JPH09199237A - Shielded cable with connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance a noise elimination effect by covering a filter unit provided on a board through which plural contact elements pass, a group of insulated conductors, and a shield case with a shielding case. SOLUTION: Plural contact elements 1 are arranged so as to pass through a board 2 on which filter units 3 composed of electrodes 3A directly contacting the contact elements 1, insulation separators 3B, and grounding electrodes 3c are formed, and one side ends 1A of the contact elements 1 and the insulated conductors 5 of a cable 4 are electrically connected. In the cable 4, the outer periphery of the insulated conductors 5 are surrounded by a pressing winding 4A, a shielding layer 6, and a sheath 4B, and a rubber bushing 8 is arranged on the mechanical coupling portion of the shielding case 7 of a connector and the cable 4. The shielding case 7 and the shielding layer 6 of the cable 4 are electrically joined at a rubber bush 8 portion. The shielding case 7 is divided into a front housing 7A and a buck housing 7B so as to fix the board 2 as sandwiching the same from both sides.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shielded cable with a connector in which a connector having a high shielding effect is integrated with a terminal portion.

[0002]

2. Description of the Related Art In recent years, with the miniaturization, high performance, and high speed operation of various electronic devices, electronic devices such as computer devices, printer devices, modem devices, OA devices, and FA devices have been equipped with these devices. It is required to use a data link cable having a high shielding effect for data transmission between internal wiring and devices and equipment. As a result, the reliability of the transmission signal is ensured, noise is prevented from invading from other devices, and unnecessary noise is prevented from occurring in other devices. In particular, this noise countermeasure is called so-called EMI countermeasure,
It is listed in the items required as the basic performance of this type of device.

As a countermeasure against such noise, conventionally, a data link cable having the following structure has been proposed. For example, Japanese Unexamined Patent Publication No. 61-165972 discloses an interface bus cable device including a multicore cable in which a plurality of core wires are covered with a shield braided wire and a shielding member. This uses the braided wire shield end of the cable to enhance the shielding effect inside the connector. Further, Japanese Utility Model Laid-Open No. 61-76626 discloses an interface cable in which a connector is connected to both ends of a cable body near the connector and a ferrite core is attached to the cable near the connector. This is because the cable is configured to pass through the ferrite core, so that the impedance with respect to noise having a high frequency component in the transmission signal of the cable is increased and the noise is removed.

Further, Japanese Utility Model Laid-Open No. 3-130114 discloses a multi-core cable in which a plurality of core wires are covered with a shield braided wire, and a magnetic material through which the core wires of the multi-core cable penetrate in a metal hood for a connector. The arranged signal cables are introduced. In this cable, a magnetic material core is attached to each core wire to prevent high-frequency components of noise flowing in the core wire. Further, Japanese Patent Laid-Open No. 64-89107 introduces a wire harness with a noise prevention device, which is a relay means of a wire harness in which a feedthrough capacitor is attached to each terminal of a relay connector. This is to use a feedthrough capacitor of a relay connector to ground the conductors of the cable via the capacitors and to remove high frequency components of noise transmitted in the cable.

[0005]

The conventional noise suppression cable as described above has the following problems to be solved. In order to enhance the shielding effect of the cable with the connector, it is preferable to use a shielded cable for the cable and also shield the connector itself with a shield case made of a conductor. However, when a magnetic material is arranged such that each core wire penetrates inside the connector, a large number of magnetic material cores are densely packed inside the connector, and the electrical insulation characteristics between the core wires and between the core wire and the shielding case are deteriorated. Further, if the distance is widened in order to improve the insulating property, the shielding case becomes large. On the other hand, if a ferrite core is attached to the cable outside of such a connector, or if a connector for relay is provided, the number of accessories of the cable increases, the whole size increases, and the overall cost of the cable with connector increases. Becomes It should be noted that simply using a shielded cable and a shield case for the connector does not necessarily eliminate the high frequency components of the noise transmitted through the cable, and it becomes difficult to meet the requirements for noise countermeasures that will become more severe in the future.

In order to solve the above-mentioned object, it is an object of the present invention to provide a shielded cable with a connector, which is excellent in noise elimination characteristics, using a filter unit, a shielded cable and a shielding case.

