Patent Publication Number: US-2023142379-A1

Title: Connector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of PCT International Application No. PCT/JP2021/023259, filed on Jun. 18, 2021, which claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2020-115360, filed on Jul. 3, 2020. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a connector suited for transmission of high frequency signals. 
     BACKGROUND 
     In the transmission of high frequency signals, reflection of the signal or the like easily occurs, and realizing satisfactory transmission characteristics becomes a concern. In particular, satisfactory transmission characteristics over a wide band of high frequency is required for the transmission of video signals. 
     JP 8-222325A discloses an invention in which flat coaxial cable ends, where a plurality of coaxial cables are gathered, are collectively connected to a circuit ground and a frame ground by way of a common electrically conductive member. The invention of JP 8-222325A aims to eliminate the occurrence of potential variation and occurrence of impedance discontinuity of the ground side wiring. 
     There is a need for a connector having satisfactory transmission characteristics over a wide band of high frequency. 
     SUMMARY 
     A connector includes a housing having an accommodation space with an opening on a front surface facing a mating connector side and a rear surface facing away from the mating connector side, an outer shell covering the housing including the rear surface of the housing, a contact accommodated in the accommodation space, and an inner shell positioned in the accommodation space and covering the contact. A spring portion that elastically presses the inner shell forward is provided between a portion of the outer shell along the rear surface of the housing and the inner shell. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described by way of example with reference to the accompanying Figures, of which: 
         FIG.  1    is an isometric view of a connector according to an embodiment of the invention; 
         FIG.  2    is an exploded isometric view of the connector of  FIG.  1   ; 
         FIG.  3 A  is an isometric view showing the connector in a direction in which a lower surface appears; 
         FIG.  3 B  is a rear view of the connector; 
         FIG.  4 A  is a sectional side view taken along arrow A-A of  FIG.  1   ; 
         FIG.  4 B  is a sectional perspective view taken along arrow A-A of  FIG.  1   ; 
         FIG.  5 A  is a side view of a front shell and a back shell of the connector, where the back shell abuts on the front shell; 
         FIG.  5 B  is a side view of the front shell and the back shell, with a slight gap formed between the back shell and the front shell; 
         FIG.  5 C  is graph of a measurement result of an insertion loss; 
         FIG.  5 D  is a graph of a measurement result of a voltage standing wave ratio; 
         FIG.  6 A  is a side view of the front shell and the back shell of the connector, where the back shell abuts on the front shell; 
         FIG.  6 B  is a side view of the front shell and the back shell, with a slight gap formed between the back shell and the front shell; 
         FIG.  6 C  is a graph of a measurement result of an impedance; 
         FIG.  6 D  is a graph is a measurement result of screening attenuation characteristics; 
         FIG.  7 A  is a side view of an inner shell according to another embodiment with the back shell in an open posture; and 
         FIG.  7 B  is a side view of the inner shell with the back shell in a pushed state against the front shell. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIG.  1    is an isometric view of a connector according to one embodiment of the invention. 
     The connector  1  is a connector in which a forward side indicated with an arrow F is directed toward a mating connector to be mated with the mating connector. Furthermore, the connector  1  is mounted on a circuit board positioned on a lower side indicated with an arrow Z and soldered to the circuit board. 
       FIG.  2    is an exploded isometric view of the connector, whose isometric view is illustrated in  FIG.  1   . As shown in  FIG.  2   , the connector  1  includes an outer housing  10  and an outer shell  20 . 
     The outer housing  10  is formed with an accommodation space  11 . The accommodation space  11  is formed with an opening on a front surface facing the mating connector side (facing the direction of the arrow F) and the rear surface facing away from the mating connector. The outer housing  10  corresponds to an example of a housing in the invention. 
     In an embodiment, the outer shell  20  is provided for shielding, and has a shape that covers an upper surface, left and right side surfaces, and a rear surface of the outer housing  10 . The outer shell  20  is provided with a plurality of pin-shaped solder connecting portions  21  extending downward to be solder connected to the circuit board. 
     As shown in  FIG.  2   , the connector  1  includes a front shell  30 , a front housing  40 , a pin  50 , a back housing  60 , and a back shell  70 . 
     The pin  50 , also referred to as a contact, includes a first extended portion  51  extending in a front-back direction, and a second extended portion  52  bent and extended downward from a back end of the first extended portion  51 . The first extended portion  51  comes into contact with and electrically conducts with a contact of a mating connector mated with the connector  1 . The second extended portion  52  is solder-connected to a circuit board positioned below. The pin  50  corresponds to an example of a contact in the present invention. 
     The front housing  40  and the back housing  60  support the pin  50  so as to sandwich the pin  50  from the front side and the back side. A configuration combining the front housing  40  and the back housing  60  in the present embodiment corresponds to an example of an inner housing of the invention. 
     In an embodiment, the front shell  30  and the back shell  70  cover the pin  50  with the front housing  40  and the back housing  60  in between, and shield the pin  50 . The front shell  30  is formed with six pin-shaped solder-connecting portions  31  extended downward and solder-connected to the circuit board. In the present embodiment, a configuration combining the front shell  30  and the back shell  70  corresponds to an example of an inner shell in the present invention. 
