Patent Publication Number: US-2022231457-A1

Title: Connector assembly

Description:
TECHNICAL FIELD 
     This invention relates to a connector assembly comprising a first connector and a second connector mateable with each other. 
     BACKGROUND ART 
     For example, this type of connector assembly is disclosed in Patent Document 1. 
     As shown in  FIG. 22 , Patent Document 1 discloses a connector assembly  90  comprising a female connector (first connector)  92  and a male connector (second connector)  94 . As shown in  FIGS. 22 and 23 , the first connector  92  is formed with an opening  922  and a pressed portion  928 . The second connector  94  is provided with a bendable arm  942  which is resiliently deformable and a lock piece  944  supported by the bendable arm  942 . 
     Referring to  FIG. 23 , when the second connector  94  is mated with the first connector  92 , the lock piece  944  is engaged with a lock portion  926  of the opening  922 . As a result, the mated state is locked, and the second connector  94  is prevented from being removed. Upon mating the second connector  94  with the first connector  92 , first, the lock piece  944  is moved toward the opening  922  while being moved inward in the pitch direction (see two-dot chain line in  FIG. 23 ). Meanwhile, the bendable arm  942  is resiliently deformed. When being moved to the opening  922 , the lock piece  944  is moved outward in the pitch direction because of the resilient force of the bendable arm  942  and strikes the pressed portion  928 . At that time, a click sound is produced, and the click sound indicates that the second connector  94  has been mated with the first connector  92 . 
     PRIOR ART DOCUMENTS 
     Patent Document(s) 
     
         
         Patent Document 1: JP A 2009-54518 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     For example, when each of a first connector and a second connector comprises a large number of terminals, the force required for mating becomes large. In such a case, upon mating the second connector with the first connector, the movement speed (mating speed) of the second connector tends to be slow. When the mating speed is slow, the locking piece will gently strike the pressed portion, and the click sound might be small. Therefore, there is a request to produce a large click sound even when the mating speed is slow. Moreover, there is a request to remove the second connector with no additional operation for unlocking the mated state. 
     It is therefore an object of the present invention to provide a connector assembly comprising a lock mechanism which produces a large click sound even when the mating speed is slow and which can unlock the mated state with no additional operation. 
     Solution to Problem 
     An aspect of the present invention provides a connector assembly comprising a first connector and a second connector. The second connector is mateable with the first connector, which is located therebelow in an upper-lower direction, along the upper-lower direction. The first connector comprises a first housing and one or more first terminals. Each of the first terminals is held by the first housing. The first housing is provided with a slide surface, a lock surface, a catch surface and a guide portion. Each of the slide surface and the catch surface extends in the upper-lower direction. The catch surface is, at least in part, located below the slide surface. The lock surface has a deep end. The deep end is located at a rear end of the lock surface in a front-rear direction perpendicular to the upper-lower direction. The lock surface faces downward and extends from the deep end toward the slide surface in the front-rear direction. The guide portion is located forward of the slide surface. The second connector comprises a second housing and one or more second terminals. Each of the second terminals is held by the second housing. The second housing is provided with a spring portion, a locked portion and a guided portion. The spring portion has a fixed portion and a support portion and is resiliently deformable. The fixed portion is fixed to a fixing portion of the second housing. The support portion is connected to the fixed portion. The locked portion projects rearward from the support portion. The support portion extends upward from the locked portion. The locked portion is movable in the front-rear direction in accordance with a resilient deformation of the spring portion. The locked portion has a locked surface. The locked surface is an upper surface of the locked portion which faces upward. The guided portion is located forward of the spring portion. In a mating process in which the second connector is mated with the first connector, the second connector is moved downward while the guided portion is guided by the guide portion. In the mating process, the locked portion slides on the slide surface to be moved downward while being pressed against the slide surface. The lock surface intersects with a line segment which extends straight upward from the lock surface by a first angle of 90 degrees or less in a perpendicular plane defined by the upper-lower direction and the front-rear direction. When the second connector is under a separated state where the second connector is separated from the first connector, the locked surface intersects with another line segment which extends straight upward from the locked surface by a second angle of 90 degrees or less in the perpendicular plane. When the locked portion is moved downward beyond the slide surface in the mating process, the locked portion is moved rearward, and a second abutment portion of the locked portion is brought into abutment with a first abutment portion of the catch surface. A first distance D 11 , which is a distance along the front-rear direction between the first abutment portion and the guide portion, is shorter than a second distance D 21  which is another distance along the front-rear direction between the second abutment portion and the guided portion of the second connector under the separated state. Under a mated state where the first connector and the second connector are mated with each other, the locked surface is located below the lock surface, and the fixed portion of the spring portion is located forward of the lock surface. 
     Another aspect of the present invention provides a connector assembly comprising a first connector and a second connector. The second connector is mateable with the first connector, which is located therebelow in an upper-lower direction, along the upper-lower direction. The first connector comprises a first housing and one or more first terminals. Each of the first terminals is held by the first housing. The first housing is provided with a slide surface, a lock surface and a guide portion. The slide surface extends in the upper-lower direction. The lock surface has a deep end. The deep end is located at a rear end of the lock surface in a front-rear direction perpendicular to the upper-lower direction. The lock surface faces downward and extends from the deep end toward the slide surface in the front-rear direction. The guide portion is located forward of the slide surface. The second connector comprises a second housing and one or more second terminals. Each of the second terminals is held by the second housing. The second housing is provided with a spring portion, a locked portion and a guided portion. The spring portion has a fixed portion and a support portion and is resiliently deformable. The fixed portion is fixed to a fixing portion of the second housing. The support portion is connected to the fixed portion. The locked portion projects rearward from the support portion. The support portion extends upward from the locked portion. The locked portion is movable in the front-rear direction in accordance with a resilient deformation of the spring portion. The locked portion has a locked surface. The locked surface is an upper surface of the locked portion which faces upward. The guided portion is located forward of the spring portion. In a mating process in which the second connector is mated with the first connector, the second connector is moved downward while the guided portion is guided by the guide portion. In the mating process, the locked portion slides on the slide surface to be moved downward while being pressed against the slide surface. The lock surface intersects with a line segment which extends straight upward from the lock surface by a first angle of 90 degrees or less in a perpendicular plane defined by the upper-lower direction and the front-rear direction. When the second connector is under a separated state where the second connector is separated from the first connector, the locked surface intersects with another line segment which extends straight upward from the locked surface by a second angle of 90 degrees or less in the perpendicular plane. When the locked portion is moved downward beyond the slide surface in the mating process, the locked portion is moved rearward, and a second abutment portion of the locked portion is brought into abutment with a first abutment portion of the slide surface. A first other distance D 12 , which is a distance along the front-rear direction between the first abutment portion and the guide portion, is shorter than a second other distance D 22  which is a distance along the front-rear direction between the second abutment portion and the guided portion of the second connector under the separated state. Under a mated state where the first connector and the second connector are mated with each other, the locked surface is located below the lock surface, and the fixed portion of the spring portion is located forward of the lock surface. 
