JP2014164973A - High-frequency waterproof connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waterproof connector capable of reducing an impedance.SOLUTION: A high-frequency waterproof connector comprises: a housing 10 to which a plurality of cavities 11 into each of which a terminal 30 connected with a core wire 41 of an electric wire 40 is inserted are formed; and a rubber stopper 20 at least a part of which is inserted into each cavity 11, and tightly adhered to an outer surface of the electric wire 40 and an inner surface of the cavity 11. The rubber stopper 20 is formed of a conductive rubber material containing a conductive material. It is preferred that the conductive rubber material configuring the rubber stopper 20 has an elastic modulus of 6 MPa or more and 38 MPa or less, and has a volume resistivity of 500 Ω cm or less.

Description

  The present invention relates to a high-frequency waterproof connector having a waterproof function.

  The following Patent Document 1 describes a waterproof connector in which a rubber plug is inserted into a cavity of a housing. In this type of waterproof connector, the penetration of water into the cavity is prevented by the action of the inserted rubber plug.

JP 2009-48828 A

  This type of general waterproof connector has a wider distance between terminals (between the ends of the electric wire) than a non-waterproof connector, for example, because a region for inserting the rubber plug is secured in the cavity of the housing. Become. Therefore, the conventional waterproof connector has a problem that the impedance at the connection portion is larger than that of the non-waterproof connector. Such an increase in impedance causes an increase in transmission loss, particularly when used for high-frequency communication.

  In view of the above circumstances, the problem to be solved by the present invention is to provide a high-frequency waterproof connector capable of reducing impedance.

  In order to solve the above problems, the high-frequency waterproof connector according to the present invention includes a housing in which a plurality of cavities into which terminals connected to the core of an electric wire are inserted, and at least a part of which is inserted into each of the cavities And a rubber plug closely contacting the outer surface of the electric wire and the inner surface of the cavity, wherein the rubber plug is formed of a conductive rubber material including a conductive material.

  The conductive rubber material constituting the rubber plug has an elastic modulus of 6 MPa to 38 MPa and a volume resistivity of 500 Ω · cm or less.

  In the high-frequency waterproof connector according to the present invention, since the rubber plug that prevents water from entering the cavity is formed of a material containing a conductive material, the impedance can be made smaller than that of a conventional waterproof connector.

  Moreover, if the rubber plug is made of a material having an elastic modulus of 6 MPa or more and 38 MPa or less and a volume resistivity of 500 Ω · cm or less, high-frequency waterproofing that exhibits excellent waterproof properties and electrical properties (impedance reduction effect). It can be a connector.

It is the figure which showed typically the cross section of the high frequency waterproof connector concerning embodiment of this invention.

  A high-frequency waterproof connector 1 (hereinafter simply referred to as a waterproof connector 1) according to an embodiment of the present invention will be described with reference to FIG. The waterproof connector 1 according to the present embodiment is a multipolar connector that can electrically connect a plurality of electric wires 40 at a time, and is an in-vehicle connector used for high-frequency communication in a vehicle. The waterproof connector 1 according to this embodiment includes a housing 10 and a rubber plug 20.

  The housing 10 is a member made of an insulating material such as a synthetic resin, and has a plurality of cavities 11 formed therein. Examples of the material include PBT. A terminal 30 connected to the core wire 41 of the electric wire 40 is inserted into each cavity 11. A well-known structure can be applied to the structure of the terminal 30 and the structure for fixing the terminal 30 to the housing 10.

  The rubber plug 20 is a cylindrical elastic body that is inserted from the back of the cavity 11 (inlet for inserting the terminal 30). That is, a through hole penetrating in the axial direction is formed, and the electric wire 40 is passed through the through hole. A rubber plug mounting portion 12 is formed behind each cavity 11 of the housing 10, and the rubber plug 20 is accommodated inside the rubber plug mounting portion 12. The thickness of the rubber plug 20 (distance between the inner surface and the outer surface of the rubber plug 20) is set larger than the distance between the outer surface of the electric wire 40 and the inner surface of the cavity 11 in a state where the terminal 30 of the electric wire 40 is inserted into the cavity 11. The Therefore, when the rubber plug 20 is accommodated in the cavity 11, it is sandwiched between the outer surface of the electric wire 40 (sheath 42) and the inner surface of the cavity 11 and elastically deforms. That is, it adheres closely to the outer surface of the electric wire 40 and the inner surface of the cavity 11 and prevents water from entering from the rear of the cavity 11.

  The material constituting the rubber plug 20 is a conductive rubber material in which a conductive material (conductive particles such as carbon black) is blended with a rubber component. Therefore, the volume resistivity is lower than that of a conventional rubber plug (a rubber plug not including a conductive material), which is effective in reducing impedance.

  However, if the proportion of the conductive material is increased too much, the elastic modulus increases and the flexibility decreases, so the waterproofness decreases. Further, even if the elastic modulus becomes too small, the strength is lowered, so that the waterproof property when the water pressure is high is lowered. In the waterproof connector 1 according to the present embodiment, the rubber plug 20 is made of a conductive rubber material that exhibits an excellent waterproof function and is also effective for impedance reduction (impedance matching).

