Patent Description:
A transmission path, such as a coaxial cable, including an insulator provided between a central conductor and an external conductor has excellent signal transmission characteristics since inductance of the central conductor, which serves as a signal line, and capacitance (electrostatic capacity) between the conductors are constant for each unit length. A characteristic impedance Z (Ω) of the transmission path is set to a predetermined value corresponding to the values of the inductance L (H) and the capacitance C (F) for each unit length.

When such a transmission path is connected to other devices, failure in impedance matching to match the characteristic impedance of the transmission path with the reference impedance of such a device causes signal reflection at a boundary point of the transmission path where the characteristic impedance changes, resulting in waveform distortion.

In view of this, a connector whose transmission path is connected to other devices needs to avoid deterioration in characteristic impedance due to reflection.

<CIT> describes such a conventional connector. On the basis of the fact that capacitance is increased as an area over which internal and external contacts are opposed to each other in the radial direction in male and female connector members is increased, a distance between the internal and external contacts is reduced, or the permittivity of an insulator provided between these contacts is increased, a male pin contact portion is set to a high impedance region so as to compensate for a low impedance of a female socket connector portion for the purpose of adjusting a characteristic impedance (Z = (L/C)<NUM>/<NUM>). In this manner, the connector can obtain good transmission characteristics (see paragraphs <NUM>, <NUM>, and <NUM>, for example, in <CIT>).

Further, <CIT> describes a connection device which comprises first and second connectors. The first connector has a sleeve having axially extending slots at a distal end to define tines yieldable resiliently inward, and a resilient seal encircling the sleeve proximally of the slots. The second connector has a shroud dimensioned to receive the distal end of the first connector sleeve within the shroud and to engage the first connector resilient seal when the sleeve is fully received within the shroud. Furthermore, <CIT> describes a high current connector, having an inner conductor contact for carrying current, an outer conductor part, and an isolator part which keeps the inner conductor contact spaced apart from the outer conductor part, wherein a resiliently compressible damping element is provided on the connector in such a way that, when a complementary counterpart connector is inserted into the connector, the element is resiliently compressible in an insertion direction and the mobility of the isolator part is reduced with respect to the inner conductor contact and/or with respect to the outer conductor part. <CIT> describes a connector module that has an inexpensive configuration and a high shielding ability is provided. The connector module includes a terminal module and a shield case. The terminal module has a central conductor, a tubular insulator holder that supports the central conductor, and a tubular conductive shell. A bottom portion of the shield case has multiple elastic portions that are capable of elastic deformation and are bent from and protrude from an edge portion of an opening portion for passage of the terminal module. The terminal module is joined to the shield case in a state where the annular recession portion of the conductive shell and the elastic portions are in electrical contact with each other. <CIT> describes a connector which provides moisture proof sealing and electrical grounding of selected contacts, especially for coaxial contact devices. The connector includes a conductive shell assembly with a rear wall that has a large opening therein. An insulator device lies in the shell assembly and at least one coaxial contact device lies in the insulator device. A ground plane formed by a sheet of electrically conductive material has an outer portion trapped between the insulator device and the rear wall of the shell assembly, and has an inner portion that directly engages the outer contact of the coaxial contact device to ground it. The shell assembly includes front and rear tubular shell parts, with the tubular rear shell part having a greater inside width and length than that of the front tubular shell part. The insulator device includes a front insulator of elastomeric material having a peripheral portion that is deformed rearwardly and radially inwardly by the rear end of the front tubular shell part.

With the conventional connector as described above, however, a gap is created between opposed faces of insulators in male and female connectors if variations in dimensions of each element or variations in mating angle, for example, occur in mating parts to create male-female mating. As a result of change in permittivity due to such discontinuity in the insulator layer, mismatch occurs in the characteristic impedance set constant along the transmission path, thus deteriorating the transmission characteristics.

In view of this, it is an object of the present invention to provide a connector capable of effectively reducing deterioration in characteristic impedance in mating parts and thus obtaining excellent transmission characteristics.

