Patent Publication Number: US-2012034825-A1

Title: Connection terminal for high-voltage cable

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of International Application No. PCT/CN2010/072219, filed Apr. 26, 2010, designating the United States of America, which claims priority to Chinese Patent Application No. 200920131244.8, filed on Apr. 30, 2009 to State Intellectual Property Office, PRC, the entire contents of both of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a terminal, more particularly to a connection terminal of a high-voltage cable. 
     BACKGROUND OF THE INVENTION 
     At present, high-voltage terminals have been widely used and developed, especially on pure electric or hybrid vehicle systems. The difference of a pure electric or hybrid vehicle from a traditional fuel vehicle lies in that the pure electric or hybrid vehicle needs high-voltage cables to transmit high-current and high-voltage power. Waterproof insulation of the high-voltage terminal has been a difficult problem for the manufacturers. 
     SUMMARY OF THE INVENTION 
     The present disclosure is provided to solve at least one problem as mentioned above. Accordingly, a connection terminal of a high-voltage cable is provided, which can overcome the problem of high cost and low quality in the art. Furthermore, the insulating and waterproof performance can be greatly enhanced. 
     According to an aspect of the disclosure, a connection terminal of a high-voltage cable is provided. The connection terminal may comprise a connector having a connecting end and a free end connected with the connecting end; a cable having a conductive core and an insulating layer surrounding the conductive core. The conductive core may be coupled to the free end of the connector. The connection terminal may further comprise: a first plastic layer surrounding at least a part of the free end of the connector and at least a part of the insulating layer; and a second plastic layer surrounding at least a part of the first plastic layer and at least a part of the free end of the connector. 
     According to an embodiment of the disclosure, the second plastic layer may be formed with at least a groove or at least a protrusion on an outer surface of the second plastic layer where the first and second surrounding layers are overlap with each other. 
     According to another embodiment of the disclosure, the entire connector is covered by the second plastic layer with the connecting end exposed to the outside. 
     According to another embodiment of the present disclosure, a pair of plastic layers are formed at the connecting portion between the insulating layer of the cable and the connector. Waterproof and insulation properties will be thus enhanced largely, which not only reduces the manufacturing cost but also increases high temperature resistance and high pressure resistance. 
     Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The aforementioned features and advantages of the invention as well as additional features and advantages thereof will be more clearly understood hereinafter as a result of a detailed description of embodiments when taken in conjunction with the drawings, in which: 
         FIG. 1  shows a schematic view of a connection terminal according to an embodiment of the disclosure; 
         FIG. 2  shows a cross sectional view of  FIG. 1 ; 
         FIGS. 3A and 3B  show an enlarged view of a portion A indicated in  FIG. 2  respectively; and 
         FIGS. 4A and 4B  show an enlarged view of a portion B indicated in  FIG. 2  respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     It will be appreciated by those of ordinary skill in the art that the present disclosure can be embodied in other specific forms without departing from the spirit or essential characters thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. 
     One embodiment of the present disclosure discloses a connection terminal  100  of a high-voltage cable as shown in  FIGS. 1 and 2 , which comprises a connector  70 , a cable  10  having a conductive core  30  and an insulating layer  20  surrounding the conductive core  30 . The connector  70  may have a connecting end  701  and a free end  702  connected therewith. As shown in  FIG. 1 , the connector  70  is coupled to the conductive core  30 , and a first plastic layer  40  and a second plastic layer  60  surround the cable  10  to seal the connector  70  and the insulating layer  20 . The first plastic layer  40  surrounds at least a part of the free end  702  of the connector  70  and at least a part of the insulating layer  20 . The second plastic layer  60  surrounds at least a part of the first plastic layer  40  and at least a part of the free end  702  of the connector  70 . 
     The conductive core  30  may be coupled to the connector  70 , and the connector  70  may be connected to a working device (not shown). Then the cable  10  can transmit current or voltage signal to the working device via the conductive core  30  and the connector  70 . 
