JP6546404B2 - Coupler and wire harness using the same - Google Patents

Description

  The present invention relates to a coupler and a wire harness using the same.

  There is a coupler for branching a car communication signal. Such couplers may come off due to vibration. Moreover, although there exist crimping etc. in the connection method of such a coupler, at the time of installation, an effort arises.

  Therefore, non-contact couplers are used (see, for example, Non-Patent Document 1). The technology described in Non-Patent Document 1 realizes a noncontact noncontact coupler by utilizing stray capacitance between the cable and the cable to be measured. This noncontact coupler improves the measurement accuracy by changing the capacitance with a relay. Note that various proposals have been made to use a non-contact, that is, a circuit configuration insulated in a direct current manner (see, for example, Patent Document 1).

JP 2008-76337 A

Sato, Kuwahara, “Improvement of measurement accuracy of capacitive voltage probe”, Shingu Technical Report, The Institute of Electronics, Information and Communication Engineers, January 2013, EMCJ 2012-107, p. 31-36

  However, although the technique described in Non-Patent Document 1 improves the measurement accuracy, it does not reduce the influence of external noise while improving the sensitivity. Therefore, even if the car communication signal is branched by the coupler using the technique described in Non-Patent Document 1, the influence of the external noise can not be reduced while improving the sensitivity.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a coupler capable of reducing the influence of extraneous noise while improving sensitivity and a wire harness using the same.

The coupler according to the present invention has an inner conductor provided inside, an inner electrode electrostatically coupled to the inner conductor, and an outer electrode of the inner electrode, and is electrostatically coupled to the inner electrode, and a part is grounded that includes an external electrode, the external electrodes, the electrostatic between to reduce the surface area in comparison with those not the meshed with a plurality of through holes by meshed is formed between the inner electrode It is characterized in that the capacity is reduced .

  According to the coupler of the present invention, the influence of extraneous noise can be reduced while improving the sensitivity.

  In the coupler according to the present invention, the capacitance between the inner electrode and the outer electrode is relatively smaller than the capacitance between the inner electrode and the inner conductor. Is preferred.

  This coupler can improve the gain.

Further, in the coupler according to the present invention, it is preferable that the size of the cross-sectional shape of the external electrode is determined based on the frequency to be cut off included in the external noise that arrives at the external electrode.

According to this coupler, it is possible to cut off the frequency to be cut off included in the external noise coming to the external electrode .

  A wire harness according to the present invention includes the coupler described above.

  ADVANTAGE OF THE INVENTION According to the wire harness which concerns on this invention, the communication signal for vehicles in which the influence of the external noise was reduced can be transmitted correctly.

  According to the coupler of the present invention, the influence of extraneous noise can be reduced while improving the sensitivity. Moreover, according to the wire harness which concerns on this invention, the communication signal for vehicles in which the influence of the external noise was reduced can be transmitted correctly.

FIG. 2 is a view showing an example of a schematic configuration of a coupler according to Embodiment 1; It is a figure which shows an example of the cross-sectional shape of the coupler which follows the A-A 'line | wire of FIG. It is an equivalent circuit schematic of the coupler of FIG. 1, and the measurement part 31. FIG. It is a figure which shows the positional relationship of the internal conductor 11 and the internal electrode 13 in the coupler of FIG. It is a diagram illustrating the influence of external noise gain S _21. FIG. 7 is a diagram for explaining the shift of the gain S ₂₁ according to the proportion of the through holes provided in the external electrode 15. 5 is a view showing an example of the shape of an external electrode 15 according to Embodiment 2. FIG. FIG. 14 is a view showing an example of the shape of an external electrode 15 according to Embodiment 3. FIG. 16 is a view showing an example of an equivalent circuit of an external electrode 15 according to a fourth embodiment. FIG. 18 is a view showing an example of the shape of the external electrode 15 according to Embodiment 5.

Embodiment 1
FIG. 1 is a view showing an example of a schematic configuration of a coupler according to the first embodiment. As shown in FIG. 1, the coupler is provided with an inner electrode 13 and an outer electrode 15, and branches a car communication signal transmitted through the inner conductor 11.

