JPH0341433Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a coaxial connector mounting structure, and in particular, a coaxial connector for preventing interference radio waves from being radiated from a coaxial connector attached to an electronic device. Regarding the mounting structure.

[Prior art and its problems]

2. Description of the Related Art Connectors for connecting cables are used in electronic devices such as measuring instruments. Especially in impedance measuring instruments, BNC connectors (MIL
(Refer to Standard C-39012, etc.), coaxial connectors such as 3-core coaxial connectors are often used, but depending on the usage of the measuring instrument (for example, floating measurement), it may be necessary to float the connector using direct current. be.

Conventionally, in such cases, a support member made of plastic (relative permittivity: about 2 to 3), which has excellent insulation properties and mechanical strength, has been inserted between the connector body and the chassis. However, this conventional example has the disadvantage that the potential of the outer sheath (outer conductor) of the connector becomes unstable, and internal noise fluctuates the potential, radiating interference waves to the outside.

Conventionally, in order to prevent the radiation of interference waves, the connector body was insulated from the chassis of the impedance measuring instrument body using plastic, and the outer conductor of the connector and the chassis were connected using a regular capacitor with leads. . This allows the connector to be floated in direct current and grounded in alternating current.

However, the wire for connecting the capacitor to the connector and chassis creates an inductance (typically 1 cm of wire is approximately
It can be considered to have an inductance of 10nH)
Therefore, the inductor and the capacitor constitute a series resonant circuit, and the impedance becomes non-negligible in a high frequency range. For example, if the wire is 1 cm, that is, the inductance is 10 nH, and the capacitor capacitance is 1000 pF, then
In the frequency range above 50MHz, the grounding effect disappears. Therefore, EMC (Electromagnetic
In the frequency range of 100 MHz and above, which is a particular problem with countermeasures (Compatibility), the drawback was that it was not possible to prevent the radiation of interference waves.

[Problem that the invention attempts to solve]

The present invention was devised to eliminate the drawbacks of the prior art described above, and its purpose is to provide a nearly pure capacitor without producing inductance when a coaxial connector is attached to the chassis of an electronic device. By grounding in an alternating current manner, we provide a coaxial connector mounting structure that has sufficient grounding effects even in high frequency ranges.
The purpose is to be able to take EMC measures. Another object is to provide a mounting structure that can be applied to common coaxial connectors on the market.

[Means for solving problems]

In short, the present invention includes an electrically conductive structural material constituting an electronic device, a coaxial connector, and a support member made of a dielectric material that provides mechanical support and DC insulation between the structural material and the coaxial connector. In the coaxial connector mounting structure, the supporting member is made of a dielectric material with a high dielectric constant, and the inner end surface of the opening provided in the structural member;
A capacitor that is inserted between the outer conductor of the coaxial connector, provides mechanical support for the coaxial connector in the radial direction relative to the structural member, and grounds the outer conductor in alternating current with respect to the structural member. It is characterized by:

〔Example〕

Hereinafter, the present invention will be explained based on embodiments shown in the drawings. FIG. 1 is a front view showing an embodiment of the present invention;
FIG. 2 is a partially sectional side view thereof.

The coaxial connector mounting structure according to the embodiment includes a main body chassis 1, which is an example of a conductive structural material constituting an impedance measuring device (not shown), which is an example of an electronic device, a support member 2, and a coaxial connector 3. are doing.

The chassis 1 is at ground potential and is provided with a circular opening 11 into which the connector 3 is to be attached.

The support member 2 is made of a dielectric material with a high dielectric constant (high relative permittivity), specifically barium titanate (BaTiO ₃ ), which is most commonly known as a dielectric material for ceramic capacitors, or , made of a material containing barium titanate (relative permittivity of several thousand). The relative permittivity changes depending on temperature and frequency, but the values of the relative permittivity used in this specification are based on commonly available dictionaries,
It can be considered that this is a value measured under conditions conventionally used in specifications tables of handbooks, material catalogs, etc.

The support member 2 has an annular shape, and more specifically, it has a shape in which a plurality of hollow cylindrical shapes 21 and 22 having different wall thicknesses are integrally joined. In addition, since the example is illustrated in a large size for easy understanding, the ratio of the dimensions of each part of the support member is as follows.
It may be different from the actual situation.

The coaxial connector 3 is a female BNC connector (contact seat), and connection to an external cable is made via a male BNC connector (not shown).
The connector 3 includes a core wire (inner conductor) 5, an insulator 6,
It consists of an outer sheath (outer conductor) 4 and an inner conductor 5.
and the outer conductor 4 are connected to predetermined positions inside the impedance measuring device via the inner conductor and outer conductor of the coaxial cable 7, respectively. The outer conductor 4 is provided with a flange 51 .

As shown in FIG. 2, the coaxial connector 3 is positioned such that the central axis of the coaxial connector 3 passes through the opening 11, and passes through the opening 11. The coaxial connector 3 has a thread 42 and is fastened with a nut 8. If the nut 8 is a conductor, the outer conductor 4 and the chassis 1
conducts, so it needs to be an insulator (dielectric). However, if a suitable insulating member is inserted between the nut and the chassis 1, a nut made of a conductor, for example a metal, can also be used. As shown in the figure, in the fastened state, the outer circumferential surface 21a of the support member 2 is
It contacts the inner end surface 11a of the opening, and the inner surface 2a of the support member 2 contacts the outer surface 4a of the cylindrical portion of the outer conductor 4. This provides mechanical support for the coaxial connector 3 in the vertical direction in the drawing, and also forms a capacitor between the cylindrical portion of the outer conductor 4 and the support member 2. Furthermore, support member 2
The end surface 22a on the right side in the drawing contacts the flange 41 of the external conductor 4, and the end surface 22b on the left side in the drawing contacts the plane around the opening 11 of the chassis 1, providing mechanical support in the left-right direction in the drawing and providing external conductor 4
A capacitor is formed between the flange 41 and the chassis 1. Of course, it goes without saying that the boundaries between the two capacitors are not strictly defined.

