Magnetic sheet and magnetic sheet structure provided with same

Abstract

The invention provides a magnetic sheet and a magnetic sheet structure having the same. The magnetic sheet (1) includes a magnetic plate (10) having a size capable of being continuously wound around the outer periphery of the cable (2) for at least one circle, a protective layer (20) provided on the surface of the magnetic plate (10), and an adhesive layer (30) provided on the surface of the magnetic plate (10) on the opposite side from the protective layer (20), the protective layer (20) and the adhesive layer (30) having a larger size than the magnetic plate (10). When the adhesive layer (30) faces the cable (2) and the magnetic sheet (1) is wound around the outer periphery of the cable (2), the protective layer (20) and the adhesive layer (30) can be wound such that a part of the adhesive layer (30) adheres to the surface of the protective layer (20) on the opposite side from the magnetic sheet (10).

Description

Technical Field

[0001] The present invention relates to a magnetic sheet for winding around the outer periphery of an object and a magnetic sheet structure using the magnetic sheet. Background Art

[0002] In recent years, in electric vehicles and hybrid vehicles, the current supplied to the cables mounted on the vehicle body has been gradually increasing, and on the other hand, the electromagnetic wave noise generated by the cables has become a serious problem. Electromagnetic noise can interfere with other electronic devices, causing malfunctions and failures, etc., so as the demand for autonomous driving expands, it has become a growing concern. Therefore, measures to suppress electromagnetic noise are required. As such a measure, a magnetic sheet made of a sheet-like magnetic material is wound and fixed around an object such as a cable that is a source of electromagnetic noise to suppress the electromagnetic noise.

[0003] As a method of fixing such a magnetic sheet to an object, for example, Patent Document 1 discloses a method of fixing a magnetic sheet to an object using rivets or a cloth tape. Specifically, in Patent Document 1, a strip-shaped shielding material made of a magnetic body is overlapped and wound around an object in a spiral shape, and then the overlapping portion is fastened with rivets or fixed from the outside of the shielding material with a cloth tape. Thereby, the magnetic sheet can be wound around the object in a good state.

[0004] In addition, Patent Document 2 discloses a method of winding a single-sided adhesive sheet with a pair of ferrite sintered bodies attached thereto around an object and fixing it to the object by overlapping one end of the adhesive sheet on the other end side (see FIG. 5 of Patent Document 2). Prior Art Documents Patent Documents Patent Document 1: Japanese Patent Application Laid-Open No. H09-214166 Patent Document 2: Japanese Patent Application Laid-Open No. 2009-212419 Summary of the Invention -Problems to be Solved by the Invention-

[0006] In the case of the method of fixing using additional components such as rivets or a cloth tape in Patent Document 1, as described above, the magnetic sheet can be wound around the object in a relatively good state. However, in the method of Patent Document 1, after winding the magnetic sheet, additional components are required for fixing, resulting in an increase in the number of working steps and a decrease in productivity. In addition, in the case of fixing with a cloth tape or the like, the magnetic sheet may peel off from the object due to insufficient adhesion, resulting in a reduction in the suppression effect of electromagnetic wave noise.

[0007] In addition, as described in Patent Document 2, according to the method of overlapping and fixing the adhesive surface at one end of the single-sided adhesive sheet on the other end side, the operability can be improved without additional components. However, in the method of Patent Document 2, in the state where the magnetic sheet is wound around a flat cable as an object, the pair of ferrite sintered bodies can only be disposed on the front side and the back side of the flat cable respectively, that is, in a state of being sandwiched between the front side and the back side. Therefore, electromagnetic noise may leak from the portion where the ferrite sintered body is not disposed, and a good noise suppression effect of the magnetic sheet cannot be ensured.

[0008] The present invention has been completed in view of the above problems, and an object thereof is to make the operability of winding the magnetic sheet around an object easy, continuously exert a noise suppression effect on the outer periphery of the object, and suppress a decrease in the noise suppression effect caused by peeling of the magnetic sheet from the object after the magnetic sheet is wound around the object. -Means for Solving the Problem-

[0009] In order to achieve the above object, the magnetic sheet of the present invention has the following structure: the magnetic plate has a size capable of continuously winding around the outer periphery of the object at least once, and it is difficult for the magnetic sheet to peel off from the object after the magnetic sheet is wound around the object.