[0007]

The shielded cable with a connector of the present invention adopts the following configuration. <Structure 1> A substrate through which a plurality of contact elements penetrate, a filter unit formed of a filter element group integrally formed on the substrate and provided for each of the contact elements, and the plurality of contact elements. A shielded cable having a core wire group electrically connecting terminals to each other, and a shield layer surrounding the outer periphery thereof, and a plurality of contact elements, a substrate, and a core wire group terminal electrically connected to the shield layer of the shielded cable. A shielded cable with a connector, comprising:

<Explanation> As shown in FIGS. 1 (a) to 1 (c), a plurality of contact elements 1 are for electrically connecting a core wire 5 of a shielded cable 4 and a connector or the like of a device (not shown). Is. The contact element 1 is arranged so as to pass through the substrate 2, one end of which is electrically connected to the core wire 5 of the shielded cable 4 and the other end of which is electrically connected to a device connector or the like. The shape may be any configuration such as a pin shape or a plate shape. The filter element is a capacitor,
It is composed of a resistor and / or a magnetic element. In the case of a capacitor, one end of the electrode is electrically connected to the contact element 1 and the other end is grounded. This is to bypass the high frequency component flowing in the contact element 1. In the case of a resistor, the inductance of the resistor blocks the passage of high frequency components. The magnetic element is made of, for example, a magnetic ring formed on the substrate by thick film printing or the like, and penetrates the contact element 1 to block high frequency components. In addition,
For example, if a capacitor is formed on one surface of the substrate and a magnetic element is formed on the other surface or the through hole to form a composite filter, the noise removal effect is further enhanced. By these, the noise component in the transmission signal flowing through the contact element 1 is blocked and absorbed by the filter unit 3,
Noise in the high frequency region is removed from the transmission signal.

The filter unit 3 integrally formed on the substrate 2 is used because the surface of the substrate is smooth and there are no unnecessary protrusions inside the shielding case 7, and the electric field inside the shielding case 7 is not present. This is because the shielding effect is enhanced by making the uniform. As a method of integrating the filter unit 3 with the substrate 2, for example, a laminated structure by a thick film method is suitable. In addition,
The unevenness that slightly increases or decreases the thickness of the substrate does not impair the smoothness. This is because there is no substantial adverse effect on the shielding effect. If there are no unnecessary protrusions inside the connector, a sufficient insulation distance is secured between the contact elements 1 and between each contact element 1 and the shielding case 7, and a compact connector with good insulation characteristics is provided. realizable. Such an effect is remarkable when the shield case 7 is made of a conductor.

The shielded cable 4 is composed of, for example, a multi-core cable in which a shield layer 6 is formed immediately below the sheath 4B of two or more mutually insulated core wires 5.
The shielding layer 6 surrounds the core wires 5 and collectively shields them from electricity, and is made of a good electrical conductor. This may have any structure such as a braided wire of copper or aluminum, a laminated tape in which an aluminum-polyester composite film is laminated, a tape winding layer of copper or aluminum, or the like. Alternatively, a shielded cable having a structure in which a flat cable having a flat cable cross section is shielded may be used. Further, the shape of the connector is arbitrary and may be configured according to the cross-sectional shape of the cable.

<Structure 2> In Structure 1, the filter unit is made of at least one of a capacitor, a resistor, and a magnetic material element and is formed on a substrate by a printing method.

<Explanation> The filter unit may be a capacitor, a resistor, a magnetic element, or a single unit, or may be formed by selecting any two or more of them on a substrate and using them in combination. Good. The connection method is based on a well-known circuit configuration that blocks the propagation of noise components or bypasses them. The reason why the printing method is employed is that thin, flat, and uniform characteristics can be efficiently produced.

<Structure 3> In Structure 2, the filter unit comprises a capacitor formed by laminating an electrode formed on the substrate and electrically connected to each of the contact elements, an insulating separator layer, and a ground electrode. Shielded cable with connector.

