Coaxial electrical connector

The present invention relates to a coaxial electrical connector, especially a right angle coaxial electrical connector. As for the right angle electrical connector, the one disclosed in Patent Reference JP 2001-43939 is known.

As shown in Fig. 5, the connector 50 of the Patent Reference is fitted and connected onto the counter connector 60, which is arranged on a circuit board P, in the direction vertical to the circuit board. The counter connector 60 has a cylindrical outer conductor 61, a center conductor 62 arranged in the center of the outer conductor 61, and a dielectric 63 which is molded between those conductors as a unitary piece. The outer conductor 61 is formed to have a cylindrical shape by rolling and jointing two edges of a metal sheet piece. The outer conductor 61 has a locking groove 61A on the outer circumferential surface. The center conductor 62 has a rod-like contact section 62A, and a connecting section 62B which is formed as an L-shape arm extending from the lower end of the contact section 62A. The dielectric 63 is arranged only in lower portion of the counter connector 60. Above the dielectric 63, an annular receiving space is formed between the outer conductor 61 and the contact section 62A of the center conductor 62.

The outer conductor 51 of the connector 50 which is fitted and connected onto the counter connector 60 has a cylindrical fitting section 51A, a cover section 51B, a frame-like section 51C, and a cable holding section 51D. The outer conductor 51 is made by punching and bending a metal sheet to form the shape. As also shown in Fig. 6, the cylindrical fitting section 51A has a jointing section 51A1 at its upper half portion, and has a cylindrical shape. An annular protrusion 51E for locking the fitting of the connectors is provided on the inner surface of the cylindrical fitting section 51A by making an annular groove on the outer surface of the cylindrical fitting section 51A. A plurality of slits 51F is provided at the lower half portion of the cylindrical fitting section 51A along its circumferential direction, so as to cross the annular protrusion 51E. The frame-like section 51C is provided so as to protrude in the radial direction of the fitting section 51A from a part of the upper portion of the fitting section 51A.

The outer conductor 51 holds the dielectric 52, while the dielectric 52 holds a terminal 53, which is a center conductor of the connector 50. As shown in Fig. 6, the cover section 51B and the holding section 51D of the outer conductor 51 are provided opposite the frame-like section 51C in the radial direction, and extend upward from the upper edge of the cylindrical fitting section 51A. After the dielectric 52 and the terminal 53 which is already connected to a cable are held in the cylindrical fitting section 51A, the cover section 51B and the surrounding section 51D are bent downward for 90 degree, as shown in Fig. 5. The cover section 51B and the cylindrical fitting section 51A are connected via a narrow linking section 51G, where the cover section 51B is bent. The dielectric 52 holds the terminal 53, and has a terminal hole 52A to house spring contact sections 53A of the terminal 53. The dielectric 52 also has a tongue 52B which extends upward and can be bent at its base and a cable receiving section 52D having a cable guiding groove 52C. The tongue 52B is bent being pressed by the cover section 51B of the outer conductor 51, while it slides over the inner surface of the cover section 51B along the extending direction (longitudinal direction) of the tongue 52B.

In this connector 50, as shown in Fig. 6, after the core-wire C1 of the coaxial cable C is connected by soldering onto the upper surface of the terminal 53, the contact sections 53A of the terminal 53 are inserted into the terminal hole 52A of the dielectric 52. Then, the outer conductor 51 is bent at the linking section 51G while pushing the tongue 52B of the dielectric 52 (See Fig. 5), and then the holding section 51D is bent so as to tightly hold the frame-like section 51C and the cable C.

Once the connector 50 is fitted onto the counter connector 60, the contact sections 53A of the terminal of the connector 50 contact with the center conductor 62 of the connector 60 by pinching it. While the cylindrical fitting section 51A of the outer conductor 51 of the connector 50 enlarges its diameter, it contacts with the outer circumferential surface of the outer conductor 61 of the connector 60, and the connector 50 is locked not to come off by the fitting of the annular protrusion 51E to the annular locking groove 61A.

