Patent Publication Number: US-6991493-B2

Title: Shielded wire-connecting structure

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a shielded wire-connecting structure which is used in an electric car or the like, and causes electromagnetic waves, transmitting along a shielded wire, to escape to the exterior, and also to block electromagnetic waves from the exterior so as to eliminate adverse effects of such electromagnetic waves on an equipment. 
     2. Related Art 
     Many equipments, such as a motor, are mounted on a vehicle (serving as a mobile structure) such as an automobile, and adverse effects of electromagnetic waves, generated from these equipments and wires, have now been at such a level that these effects can not be ignored. Particularly, adverse effects of electromagnetic waves, generated from large-current/high-voltage equipments, have become a problem. Therefore, the equipments and wires have been protected from electromagnetic interference by the use of a suitable method such as an electromagnetic shielding method although the countermeasures are different depending on the source of generation of electromagnetic waves and the kind of electromagnetic waves. 
     A wire having a shielding layer provided around its conductor, that is, a so-called shielded wire (or shielded cable), has been extensively used as a wire for supplying electric power to an on-vehicle equipment and also as a wire for transmitting and receiving signals. Particularly, a wire, having a thin design for lightweight purposes, is liable to be affected by electromagnetic waves, and a shielded wire has been used as such a wire. 
       FIG. 6  is one example of the art related to a structure of connecting a shielded wire of this kind shown in Unexamined Utility Model Publication Hei. 6-58560. This shield connector  100  includes a shielded wire  122 , a metal terminal  115  of a cylindrical shape press-fastened to an end portion of the shielded wire  122 , and an insulative connector housing  101  having a terminal receiving chamber  106 . 
     The shielded wire  122  includes a conductor  122   a  provided at a center or axis thereof, a braided wire  122   c  provided around the conductor  122   a  through an inner insulating covering  122   b , and an outer insulating sheath  122   d  forming an outermost layer. The metal terminal  115  is a so-called round pin formed by cutting a material of copper or a copper alloy. An electrical contact portion  117 , having a bolt hole  117   a , is formed at a front half of this metal terminal  115 , while a wire connection portion  119 , having a conductor insertion hoe  119   a , is formed at a rear half thereof, and the two portions  117  and  119  are separated from each other by a partition wall  116  formed at a central portion of the metal terminal. An equipment-side terminal  127 , press-fastened to a power connection cable  126  of an on-vehicle equipment, is fastened to the electrical contact portion  117  by a fastening bolt  130 . 
     An end portion of the conductor  122   a , exposed by removing the inner insulating covering  122   b , is inserted into the conductor insertion hole  119   a  in the metal terminal  119 , and is fixedly connected to the wire connection portion  119  by press-deforming this wire connection portion  119 . A waterproof rubber plug  131  is fitted on an end portion of the braided wire  122   c  exposed by removing the outer insulating sheath  122   d . A rubber plug holder  132  is fitted on the insulated wire, and is disposed at a rear side of the waterproof rubber plug  131 . A connecting member  112  of an electrically-conductive nature is provided at the front side of the waterproof rubber plug  131 , and is held in contact with the braided wire  122   c.    
     The connector housing  101  includes a cylindrical housing body  105 , a shield shell  110  which is integrally molded in the housing body  105 , and serves also as a grounding contact, and a flange portion  111  formed on and around an outer surface of the shield shell  110 . 
     The housing body  105  has the terminal receiving chamber  106  having open opposite ends, and an outer wall of the housing body  105  is divided into a front half reduced-thickness portion and a rear half thickened portion, with a stepped portion formed at the boundary between the reduced-thickness portion and the thickened portion. The flange portion  111  is formed at the stepped portion over an entire periphery thereof, and is disposed perpendicularly to the outer wall. 