<Description> Each contact element 1 is grounded by the filter unit 3 via a capacitor having a predetermined electrostatic capacity. Preferably, as shown in FIG. 1B, an electrode 3A electrically connected to each contact element 1
Then, the insulating separator layer 3B and the ground electrode 3C are sequentially laminated to form a capacitor. As a result, the high frequency component in the transmission signal flowing through the contact element flows back to the shielding case 7 and the shielding layer 6 of the cable through the filter unit 3, and the noise in the high frequency region is removed from the transmission signal. The capacitor may be formed by stacking the electrode 3A and the ground electrode 3C in the reverse order.

As described above, when the filter unit 3 is composed of a capacitor group, it is the smallest in size as compared with a magnetic ring or the like, and enables effective noise removal. Preferably, the ground electrode 3C covers almost the entire surface of the substrate 2. This is because the inductance of the ground electrode is made as small as possible to improve the wraparound of noise and the like between the contact elements. Further, it is to enhance the shielding effect of the portion of the substrate 2 made of an insulator. The reason why it is almost the entire surface is that the ground electrode is not formed in the portion where the contact element 1 penetrates. That is, since the connection portion between the contact element 1 and the core wire 5 is almost completely isolated from the outside by the ground electrode 3C of the substrate 2 and the shielding case 7, noise to be removed does not penetrate the substrate or the like and leaks to the device side. .

<Structure 4> In Structure 3, the insulating separator is formed by thick film printing of a perovskite type dielectric, and the electrostatic capacitance between the electrode electrically connected to each contact element and the ground electrode is 22. A shielded cable with a connector, which is selected in the range of up to 22,000 pF.

<Description> When a perovskite type dielectric is formed by thick film printing, a substrate-integrated filter of this type can be manufactured at a relatively low temperature with a small size and high performance. That is, due to the structure of the data link cable, the size of the connector is limited, and the contact elements 1 are arranged at narrow intervals. This dielectric is practically optimal for forming a capacitor having a sufficient capacity there. Capacitance up to 22,000pF
The reason is that if the capacitance is larger than this, the reactance becomes lower than the original transmission signal and the transmission signal passes through this capacitor. Also, the reason why the minimum value is 22 pF is that the reactance with respect to harmful noise becomes high and the noise cannot be sufficiently removed below this. More preferably, 22 to 10,0
It is 00 pF.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to specific examples. <Specific Example> FIG. 1A is an exploded perspective view of a shielded cable with a connector of the present invention. 1B is a sectional view of the substrate taken along the line AA in FIG. 1A, and FIG. 1C is an arrow B.
FIG. 6 is a cross-sectional view of the connector portion taken along the line B. As shown in this figure, the shielded cable with a connector of the present invention is
A plurality of contact elements 1 are arranged so as to penetrate the substrate 2, and these and the core wire 5 of the cable 4 are electrically connected to each other. The substrate 2 is shown in FIG.
The filter unit 3 including a capacitor element as shown in (b) is formed by, for example, a thick film printing method.

The filter unit 3 is composed of an electrode 3A formed so as to be in direct contact with the contact element 1 penetrating the substrate 2, an insulating separator layer 3B laminated on the electrode 3A, and a ground electrode 3C. It This substrate 2
As the substrate, a 96% alumina ceramic substrate is used. In addition, an Ag-Pt-based conductive paste (D9516: manufactured by ESL) is used for the electrode 3A, and thick film printing is used for the portion including the inner surface of the through hole into which the contact element 1 of the substrate 2 is inserted and its vicinity. It was formed. The insulating separator layer 3B is made of a dielectric paste [Pb (Mg _1/3
Nb _2/3 ) O ₃ : PbTiO ₃ = 40: 1 mol] is formed by thick film printing, drying and firing. The dielectric paste may be printed once or several times depending on the desired design. The capacitance of the capacitor element is selected depending on the area. The ground electrode 3C is formed on almost the entire area of the substrate 2 by Ag-.
The Pt-based conductive paste is thick-film printed, dried and fired. In order to protect them, a glass protection paste (not shown) is thick-film printed, dried, and baked on the upper side to protect the upper surface of the substrate 2.

