JP2006012989A - Common mode choke coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a common mode choke coil which is capable of preventing defective characteristics caused by a signal reflection, is compact, and has a large inductance as well as an excellent high frequency characteristic. <P>SOLUTION: In the common mode choke coil 31, a winding 36 is densely wound in a single layer on the outer periphery of the cylindrical body 33 of a bobbin 32. A winding 37 is densely wound in a single layer on top of the winding 36. A winding 46 is densely wound in a single layer on the outer periphery of a cylindrical body 43 of a bobbin 42. A winding 47 is densely wound in a single layer under the winding 46. These windings mutually intensify magnetic flux when a common mode noise current flows. The windings 36, 37 perform differential transmission communications and are connected to a pair of signal wires which serve as an outgoing path for current. The windings 46, 47 perform differential transmission communications and are connected to a pair of signal wires which serve as an incoming path for current. Flanges are formed with slanted surfaces 34a, 35a, 44a, 45a, and terminals of these windings are drawn out from the cylindrical bodies 33, 43 in an adjacent state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a common mode choke coil, and more particularly to a common mode choke coil inserted into a signal line having communication and power feeding functions.

  Conventional differential transmission circuits are used for communication purposes. In differential transmission, signals in opposite phases are sent to each of the pair lines, and High / Low is determined based on which signal line has a higher potential. For example, Ethernet (registered trademark) is the most common standard for personal computer LANs, and a pulse transformer is attached to the interface. When the noise emission from the cable is large, common mode choke coils are used before and after the pulse transformer.

  The effect of using the common mode choke coil is that the signal flowing in the opposite phase to the paired wire is not affected and a limiting action is applied to the common mode noise. That is, in the differential transmission circuit, currents of the same magnitude flow through the pair wires in opposite phases, so that the magnetic flux generated by the differential signal current cancels out in the magnetic core. On the other hand, magnetic fluxes generated by noise currents passing through in phase reinforce each other in the magnetic core.

  Incidentally, a signal of 100 MHz or higher is sometimes used for differential transmission communication, and the frequency of the signal and the frequency band of noise often overlap. Therefore, a low-pass filter such as a normal mode choke coil is difficult to use because it controls the signal at the same time as controlling the noise.

  By the way, recently, a standard called IEEE 802.3af has been proposed by the Institute of Electrical and Electronic Engineers (American Institute of Electrical and Electronic Engineers). This standard is a standard for a circuit in which a power feeding circuit is attached to a conventional differential transmission circuit, and is a standard for power feeding through a signal line such as a LAN cable for transmitting and receiving signals. This standard is applied to devices such as IP telephones and wireless LAN access points connected to LAN cables. When a common mode choke coil is used as a noise countermeasure for the signal line subject to this standard, the magnetic flux generated by the power supply current is generated in a reinforce direction in the magnetic core of the common mode choke coil. Therefore, the magnetic flux density of the magnetic core is close to the saturation magnetic flux density due to the magnetic flux generated by the power supply current, the common mode inductance is lowered, and the noise countermeasure effect is reduced.

  As a measure for preventing the magnetic flux density from being increased, there is a method of increasing the cross-sectional area of the magnetic core. However, the part size increases simultaneously with the magnetic core size. Further, since the magnetic core occupies a large part material cost, the increase in the magnetic core size greatly affects the part price.

  Further, if the number of turns of the winding is reduced, the magnetic flux generated in the magnetic core is reduced and is not easily saturated. However, the inductance is reduced, and the noise countermeasure effect is reduced.

  Conventionally, as a common mode choke coil for preventing noise from entering a telephone line, the one described in Patent Document 1 is known. As shown in FIG. 13, the common mode choke coil 1 includes a magnetic core composed of two U-shaped core members 10, 11, two bobbins 2, 3, and four windings 4, 5, 6. , 7.

