Patent Publication Number: US-2023164965-A1

Title: Wire harness

Description:
BACKGROUND 
     The present disclosure relates to a wire harness. 
     Conventionally, wire harnesses used for vehicles such as hybrid cars and electric automobiles are routed under the floor of vehicles or the like in some cases. Further, there are cases where such a wire harness includes a plurality of wires and a metal outer cover member that is configured to individually accommodate these wires and serves as a plurality of electromagnetic shielding members, for example (e.g., see JP 2005-44607A). With such a wire harness, it is possible to obtain a high electromagnetic shielding effect due to the metal outer cover member. 
     SUMMARY 
     However, the above-described wire harness is problematic in that the wire harness has a large overall cross-sectional area in a direction that is orthogonal to the direction in which the wire harness extends because the wires are accommodated with gaps interposed between the outer cover member and the wires, for example. Also, even when a braided member obtained by braiding metal wires is adopted as an electromagnetic shielding member and fitted around the wires, instead of the metal outer cover member, gaps are present between metal wires constituting the braided member. Thus, such a configuration is problematic in that the thickness thereof increases when attempts are made to ensure a high electromagnetic shielding effect, resulting an increase in the overall cross-sectional area in the direction orthogonal to the direction in which the wire harness extends. 
     An exemplary aspect of the disclosure provides a wire harness that can achieve a size reduction and ensure a high electromagnetic shielding effect. 
     A wire harness according to this disclosure includes a shielded wire having a core wire, an insulating cover covering an outer surface of the core wire, and an electromagnetic shield covering the insulating cover, in which the electromagnetic shield is a metal layer that is seamlessly formed in intimate contact with an outer surface of the insulating cover. 
     According to the wire harness of this disclosure, it is possible to achieve a size reduction and ensure a high electromagnetic shielding effect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of a vehicle in one embodiment. 
         FIG.  2    is a cross-sectional view of a wire harness in one embodiment. 
         FIG.  3    is an enlarged schematic view of a wire harness in one embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Description of Embodiments of the Present Disclosure 
     First, embodiments of this disclosure will be listed and described below. 
     A wire harness according to this disclosure is 
     (1) a wire harness including a shielded wire having a core wire, an insulating cover covering an outer surface of the core wire, and an electromagnetic shielding member covering the insulating cover, in which the electromagnetic shielding member is a metal layer that is seamlessly formed in intimate contact with an outer surface of the insulating cover. 
     According to this configuration, because the electromagnetic shielding member is a metal layer that is seamlessly formed in intimate contact with the outer surface of the insulating cover, it is possible to ensure a higher electromagnetic shielding effect while reducing the cross-sectional area in a direction orthogonal to a direction in which the electromagnetic shielding member extends, compared to a case where the electromagnetic shielding member is a metal outer cover member, a metal braided member, or the like, for example. 
     (2) It is preferable that the wire harness further includes a metal member connected to the shielded wire, in which the metal layer is formed over the metal member. 
     According to this configuration, because the metal layer is formed over the metal member connected to the shielded wire, it is possible to connect the metal layer to the metal member without using an additional connecting component such as a crimping band, and to establish an electromagnetic shield structure, for example. 
     (3) It is preferable that the insulating cover is made of enamel. 
     According to this configuration, because the insulating cover is made of enamel, higher heat resistance can be achieved, compared to a case where another ordinary insulating cover is used. Therefore, a manufacturing method with which a metal layer is formed by spraying heated metal powder onto the outer surface of the insulating cover can be easily adopted. 
     (4) It is preferable that the core wire is constituted by a bus bar. 
     According to this configuration, because the core wire is constituted by a bus bar, the enamel does not permeate through the core wire when forming the insulating cover made of enamel. That is, if the core wire is constituted by a twisted wire, the enamel may permeate through the core wire when forming the insulating cover made of enamel. However, this situation can be avoided. 
     DETAILS OF EMBODIMENTS OF THE PRESENT DISCLOSURE 
     Specific examples of the wire harness of this disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is indicated by the claims, and changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein. 
     As shown in  FIG.  1   , a wire harness  10  electrically connects two electrical apparatuses (devices), or three or more electrical apparatuses (devices). The wire harness  10  electrically connects a battery  11  disposed in a rear portion of a vehicle V and an electrical component  12  disposed in a front portion of the vehicle V, for example. Note that high-voltage batteries that can supply a voltage of 100 volts or more, or low-voltage batteries that can supply a voltage of 1.2 volt, 24 volt, or the like can be adopted as the battery  11 . Further, if a high-voltage battery  11  is adopted, an inverter connected to a motor for driving wheels or the like can be adopted as the electrical component  12 , for example. Also, if a low-voltage battery  11  is adopted, a distribution board box connected to small motors or the like can be adopted as the electrical component  12 , for example. In this embodiment, a case where a high-voltage battery  11  is adopted and a wire harness  10  that handles large currents is adopted will be described. The wire harness  10  is routed such that the central portion thereof extends under the floor of the vehicle V or the like, and two ends thereof extend upward from below the floor and are connected to the battery  11  and the electrical component  12  that are provided on the floor. 
