JP6419508B2 - Noise absorber - Google Patents

Description

  The present invention relates to an apparatus for absorbing noise contained in a signal transmitted through a cable, and more particularly to a noise absorbing apparatus suitable for application to a flat cable.

  As a noise absorbing device applied to a flat cable, there is one having a configuration in which a flat cable is sandwiched between a pair of flat magnetic bodies (ferrite cores). For example, in Patent Document 1, a pair of magnetic bodies (ferrite cores) each having an L-shaped cross-section are combined so as to face each other so that the flat cable is sandwiched therebetween, thereby surrounding the flat cable with a magnetic body. A technique for configuring a closed magnetic circuit has been proposed. Patent Document 2 is a configuration in which the first and second magnetic bodies having the main surface portion are combined so as to face one side and the other side of the flat cable, respectively, and one of the magnetic bodies is one form. Protruding walls are provided at both ends of the U-shaped, and when the other flat magnetic body is disposed facing each other, the main surface portion and the protruding wall surround the flat cable.

  The noise absorbing devices of Patent Documents 1 and 2 have the advantage that they can be applied to flat cables having different thickness dimensions because of the dimensional freedom of the opposing spacing of the magnetic bodies forming a pair. However, in the technique of Patent Document 1, the pair of combined magnetic bodies has a configuration in which the end surfaces on both sides are in contact with each other on a flat surface, and therefore both magnetic bodies may move relative to each other due to slippage on the contact surfaces. . That is, a relative movement in which one magnetic body is moved with respect to the other magnetism occurs, and if such a relative movement occurs, the closed magnetic path by both magnetic bodies may be damaged, and the noise absorption effect is reduced.

  In Patent Document 2, by forming one magnetic body in a U shape, both end surfaces of both magnetic bodies are brought into contact with different surfaces, and both magnetic bodies prevent relative movement in the rotational direction on the plane. Is possible. However, this technique cannot prevent relative movement of the other magnetic body in the extending direction of the protruding wall provided on one magnetic body. Further, in this technique, it is necessary to prepare magnetic bodies having different shapes as a pair of magnetic bodies, and the number of parts increases.

JP 2000-173828 A JP-A-5-159936 JP 2008-10792 A

  In order to prevent such relative movement of the magnetic body, Patent Documents 1 and 2 separately provide fixing parts for fixing both magnetic bodies and preventing relative movement, but this increases the number of parts. In addition, the external dimensions of the noise absorbing device increase due to the fixed parts. Patent Document 3 proposes a configuration in which both magnetic bodies are held by an adhesive tape, which is effective in minimizing the increase in the external dimensions of the noise absorbing device. When this decreases, the effectiveness of fixing both magnetic materials decreases.

  An object of the present invention is to provide a noise absorbing device that prevents relative movement in a pair of magnetic bodies and secures a closed magnetic path surrounding a cable to enhance the noise absorbing effect.

The present invention is a noise absorbing device that absorbs noise by sandwiching a cable with a pair of magnetic bodies, and each of the magnetic bodies includes a main surface portion disposed with the cable interposed therebetween, and a unidirectional portion of the main surface portion . some areas of the respective end faces of the both end portions, protruding from the respective end faces in the one direction, and to have a projecting walls paired protruded toward the side for holding the cable.

Further, when both the magnetic bodies hold the cable, the respective projecting walls of the respective magnetic bodies have their end faces in a direction orthogonal to the one direction abutting against the opposing end faces of the opposing magnetic body projecting walls. In addition, the inner surface in one direction of each protruding wall is configured to abut on the end surface of the main surface portion of the counterpart magnetic body.

  According to the present invention, even if the thicknesses of the cables sandwiched between the two magnetic bodies are different because the projecting walls provided on the pair of magnetic bodies are in contact with the main surface portion or the projecting wall of the opposite magnetic body, A closed magnetic circuit surrounding the cable is secured, and a suitable noise absorbing effect is obtained. In addition, the projecting wall provided on the magnetic body abuts against the projecting wall of the counterpart magnetic body, and more preferably abuts on the main surface portion of the counterpart magnetic body, thereby preventing the relative movement of the both magnetic bodies and the cable using the both magnetic bodies. A closed magnetic circuit is secured, and a suitable noise absorption effect is obtained.

