Noise filter

Abstract

[Problem] To provide a noise filter which has higher heat rejection performance than conventional products and which is capable of suppressing temperature increases even when portions including conductors are reduced in size. [Solution] A noise filter is provided with a magnetic core, a conductor, a molded part, and a heat conduction part. The molded portion is made of a first thermally conductive material. The heat conduction part is formed of a second heat conduction material having a higher heat conductivity than the first heat conduction material, and is disposed so as to be in contact with an external member serving as a heat extraction destination when the noise filter is in use. An opening part penetrating through the molding part and reaching the outer peripheral surface of the magnetic body core is formed in the molding part. The heat conduction part is provided with an entering part entering the opening part and is configured to be in contact with the magnetic body core through the entering part.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a noise filter. BACKGROUND

[0002] A noise filter as disclosed in the following Patent Literature 1 is proposed. The noise filter described in the following Patent Literature 1 is provided with a magnetic core and a conductor (electrically conductive strip in the following Patent Literature 1), and a part of these magnetic core and conductor is molded with a resin material.

[0003] PRIOR ART DOCUMENTS PATENT LITERATURE Patent Literature 1: Japanese Patent Application Publication No. 2020-5043 SUMMARY

[0004] PROBLEMS TO BE SOLVED BY THE INVENTION The noise filter as described above becomes a part of a power supply path to a motor that becomes a power source, for example, in an electric automobile, a hybrid automobile, and the like. In such a use, a large current flows through the conductor, and the conductor accordingly generates heat. If the magnetic core becomes excessively high temperature along with the heat generation of the conductor, it can have an adverse effect on the performance of the noise filter. In addition, if the noise filter becomes excessively high temperature, in a case where electronic parts and the like exist in the vicinity of the noise filter, it can have an adverse effect on the performance of the electronic parts and the like. Therefore, it is important to appropriately suppress the heat generation of the noise filter.

[0005] As one method for suppressing the heat generation of the conductor, for example, a measure of making the conductor thick can be considered. However, in this case, the noise filter can be caused to be large, and it is difficult to arrange the noise filter to a narrow place. In addition, if the noise filter is made large, the weight of an apparatus provided with the noise filter can also increase. In addition, in order to cope with the heat, an air cooling mechanism or a water cooling mechanism can be added, but this also requires a space for arranging the air cooling mechanism or the water cooling mechanism, and thus it is difficult to arrange to a narrow place, and the weight can also increase.

[0006] In one aspect of the present disclosure, it is desirable to provide a noise filter whose heat radiation performance is higher than that of existing products, and which can suppress temperature rise even in a case where each part including the conductor is miniaturized.

[0007] MEANS FOR SOLVING THE PROBLEMS (1) One aspect of the present disclosure is a noise filter including a magnetic core, a conductor, a molding portion, and a heat transfer portion. The magnetic core is a magnetic body configured in a ring shape or a cylindrical shape. The conductor is disposed so as to pass through an inner peripheral side of the magnetic core. The molding portion is made of a first heat conductive material and molds a portion of the magnetic core and a portion of the conductor. The heat transfer portion is made of a second heat conductive material having a higher thermal conductivity than the first heat conductive material, is disposed so as to be in contact with a portion of the magnetic core and a portion of the molding portion, and is disposed so as to be in contact with an external member that is a heat dissipation destination when the noise filter is used, thereby transferring heat of the magnetic core and the molding portion to the external member. An opening portion that reaches an outer peripheral surface of the magnetic core through the molding portion is formed in the molding portion. The heat transfer portion has an entry portion that enters the opening portion and is configured to be in contact with the magnetic core through the entry portion.

[0008] According to the noise filter thus configured, the molding portion is made of the first heat conductive material, and the heat transfer portion is made of the second heat conductive material. Therefore, when the temperature of the magnetic core and the conductor rises, heat of the magnetic core and the conductor can be released to the molding portion and the heat transfer portion, and excessive temperature rise of the magnetic core and the conductor can be suppressed.

