Patent Publication Number: US-7713101-B2

Title: Male terminal having a U-shaped cross section

Description:
The present application is a divisional application of U.S. application Ser. No. 11/635,766, filed Dec. 8, 2006, which is based upon and claims the benefit of priority from Japanese Patent Application Nos. 2005-380303 and 2005-380304, the entire contents of all of which are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a connector structure having an electric terminal for flowing a large current, in more particularly, to a connector structure having a male terminal and a female terminal in that the male terminal is connected to the female terminal by inserting the male terminal into the female terminal. 
   2. Description of the Related Art 
   Nowadays, HEV (Hybrid Electric Vehicle) attracts a great deal of interest, since the HEV can provide an effect of reducing exhaust of harmful gas and a large fuel saving benefit. A connection between an inverter and a motor for driving the HEV is conducted by a connector, and a large current greater than 100 A may be flown in accordance with the system of the HEV. In accordance with development in electrical control techniques of the vehicles, a large number of connectors have been used for the vehicles. However, there are few kinds of connectors that are suitable for the large current flow. As examples of terminals used for the connectors suitable for the large current, a flat-plate shape male terminal shown in  FIG. 11  and a flat-plate female terminal shown in  FIG. 12  are proposed. 
   As shown in  FIG. 11 , a male terminal  50  composed of a single narrow plate member comprises a wire connecting portion  51  at one end thereof, to be connected to another electrical apparatus (not shown), and an inserting contact portion  52  at another end thereof, to be contact with a female terminal shown in  FIG. 12 . At the wire connecting portion  51 , a device connecting hole  53  for fastening and tightening the male terminal  50  with a bolt to the other apparatus. Dimensions of the male terminal  50  are e.g. a width of about 95 mm and a thickness of about 1.2 mm. 
   As shown in  FIG. 12 , a female terminal  60  formed by bending a plate member comprises a terminal energizing portion  61  for fixing and electrically coupling the male terminal  50  thereto, and a wire clamping portion  62  for connecting an electric wire by clamping. In the terminal energizing portion  61 , a plate spring  63  for fixing the male terminal  50  within the terminal energizing portion  61  is provided. 
   As shown in  FIG. 13 , when the male terminal  50  is inserted into the female terminal  60 , the inserting contact portion  51  of the male terminal  50  is pressed by the plate spring  63  and attached securely into the terminal energizing portion  61 , so that the male terminal  50  and the female terminal  60  are electrically connected with each other. 
   The male terminal  50  and the female terminal  60  shown in  FIGS. 11 to 13  are made of a high conductivity material (i.e. a material having a high electrical conductivity), for example, copper. Among the copper materials, it is preferable to use the high conductivity copper material, so as to suppress generation of heat when the current is flown. 
   However, since a relationship between an electrical conductivity and strength of the terminal material is a trade-off, there is a tendency that the strength of the terminal is reduced when the high conductivity material is used for forming the terminal. 
   For example, if the terminal is formed by using a copper with a conductivity of 90% or more, a desired strength of the terminal cannot be obtained. Accordingly, it is necessary to form the terminal by using a material having a sufficient strength, while sacrificing the conductivity of the terminal material to some extent. 
   Since the female terminal  60  is provided with the spring  63 , it is necessary to select the terminal material with considering that the spring  63  thus formed should have a sufficient elasticity, in addition to the relationship between the conductivity and the strength of the material. 
   The material having excellent characteristics for all of the conductivity, strength, and elasticity is not found currently. However, as the means for solving the above problems, there is proposed a female terminal with a configuration of combining a terminal energizing portion with a high conductivity and a spring with an excellent spring characteristic and a high strength, in which the spring and the terminal energizing portion are fabricated separately and combined with each other. 
   Conventional male terminal structures are disclosed by Japanese Patent No. 2878429 (JP-B-2878429), Japanese patent No. 2993590 (JP-B-2993590), and Japanese Utility Model publication for opposition No. 7-51739 (JP-Y-7-51739). 
