Abstract:
A coil-included terminal block allowing for a noise suppression effect. The coil-included terminal block includes: a terminal attachment member to which at least three terminal pairs are attached, each of the terminal pairs including a terminal and another terminal; and a plurality of coils configured to connect the terminals of the at least three terminal pairs to the respective other terminals of the at least three terminal pairs.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of priority to Japanese Patent Application 2016-074141 filed Apr. 1, 2016, the entire content of which is incorporated herein by reference. 
       TECHNICAL FIELD 
       [0002]    The present disclosure relates to a coil-included terminal block. 
       BACKGROUND 
       [0003]    Japanese Patent Laying-Open No. 2000-286136 discloses a line filter applied to single-phase alternative current and three-phase alternating current. This line filter includes a common mode coil, an X capacitor, and a Y capacitor. The X capacitor and the Y capacitor are connected to the input side and output side of the common mode coil. A relay terminal is provided at the upper portion of the input-side or output-side capacitor, and they are sealed together in a case. The input-side and output-side capacitors are connected to each other via the common mode coil connected to the respective relay terminals. 
         [0004]    For a single-phase power supply, two coils are wound around an annular core. For a three-phase power supply, three coils are wound around an annular core. 
       SUMMARY 
       [0005]    The line filter disclosed in Japanese Patent Laying-Open No. 2000-286136 can reduce noise in two or three power supply lines. In this line filter, the input-side and output-side capacitors having the relay terminals at the upper portions are sealed in the case together. The common mode coils are connected to the relay terminals. When mounting this line filter on a device, it is required to secure a space for a circuit component including the plurality of capacitors at the input and output sides and the common mode coils. 
         [0006]    Depending on a position in which the circuit component included in the line filter is to be disposed, a power supply line subsequent to the line filter may need to be contained in the device. Particularly in a high frequency band, the power supply line subsequent to the line filter is affected by high-frequency noise generated in components, interconnections, or the like in the device. Hence, a sufficient noise suppression effect for the power supply line may not be obtained. 
         [0007]    The present disclosure has an object to provide a coil-included terminal block allowing for a sufficient noise suppression effect. 
         [0008]    A coil-included terminal block according to one embodiment of the present disclosure includes: 
         [0009]    a terminal attachment member to which at least three terminal pairs are attached, each of the terminal pairs including a terminal and another terminal; and 
         [0010]    a plurality of coils configured to connect the terminals of the at least three terminal pairs to the respective other terminals of the at least three terminal pairs. 
         [0011]    An external power supply cable or earth line is connected to the terminal of each of the terminal pairs of the coil-included terminal block. Since the coils are disposed inside this terminal block, leakage of harmonic noise generated in the device is blocked just before the external power supply cable. Accordingly, the leakage of the harmonic noise to the power supply cable can be suppressed effectively. Furthermore, since the coil is inserted in the earth line, the impedance of the earth line becomes high. Accordingly, leakage current flowing to the earth line can be reduced. 
         [0012]    The coil-included terminal block may further include a core, wherein the plurality of coils may be commonly wound around the core to construct a common mode choke coil. 
         [0013]    When the earth line is connected to one of the plurality of terminal pairs and the power supply lines are connected to the rest of the terminal pairs, common mode noise produced in the power supply line and the earth line can be suppressed from leaking to outside. 
         [0014]    In the coil-included terminal block, the core may have an annular shape and may have at least a portion having a flat plate-like shape, and the coils may be commonly wound around the portion having the flat plate-like shape. 
         [0015]    A relative positional relation can be substantially the same between the plurality of terminal pairs and the plurality of coils corresponding to the respective terminal pairs. Accordingly, the characteristics of the coils connected to the respective terminal pairs can be the same. 
         [0016]    In the coil-included terminal block, the at least three terminal pairs may be disposed on a surface of the terminal attachment member to orient in a same direction. 
         [0017]    Since a terminal can be accessed from one direction, workability can be improved in connecting the power supply cable or the earth line to the terminal. 