  The bobbins 2 and 3 are disposed so that the cylindrical body portions 2a and 3a are parallel to each other. The leg portions 10b and 11b of the core members 10 and 11 are inserted into the holes 2b and 3b of the cylindrical body portions 2a and 3a, respectively. The core members 10 and 11 form a single closed magnetic path by the tip surfaces of both leg portions 10b and 11b striking each other in the holes 2b and 3b.

  The windings 4 and 5 are bifilar wound around the cylindrical body 2 a of the bobbin 2. Similarly, the windings 6 and 7 are bifilar wound around the cylindrical body portion 3 a of the bobbin 3. The windings 4 to 7 are wound so as to reinforce magnetic fluxes in the magnetic core when in-phase current flows.

  In the common mode choke coil 1 having the above configuration, the windings 4 and 5 or the windings 6 and 7 are adjacent to only two portions in the left-right direction in FIG. The generated stray capacitance is connected in series by the number of turns. Accordingly, the stray capacitance can be reduced and the noise intrusion prevention capability in a high band can be improved.

  However, the common mode choke coil 1 described in Patent Document 1 has a so-called bifilar winding structure in which the windings 4 and 5 or the windings 6 and 7 are alternately wound around the cylindrical body portions 2a and 3a only one layer. Therefore, there is a problem that the number of turns of the windings 4 to 7 per unit length is small, and the inductance obtained is smaller than the size of the bobbins 2 and 3.

  Further, in order to obtain such a bifilar winding structure, a highly accurate winding machine is required. In the case of the common mode choke coil used in the IEEE 802.3af standard, it is necessary to match the characteristic impedance of the choke coil with the characteristic impedance of the peripheral circuit to suppress reflection at the time of signal input / output. This is because when the turbulence occurs, the characteristic impedance is shifted at that portion, resulting in a problem of signal reflection. Until now, characteristic impedance has not been a problem.

  The present inventors have found that one of the factors determining the characteristic impedance is the positional relationship between two windings. That is, the main winding portion of the coil is a cylindrical body portion of the bobbin, and it is necessary to keep a distance between the two windings at a constant distance in this cylindrical body portion. In the bifilar winding structure, in order to adjust the characteristic impedance, it is necessary to perform winding while keeping the interval between the two windings constant, and more accurate winding work is required. Further, even when the winding is wound with the winding interval kept constant, there is a problem that the characteristic impedance shifts if the line spacing is shifted during subsequent assembly work or transportation work.

In addition, the present inventors have found that the lead-out portion of the winding influences one of the factors that determine the characteristic impedance. That is, the end of the winding is pulled out from the cylindrical body part to the lead terminal along the surface of the bobbin, but when two terminals are suddenly expanded at the extraction start position, the characteristic impedance is obtained at the expanded part. Deviation occurs and affects the signal passing characteristics.
Japanese Utility Model Publication No. 4-4712

  SUMMARY OF THE INVENTION An object of the present invention is to provide a common mode choke coil which prevents a characteristic failure caused by signal reflection by improving winding positional disturbance and the positional relationship of the terminal lead portion. .

  Another object of the present invention is to provide a common mode choke coil that achieves the above object and has a small size and a large inductance. In particular, it is to provide a common mode choke coil that can be inserted into a signal line circuit to which the IEEE 802.3af standard is applied, has a small inductance, and is excellent in high frequency characteristics.

  In order to achieve the above object, a first invention is a common mode choke coil formed by winding at least two windings around a cylindrical body portion of a bobbin, and is formed on the cylindrical body portion of the bobbin and on both sides thereof. An inclined surface is formed between the flange and each winding, and each winding is densely wound in a single layer on top and bottom.

  In the common mode choke coil according to the first aspect of the invention, since the inclined surface is formed between the cylindrical body portion and the flange portion, at least two windings are densely wound with a single layer stacked vertically. In this case, the probability that the windings are misaligned is low, and even if they are misaligned, deviations in the height and direction of each winding can be suppressed. Therefore, it is possible to prevent a problem that the characteristic impedance is shifted due to the reflection of the signal due to the winding disturbance.

