Patent Publication Number: US-6666699-B2

Title: Coaxial connector and communication device having the same

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a coaxial connector and a communication device including a coaxial connector. 
     2. Description of the Related Art 
     Some mobile communication devices such as portable telephones, include a surface mount type coaxial connector that performs a switching function of changing a signal path is used. In conventional coaxial connectors, for the purpose of reducing the number of manufacturing steps, a resin insulating case, a fixed terminal, and a movable elastic terminal having a spring property are integrally formed by insert molding, whereby the number of elements of the device is reduced. 
     However, when the device elements are integrally formed, the unit costs thereof are high. The main reason is that the maintenance cost of the production facilities and tools such as metal molds is increased in order to maintain a high quality of the device elements that are integrally formed, inspection of the quality of the device elements must be carefully performed, the acceptance ratio of the integrally formed device elements is reduced, and so forth. Moreover, for integral molding, highly complicated 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 of μm, generation of resin burs at insert molding is a critical problem to be solved. 
     SUMMARY OF THE INVENTION 
     In order to overcome the problems described above, preferred embodiments of the present invention provide a high quality, low cost coaxial connector in which the number of manufacturing steps is greatly reduced, and a communication device having such a high quality, low cost coaxial connector. 
     According to a preferred embodiment of the present invention, a coaxial connector includes a first resin member having a concave portion into which a center contact of a mating coaxial connector is inserted, a second resin member for constituting an insulating case with the first resin member, a fixed terminal and a movable terminal fixed to one of the first resin member and the second resin 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, in which the fixed terminal and the movable terminal are sandwiched between the first resin member and the second resin member. 
     In the above-described configuration, the fixed terminal and the movable terminal are preferably separate components from the insulating cases, respectively. Thus, assembly of the various parts of the device can be carried out with less difficulty as compared with that of conventional assembly wherein the device elements are integrally formed by insert molding. Accordingly, the sum of the unit costs of the respective device elements is greatly reduced as compared with that of the conventional assembly parts. 
     Preferably, the coaxial connector has a structure in which the first resin member, the 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, during assembly of the coaxial connector having the above-described unique configuration, the device elements 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 device elements is increased, the number of production processes is prevented from being increased. Moreover, since the assembly and incorporation work of the device elements is carried out in one direction, the production efficiency is even more enhanced. 
     A communication device according to another preferred embodiment of the present invention includes the coaxial connector having the above-described structure. Thus, reduction of the cost and enhancement of the device qualities are achieved. 
     Other features, elements, characteristics, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention with reference to the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of a coaxial connector according to a preferred embodiment of the present invention; 
     FIG. 2 is a perspective view illustrating an assembling process of the coaxial connector shown in FIG. 1; 
     FIG. 3 is a side view illustrating manufacturing steps performed after the steps shown in FIG. 2; 
     FIG. 4 is a side view illustrating manufacturing steps performed after the steps shown in FIG. 3; 
     FIG. 5 is a perspective view illustrating manufacturing steps performed after the steps shown in FIG. 4; 
     FIG. 6 is a perspective view illustrating manufacturing steps performed after the steps shown in FIG. 5; 
     FIG. 7 is a perspective view illustrating manufacturing steps performed after the steps shown in FIG. 6; 
     FIG. 8 is a perspective view illustrating manufacturing steps performed after the steps shown in FIG. 7; 
     FIG. 9 is a perspective view illustrating manufacturing steps performed after the steps shown in 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 manufacturing steps performed after the steps shown in FIG. 9; 
     FIG. 12 is a perspective view illustrating manufacturing steps performed after the steps shown in 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 a preferred embodiment of a communication device of the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Hereinafter, preferred embodiments of a coaxial connector and a communication 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 a preferred embodiment of the present invention. Hereinafter, the details of the coaxial connector (coaxial receptacle)  1  of preferred embodiments of the present invention, together with the assembling procedures, will be described. The coaxial connector  1  preferably includes an insulating case preferably made of synthetic resin which includes a lower insulating case  2 A and an upper insulating case  2 B, a fixed terminal  21 , a movable terminal  31 , and an outer terminal (outer conductor)  41  which are preferably made of metal. 
     The lower insulating case  2 A preferably has a substantially rectangular shape. Guiding protuberances  3  for positioning the upper insulating case  2 B are provided preferably in the four corners on the upper surface (dividing plane) of the case  2 A, and rib receiving portions  4  for receiving the ribs  18  (see FIG. 2) of the upper insulating case  2 B are formed in the vicinity of the guiding protuberances  3 . The rib receiving portions  4  each have a concave plane shape, i.e., a reverse dome-shape (see FIG.  10 ). Moreover, substantially rectangular cuts  6  and  7  are formed in the centers of the two opposed sides of the lower insulating case  2 A, respectively. In the cut  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  7 . 