     The shield shell  110  has a generally L-shape or inverted L-shape as a whole, and includes a cylindrical tubular portion  110   a , and a flange  110   b  extending generally perpendicularly from one end of the tubular portion  110   a . The tubular portion  110   a  is integrally molded in the outer wall of the housing body  105  as described above. A distal end portion of the tubular portion  110   a  is resiliently contacted with the connecting member  112  resiliently supported on the waterproof rubber plug  131 . The flange  110   b  for grounding purposes is exposed at the front side of the flange portion  111 , and is held between a casing  125  and the flange portion  111 . 
     The casing  125  is an electrically-conductive wall portion of the on-vehicle equipment such as a motor, and this casing  125  has a mounting hole  125   a  for the connector housing  101 , and also has bolt holes  125   b  for the flange portion  111 . The flange  110   b  of the shield shell  110  is held between the casing  125  and the flange portion  111 , and then bolts  121  (serving as fastening members) are inserted respectively into the bolt holes  125   b , and by doing so, the flange  110   b  and the casing  125  are held in contact with each other, thereby connecting the shielded wire  122  to the ground. 
     Another conventional example is a shielded wire-connecting structure using the fitting connection between male and female connectors Unexamined Japanese Patent Publication 2002-117947. In this conventional example, the connection of wire to a base wall for grounding purposes can be effected stably without incurring a permanent set, wear, etc., of a resilient contact portion, and a good shielding performance can be maintained, and also the shielding performance can be enhanced. A shield shell, joint terminals, an outer housing and a flange portion are formed of a non-magnetic material having electrical conductivity. The joint terminal is provided in contact with a connector entry-side inner wall surface of the outer housing, the shield shell is provided at the male connector, and the shield shell is connected at one side portion to braided wires of shielded wired, and is connected at the other side portion to the joint terminals, and the flange portion of the outer housing is fixedly connected by bolts to a electrically-conductive connector mounting wall of an equipment. 
     With respect to other conventional examples, there is known a structure in which a shield connector is covered with an electrically-conductive cover, and an electrically-conductive grommet is mounted on a distal end portion of a shielded wire in intimately-contacted relation thereto, and with this construction the connection of the shielded wire can be effected easily, and a waterproof performance is enhanced as shown in Unexamined Japanese Patent Publication Hei. 7-193966. There is also known a structure in which shielded wires, introduced from the exterior via respective grommets, are connected to a non-waterproof joint connector located within an auxiliary equipment box of a sealed structure, and with this construction the processing of the shielded wires can be effected easily as shown in Unexamined Japanese Patent Publication 2000-184556. 
     However, the above conventional shielded wire-connecting structures have the following problems to be solved. 
     In the first conventional example, when a plurality of shielded wires  122  were to be connected to the equipment, the casing  125  was required to have a large area to which the flange  110   b  of the shield shell  110  was to be connected, and therefore there was encountered a problem that the shield connector  100  could not be mounted on the casing. 
     And besides, the metal terminal  115 , having the electrical contact portion  117  at one side of the partition wall  116  and the wire connection portion  119  at the other side of the partition wall, was received in the shield connector  100 , and therefore the overall length of the shield connector  100  was large, and this invited a problem that the shield connector  100  had a large size. Particularly in the case of a multi-pole shield connector receiving a plurality of terminals, the number of component parts was large, and therefore the shield connector became unduly large, and in some cases, the shield connector could not be easily mounted on an equipment installed in a smaller space, for example, under a floor. 
     The flange  110   b  of the shield shell  110  and the bolt  130  were exposed to the outside of the casing  125 , and therefore there was a fear that these were corroded by water, intruding from the exterior, and dew condensation, so that the shielding performance was adversely affected. 
     In the second conventional example, the connection between the shielded wire and the equipment was effected by the connector-connection between the male and female connectors, so that the connection could be effected with a one-touch operation. However, the connecting structure was complicated, and increased in size, so that the shield connector could not be easily mounted in a limited mounting space, thus inviting a problem that the efficiency of the mounting operation was low. 
