Noise filter

Abstract

To reduce common mode noise and normal mode noise.SOLUTION: A device includes at least one first core positioned between multiple wiring lines and formed by laminating a first thin plate made of a magnetic material, and at least one second core formed by laminating a second thin plate made of a magnetic material, the second core is joined to both ends of the first core so as to surround the multiple wiring lines together with the first core, and the joining surface between the first core and the second core is magnetically conductive but electrically insulated, thereby further reducing common mode noise and normal mode noise.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to noise filters. [Background technology]

[0002] Conventionally, a noise filter of this type has been proposed that includes an annular core surrounding two wires (first and second bus bars) made of a magnetic material (see, for example, Patent Document 1). In this filter, a core made of a magnetic material different from the annular core is disposed between the two wires. This is said to be able to suppress interference of both common mode and normal mode noise with the two wires. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-519222 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the inventors have found that the above-mentioned noise filter may not be able to sufficiently reduce both modes of noise generated in the two wirings, and therefore a noise filter that can further reduce both modes of noise is desired.

[0005] The noise filter of the present disclosure has a primary purpose of further reducing common mode noise and normal mode noise. [Means for solving the problem]

[0006] The noise filter of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] The first noise filter of the present disclosure comprises: A noise filter that suppresses noise generated from a plurality of wirings, at least one first core positioned between the plurality of wirings and formed by laminating first thin plates made of a magnetic material; at least one second core formed by laminating second thin plates made of a magnetic material; Equipped with the second core is joined to both ends of the first core so as to surround the plurality of wirings together with the first core, The joint surface between the first core and the second core is magnetically conductive and electrically insulated. The gist of this is as follows.

[0008] A first noise filter of the present disclosure includes at least one first core positioned between a plurality of wirings and formed by laminating first thin plates made of a magnetic material, and at least one second core formed by laminating second thin plates made of a magnetic material, the second core being joined to both ends of the first core so as to surround the plurality of wirings together with the first core, and the joining surfaces between the first core and the second core being magnetically conductive but electrically insulated. The inventors have discovered that this noise filter has a relatively high impedance to common-mode noise and normal-mode noise. By having a high impedance to common-mode noise and normal-mode noise, the noise filter can further reduce common-mode noise and normal-mode noise.

[0009] The second noise filter of the present disclosure comprises: A noise filter that suppresses noise generated from a plurality of wirings, at least one first core positioned between the plurality of wirings and formed by laminating first thin plates made of a magnetic material; at least one second core formed by laminating second thin plates made of a magnetic material; Equipped with the second core is joined to both ends of the first core so as to surround the plurality of wirings together with the first core, The stacking direction of the first and second thin plates is parallel to the wiring. or The lamination direction of the second thin plates is the parallel running direction, the first thin plates are laminated in a direction approximately perpendicular to the lamination direction of the second thin plates, and the second core is not divided at the joint with the first core. or The stacking direction of the first thin plates is the parallel running direction, and the second thin plates are stacked in a direction approximately perpendicular to the stacking direction of the first thin plates, and are divided at the joint. The gist of this is as follows.

[0010] A first noise filter of the present disclosure includes at least one first core positioned between a plurality of wirings and formed by laminating first thin plates made of a magnetic material, and at least one second core formed by laminating second thin plates made of a magnetic material, the second core being joined to both ends of the first core so as to surround the plurality of wirings together with the first core, the lamination direction of the first and second thin plates being parallel to the wirings, or the lamination direction of the second thin plate being parallel to the wirings and the first thin plate being laminated in a direction approximately perpendicular to the lamination direction of the second thin plate, the second core being undivided at the joint with the first core, or the lamination direction of the first thin plate being parallel to the wirings and the second thin plate being laminated in a direction approximately perpendicular to the lamination direction of the first thin plate, and the second core being divided at the joint. The inventors have found that this noise filter has relatively high impedance to common-mode noise and normal-mode noise. The noise filter has a high impedance to common mode noise and normal mode noise, thereby being able to further reduce common mode noise and normal mode noise. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing an outline of the configuration of a noise filter 20 of the present embodiment. [Figure 2] 10 is an explanatory diagram illustrating examples of bonding states A to D between the first core 22 and the second core 24 and combinations 1 to 4 of the lamination directions of the first and second thin plates 220, 240. FIG. [Figure 3] FIG. 10 is an explanatory diagram showing an example of impedance for common mode noise and normal mode noise of a noise filter formed by forming the shapes of the first and second cores 22, 24 to be bonded in states A to D and combining the lamination directions of the first and second thin plates 220, 240 to be 1 to 4. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a diagram showing an outline of the configuration of a noise filter 20 of this embodiment. The noise filter 20 is fixed to a device around two wires 10 using a fixture (not shown), and includes a first core 22 and a second core 24. Examples of the wires 10, 12 include a positive bus bar and a negative bus bar used as the positive and negative lines of a power line for an inverter or a battery.