  The inner conductor 11 has a surface coated with an insulating material, and is formed of a highly conductive member such as copper as a member for transmitting a car communication signal, and functions as an object to be measured. is there.

  The internal electrode 13 is provided with the internal conductor 11 inside, and is electrostatically coupled to the internal conductor 11. Specifically, the internal electrode 13 is an electrode formed in a cylindrical shape, and is formed of, for example, a conductor such as aluminum.

  The external electrode 15 is provided outside the internal electrode 13, is electrostatically coupled to the internal electrode 13, and is partially grounded. Specifically, the external electrode 15 is an electrode formed in a cylindrical shape, and is formed of, for example, a conductor such as aluminum.

  In addition, although the case where the internal conductor 11, the internal electrode 13, and the external electrode 15 are arrange | positioned concentrically so that it may mention later is assumed, in FIG. 1, suppose that schematic structure is shown and the detail of the arrangement configuration. Illustration of shall be omitted.

  Next, the positional relationship between the inner conductor 11, the inner electrode 13, and the outer electrode 15 and the structure of the outer electrode 15 will be described with reference to FIG. FIG. 2 is a view showing an example of the cross-sectional shape of the coupler taken along the line A-A 'of FIG. As shown in FIG. 2, the inner conductor 11, the inner electrode 13, and the outer electrode 15 are arranged concentrically. Further, the external electrode 15 is one in which a plurality of through holes are formed. The plurality of through holes formed in the external electrode 15 are realized by mesh processing, for example.

  In other words, the surface area of the external electrode 15 is reduced by the plurality of through holes formed in the external electrode 15.

  In addition, a spacer may be provided between the internal electrode 13 and the external electrode 15, for example. The spacer is for keeping a constant distance between the inner electrode 13 and the outer electrode 15 and is formed of a low dielectric constant member such as plastic. Thus, the spacer is inserted between the internal electrode 13 and the external electrode 15 to suppress an increase in coupling capacitance.

  Assuming such an arrangement configuration, the electrode of the coupler is composed of the internal electrode 13 and the external electrode 15. Among the electrodes of the coupler, the internal electrode 13 is electrically coupled to the internal conductor 11. Among the electrodes of the coupler, the external electrode 15 functions as an electrostatic shield to the outside, and is connected to the ground serving as a potential reference.

Here, when the voltage V _c is generated in the internal conductor 11, an electrostatic voltage between the internal conductor 11 and the internal electrode 13 generates an induced voltage in the internal electrode 13. Such an induced voltage is proportional to the voltage V _c generated in the internal conductor 11. Therefore, if the potential difference between the internal electrode 13 and the external electrode 15 is measured, a voltage proportional to the voltage V _c generated in the internal conductor 11 can be measured.

Therefore, as shown in FIG. 1, a measuring unit 31 is provided to detect a car communication signal which is connected to the internal electrode 13 and transmitted through the internal conductor 11. The measurement unit 31 is partially connected to the internal electrode 13 and the other is grounded. The measuring unit 31 measures a voltage V _c generated in the internal conductor 11, specifically, a voltage V _m proportional to the voltage V _c generated in the internal conductor 11.

Next, the electrical configuration of the coupler and the measurement unit 31 will be described with reference to FIG. FIG. 3 is an equivalent circuit diagram of the coupler and the measurement unit 31 of FIG. The voltage V _c is the voltage of the object to be measured generated in the internal conductor 11. The capacitance C _i is a capacitance due to electrostatic coupling between the inner conductor 11 and the inner electrode 13. The capacitance C _s is a capacitance due to electrostatic coupling between the inner electrode 13 and the outer electrode 15. The stray capacitance _Cp is the stray capacitance (floating capacitance of the circuit board and the coaxial cable routing) of the entire measurement system. The resistance R _p is a resistance of the measurement unit 31 and is an input impedance of the measurement unit 31. The voltage V _m is an output voltage of the measurement unit 31 and is a voltage proportional to the voltage V _c generated in the internal conductor 11.

As shown in FIG. 3, the equivalent circuit of the inner conductor 11, the inner electrode 13, and the outer electrode 15 is configured by a series circuit of electrostatic capacitance C _i and electrostatic capacitance C _s . The capacitance C _s and the stray capacitance C _p constitute a parallel circuit. Further, the equivalent circuit of the measuring unit 31 is intended to be configured and the stray capacitance C _p, the parallel circuit of a resistor R _p.

