Patent Publication Number: US-11381034-B2

Title: Connector fitting body

Description:
BACKGROUND 
     Field of the Invention 
     The present invention relates to a connector fitting body in which a male housing and a female housing respectively holding terminals are fit using a bolt. 
     Related Art 
     A relay connector for relaying electrical wiring is used when connecting various electrical devices and the like to a control device. The relay connector forms a connector fitting body by fitting a male connector including male terminals and a female connector including female terminals to be conductive with the male terminals. A lever-type fitting structure utilizing the principle of leverage, a tightening-type fitting structure utilizing the tightening of a bolt and the like to facilitate fitting by a worker have been proposed as a fitting structure of a male connector and a female connector besides direct fitting by a worker. 
     Japanese Unexamined Patent Publication No. 2011-249050 discloses a connector fitting body having a tightening-type fitting structure where a housing and a mating housing are fit by tightening a bolt inserted through a bolt mounting portion of the housing to a nut provided in the mating housing. 
     In a conventional connector fitting body having a tightening-type fitting structure such as the one of Japanese Unexamined Patent Publication No. 2011-249050, a head of a bolt comes into contact with a bolt mounting portion that is a part of a housing, and the bolt is tightened to a nut to compress the bolt mounting portion between the head and the nut. That is, an axial force generated by tightening the bolt is applied to the nut via the bolt mounting portion made of a resin material for ensuring insulation with terminals. Thus, unless a bolt tightening torque is managed properly, the bolt mounting portion may be damaged. Further, the bolt tightening torque needs to be limited as appropriate in consideration of an axial force applied to the housing made of the resin material. 
     A larger tightening torque is required to tighten the bolt as more male terminals and female terminals are used and/or as the contact strength of the male terminals and the female terminals increases. A large tightening torque increases an axial force applied from the bolt to the housing. 
     Accordingly, to easily manage a bolt tightening torque in forming a tightening-type connector fitting body, a further structural ingenuity is required. 
     The present invention was developed in view of such a problem and is to provide a connector fitting body capable of protecting a first housing and a second housing from damage when a bolt is tightened and easily managing a bolt tightening torque. 
     SUMMARY 
     A first aspect of the invention is directed to a connector fitting body with a first housing holding first terminals and a second housing holding second terminals to be brought into contact and conduction with the first terminals by fitting the second housing to the first housing. A nut is arranged in a nut arrangement hole in the second housing, and a bolt including a head is arranged in a bolt arrangement hole in the first housing. A shaft extends coaxially from the head and can be engaged threadedly with the nut. The head includes a first step for pressing the first housing toward the second housing, and the nut includes a second step for pressing the second housing toward the first housing. An end surface of the head is in contact with an end surface of the nut. 
     A second aspect of the invention is directed to a connector fitting body with a first housing holding first terminals and a second housing holding second terminals to be brought into contact and conduction with the first terminals by fitting the second housing to the first housing. A nut is arranged in a nut arrangement hole provided in the second housing. A bolt includes a head portion and a shaft extending coaxially from the head. The shaft is inserted into a bolt insertion hole provided in the first housing and is engaged threadedly with the nut. A collar made of metal faces the nut and is arranged between an outer periphery of the shaft portion and an inner periphery of the bolt insertion hole. The collar includes a first step for pressing the first housing toward the second housing, and the nut includes a second step for pressing the second housing toward the first housing. An end surface of the collar is in contact with an end surface of the nut. 
     [Effects of Invention] 
     (Connector Fitting Body of the First Aspect) 
     The connector fitting body of the first aspect is a tightening type so that the first and second housings are fit by tightening the bolt to the nut. In this connector fitting body, when the bolt is tightened to the nut, the first step of the head of the bolt presses the first housing toward the second housing and the second step of the nut receives the second housing. In this way, the first housing approaches the second housing. Then, the end surface of the head contacts (is seated on) the end surface of the nut and the bolt is tightened to the nut. 
     At this time, the contact of the end surface of the head of the bolt with the end surface of the nut ensures that an axial force generated when the bolt is tightened does not act as a compression force on the first housing and the second housing. In this way, an excessive compression force does not act on the first and second housings when the bolt is tightened. Thus, the first and second housings can be protected from damage, and a tightening torque of the bolt need not be managed strictly. Further, a large tightening torque can be dealt with. 
     Therefore, the connector fitting body of the first aspect protects the first and second housings from damage when the bolt is tightened and the tightening torque of the bolt can be managed easily. 
     (Connector Fitting Body of the Second Aspect) 
     The connector fitting body of the second aspect is a tightening type so that the first and second housings are fit by tightening the bolt to the nut via the collar. In this connector fitting body, when the bolt is tightened to the nut via the collar, the first step of the collar presses the first housing toward the second housing and the second step of the nut receives the second housing. In this way, the first housing approaches the second housing. Then, the end surface of the collar contacts (is seated on) the end surface of the nut and the bolt is tightened to the nut. 
     At this time, the contact of the end surface of the collar with the end surface of the nut ensures that an axial force generated when the bolt is tightened acts as a compression force on the first and second housings. In this way, functions and effects similar to those of the connector fitting body of the first aspect are obtained also in the connector fitting body of the second aspect. 
     Therefore, the connector fitting body of the second aspect ensures the first and second housings can be protected from damage when the bolt is tightened and the tightening torque of the bolt can be managed easily. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front view in section of a connector fitting body according to a first embodiment. 
