Patent Publication Number: US-9887477-B1

Title: Fused-wire cable connectors for a busbar

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to cable connectors and, more specifically, to fused-wire cable connectors for a busbar. 
     BACKGROUND 
     Vehicles and other systems utilize buses to distribute power to multiple pieces of equipment. Generally, a bus has a conductive busbar that is electrically coupled to a power source and includes a plurality of connection points. Typically, the connection points receive cables, which are coupled to corresponding equipment of the system, to facilitate distribution of power or a voltage signal from the source to the equipment of the system via the bus. 
     SUMMARY 
     The appended claims define this application. The present disclosure summarizes aspects of the embodiments and should not be used to limit the claims. Other implementations are contemplated in accordance with the techniques described herein, as will be apparent to one having ordinary skill in the art upon examination of the following drawings and detailed description, and these implementations are intended to be within the scope of this application. 
     Example embodiments are disclosed for fused-wire cable connectors for a busbar. An example disclosed cable includes wires, insulation around the wires, and a connector extending from the wires beyond the insulation. The example connector is formed from ends of the wires that are fused together. The example connector defines an aperture that is to receive a fastener to couple the connector to a busbar. 
     An example disclosed method to fabricate a cable connector includes forming a connector of a cable from ends of wires of the cable by inserting the ends into a mold, heating the ends, and fusing the ends together by pressing the heated ends into the mold. The example method includes forming an aperture in the connector that is to receive a fastener to couple the connector to a busbar. 
     An example disclosed electrical bus system includes a busbar including a port that defines a first aperture. The example system includes a cable including wires and a connector formed from ends of the wires that are fused together. The example connector defines a second aperture. The example system also includes a fastener to extend through the first aperture and the second aperture when the connector is received by the port to couple the connector of the cable to the port of the busbar. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the invention, reference may be made to embodiments shown in the following drawings. The components in the drawings are not necessarily to scale and related elements may be omitted, or in some instances proportions may have been exaggerated, so as to emphasize and clearly illustrate the novel features described herein. In addition, system components can be variously arranged, as known in the art. Further, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  illustrates a bus system in accordance with the teachings herein. 
         FIG. 2  illustrates an end of a cable of the bus system of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of a mold and an anvil that form a cable connector in accordance with the teachings herein. 
         FIG. 4  is a front view of a cable connector formed at the end of the cable of  FIG. 2 . 
         FIG. 5  is a perspective view of the cable connector of  FIG. 4 . 
         FIG. 6  illustrates a port of a busbar of the bus system of  FIG. 1  that is to receive the cable connector of  FIGS. 4-5 . 
         FIG. 7  illustrates the port of  FIG. 6  receiving the cable connector of  FIGS. 4-5 . 
         FIG. 8  illustrates the cable connector of  FIGS. 4-5  coupled to the port of  FIG. 6  via a fastener. 
         FIG. 9  is a perspective view of cable connectors that are received by respective ports of the busbar of the bus system of  FIG. 1 . 
         FIG. 10  is a top view of the cable connectors and the ports of  FIG. 9 . 
         FIG. 11  is a flowchart of a method to form the cable connector of  FIGS. 4-5 and 7-10  and/or the cable connector of  FIGS. 9-10  in accordance with the teachings herein. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     While the invention may be embodied in various forms, there are shown in the drawings, and will hereinafter be described, some exemplary and non-limiting embodiments, with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
     Oftentimes, buses are utilized to distribute power to multiple pieces of equipment within a system. For example, a vehicle may include a power distribution bus and/or a main electrical distribution bus that distributes power and/or a voltage signal to various electrical components of the vehicle. Buses typically have a conductive busbar that includes connection points and is electrically coupled to a power source (e.g., a battery). Each of the connection points may receive a cable that is coupled to a corresponding component of the system, thereby enabling the bus to distribute a voltage from the power source and to the system components. In some instances, the cable is coupled to the connection point by clamping wiring of the cable to the connection point. In other instances, a terminal is crimped on the wiring and is clamped to the connection point. Over time, the crimped terminal may loosen from the wiring and/or the connection point, potentially increasing electrical resistance between the cable and the busbar. 