In the connector of the Patent Reference, when the tongue 52B of the dielectric 52 is bent being pushed by the cover section 51B of the outer conductor 51, since the inner surface of the cover section 51B is flat, the tongue 52B can slide obliquely over the inner surface of the cover section, as shown with the dashed line having one long dash and two short dashes in Fig. 7. The sliding off of the tongue can be occurred even by slight asymmetry in the strength of the tongue 52B, or by slight asymmetry in the pressure applied by the cover section. With those slight asymmetries, the tongue could unacceptably slide off. If the tongue is in a wrong position and pressed by the cover section, the tongue cannot be correctly placed in the groove on the upper surface of the main body of the dielectric, so that the cover section is held unstably above the intended position. In this case, the dimension of the connector in the height direction can be larger than the intended dimension, and also the holding of the tongue can be unstable. In some cases, the electrical properties of the connector can be deteriorated by the sliding off of the tongue.

Furthermore, the sizes of electrical devices have been dramatically reduced in these years, and in case of the connector, the dimension in the height direction, i.e. the dimension in the fitting direction, is required to be small. In case of the connector disclosed in the Patent Reference 1, however, since the inner surface of the cover section is flat, even if the tongue is correctly bent at the correct position without sliding off, the thicknesses of the cover section and the tongue are added above the main body of the dielectric, so that the profile of the connector cannot be reduced.

In view of the above problems, it is an object of this invention to provide a coaxial electrical connector, in which the tongue of the dielectric can be correctly bent without sliding off, and the profile of the connector is made small by reducing the total dimension of the tongue and the cover section in the height direction. The above object is achieved by the invention as recited in claim 1.

Embodiments of the invention will now be described by way of example with reference to the accomapanying drawings, in which: <ul id="ul0001" list-style="none"><li>Fig. 1 is a cross-sectional view, taken along the plane including the axis of the cable, of a coaxial electrical connector according to an embodiment of the invention when it is connected to a cable;</li><li>Fig. 2 is the perspective view of the connector of Fig. 1 in the process of assembling;</li><li>Fig. 3(A) is a sectional.view of the connector before the terminal is inserted therein;</li><li>Fig. 3(B) is a sectional view of the connector after the terminal is inserted therein but before the cover section is bent;</li><li>Fig. 3(C) is a sectional view of the connector after the cover section is bent and the portion is tightly held by the surrounding section and the holding section;</li><li>Fig. 3(D) is an elevational view as viewed from the right of Fig. 3(B) ;</li><li>Figs. 4(A)-4(E) are cross-sections of modifications of a tongue and a receiving or restricting section according to another embodiment of the invention;</li><li>Fig. 4(F) is a cross-section of the embodiment of Figs. 1 and 2 for comparison with Figs. 4(A)-4(E);</li><li>Fig. 5 is a cross-sectional view of the conventional connector and the counter connector before fitting;</li><li>Fig. 6 is an exploded perspective view of the outer conductor, dielectric and the center conductor as the terminal of the connector of Fig. 5 before assembling the connector;</li><li>Fig. 7 is an elevational view, as viewed from the cable side, of the outer conductor and the tongue of the dielectric disposed when the outer conductor of the connector of Fig. 6 is bent.</li></ul>

In Figs. 1-3, the coaxial connector 10 is to be connected to the counter connector 60 which is mounted onto a circuit board (See Fig. 1). This counter connector 60 is not a part of this invention, and is same as a conventional connector shown in Fig. 5. Therefore, same reference numerals are used for the same parts as in Fig. 5, and the explanation is omitted. The coaxial connector 10 of this embodiment which is to be connected to the counter connector 60 is so-called "right angle connector", in which the connector fits to the counter connector in the direction perpendicular to the extending direction of the cable. As shown in Figs. 1 and 2, this connector comprises an outer conductor 11; a dielectric 12 and a terminal 13 which is a center conductor.