The external appearance perspective view of the ferrite core of the noise absorber of this invention. The external appearance perspective view of the state attached to the flat cable. (A) Sectional drawing of the width direction of the state of FIG. 2, (b) BB sectional drawing of Fig.3 (a). The external appearance perspective view of a different mounting form. Furthermore, the external appearance perspective view of a different mounting form. The disassembled perspective view of the noise absorber containing a holding case. The perspective view of the state which inserted the ferrite core in the holding case. The external appearance perspective view of the state attached to the flat cable.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external perspective view of a magnetic body, ie, a ferrite core, which is a main component of the noise absorber of the present invention. The pair of ferrite cores 1 are formed in the same shape, and a noise absorbing device is configured by combining the pair of ferrite cores 1 as will be described later.

  The ferrite core 1 has a main surface portion 11 having a rectangular flat plate shape having a long side longer than the width of the flat cable FC to be applied and a short side having a required size. Here, in order to make the following explanation easy to understand, the length direction is the same as the length direction of the flat cable FC among the long side direction and the short side direction of the main surface portion 11, and the width direction of the flat cable FC. The same direction as is referred to as the width direction. At both ends in the width direction of the main surface portion 11, projecting walls 12 projecting at a required height in the same plate thickness direction are integrally formed. As a result, the ferrite core 1 is formed with a pair of projecting walls 12 at both ends in the width direction, so that the noise absorbing device comprising the pair of ferrite cores 1 is provided with two pairs of projecting walls 12. Become.

  The protruding wall 12 is formed so as to protrude outward in the width direction from the end surfaces 11 a at both ends in the width direction of the main surface portion 11. Further, the protruding wall 12 is formed so that the lengthwise dimension thereof is approximately ½ of the lengthwise dimension of the main surface portion 11, and the protruding walls 12 at both ends of the protruding wall 12 are the main surface portion. 11 are formed in regions opposite to each other in the length direction so as to be staggered across a center line C that bisects 11 in the length direction. In other words, the protruding walls 12 at both ends are formed symmetrically with respect to the center point of the main surface portion 11.

  Here, in the main surface portion 11 and the protruding wall 12 of each ferrite core 1, when the ferrite core 1 is mounted on the flat cable FC, a surface facing the flat cable FC is defined as an inner surface. The surface on the opposite side is referred to as the outer surface.

  Furthermore, in this embodiment, on the outer surface of the main surface portion 11 of the ferrite core 1, engagement concave portions 13 are formed at two positions with a required interval in the width direction at both end portions in the length direction. Since the engaging recess 13 is used when the holding case 2 described later is applied, it may not be provided in this embodiment.

  In the noise absorbing device comprising a pair of ferrite cores, as shown in FIG. 2, the inner surface of the main surface portion 11 of one ferrite core 1 is placed on the lower side of the flat cable FC, and the other ferrite core 1 The inner surface of the main surface portion 11 is directed downward and is covered on the upper side of the flat cable FC, and the two ferrite cores 1 are combined with each other. In this state, the flat cable FC is sandwiched between the main surface portions 11 of both ferrite cores 1 in the thickness direction and sandwiched between the protruding walls 12 in the width direction. At this time, each protruding wall 12 of each ferrite core 1 is positioned in a portion where the protruding walls 12 at both ends in the width direction of the counterpart ferrite core 1 do not exist.

  Thus, in a state where the pair of ferrite cores 1 are combined, as shown in FIG. 3A, a cross-sectional view in the width direction, and in FIG. Among the end faces in the length direction, the end face 12a on the side along the center line C of the main surface portion 11 is brought into contact with the similar end face 12a of the protruding wall 12 of the counterpart ferrite core 1. At the same time, the inner surface of each projecting wall 12 is in contact with or close to the end surface 11 a in the width direction of the main surface portion 11 of the counterpart ferrite core 1. Thereby, the projecting wall 12 of each ferrite core 1 is abutted against at least the projecting wall 12 of the counterpart ferrite core 1 and is assembled in an endless manner surrounding the entire periphery of the flat cable FC by both ferrite cores 1.

  As a result, a closed magnetic circuit surrounding the flat cable FC is formed by the two ferrite cores 1, and a noise absorbing effect for the flat cable FC is exhibited. At this time, the interval between the inner surfaces of the main surface portions 11 of the ferrite cores 1 is changed in the plate thickness direction due to the difference in the thickness dimension of the flat cable FC. Since the protrusion protrudes at a height, the protruding wall 12 is in contact with the protruding wall 12 of the counterpart ferrite core 1 or the end face 11a of the main surface portion 11 of the counterpart ferrite core 1 within the range of the protruding height. Therefore, the closed magnetic circuit by both ferrite cores 1 is also secured, and the noise absorption effect is not lowered.

