Coaxial connector and communication device having the same

Abstract: A coaxial connector (1) comprises a synthetic resin insulating case composed of an underside insulating case (2A) and an upper side insulating case (2B) into which the insulating case is divided, a metallic fixed terminal (21), a movable terminal (31), and an external terminal (41). The terminals (21,31,41) are fixed to the upper insulating case (2B) by heat welding before hand. Thereafter, the solid portions of the terminals are sandwiched between the insulating cases (2A,2B). Incorporation work of these insulating cases and the terminals is carried out in one direction.

Description: BACKGROUND OF THE INVENTION 1. Field of the Intention The present invention relates to a coaxial connector and a communications device having the coaxial connector. 2. Description of the Related Art In some mobile communications devices such as portable telephones or the like, a surface mount type of coaxial connector having a switching function of changing a signal path is used. Conventionally, in the coaxial connector, for the purpose of reducing the number of production processes, a resin insulating case, a fixed terminal, and a movable terminal having a spring property are integrally formed by insert molding, whereby the number of assembly parts is reduced. However, as regards assembly parts integrally formed, the unit costs thereof are high in general. The main reasons lie in that the maintenance cost of the production facilities such as metal molds is increased to maintain the quality of the assembly parts integrally formed at a high level, inspection of the quality of the assembly parts is required to be severely carried out, the acceptance ratio of the assembly parts is reduced, and so forth. Moreover, for the integral molding, high techniques are needed. Especially, in the case of small-sized, low-height coaxial connectors for which it is required to have a dimensional tolerance of several tens µm, generation of resin burrs at insert molding is an important problem to be solved. However, EP 0 782 219 discloses a switching type connector that includes a spring contact that resiliently contacts a rigid contact. The spring contact is resiliency displaced when a plug of an external antenna is inserted into the connector. The pre-characterizing portion of claim 1 is based on EP-A-0 782 219. SUMMARY OF THE INENTION Accordingly, it is an object of the present invention to provide a coaxial connector in which the number of production processes can be reduced, and which has a high quality and is inexpensive, and a communications device having the same. To achieve the above object, there is provided a coaxial connector comprising: a first casing member having a concave portion into which a center contact of a mating coaxial connector is inserted; a second casing member for constituting an insulating case with the first casing member; a fixed terminal and a movable terminal provided for one of the first casing member and the second casing member; and an external terminal mounted on the outside of the insulating case and electrically connected to an outer conductor of the mating coaxial connector, wherein the fixed terminal and the movable terminal are sandwiched between the first casing member and the second casing member; characterized in that: the first and second casing members are resin members; the fixed terminal and movable terminal are fixed to said one of the first casing member and second casing member; and the movable terminal includes laterally extending portions by which the movable terminal is fixed, each fixed portion having a concave cutout formed therein. In the above-described configuration, the fixed terminal and the movable terminal are formed as assembly parts separated from the insulating cases, respectively. Thus, working of the parts can be carried out with less difficulty as compared with that of conventional assembly parts integrally formed by insert molding. Accordingly, the sum of the unit costs of the respective assembly parts can be reduced as compared with that of the conventional assembly parts. Preferably, the coaxial connector has the structure in which the first resin member, second resin member, the fixed terminal, the movable terminal, and the external terminal are overlaid on each other, and assembling of the first resin member, the second resin member, the fixed terminal, the movable terminal, and the external terminal is carried out in one direction. Preferably, in production of the coaxial connector, with the above-described configuration, the assembly parts such as the terminals, the resin members, and so forth are overlaid on each other sequentially to be incorporated while the work pieces are sequentially