         FIG. 2  is a section enlargedly showing a part of  FIG. 1 . 
         FIG. 3  is a view showing a bolt according to the first embodiment. 
         FIG. 4  is a front view in section of a second connector of the connector fitting body of the first embodiment. 
         FIG. 5  is a front view in section of a first connector of the connector fitting body according to the first embodiment. 
         FIG. 6  is a view of the first connector of the connector fitting body according to the first embodiment viewed from an air side. 
         FIG. 7  is a section further enlargedly showing a part of  FIG. 2 . 
         FIG. 8  is a view of the first connector the connector fitting body according to the first embodiment viewed from an oil side. 
         FIG. 9  is a front view in section showing a state where the first and second connectors according to the first embodiment are fit to form the connector fitting body. 
         FIG. 10  is a front view showing the connector fitting body according to the first embodiment. 
         FIG. 11  is a front view in section showing a connector fitting body according to a second embodiment. 
         FIG. 12  is a section enlargedly showing a part of  FIG. 11 . 
         FIG. 13  is a view showing a bolt according to the second embodiment. 
         FIG. 14  is a section showing an oil-proof second sealing member according to the second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Preferred embodiments according to the connector fitting body described above are described with reference to the drawings. 
     First Embodiment 
     A connector fitting body  1  of this embodiment includes, as shown in  FIG. 1 , a first housing  2 , a second housing  3 , a nut  5  and a bolt  4 . First terminals  21  are held in the first housing  2  and second terminals  31  to be brought into contact and conduction with the first terminals  21  are held in the second housing  3 . The nut  5  is arranged in a nut arrangement hole  32  in the second housing  3 . The bolt  4  includes a head  41  arranged in a bolt arrangement hole  22  in the first housing  2  and a shaft  42  extends coaxially from the head  41  and is engaged threadedly with the nut  5 . 
     As shown in  FIG. 2 , the head  41  includes a large-diameter portion  411  serving as a first step for pressing the first housing  2  toward the second housing  3 . The nut  5  includes a general portion  51  serving as a second step for pressing the second housing  3  toward the first housing  2 . An end surface  410  of the head  41  is in contact with an end surface  520  of the nut  5 . 
     The connector fitting body  1  of this embodiment is described in detail below. 
     (Connector Fitting Body  1  and Arrangement Environment Thereof) 
     As shown in  FIG. 1 , the connector fitting body  1  is used as a relay connector for relaying electrical wiring when various electronic control devices  72  are wired electrically to a control device (control board)  8 . A control circuit for controlling the various electronic control devices  72  is formed on the control board  8 . The connector fitting body  1  is formed by fitting a first connector  1 A composed of the first terminals  21  and the first housing  2  and a second connector  1 B composed of the second terminals  31  and the second housing  3 . 
     The electronic control devices  72  can be mounted in various machine components  7 . The machine component  7  of this embodiment is an automatic transmission mounted in an automotive vehicle and the electronic control devices  72  are a spool valve of a valve body, actuators such as a motor, sensors such as a resolver and the like used in the automatic transmission. The electronic control devices  72  are electrically connected to the control board  8  constituting an electronic control unit (ECU) via the plurality of first and second terminals  21 ,  31  of the connector fitting body  1 . Note that the machine component  7  may be any one of various machine components other than the automatic transmission. 
     As shown in  FIG. 1 , oil (automatic transmission oil) is used for an automatic shift control operation, lubrication between constituent components and the like in the automatic transmission. The connector fitting body  1  is arranged in a case hole  711  provided in a case  71  of the automatic transmission. An outer peripheral sealing member  232  for oil to be held in contact with the inner periphery of the case hole  711  is mounted on the outer periphery of the first housing  2  of the connector fitting body  1 . The outer peripheral sealing member  232  is arranged in an outer peripheral groove  231  formed in the outer periphery of the first housing  2 . The outer peripheral sealing member  232  prevents leakage of the oil in the case  71  to the outside of the case  71  through a clearance between the connector fitting body  1  and the case hole  711 . 
     When the connector fitting body  1  is arranged in the case hole  711 , the second terminals  31  held in the second housing  3  are exposed to an oil environment R 2  to be able to contact oil, a part of the first housing  2  projects from the case hole  711  and the first terminals  21  held in the first housing  2  are exposed to an air environment R 1 , i.e. to air. 
     As shown in  FIGS. 1 to 10 , a direction along an axial direction L of the bolt  4  is referred to as an axial direction L in the connector fitting body  1  of this embodiment. Further, a direction along long sides of the connector fitting body  1  in a plane perpendicular to the axial direction L is referred to as a width direction W, and a direction along short sides of the connector fitting body  1  in the plane perpendicular to the axial direction L is referred to as a thickness direction B. Further, in the axial direction L of the connector fitting body  1 , a side where the first connector  1 A is located and that is exposed to the air environment R 1  is referred to as an air side L 1  and a side where the second connector  1 B is located and that is exposed to the oil environment R 2  is referred to as an oil side L 2 . 
     (Bolt  4 ) 
     As shown in  FIGS. 2 and 3 , the bolt  4  is arranged at a center position in the width direction W and the thickness direction B of the connector fitting body  1 . The bolt  4  is a special bolt whose head  41  has a sealing function. The bolt  4  is made of a metal material. The head  41  of the bolt  4  is formed into a stepped shape by the large-diameter portion  411  serving as the first step to press the first housing  2  toward the second housing  3  when an axial force is generated by bolt tightening. 
