Abstract:
A cable includes: a signal core module including a pair of inner conductors and an inner insulative layer enclosing the inner conductors, the inner conductors extending parallel to each other, the inner insulative layer forming a spacing region between said inner conductors; a grounding core arranged beside the signal core module; and a metal shielding layer enclosing the signal core module and the grounding core.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
       [0001]    The present invention relates to a cable having a pair of individually insulated signal cores for transmission of high-speed signals. 
       2. Description of Related Arts 
       [0002]    A high-speed signal cable typically includes a pair of signal cores, on or two ground wires, a metal shield around the cores and the ground wire or wires, and an insulated sheath outside the metal shield. Each of the pair of signal cores includes an inner insulating layer and an inner conductor coated by the inner insulating layer. The inner conductor and the inner insulation layer of each signal core are integrated with each other. The two signal cores are arranged side by side and wrapped in the metal shield. 
         [0003]    U.S. Pat. No. 6,273,753, issued on Aug. 14, 2001, discloses a flat flexible cable assembly including a plurality of twins coaxial wires. Each wire includes two conductors, an insulating layer wrapping the two conductors, a metal braid covering the insulating layer, and a cable jacket. 
         [0004]    U.S. Patent Application Publication No. 20150221415, published on Aug. 6, 2015, discloses a shielded electrical cable of which one exemplary embodiment shows a conductor set including two individually insulated conductors or two jointly insulated conductors. 
       SUMMARY OF THE INVENTION 
       [0005]    An object of the present invention is to provide a cable with a stable electrical properties. 
         [0006]    To achieve the above-mentioned object, a cable comprises: a signal core module including a pair of inner conductors and an inner insulative layer enclosing the inner conductors, the inner conductors extending parallel to each other, the inner insulative layer forming a spacing region between said inner conductors; a grounding core arranged beside the signal core module; and a metal shielding layer enclosing the signal core module and the grounding core. 
         [0007]    According to the present invention, the cable has a signal core module with an inner insulative layer one-time molded on the two inner conductor to have a stable electrical characteristic. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0008]      FIG. 1  is A schematic view of a high-speed signal cable in the prior art; 
           [0009]      FIG. 2  is a schematic view of another high-speed signal cable in the prior art; 
           [0010]      FIG. 3  is a schematic view of a cable in accordance with present invention; and 
           [0011]      FIG. 4  is a schematic view of the signal core module of the cable as shown in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0012]    Reference will now be made in detail to a preferred embodiment of the present invention. 
         [0013]    Referring to  FIGS. 1 to 2 , a high-speed signal cable  100  having a single grounding core  1  is shown in  FIG. 1 . A high-speed signal cable  200  having a pair of grounding cores  2  is shown in  FIG. 2 . Each of the high-speed signal cable  100  and the high-speed signal cable  200  includes a pair of signal cores  3  for transmitting differential signals, a metal shielding layer  5  enclosing the signal cores  3 , and an outer insulative layer  6 . Each of the signal cores  3  includes an inner conductor  31  and an inner insulative layer  32  enclosing the inner conductor  31 . The two inner insulating layers  32  of the two signal cores  3  are respectively molded to cover the corresponding inner conductors  31 . 
         [0014]    Referring to  FIG. 3 , a cable in accordance with a performed embodiment of the present invention includes a signal core module  301 , a pair of grounding cores  302 , a metal shielding layer  303  enclosing the signal core module  301  and the grounding cores  302  and a outer insulative housing  304  enclosing the metal shielding layer  303 . The metal shielding layer  303  is made of aluminum foil material. 
         [0015]    Referring to  FIG. 4 , the signal core module  301  includes a pair of inner conductors  310  side by side arranged with each other along a transverse direction and each extending along a front-to-back direction perpendicular to the transverse direction, and an inner insulative layer  320  formed at the periphery of the two inner conductors  310  in a molding, with the inner conductors  310  extend parallel to each other in the axial direction of the cable  300 . The inner insulative layer  320  forms a spacing region  330  in a central area thereof between the inner conductors  310 , and the spacing region  330  has a certain width between the inner conductors  310 . The cross section of the signal core module  301  includes two parallel opposing straight edges, an arcuate edge connected between the ends of the same side of the two straight sides, and an arcuate edge connected between the ends of the opposite side of the two straight sides, and the combinations of the straight edges and the arcuate edges are over the smooth transition of its outer surface. The inner conductors  310  is a metallic material and may be a material such as copper or aluminum, and the inner insulating layer  320  may be made of an insulating material. 
         [0016]    In the present embodiment, the cable  300  includes a pair of grounding cores  302 , and each of them is arranged on two opposite sides of the signal core module  301  respectively, being arranged in a straight line in a radial direction of the cable  300 . The distance of the pair of inner conductors  310  is basically equal to the distance of the grounding cores  302  from the inner conductors  310 . The grounding cores  302  are electrically connected with the metal shielding layer  303 , and then common ground. In other embodiments, the cable  300  may have one or more grounding cores  302 , and the arrangement may also be adjusted as desired. 
         [0017]    In the present embodiment, the distance between the left and right sides of the outer insulative layer  304  in a vertical direction is smaller than the distance from the middle portions of the outer insulative layer  304  in the vertical direction. 
         [0018]    The two inner conductors  310  of the signal core module  301  of the utility model cable  300  are once formed within the unitary inner insulative layer  320 , so that the process of the cable  300  is simplified and has a relatively stable electrical characteristic due to the relative positions of the inner conductors  310  are fixed, so that the cable  300  according to the present invention has a high degree of safety. On the other hand, once to unify the two respective insulative layers together, it may reduce the distance between the two inner conductors. For example, as shown in  FIG. 2 , in the conventional core module the inner insulative layer  32  may provide a thickness A to surround the corresponding inner conductor  31 , thus resulting in a distance  2 A between the two inner conductor  31 . Differently, as shown in  FIG. 4 , in the invention, even though the inner insulative layer  320  provides a thickness A enclosing the transverse outer (one half) side of the corresponding inner conductor  310 , i.e., the transverse outer 180-degree range with regard to the inner conductor  31 , the distance between the two inner conductors  310  may be arranged/reduced to be less than  2 A, thus minimizing the whole transverse dimension of the cable. It is noted that the cable defines a cross-sectional configuration essentially composed of a rectangular area with two opposite triangular areas symmetrically located at two opposite transverse sides of the, respectively, wherein the rectangular area is supportably filled with the insulative layer  320  while a space is formed between the inner insulative layer  320  and the grounding core  302  in the triangular area to confront the shielding layer  303 . Generally speaking, the shielding layer  303  is intimately supported by the inner insulative layer  320  in the vertical direction perpendicular to both the transverse direction and the front-to-back direction, while being spaced from the inner insulative layer  320  in the transverse direction. 
         [0019]    It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.