     In the third conventional example, the waterproof grommet was mounted on each shielded wire, and therefore when a plurality of shielded wires were used, the shielded wire-connecting structure became complicated, thus inviting a problem that the structure became large in size. 
     In the fourth conventional example, the connector was connected to the end portions of the shielded wires introduced into the auxiliary box via the respective grommets, and therefore as in the first conventional example, there was encountered a problem that the number of the component parts was large, so that the shielded wire-connecting structure became large in size. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, it is an object of this invention to provide a shielded wire-connecting structure in which the connecting structure can be formed into a compact design, and besides each shielded wire can be connected to the ground without requiring an undue operation space, and furthermore a waterproof performance of a connected portion between each shielded wire and an equipment can be enhanced. 
     A first object has been achieved by a shielded wire-connecting structure of the present invention wherein a braided wire of a shielded wire is connected for grounding purposes to a shielding cover via a joint terminal which includes a wire connection portion formed at one end thereof so as to be connected to the braided wire, and a terminal mounting portion formed at the other end thereof so as to be connected to the shielding cover; provided in that a passage hole for the passage of a fastening member therethrough is formed through the terminal mounting portion, and the terminal mounting portions of a plurality of the joint terminals are superposed together, with the passage holes communicating with each other, and are fastened together to the shielding cover by the fastening member passing through the passage holes. 
     In the above construction, when the braided wire of each shielded wire is connected to the shielding cover via the joint terminal, and the shielding cover is fixed to a grounding portion of an equipment, electromagnetic waves, transmitting along the shielded wire, are grounded to the equipment, so that adverse effects of the electromagnetic waves on the equipment are eliminated. When the shielded wire is covered with the shielding cover, external electromagnetic waves are prevented from propagating to the equipment by radiation and conduction, and this also eliminates adverse effects of the electromagnetic waves on the equipment. The terminal mounting portions of the plurality of joint terminals are superposed together, and with this arrangement the area of contact of the terminal mounting portions with the shielding cover is reduced. 
     According to a second aspect of the present invention, there is provided a shielded wire-connecting structure wherein a braided wire of a shielded wire is connected for grounding purposes to a grounding portion of an equipment via a joint terminal which includes a wire connection portion formed at one end thereof so as to be connected to the braided wire, and a terminal mounting portion formed at the other end thereof so as to be connected to the grounding portion; provided in that a passage hole for the passage of a fastening member therethrough is formed through the terminal mounting portion, and the terminal mounting portions of a plurality of the joint terminals are superposed together, with the passage holes communicating with each other, and are fastened together to the grounding portion by the fastening member passing through the passage holes. 
     In the above construction, the terminal mounting portions of the plurality of joint terminals are superposed together, and with this arrangement the area of contact of the terminal mounting portions with the grounding portion of the equipment is reduced. And besides, the braided wires can be connected for grounding purposes to the equipment before mounting the shielding cover which covers the connected portion between each shielded wire and the equipment. 
     The shielded wire-connecting structure of a third aspect of the present invention, depending from the first or second aspect of the present invention is provided in that a retaining portion is formed at one of the terminal mounting portions which are to be superposed together, and an engagement portion for engagement with the retaining portion is formed at the other terminal mounting portion. 
     In the above construction, the retaining portion and engagement portion of the superposed terminal mounting portions are engaged with each other, and by doing so, the joint terminals can be beforehand combined together. And besides, even when an unnecessary pulling force acts on the shielded wire, the superposed joint terminals are prevented from being disengaged from the shielding cover or the grounding portion. 
     The shielded wire-connecting structure of a fourth aspect of the present invention, depending from any one of the first to third aspect of the present invention, is provided in that the joint terminal is bent into a generally L-shape. 
     In the above construction, the joint terminals are prevented from projecting outwardly, and any special processing does not need to be applied to the shielding cover. 
     As described above, in the first aspect of the present invention, the plurality of joint terminals are superposed together, and are fastened together to the shielding cover, and therefore the shielded wire-connecting structure can be formed into a compact design, and the area of contact of the terminal mounting portions with the shielding cover is reduced, and the shielded wires can be connected to the equipment even in a narrow mounting space. 