     Advantageous Effects of Invention 
     In the mating process of the connector assembly of the present invention, the locked portion supported by the resiliently deformable support portion slides on the slide surface to be moved downward while being pressed against the slide surface. In the present invention, each of the first angle, by which the lock surface intersects with the upper-lower direction, and the second angle, by which the locked surface of the locked portion intersects with the upper-lower direction, is 90 degrees or less. Moreover, in the present invention, the locked portion is arranged at a position so as to be brought into abutment with the catch portion, or the support portion of the spring portion is arranged at a position so as to be brought into abutment with the slide surface. According to the aforementioned structure, even when the mating speed in the mating process is slow, the locked portion is rapidly moved rearward, and the locked portion (support portion) strikes the catch surface (slide surface) at high speed. As a result, a large click sound is produced even when the mating speed is slow. 
     In addition, according to the present invention, the locked surface is located below the lock surface under the mated state, and thereby the mated state is locked. However, under the mated state, the support portion of the spring portion extends from the fixed portion, which is located forward of the lock surface, to the locked portion which is located below the lock surface. The thus-cantilevered support portion has a fulcrum which is located above and forward of the locked surface. When the second connector is pulled upward, the locked surface receives an upward force from the lock surface, and thereby a forward moment about the fulcrum of the support portion is applied to the spring portion. As a result, the locked portion is moved forward, and thereby the mated state is unlocked. Thus, according to the present invention, the mated state can be unlocked only by pulling the second connector upward. 
     As described above, the present invention provides a connector assembly comprising a lock mechanism which produces a large click sound even when the mating speed is slow and which enables the mated state to be unlocked with no additional operation. 
     An appreciation of the objectives of the present invention and a more complete understanding of its structure may be had by studying the following description of the preferred embodiment and by referring to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing a connector assembly according to an embodiment of the present invention, wherein a first connector and a second connector of the connector assembly are under a separated state where they are separated from each other. 
         FIG. 2  is a perspective view showing the connector assembly of  FIG. 1 , wherein the first connector and the second connector are under a mated state where they are mated with each other. 
         FIG. 3  is a perspective view showing the connector assembly of  FIG. 1 , wherein first terminals of the first connector and a part which holds the first terminals are not illustrated, and second terminals of the second connector and a part which holds the second terminals are not illustrated. 
         FIG. 4  is a top view showing the first connector of  FIG. 3 , wherein positions of the first terminals are illustrated with dashed line, and a rough outline of a part of the second connector which is received in a receiving space of the first connector is illustrated with chain dotted lines. 
         FIG. 5  is a bottom view showing the second connector of  FIG. 3 , wherein positions of the second terminals are illustrated with dashed line. 
         FIG. 6  is a side view showing the connector assembly of  FIG. 3 , wherein a part of a first housing is illustrated, a part of a second housing and a lever are illustrated, and a part of the first connector enclosed by dashed line and a part of the second connector enclosed by dashed line are enlarged and illustrated. 
         FIG. 7  is a perspective view showing the connector assembly of  FIG. 3 , wherein the second connector is partially received in the receiving space of the first connector, and a first protruding wall of the first housing is not illustrated. 
         FIG. 8  is a perspective view showing the connector assembly of  FIG. 7 , wherein a cover of the second connector is not illustrated. 
         FIG. 9  is a side view showing the connector assembly of  FIG. 6 , wherein the second connector is partially received in the receiving space of the first connector. 
         FIG. 10  is a perspective view showing the connector assembly of  FIG. 8 , wherein a projecting portion of the lever is partially received in a lever receiving portion of the first housing. 
         FIG. 11  is a side view showing the connector assembly of  FIG. 10 , wherein outlines of a spring portion and a locked portion under a state where the spring portion is not resiliently deformed are illustrated with dashed line. 
         FIG. 12  is a side view showing the connector assembly of  FIG. 11 , wherein the second connector is mated with the first connector, and a part of the connector assembly enclosed by dashed line is enlarged and illustrated. 
         FIG. 13  is a perspective view showing the connector assembly of  FIG. 10 , wherein the second connector is mated with the first connector, and the mated state is locked. 
         FIG. 14  is a side view showing the connector assembly of  FIG. 13 , wherein a part of the connector assembly enclosed by dashed line is enlarged and illustrated. 
         FIG. 15  is a perspective view showing the connector assembly of  FIG. 13 , wherein the lever is hooked on a lever stopper of the first connector. 
         FIG. 16  is a side view showing a modification of the connector assembly of  FIG. 14 , wherein a part of the connector assembly enclosed by dashed line is enlarged and illustrated, and in the enlarged view, outlines of the spring portion and the locked portion under a state where the spring portion is not resiliently deformed are illustrated with two-dot chain line. 
         FIG. 17  is a side view showing a modification of a first lock structure and a second lock structure of the connector assembly of  FIG. 14 , wherein outlines of the spring portion and the locked portion under a state where the spring portion is not resiliently deformed are illustrated with dashed line. 
         FIG. 18  is a side view showing another modification of the first lock structure and the second lock structure of  FIG. 14 , wherein outlines of the spring portion and the locked portion under a state where the spring portion is not resiliently deformed are illustrated with dashed line. 
         FIG. 19  is a side view showing still another modification of the first lock structure and the second lock structure of  FIG. 14 , wherein outlines of the spring portion and the locked portion under a state where the spring portion is not resiliently deformed are illustrated with dashed line. 
         FIG. 20  is a side view showing yet another modification of the first lock structure and the second lock structure of  FIG. 14 , wherein outlines of the spring portion and the locked portion under a state where the spring portion is not resiliently deformed are illustrated with dashed line. 
         FIG. 21  is a side view showing further modification of the first lock structure and the second lock structure of  FIG. 14 , wherein outlines of the spring portion and the locked portion under a state where the spring portion is not resiliently deformed are illustrated with dashed line. 
         FIG. 22  is a perspective view showing a connector assembly of Patent Document 1. 
         FIG. 23  is a perspective view showing a part of the connector assembly of  FIG. 22 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. 
     As shown in  FIGS. 1 and 2 , a connector assembly  10  of the present embodiment comprises a first connector  20  and a second connector  50 . In the present embodiment, the first connector  20  is a receptacle, and the second connector  50  is a plug. Moreover, the first connector  20  is a cable connector which is connected to a plurality of first cables  12  when used, and the second connector  50  is another cable connector which is connected to a plurality of second cables  14  when used. However, the present invention is not limited thereto. For example, the first connector  20  may be a plug, and the second connector  50  may be a receptacle. Moreover, each of the first connector  20  and the second connector  50  is not limited to a cable connector. 
     The first connector  20  and the second connector  50  are mateable with each other along an upper-lower direction (Z-direction: mating direction). More specifically, the second connector  50  is mateable with the first connector  20  along the Z-direction, wherein the first connector  20  is located therebelow in the Z-direction or faces the negative Z-side of the second connector  50 . The second connector  50  which is mated with the first connector  20  is removable from the first connector  20  along the Z-direction. 
     Referring to  FIGS. 1, 2 and 4 , the first connector  20  of the present embodiment comprises a first housing  30  made of insulator and a plurality of first terminals  22  each made of conductor. Each of the first terminals  22  is held by the first housing  30 . In the present embodiment, the first terminals  22  are connected to the first cables  12 , respectively, when the first connector  20  is used. Referring to  FIG. 4 , the number of the first terminals  22  of the present embodiment is twenty four. However, the present invention is not limited thereto, but the first connector  20  should comprise one or more of the first terminals  22 . 