conveyed. Accordingly, even if the number of assembly parts is increased, the number of production processes can be suppressed from increasing. Moreover, since the incorporation work of the assembly parts is carried out in one direction, the production efficiency is more enhanced. The communications device of the present invention includes the coaxial connector having the above-described structure. Thus, reduction of cost and enhancement of quality can be achieved. The above and other features and advantages of the present invention will become clear from the following description of preferred embodiments thereof, given by way of example, with reference to the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an exploded perspective view of a coaxial connector according to an embodiment of the present invention; Fig. 2 is a perspective view illustrating assembling procedures of the coaxial connector shown in Fig. 1; Fig. 3 is a side view illustrating procedures succeeding those of Fig. 2; Fig. 4 is a side view illustrating procedures succeeding those of Fig. 3; Fig. 5 is a perspective view illustrating procedures succeeding those of Fig. 4; Fig. 6 is a perspective view illustrating procedures succeeding those of Fig. 5; Fig. 7 is a perspective view illustrating procedures succeeding those of Fig. 6; Fig. 8 is a perspective view illustrating the procedures succeeding those of Fig. 7; Fig. 9 is a perspective view illustrating procedures succeeding those of Fig. 8; Fig. 10 is a partial cross sectional view illustrating self-alignment effects between the insulating cases; Fig. 11 is a perspective view illustrating procedures succeeding those of Fig. 9; Fig. 12 is a perspective view illustrating procedures succeeding those of Fig. 11; Fig. 13 is a perspective view showing the appearance of the coaxial connector of Fig. 1; Fig. 14 is a cross sectional view of the coaxial connector shown in Fig. 12; Fig. 15 is a cross sectional view showing a mating coaxial connector fitted onto the coaxial connector of Fig. 12; and Fig. 16 is a block diagram showing an embodiment of a communications device of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a coaxial connector and a communications device having the coaxial connector in accordance with the present invention will be described with reference to the accompanying drawings. Fig. 1 is an exploded perspective view showing the constitution of a coaxial connector according to an embodiment of the present invention. Hereinafter, the details of the coaxial connector (coaxial receptacle) 1 of the present invention, together with the manufacturing/assembly procedures, will be described. The coaxial connector 1 comprises an insulating case made of synthetic resin which is divided into an underside insulating case 2A and an upper side insulating case 2B, a fixed terminal 21, a movable terminal 31, and an outer terminal (outer conductor) 41 which are made of metal. The underside insulating case 2A has a substantially rectangular shape. Guiding protuberances 3 for positioning the upper side insulating case 2B are provided in the four corners on the upper face (dividing plane) of the case 2A, and relief portions 4 for accommodating the ribs 18 (see Fig. 2) of the upper side insulating case 2B are formed in the vicinity of the guiding protuberances 3. The rib relief portions 4 each have a concave plane shape, namely, a reverse dome-shape (see Fig. 10). Moreover, rectangular cut-outs 6 and 7 are formed in the centers of the two opposed sides of the underside insulating case 2A, respectively. In the cut-out 6, the lead 24 of the fixed terminal 21 is received. On the other hand, the lead 34 of the movable terminal 31 is received in the cut-out 7. The upper side insulating case 2B contains a substantially rectangular cover 11 and a columnar introduction portion 12 in the center of the upper face of the cover 11. The columnar introduction portion 12 is opened in a cone-shape in the upper portion thereof, and has an introduction hole 13 having a circular cross-section. The introduction hole 13 extends through the upper side insulating case 2B. The center contact of a mating coaxial connector intrudes into the introduction hole 13 from the cone-shaped opening side. Moreover, the columnar ribs 18 are provided in the four corners on the bottom (dividing plane) of the upper side insulating case 2B as shown in Fig. 2. These ribs 18 are formed in order to position the fixed metallic terminal 21 and the movable terminal 31. The tops of the ribs 18 are worked so as to have a C-shaped plane, so that the terminals 21 and 31 can be easily guided. A groove 15 having a V-shaped cross section is formed between the introduction hole 13 and the side of the fixed terminal 21 from which the fixed terminal 21 