   However, since the conventional male terminal  50  shown in  FIG. 11  is composed of a single plate, a surface area there of is small, so that the heat dissipation property is not excellent. Accordingly, there is a disadvantage in that a temperature of the terminal is elevated during the large current flow, thereby influencing on a housing resin or peripheral devices of the connector. 
   Further, there is proposed a male terminal having a hollow structure with a rectangular cross section to increase a surface area and a cross sectional area of the male terminal, so as to enhance the heat dissipation property. However, in the case where the male terminal having the hollow and rectangular shape is used, while the heat dissipation during the current flow can be improved, it is difficult to conduct a bus connection which is typically used in the connection with a component at the device side such as an inverter. It is because that the terminal at the device side may be bent to have an L-shape when used for the bus connection in accordance with the system configuration. In such a case, it is significantly difficult to bend the terminal with the rectangular structure for the bus connection, since cracks may be generated. Therefore, the problems in the conventional male terminal cannot be solved by the hollow and rectangular structure male terminal. In addition, conventional female terminal structures are disclosed by Japanese Patent Laid-Open No. 11-233182 (JP-A-11-233182) and Japanese Patent Laid-Open No. 2005-56792 (JP-A-2005-56792). 
   However, when the conventional female terminal is used as a connector terminal for a vehicle, there is a following disadvantage. The connector terminal for a vehicle may be exposed to a high temperature such as 150° C. In such circumstances, a terminal box (terminal energizing portion  61 ) of the female terminal may be opened when a material composing the terminal has a large stress relaxation property. For example, a plate member bent with an angle of 90° may be deformed in an opposite direction as a result the plate member may be opened to have an angle of around 100°. 
   When the terminal box is opened, a distance between the spring and the terminal box is increased, namely, a space to which the male terminal is inserted is enlarged. In such a case, an amount of displacement applied to the spring is decreased, namely, a contacting force of the spring for pinching the male terminal is reduced, so that the electric apparatus connected via the female terminal  60  does not satisfy a predetermined characteristic. 
   Accordingly, it is necessary to form the female terminal in which the contacting force of the spring is set be high at a normal temperature, with considering an opening angle of the terminal box at the high temperature, such that the predetermined characteristic of the female terminal can be obtained even though the terminal box is opened due to the high temperature. However, when the spring with high contacting force is provided, there is a disadvantage in that a force required for inserting the male terminal into the female terminal (terminal inserting force) is increased, so that the insertion of the male terminal into the female terminal will be difficult. 
   SUMMARY OF THE INVENTION 
   Accordingly, an object of the invention is to provide a connector structure having a male terminal and a female terminal in which the male terminal has an excellent heat dissipation property during the large current flow and a good connection with an external device. 
   Another object of the invention is to provide a connector structure having a male terminal and a female terminal in which the female terminal is provided with a spring which keeps a good contacting force for fixing the male terminal at a high temperature, without increasing a terminal inserting force of the male terminal. 
   According to a first feature of the invention, a male terminal comprises: 
   a wire connecting portion at one end thereof, to be connected to an electric wire; and 
   an inserting contact portion formed by bending a flat-plate member to have a U-shape cross section at another end, to be inserted into a female terminal. 
   In the male terminal, it is preferable that the inserting contact portion includes a bottom plate and projecting pieces projected from both sides of the bottom plate, and that a width of the bottom plate and a height of both of the projecting pieces are substantially same as those of an inner frame of the female terminal. 
   The male terminal may further comprise: 
   a stopper piece to be engaged with a housing of a connector accommodating the male terminal, the stopper piece being projected from a back end of an inserting portion of the projecting pieces. 
   In the male terminal, the inserting contact portion may comprise an inserting end portion having a tapered portion which is narrowed to its end. 
