Abstract:
To manufacture a molded connector formed by a primary molding and a secondary molding, a primary molded piece having resin portion integrally formed with terminals and a projection formed on the resin portion is prepared first. The primary molded piece is disposed inside a mold used for the secondary molding such that a distal end of the projection abuts against a part of inner face of the mold. Then resin material is injected into the mold to conduct the secondary molding. The projection of the primary molded piece is deformable in accordance with inspecting pressure of the resin material. After the secondary molded piece is removed from the mold, a shape of the distal end of the projection to judge inferiority of the inspecting pressure of the resin material.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a method of manufacturing a molded connector for forming a molded connector by subjecting a synthetic resin material to secondary molding on the outer sides of a primary molded piece having terminal portions, as well as a primary molded piece for the molded connector. 
     FIG. 7 shows an example of a related molded connector (see Japanese Patent Publication No. 8-2501 93A). 
     This molded connector  90  is comprised of a primary molded piece  97  formed by insert-molding terminals  91  through a synthetic resin-made core  92 , a soft sealant  93  filled in a recessed portion of the core  92  and adhering to the peripheries of the terminals  91 , and a synthetic resin-made connector housing  94  covering the outer sides of the primary molded piece  97 . The core  92 , the sealant  93 , and the connector housing  94  have insulating properties, respectively. 
     The terminals  91  are arranged in two stages in face-to-face relation, and distal end portions of the terminals  91  are projectingly positioned in connector engaging portions  95  and  96  on both sides of the connector housing  94 . For example, a connector portion (not shown) of an apparatus or the like is connected to one connector engaging portion  96 , while a connector (not shown) on the wire harness side is engaged with the other connector engaging portion  95 . Since the terminals  91  are passed through the sealant  93 , the penetration of water or the like from one connector engaging portion  96  to the other connector engaging portion  95  can be prevented. 
     As for the method of manufacturing this molded connector  90 , the plurality of terminals  91  are first insert-molded together with the core  92  which is a synthetic resin material, thereby obtaining the primary molded piece  97 . Insulation is provided for the terminals by the core  92 , and the positioning of the terminals with respect to each other is effected. Next, the sealant  93  is filled in the recessed portion of the core  92  of the primary molded piece  97 . Then, the primary molded piece  97  is set in a mold (not shown), a resin material is injected over the primary molded piece  97  to form the connector housing  94 , thereby obtaining the molded connector  90  which is a secondary molded piece. 
     The reason for performing primary molding (preliminary molding) is to prevent the short-circuiting of the terminals  91  due to the occurrence of the positional offset of the terminals  91  by being pressed by the resin pressure, and partly because the terminals  91  cannot be left exposed since a waterproofing structure is adopted. 
     However, with the above-described related method of manufacturing a molded connector, there have been apprehensions that the primary molded piece  97  is liable to become deformed (the core  92  becomes soft and is liable to become deformed since molding is effected at a high temperature) by being pressed by the high resin pressure during secondary molding (final molding), and that, particularly in the molded multi-way connector using the multiplicity of terminals  91 , short-circuiting can occur due to the offset of the positions of the terminals  91  or the contacting of the terminals, and durability deteriorates due to the occurrence of large stresses and strains in the core  92  of the synthetic resin material, with the result that cracks are liable to occur. 
     For this reason, molding conditions are determined during secondary molding to position and fix the primary molded piece  97 , but much man-hour has been required for the management of the positioning and fixation of the primary molded piece  97 , and much inspection man-hour has been required for performing continuity checks for the total number of the terminals to ensure the perfection of production quality. 
     SUMMARY OF THE INVENTION 
     In view of the above-described problems, the object of the invention is to provide a method of manufacturing a molded connector and the structure of a primary molded piece which make it possible to easily and reliably inspect an inferiority such as deformation of the primary molded piece during secondary molding. 
     In order to achieve the above object, according to the present invention, there is provided a method of manufacturing a molded connector formed by a primary molding and a secondary molding, comprising the steps of: 
     preparing a primary molded piece having resin portion integrally formed with terminals and a projection formed on the resin portion; 
     disposing the primary molded piece inside a mold used for the secondary molding such that a distal end face of the projection abuts against a part of inner face of the mold; 
     injecting resin material into the mold to conduct the secondary molding; and 
     removing a formed secondary molded piece from the mold. 
     The projection is deformable in accordance with inspecting pressure of the resin material. 
