Shielded structure and shielded connector

Abstract

To suppress noise in a frequency band related to communication between the power output and input sides.SOLUTION: A shield structure includes a conductive shield that covers a conductor that supplies power to an input portion in a vehicle where power is input, a connection portion that electrically connects the shield to a conductive housing that covers the input portion, and an insulating portion that provides insulation between the shield and the housing, and a resonant circuit is formed by an inductance component of the shield and a capacitance component of the insulating portion, and the frequency of noise in the vehicle is included in a suppression band that includes the resonant frequency of the resonant circuit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a shield structure and a shield connector. [Background technology]

[0002] An example of an invention relating to the shielding of electromagnetic waves generated in a vehicle is disclosed in Patent Document 1. The shielded connector disclosed in Patent Document 1 has a housing made of insulating synthetic resin and a shield shell made of conductive metal, and the shield shell is fixed to a metal case by bolts. The shield shell also has a protrusion that is fitted into a recess in the case. By fixing the shield shell to the case by bolts with the protrusion inserted into the recess in the case, the occurrence of a gap between the shield shell and the case is suppressed, and a decrease in shielding performance is prevented. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-76438 A Summary of the Invention [Problem to be solved by the invention]

[0004] Automobiles are equipped with a great number of electrical components, and the electrical components use a variety of signal frequencies for communication. For example, one communication standard used in automobiles is LIN (Local Interconnect Network), and communication according to this standard is performed at a communication frequency in the kHz band. Another communication standard used in automobiles is Bluetooth (registered trademark), and communication according to this standard is performed at a communication frequency in the GHz band. As described above, since communication is performed at various communication frequencies in automobiles, it is important that harnesses and connectors related to the connection of electrical components have noise countermeasures against the communication frequency band.

[0005] The shielded connector disclosed in Patent Document 1 has a shielded shell fixed to a metal housing with bolts, which reduces the gap between the housing and the shielded shell and may reduce radiated noise in the GHz band. However, there is an issue that this does not contribute to reducing radiated noise in frequency bands lower than the GHz band.

[0006] The present invention has been made in view of the above, and has an object to suppress noise in a frequency band related to communication between the output side and input side of power. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the shielding structure of the present invention comprises a conductive shield covering a conductor that supplies power to an input section in a vehicle where power is input, a connection section that electrically connects the shield to a conductive housing that covers the input section, and an insulating section that provides insulation between the shield and the housing, wherein a resonant circuit is formed by an inductance component of the shield and a capacitance component of the insulating section, and the frequency of noise in the vehicle is included in a suppression band that includes the resonant frequency of the resonant circuit.

[0008] In the shield structure according to one aspect of the present invention, an insulating layer having insulating properties may be provided on at least a part of a surface of the shield facing the housing.

[0009] In the shield structure according to one aspect of the present invention, at least one of the shield and the housing may have a magnetic material.

[0010] The shielded connector of the present invention has any one of the shielded structures described above, wherein the conductor consists of a first conductor connected to the output portion of the power and a second conductor connected to the input portion, and has a conductor connection portion connecting the first conductor and the second conductor. Effect of the Invention

[0011] According to the present invention, noise in a frequency band related to communication between the output side and input side of power can be suppressed. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic cross-sectional view of a shield structure according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of the arrangement of the first insulating portion. [Diagram 3] FIG. 3 is a schematic cross-sectional view of a shield structure according to a modified example. [Figure 4] FIG. 4 is a schematic cross-sectional view of a shield structure according to a modified example. [Diagram 5] FIG. 5 is a schematic cross-sectional view of a shielding structure according to a modified example. [Figure 6A] FIG. 6A is a graph showing the frequency characteristics of the first embodiment. [Figure 6B] FIG. 6B is a graph showing the frequency characteristics of the second embodiment. [Figure 6C] FIG. 6C is a graph showing the frequency characteristics of the third embodiment. [Figure 6D] FIG. 6D is a graph showing the frequency characteristics of the fourth embodiment. [Figure 6E] FIG. 6E is a graph showing frequency characteristics of the comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiment described below. In addition, in the description of the drawings, the same or corresponding elements are appropriately assigned the same reference numerals. Furthermore, it should be noted that the drawings are schematic, and the dimensional relationship of each element may differ from the actual one. There may also be parts in which the dimensional relationship and ratio are different between the drawings.