From the equivalent circuit shown in FIG. 3, the relationship between the voltage V _c and the voltage V _m can be obtained by the following equation (1).

  Here, ω is an angular frequency. Moreover, in the frequency range in which following Formula (2) is materialized, Formula (1) is represented by Formula (3).

Equation (3) holds regardless of the frequency. Therefore, in the frequency range in which the equation (2) holds, as shown in the equation (3), the voltage V _m of the measuring unit 31 exhibits a flat characteristic, and as a whole, a constant sensitivity is obtained regardless of the frequency. It is

Also, the gain S ₂₁ are those which can be obtained and the voltage V _m, the ratio of the voltage V _c, the one represented by the formula (4). Gain S _21, of S parameters of the frequency characteristic shows the forward transmission characteristic.

Here, in order to improve the sensitivity, it is necessary to increase the gain S _21. To improve the gain _{S 21,} as shown in equation (4), it is necessary to bring the gain _{S 21} to 0. In order to make the gain S ₂₁ close to 0, it is necessary to make the ratio between the voltage V _m and the voltage V _c close to 1 as shown in the equation (3). Specifically, the electrostatic capacitance C _i can be made relatively large by making the electrostatic capacitance C _s relatively smaller than the electrostatic capacitance C _i , so the voltage V _m and the voltage V _c can be relatively large. Ratio can be made close to one.

Therefore, in order to obtain the equivalent circuit of equation (3), it is necessary to obtain the capacitance C _i and the capacitance C _s . First, it is assumed that the electrode length is sufficiently longer than the radius of the cylindrical electrode formed of the inner electrode 13 and the outer electrode 15. Next, each parameter of the cylindrical electrode will be described with reference to FIG. FIG. 4 is a view showing the positional relationship between the inner conductor 11 and the inner electrode 13 in the coupler of FIG.

  As shown in FIG. 4, in the double cylinder, the radius of the inner cylinder is a, the radius of the outer cylinder is b, and the distance between the center of the inner cylinder and the center of the outer cylinder is d. In the case of (1), the coupling capacity per unit length is determined by Next, the total coupling capacity can be determined by multiplying the coupling capacity determined by the following equation (5) by the electrode length.

The equation (5) is an operation based on the conformal mapping method, which obtains the capacitance of the double cylinder. If d is 0, the centers of the double cylinders coincide with each other, so the capacitance C _s can be obtained.

  Here, since S indicates the area per unit length, the electrode length, specifically, the length of the shape of the internal electrode 13 and the external electrode 15 in the longitudinal direction is given in the calculation result of the equation (5). You need to wear it.

More specifically, as the through hole is formed in the external electrode 15, the surface area of the external electrode 15 is reduced, and hence the size of S in the equation (5) is reduced. As a result, the magnitude of S is smaller than that shown in equation (5). Further, according to Equation (5), as the magnitude of S decreases, the capacitance C _s also decreases. Therefore, as the surface area of the external electrode 15 is reduced, the capacitance C _s can be reduced.

According to the equation (4), if the capacitance C _s is made relatively small, the capacitance C _i can be made relatively large. Therefore, it is possible to approximate the ratio between the voltage V _m and voltage V _c to 1, it is possible to make the gain S ₂₁ to 0. Accordingly, it is possible to improve the gain S _21, it is possible to improve the sensitivity.

In other words, that the plurality of through holes are formed in the external electrode 15 described above means that the capacitance C _s between the internal electrode 13 and the external electrode 15 is the internal electrode 13, and It corresponds to being relatively smaller than the electrostatic capacitance C _i between the internal conductor 11 and the internal conductor 11. That is, the sensitivity characteristics of the coupler depend on the shape of the external electrode 15.

  However, depending on the size, the shape, and the number of the through holes formed in the external electrode 15, the external noise may not be cut off. Therefore, the shape of the external electrode 15 is determined based on the frequency to be cut off so that the frequency to be cut off can be cut off in the assumed external noise.

