Patent Publication Number: US-10312621-B2

Title: Terminal connection structure

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2017-140600 filed in Japan on Jul. 20, 2017. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a terminal connection structure. 
     2. Description of the Related Art 
     Conventionally, a terminal connection structure that physically and electrically connects male and female terminal metal fittings has been known. When the male terminal metal fitting is inserted into a housing completion position in the female terminal metal fitting, the terminal connection structure described here mutually connects the two. The terminal connection structure is disclosed, for example, in Japanese Patent Application Laid-Open No. 2011-108595. 
     Incidentally, a function of physically and electrically connecting male and female terminal metal fittings and a function of generating holding force between the connected male and female terminal metal fittings are required for a terminal connection structure of this kind. However, a conventional terminal connection structure has a paradoxical relationship in which insertion force between male and female terminal metal fittings is increased when holding force is increased and the holding force is decreased when the insertion force is decreased. 
     SUMMARY OF THE INVENTION 
     The present invention is to provide a terminal connection structure that can secure holding force while keeping insertion force low. 
     A terminal connection structure according to one aspect of the present invention includes a male terminal metal fitting including a columnar or cylindrical male connector; a female terminal metal fitting including a female connector in which a columnar internal space into which the male connector is inserted in an axial direction is provided, and an electric wire connector to which a conductive portion of an electric wire is electrically connected; and a holding structure that is interposed between the male connector, housing of which into the internal space is completed, and the female terminal metal fitting and that generates holding force between the male connector and the female terminal metal fitting, wherein the holding structure includes two first holding bodies that are arranged between the male connector and the female connector in one region of the internal space comparted into two regions in a cylinder axis direction of the female connector and that become contact points between the male connector and the female connector, two second holding bodies that are arranged between the male connector and the female connector in the other region of the comparted internal space and that become contact points between the male connector and the female connector, and a third holding body that is arranged on an opposite side of the first holding bodies in the cylinder axis direction with respect to the second holding bodies and that becomes a contact point between the male connector and the female terminal metal fitting, the first holding bodies are respectively arranged, on a side of one opening of the female connector, in regions formed by further dividing the one region of the internal space into two, the second holding bodies are respectively arranged, on a side of the other opening of the female connector, in regions formed by further dividing the other region of the internal space into two, and the third holding body is arranged in such a manner as to be placed between the first holding bodies when seen in the cylinder axis direction. 
     According to another aspect of the present invention, in the terminal connection structure, it is preferable that the first holding bodies are protruded from an inner peripheral surface of the female connector on the side of the one opening to be an insertion opening for the male connector, the second holding bodies are protruded from the inner peripheral surface of the female connector, and the third holding body is protruded from the female terminal metal fitting at a position closer to a side of the electric wire connector than the first holding bodies and the second holding bodies. 
     According to still another aspect of the present invention, in the terminal connection structure, it is preferable that each of the first holding bodies and the second holding bodies has a convex curve surface to be a contact point. 
     The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a terminal connection structure of an embodiment and illustrating a state before a male terminal metal fitting and a female terminal metal fitting are connected; 
         FIG. 2  is a perspective view illustrating the terminal connection structure of the embodiment and illustrating a state after the male terminal metal fitting and the female terminal metal fitting are connected; 
         FIG. 3  is a front view of the female terminal metal fitting; 
         FIG. 4  is an X1-X1 sectional view of  FIG. 3 ; 
         FIG. 5  is an X2-X2 sectional view of  FIG. 3 ; 
         FIG. 6  is a sectional view illustrating an example of a state in which housing of a male connector into a female connector is completed; 
         FIG. 7  is a sectional view illustrating an example of a state in which housing of the male connector into the female connector is completed; and 
         FIG. 8  is a sectional view illustrating an example of a state in which housing of the male connector into the female connector is completed. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following, an embodiment of a terminal connection structure according to the present invention will be described in detail on the basis of the drawings. Note that this invention is not limited to this embodiment. 
     Embodiment 
     One of embodiments of a terminal connection structure according to the present invention will be described on the basis of  FIG. 1  to  FIG. 8 . 
     A sign  1  in  FIG. 1  to  FIG. 5  indicates a terminal connection structure of the present embodiment. This terminal connection structure  1  relates to connection between a male terminal metal fitting  10  and a female terminal metal fitting  20  in the following. This terminal connection structure  1  includes a holding structure  30  that generates holding force between the male terminal metal fitting  10  and the female terminal metal fitting  20 . 