  According to a second aspect of the present invention, in the common mode choke coil formed by winding at least two windings around the cylindrical body of the bobbin, the bobbin has a lead terminal for fixing each end of the winding. In addition, there is a locking portion for guiding each winding from the cylindrical body portion to the lead terminal, and each winding is close to each other by the locking portion.

  In the common mode choke coil according to the second aspect of the invention, the bobbin is provided with a locking portion for guiding each winding from the cylindrical body portion to the lead terminal, and the windings are brought close to each other by the locking portion. The end of the winding is aligned. Therefore, the terminal is not suddenly expanded, and it is possible to prevent a problem that the characteristic impedance of each winding is shifted.

A third invention is a common mode choke coil inserted into a signal line having communication and power feeding functions,
(A) a first bobbin and a second bobbin having a cylindrical body,
(B) a single-layer densely wound first winding provided on the cylindrical body of the first bobbin, and a single-layer densely wound second winding provided on top of the first winding;
(C) a single-layer densely wound third winding provided on the cylindrical body of the second bobbin, and a single-layer densely wound fourth winding provided on top of the third winding;
(D) a leg portion is inserted into the hole of each cylindrical body portion of the first bobbin and the second bobbin, and a magnetic core constituting a closed magnetic path is provided.
(E) The first winding and the second winding are wound in the same direction so that magnetic fluxes generated in the magnetic core are mutually intensified when in-phase noise current flows, and the third winding The wire and the fourth winding are wound in the same direction so that magnetic fluxes generated in the magnetic core are mutually intensified when in-phase noise current flows, and the first winding and the second winding. And the third winding and the fourth winding are wound so that magnetic fluxes generated in the magnetic core when in-phase noise current flows are mutually intensified,
(F) An inclined surface is formed between the cylindrical body portions of the first and second bobbins and the flange portions formed on both sides thereof,
It is characterized by.

  In the common mode choke coil according to the third invention, each of the first to fourth windings is tightly wound in a single layer, so that the number of turns per unit length increases, and the length of the cylindrical body portion of the bobbin Even if the length is short, a large inductance can be obtained. Further, the winding portion where the first winding and the second winding, or the third winding and the fourth winding are adjacent to each other is only one place in the vertical direction. Therefore, although the stray capacitance generated in the adjacent winding portion is connected in parallel only to the winding portion, the stray capacitance is small. Therefore, a common mode choke coil suitable for the signal line circuit of the IEEE 802.3af standard can be obtained. At the same time, the operational effect of the common mode choke coil according to the first aspect of the invention is also achieved.

A fourth invention is a common mode choke coil inserted into a signal line having communication and power feeding functions,
While comprising (a) to (e) above,
(G) The first and second bobbins have lead terminals for fixing the ends of the first, second, third, and fourth windings, respectively, and from the cylindrical body portion to the lead terminals. The first winding and the second winding, and the third and fourth windings are close to each other by the locking portions;
It is characterized by.

  In the common mode choke coil according to the fourth aspect of the invention, as with the common mode choke coil according to the third aspect of the invention, even if the length of the cylindrical body portion of the bobbin is short, a large inductance is obtained and adjacent. The stray capacitance generated in the winding portion is small, and a common mode choke coil suitable for the signal line circuit of the IEEE 802.3af standard can be obtained. At the same time, the operational effect of the common mode choke coil according to the second aspect of the invention is also achieved.

  Hereinafter, embodiments of a common mode choke coil according to the present invention will be described with reference to the accompanying drawings.

  An appearance of a common mode choke coil 31 according to an embodiment of the present invention is shown in FIG. 1, a horizontal sectional view thereof is shown in FIG. 3, and an electric equivalent circuit diagram is shown in FIG. The common mode choke coil 31 includes a magnetic core 50 composed of two U-shaped core members 50a and 50b, two bobbins 32 and 42, and four windings 36, 37, 46, and 47. ing.