     The example systems, apparatus, and methods disclosed herein facilitate a secure, low-resistance coupling between a cable and a busbar. An example cable disclosed herein includes conductive wires, insulation around the wires, and a connector formed from fused ends of the wires that extend beyond the insulation. The connector defines an aperture (e.g., a threaded aperture) that is to receive (e.g., threadably receive) fastener to enable the connector to securely couple the cable to a busbar (e.g., that distributes power to electrical components of a vehicle). In some examples, the connector has a trapezoidal (e.g., an isosceles trapezoidal) cross-section that enables a secure, torsional-resistant and/or low-resistance coupling between the connector and the busbar. Additionally or alternatively, a surface of the connector is plated with a highly conductive material (e.g., tin, silver, gold, etc.) to increase a conductivity of the connection between the cable and the busbar. 
     In some examples, the wire-fused connector is received by a port of the busbar such that the aperture of the connector aligns with another aperture of the port. A fastener extends through the apertures of the connector and the port to couple the connector of the cable to the port of the busbar. The port may include a protrusion that engages an end of the connector to enable the apertures to align. Additionally or alternatively, the port includes a base and opposing flanges protruding from the base. To electrically couple the cable to the busbar, the connector contacts the base and/or at least one of the flanges of the port. In some examples, the port has a trapezoidal cross-section that is less than the trapezoidal cross-section of the connector to enable the connector to press fit, wedge and/or otherwise be securely inserted into to the port. Further, at least one of the flanges may include ribs that scratch, scrape or cut into a surface of the connector as the connector is inserted into the port to remove or fracture oxidation that has formed on the surface of the connector. By removing the surface oxide from the connector, electrical resistivity is reduced between the connector and the port. 
     The fused-wire connector is formed by inserting the ends of the wires into a mold and heating the ends to a temperature at which the ends may fuse together. The ends of the wires may be heated by a localized heat source, solid state diffusion and/or friction produced by an ultrasonic horn. Further, the heated ends are pressed into the mold to fuse the ends together to form the connector. For example, an anvil applies a force to the ends of the wires to press the ends into the mold. In some examples, the mold has a trapezoidal cross-section to form a connector having a trapezoidal cross-section. Further, upon forming the connector by fusing the ends of the wires of the cable, the connector may be cooled and the aperture subsequently may be formed by drilling or punching the aperture into the connector. 
     Turning to the figures,  FIG. 1  depicts an example bus  102  of a vehicle  104  in accordance with the teachings herein. The vehicle  104  may be a standard gasoline powered vehicle, a hybrid vehicle, an electric vehicle, a fuel cell vehicle, and/or any other mobility implement type of vehicle. The vehicle  104  includes parts related to mobility, such as a power-train with an engine, a transmission, a suspension, a driveshaft, and/or wheels, etc. The vehicle  104  may be non-autonomous, semi-autonomous (e.g., some routine motive functions controlled by the vehicle  104 ), or autonomous (e.g., motive functions are controlled by the vehicle  104  without direct driver input). 
     The bus  102  may be a power distribution bus, a main electrical distribution bus and/or any other type of bus that distributes power and/or a voltage signal to one or more electrical components in the vehicle  104 . The bus  102  includes ports  106 ,  108  that receive cables  110 ,  112  to distribute power and/or a voltage signal to the components of the vehicle  104 . For example, the cable  110  (e.g., a first cable) is coupled to the bus  102  via the port  106  (e.g., a first port), and the cable  112  (e.g., a second cable) is coupled to the bus  102  via the port  108  (e.g., a second port). For example, each of the cables  110 ,  112  is coupled to a respective electrical component of the vehicle  104  to distribute power and/or a voltage signal, via the bus  102 , from a power source to that electrical component. In other examples, one of the cables  110 ,  112  may be coupled to the power source and the other of the cables  110 ,  112  may be coupled to another electrical component of the vehicle  104  to distribute a voltage to the other component of the vehicle  104 . 
