Patent Publication Number: US-2010122831-A1

Title: Shield conductor

Description:
TECHNICAL FIELD 
     The present invention relates to a shield conductor. 
     BACKGROUND ART 
     Conventionally, the shield conductor disclosed in Patent Literature 1 has been well-known. This shield conductor comprises multiple wires, a braided wire enwrapping the wires, and a corrugated tube enwrapping the wires and the braided wire. The above-mentioned shield conductor is mounted in an electric vehicle and electrically connects between equipments such as an inverter and a motor. 
     [Patent literature 1]: Japanese Unexamined Patent Publication No. 2004-172476 
     DISCLOSURE OF THE INVENTION 
     In the shield conductor according to the above configuration, heat generated from the wires at the time of electricity application is transmitted sequentially from the wire, to the braided wire, and to the corrugated tube, and then is released from the corrugated tube to the outside of the shield conductor. However, according to the above configuration, an air layer exists between the wire and the braided wire, and between the braided wire and the corrugated tube. This air layer has a relatively low heat conductivity, therefore heat generated from the wires remains inside of the corrugated tube, and might cause a temperature rise of the wires. 
     In a case where the upper limit of the temperature rise value of the wires has been decided, the heating value at the time of electricity application may be lowered by enlarging the diameter of the wire. However, this method causes the enlargement of the entire shield conductor, and cannot therefore be employed. 
     This invention has been completed based on the above circumstances, and its purpose is to provide a shield conductor having improved heat dissipation property. 
     The present invention relates to a shield conductor comprising: a wire, a shielding layer for enwrapping the outer circumference of the wire, and a sleeve pipe for housing the wire and the shielding layer, wherein the outer circumference of the wire tightly adheres to the shielding layer, while the shielding layer tightly adheres to the inner circumference of the sleeve pipe. 
     With the configuration of the present invention, heat generated from the wire when electrical current is fed to the wire is transmitted from the wire to the shielding layer, and to the sleeve pipe, and then is released from the sleeve pipe to the outside of the shield conductor. With the configuration of the present invention, the outer circumference of the wire and the shielding layer tightly adhere each other, and moreover, the shielding layer and the inner circumference of the sleeve pipe tightly adhere each other. Accordingly, the heat conductivity from the wire to the sleeve pipe can be improved, thereby improving the heat dissipation property of the shield conductor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a shield conductor according to Embodiment 1; 
         FIG. 2  is a perspective view of a plate member; 
         FIG. 3  is an elevation view of the plate member; 
         FIG. 4  is a perspective view of the manufacturing process of the shield conductor; 
         FIG. 5  is a perspective view of the manufacturing process of the shield conductor; 
         FIG. 6  is a cross-sectional elevation view of the manufacturing process of the shield conductor; 
         FIG. 7  is a cross-sectional elevation view of the shield conductor; 
         FIG. 8A  is a cross-sectional view showing a state before a pin is inserted into an insertion hole; 
         FIG. 8B  is a cross-sectional view showing a state of the pin on the way to be inserted into the insertion hole; 
         FIG. 8C  is a cross-sectional view showing a state after the pin has been inserted into the insertion hole; 
         FIG. 9  is a perspective view showing a shield conductor according to Embodiment 2; 
         FIG. 10  is a cross-sectional elevation view of the shield conductor; 
         FIG. 11  is a cross-sectional elevation view showing a shield conductor according to Embodiment 3; 
         FIG. 12  is a cross-sectional elevation view showing a shield conductor according to Embodiment 4. 
     
    
    
     DESCRIPTION OF SYMBOLS 
     
         
           10  . . . shield conductor 
           11  . . . sleeve pipe 
           12  . . . braided wire (shielding layer) 
           13  . . . wire 
           16  . . . housing member 
           17  . . . plate member 
           18  . . . groove 
           22  . . . pin (pressing member) 
           26  . . . first plate member 
           27  . . . second plate member 
           28  . . . first groove 
           29  . . . second groove 
       