[0014] [Embodiment] FIG. 1 is a schematic diagram of a cross section of a shield structure 1 according to an embodiment of the present invention. The shield structure 1 is a structure that suppresses noise between an output side that outputs electric power in a vehicle and an input side that receives electric power. For example, in the case of an electric vehicle or a hybrid vehicle in which the wheels are driven by a motor, the output side of electric power is a secondary battery provided in the vehicle, and the input side of electric power is an inverter that drives the motor. The output side of electric power may be a charger that charges the secondary battery, and the input side of electric power may be the secondary battery. The shield structure 1 is composed of a housing 12, a first shield 13, a fixing portion 13a, a metal plate 14, a first insulating portion 15, and a bolt 16. The shield structure 1 may also include a second shield 22.

[0015] The first electric wire 21 is an electric wire connected to the output side of the electric power. The first electric wire 21 is formed of a core wire having electrical conductivity and formed by twisting a plurality of wires having a circular cross section along the radial direction, and an insulating sheath covering the core wire. The core wire of the first electric wire 21 is, for example, copper, but may be formed of another metal having electrical conductivity.

[0016] The second shield 22 is a shield that covers the first electric wire 21, and is made of a metal having electrical conductivity. The second shield 22 is made of, for example, aluminum, but may be made of other metals having electrical conductivity. The second shield 22 covers a portion of the first electric wire 21 that is closer to the output side than the first shield 13.

[0017] The second electric wire 31 is formed of a core wire formed by twisting a plurality of conductive wires having a circular cross section along the radial direction, and an insulating sheath covering the core wire. The core wire of the second electric wire 31 is, for example, copper, but may be formed of other conductive metals. The input unit 33 is an inverter circuit, and power is input via the first electric wire 21 and the second electric wire 31. The housing 32 is a housing that houses the input unit 33, which is an inverter circuit, and is formed of a conductive metal. The housing 32 also houses a portion of the second electric wire 31 that is on the input side of the first shield 13.

[0018] The conductor connection portion 11 is a terminal that electrically connects the core wire of the first electric wire 21 and the core wire of the second electric wire 31, and is formed of a metal having electrical conductivity. The conductor connection portion 11 is an example of a connector according to the present invention. Moreover, a configuration in which the shield structure 1 houses the conductor connection portion 11 is an example of a shield connector according to the present invention. The housing 12 is formed of a synthetic resin having insulating properties. The synthetic resin forming the housing 12 is, for example, polyethylene, but may be other synthetic resins. The conductor connection portion 11, the end of the first electric wire 21, and the end of the second electric wire 31 are housed inside the housing 12. The first shield 13 is formed of a metal having electrical conductivity, and houses the housing 12 inside. The first shield 13 is formed of, for example, aluminum, but may be other metals having electrical conductivity. The first shield 13 includes a fixing portion 13a. The fixing portion 13a is formed integrally with the first shield 13 and protrudes upward from the first shield 13, and has a hole through which the bolt 16 passes. Metal plate 14 is made of a conductive metal and formed into a plate shape, and is housed inside first shield 13. Bolt 16 is a bolt that fixes first shield 13 to housing 32. Bolt 16 is passed through a hole provided in fixing portion 13a and inserted into a screw hole provided in housing 32, and fixes first shield 13 to housing 32. Fixing portion 13a and bolt 16 are an example of a connecting portion according to the present invention.

[0019] FIG. 2 is a diagram showing an example of the arrangement of the first insulating portion 15. The first insulating portion 15 is formed of, for example, rubber having insulating properties. The first insulating portion 15 is arranged between the first shield 13 and the housing 32. Note that, although an example in which four first insulating portions 15 are arranged is shown in FIG. 2, the number of first insulating portions 15 arranged between the first shield 13 and the housing 32 may be less than four or five or more. In addition, the arrangement position of the first insulating portion 15 shown in FIG. 2 is one example, and the arrangement position of the first insulating portion 15 may be another position in contact with the housing 32 in a region of the first shield 13 facing the housing 32. By arranging the first insulating portion 15 between the first shield 13 and the housing 32, an electrically conductive portion and a region insulated by the first insulating portion 15 are formed between the first shield 13 and the housing 32.

[0020] In the shield structure 1, at least the first shield 13 and the second shield 22 have an inductance component. In addition, in the shield structure 1, a first insulating section 15 is provided between the first shield 13 and the housing 32 to intentionally insulate the first shield 13 from the housing 32, so that the first insulating section 15 has a capacitance component. The first insulating section 15 is an example of an insulating section according to the present invention. In the shield structure 1, the inductance component and the capacitance component form a filter by LC series resonance.