[0009] In particular, the entry portion of the heat transfer portion enters the opening portion formed in the molding portion and is in contact with the magnetic core. Therefore, heat of the magnetic core can be directly transferred to the heat transfer portion, and the heat transfer efficiency to the external member that is the heat dissipation destination can be improved as compared with a portion where the molding portion is interposed between the magnetic core and the heat transfer portion.

[0010] Therefore, the conductor can be allowed to generate heat more than the existing product in accordance with an amount by which the heat dissipation performance of the noise filter is increased, and thus a conductor that is thinner and more likely to generate heat than the existing product can be used. Thus, the noise filter can be downsized.

[0011] Note that the noise filter of the present disclosure can also be arbitrarily configured as follows.

[0012] (2) In one aspect of the present disclosure, the heat transfer portion can be configured to be in contact with an inner peripheral surface of the opening portion.

[0013] (3) In one aspect of the present disclosure, the heat transfer portion can be configured to form a gap between the heat transfer portion and the inner peripheral surface of the opening portion.

[0014] (4) In one aspect of the present disclosure, the first heat conductive material can have a thermal conductivity of 1 W / m·K or more and less than 1.4 W / m·K. The second heat conductive material can have a thermal conductivity of 1.4 W / m·K or more and 5 W / m·K or less.

[0015] (5) In one embodiment of the present disclosure, the heat conduction part may be configured such that when the noise filter is used, the heat conduction part deforms and thus comes into close contact with the external component when it is sandwiched between the magnetic core and the external component and / or between the molded part and the external component and subjected to a compressive load. Attached Figure Description

[0016] FIG. 1 A is a perspective view of the noise filter according to the first embodiment. FIG. 1 B is the noise filter of the first embodiment in FIG. 2C A cross-sectional view of the section cut off as shown by the IB-IB line. FIG. 1 C is the noise filter of the first embodiment in FIG. 2B A cross-sectional view of the section shown by the IC-IC line in the middle, when it has been cut.

[0017] FIG. 2A This is a top view of the noise filter according to the first embodiment. FIG. 2B This is a front view of the noise filter according to the first embodiment. FIG. 2C This is a right-side view of the noise filter according to the first embodiment. FIG. 2D This is a bottom view of the noise filter according to the first embodiment.

[0018] FIG. 3A The noise filter of the first embodiment is in FIG. 2C The section shown by the IB-IB line is cut off, and the heat conduction part is then exposed in a cross-sectional view. FIG. 3B The noise filter of the first embodiment is in FIG. 2B The section shown by the IC-IC line is cut off, thus revealing the heat conduction portion in a cross-sectional view. FIG. 3C This is a perspective view illustrating the usage state of the noise filter according to the first embodiment.

[0019] FIG. 4A The noise filter of the second embodiment is in FIG. 2C A cross-sectional view of the section cut off as shown by the IB-IB line. FIG. 4B The noise filter of the second embodiment is in FIG. 2B A cross-sectional view of the section shown by the IC-IC line in the middle, when it has been cut. FIG. 4C yes FIG. 4A An enlarged view of the IVC section shown. FIG. 4D yes FIG. 4A An enlarged view of the IVD section shown. FIG. 4E yes FIG. 4B An enlarged view of the IVE section shown. FIG. 4F yes FIG. 4B An enlarged view of the IVF section shown.

[0020] FIG. 5A is a perspective view of the noise filter of the third embodiment. FIG. 5B is a cross-sectional view of the case where the noise filter of the third embodiment is cut at the cut position indicated by the line VB-VB in FIG. 24. FIG. 6C is a cross-sectional view of the case where the noise filter of the third embodiment is cut at the cut position indicated by the line VB-VB in FIG. 24. FIG. 5C is a cross-sectional view of the case where the noise filter of the third embodiment is cut at the cut position indicated by the line VC-VC in FIG. 25. FIG. 6B is a cross-sectional view of the case where the noise filter of the third embodiment is cut at the cut position indicated by the line VC-VC in FIG. 25.

[0021] FIG. 6A is a plan view of the noise filter of the third embodiment. FIG. 6B is a front view of the noise filter of the third embodiment. FIG. 6C is a right side view of the noise filter of the third embodiment. FIG. 6D is a bottom view of the noise filter of the third embodiment.

