JPH06132054A - Connector for cable - Google Patents

Abstract

PURPOSE:To obtain a connector for a cable with which electromagnetic interference generated from a cable can be efficiently reduced at a low price. CONSTITUTION:The shield member 13 of a cable 14 for an interface is mounted on the case 22 of a connector on the bottoms side with a hardware 21 for holding down the shield member 13. A group 11 of lines for a signal is connected with a metal shell 15 through the recessed part of two plates 32 of ferrite. Since the group 11 of lines for a signal is surrounded with the two plates 32 of ferrite, electromagnetic interference can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable connector for reducing electromagnetic interference waves generated from electronic circuits or electric circuits.

[0002]

2. Description of the Related Art An electromagnetic interference wave generated from an electronic circuit or the like causes a malfunction in another electronic circuit or the like, or causes noise in a radio or a television. For this reason, conventionally, measures have been taken to reduce the influence of such electromagnetic interference waves on the periphery of equipment.

Typical of these are ferrite cores and ferrite cores that have lead wires themselves.
There is a method of soldering beads on a printed wiring board.
By suppressing the current change of the signal flowing through each lead wire by such a method, the generated electromagnetic interference wave is reduced.

However, in the case of an interface connecting a digital computer and its peripherals, if the current change of a high frequency digital signal is suppressed to a certain amount or more, the voltage waveforms of these signals will be destroyed. As a result, the operation of these devices may become unstable or malfunction may occur.

Therefore, there is a method of reducing the generated electromagnetic interference wave as a whole without suppressing the current change of these signals so much. In this method, each signal line is paired with a return line of a current flowing through them, that is, a ground line or a power supply line, or a plurality of pairs of these lines are provided. Groups (hereinafter referred to as signal line groups) are made to be attached to the ferrite core.

Also in such a method, as described above, a component having lead wires on the ferrite core itself is commercially available. However, Japanese Utility Model No. 1-40230, Japanese Utility Model No. 1-42396, and Japanese Utility Model No. 1-423.
As can be seen in Japanese Patent Publication No. 97, Japanese Patent Publication No. 2-351835 and Japanese Patent Publication No. 2-30874, the number of these lead wires is almost two (four in terms of the number of terminals). This is because as the number of lead wires increases, the time and cost required for the ferrite core assembly work will increase significantly, and it is extremely difficult to actually increase the number of lead wires to 8 or more. become.

As a technique for reducing electromagnetic interference waves other than printed wiring boards, there is a technique in which a ferrite core is attached to the interface cable itself (Japanese Utility Model Publication No. 62-14770, Japanese Patent Laid-Open No. Sho 47-14770). 6
3-160300 and Japanese Patent Publication No. 2-34875). However, when connecting the different housings by an interface cable, there are two purposes: reduction of electromagnetic interference waves emitted to the outside and reduction of electromagnetic interference waves incident from the outside.

In order to serve such different purposes at the same time, it has been customary in the past to cover the interface cable with a braided shield wire or wind it with an aluminum tape to provide electromagnetic shielding. When the electromagnetic shield is performed by such a method, it is difficult to attach the ferrite core inside the shielded inside.
Of course, it is relatively easy to attach a ferrite core to the outside of an interface cable that is electromagnetically shielded by a braided shield wire or the like.

FIG. 12 shows a conventional cable connector in which a ferrite core is attached to the outside of the interface cable. The outer surface of the cable core 12 accommodating the signal line group 11 is shielded by a shield material 13 such as aluminum tape. The interface cable 14 having such a structure is attached to a shielded connector case 16 having a metal shell 15 arranged at one end. And interface cable 1
A cylindrical ferrite core 17 is attached to the outer periphery of 4 so as to cover a part thereof.

FIG. 13 shows a structure of such a cable connector, and FIG. 14 shows a state before the assembly of the cable connector. In these figures, the shield material 13 exposed from the interface cable 14 is arranged between the lower connector case 22 and the shield material holding metal fitting 21 so as to be covered, and is fixed by a screw 23. As a result, the shield material 13 is pressed against the metal lower connector case 22 by the shield material pressing metal fitting 21 to maintain electrical contact.