[0021] If the resonant frequency of this filter is f, the capacitance component between the first shield 13 and the housing 32 is C, and the inductance component on the output side of the housing 32 is L, then the resonant frequency of the filter due to LC series resonance is f=1 / (2π(LC) 1 / 2) In the shield structure 1, by adjusting the inductance component and the capacitance component, it is possible to reduce the impedance in the suppression band, which is a frequency band including the resonance frequency, and reduce noise at frequencies included in the suppression band. Therefore, by adjusting the inductance component and the capacitance component so that the frequency of the noise to be reduced in the vehicle is included in the suppression band, it is possible to reduce noise at a predetermined frequency. Here, the suppression band is a frequency band including the resonance frequency, and in which the noise level is within a predetermined range from the noise level of the resonance frequency. The range of the suppression band differs depending on the Q value of the resonance circuit formed by the inductance component and the capacitance component, and is, for example, within a range of ±50% of the target frequency.

[0022] The inductance component of the above-mentioned filter may be adjusted by changing at least one of the length, width, and height of the first shield 13 to adjust the inductance component of the first shield 13 and adjust the resonance frequency of the LC series resonance. The resonance frequency of the filter may be adjusted by increasing the magnetic permeability of the first shield 13 using a magnetic material such as iron, cobalt, or nickel. The magnetic material may be added as an alloy to the material of the first shield 13, or may be plated on the first shield 13. The inductance component of the above-mentioned filter may be adjusted by making the metal plate 14 a magnetic material, or by including a magnetic material in the housing 12. The inductance component of the above-mentioned filter may be adjusted by using a magnetic material in the parts that form the shield structure 1. For example, the inductance component of the above-mentioned filter may be adjusted by using a magnetic material in the bolt 16 or a washer (not shown) used for the bolt 16, or the inductance component of the above-mentioned filter may be adjusted by using a magnetic material in the conductor connection portion 11. Also, a magnetic material may be attached to the first electric wire 21 to adjust the inductance component of the filter, or a magnetic material may be added to the core wire of the first electric wire 21 to adjust the inductance component of the filter. Also, the inductance component of the filter may be adjusted by plating the core wire of the first electric wire 21 with a magnetic material. Also, a magnetic material may be included in the housing 32 to adjust the inductance component of the filter, or the housing 32 may be plated with a magnetic material to adjust the inductance component of the filter.

[0023] The capacitance component of the filter may be adjusted by adjusting the thickness of the first insulating portion 15 or the area of ​​the portion of the first insulating portion 15 that contacts the housing 32, thereby adjusting the resonance frequency of the LC series resonance. The capacitance component of the filter may be adjusted by forming an oxide film having insulating properties on the surface 13b of the first shield 13 that faces the housing 32. For example, when the first shield 13 is made of aluminum, this oxide film may be a naturally formed oxide film or an oxide film formed by anodizing. By forming an oxide film having insulating properties on the surface 13b of the first shield 13, the dielectric constant is reduced, and the resonance frequency of the filter can be increased. The capacitance component of the filter may be adjusted by adjusting the area of ​​this oxide film. This oxide film is an example of an insulating layer according to the present invention. The capacitance component of the filter may be adjusted by adjusting the distance between the first shield 13 and the housing 32 by providing irregularities on the surface 13b. Furthermore, when the first shield 13 is formed by casting, a region in which the surface roughness is reduced by polishing the surface 13b after casting and a region in which the surface roughness is large without polishing may be provided, and the capacitance component of the filter described above may be adjusted by the area of ​​the region in which the polishing is not performed. Furthermore, the capacitance component of the filter described above may be adjusted by adjusting the distance between the first shield 13 and the housing 32 by providing irregularities on the surface of the housing 32 facing the surface 13b. Furthermore, the capacitance component of the filter described above may be adjusted by applying a resin to the surface of the housing 32 facing the surface 13b and changing the area to which the resin is applied. This resin layer is an example of an insulating layer according to the present invention.

[0024] In addition, a plurality of parts having different distances between the surface 13b and the housing 32 may be provided to allow the filter to have a plurality of resonance frequencies. A plurality of types of first insulating parts 15 made of different materials may be prepared, and a plurality of types of first insulating parts 15 may be disposed between the surface 13b and the housing 32, allowing the filter to have a plurality of resonance frequencies. A plurality of types of first insulating parts 15 having different thicknesses and areas may be prepared, and a plurality of types of first insulating parts 15 having different thicknesses and areas may be disposed between the surface 13b and the housing 32, allowing the filter to have a plurality of resonance frequencies.