       FIG. 2  depicts a portion of the cable  110  that is coupled to the bus  102  of  FIG. 1 . The cable  110  includes insulation  202  extending around wires  204  that is dielectric to cover and/or insulate the wires  204 . As illustrated in  FIG. 2 , ends  206  of the wires  204  extend beyond and/or protrude from the insulation  202 . For example, a portion of the insulation  202  may be stripped to enable the ends  206  of the wires  204  to extend beyond the insulation  202 . The wires  204  contain aluminum, copper and/or any other conductive material that may be melted to fuse together. Further, the insulation  202  contains a thermoplastic, a thermoset, and/or any other material that insulates the wires  204  from a surrounding environment. 
       FIG. 3  is a cross-section of an example mold  302  and an example anvil  304  that form a cable connector (e.g., a connector  400  of  FIGS. 4-5 and 7-10  and/or a connector  902  of  FIGS. 9-10 ) in accordance with the teachings herein. As illustrated in  FIG. 3 , the end  206  of the wires  204  of the cable  110  is inserted into the mold  302 . Further, the wires  204  are heated via a localized heat source, an ultrasonic horn that produces friction, solid state diffusion, and/or any other apparatus or method that is able to heat the ends  206  of the wires  204  to their melting point. Upon heating the wires  204  and positioning the ends  206  into the mold  302 , the anvil  304  applies a force to the wires  204  to press the exposed portion of the wires  204  into the mold  302  to fuse the ends  206  of the wires  204  into the cable connector. That is, the ends  206  of the wires  204  are heated and inserted into the mold  302 , and the anvil  304  applies a force to the ends  206  to form the ends  206  of the wires  204  into the cable connector. 
     In the illustrated example, the mold  302  has a trapezoidal cross-section to cause the mold  302  and the anvil  304  to fuse the ends  206  of the wires  204  together into a corresponding trapezoidal cross-section of the cable connector. More specifically, the cross-section of the mold  302  and the corresponding cross-section of the cable connector may be an isosceles trapezoid. In other examples, the mold  302  and the cable connector formed by the mold may have any other cross-section that enables the cable connector to electrically couple to the bus  102  in a secure and/or low-resistive manner. 
     Further, in some examples, the mold  302  may have a length that is greater than that of the ends  206  of the wires  204  such that a portion of the mold  302  is initially unfilled by the wires  204  of the cable  110 . When the force is applied to the wires  204 , the heated material of the wires  204  flows into the portion of the mold  302  that is initially unfilled by the wires  204 , thereby preventing the heated material of the wires  204  from overflowing from the mold  302  when the force is applied via the anvil  304 . 
       FIGS. 4 and 5  depict an example connector  400  of the cable  110  that is formed, for example, via the mold  302  and the anvil  304  of  FIG. 3 . More specifically,  FIG. 4  is a front view and  FIG. 5  is a perspective view of the connector  400  of the cable  110 . 
     As illustrated in  FIG. 4 , the connector  400  of the cable  110  has a trapezoidal (e.g., an isosceles trapezoidal) cross-section (e.g., a first trapezoidal cross-section) that enables the connector  400  to be securely received by and/or to form a low-resistance electrical coupling with the port  106  of the bus  102 . However, the connector  400  may have any other cross-section that enables the connector  400  to form a secure, low-resistive coupling to the bus  102 . Further, because the connector  400  is formed from the wires  204  of the cable  110 , the connector  400  contains the same material as the wires  204  such as aluminum and/or copper. 
       FIG. 5  further depicts the connector  400  of the cable  110  that is formed from the wires  204  and protrudes beyond the insulation  202 . The connector  400  includes a surface  502  (e.g., a first surface), an opposing surface  504  (e.g., a second surface), and opposing side surfaces  506 ,  508  (e.g., a first side surface and a second side surface, respectively) extending between the opposing surfaces  502 ,  504 . The surfaces  502 ,  504  define the bases and the side surface  506 ,  508  define legs of the trapezoidal cross-section of the connector  400 . In the illustrated, the surface  504  has a width  510  that defines the shorter of the bases of the trapezoidal cross-section. 
     Further, as illustrated in  FIG. 5 , the connector  400  defines an aperture  512  that extends between the surface  502  and the surface  504  of the connector  400 . The aperture  512  is to receive a fastener (e.g., a fastener  802  of  FIG. 8 ) that couples the connector  400  to the port  106  to electrically couple the cable  110  to the bus  102 . In some examples, the aperture  512  includes threads  514  that receive a threaded fastener to enable the threaded fastener to couple to the connector  400 . In other examples, the aperture  512  is not threaded. 