Connector terminals 2 are respectively provided at the end portions of the signal line group 11 drawn out from the interface cable 14.
4 are mounted and these are arranged in the metal shell 15 at predetermined pin positions. In this state, the upper connector case (not shown) is connected to the lower connector case 22.
And fix them with a fixing screw 24. The metal shell 15 is sandwiched by grooves provided in the upper and lower connector cases 22 in advance.
The fixing screw 25 is for fixing the present connector and the connector into which the connector is fitted.

FIG. 15 shows an equivalent circuit of the conventional cable connector described above. Signal line group 1
1 and the shield material (shield wire) 13 mutually have circuit characteristics as a common mode inductor by the action of the ferrite core 17. That is, the signal line group 11 and the shield material 13 have a circuit configuration in which a potential change in the high frequency band does not occur relatively.

[0013]

FIG. 16 is a view for explaining the generation state of electromagnetic interference waves when the conventional cable connector described above is used. It is assumed that the interface cable 14 connects the completely shielded device 21 and the incompletely shielded device 22. Circuits 23, 24 for both devices 21, 22
A signal ground 25 for the frame and a frame ground 26 for the frame (housing) are provided. When the housing shield for one device 22 is incomplete as in this example, only the current change of the signal line pair group including the frame ground 26 can be suppressed, and the electromagnetic interference wave 27 generated from the circuit 24 can be suppressed. Cannot be suppressed sufficiently.

In particular, when a cable is connected to a peripheral device having many openings such as a printer, it is not effective to shield only the outside of the cable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cable connector which can efficiently reduce electromagnetic interference waves generated from a cable at low cost.

Another object of the present invention is to provide a cable connector which effectively reduces electromagnetic interference and is easy to assemble.

[0017]

According to a first aspect of the present invention, there is provided a cable connector in which a plurality of signal lines excluding a shield line or a frame ground line and an inside of a metal case for a connector accommodating the signal lines or an insulating material such as plastic. The magnetic material is arranged so as to surround the plurality of signal lines between the conductive material and the inside of the conductive case in which the surface of the conductive material is covered with metal plating.

That is, according to the first aspect of the present invention, it is more effective to attach a magnetic material such as ferrite to the inside of the cable than to attach the ferrite to the outside of the cable in terms of reducing electromagnetic interference waves generated. I paid attention. In other words, when connecting an interface cable to a device whose electromagnetic shield is incomplete, it is possible to obtain a great effect by attaching a magnetic substance inside the electromagnetic shield such as a braided shield wire. . Similarly to the shield ground line, the frame ground line may be arranged between the outside of the signal line excluding this and the inside of the connector metal case so that the magnetic body surrounds these signal lines.

In the cable connector according to claim 2,
Between the outside of the cable that contains multiple signal lines and the inside of the connector metal case that is placed outside this cable, or the inside of the conductive case where the surface of an insulating material such as plastic is covered with metal plating. In between, the two magnetic bodies are arranged so as to surround at least part of their end faces so as to surround the cable.

That is, according to the second aspect of the invention, according to the same principle as that of the first aspect of the invention, the outside of the cable accommodating a plurality of signal lines and the inside of the connector metal case arranged outside the cable are provided. While arranging the magnetic body between the two, the magnetic body is divided into two and arranged so as to face each other so as to surround the cable, thereby facilitating the assembly of the cable connector.

[0021]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 shows the structure of a cable connector according to an embodiment of the present invention, and FIG. 2 shows a state in which it is cut along the AA 'plane. The shield material 13 exposed from the interface cable 14 is arranged between the lower connector case 22 and the shield material pressing metal fitting 21 so as to be covered, and is fixed by a screw 23. As a result, the shield material 13 is pressed against the metal lower connector case 22 by the shield material pressing metal fitting 21 to maintain electrical contact.

The portion of the cable core 12 covering the signal line group 11 drawn out from the interface cable 14 passes through the recessed portions of the two ferrite plates 32 and 33 each having a semicircular recessed portion in the central portion. , The respective signal lines 11 are drawn out from here. Connector terminals 24 are attached to the ends of these signal lines 11 as shown in FIG. 14, and these are arranged at predetermined pin positions in the metal shell 15. In this state,
The upper connector case 34 is covered on the lower connector case 22, and these are fixed by the fixing screws 24 (see FIG. 14). The metal shell 15 is sandwiched by grooves provided in the upper and lower connector cases 22 in advance.

