JP6556515B2 - Resonance noise mitigation structure - Google Patents

Description

  The present invention relates to a resonance noise mitigation structure. Specifically, an external wiring having a shield coating grounded via a connector is connected to an electrical device housed in a grounded conductive casing. The present invention relates to a resonance noise mitigation structure that suppresses resonance noise that leaks to the outside through an opening of a housing into which a connector is inserted.

  Usually, in an electric vehicle or a hybrid vehicle driven by electricity or a battery, for example, external wiring for transmitting and receiving electric power between electric devices such as a motor and an inverter is connected to the electric devices via a connector. Adopted. It is known that electromagnetic wave noise (especially resonance noise) leaks outside the grounded housing by propagating along the transmission line leading to the wiring inside the housing of such electrical equipment, internal terminals, connector terminals and external wiring. It has been. In order to prevent electromagnetic noise from leaking out from such an electrical device, the casing is grounded and a shield covering such as a mesh wire covering the external wiring is grounded to shield the electromagnetic noise. . That is, a measure (EMC) is taken to eliminate the phenomenon in which unnecessary electromagnetic noise generated by the electric device interferes with the operation of other electronic devices.

  However, a current (noise current) including a high-frequency component flowing in the transmission line described above is a specific part at a portion where the impedance of the transmission line (specifically, the impedance with the ground conductor surrounding the transmission line) changes. It is known that frequency components are reflected to cause resonance. Since resonance noise generated by such resonance may interfere with the operation of other electronic devices, various countermeasures have been conventionally proposed (for example, Patent Documents 1 and 2).

JP 2009-135760 A JP-A-10-116638

  By the way, although constant resonance noise can be reduced by conventional measures, in the case of measures using a ferrite core or a choke coil, a rise in temperature may be a problem due to resonance noise absorbed by them. In particular, the transmission line of electrical equipment that sends and receives power to and from power equipment via external wiring has a large flowing noise current, so considering the problem of temperature rise, use a ferrite core or choke coil as a countermeasure against resonance noise. Therefore, there is a demand for measures for effectively reducing resonance noise.

  The problem to be solved by the present invention is to effectively reduce resonance noise that leaks from an electrical device to which external wiring is connected via a connector.

  In order to solve the above problems, the inventors of the present invention have a configuration in which an external wiring having a shield coating is connected to an electrical device housed in a ground casing (shield casing) via a connector. In order to prevent resonance noise generated in the transmission line from the internal wiring in the shielded casing to the external wiring connector from leaking to the outside, the external wiring connector reaches the opening (shield opening) inserted into the casing. We have learned that measures to reduce the impedance of transmission lines are effective.

  In view of this knowledge, the resonance noise mitigation structure of the present invention is such that an external wiring having a shield coating is connected to an electrical device housed in a grounded conductive housing via a connector, and the connector is connected to the housing. The shield cover is fixed to the housing via a conductive flange that is inserted into the housing through an opening formed in the housing, and the shield coating is connected to the housing via the flange. It is characterized in that a grounding conductor is arranged up to the opening, facing the transmission line composed of the external wiring connected to the internal wiring via a connector terminal with a space therebetween.

  That is, according to the present invention, since the grounding conductor is arranged up to the opening (shield opening) with a gap facing the transmission line made of the external wiring connected to the internal wiring of the electric device via the connector terminal, The impedance between the transmission line and the ground conductor in that portion is reduced. As a result, the resonance noise current flowing through at least the transmission line including the connector terminal in the housing and the external wiring flows through the ground circuit via the ground conductor having a small impedance. As a result, since the resonance noise current flowing from the opening (shield opening) of the housing through which the external wiring passes to the external wiring can be reduced, the resonance noise leaking to the outside can be reduced.

  In the present invention, the ground conductor is preferably a cylindrical ground conductor formed so as to surround an outer periphery of the transmission line and electrically connected to the flange. According to this, since the impedance between the transmission line and the cylindrical grounding conductor can be further reduced, the electromagnetic wave of the resonance noise flows through the cylindrical grounding conductor. Resonance noise flowing in the external wiring can be suppressed.

  Moreover, it is preferable that the said cylindrical grounding conductor is gradually formed thicker as it goes to the front-end | tip from the said flange side. According to this, since electromagnetic waves of resonance noise do not easily enter the cylindrical ground conductor, resonance noise flowing from the opening (shield opening) of the housing through which the external wiring passes to the external wiring can be suppressed.