  The bobbins 32 and 42 have cylindrical body portions 33 and 43 and flange portions 34, 35, 44 and 45 formed on both sides of the cylindrical body portions 33 and 43, respectively. Eight terminals of a pair of lead terminals 53a, 54a and 53b, 54b and 55a, 56a and 55b and 56b are respectively implanted in the flange portions 34, 35, 44 and 45. The bobbins 32 and 42 are formed of resin or the like, and are arranged so that the cylindrical body portions 33 and 43 are parallel to each other.

  The winding 36 is tightly wound on the outer periphery of the cylindrical body 33 by a single layer. The winding 37 is overlaid on the winding 36 and is tightly wound in a single layer. The windings 36 and 37 are wound with the same number of turns in the same direction so as to reinforce magnetic fluxes when in-phase noise current flows. Similarly, the winding 46 is single-layer densely wound around the outer periphery of the cylindrical body 43. The winding 47 is tightly wound on the winding 46 in a single layer. The windings 46 and 47 are wound with the same number of turns in the same direction so as to reinforce magnetic fluxes when in-phase noise current flows. Furthermore, the windings 36 and 37 and the windings 46 and 47 are wound with the same number of turns so as to reinforce magnetic fluxes when a noise current having the same phase flows.

  Each end of the winding 36 is electrically connected to the lead terminals 53a and 53b, and each end of the winding 37 is electrically connected to the lead terminals 54a and 54b. Similarly, the terminals of the winding 46 are electrically connected to the lead terminals 55a and 55b, respectively, and the terminals of the winding 47 are electrically connected to the lead terminals 56a and 56b, respectively.

  The core members 50a and 50b constituting the magnetic core 50 have arm portions 51a and 51b, and leg portions 52a and 52b extending from both ends of the arm portions 51a and 51b in a right angle direction, respectively. Yes. The leg portions 52a and 52b of the core members 50a and 50b are inserted into the holes 33a and 43a of the cylindrical body portions 33 and 43, respectively. In the core members 50a and 50b, the front end surfaces of both leg portions 52a and 52b collide with each other in the holes 33a and 43a to form one closed magnetic circuit.

  As the material of the core members 50a and 50b, Mn—Zn-based or Ni—Zn-based ferrite, or both are used. Since Mn—Zn-based ferrite has high magnetic permeability, a large inductance (several hundred μH to several mH) can be obtained as compared with Ni—Zn-based ferrite.

  Incidentally, in order to suppress the noise voltage from the low frequency band (several hundred kHz), an inductance of several hundred μH to several mH is required. On the other hand, since Ni—Zn ferrite has excellent frequency characteristics of magnetic permeability, large inductance characteristics can be obtained at a higher frequency (several tens to several hundreds of MHz) than Mn—Zn ferrite. In addition, there is a configuration in which a large inductance can be obtained in a wide frequency band by using both Mn—Zn and Ni—Zn ferrites.

  Further, a U-shaped stopper (not shown) is fitted to bring the abutting surfaces of the core members 50a and 50b into close contact. Note that the core members 50a and 50b may be firmly adhered using an adhesive instead of the stopper. Each component 32, 42, 50a, 50b is fixed by a fixing jig (not shown), or a minimum amount of adhesive or varnish (not shown) is attached to the bobbins 32, 42 and the core members 50a, 50b. It is applied and fixed between.

  In the common mode choke coil 31 having the above configuration, the windings 36, 37, 46, and 47 are each tightly wound in a single layer, so that the number of turns per unit length increases and the cylindrical shape of the bobbins 32 and 42 is obtained. Even if the lengths of the trunk portions 33 and 43 are short, a large inductance can be obtained. Further, the winding portions adjacent to the windings 36 and 37 or the windings 46 and 47 are only one portion in the vertical direction in FIG. Therefore, stray capacitance generated in adjacent winding portions can be suppressed. As a result, a 4-terminal common mode choke coil having excellent noise removal performance in a high frequency band can be obtained.