     The head  41  of this embodiment includes a small-diameter portion  412  formed on an end part on the side of the second housing  3  (oil side L 2 ) and the large-diameter portion  411  serving as the first step, larger in diameter than the small-diameter portion  412  and formed adjacent to the small-diameter portion  412  on the side of the first housing  2  (air side L 1 ). A first projection  221  is formed in the bolt arrangement hole  22  of the first housing  2  and is to be pressed toward the second housing  3  by the large-diameter portion  411 . The first projection  221  is located on an outer peripheral side of the small-diameter portion  412  and projects toward an inner peripheral side of the bolt arrangement hole  22 . The first projection  221  of this embodiment is formed by narrowing a part in the axial direction L of the bolt arrangement hole  22 . 
     The first projection  221  is a part of the first housing  2  for receiving an axial force (thrust force) generated when the bolt  4  is tightened. Further, the first projection  221  is also a part for maintaining a state where the first and second housings  2 ,  3  are fit. 
     As shown in  FIGS. 2 and 3 , a first groove  415  is formed in the outer periphery of the large-diameter portion  411 , and the oil-proof sealing member  43  is mounted in this first groove  415  for sealing the clearance between the large-diameter portion  411  and the bolt arrangement hole  22 . The oil-proof sealing member  43  is an O-ring made of rubber. The oil-proof sealing member  43  may be one of various packings capable of sealing oil beside the O-ring. Note that the oil-proof sealing member  43  may be mounted on the outer periphery of the small-diameter portion  412 . 
     The oil-proof sealing member  43  ensures that oil penetrating into the clearance between the head  41  of the bolt  4  and the bolt arrangement hole  22  through a clearance between the nut  5  and the nut arrangement hole  32  cannot further penetrate to the control board  8 . 
     As shown in  FIGS. 2 and 3 , the large-diameter portion  411  and the small-diameter portion  412  have a circular cross-sectional shapes. A hollow cylindrical portion  413  having a circular cross-sectional shape and coaxially connected to the large-diameter portion  411  is formed on the air side L 1  of the large-diameter portion  411  in the axial direction L. The hollow cylindrical portion  413  is formed on an end of the head  41  on the air side L 1  opposite to the shaft  42 . 
     A tool engaging portion  414  with which a tightening tool is engaged is formed on an end part of the hollow cylindrical portion  413  on the air side L 1 . The tool engaging portion  414  of this embodiment is formed by a hexagonal recess. Further, as shown in  FIGS. 1 and 2 , a second groove portion  416  is formed in the outer periphery of the hollow cylindrical portion  413 , and a waterproof sealing member  44  for sealing a clearance between the head portion  41  and a through hole  821  formed in a cover  82  for covering the control board  8  is mounted in this second groove portion  416 . 
     The waterproof sealing member  44  prevents the entrance of water to the control board  8  through the clearance between the head  41  of the bolt  4  and the through hole  821  even if the cover  82  of the control board  8  is wetted. 
     An external thread  421  is formed on the outer periphery of the shaft  42  of the bolt  4 . The external thread  421  of the shaft  42  of this embodiment is formed up to a boundary position with the head  41 . Note that, although not shown, an escape groove is formed on the shaft  42  at the time of threading and is at the boundary position with the head  41 . 
     (Nut  5 ) 
     As shown in  FIGS. 3 and 4 , the nut  5  is formed with an internal thread (screw hole)  53  to be engaged threadedly with the external thread  421  of the shaft  42  of the bolt  4 . The nut  5  is made of metal and is arranged in the nut arrangement hole  32  of the second housing  3 , thereby being prevented from turning when the bolt  4  is tightened. The nut  5  of this embodiment has a rectangular cross-sectional shape and is prevented from turning with respect to the nut arrangement hole  32 . Note that the nut  5  may have one of various shapes capable of preventing turning with respect to the nut arrangement hole  32 . 
     The nut  5  is formed into a stepped shape by the general portion  51  serving as the second step for pressing the second housing  3  toward the first housing  2  when receiving an axial force due to the tightening of the bolt  4 . The nut  5  of this embodiment also includes a reduced portion  52  smaller than the general portion  51  in the width direction W and the thickness direction B and formed adjacent to the general portion  51  on the side of the first housing  2 . 
     The general portion  51  of this embodiment is formed into a rectangular parallelepiped shape, and the reduced portion  52  is formed into a hollow cylindrical shape. Note that the reduced portion  52  may be smaller than the general portion  51  in at least one of the width direction W and the thickness direction B. As shown in  FIG. 2 , a second projection  321  is formed in the nut arrangement hole  32  of the second housing  3  and is to be pressed toward the first housing  2  by the general portion  51 . The second projection  321  is on an outer peripheral side of the reduced portion  52  and projects toward an inner peripheral side of the nut arrangement hole  32 . 
     The second projection  321  is a part of the second housing  3  for receiving an axial force (thrust force) generated when the bolt  4  is tightened. Further, the second projection  321  is a part for maintaining the state where the first and second housings  2 ,  3  are fit. 
     As shown in  FIGS. 2 and 4 , the nut  5  can be arranged in the second housing  3  by insert-molding the second housing  3 . Alternatively, the nut  5  can be arranged in the nut arrangement hole  32  of the second housing  3  after the second housing  3  is molded. The bolt arrangement hole  22  of the first housing  2  and the nut arrangement hole  32  of the second housing  3  communicate with each other in the connector fitting body  1 . 