  Furthermore, the cylindrical grounding conductor may be formed so as to gradually increase in thickness as it goes from the tip toward the flange. In this case, it is preferable that the cylindrical ground conductor is formed so that the cross-sectional size of the inner surface matches the cross-sectional size of the inner surface of the shield coating of the external wiring. According to this, resonance noise flowing from the opening (shield opening) of the housing through which the external wiring passes can be further suppressed.

  On the other hand, the connector has a cylindrical portion that is supported by the flange and has a tip opened in the housing, and a connecting portion between the external wiring and the connector terminal is accommodated in the cylindrical portion. The cylindrical ground conductor is preferably provided on the inner surface. In this case, it is preferable that the cylindrical grounding conductor is formed so as to surround the outer periphery of the internal terminal of the electric device whose tip is connected to at least the connector terminal.

  Moreover, when the cylindrical grounding conductor is formed so as to surround the outer periphery of the internal terminal of the electric device connected to the connector terminal, it is preferable that the cylindrical grounding conductor is formed with the tip extended in a horn shape. According to this, since the change in the impedance of the transmission line, which is the cause of the resonance noise, can be moderated, it is possible to reduce the resonance noise by suppressing the reflection of the noise current.

  ADVANTAGE OF THE INVENTION According to this invention, the resonance noise which leaks from the electric equipment with which external wiring is connected via a connector can be reduced or reduced effectively.

(A) is a block diagram of the resonance noise mitigation structure of Example 1 of this invention, (b) is sectional drawing in Ib-Ib of (a), (c) is sectional drawing in Ic-Ic of (a). It is. It is the block diagram which incorporated the resonance noise mitigation structure of Example 1 in the housing | casing of the electric equipment. In the resonance noise mitigation structure of Example 1, it is a diagram which shows the relationship between the intensity | strength of the conduction noise which leaks from a connector at the time of supplying electric power from the electric equipment side, and a frequency. It is a block diagram of the resonance noise mitigation structure of Example 2 of this invention. It is the block diagram which incorporated the resonance noise mitigation structure of Example 2 in the housing | casing of an electric equipment. (A) is the block diagram of the resonance noise mitigation structure of Example 3 of this invention, (b) is the block diagram of the resonance noise mitigation structure of Example 4 of this invention, (c) is the resonance of Example 5 of this invention. It is a block diagram of a noise mitigation structure.

  Hereinafter, the present invention will be described based on examples.

  1 is an example applied to a high-voltage connector used in an electric vehicle or a hybrid vehicle. However, the application of the resonance noise mitigation structure of the present invention is not limited to a high voltage connector. In short, the resonance noise mitigation structure is based on a current containing a high frequency component flowing in a transmission line from an internal wiring to an external wiring of an electric device having an inverter or the like. It goes without saying that the generated resonance noise can be applied to a resonance noise mitigation structure that suppresses leakage from the shield opening of the casing of the electrical device to the outside of the casing.

  As shown in FIG. 1 and FIG. 2, the resonance noise mitigation structure 1 is a connector for connecting an external wiring 5 having a shield coating 4 to an internal terminal 3 of a conductive housing 2 in which an electrical device is accommodated and grounded. 6 is provided. The housing 2 is formed in, for example, a rectangular parallelepiped, and a resin tube portion 9 of the connector 6 is inserted into the housing 2 from an opening (shield opening) 8 formed in the housing wall 7. The internal terminal 3 is connected to the internal wiring 15 through which the motive current of the electrical device shown in FIG. 2 flows. The cylindrical portion 9 of the connector 6 is attached to a metal flange 10 having conductivity, for example. The flange 10 has a through hole (not shown) into which the external wiring 5 is inserted.

  The external wiring 5 positioned in the tube portion 9 has the shield coating 4 peeled off to expose the insulating layer. In the present embodiment, as shown in FIG. 3C, the external wiring 5 is composed of three external wirings 5a to 5c, and the shield coating 4 surrounds the entire outer periphery of the three external wirings 5a to 5c. Is provided. The shield coating 4 includes a braided wire 4a that forms a shield layer and an outer skin 4b that protects the braided wire 4a. The insulating layer is stripped off and the connector terminals 11 (a to c) are connected to the tips of the external wirings 5a to 5c, for example, by pressure bonding.

  Here, the detailed structure of the characteristic part of the resonance noise mitigation structure 1 of the first embodiment will be described. A cylindrical portion 9 having an open end of the connector 6 supported by the flange 10 is inserted into the space of the housing 2. Further, a connecting portion between the external wiring 5 and the connector terminal 11 is accommodated in the cylindrical portion 9. A cylindrical ground conductor 12 is provided on the inner surface of the cylindrical portion 9. The cylindrical ground conductor 12 is disposed to face the connector terminal 11 with a space therebetween. Further, in the first embodiment, the tip of the cylindrical ground conductor 12 extends beyond the connecting portion between the external wiring 5 and the connector terminal 11 so as to surround the internal terminal 3. In particular, in the first embodiment, the cylindrical grounding conductor 12 is formed with its tip widened in a horn shape. The connector terminal 11 is fastened to the internal terminal 3 with a bolt 16 and a nut 17. The cylindrical ground conductor 12 is electrically connected to the flange 10.