is led out. The groove 15 is elongated perpendicularly to the leading-out direction of the metallic fixed terminal 21. The groove 15 has a function of preventing a flux contained in soldering paste from permeating into the insulating case. The fixed terminal 21 is formed by punching and bending a metallic flat sheet. The fixed terminal 21 comprises a contact portion 22 as a contact with the movable terminal 31, a fixed portion 23 fixedly sandwiched between the insulating cases 2A and 2B, and the lead 24 which is bent in an L-shape. The contact portion 22 is formed by bending both side portions thereof at a predetermined angle, and contains a horizontal plane 22a and inclined planes 22b on both of the sides of the horizontal plane 22a. The fixed portion 23 is provided with half-circular concavities 26 on both of the sides thereof. The concavities 26 are fitted onto the ribs 18 of the upper side insulating case 2B, respectively, so that the fixed terminal 21 is incorporated in the upper side insulating case 2B with a high positional accuracy. Then, the upper side insulating case 2B is set in an assembly apparatus with the bottom side thereof being faced upward. In this case, the fixed terminal 21 is incorporated from the upper side of the upper side insulating case 2B so that the horizontal face 22a and the fixed portion 23 of the contact portion 22 come into close contact with the bottom of the upper side insulating case 2B. A gap is formed between the fixed terminal 21 and the groove 15 which intersect each other. Then, as shown in Fig. 3, the head chip 81 of a welding device is lowered from the upper side of each of the ribs 18 positioning the fixed terminal 21 to be pushed against the rib 18. Fig. 3 is a side view of the coaxial connector taken in the direction indicated by arrow K in Fig. 2. The top face 81 a of the head chip 81 has a concave shape, namely, has a reversed dome shape. In this case, the head chip 81 is heated at a temperature at which the rib 18 can be deformed thermally sufficiently. Accordingly, as shown in Fig. 4, the rib 18 is thermally deformed by the top 81 a of the head chip 81 into a dome shape. Thereafter, the head chip 81 is elevated. Similarly, the other rib 18 for positioning the fixed terminal 21 is thermally deformed into a dome shape. Thus, as shown in Fig. 5, the fixed terminal 21 is heat welding-fixed to the bottom of the upper side insulating case 2B by means of the thermally deformed dome-shaped ribs 18. The movable terminal 31 (see Fig. 1) is formed by punching a metallic sheet having a spring property into a predetermined shape and size, and bending it. The movable terminal 31 is formed so as to have a spring-movable function, and comprises a movable contact portion 32 as a contact with the fixed terminal 21, a fixed portion 33 fixedly sandwiched between the insulating cases 2A and 2B, and a lead 34 bent into an L-shape. The movable contact portion 32 is bent so as to rise upward into an arc shape. Spring supports 37 are provided on both of the ends of the movable contact portion 32, and a spring contact portion 38 is formed in the center thereof. Half-circular concavities 36 are formed on both of the sides of the fixed portion 33. The concavities 36 are fixed onto the ribs 18 of the upper side insulating case 2B, respectively, as shown in Fig. 6, so that the movable terminal 31 is incorporated into the upper side insulating case 2B with a high positional accuracy. Then, the movable terminal 31 is incorporated from the upper direction of the upper side insulating case 2B set in an assembly apparatus with the bottom side of the case 2B facing upward, so that the fixed portion 33 comes in close contact with the bottom of the upper side insulating case 2B. Next, head chips 81 of the welder are pushed against the two ribs 18 positioning the movable terminal 31, from the upper direction of the upper side insulating case 2B, in the same procedures as described in reference to Figs. 3 and 4, so that the ribs 18 are thermally deformed into a dome shape. Thus, as shown in Fig. 7, the movable terminal 31 is heat welding-fixed to the bottom of the upper side insulating case 2B by means of the ribs 18 thermally deformed into a dome shape. Thus, the terminals 21 and 31 are fixed to the upper side insulating case 2B. On the other hand, the outer terminal 41 (see Fig. 1) to be in contact with the outer conductor of a mating coaxial connector is formed by punching a metal sheet, e.g., made of brass, spring-use phosphor bronze, or the like, bending, drawing, or the like. A flat portion 42 in the center of the sheet body is made to cover the upper face of the upper side insulating case 2B. Legs 43 are formed in the four corners of the flat portion 42, respectively. Moreover, in the