     In the second aspect of the present invention, the terminal mounting portions of the plurality of joint terminals are superposed together, and therefore the area of contact of the terminal mounting portions with the grounding portion of the equipment is reduced. And besides, after the braided wires are connected for grounding purposes to the equipment, and conductors of the shielded wires are electrically connected to the equipment, the shielding cover is mounted to cover the connected portion between each shielded wire and the equipment. Therefore, the shielded wire-connecting structure can be formed into a compact design, and the shielded wire-connecting operation can be carried out even in a narrow mounting space. And besides, the efficiency of the operation for connecting the shielded wires to the equipment is enhanced. 
     In the third aspect of the present invention, the retaining portion and engagement portion of the superposed terminal mounting portions are engaged with each other, and by doing so, the joint terminals can beforehand be combined together. Therefore, the operator does not need to pass the fastening member through the passage holes in the terminal mounting portions while aligning these passage holes with each other, and the mounting of the joint terminals on the shielding cover or the grounding portion of the equipment can be effected easily. 
     In the fourth aspect of the present invention, the joint terminal is bent into a generally L-shape, and therefore the joint terminals are prevented from projecting outwardly, and any special processing does not need to be applied to the shielding cover. Therefore, similar effects to those of the first aspect of the present invention are achieved, and besides the shielded wire-connecting structure can be formed into a compact design, the shielded wires can be connected to the equipment even in a narrow mounting space. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a first embodiment of a shielded wire-connecting structure of the invention. 
         FIG. 2  is a perspective view showing a condition in which terminal mounting portions of joint terminals of  FIG. 1  are superposed together. 
         FIG. 3  is a front-elevational view showing the condition in which the terminal mounting portions of the joint terminals are superposed together. 
         FIG. 4  is a front-elevational view showing a modified example of the shielded wire-connecting structure of the invention. 
         FIG. 5  is a perspective view showing a second embodiment of a shielded wire-connecting structure of the invention. 
         FIG. 6  is a cross-sectional view showing one example of conventional shielded wire-connecting structures. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention will now be described in detail with reference to the drawings. 
       FIGS. 1 to 3  show a first embodiment of a shielded wire-connecting structure of the invention, and  FIG. 4  shows a modified example thereof, and  FIG. 5  shows a second embodiment. 
     Adverse effects of electromagnetic waves on an actuator (equipment), such as a motor, an inverter, an electronic control unit and a fuel injection device, mounted on an electric car, have now been at such a level that these effects can not be ignored. The shielded wire-connecting structure of the invention is designed to protect such an actuator from electromagnetic interference, that is, mainly from high-frequency electric and magnetic fields, to prevent a malfunction, thereby maintaining a safe travel of the car for a long period of time. 
     In the shielded wire-connecting structure of this embodiment, this connecting structure can be formed into a compact design, and besides the efficiency of an operation for connecting shielded wires to an actuator can be enhanced. The structure of connecting the shielded wires  37  comprises the shielded wires  37  each including a conductor  37   a  and a braided wire  37   c  provided around the conductor  37   a , and a shield shell (shielding cover)  25  for shielding end portions of the shielded wires  37 . This shielded wire-connecting structure is provided mainly in that the braided wires  37   c  of the shielded wires  37  are connected to the shield shell  25  respectively via joint terminals  10  and  15 , each of the joint terminals  10  and  15  including a wire connection portion  13 ,  18  formed at one end thereof so as to be press-fastened to the braided wire  37   c , and a terminal mounting portion  12 ,  17  formed at the other end thereof so as to be fixedly fastened to the shield shell  25 , that a passage hole  12   a ,  17   a  for the passage of a fastening bolt (fastening member)  19  therethrough is formed through the terminal mounting portion  12 ,  17 , and that the plurality of joint terminals  10  and  15  are superposed together, with the passage holes  12   a  and  17   a  communicating with each other, and are fastened together to the shield shell  25  by the fastening bolt  19  passing through the passage holes  12   a  and  17   a.    