The outer conductor 11 is formed by first forming the outer shape by punching and then bending a metal sheet, and has a cylindrical fitting section 14, arms 15, a cover section 16 and a surrounding section 17 as a unitary piece. The cylindrical fitting section 14 is formed by rolling a metal sheet to form the cylindrical shape, and has an opening 14A of a certain width on the circumferential wall, which is opened for placing a cable C (See Fig. 2). A locking section which engages with an annular locking groove 61A that is formed on the outer surface of the outer conductor 61 of the connector counter connector, is formed on the lower portion of the inner surface of the cylindrical fitting section 14 as an annular protrusion 14B (See Fig. 1) .

As shown in Fig. 2, a pair of flat arms 15 which extend from the opening 14A in the radial direction of the fitting section 14 and are parallel to each other, is formed at the upper half portion of the cylindrical fitting section 14. Narrowing sections 15B, which have smaller distance from each other than the distance between the arms 15, are formed at the boundary portions between the opening 14A and the arms 15. Preferably, the distance between the inner surfaces of the narrowing sections 15B is set as small as the minimum distance required to dispose the connecting section of the terminal that extends in the radial direction and the dielectric that supports the connecting section. Each narrowing section 15B directly extends from the circumferential wall of the cylindrical fitting section 14. In the height direction, i.e. the axial direction of the cylindrical fitting section 14, the arms 15 has larger dimension than the narrowing sections 15B so as to extend to a height level of the annular protrusion of the cylindrical fitting section 14B. Latching grooves 15A which are formed like dovetail grooves are formed at the upper edges of the arms, and are opened upward.

The cover section 16 and the surrounding section 17 extend via the linking section 18 from a part of the upper opened end of the cylindrical fitting section, which is opposite the opening 14A in the radial direction of the cylindrical fitting section. The surrounding section, the cover section, the linking section and the fitting section are formed together as a unitary piece. Once the cover section 16 is bent toward the cable C as shown in Fig. 2, the upper opened end of the cylindrical fitting section 14 is generally covered. The cover section 16 has shoulders 16A at the side edges, which are bent downward. Once the cover section is bent toward the fitting section, the shoulders 16A are placed outside of the cylindrical fitting section 14.

The outer conductor 11 has the surrounding section which extends from the cover section 16. The surrounding section 17 generally covers the arms in the extending direction of the cable, and forms a rectangular cylindrical shape which covers the arms in the width direction when the surrounding section 17 is bent toward the arms. In this embodiment, when the surrounding section 17 is bent so as to form the rectangular cylindrical shape, it partially covers the narrowing sections at its one end and covers a portion farther than the free ends of the arms at the other end. A space is formed between the narrowing sections 15B and the inner surface of the surrounding section.

A restricting concave section 19 is formed on the inner surface of the cover section 16 and the surrounding section 17. This restricting concave section 19 is formed thereon by punching without making a protrusion but keeping a flat surface on the outer surface of the cover section 16 and the surrounding section 17. Therefore, the thickness of the restricting concave section 19 is smaller than that of other portions of the cover section and the surrounding section. The restricting concave section 19 is formed to have a rectangular shape having its longitudinal direction along the extending direction of the cable, and partially houses the tongue of the dielectric, which will be described below, in the thickness direction. In this embodiment, the restricting concave section 19 is formed on the inner surface of the cover section 16 and the surrounding section 17. If the length of the tongue is short, the restricting concave section 19 can be formed only on the inner surface of the cover section 16. When the tongue is bent with the cover section, the restricting concave section 19 works as a section which restricts the sliding off of the tongue in the width direction. On the other hand, at the time of completing assembly of the connector, it works as a receiving section which places at least a part of the tongue therein in the thickness direction.