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Embodiment 1 
     In reference to  FIGS. 1 to 8 , Embodiment 1 of the present invention is described. As shown in  FIG. 1 , the shield conductor  10  according to the present embodiment is constituted by housing three wires  13  enwrapped by a braided wire  12  (corresponding to a shielding layer) in a sleeve pipe  11 . The shield conductor  10  is mounted in, for example, a vehicle (not shown) such as an electric vehicle and a hybrid vehicle, and electrically connects between equipments such as an inverter device (not shown) and a motor (not shown). The shield conductor  10  is fitted into the vehicle by a holding member (not shown) such as, for example, a clamp. 
     As shown in  FIG. 7 , the wire  13  is constituted by enwrapping the outer circumference of a core wire  14  made of metal (for example, such as aluminum alloy and copper alloy) with an insulating coating  15  made of synthetic resin (for example, such as polypropylene and polyethylene). The wire  13  according to the present embodiment is a non-shielded type. Regarding the cross-sectional shape of the wire  13 , the cross-section of both the core wire  14  and the insulating coating  15  are circular as shown in  FIG. 7 . Though not shown in details, the core wire  14  is composed of a twisted wire spirally twisting a plurality of thin wires or a rod-shaped single core wire. 
     As shown in  FIG. 1 , the braided wire  12  forms a tubular shape as a whole. This braided wire  12  is constituted by weaving a metal thin wire into meshes. Three wires  13  are collectively enwrapped by the braided wire  12 . The braided wire  12  is capable of stretching in the radial direction as well as the length direction due to the flexibility of the metal thin wire. 
     As shown in  FIG. 1 , provided in the sleeve pipe  11  are the first housing members  16  extending in the axial direction of the wire  13  (in a direction from the left front side to the right back side in  FIG. 1 ). Each housing member  16  is arranged in a row in a direction perpendicular to the extending direction of the wire  13  (in a direction from the right front side to the left back side in  FIG. 1 ) at intervals. Three wires  13  enwrapped by the braided wire  12  are separately housed in each housing member  16  (see  FIG. 7 ). This allows each wire  13  to be housed in the sleeve pipe  11  in a row in a direction perpendicular to the axial direction of the wire  13  at intervals. 
     As shown in  FIGS. 2 to 7 , the sleeve pipe  11  is formed by folding a plate member  17  made of synthetic resin. As a synthetic resin, for example, materials relatively having rigidity, such as polyethylene, polypropylene, PET, PBT, and nylon may be used. The plate member  17  is formed by a known method (for example, extrusion). As shown in  FIG. 2 , formed in the plate member  17  in a row in a direction from the right front side to the left back side are six grooves  18 . Each groove  18  is formed in a manner so as to extend from the left front side to the right back side in  FIG. 2 . As shown in  FIG. 3 , each groove  18  is formed in a manner so as to be recessed in some degree upwardly in  FIG. 3 , and its cross-sectional shape is semicircular. 
     In the plate member  17 , a folding member  19  for folding the plate member  17  is formed in the near-center in the right and left direction in  FIG. 3  in a manner so as to be recessed upwardly in  FIG. 3 . This folding member  19  is formed in a manner so as to extend along the extending direction of the groove  18  (in  FIG. 2 , from the left front side to the right back side). 
     As shown in  FIG. 7 , each groove  18  is formed in a position opposing each other when the plate member  17  is folded at the folding member  19 . Between the grooves  18  opposing each other, a spacing having a circular cross-sectional shape is formed. The wire  13  and the braided wire  12  are housed inside of this spacing, and thus the above-mentioned housing member  16  is constituted. The radius of the inner circumferential surface of the groove  18  is designed so as to be slightly smaller than the one obtained by adding the thickness of the braided wire  12  to the radius of the outer circumferential surface of the insulating coating of the wire  13 . 
     In the sleeve pipe  11 , an opposing wall  20  opposing each other is formed in both the right and left side of each housing member  16  in  FIG. 7 . Among the opposing walls  20 , first opposing walls  20 A provided in the places closest to the right and left end of the sleeve pipe  11  in  FIG. 7  abut each other from above and below. In addition, among the opposing walls  20 , second opposing walls  20 B provided near the center in the right and left direction of the sleeve pipe  11  in  FIG. 7  oppose each other with a spacing therebetween, in a state of the braided wire  12  held between the opposing walls  20 . This spacing is designed so as to be slightly smaller than twice of the thickness of the braided wire  12 . 