  The detailed configuration and operation of the resonance noise mitigation structure 1 of Example 1 formed in this way will be described with reference to FIG. The casing 2 has irregularities 2a to 2c formed on the inner surface. On the other hand, the cylindrical portion 9 of the connector 6 is inserted into the casing 2 from the opening 8 formed in the casing wall 7, and the flange 10 The connector 6 is fixed to the housing 2 by screwing bolts 13 into screw holes formed on the outer peripheral edge of the opening 8. As a result, the flange 10 is electrically connected to the grounded casing 2 and grounded, and the shield coating 4 and the cylindrical ground conductor 12 of the external wiring 5 are held at the ground potential. On the other hand, the internal terminal 3 is connected to an internal wiring 15 connected to an electric device housed in the housing 2.

  As a result, a power current including a high frequency (hereinafter referred to as a noise current) flows through the transmission line from the internal wiring 15 to the internal terminal 3, the connector terminal 11, and the external wiring 5. The characteristic impedance of the transmission line is not affected by the unevenness 2a to 2c on the inner surface of the housing 2 by the housing wall 7 or the cylindrical grounding conductor 12 which is the outer conductor of the ground potential, and the arrow shown in FIG. Thus, it changes uniformly or gently along the transmission direction. Thereby, reflection of noise current in the transmission direction of the transmission line is suppressed, electromagnetic wave energy reaching the internal terminal 3 is efficiently transmitted to the connector terminal, and resonance noise is greatly reduced. Even if electromagnetic wave noise enters the cylindrical grounding conductor 12, since the impedance of the connector terminal 11 is low, the influence of the resonance noise is slight. Moreover, since the cylindrical grounding conductor 12 forms a waveguide, it can also be expected to have a high frequency noise cutoff effect.

  Incidentally, when the horn-shaped cylindrical grounding conductor 12 is not provided, the impedance viewed from the transmission line is due to the unevenness of the inner surface of the housing 2 between the transmission line and the housing wall 7 that is the outer conductor of the ground potential. In addition, there are a plurality of sites that change greatly. The noise current is repeatedly reflected at a portion where the impedance changes greatly, and resonance noise of a specific frequency is generated. In this respect, according to the resonance noise alleviating structure 1 of the first embodiment, since a large change in impedance is suppressed, the resonance noise can be attenuated.

  Further, according to the first embodiment, since the cylindrical ground conductor 12 is provided on the inner surface of the cylindrical portion 9 of the connector 6, it is possible to reduce the impedance viewed from the transmission line including the connector terminal 11 and the external wiring 5. it can. As a result, the resonance noise current flowing through the transmission line flows to the ground circuit via the ground conductor 12 having a small impedance, so that the resonance noise flowing from the opening 8 of the housing 2 through the external wiring 5 to the external wiring 5 side. Current can be suppressed and resonance noise leaking to the outside can be reduced.

  FIG. 3 shows the relaxation of the resonance phenomenon when the resonance noise mitigation structure 1 of the first embodiment is provided and when it is not provided. FIG. 3 is a diagram showing the relationship between the received power (conducted noise intensity) and the frequency of conduction noise leaking from the connector 6 when power is supplied from the housing 2 side, and the resonance noise mitigation structure 1 is not provided. In this case, as shown by the curve 21, a resonance phenomenon occurs at a specific frequency. On the other hand, when the resonance noise mitigating structure 1 is provided, as shown by the curve 22, it can be seen that the resonance phenomenon at a specific frequency is relaxed.

  That is, according to the resonance noise alleviating structure 1 of the first embodiment, it is shown that the transmission performance is improved by the impedance matching action, and the resonance noise is reduced. Further, the cylindrical ground conductor 12 extended to the inside of the housing 2 has a function of reducing the impedance of the internal terminal 3 and the connector terminal 11 with respect to the ground conductor, so that even if high-frequency noise travels to the back of the terminal, a loop is formed. This has the effect of reducing the influence of noise. In particular, as in the cylindrical ground conductor 12 of the resonance noise mitigation structure 1 of the first embodiment, the distal end is expanded in a horn shape for impedance matching, and the proximal end is matched with the oval aperture of the braided wire 4a of the shield coating 4. For example, it has an effect of attenuating larger resonance noise.