(<NUM>) In order to achieve the foregoing object, the present invention provides a connector according to claim <NUM>, the connector including:
an internal contact extending in an axial direction and disposed at an inner position in a radial direction; an external contact extending in the axial direction and disposed at an outer position in the radial direction; and an insulator disposed between the internal contact and the external contact. At least one of the internal contact and the external contact includes, on one side in the axial direction, a mating part to be mated with a corresponding counterpart contact at a predetermined radial contact pressure. The insulator includes a first insulator part exposed to the one side in the axial direction, and a second insulator part disposed on the other side in the axial direction relative to the first insulator part. The first insulator part is made of an elastic material capable of being easily deformed elastically in the radial direction as compared to the second insulator part.

With such a configuration according to the present invention, when the mating part of the at least one of the internal contact and the external contact is mated with the corresponding counterpart contact at the predetermined radial contact pressure, the first insulator part disposed on the one side in the axial direction can be easily deformed elastically. This can facilitate elastic deformation and elastic recovery for the mating of the mating part with the counterpart contact, and can effectively reduce the creation of a gap between the insulator and the internal contact or the external contact after the elastic recovery. As the result, deterioration in characteristic impedance due to permittivity change resulting from the creation of such a gap space can be effectively reduced.

(<NUM>) In the aspect of the present invention, the mating part may include a plurality of mating claw portions disposed on the one side in the axial direction and having a substantially divided cylindrical shape as a whole, and a supporting cylindrical portion for integrally supporting the plurality of mating claw portions at one ends thereof with a plurality of slits being interposed between the plurality of mating claw portions. The first insulator part may be disposed within a regional range closer to the one side in the axial direction than the supporting cylindrical portion.

In implementation with such a configuration, when the mating part is mated, the plurality of mating claw portions are bent in the radial direction to compress the first insulator part and elastically recovered together with the first insulator part. Thus, the mating operation can be facilitated, and the creation of a gap space between the insulator and the internal contact or the external contact can be reduced more effectively.

(<NUM>) In the aspect of the present invention, widths of the plurality of slits may each be set to have a larger width on a base end side of the plurality of mating claw portions supported by the supporting cylindrical portion and to have a smaller width on a tip side of the plurality of mating claw portions.

In implementation with such a configuration, a required bending amount and strength of the plurality of mating claw portions can be attained without providing, for example, a hole to cause stress concentration in the plurality of mating claw portions. In addition, the wider slit width can further facilitate the elastic deformation of the first insulator part in the radial direction, thereby making it possible to reduce the creation of a gap space between the insulator and the internal contact or the external contact more effectively. Furthermore, the application of a load to the second insulator part can be reduced more effectively.

(<NUM>) According to the present invention, one end face of the first insulator part projects more toward the one side in the axial direction than the external contact, and the internal contact includes a penetration part that penetrates the insulator, a projecting end part that projects more toward the one side in the axial direction than the first insulator part, and a protrusion that protrudes in the radial direction toward the first insulator part from the penetration part.

With such a configuration, an axial displacement of the first insulator part can be restricted by the protrusion of the internal contact even when the first insulator part is brought into elastic abutment with the counterpart insulator. Thus, no gap is created in the abutting portion, and no large load is applied to the second insulator part.

(<NUM>) In the aspect of the present invention, the first insulator part may have a relative permittivity equivalent to that of the second insulator part.

In this case, deterioration in characteristic impedance in the mating part can be effectively reduced.

(<NUM>) In the aspect of the present invention, the first insulator part may be integrally coupled to the second insulator part.

With such a configuration, the first insulator part can be disposed at a stable position and with a stable orientation so as not to create a gap in the insulator portion.

(<NUM>) Another aspect of the present invention provides a connector including a male connector member and a female connector member, each including: an internal contact extending in an axial direction and disposed at an inner position in a radial direction; an external contact extending in the axial direction and disposed at an outer position in the radial direction; and an insulator disposed between the internal contact and the external contact. The male connector member of the male and female connector members includes first and second male mating parts to be mated with corresponding counterpart contacts at a predetermined radial contact pressure. The female connector member of the male and female connector members includes first and second female mating parts to be mated with corresponding counterpart contacts at a predetermined radial contact pressure. The insulator of the male connector member includes a first insulator part exposed to one side in the axial direction, and a second insulator part disposed on the other side in the axial direction relative to the first insulator part. The first insulator part is made of an elastic material capable of being easily deformed elastically in the radial direction as compared to the second insulator part.