     The male terminal metal fitting  10  includes a conductive material such as metal. For example, this male terminal metal fitting  10  is formed by press working such as cutting or bending with a conductive metallic plate as a base material. The male terminal metal fitting  10  may be formed by a method other than the press working such as by cutting. This male terminal metal fitting  10  includes a male connector  11 , an electric wire connector  12 , and a coupler  13  ( FIG. 1  and  FIG. 2 ). 
     The male connector  11  is formed in a columnar or cylindrical shape. In the male terminal metal fitting  10 , an axial direction of this male connector  11  is an insertion/removal direction with respect to the female terminal metal fitting  20 . 
     The electric wire connector  12  is a portion to which a conductive portion of an electric wire (not illustrated) is electrically connected. The connection can be anything such as that by crimping such as swaging, that by welding, or that by soldering. In this example, a U-shaped electric wire connector  12  is formed by bending of a plate-shaped base material. The electric wire connector  12  includes two barrel pieces  12   a  facing each other. Each of the barrel pieces  12   a  is wound around a core wire of an electric wire as a conductive portion and is crimped to the conductive portion, whereby physical and electrical connection to this conductive portion is made. 
     The coupler  13  is a portion interposed between the male connector  11  and the electric wire connector  12  and connects these. 
     The female terminal metal fitting  20  includes a conductive material such as metal. For example, this female terminal metal fitting  20  is formed by press working such as cutting or bending with a conductive metallic plate as a base material. The female terminal metal fitting  20  may be formed by a method other than the press working such as by cutting. This female terminal metal fitting  20  includes a female connector  21 , an electric wire connector  22 , and a coupler  23  ( FIG. 1  and  FIG. 2 ). 
     An outer shape of the female connector  21  is not limited but is formed cylindrically according to the columnar or cylindrical male connector  11 . Both ends in a cylinder axis direction of the female connector  21  are opened. An opening at one end (hereinafter, referred to as “first opening”)  21   a  is used as an insertion opening for the male connector  11  (male terminal insertion opening) and is also used as a removal opening of when the male connector  11  is removed (male terminal removal opening). In this example, the male connector  11  inserted from the first opening  21   a  is protruded from an opening at the other end (hereinafter, referred to as “second opening”)  21   b . This female connector  21  includes a columnar internal space  21   c  in which the male connector  11  is inserted and housed in the axial direction. 
     The electric wire connector  22  is a portion to which a conductive portion of an electric wire (not illustrated) is electrically connected. The connection can be anything such as that by crimping such as swaging, that by welding, or that by soldering. In this example, a U-shaped electric wire connector  22  is formed by bending of a plate-shaped base material. The electric wire connector  22  includes two barrel pieces  22   a  facing each other. Each of the barrel pieces  22   a  is wound around a core wire of an electric wire as a conductive portion and is crimped to the conductive portion, whereby physical and electrical connection to this conductive portion is made. 
     The coupler  23  is a portion interposed between the female connector  21  and the electric wire connector  22  and connects these. 
     The holding structure  30  is interposed between the male connector  11 , which is housed in the internal space  21   c , and the female terminal metal fitting  20  and is configured to generate holding force between the male connector  11  and the female terminal metal fitting  20 . Also, this holding structure  30  electrically connects the male connector  11  and the female terminal metal fitting  20 . 
     This holding structure  30  includes two first holding bodies  31 , two second holding bodies  32 , and one third holding body  33  ( FIG. 3  to  FIG. 5 ). The first holding bodies  31 , the second holding bodies  32 , and the third holding body  33  may be provided in the male connector  11  or the female terminal metal fitting  20 . Here, a case where these are provided in the female terminal metal fitting  20  will be described as an example. 
     The first holding bodies  31  are arranged between the male connector  11  and the female connector  21  in one region of the internal space  21   c  comparted into two regions A 1  and A 2  ( FIG. 3 ) in the cylinder axis direction of the female connector  21 . Each of these first holding bodies  31  creates a holding state between the male connector  11  and the female connector  21 , and becomes a contact point between the male connector  11  and the female connector  21 . Here, the first holding bodies  31  are arranged in the region A 1 . More specifically, the first holding bodies  31  are respectively arranged in regions A 1   a  and A 1   b  that are formed by further dividing the region A 1  into two. Also, the first holding bodies  31  are arranged on a side of one opening of the female connector  21 . Here, the first holding bodies  31  are arranged on a side of the first opening  21   a  to be an insertion opening for the male connector  11 . 
