Patent Publication Number: US-11398701-B2

Title: Wafer connector and fitting connector

Description:
TECHNICAL FIELD 
     One aspect of the present disclosure relates to a wafer connector and a fitting connector. 
     BACKGROUND 
     In the related art, various types of stacked type wafer connectors and fitting connectors are known. Patent Document 1 describes a multi-stage connector including a first housing, a second housing, and a cover. In the multi-stage connector, the first housing, the second housing, and the cover enter box-like mating connector in a state where the first housing, the second housing, and the cover are stacked on each other. The cover includes a lock piece to be engaged with the mating connector, and the multi-stage connector is fitted to the mating connector by engagement of the lock piece of the cover. 
     CITATION LIST 
     Patent Documents 
     [Patent Document 1] JP 10-79273 A 
     SUMMARY 
     Technical Problem 
     Incidentally, regarding a stack type wafer connector such as the multi-stage connector described above, enhancement in operability of insertion and removal has been demanded. However, in the above-described multi-stage connector, since the cover, instead of the first housing and the second housing, engages with the mating connector, the mating connector cannot be fitted unless the cover is attached to the second housing. In the multi-stage connector described above, the first housing or the second housing alone cannot be inserted into or removed from the mating connector, and the cover is always required to perform such insertion and removal. Also in this respect, operation of insertion and removal cannot be performed easily. Accordingly, there is a need for a wafer connector and a fitting connector that can improve the workability of insertion and removal. 
     Solution to Problem 
     A wafer connector according to one aspect of the present disclosure is a wafer connector of a stacked type configured to be electrically fitted to a fitting connector, and includes a wafer with an electrical insulation, defining a cavity configured to receive a terminal in the wafer, a latch engaging member including an engaging portion, being integrally formed with the wafer, and including a flexible arm configured to move between a latch engagement position at which the wafer connector is latch-engaged to the fitting connector and a latch disengagement position at which the wafer connector is unlatched from the fitting connector. In a case where a first wafer connector is stacked with a second wafer connector including a second latch engaging member including a second flexible arm, when the first flexible arm moves between the latch engagement position and the latch disengagement position in a state where the first engaging portion of the first wafer connector is engaged with the second engaging portion of the second wafer connector, the second flexible arm also moves between the latch engagement position and the latch disengagement position. 
     A fitting connector according to one aspect of the present disclosure defines a plurality of receiving cavities configured to receive a plurality of wafer connectors, and includes an engaged portion configured to engage with a latch portion of the wafer connector received in each of the receiving cavities. The wafer connector is configured to be unlatched from the fitting connector by moving the latch portion by a disengagement distance, and for two of the wafer connectors received in each of at least the first receiving cavity and the second receiving cavity among the plurality of receiving cavities, the first disengagement distance when the latch portion of the first wafer connector is moved in the first receiving cavity is different from the second disengagement distance when the latch portion of the second wafer connector is moved in the second receiving cavity. 
     Advantageous Effects of Invention 
     According to one aspect of the present disclosure, it is possible to improve workability of insertion and removal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating an example of a state in which a plurality of fitting connectors to which a plurality of wafer connectors according to an embodiment are fitted are arranged on a board. 
         FIG. 2  is a perspective view illustrating a stacked type wafer connector and fitting connector according to an embodiment. 
         FIG. 3  is a perspective view of the stacked type wafer connector and fitting connector of  FIG. 2  as viewed from a direction different from that of  FIG. 2 . 
         FIG. 4  is a longitudinal cross-sectional view of the stacked type wafer connector and fitting connector of  FIG. 2 . 
         FIG. 5  is a perspective view illustrating a fitting connector according to an embodiment. 
         FIG. 6  is a perspective view illustrating a state in which a plurality of wafer connectors according to an embodiment are stacked. 
         FIG. 7  is a perspective view of a first wafer connector and a second wafer connector among the plurality of wafer connectors of  FIG. 6 . 
         FIG. 8  is a perspective view illustrating a state in which the first wafer connector and the second wafer connector of  FIG. 7  are stacked. 
         FIG. 9  is a cutaway cross-sectional perspective view of an engaging portion of the wafer connector of  FIG. 6 . 
         FIG. 10  is a cross-sectional perspective view illustrating internal terminals of the wafer connector of  FIG. 6 . 
         FIG. 11  is a cross-sectional view illustrating a latch portion of the wafer connector received in a receiving cavity on the end-side of the fitting connector and the engaged portion of the receiving cavity according to an embodiment. 
         FIG. 12  is a cross-sectional view illustrating the latch portion of the wafer connector received in the receiving cavity on the center-side of the fitting connector and the engaged portion of the receiving cavity according to an embodiment. 
         FIG. 13  is a perspective view illustrating a fitting connector and a stacked type wafer connector according to a modified example. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of a stacked type wafer connector and a fitting connector according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are denoted by the same reference signs, and redundant description will be appropriately omitted. Some of the drawings may be simplified or exaggerated for ease of understanding, and the dimensional ratios or the like are not limited to those illustrated in the drawings. 
     First, a connector assembly  1  including a stacked type wafer connector and a fitting connector according to the present embodiment will be described with reference to  FIG. 1 . As illustrated in  FIG. 1 , for example, the connector assembly  1  is disposed on the board B, and the plurality of connector assemblies  1  are disposed on the board B so as to be arranged along one direction. The plurality of connector assemblies  1  may be disposed in arrangement of a lattice pattern, for example, and the arrangement of the connector assemblies  1  is not particularly limited. The connector assembly  1  includes a fitting connector  10  mounted on a board B and a plurality of stacked type wafer connectors  20  housed in the fitting connector  10 . For example, the fitting connector  10  is a board-mounted connector to be mounted on the board B, and the wafer connector  20  is a stacked type wire mount wafer connector. 
     For example, the fitting connector  10  has a box shape, and a plurality of stacked type wafer connectors  20  can be fitted to (inserted into and removed from) the box-shaped fitting connector  10 . As an example, the fitting connector  10  has a bottomed box shape including a bottom. Each wafer connector  20  has, for example, a plate shape, and is fitted to the fitting connector  10  in a state where a plurality of stacked type wafer connectors  20  are stacked in the thickness direction of the wafer connector  20 . 