  Furthermore, in this embodiment, as shown in FIG. 4, an adhesive tape T having a required shape is attached to each ferrite core 1 on the outer surface of the main surface portion 11. The pressure-sensitive adhesive tape T is formed of a belt-like single-sided pressure-sensitive adhesive tape having substantially the same width as the length of the main surface portion 11 and longer than the width of the main surface portion 11. Then, the main surface portion 11 is adhered to the outer surface of the main surface portion 11 in one side region in the width direction of the outer surface of the main surface portion 11, and the front surface side region is indicated by a chain line with a protective paper (not shown) left. It is comprised as the surplus part Ta extended in the width direction.

  In this embodiment, after the two ferrite cores 1 are combined as described above, the surplus portion Ta of the adhesive tape T is changed to the main wall of the projecting wall 12 and the counterpart ferrite core 1 as shown by the arrow in FIG. The two ferrite cores 1 are fixed to each other by the adhesive tape T by turning to each outer surface of the surface portion 11 and then peeling off the protective paper to adhere. Therefore, the relative movement of both ferrite cores 1 is prevented by the adhesive tape T, and a closed magnetic path by both ferrite cores 1 is also ensured.

  In this embodiment, when the adhesive tape T is damaged or the fixed state of the two ferrite cores 1 is lowered due to deterioration due to aging, etc., one ferrite core 1 becomes the counterpart ferrite core 1. The relative movement in the width direction is prevented by the contact between the inner surface of the protruding wall 12 of one ferrite core 1 and the end surface 11a of the main surface portion 11 of the other ferrite core 1 even if the relative movement in the width direction is attempted. Is done. In addition, even if both ferrite cores 1 are about to move in the length direction, the length direction between the end surface 12a of the protruding wall 12 of one ferrite core 1 and the end surface 12a of the protruding wall 12 of the other ferrite core 1 is increased. Movement in the length direction is prevented by the contact.

  Further, even if one ferrite core 1 is relatively rotated along the surface direction of the main surface portion 11, the clockwise relative rotation of FIG. 2 or FIG. The rotation is prevented by contact with the end surface 11 a of the main surface portion 11 of the other ferrite core 1. 2 or 4, the relative rotation is prevented by contact between the projecting walls 12 of one ferrite core 1 and the end faces 12 a of the projecting walls 12 of the other ferrite core 1. The

  Thus, when the pair of ferrite cores 1 are combined so as to sandwich the flat cable FC, the pair of protruding walls 12 provided at both ends of each ferrite core 1, that is, two pairs of protrusions as a noise absorbing device. When the wall 12 abuts against the main surface portion 11 and the projecting wall 12 of the opposite ferrite core 1, relative movement of both the ferrite cores 1 is prevented, and a closed magnetic circuit composed of these ferrite cores 11 is maintained. This is maintained even when a large external force is applied between the two ferrite cores 1 or when the adhesive force of the adhesive tape T is deteriorated and the two ferrite cores 1 are not sufficiently fixed by the adhesive tape T. . Therefore, a noise absorbing device having a high noise absorbing effect can be obtained.

  In addition, due to tolerances produced when the ferrite core 1 is manufactured, the projecting walls 12 at both ends of the main surface portions 11 are simultaneously contacted with the end surfaces 11 a of the main surface portion 11 of the counterpart ferrite core 1 when both the ferrite cores 1 are assembled. Even in such a case, it is conceivable that even in such a case, by adjusting the relative positions of the two ferrite cores 1 as appropriate, at least one of the protruding walls 12 is one end face of the main surface portion 11 of the counterpart ferrite core 1. It is possible to maintain the state of contact with 11a. Regardless of such tolerances, each projecting wall 12 of both ferrite cores 1 is reliably brought into contact with the projecting wall 12 of the counterpart ferrite core 1 at the end face 12a, so that it is possible to maintain a closed magnetic circuit. .