The embodiment of the present invention is constructed as described above, and since the formed capacitor does not use wire, no inductor is formed, and therefore a resonant circuit unlike the conventional example is not formed. Furthermore, since the capacitor formed in the embodiment has a cylindrical shape, the current in the dielectric flows radially and no magnetic flux is generated. Therefore, the connector 3 can be constructed only by a capacitor that can be considered almost pure. Since it can be grounded in an alternating current manner, impedance does not increase due to the influence of inductance even in the high frequency range of 100 MHz or higher, and the grounding effect can be made effective.

In the above embodiment, the dielectric of the support member 2 was described as being barium titanate, but in practice, any dielectric with a high dielectric constant, with a dielectric constant of 100 or more at room temperature, can be used. Able to achieve the purpose of the idea. Of course, the number of dielectric constant 100 described here does not indicate an accurate boundary condition, and it is conceivable that the dielectric constant may be around 100. in short,
It is only necessary to obtain a sufficient grounding effect under the usage conditions of the electronic equipment to which the present invention is applied, particularly regarding the frequency.

Further, in the above embodiments, the electronic device has been described as an impedance measuring device, but it goes without saying that the electronic device is not limited to this. In addition, although the conductive structural material was explained as chassis 1,
There is no need to stick to the name "Siyashi",
Various things such as cases and panels can be considered, and it goes without saying that it is not necessarily limited to the main body chassis, but may be any other various partition walls.

Furthermore, in the above embodiment, the coaxial connector 3 is
Although the description has been made assuming that it penetrates through the opening 11, it is not limited to this.

In addition, in the above embodiment, the support member 2 and
The outer conductor 4 and the chassis 1 have been described as being in direct contact with each other. However, it goes without saying that even if another conductor is interposed between the outer conductor 4 and the support member 2 or between the support member 2 and the chassis 1, the same effect as in the above embodiment can be obtained. Therefore, implementations including such inclusions are also included in the scope of the above-mentioned utility model registration claims. In this case, in interpreting the claims of the utility model registration, the other conductor may be considered to be part of the outer conductor 4 or the chassis 1.

〔effect〕

Since the present invention is constructed and operates as described above, an inductor is not formed in the AC grounding means as in the conventional example, so that the coaxial connector can be grounded in an AC manner even in a high frequency range.
This provides the effect of preventing the radiation of interfering radio waves.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the present invention, and FIG. 2 is a partially sectional side view of the embodiment of the present invention. 1: Chassis, which is an example of a conductive structural member,
2: Support member, 3: Coaxial connector, 11: Opening, 4: Outer conductor.

Claims (1)

[Claims for Utility Model Registration] 1. A support consisting of a conductive structural material constituting an electronic device, a coaxial connector, and a dielectric material that provides mechanical support and DC insulation between the structural material and the coaxial connector. In the coaxial connector mounting structure, the supporting member 2 is made of a dielectric material with a high dielectric constant, and the opening 11 provided in the structural member 1 is
is inserted between the inner end surface 11a of the coaxial connector and the outer conductor 4 of the coaxial connector, provides mechanical support of the coaxial connector in the radial direction with respect to the structural member, and connects the outer conductor with respect to the structural member in an alternating current direction. A mounting structure for a coaxial connector, characterized in that it forms a capacitor to be grounded. 2. The coaxial connector mounting structure according to claim 1, wherein the high dielectric constant dielectric is barium titanate. 3. The coaxial connector mounting structure according to claim 1, wherein the high dielectric constant dielectric is a substance containing barium titanate. 4. The coaxial connector mounting structure according to claim 1, 2, or 3, wherein the opening is circular. 5. The coaxial connector mounting structure according to claim 1, 2, 3, or 4, wherein the support member is annular. 6. The coaxial connector mounting structure according to claim 5, wherein the support member has a hollow cylindrical shape. 7. The coaxial connector according to claim 6, wherein the support member has a shape in which a plurality of cylindrical shapes having different wall thicknesses are integrally joined. Mounting structure. 8. Utility model registration claim 1, 2, or 3, characterized in that the outer conductor of the coaxial connector is provided with a flange.
The mounting structure of the coaxial connector according to item 1 or 4 or 5 or 6 or 7. 9. Utility model registration claim 4, characterized in that the capacitor is formed between the outer surface of the cylindrical portion of the outer conductor and the inner surface of the cylindrical support member, or A mounting structure for a coaxial connector according to item 5 or 6 or 7 or 8. 10. The coaxial connector mounting structure according to claim 8, wherein the capacitor is formed between the flange of the outer conductor and the plane of the structural member. . 11 The coaxial connector is characterized in that it penetrates the structural material, as claimed in claim 1 or 2 or 3 or 4 or 5 or 6 of the utility model registration claim. Section or Section 7 or Section 8
Mounting structure of the coaxial connector described in item 9 or item 10. 12 Utility model registration claim 1, 2, 3, 4, or 5, characterized in that the structural material is a body chassis of an electronic device.
The mounting structure of the coaxial connector according to item 6 or 7 or 8 or 9 or 10 or 11. 13. The coaxial connector mounting structure according to claim 12, wherein the electronic device is a measuring instrument. 14 Utility model registration claim 13, characterized in that the measuring device is an impedance measuring device
Coaxial connector mounting structure described in section.