     In the following description, the fitting direction of the wafer connector  20  to the fitting connector  10  may be referred to as a direction in which the X-axis extends (X-axis direction), a direction in which the plurality of wafer connectors  20  are arranged in the fitting connector  10  may be referred to as a direction in which the Z-axis extends (Z-axis direction), and a lateral direction intersecting (e.g., orthogonal to) both the X-axis and the Z-axis may be referred to as a direction in which the Y-axis extends (Y-axis direction). In addition, a direction in which the connector assembly  1  is viewed from the board B may be referred to as an upper direction, and a direction in which the board B is viewed from the connector assembly  1  may be referred to as a lower direction. For example, the X-axis direction coincides with the thickness direction of the board B and the direction in which the board B and the connector assembly  1  are arranged. The Y-axis direction coincides with, for example, a direction in which channels  42  (to be described later) of each wafer connector  20  are arranged. The Z-axis direction coincides with, for example, a direction in which the plurality of fitting connectors  10  are arranged or a direction in which the plurality of wafer connectors  20  are stacked. 
       FIG. 2  is a perspective view of the connector assembly  1 .  FIG. 3  is a perspective view of the connector assembly  1  viewed from a direction different from that of  FIG. 2 .  FIG. 4  is a cross-sectional view of the connector assembly  1  obtained by cutting the connector assembly  1  along a plane (XY plane) extending in both the X-axis and the Y-axis. As illustrated in  FIGS. 2 to 4 , a plurality of wafer connectors  20  are disposed along the Z-axis inside the fitting connector  10 , and each wafer connector  20  includes a plurality of terminals  30  and an electrically insulating wafer  40  including a cavity  41  in which the terminals  30  are accommodated. The cavity  41  is divided into a plurality of channels  42 . 
     For example, a plurality of contacts  11  to be inserted into the board B extend from the fitting connector  10 , and each contact  11  has a rod shape extending along the X-axis direction. The fitting connector  10  includes a concave portion  10   b  which is recessed downward (toward the board B) in the bottom surface  18   a  of the bottom portion  18  of the fitting connector  10  and into which the extension portion  11   b  of the insertion portion  11   a  enters, and a hole portion  10   c  through which the insertion portion  11   a  of the contact  11  penetrates along the X-axis. The contact  11  is fixed to the fitting connector  10  in a state in which the insertion portion  11   a  is inserted into the hole portion  10   c  and the extension portion  11   b  enters the concave portion  10   b . The fitting connector  10  includes an open end  12  and a receiving region  13  for receiving the wafer connector  20 . The fitting connector  10  defines a receiving region  13  for receiving a plurality of wafer connectors  20 . For example, the receiving region  13  is a region inside the box-shaped fitting connector  10 , and the open end  12  is a portion that opens on the opposite side of the bottom portion  18  (board B). In the receiving region  13 , for example, a plurality of wafer connectors  20  are fitted to the fitting connector  10  along the X-axis, and terminals  30  within the wafer connectors  20  are connected to (in contact with) contacts  11  extending from the fitting connector  10 . 
     For example, four wafer connectors  20  are fitted to the fitting connector  10 . Each of the plurality of wafer connectors  20  includes a latch engaging portion  25  that engages with the fitting connector  10 . The fitting connector  10  includes an engaged portion  10   d  with which the latch engaging portion  25  is engaged. The wafer connector  20  is fitted to the fitting connector  10  by engaging the latch engaging portion  25  with the engaged portion  10   d.    
     The engaged portion  10   d  of the fitting connector  10  includes, for example, a hole portion  10   f  with which the latch engaging portion  25  is engaged and which penetrates the engaged portion  10   d  in the Y-axis direction. For example, all of the plurality of wafer connectors  20  arranged in the Z-axis direction are engaged with the engaged portion  10   d . However, among the plurality of wafer connectors  20  arranged in the Z-axis direction, the engagement mode of the latch engaging portions  25  of some of the wafer connectors  20  may be different from the engagement mode of the latch engaging portions  25  of the remaining wafer connectors  20 . 
       FIG. 5  is a perspective view of the fitting connector  10 . As illustrated in  FIG. 5 , the contact  11  includes the above-described extension portion  11   b  and a rod-shaped terminal connecting portion  11   c  extending from the extension portion  11   b  to the opposite side of the insertion portion  11   a  and entering the terminal  30 . In addition, the fitting connector  10  includes a first side wall  14  and a second side wall  15 , arranged along the Z-axis direction, and a third side wall  16  and a fourth side wall  17 , arranged along the Y-axis direction. The receiving region  13  is defined by the bottom portion  18 , the first side wall  14 , the second side wall  15 , the third side wall  16 , and the fourth side wall  17  of the above-described fitting connector  10 , and an open end  12  is provided on the opposite side of the bottom portion  18 . 
     The receiving region  13  is partitioned for each wafer connector  20  to be fitted to the fitting connector  10 , for example. The fitting connector  10  includes a plurality of receiving cavities  13   a  for receiving the wafer connectors  20 , and the plurality of receiving cavities  13   a  are partitioned from each other by interposing protrusions  13   b . That is, the receiving cavity  13   a  is defined on each of one side and the other side of the protrusions  13   b  in the Z-axis direction. The protrusion  13   b  is formed by, for example, a protruding surface  13   c  protruding from the inner surface of the fourth side wall  17 , a linear top surface  13   d  extending in the X-axis direction at the protruding end of the protruding surface  13   c , a tapered surface  13   f  inclined in a direction in which the width of the top surface  13   d  decreases at the end of the protruding surface  13   c  on the open end  12  side, and a top face  13   g  located on the open end  12  side of the tapered surface  13   f.    
     The bottom portion  18  includes, for example, a plurality of convex portions  18   b  protruding to the outside (lower side, board B side) of the bottom portion  18  in the X-axis direction, and a board insertion portion  18   c  inserted into the board B. For example, the board insertion portion  18   c  is a metallic portion different from a resin portion (e.g., portions other than the board insertion portion  18   c ) of the fitting connector  10 . The bottom portion  18  has, for example, a rectangular shape, and a convex portion  18   b  is provided at each of four corners of the bottom portion  18 . For example, each of the plurality of convex portions  18   b  is in contact with the upper surface of the board B, and a gap S 1  (see  FIG. 1 ) is formed between a portion of the bottom portion  18  other than the convex portions  18   b  and the upper surface of the board B. The bottom portion  18  includes, for example, a pair of board insertion portions  18   c  arranged along the Y-axis direction, and the fitting connector  10  is fixed to the board B by inserting each of the board insertion portions  18   c  into the board B. 