[0010] Specifically, the magnetic sheet according to the present invention is a magnetic sheet for winding around the outer periphery of an object, and is characterized in that the magnetic sheet includes: a magnetic plate having a size capable of continuously winding around the outer periphery of the object at least once; a protective layer having a size larger than that of the magnetic plate and covering the surface of the magnetic plate; and an adhesive layer having a size larger than that of the magnetic plate and provided on the surface of the magnetic plate opposite to the protective layer; when the adhesive layer faces the object side and the magnetic sheet is wound around the outer periphery of the object, the protective layer and the adhesive layer are formed so as to be wound such that a part of the adhesive layer adheres to the surface of the protective layer opposite to the magnetic plate.

[0011] According to the magnetic sheet of the present invention, the magnetic sheet can be directly attached to an object via an adhesive layer provided on a magnetic plate. Therefore, additional components such as a cloth belt for fixing are not required, and thus the winding operability of the magnetic sheet on the object can be improved. In addition, in the magnetic sheet of the present invention, the magnetic plate has a size capable of continuously winding around the outer periphery of the object at least once. Therefore, when the adhesive layer faces the object side and the magnetic sheet is wound around the outer periphery of the object, the outer periphery of the object can be covered once by the magnetic plate. As a result, it is difficult for electromagnetic noise to leak from the object, and thus a good noise suppression effect of the magnetic sheet can be ensured. Furthermore, when the magnetic sheet is wound around the outer periphery of the object, the protective layer and the adhesive layer can be wound such that a part of the adhesive layer adheres to the surface of the protective layer on the side opposite to the magnetic plate. Therefore, after the magnetic plate and the protective layer are wound around the outer periphery of the object at least once, the protective layer is further wound around the outer peripheral surface of the object via the adhesive layer. As a result, the magnetic sheet can be reliably fixed to the outer periphery of the object, and the reduction in the noise suppression effect caused by the magnetic sheet peeling off from the object after the magnetic sheet is wound on the object can be suppressed. Therefore, according to the magnetic sheet of the present invention, the winding operability of the magnetic sheet on the object can be made easy, and the reduction in the noise suppression effect caused by the magnetic sheet peeling off from the object or the like can be suppressed.

[0012] In the magnetic sheet of the present invention, preferably, in the winding direction of the magnetic sheet, the region including the magnetic plate is disposed between regions not including the magnetic plate. When the adhesive layer faces the object side and the magnetic sheet is wound around the outer periphery of the object, one of the regions not including the magnetic plate has a size capable of continuously winding around the outer periphery of the region including the magnetic plate at least once.

[0013] As a result, after the magnetic plate and the protective layer are continuously wound around the outer periphery of the object at least once via the adhesive layer, the protective layer is further continuously wound around the outer peripheral surface of the object at least once via the adhesive layer, so that the magnetic sheet can be more firmly fixed to the object.

[0014] The magnetic sheet of the present invention can be a magnetic sheet formed in a strip shape.

[0015] In addition, another object of the present invention is a magnetic sheet structure, which includes an object and any one of the above magnetic sheets. The magnetic sheet is wound around the outer periphery of the object such that the adhesive layer faces the object side, and a part of the adhesive layer adheres to the surface of the protective layer on the side opposite to the magnetic plate.

[0016] Such a magnetic sheet structure includes the magnetic sheet described in the present invention above. Therefore, it can facilitate the operation of winding the magnetic sheet around an object, and can cover the outer periphery of the object with a magnetic plate for one full turn. Furthermore, it can prevent the magnetic sheet from peeling off the object after the magnetic sheet is wound around the object, thus ensuring a good noise suppression effect. - Effects of the Invention -

[0017] According to the magnetic sheet of the present invention, the operation of winding the magnetic sheet around an object can be facilitated, the noise suppression effect can be continuously exerted on the outer periphery of the object, and the reduction of the noise suppression effect caused by the magnetic sheet peeling off the object after the magnetic sheet is wound around the object can be suppressed. Description of the Drawings