     Preferably, the manufacturing method further comprises inspecting a shape of the distal end face of the projection after the secondary molded piece is removed from the mold to judge inferiority of inspecting pressure of the resin material. Here, it is judged that the injecting pressure is inferior when a cross section area of the inspected distal end face increases in comparison with an initial cross section area thereof at a predetermined rate. 
     Therefore, for example, as the operator confirms the shape of the distal end face of the deformable portion, it is possible to easily and reliably detect an inferiority in the resin pressure and deformation of the primary molded piece. Thus, since an inferiority such as the positional offset of the terminal portions of the primary molded piece and cracks in the resin portion can be easily and reliably detected, it is possible to reduce the man-hour required in the management of the positioning and fixation of the primary molded piece and to detect an inferiority without resorting to the continuity check of the terminal portions. In addition, it is also possible to detect even slight inclination of the terminal portions, so that inspection accuracy improves. 
     Preferably, a gate for injecting the resin material is provided on a line extending along and through the projection. 
     Accordingly, since the pressing force based on the resin material injected from the gate is directly transmitted to the projection, the sensing accuracy of the deformable portion is enhanced, and the deformable portion reliably undergoes crushing deformation even with respect to slight abnormal pressure, thereby making it possible to more reliably detect an inferiority such as the deformation of the primary molded piece. 
     Preferably, the mold has a positioning member for supporting the resin portion when the primary molded piece is disposed therein. The primary molded piece includes an engagement member for engaging with the positioning member. 
     Accordingly, the primary molded piece is stably supported by the positioning member and the projection, so that the positioning and fixing accuracy of the primary molded piece inside the mold is enhanced. 
     Preferably, the positioning member extends perpendicular to an extending direction of the projection of the primary molded piece. 
     Accordingly, the primary molded piece can be supported from two-dimensional directions by the positioning member and the projection, so that the positioning and fixing accuracy of the primary molded piece is further enhanced. 
     Preferably, the projection is rib-like member longitudinal direction of which is perpendicular to an extending direction of the terminals. 
     Accordingly, as the elongated rib member undergoes crushing deformation, the distal end face of the rib member is expanded in its widthwise direction, so that the operator and a camera of an automated machine is able to easily detect the deformation of the distal end face, thereby rendering the inspection easier and more reliable. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings: 
     FIG. 1 is a vertical cross-sectional view showing a secondary molding process in the method of manufacturing a molded connector according to one embodiment of the present invention; 
     FIG. 2 is a vertical cross-sectional view showing a deformation inferiority in the primary molded piece during secondary molding; 
     FIG. 3A is a plan view showing the initial shape of a detecting rib which is a deformable portion; 
     FIG. 3B is similarly a plan view showing a deformed state of the rib; 
     FIG. 4 is a vertical cross-sectional view showing a molded multi-way connector which is a secondary molded piece; 
     FIG. 5 is a perspective view showing a detailed example of the primary molded piece; 
     FIG. 6 is a perspective view showing a detailed example of the molded multi-way connector which is the secondary molded piece; and 
     FIG. 7 is a vertical cross-sectional view showing a related molded connector. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, a detailed description will be given of preferred embodiments of the invention. 
     FIGS. 1 to  4  show one embodiment of the method of manufacturing a molded connector. 
     In FIG. 1, reference numeral I denotes a molding tool (mold) for forming a molded multi-way connector  6  (FIG. 4) by secondary molding, and the molding tool  1  is comprised of an upper mold block  2 , a lower mold block  3 , and a lateral mold block  4 . A primary molded piece  5  of the molded multi-way connector  6  (FIG. 4) is set in the molding tool  1 . 
     The upper mold block  2  is formed by an intermediate portion (intermediate molding portion)  9  with a large step for accommodating a substantially rectangular block-shaped resin portion  7  of the primary molded piece  5 , the intermediate portion  9  being located with a gap  8  on the outer side of the resin portion  7 ; a front portion (housing molding portion)  11  continuing in the forward direction from the intermediate portion  9  and having a vacant chamber  10  larger than the intermediate portion  9 , the lateral mold block  4  being accommodated in the vacant chamber  10  and a gap (substituted by numeral  10 ) being formed between the same and the lateral mold block  4 ; and a rear portion (flange molding portion)  12  continuing flatly in the rearward direction from a stepped portion  9   a  of the intermediate portion  9 . A gate  13  for injecting a resin material is provided substantially in the center of the intermediate portion  9 . A small stepped portion  14  is formed on the front end side of the front portion  11  in such a manner as to project inwardly, and a surface  15  continuing from the stepped portion  14  is in contact with the lateral mold block  4 . 