   According to a second feature of the invention, a female terminal comprises: 
   a terminal energizing portion composed of a high conductivity material having a frame structure, for accommodating a male terminal; 
   a terminal box composed of a material having a strength higher than that of the high conductivity material of the terminal energizing portion, for covering the terminal energizing portion; and 
   a spring located within the terminal energizing portion for fixing the male terminal, the spring being formed integrally with the terminal box. 
   The female terminal may further comprise: 
   an opening formed at a surface of the terminal box, the opening being provided with a fixing tab for fixing the terminal energizing portion; 
   an engaging concave portion formed at a surface of the terminal energizing portion for engaging with the fixing tab, the surface of the terminal energizing portion contacting with the surface of the terminal box; 
   in which the terminal box and the terminal energizing portion are fixed with each other by bending the fixing tab into the engaging concave portion. 
   In the female terminal, it is preferable that each of the terminal box and the terminal energizing portion is formed by bending a single plate member to have a substantially rectangular cross section, a joint of the terminal energizing portion is located on a surface opposed to a surface on which a joint of the terminal box is located. 
   According to a third feature of the invention, a connector structure having a male terminal and a female terminal comprises: 
   the male terminal including:
         a wire connecting portion at one end thereof, to be connected to an electric wire; and   an inserting contact portion formed by bending a flat-plate member to have a U-shape cross section at another end, to be inserted into a female terminal; and       

   the female terminal including:
         a terminal energizing portion composed of a high conductivity material having a frame structure, for accommodating the male terminal;   a terminal box composed of a material having a strength higher than that of the high conductivity material of the terminal energizing portion, for covering the terminal energizing portion; and   a spring located within the terminal energizing portion for fixing the male terminal, the spring being formed integrally with the terminal box.       

   According to the present invention, the male terminal can be provided with an excellent heat dissipation property during the large current flow and a good connection with an external device can be realized. 
   Further, according to the present invention, the female terminal can be provided with a spring which keeps a good contacting force for fixing the male terminal even at a high temperature, without increasing a terminal inserting force of the male terminal. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiment according to the invention will be explained in conjunction with appended drawings, wherein: 
       FIG. 1  is a perspective view showing a male terminal of a connector in a preferred embodiment according to the invention; 
       FIG. 2  is a perspective view showing a state where the male terminal of  FIG. 1  is inserted into a female terminal; 
       FIG. 3  is a cross sectioned perspective view showing the state where the male terminal of  FIG. 1  is inserted into the female terminal; 
       FIGS. 4A and 4B  are diagrams showing cross sections of the male terminals, wherein  FIG. 4A  is a cross sectional view of the male terminals disposed in parallel, and  FIG. 4B  is a cross sectional view of flat-plate shape male terminals disposed in parallel; 
       FIG. 5  is a perspective view of a female terminal in the preferred embodiment according to the invention; 
       FIG. 6  is a cross sectioned perspective view of the female terminal of  FIG. 5  taken along a longitudinal direction; 
       FIG. 7  is a perspective view of the female terminal of  FIG. 5  viewed from an upper side; 
       FIG. 8  is a perspective view of the female terminal of  FIG. 5  taken along a widthwise direction; 
       FIG. 9  is a graph showing stress relaxing characteristics of an oxygen-free copper and a SUS; 
       FIG. 10  is a cross sectioned perspective view of the connector in a state where the male terminal of  FIG. 1  is inserted into the female terminal of  FIG. 5 ; 
       FIG. 11  is a perspective view of a conventional male terminal; 
       FIG. 12  is a perspective view of a conventional female terminal; and 
       FIG. 13  is a cross sectioned perspective view of a conventional connector in a state where the male terminal of  FIG. 11  is inserted into the female terminal of  FIG. 12 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Next, a connector structure having a male terminal and a female terminal in the preferred embodiment according to the invention will be explained in more detailed in conjunction with the appended drawings. 