  Specifically, the frequency at which the external electrode 15 should cut off, that is, the cut-off frequency is considered on the same principle as the waveguide. For example, in the case of a waveguide whose cross-sectional shape is rectangular, the cutoff frequency can be expressed by the following equation (6).

  Here, n and m are 0 or more, and indicate the number of modes. Moreover, a and b shall show the length of the wall surface of a waveguide.

In the case of a waveguide having a circular cross-sectional shape, the cutoff frequency of the TM ₀₁ mode, that is, the monopole mode can be represented by the following equation (7).

Here, r represents the radius of the waveguide. Further, χ ₀₁ indicates the solution of the first-order Bessel function of the first kind J ₀ (r).

Further, in the case of a waveguide whose cross-sectional shape is a square, the cutoff wavelength λ _c when transmitting the TE _mn wave can be expressed by the following equation (8).

Here, in the equation (8), the relative permittivity of the medium in the tube is ε _r , the relative permeability is μ _r , the length of the long side of the waveguide is a [m], and the short side of the waveguide The length is indicated by b [m] respectively.

  By using any one of the above formulas (6) to (8), the shape of the external electrode 15 can be determined based on the cut-off frequency. As a result, the external electrode 15 whose shape has been determined shuts off external noise below the cutoff frequency.

Next, the characteristics of the coupler having the above configuration will be described using FIGS. 5 and 6. Figure 5 is a diagram illustrating the influence of external noise gain S _21. In FIG. 5, the influence of extraneous noise due to a conventional coupler is shown by a broken line, and the effect of extraneous noise of the coupler according to the present embodiment is shown as a solid line. In particular, in the conventional coupler, when the frequency of the external noise is 100 MHz or less, the influence of the external noise is large. On the other hand, in the coupler according to the present embodiment, even when the frequency of the external noise is 100 MHz or less, the influence of the external noise is reduced. This also indicates that the coupler according to this embodiment can reduce the influence of extraneous noise.

Figure 6 is a diagram for explaining the transition of gain S ₂₁ in accordance with the proportion of through holes provided in the external electrodes 15. As shown in FIG. 6, as the proportion of provided holes increases to the external electrodes 15, i.e. as the ratio of the surface area of the external electrode 15 is small, the gain S ₂₁ is improved. This also by reducing the surface area of the external electrodes 15, that can improve the gain S ₂₁ shown.

  From the above description, according to the coupler of the first embodiment, the influence of external noise can be reduced while improving the sensitivity. Further, the coupler according to the first embodiment can reduce the influence of external noise while improving the sensitivity, and therefore, if it is a wire harness including such a coupler, a vehicle communication signal in which the influence of the external noise is reduced is used. It can be transmitted accurately.

Embodiment 2
FIG. 7 is a view showing an example of the shape of the external electrode 15 according to the second embodiment. In the second embodiment, the configurations and functions of the inner conductor 11, the inner electrode 13, and the measuring unit 31 are the same as in the first embodiment. In the second embodiment, the description of the same configuration and function as those of the first embodiment will be omitted. In the second embodiment, the shape of the external electrode 15 is different from that of the first embodiment.

  As shown in FIG. 7, the shape of the external electrode 15 is spiral processed. Thus, the external electrode 15 is spiral-processed to form a spiral shape. With such a configuration, the external noise that comes in can be blocked while reducing the surface area of the external electrode 15. Thereby, the influence of extraneous noise can be reduced particularly remarkably.

  From the above description, according to the coupler according to the second embodiment, the influence of the external noise can be particularly remarkably reduced by making the shape of the external electrode 15 a spiral shape.

Embodiment 3
FIG. 8 is a view showing an example of the shape of the external electrode 15 according to the third embodiment. In the third embodiment, the configurations and functions of the inner conductor 11, the inner electrode 13, and the measuring unit 31 are the same as in the first and second embodiments. In the third embodiment, the description of the configurations and functions similar to those of the first and second embodiments will be omitted. In the third embodiment, the shape of the external electrode 15 is different from the first and second embodiments.

  As shown in FIG. 8, the shape of the external electrode 15 is W spiral processed. As described above, the external electrode 15 is subjected to W spiral processing to form a W spiral shape, so that the surface area of the external electrode 15 is increased as compared with the case where the external electrode 15 is formed into a spiral shape, but the external noise is further blocked. . Thereby, the influence of the external noise can be reduced particularly remarkably as compared with the case of the spiral shape.