center of the flat portion 42, a cylindrical through-hole portion 45 is formed so as to be concentric with the columnar introduction portion 12 of the upper side insulating case 2B. The cylindrical through-hole portion 45 is fitted onto the outer conductor of the mating coaxial connector. Ordinarily, the outer terminal 41 functions as a ground. The outer surface of the outer terminal 41 is plated, if necessary. As shown in Fig. 8, the outer terminal 41 is set on an assembly apparatus with the bottom side thereof being faced upward. Then, the upper side insulating case 2B having the terminals 21 and 31 fixed thereto is conveyed to the upper position of the outer terminal 41 with the bottom side thereof being faced upward. Moreover, from the upper direction of the external terminal 41, the upper side insulating case 2B is overlaid and incorporated into the external terminal 41. That is, the columnar introduction portion 12 of the upper side insulating case 2B is fitted into the cylindrical through-hole portion 45 of the outer terminal 41. Thereafter, as shown in Fig. 9, the underside insulating case 2A is overlaid on the upper side insulating case 2B. In Fig. 10, ordinarily, the size a of the upper side insulating case 2B is set to be smaller than the size b of the underside insulating case 2A. The reason lies in that the working efficiency with which the underside insulating case 2A is incorporated into the upper side insulating case 2B is improved. Fig. 10 is a partial cross sectional view of the coaxial connector taken in the direction X-X in Fig.9. However, if the sizes a and b are set so as to have the relation of a< b, the incorporated underside insulating case 2A becomes shaky, that is, the phenomenon occurs in which the set position is unstable. Accordingly, in the first embodiment of the present invention, the ribs 18 of the upper side insulating case 2B are thermally deformed to have a domed shape, and also, the rib relief portions 4 of the underside insulating case 2A are formed so as to have a reversed dome shape. That is, when the ribs 18 are combined with the rib relief portions 4, a self-alignment effect is produced, so that the underside insulating case 2A can be incorporated into the upper side insulating case 2B with a high accuracy, and moreover, the shaky set position can be prevented (see Fig. 11). Next, the legs 43 of the outer terminal 41 are caulked from the upper direction to obtain an assembly having the structure in which the terminals 21 and 31 and the insulating case 2A and 2B are overlaid on each other as shown in Fig. 12. Thereby, the structure of the assembly becomes stiff. Fig. 13 is a perspective view of the coaxial connector 1 having a switching function, assembled as described above and viewed from the upper face direction thereof. In the coaxial connector 1, the top portions of the leads 24 and 34 of the terminals 21, 31, and 41, and the legs 43 are formed so as to be substantially on the same plane as the bottom of the underside insulating case 2A. Thus, the coaxial connector 1 has such a structure that surface-mounting of the coaxial connector can be carried out. Moreover, in the outer terminal 41, the cylindrical through-hole portion 45 is formed, so that secure, stable connection to the mating coaxial connector can be achieved. As shown in Fig. 14, in the inner space of the insulating case formed by the combination of the insulating cases 2A and 2B, the fixed terminal 21 and the movable terminal 31 are arranged so that the fixed terminal 21 lies on the movable terminal 31. Regarding the fixed terminal 21 and the movable terminal 31, the fixed portions 23 and 33 are sandwiched between the insulating cases 2A and 2B, respectively. Thereby, the positions of the terminals 21 and 31 are determined with respect to the insulating cases 2A and 2B. Thus, the terminals 21 and 31 can be easily fixed with respect to the insulating cases 2A and 2B. Moreover, since the fixed terminal 21 and the movable terminal 31 are formed as assemby parts separated from the insulating cases 2A and 2B, respectively, working of the parts can be achieved with less difficulty as compared with conventional assembled parts integrally formed by insert molding. Thus, the sum of the unit costs of the assembled parts 2A, 2B, 21, 31, and 41 becomes lower than that of the conventional parts. In production of the coaxial connector 1, the respective assembled parts 2A, 2B, 21, 31 and 41 are overlaid on each other and incorporated sequentially while the work pieces are being sequentially fed. Accordingly, the finishing states of the work pieces in the respective processes can be checked, respectively. Thus, rejected products can be earlier detected in the respective processes, and the quality of the products can