[0013] The first core 22 is located between the wiring 10 and the wiring 12. The first core 22 is formed so that the lamination direction of the first thin plate 220 formed of a magnetic material is the first direction (the direction in which the wirings 10 and 12 extend), which is the parallel direction running parallel to the wirings 10 and 12. Examples of the first thin plate 220 include an electromagnetic steel plate, a thin plate formed of a cobalt (Co)-based amorphous alloy material, or a nanocrystalline material. The first core 22 has both end portions 22a and 22b in the first direction and in the second direction, which is the thickness direction of the wirings 10 and 12 and is substantially perpendicular to the first direction, tapered toward the second direction. Here, "substantially perpendicular" includes both perpendicular and a tilt that is slightly inclined from perpendicular but can be considered perpendicular.

[0014] The second core 24 is formed by stacking flat, doughnut-shaped second thin plates 240 made of a magnetic material in a first direction. Examples of the second thin plates 240 include electromagnetic steel plates, thin plates made of a cobalt (Co)-based amorphous alloy material, and nanocrystalline materials. The second thin plates 240 may be made of the same material as the first thin plates 220, or a different material. The thickness of the second thin plates 240 may be the same as or different from that of the first thin plates 220. The second core 24 is bonded to both ends 22a, 22b of the first core 22 with an adhesive having high insulating properties and magnetic permeability so as to surround the wirings 10, 12 together with the first core 22. Therefore, the joint surfaces between the first core 22 and the second core 24 are electrically insulated and magnetically conductive.

[0015] Here, an example of the relationship between the shapes of the first and second cores 22, 24, the lamination direction of the first and second thin plates 220, 240, and the impedance of the noise filter with respect to common mode noise and normal mode noise will be described. FIG. 2 is an explanatory diagram illustrating examples of combinations 1 to 4 of bonding states A to D between the first core 22 and the second core 24 and combinations 1 to 4 of the lamination direction of the first and second thin plates 220, 240. FIG. 3 is an explanatory diagram showing examples of the impedance of a noise filter with respect to common mode noise and normal mode noise, formed by combining the shapes of the first and second cores 22, 24 with bonding states A to D and the lamination directions of the first and second thin plates 220, 240 with combinations 1 to 4. FIG. 2 illustrates an enlarged view of a main portion where the first core 22 and the second core 24 are bonded (for example, main portion 30 of the noise filter 20 illustrated in FIG. 1). In FIG. 2 , in joined state A, both ends of the first core 22 are exposed in the second direction and are flush with the outer surface of the second core 24. In joined state B, both ends of the first core 22 are tapered in the second direction and are exposed and flush with the outer surface of the second core 24. In joined states A and B, the second core 24 is divided at the joint with the first core 22. In joined state C, both ends of the first core 22 are tapered in the second direction and are not exposed at the outer surface of the second core 24. In joined state D, both ends of the first core 22 are not tapered in the second direction and are not exposed at the outer surface of the second core 24. In joined states C and D, the second core 24 is not divided at the joint with the first core 22. In combination 1, the first thin plates 220 are stacked in the second direction, and the second thin plates 240 are stacked in a third direction perpendicular to the first and second directions. In combination 2, the first thin plates 220 are stacked in the first direction, and the second thin plates 240 are stacked in the second direction. In combination 3, the first thin plates 220 are stacked in the third direction, and the second thin plates 240 are stacked in the first direction. In combination 4, the first and second thin plates 220, 240 are stacked in the first direction.

[0016] The inventors have found that, as shown in Fig. 3, by setting the stacking direction of the first and second thin plates 220, 240 to Combination 4, it is possible to provide a noise filter having relatively high impedance against both common mode noise and normal mode noise, regardless of the shape of the first and second cores 22, 24 being any of bonding conditions A to D. The inventors have also found that by setting the stacking direction of the first and second thin plates 220, 240 to Combination 2 and the shape of the first and second cores 22, 24 to Bonding Condition A or B, i.e., by setting the second core 24 to be divided at the bonded portion with the first core 22, it is possible to provide a noise filter having relatively high impedance against both common mode noise and normal mode noise. Furthermore, the inventors have found that a noise filter having relatively high impedance against both common mode noise and normal mode noise can be provided by setting the stacking direction of the first and second thin plates 220, 240 to Combination 3 and setting the shapes of the first and second cores 22, 24 to Joint Condition C or D, i.e., by setting the second core 24 to a state where it is not divided at the joint with the first core 22. Based on this insight of the inventors, in the noise filter 20 of this embodiment, the stacking direction of the first and second thin plates 220, 240 to Combination 4 and the shapes of the first and second cores 22, 24 to Joint Condition C make the impedance relatively high against both common mode noise and normal mode noise.

[0017] The inventors also found that when the second core 24 is magnetically conductive but electrically insulated from the first core 22, the impedance to both common mode noise and normal mode noise is higher than when the second core 24 is magnetically isolated or electrically conductive from the first core 22. Based on this insight of the inventors, in the noise filter 20 of this embodiment, the joint surface between the first core 22 and the second core 24 is magnetically conductive but electrically insulated, thereby making the impedance relatively high to both common mode noise and normal mode noise.