     The main constituent portions of the shielded wire-connecting structure, as well as their operations, will be described below in detail.  FIG. 1  shows the connecting structure for the shielded wires  37  connected to a motor  34  mounted under a floor of an electric car. The two shielded wires  37  and  37  are connected to the motor  34 . Incidentally, the present invention can be applied to a three-phase AC motor operated by three single-phase currents. In the case where there are provided three shielded wires  37 , the terminal mounting portions  12  and  17  of the joint terminals  10  and  15  can be fastened together to the shield shell  25  as is the case with the structure using the two shielded wires  37 . 
     The shielded wire (or shielded cable)  37  is of a four-layer construction, and includes the conductor (or core wire)  37   a  provided at the center or axis thereof, the braided wire  37   c  provided around the periphery of the conductor  37   a  through an inner insulating covering  37   b , and an outer insulating sheath  37   d  provided around the periphery of the braided wire  37   c . Therefore, in the shielded wire  37 , the conductor  37   a , the inner insulating covering  37   b , the braided wire  37   c  and the outer insulating sheath  37   d  are arranged coaxially sequentially from the inner side. 
     A constituent material for the conductor  37   a  is not particularly limited, and any suitable known conductive material can be used. For example, a soft copper wire, a tinned copper wire, a nickel-plated copper wire or the like can be used. The metal-plated copper wires are enhanced in corrosion resistance and heat resistance, and also are protected against reaction with the insulating covering (or coating)  37   b , and therefore have an advantage that their electrical properties can be maintained for a long period of time. 
     The inner insulating covering  37   b  and the outer insulating sheath  37   d  are made of a polymeric material such as a polyvinyl chloride resin, a polyethylene resin and a polypropylene resin. Depending on the kind of the resin material, a plasticizer is added, or a crosslinking treatment is applied. 
     The braided wire  37   c  is made of a tinned soft copper wire or the like having an excellent shielding performance, and this braided wire is formed by weaving wire elements into a tubular shape. The braided wire is stretchable, and can be easily turned back along the inner insulating covering  37   b.    
     At the end portion of the shielded wire  37 , the inner insulating covering  37   b  is removed over a predetermined length to expose the conductor  37   a , and also the outer insulating sheath  37   d  is removed over a predetermined length to expose the braided wire  37   c . A wire connection portion  22  of an LA terminal  20  is press-fastened to the conductor  37   a , and the wire connection portion  13 ,  18  of the joint terminal  10 ,  15  is press-fastened to the braided wire  37   c.    
     The LA terminal  20  is formed by blanking a piece from an electrically-conductive sheet and then by bending it into a crank-shape. This LA terminal is known as an automotive eyelet terminal of JIS D5403. In the present invention, the LA terminals  20  can be replaced by LE terminals (automotive spade terminals). 
     A terminal mounting portion  21  for being fixedly fastened to the motor  34  is formed at one end of the LA terminal  20 , while the wire connection portion  22  for being fastened to the conductor  37   a  of the shielded wire  37  is formed at the other end thereof. A passage hole is formed through the terminal mounting portion  21  at the center thereof, and this passage hole is aligned with a hole  34   b  formed in an electrode portion  34   a  of the motor  34 , and in this condition a fastening bolt  35  is tightened, thereby connecting the terminal mounting portion  21  to the motor  34 . The wire connection portion  22  has a pair of opposed press-clamping piece portions  22   a  and  22   a , and these press-clamping piece portions  22   a  and  22   a  are press-deformed inwardly toward each other to be press-fastened to the conductor  37   a.    
     The conventional metal terminal  115 , shown in  FIG. 6 , is the pin-like terminal formed by cutting a material, and therefore is longer than the LA terminal  20  of this embodiment, and hence had a problem that the overall length of the shield connector  100  became large. In this invention, however, the LA terminals  20 , bent into a crank-shape, are used, and this also enables the compact design of the connecting structure for the shielded wires  37 . 