     As shown in  FIG. 2 , multiple insertion holes  21  are formed in the opposing wall  20  along the extending direction of the housing member  16  in a row at intervals, and penetrate through the opposing wall  20 . As shown in  FIG. 7 , the insertion hole  21  is formed in a position such that, when the plate member  17  is folded at the folding member  19 , the insertion hole  21  formed in the opposing wall  20  positioned upper side and the insertion hole formed in the opposing wall  20  positioned in the lower side correspond each other. This allows each insertion hole  21  to communicate vertically in  FIG. 7 , when the plate member  17  is folded at the folding member  19 . Inserted vertically into this insertion hole  21  is a pin  22  (corresponding to the pressing member) made of synthetic resin. Though described later in details, this pin  22  presses the inner circumference of the housing member  16  toward the outer circumference of the wire  13 . Additionally, the pin  22  inserted into the insertion hole  21  in near the center in the right and left direction in  FIG. 7  penetrates through gaps in the metal thin wires composing the braided wire  12 . 
     As shown in  FIG. 8C , the pin  22  comprises an axis part  23  extending up and down in  FIG. 8C  and a flat part  24  positioned in the upper end of the axis part  23  and formed in a flat shape of a diameter larger than that of the axis part  23 . In the axis part  23 , from the position close to the lower end thereof, a pair of fall-out preventing pieces  25  is provided so as to extend diagonally upward left and upward right. The fall-out preventing piece  25  is capable of elastic deformation. 
     The axis part  23  of the pin  22  inserted into the insertion hole  21  that is positioned near the both right and left ends of the sleeve pipe  11  in  FIG. 7  is designed so as to have a shorter height than that of the axis part  23  of the pin  22  inserted into the insertion hole  21  that is positioned near the center in the right and left direction of the sleeve pipe  11 . 
     As shown in  FIG. 7 , with the pin inserted into the insertion hole  21  from up to down, the opposing walls  20  each other are held between the bottom surface of the flat part  24  of the pin  22  and the upper end of the fall-out preventing piece  25 , and thereby fixed in a vertically pressed-state by elastic repulsive force of the fall-out preventing piece  25 . This causes the groove  18  positioned upper side in  FIG. 7  to be pressed downwardly and forced on the upper half of the outer circumference of the wire  13 . On the other hand, the groove  18  positioned lower side in  FIG. 7  is pressed upwardly and forced onto the lower half of the outer circumference of the wire  13 . With this configuration, the inner circumference of the housing member  16  constituted by the grooves  18  is pressed toward the outer circumference of the wire  13 . Accordingly, the braided wire  12  is held between the inner circumference of the housing member  16  and the outer circumference of the wire  13 , and thus, the inner circumference of the first housing member  16  adheres tightly to the braided wire  12 , while the braided wire  12  adheres tightly to the outer circumference of the wire  13 . 
     Next, a manufacturing method of the shield conductor  10  according to the present embodiment is described. Firstly, the plate member  17  is formed by extruding a synthetic resin as shown in  FIG. 2 . The insertion hole  21  formed in the opposing wall  20  may be shaped at the time of extrusion, or be shaped by punching with a jig not shown after forming the plate member  17 . 
     Next, as shown in  FIG. 4 , the wire  13  is run through inside of the braided wire  12 . After that, as shown in  FIGS. 5 and 6 , the plate member  17  is folded at the folding member  19  so as to hold the wire  13  and the braided wire  12 . 
     When the plate member  17  is folded at the folding member  19 , the housing member  16  is formed by the grooves  18  formed in the plate member  17 . The plate member  17  is folded so as to separately house the wire  13  within this housing member  16 . 