  Here, in the IEEE 802.3af standard, noise removal from the low frequency region to the high frequency region is necessary, and the component forming the waveform of the communication signal is also overlapped with the frequency band that needs noise countermeasures. Requires large inductance, low leakage inductance, and high frequency characteristics. Further, even if the noise terminal voltage regulation in the low frequency region (30 MHz or less) is applied to the communication line, the common mode choke coil 31 is suitable for removing noise from the low frequency region to the high frequency region, It has a removal effect for both noise terminal voltage in the low frequency region (30 MHz or less) and radiation noise in the high frequency region (30 MHz or more). Therefore, it can be said that the common mode choke coil 31 is a choke coil suitable for the standard of IEEE802.3af.

  FIG. 5 shows a circuit in which the common mode choke coil 31 is connected to signal lines 71 to 74 to which the IEEE 802.3af standard is applied for the purpose of providing both communication and power feeding functions. For example, the signal lines 71 to 74 are obtained by superimposing a power supply current on a LAN cable that transmits and receives signals. In FIG. 5, 61A and 61B are pulse transformers on the LAN switch side, 62 is a power supply, 65 and 66 are connectors (standard RJ-45), 68 is a load, and 69A and 69B are pulse transformers on the data terminal side.

  Next, the function and effect of the common mode choke coil 31 will be described with reference to the schematic diagram shown in FIG. In the differential transmission communication, differential signal currents of the same magnitude and opposite phase flow through the two pairs of windings 36 and 37 and 46 and 47, respectively. Therefore, the magnetic flux φ1 in the magnetic core 50 that is generated when a signal current flows through one of the pair of windings 36 and 37 is a magnetic flux that is generated when a signal current flows through the other winding 37. Although it is the same size as the magnetic flux φ1 in the body core 50, it is generated in the opposite direction. Therefore, both magnetic fluxes φ1 and φ1 cancel each other. The same applies to the pair of windings 46 and 47.

  The phenomenon of canceling out the magnetic flux occurs independently in each pair of windings 36 and 37 and 46 and 47. Accordingly, even when two different differential signal currents are simultaneously transmitted by two pairs of windings 36 and 37 and windings 46 and 47, they cannot interfere with each other in the magnetic core 50 due to magnetic coupling. Absent.

  Further, the windings 36 and 37 are combined (connected in parallel) to be used as a forward line for power supply current, and the windings 46 and 47 are combined (connected in parallel) to be used as a return line for power supply current. In this case, the sum of the power supply currents energizing the windings 36 and 37 and the sum of the power supply currents energizing the windings 46 and 47 are equal in magnitude and opposite in phase. Therefore, the magnetic flux φ2 generated in the magnetic core 50 by the windings 36 and 37 and the magnetic flux φ2 generated in the magnetic core 50 by the windings 46 and 47 cancel each other. As a result, even if the magnetic core 50 is not magnetically saturated and is a small magnetic core 50, the number of turns of the windings 36, 37, 46, and 47 can be increased to increase the inductance.

  Thus, the performance as a common mode choke coil can be sufficiently exhibited. Further, by combining the windings 36 and 37 and combining the windings 46 and 47, the allowable current that can be passed through the line is increased.

  On the other hand, in the common mode choke coil 31, when a common mode (in-phase) noise current Ic flows through the windings 36, 37, 46, and 47, the windings 36, 37, 46, and 47 enter the magnetic core 50, respectively. Magnetic flux φc is generated in the same direction. The magnetic flux φc circulates while strengthening the inside of the magnetic core 50. As a result, the impedance with respect to the common mode noise current Ic increases, and the common mode noise current Ic is suppressed. Incidentally, it is assumed that the common mode noise current Ic is about several mA at the peak and the power supply current is about several hundred mA.

  Here, two countermeasures for preventing deviations in characteristic impedance due to signal reflection will be described. Here, the bobbin 32 and the windings 36 and 37 will be described, but the same description is valid for the other bobbin 42 and the windings 46 and 47.

  First, as a first countermeasure, as shown in FIG. 2, inclined surfaces 34 a and 35 a having an angle θ are provided between the cylindrical body portion 33 of the bobbin 32 and the flange portions 34 and 35. The angle θ is preferably 120 °. Thus, when the windings 36 and 37 are aligned and wound, the probability that each of the windings 36 and 37 is displaced is low, and even if the windings 36 and 37 are displaced, the height and direction deviation can be suppressed to be small.