[0018] Figure 1 is a top view of the magnetic sheet of an embodiment of the present invention. Figure 2 is the magnetic sheet of an embodiment of the present invention at Figure 1 a cross-sectional view taken along line II-II. Figure 3 is a perspective view showing the usage state of the magnetic sheet of an embodiment of the present invention. Figure 4 is showing the usage state of the magnetic sheet of an embodiment of the present invention at Figure 3 a cross-sectional view taken along line IV-IV. Detailed Embodiments

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description of the preferred embodiments is essentially only an example and is not intended to limit the present invention, the application method of the present invention, or the use of the present invention.

[0020] First, with reference to Figure 1 and Figure 2 a magnetic sheet 1 according to an embodiment of the present invention will be described. Figure 1 is a top view of the magnetic sheet 1, Figure 2 is Figure 1 a cross-sectional view taken along line II-II. As shown in Figure 1 and Figure 2As shown, the magnetic sheet 1 according to this embodiment includes a magnetic plate 10, a protective layer 20 provided on the surface of the magnetic plate 10, and an adhesive layer 30 provided on the surface of the magnetic plate 10 on the side opposite to the protective layer 20. As will be described later, the magnetic plate 10 has a size such that when the magnetic sheet 1 is wound around an object, it can be continuously wound around the outer periphery of the object for at least one week. The protective layer 20 and the adhesive layer 30 have a size larger than that of the magnetic plate 10. In particular, as will be described later, the protective layer 20 and the adhesive layer 30 are formed such that when the magnetic sheet 1 is wound around an object, a part of the adhesive layer 30 adheres to the surface of the protective layer 20 on the side opposite to the magnetic plate 10. In addition, since the protective layer 20 and the adhesive layer 30 have a size larger than that of the magnetic plate 10, the magnetic sheet 1 has a structure in which in its longitudinal direction, the region 1a including the magnetic plate 10 is sandwiched between the regions 1b and 1c that do not include the magnetic plate 10. Preferably, one region 1b that does not include the magnetic plate 10 is shorter than the other region 1c, and the length of the region 1c is greater than or equal to the length of the region 1a including the magnetic plate 10. In addition, the length of the magnetic plate 10 (region 1a including the magnetic plate 10) of the magnetic sheet 1 is the length that can be continuously wound around the outer periphery of the object for at least one week as described above. It should be noted that in Figure 1 , the shape of the magnetic sheet 1 is shown as a strip, but it is not limited thereto, and it may also be a fan shape or a trapezoid. In addition, the width and thickness of the magnetic sheet 1 are not particularly limited, and the length is also not particularly limited as long as the above conditions are satisfied, and can be appropriately adjusted according to the outer diameter of the object, the size of the winding range, etc.

[0021] The magnetic plate 10 is a magnetic plate obtained by forming a sintered body made of a magnetic material or a molded body obtained by mixing magnetic material powder and resin into a plate shape. The type of magnetic material used is not particularly limited as long as it has magnetic properties. For example, spinel ferrites such as Ni-Zn ferrite and Mn-Zn ferrite, hexagonal ferrites such as Ba ferrite, and soft magnetic metals such as iron or iron-based alloys can be used. The manufacturing method of the magnetic plate 10 is also not particularly limited. As long as it is a sintered body made of a magnetic material, for example, a method of forming a ferrite forming sheet by coating a ferrite dispersion coating on a plastic film and then firing to obtain a ferrite sintered body can be adopted.

[0022] When using a ferrite sintered body as the magnetic plate 10, in order to facilitate winding the magnetic sheet 1 around an object, the ferrite sintered body can be pre-divided into small pieces in the magnetic sheet 1. In order to divide the ferrite sintered body into small pieces, predetermined dividing grooves can also be formed at the stage of the ferrite formed sheet. The dividing grooves can be continuous or discontinuous, and multiple minute recesses can also be formed instead of the dividing grooves. The magnetic plate 10 is divided into triangles, quadrilaterals, polygons of any size or a combined shape thereof through the pre-formed dividing grooves. In addition, it can also be divided into an irregular shape without forming the dividing grooves.