     The lower mold block  3  is formed by an intermediate portion (intermediate molding portion)  17  located with a gap  16  between the same and the resin portion  7  of the primary molded piece  5  and having a substantially gibbous shape in its vertical cross section; a front portion (housing molding portion)  55  continuing in the forward direction from the intermediate portion  17  and communicating with the vacant chamber  10 , a gap  18  being formed between the same and the lateral mold block  4 ; and a rear portion (flange molding portion)  20  continuing in the rearward direction from the intermediate portion  17  and continuing flatly through a U-shaped groove portion  19 . A surface  22  continuing from a stepped portion  21  formed on the front end side of the front portion  55  in such a manner as to project inwardly is in contact with the lateral mold block  4 . 
     The lateral mold block  4  is formed in the shape of a substantially rectangular block, has at the center of its distal end face  23  a horizontally projecting pin portion (positioning and fixing portion)  24  made of a metal, and has therein terminal inserting holes  25  extending in the axial direction from the distal end face  23 . The pin portion  24  is formed of, for example, a metal material integral with the lateral mold block  4  into a horizontal and flat rib shape, and is located in such a manner as to project in such a manner as to oppose the respective intermediate portions  9  and  17  of the upper mold block  2  and the lower mold block  3 . A housing portion  26  of the secondary molded piece  6  (FIG. 4) is formed in the gap  10  between the lateral mold block  4  and the upper mold block  2  and in the gap  18  between the lateral mold block  4  and the lower mold block  3 . The lateral mold block  4  is capable of advancing and retracting in the horizontal direction along the surfaces  15  and  22  at the front end sides of the upper mold block  2  and the lower mold block  3 . A gap  27  is formed between the front end face  23  of the lateral mold block  4  and the resin portion  7  of the primary molded piece  5 . 
     The pin portion  24  is inserted or fitted into the interior of the resin portion  7 , thereby effecting the positioning and fixation of the primary molded piece  5  in its vertical, longitudinal, and transverse directions. The pin portion  24  is not limited to the rib shape, and may be a pair of left and right cylindrical shapes. 
     The primary molded piece  5  includes the substantially rectangular resin portion  7  and a plurality of (a multiplicity of) bus bars  28  which are insert-molded in the resin portion  7 . The resin portion  7  is formed by a substantially rectangular main body portion  29  and a sub body portion  30  projecting downward from a rear portion of the main body portion  29 . An engaging hole (engaging groove)  31  for the pin portion  24  of the lateral mold block  4  is provided horizontally in the center of the front end of the main body portion  29 . The pin portion  24  is fitted in the engaging hole  31  without clearance, and a distal end  24   a  of the pin portion  24  abuts against the bottom surface of the engaging hole  31 , thereby positioning and fixing the primary molded piece  5  in the vertical, transverse, and longitudinal directions. 
     In addition, a rib (deformable portion)  33  for both deformation detection and positioning is provided in such a manner as to project downward from a lower surface  32  of the main body portion  29 , and a distal end  33   a  of the rib  33  abuts against the upper surface of the intermediate portion  17  of the lower mold block  3 , thereby positioning the primary molded piece  5  in the vertical direction. The rib  33  is formed integrally with the main body portion  29 . The rib  33  projects vertically, and is positioned in a direction perpendicular to the pin portion  24 . The position of the pin portion  24  is set in a position symmetrical with the position of the gate  13  of the upper mold block  2 , i.e., in such a position that if a vertical line is drawn from the center of an opening  13   a  of the gate  13 , the vertical line passes the center of the rib  33 . The primary molded piece  5  is reliably positioned and fixed in the three-dimensional directions, i.e., in the longitudinal, vertical, and transverse directions, by the pin portion  24  and the rib  33 . 
     In addition, the sub body portion  30  is accommodated in the U-shaped groove portion  19  of the lower mold block  3 , the lower end of the sub body portion  30  abuts against a bottom surface  19 a of the U-shaped groove portion  19 , and a front end  30 a of the sub body portion  30  abuts against the front end surface of the U-shaped groove portion  19 , thereby supporting the primary molded piece  5  together with the pin portion  24  and the rib  33 . Contact portions  34  of the bus bars  28  are located in such a manner as to be exposed at the lower end of the sub body portion  30 , the contact portions  34  are slightly extended rearward, and the distal ends of the contact portions  34  abut against a rear end surface  19   b  of the U-shaped groove portion  19 . This also supports the primary molded piece  5  in a stable manner. 