     The wire harness  10  includes a central wire harness  21  constituting wiring located at the central portion under the floor, end wire harnesses  22  each constituting wiring at two end portions, and connection members  23  serving as metal members for connection the central wire harness  21  and the end wire harnesses  22 . 
     As shown in  FIG.  2   , the central wire harness  21  includes a core wire  31  and an insulating cover  32  covering an outer surface of the core wire  31 , The core wire  31  is constituted by a bar-shaped bus bar made of a metal such as aluminum or copper. The shape of a cross-section of the core wire  31  in this embodiment that is orthogonal to the direction in which the core wire  31  extends is a rectangle, and the core wire  31  is arranged such that the length in the width direction of the vehicle V is larger than the length in the up-dawn direction thereof. The insulating cover  32  is made of enamel. 
     Also, the central wire harness  21  is a shielded wire having a metal layer  33  serving as an electromagnetic shielding member (electromagnetic shield) covering the insulating cover  32 , The metal layer  33  is seamlessly formed in intimate contact with the outer surface of the insulating cover  32 . Specifically, the metal layer  33  is provided so as to cover the entire outer peripheral surface of the insulating cover  32 , but does not have a seam as if a metal foil is bonded. Also, the metal layer  33  has no seams such as that in a braided member obtained by braiding metal wires, and has no gaps resulting from the formation of a seam. This metal layer  33  is formed by spraying heated metal powder onto the outer surface of the insulating cover  32 . 
     Also, as shown in  FIG.  3   , the metal layer  33  is formed over the connection member  23 . That is, the metal layer  33  is formed as a single body from the outer surface of the insulating cover  32  to the outer surface of the connection member  23  in a state where a wire  34  constituted by a core wire  31  and the insulating cover  32  is connected to the connection member  23 . 
     Next, a method for manufacturing the wire harness  10  configured as above and the effects thereof will be described. 
     The method for manufacturing the wire harness  10  includes a connecting step of connecting the wire  34  constituted by the core wire  31  and the insulating cover  32  in the central wire harness  21  to the connection member  23 , and a forming step of forming the metal layer  33  by spraying heated metal powder  35  onto the outer surface of the insulating cover  32  after the connecting step. 
     Specifically, as shown in  FIG.  3   , in the forming step, the metal layer  33 , which extends from the outer surface of the insulating cover  32  to the outer surface of the connection member  23  and which is in intimate contact with these outer surfaces without a seam, is formed by spraying, from a nozzle  36 , the heated metal powder  35  onto the outer surface of the insulating cover  32  and the outer surface of the connection member  23 . This results in a state which the outer side of the wire  34  that includes the core wire  31  is surrounded by the metal layer  33 , and the metal layer  33  is electrically connected to the connection member  23 , which is a metal member. Thus, emission of electromagnetic noise from the core wire  31  to the outside is suppressed. 
     Next, the effects of the above embodiment will be described below. 
     (1) Because the electromagnetic shielding member is the metal layer  33  that is seamlessly formed in intimate contact with the outer surface of the insulating cover  32 , it is possible to ensure a higher electromagnetic shielding effect while reducing the cross-sectional area in a direction orthogonal to a direction in which the electromagnetic shielding member extends, compared to a case where the electromagnetic shielding member is a metal outer cover member, a metal braided member, or the like, for example. 
     (2) Because the metal layer  33  is formed over the connection member  23  connected to the central wire harness  21 , it is possible to connect the metal layer  33  to the connection member  23 , which is a metal member, without using an additional connecting component such as a crimping band, and to establish an electromagnetic shield structure, for example. That is, when a braided member is adopted as an electromagnetic shielding member, for example, the braided member needs to be disposed outside the metal member and connected thereto by fastening them together using a crimping band or the like. However, this need is eliminated. 
     (3) Because the insulating cover  32  is made of enamel, higher heat resistance can be achieved, compared to a case where another ordinary insulating cover is used. Therefore, a manufacturing method with which the metal layer  33  is formed by spraying the heated metal powder  35  onto the outer surface of the insulating cover  32  can be easily adopted. In other words, because the insulating cover  32  is made of highly heat resistant enamel in order to form the metal layer  33  by spraying the heated metal powder  35  onto the outer surface of the insulating cover  32 , the metal layer  33  can be easily manufactured, in addition to having the above-described effects. 
     (4) Because the core wire  31  is constituted by a bus bar, the enamel does not permeate through the core wire when forming the insulating cover  32  made of enamel. That is, if the core wire  31  is constituted by a twisted wire, the enamel may permeate through the core wire when forming the insulating cover  32  made of enamel. However, this situation can be avoided. 
     (5) Because the method for manufacturing the wire harness  10  includes the forming step of forming the metal layer  33  by spraying the heated metal powder  35  onto the outer surface of the insulating cover  32 , the wire harness  10  can be more easily manufactured, compared to a case where an electromagnetic shielding member is separately manufactured and attached to a wire, for example. 