     Referring to  FIGS. 1, 2 and 5 , the second connector  50  of the present embodiment comprises a second housing  60  made of insulator and a plurality of second terminals  52  each of which is made of conductor and which correspond to the first terminals  22  (see  FIG. 4 ), respectively. Each of the second terminals  52  is held by the second housing  60 . In the present embodiment, the second terminals  52  are connected to the second cables  14 , respectively, when the second connector  50  is used. Referring to  FIG. 5 , the number of the second terminals  52  of the present embodiment is twenty four. However, the present invention is not limited thereto, but the second connector  50  should comprise one or more of the second terminals  52 . 
     As shown in  FIGS. 3 and 5 , the second housing  60  of the present embodiment has a second peripheral wall  62 . The second peripheral wall  62  has a rectangular frame-like shape in a horizontal plane (XY-plane) perpendicular to the Z-direction so as to have two second side walls  66 . The second side walls  66  are located at opposite sides of the second peripheral wall  62 , respectively, in a lateral direction (Y-direction) perpendicular to the Z-direction. Each of the second side walls  66  extends along a perpendicular plane (XZ-plane) perpendicular to the Y-direction. The second housing  60  of the present embodiment has the aforementioned structure. However, the present invention is not limited thereto, but the structure of the second housing  60  can be variously modified. 
     Referring to  FIGS. 1 and 7 , the second connector  50  of the present embodiment comprises a lever  80  and two covers  88  each made of insulator in addition to the second housing  60  and the second terminals  52  (see  FIG. 5 ). Referring to  FIG. 8 , the lever  80  comprises an operation member  81  made of metal and two operated members  86  each made of insulator. The operation member  81  has an operation portion  82  and two arms  84  which correspond to the operated members  86 , respectively. The operation portion  82  extends along the Y-direction. The arms  84  linearly extend from opposite ends of the operation portion  82  in the Y-direction, respectively. Each of the arms  84  has an end attached to the corresponding operated member  86 . 
     Each of the operated members  86  has a rotation axis  862  and a projecting portion  868 . The operated members  86  correspond to the second side walls  66  of the second housing  60 , respectively. Each of the operated members  86  is attached to an outside surface of the corresponding second side wall  66  in the Y-direction so as to extend along the XZ-plane. Each of the operated members  86  is turnable about the rotation axis  862  in the XZ-plane. Each of the projecting portions  868  projects from the operated member  86  so as to be away from the operation member  81 . Referring to  FIGS. 7 and 8 , the covers  88  are attached to the outside surfaces of the second side walls  66  in the Y-direction, respectively, so as to cover the operated members  86  from its outer side in the Y-direction. 
     The second connector  50  of the present embodiment comprises the lever  80  and the covers  88  which are attached to the second housing  60  as described above. The illustrated lever  80  extends upward, or along the positive Z-direction, from the second housing  60  and extends forward, or along the positive X-direction, from the second housing  60  in a front-rear direction (X-direction) perpendicular to both the Y-direction and the Z-direction. As described later, the first connector  20  and the second connector  50  are mateable with each other by operating the lever  80 . However, the present invention is not limited thereto, but the lever  80  and the covers  88  may be provided as necessary. 
     As shown in  FIG. 3 , the first housing  30  of the present embodiment has a first peripheral wall  32  and a receiving space  34 . The first peripheral wall  32  encloses the receiving space  34  in the XY-plane. In other words, the receiving space  34  is a space which is enclosed by the first peripheral wall  32  in the XY-plane. The first peripheral wall  32  of the present embodiment is provided with a lever stopper  322  which is configured to hook the lever  80 . The lever stopper  322  projects forward from the first peripheral wall  32 . 
     Referring to  FIGS. 3 and 4 , the first peripheral wall  32  has a rectangular frame-like shape in the XY-plane so as to have two first protruding walls  36 , two first side walls  37  and two first rear walls  38 . Each of the first side walls  37  is a side wall which is located at a front side (positive X-side) of the first peripheral wall  32 . The first side walls  37  are located at opposite sides of the first peripheral wall  32  in the Y-direction, respectively. Each of the first side walls  37  extends along the perpendicular plane (XZ-plane) defined by the X-direction and the Z-direction. The first protruding walls  36  correspond to the first side walls  37 , respectively. Each of the first protruding walls  36  is located at the middle of the first peripheral wall  32  in the X-direction. Each of the first protruding walls  36  is located rearward, or at the negative X-side, of the corresponding first side wall  37  and outward of the corresponding first side wall  37  in the Y-direction, and extends along the XZ-plane. The first rear walls  38  correspond to the first protruding walls  36 , respectively. Each of the first rear walls  38  is located at a rear end (negative X-side end) of the corresponding first protruding wall  36  and extends along a predetermined plane defined by the Y-direction and the Z-direction. 
     Referring to  FIGS. 3 and 8 , the first housing  30  of the present embodiment has two lever receiving portions  362  which correspond to the operated members  86  of the lever  80 , respectively. The lever receiving portions  362  correspond to the first protruding walls  36 , respectively. Each of the lever receiving portions  362  is provided on an inside surface of the corresponding first protruding wall  36  in the Y-direction and protrudes inward in the Y-direction. Thus, each of the lever receiving portions  362  is located in the receiving space  34 . Referring to  FIG. 8 , each of the lever receiving portions  362  has a recess which can receive the projecting portion  868  of the corresponding operated member  86 . The recess of each of the lever receiving portions  362  opens forward. 
     The first housing  30  of the present embodiment has the aforementioned structure. However, the present invention is not limited thereto, but the structure of the first housing  30  can be variously modified. For example, when the second connector  50  does not comprise the lever  80 , the lever stopper  322  and the lever receiving portions  362  do not need to be provided. 
     Referring to  FIGS. 3 and 7 , in the present embodiment, the receiving space  34  of the first connector  20  has a shape which can receive the second peripheral wall  62  of the second connector  50  together with the operated members  86  and the covers  88 . In detail, referring to  FIGS. 4 and 5 , the receiving space  34  has a shape in the XY-plane which is substantially identical to another shape of a lower part (negative Z-side part) of the second connector  50  in the XY-plane. In particular, the receiving space  34  has a size in the X-direction which is slightly larger than another size of the lower part of the second connector  50  in the X-direction, and the receiving space  34  has a size in the Y-direction which is slightly larger than another size of the lower part of the second connector  50  in the Y-direction. 
     Referring to  FIGS. 3 and 7 , upon mating the second connector  50  with the first connector  20 , first, the second connector  50  is moved downward, and the second peripheral wall  62  of the second connector  50  is inserted into the receiving space  34  of the first connector  20  together with the operated members  86  and the covers  88 . Referring to  FIGS. 8 and 10 , then, the second connector  50  is further moved downward, and the projecting portions  868  of the operated members  86  are inserted into the recesses of the lever receiving portions  362 , respectively. Referring to  FIGS. 10 and 13 , then, the operation portion  82  of the lever  80  is pushed down. When the operation portion  82  is pushed down, the second connector  50  is further moved downward, and thereby the first connector  20  and the second connector  50  are mated with each other. 