     The upper insulating case  2 B contains a substantially rectangular cover  11  and a columnar introduction portion  12  in the center of the upper surface 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 substantially circular cross-section. The introduction hole  13  elongates through the upper insulating case  2 B. The center contact of a mating coaxial connector protrudes 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 insulating case  2 B as shown in FIG.  2 . There ribs  18  are provided in order to position the fixed metallic terminal  21  and the movable terminal  31 . The tops of the ribs  18  have a C-shaped plane, so that the terminals  21  and  31  can be easily guided. A groove  15  having a substantially 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  extends. The groove  15  is elongated in a direction that is substantially perpendicular to the leading-out direction of the metallic fixed terminal  21 . The groove  15  prevents a flux contained in soldering paste from permeating into the insulating case. 
     The fixed terminal  21  is preferably formed by punching and bending a metallic flat sheet. The fixed terminal  21  includes a contact portion  22  that is in contact with the movable terminal  31 , a fixed portion  23  fixedly sandwiched between the insulating cases  2 A and  2 B, and a lead  24  that has a substantially L-shaped configuration. The contact portion  22  is preferably formed by bending both side portions thereof at a predetermined angle, and contains a horizontal plane  22   a  and inclined planes  22   b  on both of the sides of the horizontal plane  22   a.    
     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 insulating case  2 B, respectively, so that the fixed terminal  21  is incorporated in the upper insulating case  2 B with a high positional accuracy. Then, the upper insulating case  2 B is set in an assembly apparatus with the bottom surface thereof facing upward. In this case, the fixed terminal  21  is incorporated from the upper portion of the upper insulating case  2 B so that the horizontal surface  22   a  and the fixed portion  23  of the contact portion  22  come into close contact with the bottom of the upper insulating case  2 B. 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 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 surface  81   a  of the head chip  81  has a concave shape, such as a reversed dome shape. In this case, the head chip  81  is heated at a temperature at which the rib  18  can be sufficiently deformed thermally. 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 insulating case  2 B via thermally deformed dome-shaped ribs  18 . 
     The movable terminal  31  (see FIG. 1) is preferably formed by punching a metallic sheet having a spring property into a predetermined shape and size, and bending it. The movable terminal  31  is constructed to have a spring-movable function, and includes a movable contact portion  32  that contacts with the fixed terminal  21 , a fixed portion  33  fixedly sandwiched between the insulating cases  2 A and  2 B, and a lead  34  having a substantially L-shaped configuration. 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 provided 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 insulating case  2 B, respectively, as shown in FIG. 6, so that the movable terminal  31  is incorporated into the upper insulating case  2 B with a high positional accuracy. Then, the movable terminal  31  is incorporated from the upper portion of the upper insulating case  2 B in an assembly apparatus with the bottom portion of the case  2 B facing upward, so that the fixed portion  33  comes in close contact with the bottom of the upper insulating case  2 B. 
     Next, head chips  81  of the welder are pushed against the two ribs  18  positioning the movable terminal  31 , from the upper portion of the upper insulating case  2 B, using 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 insulating case  2 B via the ribs  18  which have been thermally deformed into a dome shape. Thus, the terminals  21  and  31  are fixed to the upper insulating case  2 B. 
     On the other hand, the outer terminal  41  (see FIG. 1) disposed to be in contact with the outer conductor of a mating coaxial connector is preferably formed by punching a metal sheet, e.g., made of brass, spring-use phosphor bronze, or other suitable material, bending, drawing, or other suitable process. A flat portion  42  in the center of the sheet body is arranged to cover the upper surface of the upper insulating case  2 B. Legs  43  are provided preferably in the four corners of the flat portion  42 , respectively. Moreover, in the center of the flat portion  42 , a substantially cylindrical through-hole portion  45  is arranged so as to be concentric with the columnar introduction portion  12  of the upper insulating case  2 B. The substantially 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 portion thereof facing upward. Then, the upper insulating case  2 B having the terminals  21  and  31  fixed thereto is conveyed to the upper portion of the outer terminal  41  with the bottom portion thereof facing upward. Moreover, from the upper direction of the external terminal  41 , the upper insulating case  2 B is overlaid and incorporated into the external terminal  41 . That is, the columnar introduction portion  12  of the upper insulating case  2 B is fitted into the substantially cylindrical through-hole portion  45  of the outer terminal  41 . Thereafter, as shown in FIG. 9, the lower insulating case  2 A is overlaid on the upper insulating case  2 B. 
     In FIG. 10, ordinarily, the size a of the upper insulating case  2 B is preferably smaller than the size b of the lower insulating case  2 A. The reason is that the working efficiency with which the lower insulating case  2 A is incorporated into the upper insulating case  2 B is greatly 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 have the relationship of a&lt;b, the incorporated lower insulating case  2 A becomes shaky, that is, the set position is unstable. Accordingly, in the first preferred embodiment of the present invention, the ribs  18  of the upper insulating case  2 B are preferably thermally deformed to have a domed shape, and also, the rib relief portions  4  of the lower insulating case  2 A are formed so as to have a reversed dome shape. That is, when the ribs  18  are combined with the rib receiving portions  4 , a self-alignment effect is achieved, so that the lower insulating case  2 A can be incorporated into the upper insulating case  2 B with high accuracy, and moreover, the shaky setting 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  2 A and  2 B are overlaid on each other as shown in FIG.  12 . Thereby, the structure of the assembly becomes rigid, firm and stable. 