     This embodiment can be modified and implemented as follows. This embodiment and the following modifications may be combined to the extent that they do not contradict each other technically
         Although the metal layer  33  is formed over the connection member  23  connected to the central wire harness  21  in the embodiment, the present disclosure is not limited to this. A configuration may be adopted in which the metal layer  33  is not formed over the connection member  23  and is connected to a connection member with another configuration, for example.   Although the insulating cover  32  is made of enamel in the embodiment, the present disclosure is not limited to this, and the insulating cover  32  may be an insulating cover made of another material.   Although the core wire  31  is constituted by a bus bar in the embodiment, the present disclosure is not limited to this, and the core wire  31  may be another type of core wire such as a core wire constituted by a twisted wire, for example.   Although not particularly mentioned in the above embodiment, a pair of the wire harnesses  10  may be arranged side-by-side in one vehicle V, or three or more wire harnesses  10  may be arranged side-by-side, for example.   Although not particularly mentioned in the above embodiment, the central wire harness  21  may be fixed to the vehicle V in a state in which the central wire harness  21  is accommodated in and held by a resin outer cover member that covers and holds the metal layer  33 , for example.   Although the wire harness  10  can handle large currents in the embodiment when a high-voltage battery  11  is adopted, the present disclosure is not limited to this and the wire harness  10  may be used as a wire harness to be used when a low-voltage battery  11  is adopted.       

     The technical ideas that can be grasped based on the embodiment and other examples will be described below together with the effects thereof. 
     (A) A method for manufacturing a wire harness provided with a shielded wire having a core wire, an insulating cover covering an outer surface of the core wire, and an electromagnetic shielding member covering the insulating cover, the electromagnetic shielding member being a metal layer that is seamlessly formed in intimate contact with an outer surface of the insulating cover, the method including a forming step of forming the metal layer by spraying heated metal powder onto the outer surface of the insulating cover. 
     According to this method, because the electromagnetic shielding member is a metal layer that is seamlessly formed in intimate contact with the outer surface of the insulating cover, it is possible to ensure a higher electromagnetic shielding effect while reducing the cross-sectional area in a direction orthogonal to a direction in which the electromagnetic shielding member extends, compared to a case where the electromagnetic shielding member is a metal outer cover member, a metal braided member, or the like, for example. Also, because the manufacturing method includes the forming step of forming the metal layer by spraying the heated metal powder onto the outer surface of the insulating cover, the wire harness can be more easily manufactured, compared to a case where an electromagnetic shielding member is separately manufactured and attached to a wire, for example. 
     The wire harness  10  may have a flat shape having a smaller dimension in the thickness direction thereof than the dimension in the width direction thereof, for example. As in the example shown in  FIG.  2   , the core wire  31  of the wire harness  10  may be a bus bar having a flat shape with a smaller dimension in the thickness direction thereof than the dimension in the width direction thereof, for example. The core wire  31  has a flat upper surface, a flat lower surface, and two opposing side surfaces, and a cross-section extending in the direction that is orthogonal to the direction in which the core wire  31  extends may be a rectangle. The outer surface of the core wire  31  may be provided with an insulating coating film  32  that has a uniform thickness and is in intimate contact with the core wire  31  so as to cover the entire outer surface thereof. The insulating coating film  32  may be enamel that adheres to the surface of the core wire  31  without permeating through the core wire  31 . The outer surface of the insulating coating film  32  may be provided with the metal layer  33  that has a uniform thickness and is in intimate contact with the insulating coating film  32  so as to cover the entire outer surface thereof. The metal layer  33  may be an electromagnetic shielding member of the wire harness  10 . The metal layer  33  (electromagnetic shielding member) may be provided so as to have the same shape as the shape of the outer surface of the core wire  31 , and the shape of the metal layer  33  in the example shown in  FIG.  2    is a rectangular cylinder having a fixed shape over the entire length of the central wire harness  21 . 
     The metal layer  33  may be formed in a state in which the wire  34  in which the insulating coating film  32  is adhered to the core wire  31  and the connection member  23  are connected to each other. The metal layer  33  may also be integrally formed in intimate contact with the outer surface of the insulating coating film  32  and the outer surface of the connection member  23 . As shown in  FIG.  3   , for example, a level difference or a gap extending in a radial direction may form between the outer surface of an end portion of the connection member  23  and the outer surface of the wire  34 . However, because the metal layer  33  is formed by spraying, from the nozzle  36 , the heated metal powder  35  onto the outer surface of the insulating cover  32  and the outer surface of the connection member  23 , the metal layer  33  may be seamlessly formed to have a substantially constant thickness over the connection portion having such a level difference. 
     The metal layer  33  shown in the illustrated example may be referred to as a seamless and slitless metal layer that continuously extends over the entire length of the metal layer  33  and over the entire periphery of the metal layer  33 . 
     As shown in the example in  FIG.  2   , the central wire harness  21  may be an insulating resin enamel bus bar such as a polyurethane enamel copper bus bar, for example.