     The main body portion  29  may be molded of one kind of resin material; however, in this example, the bus bars  28  are retained and fixed in advance by a pair of upper and lower holders  35  made of a synthetic resin, and in that state a resin material is molded over the holder  35 , thereby obtaining the primary molded piece  5 . The bus bars  28  are fixed to the upper and lower surfaces of both holders  35 , and are thereby arranged in four stages. The engaging hole  31  for insertion of the pin portion  24  is provided in the main body portion  29  between the upper and lower holders  35 . 
     The bus bars  28  have pin-shaped terminal portions  36  on their front end sides, and have the contact portions  34  on their rear end sides. Leading portions  37  of the bus bars  28  on their rear end sides are bent along the rear end of the main body portion  29 , and continue to the contact portions  34 . The bus bars  28  may be directly insert-molded in the resin portion  7  without using the holders  35  as in the related art shown in FIG.  7 . 
     In FIG. 1, a resin material is injected from the gate  13  of the upper mold block  2 . The resin material is filled into each gap formed between the primary molded piece  5 , on the one hand, and the lateral mold block  4 , the upper mold block  2 , and the lower mold block  3 , on the other. Here, in the event that the pressure with which the resin material is injected is too strong, and the primary molded piece  5  is pushed downward and is bent and deformed as shown in FIG. 2, the rib  33  is compressed and crushed between the lower surface  32  of the main body portion  29  and the lower mold block  3 , and the shape of the distal end face  33 a of the rib  33  expands from the normal elongated state shown in FIG. 3A to the elliptical shape shown in FIG.  3 B. In this state, a resin material  38  (FIG. 2) on the outer side hardens, and the shape of the distal end of the rib  33  remains in the elliptically expanded state. Accordingly, when the operator has removed the secondary molded piece  6  from the molding tool  1 , the operator is able to easily confirm the presence or absence of the deformation of the primary molded piece  5  by viewing the shape of the distal end of the rib  33 . 
     Since the rib  33  is located immediately below the gate  13  (symmetrically with the gate  13 ), the rib  33  reacts sensitively to the pressure inferiority in the resin material  38 . Although the rib  33  is capable of reacting to the pressure inferiority and undergoing crushing deformation even if the rib  33  is not located immediately below the gate  13 , the above configuration may detects the pressure inferiority most sensitively. The shape of the rib  33  is not limited to the elongated one, and even if the distal end is a square one, it is possible to visually confirm the deformation caused during crushing (the distal end face becomes somewhat round). By forming the rib  33  in the elongated shape as shown in FIG. 3A, it is possible to easily detect the change in the distal end face  33 a. The fact that the elongated rib  33  is liable to be affected by heat during secondary molding and is liable to deform by abnormal pressure is also a suitable factor as a detecting member. 
     In FIG. 1, if the resin material for secondary molding is injected properly, the resin material  38  is formed on the outer side of the main body portion  29  with uniform thickness&#39; for the upper and lower portions without the deformation of the primary molded piece  5  and the rib  33 , as shown in FIG.  4 . In the state in which the lateral mold block  4  (FIG. 1) is removed, the housing portion  26  is formed, and the terminal portions  36  of the bus bars  28  are positioned in such a manner as to project into a connector engaging chamber  39  of the housing portion  26 . Engaging holes  41  and  31  for the pin portion  24  (FIG. 1) remain open in a bottom wall  40  of the connector engaging chamber  39  and in the main body portion  29  of the primary molded piece  6 , respectively. 
     The terminal portions  36  of the bus bars  28  are positioned in such a manner as to project into the connector engaging chamber  39  of the housing portion  26 , and the contact portions  34  in the rear are positioned in such a manner as to be exposed at a distal end of a connector portion  42 . The resin material  38  is integrated with the rear portion of the sub body portion  30  of the primary molded piece  5  by secondary molding, thereby forming the connector portion  42 . The connector portion  42  is positioned in such a manner as to project from a flange portion  43 . 