     After that, as shown in  FIGS. 8A ,  8 B, and  8 C, the pin  22  is inserted into the insertion hole  21  in the opposing wall  20 . From above the insertion hole  21  that is vertically communicating, the pin  22  is pushed downwardly, with its flat part  24  positioned upwardly (see  FIG. 8A ). When the lower part of the axis part  23  is inserted into the insertion hole  21 , the fall-out preventing piece  25  provided in a position closer to the lower end of the axis part  23  is pressed by the inner circumferential surface of the insertion hole  21 , and thereby elastically deforming in the closing direction of a pair of the fall-out preventing pieces  25  (see  FIG. 8B ). When the pin  22  is further pushed downwardly, a pair of the fall-out preventing pieces  25  recoveringly deforms in its opening direction (see  FIG. 8C ). Then, the bottom surface of the flat part  24  of the pin  22  and the upper surface of the opposing wall  20  positioned upper side are abutted on each other from above and below, while the upper end of the fall-out preventing piece  25  and the bottom surface of the opposing wall  20  positioned lower side are abutted on each other from above and below. This holds the opposing wall  20  between the flat part  24  and the fall-out preventing piece  25  in the pin  22 . The opposing wall  20  is pressed vertically in  FIG. 8C  due to the elastic repulsive force of the fall-out preventing piece  25 . Accordingly, the plate member  17  is fixed in a prevented-state of opening deformation in up and down direction. Accordingly, the shield conductor  10  is completed. 
     Next, working and effect of the present embodiment is described. Heat generated from the wire  13  when electrical current is fed to the wire  13  is transmitted from the wire  13  to the braided wire  12 , and to the sleeve pipe  11 , and then is released from the sleeve pipe  11  to the outside of the shield conductor  10 . According to the present embodiment, the outer circumference of the wire  13  and the braided wire  12  tightly adhere each other, while the braided wire  12  and the inner circumference of the sleeve pipe  11  tightly adhere each other. Accordingly, the heat conductivity from the wire  13  to the sleeve pipe  11  can be improved, thereby improving the heat dissipation property of the shield conductor  10 . 
     In addition, the braided wire  12  is constituted by weaving a metal thin wire, and an air layer exists in gaps of the metal thin wires in the braided wire  12 . Therefore, heat is concerned to remain inside of the braided wire  12 . In the present embodiment, the braided wire  12  adheres tightly to the wire  13  as well as to the sleeve pipe  11 , so that heat generated from the wire  13  is transmitted directly from the wire  13  to the braided wire  12 , and then directly from the braided wire  12  to the sleeve pipe  11 . As a result, this can suppress heat from remaining within the braided wire  12 . 
     Furthermore, according to the present embodiment, the inner circumference of the sleeve pipe  11  is pressed toward the outer circumference of the wire  13  by the pin  22 . This enables the inner circumference of the sleeve pipe  11  and the braided wire  12 , and also the braided wire  12  and the outer circumference of the wire  13 , to be surely adhered each other. 
     Moreover, multiple of wires  13  are separately housed in the housing members  16  in the sleeve pipe  11 , in a state aligned in a direction orthogonal to their axial direction at intervals. This can suppress heat generated from the wire  13  from remaining in between adjacent wires  13 . 
     And also, multiple wires  13  are collectively shielded in the present embodiment, thereby achieving cost reduction. 
     Additionally, in the present embodiment, the sleeve pipe  11  is constituted by folding one plate member  17  at nearly the center and uniting thereof. This allows the sleeve pipe  11  to be formed from one plate member  17 , and thereby achieving reduction in the number of parts. 
     Additionally, the sleeve pipe  11  is made of synthetic resin, and can be reduced in weight and production cost, in comparison with the sleeve pipe  11  made of a metal. 
     Embodiment 2 
     Next, in reference to  FIGS. 9 and 10 , Embodiment 2 of the present invention is described. In the present embodiment, unlike the shield conductor  10  according to Embodiment 1, the plate member  17  omits the folding member  19  and the opposing wall  20  provided in a manner so as to continue to the folding member  19 . Accordingly, the pin  22  pressing and fixing the opposing walls  20  provided in a manner so as to continue to the folding member  19  in Embodiment 1 is also omitted. 
     In addition, the groove  18  formed in a position in the right end of the plate member  17  in  FIG. 10  is vertically joined, with its cross-section in nearly a circular shape. The configurations other than the above are nearly the same as Embodiment 1, and thus, the same numerals are allotted to the same members, so that a repetitive description thereof is omitted. 
     According to the present embodiment, the folding member  19 , the opposing wall  20  provided in a manner so as to continue to the folding member  19 , and the pin  22  for fixing the opposing walls  20  can be omitted, and thereby simplifying the structure of the sleeve pipe  11 . 