     Each of the joint terminals  10  and  15  is formed by blanking a piece from an electrically-conductive sheet and then by folding it double and then by bending it into an L-shape, thereby providing an integral construction ( FIGS. 2 and 3 ). The joint terminals  10  and  15  are thus formed into an L-shape, and therefore are prevented from projecting outwardly from the motor  34 , and any special processing does not need to be applied to the shield shell  25 . 
     The wire connection portion  13 ,  18  for connection to the braided wire  37   c  of the shielded wire  37  is formed at one end of the joint terminal  10 ,  15 , while the terminal mounting portion  12 ,  17  for connection to the shield shell  25  is formed at the other end thereof. The wire connection portion  13 ,  18  has a tubular shape, and is inwardly press-deformed uniformly over an entire periphery thereof to be press-fastened to the braided wire  37   c . The terminal mounting portion  12 ,  17  has a plate-like shape, and has the passage hole  12   a ,  17   a  for the passage of a shank portion of the fastening bolt  19 . The joint terminals  10  and  15 , connected to the plurality of shielded wires  37 , are superposed together with the passage holes  12   a  and  17   a  (formed respectively through the terminal mounting portions  12  and  17 ) communicating with each other, and the joint terminals  10  and  15  are fastened together to the shield shell  25  by tightening the fastening bolt  19  passing through the passage holes  12   a  and  17   a.    
     As shown in  FIG. 3 , an operation space a, required for fastening the terminal mounting portions  12  and  17  by the common bolt to the shield shell  25 , is smaller than an operation space which would be needed in the case where the terminal mounting portions  12  and  17  are not fastened together to the shield shell  25 , but are fastened to the shield shell  25  separately from each other by respective bolts. Therefore, the bolt can be fastened in the narrow limited space near to the motor  34 . 
     The shield shell  25  is formed by blanking a piece from a non-magnetic and electrically-conductive aluminum alloy sheet and then by bending it. The constituent material of the shield shell  25  is not limited to such an aluminum alloy, but any other suitable material, such for example as a copper alloy and a synthetic resin material having an electrically-conductive coating formed thereon, can be used in so far as it has excellent shielding properties. Steel is not preferred since its shielding performance is low. A synthetic resin material, not subjected to any treatment, is not suitable since it allows electromagnetic waves to transmit therethrough. 
     The shield shell  25  covers the end portions of the shielded wires  37  and the electrode portions  34   a  of the motor  34  to shield these portions to prevent electromagnetic waves from being transmitted from the exterior to the motor  34 . A fixing portion  25   a  is formed at a front side of the shield shell  25 , and this fixing portion  25   a  is bolt-fastened to an earth cover  34   c  of the motor  34 . A fixing portion  25   d , having a hole  25   b  (through which the joint terminals  10  and  15  are fastened together to the shield shell), and an opening  25   c  (through which the shielded wires  37  are inserted), continuous with the fixing portion  25   d , are formed at a rear portion of the shield shell ( FIG. 1 ). 
     A grommet  27  is an elastic member of an insulating nature for waterproof purposes, and by injection molding, this grommet is integrally molded into such a shape as to cover the outside of the shield shell  25 . A fixing member  29  is held against a flange portion  27   a  formed at a front side of the grommet  27 , and in this condition this fixing member  29  is fixed to the earth cover  34   c  by bolts. Similarly, a fixing member  30  is held against a rear flange portion  27   b  of the grommet  27 , and in this condition this fixing member  30  is fixed to the earth cover  34   c.    