The two ferrite plates 32, 33 of such a cable connector have their surfaces contacted with each other in advance, and the upper connector case 34 and the lower connector case 22 are screwed together to press them together. It is supposed to do. In this way, the two ferrite plates 32, 3
It is important to bring 3 into close contact with each other in order to bring out the effect of reducing the electromagnetic interference wave on the signal line 11.

FIG. 3 shows an equivalent circuit of the cable connector of this embodiment. As described in FIG. 15, the signal line group 11 and the shield material 13 are interface
The ferrite core 17 and the like arranged outside the cable 14 mutually have the circuit characteristics 41 as common mode inductors. In this embodiment, two ferrite plates 32 and 33 are arranged inside the cable connector. By doing so, the circuit characteristic 42 which becomes a common mode inductor is added only to the signal line group 11.

Modification

FIG. 4 shows a structure of a cable connector according to a first modification of the present invention, and FIG. 5 shows a state in which it is cut along the BB 'plane. Also in this modification, the shield material 13 exposed from the interface cable 14 is arranged between the lower connector case 22 and the shield material holding metal fitting 21 so as to be covered with the shield material pressing metal fitting 21, and is fixed by a screw 23. Predetermined line 51 drawn from the interface cable 14
Other than the signal line group 11 'other than the cable core 12 (see FIG. 2).
The reference line) passes through the recessed portions of the two ferrite plates 32 and 33 each having a semicircular recessed portion in the central portion, from which the respective signal lines 11 'are drawn out.

The wire 51 passes through the outside of the two ferrite plates 32 and 33, and a pin (not shown) arranged at the end thereof is arranged at a predetermined position of the metal shell 15. Pins are attached to the ends of the signal line group 11 'other than the line 51 as described above, and these pins are respectively attached to the metal shell 1'.
5 are arranged at predetermined positions. In this state, the upper connector case 34 is covered on the lower connector case 22, and these are fixed by the fixing screws 24 (see FIG. 14).
The metal shell 15 includes upper and lower connector cases 22.
It is designed to be sandwiched by a groove provided in advance.

In the cable connector of the first modified example, the predetermined line 51 such as the frame ground line was not passed through the two ferrite plates 32 and 33, so the signal line group 11 'excluding this line 51 is used. It means that the circuit which becomes the common mode inductor is added only to. This line 51
Will be connected to other circuits, frames, etc. via the predetermined pins of the metal shell 15.

FIG. 6 shows a structure of a cable connector according to a second modified example of the present invention, and FIG. 7 shows a state in which the cable connector is cut along a C-C 'plane. In this modification, two ferrite plates 32 and 33 are provided with convex portions 61 so as to face the bottom portions of the upper and lower connector cases 34 and 22, respectively, so as not to cause positional deviation inside the cable connector. Is.

FIG. 8 shows a cross section of a cable connector according to a third modification of the present invention. In this modification, two ferrite plates 3 are used as in the second modification.
It has the purpose of preventing the displacement of the positions 2 and 33. For this reason, adhesive material 63 is applied to the bottoms of the upper and lower connector cases 34 and 22, respectively, so that the two ferrite plates 32 and 33 are adhered and fixed to them. It is preferable that the adhesive material has some elasticity even in the solidified state, so that the contact surfaces of the two ferrite plates 32 and 33 come into close contact with each other. A double-sided tape may be attached instead of the adhesive material, or the bottom portions of the upper and lower connector cases 34 and 22 and the two ferrite plates 32 and 33 may be adhered to each other via an elastic material. .

FIG. 9 shows the structure of a cable connector according to a fourth modification of the present invention.
Shows a state in which this is cut along the D-D 'plane. In this modification, two ferrite plates 32 'and 33' are used.
The recesses 71 and 72 are provided at two places on the left and right of the claws 73 and 7 for preventing the ferrite plates 32 'and 33' from coming off.
4 is locked.

Further, in order to bring the end faces of the two ferrite plates 32 'and 33' into close contact with each other in the state where the two ferrite plates 32 'and 33' are positioned in this manner, the supporting portion 7 exerting a force in that direction.
5, 76 are arranged.

FIG. 11 shows the essential parts of this cable connector with the upper connector case attached. FIG. 11 shows the area shown by the broken line 81 in FIG. Support part 7 of upper connector case 34 '
Both ends of 5 project toward the ferrite plate 33 ', which is slightly more than the position where it contacts the ferrite plate 32'. Therefore, as the fixing screw 24 is tightened, the ferrite plate 32 'moves toward the other ferrite plate 33'. Press on. The same applies to the support portion 76 of the lower connector case 22 '. As the fixing screw 24 is tightened, the ferrite plate 3
3'is pressed toward the ferrite plate 32 '. As a result,
The end faces of the two ferrite plates 32 'and 33' are in pressure contact with each other.