     The third side wall  16  includes an outer surface  16   a  extending along both the X-axis direction and the Z-axis direction, an inclined surface  16   b  inclined outward in the Y-axis direction from an end of the outer surface  16   a  opposite to the bottom portion  18 , and an outer surface  16   c  extending in both the X-axis direction and the Z-axis direction at an end of the  16   b  opposite to the outer surface  16   a . The outer surface  16   a , the inclined surface  16   b , and the outer surface  16   c  are, for example, all flat. 
     The above-described engaged portion  10   d  is formed on the inclined surface  16   b  and the outer surface  16   c . The engaged portion  10   d  is formed, for example, at a position recessed toward the center of the fitting connector  10  from the inclined surface  16   b  and the outer surface  16   c . As an example, the outer surface  16   c  and the inclined surface  16   b  are formed on both left and right sides of the engaged portion  10   d , and the inclined surface  16   b  is formed on the lower side of the engaged portion  10   d . The engaged portion  10   d  includes, for example, a wall portion  10   g  extending along the X-axis direction and the Z-axis direction, and a plurality of hole portions  10   f  penetrating the wall portion  10   g  in the Y-axis direction. 
     As an example, the wall portion  10   g  includes a top face  10   h  facing upward and an inclined surface  10   j  inclined obliquely from the top face  10   h  toward the inner side and the lower side of the fitting connector  10 . A top face  10   h  of the engaged portion  10   d  is recessed from upper ends  14   a  and  15   a  of the first side wall  14  and the second side wall  15 , respectively, and at least a portion of the plurality of latch engaging portions  25  is exposed to the recessed portion. In this manner, the top face  10   h  of the engaged portion  10   d  is recessed from the upper ends  14   a  and  15   a  of the first side wall  14  and the second side wall  15 , respectively, and at least a portion of the latch engaging portion  25  is exposed to the recessed portion, so that each latch engaging portion  25  can be easily pinched by a finger or the like. 
     The first side wall  14 , the second side wall  15 , and the fourth side wall  17  are, for example, all flat plates. The height of the upper end  17   a  of the fourth side wall  17  is lower than the height of the upper end  14   a  of the first side wall  14  and the height of the upper end  15   a  of the second side wall  15 . The height of the upper end  17   a  of the fourth side wall  17  may be substantially the same as the height of the top face  10   h  of the engaged portion  10   d  of the third side wall  16 . A protruding portion  26 , which will be described later, of the wafer connector  20  protrudes from an upper end  17   a  of the fourth side wall  17 . 
       FIG. 6  is a perspective view illustrating a plurality of stacked wafer connectors  20 .  FIG. 7  is a perspective view illustrating a state in which the two wafer connectors  20  are separated from each other.  FIG. 8  is a perspective view illustrating a state in which two wafer connectors  20  are engaged with each other. As illustrated in  FIGS. 6, 7, and 8 , for example, a plurality of plate-shaped wafer connectors  20  are stacked along the Z-axis direction. As described above, each wafer connector  20  includes a terminal  30  and an electrically insulating wafer  40 . The wafer  40  has, for example, a plate-shape extending in the X-axis direction and the Y-axis direction and having a thickness in the Z-axis direction. 
     The wafer  40  of the wafer connector  20  includes a first end surface  43  and a second end surface  44 , arranged along the X-axis direction, a first side surface  45  and a second side surface  46 , arranged along the Y-axis direction, and a first base portion  47  and a second base portion  48 , arranged along the Z-axis direction. The first end surface  43  and the second end surface  44  face each other, and the first base portion  47  and the second base portion  48  extend between the first end surface  43  and the second end surface  44 . The first side surface  45  and the second side surface  46  face each other, and the first base portion  47  and the second base portion  48  extend between the first side surface  45  and the second side surface  46 . The cavity  41  is defined between the first base portion  47  and the second base portion  48 . 
     The first end surface  43  is a portion that receives an external terminal to be inserted, and has, for example, a rectangular shape that faces the X-axis direction and extends long in the Y-axis direction. That is, the first end surface  43  has a rectangular shape including a long side extending in the Y-axis direction and a short side extending in the Z-axis direction. As an example, the first end surface  43  has a planar shape. In the first end surface  43 , for example, openings  41   a  of the plurality of cavities  41  arranged along the Y-axis direction are formed. As an example, each opening  41   a  has a rectangular shape. 
     The second end surface  44  faces, for example, the opposite side of the first end surface  43  and receives the plurality of contacts  11  extending from the fitting connector  10 . The second end surface  44  has, for example, a rectangular shape that faces the X-axis direction and extends long in the Y-axis direction, similarly to the first end surface  43 . The first side surface  45  is provided with a protruding portion  26  protruding in the Y-axis direction at one end on the first end surface  43  side. The first side surface  45  has, for example, a rectangular shape extending long in the X-axis direction. The protruding portion  26  includes an inclined surface  26   a  extending obliquely with respect to both the X-axis direction and the Y-axis direction, and a top surface  26   b  located between the inclined surface  26   a  and the first end surface  43  side. 
     For example, the second side surface  46  extends from the first end surface  43  along the X-axis direction. The second side surface  46  is provided with a protruding portion  46   b  protruding from the side opposite to the first end surface  43  (the second end surface  44  side) and a latch engaging portion  25  extending from the protruding portion  46   b  along the second side surface  46 . The second side surface  46  has, for example, a rectangular shape including a long side along the X-axis direction and a short side along the Z-axis direction. The protruding portion  46   b  includes a side surface  46   c  extending from the second side surface  46  in the Y-axis direction and the Z-axis direction, and a top surface  46   d  extending in the X-axis direction and the Z-axis direction at an end of the side surface  46   c  opposite to the second side surface  46 . 