       FIG. 6  illustrates the port  106  of a busbar  602  of the bus  102  that is to receive the connector  400  of the cable  110  in accordance with the teachings herein. The busbar  602 , including the port  106 , contains aluminum, copper and/or any other conductive material to enable power and/or a voltage signal to be distributed from a power source (e.g., a battery) and through the busbar  602  to an electrical component of the vehicle  104 . 
     The port  106  includes a base  604 , a flange  606  (e.g., a first flange), and another flange  608  (e.g., a second flange). In the illustrated example, the flange  606  protrudes from the base  604  in a first direction and the flange  608  protrudes from the base  604  in an opposing second direction to define a trapezoidal (e.g., an isosceles trapezoidal) cross-section (e.g., a second trapezoidal cross-section) of the base  604 . For example, the first trapezoidal cross-section of the port  106  is less than the second trapezoidal cross-section of the connector  400  such that a width  610  of the base  604  of the port  106  is less than the width  510  of the surface  502  of the connector  400 . As a result, the connector  400  may be press fit and/or wedged into the port  106  to further securely couple the connector  400  of the cable  110  to the port  106 . 
     As illustrated in  FIG. 6 , the base  604  defines an aperture  612  of the port  106  that is to receive the fastener (e.g., the fastener  802  of  FIG. 8 ) to couple the connector  400  to the port  106 . In the illustrated example, the aperture  612  includes threads  614  that receive a threaded fastener to couple to the threaded fastener to the port  106  of the busbar  602 . In other examples, the aperture  612  of the port  106  is not threaded. The example port  106  also includes a protrusion  616  extending from the base  604  of the port  106 . The protrusion  616  is to engage a portion of the connector  400  to enable the aperture  612  of the port  106  to align with the aperture  512  of the connector  400  to enable the apertures  512 ,  612  to receive the fastener to couple the connector  400  to the port  106 . 
     Further, in the illustrated example, the flange  606  and/or the flange  608  includes ribs  618  that scratch, scrape, and/or cut into the side surface  506  of the connector  400  as the connector  400  is inserted into and/or received by the port  106  to remove or fracture oxidation of the side surface  506  of the connector  400 . For example, surface oxides may form along the side surface  506 , the surface  502 , the surface  504 , and/or the side surface  508  of the connector  400  as a result of the wires  204  being fused together to form the connector  400 . In some instances, the surface oxides may increase a resistivity between connector  400  and the port  106 . Thus, the ribs  618  potentially further reduce the contact resistance of the coupling between the connector  400  and the port  106  by removing oxidation from the side surface  506  of the connector  400 . Additionally or alternatively, the flange  608  and/or the base  604  of the port  106  includes the ribs  618  to remove oxidation from the side surface  508  and/or the surface  504 , respectively, to remove oxidation from the connector  400 . Further, the ribs  618  may extend into the connector  400  to prevent creep or joint relaxation between the connector  400  and the port  106  to further secure the connector  400  in the port  106 . 
       FIG. 7  depicts the connector  400  of the cable  110  and the port  106  of the busbar  602  when the connector  400  is inserted into and/or received by the port  106 . As illustrated in  FIG. 7 , the protrusion  616  of the port  106  engages an end  702  of the connector  400  to limit movement of the connector  400  relative the port  106 . For example, the protrusion  616  deters the connector  400  from being inserted into the port  106  beyond a predetermined point to align the aperture  512  of the connector  400  with the aperture  612  of the port  106 . Thus, by inducing alignment of the apertures  512 ,  612 , the protrusion  616  facilitates a fastener to extend through the apertures  512 ,  612  to couple the connector  400  to the port  106 . 
     Further, the connector  400  and the port  106  of the illustrated example have respective trapezoidal cross-sections so that at least one surface of the connector  400  contacts at least one surface of the port  106  when the connector  400  is received by the port  106 . For example, the connector  400  and the port  106  have trapezoidal cross-sections to enable the surface  504  and the base  604 , the side surface  506  and the flange  606  and/or the side surface  508  and the flange  608  to contact each other when the connector  400  is inserted into the port  106 . Thus, the trapezoidal cross-sections of the connector  400  and the port  106  facilitate an electrical coupling between the connector  400  of the cable  110  and the port  106  of the busbar  602 . 