  From the above description, according to the coupler according to the third embodiment, by making the shape of the external electrode 15 a W spiral shape, the influence of extraneous noise can be particularly remarkably reduced as compared to the case where the outer electrode 15 is made a spiral shape. it can.

Embodiment 4
FIG. 9 is a view showing an example of an equivalent circuit of the external electrode 15 according to the fourth embodiment. In the fourth embodiment, the configurations and functions of the inner conductor 11, the inner electrode 13, and the measuring unit 31 are the same as in the first to third embodiments. In the fourth embodiment, the configuration and function of the external electrode 15 are the same as in the second and third embodiments. In the fourth embodiment, the description of the same configuration and function as those of the first to third embodiments will be omitted. In the fourth embodiment, on the premise of the shape of the external electrode 15 in any one of the second and third embodiments, a configuration in which a resonance frequency is further assumed will be described.

  If the shape of the external electrode 15 is a spiral shape or a W spiral shape, the external electrode 15 can be shown by an equivalent circuit as shown in FIG. In this case, the resonant frequency is expressed by the following equation (9).

  Since the equivalent circuit of FIG. 9 is a parallel circuit, it is possible to remove external noise including a frequency component that becomes a resonant frequency inside the shape.

  From the above description, according to the coupler of the fourth embodiment, it is possible to remove extraneous noise including a frequency component that becomes a resonance frequency.

Embodiment 5
In the fifth embodiment, the configurations and functions of the inner conductor 11, the inner electrode 13, and the measuring unit 31 are the same as in the first to fourth embodiments. In the fifth embodiment, the description of the configurations and functions similar to those of the first to fourth embodiments will be omitted. In the fifth embodiment, the shape of the external electrode 15 is different from the first to fourth embodiments. Therefore, the shape of the external electrode 15 will be described with reference to FIG.

  FIG. 10 is a view showing an example of the shape of the external electrode 15 according to the fifth embodiment. As shown in FIG. 10, since the external electrode 15 is formed in a louver shape, the angle of the louver can be appropriately adjusted.

  For example, as shown in FIG. 10, the surface area of the external electrode 15 when looking at the louver from the B side and the surface area of the external electrode 15 when looking at the louver from the B ′ side are different. Specifically, the angle of the louver is smaller in the case of the B 'side than in the case of the B side when the lower side of the drawing sheet is used as a reference. When the lower side of the drawing sheet is used as a reference, the surface area of the external electrode 15 becomes larger as the angle of the louver is smaller. Thus, the surface area of the external electrode 15 is changed by adjusting the angle of the louver.

  That is, when the lower side of the drawing sheet is used as a reference, the surface area of the external electrode 15 decreases as the louver angle increases. On the other hand, the surface area of the external electrode 15 increases as the louver angle decreases. When the angle of the louver exceeds 90 degrees on the basis of the lower side of the drawing, the surface area of the external electrode 15 is increased.

  In other words, when the angle of the louver is an acute angle based on the lower side of the drawing, the surface area of the external electrode 15 decreases as the angle of the louver increases. On the other hand, if the angle of the louver is an obtuse angle with the lower side of the drawing as a reference, the surface area of the external electrode 15 becomes larger as the angle of the louver becomes larger.

From the above description, according to the coupler of the fifth embodiment, when the external electrode 15 is formed in a louver shape, the surface area of the external electrode 15 can be changed by adjusting the angle of the louver. This makes it possible to change the gain _{S 21.}

  From the above description, in the coupler according to the first to fifth embodiments, the internal electrode 13 is provided with the internal conductor 11 inside, and is electrostatically coupled to the internal conductor 11. The external electrode 15 is provided outside the internal electrode 13 and is electrostatically coupled to the internal electrode 13, and a part of the external electrode 15 is grounded. As described above, the coupler has a double structure of the internal electrode 13 and the external electrode 15, and a part of the external electrode 15 is grounded. This makes it possible to avoid the influence of stray capacitance between the outside of the coupler and the coupler. Thus, the influence of extraneous noise can be reduced.