     The latch engaging portion  25  is formed integrally with the wafer  40 . The latch engaging portion  25  includes a plate-shaped flexible arm  27  continuous with the top surface  46   d , a latch portion  28  protruding outward in the Y-axis direction from the flexible arm  27 , and a pressing portion  29  protruding outward in the Y-axis direction from the distal end of the flexible arm  27  and pressed in the Y-axis direction by a finger or the like. The flexible arm  27  extends from the side surface  46   c  of the protruding portion  46   b  toward the first end surface  43 , and an inclined surface  27   a  inclined with respect to both the X-axis direction and the Y-axis direction is formed on the opposite side of the pressing portion  29  at the distal end of the flexible arm  27 . 
     For example, a curved surface  27   b  that connects the flexible arm  27  and the side surface  46   c  to each other is formed between the flexible arm  27  and the side surface  46   c . A gap S 2  is formed between the second side surface  46  and the latch engaging portion  25  (flexible arm  27 ). The pressing portion  29  is a portion that is pressed toward the second side surface  46 . When the pressing portion  29  is pressed, the flexible arm  27  bends in the Y-axis direction with the side surface  46   c  as a starting point, and the flexible arm  27  bends in the Y-axis direction to engage and disengage the latch portion  28 . 
     The engagement and disengagement of the latch portions  28  are performed in conjunction with each other in the plurality of integrated wafer connectors  20 , for example.  FIG. 6  illustrates a state of a latch engagement position where the wafer connector  20  is latch-engaged to the fitting connector  10 . For example, the latch engaging portions  25  of the plurality of wafer connectors  20  move between the latch engagement position and the latch disengagement position by bending in conjunction with each other. The latch disengagement position indicates a state in which the plurality of latch engaging portions  25  are bent so that the plurality of latch engaging portions  25  are closer to the second side surface  46  than in the state illustrated in  FIG. 6 , for example. Details of the latch engagement position and the latch disengagement position by the latch engaging portion  25  will be described later. 
     The latch portion  28  is provided between the side surface  46   c  (the proximal end of the flexible arm  27 ) and the pressing portion  29  (the distal end of the flexible arm  27 ). The latch portion  28  includes a tapered surface  28   a  inclined from the flexible arm  27  in both the X-axis direction and the Y-axis direction, a top surface  28   b  extending along the X-axis direction and the Z-axis direction at an end portion of the tapered surface  28   a  on the outer side in the Y-axis direction, and a side surface  28   c  extending along the Y-axis direction and the Z-axis direction on the side of the top surface  28   b  opposite to the tapered surface  28   a . The side surface  28   c  is a portion facing the lower surface of the wall portion  10   g  of the engaged portion  10   d , and the top surface  28   b  and the tapered surface  28   a  are portions that are latch-engaged with the engaged portion  10   d  and exposed from the hole portion  10   f.    
     The pressing portion  29  includes a curved surface  29   a  extending from the flexible arm  27 , a first protruding surface  29   b  extending from the curved surface  29   a , an inclined surface  29   c  extending from the first protruding surface  29   b , a top surface  29   d , and a second protruding surface  29   e  extending from the top surface  29   d  on the side opposite to the inclined surface  29   c . The curved surface  29   a  is inclined with respect to both the X-axis direction and the Y-axis direction from the flexible arm  27 . The first protruding surface  29   b  extends in the Y-axis direction and the Z-axis direction from a side of the curved surface  29   a  opposite to the flexible arm  27 , and the inclined surface  29   c  is inclined with respect to both the X-axis direction and the Y-axis direction from an end of the first protruding surface  29   b  opposite to the curved surface  29   a . The top surface  29   d  is located on the side of the inclined surface  29   c  opposite to the first protruding surface  29   b , and the second protruding surface  29   e  extends along the Y-axis direction and the Z-axis direction on the side of the top surface  29   d  opposite to the inclined surface  29   c . The top surface  29   d  is a portion to which a finger or the like is applied. When the top surface  29   d  is pressed by the finger or the like, the flexible arm  27  is bent toward the center of the wafer connector  20  in the Y-axis direction. 
     The first base portion  47  includes, for example, a surface  47   a  facing the other wafer connector  20  (wafer  40 ) along the Z-axis direction, and a protrusion  47   b  extending outward from the surface  47   a  in the thickness direction of the wafer  40  (along the Z-axis direction) and an engaging portion  49   b . The surface  47   a  is, for example, flat, and the protrusion  47   b  is cylindrical. The engaging portion  49   b  has, for example, a cylindrical shape similarly to the protrusion  47   b . As an example, the height of the engaging portion  49   b  is higher than the height of the protrusion  47   b . However, the shapes of the protrusion  47   b  and the engaging portion  49   b  are not limited to the cylindrical shape, and may be, for example, a prism shape, an oval cylindrical shape, or the like, and can be appropriately changed. 
     The protrusion  47   b  and the engaging portion  49   b  of the wafer connector  20  (e.g., a first wafer connector) are, for example, portions to which another wafer connector  20  (e.g., a second wafer connector) is coupled. The first base portion  47  includes, for example, a plurality of protrusions  47   b  and an engaging portion  49   b . The plurality of protrusions  47   b  are disposed, for example, at one end of the first base portion  47  in the Y-axis direction and at the other end of the first base portion  47  in the Y-axis direction, respectively. In this way, since the protrusions  47   b  are disposed at one end of the first base portion  47  in the Y-axis direction and at the other end of the first base portion  47  in the Y-axis direction, respectively, it is possible to firmly couple with other wafer connectors  20  at both ends in the Y-axis direction. 
     For example, in at least one end portion in the Y-axis direction (e.g., an end portion on the protruding portion  26  side), the plurality of protrusions  47   b  are respectively disposed at one end in the X-axis direction and at the other end in the X-axis direction. Since the protrusions  47   b  are respectively disposed at one end in the X-axis direction and the other end in the X-axis direction, it is possible to firmly couple with the other wafer connector  20  at both ends in the X-axis direction. In the present embodiment, the set C of two protrusions  47   b  is disposed at each of both end portions in the X-axis direction at the end portion on the protruding portion  26  side in the Y-axis direction (the opposite side of the latch engaging portion  25 ), and the set C of two protrusions  47   b  is disposed at the end portion on the latch engaging portion  25  side in the Y-axis direction and at the end portion on the second end surface  44  side. In each set C, two protrusions  47   b  are arranged side by side along the X-axis direction. Each protrusion  47   b  includes an outer peripheral surface  47   c  extending upward with respect to the surface  47   a , a tapered surface  47   d  located at the upper end of the outer peripheral surface  47   c , and a top surface  47   e  located at the upper end of the tapered surface  47   d.    