     Referring to  FIG. 2 , under a mated state where the first connector  20  and the second connector  50  are mated with each other, each of the first terminals  22  (see  FIG. 4 ) is brought into contact with the corresponding second terminal  52  (see  FIG. 5 ), and thereby the first cables  12  are electrically connected with the second cables  14 , respectively. 
     Referring to  FIGS. 10 and 13 , upon removing the second connector  50  which is under the mated state from the first connector  20 , first, the operation portion  82  of the lever  80  is pulled up. When the operation portion  82  is pulled up, the second connector  50  is moved upward. Meanwhile, each of the second terminals  52  (see  FIG. 5 ) is separated from the corresponding first terminal  22  (see  FIG. 4 ). Referring to  FIGS. 8 and 10 , then, the second connector  50  is lifted up, and the projecting portions  868  of the operated members  86  are removed from the recesses of the lever receiving portions  362 , respectively. Referring to  FIGS. 3 and 7 , then, the second connector  50  is further moved upward, and the second peripheral wall  62  of the second connector  50  is removed from the receiving space  34  of the first connector  20  together with the operated members  86  and the covers  88 . As a result, the second connector  50  takes a separated state where the second connector  50  is separated from the first connector  20 . 
     In general, when the number of the first terminals  22  (see  FIG. 4 ) is large, a large force is required in order for the second terminals  52  (see  FIG. 5 ) to be brought into contact with the first terminals  22 , respectively. A large force is also required in order for the second terminals  52  to be separated from the first terminals  22 , respectively. Thus, when each of the first connector  20  and the second connector  50  is a multi-contact connector such as that of the present embodiment, a large force is usually required in each of a mating process in which the second connector  50  is mated with the first connector  20  and a removing process in which the second connector  50  is removed from the first connector  20 . Moreover, even when the number of the first terminals  22  is one, a large force is required in each of the mating process and the removing process depending on the size of the first terminal  22 . 
     In contrast, according to the present embodiment, the second connector  50  can be mated with the first connector  20  by operating the lever  80  with a relatively small force. In addition, the second connector  50  can be removed from the first connector  20  by operating the lever  80  with a relatively small force. However, the present invention is not limited thereto. For example, the second connector  50  may be directly pushed down to be mated with the first connector  20  without providing the lever  80 . Similarly, the second connector  50  may be directly pulled up to be removed from the first connector  20 . 
     Referring to  FIGS. 13 and 15 , in the present embodiment, the operation member  81  of the lever  80  is attached so as to be movable relative to the operated members  86 . When the second connector  50  is under the mated state, the operation member  81  can be moved rearward from the operated members  86 , and thereafter the operation portion  82  can be hooked on the lever stopper  322  of the first connector  20 . By hooking the operation portion  82  on the lever stopper  322 , the mated state can be prevented from being unlocked even when an unintentional force is applied to the operation portion  82 . However, the operation portion  82  may be hooked on the lever stopper  322  as necessary. 
     Referring to  FIGS. 3 and 4 , the first housing  30  is provided with two guide portions  48 . In the present embodiment, each of the guide portions  48  is a rear edge surface of the first side wall  37  of the first housing  30  and extends along the YZ-plane. Thus, each of the guide portions  48  is a flat surface which faces rearward and extends along the Z-direction. 
     Referring to  FIGS. 3 and 5 , the second housing  60  is provided with two guided portions  78  which correspond to the guide portions  48 , respectively. In the present embodiment, each of the guided portions  78  is a front edge surface (positive X-side surface) of a part of the second housing  60  which protrudes outward from the second side wall  66 , and each of the guided portions  78  extends along the YZ-plane. Thus, each of the guided portions  78  is a flat surface which faces forward and extends along the Z-direction. 
     Referring to  FIG. 7 , the guided portions  78  are formed at positions which correspond to those of the guide portions  48 , respectively. More specifically, when the second connector  50  is partially inserted into the receiving space  34  of the first connector  20 , each of the guided portions  78  is located rearward of the corresponding guide portion  48  with a slight distance from the corresponding guide portion  48  or is arranged to be in contact with the corresponding guide portion  48 . Moreover, the receiving space  34  has a size in the X-direction which is substantially equal to another size of the second peripheral wall  62  of the second connector  50  in the X-direction. Therefore, a distance between each of the guided portions  78  and the corresponding guide portion  48  in the X-direction is hardly changed during the mating process in which the second connector  50  is mated with the first connector  20 . 
     During the mating process of the second connector  50 , the guide portions  48  and the guided portions  78  which are arranged as described above prevent a movement of the second connector  50  in the X-direction and enable the second connector  50  to be reliably moved downward. In other words, in the mating process, the second connector  50  is moved downward while the guided portions  78  are guided by the guide portions  48 . 
     Referring to  FIGS. 4 and 5 , according to the present embodiment, the two guide portions  48  are located at positions same as each other in the X-direction, and the two guided portions  78  are located at positions same as each other in the X-direction. Referring to  FIG. 6 , each of the guide portions  48  and the guided portions  78  continuously and linearly extends along the Z-direction. Each of the guided portions  78  is located just in front of the corresponding guide portion  48 . However, the present invention is not limited thereto. The structure, number and arrangement of the guide portions  48  can be variously modified, provided that the position of each of the guided portions  78  in the X-direction is substantially equal to the position of the corresponding guide portion  48  in the X-direction during the mating process of the second connector  50 . Similarly, the structure, number and arrangement of the guided portion  78  can be variously modified. For example, each of the guided portions  78  may be located just behind the corresponding guide portion  48 . 
     Referring to  FIGS. 4 and 6 , the first connector  20  of the present embodiment has two first lock structures  39 . The first lock structures  39  are located at opposite sides of the first housing  30  in the Y-direction, respectively, and are located at positions same as each other in the X-direction. Referring to  FIGS. 4, 5 and 6 , the second connector  50  of the present embodiment has two second lock structures  69  which correspond to the first lock structures  39 , respectively. The second lock structures  69  are located at opposite sides of the second housing  60  in the Y-direction, respectively, and are located at positions same as each other in the X-direction. Thus, the connector assembly  10  of the present embodiment comprises two sets each of which consists of the first lock structure  39  and the second lock structure  69  corresponding to each other. 
     In the present embodiment, the two sets of the first lock structures  39  and the second lock structures  69  have structures similar to each other and similarly lock the mated state of the first connector  20  and the second connector  50 . Thus, the two sets of the first lock structures  39  and the second lock structures  69  work as a lock mechanism of the connector assembly  10 . However, the present invention is not limited thereto. For example, the two sets of the first lock structures  39  and the second lock structures  69  may have structures different from each other. The number of the sets of the first lock structures  39  and the second lock structures  69  is not limited to two but may be one or may be three or more. However, the present embodiment is preferable from a viewpoint of securely locking the mated state without excessively complicating the structure of the connector assembly  10 . Hereafter, explanation will be made about one set of the first lock structure  39  and the second lock structure  69  corresponding to each other. The explanation described below is applicable to each set. 