[0022] BRIEF DESCRIPTION OF DRAWINGS 1, 21, 31,... noise filter; 3 magnetic core; 3A outer peripheral surface; 5 conductor; 5A, 5B through hole; 7 molded portion; 7A opening portion; 9 heat conduction portion; 9A first surface; 9B second surface; 11A, 11B fixing portion; 13A, 13B collar; 15 entry portion; 17 external member; 23 gap; 33A, 33B fin. DETAILED DESCRIPTION

[0023] Next, the above-described noise filter will be described with reference to exemplary embodiments.

[0024] (1) First Embodiment [Configuration of noise filter] As shown in FIG. 1 A, FIG. 1 B, FIG. 1 C, FIG. 2A , FIG. 2B , FIG. 2C and FIG. 2D , the noise filter 1 of the first embodiment has a magnetic core 3, a conductor 5, a molded portion 7, and a heat conduction portion 9. Note that the left side view and the right side view (see FIG. 2C ) of the noise filter 1 are shown as the same. The rear view and the front view (see FIG. 2B ) of the noise filter 1 are shown as the same.

[0025] As shown in FIG. 1 B and FIG. 1 C, the magnetic core 3 is a magnetic body configured in a ring shape or a cylindrical shape. As shown in FIG. 1 B andFIG. 1 As shown in Figure C, conductor 5 is configured to penetrate the inner periphery of magnetic core 3. In this embodiment, conductor 5 is configured as an elongated plate in the front-back direction as shown in the figure, with its thickness direction facing the vertical direction as shown in the figure. Through holes 5A and 5B, which penetrate in the thickness direction, are formed near both ends of conductor 5 in the long dimension direction (front-back direction as shown in the figure).

[0026] The molding part 7 is made of a first thermally conductive material. In this embodiment, the first thermally conductive material is selected with a thermal conductivity of 1 W / m·K or higher and less than 1.4 W / m·K, and a volume resistivity greater than 1.0 × 10⁻⁶. 13 A thermally conductive resin with an Ω·m conductivity (trade name: ZITOTM (registered trademark), manufactured by UNITIKA Co., Ltd.). The molding section 7 molds a portion of the magnetic core 3 and a portion of the conductor 5. The space between the inner periphery of the magnetic core 3 and the outer periphery of the conductor 5 is filled by the molding section 7.

[0027] The molding part 7 has fixing parts 11A and 11B that protrude in the left-right direction as shown in the figure. Metal collars 13A and 13B are provided in the fixing parts 11A and 11B. When the noise filter 1 is fixed to the mounting object by bolts (not shown), the bolt shaft passes through the collars 13A and 13B.

[0028] The heat-conducting part 9 is made of a second thermally conductive material with a higher thermal conductivity than the first thermally conductive material. In this embodiment, the second thermally conductive material is selected with a thermal conductivity of 1.4 W / m·K or higher and 5 W / m·K or lower, and a volume resistivity greater than 1.0 × 10⁻⁶. 11 The thermally conductive resin with an Ω·m and a hardness (ASKER C) preferably of 5 to 50 (more preferably 30 to 50) is (trade name: CPLK, manufactured by Kitagawa Industrial Co., Ltd.).

[0029] The heat-conducting part 9 is configured to contact a portion of the magnetic core 3 and a portion of the molding part 7. More specifically, as... FIG. 3A and FIG. 3B As shown, an opening 7A is formed in the molding portion 7. The opening 7A penetrates the molding portion 7 and reaches the outer peripheral surface 3A of the magnetic core 3. The heat conduction portion 9 has an inlet portion 15 protruding upward as shown in the figure. The heat conduction portion 9 is configured such that a first surface 9A located at the top end of the protruding direction of the inlet portion 15 is in contact with the magnetic core 3, and a second surface 9B located around the inlet portion 15 is in contact with the molding portion 7. Furthermore, in this embodiment, the inlet portion 15 is configured to also be in contact with the inner peripheral surface of the opening 7A.