With such a configuration, the first insulator part of the male connector member can be easily deformed elastically when the male and female connector members are mated with each other. This can facilitate elastic deformation and elastic recovery for the mating of the male connector member with the corresponding counterpart contact, and can effectively reduce the creation of a gap between the insulator and the internal contact or the external contact. As the result, deterioration in characteristic impedance due to permittivity change resulting from the creation of such a gap space can be reduced.

(<NUM>) In the aspect of the present invention, one end of the first insulator part of the male connector member may project more toward the one side in the axial direction than the external contact of the male connector member.

In this case, since the one end of the first insulator part in the male connector member is brought into contact with the insulator of the female connector member earlier than the external contact. Thus, the insulators of the male and female connector members are disposed in a connected state via the first insulator part provided therebetween without any gap not only in the radial direction but also in the axial direction.

(<NUM>) In the aspect of the present invention, the internal contact of the male connector member may project more toward the one side in the axial direction than the first insulator part and the external contact of the male connector member to form the first male mating part, and the internal contact of the female connector member may include a first female mating part with a length in the axial direction larger than or equal to that of the first male mating part.

With the use of such a configuration, the shape and orientation of the first insulator part in the mated state of the male and female connector members can be stably maintained, and contact between the internal contacts of the connector members as well as contact between the external contacts thereof can be stably maintained.

According to the aspect(s) of the present invention, deterioration in characteristic impedance of the transmission path due to capacitor change resulting from crush or clearance of the insulators in the mating parts of the connector.

<FIG> illustrate a connector according to a first embodiment useful for understanding the invention.

The configuration of the connector will be described first.

As shown in <FIG>, a connector <NUM> of the present embodiment includes a plug <NUM> and a receptacle <NUM> (which are a male connector member and a female connector member, respectively) each extending in an axial direction (i.e., the horizontal direction in <FIG>). The connector <NUM> is configured so that the plug <NUM> can be engaged with the receptacle <NUM> (the female connector member) to have protrusion-recess mating with a shell mated depth Lf at their connection ends, and the plug <NUM> can be detached from the receptacle <NUM> to have an unmated state.

The connector <NUM> of the present embodiment has features in the structures of mating parts of the male and female connector members. The structures of end parts (a right end part of the plug <NUM> and a left end part of the receptacle <NUM> in <FIG>) to be connected to, or mounted on, other devices, substrates, or cables as coaxial connectors or coaxial plugs, for example, are not limited to any particular structures. Any conventionally-known connecting or mounting structure can be employed. Although the detailed description and illustration of such a connecting structure to a coaxial cable or a device are herein omitted, known mounting structures onto printed circuit boards (see <CIT>, for example), known connecting structures between coaxial cables and device substrates (see <CIT>, for example), known surface mounting structures (see <CIT>, for example), known external connecting structures of antennas (see <CIT>, for example), and known connecting structures to precision devices (see <CIT>, for example) can be used, for example.

As shown in <FIG>, the plug <NUM>, which is the male connector member, includes: an internal contact <NUM> disposed at a radially inner position; a cylindrical shell-shaped external contact <NUM> extending in the axial direction and disposed at a radially outer position; and a thick cylindrical insulator <NUM> disposed between the internal contact <NUM> and the external contact <NUM>.

As shown in <FIG>, <FIG>, <FIG> and <FIG>, the internal contact <NUM> of the plug <NUM> integrally includes: a penetration part 11a having a generally circular cross-section, which is formed by a wire rod-shaped conductor and penetrates the center of the insulator <NUM>; and a first male mating part 11b (a projecting end part) formed to have a diameter smaller than that of the penetration part 11a and projecting more toward one side (the left side in <FIG>) in the axial direction than the insulator <NUM>. The tip of the first male mating part 11b has a generally conical shape. The internal contact <NUM> projects more toward the one side in the axial direction than the external contact <NUM>, and one end face 31a of a first insulator part <NUM> is disposed between the tip of the internal contact <NUM> and the tip of the external contact <NUM> in an insertion direction when the plug <NUM> is mated with the receptacle <NUM> (hereinafter, referred to simply as a mating direction).