     FIG. 1  is a perspective view showing a male terminal of a connector in the preferred embodiment according to the invention. 
     FIG. 2  is a perspective view showing a connector  1  in which the male terminal  10  in the preferred embodiment is inserted into a female terminal  30 . 
   In the preferred embodiment of the present invention, as shown in  FIG. 1 , a male terminal  10  composed of a narrow plate member comprises a wire connecting portion  11  at one end thereof (indicated by an arrow B), to be connected to an electric wire (of the other electrical apparatus), and an inserting contact portion  12  at another end thereof (indicated by an arrow A), to be inserted into the female terminal  30  shown in  FIG. 2 . In the preferred embodiment of the present invention, the inserting contact portion  12  of the male terminal  10  is formed of a flat-plate member and bent to have a U-shape cross section (namely, Japanese character “ ” shape) taken along a widthwise direction. 
   The wire connecting portion  11  and the inserting contact portion  12  are formed of a single plate member, and the wire connecting portion  11  is formed to have a flat-plate shape. The wire connecting portion  11  is provided with a device connecting hole  13  for electrically connecting the male terminal  10  to the other apparatus such as an inverter as well as for fastening and tightening the male terminal  10  with a bolt to the other apparatus. The inserting contact portion (U-shape portion)  12  formed at another end of the single plate comprises a bottom plate  14  to have a flat-plate shape similarly to the wire connecting portion  11 , and projecting pieces  15 ,  15 . Both of the projecting pieces  15 ,  15  are formed by bending both sides of the bottom plate  14  to be substantially perpendicular to the bottom plate  14 . 
   An inserting end portion  16  of the inserting contact portion  12  is formed to have a tapered shape which is narrowed to its end. In concrete, a tip end of the bottom plate  14  and the both of projecting pieces  15 ,  15  are formed to have a tapered shape in a plate thickness direction. By forming the tip end of the inserting end portion  16  to be tapered, an inserting force of the male terminal  10  into the female terminal  30  can be reduced compared with the inserting force of the male terminal  50  into the female terminal  60  shown in  FIG. 12 . 
   In the inserting contact portion (U-shape portion)  12 , it is preferable that a width of the bottom plate  14  is substantially same as a width of an inner frame of the female terminal  30 , and that a height of both of the projecting pieces  15 ,  15  is substantially same as a height of the inner frame of the female terminal  30 . By forming the width of the bottom plate  14  and the height of the projecting pieces  15 ,  15  substantially equal to the width and the height of the inner frame of the female terminal  30 , respectively, looseness within the female terminal  30  can reduced, thereby fixing the male terminal  10  securely to the female terminal  30 . 
   Stopper pieces  17 ,  17  to be engaged with a housing of a connector  1  for accommodating the male terminal  10  are formed to be projected from a back end of the projecting pieces  15 ,  15 , i.e. at a wire connecting portion side of the inserting contact portion  12 . 
     FIGS. 2 and 3  are diagrams showing the state where the male terminal  10  in the preferred embodiment is inserted into the female terminal  30 . 
   In  FIGS. 2 and 3 , the connector  1  comprises the male terminal  10  and the female terminal  30 . The male terminal  10  comprises the wire connecting portion  11 , the inserting contact portion  12 , the device connecting hole  13 , the bottom plate  14 , the projecting piece  15 , and the stopper piece  17 , as described above. The female terminal  30  comprises a terminal energizing portion  31 , a spring  33 , and a wire clamping portion  39 , and the configuration of the female terminal  30  will be explained later in conjunction with  FIGS. 5 to 8 . 
   As shown in  FIGS. 2 and 3 , the male terminal  10  is inserted into the terminal energizing portion  31  of the female terminal  30  such that the stopper piece  17  is located at a lower side of the male terminal  10 , so that the bottom plate  14  is pinched and fixed by the terminal energizing portion  31  pressed by the spring  33 . 