be enhanced. In addition, useless assembly of the rejected products is eliminated, so that the product cost can be reduced. Moreover, since the incorporation of the assembled parts 2A, 2B, 21, 31, and 41 is carried out in one direction (from the upper direction), the production efficiency can be more improved. Furthermore, the dome-shaped ribs 18 fix the terminals 21 and 31, and the upper side insulating case 2B beforehand. Accordingly, in the case in which the terminals 21 and 31 are sandwiched between the underside insulating case 2A and the upper side insulating case 2B, there is no danger that the terminals 21 and 31 are released or shifted from the terminals 21 and 31, which are caused by vibration or impact while the parts are conveyed in the production facilities. Moreover, the sizes of the contact portion 22 of the fixed terminal 21 and the movable contact portion 32 of the movable terminal 31 are relatively small. Therefore, it is a large factor in enhancement of the mechanical performance (the spring performance of the movable contact portion 32) of the coaxial connector 1 that the contact positions of the contact portion 22 and the movable contact portion 32 are accurately determined. In the coaxial connector 1, after the terminals 21 and 31 are heat-welded to the upper side insulating case 2B, the contact position between the contact portion 22 and the movable contact portion 32 can be checked. Therefore, a deficiency in contact between the contact portion 22 and the movable contact portion 32 can be detected during assembly. Thereby, check on the contact state between the contact portion 22 and the movable contact portion 32, carried out after completion of the assembly, can be simplified. Thus, the number of processes can be reduced. As a result, a coaxial connector 1 of high quality and which is inexpensive can be provided. Furthermore, in the first embodiment, the respective assembly parts 2A, 2B, 21, 31, and 41 are fixed by heat welding and caulking, not using a chemical material such as an adhesive, a solder, or the like. Accordingly, in the case in which the production line facilities are stopped for a moment for maintenance or the like, it is not necessary to consider degradation of the chemical material. Accordingly, the production line facilities can be quickly worked again. Hereinafter, operation of the coaxial connector 1 will be described with reference to Figs. 14 and 15. As shown in Fig. 14, when no mating coaxial connector is mounted, the movable contact portion 32 is in the state that the center portion thereof uses upwardly, and thereby, the movable terminal 31 gets into contact with the fixed terminal 21, attributed to the spring property of the movable contact portion 32. Thus, both of the terminals 21 and 31 are electrically connected to each other. On the other hand, as shown in Fig. 15, when the mating coaxial connector is mounted, the center contact 65 of the mating coaxial connector inserted through the introduction hole 13 provided on the upper side pushes the center portion of the movable contact portion 32 downward so that the center portion is inverted and gets into the state that it extends downward into an arc shape. Thereby, the spring contact portion 38 of the movable terminal 31 is released from the contact portion 22 of the fixed terminal 21, so that the electrical connection between the fixed terminal 21 and the movable terminal 31 is interrupted, while the center contact 65 and the movable terminal 31 are electrically connected to each other. Simultaneously, the outer conductor (not shown) of the mating coaxial connector is fitted onto the outer terminal 41, so that the outer conductor and the outer terminal 41 are electrically connected to each other. When the mating coaxial connector is removed from the coaxial connector 1, the center portion of the movable contact portion 32 is restored to the state that the center portion rises upward, utilizing the spring property. Thereby, the fixed terminal 21 and the movable terminal 31 are electrically connected to each other again, while the electrical connection between the center contact 65 and the movable terminal 31 is interrupted. Hereinafter, a portable telephone as an example of a communications device according to a second embodiment of the present invention will be described. Fig. 16 shows an electric circuit block diagram of the RF circuit portion of a portable telephone 120. In Fig. 16, an antenna 122, a diplexer 123, a change-over switch 125, a transmission side isolator 131, a transmission side amplifier 132, a transmission side inter-stage band-pass filter 133, a transmission side mixer 134, a reception side amplifier 135, a reception side inter-stage band-pass filter 136, a reception side mixer 137, a