In addition, as shown in Fig. 1, a reinforcing section 16B is formed on the outer surface of the cover section, which is other than the area corresponding to the restricting concave section 19 (See Fig. 1). In this embodiment, the reinforcing section 16B is provided as an embossed section which is dented on the outer surface and protrudes on the inner surface. The reinforcing section 16B is provided to improve the strength of the cover section 16. By forming the reinforcing section near the restricting concave section, the reduction of the strength of the cover section caused by the formation of the restricting concave section 19 can be compensated. Preferably, the reinforcing section is formed outside the area that corresponds to the restricting concave section 19 but close to the restricting concave section 19, and extends in the direction vertical to the longitudinal direction (extending direction of the cable) of the restricting concave section 19, as shown in the embodiment in Fig. 1.

A holding section 20 to hold the cable C is provided from the end of the surrounding section opposite the cover section 16. The holding section 20 is formed to form a rectangular cylindrical shape similarly to the surrounding section 17 when it is bent, and comprises a first holding section 20A and a second holding section 20B (See Fig. 2). Those holding sections 20A and 20B have different dimensions in the width direction, so as to be capable of tightly holding the respective cable portions having different thickness. More specifically, the first holding section is designed to tightly hold the cable over the shielding wire (C2), and the second holding section 20B is designed to tightly hold the cable over its outer coating.

The dielectric 12 of the connector 10 is covered and held by the above-described outer conductor 11. The dielectric 12 is made by molding a plastic resin, which is an electric insulating material, and has a main body section 21, a tongue 22 and a cable receiving section 23 as a unitary piece. The lower part of the main body section 21 is shaped so as to be placed in the outer conductor 61 of the counter connector 60, and the upper part of the main body 21 is held by the outer conductor 11.

A hole 21A having a rectangular cylindrical shape is formed at the center part of the main body 21 to receive the contact section of the terminal that will be described below. In addition, the dielectric 12 has the cable receiving section 23 which extends in the extending direction of the cable from the upper portion of the main body 21. Side surfaces of the cable receiving section are formed along the inner surfaces of the arms 15 of the outer conductor 11, and the lower surface of the cable receiving section 23 is formed so as to be along the surrounding section 19 when it is bent to cover the portion. The cable receiving section 23 is designed to have a space in the height direction to receive the connecting section of the terminal, the cable and the tongue 22. In addition, since the dimensions of the connecting section of the terminal and the core-wire C1 of the cable C to be connected to the connecting section are different in the height direction, a step-like section 23A to receive the core-wire C1 is formed partially on the upper surface of the cable receiving section 23. On the lower surface of the cable receiving section 23, a groove 23B, into which the outer conductor 61 of the counter connector can be placed, is formed. A positioning step-like section 21B is formed on the upper surface of the main body 12 of the dielectric 12, being slightly closer to the cable in the cable's extending direction than the step-like section 19A of the restricting concave section 19 which is formed on the inner surface of the cover section 16.

As shown in Fig. 2, the tongue 22 is formed as a flat piece extending upward being adjacent to the linking section 18 of the outer conductor 11. The tongue 22 has a suitable width to be housed in the restricting concave section 19 which is formed on the inner surface of the cover section 16 and the surrounding section 17 of the outer conductor 11. When the cover section 16 is bent at the linking section 18, the tongue 22 is bent with the cover section being pushed by the cover section 16, and placed in the restricting concave section 19.

In addition, the dielectric 12 has latching protrusions 26 which engage with the latching grooves 15A being pressed from their upper sides into the latching groove formed on the arms 15 of the outer conductor 11.

As shown in Fig. 1, the terminal 13 has a connecting section 24 which is generally flat and extends along the extending direction of the cable C, and has a pair of flat contact sections 25 which extend downward along the fitting direction of the connectors from the connecting section 24. The connecting section 24 extend to almost near the end of the tongue 22 after bent, and tightly held between the tongue 22 and the upper surface of the main body 21 of the dielectric 12. The whole range of the connecting section 24 is covered in the extending direction by the tongue 33 of the dielectric 12. The connecting section 24 has a thinner portion, which is formed by punching, on the lower surface of its end where the connecting section is connected to the core-wire of the cable C.