[0030] When using noise filter 1, such as FIG. 3CAs shown, the heat conducting portion 9 is arranged so as to be in contact with an external member 17 (for example, a water-cooled cooling plate) that is a heat discharge destination, and conducts heat from the magnetic core 3 and the molding portion 7 to the external member 17. When the heat conducting portion 9 is compressed between the magnetic core 3 and the external member 17 and / or between the molding portion 7 and the external member 17, the heat conducting portion 9 deforms so as to be in close contact with the external member 17. Thus, compared to a case where the heat conducting portion 9 does not easily deform, heat movement from the heat conducting portion 9 to the external member 17 is promoted.

[0031] Note that in the present embodiment, the thermal conductivities of the first and second heat conductive materials described above are measured using a commercially available thermal disk method thermal physical property measurement device (TPS-500, manufactured by Kyoto Electronics Manufacturing Co., Ltd.) by a measurement method based on ISO 22007-2. Further, the volume resistivities of the first and second heat conductive materials described above are measured using a commercially available high-precision resistivity meter (MCP-HT450, manufactured by Mitsubishi Chemical Corporation) by a measurement method based on JIS K 6911.

[0032] [Effects] According to the noise filter 1 configured as described above, the molding portion 7 is composed of the first heat conductive material, and the heat conducting portion 9 is composed of the second heat conductive material. Thus, when the temperature of the magnetic core 3 and the conductor 5 rises, heat of the magnetic core 3 and the conductor 5 can be released to the molding portion 7 and the heat conducting portion 9, and excessive temperature rise of the magnetic core 3 and the conductor 5 can be suppressed.

[0033] In particular, the entry portion 15 of the heat conducting portion 9 enters the opening portion 7A formed in the molding portion 7 and is in contact with the magnetic core 3. Thus, heat of the magnetic core 3 can be directly conducted to the heat conducting portion 9, and heat conduction efficiency to the external member 17 that is a heat discharge destination can be improved compared to a portion where the molding portion 7 is interposed between the magnetic core 3 and the heat conducting portion 9.

[0034] Further, in the present embodiment, the entry portion 15 is in contact with the inner peripheral surface of the opening portion 7A. Thus, at the inner peripheral surface of the opening portion 7A, heat movement from the molding portion 7 to the heat conducting portion 9 occurs, and heat discharge from the molding portion 7 can be promoted.

[0035] Thus, the temperature rise of the noise filter 1 can be suppressed compared to a conventional product, in an amount corresponding to the increase in heat discharge performance of the noise filter 1. Alternatively, in a case where the temperature rise of the noise filter 1 can be allowed to be the same as that of the conventional product, the conductor 5 can be allowed to generate heat more than the conventional product. In this case, for example, a thinner conductor 5 that generates heat easily can be employed than the conventional product, and thus the noise filter 1 can be downsized.

[0036] Thus, the temperature rise of the noise filter 1 can be suppressed compared to a conventional product, in an amount corresponding to the increase in heat discharge performance of the noise filter 1. Alternatively, in a case where the temperature rise of the noise filter 1 can be allowed to be the same as that of the conventional product, the conductor 5 can be allowed to generate heat more than the conventional product. In this case, for example, a thinner conductor 5 that generates heat easily can be employed than the conventional product, and thus the noise filter 1 can be downsized.(2) Second Embodiment Next, the second embodiment will be described. It should be noted that the subsequent embodiments are modifications of a portion of the configuration illustrated in the first embodiment. Therefore, a detailed description will focus on the differences from the first embodiment. Configurations identical to those in the first embodiment will be labeled with the same reference numerals as in the first embodiment, and detailed descriptions thereof will be omitted.

[0037] [Configuration of noise filter] like FIG. 4A and FIG. 4B As shown, the structure of the noise filter 21 in the second embodiment, as shown in the cross-sectional view of the noise filter 21, differs from that of the noise filter 1 in the first embodiment. More specifically, as... FIG. 4C , FIG. 4D , FIG. 4E as well as FIG. 4F As shown, the noise filter 21 of the second embodiment differs from the noise filter 1 of the first embodiment in that it has a gap 23 between the molding part 7 and the heat conduction part 9.