     The engaging portion  49   b  is provided in the latch engaging portion  25 . For example, the engaging portion  49   b  protrudes from the flexible arm  27  (e.g., the pressing portion  29 ) of the latch engaging portion  25  along the Z-axis direction. The engaging portion  49   b  is a portion for coupling the latch engaging portion  25  of the wafer connector  20  (e.g., a first wafer connector) to the latch engaging portion  25  of another wafer connector  20  (e.g., a second wafer connector). The plurality of latch engaging portions  25  can be interlocked with the latch engagement position and the latch disengagement position by the engaging portion  49   b . The engaging portion  49   b  includes, for example, a first tapered surface  49   c  protruding from a side surface  27   c  of the flexible arm  27  facing the Z-axis direction, an outer peripheral surface  49   d  extending from the first tapered surface  49   c  in the Z-axis direction, a second tapered surface  49   f  having a reduced diameter at an end of the outer peripheral surface  49   d  on the side opposite to the first tapered surface  49   c , and a top surface  49   g  facing the Z-axis direction on the side of the second tapered surface  49   f  opposite to the outer peripheral surface  49   d.    
     The second base portion  48  includes a surface  48   a  facing another wafer connector  20  (e.g., a second wafer connector) along the Z-axis direction, an opening  48   b  recessed from the surface  48   a  in the thickness direction of the wafer  40  and into which the protrusion  47   b  is inserted, and terminal engaging portions  48   c  and  48   f  with which the terminals  30  inserted into the cavities  41  are engaged. The terminal engaging portions  48   c  and  48   f  are through-holes with which the terminals  30  are engaged. As an example, the terminal engaging portions  48   c  and  48   f  have a rectangular shape. 
     The opening  48   b  is a portion for coupling the wafer  40  of another wafer connector  20  to the wafer  40 . The second base portion  48  includes, for example, a plurality of openings  48   b . The plurality of openings  48   b  are respectively disposed at one end of the second base portion  48  in the Y-axis direction and at the other end of the second base portion  48  in the Y-axis direction. For example, in at least one end portion of the second base portion  48  in the Y-axis direction (e.g., an end portion on the protruding portion  26  side), the opening  48   b  is disposed at each of one end of the second base portion  48  in the X-axis direction and the other end of the second base portion  48  in the X-axis direction. 
     In the present embodiment, the opening  48   b  is disposed at each of both end portions in the X-axis direction and an end portion of the protruding portion  26  side in the Y-axis direction. An opening  48   b  is disposed at an end portion on the latch engaging portion  25  side in the Y-axis direction and an end portion on the second end surface  44  side. The opening  48   b  has, for example, a rectangular shape including a long side in the X-axis direction and a short side in the Y-axis direction. The opening  48   b  includes an inner side surface  48   e  with which the outer peripheral surface  47   c  of the protrusion  47   b  abuts. The inner side surfaces  48   e  are provided in a pair along the width direction (Y-axis direction) of the opening  48   b , for example. 
     The width of the opening  48   b  (the distance between the pair of inner side surfaces  48   e ) is substantially the same as the diameter of the outer peripheral surface  47   c  of the protrusion  47   b . Therefore, when the protrusion  47   b  is pushed into the opening  48   b , the outer peripheral surface  47   c  abuts against each inner side surface  48   e  of the opening  48   b , and the protrusion  47   b  is coupled to the opening  48   b . For example, the two protrusions  47   b  forming the set C are inserted into the one opening  48   b , and the outer peripheral surfaces  47   c  of the two protrusions  47   b  abut on the pair of inner side surfaces  48   e , respectively. In this way, by including one opening  48   b  for a plurality of protrusions  47   b , the number of openings  48   b  can be reduced. 
     As illustrated in  FIG. 9 , the second base portion  48  includes an engaging portion  49   h  that engages with the engaging portion  49   b  of the first base portion  47 . The engaging portion  49   h  is, for example, an engaged portion to be engaged with the engaging portion  49   b  formed in the first base portion  47 . As an example, the engaging portion  49   h  is a hole, into which the engaging portion  49   b  of another wafer  40  is inserted, and is provided in the latch engaging portion  25 . For example, the engaging portion  49   h  is formed on a side surface  27   d  facing opposite to the side surface  27   c  in the flexible arm  27  (e.g., the pressing portion  29 ) of the latch engaging portion  25 . The engaging portion  49   h  includes, for example, an inner peripheral surface  49   j  with which the outer peripheral surface  49   d  of the engaging portion  49   b  abuts, and a tapered surface  49   k  located on the side surface  27   d  side of the inner peripheral surface  49   j . As an example, the diameter of the inner peripheral surface  49   j  is substantially the same as the diameter of the outer peripheral surface  49   d . In this case, the engaging portion  49   b  is firmly engaged with the engaging portion  49   h.    
       FIG. 10  is a sectional perspective view illustrating the internal structure of the wafer  40 . As illustrated in  FIG. 10 , on the second end surface  44  of the wafer  40 , for example, a plurality of hole portions  44   b  arranged in the Y-axis direction are formed, and each hole portion  44   b  penetrates in the X-axis direction in the second end surface  44  and communicates with the cavity  41 . The cavity  41  includes a bottom surface  41   b  to which a fitting portion  32  of the terminal  30  faces along the X-axis direction. 
     A plurality of terminals  30  arranged apart from each other are accommodated in the cavity  41 . Each terminal  30  includes a wire connection portion  31  disposed at a position adjacent to the first end surface  43  and a fitting portion  32  disposed at a position adjacent to the second end surface  44 . The wire connection portion  31  includes a pressure contact portion  35  and a first support portion  36 , and the fitting portion  32  includes a second support portion  37  and a contact arm portion  38 . 
     The fitting portion  32  includes, for example, contact arm portions  38  which are facing each other and have flexibility, and when the fitting portion  32  receives the contacts  11  of the fitting connector  10 , the contacts  11  are received between the pair of contact arm portions  38  which are spread. The second support portion  37  is provided on the wire connection portion  31  side of the contact arm portion  38 . For example, the second support portion  37  includes a pair of arm portions  37   a  facing each other. 