     (First Terminals  21 ) 
     As shown in  FIG. 1 , the connector fitting body  1  of this embodiment is mounted on a printed board serving as the control board  8 . The first terminals  21  are conductor pins made of a conductive metal and serving as male terminals to be conductive with conductor portions  811  on the control board  8 . The first terminal  21  is inserted through a through hole  81  formed in the control board  8  and electrically connected to the conductor portion  811  of the control board  8  by soldering or the like. 
     As shown in  FIG. 5 , intermediate parts  211  of the first terminals  21  are embedded in a facing plate  23  of the first housing  2  facing the second housing  3 . Both end parts  212 ,  213  of the first terminals  21  project toward opposite sides in the axial direction L from the facing plate  23 . The first end parts  212  of the first terminal  21  on the air side L 1  are connected to the control board  8 . The second end parts  213  of the first terminals  21  on the oil side L 2  are connected to the respective second terminals  31 . 
     (Second Terminals  31 ) 
     As shown in  FIG. 1 , wires  311  wired to the electronic control devices  72  in the oil environment R 2  are connected to the second terminals  31 . Each second terminal  31  is made of a conductive material. The plurality of second terminals  31  constitute female terminals and are held in terminal holes  34  formed in the second housing  3 . 
     The first terminals  21  and the second terminals  31  are arranged side by side in the width direction W and the thickness direction B orthogonal to the axial direction L while being parallel to the axial direction L of the bolt  4 . The first terminals  21  are arranged in a divided manner on both sides of the bolt arrangement hole  22  in the width direction W, and the second terminals  31  are arranged in a divided manner on both sides of the nut arrangement hole  32  in the width direction W. 
     (First Housing  2 ) 
     As shown in  FIGS. 5 and 6 , the first housing  2  forms the first connector  1 A serving as a male connector and is formed by insert-molding a resin material, such as a thermoplastic resin, with the first terminals  21  inserted. The first housing  2  includes the facing plate  23  facing the second housing  3 , arrangement recesses  24  formed on the air side L 1  of the facing plate  23  to arrange the first end parts  212  of the first terminals  21 , a head recess  25  formed on the air side L 1  of the facing plate  23  to arrange the head  41  of the bolt  4 , and fitting recesses  26  formed on the oil side L 2  of the facing plate  23 , with the second connector  1 B (second housing  3 ) being fit into the fitting recesses  26 . 
     The bolt arrangement hole  22  penetrates through the facing plate  23  in the axial direction L at the center position of the first housing  2  in the width direction W and the thickness direction B. The first projection  221  projects toward the inner peripheral side over the entire inner periphery of the bolt arrangement hole  22 . As shown in  FIGS. 2 and 5 , by forming the first projection  221 , the bolt arrangement hole  22  is divided into a large-diameter hole portion  222  in which the large-diameter portion  411  of the head  41  of the bolt  4  is arranged and a small-diameter hole portion  223  that is adjacent to the large-diameter hole portion  222  on the oil side L 2  and in which the small-diameter portion  412  of the head  41  of the bolt  4  is arranged. 
     As shown in  FIG. 2 , a step surface  224  formed by an end surface of the first projection  221  is formed between the large-diameter hole portion  222  and the small-diameter hole portion  223 . When the bolt  4  is turned about a center axis thereof, an end surface  419  of the large-diameter portion  411  comes into contact with the step surface  224  of the first projection  221  and the first housing  2  is slid in the axial direction L. 
     With the first and second connectors  1 A,  1 B fit, the end surface  419  of the large-diameter portion  411  and the step surface  224  of the first projection  221  face each other, as shown in  FIG. 2 , and an end surface  233  on the oil side L 2  of the facing plate  223  of the first housing  2  faces an end surface  301  on the air side L 1  of the second housing  3 , as shown in  FIG. 1 . On the other hand, in this state, a clearance S is formed between an end surface  225  on the oil side L 2  of the first projection  221  and an end surface  322  on the air side L 1  of the second projection  321  as shown in  FIGS. 2 and 7 . 
     By forming this clearance S, the first projection  221  is prevented from being sandwiched between the bolt  4  and the nut  5  when the bolt  4  is tightened to the nut  5 . Thus, an axial force generated by tightening the bolt  4  is less likely to act as a compression force on the first projection  221 . 
     As shown in  FIGS. 5 and 6 , the arrangement recesses  24  are formed on both sides of the head recess  25  in the width direction W. The arrangement recesses  24  are formed by being surrounded by an air-side outer wall  241  projecting toward the air side L 1  from an entire outer peripheral part of the facing plate  23  and partition walls  242  formed in the air-side outer wall  241 . The partition walls  242  are formed on both sides of the head  41  of the bolt  4  in the width direction W, and the head recess  25  is formed between two of the partition walls  242 . 
     A sealing resin portion  243  made of an adhesive, such as a thermosetting resin, is formed on a bottom part of the arrangement recess  24 . The sealing resin portion  243  is formed in contact with the entire periphery of each first terminal  21 . Even if oil penetrates into a clearance between each first terminal  21  and the first housing  2 , the sealing resin portion  243  prevents the penetration of this oil to the control board  8  along each first terminal  21 . 