  Here, as shown in FIG. 5, the shape of the adhesive tape T is changed, and in particular, a second surplus portion Tb extending in the length direction from the region adhered to the outer surface of the ferrite core 1 is formed, and this second surplus is formed. The flat cable FC can be fixed to the ferrite core 1 by sticking the portion Tb to the surface of the flat cable FC. Since this can be performed on each adhesive tape T of both ferrite cores 1, it can be firmly fixed on both sides of the flat cable FC. In this example, a configuration is shown in which one adhesive tape T adhered to the upper ferrite core 1 is adhered to the upper surface of the flat cable FC, and at the same time, the excess portion Ta adheres to the lower ferrite core 1.

  Although not shown, if the second surplus portion Tb in FIG. 5 is formed to have a width dimension larger than the width dimension of the ferrite core 1, the second surplus portion Tb is adhered to the flat cable FC and at the same time both widths. It is also possible to adhere to the substrate or chassis on which the noise absorbing device is disposed, and to fix the noise absorbing device to the substrate or chassis.

  The noise absorbing device of the present invention may be fixed to the flat cable, the substrate, the chassis, or the like using a holding case instead of the adhesive tape described in the above embodiment. FIG. 6 is an external view of the holding case 2 and includes a pair of case portions 21a and 21b integrally formed by resin molding. Each case portion 21a, 21b is formed in a rectangular container shape with one side opened so that the ferrite core 1 can be accommodated, and both case portions 21 are bendable hinge pieces provided on the respective end surfaces in the width direction. 22 are connected. A locking claw 23 is formed on the opposite end surface of the one case portion 21a, and a locking frame piece 24 is formed on the opposite end surface of the other case portion 21b. As a result, the hinge piece 22 is bent and the case portions 21a and 21b are opposed to each other, and the locking frame piece 24 is engaged with the locking claw 23, whereby the case portions 21a and 21b The storage chamber of the core 1 is configured.

  Each of the case portions 21a and 21b has substantially the same structure except for the locking claw 23 and the locking frame piece 24 described above. In the following, both case portions 21a and 21b are collectively referred to by reference numeral 21, and the same reference numerals are given to equivalent parts of both case portions 21a and 21b. Both end surfaces in the length direction of the case portion 21 are recessed except for both end regions in the width direction of the case portion, and the flat cable FC (not shown) can be inserted in the length direction into the recessed regions. Has been. In addition, in the recessed area, hook pieces 25 are formed inwardly at two locations with a predetermined interval in the width direction. These hook pieces 25 correspond to the engaging recesses 13 provided in the ferrite core 1, and four hook pieces 25 are formed in each case portion 21.

  Core pressing pieces 26 are formed on the bottom surface of each case portion 21 at two locations facing each other in the width direction. These core pressing pieces 26 are cut and raised in a U shape while being inclined toward the inside of the case portion 21. Each of the core pressing pieces 26 exerts an elastic force when deformed in the outer surface direction of the case portion 21. Has been.

  Further, one end face of the end faces in the length direction of the case portions 21 is formed with a cable holding piece 27 protruding in the recessed area. The cable holding piece 27 is formed as a cantilever piece whose tip is inclined from a position close to the bottom surface of the case part 21 toward the opened side of the case part 21.

  In this holding case, as shown in FIG. 7, the ferrite core 1 is housed in each case portion 21 so that the fixed state of the ferrite core 1 can be held and at the same time the ferrite core 1 can be protected from external force. . When the ferrite core 1 is housed in the case portion 21, when the ferrite core 1 is inserted from the opening of the case portion 21, the ferrite core 1 is inserted while spreading the hook piece 25 outward. When inserted, the hook piece 25 is elastically restored inward and engaged with the engaging recess 13 of the ferrite core 1, thereby preventing the ferrite core 1 from falling off the case portion 21. Further, in this state, the outer surface of the ferrite core 1 is in contact with the core pressing piece 26 and elastically deforms the core pressing piece 26 toward the outside, so that the ferrite core 1 is deformed by the elastic restoring force of the core pressing piece 26. It is urged toward the opening of the case portion 21. This urging force is effective in maintaining the engagement state between the hook piece 25 and the engagement recess 13.

  Then, as shown in FIG. 8, the hinge piece 22 is bent so that the flat cable FC is sandwiched between the two case portions 21a and 21b, the two case portions 21a and 21b are opposed, and the locking frame piece 24 is placed. 23 is engaged with the locking claws, the case portions 21a and 21b are brought into contact with each other to hold the flat cable FC. At the same time, the ferrite core 1 built in each case portion 21a, 21b is in a state of sandwiching the flat cable FC. In this state, as described above, the projecting walls 12 at both ends of each ferrite core 1 are brought into contact with the projecting wall 12 or the main surface portion 11 of the other ferrite core 1 to constitute a closed magnetic circuit.