     Referring to  FIG. 4 , in the present embodiment, the first lock structure  39  is a front part of the first rear wall  38  of the first housing  30 . Referring to  FIGS. 6 and 8 , the first lock structure  39  includes a facing surface  40 , a sloping surface  41 , a slide surface  42 , a receiving recess  43 , a lock surface (upper wall surface)  44  and a catch surface (rear wall surface)  46 . Thus, the first housing  30  is provided with the facing surface  40 , the sloping surface  41 , the slide surface  42 , the receiving recess  43 , the lock surface  44  and the catch surface  46 . 
     The facing surface  40  is formed on an upper part (positive Z-side part) of the first rear wall  38 . The facing surface  40  faces forward and extends along the Z-direction. The sloping surface  41  faces forward and extends from a lower end (negative Z-side end) of the facing surface  40  to the slide surface  42  while sloping forward and downward. The slide surface  42  has an upper end  428  and faces forward. In particular, the slide surface  42  of the present embodiment extends straight along the Z-direction from the upper end  428 . Thus, the slide surface  42  of the present embodiment is a flat surface perpendicular to the X-direction. However, the shape of the slide surface  42  is not limited to that of the present embodiment, provided that the slide surface  42  extends in the Z-direction. For example, the slide surface  42  may be a flat surface oblique to the X-direction or may be a curved surface intersecting with the X-direction. 
     The receiving recess  43  is a recess which is recessed rearward from the slide surface  42 . The catch surface  46  is the rear wall surface of the receiving recess  43 . Thus, the catch surface  46  is located below the slide surface  42  and faces forward. The catch surface  46  has an upper end  468 . The catch surface  46  of the present embodiment is located rearward of the slide surface  42  in the X-direction and extends straight downward from the upper end  468  along the Z-direction. Thus, the catch surface  46  is a flat surface perpendicular to the X-direction. However, the shape of the catch surface  46  is not limited to that of the present embodiment, provided that the catch surface  46  extends in the Z-direction. For example, the catch surface  46  may be a flat surface oblique to the X-direction or may be a curved surface intersecting with the X-direction. 
     The lock surface  44  is an upper wall surface of the receiving recess  43 . The lock surface  44  has a deep end  448 . The deep end  448  is located at a rear end of the lock surface  44  in the X-direction. The lock surface  44  faces downward and extends from the deep end  448  toward the slide surface  42  in the X-direction. In the present embodiment, the deep end  448  is located at a position same as that of the upper end  468  of the catch surface  46 . Thus, the lock surface  44  of the present embodiment is located between the slide surface  42  and the catch surface  46  in the X-direction and extends from the upper end  468  of the catch surface  46  toward the slide surface  42 . 
     Referring to  FIG. 5 , in the present embodiment, the second lock structure  69  is provided to be located outward of the second side wall  66  of the second housing  60  in the Y-direction. Referring to  FIGS. 6 and 8 , the second lock structure  69  includes a spring portion  70  and a locked portion  72 . Thus, the second housing  60  is provided with the spring portion  70  and the locked portion  72 . 
     Referring to  FIG. 6 , the spring portion  70  has a fixed portion  702  and a support portion  704 . The fixed portion  702  is fixed to the second housing  60 . In detail, the second side wall  66  of the second housing  60  is formed with a fixing portion  68  which protrudes outward in the Y-direction. The fixed portion  702  is fixed to the fixing portion  68  of the second housing  60 . The support portion  704  is connected to the fixed portion  702 . The spring portion  70  which is formed as described above is resiliently deformable. 
     According to the present embodiment, when the second connector  50  is under the separated state, the fixed portion  702  extends rearward from the fixing portion  68 , and the support portion  704  extends long downward from a rear end  703  of the fixed portion  702 . Thus, the spring portion  70  has an L-like shape in the XZ-plane and extends downward from the fixing portion  68  as a whole. The spring portion  70  which is formed as described above is resiliently deformable easily as a whole. However, the present invention is not limited thereto; and the shape of the spring portion  70  is not specifically limited, provided that the spring portion  70  is resiliently deformable. For example, the fixed portion  702  may be an edge surface of the spring portion  70 , and the support portion  704  may extend rearward and downward from the fixed portion  702 . 
     The support portion  704  has a support surface  706  and a lower end  708 . The support surface  706  is a rear edge surface of the support portion  704 . The support surface  706  faces rearward and extends along the Z-direction. The lower end  708  is a lower end of the support surface  706 . 
     The locked portion  72  is provided on a lower end of the support portion  704 . In other word, the support portion  704  extends upward from the locked portion  72 . The thus-provided locked portion  72  is movable in the X-direction in accordance with a resilient deformation of the spring portion  70 . The locked portion  72  projects rearward from the support portion  704 . The locked portion  72  has a hook-like shape and has a locked surface (upper surface)  74  and a leading edge  722  in the X-direction. The locked surface  74  is an upper surface of the locked portion  72  which faces upward. When the second connector  50  is under the separated state, the spring portion  70  is not resiliently deformed, i.e., it is not bent, and the locked surface  74  projects rearward from the support surface  706  to the leading edge  722 . 
     Referring to  FIGS. 8 and 9 , when the second connector  50  is partially inserted into the receiving space  34  of the first connector  20  in the mating process, the spring portion  70  and the locked portion  72  are located forward of the facing surface  40  while being apart from the facing surface  40 . In other words, the facing surface  40  faces the spring portion  70  and the locked portion  72  in the X-direction. The spring portion  70  under this state is not resiliently deformed. 
     Referring to  FIG. 9 , in the first connector  20 , the guide portion  48  is apart from the slide surface  42  and is located forward of the slide surface  42 . In the second connector  50 , the guided portion  78  is apart from the spring portion  70  and is located forward of the spring portion  70 . Moreover, as previously described, in the connector assembly  10  during the mating process, the position of the guided portion  78  in the X-direction can be considered to be equal to the position of the guide portion  48  in the X-direction. 
     Referring to  FIG. 6 , according to the present embodiment, in the second connector  50  which is under the separated state, i.e., a state where the spring portion  70  is not resiliently deformed, the support surface  706  of the spring portion  70  is a flat surface perpendicular to the X-direction, and the leading edge  722  of the locked portion  72  is located at a rear end of the locked portion  72 . Under the separated state, a distance between the leading edge  722  and the guided portion  78  along the X-direction is a second distance D 21 , and a distance between the support surface  706  and the guided portion  78  along the X-direction is a second other distance D 22 . In the first connector  20  of the present embodiment, each of the slide surface  42  and the catch surface  46  is a flat surface perpendicular to the X-direction. A distance between the catch surface  46  and the guide portion  48  along the X-direction is a first distance D 11 , and a distance between the slide surface  42  and the guide portion  48  along the X-direction is a first other distance D 12 . 
     Referring to  FIG. 9 , the second distance D 21  is larger than the first other distance D 12 . Thus, under a state shown in  FIG. 9 , the leading edge  722  of the locked portion  72  is located rearward of the upper end  428  of the slide surface  42 . As can be seen from  FIG. 9 , when the second connector  50  is further moved downward in the mating process, the locked portion  72  is brought into contact with the sloping surface  41  because of the positional relation described above. When the second connector  50  is further moved downward, the locked portion  72  gradually resiliently deforms the spring portion  70  while sliding on the sloping surface  41  to be moved downward. When the spring portion  70  is resiliently deformed, the second side wall  66  of the second connector  50  receives a forward force. As a result, the guided portion  78  is prevented from being moved to be away from the corresponding guide portion  48  in the X-direction. 