     In one embodiment, the free end  702  may have a hollow chamber  703 . The conductive core  30  can be placed or inserted therein directly. During assembling, the conductive core  30  may be pressed fit into the hollow chamber  703 , so that there is a tight and reliable connection between the connector  70  and the cable  10 . 
     To ensure the connection terminal is waterproof and insulating, the first plastic layer  40  is formed to surround at least a part of the free end  702  of the connector  70  and at least a part of the insulating layer  20 , as shown in  FIG. 2 . The first plastic layer  40  may be injection molded onto the connector  70  and the insulating layer  20 . Then, the second plastic layer  60  may be formed to surround at least a part of the first plastic layer  40  and at least a part of the free end  702  of the connector  70 . As shown in  FIG. 2 , the entire connector  70  may be covered by the second plastic layer  60  with the connecting end  701  exposed to the outside. 
     The manufacturing method may be described as follows. In one embodiment, the second plastic layer  60  has an injection molding temperature higher than that of the first plastic layer  40 . That is to say, a first insulating material having a lower injection molding temperature is used to form the first plastic layer  40 , for instance, the first insulating material having a lower injection molding temperature of about 120° C. to about 160° C. Then a second insulating material having a higher injection molding temperature is used to form the second plastic layer  60 , for instance, the second insulating material having a higher injection molding temperature of about 160° C. to about 220° C. 
     To enhance the binding force between the plastic layer  40  and  60 , the connected connector  70  and cable  10 , mating features may be formed on the connector  70 , the first plastic layer  40  and/or the second plastic layer  60 . 
       FIGS. 3A and 3B  show an enlarged view of a portion A indicated in  FIG. 2  respectively. And  FIGS. 4A and 4B  show an enlarged view of a portion B indicated in  FIG. 2  respectively, showing the mating structures. 
     As shown in  FIG. 3A , the first plastic layer  40  is formed with at least a protrusion  401  (such as two shown in  FIG. 3A ), so that when the second plastic layer  60  is formed, such as by injection molding, onto the first plastic layer  40 , the melt second plastic material of the second plastic layer  60  is bound tightly onto the first plastic layer  40 , thus further enhancing the reliability of the connection terminal  100 . 
     According to another embodiment of the disclosure, the first plastic layer  40  may be further formed with at least a groove  401 ′ (such as one shown in  FIG. 3B ), so that when the second plastic layer  60  is formed, such as by injection molding, onto the first plastic layer  40 , the melt second plastic material of the second plastic layer  60  is bound tightly onto the first plastic layer  40 , thus further enhancing the reliability of the connection terminal  100 . 
     Alternatively, to enhance the binding force between the connector  70  and the second plastic layer  60 , an outer surface  705  of the free end  702  of the connector  70  is formed with at least a groove or at least a protrusion. In  FIG. 4A , three grooves  704  are formed on the outer surface  705 , so that when the second plastic layer  60  is formed, such as by injection molding, onto the free end  702 , the melt second plastic material of the second plastic layer  60  is bound tightly onto the connector  70 , thus further enhancing the reliability of the connection terminal  100 . According to another embodiment of the disclosure, three grooves  704 ′ are formed on the outer surface  705 , which may also enhance the reliability of the connection terminal  100 . 
     The thickness and length of the plastic layers  40  and  60  may be designed according to practical requirements, such as according to the current or voltage to be transmitted by the cable  10 . 
     In some embodiments of the disclosure, the first plastic layer  40  may be made of insulating materials, such as PVC (polyvinyl chloride) or TPU (thermoplastic polyurethane). The second plastic layer  60  may be made of insulating materials, such as PA (Polyamide) or PBT (Polybutylene terephthalate). 
     Although the present disclosure have been described in detail with reference to several embodiments, additional variations and modifications exist within the scope and spirit as described and defined in the following claims.