     An assembly including the front shell  30 , the front housing  40 , the pin  50 , the back housing  60 , and the back shell  70  is referred to as a “sub-assembly  80 ”, shown in  FIG.  2   . The sub-assembly  80  is inserted into a main housing  10  from a rear surface side of the main housing  10 . The sub-assembly  80  is inserted into the main housing  10 , and the outer shell  20  is placed thereon to complete the connector  1  shown in  FIG.  1   . 
       FIG.  3 A  shows the second extended portion  52  of the pin  50 , a plurality of solder-connecting portions  21  of the outer shell  20 , and a plurality of (six) solder-connecting portions  31  of the front shell  30 . Among them, the second extended portion  52  of only one pin  50  is for signal transmission. The other plurality of solder-connecting portions  21  of the outer shell  20  and the six solder-connecting portions  31  of the front shell  30  are for fixing the connector  1  to the circuit board, and are also for electrically grounding. In particular, eight portions, the two solder-connecting portions  21   a  of the plurality of solder-connecting portions  21  of the outer shell  20  and the six solder-connecting portions  31  of the front shell  30 , are responsible for grounding. Such eight solder-connecting portions  21   a ,  31  are positioned to surround the second extended portion  52  of the pin  50 . 
       FIG.  3 B  shows a raised piece  22 , which is a feature of the present embodiment. The raised piece  22  corresponds to an example of a spring portion and an example of a raised piece in the present invention. The raised piece  22  is provided in a region facing the rear surface of the outer housing  10  of the outer shell  20 , and has a shape raised toward the front side, that is, in a direction of an arrow F shown in  FIGS.  1  and  2   . Furthermore, the spring portion can be configured with a simple structure by providing such a raised piece  22  regardless of whether the raised piece  22  is on the outer shell  20  or on the inner shell  30 . 
     The operations of the raised piece  22  will be described below with reference to  FIG.  4   . The raised piece  22  is elastically bent by abutting on the inner shell  30 . The raised piece  22  abuts on the inner shell  30  at a position below the first extended portion  51  in an up-down direction. 
     The inner shell  30  has a shape of covering the contact  50 . Therefore, the position of the center of gravity of the inner shell  30  in the up-down direction is at a position below the first extended portion  51 . Thus, the entire inner shell  30  can be pressed forward in a balanced manner by abutting the raised piece  22  at a position below the first extended portion  51  in the up-down direction than by abutting the raised piece  22  at a position the same height as or above the first extended portion  51 . 
     As shown in  FIGS.  4 A and  4 B , the raised piece  22  is raised at an angle of 45° with respect to the up-down direction in the present embodiment so as to collapse forward (direction of the arrow F shown in  FIGS.  1  and  2   ). Then, a distal end portion  22   a  of the raised piece  22  butts against the back shell  70 . In  FIGS.  4 A and  4 B , the raised piece  22  is shown so as to bite into the back shell  70 , but this is to show the shape before deformation in design as is. In fact, the raised piece  22  butts against the back shell  70  and elastically deforms, and pushes the back shell  70  forward (direction of the arrow F). The back shell  70  is pushed by the raised piece  22 , and abuts on the front shell  30  so as not to form even a slight gap with the front shell  30 . In another embodiment, the raised piece  22  is raised at an angle smaller than 45° with respect to the up-down direction. 
     The raised piece  22  abuts on the back shell  70  at a position below the first extended portion  51  extending in the front-back direction of the pin  50  in the up-down direction. Since the second extended portion  52  of the pin  50  extends downward from the first extended portion  51 , the back shell  70  is also greatly spread toward the lower side from the first extended portion  51 , and the center of gravity of the back shell  70  is located on the lower side of the first extended portion  51 . Therefore, the entire back shell  70  is pushed against the front shell  30  in a balanced manner by abutting the raised piece  22  on the back shell  70  at a position below the first extended portion  51 . 
     In the present embodiment, the spring portion in the present invention can be realized with a simple structure by forming such raised piece  22 . 
       FIGS.  5 A- 6 D  show experiment results. 
       FIGS.  5 A and  6 A  show the front shell  30  and the back shell  70  in a state where the back shell  70  is abuts on the front shell  30 , and corresponds to one example of the invention.  FIGS.  5 B and  6 B  show the front shell  30  and the back shell  70  in a state where the raised piece  22 , shown in  FIGS.  4 A and  4 B , does not exist and a slight gap G is formed between the back shell  70  and the front shell  30 . The embodiment shown in  FIGS.  5 B and  6 B  corresponds to a comparative example with respect to the present invention. 
       FIG.  5 C  is a graph showing a measurement result of an insertion loss (dB). The insertion loss (dB) may be closer to 0 dB, and an example in which the back shell  70  is in contact with the front shell  30  is more satisfactory in a high frequency region, in particular, 2.0 to 3.0 GHz as compared with a comparative example in which the back shell  70  is not in contact with the front shell  30 . 