  This point will be described with reference to FIG. 7 and in comparison with FIG. 8 in which the flange portions 34 and 35 stand upright with respect to the cylindrical body portion 33. FIGS. 7A and 8A show an ideal state when the winding width dimension of the cylindrical body portion 33 coincides with (winding diameter × number of turns). FIG. 7B and FIG. 8B show the winding disorder state when the first layer winding 36 is wound from the left to the right and then the second layer winding 37 is wound in the return path. ing. 7B and 8B, when the winding diameter is slightly larger than the design value, or the winding state of the first layer winding 36 is slightly shifted to the right from the ideal state. Shows the case.

  As shown in FIG. 8, when the flanges 34 and 35 stand upright as in the prior art, the range of the winding diameter in which the windings 36 of the first layer can be aligned and wound is D + D / (2 X number of turns). However, in practice, even if the winding diameter range is D to D + D / (2 × number of turns), the winding start of the winding 37 of the second layer is not complete, so that the winding state is not good. It becomes stable, it shifts forward in the winding direction with a slight momentum, and then it is wound in a stable state. In that case, the final turn of the winding 37 on the second layer surface becomes the height of the third layer, and winding disturbance occurs (see FIG. 8B).

  On the other hand, as shown in FIG. 7, when the inclined surfaces 34a and 35a are provided, the case where the winding diameter is larger than the design value or winding disturbance occurs will be considered. In this case, as shown in FIG. 7B, the second-layer winding 37 is stacked on the last turn of the first-layer winding 36, and the second-layer winding 37 is not applied from the second-layer second turn. Complete loading starts. However, as in FIG. 7A, if the winding is shifted forward in a slight amount and then wound in a stable state, the final turn of the second winding 37 is the second layer. It fits in the height of the winding 37. In addition, the winding height does not reach the third layer unless the winding diameter becomes D + D / number of turns or more. Compared with the conventional example of FIG. 8, the deviation of the winding diameter is allowed up to twice.

  Here, the angle θ of the inclined surfaces 34a and 35a will be considered. When the angle θ starts to be larger than 90 °, the ride height on the third layer of the final turn of the winding 37 on the two-layer surface due to the winding jump starts to gradually decrease. As shown in FIG. 9A, when the angle θ is 120 °, the difference in winding space width between the first-layer winding 36 and the second-layer winding 37 is one turn. Even if one winding jump occurs in the winding 37, the winding 37 can be surely accommodated within the height of the second layer.

  In addition, when the angle θ is set to 120 ° or more, the ride height to the third layer when two winding jumps occur can be gradually reduced, but the thickness of the split portions 34 and 35 is set to be large. It becomes necessary to do.

  According to the experiments by the present inventors, as shown in FIG. 9B, when the angle θ is 100 ° or less, the final turn of the winding 37 of the second layer is run up to the third layer. It becomes easy. Further, as shown in FIGS. 9C and 9D, when the angle θ is 140 ° or more, the windings 36 and 37 do not face each other. Therefore, the angle θ is preferably 100 ° or more and 140 ° or less.

  As a second countermeasure, as shown in FIGS. 2, 10, and 11, the ends 36a, 36b, 37a, 37b of the windings 36, 37 are brought close to each other, so that the bobbin 32 has a cylindrical body 33. Locking portions for guiding the terminals 36a, 36b, 37a, 37b to the lead terminals 53a, 53b, 54a, 54b were provided. Specifically, the engaging portion is a groove 38b surrounded by the convex portions 38a and 38a (see FIG. 10) or a protrusion 39 (see FIG. 11).