The contact element 1 is made of a silver-plated copper rod, is inserted into a through hole of the substrate 2 and is soldered to the electrode 3A, and the conductor of the core wire 5 shown in FIG. It is attached. The contact element may be inserted through the substrate in a direction in which 1A and 1B are opposite to those shown in (b). The other end 1B is electrically connected to a female contact of a device (not shown). In this example, a D-sub type rectangular connector which is widely used for computer data links is illustrated.
Further, as shown in (c) of the figure, the cable 4 has a core wire 5
The outer circumference is surrounded by the press winding 4A, the shielding layer 6 and the sheath 4B. A rubber bush 8 is arranged at a portion where the shield case 7 of the connector and the cable 4 are mechanically coupled to each other to provide mechanical protection from bending. In addition, in order to improve the shielding characteristics and prevent the enlargement of the shielding case 7, which is the object of the present invention, and further improve the insulating characteristics, the shielding case 7 and the shielding layer 6 of the cable 4 are made of the rubber bush 8. Electrically connected in parts, shielding case 7
It doesn't stick out inside.

The core wire 5 is electrically connected to the contact element 1 by soldering. The filter unit 3 as described using (b) is formed on the substrate 2, but as shown in this cross-sectional view, the filter unit 3 is substantially flat as a whole and has a large protrusion inside the shielding case 7. Not formed. That is, as a result, the core wire 5 is orderly and electrically connected to the contact element 1 inside the shielding case 7, and a sufficient space is secured. As shown in (a), the shielding case 7 is divided into a front housing 7A and a back housing 7B for fixing the substrate 2 by sandwiching it from both sides. These are connected to each other by screws (not shown) or the like, and are configured to protect the connection portion between the contact element 1 and the core wire 5. This substrate is sandwiched from both sides by a reinforcing plastic plate 15 arranged on the back housing 7B side and a metallic fixing plate 16 arranged on the front housing 7A side, as shown in (c). While being reinforced, the ground electrode 3C is electrically connected to the shielding case via the fixing plate 16.

FIG. 2 shows a side view of the shielded cable with a connector of the present invention. As shown in this figure, the shielded cable with a connector of the present invention is provided with connectors 11 and 12, for example, at both ends thereof. Then, in this example, all the connectors are covered with the shielding case 7 having the above-described configuration, and are effectively shielded. For a multi-branch cable for actions such as Y-branching and X-branching, a shield case can be used for any connector. Of course, the shielding effect is the highest when the shielding case is used for all the connectors.

FIG. 3 is a perspective view of a main part of a connector-equipped cable having another structure for comparison with the shielded cable with a connector of the present invention shown in FIG. As shown in this figure, it is also possible to accommodate, for example, the core wire 5 to which the ferrite core 13 is attached inside the shielding case 7 shown in FIG. 1 and electrically connect to each contact element 1.

However, in this case, the ferrite cores 13 reduce the gaps between the core wires 5 and deteriorate the insulation characteristics. Further, as shown in (b) of the figure, due to the presence of the ferrite core 13, the shielding case 7
The gap between and becomes short, and the insulation characteristics deteriorate. That is,
When a predetermined high voltage is applied, the breakdown voltage when dielectric breakdown occurs between the two decreases. Therefore, in order to obtain a breakdown voltage above a certain level, the shielding case 7 must be upsized. On the other hand, in the shielded cable with a connector of the present invention as shown in FIG. 1, such a large protrusion does not exist inside the shielding case 7, a sufficient gap can be secured, and the connector can be downsized. Good shielding properties are obtained.

Here, in order to clarify the noise shielding effect of the shielded cable with a connector of the present invention, the following test was conducted. FIG. 4 shows a plan view of a cable shielding characteristic test device. In this device, a shielded cable 4 with a connector according to the present invention having shield cases 7 attached to both ends is arranged on a turntable 21, and a predetermined signal is input from one end of the shielded cable 4 while a 50Ω terminator 22 is provided at the other end. Is terminated with. And turntable 2
While rotating 1, the noise radiated toward the air from this shielded cable with a connector is received by using the antenna 23 arranged at a position 3 meters away from this.