  Further, in this state, the cable holding pieces 27 of the case portion 21 are brought into contact with both surfaces of the flat cable FC, and the flat cable FC is held by the elastic force of the cable holding pieces 27. Thereby, the noise absorbing device can be fixed to the flat cable FC.

  By attaching the ferrite core 1 to the flat cable FC using the holding case 2, the relative position of both ferrite cores 1 can be stably held, and the closed magnetic circuit constituted by both ferrite cores 1 can be securely held, and the flat Noise absorption effect for cable FC can be secured. Further, by using the holding case 2, it is possible to prevent the ferrite core 1 from being damaged by an external force. Furthermore, the mounting position of the ferrite core 1 with respect to the flat cable FC can be stably held by using the holding case 2.

  Here, by appropriately adjusting the shape or size of the hook piece 25 provided in the case portion 21, when the ferrite core 1 is internally supported by the case portion 21, the gap between the engagement recess 13 and the hook piece 25 is increased. A displacement force may be generated. For example, the ferrite core 1 that is internally provided by forming two hook pieces 25 on one end surface side in the length direction of the case portion 21 to be larger than the two hook pieces 25 on the other end surface side is long in the case portion 21. It can be urged in the vertical direction. Therefore, by urging the ferrite core 1 in the length direction in at least one case portion 21, the ferrite core 1 is engaged with the other ferrite core when the case portions 21a and 21b are engaged. 1 is relatively moved in the length direction, and the end surfaces in the length direction of the respective projecting walls 12 can be reliably brought into contact with each other. Thereby, the closed magnetic circuit by the ferrite core 1 is ensured.

  In addition, when fixing a holding case to a board | substrate or a chassis, it can implement | achieve by using the adapter which fits and supports a holding case although it does not illustrate by fixing with a double-sided tape.

  The noise absorbing device of the present invention is a closed magnetic circuit constituted by the ferrite core 1 by appropriately designing the shape of the paired ferrite cores 1, particularly the height of the protruding walls 12 forming the pairs of both the ferrite cores 1. The opposing distance dimension of the main surface part 11 of both the ferrite cores 1 can be adjusted, ensuring a path | route. That is, the distance between the inner surfaces of the main surface portions 11 of both ferrite cores 1 can be adjusted to a range of 0 to approximately twice the height of the protruding wall 12. Therefore, even when the thickness dimension of the cable inserted between the ferrite cores 1 is different, the noise absorption for the cable functions effectively as long as it is within the adjustable distance dimension. In this case, the present invention is also effective for a cable in which a plurality of cables are bundled in a flat shape, and is not necessarily limited to being applied to the flat cable described in the embodiment.

  In the embodiment, an example in which one protruding wall is provided at each end of one ferrite core has been described. However, in the case of a ferrite core having a large lengthwise dimension, two or more at each end are provided. It is also possible to form projecting walls, that is, to form three or more pairs of projecting walls.

  The present invention can be applied to a noise absorbing device that absorbs noise by holding a cable with a pair of magnetic bodies.

1 Ferrite core (magnetic material)
2 Holding case 11 Main surface portion 12 Projecting wall 13 Engaging recess 21 (21a, 21b) Case portion 22 Hinge 23 Locking claw 24 Locking frame piece 25 Hook piece 26 Core pressing piece 27 Cable clamping piece FC Flat cable (cable)

Claims (1)

A noise absorbing device that absorbs noise by sandwiching a cable with a pair of magnetic bodies, wherein each of the magnetic bodies includes a main surface portion that is disposed with the cable interposed therebetween, and each of both end portions in one direction of the main surface portion. When a part of the end surface has a pair of projecting walls projecting in one direction from the respective end surfaces and projecting toward the side that sandwiches the cable , and both magnetic bodies sandwich the cable In addition, each projecting wall of each magnetic body has an end surface in a direction orthogonal to the one direction abutting against an opposing end surface of the projecting wall of the counterpart magnetic body, and an inner surface in one direction of each projecting wall is the counterpart. A noise absorbing device, characterized in that it is configured to abut against the end surface of the main surface portion of the magnetic body .

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