[0025] 3 is a schematic diagram of a cross section of a shield structure 1A according to a modified example of the present invention. The shield structure 1A is composed of a second shield 22, a housing 12, a first shield 13, a fixing portion 13a, a metal plate 14, a first insulating portion 15, a bolt 16, and a second insulating portion 23. The shield structure 1A differs from the shield structure 1 in that the second insulating portion 23 is provided between the second shield 22 and the first shield 13. The second insulating portion 23 is formed of, for example, rubber having insulating properties, and has a capacitance component of the filter due to LC series resonance, similar to the first insulating portion 15. By adjusting the thickness, area, and material of the second insulating portion 23, the capacitance component of the filter described above can be adjusted, and the resonance frequency can be changed.

[0026] 4 is a schematic diagram of a cross section of a shield structure 1B according to a modified example of the present invention. The shield structure 1B is composed of a first shield 13B, a fixing portion 13a, a first insulating portion 15, and a bolt 16. The shield structure 1B may include a second shield 22. The shield structure 1B differs from the shield structure 1 in that it does not include the conductor connection portion 11, the housing 12, and the metal plate 14. The shield structure 1B also differs from the shield structure 1 in that it includes a first shield 13B instead of the first shield 13, and a third electric wire 41 instead of the second electric wire 31 and the first electric wire 21.

[0027] The first shield 13B is made of aluminum, for example, and the third electric wire 41 penetrates from the power output side to the power input side. The third electric wire 41 is made of a core wire formed by twisting a plurality of conductive wires having a circular cross section along the radial direction, and an insulating sheath covering the core wire. One end of the third electric wire 41 is connected to the power output side, and the other end is connected to the power input side. In the shield structure 1B, the first shield 13B has an inductance component of the above-mentioned filter, and the first insulating part 15 has a capacitance component of the above-mentioned filter. In the shield structure 1B as well, a filter by LC series resonance is formed by the inductance component and the capacitance component, and noise of frequencies included in the suppression band can be reduced.

[0028] FIG. 5 is a schematic diagram of a cross section of a shield structure 1C according to a modified example of the present invention. The shield structure 1C is composed of a housing 12, a first shield 13C, a fixing portion 13a, and a bolt 16. The second shield 22 may be included in the shield structure 1C. The shield structure 1C may also be configured to include a second insulating portion 23. The shield structure 1C has a first shield 13C instead of the first shield 13, and differs from the shield structure 1 in that it does not have a metal plate 14 and a first insulating portion 15. The first shield 13C is made of aluminum, for example, and differs from the first shield 13 in that it does not contain the metal plate 14. The first shield 13C has a plurality of recesses 17 formed on a surface facing the housing 32. When the first shield 13C is fixed to the housing 32 by the bolt 16, a gap is formed between the first shield 13C and the housing 32 due to the recesses 17. In the shield structure 1C, the first shield 13C has an inductance component of the above-mentioned filter, and the gap formed by the recess 17 has a capacitance component of the above-mentioned filter. In the shield structure 1C as well, a filter is formed by LC series resonance due to the inductance component and the capacitance component, and noise at frequencies included in the suppression band can be reduced.

[0029] In the connector disclosed in Patent Document 1, the shield shell is fixed to the housing without any gap, but in the present invention, LC series resonance is generated by intentionally insulating at least a part between first shield 13 and housing 32, so that noise can be reduced in a specific frequency band compared to the connector of Patent Document 1. The resonant frequency of the LC series resonance is preferably in the range of 1 kHz to 1 GHz, and more preferably in the range of 10 kHz to 1 GHz.

[0030] [Example] The inventors of the present invention have prepared a first embodiment to a fourth embodiment and a comparative example by changing the inductance component and capacitance component of the above-mentioned filter for the shield structure 1C, and evaluated the frequency characteristics of each. The first embodiment is a structure in which the core wires of the second electric wire 31 and the first electric wire 21 in the shield structure 1C are copper, the material of the housing 12 is polyethylene, and the material of the first shield 13C and the second shield 22 is aluminum. In the first embodiment, the number of bolts 16 for fixing the first shield 13C to the housing 32 in the shield structure 1C is one, and as shown in FIG. 5, the first insulating part 15 is not arranged, and a gap is formed between the surface 13b and the housing 32. The second embodiment is a structure in which the material of the first shield 13C and the second shield 22 is iron in the configuration of the first embodiment. The third embodiment is a structure in which an insulating hardening resin is further applied to a part of the surface of the housing 32 facing the surface 13b in the configuration of the first embodiment. The fourth embodiment has a structure in which an insulating curable resin is further applied to a part of the surface of housing 32 facing surface 13b in the configuration of the second embodiment. The comparative example has a structure in which first shield 13C is fixed to housing 32 without any gaps in the first embodiment.