As shown in <FIG>, <FIG>, <FIG>, the receptacle <NUM>, which is the female connector member, includes: an internal contact <NUM> and an external contact <NUM> arranged coaxially with each other; and a thick generally cylindrical insulator <NUM> made of an insulating material (a dielectric material) and disposed between the internal contact <NUM> and the external contact <NUM>.

The internal contact <NUM> includes a slotted socket-shaped first female mating part 21b to create protrusion-recess mating with the first male mating part 11b of the internal contact <NUM> in the plug <NUM>. The internal contact <NUM> is accommodated in the insulator <NUM>.

The external contact <NUM> has a tubular (cylindrical) shell shape and is disposed at a position radially outward of the internal contact <NUM>. The external contact <NUM> projects more toward the other side (the right side in <FIG>) in the axial direction than the internal contact <NUM> and the insulator <NUM> while surrounding the internal contact <NUM> and the insulator <NUM>.

As shown in <FIG>, the external contact <NUM> of the plug <NUM>, which is the male connector member, includes a second male mating part 12f to be mated with its corresponding counterpart contact <NUM> at a predetermined radial contact pressure at a position closer to the front end of the external contact <NUM> in the mating direction but posterior (the right side in <FIG>) to the first male mating part 11b of the internal contact <NUM> in the mating direction.

As counterpart contacts corresponding to the internal contact <NUM> and the external contact <NUM> of the plug <NUM>, the receptacle <NUM>, which is the female connector member, includes a second female mating part 22f to be mated with the second male mating part 12f of the external contact <NUM> at a predetermined radial contact pressure in addition to the first female mating part 21b to be mated with the first male mating part <NUM>1b of the internal contact <NUM> at a predetermined radial contact pressure.

As just described, the plug <NUM> (the male connector member) in the present embodiment includes, on the one side (the left side in <FIG>) of at least one of, e.g., both of, the internal contact <NUM> and the external contact <NUM> in the axial direction, the first male mating part 11b and the second male mating part 12f to be respectively mated with the first female mating part 21b and the second female mating part 22f of the receptacle <NUM> at the predetermined radial contact pressures.

As shown in <FIG>, the insulator <NUM> of the plug <NUM> includes: the thick generally cylindrical first insulator part <NUM> exposed to the one side in the axial direction; and a thick cylindrical second insulator part <NUM> having a diameter approximately the same as that of the first insulator part <NUM> and disposed on the other side in the axial direction relative to the first insulator part <NUM>.

The one end face 31a of the first insulator part <NUM> projects more toward the one side in the axial direction than the external contact <NUM>. The one end face 31a of the first insulator part <NUM> makes surface contact with an end face 23a of the thick cylindrical insulator <NUM> and an end face 21a of the internal contact <NUM> in the receptacle <NUM> at a predetermined axial contact pressure so as to have an abutted engagement state.

The first insulator part <NUM> has a relative permittivity equivalent to that of the second insulator part <NUM>, which is an insulating part made of a resin. For example, the first insulator part <NUM> has a specific relative permittivity set within a relative permittivity range of about <NUM> to <NUM>, and is made of a material capable of being readily fixed to, or integrally molded with, the second insulator part <NUM>.

Furthermore, the first insulator part <NUM> is made of an elastic material capable of being elastically deformed at least in the radial direction of its generally cylindrical shape more easily than the second insulator part <NUM>.

More specifically, the first insulator part <NUM> is made of, for example, either an elastomer, such as silicon rubber, capable of being integrally molded with the second insulator part <NUM> by a liquid injection molding (LIM) method, or a synthetic resin elastic material, such as an elastomer, capable of being molded into a generally cylindrical shape as a single component and then being bonded and fixed to the second insulator part <NUM> via a known adhesive. In this case, the second insulator part <NUM> is made of a material suitable for the LIM method such as polycarbonate.

As shown in <FIG>, the second male mating part 12f of the external contact <NUM> in the plug <NUM> includes: a plurality of mating claw portions 12a disposed on the one side of the plug <NUM> in the axial direction and having a substantially divided cylindrical shape as a whole; and a supporting cylindrical portion 12b for integrally supporting the plurality of mating claw portions 12a at one ends thereof with a plurality of slits 12c being interposed between the plurality of mating claw portions 12a. The first insulator part <NUM> is disposed within a regional range closer to the one side in the axial direction than the supporting cylindrical portion 12b of the external contact <NUM>. The first insulator part <NUM> is fixed to one end face 32a of the second insulator part <NUM> on a base end side of the plurality of mating claw portions 12a.

