JPH0686306U - Wideband common mode noise reduction coil - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a common mode noise reduction coil capable of ensuring high impedance over a wide band. [Constitution] Winding conductors 5 and 6 are attached to a hollow bobbin 3 with a flange.
Are simultaneously wound a certain number of times, and the spacer 7 made of an insulating material is fitted on the upper layer. Furthermore, after the previous winding conductors 5 and 6 are continuously wound on it, the respective ends are connected to the terminal metal fittings, and for each of the winding conductors 5 and 6, the previously wound part and the later part are connected. The feature is that the stray capacitance generated between the wound portions is reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a structure of a broadband common mode noise reduction coil for reducing induction noise of a communication line.

[0002]

[Prior art]

 In terminal equipment such as telephones and facsimiles that are connected to the lead-in wire of a communication line or home wiring, electromagnetic waves of medium- and short-wave radio waves and high-frequency equipment are coupled to generate interference voltage (common mode noise) between the signal line and the ground. May occur, which may cause communication failure or may cause equipment malfunction. In order to attenuate these disturbing voltages, it is effective to insert a choke coil in the communication line to reduce the induced current flowing into the equipment. At this time, in order to improve the reduction effect, it is necessary to increase the impedance of the choke coil.

[0003]

[Problems to be solved by the device]

 It is necessary to realize a high-impedance coil over a wide band in order to improve the noise reduction effect on medium- and short-wave broadcast waves and various electromagnetic waves. A toroidal core has been proposed as one of this type of coils. For example, in the case of a ferrite core with an outer diameter of 14 mm, an inner diameter of 8 mm and a width of 6 mm, it is necessary to wind around 60 turns depending on the ferrite permeability. . Since the inner diameter is small, automation is difficult and there is a problem in terms of economy. In addition, when wound on a hollow bobbin with a flange, the floating capacitance between the windings lowers the impedance in the high frequency range, which impairs wide bandwidth.

An object of the present invention is to provide a wide band common mode noise reduction coil that can more easily secure a high impedance over a wide band in a choke coil composed of an EI type or EE type ferrite core. is there. In other words, it is characterized by achieving high impedance from low frequencies to high frequencies without increasing stray capacitance between windings.

[0005]

[Means for Solving the Problems]

 The broadband common mode noise reduction coil according to the present invention comprises a conductor coil in which a conductor wire is wound many times around a hollow bobbin with a flange, and a magnetic circuit that passes through the hollow portion of the hollow bobbin and extends at least once outside the conductor coil. In a common mode coil having a ferrite core configured to be closed, an insulating material spacer inserted in an intermediate layer of the lap winding of the conductor coil is provided.

[0006]

[Action]

 In the present invention, since the spacer of the insulating material is inserted in the intermediate layer of the lap winding, the stray capacitance generated between the part wound before the winding and the part wound after the winding is reduced, and The decrease in coil impedance is reduced.

[0007]

【Example】

 FIG. 1 is a sectional view of an embodiment of the present invention. FIG. 2 is a development view of the constituent members of FIG. However, the conductor wire is omitted in FIG. Also, in FIG. 1, the terminal hardware provided on the bobbin is not shown.

1 and 2 show a two-wire common mode noise reduction coil composed of an EI ferrite core. Reference numeral 1 is an E-type ferrite core, 2 is an I-type ferrite core, 3 is a central bobbin made of an insulator, and an upper portion 3a and a lower portion 3b each having a hole through which an iron core 1a at the center of the E-type ferrite core 1 are formed are It is configured so as to be integrally connected by the hollow portion 3c. Reference numeral 4 is a terminal metal piece, 5 and 6 are winding conductors, 5a, 5b, 6a and 6b are end portions, and 7 is a horseshoe-shaped spacer made of an insulating material. As the insulating material, for example, polymer resin such as fluorine resin or nylon is used, and the thickness is preferably 0.5 mm or more.

Next, the winding will be described. Two winding conductors 5 and 6 are simultaneously wound on a hollow bobbin 3 with a flange a fixed number of times, and a horseshoe-shaped spacer 7 made of an insulating material is fitted on the upper layer thereof. Further, the above winding conductors 5 and 6 are further wound thereon, and the respective end portions 5a, 5b, 6a and 6b are connected to the terminal metal fitting 4. In this way, the spacer 7 made of an insulating material is inserted in the middle layer of the lap winding.

The central iron core 1a of the E-shaped ferrite core 1 is penetrated from above into the hollow bobbin 3 in which the winding is finished, and the I-shaped ferrite core 2 is abutted from the opposite side and integrally held by a case not shown. Then, the wideband common mode noise reduction coil is completed.

FIG. 3 is an equivalent circuit diagram of the coil of the present invention. The previously wound portion corresponds to the section A, and the portion wound after the insulating material spacer 7 is inserted corresponds to the section B. It is well known that each conductor coil is represented as a parallel circuit of an inductance and a stray capacitance, but since section A and section B are arranged via a spacer 7 of insulating material, The stray capacitance generated between the two can be suppressed to a small level, so that the impedance drop at high frequencies can be prevented.

In the above embodiment, the case where the insulating material spacer 7 is inserted in the middle of the winding at one position has been described. However, if a plurality of spacers 7 are inserted in the middle of the winding, the impedance characteristic is further improved. Will be done. Similarly, the two-wire winding conductors 5 and 6 have been described, but the same configuration can be applied to multi-pair wires such as four wires and six wires, and the impedance characteristic improvement in the common mode can be expected. Although the EI type core has been described as the ferrite core shape, any ferrite core may be used so long as the magnetic circuit is closed at least once outside the conductor coil, and the same effect can be obtained even with an EE type core. Can be expected.

[0013]

[Effect of device]

 As described above, according to the present invention, the hollow bobbin with the flange is wound around the conductor coil many times, and the magnetic circuit is closed by passing through the hollow portion of the hollow bobbin at least once outside the coil. In a common mode coil with a configured ferrite core, a spacer of insulating material inserted in the middle layer of the winding of the conductor coil is provided, so when winding multiple times on a hollow bobbin, winding in the middle By inserting a spacer and then applying the remaining winding on top of it, the stray capacitance between the beginning and end of the winding can be kept low, so the characteristics of the conductor coil in the high frequency range can be reduced. There is an advantage that the reduction can be prevented with a simple configuration.

[Brief description of drawings]

FIG. 1 is a sectional front view of a conductor coil portion showing an embodiment of the present invention.

FIG. 2 is a developed view of the constituent members of FIG.

FIG. 3 is an electrical equivalent circuit diagram of the embodiment shown in FIG.

[Explanation of symbols]

 1 E-type ferrite core 2 I-type ferrite core 3 Hollow bobbin for winding 4 Terminal hardware 5 Winding conductor 6 Winding conductor 7 Insulating spacer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Nobuo Kuwahara, 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Takemi Arita, 1-3, Gotenyama, Musashino-shi, Tokyo NTT Advanced Technology Co., Ltd. Inside the company

Claims (1)

[Scope of utility model registration request] 1. A conductor coil having a winding bobbin wound around a flanged hollow bobbin a number of times, and a magnetic circuit is closed by passing through a hollow portion of the hollow bobbin at least once outside the conductor coil. A common mode noise reduction coil, comprising: a common mode coil having a ferrite core; and a spacer made of an insulating material inserted in an intermediate layer of a lap winding of the conductor coil.