     The first support portion  36  includes, for example, a pair of arm portions  36   a  that receive a wire inserted into the cavity  41  and extending along the X-axis direction. For example, the positions of the pair of arm portions  36   a  in the X-axis direction are shifted from each other. That is, one of the pair of arm portions  36   a  is positioned closer to the end-side in the X-axis direction than the other. The pressure contact portion  35  is a portion that electrically connects the wire inserted into the cavity  41  to the terminal  30 . For example, in a state where the pressure contact portion  35  supports a wire inserted into the cavity  41  from the outside of the wafer  40 , the pressure contact portion  35  electrically connects the wire to the terminal  30 . 
     Next, a fitting structure of the wafer connector  20  with respect to the fitting connector  10  will be described. As illustrated in  FIG. 2 , the respective latch engaging portions  25  of the plurality of wafer connectors  20  arranged in the Z-axis direction are engaged with the engaged portions  10   d  of the fitting connector  10 . For example, among the plurality of wafer connectors  20  arranged in the Z-axis direction, the latch engaging portion  25  of the wafer connector  20  located on the center-side in the Z-axis direction may be deeply engaged with the fitting connector  10 , and the latch engaging portion  25  of the wafer connector  20  located on the end-side in the Z-axis direction may be shallowly engaged with the fitting connector  10 . As an example, among the four wafer connectors  20  arranged in the Z-axis direction, the latch engaging portions  25  of the two wafer connectors  20  located on the center-side in the Z-axis direction may be deeply engaged with the fitting connector  10 , and the latch engaging portions  25  of the two wafer connectors  20  located on the end-side in the Z-axis direction may be shallowly engaged with the fitting connector  10 . 
       FIG. 11  is a cross-sectional view illustrating an example of a latch engagement position in which the first latch engaging portion  25  of the first wafer connector  20 A (wafer  40 A) located on the end-side in the Z-axis direction is engaged with the fitting connector  10 .  FIG. 12  is a cross-sectional view illustrating an example of a latch engagement position in which the second latch engaging portion  25  of the second wafer connector  20 B (wafer  40 B) positioned on the center-side in the Z-axis direction is engaged with the fitting connector  10 . The configurations of the first wafer connector  20 A and the second wafer connector  20 B (wafer  40 A and wafer  40 B) are, for example, the same as the configurations of the wafer connector  20  and the wafer  40  described above. 
     The latch engaging portion  25  of each of the first wafer connector  20 A and the second wafer connector  20 B includes a flexible arm  27 . The first flexible arm  27  of the first wafer connector  20 A moves between a latch engagement position where the first wafer connector  20 A is latch-engaged to the fitting connector  10  and a latch disengagement position where the first wafer connector  20 A is unlatched from the fitting connector  10 . The second flexible arm  27  of the second wafer connector  20 B moves between a latch engagement position where the second wafer connector  20 B is latch-engaged to the fitting connector  10  and a latch disengagement position where the second wafer connector  20 B is unlatched from the fitting connector  10 . As described above, the first wafer connector  20 A and the second wafer connector  20 B are connected to each other by the engaging portion  49   b  and the engaging portion  49   h . For example, when the first flexible arm  27  moves between the latch engagement position and the latch disengagement position in a state in which the first engaging portion  49   b  of the first wafer connector  20 A is engaged with the second engaging portion  49   h  of the second wafer connector  20 B, the second flexible arm  27  also moves between the latch engagement position and the latch disengagement position in conjunction with the first flexible arm  27 . 
     For example,  FIGS. 11 and 12  illustrate the latch-engaged state of each of the first wafer connector  20 A and the second wafer connector  20 B, and transition from the latch-engaged state to the unlatched state occurs when the flexible arm  27  is moved toward the center of the fitting connector  10  by the disengagement distances d 1  and d 2 . For example, the disengagement distance d 1  of the first wafer connector  20 A is a distance between the outer surface (e.g., the top surface  28   b ) of the latch portion  28  of the first wafer connector  20 A and the inner surface (e.g., the inner surface of the wall portion  10   g ) of the engaged portion  10   d.    
     The position of the flexible arm  27  when the flexible arm  27  is bent toward the center-side of the fitting connector  10  by the disengagement distance d 1  is the latch disengagement position. Similarly to the disengagement distance d 1 , the disengagement distance d 2  of the second wafer connector  20 B is a distance between the outer surface of the latch portion  28  of the second wafer connector  20 B and the inner surface of the engaged portion  10   d . The position of the flexible arm  27  when the flexible arm  27  is bent toward the center-side of the fitting connector  10  by the disengagement distance d 2  is the latch disengagement position. 
     When the first wafer connector  20 A is pulled up from the fitting connector  10  in a state where the first wafer connector  20 A is at the latch disengagement position, the first wafer connector  20 A can be pulled out from the fitting connector  10 . As described above, the flexible arm  27  of the second wafer connector  20 B is connected to the flexible arm  27  of the first wafer connector  20 A by interposing the engaging portion  49   b  and the engaging portion  49   h.    
     Thus, when the first wafer connector  20 A is in the latch-engaged state, the second wafer connector  20 B is also in the latch-engaged state, and when the first wafer connector  20 A is in the unlatched state, the second wafer connector  20 B is also in the unlatched state. Therefore, since the second wafer connector  20 B is also pulled up when the first wafer connector  20 A is pulled up from the fitting connector  10 , the second wafer connector  20 B can be pulled out simultaneously with the pulling-out of the first wafer connector  20 A. Therefore, all the wafer connectors  20  can be pulled out only by setting one wafer connector  20  to the unlatched state. 
     As described above, the disengagement distance d 1  of the first wafer connector  20 A is different from the disengagement distance d 2  of the second wafer connector  20 B, for example, the disengagement distance d 1  is smaller than the disengagement distance d 2 . In the present disclosure, the “disengagement distance” indicates a distance by which the latch engaging portion  25  (flexible arm  27 ) moves when transitioning from the latch-engaged state to the unlatched state, and may include an engagement amount by the latch engaging portion  25 . In the present embodiment, for example, the engagement amount is different for each wafer connector  20 . An example of realizing this configuration will be described. As described above, the fitting connector  10  defines the plurality of receiving cavities  13   a  (see  FIG. 5 ) that receive the first wafer connector  20 A and the second wafer connector  20 B, respectively, and includes the engaged portions  10   d  that engage with the latch portions  28  of the first wafer connector  20 A and the second wafer connector  20 B received in the respective receiving cavities  13   a.    