FIG. 5 is a side view of this characteristic test apparatus. As shown in this figure, the antenna 23 is supported on the support column 24 at a height of 2 meters above the ground. Moreover, the upper surface of the turntable 21 is set at a position 1 meter from the floor surface. The antenna 23 is connected to an amplifier 26 via a coaxial cable 25, and a signal received by the antenna 23 is amplified by the amplifier 26, analyzed by a spectrum analyzer 27, and a plotter 28.
It is configured to be printed out by using. Note that the characteristics when noise is emitted from the shielded cable with connector 4 to the outside and the characteristics when noise enters the shielded cable with connector 4 from the outside have a front and back integral relationship, and are almost equal. Then, we show the effect by measuring only the characteristics when it is radiated to the outside.

FIG. 6 shows the noise cutoff characteristic data of the comparative example, and FIG. 7 shows the noise cutoff characteristic data according to the present invention. In the graphs shown in FIGS. 6 and 7, the vertical axis represents the signal level in [dB] (decibel), and the signal level increases from the bottom to the top of the graph. 1 scale is 10
dB. The horizontal axis indicates the signal frequency. One scale is 100 MHz, and the frequency band was measured for all frequencies up to 1000 MHz. A square wave of 50 nsec was supplied to this cable as noise. In this case, the comparative example shown in FIG. 6 is the noise cutoff characteristic in the case where the connector not using the filter unit and the shielded cable are used, and relatively high noise is radiated over all frequencies.

On the other hand, as can be seen from the data according to the present invention shown in FIG. 7, when the above filter unit is used, the noise level is sufficiently lowered as a whole, and extremely good characteristics are exhibited.

[0029]

INDUSTRIAL APPLICABILITY The shielded cable with a connector of the present invention provides excellent effects in EMI countermeasures, noise countermeasures, etc. when used in a data link of electric equipment, information processing equipment and the like. Further, the substrate 2 can be manufactured at a low cost by using the thick film method or the like, and the shielding case or the like is sufficiently smaller than that of the comparative example, so that the cost can be reduced as a whole as a whole. it can. Therefore, it is possible to provide a low-cost shielded cable with a connector that has excellent shielding characteristics and pressure resistance characteristics, high reliability, high productivity, and the like.

[Brief description of drawings]

FIG. 1A is an exploded perspective view of a shielded cable with a connector of the present invention, FIG. 1B is a sectional view of a portion including a contact element taken along the line AA, and FIG. It is sectional drawing of the part seen from the BB cross section of a case.

FIG. 2 is a side view of the shielded cable with a connector of the present invention.

3A and 3B are perspective views of a main part of a comparative example.

FIG. 4 is a plan view of a characteristic test device.

FIG. 5 is a side view of a characteristic testing device.

FIG. 6 is noise cutoff characteristic data when a connector and a shielded cable that do not use the filter unit of the comparative example are used.

FIG. 7 is noise cutoff characteristic data according to the present invention.

[Explanation of symbols]

 1 Contact Element 2 Substrate 3 Filter Unit 4 Shielded Cable 5 Core Wire 6 Shielding Layer 7 Shielding Case

Claims (4)

[Claims] 1. A substrate through which a plurality of contact elements penetrate, a filter unit formed of a filter element group integrally formed on the substrate and provided corresponding to each of the contact elements, and the plurality of contacts. A shielded cable having a core wire group for electrically connecting terminals to the elements and a shield layer surrounding the outer periphery thereof, and a plurality of contact elements, the substrate and the core wire group electrically connected to the shield layer of the shield cable. A shielded cable with a connector, comprising: a shield case made of a conductor that surrounds a terminal. 2. The shielded cable with a connector according to claim 1, wherein the filter unit is made of at least one of a capacitor, a resistor, and a magnetic element formed on a substrate by a printing method. 3. The filter unit according to claim 2, wherein the filter unit comprises a capacitor formed by stacking an electrode formed on a substrate and electrically connected to each of the contact elements, an insulating separator layer, and a ground electrode. Shielded cable with connector. 4. The insulating separator according to claim 2, wherein the insulating separator is formed by thick film printing of a perovskite type dielectric, and the capacitance between the electrode electrically connected to each contact element and the ground electrode is A shielded cable with a connector, which is selected in the range of 22 to 22,000 pF.