The plurality of mating claw portions 12a of the second male mating part 12f include a plurality of protrusions 12d that projects in a radially outward direction at equiangular intervals within the same regional range in the axial direction on their tip side. The plurality of protrusions 12d as a whole form a protruded shape having a generally annular shape and having tapered guides provided before and behind the protrusions 12d. Such a protruded shape allows the plurality of mating claw portions 12a to be bent by a predetermined amount in a reduced-diameter direction in accordance with an inner diameter of the second female mating part 22f.

As shown in <FIG>, the first insulator part <NUM> includes an inwardly projecting part 31c having a diameter smaller than that of a central hole 31b in the vicinity of the one end face 31a. As shown in <FIG>, the first insulator part <NUM> is attached to the internal contact <NUM> with a stepped part 11c provided between the penetration part 11a of the internal contact <NUM> and the first male mating part <NUM>1b in the plug <NUM> being in abutment with the inwardly projecting part 31c of the first insulator part <NUM>.

With the use of the first insulator part <NUM> having any shape with a diameter slightly larger than an inner diameter D of the second male mating part 12f of the external contact <NUM>, a portion of the first insulator part <NUM> in the vicinity of the one end face 31a is brought into abutment with the stepped part 11c of the internal contact <NUM>, or the first insulator part <NUM> bulges out from the tip of the second male mating part 12f or into the plurality of slits 12c when the plurality of mating claw portions 12a of the second male mating part 12f are fitted into the second female mating part 22f. This reduces the application of a compressive load in the axial direction to the second insulator part <NUM> by the first insulator part <NUM>.

The one end face 32a of the second insulator part <NUM> projects toward the one side in the axial direction (the mating direction) from the supporting cylindrical portion 12b in the second male mating part 12f of the external contact <NUM> by a projecting length La (see <FIG> and <FIG>) significantly smaller than a length Lm (see <FIG>) from the base end to the tip of the plurality of mating claw portions 12a.

An axial length Lb (see <FIG>) of the first insulator part <NUM> is set to a value equal to, or slightly larger than, the mated depth Lf of the external contact <NUM> of the plug <NUM> into the receptacle <NUM>, and the one end face 31a of the first insulator part <NUM> projects more toward the one side in the axial direction than the external contact <NUM>.

As a result of such settings for the shape and dimensions of the first insulator part <NUM>, the first insulator part <NUM>, when the plurality of mating claw portions 12a of the second male mating part 12f are fitted into the second female mating part 22f, can be elastically recovered by following the plurality of mating claw portions 12a or can be bulged out into the plurality of slits 12c provided between the plurality of mating claw portions 12a after being compressed in the radial direction and the axial direction without compressing the second insulator part <NUM> in the radial direction.

Although the substantially divided cylindrical shape in the present embodiment refers to <NUM>-degree division (divided into quarters) having four mating claw portions 12a and four slits 12c, any plural number of divisions can be used.

As shown in <FIG>, widths w of the plurality of slits 12c in the circumferential direction of the external contact <NUM> of the plug <NUM> are equal to one another and substantially constant over the range of the length Lm from the base end to the tip of the plurality of mating claw portions 12a supported by the supporting cylindrical portion 12b. Note that the widths w of the plurality of slits 12c in the external contact <NUM> may be unequal to one another, or may be non-constant from the base end to the tip of the plurality of mating claw portions 12a.

As just described, the plug <NUM> and the receptacle <NUM> include the second male mating part 12f and the second female mating part 22f, which together create protrusion-recess mating with the mated depth Lf, in their external contacts <NUM> and <NUM>. The plug <NUM> and the receptacle <NUM> also include the first male mating part 11b and the first female mating part 21b, which together create protrusion-recess mating on an inner side of the receptacle <NUM> relative to the mated depth Lf, in their internal contacts <NUM> and <NUM>. The first female mating part 21b of the receptacle <NUM> has a recess depth larger than the length of the first male mating part 11b of the plug <NUM>, and an inner diameter slightly larger than the outer diameter of the first male mating part 11b.