         [0018]    In the coil-included terminal block, the terminal attachment member may be provided with distinguishing marks for associating the at least three terminal pairs with a positive terminal, a negative terminal, and an earth terminal. 
         [0019]    During an operation of connecting a cable, the positive terminal, the negative terminal, and the earth terminal can be readily distinguished. 
         [0020]    The coil-included terminal block may further include a shield member covering the plurality of coils, the shield member being connected to the terminal of the terminal pair associated with the earth terminal. 
         [0021]    This makes it possible to reduce electromagnetic radiation from the coil and electromagnetic coupling between the coil and another component. 
         [0022]    According to the coil-included terminal block above, an external power supply cable or an earth line is connected to one terminal of each of the terminal pairs of the coil-included terminal block. Since the coils are disposed in this terminal block, leakage of harmonic noise generated in the device is blocked just before the external power supply cable. Accordingly, the leakage of the harmonic noise to the power supply cable can be suppressed effectively. Furthermore, since the coil is inserted in the earth line, the impedance of the earth line becomes high. Accordingly, leakage current flowing to the earth line can be reduced. 
         [0023]    The foregoing and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1A  is a perspective view of a coil-included terminal block according to a first embodiment. 
           [0025]    Each of  FIG. 1B  and  FIG. 1C  is a cross sectional view of the coil-included terminal block according to the first embodiment. 
           [0026]      FIG. 1D  is an equivalent circuit diagram of the coil-included terminal block according to the first embodiment. 
           [0027]      FIG. 2A  is a perspective view of a coil-included terminal block according to a second embodiment. 
           [0028]      FIG. 2B  is a cross sectional view of the coil-included terminal block according to a second embodiment. 
           [0029]      FIG. 2C  is an equivalent circuit diagram of the coil-included terminal block according to the second embodiment. 
           [0030]    Each of  FIG. 3A  and  FIG. 3B  is a cross sectional view of a coil-included terminal block according to a third embodiment. 
           [0031]    Each of  FIG. 4A  and  FIG. 4B  is a cross sectional view of a coil-included terminal block according to a fourth embodiment. 
           [0032]      FIG. 5  is a cross sectional view of a coil-included terminal block according to a modification of the fourth embodiment. 
           [0033]      FIG. 6  is a cross sectional view of a coil-included terminal block according to a fifth embodiment. 
           [0034]      FIG. 7  is a cross sectional view of a coil-included terminal block according to a modification of the fifth embodiment. 
       
    
    
     DETAILED DESCRIPTION 
     First Embodiment 
       [0035]    With reference to  FIG. 1A  to  FIG. 1D , the following describes a coil-included terminal block according to a first embodiment. 
         [0036]      FIG. 1A  shows a perspective view of the coil-included terminal block according to the first embodiment. Three terminal pairs  11  are attached to a hollow terminal attachment member  10  composed of an insulating material such as a resin. Three terminal pairs  11  are disposed on a surface of terminal attachment member  10  to orient in the same direction, for example, in an upward direction. An xyz orthogonal coordinate system is defined in which the height direction of terminal attachment member  10  corresponds to the z direction. 
         [0037]    Each of terminal pairs  11  includes one pair of terminals  12   a ,  12   b  arranged side by side in the y direction. Three terminal pairs  11  are arranged side by side in the x direction. Terminal attachment member  10  has partition plates  13  provided between adjacent terminal pairs  11 . Terminal attachment member  10  has a ridge-like portion  14  provided between the pair of terminals  12   a ,  12   b  of each of terminal pairs  11 . Ridge-like portion  14  extends in the x direction. Partition plates  13  and ridge-like portions  14  prevent short circuit between cable terminals connected to respective terminals  12   a ,  12   b  of three terminal pairs  11 . 
         [0038]    On the upper surfaces of ridge-like portions  14 , distinguishing marks  15  are provided to correspond to three terminal pairs  11 . By distinguishing marks  15 , three terminal pairs  11  are associated with a positive terminal, a negative terminal, and an earth terminal. As the marks for distinguishing the positive terminal, the negative terminal, and the earth terminal, a positive sign, a negative sign, and an alphabet “E” can be used, for example. The positions of distinguishing marks  15  are not limited to the upper surfaces of ridge-like portions  14 , as long as a correspondence between three terminal pairs  11  and distinguishing marks  15  is definite. 
