded portion 15 of the first embodiment. In the case of the second embodiment, the molded portion 25 is formed in a position that covers part of the inner circumference of the magnetic core 21, in addition to being formed in the same location as the molded portion 15 of the first embodiment. More specifically, the inner circumference of the magnetic core 21 is covered by the collar 23 over the above 315° range, while the molded portion 25 covers the above 45° range.

[0028] The molded magnetic core 2 configured as described above also provides the same functions and effects as the molded magnetic core 1 exemplified in the first embodiment. That is, during the manufacture of the molded magnetic core 2, even if the magnetic core 21 is subjected to pressure from the resin material when forming the molded portion 25, the collar 23 can prevent deformation or breakage of the magnetic core 21. When the molded magnetic core 2 is in use, the collar 23 and the molded portion 25 can prevent damage to the magnetic core 21. Furthermore, the dimensions of the final product can be made smaller than when the magnetic core 21 is housed in a case, damage to the magnetic core 21 due to rattles within the case does not occur, and filling with a sealant to prevent rattles is also unnecessary.

[0029] (3) Third embodiment Next, a third embodiment will be described. As shown in Figures 5A, 5B, 6A, 6B, 6C, and 6D, the molded magnetic core 3 includes a magnetic core 31, a collar 33, and a molded portion 35. Eight through holes 37 are formed in the molded portion 35. The left side view of the molded magnetic core 3 is the same as the right side view (see Figure 6C). The back view of the molded magnetic core 3 is the same as the front view (see Figure 6B). The bottom view of the molded magnetic core 3 is the same as the plan view (see Figure 6A).

[0030] The magnetic core 31 has a different shape from the magnetic core 11 of the first embodiment. Specifically, the magnetic core 31 of the third embodiment is configured so that the cross section perpendicular to the up-down direction has an oval shape. The oval shape here refers to a shape in which semicircular portions are provided at both ends in the left-right direction, and linear portions extending in the left-right direction are provided between the front ends and rear ends of the two semicircular portions.

[0031] The shape of the collar 33 is different from that of the collar 13 of the first embodiment. Specifically, the collar 33 of the third embodiment is configured so that the cross-sectional shape perpendicular to the up-down direction is oval, in accordance with the shape of the magnetic core 31.

[0032] The molded portion 35 has a different shape from the molded portion 15 of the first embodiment. Specifically, the molded portion 35 of the third embodiment is configured so that the cross section perpendicular to the up-down direction has an oval shape in accordance with the shape of the magnetic core 31. Also, the number of through holes 37 is different from that of the first embodiment.

[0033] The molded magnetic core 3 configured as described above also provides the same functions and effects as the molded magnetic core 1 exemplified in the first embodiment. That is, during the manufacture of the molded magnetic core 3, even if the magnetic core 31 is subjected to pressure from the resin material when forming the molded portion 35, the collar 33 can prevent deformation or breakage of the magnetic core 31. When the molded magnetic core 3 is in use, the collar 33 and the molded portion 35 can prevent damage to the magnetic core 31. Furthermore, the dimensions of the final product can be made smaller than when the magnetic core 31 is housed in a case, damage to the magnetic core 31 due to rattles within the case does not occur, and filling with a sealant to prevent rattles is also unnecessary.

[0034] (4) Fourth embodiment Next, a fourth embodiment will be described. As shown in Figures 7A, 7B, 8A, 8B, 8C, and 8D, the molded magnetic core 4 includes a magnetic core 41, a collar 43, and a molded portion 45. Six through holes 47 are formed in the molded portion 45. The left side view, right side view, and back view of the molded magnetic core 4 are the same as the front view (see Figure 8B).

[0035] The magnetic core 41 has the same configuration as the magnetic core 11 of the first embodiment. The collar 43 has a different vertical dimension from the collar 13 of the first embodiment. Specifically, in the first embodiment, the vertical dimension of the collar 13 is configured to match the vertical dimension of the molded magnetic core 1, but in the fourth embodiment, the vertical dimension of the collar 43 is configured to match the vertical dimension of the magnetic core 11.

[0036] The molded portion 45 is made of the same resin material as the molded portion 15 of the first embodiment. In the case of the fourth embodiment, the molded portion 45 is formed in the same locations as the molded portion 15 of the first embodiment, and also in positions that cover both the upper and lower end surfaces of the collar 43 and the inner peripheral surface of the collar 43. In other words, the molded portion 45 is formed in positions that cover both the magnetic core 41 and the collar 43.