In the thus configured present embodiment, early in the process of inserting the plug <NUM> into the receptacle <NUM> in the mating direction, the external contact <NUM> of the plug <NUM> initially mated with the second female mating part 22f of the receptacle <NUM> is bent in the radial direction.

At this time, the first insulator part <NUM> capable of being easily deformed elastically can facilitate elastic deformation and elastic recovery for the mating of the external contact <NUM> with the counterpart contact, and can effectively reduce the creation of a gap between the insulator <NUM> and the internal contact <NUM> or the external contact <NUM> after the elastic recovery of the external contact <NUM>. As the result, deterioration in characteristic impedance due to permittivity change resulting from the creation of such a gap space can be effectively reduced.

Moreover, when the second male mating part 12f of the plug <NUM> is mated with the second female mating part 22f of the receptacle <NUM> in the present embodiment, the plurality of mating claw portions 12a are bent in the radial direction to compress the first insulator part <NUM> and elastically recovered together with the first insulator part <NUM>. Thus, the operation of mating the plug <NUM> with the receptacle <NUM> can be facilitated, and the creation of a gap space between the insulator <NUM> and the internal contact <NUM> or the external contact <NUM>, which may lead to permittivity change, can be reduced more effectively.

Furthermore, since the first insulator part <NUM> has a relative permittivity equivalent to that of the second insulator part <NUM> in the present embodiment, deterioration in characteristic impedance in the mating parts of the plug <NUM> and the receptacle <NUM> in the connector <NUM> can be effectively reduced.

In addition, since the first insulator part <NUM> is integrally coupled to the second insulator part <NUM> in the present embodiment, the first insulator part <NUM> can be disposed at a stable position and with a stable orientation as well as in a required filled shape relative to the second insulator part <NUM>, the internal contact <NUM>, and the external contact <NUM> so as not to create a gap in the insulator layer.

Moreover, since the one end face 31a of the first insulator part <NUM> in the plug <NUM> projects more toward the one side in the axial direction than the external contact <NUM> of the plug <NUM>, the one end face 31a of the first insulator part <NUM> is brought into contact with the insulator <NUM> of the receptacle <NUM> earlier than the external contact <NUM>. Thus, the insulators <NUM> and <NUM> of the plug <NUM> and the receptacle <NUM> are disposed in a connected state via the first insulator part <NUM> provided therebetween without any gap not only in the radial direction but also in the axial direction.

As just described, the shape and orientation of the first insulator part <NUM> in the male-female mating state can be stably maintained, and contact between the internal contacts <NUM> and <NUM> of the plug <NUM> and the receptacle <NUM> as well as contact between the external contacts <NUM> and <NUM> thereof can be stably maintained in the present embodiment. Thus, deterioration in characteristic impedance of a transmission path due to capacitor change resulting from crush or clearance of the insulators <NUM> and <NUM> in the mating parts can be effectively reduced.

A connector <NUM> having the above-described configuration of the first embodiment was produced. In this connector <NUM>, the first insulator part <NUM> was made of silicon rubber, and the first insulator part <NUM> and the second insulator part <NUM> in the insulator <NUM> were integrally molded by the LIM method. The relative permittivity of each of the insulator <NUM> of the plug <NUM> and the insulator <NUM> of the receptacle <NUM> was set to <NUM>, and a characteristic impedance Z was set to <NUM>Ω. Measurements on propagation delay were made according to time-domain reflectometry (TDR).

<FIG> shows the result of the measurements via a graph having the vertical axis representing an impedance (Ω) and the horizontal axis representing a delay time (ps). The dotted line in <FIG> represents Example <NUM>, whereas the solid line represents Comparative Example <NUM> in which an insulator of a plug was made up solely of the same insulating material as the second insulator part <NUM> of Example <NUM>, and a gap necessary to permit bending upon the insertion of the plug was provided in the vicinity of an inner peripheral surface of the second male mating part 12f of the external contact <NUM>.