[0023] As the material of the protective layer 20, there is no particular limitation as long as it is a resin that can stretch and not break when the magnetic sheet 1 is wound around an object. For example, resin materials such as polyethylene terephthalate (PET) can be used. The protective layer 20 can be adhered to the magnetic plate 10 through an adhesive material (not shown) such as double-sided tape. In addition, the protective layer 20 itself can also be a resin tape containing an adhesive material.

[0024] The adhesive layer 30 has no particular limitation as long as it can adhere the magnetic plate 10 to an object. For example, double-sided tape having adhesive materials provided on both sides of a resin substrate such as PET can be used. As the substrate, in addition to PET, polyimide, polyurethane resin, acrylic resin, paper, silicon, vinyl chloride resin, etc. can also be used. As the adhesive material, acrylic-based, chemical-resistant adhesive materials, heat-resistant adhesive materials, hot melt adhesives, etc. can be used.

[0025] Next, with reference to Figure 3 and Figure 4 , a more detailed description of the magnetic sheet 1 according to an embodiment of the present invention will be given. Figure 3 is a perspective view showing a state where the magnetic sheet 1 is wound around a cable 2 as an object, Figure 4 is Figure 3 a cross-sectional view taken along line IV-IV in Figure 3 and Figure 4As shown, the magnetic sheet 1 is wound around the outer periphery of the cable 2 with the adhesive layer 30 facing the cable 2 side. Specifically, first, the region 1b with a smaller length in the region of the magnetic sheet 1 without the magnetic plate 10 is attached to the cable 2, and starting from this point, the magnetic sheet 1 is wound around the outer periphery of the cable 2. Thus, the region 1c without the magnetic plate 10 overlaps and is wound around the outer periphery of the region 1a containing the magnetic plate 10. It should be noted that in this embodiment, the object is represented by three cables 2, but the number and outer diameter of the cables 2 are not particularly limited. In addition, the method of winding the magnetic sheet 1 around the outer periphery of the cable 2 is not particularly limited either. For example, the magnetic sheet 1 can be continuously wound in a spiral along the axial direction of the cable 2. In addition, as described above, since the region 1b of the magnetic sheet 1 without the magnetic plate 10 is the starting point when winding the magnetic sheet 1 around the cable 2, the length of this region 1b is preferably 1 / 6 to 1 / 5 of the outer periphery of the cable 2. In particular, in this embodiment, the length of the region 1b is 1 / 6 to 1 / 5 of the length of the magnetic plate 10.

[0026] As Figure 3 and Figure 4 shown, when the magnetic sheet 1 is wound around the outer periphery of the cable 2, as described above, since the magnetic plate 10 has a size that can be continuously wound around the outer periphery of the object for at least one week, the magnetic plate 10 and the protective layer 20 are continuously wound around the outer periphery of the cable 2 for one week via the adhesive layer 30. Thereby, it is difficult for electromagnetic noise to leak from the cable 2, and thus the electromagnetic noise generated by the cable 2 can be effectively suppressed. Furthermore, a part of the adhesive layer 30 is wound in such a way as to adhere to the surface of the protective layer 20 on the side opposite to the magnetic plate 10. Specifically, in the state where the magnetic plate 10 and the protective layer 20 are wound around the outer periphery of the cable 2, a part of the protective layer 20 (the region 1c without the magnetic plate 10) is further wound around the outer peripheral surface of the cable 2 via the adhesive layer 30. Thereby, the magnetic sheet 1 can be reliably fixed to the outer periphery of the cable 2, and thus the reduction of the noise suppression effect caused by the magnetic sheet 1 peeling off from the cable 2 after the magnetic sheet 1 is wound around the cable 2 can be suppressed. In order to more effectively prevent this peeling, it is preferable to set the region 1c without the magnetic plate 10 to have a length that can be wound around the outer periphery of the magnetic plate 10 (the region 1a containing the magnetic plate 10) for more than one week. It should be noted that in this embodiment, the magnetic plate 10 is wound around the outer periphery of the cable 2 for one week, but this is not limited thereto, as long as it is continuously wound around the outer periphery of the cable 2 for at least one week or more. In addition, since the protective layer 20 is provided to cover the surface of the magnetic plate 10, damage to the magnetic plate 10 caused by contact between the magnetic sheet 1 and surrounding components can be prevented. In addition, when using a ferrite sintered body as the magnetic plate 10 as described above, by providing the protective layer 20 to cover the surface of the magnetic plate 10, it is possible to prevent small pieces of the ferrite sintered body from falling off from the protective layer 20, and it is also possible to prevent damage to surrounding components caused by the hard ferrite sintered body being exposed from the protective layer 20.