The connecting section 24 also has a small part of angled section 24A at the middle part of the terminal, corresponding to the positioning step-like section 21A of the main body 21 of the dielectric 12 (See Fig. 1). As shown in Fig. 1, the angled section 24A is formed, so as to correspond to the positions of the step-like section 19A of the restricting section 19 and the positioning step-like section 21A. In addition, by providing such angled section 24A, the connecting section 24 has a shape similar to that of the inner surface of the cover section 16 of the outer conductor 11 which has the restricting concave section 19 thereon, so that the distance between the inner surface of the cover section 19 and the connecting section 24 can be generally same through the connecting section, and the electrical properties can be satisfactorily maintained. Moreover, the connecting section 24 of the terminal is angled upward toward the cable side by the angled section 24A, and under the angled section, the main body of the dielectric has a groove 23B for receiving the upper_edge of the outer conductor 61 of the counter connector 60. Therefore, without increasing the height of the connector, the groove 23B can be made deep. In addition, the angle of the angled section 24A can be any, and can be almost 90 degrees. The distance between the pair of the contact sections 25 is set to tightly press the rod-like contact section 62A of the center conductor 62 of the counter connector 60.

The procedure for assembling and how to use the above-described connector are described below. <ul id="ul0002" list-style="none"><li>(1) First, the core-wire C1 of the cable C, which is exposed at the end by removal of the outer coating and so on, is connected by soldering to the connecting section 24 of the terminal 13. This connection by soldering is done at the lower surface of the end portion of the connecting section, which is dented and has a smaller thickness (See Fig. 3 (A)) .</li><li>(2) Next, as shown in Fig. 3(A), after or before the connection described in (1), the dielectric 12 is placed onto the outer conductor 11. More specifically, the main body 21 and the cable receiving section 22 of the dielectric 12 are placed in the cylindrical fitting section 14 and between the pair of arms, respectively. The latching protrusions 26 formed on the side surfaces of the cable receiving section 23 are pressed in the latching grooves 15A (See Fig. 2). At this time, the tongue 22 of the dielectric 12 and the cover section 16 of the outer conductor 11 are not bent yet, therefore still extend upward.</li><li>(3) Thereafter, as shown in Fig. 3(B), the contact sections 25 of the terminal 13 is inserted and arranged in the hole 21A formed on the main body of the dielectric 12. This arrangement of the contact sections 25 into the hole 21A can be done outside the outer conductor 11 before placing the dielectric onto the outer conductor 11. At this time, the core-wire C1 of the cable can be soldered to the connecting section 24.</li><li>(4) Next, as shown in Fig. 2, the cover section 16 and the surrounding section 17 of the outer conductor 11 are bent at the linking section in the direction of the arrow A, so as to be bent toward the cable C (See Fig. 3 (C)) . At the time of bending, the tongue 22 of the dielectric 12 is placed in the restricting concave section 19, which is formed on the inner surface of the cover section 16 and the surrounding section 17 of the outer conductor 11. Therefore, the movement of the tongue in the width direction is restricted but it slides on the lower surface of the restricting concave section along the longitudinal direction.</li><li>(5) Once the cover section 16 and the surrounding section 17 are completely folded by bending at the linking section 18, the cover section 16 covers the upper portion of the cylindrical fitting section 14 of the outer conductor 11, and the surrounding section 17 covers the cable C held in the cable receiving section 23, and the holding section 20 contacts with the cable. In addition, the cover section 16 and the surrounding section 17 hold the terminal via the tongue 22.</li><li>(6) Thereafter, the surrounding section 17, the first holding section 20A and the second holding section 20B are bent so as to surround the cable and the other portions. The surrounding section 17 securely surrounds and holds the arms 15, the cable receiving section 22 of the dielectric 12 disposed between the arms 15, the end of the tongue 22, and the connecting section 24 of the terminal together. The first holding section 20A and the second holding section 20B tightly hold the cable C over the shielding wire portion C2 and over the outer coating, respectively. Once the cover section is bent as described above, the angled section 24 of the connecting section 24 of the terminal 13 is pressed obliquely toward the positioning step-like section 21A of the dielectric 12 by the step-like section 19A of the cover section 16. Therefore, the terminal 13 slightly moves toward the cable side and the angled section 24A contacts with the positioning step-like section 21A. Accordingly, the positioning of the terminal 13 is done by using the positioning step-like section 21A as the reference position. In other words, the contact section 25 of the terminal 13 is accurately positioned with regard to the rod-like contact section 62A of the center conductor 62 of the counter connector 60 in the extending direction of the cable.</li><li>(7) As shown in Fig. 1, the connector assembled as described above is fitted and connected to the counter connector 60. By fitting those connectors, the terminal 13 of the center conductor of the connector 10 elastically contacts with the contact sections 62A of the center conductor 62 of the counter connector 60 at its contact section 14. In addition, the outer conductor 61 of the counter connector 61 is placed in the annular space between the cylindrical fitting section 14 of the outer conductor 11 and the dielectric 12 of the connector 10. The diameter of the annular protrusion 14B provided on the inner surface of the outer conductor 11 is enlarged by contacting with the upper edge of the outer conductor 61 of the counter connector 60, so that the connector 10 can be fitted to the counter connector 60. The diameter of the outer conductor 11 is elastically enlarged mainly around the narrowing sections 15B of the cylindrical fitting section 14, enlarging the distance between the narrowing sections 15B. Since the narrowing sections are provided being a certain distance away from each other, the enlargement of the outer conductor 11 which is required for the fitting of the connectors can be achieved without dramatically enlarging the distance between the narrowing sections. Accordingly, the circular shape of the cylindrical fitting section 14 will not be deformed so much. Therefore, the elasticity required for enlarging the diameter of the cylindrical fitting section 14 can be easily achieved and the rigidity for maintaining the shape is secured. After the elastic deformation, the annular protrusion 14B of the cylindrical fitting section 14 engages with the locking groove 61A of the counter connector 60.</li></ul>