     Those potions of the shielded wires  37 , disposed outwardly of the shield shell  25 , extend respectively through bellows portions  28  of the grommet  27  to the exterior of the grommet  27 . A mouth portion  28   a  of each bellows portion  28  has a diameter smaller than the outer diameter of the shielded wire  37 , and therefore the shielded wire  37  is held in intimate contact with the mouth portion  28   a  to achieve a water-stop effect so that water, moving along the shielded wire  37 , will not intrude into the interior of the grommet. A tape can be wound on the mouth portion  28   a  of each bellows portion  28  so as to further enhance the water-stop effect. 
     As described above, the shielded wires  37  in the present invention are connected to the motor  34  installed under the floor of the electric car, and therefore are less liable to be adversely affected by water as compared with shielded wires connected to an actuator within an engine room. Aside from this, a gap between the shield shell  25  and the earth cover  34 , as well as a gap between each shielded wire and the earth cover  34   c , is completely sealed, and therefore the connected portion between each shielded wire  37  and the corresponding joint terminal  10 ,  15 , the connected portion between each shielded wire  37  and the corresponding LA terminal  20  and the connected portion between each LA terminal  20  and the motor  34  are positively protected in a waterproof manner, so that the reliability of the electrical connection is enhanced. 
     Next, the modified example of this embodiment will be described with reference to  FIG. 4 . Identical constituent portions to the joint terminals  10  and  15  of  FIGS. 1 to 3  will be designated by identical reference numerals, respectively, and explanation thereof will be omitted. In this modified example, the efficiency of an operation for connecting shielded wires  37  can be enhanced, and terminal mounting portions  12  and  17  of joint terminals  10 ′ and  15 ′ are superposed together, with passage holes  12   a  and  17   a  communicating with each other, and are fastened together to a grounding portion  14  of an earth cover  34  by a fastening bolt  19  passing through the passage holes  12   a  and  17   a . As a result, braids  37   c  of the shielded wires  37  are connected for grounding purposes to the grounding portion  14 , and after conductors  37   a  of the shielded wires  37  are connected respectively to electrode portions  34  of a motor  34 , a shield shell  25  can be mounted to cover the motor  34 , and therefore the connection of the shielded wires  37  can be effected easily. 
     Like the joint terminals  10  and  15  shown in  FIG. 3  and other Figures, each of the joint terminals  10 ′ and  15 ′ is formed by folding a blanked-out sheet piece (in a developed condition) double and then by bending it, thereby providing an integral construction. A wire connection portion  13 ,  18  of a tubular shape is formed at one end of each joint terminal  10 ′,  15 ′ while the terminal mounting portion  12 ,  17 , having the passage hole  12   a ,  17   a , is formed at the other end thereof. 
     A hole for the passage of a shank portion of the fastening bolt  19  is formed through the grounding portion  14 , and a female screw portion  14   b  is formed on and projects downwardly from a peripheral edge of this hole. With this construction, it is not necessary to provide a nut at the reverse side of the earth cover  34   c  when the joint terminals  10 ′ and  15 ′ are to be bolt-fastened to the grounding portion  14 , and this also enhances the efficiency of the operation for connecting the shielded wires  37 . 
     An operation space b, required for the bolt-fastening operation, is generally equal to the operation space a shown in  FIG. 3 , and the terminal mounting portions  12  and  17  of the joint terminals  10 ′ and  15 ′ can be fastened by the bolt in the narrow limited space. 
     Next, the second embodiment of the invention will be described with reference to  FIG. 5 . This embodiment is provided in that retaining step portions (retaining portions)  42   d  are formed at a terminal mounting portion  42  (which is one of two terminal mounting portions  42  and  47  to be superposed together), while engagement step portions (engagement portions)  47   d  for engagement respectively with the retaining step portions  42   d  are formed at the other terminal mounting portion  47 . 