  By guiding the ends 36a, 36b, 37a, 37b of the windings 36, 37 to the lead terminals 53a, 53b, 54a, 54b with the grooves 38b or the projections 39, the terminals 36a, 37a and the terminals 36b, 37b are respectively lead. The positional relationship close to the terminals 53a, 53b, 54a, and 54b is maintained, and the frequency region having a constant characteristic impedance can be expanded to the high frequency region. In addition, the interval between the groove portions 38b and the position of the protrusion 39 can be appropriately set for adjusting the characteristic impedance.

  In common mode choke coils, by expanding the region of constant characteristic impedance to the high frequency region, the pass characteristics of higher-order signal harmonic components are improved, and the waveform is restored as much as possible without impairing the noise countermeasure effect. Can be passed. FIG. 12A shows a state where the characteristic impedance is expanded to the high frequency region. The common mode choke coil whose characteristics were measured was manufactured in the numerical size shown in FIG.

  FIG. 12B shows the characteristic impedance of a comparative example in which such a countermeasure is not taken for reference. As is clear from FIG. 12B, in the comparative example, the impedance starts to decrease from 200 MHz. However, as is clear from FIG. 12A, such a decrease is not observed in the example of the present invention.

  The common mode choke coil according to the present invention is not limited to the above embodiment, and can be variously modified within the scope of the gist thereof.

  For example, a bobbin having a gear structure that is divided into two or more as a bobbin may be used as a magnetic core using a monolithic monolithic core or a monolithic monolithic core.

  Further, the common mode choke coil according to the present invention can be applied not only to the four lines shown in the above embodiment, but also to six lines, eight lines, or other lines. Furthermore, it can also be configured to be built in a connector (modular jack) for cable connection.

One Example of the common mode choke coil which concerns on this invention is shown, (A) is a top view, (B) is the front view. The bobbin which comprises the said common mode choke coil is shown, (A) is a top view, (B) is the front view. It is a horizontal sectional view of the common mode choke coil. It is an electrical equivalent circuit diagram of the common mode choke coil. 3 is a block diagram showing a circuit in which the common mode choke coil is connected to a signal line to which IEEE802.3af is applied. It is explanatory drawing of the effect of the said common mode choke coil. It is sectional drawing which shows the winding state (example of this invention) to the cylindrical trunk | drum of the said bobbin. It is sectional drawing which shows the winding state (conventional example) to the cylindrical trunk | drum of a bobbin. It is sectional drawing which shows the winding state according to the various inclination angles of the collar part of the said bobbin. It is a top view which shows the 1st example of the drawing-out state of a coil | winding terminal. It is a top view which shows the 2nd example of the drawing-out state of a coil | winding terminal. The impedance characteristic of a common mode choke coil is shown, (A) is an example of the present invention, and (B) is a comparative example. It is a horizontal sectional view showing a conventional common mode choke coil.

Explanation of symbols

31 ... Common mode choke coil 32, 42 ... Bobbin 33, 43 ... Cylindrical body part 34, 35, 44, 45 ... Gutter 34a, 35a ... Inclined surface 36, 37, 46, 47 ... Winding 36a, 36b, 37a , 37b ... terminal 38b ... groove 39 ... projection 50 ... magnetic core 52a, 52b ... leg

Claims (8)