  Hereinafter, the present invention will be described in detail with reference to examples. The present invention is not limited to these examples.

  A plurality of types of waterproof connectors using rubber plugs having different elastic moduli and volume resistivity were prepared, and their waterproof properties and electrical properties (impedance) were evaluated. The results are shown in Table 1. The elastic modulus (Young's modulus) was measured according to JISK6251 and the volume resistivity was measured according to JISK6271.

  The waterproof property was determined by flowing 5 kPa compressed air in water for 10 seconds. As a result, “X” indicates that water leaked, “◯” indicates that there was a slight water leak, and “◎” indicates that there was no water leak.

  The electrical characteristics are assumed to be used for high-frequency communication, and those having an impedance in the range of 100 ± 30Ω are good. More preferably, it is in the range of 100 ± 15Ω. Those outside the range of 100 ± 30Ω do not satisfy the required electrical characteristics. In addition, the impedance measured the differential impedance value of 50 MHz by applying the open short method to the structure which attached the electric wire of length 5mm and 0.35sq. The electric wire used in this measurement was made as short as 5 mm to reduce the influence of the cable impedance.

  Note that the housing size (the housing is a general-purpose waterproof connector size for automobiles manufactured by Sumitomo Wiring Systems (for example, 025 female, male 6188-4787, 6189-1161, 040 female, male 6189-7039, 6188-4776)). Was changed as shown in Table 1. The dielectric constant (material) of the housing was also changed as shown in Table 1. The rubber plug used had the same shape as a waterproof connector (025 type, 040 type) for automobiles manufactured by Sumitomo Wiring Systems.

  As shown in Table 1, in order to obtain a connector that exhibits excellent waterproof properties, the elastic modulus of the rubber plug is desirably 6 to 38 MPa. More desirably, it is 9 to 32 MPa. If the elastic modulus of the rubber plug is too high (low flexibility), the adhesion between the rubber plug and the outer surface of the electric wire or between the rubber plug and the inner surface of the cavity is presumed to decrease the waterproofness. On the other hand, when the elastic modulus of the rubber plug is too low (the rigidity is low), it is assumed that water enters when the water pressure is high.

  In order to obtain a connector that exhibits excellent electrical characteristics, it is desirable to set the volume resistivity of the rubber plug to 500 Ω · cm or less. Thereby, the impedance of the obtained connector can be made into the range of 100 +/- 30ohm. More desirably, the volume resistivity of the rubber plug is 8 Ω · cm or less.

  As described above, when the ratio of the conductive material included in the conductive rubber material constituting the rubber plug is increased, the volume resistivity of the rubber plug is decreased, so that the connector is excellent in terms of electrical characteristics. Since the rate increases and flexibility decreases, there is a problem in terms of waterproof properties. On the other hand, when the ratio of the conductive material contained in the conductive rubber material constituting the rubber plug is reduced, the elastic modulus of the rubber plug is reduced, and the connector is excellent in terms of waterproof properties (however, in Comparative Example 2 and Comparative Example 6). However, there is a problem in terms of electrical characteristics because the volume resistivity of the rubber plug is increased. From the above points, it is desirable to select the conductive rubber material constituting the rubber plug within a range where the elastic modulus is 22 to 32 MPa and the volume resistivity is 8 to 500 Ω · cm.

  The rubber plug material selection method can be applied even when the size of the housing or the dielectric constant of the material constituting the housing changes as shown in Table 1. If the size of the housing becomes too large, the gap between cavities may be widened, so the required impedance reduction effect may not be obtained, but a conventional rubber plug made of a material that does not contain conductive material is used. There is no difference that the impedance can be reduced as compared with the case of the case. However, if the space between the cavities is narrow, the ratio of the rubber plugs in the region between the terminals (wires) becomes small, and the characteristics of the rubber hardly affect the impedance. Therefore, the housing is a 025 type or 040 type. It is preferable that the distance between the cavities is relatively small.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments (examples), and various modifications can be made without departing from the gist of the present invention.

  For example, the shape of the rubber plug is not limited to that shown in FIG. What is necessary is just to insert in the cavity in order to prevent permeation of the water into the cavity of a housing.

DESCRIPTION OF SYMBOLS 1 Waterproof connector 10 Housing 11 Cavity 20 Rubber plug 30 Terminal 40 Electric wire 41 Core wire

Claims (2)

A housing in which a plurality of cavities into which terminals connected to the core of the electric wire are inserted are formed;
A rubber plug that is inserted into each cavity at least partially, and is in close contact with the outer surface of the electric wire and the inner surface of the cavity;
With
A high-frequency waterproof connector, wherein the rubber plug is formed of a conductive rubber material including a conductive material.   2. The high-frequency waterproof connector according to claim 1, wherein the conductive rubber material constituting the rubber plug has an elastic modulus of 6 MPa to 38 MPa and a volume resistivity of 500 Ω · cm or less.

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