[0018] In this way, in the noise filter 20 of this embodiment, the joint surface between the first core 22 and the second core 24 is magnetically conductive and electrically insulated, and the lamination direction of the first and second thin plates 220, 240 is set to the first direction, thereby making the impedance relatively high for both common mode noise and normal mode noise, thereby further reducing common mode noise and normal mode noise.

[0019] The noise filter 20 of this embodiment described above includes a first core 22 located between the wirings 10, 12 and formed by laminating first thin plates 220 made of a magnetic material, and a second core 24 formed by laminating second thin plates 240 made of a magnetic material. The second core 24 is joined to both end portions 22a, 22b of the first core 22 so as to surround the wirings 10, 12 together with the first core 22, and the joint surfaces between the first core 22 and the second core 24 are magnetically conductive and electrically insulated, thereby enabling further reduction of common mode noise and normal mode noise.

[0020] The coil is also provided with a first core 22 positioned between the wirings 10, 12 and formed by laminating a first thin plate 220 made of a magnetic material, and a second core 24 formed by laminating a second thin plate 240 made of a magnetic material, and the second core 24 is joined to both ends 22a, 22b of the first core 22 so as to surround the wirings 10, 12 together with the first core 22, and the lamination direction of the first and second thin plates 220, 240 is set to the first direction which is the direction running parallel to the wirings 10, 12, thereby further reducing common mode noise and normal mode noise.

[0021] In the noise filter 20 of this embodiment, the stacking direction of the first and second thin plates 220, 240 is the first direction, which is the direction parallel to the wirings 10, 12. However, the stacking direction of the first and second thin plates 220, 240 may be combination 2, and the shapes of the first and second cores 22, 24 may be joint condition A or B. That is, the first thin plate 220 may be stacked in the first direction (parallel direction), and the second thin plate 240 may be stacked in the second direction (direction substantially perpendicular to the stacking direction of the first thin plate 220), and the second core 24 may be divided at the joint with the first core 22. Furthermore, the stacking direction of the first and second thin plates 220, 240 may be combination 3, and the shapes of the first and second cores 22, 24 may be joint condition C or D. That is, the stacking direction of the second thin plate 240 may be the first direction (parallel direction), the first thin plate 220 may be stacked in the third direction (a direction approximately perpendicular to the stacking direction of the second thin plate 240), and the second core 24 may be in a state where it is not divided at the joint with the first core 22.

[0022] In the above-described embodiment, the first core 22 is joined to the second core 24 by adhesive, but any method may be used to join the first core 22 to the second core 24, and for example, the first core 22 may be joined to the second core 24 by crimping.

[0023] In the above-described embodiment, the noise filter 20 surrounds two wires 10 and 12. However, the noise filter 20 may surround three or more wires. Examples of three or more wires include the U-phase, V-phase, and W-phase wires of a three-phase motor. In this case, a plurality of first cores 22 may be provided, and one second core 24 may be joined to both ends of each first core 22 so as to surround the three or more wires together with the plurality of first cores 22. Furthermore, when four or more wires 10 and 12 are to be surrounded, a plurality of first and second cores 22 and 24 may be provided, and each second core 24 may be joined to both ends of the corresponding first core 22 so as to surround the respective wires together with the corresponding first core 22.

[0024] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be explained. In the embodiment, the wirings 10 and 12 correspond to the "wirings," the first thin plate 220 corresponds to the "first thin plate," the first core 22 corresponds to the "first core," the second thin plate 240 corresponds to the "second thin plate," and the second core 24 corresponds to the "second core."

[0025] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0026] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments and can, of course, be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0027] The present disclosure is applicable to the noise filter manufacturing industry and the like. [Explanation of symbols]

[0028] 10, 12 Wiring, 20 Noise filter, 22 First core, 22a, 22b End portion, 24 Second core, 24a, 24b Main body portion, 220 First thin plate, 240 Second thin plate.

Claims

1. A noise filter that suppresses noise generated from a plurality of wirings, at least one first core positioned between the plurality of wirings and formed by laminating first thin plates made of a magnetic material; at least one second core formed by stacking second thin plates made of a magnetic material; Equipped with the second core is joined to both ends of the first core so as to surround the plurality of wirings together with the first core, The joint surface between the first core and the second core is magnetically conductive and electrically insulated. Noise filter.

2. A noise filter that suppresses noise generated from a plurality of wirings, at least one first core positioned between the plurality of wirings and formed by laminating first thin plates made of a magnetic material; at least one second core formed by stacking second thin plates made of a magnetic material; Equipped with the second core is joined to both ends of the first core so as to surround the plurality of wirings together with the first core, The stacking direction of the first and second thin plates is a direction parallel to the wiring. or a lamination direction of the second thin plates is the parallel running direction, the first thin plates are laminated in a direction substantially perpendicular to the lamination direction of the second thin plates, and the second core is not divided at a joint portion with the first core; or The stacking direction of the first thin plates is the parallel running direction, and the second thin plates are stacked in a direction approximately perpendicular to the stacking direction of the first thin plates, and are divided at the joint portion. Noise filter.

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