     In the illustrated example, the connector  400  is wedged and/or press fit into the port  106  to enable the connector  400  to be securely coupled to the port  106 . For example, the connector  400  is nominally larger than the port  106  so that the surface  504  contacts the base  604 , the side surface  506  contacts the flange  606 , and the side surface  508  contacts the flange  608  when the connector  400  is received by the port  106 . Because multiple surfaces of the connector  400  contact multiple respective surfaces of the port  106 , the conductivity of the coupling between the connector  400  and the port  106  is increased. Additionally or alternatively, one or more surfaces of the connector  400  and/or the port  106  are plated with highly conductive material (e.g., tin, silver, gold) to further increase the conductivity of the coupling between the connector  400  and the port  106 . For example, at least one of the surface  504  and the side surfaces  506 ,  508  of the connector  400  and/or at least one of the base  604  and the flange  606 ,  608  is plated to reduce the contact resistance of the coupling between the connector  400  and the port  106 . 
       FIG. 8  depicts the connector  400  of the cable  110  coupled to the port  106  of the busbar  602  via a fastener  802  in accordance with the teachings herein. The fastener  802  of the illustrated example includes a bolt  804 , a washer  806 , and a nut. For example, the bolt  804  extends through the washer  806 , the aperture  512  of the connector  400 , and the aperture  612  of the port  106  and is received (e.g., threadably received) by the nut to couple the connector  400  of the cable  110  to the port  106 . In other examples, the bolt  804  couples the connector  400  to the port  106  without a bolt by being threadably received by the threads  614  of the aperture  612  of the port  106 . Further, in some examples, the washer  806  is a Belleville washer or a spring washer that further secures the connector  400  to the port  106  by maintaining a clamp load between the bolt  804  and the nut and/or by preventing creep or joint relaxation between the connector  400  and the port  106 . 
       FIG. 9  is a perspective view of the cables  110 ,  112  coupled to the busbar  602  via the respective ports  106 ,  108 . As illustrated in  FIG. 9 , the connector  400  of the cable  110  is coupled to the port  106  of the busbar  602  via the fastener  802 , and a connector  902  of the cable  112  is coupled to the port  108  of the busbar  602  via a fastener  904 . The connector  902  is substantially similar or identical to the connector  400  and the fastener  904  is substantially similar or identical to the fastener  802 . Because the connector  400  is described in detail in connection with  FIGS. 4-5 and 7-8  and the fastener  802  is described in detail in connection with  FIG. 8 , some characteristics of the connector  902  and the fastener  904  of  FIG. 9  are not described in further detail below. 
     Returning to  FIG. 1 , the ports  106 ,  108  and the respective cables  110 ,  112  enable the busbar  602  of the bus  102  to distribute power and/or a voltage signal provided by a power source to multiple components within the vehicle  104 . For example, the busbar  602  may distribute, via the port  106  and the connector  400 , a voltage to a component of the vehicle  104  that is coupled to the cable  110 . Further, the busbar  602  may distribute, via the port  108  and the connector  902 , the same voltage to another component of vehicle  104  that is coupled to the cable  112 . 
       FIG. 10  is a top view of the cables  110 ,  112  coupled to the busbar  602  via the respective ports  106 ,  108 . In the illustrated example, the end  702  of the connector  400  is spaced apart from a center of the aperture  512  by a distance  1002 , and the protrusion  616  is spaced apart from a center of the aperture  612  of the port  106  by the distance  1002 . Further, a distance  1004  separates a center of an aperture of the connector  902  and an end  1006  of the connector  902 , and the  1004  distance separates a center of an aperture of the port  108  and a protrusion  1008  of the port  108 . 