As is apparent from <FIG>, in both of Comparative Example <NUM> and Example <NUM>, a portion of a propagation delay time region corresponding to its transmission path length excluding a delay section corresponding to its connector mating part had a characteristic impedance of about <NUM>Ω. In the section corresponding to the connector mating part, in contrast, increase (pronounced increase especially in Comparative Example <NUM>) in characteristic impedance due to reflection occurred. The increase in characteristic impedance in Example <NUM>, however, was reduced to less than half of that in Comparative Example <NUM>.

Thus, it can be recognized that Example <NUM> having the first insulator part <NUM> capable of being easily deformed elastically in the radial direction as compared to the second insulator part <NUM> can provide a connector capable of effectively reducing deterioration in characteristic impedance of the transmission path.

<FIG> illustrate a connector according to a second embodiment useful for understanding the invention.

As shown in these figures, the second embodiment has a configuration generally the same as that of the above-described connector <NUM> of the first embodiment except for the configuration of a second male mating part 12f in an external contact <NUM> of a plug <NUM>.

A receptacle <NUM>, which is a female connector member, includes, as corresponding counterpart contacts, a first female mating part 21b to be mated with a first male mating part 11b of an internal contact <NUM> at a predetermined radial contact pressure, and a second female mating part 22f to be mated with the second male mating part 12f of the external contact <NUM> at a predetermined radial contact pressure.

As shown in <FIG>, in the second male mating part 12f of the external contact <NUM> according to the present embodiment, widths of a plurality of slits 12e are each set to have a larger width w2 on the base end side of a plurality of mating claw portions 12a supported by a supporting cylindrical portion 12b and to have a smaller width w1 on the tip side of the plurality of mating claw portions 12a.

Since a first insulator part <NUM> can be easily deformed elastically as compared to a second insulator part <NUM>, effects similar to those of the first embodiment can be obtained also in this embodiment.

Additionally, a required bending amount and strength of the plurality of mating claw portions 12a can be attained in the present embodiment without providing, for example, a hole to cause stress concentration in the plurality of mating claw portions 12a of the second male mating part 12f. Moreover, when the plurality of mating claw portions 12a are bent in the radial direction to compress the first insulator part <NUM>, the first insulator part <NUM> can be partially bulged out into the slits 12e on the base end side of the plurality of mating claw portions 12a. This makes it possible to reduce the creation of a gap space between an insulator <NUM> and the internal contact <NUM> or the external contact <NUM> more effectively while reliably permitting the required bending of the plurality of mating claw portions 12a. Furthermore, the application of a load to the second insulator part <NUM> can be reduced more effectively.

<FIG> illustrate a connector according to the present invention
As shown in these figures, the third embodiment has a configuration generally the same as that of the above-described connector <NUM> of the second embodiment except that the configuration of an internal contact <NUM> of a plug <NUM> differs from those in the above-described first and second embodiments, and the configuration of an external contact <NUM> is different from that in the above-described first embodiment but generally the same as that in the second embodiment. Note that the configuration of a receptacle <NUM>, which is a female connector member, is the same as those in the first and second embodiments.

As shown in <FIG>, in addition to a penetration part 11a that penetrates an insulator <NUM>, a first male mating part 11b projecting more toward one side in the axial direction than a first insulator part <NUM>, and a stepped part 11c provided between the penetration part 11a and the first male mating part 11b, the internal contact <NUM> of the plug <NUM> in this embodiment includes a protrusion 11d that protrudes in the radial direction toward the first insulator part <NUM> from the penetration part 11a at a position farther away from the first male mating part 11b than the stepped part 11c.

Since the first insulator part <NUM> can be easily deformed elastically as compared to a second insulator part <NUM>, effects similar to those of the first embodiment can be obtained also in this embodiment.

Additionally, even when the first insulator part <NUM> is brought into elastic abutment with an insulator <NUM> of the counterpart receptacle <NUM> upon the insertion of a plurality of mating claw portions 12a of a second male mating part 12f into a second female mating part 22f in the present embodiment, an axial displacement of the first insulator part <NUM> can be restricted by the protrusion 11d of the internal contact <NUM> in addition to, for example, the vicinity of one end face 31a of the first insulator part <NUM> abutting against, and thereby being held by, the stepped part 11c of the internal contact <NUM> as with the first and second embodiments. Thus, no gap is created, for example, in the portion where the insulators <NUM> and <NUM> abut against each other, and no large load is applied to the second insulator part <NUM>.