     In the present embodiment, the facing surface  40  is a flat surface in parallel to the YZ-direction, and the sloping surface  41  is a flat surface in parallel to the Y-direction but oblique to the Z-direction. However, the present invention is not limited thereto. For example, the sloping surface  41  may be a curved surface. Moreover, the facing surface  40  may not be provided, and the sloping surface  41  may be formed to slope forward and downward from an upper end of the first rear wall  38 . 
     Referring to  FIG. 11 , when the second connector  50  is further moved downward, the locked portion  72  rides on the slide surface  42  with a further resilient deformation of the spring portion  70  and then slides on the slide surface  42  to be moved downward. In other words, in the mating process of the second connector  50 , the locked portion  72  slides on the slide surface  42  to be moved downward while being pressed against the slide surface  42  by a spring force of the spring portion  70 . 
     Referring to  FIGS. 12 and 14 , when the locked portion  72  is moved downward beyond the slide surface  42  in the mating process of the second connector  50 , the locked portion  72  is strongly pushed toward the catch surface  46  by the spring force of the spring portion  70 . Referring to  FIG. 6 , the lock surface  44  of the first connector  20  intersects with a line segment LS 1  which extends straight upward from the lock surface  44  by a first angle θ 1  of 90 degrees or less in the XZ-plane. In addition, when the second connector  50  is under the separated state, the locked surface  74  of the locked portion  72  intersects with a line segment LS 2  which extends straight upward from the locked surface  74  by a second angle of 90 degrees same as the first angle θ 1  in the XZ-plane. 
     Referring to  FIG. 14 , according to the aforementioned angle condition, the locked surface  74 , which is moved downward beyond the slide surface  42 , is moved toward the catch surface  46  with little or no friction on a lower end part of the slide surface  42 . Meanwhile, since the support portion  704  extends upward from the locked portion  72 , the locked portion  72  is moved in a substantially straight line along the X-direction. Thus, the locked portion  72  is rapidly moved rearward by the rearward spring force while receiving little or no forward force such as a friction force. 
     Referring to  FIG. 6  together with  FIG. 14 , the first distance D 11 , which is a distance along the X-direction between the guide portion  48  and a first abutment portion  462  which is a part of the catch surface  46 , is shorter than the second distance D 21  which is a distance along the X-direction between the guided portion  78  and the leading edge (second abutment portion)  722  of the locked portion  72  of the second connector  50  under the separated state. 
     Referring to  FIG. 14 , the second abutment portion  722  of the locked portion  72 , which is rapidly moved toward the catch surface  46 , strikes the first abutment portion  462  of the catch surface  46  because of the aforementioned distance condition, and thereby a clear click sound is produced, and click feeling can be obtained. 
     Referring to  FIG. 6 , in the present embodiment, a first predetermined distance DP 1  which is a distance along the X-direction between the slide surface  42  and the upper end  468  of the catch surface  46  is shorter than a second predetermined distance DP 2  which is a distance along the X-direction between the lower end  708  of the support surface  706  and the leading edge  722  of the locked portion  72  of the second connector  50  under the separated state. However, the relation between the first predetermined distance DP 1  and the second predetermined distance DP 2  is not specifically limited, provided that the second abutment portion  722  of the locked portion  72  is brought into abutment with the first abutment portion  462  of the catch surface  46 . 
     Referring to  FIG. 14 , under the mated state, the locked surface  74  is located below the lock surface  44 . This arrangement locks the mated state. However, under the mated state, the fixed portion  702  of the spring portion  70  is located forward of the lock surface  44 . The support portion  704  of the spring portion  70  extends from the fixed portion  702 , which is located forward of the lock surface  44 , to the locked portion  72  which is located below the lock surface  44 . The thus-cantilevered spring portion  70  has a fulcrum which is a boundary portion between the fixing portion  68  and the fixed portion  702  and which is located above and forward of the locked surface  74 . When the second connector  50  is pulled upward, the locked surface  74  receives an upward force from the lock surface  44 , and thereby a forward moment about the fulcrum of the spring portion  70  is applied to the spring portion  70 . As a result, the locked portion  72  is moved forward, and thereby the mated state is unlocked. Thus, according to the present embodiment, the second connector  50  is friction locked, and the mated state can be unlocked only by pulling the second connector  50  upward. 
     In particular, according to the present embodiment, the whole spring portion  70  is located forward of the lock surface  44  under the mated state. This structure makes the mated state to be easily unlocked. In addition, the locked surface  74  of the present embodiment extends toward the support portion  704  while sloping upward. In detail, the locked surface  74  intersects with a line segment LSL which extends forward from the locked surface  74  by an angle α of more than zero degree in the XZ-plane. When the second connector  50  is pulled upward, the locked surface  74  receives a forward force from the lock surface  44  to be moved forward. Thus, according to the present embodiment, the mated state can be further easily unlocked. 
     Referring to  FIG. 6 , in the present embodiment, the lock surface  44  is a flat surface perpendicular to the Z-direction, and the locked surface  74  under the separated state is a flat surface perpendicular to the Z-direction. However, the shape of each of the lock surface  44  and the locked surface  74  can be variously modified. For example, each of the lock surface  44  and the locked surface  74  under the separated state may be a flat surface in parallel to the Y-direction but oblique to the Z-direction. In detail, the first angle θ 1  should be 90 degrees or less, and the second angle θ 2  should be 90 degrees or less. Referring to  FIG. 12 , according to this angle condition, when the locked portion  72  is moved t downward beyond the slide surface  42  in the mating process, the locked portion  72  is rapidly moved rearward. 
     As previously described, the spring portion  70  of the present embodiment has an L-like shape in the XZ-plane. The spring portion  70  of an L-like shape moves the locked portion  72  rearward by a strong spring force when the locked portion  72  is moved downward beyond the slide surface  42 . In addition, the spring portion  70  of an L-like shape is easily bent, and thereby the mated state can be further easily unlocked. 
     Referring to  FIG. 14 , the spring portion  70  of the present embodiment is a part of the second housing  60 . In particular, the spring portion  70  is made of resin and is formed integrally with the second housing  60 . The spring portion  70  made of resin is easily bent, and thereby the mated state can be easily unlocked even when the angle α is extremely close to zero, or when the angle α is 3 degrees or less, for example. However, the present invention is not limited thereto. For example, the spring portion  70  may be made of metal. 
     A structure for producing a clear click sound is not limited to that of the present embodiment but can be variously modified as describe below. 
     Comparing  FIG. 16  with  FIG. 14 , a connector assembly  10 A according to a modification of the present embodiment comprises a first connector  20 A slightly different from the first connector  20  and a second connector  50 A slightly different from the second connector  50 . The first connector  20 A comprises a first housing  30 A slightly different from the first housing  30 , and the second connector  50 A comprises a second housing  60 A slightly different from the second housing  60 . The first housing  30 A is provided with a receiving recess  43 A and a lock surface (upper wall surface)  44 A instead of the receiving recess  43  and the lock surface  44 , and the second housing  60 A is provided with a locked portion  72 A and a locked surface (upper surface)  74 A instead of the locked portion  72  and the locked surface  74 . Except for these differences, the first connector  20 A has a structure same as that of the first connector  20 , and the second connector  50 A has a structure same as that of the second connector  50 . 