   According to the male terminal structure in this preferred embodiment, a cross section of the inserting contact portion  12  of the male terminal  10  is formed to have a U-shape, so that a cross sectional area and a surface area of the male terminal  10  can be increased compared with the flat-plate shape male terminal having the same width and thickness (plate thickness) as those of the male terminal  10 . Accordingly, by increasing the cross sectional area of the male terminal  10 , a resistance of the male terminal  10  can be reduced so that a heat generation during the current flow can be reduced. Further, by increasing the surface area of the male terminal  10 , the heat dissipation property of the heat generated during the current flow can be enhanced. Accordingly, even though the large current is flown through the male terminal  10 , a heat elevation of the male terminal  10  can be reduced, so that it is possible to suppress the damages of the housing resin of the connector  1  provided with the male terminal  10  and the influences on the peripheral devices of the male terminal  10 . 
   The male terminal  10  is used, for example, for the connection between the motor of the HEV and the inverter, and the wire connecting portion  11  of the male terminal  10  is connected to an inverter side. At this time, as shown in  FIG. 4A , since a three phase current is flown between the inverter and the motor, three terminals are disposed in parallel. In this preferred embodiment, since the inserting contact portion  12  of the male terminal  10  has the U-shape cross section, a distance (d) in a terminal width direction can be shortened, compared with a distance (f) in a terminal width direction of three male terminals  50  disposed in parallel shown in  FIG. 4B , i.e. d&lt;f. Herein, each of the male terminals  50  having a flat-plate cross section has a thickness (t) which is same as a thickness of the male terminal  10 . It is because that a terminal width (b) of the male terminal  10  is shorter than a terminal width (e) of the male terminal  50  having a flat plate shape and the same cross sectional area as that of the male terminal  10 , i.e. b&lt;e. When the three male terminals  10  are disposed in parallel, a sum of the terminal width (b) of the male terminals  10  and a distance (c) between the male terminals  10  is reduced, compared with the case where three flat-plate shaped male terminals  50  are disposed in parallel. Accordingly, by decreasing the terminal width (b), the large current connector comprising the three male terminals  10  disposed in parallel can be miniaturized. 
   If the flat-plate shaped male terminal  50  is formed to have a terminal width equal to that of the male terminal  10  and a terminal thickness greater than that of the male terminal  10 , a cross sectional area of the flat-plate shaped male terminal  50  may be equal to that of the male terminal  10 . However, in this case, the thickness of the flat-plate shaped male terminal  50  is significantly increased. In typical male terminals, a terminal surface is generally coated by a plating to prevent generation of an oxide film on the terminal surface to obtain a stable electrical contact. However, it is difficult to coat the male terminal composed of a thick plate member with the plating. For example, if the flat-plate shaped male terminal  50  is formed to have a width of 13 mm and a cross sectional area of 31.2 mm 2  that are equal to those of the male terminal  10 , a thickness of the male terminal (plate member)  50  will be 2.4 mm. According to the current technology, it is significantly difficult to provide the plate member of 2.4 mm with the plating. The male terminal  10  according to this preferred embodiment is formed to have a narrow width by using a thin plate member, so that it is possible to provide the male terminal  10  with the plating for preventing the generation of the oxide film. 
   Further, in the male terminal  10 , since the wire contacting portion  13  is formed to have a flat-plate shape, the bending process can be easily conducted for the wire contacting portion  13 . For example, even if the male terminal  10  is formed to have the L-shape in accordance with a position of the device to be connected to the male terminal  10 , the wire contacting portion  13  can be easily applied thereto. 
   Next, the female terminal  30  to which the male terminal  10  in this preferred embodiment is inserted will be explained in more detail. 