It should be understood that the present invention is not limited by the embodiment illustrated in the drawings, and can be altered or modified within its scope. For example, the receiving section or the restricting section formed on the cover section and the surrounding section of the outer conductor and the tongue of the dielectric are not limited to the ones illustrated in Figs. 1 and 2. Possible embodiments are shown in Figs. 4(A)-4(E). Here, the tongue and the surrounding section before bending are shown in each figure, taken along a plane vertical to the longitudinal direction of the tongue.

In Fig. 4(A), the tongue 22 is the same as the one in Fig. 2, but the restricting section 19B is formed as protrusions so as to restrict the movement of the tongue in the width direction by the edges. In addition, in Fig. 4 (B) , the restricting section 19B is formed similarly to the restricting concave section 19 of Fig. 2, but a protrusion 19C formed on the outer surface of the surrounding section 17, corresponding to the concave section 19.

In Fig. 4(C), the tongue 22 has a concave section 22A on the center part of the upper surface in the width direction, and a protrusion 19D is formed on the inner surface of the surrounding section corresponding to the concave section 22A. In Fig. 4(D), the cross-section of the tongue has convex-curved shape, while the restricting concave section 19 has a concave-curved shape corresponding to the convex shape of the tongue 22. In Fig. 4(E), the tongue 22 has a convex cross section and has a small protrusion 22B, and the restricting concave section 19 has a tapered hole to receive the protrusion 22B. Here, Fig. 4 (F) illustrates the embodiment of Figs. 1 and 2 for comparison with Figs. 4(A)-(E).

In any of Figs. 4(A)-(E), the tongue and the receiving section or the restricting section restricts the sliding off of the tongue in the width direction, and maintain the correct position of the tongue. In some of those examples, a part of the tongue is placed in the section in the thickness direction. Such restriction of the movement of the tongue does not have to be applied to the whole tongue, but can be applied partially.