     In the present modification, the receiving recess  43 A is recessed rearward by a distance larger than that of the receiving recess  43 . As a result, the size of the lock surface  44 A in the X-direction is larger than the size of the lock surface  44  in the X-direction. Moreover, the locked portion  72 A projects rearward by a distance shorter than that of the locked portion  72 . As a result, the size of the locked surface  74 A in the X-direction is smaller than the size of the locked surface  74  in the X-direction. 
     Referring to  FIG. 16  together with  FIG. 6 , in the present modification, the first predetermined distance DP 1  which is a distance along the X-direction between the slide surface  42  and the upper end  468  of the catch surface  46  is longer than the second predetermined distance DP 2  which is a distance along the X-direction between the lower end  708  of the support surface  706  and the leading edge  722  of the locked portion  72 A of the second connector  50  under the separated state. In addition, the first other distance D 12  which is a distance along the X-direction between the guide portion  48  and the upper end (first abutment portion)  428  of the slide surface  42  is shorter than the second other distance D 22  which is a distance along the X-direction between the guided portion  78  and the second abutment portion  707 , or a part of the support portion  704  of the second connector  50  under the separated state. 
     According to the aforementioned distance condition, when the locked portion  72 A is rapidly moved rearward, the second abutment portion  707  of the support portion  704  strikes the first abutment portion  428  of the slide surface  42 , and thereby a clear click sound is produced, and click feeling can be obtained. 
     According to the present modification, the first predetermined distance DP 1  is longer than the second predetermined distance DP 2 , and the locked portion  72  is not brought into abutment with the catch surface  46 . However, the present invention is not limited thereto. For example, the first predetermined distance DP 1  may be equal to the second predetermined distance DP 2 . In this instance, the second abutment portion  707  of the support portion  704  of the spring portion  70  is brought into abutment with the first abutment portion  428  of the slide surface  42 , and the leading edge (second abutment portion)  722  of the locked portion  72 A, which is rapidly moved toward the catch surface  46 , is also brought into abutment with the first abutment portion  462  (see  FIG. 14 ) of the catch surface  46 . As a result, a further clear click sound is produced. Thus, in the present modification, the first predetermined distance DP 1  may be equal to or longer than the second predetermined distance DP 2 . 
     Moreover, the first connector  20 A of the present modification does not need to comprise the catch surface  46 . For example, the first rear wall  38  of the first housing  30  may be formed with a hole which passes through the first rear wall  38  in the X-direction instead of the receiving recess  43 A. In this instance, the first predetermined distance DP 1  cannot be defined. As can be seen from the explanation described above, the relation between the first predetermined distance DP 1  and the second predetermined distance DP 2  of the present modification is not specifically limited. 
     Referring to  FIGS. 14 and 16 , according to the aforementioned embodiment, the leading edge  722 , i.e., a point or a line segment, of the locked portion  72  made of resin is brought into abutment with the catch surface  46  made of resin, and according to the aforementioned modification, the spring portion  70  made of resin is brought into abutment with the upper end  428 , i.e., a point or a line segment, of the slide surface  42  made of resin. According to the aforementioned embodiment and modification, a clear click sound is produced even in an instance where the parts which strike each other are made of resin since the parts strike each other at an extremely small strike area. However, the present invention is not limited thereto, but the parts which strike each other may be made of metal. 
     Referring to  FIGS. 6 and 16 , according to the aforementioned embodiment and modification, each of the slide surface  42  and the catch surface  46  is a flat surface in parallel to the YZ-plane. According to these shapes, the first distance D 11 , which is a distance between the first abutment portion  462  (see  FIG. 14 ) and the guide portion  48  along the X-direction, is equal to another distance, namely a catcher distance, between the catch surface  46  and the guide portion  48  along the X-direction, and the first other distance D 12 , which is a distance between the first abutment portion  428  (see  FIG. 16 ) and the guide portion  48  along the X-direction, is equal to another distance, namely a slider distance, between the slide surface  42  and the guide portion  48  along the X-direction. Moreover, the first angle θ 1  is an angle between the slide surface  42  and the lock surface  44 . 
     However, the present invention is not limited to the aforementioned embodiment and modification. For example, each of the slide surface  42  and the catch surface  46  may be a sloping surface in parallel to the Y-direction but oblique to the Z-direction. In this instance, the catcher distance varies depending on the part of the catch surface  46 , and the slider distance varies depending on the part of the slide surface  42 . However, even in this instance, the first distance D 11  is a distance between the first abutment portion  462  (see  FIG. 14 ) and the guide portion  48  along the X-direction, and the first other distance D 12  is a distance between the first abutment portion  428  (see  FIG. 16 ) and the guide portion  48  along the X-direction. 
     According to the aforementioned embodiment and modification, under the separated state, the support surface  706  is a flat surface in parallel to the YZ-plane, and a rear edge surface, which includes the leading edge  722  of the locked portion  72  (locked portion  72 A), is a flat surface in parallel to the YZ-plane. According to these shapes, the second distance D 21 , which is a distance along the X-direction between the second abutment portion  722  and the guided portion  78  under the separated state, is equal to another distance, namely a locker distance, along the X-direction between the guided portion  78  and the rear edge surface of the locked portion  72  (locked portion  72 A) under the separated state, and the second other distance D 22 , which is a distance along the X-direction between the second abutment portion  707  and the guided portion  78  under the separated state, is equal to another distance, namely a supporter distance, along the X-direction between the support surface  706  and the guided portion  78  under the separated state. Moreover, the second angle θ 2  is an angle between the support surface  706  and the locked surface  74 . 
     However, the present invention is not limited to the aforementioned embodiment and modification. For example, each of the support surface  706  and the rear edge surface of the locked portion  72  (locked portion  72 A) under the separated state may be a sloping surface in parallel to the Y-direction but oblique to the Z-direction. In this instance, the locker distance varies depending on the part of the rear edge surface of the locked portion  72  (locked portion  72 A), and the supporter distance varies depending on the part of the support surface  706 . However, even in this instance, the second distance D 21  is a distance along the X-direction between the second abutment portion  722  and the guided portion  78  under the separated state, and the second other distance D 22  is a distance along the X-direction between the second abutment portion  707  and the guided portion  78  under the separated state. 
     Referring to  FIG. 16 , according to the modification of  FIG. 16 , each of the slide surface  42  and the support surface  706  under the separated state is a flat surface perpendicular to the X-direction as described above. According to these shapes, the second abutment portion  707 , which is a part of the support portion  704 , is brought into abutment with the upper end  468  of the slide surface  42 . However, the present invention is not limited thereto. For example, by forming one of the slide surface  42  and the support surface  706  under the separated state into a flat surface oblique to the X-direction, a part of the support portion  704  can be brought into abutment with a lower end of the slide surface  42 . 