In a common mode choke coil in which at least two windings are wound around a cylindrical body of a bobbin,
An inclined surface is formed between the cylindrical body portion of the bobbin and the flanges formed on both sides thereof, and each winding is closely wound in a single layer on top and bottom,
A common mode choke coil.   The common mode choke coil according to claim 1, wherein the inclined surface has an inclination angle of 120 ° ± 20 °. In a common mode choke coil in which at least two windings are wound around a cylindrical body of a bobbin,
The bobbin has a lead terminal for fixing each end of the winding, and has a locking portion for guiding the winding from the cylindrical body portion to the lead terminal. Being close to each other by the locking part,
A common mode choke coil.   The common mode choke coil according to claim 3, wherein the locking portion is a groove or a protrusion formed in the bobbin. In a common mode choke coil in which at least two windings are wound around a cylindrical body of a bobbin,
An inclined surface is formed between the cylindrical body portion of the bobbin and the flanges formed on both sides thereof, and each winding is closely wound in a single layer on top and bottom,
The bobbin has a lead terminal for fixing each end of the winding, and has a locking portion for guiding the winding from the cylindrical body portion to the lead terminal. Being close to each other by the locking part,
A common mode choke coil. A common mode choke coil inserted into a signal line having communication and power supply functions,
A first bobbin and a second bobbin having a cylindrical body,
A single-layer densely wound first winding provided on the cylindrical body of the first bobbin, and a single-layer densely wound second winding provided on the first winding;
A single-layer densely wound third winding provided on the cylindrical body of the second bobbin, and a single-layer closely wound fourth winding provided on top of the third winding;
A leg portion is inserted into a hole in each cylindrical body portion of the first bobbin and the second bobbin, and a magnetic core that forms a closed magnetic path is provided.
The first winding and the second winding are wound in the same direction so that magnetic fluxes generated in the magnetic core are mutually intensified when in-phase noise current flows, and the third winding The winding and the fourth winding are wound in the same direction so that magnetic fluxes generated in the magnetic core when in-phase noise current flows are mutually intensified, and the first winding and The second winding, the third winding, and the fourth winding are wound such that magnetic fluxes generated in the magnetic core are mutually intensified when a noise current of the same phase flows.
An inclined surface is formed between the cylindrical body portions of the first and second bobbins and the flange portions formed on both sides thereof;
A common mode choke coil. A common mode choke coil inserted into a signal line having communication and power supply functions,
A first bobbin and a second bobbin having a cylindrical body,
A single-layer densely wound first winding provided on the cylindrical body of the first bobbin, and a single-layer densely wound second winding provided on the first winding;
A single-layer densely wound third winding provided on the cylindrical body of the second bobbin, and a single-layer closely wound fourth winding provided on top of the third winding;
A leg portion is inserted into a hole in each cylindrical body portion of the first bobbin and the second bobbin, and a magnetic core that forms a closed magnetic path is provided.
The first winding and the second winding are wound in the same direction so that magnetic fluxes generated in the magnetic core are mutually intensified when in-phase noise current flows, and the third winding The winding and the fourth winding are wound in the same direction so that magnetic fluxes generated in the magnetic core when in-phase noise current flows are mutually intensified, and the first winding and The second winding, the third winding, and the fourth winding are wound such that magnetic fluxes generated in the magnetic core are mutually intensified when a noise current of the same phase flows.
The first and second bobbins have lead terminals for fixing the ends of the first, second, third, and fourth windings, respectively, and are wound from the cylindrical body to the lead terminals. The first winding and the second winding and the third winding and the fourth winding are close to each other by the locking portion;
A common mode choke coil. A common mode choke coil inserted into a signal line having communication and power feeding functions,
A first bobbin and a second bobbin having a cylindrical body,
A single-layer densely wound first winding provided on the cylindrical body of the first bobbin, and a single-layer densely wound second winding provided on the first winding;
A single-layer densely wound third winding provided on the cylindrical body of the second bobbin, and a single-layer closely wound fourth winding provided on top of the third winding;
A leg portion is inserted into a hole in each cylindrical body portion of the first bobbin and the second bobbin, and a magnetic core that forms a closed magnetic path is provided.
The first winding and the second winding are wound in the same direction so that magnetic fluxes generated in the magnetic core are mutually intensified when in-phase noise current flows, and the third winding The winding and the fourth winding are wound in the same direction so that magnetic fluxes generated in the magnetic core when in-phase noise current flows are mutually intensified, and the first winding and The second winding, the third winding, and the fourth winding are wound such that magnetic fluxes generated in the magnetic core are mutually intensified when a noise current of the same phase flows.
An inclined surface is formed between the cylindrical body portions of the first and second bobbins and the flange portions formed on both sides thereof,
The first and second bobbins have lead terminals for fixing the ends of the first, second, third, and fourth windings, respectively, and are wound from the cylindrical body to the lead terminals. The first winding and the second winding and the third winding and the fourth winding are close to each other by the locking portion;
A common mode choke coil.

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