  In the first embodiment, an example in which the connection between the internal terminal 3 and the connector terminal 11 is fastened with a screw has been shown. However, the present invention is not limited to this, and a connection using male and female connector terminals is adopted. May be.

  FIG. 4 is a configuration diagram of the resonance noise mitigation structure 30 according to the second embodiment of the present invention. The cylindrical grounding conductor 12 of Example 1 has the tip portion widened in a horn shape, but the cylindrical grounding conductor 31 of Example 2 does not widen the tip portion in a horn shape, and is formed on the inner surface of the tubular portion 9 of the connector 6. It is formed in a linear shape with the combined shape. Since the other configuration is the same as that of the first embodiment, the same reference numerals are given to the components and the description thereof is omitted. As shown in FIG. 5, the tip of the cylindrical ground conductor 21 of the second embodiment is applied to the same casing 2 as the casing 2 of the first embodiment up to the same position as the first embodiment. It is extended. However, it is preferable to change the tip position according to the part where the impedance changes according to the inner shape of the housing 2.

  According to the second embodiment, similarly to the first embodiment, the transmission performance is improved by the impedance matching action, and the resonance noise can be reduced. Further, the cylindrical grounding conductor 31 extended to the inside of the housing 2 has a function of reducing the impedance of the internal terminal 3 and the connector terminal 11 with respect to the grounding conductor. Has the effect of reducing the influence of loop noise. In addition, although the front-end | tip is not expanded in the shape of a horn like the cylindrical grounding conductor 12 of the resonance noise mitigation structure 1 of Example 1, depending on the inner surface shape of the housing | casing 2, the suppression effect of the resonance noise of Example 1 is effective. Not much change. Moreover, since the base end is made to correspond to the aperture of the braided wire 4a of the shield coating 4, the resonance noise at this part can be attenuated.

  As described in the first embodiment, since the cylindrical ground conductor 31 is provided on the inner surface of the cylindrical portion 9 of the connector 6, the impedance viewed from the transmission line including the connector terminal 11 and the external wiring 5 is reduced. Therefore, the resonance noise current flowing from the opening 8 of the housing 2 through which the external wiring 5 passes to the external wiring 5 side can be suppressed, and the resonance noise leaking to the outside can be reduced.

  FIG. 6A shows a configuration diagram of the resonance noise mitigation structure 40 according to the third embodiment of the present invention. The difference between the third embodiment and the second embodiment is that in the second embodiment, the thickness of the cylindrical grounding conductor 41 is uniform from the base connected to the flange 10 to the inside of the cylindrical portion 9 of the connector 6. In the third embodiment, the thickness is gradually increased from the base portion of the cylindrical portion 9 toward the tip of the cylindrical ground conductor 41. Since the other configuration is the same as that of the second embodiment, the same reference numerals are given to the components and the description thereof is omitted.

  According to the third embodiment, since the oval diameter of the tip opening of the cylindrical ground conductor 41 is reduced, electromagnetic noise in the housing space is less likely to enter the cylindrical ground conductor 41, resulting in a flange. Resonance noise leaking from the 10 shield openings can be reduced. Further, as described in the first embodiment, since the cylindrical ground conductor 41 is provided on the inner surface of the cylindrical portion 9 of the connector 6, the impedance viewed from the transmission line including the connector terminal 11 and the external wiring 5 is reduced. Therefore, the resonance noise current flowing from the opening 8 of the housing 2 through which the external wiring 5 passes to the external wiring 5 side can be suppressed, and the resonance noise leaking to the outside can be reduced.

  FIG. 6B shows a configuration diagram of the resonance noise mitigation structure 50 according to the fourth embodiment of the present invention. The fourth embodiment is different from the third embodiment in that the thickness of the cylindrical ground conductor 51 is gradually increased from the tip toward the base connected to the flange 10. Since the other configuration is the same as that of the third embodiment, the same reference numerals are given to the components and the description thereof is omitted. According to the fourth embodiment, the oval diameter of the base portion of the cylindrical ground conductor 51 connected to the flange 10 can be matched with the diameter of the braided wire 4 a of the shield coating 4 of the external wiring 5. Thereby, the shield opening of the connection part of the cylindrical ground conductor 51 and the shield coating 4 can be eliminated. Resonance noise leakage from the shield opening of the connector 6 of the external wiring 5 can be reduced. Further, as described in the first embodiment, since the cylindrical ground conductor 51 is provided on the inner surface of the cylindrical portion 9 of the connector 6, the impedance viewed from the transmission line including the connector terminal 11 and the external wiring 5 is reduced. Therefore, the resonance noise current flowing from the opening 8 of the housing 2 through which the external wiring 5 passes to the external wiring 5 side can be suppressed, and the resonance noise leaking to the outside can be reduced.