         [0039]    Each of terminals  12   a ,  12   b  includes conductor plates, which are screwed to terminal attachment member  10 .  FIG. 1A  shows an example in which each of terminals  12   a ,  12   b  includes two conductor plates. As an example, an internal cable of the device on which this coil-included terminal block is mounted is connected to one terminal  12   a , and an external power supply cable and an earth line are connected to other terminal  12   b . In all the terminal pairs  11 , a direction from one terminal  12   a  to other terminal  12   b  is the same. 
         [0040]      FIG. 1B  shows a cross sectional view of the coil-included terminal block according to the first embodiment perpendicular to the y direction. In a cavity  16  inside terminal attachment member  10 , a core  20  composed of a magnetic material is contained. Core  20  has an annular shape extending around a hypothetical straight line parallel to the y direction. Three coils  21  are wound around core  20 . Three coils  21  connect terminals  12   a  to respective terminals  12   b  of three terminal pairs  11 . 
         [0041]    Partition plates  13  extend to come into cavity  16  inside terminal attachment member  10 , and are disposed between adjacent coils  21 . Each of partition plates  13  is provided with a slit at a position crossing core  20 . Core  20  extends through this slit. Partition plates  13  prevent positional deviation of coils  21  and prevent contact between adjacent coils  21 . 
         [0042]    A direction in which each coil  21  is wound is set such that magnetic fluxes generated by three coils  21  are intensified with one another when current flows from terminals  12   a  to other terminals  12   b  via coils  21 . In other words, three coils  21  and core  20  construct a common mode choke coil. Core  20  has a portion having a flat plate-like shape parallel to the xy plane. Three coils  21  are wound around such a flat plate-like portion  20   a.    
         [0043]      FIG. 1C  shows a cross sectional view of the coil-included terminal block according to the first embodiment perpendicular to the x direction. Core  20  is contained in cavity  16  inside terminal attachment member  10 . Coils  21  are wound around core  20 . Terminals  12   a ,  12   b  are screwed to an upper wall of terminal attachment member  10 . Ridge-like portion  14  is provided between the pair of terminals  12   a ,  12   b . The respective ends of each coil  21  are soldered to terminals  12   a ,  12   b , whereby coil  21  connects one terminal  12   a  to other terminal  12   b.    
         [0044]      FIG. 1D  shows the equivalent circuit diagram of the coil-included terminal block according to the first embodiment. One terminal  12   a  of each of three terminal pairs  11  is connected to other terminal  12   b  via coil  21 . Three coils  21  disposed to correspond to three terminal pairs  11  construct a common mode choke coil. 
         [0045]    As an example, two terminals  12   b  corresponding to the positive and negative terminals are connected to a system power supply  30  via a power supply cable  31 . Terminal  12   b  corresponding to the earth terminal is grounded via an earth line  32 . 
         [0046]    Next, the following describes an excellent effect obtained by employing the configuration of the coil-included terminal block according to the first embodiment. 
         [0047]    In an inverter, a converter, or the like using a power semiconductor element, noise is generated due to switching of the power semiconductor element. The noise generated by the switching has a high-order frequency component of the switching frequency. According to an evaluation experiment conducted by the inventor of the present application, it was found that a high-order harmonic noise, such as 10-th or higher order harmonic noise, is propagated in a common mode not only in the power supply line including the positive line and the negative line but also in the earth line. 
         [0048]    When mounting the coil-included terminal block according to the first embodiment in an inverter, a converter, or the like, the common mode choke coil is inserted in the power supply line and the earth line. Accordingly, the high-order harmonic noise generated in the device can be suppressed from being propagated to external power supply cable  31 . 