     Embodiment 3 
     Next, in reference to  FIG. 11 , Embodiment 3 of the present invention is described. In the present embodiment, each wire has the insulating coating  15  enwrapping the outer circumference of the core wire  14 , while the braided wire  12  enwraps the outer circumference of this insulating coating  15 . This allows each wire  13  to be enwrapped separately by the braided wire  12 . 
     The opposing wall  20  positioned in above and the opposing wall  20  positioned in below in  FIG. 11  are vertically abutting. The vertical lengths of all the pins  22  inserted into the insertion holes  21  formed in the opposing wall  20  are designed to be the same. 
     The configurations other than the above are nearly the same as Embodiment 1, and thus, the same numerals are allotted to the same members so as to omit repetitive descriptions thereof. 
     In the present embodiment, an existing shielding wire can be used as the wire  13 . 
     And also, the opposing walls  20  each other are abutting vertically, and not holding the braided wire  12  there between. Therefore, heat generated from the wire  13  does not remain in the gaps in the metal thin wires composing the braided wire  12 . As a result, the heat dissipation property of the shield conductor  10  is improved. 
     Embodiment 4 
     Next, in reference to  FIG. 12 , Embodiment 4 of the present invention is described. The sleeve pipe  11  is formed by uniting a first plate member  26  positioned above and a second plate member  27  positioned in below in  FIG. 12 . The first plate member  26  is made of synthetic resin, having three first grooves  28  aligned in the right and left direction in  FIG. 12  and formed so as to be recessed upwardly. The cross-sectional shape of the first groove  28  is semicircular. 
     The second plate member  27  is made of synthetic resin, having three second grooves  29  aligned in the right and left direction and formed so as to be recessed downwardly. The cross-sectional shape of the second groove  29  is semicircular. 
     The first plate member  26  and the second plate member  27  are in the same shape, though illustrated as being inverted up and down in  FIG. 12 . 
     The first and the second grooves  28  and  29  are formed in positions opposing each other in a united state of the first plate member  26  and the second plate member  27 . The opposing grooves  28  and  29  are forming the housing member  16  for housing the wire  13  and the braided wire  12 . 
     The configurations other than the above are nearly the same as Embodiment 1, and thus, the same numerals are allotted to the same members so as to omit repetitive descriptions thereof. 
     According to the present embodiment, the sleeve pipe  11  can be formed from the first and second plate members  26  and  27  in the same shape, and thereby achieving cost reduction compared to the case where the sleeve pipe  11  is constituted by uniting plate members having different shapes. 
     Other Embodiments 
     With embodiments of the present invention described above with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and the embodiments as below, for example, can be within the scope of the present invention. 
     (1) In Embodiment 4, both the first and the second plate members  26  and  27  are made of synthetic resin, however, the present invention is not limited to this, and for example, the first plate member  26  may be made of synthetic resin, while the second plate member  27  is made of a metal. In this case, when arranging the shield conductor  10  on, for example, the bottom surface (under the floor) of a vehicle, the second plate member  27  is provided as facing downward so as to protect the wire  13  from collision with foreign objects. Additionally, both the first and second plate members  26  and  27  may be made of a metal.
 
(2) In the present embodiment, the shielding layer is represented by the braided wire  12 , however, the present invention is not limited to this, and the shielding layer may be formed by, for example, twisting a metallic tape around the outer circumference of the wire  13 .
 
(3) As a pressing member, for example, a rivet may be used, and any members capable of pressing the inner circumference of the sleeve pipe  11  toward the outer circumference of the wire  13  may be used. Additionally, the sleeve pipe  11  is fixed by the pin  22  in Embodiment 3, however, the plate members may be united and fixed by heat sealing or an adhesive.
 
(4) In the present embodiment, the sleeve pipe  11  houses three wires  13 , however, the present invention is not limited to this, and the sleeve pipe  11  may house multiple wires  13 , two or four and more.