[0035]

As described above, according to the first aspect of the present invention, between the plurality of signal lines excluding the shield line or the frame ground line and the inside of the connector metal case that accommodates them, Since the magnetic material is arranged so as to surround these multiple signal lines, only the multiple signal lines excluding the shield line and frame ground line can be set to the common mode inductor state. Effective in suppressing interference waves. Therefore, as compared with the case where the same effect is obtained by the conventional method, there is an advantage that the unit price of the parts becomes relatively low and the assembling work becomes easy. That is, since it is not necessary to perform special processing on a shielded interface cable or the like, it is possible to efficiently reduce the electromagnetic interference wave at low cost and in a short time.

Further, since the electromagnetic interference wave is reduced at the stage of the cable connector, it is not necessary to modify the printed wiring board or the like, and the time and cost required for manufacturing the plate can be saved. Further, since it does not disturb the signal waveform in terms of an equivalent circuit, it is possible to select a ferrite material having a large effect of attenuating the harmonic current, and in this sense, it is also effective as a countermeasure against electromagnetic interference waves.

According to the second aspect of the invention, between the outer side of the cable accommodating the plurality of signal lines and the inner side of the connector metal case arranged outside the cable,
The two magnetic bodies surround the cable so that at least a part of their end faces are in contact with each other. Therefore, the cable can be easily attached to the cable connector, and the magnetic body can be easily changed even after the connector is assembled. That is, the cable connector can be easily recombined into an optimum one according to the frequency or level of the electromagnetic interference wave in question.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which an upper connector case of a cable connector according to an embodiment of the present invention is removed.

FIG. 2 is an AA ′ of the cable connector shown in FIG.
FIG.

FIG. 3 is an equivalent circuit of the cable connector of this embodiment.

FIG. 4 is a plan view showing a state in which an upper connector case of a cable connector according to a first modified example of the present invention is removed.

5 is a BB ′ of the cable connector shown in FIG.
FIG.

FIG. 6 is a cross-sectional view showing a state in which an upper connector case of a cable connector according to a second modified example of the present invention is removed.

7 is a C-C 'of the cable connector shown in FIG.
FIG.

FIG. 8 is a cross-sectional view of a cable connector according to a third modified example of the present invention.

FIG. 9 is a plan view of a cable connector with an upper connector case removed according to a fourth modification of the present invention.

[Fig. 10] D- of the cable connector shown in Fig. 9.
It is a D'sectional view.

FIG. 11 is a plan view showing a main part of this cable connector in a state in which an upper connector case is attached in a fourth modification.

FIG. 12 is a view showing a cross section and a plane of a conventional cable connector in which a ferrite core is attached to the outside of an interface cable.

FIG. 13 is a plan view showing a state in which an upper connector case of a conventional cable connector is removed.

FIG. 14 is a plan view showing a state before assembly of the cable connector shown in FIG.

FIG. 15 is an equivalent circuit of a conventional cable connector.

FIG. 16 is a principle diagram showing a principle of generating an electromagnetic interference wave when a conventional cable connector is used.

[Explanation of symbols]

11, 11 '... Signal line group, 12 ... Cable core, 13 ... Shielding material, 14 ... Interface cable, 15 ... Metal shell, 21 ... Shielding material holding metal fitting, 22, 22'
... Lower connector case, 32, 32 ', 33, 33' ...
Ferrite plate, 34 ... Upper connector case, 51 ... Wire,
61 ... Convex part, 63 ... Adhesive material, 73 ... Claw, 75 ... Support part

Claims (2)

[Claims] 1. A magnetic body is arranged between a plurality of signal lines excluding the shield line or the frame ground line and the inside of a conductive case for a connector that accommodates the signal lines so as to surround the plurality of signal lines. The connector for the cable which is characterized by being. 2. Between the outside of the cable accommodating a plurality of signal lines and the inside of the electrically conductive case for a connector arranged outside the cable, two magnetic bodies surround the cable. A connector for a cable, wherein at least a part of the end surface of the connector is arranged in contact with the connector.