     Each of joint terminals  40  and  46  is formed by blanking a piece from an electrically-conductive sheet and then by bending it into a predetermined shape, thereby providing an integral construction. These joint terminals differ from the joint terminals  10 ,  15 ,  10 ′ and  15 ′ of  FIGS. 3 and 4  in that the blanked-out sheet piece in a developed condition is not folded double, but is bent from its developed condition into the predetermined shape. The joints terminals  40  and  46  further differ from the joint terminals  10 ,  15 ,  10 ′ and  15 ′ of  FIGS. 3 and 4  in that a wire connection portion  41  for being press-fastened around a braided wire  37   c  of a shielded wire  37  is formed at one end of each of the joint terminals  40  and  46  and that the terminal mounting portions  42  and  47  which are adapted to be combined together in biting relation to each other are formed respectively at the other ends of the joint terminals  42  and  47 . 
     The wire connection portion  41  has a tubular wall  41   a  which is curved into a generally round shape, and the tubular wall  41   a  is wound around the braided wire  37   c , and therefore even when the shielded wire  37  of a different size or diameter is used, the wire connection portion  41  can be firmly press-fastened on the shielded wire  37 . Therefore, the braided wire  37   c  and the wire connection portion  41  are contacted with each other in a good condition, so that the contact reliability is enhanced, and also the withdrawal of the shielded wire  37  from the wire connection portion by a pulling force due to vibrations of the car or others is prevented. 
     The one terminal mounting portion  42  includes a passage hole  42   a  of a generally rectangular shape, base plate portions  42   b  and  42   c  disposed respectively on opposite sides of the passage hole  42   a , the pair of retaining step portions  42   d  and  42   d  which are formed between the two base plate portions  42   b  and  42   c , and project upwardly in a direction of the thickness of these base plate portions, and a retaining piece portion  42   e  formed at the base plate portion  42   c . The other terminal mounting portion  47  is so shaped as to be brought into biting engagement with the one terminal mounting portion  42 , and this terminal mounting portion  47  includes a passage hole  47   a  of a generally rectangular shape, base plate portions  47   b  and  47   c  disposed respectively on opposite sides of the passage hole  47   a , the pair of engagement step portions  47   d  and  47   d  which are formed between the two base plate portions  47   b  and  47   c , and project downwardly in a direction of the thickness of these base plate portions, and a retaining groove  47   e  formed in the base plate portion  47   c.    
     Each retaining step portion  42   d  and each engagement step portion  47   d  project respectively in opposite directions, and the base plate portions  42   b ,  42   c ,  47   b  and  47   c  are flat. Therefore, the two terminal mounting portions  42  and  47  can be superposed together, with no gap formed therebetween. When the two terminal mounting portions  42  and  47  are brought into biting engagement with each other, the retaining piece portion  42   e  of the one terminal mounting portion  42  is engaged in the retaining groove  47   e  in the other terminal mounting portion  47 , thereby locking the two terminal mounting portions  42  and  47  to each other. The upper and lower passage holes  42   a  and  47   a  communicate with each other, and a fastening bolt  19  is passed through the passage holes  42   a  and  47   a , and a nut  45  is threaded on this fastening bolt  19 , so that the upper and lower terminal mounting portions  42  and  47  are completely fastened to a shield shell  25 . 
     The other construction of the connecting structure for the shielded wires  37  is generally similar to that of the connecting structure of  FIGS. 1 to 3 , and therefore explanation thereof will be omitted. 
     In this embodiment, the terminal mounting portions  42  and  47  of the joint terminals  40  and  46  are beforehand combined together before the shielded wires  37  are connected to a motor  34 , and therefore it is not necessary to effect the bolt-fastening operation while superposing the terminal mounting portions  42  and  47  of the joint terminals  40  and  46  together, with the passage holes  42   a  and  47   a  communicating with each other, and therefore the joint terminals  40  and  46  can be easily connected for grounding purposes to the shield shell  25 . And besides, the fastening bolt  19  is prevented from being loosened by vibrations of the car and others, and therefore the joint terminals  40  and  46  are prevented from being disengaged from the shield shell. 
     The present invention is not limited to the above embodiments, and various modifications can be made without departing from the subject matter of the invention. The connecting structures of the invention for the shielded wires  37  can applied also to a shield connector.