         [0049]    When there is an interconnection extending from the common mode choke coil to a connection terminal of the external power supply cable in the device, noise may be superimposed on the interconnection between the common mode choke coil and the connection terminal. The noise thus superimposed on the interconnection leaks to the external power supply cable. In the first embodiment, the common mode choke coil is disposed in the terminal block to which external power supply cable  31  ( FIG. 1D ) is connected. Hence, the leakage of the harmonic noise generated in the device is blocked just before external power supply cable  31 . Accordingly, the leakage of the harmonic noise to power supply cable  31  can be suppressed effectively. 
         [0050]    Since distinguishing marks  15  ( FIG. 1A ) are provided in the coil-included terminal block according to the first embodiment, three terminal pairs  11  can be readily associated with the positive terminal, the negative terminal, and the earth terminal. Moreover, three terminal pairs  11  are disposed on the surface of terminal attachment member  10  to orient in the same direction. More specifically, three terminal pairs  11  are disposed such that the center axes of the screws for fixing terminals  12   a ,  12   b  of terminal pairs  11  orient in the same direction. Hence, terminals  12   a ,  12   b  of terminal pair  11  can be accessed from one direction. Accordingly, workability can be improved. 
         [0051]    Furthermore, core  20  of the coil-included terminal block according to the first embodiment includes flat plate-like portion  20   a . Flat plate-like portion  20   a  is parallel to a hypothetical plane in which terminal pair  11  is disposed. Since three coils  21  are wound around flat plate-like portion  20   a , a relative positional relation can be substantially the same between three terminal pairs  11  and three coils  21  corresponding to respective terminal pairs  11 . Accordingly, there is obtained a common mode choke coil that provides substantially the same influence over three terminal pairs  11 . 
         [0052]    Cavity  16  in terminal attachment member  10  may be filled with an insulating resin. By filling with the resin, core  20 , coils  21  and the like can be fixed to terminal attachment member  10 . 
       Second Embodiment 
       [0053]    Next, with reference to  FIG. 2A  to  FIG. 2C , the following describes a coil-included terminal block according to a second embodiment. Hereinafter, a difference from the first embodiment shown in  FIG. 1A  to  FIG. 1D  will be described and common configurations will not be described. 
         [0054]      FIG. 2A  shows a perspective view of the coil-included terminal block according to the second embodiment. While three terminal pairs  11  are attached to terminal attachment member  10  in the first embodiment, four terminal pairs  11  are attached to terminal attachment member  10  in the second embodiment. Distinguishing marks  15  are provided to associate four terminal pairs  11  with a U phase terminal, a V phase terminal, a W phase terminal, and an earth terminal. 
         [0055]      FIG. 2B  shows a cross sectional view of the coil-included terminal block according to the second embodiment perpendicular to the y axis. Four coils  21  corresponding to four terminal pairs  11  are wound around annular core  20 . Four coils  21  are connected to corresponding terminal pairs  11 . 
         [0056]      FIG. 2C  shows an equivalent circuit diagram of the coil-included terminal block according to the second embodiment. One terminal  12   a  and other terminal  12   b  of each of four terminal pairs  11  are connected to each other via coil  21 . Four coils  21  disposed to correspond to four terminal pairs  11  construct a common mode choke coil. 
         [0057]    As an example, three terminals  12   b  corresponding to the U phase terminal, the V phase terminal, and the W phase terminal are connected to a three-phase system power supply  30  via power supply cable  31 . Terminal  12   b  corresponding to the earth terminal is grounded via earth line  32 . 
         [0058]    In the second embodiment, common mode noise leaking to the three-phase AC power supply cable can be reduced. 
         [0059]    In the first embodiment, three terminal pairs  11  are fixed to terminal attachment member  10 , whereas in the second embodiment, four terminal pairs  11  are fixed to terminal attachment member  10 . Furthermore, not less than five terminal pairs  11  can be fixed to terminal attachment member  10 . In this case, coil  21  for each terminal pair  11  is contained in terminal attachment member  10 . 