     The width p 1  of the engaged portion  10   d  of the first receiving cavity  13   a  that receives the first wafer connector  20 A may be different from the width p 2  of the engaged portion  10   d  of the second receiving cavity  13   a  that receives the second wafer connector  20 B. For example, the width p 1  of the wall portion  10   g  constituting the engaged portion  10   d  of the first receiving cavity  13   a  may be narrower than the width p 2  of the wall portion  10   g  constituting the engaged portion  10   d  of the second receiving cavity  13   a . Since the width p 1  is smaller than the width p 2 , a configuration in which the disengagement distance d 1  is shorter than the disengagement distance d 2  is realized. The first receiving cavity  13   a  indicates the receiving cavity  13   a  located on the end-side of the fitting connector  10  in the Z-axis direction, and the second receiving cavity  13   a  indicates the receiving cavity  13   a  located on the center-side of the fitting connector  10  in the Z-axis direction. 
     The interval t 1  between the engaged portion  10   d  of the first receiving cavity  13   a  and the flexible arm  27  when the first wafer connector  20 A is received in the first receiving cavity  13   a  may be different from the interval t 2  between the engaged portion  10   d  of the second receiving cavity  13   a  and the flexible arm  27  when the second wafer connector  20 B is received in the second receiving cavity  13   a . For example, the interval t 1  may be wider than the interval t 2 . Since the interval t 1  is wider than the interval t 2 , a configuration in which the disengagement distance d 1  is shorter than the disengagement distance d 2  is realized. The interval t 2  may be 0. In this case, the flexible arm  27  of the second wafer connector  20 B and the engaged portion  10   d  are in contact with each other. 
     Next, effects of the wafer connector  20  and the fitting connector  10  according to the present embodiment will be described. For example, as illustrated in  FIGS. 7 and 8 , in the wafer connector  20  according to the present embodiment, when the first flexible arm  27  moves between the latch engagement position and the latch disengagement position in a state where the first engaging portion  49   b  of the first wafer connector  20  is engaged with the second engaging portion  49   h  of the second wafer connector  20 , the second flexible arm  27  also moves between the latch engagement position and the latch disengagement position. Accordingly, since the plurality of flexible arms  27  can be interlocked with each other between the plurality of wafer connectors  20 , all the wafer connectors  20  can be caused to transition to the unlatched state by only pressing the flexible arm  27  of one wafer connector  20 . Therefore, the plurality of wafer connectors  20  can be easily pulled out together from the fitting connector  10 . Further, since the plurality of wafer connectors  20  can be integrated by engaging the first engaging portion  49   b  of the first wafer connector  20  with the second engaging portion  49   h  of the second wafer connector  20 , the plurality of integrated wafer connectors  20  can be easily inserted into the fitting connector  10 . Therefore, the plurality of wafer connectors  20  can be easily inserted into and removed from the fitting connector  10 . 
     The first engaging portion  49   b  may be a convex portion and the second engaging portion  49   h  may be a concave portion. The first engaging portion may be a concave portion and the second engaging portion may be a convex portion. In this case, the configurations of the first engaging portion and the second engaging portion can be simplified. 
     The wafer  40  may include at least one protrusion  47   b  extending outwardly from the wafer  40 . When the second wafer connector  20  is stacked on the second wafer connector  20 , the at least one protrusion  47   b  may be inserted into the at least one opening  48   b  of the second wafer connector  20 . By inserting at least one protrusion  47   b  into at least one opening  48   b , relative rotation between the first wafer connector  20  and the second wafer connector  20  may be suppressed. In this case, by inserting the protrusion  47   b  into the opening  48   b , it is possible to prevent the wafer connector  20  from sliding in the fitting direction (X-axis direction). Further, the engagement between the plurality of wafer connectors  20  can be strengthened. 
     The stacked first wafer connector  20  and second wafer connector  20  may be fitted to the fitting connector  10 , and the first wafer connector  20  and the second wafer connector  20  may be latch-engaged to the fitting connector  10 . When one of the stacked first wafer connector  20  and second wafer connector  20  is unlatched from the fitting connector  10 , the other of the stacked first wafer connector  20  and second wafer connector  20  may also be unlatched from the fitting connector  10 . In this case, since the latch-engaging of the plurality of wafer connectors  20  with the fitting connector  10  and the unlatching of the plurality of wafer connectors  20  from the fitting connector  10  are performed in conjunction with each other between the plurality of wafer connectors  20 , the insertion and removal can be performed more easily. 
     The wafer  40  may include a first base portion  47  and a second base portion  48 , which extend between the first side surface  45  and the second side surface  46  facing each other and which extend between the first end surface  43  and the second end surface  44  facing each other. The latch engaging portion  25  may extend from the second side surface  46 . The cavity  41  may be defined between the first base portion  47 , the second base portion  48 , the first side surface  45 , the second side surface  46 , the first end surface  43 , and the second end surface  44 . The wafer  40  may receive an external terminal inserted into at least one opening  41   a  defined in the first end surface  43 . The second end surface  44  defines at least one hole  44   b  to be fitted to the fitting connector  10 , and may receive the contacts  11  of the fitting connector  10  through the hole portions  44   b.    
     As illustrated in  FIGS. 5, 11, and 12 , the fitting connector  10  according to the present embodiment defines a plurality of receiving cavities  13   a  for receiving a plurality of wafer connectors  20 , and includes engaged portions  10   d  to be engaged with the latch portions  28  of the wafer connectors  20  received in the respective receiving cavities  13   a . Then, the wafer connector  20  is unlatched from the fitting connector  10  by moving the latch portion  28  by the disengagement distances d 1  and d 2 . 
     For at least two wafer connectors  20  received in each of the first receiving cavity  13   a  and the second receiving cavity  13   a  among the plurality of receiving cavities  13   a , a first disengagement distance d 1  when the latch portion  28  of the first wafer connector  20 A moves in the first receiving cavity  13   a  may be different from a second disengagement distance d 2  when the latch portion  28  of the second wafer connector  20 B moves in the second receiving cavity  13   a . As described above, even when the first disengagement distance d 1  and the second disengagement distance d 2  are different from each other among the plurality of wafer connectors  20 , the plurality of latch portions  28  are engaged and disengaged in conjunction with each other. Therefore, it is possible to easily perform insertion and removal with respect to the fitting connector  10 . 