     The first holding bodies  31  of this example are protruded from an inner peripheral surface  21   d  of the female connector  21  on a side of the first opening  21   a  in the region A 1 . Each of these first holding bodies  31  is formed as an expanded body expanded from the inner peripheral surface  21   d  and has a convex curve surface to be a contact point with respect to the male connector  11 . Here, a spherical expanded body is used as each of the first holding bodies  31 . Note that a shape of each of the first holding bodies  31  is not necessarily a convex curve surface, and may have a shape other than the convex curve surface as long as a function thereof can be performed. 
     The second holding bodies  32  are arranged between the male connector  11  and the female connector  21  in the other region of the comparted internal space  21   c . Similarly to the first holding bodies  31 , each of these second holding bodies  32  creates a holding state between the male connector  11  and the female connector  21 , and becomes a contact point between the male connector  11  and the female connector  21 . Here, the second holding bodies  32  are arranged in the region A 2 . More specifically, the second holding bodies  32  are respectively arranged in regions A 2   a  and A 2   b  that are formed by further dividing the region A 2  into two ( FIG. 3 ). Also, the second holding bodies  32  are arranged on a side of the other opening of the female connector  21 . Here, the second holding bodies  32  are arranged on a side of the second opening  21   b.    
     The second holding bodies  32  of this example are protruded from the inner peripheral surface  21   d  of the female connector  21  on a side of the second opening  21   b  in the region A 2 . Similarly to the first holding bodies  31 , each of these second holding bodies  32  is formed as an expanded body expanded from the inner peripheral surface  21   d  and has a convex curve surface to be a contact point with respect to the male connector  11 . Here, a spherical expanded body is used as each of the second holding bodies  32 . 
     The third holding body  33  is arranged on an opposite side of the first holding bodies  31  in the cylinder axis direction of the female connector  21  with respect to the second holding bodies  32 . The third holding body  33  of this example is arranged closer to a side of the electric wire connector  22  than the first holding bodies  31  and the second holding bodies  32 . Moreover, this third holding body  33  is arranged in such a manner as to be placed between the first holding bodies  31  when seen in the cylinder axis direction of the female connector  21 . This third holding body  33  creates a holding state between the male connector  11  and the female terminal metal fitting  20 , and becomes a contact point between the male connector  11  and the female terminal metal fitting  20 . 
     The third holding body  33  of this example is protruded from the female terminal metal fitting  20  at a position closer to the side of the electric wire connector  22  than the first holding bodies  31  and the second holding bodies  32 . Here, the third holding body  33  is provided from a side of the second opening  21   b  on the inner peripheral surface  21   d  of the female connector  21  to the coupler  23 . Similarly to the first holding bodies  31  or the second holding bodies  32 , this third holding body  33  may be formed as an expanded body expanded toward the male connector  11 . In this case, the third holding body  33  has a convex curve surface to be a contact point with respect to the male connector  11 , and a spherical expanded body can be used as the third holding body  33 . Also, the third holding body  33  may be a cantilever piece that is formed in press forming of the female terminal metal fitting  20  and that is bent from a side of a base. In this example, a third holding body  33  in a shape of the piece is provided. This third holding body  33  in the shape of the piece has elasticity with the base thereof as an origin, and can apply pressing force associated with reaction force thereof to the male connector  11  when being elastically deformed by the male connector  11 . That is, this third holding body  33  in the shape of the piece contributes to improvement of holding force between the male connector  11  and the female terminal metal fitting  20 . 
     In this terminal connection structure  1 , when insertion of a leading end of the male connector  11  from the first opening  21   a  into the internal space  21   c  of the female connector  21  is started, the male connector  11  comes into contact with the two first holding bodies  31  and is supported thereby. This state is kept until the male connector  11  comes into contact with the two second holding bodies  32 . Thus, frictional resistance applied to the male connector  11  is generated between this and the two first holding bodies  31  until the male connector  11  comes into contact with the two second holding bodies  32 . Thus, in this terminal connection structure  1 , the male connector  11  can be inserted into the female connector  21  with low insertion force since the frictional resistance is low until the male connector  11  comes into contact with the two second holding bodies  32 . Specifically, in this example, since the convex curve surfaces of the first holding bodies  31  are in contact with the male connector  11 , the frictional resistance can be further decreased and the male connector  11  can be inserted into the female connector  21  with lower insertion force. 