     As illustrated in  FIG. 10 , the distance  1004  is different than (e.g., greater than) the distance  1002  to facilitate the cables  110 ,  112  to be coupled to the corresponding ports  106 ,  108  for which they are designated. That is, the distance  1002  enables the cable  110  to be inserted into the designated port  106 , and the distance  1004  enables the cable  112  to be inserted into the designated port  108 . For example, the apertures  512 ,  612  of the connector  400  and the port  106  align when the connector  400  is inserted into the port  106 , because the end  702  of the connector  400  and the protrusion  616  of the port  106  are spaced apart from the corresponding apertures  512 ,  612  by the same distance  1004 . If the connector  400  with the corresponding distance  1002  was inserted into the port  108  with the corresponding distance  1004 , the aperture  512  of the connector  400  would not align with the aperture of the port  108 . Similarly, the apertures of the connector  902  and the port  108  align when the connector  902  is inserted into the port  108 , because the end  1006  of the connector  902  and the protrusion  1008  of the port  108  are spaced apart from the corresponding apertures by the same distance  1004 . The aperture of the connector  902  would not align with the aperture  612  of the port  106  if the connector  902  was inserted into the port  106 . 
       FIG. 11  is a flowchart of an example method  1100  to form a wire-fused cable connector in accordance with the teachings herein. In some examples, the flowchart of  FIG. 11  is representative of machine readable instructions that are stored in memory and include one or more programs executed to form a wire-fused cable connector. While the example program(s) is/are described with reference to the flowchart illustrated in  FIG. 11 , many other methods for forming a wire-fused cable connector may alternatively be used. For example, the order of execution of the blocks may be rearranged, changed, eliminated, and/or combined to perform the method  1100 . 
     The method  1100  is disclosed in connection with the components of  FIGS. 3-5 and 7-10 . Thus, some functions of those components will not be described in detail below. Further, while the method  1100  is disclosed below in connection with fabrication of the connector  400  of  FIGS. 4-5 and 7-10 , the method  1100  may be utilized to fabricate the connector  902  and/or any other wire-fused cable connector. 
     Initially, at block  1102 , a cable end of the cable  110  is stripped of the insulation  202 . At block  1104 , the cable end (e.g., the ends  206  of the wires  204 ) is heated. For example, the cable end is heated via a localized heat source, solid state diffusion and/or friction produced by an ultrasonic horn. At block  1106 , the method  1100  includes determining whether the cable end of the cable  110  has been heated to a temperature at which the ends  206  of the wires  204  are able to be fused together. If the wires  204  are not able to be fused together, the method  1100  returns to block  1104 . Otherwise, if the wires  204  are able to be fused together, the method  1100  continues to block  1108  at which the cable end is inserted into the mold  302 . At block  1110 , the cable end is pressed into the mold  302  via the anvil  304  to form a cable connector (e.g., the connector  400 ). For example, a cable end is pressed into the mold having a trapezoidal cross-section to enable the cable connector to have a trapezoidal cross-section. 
     At block  1112 , the method  1100  includes facilitating cooling of the cable connector. At block  1114 , the method  1100  includes determining whether the cable collector has solidified and/or hardened. If the cable collector has not solidified, the method  1100  returns to block  1112 . Otherwise, if the cable collector has solidified, the method  1100  proceeds to block  1116  at which the aperture  512  is formed in the cable connector. For example, the aperture  512  is formed via punching or drilling the aperture  512  into the cable connector. In some examples, the aperture  512  is further formed by the threading the aperture  512 . At block  1118 , a surface (e.g., the surface  502 , the surface  504 , the side surface  506 , the side surface  508 ) of the cable connector is plated to increase conductivity of the cable connector. For example, the cable connector contains aluminum and/or copper and is plated with tin, silver, and/or gold. 
     In this application, the use of the disjunctive is intended to include the conjunctive. The use of definite or indefinite articles is not intended to indicate cardinality. In particular, a reference to “the” object or “a” and “an” object is intended to denote also one of a possible plurality of such objects. Further, the conjunction “or” may be used to convey features that are simultaneously present instead of mutually exclusive alternatives. In other words, the conjunction “or” should be understood to include “and/or”. The terms “includes,” “including,” and “include” are inclusive and have the same scope as “comprises,” “comprising,” and “comprise” respectively. 
     The above-described embodiments, and particularly any “preferred” embodiments, are possible examples of implementations and merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment(s) without substantially departing from the spirit and principles of the techniques described herein. All modifications are intended to be included herein within the scope of this disclosure and protected by the following claims.