     As shown in  FIGS. 5 and 8 , the fitting recesses  26  are formed on both sides of the nut arrangement hole  32  in the width direction W. The fitting recesses  26  are formed by being surrounded by an oil-side side wall  261  projecting toward the oil side L 2  from the entire outer peripheral part of the facing plate  23 . Further, two ribs  27  projecting from the facing plate  23  of the first housing  2  toward the oil side L 2  are formed in the fitting recesses  26  on both sides of the bolt arrangement hole  22  in the width direction W. These ribs  27  are utilized to guide a sliding movement of the second housing  3  in the axial direction L with respect to the first housing  2  when the second housing  3  is fit to the first housing  2 . 
     The ribs  27  extend out in the width direction W from positions adjacent to the sides of the bolt arrangement hole  22  in the width direction W. Projecting amounts of the ribs  27  toward the oil side L 2  from the facing plate  23  are larger than those of the second end parts  213  of the first terminals  21  toward the oil side L 2  from the facing plate  23 . In this way, the guiding of the second connector  1 B by the ribs  27  can be started before the second terminals  31  contact the first terminals  21  when the second connector  1 B is fit into the fitting recesses  26  of the first connector  1 A, as shown in  FIG. 9 . 
     Further, as shown in  FIG. 8 , the rib  27  includes a first rib portion  271  extending in the thickness direction B at the position adjacent to one of the sides of the bolt arrangement hole  22  in the width direction W and a second rib portion  272  extending outward in the width direction W from a central part of the first rib portion  271  in the thickness direction B. The rib  27  is in the form of a T-shaped wall by combining the first and second rib portions  271 ,  272 . 
     The first terminals  21  are arranged in the width direction W in each of two rows. The second rib portion  272  is arranged between the two terminal rows to divide the two terminal rows in the thickness direction B. The second rib portion  272  increases a creepage distance for insulation between the first terminals  21  in the respective terminal rows. 
     As shown in  FIGS. 6 and 10 , the first and second housings  2 ,  3  have rectangular outer shapes orthogonal to the axial direction L. The outer peripheral sealing member  232  mounted on the outer periphery of the first housing  2  is made of a rubber material and is formed into a rectangular shape. The rectangular outer peripheral sealing member  232  enables oil to be sealed in a small space of the connector fitting body  1 . 
     (Second Housing  3 ) 
     As shown in  FIGS. 4 and 9 , the second housing  3  forms the second connector  1 B serving as a female connector and is formed by molding a resin material, such as a thermoplastic resin. The second housing  3  is formed with rib holes  33  into which the ribs  27  of the first housing  2  are inserted. Each rib hole  33  is formed in conformity with the entire or partial shape of the rib  27  to guide the rib  27  in the axial direction L. Each rib hole  33  extends from an end part on the air side L 1  toward the oil side L 2 . 
     The connector fitting body  1  is devised to prevent erroneous fitting of the first and second housings  2 ,  3 . Specifically, in the first housing  2 , a length in the thickness direction B of the first rib portion  271  of one rib  27  is longer than that of the first rib portion  271  of the other rib  27 . In the second housing  3 , a length of one rib hole  33  in the thickness direction B matches the length in the thickness direction B of the first rib portion  271  of the one rib  27 . Further, in the second housing  3 , a length of the other rib hole  33  in the thickness direction B matches the length in the thickness direction B of the first rib portion  271  of the other rib  27 . 
     The first and second housings  2 ,  3  can be fit to each other only when the one rib  27  and the one rib hole  33  are aligned and the other rib  27  and the other rib hole  33  are aligned. In this way, the first and second housings  2 ,  3  are prevented from being fit in inverted postures. 
     Further, as shown in  FIG. 1 , a bracket  36  is mounted on the second housing  3  for loosely movably mounting the connector fitting body  1  on the automatic transmission serving as the machine component  7 . The second housing  3  is formed with an engaging portion  35  to be loosely movably engaged with the bracket  36 . The connector fitting body  1  is loosely movably supported on the automatic transmission by the bracket  36 . When the case  71  is mounted on the automatic transmission, the connector fitting body  1  loosely moves with respect to the automatic transmission so that the connector fitting body  1  easily can be arranged in the case hole  711  of the case  71 . 
     (Dimensional Relationship) 
     Further, in the connector fitting body  1  of this embodiment, the following dimensional relationship is managed to make a compression force difficult to act in the axial direction L on the first and second projections  221 ,  321 . 
     Specifically, as shown in  FIG. 7 , a distance L 3  in the axial direction L between the end surface  419  on the oil side L 2  of the large-diameter portion (first step)  411  on the head  41  of the bolt  4  and the end surface  511  on the air side L 1  on the general portion (second step) of the nut  5  is longer than the sum of a thickness T 1  in the axial direction L of the first projection  221  and a thickness T 2  in the axial direction L of the second projection  321 . This dimensional relationship is satisfied by forming the clearance S between the end surface  225  on the oil side L 2  of the first projection  221  and the end surface  322  on the air side L 1  of the second projection  321 . 
     Further, as shown in  FIG. 1 , a tightening force generated between the large-diameter portion  411  on the head  41  of the bolt  4  and the general portion  51  of the nut  5  acts on the first and second housings  2 ,  3  outside a region in the width direction W and the thickness direction B where the first and second projections  221 ,  321  are formed. Specifically, the first and second housings  2 ,  3  are sandwiched between the large-diameter portion  411  on the head  41  of the bolt  4  and the general portion  51  of the nut  5  by facing surfaces of the large-diameter portion  411  and the first projection  221 , facing surfaces of the facing plate  23  of the first housing  2  and the second housing  3  and facing surfaces of the general portion  51  and the second projection  321 . 