A connector <NUM> having the above-described configuration of the third embodiment was produced. In this connector <NUM>, the first insulator part <NUM> was made of silicon rubber, and the first insulator part <NUM> and the second insulator part <NUM> in the insulator <NUM> were integrally molded by the LIM method. The relative permittivity of each of the insulator <NUM> of the plug <NUM> and the insulator <NUM> of the receptacle <NUM> was set to <NUM>, and a characteristic impedance Z was set to <NUM>Ω. Measurements on propagation delay were made according to time-domain reflectometry (TDR).

<FIG> shows the result in comparison with Comparative Example <NUM> and Example <NUM> described above via a graph having the vertical axis representing an impedance (Ω) and the horizontal axis representing a delay time (ps). The alternate long and short dash line in <FIG> represents the result of Example <NUM>.

As is apparent from <FIG>, in all of Comparative Example <NUM>, Example <NUM>, and Example <NUM>, a portion of a propagation delay time region corresponding to its transmission path length excluding a delay section corresponding to its connector mating part had a characteristic impedance of about <NUM>Ω. In the section corresponding to the connector mating part, in contrast, increase (pronounced increase especially in Comparative Example <NUM>) in characteristic impedance due to reflection occurred as mentioned above. The increase in characteristic impedance in Example <NUM> was reduced to less than half of that in Comparative Example <NUM>, and the increase in characteristic impedance in Example <NUM> was reduced to about one-fifth of that in Comparative Example <NUM> (about half of that in Example <NUM>).

Thus, it can be recognized that Example <NUM> can also provide a connector capable of effectively reducing deterioration in characteristic impedance of the transmission path.

Although the insulator <NUM> of the plug <NUM> includes the first insulator part <NUM> in each of the above-described embodiments, the insulator <NUM> of the receptacle <NUM> may alternatively include a first insulator part made of an elastic material and exposed to the plug <NUM>, and a second insulator part disposed at a position farther away from the plug <NUM> than the first insulator part. In this case, it is also conceivable that the exposed end face of the first insulator part in the receptacle projects more toward the mating direction (one side in the axial direction) than the internal contact.

Moreover, when the internal contact and the external contact both have a cylindrical shape, an end face of the first insulator part filled between those contacts only needs to project more toward the front side in the mating direction than the contact disposed posteriorly in the mating direction of the internal and external contacts having different end face positions in the axial direction.

Furthermore, although the above-described embodiments each illustrate the internal and external contacts having circular cross-sectional shapes, the internal and external contacts may have non-circular cross-sectional shapes. Also, the material and cross-sectional shape of the first insulator part <NUM>, and the material and the like of the second insulator part <NUM> are not limited to those described above.

Claim 1:
A connector (<NUM>) comprising:
an internal contact (<NUM>) extending in an axial direction and disposed at an inner position in a radial direction;
an external contact (<NUM>) extending in the axial direction and disposed at an outer position in the radial direction; and
an insulator (<NUM>) disposed between the internal contact (<NUM>) and the external contact (<NUM>), wherein
at least one of the internal contact (<NUM>) and the external contact (<NUM>) includes, on one side in the axial direction, a mating part (11b, 12f) to be mated with a corresponding counterpart contact at a predetermined radial contact pressure,
the insulator (<NUM>) includes a first insulator part (<NUM>) exposed to the one side in the axial direction, and a second insulator part (<NUM>) disposed on the other side in the axial direction relative to the first insulator part (<NUM>), and the first insulator part (<NUM>) is made of an elastic material capable of being easily deformed elastically in the radial direction as compared to the second insulator part (<NUM>),
and
the internal contact (<NUM>) includes
a penetration part (11a) that penetrates the insulator,
a projecting end part (11b) that projects more toward the one side in the axial direction than the first insulator part (<NUM>), and
a protrusion (11d) that protrudes in the radial direction toward the first insulator part (<NUM>) from the penetration part (11a), characterized in that
one end face of the first insulator part (<NUM>) projects more toward the one side in the axial direction than the external contact (<NUM>).