[0027] As described above, according to the magnetic sheet 1 according to the present embodiment, as described above, the magnetic plate 10 has a size capable of continuously winding around the outer periphery of the object at least once. Therefore, the magnetic plate 10 can be continuously wound around the outer periphery of the cable 2 once, thereby ensuring a good noise suppression effect. Further, after the magnetic plate 10 is wound around the outer periphery of the cable 2 at least once, a part of the protective layer 20 (the area 1c excluding the magnetic plate 10) is wound via the adhesive layer 30. Therefore, the magnetic sheet 1 can be reliably fixed to the outer periphery of the cable 2. Thus, after the magnetic sheet 1 is wound around the cable 2, it is possible to suppress the case where the magnetic sheet 1 peels off from the cable 2 and the noise suppression effect is reduced. Therefore, according to the magnetic sheet 1 according to the present embodiment, the operability of winding the magnetic sheet 1 around the cable 2 can be made easy, the noise suppression effect can be continuously exerted on the outer periphery of the object, and the reduction of the noise suppression effect caused by the peeling of the magnetic sheet 1 from the cable 2 can be suppressed.

[0028] Another embodiment of the present invention is a magnetic sheet structure including an object and the above magnetic sheet. The magnetic sheet is wound around the outer periphery of the object such that the adhesive layer faces the object side, and a part of the adhesive layer is adhered to the surface of the protective layer on the side opposite to the magnetic plate. As described above, the outer periphery of the object can be covered with the magnetic plate once, and further, after the magnetic sheet is wound around the object, it is possible to prevent the magnetic sheet from peeling off from the object, thereby ensuring a good noise suppression effect.

[0029] In the present embodiment, a cable is exemplified as the object, but the present invention is not limited thereto. For example, it can also be applied to electronic devices such as RFID and non-contact power supply devices. -Symbol Explanation-

[0030] 1: Magnetic sheet 2: Cable 10: Magnetic plate 20: Protective layer 30: Adhesive layer

Claims

1. A magnetic sheet, which is a magnetic sheet for winding around the outer periphery of an object, wherein, The magnetic sheet includes: A magnetic plate having a size capable of continuously winding around the outer periphery of the object for at least one week; A protective layer having a size larger than that of the magnetic plate and disposed to cover the surface of the magnetic plate; and An adhesive layer having a size larger than that of the magnetic plate and disposed on the surface of the magnetic plate opposite to the protective layer; When the adhesive layer faces the object side and the magnetic sheet is wound around the outer periphery of the object, the protective layer and the adhesive layer are formed so that a part of the adhesive layer can be wound and adhered to the surface of the protective layer opposite to the magnetic plate.

2. The magnetic sheet according to claim 1, wherein, In the winding direction of the magnetic sheet, the region including the magnetic plate is disposed between regions not including the magnetic plate, When the adhesive layer faces the object side and the magnetic sheet is wound around the outer periphery of the object, one of the regions not including the magnetic plate has a size capable of continuously winding around the outer periphery of the region including the magnetic plate for at least one week.

3. The magnetic sheet according to claim 1 or 2, wherein, The magnetic sheet is formed in a strip shape.

4. A magnetic sheet structure, wherein, The magnetic sheet structure includes an object and the magnetic sheet according to claim 1 or 2, The magnetic sheet is wound around the outer periphery of the object such that the adhesive layer faces the object side and a part of the adhesive layer is adhered to the surface of the protective layer opposite to the magnetic plate.

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