     (Assembling/Arranging Method of Connector Fitting Body  1 ) 
     Next, a case where the connector fitting body  1  is used as a relay connector is described. 
     Assembling the connector fitting body  1  involves preparing: the first connector  1 A with the first terminals  21  in the first housing  2 , the second connector  1 B with the second terminals  31  in the second housing  3 , the bolt  4  and the nut  5  having the oil-proof sealing member  43  and the waterproof sealing member  44  mounted thereon, as shown in  FIG. 9 . Further, the wires  311  are connected to the respective second terminals  31  of the second connector  1 B. Then, the bolt  4  is arranged in the bolt arrangement hole  22  of the first connector  1 A, and the nut  5  is arranged in the nut arrangement hole  32  of the second connector  1 B. 
     Subsequently, the first and second connectors  1 A,  1 B are caused to face each other with the first terminals  21  and the second terminals  31  facing each other. Then, as shown in  FIG. 1 , the bolt  4  is turned by the tool engaged with the tool engaging portion  414  of the head  41  to engage the external thread  421  of the shaft  42  of the bolt  4  threadedly with the internal thread  53  of the nut  5 . As the bolt  4  is turned, the large-diameter portion (first step)  411  of the head  41  of the bolt  4  presses the first projection  221  of the first housing  2  toward the second housing  3 . Further, the general portion (second step)  51  of the nut  5  receives the second projection  321  of the second housing  3 . In this way, the first connector  1 A approaches the second connector  1 B, and the first terminals  21  are inserted into the terminal holes  34  having the respective second terminals  31  arranged therein. 
     Subsequently, the bolt  4  is tightened to the nut  5  and the first terminals  21  are connected to the respective second terminals  31 . When the end surface  410  of the small-diameter portion  412  on the head  41  of the bolt  4  comes into contact with the end surface  520  of the nut  5 , the first and second projections  221 ,  321  are not sandwiched between the large-diameter portion  411  of the head  41  and the general portion  51  of the nut  5 . Thus, a tightening force of the bolt  4  is received directly by the nut  5 . In this way, the connector fitting body  1  in which the first and second connectors  1 A,  1 B are fit is formed. 
     Subsequently, as shown in  FIG. 1 , the connector fitting body  1  is mounted on the automatic transmission of the machine component  7  by the bracket  36  mounted on the engaging portion  35  of the second connector  1 B. Subsequently, when the case  71  is mounted on the automatic transmission, the connector fitting body  1  can be moved loosely with respect to the automatic transmission by the bracket  36  and the connector fitting body  1  easily is arranged in the case hole  711  of the case  71 . 
     Subsequently, the control board  8  is arranged on the first connector  1 A of the connector fitting body  1 . At this time, the first end parts  212  of the respective first terminals  21  projecting toward the air side L 1  from the first connector  1 A are inserted into the through holes  81  of the control board  8 . Then, the first end parts  212  of the respective first terminals  21  are joined to the conductor portions  811  of the control board  8  by soldering or the like. Thereafter, the control board  8  is covered by the cover  82 . 
     (Functions and Effects) 
     The connector fitting body  1  of this embodiment is of a tightening type such that the first and second housings  2 ,  3  are fit by tightening the bolt  4  to the nut  5 . In the connector fitting body  1 , when the bolt  4  is tightened to the nut  5 , the large-diameter portion (first step)  411  of the head  41  of the bolt  4  presses the first housing  2  toward the second housing  3  and the general portion (second step)  51  of the nut  5  receives the second housing  3 . In this way, the first housing  2  approaches the second housing  3 . Then, the end surface  410  of the small-diameter portion  412  of the head  41  contacts (is seated on) the end surface  520  of the nut  5  and the bolt  4  is tightened to the nut  5 . 
     The bolt  4  and the nut  5  are made of the metal, and the first and second housings  2 ,  3  are made of the resin to ensure insulation properties. The first and second housings  2 ,  3  are lower in strength than the bolt  4  and the nut  5 . In the connector fitting body  1  of this embodiment, the metal materials higher in strength than the resin materials can be bonded by the direct contact of the bolt  4  with the nut  5 . 
     The contact of the end surface  410  of the small-diameter portion  412  on the head  41  of the bolt  4  with the end surface  520  of the nut  5  ensures that an axial force generated when the bolt  4  is tightened does not act as a compression force on the first project  221  of the first housing  2  and the second projection  321  of the second housing  3 . In this way, an excessive compression force does not act on the first and second projections  221 ,  321  when the bolt  4  is tightened. Thus, the first and second projections  221 ,  321  can be protected from damage, and a tightening torque of the bolt  4  need not be managed strictly. Further, a large tightening torque can also be dealt with. 
     One feature of the connector fitting body  1  to be mounted on the printed board is that the conductor pins serving as the first terminals  21  are arranged densely. The connector fitting body  1  of this embodiment includes 30 or more first terminals  21  and second terminals  31 . When the first connector  1 A including the first terminals  21  and the second connector  1 B including the second terminals  31  are fit, the first terminals  21  and the second terminals  31  simultaneously contact each other. Thus, at the time of this fitting, a tightening axial force acting in the axial direction L on the first connector  1 A (first housing  2 ) and the second connector  1 B (second housing  3 ) needs to be increased. 