     The shape of the engaged portion  10   d  of the first receiving cavity  13   a  may be different from the shape of the engaged portion  10   d  of the second receiving cavity  13   a , so that the first disengagement distance d 1  is different from the second disengagement distance d 2 . The expression “the shape of the engaged portion is different” is not limited to the case described above where the width p 1  and the width p 2  are different from each other, and also includes, for example, a case where the engaged portion is partially tapered or the degree of the taper is different, or the like. The wafer connector  20  may also be provided with a flexible arm  27  including a latch portion  28 , and t 2  may be different from t 1 , where t 1  is the interval between the engaged portion  10   d  of the first receiving cavity  13   a  and the flexible arm  27  when the first wafer connector  20 A is received in the first receiving cavity  13   a , and t 2  is the interval between the engaged portion  10   d  of the second receiving cavity  13   a  and the flexible arm  27  when the second wafer connector  20 B is received in the second receiving cavity  13   a . Further, the value of t 2  may be 0. 
     The fitting connector  10  includes a plurality of contacts  11  that abut the terminals  30  of the wafer connector  20 , and the plurality of contacts  11  may be disposed in the plurality of receiving cavities  13   a . In addition, the above-described first receiving cavity  13   a  may be a receiving cavity  13   a , on the end-side, disposed adjacent to the first side wall  14  of the fitting connector  10 , and the second receiving cavity  13   a  may be a receiving cavity  13   a , on the center-side, spaced apart from the first side wall  14  and the second side wall  15  facing the first side wall  14 . 
     In addition, the receiving cavity  13   a  may include end-side receiving cavities  13   a  adjacent to the side walls (e.g., the first side wall  14  and the second side wall  15 ) facing each other and a center-side receiving cavity  13   a  disposed between the pair of end-side receiving cavities  13   a . Each receiving cavity  13   a  may include an engaged portion  10   d  that receives the wafer connector  20  and engages with the latch portion  28  of the wafer connector  20 . Further, the engaged portion  10   d  may extend along the side walls facing each other, and the relationship between the width p 1  of the engaged portion  10   d  (wall portion  10   g ) on each end-side and the width p 2  of the engaged portion  10   d  on each center-side may satisfy p 1 &lt;p 2 . In this case, the latch engagement of the latch portion  28  with the engaged portion  10   d  on the end-side can be made shallower than the latch engagement of the latch portion  28  with the engaged portion  10   d  on the center-side. In addition, since the engagement amount of the latch engaging portion  25  on the center-side is larger than the engagement amount of the latch engaging portion  25  on the end-side, when the latch engaging portion  25  on the center-side having a large engagement amount is operated, the latch engaging portion  25  on the end-side having a small engagement amount can be easily disengaged. Further, the latch engaging portion  25  can be easily disengaged by pressing the pressing portion  29 . Therefore, all the wafer connectors  20  can be pulled out more easily by pressing the pressing portion  29  of the latch engaging portion  25  on the center-side. 
     The embodiments of the wafer connector and the fitting connector according to the present disclosure have been described above. However, the shape, the size, the number, the material, the arrangement, the engagement, or the like of each portion of the wafer connector and the fitting connector according to the present disclosure are not limited to the above-described embodiments, and can be appropriately changed. For example, the shape, the size, the number, the material, and the arrangement of each of the fitting connector  10 , the wafer connector  20 , the terminal  30 , and the wafer  40  are not limited to those in the above-described embodiment and can be appropriately changed. 
     For example, as illustrated in  FIG. 13 , the fitting connector  10  of a connector assembly  51  according to a modified example may include a convex portion  19  protruding from the third side wall  16 . In this case, for example, a convex portion  19  protruding outward (outward in the Y-axis direction) of the fitting connector  10  is formed on the outer surface  16   a  of the third side wall  16 . As an example, the convex portion  19  protrudes in a rectangular shape in a region including the center of the outer surface  16   a . The convex portion  19  may be provided below the engaged portion  10   d  (latch engaging portion  25 ) of the fitting connector  10 . 
     In this way, by providing the convex portion  19 , the convex portion  19  can function as a mark when the fitting position of the wafer connector  20  to be fitted to the fitting connector  10  is searched with a finger. That is, in the case of including the convex portion  19  positioned below the latch engaging portion  25 , the target wafer connector  20  can be easily found by groping the convex portion  19 . Further, the position of the connector assembly  1  on the board B can be easily recognized by groping the convex portion  19 , and the target wafer connector  20  can be easily found. 
     In the above-described embodiment, an example in which four wafer connectors  20  are fitted to one fitting connector  10  has been described. However, the number of wafer connectors fitted to one fitting connector may be two, three, or five or more, and can be appropriately changed. Further, in the above-described embodiment, an example in which the fitting connector  10  of the connector assembly  1  is a board-mounted connector has been described. However, the fitting connector according to the present disclosure may be a connector other than the board-mounted connector, and may be, for example, a relay connector that connects one electrical connector and another electrical connector to each other. 
     REFERENCE SIGNS LIST 
       10 : Fitting connector,  10   b : Concave portion,  10   c ,  10   f ,  44   b : Hole portion,  10   d : Engaged portion,  11 : Contact,  12 : Open end,  13   a : Receiving cavity (First receiving cavity, Second receiving cavity),  14 : First side wall,  15 : Second side wall,  16 : Third side wall,  17 : Fourth side wall,  18   b ,  19 : Convex portion,  20 ,  20 A,  20 B: Wafer connector (First wafer connector, Second wafer connector)  25 : Latch engaging portion,  26 : Protruding portion,  27 : Flexible arm,  28 : Latch portion,  29 : Pressing portion,  30 : Terminal,  40 : Wafer,  41 : Cavity,  41   a : Opening,  43 : First end surface,  44 : Second end surface,  45 : First side surface,  46 : Second side surface,  47 : First base portion,  47   b : Protrusion,  48 : Second base portion,  48   b : Opening,  49   b ,  49   h : Engaging portion (First engaging portion, Second engaging portion), d 1 , d 2 : Disengagement distance, p 1 , p 2 : Width, t 1 , t 2 : Interval