     The flange portion  43  is formed by the rear portions (flange molding portions)  12  and  20  of the molding tool  1  shown in FIG.  1 . The connector portion  42  is formed by the U-shaped groove portion  19 . Upper, lower, left, right, and rear wall portions  44  to  46  on the outer sides of the main body portion  29  of the primary molded piece  5  shown in FIG. 4 are formed by the gaps  8 ,  16 , and  47  in the intermediate portions  9  and  17  (FIG.  1 ). The housing portion  26  and the bottom wall  40  are formed by the gaps  10 ,  18 , and  27  in the front portions (housing molding portions)  11  and  55 . 
     FIG. 5 shows a detailed example of the primary molded piece, and FIG. 6 shows a detailed example of the secondary molded piece (molded multi-way connector) formed by using that primary molded piece. Although these examples slightly differ from the structures shown in FIGS. 1 to  4 , a description will be given by using the same reference numerals for convenience sake. FIGS. 5 and 6 respectively show states in which the primary molded piece and the secondary molded piece shown in FIGS. 1 and 4 are inverted. 
     In the primary molded piece  5  in FIG. 5, reference numeral  7  denotes the resin portion,  29  denotes its main body portion, and  30  denotes its sub body portion. A pair of left and right ribs (deformable portions)  33  are provided projectingly on one wall surface  32  of the main body portion  29 , which is parallel to the terminal portions  36 . The ribs  33  extend in an elongated manner in a direction perpendicular to the projecting direction of the terminal portions  36 . The reason for the fact that the ribs  33  are extended in the lateral direction is to stably effect the three-point support by the ribs  33 , the pin portion (positioning and fixing portion)  24 , and the sub body portion  30  in FIG. 1, and also to allow the distal end faces  33   a  of the ribs  33  in the secondary molded piece  6  in FIG. 6 to stably come into contact with the unillustrated apparatus side (if the ribs  33  are elongated in the projecting direction of the terminal portions  36 , the ribs  33  overlap with a protrusion  48  of the flange portion  43  in FIG. 6, and the inspection is difficult). 
     In FIG. 5, the ribs  33  are disposed close to the sub body portion  30  (close to the rear end of the wall surface  32 ), and the distance between the ribs  33  and the engaging hole  31  in a front end wall (front end face)  50  of the main body portion  29  is set to be long. As a result, when the resin material is injected in the state shown in FIG. 1, the primary molded piece  5  in FIG. 5 tends to rotate downward with the pin portion  24  (FIG. 1) as a fulcrum, so that a large force is applied to the ribs  33  through the principle of the lever, thereby allowing the ribs  33  to reacting sensitively to the pressure inferiority in the resin material. 
     In FIG. 5, the laterally elongated engaging hole  31  is provided in the center of the front end wall  50 . The laterally elongated engaging hole  31  corresponds to the laterally elongated pin portion  24 , but both end portions of the engaging hole  31  may be received by a pair of cylindrical pin portions (not shown). The terminal portions  36  are arranged in multiple stages above and below the engaging hole  31 . Grooves  51  for charting the resin are deeply formed in both sides of the main body portion  29  to improve the engageability with the resin material  38  during secondary molding. The contact portions  34  are positioned in parallel in such a manner as to be exposed at a distal end face  30   b  of the sub body portion  30 . 
     In the secondary molded piece (molded multi-way connector) shown in FIG. 6, the distal end faces  33   a  of the ribs  33  (FIG. 5) are positioned in such a manner as to be exposed at the surface of the flange portion  43 , as described above. In this state, the shape of the distal end faces  33 a of the ribs  33  is confirmed visually or by a camera or the like of an automated machine. If the distal end faces  33   a  of the ribs  33  are different from the desired shape, it means that an inferiority of positional offset has occurred in the primary molded piece  5  due to such as the pressure inferiority or dislocation from the pin portion  24  (FIG. 1) during secondary molding. 
     A pair of bushes  53  each having a mounting hole  52  are formed integrally with the flange portion  43 , and when the flange portion  78 , for instance, is mounted directly on an apparatus, the distal end faces  33   a  of the ribs  33  serve as contact surfaces with respect to the apparatus side. The resin material  38  (FIG. 4) is molded around a latter half of the sub body portion  30  shown in FIG. 5 by secondary molding to form the connector portion  42 , which is positioned in such a manner as to project from the flange portion  43 , and electrical connection is established with the apparatus side through the contact portions  34 . 
     Although the present invention has been shown and described with reference to specific preferred embodiments, various changes and modifications will be apparent to those skilled in the art from the teachings herein. Such changes and modifications as are obvious are deemed to come within the spirit, scope and contemplation of the invention as defined in the appended claims.