     To increase the tightening axial force, the tightening torque of the bolt  4  needs to be increased. At this time, when the head  41  of the bolt  4  is seated on a surface to be tightened, the axial force applied to the surface to be tightened also increases. In a conventional connector fitting body  1 , a surface to be tightened is constituted by a housing made of a resin material. Thus, in the conventional connector fitting body  1 , a bolt  4  needs to be tightened while the axial force applied to the surface to be tightened is limited appropriately. 
     In contrast, in the connector fitting body  1  of this embodiment, the surface to be tightened is formed by the nut  5  made of metal. An axial force due to the tightening of the bolt  4  is less likely to act on the first and second projections  221 ,  321 . In this way, the axial force due to the tightening of the bolt  4  can be increased while the first and second projections  221 ,  321  are protected. 
     Therefore, according to the connector fitting body  1  of this embodiment, the first and second housings  2 ,  3  can be protected from damage when the bolt  4  is tightened and the tightening torque of the bolt  4  can be managed easily. 
     Further, the connector fitting body  1  was developed in consideration of use in the oil environment R 2  in which oil is used. Particularly, the oil-proof sealing member  43  for sealing the clearance between the large-diameter portion  411  and the bolt arrangement hole  22  is mounted on the outer periphery of the large-diameter portion  411  of the head  41  of the bolt  4 . By arranging this oil-proof sealing member  43 , the oil cannot pass through the clearance between the head  41  of the bolt  4  and the bolt arrangement hole  22 . Further, the sealing resin portion  243  for preventing the penetration of the oil is provided around the first terminals  21 . Furthermore, the outer peripheral sealing member  232  is mounted on the outer periphery of the first housing  2 . By these configurations, the leakage of the oil in the oil environment R 2  used in the automatic transmission to the control board  8  in the air environment R 1  or to the outside of the case  71  of the automatic transmission can be prevented. 
     Note that it is also possible not to use members for sealing the oil such as the oil-proof sealing member  43 , the sealing resin portion  243  and the outer peripheral sealing member  232  if the connector fitting body  1  is used in such an environment that liquid such as water or oil is not present. 
     Second Embodiment 
     A connector fitting body  1  of a second embodiment differs from the connector fitting body  1  of the first embodiment in that a collar  6  made of metal is used when a bolt  4  is fastened to a nut  5  as shown in  FIG. 11 . In the connector fitting body  1  of this embodiment, the collar  6  made of metal is mounted on the outer periphery of a shaft  42  of the bolt  4  and the bolt  4  is tightened to the nut  5  via the collar  6 . Further, as shown in  FIG. 12 , an end surface  620  of the collar  6  is in contact with an end surface  520  of the nut  5  with the bolt  4  tightened to the nut  5 . 
     As shown in  FIGS. 12 and 13 , the shaft  42  of the bolt  4  of this embodiment is coaxially connected to a head  41 , inserted into a bolt insertion hole  22 A provided in a first housing  2  and threadably engaged with the nut  5 . The bolt insertion hole  22 A penetrates through a facing plate  23  of the first housing  2 . The head  41  of the bolt  4  is arranged in a head portion recess  25  communicating with an air side L 1  of the bolt insertion hole  22 A. An external thread  421  is formed on a part to be engaged threadedly with the nut  5  on a tip side of the shaft  42  of the bolt  4 , but the external thread  421  is not formed on a base end side of the shaft  42 . 
     The collar  6  is made of metal, faces the nut  5  and is arranged between the outer periphery of the shaft  42  and the inner periphery of the bolt insertion hole  22 A. The collar  6  includes a large-diameter portion  61  serving as a first step for pressing the first housing  2  toward a second housing  3 . The nut  5  includes a general portion  51  serving as a second step for pressing the second housing  3  toward the first housing  2 . A center hole  60  into which the shaft  42  of the bolt  4  is inserted is formed in a central part of the collar  6 . 
     The collar  6  includes a small-diameter portion  62  formed on an end part on the side of the second housing  3  (oil side L 2 ) and the large-diameter portion  61  serving as the first step, larger in diameter than the small-diameter portion  62  and formed adjacent to the small-diameter portion  62  on the side of the first housing  2  (air side L 1 ). A first projecting portion  221  to be pressed toward the second housing  3  by the large-diameter portion  61  is formed in the bolt insertion hole  22 A. The first projecting portion  221  is located on an outer peripheral side of the small-diameter portion  62  and projects toward an inner peripheral side of the bolt insertion hole  22 A. The first projection  221  of this embodiment is formed by narrowing a part in an axial direction L of the bolt insertion hole  22 A. Further, the structure of the nut  5  and the structure of a second projection  321  of a nut arrangement hole  32  are the same as in the first embodiment. 
     As shown in  FIGS. 11 and 12 , since the collar  6  is used in this embodiment, a structure is employed that seals oil passing through outer and inner peripheral sides of the collar  6 . An oil-proof first sealing member  63  for sealing a clearance between the collar  6  and the bolt insertion hole  22 A is mounted on the outer periphery of the collar  6 . Further, an oil-proof second sealing member  64  containing a metal material for sealing a clearance between an end surface  410  of the head  41  and an end surface  611  of the collar  6  is mounted on the outer periphery of the shaft  42 . 