[0038] In the first embodiment, the gap 23 is formed in FIG. 3A and FIG. 3B The opening 7A shown is located between the inner periphery and the outer periphery of the inlet 15. In the second embodiment, the magnetic core 3, conductor 5, and molding portion 7 are configured in the same shape and size as in the first embodiment. In the second embodiment, with FIG. 3A and FIG. 3B Compared to the inlet portion 15 of the first embodiment shown, the shape and size of the heat conduction portion 9 are configured such that the front-to-back dimension and the left-to-right dimension are smaller, as shown in the figure, thereby forming the aforementioned gap 23.

[0039] It should be noted that even when observing the appearance of the noise filter 21 of the second embodiment, the gap 23 is located in a position that cannot be seen. Therefore, the six-view diagram of the noise filter 21 of the second embodiment is exactly the same as the six-view diagram of the noise filter 1 of the first embodiment.

[0040] [Effects] Even if the noise filter 21 is configured as above, it functions and effects the same as the noise filter 1 explained in the first embodiment. Therefore, the temperature rise of the noise filter 21 can be suppressed compared with the existing product, in correspondence with the amount by which the heat dissipation performance of the noise filter 21 becomes higher. Or, in the case where the temperature rise of the noise filter 21 can be allowed to the same degree as the existing product, the conductor 5 can be allowed to generate heat more than the existing product. In this case, for example, a thinner conductor 5 which generates heat easily can be employed than the existing product, and thus miniaturization of the noise filter 21 can be sought.

[0041] Further, in the case of the second embodiment, the noise filter 21 has the gap 23 as explained above between the molded portion 7 and the heat conducting portion 9. Therefore, compared with the first embodiment, the second embodiment more easily embeds the entry portion 15 toward the inner periphery side of the opening portion 7A, and the productivity of the noise filter 21 can be improved.

[0042] (3) Third Embodiment Next, the third embodiment will be explained.

[0043] As FIG. 5A , FIG. 5B , FIG. 5C , FIG. 6A , FIG. 6B , FIG. 6C and FIG. 6D indicate, the noise filter 31 of the third embodiment is different from the noise filter 1 of the first embodiment in that it has the heat sinks 33A, 33B. The heat sinks 33A, 33B are integrally formed with the molded portion 7 by the first heat conducting material which configures the molded portion 7.

[0044] [Effects] Even if the noise filter 31 is configured as above, it functions and effects the same as the noise filter 1 explained in the first embodiment. Therefore, the temperature rise of the noise filter 31 can be suppressed compared with the existing product, in correspondence with the amount by which the heat dissipation performance of the noise filter 31 becomes higher. Or, in the case where the temperature rise of the noise filter 31 can be allowed to the same degree as the existing product, the conductor 5 can be allowed to generate heat more than the existing product. In this case, for example, a thinner conductor 5 which generates heat easily can be employed than the existing product, and thus miniaturization of the noise filter 31 can be sought.

[0045] Further, in the case of the third embodiment, the noise filter 31 has the heat sinks 33A, 33B as explained above. Thereby, heat dissipation from the heat sinks 33A, 33B can be promoted, and the heat dissipation performance of the noise filter 21 can be improved compared with the case where the same heat sinks are not provided.

[0046] (4) Other Embodiments The above-described exemplary embodiments have been described for the noise filter, but the above-described embodiments are merely examples of one aspect of the present disclosure. That is, the present disclosure is not limited to the above-described exemplary embodiments, and can be implemented in various ways without departing from the technical idea of the present disclosure.

[0047] For example, in the above-described embodiments, the first thermal conductive material and the second thermal conductive material that are combined with the constituent components in a specific composition ratio are exemplified, but the specific components and the composition ratio of the first thermal conductive material and the second thermal conductive material are not limited to the above-described examples.

[0048] Further, for example, in the above-described third embodiment, an example in which the heat sinks 33A and 33B are additionally provided on both sides in the front-rear direction of the molded portion 7 is shown, but the same heat sinks can be additionally provided on both sides in the left-right direction of the upper surface side of the molded portion 7.