[0031] For the evaluation of the frequency characteristics, noise power was input to the first electric wire 21, an electromagnetic field probe was fixed at a position 5 cm away from the first shield 13C, and the frequency characteristics of the output of the electromagnetic field probe were measured. A spectrum analyzer GSP-9330 manufactured by GW Instec was used for measuring the frequency characteristics.

[0032] Fig. 6A is a graph showing the measurement results of the frequency characteristics of Example 1, Fig. 6B is a graph showing the measurement results of the frequency characteristics of Example 2, Fig. 6C is a graph showing the measurement results of the frequency characteristics of Example 3, Fig. 6D is a graph showing the measurement results of the frequency characteristics of Example 4, and Fig. 6E is a graph showing the measurement results of the frequency characteristics of a comparative example.

[0033] In the comparative example, since there is no gap or insulator between first shield 13C and housing 32, there is no capacitance component between first shield 13C and housing 32, and LC series resonance does not occur. For this reason, as shown in Fig. 6E, there is no frequency band where the noise level is reduced in the frequency characteristics of the comparative example, and it is clear that noise cannot be reduced.

[0034] On the other hand, in the first embodiment, the noise level is reduced at the resonance frequency of the filter due to the series connection of the inductance component and the capacitance component. In the second embodiment, in which the materials of the first shield 13C and the second shield 22 are changed from those of the first embodiment, the inductance component is different from that of the first embodiment, and therefore the noise level is reduced in a lower frequency band than in the first embodiment. In other words, the resonance frequency can be adjusted by simply changing the materials of the first shield 13C and the second shield 22, and the frequency band of the noise to be reduced can be changed.

[0035] In addition, in the third embodiment, which has a different capacitance component from the first embodiment, the noise level is reduced in a higher frequency band than in the first embodiment. In addition, in the fourth embodiment, which has a different capacitance component from the second embodiment, the noise level is reduced in a higher frequency band than in the second embodiment. In other words, the resonance frequency can be adjusted by simply changing the insulation configuration between surface 13b and housing 32, and the frequency band of the noise to be reduced can be changed.

[0036] [Variations] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment and can be implemented in various other forms. For example, the above-mentioned embodiment may be modified as follows to implement the present invention. The above-mentioned embodiment and the following modifications may be combined with each other. The present invention also includes a configuration in which the components of the above-mentioned embodiments and modifications are appropriately combined. Further effects and modifications can be easily derived by a person skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-mentioned embodiment and modifications, and various modifications are possible.

[0037] In the present invention, the second electric wire 31 and the first electric wire 21 may be replaced with a bus bar. In addition, the bus bar may be plated with tin, nickel, or the like.

[0038] In the present invention, the inductance component of the aforementioned filter may also be adjusted by changing the shape of the second shield 22. Also, the inductance component of the aforementioned filter may be adjusted by including a magnetic material in the second shield 22. By adjusting the inductance component of the second shield 22 as well, the resonant frequency of the aforementioned filter can be adjusted.

[0039] In the above-described embodiment, an example was shown in which the shielding structure was used in an automobile, but the shielding structure can be used not only in automobiles but also in anything that consumes power and performs communication. [Explanation of symbols]

[0040] 1, 1A, 1B, 1C Shielded structure 11 Conductor connection 12. Housing 13, 13B, 13C 1st Shield 15 First insulation section 21 First Wire 22 Second Shield 23 Second insulation section 31 Second Wire 32 Case 41 Third Wire

Claims

1. a conductive shield that covers a conductor that supplies power to an input unit to which power is input in a vehicle; and a connection portion that electrically connects the shield to a conductive housing that covers the input portion; an insulating portion that insulates between the shield and the housing; having A resonant circuit is formed by the inductance component of the shield and the capacitance component of the insulating portion, The frequency of the noise in the vehicle is included in a suppression band that includes the resonant frequency of the resonant circuit. Shielded structure.

2. The shield has an insulating layer provided on at least a part of a surface facing the housing. The shield structure according to claim 1 .

3. The shield structure according to claim 1 , wherein at least one of the shield and the housing comprises a magnetic material.

4. The shield structure according to any one of claims 1 to 3, the conductors include a first conductor connected to an output of the power and a second conductor connected to the input; A conductor connection portion that connects the first conductor and the second conductor is provided. Shielded connector.

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