     The oil-proof first sealing member  63  is the same as in the case of the first embodiment. As shown in  FIG. 14 , the oil-proof second sealing member  64  includes the metal material called a sealing washer. The sealing washer includes a metal outer peripheral portion  641  made of a metal material on an outer peripheral side and a sealing inner peripheral portion  642  made of a sealing material such as rubber or resin on an inner peripheral side of the metal outer peripheral portion  641 . As the sealing inner peripheral portion  642  is compressed to provide sealability, the sealing washer comes into contact with a surface of a member facing the metal outer peripheral portion  641  to be tightened. 
     Besides using the sealing washer, a metal gasket or the like made of a metal material and having sealability can be used as the oil-proof first sealing member  63 . The oil-proof first sealing member  63  may have the part made of the metal material fastened by the bolt  4  and have a function of sealing oil or the like. 
     The other structures of the bolt  4  and the first housing  2 , first terminals  21 , second terminals  31 , the second housing  3 , the nut  5  and the like in the connector fitting body  1  of this embodiment are the same as in the case of the first embodiment. 
     (Assembling/Arranging Method of Connector Fitting Body  1 ) 
     When using the connector fitting body  1  of this embodiment as a relay connector, the oil-proof first sealing member  63  is mounted on the outer periphery of the collar  6  and this collar  6  is arranged in the bolt insertion hole  22 A of the first housing  2 . Further, the oil-proof second sealing member  64  is mounted on the outer periphery of the shaft  42  of the bolt  4 , and the bolt  4  is inserted through the inner peripheral side of the collar  6  and fastened to the nut  5  arranged in the second housing  3 . 
     Then, the collar  6  and the oil-proof second sealing member  64  are sandwiched between the head  41  of the bolt  4  and the nut  5 . At this time, the sealing inner peripheral portion  642  of the sealing washer constituting the oil-proof second sealing member  64  is squeezed to seal the clearance between the head  41  of the bolt  4  and the collar  6  on the inner peripheral side of the collar  6 . Further, the metal outer peripheral portion  641  of the sealing washer constituting the oil-proof second sealing member  64  is sandwiched between the head  41  and the collar  6 . In this way, an axial force due to the tightening of the bolt  4  can be received by the nut  5  made of the metal via the metal outer peripheral portion  641  of the sealing washer and the collar  6  made of the metal materials. 
     (Functions and Effects) 
     The connector fitting body  1  of this embodiment is of such a tightening type that the first and second housings  2 ,  3  are fit by tightening the bolt  4  to the nut  5  via the collar  6 . In this connector fitting body  1 , when the bolt  4  is tightened to the nut  5  via the collar  6 , the large-diameter portion (first step)  61  of the collar  6  presses the first housing  2  toward the second housing  3  and the general portion (second step)  51  of the nut  5  receives the second housing  3 . In this way, the first housing  2  approaches the second housing  3 . Then, as the end surface  410  of the head  41  of the bolt  4 , both end surfaces of the metal outer peripheral portion  641  of the sealing washer, the end surface  620  of the collar  6  and the end surface  520  of the nut  5  come into contact, the bolt  4  is tightened to the nut  5 . 
     The bolt  4 , the metal outer peripheral portion  641  of the sealing washer, the collar  6  and the nut  5  are made of the metal, and the first and second housings  2 ,  3  are made of the resin to ensure insulation properties. The first and second housings  2 ,  3  are lower in strength than the bolt  4 , the metal outer peripheral portion  641 , the collar  6  and the nut  5 . In the connector fitting body  1  of this embodiment, the metal materials higher in strength than the resin materials can be bonded by the successive contact of the bolt  4 , the metal outer peripheral portion  641 , the collar  6  and the nut  5  in the axial direction L. 
     By the successive contact of the bolt  4 , the metal outer peripheral portion  641 , the collar  6  and the nut  5  in the axial direction L, it can be suppressed that an axial force generated when the bolt  4  is tightened acts as a compression force on the first projection  221  of the first housing  2  and the second projection  321  of the second housing  3 . In this way, it can be prevented that an excessive compression force acts on the first and second projections  221 ,  321  when the bolt  4  is tightened. Thus, the first and second projections  221 ,  321  can be protected from damage, and a tightening torque of the bolt  4  need not be managed strictly. Further, a large tightening torque can also be dealt with. 
     Further, in the connector fitting body  1  of this embodiment, when the bolt  4  is tightened, a state where the oil-proof first sealing member  63  mounted on the outer periphery of the collar  6  is in contact with the bolt insertion hole  22 A of the first housing  2  is maintained and the oil-proof first sealing member  63  is managed easily. 
     Therefore, also in the connector fitting body  1  of this embodiment, the first and second housings  2 ,  3  can be protected from damage when the bolt  4  is tightened and the tightening torque of the bolt  4  can be easily managed. 
     Note that it is also possible not to use members for sealing the oil such as the oil-proof first sealing member  63 , the oil-proof second sealing member  64 , a sealing resin portion  243  and an outer peripheral sealing member  232  if the connector fitting body  1  is used in such an environment that liquid such as water or oil is not present. 
     Other functions, effects and the like of the connector fitting body  1  of this embodiment are the same as in the case of the first embodiment. Further, in this embodiment, constituent elements denoted by the same reference signs as those of the first embodiment are the same as in the case of the first embodiment. 
     The invention is not limited only to the respective embodiments and further different embodiments can be configured without departing from the scope of the invention. Further, the invention includes various modifications and modifications and the like within the scope of equivalents.