  Further, the shape of the external electrode 15 is determined based on the frequency at which the external electrode 15 should be cut off. Thus, the external electrode 15 can cut off the frequency to be cut off. Therefore, if the frequency to be cut off is determined from the frequency included in the frequency component of the extraneous noise, the influence of the extraneous noise can be particularly significantly reduced.

Further, the external electrode 15 is one in which a plurality of through holes are formed. Such an arrangement, the inner electrode 13, the electrostatic capacitance C _s between the external electrodes 15, and the internal electrode 13 is relatively smaller than the capacitance C _i between the inner conductor 11 Is equivalent to Therefore, it is possible to approximate the voltage V _m can be detected by the coupler, the ratio of the voltage V _c inputted to the coupler 1. Thus, since the gain _{S 21} can be brought close to zero, it is possible to improve the gain _{S 21.} As a result, the sensitivity of the coupler can be improved.

  Therefore, the coupler according to the present embodiment can reduce the influence of external noise while improving the sensitivity. In addition, since the coupler can reduce the influence of external noise while improving the sensitivity, in the case of a wire harness including such a coupler, it is necessary to accurately transmit a vehicle communication signal in which the influence of the external noise is reduced. Can.

  Thus, according to the coupler according to the first to fifth embodiments, the internal conductor 11 is provided inside, the internal electrode 13 electrostatically coupled to the internal conductor 11, and the internal electrode 13 are provided outside An external electrode 15 electrostatically coupled to the electrode 13 and partially grounded is provided, and the external electrode 15 has a plurality of through holes formed therein. Therefore, the influence of extraneous noise can be reduced while improving the sensitivity.

Further, in the coupler according to the first to fifth embodiments, the electrostatic capacitance C _s between the internal electrode 13 and the external electrode 15 is compared with the electrostatic capacitance C _i between the internal electrode 13 and the internal conductor 11 Preferably relatively small. Therefore, it is possible to improve the gain _{S 21.}

  Moreover, in the coupler according to the first to fifth embodiments, the shape of the external electrode 15 is preferably determined based on the frequency at which the external electrode 15 should cut off. Thus, the frequency to be cut off can be cut off.

  Moreover, in Embodiments 1 to 5, it is preferable to include the coupler described above. Therefore, the vehicle communication signal in which the influence of the external noise is reduced can be accurately transmitted.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to the said embodiment, You may add a change in the range which does not deviate from the meaning of this invention.

  For example, in the present embodiment, an example in which the cross-sectional shape of the coupler formed of the internal electrode 13 and the external electrode 15 is circular has been described, but the present invention is not limited thereto. It may be the case. If the cross-sectional shape of the coupler is rectangular, the shape assuming the frequency to be cut off may be determined based on the equation (6) described above. Further, when the cross-sectional shape of the coupler is a square, the shape assuming the frequency to be cut off may be determined based on the equation (8) described above.

Further, the coupler described above may be configured as a switch by using it under the condition that the gain S ₂₁ changes extremely. Specifically, it may be incorporated into a configuration such as a car engine switch and a door lock. Further, as a condition for the gain S ₂₁ greatly differs, may be embedded in the charging connector for an electric vehicle. Further, as a condition for the gain S ₂₁ greatly differs, it may be used as a transmission member for non-contact power feeding.

11: internal conductor 13: internal electrode 15: external electrode 31: measurement unit

Claims (4)

An inner electrode provided with an inner conductor and electrostatically coupled to the inner conductor;
An external electrode provided outside the internal electrode, electrostatically coupled to the internal electrode, and partially grounded;
Equipped with
The external electrode has a surface area smaller than that of the non- mesh-processed one by making a plurality of through holes formed by mesh processing, thereby reducing the capacitance with the internal electrode. Coupler characterized by   The electrostatic capacitance between the internal electrode and the external electrode is relatively smaller than the electrostatic capacitance between the internal electrode and the internal conductor. The coupler according to 1. The coupler according to claim 1 or 2, wherein the size of the cross-sectional shape of the external electrode is determined based on the frequency to be shut off included in the external noise that arrives at the external electrode.   A wire harness comprising the coupler according to any one of claims 1 to 3.