     In this terminal connection structure  1 , the male connector  11  comes into contact with the two second holding bodies  32  in a final stage of the process of inserting the male connector  11  into the female connector  21 , and the male connector  11  comes into contact with the third holding body  33  in an appropriate period ( FIG. 6 ). That is, in this terminal connection structure  1 , the frictional resistance applied to the male connector  11  becomes high in the final stage of the process of inserting the male connector  11  into the female connector  21 . Thus, operation of inserting the male connector  11  with low insertion force can be performed in this terminal connection structure  1 . On the other hand, in this terminal connection structure  1 , when housing of the male connector  11  into the female connector  21  is completed, the male connector  11  is in contact with the two first holding bodies  31 , the two second holding bodies  32 , and the one third holding body  33  and is supported thereby. Thus, in this terminal connection structure  1 , the holding force between the male connector  11  and the female terminal metal fitting  20  is increased when housing of the male connector  11  into the female connector  21  is completed. Moreover, in the terminal connection structure  1  of this example, since reaction force (pressing force) is applied from the elastically-deformed third holding body  33  to the male connector  11 , higher holding force can be generated. 
     Note that the male connector  11  is supported by the two first holding bodies  31  and is inclined until coming into contact with the two second holding bodies  32 . Thus, there is a possibility that a leading end also comes into contact with the inner peripheral surface  21   d  of the female connector  21  or a side of the first opening  21   a  also comes into contact with a periphery or the like of the internal space  21   c . However, in this terminal connection structure  1 , an increase in the frictional resistance due to an increase in contact parts of the male connector  11  is insignificant. It is possible to insert the male connector  11  into the female connector  21  with low insertion force until the male connector  11  comes into contact with the two second holding bodies  32 . 
       FIG. 7  is a view illustrating a housing completion state of the male connector  11  in a case where the leading end is inclined toward the inner peripheral surface  21   d  on a side of the region A 1 . In this case, for example, the male connector  11  slid on the inner peripheral surface  21   d  pushes the third holding body  33  and elastically deforms this third holding body  33 , whereby reaction force (pressing force) is applied from the third holding body  33  to the male connector  11 . Thus, in this case, although an insertion amount of the male connector  11  is smaller than that of the example in  FIG. 6 , the male connector  11  is held by the two first holding bodies  31 , the two second holding bodies  32 , and the one third holding body  33 . 
     Also,  FIG. 8  is a view illustrating a housing completion state of the male connector  11  in a case where the leading end is inclined toward the inner peripheral surface  21   d  on a side of the region A 2  or a case where the male connector  11  is further pushed from the housing completion position in  FIG. 6 . In these cases, for example, the male connector  11  pushes and elastically deforms the third holding body  33 , whereby reaction force (pressing force) is applied from the third holding body  33  to the male connector  11 . Thus, in these cases, although an insertion amount of the male connector  11  is larger than that of the example in  FIG. 6 , the male connector  11  is held by the two first holding bodies  31 , the two second holding bodies  32 , and the one third holding body  33 . However, in these cases, the male connector  11  is in an inclined state due to the reaction force from the third holding body  33 . 
     As described above, while keeping insertion force of when the male connector  11  is inserted into the female connector  21  low, the terminal connection structure  1  of the present embodiment can secure holding force between the male connector  11  and the female terminal metal fitting  20  of when housing of the male connector  11  into the female connector  21  is completed. 
     Here, in a case where a holding structure  30  is provided in a male connector  11 , two first holding bodies  31 , two second holding bodies  32 , and one third holding body  33  are serially arranged from a side of a leading end of the male connector  11 . In an arrangement of these, the male connector  11  is divided into four regions in an axial direction similarly to the female connector  21 , and the two first holding bodies  31 , the two second holding bodies  32 , and the one third holding body  33  are distributed to these regions similarly to the foregoing example. An effect similar to that of the foregoing example can be acquired even when a terminal connection structure  1  is configured in such a manner. 
     Also, in this terminal connection structure  1 , an elastic member (not illustrated) that applies force in a direction of connection operation between a male connector  11  and a female connector  21  may be provided in at least one of a male terminal metal fitting  10  and a female terminal metal fitting  20 . In this terminal connection structure  1 , with force from the elastic member, insertion force of the male connector  11  can be further decreased and holding force between the male connector  11  and the female terminal metal fitting  20  can be further increased. Also, in this terminal connection structure  1 , a contact load necessary for securing electrical conduction between the male terminal metal fitting  10  and the female terminal metal fitting  20  can be generated in first holding bodies  31 , second holding bodies  32 , and a third holding body  33 . 
     In a terminal connection structure according to the present embodiments, with arrangements of two first holding bodies, two second holding bodies, and a third holding body, it is possible to keep insertion force of when a male connector is inserted into a female connector low and to secure holding force between the male connector and a female terminal metal fitting of when housing of the male connector into the female connector is completed. 
     Although the invention has been described with respect to specific embodiments for a 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 that fairly fall within the basic teaching herein set forth.