[0049] Note that a plurality of functions that are implemented by one constituent element exemplified in the above-described embodiments can be implemented by a plurality of constituent elements. One function that is implemented by one constituent element exemplified in the above-described embodiments can be implemented by a plurality of constituent elements. A plurality of functions that are implemented by a plurality of constituent elements exemplified in the above-described embodiments can be implemented by one constituent element. One function that is implemented by a plurality of constituent elements exemplified in the above-described embodiments can be implemented by one constituent element. A part of the configuration exemplified in the above-described embodiments can be omitted. At least a part of the configuration exemplified in one of the above-described embodiments can be added to or replaced with the configuration exemplified in another of the above-described embodiments.

[0050] (5) Technical Ideas Disclosed in This Specification [Item 1] A noise filter includes: a magnetic core configured in a ring shape or a cylindrical shape; a conductor configured to pass through an inner peripheral side of the magnetic core; a molded portion configured to mold a part of the magnetic core and a part of the conductor, the molded portion being composed of a first thermal conductive material; and a thermal conductive portion configured to contact a part of the magnetic core and a part of the molded portion, the thermal conductive portion being composed of a second thermal conductive material having a higher thermal conductivity than the first thermal conductive material, the thermal conductive portion being configured to conduct heat of the magnetic core and the molded portion to an external member that is a heat dissipation destination in use of the noise filter, An opening portion reaching an outer circumferential surface of the magnetic core through the molding portion is formed in the molding portion, The heat conducting portion has an entering portion that enters the opening portion, and is configured to be in contact with the magnetic core through the entering portion.

[0051] [Item 2] The noise filter according to any one of items 1 to 4, wherein The heat conducting portion is configured to be in contact with an inner circumferential surface of the opening portion.

[0052] [Item 3] The noise filter according to any one of items 1 to 4, wherein The heat conducting portion is configured to form a gap between itself and an inner circumferential surface of the opening portion.

[0053] [Item 4] The noise filter according to any one of items 1 to 4, wherein The thermal conductivity of the first heat conducting material is 1 W / m·K or more and less than 1.4 W / m·K, The thermal conductivity of the second heat conducting material is 1.4 W / m·K or more and 5 W / m·K or less.

[0054] [Item 5] The noise filter according to any one of items 1 to 4, wherein The heat conducting portion is configured to deform so as to be in close contact with the external member when the heat conducting portion is compressed by a compression load when the heat conducting portion is sandwiched between the magnetic core and the external member and / or between the molding portion and the external member at the time of use of the noise filter.

Claims

1. A noise filter comprising: a magnetic core configured in a ring shape or a cylindrical shape; a conductor configured to pass through an inner peripheral side of the magnetic core; a molded portion configured of a first thermally conductive material, and molded on a portion of the magnetic core and a portion of the conductor; and a thermally conductive portion configured of a second thermally conductive material having a higher thermal conductivity than the first thermally conductive material, and configured to be in contact with a portion of the magnetic core and a portion of the molded portion, wherein, in use of the noise filter, the thermally conductive portion is configured to be in contact with an external member that is a heat dissipation destination, and to conduct heat of the magnetic core and the molded portion to the external member, an opening portion is formed in the molded portion to reach an outer peripheral surface of the magnetic core, the thermally conductive portion has an entry portion that enters the opening portion, and the thermally conductive portion is configured to be in contact with the magnetic core through the entry portion.

2. The noise filter according to claim 1, wherein the thermally conductive portion is configured to be in contact with an inner peripheral surface of the opening portion.

3. The noise filter according to claim 1, wherein the thermally conductive portion is configured to form a gap between the thermally conductive portion and the inner peripheral surface of the opening portion.

4. The noise filter according to any one of claims 1 to 3, wherein the first thermally conductive material has a thermal conductivity of 1 W / m-K or more and less than 1.4 W / m-K, and the second thermally conductive material has a thermal conductivity of 1.4 W / m-K or more and 5 W / m-K or less.

5. The noise filter according to any one of claims 1 to 3, wherein the thermally conductive portion is configured to deform so as to be in close contact with the external member when the thermally conductive portion is compressed by a compression load when the thermally conductive portion is sandwiched between the magnetic core and the external member and / or between the molded portion and the external member in use of the noise filter. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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