     Referring to  FIGS. 14 and 16 , according to the aforementioned embodiment and modification, the sloping surface  41  extends to the upper end  428  of the slide surface  42 . In contrast, a boundary portion between the slide surface  42  and the lock surface  44  (lock surface  44 A) is chamfered to be formed with a sloping edge. Thus, a lower end of the slide surface  42  and a front end of the lock surface  44  (lock surface  44 A) are apart from each other. However, the present invention is not limited thereto. For example, the slide surface  42  may extend to the front end of the lock surface  44  (lock surface  44 A). 
     According to the embodiment and modification, the lock surface  44  (lock surface  44 A) is perpendicular to the Z-direction, and the receiving recess  43  (receiving recess  43 A) is located only below the slide surface  42 . However, the present invention is not limited thereto. For example, the lock surface  44  (lock surface  44 A) may extend rearward and upward from the slide surface  42 . In this instance, the receiving recess  43  (receiving recess  43 A) is partially located above the slide surface  42 , and the upper end  468  of the catch surface  46  is located above the lower end of the slide surface  42 . Thus, the catch surface  46  should be, at least in part, located below the slide surface  42 . 
     Summarizing the explanation described above, according to the aforementioned embodiment and modification, each of the first angle θ 1 , by which the lock surface  44  (lock surface  44 A) intersects with the Z-direction, and the second angle θ 2 , by which the locked surface  74  (locked surface  74 A) of the locked portion  72  (locked portion  72 A) intersects with the Z-direction, is 90 degrees or less. Moreover, according to the aforementioned embodiment and modification, the locked portion  72  is located at a position so as to be brought into abutment with the catch surface  46 , or the support portion  704  of the spring portion  70  is located at a position so as to be brought into abutment with the slide surface  42 . 
     Referring to  FIGS. 14 and 16 , according to the aforementioned structure, even when a mating speed in the mating process is slow, the locked portion  72  (locked portion  72 A) is rapidly moved rearward. Because of this rapid movement, the locked portion  72  strikes the catch surface  46  at high speed, or the support portion  704  strikes the slide surface  42  at high speed. As a result, a large click sound is produced even when the mating speed is slow, and the large click sound indicates that the first connector  20  (first connector  20 A) and the second connector  50  (second connector  50 A) have been mated with each other. 
     As described above, the present invention provides the connector assembly  10  comprising the lock mechanism which produces a large click sound even when the mating speed is slow and which enables the mated state to be unlocked with no additional operation. 
     Referring to  FIG. 14 , the structure of the connector assembly  10  can be further variously modified in addition to the already described modifications. Hereafter explanation will be made about some modifications of the first lock structure  39  of the first connector  20  and the second lock structure  69  of the second connector  50 . 
     As shown in  FIG. 17 , in the spring portion  70  of the second lock structure  69 , the fixed portion  702  may be an edge surface, and the support portion  704  may extend in arc from the fixed portion  702 . According to the illustrated modification, the second abutment portion  722  of the locked portion  72  is brought into abutment with the first abutment portion  462  of the catch surface  46 . However, the support portion  704  can be brought into abutment with the slide surface  42  by shifting the position of the slide surface  42  forward in the X-direction, for example. 
     As shown in  FIG. 18 , in the first lock structure  39 , the slide surface  42  may be a curved surface. According to the illustrated modification, the sloping surface  41  (see  FIG. 17 ) is not provided, and the slide surface  42  extends from the facing surface  40 . Moreover, according to the illustrated modification, the second abutment portion  722  of the locked portion  72  is brought into abutment with the first abutment portion  462  of the catch surface  46 . However, the support portion  704  can be brought into abutment with the slide surface  42  by shifting the position of the lower end of the slide surface  42  forward in the X-direction, for example. 
     As shown in  FIG. 19 , in the first lock structure  39 , the catch surface  46  may be located at a position same as that of the facing surface  40  in the X-direction. According to the illustrated modification, the second abutment portion  707  of the support portion  704  is brought into abutment with the first abutment portion  428  of the slide surface  42 . However, the locked portion  72  can be brought into abutment with the catch surface  46  by shifting the position of the slide surface  42  rearward in the X-direction, for example. 
     As shown in  FIG. 20 , in the first lock structure  39 , the catch surface  46  may be a sloping surface. According to the illustrated modification, the second abutment portion  722  of the locked portion  72  is brought into abutment with the first abutment portion  462  of the catch surface  46 . However, the support portion  704  can be brought into abutment with the slide surface  42  by shifting the position of the slide surface  42  forward in the X-direction, for example. 
     As shown in  FIG. 21 , in the first lock structure  39 , the catch surface  46  may be a sloping surface which is located below and apart from the lock surface  44 . According to the illustrated modification, a part of the lock surface  44  is located rearward of the slide surface  42 , and another part of the lock surface  44  is located forward of the slide surface  42 . According to the illustrated modification, a second abutment portion  723  of the locked portion  72  which is located below the leading edge  722  is brought into abutment with the first abutment portion  462  of the catch surface  46 . However, the support portion  704  can be brought into abutment with the slide surface  42  by shifting the position of the slide surface  42  forward in the X-direction, for example. Moreover, even in an instance where the whole catch surface  46  is located forward of the slide surface  42 , the second abutment portion  723  of the locked portion  72  can be brought into abutment with the first abutment portion  462  of the catch surface  46  by changing the shape of the locked portion  72 . According to this structure, the first predetermined distance DP 1  (see  FIG. 6 ) cannot be defined. 
     The present application is based on a Japanese patent application of JP2019-140748 filed on Jul. 31, 2019 before the Japan Patent Office, the content of which is incorporated herein by reference. 
     While there has been described what is believed to be the preferred embodiment of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such embodiments that fall within the true scope of the invention. 
     REFERENCE SIGNS LIST 
     
         
         
           
               10 , 10 A connector assembly 
               12  first cable 
               14  second cable 
               20 , 20 A first connector 
               22  first terminal 
               30 , 30 A first housing 
               32  first peripheral wall 
               322  lever stopper 
               34  receiving space 
               36  first protruding wall 
               362  lever receiving portion 
               37  first side wall 
               38  first rear wall 
               39  first lock structure 
               40  facing surface 
               41  sloping surface 
               42  slide surface 
               428  upper end (first abutment portion) 
               43 , 43 A receiving recess 
               44 , 44 A lock surface (upper wall surface) 
               448  deep end 
               46  catch surface (rear wall surface) 
               462  first abutment portion 
               468  upper end 
               48  guide portion 
               50 , 50 A second connector 
               52  second terminal 
               60 , 60 A second housing 
               62  second peripheral wall 
               66  second side wall 
               68  fixing portion 
               69  second lock structure 
               70  spring portion 
               702  fixed portion 
               703  rear end 
               704  support portion 
               706  support surface 
               707  second abutment portion 
               708  lower end 
               72 , 72 A locked portion 
               722  leading edge (second abutment portion) 
               723  second abutment portion 
               74 , 74 A locked surface (upper surface) 
               78  guided portion 
               80  lever 
               81  operation member 
               82  operation portion 
               84  arm 
               86  operated member 
               862  rotation axis 
               868  projecting portion 
               88  cover