       Third Embodiment 
       [0060]    Next, with reference to  FIG. 3A  and  FIG. 3B , the following describes a coil-included terminal block according to a third embodiment. Hereinafter, a difference from the first embodiment shown in  FIG. 1A  to  FIG. 1D  will be described and common configurations will not be described. 
         [0061]      FIG. 3A  shows a cross sectional view of the coil-included terminal block according to the third embodiment perpendicular to the y direction.  FIG. 3B  shows a cross sectional view of the coil-included terminal block according to the third embodiment perpendicular to the x direction. Three coils  21  are covered with a shield member  25 . More specifically, shield member  25  covers coil  21  at a lower portion and side portions. For shield member  25 , a metal plate can be used, for example. Shield member  25  is connected to one terminal  12   b  of terminal pair  11  corresponding to the earth terminal. 
         [0062]    Since coil  21  is covered with shield member  25  in the third embodiment, it is possible to reduce electromagnetic radiation from coil  21  and electromagnetic coupling between coil  21  and another component. In the third embodiment shown in  FIG. 3A  and  FIG. 3B , coil  21  is covered with shield member  25  at the lower portion and side portions; however, coil  21  may be further covered with shield member  25  at an upper portion. 
       Fourth Embodiment 
       [0063]    Next, with reference to  FIG. 4A  and  FIG. 4B , the following describes a coil-included terminal block according to a fourth embodiment. Hereinafter, a difference from the first embodiment will be described and common configurations will not be described. 
         [0064]      FIG. 4A  shows a cross sectional view of the coil-included terminal block according to the fourth embodiment perpendicular to the y direction.  FIG. 4B  shows a cross sectional view of the coil-included terminal block according to the fourth embodiment perpendicular to the x direction. In the first embodiment, three coils  21  ( FIG. 1B ) are wound around common core  20  to construct the common mode choke coil. In the fourth embodiment, three coils  21  are independent from one another. No core common among three coils  21  is disposed. Each of three coils  21  is molded by a resin, for example. 
         [0065]    Since coil  21  is inserted in terminal pair  11  corresponding to the earth terminal in the fourth embodiment, the impedance of the earth line can be increased. Accordingly, leakage current flowing to the earth line can be reduced. Further, since coil  21  is inserted in terminal pair  11  to which the power supply cable is connected, high-frequency noise can be suppressed from being propagated to the power supply cable. 
         [0066]    As coil  21  used for the coil-included terminal block according to the fourth embodiment, an air-core coil may be used or a coil with a core may be used. Moreover, in order to reduce coupling among three coils  21 , three coils  21  may be disposed such that the coil axes of three coils  21  are orthogonal to one another. In addition, as respective three coils  21 , different ring cores can be also used to reduce coupling among three coils  21 . 
         [0067]    As shown in  FIG. 5 , a shield member  25  similar to shield member  25  shown in  FIG. 3A  and  FIG. 3B  may be disposed on the coil-included terminal block according to the fourth embodiment. 
       Fifth Embodiment 
       [0068]    Next, with reference to  FIG. 6 , the following describes a coil-included terminal block according to a fifth embodiment. Hereinafter, a difference from the second embodiment shown in  FIG. 2A  to  FIG. 2C  will be described and common configurations will not be described. 
         [0069]      FIG. 6  shows a cross sectional view of the coil-included terminal block according to the fifth embodiment perpendicular to the y direction. Although four coils  21  are wound around common core  20  ( FIG. 2B ) in the second embodiment, four coils  21  are independent from one another in the fifth embodiment. 
         [0070]    In the fifth embodiment, as with the fourth embodiment shown in  FIG. 4A  and  FIG. 4B , the impedance of the earth line can be increased. Accordingly, leakage current flowing to the earth line can be reduced. Furthermore, high-frequency noise can be suppressed from being propagated to the power supply cable. 
         [0071]    As shown in  FIG. 7 , a shield member  25  similar to shield member  25  shown in  FIG. 3A  and  FIG. 3B  may be disposed on the coil-included terminal block according to the fifth embodiment. 
         [0072]    Although the present disclosure has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the scope of the present disclosure being interpreted by the terms of the appended claims.