     Furthermore,  FIG.  5 D  is a graph showing a measurement result of a voltage standing wave ratio (VSWR) on the circuit board side. The voltage standing wave ratio (VSWR) may be closer to 1, and the example of  FIG.  5 A  is more satisfactory particularly in the high frequency region. 
       FIG.  6 C  is a graph of a measurement result of an impedance on the circuit board side. The impedance may be always stable at 50 ohm, and the example of  FIG.  6 A  is more satisfactory regarding the impedance. In addition,  FIG.  6 D  is a graph showing a measurement result of screening attenuation characteristics. The screening attenuation characteristics may be low, and the example of  FIG.  6 A  is more satisfactory regarding the screening attenuation characteristics as well. 
     The connector  1  of the present embodiment forms the raised piece  22  on the outer shell  20 , and pushes the back shell  70  forward to push the back shell  70  against the front shell  30 . Thus, the connector  1  of the present embodiment realizes satisfactory signal transmission characteristics as compared with a case where the raised piece  22  does not exist. 
     In the present embodiment, the raised piece  22  is raised at an angle of 45° with respect to the up-down direction. Thus, in the present embodiment, the balance between the signal transmission characteristics and the ensuring of the pressing force of the back shell  70  against the front shell  30  is maintained. 
     However, the raised piece  22  does not necessarily need to be raised at an angle of 45°. For example, the raised piece  22  may be raised at an angle smaller than 45° with respect to the up-down direction. The raised piece  22  abuts on the back shell  70  at a position of the pin  50  where the second extended portion  52  extending in the up-down direction exists in the height direction. When raised at an angle smaller than 45°, the raised piece  22  approaches to be parallel to the second extended portion  52  of the pin  50  as compared with a case where the raised piece is raised at an angle of 45°. Therefore, further improvement in the signal transmission characteristics can be expected. 
     Alternatively, the raised piece  22  may be raised at an angle larger than 45°. In this case, the spring force can be increased and the back shell  70  can be pushed stronger than when the raised piece  22  is raised at an angle of 45°. Therefore, the back shell  70  can be strongly pushed against the front shell  30 , and the back shell  70  and the front shell  30  can be more strongly adhered. 
     Furthermore, in the present embodiment, the raised piece  22  is provided on the outer shell  20 . The raised piece  22  is a raised piece that is raised obliquely toward the front side and elastically bent by abutting on the back shell  70 . However, in place of the raised piece  22 , a raised piece that is provided on the back shell  70  and raised toward the back side, and elastically bent by abutting on the outer shell  20 , may be provided. In the case of such a configuration as well, the back shell  70  can be elastically pushed against the front shell  30 . 
     The inner shell  90  is considered to have a structure of being separated into a plurality of portions or being partially separated even if connected to one portion in terms of the necessity of positioning the contact  50  on the inner side and covering the contact  50 . In this case, the inner shell  90  may be partially formed with a gap, described below, when pressing is not carried out or may be formed with a portion that is not sufficiently in contact. 
     In the connector  1 , the spring portion  22  is provided, and the inner shell  90  is elastically pressed forward. Therefore, even with the inner shell  90  having a structure in which the gap is formed when pressing is not carried out or a portion that is not sufficiently in contact is formed, the gap is filled or sufficient contact is obtained, and satisfactory transmission characteristics over a wide band of high frequency is realized. 
       FIGS.  7 A and  7 B  show an inner shell  90  according to another embodiment Here, for the sake of easy understanding, a portion corresponding to the front shell  30  and the back shell  70  in the embodiment described above in the inner shell  90  is referred to as the front shell  30  and the back shell  70  herein. 
     Even when the inner shell  90  having the structure shown in  FIG.  7    is adopted, the structure of each portion other than the inner shell  90  follows those in the embodiment described above. 
     The inner shell  90  shown in  FIGS.  7 A and  7 B  includes the front shell  30  and the back shell  70 , which are separated from or partially coupled to each other. Thus, with the inner shell  90  including the front shell  30  and the back shell  70 , which are of a partially coupled structure, the number of components are reduced as compared with when the front shell and the back shell are separated from each other, which is advantageous in terms of assembly and cost. The front shell  30  and the back shell  70  cover the contact  50  to sandwich the contact  50  from front side and back side. 
     The contact  50 , as well as an inner housing including the front housing  40  and the back housing  60  that supports the contact  50 , need to be inserted inside the inner shell  90 . Thus, at the time point of insertion, the back shell  70  is set to an open posture as shown with a chain line in  FIG.  7 A  with respect to the front shell  30 . After the contact  50  and the inner housing (front housing  40  and back housing  60 ) are inserted, the back shell  70  is in a posture indicated with a solid line in  FIG.  7 A . If the back shell  70  remained in the posture indicated with the solid line, the gap G tends to remain and is formed between the front shell  30  and the back shell  70 . 
     The back shell  70  is pressed forward by the raised piece  22  (see  FIGS.  3  and  4   ), so that the back shell  70  is pushed against the front shell  30 .  FIG.  7 B  shows the inner shell  90  in a pushed state. This pushing electrically integrates the front shell  30  and the back shell  70 , and satisfactory signal transmission characteristics as shown in  FIGS.  5  and  6    can be obtained.