   As shown in  FIGS. 5 to 8 , the female terminal  30  comprises the terminal energizing portion  31  composed of a high conductivity material having a frame structure, for accommodating the male terminal  10 , i.e. into which the male terminal  10  is inserted, and the spring  33  located within the terminal energizing portion  31  for fixing the male terminal  10  to be inserted. The female terminal  30  further comprises a terminal box  32  composed of a material having strength higher than that of the high conductivity material of the terminal energizing portion  31 , for covering the terminal energizing portion  31 , and the spring  33  is formed integrally with the terminal box  32 . 
   The terminal energizing portion  31  is formed to have a substantially rectangular cross section, and the terminal box  32  is also formed to have a substantially rectangular cross section, such that the terminal box  32  fits with the terminal energizing portion  31 . A part of a surface  34  (an upper surface in  FIGS. 5 to 8 ) of the terminal box  32  is formed to extend from a male terminal insertion side to an inside of the terminal energizing portion  31 , and a part of an extended portion of the terminal box  32  is bent into the terminal energizing portion  31 , so that the spring  33  is formed to be a plate spring. The spring  33  is construed to contact with a convex portion  35  that is formed at a bottom surface (a lower surface in  FIGS. 5 to 8 ) of the terminal energizing portion  31 , and the male terminal  10  inserted from the male terminal insertion side is pinched by the spring  33  and the convex portion  35 , so that the male terminal  10  is fixed in the terminal energizing portion  31 . 
   An opening  36  is formed at the upper surface  34  of the terminal box  32 . The opening  36  is provided with fixing tabs  37 ,  37  for fixing the terminal energizing portion  31 . On the other hand, a surface (an upper surface in  FIGS. 5 to 8 ) of the terminal energizing portion  31  is provided with engaging concave portions  38 ,  38  for engaging with the fixing tabs  37 ,  37 , respectively. The upper surface of the terminal energizing portion  31  contacts with the upper surface  34  of the terminal box  32  on which the opening  36  is provided. In the female terminal  30 , the fixing tab  37  engages with the engaging concave portion  38  by bending the fixing tab  37  into the engaging concave portion  38  to a terminal energizing portion side, namely, to an inside of the female terminal  30 , so that the terminal box  32  and the terminal energizing portion  31  are fixed with each other. 
   According to this structure, the terminal energizing portion  31  and the terminal box  32 , that are composed of different metal plate members, are always fixed at a constant position, so that it is possible to construe the female terminal  30  in which the terminal energizing portion  31  does not fall out from the terminal box  32  and is stably fixed to the terminal box  32 . 
   The terminal energizing portion  31  is formed by bending a plate member composed of a high conductivity material, and formed integrally with the wire clamping portion  39 . The wiring clamping portion  39  is composed of a high conductivity material for fixing the electric wire to the female terminal  30  by clamping the electric wire. 
   The terminal box  32  is formed by bending a single plate member to have a substantially rectangular cross section, a joint  42  is located on a surface (a lower surface in  FIGS. 5 to 8 )  41  opposed to the upper surface  34  on which the opening  36  is formed. The terminal energizing portion  31  is formed by bending a single plate member to have a substantially rectangular cross section, a joint  43  of the terminal energizing portion  31  is located on a surface (an upper surface in  FIGS. 5 to 8 ) opposed to a surface  41  on which the joint  43  of the terminal box  32  is located. 
   The joint  43  of the terminal energizing portion  31  and the joint  42  of the terminal box  32  are positioned to be facing to each other, and the terminal energizing portion  31  is fitted and fixed into the terminal box  32 , so that the terminal energizing portion  31  is strong against a wrenching force applied from inside of the terminal energizing portion  31  when the male terminal  10  is inserted into the terminal energizing portion  31 . 
   Since the conventional female terminal  60  consists of the terminal energizing portion  61  composed of a single plate member, in a case where the terminal energizing portion  61  has a joint, the terminal energizing portion  61  is deformed from the joint when the wrenching force is applied to the terminal energizing portion  61  due to the insertion of the male terminal into the terminal energizing portion  61 . Namely, due to the wrenching force applied to the terminal energizing portion  61 , the plate members are separated from each other at the joint, so that the frame structure cannot be maintained. Therefore, according to the female terminal structure in this preferred embodiment, the frame structure can be maintained by locating the joints at the opposed surfaces. 