voltage control oscillator (VCO) 138, and a local band-pass filter 139 are shown. Here, as the change-over switch 125, the coaxial connector 1 of the first embodiment can be used. Thereby, e.g., when a set maker checks the electrical characteristics of the RF circuit portion during the manufacturing process of the portable telephone 120 as an example, a measuring probe (mating coaxial connector) 126 connected to a meter, is fitted onto the coaxial connector 1. Thereby, the signal path from the RF circuit portion to the antenna 122 can be changed to the signal path from the RF circuit portion to the meter. When the measuring probe 126 is removed from the coaxial connector 1, the signal path is returned to the signal path from the RF circuit portion to the antenna 122. Thus, a portable telephone 120 having a high reliability can be realized by mounting the coaxial connector 1. The coaxial connector and the communications device having the same of the present invention are not limited to the above embodiments, and can be differently modified within the scope of the present invention as defined in the annexed claims. The ribs formed on the insulating case may be provided on the upper side insulating case 2B as described in the above-described embodiments, or may be provided on the underside insulating case 2A. Moreover, as the outer profile of the insulating case and the shapes of the concave portions, optional shapes and sizes such as rectangular and circular shapes may be selected in compliance with specifications. As seen in the above description, according to the present invention, since the fixed terminal and the movable terminal are formed as assembly parts separated from the insulating cases, respectively, working of the parts can be achieved with less difficulty as compared with that of conventional assembly parts integrally formed by insert molding. Accordingly, the sum of the unit costs of the respective assembly parts is smaller than that of the conventional assembly parts. Furthermore, the structure is employed in which the first resin member, the second resin member, the fixed terminal, the movable terminal, the external terminal are overlaid on each other, the assembly parts such as the terminals. Thus, in production of the coaxial connector, the resin members, or the like are overlaid and incorporated sequentially while the work pieces are sequentially conveyed. Accordingly, even though the number of assembly parts is increased, the number of production processes can be suppressed. Furthermore, since the finishing states of the work-pieces in the respective processes, rejected products can be earlier detected in the respective processes. Thus, high quality products can be provided. In addition, the assembling of the assembly parts is carried out in one direction, and thereby, the production efficiency can be more improved.

Claims: A coaxial connector comprising: a first casing member (2B) having a concave portion (13) into which a center contact of a mating coaxial connector is inserted; a second casing member (2A) for constituting an insulating case with the first casing member; a fixed terminal (21) and a movable terminal (31) provided for one of the first casing member (2B) and the second casing member (2A); and an external terminal (41) mounted on the outside of the insulating case and electrically connected to an outer conductor of the mating coaxial connector, wherein the fixed terminal (21) and the movable terminal (31) are sandwiched between the first casing member (2B) and the second casing member (2A); characterized in that : the first and second casing members (2B,2A) are resin members; the fixed terminal (21) and movable terminal (31) are fixed to said one of the first casing member (2B) and second casing member (2A); and the movable terminal (31) includes laterally extending portions (33) by which the movable terminal is fixed, each fixed portion (33) having a concave cutout (36) formed therein. A coaxial connector according to claim 1, wherein the coaxial connector has the structure in which the first casing member (2B), the second casing member (2A), the fixed terminal (21), the movable terminal (31), and the external terminal (41) are overlaid on each other, and assembling of the first casing member (2B), the second casing member (2A), the fixed terminal (21), the movable terminal (31), and the external terminal (41) is carried out in one direction. A communications device including the coaxial connector as set forth in claim 1 or 2.

Inventors: URATANI CHIKARA, URATANI, CHIKARA, Uratani, Chikara, c/o (A170) I. P. Department
Applicants: MURATA MANUFACTURING CO, MURATA MANUFACTURING CO., LTD.
Application year: 2001
Main classification: H01R13
IPC codes: H01R13, H01R24, H01R103