  FIG. 6C illustrates a configuration diagram of the resonance noise mitigation structure 60 according to the fifth embodiment of the present invention. The ground conductors of the resonance noise mitigation structures shown in Examples 1 to 4 were all cylindrical ground conductors, but the present invention is not limited to this, and as shown in FIG. The grounding conductor 61 is provided in a part of the circumferential direction. Since the other configuration is the same as that of the second embodiment, the same reference numerals are given to the components and the description thereof is omitted.

  According to the fifth embodiment, since the ground conductor 61 is disposed facing the connector terminal 11 to which the external wiring 5 is connected with a space therebetween, the impedance between the connector terminal 11 and the ground conductor 61 is reduced. . Thereby, the resonance noise current flowing through the transmission line including the internal wiring 15, the internal terminal 3, the connector terminal 11, and the external wiring 5 of the electric device is supplied to the ground circuit via the ground conductor 61 having a small impedance. As a result, since the resonance noise current flowing from the opening 8 of the housing 2 through which the external wiring 5 passes to the external wiring 5 side can be suppressed, the resonance noise leaking to the outside can be reduced. The effect of this point is the same also in the resonance noise mitigation structures of Examples 1 to 4.

  As described above, the resonance noise mitigation structure of the present invention has been described based on Examples 1 to 5. However, the resonance noise mitigation structure of the present invention has the ground conductors 12, 31, 41, 51 on the inner surface of the cylindrical portion 9 of the connector 6. It is characterized in that the front end thereof is extended to face the connector terminal 11 and further to the internal terminal 3. Thereby, the resonance noise from the inside of the housing 2 is attenuated, and the resonance noise current flowing from the opening 8 of the housing 2 through which the external wiring 5 passes to the external wiring 5 side can be suppressed.

  The cylindrical grounding conductors of Examples 1 to 4 are cylindrical examples having an oval cross section, but the present invention is not limited to this, and the cross section is a cylinder having a rectangular, square, or polygonal shape. May be.

  As described above, the present invention has been described based on the embodiments, but the present invention is not limited thereto, and can be implemented in a form that is modified or changed within the scope of the gist of the present invention. It will be apparent to those skilled in the art that such variations or modifications are within the scope of the claims.

1 Resonance Noise Mitigation Structure 2 Housing 3 Internal Terminal 4 Shield Cover 5 External Wiring 6 Connector 7 Housing Wall 8 Opening (Shield Opening)
9 Tubular portion 10 Flange 11 Connector terminal 12 Tubular ground conductor 15 Internal wiring 31, 41, 51 Tubular ground conductor 61 Ground conductor

Claims (7)

An external wiring having a shield coating is connected via a connector to an electrical device housed in a grounded conductive housing, and the connector is inserted into the housing through an opening formed in the housing to conduct electricity. Fixed to the housing through a flange having the property, the shield coating is connected to the housing through the flange,
A ground conductor facing at an interval along a power transmission line including at least the external wiring located in the housing and a connector terminal connected to the external wiring is provided to the position of the opening,
The resonant noise mitigating structure , wherein the ground conductor is a cylindrical ground conductor formed so as to surround an outer periphery of the transmission line and electrically connected to the flange . 2. The resonance noise mitigating structure according to claim 1 , wherein the cylindrical grounding conductor is formed so as to gradually increase in thickness from the flange side toward the tip. 2. The resonance noise mitigating structure according to claim 1 , wherein the cylindrical ground conductor is formed so as to gradually increase in thickness from the tip toward the flange side. 4. The resonance noise mitigating structure according to claim 3 , wherein the cylindrical ground conductor is formed so that a cross-sectional size of an inner surface thereof matches a cross-sectional size of an inner surface of the shield coating of the external wiring. The connector has a cylindrical portion that is supported by the flange and has a tip opened in the housing, and a connecting portion between the external wiring and the connector terminal is accommodated in the cylindrical portion, and is formed on an inner surface of the cylindrical portion. The resonance noise mitigation structure according to any one of claims 1 to 4 , wherein the cylindrical ground conductor is provided. 6. The resonance noise mitigating structure according to claim 5 , wherein the cylindrical grounding conductor is formed so as to surround at least an outer periphery of an internal terminal of the electric device connected to the connector terminal. The resonance noise mitigating structure according to claim 5 or 6 , wherein the cylindrical grounding conductor is formed such that a tip thereof is expanded in a horn shape.

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