   As the high conductivity material composing the terminal energizing portion  31  and the wire clamping portion  39 , it is preferable to use a material with a conductivity of 60% IACS or more, and more preferably a material with a conductivity of 93% IACS or more. 
   In this preferred embodiment, as the high conductivity material, oxygen-free copper with a conductivity of 97% IACS is used. The terminal box  32  is formed by using SUS which is excellent in stress relaxing characteristic. 
   Next,  FIG. 9  is a graph showing respective stress relaxing characteristics of oxygen-free copper and SUS. The respective stress relaxing characteristics shown in  FIG. 9  are stress relaxation rates varied by a heating temperature of a SUS plate member and an oxygen-free copper plate member, that are measured by exposing the SUS plate member and the oxygen-free copper plate member in an environment heated at a temperature of 150° C. 
   As shown in  FIG. 9 , a characteristic line  71  of the oxygen-free copper indicates that the stress relaxation rate of the oxygen-free copper is immediately elevated when the oxygen-free copper is kept at the temperature of 150° C., while a characteristic line  72  of the SUS indicates that the stress relaxation rate of the SUS does not substantially change even though the SUS is kept at the temperature of 150° C. Accordingly, it is understood from the graph of  FIG. 9  that a shape of the terminal box  32  made of SUS hardly changes at the high temperature (150° C.). 
   According to the female structure in this preferred embodiment, the terminal box  32  composed of SUS material with a small stress relaxing characteristic is provided, so as to cover the terminal energizing portion  31  composed of the high conductivity material. A portion of the terminal box  32  bent with an angle of 90° is not opened further, so that the terminal box  32  can keep its shape with the substantially rectangular cross section without deforming even though the female terminal  30  is exposed in the environment of the high temperature. Accordingly, the spring  33  integrally formed with the terminal box  32  is not shifted from the terminal energizing portion  31 , namely a force of pressing the terminal energizing portion  31  is not reduced, so that a contacting force of the male terminal  10  given by the spring  33  can be kept. 
   In other words, the female terminal  30  in this preferred embodiment has the terminal energizing portion  31  composed of the high conductivity material, thereby reducing the heat generated by the large current flow. In addition, the terminal energizing portion  31  is covered with the terminal box  32 , and the spring  33  is formed integrally with the terminal box  32 , thereby keeping a stable large current flow. 
   Further, since it is not necessary to design the connector structure with considering a deterioration in elasticity of the spring  33  at the high temperature, the contacting force can be decreased, so that the force required to insert the male terminal  10  into the female terminal  60  (terminal insertion force) can be reduced. 
     FIG. 10  is a cross sectioned perspective view of the connector  1  in a state where the male terminal  10  of  FIG. 1  is inserted into the female terminal  30  of  FIG. 5 . As shown in  FIG. 10 , the inserting contact portion  12  of the male terminal  10  is inserted into the terminal energizing portion  31  of the female terminal  30 , and the inserting contact portion  12  is fixed by the spring  33  to a bottom surface  44  of the terminal energizing portion  31 . In more concrete, a bottom plate  14  is fixed by the spring  33  of the female terminal  30 . The male terminal  10  is accommodated in the housing of the connector  1  and the stopper piece  17  is engaged with and fixed to the connector housing (not shown). 
   According to the terminal connector structure in which the male terminal  10  is inserted into the female terminal  30  in this preferred embodiment, the heat dissipation property is enhanced and the contacting force between the terminals can be kept even in the environment with the high temperature, so that the stable electrical connection can be realized. 
   Although the invention has been described with respect to the specific embodiments for complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art which fairly fall within the basic teaching herein set forth.