     FIG. 13 is a perspective view of the coaxial connector  1  having a switching function, assembled as described above and viewed from the upper surface 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 arranged so as to be substantially on the same plane as the bottom of the lower insulating case  2 A. Thus, the coaxial connector  1  has a structure such that surface-mounting of components on the coaxial connector can be carried out. Moreover, in the outer terminal  41 , the substantially cylindrical through-hole portion  45  is arranged such that secure and stable connection to the mating coaxial connector is achieved. 
     As shown in FIG. 14, in the inner space of the insulating case defined by the combination of the insulating cases  2 A and  2 B, 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  2 A and  2 B, respectively. Thereby, the positions of the terminals  21  and  31  are determined with respect to the insulating cases  2 A and  2 B. Thus, the terminals  21  and  31  can be easily fixed with respect to the insulating cases  2 A and  2 B. Moreover, since the fixed terminal  21  and the movable terminal  31  are formed separately from the insulating cases  2 A and  2 B, respectively, the assembly and processing of the device elements can be achieved with less difficulty as compared with conventional device elements that are integrally formed by insert molding. Thus, the sum of the unit costs of the device elements  2 A,  2 B,  21 ,  31 , and  41  is much lower than that of the conventional device elements. 
     In production of the coaxial connector  1 , the respective assembled device elements  2 A,  2 B,  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 easily and accurately checked, respectively. Thus, rejected products can be detected much earlier in the respective processes, and the quality of the products is greatly improved. In addition, useless assembly of the rejected products is eliminated, so that the product cost can be reduced. Moreover, since the incorporation of the device elements  2 A,  2 B,  21 ,  31 , and  41  is carried out in one direction (from the upper direction), the production efficiency is even more improved. 
     Furthermore, the dome-shaped ribs  18  fix the terminals  21  and  31  and the upper insulating case  2 B before hand. Accordingly, in the case in which the terminals  21  and  31  are sandwiched between the lower insulating case  2 A and the upper insulating case  2 B, there is no danger that the terminals  21  and  31  are released or shifted from position, which may be 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 insulating case  2 B, 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, checking on the contact state between the contact portion  22  and the movable contact portion  32 , carried out after completion of the assembly, is greatly simplified. Thus, the number of processes can be reduced. As a result, the coaxial connector  1  which has very high quality and is inexpensive is provided. 
     Furthermore, in the first preferred embodiment, the respective device elements to be assembled  2 A,  2 B,  21 ,  31 , and  41  are fixed preferably 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 some other reason, it is not necessary to consider degradation of the chemical material. Accordingly, the production line facilities can be quickly re-started. 
     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 such that the center portion thereof rises upwardly, and thereby, the movable terminal contacts with the fixed terminal  21 , because of 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 is in the state that the movable contact portion  32  is bent 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 moves upward, as a result of 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 communication device according to a second preferred 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 preferred embodiment is preferably used. Thereby, e.g., when a telecommunications apparatus manufacture 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 present invention including the coaxial connector and the communication device is not limited to the preferred embodiments described above. The coaxial connector and the communication device can be modified within the scope of the sprit of the present invention. The ribs disposed on the insulating case may be provided on the upper insulating case  2 B as described in the above-described preferred embodiments, or may be provided on the lower insulating case  2 A. Moreover, as the outer profile of the insulating case and the shapes of the concave portions, optional shapes and sizes such as substantially rectangular and substantially circular shapes may be used as desired. 
     As seen in the above-description, according to preferred embodiments of the present invention, since the fixed terminal and the movable terminal are formed as device elements separate from the insulating cases, respectively, assembly and working of the device elements are achieved with less difficulty as compared with that of conventional device elements that are integrally formed by insert molding. Accordingly, the sum of the unit costs of the respective device elements is smaller than that of the conventional device elements. 
     Furthermore, a structure in which the first resin member, the second resin member, the fixed terminal, the movable terminal, the external terminal are overlaid on each other, is used. Thus, in production of the coaxial connector, the resin members and other device elements are overlaid and incorporated sequentially while the work pieces are sequentially conveyed. Accordingly, even though the number of device elements is increased, the number of production processes is decreased. Furthermore, since the finishing states of the work-pieces in the respective processes, rejected products can be detected much earlier in the respective processes. Thus, products having high qualities can be provided. In addition, the assembling of the device elements is carried out in one direction, and thereby, the production efficiency is even more improved. 
     While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made without departing from the spirit and scope of the present invention.