[0037] The molded magnetic core 4 configured as described above achieves the same functions and effects as the molded magnetic core 1 exemplified in the first embodiment. That is, during the manufacture of the molded magnetic core 4, even if the magnetic core 41 is subjected to pressure from the resin material when forming the molded portion 45, the collar 43 can prevent deformation or breakage of the magnetic core 41. When the molded magnetic core 4 is in use, the collar 43 and the molded portion 45 can prevent damage to the magnetic core 41. Furthermore, the dimensions of the final product can be made smaller than when the magnetic core 41 is housed in a case, damage to the magnetic core 41 due to rattles within the case does not occur, and filling with a sealant to prevent rattles is also unnecessary.

[0038] (5) Other embodiments While the molded magnetic core has been described above using exemplary embodiments, the above-described embodiments are merely examples of one aspect of the present disclosure. In other words, the present disclosure is not limited to the above-described exemplary embodiments, and can be embodied in various forms without departing from the technical spirit of the present disclosure.

[0039] For example, the constituent material of the collar is not limited to the above-mentioned example, and may be made of one or more materials selected from the group consisting of thermoplastic resin, thermosetting resin, metal, glass, and ceramic.

[0040] Furthermore, the material of the molded portion is not limited to polyamide-based materials, as long as it is a resin material that can be used to form the molded portion. Note that multiple functions realized by one component exemplified in the above embodiments may be realized by multiple components. One function realized by one component exemplified in the above embodiments may be realized by multiple components. Multiple functions realized by multiple components exemplified in the above embodiments may be realized by one component. One function realized by multiple components exemplified in the above embodiments may be realized by one component. Part of the configuration exemplified in the above embodiments may be omitted. At least part of the configuration exemplified in one of the above embodiments may be added to or replaced with a configuration exemplified in an embodiment other than that one embodiment.

[0041] For example, the oval molded magnetic core 3 as exemplified in the third embodiment may employ a collar with a C-shaped cross section as exemplified in the second embodiment. Also, the oval molded magnetic core 3 as exemplified in the third embodiment may employ a molded portion that covers both end faces and the inner peripheral surface of the collar as exemplified in the fourth embodiment.

[0042] (6) Technical Ideas Disclosed in This Specification [Item 1] a magnetic core formed into an annular shape by winding a thin ribbon of magnetic material; a collar, which is a cylindrical body having a mechanical strength higher than that of the magnetic core when an external force is applied from the outer periphery toward the inner periphery, and which is disposed on the inner periphery side of the magnetic core and whose outer periphery surface contacts the inner periphery surface of the magnetic core; a molded portion made of a resin material and provided at a position covering at least both end surfaces and an outer peripheral surface of the magnetic core; A molded magnetic core comprising:

[0043] [Item 2] The molded magnetic core according to item 1, The molded portion is further formed at a position covering both end surfaces and an inner peripheral surface of the collar. Molded magnetic core.

[0044] [Item 3] The molded magnetic core according to item 1 or 2, The magnetic material is an Fe-based nanocrystalline alloy. Molded magnetic core.

[0045] [Item 4] The molded magnetic core according to any one of items 1 to 3, The collar is made of one or more materials selected from thermoplastic resin, thermosetting resin, metal, glass, and ceramic. Molded magnetic core. [Explanation of symbols]

[0046] 1, 2, 3, 4...molded magnetic core, 11, 21, 31, 41...magnetic core, 13, 23, 33, 43...collar, 15, 25, 35, 45...molded portion, 17, 27, 37, 47...through hole.

Claims

1. a magnetic core formed into an annular shape by winding a thin ribbon of magnetic material; a collar, which is a cylindrical body having a mechanical strength higher than that of the magnetic core when an external force is applied from the outer periphery toward the inner periphery, and which is disposed on the inner periphery side of the magnetic core and whose outer periphery surface contacts the inner periphery surface of the magnetic core; a molded portion made of a resin material and provided at a position covering at least both end surfaces and an outer peripheral surface of the magnetic core; A molded magnetic core comprising:

2. The molded magnetic core according to claim 1, The molded portion is further formed at a position covering both end surfaces and an inner peripheral surface of the collar. Molded magnetic core.

3. The molded magnetic core according to claim 1 or 2, The magnetic material is an Fe-based nanocrystalline alloy. Molded magnetic core.

4. The molded magnetic core according to claim 1 or 2, The collar is made of one or more materials selected from thermoplastic resin, thermosetting resin, metal, glass, and ceramic. Molded magnetic core.

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